Medium-chain fatty acid-sensing receptor, GPR84, is a proinflammatory receptor.

PubMed

Suzuki, Masakatsu; Takaishi, Sachiko; Nagasaki, Miyuki; Onozawa, Yoshiko; Iino, Ikue; Maeda, Hiroaki; Komai, Tomoaki; Oda, Tomiichiro

2013-04-12

G protein-coupled receptor 84 (GPR84) is a putative receptor for medium-chain fatty acids (MCFAs), whose pathophysiological roles have not yet been clarified. Here, we show that GPR84 was activated by MCFAs with the hydroxyl group at the 2- or 3-position more effectively than nonhydroxylated MCFAs. We also identified a surrogate agonist, 6-n-octylaminouracil (6-OAU), for GPR84. These potential ligands and the surrogate agonist, 6-OAU, stimulated [(35)S]GTP binding and accumulated phosphoinositides in a GPR84-dependent manner. The surrogate agonist, 6-OAU, internalized GPR84-EGFP from the cell surface. Both the potential ligands and 6-OAU elicited chemotaxis of human polymorphonuclear leukocytes (PMNs) and macrophages and amplified LPS-stimulated production of the proinflammatory cytokine IL-8 from PMNs and TNFα from macrophages. Furthermore, the intravenous injection of 6-OAU raised the blood CXCL1 level in rats, and the inoculation of 6-OAU into the rat air pouch accumulated PMNs and macrophages in the site. Our results indicate a proinflammatory role of GPR84, suggesting that the receptor may be a novel target to treat chronic low grade inflammation associated-disease.

Medium-chain Fatty Acid-sensing Receptor, GPR84, Is a Proinflammatory Receptor

PubMed Central

Suzuki, Masakatsu; Takaishi, Sachiko; Nagasaki, Miyuki; Onozawa, Yoshiko; Iino, Ikue; Maeda, Hiroaki; Komai, Tomoaki; Oda, Tomiichiro

2013-01-01

G protein-coupled receptor 84 (GPR84) is a putative receptor for medium-chain fatty acids (MCFAs), whose pathophysiological roles have not yet been clarified. Here, we show that GPR84 was activated by MCFAs with the hydroxyl group at the 2- or 3-position more effectively than nonhydroxylated MCFAs. We also identified a surrogate agonist, 6-n-octylaminouracil (6-OAU), for GPR84. These potential ligands and the surrogate agonist, 6-OAU, stimulated [35S]GTP binding and accumulated phosphoinositides in a GPR84-dependent manner. The surrogate agonist, 6-OAU, internalized GPR84-EGFP from the cell surface. Both the potential ligands and 6-OAU elicited chemotaxis of human polymorphonuclear leukocytes (PMNs) and macrophages and amplified LPS-stimulated production of the proinflammatory cytokine IL-8 from PMNs and TNFα from macrophages. Furthermore, the intravenous injection of 6-OAU raised the blood CXCL1 level in rats, and the inoculation of 6-OAU into the rat air pouch accumulated PMNs and macrophages in the site. Our results indicate a proinflammatory role of GPR84, suggesting that the receptor may be a novel target to treat chronic low grade inflammation associated-disease. PMID:23449982

Transport behavior of surrogate biological warfare agents in a simulated landfill: effect of leachate recirculation and water infiltration.

PubMed

Saikaly, Pascal E; Hicks, Kristin; Barlaz, Morton A; de Los Reyes, Francis L

2010-11-15

An understanding of the transport behavior of biological warfare (BW) agents in landfills is required to evaluate the suitability of landfills for the disposal of building decontamination residue (BDR) following a bioterrorist attack on a building. Surrogate BW agents, Bacillus atrophaeus spores and Serratia marcescens, were spiked into simulated landfill reactors that were filled with synthetic building debris (SBD) and operated for 4 months with leachate recirculation or water infiltration. Quantitative polymerase chain reaction (Q-PCR) was used to monitor surrogate transport. In the leachate recirculation reactors, <10% of spiked surrogates were eluted in leachate over 4 months. In contrast, 45% and 31% of spiked S. marcescens and B. atrophaeus spores were eluted in leachate in the water infiltration reactors. At the termination of the experiment, the number of retained cells and spores in SBD was measured over the depth of the reactor. Less than 3% of the total spiked S. marcescens cells and no B. atrophaeus spores were detected in SBD. These results suggest that significant fractions of the spiked surrogates were strongly attached to SBD.

Myosin light chains: Teaching old dogs new tricks

PubMed Central

Heissler, Sarah M; Sellers, James R

2014-01-01

The myosin holoenzyme is a multimeric protein complex consisting of heavy chains and light chains. Myosin light chains are calmodulin family members which are crucially involved in the mechanoenzymatic function of the myosin holoenzyme. This review examines the diversity of light chains within the myosin superfamily, discusses interactions between the light chain and the myosin heavy chain as well as regulatory and structural functions of the light chain as a subunit of the myosin holoenzyme. It covers aspects of the myosin light chain in the localization of the myosin holoenzyme, protein-protein interactions and light chain binding to non-myosin binding partners. Finally, this review challenges the dogma that myosin regulatory and essential light chain exclusively associate with conventional myosin heavy chains while unconventional myosin heavy chains usually associate with calmodulin. PMID:26155737

Revisiting photodynamic therapy dosimetry: reductionist & surrogate approaches to facilitate clinical success

NASA Astrophysics Data System (ADS)

Pogue, Brian W.; Elliott, Jonathan T.; Kanick, Stephen C.; Davis, Scott C.; Samkoe, Kimberley S.; Maytin, Edward V.; Pereira, Stephen P.; Hasan, Tayyaba

2016-04-01

Photodynamic therapy (PDT) can be a highly complex treatment, with many parameters influencing treatment efficacy. The extent to which dosimetry is used to monitor and standardize treatment delivery varies widely, ranging from measurement of a single surrogate marker to comprehensive approaches that aim to measure or estimate as many relevant parameters as possible. Today, most clinical PDT treatments are still administered with little more than application of a prescribed drug dose and timed light delivery, and thus the role of patient-specific dosimetry has not reached widespread clinical adoption. This disconnect is at least partly due to the inherent conflict between the need to measure and understand multiple parameters in vivo in order to optimize treatment, and the need for expedience in the clinic and in the regulatory and commercialization process. Thus, a methodical approach to selecting primary dosimetry metrics is required at each stage of translation of a treatment procedure, moving from complex measurements to understand PDT mechanisms in pre-clinical and early phase I trials, towards the identification and application of essential dose-limiting and/or surrogate measurements in phase II/III trials. If successful, identifying the essential and/or reliable surrogate dosimetry measurements should help facilitate increased adoption of clinical PDT. In this paper, examples of essential dosimetry points and surrogate dosimetry tools that may be implemented in phase II/III trials are discussed. For example, the treatment efficacy as limited by light penetration in interstitial PDT may be predicted by the amount of contrast uptake in CT, and so this could be utilized as a surrogate dosimetry measurement to prescribe light doses based upon pre-treatment contrast. Success of clinical ALA-based skin lesion treatment is predicted almost uniquely by the explicit or implicit measurements of photosensitizer and photobleaching, yet the individualization of treatment based upon each patients measured bleaching needs to be attempted. In the case of ALA, lack of PpIX is more likely an indicator that alternative PpIX production methods must be implemented. Parsimonious dosimetry, using surrogate measurements that are clinically acceptable, might strategically help to advance PDT in a medical world that is increasingly cost and time sensitive. Careful attention to methodologies that can identify and advance the most critical dosimetric measurements, either direct or surrogate, are needed to ensure successful incorporation of PDT into niche clinical procedures.

Sequence inversion and phenylalanine surrogates at the beta-turn enhance the antibiotic activity of gramicidin S.

PubMed

Solanas, Concepción; de la Torre, Beatriz G; Fernández-Reyes, María; Santiveri, Clara M; Jiménez, M Angeles; Rivas, Luis; Jiménez, Ana I; Andreu, David; Cativiela, Carlos

2010-05-27

A series of gramicidin S (GS) analogues have been synthesized where the Phe (i + 1) and Pro (i + 2) residues of the beta-turn have been swapped while the respective chiralities (D-, L-) at each position are preserved, and Phe is replaced by surrogates with aromatic side chains of diverse size, orientation, and flexibility. Although most analogues preserve the beta-sheet structure, as assessed by NMR, their antibiotic activities turn out to be highly dependent on the bulkiness and spatial arrangement of the aromatic side chain. Significant increases in microbicidal potency against both Gram-positive and Gram-negative pathogens are observed for several analogues, resulting in improved therapeutic profiles. Data indicate that seemingly minor replacements at the GS beta-turn can have significant impact on antibiotic activity, highlighting this region as a hot spot for modulating GS plasticity and activity.

Sequence inversion and phenylalanine surrogates at the β-turn enhance the antibiotic activity of gramicidin S

PubMed Central

Solanas, Concepción; de la Torre, Beatriz G.; Fernández-Reyes, María; Santiveri, Clara M.; Jiménez, M. Ángeles; Rivas, Luis; Jiménez, Ana I.; Andreu, David; Cativiela, Carlos

2010-01-01

A series of gramicidin S (GS) analogs have been synthesized where the Phe (i+1) and Pro (i+2) residues of the β-turn have been swapped while the respective chiralities (D-, L-) at each position are preserved, and Phe is replaced by surrogates with aromatic side chains of diverse size, orientation and flexibility. Although most analogs preserve the β-sheet structure, as assessed by NMR, their antibiotic activities turn out to be highly dependent on the bulkiness and spatial arrangement of the aromatic side chain. Significant increases in microbicidal potency against both Gram-positive and Gram-negative pathogens are observed for several analogs, resulting in improved therapeutic profiles. Data indicate that seemingly minor replacements at the GS β-turn can have significant impact on antibiotic activity, highlighting this region as a hot spot for modulating GS plasticity and activity. PMID:20411945

Association of plasma cell subsets in the bone marrow and free light chain concentrations in the serum of monoclonal gammopathy patients.

PubMed

Ayliffe, Michael John; Behrens, Judith; Stern, Simon; Sumar, Nazira

2012-08-01

This study investigated bone marrow plasma cell subsets and monoclonal free light chain concentrations in blood of monoclonal gammopathy patients. 54 bone marrow samples were stained by double immunofluorescence to enumerate cellular subsets making either intact monoclonal immunoglobulin or free light chains only. Blood taken at the same time was assayed for free light chains by an automated immunoassay. Patients were assigned to three cellular population categories: single intact monoclonal immunoglobulin (59%), dual monoclonal immunoglobulin and free light chain only (31%), or single free light chain only (9%). The median affected free light chain concentration of each group was 75 mg/l, 903 mg/l and 3320 mg/l, respectively, but with substantial overlap. In myeloma patients the difference in serum free light chain concentrations between patients with free light chain only marrow cells and those without was statistically significant. Serum free light chain levels >600 mg/l result mostly from marrow cells restricted to free light chain production.

Developing the role of the social worker as coordinator of services at the surrogate parenting center.

PubMed

Gagin, Roni; Cohen, Miri; Greenblatt, Lee; Solomon, Hanah; Itskovitz-Eldor, Joseph

2004-01-01

A law permitting couples to conceive biological children through surrogacy was legislated in Israel in March 1996. The Rambam Medical Center has established the only nonprofit Surrogate Parenting Center at a public hospital in Israel. The multidisciplinary teamwork at the Center is case managed by a social worker. An important role of the social work intervention is consultation and support for the couple and the surrogate at all stages of the process. The case study presented in the article illustrates the need for sensitive and professional intervention due to the complexity of the surrogacy process and the crisis it involves for both the surrogate and the couple. In light of the growing parenting surrogacy cases in the United States, Europe, and Israel, a structured social work intervention model is described, which may be implemented at public or private surrogate parenting centers.

Photosystem I from plants as a bacterial cytochrome P450 surrogate electron donor: terminal hydroxylation of branched hydrocarbon chains.

PubMed

Jensen, Kenneth; Johnston, Jonathan B; de Montellano, Paul R Ortiz; Møller, Birger Lindberg

2012-02-01

The ability of cytochrome P450 enzymes to catalyze highly regio- and stereospecific hydroxylations makes them attractive alternatives to approaches based on chemical synthesis but they require expensive cofactors, e.g. NAD(P)H, which limits their commercial potential. Ferredoxin (Fdx) is a multifunctional electron carrier that in plants accepts electrons from photosystem I (PSI) and facilitates photoreduction of NADP(+) to NADPH mediated by ferredoxin-NAD(P)H oxidoreductase (FdR). In bacteria, the electron flow is reversed and Fdx accepts electrons from NADPH via FdR and serves as the direct electron donor to bacterial P450s. By combining the two systems, we demonstrate that irradiation of PSI can drive the activity of a bacterial P450, CYP124 from Mycobacterium tuberculosis. The substitution of the costly cofactor NADPH with sunlight illustrates the potential of the light-driven hydroxylation system for biotechnology applications.

Serum Free Light Chains in Neoplastic Monoclonal Gammopathies: Relative Under-Detection of Lambda Dominant Kappa/Lambda Ratio, and Underproduction of Free Lambda Light Chains, as Compared to Kappa Light Chains, in Patients With Neoplastic Monoclonal Gammopathies.

PubMed

Lee, Won Sok; Singh, Gurmukh

2018-07-01

Quantitative evaluation of serum free light chains is recommended for the work up of monoclonal gammopathies. Immunoglobulin light chains are generally produced in excess of heavy chains. In patients with monoclonal gammopathy, κ/λ ratio is abnormal less frequently with lambda chain lesions. This study was undertaken to ascertain if the levels of overproduction of the two light chain types and their detection rates are different in patients with neoplastic monoclonal gammopathies. Results of serum protein electrophoresis (SPEP), serum protein immunofixation electrophoresis (SIFE), urine protein electrophoresis (UPEP), urine protein immunofixation electrophoresis (UIFE), and serum free light chain assay (SFLCA) in patients with monoclonal gammopathies were examined retrospectively. The κ/λ ratios were appropriately abnormal more often in kappa chain lesions. Ratios of κ/λ were normal in about 25% of patients with lambda chain lesions in whom free homogenous lambda light chains were detectable in urine. An illustrative case suggests underproduction of free lambda light chains, in some instances. The lower prevalence of lambda dominant κ/λ ratio in lesions with lambda light chains is estimated to be due to relative under-detection of lambda dominant κ/λ ratio in about 25% of the patients and because lambda chains are not produced in as much excess of heavy chains as are kappa chains, in about 5% of the patients. The results question the medical necessity and clinical usefulness of the serum free light chain assay. UPEP/UIFE is under-utilized.

Selecting Surrogates for an Alkylphenol Ethoxylate Analytical Method in Sewage and Soil Matrices

EPA Science Inventory

Alkylphenol ethoxylates (APEs) are nonionic surfactants commonly used in industrial detergents. These products contain complex mixtures of branched and linear chains. APEs and their degradation products, alkylphenols, are highly toxic to aquatic organisms, potentially estrogeni...

Serum Free Light Chains in Neoplastic Monoclonal Gammopathies: Relative Under-Detection of Lambda Dominant Kappa/Lambda Ratio, and Underproduction of Free Lambda Light Chains, as Compared to Kappa Light Chains, in Patients With Neoplastic Monoclonal Gammopathies

PubMed Central

Lee, Won Sok; Singh, Gurmukh

2018-01-01

Background Quantitative evaluation of serum free light chains is recommended for the work up of monoclonal gammopathies. Immunoglobulin light chains are generally produced in excess of heavy chains. In patients with monoclonal gammopathy, κ/λ ratio is abnormal less frequently with lambda chain lesions. This study was undertaken to ascertain if the levels of overproduction of the two light chain types and their detection rates are different in patients with neoplastic monoclonal gammopathies. Methods Results of serum protein electrophoresis (SPEP), serum protein immunofixation electrophoresis (SIFE), urine protein electrophoresis (UPEP), urine protein immunofixation electrophoresis (UIFE), and serum free light chain assay (SFLCA) in patients with monoclonal gammopathies were examined retrospectively. Results The κ/λ ratios were appropriately abnormal more often in kappa chain lesions. Ratios of κ/λ were normal in about 25% of patients with lambda chain lesions in whom free homogenous lambda light chains were detectable in urine. An illustrative case suggests underproduction of free lambda light chains, in some instances. Conclusions The lower prevalence of lambda dominant κ/λ ratio in lesions with lambda light chains is estimated to be due to relative under-detection of lambda dominant κ/λ ratio in about 25% of the patients and because lambda chains are not produced in as much excess of heavy chains as are kappa chains, in about 5% of the patients. The results question the medical necessity and clinical usefulness of the serum free light chain assay. UPEP/UIFE is under-utilized. PMID:29904440

Inhibition of enteric pathogens using integrated high intensity 405 nm LED on the surface of almonds

USDA-ARS?s Scientific Manuscript database

The disinfecting properties of 405 nm light were investigated against Escherichia coli O157:H7, Salmonella, and their non-pathogenic surrogates inoculated onto the surface of almonds. High intensity monochromatic light was generated from an array of narrow-band 405 nm light emitting diodes (LED). Al...

Comparison of lipases for in vitro models of gastric digestion: lipolysis using two infant formulas as model substrates.

PubMed

Sassene, P J; Fanø, M; Mu, H; Rades, T; Aquistapace, S; Schmitt, B; Cruz-Hernandez, C; Wooster, T J; Müllertz, A

2016-09-14

The aim of this study was to find a lipase suitable as a surrogate for Human Gastric Lipase (HGL), since the development of predictive gastrointestinal lipolysis models are hampered by the lack of a lipase with similar digestive properties as HGL. Three potential surrogates for HGL; Rhizopus Oryzae Lipase (ROL), Rabbit Gastric Lipase (RGL) and recombinant HGL (rHGL), were used to catalyze the in vitro digestion of two infant formulas (a medium-chain triacylglyceride enriched formula (MC-IF) and a predominantly long-chain triacylglyceride formula (LC-IF)). Digesta were withdrawn after 0, 5, 15, 30, 60 min of gastric digestion and after 90 or 180 min of intestinal digestion with or without the presence of pancreatic enzymes, respectively. The digesta were analyzed by scanning electron microscopy and gas chromatography to quantify the release of fatty acids (FAs). Digestions of both formulas, catalyzed by ROL, showed that the extent of gastric digestion was higher than expected from previously published in vivo data. ROL was furthermore insensitive to FA chain length and all FAs were released at the same pace. RGL and rHGL favoured the release of MC-FAs in both formulas, but rHGL did also release some LC-FAs during digestion of MC-IF, whereas RGL only released MC-FAs. Digestion of a MC-IF by HGL in vivo showed that MC-FAs are preferentially released, but some LC-FAs are also released. Thus of the tested lipase rHGL replicated the digestive properties of HGL the best and is a suitable surrogate for HGL for use in in vitro gastrointestinal lipolysis models.

An adaptive Gaussian process-based method for efficient Bayesian experimental design in groundwater contaminant source identification problems: ADAPTIVE GAUSSIAN PROCESS-BASED INVERSION

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

Zhang, Jiangjiang; Li, Weixuan; Zeng, Lingzao

Surrogate models are commonly used in Bayesian approaches such as Markov Chain Monte Carlo (MCMC) to avoid repetitive CPU-demanding model evaluations. However, the approximation error of a surrogate may lead to biased estimations of the posterior distribution. This bias can be corrected by constructing a very accurate surrogate or implementing MCMC in a two-stage manner. Since the two-stage MCMC requires extra original model evaluations, the computational cost is still high. If the information of measurement is incorporated, a locally accurate approximation of the original model can be adaptively constructed with low computational cost. Based on this idea, we propose amore » Gaussian process (GP) surrogate-based Bayesian experimental design and parameter estimation approach for groundwater contaminant source identification problems. A major advantage of the GP surrogate is that it provides a convenient estimation of the approximation error, which can be incorporated in the Bayesian formula to avoid over-confident estimation of the posterior distribution. The proposed approach is tested with a numerical case study. Without sacrificing the estimation accuracy, the new approach achieves about 200 times of speed-up compared to our previous work using two-stage MCMC.« less

λ Light Chain Bias Associated With Enhanced Binding and Function of Anti-HIV Env Glycoprotein Antibodies

PubMed Central

Sajadi, Mohammad M.; Farshidpour, Maham; Brown, Eric P.; Ouyang, Xin; Seaman, Michael S.; Pazgier, Marzena; Ackerman, Margaret E.; Robinson, Harriet; Tomaras, Georgia; Parsons, Matthew S.; Charurat, Manhattan; DeVico, Anthony L.; Redfield, Robert R.; Lewis, George K.

2016-01-01

The humoral response to human immunodeficiency virus (HIV) remains incompletely understood. In this report, we describe biased λ light chain use during the HIV Env glycoprotein (Env) response in HIV infection and vaccination. We examined HIV Env binding (and neutralization) in the context of light chain use in subjects with acute HIV infection, chronic HIV infection, and among HIV vaccinees. In all populations tested, there was a λ chain bias for HIV Env binding antibodies, compared with other HIV antigens (such as p24) or tetanus toxoid. In subjects with chronic HIV infection, a λ bias was noted for neutralization, with λ antibodies accounting for up to 90% of all neutralization activity observed. This is the first report of antibody function in a human infection being tied to light chain use. In HIV infection, antibodies expressing λ light chains tended to have longer CDRL3s, increased light chain contact with HIV Env, and less hypermutation in the heavy chain, compared with antibodies using the κ light chain. These data also support an evolutionary model for the understanding the various κ to λ light chain ratios observed across species and suggest that the λ light chain bias against HIV provides the host an advantage in developing a more efficient humoral response. PMID:26347575

Analysis of reduced monoclonal antibodies using size exclusion chromatography coupled with mass spectrometry

NASA Astrophysics Data System (ADS)

Liu, Hongcheng; Gaza-Bulseco, Georgeen; Chumsae, Chris

2009-12-01

Size-exclusion chromatography (SEC) has been widely used to detect antibody aggregates, monomer, and fragments. SEC coupled to mass spectrometry has been reported to measure the molecular weights of antibody; antibody conjugates, and antibody light chain and heavy chain. In this study, separation of antibody light chain and heavy chain by SEC and direct coupling to a mass spectrometer was further studied. It was determined that employing mobile phases containing acetonitrile, trifluoroacetic acid, and formic acid allowed the separation of antibody light chain and heavy chain after reduction by SEC. In addition, this mobile phase allowed the coupling of SEC to a mass spectrometer to obtain a direct molecular weight measurement. The application of the SEC-MS method was demonstrated by the separation of the light chain and the heavy chain of multiple recombinant monoclonal antibodies. In addition, separation of a thioether linked light chain and heavy chain from the free light chain and the free heavy chain of a recombinant monoclonal antibody after reduction was also achieved. This optimized method provided a separation of antibody light chain and heavy chain based on size and allowed a direct measurement of molecular weights by mass spectrometry. In addition, this method may help to identify peaks eluting from SEC column directly.

Evaluation of countermeasures for red light running by traffic simulator-based surrogate safety measures.

PubMed

Lee, Changju; So, Jaehyun Jason; Ma, Jiaqi

2018-01-02

The conflicts among motorists entering a signalized intersection with the red light indication have become a national safety issue. Because of its sensitivity, efforts have been made to investigate the possible causes and effectiveness of countermeasures using comparison sites and/or before-and-after studies. Nevertheless, these approaches are ineffective when comparison sites cannot be found, or crash data sets are not readily available or not reliable for statistical analysis. Considering the random nature of red light running (RLR) crashes, an inventive approach regardless of data availability is necessary to evaluate the effectiveness of each countermeasure face to face. The aims of this research are to (1) review erstwhile literature related to red light running and traffic safety models; (2) propose a practical methodology for evaluation of RLR countermeasures with a microscopic traffic simulation model and surrogate safety assessment model (SSAM); (3) apply the proposed methodology to actual signalized intersection in Virginia, with the most prevalent scenarios-increasing the yellow signal interval duration, installing an advance warning sign, and an RLR camera; and (4) analyze the relative effectiveness by RLR frequency and the number of conflicts (rear-end and crossing). All scenarios show a reduction in RLR frequency (-7.8, -45.5, and -52.4%, respectively), but only increasing the yellow signal interval duration results in a reduced total number of conflicts (-11.3%; a surrogate safety measure of possible RLR-related crashes). An RLR camera makes the greatest reduction (-60.9%) in crossing conflicts (a surrogate safety measure of possible angle crashes), whereas increasing the yellow signal interval duration results in only a 12.8% reduction of rear-end conflicts (a surrogate safety measure of possible rear-end crash). Although increasing the yellow signal interval duration is advantageous because this reduces the total conflicts (a possibility of total RLR-related crashes), each countermeasure shows different effects by RLR-related conflict types that can be referred to when making a decision. Given that each intersection has different RLR crash issues, evaluated countermeasures are directly applicable to enhance the cost and time effectiveness, according to the situation of the target intersection. In addition, the proposed methodology is replicable at any site that has a dearth of crash data and/or comparison sites in order to test any other countermeasures (both engineering and enforcement countermeasures) for RLR crashes.

Acquired Fanconi syndrome with proximal tubular cytoplasmic fibrillary inclusions of λ light chain restriction.

PubMed

Yao, Ying; Wang, Su-Xia; Zhang, You-Kang; Wang, Yan; Liu, Li; Liu, Gang

2014-01-01

Light chain proximal tubulopathy is a rarely reported entity associated with plasma cell dyscrasia that classically manifests as acquired Fanconi syndrome and is characterized by the presence of κ-restricted crystals in the proximal tubular cytoplasm. We herein present a case of multiple myeloma with Fanconi syndrome and acute kidney injury due to light chain proximal tubulopathy with light chain cast nephropathy. Prominent phagolysosomes and numerous irregularly shaped inclusions with a fibrillary matrix in the cytoplasm of the proximal tubules were identified on electron microscopy. A monotypic light chain of the λ type was detected in the distal tubular casts, proximal tubular cytoplasmic lysosomes and fibrillary inclusions on immunofluorescence and immune electron microscopy. This case underscores the importance of conducting careful ultrastructural investigations and immunocytologic examinations of light chains for detecting and diagnosing light chain proximal tubulopathy.

Proximal tubulopathies associated with monoclonal light chains: the spectrum of clinicopathologic manifestations and molecular pathogenesis.

PubMed

Herrera, Guillermo A

2014-10-01

Lesions associated with monoclonal light and heavy chains display a variety of glomerular, tubular interstitial, and vascular manifestations. While some of the entities are well recognized, including light and heavy chain deposition diseases, AL (light chain) and AH (heavy chain) amyloidosis, and light chain ("myeloma") cast nephropathy, other lesions centered on proximal tubules are much less accurately identified, properly diagnosed, and adequately understood in terms of pathogenesis and molecular mechanisms involved. These proximal tubule-centered lesions are typically associated with monoclonal light chains and have not been reported in patients with circulating monoclonal heavy chains. To determine the incidence of proximal tubulopathies in a series of patients with monoclonal light chain-related renal lesions and characterize them with an emphasis on clinical correlations and elucidation of molecular mechanisms involved in their pathogenesis. A study of 5410 renal biopsies with careful evaluation of light microscopic, immunofluorescence, and electron microscopic findings was conducted to identify these monoclonal light/heavy chain-related lesions. In selected cases, ultrastructural immunolabeling was performed to better illustrate and understand molecular mechanisms involved or to resolve specific diagnostic difficulties. In all, 2.5% of the biopsies were diagnosed as demonstrating renal pathology associated with monoclonal light or heavy chains. Of these, approximately 46% were classified as proximal tubule-centered lesions, also referred to as monoclonal light chain-associated proximal tubulopathies. These proximal tubulopathies were divided into 4 groups defined by characteristic immunomorphologic manifestations associated with specific clinical settings. These are important lesions whose recognition in the different clinical settings is extremely important for patients' clinical management, therapeutic purposes, and prognosis. These entities have been segregated into 4 distinct variants, conceptualized morphologically and clinically. Specific mechanisms involved in their pathogenesis are proposed.

Amino terminal sequence of heavy and light chains from ratfish immunoglobulin.

PubMed

De Ioannes, A E; Aguila, H L

1989-01-01

The ratfish, Callorhinchus callorhinchus, a representative of the Holocephali, has a natural serum hemagglutinin (Mr 960,000), composed of heavy (Mr 71,000), light (Mr 22,500), and J (Mr 16,000) chains. To approach the mechanisms that generate diversity at this level of evolution, the amino terminal sequence of the heavy and light chains was determined by automated microsequencing. The chains are unblocked and have modest internal sequence heterogeneity. The heavy chains show sequence similarity with the terminal region of the heavy chain from the horned shark, Heterodontus francisci, and other species. In contrast to the heavy chain, the ratfish light chains display low sequence similarity with their shark kappa counterparts. However, their similarity with the variable region of the chicken lambda light chains is about 75%.

Transparent, immiscible, surrogate liquids with matchable refractive indexes: Increased range of density and viscosity ratios

NASA Astrophysics Data System (ADS)

Cadillon, Jérémy; Saksena, Rajat; Pearlstein, Arne J.

2016-12-01

By replacing the "heavy" silicone oil used in the oil phase of Saksena, Christensen, and Pearlstein ["Surrogate immiscible liquid pairs with refractive indexes matchable over a wide range of density and viscosity ratios," Phys. Fluids 27, 087103 (2015)] by one with a twentyfold higher viscosity, and replacing the "light" silicone oil in that work by one with a viscosity fivefold lower and a density about 10% lower, we have greatly extended the range of viscosity ratio accessible by index-matching the adjustable-composition oil phase to an adjustable-composition 1,2-propanediol + CsBr + H2O aqueous phase and have also extended the range of accessible density ratios. The new system of index-matchable surrogate immiscible liquids is capable of achieving the density and viscosity ratios for liquid/liquid systems consisting of water with the entire range of light or medium crude oils over the temperature range from 40 °F (4.44 °C) to 200 °F (93.3 °C) and can access the density and viscosity ratios for water with some heavy crude oils over part of the same temperature range. It also provides a room-temperature, atmospheric-pressure surrogate for the liquid CO2 + H2O system at 0 °C over almost all of the pressure range of interest in sub-seabed CO2 sequestration.

Using the rate of bacterial clearance determined by real-time polymerase chain reaction as a timely surrogate marker to evaluate the appropriateness of antibiotic usage in critical patients with Acinetobacter baumannii bacteremia.

