Manufacturing process used to produce long-acting recombinant factor VIII Fc fusion protein.

PubMed

McCue, Justin; Kshirsagar, Rashmi; Selvitelli, Keith; Lu, Qi; Zhang, Mingxuan; Mei, Baisong; Peters, Robert; Pierce, Glenn F; Dumont, Jennifer; Raso, Stephen; Reichert, Heidi

2015-07-01

Recombinant factor VIII Fc fusion protein (rFVIIIFc) is a long-acting coagulation factor approved for the treatment of hemophilia A. Here, the rFVIIIFc manufacturing process and results of studies evaluating product quality and the capacity of the process to remove potential impurities and viruses are described. This manufacturing process utilized readily transferable and scalable unit operations and employed multi-step purification and viral clearance processing, including a novel affinity chromatography adsorbent and a 15 nm pore size virus removal nanofilter. A cell line derived from human embryonic kidney (HEK) 293H cells was used to produce rFVIIIFc. Validation studies evaluated identity, purity, activity, and safety. Process-related impurity clearance and viral clearance spiking studies demonstrate robust and reproducible removal of impurities and viruses, with total viral clearance >8-15 log10 for four model viruses (xenotropic murine leukemia virus, mice minute virus, reovirus type 3, and suid herpes virus 1). Terminal galactose-α-1,3-galactose and N-glycolylneuraminic acid, two non-human glycans, were undetectable in rFVIIIFc. Biochemical and in vitro biological analyses confirmed the purity, activity, and consistency of rFVIIIFc. In conclusion, this manufacturing process produces a highly pure product free of viruses, impurities, and non-human glycan structures, with scale capabilities to ensure a consistent and adequate supply of rFVIIIFc. Copyright © 2015 Biogen. Published by Elsevier Ltd.. All rights reserved.

Differential T cell response against BK virus regulatory and structural antigens: A viral dynamics modelling approach.

PubMed

Blazquez-Navarro, Arturo; Schachtner, Thomas; Stervbo, Ulrik; Sefrin, Anett; Stein, Maik; Westhoff, Timm H; Reinke, Petra; Klipp, Edda; Babel, Nina; Neumann, Avidan U; Or-Guil, Michal

2018-05-01

BK virus (BKV) associated nephropathy affects 1-10% of kidney transplant recipients, leading to graft failure in about 50% of cases. Immune responses against different BKV antigens have been shown to have a prognostic value for disease development. Data currently suggest that the structural antigens and regulatory antigens of BKV might each trigger a different mode of action of the immune response. To study the influence of different modes of action of the cellular immune response on BKV clearance dynamics, we have analysed the kinetics of BKV plasma load and anti-BKV T cell response (Elispot) in six patients with BKV associated nephropathy using ODE modelling. The results show that only a small number of hypotheses on the mode of action are compatible with the empirical data. The hypothesis with the highest empirical support is that structural antigens trigger blocking of virus production from infected cells, whereas regulatory antigens trigger an acceleration of death of infected cells. These differential modes of action could be important for our understanding of BKV resolution, as according to the hypothesis, only regulatory antigens would trigger a fast and continuous clearance of the viral load. Other hypotheses showed a lower degree of empirical support, but could potentially explain the clearing mechanisms of individual patients. Our results highlight the heterogeneity of the dynamics, including the delay between immune response against structural versus regulatory antigens, and its relevance for BKV clearance. Our modelling approach is the first that studies the process of BKV clearance by bringing together viral and immune kinetics and can provide a framework for personalised hypotheses generation on the interrelations between cellular immunity and viral dynamics.

Quality by design approach for viral clearance by protein a chromatography

PubMed Central

Zhang, Min; Miesegaes, George R; Lee, Michael; Coleman, Daniel; Yang, Bin; Trexler-Schmidt, Melody; Norling, Lenore; Lester, Philip; Brorson, Kurt A; Chen, Qi

2014-01-01

Protein A chromatography is widely used as a capture step in monoclonal antibody (mAb) purification processes. Antibodies and Fc fusion proteins can be efficiently purified from the majority of other complex components in harvested cell culture fluid (HCCF). Protein A chromatography is also capable of removing modest levels of viruses and is often validated for viral clearance. Historical data mining of Genentech and FDA/CDER databases systematically evaluated the removal of model viruses by Protein A chromatography. First, we found that for each model virus, removal by Protein A chromatography varies significantly across mAbs, while remains consistent within a specific mAb product, even across the acceptable ranges of the process parameters. In addition, our analysis revealed a correlation between retrovirus and parvovirus removal, with retrovirus data generally possessing a greater clearance factor. Finally, we describe a multivariate approach used to evaluate process parameter impacts on viral clearance, based on the levels of retrovirus-like particles (RVLP) present among process characterization study samples. It was shown that RVLP removal by Protein A is robust, that is, parameter effects were not observed across the ranges tested. Robustness of RVLP removal by Protein A also correlates with that for other model viruses such as X-MuLV, MMV, and SV40. The data supports that evaluating RVLP removal using process characterization study samples can establish multivariate acceptable ranges for virus removal by the protein A step for QbD. By measuring RVLP instead of a model retrovirus, it may alleviate some of the technical and economic challenges associated with performing large, design-of-experiment (DoE)—type virus spiking studies. This approach could also serve to provide useful insight when designing strategies to ensure viral safety in the manufacturing of a biopharmaceutical product. PMID:23860745

Latency reversal and viral clearance to cure HIV-1.

PubMed

Margolis, David M; Garcia, J Victor; Hazuda, Daria J; Haynes, Barton F

2016-07-22

Research toward a cure for human immunodeficiency virus type 1 (HIV-1) infection has joined prevention and treatment efforts in the global public health agenda. A major approach to HIV eradication envisions antiretroviral suppression, paired with targeted therapies to enforce the expression of viral antigen from quiescent HIV-1 genomes, and immunotherapies to clear latent infection. These strategies are targeted to lead to viral eradication--a cure for AIDS. Paired testing of latency reversal and clearance strategies has begun, but additional obstacles to HIV eradication may emerge. Nevertheless, there is reason for optimism that advances in long-acting antiretroviral therapy and HIV prevention strategies will contribute to efforts in HIV cure research and that the implementation of these efforts will synergize to markedly blunt the effect of the HIV pandemic on society. Copyright © 2016, American Association for the Advancement of Science.

Mathematical modeling of viral kinetics: a tool to understand and optimize therapy.

PubMed

Layden, Thomas J; Layden, Jennifer E; Ribeiro, Ruy M; Perelson, Alan S

2003-02-01

One theme that continues to emerge from these studies is the relevance and need for a strong IFN effectiveness. In the prediction studies, the importance of IFN effectiveness for eventual clearance of the virus is present. In the study by Layden et al, the relevance of the viral load at the end of the first phase and IFN effectiveness, to the subsequent second-phase viral decline, is discussed. In the recently developed triphasic model by Bergmann et al, it is illustrated how, theoretically, the viral load at the end of the first phase could impact the second-phase viral decline and eventual clearance of the virus. And, in the investigation into the difference in viral dynamics between African Americans and Caucasians, it appears that a strong effectiveness and first-phase log drop is crucial for virus eradication. More work needs to be completed to understand better why the effectiveness is so crucial for elimination of the virus, and why the effectiveness varies so significantly from one person to another, or from one genotype to another. In a rather short time, the study of viral kinetics has improved our understanding of HCV infection, especially in relation to treatment response. Information has been gleaned on the rapid turnover and clearance rate of the virus, the mode of action of IFN, and the dose-dependence of IFN in inhibiting viral production. Such information has been used to challenge the way we treat patients, understand the difference between nonresponders and responders, gain insight into possible mechanisms of treatment resistance, and predict treatment response. As newer drugs emerge, viral kinetic studies should be able to shed light on the dose-dependent efficacy and mode of action of these newer forms of therapy. The use of kinetics needs to be extended to other areas, such as the study and treatment of acute HCV infection as well as following liver transplantation (see article by Drs. Pawlotsky and Rosen). If the past is any indication of the usefulness of mathematical modeling and kinetics in the study of viruses, continued employment of these tools will only prove beneficial.

Colony-Stimulating Factor 1 Receptor Antagonists Sensitize Human Immunodeficiency Virus Type 1-Infected Macrophages to TRAIL-Mediated Killing

PubMed Central

Cunyat, Francesc; Rainho, Jennifer N.; West, Brian; Swainson, Louise; McCune, Joseph M.

2016-01-01

ABSTRACT Strategies aimed at eliminating persistent viral reservoirs from HIV-1-infected individuals have focused on CD4+ T-cell reservoirs. However, very little attention has been given to approaches that could promote elimination of tissue macrophage reservoirs. HIV-1 infection of macrophages induces phosphorylation of colony-stimulating factor 1 receptor (CSF-1R), which confers resistance to apoptotic pathways driven by tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), thereby promoting viral persistence. In this study, we assessed whether CSF-1R antagonists (PLX647, PLX3397, and PLX5622) restored apoptotic sensitivity of HIV-1-infected macrophages in vitro. PLX647, PLX3397, and PLX5622 at clinically relevant concentrations blocked the activation of CSF-1R and reduced the viability of infected macrophages, as well as the extent of viral replication. Our data show that strategies targeting monocyte colony-stimulating factor (MCSF) signaling could be used to promote elimination of HIV-1-infected myeloid cells and to contribute to the elimination of persistent viral reservoirs. IMPORTANCE As the HIV/AIDS research field explores approaches to eliminate HIV-1 in individuals on suppressive antiviral therapy, those approaches will need to eliminate both CD4+ T-cell and myeloid cell reservoirs. Most of the attention has focused on CD4+ T-cell reservoirs, and scant attention has been paid to myeloid cell reservoirs. The distinct nature of the infection in myeloid cells versus CD4+ T cells will likely dictate different approaches in order to achieve their elimination. For CD4+ T cells, most strategies focus on promoting virus reactivation to promote immune-mediated clearance and/or elimination by viral cytopathicity. Macrophages resist viral cytopathic effects and CD8+ T-cell killing. Therefore, we have explored clearance strategies that render macrophages sensitive to viral cytopathicity. This research helps inform the design of strategies to promote clearance of the macrophage reservoir in infected individuals on suppressive antiviral therapy. PMID:27122585

Viral safety characteristics of Flebogamma DIF, a new pasteurized, solvent-detergent treated and Planova 20 nm nanofiltered intravenous immunoglobulin.

PubMed

Caballero, Santiago; Nieto, Sandra; Gajardo, Rodrigo; Jorquera, Juan I

2010-07-01

A new human liquid intravenous immunoglobulin product, Flebogamma DIF, has been developed. This IgG is purified from human plasma by cold ethanol fractionation, PEG precipitation and ion exchange chromatography. The manufacturing process includes three different specific pathogen clearance (inactivation/removal) steps: pasteurization, solvent/detergent treatment and Planova nanofiltration with a pore size of 20 nm. This study evaluates the pathogen clearance capacity of seven steps in the production process for a wide range of viruses through spiking experiments: the three specific steps mentioned above and also four more production steps. Infectivity of samples was measured using a Tissue Culture Infectious Dose assay (log(10) TCID(50)) or Plaque Forming Units assay (log(10) PFU). Validation studies demonstrated that each specific step cleared more than 4 log(10) for all viruses assayed. An overall viral clearance between > or =13.33 log(10) and > or =25.21 log(10), was achieved depending on the virus and the number of steps studied for each virus. It can be concluded that Flebogamma DIF has a very high viral safety profile. 2010 The International Association for Biologicals. Published by Elsevier Ltd. All rights reserved.

Impaired clearance of influenza A virus in obese, leptin receptor deficient mice is independent of leptin signaling in the lung epithelium and macrophages.

PubMed

Radigan, Kathryn A; Morales-Nebreda, Luisa; Soberanes, Saul; Nicholson, Trevor; Nigdelioglu, Recep; Cho, Takugo; Chi, Monica; Hamanaka, Robert B; Misharin, Alexander V; Perlman, Harris; Budinger, G R Scott; Mutlu, Gökhan M

2014-01-01

During the recent H1N1 outbreak, obese patients had worsened lung injury and increased mortality. We used a murine model of influenza A pneumonia to test the hypothesis that leptin receptor deficiency might explain the enhanced mortality in obese patients. We infected wild-type, obese mice globally deficient in the leptin receptor (db/db) and non-obese mice with tissue specific deletion of the leptin receptor in the lung epithelium (SPC-Cre/LepR fl/fl) or macrophages and alveolar type II cells (LysM-Cre/Lepr fl/fl) with influenza A virus (A/WSN/33 [H1N1]) (500 and 1500 pfu/mouse) and measured mortality, viral clearance and several markers of lung injury severity. The clearance of influenza A virus from the lungs of mice was impaired in obese mice globally deficient in the leptin receptor (db/db) compared to normal weight wild-type mice. In contrast, non-obese, SP-C-Cre+/+/LepR fl/fl and LysM-Cre+/+/LepR fl/fl had improved viral clearance after influenza A infection. In obese mice, mortality was increased compared with wild-type mice, while the SP-C-Cre+/+/LepR fl/fl and LysM-Cre+/+/LepR fl/fl mice exhibited improved survival. Global loss of the leptin receptor results in reduced viral clearance and worse outcomes following influenza A infection. These findings are not the result of the loss of leptin signaling in lung epithelial cells or macrophages. Our results suggest that factors associated with obesity or with leptin signaling in non-myeloid populations such as natural killer and T cells may be associated with worsened outcomes following influenza A infection.

The Immune Response in Measles: Virus Control, Clearance and Protective Immunity.

PubMed

Griffin, Diane E

2016-10-12

Measles is an acute systemic viral infection with immune system interactions that play essential roles in multiple stages of infection and disease. Measles virus (MeV) infection does not induce type 1 interferons, but leads to production of cytokines and chemokines associated with nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) signaling and activation of the NACHT, LRR and PYD domains-containing protein (NLRP3) inflammasome. This restricted response allows extensive virus replication and spread during a clinically silent latent period of 10-14 days. The first appearance of the disease is a 2-3 day prodrome of fever, runny nose, cough, and conjunctivitis that is followed by a characteristic maculopapular rash that spreads from the face and trunk to the extremities. The rash is a manifestation of the MeV-specific type 1 CD4⁺ and CD8⁺ T cell adaptive immune response with lymphocyte infiltration into tissue sites of MeV replication and coincides with clearance of infectious virus. However, clearance of viral RNA from blood and tissues occurs over weeks to months after resolution of the rash and is associated with a period of immunosuppression. However, during viral RNA clearance, MeV-specific antibody also matures in type and avidity and T cell functions evolve from type 1 to type 2 and 17 responses that promote B cell development. Recovery is associated with sustained levels of neutralizing antibody and life-long protective immunity.

Transitional probability-based model for HPV clearance in HIV-1-positive adolescent females.

PubMed

Kravchenko, Julia; Akushevich, Igor; Sudenga, Staci L; Wilson, Craig M; Levitan, Emily B; Shrestha, Sadeep

2012-01-01

HIV-1-positive patients clear the human papillomavirus (HPV) infection less frequently than HIV-1-negative. Datasets for estimating HPV clearance probability often have irregular measurements of HPV status and risk factors. A new transitional probability-based model for estimation of probability of HPV clearance was developed to fully incorporate information on HIV-1-related clinical data, such as CD4 counts, HIV-1 viral load (VL), highly active antiretroviral therapy (HAART), and risk factors (measured quarterly), and HPV infection status (measured at 6-month intervals). Data from 266 HIV-1-positive and 134 at-risk HIV-1-negative adolescent females from the Reaching for Excellence in Adolescent Care and Health (REACH) cohort were used in this study. First, the associations were evaluated using the Cox proportional hazard model, and the variables that demonstrated significant effects on HPV clearance were included in transitional probability models. The new model established the efficacy of CD4 cell counts as a main clearance predictor for all type-specific HPV phylogenetic groups. The 3-month probability of HPV clearance in HIV-1-infected patients significantly increased with increasing CD4 counts for HPV16/16-like (p<0.001), HPV18/18-like (p<0.001), HPV56/56-like (p = 0.05), and low-risk HPV (p<0.001) phylogenetic groups, with the lowest probability found for HPV16/16-like infections (21.60±1.81% at CD4 level 200 cells/mm(3), p<0.05; and 28.03±1.47% at CD4 level 500 cells/mm(3)). HIV-1 VL was a significant predictor for clearance of low-risk HPV infections (p<0.05). HAART (with protease inhibitor) was significant predictor of probability of HPV16 clearance (p<0.05). HPV16/16-like and HPV18/18-like groups showed heterogeneity (p<0.05) in terms of how CD4 counts, HIV VL, and HAART affected probability of clearance of each HPV infection. This new model predicts the 3-month probability of HPV infection clearance based on CD4 cell counts and other HIV-1-related clinical measurements.

Hepatitis C Virus Reinfection and Spontaneous Clearance of Reinfection—the InC3 Study

PubMed Central

Sacks-Davis, Rachel; Grebely, Jason; Dore, Gregory J.; Osburn, William; Cox, Andrea L.; Rice, Thomas M.; Spelman, Timothy; Bruneau, Julie; Prins, Maria; Kim, Arthur Y.; McGovern, Barbara H.; Shoukry, Naglaa H.; Schinkel, Janke; Allen, Todd M.; Morris, Meghan; Hajarizadeh, Behzad; Maher, Lisa; Lloyd, Andrew R.; Page, Kimberly; Hellard, Margaret

2015-01-01

Background. We aimed to characterize the natural history of hepatitis C virus (HCV) reinfection and spontaneous clearance following reinfection (reclearance), including predictors of HCV reclearance. Methods. Data were synthesized from the 9 prospective cohorts of the International Collaboration of Incident Human Immunodeficiency Virus and HCV in Injecting Cohorts study, which evaluated HCV infection outcomes among people who inject drugs. Participants with primary HCV infection were classified as having achieved viral suppression if they had negative results of at least 1 subsequent HCV RNA test. Those with positive results of an HCV RNA test following viral suppression were investigated for reinfection. Viral sequence analysis was used to identify reinfection (defined as detection of heterologous virus with no subsequent detection of the original viral strain). Results. Among 591 participants with acute primary HCV infection, 118 were investigated for reinfection. Twenty-eight participants were reinfected (12.3 cases/100 person-years; 95% confidence interval [CI], 8.5–17.8). Peak HCV RNA level was lower during reinfection than primary infection (P = .011). The proportion of individuals with reclearance 6 months after reinfection was 52% (95% CI, 33%–73%). After adjustment for study site, females with the IFNL4 (formerly IFNL3 and IL28B) rs12979860 CC genotype detected were more likely to have reclearance (hazard ratio, 4.16; 95% CI, 1.24–13.94; P = .021). Conclusions. Sex and IFNL4 genotype are associated with spontaneous clearance after reinfection. PMID:25883387

Toll-like receptor 7 is required for effective adaptive immune responses that prevent persistent virus infection.

PubMed

Walsh, Kevin B; Teijaro, John R; Zuniga, Elina I; Welch, Megan J; Fremgen, Daniel M; Blackburn, Shawn D; von Tiehl, Karl F; Wherry, E John; Flavell, Richard A; Oldstone, Michael B A

2012-06-14

TLR7 is an innate signaling receptor that recognizes single-stranded viral RNA and is activated by viruses that cause persistent infections. We show that TLR7 signaling dictates either clearance or establishment of life-long chronic infection by lymphocytic choriomeningitis virus (LCMV) Cl 13 but does not affect clearance of the acute LCMV Armstrong 53b strain. TLR7(-/-) mice infected with LCMV Cl 13 remained viremic throughout life from defects in the adaptive antiviral immune response-notably, diminished T cell function, exacerbated T cell exhaustion, decreased plasma cell maturation, and negligible antiviral antibody production. Adoptive transfer of TLR7(+/+) LCMV immune memory cells that enhanced clearance of persistent LCMV Cl 13 infection in TLR7(+/+) mice failed to purge LCMV Cl 13 infection in TLR7(-/-) mice, demonstrating that a TLR7-deficient environment renders antiviral responses ineffective. Therefore, methods that promote TLR7 signaling are promising treatment strategies for chronic viral infections. Copyright © 2012 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ribeiro, Ruy; Perelson, Alan S; Smith, Amber M

Relatively little is known about the viral factors contributing to the lethality of the 1918 pandemic, although its unparalleled virulence was likely due in part to the newly discovered PB1-F2 protein. This protein, while unnecessary for replication, increases apoptosis in monocytes, alters viral polymerase activity in vitro, and produces enhanced inflammation and increased secondary pneumonia in vivo. However, the effects the PB1-F2 protein have in vivo remain unclear. To address the mechanisms involved, we intranasally infected groups of mice with either influenza A virus PR8 or a genetically engineered virus that expresses the 1918 PB1-F2 protein on a PR8 background,more » PR8-PB1-F2(1918). Mice inoculated with PR8 had viral concentrations peaking at 72 hours, while those infected with PR8-PB1-F2(1918) reached peak concentrations earlier, 48 hours. Mice given PR8-PB1-F2(1918) also showed a faster decline in viral loads. We fit a mathematical model to these data to estimate parameter values and select the best model. This model supports a lower viral clearance rate and higher infected cell death rate with the PR8-PB1-F2(1918) virus, although the viral production rate may also be higher. We hypothesize that the higher PR8-PB1-F2(1918) viral titers early in an infection are due to both an increase in viral production with decreased viral clearance, and that the faster decline in the later stages of infection result from elevated cell death rates. We discuss the implications these mechanisms have during an infection with a virus expressing a virulent PBI-F2 on the possibility of a pandemic and on the importance of antiviral treatments.« less

Comparative Analysis of Measures of Viral Reservoirs in HIV-1 Eradication Studies

PubMed Central

Lysenko, Elena S.; Bosch, Ronald J.; Lai, Jun; Chioma, Stanley; Emad, Fatemeh; Abdel-Mohsen, Mohamed; Hoh, Rebecca; Hecht, Frederick; Hunt, Peter; Somsouk, Ma; Wong, Joseph; Johnston, Rowena; Siliciano, Robert F.; Richman, Douglas D.; O'Doherty, Una; Palmer, Sarah; Deeks, Steven G.; Siliciano, Janet D.

2013-01-01

HIV-1 reservoirs preclude virus eradication in patients receiving highly active antiretroviral therapy (HAART). The best characterized reservoir is a small, difficult-to-quantify pool of resting memory CD4+ T cells carrying latent but replication-competent viral genomes. Because strategies targeting this latent reservoir are now being tested in clinical trials, well-validated high-throughput assays that quantify this reservoir are urgently needed. Here we compare eleven different approaches for quantitating persistent HIV-1 in 30 patients on HAART, using the original viral outgrowth assay for resting CD4+ T cells carrying inducible, replication-competent viral genomes as a standard for comparison. PCR-based assays for cells containing HIV-1 DNA gave infected cell frequencies at least 2 logs higher than the viral outgrowth assay, even in subjects who started HAART during acute/early infection. This difference may reflect defective viral genomes. The ratio of infected cell frequencies determined by viral outgrowth and PCR-based assays varied dramatically between patients. Although strong correlations with the viral outgrowth assay could not be formally excluded for most assays, correlations achieved statistical significance only for integrated HIV-1 DNA in peripheral blood mononuclear cells and HIV-1 RNA/DNA ratio in rectal CD4+ T cells. Residual viremia was below the limit of detection in many subjects and did not correlate with the viral outgrowth assays. The dramatic differences in infected cell frequencies and the lack of a precise correlation between culture and PCR-based assays raise the possibility that the successful clearance of latently infected cells may be masked by a larger and variable pool of cells with defective proviruses. These defective proviruses are detected by PCR but may not be affected by reactivation strategies and may not require eradication to accomplish an effective cure. A molecular understanding of the discrepancy between infected cell frequencies measured by viral outgrowth versus PCR assays is an urgent priority in HIV-1 cure research. PMID:23459007

HLA-B27 Selects for Rare Escape Mutations that Significantly Impair Hepatitis C Virus Replication and Require Compensatory Mutations

PubMed Central

Neumann-Haefelin, Christoph; Oniangue-Ndza, Cesar; Kuntzen, Thomas; Schmidt, Julia; Nitschke, Katja; Sidney, John; Caillet-Saguy, Célia; Binder, Marco; Kersting, Nadine; Kemper, Michael W.; Power, Karen A.; Ingber, Susan; Reyor, Laura L.; Hills-Evans, Kelsey; Kim, Arthur Y.; Lauer, Georg M.; Lohmann, Volker; Sette, Alessandro; Henn, Matthew R.; Bressanelli, Stéphane; Thimme, Robert; Allen, Todd M.

2011-01-01

HLA-B27 is associated with spontaneous viral clearance in hepatitis C virus (HCV) infection. Viral escape within the immunodominant HLA-B27 restricted HCV-specific CD8+ T cell epitope NS5B2841-2849 (ARMILMTHF) has been shown to be limited by viral fitness costs as well as broad T cell cross-recognition, suggesting a potential mechanism of protection by HLA-B27. Here, we studied the subdominant HLA-B27 restricted epitope NS5B2936-2944 (GRAAICGKY) in order to further define the mechanisms of protection by HLA-B27. We identified a unique pattern of escape mutations within this epitope in a large cohort of HCV genotype 1a infected patients. The predominant escape mutations represented conservative substitutions at the main HLA-B27 anchor residue or a T cell receptor contact site, neither of which impaired viral replication capacity as assessed in a subgenomic HCV replicon system. In contrast, however, in a subset of HLA-B27+ subjects rare escape mutations arose at the HLA-B27 anchor residue R2937, which nearly abolished viral replication. Notably, these rare mutations only occurred in conjunction with the selection of two equally rare, and structurally proximal, upstream mutations. Co-expression of these upstream mutations with the rare escape mutations dramatically restored viral replication capacity from <5% to ≥70% of wild-type levels. Conclusion The selection of rare CTL escape mutations in this HLA-B27 restricted epitope dramatically impairs viral replicative fitness unless properly compensated. These data support a role for the targeting of highly-constrained regions by HLA-B27 in its ability to assert immune control of HCV and other highly variable pathogens. PMID:22006856

Transient FTY720 treatment promotes immune-mediated clearance of a chronic viral infection.

PubMed

Premenko-Lanier, Mary; Moseley, Nelson B; Pruett, Sarah T; Romagnoli, Pablo A; Altman, John D

2008-08-14

For a wide variety of microbial pathogens, the outcome of the infection is indeterminate. In some individuals the microbe is cleared, but in others it establishes a chronic infection, and the factors that tip this balance are often unknown. In a widely used model of chronic viral infection, C57BL/6 mice clear the Armstrong strain of lymphocytic choriomeningitis virus (LCMV), but the clone 13 strain persists. Here we show that the Armstrong strain induces a profound lymphopenia at days 1-3 after infection, but the clone 13 strain does not. If we transiently augment lymphopenia by treating the clone-13-infected mice with the drug FTY720 at days 0-2 after infection, the mice successfully clear the infection by day 30. Clearance does not occur when CD4 T cells are absent at the time of treatment, indicating that the drug is not exerting direct antiviral effects. Notably, FTY720 treatment of an already established persistent infection also leads to viral clearance. In both models, FTY720 treatment preserves or augments LCMV-specific CD4 and CD8 T-cell responses, a result that is counter-intuitive because FTY720 is generally regarded as a new immunosuppressive agent. Because FTY720 targets host pathways that are completely evolutionarily conserved, our results may be translatable into new immunotherapies for the treatment of chronic microbial infections in humans.

Association of TNF-alpha (-308 A/G) and IFN-gamma (+874 A/T) gene polymorphisms in response to spontaneous and treatment induced viral clearance in HCV infected multitransfused thalassemic patients.

PubMed

Biswas, Aritra; Gupta, Nabyendu; Gupta, Debanjali; Datta, Abira; Firdaus, Rushna; Chowdhury, Prosanto; Bhattacharyya, Maitreyee; Sadhukhan, Provash C

2018-06-01

Multitransfused thalassemic individuals are at high risk of developing transfusion transmitted Hepatitis C virus (HCV) infection. The aim of the study was to correlate the effects of host cytokine single nucleotide polymorphisms of TNF-α (-308 A/G) and IFN-γ (+874 A/T) in spontaneous or IFN induced treatment response in the HCV infected thalassemic individuals. A total of 427 HCV sero-reactive thalassemic individuals were processed for HCV viral genomic diversity and host gene polymorphisms analysis of TNF-α (-308 A/G) and IFN-γ (+874 A/T). Out of 427 HCV sero-reactive individuals, 69.09% were found to be HCV RNA positive with genotype 3 as the predominant infecting strain (94.29%). Study highlighted that, A allele was significantly associated with (p < .05) spontaneous clearance of HCV infection and G allele was correlated with viral persistence at TNF-α (-308) gene polymorphism. Whereas in case of IFN-γ (+874) SNPs, A allele was significantly responsible (p < .05) for spontaneous clearance than T allele. Our study also indicated that in relapsed cases, IFN-γ (+874) T allele is more responsible than A allele. Though no significant correlation was found at both TNF-α (-308) and IFN-γ (+874) gene polymorphism among SVR and relapsed thalassemic patients. A allele at both TNF-α (-308) and IFN-γ (+874) were strongly associated with spontaneous clearance among this population. But in case of SVR and relapsed cases no significant association was found. This cytokine gene polymorphisms pattern will help clinicians to take an informed decision about therapeutic management of HCV infected thalassemic individuals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multispecific T cell response and negative HCV RNA tests during acute HCV infection are early prognostic factors of spontaneous clearance

PubMed Central

Spada, E; Mele, A; Berton, A; Ruggeri, L; Ferrigno, L; Garbuglia, A R; Perrone, M P; Girelli, G; Del Porto, P; Piccolella, E; Mondelli, M U; Amoroso, P; Cortese, R; Nicosia, A; Vitelli, A; Folgori, A

2004-01-01

Background/Aims: Hepatitis C virus (HCV) infection results in a high frequency of chronic disease. The aim of this study was to identify early prognostic markers of disease resolution by performing a comprehensive analysis of viral and host factors during the natural course of acute HCV infection. Methods: The clinical course of acute hepatitis C was determined in 34 consecutive patients. Epidemiological and virological parameters, as well as cell mediated immunity (CMI) and distribution of human leukocyte antigens (HLA) alleles were analysed. Results: Ten out of 34 patients experienced self-limiting infection, with most resolving patients showing fast kinetics of viral clearance: at least one negative HCV RNA test during this phase predicted a favourable outcome. Among other clinical epidemiological parameters measured, the self-limiting course was significantly associated with higher median peak bilirubin levels at the onset of disease, and with the female sex, but only the latter parameter was independently associated after multivariate analysis. No significant differences between self-limiting or chronic course were observed for the distribution of DRB1 and DQB1 alleles. HCV specific T cell response was more frequently detected during acute HCV infection, than in patients with chronic HCV disease. A significantly broader T cell response was found in patients with self-limiting infection than in those with chronic evolving acute hepatitis C. Conclusion: The results suggest that host related factors, in particular sex and CMI, play a crucial role in the spontaneous clearance of this virus. Most importantly, a negative HCV RNA test and broad CMI within the first month after onset of the symptoms represent very efficacious predictors of viral clearance and could thus be used as criteria in selecting candidates for early antiviral treatment. PMID:15479691

An OX40/OX40L interaction directs successful immunity to hepatitis B virus

PubMed Central

Publicover, Jean; Gaggar, Anuj; Jespersen, Jillian M.; Halac, Ugur; Johnson, Audra J.; Goodsell, Amanda; Avanesyan, Lia; Nishimura, Stephen L.; Holdorf, Meghan; Mansfield, Keith G.; Judge, Joyce Bousquet; Koshti, Arya; Croft, Michael; Wakil, Adil E.; Rosenthal, Philip; Pai, Eric; Cooper, Stewart; Baron, Jody L.

2018-01-01

Depending on age of acquisition, hepatitis B virus (HBV) can induce a cell-mediated immune response that results in either cure or progressive liver injury. In adult-acquired infection, HBV antigens are usually cleared, whereas in infancy-acquired infection, they persist. Individuals infected during infancy therefore represent the majority of patients chronically infected with HBV (CHB). A therapy that can promote viral antigen clearance in most CHB patients has not been developed and would represent a major health care advance and cost mitigator. Using an age-dependent mouse model of HBV clearance and persistence in conjunction with human blood and liver tissue, we studied mechanisms of viral clearance to identify new therapeutic targets. We demonstrate that age-dependent expression of the costimulatory molecule OX40 ligand (OX40L) by hepatic innate immune cells is pivotal in determining HBV immunity, and that treatment with OX40 agonists leads to improved HBV antigen clearance in young mice, as well as increased strength of T cell responses in young mice and adult mice that were exposed to HBV when they were young and developed a CHB serological profile. Similarly, in humans, we show that hepatic OX40L transcript expression is age-dependent and that increased OX40 expression on peripheral CD4+ T cells in adults is associated with HBV clearance. These findings provide new mechanistic understanding of the immune pathways and cells necessary for HBV immunity and identify potential therapeutic targets for resolving CHB. PMID:29563320

Distinct promoter activation mechanisms modulate noise-driven HIV gene expression

NASA Astrophysics Data System (ADS)

Chavali, Arvind K.; Wong, Victor C.; Miller-Jensen, Kathryn

2015-12-01

Latent human immunodeficiency virus (HIV) infections occur when the virus occupies a transcriptionally silent but reversible state, presenting a major obstacle to cure. There is experimental evidence that random fluctuations in gene expression, when coupled to the strong positive feedback encoded by the HIV genetic circuit, act as a ‘molecular switch’ controlling cell fate, i.e., viral replication versus latency. Here, we implemented a stochastic computational modeling approach to explore how different promoter activation mechanisms in the presence of positive feedback would affect noise-driven activation from latency. We modeled the HIV promoter as existing in one, two, or three states that are representative of increasingly complex mechanisms of promoter repression underlying latency. We demonstrate that two-state and three-state models are associated with greater variability in noisy activation behaviors, and we find that Fano factor (defined as variance over mean) proves to be a useful noise metric to compare variability across model structures and parameter values. Finally, we show how three-state promoter models can be used to qualitatively describe complex reactivation phenotypes in response to therapeutic perturbations that we observe experimentally. Ultimately, our analysis suggests that multi-state models more accurately reflect observed heterogeneous reactivation and may be better suited to evaluate how noise affects viral clearance.

Modeling Zika plasma viral dynamics in non-human primates: insights into viral pathogenesis and antiviral strategies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Best, Katharine; Guedj, Jeremie; Madelain, Vincent

2016-10-24

The recent outbreak of Zika virus (ZIKV) has been associated with fetal abnormalities and neurological complications, prompting global concern. Here we present the first mathematical analysis of the within-host dynamics of plasma ZiKV burden in a non-human primate model, allowing for characterization of the growth and clearance of ZIKV within an individual macaque.

Anti-pre-S responses and viral clearance in chronic hepatitis B virus infection.

PubMed

Budkowska, A; Dubreuil, P; Poynard, T; Marcellin, P; Loriot, M A; Maillard, P; Pillot, J

1992-01-01

Serial sera were collected prospectively during the clinical course of 13 HBsAg carriers with chronic liver disease and analyzed for ALT levels, pre-S1 and pre-S2 antigens and corresponding antibodies and other serological hepatitis B virus markers. In five patients, anti-pre-S1 and anti-pre-S2 antibodies became detectable in multiple serum samples, whereas in eight patients anti-pre-S was never detected or only appeared transiently during the follow-up. The first pattern was associated with normalization of ALT levels and undetectable pre-S antigens and viral DNA by the polymerase chain reaction assay at final follow-up. HBsAg clearance occurred in two of the five patients. The second pattern was one of persistence of HBsAg and pre-S antigens, associated with the presence of serum HBV DNA detectable by spot hybridization or polymerase chain reaction regardless of clinical outcome. These findings demonstrate the occurrence of anti-pre-S antibodies in chronic hepatitis B virus-induced liver disease and associate anti-pre-S appearance with the clearance of hepatitis B virus from serum.

The evolving relationship between adiponectin and insulin sensitivity in hepatitis C patients during viral clearance.

PubMed

Chang, Ming-Ling; Kuo, Chia-Jung; Pao, Li-Heng; Hsu, Chen-Ming; Chiu, Cheng-Tang

2017-10-03

The evolution of the relationship between adiponectin and insulin sensitivity in hepatitis C virus (HCV) patients during viral clearance is unclear and warrants investigation. A prospective study including 747 consecutive chronic hepatitis C (CHC) patients, of whom 546 had completed a course of anti-HCV therapy and underwent pre-, peri- and post-therapy surveys for anthropomorphic, viral, metabolic and hepatic profiles and adiponectin levels, was conducted in a tertiary care center. Multivariate analyses indicated associations of sex, triglyceride levels and hepatic steatosis with adiponectin levels and of triglyceride levels and interferon λ3 (IFNL3) genotype with homeostasis model assessment-estimated insulin resistance (HOMA-IR) levels before anti-HCV therapy. In patients with a sustained virological response (SVR; n = 455), at 24 weeks post-therapy, sex, BMI, aspartate aminotransferase to platelet ratio index (APRI), HOMA-IR and steatosis were associated with adiponectin levels, and IFNL3 genotype was associated with HOMA-IR levels. GEE analysis demonstrated that SVR affected longitudinal trends in adiponectin levels. Compared with pre-therapy levels, adiponectin and APRI levels decreased 24 weeks post-therapy in SVR patients, regardless of baseline insulin resistance (IR). However, HOMA-IR levels decreased in SVR patients with baseline IR but increased in those without baseline IR. Compared with controls, immunohistochemical studies showed that pre-therapy CHC patients had higher hepatic adiponectin expression associated with hepatic fibrosis. During HCV infection, adiponectin may affect insulin sensitivity through triglycerides. After viral clearance, adiponectin levels were directly associated with insulin sensitivity and decreased upon improved hepatic fibrosis; with a link to the IFNL3 genotype, insulin sensitivity improved only in patients with baseline IR.

Influence of enriched environment on viral encephalitis outcomes: behavioral and neuropathological changes in albino Swiss mice.

PubMed

de Sousa, Aline Andrade; Reis, Renata; Bento-Torres, João; Trévia, Nonata; Lins, Nara Alves de Almeida; Passos, Aline; Santos, Zaire; Diniz, José Antonio Picanço; Vasconcelos, Pedro Fernando da Costa; Cunningham, Colm; Perry, Victor Hugh; Diniz, Cristovam Wanderley Picanço

2011-01-11

An enriched environment has previously been described as enhancing natural killer cell activity of recognizing and killing virally infected cells. However, the effects of environmental enrichment on behavioral changes in relation to virus clearance and the neuropathology of encephalitis have not been studied in detail. We tested the hypothesis that environmental enrichment leads to less CNS neuroinvasion and/or more rapid viral clearance in association with T cells without neuronal damage. Stereology-based estimates of activated microglia perineuronal nets and neurons in CA3 were correlated with behavioral changes in the Piry rhabdovirus model of encephalitis in the albino Swiss mouse. Two-month-old female mice maintained in impoverished (IE) or enriched environments (EE) for 3 months were behaviorally tested. After the tests, an equal volume of Piry virus (IEPy, EEPy)-infected or normal brain homogenates were nasally instilled. Eight days post-instillation (dpi), when behavioral changes became apparent, brains were fixed and processed to detect viral antigens, activated microglia, perineuronal nets, and T lymphocytes by immuno- or histochemical reactions. At 20 or 40 dpi, the remaining animals were behaviorally tested and processed for the same markers. In IEPy mice, burrowing activity decreased and recovered earlier (8-10 dpi) than open field (20-40 dpi) but remained unaltered in the EEPy group. EEPy mice presented higher T-cell infiltration, less CNS cell infection by the virus and/or faster virus clearance, less microgliosis, and less damage to the extracellular matrix than IEPy. In both EEPy and IEPy animals, CA3 neuronal number remained unaltered. The results suggest that an enriched environment promotes a more effective immune response to clear CNS virus and not at the cost of CNS damage.

The evolving relationship between adiponectin and insulin sensitivity in hepatitis C patients during viral clearance

PubMed Central

Chang, Ming-Ling; Kuo, Chia-Jung; Pao, Li-Heng; Hsu, Chen-Ming; Chiu, Cheng-Tang

2017-01-01

ABSTRACT Background: The evolution of the relationship between adiponectin and insulin sensitivity in hepatitis C virus (HCV) patients during viral clearance is unclear and warrants investigation. Methods: A prospective study including 747 consecutive chronic hepatitis C (CHC) patients, of whom 546 had completed a course of anti-HCV therapy and underwent pre-, peri- and post-therapy surveys for anthropomorphic, viral, metabolic and hepatic profiles and adiponectin levels, was conducted in a tertiary care center. Results: Multivariate analyses indicated associations of sex, triglyceride levels and hepatic steatosis with adiponectin levels and of triglyceride levels and interferon λ3 (IFNL3) genotype with homeostasis model assessment-estimated insulin resistance (HOMA-IR) levels before anti-HCV therapy. In patients with a sustained virological response (SVR; n = 455), at 24 weeks post-therapy, sex, BMI, aspartate aminotransferase to platelet ratio index (APRI), HOMA-IR and steatosis were associated with adiponectin levels, and IFNL3 genotype was associated with HOMA-IR levels. GEE analysis demonstrated that SVR affected longitudinal trends in adiponectin levels. Compared with pre-therapy levels, adiponectin and APRI levels decreased 24 weeks post-therapy in SVR patients, regardless of baseline insulin resistance (IR). However, HOMA-IR levels decreased in SVR patients with baseline IR but increased in those without baseline IR. Compared with controls, immunohistochemical studies showed that pre-therapy CHC patients had higher hepatic adiponectin expression associated with hepatic fibrosis. Conclusions: During HCV infection, adiponectin may affect insulin sensitivity through triglycerides. After viral clearance, adiponectin levels were directly associated with insulin sensitivity and decreased upon improved hepatic fibrosis; with a link to the IFNL3 genotype, insulin sensitivity improved only in patients with baseline IR. PMID:28267407

PI3Kγ Is Critical for Dendritic Cell-Mediated CD8+ T Cell Priming and Viral Clearance during Influenza Virus Infection

PubMed Central

Nobs, Samuel Philip; Schneider, Christoph; Heer, Alex Kaspar; Huotari, Jatta; Helenius, Ari; Kopf, Manfred

2016-01-01

Phosphoinositide-3-kinases have been shown to be involved in influenza virus pathogenesis. They are targeted directly by virus proteins and are essential for efficient viral replication in infected lung epithelial cells. However, to date the role of PI3K signaling in influenza infection in vivo has not been thoroughly addressed. Here we show that one of the PI3K subunits, p110γ, is in fact critically required for mediating the host’s antiviral response. PI3Kγ deficient animals exhibit a delayed viral clearance and increased morbidity during respiratory infection with influenza virus. We demonstrate that p110γ is required for the generation and maintenance of potent antiviral CD8+ T cell responses through the developmental regulation of pulmonary cross-presenting CD103+ dendritic cells under homeostatic and inflammatory conditions. The defect in lung dendritic cells leads to deficient CD8+ T cell priming, which is associated with higher viral titers and more severe disease course during the infection. We thus identify PI3Kγ as a novel key host protective factor in influenza virus infection and shed light on an unappreciated layer of complexity concerning the role of PI3K signaling in this context. PMID:27030971

Novel mechanism of antibodies to hepatitis B virus in blocking viral particle release from cells.

PubMed

Neumann, Avidan U; Phillips, Sandra; Levine, Idit; Ijaz, Samreen; Dahari, Harel; Eren, Rachel; Dagan, Shlomo; Naoumov, Nikolai V

2010-09-01

Antibodies are thought to exert antiviral activities by blocking viral entry into cells and/or accelerating viral clearance from circulation. In particular, antibodies to hepatitis B virus (HBV) surface antigen (HBsAg) confer protection, by binding circulating virus. Here, we used mathematical modeling to gain information about viral dynamics during and after single or multiple infusions of a combination of two human monoclonal anti-HBs (HepeX-B) antibodies in patients with chronic hepatitis B. The antibody HBV-17 recognizes a conformational epitope, whereas antibody HBV-19 recognizes a linear epitope on the HBsAg. The kinetic profiles of the decline of serum HBV DNA and HBsAg revealed partial blocking of virion release from infected cells as a new antiviral mechanism, in addition to acceleration of HBV clearance from the circulation. We then replicated this approach in vitro, using cells secreting HBsAg, and compared the prediction of the mathematical modeling obtained from the in vivo kinetics. In vitro, HepeX-B treatment of HBsAg-producing cells showed cellular uptake of antibodies, resulting in intracellular accumulation of viral particles. Blocking of HBsAg secretion also continued after HepeX-B was removed from the cell culture supernatants. These results identify a novel antiviral mechanism of antibodies to HBsAg (anti-HBs) involving prolonged blocking of the HBV and HBsAg subviral particles release from infected cells. This may have implications in designing new therapies for patients with chronic HBV infection and may also be relevant in other viral infections.

Alum Adjuvant Enhances Protection against Respiratory Syncytial Virus but Exacerbates Pulmonary Inflammation by Modulating Multiple Innate and Adaptive Immune Cells

PubMed Central

Kim, Ki-Hye; Lee, Young-Tae; Hwang, Hye Suk; Kwon, Young-Man; Jung, Yu-Jin; Lee, Youri; Lee, Jong Seok; Lee, Yu-Na; Park, Soojin; Kang, Sang-Moo

2015-01-01

Respiratory syncytial virus (RSV) is well-known for inducing vaccine-enhanced respiratory disease after vaccination of young children with formalin-inactivated RSV (FI-RSV) in alum formulation. Here, we investigated alum adjuvant effects on protection and disease after FI-RSV immunization with or without alum in comparison with live RSV reinfections. Despite viral clearance, live RSV reinfections caused weight loss and substantial pulmonary inflammation probably due to high levels of RSV specific IFN-γ+IL4-, IFN-γ-TNF-α+, IFN-γ+TNF-α- effector CD4 and CD8 T cells. Alum adjuvant significantly improved protection as evidenced by effective viral clearance compared to unadjuvanted FI-RSV. However, in contrast to unadjuvanted FI-RSV, alum-adjuvanted FI-RSV (FI-RSV-A) induced severe vaccine-enhanced RSV disease including weight loss, eosinophilia, and lung histopathology. Alum adjuvant in the FI-RSV-A was found to be mainly responsible for inducing high levels of RSV-specific IFN-γ-IL4+, IFN-γ-TNF-α+ CD4+ T cells, and proinflammatory cytokines IL-6 and IL-4 as well as B220+ plasmacytoid and CD4+ dendritic cells, and inhibiting the induction of IFN-γ+CD8 T cells. This study suggests that alum adjuvant in FI-RSV vaccines increases immunogenicity and viral clearance but also induces atypical T helper CD4+ T cells and multiple inflammatory dendritic cell subsets responsible for vaccine-enhanced severe RSV disease. PMID:26468884

NK T Cells Contribute to Expansion of CD8+ T Cells and Amplification of Antiviral Immune Responses to Respiratory Syncytial Virus

PubMed Central

Johnson, Teresa R.; Hong, Seokmann; Van Kaer, Luc; Koezuka, Yasuhiko; Graham, Barney S.

2002-01-01

CD1d-deficient mice have normal numbers of T lymphocytes and natural killer cells but lack Vα14+ natural killer T cells. Respiratory syncytial virus (RSV) immunopathogenesis was evaluated in 129×C57BL/6, C57BL/6, and BALB/c CD1d−/− mice. CD8+ T lymphocytes were reduced in CD1d−/− mice of all strains, as shown by cell surface staining and major histocompatibility complex class I tetramer analysis, and resulted in strain-specific alterations in illness, viral clearance, and gamma interferon (IFN-γ) production. Transient activation of NK T cells in CD1d+/+ mice by α-GalCer resulted in reduced illness and delayed viral clearance. These data suggest that early IFN-γ production and efficient induction of CD8+-T-cell responses during primary RSV infection require CD1d-dependent events. We also tested the ability of α-GalCer as an adjuvant to modulate the type 2 immune responses induced by RSV glycoprotein G or formalin-inactivated RSV immunization. However, immunized CD1-deficient or α-GalCer-treated wild-type mice did not exhibit diminished disease following RSV challenge. Rather, some disease parameters, including cytokine production, eosinophilia, and viral clearance, were increased. These findings indicate that CD1d-dependent NK T cells play a role in expansion of CD8+ T cells and amplification of antiviral responses to RSV. PMID:11932395

Characterizing the impact of pressure on virus filtration processes and establishing design spaces to ensure effective parvovirus removal.

PubMed

Strauss, Daniel; Goldstein, Joshua; Hongo-Hirasaki, Tomoko; Yokoyama, Yoshiro; Hirotomi, Naokatsu; Miyabayashi, Tomoyuki; Vacante, Dominick

2017-09-01

Virus filtration provides robust removal of potential viral contaminants and is a critical step during the manufacture of biotherapeutic products. However, recent studies have shown that small virus removal can be impacted by low operating pressure and depressurization. To better understand the impact of these conditions and to define robust virus filtration design spaces, we conducted multivariate analyses to evaluate parvovirus removal over wide ranges of operating pressure, solution pH, and conductivity for three mAb products on Planova™ BioEX and 20N filters. Pressure ranges from 0.69 to 3.43 bar (10.0-49.7 psi) for Planova BioEX filters and from 0.50 to 1.10 bar (7.3 to 16.0 psi) for Planova 20N filters were identified as ranges over which effective removal of parvovirus is achieved for different products over wide ranges of pH and conductivity. Viral clearance at operating pressure below the robust pressure range suggests that effective parvovirus removal can be achieved at low pressure but that Minute virus of mice (MVM) logarithmic reduction value (LRV) results may be impacted by product and solution conditions. These results establish robust design spaces for Planova BioEX and 20N filters where high parvovirus clearance can be expected for most antibody products and provide further understanding of viral clearance mechanisms. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1294-1302, 2017. © 2017 American Institute of Chemical Engineers.

Viral Inhibition of PRR-Mediated Innate Immune Response: Learning from KSHV Evasion Strategies.

PubMed

Lee, Hye-Ra; Choi, Un Yung; Hwang, Sung-Woo; Kim, Stephanie; Jung, Jae U

2016-11-30

The innate immune system has evolved to detect and destroy invading pathogens before they can establish systemic infection. To successfully eradicate pathogens, including viruses, host innate immunity is activated through diverse pattern recognition receptors (PRRs) which detect conserved viral signatures and trigger the production of type I interferon (IFN) and pro-inflammatory cytokines to mediate viral clearance. Viral persistence requires that viruses co-opt cellular pathways and activities for their benefit. In particular, due to the potent antiviral activities of IFN and cytokines, viruses have developed various strategies to meticulously modulate intracellular innate immune sensing mechanisms to facilitate efficient viral replication and persistence. In this review, we highlight recent advances in the study of viral immune evasion strategies with a specific focus on how Kaposi's sarcoma-associated herpesvirus (KSHV) effectively targets host PRR signaling pathways.

Ebola (Ebola Virus Disease): Q&As on Transmission

MedlinePlus

... Response Planning Tips Managing and Preventing Cases of Malaria in Areas with Ebola Phone Numbers for State ... the Ebola outbreak due to the risk of malaria. In addition, plasma derived products have viral clearance ...

Interferon Lambda 4 Genotype Is Associated With Jaundice and Elevated Aminotransferase Levels During Acute Hepatitis C Virus Infection: Findings From the InC3 Collaborative.

PubMed

Page, Kimberly; Mirzazadeh, Ali; Rice, Thomas M; Grebely, Jason; Kim, Arthur Y; Cox, Andrea L; Morris, Meghan D; Hellard, Margaret; Bruneau, Julie; Shoukry, Naglaa H; Dore, Gregory J; Maher, Lisa; Lloyd, Andrew R; Lauer, Georg; Prins, Maria; McGovern, Barbara H

2016-01-01

Symptomatic acute HCV infection and interferon lambda 4 (IFNL4) genotypes are important predictors of spontaneous viral clearance. Using data from a multicohort database (Injecting Cohorts [InC3] Collaborative), we establish an independent association between host IFNL4 genotype and symptoms of acute hepatitis C virus infection. This association potentially explains the higher spontaneous clearance observed in some patients with symptomatic disease.

Interferon Lambda 4 Genotype Is Associated With Jaundice and Elevated Aminotransferase Levels During Acute Hepatitis C Virus Infection: Findings From the InC3 Collaborative

PubMed Central

Page, Kimberly; Mirzazadeh, Ali; Rice, Thomas M.; Grebely, Jason; Kim, Arthur Y.; Cox, Andrea L.; Morris, Meghan D.; Hellard, Margaret; Bruneau, Julie; Shoukry, Naglaa H.; Dore, Gregory J.; Maher, Lisa; Lloyd, Andrew R.; Lauer, Georg; Prins, Maria; McGovern, Barbara H.

2016-01-01

Symptomatic acute HCV infection and interferon lambda 4 (IFNL4) genotypes are important predictors of spontaneous viral clearance. Using data from a multicohort database (Injecting Cohorts [InC3] Collaborative), we establish an independent association between host IFNL4 genotype and symptoms of acute hepatitis C virus infection. This association potentially explains the higher spontaneous clearance observed in some patients with symptomatic disease. PMID:26973850

The West Nile Virus-Like Flavivirus Koutango Is Highly Virulent in Mice due to Delayed Viral Clearance and the Induction of a Poor Neutralizing Antibody Response

PubMed Central

Setoh, Yin X.; Biron, Rebecca M.; Sester, David P.; Kim, Kwang Sik; Hobson-Peters, Jody; Hall, Roy A.; Bielefeldt-Ohmann, Helle

2014-01-01

ABSTRACT The mosquito-borne West Nile virus (WNV) is responsible for outbreaks of viral encephalitis in humans, horses, and birds, with particularly virulent strains causing recent outbreaks of disease in eastern Europe, the Middle East, North America, and Australia. Previous studies have phylogenetically separated WNV strains into two main genetic lineages (I and II) containing virulent strains associated with neurological disease. Several WNV-like strains clustering outside these lineages have been identified and form an additional five proposed lineages. However, little is known about whether these strains have the potential to induce disease. In a comparative analysis with the highly virulent lineage I American strain (WNVNY99), the low-pathogenicity lineage II strain (B956), a benign Australian strain, Kunjin (WNVKUN), the African WNV-like Koutango virus (WNVKOU), and a WNV-like isolate from Sarawak, Malaysia (WNVSarawak), were assessed for neuroinvasive properties in a murine model and for their replication kinetics in vitro. While WNVNY99 replicated to the highest levels in vitro, in vivo mouse challenge revealed that WNVKOU was more virulent, with a shorter time to onset of neurological disease and higher morbidity. Histological analysis of WNVKOU- and WNVNY99-infected brain and spinal cords demonstrated more prominent meningoencephalitis and the presence of viral antigen in WNVKOU-infected mice. Enhanced virulence of WNVKOU also was associated with poor viral clearance in the periphery (sera and spleen), a skewed innate immune response, and poor neutralizing antibody development. These data demonstrate, for the first time, potent neuroinvasive and neurovirulent properties of a WNV-like virus outside lineages I and II. IMPORTANCE In this study, we characterized the in vitro and in vivo properties of previously uncharacterized West Nile virus strains and West Nile-like viruses. We identified a West Nile-like virus, Koutango virus (WNVKOU), that was more virulent than a known virulent lineage I virus, WNVNY99. The enhanced virulence of WNVKOU was associated with poor viral clearance and the induction of a poor neutralizing antibody response. These findings provide new insights into the pathogenesis of West Nile virus. PMID:24942584

Struggle for space: viral extinction through competition for cells.

PubMed

Cuesta, José A; Aguirre, Jacobo; Capitán, José A; Manrubia, Susanna C

2011-01-14

The design of protocols to suppress the propagation of viral infections is an enduring enterprise, especially hindered by limited knowledge of the mechanisms leading to viral extinction. Here we report on infection extinction due to intraspecific competition to infect susceptible hosts. Beneficial mutations increase the production of viral progeny, while the host cell may develop defenses against infection. For an unlimited number of host cells, a feedback runaway coevolution between host resistance and progeny production occurs. However, physical space limits the advantage that the virus obtains from increasing offspring numbers; thus, infection clearance may result from an increase in host defenses beyond a finite threshold. Our results might be relevant to devise improved control strategies in environments with mobility constraints or different geometrical properties.

Germ Line IgM Is Sufficient, but Not Required, for Antibody-Mediated Alphavirus Clearance from the Central Nervous System.

PubMed

Nilaratanakul, Voraphoj; Chen, Jie; Tran, Oanh; Baxter, Victoria K; Troisi, Elizabeth M; Yeh, Jane X; Griffin, Diane E

2018-04-01

Sindbis virus (SINV) infection of neurons in the brain and spinal cord in mice provides a model system for investigating recovery from encephalomyelitis and antibody-mediated clearance of virus from the central nervous system (CNS). To determine the roles of IgM and IgG in recovery, we compared the responses of immunoglobulin-deficient activation-induced adenosine deaminase-deficient (AID -/- ), secretory IgM-deficient (sIgM -/- ), and AID -/- sIgM -/- double-knockout (DKO) mice with those of wild-type (WT) C57BL/6 mice for disease, clearance of infectious virus and viral RNA from brain and spinal cord, antibody responses, and B cell infiltration into the CNS. Because AID is essential for immunoglobulin class switch recombination and somatic hypermutation, AID -/- mice produce only germ line IgM, while sIgM -/- mice secrete IgG but no IgM and DKO mice produce no secreted immunoglobulin. After intracerebral infection with the TE strain of SINV, most mice recovered. Development of neurologic disease occurred slightly later in sIgM -/- mice, but disease severity, weight loss, and survival were similar between the groups. AID -/- mice produced high levels of SINV-specific IgM, while sIgM -/- mice produced no IgM and high levels of IgG2a compared to WT mice. All mice cleared infectious virus from the spinal cord, but DKO mice failed to clear infectious virus from brain and had higher levels of viral RNA in the CNS late after infection. The numbers of infected cells and the amount of cell death in brain were comparable. We conclude that antibody is required and that either germ line IgM or IgG is sufficient for clearance of virus from the CNS. IMPORTANCE Mosquito-borne alphaviruses that infect neurons can cause fatal encephalomyelitis. Recovery requires a mechanism for the immune system to clear virus from infected neurons without harming the infected cells. Antiviral antibody has previously been shown to be a noncytolytic means for alphavirus clearance. Antibody-secreting cells enter the nervous system after infection and produce antiviral IgM before IgG. Clinical studies of human viral encephalomyelitis suggest that prompt production of IgM is associated with recovery, but it was not known whether IgM is effective for clearance. Our studies used mice deficient in production of IgM, IgG, or both to characterize the antibody necessary for alphavirus clearance. All mice developed similar signs of neurologic disease and recovered from infection. Antibody was necessary for virus clearance from the brain, and either early germ line IgM or IgG was sufficient. These studies support the clinical observation that prompt production of antiviral antibody is a determinant of outcome. Copyright © 2018 American Society for Microbiology.

Understanding the causes and consequences of measles virus persistence

PubMed Central

Griffin, Diane E.; Lin, Wen-Hsuan W.; Nelson, Ashley N.

2018-01-01

Measles is an acute systemic viral disease with initial amplification of infection in lymphoid tissue and subsequent spread over 10–14 days to multiple organs. Failure of the innate response to control initial measles virus (MeV) replication is associated with the ability of MeV to inhibit the induction of type I interferon and interferon-stimulated antiviral genes. Rather, the innate response is characterized by the expression of proteins regulated by nuclear factor kappa B and the inflammasome. With eventual development of the adaptive response, the rash appears with immune cell infiltration into sites of virus replication to initiate the clearance of infectious virus. However, MeV RNA is cleared much more slowly than recoverable infectious virus and remains present in lymphoid tissue for at least 6 months after infection. Persistence of viral RNA and protein suggests persistent low-level replication in lymphoid tissue that may facilitate maturation of the immune response, resulting in lifelong protection from reinfection, while persistence in other tissues (for example, the nervous system) may predispose to development of late disease such as subacute sclerosing panencephalitis. Further studies are needed to identify mechanisms of viral clearance and to understand the relationship between persistence and development of lifelong immunity. PMID:29560260

Understanding the causes and consequences of measles virus persistence.

PubMed

Griffin, Diane E; Lin, Wen-Hsuan W; Nelson, Ashley N

2018-01-01

Measles is an acute systemic viral disease with initial amplification of infection in lymphoid tissue and subsequent spread over 10-14 days to multiple organs. Failure of the innate response to control initial measles virus (MeV) replication is associated with the ability of MeV to inhibit the induction of type I interferon and interferon-stimulated antiviral genes. Rather, the innate response is characterized by the expression of proteins regulated by nuclear factor kappa B and the inflammasome. With eventual development of the adaptive response, the rash appears with immune cell infiltration into sites of virus replication to initiate the clearance of infectious virus. However, MeV RNA is cleared much more slowly than recoverable infectious virus and remains present in lymphoid tissue for at least 6 months after infection. Persistence of viral RNA and protein suggests persistent low-level replication in lymphoid tissue that may facilitate maturation of the immune response, resulting in lifelong protection from reinfection, while persistence in other tissues (for example, the nervous system) may predispose to development of late disease such as subacute sclerosing panencephalitis. Further studies are needed to identify mechanisms of viral clearance and to understand the relationship between persistence and development of lifelong immunity.

Foot clearance and variability in mono- and multifocal intraocular lens users during stair navigation.

PubMed

Renz, Erik; Hackney, Madeleine; Hall, Courtney

2016-01-01

Intraocular lenses (IOLs) provide distance and near refraction and are becoming the standard for cataract surgery. Multifocal glasses increase variability of toe clearance in older adults navigating stairs and increase fall risk; however, little is known about the biomechanics of stair navigation in individuals with multifocal IOLs. This study compared clearance while ascending and descending stairs in individuals with monofocal versus multifocal IOLs. Eight participants with multifocal IOLs (4 men, 4 women; mean age = 66.5 yr, standard deviation [SD] = 6.26) and fifteen male participants with monofocal IOLs (mean age = 69.9 yr, SD = 6.9) underwent vision and mobility testing. Motion analysis recorded kinematic and custom software-calculated clearances in three-dimensional space. No significant differences were found between groups on minimum clearance or variability. Clearance differed for ascending versus descending stairs: the first step onto the stair had the greatest toe clearance during ascent, whereas the final step to the floor had the greatest heel clearance during descent. This preliminary study indicates that multifocal IOLs have similar biomechanic characteristics to monofocal IOLs. Given that step characteristics are related to fall risk, we can tentatively speculate that multifocal IOLs may carry no additional fall risk.

Differentially regulated gene expression associated with hepatitis C virus clearance.

PubMed

Grimes, Carolyn Z; Hwang, Lu-Yu; Wei, Peng; Shah, Dimpy P; Volcik, Kelly A; Brown, Eric L

2013-03-01

Human chronic hepatitis C virus (HCV) infections pose a significant public health threat, necessitating the development of novel treatments and vaccines. HCV infections range from spontaneous resolution to end-stage liver disease. Approximately 10-30% of HCV infections undergo spontaneous resolution independent of treatment by yet-to-be-defined mechanisms. These individuals test positive for anti-HCV antibodies in the absence of detectable viral serum RNA. To identify genes associated with HCV clearance, this study compared gene expression profiles between current drug users chronically infected with HCV and drug users who cleared their HCV infection. This analysis identified 91 differentially regulated (up- or downregulated by twofold or more) genes potentially associated with HCV clearance. The majority of genes identified were associated with immune function, with the remaining genes categorized either as cancer related or 'other'. Identification of factors and pathways that may influence virus clearance will be essential to the development of novel treatment strategies.

Myxovirus resistance 1 gene polymorphisms and outcomes of viral hepatitis B and C infections in Moroccan patients.

PubMed

Rebbani, Khadija; Ababou, Mostafa; Nadifi, Sellama; Kandil, Mostafa; Marchio, Agnès; Pineau, Pascal; Ezzikouri, Sayeh; Benjelloun, Soumaya

2017-04-01

Host genetic factors may influence the establishment of chronicity or spontaneous clearance in viral hepatitis B and C infections. More light was shed on the role played by interferon-stimulated genes in the innate immunity. Myxovirus resistance 1 (MX1) is one of those key genes that have reported to inhibit several viruses. The present study aims to explore the possible association of -88G/T and -123C/A promoter variants of MX1 with susceptibility to chronic hepatitis B and C and/or with spontaneous clearance in a Moroccan population. The -88G/T and -123C/A SNPs were genotyped by PCR-RFLP in 538 individuals stratified into HBV chronically infected patients (n = 120), HCV-chronically infected patients (n = 115), HBV spontaneously resolved subjects (n = 114), HCV spontaneously resolved group (n = 52), and healthy controls (n = 137). A significant association of -123C allele with HBV spontaneous clearance has been found (P = 0.002, OR = 2.34; 95%CI [1.36-4]). In addition, a significant correlation between the MX1-GC haplotype and HBV spontaneous clearance (P < 0.001) was found. No significant association of -88G/T and -123C/A polymorphisms with regard to HCV infection was observed in this study. Here, we show that for North African patients with chronic hepatitis, MX1 gene variation at position -123 may influence the outcome of HBV infection but not HCV infection. J. Med. Virol. 89:647-652, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Dynamics of viral load in Crimean Congo hemorrhagic fever.

PubMed

Hasanoglu, Imran; Guner, Rahmet; Carhan, Ahmet; K Tufan, Zeliha; Y Caglayik, Dilek; Yilmaz, Gul R; Tasyaran, Mehmet A

2018-04-01

Crimean Congo hemorrhagic fever (CCHF) is a viral zoonotic disease with high mortality rate. There are only a few studies on viral load in CCHF. In our study, we revealed the dynamics of viral load and its relationship with mortality in early phase of the disease. A total of 138 serum samples were collected from 23 patients. All patients had positive PCR for CCHF on admission. Serum samples were obtained daily from all patients for the first 6 days of hospitalization and stored at -80°C for viral load measurement. We found statistically significant difference between mean number of viremic serum samples of fatal and non-fatal patients. Furthermore, non-fatal cases' viral loads demonstrated statistically significant decreases over time; however, we could not observe a similar trend in viral loads of fatal cases. Limited number of studies on CCHF indicate that score of the contest between CCHF virus and immune system determines the survival in CCHF and viral load is found to be the most prognostic factor. In our study, we found that there is a notable decrease trend in viral loads of non-fatal patients over time and this clearance of CCHF virus is significantly related with survival. © 2017 Wiley Periodicals, Inc.

Hepatitis C virus dynamics and cellular gene expression in uPA-SCID chimeric mice with humanized livers during intravenous silibinin monotherapy

DOE PAGES

DebRoy, Swati; Hiraga, Nobuhiko; Imamura, Michio; ...

2016-06-08

Legalon SIL (SIL) is a chemically hydrophilized version of silibinin, an extract of milk thistle ( Silybum marianum) seeds that has exhibited hepatoprotective and antiviral effectiveness against hepatitis C virus (HCV) in patients leading to viral clearance in combination with ribavirin. In this paper, to elucidate the incompletely understood mode of action of SIL against HCV, mathematical modelling of HCV kinetics and human hepatocyte gene expression studies were performed in uPA-SCID-chimeric mice with humanized livers. Chronically HCV-infected mice (n = 15) were treated for 14 days with daily intravenous SIL at 469, 265 or 61.5 mg/kg. Serum HCV and humanmore » albumin (hAlb) were measured frequently, and liver HCV RNA was analysed at days 3 and 14. Microarray analysis of human hepatocyte gene expression was performed at days 0, 3 and 14 of treatment. While hAlb remained constant, a biphasic viral decline in serum was observed consisting of a rapid 1st phase followed by a second slower phase (or plateau with the two lower SIL dosings). SIL effectiveness in blocking viral production was similar among dosing groups (median ε = 77%). However, the rate of HCV-infected hepatocyte decline, δ, was dose-dependent. Intracellular HCV RNA levels correlated (r = 0.66, P = 0.01) with serum HCV RNA. Pathway analysis revealed increased anti-inflammatory and antiproliferative gene expression in human hepatocytes in SIL-treated mice. Finally, the results suggest that SIL could lead to a continuous second-phase viral decline, that is potentially viral clearance, in the absence of adaptive immune response along with increased anti-inflammatory and antiproliferative gene expression in human hepatocytes.« less

Hepatitis C virus dynamics and cellular gene expression in uPA-SCID chimeric mice with humanized livers during intravenous silibinin monotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

DebRoy, Swati; Hiraga, Nobuhiko; Imamura, Michio

Legalon SIL (SIL) is a chemically hydrophilized version of silibinin, an extract of milk thistle ( Silybum marianum) seeds that has exhibited hepatoprotective and antiviral effectiveness against hepatitis C virus (HCV) in patients leading to viral clearance in combination with ribavirin. In this paper, to elucidate the incompletely understood mode of action of SIL against HCV, mathematical modelling of HCV kinetics and human hepatocyte gene expression studies were performed in uPA-SCID-chimeric mice with humanized livers. Chronically HCV-infected mice (n = 15) were treated for 14 days with daily intravenous SIL at 469, 265 or 61.5 mg/kg. Serum HCV and humanmore » albumin (hAlb) were measured frequently, and liver HCV RNA was analysed at days 3 and 14. Microarray analysis of human hepatocyte gene expression was performed at days 0, 3 and 14 of treatment. While hAlb remained constant, a biphasic viral decline in serum was observed consisting of a rapid 1st phase followed by a second slower phase (or plateau with the two lower SIL dosings). SIL effectiveness in blocking viral production was similar among dosing groups (median ε = 77%). However, the rate of HCV-infected hepatocyte decline, δ, was dose-dependent. Intracellular HCV RNA levels correlated (r = 0.66, P = 0.01) with serum HCV RNA. Pathway analysis revealed increased anti-inflammatory and antiproliferative gene expression in human hepatocytes in SIL-treated mice. Finally, the results suggest that SIL could lead to a continuous second-phase viral decline, that is potentially viral clearance, in the absence of adaptive immune response along with increased anti-inflammatory and antiproliferative gene expression in human hepatocytes.« less

Modeling how reversal of immune exhaustion elicits cure of chronic hepatitis C after the end of treatment with direct-acting antiviral agents.

PubMed

Baral, Subhasish; Roy, Rahul; Dixit, Narendra M

2018-05-09

A fraction of chronic hepatitis C patients treated with direct-acting antivirals (DAAs) achieved sustained virological responses (SVR), or cure, despite having detectable viremia at the end of treatment (EOT). This observation, termed EOT + /SVR, remains puzzling and precludes rational optimization of treatment durations. One hypothesis to explain EOT + /SVR, the immunologic hypothesis, argues that the viral decline induced by DAAs during treatment reverses the exhaustion of cytotoxic T lymphocytes (CTLs), which then clear the infection after treatment. Whether the hypothesis is consistent with data of viral load changes in patients who experienced EOT + /SVR is unknown. Here, we constructed a mathematical model of viral kinetics incorporating the immunologic hypothesis and compared its predictions with patient data. We found the predictions to be in quantitative agreement with patient data. Using the model, we unraveled an underlying bistability that gives rise to EOT + /SVR and presents a new avenue to optimize treatment durations. Infected cells trigger both activation and exhaustion of CTLs. CTLs in turn kill infected cells. Due to these competing interactions, two stable steady states, chronic infection and viral clearance, emerge, separated by an unstable steady state with intermediate viremia. When treatment during chronic infection drives viremia sufficiently below the unstable state, spontaneous viral clearance results post-treatment, marking EOT + /SVR. The duration to achieve this desired reduction in viremia defines the minimum treatment duration required for ensuring SVR, which our model can quantify. Estimating parameters defining the CTL response of individuals to HCV infection would enable the application of our model to personalize treatment durations. © 2018 The Authors Immunology & Cell Biology published by John Wiley & Sons Australia, Ltd on behalf of Australasian Society for Immunology Inc.

Acute hepatitis A virus infection is associated with a limited type I interferon response and persistence of intrahepatic viral RNA.

PubMed

Lanford, Robert E; Feng, Zongdi; Chavez, Deborah; Guerra, Bernadette; Brasky, Kathleen M; Zhou, Yan; Yamane, Daisuke; Perelson, Alan S; Walker, Christopher M; Lemon, Stanley M

2011-07-05

Hepatitis A virus (HAV) is an hepatotropic human picornavirus that is associated only with acute infection. Its pathogenesis is not well understood because there are few studies in animal models using modern methodologies. We characterized HAV infections in three chimpanzees, quantifying viral RNA by quantitative RT-PCR and examining critical aspects of the innate immune response including intrahepatic IFN-stimulated gene expression. We compared these infection profiles with similar studies of chimpanzees infected with hepatitis C virus (HCV), an hepatotropic flavivirus that frequently causes persistent infection. Surprisingly, HAV-infected animals exhibited very limited induction of type I IFN-stimulated genes in the liver compared with chimpanzees with acute resolving HCV infection, despite similar levels of viremia and 100-fold greater quantities of viral RNA in the liver. Minimal IFN-stimulated gene 15 and IFIT1 responses peaked 1-2 wk after HAV challenge and then subsided despite continuing high hepatic viral RNA. An acute inflammatory response at 3-4 wk correlated with the appearance of virus-specific antibodies and apoptosis and proliferation of hepatocytes. Despite this, HAV RNA persisted in the liver for months, remaining present long after clearance from serum and feces and revealing dramatic differences in the kinetics of clearance in the three compartments. Viral RNA was detected in the liver for significantly longer (35 to >48 wk) than HCV RNA in animals with acute resolving HCV infection (10-20 wk). Collectively, these findings indicate that HAV is far stealthier than HCV early in the course of acute resolving infection. HAV infections represent a distinctly different paradigm in virus-host interactions within the liver.

The Viral Transcription Group Determines the HLA Class I Cellular Immune Response Against Human Respiratory Syncytial Virus*

PubMed Central

Johnstone, Carolina; Lorente, Elena; Barriga, Alejandro; Barnea, Eilon; Infantes, Susana; Lemonnier, François A.; David, Chella S.; Admon, Arie; López, Daniel

2015-01-01

The cytotoxic T-lymphocyte-mediated killing of virus-infected cells requires previous recognition of short viral antigenic peptides bound to human leukocyte antigen class I molecules that are exposed on the surface of infected cells. The cytotoxic T-lymphocyte response is critical for the clearance of human respiratory syncytial virus infection. In this study, naturally processed viral human leukocyte antigen class I ligands were identified with mass spectrometry analysis of complex human leukocyte antigen-bound peptide pools isolated from large amounts of human respiratory syncytial virus-infected cells. Acute antiviral T-cell response characterization showed that viral transcription determines both the immunoprevalence and immunodominance of the human leukocyte antigen class I response to human respiratory syncytial virus. These findings have clear implications for antiviral vaccine design. PMID:25635267

Adverse events post smallpox-vaccination: insights from tail scarification infection in mice with Vaccinia virus.

PubMed

Mota, Bruno E F; Gallardo-Romero, Nadia; Trindade, Giliane; Keckler, M Shannon; Karem, Kevin; Carroll, Darin; Campos, Marco A; Vieira, Leda Q; da Fonseca, Flávio G; Ferreira, Paulo C P; Bonjardim, Cláudio A; Damon, Inger K; Kroon, Erna G

2011-04-15

Adverse events upon smallpox vaccination with fully-replicative strains of Vaccinia virus (VACV) comprise an array of clinical manifestations that occur primarily in immunocompromised patients leading to significant host morbidity/mortality. The expansion of immune-suppressed populations and the possible release of Variola virus as a bioterrorist act have given rise to concerns over vaccination complications should more widespread vaccination be reinitiated. Our goal was to evaluate the components of the host immune system that are sufficient to prevent morbidity/mortality in a murine model of tail scarification, which mimics immunological and clinical features of smallpox vaccination in humans. Infection of C57BL/6 wild-type mice led to a strictly localized infection, with complete viral clearance by day 28 p.i. On the other hand, infection of T and B-cell deficient mice (Rag1(-/-)) produced a severe disease, with uncontrolled viral replication at the inoculation site and dissemination to internal organs. Infection of B-cell deficient animals (µMT) produced no mortality. However, viral clearance in µMT animals was delayed compared to WT animals, with detectable viral titers in tail and internal organs late in infection. Treatment of Rag1(-/-) with rabbit hyperimmune anti-vaccinia serum had a subtle effect on the morbidity/mortality of this strain, but it was effective in reduce viral titers in ovaries. Finally, NUDE athymic mice showed a similar outcome of infection as Rag1(-/-), and passive transfer of WT T cells to Rag1(-/-) animals proved fully effective in preventing morbidity/mortality. These results strongly suggest that both T and B cells are important in the immune response to primary VACV infection in mice, and that T-cells are required to control the infection at the inoculation site and providing help for B-cells to produce antibodies, which help to prevent viral dissemination. These insights might prove helpful to better identify individuals with higher risk of complications after infection with poxvirus.

Statistical Linkage Analysis of Substitutions in Patient-Derived Sequences of Genotype 1a Hepatitis C Virus Nonstructural Protein 3 Exposes Targets for Immunogen Design

PubMed Central

Quadeer, Ahmed A.; Louie, Raymond H. Y.; Shekhar, Karthik; Chakraborty, Arup K.; Hsing, I-Ming

2014-01-01

ABSTRACT Chronic hepatitis C virus (HCV) infection is one of the leading causes of liver failure and liver cancer, affecting around 3% of the world's population. The extreme sequence variability of the virus resulting from error-prone replication has thwarted the discovery of a universal prophylactic vaccine. It is known that vigorous and multispecific cellular immune responses, involving both helper CD4+ and cytotoxic CD8+ T cells, are associated with the spontaneous clearance of acute HCV infection. Escape mutations in viral epitopes can, however, abrogate protective T-cell responses, leading to viral persistence and associated pathologies. Despite the propensity of the virus to mutate, there might still exist substitutions that incur a fitness cost. In this paper, we identify groups of coevolving residues within HCV nonstructural protein 3 (NS3) by analyzing diverse sequences of this protein using ideas from random matrix theory and associated methods. Our analyses indicate that one of these groups comprises a large percentage of residues for which HCV appears to resist multiple simultaneous substitutions. Targeting multiple residues in this group through vaccine-induced immune responses should either lead to viral recognition or elicit escape substitutions that compromise viral fitness. Our predictions are supported by published clinical data, which suggested that immune genotypes associated with spontaneous clearance of HCV preferentially recognized and targeted this vulnerable group of residues. Moreover, mapping the sites of this group onto the available protein structure provided insight into its functional significance. An epitope-based immunogen is proposed as an alternative to the NS3 epitopes in the peptide-based vaccine IC41. IMPORTANCE Despite much experimental work on HCV, a thorough statistical study of the HCV sequences for the purpose of immunogen design was missing in the literature. Such a study is vital to identify epistatic couplings among residues that can provide useful insights for designing a potent vaccine. In this work, ideas from random matrix theory were applied to characterize the statistics of substitutions within the diverse publicly available sequences of the genotype 1a HCV NS3 protein, leading to a group of sites for which HCV appears to resist simultaneous substitutions possibly due to deleterious effect on viral fitness. Our analysis leads to completely novel immunogen designs for HCV. In addition, the NS3 epitopes used in the recently proposed peptide-based vaccine IC41 were analyzed in the context of our framework. Our analysis predicts that alternative NS3 epitopes may be worth exploring as they might be more efficacious. PMID:24760894

Should we consider steps with variable height for a safer stair negotiation in older adults?

PubMed

Kunzler, Marcos R; da Rocha, Emmanuel S; Dos Santos, Christielen S; Ceccon, Fernando G; Priario, Liver A; Carpes, Felipe P

2018-01-01

Effects of exercise on foot clearances are important. In older adults variations in foot clearances during walking may lead to a fall, but there is a lack of information concerning stair negotiation in older adults. Whether a condition of post exercise changes foot clearances between steps of a staircase in older adults still unknown. To determine differences in clearances when older adults negotiate different steps of a staircase before and after a session of aerobic exercise. Kinematics data from 30 older adults were acquired and the toe and heel clearances were determined for each step. Clearances were compared between the steps. Smaller clearances were found at the highest step during ascending and descending, which was not changed by exercise. Smaller clearances suggest higher risk of tripping at the top of the staircase, regardless of exercise. A smaller step at the top of a short flight of stairs could reduce chances of tripping in older adults. It suggests that steps with variable height could make stair negotiation safer in older adults. This hypothesis should be tested in further studies.

Zinc is a potent and specific inhibitor of IFN-λ3 signalling

PubMed Central

Read, Scott A.; O'Connor, Kate S.; Suppiah, Vijay; Ahlenstiel, Chantelle L. E.; Obeid, Stephanie; Cook, Kristina M.; Cunningham, Anthony; Douglas, Mark W.; Hogg, Philip J.; Booth, David; George, Jacob; Ahlenstiel, Golo

2017-01-01

Lambda interferons (IFNL, IFN-λ) are pro-inflammatory cytokines important in acute and chronic viral infection. Single-nucleotide polymorphisms rs12979860 and rs8099917 within the IFNL gene locus predict hepatitis C virus (HCV) clearance, as well as inflammation and fibrosis progression in viral and non-viral liver disease. The underlying mechanism, however, is not defined. Here we show that the rs12979860 CC genotype correlates with increased hepatic metallothionein expression through increased systemic zinc levels. Zinc interferes with IFN-λ3 binding to IFNL receptor 1 (IFNLR1), resulting in decreased antiviral activity and increased viral replication (HCV, influenza) in vitro. HCV patients with high zinc levels have low hepatocyte antiviral and inflammatory gene expression and high viral loads, confirming the inhibitory role of zinc in vivo. We provide the first evidence that zinc can act as a potent and specific inhibitor of IFN-λ3 signalling and highlight its potential as a target of therapeutic intervention for IFN-λ3-mediated chronic disease. PMID:28513591

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rong, Libin; Guedj, Jeremie; Dahari, Harel

The current paradigm for studying hepatitis C virus (HCV) dynamics in patients utilizes a standard viral dynamic model that keeps track of uninfected (target) cells, infected cells, and virus. The model does not account for the dynamics of intracellular viral replication, which is the major target of direct-acting antiviral agents (DAAs). In this paper, we describe and study a recently developed multiscale age-structured model that explicitly considers the potential effects of DAAs on intracellular viral RNA production, degradation, and secretion as virus into the circulation. We show that when therapy significantly blocks both intracellular viral RNA production and virus secretion,more » the serum viral load decline has three phases, with slopes reflecting the rate of serum viral clearance, the rate of loss of intracellular viral RNA, and the rate of loss of intracellular replication templates and infected cells, respectively. We also derive analytical approximations of the multiscale model and use one of them to analyze data from patients treated for 14 days with the HCV protease inhibitor danoprevir. Analysis suggests that danoprevir significantly blocks intracellular viral production (with mean effectiveness 99.2%), enhances intracellular viral RNA degradation about 5-fold, and moderately inhibits viral secretion (with mean effectiveness 56%). Finally, the multiscale model can be used to study viral dynamics in patients treated with other DAAs and explore their mechanisms of action in treatment of hepatitis C.« less

The viral transcription group determines the HLA class I cellular immune response against human respiratory syncytial virus.

PubMed

Johnstone, Carolina; Lorente, Elena; Barriga, Alejandro; Barnea, Eilon; Infantes, Susana; Lemonnier, François A; David, Chella S; Admon, Arie; López, Daniel

2015-04-01

The cytotoxic T-lymphocyte-mediated killing of virus-infected cells requires previous recognition of short viral antigenic peptides bound to human leukocyte antigen class I molecules that are exposed on the surface of infected cells. The cytotoxic T-lymphocyte response is critical for the clearance of human respiratory syncytial virus infection. In this study, naturally processed viral human leukocyte antigen class I ligands were identified with mass spectrometry analysis of complex human leukocyte antigen-bound peptide pools isolated from large amounts of human respiratory syncytial virus-infected cells. Acute antiviral T-cell response characterization showed that viral transcription determines both the immunoprevalence and immunodominance of the human leukocyte antigen class I response to human respiratory syncytial virus. These findings have clear implications for antiviral vaccine design. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Infection-specific phosphorylation of glutamyl-prolyl tRNA synthetase induces antiviral immunity

PubMed Central

Lee, Eun-Young; Lee, Hyun-Cheol; Kim, Hyun-Kwan; Jang, Song Yee; Park, Seong-Jun; Kim, Yong-Hoon; Kim, Jong Hwan; Hwang, Jungwon; Kim, Jae-Hoon; Kim, Tae-Hwan; Arif, Abul; Kim, Seon-Young; Choi, Young-Ki; Lee, Cheolju; Lee, Chul-Ho; Jung, Jae U; Fox, Paul L; Kim, Sunghoon; Lee, Jong-Soo; Kim, Myung Hee

2016-01-01

The mammalian cytoplasmic multi-tRNA synthetase complex (MSC) is a depot system that regulates non-translational cellular functions. Here we found that the MSC component glutamyl-prolyl-tRNA synthetase (EPRS) switched its function following viral infection and exhibited potent antiviral activity. Infection-specific phosphorylation of EPRS at Ser990 induced its dissociation from the MSC, after which it was guided to the antiviral signaling pathway, where it interacted with PCBP2, a negative regulator of mitochondrial antiviral signaling protein (MAVS) that is critical for antiviral immunity. This interaction blocked PCBP2-mediated ubiquitination of MAVS and ultimately suppressed viral replication. EPRS-haploid (Eprs+/−) mice showed enhanced viremia and inflammation and delayed viral clearance. This stimulus-inducible activation of MAVS by EPRS suggests an unexpected role for the MSC as a regulator of immune responses to viral infection. PMID:27595231

Methodological uncertainty in quantitative prediction of human hepatic clearance from in vitro experimental systems.

PubMed

Hallifax, D; Houston, J B

2009-03-01

Mechanistic prediction of unbound drug clearance from human hepatic microsomes and hepatocytes correlates with in vivo clearance but is both systematically low (10 - 20 % of in vivo clearance) and highly variable, based on detailed assessments of published studies. Metabolic capacity (Vmax) of commercially available human hepatic microsomes and cryopreserved hepatocytes is log-normally distributed within wide (30 - 150-fold) ranges; Km is also log-normally distributed and effectively independent of Vmax, implying considerable variability in intrinsic clearance. Despite wide overlap, average capacity is 2 - 20-fold (dependent on P450 enzyme) greater in microsomes than hepatocytes, when both are normalised (scaled to whole liver). The in vitro ranges contrast with relatively narrow ranges of clearance among clinical studies. The high in vitro variation probably reflects unresolved phenotypical variability among liver donors and practicalities in processing of human liver into in vitro systems. A significant contribution from the latter is supported by evidence of low reproducibility (several fold) of activity in cryopreserved hepatocytes and microsomes prepared from the same cells, between separate occasions of thawing of cells from the same liver. The large uncertainty which exists in human hepatic in vitro systems appears to dominate the overall uncertainty of in vitro-in vivo extrapolation, including uncertainties within scaling, modelling and drug dependent effects. As such, any notion of quantitative prediction of clearance appears severely challenged.

Visualization of a proteasome-independent intermediate during restriction of HIV-1 by rhesus TRIM5α

PubMed Central

Campbell, Edward M.; Perez, Omar; Anderson, Jenny L.; Hope, Thomas J.

2008-01-01

TRIM5 proteins constitute a class of restriction factors that prevent host cell infection by retroviruses from different species. TRIM5α restricts retroviral infection early after viral entry, before the generation of viral reverse transcription products. However, the underlying restriction mechanism remains unclear. In this study, we show that during rhesus macaque TRIM5α (rhTRIM5α)–mediated restriction of HIV-1 infection, cytoplasmic HIV-1 viral complexes can associate with concentrations of TRIM5α protein termed cytoplasmic bodies. We observe a dynamic interaction between rhTRIM5α and cytoplasmic HIV-1 viral complexes, including the de novo formation of rhTRIM5α cytoplasmic body–like structures around viral complexes. We observe that proteasome inhibition allows HIV-1 to remain stably sequestered into large rhTRIM5α cytoplasmic bodies, preventing the clearance of HIV-1 viral complexes from the cytoplasm and revealing an intermediate in the restriction process. Furthermore, we can measure no loss of capsid protein from viral complexes arrested at this intermediate step in restriction, suggesting that any rhTRIM5α-mediated loss of capsid protein requires proteasome activity. PMID:18250195

Visualization of Arenavirus RNA Species in Individual Cells by Single-Molecule Fluorescence In Situ Hybridization Suggests a Model of Cyclical Infection and Clearance during Persistence.

PubMed

King, Benjamin R; Samacoits, Aubin; Eisenhauer, Philip L; Ziegler, Christopher M; Bruce, Emily A; Zenklusen, Daniel; Zimmer, Christophe; Mueller, Florian; Botten, Jason

2018-06-15

Lymphocytic choriomeningitis mammarenavirus (LCMV) is an enveloped, negative-strand RNA virus that causes serious disease in humans but establishes an asymptomatic, lifelong infection in reservoir rodents. Different models have been proposed to describe how arenaviruses regulate the replication and transcription of their bisegmented, single-stranded RNA genomes, particularly during persistent infection. However, these models were based largely on viral RNA profiling data derived from entire populations of cells. To better understand LCMV replication and transcription at the single-cell level, we established a high-throughput, single-molecule fluorescence in situ hybridization (smFISH) image acquisition and analysis pipeline and examined viral RNA species at discrete time points from virus entry through the late stages of persistent infection in vitro We observed the transcription of viral nucleoprotein and polymerase mRNAs from the incoming S and L segment genomic RNAs, respectively, within 1 h of infection, whereas the transcription of glycoprotein mRNA from the S segment antigenome required ∼4 to 6 h. This confirms the temporal separation of viral gene expression expected due to the ambisense coding strategy of arenaviruses and also suggests that antigenomic RNA contained in virions is not transcriptionally active upon entry. Viral replication and transcription peaked at 36 h postinfection, followed by a progressive loss of viral RNAs over the next several days. During persistence, the majority of cells showed repeating cyclical waves of viral transcription and replication followed by the clearance of viral RNA. Thus, our data support a model of LCMV persistence whereby infected cells can spontaneously clear infection and become reinfected by viral reservoir cells that remain in the population. IMPORTANCE Arenaviruses are human pathogens that can establish asymptomatic, lifelong infections in their rodent reservoirs. Several models have been proposed to explain how arenavirus spread is restricted within host rodents, including the periodic accumulation and loss of replication-competent, but transcriptionally incompetent, viral genomes. A limitation of previous studies was the inability to enumerate viral RNA species at the single-cell level. We developed a high-throughput, smFISH assay and used it to quantitate lymphocytic choriomeningitis mammarenavirus (LCMV) replicative and transcriptional RNA species in individual cells at distinct time points following infection. Our findings support a model whereby productively infected cells can clear infection, including viral RNAs and antigen, and later be reinfected. This information improves our understanding of the timing and possible regulation of LCMV genome replication and transcription during infection. Importantly, the smFISH assay and data analysis pipeline developed here is easily adaptable to other RNA viruses. Copyright © 2018 American Society for Microbiology.

Validation and implementation of Planova™ BioEX virus filters in the manufacture of a new liquid intravenous immunoglobulin in China.

PubMed

Ma, Shan; Pang, Guang Li; Shao, Yu Juan; Hongo-Hirasaki, Tomoko; Shang, Meng Xian; Inouye, Marcus; Jian, Chang Yong; Zhu, Meng Zhao; Yang, Hu Hu; Gao, Jian Feng; Xi, Zhi Ying; Song, Dian Wei

2018-03-01

There is a continuous need to improve the viral safety of plasma products, and we here report the development and optimization of a manufacturing-scale virus removal nanofiltration step for intravenous immunoglobulin (IVIG) using the recently introduced Planova™ BioEX filter. IVIG throughput was examined for various operating parameters: transmembrane pressure, temperature, protein concentration, and prefiltration methods. The developed procedure was based on filtering undiluted process solution (50.0 g/l IVIG) under constant transmembrane pressure filtration at 294 kPa and 25 °C following prefiltration with a 0.1 μm MILLEX VV filter. The recovery of IgG was approximately 98%, and no substantial changes in biochemical characteristics were observed before and after nanofiltration in scaled-up production. A viral clearance validation study with parvovirus under worst-case conditions performed at the National Institutes for Food and Drug Control of China (NIFDC) showed PPV logarithmic reduction value (LRV) > 4. Improved viral safety of IVIG can be assured by implementing a Planova BioEX nanofiltration step to ensure effective parvovirus clearance under conditions providing excellent protein recovery and no detectable impact on product biochemical properties. This plasma-derived IVIG product is the first to be certified for parvovirus safety by the NIFDC in China. Copyright © 2018 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

Activity of Oral ALS-008176 in a Respiratory Syncytial Virus Challenge Study.

PubMed

DeVincenzo, John P; McClure, Matthew W; Symons, Julian A; Fathi, Hosnieh; Westland, Christopher; Chanda, Sushmita; Lambkin-Williams, Rob; Smith, Patrick; Zhang, Qingling; Beigelman, Leo; Blatt, Lawrence M; Fry, John

2015-11-19

BACKGROUND Respiratory syncytial virus (RSV) infection is a cause of substantial morbidity and mortality. There is no known effective therapy. METHODS We conducted a randomized, double-blind, clinical trial in healthy adults inoculated with RSV. Participants received the oral nucleoside analogue ALS-008176 or placebo 12 hours after confirmation of RSV infection or 6 days after inoculation. Treatment was administered every 12 hours for 5 days. Viral load, disease severity, resistance, and safety were measured throughout the 28-day study period, with measurement beginning before inoculation. The primary end point was the area under the curve (AUC) for viral load, which was assessed immediately before administration of the first dose through the 12th day after inoculation in participants infected with RSV. RESULTS A total of 62 participants received placebo or one of three ALS-008176 dosing regimens: 1 loading dose of 750 mg followed by 9 maintenance doses of 500 mg (group 1), 1 loading dose of 750 mg followed by 9 maintenance doses of 150 mg (group 2), or 10 doses of 375 mg (group 3). In the 35 infected participants (23 of whom were treated with ALS-008176), the AUCs for viral load for groups 1, 2, and 3 and the placebo group were 59.9, 73.7, 133.4, and 500.9 log10 plaque-forming-unit equivalents × hours per milliliter, respectively (P≤0.001). The time to nondetectability on polymerase-chain-reaction assay (P<0.001), the peak viral load (P≤0.001), the AUC for symptom score (P<0.05), and the AUC for mucus weight were lower in all groups receiving ALS-008176 than in the placebo group. Antiviral activity was greatest in the two groups that received a loading dose--viral clearance was accelerated (P≤0.05), and the AUC for viral load decreased by 85 to 88% as compared with the placebo group. Within this small trial, no viral rebound or resistance was identified. There were no serious adverse events, and there was no need for premature discontinuation of the study drug. CONCLUSIONS In this RSV challenge study, more rapid RSV clearance and a greater reduction of viral load, with accompanying improvements in the severity of clinical disease, were observed in the groups treated with ALS-008176 than in the placebo group. (Funded by Alios BioPharma; ClinicalTrials.gov number, NCT02094365.).