PubMed

Chuang, Yu-Chung; Chang, Shan-Chwen; Wang, Wei-Kung

2012-08-01

Bacteremia caused by Acinetobacter baumannii is becoming more frequent among critically ill patients, and has been associated with high mortality and prolonged hospital stay. Multidrug resistance and delay in blood culture have been shown to be significant barriers to appropriate antibiotic treatment. Quantitative polymerase chain reaction assays were recently used to monitor bacterial loads; we hypothesized that the rate of bacterial clearance determined by quantitative polymerase chain reaction can be used as a timely surrogate marker to evaluate the appropriateness of antibiotic usage. Prospective observational study. University hospital and research laboratory. Patients with culture-proven A. baumannii bacteremia in the intensive care units were prospectively enrolled from April 2008 to February 2009. Plasmid Oxa-51/pCRII-TOPO, which contained a 431-bp fragment of the A. baumannii-specific Oxa-51 gene in a pCRII-TOPO vector, was used as the standard. Sequential bacterial DNA loads in the blood were measured by a quantitative polymerase chain reaction assay. We enrolled 51 patients with A. baumannii bacteremia, and examined 318 sequential whole blood samples. The initial mean bacterial load was 2.15 log copies/mL, and the rate of bacterial clearance was 0.088 log copies/mL/day. Multivariate linear regression using the generalized estimation equation approach revealed that the use of immunosuppressants was an independent predictor for slower bacterial clearance (coefficient, 1.116; p<.001), and appropriate antibiotic usage was an independent predictor for more rapid bacterial clearance (coefficient, -0.995; p<.001). Patients with a slower rate of bacterial clearance experienced higher in-hospital mortality (odds ratio, 2.323; p=.04) Immunosuppression and appropriate antibiotic usage were independent factors affecting the rate of clearance of A. baumannii bacteremia in critical patients. These findings highlight the importance of appropriate antibiotic usage and development of effective antibiotics against A. baumannii in an era of emerging antibiotic resistance. The rate of bacterial clearance could serve as a timely surrogate marker for evaluating the appropriateness of antibiotics.

A binary plasmid system for shuffling combinatorial antibody libraries.

PubMed

Collet, T A; Roben, P; O'Kennedy, R; Barbas, C F; Burton, D R; Lerner, R A

1992-11-01

We have used a binary system of replicon-compatible plasmids to test the potential for promiscuous recombination of heavy and light chains within sets of human Fab fragments isolated from combinatorial antibody libraries. Antibody molecules showed a surprising amount of promiscuity in that a particular heavy chain could recombine with multiple light chains with retention of binding to a protein antigen. The degree to which a given heavy chain productively paired with any light chain to bind antigen varied from 43% to 100% and depended strongly on the heavy-chain sequence. Such productive crosses resulted in a set of Fab fragments of similar apparent binding constants, which seemed to differ mainly in the amount of active Fab fragment produced in the bacterial cell. The dominance of the heavy chain in the antibody-antigen interaction was further explored in a set of directed crosses, in which heavy and light chains derived from antigen-specific clones were crossed with nonrelated heavy and light chains. In these crosses, an Fab fragment retained antigen binding only if it contained a heavy chain from an antigen-specific clone. In no case did the light chain confer detectable affinity when paired with indifferent heavy chains. The surprising promiscuity of heavy chains has ramifications for the evaluation of the diversity of combinatorial libraries made against protein antigens and should allow the combination of one such promiscuous heavy chain with an engineered light chain to form an Fab fragment carrying synthetic cofactors to assist in antibody catalysis.

A binary plasmid system for shuffling combinatorial antibody libraries.

PubMed Central

Collet, T A; Roben, P; O'Kennedy, R; Barbas, C F; Burton, D R; Lerner, R A

1992-01-01

We have used a binary system of replicon-compatible plasmids to test the potential for promiscuous recombination of heavy and light chains within sets of human Fab fragments isolated from combinatorial antibody libraries. Antibody molecules showed a surprising amount of promiscuity in that a particular heavy chain could recombine with multiple light chains with retention of binding to a protein antigen. The degree to which a given heavy chain productively paired with any light chain to bind antigen varied from 43% to 100% and depended strongly on the heavy-chain sequence. Such productive crosses resulted in a set of Fab fragments of similar apparent binding constants, which seemed to differ mainly in the amount of active Fab fragment produced in the bacterial cell. The dominance of the heavy chain in the antibody-antigen interaction was further explored in a set of directed crosses, in which heavy and light chains derived from antigen-specific clones were crossed with nonrelated heavy and light chains. In these crosses, an Fab fragment retained antigen binding only if it contained a heavy chain from an antigen-specific clone. In no case did the light chain confer detectable affinity when paired with indifferent heavy chains. The surprising promiscuity of heavy chains has ramifications for the evaluation of the diversity of combinatorial libraries made against protein antigens and should allow the combination of one such promiscuous heavy chain with an engineered light chain to form an Fab fragment carrying synthetic cofactors to assist in antibody catalysis. Images PMID:1438192

Involvement of myosin light-chain kinase in endothelial cell retraction

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

Wysolmerski, R.B.; Lagunoff, D.

Permeabilized bovine pulmonary artery endothelial cell monolayers were used to investigate the mechanism of endothelial cell retraction. Postconfluent endothelial cells permeabilized with saponin retracted upon exposure to ATP and Ca{sup 2+}. Retraction was accompanied by thiophosphorylation of 19,000-Da myosin light chains when adenosine 5'-(gamma-({sup 35}S)thio)triphosphate was included in the medium. Both retraction and thiophosphorylation of myosin light chains exhibited a graded quantitative dependence on Ca{sup 2+}. When permeabilized monolayers were extracted in buffer D containing 100 mM KCl and 30 mM MgCl2 for 30 min, the cells failed to retract upon exposure to ATP and Ca{sup 2+}, and no thiophosphorylationmore » of myosin light chains occurred. The ability both to retract and to thiophosphorylate myosin light chains was restored by the addition to the permeabilized, extracted cells of myosin light-chain kinase and calmodulin together but not by either alone. These studies indicate that endothelial cell retraction, as does smooth muscle contraction, depends on myosin light-chain kinase phosphorylation of myosin light chains.« less

Site-directed mutagenesis of the regulatory light-chain Ca2+/Mg2+ binding site and its role in hybrid myosins

NASA Astrophysics Data System (ADS)

Reinach, Fernando C.; Nagai, Kiyoshi; Kendrick-Jones, John

1986-07-01

The regulatory light chains, small polypeptides located on the myosin head, regulate the interaction of myosin with actin in response to either Ca2+ or phosphorylation. The demonstration that the regulatory light chains on scallop myosin can be replaced by light chains from other myosins has allowed us to compare the functional capabilities of different light chains1, but has not enabled us to probe the role of features, such as the Ca2+/Mg2+ binding site, that are common to all of them. Here, we describe the use of site-directed mutagenesis to study the function of that site. We synthesized the chicken skeletal myosin light chain in Escherichia coli and constructed mutants with substitutions within the Ca2+/Mg2+ binding site. When the aspartate residues at the first and sixth Ca2+ coordination positions are replaced by uncharged alanines, the light chains have a reduced Ca2+ binding capacity but still bind to scallop myosin with high affinity. Unlike the wild-type skeletal light chain which inhibits myosin interaction with actin, the mutants activate it. Thus, an intact Ca2+/Mg2+ binding site in the N-terminal region of the light chain is essential for regulating the interaction of myosin with actin.

Huntingtin-interacting protein 1 (Hip1) and Hip1-related protein (Hip1R) bind the conserved sequence of clathrin light chains and thereby influence clathrin assembly in vitro and actin distribution in vivo.

PubMed

Chen, Chih-Ying; Brodsky, Frances M

2005-02-18

Clathrin heavy and light chains form triskelia, which assemble into polyhedral coats of membrane vesicles that mediate transport for endocytosis and organelle biogenesis. Light chain subunits regulate clathrin assembly in vitro by suppressing spontaneous self-assembly of the heavy chains. The residues that play this regulatory role are at the N terminus of a conserved 22-amino acid sequence that is shared by all vertebrate light chains. Here we show that these regulatory residues and others in the conserved sequence mediate light chain interaction with Hip1 and Hip1R. These related proteins were previously found to be enriched in clathrin-coated vesicles and to promote clathrin assembly in vitro. We demonstrate Hip1R binding preference for light chains associated with clathrin heavy chain and show that Hip1R stimulation of clathrin assembly in vitro is blocked by mutations in the conserved sequence of light chains that abolish interaction with Hip1 and Hip1R. In vivo overexpression of a fragment of clathrin light chain comprising the Hip1R-binding region affected cellular actin distribution. Together these results suggest that the roles of Hip1 and Hip1R in affecting clathrin assembly and actin distribution are mediated by their interaction with the conserved sequence of clathrin light chains.

Pretreatment to avoid positive RT-PCR results with inactivated viruses.

PubMed

Nuanualsuwan, Suphachai; Cliver, Dean O

2002-07-01

Enteric viruses that are important causes of human disease must often be detected by reverse transcription-polymerase chain reaction (RT-PCR), a method that commonly yields positive results with samples that contain only inactivated virus. This study was intended to develop a pretreatment for samples, so that inactivated viruses would not be detected by the RT-PCR procedure. Model viruses were human hepatitis A virus, vaccine poliovirus 1 and feline calicivirus as a surrogate for the Norwalk-like viruses. Each virus was inactivated (from an initial titer of approximately 10(3) PFU/ml) by ultraviolet light, hypochlorite or heating at 72 degrees C. Inactivated viruses, that were treated with proteinase K and ribonuclease for 30 min at 37 degrees C before RT-PCR, gave a negative result, which is to say that no amplicon was detected after the reaction was completed. This antecedent to the RT-PCR method may be applicable to other types of viruses, to viruses inactivated in other ways and to other molecular methods of virus detection.

Real-time characterization of partially observed epidemics using surrogate models.

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

Safta, Cosmin; Ray, Jaideep; Lefantzi, Sophia

We present a statistical method, predicated on the use of surrogate models, for the 'real-time' characterization of partially observed epidemics. Observations consist of counts of symptomatic patients, diagnosed with the disease, that may be available in the early epoch of an ongoing outbreak. Characterization, in this context, refers to estimation of epidemiological parameters that can be used to provide short-term forecasts of the ongoing epidemic, as well as to provide gross information on the dynamics of the etiologic agent in the affected population e.g., the time-dependent infection rate. The characterization problem is formulated as a Bayesian inverse problem, and epidemiologicalmore » parameters are estimated as distributions using a Markov chain Monte Carlo (MCMC) method, thus quantifying the uncertainty in the estimates. In some cases, the inverse problem can be computationally expensive, primarily due to the epidemic simulator used inside the inversion algorithm. We present a method, based on replacing the epidemiological model with computationally inexpensive surrogates, that can reduce the computational time to minutes, without a significant loss of accuracy. The surrogates are created by projecting the output of an epidemiological model on a set of polynomial chaos bases; thereafter, computations involving the surrogate model reduce to evaluations of a polynomial. We find that the epidemic characterizations obtained with the surrogate models is very close to that obtained with the original model. We also find that the number of projections required to construct a surrogate model is O(10)-O(10{sup 2}) less than the number of samples required by the MCMC to construct a stationary posterior distribution; thus, depending upon the epidemiological models in question, it may be possible to omit the offline creation and caching of surrogate models, prior to their use in an inverse problem. The technique is demonstrated on synthetic data as well as observations from the 1918 influenza pandemic collected at Camp Custer, Michigan.« less

Mediation of acetylcholine and substance P induced contractions by myosin light chain phosphorylation in feline colonic smooth muscle.

PubMed

Washabau, Robert J; Holt, David E; Brockman, Daniel J

2002-05-01

To determine the role of myosin light chain phosphorylation in feline colonic smooth muscle contraction. Colonic tissue was obtained from eight 12- to 24-month-old cats. Colonic longitudinal smooth muscle strips were attached to isometric force transducers for measurements of isometric stress. Myosin light chain phosphorylation was determined by isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Stress and phosphorylation were determined following stimulation with ACh or SP, in the absence or presence of a calmodulin antagonist (W-7; 0.1 to 1.0 mM), myosin light chain kinase inhibitor (ML-9; 1 to 10 microM), or extracellular calcium free solutions. Unstimulated longitudinal colonic smooth muscle contained low amounts (6.9+/-3.2%) of phosphorylated myosin light chain. Phosphorylation of the myosin light chains was dose and time dependent with maximal values of 58.5% at 30 seconds of stimulation with 100 microM Ach and 60.2% at 45 seconds of stimulation with 100 nM SP Active isometric stress development closely paralleled phosphorylation of the myosin light chains in ACh- or SP-stimulated muscle. W-7 and ML-9 dose dependently inhibited myosin light chain phosphorylation and isometric stress development associated with ACh or SP stimulation. Removal of extracellular calcium inhibited myosin light chain phosphorylation and isometric stress development in ACh-stimulated smooth muscle. Feline longitudinal colonic smooth muscle contraction is calcium-, calmodulin-, and myosin light chain kinase-dependent. Myosin light chain phosphorylation is necessary for the initiation of contraction in feline longitudinal colonic smooth muscle. These findings may prove useful in determining the biochemical and molecular defects that accompany feline colonic motility disorders.

Interpretation Difficulties of Serum Immunofixation Test in Immunoglobulin D Multiple Myeloma with Hidden Lambda Light Chains.

PubMed

Biaz, A; Uwingabiye, J; Rachid, A; Dami, A; Bouhsain, S; Ouzzif, Z; Idrissi, S El Machtani

2018-06-01

We report a case of immunoglobulin (Ig) D myeloma with hidden lambda light chains in a patient whose immunofixation test was very difficult to interpret: the IgD reacts with the anti-δ heavy chain antiserum but does not react with anti-lambda antiserum. The band in the D heavy chain lane is unmatched in light chain lanes and the band in lambda light chain lane migrates higher. To distinguish between heavy chain disease and immunoglobulin with "hidden" light chains, the sample was exposed to a very high concentration of anti-lambda and anti-kappa antisera for 48 hours. The serum immunofixation test of the sample treated with anti-lambda showed a decrease in the intensity of the band corresponding to D heavy chain lane as well as the modification of its mobility confirming the presence of IgD with the hidden lambda light chains. The IgD myeloma with hidden light chains remains a rare entity, hence the interest of sensitizing health professionals to be vigilant and ensure a good diagnosis. The proposed technique is useful, simple, reliable, and less laborious than those previous reported in the literature. Medical laboratories using Sebia-Hydrasys® system should be aware of the described phenomenon in order to avoid identifying an IgD myeloma as a delta heavy chain disease.

Surfactant-enhanced disinfection of the human norovirus surrogate, Tulane virus, with organic acids and surfactant

USDA-ARS?s Scientific Manuscript database

Combination treatments of surfactants and phenolic or short-chained organic acids (SCOA) may act synergistically or additively as sanitizers to inactive foodborne viruses and prevent outbreaks. The purpose of this study was to investigate the effect of gallic acid (GA), tannic acid (TA), p-coumaric ...

Characterization of myosin light chain in shrimp hemocytic phagocytosis.

PubMed

Han, Fang; Wang, Zhiyong; Wang, Xiaoqing

2010-11-01

Myosin light chain, a well-known cytoskeleton gene, regulates multiple processes that are involved in material transport, muscle shrink and cell division. However, its function in phagocytosis against invading pathogens in crustacean remains unknown. In this investigation, a myosin light chain gene was obtained from Marsupenaeus japonicus shrimp. The full-length cDNA of this gene was of 766 bp and an open reading frame (ORF) of 462 bp encoding a polypeptide of 153 amino acids. The myosin light chain protein was expressed in Escherichia coli and purified. Subsequently the specific antibody was raised using the purified GST fusion protein. As revealed by immuno-electron microscopy, the myosin light chain protein was only expressed in the dark bands of muscle. In the present study, the myosin light chain gene was up-regulated in the WSSV-resistant shrimp as revealed by real-time PCR and western blot. And the phagocytic percentage and phagocytic index using FITC-labeled Vibrio parahemolyticus were remarkably increased in the WSSV-resistant shrimp, suggesting that the myosin light chain protein was essential in hemocytic phagocytosis. On the other hand, RNAi assays indicated that the phagocytic percentage and phagocytic index were significantly decreased when the myosin light chain gene was silenced by sequence-specific siRNA. These findings suggested that myosin light chain protein was involved in the regulation of hemocytic phagocytosis of shrimp. Copyright 2010 Elsevier Ltd. All rights reserved.

Vasotropic light-chain amyloidosis and ischaemic cholangiopathy.

PubMed

Johnston, Emma L; Wilkinson, Mark; Knisely, A S

2015-06-25

A 75-year-old woman was incidentally found to have deranged liver function tests (LFTs). She was well, apart from 2 years of dyspnoea. Investigations had revealed atrial fibrillation and a right pleural effusion, without identified aetiology. On examination, the only finding was a palpable liver edge. Initial blood and ultrasound screening suggested no cause. The patient underwent liver biopsy. Microscopy showed κ-immunoglobulin light chains deposited exclusively in portal tracts, within blood vessel and bile duct walls. This pattern, although unusual, raised the possibility of κ-light chain disease. Serum electrophoresis was normal, as were serum immunoglobulin values. Serum concentrations of κ-light chains were elevated and microscopy of aspirated bone marrow found light-chain deposits with 10% plasmacytosis. Serum amyloid P (SAP) scintigraphy demonstrated splenic uptake. Myeloma, κ-light chain, with light-chain amyloidosis was diagnosed. The patient has responded well to cyclophosphamide, bortazomib and dexamethasone chemotherapy, and her LFTs are now nearly normal. 2015 BMJ Publishing Group Ltd.

Early Prognostic Value of Monitoring Serum Free Light Chain in Patients with Multiple Myeloma Undergoing Autologous Stem Cell Transplantation.

PubMed

Özkurt, Zübeyde Nur; Sucak, Gülsan Türköz; Akı, Şahika Zeynep; Yağcı, Münci; Haznedar, Rauf

2017-03-16

We hypothesized the levels of free light chains obtained before and after autologous stem cell transplantation can be useful in predicting transplantation outcome. We analyzed 70 multiple myeloma patients. Abnormal free light chain ratios before stem cell transplantation were found to be associated early progression, although without any impact on overall survival. At day +30, the normalization of levels of involved free light chain related with early progression. According to these results almost one-third reduction of free light chain levels can predict favorable prognosis after autologous stem cell transplantation.

Significant Differences in Physicochemical Properties of Human Immunoglobulin Kappa and Lambda CDR3 Regions.

PubMed

Townsend, Catherine L; Laffy, Julie M J; Wu, Yu-Chang Bryan; Silva O'Hare, Joselli; Martin, Victoria; Kipling, David; Fraternali, Franca; Dunn-Walters, Deborah K

2016-01-01

Antibody variable regions are composed of a heavy and a light chain, and in humans, there are two light chain isotypes: kappa and lambda. Despite their importance in receptor editing, the light chain is often overlooked in the antibody literature, with the focus being on the heavy chain complementarity-determining region (CDR)-H3 region. In this paper, we set out to investigate the physicochemical and structural differences between human kappa and lambda light chain CDR regions. We constructed a dataset containing over 29,000 light chain variable region sequences from IgM-transcribing, newly formed B cells isolated from human bone marrow and peripheral blood. We also used a published human naïve dataset to investigate the CDR-H3 properties of heavy chains paired with kappa and lambda light chains and probed the Protein Data Bank to investigate the structural differences between kappa and lambda antibody CDR regions. We found that kappa and lambda light chains have very different CDR physicochemical and structural properties, whereas the heavy chains with which they are paired do not differ significantly. We also observed that the mean CDR3 N nucleotide addition in the kappa, lambda, and heavy chain gene rearrangements are correlated within donors but can differ between donors. This indicates that terminal deoxynucleotidyl transferase may work with differing efficiencies between different people but the same efficiency in the different classes of immunoglobulin chain within one person. We have observed large differences in the physicochemical and structural properties of kappa and lambda light chain CDR regions. This may reflect different roles in the humoral immune response.

Significant Differences in Physicochemical Properties of Human Immunoglobulin Kappa and Lambda CDR3 Regions

PubMed Central

Townsend, Catherine L.; Laffy, Julie M. J.; Wu, Yu-Chang Bryan; Silva O’Hare, Joselli; Martin, Victoria; Kipling, David; Fraternali, Franca; Dunn-Walters, Deborah K.

2016-01-01

Antibody variable regions are composed of a heavy and a light chain, and in humans, there are two light chain isotypes: kappa and lambda. Despite their importance in receptor editing, the light chain is often overlooked in the antibody literature, with the focus being on the heavy chain complementarity-determining region (CDR)-H3 region. In this paper, we set out to investigate the physicochemical and structural differences between human kappa and lambda light chain CDR regions. We constructed a dataset containing over 29,000 light chain variable region sequences from IgM-transcribing, newly formed B cells isolated from human bone marrow and peripheral blood. We also used a published human naïve dataset to investigate the CDR-H3 properties of heavy chains paired with kappa and lambda light chains and probed the Protein Data Bank to investigate the structural differences between kappa and lambda antibody CDR regions. We found that kappa and lambda light chains have very different CDR physicochemical and structural properties, whereas the heavy chains with which they are paired do not differ significantly. We also observed that the mean CDR3 N nucleotide addition in the kappa, lambda, and heavy chain gene rearrangements are correlated within donors but can differ between donors. This indicates that terminal deoxynucleotidyl transferase may work with differing efficiencies between different people but the same efficiency in the different classes of immunoglobulin chain within one person. We have observed large differences in the physicochemical and structural properties of kappa and lambda light chain CDR regions. This may reflect different roles in the humoral immune response. PMID:27729912

Evaluation of 405nm CW visible blue light as a means of inactivating Tulane Virus on Blueberries

USDA-ARS?s Scientific Manuscript database

Introduction: Visible blue light (405nm) is effective against bacteria but its potential as a nonthermal intervention for viruses on foods, such as berries that are prone to norovirus contamination has not been evaluated. Tulane virus (TV) is now a common human norovirus surrogate that can be propa...

An investigation into UV light exposure as an experimental model for artificial aging on tensile strength and force delivery of elastomeric chain.

PubMed

Wahab, Siti Waznah; Bister, Dirk; Sherriff, Martyn

2014-02-01

This study investigated the effect of ultraviolet type A light (UVA) exposure on the tensile properties of elastomeric chain. UVA light exposure was used as model for artificial aging, simulating prolonged storage of elastomeric chain. Tensile strength (n = 60) was measured after exposing Ormco, Forestadent and 3M chains to UVA light for 0, 2, 3, and 4 weeks. Force decay was measured (n = 60) using chain exposed for 5, 10, and 14 days. The chains were subsequently stretched at a constant distance and the resulting forces measured at 0, 1, 24 hours and 7, 14, 21, and 28 days. This test simulated a clinical scenario of pre-stretching and subsequent shortening of elastomeric chain. Tensile strength had statistically significant difference and was directly related to the duration of ultraviolet (UV) light exposure. Forestadent chain, which had the second highest value for the 'as received' product, showed the most consistent values over time with the lowest degradation. Ormco showed the lowest values for 'as received' as well as after UV exposure; 3M chain had the highest loss of tensile strength. Force decay was also significantly different. UV light exposure of 10 days or more appears to mark a 'watershed' between products: 3M had most survivors, Forestadent chain had some survivors, depending on the time the chain was stretched for. None of the Ormco product survived UV light exposure for more than 5 days. UVA light exposure may be used as a model for artificial aging as it reduces force delivery and tensile strength of exposed chains.

Convergence analysis of surrogate-based methods for Bayesian inverse problems

NASA Astrophysics Data System (ADS)

Yan, Liang; Zhang, Yuan-Xiang

2017-12-01

The major challenges in the Bayesian inverse problems arise from the need for repeated evaluations of the forward model, as required by Markov chain Monte Carlo (MCMC) methods for posterior sampling. Many attempts at accelerating Bayesian inference have relied on surrogates for the forward model, typically constructed through repeated forward simulations that are performed in an offline phase. Although such approaches can be quite effective at reducing computation cost, there has been little analysis of the approximation on posterior inference. In this work, we prove error bounds on the Kullback-Leibler (KL) distance between the true posterior distribution and the approximation based on surrogate models. Our rigorous error analysis show that if the forward model approximation converges at certain rate in the prior-weighted L 2 norm, then the posterior distribution generated by the approximation converges to the true posterior at least two times faster in the KL sense. The error bound on the Hellinger distance is also provided. To provide concrete examples focusing on the use of the surrogate model based methods, we present an efficient technique for constructing stochastic surrogate models to accelerate the Bayesian inference approach. The Christoffel least squares algorithms, based on generalized polynomial chaos, are used to construct a polynomial approximation of the forward solution over the support of the prior distribution. The numerical strategy and the predicted convergence rates are then demonstrated on the nonlinear inverse problems, involving the inference of parameters appearing in partial differential equations.

Structure and energetic basis of overrepresented λ light chain in systemic light chain amyloidosis patients.

PubMed

Zhao, Jun; Zhang, Baohong; Zhu, Jianwei; Nussinov, Ruth; Ma, Buyong

2018-06-01

Amyloid formation and deposition of immunoglobulin light-chain proteins in systemic amyloidosis (AL) cause major organ failures. While the κ light-chain is dominant (λ/κ=1:2) in healthy individuals, λ is highly overrepresented (λ/κ=3:1) in AL patients. The structural basis of the amyloid formation and the sequence preference are unknown. We examined the correlation between sequence and structural stability of dimeric variable domains of immunoglobulin light chains using molecular dynamics simulations of 24 representative dimer interfaces, followed by energy evaluation of conformational ensembles for 20 AL patients' light chain sequences. We identified a stable interface with displaced N-terminal residues, provides the structural basis for AL protein fibrils formation. Proline isomerization may cause the N-terminus to adopt amyloid-prone conformations. We found that λ light-chains prefer misfolded dimer conformation, while κ chain structures are stabilized by a natively folded dimer. Our study may facilitate structure-based small molecule and antibody design to inhibit AL. This article is part of a Special Issue entitled: Accelerating Precision Medicine through Genetic and Genomic Big Data Analysis edited by Yudong Cai & Tao Huang. Copyright © 2017 Elsevier B.V. All rights reserved.

Surrogacy commissioning fathers and HIV.

PubMed

Jordaan, Donrich W

2013-10-11

Surrogacy is not regulated by a single legal instrument only, nor is confirmation of a surrogacy agreement by the High Court an unqualified green light for the surrogacy process to proceed. In the context of the HIV status of the commissioning father, whose gametes are to be used for the conception of the child in pursuance of a surrogacy agreement, the intended in vitro fertilisation of the surrogate mother may only take place on condition that the commissioning father, and his semen, have been tested for HIV; that he has consented to his HIV status being made available to the surrogate mother, and if he is HIV-positive, that sperm washing will be used to minimise the risk of infection and that the surrogate mother has been informed of his HIV status, and given her informed consent. 

Assessing the potential of surrogate EPS to mimic natural biofilm mechanical properties

NASA Astrophysics Data System (ADS)

Thom, Moritz; Schimmels, Stefan

2017-04-01

Biofilms growing on benthic sediments may increase the resistance towards erosion considerably by the sticky nature of extracellular polymeric substances (EPS). The EPS is a biopolymer which is secreted by the microorganisms inhabiting the biofilm matrix and may be regarded as natural glue. However, laboratory studies on the biostabilization effect mediated by biofilms are often hampered by the unavailability of "environmental" flumes in which light intensities, water temperature and nutrient content can be controlled. To allow investigations on biostabilization in "traditional" flume settings the use of surrogate materials is studied. Another advantage of using appropriate surrogates is the potential to reduce the experimental time, as compared to cultivating natural biofilms, the surrogates can readily be designed to mimic biofilms at different growth stages. Furthermore, the use of surrogates which are expected to have more homogeneous mechanical properties could facilitate fundamental studies to improve our knowledge on biostabilization. Even though a number of studies have already utilized EPS surrogates it is not clear how to mix them to correctly mimic natural EPS mechanical properties. In this study the adhesiveness (a measure of stickiness) on the surface of several EPS surrogates (e.g. Xanthan Gum, sodium alginate) is measured. These surrogates which are originally used in the food industry as rheology modifiers are mixed by adding water to a powder at a desired concentration (C). The measured surface adhesion of different surrogates at different concentrations ranged from 0.5 to 6.7 N/m2, which is well in line with values found for laboratory cultured biofilms. We found that the surrogate characteristics differed largely especially in regard to a) the response of the adhesiveness to increased concentrations (powder to water) and b) in their rheological characteristics. A seemingly promising surrogate for the use in biostabilization studies is Xanthan Gum (XG) which can be easily mixed to achieve natural-like adhesion values. A comparison of XG characteristics to natural biofilms cultivated under different environmental conditions and at different seasons will be provided at the conference along with more details on the different surrogates. These findings will help designing laboratory experiments on biofilm-stabilization by providing a first guideline for adequately mixing the surrogates to enable e.g. investigations on fundamental aspects of biostabilization or speeding up experiments with long cultivation times.

Observing Migration and Burial of Unexploded Ordnance in the Nearshore Environment with Instrumented Surrogates

NASA Astrophysics Data System (ADS)

Bruder, B. L.; Cristaudo, D.; Puleo, J. A.

2016-12-01

Prior to 1972, it was legal and common practice to unload unexploded ordnance (UXO) into the ocean. Only 60-100 miles off the US coast alone there are 72 dumping sites where it is estimated 31 million pounds of UXO lie. As recently as 2015, UXO have been found not only in the nearshore environment, but on populated beaches. Thus, understanding the migration and burial of these objects is not only of oceanographic interest, but a matter of public safety. The presented project evaluates the efficacy of instrumented UXO surrogates for observing munition migration and burial. Instrumented surrogates were exposed to near prototype scale wave conditions over a mobile bed at the Littoral Warfare Environment at Aberdeen Test Center, MD. Surrogates were deployed in the swash zone, inner and outer surf zones. Dependent on munition size, surrogates housed multiple suites of self-logging sensors. Sensor suites included different combinations of inertial motion units, ultra-wideband tracking tags, pressure transducers, shock recorders, and photocells. Preliminary results show sensor suites can resolve various types of surrogate movement. Pressure transducers accurately record ambient wave conditions as well as changes in mean depth due to surrogate migration. Inertial motion units resolve munition accelerations for rolling and translational motion. Inertial motion unit data is used to estimate trajectory as well when coupled with mean depth and bathymetric data. Photocells, which measure ambient light, resolve munition burial as well as serve as proxies for surrounding environmental conditions such as suspended sediment and water depth. The presented project will continue to utilize and couple surrogate sensor data to resolve munition movement and burial under different conditions. Knowledge of munition migration helps focus UXO detection and recovery, conserving US military and coastal resources.

The role of exoproteases in governing intraneuronal metabolism of botulinum toxin.

PubMed

Simpson, Lance L; Maksymowych, Andrew B; Kouguchi, Hirokazu; Dubois, Garrett; Bora, Roop S; Joshi, Suresh

2005-04-01

Botulinum toxin type A has a long duration of action, and thus it can block transmitter release for several weeks to several months. However, little is known about the precise mechanism that accounts for termination of toxin action. Therefore, experiments were done to gauge the effects of aminopeptidases and carboxypeptidases on the structure and function of the toxin. Exoproteases were added to the holotoxin, the native light chain, and a recombinant light chain. Treated toxin and light chain were examined for their effects on neuromuscular transmission and on isolated substrate. The data showed that aminopeptidase attack did not alter the N-terminus of the toxin/light chain, nor did it produce losses in biological activity. Carboxypeptidase attack did alter the C-terminus of the light chain, but not sufficiently to alter biological activity. The data suggest that the tertiary structure of the light chain confers upon the molecule substantial resistance to exoproteases.

Heavy and Light chain amyloidosois presenting as complete heart block: A rare presentation of a rare disease.

PubMed

Priyamvada, P S; Morkhandikar, S; Srinivas, B H; Parameswaran, S

2015-01-01

Amyloidosis is an uncommon disease characterized by deposition of proteinaceous material in the extracellular matrix, which results from abnormal protein folding. Even though more than 25 precursor proteins are identified, majority of systemic amyloidosis results from deposition of abnormal immunoglobulin (Ig) light chains. In heavy chain amyloidosis (AH), deposits are derived from both heavy chain alone, whereas in heavy and light chain amyloidosis (AHL), the deposits are derived from Ig heavy chains and light chains. Both AH and AHL are extremely rare diseases. Here, we report an unusual presentation of IgG (lambda) AHL amyloidosis in the background of multiple myeloma, where the initial clinical presentation was complete heart block, which preceded the definitive diagnosis by 18 months.

Clinicopathologic characteristics of light chain proximal tubulopathy with light chain inclusions involving multiple renal cell types
.

PubMed

Li, Xiaomei; Xu, Feng; Liang, Dandan; Liang, Shaoshan; Zhu, Xiaodong; Zhang, Mingchao; Huang, Xianghua; Liu, Zhihong; Zeng, Caihong

2018-02-01

Light chain proximal tubulopathy (LCPT) associated with plasma cell dyscrasias is a rare abnormality, especially cases involving multiple cell types. The aim of this study is to explore the characteristics and outcomes of these diseases. We comprehensively evaluated the clinical-pathological data, treatment, and outcomes of 6 LCPT patients with involvement of multiple cell types. In 3 cases, we found that the inclusions largely existed in tubular cells, while in 2 cases they coexisted in podocytes and tubular cells, and in 1 case they coexisted in histiocytes and tubular cells. The stain features and appearances of inclusions were specific and varied. Five patients displayed κ-light chains with crystal formation, while 1 patient displayed a λ subtype with increased lysosomes instead of crystals. Six patients presented with proteinuria, 4 with renal insufficiency, and 4 with complete or partial Fanconi syndrome. Our findings indicate that tubular cells are the most common location of cytoplasmic inclusions. Cases with κ-light chain storage are more common than λ, and the formation of crystals may be associated with the subtype of light chains. Immunoelectron microscopy could be used to increase sensitivity for the detection and location of monoclonal light chains. Therefore, these patients have some common clinical features with varied pathologic characteristics and prognoses but the same subtype of light chains.
.

Convergent mechanisms favor fast amyloid formation in two lambda 6a Ig light chain mutants.

PubMed

Valdés-García, Gilberto; Millán-Pacheco, César; Pastor, Nina

2017-08-01

Extracellular deposition as amyloids of immunoglobulin light chains causes light chain amyloidosis. Among the light chain families, lambda 6a is one of the most frequent in light chain amyloidosis patients. Its germline protein, 6aJL2, and point mutants, R24G and P7S, are good models to study fibrillogenesis, because their stability and fibril formation characteristics have been described. Both mutations make the germline protein unstable and speed up its ability to aggregate. To date, there is no molecular mechanism that explains how these differences in amyloidogenesis can arise from a single mutation. To look into the structural and dynamical differences in the native state of these proteins, we carried out molecular dynamics simulations at room temperature. Despite the structural similarity of the germline protein and the mutants, we found differences in their dynamical signatures that explain the mutants' increased tendency to form amyloids. The contact network alterations caused by the mutations, though different, converge in affecting two anti-aggregation motifs present in light chain variable domains, suggesting a different starting point for aggregation in lambda chains compared to kappa chains. © 2017 Wiley Periodicals, Inc.

Uses of monoclonial antibody 8H9

DOEpatents

Cheung, Nai-Kong V.

2015-06-23

This invention provides an antibody that binds the same antigen as that of monoclonal antibody 8H9, wherein the heavy chain CDR (Complementary Determining Region)1 comprises NYDIN, heavy chain CDR2 comprises WIFPGDGSTQY, heavy chain CDR3 comprises QTTATWFAY, and the light chain CDR1 comprises RASQSISDYLH, light chain CDR2 comprises YASQSIS, and light chain CDR3 comprises QNGHSFPLT. In another embodiment, there is provided a polypeptide that binds the same antigen as that of monoclonal antibody 8H9, wherein the polypeptide comprises NYDIN, WIFPGDGSTQY, QTTATWFAY, RASQSISDYLH, YASQSIS, and QNGHSFPLT.

Comparison of Free Light Chain Assays:  Freelite and N Latex in Diagnosis, Monitoring, and Predicting Survival in Light Chain Amyloidosis.

PubMed

Mahmood, Shameem; Wassef, Nancy L; Salter, Simon J; Sachchithanantham, Sajitha; Lane, T; Foard, D; Whelan, Carol J; Lachmann, Helen J; Gillmore, Julian D; Hawkins, Philip N; Wechalekar, Ashutosh D

2016-07-01

Measurement of serum free light chains (FLCs) is critical in diagnosis, prognosis, and monitoring treatment responses in light chain (AL) amyloidosis. We compare the Freelite assay (polyclonal antibodies to hidden light chain epitopes), which is the current gold standard, with a new assay: a mixture of monoclonal antibodies to light chain epitopes (N Latex). We collected 240 serum samples from 94 consecutive patients with newly diagnosed AL amyloidosis (at least three serial serum samples during the first 6 months) analyzed at the National Amyloidosis Centre, London, from January 2011 to April 2012. Concordance in detecting abnormal light chain components and hematologic response was assessed at 2, 4, and 6 months. The κ and λ clonal light chain involvement was 21% and 79%, respectively, with an abnormal κ/λ ratio or detectable protein in 78.7%. Median κ, λ, and difference in involved and uninvolved FLCs by Freelite and N Latex assays were 17.3 vs 16 mg/L (R(2 ) = 0.91), 48.8 vs 52.6 mg/L (R(2) = 0.52), and 43.2 vs 39.1 mg/L, respectively. Discordant κ/λ ratios at presentation were as follows: 10 of 90 abnormal by Freelite/normal by N Latex and 11 of 90 abnormal by N Latex/normal by Freelite. Both FLC assays show good correlation in detecting the abnormal light chain subtype with discordance in absolute values and thus are not interchangeable. © American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Assessment of Intrathecal Free Light Chain Synthesis: Comparison of Different Quantitative Methods with the Detection of Oligoclonal Free Light Chains by Isoelectric Focusing and Affinity-Mediated Immunoblotting.

PubMed

Zeman, David; Kušnierová, Pavlína; Švagera, Zdeněk; Všianský, František; Byrtusová, Monika; Hradílek, Pavel; Kurková, Barbora; Zapletalová, Olga; Bartoš, Vladimír

2016-01-01

We aimed to compare various methods for free light chain (fLC) quantitation in cerebrospinal fluid (CSF) and serum and to determine whether quantitative CSF measurements could reliably predict intrathecal fLC synthesis. In addition, we wished to determine the relationship between free kappa and free lambda light chain concentrations in CSF and serum in various disease groups. We analysed 166 paired CSF and serum samples by at least one of the following methods: turbidimetry (Freelite™, SPAPLUS), nephelometry (N Latex FLC™, BN ProSpec), and two different (commercially available and in-house developed) sandwich ELISAs. The results were compared with oligoclonal fLC detected by affinity-mediated immunoblotting after isoelectric focusing. Although the correlations between quantitative methods were good, both proportional and systematic differences were discerned. However, no major differences were observed in the prediction of positive oligoclonal fLC test. Surprisingly, CSF free kappa/free lambda light chain ratios were lower than those in serum in about 75% of samples with negative oligoclonal fLC test. In about a half of patients with multiple sclerosis and clinically isolated syndrome, profoundly increased free kappa/free lambda light chain ratios were found in the CSF. Our results show that using appropriate method-specific cut-offs, different methods of CSF fLC quantitation can be used for the prediction of intrathecal fLC synthesis. The reason for unexpectedly low free kappa/free lambda light chain ratios in normal CSFs remains to be elucidated. Whereas CSF free kappa light chain concentration is increased in most patients with multiple sclerosis and clinically isolated syndrome, CSF free lambda light chain values show large interindividual variability in these patients and should be investigated further for possible immunopathological and prognostic significance.

Inhibition of the protease activity of the light chain of type A botulinum neurotoxin by aqueous extract from stinging nettle (Urtica dioica) leaf.

PubMed

Gul, Nizamettin; Ahmed, S Ashraf; Smith, Leonard A

2004-11-01

We investigated the inhibitory effect of stinging nettle leaf extract on the protease activity of botulinum neurotoxin type A and B light chains. The nettle leaf infusion was fractionated and HPLC-based enzymatic assays were performed to determine the capacity of each fraction to inhibit the protease activity of botulinum neurotoxin type A and B light chains. Assay results demonstrated that a water-soluble fraction obtained from the nettle leaf infusion inhibited type A, but did not inhibit type B light chain protease activity. The inhibition mode of water soluble fraction against protease activity of type A light chain was analyzed and found to be a non-competitive.

A single amino acid substitution in the variable region of the light chain specifically blocks immunoglobulin secretion.

PubMed Central

Dul, J L; Argon, Y

1990-01-01

Although immunoglobulin light chains are usually secreted in association with heavy chains, free light chains can be secreted by lymphocytes. To identify the structural features of light chains that are essential for their secretion, we mutated a conserved sequence in the variable domain of a lambda I light chain. The effects of the mutations on secretion were assayed by transient expression in COS-1 cells. One mutant (AV60), which replaced Ala-60 with Val, was secreted as efficiently as wild-type lambda I by transfected COS-1 cells. This result was not surprising because secreted lambda II chains contain valine in this position. However, a second lambda I mutant (AV60FS62), which replaced Phe-62 with Ser as well as Ala-60 with Val, was not secreted. This mutant was arrested in the endoplasmic reticulum, as judged by immunofluorescence and by its association with a lumenal endoplasmic reticulum protein, immunoglobulin heavy chain binding protein (BiP). The defect in secretion was not due to gross misfolding of the lambda I chain, since cells cotransfected with AV60FS62 and an immunoglobulin heavy chain gene produced functional antigen-binding antibodies. These assembled IgM molecules were still not secreted. Hence, the replacement of Phe-62 with Ser specifically affects a determinant on the lambda I light chain that is necessary for the intracellular transport of this molecule. Images PMID:2122454

[A wrong move in an amateur football player reveals a light chain myeloma].

PubMed

Peyneau, Marine; Nassiri, Shiva; Myara, Anne; Ohana, Salomon; Laplanche, Sophie

2016-01-01

Light chain multiple myeloma is a hematologic malignancy characterized by an excess of tumor plasma cells in the bone marrow and a monoclonal light chain in blood. It is generally diagnosed in patients aged 60-75 years old. Hypercalcemia, anemia, kidney failure, and bone pains are the main clinical and biological signs. Here is an atypical case report about a 30 year-old man who was diagnosed a light chain multiple myeloma. This patient had been suffering from back pain for 5 months. Osteolytic lesions were discovered on X-rays prescribed by the family practitioner. Admitted to the Emergency department, all blood tests showed results within the normal range. The serum protein electrophoresis was also normal. Only the urine analysis showed proteinuria. The urine immunofixation electrophoresis showed a massive κ light chain. The bone marrow aspiration cell count confirmed the myeloma diagnosis with an infiltration of dystrophic plasma cells. The patient was transferred to the hematology ward of Necker Hospital for treatment of light chain myeloma.

Bayesian calibration of the Community Land Model using surrogates

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

Ray, Jaideep; Hou, Zhangshuan; Huang, Maoyi

2014-02-01

We present results from the Bayesian calibration of hydrological parameters of the Community Land Model (CLM), which is often used in climate simulations and Earth system models. A statistical inverse problem is formulated for three hydrological parameters, conditional on observations of latent heat surface fluxes over 48 months. Our calibration method uses polynomial and Gaussian process surrogates of the CLM, and solves the parameter estimation problem using a Markov chain Monte Carlo sampler. Posterior probability densities for the parameters are developed for two sites with different soil and vegetation covers. Our method also allows us to examine the structural errormore » in CLM under two error models. We find that surrogate models can be created for CLM in most cases. The posterior distributions are more predictive than the default parameter values in CLM. Climatologically averaging the observations does not modify the parameters' distributions significantly. The structural error model reveals a correlation time-scale which can be used to identify the physical process that could be contributing to it. While the calibrated CLM has a higher predictive skill, the calibration is under-dispersive.« less

Hamiltonian Monte Carlo acceleration using surrogate functions with random bases.

PubMed

Zhang, Cheng; Shahbaba, Babak; Zhao, Hongkai

2017-11-01

For big data analysis, high computational cost for Bayesian methods often limits their applications in practice. In recent years, there have been many attempts to improve computational efficiency of Bayesian inference. Here we propose an efficient and scalable computational technique for a state-of-the-art Markov chain Monte Carlo methods, namely, Hamiltonian Monte Carlo. The key idea is to explore and exploit the structure and regularity in parameter space for the underlying probabilistic model to construct an effective approximation of its geometric properties. To this end, we build a surrogate function to approximate the target distribution using properly chosen random bases and an efficient optimization process. The resulting method provides a flexible, scalable, and efficient sampling algorithm, which converges to the correct target distribution. We show that by choosing the basis functions and optimization process differently, our method can be related to other approaches for the construction of surrogate functions such as generalized additive models or Gaussian process models. Experiments based on simulated and real data show that our approach leads to substantially more efficient sampling algorithms compared to existing state-of-the-art methods.

Sequence-Based Discovery Demonstrates That Fixed Light Chain Human Transgenic Rats Produce a Diverse Repertoire of Antigen-Specific Antibodies.

PubMed

Harris, Katherine E; Aldred, Shelley Force; Davison, Laura M; Ogana, Heather Anne N; Boudreau, Andrew; Brüggemann, Marianne; Osborn, Michael; Ma, Biao; Buelow, Benjamin; Clarke, Starlynn C; Dang, Kevin H; Iyer, Suhasini; Jorgensen, Brett; Pham, Duy T; Pratap, Payal P; Rangaswamy, Udaya S; Schellenberger, Ute; van Schooten, Wim C; Ugamraj, Harshad S; Vafa, Omid; Buelow, Roland; Trinklein, Nathan D

2018-01-01

We created a novel transgenic rat that expresses human antibodies comprising a diverse repertoire of heavy chains with a single common rearranged kappa light chain (IgKV3-15-JK1). This fixed light chain animal, called OmniFlic, presents a unique system for human therapeutic antibody discovery and a model to study heavy chain repertoire diversity in the context of a constant light chain. The purpose of this study was to analyze heavy chain variable gene usage, clonotype diversity, and to describe the sequence characteristics of antigen-specific monoclonal antibodies (mAbs) isolated from immunized OmniFlic animals. Using next-generation sequencing antibody repertoire analysis, we measured heavy chain variable gene usage and the diversity of clonotypes present in the lymph node germinal centers of 75 OmniFlic rats immunized with 9 different protein antigens. Furthermore, we expressed 2,560 unique heavy chain sequences sampled from a diverse set of clonotypes as fixed light chain antibody proteins and measured their binding to antigen by ELISA. Finally, we measured patterns and overall levels of somatic hypermutation in the full B-cell repertoire and in the 2,560 mAbs tested for binding. The results demonstrate that OmniFlic animals produce an abundance of antigen-specific antibodies with heavy chain clonotype diversity that is similar to what has been described with unrestricted light chain use in mammals. In addition, we show that sequence-based discovery is a highly effective and efficient way to identify a large number of diverse monoclonal antibodies to a protein target of interest.

Interaction between glycosaminoglycans and immunoglobulin light chains.

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

Jiang, X.; Myatt, E.; Lykos, P.

1997-01-01

Amyloidosis is a pathological process in which normally soluble proteins polymerize to form insoluble fibrils (amyloid). Amyloid formation is found in a number of diseases, including Alzheimer's disease, adult-onset diabetes, and light-chain-associated amyloidosis. No pharmaceutical methods currently exist to prevent this process or to remove the fibrils from tissue. The search for treatment and prevention methods is hampered by a limited understanding of the biophysical basis of amyloid formation. Glycosaminoglycans (GAGs) are long, unbranched heteropolysaccharides composed of repeating disaccharide subunits and are known to associate with amyloid fibrils. The interaction of amyloid-associated free light chains with GAGs was tested bymore » both size-exclusion high-performance liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis experiments. The results indicated that heparin 16 000 and chondroitin sulfate B and C precipitated both human intact light chains and recombinant light chain variable domains. Although all light chains interacted with heparin, the strongest interactions were obtained with proteins that had formed amyloid. Molecular modeling indicated the possibility of interaction between heparin and the conserved saddle like surface of the light chain dimer opposite the complementarity-determining segments that form part of the antigen-binding site of a functional antibody. This suggestion might offer a new path to block the aggregation of amyloid-associated light chain proteins, by design of antagonists based on properties of GAG binding. A hexasaccharide was modeled as the basis for a possible antagonist.« less

Critical dosimetry measures and surrogate tools that can facilitate clinical success in PDT (Conference Presentation)

NASA Astrophysics Data System (ADS)

Pogue, Brian W.; Davis, Scott C.; Kanick, Stephen C.; Maytin, Edward V.; Pereira, Stephen P.; Palanisami, Akilan; Hasan, Tayyaba

2016-03-01

Photodynamic therapy can be a highly complex treatment with more than one parameter to control, or in some cases it is easily implemented with little control other than prescribed drug and light values. The role of measured dosimetry as related to clinical adoption has not been as successful as it could have been, and part of this may be from the conflicting goals of advocating for as many measurements as possible for accurate control, versus companies and clinical adopters advocating for as few measurements as possible, to keep it simple. An organized approach to dosimetry selection is required, which shifts from mechanistic measurements in pre-clinical and early phase I trials, towards just those essential dose limiting measurements and a focus on possible surrogate measures in phase II/III trials. This essential and surrogate approach to dosimetry should help successful adoption of clinical PDT if successful. The examples of essential dosimetry points and surrogate dosimetry tools which might be implemented in phase II and higher trials are discussed for solid tissue PDT with verteporfin and skin lesion treatment with aminolevulinc acid.

Serum neurofilament as a predictor of disease worsening and brain and spinal cord atrophy in multiple sclerosis.

PubMed

Barro, Christian; Benkert, Pascal; Disanto, Giulio; Tsagkas, Charidimos; Amann, Michael; Naegelin, Yvonne; Leppert, David; Gobbi, Claudio; Granziera, Cristina; Yaldizli, Özgür; Michalak, Zuzanna; Wuerfel, Jens; Kappos, Ludwig; Parmar, Katrin; Kuhle, Jens

2018-05-30

Neuro-axonal injury is a key factor in the development of permanent disability in multiple sclerosis. Neurofilament light chain in peripheral blood has recently emerged as a biofluid marker reflecting neuro-axonal damage in this disease. We aimed at comparing serum neurofilament light chain levels in multiple sclerosis and healthy controls, to determine their association with measures of disease activity and their ability to predict future clinical worsening as well as brain and spinal cord volume loss. Neurofilament light chain was measured by single molecule array assay in 2183 serum samples collected as part of an ongoing cohort study from 259 patients with multiple sclerosis (189 relapsing and 70 progressive) and 259 healthy control subjects. Clinical assessment, serum sampling and MRI were done annually; median follow-up time was 6.5 years. Brain volumes were quantified by structural image evaluation using normalization of atrophy, and structural image evaluation using normalization of atrophy, cross-sectional, cervical spinal cord volumes using spinal cord image analyser (cordial). Results were analysed using ordinary linear regression models and generalized estimating equation modelling. Serum neurofilament light chain was higher in patients with a clinically isolated syndrome or relapsing remitting multiple sclerosis as well as in patients with secondary or primary progressive multiple sclerosis than in healthy controls (age adjusted P < 0.001 for both). Serum neurofilament light chain above the 90th percentile of healthy controls values was an independent predictor of Expanded Disability Status Scale worsening in the subsequent year (P < 0.001). The probability of Expanded Disability Status Scale worsening gradually increased by higher serum neurofilament light chain percentile category. Contrast enhancing and new/enlarging lesions were independently associated with increased serum neurofilament light chain (17.8% and 4.9% increase per lesion respectively; P < 0.001). The higher the serum neurofilament light chain percentile level, the more pronounced was future brain and cervical spinal volume loss: serum neurofilament light chain above the 97.5th percentile was associated with an additional average loss in brain volume of 1.5% (P < 0.001) and spinal cord volume of 2.5% over 5 years (P = 0.009). Serum neurofilament light chain correlated with concurrent and future clinical and MRI measures of disease activity and severity. High serum neurofilament light chain levels were associated with both brain and spinal cord volume loss. Neurofilament light chain levels are a real-time, easy to measure marker of neuro-axonal injury that is conceptually more comprehensive than brain MRI.

Determination of allergen specificity by heavy chains in grass pollen allergen-specific IgE antibodies.

PubMed

Gadermaier, Elisabeth; Flicker, Sabine; Lupinek, Christian; Steinberger, Peter; Valenta, Rudolf

2013-04-01

Affinity and clonality of allergen-specific IgE antibodies are important determinants for the magnitude of IgE-mediated allergic inflammation. We sought to analyze the contribution of heavy and light chains of human allergen-specific IgE antibodies for allergen specificity and to test whether promiscuous pairing of heavy and light chains with different allergen specificity allows binding and might affect affinity. Ten IgE Fabs specific for 3 non-cross-reactive major timothy grass pollen allergens (Phl p 1, Phl p 2, and Phl p 5) obtained by means of combinatorial cloning from patients with grass pollen allergy were used to construct stable recombinant single chain variable fragments (ScFvs) representing the original Fabs and shuffled ScFvs in which heavy chains were recombined with light chains from IgE Fabs with specificity for other allergens by using the pCANTAB 5 E expression system. Possible ancestor genes for the heavy chain and light chain variable region-encoding genes were determined by using sequence comparison with the ImMunoGeneTics database, and their chromosomal locations were determined. Recombinant ScFvs were tested for allergen specificity and epitope recognition by means of direct and sandwich ELISA, and affinity by using surface plasmon resonance experiments. The shuffling experiments demonstrate that promiscuous pairing of heavy and light chains is possible and maintains allergen specificity, which is mainly determined by the heavy chains. ScFvs consisting of different heavy and light chains exhibited different affinities and even epitope specificity for the corresponding allergen. Our results indicate that allergen specificity of allergen-specific IgE is mainly determined by the heavy chains. Different heavy and light chain pairings in allergen-specific IgE antibodies affect affinity and epitope specificity and thus might influence clinical reactivity to allergens. Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Characterization of the interaction between the heavy and light chains of bovine factor Va.

PubMed

Walker, F J

1992-10-05

Bovine factor Va has been previously been shown to consist of heavy (M(r) = 94,000) and light chains (M(r) = 81,000), that interact in a manner dependent upon the presence of either calcium or manganese ions. In an attempt to understand the mechanism of subunit interaction we have studied the effects of temperature and ions on factor Va stability. The rates of formation of factor Va from isolated chains and dissociation were temperature-dependent with an energy of activation of 6.2 and 1.3 kcal mol-1, respectively. The yield of factor Va from isolated chains was inversely related to the amount of time the chains were incubated at 4 degrees C. Incubation of individual chains revealed that the heavy chain is cold-labile, an effect that is reversible. Manganese ion was observed to prevent the conversion to the inactive form. High salt tends to stabilize the two-chain structure of factor Va, but is inhibitory to its formation from isolated chains. High concentrations of either manganese or calcium ions also inhibited reconstitution of activity. The light chain, in particular, was sensitive to the presence of manganese or calcium ion. Heavy chain that had been cleaved by activated protein C had a weakened interaction with the light chain, and the resulting complex had no procoagulant activity. Cooling of the heavy chain to 4 degrees C enhanced its intrinsic fluorescence. Manganese ion prevented some of this enhancement. The heavy chain fluorescence returned to the room temperature value with a half-life of approximately 10 min. In the presence of manganese ion relaxation was accelerated. The intrinsic fluorescence of activated protein C-cleaved heavy chain was not increased when the temperature was decreased. These data suggest that the heavy chain can exist in two forms. Elevated temperature converts it to a form that can bind ions and have a productive interaction with the light chain. However, conditions that prevent the heavy chain from combining with the light chain also stabilize the two subunit structure, suggesting that the high affinity of the complex is due to conformational changes that occur after chain interaction.

Immunoglobulin light chains, glycosaminoglycans and amyloid.

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

Stevens, F. J.; Kisilevsky, R.; Biosciences Division

2000-03-01

Immunoglobulin light chains are the precursor proteins for fibrils that are formed during primary amyloidosis and in amyloidosis associated with multiple myeloma. As found for the approximately 20 currently described forms of focal, localized, or systemic amyloidoses, light chain-related fibrils extracted from physiological deposits are invariably associated with glycosaminoglycans, predominantly heparan sulfate. Other amyloid-related proteins are either structurally normal, such as g2-microglobulin and islet amyloid polypeptide, fragments of normal proteins such as serum amyloid A protein or the precursor protein of the g peptide involved in Alzheimer's disease, or are inherited forms of single amino acid variants of a normalmore » protein such as found in the familial forms of amyloid associated with transthyretin. In contrast, the primary structures of light chains involved in fibril formation exhibit extensive mutational diversity rendering some proteins highly amyloidogenic and others non-pathological. The interactions between light chains and glycosaminoglycans are also affected by amino acid variation and may influence the clinical course of disease by enhancing fibril stability and contributing to resistance to protease degradation. Relatively little is currently known about the mechanisms by which glycosaminoglycans interact with light chains and light-chain fibrils. It is probable that future studies of this uniquely diverse family of proteins will continue o shed light on the processes of amyloidosis, and contribute as well to a greater understanding of the normal physiological roles of glycosaminoglycans.« less

Actin binding by Hip1 (huntingtin-interacting protein 1) and Hip1R (Hip1-related protein) is regulated by clathrin light chain.

PubMed

Wilbur, Jeremy D; Chen, Chih-Ying; Manalo, Venus; Hwang, Peter K; Fletterick, Robert J; Brodsky, Frances M

2008-11-21

The huntingtin-interacting protein family members (Hip1 and Hip1R in mammals and Sla2p in yeast) link clathrin-mediated membrane traffic to actin cytoskeleton dynamics. Genetic data in yeast have implicated the light chain subunit of clathrin in regulating this link. To test this hypothesis, the biophysical properties of mammalian Hip1 and Hip1R and their interaction with clathrin light chain and actin were analyzed. The coiled-coil domains (clathrin light chain-binding) of Hip1 and Hip1R were found to be stable homodimers with no propensity to heterodimerize in vitro. Homodimers were also predominant in vivo, accounting for cellular segregation of Hip1 and Hip1R functions. Coiled-coil domains of Hip1 and Hip1R differed in their stability and flexibility, correlating with slightly different affinities for clathrin light chain and more markedly with effects of clathrin light chain binding on Hip protein-actin interactions. Clathrin light chain binding induced a compact conformation of both Hip1 and Hip1R and significantly reduced actin binding by their THATCH domains. Thus, clathrin is a negative regulator of Hip-actin interactions. These observations necessarily change models proposed for Hip protein function.

Actin Binding by Hip1 (Huntingtin-interacting Protein 1) and Hip1R (Hip1-related Protein) Is Regulated by Clathrin Light Chain*S⃞

PubMed Central

Wilbur, Jeremy D.; Chen, Chih-Ying; Manalo, Venus; Hwang, Peter K.; Fletterick, Robert J.; Brodsky, Frances M.

2008-01-01

The huntingtin-interacting protein family members (Hip1 and Hip1R in mammals and Sla2p in yeast) link clathrin-mediated membrane traffic to actin cytoskeleton dynamics. Genetic data in yeast have implicated the light chain subunit of clathrin in regulating this link. To test this hypothesis, the biophysical properties of mammalian Hip1 and Hip1R and their interaction with clathrin light chain and actin were analyzed. The coiled-coil domains (clathrin light chain-binding) of Hip1 and Hip1R were found to be stable homodimers with no propensity to heterodimerize in vitro. Homodimers were also predominant in vivo, accounting for cellular segregation of Hip1 and Hip1R functions. Coiled-coil domains of Hip1 and Hip1R differed in their stability and flexibility, correlating with slightly different affinities for clathrin light chain and more markedly with effects of clathrin light chain binding on Hip protein-actin interactions. Clathrin light chain binding induced a compact conformation of both Hip1 and Hip1R and significantly reduced actin binding by their THATCH domains. Thus, clathrin is a negative regulator of Hip-actin interactions. These observations necessarily change models proposed for Hip protein function. PMID:18790740

Pathogenesis of renal failure in multiple myeloma: any role of contrast media?