Novel aspects of defensins' involvement in virus-induced autoimmunity in the central nervous system.

PubMed

Kazakos, Evangelos I; Kountouras, Jannis; Polyzos, Stergios A; Deretzi, Georgia

2017-05-01

Recent research on re-circulation of interstitial fluid from the brain parenchyma to the periphery and its inferred importance in immune surveillance dysregulation are changing our conceptualization of the pathophysiology of virus-induced autoimmunity. In this context, it is necessary to reassess the immunomodulatory properties of human defensins that are variably expressed by cerebral microglia, astrocytes and choroid plexus epithelial cells and exhibit complex and often confounding roles in neuroinflammatory processes. Therefore, in this review we describe current contributions in this field and we propose novel hypotheses regarding the potential impact of defensin-related pathways on virus-driven autoimmune neurodegeneration. In this regard, we have previously proposed that abnormal expression of defensins by penetrating the blood-brain barrier (BBB) may contribute to the pathophysiology of Helicobacter pylori-related brain neurodegenerative disorders through variable modulations of innate and adaptive immune responses. We hereby propose that impaired expression of defensins by structural components of the BBB may impede glymphatic circulation and disrupt receptor signalling in pericytes that is essential for microvascular stability, thereby retaining blood-derived toxins and bystander activated T-cells in the brain and further impairing BBB integrity and hampering viral clearance. Autoreactive T-cell infiltrates in neuronaxonal lesions characteristic of chronic central nervous system diseases, such as multiple sclerosis, are directed against both, myelin and non-myelin, antigens the precise nature of which remains enigmatic. Inadequate expression of the autoimmune regulator (AIRE), a gene expressed in medullary thymic epithelial cells, induces the recruitment of defensin-specific T-cells. These cells may access the brain, thereby causing a decrease in defensin expression and subsequent down-regulation of CD91/LRP1-mediated clearance of amyloid-β that ultimately accumulates as protein deposits. It should be highlighted that β-amyloid brain deposits are a hallmark of many neurodegenerative diseases. During human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections, selective elicitation of the VH1-69 antibody subfamily directed against specific, viral glycoprotein epitopes, often correlates with a higher likelihood of developing autoimmune disorders. In addition, we propose that recently described defensin affinity towards the same epitopes may prevent proper viral fusion, but at the expense of augmenting autoimmune reactivity. Moreover, in the context of complex and largely unknown symbiotic relations between host microbiota and pathogenic viruses, we propose that co-stimulation of defensin expression may modulate adaptive immune responses thereby enhancing inflammatory cascades responsible for autoimmunity. Finally, we describe current evidence that supports the hypothesis of a possible involvement of defensins in HCV-related autoimmunity. Exploring further potential implications of human defensins in virus-related autoimmunity may lead to improved strategies for the treatment of neurodegenerative disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

Innate and adaptive immune responses to in utero infection with bovine viral diarrhea virus

USDA-ARS?s Scientific Manuscript database

Infection of pregnant cows with noncytopathic (ncp) BVDV induces rapid innate and adaptive immune responses resulting in clearance of the virus in less than 3 weeks. Seven to 14 days after inoculation of the cow, ncpBVDV crosses the placenta and induces a fetal viremia. Establishment of persistent ...

Progress and Prospects of Anti-HBV Gene Therapy Development

PubMed Central

Maepa, Mohube B.; Roelofse, Ilke; Ely, Abdullah; Arbuthnot, Patrick

2015-01-01

Despite the availability of an effective vaccine against hepatitis B virus (HBV), chronic infection with the virus remains a major global health concern. Current drugs against HBV infection are limited by emergence of resistance and rarely achieve complete viral clearance. This has prompted vigorous research on developing better drugs against chronic HBV infection. Advances in understanding the life cycle of HBV and improvements in gene-disabling technologies have been impressive. This has led to development of better HBV infection models and discovery of new drug candidates. Ideally, a regimen against chronic HBV infection should completely eliminate all viral replicative intermediates, especially covalently closed circular DNA (cccDNA). For the past few decades, nucleic acid-based therapy has emerged as an attractive alternative that may result in complete clearance of HBV in infected patients. Several genetic anti-HBV strategies have been developed. The most studied approaches include the use of antisense oligonucleotides, ribozymes, RNA interference effectors and gene editing tools. This review will summarize recent developments and progress made in the use of gene therapy against HBV. PMID:26263978

Thy1+ Nk Cells from Vaccinia Virus-Primed Mice Confer Protection against Vaccinia Virus Challenge in the Absence of Adaptive Lymphocytes

PubMed Central

Gillard, Geoffrey O.; Bivas-Benita, Maytal; Hovav, Avi-Hai; Grandpre, Lauren E.; Panas, Michael W.; Seaman, Michael S.; Haynes, Barton F.; Letvin, Norman L.

2011-01-01

While immunological memory has long been considered the province of T- and B- lymphocytes, it has recently been reported that innate cell populations are capable of mediating memory responses. We now show that an innate memory immune response is generated in mice following infection with vaccinia virus, a poxvirus for which no cognate germline-encoded receptor has been identified. This immune response results in viral clearance in the absence of classical adaptive T and B lymphocyte populations, and is mediated by a Thy1+ subset of natural killer (NK) cells. We demonstrate that immune protection against infection from a lethal dose of virus can be adoptively transferred with memory hepatic Thy1+ NK cells that were primed with live virus. Our results also indicate that, like classical immunological memory, stronger innate memory responses form in response to priming with live virus than a highly attenuated vector. These results demonstrate that a defined innate memory cell population alone can provide host protection against a lethal systemic infection through viral clearance. PMID:21829360

Limited value of the urinary phenytoin metabolic ratio for the assessment of cytochrome P4502C9 activity in vivo

PubMed Central

TASSANEEYAKUL, WICHITTRA; BIRKETT, DONALD J.; PASS, MICHAEL C.; MINERS, JOHN O.

1996-01-01

Relationships between the ratio of p-hydroxyphenytoin (p-HPPH), the major metabolite of phenytoin, to unchanged phenytoin excreted in urine (the urinary metabolic ratio or MR) were compared with a number of indices of the metabolic clearances of phenytoin and tolbutamide published previously for seventeen subjects separately administered these known cytochrome P4502C9 (CYP2C9) substrates. Significant correlations (rs=0.50–0.60, P<0.05) were observed between the phenytoin MR, derived from either 0–24 or 24–48 h urine collections, and inverse areas under the plasma unbound concentration-time curves (measured over various time intervals) of phenytoin and with plasma unbound tolbutamide clearance. Significant correlations (rs =0.59–0.74) were also observed between the phenytoin MRs and metabolic unbound clearances for p-hydroxyphenytoin formation. Despite the significant correlations, variability in tolbutamide and phenytoin metabolic clearance parameters tended to account for <50% of the variability in phenytoin MR. Correlations between the renal clearance of phenytoin and the phenytoin MRs suggest that variability in the renal clearance of unchanged drug limits the usefulness of the phenytoin MR for the investigation of factors influencing CYP2C9 activity in vivo. PMID:8971435

Renal Function Descriptors in Neonates: Which Creatinine-Based Formula Best Describes Vancomycin Clearance?

PubMed

Bhongsatiern, Jiraganya; Stockmann, Chris; Yu, Tian; Constance, Jonathan E; Moorthy, Ganesh; Spigarelli, Michael G; Desai, Pankaj B; Sherwin, Catherine M T

2016-05-01

Growth and maturational changes have been identified as significant covariates in describing variability in clearance of renally excreted drugs such as vancomycin. Because of immaturity of clearance mechanisms, quantification of renal function in neonates is of importance. Several serum creatinine (SCr)-based renal function descriptors have been developed in adults and children, but none are selectively derived for neonates. This review summarizes development of the neonatal kidney and discusses assessment of the renal function regarding estimation of glomerular filtration rate using renal function descriptors. Furthermore, identification of the renal function descriptors that best describe the variability of vancomycin clearance was performed in a sample study of a septic neonatal cohort. Population pharmacokinetic models were developed applying a combination of age-weight, renal function descriptors, or SCr alone. In addition to age and weight, SCr or renal function descriptors significantly reduced variability of vancomycin clearance. The population pharmacokinetic models with Léger and modified Schwartz formulas were selected as the optimal final models, although the other renal function descriptors and SCr provided reasonably good fit to the data, suggesting further evaluation of the final models using external data sets and cross validation. The present study supports incorporation of renal function descriptors in the estimation of vancomycin clearance in neonates. © 2015, The American College of Clinical Pharmacology.

Duration and clearance of anal human papillomavirus (HPV) infection among women: the Hawaii HPV cohort study.

PubMed

Shvetsov, Yurii B; Hernandez, Brenda Y; McDuffie, Katharine; Wilkens, Lynne R; Zhu, Xuemei; Ning, Lily; Killeen, Jeffrey; Kamemoto, Lori; Goodman, Marc T

2009-03-01

The association of anal cancer with human papillomavirus (HPV) infection is well established; however, little is known about the epidemiology of anal HPV in healthy women. We investigated patterns of duration and clearance of anal HPV infection in a cohort of healthy women in Hawaii. Viral and nonviral determinants of anal HPV clearance were examined in a longitudinal cohort study of 431 sexually active women. At baseline and at 4-month intervals, interviews were conducted and cervical and anal cell specimens were obtained for detection of HPV DNA. Of the 431 women, 50% experienced a total of 414 incident anal HPV infections, reported at 1 clinic visits from baseline through a follow-up period of average duration of 1.2 years. Of these infections, 58% cleared during follow-up. The clearance rate for a high-risk anal infection was 9.2 per 100 woman-months (95% confidence interval [CI], 6.9-11.9 per 100 woman-months), with a median duration of 150 days (95% CI, 132-243 days). The slowest clearing high-risk HPV types were HPV-59 (median clearance time, 350 days) and HPV-58 (median clearance time, 252 days). The median clearance times for HPV-16 and HPV-18, the predominant types associated with anal cancer, were 132 days and 212 days, respectively. Nonviral factors that delayed clearance of anal HPV included douching, long-term tobacco smoking, and anal sex. The majority of anal HPV infections resolve in a relatively short time. Although anal HPV is commonly acquired in healthy women, its rapid clearance suggests limited efficacy of HPV testing as an anal cancer screening tool.

Semen amyloids participate in spermatozoa selection and clearance.

PubMed

Roan, Nadia R; Sandi-Monroy, Nathallie; Kohgadai, Nargis; Usmani, Shariq M; Hamil, Katherine G; Neidleman, Jason; Montano, Mauricio; Ständker, Ludger; Röcker, Annika; Cavrois, Marielle; Rosen, Jared; Marson, Kara; Smith, James F; Pilcher, Christopher D; Gagsteiger, Friedrich; Sakk, Olena; O'Rand, Michael; Lishko, Polina V; Kirchhoff, Frank; Münch, Jan; Greene, Warner C

2017-06-27

Unlike other human biological fluids, semen contains multiple types of amyloid fibrils in the absence of disease. These fibrils enhance HIV infection by promoting viral fusion to cellular targets, but their natural function remained unknown. The similarities shared between HIV fusion to host cell and sperm fusion to oocyte led us to examine whether these fibrils promote fertilization. Surprisingly, the fibrils inhibited fertilization by immobilizing sperm. Interestingly, however, this immobilization facilitated uptake and clearance of sperm by macrophages, which are known to infiltrate the female reproductive tract (FRT) following semen exposure. In the presence of semen fibrils, damaged and apoptotic sperm were more rapidly phagocytosed than healthy ones, suggesting that deposition of semen fibrils in the lower FRT facilitates clearance of poor-quality sperm. Our findings suggest that amyloid fibrils in semen may play a role in reproduction by participating in sperm selection and facilitating the rapid removal of sperm antigens.

Glutamine antagonist-mediated immune suppression decreases pathology but delays virus clearance in mice during nonfatal alphavirus encephalomyelitis.

PubMed

Baxter, Victoria K; Glowinski, Rebecca; Braxton, Alicia M; Potter, Michelle C; Slusher, Barbara S; Griffin, Diane E

2017-08-01

Infection of weanling C57BL/6 mice with the TE strain of Sindbis virus (SINV) causes nonfatal encephalomyelitis associated with hippocampal-based memory impairment that is partially prevented by treatment with 6-diazo-5-oxo-l-norleucine (DON), a glutamine antagonist (Potter et al., J Neurovirol 21:159, 2015). To determine the mechanism(s) of protection, lymph node and central nervous system (CNS) tissues from SINV-infected mice treated daily for 1 week with low (0.3mg/kg) or high (0.6mg/kg) dose DON were examined. DON treatment suppressed lymphocyte proliferation in cervical lymph nodes resulting in reduced CNS immune cell infiltration, inflammation, and cell death compared to untreated SINV-infected mice. Production of SINV-specific antibody and interferon-gamma were also impaired by DON treatment with a delay in virus clearance. Cessation of treatment allowed activation of the antiviral immune response and viral clearance, but revived CNS pathology, demonstrating the ability of the immune response to mediate both CNS damage and virus clearance. Copyright © 2017 Elsevier Inc. All rights reserved.

Circadian Clearance of a Fungal Pathogen from the Lung Is Not Based on Cell-intrinsic Macrophage Rhythms.

PubMed

Chen, Shan; Fuller, Kevin K; Dunlap, Jay C; Loros, Jennifer J

2018-02-01

Circadian rhythms govern immune cell function, giving rise to time-of-day variation in the recognition and clearance of bacterial or viral pathogens; to date, however, no such regulation of the host-fungal interaction has been described. In this report, we use murine models to explore circadian control of either fungal-macrophage interactions in vitro or pathogen clearance from the lung in vivo. First, we show that expression of the important fungal pattern recognition receptor Dectin-1 ( clec7a), from either bone marrow-derived or peritoneum-derived macrophages, is not under circadian regulation at either the level of transcript or cell surface protein expression. Consistent with this finding, the phagocytic activity of macrophages in culture against spores of the pathogen Aspergillus fumigatus also did not vary over time. To account for the multiple cell types and processes that may be coordinated in a circadian fashion in vivo, we examined the clearance of A. fumigatus from the lungs of immunocompetent mice. Interestingly, animals inoculated at night demonstrated a 2-fold enhancement in clearance compared with animals inoculated in the morning. Taken together, our data suggest that while molecular recognition of fungi by immune cells may not be circadian, other processes in vivo may still allow for time-of-day differences in fungal clearance from the lung.

Ultraviolet-C irradiation for inactivation of viruses in foetal bovine serum.

PubMed

Vaidya, Vivek; Dhere, Rajeev; Agnihotri, Snehal; Muley, Ravindra; Patil, Sanjay; Pawar, Amit

2018-07-05

Foetal Bovine Serum (FBS) and porcine trypsin are one of the essential raw materials used in the manufacturing of cell culture based viral vaccines. Being from animal origin, these raw materials can potentially contaminate the final product by known or unknown adventitious agents. The issue is more serious in case of live attenuated viral vaccines, where there is no inactivation step which can take care of such adventitious agents. It is essential to design production processes which can offer maximum viral clearance potential for animal origin products. Ultraviolet-C irradiation is known to inactivate various adventitious viral agents; however there are limited studies on ultraviolet inactivation of viruses in liquid media. We obtained a recently developed UVivatec ultraviolet-C (UV-C) irradiation based viral clearance system for evaluating its efficacy to inactivate selected model viruses. This system has a unique design with spiral path of liquid allowing maximum exposure to UV-C light of a short wavelength of 254 nm. Five live attenuated vaccine viruses and four other model viruses were spiked in tissue culture media and exposed to UV-C irradiation. The pre and post UV-C irradiation samples were analyzed for virus content to find out the extent of inactivation of various viruses. These experiments showed substantial log reduction for the majority of the viruses with few exceptions based on the characteristics of these viruses. Having known the effect of UV irradiation on protein structure, we also evaluated the post irradiation samples of culture media for growth promoting properties using one of the most fastidious human diploid cells (MRC-5). UV-C exposure did not show any notable impact on the nutritional properties of culture media. The use of an UV-C irradiation based system is considered to be promising approach to mitigate the risk of adventitious agents in cell culture media arising through animal derived products. Copyright © 2018 Elsevier Ltd. All rights reserved.

Analysis of Hepatitis C Virus Decline during Treatment with the Protease Inhibitor Danoprevir Using a Multiscale Model

DOE PAGES

Rong, Libin; Guedj, Jeremie; Dahari, Harel; ...

2013-03-14

The current paradigm for studying hepatitis C virus (HCV) dynamics in patients utilizes a standard viral dynamic model that keeps track of uninfected (target) cells, infected cells, and virus. The model does not account for the dynamics of intracellular viral replication, which is the major target of direct-acting antiviral agents (DAAs). In this paper, we describe and study a recently developed multiscale age-structured model that explicitly considers the potential effects of DAAs on intracellular viral RNA production, degradation, and secretion as virus into the circulation. We show that when therapy significantly blocks both intracellular viral RNA production and virus secretion,more » the serum viral load decline has three phases, with slopes reflecting the rate of serum viral clearance, the rate of loss of intracellular viral RNA, and the rate of loss of intracellular replication templates and infected cells, respectively. We also derive analytical approximations of the multiscale model and use one of them to analyze data from patients treated for 14 days with the HCV protease inhibitor danoprevir. Analysis suggests that danoprevir significantly blocks intracellular viral production (with mean effectiveness 99.2%), enhances intracellular viral RNA degradation about 5-fold, and moderately inhibits viral secretion (with mean effectiveness 56%). Finally, the multiscale model can be used to study viral dynamics in patients treated with other DAAs and explore their mechanisms of action in treatment of hepatitis C.« less

Exposure to Electronic Cigarettes Impairs Pulmonary Anti-Bacterial and Anti-Viral Defenses in a Mouse Model

PubMed Central

Sussan, Thomas E.; Gajghate, Sachin; Thimmulappa, Rajesh K.; Ma, Jinfang; Kim, Jung-Hyun; Sudini, Kuladeep; Consolini, Nicola; Cormier, Stephania A.; Lomnicki, Slawo; Hasan, Farhana; Pekosz, Andrew; Biswal, Shyam

2015-01-01

Electronic cigarettes (E-cigs) have experienced sharp increases in popularity over the past five years due to many factors, including aggressive marketing, increased restrictions on conventional cigarettes, and a perception that E-cigs are healthy alternatives to cigarettes. Despite this perception, studies on health effects in humans are extremely limited and in vivo animal models have not been generated. Presently, we determined that E-cig vapor contains 7x1011 free radicals per puff. To determine whether E-cig exposure impacts pulmonary responses in mice, we developed an inhalation chamber for E-cig exposure. Mice that were exposed to E-cig vapor contained serum cotinine concentrations that are comparable to human E-cig users. E-cig exposure for 2 weeks produced a significant increase in oxidative stress and moderate macrophage-mediated inflammation. Since, COPD patients are susceptible to bacterial and viral infections, we tested effects of E-cigs on immune response. Mice that were exposed to E-cig vapor showed significantly impaired pulmonary bacterial clearance, compared to air-exposed mice, following an intranasal infection with Streptococcus pneumonia. This defective bacterial clearance was partially due to reduced phagocytosis by alveolar macrophages from E-cig exposed mice. In response to Influenza A virus infection, E-cig exposed mice displayed increased lung viral titers and enhanced virus-induced illness and mortality. In summary, this study reports a murine model of E-cig exposure and demonstrates that E-cig exposure elicits impaired pulmonary anti-microbial defenses. Hence, E-cig exposure as an alternative to cigarette smoking must be rigorously tested in users for their effects on immune response and susceptibility to bacterial and viral infections. PMID:25651083

Primary Severe Acute Respiratory Syndrome Coronavirus Infection Limits Replication but Not Lung Inflammation upon Homologous Rechallenge

PubMed Central

Clay, Candice; Donart, Nathan; Fomukong, Ndingsa; Knight, Jennifer B.; Lei, Wanli; Price, Lance; Hahn, Fletcher; Van Westrienen, Jesse

2012-01-01

Our knowledge regarding immune-protective and immunopathogenic events in severe acute respiratory syndrome coronavirus (SARS-CoV) infection is limited, and little is known about the dynamics of the immune response at the primary site of disease. Here, an African green monkey (AGM) model was used to elucidate immune mechanisms that facilitate viral clearance but may also contribute to persistent lung inflammation following SARS-CoV infection. During primary infection, SARS-CoV replicated in the AGM lung for up to 10 days. Interestingly, lung inflammation was more prevalent following viral clearance, as leukocyte numbers peaked at 14 days postinfection (dpi) and remained elevated at 28 dpi compared to those of mock-infected controls. Lung macrophages but not dendritic cells were rapidly activated, and both cell types had high activation marker expression at late infection time points. Lung proinflammatory cytokines were induced at 1 to 14 dpi, but most returned to baseline by 28 dpi except interleukin 12 (IL-12) and gamma interferon. In SARS-CoV homologous rechallenge studies, 11 of the 12 animals were free of replicating virus at day 5 after rechallenge. However, incidence and severity of lung inflammation was not reduced despite the limited viral replication upon rechallenge. Evaluating the role of antibodies in immune protection or potentiation revealed a progressive increase in anti-SARS-CoV antibodies in lung and serum that did not correlate temporally or spatially with enhanced viral replication. This study represents one of the first comprehensive analyses of lung immunity, including changes in leukocyte populations, lung-specific cytokines, and antibody responses following SARS-CoV rechallenge in AGMs. PMID:22345460

Alternate Reading Frame Protein (F Protein) of Hepatitis C Virus: Paradoxical Effects of Activation and Apoptosis on Human Dendritic Cells Lead to Stimulation of T Cells

PubMed Central

Samrat, Subodh Kumar; Li, Wen; Singh, Shakti; Kumar, Rakesh; Agrawal, Babita

2014-01-01

Hepatitis C virus (HCV) leads to chronic infection in the majority of infected individuals due to lack, failure, or inefficiency of generated adaptive immune responses. In a minority of patients, acute infection is followed by viral clearance. The immune correlates of viral clearance are not clear yet but have been extensively investigated, suggesting that multispecific and multifunctional cellular immunity is involved. The generation of cellular immunity is highly dependent upon how antigen presenting cells (APCs) process and present various viral antigens. Various structural and non-structural HCV proteins derived from the open reading frame (ORF) have been implicated in modulation of dendritic cells (DCs) and APCs. Besides the major ORF proteins, the HCV core region also encodes an alternate reading frame protein (ARFP or F), whose function in viral pathogenesis is not clear. In the current studies, we sought to determine the role of HCV-derived ARFP in modulating dendritic cells and stimulation of T cell responses. Recombinant adenovirus vectors containing F or core protein derived from HCV (genotype 1a) were prepared and used to endogenously express these proteins in dendritic cells. We made an intriguing observation that endogenous expression of F protein in human DCs leads to contrasting effects on activation and apoptosis of DCs, allowing activated DCs to efficiently internalize apoptotic DCs. These in turn result in efficient ability of DCs to process and present antigen and to prime and stimulate F protein derived peptide-specific T cells from HCV-naive individuals. Taken together, our findings suggest important aspects of F protein in modulating DC function and stimulating T cell responses in humans. PMID:24475147

Adverse Events Post Smallpox-Vaccination: Insights from Tail Scarification Infection in Mice with Vaccinia virus

PubMed Central

Mota, Bruno E. F.; Gallardo-Romero, Nadia; Trindade, Giliane; Keckler, M. Shannon; Karem, Kevin; Carroll, Darin; Campos, Marco A.; Vieira, Leda Q.; da Fonseca, Flávio G.; Ferreira, Paulo C. P.; Bonjardim, Cláudio A.; Damon, Inger K.; Kroon, Erna G.

2011-01-01

Adverse events upon smallpox vaccination with fully-replicative strains of Vaccinia virus (VACV) comprise an array of clinical manifestations that occur primarily in immunocompromised patients leading to significant host morbidity/mortality. The expansion of immune-suppressed populations and the possible release of Variola virus as a bioterrorist act have given rise to concerns over vaccination complications should more widespread vaccination be reinitiated. Our goal was to evaluate the components of the host immune system that are sufficient to prevent morbidity/mortality in a murine model of tail scarification, which mimics immunological and clinical features of smallpox vaccination in humans. Infection of C57BL/6 wild-type mice led to a strictly localized infection, with complete viral clearance by day 28 p.i. On the other hand, infection of T and B-cell deficient mice (Rag1 −/−) produced a severe disease, with uncontrolled viral replication at the inoculation site and dissemination to internal organs. Infection of B-cell deficient animals (µMT) produced no mortality. However, viral clearance in µMT animals was delayed compared to WT animals, with detectable viral titers in tail and internal organs late in infection. Treatment of Rag1 −/− with rabbit hyperimmune anti-vaccinia serum had a subtle effect on the morbidity/mortality of this strain, but it was effective in reduce viral titers in ovaries. Finally, NUDE athymic mice showed a similar outcome of infection as Rag1 −/−, and passive transfer of WT T cells to Rag1 −/− animals proved fully effective in preventing morbidity/mortality. These results strongly suggest that both T and B cells are important in the immune response to primary VACV infection in mice, and that T-cells are required to control the infection at the inoculation site and providing help for B-cells to produce antibodies, which help to prevent viral dissemination. These insights might prove helpful to better identify individuals with higher risk of complications after infection with poxvirus. PMID:21526210

Interleukin-10 Modulation of Virus Clearance and Disease in Mice with Alphaviral Encephalomyelitis.

PubMed

Martin, Nina M; Griffin, Diane E

2018-03-15

Alphaviruses are an important cause of mosquito-borne outbreaks of arthritis, rash, and encephalomyelitis. Previous studies in mice with a virulent strain (neuroadapted SINV [NSV]) of the alphavirus Sindbis virus (SINV) identified a role for Th17 cells and regulation by interleukin-10 (IL-10) in the pathogenesis of fatal encephalomyelitis (K. A. Kulcsar, V. K. Baxter, I. P. Greene, and D. E. Griffin, Proc Natl Acad Sci U S A 111:16053-16058, 2014, https://doi.org/10.1073/pnas.1418966111). To determine the role of virus virulence in generation of immune responses, we analyzed the modulatory effects of IL-10 on disease severity, virus clearance, and the CD4 + T cell response to infection with a recombinant strain of SINV of intermediate virulence (TE12). The absence of IL-10 during TE12 infection led to longer morbidity, more weight loss, higher mortality, and slower viral clearance than in wild-type mice. More severe disease and impaired virus clearance in IL-10 -/- mice were associated with more Th1 cells, fewer Th2 cells, innate lymphoid type 2 cells, regulatory cells, and B cells, and delayed production of antiviral antibody in the central nervous system (CNS) without an effect on Th17 cells. Therefore, IL-10 deficiency led to more severe disease in TE12-infected mice by increasing Th1 cells and by hampering development of the local B cell responses necessary for rapid production of antiviral antibody and virus clearance from the CNS. In addition, the shift from Th17 to Th1 responses with decreased virus virulence indicates that the effects of IL-10 deficiency on immunopathologic responses in the CNS during alphavirus infection are influenced by virus strain. IMPORTANCE Alphaviruses cause mosquito-borne outbreaks of encephalomyelitis, but determinants of outcome are incompletely understood. We analyzed the effects of the anti-inflammatory cytokine IL-10 on disease severity and virus clearance after infection with an alphavirus strain of intermediate virulence. The absence of IL-10 led to longer illness, more weight loss, more death, and slower viral clearance than in mice that produced IL-10. IL-10 influenced development of disease-causing T cells and entry into the brain of B cells producing antiviral antibody. The Th1 pathogenic cell subtype that developed in IL-10-deficient mice infected with a less virulent virus was distinct from the Th17 subtype that developed in response to a more virulent virus, indicating a role for virus strain in determining the immune response. Slow production of antibody in the nervous system led to delayed virus clearance. Therefore, both the virus strain and the host response to infection are important determinants of outcome. Copyright © 2018 American Society for Microbiology.

76 FR 78924 - Agency Forms Undergoing Paperwork Reduction Act Review

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-20

... Budget (OMB) in compliance with the Paperwork Reduction Act (44 U.S.C. chapter 35). To request a copy of these requests, call the CDC Reports Clearance Officer at (404) 639-5960 or send an email to [email protected] National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP), Centers for Disease...

Rapid host immune response and viral dynamics in herpes simplex virus-2 infection

PubMed Central

Schiffer, Joshua T; Corey, Lawrence

2014-01-01

Herpes Simplex Virus-2 (HSV-2) is episodically shed throughout the human genital tract. While high viral load correlates with development of genital ulcers, shedding also commonly occurs even when ulcers are not present, allowing for silent transmission during coitus and contributing to high seroprevalence of HSV-2 worldwide. Frequent viral reactivation occurs despite diverse and complementary host and viral mechanisms within ganglionic tissue that predispose towards latency, suggesting that viral replication may be constantly occurring in a small minority of neurons within the ganglia. Within genital mucosa, the in vivo expansion and clearance rates of HSV-2 are extremely rapid. Resident dendritic cells and memory HSV-specific T cells persist at prior sites of genital tract reactivation, and in conjunction with prompt innate recognition of infected cells, lead to rapid containment of infected cells. Shedding episodes vary greatly in duration and severity within a single person over time: this heterogeneity appears best explained by variation in the densities of host immunity across the genital tract. The fact that immune responses usually control viral replication in genital skin prior to development of lesions provides optimism that enhancing such responses could lead to effective vaccines and immunotherapies. PMID:23467247

Viral lysis, flagellate grazing potential, and bacterial production in Lake Pavin.

PubMed

Bettarel, Y; Amblard, C; Sime-Ngando, T; Carrias, J-F; Sargos, D; Garabétian, F; Lavandier, P

2003-02-01

Abundances of different compartments of the microbial loop (i.e., viruses, heterotrophic bacteria, nonpigmented nanoflagellates, and pigmented nanoflagellates), bacterial heterotrophic production (BHP), viral lysis, and potential flagellate grazing impacts on the bacterial assemblages were estimated during a short-term study (24 h) conducted in June 1998 in the epilimnion (5 m) and metalimnion (10 m) of a moderate-altitude oligomesotrophic lake (Lake Pavin, France). Viral and bacterial abundances were higher in the metalimnion than in the epilimnion, whereas pigmented and nonpigmented nanoflagellates were more numerous in the epilimnion. The control of the BHP due to viral lysis (determined by examination of viral-containing bacteria using a transmission electron microscope) was significantly higher in the meta- (range = 6.0-33.7%, mean = 15.6%) than in the epilimnion (3.5-10.3%, 6.4%). The same was for the losses of BHP from the potential predation by nanoflagellates which ranged from 0.5 to 115.4% (mean = 38.7%) in the epilimnion, and from 0.7 to 97.5% (mean = 66.7%) in the metalimnion. Finally, estimated viral mediated mortality rates from the percentage of visibly infected cells and potential nanoflagellate grazing rates based on assumed clearance rates suggest that flagellates consumed a larger proportion of bacterial production than was lost to viral lysis.

The effects of alcohol on spontaneous clearance of acute hepatitis C virus infection in females versus males.

PubMed

Tsui, Judith I; Mirzazadeh, Ali; Hahn, Judith A; Maher, Lisa; Bruneau, Julie; Grebely, Jason; Hellard, Margaret; Kim, Arthur Y; Shoukry, Naglaa H; Cox, Andrea L; Prins, Maria; Dore, Gregory J; Lauer, Georg; Lloyd, Andrew R; Page, Kimberly

2016-12-01

Approximately one quarter of persons exposed to hepatitis C virus (HCV) will spontaneously clear infection. We undertook this study to investigate the impact of alcohol on likelihood of HCV spontaneous viral clearance stratified by sex groups. Pooled data from an international collaboration of prospective observational studies of incident HIV and HCV infection in high-risk cohorts (the InC3 Study) was restricted to 411 persons (or 560.7 person-years of observation) with documented acute HCV infection and data regarding alcohol use. The predictor of interest was self-reported alcohol use at or after estimated date of incident HCV infection and the outcome was HCV spontaneous clearance. Sex stratified Cox proportional hazards models were used to evaluate the association between alcohol and spontaneous clearance, adjusting for age, race/ethnicity, and IFNL4 genotype. The median age was 28.5 years, 30.4% were women, 87.2% were white, and 71.8% reported alcohol use at or after incident infection. There were 89 (21.6%) cases of spontaneous clearance observed, 39 (31.2%) among women and 50 (17.5%) in men (p<0.01). Overall, spontaneous clearance occurred less frequently among participants who drank alcohol compared to those who did not drink (18.9% v. 28.5%, p=0.03). After adjustment for other covariates, alcohol was significantly and independently associated with lower relative hazards for spontaneous clearance of HCV in women (AHR=0.35; 95% CI: 0.19-0.66; p=0.001) but not in men (AHR=0.63; 95% CI: 0.36-1.09; p=0.10). Results indicate that abstaining from drinking alcohol may increase the likelihood of spontaneous clearance among women. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The Effects of Alcohol on Spontaneous Clearance of Acute Hepatitis C Virus Infection in Females versus Males

PubMed Central

Tsui, Judith I.; Mirzazadeh, Ali; Hahn, Judith A.; Maher, Lisa; Bruneau, Julie; Grebely, Jason; Hellard, Margaret; Kim, Arthur Y.; Shoukry, Naglaa H.; Cox, Andrea L.; Prins, Maria; Dore, Gregory; Lauer, Georg; Lloyd, Andrew; Page, Kimberly

2016-01-01

Background Approximately one quarter of persons exposed to hepatitis C virus (HCV) will spontaneously clear infection. We undertook this study to investigate the impact of alcohol on likelihood of HCV spontaneous viral clearance stratified by sex groups. Methods Pooled data from an international collaboration of prospective observational studies of incident HIV and HCV infection in high-risk cohorts (the InC3 Study) was restricted to 411 persons (or 560.7 person-years of observation) with documented acute HCV infection and data regarding alcohol use. The predictor of interest was self-reported alcohol use at or after estimated date of incident HCV infection and the outcome was HCV spontaneous clearance. Sex stratified Cox proportional hazards models were used to evaluate the association between alcohol and spontaneous clearance, adjusting for age, race/ethnicity, and IFNL4 genotype. Results The median age was 28.5 years, 30.4% were women, 87.2% were white, and 71.8% reported alcohol use at or after incident infection. There were 89 (21.6%) cases of spontaneous clearance observed, 39 (31.2%) among women and 50 (17.5%) in men (p<0.01). Overall, spontaneous clearance occurred less frequently among participants who drank alcohol compared to those who did not drink (18.9% v. 28.5%, p=0.03). After adjustment for other covariates, alcohol was significantly and independently associated with lower relative hazards for spontaneous clearance of HCV in women (AHR=0.35; 95% CI: 0.19-0.66; p=0.001) but not in men (AHR=0.63; 95% CI: 0.36-1.09; p=0.10). Conclusion Results indicate that abstaining from drinking alcohol may increase the likelihood of spontaneous clearance among women. PMID:27816863

Legionnaire's Disease and Influenza.

PubMed

Magira, Eleni E; Zakynthinos, Sryros

2017-03-01

Legionella pneumophila and influenza types A and B viruses can cause either community-acquired pneumonia with respiratory failure, or Legionella infection could attribute to influenza infection with potentially fatal prognosis. Copathogenesis between pandemic influenza and bacteria is characterized by complex interactions between coinfecting pathogens and the host. Understanding the underlying reason of the emersion of the secondary bacterial infection during an influenza infection is challenging. The dual infection has an impact on viral control and may delay viral clearance. Effective vaccines and antiviral therapy are crucial to increase resistance toward influenza, decrease the prevalence of influenza, and possibly interrupt the potential secondary bacterial infections. Copyright © 2016 Elsevier Inc. All rights reserved.

Loss model for off-design performance analysis of radial turbines with pivoting-vane, variable-area stators

NASA Technical Reports Server (NTRS)

Meitner, P. L.; Glassman, A. J.

1980-01-01

An off-design performance loss model is developed for variable-area (pivoted vane) radial turbines. The variation in stator loss with stator area is determined by a viscous loss model while the variation in rotor loss due to stator area variation (for no stator end-clearance gap) is determined through analytical matching of experimental data. An incidence loss model is also based on matching of the experimental data. A stator vane end-clearance leakage model is developed and sample calculations are made to show the predicted effects of stator vane end-clearance leakage on performance.

Population pharmacokinetic and pharmacogenetic analysis of tacrolimus in paediatric liver transplant patients

PubMed Central

Abdel Jalil, Mariam H; Hawwa, Ahmed F; McKiernan, Patrick J; Shields, Michael D; McElnay, James C

2014-01-01

Aims To build a population pharmacokinetic model that describes the apparent clearance of tacrolimus and the potential demographic, clinical and genetically controlled factors that could lead to inter-patient pharmacokinetic variability within children following liver transplantation. Methods The present study retrospectively examined tacrolimus whole blood pre-dose concentrations (n = 628) of 43 children during their first year post-liver transplantation. Population pharmacokinetic analysis was performed using the non-linear mixed effects modelling program (nonmem) to determine the population mean parameter estimate of clearance and influential covariates. Results The final model identified time post-transplantation and CYP3A5*1 allele as influential covariates on tacrolimus apparent clearance according to the following equation: where TVCL is the typical value for apparent clearance, TPT is time post-transplantation in days and the CYP3A5 is 1 where *1 allele is present and 0 otherwise. The population estimate and inter-individual variability (%CV) of tacrolimus apparent clearance were found to be 0.977 l h−1 kg−1 (95% CI 0.958, 0.996) and 40.0%, respectively, while the residual variability between the observed and predicted concentrations was 35.4%. Conclusion Tacrolimus apparent clearance was influenced by time post-transplantation and CYP3A5 genotypes. The results of this study, once confirmed by a large scale prospective study, can be used in conjunction with therapeutic drug monitoring to recommend tacrolimus dose adjustments that take into account not only body weight but also genetic and time-related changes in tacrolimus clearance. PMID:23738951

A model of clearance rate regulation in mussels

NASA Astrophysics Data System (ADS)

Fréchette, Marcel

2012-10-01

Clearance rate regulation has been modelled as an instantaneous response to food availability, independent of the internal state of the animals. This view is incompatible with latent effects during ontogeny and phenotypic flexibility in clearance rate. Internal-state regulation of clearance rate is required to account for these patterns. Here I develop a model of internal-state based regulation of clearance rate. External factors such as suspended sediments are included in the model. To assess the relative merits of instantaneous regulation and internal-state regulation, I modelled blue mussel clearance rate and growth using a DEB model. In the usual standard feeding module, feeding is governed by a Holling's Type II response to food concentration. In the internal-state feeding module, gill ciliary activity and thus clearance rate are driven by internal reserve level. Factors such as suspended sediments were not included in the simulations. The two feeding modules were compared on the basis of their ability to capture the impact of latent effects, of environmental heterogeneity in food abundance and of physiological flexibility on clearance rate and individual growth. The Holling feeding module was unable to capture the effect of any of these sources of variability. In contrast, the internal-state feeding module did so without any modification or ad hoc calibration. Latent effects, however, appeared transient. With simple annual variability in temperature and food concentration, the relationship between clearance rate and food availability predicted by the internal-state feeding module was quite similar to that observed in Norwegian fjords. I conclude that in contrast with the usual Holling feeding module, internal-state regulation of clearance rate is consistent with well-documented growth and clearance rate patterns.

Sequential Bottlenecks Drive Viral Evolution in Early Acute Hepatitis C Virus Infection

PubMed Central

McElroy, Kerensa; Gaudieri, Silvana; Pham, Son T.; Chopra, Abha; Cameron, Barbara; Maher, Lisa; Dore, Gregory J.; White, Peter A.; Lloyd, Andrew R.

2011-01-01

Hepatitis C is a pandemic human RNA virus, which commonly causes chronic infection and liver disease. The characterization of viral populations that successfully initiate infection, and also those that drive progression to chronicity is instrumental for understanding pathogenesis and vaccine design. A comprehensive and longitudinal analysis of the viral population was conducted in four subjects followed from very early acute infection to resolution of disease outcome. By means of next generation sequencing (NGS) and standard cloning/Sanger sequencing, genetic diversity and viral variants were quantified over the course of the infection at frequencies as low as 0.1%. Phylogenetic analysis of reassembled viral variants revealed acute infection was dominated by two sequential bottleneck events, irrespective of subsequent chronicity or clearance. The first bottleneck was associated with transmission, with one to two viral variants successfully establishing infection. The second occurred approximately 100 days post-infection, and was characterized by a decline in viral diversity. In the two subjects who developed chronic infection, this second bottleneck was followed by the emergence of a new viral population, which evolved from the founder variants via a selective sweep with fixation in a small number of mutated sites. The diversity at sites with non-synonymous mutation was higher in predicted cytotoxic T cell epitopes, suggesting immune-driven evolution. These results provide the first detailed analysis of early within-host evolution of HCV, indicating strong selective forces limit viral evolution in the acute phase of infection. PMID:21912520

pelo Is Required for High Efficiency Viral Replication

PubMed Central

Wu, Xiurong; He, Wan-Ting; Tian, Shuye; Meng, Dan; Li, Yuanyue; Chen, Wanze; Li, Lisheng; Tian, Lili; Zhong, Chuan-Qi; Han, Felicia; Chen, Jianming; Han, Jiahuai

2014-01-01

Viruses hijack host factors for their high speed protein synthesis, but information about these factors is largely unknown. In searching for genes that are involved in viral replication, we carried out a forward genetic screen for Drosophila mutants that are more resistant or sensitive to Drosophila C virus (DCV) infection-caused death, and found a virus-resistant line in which the expression of pelo gene was deficient. Our mechanistic studies excluded the viral resistance of pelo deficient flies resulting from the known Drosophila anti-viral pathways, and revealed that pelo deficiency limits the high level synthesis of the DCV capsid proteins but has no or very little effect on the expression of some other viral proteins, bulk cellular proteins, and transfected exogenous genes. The restriction of replication of other types of viruses in pelo deficient flies was also observed, suggesting pelo is required for high level production of capsids of all kinds of viruses. We show that both pelo deficiency and high level DCV protein synthesis increase aberrant 80S ribosomes, and propose that the preferential requirement of pelo for high level synthesis of viral capsids is at least partly due to the role of pelo in dissociation of stalled 80S ribosomes and clearance of aberrant viral RNA and proteins. Our data demonstrated that pelo is a host factor that is required for high efficiency translation of viral capsids and targeting pelo could be a strategy for general inhibition of viral infection. PMID:24722736

Semen amyloids participate in spermatozoa selection and clearance

PubMed Central

Roan, Nadia R; Sandi-Monroy, Nathallie; Kohgadai, Nargis; Usmani, Shariq M; Hamil, Katherine G; Neidleman, Jason; Montano, Mauricio; Ständker, Ludger; Röcker, Annika; Cavrois, Marielle; Rosen, Jared; Marson, Kara; Smith, James F; Pilcher, Christopher D; Gagsteiger, Friedrich; Sakk, Olena; O’Rand, Michael; Lishko, Polina V; Kirchhoff, Frank

2017-01-01

Unlike other human biological fluids, semen contains multiple types of amyloid fibrils in the absence of disease. These fibrils enhance HIV infection by promoting viral fusion to cellular targets, but their natural function remained unknown. The similarities shared between HIV fusion to host cell and sperm fusion to oocyte led us to examine whether these fibrils promote fertilization. Surprisingly, the fibrils inhibited fertilization by immobilizing sperm. Interestingly, however, this immobilization facilitated uptake and clearance of sperm by macrophages, which are known to infiltrate the female reproductive tract (FRT) following semen exposure. In the presence of semen fibrils, damaged and apoptotic sperm were more rapidly phagocytosed than healthy ones, suggesting that deposition of semen fibrils in the lower FRT facilitates clearance of poor-quality sperm. Our findings suggest that amyloid fibrils in semen may play a role in reproduction by participating in sperm selection and facilitating the rapid removal of sperm antigens. DOI: http://dx.doi.org/10.7554/eLife.24888.001 PMID:28653619

Linear variability of gait according to socioeconomic status in elderly

PubMed Central

2016-01-01

Aim: To evaluate the linear variability of comfortable gait according to socioeconomic status in community-dwelling elderly. Method: For this cross-sectional observational study 63 self- functioning elderly were categorized according to the socioeconomic level on medium-low (n= 33, age 69.0 ± 5.0 years) and medium-high (n= 30, age 71.0 ± 6.0 years). Each participant was asked to perform comfortable gait speed for 3 min on an 40 meters elliptical circuit, recording in video five strides which were transformed into frames, determining the minimum foot clearance, maximum foot clearance and stride length. The intra-group linear variability was calculated by the coefficient of variation in percent. Results: The trajectory parameters variability is not different according to socioeconomic status with a 30% (range= 15-55%) for the minimum foot clearance and 6% (range= 3-8%) in maximum foot clearance. Meanwhile, the stride length consistently was more variable in the medium-low socioeconomic status for the overall sample (p= 0.004), female (p= 0.041) and male gender (p= 0.007), with values near 4% ​​(range = 2.5-5.0%) in the medium-low and 2% (range = 1.5-3.5%) in the medium-high. Conclusions: The intra-group linear variability is consistently higher and within reference parameters for stride length during comfortable gait for elderly belonging to medium-low socioeconomic status. This might be indicative of greater complexity and consequent motor adaptability. PMID:27546931

Induction of innate immunity and its perturbation by influenza viruses.

PubMed

Goraya, Mohsan Ullah; Wang, Song; Munir, Muhammad; Chen, Ji-Long

2015-10-01

Influenza A viruses (IAV) are highly contagious pathogens causing dreadful losses to human and animal, around the globe. IAVs first interact with the host through epithelial cells, and the viral RNA containing a 5'-triphosphate group is thought to be the critical trigger for activation of effective innate immunity via pattern recognition receptors-dependent signaling pathways. These induced immune responses establish the antiviral state of the host for effective suppression of viral replication and enhancing viral clearance. However, IAVs have evolved a variety of mechanisms by which they can invade host cells, circumvent the host immune responses, and use the machineries of host cells to synthesize and transport their own components, which help them to establish a successful infection and replication. In this review, we will highlight the molecular mechanisms of how IAV infection stimulates the host innate immune system and strategies by which IAV evades host responses.

Control of HIV infection by IFN-α: implications for latency and a cure.

PubMed

Bourke, Nollaig M; Napoletano, Silvia; Bannan, Ciaran; Ahmed, Suaad; Bergin, Colm; McKnight, Áine; Stevenson, Nigel J

2018-03-01

Viral infections, including HIV, trigger the production of type I interferons (IFNs), which in turn, activate a signalling cascade that ultimately culminates with the expression of anti-viral proteins. Mounting evidence suggests that type I IFNs, in particular IFN-α, play a pivotal role in limiting acute HIV infection. Highly active anti-retroviral treatment reduces viral load and increases life expectancy in HIV positive patients; however, it fails to fully eliminate latent HIV reservoirs. To revisit HIV as a curable disease, this article reviews a body of literature that highlights type I IFNs as mediators in the control of HIV infection, with particular focus on the anti-HIV restriction factors induced and/or activated by IFN-α. In addition, we discuss the relevance of type I IFN treatment in the context of HIV latency reversal, novel therapeutic intervention strategies and the potential for full HIV clearance.

The Ad5 [E1-, E2b-]-based vector: a new and versatile gene delivery platform

NASA Astrophysics Data System (ADS)

Jones, Frank R.; Gabitzsch, Elizabeth S.; Balint, Joseph P.

2015-05-01

Based upon advances in gene sequencing and construction, it is now possible to identify specific genes or sequences thereof for gene delivery applications. Recombinant adenovirus serotype-5 (Ad5) viral vectors have been utilized in the settings of gene therapy, vaccination, and immunotherapy but have encountered clinical challenges because they are recognized as foreign entities to the host. This recognition leads to an immunologic clearance of the vector that contains the inserted gene of interest and prevents effective immunization(s). We have reported on a new Ad5-based viral vector technology that can be utilized as an immunization modality to induce immune responses even in the presence of Ad5 vector immunity. We have reported successful immunization and immunotherapy results to infectious diseases and cancers. This improved recombinant viral platform (Ad5 [E1-, E2b-]) can now be utilized in the development of multiple vaccines and immunotherapies.

Role of CXCR3 in the Immune Response to Murine Gammaherpesvirus 68

PubMed Central

Lee, Bong Joo; Giannoni, Francesca; Lyon, Ashley; Yada, Shinichiro; Lu, Bao; Gerard, Craig; Sarawar, Sally R.

2005-01-01

The chemokine IP-10 (CXCL10) and its cellular receptor CXCR3 are upregulated in the lung during murine gammaherpesvirus 68 (MHV-68) infection. In order to determine the role of the CXCR3 chemokine receptor in the immune response to MHV-68, CXCR3−/− mice were infected with the virus. CXCR3−/− mice showed delayed clearance of replicating MHV-68 from the lungs. This correlated with delayed T-cell recruitment to the lungs and reduced cytolytic activity prior to viral clearance. Splenomegaly and the numbers of latently infected cells per spleen were transiently increased. Ηowever, CXCR3−/− mice showed normal virus-specific antibody titers and effective long-term control of MHV-68 infection. PMID:15994833

Risk mitigation strategies for viral contamination of biotechnology products: consideration of best practices.

PubMed

Rosenberg, Amy S; Cherney, Barry; Brorson, Kurt; Clouse, Kathleen; Kozlowski, Steven; Hughes, Patricia; Friedman, Rick

2011-01-01

CONFERENCE PROCEEDING Proceedings of the PDA/FDA Adventitious Viruses in Biologics: Detection and Mitigation Strategies Workshop in Bethesda, MD, USA; December 1-3, 2010 Guest Editors: Arifa Khan (Bethesda, MD), Patricia Hughes (Bethesda, MD) and Michael Wiebe (San Francisco, CA) Viral contamination of biotech product facilities is a potentially devastating manufacturing risk and, unfortunately, is more common than is generally reported or previously appreciated. Although viral contaminants of biotech products are thought to originate principally from biological raw materials, all potential process risks merit evaluation. Limitations to existing methods for virus detection are becoming evident as emerging viruses have contaminated facilities and disrupted supplies of critical products. New technologies, such as broad-based polymerase chain reaction screens for multiple virus types, are increasingly becoming available to detect adventitious viral contamination and thus, mitigate risks to biotech products and processes. Further, the industry embrace of quality risk management that promotes improvements in testing stratagems, enhanced viral inactivation methods for raw materials, implementation and standardization of robust viral clearance procedures, and efforts to learn from both epidemiologic screening of raw material sources and from the experience of other manufacturers with regard to this problem will serve to enhance the safety of biotech products available to patients. Based on this evolving landscape, we propose a set of principles for manufacturers of biotech products: Pillars of Risk Mitigation for Viral Contamination of Biotech Products.

Hepatitis B and C coinfection in a real-life setting: viral interactions and treatment issues.

PubMed

Papadopoulos, Nikolaos; Papavdi, Maria; Pavlidou, Anna; Konstantinou, Dimitris; Kranidioti, Hariklia; Kontos, George; Koskinas, John; Papatheodoridis, George V; Manolakopoulos, Spilios; Deutsch, Melanie

2018-01-01

Only limited data concerning hepatitis B (HBV) and C viruses (HCV) coinfection are available. Direct-acting antivirals (DAAs) may be more effective for HCV clearance than interferon (IFN)-based regimens with a risk of HBV reactivation. We retrospectively enrolled 40 HBV/HCV-coinfected patients to evaluate their clinical profile and treatment outcomes. Chronic dual infection was present in 25/40 (62.5%) patients, acute HCV superinfection in 5/40 (12.5%) patients and acute HBV superinfection in 10/40 (25%). Twenty-five patients (62.5%) were treated: 16/25 (64%) with IFN, 4/25 (16%) with nucleot(s)ide analogs (NUCs) and 5/25 (20%) with DAAs. Of the 16 patients treated with IFN-based therapy, 6 (37.5%) achieved both sustained virological response (SVR) and HBsAg clearance. Of the 4 patients treated with NUCs, one (25%) achieved both SVR and HBsAg clearance. All five patients treated with DAAs (100%) achieved SVR, while one case of HBV reactivation was recorded. Fifteen of the 40 patients (37.5%) did not receive any treatment. Eight of them (53.5%) presented with acute HBV superinfection: spontaneous HCV clearance was recorded in 5/8 (62.5%), while HBsAg clearance occurred in 6/8 (75%). Three of them (20%) presented with acute HCV superinfection; spontaneous HCV clearance was recorded in one of the three (33.5%). The other four patients (26.5%) presented with dual HBV/HCV infection. A significant proportion of patients presented with active HBV replication. Treatment with DAAs seems to be efficacious for HCV eradication. However, clinicians should be aware of HBV reactivation. HBV superinfection may lead to both HBsAg and HCV clearance.

Antibody responses and viral load in patients with Crimean-Congo hemorrhagic fever: a comprehensive analysis during the early stages of the infection.

PubMed

Ergunay, Koray; Kocak Tufan, Zeliha; Bulut, Cemal; Kinikli, Sami; Demiroz, Ali Pekcan; Ozkul, Aykut

2014-05-01

This study was performed to assess viral load, viral nucleocapsid (N), and glycoprotein precursor (GPC) antibodies in consecutive samples obtained from Crimean-Congo hemorrhagic fever patients to reveal viral replication kinetics and antiviral immune responses during the early stages of the infection. Among 116 samples from 20 individuals, 43.9% and 76.7% were positive for viral RNA and IgM/IgG antibodies, respectively, whereas both markers could be detected in 22.4%. Mean duration of viremia was 3 days (range: 1-6 days). N-IgM antibodies were identified as the initial serological marker during the infection, becoming detectable in a median of 2-3 days after disease onset, followed by GPC-IgM (4-6 days) and IgG antibodies (5-6 days). Clearance of viremia followed or coincided N-IgM response. Partial S gene sequences amplified in viremic patients were identical or closely related to previously characterized strains and grouped within European lineage I group II viruses via neighbor-joining analysis without significant amino acid substitutions. Copyright © 2014 Elsevier Inc. All rights reserved.

Moral Waivers and Suitability for High Security Military Jobs

DTIC Science & Technology

1988-12-01

Score 9 High School Diploma 10 Service Entry Variables 11 Months in the Delayed Entry Program (DEP) 11 DoD Primary Occupation Code ( DPOC ) 14...services 6 4. DoD Primary Occupational ( DPOC ) Areas 14 5. Cumulative percentage of personnel who received Bis during first six months of...Entry Variables - Months in the Delayed Entry Program (DEP) - DoD Primary Occupation Code ( DPOC ) Clearance Criteria - Issue case - Clearance status

Rapid reversal of innate immune dysregulation in blood of patients and livers of humanized mice with HCV following DAA therapy

PubMed Central

Burchill, Matthew A.; Roby, Justin A.; Crochet, Nanette; Wind-Rotolo, Megan; Stone, Amy E.; Edwards, Michael G.; Dran, Rachael J.; Kriss, Michael S.; Gale, Michael

2017-01-01

Chronic hepatitis C virus (HCV) infection results in sustained immune activation in both the periphery and hepatic tissue. HCV infection induces innate immune signaling that is responsible for recognition of dsRNA, leading to activation of transcription factors and production of Type I and III IFNs, as well as pro-inflammatory cytokines and chemokines. Continued activation of host-immune mediated inflammation is thought to contribute to pathologic changes that result in progressive hepatic fibrosis. The current standard treatment for chronic HCV infection is directly-acting antivirals (DAAs), which have provided the unique opportunity to determine whether successful, rapid treatment-induced eradication of viral RNA normalizes the dysregulated antiviral innate immune response in patients chronically infected with HCV. Results First, in patients receiving two different combinations of DAAs, we found that DAAs induced not only rapid viral clearance, but also a re-setting of antiviral immune responses in the peripheral blood. Specifically, we see a rapid decline in the expression of genes associated with chronic IFN stimulation (IFIT3, USP18, IFIT1) as well as a rapid decline in genes associated with inflammation (IL1β, CXCL10, CXCL11) in the peripheral blood that precedes the complete removal of virus from the blood. Interestingly, this rapid reversal of innate immune activation was not seen in patients who successfully clear chronic HCV infection using IFN-based therapy. Next, using a novel humanized mouse model (Fah-/-RAG2-/-IL2rgnull—FRG), we assessed the changes that occur in the hepatic tissue following DAA treatment. DAA-mediated rapid HCV clearance resulted in blunting of the expression of proinflammatory responses while functionally restoring the RIG-I/MAVS axis in the liver of humanized mice. Conclusions Collectively, our data demonstrate that the rapid viral clearance following treatment with DAAs results in the rebalancing of innate antiviral response in both the peripheral blood and the liver as well as enhanced antiviral signaling within previously infected hepatocytes. PMID:29040318

Loss model for off-design performance analysis of radial turbines with pivoting-vane, variable-area stators

NASA Technical Reports Server (NTRS)

Meitner, P. L.; Glassman, A. J.

1980-01-01

An off-design performance loss model for a radial turbine with pivoting, variable-area stators is developed through a combination of analytical modeling and experimental data analysis. A viscous loss model is used for the variation in stator loss with setting angle, and stator vane end-clearance leakage effects are predicted by a clearance flow model. The variation of rotor loss coefficient with stator setting angle is obtained by means of an analytical matching of experimental data for a rotor that was tested with six stators, having throat areas from 20 to 144% of the design area. An incidence loss model is selected to obtain best agreement with experimental data. The stator vane end-clearance leakage model predicts increasing mass flow and decreasing efficiency as a result of end-clearances, with changes becoming significantly larger with decreasing stator area.

The Effect of a Six-Month Dancing Program on Motor-Cognitive Dual-Task Performance in Older Adults.

PubMed

Hamacher, Dennis; Hamacher, Daniel; Rehfeld, Kathrin; Hökelmann, Anita; Schega, Lutz

2015-10-01

Dancing is a complex sensorimotor activity involving physical and mental elements which have positive effects on cognitive functions and motor control. The present randomized controlled trial aims to analyze the effects of a dancing program on the performance on a motor-cognitive dual task. Data of 35 older adults, who were assigned to a dancing group or a health-related exercise group, are presented in the study. In pretest and posttest, we assessed cognitive performance and variability of minimum foot clearance, stride time, and stride length while walking. Regarding the cognitive performance and the stride-to-stride variability of minimum foot clearance, interaction effects have been found, indicating that dancing lowers gait variability to a higher extent than conventional health-related exercise. The data show that dancing improves minimum foot clearance variability and cognitive performance in a dual-task situation. Multi-task exercises (like dancing) might be a powerful tool to improve motor-cognitive dual-task performance.

Retrospective Evaluation of Milrinone Pharmacokinetics in Children With Kidney Injury.

PubMed

Gist, Katja M; Mizuno, Tomoyuki; Goldstein, Stuart L; Vinks, Alexander

2015-12-01

Milrinone is an inotropic agent with vasodilating properties used in the treatment of ventricular dysfunction. Milrinone is predominantly eliminated by the kidneys and accumulates in the setting of acute kidney injury (AKI). The purpose of this study was to evaluate milrinone pharmacokinetics in children with AKI with or without continuous renal replacement therapy (CRRT). Retrospective collection of milrinone therapeutic drug monitoring data in patients with AKI, including those requiring CRRT, through chart review from January 2008 to March 2014. Pharmacokinetic (PK) data were analyzed by Bayesian estimation using a pediatric population PK model (MW/Pharm). Clearance estimates were allometrically scaled to body weight. Data on 11 patients were available for analysis. Three patients required CRRT. Milrinone concentrations during continuous infusion varied 30-fold and ranged from 44 to 1343 ng/mL. Of the 33 samples obtained in 11 patients, 24 were outside the target range (72.7%), with 16 (48.5%) above and 8 (24.2%) below. Patients with AKI had significantly lower milrinone clearance (4.72 ± 2.26 L/h per 70 kg) compared with published data in patients without AKI. There was large between-patient variability in milrinone clearance (range: 2.91-13.6 L/h per 70 kg). Clearance in patients on CRRT ranged from 2.8 to 7.19 L/h per 70 kg. A significant correlation between milrinone clearance and estimated creatinine clearance was observed (r = 0.70, P = 0.0097). Allometrically scaled milrinone clearance was lower in the youngest patients (younger than 2 years), suggestive of ongoing renal maturation and existing AKI. Pediatric patients with AKI have significantly lower milrinone clearance compared with published data in patients without AKI. Large variability was noted in milrinone concentrations, and they were frequently outside the target range. The large between-patient variability in milrinone concentrations suggests that dosing regimens should be individualized in this population of critically ill patients. Evaluation of PK model-based milrinone dose optimization and the use of biomarkers as predictors of changes in clearance warrant further study.

Progress in Quantitative Viral Load Testing: Variability and Impact of the WHO Quantitative International Standards

PubMed Central

Sun, Y.; Tang, L.; Procop, G. W.; Hillyard, D. R.; Young, S. A.; Caliendo, A. M.

2016-01-01

ABSTRACT It has been hoped that the recent availability of WHO quantitative standards would improve interlaboratory agreement for viral load testing; however, insufficient data are available to evaluate whether this has been the case. Results from 554 laboratories participating in proficiency testing surveys for quantitative PCR assays of cytomegalovirus (CMV), Epstein-Barr virus (EBV), BK virus (BKV), adenovirus (ADV), and human herpesvirus 6 (HHV6) were evaluated to determine overall result variability and then were stratified by assay manufacturer. The impact of calibration to international units/ml (CMV and EBV) on variability was also determined. Viral loads showed a high degree of interlaboratory variability for all tested viruses, with interquartile ranges as high as 1.46 log10 copies/ml and the overall range for a given sample up to 5.66 log10 copies/ml. Some improvement in result variability was seen when international units were adopted. This was particularly the case for EBV viral load results. Variability in viral load results remains a challenge across all viruses tested here; introduction of international quantitative standards may help reduce variability and does so more or less markedly for certain viruses. PMID:27852673

Treatment response of airway clearance assessed by single-breath washout in children with cystic fibrosis.

PubMed

Abbas, Chiara; Singer, Florian; Yammine, Sophie; Casaulta, Carmen; Latzin, Philipp

2013-12-01

We studied the ability of 4 single-breath gas washout (SBW) tests to measure immediate effects of airway clearance in children with CF. 25 children aged 4-16 years with CF performed pulmonary function tests to assess short-term variability at baseline and response to routine airway clearance. Tidal helium and sulfur hexafluoride (double-tracer gas: DTG) SBW, tidal capnography, tidal and vital capacity nitrogen (N2) SBW and spirometry were applied. We analyzed the gasses' phase III slope (SnIII--normalized for tidal volume) and FEV1 from spirometry. SnIII from tidal DTG-SBW, SnIII from vital capacity N2-SBW, and FEV1 improved significantly after airway clearance. From these tests, individual change of SnIII from tidal DTG-SBW and FEV1 exceeded short-term variability in 10 and 6 children. With the tidal DTG-SBW, an easy and promising test for peripheral gas mixing efficiency, immediate pulmonary function response to airway clearance can be assessed in CF children. Copyright © 2013 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Slc15a4, a gene required for pDC sensing of TLR ligands, is required to control persistent viral infection.

PubMed

Blasius, Amanda L; Krebs, Philippe; Sullivan, Brian M; Oldstone, Michael B; Popkin, Daniel L

2012-09-01

Plasmacytoid dendritic cells (pDCs) are the major producers of type I IFN in response to viral infection and have been shown to direct both innate and adaptive immune responses in vitro. However, in vivo evidence for their role in viral infection is lacking. We evaluated the contribution of pDCs to acute and chronic virus infection using the feeble mouse model of pDC functional deficiency. We have previously demonstrated that feeble mice have a defect in TLR ligand sensing. Although pDCs were found to influence early cytokine secretion, they were not required for control of viremia in the acute phase of the infection. However, T cell priming was deficient in the absence of functional pDCs and the virus-specific immune response was hampered. Ultimately, infection persisted in feeble mice. We conclude that pDCs are likely required for efficient T cell priming and subsequent viral clearance. Our data suggest that reduced pDC functionality may lead to chronic infection.

Antiviral T Cells for Adenovirus in the Pretransplant Period: A Bridge Therapy for Severe Combined Immunodeficiency.

PubMed

Miller, Holly K; Hanley, Patrick J; Lang, Haili; Lazarski, Christopher A; Chorvinsky, Elizabeth A; McCormack, Sarah; Roesch, Lauren; Albihani, Shuroug; Dean, Marcus; Hoq, Fahmida; Adams, Roberta H; Bollard, Catherine M; Keller, Michael D

2018-05-09

Viral infections can be life threatening in patients with severe combined immunodeficiency (SCID) and other forms of profound primary immunodeficiency disorders both before and after hematopoietic stem cell transplantation (HSCT). Adoptive immunotherapy with virus-specific T cells (VSTs) has been utilized in many patients in the setting of HSCT, but has very rarely been attempted for treatment of viral infections before HSCT. Here we describe the use of VSTs in an infant with RAG1 SCID who had developed disseminated adenovirus which failed to improve on cidofovir. Adenovirus cleared following 2 doses of VSTs and marrow infusion from a matched unrelated donor, without incidence of graft versus host disease. T cell receptor-b sequencing demonstrated expansion of adenovirus-specific T cell fraction of the VSTs, suggesting that infusion facilitated viral clearance. This report suggests that VSTs are likely safe in the pre-HSCT period, and may be a useful bridge therapy for infants with SCID and persistent viral infections. Copyright © 2018 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Mixed Lineage Kinase 3 deficiency delays viral clearance in the lung and is associated with diminished influenza-induced cytopathic effect in infected cells

PubMed Central

Desmet, Emily A.; Hollenbaugh, Joseph A.; Sime, Patricia J.; Wright, Terry W.; Topham, David J.; Sant, Andrea J.; Takimoto, Toru; Dewhurst, Stephen; Maggirwar, Sanjay B.

2010-01-01

Influenza virus leads to acute respiratory disease resulting in seasonal epidemics and periodic pandemics. Little is known about the signaling events that regulate host defense to influenza. One particular pathway, the c-Jun amino-terminal kinase (JNK) cascade is activated following influenza infection and blocking JNK leads to enhanced viral replication. We hypothesize that Mixed Lineage Kinase 3 (MLK3), an upstream regulator of JNK, is involved in the host response to influenza. To test this, wild-type and MLK3−/− mice were infected with pathogenic strain of influenza A virus, A/PR/8/34 (PR8). Although, cellular and humoral immune responses were similar between wild-type and MLK3−/− hosts, the viral load in the lungs was comparatively higher in MLK3−/− mice at day 8 post infection. Consistent with this, MLK3−/− murine lung fibrobalsts had prolonged survival and increased virion production following infection compared to wild-type. These findings support a role for MLK3 in viral production during influenza infection. PMID:20185156

Evaluating the Use of Antibody Variable Region (Fv) Charge as a Risk Assessment Tool for Predicting Typical Cynomolgus Monkey Pharmacokinetics*

PubMed Central

Bumbaca Yadav, Daniela; Sharma, Vikas K.; Boswell, Charles Andrew; Hotzel, Isidro; Tesar, Devin; Shang, Yonglei; Ying, Yong; Fischer, Saloumeh K.; Grogan, Jane L.; Chiang, Eugene Y.; Urban, Konnie; Ulufatu, Sheila; Khawli, Leslie A.; Prabhu, Saileta; Joseph, Sean; Kelley, Robert F.

2015-01-01

The pharmacokinetic (PK) behavior of monoclonal antibodies in cynomolgus monkeys (cynos) is generally translatable to that in humans. Unfortunately, about 39% of the antibodies evaluated for PKs in cynos have fast nonspecific (or non-target-mediated) clearance (in-house data). An empirical model relating variable region (Fv) charge and hydrophobicity to cyno nonspecific clearance was developed to gauge the risk an antibody would have for fast nonspecific clearance in the monkey. The purpose of this study was to evaluate the predictability of this empirical model on cyno nonspecific clearance with antibodies specifically engineered to have either high or low Fv charge. These amino acid changes were made in the Fv region of two test antibodies, humAb4D5-8 and anti-lymphotoxin α. The humAb4D5-8 has a typical nonspecific clearance in cynos, and by making it more positively charged, the antibody acquires fast nonspecific clearance, and making it less positively charged did not impact its clearance. Anti-lymphotoxin α has fast nonspecific clearance in cynos, and making it more positively charged caused it to clear even faster, whereas making it less positively charged caused it to clear slower and within the typical range. These trends in clearance were also observed in two other preclinical species, mice and rats. The effect of modifying Fv charge on subcutaneous bioavailability was also examined, and in general bioavailability was inversely related to the direction of the Fv charge change. Thus, modifying Fv charge appears to impact antibody PKs, and the changes tended to correlate with those predicted by the empirical model. PMID:26491012

Synthetic peptides coupled to the surface of liposomes effectively induce SARS coronavirus-specific cytotoxic T lymphocytes and viral clearance in HLA-A*0201 transgenic mice.

PubMed

Ohno, Satoshi; Kohyama, Shunsuke; Taneichi, Maiko; Moriya, Osamu; Hayashi, Hidenori; Oda, Hiroshi; Mori, Masahito; Kobayashi, Akiharu; Akatsuka, Toshitaka; Uchida, Tetsuya; Matsui, Masanori

2009-06-12

We investigated whether the surface-linked liposomal peptide was applicable to a vaccine based on cytotoxic T lymphocytes (CTLs) against severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV). We first identified four HLA-A*0201-restricted CTL epitopes derived from SARS-CoV using HLA-A*0201 transgenic mice and recombinant adenovirus expressing predicted epitopes. These peptides were coupled to the surface of liposomes, and inoculated into mice. Two of the liposomal peptides were effective for peptide-specific CTL induction, and one of them was efficient for the clearance of vaccinia virus expressing epitopes of SARS-CoV, suggesting that the surface-linked liposomal peptide might offer an effective CTL-based vaccine against SARS.

Acute hepatitis B in a patient with OLT during treatment with peg-interferon and ribavirin for hepatitis C recurrence.

PubMed

Biliotti, Elisa; Zacharia, Sabu; Grieco, Stefania; Spaziante, Martina; Giusto, Michela; Merli, Manuela; Gallinaro, Valentina; Taliani, Gloria

2012-12-01

The course and outcome of acute viral hepatitis in liver transplanted patients with hepatitis C recurrence are unknown. Here we describe a patient who presented with acute hepatitis B infection while on treatment with peg-interferon and ribavirin for hepatitis C recurrence after liver transplantation. A nucleoside analogue was added (entecavir) and the patient cleared hepatitis C virus (HCV) infection and seroconverted to anti-HBs. In this case, the acute hepatitis B virus (HBV) infection might have contributed to the clearance of HCV, the concomitant immunosuppression might have lead to the slow clearance of HBV infection, and the combined antiviral therapy has helped in the resolution of both infections. Hepatitis B vaccination should be recommended in susceptible patients waiting for liver transplantation.

HDAC6 is a Regulator of CTL Function through Control of Lytic Granule Dynamics

PubMed Central

Nunez-Andrade, Norman

2016-01-01

Viral infections involve specific stress exposure that can influence the quality and average lifespan of an organism. The immune system acts through virus clearance from the organism. Many aspects of immune cells accounting for this response are still under study. Here, we review recent aspects of the molecular mechanisms involved in the delivery of the lethal hit by Cytotoxic T lymphocytes. PMID:27595053

Longitudinal peripheral blood transcriptional analysis of a patient with severe Ebola virus disease

PubMed Central

Kash, John C.; Walters, Kathie-Anne; Kindrachuk, Jason; Baxter, David; Scherler, Kelsey; Janosko, Krisztina B.; Adams, Rick D.; Herbert, Andrew S.; James, Rebekah M.; Stonier, Spencer W.; Memoli, Matthew J.; Dye, John M.; Davey, Richard T.; Chertow, Daniel S.; Taubenberger, Jeffery K.

2017-01-01

The 2013–2015 outbreak of Ebola virus disease in Guinea, Liberia, and Sierra Leone was unprecedented in the number of documented cases, but there have been few published reports on immune responses in clinical cases and their relationships with the course of illness and severity of Ebola virus disease. Symptoms of Ebola virus disease can include severe headache, myalgia, asthenia, fever, fatigue, diarrhea, vomiting, abdominal pain, and hemorrhage. Although experimental treatments are in development, there are no current U.S. Food and Drug Administration–approved vaccines or therapies. We report a detailed study of host gene expression as measured by microarray in daily peripheral blood samples collected from a patient with severe Ebola virus disease. This individual was provided with supportive care without experimental therapies at the National Institutes of Health Clinical Center from before onset of critical illness to recovery. Pearson analysis of daily gene expression signatures revealed marked gene expression changes in peripheral blood leukocytes that correlated with changes in serum and peripheral blood leukocytes, viral load, antibody responses, coagulopathy, multiple organ dysfunction, and then recovery. This study revealed marked shifts in immune and antiviral responses that preceded changes in medical condition, indicating that clearance of replicating Ebola virus from peripheral blood leukocytes is likely important for systemic viral clearance. PMID:28404864

Proviral Latency, Persistent Human Immunodeficiency Virus Infection, and the Development of Latency Reversing Agents

PubMed Central

Archin, Nancie M.

2017-01-01

Abstract Quiescent proviral genomes that persist during human immunodeficiency virus type 1 (HIV-1) infection despite effective antiretroviral therapy (ART) can fuel rebound viremia after ART interruption and is a central obstacle to the cure of HIV infection. The induction of quiescent provirus is the goal of a new class of potential therapeutics, latency reversing agents (LRAs). The discovery, development, and testing of HIV LRAs is a key part of current efforts to develop latency reversal and viral clearance strategies to eradicate established HIV infection. The development of LRAs is burdened by many uncertainties that make drug discovery difficult. The biology of HIV latency is complex and incompletely understood. Potential targets for LRAs are host factors, and the potential toxicities of host-directed therapies in individuals that are otherwise clinically stable may be unacceptable. Assays to measure latency reversal and assess the effectiveness of potential therapeutics are complex and incompletely validated. Despite these obstacles, novel LRAs are under development and beginning to enter combination testing with viral clearance strategies. It is hoped that the steady advances in the development of LRAs now being paired with emerging immunotherapeutics to clear persistently infected cells will soon allow measurable clinical advances toward an HIV cure. PMID:28520964

A Novel IL-17 Dependent Mechanism of Cross Protection: Respiratory Infection with Mycoplasma Protects Against a Secondary Listeria Infection

PubMed Central

Sieve, Amy N.; Meeks, Karen D.; Bodhankar, Sheetal; Lee, Suheung; Kolls, Jay K.; Simecka, Jerry W.; Berg, Rance E.

2009-01-01

Summary Immune responses to pathogens occur within the context of current and previous infections. Cross protection refers to the phenomena where infection with a particular pathogen provides enhanced resistance to a subsequent unrelated pathogen in an antigen independent manner. Proposed mechanisms of antigen-independent cross protection have involved the secretion of IFN-γ, which activates macrophages thus providing enhanced innate immunity against the secondary viral or bacterial pathogen. Here we provide evidence that a primary infection with the chronic respiratory pathogen, Mycoplasma pulmonis, provides a novel form of cross protection against a secondary infection with Listeria monocytogenes that is not mediated by IFN-γ, but instead relies upon IL-17 and mobilization of neutrophils. Mice infected with M. pulmonis have enhanced clearance of L. monocytogenes from the spleen and liver which is associated with increased numbers of Gr-1+CD11b+ cells and higher levels of IL-17. This enhanced clearance of L. monocytogenes was absent in mice depleted of Gr-1+ cells or in mice deficient in the IL-17 receptor. Additionally, both the IL-17 receptor and neutrophils were essential for optimal clearance of M. pulmonis. Thus, a natural component of the immune response directed against M. pulmonis was able to enhance clearance of L. monocytogenes. PMID:19180464

Dynamics of HPV viral loads reflect the treatment effect of photodynamic therapy in genital warts.

PubMed

Hu, Zhili; Liu, Lishi; Zhang, Wenjing; Liu, Hui; Li, Junpeng; Jiang, Lifen; Zeng, Kang

2018-03-01

Photodynamic therapy (PDT) has demonstrated good clinical cure rates and low recurrence rates in the treatment of genital warts. Human papillomavirus (HPV) genotypes and viral load assays can reflect the status of persistent or latent infection and serve as a predictor of infection clearance. Specimens from 41 patients with HPV infection were obtained, and the HPV genotypes and viral load were analyzed using real-time polymerase chain reaction (PCR) assays. Traditional treatment, such as radiofrequency, microwave, or surgical therapy, was used to remove the visible lesions, and then PDT treatment was performed every week. HPV DNA testing was performed at every patient visit and the frequency of PDT treatment was determined by changes in HPV viral loads. HPV viral loads decreased significantly after PDT treatment. There were significant differences in HPV viral loads between pretherapy and three or six rounds of PDT treatment. Significant differences were also observed between single and multiple type HPV infection after six rounds of PDT treatment. Patients with single type HPV infection had significantly higher rates of negative HPV DNA test results, as compared with patients with multiple infections after six rounds of PDT treatment; however, there was no difference in recurrence rates between the two groups. Dynamic monitoring of HPV genotypes and viral loads can be used to guide PDT treatment and indicate PDT treatment efficacy in eliminating HPV. Copyright © 2017 Elsevier B.V. All rights reserved.

Spontaneous hepatitis B surface antigen clearance in a long-term follow-up study of patients with chronic type B hepatitis. Lack of correlation with hepatitis C and D virus superinfection.

PubMed

Da Silva, L C; Madruga, C L; Carrilho, F J; Pinho, J R; Saéz-Alquezar, A; Santos, C; Bassit, L; Barreto, C; Fonseca, L E; Alves, V A; Leitão, R; Vianna, R; Cardoso, R A; França, A V; Gayotto, L C

1996-10-01

We investigated the frequency of HBsAg clearance and the possible role of viral superinfection in a long-term follow-up of 184 patients with chronic hepatitis B (CHB). Our subjects were 184 patients with chronic hepatitis B and the follow-up was 12-216 months (mean 66.2 +/- 53.7 months). The investigative methods used were: immunoenzymatic assays for HBV, HCV, HDV, and HIV markers; polymerase chain reaction (PCR) for HBV DNA; and liver biopsy and immunoperoxidase. During the follow-up, 20 of the 184 patients cleared serum HBsAg. A comparison of patients with persistent HBsAg(group I) and of those who cleared this marker (group II) showed a significant difference in mortality (P = 0.002) between the two groups and a tendency to a more severe exacerbation (flare) in group II (P = 0.07). Antibodies to hepatitis C and D virus as well as antibodies to HIV were equally distributed in both groups. Thirteen patients (7.9%) from group I, but none from group II, subsequently developed hepatocellular carcinoma. These results suggest that the frequency of spontaneous clearance of HBsAg during chronic HBV infection is low. No determinant factor for the clearance was found, including the presence of liver cirrhosis. Serum HBV DNA was undetectable by PCR after clearance in 16 out of 17 patients.

Genomic Loads and Genotypes of Respiratory Syncytial Virus: Viral Factors during Lower Respiratory Tract Infection in Chilean Hospitalized Infants

PubMed Central

Espinosa, Yazmín; San Martín, Camila; Torres, Alejandro A.; Farfán, Mauricio J.; Torres, Juan P.; Avadhanula, Vasanthi; Piedra, Pedro A.; Tapia, Lorena I.

2017-01-01

The clinical impact of viral factors (types and viral loads) during respiratory syncytial virus (RSV) infection is still controversial, especially regarding newly described genotypes. In this study, infants with RSV bronchiolitis were recruited to describe the association of these viral factors with severity of infection. RSV antigenic types, genotypes, and viral loads were determined from hospitalized patients at Hospital Roberto del Río, Santiago, Chile. Cases were characterized by demographic and clinical information, including days of lower respiratory symptoms and severity. A total of 86 patients were included: 49 moderate and 37 severe cases. During 2013, RSV-A was dominant (86%). RSV-B predominated in 2014 (92%). Phylogenetic analyses revealed circulation of GA2, Buenos Aires (BA), and Ontario (ON) genotypes. No association was observed between severity of infection and RSV group (p = 0.69) or genotype (p = 0.87). After a clinical categorization of duration of illness, higher RSV genomic loads were detected in infants evaluated earlier in their disease (p < 0.001) and also in infants evaluated later, but coursing a more severe infection (p = 0.04). Although types and genotypes did not associate with severity in our children, higher RSV genomic loads and delayed viral clearance in severe patients define a group that might benefit from new antiviral therapies. PMID:28335547

Nuclear core positioning system

DOEpatents

Garkisch, Hans D.; Yant, Howard W.; Patterson, John F.

1979-01-01

A structural support system for the core of a nuclear reactor which achieves relatively restricted clearances at operating conditions and yet allows sufficient clearance between fuel assemblies at refueling temperatures. Axially displaced spacer pads having variable between pad spacing and a temperature compensated radial restraint system are utilized to maintain clearances between the fuel elements. The core support plates are constructed of metals specially chosen such that differential thermal expansion produces positive restraint at operating temperatures.

Early Experience With CliniMACS Prodigy CCS (IFN-gamma) System in Selection of Virus-specific T Cells From Third-party Donors for Pediatric Patients With Severe Viral Infections After Hematopoietic Stem Cell Transplantation.

PubMed

Kállay, Krisztián; Kassa, Csaba; Réti, Marienn; Karászi, Éva; Sinkó, János; Goda, Vera; Stréhn, Anita; Csordás, Katalin; Horváth, Orsolya; Szederjesi, Attila; Tasnády, Szabolcs; Hardi, Apor; Kriván, Gergely

2018-04-01

Viral reactivation is a frequent complication of allogeneic hematopoietic stem cell transplantation especially in children. For refractory cases, rapid virus-specific T-cell therapy would be ideally implemented within a few days. Over the course of a year in our pediatric cohort of 43 allogeneic transplantation, 9 patients fulfilled criteria for virus-specific T-cell therapy. Viral infections were due to cytomegalovirus (CMV) in 3, Epstein-Barr virus (EBV) in 2, and adenovirus (AdV) in 1 case, whereas >1 virus was detected in 3 cases. Viral diseases necessitating a T-cell therapy were CMV pneumonitis and colitis, AdV enteritis and cystitis, and EBV-induced posttransplantation lymphoproliferative disease. Cells were produced by the CliniMACS Prodigy CCS (IFN-gamma) System within 24 hours after mononuclear leukapheresis. Eight patients became completely asymptomatic, whereas 7 also cleared the virus. Six patients are alive without viral illness or sequelae demonstrating viral DNA clearance in peripheral blood with a median follow-up of 535 (350-786) days. One patient with CMV pneumonitis died of respiratory insufficiency. In 2 cases the viral illness improved or cleared, however, the patients died of invasive aspergillosis. No cases of graft-versus-host disease, rejection, organ toxicity, or recurrent infection were noticed. Virus-specific T-cell therapy implemented by the CliniMACS Prodigy CCS (IFN-gamma) System is an automated, fast, safe, and probably effective way to control resistant viral diseases after pediatric hematopoietic stem cell transplantation.

The Role of Interleukin-1 and Interleukin-18 in Pro-Inflammatory and Anti-Viral Responses to Rhinovirus in Primary Bronchial Epithelial Cells

PubMed Central

Kay, Linda; Parker, Lisa C.; Sabroe, Ian; Sleeman, Matthew A.; Briend, Emmanuel; Finch, Donna K.

2013-01-01

Human Rhinovirus (HRV) is associated with acute exacerbations of chronic respiratory disease. In healthy individuals, innate viral recognition pathways trigger release of molecules with direct anti-viral activities and pro-inflammatory mediators which recruit immune cells to support viral clearance. Interleukin-1alpha (IL-1α), interleukin-1beta (IL-1β) and interleukin-18 (IL-18) have critical roles in the establishment of neutrophilic inflammation, which is commonly seen in airways viral infection and thought to be detrimental in respiratory disease. We therefore investigated the roles of these molecules in HRV infection of primary human epithelial cells. We found that all three cytokines were released from infected epithelia. Release of these cytokines was not dependent on cell death, and only IL-1β and IL-18 release was dependent on caspase-1 catalytic activity. Blockade of IL-1 but not IL-18 signaling inhibited up-regulation of pro-inflammatory mediators and neutrophil chemoattractants but had no effect on virus induced production of interferons and interferon-inducible genes, measured at both mRNA and protein level. Similar level of virus mRNA was detected with and without IL-1RI blockade. Hence IL-1 signaling, potentially involving both IL-1β and IL-1α, downstream of viral recognition plays a key role in induction of pro-inflammatory signals and potentially in recruitment and activation of immune cells in response to viral infection instigated by the epithelial cells, whilst not participating in direct anti-viral responses. PMID:23723976

Steady-state pharmacokinetics of (R)- and (S)-methadone in methadone maintenance patients

PubMed Central

Foster, David J R; Somogyi, Andrew A; Dyer, Kyle R; White, Jason M; Bochner, Felix

2000-01-01

Aims To investigate the steady-state pharmacokinetics of (R)- and (S)-methadone in a methadone maintenance population. Methods Eighteen patients recruited from a public methadone maintenance program underwent an interdosing interval pharmacokinetic study. Plasma and urine samples were collected and analysed for methadone and its major metabolite (EDDP) using stereoselective h.p.l.c. Methadone plasma protein binding was examined using ultrafiltration, and plasma α1-acid glycoprotein concentrations were quantified by radial immunoassay. Results (R)-methadone had a significantly (P < 0.05) greater unbound fraction (mean 173%) and total renal clearance (182%) compared with (S)-methadone, while maximum measured plasma concentrations (83%) and apparent partial clearance of methadone to EDDP (76%) were significantly (P < 0.001) lower. When protein binding was considered (R)-methadone plasma clearance of the unbound fraction (59%) and apparent partial intrinsic clearance to EDDP (44%) were significantly (P < 0.01) lower than for (S)-methadone, while AUCτSS, (167%) was significantly (P < 0.001) greater. There were no significant (P > 0.2) differences between the methadone enantiomers for AUCτSS, steady-state plasma clearance, trough plasma concentrations and unbound renal clearance. Patients excreted significantly (P < 0.0001) more (R)-methadone and (S)-EDDP than the corresponding enantiomers. Considerable interindividual variability was observed for the pharmacokinetic parameters, with coefficients of variation of up to 70%. Conclusions Steady-state pharmacokinetics of unbound methadone are stereoselective, and there is large interindividual variability consistent with CYP3A4 mediated metabolism to the major metabolite EDDP; the variability did not obscure a significant dose-plasma concentration relationship. Stereoselective differences in the pharmacokinetics of methadone may have important implications for pharmacokinetic-pharmacodynamic modelling but is unlikely to be important for therapeutic drug monitoring of methadone, in the setting of opioid dependence. PMID:11069437

A mouse model with age-dependent immune response and immune-tolerance for HBV infection.

PubMed

Yi, Xuerui; Yuan, Youcheng; Li, Na; Yi, Lu; Wang, Cuiling; Qi, Ying; Gong, Liang; Liu, Guangze; Kong, Xiangping

2018-02-01

Viral clearance of human HBV infection largely depends on the age of exposure. Thus, a mouse model with age-dependent immune response and immune-tolerance for HBV infection was established. HBVRag1 mice were generated by crossing Rag1 -/- mice with HBV-Tg mice. Following adoptive transfer of splenocytes adult (8-9 weeks old) and young (3 weeks old) HBVRag1 mice were named as HBVRag-ReA and HBVRag-ReY mice respectively. The biochemical parameters that were associated with viral load and immune function, as well as the histological evaluation of the liver tissues between the two mouse models were detected. The immune tolerance of HBVRag-ReY mice that were reconstituted at the early stages of life was evaluated by quantitative hepatitis B core antibody assay, adoptive transfer, and modulation of gut microbiota with the addition of antibiotics. HBVRag-ReA mice indicated apparent hepatocytes damage, clearance of HBsAg and production of HBsAb and HBcAb. HBVRag-ReY mice did not develop ALT elevation, and produced HBcAb and HBsAg. A higher number of hepatic CD8 + T and B cells promoted clearance of HBsAg in HBVRag-ReA mice following 30 days of lymphocyte transfer. In contrast to HBVRag-ReA mice, HBVRag-ReY mice exhibited higher levels of Th1/Th2 cytokines. HBVRag-ReY mice exhibited significantly higher (P < .01, approximately 10-fold) serum quantitative anti-HBc levels than HBV-Tg mice, which might be similar to the phase of immune clearance and immune tolerance in human HBV infection. Furthermore, the age-related tolerance in HBVRag-ReY mice that were sensitive to antibiotic treatment was different from that noted in HBV-Tg mice. GS-9620 could inhibit the production of HBsAg, whereas HBV vaccination could induce sustained seroconversion in HBVRag-ReY mice with low levels of HBsAg. The present study described a mouse model with age-dependent immunity and immune-tolerance for HBV infection in vivo, which may mimic chronic HBV infection in humans. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fish oil feeding delays influenza virus clearance and impairs production of interferon-gamma and virus-specific immunoglobulin A in the lungs of mice.

PubMed

Byleveld, P M; Pang, G T; Clancy, R L; Roberts, D C

1999-02-01

Ingestion of fish oil can suppress the inflammatory response to injury and may impair host resistance to infection. To investigate the effect of a diet containing fish oil on immunity to viral infection, 148 BALB/c mice were fed diets containing 3 g/100 g of sunflower oil with either 17 g/100 g of fish oil or beef tallow for 14 d before intranasal challenge with live influenza virus. At d 1 and d 5 after infection, the mice fed fish oil had higher lung viral load and lower body weight (P < 0.05). In addition to the greater viral load and weight loss at d 5 after infection, the fish oil group consumed less food (P < 0.05) while the beef tallow group was clearing the virus, had regained their preinfection weights and was returning to their preinfection food consumption. The fish oil group had impaired production of lung interferon-gamma (IFN-gamma), serum immunoglobulin (Ig) G and lung IgA-specific antibodies (all P < 0. 05) although lung IFN-alpha/beta and the relative proportions of bronchial lymph node CD4+ and CD8+ T lymphocytes did not differ between groups after infection. The present study demonstrates a delay in virus clearance in mice fed fish oil associated with reduced IFN-gamma and antibody production and a greater weight loss and suppression of appetite following influenza virus infection. However, differences observed during the course of infection did not affect the ultimate outcome as both groups cleared the virus and returned to preinfection food consumption and body weight by d 7.

Rare versus common variants in pharmacogenetics: SLCO1B1 variation and methotrexate disposition

PubMed Central

Ramsey, Laura B.; Bruun, Gitte H.; Yang, Wenjian; Treviño, Lisa R.; Vattathil, Selina; Scheet, Paul; Cheng, Cheng; Rosner, Gary L.; Giacomini, Kathleen M.; Fan, Yiping; Sparreboom, Alex; Mikkelsen, Torben S.; Corydon, Thomas J.; Pui, Ching-Hon; Evans, William E.; Relling, Mary V.

2012-01-01

Methotrexate is used to treat autoimmune diseases and malignancies, including acute lymphoblastic leukemia (ALL). Inter-individual variation in clearance of methotrexate results in heterogeneous systemic exposure, clinical efficacy, and toxicity. In a genome-wide association study of children with ALL, we identified SLCO1B1 as harboring multiple common polymorphisms associated with methotrexate clearance. The extent of influence of rare versus common variants on pharmacogenomic phenotypes remains largely unexplored. We tested the hypothesis that rare variants in SLCO1B1 could affect methotrexate clearance and compared the influence of common versus rare variants in addition to clinical covariates on clearance. From deep resequencing of SLCO1B1 exons in 699 children, we identified 93 SNPs, 15 of which were non-synonymous (NS). Three of these NS SNPs were common, with a minor allele frequency (MAF) >5%, one had low frequency (MAF 1%–5%), and 11 were rare (MAF <1%). NS SNPs (common or rare) predicted to be functionally damaging were more likely to be found among patients with the lowest methotrexate clearance than patients with high clearance. We verified lower function in vitro of four SLCO1B1 haplotypes that were associated with reduced methotrexate clearance. In a multivariate stepwise regression analysis adjusting for other genetic and non-genetic covariates, SLCO1B1 variants accounted for 10.7% of the population variability in clearance. Of that variability, common NS variants accounted for the majority, but rare damaging NS variants constituted 17.8% of SLCO1B1's effects (1.9% of total variation) and had larger effect sizes than common NS variants. Our results show that rare variants are likely to have an important effect on pharmacogenetic phenotypes. PMID:22147369

Effects of lighting illuminance levels on stair negotiation performance in individuals with visual impairment.