PubMed

Mussap, Michele; Merlini, Giampaolo

2014-01-01

The spectrum of kidney disease-associated monoclonal immunoglobulin and plasma cell malignancies is remarkably broad and encompasses nearly all nephropathologic entities. Multiple myeloma with kidney impairment at presentation is a medical emergency since the recovery of kidney function is associated with survival benefits. In most cases, kidney impairment may be the first clinical manifestation of malignant plasma cell dyscrasias like multiple myeloma and light chain amyloidosis. Multiple myeloma per se cannot be considered a main risk factor for developing acute kidney injury following intravascular administration of iodinated contrast media. The risk is increased by comorbidities such as chronic kidney disease, diabetes, hypercalcemia, dehydration, and use of nephrotoxic drugs. Before the administration of contrast media, the current recommended laboratory tests for assessing kidney function are serum creatinine measurement and the estimation of glomerular filtration rate by using the CKD-EPI equation. The assessment of Bence Jones proteinuria is unnecessary for evaluating the risk of kidney failure in patients with multiple myeloma, since this test cannot be considered a surrogate biomarker of kidney function.

Pathogenesis of Renal Failure in Multiple Myeloma: Any Role of Contrast Media?

PubMed Central

Mussap, Michele; Merlini, Giampaolo

2014-01-01

The spectrum of kidney disease-associated monoclonal immunoglobulin and plasma cell malignancies is remarkably broad and encompasses nearly all nephropathologic entities. Multiple myeloma with kidney impairment at presentation is a medical emergency since the recovery of kidney function is associated with survival benefits. In most cases, kidney impairment may be the first clinical manifestation of malignant plasma cell dyscrasias like multiple myeloma and light chain amyloidosis. Multiple myeloma per se cannot be considered a main risk factor for developing acute kidney injury following intravascular administration of iodinated contrast media. The risk is increased by comorbidities such as chronic kidney disease, diabetes, hypercalcemia, dehydration, and use of nephrotoxic drugs. Before the administration of contrast media, the current recommended laboratory tests for assessing kidney function are serum creatinine measurement and the estimation of glomerular filtration rate by using the CKD-EPI equation. The assessment of Bence Jones proteinuria is unnecessary for evaluating the risk of kidney failure in patients with multiple myeloma, since this test cannot be considered a surrogate biomarker of kidney function. PMID:24877060

Affinity-reversed-phase liquid chromatography assay to quantitate recombinant antibodies and antibody fragments in fermentation broth.

PubMed

Battersby, J E; Snedecor, B; Chen, C; Champion, K M; Riddle, L; Vanderlaan, M

2001-08-24

An automated dual-column liquid chromatography assay comprised of affinity and reversed-phase separations that quantifies the majority of antibody-related protein species found in crude cell extracts of recombinant origin is described. Although potentially applicable to any antibody preparation, we here use samples of anti-CD18 (Fab'2LZ) and a full-length antibody, anti-tissue factor (anti-TF), from various stages throughout a biopharmaceutical production process to describe the assay details. The targeted proteins were captured on an affinity column containing an anti-light-chain (kappa) Fab antibody (AME5) immobilized on controlled pore glass. The affinity column was placed in-line with a reversed-phase column and the captured components were transferred by elution with dilute acid and subsequently resolved by eluting the reversed-phase column with a shallow acetonitrile gradient. Characterization of the resolved components showed that most antibody fragment preparations contained a light-chain fragment, free light chain, light-chain dimer and multiple forms of Fab'. Analysis of full-length antibody preparations also resolved these fragments as well as a completely assembled form. Co-eluting with the full-length antibody were high-molecular-mass variants that were missing one or both light chains. Resolved components were quantified by comparison with peak areas of similarly treated standards. By comparing the two-dimensional polyacrylamide gel electrophoresis patterns of an Escherichia coli blank run, a production run and the material affinity captured (AME5) from a production run, it was determined that the AME5 antibody captured isoforms of light chain, light chain covalently attached to heavy chain, and truncated light chain isoforms. These forms comprise the bulk of the soluble product-related fragments found in E. coli cell extracts of recombinantly produced antibody fragments.

Ferritin light-chain subunits: key elements for the electron transfer across the protein cage.

PubMed

Carmona, Unai; Li, Le; Zhang, Lianbing; Knez, Mato

2014-12-18

The first specific functionality of the light-chain (L-chain) subunit of the universal iron storage protein ferritin was identified. The electrons released during iron-oxidation were transported across the ferritin cage specifically through the L-chains and the inverted electron transport through the L-chains also accelerated the demineralization of ferritin.

Evaluation of strategies to control Fab light chain dimer during mammalian expression and purification: A universal one-step process for purification of correctly assembled Fab.

PubMed

Spooner, Jennifer; Keen, Jenny; Nayyar, Kalpana; Birkett, Neil; Bond, Nicholas; Bannister, David; Tigue, Natalie; Higazi, Daniel; Kemp, Benjamin; Vaughan, Tristan; Kippen, Alistair; Buchanan, Andrew

2015-07-01

Fabs are an important class of antibody fragment as both research reagents and therapeutic agents. There are a plethora of methods described for their recombinant expression and purification. However, these do not address the issue of excessive light chain production that forms light chain dimers nor do they describe a universal purification strategy. Light chain dimer impurities and the absence of a universal Fab purification strategy present persistent challenges for biotechnology applications using Fabs, particularly around the need for bespoke purification strategies. This study describes methods to address light chain dimer formation during Fab expression and identifies a novel CH 1 affinity resin as a simple and efficient one-step purification for correctly assembled Fab. © 2015 Wiley Periodicals, Inc.

Assessment of Intrathecal Free Light Chain Synthesis: Comparison of Different Quantitative Methods with the Detection of Oligoclonal Free Light Chains by Isoelectric Focusing and Affinity-Mediated Immunoblotting

PubMed Central

Kušnierová, Pavlína; Švagera, Zdeněk; Všianský, František; Byrtusová, Monika; Hradílek, Pavel; Kurková, Barbora; Zapletalová, Olga; Bartoš, Vladimír

2016-01-01

Objectives We aimed to compare various methods for free light chain (fLC) quantitation in cerebrospinal fluid (CSF) and serum and to determine whether quantitative CSF measurements could reliably predict intrathecal fLC synthesis. In addition, we wished to determine the relationship between free kappa and free lambda light chain concentrations in CSF and serum in various disease groups. Methods We analysed 166 paired CSF and serum samples by at least one of the following methods: turbidimetry (Freelite™, SPAPLUS), nephelometry (N Latex FLC™, BN ProSpec), and two different (commercially available and in-house developed) sandwich ELISAs. The results were compared with oligoclonal fLC detected by affinity-mediated immunoblotting after isoelectric focusing. Results Although the correlations between quantitative methods were good, both proportional and systematic differences were discerned. However, no major differences were observed in the prediction of positive oligoclonal fLC test. Surprisingly, CSF free kappa/free lambda light chain ratios were lower than those in serum in about 75% of samples with negative oligoclonal fLC test. In about a half of patients with multiple sclerosis and clinically isolated syndrome, profoundly increased free kappa/free lambda light chain ratios were found in the CSF. Conclusions Our results show that using appropriate method-specific cut-offs, different methods of CSF fLC quantitation can be used for the prediction of intrathecal fLC synthesis. The reason for unexpectedly low free kappa/free lambda light chain ratios in normal CSFs remains to be elucidated. Whereas CSF free kappa light chain concentration is increased in most patients with multiple sclerosis and clinically isolated syndrome, CSF free lambda light chain values show large interindividual variability in these patients and should be investigated further for possible immunopathological and prognostic significance. PMID:27846293

Force decay evaluation of thermoplastic and thermoset elastomeric chains: A mechanical design comparison.

PubMed

Masoud, Ahmed I; Tsay, T Peter; BeGole, Ellen; Bedran-Russo, Ana K

2014-11-01

To compare the following over a period of 8 weeks: (1) force decay between thermoplastic (TP) and thermoset (TS) elastomeric chains; (2) force decay between light (200-g) and heavy (350-g) initial forces; and (3) force decay between direct chains and chain loops (stretched from one pin around the second pin and back to the first pin). TP and TS chains were obtained from American Orthodontics™ (AOTP, AOTS) and ORMCO™ (OrTP, OrTS). Each of the four chain groups was subdivided into four subgroups with 10 specimens per subgroup: (1) direct chains light force, (2) direct chains heavy force, (3) chain loops light force, and (4) chain loops heavy force. The experiment was performed in artificial saliva (pH of 6.75) at 37°C. A significant difference was found between TP and TS chains, with an average mean difference of around 20% more force decay found in the TP chains (P < .001, α  =  .05). There was no significant difference between direct chains and chain loops except in OrTP, in which direct chains showed more force decay. There was also no significant difference in force decay identified when using light vs heavy forces. TS chains decayed less than TP chains, and chain loop retraction was beneficial only when using OrTP chains. Contrary to the interchangeable use of TP and TS chains in the published literature and in clinical practice, this study demonstrates that they perform differently under stress and that a clear distinction should be made between the two.

Identification and partial characterization of a low affinity metal-binding site in the light chain of tetanus toxin.

PubMed

Wright, J F; Pernollet, M; Reboul, A; Aude, C; Colomb, M G

1992-05-05

Tetanus toxin was shown to contain a metal-binding site for zinc and copper. Equilibrium dialysis binding experiments using 65Zn indicated an association constant of 9-15 microM, with one zinc-binding site/toxin molecule. The zinc-binding site was localized to the toxin light chain as determined by binding of 65Zn to the light chain but not to the heavy chain after separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transfer to Immobilon membranes. Copper was an efficient inhibitor of 65Zn binding to tetanus toxin and caused two peptide bond cleavages in the toxin light chain in the presence of ascorbate. These metal-catalyzed oxidative cleavages were inhibited by the presence of zinc. Partial characterization of metal-catalyzed oxidative modifications of a peptide based on a putative metal-binding site (HELIH) in the toxin light chain was used to map the metal-binding site in the protein.

Serum-free light-chain assay: clinical utility and limitations.

PubMed

Bhole, Malini V; Sadler, Ross; Ramasamy, Karthik

2014-09-01

In the last decade, the introduction of the serum-free light-chain (sFLC) assay has been an important advance in the diagnosis and management of plasma cell dyscrasias, particularly monoclonal light-chain diseases. The immunoassay was developed to detect free light chains in serum by using anti-FLC antibodies which specifically recognised epitopes on light chains that were 'hidden' in intact immunoglobulins. Since its introduction in 2001, there have been several publications in the English language literature discussing the clinical utility as well as analytical limitations of the sFLC assay. These studies have highlighted both positive and negative aspects of the assay particularly with regard to its sensitivity and specificity and the technical challenges that can affect its performance. The contribution and significance of the sFLC assay in the management of light-chain myeloma, primary amyloid light-chain (AL) amyloidosis and non-secretory myeloma are well recognised and will be addressed in this review. The aim of this article is to also review the published literature with a view to providing a clear understanding of its utility and limitations in the diagnosis, prognosis and monitoring of plasma dyscrasias including intact immunoglobulin multiple myeloma (MM) and monoclonal gammopathy of unknown significance (MGUS). The increasing interest in using this assay in other haematological conditions will also be briefly discussed. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Use of Trypanosoma equiperdum infected rabbits as a source of splenic mRNA; construction of cDNA clones and identification of a rabbit mu heavy chain clone.

PubMed

Bernstein, K E; Pavirani, A; Alexander, C; Jacobsen, F; Fitzmaurice, L; Mage, R

1983-01-01

Rabbits were infected by Trypanosoma equiperdum and the splenic mRNA was isolated. In vitro translation of this RNA and immunoprecipitation with anti-light chain, anti-heavy chain, anti-mu and anti-VH antibodies demonstrated that T. equiperdum infection elicits large quantities of splenic mRNA encoding mu and kappa chains. The mu and gamma heavy chains and the kappa light chains synthesized in the cell-free translation system were specifically immunoprecipitated by antisera to heavy chain VHa and light chain kappa b allotypes. In vitro labeling of spleen cells from trypanosome-infected animals demonstrated that the biosynthetically labeled IgM has a mu chain of higher molecular weight than the mu chain synthesized by in vitro translation, a difference that is largely abolished when cellular glycosylation is blocked with the antibiotic tunicamycin. Enrichment for heavy chain or light chain mRNA was achieved by fractionating mRNA from trypanosome-infected animals on a sucrose gradient. cDNA clones carrying mu heavy chain sequences were produced using a 'one tube' protocol and identified by cross species hybridization and hybridization selection. Infection of rabbits with T. equiperdum followed by sucrose gradient enrichment of splenic mRNA has provided sufficient quantities of mRNA encoding mu heavy chain suitable for cDNA cloning.

An adaptive sparse-grid high-order stochastic collocation method for Bayesian inference in groundwater reactive transport modeling

NASA Astrophysics Data System (ADS)

Zhang, Guannan; Lu, Dan; Ye, Ming; Gunzburger, Max; Webster, Clayton

2013-10-01

Bayesian analysis has become vital to uncertainty quantification in groundwater modeling, but its application has been hindered by the computational cost associated with numerous model executions required by exploring the posterior probability density function (PPDF) of model parameters. This is particularly the case when the PPDF is estimated using Markov Chain Monte Carlo (MCMC) sampling. In this study, a new approach is developed to improve the computational efficiency of Bayesian inference by constructing a surrogate of the PPDF, using an adaptive sparse-grid high-order stochastic collocation (aSG-hSC) method. Unlike previous works using first-order hierarchical basis, this paper utilizes a compactly supported higher-order hierarchical basis to construct the surrogate system, resulting in a significant reduction in the number of required model executions. In addition, using the hierarchical surplus as an error indicator allows locally adaptive refinement of sparse grids in the parameter space, which further improves computational efficiency. To efficiently build the surrogate system for the PPDF with multiple significant modes, optimization techniques are used to identify the modes, for which high-probability regions are defined and components of the aSG-hSC approximation are constructed. After the surrogate is determined, the PPDF can be evaluated by sampling the surrogate system directly without model execution, resulting in improved efficiency of the surrogate-based MCMC compared with conventional MCMC. The developed method is evaluated using two synthetic groundwater reactive transport models. The first example involves coupled linear reactions and demonstrates the accuracy of our high-order hierarchical basis approach in approximating high-dimensional posteriori distribution. The second example is highly nonlinear because of the reactions of uranium surface complexation, and demonstrates how the iterative aSG-hSC method is able to capture multimodal and non-Gaussian features of PPDF caused by model nonlinearity. Both experiments show that aSG-hSC is an effective and efficient tool for Bayesian inference.

High-resolution melting analysis of sequence variations in the cytidine deaminase gene (CDA) in patients with cancer treated with gemcitabine.

PubMed

Raynal, Caroline; Ciccolini, Joseph; Mercier, Cédric; Boyer, Jean-Christophe; Polge, Anne; Lallemant, Benjamin; Mouzat, Kévin; Lumbroso, Serge; Brouillet, Jean-Paul; Evrard, Alexandre

2010-02-01

Gemcitabine (2',2'-difluorodeoxycytidine) is a major antimetabolite cytotoxic drug with a wide spectrum of activity against solid tumors. Hepatic elimination of gemcitabine depends on a catabolic pathway through a deamination step driven by the enzyme cytidine deaminase (CDA). Severe hematologic toxicity to gemcitabine was reported in patients harboring genetic polymorphisms in CDA gene. High-resolution melting (HRM) analysis of polymerase chain reaction amplicon emerges today as a powerful technique for both genotyping and gene scanning strategies. In this study, 46 DNA samples from gemcitabine-treated patients were subjected to HRM analysis on a LightCycler 480 platform. Residual serum CDA activity was assayed as a surrogate marker for the overall functionality of this enzyme. Genotyping of three well-described single nucleotide polymorphisms in coding region (c.79A>C, c.208G>A and c.435C>T) was successfully achieved by HRM analysis of small polymerase chain reaction fragments, whereas unknown single nucleotide polymorphisms were searched by a gene scanning strategy with longer amplicons (up to 622 bp). The gene scanning strategy allowed us to find a new intronic mutation c.246+37G>A in a female patient displaying marked CDA deficiency and who had an extreme toxic reaction with a fatal outcome to gemcitabine treatment. Our work demonstrates that HRM-based methods, owing to their simplicity, reliability, and speed, are useful tools for diagnosis of CDA deficiency and could be of interest for personalized medicine.

Preferential use of lambda light chains is associated with defective mouse antibody responses to the capsular polysaccharide of Neisseria meningitidis group B.

PubMed

Colino, Jesus; Outschoorn, Ingrid

2004-01-01

The capsular polysaccharide of Neisseria meningitidis group B (CpsB) is a very poor immunogen in mammals; this has been considered to be due to the induction of tolerance to cross-reactive host glycoconjugates. It has hampered the development of an effective vaccine against this meningococcal group for many years. Syngeneic populations have a similar tolerogenic background. Thus, we used the variability in ability to mount CpsB-specific immunoglobulin (Ig) responses of individuals from these populations to reveal underlying mechanisms to tolerance contributing to the poor immunogenicity of CpsB. Here we analyze by ELISA, the individual CpsB-specific Ig response of BALB/c and other syngeneic mice to immunization with intact bacteria, using the distribution of light chains as a direct indicator of the repertoire dynamics of the response. Although approximately 96% of anti-CpsB Ig bear kappa-light chains, BALB/c mouse populations were heterogeneous in the light chain composition of their individual anti-CpsB Ig responses. The proportion of kappa and lambda-light chains used for anti-CpsB Ig was a private characteristic that remained relatively constant, for each individual, through repetitive immunizations regardless of the bacterial stimuli size. Despite the prevalence of individual use of kappa-light chains, 5% of BALB/c mice showed restricted usage of lambda-light chains in their CpsB-specific Ig responses, and an additional 11% use them significantly. The preferential use of lambda-light chains in these mice was strongly associated with defective IgM, and absent or barely detectable IgG anti-CpsB responses even after repetitive bacterial immunization. We conclude that differences in the private repertoire of specific Ig also contribute to mouse unresponsiveness to CpsB.

Recovery Efficiency, False Negative Rate, and Limit of Detection Performance of a Validated Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates

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

Piepel, Gregory F.; Hutchison, Janine R.; Kaiser, Brooke L. D.

The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target amounts (2-500 spores) to positive-control plates and test coupons (2 in × 2 in) of four surface materials (glass, stainless steel, vinyl tile, and plastic). Test results from cultured samples were used to evaluate the effects of surrogate, surface concentration, and surface material on recovery efficiency (RE), false negative rate (FNR), and limit of detection. For RE, surrogate and surface material had statistically significant effects, but concentration did not. Mean REs were the lowest formore » vinyl tile (50.8% with BAS, 40.2% with BG) and the highest for glass (92.8% with BAS, 71.4% with BG). FNR values ranged from 0 to 0.833 for BAS and 0 to 0.806 for BG, with values increasing as concentration decreased in the range tested (0.078 to 19.375 CFU/cm2, where CFU denotes ‘colony forming units’). Surface material also had a statistically significant effect. A FNR-concentration curve was fit for each combination of surrogate and surface material. For both surrogates, the FNR curves tended to be the lowest for glass and highest for vinyl title. The FNR curves for BG tended to be higher than for BAS at lower concentrations, especially for glass. Results using a modified Rapid Viability-Polymerase Chain Reaction (mRV-PCR) analysis method were also obtained. The mRV-PCR results and comparisons to the culture results are discussed in a separate report.« less

Recovery Efficiency, False Negative Rate, and Limit of Detection Performance of a Validated Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates

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

Piepel, Gregory F.; Hutchison, Janine R.; Deatherage Kaiser, Brooke L

The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target amounts (2-500 spores) to positive-control plates and test coupons (2 in. × 2 in.) of four surface materials (glass, stainless steel, vinyl tile, and plastic). Test results from cultured samples were used to evaluate the effects of surrogate, surface concentration, and surface material on recovery efficiency (RE), false negative rate (FNR), and limit of detection. For RE, surrogate and surface material had statistically significant effects, but concentration did not. Mean REs were the lowest formore » vinyl tile (50.8% with BAS, 40.2% with BG) and the highest for glass (92.8% with BAS, 71.4% with BG). FNR values ranged from 0 to 0.833 for BAS and 0 to 0.806 for BG, with values increasing as concentration decreased in the range tested (0.078 to 19.375 CFU/cm 2, where CFU denotes ‘colony forming units’). Surface material also had a statistically significant effect. A FNR-concentration curve was fit for each combination of surrogate and surface material. For both surrogates, the FNR curves tended to be the lowest for glass and highest for vinyl title. The FNR curves for BG tended to be higher than for BAS at lower concentrations, especially for glass. Results using a modified Rapid Viability-Polymerase Chain Reaction (mRV-PCR) analysis method were also obtained. The mRV-PCR results and comparisons to the culture results will be discussed in a subsequent report.« less

[Plasma cell dyscrasias and renal damage].

PubMed

Pasquali, Sonia; Iannuzzella, Francesco; Somenzi, Danio; Mattei, Silvia; Bovino, Achiropita; Corradini, Mattia

2012-01-01

Kidney damage caused by immunoglobulin free light chains in the setting of plasma cell dyscrasias is common and may involve all renal compartments, from the glomerulus to the tubulointerstitium, in a wide variety of histomorphological and clinical patterns. The knowledge of how free light chains can promote kidney injury is growing: they can cause functional changes, be processed and deposited, mediate inflammation, apoptosis and fibrosis, and obstruct nephrons. Each clone of the free light chain is unique and its primary structure and post-translation modification can determine the type of renal disease. Measurement of serum free light chain concentrations and calculation of the serum kappa/lambda ratio, together with renal biopsy, represent essential diagnostic tools. An early and correct diagnosis of renal lesions due to plasma cell dyscrasias will allow early initiation of disease-specific treatment strategies. The treatment of free light chain nephropathies is evolving and knowledge of the pathways that promote renal damage should lead to further therapeutic developments.

Light Chain Cast Nephropathy: Practical Considerations in the Management of Myeloma Kidney-What We Know and What the Future May Hold.

PubMed

Manohar, Sandhya; Nasr, Samih H; Leung, Nelson

2018-05-03

To update and evaluate the current knowledge on pathogenesis and management of light chain cast nephropathy. Light chain cast nephropathy (LCCN) is the leading cause of acute renal failure in patients with multiple myeloma and is currently recognized as a myeloma defining event. The immunoglobulin free light chain plays an integral role in the pathogenesis of LCCN. The level of free light chain (FLC) in the blood and urine is directly associated with the risk of developing LCCN. Recovery of renal function is related to the speed and degree of the serum FLC reduction. Recently, two randomized trials using high cutoff dialyzer for the removal of serum FLC produced different results in terms of renal recovery. FLC plays a key role in the development and resolution of LCCN. Future therapies will aim to rapidly reduce its concentration or interrupt its interaction with Tamm-Horsfall protein.

Characterization of renal amyloid derived from the variable region of the lambda light chain subgroup II.

PubMed Central

Picken, M. M.; Gallo, G.; Buxbaum, J.; Frangione, B.

1986-01-01

Amyloid fibrils were extracted from the kidney of a patient (CHE) shown to have tetramers and dimers of a monoclonal lambda light chain in his serum, and whose bone marrow cells in short-term culture synthesized these forms and a smaller lambda fragment of approximately 10,000 to 12,000 daltons. Biochemical and serologic analysis of a fraction of a size (obtained from amyloid fibrils extracted from the kidney) similar to that synthesized by the bone marrow cells revealed a light chain fragment corresponding to the amino terminal end of the variable region of the lambda light chain subgroup II. The presence of similarly sized short fragments of lambda light chain in both the synthesized and deposited protein suggests that aberrant synthesis and/or proteolytic degradation may play a pathogenetic role in the process of amyloidogenesis. Images Figure 1 PMID:3089021

Somatic coliphages as surrogates for enteroviruses in sludge hygienization treatments.

PubMed

Martín-Díaz, Julia; Casas-Mangas, Raquel; García-Aljaro, Cristina; Blanch, Anicet R; Lucena, Francisco

2016-01-01

Conventional bacterial indicators present serious drawbacks giving information about viral pathogens persistence during sludge hygienization treatments. This calls for the search of alternative viral indicators. Somatic coliphages' (SOMCPH) ability for acting as surrogates for enteroviruses was assessed in 47 sludge samples subjected to novel treatment processes. SOMCPH, infectious enteroviruses and genome copies of enteroviruses were monitored. Only one of these groups, the bacteriophages, was present in the sludge at concentrations that allowed the evaluation of treatment's performance. An indicator/pathogen relationship of 4 log10 (PFU/g dw) was found between SOMCPH and infective enteroviruses and their detection accuracy was assessed. The obtained results and the existence of rapid and standardized methods encourage the inclusion of SOMCPH quantification in future sludge directives. In addition, an existing real-time quantitative polymerase chain reaction (RT-qPCR) for enteroviruses was adapted and applied.

CD86 expression as a surrogate cellular biomarker for pharmacological inhibition of the histone demethylase lysine-specific demethylase 1.

PubMed

Lynch, James T; Cockerill, Mark J; Hitchin, James R; Wiseman, Daniel H; Somervaille, Tim C P

2013-11-01

There is a lack of rapid cell-based assays that read out enzymatic inhibition of the histone demethylase LSD1 (lysine-specific demethylase 1). Through transcriptome analysis of human acute myeloid leukemia THP1 cells treated with a tranylcypromine-derivative inhibitor of LSD1 active in the low nanomolar range, we identified the cell surface marker CD86 as a sensitive surrogate biomarker of LSD1 inhibition. Within 24h of enzyme inhibition, there was substantial and dose-dependent up-regulation of CD86 expression, as detected by quantitative polymerase chain reaction, flow cytometry, and enzyme-linked immunosorbent assay. Thus, the use of CD86 expression may facilitate screening of compounds with putative LSD1 inhibitory activities in cellular assays. Copyright © 2013 Elsevier Inc. All rights reserved.

Impact of competitor species composition on predicting diameter growth and survival rates of Douglas-fir trees in southwestern Oregon

USGS Publications Warehouse

Bravo, Felipe; Hann, D.W.; Maguire, Douglas A.

2001-01-01

Mixed conifer and hardwood stands in southwestern Oregon were studied to explore the hypothesis that competition effects on individual-tree growth and survival will differ according to the species comprising the competition measure. Likewise, it was hypothesized that competition measures should extrapolate best if crown-based surrogates are given preference over diameter-based (basal area based) surrogates. Diameter growth and probability of survival were modeled for individual Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees growing in pure stands. Alternative models expressing one-sided and two-sided competition as a function of either basal area or crown structure were then applied to other plots in which Douglas-fir was mixed with other conifers and (or) hardwood species. Crown-based variables outperformed basal area based variables as surrogates for one-sided competition in both diameter growth and survival probability, regardless of species composition. In contrast, two-sided competition was best represented by total basal area of competing trees. Surrogates reflecting differences in crown morphology among species relate more closely to the mechanics of competition for light and, hence, facilitate extrapolation to species combinations for which no observations are available.

Recurrence network measures for hypothesis testing using surrogate data: Application to black hole light curves

NASA Astrophysics Data System (ADS)

Jacob, Rinku; Harikrishnan, K. P.; Misra, R.; Ambika, G.

2018-01-01

Recurrence networks and the associated statistical measures have become important tools in the analysis of time series data. In this work, we test how effective the recurrence network measures are in analyzing real world data involving two main types of noise, white noise and colored noise. We use two prominent network measures as discriminating statistic for hypothesis testing using surrogate data for a specific null hypothesis that the data is derived from a linear stochastic process. We show that the characteristic path length is especially efficient as a discriminating measure with the conclusions reasonably accurate even with limited number of data points in the time series. We also highlight an additional advantage of the network approach in identifying the dimensionality of the system underlying the time series through a convergence measure derived from the probability distribution of the local clustering coefficients. As examples of real world data, we use the light curves from a prominent black hole system and show that a combined analysis using three primary network measures can provide vital information regarding the nature of temporal variability of light curves from different spectroscopic classes.

Synthetic thrombus model for in vitro studies of laser thrombolysis

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

Hermes, R.E.; Trajkovska, K.

1998-07-01

Laser thrombolysis is the controlled ablation of a thrombus (blood clot) blockage in a living arterial system. Theoretical modeling of the interaction of laser light with thrombi relies on the ability to perform in vitro experiments with well characterized surrogate materials. A synthetic thrombus formulation may offer more accurate results when compared to in vivo clinical experiments. The authors describe the development of new surrogate materials based on formulations incorporating chick egg, guar gum, modified food starch, and a laser light absorbing dye. The sound speed and physical consistency of the materials were very close to porcine (arterial) and humanmore » (venous) thrombi. Photographic and videotape recordings of pulsed dye laser ablation experiments under various experimental conditions were used to evaluate the new material as compared to in vitro tests with human (venous) thrombus. The characteristics of ablation and mass removal were similar to that of real thrombi, and therefore provide a more realistic model for in vitro laser thrombolysis when compared to gelatin.« less

Light chain typing of immunoglobulins in small samples of biological material

PubMed Central

Rádl, J.

1970-01-01

A method is described for the typing of the light chains of immunoglobulins in small samples of sera or external secretions and without their previous isolation. It consists of immunoelectrophoresis in agar plates which contain specific antisera against one of the light chain types. All immunoglobulins of this type are thus selected by precipitation in the central area during the electrophoretic phase. Immunoglobulins of the opposite light chain type diffuse through the agar and react with the class specific antisera from the troughs. This results in the precipitin lines as in conventional immunoelectrophoresis. This technique has proved most useful for typing heterogenous or homogeneous immunoglobulins in normal and low concentration. The antisera used for incorporation in the agar should fulfil special requirements. They should contain a high level of antibodies against common surface determinants of the immunoglobulin light chains. The further possibilities of this immunoselection technique for typing different protein mixtures is discussed. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5FIG. 6 PMID:4098592

Serum-free light-chain analysis in diagnosis and management of multiple myeloma and related conditions.

PubMed

Milani, Paolo; Palladini, Giovanni; Merlini, Giampaolo

2016-01-01

The introduction of the serum-free light-chain (S-FLC) assay has been a breakthrough in the diagnosis and management of plasma cell dyscrasias, particularly monoclonal light-chain diseases. The first method, proposed in 2001, quantifies serum-free light-chains using polyclonal antibodies. More recently, assays based on monoclonal antibodies have entered into clinical practice. S-FLC measurement plays a central role in the screening for multiple myeloma and related conditions, in association with electrophoretic techniques. Analysis of S-FLC is essential in assessing the risk of progression of precursor diseases to overt plasma cell dyscrasias. It is also useful for risk stratification in solitary plasmacytoma and AL amyloidosis. The S-FLC measurement is part of the new diagnostic criteria for multiple myeloma, and provides a marker to follow changes in clonal substructure over time. Finally, the evaluation of S-FLC is fundamental for assessing the response to treatment in monoclonal light chain diseases.