PubMed

Shaheen, Aliah F; Sourlas, Alexandros; Horton, Khim; McLean, Christopher; Ewins, David; Gould, David; Ghoussayni, Salim

2018-04-01

Stair-related falls of older people cause a substantial financial and social burden. Deterioration of the visual system amongst other factors put older people at a high risk of falling. Improved lighting is often recommended. The aim of this study was to investigate the effect of lighting illuminance on stair negotiation performance in older individuals with visual impairment. Eleven participants aged 60 or over with a vision of 6/18 or worse ascended and descended a staircase under: 50 lx, 100 lx, 200 lx, 300 lx and distributed 200 lx lighting. A motion capture system was used to measure movements of the lower limb. Clearance, clearance variability, temporal and spatial parameters and joint/segment kinematics were computed. There was no effect on clearance or clearance variability. Participants had lower speed, cadence, increased cycle time and stance time in the 50 lx compared to 300 lx and distributed 200 lx lighting in descent. The minimum hip angle in ascent was increased in the 200 lx lighting. Clearance was found to be moderately correlated with balance scores. Individuals with visual impairment adopt precautionary gait in dim lighting conditions. This does not always result in improvements in the parameters associated with risk of falling (e.g. clearance). Copyright © 2018 Elsevier Ltd. All rights reserved.

An Investigation of Flight Deck Data Link in the Terminal Area

NASA Technical Reports Server (NTRS)

Martin, Lynne; Lozito, Sandra; Kaneshige, John; Dulchinos, Vicki; Sharma, Shivanjli

2013-01-01

The Next Generation Air Transportation System (NextGen) and Europe's Single European Sky ATM Research (SESAR) concepts require an increased use of trajectory-based operations, including extensive strategic air traffic control clearances. The clearances are lengthy and complex, which necessitate data link communications to allow for message permanence and integration into the autoflight systems (i.e., autoload capability). This paper examines the use of flight deck data link communications for strategic and tactical clearance usage in the terminal area. A human-in-the-loop simulation was conducted using a high-fidelity flight deck simulator, with ten commercial flight crews as participants. Data were collected from six flight scenarios in the San Francisco terminal airspace. The variables of interest were ATC message modality (voice v. data link), temporal quality of the message (tactical v. strategic) and message length. Dependent variables were message response times, communication clarifications, communication-related errors, and pilot workload. Response time results were longer in data link compared to voice, a finding that has been consistently revealed in a number of other simulations [1]. In addition, strategic clearances and longer messages resulted in a greater number of clarifications and errors, suggesting an increase in uncertainty of message interpretation for the flight crews when compared to tactical clearances. The implications for strategic and compound clearance usage in NextGen and SESAR are discussed

Achieving a Successful Scale-Down Model and Optimized Economics through Parvovirus Filter Validation using Purified TrueSpikeTM Viruses.

PubMed

De Vilmorin, Philippe; Slocum, Ashley; Jaber, Tareq; Schaefer, Oliver; Ruppach, Horst; Genest, Paul

2015-01-01

This article describes a four virus panel validation of EMD Millipore's (Bedford, MA) small virus-retentive filter, Viresolve® Pro, using TrueSpike(TM) viruses for a Biogen Idec process intermediate. The study was performed at Charles River Labs in King of Prussia, PA. Greater than 900 L/m(2) filter throughput was achieved with the approximately 8 g/L monoclonal antibody feed. No viruses were detected in any filtrate samples. All virus log reduction values were between ≥3.66 and ≥5.60. The use of TrueSpike(TM) at Charles River Labs allowed Biogen Idec to achieve a more representative scaled-down model and potentially reduce the cost of its virus filtration step and the overall cost of goods. The body of data presented here is an example of the benefits of following the guidance from the PDA Technical Report 47, The Preparation of Virus Spikes Used for Viral Clearance Studies. The safety of biopharmaceuticals is assured through the use of multiple steps in the purification process that are capable of virus clearance, including filtration with virus-retentive filters. The amount of virus present at the downstream stages in the process is expected to be and is typically low. The viral clearance capability of the filtration step is assessed in a validation study. The study utilizes a small version of the larger manufacturing size filter, and a large, known amount of virus is added to the feed prior to filtration. Viral assay before and after filtration allows the virus log reduction value to be quantified. The representativeness of the small-scale model is supported by comparing large-scale filter performance to small-scale filter performance. The large-scale and small-scale filtration runs are performed using the same operating conditions. If the filter performance at both scales is comparable, it supports the applicability of the virus log reduction value obtained with the small-scale filter to the large-scale manufacturing process. However, the virus preparation used to spike the feed material often contains impurities that contribute adversely to virus filter performance in the small-scale model. The added impurities from the virus spike, which are not present at manufacturing scale, compromise the scale-down model and put into question the direct applicability of the virus clearance results. Another consequence of decreased filter performance due to virus spike impurities is the unnecessary over-sizing of the manufacturing system to match the low filter capacity observed in the scale-down model. This article describes how improvements in mammalian virus spike purity ensure the validity of the log reduction value obtained with the scale-down model and support economically optimized filter usage. © PDA, Inc. 2015.

Flow fields behind a variable-area nozzle for radial turbines

NASA Astrophysics Data System (ADS)

Hayami, Hiroshi; Hyun, Yong-Ik; Senoo, Yasutoshi; Yamaguchi, Michiteru

The flow fields behind a variable-area nozzle for radial turbines were measured in detail using a three-hole cobra probe in 15 cases, which are a combination of three nozzle throat areas (0.8, 1.0, and 1.4 times the rated area) and five values of the tip-clearance to blade-height ratio (between 0.0 to 0.099). The flow fields at different tip clearances are presented in contour maps, and the pitch mean values are discussed as spanwise distributions of total pressure loss, flow angle, and radial and tangential velocity components. It is shown that the intensity of swirl behind the nozzle is decreased and the pressure loss is increased with the tip clearance, and the effect is magnified as the blade loading is higher.

Application of a Pharmacokinetic Model of Metformin Clearance in a Population with Acute Myeloid Leukemia.

PubMed

Ceacareanu, Alice C; Brown, Geoffrey W; Moussa, Hoda A; Wintrob, Zachary A P

2018-01-01

We aimed to estimate the metformin-associated lactic acidosis (MALA) risk by assessing retrospectively the renal clearance variability and applying a pharmacokinetic (PK) model of metformin clearance in a population diagnosed with acute myeloid leukemia (AML) and diabetes mellitus (DM). All adults with preexisting DM and newly diagnosed AML at Roswell Park Cancer Institute were reviewed (January 2003-December 2010, n = 78). Creatinine clearance (CrCl) and total body weight distributions were used in a two-compartment PK model adapted for multiple dosing and modified to account for actual intra- and inter-individual variability. Based on this renal function variability evidence, 1000 PK profiles were simulated for multiple metformin regimens with the resultant PK profiles being assessed for safe CrCl thresholds. Metformin 500 mg up to three times daily was safe for all simulated profiles with CrCl ≥25 mL/min. Furthermore, the estimated overall MALA risk was below 10%, remaining under 5% for 500 mg given once daily. CrCl ≥65.25 mL/min was safe for administration in any of the tested regimens (500 mg or 850 mg up to three times daily or 1000 mg up to twice daily). PK simulation-guided prescribing can maximize metformin's beneficial effects on cancer outcomes while minimizing MALA risk.

Multi-dose Romidepsin Reactivates Replication Competent SIV in Post-antiretroviral Rhesus Macaque Controllers

PubMed Central

Policicchio, Benjamin B.; Xu, Cuiling; Brocca-Cofano, Egidio; Raehtz, Kevin D.; He, Tianyu; Ma, Dongzhu; Li, Hui; Haret-Richter, George S.; Dunsmore, Tammy; Trichel, Anita; Mellors, John W.; Hahn, Beatrice H.; Shaw, George M.; Ribeiro, Ruy M.; Pandrea, Ivona; Apetrei, Cristian

2016-01-01

Viruses that persist despite seemingly effective antiretroviral treatment (ART) and can reinitiate infection if treatment is stopped preclude definitive treatment of HIV-1 infected individuals, requiring lifelong ART. Among strategies proposed for targeting these viral reservoirs, the premise of the “shock and kill” strategy is to induce expression of latent proviruses [for example with histone deacetylase inhibitors (HDACis)] resulting in elimination of the affected cells through viral cytolysis or immune clearance mechanisms. Yet, ex vivo studies reported that HDACis have variable efficacy for reactivating latent proviruses, and hinder immune functions. We developed a nonhuman primate model of post-treatment control of SIV through early and prolonged administration of ART and performed in vivo reactivation experiments in controller RMs, evaluating the ability of the HDACi romidepsin (RMD) to reactivate SIV and the impact of RMD treatment on SIV-specific T cell responses. Ten RMs were IV-infected with a SIVsmmFTq transmitted-founder infectious molecular clone. Four RMs received conventional ART for >9 months, starting from 65 days post-infection. SIVsmmFTq plasma viremia was robustly controlled to <10 SIV RNA copies/mL with ART, without viral blips. At ART cessation, initial rebound viremia to ~106 copies/mL was followed by a decline to < 10 copies/mL, suggesting effective immune control. Three post-treatment controller RMs received three doses of RMD every 35–50 days, followed by in vivo experimental depletion of CD8+ cells using monoclonal antibody M-T807R1. RMD was well-tolerated and resulted in a rapid and massive surge in T cell activation, as well as significant virus rebounds (~104 copies/ml) peaking at 5–12 days post-treatment. CD8+ cell depletion resulted in a more robust viral rebound (107 copies/ml) that was controlled upon CD8+ T cell recovery. Our results show that RMD can reactivate SIV in vivo in the setting of post-ART viral control. Comparison of the patterns of virus rebound after RMD administration and CD8+ cell depletion suggested that RMD impact on T cells is only transient and does not irreversibly alter the ability of SIV-specific T cells to control the reactivated virus. PMID:27632364

Paracetamol pharmacokinetics and metabolism in young women.

PubMed

Allegaert, Karel; Peeters, Mariska Y; Beleyn, Bjorn; Smits, Anne; Kulo, Aida; van Calsteren, Kristel; Deprest, Jan; de Hoon, Jan; Knibbe, Catherijne A J

2015-11-13

There is relevant between individual variability in paracetamol clearance in young women. In this pooled study, we focused on the population pharmacokinetic profile of intravenous paracetamol metabolism and its covariates in young women. Population PK parameters using non-linear mixed effect modelling were estimated in a pooled dataset of plasma and urine PK studies in 69 young women [47 at delivery, 8/47 again 10-15 weeks after delivery (early postpartum), and 7/8 again 1 year after delivery (late postpartum), 22 healthy female volunteers with or without oral contraceptives]. Population PK parameters were estimated based on 815 plasma samples and 101 urine collections. Compared to healthy female volunteers (reference group) not on oral contraceptives, being at delivery was the most significant covariate for clearance to paracetamol glucuronide (Factor = 2.03), while women in early postpartum had decreased paracetamol glucuronidation clearance (Factor = 0.55). Women on contraceptives showed increased paracetamol glucuronidation clearance (Factor = 1.46). The oestradiol level did not further affect this model. Being at delivery did not prove significant for clearance to paracetamol sulphate, but was higher in pregnant women who delivered preterm (<37 weeks, Factor = 1.34) compared to term delivery and non-pregnant women. Finally, clearance of unchanged paracetamol was dependent on urine flow rate. Compared to healthy female volunteers not on oral contraceptives, urine paracetamol glucuronidation elimination in young women is affected by pregnancy (higher), early postpartum (lower) or exposure to oral contraceptives (higher), resulting in at least a two fold variability in paracetamol clearance in young women.

Polymorphisms in CYP1A1 and CYP3A5 Genes Contribute to the Variability in Granisetron Clearance and Exposure in Pregnant Women with Nausea and Vomiting.

PubMed

Bustos, Martha L; Zhao, Yang; Chen, Huijun; Caritis, Steve N; Venkataramanan, Raman

2016-12-01

Nausea and vomiting affect up to 90% of pregnant women. Granisetron is a potent and highly selective serotonin receptor antagonist and is an effective antiemetic. Findings from a prior study in pregnant women demonstrated a large interindividual variability in granisetron exposure. Granisetron is primarily metabolized by the cytochrome P450 (CYP) enzymes CYP1A1 and CYP3A and is likely a substrate of the ABCB1 transporter. Single-nucleotide polymorphisms (SNPs) in CYP3A, CYP1A1, and ABCB1 can alter drug metabolism. This study evaluated the influence of polymorphisms in CYP3A4, CYP3A5, CYP1A1, and ABCB1 on the pharmacokinetic properties of granisetron in pregnant women. The study enrolled 16 pregnant women (gestational age of 12-19 wks). All patients had nausea and vomiting and were treated with granisetron 1 mg. Granisetron plasma concentrations were determined using liquid chromatography tandem-mass spectrometry. The patients' genotype was determined using TaqMan SNP Genotyping Assays. The Hardy-Weinberg equilibrium was assessed by comparing observed and expected genotype frequencies, using the exact test. Intravenous granisetron clearance was used as the dependent variable for analysis of associations. Of 16 patients, 25% were homozygous for the allele variant CYP3A5*3 and had a significantly lower granisetron clearance and increased area under the plasma concentration-versus-time curve (AUC) compared with nonhomozygous patients. Approximately one-third of patients (n=5) were carriers for the allele variant CYP1A1*2A and had a significantly higher granisetron clearance and decreased AUC. We did not find significant differences in the AUC or clearance for any SNPs in CYP3A4 and ABCB1 genes. Polymorphisms in CYP3A5 and CYP1A1 account for some of the variability in systemic clearance and exposure of granisetron in pregnant women. © 2016 Pharmacotherapy Publications, Inc.

Large Variations in HIV-1 Viral Load Explained by Shifting-Mosaic Metapopulation Dynamics

PubMed Central

Lythgoe, Katrina A.; Blanquart, François

2016-01-01

The viral population of HIV-1, like many pathogens that cause systemic infection, is structured and differentiated within the body. The dynamics of cellular immune trafficking through the blood and within compartments of the body has also received wide attention. Despite these advances, mathematical models, which are widely used to interpret and predict viral and immune dynamics in infection, typically treat the infected host as a well-mixed homogeneous environment. Here, we present mathematical, analytical, and computational results that demonstrate that consideration of the spatial structure of the viral population within the host radically alters predictions of previous models. We study the dynamics of virus replication and cytotoxic T lymphocytes (CTLs) within a metapopulation of spatially segregated patches, representing T cell areas connected by circulating blood and lymph. The dynamics of the system depend critically on the interaction between CTLs and infected cells at the within-patch level. We show that for a wide range of parameters, the system admits an unexpected outcome called the shifting-mosaic steady state. In this state, the whole body’s viral population is stable over time, but the equilibrium results from an underlying, highly dynamic process of local infection and clearance within T-cell centers. Notably, and in contrast to previous models, this new model can explain the large differences in set-point viral load (SPVL) observed between patients and their distribution, as well as the relatively low proportion of cells infected at any one time, and alters the predicted determinants of viral load variation. PMID:27706164

Understanding MHC Class I Presentation of Viral Antigens by Human Dendritic Cells as a Basis for Rational Design of Therapeutic Vaccines

PubMed Central

van Montfoort, Nadine; van der Aa, Evelyn; Woltman, Andrea M.

2014-01-01

Effective viral clearance requires the induction of virus-specific CD8+ cytotoxic T lymphocytes (CTL). Since dendritic cells (DC) have a central role in initiating and shaping virus-specific CTL responses, it is important to understand how DC initiate virus-specific CTL responses. Some viruses can directly infect DC, which theoretically allow direct presentation of viral antigens to CTL, but many viruses target other cells than DC and thus the host depends on the cross-presentation of viral antigens by DC to activate virus-specific CTL. Research in mouse models has highly enhanced our understanding of the mechanisms underlying cross-presentation and the dendritic cells (DC) subsets involved, however, these results cannot be readily translated toward the role of human DC in MHC class I-antigen presentation of human viruses. Here, we summarize the insights gained in the past 20 years on MHC class I presentation of viral antigen by human DC and add to the current debate on the capacities of different human DC subsets herein. Furthermore, possible sources of viral antigens and essential DC characteristics for effective induction of virus-specific CTL are evaluated. We conclude that cross-presentation is not only an efficient mechanism exploited by DC to initiate immunity to viruses that do not infect DC but also to viruses that do infect DC, because cross-presentation has many conceptual advantages and bypasses direct immune modulatory effects of the virus on its infected target cells. Since knowledge on the mechanism of viral antigen presentation and the preferred DC subsets is crucial for rational vaccine design, the obtained insights are very instrumental for the development of effective anti-viral immunotherapy. PMID:24795724

Virologic and Immunologic Characteristics in Mature Ducks with Acute Duck Hepatitis A Virus 1 Infection.

PubMed

Mao, Sai; Wang, Mingshu; Ou, Xumin; Sun, Di; Cheng, Anchun; Zhu, Dekang; Chen, Shun; Jia, Renyong; Liu, Mafeng; Sun, Kunfeng; Yang, Qiao; Wu, Ying; Zhao, Xinxin; Chen, Xiaoyue

2017-01-01

Duck hepatitis A virus 1 (DHAV-1) infection in mature ducks has previously been proposed as a small-animal model for human hepatitis A. However, basic research on the outcome of DHAV-1 infection in mature ducks is limited. Here, we examined the course of viremia, the characteristics of antibody responses, and the profiles of plasma cytokines in mature ducks infected with DHAV-1. During the course of infection, the viremia was detectable soon after infection and persisted for 196 days, however, the ducks presented as clinically asymptomatic. Specific and timely immunoglobulin G (IgG), IgM, and IgA1 responses were elicited. At the same time, extensive inhibition of viral replication was observed with increasing IgG concentration. With respect to pattern-recognition receptors, TLR-7 was mainly involved in triggering the innate defense against the DHAV-1 infection. In addition, plasma immune analytes were measured and were determined to have bidirectional roles in virus clearance. It was concluded that DHAV-1 spreads quickly in blood. The spontaneous clearance of DHAV-1 during asymptomatic infection in mature ducks depends on the cooperation of timely antibody responses and alert innate immune responses. Moreover, the delayed clearance may be associated with a weak interferon-γ-producing CD8+ T cell response. This study allows us to reveal the mechanism of clearance and persistence of DHAV-1 infection in mature ducks. We anticipate that it will provide a basis for future studies focused on defining the nature mechanisms involved in the clearance and persistence of human hepatitis virus.

Interleukin28B and inosine triphosphatase help to personalize hepatitis C treatment.

PubMed

Tanaka, Yasuhito

2011-01-01

In the therapy using a combination of pegylated interferon-α and ribavirin (PEG-IFN/RBV) for chronic hepatitis C (CHC), approximately 50% of CHC patients infected with high viremia of HCV genotype 1 reached sustained viral response. The recent discovery revealed by a genome-wide association study technology provides the unexpected role of IL28B and inosine triphosphatase (ITPA) in HCV infection. The former single nucleotide polymorphisms (SNPs) around the IL28B gene could improve the diagnostics on the prediction of spontaneous clearance and the response to anti-HCV treatment, suggesting that these findings could be strong evidence to enhance the development of a novel therapeutic strategy and the basic study of IFN-λs. Interestingly, the discovered IL28B SNPs revealed the enigma that the viral clearance rate was dependent on ethnicity. The latter functional SNP in ITPA locus was the most significant SNP associated with RBV-induced anemia as well as IFN-induced thrombocytopenia. Note that severe Hb decline, which is mainly found in ITPA-CC patients, was inversely correlated with platelet reduction, contributing to an association between severe anemia and relative reactive increase in platelet count. These data may provide a valuable pharmacogenetic diagnostic tool for tailoring PEG-IFN/RBV dosing to minimize drug-induced adverse events and for further optimization of clinical anti-HCV chemotherapeutics. Copyright © 2011 S. Karger AG, Basel.

Quantitative Temporal in Vivo Proteomics Deciphers the Transition of Virus-Driven Myeloid Cells into M2 Macrophages

PubMed Central

2017-01-01

Myeloid cells play a central role in the context of viral eradication, yet precisely how these cells differentiate throughout the course of acute infections is poorly understood. In this study, we have developed a novel quantitative temporal in vivo proteomics (QTiPs) platform to capture proteomic signatures of temporally transitioning virus-driven myeloid cells directly in situ, thus taking into consideration host–virus interactions throughout the course of an infection. QTiPs, in combination with phenotypic, functional, and metabolic analyses, elucidated a pivotal role for inflammatory CD11b+, Ly6G–, Ly6Chigh-low cells in antiviral immune response and viral clearance. Most importantly, the time-resolved QTiPs data set showed the transition of CD11b+, Ly6G–, Ly6Chigh-low cells into M2-like macrophages, which displayed increased antigen-presentation capacities and bioenergetic demands late in infection. We elucidated the pivotal role of myeloid cells in virus clearance and show how these cells phenotypically, functionally, and metabolically undergo a timely transition from inflammatory to M2-like macrophages in vivo. With respect to the growing appreciation for in vivo examination of viral–host interactions and for the role of myeloid cells, this study elucidates the use of quantitative proteomics to reveal the role and response of distinct immune cell populations throughout the course of virus infection. PMID:28768414

Longitudinal peripheral blood transcriptional analysis of a patient with severe Ebola virus disease.

PubMed

Kash, John C; Walters, Kathie-Anne; Kindrachuk, Jason; Baxter, David; Scherler, Kelsey; Janosko, Krisztina B; Adams, Rick D; Herbert, Andrew S; James, Rebekah M; Stonier, Spencer W; Memoli, Matthew J; Dye, John M; Davey, Richard T; Chertow, Daniel S; Taubenberger, Jeffery K

2017-04-12

The 2013-2015 outbreak of Ebola virus disease in Guinea, Liberia, and Sierra Leone was unprecedented in the number of documented cases, but there have been few published reports on immune responses in clinical cases and their relationships with the course of illness and severity of Ebola virus disease. Symptoms of Ebola virus disease can include severe headache, myalgia, asthenia, fever, fatigue, diarrhea, vomiting, abdominal pain, and hemorrhage. Although experimental treatments are in development, there are no current U.S. Food and Drug Administration-approved vaccines or therapies. We report a detailed study of host gene expression as measured by microarray in daily peripheral blood samples collected from a patient with severe Ebola virus disease. This individual was provided with supportive care without experimental therapies at the National Institutes of Health Clinical Center from before onset of critical illness to recovery. Pearson analysis of daily gene expression signatures revealed marked gene expression changes in peripheral blood leukocytes that correlated with changes in serum and peripheral blood leukocytes, viral load, antibody responses, coagulopathy, multiple organ dysfunction, and then recovery. This study revealed marked shifts in immune and antiviral responses that preceded changes in medical condition, indicating that clearance of replicating Ebola virus from peripheral blood leukocytes is likely important for systemic viral clearance. Copyright © 2017, American Association for the Advancement of Science.

Off-design performance loss model for radial turbines with pivoting, variable-area stators

NASA Technical Reports Server (NTRS)

Meitner, P. L.; Glassman, A. J.

1980-01-01

An off-design performance loss model was developed for variable stator (pivoted vane), radial turbines through analytical modeling and experimental data analysis. Stator loss is determined by a viscous loss model; stator vane end-clearance leakage effects are determined by a clearance flow model. Rotor loss coefficient were obtained by analyzing the experimental data from a turbine rotor previously tested with six stators having throat areas from 20 to 144 percent of design area and were correlated with stator-to-rotor throat area ratio. An incidence loss model was selected to obtain best agreement with experimental results. Predicted turbine performance is compared with experimental results for the design rotor as well as with results for extended and cutback versions of the rotor. Sample calculations were made to show the effects of stator vane end-clearance leakage.

Reduced-dose telaprevir-based triple antiviral therapy for recurrent hepatitis C after living donor liver transplantation.

PubMed

Ikegami, Toru; Yoshizumi, Tomoharu; Kato, Masaki; Yamamoto, Satomi; Fukuhara, Takasuke; Matsuura, Yoshiharu; Nakamura, Shota; Itoh, Shinji; Shirabe, Ken; Maehara, Yoshihiko

2014-11-15

The feasibility of telaprevir-based triple therapy for recurrent hepatitis C after liver transplantation (LT) has not been evaluated in Asian patients. Eleven Japanese patients received reduced-dose telaprevir (1500 mg) and adjusted-dose cyclosporine after LT. Six patients were nonresponders and three were transient responders to dual therapy. Rapid viral response, early viral response, end of treatment response, and sustained viral response were achieved in 27.3%, 90.9%, 90.9%, and 81.8% of patients, respectively. One patient had viral breakthrough at week 8 with a T54A mutation in NS3. Deep sequence analysis showed that the T54A mutation reverted to wild-type after stopping telaprevir administration. Seven patients developed severe anemia, and six received blood transfusions (4-20 U). Their hemoglobin and estimated glomerular filtration rate remained significantly lower than pretreatment values at 36 weeks after treatment. Four patients developed plasma cell hepatitis after completing telaprevir treatment, and it was treated by increasing the immunosuppressants. Although the cyclosporine level/dose ratio was 2.7 times higher at week 4 than before treatment, it was 0.7 times lower at week 36. Reduced-dosed telaprevir-based triple antiviral therapy achieved a high viral clearance rate in Japanese patients after LT. Major adverse events included severe anemia, renal dysfunction, and plasma cell hepatitis.

Acute Mucociliary Clearance Response to Aerobic Exercise in Smokers.

PubMed

Ramos, Ercy M C; Vanderlei, Luiz Carlos M; Ito, Juliana T; Lima, Fabiano F; Rodrigues, Fernanda M M; Manzano, Beatriz M; Fernandes, Rômulo A; Cecílio, Michel J; Toledo-Arruda, Alessandra C; Ramos, Dionei

2015-11-01

Mucociliary clearance is the main defense mechanism of the respiratory system, and it is influenced by several stimuli, including aerobic exercise and cigarette smoking. We evaluated the acute response of mucociliary clearance to aerobic exercise in smokers and nonsmokers compared with that found after acute smoking and smoking combined with exercise. Also, we investigated whether there was a correlation between mucociliary clearance and the autonomic nervous system under these conditions. Twenty-one smokers were evaluated for mucociliary clearance by saccharin transit time (STT), and the response of the autonomic nervous system was evaluated by heart rate variability after aerobic exercise, after exercise followed by smoking, after acute smoking, and after rest. For comparison, 17 nonsmokers were also assessed during exercise. Repeated-measures analysis of variance with the Tukey test or the Friedman test followed by the Dunn test was used to evaluate the STT, autonomic response, and other variables to exercise and/or smoking in smokers. A paired t test or Wilcoxon test was used to analyze responses to exercise in nonsmokers. Correlations were evaluated using Pearson or Spearman coefficients. The STT was reduced after exercise in both groups, with similar responses between them. Other stimuli also reduced the STT. The STT showed a negative correlation with sympathetic activity in smokers and a positive correlation with the parasympathetic system in nonsmokers. Although impaired in smokers, mucociliary clearance responded to the stimulus of exercise, as demonstrated by similar STTs compared with nonsmokers. This response was correlated with the autonomic nervous system in both groups. In smokers, mucociliary clearance also responded to the stimuli of smoking and exercise followed by smoking. Copyright © 2015 by Daedalus Enterprises.

Impaired Urine Dilution Capability in HIV Stable Patients

PubMed Central

Belloso, Waldo H.; de Paz Sierra, Mariana; Navarro, Matilde; Sanchez, Marisa L.; Perelsztein, Ariel G.; Musso, Carlos G.

2014-01-01

Renal disease is a well-recognized complication among patients with HIV infection. Viral infection itself and the use of some antiretroviral drugs contribute to this condition. The thick ascending limb of Henle's loop (TALH) is the tubule segment where free water clearance is generated, determining along with glomerular filtration rate the kidney's ability to dilute urine. Objective. We analyzed the function of the proximal tubule and TALH in patients with HIV infection receiving or not tenofovir-containing antiretroviral treatment in comparison with healthy seronegative controls, by applying a tubular physiological test, hyposaline infusion test (Chaimowitz' test). Material & Methods. Chaimowitz' test was performed on 20 HIV positive volunteers who had normal renal functional parameters. The control group included 10 healthy volunteers. Results. After the test, both HIV groups had a significant reduction of serum sodium and osmolarity compared with the control group. Free water clearance was lower and urine osmolarity was higher in both HIV+ groups. Proximal tubular function was normal in both studied groups. Conclusion. The present study documented that proximal tubule sodium reabsorption was preserved while free water clearance and maximal urine dilution capability were reduced in stable HIV patients treated or not with tenofovir. PMID:24800076

Application of a Pharmacokinetic Model of Metformin Clearance in a Population with Acute Myeloid Leukemia

PubMed Central

Ceacareanu, Alice C.; Brown, Geoffrey W.; Moussa, Hoda A.; Wintrob, Zachary A. P.

2018-01-01

Objective: We aimed to estimate the metformin-associated lactic acidosis (MALA) risk by assessing retrospectively the renal clearance variability and applying a pharmacokinetic (PK) model of metformin clearance in a population diagnosed with acute myeloid leukemia (AML) and diabetes mellitus (DM). Methods: All adults with preexisting DM and newly diagnosed AML at Roswell Park Cancer Institute were reviewed (January 2003–December 2010, n = 78). Creatinine clearance (CrCl) and total body weight distributions were used in a two-compartment PK model adapted for multiple dosing and modified to account for actual intra- and inter-individual variability. Based on this renal function variability evidence, 1000 PK profiles were simulated for multiple metformin regimens with the resultant PK profiles being assessed for safe CrCl thresholds. Findings: Metformin 500 mg up to three times daily was safe for all simulated profiles with CrCl ≥25 mL/min. Furthermore, the estimated overall MALA risk was below 10%, remaining under 5% for 500 mg given once daily. CrCl ≥65.25 mL/min was safe for administration in any of the tested regimens (500 mg or 850 mg up to three times daily or 1000 mg up to twice daily). Conclusion: PK simulation-guided prescribing can maximize metformin's beneficial effects on cancer outcomes while minimizing MALA risk. PMID:29755998

Cellular inhibitor of apoptosis proteins prevent clearance of hepatitis B virus.

PubMed

Ebert, Gregor; Preston, Simon; Allison, Cody; Cooney, James; Toe, Jesse G; Stutz, Michael D; Ojaimi, Samar; Scott, Hamish W; Baschuk, Nikola; Nachbur, Ueli; Torresi, Joseph; Chin, Ruth; Colledge, Danielle; Li, Xin; Warner, Nadia; Revill, Peter; Bowden, Scott; Silke, John; Begley, C Glenn; Pellegrini, Marc

2015-05-05

Hepatitis B virus (HBV) infection can result in a spectrum of outcomes from immune-mediated control to disease progression, cirrhosis, and liver cancer. The host molecular pathways that influence and contribute to these outcomes need to be defined. Using an immunocompetent mouse model of chronic HBV infection, we identified some of the host cellular and molecular factors that impact on infection outcomes. Here, we show that cellular inhibitor of apoptosis proteins (cIAPs) attenuate TNF signaling during hepatitis B infection, and they restrict the death of infected hepatocytes, thus allowing viral persistence. Animals with a liver-specific cIAP1 and total cIAP2 deficiency efficiently control HBV infection compared with WT mice. This phenotype was partly recapitulated in mice that were deficient in cIAP2 alone. These results indicate that antagonizing the function of cIAPs may promote the clearance of HBV infection.

Toe spatiotemporal differences between transition steps when ascending shorter flight stairways of different heights.

PubMed

Ajisafe, Toyin; Wu, Jianhua; Geil, Mark

2017-03-01

Studies have typically treated the first and second floor-to-stair transition steps (TS1 and TS2) as one stride. However, because the foot is devoid of plantar cutaneous input from the stair surface at TS1, these steps may have different toe spatiotemporal profiles, and resultantly, different susceptibilities to a trip and/or a fall. This study compared vertical toe clearance, forward velocity, and their respective variability magnitudes between TS1 and TS2 when ascending stairs of different heights. Twenty young adults (seven males and 13 females) (21.68 ± 2.49 years; 169.70 ± 9.56 cm; 63.91 ± 9.62 kg) negotiated an intervening three-step staircase placed midpoint on a 10 m walkway. There were three stair heights: low stairs (LS), medium stairs (MS), and high stairs (HS). Vertical toe clearance, forward velocity, and their variability magnitudes were calculated. Vertical toe clearance was only higher (P < 0.05) at TS1 than TS2 in the medium and high stairs. Vertical toe clearance was more variable (P < 0.05) in the low compared to medium stairs. Also, forward toe velocity was greater at TS1 than TS2, but was lower in the medium and high stairs. The locomotor system appeared cautious by exaggerating vertical toe clearance at both TS1 and TS2 only in low stairs, possibly due to higher forward toe velocity. If the exaggeration strategy consistently persists, this finding may suggest decreased trip or fall risk at both TS1 and TS2 only when transitioning onto low stairs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influenza A induced cellular signal transduction pathways

PubMed Central

Michael, Paul; Brabant, Danielle; Bleiblo, Farag; Ramana, Chilakamarti V.; Rutherford, Michael; Khurana, Sandhya; Tai, T.C.; Kumar, Anand

2013-01-01

Influenza A is a negative sense single stranded RNA virus that belongs to the Orthomyxoviridae Family. This enveloped virus contains 8 segments of viral RNA which encodes 11 viral proteins. Influenza A infects humans and is the causative agent of the flu. Annually it infects approximately 5% to 15% of the population world wide and results in an estimated 250,000 to 500,000 deaths a year. The nature of influenza A replication results in a high mutation rate which results in the need for seasonal vaccinations. In addition the zoonotic nature of the influenza virus allows for recombination of viral segments from different strains creating new variants that have not been encountered before. This type of mutation is the method by which pandemic strains of the flu arises. Infection with influenza results in a respiratory illness that for most individuals is self limiting. However in susceptible populations which include individuals with pre-existing pulmonary or cardiac conditions, the very young and the elderly fatal complications may arise. The most serious of these is the development of viral pneumonia which may be accompanied by secondary bacterial infections. Progression of pneumonia leads to the development of acute respiratory distress syndrome (ARDS), acute lung injury (ALI) and potentially respiratory failure. This progression is a combined effect of the host immune system response to influenza infection and the viral infection itself. This review will focus on molecular aspects of viral replication in alveolar cells and their response to infection. The response of select innate immune cells and their contribution to viral clearance and lung epithelial damage will also be discussed. Molecular aspects of antiviral response in the cells in particular the protein kinase RNA dependent response, and the oligoadenylate synthetase RNAse L system in relation to influenza infection. PMID:23977434

Human induced pluripotent stem cell-derived cardiomyocytes as an in vitro model for coxsackievirus B3-induced myocarditis and antiviral drug screening platform.

PubMed

Sharma, Arun; Marceau, Caleb; Hamaguchi, Ryoko; Burridge, Paul W; Rajarajan, Kuppusamy; Churko, Jared M; Wu, Haodi; Sallam, Karim I; Matsa, Elena; Sturzu, Anthony C; Che, Yonglu; Ebert, Antje; Diecke, Sebastian; Liang, Ping; Red-Horse, Kristy; Carette, Jan E; Wu, Sean M; Wu, Joseph C

2014-08-29

Viral myocarditis is a life-threatening illness that may lead to heart failure or cardiac arrhythmias. A major causative agent for viral myocarditis is the B3 strain of coxsackievirus, a positive-sense RNA enterovirus. However, human cardiac tissues are difficult to procure in sufficient enough quantities for studying the mechanisms of cardiac-specific viral infection. This study examined whether human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) could be used to model the pathogenic processes of coxsackievirus-induced viral myocarditis and to screen antiviral therapeutics for efficacy. hiPSC-CMs were infected with a luciferase-expressing coxsackievirus B3 strain (CVB3-Luc). Brightfield microscopy, immunofluorescence, and calcium imaging were used to characterize virally infected hiPSC-CMs for alterations in cellular morphology and calcium handling. Viral proliferation in hiPSC-CMs was quantified using bioluminescence imaging. Antiviral compounds including interferonβ1, ribavirin, pyrrolidine dithiocarbamate, and fluoxetine were tested for their capacity to abrogate CVB3-Luc proliferation in hiPSC-CMs in vitro. The ability of these compounds to reduce CVB3-Luc proliferation in hiPSC-CMs was consistent with reported drug effects in previous studies. Mechanistic analyses via gene expression profiling of hiPSC-CMs infected with CVB3-Luc revealed an activation of viral RNA and protein clearance pathways after interferonβ1 treatment. This study demonstrates that hiPSC-CMs express the coxsackievirus and adenovirus receptor, are susceptible to coxsackievirus infection, and can be used to predict antiviral drug efficacy. Our results suggest that the hiPSC-CM/CVB3-Luc assay is a sensitive platform that can screen novel antiviral therapeutics for their effectiveness in a high-throughput fashion. © 2014 American Heart Association, Inc.

Acute Viral Respiratory Infection Rapidly Induces a CD8+ T Cell Exhaustion-like Phenotype.

PubMed

Erickson, John J; Lu, Pengcheng; Wen, Sherry; Hastings, Andrew K; Gilchuk, Pavlo; Joyce, Sebastian; Shyr, Yu; Williams, John V

2015-11-01

Acute viral infections typically generate functional effector CD8(+) T cells (TCD8) that aid in pathogen clearance. However, during acute viral lower respiratory infection, lung TCD8 are functionally impaired and do not optimally control viral replication. T cells also become unresponsive to Ag during chronic infections and cancer via signaling by inhibitory receptors such as programmed cell death-1 (PD-1). PD-1 also contributes to TCD8 impairment during viral lower respiratory infection, but how it regulates TCD8 impairment and the connection between this state and T cell exhaustion during chronic infections are unknown. In this study, we show that PD-1 operates in a cell-intrinsic manner to impair lung TCD8. In light of this, we compared global gene expression profiles of impaired epitope-specific lung TCD8 to functional spleen TCD8 in the same human metapneumovirus-infected mice. These two populations differentially regulate hundreds of genes, including the upregulation of numerous inhibitory receptors by lung TCD8. We then compared the gene expression of TCD8 during human metapneumovirus infection to those in acute or chronic lymphocytic choriomeningitis virus infection. We find that the immunophenotype of lung TCD8 more closely resembles T cell exhaustion late into chronic infection than do functional effector T cells arising early in acute infection. Finally, we demonstrate that trafficking to the infected lung alone is insufficient for TCD8 impairment or inhibitory receptor upregulation, but that viral Ag-induced TCR signaling is also required. Our results indicate that viral Ag in infected lungs rapidly induces an exhaustion-like state in lung TCD8 characterized by progressive functional impairment and upregulation of numerous inhibitory receptors. Copyright © 2015 by The American Association of Immunologists, Inc.

A Higher Correlation of HCV Core Antigen with CD4+ T Cell Counts Compared with HCV RNA in HCV/HIV-1 Coinfected Patients

PubMed Central

Zhang, Weidong; Xi, Yuanlin; Cao, Guanghua; Zhi, Yuhong; Wang, Shuiwang; Xu, Chunhui; Wei, Lai; Lu, Fengmin; Zhuang, Hui

2011-01-01

Development of HCV infection is typically followed by chronic hepatitis C (CHC) in most patients, while spontaneous HCV viral clearance (SVC) occurs in only a minority of subjects. Compared with the widespread application of HCV RNA testing by quantitative RT-PCR technique, HCV core antigen detection may be an alternative indicator in the diagnosis of hepatitis C virus infections and in monitoring the status of infectious individuals. However, the correlation and differences between these two indicators in HCV infection need more investigation, especially in patients coinfected by HIV-1. In this study, a total of 354 anti-HCV and/or anti-HIV serum positive residents from a village of central China were enrolled. Besides HCV-related hepatopathic variables including clinical status, ALT, AST, anti-HCV Abs, as well as the altered CD4+/CD8+ T cell counts, HCV core antigen and HCV viral load were also measured. The concentration of serum HCV core antigen was highly correlated with level of HCV RNA in CHC patients with or without HIV-1 coinfection. Of note, HCV core antigen concentration was negatively correlated with CD4+ T cell count, while no correlation was found between HCV RNA level and CD4+ T cell count. Our findings suggested that quantitative detection of plasma HCV core antigen may be an alternative indicator of HCV RNA qPCR assay when evaluating the association between HCV replication and host immune status in HCV/HIV-1 coinfected patients. PMID:21858166

Resistance to HSV-1 Infection in the Epithelium Resides with the Novel Innate Sensor, IFI-16

PubMed Central

Conrady, Christopher D.; Zheng, Min; Fitzgerald, Katherine A.; Liu, Chuanju; Carr, Daniel J.J.

2012-01-01

Toll-like receptors (TLRs) are innate sentinels required for clearance of bacterial and fungal infections of the cornea, but their role in viral immunity is currently unknown. We report TLR signaling is expendable in HSV-1 containment as depicted by plaque assays of knockout mice (MyD88−/−, Trif−/− and MyD88−/− Trif−/− DKO) resembling wild type controls. To identify the key sentinel in viral recognition of the cornea, in vivo knockdown of the DNA sensor IFI-16/p204 in corneal epithelium was performed and resulted in a loss of IRF-3 nuclear translocation, interferon-α production, and viral containment. The sensor appears to have a similar function in other HSV clinically-relevant sites such as the vaginal mucosa in which a loss of p204/IFI-16 results in significantly more HSV-2 shedding. Thus, we have identified an IRF-3 dependent, IRF-7 and TLR - independent innate sensor responsible for HSV containment at the site of acute infection. PMID:22236996

The kinetics and location of intra-host HIV evolution to evade cellular immunity are predictable

NASA Astrophysics Data System (ADS)

Barton, John; Goonetilleke, Nilu; Butler, Thomas; Walker, Bruce; McMichael, Andrew; Chakraborty, Arup

Human immunodeficiency virus (HIV) evolves within infected persons to escape targeting and clearance by the host immune system, thereby preventing effective immune control of infection. Knowledge of the timing and pathways of escape that result in loss of control of the virus could aid in the design of effective strategies to overcome the challenge of viral diversification and immune escape. We combined methods from statistical physics and evolutionary dynamics to predict the course of in vivo viral sequence evolution in response to T cell-mediated immune pressure in a cohort of 17 persons with acute HIV infection. Our predictions agree well with both the location of documented escape mutations and the clinically observed time to escape. We also find that that the mutational pathways to escape depend on the viral sequence background due to epistatic interactions. The ability to predict escape pathways, and the duration over which control is maintained by specific immune responses prior to escape, could be exploited for the rational design of immunotherapeutic strategies that may enable long-term control of HIV infection.

Pathogenesis of emerging severe fever with thrombocytopenia syndrome virus in C57/BL6 mouse model

PubMed Central

Jin, Cong; Liang, Mifang; Ning, Junyu; Gu, Wen; Jiang, Hong; Wu, Wei; Zhang, Fushun; Zhang, Quanfu; Zhu, Hua; Chen, Ting; Han, Ying; Zhang, Weilun; Zhang, Shuo; Wang, Qin; Sun, Lina; Liu, Qinzhi; Wang, Tao; Wei, Qiang; Wang, Shiwen; Deng, Ying; Qin, Chuan; Li, Dexin

2012-01-01

The discovery of an emerging viral disease, severe fever with thrombocytopenia syndrome (SFTS), caused by SFTS virus (SFTSV), has prompted the need to understand pathogenesis of SFTSV. We are unique in establishing an infectious model of SFTS in C57/BL6 mice, resulting in hallmark symptoms of thrombocytopenia and leukocytopenia. Viral RNA and histopathological changes were identified in the spleen, liver, and kidney. However, viral replication was only found in the spleen, which suggested the spleen to be the principle target organ of SFTSV. Moreover, the number of macrophages and platelets were largely increased in the spleen, and SFTSV colocalized with platelets in cytoplasm of macrophages in the red pulp of the spleen. In vitro cellular assays further revealed that SFTSV adhered to mouse platelets and facilitated the phagocytosis of platelets by mouse primary macrophages, which in combination with in vivo findings, suggests that SFTSV-induced thrombocytopenia is caused by clearance of circulating virus-bound platelets by splenic macrophages. Thus, this study has elucidated the pathogenic mechanisms of thrombocytopenia in a mouse model resembling human SFTS disease. PMID:22665769

Acute hepatitis C in an HIV-infected patient: a case report and review of literature.

PubMed

Driver, Todd H; Terrault, Norah; Saxena, Varun

2013-05-01

With the decrease in transmission via transfusions and injection drug use, acute symptomatic hepatitis C is infrequently seen in developed countries. We report a case of a human immunodeficiency virus (HIV)-infected adult who presented with abdominal pain. His alanine aminotransferase was greater than sixty times the upper limit of normal without any evidence on examination of fulminant hepatic failure. His workup revealed an elevated hepatitis C viral level with a negative hepatitis C antibody. He was discharged once his liver function tests improved. As an outpatient, he had a recurrent bout of symptoms with an elevation of his alanine aminotransferase and hepatitis C viral levels that promoted anti-hepatitis C virus treatment. This case illustrates the importance of considering acute hepatitis C as a cause of acute hepatitis in HIV-infected men who have sex with men. While patients with acute symptomatic hepatitis C generally have a higher rate of spontaneous viral clearance compared to those with an insidious acute infection, most still progress to chronic hepatitis C infection, and patients with HIV coinfection carry a higher risk of progression to chronic disease.

Virus inhibition of RIP3-dependent necrosis.

PubMed

Upton, Jason W; Kaiser, William J; Mocarski, Edward S

2010-04-22

Viral infection activates cytokine expression and triggers cell death, the modulation of which is important for successful pathogenesis. Necroptosis is a form of programmed necrosis dependent on two related RIP homotypic interaction motif (RHIM)-containing signaling adaptors, receptor-interacting protein kinases (RIP) 1 and 3. We find that murine cytomegalovirus infection induces RIP3-dependent necrosis. Whereas RIP3 kinase activity and RHIM-dependent interactions control virus-associated necrosis, virus-induced death proceeds independently of RIP1 and is therefore distinct from TNFalpha-dependent necroptosis. Viral M45-encoded inhibitor of RIP activation (vIRA) targets RIP3 during infection and disrupts RIP3-RIP1 interactions characteristic of TNFalpha-induced necroptosis, thereby suppressing both death pathways. Importantly, attenuation of vIRA mutant virus in wild-type mice is normalized in RIP3-deficient mice. Thus, vIRA function validates necrosis as central to host defense against viral infections and highlights the benefit of multiple virus-encoded cell-death suppressors that inhibit not only apoptotic, but also necrotic mechanisms of virus clearance. Copyright 2010 Elsevier Inc. All rights reserved.

Assignment of cytomegalovirus infection status in infants awaiting solid organ transplant: Viral detection methods as adjuncts to serology.

PubMed

Burton, Catherine E; Dragan, Tatiana; Mabilangan, Curtis A; O'Brien, Sheila F; Fearon, Margaret; Scalia, Vito; Preiksaitis, Jutta K

2018-05-24

Assignment of CMV infection status in infants awaiting SOT is challenging as passive maternal antibody can lead to false-positive serology. Since 2000, our protocol has recommended sending throat and urine samples for CMV viral detection, culture, or NAAT, for CMV-seropositive infants <18 months awaiting SOT. We reviewed pretransplant CMV serology for 152 infants and, for CMV seropositives, examined relationships between CMV IgG OD values, age, and CMV viral detection to explore time to clearance of maternal CMV IgG and evaluate viral detection in assignment of pretransplant CMV infection status. The proportion of CMV-seropositive infants decreased from 52% in infants 0-6 months of age to 28% in those 12-18 months. Among CMV-seropositive infants, median OD was significantly higher in the 6- to 12- and 12- to 18-month groups compared to the 0- to 6-month group. Distribution of OD by age group suggested that maternal antibody cleared before 12 months. Of 59 eligible CMV-seropositive infants, 49 (83%) had CMV viral detection studies and 18 of 49 (36.7%) had detectable CMV: 9 of 30 (30.0%) infants 0-6 months, 7 of 15 (46.7%) infants 6-12 months, and 2 of 4 (50.0%) infants 12-18 months. CMV viral detection studies are useful to confirm positive CMV infection status in CMV-seropositive infants awaiting SOT. Maternal CMV IgG likely clears before 12 months. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Antiviral macrophage responses in flavivirus encephalitis

PubMed Central

Ashhurst, Thomas Myles; van Vreden, Caryn; Munoz-Erazo, Luis; Niewold, Paula; Watabe, Kanami; Terry, Rachael L.; Deffrasnes, Celine; Getts, Daniel R.; King, Nicholas Jonathan Cole

2013-01-01

Mosquito-borne flaviviruses are a major current and emerging threat, affecting millions of people worldwide. Global climate change, combined with increasing proximity of humans to animals and mosquito vectors by expansion into natural habitats, coupled with the increase in international travel, have resulted in significant spread and concomitant increase in the incidence of infection and severe disease. Although neuroinvasive disease has been well described for some viral infections such as Japanese Encephalitis virus (JEV) and West Nile virus (WNV), others such as dengue virus (DENV) have recently displayed an emerging pattern of neuroinvasive disease, distinct from the previously observed, systemically-induced encephalomyelopathy. In this setting, the immune response is a crucial component of host defence, in preventing viral dissemination and invasion of the central nervous system (CNS). However, subversion of the anti-viral activities of macrophages by flaviviruses can facilitate viral replication and spread, enhancing the intensity of immune responses, leading to severe immune-mediated disease which may be further exacerbated during the subsequent infection with some flaviviruses. Furthermore, in the CNS myeloid cells may be responsible for inducing specific inflammatory changes, which can lead to significant pathological damage during encephalitis. The interaction of virus and cells of the myeloid lineage is complex, and this interaction is likely responsible at least in part, for crucial differences between viral clearance and pathology. Recent studies on the role of myeloid cells in innate immunity and viral control, and the mechanisms of evasion and subversion used by flaviviruses are rapidly advancing our understanding of the immunopathological mechanisms involved in flavivirus encephalitis and will lead to the development of therapeutic strategies previously not considered. PMID:24434318

Design optimization of dual-axis driving mechanism for satellite antenna with two planar revolute clearance joints

NASA Astrophysics Data System (ADS)

Bai, Zheng Feng; Zhao, Ji Jun; Chen, Jun; Zhao, Yang

2018-03-01

In the dynamic analysis of satellite antenna dual-axis driving mechanism, it is usually assumed that the joints are ideal or perfect without clearances. However, in reality, clearances in joints are unavoidable due to assemblage, manufacturing errors and wear. When clearance is introduced to the mechanism, it will lead to poor dynamic performances and undesirable vibrations due to impact forces in clearance joint. In this paper, a design optimization method is presented to reduce the undesirable vibrations of satellite antenna considering clearance joints in dual-axis driving mechanism. The contact force model in clearance joint is established using a nonlinear spring-damper model and the friction effect is considered using a modified Coulomb friction model. Firstly, the effects of clearances on dynamic responses of satellite antenna are investigated. Then the optimization method for dynamic design of the dual-axis driving mechanism with clearance is presented. The objective of the optimization is to minimize the maximum absolute vibration peak of antenna acceleration by reducing the impact forces in clearance joint. The main consideration here is to optimize the contact parameters of the joint elements. The contact stiffness coefficient, damping coefficient and the dynamic friction coefficient for clearance joint elements are taken as the optimization variables. A Generalized Reduced Gradient (GRG) algorithm is used to solve this highly nonlinear optimization problem for dual-axis driving mechanism with clearance joints. The results show that the acceleration peaks of satellite antenna and contact forces in clearance joints are reduced obviously after design optimization, which contributes to a better performance of the satellite antenna. Also, the application and limitation of the proposed optimization method are discussed.

Roles of neutrophils in the regulation of the extent of human inflammation through delivery of IL-1 and clearance of chemokines

PubMed Central

Basran, Alexander; Jabeen, Maisha; Bingle, Lynne; Stokes, Clare A.; Dockrell, David H.; Whyte, Moira K. B.; Walmsley, Sarah R.; Higgins, Kathryn R.; Vogel, Stefanie N.; Wilson, Heather L.; Prince, Lynne R.; Prestwich, Elizabeth C.; Sabroe, Ruth A.; Parker, Lisa C.; Sabroe, Ian

2013-01-01

This study examined the establishment of neutrophilic inflammation in humans. We tested the hypotheses that neutrophil recruitment was associated with local CXCL8 production and that neutrophils themselves might contribute to the regulation of the size of the inflammatory response. Humans were challenged i.d. with endotoxin. Biopsies of these sites were examined for cytokine production and leukocyte recruitment by qPCR and IHC. Additional in vitro models of inflammation examined the ability of neutrophils to produce and sequester cytokines relevant to neutrophilic inflammation. i.d. challenge with 15 ng of a TLR4-selective endotoxin caused a local inflammatory response, in which 1% of the total biopsy area stained positive for neutrophils at 6 h, correlating with 100-fold up-regulation in local CXCL8 mRNA generation. Neutrophils themselves were the major source of the early cytokine IL-1β. In vitro, neutrophils mediated CXCL8 but not IL-1β clearance (>90% clearance of ≤2 nM CXCL8 over 24 h). CXCL8 clearance was at least partially receptor-dependent and modified by inflammatory context, preserved in models of viral infection but reduced in models of bacterial infection. In conclusion, in a human inflammatory model, neutrophils are rapidly recruited and may regulate the size and outcome of the inflammatory response through the uptake and release of cytokines and chemokines in patterns dependent on the underlying inflammatory stimulus. PMID:22904343

Prechamber Compression-Ignition Engine Performance

NASA Technical Reports Server (NTRS)

Moore, Charles S; Collins, John H , Jr

1938-01-01

Single-cylinder compression-ignition engine tests were made to investigate the performance characteristics of prechamber type of cylinder head. Certain fundamental variables influencing engine performance -- clearance distribution, size, shape, and direction of the passage connecting the cylinder and prechamber, shape of prechamber, cylinder clearance, compression ratio, and boosting -- were independently tested. Results of motoring and of power tests, including several typical indicator cards, are presented.

Transmitted/Founder Viruses Rapidly Escape from CD8+ T Cell Responses in Acute Hepatitis C Virus Infection.

PubMed

Bull, Rowena A; Leung, Preston; Gaudieri, Silvana; Deshpande, Pooja; Cameron, Barbara; Walker, Melanie; Chopra, Abha; Lloyd, Andrew R; Luciani, Fabio

2015-05-01

The interaction between hepatitis C virus (HCV) and cellular immune responses during very early infection is critical for disease outcome. To date, the impact of antigen-specific cellular immune responses on the evolution of the viral population establishing infection and on potential escape has not been studied. Understanding these early host-virus dynamics is important for the development of a preventative vaccine. Three subjects who were followed longitudinally from the detection of viremia preseroconversion until disease outcome were analyzed. The evolution of transmitted/founder (T/F) viruses was undertaken using deep sequencing. CD8(+) T cell responses were measured via enzyme-linked immunosorbent spot (ELISpot) assay using HLA class I-restricted T/F epitopes. T/F viruses were rapidly extinguished in all subjects associated with either viral clearance (n = 1) or replacement with viral variants leading to establishment of chronic infection (n = 2). CD8(+) T cell responses against 11 T/F epitopes were detectable by 33 to 44 days postinfection, and 5 of these epitopes had not previously been reported. These responses declined rapidly in those who became chronically infected and were maintained in the subject who cleared infection. Higher-magnitude CD8(+) T cell responses were associated with rapid development of immune escape variants at a rate of up to 0.1 per day. Rapid escape from CD8(+) T cell responses has been quantified for the first time in the early phase of primary HCV infection. These rapid escape dynamics were associated with higher-magnitude CD8(+) T cell responses. These findings raise questions regarding optimal selection of immunogens for HCV vaccine development and suggest that detailed analysis of individual epitopes may be required. A major limitation in our detailed understanding of the role of immune response in HCV clearance has been the lack of data on very early primary infection when the transmitted viral variants successfully establish the acute infection. This study was made possible through the availability of specimens from a unique cohort of asymptomatic primary infection cases in whom the first available viremic samples were collected approximately 3 weeks postinfection and at regular intervals thereafter. The study included detailed examination of both the evolution of the viral population and the host cellular immune responses against the T/F viruses. The findings here provide the first evidence of host cellular responses targeting T/F variants and imposing a strong selective force toward viral escape. The results of this study provide useful insight on how virus escapes the host response and consequently on future analysis of vaccine-induced immunity. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Comparative Performance of Reagents and Platforms for Quantitation of Cytomegalovirus DNA by Digital PCR

PubMed Central

Gu, Z.; Sam, S. S.; Sun, Y.; Tang, L.; Pounds, S.; Caliendo, A. M.

2016-01-01

A potential benefit of digital PCR is a reduction in result variability across assays and platforms. Three sets of PCR reagents were tested on two digital PCR systems (Bio-Rad and RainDance), using three different sets of PCR reagents for quantitation of cytomegalovirus (CMV). Both commercial quantitative viral standards and 16 patient samples (n = 16) were tested. Quantitative accuracy (compared to nominal values) and variability were determined based on viral standard testing results. Quantitative correlation and variability were assessed with pairwise comparisons across all reagent-platform combinations for clinical plasma sample results. The three reagent sets, when used to assay quantitative standards on the Bio-Rad system, all showed a high degree of accuracy, low variability, and close agreement with one another. When used on the RainDance system, one of the three reagent sets appeared to have a much better correlation to nominal values than did the other two. Quantitative results for patient samples showed good correlation in most pairwise comparisons, with some showing poorer correlations when testing samples with low viral loads. Digital PCR is a robust method for measuring CMV viral load. Some degree of result variation may be seen, depending on platform and reagents used; this variation appears to be greater in samples with low viral load values. PMID:27535685

The IL-1R/TLR signaling pathway is essential for efficient CD8+ T-cell responses against hepatitis B virus in the hydrodynamic injection mouse model.

PubMed

Ma, Zhiyong; Liu, Jia; Wu, Weimin; Zhang, Ejuan; Zhang, Xiaoyong; Li, Qian; Zelinskyy, Gennadiy; Buer, Jan; Dittmer, Ulf; Kirschning, Carsten J; Lu, Mengji

2017-12-01

The outcome of hepatitis B viral (HBV) infection is determined by the complex interactions between replicating HBV and the immune system. While the role of the adaptive immune system in the resolution of HBV infection has been studied extensively, the contribution of innate immune mechanisms remains to be defined. Here we examined the role of the interleukin-1 receptor/Toll-like receptor (IL-1R/TLR) signaling pathway in adaptive immune responses and viral clearance by exploring the HBV mouse model. Hydrodynamic injection with a replication-competent HBV genome was performed in wild-type mice (WT) and a panel of mouse strains lacking specific innate immunity component expression. We found higher levels of HBV protein production and replication in Tlr2 -/- , Tlr23479 -/- , 3d/Tlr24 -/- , Myd88/Trif -/- and Irak4 -/- mice, which was associated with reduced HBV-specific CD8 + T-cell responses in these mice. Importantly, HBV clearance was delayed for more than 2 weeks in 3d/Tlr24 -/- , Myd88/Trif -/- and Irak4 -/- mice compared to WT mice. HBV-specific CD8 + T-cell responses were functionally impaired for producing the cytokines IFN-γ, TNF-α and IL-2 in TLR signaling-deficient mice compared to WT mice. In conclusion, the IL-1R/TLR signaling pathway might contribute to controlling HBV infection by augmenting HBV-specific CD8 + T-cell responses.

Population pharmacokinetic approach to evaluate the effect of CYP2D6, CYP3A, ABCB1, POR and NR1I2 genotypes on donepezil clearance

PubMed Central

Noetzli, Muriel; Guidi, Monia; Ebbing, Karsten; Eyer, Stephan; Wilhelm, Laurence; Michon, Agnès; Thomazic, Valérie; Stancu, Ioana; Alnawaqil, Abdel-Messieh; Bula, Christophe; Zumbach, Serge; Gaillard, Michel; Giannakopoulos, Panteleimon; von Gunten, Armin; Csajka, Chantal; Eap, Chin B

2014-01-01

Aims A large interindividual variability in plasma concentrations has been reported in patients treated with donepezil, the most frequently prescribed antidementia drug. We aimed to evaluate clinical and genetic factors influencing donepezil disposition in a patient population recruited from a naturalistic setting. Methods A population pharmacokinetic study was performed including data from 129 older patients treated with donepezil. The patients were genotyped for common polymorphisms in the metabolic enzymes CYP2D6 and CYP3A, in the electron transferring protein POR and the nuclear factor NR1I2 involved in CYP activity and expression, and in the drug transporter ABCB1. Results The average donepezil clearance was 7.3 l h−1 with a 30% interindividual variability. Gender markedly influenced donepezil clearance (P < 0.01). Functional alleles of CYP2D6 were identified as unique significant genetic covariate for donepezil clearance (P < 0.01), with poor metabolizers and ultrarapid metabolizers demonstrating, respectively, a 32% slower and a 67% faster donepezil elimination compared with extensive metabolizers. Conclusion The pharmacokinetic parameters of donepezil were well described by the developed population model. Functional alleles of CYP2D6 significantly contributed to the variability in donepezil disposition in the patient population and should be further investigated in the context of individual dose optimization to improve clinical outcome and tolerability of the treatment. PMID:24433464

Population pharmacokinetic approach to evaluate the effect of CYP2D6, CYP3A, ABCB1, POR and NR1I2 genotypes on donepezil clearance.

PubMed

Noetzli, Muriel; Guidi, Monia; Ebbing, Karsten; Eyer, Stephan; Wilhelm, Laurence; Michon, Agnès; Thomazic, Valérie; Stancu, Ioana; Alnawaqil, Abdel-Messieh; Bula, Christophe; Zumbach, Serge; Gaillard, Michel; Giannakopoulos, Panteleimon; von Gunten, Armin; Csajka, Chantal; Eap, Chin B

2014-07-01

A large interindividual variability in plasma concentrations has been reported in patients treated with donepezil, the most frequently prescribed antidementia drug. We aimed to evaluate clinical and genetic factors influencing donepezil disposition in a patient population recruited from a naturalistic setting. A population pharmacokinetic study was performed including data from 129 older patients treated with donepezil. The patients were genotyped for common polymorphisms in the metabolic enzymes CYP2D6 and CYP3A, in the electron transferring protein POR and the nuclear factor NR1I2 involved in CYP activity and expression, and in the drug transporter ABCB1. The average donepezil clearance was 7.3 l h(-1) with a 30% interindividual variability. Gender markedly influenced donepezil clearance (P < 0.01). Functional alleles of CYP2D6 were identified as unique significant genetic covariate for donepezil clearance (P < 0.01), with poor metabolizers and ultrarapid metabolizers demonstrating, respectively, a 32% slower and a 67% faster donepezil elimination compared with extensive metabolizers. The pharmacokinetic parameters of donepezil were well described by the developed population model. Functional alleles of CYP2D6 significantly contributed to the variability in donepezil disposition in the patient population and should be further investigated in the context of individual dose optimization to improve clinical outcome and tolerability of the treatment. © 2014 The British Pharmacological Society.

Functional genomics reveals an essential and specific role for Stat1 in protection of the central nervous system following herpes simplex virus corneal infection.

PubMed

Pasieka, Tracy Jo; Cilloniz, Cristian; Carter, Victoria S; Rosato, Pamela; Katze, Michael G; Leib, David A

2011-12-01

Innate immune deficiencies result in a spectrum of severe clinical outcomes following infection. In particular, there is a strong association between loss of the signal transducer and activator of transcription (Stat) pathway, breach of the blood-brain barrier (BBB), and virus-induced neuropathology. The gene signatures that characterize resistance, disease, and mortality in the virus-infected nervous system have not been defined. Herpes simplex virus type 1 (HSV-1) is commonly associated with encephalitis in humans, and humans and mice lacking Stat1 display increased susceptibility to HSV central nervous system (CNS) infections. In this study, two HSV-1 strains were used, KOS (wild type [WT]), and Δvhs, an avirulent recombinant lacking the virion host shutoff (vhs) function. In addition, two mouse strains were used: strain 129 (control) and a Stat1-deficient (Stat1(-/-)) strain. Using combinations of these virus and mouse strains, we established a model of infection resulting in three different outcomes: viral clearance without neurological disease (Δvhs infection of control mice), neurological disease followed by viral clearance (Δvhs infection of Stat1(-/-) mice and WT infection of control mice), or neurological disease followed by death (WT infection of Stat1(-/-) mice). Through the use of functional genomics on the infected brain stems, we determined gene signatures that were representative of the three infection outcomes. We demonstrated a pathological signature in the brain stem of Stat1-deficient mice characterized by upregulation of transcripts encoding chemokine receptors, inflammatory markers, neutrophil chemoattractants, leukocyte adhesion proteins, and matrix metalloproteases. Additionally, there was a greater than 100-fold increase in the inflammatory markers interleukin 1β (IL-1β) and IL-6. Consistent with this gene signature, we demonstrated profound CNS inflammation with a concomitant lethal breach of the BBB. Taken together, our results indicated an essential role for normal Stat1-dependent signaling in mediating a nonpathological immune response to viral CNS infection.

Reducing inherent biases introduced during DNA viral metagenome analyses of municipal wastewater

EPA Science Inventory

Metagenomics is a powerful tool for characterizing viral composition within environmental samples, but sample and molecular processing steps can bias the estimation of viral community structure. The objective of this study is to understand the inherent variability introduced when...

In–Depth Characterization of Viral Isolates from Plasma and Cells Compared with Plasma Circulating Quasispecies in Early HIV-1 Infection

PubMed Central

Erkizia, Itziar; Pino, Maria; Pou, Christian; Paredes, Roger; Clotet, Bonaventura; Martinez-Picado, Javier; Prado, Julia G.

2012-01-01

Background The use of in vitro models to unravel the phenotypic characteristics of circulating viral variants is key to understanding HIV-1 pathogenesis but limited by the availability of primary viral isolates from biological samples. However, overall in vivo genetic variability of HIV-1 within a subject may not be reflected in the viable viral population obtained after isolation. Although several studies have tried to determine whether viral populations expanded in vitro are representative of in vivo findings, the answer remains unclear due to the reduced number of clonal sequences analyzed or samples compared. In order to overcome previous experimental limitations, here we applied Deep Pyrosequencing (DPS) technology in combination with phenotypic experiments to analyze and compare with unprecedented detail the composition of viral isolates and in vivo quasispecies. Methodology/Principal Findings We amplified by DPS HIV-1 genomic regions covering gag, protease, integrase and env-V3 to characterize paired isolates from plasma and peripheral blood mononuclear cells and compare them with total plasma viral RNA in four recently HIV-1 infected subjects. Our study demonstrated the presence of unique haplotypes scattered between sample types with conservation of major variants. In addition, no differences in intra- and inter-population encoded protein variability were found between the different types of isolates or when these were compared to plasma viral RNA within subjects. Additionally, in vitro experiments demonstrated phenotypic similarities in terms of replicative capacity and co-receptor usage between viral isolates and plasma viral RNA. Conclusion This study is the first in-depth comparison and characterization of viral isolates from different sources and plasma circulating quasispecies using DPS in recently HIV-1 infected subjects. Our data supports the use of primary isolates regardless of their plasma or cellular origin to define genetic variability and biological traits of circulating HIV-1 quasispecies. PMID:22393441

Vaccine-preventable infections in Systemic Lupus Erythematosus

PubMed Central

Murdaca, Giuseppe; Orsi, Andrea; Spanò, Francesca; Faccio, Valeria; Puppo, Francesco; Durando, Paolo; Icardi, Giancarlo; Ansaldi, Filippo

2016-01-01

Systemic Lupus Erythematosus (SLE) is characterized by abnormal autoantibody production and clearance. Infections are among the most important causes of morbidity and mortality in SLE patients; they have an increased frequency of severe bacterial and viral infections possibly due to inherited genetic and immunologic defects and to immunosuppressive therapies. In addition, infectious agents can switch on lupus disease expression and activity. Among the strategies to reduce the risk of infection, vaccination can be considered the most reliable option. Most vaccines are effective and safe in SLE patients, although in certain cases immunogenicity may be sub-optimal and vaccination can trigger a flare. Although these issues are currently unresolved, the risk benefit balance is in favor for vaccination to reduce the risk of infection in SLE patients. In the present review we discuss the preventive strategies currently recommended to reduce bacterial and viral infections in SLE. PMID:26750996

Estrogen mediates innate and adaptive immune alterations to influenza infection in pregnant mice.

PubMed

Pazos, Michael A; Kraus, Thomas A; Muñoz-Fontela, César; Moran, Thomas M

2012-01-01

Pregnancy is a leading risk factor for severe complications during an influenza virus infection. Women infected during their second and third trimesters are at increased risk for severe cardiopulmonary complications, premature delivery, and death. Here, we establish a murine model of aerosolized influenza infection during pregnancy. We find significantly altered innate antiviral responses in pregnant mice, including decreased levels of IFN-β, IL-1α, and IFN-γ at early time points of infection. We also find reduced cytotoxic T cell activity and delayed viral clearance. We further demonstrate that pregnancy levels of the estrogen 17-β-estradiol are able to induce key anti-inflammatory phenotypes in immune responses to the virus independently of other hormones or pregnancy-related stressors. We conclude that elevated estrogen levels result in an attenuated anti-viral immune response, and that pregnancy-associated morbidities occur in the context of this anti-inflammatory phenotype.

Primary intestinal lymphangiectasia with generalized warts.

PubMed

Lee, Soon Jae; Song, Hyun Joo; Boo, Sun-Jin; Na, Soo-Young; Kim, Heung Up; Hyun, Chang Lim

2015-07-21

Primary intestinal lymphangiectasia (PIL) is a rare protein-losing enteropathy with lymphatic leakage into the small intestine. Dilated lymphatics in the small intestinal wall and mesentery are observed in this disease. Laboratory tests of PIL patients revealed hypoalbuminemia, lymphocytopenia, hypogammaglobulinemia and increased stool α-1 antitrypsin clearance. Cell-mediated immunodeficiency is also present in PIL patients because of loss of lymphocytes. As a result, the patients are vulnerable to chronic viral infection and lymphoma. However, cases of PIL with chronic viral infection, such as human papilloma virus-induced warts, are rarely reported. We report a rare case of PIL with generalized warts in a 36-year-old male patient. PIL was diagnosed by capsule endoscopy and colonoscopic biopsy with histological tissue confirmation. Generalized warts were observed on the head, chest, abdomen, back, anus, and upper and lower extremities, including the hands and feet of the patient.

Primary intestinal lymphangiectasia with generalized warts

PubMed Central

Lee, Soon Jae; Song, Hyun Joo; Boo, Sun-Jin; Na, Soo-Young; Kim, Heung Up; Hyun, Chang Lim

2015-01-01

Primary intestinal lymphangiectasia (PIL) is a rare protein-losing enteropathy with lymphatic leakage into the small intestine. Dilated lymphatics in the small intestinal wall and mesentery are observed in this disease. Laboratory tests of PIL patients revealed hypoalbuminemia, lymphocytopenia, hypogammaglobulinemia and increased stool α-1 antitrypsin clearance. Cell-mediated immunodeficiency is also present in PIL patients because of loss of lymphocytes. As a result, the patients are vulnerable to chronic viral infection and lymphoma. However, cases of PIL with chronic viral infection, such as human papilloma virus-induced warts, are rarely reported. We report a rare case of PIL with generalized warts in a 36-year-old male patient. PIL was diagnosed by capsule endoscopy and colonoscopic biopsy with histological tissue confirmation. Generalized warts were observed on the head, chest, abdomen, back, anus, and upper and lower extremities, including the hands and feet of the patient. PMID:26217101

Unconventional repertoire profile is imprinted during acute chikungunya infection for natural killer cells polarization toward cytotoxicity.

PubMed

Petitdemange, Caroline; Becquart, Pierre; Wauquier, Nadia; Béziat, Vivien; Debré, Patrice; Leroy, Eric M; Vieillard, Vincent

2011-09-01

Chikungunya virus (CHIKV) is a worldwide emerging pathogen. In humans it causes a syndrome characterized by high fever, polyarthritis, and in some cases lethal encephalitis. Growing evidence indicates that the innate immune response plays a role in controlling CHIKV infection. We show here that CHIKV induces major but transient modifications in NK-cell phenotype and function soon after the onset of acute infection. We report a transient clonal expansion of NK cells that coexpress CD94/NKG2C and inhibitory receptors for HLA-C1 alleles and are correlated with the viral load. Functional tests reveal cytolytic capacity driven by NK cells in the absence of exogenous signals and severely impaired IFN-γ production. Collectively these data provide insight into the role of this unique subset of NK cells in controlling CHIKV infection by subset-specific expansion in response to acute infection, followed by a contraction phase after viral clearance.

Viral genetic variation accounts for a third of variability in HIV-1 set-point viral load in Europe.

PubMed

Blanquart, François; Wymant, Chris; Cornelissen, Marion; Gall, Astrid; Bakker, Margreet; Bezemer, Daniela; Hall, Matthew; Hillebregt, Mariska; Ong, Swee Hoe; Albert, Jan; Bannert, Norbert; Fellay, Jacques; Fransen, Katrien; Gourlay, Annabelle J; Grabowski, M Kate; Gunsenheimer-Bartmeyer, Barbara; Günthard, Huldrych F; Kivelä, Pia; Kouyos, Roger; Laeyendecker, Oliver; Liitsola, Kirsi; Meyer, Laurence; Porter, Kholoud; Ristola, Matti; van Sighem, Ard; Vanham, Guido; Berkhout, Ben; Kellam, Paul; Reiss, Peter; Fraser, Christophe

2017-06-01

HIV-1 set-point viral load-the approximately stable value of viraemia in the first years of chronic infection-is a strong predictor of clinical outcome and is highly variable across infected individuals. To better understand HIV-1 pathogenesis and the evolution of the viral population, we must quantify the heritability of set-point viral load, which is the fraction of variation in this phenotype attributable to viral genetic variation. However, current estimates of heritability vary widely, from 6% to 59%. Here we used a dataset of 2,028 seroconverters infected between 1985 and 2013 from 5 European countries (Belgium, Switzerland, France, the Netherlands and the United Kingdom) and estimated the heritability of set-point viral load at 31% (CI 15%-43%). Specifically, heritability was measured using models of character evolution describing how viral load evolves on the phylogeny of whole-genome viral sequences. In contrast to previous studies, (i) we measured viral loads using standardized assays on a sample collected in a strict time window of 6 to 24 months after infection, from which the viral genome was also sequenced; (ii) we compared 2 models of character evolution, the classical "Brownian motion" model and another model ("Ornstein-Uhlenbeck") that includes stabilising selection on viral load; (iii) we controlled for covariates, including age and sex, which may inflate estimates of heritability; and (iv) we developed a goodness of fit test based on the correlation of viral loads in cherries of the phylogenetic tree, showing that both models of character evolution fit the data well. An overall heritability of 31% (CI 15%-43%) is consistent with other studies based on regression of viral load in donor-recipient pairs. Thus, about a third of variation in HIV-1 virulence is attributable to viral genetic variation.

Population pharmacokinetic study of memantine: effects of clinical and genetic factors.

PubMed

Noetzli, Muriel; Guidi, Monia; Ebbing, Karsten; Eyer, Stephan; Wilhelm, Laurence; Michon, Agnès; Thomazic, Valérie; Alnawaqil, Abdel-Messieh; Maurer, Sophie; Zumbach, Serge; Giannakopoulos, Panteleimon; von Gunten, Armin; Csajka, Chantal; Eap, Chin B

2013-03-01

Memantine, a frequently prescribed anti-dementia drug, is mainly eliminated unchanged by the kidneys, partly via tubular secretion. Considerable inter-individual variability in plasma concentrations has been reported. We aimed to investigate clinical and genetic factors influencing memantine disposition. A population pharmacokinetic study was performed including data from 108 patients recruited in a naturalistic setting. Patients were genotyped for common polymorphisms in renal cation transporters (SLC22A1/2/5, SLC47A1, ABCB1) and nuclear receptors (NR1I2, NR1I3, RXR, PPAR) involved in transporter expression. The average clearance was 5.2 L/h with a 27 % inter-individual variability (percentage coefficient of variation). Glomerular filtration rate (p = 0.007) and sex (p = 0.001) markedly influenced memantine clearance. NR1I2 rs1523130 was identified as the unique significant genetic covariate for memantine clearance (p = 0.006), with carriers of the NR1I2 rs1523130 CT/TT genotypes presenting a 16 % slower memantine elimination than carriers of the CC genotype. The better understanding of inter-individual variability of memantine disposition might be beneficial in the context of individual dose optimization.

Early lactate clearance for predicting active bleeding in critically ill patients with acute upper gastrointestinal bleeding: a retrospective study.

PubMed

Wada, Tomoki; Hagiwara, Akiyoshi; Uemura, Tatsuki; Yahagi, Naoki; Kimura, Akio

2016-08-01

Not all patients with upper gastrointestinal bleeding (UGIB) require emergency endoscopy. Lactate clearance has been suggested as a parameter for predicting patient outcomes in various critical care settings. This study investigates whether lactate clearance can predict active bleeding in critically ill patients with UGIB. This single-center, retrospective, observational study included critically ill patients with UGIB who met all of the following criteria: admission to the emergency department (ED) from April 2011 to August 2014; had blood samples for lactate evaluation at least twice during the ED stay; and had emergency endoscopy within 6 h of ED presentation. The main outcome was active bleeding detected with emergency endoscopy. Classification and regression tree (CART) analyses were performed using variables associated with active bleeding to derive a prediction rule for active bleeding in critically ill UGIB patients. A total of 154 patients with UGIB were analyzed, and 31.2 % (48/154) had active bleeding. In the univariate analysis, lactate clearance was significantly lower in patients with active bleeding than in those without active bleeding (13 vs. 29 %, P < 0.001). Using the CART analysis, a prediction rule for active bleeding is derived, and includes three variables: lactate clearance; platelet count; and systolic blood pressure at ED presentation. The rule has 97.9 % (95 % CI 90.2-99.6 %) sensitivity with 32.1 % (28.6-32.9 %) specificity. Lactate clearance may be associated with active bleeding in critically ill patients with UGIB, and may be clinically useful as a component of a prediction rule for active bleeding.

Covariates of intravenous paracetamol pharmacokinetics in adults

PubMed Central

2014-01-01

Background Pharmacokinetic estimates for intravenous paracetamol in individual adult cohorts are different to a certain extent, and understanding the covariates of these differences may guide dose individualization. In order to assess covariate effects of intravenous paracetamol disposition in adults, pharmacokinetic data on discrete studies were pooled. Methods This pooled analysis was based on 7 studies, resulting in 2755 time-concentration observations in 189 adults (mean age 46 SD 23 years; weight 73 SD 13 kg) given intravenous paracetamol. The effects of size, age, pregnancy and other clinical settings (intensive care, high dependency, orthopaedic or abdominal surgery) on clearance and volume of distribution were explored using non-linear mixed effects models. Results Paracetamol disposition was best described using normal fat mass (NFM) with allometric scaling as a size descriptor. A three-compartment linear disposition model revealed that the population parameter estimates (between subject variability,%) were central volume (V1) 24.6 (55.5%) L/70 kg with peripheral volumes of distribution V2 23.1 (49.6%) L/70 kg and V3 30.6 (78.9%) L/70 kg. Clearance (CL) was 16.7 (24.6%) L/h/70 kg and inter-compartment clearances were Q2 67.3 (25.7%) L/h/70 kg and Q3 2.04 (71.3%) L/h/70 kg. Clearance and V2 decreased only slightly with age. Sex differences in clearance were minor and of no significance. Clearance, relative to median values, was increased during pregnancy (FPREG = 1.14) and decreased during abdominal surgery (FABDCL = 0.715). Patients undergoing orthopaedic surgery had a reduced V2 (FORTHOV = 0.649), while those in intensive care had increased V2 (FICV = 1.51). Conclusions Size and age are important covariates for paracetamol pharmacokinetics explaining approximately 40% of clearance and V2 variability. Dose individualization in adult subpopulations would achieve little benefit in the scenarios explored. PMID:25342929

Analysis of host genetic diversity and viral entry as sources of between-host variation in viral load

USGS Publications Warehouse

Wargo, Andrew R.; Kell, Alison M.; Scott, Robert J.; Thorgaard, Gary H.; Kurath, Gael

2012-01-01

Little is known about the factors that drive the high levels of between-host variation in pathogen burden that are frequently observed in viral infections. Here, two factors thought to impact viral load variability, host genetic diversity and stochastic processes linked with viral entry into the host, were examined. This work was conducted with the aquatic vertebrate virus, Infectious hematopoietic necrosis virus (IHNV), in its natural host, rainbow trout. It was found that in controlled in vivo infections of IHNV, a suggestive trend of reduced between-fish viral load variation was observed in a clonal population of isogenic trout compared to a genetically diverse population of out-bred trout. However, this trend was not statistically significant for any of the four viral genotypes examined, and high levels of fish-to-fish variation persisted even in the isogenic trout population. A decrease in fish-to-fish viral load variation was also observed in virus injection challenges that bypassed the host entry step, compared to fish exposed to the virus through the natural water-borne immersion route of infection. This trend was significant for three of the four virus genotypes examined and suggests host entry may play a role in viral load variability. However, high levels of viral load variation also remained in the injection challenges. Together, these results indicate that although host genetic diversity and viral entry may play some role in between-fish viral load variation, they are not major factors. Other biological and non-biological parameters that may influence viral load variation are discussed.

The population pharmacokinetics of R- and S-warfarin: effect of genetic and clinical factors.

PubMed

Lane, Steven; Al-Zubiedi, Sameh; Hatch, Ellen; Matthews, Ivan; Jorgensen, Andrea L; Deloukas, Panos; Daly, Ann K; Park, B Kevin; Aarons, Leon; Ogungbenro, Kayode; Kamali, Farhad; Hughes, Dyfrig; Pirmohamed, Munir

2012-01-01

Warfarin is a drug with a narrow therapeutic index and large interindividual variability in daily dosing requirements. Patients commencing warfarin treatment are at risk of bleeding due to excessive anticoagulation caused by overdosing. The interindividual variability in dose requirements is influenced by a number of factors, including polymorphisms in genes mediating warfarin pharmacology, co-medication, age, sex, body size and diet. To develop population pharmacokinetic models of both R- and S-warfarin using clinical and genetic factors and to identify the covariates which influence the interindividual variability in the pharmacokinetic parameters of clearance and volume of distribution in patients on long-term warfarin therapy. Patients commencing warfarin therapy were followed up for 26 weeks. Plasma warfarin enantiomer concentrations were determined in 306 patients for S-warfarin and in 309 patients for R-warfarin at 1, 8 and 26 weeks. Patients were also genotyped for CYP2C9 variants (CYP2C9*1,*2 and *3), two single-nucleotide polymorphisms (SNPs) in CYP1A2, one SNP in CYP3A4 and six SNPs in CYP2C19. A base pharmacokinetic model was developed using NONMEM software to determine the warfarin clearance and volume of distribution. The model was extended to include covariates that influenced the between-subject variability. Bodyweight, age, sex and CYP2C9 genotype significantly influenced S-warfarin clearance. The S-warfarin clearance was estimated to be 0.144 l h⁻¹ (95% confidence interval 0.131, 0.157) in a 70 kg woman aged 69.8 years with the wild-type CYP2C9 genotype, and the volume of distribution was 16.6 l (95% confidence interval 13.5, 19.7). Bodyweight and age, along with the SNPs rs3814637 (in CYP2C19) and rs2242480 (in CYP3A4), significantly influenced R-warfarin clearance. The R-warfarin clearance was estimated to be 0.125 l h⁻¹ (95% confidence interval 0.115, 0.135) in a 70 kg individual aged 69.8 years with the wild-type CYP2C19 and CYP3A4 genotypes, and the volume of distribution was 10.9 l (95% confidence interval 8.63, 13.2). Our analysis, based on exposure rather than dose, provides quantitative estimates of the clinical and genetic factors impacting on the clearance of both the S- and R-enantiomers of warfarin, which can be used in developing improved dosing algorithms. © 2011 The Authors. British Journal of Clinical Pharmacology © 2011 The British Pharmacological Society.

Viral load of patients with hantavirus pulmonary syndrome in Argentina.

PubMed

Bellomo, Carla María; Pires-Marczeski, Fanny Clara; Padula, Paula Julieta

2015-11-01

Hantavirus causes severe illness including pneumonia, which leads to hospitalization and often death. At present, there is no specific treatment available. The hantavirus pathogenesis is not well understood, but most likely both virus-mediated and host-mediated mechanisms, are involved. The aim of this study was to correlate viral load in samples of hantavirus pulmonary syndrome cases and hantavirus infected individuals, with clinical epidemiological parameters and disease outcome. The variables that could potentially be related with viral load were analyzed. The retrospective study included 73 cases or household contacts, with different clinical evolution. Viral load was measured by reverse-transcription and real time polymerase chain reaction. There was no statistically significant association between blood viral RNA levels and severity of disease. However, viral load was inversely correlated with IgG response in a statistically significant manner. The level of viral RNA was significantly higher in patients infected with Andes virus South lineage, and was markedly low in persons infected with Laguna Negra virus. These results suggest that the infecting viral genotype is associated with disease severity, and that high viral load is associated with a low specific IgG response. Sex, age and disease severity were not related with viral load. Further investigations increasing strikingly the number of cases and also limiting the variables to be studied are necessary. © 2015 Wiley Periodicals, Inc.

Theoretic criteria for antibody penetration into solid tumors and micrometastases.

PubMed

Thurber, Greg M; Zajic, Stefan C; Wittrup, K Dane

2007-06-01

Targeting tumors with antibody-based therapeutics is a complex task presenting multiple kinetic barriers. Antibody internalization and clearance inhibit uptake both in solid tumors, limited by tumor vascular permeability, and in micrometastases, limited by diffusion. A modeling exercise is used to introduce 2 simple criteria that must be less than unity for saturation of both tumors and micrometastases. The clearance modulus and the Thiele modulus are ratios of the plasma clearance rate and antibody catabolism, respectively, to the tumor tissue penetration rate. Even low rates of antigen internalization from constitutive membrane turnover can significantly retard antibody penetration. Rapid clearance of single-chain variable fragments also hinders uptake, often more than counterbalancing their more rapid extravasation and diffusion. The model illustrates that with the large resistance from the tumor capillary, antibodies may be more suitable for targeting micrometastases than vascularized tumors.

Cytomegalovirus induced sensorineural hearing loss with persistent cochlear inflammation in neonatal mice

PubMed Central

Schachtele, Scott J.; Mutnal, Manohar B.; Schleiss, Mark R.; Lokensgard, James R.

2011-01-01

Congenital cytomegalovirus (CMV) infection is the leading cause of sensorineural hearing loss (SNHL) in children. During murine (M)CMV-induced encephalitis, the immune response is important for both the control of viral dissemination and the clearance of virus from the brain. While the importance of CMV-induced SNHL has been described, the mechanisms surrounding its pathogenesis and the role of inflammatory responses remain unclear. This study presents a neonatal mouse model of profound SNHL in which MCMV preferentially infected both cochlear perilymphatic epithelial cells and spiral ganglion neurons. Interestingly, MCMV infection induced cochlear hair cell death by 21 days post-infection, despite a clear lack of direct infection of hair cells and the complete clearance of the virus from the cochlea by 14 dpi. Flow cytometric, immunohistochemical, and quantitative PCR analysis of MCMV-infected cochlea revealed a robust and chronic inflammatory response, including a prolonged increase in reactive oxygen species production by infiltrating macrophages. These data support a pivotal role for inflammation during MCMV-induced SNHL. PMID:21416394

Cytomegalovirus-induced sensorineural hearing loss with persistent cochlear inflammation in neonatal mice.

PubMed

Schachtele, Scott J; Mutnal, Manohar B; Schleiss, Mark R; Lokensgard, James R

2011-06-01

Congenital cytomegalovirus (CMV) infection is the leading cause of sensorineural hearing loss (SNHL) in children. During murine (M)CMV-induced encephalitis, the immune response is important for both the control of viral dissemination and the clearance of virus from the brain. While the importance of CMV-induced SNHL has been described, the mechanisms surrounding its pathogenesis and the role of inflammatory responses remain unclear. This study presents a neonatal mouse model of profound SNHL in which MCMV preferentially infected both cochlear perilymphatic epithelial cells and spiral ganglion neurons. Interestingly, MCMV infection induced cochlear hair cell death by 21 days post-infection, despite a clear lack of direct infection of hair cells and the complete clearance of the virus from the cochlea by 14 dpi. Flow cytometric, immunohistochemical, and quantitative PCR analysis of MCMV-infected cochlea revealed a robust and chronic inflammatory response, including a prolonged increase in reactive oxygen species production by infiltrating macrophages. These data support a pivotal role for inflammation during MCMV-induced SNHL.

Transmission-clearance trade-offs indicate that dengue virulence evolution depends on epidemiological context.

PubMed

Ben-Shachar, Rotem; Koelle, Katia

2018-06-15

An extensive body of theory addresses the topic of pathogen virulence evolution, yet few studies have empirically demonstrated the presence of fitness trade-offs that would select for intermediate virulence. Here we show the presence of transmission-clearance trade-offs in dengue virus using viremia measurements. By fitting a within-host model to these data, we further find that the interaction between dengue and the host immune response can account for the observed trade-offs. Finally, we consider dengue virulence evolution when selection acts on the virus's production rate. By combining within-host model simulations with empirical findings on how host viral load affects human-to-mosquito transmission success, we show that the virus's transmission potential is maximized at production rates associated with intermediate virulence and that the optimal production rate critically depends on dengue's epidemiological context. These results indicate that long-term changes in dengue's global distribution impact the invasion and spread of virulent dengue virus genotypes.

IgA is Important for Clearance and Critical for Protection from Rotavirus Infection

PubMed Central

Blutt, Sarah E; Miller, Amber D.; Salmon, Sharon L.; Metzger, Dennis W.; Conner, Margaret E

2012-01-01

Based on a lack of severe phenotype in human IgA deficiency syndromes, the role of IgA in controlling respiratory and gastrointestinal (GI) infections has not been clearly defined. C57BL/6 and BALB/c mice lacking IgA (IgA−/−) were developed and used to address this question. When exposed to a common GI virus, rotavirus, IgA−/− mice exhibited a substantial and significant delay in clearance of the initial infection compared to wild type mice. IgA−/− mice excreted rotavirus in stool up to three weeks after the initial exposure compared to ten days observed in wild type mice. Importantly, IgA−/− mice failed to develop protective immunity against multiple repeat exposures to the virus. All IgA−/− mice excreted virus in the stool upon re-exposure to rotavirus while wild type mice were completely protected against re-infection. These findings clearly indicate a critical role for IgA in the establishment of immunity against a GI viral pathogen. PMID:22739233

Cervical Spine Clearance in Pediatric Trauma Centers: The Need for Standardization and an Evidence-based Protocol.

PubMed

Pannu, Gurpal S; Shah, Mitesh P; Herman, Marty J

Cervical spine clearance in the pediatric trauma patient represents a particularly challenging task. Unfortunately, standardized clearance protocols for pediatric cervical clearance are poorly reported in the literature and imaging recommendations demonstrate considerable variability. With the use of a web-based survey, this study aims to define the methods utilized by pediatric trauma centers throughout North America. Specific attention was given to the identification of personnel responsible for cervical spine care, diagnostic imaging modalities used, and the presence or absence of a written pediatric cervical spine clearance protocol. A 10-question electronic survey was given to members of the newly formed Pediatric Cervical Spine Study Group, all of whom are active POSNA members. The survey was submitted via the online service SurveyMonkey (https://www.surveymonkey.com/r/7NVVQZR). The survey assessed the respondent's institution demographics, such as trauma level and services primarily responsible for consultation and operative management of cervical spine injuries. In addition, respondents were asked to identify the protocols and primary imaging modality used for cervical spine clearance. Finally, respondents were asked if their institution had a documented cervical spine clearance protocol. Of the 25 separate institutions evaluated, 21 were designated as level 1 trauma centers. Considerable variation was reported with regards to the primary service responsible for cervical spine clearance. General Surgery/Trauma (44%) is most commonly the primary service, followed by a rotating schedule (33%), Neurosugery (11%), and Orthopaedic Surgery (8%). Spine consults tend to be seen most commonly by a rotating schedule of Orthopaedic Surgery and Neurosurgery. The majority of responding institutions utilize computed tomographic imaging (46%) as the primary imaging modality, whereas 42% of hospitals used x-ray primarily. The remaining institutions reported using a combination of x-ray and computed tomographic imaging. Only 46% of institutions utilize a written, standardized pediatric cervical spine clearance protocol. This study demonstrates a striking variability in the use of personnel, imaging modalities and, most importantly, standardized protocol in the evaluation of the pediatric trauma patient with a potential cervical spine injury. Cervical spine clearance protocols have been shown to decrease the incidence of missed injuries, minimize excessive radiation exposure, decrease the time to collar removal, and lower overall associated costs. It is our opinion that development of a task force or multicenter research protocol that incorporates existing evidence-based literature is the next best step in improving the care of children with cervical spine injuries. Level 4-economic and decision analyses.

Timing and magnitude of type I interferon responses by distinct sensors impact CD8 T cell exhaustion and chronic viral infection

PubMed Central

Wang, Yaming; Swiecki, Melissa; Cella, Marina; Alber, Gottfried; Schreiber, Robert D; Gilfillan, Susan; Colonna, Marco

2013-01-01

Summary Type I Interferons (IFN-I) promote antiviral CD8+T cell responses, but the contribution of different IFN-I sources and signaling pathways are ill-defined. While plasmacytoid dendritic cells (pDCs) produce IFN-I upon TLR stimulation, IFN-I are induced in most cells by helicases like MDA5. Using acute and chronic lymphocytic choriomeningitis virus (LCMV) infection models, we determined that pDCs transiently produce IFN-I that minimally impacts CD8+T cell responses and viral persistence. Rather, MDA5 is the key sensor that induces IFN-I required for CD8+T cell responses. In the absence of MDA5, CD8+T cell responses to acute infection rely on CD4+T cell help, and loss of both CD4+T cells and MDA5 results in CD8+T cell exhaustion and persistent infection. Chronic LCMV infection rapidly attenuates IFN-I responses, but early administration of exogenous IFN-I rescues CD8+T cells, promoting viral clearance. Thus, effective antiviral CD8+T cell responses depend on the timing and magnitude of IFN-I responses. PMID:22704623

Timing and magnitude of type I interferon responses by distinct sensors impact CD8 T cell exhaustion and chronic viral infection.