Myosin Light Chain Kinase Is Necessary for Tonic Airway Smooth Muscle Contraction*

PubMed Central

Zhang, Wen-Cheng; Peng, Ya-Jing; Zhang, Gen-Sheng; He, Wei-Qi; Qiao, Yan-Ning; Dong, Ying-Ying; Gao, Yun-Qian; Chen, Chen; Zhang, Cheng-Hai; Li, Wen; Shen, Hua-Hao; Ning, Wen; Kamm, Kristine E.; Stull, James T.; Gao, Xiang; Zhu, Min-Sheng

2010-01-01

Different interacting signaling modules involving Ca2+/calmodulin-dependent myosin light chain kinase, Ca2+-independent regulatory light chain phosphorylation, myosin phosphatase inhibition, and actin filament-based proteins are proposed as specific cellular mechanisms involved in the regulation of smooth muscle contraction. However, the relative importance of specific modules is not well defined. By using tamoxifen-activated and smooth muscle-specific knock-out of myosin light chain kinase in mice, we analyzed its role in tonic airway smooth muscle contraction. Knock-out of the kinase in both tracheal and bronchial smooth muscle significantly reduced contraction and myosin phosphorylation responses to K+-depolarization and acetylcholine. Kinase-deficient mice lacked bronchial constrictions in normal and asthmatic airways, whereas the asthmatic inflammation response was not affected. These results indicate that myosin light chain kinase acts as a central participant in the contractile signaling module of tonic smooth muscle. Importantly, contractile airway smooth muscles are necessary for physiological and asthmatic airway resistance. PMID:20018858

Surrogate mother - praiseworthy or stigmatized: a qualitative study on perceptions of surrogacy in Assam, India.

PubMed

Arvidsson, Anna; Vauquline, Polly; Johnsdotter, Sara; Essén, Birgitta

2017-01-01

Surrogacy is a reproductive practice that has been strongly marketed in India as a solution for childless couples. As a result, the number of surrogacy clinics is increasing. Meanwhile, a global discourse on surrogacy, originating from a Western perspective, has characterized surrogacy as being exploitative of women in low-income settings, where poverty drives them to become surrogate mothers. This study explored perspectives on surrogacy from men and women in Assam, an Indian state known to be a low-income setting. Surrogacy arrangements in Assam are still uncommon. It can be expected that the dominant global discourses on surrogacy will be unfamiliar to the general population, and the objective was also to position the results within the divergent global discourses of surrogacy.  In order to explore local views on surrogacy, we conducted individual interviews and focus group discussions with people from various socioeconomic groups in Assam. Our findings reveal that people in Assam perceive surrogacy as a good option for a childless couple, as it would result in a child who is a 'blood' relation - something highly desirable for sociocultural reasons. However, the part played by the surrogate mother complicates local views on surrogacy. Most people consider payment to the surrogate mother contrary to societal norms. A surrogate mother is also often judged in a moral light, either as a 'bad mother' for selling her child, or as a 'noble woman' who has helped a childless couple and deserves payment for her services. In order to decrease the stigmatization of women, a regulatory policy is needed that will take into account the complex understandings of surrogacy and perceptions of surrogate mothers in Indian society. In policy, the possible effect of the dominant exploitation discourse needs to be modulated by local understandings of this reproduction method.

Modular Construction of Large Non-Immune Human Antibody Phage-Display Libraries from Variable Heavy and Light Chain Gene Cassettes.

PubMed

Lee, Nam-Kyung; Bidlingmaier, Scott; Su, Yang; Liu, Bin

2018-01-01

Monoclonal antibodies and antibody-derived therapeutics have emerged as a rapidly growing class of biological drugs for the treatment of cancer, autoimmunity, infection, and neurological diseases. To support the development of human antibodies, various display techniques based on antibody gene repertoires have been constructed over the last two decades. In particular, scFv-antibody phage display has been extensively utilized to select lead antibodies against a variety of target antigens. To construct a scFv phage display that enables efficient antibody discovery, and optimization, it is desirable to develop a system that allows modular assembly of highly diverse variable heavy chain and light chain (Vκ and Vλ) repertoires. Here, we describe modular construction of large non-immune human antibody phage-display libraries built on variable gene cassettes from heavy chain and light chain repertoires (Vκ- and Vλ-light can be made into independent cassettes). We describe utility of such libraries in antibody discovery and optimization through chain shuffling.

Characterization of Non-Infectious Virus-Like Particle Surrogates for Viral Clearance Applications.

PubMed

Johnson, Sarah; Brorson, Kurt A; Frey, Douglas D; Dhar, Arun K; Cetlin, David A

2017-09-01

Viral clearance is a critical aspect of biopharmaceutical manufacturing process validation. To determine the viral clearance efficacy of downstream chromatography and filtration steps, live viral "spiking" studies are conducted with model mammalian viruses such as minute virus of mice (MVM). However, due to biosafety considerations, spiking studies are costly and typically conducted in specialized facilities. In this work, we introduce the concept of utilizing a non-infectious MVM virus-like particle (MVM-VLP) as an economical surrogate for live MVM during process development and characterization. Through transmission electron microscopy, size exclusion chromatography with multi-angle light scattering, chromatofocusing, and a novel solute surface hydrophobicity assay, we examined and compared the size, surface charge, and hydrophobic properties of MVM and MVM-VLP. The results revealed that MVM and MVM-VLP exhibited nearly identical physicochemical properties, indicating the potential utility of MVM-VLP as an accurate and economical surrogate to live MVM during chromatography and filtration process development and characterization studies.

Multiple Myeloma and Its Precursor Disease Among Firefighters Exposed to the World Trade Center Disaster.

PubMed

Landgren, Ola; Zeig-Owens, Rachel; Giricz, Orsolya; Goldfarb, David; Murata, Kaznouri; Thoren, Katie; Ramanathan, Lakshmi; Hultcrantz, Malin; Dogan, Ahmet; Nwankwo, George; Steidl, Ulrich; Pradhan, Kith; Hall, Charles B; Cohen, Hillel W; Jaber, Nadia; Schwartz, Theresa; Crowley, Laura; Crane, Michael; Irby, Shani; Webber, Mayris P; Verma, Amit; Prezant, David J

2018-06-01

The World Trade Center (WTC) attacks on September 11, 2001, created an unprecedented environmental exposure to known and suspected carcinogens suggested to increase the risk of multiple myeloma. Multiple myeloma is consistently preceded by the precursor states of monoclonal gammopathy of undetermined significance (MGUS) and light-chain MGUS, detectable in peripheral blood. To characterize WTC-exposed firefighters with a diagnosis of multiple myeloma and to conduct a screening study for MGUS and light-chain MGUS. Case series of multiple myeloma in firefighters diagnosed between September 11, 2001, and July 1, 2017, together with a seroprevalence study of MGUS in serum samples collected from Fire Department of the City of New York (FDNY) firefighters between December 2013 and October 2015. Participants included all WTC-exposed FDNY white, male firefighters with a confirmed physician diagnosis of multiple myeloma (n = 16) and WTC-exposed FDNY white male firefighters older than 50 years with available serum samples (n = 781). WTC exposure defined as rescue and/or recovery work at the WTC site between September 11, 2001, and July 25, 2002. Multiple myeloma case information, and age-adjusted and age-specific prevalence rates for overall MGUS (ie, MGUS and light-chain MGUS), MGUS, and light-chain MGUS. Sixteen WTC-exposed white male firefighters received a diagnosis of multiple myeloma after September 11, 2001; median age at diagnosis was 57 years (interquartile range, 50-68 years). Serum/urine monoclonal protein isotype/free light-chain data were available for 14 cases; 7 (50%) had light-chain multiple myeloma. In a subset of 7 patients, myeloma cells were assessed for CD20 expression; 5 (71%) were CD20 positive. In the screening study, we assayed peripheral blood from 781 WTC-exposed firefighters. The age-standardized prevalence rate of MGUS and light-chain MGUS combined was 7.63 per 100 persons (95% CI, 5.45-9.81), 1.8-fold higher than rates from the Olmsted County, Minnesota, white male reference population (relative rate, 1.76; 95% CI, 1.34-2.29). The age-standardized prevalence rate of light-chain MGUS was more than 3-fold higher than in the same reference population (relative rate, 3.13; 95% CI, 1.99-4.93). Environmental exposure to the WTC disaster site is associated with myeloma precursor disease (MGUS and light-chain MGUS) and may be a risk factor for the development of multiple myeloma at an earlier age, particularly the light-chain subtype.

Characterizing Chain Processes in Visible Light Photoredox Catalysis

PubMed Central

Cismesia, Megan A.

2015-01-01

The recognition that Ru(bpy)32+ andsimilar visible light absorbing transition metal complexes can be photocatalysts for a variety of synthetically useful organic reactions has resulted in a recent resurgence of interest in photoredox catalysis. However, many of the critical mechanistic aspects of this class of reactions remain poorly understood. In particular, the degree to which visible light photoredox reactions involve radical chain processes has been a point of some disagreement that has not been subjected to systematic analysis. We have now performed quantum yield measurements to demonstrate that threerepresentative, mechanistically distinct photoredox processes involve product-forming chain reactions. Moreover, we show that the combination of quantum yield and luminescence quenching experiments provides a rapid method to estimate the length of these chains. Together, these measurements constitute a robust, operationally facile strategy for characterizing chain processes in a wide range of visible light photoredox reactions. PMID:26668708

Therapeutic Approaches for Botulinum Intoxication Targeting Degradation of the Light Chain

DTIC Science & Technology

2013-04-01

SUBJECT TERMS Botulinum toxin , ubiquitin, chimeric toxin light chains, LcA, LcE, Yeast 2 hybrid, intracellular therapy. 16. SECURITY...Synaptic Research will develop dichain hybrids consisting of Clostridium botulinum toxin light chains (LCs) from serotypes A (long-lived) and E...stability to LCs of botulinum toxin can be assessed by mutation of dileucine residues and systematic deletion of residues from LcA-LcE chimeras to provide a

Smooth muscle myosin light chain kinase efficiently phosphorylates serine 15 of cardiac myosin regulatory light chain

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

Josephson, Matthew P.; Sikkink, Laura A.; Penheiter, Alan R.

2011-12-16

Highlights: Black-Right-Pointing-Pointer Cardiac myosin regulatory light chain (MYL2) is phosphorylated at S15. Black-Right-Pointing-Pointer Smooth muscle myosin light chain kinase (smMLCK) is a ubiquitous kinase. Black-Right-Pointing-Pointer It is a widely believed that MYL2 is a poor substrate for smMLCK. Black-Right-Pointing-Pointer In fact, smMLCK efficiently and rapidly phosphorylates S15 in MYL2. Black-Right-Pointing-Pointer Phosphorylation kinetics measured by novel fluorescence method without radioactivity. -- Abstract: Specific phosphorylation of the human ventricular cardiac myosin regulatory light chain (MYL2) modifies the protein at S15. This modification affects MYL2 secondary structure and modulates the Ca{sup 2+} sensitivity of contraction in cardiac tissue. Smooth muscle myosin light chainmore » kinase (smMLCK) is a ubiquitous kinase prevalent in uterus and present in other contracting tissues including cardiac muscle. The recombinant 130 kDa (short) smMLCK phosphorylated S15 in MYL2 in vitro. Specific modification of S15 was verified using the direct detection of the phospho group on S15 with mass spectrometry. SmMLCK also specifically phosphorylated myosin regulatory light chain S15 in porcine ventricular myosin and chicken gizzard smooth muscle myosin (S20 in smooth muscle) but failed to phosphorylate the myosin regulatory light chain in rabbit skeletal myosin. Phosphorylation kinetics, measured using a novel fluorescence method eliminating the use of radioactive isotopes, indicates similar Michaelis-Menten V{sub max} and K{sub M} for regulatory light chain S15 phosphorylation rates in MYL2, porcine ventricular myosin, and chicken gizzard myosin. These data demonstrate that smMLCK is a specific and efficient kinase for the in vitro phosphorylation of MYL2, cardiac, and smooth muscle myosin. Whether smMLCK plays a role in cardiac muscle regulation or response to a disease causing stimulus is unclear but it should be considered a potentially significant kinase in cardiac tissue on the basis of its specificity, kinetics, and tissue expression.« less

Targeting Stereotyped B Cell Receptors from Chronic Lymphocytic Leukemia Patients with Synthetic Antigen Surrogates.

PubMed

Sarkar, Mohosin; Liu, Yun; Qi, Junpeng; Peng, Haiyong; Morimoto, Jumpei; Rader, Christoph; Chiorazzi, Nicholas; Kodadek, Thomas

2016-04-01

Chronic lymphocytic leukemia (CLL) is a disease in which a single B-cell clone proliferates relentlessly in peripheral lymphoid organs, bone marrow, and blood. DNA sequencing experiments have shown that about 30% of CLL patients have stereotyped antigen-specific B-cell receptors (BCRs) with a high level of sequence homology in the variable domains of the heavy and light chains. These include many of the most aggressive cases that haveIGHV-unmutated BCRs whose sequences have not diverged significantly from the germ line. This suggests a personalized therapy strategy in which a toxin or immune effector function is delivered selectively to the pathogenic B-cells but not to healthy B-cells. To execute this strategy, serum-stable, drug-like compounds able to target the antigen-binding sites of most or all patients in a stereotyped subset are required. We demonstrate here the feasibility of this approach with the discovery of selective, high affinity ligands for CLL BCRs of the aggressive, stereotyped subset 7P that cross-react with the BCRs of several CLL patients in subset 7p, but not with BCRs from patients outside this subset. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Neurofilament light chain and oligoclonal bands are prognostic biomarkers in radiologically isolated syndrome.

PubMed

Matute-Blanch, Clara; Villar, Luisa M; Álvarez-Cermeño, José C; Rejdak, Konrad; Evdoshenko, Evgeniy; Makshakov, Gleb; Nazarov, Vladimir; Lapin, Sergey; Midaglia, Luciana; Vidal-Jordana, Angela; Drulovic, Jelena; García-Merino, Antonio; Sánchez-López, Antonio J; Havrdova, Eva; Saiz, Albert; Llufriu, Sara; Alvarez-Lafuente, Roberto; Schroeder, Ina; Zettl, Uwe K; Galimberti, Daniela; Ramió-Torrentà, Lluís; Robles, René; Quintana, Ester; Hegen, Harald; Deisenhammer, Florian; Río, Jordi; Tintoré, Mar; Sánchez, Alex; Montalban, Xavier; Comabella, Manuel

2018-04-01

The prognostic role of cerebrospinal fluid molecular biomarkers determined in early pathogenic stages of multiple sclerosis has yet to be defined. In the present study, we aimed to investigate the prognostic value of chitinase 3 like 1 (CHI3L1), neurofilament light chain, and oligoclonal bands for conversion to clinically isolated syndrome and to multiple sclerosis in 75 patients with radiologically isolated syndrome. Cerebrospinal fluid levels of CHI3L1 and neurofilament light chain were measured by enzyme-linked immunosorbent assay. Uni- and multivariable Cox regression models including as covariates age at diagnosis of radiologically isolated syndrome, number of brain lesions, sex and treatment were used to investigate associations between cerebrospinal fluid CHI3L1 and neurofilament light chain levels and time to conversion to clinically isolated syndrome and multiple sclerosis. Neurofilament light chain levels and oligoclonal bands were independent risk factors for the development of clinically isolated syndrome (hazard ratio = 1.02, P = 0.019, and hazard ratio = 14.7, P = 0.012, respectively) and multiple sclerosis (hazard ratio = 1.03, P = 0.003, and hazard ratio = 8.9, P = 0.046, respectively). The best cut-off to classify cerebrospinal fluid neurofilament light chain levels into high and low was 619 ng/l, and high neurofilament light chain levels were associated with a trend to shorter time to clinically isolated syndrome (P = 0.079) and significant shorter time to multiple sclerosis (P = 0.017). Similarly, patients with radiologically isolated syndrome presenting positive oligoclonal bands converted faster to clinically isolated syndrome and multiple sclerosis (P = 0.005 and P = 0.008, respectively). The effects of high neurofilament light chain levels shortening time to clinically isolated syndrome and multiple sclerosis were more pronounced in radiologically isolated syndrome patients with ≥37 years compared to younger patients. Cerebrospinal fluid CHI3L1 levels did not influence conversion to clinically isolated syndrome and multiple sclerosis in radiologically isolated syndrome patients. Overall, these findings suggest that cerebrospinal neurofilament light chain levels and oligoclonal bands are independent predictors of clinical conversion in patients with radiologically isolated syndrome. The association with a faster development of multiple sclerosis reinforces the importance of cerebrospinal fluid analysis in patients with radiologically isolated syndrome.

Microscopic theory of light-induced deformation in amorphous side-chain azobenzene polymers.

PubMed

Toshchevikov, V; Saphiannikova, M; Heinrich, G

2009-04-16

We propose a microscopic theory of light-induced deformation of side-chain azobenzene polymers taking into account the internal structure of polymer chains. Our theory is based on the fact that interaction of chromophores with the polarized light leads to the orientation anisotropy of azobenzene macromolecules which is accompanied by the appearance of mechanical stress. It is the first microscopic theory which provides the value of the light-induced stress larger than the yield stress. This result explains a possibility for the inscription of surface relief gratings in glassy side-chain azobenzene polymers. For some chemical architectures, elongation of a sample demonstrates a nonmonotonic behavior with the light intensity and can change its sign (a stretched sample starts to be uniaxially compressed), in agreement with experiments. Using a viscoplastic approach, we show that the irreversible strain of a sample, which remains after the light is switched off, decreases with increasing temperature and can disappear at certain temperature below the glass transition temperature. This theoretical prediction is also confirmed by recent experiments.

Compositional and expression analyses of the glideosome during the Plasmodium life cycle reveal an additional myosin light chain required for maximum motility

PubMed Central

Green, Judith L.; Wall, Richard J.; Vahokoski, Juha; Yusuf, Noor A.; Ridzuan, Mohd A. Mohd; Stanway, Rebecca R.; Stock, Jessica; Knuepfer, Ellen; Brady, Declan; Martin, Stephen R.; Howell, Steven A.; Pires, Isa P.; Moon, Robert W.; Molloy, Justin E.; Kursula, Inari; Tewari, Rita

2017-01-01

Myosin A (MyoA) is a Class XIV myosin implicated in gliding motility and host cell and tissue invasion by malaria parasites. MyoA is part of a membrane-associated protein complex called the glideosome, which is essential for parasite motility and includes the MyoA light chain myosin tail domain–interacting protein (MTIP) and several glideosome-associated proteins (GAPs). However, most studies of MyoA have focused on single stages of the parasite life cycle. We examined MyoA expression throughout the Plasmodium berghei life cycle in both mammalian and insect hosts. In extracellular ookinetes, sporozoites, and merozoites, MyoA was located at the parasite periphery. In the sexual stages, zygote formation and initial ookinete differentiation precede MyoA synthesis and deposition, which occurred only in the developing protuberance. In developing intracellular asexual blood stages, MyoA was synthesized in mature schizonts and was located at the periphery of segmenting merozoites, where it remained throughout maturation, merozoite egress, and host cell invasion. Besides the known GAPs in the malaria parasite, the complex included GAP40, an additional myosin light chain designated essential light chain (ELC), and several other candidate components. This ELC bound the MyoA neck region adjacent to the MTIP-binding site, and both myosin light chains co-located to the glideosome. Co-expression of MyoA with its two light chains revealed that the presence of both light chains enhances MyoA-dependent actin motility. In conclusion, we have established a system to study the interplay and function of the three glideosome components, enabling the assessment of inhibitors that target this motor complex to block host cell invasion. PMID:28893907

Diagnostic reference range of κ/λ free light chain ratio to screen for Bence Jones proteinuria is not significantly influenced by GFR.

PubMed

Schmidt-Hieltjes, Yvonne; Elshof, Clemens; Roovers, Lian; Ruinemans-Koerts, Janneke

2016-05-01

The aim of our study was to analyse whether the κ/λ free light chain ratio reference range for screening for Bence Jones proteinuria should be dependent on the estimated glomerular filtration rate (eGFR). The serum κ/λ free light chain ratio, eGFR, serum M-protein and Bence Jones protein were measured in 544 patients for whom Bence Jones protein analysis was ordered. In the population of patients without Bence Jones proteinuria or a M-protein (n = 402), there is no gradual increase in κ/λ free light chain ratio with diminishing eGFR. The κ/λ free light chain ratio in this group was 0.56-1.86 (95% interval). With this diagnostic reference range of the κ/λ ratio, 105 of the 110 patients with Bence Jones protein could be identified correctly. Only five patients with Bence Jones proteinuria (<0.17 g/L) were missed, without diagnostic or therapeutic consequences. In 36 patients (6.6%), an abnormal κ/λ free light chain ratio was measured without the presence of Bence Jones proteinuria. A κ/λ free light chain ratio in serum can be used safely and efficiently to select urine samples which should be analysed for Bence Jones proteinuria with an electrophoresis/immunofixation technique. Using this diagnostic reference range, the number of urine samples which should be analysed by electrophoresis/immunofixation could be reduced by 74%. The diagnostic reference interval can be determined best in a group of patients for whom Bence Jones analysis is indicated. For calculation of this reference range, the eGFR value does not need to be taken into account. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Surface IgM λ light chain is involved in the binding and infection of infectious bursal disease virus (IBDV) to DT40 cells.

PubMed

Chi, Jiaqi; You, Leiming; Li, Peipei; Teng, Man; Zhang, Gaiping; Luo, Jun; Wang, Aiping

2018-04-01

Infectious bursal disease virus (IBDV) is an important immunosuppressive virus in chickens. Surface immunoglobulin M (sIgM)-bearing B lymphocytes act as the major targets of IBDV in the bursa of Fabricius, and sIgM may function as one of the membrane binding sites responsible for IBDV infection. Recently, using the virus overlay protein binding assay, the chicken λ light chain of sIgM was identified to specifically interact with IBDV in a virulence-independent manner in vitro. To further investigate sIgM λ light chain-mediated IBDV binding and infection in pre-B cells, the cell line DT40, which is susceptible to both pathogenic and attenuated IBDV, was used. Based on the RNA interference strategy, the DT40 cell line whose λ light chain of sIgM was stably knocked down, herein termed DT40LKD, was generated by the genomic integration of a specific small hairpin RNA and a green fluorescence protein co-expression construct. Flow cytometry analysis indicated that the binding of IBDV to DT40LKD cells was significantly reduced due to the loss of sIgM λ light chain. In particular, reduced viral replication was observed in IBDV-incubated DT40LKD cells, and no viral release into cell culture medium was detected by the IBDV rapid diagnostic strips. In addition, the rescue of sIgM λ light chain expression restored viral binding and replication in DT40LKD cells. These results show that sIgM λ light chain appears to be beneficial for IBDV attachment and infection, suggesting that sIgM acts as a binding site involved in IBDV infection.

Primary CNS Nonamyloidogenic Light Chain Deposition Disease: Case Report and Brief Review.

PubMed

Mercado, Juan Jose; Markert, James M; Meador, William; Chapman, Philip; Perry, Arie; Hackney, James R

2017-12-01

The true incidence of light chain deposition disease (LCDD) restricted to the central nervous system (CNS) is unknown. To our knowledge only 7 cases of LCDD restricted to the brain have been previously reported. We herein describe an unusual example. A 44-year-old man presented with a history of ischemic retinopathy in 2004 and left lower extremity hypoesthesia in 2007 that progressed gradually to left-sided weakness and numbness in the 2 years prior to his hospitalization in 2015. A stereotactic brain biopsy was performed, displaying nonspecific hyaline deposits of amorphous "amyloid-like" material involving deep brain white matter and vessels. These were Congo red negative and were accompanied by a sparse lymphoplasmacytic infiltrate. Plasma cells demonstrated kappa light chain class restriction by chromogenic in situ hybridization (CISH). There was patchy reactivity with kappa immunohistochemistry in the amorphous deposits. A diagnosis of light chain deposition disease was made. Subsequent systemic myeloma and lymphoma workups were negative. Previously reported cases have included men and women, spanning the ages of 19 and 72 years, often presenting with hemiparesis, hypoesthesia, or seizures. Deposits have been reported in the cerebrum and cerebellum. T2/FLAIR (fluid attenuation inversion recovery) changes are usual, but lesions may or may not produce contrast enhancement. The light chain deposition may be of kappa or lambda class. Most lesions have been accompanied by local lymphoid and/or plasma cell infiltrates exhibiting light chain restriction of the same class as the deposits. In summary, LCDD limited to the CNS is a rare lesion consisting of deposition of amyloid-like, but Congo red-negative monotypic light chain usually produced by local lymphoplasmacytic infiltrates.

Pituitary adenylate cyclase-activating polypeptide is a potent inhibitor of the growth of light chain-secreting human multiple myeloma cells.

PubMed

Li, Min; Cortez, Shirley; Nakamachi, Tomoya; Batuman, Vecihi; Arimura, Akira

2006-09-01

Multiple myeloma represents a malignant proliferation of plasma cells in the bone marrow, which often overproduces immunoglobulin light chains. We have shown previously that pituitary adenylate cyclase-activating polypeptide (PACAP) markedly suppresses the release of proinflammatory cytokines from light chain-stimulated human renal proximal tubule epithelial cells and prevents the resulting tubule cell injury. In this study, we have shown that PACAP suppresses the proliferation of human kappa and lambda light chain-secreting multiple myeloma-derived cells. The addition of PACAP suppressed light chain-producing myeloma cell-stimulated interleukin 6 (IL-6) secretion by the bone marrow stromal cells (BMSCs). A specific antagonist to either the human PACAP-specific receptor or the vasoactive intestinal peptide receptor attenuated the suppressive effect of PACAP on IL-6 production in the adhesion of human multiple myeloma cells to BMSCs. The secretion of IL-6 by BMSCs was completely inhibited by 10(-9) mol/L PACAP, which also attenuated the phosphorylation of both p42/44 and p38 mitogen-activated protein kinases (MAPK) as well as nuclear factor-kappaB (NF-kappaB) activation in response to the adhesion of multiple myeloma cells to BMSCs, whereas the inhibition of p42/44 MAPK signaling attenuated PACAP action. The signaling cascades involved in the inhibitory effect of PACAP on IL-6-mediated paracrine stimulation of light chain-secreting myeloma cell growth was mediated through the suppression of p38 MAPK as well as modulation of activation of transcription factor NF-kappaB. These findings suggest that PACAP may be a new antitumor agent that directly suppresses light chain-secreting myeloma cell growth and indirectly affects tumor cell growth by modifying the bone marrow milieu of the multiple myeloma.

Compositional and expression analyses of the glideosome during the Plasmodium life cycle reveal an additional myosin light chain required for maximum motility.

PubMed

Green, Judith L; Wall, Richard J; Vahokoski, Juha; Yusuf, Noor A; Ridzuan, Mohd A Mohd; Stanway, Rebecca R; Stock, Jessica; Knuepfer, Ellen; Brady, Declan; Martin, Stephen R; Howell, Steven A; Pires, Isa P; Moon, Robert W; Molloy, Justin E; Kursula, Inari; Tewari, Rita; Holder, Anthony A

2017-10-27

Myosin A (MyoA) is a Class XIV myosin implicated in gliding motility and host cell and tissue invasion by malaria parasites. MyoA is part of a membrane-associated protein complex called the glideosome, which is essential for parasite motility and includes the MyoA light chain myosin tail domain-interacting protein (MTIP) and several glideosome-associated proteins (GAPs). However, most studies of MyoA have focused on single stages of the parasite life cycle. We examined MyoA expression throughout the Plasmodium berghei life cycle in both mammalian and insect hosts. In extracellular ookinetes, sporozoites, and merozoites, MyoA was located at the parasite periphery. In the sexual stages, zygote formation and initial ookinete differentiation precede MyoA synthesis and deposition, which occurred only in the developing protuberance. In developing intracellular asexual blood stages, MyoA was synthesized in mature schizonts and was located at the periphery of segmenting merozoites, where it remained throughout maturation, merozoite egress, and host cell invasion. Besides the known GAPs in the malaria parasite, the complex included GAP40, an additional myosin light chain designated essential light chain (ELC), and several other candidate components. This ELC bound the MyoA neck region adjacent to the MTIP-binding site, and both myosin light chains co-located to the glideosome. Co-expression of MyoA with its two light chains revealed that the presence of both light chains enhances MyoA-dependent actin motility. In conclusion, we have established a system to study the interplay and function of the three glideosome components, enabling the assessment of inhibitors that target this motor complex to block host cell invasion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Treatment of Acute Renal Failure Secondary to Multiple Myeloma with Chemotherapy and Extended High Cut-Off Hemodialysis

PubMed Central

Hutchison, Colin A.; Bradwell, Arthur R.; Cook, Mark; Basnayake, Kolitha; Basu, Supratik; Harding, Stephen; Hattersley, John; Evans, Neil D.; Chappel, Mike J.; Sampson, Paul; Foggensteiner, Lukas; Adu, Dwomoa; Cockwell, Paul

2009-01-01

Background and objectives: Extended hemodialysis using a high cut-off dialyzer (HCO-HD) removes large quantities of free light chains in patients with multiple myeloma. However, the clinical utility of this method is uncertain. This study assessed the combination of chemotherapy and HCO-HD on serum free light chain concentrations and renal recovery in patients with myeloma kidney (cast nephropathy) and dialysis-dependent acute renal failure. Design, setting, participants, & measurements: An open-label study of the relationship between free light chain levels and clinical outcomes in 19 patients treated with standard chemotherapy regimens and HCO-HD. Results: There were sustained early reductions in serum free light chain concentrations (median 85% [range 50 to 97]) in 13 patients. These 13 patients became dialysis independent at a median of 27 d (range 13 to 120). Six patients had chemotherapy interrupted because of early infections and did not achieve sustained early free light chain reductions; one of these patients recovered renal function (at 105 d) the remaining 5 patients did not recover renal function. Patients who recovered renal function had a significantly improved survival (P < 0.012). Conclusion: In dialysis-dependent acute renal failure secondary to myeloma kidney, patients who received uninterrupted chemotherapy and extended HCO-HD had sustained reductions in serum free light chain concentrations and recovered independent renal function. PMID:19339414

Disulfide oil hazard assessment using categorical analysis and a mode of action determination.