PubMed

Wang, Yaming; Swiecki, Melissa; Cella, Marina; Alber, Gottfried; Schreiber, Robert D; Gilfillan, Susan; Colonna, Marco

2012-06-14

Type I interferon (IFN-I) promotes antiviral CD8(+)T cell responses, but the contribution of different IFN-I sources and signaling pathways are ill defined. While plasmacytoid dendritic cells (pDCs) produce IFN-I upon TLR stimulation, IFN-I is induced in most cells by helicases like MDA5. Using acute and chronic lymphocytic choriomeningitis virus (LCMV) infection models, we determined that pDCs transiently produce IFN-I that minimally impacts CD8(+)T cell responses and viral persistence. Rather, MDA5 is the key sensor that induces IFN-I required for CD8(+)T cell responses. In the absence of MDA5, CD8(+)T cell responses to acute infection rely on CD4(+)T cell help, and loss of both CD4(+)T cells and MDA5 results in CD8(+)T cell exhaustion and persistent infection. Chronic LCMV infection rapidly attenuates IFN-I responses, but early administration of exogenous IFN-I rescues CD8(+)T cells, promoting viral clearance. Thus, effective antiviral CD8(+)T cell responses depend on the timing and magnitude of IFN-I production. Copyright © 2012 Elsevier Inc. All rights reserved.

Dynamic Viral Dissemination in Mice Infected with Yellow Fever Virus Strain 17D

PubMed Central

Erickson, Andrea K.

2013-01-01

Arboviruses such as yellow fever virus (YFV) are transmitted between arthropod vectors and vertebrate hosts. While barriers limiting arbovirus population diversity have been observed in mosquitoes, whether barriers exist in vertebrate hosts is unclear. To investigate whether arboviruses encounter bottlenecks during dissemination in the vertebrate host, we infected immunocompetent mice and immune-deficient mice lacking alpha/beta interferon (IFN-α/β) receptors (IFNAR−/− mice) with a pool of genetically marked viruses to evaluate dissemination and host barriers. We used the live attenuated vaccine strain YFV-17D, which contains many mutations compared with virulent YFV. We found that intramuscularly injected immunocompetent mice did not develop disease and that viral dissemination was restricted. Conversely, 32% of intramuscularly injected IFNAR−/− mice developed disease. By following the genetically marked viruses over time, we found broad dissemination in IFNAR−/− mice followed by clearance. The patterns of viral dissemination were similar in mice that developed disease and mice that did not develop disease. Unlike our previous results with poliovirus, these results suggest that YFV-17D encounters no major barriers during dissemination within a vertebrate host in the absence of the type I IFN response. PMID:24027319

Human Papillomaviruses; Epithelial Tropisms, and the Development of Neoplasia

PubMed Central

Egawa, Nagayasu; Egawa, Kiyofumi; Griffin, Heather; Doorbar, John

2015-01-01

Papillomaviruses have evolved over many millions of years to propagate themselves at specific epithelial niches in a range of different host species. This has led to the great diversity of papillomaviruses that now exist, and to the appearance of distinct strategies for epithelial persistence. Many papillomaviruses minimise the risk of immune clearance by causing chronic asymptomatic infections, accompanied by long-term virion-production with only limited viral gene expression. Such lesions are typical of those caused by Beta HPV types in the general population, with viral activity being suppressed by host immunity. A second strategy requires the evolution of sophisticated immune evasion mechanisms, and allows some HPV types to cause prominent and persistent papillomas, even in immune competent individuals. Some Alphapapillomavirus types have evolved this strategy, including those that cause genital warts in young adults or common warts in children. These strategies reflect broad differences in virus protein function as well as differences in patterns of viral gene expression, with genotype-specific associations underlying the recent introduction of DNA testing, and also the introduction of vaccines to protect against cervical cancer. Interestingly, it appears that cellular environment and the site of infection affect viral pathogenicity by modulating viral gene expression. With the high-risk HPV gene products, changes in E6 and E7 expression are thought to account for the development of neoplasias at the endocervix, the anal and cervical transformation zones, and the tonsilar crypts and other oropharyngeal sites. A detailed analysis of site-specific patterns of gene expression and gene function is now prompted. PMID:26193301

Zika plasma viral dynamics in nonhuman primates provides insights into early infection and antiviral strategies

PubMed Central

Best, Katharine; Guedj, Jeremie; Madelain, Vincent; de Lamballerie, Xavier; Lim, So-Yon; Osuna, Christa E.; Whitney, James B.; Perelson, Alan S.

2017-01-01

The recent outbreak of Zika virus (ZIKV) has been associated with fetal abnormalities and neurological complications, prompting global concern. Here we present a mathematical analysis of the within-host dynamics of plasma ZIKV burden in a nonhuman primate model, allowing for characterization of the growth and clearance of ZIKV within individual macaques. We estimate that the eclipse phase for ZIKV, the time between cell infection and viral production, is most likely short (∼4 h), the median within-host basic reproductive number R0 is 10.7, the rate of viral production is rapid (>25,000 virions d−1), and the lifetime of an infected cell while producing virus is ∼5 h. We also estimate that the minimum number of virions produced by an infected cell over its lifetime is ∼5,500. We assess the potential effect of an antiviral treatment that blocks viral replication, showing that the median time to undetectable plasma viral load (VL) can be reduced from ∼5 d to ∼3 d with a drug concentration ∼15 times the drug’s EC50 when treatment is given prophylactically starting at the time of infection. In the case of favipiravir, a polymerase inhibitor with activity against ZIKV, we predict a dose of 150 mg/kg given twice a day initiated at the time of infection can reduce the peak median VL by ∼3 logs and shorten the time to undetectable median VL by ∼2 d, whereas treatment given 2 d postinfection is mostly ineffective in accelerating plasma VL loss in macaques. PMID:28765371

Recurrence of CMV Infection and the Effect of Prolonged Antivirals in Organ Transplant Recipients.

PubMed

Natori, Yoichiro; Humar, Atul; Husain, Shahid; Rotstein, Coleman; Renner, Eberhard; Singer, Lianne; Kim, S Joseph; Kumar, Deepali

2017-06-01

Although initial therapy for cytomegalovirus (CMV) is usually successful, a significant subset of patients may have recurrent viremia. However, the epidemiology and risk factors for recurrence have not been fully defined, as well as the utility of prolonged antivirals after initial clearance. Solid organ transplant patients with first episode of CMV disease or asymptomatic viremia (≥1000 IU/mL) requiring treatment were identified by chart review. Clinical and virologic data were collected. The primary outcome was recurrence of CMV viremia or disease within 6 months of treatment discontinuation. The first episode of CMV viremia requiring antiviral therapy was assessed in 282 patients (147 CMV disease and 135 asymptomatic viremia). Cytomegalovirus occurred at 5.6 (0.63-27.7) months posttransplant. Recurrent CMV occurred in 30.5% patients at a median of 51 (0-160) days after discontinuation of therapy. Factors predictive of recurrence were treatment phase viral kinetics (P = 0.005), lung transplant (P = 0.002), CMV donor (D)+/recipient (R)- serostatus(P = 0.04) and recent acute rejection(P = 0.02). Prolonged antiviral therapy was given to 226 (80.1%) of 282 patients. Recurrence occurred in 73 (32.3%) of 226 patients that received prolonged antivirals versus 13 (23.2%) of 56 in those with no prolonged antivirals (P = 0.19). Recurrent CMV occurs in a significant percentage of patients after treatment of the first episode of CMV viremia/disease. CMV D+/R- serostatus, lung transplant, and treatment phase viral kinetics were significant predictors of recurrence. Continuation of prolonged antivirals beyond initial clearance was not associated with a reduced risk of recurrence.

Preventing vaccinia virus class-I epitopes presentation by HSV-ICP47 enhances the immunogenicity of a TAP-independent cancer vaccine epitope.

PubMed

Raafat, Nermin; Sadowski-Cron, Charlotte; Mengus, Chantal; Heberer, Michael; Spagnoli, Giulio C; Zajac, Paul

2012-09-01

Herpes simplex virus protein ICP47, encoded by US12 gene, strongly downregulates major histocompatibility complex (MHC) class-I antigen restricted presentation by blocking transporter associated with antigen processing (TAP) protein. To decrease viral vector antigenic immunodominance and MHC class-I driven clearance, we engineered recombinant vaccinia viruses (rVV) expressing ICP47 alone (rVV-US12) or together with endoplasmic reticulum (ER)-targeted Melan-A/MART-1(27-35) model tumor epitope (rVV-MUS12). In this study, we show that antigen presenting cells (APC), infected with rVV-US12, display a decreased ability to present TAP dependent MHC class-I restricted viral antigens to CD8+ T-cells. While HLA class-I cell surface expression is strongly downregulated, other important immune related molecules such as CD80, CD44 and, most importantly, MHC class-II are unaffected. Characterization of rVV-MUS12 infected cells demonstrates that over-expression of a TAP-independent peptide, partially compensates for ICP47 induced surface MHC class-I downregulation (30% vs. 70% respectively). Most importantly, in conditions where clearance of infected APC by virus-specific CTL represents a limiting factor, a significant enhancement of CTL responses to the tumor epitope can be detected in cultures stimulated with rVV-MUS12, as compared to those stimulated by rVV-MART alone. Such reagents could become of high relevance in multiple boost protocols required for cancer immunotherapy, to limit vector-specific responsiveness. Copyright © 2011 UICC.

CD70-deficiency impairs effector CD8 T cell generation and viral clearance but is dispensable for the recall response to LCMV

PubMed Central

Munitic, Ivana; Kuka, Mirela; Allam, Atef; Scoville, Jonathan P.; Ashwell, Jonathan D.

2012-01-01

CD27 interactions with its ligand, CD70, are thought to be necessary for optimal primary and memory adaptive immune responses to a variety of pathogens. Thus far all studies addressing the function of the CD27-CD70 axis have been performed either in mice lacking CD27, overexpressing CD70, or in which these receptors were blocked or mimicked by antibodies or recombinant soluble CD70. Because these methods have in some cases led to divergent results, we generated CD70-deficient mice to directly assess its role in vivo. We find that lack of CD70-mediated stimulation during primary responses to LCMV lowered the magnitude of CD8 antigen-specific T cell response, resulting in impaired viral clearance, without affecting CD4 T cell responses. Unexpectedly, CD70-CD27 costimulation was not needed for memory CD8 T cell generation or the ability to mount a recall response to LCMV. Adoptive transfers of wild type (WT) memory T cells into CD70−/− or WT hosts also showed no need for CD70-mediated stimulation during the course of the recall response. Moreover, CD70-expression by CD8 T cells could not rescue endogenous CD70−/− cells from defective expansion, arguing against a role for CD70-mediated T:T help in this model. Therefore, CD70 appears to be an important factor in the initiation of a robust and effective primary response but dispensable for CD8 T cell memory responses. PMID:23269247

Interferon-Free Treatment of Hepatitis C Virus in HIV/Hepatitis C Virus-Coinfected Subjects Results in Increased Serum Low-Density Lipoprotein Concentration

PubMed Central

Townsend, Kerry; Meissner, Eric G.; Sidharthan, Sreetha; Sampson, Maureen; Remaley, Alan T.; Tang, Lydia; Kohli, Anita; Osinusi, Anu; Masur, Henry

2016-01-01

Abstract Chronic hepatitis C virus (HCV) infection is associated with lower serum concentration of low-density lipoprotein (LDL-C), the primary cholesterol metabolite targeted pharmaceutically to modulate cardiovascular risk. Chronic infection with human immunodeficiency virus (HIV) and treatment with antiretrovirals (ARVs) are associated with dyslipidemia and increased risk of cardiovascular disease. In subjects coinfected with HIV and HCV, lipid abnormalities associated with either infection alone are often attenuated. Treatment of chronic HCV infection in HIV/HCV-coinfected subjects is now possible with interferon (IFN)-free regimens composed of directly acting antivirals (DAAs). We previously observed a marked increase in serum LDL-C in HCV-monoinfected subjects treated with sofosbuvir and ribavirin (SOF/RBV) that correlated with viral decline in serum, suggesting a direct influence of HCV clearance on serum cholesterol. In the present study, we assessed longitudinal changes in cholesterol in HIV/HCV-coinfected subjects during treatment of HCV genotype-1 (GT1) infection with combination DAA therapy. We report a rapid increase in LDL-C and LDL particle size by week 2 of treatment that was sustained during and after treatment in HIV/HCV-coinfected subjects. No change in serum LDL-C was observed at day 3 of treatment, in spite of a marked reduction in serum HCV viral load, suggesting LDL-C increases do not directly reflect HCV clearance as measured in peripheral blood. After effective DAA therapy for HCV, an increase in LDL should be anticipated in HIV/HCV-coinfected subjects. PMID:26559180

Uptake of reovirus serotype 1 by the lungs from the bloodstream is mediated by the viral hemagglutinin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verdin, E.M.; Lynn, S.P.; Fields, B.N.

1988-02-01

The authors used the mammalian reoviruses to determine the molecular basis of the clearance of a virus from the bloodstream by specific organs. Reovirus serotypes 1 (T1) and 3 (T3) were radiolabeled with ({sup 35}S)methionine or {sup 125}I, and the viruses were injected intravenously into weanling rats. The distribution of radioactivity within the animals was determined at various times after the injection. Both viruses were cleared rapidly from the bloodstream and concentrated in different organs. Reovirus T1 was found predominantly in the lungs and liver, whereas T3 was found predominantly in the liver, with very little virus in the lungs.more » Using intertypic reassortants, they determined that the T1 S1 gene, which encodes the viral hemagglutinin ({sigma}1 protein), is responsible for the difference in uptake of T1 and T3 by the lungs. The genetic mapping was extended by using several approaches. (i) T1 subjected to limited proteolytic digestion with chymotrypsin was cleared efficiently by the lungs despite the removal of {sigma}3 and digestion of {mu}1C to {delta}. (ii) Uptake of T1 by the lungs was totally inhibited by incubation of T1 with an anti-{sigma}1 monoclonal antibody or its Fab fragment before injection. (iii) A reovirus T1 variant in the {sigma}1 protein was poorly taken up by the lungs. These data indicate that clearance of reovirus from the bloodstream by the lungs is dependent on the presence of the T1 or {sigma}1 protein.« less

Work experience mitigated age-related differences in balance and mobility during surface accommodation.

PubMed

Rietdyk, Shirley; McGlothlin, James D; Knezovich, Mark J

2005-12-01

Locomotor behavior at the roofing worksite is challenged by factors such as sloped surfaces, wind gusts and handling loads. Chronic exposure to this environment may result in enhanced locomotor strategies that are resistant to aging effects. The purpose of this study was to determine if roofers demonstrated enhanced locomotor strategies and if the strategies were maintained with age. The gait of ten younger roofers (mean age 27.2 years), eight older roofers (55.4 years), ten younger controls (25.4 years) and nine older controls (57.6 years) was examined during level gait and stepping up onto a wooden surface (0.15m high). Subjects either carried no load, an empty box or the same box loaded to the equivalent of 5% body mass. Work by age interactions were observed for toe clearance, step width, net angular momentum of the head, arms and trunk segment and gait speed (P<0.0001). Younger roofers demonstrated the greatest toe clearance; older roofers had a smaller lead clearance but decreased variability. Older control groups had the greatest risk of tripping due to low lead toe clearance and high variability, and were least likely to recover if they did trip due to faster gait speed and increased net angular momentum. Work experience resulted in enhanced changes in lead toe clearance and mitigated age-related changes in step width and net angular momentum. Challenging environments show promise for maintaining balance skills in older adults; however care should be taken when introducing inexperienced older adults to a challenging environment.

Viral genetic variation accounts for a third of variability in HIV-1 set-point viral load in Europe

PubMed Central

Wymant, Chris; Cornelissen, Marion; Gall, Astrid; Bakker, Margreet; Bezemer, Daniela; Hall, Matthew; Hillebregt, Mariska; Ong, Swee Hoe; Albert, Jan; Bannert, Norbert; Fellay, Jacques; Fransen, Katrien; Gourlay, Annabelle J.; Grabowski, M. Kate; Gunsenheimer-Bartmeyer, Barbara; Günthard, Huldrych F.; Kivelä, Pia; Kouyos, Roger; Laeyendecker, Oliver; Liitsola, Kirsi; Meyer, Laurence; Porter, Kholoud; Ristola, Matti; van Sighem, Ard; Vanham, Guido; Berkhout, Ben; Kellam, Paul; Reiss, Peter; Fraser, Christophe

2017-01-01

HIV-1 set-point viral load—the approximately stable value of viraemia in the first years of chronic infection—is a strong predictor of clinical outcome and is highly variable across infected individuals. To better understand HIV-1 pathogenesis and the evolution of the viral population, we must quantify the heritability of set-point viral load, which is the fraction of variation in this phenotype attributable to viral genetic variation. However, current estimates of heritability vary widely, from 6% to 59%. Here we used a dataset of 2,028 seroconverters infected between 1985 and 2013 from 5 European countries (Belgium, Switzerland, France, the Netherlands and the United Kingdom) and estimated the heritability of set-point viral load at 31% (CI 15%–43%). Specifically, heritability was measured using models of character evolution describing how viral load evolves on the phylogeny of whole-genome viral sequences. In contrast to previous studies, (i) we measured viral loads using standardized assays on a sample collected in a strict time window of 6 to 24 months after infection, from which the viral genome was also sequenced; (ii) we compared 2 models of character evolution, the classical “Brownian motion” model and another model (“Ornstein–Uhlenbeck”) that includes stabilising selection on viral load; (iii) we controlled for covariates, including age and sex, which may inflate estimates of heritability; and (iv) we developed a goodness of fit test based on the correlation of viral loads in cherries of the phylogenetic tree, showing that both models of character evolution fit the data well. An overall heritability of 31% (CI 15%–43%) is consistent with other studies based on regression of viral load in donor–recipient pairs. Thus, about a third of variation in HIV-1 virulence is attributable to viral genetic variation. PMID:28604782

Adaptive control of theophylline therapy: importance of blood sampling times.

PubMed

D'Argenio, D Z; Khakmahd, K

1983-10-01

A two-observation protocol for estimating theophylline clearance during a constant-rate intravenous infusion is used to examine the importance of blood sampling schedules with regard to the information content of resulting concentration data. Guided by a theory for calculating maximally informative sample times, population simulations are used to assess the effect of specific sampling times on the precision of resulting clearance estimates and subsequent predictions of theophylline plasma concentrations. The simulations incorporated noise terms for intersubject variability, dosing errors, sample collection errors, and assay error. Clearance was estimated using Chiou's method, least squares, and a Bayesian estimation procedure. The results of these simulations suggest that clinically significant estimation and prediction errors may result when using the above two-point protocol for estimating theophylline clearance if the time separating the two blood samples is less than one population mean elimination half-life.

Collaboration of Antibody and Inflammation in Clearance of Rabies Virus from the Central Nervous System

PubMed Central

Hooper, D. Craig; Morimoto, Kinjiro; Bette, Michael; Weihe, Eberhard; Koprowski, Hilary; Dietzschold, Bernhard

1998-01-01

To investigate the involvement of various cellular and humoral aspects of immunity in the clearance of rabies virus from the central nervous system, (CNS), we studied the development of clinical signs and virus clearance from the CNS in knockout mice lacking either B and T cells, CD8+ cytotoxic T cells, B cells, alpha/beta interferon (IFN-α/β) receptors, IFN-γ receptors, or complement components C3 and C4. Following intranasal infection with the attenuated rabies virus CVS-F3, normal adult mice of different genetic backgrounds developed a transient disease characterized by loss of body weight and appetite depression which peaked at 13 days postinfection (p.i.). While these animals had completely recovered by day 21 p.i., mice lacking either B and T cells or B cells alone developed a progressive disease and succumbed to infection. Mice lacking either CD8+ T cells, IFN receptors, or complement components C3 and C4 showed no significant differences in the development of clinical signs by comparison with intact counterparts having the same genetic background. However, while infectious virus and viral RNA could be detected in normal control mice only until day 8 p.i., in all of the gene knockout mice studied except those lacking C3 and C4, virus infection persisted through day 21 p.i. Analysis of rabies virus-specific antibody production together with histological assessment of brain inflammation in infected animals revealed that clearance of CVS-F3 by 21 days p.i. correlated with both a strong inflammatory response in the CNS early in the infection (day 8 p.i.), and the rapid (day 10 p.i.) production of significant levels of virus-neutralizing antibody (VNA). These studies confirm that rabies VNA is an absolute requirement for clearance of an established rabies virus infection. However, for the latter to occur in a timely fashion, collaboration between VNA and inflammatory mechanisms is necessary. PMID:9557653

Impact of power index, hydroureteronephrosis, stone size, and composition on the efficacy of in situ boosted ESWL for primary proximal ureteral calculi.

PubMed

Singh, I; Gupta, N P; Hemal, A K; Dogra, P N; Ansari, M S; Seth, A; Aron, M

2001-07-01

The efficacy, safety, feasibility, and outcome of in situ treatment applied to select proximal ureteral calculi was assessed and analyzed with a view to avoiding auxiliary interventions and providing high clearance rates in the shortest possible time. We studied the impact of several clinically important variables, including power index, degree of hydroureteronephrosis (HDUN), stone size, and composition on the efficacy of sequential in situ boosted extracorporeal shock wave lithotripsy (ESWL) in a select group. The power index requirement for the in situ boosted protocol and the impact of the stone size/composition, degree of HDUN, and clearance rates were also analyzed. An in situ (no instrumentation) boosted protocol was applied to 130 primary unimpacted proximal ureteral calculi with no prior intervention. A typical session with the Siemens Lithostar Plus comprised 3000 shock waves, in installments of 500, deployed at a power setting of 1 to 4 kV with a gradual stepwise escalation. Sequential boosted additional sessions of ESWL were administered on days 2, 7, and 14, tailored to the degree of fragmentation, clearance status, and amount of residual stone bulk. Several parameters (shock waves, kilovolts used, fluoroscopy time, number of sessions, stone size, composition, fragmentation, clearance, and HDUN) were recorded and the results analyzed statistically. The results were excellent in 83.8%, with a mean duration to complete clearance of 11.3 days. In situ ESWL failed in 7.69%, and the auxiliary intervention rate was 10.7%. Pre-ESWL HDUN was present in 78.3%, the mean power index was 184.6/session/case, and the average stone burden was 8.9 mm(2). Calcium oxalate monohydrate was the most common stone (56%). Renal colic was the most common side effect observed. The power index, fragmentation at the first session, and stone size were found to be the most favorable significant variables affecting stone clearance. The degree of HDUN, number of sessions, and stone composition did not significantly impact the clearance rates. In situ boosted ESWL should be the first-line therapeutic modality in select unimpacted primary proximal ureteral stones.

Methadone pharmacogenetics: CYP2B6 polymorphisms determine plasma concentrations, clearance and metabolism

PubMed Central

Kharasch, Evan D.; Regina, Karen J.; Blood, Jane; Friedel, Christina

2015-01-01

Background Interindividual variability in methadone disposition remains unexplained, and methadone accidental overdose in pain therapy is a significant public health problem. Cytochrome P4502B6 (CYP2B6) is the principle determinant of clinical methadone elimination. The CYP2B6 gene is highly polymorphic, with several variant alleles. CYP2B6.6, the protein encoded by the CYP2B6*6 polymorphism, deficiently catalyzes methadone metabolism in vitro. This investigation determined the influence of CYP2B6*6, and other allelic variants encountered, on methadone concentrations, clearance, and metabolism. Methods Healthy volunteers in genotype cohorts CYP2B6*1/*1 (n=21), CYP2B6*1/*6 (n=20), and CYP2B6*6/*6 (n=17), and also CYP2B6*1/*4 (n=1), CYP2B6*4/*6 (n=3), CYP2B6*5/*5 (n=2) subjects received single doses of intravenous and oral methadone. Plasma and urine methadone and metabolite concentrations were determined by tandem mass spectrometry. Results Average S-methadone apparent oral clearance was 35 and 45% lower in CYP2B6*1/*6 and CYP2B6*6/*6 genotypes, respectively, compared with CYP2B6*1/*1, and R-methadone apparent oral clearance was 25 and 30% lower. R- and S-methadone apparent oral clearance was 3- and 4-fold greater in CYP2B6*4 carriers. Intravenous and oral R- and S-methadone metabolism was significantly lower in CYP2B6*6 carriers compared with CYP2B6*1 homozygotes, and greater in CYP2B6*4 carriers. Methadone metabolism and clearance were lower in African-Americans due to the CYP2B6*6 genetic polymorphism. Conclusions CYP2B6 polymorphisms influence methadone plasma concentrations, due to altered methadone metabolism and thus clearance. Genetic influence is greater for oral than intravenous, and S- than R-methadone. CYP2B6 pharmacogenetics explains, in part, interindividual variability in methadone elimination. CYP2B6 genetic effects on methadone metabolism and clearance may identify subjects at risk for methadone toxicity and drug interactions. PMID:26389554

Recent Advances in Non-viral Vectors for Gene Delivery

PubMed Central

Guo, Xia; Huang, Leaf

2011-01-01

CONSPECTUS Non-viral vectors, typically based on cationic lipids or polymers, are preferred due to safety concerns with viral vectors. So far, non-viral vectors can proficiently transfect cells in culture, but obtaining efficient nanomedicines is far from evident. To overcome the hurdles associated with non-viral vectors is significant for improving delivery efficiency and therapeutic effect of nucleic acid. The drawbacks include the strong interaction of cationic delivery vehicles with blood components, uptake by the reticuloendothelial system (RES), toxicity, targeting ability of the carriers to the cells of interest, and so on. PEGylation is the predominant method used to reduce the binding of plasma proteins with non-viral vectors and minimize the clearance by RES after intravenous administration. The nanoparticles that are not rapidly cleared from the circulation accumulate in the tumors due to the enhanced permeability and retention effect, and the targeting ligands attached to the distal end of the PEGylated components allow binding to the receptors on the target cell surface. Neutral or anionic liposomes have been also developed for systemic delivery of nucleic acids in experimental animal model. Designing and synthesizing novel cationic lipids and polymers, and binding nucleic acid with peptides, targeting ligands, polymers, or environmentally sensitive moieties also attract many attentions for resolving the problems encountered by non-viral vectors. The application of inorganic nanoparticles in nucleic acid delivery is an emerging field, too. Recently, different classes of non-viral vectors appear to be converging and the features of different classes of non-viral vectors could be combined in one strategy. More hurdles associated with efficient nucleic acid delivery therefore might be expected to be overcome. In this account, we will focus on these novel non-viral vectors, which are classified into multifunctional hybrid nucleic acid vectors, novel membrane/core nanoparticles for nucleic acid delivery and ultrasound-responsive nucleic acid vectors. The systemic delivery studies are highlighted. Finally, we bring forward the prospect for nucleic acid delivery. We think a better understandings of the fate of the nanoparticles inside the cell and of the interactions between the parts of hybrid particles will lead to a delivery system suitable for clinical use. We also underscore the value of sustained release of nucleic acid and presume making vectors targeted to cells with sustained release in vivo should be an interesting research challenge. PMID:21870813

Determination of low intrinsic clearance in vitro: the benefit of a novel internal standard in human hepatocyte incubations.

PubMed

Zanelli, Ugo; Michna, Thomas; Petersson, Carl

2018-03-26

1. A novel method utilizing an internal standard in hepatocytes incubations has been developed and demonstrated to decrease the variability in the determination of intrinsic clearance (CL int ) in this system. The reduced variability was shown to allow differentiation of lower elimination rate constants from noise. 2. The suggested method was able to compensate for a small but systematic error (0.5 µL/min/10 6 cells) caused by an evaporation of approximately 15% of the volume during the incubation time. 3. The approach was validated using six commercial drugs (ketoprofen, tolbutamide, phenacetin, etodolac and quinidine) which were metabolized by different pathways. 4. The suggested internal standard, MSC1815677, was extensively characterized and the acquired data suggest that it fulfills the requirements of an internal standard present during the incubation. The proposed internal standard was stable during the incubation and showed a low potential to inhibit drug metabolizing enzymes and transporters. With MSC1815677 we propose a novel simple, robust and cost-effective method to address the challenges in the estimation of low clearance in hepatocyte incubations.

Early hepatitis B viral DNA clearance predicts treatment response at week 96

PubMed Central

Fu, Xiao-Yu; Tan, De-Ming; Liu, Cui-Mei; Gu, Bin; Hu, Li-Hua; Peng, Zhong-Tian; Chen, Bin; Xie, Yuan-Lin; Gong, Huan-Yu; Hu, Xiao-Xuan; Yao, Lian-Hui; Xu, Xiao-Ping; Fu, Zheng-Yuan; He, Lang-Qiu; Li, Si-Hai; Long, Yun-Zhu; Li, De-Hui; Gu, Ji-Long; Peng, Shi-Fang

2017-01-01

AIM To investigate whether hepatitis viral DNA load at 24 wk of treatment predicts response at 96 wk in patients with chronic hepatitis B. METHODS A total of 172 hepatitis B envelope antigen (HBeAg)-positive chronic hepatitis B patients who received initial treatment at 16 tertiary hospitals in Hunan Province, China were enrolled in this study. All patients received conventional doses of lamivudine and adefovir dipivoxil, telbivudine, entecavir dispersible tablets, or entecavir tablets for 96 wk. Patients who used other antiviral drugs or antitumor and immune regulation therapy were excluded. Patients were stratified into three groups according to their viral DNA load at 24 wk: < 10 IU/mL (group 1), 10-103 IU/mL (group 2), and > 103 IU/mL (group 3). Correlations of 24-wk DNA load with HBeAg negative status and HBeAg seroconversion at 96 wk were analyzed. Receiver operating characteristic curve analysis was used to test the predictive value of the HBV DNA load at 24 wk for long-term response. RESULTS The rates of conversion to HBeAg negative status and HBeAg seroconversion rates were 53.7% and 51.9%, respectively, in group 1; 35.21% and 32.39% in group 2; and 6.38% and 6.38% in group 3. The receiver operating characteristic curves for the three subgroups revealed that the lowest DNA load (< 10 IU/mL) was better correlated with response at 96 wk than a higher DNA load (10-103 IU/mL). Nested PCR was used for amplifying and sequencing viral DNA in patients with a viral DNA load > 200 IU/mL at 96 wk; resistance mutations involving different loci were present in 26 patients, and three of these patients had a viral DNA load 10-103 IU/mL at 96 wk. CONCLUSION Hepatitis B viral DNA load at 24 wk of antiviral treatment in patients with chronic hepatitis B is a predictor of the viral load and response rate at 96 wk. PMID:28522916

Understanding Local Spatial Variation Along the Care Continuum: The Potential Impact of Transportation Vulnerability on HIV Linkage to Care and Viral Suppression in High-Poverty Areas, Atlanta, Georgia.

PubMed

Goswami, Neela D; Schmitz, Michelle M; Sanchez, Travis; Dasgupta, Sharoda; Sullivan, Patrick; Cooper, Hannah; Rane, Deepali; Kelly, Jane; Del Rio, Carlos; Waller, Lance A

2016-05-01

Engagement in care is central to reducing mortality for HIV-infected persons and achieving the White House National AIDS Strategy of 80% viral suppression in the US by 2020. Where an HIV-infected person lives impacts his or her ability to achieve viral suppression. Reliable transportation access for healthcare may be a key determinant of this place-suppression relationship. ZIP code tabulation areas (ZCTAs) were the units of analysis. We used geospatial and ecologic analyses to examine spatial distributions of neighborhood-level variables (eg, transportation accessibility) and associations with: (1) community linkage to care, and (2) community viral suppression. Among Atlanta ZCTAs with data for newly diagnosed HIV cases (2006-2010), we used Moran I to evaluate spatial clustering and linear regression models to evaluate associations between neighborhood variables and outcomes. In 100 ZCTAs with 8413 newly diagnosed HIV-positive residents, a median of 60 HIV cases were diagnosed per ZCTA during the 5-year period. We found significant clustering of ZCTAs with low linkage to care and viral suppression (Moran I = 0.218, P < 0.05). In high-poverty ZCTAs, a 10% point increase in ZCTA-level household vehicle ownership was associated with a 4% point increase in linkage to care (P = 0.02, R = 0.16). In low-poverty ZCTAs, a 10% point increase in ZCTA-level household vehicle ownership was associated with a 30% point increase in ZCTA-level viral suppression (P = 0.01, R = 0.08). Correlations between transportation variables and community-level care linkage and viral suppression vary by area poverty level and provide opportunities for interventions beyond individual-level factors.

Immune responses to West Nile virus infection in the central nervous system.

PubMed

Cho, Hyelim; Diamond, Michael S

2012-12-17

West Nile virus (WNV) continues to cause outbreaks of severe neuroinvasive disease in humans and other vertebrate animals in the United States, Europe, and other regions of the world. This review discusses our understanding of the interactions between virus and host that occur in the central nervous system (CNS), the outcome of which can be protection, viral pathogenesis, or immunopathogenesis. We will focus on defining the current state of knowledge of WNV entry, tropism, and host immune response in the CNS, all of which affect the balance between injury and successful clearance.

Exploring viral infection using single-cell sequencing.

PubMed

Rato, Sylvie; Golumbeanu, Monica; Telenti, Amalio; Ciuffi, Angela

2017-07-15

Single-cell sequencing (SCS) has emerged as a valuable tool to study cellular heterogeneity in diverse fields, including virology. By studying the viral and cellular genome and/or transcriptome, the dynamics of viral infection can be investigated at single cell level. Most studies have explored the impact of cell-to-cell variation on the viral life cycle from the point of view of the virus, by analyzing viral sequences, and from the point of view of the cell, mainly by analyzing the cellular host transcriptome. In this review, we will focus on recent studies that use single-cell sequencing to explore viral diversity and cell variability in response to viral replication. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

The innate immune response to RSV: Advances in our understanding of critical viral and host factors.

PubMed

Sun, Yan; López, Carolina B

2017-01-11

Respiratory syncytial virus (RSV) causes mild to severe respiratory illness in humans and is a major cause of hospitalizations of infants and the elderly. Both the innate and the adaptive immune responses contribute to the control of RSV infection, but despite successful viral clearance, protective immunity against RSV re-infection is usually suboptimal and infections recur. Poor understanding of the mechanisms limiting the induction of long-lasting immunity has delayed the development of an effective vaccine. The innate immune response plays a critical role in driving the development of adaptive immunity and is thus a crucial determinant of the infection outcome. Advances in recent years have improved our understanding of cellular and viral factors that influence the onset and quality of the innate immune response to RSV. These advances include the identification of a complex system of cellular sensors that mediate RSV detection and stimulate transcriptome changes that lead to virus control and the discovery that cell stress and apoptosis participate in the control of RSV infection. In addition, it was recently demonstrated that defective viral genomes (DVGs) generated during RSV replication are the primary inducers of the innate immune response. Newly discovered host pathways involved in the innate response to RSV, together with the potential generation of DVG-derived oligonucleotides, present various novel opportunities for the design of vaccine adjuvants able to induce a protective response against RSV and similar viruses. Copyright © 2016 Elsevier Ltd. All rights reserved.

Herpes Zoster reactivation in patients with chronic hepatitis C under treatment with directly acting antiviral agents: A case series.

PubMed

El Kassas, Mohamed; Wifi, Mohamed Naguib; Mahdy, Reem; Afify, Shimaa; Hafez, Enas; El Latif, Yasmeen Abd; Ezzat, Marwa; El Tahan, Adel; Youssef, Naglaa; Esmat, Gamal

2017-03-01

We report a series of cutaneous Herpes Zoster (HZ) reactivation cases in patients with hepatitis C virus (HCV) infection treated with directly acting antiviral (DAA) agents. Five cases were detected among 2133 treated patients with DAAs at one of the specialized viral hepatitis treatment centers in Egypt. A control group including 2300 age and sex matched HCV patients who were previously treated with pegylated interferon and ribavirin did not show any HZ reactivation reports while on treatment. None of cases had an evidence of immunosuppression or a risk factor for HZ reactivation. The DAAs used regimens were sofosbuvir/daclatasvir in 4 cases and sofosbuvir/simeprevir in one case. HCV clearance with antiviral therapy may bring immune changes causing reactivation of other latent viral infections like HZ. A high index of clinical suspicion may be needed to guarantee early and prompt management of such cases. Copyright © 2017 Pan-Arab Association of Gastroenterology. Published by Elsevier B.V. All rights reserved.

The hepatitis C virus enigma.

PubMed

Myrmel, Helge; Ulvestad, Elling; Asjø, Birgitta

2009-05-01

Hepatitis C virus (HCV) has a high propensity to establish chronic infection with end-stage liver disease. The high turnover of virus particles and high transcription error rates due to lack of proof-reading function of the viral polymerase imply that HCV exists as quasispecies, thus enabling the virus to evade the host immune response. Clearance of the virus is characterized by a multispecific, vigorous and persistent T-cell response, whereas T-cell responses are weak, narrow and transient in patients who develop chronic infection. At present, standard treatment is a combination of pegylated interferon-alpha and ribavirin, with a sustained viral response rate of 40-80%, depending on genotype. The mechanisms for the observed synergistic effects of the two drugs are still not known in detail, but in addition to direct antiviral mechanisms, the immunomodulatory effects of both drugs seem to be important, with a shift from Th2- to Th1-cytokine profiles in successfully treated patients. This article describes virus-host relations in the natural course of HCV infection and during treatment.

18F-FDG as an inflammation biomarker for imaging dengue virus infection and treatment response

PubMed Central

Watanabe, Satoru; Herr, Keira J.; Kalimuddin, Shirin; Tham, Jing Yang; Ong, Joanne; Reolo, Marie; Serrano, Raymond M.F.; Cheung, Yin Bun; Low, Jenny G.H.; Vasudevan, Subhash G.

2017-01-01

Development of antiviral therapy against acute viral diseases, such as dengue virus (DENV), suffers from the narrow window of viral load detection in serum during onset and clearance of infection and fever. We explored a biomarker approach using 18F-fluorodeoxyglucose (18F-FDG) PET in established mouse models for primary and antibody-dependent enhancement infection with DENV. 18F-FDG uptake was most prominent in the intestines and correlated with increased virus load and proinflammatory cytokines. Furthermore, a significant temporal trend in 18F-FDG uptake was seen in intestines and selected tissues over the time course of infection. Notably, 18F-FDG uptake and visualization by PET robustly differentiated treatment-naive groups from drug-treated groups as well as nonlethal from lethal infections with a clinical strain of DENV2. Thus, 18F-FDG may serve as a novel DENV infection–associated inflammation biomarker for assessing treatment response during therapeutic intervention trials. PMID:28469088

The diagnosis and management of respiratory viral infections in cystic fibrosis.

PubMed

Flight, William; Jones, Andrew

2017-03-01

Respiratory viruses, such as those that cause influenza and the common cold, are a regular feature of life for the entire human population. Among people with CF, these viruses are associated with prolonged respiratory illness and show a clear association with pulmonary exacerbations which in turn are associated with lung function decline and risk of death. Human rhinovirus is the most commonly encountered respiratory viral pathogen in CF although adenovirus, bocavirus, coronavirus, influenza, parainfluenza, metapneumovirus and respiratory syncytial virus are all also responsible for infections in this population. Areas covered: This article reviews the epidemiology, clinical impact and therapeutic options for respiratory virus infection in both children and adults with CF. Expert commentary: The management of CF to date has largely focused on airway clearance strategies, nutritional support and aggressive antibacterial therapy. We highlight the significant role that respiratory viruses play in CF lung disease and argue that these pathogens represent an under-exploited target in the battle to control patients' symptoms and disease progression.

Interleukin-17A Promotes CD8+ T Cell Cytotoxicity To Facilitate West Nile Virus Clearance.

PubMed

Acharya, Dhiraj; Wang, Penghua; Paul, Amber M; Dai, Jianfeng; Gate, David; Lowery, Jordan E; Stokic, Dobrivoje S; Leis, A Arturo; Flavell, Richard A; Town, Terrence; Fikrig, Erol; Bai, Fengwei

2017-01-01

CD8 + T cells are crucial components of immunity and play a vital role in recovery from West Nile virus (WNV) infection. Here, we identify a previously unrecognized function of interleukin-17A (IL-17A) in inducing cytotoxic-mediator gene expression and promoting CD8 + T cell cytotoxicity against WNV infection in mice. We find that IL-17A-deficient (Il17a -/- ) mice are more susceptible to WNV infection and develop a higher viral burden than wild-type (WT) mice. Interestingly, the CD8 + T cells isolated from Il17a -/- mice are less cytotoxic and express lower levels of cytotoxic-mediator genes, which can be restored by supplying recombinant IL-17A in vitro and in vivo Importantly, treatment of WNV-infected mice with recombinant IL-17A, as late as day 6 postinfection, significantly reduces the viral burden and increases survival, suggesting a therapeutic potential for IL-17A. In conclusion, we report a novel function of IL-17A in promoting CD8 + T cell cytotoxicity, which may have broad implications in other microbial infections and cancers. Interleukin-17A (IL-17A) and CD8 + T cells regulate diverse immune functions in microbial infections, malignancies, and autoimmune diseases. IL-17A is a proinflammatory cytokine produced by diverse cell types, while CD8 + T cells (known as cytotoxic T cells) are major cells that provide immunity against intracellular pathogens. Previous studies have demonstrated a crucial role of CD8 + T cells in recovery from West Nile virus (WNV) infection. However, the role of IL-17A during WNV infection remains unclear. Here, we demonstrate that IL-17A protects mice from lethal WNV infection by promoting CD8 + T cell-mediated clearance of WNV. In addition, treatment of WNV-infected mice with recombinant IL-17A reduces the viral burden and increases survival of mice, suggesting a potential therapeutic. This novel IL-17A-CD8 + T cell axis may also have broad implications for immunity to other microbial infections and cancers, where CD8 + T cell functions are crucial. Copyright © 2016 American Society for Microbiology.

Using an agent-based model to analyze the dynamic communication network of the immune response

PubMed Central

2011-01-01

Background The immune system behaves like a complex, dynamic network with interacting elements including leukocytes, cytokines, and chemokines. While the immune system is broadly distributed, leukocytes must communicate effectively to respond to a pathological challenge. The Basic Immune Simulator 2010 contains agents representing leukocytes and tissue cells, signals representing cytokines, chemokines, and pathogens, and virtual spaces representing organ tissue, lymphoid tissue, and blood. Agents interact dynamically in the compartments in response to infection of the virtual tissue. Agent behavior is imposed by logical rules derived from the scientific literature. The model captured the agent-to-agent contact history, and from this the network topology and the interactions resulting in successful versus failed viral clearance were identified. This model served to integrate existing knowledge and allowed us to examine the immune response from a novel perspective directed at exploiting complex dynamics, ultimately for the design of therapeutic interventions. Results Analyzing the evolution of agent-agent interactions at incremental time points from identical initial conditions revealed novel features of immune communication associated with successful and failed outcomes. There were fewer contacts between agents for simulations ending in viral elimination (win) versus persistent infection (loss), due to the removal of infected agents. However, early cellular interactions preceded successful clearance of infection. Specifically, more Dendritic Agent interactions with TCell and BCell Agents, and more BCell Agent interactions with TCell Agents early in the simulation were associated with the immune win outcome. The Dendritic Agents greatly influenced the outcome, confirming them as hub agents of the immune network. In addition, unexpectedly high frequencies of Dendritic Agent-self interactions occurred in the lymphoid compartment late in the loss outcomes. Conclusions An agent-based model capturing several key aspects of complex system dynamics was used to study the emergent properties of the immune response to viral infection. Specific patterns of interactions between leukocyte agents occurring early in the response significantly improved outcome. More interactions at later stages correlated with persistent inflammation and infection. These simulation experiments highlight the importance of commonly overlooked aspects of the immune response and provide insight into these processes at a resolution level exceeding the capabilities of current laboratory technologies. PMID:21247471

Hepatitis C Virus in the US Military Retiree Population: To Screen, or Not to Screen?

PubMed

Laufer, Christin B; Carroll, Matthew B

2015-10-01

In 2012, the Centers for Disease Control (CDC) recommended hepatitis C virus (HCV) screening for those born between 1945 and 1965. Prior recommendations endorsed screening based on risk factors (RFs). Because United States (US) military retirees have had at least 20 years of access to free comprehensive health care, mandatory physical fitness tests, periodic health assessments and mandatory drug screening, we hypothesized that the prevalence of HCV amongst military retirees is lower than the national average. Thus the new CDC screening guidelines may not be applicable or cost effective in this particular population. A quality improvement (QI) initiative implemented the new birth-cohort CDC screening guidelines for the internal medicine (IM) clinic of our hospital (QI group). An age-matched group from the same IM clinic, screened based on RFs for HCV infection, served as the comparator (RF group). The prevalence of the anti-HCV antibody and chronic infection was determined and compared with each other and with the national average. The prevalence of the HCV antibody was 2.1% and 2.3% in the QI and RF groups, respectively (odds ratio (OR): 1.08, 95% CI: 0.37 - 3.21, P = 1.000). The prevalence of chronic infection was 0.4% and 1.8% in the QI and RF groups, respectively (OR: 4.39, 95% CI: 0.80 - 24.13, P = 0.083). When our data were compared with the national average, there were no statistical differences in the prevalence of the HCV antibody; however, there was statistically more viral clearance, and subsequently less chronic infection, in the QI group versus the national average. The military retiree population did not have a lower prevalence of the HCV antibody than the American populace whether screened based on age or traditional RFs. Thus, the CDC guidelines are applicable in this population. One interesting finding of this study is the higher rate of viral clearance in military retirees when compared with the national average. It is therefore possible that military retirees may be more likely to have natural viral eradication than the civilian population.

Characterization of hepatitis B virus surface antigen variability and impact on HBs antigen clearance under nucleos(t)ide analogue therapy.

PubMed

Velay, A; Jeulin, H; Eschlimann, M; Malvé, B; Goehringer, F; Bensenane, M; Frippiat, J-P; Abraham, P; Ismail, A M; Murray, J M; Combet, C; Zoulim, F; Bronowicki, J-P; Schvoerer, E

2016-05-01

For hepatitis B virus (HBV)-related chronic infection under treatment by nucleos(t)ide analogues (NUCs), HBsAg clearance is the ultimate therapeutic goal but very infrequent. We investigated how HBV envelope protein variability could lead to differential HBsAg clearance on NUCs. For 12 HBV genotype D patients receiving NUCs, six resolvers (HBsAg clearance) were compared to six matched nonresolvers (HBsAg persistence). PreS/S amino acid (aa) sequences were analysed with bioinformatics to predict HBV envelope antigenicity and aa covariance. To enrich our analyses on very rare resolvers, these were compared with other HBV genotype D strains in three characterized clinical cohorts including common chronically infected patients. The sT125M+sP127T combination was observed in four nonresolvers of six, corroborated by aa covariance analysis, associated with a lower predicted antigenicity than sT125T+sP127P. Concordant features within this HBV key functional domain, at positions 125 and 127, were reported from two of the three comparative cohorts. In our hands, a lower ELISA reactivity of HBV-vaccinated mice sera was observed against the sT125M mutant. In the S gene, 56 aa changes in minor variants were detected in non-resolvers, mainly in the major hydrophilic region, vs 28 aa changes in resolvers. Molecular features in patients showing HBsAg persistence on NUCs argue in favour of a different aa pattern in the HBV S gene compared to those showing HBsAg clearance. In nonresolvers, a decrease in HBs 'a' determinant antigenicity and more frequent mutations in the S gene suggest a role for the HBV envelope characteristics in HBsAg persistence. © 2016 John Wiley & Sons Ltd.

Natural History of Helicobacter pylori Infection in Mexican Schoolchildren: Incidence and Spontaneous Clearance

PubMed Central

Duque, Ximena; Vilchis, Jenny; Mera, Robertino; Trejo-Valdivia, Belem; Goodman, Karen J.; Mendoza, Maria-Eugenia; Navarro, Fabiola; Roque, Victoria; Moran, Segundo; Torres, Javier; Correa, Pelayo

2013-01-01

Objectives The aim of the present study was to estimate the incidence and spontaneous clearance rate of Helicobacter pylori infection and the effect of some variables on these outcomes in schoolchildren. Methods From May 2005 to December 2010, 718 schoolchildren enrolled in 3 public boarding schools in Mexico City participated in the follow-up. At the beginning of the study and every 6 months thereafter, breath samples were taken to detect H pylori infection; blood samples and anthropometric measurements were taken to evaluate nutritional status. Data on sociodemographic characteristics were collected. Results The prevalence of H pylori infection was 38%. The incidence rate was 6.36%/year. Schoolchildren with anemia or iron deficiency at the beginning of the study (who received iron supplements) showed a higher infection acquisition rate than those with normal iron nutritional status, hazard ratio (HR) 12.52 (95% confidence interval [CI] 4.01%–39.12%), P <0.001 and HR 2.05 (95% CI 1.09%–3.87%), P = 0.027, respectively. The spontaneous clearance rate of the infection was 4.74%/year. The spontaneous clearance rate was higher in children who had iron deficiency (who received iron supplements), HR 5.02 (95% CI 1.33%–18.99%), P = 0.017, compared with those with normal nutritional iron status. It was lower in schoolchildren with ≥2 siblings compared with schoolchildren with 1 or no siblings, HR 0.23 (95% CI 0.08%–0.63%), P = 0.004. Conclusions H pylori infection status is dynamic in schoolchildren. Variables related to health status and infection transmission, such as iron status and number of siblings, are important for the incidence and spontaneous clearance of H pylori infection. PMID:22227999

Serum cystatin C: a surrogate marker for the characteristics of peritoneal membrane in dialysis patients.

PubMed

Al-Wakeel, Jamal S; Hammad, Durdana; Memon, Nawaz Ali; Tarif, Nauman; Shah, Iqbal; Chaudhary, Abdulrauf

2009-03-01

To evaluate whether cystatin C levels can be a surrogate marker of creatinine clearance and reflect the characteristics of peritoneal membrane in dialysis patients, we performed peritoneal equilibration tests (PET) in 18 anuric adult chronic peritoneal dialysis (PD) patients with a mean age of 39.7 +/- 20 years. All the samples were analyzed for urea, creatinine, and cystatin C. Peritoneal transport, mass transfer, and peritoneal clearance of cystatin C were calculated. Correlation and regression analysis was done using cystatin C as a dependent variable and age, sex, height, weight, body surface area, and creatinine as independent variables. Cystatin C demonstrated a significant time dependent increase of dialysate concentration and decline in the serum concentrations during PET, and a strong correlation between serum creatinine and serum cystatin C concentrations(r: 0.62, p= 0.008). The trans-peritoneal clearance (mL/min/1.73 m 2 ) of cystatin C was related to its serum concentration and was similar to creatinine in its pattern but of smaller magnitude. Peritoneal mass transfer (mg/4 hr per 1.73 m 2 ) for cystatin C serum creatinine was 1.68 +/- 0.67 and 73.3 +/- 29.8, respectively. The dialysis/plasma D/P cystatin C concentration was > or = 0.1 at 4 hrs of PET denoted high peritoneal transport, while the values of < 0.1 denoted low transport type. We conclude that cystatin C follows the same pattern of peritoneal exchange as creatinine but the magnitude of transfer is many folds lower than creatinine. At present clinical utility of cystatin C in the evaluation of solute clearance is probably limited due to the minute amounts transferred across the membrane and the high renal clearance in the presence of residual renal function.

Population Pharmacokinetics of Ceftizoxime Administered by Continuous Infusion in Clinically Ill Adult Patients

PubMed Central

Facca, Bryan; Frame, Bill; Triesenberg, Steve

1998-01-01

Ceftizoxime is a widely used beta-lactam antimicrobial agent, but pharmacokinetic data for use with clinically ill patients are lacking. We studied the population pharmacokinetics of ceftizoxime in 72 clinically ill patients at a community-based, university-affiliated hospital. A population pharmacokinetic model for ceftizoxime was created by using a prospective observational design. Ceftizoxime was administered by continuous infusion to treat patients with proven or suspected bacterial infections. While the patients were receiving infusions of ceftizoxime, serum samples were collected for pharmacokinetic analysis with the nonlinear mixed-effect modeling program NONMEM. In addition to clearance and volume of distribution, various comorbidities were examined for their influence on the kinetics. All 72 subjects completed the study, and 114 serum samples were collected. Several demographic and comorbidity variables, namely, age, weight, serum creatinine levels, congestive heart failure, and long-term ventilator dependency, had a significant impact on the estimate for ceftizoxime clearance. A mixture model, or two populations for estimation of ceftizoxime clearance, was discovered. One population presented with an additive clearance component of 1.6 liters per h. In addition, a maximizer function for serum creatinine levels was found. In summary, two models for ceftizoxime clearance, mixture and nonmixture, were found and are presented. Clearance for ceftizoxime can be estimated with commonly available clinical information and the models presented. From the clearance estimates, the dose of ceftizoxime to maintain the desired concentration in serum can be determined. Work is needed to validate the model for drug clearance and to evaluate its predictive performance. PMID:9661021

Principles underlying the epizootiology of viral hemorrhagic septicemia in Pacific herring and other fishes throughout the North Pacific Ocean

USGS Publications Warehouse

Hershberger, Paul K.; Garver, Kyle A.; Winton, James R.

2016-01-01

Although viral hemorrhagic septicemia virus (VHSV) typically occurs at low prevalence and intensity in natural populations of Pacific herring (Clupea pallasii) and other marine fishes in the Northeast Pacific Ocean, epizootics of the resulting disease (VHS) periodically occur, often in association with observed fish kills. Here we identify a list of principles, based on a combination of field studies, controlled laboratory experiments, and previously unpublished observations, that govern the epizootiology of VHS in Pacific herring. A thorough understanding of these principles provides the basis for identifying risk factors that predispose certain marine fish populations to VHS epizootics, including the lack of population resistance, presence of chronic viral carriers in a population, copious viral shedding by infected individuals, cool water temperatures, limited water circulation patterns, and gregarious host behavioral patterns. Further, these principles are used to define the epizootiological stages of the disease in Pacific herring, including the susceptible (where susceptible individuals predominate a school or subpopulation), enzootic (where infection prevalence and intensity are often below the limits of reasonable laboratory detection), disease amplification (where infection prevalence and intensity increase rapidly), outbreak (often accompanied by host mortalities with high virus loads and active shedding), recovery (in which the mortality rate and virus load decline owing to an active host immune response), and refractory stages (characterized by little or no susceptibility and where viral clearance occurs in most VHS survivors). In addition to providing a foundation for quantitatively assessing the potential risks of future VHS epizootics in Pacific herring, these principles provide insights into the epizootiology of VHS in other fish communities where susceptible species exist.

Chemokine Receptor Ccr7 Restricts Fatal West Nile Virus Encephalitis.

PubMed

Bardina, Susana V; Brown, Julia A; Michlmayr, Daniela; Hoffman, Kevin W; Sum, Janet; Pletnev, Alexander G; Lira, Sergio A; Lim, Jean K

2017-05-15

West Nile virus (WNV) is a mosquito-transmitted flavivirus that can cause debilitating encephalitis. To delineate the mechanisms behind this pathology, we studied Ccr7-deficient mice, which afforded us the capacity to study infection in mice with disrupted peripheral cellular trafficking events. The loss of Ccr7 resulted in an immediate pan-leukocytosis that remained elevated throughout the infection. This leukocytosis resulted in a significant enhancement of leukocyte accumulation within the central nervous system (CNS). Despite an excess of virus-specific T cells in the CNS, Ccr7-deficient mice had significantly higher CNS viral loads and mortality rates than wild-type animals. Mechanistically, the elevated trafficking of infected myeloid cells into the brain in Ccr7-deficient mice resulted in increased levels of WNV in the CNS, thereby effectively contributing to neuroinflammation and lowering viral clearance. Combined, our experiments suggest that during WNV infection, Ccr7 is a gatekeeper for nonspecific viral transference to the brain. IMPORTANCE In this study, we show that Ccr7 is required for the sufficient migration of dendritic cells and T cells into the draining lymph node immediately following infection and for the restriction of leukocyte migration into the brain. Further, the severe loss of dendritic cells in the draining lymph node had no impact on viral replication in this organ, suggesting that WNV may migrate from the skin into the lymph node through another mechanism. Most importantly, we found that the loss of Ccr7 results in a significant leukocytosis, leading to hypercellularity within the CNS, where monocytes/macrophages contribute to CNS viremia, neuroinflammation, and increased mortality. Together, our data point to Ccr7 as a critical host defense restriction factor limiting neuroinflammation during acute viral infection. Copyright © 2017 American Society for Microbiology.

Variable Selection through Correlation Sifting

NASA Astrophysics Data System (ADS)

Huang, Jim C.; Jojic, Nebojsa

Many applications of computational biology require a variable selection procedure to sift through a large number of input variables and select some smaller number that influence a target variable of interest. For example, in virology, only some small number of viral protein fragments influence the nature of the immune response during viral infection. Due to the large number of variables to be considered, a brute-force search for the subset of variables is in general intractable. To approximate this, methods based on ℓ1-regularized linear regression have been proposed and have been found to be particularly successful. It is well understood however that such methods fail to choose the correct subset of variables if these are highly correlated with other "decoy" variables. We present a method for sifting through sets of highly correlated variables which leads to higher accuracy in selecting the correct variables. The main innovation is a filtering step that reduces correlations among variables to be selected, making the ℓ1-regularization effective for datasets on which many methods for variable selection fail. The filtering step changes both the values of the predictor variables and output values by projections onto components obtained through a computationally-inexpensive principal components analysis. In this paper we demonstrate the usefulness of our method on synthetic datasets and on novel applications in virology. These include HIV viral load analysis based on patients' HIV sequences and immune types, as well as the analysis of seasonal variation in influenza death rates based on the regions of the influenza genome that undergo diversifying selection in the previous season.

Study for Air Vehicles at High Speeds, Identifying the Potential Benefits to Transport Aircraft of a Continuously Variable Geometry Trailing-Edge Structure that can be Utilized for Aircraft Control, Trim, Load-Alleviation, and High Lift

DTIC Science & Technology

2011-08-01

Field Length is defined as the total distance from brake release to the point at which the aircraft clears a height of 35 ft. The clearance height is...height clearance. The AEFL comprises two parts, the ground roll from brake release to lift-off (GR) plus the distance from lift-off to 35 ft height

Genotype-phenotype associations for common CYP3A4 and CYP3A5 variants in the basal and induced metabolism of midazolam in European- and African-American men and women.

PubMed

Floyd, Michael D; Gervasini, Guillermo; Masica, Andrew L; Mayo, Gail; George, Alfred L; Bhat, Kolari; Kim, Richard B; Wilkinson, Grant R

2003-10-01

CYP3A activity in adults varies between individuals and it has been suggested that this has a genetic basis, possibly related to variant alleles in CYP3A4 and CYP3A5 genes. Accordingly, genotype-phenotype associations were investigated under constitutive and induced conditions. Midazolam's systemic and oral clearances, and the erythromycin breath test (ERBT) were determined in 57 healthy subjects: 23 (11 men, 12 women) European- and 34 (14 men, 20 women) African-Americans. Studies were undertaken in the basal state and after 14-15 days pretreatment with rifampin. DNA was characterized for the common polymorphisms CYP3A4*1B, CYP3A5*3, CYP3A5*6 and CYP3A5*7 by direct sequencing, and for exon 21 and exon 26 variants of MDR1 by allele-specific, real-time polymerase chain reaction. In 95% of subjects, the basal systemic clearance of midazolam was unimodally distributed and variability was less than four-fold whereas, in 98% of the study population, oral clearance varied five-fold. No population or sex-related differences were apparent. Similar findings were observed with the ERBT. Rifampin pretreatment markedly increased the systemic (two-fold) and oral clearance (16-fold) of midazolam, and the ERBT (two-fold) but the variabilities were unchanged. No associations were noted between these phenotypic measures and any of the studied genotypes, except for oral clearance and its fold-increase after rifampin. These were related to the presence of CYP3A4*1B and the inversely linked CYP3A5*3 polymorphism, with the extent of induction being approximately 50% greater in CYP3A5*3 homozygotes compared to wild-type subjects. In most healthy subjects, variability in intestinal and hepatic CYP3A activity, using midazolam as an in-vivo probe, is modest and common polymorphisms in CYP3A4 and CYP3A5 do not appear to have important functional significance.

Impact of hepatitis C oral therapy in portal hypertension.

PubMed

Libânio, Diogo; Marinho, Rui Tato

2017-07-14

Chronic hepatitis C is a leading cause of morbidity and mortality, mainly related to fibrosis/cirrhosis and portal hypertension. Direct antiviral agents are highly effective and safe and can now cure > 90% of the patients. Sustained viral response (SVR) after interferon-based regimens has been associated with improvement in liver function, fibrosis and portal hypertension in a significant proportion of patients, although a point of no return seems to exist from which viral elimination is no longer capable of preventing portal hypertension progression and liver decompensation. Indeed, although SVR is associated with improvement of hepatic venous pressure gradients and therefore a decreased risk of de novo esophageal varices, several studies show that viral clearance does not eliminate the risk of variceal progression, liver decompensation and death in patients with pre-established portal hypertension. Although evidence about the effects of direct antiviral agents (DAAs) on clinically significant outcomes is still scarce and with short follow-up, DAAs can decrease the burden of the disease if patients are timely treated before significant fibrosis and portal hypertension develops. Studies with longer follow-up are waited to establish the real magnitude of hepatitis C treatment on portal hypertension. Future studies should also focus on predictors of portal hypertension resolution since it can influence management and avoid unnecessary monitoring.

Large-scale distribution of microbial and viral populations in the South Atlantic Ocean.

PubMed

De Corte, Daniele; Sintes, Eva; Yokokawa, Taichi; Lekunberri, Itziar; Herndl, Gerhard J

2016-04-01

Viruses are abundant, diverse and dynamic components of the marine environments and play a significant role in the ocean biogeochemical cycles. To assess potential variations in the relation between viruses and microbes in different geographic regions and depths, viral and microbial abundance and production were determined throughout the water column along a latitudinal transect in the South Atlantic Ocean. Path analysis was used to examine the relationships between several abiotic and biotic parameters and the different microbial and viral populations distinguished by flow cytometry. The depth-integrated contribution of microbial and viral abundance to the total microbial and viral biomass differed significantly among the different provinces. Additionally, the virus-to-microbe ratio increased with depth and decreased laterally towards the more productive regions. Our data revealed that the abundance of phytoplankton and microbes is the main controlling factor of the viral populations in the euphotic and mesopelagic layers, whereas in the bathypelagic realm, viral abundance was only weakly related to the biotic and abiotic variables. The relative contribution of the three viral populations distinguished by flow cytometry showed a clear geographical pattern throughout the water column, suggesting that these populations are composed of distinct taxa able to infect specific hosts. Overall, our data indicate the presence of distinct microbial patterns along the latitudinal transect. This variability is not limited to the euphotic layer but also detectable in the meso- and bathypelagic layers. © 2016 The Authors. Environmental Microbiology Reports published by Society for Applied Microbiology and John Wiley & Sons Ltd.

ANALYSIS OF POLYMORPHISMS IN THE INTERLEUKIN 18 GENE PROMOTOR (-137 G/C AND -607 C/A) IN PATIENTS INFECTED WITH HEPATITIS C VIRUS FROM THE BRAZILIAN AMAZON.

PubMed

Santos, Kemper Nunes dos; Almeida, Marcella Kelly Costa de; Fecury, Amanda Alves; Costa, Carlos Araújo da; Martins, Luísa Caricio

2015-01-01

The hepatitis C virus has been recognized as the leading cause of chronic liver disease in the world. Host genetic factors have been implicated in the persistence of hepatitis C virus infection. Single nucleotide polymorphisms at positions -607 C/A (rs1946518) and -137 G/C (rs187238) in the IL-18 gene promoter have been suggested to be associated with delayed hepatitis C virus clearance and persistence of the disease. Identify these polymorphisms in a population infected with hepatitis C virus from the Brazilian Amazon region. In a cross-sectional analytical study conducted in Belém, Pará, Brazil, 304 patients infected with hepatitis C virus were divided into two groups: group A, patients with persistent infection; group B, patients with spontaneous clearance. The control group consisted of 376 volunteers not infected with hepatitis C virus. Samples were analyzed by RT-PCR for the detection of viral RNA and by RFLP-PCR to evaluate the presence of the -137 G/C and -607 C/A IL-18 gene promoter polymorphisms. Comparison of polymorphism allele frequencies between the patient and control groups showed a higher frequency of allele C at position -607 among patients (P=0.02). When the association between the polymorphisms and viral infection was analyzed, patients carrying genotype C/A at position -607 were found to be at higher risk of persistent hepatitis C virus infection (P=0.03). The present results suggest a possible role of the -607 IL-18 gene promoter polymorphism in the pathogenesis of hepatitis C virus infection.

Budesonide and Formoterol Reduce Early Innate Anti-Viral Immune Responses In Vitro

PubMed Central

Davies, Janet M.; Carroll, Melanie L.; Li, Hongzhuo; Poh, Alisa M.; Kirkegard, Darren; Towers, Michelle; Upham, John W.

2011-01-01

Asthma is a chronic inflammatory airways disease in which respiratory viral infections frequently trigger exacerbations. Current treatment of asthma with combinations of inhaled corticosteroids and long acting beta2 agonists improves asthma control and reduces exacerbations but what impact this might have on innate anti-viral immunity is unclear. We investigated the in vitro effects of asthma drugs on innate anti-viral immunity. Peripheral blood mononuclear cells (PBMC) from healthy and asthmatic donors were cultured for 24 hours with the Toll-like receptor 7 agonist, imiquimod, or rhinovirus 16 (RV16) in the presence of budesonide and/or formoterol. Production of proinflammatory cytokines and expression of anti-viral intracellular signalling molecules were measured by ELISA and RT-PCR respectively. In PBMC from healthy donors, budesonide alone inhibited IP-10 and IL-6 production induced by imiquimod in a concentration-dependent manner and the degree of inhibition was amplified when budesonide and formoterol were used in combination. Formoterol alone had little effect on these parameters, except at high concentrations (10−6 M) when IL-6 production increased. In RV16 stimulated PBMC, the combination of budesonide and formoterol inhibited IFNα and IP-10 production in asthmatic as well as healthy donors. Combination of budesonide and formoterol also inhibited RV16-stimulated expression of the type I IFN induced genes myxovirus protein A and 2′, 5′ oligoadenylate synthetise. Notably, RV16 stimulated lower levels of type Myxovirus A and oligoadenylate synthase in PBMC of asthmatics than control donors. These in vitro studies demonstrate that combinations of drugs commonly used in asthma therapy inhibit both early pro-inflammatory cytokines and key aspects of the type I IFN pathway. These findings suggest that budesonide and formoterol curtail excessive inflammation induced by rhinovirus infections in patients with asthma, but whether this inhibits viral clearance in vivo remains to be determined. PMID:22125636

Global Foot-and-Mouth Disease Research Update and Gap Analysis: 7 - Pathogenesis and Molecular Biology.

PubMed

Robinson, L; Knight-Jones, T J D; Charleston, B; Rodriguez, L L; Gay, C G; Sumption, K J; Vosloo, W

2016-06-01

We assessed research knowledge gaps in the fields of FMDV (foot-and-mouth disease virus) pathogenesis and molecular biology by performing a literature review (2011-15) and collecting research updates (2014) from 33 institutes from across the world. Findings were used to identify priority areas for future research. There have been important advances in FMDV pathogenesis; FMDV remains in lymph nodes of many recovered animals that otherwise do not appear persistently infected, even in species previously not associated with the carrier state. Whether virus retention helps maintain host immunity and/or virus survival is not known. Studies of FMDV pathogenesis in wildlife have provided insights into disease epidemiology, in endemic and epidemic settings. Many aspects of FMDV infection and virus entry remain unknown; however, at the cellular level, we know that expression level and availability of integrins (that permit viral entry), rate of clearance of infected cells and strength of anti-viral type I IFN (interferon) response are key determinants of tissue tropism. Extending findings to improved understanding of transmission requires a standardized approach and adoption of natural routes of infection during experimental study. There has been recognition of the importance of autophagosomes for FMDV entry into the cytoplasm following cell surface receptor binding, and that distinct internal cellular membranes are exploited for viral replication and immune evasion. New roles for viral proteins in blocking type I IFN production and downstream signalling have been identified facilitating research in anti-viral therapeutics. We know more about how infection affects cell protein expression, and research into molecular determinants of capsid stability has aided the development of stable vaccines. We have an expanding knowledge of viral and host molecular determinates of virulence and infectiousness, and of how phylogenetics may be used to estimate vaccine match and strain distribution. With ongoing advances, these areas could translate into significantly improved disease control. © 2016 Blackwell Verlag GmbH.

Patterns of amino acid conservation in human and animal immunodeficiency viruses.

PubMed

Voitenko, Olga S; Dhroso, Andi; Feldmann, Anna; Korkin, Dmitry; Kalinina, Olga V

2016-09-01

Due to their high genomic variability, RNA viruses and retroviruses present a unique opportunity for detailed study of molecular evolution. Lentiviruses, with HIV being a notable example, are one of the best studied viral groups: hundreds of thousands of sequences are available together with experimentally resolved three-dimensional structures for most viral proteins. In this work, we use these data to study specific patterns of evolution of the viral proteins, and their relationship to protein interactions and immunogenicity. We propose a method for identification of two types of surface residues clusters with abnormal conservation: extremely conserved and extremely variable clusters. We identify them on the surface of proteins from HIV and other animal immunodeficiency viruses. Both types of clusters are overrepresented on the interaction interfaces of viral proteins with other proteins, nucleic acids or low molecular-weight ligands, both in the viral particle and between the virus and its host. In the immunodeficiency viruses, the interaction interfaces are not more conserved than the corresponding proteins on an average, and we show that extremely conserved clusters coincide with protein-protein interaction hotspots, predicted as the residues with the largest energetic contribution to the interaction. Extremely variable clusters have been identified here for the first time. In the HIV-1 envelope protein gp120, they overlap with known antigenic sites. These antigenic sites also contain many residues from extremely conserved clusters, hence representing a unique interacting interface enriched both in extremely conserved and in extremely variable clusters of residues. This observation may have important implication for antiretroviral vaccine development. A Python package is available at https://bioinf.mpi-inf.mpg.de/publications/viral-ppi-pred/ voitenko@mpi-inf.mpg.de or kalinina@mpi-inf.mpg.de Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Disposition of pentachlorophenol in rainbow trout (Salmo gairdneri ): Effect of inhibition of metabolism

USGS Publications Warehouse

Stehly, G.R.; Hayton, W.L.

1989-01-01

The accumulation kinetics of pentachlorophenol (PCP) were investigated in rainbow trout (Salmo gairdneri ) in the absence and presence of 25 mg/l salicylamide, an inhibitor of PCP metabolism. After exposure to 5 mu g/l PCP over 1-96 h, the amount of PCP in the whole fish, its concentration in water and the total amount of metabolites (water, whole fish and bile) were measured. Equations for these variables, based on a two compartment pharmacokinetic model, were fitted simultaneously to the data using the computer program NONLIN, which uses an iterative nonlinear least squares technique. Salicylamide decreased the metabolic clearance of PCP, which resulted in an increase in the bioconcentration factor (BCF); this increase was partially offset by a salicylamide-induced decrease in the apparent volume of distribution of PCP. A clearance-volume compartment model permitted partitioning of the BCF in terms of the underlying physiologic and biochemical processes (uptake clearance, metabolic clearance and apparent volume of distribution).

Stereophysicochemical variability plots highlight conserved antigenic areas in Flaviviruses

PubMed Central

Schein, Catherine H; Zhou, Bin; Braun, Werner

2005-01-01

Background Flaviviruses, which include Dengue (DV) and West Nile (WN), mutate in response to immune system pressure. Identifying escape mutants, variant progeny that replicate in the presence of neutralizing antibodies, is a common way to identify functionally important residues of viral proteins. However, the mutations typically occur at variable positions on the viral surface that are not essential for viral replication. Methods are needed to determine the true targets of the neutralizing antibodies. Results Stereophysicochemical variability plots (SVPs), 3-D images of protein structures colored according to variability, as determined by our PCPMer program, were used to visualize residues conserved in their physical chemical properties (PCPs) near escape mutant positions. The analysis showed 1) that escape mutations in the flavivirus envelope protein are variable residues by our criteria and 2) two escape mutants found at the same position in many flaviviruses sit above clusters of conserved residues from different regions of the linear sequence. Conservation patterns in T-cell epitopes in the NS3- protease suggest a similar mechanism of immune system evasion. Conclusion The SVPs add another dimension to structurally defining the binding sites of neutralizing antibodies. They provide a useful aid for determining antigenically important regions and designing vaccines. PMID:15845145

Noncontact Capacitive Clearance Control System For Laser Cutting Machines

NASA Astrophysics Data System (ADS)

Topkaya, Ahmet; Schmall, Karl-Heinz; Majoli, Ralf

1989-03-01

For a continuous high quality laser cut, it is necessary among other things to position the focal point of the laser beam correctly. This means that a constant clearance between the cutting head and the workpiece with a tolerance of +/- 0.Imm must he ensured. When cutting corrugated automobile bodysheet for example, a good quality cut can only be achieved with automatic clearance control. In the following, a method of automatic clearance control is described using the assistance of a noncontact capacitive sensor system. The copper nozzle of the laser cutting head acts as the electrode of the clearance sensor. The nozzle electrode and the workpiece build a small variable capacitance depending on the clearance. A change of clearance also changes the capacitance, which in turn influences a high frequency oscillator circuit. This shift in frequency is then converted into an analogue DC signal, which can be used to operate a servo motor control for the positioning of the laser cutting head in a closed loop servo system. Laser cutting heads with clearance sensor nozzles of different shapes, suited fur most applications in the industry, with focal lengths from 2.5" to 5" have been developed. They are capable to cut metal sheet from 0.2 to 12 mm of thickness, using CO2-lasers with output power up to 2.5 kW. For special applications involving difficult workpiece topographies in automobile production applications special "trunk" nozzles have been developed. For 5-axis cutting machines and robots, new laser cutting heads with integrated nozzle sensors in combination with a high dynamic Z-axis motor drive are in a stage of development.

Viral Diseases in Zebrafish: What Is Known and Unknown

PubMed Central

Crim, Marcus J.; Riley, Lela K.

2013-01-01

Naturally occurring viral infections have the potential to introduce confounding variability that leads to invalid and misinterpreted data. Whereas the viral diseases of research rodents are well characterized and closely monitored, no naturally occurring viral infections have been characterized for the laboratory zebrafish (Danio rerio), an increasingly important biomedical research model. Despite the ignorance about naturally occurring zebrafish viruses, zebrafish models are rapidly expanding in areas of biomedical research where the confounding effects of unknown infectious agents present a serious concern. In addition, many zebrafish research colonies remain linked to the ornamental (pet) zebrafish trade, which can contribute to the introduction of new pathogens into research colonies, whereas mice used for research are purpose bred, with no introduction of new mice from the pet industry. Identification, characterization, and monitoring of naturally occurring viruses in zebrafish are crucial to the improvement of zebrafish health, the reduction of unwanted variability, and the continued development of the zebrafish as a model organism. This article addresses the importance of identifying and characterizing the viral diseases of zebrafish as the scope of zebrafish models expands into new research areas and also briefly addresses zebrafish susceptibility to experimental viral infection and the utility of the zebrafish as an infection and immunology model. PMID:23382345

Timing of dornase alfa inhalation for cystic fibrosis.

PubMed

Dentice, Ruth; Elkins, Mark

2016-07-26

Inhalation of the enzyme dornase alfa reduces sputum viscosity and improves clinical outcomes of people with cystic fibrosis. This is an update of a previously published Cochrane review. To determine the effect of timing of dornase alfa inhalation on measures of clinical efficacy in people with cystic fibrosis (in relation to airway clearance techniques or time of day). Relevant randomised and quasi-randomised controlled trials were identified from the Cochrane Cystic Fibrosis Trials Register, Physiotherapy Evidence Database (PEDro), and international cystic fibrosis conference proceedings.Date of the most recent search: 25 April 2016. Any trial of dornase alfa in people with cystic fibrosis where timing of inhalation was the randomised element in the study with either: inhalation before compared to after airway clearance techniques; or morning compared to evening inhalation. Both authors independently selected trials, assessed risk of bias and extracted data with disagreements resolved by discussion. Relevant data were extracted and, where possible, meta-analysed. We identified 115 trial reports representing 55 studies, of which five studies (providing data on 122 participants) met our inclusion criteria. All five studies used a cross-over design. Intervention periods ranged from two to eight weeks. Four trials compared dornase alfa inhalation before versus after airway clearance techniques. Inhalation after instead of before airway clearance did not significantly change forced expiratory volume at one second. Similarly, forced vital capacity and quality of life were not significantly affected; forced expiratory flow at 25% was significantly worse with dornase alfa inhalation after airway clearance, mean difference -0.17 litres (95% confidence interval -0.28 to -0.05), based on the pooled data from two small studies in children (seven to 19 years) with well-preserved lung function. All other secondary outcomes were statistically non-significant.In one trial, morning versus evening inhalation had no impact on lung function or symptoms. The current evidence derived from a small number of participants does not indicate that inhalation of dornase alfa after airway clearance techniques is more or less effective than the traditional recommendation to inhale nebulised dornase alfa 30 minutes prior to airway clearance techniques, for most outcomes. For children with well-preserved lung function, inhalation before airway clearance may be more beneficial for small airway function than inhalation after. However, this result relied on a measure with high variability and studies with variable follow up. In the absence of strong evidence to indicate that one timing regimen is better than another, the timing of dornase alpha inhalation can be largely based on pragmatic reasons or individual preference with respect to the time of airway clearance and time of day. Further research is warranted.

Stepping over obstacles: anticipatory modifications in children with and without Down syndrome.

PubMed

Virji-Babul, Naznin; Brown, Michelle

2004-12-01

The purpose of this study was to explore the mechanism of anticipatory control of gait in relation to the perception of an obstacle. Typically developing (TD) children (4-7 years of age) and children with Down syndrome (5-6 years of age) walked and stepped over obstacles of two different heights-a "subtle" obstacle that was placed at a very low distance from the floor (1% of total body height) and an "obvious" obstacle that was placed at a much higher distance from the floor (15% of total body height). Spatial and temporal measures of the gait cycle were analyzed. TD children showed increased variability in pre-obstacle step lengths only in response to the higher obstacle. Children with DS showed a decrease in variability in response to the higher obstacle and marked qualitative changes in their gait cycle. Both groups of children were able to scale toe clearance with obstacle height. These results show that TD young children can make task-specific anticipatory adjustments by modulating step length and toe clearance. Children with DS show appropriate scaling of toe clearance and are beginning to show the emergence of anticipatory responses under specific environmental conditions.

Soldier-relevant body borne load impacts minimum foot clearance during obstacle negotiation.

PubMed

Brown, T N; Loverro, K L; Schiffman, J M

2016-07-01

Soldiers often trip and fall on duty, resulting in injury. This study examined ten male soldiers' ability to negotiate an obstacle. Participants had lead and trail foot minimum foot clearance (MFC) parameters quantified while crossing a low (305 mm) and high (457 mm) obstacle with (19.4 kg) and without (6 kg) body borne load. To minimize tripping risk, participants increased lead foot MFC (p = 0.028) and reduced lead (p = 0.044) and trail (p = 0.035) foot variability when negotiating an obstacle with body borne load. While obstacle height had no effect on MFC (p = 0.273 and p = 0.126), placing the trail foot closer to the high obstacle when crossing with body borne load, resulted in greater lead (R = 0.640, b = 0.241, p = 0.046) and trail (R = 0.636, b = 0.287, p = 0.048) MFC. Soldiers, when carrying typical military loads, may be able to minimize their risk of tripping over an obstacle by creating a safety margin via greater foot clearance with reduced variability. Published by Elsevier Ltd.

Heart Rate Variability in Patients Being Treated for Dengue Viral Infection: New Insights from Mathematical Correction of Heart Rate

DTIC Science & Technology

2014-02-25

prognosis of viral infections, particu- larly in neonates and infants at risk of developing septic shock (Griffin and Moorman, 2001; Griffin et al...2004, 2005). In their studies, it was reported that abnormal HR with reduced variabil- ity and transient decelerations preceded neonatal /infant sepsis...hospital resuscitative treatment in DHF patients. After correction for prevailing HR, LF variability was still significantly increased (both P < 0.01) on day

Programmed cell death as a defence against infection

PubMed Central

Jorgensen, Ine; Rayamajhi, Manira; Miao, Edward A.

2017-01-01

Eukaryotic cells can die from physical trauma, resulting in necrosis. Alternately, they can die via programmed cell death upon stimulation of specific signalling pathways. Here we discuss the utility of four cell death pathways in innate immune defence against bacterial and viral infection: apoptosis, necroptosis, pyroptosis and NETosis. We describe the interactions that interweave different programmed cell death pathways, which create complex signalling networks that cross-guard each other in the evolutionary arms race with pathogens. Finally, we describe how the resulting cell corpses — apoptotic bodies, pore-induced intracellular traps (PITs) and neutrophil extracellular traps (NETs) — promote clearance of infection. PMID:28138137

Prognostic significance of blood lactate and lactate clearance in trauma patients.

PubMed

Régnier, Marie-Alix; Raux, Mathieu; Le Manach, Yannick; Asencio, Yves; Gaillard, Johann; Devilliers, Catherine; Langeron, Olivier; Riou, Bruno

2012-12-01

Lactate has been shown to be a prognostic biomarker in trauma. Although lactate clearance has already been proposed as an intermediate endpoint in randomized trials, its precise role in trauma patients remains to be determined. Blood lactate levels and lactate clearance (LC) were calculated at admission and 2 and 4 h later in trauma patients. The association of initial blood lactate level and lactate clearance with mortality was tested using receiver-operating characteristics curve, logistic regression using triage scores, Trauma Related Injury Severity Score as a reference standard, and reclassification method. The authors evaluated 586 trauma patients (mean age 38±16 yr, 84% blunt and 16% penetrating, mortality 13%). Blood lactate levels at admission were elevated in 327 (56%) patients. The lactate clearance should be calculated within the first 2 h after admission as LC0-2 h was correlated with LC0-4 h (R=0.55, P<0.001) but not with LC2-4 h (R=0.04, not significant). The lactate clearance provides additional predictive information to initial blood lactate levels and triage scores and the reference score. This additional information may be summarized using a categorical approach (i.e., less than or equal to -20 %/h) in contrast to initial blood lactate. The results were comparable in patients with high (5 mM/l or more) initial blood lactate. Early (0-2 h) lactate clearance is an important and independent prognostic variable that should probably be incorporated in future decision schemes for the resuscitation of trauma patients.

Effects of shoe sole geometry on toe clearance and walking stability in older adults.

PubMed

Thies, S B; Price, C; Kenney, L P J; Baker, R

2015-07-01

Thirty-five percent of people above age 65 fall each year, and half of their falls are associated with tripping: tripping, an apparently 'mundane' everyday problem, therefore, significantly impacts on older people's health and associated medical costs. To avoid tripping and subsequent falling, sufficient toe clearance during the swing phase is crucial. We previously found that a rocker-shaped shoe sole enhances toe clearance in young adults, thereby decreasing their trip-risk. This study investigates whether such sole design also enhances older adults' toe clearance, without inadvertently affecting their walking stability. Toe clearance and its variability are reported together with measures of walking stability for twelve older adults, walking in shoes with rocker angles of 10°, 15°, and 20°. Surface inclinations (flat, incline, decline) were chosen to reflect a potential real-world environment. Toe clearance increased substantially from the 10° to the 15° rocker angle (p=0.003) without compromising measures of walking stability (p>0.05). A further increase in rocker angle to 20° resulted in less substantial enhancement of toe clearance and came at the cost of a decrease in gait speed on the decline. The novelty of this investigation lies in the exploration of the trade-off between reduction of trip-risk through footwear design and adverse effects on walking stability on real-life relevant surfaces. Our two studies suggest that the current focus on slip-resistance in footwear design may need to be generalised to include other factors that affect trip-risk. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Experimental study of uncentralized squeeze film dampers

NASA Technical Reports Server (NTRS)

Quinn, R. D.

1983-01-01

The vibration response of a rotor system supported by a squeeze film damper (SFD) was experimentally investigated in order to provide experimental data in support of the Rotor/Stator Interactive Finite Element theoretical development. Part of the investigation required the designing and building of a rotor/SFD system that could operate with or without end seals in order to accommodate different SFD lengths. SFD variables investigated included clearance, eccentricity mass, fluid pressure, and viscosity and temperature. The results show inlet pressure, viscosity and clearance have significant influence on the damper performance and accompanying rotor response.

Low-coherence interferometric tip-clearance probe

NASA Astrophysics Data System (ADS)

Kempe, Andreas; Schlamp, Stefan; Rösgen, Thomas; Haffner, Ken

2003-08-01

We propose an all-fiber, self-calibrating, economical probe that is capable of near-real-time, single-port, simultaneous blade-to-blade tip-clearance measurements with submillimeter accuracy (typically <100 μm, absolute) in the first stages of a gas turbine. Our probe relies on the interference between backreflected light from the blade tips during the 1-μs blade passage time and a frequency-shifted reference with variable time delay, making use of a low-coherence light source. A single optical fiber of arbitrary length connects the self-contained optics and electronics to the turbine.

IFN-λ Inhibits MiR-122 Transcription through a Stat3-HNF4α Inflammatory Feedback Loop in an IFN-α Resistant HCV Cell Culture System

PubMed Central

Aboulnasr, Fatma; Hazari, Sidhartha; Nayak, Satyam; Chandra, Partha K.; Panigrahi, Rajesh; Ferraris, Pauline; Chava, Srinivas; Kurt, Ramazan; Song, Kyongsub; Dash, Asha; Balart, Luis A.; Garry, Robert F.; Wu, Tong; Dash, Srikanta

2015-01-01

Background HCV replication in persistently infected cell culture remains resistant to IFN-α/RBV combination treatment, whereas IFN-λ1 induces viral clearance. The antiviral mechanisms by which IFN-λ1 induces sustained HCV clearance have not been determined. Aim To investigate the mechanisms by which IFN-λ clears HCV replication in an HCV cell culture model. Methods IFN-α sensitive (S3-GFP) and resistant (R4-GFP) cells were treated with equivalent concentrations of either IFN-α or IFN-λ. The relative antiviral effects of IFN-α and IFN-λ1 were compared by measuring the HCV replication, quantification of HCV-GFP expression by flow cytometry, and viral RNA levels by real time RT-PCR. Activation of Jak-Stat signaling, interferon stimulated gene (ISG) expression, and miRNA-122 transcription in S3-GFP and R4-GFP cells were examined. Results We have shown that IFN-λ1 induces HCV clearance in IFN-α resistant and sensitive replicon cell lines in a dose dependent manner through Jak-Stat signaling, and induces STAT 1 and STAT 2 activation, ISRE-luciferase promoter activation and ISG expression. Stat 3 activation is also involved in IFN-λ1 induced antiviral activity in HCV cell culture. IFN-λ1 induced Stat 3 phosphorylation reduces the expression of hepatocyte nuclear factor 4 alpha (HNF4α) through miR-24 in R4-GFP cells. Reduced expression of HNF4α is associated with decreased expression of miR-122 resulting in an anti-HCV effect. Northern blot analysis confirms that IFN-λ1 reduces miR-122 levels in R4-GFP cells. Our results indicate that IFN-λ1 activates the Stat 3-HNF4α feedback inflammatory loop to inhibit miR-122 transcription in HCV cell culture. Conclusions In addition to the classical Jak–Stat antiviral signaling pathway, IFN-λ1 inhibits HCV replication through the suppression of miRNA-122 transcription via an inflammatory Stat 3–HNF4α feedback loop. Inflammatory feedback circuits activated by IFNs during chronic inflammation expose non-responders to the risk of hepatocellular carcinoma. PMID:26657215

Quantitative assessment of the contribution of sodium-dependent taurocholate co-transporting polypeptide (NTCP) to the hepatic uptake of rosuvastatin, pitavastatin and fluvastatin.

PubMed

Bi, Yi-an; Qiu, Xi; Rotter, Charles J; Kimoto, Emi; Piotrowski, Mary; Varma, Manthena V; Ei-Kattan, Ayman F; Lai, Yurong

2013-11-01

Hepatic uptake transport is often the rate-determining step in the systemic clearance of drugs. The ability to predict uptake clearance and to determine the contribution of individual transporters to overall hepatic uptake is therefore critical in assessing the potential pharmacokinetic and pharmacodynamic variability associated with drug-drug interactions and pharmacogenetics. The present study revisited the interaction of statin drugs, including pitavastatin, fluvastatin and rosuvastatin, with the sodium-dependent taurocholate co-transporting polypeptide (NTCP) using gene transfected cell models. In addition, the uptake clearance and the contribution of NTCP to the overall hepatic uptake were assessed using in vitro hepatocyte models. Then NTCP protein expression was measured by a targeted proteomics transporter quantification method to confirm the presence and stability of NTCP expression in suspended and cultured hepatocyte models. It was concluded that NTCP-mediated uptake contributed significantly to active hepatic uptake in hepatocyte models for all three statins. However, the contribution of NTCP-mediated uptake to the overall active hepatic uptake was compound-dependent and varied from about 24% to 45%. Understanding the contribution of individual transporter proteins to the overall hepatic uptake and its functional variability when other active hepatic uptake pathways are interrupted could improve the current prediction practice used to assess the pharmacokinetic variability due to drug-drug interactions, pharmacogenetics and physiopathological conditions in humans. Copyright © 2013 John Wiley & Sons, Ltd.

Population pharmacokinetics of theophylline in adult Chinese patients with asthma and chronic obstructive pulmonary disease.

PubMed

Ma, Yanjiao; Xue, Ling; Chen, Xin; Kang, Yingbo; Wang, Yong; Wang, Liqing

2018-05-18

Background Theophylline has a narrow therapeutic range and large interindividual variability in blood levels, so a thorough understanding of its pharmacokinetic characteristics is essential. Population pharmacokinetic (PPK) approaches could achieve it and many PPK studies of theophylline have been reported in infants. However, none was conducted in Chinese adults and none has explored the effect of CYP1A2 genotypes on the PPK characteristics of theophylline in adults. Objective To evaluate the PPK characteristics of theophylline and to assess the possible influence of covariates, including CYP1A2 genotypes, on theophylline clearance in Chinese adult patients. Setting The study is conducted at the department of respiration in Zhujiang Hospital, Guangzhou, China. Methods Theophylline concentrations were obtained from eligible patients and were measured by high performance liquid chromatography. The polymorphisms of - 3860G > A, - 163C > A, C5347T (CYP1A2*1B) and G-3113A were genotyped using a direct sequencing method. Then, CYP1A2 genotypes, age, fat-free mass (FFM) and other covariates were used to develop a PPK model by NONMEM software. Bootstrap analysis was used to asses the accuracy and prediction of the PPK model. Main outcome measure The concentration and clearance of theophylline. Results A total of 134 theophylline concentrations from 95 patients were obtained. The final model was as follows: CL/F(L/h) = 4.530 × (FFM/56.1) 0.75  × 0.713 CYP1A2*1B , the inter-individual variability in clearance/bioavailability (CL/F) was 44.0%, and the residual variability was 9.8%. The final model was proved to be reliable by bootstrap analysis. Conclusion Theophylline clearance was significantly associated with FFM and CYP1A2*1B genotypes in Chinese adult patients.

Association between HIV replication and serum leptin levels: an observational study of a cohort of HIV-1-infected South African women

PubMed Central

2010-01-01

Background Advanced HIV infection can result in lipoatrophy and wasting, even in the absence of ongoing opportunistic infections, suggesting that HIV may directly affect adipose tissue amount and distribution. Methods We assessed the relationship of fat (measured using anthropometry, DEXA, MRI scans) or markers related to glucose and lipid metabolism with viral load in a cross-sectional sample of 83 antiretroviral-naïve HIV-1-infected South African women. A multivariable linear model was fitted to log10VL to assess the combined effect of these variables. Results In addition to higher T cell activation, women with viral load greater than the population median had lower waist circumference, body mass index and subcutaneous abdominal fat, as well as lower serum leptin. We demonstrate that leptin serum levels are inversely associated with viral replication, independent of the amount of adipose tissue. This association is maintained after adjusting for multiple variables associated with disease progression (i.e., cellular activation and innate immunity effector levels). Conclusions Our results demonstrate that serum leptin levels are inversely associated with viral replication, independent of disease progression: we postulate that leptin may affect viral replication. PMID:20822522

Enhanced model of gear transmission dynamics for condition monitoring applications: Effects of torque, friction and bearing clearance

NASA Astrophysics Data System (ADS)

Fernandez-del-Rincon, A.; Garcia, P.; Diez-Ibarbia, A.; de-Juan, A.; Iglesias, M.; Viadero, F.

2017-02-01

Gear transmissions remain as one of the most complex mechanical systems from the point of view of noise and vibration behavior. Research on gear modeling leading to the obtaining of models capable of accurately reproduce the dynamic behavior of real gear transmissions has spread out the last decades. Most of these models, although useful for design stages, often include simplifications that impede their application for condition monitoring purposes. Trying to filling this gap, the model presented in this paper allows us to simulate gear transmission dynamics including most of these features usually neglected by the state of the art models. This work presents a model capable of considering simultaneously the internal excitations due to the variable meshing stiffness (including the coupling among successive tooth pairs in contact, the non-linearity linked with the contacts between surfaces and the dissipative effects), and those excitations consequence of the bearing variable compliance (including clearances or pre-loads). The model can also simulate gear dynamics in a realistic torque dependent scenario. The proposed model combines a hybrid formulation for calculation of meshing forces with a non-linear variable compliance approach for bearings. Meshing forces are obtained by means of a double approach which combines numerical and analytical aspects. The methodology used provides a detailed description of the meshing forces, allowing their calculation even when gear center distance is modified due to shaft and bearing flexibilities, which are unavoidable in real transmissions. On the other hand, forces at bearing level were obtained considering a variable number of supporting rolling elements, depending on the applied load and clearances. Both formulations have been developed and applied to the simulation of the vibration of a sample transmission, focusing the attention on the transmitted load, friction meshing forces and bearing preloads.

Relationship between dietary protein intake and the changes in creatinine clearance and glomerular cross-sectional area in patients with IgA nephropathy.

PubMed

Wada, Toshikazu; Nakao, Toshiyuki; Matsumoto, Hiroshi; Okada, Tomonari; Nagaoka, Yume; Iwasawa, Hideaki; Gondo, Asako; Niwata, Ami; Kanno, Yoshihiko

2015-08-01

Dietary protein intake (PI) induces glomerular hyperfiltration and reduced dietary PI can be effective in preserving kidney function. However, there is limited information regarding the relationship between dietary PI and glomerular histological changes in chronic kidney disease. We investigated the relationship between changes in dietary PI and both the changes in creatinine clearance and glomerular histomorphometry in adult patients with IgA nephropathy (IgAN). A total of 24 consecutive adult patients with biopsy-confirmed IgAN were enrolled and glomerular histomorphometric variables and clinical variables were investigated. The main clinical variables were differences in creatinine clearance (Ccr) (dCcr) and in PI (dPI) which were calculated by subtracting PI and Ccr values in patients on a controlled diet during hospitalization for kidney biopsy from the respective values in patients on daily diets as outpatients. These values of PI were estimated from urinary urea excretion measured by 24-h urine collection. The main renal histomorphometric variable was glomerular tuft area (GTA) (μm(2)). dCcr positively correlated with dPI (r = 0.726, P < 0.001). GTA correlated positively with dPI (r = 0.556, P = 0.013). Multiple regression analysis showed that dPI was independently associated with both dCcr and GTA. Additionally, GTA positively correlated with dietary PI as outpatients (r = 0.457, P = 0.043). Changes in dietary PI were associated with the changes in glomerular filtration rate. Furthermore, histomorphometric findings suggested that a greater dietary PI can affect the glomerular size at the time of the initial diagnostic biopsy for IgAN.

Creatinine Clearance Is Not Equal to Glomerular Filtration Rate and Cockcroft-Gault Equation Is Not Equal to CKD-EPI Collaboration Equation.

PubMed

Fernandez-Prado, Raul; Castillo-Rodriguez, Esmeralda; Velez-Arribas, Fernando Javier; Gracia-Iguacel, Carolina; Ortiz, Alberto

2016-12-01

Direct oral anticoagulants (DOACs) may require dose reduction or avoidance when glomerular filtration rate is low. However, glomerular filtration rate is not usually measured in routine clinical practice. Rather, equations that incorporate different variables use serum creatinine to estimate either creatinine clearance in mL/min or glomerular filtration rate in mL/min/1.73 m 2 . The Cockcroft-Gault equation estimates creatinine clearance and incorporates weight into the equation. By contrast, the Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations estimate glomerular filtration rate and incorporate ethnicity but not weight. As a result, an individual patient may have very different renal function estimates, depending on the equation used. We now highlight these differences and discuss the impact on routine clinical care for anticoagulation to prevent embolization in atrial fibrillation. Pivotal DOAC clinical trials used creatinine clearance as a criterion for patient enrollment, and dose adjustment and Federal Drug Administration recommendations are based on creatinine clearance. However, clinical biochemistry laboratories provide CKD-EPI glomerular filtration rate estimations, resulting in discrepancies between clinical trial and routine use of the drugs. Copyright © 2016 Elsevier Inc. All rights reserved.

The detailed measurement of foot clearance by young adults during stair descent.

PubMed

Telonio, A; Blanchet, S; Maganaris, C N; Baltzopoulos, V; McFadyen, B J

2013-04-26

Foot clearance is an important variable for understanding safe stair negotiation, but few studies have provided detailed measures of it. This paper presents a new method to calculate minimal shoe clearance during stair descent and compares it to previous literature. Seventeen healthy young subjects descended a five step staircase with step treads of 300 mm and step heights of 188 mm. Kinematic data were collected with an Optotrak system (model 3020) and three non-colinear infrared markers on the feet. Ninety points were digitized on the foot sole prior to data collection using a 6 marker probe and related to the triad of markers on the foot. The foot sole was reconstructed using the Matlab (version 7.0) "meshgrid" function and minimal distance to each step edge was calculated for the heel, toe and foot sole. Results showed significant differences in minimum clearance between sole, heel and toe, with the shoe sole being the closest and the toe the furthest. While the hind foot sole was closest for 69% of the time, the actual minimum clearance point on the sole did vary across subjects and staircase steps. This new method, and the findings on healthy young subjects, can be applied to future studies of other populations and staircase dimensions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Progress on Shape Memory Alloy Actuator Development for Active Clearance Control

NASA Technical Reports Server (NTRS)

DeCastro, Jonathan; Melcher, Kevin; Noebe, Ronald

2006-01-01

Results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine has been conducted. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 in. Design results show that an actuator comprised of 10 wires 2 in. in length is adequate for control at critical engine operating points and still exhibit acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

Interaction of extremophilic archaeal viruses with human and mouse complement system and viral biodistribution in mice

PubMed Central

Wu, Linping; Uldahl, Kristine Buch; Chen, Fangfang; Benasutti, Halli; Logvinski, Deborah; Vu, Vivian; Banda, Nirmal K.; Peng, Xu; Simberg, Dmitri; Moghimi, Seyed Moein

2017-01-01

Archaeal viruses offer exceptional biophysical properties for modification and exploration of their potential in bionanotechnology, bioengineering and nanotherapeutic developments. However, the interaction of archaeal viruses with elements of the innate immune system has not been explored, which is a necessary prerequisite if their potential for biomedical applications to be realized. Here we show complement activation through lectin (via direct binding of MBL/MASPs) and alternative pathways by two extremophilic archaeal viruses (Sulfolobus monocaudavirus 1 and Sulfolobus spindle-shaped virus 2) in human serum. We further show some differences in initiation of complement activation pathways between these viruses. Since, Sulfolobus monocaudavirus 1 was capable of directly triggering the alternative pathway, we also demonstrate that the complement regulator factor H has no affinity for the viral surface, but factor H deposition is purely C3-dependent. This suggests that unlike some virulent pathogens Sulfolobus monocaudavirus 1 does not acquire factor H for protection. Complement activation with Sulfolobus monocaudavirus 1 also proceeds in murine sera through MBL-A/C as well as factor D-dependent manner, but C3 deficiency has no overall effect on viral clearance by organs of the reticuloendothelial system on intravenous injection. However, splenic deposition was significantly higher in C3 knockout animals compared with the corresponding wild type mice. We discuss the potential application of these viruses in biomedicine in relation to their complement activating properties. PMID:28846925

Cervicovaginal secretions protect from human papillomavirus infection: effects of vaginal douching.

PubMed

Chu, Tang-Yuan; Chang, Ying-Cheng; Ding, Dah-Ching

2013-06-01

Cervicovaginal secretions (CVSs) are reported to protect against human papillomavirus (HPV) infection. Although vaginal douching is known to clear both viral inoculants and CVSs, its effect on CVSs in women with HPV infection is unknown. The in vitro HPV pseudovirus infection system was used to test the protective activity of CVSs against HPV infection in samples collected before and after vaginal douching. To simulate different time points of vaginal douching in relation to viral exposure, the cell CVS reconstitute was washed after different viral exposure durations. In the CVSs of premenopausal and postmenopausal women who did not perform douching, the CVSs inhibited HPV infection by 56.7 ± 1.8% and 53.6 ± 2.5%, respectively; in women who had performed douching, the CVSs inhibited HPV infection by only 31.2 ± 7.1%, which was significantly lower (p < 0.01). Cell washing effectively cleared 60-90% of the infectious load with the greatest activity occurring within 30 minutes after inoculation. In the presence of CVSs, a sustained inhibition of HPV infection existed for up to 8 hours after HPV exposure, and cell washing increased the clearance to up to 82-93% of the infectious load. This study confirms the protective activity of CVSs against HPV infection regardless of age. In this in vitro study, the net effect of douching was found to be beneficial. Copyright © 2013. Published by Elsevier B.V.

A comparative study of pulsed dye laser versus long pulsed Nd:YAG laser treatment in recalcitrant viral warts.

PubMed

Shin, Yo Sup; Cho, Eun Byul; Park, Eun Joo; Kim, Kwang Ho; Kim, Kwang Joong

2017-08-01

Viral warts are common infectious skin disease induced by human papillomavirus (HPV). But the treatment of recalcitrant warts is still challenging. In this study, we compared the effectiveness of pulsed dye laser (PDL) and long pulsed Nd:YAG (LPNY) laser in the treatment of recalcitrant viral warts. We retrospectively analyzed the medical records of patients with recalcitrant warts treated with laser therapy between January 2013 and February 2016. Seventy-two patients with recalcitrant warts were evaluated. Thirty-nine patients were treated with pulsed dye laser and thirty-three patients were treated with LPNY laser. The following parameters were used: PDL (spot size, 7 mm; pulse duration, 1.5 ms; and fluence, 10-14 J/cm 2 ) and LPNY (spot size, 5 mm; pulse duration, 20 ms; and fluence, 240-300 J/cm 2 ). Complete clearance of two patients (5.1%) in PDL group, and three patients (9.1%) in LPNY group were observed without significant side effects. The patients who achieved at least 50% improvement from baseline were 20 (51.3%) in PDL and 22 (66.7%) in LPNY, respectively. This research is meaningful because we compared the effectiveness of the PDL and LPNY in the recalcitrant warts. Both PDL and LPNY laser could be used as a safe and alternative treatment for recalcitrant warts.

Structural and Nonstructural Viral Proteins Are Targets of T-Helper Immune Response against Human Respiratory Syncytial Virus.

PubMed

Lorente, Elena; Barriga, Alejandro; Barnea, Eilon; Mir, Carmen; Gebe, John A; Admon, Arie; López, Daniel

2016-06-01

Proper antiviral humoral and cellular immune responses require previous recognition of viral antigenic peptides that are bound to HLA class II molecules, which are exposed on the surface of antigen-presenting cells. The helper immune response is critical for the control and the clearance of human respiratory syncytial virus (HRSV) infection, a virus with severe health risk in infected pediatric, immunocompromised, and elderly populations. In this study, using a mass spectrometry analysis of complex HLA class II-bound peptide pools that were isolated from large amounts of HRSV-infected cells, 19 naturally processed HLA-DR ligands, most of them included in a complex nested set of peptides, were identified. Both the immunoprevalence and the immunodominance of the HLA class II response to HRSV were focused on one nonstructural (NS1) and two structural (matrix and mainly fusion) proteins of the infective virus. These findings have clear implications for analysis of the helper immune response as well as for antiviral vaccine design. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Ethanol affects hepatitis C pathogenesis: humanized SCID Alb-uPA mouse model.

PubMed

Osna, Natalia A; Kharbanda, Kusum K; Sun, Yimin; Simpson, Ronda L; Poluektova, Larisa E; Ganesan, Murali; Wisecarver, James L; Mercer, David F

2014-07-18

Alcohol consumption exacerbates the course of hepatitis C viral (HCV) infection, worsens outcomes and contributes to the development of chronic infection that exhibits low anti-viral treatment efficiency. The lack of suitable in vivo models makes HCV-ethanol studies very difficult. Here, we examine whether chimeric SCID Alb-uPA mice transplanted with human hepatocytes and infected with HCV develop worsening pathology when fed ethanol. After 5 weeks of feeding, such mice fed chow+water (control) or chow+20% ethanol in water (EtOH) diets mice developed oxidative stress, decreased proteasome activity and increased steatosis. Importantly, HCV(+) mice in the control group cleared HCV RNA after 5 weeks, while the infection persisted in EtOH-fed mice at the same or even higher levels compared with pre-feeding HCV RNA. We conclude that in chimeric SCID Alb-uPA mice, EtOH exposure causes the complex biochemical and histological changes typical for alcoholic liver injury. In addition, ethanol feeding delays the clearance of HCV RNA thereby generating persistent infection and promoting liver injury. Overall, this model is appropriate for conducting HCV-ethanol studies. Published by Elsevier Inc.

Natural variants of cytotoxic epitopes are T-cell receptor antagonists for antiviral cytotoxic T cells

NASA Astrophysics Data System (ADS)

Bertoletti, Antonio; Sette, Alessandro; Chisari, Francis V.; Penna, Amalia; Levrero, Massimo; Carli, Marco De; Fiaccadori, Franco; Ferrari, Carlo

1994-06-01

IT has been suggested that mutations within immunodominant cytotoxic T-lymphocyte (CTL) epitopes may be exploited by viruses to evade protective immune responses critical for clearance1-4. Viral escape could originate from passive mechanisms, such as mutations within crucial CTL epitopes, either affecting major histocompatibility complex binding or T-cell antigen receptor (TCR) recognition. Additionally, it has recently been shown that substitutions of TCR contact sites can yield analogue peptides that can still interact with the T-cell receptor but be unable to deliver a full stimulatory signal, thus inducing anergy5 or acting as an antagonist for the TCR6-8. We report here that hepatitis B virus isolates derived from two chronically infected patients display variant epitopes that act as natural TCR antagonists with the capacity to inhibit the CTL response to the wild-type epitope. During natural infection, TCR antagonist mutations of CTL epitopes could contribute to the development of viral persistence, especially if the antiviral CTL response is monospecific or the epitope is strongly immunodominant.

Viruses are prevalent in non-ventilated hospital-acquired pneumonia.

PubMed

Shorr, Andrew F; Zilberberg, Marya D; Micek, Scott T; Kollef, Marin H

2017-01-01

Hospital-acquired pneumonia arising in non-ventilated patients (NVHAP) is traditionally thought to be caused by bacteria, and little is known about viral etiologies in this syndrome. We sought to describe the prevalence of viruses causing NVHAP and to determine factors independently associated with the isolation of a virus. We identified patients with NVHAP over one year and reviewed their cultures to determine etiologies. Patients with a viral process were compared to those with either negative cultures or a bacterial infection to determine variables independently associated with the recovery of a virus. Among 174 cases, cultures were positive in 46.0%, with viruses identified in 22.4%. Bacterial pathogens arose 23.6% of subjects. The most common viruses included rhinovirus, influenza, and parainfluenza. We noted no seasonality in the isolation of viral organisms, and most cases of viral NVHAP developed after more than a week length of stay (LOS). Outcomes in viral NVHAP were similar to those with bacterial NVHAP. Patients with viral and bacterial NVHAP were generally similar. Two variables were independently associated with isolation of a virus: a history of coronary artery disease (adjusted odds ratio: 5.16, 95% CI: 1.14-22.44) and a LOS of greater than 10 days prior to NVHAP diagnosis (adjusted odds ratio: 2.97, 95% CI: 1.35-6.51). As a screening test for a virus, neither had a good sensitivity or specificity. Viruses represent a common cause of NVHAP. Clinicians should consider viral diagnostic testing in NVHAP, as this may represent a means to enhance antimicrobial stewardship. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantitative Evaluation of Protein Heterogeneity within Herpes Simplex Virus 1 Particles.

PubMed

El Bilali, Nabil; Duron, Johanne; Gingras, Diane; Lippé, Roger

2017-05-15

Several virulence genes have been identified thus far in the herpes simplex virus 1 genome. It is also generally accepted that protein heterogeneity among virions further impacts viral fitness. However, linking this variability directly with infectivity has been challenging at the individual viral particle level. To address this issue, we resorted to flow cytometry (flow virometry), a powerful approach we recently employed to analyze individual viral particles, to identify which tegument proteins vary and directly address if such variability is biologically relevant. We found that the stoichiometry of the U L 37, ICP0, and VP11/12 tegument proteins in virions is more stable than the VP16 and VP22 tegument proteins, which varied significantly among viral particles. Most interestingly, viruses sorted for their high VP16 or VP22 content yielded modest but reproducible increases in infectivity compared to their corresponding counterparts containing low VP16 or VP22 content. These findings were corroborated for VP16 in short interfering RNA experiments but proved intriguingly more complex for VP22. An analysis by quantitative Western blotting revealed substantial alterations of virion composition upon manipulation of individual tegument proteins and suggests that VP22 protein levels acted indirectly on viral fitness. These findings reaffirm the interdependence of the virion components and corroborate that viral fitness is influenced not only by the genome of viruses but also by the stoichiometry of proteins within each virion. IMPORTANCE The ability of viruses to spread in animals has been mapped to several viral genes, but other factors are clearly involved, including virion heterogeneity. To directly probe whether the latter influences viral fitness, we analyzed the protein content of individual herpes simplex virus 1 particles using an innovative flow cytometry approach. The data confirm that some viral proteins are incorporated in more controlled amounts, while others vary substantially. Interestingly, this correlates with the VP16 trans -activating viral protein and indirectly with VP22, a second virion component whose modulation profoundly alters virion composition. This reaffirms that not only the presence but also the amount of specific tegument proteins is an important determinant of viral fitness. Copyright © 2017 American Society for Microbiology.

Quantitative Evaluation of Protein Heterogeneity within Herpes Simplex Virus 1 Particles

PubMed Central

El Bilali, Nabil; Duron, Johanne; Gingras, Diane

2017-01-01

ABSTRACT Several virulence genes have been identified thus far in the herpes simplex virus 1 genome. It is also generally accepted that protein heterogeneity among virions further impacts viral fitness. However, linking this variability directly with infectivity has been challenging at the individual viral particle level. To address this issue, we resorted to flow cytometry (flow virometry), a powerful approach we recently employed to analyze individual viral particles, to identify which tegument proteins vary and directly address if such variability is biologically relevant. We found that the stoichiometry of the UL37, ICP0, and VP11/12 tegument proteins in virions is more stable than the VP16 and VP22 tegument proteins, which varied significantly among viral particles. Most interestingly, viruses sorted for their high VP16 or VP22 content yielded modest but reproducible increases in infectivity compared to their corresponding counterparts containing low VP16 or VP22 content. These findings were corroborated for VP16 in short interfering RNA experiments but proved intriguingly more complex for VP22. An analysis by quantitative Western blotting revealed substantial alterations of virion composition upon manipulation of individual tegument proteins and suggests that VP22 protein levels acted indirectly on viral fitness. These findings reaffirm the interdependence of the virion components and corroborate that viral fitness is influenced not only by the genome of viruses but also by the stoichiometry of proteins within each virion. IMPORTANCE The ability of viruses to spread in animals has been mapped to several viral genes, but other factors are clearly involved, including virion heterogeneity. To directly probe whether the latter influences viral fitness, we analyzed the protein content of individual herpes simplex virus 1 particles using an innovative flow cytometry approach. The data confirm that some viral proteins are incorporated in more controlled amounts, while others vary substantially. Interestingly, this correlates with the VP16 trans-activating viral protein and indirectly with VP22, a second virion component whose modulation profoundly alters virion composition. This reaffirms that not only the presence but also the amount of specific tegument proteins is an important determinant of viral fitness. PMID:28275191

Voltammetric and Mathematical Evidence for Dual Transport Mediation of Serotonin Clearance In Vivo

PubMed Central

Wood, Kevin M.; Zeqja, Anisa; Nijhout, H. Frederik; Reed, Michael C.; Best, Janet; Hashemi, Parastoo

2014-01-01

The neurotransmitter serotonin underlies many of the brain’s functions. Understanding serotonin neurochemistry is important for improving treatments for neuropsychiatric disorders such as depression. Antidepressants commonly target serotonin clearance via serotonin transporters (SERTs) and have variable clinical effects. Adjunctive therapies, targeting other systems including serotonin autoreceptors, also vary clinically and carry adverse consequences. Fast scan cyclic voltammetry (FSCV) is particularly well suited for studying antidepressant effects on serotonin clearance and autoreceptors by providing real-time chemical information on serotonin kinetics in vivo. However, the complex nature of in vivo serotonin responses makes it difficult to interpret experimental data with established kinetic models. Here, we electrically stimulated the mouse medial forebrain bundle (MFB) to provoke and detect terminal serotonin in the substantia nigra reticulata (SNr). In response to MFB stimulation we found three dynamically distinct serotonin signals. To interpret these signals we developed a computational model that supports two independent serotonin reuptake mechanisms (high affinity, low efficiency reuptake mechanism and low affinity, high efficiency reuptake system) and bolsters an important inhibitory role for the serotonin autoreceptors. Our data and analysis, afforded by the powerful combination of voltammetric and theoretical methods, gives new understanding of the chemical heterogeneity of serotonin dynamics in the brain. This diverse serotonergic matrix likely contributes to clinical variability of antidepressants. PMID:24702305

Genetic ablation of arginase 1 in macrophages and neutrophils enhances clearance of an arthritogenic alphavirus

PubMed Central

Stoermer, Kristina A.; Burrack, Adam; Oko, Lauren; Montgomery, Stephanie A.; Borst, Luke B.; Gill, Ronald G.; Morrison, Thomas E.

2012-01-01

Chikungunya virus (CHIKV) and Ross River virus (RRV) cause a debilitating, and often chronic, musculoskeletal inflammatory disease in humans. Macrophages constitute the major inflammatory infiltrates in musculoskeletal tissues during these infections. However, the precise macrophage effector functions that affect the pathogenesis of arthritogenic alphaviruses have not been defined. We hypothesized that the severe damage to musculoskeletal tissues observed in RRV or CHIKV-infected mice would promote a wound healing response characterized by M2-like macrophages. Indeed, we found that RRV and CHIKV-induced musculoskeletal inflammatory lesions, and macrophages present in these lesions, have a unique gene expression pattern characterized by high expression of arginase 1 and Ym1/Chi3l3 in the absence of FIZZ1/Relmα that is consistent with an M2-like activation phenotype. Strikingly, mice specifically deleted for Arg1 in neutrophils and macrophages had dramatically reduced viral loads and improved pathology in musculoskeletal tissues at late times post-RRV infection. These findings indicate that arthritogenic alphavirus infection drives a unique myeloid cell activation program in inflamed musculoskeletal tissues that inhibits virus clearance and impedes disease resolution in an Arg1-dependent manner. PMID:22972923

Virology, Immunology and Pathology of Human Rabies During Treatment

PubMed Central

Caicedo, Yolanda; Paez, Andres; Kuzmin, Ivan; Niezgoda, Michael; Orciari, Lillian A.; Yager, Pamela A.; Recuenco, Sergio; Franka, Richard; Velasco-Villa, Andres; Willoughby, Rodney E.

2016-01-01

Background Rabies is an acute fatal encephalitis caused by all members of the Lyssavirus genus. The first human rabies survivor without benefit of prior vaccination was reported from Milwaukee in 2005. We report a second unvaccinated patient who showed early recovery from rabies and then died accidentally during convalescence, providing an unparalleled opportunity to examine the histopathology as well as immune and virological correlates of early recovery from human rabies. Methods Case report, rapid fluorescent focus inhibition test, enzyme-linked immunosorbent assay, indirect and direct fluorescent antibody assays, reverse-transcriptase polymerase chain reaction, phylogenetic reconstruction, isolation in tissue culture, pathology and immunohistochemistry. Results The 9 year old died 76 days after presenting with rabies of vampire bat phylogeny transmitted by cat bite. Antibody response in serum and cerebrospinal fluid was robust and associated with severe cerebral edema. No rabies virus was cultured at autopsy. Rabies virus antigen was atypical in size and distribution. Rabies virus genome was present in neocortex but absent in brainstem. Conclusions Clinical recovery was associated with detection of neutralizing antibody and clearance of infectious rabies virus in the central nervous system by 76 days but not clearance of detectable viral subcomponents such as nucleoprotein antigen or RNA in brain. PMID:25405805

Population pharmacokinetics and pharmacodynamics of enoxaparin in unstable angina and non-ST-segment elevation myocardial infarction

PubMed Central

Bruno, René; Baille, Pascale; Retout, Sylvie; Vivier, Nicole; Veyrat-Follet, Christine; Sanderink, Ger-Jan; Becker, Richard; Antman, Elliott M

2003-01-01

Aims A major concern with any antithrombotic therapy is an increase in the risk of haemorrhage. The aim of this study was to analyse population pharmacokinetics and pharmacokinetic/pharmacodynamic (PK/PD) relationships for enoxaparin in patients with unstable angina (UA) and non-ST-segment elevation myocardial infarction (NSTEMI), which may help predict risk of haemorrhage. Methods Anti-factor Xa (anti-Xa) activity was measured as marker of enoxaparin concentration in 448 patients receiving the drug as a single 30-mg intravenous bolus followed by 1.0 or 1.25 mg kg−1 subcutaneously twice a day. A population pharmacokinetic analysis was conducted and individual estimates of enoxaparin clearance and area under the curve were tested as prognostic factors for the occurrence of haemorrhagic episodes. Results Basic population PK parameters were an enoxaparin clearance of 0.733 l h−1[95% confidence interval (CI) 0.698, 0.738], a distribution volume of 5.24 l (95% CI 4.20, 6.28) and an elimination half-life of 5.0 h. Enoxaparin clearance was significantly related to patient weight and creatinine clearance, and was the only independent predictor of experiencing both all (10.7%, P = 0.0013) and major (2.2%, P = 0.0004) haemorrhagic events. A creatinine clearance of 30 ml min−1 was associated with a decrease in enoxaparin clearance of 27% compared with that in a patient with a median creatinine clearance of 88 ml min−1, and was related to a 1.5- and 3.8-fold increase in the risk of ‘all’ and ‘major’ haemorrhagic episodes, respectively. Conclusions Enoxaparin clearance depends on body weight, and, therefore, weight-adjusted dosing is recommended to minimize interpatient variability in drug exposure and the risk of haemorrhage. The importance of an increased risk of haemorrhage with decreasing renal function must be weighed against the benefit of treatment with enoxaparin in patients with UA and NSTEMI. PMID:12968985

Digging more in the genetic risk prediction of hepatitis C virus epidemic in Egypt: Apoptosis genes polymorphisms in the susceptibility of hepatitis C virus and association with viral load.

PubMed

Khalifa, Rania H; Shahin, Rasha Mohamad Hosny; Aboukhalil, Reham Emad Eldin; Marie, Mohamed A; El-Deeb, Amr M; Riad, Nermine Magdi

2017-06-15

Egypt is confronted with the highest hepatitis C virus (HCV) epidemic. Apoptosis and cellular immune responses are crucial to the clearance or persistence of viral infections. This case-control study was carried out to detect whether apoptosis genes single nucleotide polymorphisms (SNPs) confer risk to HCV in a cohort of Egyptian patients and to explore their association with viral load. One hundred and ninety six blood samples were withdrawn from 96 HCV patients and 100 controls. The Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) -1525G>A and FasL-844T>C SNPs were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Hepatitis C viral load was measured using Real time PCR. Results Genotypes distributions of TRAIL -1525G>A and FasL-844 T>C polymorphisms in controls were in accordance with Hardy-Weinberg equilibrium (p>0.05). The study showed a statistically significant difference in the distribution of the TRAIL -1525G>A polymorphism genotypes and the FasL-844 T>C polymorphism genotypes between the HCV patients and the controls (p=0.001 and 0.02 respectively), with association of the -1525GA genotype and -844 TT genotype with increased risk of HCV infection (OR=2.68, 1.942 respectively, 95% CI=1.482-4.846, 1.1-3.43, respectively). No significant association was detected between TRAIL, FasL and the viral load. Our results suggest that the FasL -844T>C SNP is implicated in the susceptibility to HCV in Egyptian patients and firstly report the involvement of TRAIL gene polymorphism in the risk of the disease. Therefore we recommend national programs to delineate genetic factors that may put individuals at risk for contracting HCV. Copyright © 2017 Elsevier B.V. All rights reserved.

Risk factors for long-term persistence of serum hepatitis B surface antigen following acute hepatitis B virus infection in Japanese adults.

PubMed

Ito, Kiyoaki; Yotsuyanagi, Hiroshi; Yatsuhashi, Hiroshi; Karino, Yoshiyasu; Takikawa, Yasuhiro; Saito, Takafumi; Arase, Yasuji; Imazeki, Fumio; Kurosaki, Masayuki; Umemura, Takeji; Ichida, Takafumi; Toyoda, Hidenori; Yoneda, Masashi; Mita, Eiji; Yamamoto, Kazuhide; Michitaka, Kojiro; Maeshiro, Tatsuji; Tanuma, Junko; Tanaka, Yasuhito; Sugiyama, Masaya; Murata, Kazumoto; Masaki, Naohiko; Mizokami, Masashi

2014-01-01

The proportion of patients who progress to chronicity following acute hepatitis B (AHB) varies widely worldwide. Moreover, the association between viral persistence after AHB and hepatitis B virus (HBV) genotypes in adults remains unclear. A nationwide multicenter study was conducted throughout Japan to evaluate the influence of clinical and virological factors on chronic outcomes in patients with AHB. For comparing factors between AHB patients with viral persistence and those with self-limited infection, 212 AHB patients without human immunodeficiency virus (HIV) coinfection were observed in 38 liver centers until serum hepatitis B surface antigen (HBsAg) disappeared or a minimum of 6 months in cases where HBsAg persisted. The time to disappearance of HBsAg was significantly longer for genotype A patients than that of patients infected with non-A genotypes. When chronicity was defined as the persistence of HBsAg positivity for more than 6 or 12 months, the rate of progression to chronicity was higher in patients with genotype A, although many cases caused by genotype A were prolonged cases of AHB, rather than chronic infection. Multivariate logistic regression analysis revealed only genotype A was independently associated with viral persistence following AHB. A higher peak level of HBV DNA and a lower peak of alanine aminotransferase (ALT) levels were characteristics of AHB caused by genotype A. Treatment with nucleotide analogs (NAs) did not prevent progression to chronic infection following AHB overall. Subanalysis suggested early NA initiation may enhance the viral clearance. Genotype A was an independent risk factor for progression to chronic infection following AHB. Our data will be useful in elucidating the association between viral persistence after AHB, host genetic factors, and treatment with NAs in future studies. © 2013 by the American Association for the Study of Liver Diseases.

HLA-B*27 subtype specificity determines targeting and viral evolution of a hepatitis C virus-specific CD8+ T cell epitope.

PubMed

Nitschke, Katja; Barriga, Alejandro; Schmidt, Julia; Timm, Jörg; Viazov, Sergei; Kuntzen, Thomas; Kim, Arthur Y; Lauer, Georg M; Allen, Todd M; Gaudieri, Silvana; Rauch, Andri; Lange, Christian M; Sarrazin, Christoph; Eiermann, Thomas; Sidney, John; Sette, Alessandro; Thimme, Robert; López, Daniel; Neumann-Haefelin, Christoph

2014-01-01

HLA-B*27 is associated with spontaneous HCV genotype 1 clearance. HLA-B*27-restricted CD8+ T cells target three NS5B epitopes. Two of these epitopes are dominantly targeted in the majority of HLA-B*27+ patients. In chronic infection, viral escape occurs consistently in these two epitopes. The third epitope (NS5B2820) was dominantly targeted in an acutely infected patient. This was in contrast, however, to the lack of recognition and viral escape in the large majority of HLA-B*27+ patients. Here, we set out to determine the host factors contributing to selective targeting of this epitope. Four-digit HLA class I typing and viral sequence analyses were performed in 78 HLA-B*27+ patients with chronic HCV genotype 1 infection. CD8+ T cell analyses were performed in a subset of patients. In addition, HLA/peptide affinity was compared for HLA-B*27:02 and 05. The NS5B2820 epitope is only restricted by the HLA-B*27 subtype HLA-B*27:02 (that is frequent in Mediterranean populations), but not by the prototype HLA-B*27 subtype B*27:05. Indeed, the epitope is very dominant in HLA-B*27:02+ patients and is associated with viral escape mutations at the anchor position for HLA-binding in 12 out of 13 HLA-B*27:02+ chronically infected patients. The NS5B2820 epitope is immunodominant in the context of HLA-B*27:02, but is not restricted by other HLA-B*27 subtypes. This finding suggests an important role of HLA subtypes in the restriction of HCV-specific CD8+ responses. With minor HLA subtypes covering up to 39% of specific populations, these findings may have important implications for the selection of epitopes for global vaccines. Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Variable RNA expression from recently acquired, endogenous viral elements (EVE) of white spot syndrome virus (WSSV) in shrimp.

PubMed

Utari, Heny Budi; Soowannayan, Chumporn; Flegel, Timothy W; Whityachumnarnkul, Boonsirm; Kruatrachue, Maleeya

2017-11-01

The viral accommodation hypothesis proposes that endogenous viral elements (EVE) from both RNA and DNA viruses are being continually integrated into the shrimp genome by natural host processes and that they can result in tolerance to viral infection by fortuitous production of antisense, immunospecific RNA (imRNA). Thus, we hypothesized that previously reported microarray results for the presence of white spot syndrome virus (WSSV) open reading frames (ORFs) formerly called 151, 366 and 427 in a domesticated giant tiger shrimp (Penaeus monodon) breeding stock might have represented expression from EVE, since the stock had shown uninterrupted freedom from white spot disease (WSD) for many generations. To test this hypothesis, 128 specimens from a current stock generation were confirmed for freedom from WSSV infection using two nested PCR detection methods. Subsequent nested-PCR testing revealed 33/128 specimens (26%) positive for at least one of the ORF at very high sequence identity (95-99%) to extant WSSV. Positive results for ORF 366 (now known to be a fragment of the WSSV capsid protein gene) dominated (28/33 = 84.8%), so 9 arbitrarily selected 366-positive specimens were tested by strand-specific, nested RT-PCR using DNase-treated RNA templates. This revealed variable RNA expression in individual shrimp including no RNA transcripts (n = 1), sense transcripts only (n = 1), antisense transcripts only (n = 2) or transcripts of both sense (n = 5). The latter 7 expression products indicated specimens producing putative imRNA. The variable types and numbers of the EVE and the variable RNA expression (including potential imRNA) support predictions of the viral accommodation hypothesis that EVE are randomly produced and expressed. Positive nested PCR test results for EVE of ORF 366 using DNA templates derived from shrimp sperm (germ cells), indicated that they were heritable. Copyright © 2017 Elsevier Ltd. All rights reserved.

An RNAi in silico approach to find an optimal shRNA cocktail against HIV-1

PubMed Central

2010-01-01

Background HIV-1 can be inhibited by RNA interference in vitro through the expression of short hairpin RNAs (shRNAs) that target conserved genome sequences. In silico shRNA design for HIV has lacked a detailed study of virus variability constituting a possible breaking point in a clinical setting. We designed shRNAs against HIV-1 considering the variability observed in naïve and drug-resistant isolates available at public databases. Methods A Bioperl-based algorithm was developed to automatically scan multiple sequence alignments of HIV, while evaluating the possibility of identifying dominant and subdominant viral variants that could be used as efficient silencing molecules. Student t-test and Bonferroni Dunn correction test were used to assess statistical significance of our findings. Results Our in silico approach identified the most common viral variants within highly conserved genome regions, with a calculated free energy of ≥ -6.6 kcal/mol. This is crucial for strand loading to RISC complex and for a predicted silencing efficiency score, which could be used in combination for achieving over 90% silencing. Resistant and naïve isolate variability revealed that the most frequent shRNA per region targets a maximum of 85% of viral sequences. Adding more divergent sequences maintained this percentage. Specific sequence features that have been found to be related with higher silencing efficiency were hardly accomplished in conserved regions, even when lower entropy values correlated with better scores. We identified a conserved region among most HIV-1 genomes, which meets as many sequence features for efficient silencing. Conclusions HIV-1 variability is an obstacle to achieving absolute silencing using shRNAs designed against a consensus sequence, mainly because there are many functional viral variants. Our shRNA cocktail could be truly effective at silencing dominant and subdominant naïve viral variants. Additionally, resistant isolates might be targeted under specific antiretroviral selective pressure, but in both cases these should be tested exhaustively prior to clinical use. PMID:21172023

Metabolic and anthropometric parameters contribute to ART-mediated CD4+ T cell recovery in HIV-1-infected individuals: an observational study.

PubMed

Azzoni, Livio; Foulkes, Andrea S; Firnhaber, Cynthia; Yin, Xiangfan; Crowther, Nigel J; Glencross, Deborah; Lawrie, Denise; Stevens, Wendy; Papasavvas, Emmanouil; Sanne, Ian; Montaner, Luis J

2011-07-29

The degree of immune reconstitution achieved in response to suppressive ART is associated with baseline individual characteristics, such as pre-treatment CD4 count, levels of viral replication, cellular activation, choice of treatment regimen and gender. However, the combined effect of these variables on long-term CD4 recovery remains elusive, and no single variable predicts treatment response. We sought to determine if adiposity and molecules associated with lipid metabolism may affect the response to ART and the degree of subsequent immune reconstitution, and to assess their ability to predict CD4 recovery. We studied a cohort of 69 (48 females and 21 males) HIV-infected, treatment-naïve South African subjects initiating antiretroviral treatment (d4T, 3Tc and lopinavir/ritonavir). We collected information at baseline and six months after viral suppression, assessing anthropometric parameters, dual energy X-ray absorptiometry and magnetic resonance imaging scans, serum-based clinical laboratory tests and whole blood-based flow cytometry, and determined their role in predicting the increase in CD4 count in response to ART. We present evidence that baseline CD4+ T cell count, viral load, CD8+ T cell activation (CD95 expression) and metabolic and anthropometric parameters linked to adiposity (LDL/HDL cholesterol ratio and waist/hip ratio) significantly contribute to variability in the extent of CD4 reconstitution (ΔCD4) after six months of continuous ART. Our final model accounts for 44% of the variability in CD4+ T cell recovery in virally suppressed individuals, representing a workable predictive model of immune reconstitution.

Effects of Long-duration Space Flight on Toe Clearance During Treadmill Walking

NASA Technical Reports Server (NTRS)

Miller, Chris; Peters, Brian; Brady, Rachel; Mulavara, Ajitkumar; Richards, Jason; Hayat, Matthew; Bloomberg, Jacob

2008-01-01

Upon returning from long-duration space flight, astronauts and cosmonauts must overcome physiologic and sensorimotor changes induced by prolonged exposure to microgravity as they readapt to a gravitational environment. Their compromised balance and coordination lead to an altered and more variable walking pattern (Bloomberg & Mulavara, 2003; McDonald, et al., 1996). Toe trajectory during the swing phase of locomotion has been identified as a precise motor control task (Karst, et al., 1999), thus providing an indication of the coordination of the lower limbs (Winter, 1992). Failure to achieve sufficient toe clearance may put the crew member at a greater risk of tripping and falling, especially if an emergency egress from the vehicle should be necessary upon landing. The purpose of this study was to determine the pre- to post-flight changes in toe clearance in crew members returning from long-duration missions and the recovery thereafter.

Bridging basic science and clinical research: the EASL Monothematic Conference on Translational Research in Viral Hepatitis.

PubMed

Boettler, Tobias; Moradpour, Darius; Thimme, Robert; Zoulim, Fabien

2014-09-01

The EASL Monothematic Conference on Translational Research in Viral Hepatitis brought together a group of leading scientists and clinicians working on both, basic and clinical aspects of viral hepatitis, thereby building bridges from bench to bedside. This report recapitulates the presentations and discussions at the conference held in Lyon, France on November 29-30, 2013. In recent years, great advances have been made in the field of viral hepatitis, particularly in hepatitis C virus (HCV) infection. The identification of IL28B genetic polymorphisms as a major determinant for spontaneous and treatment-induced HCV clearance was a seminal discovery. Currently, hepatologists are at the doorstep of even greater advances, with the advent of a wealth of directly acting antivirals (DAAs) against HCV. Indeed, promising results have accumulated over the last months and few years, showing sustained virological response (SVR) rates of up to 100% with interferon-free DAA combination therapies. Thus, less than 25 years after its identification, HCV infection may soon be curable in the vast majority of patients, highlighting the great success of HCV research over the last decades. However, viral hepatitis and its clinical complications such as liver cirrhosis and hepatocellular carcinoma (HCC) remain major global challenges. New therapeutic strategies to tackle hepatitis B virus (HBV) and hepatitis D virus (HDV) infection are needed, as current therapies have undeniable limitations. Nucleoside/nucleotide analogues (NUC) can efficiently control HBV replication and reduce or even reverse liver damage. However, these drugs have to be given for indefinite periods in most patients to maintain virological and biochemical responses. Although sustained responses off treatment can be achieved by treatment with (pegylated) interferon-α, only about 10-30% of patients effectively resolve chronic hepatitis B. It was the goal of this conference to review the progress made over the last years in chronic viral hepatitis research and to identify key questions that need to be addressed in order to close the gap between basic and clinical research and to develop novel preventive and treatment approaches for this most common cause of liver cirrhosis and HCC. Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Population Pharmacokinetics of Atazanavir in Patients with Human Immunodeficiency Virus Infection▿

PubMed Central

Colombo, Sara ; Buclin, Thierry; Cavassini, Matthias; Décosterd, Laurent A.; Telenti, Amalio; Biollaz, Jérôme; Csajka, Chantal

2006-01-01

Atazanavir (ATV) is a new azapeptide protease inhibitor recently approved and currently used at a fixed dose of either 300 mg once per day (q.d.) in combination with 100 mg ritonavir (RTV) or 400 mg q.d. without boosting. ATV is highly bound to plasma proteins and extensively metabolized by CYP3A4. Since ATV plasma levels are highly variable and seem to be correlated with both viral response and toxicity, dosage individualization based on plasma concentration monitoring might be indicated. This study aimed to assess the ATV pharmacokinetic profile in a target population of HIV patients, to characterize interpatient and intrapatient variability, and to identify covariates that might influence ATV disposition. A population analysis was performed with NONMEM with 574 plasma samples from a cohort of 214 randomly selected patients receiving ATV. A total of 346 randomly collected ATV plasma levels and 19 full concentration-time profiles at steady state were available. The pharmacokinetic parameter estimates were an oral clearance (CL) of 12.9 liters/h (coefficient of variation [CV], 26%), a volume of distribution of 88.3 liters (CV, 29%), an absorption rate constant of 0.405 h−1 (CV, 122%), and a lag time of 0.88 h. A relative bioavailability value was introduced to account for undercompliance due to infrequent follow-ups (0.81; CV, 45%). Among the covariates tested, only RTV significantly reduced CL by 46%, thereby increasing the ATV elimination half-life from 4.6 h to 8.8 h. The pharmacokinetic parameters of ATV were adequately described by a one-compartment population model. The concomitant use of RTV improved the pharmacokinetic profile. However, the remaining high interpatient variability suggests the possibility of an impact of unmeasured covariates, such as genetic traits or environmental influences. This population pharmacokinetic model, together with therapeutic drug monitoring and Bayesian dosage adaptation, can be helpful in the selection and adaptation of ATV doses. PMID:16940065

Detection of minute virus of mice using real time quantitative PCR in assessment of virus clearance during the purification of Mammalian cell substrate derived biotherapeutics.

PubMed

Zhan, Dejin; Roy, Margaret R; Valera, Christine; Cardenas, Jesse; Vennari, Joann C; Chen, Janice W; Liu, Shengjiang

2002-12-01

A real time quantitative PCR assay has been developed for detecting minute virus of mice (MVM). This assay directly quantifies PCR product by monitoring the increase of fluorescence intensity emitted during enzymatic hydrolysis of an oligonucleotide probe labelled covalently with fluorescent reporting and quenching dyes via Taq polymerase 5'-->3' exonuclease activity. The quantity of MVM DNA molecules in the samples was determined using a known amount of MVM standard control DNA fragment cloned into a plasmid (pCR-MVM). We have demonstrated that MVM TaqMan PCR assay is approximately 1000-fold more sensitive than the microplate infectivity assay with the lowest detection limit of approximately one particle per reaction. The reliable detection range is within 100 to 10(9) molecules per reaction with high reproducibility. The intra assay variation is <2.5%, and the inter assays variation is <6.5% when samples contain >100 particles/assay. When we applied the TaqMan PCR to MVM clearance studies done by column chromatography or normal flow viral filtration, we found that the virus removal factors were similar to that of virus infectivity assay. It takes about a day to complete entire assay processes, thus, the TaqMan PCR assay is at least 10-fold faster than the infectivity assay. Therefore, we concluded that this fast, specific, sensitive, and robust assay could replace the infectivity assay for virus clearance evaluation. Copyright 2002 The International Association for Biologicals. Published by Elsevier Science Ltd. All rights reserved.

Modulation of Experimental Herpes Encephalitis-Associated Neurotoxicity through Sulforaphane Treatment

PubMed Central

Schachtele, Scott J.; Hu, Shuxian; Lokensgard, James R.

2012-01-01

Reactive oxygen species (ROS) produced by brain-infiltrating macrophages and neutrophils, as well as resident microglia, are pivotal to pathogen clearance during viral brain infection. However, unchecked free radical generation is also responsible for damage to and cytotoxicity of critical host tissue bystander to primary infection. These unwanted effects of excessive ROS are combated by local cellular production of antioxidant enzymes, including heme oxygenase-1 (HO-1) and glutathione peroxidase 1 (Gpx1). In this study, we showed that experimental murine herpes encephalitis triggered robust ROS production, as well as an opposing upregulation of the antioxidants HO-1 and Gpx1. This antioxidant response was insufficient to prevent tissue damage, neurotoxicity, and mortality associated with viral brain infection. Previous studies corroborate our data supporting astrocytes as the major antioxidant producer in brain cell cultures exposed to HSV-1 stimulated microglia. We hypothesized that stimulating opposing antioxidative responses in astrocytes, as well as neurons, would mitigate the effects of ROS-mediated neurotoxicity both in vitro and during viral brain infection in vivo. Here, we demonstrate that the addition of sulforaphane, a potent stimulator of antioxidant responses, enhanced HO-1 and Gpx1 expression in astrocytes through the activation of nuclear factor-E2-related factor 2 (Nrf2). Additionally, sulforaphane treatment was found to be effective in reducing neurotoxicity associated with HSV-stimulated microglial ROS production. Finally, intraperitoneal injections of sulforaphane into mice during active HSV infection reduced neuroinflammation via a decrease in brain-infiltrating leukocytes, macrophage- and neutrophil-produced ROS, and MHCII-positive, activated microglia. These data support a key role for astrocyte-produced antioxidants in modulating oxidative stress and neuronal damage in response to viral infection. PMID:22558388

Latent infection by γherpesvirus stimulates profibrotic mediator release from multiple cell types.

PubMed

Stoolman, Joshua S; Vannella, Kevin M; Coomes, Stephanie M; Wilke, Carol A; Sisson, Thomas H; Toews, Galen B; Moore, Bethany B

2011-02-01

Although γherpesvirus infections are associated with enhanced lung fibrosis in both clinical and animal studies, there is limited understanding about fibrotic effects of γherpesviruses on cell types present in the lung, particularly during latent infection. Wild-type mice were intranasally infected with a murine γherpesvirus (γHV-68) or mock-infected with saline. Twenty-eight days postinfection (dpi), ∼14 days following clearance of the lytic infection, alveolar macrophages (AMs), mesenchymal cells, and CD19-enriched cell populations from the lung and spleen express M(3) and/or glycoprotein B (gB) viral mRNA and harbor viral genome. AMs from infected mice express more transforming growth factor (TGF)-β(1), CCL2, CCL12, TNF-α, and IFN-γ than AMs from mock-infected mice. Mesenchymal cells express more total TGF-β(1), CCL12, and TNF-α than mesenchymal cells from mock-infected mice. Lung and spleen CD19-enriched cells express more total TGF-β(1) 28 dpi compared with controls. The CD19-negative fraction of the spleen overexpresses TGF-β(1) and harbors viral genome, but this likely represents infection of monocytes. Purified T cells from the lung harbor almost no viral genome. Purified T cells overexpress IL-10 but not TGF-β(1). Intracellular cytokine staining demonstrated that lung T cells at 28 dpi produce IFN-γ but not IL-4. Thus infection with a murine γherpesvirus is sufficient to upregulate profibrotic and proinflammatory factors in a variety of lung resident and circulating cell types 28 dpi. Our results provide new information about possible contributions of these cells to fibrogenesis in the lungs of individuals harboring a γherpesvirus infection and may help explain why γHV-68 infection can augment or exacerbate fibrotic responses in mice.

Is HCV core antigen a reliable marker of viral load? An evaluation of HCV core antigen automated immunoassay

PubMed Central

Hadziyannis, Emilia; Minopetrou, Martha; Georgiou, Anastasia; Spanou, Fotini; Koskinas, John

2013-01-01

Background Hepatitis C viral (HCV) load detection and quantification is routinely accomplished by HCV RNA measurement, an expensive but essential test, both for the diagnosis and treatment of chronic hepatitis C (CHC). HCV core antigen (Ag) testing has been suggested as an attractive alternative to molecular diagnostics. The aim of the study was to evaluate an automated chemiluminescent immunoassay (CLIA) for HCV core Ag measurement in comparison to quantitative HCV RNA determination. Methods HCV Ag was measured in 105 anti-HCV positive patients, from which 89 were HCV RNA positive with CHC and 16 HCV RNA negative after spontaneous HCV clearance. Viral load was quantified with branched DNA (bDNA, Versant, Siemens). Sera were stored at -70°C and then tested with the Architect HCV Ag test (Abbott Laboratories), a two-step CLIA assay, with high throughput and minimal handling of the specimens. Statistical analysis was performed on logarithmically transformed values. Results HCV-Ag was detectable and quantifiable in 83/89 and in grey zone in 4/89 HCV RNA positive sera. HCV-Ag was undetectable in all 16 HCV RNA negative samples. The sample with the lowest viral load that tested positive for HCV-Ag contained 1200 IU/mL HCV RNA. There was a positive correlation between HCV RNA and HCV-Ag (r=0.89). The HCV RNA/ HCV Ag ratio varied from 1.5 to 3.25. Conclusion The HCV core Ag is an easy test with comparable sensitivity (>90%) and satisfactory correlation with the HCV RNA bDNA assay. Its role in diagnostics and other clinical applications has to be determined based on cost effectiveness. PMID:24714621

SCREENING OF PROTEASE INHIBITORS RESISTANCE MUTATIONS IN HEPATITIS C VIRUS ISOLATES INFECTING ROMANIAN PATIENTS UNEXPOSED TO TRIPLE THERAPY.

PubMed

Dinu, Sorin; Calistru, Petre-Iacob; Ceauşu, Emanoil; Târdeil, Graţiela; Oprişan, Gabriela

2015-01-01

Although the European recommendations include the use of new antiviral drugs for the treatment of hepatitis C, in Romania the current treatment remains interferon plus ribavirin. First generation viral protease inhibitors (i.e. boceprevir, telaprevir), which have raised the chances of obtaining viral clearance in up to 70% of infection cases produced by genotype 1 isolates, have not been introduced yet as standard treatment in our country. The success of these new antivirals is limited by the occurrence and selection of resistance mutations during therapy. We set-up a molecular study aiming to detect any resistance mutations to boceprevir and telaprevir harbored by hepatitis C isolates infecting Romanian patients naïve to viral protease inhibitors. Since these new antivirals are efficient and approved for genotype 1 infection, viral samples were genotyped following a protocol previously developed by our research group. We analyzed by both population sequencing and molecular cloning and sequencing the NS3 protease region of hepatitis C virus isolates infecting patients which were not previously exposed to boceprevir and telaprevir. All the analyzed samples were subtype 1b and resembled the samples collected in recent years from Romanian patients. Molecular cloning followed by sequencing showed great intra-host diversity, which is known to represent the source of isolates with different resistance phenotypes. Both population sequencing and molecular cloning followed by clone sequencing revealed two boceprevir resistance mutations (T54S and V55A), respectively, a telaprevir resistance mutation (T54S) in the sequences obtained from a patient with chronic hepatitis C. To our knowledge, this is the first study indicating the existence of pre-treatment resistance mutations to boceprevir and telaprevir in hepatitis C virus isolates infecting Romanian patients.

Eradicating hepatitis C virus ameliorates insulin resistance without change in adipose depots.

PubMed

Milner, K-L; Jenkins, A B; Trenell, M; Tid-Ang, J; Samocha-Bonet, D; Weltman, M; Xu, A; George, J; Chisholm, D J

2014-05-01

Chronic hepatitis C (CHC) is associated with lipid-related changes and insulin resistance; the latter predicts response to antiviral therapy, liver disease progression and the risk of diabetes. We sought to determine whether insulin sensitivity improves following CHC viral eradication after antiviral therapy and whether this is accompanied by changes in fat depots or adipokine levels. We compared 8 normoglycaemic men with CHC (genotype 1 or 3) before and at least 6 months post viral eradication and 15 hepatitis C antibody negative controls using an intravenous glucose tolerance test and two-step hyperinsulinaemic-euglycaemic clamp with [6,6-(2) H2 ] glucose to assess peripheral and hepatic insulin sensitivity. Magnetic resonance imaging and spectroscopy quantified abdominal fat compartments, liver and intramyocellular lipid. Peripheral insulin sensitivity improved (glucose infusion rate during high-dose insulin increased from 10.1 ± 1.6 to 12 ± 2.1 mg/kg/min/, P = 0.025), with no change in hepatic insulin response following successful viral eradication, without any accompanying change in muscle, liver or abdominal fat depots. There was corresponding improvement in incremental glycaemic response to intravenous glucose (pretreatment: 62.1 ± 8.3 vs post-treatment: 56.1 ± 8.5 mm, P = 0.008). Insulin sensitivity after viral clearance was comparable to matched controls without CHC. Post therapy, liver enzyme levels decreased but, interestingly, levels of glucagon, fatty acid-binding protein and lipocalin-2 remained elevated. Eradication of the hepatitis C virus improves insulin sensitivity without alteration in fat depots, adipokine or glucagon levels, consistent with a direct link of the virus with insulin resistance. © 2013 John Wiley & Sons Ltd.

Lessons learned from a double-blind randomised placebo-controlled study with a iota-carrageenan nasal spray as medical device in children with acute symptoms of common cold.

PubMed

Fazekas, Tamas; Eickhoff, Philipp; Pruckner, Nathalie; Vollnhofer, Georg; Fischmeister, Gustav; Diakos, Christopher; Rauch, Margit; Verdianz, Maria; Zoubek, Andreas; Gadner, Helmut; Lion, Thomas

2012-09-05

Common cold is caused by a variety of respiratory viruses. The prevalence in children is high, and it potentially contributes to significant morbidity. Iota-carragenan, a polymer derived from red seaweed, has reduced viral load in nasal secretions and alleviated symptoms in adults with common cold. We have assessed the antiviral and therapeutic activity of a nasal spray containing iota-carrageenan in children with acute symptoms of common cold. A cohort of 153 children between 1-18 years (mean age 5 years), displaying acute symptoms of common cold were randomly assigned to treatment with a nasal spray containing iota-carrageenan (0.12%) as verum or 0.9% sodium chloride solution as placebo for seven days. Symptoms of common cold were recorded and the viral load of respiratory viruses in nasal secretions was determined at two consecutive visits. The results of the present study showed no significant difference between the iota carrageenan and the placebo group on the mean of TSS between study days 2-7. Secondary endpoints, such as reduced time to clearance of disease (7.6 vs 9.4 days; p = 0.038), reduction of viral load (p = 0.026), and lower incidence of secondary infections with other respiratory viruses (p = 0.046) indicated beneficial effects of iota-carrageenan in this population. The treatment was safe and well tolerated, with less side effects observed in the verum group compared to placebo. In this study iota-carrageenan did not alleviate symptoms in children with acute symptoms of common cold, but significantly reduced viral load in nasal secretions that may have important implications for future studies. ISRCTN52519535, http://www.controlled-trials.com/ISRCTN52519535/

Population pharmacokinetics of intravenous Erwinia asparaginase in pediatric acute lymphoblastic leukemia patients.

PubMed

Sassen, Sebastiaan D T; Mathôt, Ron A A; Pieters, Rob; Kloos, Robin Q H; de Haas, Valérie; Kaspers, Gertjan J L; van den Bos, Cor; Tissing, Wim J E; Te Loo, Maroeska; Bierings, Marc B; Kollen, Wouter J W; Zwaan, Christian M; van der Sluis, Inge M

2017-03-01

Erwinia asparaginase is an important component in the treatment of pediatric acute lymphoblastic leukemia. A large variability in serum concentrations has been observed after intravenous Erwinia asparaginase. Currently, Dutch Childhood Oncology Group protocols dose alterations are based on trough concentrations to ensure adequate asparaginase activity (≥100 IU/L). The aim of this study was to describe the population pharmacokinetics of intravenous Erwinia asparaginase to quantify and gather insight into inter-individual and inter-occasion variability. The starting dose was evaluated on the basis of the derived population pharmacokinetic parameters. In a multicenter prospective observational study, a total of 714 blood samples were collected from 51 children (age 1-17 years) with acute lymphoblastic leukemia. The starting dose was 20,000 IU/m 2 three times a week and adjusted according to trough levels from week three onwards. A population pharmacokinetic model was developed using NONMEM ® A 2-compartment linear model with allometric scaling best described the data. Inter-individual and inter-occasion variability of clearance were 33% and 13%, respectively. Clearance in the first month of treatment was 14% higher ( P <0.01). Monte Carlo simulations with our pharmacokinetic model demonstrated that patients with a low weight might require higher doses to achieve similar concentrations compared to patients with high weight. The current starting dose of 20,000 IU/m 2 might result in inadequate concentrations, especially for smaller, lower weight patients, hence dose adjustments based on individual clearance are recommended. The protocols were approved by the institutional review boards. (Registered at NTR 3379 Dutch Trial Register; www.trialregister.nl). Copyright© Ferrata Storti Foundation.

HIV stigma and depressive symptoms are related to adherence and virological response to antiretroviral treatment among immigrant and indigenous HIV infected patients.

PubMed

Sumari-de Boer, I Marion; Sprangers, Mirjam A G; Prins, Jan M; Nieuwkerk, Pythia T

2012-08-01

We compared adherence to cART and virological response between indigenous and immigrant HIV-infected patients in the Netherlands, and investigated if a possible difference was related to a difference in the psychosocial variables: HIV-stigma, quality-of-life, depression and beliefs about medications. Psychosocial variables were assessed using validated questionnaires administered during a face-to-face interview. Adherence was assessed trough pharmacy-refill monitoring. We assessed associations between psychosocial variables and non-adherence and having detectable plasma viral load using logistic regression analyses. Two-hundred-two patients participated of whom 112 (55%) were immigrants. Viral load was detectable in 6% of indigenous patients and in 15% of the immigrants (P < 0.01). In multivariate analyses, higher HIV-stigma and prior virological failure were associated with non-adherence, and depressive symptoms, prior virological failure and non-adherence with detectable viral load. Our findings suggest that HIV-stigma and depressive symptoms may be targets for interventions aimed at improving adherence and virological response among indigenous and immigrant HIV-infected patients.

Iohexol clearance is superior to creatinine-based renal function estimating equations in detecting short-term renal function decline in chronic heart failure.

PubMed

Cvan Trobec, Katja; Kerec Kos, Mojca; von Haehling, Stephan; Anker, Stefan D; Macdougall, Iain C; Ponikowski, Piotr; Lainscak, Mitja

2015-12-01

To compare the performance of iohexol plasma clearance and creatinine-based renal function estimating equations in monitoring longitudinal renal function changes in chronic heart failure (CHF) patients, and to assess the effects of body composition on the equation performance. Iohexol plasma clearance was measured in 43 CHF patients at baseline and after at least 6 months. Simultaneously, renal function was estimated with five creatinine-based equations (four- and six-variable Modification of Diet in Renal Disease, Cockcroft-Gault, Cockcroft-Gault adjusted for lean body mass, Chronic Kidney Disease Epidemiology Collaboration equation) and body composition was assessed using bioimpedance and dual-energy x-ray absorptiometry. Over a median follow-up of 7.5 months (range 6-17 months), iohexol clearance significantly declined (52.8 vs 44.4 mL/[min ×1.73 m2], P=0.001). This decline was significantly higher in patients receiving mineralocorticoid receptor antagonists at baseline (mean decline -22% of baseline value vs -3%, P=0.037). Mean serum creatinine concentration did not change significantly during follow-up and no creatinine-based renal function estimating equation was able to detect the significant longitudinal decline of renal function determined by iohexol clearance. After accounting for body composition, the accuracy of the equations improved, but not their ability to detect renal function decline. Renal function measured with iohexol plasma clearance showed relevant decline in CHF patients, particularly in those treated with mineralocorticoid receptor antagonists. None of the equations for renal function estimation was able to detect these changes. ClinicalTrials.gov registration number: NCT01829880.

Population pharmacokinetics of rifampicin, pyrazinamide and isoniazid in children with tuberculosis: in silico evaluation of currently recommended doses.

PubMed

Zvada, Simbarashe P; Denti, Paolo; Donald, Peter R; Schaaf, H Simon; Thee, Stephanie; Seddon, James A; Seifart, Heiner I; Smith, Peter J; McIlleron, Helen M; Simonsson, Ulrika S H

2014-05-01

To describe the population pharmacokinetics of rifampicin, pyrazinamide and isoniazid in children and evaluate the adequacy of steady-state exposures. We used previously published data for 76 South African children with tuberculosis to describe the population pharmacokinetics of rifampicin, pyrazinamide and isoniazid. Monte Carlo simulations were used to predict steady-state exposures in children following doses in fixed-dose combination tablets in accordance with the revised guidelines. Reference exposures were derived from an ethnically similar adult population with tuberculosis taking currently recommended doses. The final models included allometric scaling of clearance and volume of distribution using body weight. Maturation was included for clearance of isoniazid and clearance and absorption transit time of rifampicin. For a 2-year-old child weighing 12.5 kg, the estimated typical oral clearances of rifampicin and pyrazinamide were 8.15 and 1.08 L/h, respectively. Isoniazid typical oral clearance (adjusted for bioavailability) was predicted to be 4.44, 11.6 and 14.6 L/h for slow, intermediate and fast acetylators, respectively. Higher oral clearance values in intermediate and fast acetylators also resulted from 23% lower bioavailability compared with slow acetylators. Simulations based on our models suggest that with the new WHO dosing guidelines and utilizing available paediatric fixed-dose combinations, children will receive adequate rifampicin exposures when compared with adults, but with a larger degree of variability. However, pyrazinamide and isoniazid exposures in many children will be lower than in adults. Further studies are needed to confirm these findings in children administered the revised dosages and to optimize pragmatic approaches to dosing.

Long-term follow up of feline leukemia virus infection and characterization of viral RNA loads using molecular methods in tissues of cats with different infection outcomes.

PubMed

Helfer-Hungerbuehler, A Katrin; Widmer, Stefan; Kessler, Yvonne; Riond, Barbara; Boretti, Felicitas S; Grest, Paula; Lutz, Hans; Hofmann-Lehmann, Regina

2015-02-02

It is a remarkable feature for a retrovirus that an infection with feline leukemia virus (FeLV) can result in various outcomes. Whereas some cats contain the infection and show a regressive course, others stay viremic and succumb to the infection within a few years. We hypothesized, that differences in the infection outcome might be causally linked to the viral RNA and provirus loads within the host and these loads therefore may give additional insight into the pathogenesis of the virus. Thus, the goals of the present study were to follow-up on experimentally infected cats and investigate tissues from cats with different infection outcomes using sensitive, specific TaqMan real-time PCR and reverse transcriptase (RT)-PCR. Nineteen experimentally FeLV-A/Glasgow-1-infected cats were categorized into having regressive, progressive or reactivated FeLV infection according to follow-up of FeLV p27 antigen detection in the blood. Remarkably, regressively infected cats showed detectable provirus and viral RNA loads in almost all of the 27 tested tissues, even many years after virus exposure. Moreover, some regressively infected cats reactivated the infection, and these cats had intermediate to high viral RNA and provirus tissue loads. The highest loads were found in viremic cats, independent of their health status. Tissues that represented sites of virus replication and shedding revealed the highest viral RNA and provirus loads, while the lowest loads were present in muscle and nerve tissues. A supplementary analysis of 20 experimentally infected cats with progressive infection revealed a median survival time of 3.1 years (range from 0.6 to 6.5 years); ∼70% (n=14) of these cats developed lymphoma, while leukemia and non-regenerative anemia were observed less frequently. Our results demonstrate that the different infection outcomes are associated with differences in viral RNA and provirus tissue loads. Remarkably, no complete clearance of FeLV viral RNA or provirus was detected in cats with regressive infection, even up to 12 years after exposure. In several cases FeLV reactivation could be observed. Thus, retroviruses integrated as provirus into the host's genome, could not be eliminated completely by the host and maintained their full potential for replication and reactivation. Copyright © 2014 Elsevier B.V. All rights reserved.

System-Level Design of a Shape Memory Alloy Actuator for Active Clearance Control in the High-Pressure Turbine

NASA Technical Reports Server (NTRS)

DeCastro, Jonathan A.; Melcher, Kevin J.; Noebe, Ronald D.

2005-01-01

This paper describes results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 inches. Design results show that an actuator comprised of 10 wires 2 inches in length is adequate for control at critical engine operating points and still exhibits acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

Population pharmacokinetic study of isepamicin with intensive care unit patients.

PubMed Central

Tod, M; Padoin, C; Minozzi, C; Cougnard, J; Petitjean, O

1996-01-01

The pharmacokinetics (PK) of isepamicin, a new aminoglycoside, were studied in 85 intensive care unit (ICU) patients and were compared with those observed in 10 healthy volunteers. A parametric method based on a nonlinear mixed-effect model was used to assess population PK. Isepamicin was given intravenously over 0.5 h at dosages of 15 mg/kg once daily or 7.5 mg/kg twice daily. The data were fitted to a bicompartmental open model. Compared with healthy volunteers, the mean values of the PK parameters were profoundly modified in ICU patients: elimination clearance was reduced by 48%, the volume of distribution in the central compartment (Vc) was increased by 50%, the peripheral volume of distribution was 70% higher, the distribution clearance was 146% lower, and the elimination half-life was ca. 3.4 times higher. The interindividual variability in PK parameters was about 50% in ICU patients. Five covariates (body weight [BW], simplified acute physiology score [SAPS], temperature, serum creatinine level, and creatinine clearance [CLCR]) were tentatively correlated with PK parameters by multivariate linear regression analysis with stepwise addition and deletion. The variability of isepamicin clearance was explained by three covariates (BW, SAPS, and CLCR), that of Vc was explained by BW and SAPS, and that of the elimination half-life was explained by CLCR and SAPS. Simulation of the concentration-versus-time profile for 500 individuals showed that the mean peak (0.75 h) concentration was 18% lower in ICU patients than in healthy volunteers and that the range in ICU patients was very broad (28.4 to 95.4 mg/liter). Therefore, monitoring of the isepamicin concentration is in ICU patients is mandatory. PMID:8849264

Population Pharmacokinetics of Cladribine in Patients with Multiple Sclerosis.

PubMed

Savic, Radojka M; Novakovic, Ana M; Ekblom, Marianne; Munafo, Alain; Karlsson, Mats O

2017-10-01

The aims of this study were to characterize the concentration-time course of cladribine (CdA) and its main metabolite 2-chloroadenine (CAde), estimate interindividual variability in pharmacokinetics (PK), and identify covariates explaining variability in the PK of CdA. This population PK analysis was based on the combined dataset from four clinical studies in patients with multiple sclerosis (MS): three phase I studies, including one food and one drug-drug interaction study, and one phase III clinical study. Plasma and urine concentration data of CdA and CAde were modeled simultaneously. The analysis comprised a total of 2619 CdA and CAde plasma and urine concentration observations from 173 patients with MS who received an intravenous infusion or oral tablet doses of CdA as a single agent or in combination with interferon (IFN) β-1a. CdA PK data were best described by a three-compartment model, while a one-compartment model best described the PK of CAde. CdA renal clearance (CL R ) was correlated with creatinine clearance (CL CR ), predicting a decrease in the total clearance of 19%, 30% and 40% for patients with mild (CL CR  = 65 ml/min), moderate (CL CR  = 40 ml/min) and severe (CL CR  = 20 ml/min) renal impairment, respectively. Food decreased the extent of CdA absorption by 11.2% and caused an absorption delay. Coadministration with IFNβ-1a was found to increase non-CL R (CL NR ) by 21%, resulting in an increase of 11% in total clearance. Both CdA and CAde displayed linear PK after intravenous and oral administration of CdA, with CdA renal function depending on CL CR . Trial registration number for study 25643: NCT00213135.

Comparison of pharmacokinetic variables for creatinine and iohexol in dogs with various degrees of renal function.

PubMed

Collignon, Cécile M; Heiene, Reidun; Queau, Yann; Reynolds, Brice S; Craig, Amanda J; Concordet, Didier; Harran, Nathaniel X; Risøen, Unni; Balouka, David; Faucher, Mathieu R; Eliassen, Knut A; Biourge, Vincent; Lefebvre, Hervé P

2012-11-01

To compare pharmacokinetics and clearances of creatinine and iohexol as estimates of glomerular filtration rate (GFR) in dogs with various degrees of renal function. 50 Great Anglo-Francais Tricolor Hounds with various degrees of renal function. Boluses of iohexol (40 mg/kg) and creatinine (647 mg/kg) were injected IV. Blood samples were collected before administration and 5 and 10 minutes and 1, 2, 4, 6, and 8 hours after administration. Plasma creatinine and iohexol concentrations were assayed via an enzymatic method and high-performance liquid chromatography, respectively. A noncompartmental approach was used for pharmacokinetic analysis. Pharmacokinetic variables were compared via a Bland-Altman plot and an ANOVA. Compared with results for creatinine, iohexol had a significantly higher mean ± SD plasma clearance (3.4 ± 0.8 mL/min/kg vs 3.0 ± 0.7 mL/min/kg) and a significantly lower mean volume of distribution at steady state (250 ± 37 mL/kg vs 539 ± 73 mL/kg), mean residence time (80 ± 31 minutes vs 195 ± 73 minutes), and mean elimination half-life (74 ± 20 minutes vs 173 ± 53 minutes). Despite discrepancies between clearances, especially for high values, the difference was < 0.6 mL/min/kg for 34 (68%) dogs. Three dogs with a low GFR (< 2 mL/min/kg) were classified similarly by both methods. Plasma iohexol and creatinine clearances can be used interchangeably for screening patients suspected of having chronic kidney disease (ie, low GFR), but large differences may exist for dogs with a GFR within or above the reference range.

Evaluation of Aztreonam Dosing Regimens in Patients With Normal and Impaired Renal Function: A Population Pharmacokinetic Modeling and Monte Carlo Simulation Analysis.

PubMed

Xu, Hongmei; Zhou, Wangda; Zhou, Diansong; Li, Jianguo; Al-Huniti, Nidal

2017-03-01

Aztreonam is a monocyclic β-lactam antibiotic often used to treat infections caused by Enterobacteriaceae or Pseudomonas aeruginosa. Despite the long history of clinical use, population pharmacokinetic modeling of aztreonam in renally impaired patients is not yet available. The aims of this study were to assess the impact of renal impairment on aztreonam exposure and to evaluate dosing regimens for patients with renal impairment. A population model describing aztreonam pharmacokinetics following intravenous administration was developed using plasma concentrations from 42 healthy volunteers and renally impaired patients from 2 clinical studies. The final pharmacokinetic model was used to predict aztreonam plasma concentrations and evaluate the probability of pharmacodynamic target attainment (PTA) in patients with different levels of renal function. A 2-compartment model with first-order elimination adequately described aztreonam pharmacokinetics. The population mean estimates of aztreonam clearance, intercompartmental clearance, volume of distribution of the central compartment, and volume of distribution of the peripheral compartment were 4.93 L/h, 9.26 L/h, 7.43 L, and 6.44 L, respectively. Creatinine clearance and body weight were the most significant variables to explain patient variability in aztreonam clearance and volume of distribution, respectively. Simulations using the final pharmacokinetic model resulted in a clinical susceptibility break point of 4 and 8 mg/L, respectively, based on the clinical use of 1- and 2-g loading doses with the same or reduced maintenance dose every 8 hours for various renal deficiency patients. The population pharmacokinetic modeling and PTA estimation support adequate PTAs (>90% PTA) from the aztreonam label for dose adjustment of aztreonam in patients with moderate and severe renal impairment. © 2016, The American College of Clinical Pharmacology.

Population Pharmacokinetic Analysis of Isoniazid, Acetylisoniazid, and Isonicotinic Acid in Healthy Volunteers

PubMed Central

Seng, Kok-Yong; Hee, Kim-Hor; Soon, Gaik-Hong; Chew, Nicholas; Khoo, Saye H.

2015-01-01

In this study, we aimed to quantify the effects of the N-acetyltransferase 2 (NAT2) phenotype on isoniazid (INH) metabolism in vivo and identify other sources of pharmacokinetic variability following single-dose administration in healthy Asian adults. The concentrations of INH and its metabolites acetylisoniazid (AcINH) and isonicotinic acid (INA) in plasma were evaluated in 33 healthy Asians who were also given efavirenz and rifampin. The pharmacokinetics of INH, AcINH, and INA were analyzed using nonlinear mixed-effects modeling (NONMEM) to estimate the population pharmacokinetic parameters and evaluate the relationships between the parameters and the elimination status (fast, intermediate, and slow acetylators), demographic status, and measures of renal and hepatic function. A two-compartment model with first-order absorption best described the INH pharmacokinetics. AcINH and INA data were best described by a two- and a one-compartment model, respectively, linked to the INH model. In the final model for INH, the derived metabolic phenotypes for NAT2 were identified as a significant covariate in the INH clearance, reducing its interindividual variability from 86% to 14%. The INH clearance in fast eliminators was 1.9- and 7.7-fold higher than in intermediate and slow eliminators, respectively (65 versus 35 and 8 liters/h). Creatinine clearance was confirmed as a significant covariate for AcINH clearance. Simulations suggested that the current dosing guidelines (200 mg for 30 to 45 kg and 300 mg for >45 kg) may be suboptimal (3 mg/liter ≤ Cmax ≤ 6 mg/liter) irrespective of the acetylator class. The analysis established a model that adequately characterizes INH, AcINH, and INA pharmacokinetics in healthy Asians. Our results refine the NAT2 phenotype-based predictions of the pharmacokinetics for INH. PMID:26282412

Flow Instability and Flow Control Scaling Laws

NASA Astrophysics Data System (ADS)

van Ness, Daniel; Corke, Thomas; Morris, Scott

2006-11-01

A flow instability that is receptive to perturbations is present in the tip clearance leakage flow over the tip of a turbine blade. This instability was investigated through the introduction of active flow control in the viscous flow field. Control was implemented in the form of a dielectric barrier discharge created by a weakly-ionized plasma actuation arrangement. The experimental setup consisted of a low-speed linear turbine cascade made up of an array of nine Pratt & Whitney ``PakB'' turbine blades. This idealized cascade configuration was used to examine the tip clearance leakage flow that exists within the low pressure turbine stage of a gas-turbine engine. The center blade of the cascade array had a variable tip clearance up to five percent chord. Reynolds numbers based on axial blade chord varied from 10^4 to 10^5. Multi-port pressure probe measurements, as well as Stereo Particle Image Velocimetry were used to document the dependence of the instability on the frequency and amplitude of flow control perturbations. Scaling laws based on the variation of blade tip clearance height and inflow conditions were investigated. These results permitted an improved understanding of the mechanism of flow instability.

The effects of pin elasticity, clearance, and friction on the stresses in a pin-loaded orthotropic plate

NASA Technical Reports Server (NTRS)

Hyer, M. W.; Klang, E. C.; Cooper, D. E.

1987-01-01

The effects of pin elasticity, clearance, and friction on the stresses in a pin loaded orthotropic plate are studied. The effects are studied by posing the problem as a planar contact elasticity problem, the pin and the plate being two elastic bodies which interact through contact. Coulomb friction is assumed, the pin loads the plate in one of its principal material directions, and the plate is infinite in extent. A collocation scheme and interaction, in conjunction with a complex variable series solution, are used to obtain numerical results. The contact region between the plate and pin is unknown and must be solved for as part of the solution. The same is true of the region of friction induced no slip. Two pin stiffnesses, two clearance levels, two friction levels and two laminates, a (0/+ or - 45/90)s and a (02/+ or - 45)s, are studied. The effects of pin elasticity, clearance, and friction on the load capacity of the plate are assessed by comparing the load capacity of the plate with the capacity when the pin is rigid, perfectly fitting, and frictionless.

Psychiatric and substance use disorders in HIV/hepatitis C virus (HCV)-coinfected patients: does HCV clearance matter? [Agence Nationale de Recherche sur le SIDA et les Hépatites Virales (ANRS) HEPAVIH CO13 cohort].

PubMed

Michel, L; Lions, C; Winnock, M; Lang, J-P; Loko, M-A; Rosenthal, E; Marchou, B; Valantin, M-A; Morlat, P; Roux, P; Sogni, P; Spire, B; Poizot-Martin, I; Lacombe, K; Lascoux-Combe, C; Duvivier, C; Neau, D; Dabis, F; Salmon-Ceron, D; Carrieri, M P

2016-11-01

The objective of this nested study was to assess the prevalence of psychiatric disorders in a sample of HIV/hepatitis C virus (HCV)-coinfected patients according to their HCV status. The nested cross-sectional study, untitled HEPAVIH-Psy survey, was performed in a subset of HIV/HCV-coinfected patients enrolled in the French Agence Nationale de Recherche sur le SIDA et les Hépatites Virales (ANRS) CO13 HEPAVIH cohort. Psychiatric disorders were screened for using the Mini International Neuropsychiatric Interview (MINI 5.0.0). Among the 286 patients enrolled in the study, 68 (24%) had never received HCV treatment, 87 (30%) were treatment nonresponders, 44 (15%) were currently being treated and 87 (30%) had a sustained virological response (SVR). Of the 286 patients enrolled, 121 patients (42%) screened positive for a psychiatric disorder other than suicidality and alcohol/drug abuse/dependence, 40 (14%) screened positive for alcohol abuse/dependence, 50 (18%) screened positive for drug abuse/dependence, 50 (17.5%) were receiving an antidepressant treatment and 69 (24%) were receiving an anxiolytic. Patients with an SVR did not significantly differ from the other groups in terms of psychiatric disorders. Patients receiving HCV treatment screened positive less often for an anxiety disorder. The highest rate of drug dependence/abuse was among HCV treatment-naïve patients. Psychiatric disorders were frequent in HIV/HCV-coinfected patients and their rates were comparable between groups, even for patients achieving an SVR. Our results emphasize the need for continuous assessment and care of coinfected patients, even after HCV clearance. Drug addiction remains an obstacle to access to HCV treatment. Despite the recent advent and continued development of directly acting antiviral agents (DAAs), it is still crucial to offer screening and comprehensive care for psychiatric and addictive disorders. © 2016 British HIV Association.

Carrageenan nasal spray in virus confirmed common cold: individual patient data analysis of two randomized controlled trials.

PubMed

Koenighofer, Martin; Lion, Thomas; Bodenteich, Angelika; Prieschl-Grassauer, Eva; Grassauer, Andreas; Unger, Hermann; Mueller, Christian A; Fazekas, Tamás

2014-01-01

Clinical trials applying iota-carrageenan nasal spray have previously shown to reduce duration of virus-confirmed common cold. The present study pooled data of two similar clinical trials to provide further evidence for the antiviral effectiveness of carrageenan. Individual patient data were analyzed from two randomized double blind placebo controlled trials assessing the therapeutic effectiveness of carrageenan nasal spray in acute common cold. Patients with virus-confirmed common cold (n = 254, verum 126, placebo 128) were included and the following parameters were appraised: duration of disease, number of patients with relapses, number of respiratory viruses and viral titers at inclusion (visit 1) compared to days 3-5 (visit 2). Carrageenan treated patients showed a significant reduction in duration of disease of almost 2 days (p < 0.05) as well as significantly fewer relapses during 21 days of observation period (p < 0.05). The virus clearance between visit 1 and visit 2 was significantly more pronounced in the carrageenan group (p < 0.05). In both studies, virus-confirmed common cold was caused by three main virus subtypes: human rhinovirus (46%), human coronavirus (25%) and influenza A (14%) virus. Carrageenan nasal spray showed significant antiviral efficacy in all three virus subgroups, the highest effectiveness was observed in human corona virus-infected patients. The reduced duration of disease was 3 days (p < 0.01) and the number of relapses was three times less (p < 0.01) in carrageenan treated corona-virus-infected patients compared to control patients. Administration of carrageenan nasal spray in children as well as in adults suffering from virus-confirmed common cold reduced duration of disease, increased viral clearance and reduced relapses of symptoms. Carrageenan nasal spray appeared as an effective treatment of common cold in children and adults. Pooled data from ISRCTN52519535 and ISRCTN80148028.

Association between Leptin and Complement in Hepatitis C Patients with Viral Clearance: Homeostasis of Metabolism and Immunity.

PubMed

Chang, Ming-Ling; Kuo, Chia-Jung; Huang, Hsin-Chih; Chu, Yin-Yi; Chiu, Cheng-Tang

2016-01-01

The association between leptin and complement in hepatitis C virus (HCV) infection remains unknown. A prospective study was conducted including 474 (250 genotype 1, 224 genotype 2) consecutive chronic hepatitis C (CHC) patients who had completed an anti-HCV therapy course and undergone pre-therapy and 24-week post-therapy assessments of interferon λ3-rs12979860 and HCV RNA/genotypes, anthropometric measurements, metabolic and liver profiles, and complement component 3 (C3), C4, and leptin levels. Of the 474 patients, 395 had a sustained virological response (SVR). Pre-therapy leptin levels did not differ between patients with and without an SVR. Univariate and multivariate analyses showed that sex (pre- and post-therapy, p<0.001), body mass index (BMI) (pre- and post-therapy, p<0.001), and C3 levels (pre-therapy, p = 0.027; post-therapy, p = 0.02) were independently associated with leptin levels with or without HCV infection. Pre-therapy BMI, total cholesterol (TC), C4 levels, and the rs12979860 genotype were independently associated with pre-therapy C3 levels in all patients. Post-therapy BMI, alanine aminotransferase, TC, C4 levels, white blood cell counts, and hepatic steatosis were independently associated with the post-therapy C3 levels of SVR patients. Compared with pre-therapy levels, SVR patients showed higher 24-week post-therapy C4 (20.32+/-7.30 vs. 21.55+/-7.07 mg/dL, p<0.001) and TC (171.68+/-32.67 vs. 186.97+/-36.09 mg/dL, p<0.001) levels; however, leptin and C3 levels remained unchanged after therapy in patients with and without an SVR. Leptin and C3 may maintain immune and metabolic homeostasis through association with C4 and TC. Positive alterations in C4 and TC levels reflect viral clearance after therapy in CHC patients.

Susceptibility of ocean- and stream-type Chinook salmon to isolates of the L, U, and M genogroups of infectious hematopoietic necrosis virus (IHNV)

USGS Publications Warehouse

Hernandez, Daniel; Purcell, Maureen K.; Friedman, Carolyn S.; Kurath, Gael

2016-01-01

This study examined the susceptibility of Chinook salmon Oncorhynchus tshawytscha to viral strains from the L, U, and M genogroups of infectious hematopoietic necrosis virus (IHNV) present in western North America. The goal of this investigation was to establish a baseline understanding of the susceptibility of ocean- and stream-type Chinook salmon to infection and mortality caused by exposure to commonly detected strains of L, U, and M IHNV. The L IHNV strain tested here was highly infectious and virulent in both Chinook salmon populations, following patterns previously reported for Chinook salmon. Furthermore, ocean- and stream-type Chinook salmon fry at 1 g can also become subclinically infected with U and M strains of IHNV without experiencing significant mortality. The stream-type life history phenotype was generally more susceptible to infection and suffered greater mortality than the ocean-type phenotype. Between the U and M genogroup strains tested, the U group strains were generally more infectious than the M group strains in both Chinook salmon types. Substantial viral clearance occurred by 30 d post exposure, but persistent viral infection was observed with L, U, and M strains in both host populations. While mortality decreased with increased host size in stream-type Chinook salmon, infection prevalence was not lower for all strains at a greater size. These results suggest that Chinook salmon may serve as reservoirs and/or vectors of U and M genogroup IHNV.

Blocking of PDL-1 interaction enhances primary and secondary CD8 T cell response to herpes simplex virus-1 infection.

PubMed

Channappanavar, Rudragouda; Twardy, Brandon S; Suvas, Susmit

2012-01-01

The blocking of programmed death ligand-1 (PDL-1) has been shown to enhance virus-specific CD8 T cell function during chronic viral infections. Though, how PDL-1 blocking at the time of priming affects the quality of CD8 T cell response to acute infections is not well understood and remains controversial. This report demonstrates that the magnitude of the primary and secondary CD8 T cell responses to herpes simplex virus-1 (HSV-1) infection is subject to control by PDL-1. Our results showed that after footpad HSV-1 infection, PD-1 expression increases on immunodominant SSIEFARL peptide specific CD8 T cells. Additionally, post-infection, the level of PDL-1 expression also increases on CD11c+ dendritic cells. Intraperitoneal administration of anti-PDL-1 monoclonal antibody given one day prior to and three days after cutaneous HSV-1 infection, resulted in a marked increase in effector and memory CD8 T cell response to SSIEFARL peptide. This was shown by measuring the quantity and quality of SSIEFARL-specific CD8 T cells by making use of ex-vivo assays that determine antigen specific CD8 T cell function, such as intracellular cytokine assay, degranulation assay to measure cytotoxicity and viral clearance. Our results are discussed in terms of the beneficial effects of blocking PDL-1 interactions, while giving prophylactic vaccines, to generate a more effective CD8 T cell response to viral infection.

Hepatitis B virus core antigen determines viral persistence in a C57BL/6 mouse model.

PubMed

Lin, Yi-Jiun; Huang, Li-Rung; Yang, Hung-Chih; Tzeng, Horng-Tay; Hsu, Ping-Ning; Wu, Hui-Lin; Chen, Pei-Jer; Chen, Ding-Shinn

2010-05-18

We recently developed a mouse model of hepatitis B virus (HBV) persistence, in which a single i.v. hydrodynamic injection of HBV DNA to C57BL/6 mice allows HBV replication and induces a partial immune response, so that about 20-30% of the mice carry HBV for more than 6 months. The model was used to identify the viral antigen crucial for HBV persistence. We knocked out individual HBV genes by introducing a premature termination codon to the HBV core, HBeAg, HBx, and polymerase ORFs. The specific-gene-deficient HBV mutants were hydrodynamically injected into mice and the HBV profiles of the mice were monitored. About 90% of the mice that received the HBcAg-mutated HBV plasmid exhibited high levels of hepatitis B surface antigenemia and maintained HBsAg expression for more than 6 months after injection. To map the region of HBcAg essential for viral clearance, we constructed a set of serial HBcAg deletion mutants for hydrodynamic injection. We localized the essential region of HBcAg to the carboxyl terminus, specifically to the 10 terminal amino acids (HBcAg176-185). The majority of mice receiving this HBV mutant DNA did not elicit a proper HBcAg-specific IFN-gamma response and expressed HBV virions for 6 months. These results indicate that the immune response triggered in mice by HBcAg during exposure to HBV is important in determining HBV persistence.

Arabidopsis DRB4, AGO1, AGO7, and RDR6 participate in a DCL4-initiated antiviral RNA silencing pathway negatively regulated by DCL1.

PubMed

Qu, Feng; Ye, Xiaohong; Morris, T Jack

2008-09-23

Plant RNA silencing machinery enlists four primary classes of proteins to achieve sequence-specific regulation of gene expression and mount an antiviral defense. These include Dicer-like ribonucleases (DCLs), Argonaute proteins (AGOs), dsRNA-binding proteins (DRBs), and RNA-dependent RNA polymerases (RDRs). Although at least four distinct endogenous RNA silencing pathways have been thoroughly characterized, a detailed understanding of the antiviral RNA silencing pathway is just emerging. In this report, we have examined the role of four DCLs, two AGOs, one DRB, and one RDR in controlling viral RNA accumulation in infected Arabidopsis plants by using a mutant virus lacking its silencing suppressor. Our results show that all four DCLs contribute to antiviral RNA silencing. We confirm previous reports implicating both DCL4 and DCL2 in this process and establish a minor role for DCL3. Surprisingly, we found that DCL1 represses antiviral RNA silencing through negatively regulating the expression of DCL4 and DCL3. We also implicate DRB4 in antiviral RNA silencing. Finally, we show that both AGO1 and AGO7 function to ensure efficient clearance of viral RNAs and establish that AGO1 is capable of targeting viral RNAs with more compact structures, whereas AGO7 and RDR6 favor less structured RNA targets. Our results resolve several key steps in the antiviral RNA silencing pathway and provide a basis for further in-depth analysis.

Susceptibility of ocean- and stream-type Chinook salmon to isolates of the L, U, and M genogroups of infectious hematopoietic necrosis virus (IHNV).

PubMed

Hernandez, Daniel G; Purcell, Maureen K; Friedman, Carolyn S; Kurath, Gael

2016-08-31

This study examined the susceptibility of Chinook salmon Oncorhynchus tshawytscha to viral strains from the L, U, and M genogroups of infectious hematopoietic necrosis virus (IHNV) present in western North America. The goal of this investigation was to establish a baseline understanding of the susceptibility of ocean- and stream-type Chinook salmon to infection and mortality caused by exposure to commonly detected strains of L, U, and M IHNV. The L IHNV strain tested here was highly infectious and virulent in both Chinook salmon populations, following patterns previously reported for Chinook salmon. Furthermore, ocean- and stream-type Chinook salmon fry at 1 g can also become subclinically infected with U and M strains of IHNV without experiencing significant mortality. The stream-type life history phenotype was generally more susceptible to infection and suffered greater mortality than the ocean-type phenotype. Between the U and M genogroup strains tested, the U group strains were generally more infectious than the M group strains in both Chinook salmon types. Substantial viral clearance occurred by 30 d post exposure, but persistent viral infection was observed with L, U, and M strains in both host populations. While mortality decreased with increased host size in stream-type Chinook salmon, infection prevalence was not lower for all strains at a greater size. These results suggest that Chinook salmon may serve as reservoirs and/or vectors of U and M genogroup IHNV.

Zika Virus Infection in Dexamethasone-immunosuppressed Mice Demonstrating Disseminated Infection with Multi-organ Involvement Including Orchitis Effectively Treated by Recombinant Type I Interferons.

PubMed

Chan, Jasper Fuk-Woo; Zhang, Anna Jinxia; Chan, Chris Chung-Sing; Yip, Cyril Chik-Yan; Mak, Winger Wing-Nga; Zhu, Houshun; Poon, Vincent Kwok-Man; Tee, Kah-Meng; Zhu, Zheng; Cai, Jian-Piao; Tsang, Jessica Oi-Ling; Chik, Kenn Ka-Heng; Yin, Feifei; Chan, Kwok-Hung; Kok, Kin-Hang; Jin, Dong-Yan; Au-Yeung, Rex Kwok-Him; Yuen, Kwok-Yung

2016-12-01

Disseminated or fatal Zika virus (ZIKV) infections were reported in immunosuppressed patients. Existing interferon-signaling/receptor-deficient mouse models may not be suitable for evaluating treatment effects of recombinant interferons. We developed a novel mouse model for ZIKV infection by immunosuppressing BALB/c mice with dexamethasone. Dexamethasone-immunosuppressed male mice (6-8weeks) developed disseminated infection as evidenced by the detection of ZIKV-NS1 protein expression and high viral loads in multiple organs. They had ≥10% weight loss and high clinical scores soon after dexamethasone withdrawal (10dpi), which warranted euthanasia at 12dpi. Viral loads in blood and most tissues at 5dpi were significantly higher than those at 12dpi (P<0.05). Histological examination revealed prominent inflammatory infiltrates in multiple organs, and CD45+ and CD8+ inflammatory cells were seen in the testis. These findings suggested that clinical deterioration occurred during viral clearance by host immune response. Type I interferon treatments improved clinical outcome of mice (100% vs 0% survival). Besides virus dissemination, inflammation of various tissues, especially orchitis, may be potential complications of ZIKV infection with significant implications on disease transmission and male fertility. Interferon treatment should be considered in patients at high risks for ZIKV-associated complications when the potential benefits outweigh the side effects of treatment. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Virion Glycoprotein-Mediated Immune Evasion by Human Cytomegalovirus: a Sticky Virus Makes a Slick Getaway

PubMed Central

Gardner, Thomas J.

2016-01-01

SUMMARY The prototypic herpesvirus human cytomegalovirus (CMV) exhibits the extraordinary ability to establish latency and maintain a chronic infection throughout the life of its human host. This is even more remarkable considering the robust adaptive immune response elicited by infection and reactivation from latency. In addition to the ability of CMV to exist in a quiescent latent state, its persistence is enabled by a large repertoire of viral proteins that subvert immune defense mechanisms, such as NK cell activation and major histocompatibility complex antigen presentation, within the cell. However, dissemination outside the cell presents a unique existential challenge to the CMV virion, which is studded with antigenic glycoprotein complexes targeted by a potent neutralizing antibody response. The CMV virion envelope proteins, which are critical mediators of cell attachment and entry, possess various characteristics that can mitigate the humoral immune response and prevent viral clearance. Here we review the CMV glycoprotein complexes crucial for cell attachment and entry and propose inherent properties of these proteins involved in evading the CMV humoral immune response. These include viral glycoprotein polymorphism, epitope competition, Fc receptor-mediated endocytosis, glycan shielding, and cell-to-cell spread. The consequences of CMV virion glycoprotein-mediated immune evasion have a major impact on persistence of the virus in the population, and a comprehensive understanding of these evasion strategies will assist in designing effective CMV biologics and vaccines to limit CMV-associated disease. PMID:27307580

Early IL-6 signalling promotes IL-27 dependent maturation of regulatory T cells in the lungs and resolution of viral immunopathology.