PubMed

Morgott, David; Lewis, Christopher; Bootman, James; Banton, Marcy

2014-01-01

Diethyl and diphenyl disulfides, naphtha sweetening (Chemical Abstracts Service [CAS] # 68955-96-4), are primarily composed of low-molecular-weight dialkyl disulfides extracted from C4 to C5 light hydrocarbon streams during the refining of crude oil. The substance, commonly known as disulfide oil (DSO), can be composed of up to 17 different disulfides and trisulfides with monoalkyl chain lengths no greater than C4. The disulfides in DSO constitute a homologous series of chemical constituents that are perfectly suited for a hazard evaluation using a read-across/worst-case approach. The DSO constituents exhibit a common mode of action that is operable at all trophic levels. The observed oxidative stress response is mediated by reactive oxygen species and free radical intermediates generated after disulfide bond cleavage and subsequent redox cycling of the resulting mercaptan. Evidence indicates that the lowest series member, dimethyl disulfide (DMDS), can operate as a worst-case surrogate for other members of the series, since it displays the highest toxicity. Increasing the alkyl chain length or degree of substitution has been shown to serially reduce disulfide toxicity through resonance stabilization of the radical intermediate or steric inhibition of the initial enzymatic step. The following case study examines the mode of action for dialkyl disulfide toxicity and documents the use of read-across information from DMDS to assess the hazards of DSO. The results indicate that DSO possesses high aquatic toxicity, moderate environmental persistence, low to moderate acute toxicity, high repeated dose toxicity, and a low potential for genotoxicity, carcinogenicity, and reproductive/developmental effects.

Immunoglobulin light chain allelic inclusion in systemic lupus erythematosus

PubMed Central

Fraser, Louise D.; Zhao, Yuan; Lutalo, Pamela M. K.; D'Cruz, David P.; Cason, John; Silva, Joselli S.; Dunn‐Walters, Deborah K.; Nayar, Saba; Cope, Andrew P.

2015-01-01

The principles of allelic exclusion state that each B cell expresses a single light and heavy chain pair. Here, we show that B cells with both kappa and lambda light chains (Igκ and Igλ) are enriched in some patients with the systemic autoimmune disease systemic lupus erythematosus (SLE), but not in the systemic autoimmune disease control granulomatosis with polyangiitis. Detection of dual Igκ and Igλ expression by flow cytometry could not be abolished by acid washing or by DNAse treatment to remove any bound polyclonal antibody or complexes, and was retained after two days in culture. Both surface and intracytoplasmic dual light chain expression was evident by flow cytometry and confocal microscopy. We observed reduced frequency of rearrangements of the kappa‐deleting element (KDE) in SLE and an inverse correlation between the frequency of KDE rearrangement and the frequency of dual light chain expressing B cells. We propose that dual expression of Igκ and Igλ by a single B cell may occur in some patients with SLE when this may be a consequence of reduced activity of the KDE. PMID:26036683

Myosin conformational states determined by single fluorophore polarization

PubMed Central

Warshaw, David M.; Hayes, Eric; Gaffney, Donald; Lauzon, Anne-Marie; Wu, Junru; Kennedy, Guy; Trybus, Kathleen; Lowey, Susan; Berger, Christopher

1998-01-01

Muscle contraction is powered by the interaction of the molecular motor myosin with actin. With new techniques for single molecule manipulation and fluorescence detection, it is now possible to correlate, within the same molecule and in real time, conformational states and mechanical function of myosin. A spot-confocal microscope, capable of detecting single fluorophore polarization, was developed to measure orientational states in the smooth muscle myosin light chain domain during the process of motion generation. Fluorescently labeled turkey gizzard smooth muscle myosin was prepared by removal of endogenous regulatory light chain and re-addition of the light chain labeled at cysteine-108 with the 6-isomer of iodoacetamidotetramethylrhodamine (6-IATR). Single myosin molecule fluorescence polarization data, obtained in a motility assay, provide direct evidence that the myosin light chain domain adopts at least two orientational states during the cyclic interaction of myosin with actin, a randomly disordered state, most likely associated with myosin whereas weakly bound to actin, and an ordered state in which the light chain domain adopts a finite angular orientation whereas strongly bound after the powerstroke. PMID:9653135

Surrogate-assisted identification of influences of network construction on evolving weighted functional networks

NASA Astrophysics Data System (ADS)

Stahn, Kirsten; Lehnertz, Klaus

2017-12-01

We aim at identifying factors that may affect the characteristics of evolving weighted networks derived from empirical observations. To this end, we employ various chains of analysis that are often used in field studies for a data-driven derivation and characterization of such networks. As an example, we consider fully connected, weighted functional brain networks before, during, and after epileptic seizures that we derive from multichannel electroencephalographic data recorded from epilepsy patients. For these evolving networks, we estimate clustering coefficient and average shortest path length in a time-resolved manner. Lastly, we make use of surrogate concepts that we apply at various levels of the chain of analysis to assess to what extent network characteristics are dominated by properties of the electroencephalographic recordings and/or the evolving weighted networks, which may be accessible more easily. We observe that characteristics are differently affected by the unavoidable referencing of the electroencephalographic recording, by the time-series-analysis technique used to derive the properties of network links, and whether or not networks were normalized. Importantly, for the majority of analysis settings, we observe temporal evolutions of network characteristics to merely reflect the temporal evolutions of mean interaction strengths. Such a property of the data may be accessible more easily, which would render the weighted network approach—as used here—as an overly complicated description of simple aspects of the data.

Quantification of free fatty acids in human stratum corneum using tandem mass spectrometry and surrogate analyte approach.

PubMed

Dapic, Irena; Kobetic, Renata; Brkljacic, Lidija; Kezic, Sanja; Jakasa, Ivone

2018-02-01

The free fatty acids (FFAs) are one of the major components of the lipids in the stratum corneum (SC), the uppermost layer of the skin. Relative composition of FFAs has been proposed as a biomarker of the skin barrier status in patients with atopic dermatitis (AD). Here, we developed an LC-ESI-MS/MS method for simultaneous quantification of a range of FFAs with long and very long chain length in the SC collected by adhesive tape (D-Squame). The method, based on derivatization with 2-bromo-1-methylpyridinium iodide and 3-carbinol-1-methylpyridinium iodide, allowed highly sensitive detection and quantification of FFAs using multiple reaction monitoring. For the quantification, we applied a surrogate analyte approach and internal standardization using isotope labeled derivatives of FFAs. Adhesive tapes showed the presence of several FFAs, which are also present in the SC, a problem encountered in previous studies. Therefore, the levels of FFAs in the SC were corrected using C12:0, which was present on the adhesive tape, but not detected in the SC. The method was applied to SC samples from patients with atopic dermatitis and healthy subjects. Quantification using multiple reaction monitoring allowed sufficient sensitivity to analyze FFAs of chain lengths C16-C28 in the SC collected on only one tape strip. Copyright © 2017 John Wiley & Sons, Ltd.

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

PubMed Central

Wünsch, Matthias; Schröder, David; Fröhr, Tanja; Teichmann, Lisa; Hedwig, Sebastian; Janson, Nils; Belu, Clara; Simon, Jasmin; Heidemeyer, Shari; Holtkamp, Philipp; Rudlof, Jens; Klemme, Lennard; Hinzmann, Alessa; Neumann, Beate; Stammler, Hans-Georg

2017-01-01

The amide moiety of peptides can be replaced for example by a triazole moiety, which is considered to be bioisosteric. Therefore, the carbonyl moiety of an amino acid has to be replaced by an alkyne in order to provide a precursor of such peptidomimetics. As most amino acids have a chiral center at Cα, such amide bond surrogates need a chiral moiety. Here the asymmetric synthesis of a set of 24 N-sulfinyl propargylamines is presented. The condensation of various aldehydes with Ellman’s chiral sulfinamide provides chiral N-sulfinylimines, which were reacted with (trimethylsilyl)ethynyllithium to afford diastereomerically pure N-sulfinyl propargylamines. Diverse functional groups present in the propargylic position resemble the side chain present at the Cα of amino acids. Whereas propargylamines with (cyclo)alkyl substituents can be prepared in a direct manner, residues with polar functional groups require suitable protective groups. The presence of particular functional groups in the side chain in some cases leads to remarkable side reactions of the alkyne moiety. Thus, electron-withdrawing substituents in the Cα-position facilitate a base induced rearrangement to α,β-unsaturated imines, while azide-substituted propargylamines form triazoles under surprisingly mild conditions. A panel of propargylamines bearing fluoro or chloro substituents, polar functional groups, or basic and acidic functional groups is accessible for the use as precursors of peptidomimetics. PMID:29234470

Low-rank separated representation surrogates of high-dimensional stochastic functions: Application in Bayesian inference

NASA Astrophysics Data System (ADS)

Validi, AbdoulAhad

2014-03-01

This study introduces a non-intrusive approach in the context of low-rank separated representation to construct a surrogate of high-dimensional stochastic functions, e.g., PDEs/ODEs, in order to decrease the computational cost of Markov Chain Monte Carlo simulations in Bayesian inference. The surrogate model is constructed via a regularized alternative least-square regression with Tikhonov regularization using a roughening matrix computing the gradient of the solution, in conjunction with a perturbation-based error indicator to detect optimal model complexities. The model approximates a vector of a continuous solution at discrete values of a physical variable. The required number of random realizations to achieve a successful approximation linearly depends on the function dimensionality. The computational cost of the model construction is quadratic in the number of random inputs, which potentially tackles the curse of dimensionality in high-dimensional stochastic functions. Furthermore, this vector-valued separated representation-based model, in comparison to the available scalar-valued case, leads to a significant reduction in the cost of approximation by an order of magnitude equal to the vector size. The performance of the method is studied through its application to three numerical examples including a 41-dimensional elliptic PDE and a 21-dimensional cavity flow.

Assessment of yellowtail kingfish (Seriola lalandi) as a surrogate host for the production of southern bluefin tuna (Thunnus maccoyii) seed via spermatogonial germ cell transplantation.

PubMed

Bar, Ido; Smith, Andre; Bubner, Erin; Yoshizaki, Goro; Takeuchi, Yutaka; Yazawa, Ryosuke; Chen, Ben Nan; Cummins, Scott; Elizur, Abigail

2016-10-01

Germ cell transplantation is an innovative technology for the production of interspecies surrogates, capable of facilitating easier and more economical management of large-bodied broodstock, such as the bluefin tuna. The present study explored the suitability of yellowtail kingfish (Seriola lalandi) as a surrogate host for transplanted southern bluefin tuna (Thunnus maccoyii) spermatogonial cells to produce tuna donor-derived gametes upon sexual maturity. Germ cell populations in testes of donor T. maccoyii males were described using basic histology and the molecular markers vasa and dead-end genes. The peripheral area of the testis was found to contain the highest proportions of dead-end-expressing transplantable Type A spermatogonia. T. maccoyii Type A spermatogonia-enriched preparations were transplanted into the coelomic cavity of 6-10-day-old post-hatch S. lalandi larvae. Fluorescence microscopy and polymerase chain reaction analysis detected the presence of tuna cells in the gonads of the transplanted kingfish fingerlings at 18, 28, 39 and 75 days after transplantation, indicating that the transplanted cells migrated to the genital ridge and had colonised the developing gonad. T. maccoyii germ cell-derived DNA or RNA was not detected at later stages, suggesting that the donor cells were not maintained in the hosts' gonads.

Near Real-Time Probabilistic Damage Diagnosis Using Surrogate Modeling and High Performance Computing

NASA Technical Reports Server (NTRS)

Warner, James E.; Zubair, Mohammad; Ranjan, Desh

2017-01-01

This work investigates novel approaches to probabilistic damage diagnosis that utilize surrogate modeling and high performance computing (HPC) to achieve substantial computational speedup. Motivated by Digital Twin, a structural health management (SHM) paradigm that integrates vehicle-specific characteristics with continual in-situ damage diagnosis and prognosis, the methods studied herein yield near real-time damage assessments that could enable monitoring of a vehicle's health while it is operating (i.e. online SHM). High-fidelity modeling and uncertainty quantification (UQ), both critical to Digital Twin, are incorporated using finite element method simulations and Bayesian inference, respectively. The crux of the proposed Bayesian diagnosis methods, however, is the reformulation of the numerical sampling algorithms (e.g. Markov chain Monte Carlo) used to generate the resulting probabilistic damage estimates. To this end, three distinct methods are demonstrated for rapid sampling that utilize surrogate modeling and exploit various degrees of parallelism for leveraging HPC. The accuracy and computational efficiency of the methods are compared on the problem of strain-based crack identification in thin plates. While each approach has inherent problem-specific strengths and weaknesses, all approaches are shown to provide accurate probabilistic damage diagnoses and several orders of magnitude computational speedup relative to a baseline Bayesian diagnosis implementation.

Myosin content of individual human muscle fibers isolated by laser capture microdissection.

PubMed

Stuart, Charles A; Stone, William L; Howell, Mary E A; Brannon, Marianne F; Hall, H Kenton; Gibson, Andrew L; Stone, Michael H

2016-03-01

Muscle fiber composition correlates with insulin resistance, and exercise training can increase slow-twitch (type I) fibers and, thereby, mitigate diabetes risk. Human skeletal muscle is made up of three distinct fiber types, but muscle contains many more isoforms of myosin heavy and light chains, which are coded by 15 and 11 different genes, respectively. Laser capture microdissection techniques allow assessment of mRNA and protein content in individual fibers. We found that specific human fiber types contain different mixtures of myosin heavy and light chains. Fast-twitch (type IIx) fibers consistently contained myosin heavy chains 1, 2, and 4 and myosin light chain 1. Type I fibers always contained myosin heavy chains 6 and 7 (MYH6 and MYH7) and myosin light chain 3 (MYL3), whereas MYH6, MYH7, and MYL3 were nearly absent from type IIx fibers. In contrast to cardiomyocytes, where MYH6 (also known as α-myosin heavy chain) is seen solely in fast-twitch cells, only slow-twitch fibers of skeletal muscle contained MYH6. Classical fast myosin heavy chains (MHC1, MHC2, and MHC4) were present in variable proportions in all fiber types, but significant MYH6 and MYH7 expression indicated slow-twitch phenotype, and the absence of these two isoforms determined a fast-twitch phenotype. The mixed myosin heavy and light chain content of type IIa fibers was consistent with its role as a transition between fast and slow phenotypes. These new observations suggest that the presence or absence of MYH6 and MYH7 proteins dictates the slow- or fast-twitch phenotype in skeletal muscle. Copyright © 2016 the American Physiological Society.

Myosin content of individual human muscle fibers isolated by laser capture microdissection

PubMed Central

Stone, William L.; Howell, Mary E. A.; Brannon, Marianne F.; Hall, H. Kenton; Gibson, Andrew L.; Stone, Michael H.

2015-01-01

Muscle fiber composition correlates with insulin resistance, and exercise training can increase slow-twitch (type I) fibers and, thereby, mitigate diabetes risk. Human skeletal muscle is made up of three distinct fiber types, but muscle contains many more isoforms of myosin heavy and light chains, which are coded by 15 and 11 different genes, respectively. Laser capture microdissection techniques allow assessment of mRNA and protein content in individual fibers. We found that specific human fiber types contain different mixtures of myosin heavy and light chains. Fast-twitch (type IIx) fibers consistently contained myosin heavy chains 1, 2, and 4 and myosin light chain 1. Type I fibers always contained myosin heavy chains 6 and 7 (MYH6 and MYH7) and myosin light chain 3 (MYL3), whereas MYH6, MYH7, and MYL3 were nearly absent from type IIx fibers. In contrast to cardiomyocytes, where MYH6 (also known as α-myosin heavy chain) is seen solely in fast-twitch cells, only slow-twitch fibers of skeletal muscle contained MYH6. Classical fast myosin heavy chains (MHC1, MHC2, and MHC4) were present in variable proportions in all fiber types, but significant MYH6 and MYH7 expression indicated slow-twitch phenotype, and the absence of these two isoforms determined a fast-twitch phenotype. The mixed myosin heavy and light chain content of type IIa fibers was consistent with its role as a transition between fast and slow phenotypes. These new observations suggest that the presence or absence of MYH6 and MYH7 proteins dictates the slow- or fast-twitch phenotype in skeletal muscle. PMID:26676053

Light, nutrients, and food-chain length constrain planktonic energy transfer efficiency across multiple trophic levels

PubMed Central

Dickman, Elizabeth M.; Newell, Jennifer M.; González, María J.; Vanni, Michael J.

2008-01-01

The efficiency of energy transfer through food chains [food chain efficiency (FCE)] is an important ecosystem function. It has been hypothesized that FCE across multiple trophic levels is constrained by the efficiency at which herbivores use plant energy, which depends on plant nutritional quality. Furthermore, the number of trophic levels may also constrain FCE, because herbivores are less efficient in using plant production when they are constrained by carnivores. These hypotheses have not been tested experimentally in food chains with 3 or more trophic levels. In a field experiment manipulating light, nutrients, and food-chain length, we show that FCE is constrained by algal food quality and food-chain length. FCE across 3 trophic levels (phytoplankton to carnivorous fish) was highest under low light and high nutrients, where algal quality was best as indicated by taxonomic composition and nutrient stoichiometry. In 3-level systems, FCE was constrained by the efficiency at which both herbivores and carnivores converted food into production; a strong nutrient effect on carnivore efficiency suggests a carryover effect of algal quality across 3 trophic levels. Energy transfer efficiency from algae to herbivores was also higher in 2-level systems (without carnivores) than in 3-level systems. Our results support the hypothesis that FCE is strongly constrained by light, nutrients, and food-chain length and suggest that carryover effects across multiple trophic levels are important. Because many environmental perturbations affect light, nutrients, and food-chain length, and many ecological services are mediated by FCE, it will be important to apply these findings to various ecosystem types. PMID:19011082

In-stem labelling allows visualization of DNA strand displacements by distinct fluorescent colour change.

PubMed

Barrois, Sebastian; Wagenknecht, Hans-Achim

2013-05-21

The combination of thiazole orange (TO) and thiazole red (TR) as an internal pair of fluorescent DNA base surrogates ("DNA traffic lights") allows us to follow at least two consecutive DNA strand displacements in real time through a distinct fluorescence colour change from green to red and vice versa.

CT contrast predicts pancreatic cancer treatment response to verteporfin-based photodynamic therapy

NASA Astrophysics Data System (ADS)

Jermyn, Michael; Davis, Scott C.; Dehghani, Hamid; Huggett, Matthew T.; Hasan, Tayyaba; Pereira, Stephen P.; Bown, Stephen G.; Pogue, Brian W.

2014-04-01

The goal of this study was to determine dominant factors affecting treatment response in pancreatic cancer photodynamic therapy (PDT), based on clinically available information in the VERTPAC-01 trial. This trial investigated the safety and efficacy of verteporfin PDT in 15 patients with locally advanced pancreatic adenocarcinoma. CT scans before and after contrast enhancement from the 15 patients in the VERTPAC-01 trial were used to determine venous-phase blood contrast enhancement and this was correlated with necrotic volume determined from post-treatment CT scans, along with estimation of optical absorption in the pancreas for use in light modeling of the PDT treatment. Energy threshold contours yielded estimates for necrotic volume based on this light modeling. Both contrast-derived venous blood content and necrotic volume from light modeling yielded strong correlations with observed necrotic volume (R2 = 0.85 and 0.91, respectively). These correlations were much stronger than those obtained by correlating energy delivered versus necrotic volume in the VERTPAC-01 study and in retrospective analysis from a prior clinical study. This demonstrates that contrast CT can provide key surrogate dosimetry information to assess treatment response. It also implies that light attenuation is likely the dominant factor in the VERTPAC treatment response, as opposed to other factors such as drug distribution. This study is the first to show that contrast CT provides needed surrogate dosimetry information to predict treatment response in a manner which uses standard-of-care clinical images, rather than invasive dosimetry methods.

Low-Power Light Guiding and Localization in Optoplasmonic Chains Obtained by Directed Self-Assembly

PubMed Central

Ahn, Wonmi; Zhao, Xin; Hong, Yan; Reinhard, Björn M.

2016-01-01

Optoplasmonic structures contain plasmonic components embedded in a defined photonic environment to create synergistic interactions between photonic and plasmonic components. Here, we show that chains of optical microspheres containing gold nanoparticles in their evanescent field combine the light guiding properties of a microsphere chain with the light localizing properties of a plasmonic nanoantenna. We implement these materials through template guided self-assembly and investigate their fundamental electromagnetic working principles through combination of electromagnetic simulations and experimental characterization. We demonstrate that optoplasmonic chains implemented by directed self-assembly achieve a significant reduction in guiding losses when compared with conventional plasmonic waveguides and, at the same time, retain the light localizing properties of plasmonic antennas at pre-defined locations. The results reinforce the potential of optoplasmonic structures for realizing low-loss optical interconnects with high bandwidth. PMID:26931149

Minimum requirements for inhibition of smooth-muscle myosin light-chain kinase by synthetic peptides.

PubMed Central

Hunt, J T; Floyd, D M; Lee, V G; Little, D K; Moreland, S

1989-01-01

Although the amino acid residues that are important for peptide substrates of myosin light-chain kinase have been reported, those that are important for peptide inhibitors of this enzyme have not previously been investigated. Synthetic peptides based on the sequence Lys11-Lys12-Arg13-Ala-Ala-Arg16-Ala-Thr-Ser19 -Asn-Val21-Phe22-Ala of the chicken gizzard myosin light chain were tested as inhibitors of pig carotid-artery myosin light-chain kinase. The basic amino acid residues of the known myosin light-chain kinase inhibitor Lys-Lys-Arg-Ala-Ala-Arg-Ala-Thr-Ser-NH2 (IC50 = 14 microM) [Pearson, Misconi & Kemp (1986) J. Biol. Chem. 261, 25-27] were shown to be the important residues that contribute to inhibitor potency, as evidence by the finding that the hexapeptide Lys-Lys-Arg-Ala-Ala-Arg-NH2 had an IC50 value of 22 microM. This indicates that binding of the phosphorylatable serine residue to myosin light-chain kinase, which is of obvious importance for a substrate, does not enhance the potency of an inhibitor. With the aim of preparing more potent inhibitors, peptides Lys-Lys-Arg-Ala-Ala-Arg-Ala-Ala-Xaa-NH2 were prepared with a variety of amino acids substituted for the phosphorylatable serine residue. None of these peptides was a more potent inhibitor than the serine peptide. PMID:2920029

Estimation of polyclonal IgG4 hybrids in normal human serum.

PubMed

Young, Elizabeth; Lock, Emma; Ward, Douglas G; Cook, Alexander; Harding, Stephen; Wallis, Gregg L F

2014-07-01

The in vivo or in vitro formation of IgG4 hybrid molecules, wherein the immunoglobulins have exchanged half molecules, has previously been reported under experimental conditions. Here we estimate the incidence of polyclonal IgG4 hybrids in normal human serum and comment on the existence of IgG4 molecules with different immunoglobulin light chains. Polyclonal IgG4 was purified from pooled or individual donor human sera and sequentially fractionated using light-chain affinity and size exclusion chromatography. Fractions were analysed by SDS-PAGE, immunoblotting, ELISA, immunodiffusion and matrix-assisted laser-desorption mass spectrometry. Polyclonal IgG4 purified from normal serum contained IgG4κ, IgG4λ and IgG4κ/λ molecules. Size exclusion chromatography showed that IgG4 was principally present in monomeric form (150 000 MW). SDS-PAGE, immunoblotting and ELISA showed the purity of the three IgG4 samples. Immunodiffusion, light-chain sandwich ELISA and mass spectrometry demonstrated that both κ and λ light chains were present on only the IgG4κ/λ molecules. The amounts of IgG4κ/λ hybrid molecules ranged from 21 to 33% from the five sera analysed. Based on the molecular weight these molecules were formed of two IgG4 heavy chains plus one κ and one λ light chain. Polyclonal IgG (IgG4-depleted) was similarly fractionated according to light-chain specificity. No evidence of hybrid IgG κ/λ antibodies was observed. These results indicate that hybrid IgG4κ/λ antibodies compose a substantial portion of IgG4 from normal human serum. © 2014 John Wiley & Sons Ltd.

A molecular model for self-assembly of amyloid fibrils: Immunoglobulin light chains

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

Stevens, F.J.; Myatt, E.A.; Westholm, F.A.

1995-08-29

The formation and pathological deposition of amyloid fibrils are defining features of many acquired and inherited disorders, including primary or light-chain-associated amyloidosis, Alzheimer`s disease, and adult-onset diabetes. No pharmacological methods exist to block this process or to effect the removal of fibrils from tissue, and thus, little can be done to prevent organ failure and ultimate death that result from deposition of amyloid. Knowledge of the pathogenesis, treatment, or prevention of these presently incurable diseases is limited due to the relative paucity of information regarding the biophysical basis of amyloid formation. Antibody light chains of different amino acid sequence showmore » differential amyloid-forming tendencies and, as such, can provide insight into the structural organization of amyloid fibrils as well as into basic mechanisms of protein self-assembly. We have compared primary structures of 180 human monoclonal light chains and have identified particular residues and positions within the variable domain that differentiate amyloid-from nonamyloid-associated proteins. We propose a molecular model that accounts for amyloid formation by antibody light chains and might also have implications for other forms of amyloidosis. 24 refs., 2 figs., 1 tab.« less

Immunoglobulin light chain allelic inclusion in systemic lupus erythematosus.

PubMed

Fraser, Louise D; Zhao, Yuan; Lutalo, Pamela M K; D'Cruz, David P; Cason, John; Silva, Joselli S; Dunn-Walters, Deborah K; Nayar, Saba; Cope, Andrew P; Spencer, Jo

2015-08-01

The principles of allelic exclusion state that each B cell expresses a single light and heavy chain pair. Here, we show that B cells with both kappa and lambda light chains (Igκ and Igλ) are enriched in some patients with the systemic autoimmune disease systemic lupus erythematosus (SLE), but not in the systemic autoimmune disease control granulomatosis with polyangiitis. Detection of dual Igκ and Igλ expression by flow cytometry could not be abolished by acid washing or by DNAse treatment to remove any bound polyclonal antibody or complexes, and was retained after two days in culture. Both surface and intracytoplasmic dual light chain expression was evident by flow cytometry and confocal microscopy. We observed reduced frequency of rearrangements of the kappa-deleting element (KDE) in SLE and an inverse correlation between the frequency of KDE rearrangement and the frequency of dual light chain expressing B cells. We propose that dual expression of Igκ and Igλ by a single B cell may occur in some patients with SLE when this may be a consequence of reduced activity of the KDE. © 2015 The Authors. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Developing the (d,p γ) reaction as a surrogate for (n, γ) in inverse kinematics

NASA Astrophysics Data System (ADS)

Lepailleur, Alexandre; Baugher, Travis; Cizewski, Jolie; Ratkiewicz, Andrew; Walter, David; Pain, Steven; Smith, Karl; Garland, Heather; Goddess Collaboration

2016-09-01

The r-process that proceeds via (n, γ) reactions on neutron-rich nuclei is responsible for the synthesis of about half of the elements heavier than iron. Because (n, γ) measurements on short-lived isotopes are not possible, the (d,p γ) reaction is being investigated as a surrogate for (n, γ). Of particular importance is validating a surrogate in inverse kinematics. Therefore, the 95Mo(d,p γ) reaction was measured in inverse kinematics with stable beams from ATLAS and CD2 targets. Reaction protons were measured in coincidence with gamma rays with GODDESS - Gammasphere ORRUBA: Dual Detectors for Experimental Structure Studies. The Oak Ridge Rutgers University Barrel Array (ORRUBA) of position-sensitive silicon strip detectors was augmented with annular arrays of segmented strip detectors at backward and forward angles, resulting in a high-angular coverage for light ejectiles. Preliminary results from the 95Mo(d,p γ) study will be presented. This work was supported in part by the U.S. Department of Energy and National Science Foundation.

[Construction of dengue virus-specific full-length fully human antibody libraries by mammalian display technology].

PubMed

Wen, Yangming; Lan, Kaijian; Wang, Junjie; Yu, Jingyi; Qu, Yarong; Zhao, Wei; Zhang, Fuchun; Tan, Wanlong; Cao, Hong; Zhou, Chen

2013-06-01

To construct dengue virus-specific full-length fully human antibody libraries using mammalian cell surface display technique. Total RNA was extracted from peripheral blood mononuclear cells (PBMCs) from convalescent patients with dengue fever. The reservoirs of the light chain and heavy chain variable regions (LCκ and VH) of the antibody genes were amplified by RT-PCR and inserted into the vector pDGB-HC-TM separately to construct the light chain and heavy chain libraries. The library DNAs were transfected into CHO cells and the expression of full-length fully human antibodies on the surface of CHO cells was analyzed by flow cytometry. Using 1.2 µg of the total RNA isolated from the PBMCs as the template, the LCκ and VH were amplified and the full-length fully human antibody mammalian display libraries were constructed. The kappa light chain gene library had a size of 1.45×10(4) and the heavy chain gene library had a size of 1.8×10(5). Sequence analysis showed that 8 out of the 10 light chain clones and 7 out of the 10 heavy chain clones randomly picked up from the constructed libraries contained correct open reading frames. FACS analysis demonstrated that all the 15 clones with correct open reading frames expressed full-length antibodies, which could be detected on CHO cell surfaces. After co-transfection of the heavy chain and light chain gene libraries into CHO cells, the expression of full-length antibodies on CHO cell surfaces could be detected by FACS analysis with an expressible diversity of the antibody library reaching 1.46×10(9) [(1.45×10(4)×80%)×(1.8×10(5)×70%)]. Using 1.2 µg of total RNA as template, the LCκ and VH full-length fully human antibody libraries against dengue virus have been successfully constructed with an expressible diversity of 10(9).

Isotype analysis of the anti-CENP-B anticentromere autoantibody: evidence for restricted clonality.

PubMed

Eisenberg, R A; Earnshaw, W C; Bordwell, B J; Craven, S Y; Cheek, R; Rothfield, N F

1989-10-01

Utilizing the centromere B fusion protein (CENP-B) and specific, matched monoclonal antiisotype reagents in an enzyme-linked immunosorbent assay, we found that anti-CENP-B autoantibodies were skewed to the IgG1 isotype. The overall kappa:lambda light chain ratio was 2:1, although several individual sera showed a strong predominance of one of the light chains. Isoelectric focusing of light chain-skewed sera showed polyclonal patterns. Our findings are consistent with the anti-CENP-B autoantibody response being a chronic, antigen-driven response.