PubMed

Pyle, Chloe J; Uwadiae, Faith I; Swieboda, David P; Harker, James A

2017-09-01

Interleukin-6 is a pleiotropic, pro-inflammatory cytokine that can promote both innate and adaptive immune responses. In humans with respiratory virus infections, such as Respiratory Syncytial Virus (RSV), elevated concentrations of IL-6 are associated with more severe disease. In contrast the polymorphisms in the Il6 promoter which favour lower IL-6 production are associated with increased risk of both RSV and Rhinovirus infections. To determine the precise contribution of IL-6 to protection and pathology we used murine models of respiratory virus infection. RSV infection resulted in increased IL-6 production both in the airways and systemically which remained heightened for at least 2 weeks. IL-6 depletion early, but not late, during RSV or Influenza A virus infection resulted in significantly increased disease associated with an influx of virus specific TH1 and cytotoxic CD8+ T cells, whilst not affecting viral clearance. IL-6 acted by driving production of the immunoregulatory cytokine IL-27 by macrophages and monocytes, which in turn promoted the local maturation of regulatory T cells. Concordantly IL-27 was necessary to regulate TH1 responses in the lungs, and sufficient to limit RSV induced disease. Overall we found that during respiratory virus infection the prototypic inflammatory cytokine IL-6 is a critical anti-inflammatory regulator of viral induced immunopathology in the respiratory tract through its induction of IL-27.

Early IL-6 signalling promotes IL-27 dependent maturation of regulatory T cells in the lungs and resolution of viral immunopathology

PubMed Central

Swieboda, David P.

2017-01-01

Interleukin-6 is a pleiotropic, pro-inflammatory cytokine that can promote both innate and adaptive immune responses. In humans with respiratory virus infections, such as Respiratory Syncytial Virus (RSV), elevated concentrations of IL-6 are associated with more severe disease. In contrast the polymorphisms in the Il6 promoter which favour lower IL-6 production are associated with increased risk of both RSV and Rhinovirus infections. To determine the precise contribution of IL-6 to protection and pathology we used murine models of respiratory virus infection. RSV infection resulted in increased IL-6 production both in the airways and systemically which remained heightened for at least 2 weeks. IL-6 depletion early, but not late, during RSV or Influenza A virus infection resulted in significantly increased disease associated with an influx of virus specific TH1 and cytotoxic CD8+ T cells, whilst not affecting viral clearance. IL-6 acted by driving production of the immunoregulatory cytokine IL-27 by macrophages and monocytes, which in turn promoted the local maturation of regulatory T cells. Concordantly IL-27 was necessary to regulate TH1 responses in the lungs, and sufficient to limit RSV induced disease. Overall we found that during respiratory virus infection the prototypic inflammatory cytokine IL-6 is a critical anti-inflammatory regulator of viral induced immunopathology in the respiratory tract through its induction of IL-27. PMID:28953978

The effects of a salicylate, ibuprofen, and naproxen on the disposition of methotrexate in patients with rheumatoid arthritis.

PubMed

Tracy, T S; Krohn, K; Jones, D R; Bradley, J D; Hall, S D; Brater, D C

1992-01-01

We have studied the pharmacokinetics of methotrexate in patients with rheumatoid arthritis concurrently treated with choline magnesium trisalicylate, ibuprofen, naproxen, or a non-NSAID analgesic (control treatment). The apparent systemic clearance of methotrexate was significantly reduced by all three treatments. Trisalicylate and ibuprofen both significantly reduced methotrexate renal clearance, but only the trisalicylate significantly displaced methotrexate from protein, increasing the fraction unbound by 28%. These data show that NSAIDs can affect the disposition of methotrexate, possibly increasing the potential for toxicity and necessitating dosage adjustments. However, large inter-subject variability precludes specific dosage recommendations.

Metabolic and anthropometric parameters contribute to ART-mediated CD4+ T cell recovery in HIV-1-infected individuals: an observational study

PubMed Central

2011-01-01

Background The degree of immune reconstitution achieved in response to suppressive ART is associated with baseline individual characteristics, such as pre-treatment CD4 count, levels of viral replication, cellular activation, choice of treatment regimen and gender. However, the combined effect of these variables on long-term CD4 recovery remains elusive, and no single variable predicts treatment response. We sought to determine if adiposity and molecules associated with lipid metabolism may affect the response to ART and the degree of subsequent immune reconstitution, and to assess their ability to predict CD4 recovery. Methods We studied a cohort of 69 (48 females and 21 males) HIV-infected, treatment-naïve South African subjects initiating antiretroviral treatment (d4T, 3Tc and lopinavir/ritonavir). We collected information at baseline and six months after viral suppression, assessing anthropometric parameters, dual energy X-ray absorptiometry and magnetic resonance imaging scans, serum-based clinical laboratory tests and whole blood-based flow cytometry, and determined their role in predicting the increase in CD4 count in response to ART. Results We present evidence that baseline CD4+ T cell count, viral load, CD8+ T cell activation (CD95 expression) and metabolic and anthropometric parameters linked to adiposity (LDL/HDL cholesterol ratio and waist/hip ratio) significantly contribute to variability in the extent of CD4 reconstitution (ΔCD4) after six months of continuous ART. Conclusions Our final model accounts for 44% of the variability in CD4+ T cell recovery in virally suppressed individuals, representing a workable predictive model of immune reconstitution. PMID:21801351

Rapid Multiplex PCR Assay To Identify Respiratory Viral Pathogens: Moving Forward Diagnosing The Common Cold

PubMed Central

Gordon, Sarah M; Elegino-Steffens, Diane U; Agee, Willie; Barnhill, Jason; Hsue, Gunther

2013-01-01

Upper respiratory tract infections (URIs) can be a serious burden to the healthcare system. The majority of URIs are viral in etiology, but definitive diagnosis can prove difficult due to frequently overlapping clinical presentations of viral and bacterial infections, and the variable sensitivity, and lengthy turn-around time of viral culture. We tested new automated nested multiplex PCR technology, the FilmArray® system, in the TAMC department of clinical investigations, to determine the feasibility of replacing the standard viral culture with a rapid turn-around system. We conducted a feasibility study using a single-blinded comparison study, comparing PCR results with archived viral culture results from a convenience sample of cryopreserved archived nasopharyngeal swabs from acutely ill ED patients who presented with complaints of URI symptoms. A total of 61 archived samples were processed. Viral culture had previously identified 31 positive specimens from these samples. The automated nested multiplex PCR detected 38 positive samples. In total, PCR was 94.5% concordant with the previously positive viral culture results. However, PCR was only 63.4% concordant with the negative viral culture results, owing to PCR detection of 11 additional viral pathogens not recovered on viral culture. The average time to process a sample was 75 minutes. We determined that an automated nested multiplex PCR is a feasible alternative to viral culture in an acute clinical setting. We were able to detect at least 94.5% as many viral pathogens as viral culture is able to identify, with a faster turn-around time. PMID:24052914

A proposed role for efflux transporters in the pathogenesis of hydrocephalus

PubMed Central

Krishnamurthy, Satish; Tichenor, Michael D.; Satish, Akhila G.; Lehmann, David B.

2014-01-01

Hydrocephalus is a common brain disorder that is treated only with surgery. The basis for surgical treatment rests on the circulation theory. However, clinical and experimental data to substantiate circulation theory have remained inconclusive. In brain tissue and in the ventricles, we see that osmotic gradients drive water diffusion in water-permeable tissue. As the osmolarity of ventricular CSF increases within the cerebral ventricles, water movement into the ventricles increases and causes hydrocephalus. Macromolecular clearance from the ventricles is a mechanism to establish the normal CSF osmolarity, and therefore ventricular volume. Efflux transporters, (p-glycoprotein), are located along the blood brain barrier and play an important role in the clearance of macromolecules (endobiotics and xenobiotics) from the brain to the blood. There is clinical and experimental data to show that macromolecules are cleared out of the brain in normal and hydrocephalic brains. This article summarizes the existing evidence to support the role of efflux transporters in the pathogenesis of hydrocephalus. The location of p-gp along the pathways of macromolecular clearance and the broad substrate specificity of this abundant transporter to a variety of different macromolecules are reviewed. Involvement of p-gp in the transport of amyloid beta in Alzheimer disease and its relation to normal pressure hydrocephalus is reviewed. Finally, individual variability of p-gp expression might explain the variability in the development of hydrocephalus following intraventricular hemorrhage. PMID:25165050

Comparing viral metagenomics methods using a highly multiplexed human viral pathogens reagent

PubMed Central

Li, Linlin; Deng, Xutao; Mee, Edward T.; Collot-Teixeira, Sophie; Anderson, Rob; Schepelmann, Silke; Minor, Philip D.; Delwart, Eric

2014-01-01

Unbiased metagenomic sequencing holds significant potential as a diagnostic tool for the simultaneous detection of any previously genetically described viral nucleic acids in clinical samples. Viral genome sequences can also inform on likely phenotypes including drug susceptibility or neutralization serotypes. In this study, different variables of the laboratory methods often used to generate viral metagenomics libraries on the efficiency of viral detection and virus genome coverage were compared. A biological reagent consisting of 25 different human RNA and DNA viral pathogens was used to estimate the effect of filtration and nuclease digestion, DNA/RNA extraction methods, pre-amplification and the use of different library preparation kits on the detection of viral nucleic acids. Filtration and nuclease treatment led to slight decreases in the percentage of viral sequence reads and number of viruses detected. For nucleic acid extractions silica spin columns improved viral sequence recovery relative to magnetic beads and Trizol extraction. Pre-amplification using random RT-PCR while generating more viral sequence reads resulted in detection of fewer viruses, more overlapping sequences, and lower genome coverage. The ScriptSeq library preparation method retrieved more viruses and a greater fraction of their genomes than the TruSeq and Nextera methods. Viral metagenomics sequencing was able to simultaneously detect up to 22 different viruses in the biological reagent analyzed including all those detected by qPCR. Further optimization will be required for the detection of viruses in biologically more complex samples such as tissues, blood, or feces. PMID:25497414

Variability in apoptotic response to poliovirus infection.

PubMed

Romanova, Lyudmila I; Belov, George A; Lidsky, Peter V; Tolskaya, Elena A; Kolesnikova, Marina S; Evstafieva, Alexandra G; Vartapetian, Andrey B; Egger, Denise; Bienz, Kurt; Agol, Vadim I

2005-01-20

In several cell types, poliovirus activates the apoptotic program, implementation of which is suppressed by viral antiapoptotic functions. In such cells, productive infection leads to a necrotic cytopathic effect (CPE), while abortive reproduction, associated with inadequate viral antiapoptotic functions, results in apoptosis. Here, we describe two other types of cell response to poliovirus infection. Murine L20B cells expressing human poliovirus receptor responded to the infection by both CPE and apoptosis concurrently. Interruption of productive infection decreased rather than increased the proportion of apoptotic cells. Productive infection was accompanied by the early efflux of cytochrome c from the mitochondria in a proportion of cells and by activation of DEVD-specific caspases. Inactivation of caspase-9 resulted in a marked, but incomplete, prevention of the apoptotic response of these cells to viral infection. Thus, the poliovirus-triggered apoptotic program in L20B cells was not completely suppressed by the viral antiapoptotic functions. In contrast, human rhabdomyosarcoma RD cells did not develop appreciable apoptosis during productive or abortive infection, exhibiting inefficient efflux of cytochrome c from mitochondria and no marked activation of DEVD-specific caspases. The cells were also refractory to several nonviral apoptosis inducers. Nevertheless, typical caspase-dependent signs of apoptosis in a proportion of RD cells were observed after cessation of viral reproduction. Such "late" apoptosis was also observed in productively infected HeLa cells. In addition, a tiny proportion of all studied cells were TUNEL positive even in the presence of a caspase inhibitor. Degradation of DNA in such cells appeared to be a postmortem phenomenon. Biological relevance of variable host responses to viral infection is discussed.

A systematic review of oral herpetic viral infections in cancer patients: commonly used outcome measures and interventions.

PubMed

Elad, Sharon; Ranna, Vinisha; Ariyawardana, Anura; Correa, Maria Elvira Pizzigatti; Tilly, Vanessa; Nair, Raj G; Rouleau, Tanya; Logan, Richard M; Pinto, Andres; Charette, Veronica; Saunders, Debbie P; Jensen, Siri Beier

2017-02-01

To review the literature for outcome measures for oral viral infections in cancer patients. A secondary aim was to update the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO) clinical practice guidelines for the management of oral viral infections in cancer patients. Databases were searched for articles published in the English language, 1981-2013. Studies that met the eligibility criteria were reviewed systematically. The data about the outcome measures were classified according to the aim of the study: prevention, treatment, or non-interventional. The results of interventional studies were compared to the 2010 MASCC/ISOO publication. Multiple clinical and laboratory tests were used to measure oral viral infections, with great variability between studies. Most of the studies were about Herpes Simplex Virus (HSV). The outcome measure that was most commonly used was the presence of HSV infection diagnosed based on a combination of suggestive clinical presentation with a positive laboratory result. HSV culture was the most commonly reported laboratory outcome measure. Acyclovir and valacyclovir were consistently reported to be efficacious in the management of oral herpetic infections. No new data on the quality of life and economic aspects was found. Considering the variability in outcome measures reported to assess oral herpetic infections the researcher should select carefully the appropriate measures based on the objective of the study. Acyclovir and valacyclovir are effective in the management of oral herpetic infections in patients receiving treatment for cancer. Studies on newer anti-viral drugs may be useful to address the issue of anti-viral resistance.

Pressure model of a four-way spool valve for simulating electrohydraulic control systems

NASA Technical Reports Server (NTRS)

Gebben, V. D.

1976-01-01

An equation that relates the pressure flow characteristics of hydraulic spool valves was developed. The dependent variable is valve output pressure, and the independent variables are spool position and flow. This causal form of equation is preferred in applications that simulate the effects of hydraulic line dynamics. Results from this equation are compared with those from the conventional valve equation, whose dependent variable is flow. A computer program of the valve equations includes spool stops, leakage spool clearances, and dead-zone characteristics of overlap spools.

Absorption and Clearance of Pharmaceutical Aerosols in the Human Nose: Development of a CFD Model.

PubMed

Rygg, Alex; Longest, P Worth

2016-10-01

The objective of this study was to develop a computational fluid dynamics (CFD) model to predict the deposition, dissolution, clearance, and absorption of pharmaceutical particles in the human nasal cavity. A three-dimensional nasal cavity geometry was converted to a surface-based model, providing an anatomically-accurate domain for the simulations. Particle deposition data from a commercial nasal spray product was mapped onto the surface model, and a mucus velocity field was calculated and validated with in vivo nasal clearance rates. A submodel for the dissolution of deposited particles was developed and validated based on comparisons to existing in vitro data for multiple pharmaceutical products. A parametric study was then performed to assess sensitivity of epithelial drug uptake to model conditions and assumptions. The particle displacement distance (depth) in the mucus layer had a modest effect on overall drug absorption, while the mucociliary clearance rate was found to be primarily responsible for drug uptake over the timescale of nasal clearance for the corticosteroid mometasone furoate (MF). The model revealed that drug deposition in the nasal vestibule (NV) could slowly be transported into the main passage (MP) and then absorbed through connection of the liquid layer in the NV and MP regions. As a result, high intersubject variability in cumulative uptake was predicted, depending on the length of time the NV dose was left undisturbed without blowing or wiping the nose. This study has developed, for the first time, a complete CFD model of nasal aerosol delivery from the point of spray formation through absorption at the respiratory epithelial surface. For the development and assessment of nasal aerosol products, this CFD-based in silico model provides a new option to complement existing in vitro nasal cast studies of deposition and in vivo imaging experiments of clearance.

Iohexol clearance is superior to creatinine-based renal function estimating equations in detecting short-term renal function decline in chronic heart failure

PubMed Central

Cvan Trobec, Katja; Kerec Kos, Mojca; von Haehling, Stephan; Anker, Stefan D.; Macdougall, Iain C.; Ponikowski, Piotr; Lainscak, Mitja

2015-01-01

Aim To compare the performance of iohexol plasma clearance and creatinine-based renal function estimating equations in monitoring longitudinal renal function changes in chronic heart failure (CHF) patients, and to assess the effects of body composition on the equation performance. Methods Iohexol plasma clearance was measured in 43 CHF patients at baseline and after at least 6 months. Simultaneously, renal function was estimated with five creatinine-based equations (four- and six-variable Modification of Diet in Renal Disease, Cockcroft-Gault, Cockcroft-Gault adjusted for lean body mass, Chronic Kidney Disease Epidemiology Collaboration equation) and body composition was assessed using bioimpedance and dual-energy x-ray absorptiometry. Results Over a median follow-up of 7.5 months (range 6-17 months), iohexol clearance significantly declined (52.8 vs 44.4 mL/[min ×1.73 m2], P = 0.001). This decline was significantly higher in patients receiving mineralocorticoid receptor antagonists at baseline (mean decline -22% of baseline value vs -3%, P = 0.037). Mean serum creatinine concentration did not change significantly during follow-up and no creatinine-based renal function estimating equation was able to detect the significant longitudinal decline of renal function determined by iohexol clearance. After accounting for body composition, the accuracy of the equations improved, but not their ability to detect renal function decline. Conclusions Renal function measured with iohexol plasma clearance showed relevant decline in CHF patients, particularly in those treated with mineralocorticoid receptor antagonists. None of the equations for renal function estimation was able to detect these changes. ClinicalTrials.gov registration number NCT01829880 PMID:26718759

Reliability of In Vitro Methods used to Measure Intrinsic Clearance of Hydrophobic Organic Chemicals by Rainbow Trout: Results of an International Ring Trial.

PubMed

Nichols, John; Fay, Kellie; Bernhard, Mary Jo; Bischof, Ina; Davis, John; Halder, Marlies; Hu, Jing; Johanning, Karla; Laue, Heike; Nabb, Diane; Schlechtriem, Christian; Segner, Helmut; Swintek, Joe; Weeks, John; Embry, Michelle

2018-05-14

In vitro assays are widely employed to obtain intrinsic clearance estimates used in toxicokinetic modeling efforts. However, the reliability of these methods is seldom reported. Here we describe the results of an international ring trial designed to evaluate two in vitro assays used to measure intrinsic clearance in rainbow trout. An important application of these assays is to predict the effect of biotransformation on chemical bioaccumulation. Six laboratories performed substrate depletion experiments with cyclohexyl salicylate, fenthion, 4-n-nonylphenol, deltamethrin, methoxychlor, and pyrene using cryopreserved hepatocytes and liver S9 fractions from trout. Variability within and among laboratories was characterized as the percent coefficient of variation (CV) in measured in vitro intrinsic clearance rates (CLIN VITRO, INT; ml/h/mg protein or 106 cells) for each chemical and test system. Mean intra-laboratory CVs for each test chemical averaged 18.9% for hepatocytes and 14.1% for S9 fractions, while inter-laboratory CVs (all chemicals and all tests) averaged 30.1% for hepatocytes and 22.4% for S9 fractions. When CLIN VITRO, INT values were extrapolated to in vivo intrinsic clearance estimates (CLIN VIVO,INT; L/d/kg fish), both assays yielded similar levels of activity (< 4-fold difference for all chemicals). Hepatic clearance rates (CLH; L/d/kg fish) calculated using data from both assays exhibited even better agreement. These findings show that both assays are highly reliable and suggest that either may be used to inform chemical bioaccumulation assessments for fish. This study highlights several issues related to the demonstration of assay reliability and may provide a template for evaluating other in vitro biotransformation assays.

Population pharmacokinetics of rifampicin, pyrazinamide and isoniazid in children with tuberculosis: in silico evaluation of currently recommended doses

PubMed Central

Zvada, Simbarashe P.; Denti, Paolo; Donald, Peter R.; Schaaf, H. Simon; Thee, Stephanie; Seddon, James A.; Seifart, Heiner I.; Smith, Peter J.; McIlleron, Helen M.; Simonsson, Ulrika S. H.

2014-01-01

Objectives To describe the population pharmacokinetics of rifampicin, pyrazinamide and isoniazid in children and evaluate the adequacy of steady-state exposures. Patients and methods We used previously published data for 76 South African children with tuberculosis to describe the population pharmacokinetics of rifampicin, pyrazinamide and isoniazid. Monte Carlo simulations were used to predict steady-state exposures in children following doses in fixed-dose combination tablets in accordance with the revised guidelines. Reference exposures were derived from an ethnically similar adult population with tuberculosis taking currently recommended doses. Results The final models included allometric scaling of clearance and volume of distribution using body weight. Maturation was included for clearance of isoniazid and clearance and absorption transit time of rifampicin. For a 2-year-old child weighing 12.5 kg, the estimated typical oral clearances of rifampicin and pyrazinamide were 8.15 and 1.08 L/h, respectively. Isoniazid typical oral clearance (adjusted for bioavailability) was predicted to be 4.44, 11.6 and 14.6 L/h for slow, intermediate and fast acetylators, respectively. Higher oral clearance values in intermediate and fast acetylators also resulted from 23% lower bioavailability compared with slow acetylators. Conclusions Simulations based on our models suggest that with the new WHO dosing guidelines and utilizing available paediatric fixed-dose combinations, children will receive adequate rifampicin exposures when compared with adults, but with a larger degree of variability. However, pyrazinamide and isoniazid exposures in many children will be lower than in adults. Further studies are needed to confirm these findings in children administered the revised dosages and to optimize pragmatic approaches to dosing. PMID:24486870

Hypoalbuminemia Is Significantly Associated with Increased Clearance Time of High Dose Methotrexate in Patients Being Treated for Lymphoma or Leukemia

PubMed Central

Reiss, Samantha; Buie, Larry; Adel, Nelly; Goldman, Debra A.; Devlin, Sean M.; Douer, Dan

2017-01-01

As a weak acid, methotrexate (MTX) is bound to serum albumin and has variable protein binding. The purpose of this study was to assess serum albumin’s relationship with MTX pharmacokinetics by comparing MTX clearance and toxicities between patients with normal serum albumin to those with hypoalbuminemia. This single-center retrospective study included adult patients with leukemia or lymphoma who received their first MTX at a dose ≥ 1 gram/m2. Hypoalbuminemia was defined as serum albumin ≤ 3.4 g/dL. MTX clearance was defined as the first documented time the MTX level ≤ 0.05 micromolar. Fisher’s Exact tests and Wilcoxon Rank Sum tests were used to examine differences in toxicities and Cox proportional hazards regression was used to assess relationship with time to clearance. Of 523 patients identified, 167 patients were evaluable. One hundred thirty five patients had normal serum albumin and 32 had hypoalbuminemia. Hypoalbuminemia was associated with a higher proportion of patients experiencing edema, ascites or pleural effusions (34% vs. 12% p=0.006) and the concomitant use of nephrotoxic agents (41% vs. 20% p=0.021). Hypoalbuminemia was associated with a significantly longer time to methotrexate clearance (median: 96 hours vs 72 hour p=0.004). In addition, patients with hypoalbuminemia had a higher proportion of hyperbilirubinemia and significantly longer hospitalization (median 14 days vs. 5 days p<0.001). In conclusion, hypoalbuminemia was associated with increased time to MTX clearance and increase length of hospitalization. High dose MTX is safe to administer in patients with low albumin levels, with appropriate leucovorin rescue and good supportive care. PMID:27542957

Impact of fraction unbound, CYP3A, and CYP2D6 in vivo activities, and other potential covariates to the clearance of tramadol enantiomers in patients with neuropathic pain.

PubMed

de Moraes, Natália V; Lauretti, Gabriela R; Coelho, Eduardo B; Godoy, Ana Leonor P C; Neves, Daniel V; Lanchote, Vera L

2016-04-01

The pharmacokinetics of tramadol is characterized by a large interindividual variability, which is partially attributed to polymorphic CYP2D6 metabolism. The contribution of CYP3A, CYP2B6, fraction unbound, and other potential covariates remains unknown. This study aimed to investigate the contribution of in vivo activities of cytochrome P450 (CYP) 2D6 and 3A as well as other potential covariates (CYP2B6 genotype to the SNP g.15631G>T, fraction unbound, age, body weight, creatinine clearance) to the enantioselective pharmacokinetics of tramadol. Thirty patients with neuropathic pain and phenotyped as CYP2D6 extensive metabolizers were treated with a single oral dose of 100 mg tramadol. Multiple linear regressions were performed to determine the contribution of CYP activities and other potential covariates to the clearance of tramadol enantiomers. The apparent total clearances were 44.9 (19.1-102-2) L/h and 55.2 (14.8-126.0) L/h for (+)- and (-)-tramadol, respectively [data presented as median (minimum-maximum)]. Between 79 and 83% of the overall variation in apparent clearance of tramadol enantiomers was explained by fraction unbound, CYP2D6, and CYP3A in vivo activities and body weight. Fraction unbound explained 47 and 41% of the variation in clearance of (+)-tramadol and (-)-tramadol, respectively. Individually, CYP2D6 and CYP3A activities were shown to have moderate contribution on clearance of tramadol enantiomers (11-16% and 11-18%, respectively). In conclusion, factors affecting fraction unbound of drugs (such as hyperglycemia or co-administration of drugs highly bound to plasma proteins) should be monitored, because this parameter dominates the elimination of tramadol enantiomers. © 2015 Société Française de Pharmacologie et de Thérapeutique.

Population pharmacokinetics of teicoplanin in hospitalized elderly patients using cystatin C as an indicator of renal function.

PubMed

Kasai, Hidefumi; Tsuji, Yasuhiro; Hiraki, Yoichi; Tsuruyama, Moeko; To, Hideto; Yamamoto, Yoshihiro

2018-04-01

Serum cystatin C (CysC) has recently been proposed as an alternative marker to serum creatinine (SCR) for estimating renal clearance. In the present study, we performed a population pharmacokinetic analysis of teicoplanin (TEIC), which is mainly eliminated through the kidneys, using CysC as a predictor for renal clearance. Thirty-six patients with MRSA infections who were administrated to the National Hospital Organization Beppu Medical Center between January 2012 and December 2013 were enrolled and gave 123 sets of blood TEIC concentration data. Renal clearance was estimated by the Hoek equation using CysC, by creatinine clearance predicted by the Cockcroft-Gault equation using SCR, or directly by CysC. One compartment open model with inter-individual variabilities for renal clearance and the volume of distribution as well as an additional residual error model was used to estimate population pharmacokinetic parameters for TEIC. The model with the best predictability was that with CysC as a predictor for renal clearance; it showed better significance than the models using estimated the glomerular filtration rate by the Hoek equation or CLcr. The final model was as follows: CL (L/hr) = 0.510 × (CysC/1.4) -0.68  × Total body weight/60 0.81 , omega (CL) = 19.8% CV, VC (L) = 78.1, omega (V) = 42.7% CV. The present results show the usefulness of CysC to more accurately predict the pharmacokinetics of drugs mainly eliminated through the kidneys, such as TEIC. However, since the sample size in this study was relatively small, further investigations on renal clearance predictability using CysC are needed. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Protective Role of Cytotoxic T Lymphocytes in Filovirus Hemorrhagic Fever

PubMed Central

Warfield, Kelly Lyn; Olinger, Gene Garrard

2011-01-01

Infection with many emerging viruses, such as the hemorrhagic fever disease caused by the filoviruses, Marburg (MARV), and Ebola virus (EBOV), leaves the host with a short timeframe in which to mouse a protective immune response. In lethal cases, uncontrolled viral replication and virus-induced immune dysregulation are too severe to overcome, and mortality is generally associated with a lack of notable immune responses. Vaccination studies in animals have demonstrated an association of IgG and neutralizing antibody responses against the protective glycoprotein antigen with survival from lethal challenge. More recently, studies in animal models of filovirus hemorrhagic fever have established that induction of a strong filovirus-specific cytotoxic T lymphocyte (CTL) response can facilitate complete viral clearance. In this review, we describe assays used to discover CTL responses after vaccination or live filovirus infection in both animal models and human clinical trials. Unfortunately, little data regarding CTL responses have been collected from infected human survivors, primarily due to the low frequency of disease and the inability to perform these studies in the field. Advancements in assays and technologies may allow these studies to occur during future outbreaks. PMID:22253531

Hepatitis C Virus Evasion Mechanisms from Neutralizing Antibodies

PubMed Central

Di Lorenzo, Caterina; Angus, Allan G. N.; Patel, Arvind H.

2011-01-01

Hepatitis C virus (HCV) represents a major public health problem, affecting 3% of the world’s population. The majority of infected individuals develop chronic hepatitis, which can progress to cirrhosis and hepatocellular carcinoma. To date, a vaccine is not available and current therapy is limited by resistance, adverse effects and high costs. Although it is very well established that cell-mediated immunity is necessary for viral clearance, the importance of host antibodies in clearing HCV infection is being increasingly recognized. Indeed, recent studies indicate that neutralizing antibodies are induced in the early phase of infection by patients who subsequently clear viral infection. Conversely, patients who do not clear the virus develop high titers of neutralizing antibodies during the chronic stage. Surprisingly, these antibodies are not able to control HCV infection. HCV has therefore developed mechanisms to evade immune elimination, allowing it to persist in the majority of infected individuals. A detailed understanding of the mechanisms by which the virus escapes immune surveillance is therefore necessary if novel preventive and therapeutic treatments have to be designed. This review summarizes the current knowledge of the mechanisms used by HCV to evade host neutralizing antibodies. PMID:22163345

Hepatitis B virus inhibits intrinsic RIG-I and RIG-G immune signaling via inducing miR146a

PubMed Central

Hou, Zhaohua; Zhang, Jian; Han, Qiuju; Su, Chenhe; Qu, Jing; Xu, Dongqing; Zhang, Cai; Tian, Zhigang

2016-01-01

Previous studies showed that hepatitis B virus (HBV), as a latency invader, attenuated host anti-viral immune responses. miRNAs were shown to be involved in HBV infection and HBV-related diseases, however, the precise role of miRNAs in HBV-mediated immunosuppression remains unclear. Here, we observed that down-regulated RIG-I like receptors might be one critical mechanism of HBV-induced suppression of type I IFN transcription in both HBV+ hepatoma cell lines and liver cancer tissues. Then, miR146a was demonstrated to negatively regulate the expression of RIG-I-like receptors by directly targeting both RIG-I and RIG-G. Further investigation showed that antagonizing miR146a by anti-sense inhibitors or sponge approach accelerated HBV clearance and reduced HBV load both in vitro and in a HBV-carrying mouse model. Therefore, our findings indicated that HBV-induced miR146a attenuates cell-intrinsic anti-viral innate immunity through targeting RIG-I and RIG-G, and silencing miR146a might be an effective target to reverse HBV-induced immune suppression. PMID:27210312

HIV antibodies for treatment of HIV infection

PubMed Central

Margolis, David M.; Koup, Richard A.; Ferrari, Guido

2016-01-01

Summary The bar is high to improve on current combination antiretroviral therapy (ART), now highly effective, safe, and simple. However antibodies that bind the HIV envelope are able to uniquely target the virus as it seeks to enter new target cells, or as it is expressed from previously infected cells. Further, the use of antibodies against HIV as a therapeutic may offer advantages. Antibodies can have long half-lives, and are being considered as partners for long-acting antiretrovirals for use in therapy or prevention of HIV infection. Early studies in animal models and in clinical trials suggest that such antibodies can have antiviral activity but, as with small molecule antiretrovirals, the issues of viral escape and resistance will have to be addressed. Most promising, however, are the unique properties of anti-HIV antibodies: the potential ability to opsonize viral particles, to direct antibody-dependent cellular cytotoxicity (ADCC) against actively infected cells, and ultimately the ability to direct the clearance of HIV-infected cells by effector cells of the immune system. These distinctive activities suggest that HIV antibodies and their derivatives may play an important role in the next frontier of HIV therapeutics, the effort to develop treatments that could lead to an HIV cure. PMID:28133794

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sigaud, Samuel; Goldsmith, Carroll-Ann W.; Zhou Hongwei

Epidemiological studies reveal increased incidence of lung infection when air pollution particle levels are increased. We postulate that one risk factor for bacterial pneumonia, prior viral infection, can prime the lung for greater deleterious effects of particles via the interferon-gamma (IFN-{gamma}) characteristic of successful host anti-viral responses. To test this postulate, we developed a mouse model in which mice were treated with {gamma}-interferon aerosol, followed by exposure to concentrated ambient particles (CAPs) collected from urban air. The mice were then infected with Streptococcus pneumoniae and the effect of these treatments on the lung's innate immune response was evaluated. The combinationmore » of IFN-{gamma} priming and CAPs exposure enhanced lung inflammation, manifest as increased polymorphonuclear granulocyte (PMN) recruitment to the lung, and elevated expression of pro-inflammatory cytokine mRNAs. Combined priming and CAPs exposure resulted in impaired pulmonary bacterial clearance, as well as increased oxidant production and diminished bacterial uptake by alveolar macrophages (AMs) and PMNs. The data suggest that priming and CAPs exposure lead to an inflamed alveolar milieu where oxidant stress causes loss of antibacterial functions in AMs and recruited PMNs. The model reported here will allow further analysis of priming and CAPs exposure on lung sensitivity to infection.« less

Memory B cells, but not long-lived plasma cells, possess antigen specificities for viral escape mutants

PubMed Central

Purtha, Whitney E.; Tedder, Thomas F.; Johnson, Syd

2011-01-01

Memory B cells (MBCs) and long-lived plasma cells (LLPCs) persist after clearance of infection, yet the specific and nonredundant role MBCs play in subsequent protection is unclear. After resolution of West Nile virus infection in mice, we demonstrate that LLPCs were specific for a single dominant neutralizing epitope, such that immune serum poorly inhibited a variant virus that encoded a mutation at this critical epitope. In contrast, a large fraction of MBC produced antibody that recognized both wild-type (WT) and mutant viral epitopes. Accordingly, antibody produced by the polyclonal pool of MBC neutralized WT and variant viruses equivalently. Remarkably, we also identified MBC clones that recognized the mutant epitope better than the WT protein, despite never having been exposed to the variant virus. The ability of MBCs to respond to variant viruses in vivo was confirmed by experiments in which MBCs were adoptively transferred or depleted before secondary challenge. Our data demonstrate that class-switched MBC can respond to variants of the original pathogen that escape neutralization of antibody produced by LLPC without a requirement for accumulating additional somatic mutations. PMID:22162833

The innate immunity of guinea pigs against highly pathogenic avian influenza virus infection

PubMed Central

Zhang, Kun; wei Xu, Wei; Zhang, Zhaowei; liu, Jing; Li, Jing; Sun, Lijuan; Sun, Weiyang; Jiao, Peirong; Sang, Xiaoyu; Ren, Zhiguang; Yu, Zhijun; Li, Yuanguo; Feng, Na; Wang, Tiecheng; Wang, Hualei; Yang, Songtao; Zhao, Yongkun; Zhang, Xuemei; Wilker, Peter R.; Liu, WenJun; Liao, Ming; Chen, Hualan; Gao, Yuwei; Xia, Xianzhu

2017-01-01

H5N1 avian influenza viruses are a major pandemic concern. In contrast to the highly virulent phenotype of H5N1 in humans and many animal models, guinea pigs do not typically display signs of severe disease in response to H5N1 virus infection. Here, proteomic and transcriptional profiling were applied to identify host factors that account for the observed attenuation of A/Tiger/Harbin/01/2002 (H5N1) virulence in guinea pigs. RIG-I and numerous interferon stimulated genes were among host proteins with altered expression in guinea pig lungs during H5N1 infection. Overexpression of RIG-I or the RIG-I adaptor protein MAVS in guinea pig cell lines inhibited H5N1 replication. Endogenous GBP-1 expression was required for RIG-I mediated inhibition of viral replication upstream of the activity of MAVS. Furthermore, we show that guinea pig complement is involved in viral clearance, the regulation of inflammation, and cellular apoptosis during influenza virus infection of guinea pigs. This work uncovers features of the guinea pig innate immune response to influenza that may render guinea pigs resistant to highly pathogenic influenza viruses. PMID:28418930

Morphine clearance in children: does race or genetics matter?

PubMed

Sadhasivam, Senthilkumar; Krekels, Elke H J; Chidambaran, Vidya; Esslinger, Hope R; Ngamprasertwong, Pornswan; Zhang, Kejian; Fukuda, Tsuyoshi; Vinks, Alexander A

2012-01-01

Interindividual variability in analgesic response and adverse effects of opioids because of narrow therapeutic indices are major clinical problems. Morphine is an opioid commonly used in children to manage perioperative pain. Al-though size and age often are considered primary covariates for morphine pharmacokinetic models, the impact of other factors important in personalizing care such as race and genetic variations on morphine disposition is not well documented. Genotype blinded clinical observational pharmacokinetic study. One hundred forty-six African American and Caucasian children scheduled for elective outpatient adenotonsillectomy were enrolled in our prospective genotype blinded observational study with standard perioperative clinical care. Tertiary care pediatric institution. Morphine bolus for intraoperative analgesia in children and pharmacokinetic analyses in different races. Pharmacokinetics and pharmacogenetics of intravenous morphine in a homogeneous pediatric outpatient surgical pain population were evaluated. The authors observed that African American children have higher morphine clearance than Caucasian children. The increased clearance is directed toward the formation of morphine-3-glucuronide formation, rather than the formation of morphine-6-glucuronide. Common uridine diphosphate glucuronosyl transferase (UGT) 2B7 genetic variations (2161C>T and 802C>T) were not associated with observed racial differences in morphine's clearance although the wild type of the UGT2B7 isozyme is more prevalent in the African Americans. Race of the child is an important factor in perioperative intravenous morphine's clearance and its potential role in personalizing analgesia with morphine needs further investigation.

Trends in detectable viral load by calendar year in the Australian HIV observational database.

PubMed

Law, Matthew G; Woolley, Ian; Templeton, David J; Roth, Norm; Chuah, John; Mulhall, Brian; Canavan, Peter; McManus, Hamish; Cooper, David A; Petoumenos, Kathy

2011-02-23

Recent papers have suggested that expanded combination antiretroviral treatment (cART) through lower viral load may be a strategy to reduce HIV transmission at a population level. We assessed calendar trends in detectable viral load in patients recruited to the Australian HIV Observational Database who were receiving cART. Patients were included in analyses if they had started cART (defined as three or more antiretrovirals) and had at least one viral load assessment after 1 January 1997. We analyzed detectable viral load (>400 copies/ml) in the first and second six months of each calendar year while receiving cART. Repeated measures logistic regression methods were used to account for within and between patient variability. Rates of detectable viral load were predicted allowing for patients lost to follow up. Analyses were based on 2439 patients and 31,339 viral load assessments between 1 January 1997 and 31 March 2009. Observed detectable viral load in patients receiving cART declined to 5.3% in the first half of 2009. Predicted detectable viral load based on multivariate models, allowing for patient loss to follow up, also declined over time, but at higher levels, to 13.8% in 2009. Predicted detectable viral load in Australian HIV Observational Database patients receiving cART declined over calendar time, albeit at higher levels than observed. However, over this period, HIV diagnoses and estimated HIV incidence increased in Australia.

Poly D,L-lactide-co-glycolide (PLGA) nanoparticle-encapsulated honeybee (Apis melifera) venom promotes clearance of Salmonella enterica serovar Typhimurium infection in experimentally challenged pigs through the up-regulation of T helper type 1 specific immune responses.

PubMed

Lee, Jin-A; Jung, Bock-Gie; Kim, Tae-Hoon; Kim, Yun-Mi; Park, Min-Ho; Hyun, Pung-mi; Jeon, Jong-woon; Park, Jin-kyu; Cho, Cheong-Weon; Suh, Guk-Hyun; Lee, Bong-Joo

2014-10-15

Honeybee (Apis melifera) venom (HBV), which includes melittin and lipid-soluble ingredients (chrysin and pinocembrin), elicited increases in the CD4(+)/CD8(+) T lymphocyte ratio, relative mRNA expression levels of the T helper type 1 (Th 1) cytokines (interferon-γ and IL-12) and reinforced viral clearance of an experimental porcine reproductive and respiratory syndrome (PRRS) virus infection in our previous study. On the basis of that previous study, we have now developed poly-d,l-lactide-co-glycolide (PLGA)-encapsulated HBV nanoparticles (P-HBV) for longer sustained release of HBV. We administered P-HBV to pigs via the rectal route, and then evaluated the potential immune-enhancing and bacterial clearance effects of P-HBV against Salmonella enterica serovar Typhimurium. The CD4(+)/CD8(+) lymphocyte ratio, proliferative capacity of peripheral blood lymphocytes and relative mRNA expression levels of IFN-γ and IL-12 (produced mainly by Th1 lymphocytes) were significantly increased in the P-HBV group up to 2 weeks post-administration of P-HBV. After S. Typhimurium infection, the P-HBV group showed a marked reduction in microbial burden in feces and all tissue samples (including the ileum, cecum, colon, and mesenteric lymph node (MLN)), a significant increase in Th 1 cytokines (IFN-γ, IL-2, and IL-12) and a marked decrease in a Th 2 cytokine (IL-4) in all tissue samples and peripheral blood lymphocytes. Thus, P-HBV may be a promising strategy for immune enhancement and prevention of S. Typhimurium or other bacterial infections. Copyright © 2014 Elsevier B.V. All rights reserved.

Immune clearance of highly pathogenic SIV infection

PubMed Central

Hansen, Scott G.; Piatak, Michael; Ventura, Abigail B.; Hughes, Colette M.; Gilbride, Roxanne M.; Ford, Julia C.; Oswald, Kelli; Shoemaker, Rebecca; Li, Yuan; Lewis, Matthew S.; Gilliam, Awbrey N.; Xu, Guangwu; Whizin, Nathan; Burwitz, Benjamin J.; Planer, Shannon L.; Turner, John M.; Legasse, Alfred W.; Axthelm, Michael K.; Nelson, Jay A.; Früh, Klaus; Sacha, Jonah B.; Estes, Jacob D.; Keele, Brandon F.; Edlefsen, Paul T.; Lifson, Jeffrey D.; Picker, Louis J.

2013-01-01

Established infections with the human and simian immunodeficiency viruses (HIV, SIV) are thought to be permanent with even the most effective immune responses and anti-retroviral therapies (ART) only able to control, but not clear, these infections1–4. Whether the residual virus that maintains these infections is vulnerable to clearance is a question of central importance to the future management of millions of HIV-infected individuals. We recently reported that ~50% of rhesus macaques (RM) vaccinated with SIV protein-expressing Rhesus Cytomegalovirus (RhCMV/SIV) vectors manifest durable, aviremic control of infection with highly pathogenic SIVmac2395. Here, we demonstrate that regardless of route of challenge, RhCMV/SIV vector-elicited immune responses control SIVmac239 after demonstrable lymphatic and hematogenous viral dissemination, and that replication-competent SIV persists in multiple sites for weeks to months. However, over time, protected RM lost signs of SIV infection, showing a consistent lack of measurable plasma or tissue-associated virus using ultrasensitive assays, and loss of T cell reactivity to SIV determinants not in the vaccine. Extensive ultrasensitive RT-PCR and PCR analysis of tissues from RhCMV/SIV vector-protected RM necropsied 69–172 weeks after challenge did not detect SIV RNA or DNA over background, and replication-competent SIV was not detected in these RM by extensive co-culture analysis of tissues or by adoptive transfer of 60 million hematolymphoid cells to naïve RM. These data provide compelling evidence for progressive clearance of a pathogenic lentiviral infection, and suggest that some lentiviral reservoirs may be susceptible to the continuous effector memory T cell-mediated immune surveillance elicited and maintained by CMV vectors. PMID:24025770

Immune clearance of highly pathogenic SIV infection.

PubMed

Hansen, Scott G; Piatak, Michael; Ventura, Abigail B; Hughes, Colette M; Gilbride, Roxanne M; Ford, Julia C; Oswald, Kelli; Shoemaker, Rebecca; Li, Yuan; Lewis, Matthew S; Gilliam, Awbrey N; Xu, Guangwu; Whizin, Nathan; Burwitz, Benjamin J; Planer, Shannon L; Turner, John M; Legasse, Alfred W; Axthelm, Michael K; Nelson, Jay A; Früh, Klaus; Sacha, Jonah B; Estes, Jacob D; Keele, Brandon F; Edlefsen, Paul T; Lifson, Jeffrey D; Picker, Louis J

2013-10-03

Established infections with the human and simian immunodeficiency viruses (HIV and SIV, respectively) are thought to be permanent with even the most effective immune responses and antiretroviral therapies only able to control, but not clear, these infections. Whether the residual virus that maintains these infections is vulnerable to clearance is a question of central importance to the future management of millions of HIV-infected individuals. We recently reported that approximately 50% of rhesus macaques (RM; Macaca mulatta) vaccinated with SIV protein-expressing rhesus cytomegalovirus (RhCMV/SIV) vectors manifest durable, aviraemic control of infection with the highly pathogenic strain SIVmac239 (ref. 5). Here we show that regardless of the route of challenge, RhCMV/SIV vector-elicited immune responses control SIVmac239 after demonstrable lymphatic and haematogenous viral dissemination, and that replication-competent SIV persists in several sites for weeks to months. Over time, however, protected RM lost signs of SIV infection, showing a consistent lack of measurable plasma- or tissue-associated virus using ultrasensitive assays, and a loss of T-cell reactivity to SIV determinants not in the vaccine. Extensive ultrasensitive quantitative PCR and quantitative PCR with reverse transcription analyses of tissues from RhCMV/SIV vector-protected RM necropsied 69-172 weeks after challenge did not detect SIV RNA or DNA sequences above background levels, and replication-competent SIV was not detected in these RM by extensive co-culture analysis of tissues or by adoptive transfer of 60 million haematolymphoid cells to naive RM. These data provide compelling evidence for progressive clearance of a pathogenic lentiviral infection, and suggest that some lentiviral reservoirs may be susceptible to the continuous effector memory T-cell-mediated immune surveillance elicited and maintained by cytomegalovirus vectors.

Hepatitis C virus reinfection incidence and treatment outcome among HIV-positive MSM.

PubMed

Martin, Thomas C S; Martin, Natasha K; Hickman, Matthew; Vickerman, Peter; Page, Emma E; Everett, Rhiannon; Gazzard, Brian G; Nelson, Mark

2013-10-23

Liver disease secondary to hepatitis C virus (HCV) infection in the context of HIV infection is one of the leading non-AIDS causes of death. Sexual transmission of HCV infection among HIV-positive MSM appears to be leading to increased reports of acute HCV infection. Reinfection after successful treatment or spontaneous clearance is reported among HIV-positive MSM but the scale of reinfection is unknown. We calculate and compare HCV reinfection rates among HIV-positive MSM after spontaneous clearance and successful medical treatment of infection. Retrospective analysis of HIV-positive MSM with sexually acquired HCV who subsequently spontaneously cleared or underwent successful HCV treatment between 2004 and 2012. Among 191 individuals infected with HCV, 44 were reinfected over 562 person-years (py) of follow-up with an overall reinfection rate of 7.8/100 py [95% confidence interval (CI) 5.8-10.5]. Eight individuals were subsequently reinfected a second time at a rate of 15.5/100 py (95% CI 7.7-31.0). Combining all reinfections, 20% resulted in spontaneous clearance and treatment sustained viral response rates were 73% (16/22) for genotypes one and four and 100% (2/2) for genotypes two and three. Among 145 individuals with a documented primary infection, the reinfection rate was 8.0 per 100 py (95% CI 5.7-11.3) overall, 9.6/100 py (95% CI 6.6-14.1) among those successfully treated and 4.2/100 py (95% CI 1.7-10.0) among those who spontaneously cleared. The secondary reinfection rate was 23.2/100 py (95% CI 11.6-46.4). Despite efforts at reducing risk behaviour, HIV-positive MSM who clear HCV infection remain at high risk of reinfection. This emphasizes the need for increased sexual education, surveillance and preventive intervention work.

Numerical analysis of the blade tip-timing signal of a fiber bundle sensor probe

NASA Astrophysics Data System (ADS)

Guo, Haotian; Duan, Fajie; Cheng, Zhonghai

2015-03-01

Blade tip-timing is the most effective method for online blade vibration measurement of large rotating machines like turbine engines. Fiber bundle sensors are utilized in tip-timing system to measure the arrival time of the blade. The model of the tip-timing signal of the fiber bundle sensor is established. Experiments are conducted and the results are in concordance with the model established. The rising speed of the tip-timing signal is analyzed. To minimize the tip-timing error, the effects of the clearance change between the sensor and the blade and the deflection of the tip surface are analyzed. Simulation results indicate that the variable gain amplifier, which amplifies the signals to a similar level, can eliminate the measurement error caused by the variation of the clearance between the sensor and blade. Increasing the clearance between the sensor and blade can reduce the measurement error introduced by deflection of the tip surface.

Theophylline kinetics in relation to age: the importance of smoking.

PubMed Central

Cusack, B; Kelly, J G; Lavan, J; Noel, J; O'Malley, K

1980-01-01

1 Single dose studies of theophylline kinetics were compared in groups of young and elderly smokers and non-smokers to assess the effect of age on theophylline absorption and the effect of smoking on drug metabolising enzyme activity in old age. 2 The rate and extent of absorption was not affected by age. Distribution and elimination kinetics were similar in young and elderly non-smokers. 3 In young subjects the elimination half-life of theophylline was shorter and clearance was significantly greater in smokers than in non-smokers. 4 In the elderly mean elimination half-life was significantly shorter in smokers and their plasma clearance was 40% higher than in non-smokers. The statistical difference for clearance was at the 7% level of significance. 5 These data indicate that ageing per se does not affect theophylline elimination and also that induction of theophylline metabolism due to smoking occurs in old age. Smoking is a variable that should be taken account of when assessing drug metabolism in elderly patients. PMID:7426272

A Non-oncogenic HPV 16 E6/E7 Vaccine Enhances Treatment of HPV Expressing Tumors

PubMed Central

Wieking, Bryant G.; Vermeer, Daniel W.; Spanos, William C.; Lee, Kimberly M.; Vermeer, Paola; Lee, Walter T.; Xu, Younong; Gabitzsch, Elizabeth S.; Balcaitis, Stephanie; Balint, Joseph P.; Jones, Frank R.; Lee, John H.

2012-01-01

Human papillomaviruses (HPVs) are the causative factor for greater than 90% of cervical cancers and 25% of head and neck cancers. The incidence of HPV positive (+) head and neck squamous cell carcinomas (HNSCCs) has greatly increased in the last 30 years. E6 and E7 are the two key viral oncoproteins that induce and propagate cellular transformation. An immune response generated during cisplatin/radiation therapy improves tumor clearance of HPV(+) cancers. Augmenting this induced response during therapy with an adenoviral HPV16 E6/E7 vaccine improves long term survival in preclinical models. Here we describe the generation of an HPV16 E6/E7 construct, which contains mutations that render E6/E7 non-oncogenic, while preserving antigenicity. These mutations do not allow E6/E7 to degrade p53, pRb, PTPN13, or activate telomerase. Non-oncogenic E6/E7 (E6Δ/E7Δ) expressed as a stable integrant, or in the [E1-, E2b-] adenovirus, lacks the ability to transform human cells while retaining the ability to induce an HPV specific immune response. Moreover, E6Δ/E7Δ plus chemotherapy/radiation statistically enhances clearance of established HPV(+) cancer in vivo. PMID:22918471

Longitudinal Associations among Renal Urea Clearance-Corrected Normalized Protein Catabolic Rate, Serum Albumin, and Mortality in Patients on Hemodialysis.

PubMed

Eriguchi, Rieko; Obi, Yoshitsugu; Streja, Elani; Tortorici, Amanda R; Rhee, Connie M; Soohoo, Melissa; Kim, Taehee; Kovesdy, Csaba P; Kalantar-Zadeh, Kamyar

2017-07-07

There are inconsistent reports on the association of dietary protein intake with serum albumin and outcomes among patients on hemodialysis. Using a new normalized protein catabolic rate (nPCR) variable accounting for residual renal urea clearance, we hypothesized that higher baseline nPCR and rise in nPCR would be associated with higher serum albumin and better survival among incident hemodialysis patients. Among 36,757 incident hemodialysis patients in a large United States dialysis organization, we examined baseline and change in renal urea clearance-corrected nPCR as a protein intake surrogate and modeled their associations with serum albumin and mortality over 5 years (1/2007-12/2011). Median nPCRs with and without accounting for renal urea clearance at baseline were 0.94 and 0.78 g/kg per day, respectively (median within-patient difference, 0.14 [interquartile range, 0.07-0.23] g/kg per day). During a median follow-up period of 1.4 years, 8481 deaths were observed. Baseline renal urea clearance-corrected nPCR was associated with higher serum albumin and lower mortality in the fully adjusted model ( P trend <0.001). Among 13,895 patients with available data, greater rise in renal urea clearance-corrected nPCR during the first 6 months was also associated with attaining high serum albumin (≥3.8 g/dl) and lower mortality ( P trend <0.001); compared with the reference group (a change of 0.1-0.2 g/kg per day), odds and hazard ratios were 0.53 (95% confidence interval, 0.44 to 0.63) and 1.32 (95% confidence interval, 1.14 to 1.54), respectively, among patients with a change of <-0.2 g/kg per day and 1.62 (95% confidence interval, 1.35 to 1.96) and 0.76 (95% confidence interval, 0.64 to 0.90), respectively, among those with a change of ≥0.5 g/kg per day. Within a given category of nPCR without accounting for renal urea clearance, higher levels of renal urea clearance-corrected nPCR consistently showed lower mortality risk. Among incident hemodialysis patients, higher dietary protein intake represented by nPCR and its changes over time appear to be associated with increased serum albumin levels and greater survival. nPCR may be underestimated when not accounting for renal urea clearance. Compared with the conventional nPCR, renal urea clearance-corrected nPCR may be a better marker of mortality. Copyright © 2017 by the American Society of Nephrology.

Pharmacokinetic modulation of oral etoposide by ketoconazole in patients with advanced cancer.

PubMed

Yong, Wei Peng; Desai, Apurva A; Innocenti, Federico; Ramirez, Jacqueline; Shepard, Dale; Kobayashi, Ken; House, Larry; Fleming, Gini F; Vogelzang, Nicholas J; Schilsky, Richard L; Ratain, Mark J

2007-11-01

Etoposide is a widely used cytotoxic drug that is commercially available in both intravenous and oral formulations. High interpatient pharmacokinetic variability has been associated with oral etoposide administration. Various strategies used in the past to reduce such variability have not been successful. Hence, this study was designed to evaluate if pharmacokinetic modulation of oral etoposide with ketoconazole could lead to a favorable alteration of etoposide pharmacokinetics, and to assess the feasibility and safety of this approach. Thirty-two patients were treated with ketoconazole 200 mg daily with an escalating dose of oral etoposide starting at a dose of 50 mg every other day. Pharmacokinetic samples were obtained during the first treatment cycle after the administration of an oral etoposide and ketoconazole dose. Additional baseline pharmacokinetic studies of etoposide alone were performed 4 days prior to the first treatment cycle. Dose limiting toxicities were neutropenia and fatigue. Ketoconazole increased the area under the plasma concentration-time curve (AUC) of oral etoposide by a median of 20% (p < 0.005). Ketoconazole did not reduce the interpatient variability in etoposide pharmacokinetics. Pretreatment bilirubin levels correlated with etoposide clearance (Spearman's r = -0.48, p = 0.008). The maximum tolerated dose was etoposide administered at 50 mg daily and ketoconazole 200 mg qd for 3 of 5 weeks. Ketoconazole reduces the apparent clearance of oral etoposide, does not alter its toxicity profile and does not reduce interpatient pharmacokinetic variability. Other methods to reduce the pharmacokinetic variability of oral etoposide are needed.

Immunogenetics of Seasonal Influenza Vaccine Response*

PubMed Central

Poland, Gregory A.; Ovsyannikova, Inna G.; Jacobson, Robert M.

2008-01-01

Seasonal influenza causes significant morbidity, mortality, and economic costs. Vaccines against influenza, though both safe and effective, are imperfect. Notably, these vaccines result in significant immune response variability across the population. The mechanism for this variability, in part, appears to lie in the polymorphisms of key immune response genes. Despite the importance of this variability, little in the way of genetic polymorphisms and its association with vaccine immune response to viral vaccines has been performed. Herein, we review and synthesize what is known about the immune response pathway and influenza viral immunity and then present original data from our laboratory on the immunogenetic relationships between HLA, cytokine and cytokine receptor gene polymorphisms and the variations in humoral immune response to inactivated seasonal influenza vaccine. Finally, we propose that a better understanding of vaccine immunogenetics offers insight towards the development of better influenza vaccines. PMID:19230157

Population pharmacokinetic study of teicoplanin in severely neutropenic patients.

PubMed Central

Lortholary, O; Tod, M; Rizzo, N; Padoin, C; Biard, O; Casassus, P; Guillevin, L; Petitjean, O

1996-01-01

The teicoplanin pharmacokinetics (PK) of 30 febrile and severely neutropenic patients (polymorphonuclear count, < 500/mm3) with hematologic malignancies were compared with those determined for five healthy volunteers (HV). Neutropenic patients were given piperacillin combined with amikacin, and teicoplanin was added to the regimen the day fever developed in patients suspected of having a staphylococcal infection or 48 h later. Teicoplanin was given intravenously at a dosage of 6 mg/kg of body weight at 0, 12, and 24 h and once a day thereafter. Five to eleven blood samples per patient were collected. Teicoplanin concentrations were measured by liquid chromatography. A bicompartmental model was fitted to the data by a nonlinear mixed-effect-model approach. Multiple-linear regression analysis was applied in an attempt to correlate PK parameters to nine covariates. The mean trough concentrations of teicoplanin 48 h after the onset of treatment and 24 h after the last injection (last trough) +/- standard deviations were 8.8 +/- 4.1 and 17.5 +/- 13.5 mg/liter, respectively. A significant increase was noted in the mean rate of elimination clearance of teicoplanin in neutropenic patients compared with that of HV (0.86 versus 0.73 liter/h, P = 0.002), as was the case with rates of distribution clearance (5.89 versus 4.94 liter/h, P = 0.002); the mean half-life of distribution was significantly shorter in patients than in HV (0.43 versus 0.61 h, P = 0.002). In contrast, the volumes of the central compartment (ca. 5.8 liters for both groups), the volumes of distribution at steady state (HV, 37.6 liters; patients, 55.9 liters), and the elimination half-lives (HV, 39.6 h; patients, 52.7 h) were not significantly different between HV and neutropenic patients. Interindividual variabilities of rates of clearance (coefficient of variation [CV], 43%) and elimination half-lives (CV, 56%) were mainly explained by the variabilities among rates of creatinine clearance. Interindividual variabilities of the volumes of the central compartment (CV, 33%) and the volumes of distribution at steady state (CV = 51%) were correlated to interindividual variabilities among numbers of leukocytes and the ages of patients, respectively. On the basis of the population PK model of teicoplanin, simulations were made to optimize the dosing schedule. A supplemental 6 mg/kg dose of teicoplanin at 36 h resulted in a trough concentration at 48 h of 16.0 +/- 4.5 mg/liter, with only 7% of patients having a trough concentration of less than 10 mg/liter, compared with 46% of patients on the usual schedule. PMID:8723474

Duct Diameter and Size of Stones Predict Successful Extracorporeal Shock Wave Lithotripsy and Endoscopic Clearance in Patients With Chronic Pancreatitis and Pancreaticolithiasis.

PubMed

Lapp, Robert T; Wolf, J Stuart; Faerber, Gary J; Roberts, William W; McCarthy, Sean T; Anderson, Michelle A; Wamsteker, Erik-Jan; Elta, Grace H; Scheiman, James M; Kwon, Richard S

2016-09-01

The need for endoscopic therapy before extracorporeal shock wave lithotripsy (SWL) to facilitate pancreatic duct stone removal is unclear. Predictive factors associated with successful fragmentation and subsequent complete duct clearance are variable. We hypothesize pancreatic duct strictures and large stones, but not pre-SWL endotherapy, correlate with successful fragmentation and complete duct clearance. A retrospective cohort study of patients with pancreaticolithiasis who underwent SWL and endoscopic retrograde cholangiopancreatography between January 2009 and June 2014 was evaluated. Thirty-seven patients were treated. Technical success (TS) of fragmentation was achieved in 22 patients (60%). Technical success was associated with fewer stones and SWL sessions and smaller stone and duct size. By multivariate logistic regression, only duct dilation was associated with TS. Endoscopic success of complete duct clearance was achieved in 29 patients (80%). Endoscopic success was more frequent with stones 12 mm or less and with successful TS. By multivariate logistic regression, stones greater than 12 mm were associated with endoscopic failure. Pre-SWL endotherapy does not affect stone fragmentation. Patients with a dilated duct (>8 mm) and pancreatic stones 12 mm or greater were associated with unsuccessful TS and endoscopic success, respectively, and may benefit from early referral for surgical decompression.

Population pharmacokinetics of oxycodone in patients with cancer-related pain.

PubMed

Komatsu, Toshiaki; Kokubun, Hideya; Suzuki, Ai; Takayanagi, Risa; Yamada, Yasuhiko; Matoba, Motohiro; Yago, Kazuo

2012-09-01

Oxycodone is an opioid widely prescribed to cancer patients for pain relief. However, the pharmacokinetics of oxycodone has not been sufficiently examined. Therefore the aim of this work was to study population pharmacokinetics of oxycodone in patients with cancer pain. The authors analyzed 108 serum oxycodone samples of 33 individuals with nonlinear mixed-effects model (NONMEM). Population pharmacokinetics was calculated using the one-compartment model of clearance, volume of distribution, bioavailability, absorption constant rate, and lag time. An exponential error model was used to determine interindividual variability and a relative error model was applied to assess residual variability. Population pharmacokinetics of oxycodone at the end point were as follows: CL(L/h) = 10.7 × [1 + (2 - Child-Pugh Classification)] (Class: A = 0, B = 1, C = 2); V(d) (L) = 193; k(a) (h(-1)) = 0.336; T(lag) (h) = 0.859; F (%) = 63.9. Interindividual variability was CL: 30.5%, V(d): 44.6%, and F: 37.0%, and residual variability was 16.2%. As the total clearance in patients with liver dysfunction (Child-Pugh class B) was reduced to 33.3%, serum concentration of oxycodone increased by 1.5. Therefore, it became clear that dose adjustments are essential when treating patients with liver dysfunction. These findings suggest that population parameters are useful for evaluating pharmacokinetics of oxycodone in patients with cancer pain.

Drug-Based Lead Discovery: The Novel Ablative Antiretroviral Profile of Deferiprone in HIV-1-Infected Cells and in HIV-Infected Treatment-Naive Subjects of a Double-Blind, Placebo-Controlled, Randomized Exploratory Trial

PubMed Central

Saxena, Deepti; Spino, Michael; Tricta, Fernando; Connelly, John; Cracchiolo, Bernadette M.; Hanauske, Axel-Rainer; D’Alliessi Gandolfi, Darlene; Mathews, Michael B.; Karn, Jonathan; Holland, Bart; Park, Myung Hee; Pe’ery, Tsafi; Palumbo, Paul E.; Hanauske-Abel, Hartmut M.

2016-01-01

Antiretrovirals suppress HIV-1 production yet spare the sites of HIV-1 production, the HIV-1 DNA-harboring cells that evade immune detection and enable viral resistance on-drug and viral rebound off-drug. Therapeutic ablation of pathogenic cells markedly improves the outcome of many diseases. We extend this strategy to HIV-1 infection. Using drug-based lead discovery, we report the concentration threshold-dependent antiretroviral action of the medicinal chelator deferiprone and validate preclinical findings by a proof-of-concept double-blind trial. In isolate-infected primary cultures, supra-threshold concentrations during deferiprone monotherapy caused decline of HIV-1 RNA and HIV-1 DNA; did not allow viral breakthrough for up to 35 days on-drug, indicating resiliency against viral resistance; and prevented, for at least 87 days off-drug, viral rebound. Displaying a steep dose-effect curve, deferiprone produced infection-independent deficiency of hydroxylated hypusyl-eIF5A. However, unhydroxylated deoxyhypusyl-eIF5A accumulated particularly in HIV-infected cells; they preferentially underwent apoptotic DNA fragmentation. Since the threshold, ascertained at about 150 μM, is achievable in deferiprone-treated patients, we proceeded from cell culture directly to an exploratory trial. HIV-1 RNA was measured after 7 days on-drug and after 28 and 56 days off-drug. Subjects who attained supra-threshold concentrations in serum and completed the protocol of 17 oral doses, experienced a zidovudine-like decline of HIV-1 RNA on-drug that was maintained off-drug without statistically significant rebound for 8 weeks, over 670 times the drug’s half-life and thus clearance from circulation. The uniform deferiprone threshold is in agreement with mapping of, and crystallographic 3D-data on, the active site of deoxyhypusyl hydroxylase (DOHH), the eIF5A-hydroxylating enzyme. We propose that deficiency of hypusine-containing eIF5A impedes the translation of mRNAs encoding proline cluster (‘polyproline’)-containing proteins, exemplified by Gag/p24, and facilitated by the excess of deoxyhypusine-containing eIF5A, releases the innate apoptotic defense of HIV-infected cells from viral blockade, thus depleting the cellular reservoir of HIV-1 DNA that drives breakthrough and rebound. Trial Registration: ClinicalTrial.gov NCT02191657 PMID:27191165

Safety, pharmacokinetics, metabolism and radiation dosimetry of 18F-tetrafluoroborate (18F-TFB) in healthy human subjects.

PubMed

Jiang, Huailei; Schmit, Nicholas R; Koenen, Alex R; Bansal, Aditya; Pandey, Mukesh K; Glynn, Robert B; Kemp, Bradley J; Delaney, Kera L; Dispenzieri, Angela; Bakkum-Gamez, Jamie N; Peng, Kah-Whye; Russell, Stephen J; Gunderson, Tina M; Lowe, Val J; DeGrado, Timothy R

2017-10-27

18 F-Tetrafluoroborate ( 18 F-TFB) is a promising iodide analog for PET imaging of thyroid cancer and sodium/iodide symporter (NIS) reporter activity in viral therapy applications. The aim of this study was to evaluate the safety, pharmacokinetics, biodistribution, and radiation dosimetry of high-specific activity 18 F-TFB in healthy human subjects. 18 F-TFB was synthesized with specific activity of 3.2 ± 1.3 GBq/μmol (at the end of synthesis). Dynamic and whole-body static PET/CT scans over 4 h were performed after intravenous administration of 18 F-TFB (333-407 MBq) in four female and four male healthy volunteers (35 ± 11 years old). Samples of venous blood and urine were collected over the imaging period and analyzed by ion-chromatography HPLC to determine tracer stability. Vital signs and clinical laboratory safety assays were measured to evaluate safety. 18 F-TFB administration was well tolerated with no significant findings on vital signs and no clinically meaningful changes in clinical laboratory assays. Left-ventricular blood pool time-activity curves showed a multi-phasic blood clearance of 18 F-radioactivity with the two rapid clearance phases over the first 20 min, followed by a slower clearance phase. HPLC analysis showed insignificant 18 F-labeled metabolites in the blood and urine over the length of the study (4 h). High uptakes were seen in the thyroid, stomach, salivary glands, and bladder. Urinary clearance of 18 F-TFB was prominent. Metabolic stability was evidenced by low accumulation of 18 F-radioactivity in the bone. Effective doses were 0.036 mSv/MBq in males and 0.064 mSv/MBq in females (p = 0.08, not significant). This initial study in healthy human subjects showed 18 F-TFB was safe and distributed in the human body similar to other iodide analogs. These data support further translational studies with 18 F-TFB as NIS gene reporter and imaging biomarker for thyroid cancer and other disease processes that import iodide.

Meeting Report: 2013 PDA Virus & TSE Safety Forum.

PubMed

Willkommen, Hannelore; Blümel, Johannes; Brorson, Kurt; Chen, Dayue; Chen, Qi; Gröner, Albrecht; Hubbard, Brian R; Kreil, Thomas R; Ruffing, Michel; Ruiz, Sol; Scott, Dorothy; Silvester, Glenda

2014-01-01

The report provides a summary of the presentations and discussions at the Virus & TSE Safety Forum 2013 organized by the Parenteral Drug Association (PDA) and held in Berlin, Germany, from June 4 to 6, 2013. The conference was accompanied by a workshop, "Virus Spike Preparations and Virus Removal by Filtration: New Trends and Developments". The presentations and the discussion at the workshop are summarized in a separate report that will be published in this issue of the journal as well. As with previous conferences of this series, the PDA Virus & TSE Safety Forum 2013 provided again an excellent opportunity to exchange information and opinions between the industry, research organizations, and regulatory bodies. Updates on regulatory considerations related to virus and transmissible spongiform encephalopathy (TSE) safety of biopharmaceuticals were provided by agencies of the European Union (EU), the United States (US), and Singapore. The epidemiology and detection methods of new emerging pathogens like hepatitis E virus and parvovirus (PARV 4) were exemplified, and the risk of contamination of animal-derived raw materials like trypsin was considered in particular. The benefit of using new sequence-based virus detection methods was discussed. Events of bioreactor contaminations in the past drew the attention to root cause investigations and preventive actions, which were illustrated by several examples. Virus clearance data of specific unit operations were provided; the discussion focused on the mechanism of virus clearance and on the strategic concept of viral clearance integration. As in previous years, the virus safety section was followed by a TSE section that covered recent scientific findings that may influence the risk assessment of blood and cell substrates. These included the realization that interspecies transmission of TSE by blood components in sheep is greater than predicted by assays in transgenic mice. Also, the pathogenesis and possibility of productive TSE infection of cell substrates were considered, and cell-based assays that may be suitable for use in TSE clearance studies were discussed. The current report provides an overview about the outcomes of the 2013 PDA Virus & TSE Safety Forum, a unique event in this field. © PDA, Inc. 2014.

Viral and bacterial contamination in a sedimentary aquifer in Uruguay: evaluation of coliforms as regional indicators of viral contamination.

NASA Astrophysics Data System (ADS)

Gamazo, Pablo; Colina, Rodney; Victoria, Matias; Alvareda, Elena; Burutatran, Luciana; Ramos, Julian; Olivera, María; Soler, Joan

2015-04-01

In many areas of Uruguay groundwater is the only source of water for human consumption and for industrial-agricultural economic activities. Traditionally considered as a safe source, groundwater is commonly used without any treatment. The Uruguayan law requires bacteriological (fecal) analysis for most water uses, but virological analyses are not mentioned in the legislation. In the Salto district, where groundwater is used for human consumption and for agricultural activities, bacterial contamination has been detected in several wells but no viruses analysis have been performed. The Republic University (UDELAR), with the support of the National Agency for Research and Innovation (ANII), is studying the incidence of virus and fecal bacteria in groundwater on an intensive agriculture area of the Salto district. An initial screening campaign of 44 wells was performed in which, besides total and fecal coliforms, rotavirus and adenovirus were detected. A subgroup of the screening wells (15) where selected for bimonthly sampling during a year. In accordance with literature results, single well data analysis shows that coliform and viral contamination can be considered as independent variables. However, when spatial data is integrated, coliform and viral contamination show linear correlation. In this work we present the survey results, we analyse the temporal incidence of variables like precipitation, temperature and chemical composition in well contamination and we discuss the value of coliforms as global indicator of viral contamination for the Salto aquifer.

Hepatitis C Virus: Viral Quasispecies and Genotypes.

PubMed

Tsukiyama-Kohara, Kyoko; Kohara, Michinori

2017-12-22

Hepatitis C virus (HCV) mainly replicates in the cytoplasm, where it easily establishes persistent infection, resulting in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Due to its high rate of mutation, HCV forms viral quasispecies, categorized based on the highly variable regions in the envelope protein and nonstructural 5A protein. HCV possesses seven major genotypes, among which genotype 1 is the most prevalent globally. The distribution of HCV genotypes varies based on geography, and each genotype has a different sensitivity to interferon treatment. Recently-developed direct-acting antivirals (DAAs), which target viral proteases or polymerases, mediate drastically better antiviral effects than previous therapeutics. Although treatment with DAAs has led to the development of drug-resistant HCV mutants, the most recently approved DAAs show improved pan-genomic activity, with a higher barrier to viral resistance.

Diversity of DNA and RNA Viruses in Indoor Air As Assessed via Metagenomic Sequencing.

PubMed

Rosario, Karyna; Fierer, Noah; Miller, Shelly; Luongo, Julia; Breitbart, Mya

2018-02-06

Diverse bacterial and fungal communities inhabit human-occupied buildings and circulate in indoor air; however, viral diversity in these man-made environments remains largely unknown. Here we investigated DNA and RNA viruses circulating in the air of 12 university dormitory rooms by analyzing dust accumulated over a one-year period on heating, ventilation, and air conditioning (HVAC) filters. A metagenomic sequencing approach was used to determine the identity and diversity of viral particles extracted from the HVAC filters. We detected a broad diversity of viruses associated with a range of hosts, including animals, arthropods, bacteria, fungi, humans, plants, and protists, suggesting that disparate organisms can contribute to indoor airborne viral communities. Viral community composition and the distribution of human-infecting papillomaviruses and polyomaviruses were distinct in the different dormitory rooms, indicating that airborne viral communities are variable in human-occupied spaces and appear to reflect differential rates of viral shedding from room occupants. This work significantly expands the known airborne viral diversity found indoors, enabling the design of sensitive and quantitative assays to further investigate specific viruses of interest and providing new insight into the likely sources of viruses found in indoor air.

Phage and Nucleocytoplasmic Large Viral Sequences Dominate Coral Viromes from the Arabian Gulf.

PubMed

Mahmoud, Huda; Jose, Liny

2017-01-01

Corals that naturally thrive under extreme conditions are gaining increasing attention due to their importance as living models to understand the impact of global warming on world corals. Here, we present the first metagenomic study of viral communities in corals thriving in a thermally variable water body in which the temperature fluctuates between 11 and 39°C in different seasons. The viral assemblages of two of the most abundant massive ( Porites harrisoni ) and branching ( Acropora downingi ) corals in offshore and inshore reef systems in the northern Arabian Gulf were investigated. Samples were collected from five reef systems during summer, autumn and winter of 2011/2012. The two coral viromes contain 12 viral families, including 10 dsDNA viral families [Siphoviridae, Podoviridae, Myoviridae, Phycodnaviridae, Baculoviridae, Herpesviridae, Adenoviridae, Alloherpesviridae, Mimiviridae and one unclassified family], one-ssDNA viral family (Microviridae) and one RNA viral family (Retroviridae). Overall, sequences significantly similar to Podoviridae were the most abundant in the P. harrisoni and A. downingi viromes. Various morphological types of virus-like particles (VLPs) were confirmed in the healthy coral tissue by transmission electron microscopy, including large tailless VLPs and electron-dense core VLPs. Tailed bacteriophages were isolated from coral tissue using a plaque assay. Higher functional gene diversity was recorded in A. downingi than in P. harrisoni , and comparative metagenomics revealed that the Gulf viral assemblages are functionally distinct from Pacific Ocean coral viral communities.

Serum adipokines and HIV viral replication in patients undergoing antiretroviral therapy

PubMed Central

Aramă, Victoria; Tilişcan, Cătălin; Ion, Daniela Adriana; Mihăilescu, Raluca; Munteanu, Daniela; Streinu-Cercel, Anca; Tudor, Ana Maria; Hristea, Adriana; Leoveanu, Viorica; Olaru, Ioana; Aramă, Ştefan Sorin

2012-01-01

Introduction Several studies have reported that cytokines secreted by adipose tissue (adipokines) may be linked to HIV replication. The aim of the study was to evaluate the relationship between HIV replication and serum levels of adipokines, in a Caucasian HIV-infected population of men and women undergoing complex antiretroviral therapy. Methods A cross-sectional study was conducted in an unselected sample of 77 HIV-1-positive patients. Serum adipokines levels were measured including circulating adiponectin, leptin, resistin, tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6). Patients were divided into two groups: Group 1 - with undetectable viral load and Group 2 - with persistent HIV viral replication. Differences between groups ? were tested using independent-sample t-test for Gaussian variables and Mann–Whitney–Wilcoxon test for non-parametric variables. Pearson's chi-squared test was used for correlation analysis. Results A total of 77 patients (age range: 17-65, mean: 32.5 years) including 44 men (57.1% men, age range: 17–63 years, mean: 34.1 years) and 33 women (42.9% women age range: 19–65 years, mean: 30.3 years) were included in the study. TNF-alpha had significantly higher serum levels in patients with detectable viral load (16.89 vs. 9.35 pg/mL), (p=0.043), but correlation analysis lacked statistical significance. Adiponectin had median serum levels of 9.22 ìg/mL in Group 1 vs. 16.50 ìg/mL in Group 2 but the results lacked statistical significance (p=0.059). Higher leptin, IL-6 and resistin serum levels were noted in patients with undetectable HIV viral load, without statistical significance. Conclusions The present study reported higher TNF-alpha serum levels in patients with persistent HIV viral load. We found no statistically significant correlations between adiponectin, leptin, resistin and IL-6 and HIV viral load in our Caucasian HIV-positive study population, undergoing antiretroviral therapy. PMID:24432258

Quality of Human Immunodeficiency Virus Viral Load Testing in Australia

PubMed Central

Best, Susan J.; Gust, Anthony P.; Johnson, Elizabeth I. M.; McGavin, Catherine H.; Dax, Elizabeth M.

2000-01-01

This study determined the proficiencies of laboratories measuring human immunodeficiency virus type 1 (HIV-1) viral loads and the accuracies of two assays used for HIV-1 viral load measurement in Australia and investigated the variability of the new versions of these assays. Quality assessment program panels containing (i) dilutions of HIV-1 subtype B, (ii) replicates of identical samples of HIV-1 subtype B, and (iii) samples of subtype E and B were tested by laboratories. Total variability (within and between laboratories) was tested with quality control samples. The coefficients of variation (CVs) for the Roche AMPLICOR HIV-1 MONITOR version (v) 1.0 and Chiron Quantiplex bDNA 2.0 assays ranged from 53 to 87% and 22 to 31%, respectively. The widespread occurrence of invalid runs with the AMPLICOR HIV-1 MONITOR 1.0 assay was identified. The CVs of the new versions of the assays were 82 to 86% for the AMPLICOR HIV-1 MONITOR v 1.5 assay and 16 to 23% for the Quantiplex bDNA 3.0 assay. For virus dilution samples, all but 5 of 19 laboratories obtained results within 2 standard deviations of the mean. The Quantiplex bDNA 2.0 assay reported values lower than those reported by the AMPLICOR HIV-1 MONITOR version 1.0 assay for samples containing HIV-1 subtype B, whereas the reverse was true for subtype E. Identification and resolution of the problem of invalid runs markedly improved the quality of HIV-1 viral load testing. The variability observed between laboratories and between assays, even the most recent versions, dictates that monitoring of viral load in an individual should always be by the same laboratory and by the same assay. Results for an individual which differ by less than 0.5 log10 HIV-1 RNA copy number/ml should not be considered clinically significant. PMID:11060062

Ex vivo detection of adenovirus specific CD4{sup +} T-cell responses to HLA-DR-epitopes of the Hexon protein show a contracted specificity of T{sub HELPER} cells following stem cell transplantation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serangeli, Celine; Bicanic, Oliver; Scheible, Michael H.

2010-02-20

Human adenovirus (HAdV) is a cause of significant morbidity and mortality in immunocompromised patients, especially after stem cell transplantation (SCT). Viral clearance has been attributed to CD4{sup +} T-cell responses against the Hexon-protein, but the frequency of specific T{sub HELPER} cells is extremely low or not detectable ex vivo and preference for different CD4{sup +} T-cell epitopes is variable among individuals. We therefore analyzed 44 healthy donors and 6 SCT-recipients for Hexon-specific CD4{sup +}-responses ex vivo, to identify epitopes which would be broadly applicable. We selected 19 candidate epitopes with predicted restriction to HLA-DR1/DR3/DR4/DR7; 16 were located within the highlymore » conserved regions, indicating cross-reactivity of T cells among HAdV-subspecies. Ten epitopes induced CD4{sup +}-proliferation in >50% of individuals, confirmed by intracellular IFN-gamma detection. Three SCT recipients who recovered from an infection with HAdV displayed reactivity towards only a single hexon epitope, whereas healthy individuals were responsive to two to eight epitopes (median 3). The ex vivo detection of Hexon-specific CD4{sup +} T-cells, without any long-term culture in vitro, enables the detection and generation of HAdV-specific CD4{sup +} T cells for adoptive T-cell transfer against HAdV-infection post SCT.« less

The mixed lineage kinase-3 inhibitor URMC-099 improves therapeutic outcomes for long-acting antiretroviral therapy.

PubMed

Zhang, Gang; Guo, Dongwei; Dash, Prasanta K; Araínga, Mariluz; Wiederin, Jayme L; Haverland, Nicole A; Knibbe-Hollinger, Jaclyn; Martinez-Skinner, Andrea; Ciborowski, Pawel; Goodfellow, Val S; Wysocki, Tadeusz A; Wysocki, Beata J; Poluektova, Larisa Y; Liu, Xin-Ming; McMillan, JoEllyn M; Gorantla, Santhi; Gelbard, Harris A; Gendelman, Howard E

2016-01-01

During studies to extend the half-life of crystalline nanoformulated antiretroviral therapy (nanoART) the mixed lineage kinase-3 inhibitor URMC-099, developed as an adjunctive neuroprotective agent was shown to facilitate antiviral responses. Long-acting ritonavir-boosted atazanavir (nanoATV/r) nanoformulations co-administered with URMC-099 reduced viral load and the numbers of HIV-1 infected CD4+ T-cells in lymphoid tissues more than either drug alone in infected humanized NOD/SCID/IL2Rγc-/- mice. The drug effects were associated with sustained ART depots. Proteomics analyses demonstrated that the antiretroviral responses were linked to affected phagolysosomal storage pathways leading to sequestration of nanoATV/r in Rab-associated recycling and late endosomes; sites associated with viral maturation. URMC-099 administered with nanoATV induced a dose-dependent reduction in HIV-1p24 and reverse transcriptase activity. This drug combination offers a unique chemical marriage for cell-based viral clearance. From the Clinical Editor: Although successful in combating HIV-1 infection, the next improvement in antiretroviral therapy (nanoART) would be to devise long acting therapy, such as intra-cellular depots. In this report, the authors described the use of nanoformulated antiretroviral therapy given together with the mixed lineage kinase-3 inhibitor URMC-099, and showed that this combination not only prolonged drug half-life, but also had better efficacy. The findings are hoped to be translated into the clinical setting in the future. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Histone deacetylase inhibitors containing a benzamide functional group and a pyridyl cap are preferentially effective human immunodeficiency virus-1 latency-reversing agents in primary resting CD4+ T cells

PubMed Central

Gélinas, Céline

2017-01-01

Antiretroviral therapy (ART) can control human immunodeficiency virus-1 (HIV-1) replication in infected individuals. Unfortunately, patients remain persistently infected owing to the establishment of latent infection requiring that ART be maintained indefinitely. One strategy being pursued involves the development of latency-reversing agents (LRAs) to eliminate the latent arm of the infection. One class of molecules that has been tested for LRA activity is the epigenetic modulating compounds histone deacetylases inhibitors (HDACis). Previously, initial screening of these molecules typically commenced using established cell models of viral latency, and although certain drugs such as the HDACi suberoylanilide hydroxamic acid demonstrated strong activity in these models, it did not translate to comparable activity with patient samples. Here we developed a primary cell model of viral latency using primary resting CD4+ T cells infected with Vpx-complemented HIV-1 and found that the activation profile using previously described LRAs mimicked that obtained with patient samples. This primary cell model was used to evaluate 94 epigenetic compounds. Not surprisingly, HDACis were found to be the strongest activators. However, within the HDACi class, the most active LRAs with the least pronounced toxicity contained a benzamide functional moiety with a pyridyl cap group, as exemplified by the HDACi chidamide. The results indicate that HDACis with a benzamide moiety and pyridyl cap group should be considered for further drug development in the pursuit of a successful viral clearance strategy. PMID:28113052

Parasite-mediated upregulation of NK cell-derived gamma interferon protects against severe highly pathogenic H5N1 influenza virus infection.

PubMed

O'Brien, Kevin B; Schultz-Cherry, Stacey; Knoll, Laura J

2011-09-01

Outbreaks of influenza A viruses are associated with significant human morbidity worldwide. Given the increasing resistance to the available influenza drugs, new therapies for the treatment of influenza virus infection are needed. An alternative approach is to identify products that enhance a protective immune response. In these studies, we demonstrate that infecting mice with the Th1-inducing parasite Toxoplasma gondii prior to highly pathogenic avian H5N1 influenza virus infection led to decreased lung viral titers and enhanced survival. A noninfectious fraction of T. gondii soluble antigens (STAg) elicited an immune response similar to that elicited by live parasites, and administration of STAg 2 days after H5N1 influenza virus infection enhanced survival, lowered viral titers, and reduced clinical disease. STAg administration protected H5N1 virus-infected mice lacking lymphocytes, suggesting that while the adaptive immune response was not required for enhanced survival, it was necessary for STAg-mediated viral clearance. Mechanistically, we found that administration of STAg led to increased production of gamma interferon (IFN-γ) from natural killer (NK) cells, which were both necessary and sufficient for survival. Further, administration of exogenous IFN-γ alone enhanced survival from H5N1 influenza virus infection, although not to the same level as STAg treatment. These studies demonstrate that a noninfectious T. gondii extract enhances the protective immune response against severe H5N1 influenza virus infections even when a single dose is administered 2 days postinfection.

Human and Mouse Eosinophils Have Antiviral Activity against Parainfluenza Virus

PubMed Central

Bivins-Smith, Elizabeth R.; Nie, Zhenying; Scott, Gregory D.; Lee, James J.; Lee, Nancy A.; Fryer, Allison D.; Jacoby, David B.

2016-01-01

Respiratory viruses cause asthma exacerbations. Because eosinophils are the prominent leukocytes in the airways of 60–70% of patients with asthma, we evaluated the effects of eosinophils on a common respiratory virus, parainfluenza 1, in the lung. Eosinophils recruited to the airways of wild-type mice after ovalbumin sensitization and challenge significantly decreased parainfluenza virus RNA in the lungs 4 days after infection compared with nonsensitized animals. This antiviral effect was also seen in IL-5 transgenic mice with an abundance of airway eosinophils (NJ.1726) but was lost in transgenic eosinophil-deficient mice (PHIL) and in IL-5 transgenic mice crossed with eosinophil-deficient mice (NJ.1726-PHIL). Loss of the eosinophil granule protein eosinophil peroxidase, using eosinophil peroxidase–deficient transgenic mice, did not reduce eosinophils’ antiviral effect. Eosinophil antiviral mechanisms were also explored in vitro. Isolated human eosinophils significantly reduced parainfluenza virus titers. This effect did not involve degradation of viral RNA by eosinophil granule RNases. However, eosinophils treated with a nitric oxide synthase inhibitor lost their antiviral activity, suggesting eosinophils attenuate viral infectivity through production of nitric oxide. Consequently, eosinophil nitric oxide production was measured with an intracellular fluorescent probe. Eosinophils produced nitric oxide in response to virus and to a synthetic agonist of the virus-sensing innate immune receptor, Toll-like receptor (TLR) 7. IFNγ increased expression of eosinophil TLR7 and potentiated TLR7-induced nitric oxide production. These results suggest that eosinophils promote viral clearance in the lung and contribute to innate immune responses against respiratory virus infections in humans. PMID:27049514

Human and Mouse Eosinophils Have Antiviral Activity against Parainfluenza Virus.

PubMed

Drake, Matthew G; Bivins-Smith, Elizabeth R; Proskocil, Becky J; Nie, Zhenying; Scott, Gregory D; Lee, James J; Lee, Nancy A; Fryer, Allison D; Jacoby, David B

2016-09-01

Respiratory viruses cause asthma exacerbations. Because eosinophils are the prominent leukocytes in the airways of 60-70% of patients with asthma, we evaluated the effects of eosinophils on a common respiratory virus, parainfluenza 1, in the lung. Eosinophils recruited to the airways of wild-type mice after ovalbumin sensitization and challenge significantly decreased parainfluenza virus RNA in the lungs 4 days after infection compared with nonsensitized animals. This antiviral effect was also seen in IL-5 transgenic mice with an abundance of airway eosinophils (NJ.1726) but was lost in transgenic eosinophil-deficient mice (PHIL) and in IL-5 transgenic mice crossed with eosinophil-deficient mice (NJ.1726-PHIL). Loss of the eosinophil granule protein eosinophil peroxidase, using eosinophil peroxidase-deficient transgenic mice, did not reduce eosinophils' antiviral effect. Eosinophil antiviral mechanisms were also explored in vitro. Isolated human eosinophils significantly reduced parainfluenza virus titers. This effect did not involve degradation of viral RNA by eosinophil granule RNases. However, eosinophils treated with a nitric oxide synthase inhibitor lost their antiviral activity, suggesting eosinophils attenuate viral infectivity through production of nitric oxide. Consequently, eosinophil nitric oxide production was measured with an intracellular fluorescent probe. Eosinophils produced nitric oxide in response to virus and to a synthetic agonist of the virus-sensing innate immune receptor, Toll-like receptor (TLR) 7. IFNγ increased expression of eosinophil TLR7 and potentiated TLR7-induced nitric oxide production. These results suggest that eosinophils promote viral clearance in the lung and contribute to innate immune responses against respiratory virus infections in humans.

The mechanisms of delayed onset type adverse reactions to oseltamivir

PubMed Central

Hama, Rokuro

2016-01-01

Abstract Oseltamivir is recommended for the treatment and prophylaxis of influenza in persons at higher risk for influenza complications such as individuals with diabetes, neuropsychiatric illnesses, and respiratory, cardiac, renal, hepatic or haematological diseases. However, a recent Cochrane review reported that reduction of antibody production, renal disorders, hyperglycaemia, psychiatric disorders, and QT prolongation may be related to oseltamivir use. The underlying mechanisms are reviewed. There is decisive evidence that administration of a clinically compatible dose of oseltamivir in mice challenged by a respiratory syncytial virus (RSV) that lacks a neuraminidase gene showed symptom-relieving effects and inhibition of viral clearance. These effects were accompanied by decreased level of T cell surface sialoglycosphingolipid (ganglioside) GM1 that is regulated by the endogenous neuraminidase in response to viral challenge. Clinical and non-clinical evidence supports the view that the usual dose of oseltamivir suppresses pro-inflammatory cytokines such as interferon-gamma, interleukin-6, and tumour necrosis factor-alpha almost completely with partial suppression of viral shedding in human influenza virus infection experiment. Animal toxicity tests support the clinical evidence with regard to renal and cardiac disorders (bradycardia and QT prolongation) and do not disprove the metabolic effect. Reduction of antibody production and cytokine induction and renal, metabolic, cardiac, and prolonged psychiatric disorders after oseltamivir use may be related to inhibition of the host’s endogenous neuraminidase. While the usual clinical dose of zanamivir may not have this effect, a higher dose or prolonged administration of zanamivir and other neuraminidase inhibitors may induce similar delayed reactions, including reduction of the antibody and/or cytokine production. PMID:27251370

Memory CD8+ T cells are sufficient to alleviate impaired host resistance to influenza A virus infection caused by neonatal oxygen supplementation.

PubMed

Giannandrea, Matthew; Yee, Min; O'Reilly, Michael A; Lawrence, B Paige

2012-09-01

Supplemental oxygen administered to preterm infants is an important clinical intervention, but it is associated with life-long changes in lung development and increased sensitivity to respiratory viral infections. The precise immunological changes caused by neonatal oxygen treatment remain poorly understood. We previously reported that adult mice exposed to supplemental oxygen as neonates display persistent pulmonary inflammation and enhanced mortality after a sublethal influenza A virus infection. These changes suggest that neonatal hyperoxia impairs the cytotoxic CD8(+) T cell response required to clear the virus. In this study, we show that although host resistance to several different strains of influenza A virus is reduced by neonatal hyperoxia, this treatment does not impair viral clearance, nor does it alter the magnitude of the virus-specific CD8(+) T cell response to primary infection. Moreover, memory T cells are sufficient to ameliorate the increased morbidity and mortality and alleviate the excessive lung damage observed in mice exposed to high oxygen levels as neonates, and we attribute this sufficiency principally to virus-specific memory CD8(+) T cells. Thus, we show that neonatal hyperoxia reduces host resistance to influenza virus infection without diminishing the function of cytotoxic T lymphocytes or the generation of virus-specific memory T cells and that CD8(+) memory T cells are sufficient to provide protection from negative consequences of this important life-saving intervention. Our findings suggest that vaccines that generate robust T cell memory may be efficacious at reducing the increased sensitivity to respiratory viral infections in people born prematurely.

Virology, serology, and demography of hepatitis E viremic blood donors in South East England.

PubMed

Tedder, Richard S; Tettmar, Kate I; Brailsford, Su R; Said, Bengu; Ushiro-Lumb, Ines; Kitchen, Alan; Morgan, Dilys; Lattimore, Sam; Tossell, Joanne; Ijaz, Samreen; Hewitt, Patricia E

2016-06-01

Hepatitis E virus (HEV) Genotype 3 (G3) in England comprises two principal phylogenetic groups (Group 1 and Group 2) and can be transmitted by transfusion. Unselected screening identified 79 viremic donors; 76 participated in a follow-up study. Viral RNA dynamics, phylogenetics, and seroconversion were characterized in the donors. Detailed demographic, travel, clinical, and lifestyle questionnaires were undertaken. The majority of viremic individuals (57/79) were seronegative at time of donation but all seroconverted. Viremia was short-lived, with a median of 6.5 weeks to confirmed viral clearance. All infections were acquired in the United Kingdom and were G3, with Group 2 viruses predominating (43/54; 80%). Infection was associated with some clinical symptoms both at and after donation (8/77; 10%). Viral loads and symptoms were more pronounced in Group 1 infections. There was no serologic evidence of reinfection. Donors were more commonly male (p = 0.002); both male and female donors were older than comparator donors. Animal contact was unlikely to be the source of infection. Consumption of chicken and pig meat was common to all infected donors; processed pig meat was most commonly purchased from one particular retail chain. Viremic donors represent primary infection in older members of the community and reflect a widespread zoonotic in the United Kingdom. The two phylogenetic groups of HEV G3 display different pathogenicity and the more common Group 2 appears less adapted to humans. There are no objective demographic criteria that can identify donors at enhanced HEV risk. © 2016 AABB.

Nipah virion entry kinetics, composition, and conformational changes determined by enzymatic virus-like particles and new flow virometry tools.

PubMed

Landowski, Matthew; Dabundo, Jeffrey; Liu, Qian; Nicola, Anthony V; Aguilar, Hector C

2014-12-01

Virus-cell membrane fusion is essential for enveloped virus infections. However, mechanistic viral membrane fusion studies have predominantly focused on cell-cell fusion models, largely due to the low availability of technologies capable of characterizing actual virus-cell membrane fusion. Although cell-cell fusion assays are valuable, they do not fully recapitulate all the variables of virus-cell membrane fusion. Drastic differences between viral and cellular membrane lipid and protein compositions and curvatures exist. For biosafety level 4 (BSL4) pathogens such as the deadly Nipah virus (NiV), virus-cell fusion mechanistic studies are notably cumbersome. To circumvent these limitations, we used enzymatic Nipah virus-like-particles (NiVLPs) and developed new flow virometric tools. NiV's attachment (G) and fusion (F) envelope glycoproteins mediate viral binding to the ephrinB2/ephrinB3 cell receptors and virus-cell membrane fusion, respectively. The NiV matrix protein (M) can autonomously induce NiV assembly and budding. Using a β-lactamase (βLa) reporter/NiV-M chimeric protein, we produced NiVLPs expressing NiV-G and wild-type or mutant NiV-F on their surfaces. By preloading target cells with the βLa fluorescent substrate CCF2-AM, we obtained viral entry kinetic curves that correlated with the NiV-F fusogenic phenotypes, validating NiVLPs as suitable viral entry kinetic tools and suggesting overall relatively slower viral entry than cell-cell fusion kinetics. Additionally, the proportions of F and G on individual NiVLPs and the extent of receptor-induced conformational changes in NiV-G were measured via flow virometry, allowing the proper interpretation of the viral entry kinetic phenotypes. The significance of these findings in the viral entry field extends beyond NiV to other paramyxoviruses and enveloped viruses. Virus-cell membrane fusion is essential for enveloped virus infections. However, mechanistic viral membrane fusion studies have predominantly focused on cell-cell fusion models, largely due to the low availability of technologies capable of characterizing actual virus-cell membrane fusion. Although cell-cell fusion assays are valuable, they do not fully recapitulate all the variables of virus-cell membrane fusion. For example, drastic differences between viral and cellular membrane lipid and protein compositions and curvatures exist. For biosafety level 4 (BSL4) pathogens such as the deadly Nipah virus (NiV), virus-cell fusion mechanistic studies are especially cumbersome. To circumvent these limitations, we used enzymatic Nipah virus-like-particles (NiVLPs) and developed new flow virometric tools. Our new tools allowed us the high-throughput measurement of viral entry kinetics, glycoprotein proportions on individual viral particles, and receptor-induced conformational changes in viral glycoproteins on viral surfaces. The significance of these findings extends beyond NiV to other paramyxoviruses and enveloped viruses. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Population Pharmacokinetic Analyses of Lithium: A Systematic Review.

PubMed

Methaneethorn, Janthima

2018-02-01

Even though lithium has been used for the treatment of bipolar disorder for several decades, its toxicities are still being reported. The major limitation in the use of lithium is its narrow therapeutic window. Several methods have been proposed to predict lithium doses essential to attain therapeutic levels. One of the methods used to guide lithium therapy is population pharmacokinetic approach which accounts for inter- and intra-individual variability in predicting lithium doses. Several population pharmacokinetic studies of lithium have been conducted. The objective of this review is to provide information on population pharmacokinetics of lithium focusing on nonlinear mixed effect modeling approach and to summarize significant factors affecting lithium pharmacokinetics. A literature search was conducted from PubMed database from inception to December, 2016. Studies conducted in humans, using lithium as a study drug, providing population pharmacokinetic analyses of lithium by means of nonlinear mixed effect modeling, were included in this review. Twenty-four articles were identified from the database. Seventeen articles were excluded based on the inclusion and exclusion criteria. A total of seven articles were included in this review. Of these, only one study reported a combined population pharmacokinetic-pharmacodynamic model of lithium. Lithium pharmacokinetics were explained using both one- and two-compartment models. The significant predictors of lithium clearance identified in most studies were renal function and body size. One study reported a significant effect of age on lithium clearance. The typical values of lithium clearance ranged from 0.41 to 9.39 L/h. The magnitude of inter-individual variability on lithium clearance ranged from 12.7 to 25.1%. Only two studies evaluated the models using external data sets. Model methodologies in each study are summarized and discussed in this review. For future perspective, a population pharmacokinetic-pharmacodynamic study of lithium is recommended. Moreover, external validation of previously published models should be performed.

Effect of temperature on the pharmacokinetics of benzocaine in rainbow trout (Oncorhynchus mykiss) after bath exposures

USGS Publications Warehouse

Stehly, G.R.; Meinertz, J.R.; Gingerich, W.H.

1998-01-01

The pharmacokinetics of benzocaine during bath exposures at 1 mg/L were determined in rainbow trout acclimated at 6 °C, 12 °C or 18 °C for at least 1 month. Individual fish were exposed to benzocaine in a recirculating system for 4 h and pharmacokinetic parameters were estimated in a unique manner from the concentration of benzocaine in the bath water vs. time curve. Elimination from plasma was also determined after the 4 h exposure. The uptake clearance and metabolic clearance increased with increased acclimatization temperatures (uptake clearance 581 ± 179 mL/min/kg at 6 °C and 1154 ± 447 mL/ min/kg at 18 °C; metabolic clearance 15.2 ± 4.1 mL/min/kg at 6 °C and 22.3 ± 4.2 mL/min/kg at 18 °C). The apparent volume of distribution had a trend for increasing with temperature that was not significant at the 5% level (2369 ± 678 mL/kg at 6 °C to 3260 ± 1182 mL/kg at 18 °C). The elimination half-life of benzocaine in plasma was variable and did not differ significantly with temperature (60.8 ± 30.3 min at 6 °C to 35.9 ± 13.0 min at 12 °C). Elimination of benzocaine from rainbow trout is relatively rapid and even more rapid at higher acclimatization temperatures based on calculated metabolic clearances and measured plasma concentrations, but was not evident by measurement of terminal plasma half-lifes.

The effects of laterality on obstacle crossing performance in unilateral trans-tibial amputees.

PubMed

De Asha, Alan R; Buckley, John G

2015-05-01

Unilateral trans-tibial amputees have bilaterally reduced toe clearance, and an increased risk of foot contact, while crossing obstacles compared to the able-bodied. While the able-bodied tend to lead with a 'preferred' limb it is equivocal whether amputees prefer to lead with the intact or prosthetic limb. This study determined the effects of laterality, compared to side of amputation, on amputees' obstacle crossing performance. To help understand why laterality could affect performance we also assessed knee proprioception for both limbs. Foot placement and toe clearance parameters were recorded while nine amputees crossed obstacles of varying heights leading with both their intact and prosthetic limbs. Joint-position sense was also assessed. Participants self-reported which limb was their preferred (dominant) limb. There were no significant differences in foot placements or toe clearance variability across lead-limb conditions. There were no significant differences in toe clearance between intact and prosthetic lead-limbs (p=0.28) but toe clearance was significantly higher when amputees led with their preferred compared to non-preferred limb (p=0.025). There was no difference in joint-position sense between the intact and residual knees (p=0.34) but joint-position sense tended to be more accurate for the preferred, compared to non-preferred limb (p=0.08). Findings suggest that, despite the mechanical constraints imposed by use of a prosthesis, laterality may be as important in lower-limb amputees as it is in the able bodied. This suggests that amputees should be encouraged to cross obstacles leading with their preferred limb. Copyright © 2015. Published by Elsevier Ltd.

Glymphatic fluid transport controls paravascular clearance of AAV vectors from the brain

PubMed Central

Murlidharan, Giridhar; Crowther, Andrew; Reardon, Rebecca A.; Song, Juan

2016-01-01

Adeno-associated viruses (AAV) are currently being evaluated in clinical trials for gene therapy of CNS disorders. However, host factors that influence the spread, clearance, and transduction efficiency of AAV vectors in the brain are not well understood. Recent studies have demonstrated that fluid flow mediated by aquaporin-4 (AQP4) channels located on astroglial end feet is essential for exchange of solutes between interstitial and cerebrospinal fluid. This phenomenon, which is essential for interstitial clearance of solutes from the CNS, has been termed glial-associated lymphatic transport or glymphatic transport. In the current study, we demonstrate that glymphatic transport profoundly affects various aspects of AAV gene transfer in the CNS. Altered localization of AQP4 in aged mouse brains correlated with significantly increased retention of AAV vectors in the parenchyma and reduced systemic leakage following ventricular administration. We observed a similar increase in AAV retention and transgene expression upon i.c.v. administration in AQP4–/– mice. Consistent with this observation, fluorophore-labeled AAV vectors showed markedly reduced flux from the ventricles of AQP4–/– mice compared with WT mice. These results were further corroborated by reduced AAV clearance from the AQP4-null brain, as demonstrated by reduced transgene expression and vector genome accumulation in systemic organs. We postulate that deregulation of glymphatic transport in aged and diseased brains could markedly affect the parenchymal spread, clearance, and gene transfer efficiency of AAV vectors. Assessment of biomarkers that report the kinetics of CSF flux in prospective gene therapy patients might inform variable treatment outcomes and guide future clinical trial design. PMID:27699236

Clonorchis sinensis Co-infection Could Affect the Disease State and Treatment Response of HBV Patients.

PubMed

Li, Wenfang; Dong, Huimin; Huang, Yan; Chen, Tingjin; Kong, Xiangzhan; Sun, Hengchang; Yu, Xinbing; Xu, Jin

2016-06-01

Clonorchis sinensis (C. sinensis) is considered to be an important parasitic zoonosis because it infects approximately 35 million people, while approximately 15 million were distributed in China. Hepatitis B virus (HBV) infection is a major public health issue. Two types of pathogens have the potential to cause human liver disease and eventually hepatocellular carcinoma. Concurrent infection with HBV and C. sinensis is often observed in some areas where C. sinensis is endemic. However, whether C. sinensis could impact HBV infection or vice versa remains unknown. Co-infection with C. sinensis and HBV develops predominantly in males. Co-infected C. sinensis and HBV patients presented weaker liver function and higher HBV DNA titers. Combination treatment with antiviral and anti-C. sinensis drugs in co-infected patients could contribute to a reduction in viral load and help with liver function recovery. Excretory-secretory products (ESPs) may, in some ways, increase HBV viral replication in vitro. A mixture of ESP and HBV positive sera could induce peripheral blood mononuclear cells (PBMCs) to produce higher level of Th2 cytokines including IL-4, IL-6 and IL-10 compared to HBV alone, it seems that due to presence of ESP, the cytokine production shift towards Th2. C. sinensis/HBV co-infected patients showed higher serum IL-6 and IL-10 levels and lower serum IFN-γ levels. Patients with concomitant C. sinensis and HBV infection presented weaker liver function and higher HBV DNA copies. In co-infected patients, the efficacy of anti-viral treatment was better in patients who were prescribed with entecavir and praziquantel than entecavir alone. One possible reason for the weaker response to antiviral therapies in co-infected patients was the shift in cytokine production from Th1 to Th2 that may inhibit viral clearance. C. sinensis/HBV co-infection could exacerbate the imbalance of Th1/Th2 cytokine.

Clonorchis sinensis Co-infection Could Affect the Disease State and Treatment Response of HBV Patients

PubMed Central

Huang, Yan; Chen, Tingjin; Kong, Xiangzhan; Sun, Hengchang; Yu, Xinbing; Xu, Jin

2016-01-01

Background Clonorchis sinensis (C. sinensis) is considered to be an important parasitic zoonosis because it infects approximately 35 million people, while approximately 15 million were distributed in China. Hepatitis B virus (HBV) infection is a major public health issue. Two types of pathogens have the potential to cause human liver disease and eventually hepatocellular carcinoma. Concurrent infection with HBV and C. sinensis is often observed in some areas where C. sinensis is endemic. However, whether C. sinensis could impact HBV infection or vice versa remains unknown. Principal Findings Co-infection with C. sinensis and HBV develops predominantly in males. Co-infected C. sinensis and HBV patients presented weaker liver function and higher HBV DNA titers. Combination treatment with antiviral and anti-C. sinensis drugs in co-infected patients could contribute to a reduction in viral load and help with liver function recovery. Excretory-secretory products (ESPs) may, in some ways, increase HBV viral replication in vitro. A mixture of ESP and HBV positive sera could induce peripheral blood mononuclear cells (PBMCs) to produce higher level of Th2 cytokines including IL-4, IL-6 and IL-10 compared to HBV alone, it seems that due to presence of ESP, the cytokine production shift towards Th2. C. sinensis/HBV co-infected patients showed higher serum IL-6 and IL-10 levels and lower serum IFN-γ levels. Conclusions/Significance Patients with concomitant C. sinensis and HBV infection presented weaker liver function and higher HBV DNA copies. In co-infected patients, the efficacy of anti-viral treatment was better in patients who were prescribed with entecavir and praziquantel than entecavir alone. One possible reason for the weaker response to antiviral therapies in co-infected patients was the shift in cytokine production from Th1 to Th2 that may inhibit viral clearance. C. sinensis/HBV co-infection could exacerbate the imbalance of Th1/Th2 cytokine. PMID:27348302

Lessons learned from a double-blind randomised placebo-controlled study with a iota-carrageenan nasal spray as medical device in children with acute symptoms of common cold

PubMed Central

2012-01-01

Background Common cold is caused by a variety of respiratory viruses. The prevalence in children is high, and it potentially contributes to significant morbidity. Iota-carragenan, a polymer derived from red seaweed, has reduced viral load in nasal secretions and alleviated symptoms in adults with common cold. Methods We have assessed the antiviral and therapeutic activity of a nasal spray containing iota-carrageenan in children with acute symptoms of common cold. A cohort of 153 children between 1–18 years (mean age 5 years), displaying acute symptoms of common cold were randomly assigned to treatment with a nasal spray containing iota-carrageenan (0.12%) as verum or 0.9% sodium chloride solution as placebo for seven days. Symptoms of common cold were recorded and the viral load of respiratory viruses in nasal secretions was determined at two consecutive visits. Results The results of the present study showed no significant difference between the iota carrageenan and the placebo group on the mean of TSS between study days 2–7. Secondary endpoints, such as reduced time to clearance of disease (7.6 vs 9.4 days; p = 0.038), reduction of viral load (p = 0.026), and lower incidence of secondary infections with other respiratory viruses (p = 0.046) indicated beneficial effects of iota-carrageenan in this population. The treatment was safe and well tolerated, with less side effects observed in the verum group compared to placebo. Conclusion In this study iota-carrageenan did not alleviate symptoms in children with acute symptoms of common cold, but significantly reduced viral load in nasal secretions that may have important implications for future studies. Trial registration ISRCTN52519535, http://www.controlled-trials.com/ISRCTN52519535/ PMID:22950667

Immunogenetic studies of the hepatitis C virus infection in an era of pan-genotype antiviral therapies - Effective treatment is coming.

PubMed

Ellwanger, Joel Henrique; Kaminski, Valéria de Lima; Valverde-Villegas, Jacqueline María; Simon, Daniel; Lunge, Vagner Ricardo; Chies, José Artur Bogo

2017-08-12

What are the factors that influence human hepatitis C virus (HCV) infection, hepatitis status establishment, and disease progression? Firstly, one has to consider the genetic background of the host and HCV genotypes. The immunogenetic host profile will reflect how each infected individual deals with infection. Secondly, there are environmental factors that drive susceptibility or resistance to certain viral strains. These will dictate (I) the susceptibility to infection; (II) whether or not an infected person will promote viral clearance; (III) the immune response and the response profile to therapy; and (IV) whether and how long it would take to the development of HCV-associated diseases, as well as their severity. Looking at this scenario, this review addresses clinical aspects of HCV infection, following by an update of molecular and cellular features of the immune response against the virus. The evasion mechanisms used by HCV are presented, considering the potential role of exosomes in infection. Genetic factors influencing HCV infection and pathogenesis are the main topics of the article. Shortly, HLAs, MBLs, TLRs, ILs, and IFNLs genes have relevant roles in the susceptibility to HCV infection. In addition, ILs, IFNLs, as well as TLRs genes are important modulators of HCV-associated diseases. The viral aspects that influence HCV infection are presented, followed by a discussion about evolutionary aspects of host and HCV interaction. HCV and HIV infections are close related. Thus, we also present a discussion about HIV/HCV co-infection, focusing on cellular and molecular aspects of this interaction. Pharmacogenetics and treatment of HCV infection are the last topics of this review. The understanding of how the host genetics interacts with viral and environmental factors is crucial for the development of new strategies to prevent HCV infection, even in an era of potential development of pan-genotypic antivirals. Copyright © 2017 Elsevier B.V. All rights reserved.

Improvement of ALT decay kinetics by all-oral HCV treatment: Role of NS5A inhibitors and differences with IFN-based regimens

PubMed Central

Cento, Valeria; Nguyen, Thi Huyen Tram; Di Carlo, Domenico; Biliotti, Elisa; Gianserra, Laura; Lenci, Ilaria; Di Paolo, Daniele; Calvaruso, Vincenza; Teti, Elisabetta; Cerrone, Maddalena; Romagnoli, Dante; Melis, Michela; Danieli, Elena; Menzaghi, Barbara; Polilli, Ennio; Siciliano, Massimo; Nicolini, Laura Ambra; Di Biagio, Antonio; Magni, Carlo Federico; Bolis, Matteo; Antonucci, Francesco Paolo; Di Maio, Velia Chiara; Alfieri, Roberta; Sarmati, Loredana; Casalino, Paolo; Bernardini, Sergio; Micheli, Valeria; Rizzardini, Giuliano; Parruti, Giustino; Quirino, Tiziana; Puoti, Massimo; Babudieri, Sergio; D’Arminio Monforte, Antonella; Andreoni, Massimo; Craxì, Antonio; Angelico, Mario; Pasquazzi, Caterina; Taliani, Gloria; Guedj, Jeremie; Ceccherini-Silberstein, Francesca

2017-01-01

Background Intracellular HCV-RNA reduction is a proposed mechanism of action of direct-acting antivirals (DAAs), alternative to hepatocytes elimination by pegylated-interferon plus ribavirin (PR). We modeled ALT and HCV-RNA kinetics in cirrhotic patients treated with currently-used all-DAA combinations to evaluate their mode of action and cytotoxicity compared with telaprevir (TVR)+PR. Study design Mathematical modeling of ALT and HCV-RNA kinetics was performed in 111 HCV-1 cirrhotic patients, 81 treated with all-DAA regimens and 30 with TVR+PR. Kinetic-models and Cox-analysis were used to assess determinants of ALT-decay and normalization. Results HCV-RNA kinetics was biphasic, reflecting a mean effectiveness in blocking viral production >99.8%. The first-phase of viral-decline was faster in patients receiving NS5A-inhibitors compared to TVR+PR or sofosbuvir+simeprevir (p<0.001), reflecting higher efficacy in blocking assembly/secretion. The second-phase, noted δ and attributed to infected-cell loss, was faster in patients receiving TVR+PR or sofosbuvir+simeprevir compared to NS5A-inhibitors (0.27 vs 0.21 d-1, respectively, p = 0.0012). In contrast the rate of ALT-normalization, noted λ, was slower in patients receiving TVR+PR or sofosbuvir+simeprevir compared to NS5A-inhibitors (0.17 vs 0.27 d-1, respectively, p<0.001). There was no significant association between the second-phase of viral-decline and ALT normalization rate and, for a given level of viral reduction, ALT-normalization was more profound in patients receiving DAA, and NS5A in particular, than TVR+PR. Conclusions Our data support a process of HCV-clearance by all-DAA regimens potentiated by NS5A-inhibitor, and less relying upon hepatocyte death than IFN-containing regimens. This may underline a process of “cell-cure” by DAAs, leading to a fast improvement of liver homeostasis. PMID:28545127

Chronic hepatitis B: Virology, natural history, current management and a glimpse at future opportunities.

PubMed

Gish, Robert G; Given, Bruce D; Lai, Ching-Lung; Locarnini, Stephen A; Lau, Johnson Y N; Lewis, David L; Schluep, Thomas

2015-09-01

The host immune system plays an important role in chronic hepatitis B (CHB), both in viral clearance and hepatocellular damage. Advances in our understanding of the natural history of the disease have led to redefining the major phases of infection, with the "high replicative, low inflammatory" phase now replacing what was formerly termed the "immune tolerant" phase, and the "nonreplicative phase" replacing what was formerly termed the "inactive carrier" phase. As opposed to the earlier view that HBV establishes chronic infection by exploiting the immaturity of the neonate's immune system, new findings on trained immunity show that the host is already somewhat "matured" following birth, and is actually very capable of responding immunologically, potentially altering future hepatitis B treatment strategies. While existing therapies are effective in reducing viral load and necroinflammation, often restoring the patient to near-normal health, they do not lead to a cure except in very rare cases and, in many patients, viremia rebounds after cessation of treatment. Researchers are now challenged to devise therapies that will eliminate infection, with a particular focus on eliminating the persistence of viral cccDNA in the nuclei of hepatocytes. In the context of chronic hepatitis B, new definitions of 'cure' are emerging, such as 'functional' and 'virological' cure, defined by stable off-therapy suppression of viremia and antigenemia, and the normalization of serum ALT and other liver-related laboratory tests. Continued advances in the understanding of the complex biology of chronic hepatitis B have resulted in the development of new, experimental therapies targeting viral and host factors and pathways previously not accessible to therapy, approaches which may lead to virological cures in the near term and functional cures upon long term follow-up. This article forms part of a symposium in Antiviral Research on "An unfinished story: from the discovery of the Australia antigen to the development of new curative therapies for hepatitis B." Copyright © 2015 Elsevier B.V. All rights reserved.

RIG-I-like receptor regulation in virus infection and immunity

PubMed Central

Chan, Ying Kai; Gack, Michaela U

2016-01-01

Mammalian cells have the intrinsic capacity to detect viral pathogens and to initiate an antiviral response that is characterized by the induction of interferons (IFNs) and proinflammatory cytokines. A delicate regulation of the signaling pathways that lead to cytokine production is needed to ensure effective clearance of the virus, while preventing tissue damage caused by excessive cytokine release. Here, we focus on the mechanisms that modulate the signal transduction triggered by RIG-I-like receptors (RLRs) and their adaptor protein MAVS, key components of the host machinery for sensing foreign RNA. Specifically, we summarize recent advances in understanding how RLR signaling is regulated by posttranslational and posttranscriptional mechanisms, microRNAs (miRNAs) and autophagy. We further discuss how viruses target these regulatory mechanisms for immune evasion. PMID:25644461

The susceptible-infected-recovered (SIR) model for viral marketing

NASA Astrophysics Data System (ADS)

Ismail, Siti Suhaila; Akil, Ku Azlina Ku; Chulan, Majdah; Sharif, Noorzila

2017-11-01

Viral marketing is a marketing strategy utilizes social media to spread information about a product or services provided. It is the most powerful way to share information in a short amount of time. The objective of this study is to investigate the dynamic of viral marketing within a time duration in the point of view of mathematics. This study used the epidemiological model known as Susceptible-Infected-Recovered (SIR). The model consists of a system of three differential equations with three state variables namely susceptible (S), infected (I) and recovered (R). It considers a case of SIR model with demography. Numerical experiments have been performed. The results show that viral marketing reaches its peak within two days. The online messages shared will become higher if the initial number of the infected individual has been increased.

Hepatitis C Virus: Viral Quasispecies and Genotypes

PubMed Central

Tsukiyama-Kohara, Kyoko; Kohara, Michinori

2017-01-01

Hepatitis C virus (HCV) mainly replicates in the cytoplasm, where it easily establishes persistent infection, resulting in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Due to its high rate of mutation, HCV forms viral quasispecies, categorized based on the highly variable regions in the envelope protein and nonstructural 5A protein. HCV possesses seven major genotypes, among which genotype 1 is the most prevalent globally. The distribution of HCV genotypes varies based on geography, and each genotype has a different sensitivity to interferon treatment. Recently-developed direct-acting antivirals (DAAs), which target viral proteases or polymerases, mediate drastically better antiviral effects than previous therapeutics. Although treatment with DAAs has led to the development of drug-resistant HCV mutants, the most recently approved DAAs show improved pan-genomic activity, with a higher barrier to viral resistance. PMID:29271914

Exposure to Fentanyl After Transdermal Patch Administration for Cancer Pain Management.

PubMed

Bista, Sudeep R; Haywood, Alison; Hardy, Janet; Norris, Ross; Hennig, Stefanie

2016-06-01

This study aimed to describe exposure after fentanyl transdermal patch administration in patients with advanced cancer to quantify variability around the exposure. Patients (n  =  56) with advanced cancer who received transdermal fentanyl (Durogesic®; median dose, 50 μg/h; range, 12-200 μg/h) provided venous blood samples (n  =  163) at various times (0.5-72 hours) during several patch application intervals. Plasma fentanyl concentration was determined (median, 0.9 μg/L; range, 0.04-9.7 μg/L) by high-performance liquid chromatography coupled to tandem mass spectrometry. Pharmacokinetic analysis was performed using nonlinear mixed-effects modeling with NONMEM. A 1-compartment distribution model with first-order absorption and elimination described fentanyl exposure after transdermal patch administration. Fentanyl apparent clearance (between-subject variability [BSV], %) was estimated at 122 L/h/70 kg and 38.5%, respectively. The absorption rate constant was 0.013 h(-1) . Between-occasion variability on apparent clearance was 22.0%, which was lower than BSV, suggesting predictable exposure within the same patient and justifying therapeutic drug monitoring. Except for weight-based dosing, no other patient characteristic could be identified to guide initial fentanyl dose selection in patients with advanced cancer. © 2015, The American College of Clinical Pharmacology.

CYP2B6*6 allele and age substantially reduce steady-state ketamine clearance in chronic pain patients: impact on adverse effects

PubMed Central

Li, Yibai; Jackson, Kate A; Slon, Barry; Hardy, Janet R; Franco, Michael; William, Leeroy; Poon, Peter; Coller, Janet K; Hutchinson, Mark R; Currow, David C; Somogyi, Andrew A

2015-01-01

Aims Ketamine analgesia is limited by low intrinsic efficacy compounded by large interindividual variability in drug responses, possibly due to the heterogeneity in drug concentration. The CYP2B6*6 allele is associated with substantially reduced ketamine metabolism in vitro and, therefore, may affect ketamine clearance. Our aims were to examine the impact of the CYP2B6*6 allele on ketamine plasma clearance and on adverse effects in chronic pain patients. Methods CYP2B6 genotypes were identified in 49 chronic pain patients who received 24 h continuous subcutaneous infusions of ketamine. Steady-state plasma concentrations of ketamine (Css,k) and norketamine (Css,nk) were determined using HPLC. Results The median plasma clearance of ketamine after 100 mg 24 h–1 dose was significantly lower in patients with the CYP2B6*6/*6 (21.6 l h–1) and CYP2B6*1/*6 (40.6 l h–1) genotypes compared with patients with the CYP2B6*1/*1 genotype (68.1 l h–1, P < 0.001). The ketamine : norketamine plasma metabolic ratio was significantly higher in patients with the CYP2B6*6/*6 genotype than in those with the CYP2B6*1/*6 and the CYP2B6*1/*1 genotypes (P < 0.001). Patients who experienced adverse effects had lower plasma clearance (45.6 l h-1) than those who did not (52.6 l h-1, P = 0.04). The CYP2B6*6 genotype and age, and their combined impact explained 40%, 30% and 60% of the variation in Css,k, respectively. Similar results were observed after higher doses. Conclusions The CYP2B6*6 allele is associated with a substantial decrease in steady-state ketamine plasma clearance in chronic pain patients. The decreased clearance and resultant higher plasma concentrations may be associated with a higher incidence of ketamine adverse effects. PMID:25702819

CYP2B6*6 allele and age substantially reduce steady-state ketamine clearance in chronic pain patients: impact on adverse effects.

PubMed

Li, Yibai; Jackson, Kate A; Slon, Barry; Hardy, Janet R; Franco, Michael; William, Leeroy; Poon, Peter; Coller, Janet K; Hutchinson, Mark R; Currow, David C; Somogyi, Andrew A

2015-08-01

Ketamine analgesia is limited by low intrinsic efficacy compounded by large interindividual variability in drug responses, possibly due to the heterogeneity in drug concentration. The CYP2B6*6 allele is associated with substantially reduced ketamine metabolism in vitro and, therefore, may affect ketamine clearance. Our aims were to examine the impact of the CYP2B6*6 allele on ketamine plasma clearance and on adverse effects in chronic pain patients. CYP2B6 genotypes were identified in 49 chronic pain patients who received 24 h continuous subcutaneous infusions of ketamine. Steady-state plasma concentrations of ketamine (Css,k ) and norketamine (Css,nk ) were determined using HPLC. The median plasma clearance of ketamine after 100 mg 24 h(-1) dose was significantly lower in patients with the CYP2B6*6/*6 (21.6 l h(-1) ) and CYP2B6*1/*6 (40.6 l h(-1) ) genotypes compared with patients with the CYP2B6*1/*1 genotype (68.1 l h(-1) , P < 0.001). The ketamine : norketamine plasma metabolic ratio was significantly higher in patients with the CYP2B6*6/*6 genotype than in those with the CYP2B6*1/*6 and the CYP2B6*1/*1 genotypes (P < 0.001). Patients who experienced adverse effects had lower plasma clearance (45.6 l h(-1) ) than those who did not (52.6 l h(-1) , P = 0.04). The CYP2B6*6 genotype and age, and their combined impact explained 40%, 30% and 60% of the variation in Css,k , respectively. Similar results were observed after higher doses. The CYP2B6*6 allele is associated with a substantial decrease in steady-state ketamine plasma clearance in chronic pain patients. The decreased clearance and resultant higher plasma concentrations may be associated with a higher incidence of ketamine adverse effects. © 2015 The British Pharmacological Society.

Race, Gender, and Genetic Polymorphism Contribute to Variability in Acetaminophen Pharmacokinetics, Metabolism, and Protein-Adduct Concentrations in Healthy African-American and European-American Volunteers.

PubMed

Court, Michael H; Zhu, Zhaohui; Masse, Gina; Duan, Su X; James, Laura P; Harmatz, Jerold S; Greenblatt, David J

2017-09-01

Over 30 years ago, black Africans from Kenya and Ghana were shown to metabolize acetaminophen faster by glucuronidation and slower by oxidation compared with white Scottish Europeans. The objectives of this study were to determine whether similar differences exist between African-Americans and European-Americans, and to identify genetic polymorphisms that could explain these potential differences. Acetaminophen plasma pharmacokinetics and partial urinary metabolite clearances via glucuronidation, sulfation, and oxidation were determined in healthy African-Americans (18 men, 23 women) and European-Americans (34 men, 20 women) following a 1-g oral dose. There were no differences in acetaminophen total plasma, glucuronidation, or sulfation clearance values between African-Americans and European-Americans. However, median oxidation clearance was 37% lower in African-Americans versus European-Americans (0.57 versus 0.90 ml/min per kilogram; P = 0.0001). Although acetaminophen total or metabolite clearance values were not different between genders, shorter plasma half-life values (by 11-14%; P < 0.01) were observed for acetaminophen, acetaminophen glucuronide, and acetaminophen sulfate in women versus men. The UGT2B15*2 polymorphism was associated with variant-allele-number proportional reductions in acetaminophen total clearance (by 15-27%; P < 0.001) and glucuronidation partial clearance (by 23-48%; P < 0.001). UGT2B15 *2/*2 genotype subjects also showed higher acetaminophen protein-adduct concentrations than *1/*2 (by 42%; P = 0.003) and *1/*1 (by 41%; P = 0.003) individuals. Finally, CYP2E1 *1D/*1D genotype African-Americans had lower oxidation clearance than *1C/*1D (by 42%; P = 0.041) and *1C/*1C (by 44%; P = 0.048) African-Americans. Consequently, African-Americans oxidize acetaminophen more slowly than European-Americans, which may be partially explained by the CYP2E1*1D polymorphism. UGT2B15*2 influences acetaminophen pharmacokinetics in both African-Americans and European-Americans. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Immunological aspects of Giardia infections

PubMed Central

Heyworth, Martin F.

2014-01-01

Immunodeficiency, particularly antibody deficiency, predisposes to increased intensity and persistence of Giardia infections. Giardia-infected immunocompetent hosts produce serum and intestinal antibodies against Giardia trophozoites. The number of Giardia muris trophozoites, in mice with G. muris infection, is reduced by intra-duodenal administration of anti-G. muris antibody. Giardia intestinalis antigens that are recognised by human anti-trophozoite antibodies include variable (variant-specific) and invariant proteins. Nitric oxide (NO) appears to contribute to host clearance of Giardia trophozoites. Arginine is a precursor of NO and is metabolised by Giardia trophozoites, possibly reducing its availability for generation of NO by the host. Work with mice suggests that T lymphocytes and interleukin-6 (IL-6) contribute to clearance of Giardia infection via mechanisms independent of antibodies. PMID:25347704

Analysis of hepatitis B virus preS1 variability and prevalence of the rs2296651 polymorphism in a Spanish population

PubMed Central

Casillas, Rosario; Tabernero, David; Gregori, Josep; Belmonte, Irene; Cortese, Maria Francesca; González, Carolina; Riveiro-Barciela, Mar; López, Rosa Maria; Quer, Josep; Esteban, Rafael; Buti, Maria; Rodríguez-Frías, Francisco

2018-01-01

AIM To determine the variability/conservation of the domain of hepatitis B virus (HBV) preS1 region that interacts with sodium-taurocholate cotransporting polypeptide (hereafter, NTCP-interacting domain) and the prevalence of the rs2296651 polymorphism (S267F, NTCP variant) in a Spanish population. METHODS Serum samples from 246 individuals were included and divided into 3 groups: patients with chronic HBV infection (CHB) (n = 41, 73% Caucasians), patients with resolved HBV infection (n = 100, 100% Caucasians) and an HBV-uninfected control group (n = 105, 100% Caucasians). Variability/conservation of the amino acid (aa) sequences of the NTCP-interacting domain, (aa 2-48 in viral genotype D) and a highly conserved preS1 domain associated with virion morphogenesis (aa 92-103 in viral genotype D) were analyzed by next-generation sequencing and compared in 18 CHB patients with viremia > 4 log IU/mL. The rs2296651 polymorphism was determined in all individuals in all 3 groups using an in-house real-time PCR melting curve analysis. RESULTS The HBV preS1 NTCP-interacting domain showed a high degree of conservation among the examined viral genomes especially between aa 9 and 21 (in the genotype D consensus sequence). As compared with the virion morphogenesis domain, the NTCP-interacting domain had a smaller proportion of HBV genotype-unrelated changes comprising > 1% of the quasispecies (25.5% vs 31.8%), but a larger proportion of genotype-associated viral polymorphisms (34% vs 27.3%), according to consensus sequences from GenBank patterns of HBV genotypes A to H. Variation/conservation in both domains depended on viral genotype, with genotype C being the most highly conserved and genotype E the most variable (limited finding, only 2 genotype E included). Of note, proline residues were highly conserved in both domains, and serine residues showed changes only to threonine or tyrosine in the virion morphogenesis domain. The rs2296651 polymorphism was not detected in any participant. CONCLUSION In our CHB population, the NTCP-interacting domain was highly conserved, particularly the proline residues and essential amino acids related with the NTCP interaction, and the prevalence of rs2296651 was low/null. PMID:29456407

Determination of a quantitative relationship between hepatic CYP3A5*1/*3 and CYP3A4 expression for use in the prediction of metabolic clearance in virtual populations.

PubMed

Barter, Z E; Perrett, H F; Yeo, K Rowland; Allorge, D; Lennard, M S; Rostami-Hodjegan, A

2010-11-01

The creation of virtual populations allows the estimation of pharmacokinetic parameters, such as metabolic clearance in extreme individuals rather than the 'average human'. Prediction of variability in metabolic clearance within genetically diverse populations relies on understanding the covariation in the expression of enzymes. A number of statistically significant positive correlations have been observed in the hepatic expression of cytochrome P450 drug metabolising enzymes. However, these rarely provided a quantitative description of the relationships which is required in creating virtual populations. Collation of data from 40 human liver microsomal samples in the current study indicated a significant positive relationship between hepatic microsomal CYP3A5*1/*3 and CYP3A4 content. Having developed a model describing the relationship between hepatic CYP3A4 and CYP3A5*1/*3, the Simcyp Population-based Simulator(®) was used to investigate the consequences of either incorporating or ignoring the relationship between the two enzymes on estimates of drug clearance. Simulations indicated that for a compound with greater metabolism by CYP3A5 than CYP3A4, such as tacrolimus, incorporation of the correlation between CYP3A4 and CYP3A5 does have an impact on the prediction of oral clearance. Failure to consider the relationship between CYP3A4 and CYP3A5 when creating the virtual population led to a 32% lower estimate of oral clearance in individuals possessing both the CYP3A5*1/*3 genotype and high basal concentrations of CYP3A4. Potential clinical implications may include an inadequate dose estimation during clinical study design, the consequences of which may include organ rejection in transplant recipients using immunosuppressants such as tacrolimus or toxicity due to elevated concentrations of circulating metabolites. Copyright © 2010 John Wiley & Sons, Ltd.

Population pharmacokinetics of unbound hydrocortisone in critically ill neonates and infants with vasopressor-resistant hypotension.

PubMed

Vezina, Heather E; Ng, Chee M; Vazquez, Delia M; Barks, John D; Bhatt-Mehta, Varsha

2014-07-01

To determine the population pharmacokinetics of unbound hydrocortisone in critically ill neonates and infants receiving IV hydrocortisone for treatment of vasopressor-resistant hypotension and to identify patient-specific sources of pharmacokinetic variability. Prospective observational cohort study. Level 3 neonatal ICU. Sixty-two critically ill neonates and infants receiving IV hydrocortisone as part of standard of care for the treatment of vasopressor-resistant hypotension: median gestational age 28 weeks (range, 23-41), median weight 1.2 kg (range, 0.5-4.4), and 29 females. None. Unbound baseline cortisol and postdose hydrocortisone concentrations measured from blood samples being drawn for routine laboratory tests. A one-compartment model best described the data. Allometric weight and postmenstrual age were significant covariates on unbound hydrocortisone clearance and volume of distribution. Final population estimates for clearance, volume of distribution, and baseline cortisol concentration were 20.2 L/hr, 244 L, and 1.37 ng/mL, respectively. Using the median weight and postmenstrual age of our subjects (i.e., 1.2 kg and 28 wk) in the final model, the typical unbound hydrocortisone clearance and volume of distribution were 1.0 L/hr and 4.2 L, respectively. The typical half-life for unbound hydrocortisone was 2.9 hours. A sharp and continuous increase in unbound hydrocortisone clearance was observed at 35 weeks postmenstrual age. We report the first pharmacokinetic data for unbound hydrocortisone, the pharmacologically active moiety, in critically ill neonates and infants with vasopressor-resistant hypotension. Unbound hydrocortisone clearance increased with body weight and was faster in children with an older postmenstrual age. Unbound hydrocortisone clearance increased sharply at 35 weeks postmenstrual age and continued to mature thereafter. This study lays the groundwork for evaluating unbound hydrocortisone exposure-response relationships and drawing definitive conclusions about the dosing of IV hydrocortisone in critically ill neonates and infants with vasopressor-resistant hypotension.

Effect of footwear on minimum foot clearance, heel slippage and spatiotemporal measures of gait in older women.

PubMed

Davis, Annette M; Galna, Brook; Murphy, Anna T; Williams, Cylie M; Haines, Terry P

2016-02-01

Footwear has been implicated as a factor in falls, which is a major issue affecting the health of older adults. This study investigated the effect of footwear with dorsal fixation, slippers and bare feet on minimum foot clearance, heel slippage and spatiotemporal variables of gait in community dwelling older women. Thirty women participated (mean age (SD) 69.1 (5.1) years) in a gait assessment using the GaitRITE and Vicon 612 motion analysis system. Conditions included footwear with dorsal fixation, slippers or bare feet. Footwear with dorsal fixation resulted in improved minimum foot clearance compared to the slippers and bare feet conditions and less heel slippage than slippers and an increase in double support. These features lend weight to the argument that older women should be supported to make footwear choices with optimal fitting features including dorsal fixation. Recommendations of particular styles and features of footwear may assist during falls prevention education to reduce the incidence of foot trips and falls. Copyright © 2015 Elsevier B.V. All rights reserved.

Relationship between inflammation and infliximab pharmacokinetics in rheumatoid arthritis

PubMed Central

Ternant, David; Ducourau, Emilie; Perdriger, Aleth; Corondan, Anca; Le Goff, Benoît; Devauchelle-Pensec, Valérie; Solau-Gervais, Elisabeth; Watier, Hervé; Goupille, Philippe; Paintaud, Gilles; Mulleman, Denis

2014-01-01

Aims Infliximab, an anti-tumour necrosis factor-α monoclonal antibody, is indicated in rheumatoid arthritis (RA). Our objective was to evaluate the influence of the sources of infliximab pharmacokinetic variability in RA. Methods Eighty-four patients treated with infliximab for RA were included in a prospective noncomparative study. They were analysed between two consecutive infliximab infusions. Infliximab concentrations were measured before the infusion, 2 h, 1 and 4 weeks after the infusion and immediately before the next infusion. Infliximab concentrations were described using a two-compartment population pharmacokinetic model. Results The mean (interindividual standard deviation) estimated central volume of distribution was 2.3 l (36%) and systemic clearance was 0.019 l h−1 (37%). The central volume of distribution increased with bodyweight; it was doubled between 50 and 90 kg. Systemic clearance increased with pre-infusion C-reactive protein concentration by 20%, varying from 3 to 14 mg l−1, and was decreased by 30% when methotrexate was coadministered. Conclusions The influence of methotrexate and inflammation on infliximab clearance suggests that individual adjustment of infliximab doses according to disease activity may be useful in RA. PMID:24354889

Decreased HIV diversity after allogeneic stem cell transplantation of an HIV-1 infected patient: a case report

PubMed Central

2010-01-01

The human immunodeficiency virus type 1 (HIV-1) coreceptor use and viral evolution were analyzed in blood samples from an HIV-1 infected patient undergoing allogeneic stem cell transplantation (SCT). Coreceptor use was predicted in silico from sequence data obtained from the third variable loop region of the viral envelope gene with two software tools. Viral diversity and evolution was evaluated on the same samples by Bayesian inference and maximum likelihood methods. In addition, phenotypic analysis was done by comparison of viral growth in peripheral blood mononuclear cells and in a CCR5 (R5)-deficient T-cell line which was controlled by a reporter assay confirming viral tropism. In silico coreceptor predictions did not match experimental determinations that showed a consistent R5 tropism. Anti-HIV directed antibodies could be detected before and after the SCT. These preexisting antibodies did not prevent viral rebound after the interruption of antiretroviral therapy during the SCT. Eventually, transplantation and readministration of anti-retroviral drugs lead to sustained increase in CD4 counts and decreased viral load to undetectable levels. Unexpectedly, viral diversity decreased after successful SCT. Our data evidence that only R5-tropic virus was found in the patient before and after transplantation. Therefore, blocking CCR5 receptor during stem cell transplantation might have had beneficial effects and this might apply to more patients undergoing allogeneic stem cell transplantation. Furthermore, we revealed a scenario of HIV-1 dynamic different from the commonly described ones. Analysis of viral evolution shows the decrease of viral diversity even during episodes with bursts in viral load. PMID:20210988

Clinical definition of respiratory viral infections in young children and potential bronchiolitis misclassification.

PubMed

Megalaa, Rosemary; Perez, Geovanny F; Kilaikode-Cheruveettara, Sasikumar; Kotwal, Nidhi; Rodriguez-Martinez, Carlos E; Nino, Gustavo

2018-01-01

Viral respiratory infections are often grouped as a single respiratory syndrome named 'viral bronchiolitis', independently of the viral etiology or individual risk factors. Clinical trials and guidelines have used a more stringent definition of viral bronchiolitis, including only the first episode of wheezing in children less than 12 months of age without concomitant respiratory comorbidities. There is increasing evidence suggesting that this definition is not being followed by pediatric care providers, but it is unclear to what extent viral respiratory infections are currently misclassified as viral bronchiolitis using standard definitions. We conducted a retrospective analysis of hospitalized young children (≤3 years) due to viral respiratory infections. Bronchiolitis was defined as the first wheezing episode less than 12 months of age. Demographic variables and comorbidities were obtained by electronic medical record review. The study comprised a total of 513 hospitalizations (n=453). Viral bronchiolitis was diagnosed in 144 admissions (28.1%). Notably, we identified that the majority of children diagnosed with bronchiolitis (63%) were misclassified as they had prior episodes of wheezing. Many children with bronchiolitis misclassification had significant comorbidities, including prematurity (51%), neuromuscular conditions (9.8%), and congenital heart disease (9.8%). Misclassification of bronchiolitis is a common problem that may lead to inappropriate management of viral respiratory infections in young children. A comprehensive approach that takes into consideration viral etiology and individual risk factors may lead to a more accurate clinical assessment of this condition and would potentially prevent bronchiolitis misclassification. © American Federation for Medical Research (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Kinetic parameters and renal clearances of plasma adenosine 3′,5′-monophosphate and guanosine 3′,5′-monophosphate in man

PubMed Central

Broadus, Arthur E.; Kaminsky, Neil I.; Hardman, Joel G.; Sutherland, Earl W.; Liddle, Grant W.

1970-01-01

Kinetic parameters and the renal clearances of plasma adenosine 3′,5′-monophosphate (cyclic AMP) and guanosine 3′,5′-monophosphate (cyclic GMP) were evaluated in normal subjects using tritium-labeled cyclic nucleotides. Each tracer was administered both by single, rapid intravenous injection and by constant intravenous infusion, and the specific activities of the cyclic nucleotides in plasma and urine were determined. Both cyclic AMP and cyclic GMP were cleared from plasma by glomerular filtration. The kidney was found to add a variable quantity of endogenous cyclic AMP to the tubular urine, amounting to an average of approximately one-third of the total level of cyclic AMP excreted. Plasma was the source of virtually all of the cyclic GMP excreted. Plasma levels of the cyclic nucleotides appeared to be in dynamic steady state. The apparent volumes of distribution of both nucleotides exceeded extracellular fluid volume, averaging 27 and 38% of body weight for cyclic AMP and cyclic GMP, respectively. Plasma production rates ranged from 9 to 17 nmoles/min for cyclic AMP and from 7 to 13 nmoles/min for cyclic GMP. Plasma clearance rates averaged 668 ml/min for cyclic AMP and 855 ml/min for cyclic GMP. Approximately 85% of the elimination of the cyclic nucleotides from the circulation was due to extrarenal clearance. PMID:5480849

Tyk2 as a target for immune regulation in human viral/bacterial pneumonia.

PubMed

Berg, Johanna; Zscheppang, Katja; Fatykhova, Diana; Tönnies, Mario; Bauer, Torsten T; Schneider, Paul; Neudecker, Jens; Rückert, Jens C; Eggeling, Stephan; Schimek, Maria; Gruber, Achim D; Suttorp, Norbert; Hippenstiel, Stefan; Hocke, Andreas C

2017-07-01

The severity and lethality of influenza A virus (IAV) infections is frequently aggravated by secondary bacterial pneumonia. However, the mechanisms in human lung tissue that provoke this increase in fatality are unknown and therapeutic immune modulatory options are lacking.We established a human lung ex vivo co-infection model to investigate innate immune related mechanisms contributing to the susceptibility of secondary pneumococcal pneumonia.We revealed that type I and III interferon (IFN) inhibits Streptococcus pneumoniae -induced interleukin (IL)-1β release. The lack of IL-1β resulted in the repression of bacterially induced granulocyte-macrophage colony-stimulating factor (GM-CSF) liberation. Specific inhibition of IFN receptor I and III-associated tyrosine kinase 2 (Tyk2) completely restored the S. pneumoniae -induced IL-1β-GM-CSF axis, leading to a reduction of bacterial growth. A preceding IAV infection of the human alveolus leads to a type I and III IFN-dependent blockade of the early cytokines IL-1β and GM-CSF, which are key for orchestrating an adequate innate immune response against bacteria. Their virally induced suppression may result in impaired bacterial clearance and alveolar repair.Pharmacological inhibition of Tyk2 might be a new treatment option to sustain beneficial endogenous GM-CSF levels in IAV-associated secondary bacterial pneumonia. Copyright ©ERS 2017.

RSV-encoded NS2 promotes epithelial cell shedding and distal airway obstruction

PubMed Central

Liesman, Rachael M.; Buchholz, Ursula J.; Luongo, Cindy L.; Yang, Lijuan; Proia, Alan D.; DeVincenzo, John P.; Collins, Peter L.; Pickles, Raymond J.

2014-01-01

Respiratory syncytial virus (RSV) infection is the major cause of bronchiolitis in young children. The factors that contribute to the increased propensity of RSV-induced distal airway disease compared with other commonly encountered respiratory viruses remain unclear. Here, we identified the RSV-encoded nonstructural 2 (NS2) protein as a viral genetic determinant for initiating RSV-induced distal airway obstruction. Infection of human cartilaginous airway epithelium (HAE) and a hamster model of disease with recombinant respiratory viruses revealed that NS2 promotes shedding of infected epithelial cells, resulting in two consequences of virus infection. First, epithelial cell shedding accelerated the reduction of virus titers, presumably by clearing virus-infected cells from airway mucosa. Second, epithelial cells shedding into the narrow-diameter bronchiolar airway lumens resulted in rapid accumulation of detached, pleomorphic epithelial cells, leading to acute distal airway obstruction. Together, these data indicate that RSV infection of the airway epithelium, via the action of NS2, promotes epithelial cell shedding, which not only accelerates viral clearance but also contributes to acute obstruction of the distal airways. Our results identify RSV NS2 as a contributing factor for the enhanced propensity of RSV to cause severe airway disease in young children and suggest NS2 as a potential therapeutic target for reducing the severity of distal airway disease. PMID:24713657

Adjuvant Ciprofloxacin for Persistent BK Polyomavirus Infection in Kidney Transplant Recipients

PubMed Central

Chandran, Sindhu; Vagefi, Parsia A.

2014-01-01

Background. BK virus (BKV) infection is a common complication following kidney transplantation. Immunosuppression reduction is the cornerstone of treatment while adjuvant drugs have been tried in small uncontrolled studies. We sought to examine our center's experience with the use of ciprofloxacin in patients with persistent BKV infection. Methods. Retrospective evaluation of the effect of a 30-day ciprofloxacin course (250 mg twice daily) on BKV infection in kidney transplant recipients who had been diagnosed with BK viruria ≥106 copies/mL and viremia ≥500 copies/mL and in whom the infection did not resolve after immunosuppression reduction and/or treatment with other adjuvant agents. BKV in plasma and urine was evaluated after 3 months following treatment with ciprofloxacin. Results. Nine kidney transplant recipients received ciprofloxacin at a median of 130 days following the initial reduction in immunosuppression. Three patients showed complete viral clearance and another 3 had a ≥50% decrease in plasma viral load. No serious adverse events secondary to ciprofloxacin were reported and no grafts were lost due to BKV up to 1 year after treatment. Conclusion. Ciprofloxacin may be a useful therapy for persistent BKV infection despite conventional treatment. Randomized trials are required to evaluate the potential benefit of this adjuvant therapy. PMID:25349720

Transgenic Clustered Regularly Interspaced Short Palindromic Repeat/Cas9-Mediated Viral Gene Targeting for Antiviral Therapy of Bombyx mori Nucleopolyhedrovirus.

PubMed

Chen, Shuqing; Hou, Chengxiang; Bi, Honglun; Wang, Yueqiang; Xu, Jun; Li, Muwang; James, Anthony A; Huang, Yongping; Tan, Anjiang

2017-04-15

We developed a novel antiviral strategy by combining transposon-based transgenesis and the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) system for the direct cleavage of Bombyx mori nucleopolyhedrovirus (BmNPV) genome DNA to promote virus clearance in silkworms. We demonstrate that transgenic silkworms constitutively expressing Cas9 and guide RNAs targeting the BmNPV immediate early-1 ( ie-1 ) and me53 genes effectively induce target-specific cleavage and subsequent mutagenesis, especially large (∼7-kbp) segment deletions in BmNPV genomes, and thus exhibit robust suppression of BmNPV proliferation. Transgenic animals exhibited higher and inheritable resistance to BmNPV infection than wild-type animals. Our approach will not only contribute to modern sericulture but also shed light on future antiviral therapy. IMPORTANCE Pathogen genome targeting has shown its potential in antiviral research. However, transgenic CRISPR/Cas9 system-mediated viral genome targeting has not been reported as an antiviral strategy in a natural animal host of a virus. Our data provide an effective approach against BmNPV infection in a real-world biological system and demonstrate the potential of transgenic CRISPR/Cas9 systems in antiviral research in other species. Copyright © 2017 Chen et al.

Transgenic Clustered Regularly Interspaced Short Palindromic Repeat/Cas9-Mediated Viral Gene Targeting for Antiviral Therapy of Bombyx mori Nucleopolyhedrovirus

PubMed Central

Chen, Shuqing; Hou, Chengxiang; Bi, Honglun; Wang, Yueqiang; Xu, Jun; Li, Muwang; James, Anthony A.

2017-01-01

ABSTRACT We developed a novel antiviral strategy by combining transposon-based transgenesis and the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) system for the direct cleavage of Bombyx mori nucleopolyhedrovirus (BmNPV) genome DNA to promote virus clearance in silkworms. We demonstrate that transgenic silkworms constitutively expressing Cas9 and guide RNAs targeting the BmNPV immediate early-1 (ie-1) and me53 genes effectively induce target-specific cleavage and subsequent mutagenesis, especially large (∼7-kbp) segment deletions in BmNPV genomes, and thus exhibit robust suppression of BmNPV proliferation. Transgenic animals exhibited higher and inheritable resistance to BmNPV infection than wild-type animals. Our approach will not only contribute to modern sericulture but also shed light on future antiviral therapy. IMPORTANCE Pathogen genome targeting has shown its potential in antiviral research. However, transgenic CRISPR/Cas9 system-mediated viral genome targeting has not been reported as an antiviral strategy in a natural animal host of a virus. Our data provide an effective approach against BmNPV infection in a real-world biological system and demonstrate the potential of transgenic CRISPR/Cas9 systems in antiviral research in other species. PMID:28122981

Virus infection, antiviral immunity, and autoimmunity

PubMed Central

Getts, Daniel R.; Chastain, Emily M. L.; Terry, Rachael L.; Miller, Stephen D.

2014-01-01

Summary As a group of disorders, autoimmunity ranks as the third most prevalent cause of morbidity and mortality in the Western World. However, the etiology of most autoimmune diseases remains unknown. Although genetic linkage studies support a critical underlying role for genetics, the geographic distribution of these disorders as well as the low concordance rates in monozygotic twins suggest that a combination of other factors including environmental ones are involved. Virus infection is a primary factor that has been implicated in the initiation of autoimmune disease. Infection triggers a robust and usually well-coordinated immune response that is critical for viral clearance. However, in some instances, immune regulatory mechanisms may falter, culminating in the breakdown of self-tolerance, resulting in immune-mediated attack directed against both viral and self-antigens. Traditionally, cross-reactive T-cell recognition, known as molecular mimicry, as well as bystander T-cell activation, culminating in epitope spreading, have been the predominant mechanisms elucidated through which infection may culminate in an T-cell-mediated autoimmune response. However, other hypotheses including virus-induced decoy of the immune system also warrant discussion in regard to their potential for triggering autoimmunity. In this review, we discuss the mechanisms by which virus infection and antiviral immunity contribute to the development of autoimmunity. PMID:23947356

Immune protection against reinfection with nonprimate hepacivirus

PubMed Central

Pfaender, Stephanie; Walter, Stephanie; Grabski, Elena; Todt, Daniel; Bruening, Janina; Romero-Brey, Inés; Gather, Theresa; Brown, Richard J. P.; Hahn, Kerstin; Puff, Christina; Pfankuche, Vanessa M.; Hansmann, Florian; Postel, Alexander; Becher, Paul; Thiel, Volker; Kalinke, Ulrich; Wagner, Bettina; Bartenschlager, Ralf; Baumgärtner, Wolfgang; Feige, Karsten; Pietschmann, Thomas; Cavalleri, Jessika M. V.; Steinmann, Eike

2017-01-01

Hepatitis C virus (HCV) displays a restricted host species tropism and only humans and chimpanzees are susceptible to infection. A robust immunocompetent animal model is still lacking, hampering mechanistic analysis of virus pathogenesis, immune control, and prophylactic vaccine development. The closest homolog of HCV is the equine nonprimate hepacivirus (NPHV), which shares similar features with HCV and thus represents an animal model to study hepacivirus infections in their natural hosts. We aimed to dissect equine immune responses after experimental NPHV infection and conducted challenge experiments to investigate immune protection against secondary NPHV infections. Horses were i.v. injected with NPHV containing plasma. Flow cytometric analysis was used to monitor immune cell frequencies and activation status. All infected horses became viremic after 1 or 2 wk and viremia could be detected in two horses for several weeks followed by a delayed seroconversion and viral clearance. Histopathological examinations of liver biopsies revealed mild, periportally accentuated infiltrations of lymphocytes, macrophages, and plasma cells with some horses displaying subclinical signs of hepatitis. Following viral challenge, an activation of equine immune responses was observed. Importantly, after a primary NPHV infection, horses were protected against rechallenge with the homologous as well as a distinct isolate with only minute amounts of circulating virus being detectable. PMID:28275093

Factors in Variability of Serial Gabapentin Concentrations in Elderly Patients with Epilepsy.

PubMed

Conway, Jeannine M; Eberly, Lynn E; Collins, Joseph F; Macias, Flavia M; Ramsay, R Eugene; Leppik, Ilo E; Birnbaum, Angela K

2017-10-01

To characterize and quantify the variability of serial gabapentin concentrations in elderly patients with epilepsy. This study included 83 patients (age ≥ 60 yrs) from an 18-center randomized double-blind double-dummy parallel study from the Veterans Affairs Cooperative 428 Study. All patients were taking 1500 mg/day gabapentin. Within-person coefficient of variation (CV) in gabapentin concentrations, measured weekly to bimonthly for up to 52 weeks, then quarterly, was computed. Impact of patient characteristics on gabapentin concentrations (linear mixed model) and CV (linear regression) were estimated. A total of 482 gabapentin concentration measurements were available for analysis. Gabapentin concentrations and intrapatient CVs ranged from 0.5 to 22.6 μg/ml (mean 7.9 μg/ml, standard deviation [SD] 4.1 μg/ml) and 2% to 79% (mean 27.9%, SD 15.3%), respectively, across all visits. Intrapatient CV was higher by 7.3% for those with a body mass index of ≥ 30 kg/m 2 (coefficient = 7.3, p=0.04). CVs were on average 0.5% higher for each 1-unit higher CV in creatinine clearance (coefficient = 0.5, p=0.03) and 1.2% higher for each 1-hour longer mean time after dose (coefficient = 1.2, p=0.04). Substantial intrapatient variability in serial gabapentin concentration was noted in elderly patients with epilepsy. Creatinine clearance, time of sampling relative to dose, and obesity were found to be positively associated with variability. © 2017 Pharmacotherapy Publications, Inc.

CD4+ T cell count, HIV-1 viral loads and demographic variables of newly identified patients with HIV infection in Wuhan, China.

PubMed

Liu, Man-Qing; Tang, Li; Kong, Wen-Hua; Zhu, Ze-Rong; Peng, Jin-Song; Wang, Xia; Yao, Zhong-Zhao; Schilling, Robert; Zhou, Wang

2013-10-01

In China, the rate of human immunodeficiency virus (HIV) testing is increasing among men who have sex with men. The purpose of the present study was to describe HIV-related biomarkers and selected demographic variables of persons with newly diagnosed HIV/AIDS, among men who have sex with men in particular, in Wuhan China. Demographic indicators, and CD4+ T cell counts and HIV-1 viral load were collected from individuals newly identified as HIV-1 antibody positive during 2011. Of 176 enrolled patients, 132 (75.0%) were men who have sex with men. This group was significantly younger and had higher CD4+ T cell counts than patients who were likely infected through heterosexual contact. Most men who have sex with men (56.6%) were discovered by initiative investigation. Among heterosexual patients CD4+ T cell counts and HIV-1 viral load were significantly correlated; among the group of men who have sex with men, no such association was found. Copyright © 2013 Wiley Periodicals, Inc.

Population pharmacokinetics of caffeine in healthy male adults using mixed-effects models.

PubMed

Seng, K-Y; Fun, C-Y; Law, Y-L; Lim, W-M; Fan, W; Lim, C-L

2009-02-01

Caffeine has been shown to maintain or improve the performance of individuals, but its pharmacokinetic profile for Asians has not been well characterized. In this study, a population pharmacokinetic model for describing the pharmacokinetics of caffeine in Singapore males was developed. The data were also analysed using non-compartmental models. Data gathered from 59 male volunteers, who each ingested a single caffeine capsule in two clinical trials (3 or 5 mg/kg), were analysed via non-linear mixed-effects modelling. The participants' covariates, including age, body weight, and regularity of caffeinated-beverage consumption or smoking, were analysed in a stepwise fashion to identify their potential influence on caffeine pharmacokinetics. The final pharmacostatistical model was then subjected to stochastic simulation to predict the plasma concentrations of caffeine after oral (204, 340 and 476 mg) dosing regimens (repeated dosing every 6, 8 or 12 h) over a hypothetical 3-day period. The data were best described by a one-compartmental model with first-order absorption and first-order elimination. Smoking status was an influential covariate for clearance: clearance (mL/min) = 110*SMOKE + 114, where SMOKE was 0 and 1 for the non-smoker and the smoker respectively. Interoccasion variability was smaller compared to interindividual variability in clearance, volume and absorption rate (27% vs. 33%, 10% vs. 15% and 23% vs. 51% respectively). The extrapolated elimination half-lives of caffeine in the non-smokers and the smokers were 4.3 +/- 1.5 and 3.0 +/- 0.7 h respectively. Dosing simulations indicated that dosing regimens of 340 mg (repeated every 8 h) and 476 mg (repeated every 6 h) should achieve population-averaged caffeine concentrations within the reported beneficial range (4.5-9 microg/mL) in the non-smokers and the smokers respectively over 72 h. The population pharmacokinetic model satisfactorily described the disposition and variability of caffeine in the data. Mixed-effects modelling showed that the dose of caffeine depended on cigarette smoking status.

Excretion of moxidectin into breast milk and pharmacokinetics in healthy lactating women.

PubMed

Korth-Bradley, Joan M; Parks, Virginia; Chalon, Stephan; Gourley, Ian; Matschke, Kyle; Gossart, Sophie; Bryson, Philip; Fleckenstein, Lawrence

2011-11-01

Moxidectin, registered worldwide as a veterinary antiparasitic agent, is currently under development for humans for the treatment of onchocerciasis in collaboration with the World Health Organization. The objective of this study was to assess the pharmacokinetics of moxidectin in healthy lactating women, including the excretion into breast milk. Twelve women, ages 23 to 38 years, weighing 54 to 79 kg, all more than 5 months postpartum, were enrolled, following their plan to wean their infants and provision of informed consent. A single 8-mg, open-label dose was administered orally after consumption of a standard breakfast. Complete milk collection was done for approximately 28 days, and plasma samples were collected for 90 days. Moxidectin concentrations were measured by high-performance liquid chromatography (HPLC) with fluorescence detection, with a validated range of 0.08 to 120 ng/ml. Noncompartmental pharmacokinetic methods were used to find the following results: peak concentration in plasma (C(max)), 87 ± 25 ng/ml; time to C(max) (t(max)), 4.18 ± 1.59 h; terminal-phase elimination half-life (t(1/2)), 832 ± 321 h; total area under the concentration-time curve (AUC), 4,046 ± 1,796 ng · h/ml; apparent oral dose clearance (CL/F), 2.35 ± 1.07 l/h; ratio of CL/F to the terminal-phase disposition rate constant, λ(z) (Vλ(z)/F), 2,526 ± 772 liters; percentage of maternal dose excreted in milk, 0.701 ± 0.299%; absolute amount excreted in milk, 0.056 ± 0.024 mg; relative infant dose, 8.73 ± 3.17% of maternal dose assuming complete absorption; clearance in milk (CL(milk)), 0.016 ± 0.009 liter/h. Nine of 12 subjects reported adverse events, all of which were considered treatment emergent but not drug related and were mostly reported during the long outpatient period 8 to 90 days after dose administration. The most frequently reported adverse events were headache and nausea (n = 4), oropharyngeal pain (n = 2), rhinitis, viral pharyngitis, and viral upper respiratory tract infection (n = 2).

Detection of Pathogen Exposure in African Buffalo Using Non-Specific Markers of Inflammation

PubMed Central

Glidden, Caroline K.; Beechler, Brianna; Buss, Peter Erik; Charleston, Bryan; de Klerk-Lorist, Lin-Mari; Maree, Francois Frederick; Muller, Timothy; Pérez-Martin, Eva; Scott, Katherine Anne; van Schalkwyk, Ockert Louis; Jolles, Anna

2018-01-01

Detecting exposure to new or emerging pathogens is a critical challenge to protecting human, domestic animal, and wildlife health. Yet, current techniques to detect infections typically target known pathogens of humans or economically important animals. In the face of the current surge in infectious disease emergence, non-specific disease surveillance tools are urgently needed. Tracking common host immune responses indicative of recent infection may have potential as a non-specific diagnostic approach for disease surveillance. The challenge to immunologists is to identify the most promising markers, which ideally should be highly conserved across pathogens and host species, become upregulated rapidly and consistently in response to pathogen invasion, and remain elevated beyond clearance of infection. This study combined an infection experiment and a longitudinal observational study to evaluate the utility of non-specific markers of inflammation [NSMI; two acute phase proteins (haptoglobin and serum amyloid A), two pro-inflammatory cytokines (IFNγ and TNF-α)] as indicators of pathogen exposure in a wild mammalian species, African buffalo (Syncerus caffer). Specifically, in the experimental study, we asked (1) How quickly do buffalo mount NSMI responses upon challenge with an endemic pathogen, foot-and-mouth disease virus; (2) for how long do NSMI remain elevated after viral clearance and; (3) how pronounced is the difference between peak NSMI concentration and baseline NSMI concentration? In the longitudinal study, we asked (4) Are elevated NSMI associated with recent exposure to a suite of bacterial and viral respiratory pathogens in a wild population? Among the four NSMI that we tested, haptoglobin showed the strongest potential as a surveillance marker in African buffalo: concentrations quickly and consistently reached high levels in response to experimental infection, remaining elevated for almost a month. Moreover, elevated haptoglobin was indicative of recent exposure to two respiratory pathogens assessed in the longitudinal study. We hope this work motivates studies investigating suites of NSMI as indicators for pathogen exposure in a broader range of both pathogen and host species, potentially transforming how we track disease burden in natural populations. PMID:29375568

Clinical presentation and course of acute hepatitis C infection in HIV-infected patients.

PubMed

Luetkemeyer, Annie; Hare, C Bradley; Stansell, John; Tien, Phyllis C; Charlesbois, Edwin; Lum, Paula; Havlir, Diane; Peters, Marion

2006-01-01

Hepatitis C virus (HCV) has become a significant source of morbidity and mortality in HIV-infected patients. However, little is known about the clinical presentation and course of acute HCV infection in this population. This study reports the outcomes of acute HCV infection in 9 HIV-infected men. Sex with men was the only reported risk factor for HCV infection in 6 of the subjects. Clinical presentation of acute HCV ranged from incidentally discovered elevated transaminases to severe liver dysfunction requiring hospitalization. At the time of HCV diagnosis, 8 of 9 patients had CD4+ counts >250 cells/mm(3), and 6 had HIV viral loads of < or =5000 copies/mL. Eight patients were receiving antiretroviral therapy. Outcome of these acute HCV infections varied. Five patients experienced virologic clearance, 2 in whom virus cleared spontaneously and 3 who were treated with pegylated interferon and ribavirin. Four patients developed chronic infection, one of whom had a relapse during HCV treatment and 3 of whom were untreated. All 4 patients to whom HCV therapy was administered experienced significant anemia or neutropenia, necessitating dose reduction or support with growth factors. Prompt recognition of acute HCV infection may minimize antiretroviral treatment interruption and will allow early treatment, which may improve virologic clearance. Unexplained transaminase elevations in HIV-infected patients, including men who have sex with men, should trigger an evaluation for acute HCV infection.

Gag-Positive Reservoir Cells Are Susceptible to HIV-Specific Cytotoxic T Lymphocyte Mediated Clearance In Vitro and Can Be Detected In Vivo

PubMed Central

Graf, Erin H.; Pace, Matthew J.; Peterson, Bennett A.; Lynch, Lindsay J.; Chukwulebe, Steve B.; Mexas, Angela M.; Shaheen, Farida; Martin, Jeffrey N.; Deeks, Steven G.; Connors, Mark; Migueles, Stephen A.; O’Doherty, Una

2013-01-01

Resting CD4+ T cells infected with HIV persist in the presence of suppressive anti-viral therapy (ART) and are barriers to a cure. One potential curative approach, therapeutic vaccination, is fueled by recognition of the ability of a subset of elite controllers (EC) to control virus without therapy due to robust anti-HIV immune responses. Controllers have low levels of integrated HIV DNA and low levels of replication competent virus, suggesting a small reservoir. As our recent data indicates some reservoir cells can produce HIV proteins (termed GPR cells for Gag-positive reservoir cells), we hypothesized that a fraction of HIV-expressing resting CD4+ T cells could be efficiently targeted and cleared in individuals who control HIV via anti-HIV cytotoxic T lymphocytes (CTL). To test this we examined if superinfected resting CD4+ T cells from EC express HIV Gag without producing infectious virus and the susceptibility of these cells to CTL. We found that resting CD4+ T cells expressed HIV Gag and were cleared by autologous CD8+ T cells from EC. Importantly, we found the extent of CTL clearance in our in vitro assay correlates with in vivo reservoir size and that a population of Gag expressing resting CD4+ T cells exists in vivo in patients well controlled on therapy. PMID:23951263

Possible prevention of chronic hepatitis B by early interferon therapy.

PubMed

Trépo, C; Chemin, I; Petit, M A; Chossegros, P; Zoulim, F; Chevallier, P; Sepetjan, M

1990-01-01

A study is currently underway to investigate the efficacy of interferon therapy in patients with prolonged (greater than or equal to 10 weeks but less than 6 months) hepatitis B infection. To date, a total of 15 patients have been enrolled in the study and randomly assigned to receive either placebo for 24 weeks (n = 8) or interferon 5 million units subcutaneously 3 times a week for 24 weeks (n = 7), with follow up for 1 year. Thirteen patients have completed the follow-up period: seven patients in the placebo group and six in the treated group. Five of the six treated patients completely eradicated the infection during interferon therapy, with clearance of hepatitis B e and surface antigens, and seroconversion to antibody positivity in each case. Two of the eight placebo patients seroconverted during the placebo period. Clearance of hepatitis B e antigen was associated with a sudden rise in serum transaminase levels and an exacerbation of hepatitis, a phenomenon that has also been reported in chronic hepatitis B patients who have responded well to interferon therapy. Therapy was well tolerated in all cases. Our results suggest that interferon treatment of patients with prolonged hepatitis B infection may prevent progression to chronicity. If confirmed by further study, they should trigger more vigilant screening for patients with raised serum transaminase levels and viral markers of hepatitis B infection.

Host and Viral Factors in HIV-Mediated Bystander Apoptosis

PubMed Central

Garg, Himanshu; Joshi, Anjali

2017-01-01

Human immunodeficiency virus (HIV) infections lead to a progressive loss of CD4 T cells primarily via the process of apoptosis. With a limited number of infected cells and vastly disproportionate apoptosis in HIV infected patients, it is believed that apoptosis of uninfected bystander cells plays a significant role in this process. Disease progression in HIV infected individuals is highly variable suggesting that both host and viral factors may influence HIV mediated apoptosis. Amongst the viral factors, the role of Envelope (Env) glycoprotein in bystander apoptosis is well documented. Recent evidence on the variability in apoptosis induction by primary patient derived Envs underscores the role of Env glycoprotein in HIV disease. Amongst the host factors, the role of C-C Chemokine Receptor type 5 (CCR5), a coreceptor for HIV Env, is also becoming increasingly evident. Polymorphisms in the CCR5 gene and promoter affect CCR5 cell surface expression and correlate with both apoptosis and CD4 loss. Finally, chronic immune activation in HIV infections induces multiple defects in the immune system and has recently been shown to accelerate HIV Env mediated CD4 apoptosis. Consequently, those factors that affect CCR5 expression and/or immune activation in turn indirectly regulate HIV mediated apoptosis making this phenomenon both complex and multifactorial. This review explores the complex role of various host and viral factors in determining HIV mediated bystander apoptosis. PMID:28829402

Prediction of paraquat exposure and toxicity in clinically ill poisoned patients: a model based approach.

PubMed

Wunnapuk, Klintean; Mohammed, Fahim; Gawarammana, Indika; Liu, Xin; Verbeeck, Roger K; Buckley, Nicholas A; Roberts, Michael S; Musuamba, Flora T

2014-10-01

Paraquat poisoning is a medical problem in many parts of Asia and the Pacific. The mortality rate is extremely high as there is no effective treatment. We analyzed data collected during an ongoing cohort study on self-poisoning and from a randomized controlled trial assessing the efficacy of immunosuppressive therapy in hospitalized paraquat-intoxicated patients. The aim of this analysis was to characterize the toxicokinetics and toxicodynamics of paraquat in this population. A non-linear mixed effects approach was used to perform a toxicokinetic/toxicodynamic population analysis in a cohort of 78 patients. The paraquat plasma concentrations were best fitted by a two compartment toxicokinetic structural model with first order absorption and first order elimination. Changes in renal function were used for the assessment of paraquat toxicodynamics. The estimates of toxicokinetic parameters for the apparent clearance, the apparent volume of distribution and elimination half-life were 1.17 l h(-1) , 2.4 l kg(-1) and 87 h, respectively. Renal function, namely creatinine clearance, was the most significant covariate to explain between patient variability in paraquat clearance.This model suggested that a reduction in paraquat clearance occurred within 24 to 48 h after poison ingestion, and afterwards the clearance was constant over time. The model estimated that a paraquat concentration of 429 μg l(-1) caused 50% of maximum renal toxicity. The immunosuppressive therapy tested during this study was associated with only 8% improvement of renal function. The developed models may be useful as prognostic tools to predict patient outcome based on patient characteristics on admission and to assess drug effectiveness during antidote drug development. © 2014 The British Pharmacological Society.

Toxicity following methoxyflurane anaesthesia. IV. The role of obesity and the effect of low dose anaesthesia on fluoride metabolism and renal function.

PubMed

Samuelson, P N; Merin, R G; Taves, D R; Freeman, R B; Calimlim, J F; Kumazawa, T

1976-09-01

Seven obese and five normal weight patients were studied before, during and after one hour of methoxyflurane-nitrous oxide anaesthesia during peripheral surgical operations and compared with eight patients of normal weight anaesthetized with nitrous oxide-meperidine and d-tubocurare. Estimates were made of renal function, including serum and urinary electrolytes, osmolarity, uric acid, urea and creatinine. Renal clearances for the latter three substances were also calculated. Serum and urinary inorganic and organic fluoride concentrations were measured, as were renal clearances. This low dose methoxyflurane anaesthesia resulted only in a decrease in uric acid clearance among all the measures, when compared to the meperidine-nitrous oxide controls. The clearance of uric acid remained depressed for longer in the obese patients, but otherwise they did not differ from the normal weight patients. It is possible but not proven that depressed uric acid clearance may be related to the organic fluoride metabolite and an early indicator of methoxyflurane renal toxicity. The previously documented biotransformation of methoxyflurane was seen in this study. A double peak in serum inorganic fluoride was shown in all patients but one. Rather large differences in peak levels of serum inorganic fluoride occurred. The only significant difference between the obese and normal weight patients as far as fluoride metabolism was concerned was a greater variability in the serum inorganic fluoride levels in the obese patients. It would appear that the obese patient metabolizes methoxyflurane in a quantitatively if not qualitatively different fashion than the normal weight patient, perhaps because of fatty infiltration of the liver. Caution is advised in the use of methoxyflurane for more than 90 minutes of low concentration administration in view of the unpredictability of the biotransformation.

Errors in Computing the Normalized Protein Catabolic Rate due to Use of Single-pool Urea Kinetic Modeling or to Omission of the Residual Kidney Urea Clearance.

PubMed

Daugirdas, John T

2017-07-01

The protein catabolic rate normalized to body size (PCRn) often is computed in dialysis units to obtain information about protein ingestion. However, errors can manifest when inappropriate modeling methods are used. We used a variable volume 2-pool urea kinetic model to examine the percent errors in PCRn due to use of a 1-pool urea kinetic model or after omission of residual urea clearance (Kru). When a single-pool model was used, 2 sources of errors were identified. The first, dependent on the ratio of dialyzer urea clearance to urea distribution volume (K/V), resulted in a 7% inflation of the PCRn when K/V was in the range of 6 mL/min per L. A second, larger error appeared when Kt/V values were below 1.0 and was related to underestimation of urea distribution volume (due to overestimation of effective clearance) by the single-pool model. A previously reported prediction equation for PCRn was valid, but data suggest that it should be modified using 2-pool eKt/V and V coefficients instead of single-pool values. A third source of error, this one unrelated to use of a single-pool model, namely omission of Kru, was shown to result in an underestimation of PCRn, such that each ml/minute Kru per 35 L of V caused a 5.6% underestimate in PCRn. Marked overestimation of PCRn can result due to inappropriate use of a single-pool urea kinetic model, particularly when Kt/V <1.0 (as in short daily dialysis), or after omission of residual native kidney clearance. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Clearance Prediction Methodology Needs Fundamental Improvement: Trends Common to Rat and Human Hepatocytes/Microsomes and Implications for Experimental Methodology.

PubMed

Wood, F L; Houston, J B; Hallifax, D

2017-11-01

Although prediction of clearance using hepatocytes and liver microsomes has long played a decisive role in drug discovery, it is widely acknowledged that reliably accurate prediction is not yet achievable despite the predominance of hepatically cleared drugs. Physiologically mechanistic methodology tends to underpredict clearance by several fold, and empirical correction of this bias is confounded by imprecision across drugs. Understanding the causes of prediction uncertainty has been slow, possibly reflecting poor resolution of variables associated with donor source and experimental methods, particularly for the human situation. It has been reported that among published human hepatocyte predictions there was a tendency for underprediction to increase with increasing in vivo intrinsic clearance, suggesting an inherent limitation using this particular system. This implied an artifactual rate limitation in vitro, although preparative effects on cell stability and performance were not yet resolved from assay design limitations. Here, to resolve these issues further, we present an up-to-date and comprehensive examination of predictions from published rat as well as human studies (where n = 128 and 101 hepatocytes and n = 71 and 83 microsomes, respectively) to assess system performance more independently. We report a clear trend of increasing underprediction with increasing in vivo intrinsic clearance, which is similar both between species and between in vitro systems. Hence, prior concerns arising specifically from human in vitro systems may be unfounded and the focus of investigation in the future should be to minimize the potential in vitro assay limitations common to whole cells and subcellular fractions. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

A continuously variable beam-diameter, high-fluence, Q-switched Nd:YAG laser for tattoo removal: comparison of the maximum beam diameter to a standard 4-mm-diameter treatment beam.

PubMed

Bernstein, Eric F; Civiok, Jennifer M

2013-12-01

Laser beam diameter affects the depth of laser penetration. Q-switched lasers tend to have smaller maximum spot sizes than other dermatologic lasers, making beam diameter a potentially more significant factor in treatment outcomes. To compare the clinical effect of using the maximum-size treatment beam available for each delivered fluence during laser tattoo removal to a standard 4-mm-diameter treatment beam. Thirteen tattoos were treated in 12 subjects using a Q-switched Nd:YAG laser equipped with a treatment beam diameter that was adjustable in 1 mm increments and a setting that would enable the maximally achievable diameter ("MAX-ON" setting) with any fluence. Tattoos were randomly bisected and treated on one side with the MAX-ON setting and on the contralateral side with a standard 4-mm-diameter spot ("MAX-OFF" setting). Photographs were taken 8 weeks following each treatment and each half-tattoo was evaluated for clearance on a 10-point scale by physicians blinded to the treatment conditions. Tattoo clearance was greater on the side treated with the MAX-ON setting in a statistically significant manner following the 1st through 4th treatments, with the MAX-OFF treatment site approaching the clearance of the MAX-ON treatment site after the 5th and 6th treatments. This high-energy, Q-switched Nd:YAG laser with a continuously variable spot-size safely and effectively removes tattoos, with greater removal when using a larger spot-size. © 2013 Wiley Periodicals, Inc.

Sore throat in primary care project: a clinical score to diagnose viral sore throat.

PubMed

Mistik, Selcuk; Gokahmetoglu, Selma; Balci, Elcin; Onuk, Fahri A

2015-06-01

Viral agents cause the majority of sore throats. However, there is not currently a score to diagnose viral sore throat. The aims of this study were (i) to find the rate of bacterial and viral causes, (ii) to show the seasonal variations and (iii) to form a new scoring system to diagnose viral sore throat. A throat culture for group A beta haemolytic streptococci (GABHS) and a nasopharyngeal swab to detect 16 respiratory viruses were obtained from each patient. Over a period of 52 weeks, a total of 624 throat cultures and polymerase chain reaction analyses were performed. Logistic regression analysis was performed to find the clinical score. Viral infection was found in 277 patients (44.3%), and GABHS infection was found in 116 patients (18.5%). An infectious cause was found in 356 patients (57.1%). Rhinovirus was the most commonly detected infectious agent overall (highest in November, 34.5%), and the highest GABHS rate was in November (32.7%). Analysis of data provided a scoring system, called the Mistik Score, to diagnose viral sore throat. The predictive model for positive viral analysis included the following variables: absence of headache, stuffy nose, sneezing, temperature of ≥37.5°C on physical examination, and the absence of tonsillar exudate and/or swelling. The probability of a positive viral analysis for a score of 5 was 82.1%. The Mistik Score may be useful to diagnose viral sore throat. We suggest its use either alone or in combination with the Modified Centor Score. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Augmenting Influenza-Specific T Cell Memory Generation with a Natural Killer T Cell-Dependent Glycolipid-Peptide Vaccine.

PubMed

Anderson, Regan J; Li, Jasmine; Kedzierski, Lukasz; Compton, Benjamin J; Hayman, Colin M; Osmond, Taryn L; Tang, Ching-Wen; Farrand, Kathryn J; Koay, Hui-Fern; Almeida, Catarina Filipa Dos Santos Sa E; Holz, Lauren R; Williams, Geoffrey M; Brimble, Margaret A; Wang, Zhongfang; Koutsakos, Marios; Kedzierska, Katherine; Godfrey, Dale I; Hermans, Ian F; Turner, Stephen J; Painter, Gavin F

2017-11-17

The development of a universal vaccine for influenza A virus (IAV) that does not require seasonal modification is a long-standing health goal, particularly in the context of the increasing threat of new global pandemics. Vaccines that specifically induce T cell responses are of considerable interest because they can target viral proteins that are more likely to be shared between different virus strains and subtypes and hence provide effective cross-reactive IAV immunity. From a practical perspective, such vaccines should induce T cell responses with long-lasting memory, while also being simple to manufacture and cost-effective. Here we describe the synthesis and evaluation of a vaccine platform based on solid phase peptide synthesis and bio-orthogonal conjugation methodologies. The chemical approach involves covalently attaching synthetic long peptides from a virus-associated protein to a powerful adjuvant molecule, α-galactosylceramide (α-GalCer). Strain-promoted azide-alkyne cycloaddition is used as a simple and efficient method for conjugation, and pseudoproline methodology is used to increase the efficiency of the peptide synthesis. α-GalCer is a glycolipid that stimulates NKT cells, a population of lymphoid-resident immune cells that can provide potent stimulatory signals to antigen-presenting cells engaged in driving proliferation and differentiation of peptide-specific T cells. When used in mice, the vaccine induced T cell responses that provided effective prophylactic protection against IAV infection, with the speed of viral clearance greater than that seen from previous viral exposure. These findings are significant because the vaccines are highly defined, quick to synthesize, and easily characterized and are therefore appropriate for large scale affordable manufacture.

Changes in Fasting Plasma Glucose Levels with Ribavirin and Pegylated Interferon Treatment in Normal and Impaired Glucose Tolerant Patients with Chronic Hepatitis C

PubMed Central

Sarasombath, Ongkarn; Suwantarat, Nuntra; Tice, Alan D

2012-01-01

Background Patients with Hepatitis C Virus (HCV) infection have increased rates of glucose intolerance, and studies have shown the improvement of fasting plasma glucose (FPG) levels after clearance of HCV infection with standard ribavirin plus pegylated interferon treatment. The purpose of this study was to examine glycemic changes with standard HCV treatment in patients with impaired fasting glucose (IFG) and normal fasting glucose (NFG). Methods A retrospective study of FPG changes in HCV patients with IFG and NFG treated with standard HCV therapy was conducted. Baseline characteristics and viral responses were assessed; FPG levels before treatment, at the end of treatment, and more than one-month post treatment were compared. Results The mean FPG levels increased by 8.68 mg/dl at the end of treatment in the NFG group but decreased by 9.0 mg/dl in the IFG group, a statistically significant difference (P=0.019). The change in FPG levels remained significantly different after adjusting for weight change (P=0.009) and weight changes and initial weight (P=0.039). FPG change from baseline at more than one month after treatment were similar in both groups (P=0.145). The change in FPG levels was not associated with sustained viral response. Conclusions In HCV-infected patients, standard ribavirin plus pegylated interferon treatment reduced FPG levels in patients with IFG and increased FPG levels in NFG individuals; independent of initial weight, weight change, or viral response. Standard HCV treatment modulates fasting plasma glucose levels which supports the need for a prospective study to determine the clinical significance of this finding. PMID:22737650

West Nile virus nucleic acid persistence in whole blood months after clearance in plasma: implication for transfusion and transplantation safety

PubMed Central

Lanteri, Marion C.; Lee, Tzong-Hae; Wen, Li; Kaidarova, Zhanna; Bravo, Marjorie D.; Kiely, Nancy E.; Kamel, Hany T.; Tobler, Leslie H.; Norris, Philip J.; Busch, Michael P.

2014-01-01

BACKGROUND Previous reports of WNV RNA persistence in blood compartments have raised concerns around the remaining risk of WNV transfusion-transmission. This study characterized the dynamics of WNV viremia in blood compartments in a longitudinal cohort of 54 WNV-infected blood donors. STUDY DESIGN AND METHODS Blood samples were collected throughout the year after WNV RNA+ blood donation (index) and characterized for anti-WNV IgM and IgG antibodies and for WNV RNA by real-time reverse-transcription polymerase chain reaction. WNV viral loads were compared in plasma and whole blood samples and correlated with blood groups and clinical outcomes. RESULTS WNV RNA persisted in the red blood cell (RBC) compartment up to three months post-index in 42% of the donors. Donors with the highest WNV RNA levels in plasma at index maintained the highest WNV RNA levels in whole blood over the three months post-index. Blood group A donors maintained higher post-index WNV viral load in whole blood than blood group O individuals (P=0.027). Despite a trend for WNV RNA to persist longer in whole blood from symptomatic subjects, no significant association was found between WNV RNA levels in whole blood and disease outcome. CONCLUSION This study confirmed that WNV RNA persists in the RBC fraction in whole blood and further suggested that the level of persistence in whole blood may be a reflection of initial viral burden in plasma. The association with blood groups suggests that WNV adherence to RBCs may be mediated by molecules overrepresented at the surface of blood group A RBCs. PMID:24965017

What factors determine the severity of hepatitis A-related acute liver failure?

PubMed

Ajmera, V; Xia, G; Vaughan, G; Forbi, J C; Ganova-Raeva, L M; Khudyakov, Y; Opio, C K; Taylor, R; Restrepo, R; Munoz, S; Fontana, R J; Lee, W M

2011-07-01

The reason(s) that hepatitis A virus (HAV) infection may progress infrequently to acute liver failure are poorly understood. We examined host and viral factors in 29 consecutive adult patients with HAV-associated acute liver failure enrolled at 10 sites participating in the US ALF Study Group. Eighteen of twenty-four acute liver failure sera were PCR positive while six had no detectable virus. HAV genotype was determined using phylogenetic analysis and the full-length genome sequences of the HAV from a cute liver failure sera were compared to those from self-limited acute HAV cases selected from the CDC database. We found that rates of nucleotide substitution did not vary significantly between the liver failure and non-liver failure cases and there was no significant variation in amino acid sequences between the two groups. Four of 18 HAV isolates were sub-genotype IB, acquired from the same study site over a 3.5-year period. Sub-genotype IB was found more frequently among acute liver failure cases compared to the non-liver failure cases (chi-square test, P < 0.01). At another centre, a mother and her son presented with HAV and liver failure within 1 month of each other. Predictors of spontaneous survival included detectable serum HAV RNA, while age, gender, HAV genotype and nucleotide substitutions were not associated with outcome. The more frequent appearance of rapid viral clearance and its association with poor outcomes in acute liver failure as well as the finding of familial cases imply a possible host genetic predisposition that contributes to a fulminant course. Recurrent cases of the rare sub-genotype IB over several years at a single centre imply a community reservoir of infection and possible increased pathogenicity of certain infrequent viral genotypes. © 2010 Blackwell Publishing Ltd.

The Chinese medicine Kuan-Sin-Yin improves liver function in patients with chronic hepatitis C: A randomised and placebo-controlled trial.

PubMed

Liu, Chia-Yu; Ko, Pin-Hao; Yen, Hung-Rong; Cheng, Chen-Hung; Li, Yu-Hsien; Liao, Zih-Han; Hsu, Chung-Hua

2016-08-01

This study examined the effects of a traditional Chinese medicine decoction, Kuan-Sin-Yin (KSY), on patients with chronic hepatitis C (CHC) in a randomised and placebo-controlled clinical trial. This trial enrolled 70 subjects with CHC who were randomised into 2 groups each with 35 participants. In total, 29 participants in the therapeutic group took 100mL of the herbal decoction daily, whereas 28 in the control group took an herbal placebo with the same dose and frequency for the 6-week study. The primary outcomes were liver function and viral load. Secondary measurements included haematopoietic and biochemical profiles, safety parameters, and a quality of life survey. All measurements were collected at the beginning of the study and after 6 weeks. In within-group analysis, significant decreases of glutamate pyruvate transaminase (GPT) 31.7±75.2IU/L and glutamate oxaloacetate transaminase (GOT) 20.3±45.7IU/L were found in the KSY group (p=0.031 and 0.024, respectively). In the between-group analysis, KSY reduced serum GOT and GPT levels by more than 20IU/L (p=0.027 and 0.047, respectively). KSY also significantly decreased viral load by 0.3 log units (p=0.047). In addition, KSY significantly decreased serum triglyceride 16.9±27.5mg/dL (p=0.024). This study demonstrates that taking the KSY herbal decoction for 6 weeks improves liver function and serum triglyceride levels and is safe for patients with CHC. The potential long-term effects of KSY on lipid metabolism related hepatoprotection and viral clearance warrant further investigation. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

What factors determine the severity of hepatitis A-related acute liver failure?

PubMed Central

Ajmera, V.; Xia, G.; Vaughan, G.; Forbi, J. C.; Ganova-Raeva, L. M.; Khudyakov, Y.; Opio, C. K.; Taylor, R.; Restrepo, R.; Munoz, S.; Fontana, R. J.; Lee, W. M.

2016-01-01

SUMMARY The reason(s) that hepatitis A virus (HAV) infection may progress infrequently to acute liver failure are poorly understood. We examined host and viral factors in 29 consecutive adult patients with HAV-associated acute liver failure enrolled at 10 sites participating in the US ALF Study Group. Eighteen of twenty-four acute liver failure sera were PCR positive while six had no detectable virus. HAV genotype was determined using phylogenetic analysis and the full-length genome sequences of the HAV from a cute liver failure sera were compared to those from self-limited acute HAV cases selected from the CDC database. We found that rates of nucleotide substitution did not vary significantly between the liver failure and non-liver failure cases and there was no significant variation in amino acid sequences between the two groups. Four of 18 HAV isolates were subgenotype IB, acquired from the same study site over a 3.5-year period. Sub-genotype IB was found more frequently among acute liver failure cases compared to the non-liver failure cases (chi-square test, P < 0.01). At another centre, a mother and her son presented with HAV and liver failure within 1 month of each other. Predictors of spontaneous survival included detectable serum HAV RNA, while age, gender, HAV genotype and nucleotide substitutions were not associated with outcome. The more frequent appearance of rapid viral clearance and its association with poor outcomes in acute liver failure as well as the finding of familial cases imply a possible host genetic predisposition that contributes to a fulminant course. Recurrent cases of the rare subgenotype IB over several years at a single centre imply a community reservoir of infection and possible increased pathogenicity of certain infrequent viral genotypes. PMID:21143345

Attacking Postoperative Metastases using Perioperative Oncolytic Viruses and Viral Vaccines

PubMed Central

Tai, Lee-Hwa; Auer, Rebecca

2014-01-01

Surgical resection of solid primary malignancies is a mainstay of therapy for cancer patients. Despite being the most effective treatment for these tumors, cancer surgery has been associated with impaired metastatic clearance due to immunosuppression. In preclinical surgery models and human cancer patients, we and others have demonstrated a profound suppression of both natural killer (NK) and T cell function in the postoperative period and this plays a major role in the enhanced development of metastases following surgery. Oncolytic viruses (OV) were originally designed to selectively infect and replicate in tumors, with the primary objective of directly lysing cancer cells. It is becoming increasingly clear, however, that OV infection results in a profound inflammatory reaction within the tumor, initiating innate and adaptive immune responses against it that is critical for its therapeutic benefit. This anti-tumor immunity appears to be mediated predominantly by NK and cytotoxic T cells. In preclinical models, we found that preoperative OV prevents postoperative NK cell dysfunction and attenuates tumor dissemination. Due to theoretical safety concerns of administering live virus prior to surgery in cancer patients, we characterized safe, attenuated versions of OV, and viral vaccines that could stimulate NK cells and reduce metastases when administered in the perioperative period. In cancer patients, we observed that in vivo infusion with oncolytic vaccinia virus and ex vivo stimulation with viral vaccines promote NK cell activation. These preclinical studies provide a novel and clinically relevant setting for OV therapy. Our challenge is to identify safe and promising OV therapies that will activate NK and T cells in the perioperative period preventing the establishment of micrometastatic disease in cancer patients. PMID:25161958

Single-Cell Analysis Uncovers Extensive Biological Noise in Poliovirus Replication

PubMed Central

Schulte, Michael B.