Validation of serum free light chain reference ranges in primary care.

PubMed

Galvani, Luca; Flanagan, Jane; Sargazi, Mansour; Neithercut, William D

2016-05-01

The demand for measurement of serum immunoglobulin free kappa (κ) and lambda (λ) light chains has increased. The κ:λ ratio is used to assist in diagnosis/monitoring of plasma cell disorders. The binding site reference range for serum-free light chain κ:λ ratios of 0.26-1.65 was derived from healthy volunteers. Subsequently, a reference range of 0.37-3.1 for patients with chronic kidney disease has been proposed. Elevated free light chain concentrations and borderline raised free light chain ratios also may be found in polyclonal gammopathies and with other non-renal illnesses. This assessment was conducted to validate the established free light chain reference ranges in individuals from primary care. A total of 130 samples were identified from routine blood samples collected in primary care for routine biochemistry testing and estimated glomerular filtration rate calculation. The median and range of κ:λ ratios found in each estimated glomerular filtration rate group used for chronic kidney disease classification were higher than previously described. This was the case for individuals with normal or essentially normal renal function with estimated glomerular filtration rates>90, (0.58-1.76) and estimated glomerular filtration rate of 60-90 mL/min/1.73 m(2), (0.71-1.93). Individuals with estimated glomerular filtration rate 15-30, (0.72-4.50) and estimated glomerular filtration rate <15 ml/min/1.73 m(2) (0.71-4.95) also had higher values when compared to the current renal reference range of 0.37-3.10. Elevation of free light chain-κ:λ ratios may occur in the absence of a reduced renal function shown by a normal estimated glomerular filtration rate and in the presence of reduced renal function by estimated glomerular filtration rate when comparing results with the established reference ranges. Explanations include choice of analytical systems or the presence of other concurrent non-plasma cell illness. © The Author(s) 2016.

Productive Recognition of Factor IX by Factor XIa Exosites Requires Disulfide Linkage between Heavy and Light Chains of Factor XIa*

PubMed Central

Marcinkiewicz, Mariola M.; Sinha, Dipali; Walsh, Peter N.

2012-01-01

In the intrinsic pathway of blood coagulation factor XIa (FXIa) activates factor IX (FIX) by cleaving the zymogen at Arg145-Ala146 and Arg180-Val181 bonds releasing an 11-kDa activation peptide. FXIa and its isolated light chain (FXIa-LC) cleave S-2366 at comparable rates, but FXIa-LC is a very poor activator of FIX, possibly because FIX undergoes allosteric modification on binding to an exosite on the heavy chain of FXIa (FXIa-HC) required for optimal cleavage rates of the two scissile bonds of FIX. However preincubation of FIX with a saturating concentration of isolated FXIa-HC did not result in any potentiation in the rate of FIX cleavage by FXIa-LC. Furthermore, if FIX binding via the heavy chain exosite of FXIa determines the affinity of the enzyme-substrate interaction, then the isolated FXIa-HC should inhibit the rate of FIX activation by depleting the substrate. However, whereas FXIa/S557A inhibited FIX activation of by FXIa, FXIa-HC did not. Therefore, we examined FIX binding to FXIa/S557A, FXIa-HC, FXIa-LC, FXIa/C362S/C482S, and FXIa/S557A/C362S/C482S. The heavy and light chains are disulfide-linked in FXIa/S557A but not in FXIa/C362S/C482S and FXIa/S557A/C362S/C482S. In an ELISA assay only FXI/S557A ligated FIX with high affinity. Partial reduction of FXIa/S557A to produce heavy and light chains resulted in decreased FIX binding, and this function was regained upon reformation of the disulfide linkage between the heavy and the light chains. We therefore conclude that substrate recognition by the FXIa exosite(s) requires disulfide-linked heavy and light chains. PMID:22207756

Surrogate mother – praiseworthy or stigmatized: a qualitative study on perceptions of surrogacy in Assam, India

PubMed Central

Arvidsson, Anna; Vauquline, Polly; Johnsdotter, Sara; Essén, Birgitta

2017-01-01

ABSTRACT Background: Surrogacy is a reproductive practice that has been strongly marketed in India as a solution for childless couples. As a result, the number of surrogacy clinics is increasing. Meanwhile, a global discourse on surrogacy, originating from a Western perspective, has characterized surrogacy as being exploitative of women in low-income settings, where poverty drives them to become surrogate mothers. Objective: This study explored perspectives on surrogacy from men and women in Assam, an Indian state known to be a low-income setting. Surrogacy arrangements in Assam are still uncommon. It can be expected that the dominant global discourses on surrogacy will be unfamiliar to the general population, and the objective was also to position the results within the divergent global discourses of surrogacy. Methods: In order to explore local views on surrogacy, we conducted individual interviews and focus group discussions with people from various socioeconomic groups in Assam. Results: Our findings reveal that people in Assam perceive surrogacy as a good option for a childless couple, as it would result in a child who is a ‘blood’ relation – something highly desirable for sociocultural reasons. However, the part played by the surrogate mother complicates local views on surrogacy. Most people consider payment to the surrogate mother contrary to societal norms. A surrogate mother is also often judged in a moral light, either as a ‘bad mother’ for selling her child, or as a ‘noble woman’ who has helped a childless couple and deserves payment for her services. Conclusions: In order to decrease the stigmatization of women, a regulatory policy is needed that will take into account the complex understandings of surrogacy and perceptions of surrogate mothers in Indian society. In policy, the possible effect of the dominant exploitation discourse needs to be modulated by local understandings of this reproduction method. PMID:28604252

Beaded-chain collars: A new method to radiotag kangaroo rats for short-term studies

USGS Publications Warehouse

Harker, M.B.; Rathbun, G.B.; Langtimm, C.A.

1999-01-01

To study burrow use by small mammals, we needed to develop a simple, non-invasive radiotag for the endangered giant kangaroo rat (Dipodomys ingens). We designed and tested a radiocollar made of beaded-chain on 4 captive Heermann's kangaroo rats (D. heermanii). Attachment of the collar required no anesthesia, the collar was easily fitted in 1-2 minutes, and it caused minimal stress to the animals. Once the collar design and attachment technique were perfected on the surrogate animals, we fitted radiocollars on 48 giant kangaroo rats for about 15 days. Upon recapture, 12 animals showed some minor fur or skin abrasion on the neck. Overall, the attachment performed as expected and proved to be a reliable method to radiotrack kangaroo rats during our short-term field study.

Loss of tubular creatinine secretion as the only sign of tubular proximal cell dysfunction in light chain proximal tubulopathy: A case report.

PubMed

Stehlé, Thomas; Vignon, Marguerite; Flamant, Martin; Figueres, Marie-Lucile; Rabant, Marion; Rodenas, Anita; Noël, Laure-Hélène; Arnulf, Bertrand; Vidal-Petiot, Emmanuelle

2016-06-01

Light chain proximal tubulopathy (LCPT) is a rare disease, characterized by cytoplasmic inclusions of light chain (usually kappa) immunoglobulins. Clinical presentation is usually a Fanconi syndrome. The proximal tubular dysfunction can be incomplete, and exceptional cases of LCPT without any tubular dysfunction have even been described. Here, we report a case of LCPT in which the only sign of proximal tubulopathy is the absence of secretion of creatinine, as assessed by the simultaneous measurement of renal clearance of creatinine and CrEDTA. The loss of tubular creatinine secretion as a sign of tubular proximal cell dysfunction ought to be identified in patients with light chain proximal tubulopathy as it leads to a clinically relevant underestimation of GFR by the creatinine-derived equations. The prevalence and prognostic significance of this particular proximal tubular damage in LCPT remain to be determined.

Low-power light guiding and localization in optoplasmonic chains obtained by directed self-assembly

DOE PAGES

Ahn, Wonmi; Zhao, Xin; Hong, Yan; ...

2016-03-02

Here, optoplasmonic structures contain plasmonic components embedded in a defined photonic environment to create synergistic interactions between photonic and plasmonic components. Here, we show that chains of optical microspheres containing gold nanoparticles in their evanescent field combine the light guiding properties of a microsphere chain with the light localizing properties of a plasmonic nanoantenna. We implement these materials through template guided self-assembly and investigate their fundamental electromagnetic working principles through combination of electromagnetic simulations and experimental characterization. We demonstrate that optoplasmonic chains implemented by directed self-assembly achieve a significant reduction in guiding losses when compared with conventional plasmonic waveguides and,more » at the same time, retain the light localizing properties of plasmonic antennas at pre-defined locations. The results reinforce the potential of optoplasmonic structures for realizing low-loss optical interconnects with high bandwidth.« less

Antigen Binding and Site-Directed Labeling of Biosilica-Immobilized Fusion Proteins Expressed in Diatoms

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

Ford, Nicole R.; Hecht, Karen A.; Hu, Dehong

2016-01-08

The diatom Thalassiosira pseudonana was genetically modified to express biosilica-targeted fusion proteins incorporating a tetracysteine tag for site-directed labeling with biarsenical affinity probes and either EGFP or single chain antibody to test colocalization of probes with the EGFP-tagged recombinant protein or binding of biosilica-immobilized antibodies to large and small molecule antigens, respectively. Site-directed labeling with the biarsenical probes demonstrated colocalization with EGFP-encoded proteins in nascent and mature biosilica, supporting their use in studying biosilica maturation. Isolated biosilica transformed with a single chain antibody against either the Bacillus anthracis surface layer protein EA1 or small molecule explosive trinitrotoluene (TNT) effectively boundmore » the respective antigens. A marked increase in fluorescence lifetime of the TNT surrogate Alexa Fluor 555-trinitrobenzene reflected the high binding specificity of the transformed isolated biosilica. These results demonstrated the potential use of biosilica-immobilized single chain antibodies as binders for large and small molecule antigens in sensing and therapeutics.« less

Phenotyping polyclonal kappa and lambda light chain molecular mass distributions in patient serum using mass spectrometry.

PubMed

Barnidge, David R; Dasari, Surendra; Ramirez-Alvarado, Marina; Fontan, Adrian; Willrich, Maria A V; Tschumper, Renee C; Jelinek, Diane F; Snyder, Melissa R; Dispenzieri, Angela; Katzmann, Jerry A; Murray, David L

2014-11-07

We previously described a microLC-ESI-Q-TOF MS method for identifying monoclonal immunoglobulins in serum and then tracking them over time using their accurate molecular mass. Here we demonstrate how the same methodology can be used to identify and characterize polyclonal immunoglobulins in serum. We establish that two molecular mass distributions observed by microLC-ESI-Q-TOF MS are from polyclonal kappa and lambda light chains using a combination of theoretical molecular masses from gene sequence data and the analysis of commercially available purified polyclonal IgG kappa and IgG lambda from normal human serum. A linear regression comparison of kappa/lambda ratios for 74 serum samples (25 hypergammaglobulinemia, 24 hypogammaglobulinemia, 25 normal) determined by microflowLC-ESI-Q-TOF MS and immunonephelometry had a slope of 1.37 and a correlation coefficient of 0.639. In addition to providing kappa/lambda ratios, the same microLC-ESI-Q-TOF MS analysis can determine the molecular mass for oligoclonal light chains observed above the polyclonal background in patient samples. In 2 patients with immune disorders and hypergammaglobulinemia, we observed a skewed polyclonal molecular mass distribution which translated into biased kappa/lambda ratios. Mass spectrometry provides a rapid and simple way to combine the polyclonal kappa/lambda light chain abundance ratios with the identification of dominant monoclonal as well as oligoclonal light chain immunoglobulins. We anticipate that this approach to evaluating immunoglobulin light chains will lead to improved understanding of immune deficiencies, autoimmune diseases, and antibody responses.

Detection of the value of consecutive serum total light chain (sTLC) in patients diagnosed with diffuse large B cell lymphoma.

PubMed

Zhai, Linzhu; Zhao, Yuanyuan; Peng, Songguo; Zhu, Ke; Yu, Rongjian; Chen, Hailong; Lin, Tongyu; Lin, Lizhu

2016-12-01

There are limited data on serum total light chain (sTLC) in lymphoma and its relative role on the outcome of diffuse large B cell lymphoma (DLBCL) patients. Blood samples from 46 cases newly diagnosed with DLBCL were collected consecutively during chemotherapy to detect sTLC, IgG, IgA, and IgM levels. Clinical data and survival outcomes were analyzed according to the results of sTLC measurements. In summary, 22 patients (47.8 %) had abnormal k or λ light chain, respectively, and 6 patients (13.0 %) had both abnormal k and λ light chains before chemotherapy. Patients with elevated k light chain more frequently displayed multiple extra-nodal organ involvement (P = 0.01) and had an inferior overall survival (OS) (P = 0.041) and progression-free survival (PFS) (P = 0.044) compared to patients with normal level of k light chain. Furthermore, patients with elevated level of both k and λ also exhibited significant association with shorter OS (P = 0.002) and PFS (P = 0.009). Both elevated k alone and concurrent elevated k and λ had independent adverse effects on PFS (P = 0.031 and P = 0.019, respectively). sTLC level was reduced gradually by treatment in this study and reached the lowest point after the fourth cycle of chemotherapy, which was consistent with the disease behavior during chemotherapy. Considering the small sample size of this study, these results should be confirmed in a larger prospective study.

False-negative rate, limit of detection and recovery efficiency performance of a validated macrofoam-swab sampling method for low surface concentrations of Bacillus anthracis Sterne and Bacillus atrophaeus spores

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

Piepel, G. F.; Deatherage Kaiser, B. L.; Amidan, B. G.

The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target amounts (2-500 spores) to positive-control plates and test coupons (2 in × 2 in) of four surface materials (glass, stainless steel, vinyl tile, and plastic). Test results from cultured samples were used to evaluate the effects of surrogate, surface concentration, and surface material on recovery efficiency (RE), false negative rate (FNR), and limit of detection. For RE, surrogate and surface material had statistically significant effects, but concentration did not. Mean REs were the lowest formore » vinyl tile (50.8% with BAS and 40.2% with BG) and the highest for glass (92.8% with BAS and 71.4% with BG). FNR values ranged from 0 to 0.833 for BAS and 0 to 0.806 for BG; values increased as concentration decreased in the range tested (0.078 to 19.375 CFU/cm2). Surface material also had a statistically significant effect. A FNR-concentration curve was fit for each combination of surrogate and surface material. For both surrogates, the FNR curves tended to be the lowest for glass and highest for vinyl title. The FNR curves for BG tended to be higher than for BAS at lower concentrations, especially for glass. Results using a modified Rapid Viability-Polymerase Chain Reaction (mRV-PCR) analysis method were also obtained. The mRV-PCR results and comparisons to the culture results will be discussed in a subsequent article.« less

Supervised Remote Robot with Guided Autonomy and Teleoperation (SURROGATE): A Framework for Whole-Body Manipulation

NASA Technical Reports Server (NTRS)

Hebert, Paul; Ma, Jeremy; Borders, James; Aydemir, Alper; Bajracharya, Max; Hudson, Nicolas; Shankar, Krishna; Karumanchi, Sisir; Douillard, Bertrand; Burdick, Joel

2015-01-01

The use of the cognitive capabilties of humans to help guide the autonomy of robotics platforms in what is typically called "supervised-autonomy" is becoming more commonplace in robotics research. The work discussed in this paper presents an approach to a human-in-the-loop mode of robot operation that integrates high level human cognition and commanding with the intelligence and processing power of autonomous systems. Our framework for a "Supervised Remote Robot with Guided Autonomy and Teleoperation" (SURROGATE) is demonstrated on a robotic platform consisting of a pan-tilt perception head, two 7-DOF arms connected by a single 7-DOF torso, mounted on a tracked-wheel base. We present an architecture that allows high-level supervisory commands and intents to be specified by a user that are then interpreted by the robotic system to perform whole body manipulation tasks autonomously. We use a concept of "behaviors" to chain together sequences of "actions" for the robot to perform which is then executed real time.

Cysteine Racemization on IgG Heavy and Light Chains

PubMed Central

Zhang, Qingchun; Flynn, Gregory C.

2013-01-01

Under basic pH conditions, the heavy chain 220-light chain 214 (H220-L214) disulfide bond, found in the flexible hinge region of an IgG1, can convert to a thioether. Similar conditions also result in racemization of the H220 cysteine. Here, we report that racemization occurs on both H220 and L214 on an IgG1 with a λ light chain (IgG1λ) but almost entirely on H220 of an IgGl with a κ light chain (IgG1κ) under similar conditions. Likewise, racemization was detected at significant levels on H220 and L214 on endogenous human IgG1λ but only at the H220 position on IgG1κ. Low but measurable levels of d-cysteines were found on IgG2 cysteines in the hinge region, both with monoclonal antibodies incubated under basic pH conditions and on antibodies isolated from human serum. A simplified reaction mechanism involving reversible β-elimination on the cysteine is presented that accounts for both base-catalyzed racemization and thioether formation at the hinge disulfide. PMID:24142697

A traffic signal for heterodimeric amino acid transporters to transfer from the ER to the Golgi.

PubMed

Ganapathy, Vadivel

2009-01-15

Heterodimeric amino acid transporters represent a unique class of transport systems that consist of a light chain that serves as the 'transporter proper' and a heavy chain that is necessary for targeting the complex to the plasma membrane. The currently prevailing paradigm assigns no role for the light chains in the cellular processing of these transporters. In this issue of the Biochemical Journal, Sakamoto et al. provide evidence contrary to this paradigm. Their studies with the rBAT -b(0,+)AT (related to b(0,+) amino acid transporter-b(0,+)-type amino acid transporter) heterodimeric amino acid transporter show that the C-terminus of the light chain b(0,+)AT contains a sequence motif that serves as the traffic signal for the transfer of the heterodimeric complex from the endoplasmic reticulum to the Golgi. This is a novel function for the light chain in addition to its already established role as the subunit responsible for the transport activity. These new findings also seem to be applicable to other heterodimeric amino acid transporters as well.

Light-responsive expansion-contraction of spherical nanoparticle grafted with azopolymers

NASA Astrophysics Data System (ADS)

Fu, Jie; Zhang, Xinghua; Miao, Bing; Yan, Dadong

2017-04-01

Due to the very importance for both fundamental research and technological applications, smart materials with stimuli-responsive properties have been studied intensively. Theoretical investigation contributes to this endeavor through constructing and analyzing a model system which captures main features of the corresponding complex material, wherefrom useful insight can be provided to the trial-and-error experiments. We here report a theoretical study on the smart spherical nanoparticle grafted with light-responsive azobenzene-containing polymers. Utilizing the photoisomerization ability of the azobenzene group, nanoparticles can undergo a light-induced expansion-contraction transition. The wormlike chain based single chain in mean field theory, which has been developed by us recently, is used to investigate this transition in detail. Exploring a large parameter space, our results definitely determine the parameters, including the chain length and effective Kuhn length of grafted chain, nanoparticle radius, grafting density, and position of the azobenzene group along the chain contour, to admit optimum light-responsive behavior of the smart nanoparticle, which provides a guide for experimentalists to design this type of material in a rational manner.

Immunoturbidimetric assay for estimating free light chains of immunoglobulins in urine and serum.

PubMed Central

Tillyer, C R; Iqbal, J; Raymond, J; Gore, M; McIlwain, T J

1991-01-01

An immunoturbidimetric assay for the assessment of free kappa and lambda light chains of immunoglobulins was developed using a commercial polyclonal antiserum with reactivity towards epitopes on the light chains, which are not expressed when they are bound to heavy chains. The assay, on a centrifugal analyser, is simple and rapid. The limit of detection is 5 mg/l of free light chain, with an assay range of 5-120 mg/l, intrabatch precisions from 1.5-6.4%, and interbatch precisions from 6.5-8.9%. The assay was only slightly less sensitive than colloidal gold staining of cellulose acetate electrophoreses for the detection of Bence-Jones protein in urine. For the serial monitoring of response to chemotherapy in patients with myeloma, the assay correlated well with serum paraprotein estimates obtained by densitometric scanning of Ponceau stained cellulose acetate electrophoreses, but not with serum beta-2 microglobulin measurements, even after correction for the effects of creatinine. These assays may prove to be of use for the monitoring of tumour response in the treatment of Bence-Jones myeloma. PMID:1906071

Effect of diurnal photosynthetic activity on the fine structure of amylopectin from normal and waxy barley starch.

PubMed

Goldstein, Avi; Annor, George; Blennow, Andreas; Bertoft, Eric

2017-09-01

The impact of diurnal photosynthetic activity on the fine structure of the amylopectin fraction of starch synthesized by normal barley (NBS) and waxy barley (WBS), the latter completely devoid of amylose biosynthesis, was determined following the cultivation under normal diurnal or constant light growing conditions. The amylopectin fine structures were analysed by characterizing its unit chain length profiles after enzymatic debranching as well as its φ,β-limit dextrins and its clusters and building blocks after their partial and complete hydrolysis with α-amylase from Bacillus amyloliquefaciens, respectively. Regardless of lighting conditions, no structural effects were found when comparing both the amylopectin side-chain distribution and the internal chain fragments of these amylopectins. However, the diurnally grown NBS and WBS both showed larger amylopectin clusters and these had lower branching density and longer average chain lengths than clusters derived from plants grown under constant light conditions. Amylopectin clusters from diurnally grown plants also consisted of a greater number of building blocks, and shorter inter-block chain lengths compared to clusters derived from plants grown under constant light. Our data demonstrate that the diurnal light regime influences the fine structure of the amylopectin component both in amylose and non-amylose starch granules. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of light intensity on components and topographical structures of extracellular polysaccharides from the cyanobacteria Nostoc sp.

PubMed

Ge, Hongmei; Xia, Ling; Zhou, Xuping; Zhang, Delu; Hu, Chunxiang

2014-02-01

A study on the effects of light intensity (40 and 80 μE/m(2)/sec) on the components and topographical structures of extracellular polysaccharides (EPS) was carried out in cyanobacteria Nostoc sp.. EPS yield increased with light intensity. However, light intensity did not significantly affect the EPS fractions and monosaccharide composition. Higher light intensity generally resulted in higher protein content of EPS in similar fractions. The topographical structure of EPS, investigated by atomic force microscopy, appeared as spherical lumps, chains and networks. The long chains were observed at higher light intensity. Thus, light intensity affected the yield and nature of EPS.

[The H+/e- ratio in the photosynthetic electron transport chain].

PubMed

Ivanov, B N; Shmeleva, V L; Ovchinnikova, V I

1983-06-01

The number of protons adsorbed by tylakoids during one electron passage along the photosynthetic electron transport chain (i.e. the H+/e- ratio) was measured in isolated pea chloroplasts upon continuous illumination. Methylviologen was used as electron acceptor on the reducing side of PS I. It was found that at pH 6.0 upon illumination with red light (lambda greater than 620 nm) at an intensity of 2 . 10(5) erg/cm2 . s ("intensive" light) the H+/e- ratio is equal to 3. Upon illumination of dark-adapted chloroplasts with a "weak" light (900 erg/cm2 . s) the H+/e- ratio is equal to 2. Upon illumination of the chloroplasts with a "weak" after "intensive" light the value of this ratio is close to 3. Azide when added to the reaction mixture may interfere with the accuracy of measurements of the value of the H+/e- ratio by affecting proton exchange. Based on the changes in the H+/e- ratio induced by illumination it was assumed that at saturating intensity of the illuminating light the electron transport chain passes into a so-called "light" state when the mechanisms of proton-electron coupling differing from those of rare electron transfer ("weak" light, flashes) are triggered on. At pH 6.0 the "light" state of the electron transport chain is maintained for some time in the dark.

Triple Immunoglobulin Gene Knockout Transchromosomic Cattle: Bovine Lambda Cluster Deletion and Its Effect on Fully Human Polyclonal Antibody Production

PubMed Central

Matsushita, Hiroaki; Sano, Akiko; Wu, Hua; Jiao, Jin-an; Kasinathan, Poothappillai; Sullivan, Eddie J.; Wang, Zhongde; Kuroiwa, Yoshimi

2014-01-01

Towards the goal of producing fully human polyclonal antibodies (hpAbs or hIgGs) in transchromosomic (Tc) cattle, we previously reported that Tc cattle carrying a human artificial chromosome (HAC) comprising the entire unrearranged human immunoglobulin (Ig) heavy-chain (hIGH), kappa-chain (hIGK), and lambda-chain (hIGL) germline loci produced physiological levels of hIgGs when both of the bovine immunoglobulin mu heavy-chains, bIGHM and bIGHML1, were homozygously inactivated (bIGHM−/−, bIGHML1−/−; double knockouts or DKO). However, because endogenous bovine immunoglobulin light chain loci are still intact, the light chains are produced both from the hIGK and hIGL genomic loci on the HAC and from the endogenous bovine kappa-chain (bIGK) and lambda-chain (bIGL) genomic loci, resulting in the production of fully hIgGs (both Ig heavy-chains and light-chains are of human origin: hIgG/hIgκ or hIgG/hIgλ) and chimeric hIgGs (Ig heavy-chains are of human origin while the Ig light-chains are of bovine origin: hIgG/bIgκ or hIgG/bIgλ). To improve fully hIgG production in Tc cattle, we here report the deletion of the entire bIGL joining (J) and constant (C) gene cluster (bIGLJ1-IGLC1 to bIGLJ5-IGLC5) by employing Cre/loxP mediated site-specific chromosome recombination and the production of triple knockout (bIGHM−/−, bIGHML1−/− and bIGL−/−; TKO) Tc cattle. We further demonstrate that bIGL cluster deletion greatly improves fully hIgGs production in the sera of TKO Tc cattle, with 51.3% fully hIgGs (hIgG/hIgκ plus hIgG/hIgλ). PMID:24603704

Elucidating the Role of Residue 67 in IMP-Type Metallo-β-Lactamase Evolution.

PubMed

LaCuran, Alecander E; Pegg, Kevin M; Liu, Eleanor M; Bethel, Christopher R; Ai, Ni; Welsh, William J; Bonomo, Robert A; Oelschlaeger, Peter

2015-12-01

Antibiotic resistance in bacteria is ever changing and adapting, as once-novel β-lactam antibiotics are losing their efficacy, primarily due to the production of β-lactamases. Metallo-β-lactamases (MBLs) efficiently inactivate a broad range of β-lactam antibiotics, including carbapenems, and are often coexpressed with other antibacterial resistance factors. The rapid dissemination of MBLs and lack of novel antibacterials pose an imminent threat to global health. In an effort to better counter these resistance-conferring β-lactamases, an investigation of their natural evolution and resulting substrate specificity was employed. In this study, we elucidated the effects of different amino acid substitutions at position 67 in IMP-type MBLs on the ability to hydrolyze and confer resistance to a range of β-lactam antibiotics. Wild-type β-lactamases IMP-1 and IMP-10 and mutants IMP-1-V67A and IMP-1-V67I were characterized biophysically and biochemically, and MICs for Escherichia coli cells expressing these enzymes were determined. We found that all variants exhibited catalytic efficiencies (kcat/Km) equal to or higher than that of IMP-1 against all tested β-lactams except penicillins, against which IMP-1 and IMP-1-V67I showed the highest kcat/Km values. The substrate-specific effects of the different amino acid substitutions at position 67 are discussed in light of their side chain structures and possible interactions with the substrates. Docking calculations were employed to investigate interactions between different side chains and an inhibitor used as a β-lactam surrogate. The differences in binding affinities determined experimentally and computationally seem to be governed by hydrophobic interactions between residue 67 and the inhibitor and, by inference, the β-lactam substrates. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

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

Pham, Grace H.; Rana, Ambar S. J. B.; Korkmaz, E. Nihal

Ubiquitin (Ub) chains regulate a wide range of biological processes, and Ub chain connectivity is a critical determinant of the many regulatory roles that this post-translational modification plays in cells. To understand how distinct Ub chains orchestrate different biochemical events, we and other investigators have developed enzymatic and non-enzymatic methods to synthesize Ub chains of well-defined length and connectivity. A number of chemical approaches have been used to generate Ub oligomers connected by non-native linkages; however, few studies have examined the extent to which non-native linkages recapitulate the structural and functional properties associated with native isopeptide bonds. Here, we comparemore » the structure and function of Ub dimers bearing native and non-native linkages. Using small-angle X-ray scattering (SAXS) analysis, we show that scattering profiles for the two types of dimers are similar. Moreover, using an experimental structural library and atomistic simulations to fit the experimental SAXS profiles, we find that the two types of Ub dimers can be matched to analogous structures. An important application of non-native Ub oligomers is to probe the activity and selectivity of deubiquitinases. Through steady-state kinetic analyses, we demonstrate that different families of deubiquitinases hydrolyze native and non-native isopeptide linkages with comparable efficiency and selectivity. Considering the significant challenges associated with building topologically diverse native Ub chains, our results illustrate that chains harboring non-native linkages can serve as surrogate substrates for explorations of Ub function.« less

Light-induced Conversion of Trp to Gly and Gly Hydroperoxide in IgG1

PubMed Central

Haywood, Jessica; Mozziconacci, Olivier; Allegre, Kevin M.; Kerwin, Bruce A.; Schöneich, Christian

2013-01-01

The exposure of IgG1 in aqueous solution to light with λ = 254 nm or λ > 295 nm yields products consistent with Trp radical cation formation followed by αC-βC cleavage of the Trp side chain. The resulting glycyl radicals are either reduced to Gly, or add oxygen prior to reduction to Gly hydroperoxide. Photoirradiation at λ = 254 nm targets Trp at positions 191 (light chain), 309 and 377 (heavy chain) while photoirradiation at λ > 295 nm targets Trp at position 309 (heavy chain). Mechanistically, the formation of Trp radical cations likely proceeds via photo-induced electron- or hydrogen-transfer to disulfide bonds, yielding thiyl radicals and thiols, where thiols may serve as reductants for the intermediary glycyl or glycylperoxyl radicals. PMID:23363477

Subset of Kappa and Lambda Germline Sequences Result in Light Chains with a Higher Molecular Mass Phenotype.