2014-01-01

ABSTRACT Viral infections often begin with a very small number of initiating particles. Accordingly, the outcome of an infection is likely to be affected by variability in the initial molecular interactions between virus and host. In this study, we investigated the range of outcomes upon infection of single cells. We isolated individual cells infected with poliovirus at low or high multiplicities of infection (MOI) and measured viral genomic replication and infectious viral progeny in each cell. We first determined that at 7 h postinfection, the ratio of positive to negative strands in individual cells varies from 5:1 to more than 190:1, with and average of 20:1, suggesting a significant variability in RNA synthesis. We further found that while virus genome production is higher in cells infected at a high multiplicity, the production of infectious particles is largely independent of the number of viruses infecting each cell. Strikingly, by correlating RNA and particle production within individual infections, we uncovered a significant contribution of stochastic noise to the outcome of infection. At low MOI, stochastic influences appear as kinetic effects which are most critical at the initial steps in infection. At high MOI, stochastic influences appear to dictate the virus's ability to harness cellular resources. We conclude that biological noise is a critical determinant of the overall productivity of viral infections. The distinct nature of stochasticity in the outcome of infection by low and high numbers of viral particles may have important implications for our understanding of the determinants of successful viral infections. IMPORTANCE By correlating genome and particle production in single-cell infections, we elucidated sources of noise in viral infections. When a cell was infected by only a single infectious particle, variation in the kinetics of the initial steps of replication contributed significantly to the overall productivity of the infection. Additionally, variation in the distribution of subcellular resources impacted infections initiated by one or many infectious particles. We also observed that when a cell was infected with multiple particles, more genomes were produced, while particle production was hindered by an apparent cellular resource limit. Understanding variations in viral infections may illuminate the dynamics of infection and pathogenesis and has implications for virus adaptation and evolution. PMID:24648454

Conceptualization and design of a variable-gravity research facility

NASA Technical Reports Server (NTRS)

1987-01-01

The goal is to provide facilities for the study of the effects of variable-gravity levels in reducing the physiological stresses upon the humans of long-term stay time in zero-g. The designs studied include: twin-tethered two module system with a central despun module with docking port and winch gear; and rigid arm tube facility using shuttle external tanks. Topics examined included: despun central capsule configuration, docking clearances, EVA requirements, crew selection, crew scheduling, food supply and preparation, waste handling, leisure use, biomedical issues, and psycho-social issues.

Risk-managed production of bioactive recombinant proteins using a novel plant virus vector with a helper plant to complement viral systemic movement.

PubMed

Fukuzawa, Noriho; Ishihara, Takeaki; Itchoda, Noriko; Tabayashi, Noriko; Kataoka, Chiwa; Masuta, Chikara; Matsumura, Takeshi

2011-01-01

A plant viral vector has the potential to efficiently produce recombinant proteins at a low cost in a short period. Although recombinant proteins can be also produced by transgenic plants, a plant viral vector, if available, may be more convenient when urgent scale-up in production is needed. However, it is difficult to use a viral vector in open fields because of the risk of escape to the environment. In this study, we constructed a novel viral vector system using a movement-defective Cucumber mosaic virus (CMV) vector, which is theoretically localized in the inoculated cells but infects systemically only with the aid of the transgenic helper plant that complements viral movement, diminishing the risk of viral proliferation. Interestingly, the helper plant systemically infected with the vector gave strong cross-protection against challenge inoculation with wild-type CMVs. Using CMV strains belonging to two discrete CMV groups (subgroups I and II), we also improved the system to prevent recombination between the vector and the transgene transcript in the helper plant. We here demonstrate the expression of an anti-dioxin single chain variable fragment (DxscFv) and interleukin-1 receptor antagonist (IL1-Ra) in Nicotiana benthamiana by this viral vector confinement system, which is applicable for many useful high-quality recombinant proteins. © 2010 The Authors. Plant Biotechnology Journal © 2010 Society for Experimental Biology and Blackwell Publishing Ltd.

The Cockroft and Gault formula for estimation of creatinine clearance: a friendly deconstruction.

PubMed

Millar, J Alasdair

2012-02-24

To review the derivation of the Cockroft and Gault formula for estimating creatinine clearance from serum creatinine in a historical context. The derivation described by Cockroft and Gault was reviewed, and an alternative formula was sought using the data reported in the paper. Cockroft and Gault used 24 hour urine creatinine data expressed as mg/kg body weight and mathematical manipulation of a linear regression equation which introduced body weight as an independent variable into the formula. This involved a circular logic and may have been mathematically invalid. A more logical equation not containing body weight was derived from the data. The Cockcroft and Gault formula has been validated by long usage but the derivation appears logically insecure. Nevertheless, its role in estimating renal function at the bedside is established.

How to report and discuss ADME data in medicinal chemistry publications: in vitro data or in vivo extrapolations?

PubMed

Svennebring, Andreas M

2015-01-01

Early drug discovery projects often utilize data from ADME (absorption, distribution, metabolism, elimination) assays to benchmark data and guide discussion, rather than the predicted in vivo consequences of these data. Here, the two paradigms are compared, using evaluations of metabolic stability based on either microsomal clearance assay data or from the predicted in vivo hepatic clearance and half-life calculated through the combination of the venous well-stirred model and Øie-Tozer's model. The need for a shift in paradigm is presented, and its implications discussed. It is suggested that discussions about ADME data should revolve around potential clinical problems that are most likely to surface during the development phase, each benchmarked with a suitable variable derived from the assay data.

Immunological aspects of Giardia infections.

PubMed

Heyworth, Martin F

2014-01-01

Immunodeficiency, particularly antibody deficiency, predisposes to increased intensity and persistence of Giardia infections. Giardia-infected immunocompetent hosts produce serum and intestinal antibodies against Giardia trophozoites. The number of Giardia muris trophozoites, in mice with G. muris infection, is reduced by intra-duodenal administration of anti-G. muris antibody. Giardia intestinalis antigens that are recognised by human anti-trophozoite antibodies include variable (variant-specific) and invariant proteins. Nitric oxide (NO) appears to contribute to host clearance of Giardia trophozoites. Arginine is a precursor of NO and is metabolised by Giardia trophozoites, possibly reducing its availability for generation of NO by the host. Work with mice suggests that T lymphocytes and interleukin-6 (IL-6) contribute to clearance of Giardia infection via mechanisms independent of antibodies. © M.F. Heyworth, published by EDP Sciences, 2014.

RIG-I-like receptor regulation in virus infection and immunity.

PubMed

Chan, Ying Kai; Gack, Michaela U

2015-06-01

Mammalian cells have the intrinsic capacity to detect viral pathogens and to initiate an antiviral response that is characterized by the induction of interferons (IFNs) and proinflammatory cytokines. A delicate regulation of the signaling pathways that lead to cytokine production is needed to ensure effective clearance of the virus, while preventing tissue damage caused by excessive cytokine release. Here, we focus on the mechanisms that modulate the signal transduction triggered by RIG-I-like receptors (RLRs) and their adaptor protein MAVS, key components of the host machinery for sensing foreign RNA. Specifically, we summarize recent advances in understanding how RLR signaling is regulated by posttranslational and posttranscriptional mechanisms, microRNAs (miRNAs) and autophagy. We further discuss how viruses target these regulatory mechanisms for immune evasion. Copyright © 2015 Elsevier B.V. All rights reserved.

Ebola Virus Disease Is Characterized by Poor Activation and Reduced Levels of Circulating CD16+ Monocytes.

PubMed

Lüdtke, Anja; Ruibal, Paula; Becker-Ziaja, Beate; Rottstegge, Monika; Wozniak, David M; Cabeza-Cabrerizo, Mar; Thorenz, Anja; Weller, Romy; Kerber, Romy; Idoyaga, Juliana; Magassouba, N'Faly; Gabriel, Martin; Günther, Stephan; Oestereich, Lisa; Muñoz-Fontela, César

2016-10-15

A number of previous studies have identified antigen-presenting cells (APCs) as key targets of Ebola virus (EBOV), but the role of APCs in human Ebola virus disease (EVD) is not known. We have evaluated the phenotype and kinetics of monocytes, neutrophils, and dendritic cells (DCs) in peripheral blood of patients for whom EVD was diagnosed by the European Mobile Laboratory in Guinea. Acute EVD was characterized by reduced levels of circulating nonclassical CD16 + monocytes with a poor activation profile. In survivors, CD16 + monocytes were activated during recovery, coincident with viral clearance, suggesting an important role of this cell subset in EVD pathophysiology. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Clearance of hepatitis C viral RNA in cirrhotic patients with antiviral therapy.

PubMed

Ono, S K; da Silva, L C; Carrilho, F J; da Fonseca, L E; Mendes, L C; Madruga, C L; Farias, A de Q; Laudanna, A A

1996-01-01

Interferon is indicated in chronic infection by hepatitis C virus (HCV), however, cirrhosis has been reported as a bad response factor to the therapy. Fifteen cirrhotic patients with HCV, undergoing treatment with recombinant interferon-alpha, ribavirin and/or ursodeoxycholic acid were studied. They were followed-up and evaluated with dosages of alanine aminotransferase and HCV RNA investigation by PCR technique. Of the 15 cirrhotic patients, seven were negative for HCV RNA after antiviral treatment, however ALT was normal in only three of them. Of the eight patients who were not negative, two had normal ALT. Biochemical-virological discrepancy in the follow-up of the patients after antiviral treatment observed in this study has also been reported by other authors. These reports show that the criteria for response to the treatment is to be established.

Viral activity in two contrasting lake ecosystems.

PubMed

Bettarel, Yvan; Sime-Ngando, Télesphore; Amblard, Christian; Dolan, John

2004-05-01

For aquatic systems, especially freshwaters, there is little data on the long-term (i.e., >6-month period) and depth-related variability of viruses. In this study, we examined virus-induced mortality of heterotrophic bacteria over a 10-month period and throughout the water column in two lakes of the French Massif Central, the oligomesotrophic Lake Pavin and the eutrophic Lake Aydat. Concurrently, we estimated nonviral mortality through heterotrophic nanoflagellate and ciliate bacterivory. Overall, viral infection parameters were much less variable than bacterial production. We found that the frequency of visibly infected cells (FVIC), estimated using transmission electron microscopy, peaked in both lakes at the end of spring (May to June) and in early autumn (September to October). FVIC values were significantly higher in Lake Pavin (mean [M] = 1.6%) than in Lake Aydat (M = 1.1%), whereas the opposite trend was observed for burst sizes, which averaged 25.7 and 30.2 virus particles bacterium(-1), respectively. We detected no significant depth-related differences in FVIC or burst size. We found that in both lakes the removal of bacterial production by flagellate grazing (M(Pavin) = 37.7%, M(Aydat) = 18.5%) was nearly always more than the production removed by viral lysis (M(Pavin) = 16.2%, M(Aydat) = 19%) or ciliate grazing (M(Pavin) = 2.7%, M(Aydat) = 8.8%). However, at specific times and locations, viral lysis prevailed over protistan grazing, for example, in the anoxic hypolimnion of Lake Aydat. In addition, viral mortality represented a relatively constant mortality source in a bacterial community showing large variations in growth rate and subject to large variations in loss rates from grazers. Finally, although viruses did not represent the main agent of bacterial mortality, our data seem to show that their relative importance was higher in the less productive system.

Population pharmacokinetics of Rilpivirine in HIV-1-infected patients treated with the single-tablet regimen rilpivirine/tenofovir/emtricitabine.

PubMed

Néant, Nadège; Gattacceca, Florence; Lê, Minh Patrick; Yazdanpanah, Yazdan; Dhiver, Catherine; Bregigeon, Sylvie; Mokhtari, Saadia; Peytavin, Gilles; Tamalet, Catherine; Descamps, Diane; Lacarelle, Bruno; Solas, Caroline

2018-04-01

Rilpivirine, prescribed for the treatment of HIV infection, presents an important inter-individual pharmacokinetic variability. We aimed to determine population pharmacokinetic parameters of rilpivirine in adult HIV-infected patients and quantify their inter-individual variability. We conducted a multicenter, retrospective, and observational study in patients treated with the once-daily rilpivirine/tenofovir disoproxil fumarate/emtricitabine regimen. As part of routine therapeutic drug monitoring, rilpivirine concentrations were measured by UPLC-MS/MS. Population pharmacokinetic analysis was performed using NONMEM software. Once the compartmental and random effects models were selected, covariates were tested to explain the inter-individual variability in pharmacokinetic parameters. The final model qualification was performed by both statistical and graphical methods. We included 379 patients, resulting in the analysis of 779 rilpivirine plasma concentrations. Of the observed trough individual plasma concentrations, 24.4% were below the 50 ng/ml minimal effective concentration. A one-compartment model with first-order absorption best described the data. The estimated fixed effect for plasma apparent clearance and distribution volume were 9 L/h and 321 L, respectively, resulting in a half-life of 25.2 h. The common inter-individual variability for both parameters was 34.1% at both the first and the second occasions. The inter-individual variability of clearance was 30.3%. Our results showed a terminal half-life lower than reported and a high proportion of patients with suboptimal rilpivirine concentrations, which highlights the interest of using therapeutic drug monitoring in clinical practice. The population analysis performed with data from "real-life" conditions resulted in reliable post hoc estimates of pharmacokinetic parameters, suitable for individualization of dosing regimen.

Modeling intersubject variability of bronchial doses for inhaled radon progeny.

PubMed

Hofmann, Werner; Winkler-Heil, Renate; Hussain, Majid

2010-10-01

The main sources of intersubject variations considered in the present study were: (1) size and structure of nasal and oral passages, affecting extrathoracic deposition and, in further consequence, the fraction of the inhaled activity reaching the bronchial region; (2) size and asymmetric branching of the human bronchial airway system, leading to variations of diameters, lengths, branching angles, etc.; (3) respiratory parameters, such as tidal volume, and breathing frequency; (4) mucociliary clearance rates; and (5) thickness of the bronchial epithelium and depth of target cells, related to airway diameters. For the calculation of deposition fractions, retained surface activities, and bronchial doses, parameter values were randomly selected from their corresponding probability density functions, derived from experimental data, by applying Monte Carlo methods. Bronchial doses, expressed in mGy WLM-1, were computed for specific mining conditions, i.e., for defined size distributions, unattached fractions, and physical activities. Resulting bronchial dose distributions could be approximated by lognormal distributions. Geometric standard deviations illustrating intersubject variations ranged from about 2 in the trachea to about 7 in peripheral bronchiolar airways. The major sources of the intersubject variability of bronchial doses for inhaled radon progeny are the asymmetry and variability of the linear airway dimensions, the filtering efficiency of the nasal passages, and the thickness of the bronchial epithelium, while fluctuations of the respiratory parameters and mucociliary clearance rates seem to compensate each other.

Population pharmacokinetic (PK) analysis of laromustine, an emerging alkylating agent, in cancer patients.

PubMed

Nassar, Ala F; Wisnewski, Adam V; King, Ivan

2017-05-01

1. Alkylating agents are capable of introducing an alkyl group into nucleophilic sites on DNA or RNA through covalent bond. Laromustine is an active member of a relatively new class of sulfonylhydrazine prodrugs under development as antineoplastic alkylating agents, and displays significant single-agent activity. 2. This is the first report of the population pharmacokinetic analysis of laromustine, 106 patients, 66 with hematologic malignancies and 40 with solid tumors, participated in five clinical trials worldwide. Of these, 104 patients were included in the final NONMEM analysis. 3. The population estimates for total clearance (CL) and volume of distribution of the central compartment (V 1 ) were 96.3 L/h and 45.9 L, associated with high inter-patient variability of 52.9% and 79.8% and inter-occasion variability of 26.7% and 49.3%, respectively. The population estimates for Q and V 2 were 73.2 L/h and 29.9 L, and inter-patient variability in V 2 was 63.1%, respectively. 4. The estimate of V ss (75.8 L) exceeds total body water, indicating that laromustine is distributed to tissues. The half-life is short, less than 1 h, reflecting rapid clearance. Population PK analysis showed laromustine pharmacokinetics to be independent of dose and organ function with no effect on subsequent dosing cycles.

BK Polyomavirus-Specific 9mer CD8 T Cell Responses Correlate With Clearance of BK Viremia in Kidney Transplant Recipients: First Report From the Swiss Transplant Cohort Study.

PubMed

Leboeuf, C; Wilk, S; Achermann, R; Binet, I; Golshayan, D; Hadaya, K; Hirzel, C; Hoffmann, M; Huynh-Do, U; Koller, M T; Manuel, O; Mueller, N J; Mueller, T F; Schaub, S; van Delden, C; Weissbach, F H; Hirsch, H H

2017-10-01

BK polyomavirus (BKPyV) causes premature kidney transplant (KT) failure in 1-15% of patients. Because antivirals are lacking, most programs screen for BKPyV-viremia and, if positive, reduce immunosuppression. To evaluate the relationship of viremia and BKPyV-specific immunity, we examined prospectively cryopreserved plasma and peripheral blood mononuclear cells at the time of transplantation (T0) and at 6 mo (T6) and 12 mo (T12) after transplant from 28 viremic KT patients and 68 nonviremic controls matched for the transplantation period. BKPyV IgG seroprevalence was comparable between cases (89.3%) and controls (91.2%; p = 0.8635), but cases had lower antibody levels (p = 0.022) at T0. Antibody levels increased at T6 and T12 but were not correlated with viremia clearance. BKPyV-specific T cell responses to pools of overlapping 15mers (15mer peptide pool [15mP]) or immunodominant CD8 9mers (9mer peptide pool [9mP]) from the early viral gene region were not different between cases and controls at T0; however, clearance of viremia was associated with stronger 9mP responses at T6 (p = 0.042) and T12 (p = 0.048), whereas 15mP responses were not informative (T6 p = 0.359; T12 p = 0.856). BKPyV-specific T cells could be expanded in vitro from all patients after transplant, permitting identification of 78 immunodominant 9mer epitopes including 50 new ones across different HLA class I. Thus, 9mP-responses may be a novel marker of reconstituting CD8 T cell function that warrants further study as a complement of plasma BKPyV loads for guiding immunosuppression reduction. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

Inactivation of enveloped and non-enveloped viruses in the process of chemical treatment and gamma irradiation of bovine-derived grafting materials.

PubMed

Lee, Kwang-Il; Lee, Jung-Soo; Jung, Hong-Hee; Lee, Hwa-Yong; Moon, Seong-Hwan; Kang, Kyoung-Tak; Shim, Young-Bock; Jang, Ju-Woong

2012-01-01

Xenografts, unlike other grafting products, cannot be commercialized unless they conform to stringent safety regulations. Particularly with bovine-derived materials, it is essential to remove viruses and inactivate infectious factors because of the possibility that raw materials are imbrued with infectious viruses. The removal of the characteristics of infectious viruses from the bovine bone grafting materials need to be proved and inactivation process should satisfy the management provision of the Food and Drug Administration (FDA). To date, while most virus inactivation studies were performed in human allograft tissues, there have been almost no studies on bovine bone. To evaluate the efficacy of virus inactivation after treatment of bovine bone with 70% ethanol, 4% sodium hydroxide, and gamma irradiation, we selected a variety of experimental model viruses that are known to be associated with bone pathogenesis, including bovine parvovirus (BPV), bovine herpes virus (BHV), bovine viral diarrhea virus (BVDV), and bovine parainfluenza-3 virus (BPIV-3). The cumulative virus log clearance factor or cumulative virus log reduction factor for the manufacturing process was obtained by calculating the sum of the individual virus log clearance factors or log reduction factors determined for individual process steps with different physicochemical methods. The cumulative log clearance factors achieved by three different virus inactivation processes were as follows: BPV ≥ 17.73, BHV ≥ 20.53, BVDV ≥ 19.00, and BPIV-3 ≥ 16.27. On the other hand, the cumulative log reduction factors achieved were as follows: BPV ≥ 16.95, BHV ≥ 20.22, BVDV ≥ 19.27, and BPIV-3 ≥ 15.58. Treatment with 70% ethanol, 4% sodium hydroxide, or gamma irradiation was found to be very effective in virus inactivation, since all viruses were at undetectable levels during each process. We have no doubt that application of this established process to bovine bone graft manufacture will be effective and essential. © 2012 John Wiley & Sons A/S.

Messenger RNA-based therapeutics for brain diseases: An animal study for augmenting clearance of beta-amyloid by intracerebral administration of neprilysin mRNA loaded in polyplex nanomicelles.

PubMed

Lin, Chin-Yu; Perche, Federico; Ikegami, Masaru; Uchida, Satoshi; Kataoka, Kazunori; Itaka, Keiji

2016-08-10

Alzheimer's disease (AD) pathogenesis is considered to be the metabolic imbalance between anabolism and clearance of amyloid-beta (Aβ), and the strategy of breaking the equilibrium between soluble and insoluble forms of Aβ is likely to help prevent the progression of AD. Neprilysin (NEP) plays a major role in the clearance of Aβ in the brain, and its supplementation using viral vectors has shown to decrease Aβ deposition and prevent pathogenic changes in the brain. In this study, we developed a new therapeutic strategy by mRNA-based gene introduction. mRNA has the advantages of negligible risk of random integration into genome and not needing to be transcribed precludes the need for nuclear entry. This allows efficient protein expression in slowly-dividing or non-dividing cells, such as neural cells. We constructed mRNA encoding the mouse NEP protein and evaluated its ability degrade Aβ. In vitro transfection of NEP mRNA to primary neurons exhibited Amyloid Precursor Protein (APP) degradation activity superior to that of NEP encoding plasmid DNA. We then evaluated the in vivo activity of NEP mRNA by intracerebroventricular (i.c.v.) infusion using a cationic polymer-based PEGylated nanocarrier to form polyplex nanomicelles, which have been shown to have a high potential to deliver mRNA to various target tissues and organs. Nanomicelles carrying a GFP-NEP fusion mRNA produced efficient protein expression in a diffuse manner surrounding the ventricular space. An ELISA evaluation revealed that the mRNA infusion significantly augmented NEP level and effectively reduced the concentration of Aβ that had been supplemented in the mouse brain. To the best of our knowledge, this is the first study to demonstrate the therapeutic potential of introducing exogenous mRNA for the treatment of brain diseases, opening the new era of mRNA-based therapeutics. Copyright © 2016 Elsevier B.V. All rights reserved.

An Inducible Transgenic Mouse Model for Immune Mediated Hepatitis Showing Clearance of Antigen Expressing Hepatocytes by CD8+ T Cells

PubMed Central

Cebula, Marcin; Ochel, Aaron; Hillebrand, Upneet; Pils, Marina C.; Schirmbeck, Reinhold; Hauser, Hansjörg; Wirth, Dagmar

2013-01-01

The liver has the ability to prime immune responses against neo antigens provided upon infections. However, T cell immunity in liver is uniquely modulated by the complex tolerogenic property of this organ that has to also cope with foreign agents such as endotoxins or food antigens. In this respect, the nature of intrahepatic T cell responses remains to be fully characterized. To gain deeper insight into the mechanisms that regulate the CD8+ T cell responses in the liver, we established a novel OVA_X_CreERT2 mouse model. Upon tamoxifen administration OVA antigen expression is observed in a fraction of hepatocytes, resulting in a mosaic expression pattern. To elucidate the cross-talk of CD8+ T cells with antigen-expressing hepatocytes, we adoptively transferred Kb/OVA257-264-specific OT-I T cells to OVA_X_CreERT2 mice or generated triple transgenic OVA_X CreERT2_X_OT-I mice. OT-I T cells become activated in OVA_X_CreERT2 mice and induce an acute and transient hepatitis accompanied by liver damage. In OVA_X_CreERT2_X_OT-I mice, OVA induction triggers an OT-I T cell mediated, fulminant hepatitis resulting in 50% mortality. Surviving mice manifest a long lasting hepatitis, and recover after 9 weeks. In these experimental settings, recovery from hepatitis correlates with a complete loss of OVA expression indicating efficient clearance of the antigen-expressing hepatocytes. Moreover, a relapse of hepatitis can be induced upon re-induction of cured OVA_X_CreERT2_X_OT-I mice indicating absence of tolerogenic mechanisms. This pathogen-free, conditional mouse model has the advantage of tamoxifen inducible tissue specific antigen expression that reflects the heterogeneity of viral antigen expression and enables the study of intrahepatic immune responses to both de novo and persistent antigen. It allows following the course of intrahepatic immune responses: initiation, the acute phase and antigen clearance. PMID:23869228

Impact of global warming on viral diseases: what is the evidence?

PubMed

Zell, Roland; Krumbholz, Andi; Wutzler, Peter

2008-12-01

Global warming is believed to induce a gradual climate change. Hence, it was predicted that tropical insects might expand their habitats thereby transmitting pathogens to humans. Although this concept is a conclusive presumption, clear evidence is still lacking--at least for viral diseases. Epidemiological data indicate that seasonality of many diseases is further influenced by strong single weather events, interannual climate phenomena, and anthropogenic factors. So far, emergence of new diseases was unlinked to global warming. Re-emergence and dispersion of diseases was correlated with translocation of pathogen-infected vectors or hosts. Coupled ocean/atmosphere circulations and 'global change' that also includes shifting of demographic, social, and economical conditions are important drivers of viral disease variability whereas global warming at best contributes.

Repeat testing of low-level HIV-1 RNA: assay performance and implementation in clinical trials.

PubMed

White, Kirsten; Garner, Will; Wei, Lilian; Eron, Joseph J; Zhong, Lijie; Miller, Michael D; Martin, Hal; Plummer, Andrew; Tran-Muchowski, Cecilia; Lindstrom, Kim; Porter, James; Piontkowsky, David; Light, Angela; Reiske, Heinz; Quirk, Erin

2018-05-15

Assess the performance of HIV-1 RNA repeat testing of stored samples in cases of low-level viremia during clinical trials. Prospective and retrospective analysis of randomized clinical trial samples and reference standards. To evaluate assay variability of the Cobas AmpliPrep/Cobas TaqMan HIV-1 Test, v2.0, three separate sources of samples were utilized: the World Health Organization (WHO) HIV reference standard (assayed using 50 independent measurements at six viral loads <200 copies/ml), retrospective analysis of four to six aliquots of plasma samples from four clinical trial participants, and prospective repeat testing of 120 samples from participants in randomized trials with low-level viremia. The TaqMan assay on the WHO HIV-1 RNA standards at viral loads <200 copies/ml performed within the expected variability according to assay specifications. However, standards with low viral loads of 36 and 18 copies/ml reported values of ≥ 50 copies/ml in 66 and 18% of tests, respectively. In participants treated with antiretrovirals who had unexpected viremia of 50-200 copies/ml after achieving <50 copies/ml, retesting of multiple aliquots of stored plasma found <50 copies/ml in nearly all cases upon retesting (14/15; 93%). Repeat testing was prospectively implemented in four clinical trials for all samples with virologic rebound of 50-200 copies/ml (n = 120 samples from 92 participants) from which 42% (50/120) had a retest result of less than 50 copies/ml and 58% (70/120) retested ≥ 50 copies/ml. The TaqMan HIV-1 RNA assay shows variability around 50 copies/ml that affects clinical trial results and may impact clinical practice. In participants with a history of viral load suppression, unexpected low-level viremia may be because of assay variability rather than low drug adherence or true virologic failure. Retesting a stored aliquot of the same sample may differentiate between assay variability and virologic failure as the source of viremia. This retesting strategy could save time, money, and anxiety for patients and their providers, as well as decrease follow-up clinic visits without increasing the risk of virologic failure and resistance development.

Generation of a new cystatin C-based estimating equation for glomerular filtration rate by use of 7 assays standardized to the international calibrator.

PubMed

Grubb, Anders; Horio, Masaru; Hansson, Lars-Olof; Björk, Jonas; Nyman, Ulf; Flodin, Mats; Larsson, Anders; Bökenkamp, Arend; Yasuda, Yoshinari; Blufpand, Hester; Lindström, Veronica; Zegers, Ingrid; Althaus, Harald; Blirup-Jensen, Søren; Itoh, Yoshi; Sjöström, Per; Nordin, Gunnar; Christensson, Anders; Klima, Horst; Sunde, Kathrin; Hjort-Christensen, Per; Armbruster, David; Ferrero, Carlo

2014-07-01

Many different cystatin C-based equations exist for estimating glomerular filtration rate. Major reasons for this are the previous lack of an international cystatin C calibrator and the nonequivalence of results from different cystatin C assays. Use of the recently introduced certified reference material, ERM-DA471/IFCC, and further work to achieve high agreement and equivalence of 7 commercially available cystatin C assays allowed a substantial decrease of the CV of the assays, as defined by their performance in an external quality assessment for clinical laboratory investigations. By use of 2 of these assays and a population of 4690 subjects, with large subpopulations of children and Asian and Caucasian adults, with their GFR determined by either renal or plasma inulin clearance or plasma iohexol clearance, we attempted to produce a virtually assay-independent simple cystatin C-based equation for estimation of GFR. We developed a simple cystatin C-based equation for estimation of GFR comprising only 2 variables, cystatin C concentration and age. No terms for race and sex are required for optimal diagnostic performance. The equation, [Formula: see text] is also biologically oriented, with 1 term for the theoretical renal clearance of small molecules and 1 constant for extrarenal clearance of cystatin C. A virtually assay-independent simple cystatin C-based and biologically oriented equation for estimation of GFR, without terms for sex and race, was produced. © 2014 The American Association for Clinical Chemistry.

Mechanism-based pharmacokinetic modeling to evaluate transporter-enzyme interplay in drug interactions and pharmacogenetics of glyburide.

PubMed

Varma, Manthena V S; Scialis, Renato J; Lin, Jian; Bi, Yi-An; Rotter, Charles J; Goosen, Theunis C; Yang, Xin

2014-07-01

The purpose of this study is to characterize the involvement of hepato-biliary transport and cytochrome-P450 (CYP)-mediated metabolism in the disposition of glyburide and predict its pharmacokinetic variability due to drug interactions and genetic variations. Comprehensive in vitro studies suggested that glyburide is a highly permeable drug with substrate affinity to multiple efflux pumps and to organic anion transporting polypeptide (OATP)1B1 and OATP2B1. Active hepatic uptake was found to be significantly higher than the passive uptake clearance (15.8 versus 5.3 μL/min/10(6)-hepatocytes), using the sandwich-cultured hepatocyte model. In vitro, glyburide is metabolized (intrinsic clearance, 52.9 μL/min/mg-microsomal protein) by CYP3A4, CYP2C9, and CYP2C8 with fraction metabolism of 0.53, 0.36, and 0.11, respectively. Using these in vitro data, physiologically based pharmacokinetic models, assuming rapid-equilibrium between blood and liver compartments or permeability-limited hepatic disposition, were built to describe pharmacokinetics and evaluate drug interactions. Permeability-limited model successfully predicted glyburide interactions with rifampicin and other perpetrator drugs. Conversely, model assuming rapid-equilibrium mispredicted glyburide interactions, overall, suggesting hepatic uptake as the primary rate-determining process in the systemic clearance of glyburide. Further modeling and simulations indicated that the impairment of CYP2C9 function has a minimal effect on the systemic exposure, implying discrepancy in the contribution of CYP2C9 to glyburide clearance.

Diclofenac and metabolite pharmacokinetics in children.

PubMed

van der Marel, Caroline D; Anderson, Brian J; Rømsing, Janne; Jacqz-Aigrain, Evelyne; Tibboel, Dick

2004-06-01

Data concerning metabolism of diclofenac in children are limited to intravenous and enteric coated oral formulations. There are no data examining diclofenac or its hydroxyl metabolite pharmacokinetics after rectal administration in children. Infants (n = 26) undergoing tonsillectomy were given diclofenac 2 mg.kg(-1) followed by 1 mg.kg(-1) 8 h as suppository formulation for postoperative analgesia. Serum was assayed for diclofenac, 4'-hydroxydiclofenac and 5'-hydroxydiclofenac concentrations during the procedure and 1, 2 and 4 h postoperatively. The formation clearances of diclofenac to hydroxyl metabolites were estimated using nonlinear mixed effects models. A single compartment, first order absorption and first order elimination model was used to describe diclofenac pharmacokinetics. Published data from 11 children given enteric-coated diclofenac tablets were used to assess relative bioavailability. Mean (sd) age and weight of the patients were 4.5 (1.5) years and 20.5 (4.1) kg. The formation clearance to 4'-hydroxydiclofenac (% CV) and to 5'-hydroxydiclofenac were 8.41 (8.1) and 3.41 (113) l.h(-1) respectively, standardized to a 70 kg person using allometric '1/4 power' models. Clearance by other routes contributed 33.0 (64) l.h(-1) 70 kg(-1). Elimination clearance of hydroxyl metabolites was fixed at 27.5 l.h(-1) 70 kg(-1). The volumes of distribution of parent diclofenac and its hydroxyl metabolite were 22.8 (19.0) and 45.3 (l.70) kg(-1). The suppository formulation had an absorption half-life of 0.613 (33.2) h with a lag time of 0.188 (24.9) h. Interoccasion variability of formation clearance to 4'-hydroxydiclofenac, diclofenac volume of distribution, absorption half-time and lag time for the suppository was 36%, 55%, 14% and 119%, respectively. The relative bioavailability of the suppository compared with an enteric-coated tablet was 1.26. The formation clearance of the active metabolite 4'-hydroxydiclofenac contributed 19% of total clearance (44.82 l.h(-1) 70 kg(-1)). The rectum is a suitable route for administration of diclofenac in children 2-8 year of age and was associated with a higher relative bioavailabilty than enteric-coated tablets and an earlier maximum concentration (50 vs. 108 min). This pharmacokinetic profile renders diclofenac suppository a suitable formulation for short duration surgery.

Chronic viral hepatitis: the histology report.

PubMed

Guido, Maria; Mangia, Alessandra; Faa, Gavino

2011-03-01

In chronic viral hepatitis, the role of liver biopsy as a diagnostic test has seen a decline, paralleled by its increasing importance for prognostic purposes. Nowadays, the main indication for liver biopsy in chronic viral hepatitis is to assess the severity of the disease, in terms of both necro-inflammation (grade) and fibrosis (stage), which is important for prognosis and therapeutic management. Several scoring systems have been proposed for grading and staging chronic viral hepatitis and there is no a general consensus on the best system to be used in the daily practice. All scoring systems have their drawbacks and all may be affected by sampling and observer variability. Whatever the system used, a histological score is a reductive approach since damage in chronic viral hepatitis is a complex biological process. Thus, scoring systems are not intended to replace the detailed, descriptive, pathology report. In fact, lesions other than those scored for grading and staging may have clinical relevance and should be assessed and reported. This paper aims to provide a systematic approach to the interpretation of liver biopsies obtained in cases of chronic viral hepatitis, with the hope of helping general pathologists in their diagnostic practice. Copyright © 2011 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd.. All rights reserved.

Clinical prediction rule for differentiating tuberculous from viral meningitis.

PubMed

Hristea, A; Olaru, I D; Baicus, C; Moroti, R; Arama, V; Ion, M

2012-06-01

The Professor Dr Matei Bals National Institute of Infectious Diseases, Bucharest, Romania. To create a prediction rule to enable clinicians to differentiate patients with tuberculous meningitis (TBM) from those with viral meningitis. We retrospectively analysed patients admitted to a tertiary care facility between 2001 and 2011 with viral meningitis and TBM. Patients were defined as having TBM according to a recently published consensus definition, and as viral meningitis if a viral aetiology was confirmed, or after ruling out bacterial, fungal and non-infectious causes of meningitis. We identified 433 patients with viral meningitis and 101 TBM patients and compared their clinical and laboratory features. Multivariable analysis showed a statistically significant association between TBM and the following variables: duration of symptoms before admission of ≥5 days, presence of neurological impairment (altered consciousness, seizures, mild focal signs, multiple cranial nerve palsies, dense hemiplegia or paraparesis), cerebrospinal fluid/blood glucose ratio < 0.5 and cerebrospinal fluid protein level > 100 mg/dl. We propose a diagnostic score based on the coefficients derived from the logistic regression model with a sensitivity and specificity for TBM of respectively 92% and 94%. Our study suggests that easily available clinical and laboratory data are very useful for differentiating TBM from other causes of meningitis.

Evaluation of asbestos levels in two schools before and after asbestos removal. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karaffa, M.A.; Chesson, J.; Russell, J.

This report presents a statistical evaluation of airborne asbestos data collected at two schools before and after removal of asbestos-containing material (ACM). Although the monitoring data are not totally consistent with new Asbestos Hazard Emergency Response Act (AHERA) requirements and recent EPA guidelines, the study evaluates these historical data by standard statistical methods to determine if abated work areas meet proposed clearance criteria. The objectives of this statistical analysis were to compare (1) airborne asbestos levels indoors after removal with levels outdoors, (2) airborne asbestos levels before and after removal of asbestos, and (3) static sampling and aggressive sampling ofmore » airborne asbestos. The results of this evaluation indicated the following: the effect of asbestos removal on indoor air quality is unpredictable; the variability in fiber concentrations among different sampling sites within the same building indicates the need to treat different sites as separate areas for the purpose of clearance; and aggressive sampling is appropriate for clearance testing because it captures more entrainable asbestos structures. Aggressive sampling lowers the chance of declaring a worksite clean when entrainable asbestos is still present.« less

Detection of dehydration by using volume kinetics.

PubMed

Zdolsek, Joachim; Li, Yuhong; Hahn, Robert G

2012-10-01

Patients admitted to surgery may be dehydrated, which is difficult to diagnose except when it is severe (>5% Gl116 of the body weight). We hypothesized that modest dehydration can be detected by kinetic analysis of the blood hemoglobin concentration after a bolus infusion of crystalloid fluid. Four series of experiments were performed on 10 conscious, healthy male volunteers. Separated by at least 2 days, they received 5 or 10 mL/kg acetated Ringer's solution over 15 minutes. Before starting half of the IV infusions, volume depletion amounting to 1.5 to 2.0 L (approximately 2% of body weight) was induced with furosemide. The elimination clearance and the half-life of the infused fluid were calculated based on blood hemoglobin over 120 minutes. The perfusion index and the pleth variability index were monitored by pulse oximetry after a change of body position. Dehydration decreased the elimination clearance of acetated Ringer's solution [median (25th-75th percentile)] from 1.84 (1.23-2.57) to 0.53 (0.41-0.79) mL/kg/min (Wilcoxon matched-pair test P < 0.001) and increased the half-life from 23 (12-37) to 76 (57-101) minutes (P < 0.001). The smaller infusion, 5 mL/kg, fully discriminated between experiments performed in the euhydrated and dehydrated states, whereas the urinary excretion provided a less-reliable indication of hydration status. Dehydration decreased the perfusion index but did not affect the pleth variability index. Dehydration amounting to 2% of the body weight could be detected from the elimination clearance and the half-life of an infusion of 5 mL/kg Ringer's solution.

Population pharmacokinetics of pomalidomide in patients with relapsed or refractory multiple myeloma with various degrees of impaired renal function.

PubMed

Li, Yan; Wang, Xiaomin; O'Mara, Edward; Dimopoulos, Meletios A; Sonneveld, Pieter; Weisel, Katja C; Matous, Jeffrey; Siegel, David S; Shah, Jatin J; Kueenburg, Elisabeth; Sternas, Lars; Cavanaugh, Chloe; Zaki, Mohamed; Palmisano, Maria; Zhou, Simon

2017-01-01

Pomalidomide is an immunomodulatory drug for treatment of relapsed or refractory multiple myeloma (rrMM) in patients who often have comorbid renal conditions. To assess the impact of renal impairment on pomalidomide exposure, a population pharmacokinetics (PPK) model of pomalidomide in rrMM patients with various degrees of impaired renal function was developed. Intensive and sparse pomalidomide concentration data collected from two clinical studies in rrMM patients with normal renal function, moderately impaired renal function, severely impaired renal function not requiring dialysis, and with severely impaired renal function requiring dialysis were pooled over the dose range of 2 to 4 mg, to assess specifically the influence of the impaired renal function as a categorical variable and a continuous variable on pomalidomide clearance and plasma exposure. In addition, pomalidomide concentration data collected on dialysis days from both the withdrawal (arterial) side and from the returning (venous) side of the dialyzer, from rrMM patients with severely impaired renal function requiring dialysis, were used to assess the extent to which dialysis contributes to the removal of pomalidomide from blood circulation. PPK analyses demonstrated that moderate to severe renal impairment not requiring dialysis has no influence on pomalidomide clearance or plasma exposure, as compared to those patients with normal renal function, while pomalidomide exposure increased approximately 35% in patients with severe renal impairment requiring dialysis on nondialysis days. In addition, dialysis increased total body pomalidomide clearance from 5 L/h to 12 L/h, indicating that dialysis will significantly remove pomalidomide from the blood circulation. Thus, pomalidomide should be administered post-dialysis on the days of dialysis.

Prediction of Clinical Outcomes in Prenatal Hydronephrosis: Importance of Gravity Assisted Drainage.

PubMed

Sussman, Rachael D; Blum, Emily S; Sprague, Bruce M; Majd, Massoud; Rushton, H Gil; Pohl, Hans G

2017-03-01

In infants with SFU (Society for Fetal Urology) grade 3-4 congenital hydronephrosis, 99m Tc-mercaptoacetyltriglycine diuretic renography assesses differential function and drainage half-time. We routinely also include the percent of radiotracer drained after 30 minutes of diuresis as well as after 15 minutes with the patient in the upright position. We investigated whether any 1 or more of these parameters on initial diuretic renography predicts persistent or worsening drainage parameters. Infants 6 months or younger with grade 3-4 congenital hydronephrosis who presented between January 2009 and December 2014 were identified from billing data and included in analysis if they underwent at least 1 baseline diuretic renography. Those with structural anomalies were excluded from study. Baseline and followup differential function, diuresis half-time, clearance at 30 minutes and clearance with the patient upright were abstracted and comparisons were made between those with initially indeterminate diuresis half-time who underwent pyeloplasty vs those showing spontaneous improvement. A total of 74 patients (82 renal units) with presumed ureteropelvic junction obstruction met inclusion/exclusion criteria. All 10 renal units with initial diuresis half-time less than 5 minutes resolved spontaneously and all 25 renal units with initial diuresis half-time greater than 75 minutes underwent pyeloplasty. Therefore, we defined the indeterminate group as the 47 renal units with initial half-time between 5 and 75 minutes. Of those 47 renal units with indeterminate initial diuresis half-time 23 (47%) underwent pyeloplasty and 25 (53%) resolved spontaneously. Indications for pyeloplasty included worsening in 17 cases, persistent obstruction in 4 and urinary tract infection in 1. Among renal units with indeterminate drainage clearance while upright and clearance at 30 minutes were the only variables that differed significantly between surgical cases and those that resolved spontaneously. Radiotracer clearance with the patient upright and clearance at 30 minutes are more predictive of surgical management than diuresis half-time or differential function for renal units with indeterminate drainage. They should be included in the standard assessment of ureteropelvic junction obstruction. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Association of creatinine clearance with neutropenia in breast cancer patients undergoing chemotherapy with fluorouracil, doxorubicin, and cyclophosphamide (FAC).

PubMed

Montoya, J E; Luna, H G; Morelos, A B; Catedral, M M; Lava, A L; Amparo, J R; Cristal-Luna, G R

2013-04-01

Fluorouracil, doxorubicin, cyclophosphamide protocol (FAC) is a commonly used regimen for breast cancer due to its proven efficacy, acceptable toxicity, high affordability. While hepatic insufficiency dosing for doxorubicin and fluorouracil have been set, there is paucity of data in the literature on how to reduce doses in renal insufficiency. We sought to determine whether there is an association with pre-chemotherapy creatinine clearance, and the occurrence of clinically significant grade 3 to 5 neutropenia during the course of FAC chemotherapy. A retrospective study involving chart review from 2009 to June 2012, of breast cancer patients given FAC was conducted. Demographic profile, pre-chemotherapy complete blood count and creatinine clearance (CrCl) were recorded. Occurrence of Grade 3 to 5 neutropenia was the endpoint of the study. Descriptive statistics, one tailed t test, logistic regression analysis were done between the outcome and variables. A total of 53 patients were included in the study. The mean age of the patients was 49.77 ± 10.82 years. Patients had an ECOG performance status range of 1 to 3. Patients received mean 5.64 ± 0.92 cycles of FAC protocol chemotherapy. Pre-treatment chemotherapy WBC was 7.41 ± 2.68x109/L, Hemoglobin was 12.60 ± 1.16 g/dL, ANC 4656.89 ± 2379.32. Pre treatment CrCl was 90.79 ± 31.49 ml/min. Thirteen subjects, or 24.53% developed at least grade 3 neutropenia. Patients who developed neutropenia were significantly different from those who did not in terms of baseline WBC p=0.046 and Weight p=0.0119, CrCl p=0.032. Using logistic regression analysis, only creatinine clearance was a significant predictor of neutropenia. There was an inverse association between creatinine clearance and neutropenia, OR 0.887, 95% confidence interval (CI): 0.808- 0.973, p=0.011. The study revealed that breast cancer patients treated with FAC, there was an inverse association between creatinine clearance and occurrence of neutropenia.

Clinical associations of white matter damage in cART-treated HIV-positive children in South Africa.

PubMed

Hoare, Jacqueline; Fouche, Jean-Paul; Phillips, Nicole; Joska, John A; Donald, Kirsten A; Thomas, Kevin; Stein, Dan J

2015-04-01

A range of factors contributes to white matter damage in vertically infected HIV-positive children. These may include combination antiretroviral treatment (cART) regimen, sociodemographic factors, nutritional-hematological status, HIV-relevant clinical variables, and cognitive functioning. We explored associations between a number of these factors and diffusion tensor imaging (DTI) measures in 50 cART-treated children aged 6 to 15 years. Fractional anisotropy (FA), mean diffusion (MD), radial diffusion (RD), and axial diffusion (AD) were derived from 48 cerebral white matter regions. Significant associations between a number of the clinical variables and white matter integrity were found. Decreased FA, a measure of neuronal damage, was associated with being on second-line cART, low hemoglobin, and younger age. Children with increased MD, a measure of neuronal damage, were younger, had reduced albumin and hemoglobin, and increased viral load. Decreased AD, a measure of axonal damage, was associated with increased viral load and total protein, decreased albumin and hemoglobin, younger age, poorer fronto-striatal cognition, and being on second-line cART. Increased RD, a measure of myelin loss, was associated with younger age, low current CD4 count, low albumin and hemoglobin, and higher viral load and total protein. The current findings underline the possible association of first-line treatment failure with white matter brain dysfunction in pediatric neuroHIV and the importance of examining the effects of HIV disease in the context of treatable clinical variables such as anemia and nutritional status.

Rho'ing in and out of cells: viral interactions with Rho GTPase signaling.

PubMed

Van den Broeke, Céline; Jacob, Thary; Favoreel, Herman W

2014-01-01

Rho GTPases are key regulators of actin and microtubule dynamics and organization. Increasing evidence shows that many viruses have evolved diverse interactions with Rho GTPase signaling and manipulate them for their own benefit. In this review, we discuss how Rho GTPase signaling interferes with many steps in the viral replication cycle, especially entry, replication, and spread. Seen the diversity between viruses, it is not surprising that there is considerable variability in viral interactions with Rho GTPase signaling. However, several largely common effects on Rho GTPases and actin architecture and microtubule dynamics have been reported. For some of these processes, the molecular signaling and biological consequences are well documented while for others we just begin to understand them. A better knowledge and identification of common threads in the different viral interactions with Rho GTPase signaling and their ultimate consequences for virus and host may pave the way toward the development of new antiviral drugs that may target different viruses.

A Viral Receptor Complementation Strategy to Overcome CAV-2 Tropism for Efficient Retrograde Targeting of Neurons.

PubMed

Li, Shu-Jing; Vaughan, Alexander; Sturgill, James Fitzhugh; Kepecs, Adam

2018-06-06

Retrogradely transported neurotropic viruses enable genetic access to neurons based on their long-range projections and have become indispensable tools for linking neural connectivity with function. A major limitation of viral techniques is that they rely on cell-type-specific molecules for uptake and transport. Consequently, viruses fail to infect variable subsets of neurons depending on the complement of surface receptors expressed (viral tropism). We report a receptor complementation strategy to overcome this by potentiating neurons for the infection of the virus of interest-in this case, canine adenovirus type-2 (CAV-2). We designed AAV vectors for expressing the coxsackievirus and adenovirus receptor (CAR) throughout candidate projection neurons. CAR expression greatly increased retrograde-labeling rates, which we demonstrate for several long-range projections, including some resistant to other retrograde-labeling techniques. Our results demonstrate a receptor complementation strategy to abrogate endogenous viral tropism and thereby facilitate efficient retrograde targeting for functional analysis of neural circuits. Copyright © 2018 Elsevier Inc. All rights reserved.

Contact stresses in pin-loaded orthotropic plates

NASA Technical Reports Server (NTRS)

Hyer, M. W.; Klang, E. C.

1984-01-01

The effects of pin elasticity, friction, and clearance on the stresses near the hole in a pin-loaded orthotropic plate are described. The problem is modeled as a contact elasticity problem using complex variable theory, the pin and the plate being two elastic bodies interacting through contact. This modeling is in contrast to previous works which assumed that the pin is rigid or that it exerts a known cosinusoidal radial traction on the hole boundary. Neither of these approaches explicitly involves a pin. A collocation procedure and iteration were used to obtain numerical results for a variety of plate and pin elastic properties and various levels of friction and clearance. Collocation was used to enforce the boundary and iteration was used to find the contact and no-slip regions on the boundary. Details of the numerical scheme are discussed.

Complex antigen presentation pathway for an HLA-A*0201-restricted epitope from Chikungunya 6K protein

PubMed Central

Lemonnier, François A.; Esteban, Mariano

2017-01-01

Background The adaptive cytotoxic T lymphocyte (CTL)-mediated immune response is critical for clearance of many viral infections. These CTL recognize naturally processed short viral antigenic peptides bound to human leukocyte antigen (HLA) class I molecules on the surface of infected cells. This specific recognition allows the killing of virus-infected cells. The T cell immune T cell response to Chikungunya virus (CHIKV), a mosquito-borne Alphavirus of the Togaviridae family responsible for severe musculoskeletal disorders, has not been fully defined; nonetheless, the importance of HLA class I-restricted immune response in this virus has been hypothesized. Methodology/Principal findings By infection of HLA-A*0201-transgenic mice with a recombinant vaccinia virus that encodes the CHIKV structural polyprotein (rVACV-CHIKV), we identified the first human T cell epitopes from CHIKV. These three novel 6K transmembrane protein-derived epitopes are presented by the common HLA class I molecule, HLA-A*0201. One of these epitopes is processed and presented via a complex pathway that involves proteases from different subcellular locations. Specific chemical inhibitors blocked these events in rVACV-CHIKV-infected cells. Conclusions/Significance Our data have implications not only for the identification of novel Alphavirus and Togaviridae antiviral CTL responses, but also for analyzing presentation of antigen from viruses of different families and orders that use host proteinases to generate their mature envelope proteins. PMID:29084215

IL-17 suppresses immune effector functions in human papillomavirus-associated epithelial hyperplasia.

PubMed

Gosmann, Christina; Mattarollo, Stephen R; Bridge, Jennifer A; Frazer, Ian H; Blumenthal, Antje

2014-09-01

Persistent infection with high-risk human papillomaviruses (HPV) causes epithelial hyperplasia that can progress to cancer and is thought to depend on immunosuppressive mechanisms that prevent viral clearance by the host. IL-17 is a cytokine with diverse functions in host defense and in the pathology of autoimmune disorders, chronic inflammatory diseases, and cancer. We analyzed biopsies from patients with HPV-associated cervical intraepithelial neoplasia grade 2/3 and murine skin displaying HPV16 E7 protein-induced epithelial hyperplasia, which closely models hyperplasia in chronic HPV lesions. Expression of IL-17 and IL-23, a major inducer of IL-17, was elevated in both human HPV-infected and murine E7-expressing lesions. Using a skin-grafting model, we demonstrated that IL-17 in HPV16 E7 transgenic skin grafts inhibited effective host immune responses against the graft. IL-17 was produced by CD3(+) T cells, predominantly CD4(+) T cells in human, and CD4(+) and γδ T cells in mouse hyperplastic lesions. IL-23 and IL-1β, but not IL-18, induced IL-17 production in E7 transgenic skin. Together, these findings demonstrate an immunosuppressive role for IL-17 in HPV-associated epithelial hyperplasia and suggest that blocking IL-17 in persistent viral infection may promote antiviral immunity and prevent progression to cancer. Copyright © 2014 by The American Association of Immunologists, Inc.

Virus like particles as a platform for cancer vaccine development.

PubMed

Ong, Hui Kian; Tan, Wen Siang; Ho, Kok Lian

2017-01-01

Cancers have killed millions of people in human history and are still posing a serious health problem worldwide. Therefore, there is an urgent need for developing preventive and therapeutic cancer vaccines. Among various cancer vaccine development platforms, virus-like particles (VLPs) offer several advantages. VLPs are multimeric nanostructures with morphology resembling that of native viruses and are mainly composed of surface structural proteins of viruses but are devoid of viral genetic materials rendering them neither infective nor replicative. In addition, they can be engineered to display multiple, highly ordered heterologous epitopes or peptides in order to optimize the antigenicity and immunogenicity of the displayed entities. Like native viruses, specific epitopes displayed on VLPs can be taken up, processed, and presented by antigen-presenting cells to elicit potent specific humoral and cell-mediated immune responses. Several studies also indicated that VLPs could overcome the immunosuppressive state of the tumor microenvironment and break self-tolerance to elicit strong cytotoxic lymphocyte activity, which is crucial for both virus clearance and destruction of cancerous cells. Collectively, these unique characteristics of VLPs make them optimal cancer vaccine candidates. This review discusses current progress in the development of VLP-based cancer vaccines and some potential drawbacks of VLPs in cancer vaccine development. Extracellular vesicles with close resembling to viral particles are also discussed and compared with VLPs as a platform in cancer vaccine developments.

Complex antigen presentation pathway for an HLA-A*0201-restricted epitope from Chikungunya 6K protein.

PubMed

Lorente, Elena; Barriga, Alejandro; García-Arriaza, Juan; Lemonnier, François A; Esteban, Mariano; López, Daniel

2017-10-01

The adaptive cytotoxic T lymphocyte (CTL)-mediated immune response is critical for clearance of many viral infections. These CTL recognize naturally processed short viral antigenic peptides bound to human leukocyte antigen (HLA) class I molecules on the surface of infected cells. This specific recognition allows the killing of virus-infected cells. The T cell immune T cell response to Chikungunya virus (CHIKV), a mosquito-borne Alphavirus of the Togaviridae family responsible for severe musculoskeletal disorders, has not been fully defined; nonetheless, the importance of HLA class I-restricted immune response in this virus has been hypothesized. By infection of HLA-A*0201-transgenic mice with a recombinant vaccinia virus that encodes the CHIKV structural polyprotein (rVACV-CHIKV), we identified the first human T cell epitopes from CHIKV. These three novel 6K transmembrane protein-derived epitopes are presented by the common HLA class I molecule, HLA-A*0201. One of these epitopes is processed and presented via a complex pathway that involves proteases from different subcellular locations. Specific chemical inhibitors blocked these events in rVACV-CHIKV-infected cells. Our data have implications not only for the identification of novel Alphavirus and Togaviridae antiviral CTL responses, but also for analyzing presentation of antigen from viruses of different families and orders that use host proteinases to generate their mature envelope proteins.

New Insights Contributing to the Development of Effective Vaccines and Therapies to Reduce the Pathology Caused by hRSV.

PubMed

Gálvez, Nicolás M S; Soto, Jorge A; Kalergis, Alexis M

2017-08-11

Human Respiratory Syncytial Virus (hRSV) is one of the major causes of acute lower respiratory tract infections (ALRTI) worldwide, leading to significant levels of immunocompromisation as well as morbidity and mortality in infants. Its main target of infection is the ciliated epithelium of the lungs and the host immune responses elicited is ineffective at achieving viral clearance. It is thought that the lack of effective immunity against hRSV is due in part to the activity of several viral proteins that modulate the host immune response, enhancing a Th2-like pro-inflammatory state, with the secretion of cytokines that promote the infiltration of immune cells to the lungs, with consequent damage. Furthermore, the adaptive immunity triggered by hRSV infection is characterized by weak cytotoxic T cell responses and secretion of low affinity antibodies by B cells. These features of hRSV infection have meant that, to date, no effective and safe vaccines have been licensed. In this article, we will review in detail the information regarding hRSV characteristics, pathology, and host immune response, along with several prophylactic treatments and vaccine prototypes. We will also expose significant data regarding the newly developed BCG-based vaccine that promotes protective cellular and humoral response against hRSV infection, which is currently undergoing clinical evaluation.

Fatal acute hepatic failure in a family infected with the hepatitis A virus subgenotype IB

PubMed Central

Yoshida, Yuichi; Okada, Yohei; Suzuki, Akiko; Kakisaka, Keisuke; Miyamoto, Yasuhiro; Miyasaka, Akio; Takikawa, Yasuhiro; Nishizawa, Tsutomu; Okamoto, Hiroaki

2017-01-01

Abstract Rationale: Hepatitis A viral infection is a well-known cause of subclinical or acute self-limited hepatitis. Few cases of hepatitis A virus (HAV)–associated acute liver failure (ALF) have been reported in low HAV endemic countries annually. Patients concerns: To investigate the possible factors that affected the severity of HAV infection, a family cluster infected with the HAV subgenotype IB strain, which is not common in Japan, was described. Diagnoses: This family consisted of five members who all were infected with HAV. Interventions: Four of the five patients hospitalized except for an asymptomatic patient. Outcomes: Two of the five patients, men in their 50s and 60s, developed ALF, and one patient died. Various host factors, including sex (male), age, and a high bilirubin level, may affect the outcomes. Based on viral factors, HAV RNA was higher in the fatal case compared with others, and it decreased within a short period of time. The similarity of the nucleotide sequences was 99.9% among the HAV isolates based on an entire genomic sequence. Deletions and/or insertions on the HAV protein-coding sequences that caused a frameshift were found in surviving cases but not in the fatal case. Lessons: The rapid clearance of increased HAV and the absence of defective HAV might be closely associated with the onset of liver failure. PMID:28858094

Fatal acute hepatic failure in a family infected with the hepatitis A virus subgenotype IB: A case report.

PubMed

Yoshida, Yuichi; Okada, Yohei; Suzuki, Akiko; Kakisaka, Keisuke; Miyamoto, Yasuhiro; Miyasaka, Akio; Takikawa, Yasuhiro; Nishizawa, Tsutomu; Okamoto, Hiroaki

2017-09-01

Hepatitis A viral infection is a well-known cause of subclinical or acute self-limited hepatitis. Few cases of hepatitis A virus (HAV)-associated acute liver failure (ALF) have been reported in low HAV endemic countries annually. To investigate the possible factors that affected the severity of HAV infection, a family cluster infected with the HAV subgenotype IB strain, which is not common in Japan, was described. This family consisted of five members who all were infected with HAV. Four of the five patients hospitalized except for an asymptomatic patient. Two of the five patients, men in their 50s and 60s, developed ALF, and one patient died. Various host factors, including sex (male), age, and a high bilirubin level, may affect the outcomes. Based on viral factors, HAV RNA was higher in the fatal case compared with others, and it decreased within a short period of time. The similarity of the nucleotide sequences was 99.9% among the HAV isolates based on an entire genomic sequence. Deletions and/or insertions on the HAV protein-coding sequences that caused a frameshift were found in surviving cases but not in the fatal case. The rapid clearance of increased HAV and the absence of defective HAV might be closely associated with the onset of liver failure.

Microwave therapy for cutaneous human papilloma virus infection.

PubMed

Bristow, Ivan; Lim, Wen Chean; Lee, Alvin; Holbrook, Daniel; Savelyeva, Natalia; Thomson, Peter; Webb, Christopher; Polak, Marta; Ardern-Jones, Michael R

2017-10-01

Human papilloma virus (HPV) infects keratinocytes of the skin and mucous membranes, and is associated with the induction of cutaneous warts and malignancy. Warts can induce significant morbidity and disability but most therapies, including cryotherapy, laser, and radiofrequency devices show low efficacy and induce discomfort through tissue destruction. Microwaves are readily capable of passing through highly keratinised skin to deliver energy and induce heating of the tissue in a highly controllable, uniform manner. To determine the effects of microwave on cutaneous HPV infection. We undertook a pilot study of microwave therapy to the skin in 32 consecutive individuals with 52 recalcitrant long-lived viral cutaneous warts. Additionally, we undertook a molecular characterisation of the effects of microwaves on the skin. Tissue inflammation was minimal, but 75.9% of lesions cleared which compares favourably with previous studies showing a clearance rate of 23-33% for cryotherapy or salicylic acid. We show that microwaves specifically induce dendritic cell cross-presentation of HPV antigen to CD8+ T cells and suggest that IL-6 may be important for DC IRF1 and IRF4 modulation to enhance this process. Keratinocyte-skin dendritic cell cross-talk is integral to host defence against HPV infections, and this pilot study supports the concept of microwave induction of anti-HPV immunity which offers a promising approach for treatment of HPV-induced viral warts and potentially HPV-related cancers.

Ultrasensitive HCV RNA Quantification in Antiviral Triple Therapy: New Insight on Viral Clearance Dynamics and Treatment Outcome Predictors

PubMed Central

Garbuglia, Anna Rosa; Visco-Comandini, Ubaldo; Lionetti, Raffaella; Lapa, Daniele; Castiglione, Filippo; D’Offizi, Gianpiero; Taibi, Chiara; Montalbano, Marzia; Capobianchi, Maria Rosaria; Paci, Paola

2016-01-01

Objectives Identifying the predictive factors of Sustained Virological Response (SVR) represents an important challenge in new interferon-based DAA therapies. Here, we analyzed the kinetics of antiviral response associated with a triple drug regimen, and the association between negative residual viral load at different time points during treatment. Methods Twenty-three HCV genotype 1 (GT 1a n = 11; GT1b n = 12) infected patients were included in the study. Linear Discriminant Analysis (LDA) was used to establish possible association between HCV RNA values at days 1 and 4 from start of therapy and SVR. Principal component analysis (PCA) was applied to analyze the correlation between HCV RNA slope and SVR. A ultrasensitive (US) method was established to measure the residual HCV viral load in those samples which resulted “detected <12IU/ml” or undetectable with ABBOTT standard assay, and was retrospectively used on samples collected at different time points to establish its predictive power for SVR. Results According to LDA, there was no association between SVR and viral kinetics neither at time points earlier than 1 week (days 1 and 4) after therapy initiation nor later. The slopes were not relevant for classifying patients as SVR or no-SVR. No significant differences were observed in the median HCV RNA values at T0 among SVR and no-SVR patients. HCV RNA values with US protocol (LOD 1.2 IU/ml) after 1 month of therapy were considered; the area under the ROC curve was 0.70. Overall, PPV and NPV of undetectable HCV RNA with the US method for SVR was 100% and 46.7%, respectively; sensitivity and specificity were 38.4% and 100% respectively. Conclusion HCV RNA “not detected” by the US method after 1 month of treatment is predictive of SVR in first generation Protease inhibitor (PI)-based triple therapy. The US method could have clinical utility for advanced monitoring of virological response in new interferon based DAA combination regimens. PMID:27560794

Persistent infection with ebola virus under conditions of partial immunity.

PubMed

Gupta, Manisha; Mahanty, Siddhartha; Greer, Patricia; Towner, Jonathan S; Shieh, Wun-Ju; Zaki, Sherif R; Ahmed, Rafi; Rollin, Pierre E

2004-01-01

Ebola hemorrhagic fever in humans is associated with high mortality; however, some infected hosts clear the virus and recover. The mechanisms by which this occurs and the correlates of protective immunity are not well defined. Using a mouse model, we determined the role of the immune system in clearance of and protection against Ebola virus. All CD8 T-cell-deficient mice succumbed to subcutaneous infection and had high viral antigen titers in tissues, whereas mice deficient in B cells or CD4 T cells cleared infection and survived, suggesting that CD8 T cells, independent of CD4 T cells and antibodies, are critical to protection against subcutaneous Ebola virus infection. B-cell-deficient mice that survived the primary subcutaneous infection (vaccinated mice) transiently depleted or not depleted of CD4 T cells also survived lethal intraperitoneal rechallenge for >/==" BORDER="0">25 days. However, all vaccinated B-cell-deficient mice depleted of CD8 T cells had high viral antigen titers in tissues following intraperitoneal rechallenge and died within 6 days, suggesting that memory CD8 T cells by themselves can protect mice from early death. Surprisingly, vaccinated B-cell-deficient mice, after initially clearing the infection, were found to have viral antigens in tissues later (day 120 to 150 post-intraperitoneal infection). Furthermore, following intraperitoneal rechallenge, vaccinated B-cell-deficient mice that were transiently depleted of CD4 T cells had high levels of viral antigen in tissues earlier (days 50 to 70) than vaccinated undepleted mice. This demonstrates that under certain immunodeficiency conditions, Ebola virus can persist and that loss of primed CD4 T cells accelerates the course of persistent infections. These data show that CD8 T cells play an important role in protection against acute disease, while both CD4 T cells and antibodies are required for long-term protection, and they provide evidence of persistent infection by Ebola virus suggesting that under certain conditions of immunodeficiency a host can harbor virus for prolonged periods, potentially acting as a reservoir.

The impact of albendazole treatment on the incidence of viral- and bacterial-induced diarrhea in school children in southern Vietnam: study protocol for a randomized controlled trial.

PubMed

Leung, Jacqueline M; Hong, Chau Tran Thi; Trung, Nghia Ho Dang; Thi, Hoa Nhu; Minh, Chau Nguyen Ngoc; Thi, Thuy Vu; Hong, Dinh Thanh; Man, Dinh Nguyen Huy; Knowles, Sarah C L; Wolbers, Marcel; Hoang, Nhat Le Thanh; Thwaites, Guy; Graham, Andrea L; Baker, Stephen

2016-06-06

Anthelmintics are one of the more commonly available classes of drugs to treat infections by parasitic helminths (especially nematodes) in the human intestinal tract. As a result of their cost-effectiveness, mass school-based deworming programs are becoming routine practice in developing countries. However, experimental and clinical evidence suggests that anthelmintic treatments may increase susceptibility to other gastrointestinal infections caused by bacteria, viruses, or protozoa. Hypothesizing that anthelmintics may increase diarrheal infections in treated children, we aim to evaluate the impact of anthelmintics on the incidence of diarrheal disease caused by viral and bacterial pathogens in school children in southern Vietnam. This is a randomized, double-blinded, placebo-controlled trial to investigate the effects of albendazole treatment versus placebo on the incidence of viral- and bacterial-induced diarrhea in 350 helminth-infected and 350 helminth-uninfected Vietnamese school children aged 6-15 years. Four hundred milligrams of albendazole, or placebo treatment will be administered once every 3 months for 12 months. At the end of 12 months, all participants will receive albendazole treatment. The primary endpoint of this study is the incidence of diarrheal disease assessed by 12 months of weekly active and passive case surveillance. Secondary endpoints include the prevalence and intensities of helminth, viral, and bacterial infections, alterations in host immunity and the gut microbiota with helminth and pathogen clearance, changes in mean z scores of body weight indices over time, and the number and severity of adverse events. In order to reduce helminth burdens, anthelmintics are being routinely administered to children in developing countries. However, the effects of anthelmintic treatment on susceptibility to other diseases, including diarrheal pathogens, remain unknown. It is important to monitor for unintended consequences of drug treatments in co-infected populations. In this trial, we will examine how anthelmintic treatment impacts host susceptibility to diarrheal infections, with the aim of informing deworming programs of any indirect effects of mass anthelmintic administrations on co-infecting enteric pathogens. ClinicalTrials.gov: NCT02597556 . Registered on 3 November 2015.

Full-Length Characterization of Hepatitis C Virus Subtype 3a Reveals Novel Hypervariable Regions under Positive Selection during Acute Infection▿

PubMed Central

Humphreys, Isla; Fleming, Vicki; Fabris, Paolo; Parker, Joe; Schulenberg, Bodo; Brown, Anthony; Demetriou, Charis; Gaudieri, Silvana; Pfafferott, Katja; Lucas, Michaela; Collier, Jane; Huang, Kuan-Hsiang Gary; Pybus, Oliver G.; Klenerman, Paul; Barnes, Eleanor

2009-01-01

Hepatitis C virus subtype 3a is a highly prevalent and globally distributed strain that is often associated with infection via injection drug use. This subtype exhibits particular phenotypic characteristics. In spite of this, detailed genetic analysis of this subtype has rarely been performed. We performed full-length viral sequence analysis in 18 patients with chronic HCV subtype 3a infection and assessed genomic viral variability in comparison to other HCV subtypes. Two novel regions of intragenotypic hypervariability within the envelope protein E2, of HCV genotype 3a, were identified. We named these regions HVR495 and HVR575. They consisted of flanking conserved hydrophobic amino acids and central variable residues. A 5-amino-acid insertion found only in genotype 3a and a putative glycosylation site is contained within HVR575. Evolutionary analysis of E2 showed that positively selected sites within genotype 3a infection were largely restricted to HVR1, HVR495, and HVR575. Further analysis of clonal viral populations within single hosts showed that viral variation within HVR495 and HVR575 were subject to intrahost positive selecting forces. Longitudinal analysis of four patients with acute HCV subtype 3a infection sampled at multiple time points showed that positively selected mutations within HVR495 and HVR575 arose early during primary infection. HVR495 and HVR575 were not present in HCV subtypes 1a, 1b, 2a, or 6a. Some variability that was not subject to positive selection was present in subtype 4a HVR575. Further defining the functional significance of these regions may have important implications for genotype 3a E2 virus-receptor interactions and for vaccine studies that aim to induce cross-reactive anti-E2 antibodies. PMID:19740991

Precise determination of time to reach viral load set point after acute HIV-1 infection.

PubMed

Huang, Xiaojie; Chen, Hui; Li, Wei; Li, Haiying; Jin, Xia; Perelson, Alan S; Fox, Zoe; Zhang, Tong; Xu, Xiaoning; Wu, Hao

2012-12-01

The HIV viral load set point has long been used as a prognostic marker of disease progression and more recently as an end-point parameter in HIV vaccine clinical trials. The definition of set point, however, is variable. Moreover, the earliest time at which the set point is reached after the onset of infection has never been clearly defined. In this study, we obtained sequential plasma viral load data from 60 acutely HIV-infected Chinese patients among a cohort of men who have sex with men, mathematically determined viral load set point levels, and estimated time to attain set point after infection. We also compared the results derived from our models and that obtained from an empirical method. With novel uncomplicated mathematic model, we discovered that set points may vary from 21 to 119 days dependent on the patients' initial viral load trajectory. The viral load set points were 4.28 ± 0.86 and 4.25 ± 0.87 log10 copies per milliliter (P = 0.08), respectively, as determined by our model and an empirical method, suggesting an excellent agreement between the old and new methods. We provide a novel method to estimate viral load set point at the very early stage of HIV infection. Application of this model can accurately and reliably determine the set point, thus providing a new tool for physicians to better monitor early intervention strategies in acutely infected patients and scientists to rationally design preventative vaccine studies.

Virioplankton dynamics are related to eutrophication levels in a tropical urbanized bay

PubMed Central

Cabral, Anderson S.; Lessa, Mariana M.; Junger, Pedro C.; Thompson, Fabiano L.; Paranhos, Rodolfo

2017-01-01

Virioplankton are an important and abundant biological component of marine and freshwater ecosystems. Often overlooked, aquatic viruses play an important role in biogeochemical cycles on a global scale, infecting both autotrophic and heterotrophic microbes. Viral diversity, abundance, and viral interactions at different trophic levels in aqueous environments are not well understood. Tropical ecosystems are less frequently studied than temperate ecosystems, but could provide new insights into how physical and chemical variability can shape or force microbial community changes. In this study, we found high viral abundance values in Guanabara Bay relative to other estuaries around the world. Viral abundance was positively correlated with bacterioplankton abundance and chlorophyll a concentrations. Moreover, prokaryotic and viral abundance were positively correlated with eutrophication, especially in surface waters. These results provide novel baseline data on the quantitative distribution of aquatic viruses in tropical estuaries. They also provide new information on a complex and dynamic relationship in which environmental factors influence the abundance of bacterial hosts and consequently their viruses. Guanabara Bay is characterized by spatial and seasonal variations, and the eutrophication process is the most important factor explaining the structuring of virioplankton abundance and distribution in this tropical urbanized bay. PMID:28362842

Polymicrobial nature of vaginitis in young women: a microbiological and therapeutic study.

PubMed

Kippax, R A; Caradoc-Davies, G; Meech, R J

1982-03-24

Thirty-six young females attending the Student Health Service with vaginitis were investigated by serial semiquantitative aerobic, anaerobic, fungal, mycoplasma and viral cultures over a 10 day period and results were correlated with signs and symptoms. Antifungal therapy (econazole pessaries and cream) resulted in clearance of candida from 13 out of 16 patients where there was no increase in the anaerobic flora. In the four subjects where candida was isolated along with Gardnerella vaginalis plus abnormal anaerobic flora, only one cleared with econazole, the remaining three clearing during therapy with metronidazole. In the nine subjects with Gardnerella vaginalis and abnormal anaerobic flora, metronidazole relieved symptoms despite failure to eradicate G. vaginalis in seven indicating the pathogenic role of the anaerobic flora rather then G. vaginalis. Mycoplasma hominis, Ureaplasma urealyticum and gram negative enteric bacilli were not implicated as primary agents in causing vaginitis.

Modulating the function of the immune system by thyroid hormones and thyrotropin.

PubMed

Jara, Evelyn L; Muñoz-Durango, Natalia; Llanos, Carolina; Fardella, Carlos; González, Pablo A; Bueno, Susan M; Kalergis, Alexis M; Riedel, Claudia A

2017-04-01

Accumulating evidence suggests a close bidirectional communication and regulation between the neuroendocrine and immune systems. Thyroid hormones (THs) can exert responses in various immune cells, e.g., monocytes, macrophages, natural killer cells, and lymphocytes, affecting several inflammation-related processes (such as, chemotaxis, phagocytosis, reactive oxygen species generation, and cytokines production). The interactions between the endocrine and immune systems have been shown to contribute to pathophysiological conditions, including sepsis, inflammation, autoimmune diseases and viral infections. Under these conditions, TH therapy could contribute to restoring normal physiological functions. Here we discuss the effects of THs and thyroid stimulating hormone (TSH) on the immune system and the contribution to inflammation and pathogen clearance, as well as the consequences of thyroid pathologies over the function of the immune system. Copyright © 2017 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

The science of direct-acting antiviral and host-targeted agent therapy.

PubMed

Pawlotsky, Jean-Michel

2012-01-01

Direct-acting antiviral drugs targeting two major steps of the HCV life cycle, polyprotein processing and replication, and cyclophilin inhibitors, that target a host cell protein required to interact with the replication complex, have reached clinical development. In order to achieve a sustained virological response, that is, a cure of the HCV infection, it is necessary to shut down virus production, to maintain viral inhibition throughout treatment and to induce a significant, slower second-phase decline in HCV RNA levels that leads to definitive clearance of infected cells. Recent findings suggest that the interferon era is coming to an end in hepatitis C therapy and HCV infection can be cured by all-oral interferon-free treatment regimens within 12 to 24 weeks. Further results are awaited that will allow the establishment of an ideal first-line all-oral, interferon-free treatment regimen for patients with chronic HCV infection.

Integrins and small GTPases as modulators of phagocytosis.

PubMed

Sayedyahossein, Samar; Dagnino, Lina

2013-01-01

Phagocytosis is the mechanism whereby cells engulf large particles. This process has long been recognized as a critical component of the innate immune response, which constitutes the organism's defense against microorganisms. In addition, phagocytic internalization of apoptotic cells or cell fragments plays important roles in tissue homeostasis and remodeling. Phagocytosis requires target interactions with receptors on the plasma membrane of the phagocytic cell. Integrins have been identified as important mediators of particle clearance, in addition to their well-established roles in cell adhesion, migration and mechanotransduction. Indeed, these ubiquitously expressed proteins impart phagocytic capacity to epithelial, endothelial and mesenchymal cell types. The importance of integrins in particle internalization is emphasized by the ability of microbial and viral pathogens to exploit their signaling pathways to invade host cells, and by the wide variety of disorders that arise from abnormalities in integrin-dependent phagocytic uptake. Copyright © 2013 Elsevier Inc. All rights reserved.

Presence and Persistence of Zika Virus RNA in Semen, United Kingdom, 2016.

PubMed

Atkinson, Barry; Thorburn, Fiona; Petridou, Christina; Bailey, Daniel; Hewson, Roger; Simpson, Andrew J H; Brooks, Timothy J G; Aarons, Emma J

2017-04-01

Zika virus RNA has been detected in semen collected several months after onset of symptoms of infection. Given the potential for sexual transmission of Zika virus and for serious fetal abnormalities resulting from infection during pregnancy, information regarding the persistence of Zika virus in semen is critical for advancing our understanding of potential risks. We tested serial semen samples from symptomatic male patients in the United Kingdom who had a diagnosis of imported Zika virus infection. Among the initial semen samples from 23 patients, Zika virus RNA was detected at high levels in 13 (56.5%) and was not detected in 9 (39.1%); detection was indeterminate in 1 sample (4.4%). After symptomatic infection, a substantial proportion of men have detectable Zika virus RNA at high copy numbers in semen during early convalescence, suggesting high risk for sexual transmission. Viral RNA clearance times are not consistent and can be prolonged.

MicroRNA-155 Reinforces HIV Latency*

PubMed Central

Ruelas, Debbie S.; Chan, Jonathan K.; Oh, Eugene; Heidersbach, Amy J.; Hebbeler, Andrew M.; Chavez, Leonard; Verdin, Eric; Rape, Michael; Greene, Warner C.

2015-01-01

The presence of a small number of infected but transcriptionally dormant cells currently thwarts a cure for the more than 35 million individuals infected with HIV. Reactivation of these latently infected cells may result in three fates: 1) cell death due to a viral cytopathic effect, 2) cell death due to immune clearance, or 3) a retreat into latency. Uncovering the dynamics of HIV gene expression and silencing in the latent reservoir will be crucial for developing an HIV-1 cure. Here we identify and characterize an intracellular circuit involving TRIM32, an HIV activator, and miR-155, a microRNA that may promote a return to latency in these transiently activated reservoir cells. Notably, we demonstrate that TRIM32, an E3 ubiquitin ligase, promotes reactivation from latency by directly modifying IκBα, leading to a novel mechanism of NF-κB induction not involving IκB kinase activation. PMID:25873391

Molecular mechanisms and functions of pyroptosis, inflammatory caspases and inflammasomes in infectious diseases

PubMed Central

Man, Si Ming; Karki, Rajendra; Kanneganti, Thirumala-Devi

2017-01-01

SUMMARY Cell death is a fundamental biological phenomenon that is essential for the survival and development of an organism. Emerging evidence also indicate that cell death contributes to immune defense against infectious diseases. Pyroptosis is a form of inflammatory programed cell death pathway activated by human and mouse caspase-1, human caspase-4 and caspase-5, or mouse caspase-11. These inflammatory caspases are used by the host to control bacterial, viral, fungal or protozoan pathogens. Pyroptosis requires cleavage and activation of the pore-forming effector protein gasdermin D by inflammatory caspases. Physical rupture of the cell causes release of the pro-inflammatory cytokines IL-1β and IL-18, alarmins and endogenous danger-associated molecular patterns, signifying the inflammatory potential of pyroptosis. Here, we describe the central role of inflammatory caspases and pyroptosis in mediating immunity to infection and clearance of pathogens. PMID:28462526

Sinecatechins and imiquimod as proactive sequential therapy of external genital and perianal warts in adults.

PubMed

Schöfer, Helmut; Tatti, Silvio; Lynde, Charles W; Skerlev, Mihael; Hercogová, Jana; Rotaru, Maria; Ballesteros, Juan; Calzavara-Pinton, Piergiacomo

2017-12-01

This review about the proactive sequential therapy (PST) of external genital and perianal warts (EGW) is based on the most current available clinical literature and on the broad clinical experience of a group of international experts, physicians who are well versed in the treatment of human papillomavirus-associated diseases. It provides a practical guide for the treatment of EGW, including epidemiology, etiology, clinical appearance, and diagnostic procedures for these viral infections. Furthermore, the treatment goals and current treatment options, elucidating provider- and patient-applied therapies, and the parameters driving treatment decisions are summarized. Specifically, the mode of action of the topical treatments sinecatechins and imiquimod, as well as the PST for EGW to achieve rapid and sustained clearance is discussed. The group of experts has developed a treatment algorithm giving healthcare providers a practical tool for the treatment of EGW which is very valuable in the presence of many different treatment options.

Fcgamma receptor IIIA polymorphism as a risk factor for acute poliomyelitis.

PubMed

Rekand, Tiina; Langeland, Nina; Aarli, Johan A; Vedeler, Christian A

2002-12-15

Poliomyelitis is a viral infection that causes flaccid paralysis in approximately 1% of cases. The Fc receptors for immunoglobulin G (FcgammaR) are associated with modifying effects of several infectious and autoimmune diseases. To assess the influence of FcgammaR polymorphisms on the acute and late course of poliomyelitis, 110 Norwegian patients with well-defined histories of acute poliomyelitis were genotyped, of whom 50 suffered from the postpolio syndrome (PPS). In comparison with healthy control subjects without a history of poliomyelitis, significantly fewer patients had the FcgammaRIIIA genotype V/V (P<.01). However, this genotype was not an independent risk factor for PPS. The FcgammaRIIA and IIIB genotypes and allele frequencies did not differ between the patients and control subjects. The FcgammaRIIIA V/V genotype may lower the risk for contracting acute poliomyelitis through better clearance of poliovirus.

Glucocorticoid exposure alters the pathogenesis of Theiler’s murine encephalomyelitis virus during acute infection

PubMed Central

Young, Erin E.; Prentice, Thomas W.; Satterlee, Danielle; McCullough, Heath; Sieve, Amy N.; Johnson, Robin R.; Welsh, Thomas H.; Welsh, C. Jane R.; Meagher, Mary W.

2008-01-01

Previous research has shown that chronic restraint stress exacerbates Theiler’s virus infection, a murine model for CNS inflammation and multiple sclerosis. The current set of experiments was designed to evaluate the potential role of glucocorticoids in the deleterious effects of restraint stress on acute CNS inflammatory disease. Exposure to chronic restraint stress resulted in elevated levels of corticosterone as well as increased clinical scores and weight loss (Experiment 1). In addition, corticosterone administration alone exacerbated behavioral signs of TMEV-induced sickness (i.e. decreased body weight, increased symptoms of encephalitis, and increased mortality) and reduced inflammation in the CNS (Experiment 2). Infected subjects receiving exogenous corticosterone showed exacerbation of acute phase measures of sickness and severe mortality as well as decreased viral clearance from CNS (Experiment 3). These findings indicate that corticosterone exposure alone is sufficient to exacerbate acute CNS inflammatory disease. PMID:18538803

Numerical investigation of tip clearance cavitation in Kaplan runners

NASA Astrophysics Data System (ADS)

Nikiforova, K.; Semenov, G.; Kuznetsov, I.; Spiridonov, E.

2016-11-01

There is a gap between the Kaplan runner blade and the shroud that makes for a special kind of cavitation: cavitation in the tip leakage flow. Two types of cavitation caused by the presence of clearance gap are known: tip vortex cavitation that appears at the core of the rolled up vortex on the blade suction side and tip clearance cavitation that appears precisely in the gap between the blade tip edge and the shroud. In the context of this work numerical investigation of the model Kaplan runner has been performed taking into account variable tip clearance for several cavitation regimes. The focus is put on investigation of structure and origination of mechanism of cavitation in the tip leakage flow. Calculations have been performed with the help of 3-D unsteady numerical model for two-phase medium. Modeling of turbulent flow in this work has been carried out using full equations of Navier-Stokes averaged by Reynolds with correction for streamline curvature and system rotation. For description of this medium (liquid-vapor) simplification of Euler approach is used; it is based on the model of interpenetrating continuums, within the bounds of this two- phase medium considered as a quasi-homogeneous mixture with the common velocity field and continuous distribution of density for both phases. As a result, engineering techniques for calculation of cavitation conditioned by existence of tip clearance in model turbine runner have been developed. The detailed visualization of the flow was carried out and vortex structure on the suction side of the blade was reproduced. The range of frequency with maximum value of pulsation was assigned and maximum energy frequency was defined; it is based on spectral analysis of the obtained data. Comparison between numerical computation results and experimental data has been also performed. The location of cavitation zone has a good agreement with experiment for all analyzed regimes.

Population pharmacokinetic modelling of the changes in atazanavir plasma clearance caused by ritonavir plasma concentrations in HIV‐1 infected patients

PubMed Central

Moltó, José; Estévez, Javier A.; Miranda, Cristina; Cedeño, Samandhy; Clotet, Bonaventura

2016-01-01

Aims The aim of the present study was to develop a simultaneous population pharmacokinetic model for atazanavir (ATV) incorporating the effect of ritonavir (RTV) on clearance to predict ATV concentrations under different dosing regimens in HIV‐1‐infected patients. Methods A Cross‐sectional study was carried out in 83 HIV‐1‐infected adults taking ATV 400 mg or ATV 300 mg/RTV 100 mg once daily. Demographic and clinical characteristics were registered and blood samples collected to measure drug concentrations. A population pharmacokinetic model was constructed using nonlinear mixed‐effects modelling and used to simulate six dosing scenarios. Results The selected one‐compartmental model described the pharmacokinetics of RTV and ATV simultaneously, showing exponential, direct inhibition of ATV clearance according to the RTV plasma concentration, which explained 17.5% of the variability. A mean RTV plasma concentration of 0.63 mg l–1 predicted an 18% decrease in ATV clearance. The percentages of patients with an end‐of‐dose‐interval concentration of ATV below or above the minimum and maximum target concentrations of 0.15 mg l–1 and 0.85 mg l–1 favoured the selection of the simulated ATV/RTV once‐daily regimens (ATV 400 mg, ATV 300 mg/RTV 100 mg, ATV 300 mg/RTV 50 mg, ATV 200/RTV 100 mg) over the unboosted twice‐daily regimens (ATV 300 mg, ATV 200 mg). Conclusions A one‐compartment simultaneous model can describe the pharmacokinetics of RTV and ATV, including the effect of RTV plasma concentrations on ATV clearance. This model is promising for predicting individuals' ATV concentrations in clinical scenarios, and supports further clinical trials of once‐daily doses of ATV 300 mg/RTV 50 mg or ATV 200 mg/RTV 100 mg to confirm efficacy and safety. PMID:27447851

Population Pharmacokinetics of Combined Intravenous and Local Intrathecal Administration of Meropenem in Aneurysm Patients with Suspected Intracranial Infections After Craniotomy.

PubMed

Li, Xingang; Sun, Shusen; Wang, Qiang; Zhao, Zhigang

2018-02-01

For patients with intracranial infection, local intrathecal administration of meropenem may be a useful method to obtain a sufficient drug concentration in the cerebral spinal fluid (CSF). However, a large inter-individual variability may pose treatment efficacy at risk. This study aimed to identify factors affecting drug concentration in the CSF using population pharmacokinetics method. After craniotomy, aneurysm patients with an indwelling lumbar cistern drainage tube who received a combined intravenous and intrathecal administration of meropenem for the treatment of suspected intracranial infection were enrolled. Venous blood and CSF specimens were collected for determining meropenem concentrations. Nonlinear mixed-effects modeling method was used to fit blood and CSF concentrations simultaneously and to develop the population pharmacokinetic model. The proposed model was applied to simulate dosage regimens. A three-compartmental model was established to describe meropenem in vivo behavior. Lumbar CSF drainage resulted in a drug loss, and drug clearance in CSF (CL CSF ) was employed to describe this. The covariate analysis found that the drainage volume (mL/day) was strongly associated with CL CSF , and the effect of creatinine clearance was significant on the clearance of meropenem in blood (CL). Visual predictive check suggested that the proposed pharmacokinetic model agreed well with the observations. Simulation showed that both intravenous and intrathecal doses should be increased with the increases of minimum inhibitory concentration and daily CSF drainage volume. This model incorporates covariates of the creatinine clearance and the drainage volume, and a simple to use dosage regimen table was created to guide clinicians with meropenem dosing.

Pharmacokinetic Characteristics of Tofacitinib in Adult Patients With Moderate to Severe Chronic Plaque Psoriasis.

PubMed

Ma, Guangli; Xie, Rujia; Strober, Bruce; Langley, Richard; Ito, Kaori; Krishnaswami, Sriram; Wolk, Robert; Valdez, Hernan; Rottinghaus, Scott; Tallman, Anna; Gupta, Pankaj

2018-06-01

Tofacitinib is an oral Janus kinase (JAK) inhibitor. This study characterized the pharmacokinetics of tofacitinib in patients with psoriasis and evaluated the impact of patient factors on disposition. Pooled phase 2/3 data (2981 patients: 9735 concentrations, dose range: 2-15 mg twice daily) up to 56 weeks were used for modeling. A one-compartment model parameterized in terms of apparent oral clearance (CL/F), apparent volume of distribution, zero-order absorption (duration, D), with interindividual variability and inter-occasion variability terms, described tofacitinib pharmacokinetics. A full covariate model incorporated effects for age, sex, race, ethnicity, and baseline variables (body weight, Psoriasis Area Severity Index [PASI], C-reactive protein [CRP], creatinine clearance [CrCl]). The parameter estimates (95%CI) for CL/F, Vd/F, and D in a typical individual (white, male, 86 kg, 46 years, CrCl 121 mL/min, PASI 19.8, and CRP 0.267 mg/dL) were 26.7 (25.9, 27.5) L/h, 125 (120.8, 128.3) liters, and 0.69 (0.646, 0.735) hours, respectively. Only CrCl led to clinically relevant changes in exposure. The analysis suggested no dosing modifications for age, body weight, sex, race, ethnicity, baseline PASI, or CRP based on the magnitude of exposure change. Dosing adjustments for renal impairment were derived from a separate phase 1 study. © 2018, The American College of Clinical Pharmacology.

Novel Strategy to Evaluate Infectious Salmon Anemia Virus Variants by High Resolution Melting

PubMed Central

Sepúlveda, Dagoberto; Cárdenas, Constanza; Carmona, Marisela; Marshall, Sergio H.

2012-01-01

Genetic variability is a key problem in the prevention and therapy of RNA-based virus infections. Infectious Salmon Anemia virus (ISAv) is an RNA virus which aggressively attacks salmon producing farms worldwide and in particular in Chile. Just as with most of the Orthomyxovirus, ISAv displays high variability in its genome which is reflected by a wider infection potential, thus hampering management and prevention of the disease. Although a number of widely validated detection procedures exist, in this case there is a need of a more complex approach to the characterization of virus variability. We have adapted a procedure of High Resolution Melting (HRM) as a fine-tuning technique to fully differentiate viral variants detected in Chile and projected to other infective variants reported elsewhere. Out of the eight viral coding segments, the technique was adapted using natural Chilean variants for two of them, namely segments 5 and 6, recognized as virulence-associated factors. Our work demonstrates the versatility of the technique as well as its superior resolution capacity compared with standard techniques currently in use as key diagnostic tools. PMID:22719837

Single-Cell Analysis of the Impact of Host Cell Heterogeneity on Infection with Foot-and-Mouth Disease Virus.

PubMed

Xin, Xiu; Wang, Hailong; Han, Lingling; Wang, Mingzhen; Fang, Hui; Hao, Yao; Li, Jiadai; Zhang, Hu; Zheng, Congyi; Shen, Chao

2018-05-01

Viral infection and replication are affected by host cell heterogeneity, but the mechanisms underlying the effects remain unclear. Using single-cell analysis, we investigated the effects of host cell heterogeneity, including cell size, inclusion, and cell cycle, on foot-and-mouth disease virus (FMDV) infection (acute and persistent infections) and replication. We detected various viral genome replication levels in FMDV-infected cells. Large cells and cells with a high number of inclusions generated more viral RNA copies and viral protein and a higher proportion of infectious cells than other cells. Additionally, we found that the viral titer was 10- to 100-fold higher in cells in G 2 /M than those in other cell cycle phases and identified a strong correlation between cell size, inclusion, and cell cycle heterogeneity, which all affected the infection and replication of FMDV. Furthermore, we demonstrated that host cell heterogeneity influenced the adsorption of FMDV due to differences in the levels of FMDV integrin receptors expression. Collectively, these results further our understanding of the evolution of a virus in a single host cell. IMPORTANCE It is important to understand how host cell heterogeneity affects viral infection and replication. Using single-cell analysis, we found that viral genome replication levels exhibited dramatic variability in foot-and-mouth disease virus (FMDV)-infected cells. We also found a strong correlation between heterogeneity in cell size, inclusion number, and cell cycle status and that all of these characteristics affect the infection and replication of FMDV. Moreover, we found that host cell heterogeneity influenced the viral adsorption as differences in the levels of FMDV integrin receptors' expression. This study provided new ideas for the studies of correlation between FMDV infection mechanisms and host cells. Copyright © 2018 American Society for Microbiology.