PubMed

Barnidge, David R; Lundström, Susanna L; Zhang, Bo; Dasari, Surendra; Murray, David L; Zubarev, Roman A

2015-12-04

In our previous work, we showed that electrospray ionization of intact polyclonal kappa and lambda light chains isolated from normal serum generates two distinct, Gaussian-shaped, molecular mass distributions representing the light-chain repertoire. During the analysis of a large (>100) patient sample set, we noticed a low-intensity molecular mass distribution with a mean of approximately 24 250 Da, roughly 800 Da higher than the mean of the typical kappa molecular-mass distribution mean of 23 450 Da. We also observed distinct clones in this region that did not appear to contain any typical post-translational modifications that would account for such a large mass shift. To determine the origin of the high molecular mass clones, we performed de novo bottom-up mass spectrometry on a purified IgM monoclonal light chain that had a calculated molecular mass of 24 275.03 Da. The entire sequence of the monoclonal light chain was determined using multienzyme digestion and de novo sequence-alignment software and was found to belong to the germline allele IGKV2-30. The alignment of kappa germline sequences revealed ten IGKV2 and one IGKV4 sequences that contained additional amino acids in their CDR1 region, creating the high-molecular-mass phenotype. We also performed an alignment of lambda germline sequences, which showed additional amino acids in the CDR2 region, and the FR3 region of functional germline sequences that result in a high-molecular-mass phenotype. The work presented here illustrates the ability of mass spectrometry to provide information on the diversity of light-chain molecular mass phenotypes in circulation, which reflects the germline sequences selected by the immunoglobulin-secreting B-cell population.

Prognostic value of depressed midwall systolic function in cardiac light-chain amyloidosis.

PubMed

Perlini, Stefano; Salinaro, Francesco; Musca, Francesco; Mussinelli, Roberta; Boldrini, Michele; Raimondi, Ambra; Milani, Paolo; Foli, Andrea; Cappelli, Francesco; Perfetto, Federico; Palladini, Giovanni; Rapezzi, Claudio; Merlini, Giampaolo

2014-05-01

Cardiac amyloidosis represents an archetypal form of restrictive heart disease, characterized by profound diastolic dysfunction. As ejection fraction is preserved until the late stage of the disease, the majority of patients do fulfill the definition of diastolic heart failure, that is, heart failure with preserved ejection fraction (HFpEF). In another clinical model of HFpEF, that is, pressure-overload hypertrophy, depressed midwall fractional shortening (mFS) has been shown to be a powerful prognostic factor. To assess the potential prognostic role of mFS in cardiac light-chain amyloidosis with preserved ejection fraction, we enrolled 221 consecutive untreated patients, in whom a first diagnosis of cardiac light-chain amyloidosis was concluded between 2008 and 2010. HFpEF was present in 181 patients. Patients in whom cardiac involvement was excluded served as controls (n = 121). Prognosis was assessed after a median follow-up of 561 days. When compared with light-chain amyloidosis patients without myocardial involvement, cardiac light-chain amyloidosis was characterized by increased wall thickness (P <0.001), reduced end-diastolic left ventricular volumes (P <0.001), and diastolic dysfunction (P <0.001). In patients with preserved ejection fraction, mFS was markedly depressed [10.6% (8.7-13.5) vs. 17.8% (15.9-19.5) P <0.001]. At multivariable analysis, mFS, troponin I, and NT-pro-brain natriuretic peptide were the only significant prognostic determinants (P <0.001), whereas other indices of diastolic (E/E' ratio, transmitral and pulmonary vein flow velocities) and systolic function (tissue Doppler systolic indices, ejection fraction), or the presence/absence of congestive heart failure did not enter the model. In cardiac light-chain amyloidosis with normal ejection fraction, depressed circumferential mFS, a marker of myocardial contractile dysfunction, is a powerful predictor of survival.

Spectroscopic Studies of the Super Relaxed State of Skeletal Muscle

PubMed Central

Naber, Nariman; Pate, Edward; Canton, Marcella; Reggiani, Carlo; Cooke, Roger

2016-01-01

In the super-relaxed state of myosin, ATPase activity is strongly inhibited by binding of the myosin heads to the core of the thick filament in a structure known as the interacting-heads motif. In the disordered relaxed state myosin heads are not bound to the core of the thick filament and have an ATPase rate that is 10 fold greater. In the interacting-heads motif the two regulatory light chains appear to bind to each other. We have made single cysteine mutants of the regulatory light chain, placed both paramagnetic and fluorescent probes on them, and exchanged them into skinned skeletal muscle fibers. Many of the labeled light chains tended to disrupt the stability of the super-relaxed state, and showed spectral changes in the transition from the disordered relaxed state to the super-relaxed state. These data support the putative interface between the two regulatory light chains identified by cryo electron microscopy and show that both the divalent cation bound to the regulatory light chain and the N-terminus of the regulatory light chain play a role in the stability of the super-relaxed state. One probe showed a shift to shorter wavelengths in the super-relaxed state such that a ratio of intensities at 440nm to that at 520nm provided a measure of the population of the super-relaxed state amenable for high throughput screens for finding potential pharmaceuticals. The results provide a proof of concept that small molecules that bind to this region can destabilize the super-relaxed state and provide a method to search for small molecules that do so leading to a potentially effective treatment for Type 2 diabetes and obesity. PMID:27479128

A Toxoplasma gondii Class XIV Myosin, Expressed in Sf9 Cells with a Parasite Co-chaperone, Requires Two Light Chains for Fast Motility*

PubMed Central

Bookwalter, Carol S.; Kelsen, Anne; Leung, Jacqueline M.; Ward, Gary E.; Trybus, Kathleen M.

2014-01-01

Many diverse myosin classes can be expressed using the baculovirus/Sf9 insect cell expression system, whereas others have been recalcitrant. We hypothesized that most myosins utilize Sf9 cell chaperones, but others require an organism-specific co-chaperone. TgMyoA, a class XIVa myosin from the parasite Toxoplasma gondii, is required for the parasite to efficiently move and invade host cells. The T. gondii genome contains one UCS family myosin co-chaperone (TgUNC). TgMyoA expressed in Sf9 cells was soluble and functional only if the heavy and light chain(s) were co-expressed with TgUNC. The tetratricopeptide repeat domain of TgUNC was not essential to obtain functional myosin, implying that there are other mechanisms to recruit Hsp90. Purified TgMyoA heavy chain complexed with its regulatory light chain (TgMLC1) moved actin in a motility assay at a speed of ∼1.5 μm/s. When a putative essential light chain (TgELC1) was also bound, TgMyoA moved actin at more than twice that speed (∼3.4 μm/s). This result implies that two light chains bind to and stabilize the lever arm, the domain that amplifies small motions at the active site into the larger motions that propel actin at fast speeds. Our results show that the TgMyoA domain structure is more similar to other myosins than previously appreciated and provide a molecular explanation for how it moves actin at fast speeds. The ability to express milligram quantities of a class XIV myosin in a heterologous system paves the way for detailed structure-function analysis of TgMyoA and identification of small molecule inhibitors. PMID:25231988

Undiagnosed light chain systemic amyloidosis: does it matter to anesthesiologists? -a case report-

PubMed Central

Kim, Gwan Ho; Lee, Woo Kyung; Na, Se Hee

2013-01-01

Light chain systemic amyloidosis is rare but may accompany laryngeal or pulmonary involvement, which may increase the risk in airway management. We present a case of a patient planned for resection of cervical epidural mass. The patient had face and neck ecchymoses and purpuras with an unknown cause. Mask ventilation and intubation were successful, but the operation was cancelled to evaluate bleeding from facial skin lesions. A diagnosis of light chain systemic amyloidosis prompted evaluation of involvement of other organs and treatment. This case shows the importance of preoperative evaluation and careful airway management in patients with systemic amyloidosis. PMID:24363850

Light-assisted, templated self-assembly of gold nanoparticle chains.

PubMed

Jaquay, Eric; Martínez, Luis Javier; Huang, Ningfeng; Mejia, Camilo A; Sarkar, Debarghya; Povinelli, Michelle L

2014-09-10

We experimentally demonstrate the technique of light-assisted, templated self-assembly (LATS) to trap and assemble 200 nm diameter gold nanoparticles. We excite a guided-resonance mode of a photonic-crystal slab with 1.55 μm laser light to create an array of optical traps. Unlike our previous demonstration of LATS with polystyrene particles, we find that the interparticle interactions play a significant role in the resulting particle patterns. Despite a two-dimensionally periodic intensity profile in the slab, the particles form one-dimensional chains whose orientations can be controlled by the incident polarization of the light. The formation of chains can be understood in terms of a competition between the gradient force due to the excitation of the mode in the slab and optical binding between particles.

Caffeine enhances and accelerates the expression of sensitization induced by coca paste indicating its relevance as a main adulterant.

PubMed

Prieto, José P; Galvalisi, Martín; López-Hill, Ximena; Meikle, María N; Abin-Carriquiry, Juan A; Scorza, Cecilia

2015-08-01

Caffeine is an active adulterant found in several drugs of abuse including coca paste (CP). We had previously demonstrated that caffeine potentiated the acute stimulant effect induced by CP seized samples. The role of caffeine in the expression of sensitization elicited by a CP seized sample (CP1) was here evaluated. CP1 (equivalent dose of 10 mg/kg of cocaine), cocaine (pure, 10 mg/kg), a combination of cocaine 10 mg/kg plus caffeine 2.5 mg/kg (CP1-surrogate) and saline (control) were intraperitoneally injected in male rats under two different sensitization schedules. Ambulatory locomotion was recorded in 58 animals. After five daily CP1 injections and 5 days of withdrawal, CP1-challenged animals displayed a more robust sensitization than cocaine-treated animals. When a 3 injections-regime of CP1-surrogate or cocaine was assayed, only CP1-surrogate was able to elicit sensitization. Caffeine enhances and accelerates the CP1-induced sensitization. Results may shed light on the fast and high dependence observed in CP users. © American Academy of Addiction Psychiatry.

Construction and characterization of outbreak Escherichia coli O157:H7 surrogate strains for use in field studies.

PubMed

Webb, Cathy C; Erickson, Marilyn C; Davey, Lindsey E; Payton, Alison S; Doyle, Michael P

2014-11-01

Escherichia coli O157:H7 has been the causative agent of many outbreaks associated with leafy green produce consumption. Elucidating the mechanism by which contamination occurs requires monitoring interactions between the pathogen and the plant under typical production conditions. Intentional introduction of virulent strains into fields is not an acceptable practice. As an alternative, attenuated strains of natural isolates have been used as surrogates of the virulent strains; however, the attachment properties and environmental stabilities of these attenuated isolates may differ from the unattenuated outbreak strains. In this study, the Shiga toxin (stx1, stx2, and/or stx2c) genes as well as the eae gene encoding intimin of two E. coli O157:H7 outbreak isolates, F4546 (1997 alfalfa sprout) and K4492 (2006 lettuce), were deleted. Individual gene deletions were confirmed by polymerase chain reaction (PCR) and DNA sequencing. The mutant strains did not produce Shiga toxin. The growth kinetics of these mutant strains under nutrient-rich and minimal conditions were identical to those of their wild-type strains. Attachment to the surface of lettuce leaves was comparable between wild-type/mutant pairs F4546/MD46 and K4492/MD47. Adherence to soil particles was also comparable between the virulent and surrogate pairs, although the F4546/MD46 pair exhibited statistically greater attachment than the K4492/MD47 pair (p≤0.05). Wild-type and mutant pairs F4546/MD46 and K4492/MD47 inoculated into wet or dry soils had statistically similar survival rates over the 7-day storage period at 20°C. A plasmid, pGFPuv, containing green fluorescent protein was transformed into each of the mutant strains, allowing for ease of identification and detection of surrogate strains on plant material or soil. These pGFPuv-containing surrogate strains will enable the investigation of pathogen interaction with plants and soil in the farm production environment where the virulent pathogen cannot be used.

Paraprotein-Related Kidney Disease: Evaluation and Treatment of Myeloma Cast Nephropathy.

PubMed

Finkel, Kevin W; Cohen, Eric P; Shirali, Anushree; Abudayyeh, Ala

2016-12-07

Nearly 50% of patients with multiple myeloma develop renal disease, most commonly from AKI caused by cast nephropathy. Development of AKI is associated with poor 1-year survival and reduces the therapeutic options available to patients. There is a great need for more effective therapies. Cast nephropathy is caused by the interaction and aggregation of filtered free light chains and Tamm-Horsfall protein causing intratubular obstruction and damage. The key to treating cast nephropathy is rapid lowering of free light chains, because this correlates with renal recovery. Newer chemotherapy agents rapidly lower free light chains and have been referred to as renoprotective. There is additional great interest in using extracorporeal therapies to remove serum free light chains. Small trials initially showed benefit of therapeutic plasma exchange to improve renal outcomes in cast nephropathy, but a large randomized trial of therapeutic plasma exchange failed to show benefit. A newer technique is extended high-cutoff hemodialysis. This modality uses a high molecular weight cutoff filter to remove free light chains. To date, trials of high-cutoff hemodialysis use in patients with cast nephropathy have been encouraging. However, there are no randomized trials showing the benefit of high-cutoff hemodialysis when used in addition to newer chemotherapeutic regimens. Until these studies are available, high-cutoff hemodialysis cannot be recommended as standard of care. Copyright © 2016 by the American Society of Nephrology.

Crystal structure at 2.8 A of the DLLRKN-containing coiled-coil domain of huntingtin-interacting protein 1 (HIP1) reveals a surface suitable for clathrin light chain binding.

PubMed

Ybe, Joel A; Mishra, Sanjay; Helms, Stephen; Nix, Jay

2007-03-16

Huntingtin interacting protein 1 (HIP1) is a member of a family of proteins whose interaction with Huntingtin is critical to prevent cells from initiating apoptosis. HIP1, and related protein HIP12/1R, can also bind to clathrin and membrane phospholipids, and HIP12/1R links the CCV to the actin cytoskeleton. HIP1 and HIP12/1R interact with the clathrin light chain EED regulatory site and stimulate clathrin lattice assembly. Here, we report the X-ray structure of the coiled-coil domain of HIP1 (residues 482-586) that includes residues crucial for binding clathrin light chain. The dimeric HIP1 crystal structure is partially splayed open. The comparison of the HIP1 model with coiled-coil predictions revealed the heptad repeat in the dimeric trunk (S2 path) is offset relative to the register of the heptad repeat from the N-terminal portion (S1 path) of the molecule. Furthermore, surface analysis showed there is a third hydrophobic path (S3) running parallel with S1 and S2. We present structural evidence supporting a role for the S3 path as an interaction surface for clathrin light chain. Finally, comparative analysis suggests the mode of binding between sla2p and clathrin light chain may be different in yeast.

Effect of light chain V region duplication on IgG oligomerization and in vivo efficacy.

PubMed

Shuford, W; Raff, H V; Finley, J W; Esselstyn, J; Harris, L J

1991-05-03

A human immunoglobulin G1 (IgG1) antibody oligomer was isolated from a transfected myeloma cell line that produced a monoclonal antibody to group B streptococci. Compared to the IgG1 monomer, the oligomer was significantly more effective at protecting neonatal rats from infection in vivo. The oligomer was also shown to cross the placenta and to be stable in neonatal rats. Immunochemical analysis and complementary DNA sequencing showed that the transfected cell line produced two distinct kappa light chains: a normal light chain (Ln) with a molecular mass of 25 kilodaltons and a 37-kilodalton species (L37), the domain composition of which was variable-variable-constant (V-V-C). Cotransfection of vectors encoding the heavy chain and L37 resulted in production of oligomeric IgG.

Major immunoglobulin classes of the echidna (Tachyglossus aculeatus)

PubMed Central

Atwell, J. L.; Marchalonis, J. J.; Ealey, E. H. M.

1973-01-01

The Australian echidna responds to the antigen Salmonella adelaide flagella by producing antibodies characterized by mol. wt of 900,000 and 150,000. After cleavage of interchain disulphide bonds, both the high and low mol. wt immunoglobulins can be resolved into light and heavy polypeptide chains. In both cases, the light chains resemble those of other vertebrate immunoglobulins in size (22,500 Daltons) and electrophoretic mobility. The 900,000 Dalton immunoglobulin contains heavy chains similar to human μ chains in size (70,000 Daltons) and electrophoretic mobility. The 150,000 Dalton immunoglobulin contains a different class of heavy chain, similar in size (50,000 Daltons) and electrophoretic mobility to human γ chains. Proportional mass contributions of the light and heavy chains to the intact molecule suggest the structure of the intact molecules could be represented by (L2, μ2)5 and (L2, γ2) for the high and low mol. wt immunoglobulins respectively. These configurations are similar to those described for human γM and γG immunoglobulins. The results are relevant to theories of the evolution of the different classes of immunoglobulins. While the echidna is distinctly more primitive than eutherian mammals and still retains structural features characteristic of reptiles, its major immunoglobulin classes are very similar to human IgM and IgG. The striking similarities between the γ-like heavy chain of the echnidna and human IgG heavy chains suggest that the echidna may be the first species in which a γ chain gene directly homologous to mammalian γ chain genes is expressed. ImagesFIG. 4 PMID:4761634

Probing light chain mutation effects on thrombin via molecular dynamics simulations and machine learning.

PubMed

Xiao, Jiajie; Melvin, Ryan L; Salsbury, Freddie R

2018-03-02

Thrombin is a key component for chemotherapeutic and antithrombotic therapy development. As the physiologic and pathologic roles of the light chain still remain vague, here, we continue previous efforts to understand the impacts of the disease-associated single deletion of LYS9 in the light chain. By combining supervised and unsupervised machine learning methodologies and more traditional structural analyses on data from 10 μs molecular dynamics simulations, we show that the conformational ensemble of the ΔK9 mutant is significantly perturbed. Our analyses consistently indicate that LYS9 deletion destabilizes both the catalytic cleft and regulatory functional regions and result in some conformational changes that occur in tens to hundreds of nanosecond scaled motions. We also reveal that the two forms of thrombin each prefer a distinct binding mode of a Na + ion. We expand our understanding of previous experimental observations and shed light on the mechanisms of the LYS9 deletion associated bleeding disorder by providing consistent but more quantitative and detailed structural analyses than early studies in literature. With a novel application of supervised learning, i.e. the decision tree learning on the hydrogen bonding features in the wild-type and ΔK9 mutant forms of thrombin, we predict that seven pairs of critical hydrogen bonding interactions are significant for establishing distinct behaviors of wild-type thrombin and its ΔK9 mutant form. Our calculations indicate the LYS9 in the light chain has both localized and long-range allosteric effects on thrombin, supporting the opinion that light chain has an important role as an allosteric effector.

Successful treatment of nephrotic syndrome induced by lambda light chain deposition disease using lenalidomide: A case report and review of the literature
.

PubMed

Mima, Akira; Nagahara, Dai; Tansho, Kosuke

2018-06-01

Light chain deposition disease (LCDD) is a monoclonal immunoglobulin deposition disease (MIDD) that is characterized by the deposition of monoclonal light chains in multiple organs, including the kidney. It is a rare disorder caused by an underlying monoclonal plasma cell dyscrasia. LCDD with renal involvement causes proteinuria, which sometimes can lead to nephrotic syndrome. The monoclonal light chains are mostly in the κ form. Treatment of LCDD is the same as that for multiple myeloma (MM); however, some conventional anticancer drugs show substantial toxicity and therefore cannot be administered to older patients or those with renal impairment. An 80-year-old woman was referred to our department with severe nephrotic syndrome (13.6 g/gCr) and anemia. A renal biopsy showed mesangial proliferation and mesangial matrix expansion, and immunohistochemistry showed positive staining for λ chains along the glomerular basement membrane, but was negative for κ chains or amyloid deposition. A bone marrow biopsy revealed 64% plasma cells. Immunoglobulin G (IgG)-λ type M protein was detected, and the levels of free λ chain was significantly increased. We concluded that her nephrotic syndrome was caused by LCDD, which resulted from IgG-λ MM. The induction of a BCD (bortezomib, cyclophosphamide, and dexamethasone) treatment regimen did not lead to a hematological response or decrease in proteinuria. The administration of combination therapy of lenalidomide and prednisolone led to the successful reduction of proteinuria and hematuria. We presented a very rare case report describing the successful treatment of LCDD (λ chain)-induced nephrotic syndrome with lenalidomide.
.

Reduction of Bacterial Pathogens and Potential Surrogates on the Surface of Almonds Using High-Intensity 405-Nanometer Light.

PubMed

Lacombe, Alison; Niemira, Brendan A; Sites, Joseph; Boyd, Glenn; Gurtler, Joshua B; Tyrell, Breanna; Fleck, Melissa

2016-11-01

The disinfecting properties of high-intensity monochromatic blue light (MBL) were investigated against Escherichia coli O157:H7, Salmonella , and nonpathogenic bacteria inoculated onto the surface of almonds. MBL was generated from an array of narrow-band 405-nm light-emitting diodes. Almonds were inoculated with higher or lower levels (8 or 5 CFU/g) of pathogenic E. coli O157:H7 and Salmonella , as well as nonpathogenic E. coli K-12 and an avirulent strain of Salmonella Typhimurium, for evaluation as potential surrogates for their respective pathogens. Inoculated almonds were treated with MBL for 0, 1, 2, 4, 6, 8, and 10 min at a working distance of 7 cm. Simultaneous to treatment, cooling air was directed onto the almonds at a rate of 4 ft 3 /min (1.89 ×10 -3 m 3 /s), sourced through a container of dry ice. An infrared camera was used to monitor the temperature readings after each run. For E. coli K-12, reductions of up to 1.85 or 1.63 log CFU/g were seen for higher and lower inoculum levels, respectively; reductions up to 2.44 and 1.44 log CFU/g were seen for E. coli O157:H7 (higher and lower inoculation levels, respectively). Attenuated Salmonella was reduced by up to 0.54 and 0.97 log CFU/g, whereas pathogenic Salmonella was reduced by up to 0.70 and 0.55 log CFU/g (higher and lower inoculation levels, respectively). Inoculation level did not significantly impact minimum effective treatment times, which ranged from 1 to 4 min. Temperatures remained below ambient throughout treatment, indicating that MBL is a nonthermal antimicrobial process. The nonpathogenic strains of E. coli and Salmonella each responded to MBL in a comparable manner to their pathogenic counterparts. These results suggest that these nonpathogenic strains may be useful in experiments with MBL in which a surrogate is required, and that MBL warrants further investigation as a potential antimicrobial treatment for low-moisture foods.

Sequences of heavy and light chain variable regions from four bovine immunoglobulins.

PubMed

Armour, K L; Tempest, P R; Fawcett, P H; Fernie, M L; King, S I; White, P; Taylor, G; Harris, W J

1994-12-01

Oligodeoxyribonucleotide primers based on the 5' ends of bovine IgG1/2 and lambda constant (C) region genes, together with primers encoding conserved amino acids at the N-terminus of mature variable (V) regions from other species, have been used in cDNA and polymerase chain reactions (PCRs) to amplify heavy and light chain V region cDNA from bovine heterohybridomas. The amino acid sequences of VH and V lambda from four bovine immunoglobulins of different specificities are presented.

Catalysts for synthesizing various short chain hydrocarbons

DOEpatents

Colmenares, Carlos

1991-01-01

Method and apparatus (10), including novel photocatalysts, are disclosed for the synthesis of various short chain hydrocarbons. Light-transparent SiO.sub.2 aerogels doped with photochemically active uranyl ions (18) are fluidized in a fluidized-bed reactor (12) having a transparent window (16), by hydrogen and CO, C.sub.2 H.sub.4 or C.sub.2 H.sub.6 gas mixtures (20), and exposed to radiation (34) from a light source (32) external to the reactor (12), to produce the short chain hydrocarbons (36).

Influence of temperature and organic load on chemical disinfection of Geobacillus steareothermophilus spores, a surrogate for Bacillus anthracis

PubMed Central

Guan, Jiewen; Chan, Maria; Brooks, Brian W.; Rohonczy, Liz

2013-01-01

This study evaluated the influence of temperature and organic load on the effectiveness of domestic bleach (DB), Surface Decontamination Foam (SDF), and Virkon in inactivating Geobacillus stearothermophilus spores, which are a surrogate for Bacillus anthracis spores. The spores were suspended in light or heavy organic preparations and the suspension was applied to stainless steel carrier disks. The dried spore inoculum was covered with the disinfectants and the disks were then incubated at various temperatures. At −20°C, the 3 disinfectants caused less than a 2.0 log10 reduction of spores in both organic preparations during a 24-h test period. At 4°C, the DB caused a 4.4 log10 reduction of spores in light organic preparations within 2 h, which was about 3 log10 higher than what was achieved with SDF or Virkon. In heavy organic preparations, after 24 h at 4°C the SDF had reduced the spore count by 4.5 log10, which was about 2 log10 higher than for DB or Virkon. In general, the disinfectants were most effective at 23°C but a 24-h contact time was required for SDF and Virkon to reduce spore counts in both organic preparations by at least 5.5 log10. Comparable disinfecting activity with DB only occurred with the light organic load. In summary, at temperatures as low as 4°C, DB was the most effective disinfectant, inactivating spores within 2 h on surfaces with a light organic load, whereas SDF produced the greatest reduction of spores within 24 h on surfaces with a heavy organic load. PMID:24082400

Rapid polymerase chain reaction-based screening assay for bacterial biothreat agents.

PubMed

Yang, Samuel; Rothman, Richard E; Hardick, Justin; Kuroki, Marcos; Hardick, Andrew; Doshi, Vishal; Ramachandran, Padmini; Gaydos, Charlotte A

2008-04-01

To design and evaluate a rapid polymerase chain reaction (PCR)-based assay for detecting Eubacteria and performing early screening for selected Class A biothreat bacterial pathogens. The authors designed a two-step PCR-based algorithm consisting of an initial broad-based universal detection step, followed by specific pathogen identification targeted for identification of the Class A bacterial biothreat agents. A region in the bacterial 16S rRNA gene containing a highly variable sequence flanked by clusters of conserved sequences was chosen as the target for the PCR assay design. A previously described highly conserved region located within the 16S rRNA amplicon was selected as the universal probe (UniProbe, Integrated DNA Technology, Coralville, IA). Pathogen-specific TaqMan probes were designed for Bacillus anthracis, Yersinia pestis, and Francisella tularensis. Performance of the assay was assessed using genomic DNA extracted from the aforementioned biothreat-related organisms (inactivated or surrogate) and other common bacteria. The UniProbe detected the presence of all tested Eubacteria (31/31) with high analytical sensitivity. The biothreat-specific probes accurately identified organisms down to the closely related species and genus level, but were unable to discriminate between very close surrogates, such as Yersinia philomiragia and Bacillus cereus. A simple, two-step PCR-based assay proved capable of both universal bacterial detection and identification of select Class A bacterial biothreat and biothreat-related pathogens. Although this assay requires confirmatory testing for definitive species identification, the method has great potential for use in ED-based settings for rapid diagnosis in cases of suspected Category A bacterial biothreat agents.

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

Baden, Elizabeth M.; Owen, Barbara A.L.; Peterson, Francis C.

Amyloidoses are devastating and currently incurable diseases in which the process of amyloid formation causes fatal cellular and organ damage. The molecular mechanisms underlying amyloidoses are not well known. In this study, we address the structural basis of immunoglobulin light chain amyloidosis, which results from deposition of light chains produced by clonal plasma cells. We compare light chain amyloidosis protein AL-09 to its wild-type counterpart, the kl O18/O8 light chain germline. Crystallographic studies indicate that both proteins form dimers. However, AL-09 has an altered dimer interface that is rotated 90 degrees from the kl O18/O8 dimer interface. The three non-conservativemore » mutations in AL-09 are located within the dimer interface, consistent with their role in the decreased stability of this amyloidogenic protein. Moreover, AL-09 forms amyloid fibrils more quickly than kl O18/O8 in vitro. These results support the notion that the increased stability of the monomer and delayed fibril formation, together with a properly formed dimer, may be protective against amyloidogenesis. This could open a new direction into rational drug design for amyloidogenic proteins.« less

Light Chain Amyloid Fibrils Cause Metabolic Dysfunction in Human Cardiomyocytes

DOE PAGES

McWilliams-Koeppen, Helen P.; Foster, James S.; Hackenbrack, Nicole; ...

2015-09-22

Light chain (AL) amyloidosis is the most common form of systemic amyloid disease, and cardiomyopathy is a dire consequence, resulting in an extremely poor prognosis. AL is characterized by the production of monoclonal free light chains that deposit as amyloid fibrils principally in the heart, liver, and kidneys causing organ dysfunction. We have studied the effects of amyloid fibrils, produced from recombinant λ6 light chain variable domains, on metabolic activity of human cardiomyocytes. The data indicate that fibrils at 0.1 μM, but not monomer, significantly decrease the enzymatic activity of cellular NAD(P)H-dependent oxidoreductase, without causing significant cell death. The presencemore » of amyloid fibrils did not affect ATP levels; however, oxygen consumption was increased and reactive oxygen species were detected. Confocal fluorescence microscopy showed that fibrils bound to and remained at the cell surface with little fibril internalization. Ultimately, these data indicate that AL amyloid fibrils severely impair cardiomyocyte metabolism in a dose dependent manner. These data suggest that effective therapeutic intervention for these patients should include methods for removing potentially toxic amyloid fibrils.« less

Histopathologic and immunohistochemical features of Hashimoto thyroiditis.

PubMed

Amani, H Kazem

2011-01-01

Intrathyroid lymphoid tissue is accrued in Hashimoto thyroiditis (HT). Histologically, this acquired lymphoid tissue bears a close resemblance to mucosa-associated lymphoid tissue (MALT) and can evolve to lymphoma. To demonstrate the morphological, and immunohistochemical profiles of Hashimoto thyroiditis and to ascertain the importance of light chain restriction in distinguishing HT with extensive lymphoplasmacytoid infiltrate from MALT lymphoma. We studied histopathologically and immunohistochemically (CD20, CD3, Igk, Igl and cytokeratin) 30 cases of HT for evaluation of the lymphoid infiltrate and the presence of lymphoepithelial lesions (LELs). Distinguishing between early thyroid lymphoma and HT was evaluated by light chain restriction. These findings were compared with two cases of primary thyroid lymphoma. The histopathological findings were characteristic of HT. Immunohistochemistry confirmed inconspicuous, rare B-cell LELs as well as a prominent T-lymphocyte population. Testing for light chain restriction showed polyclonal population of plasma cells. The cases of MALT lymphoma had distinct destructive lymphoepithelial lesions, B-cell immunophenotyping and showed kappa light chain restriction in the plasmacytoid population. Hashimoto thyroiditis differs both histopathologically and immunohistochemically from thyroid lymphoma. In suspicious cases, immunohistochemistry could be helpful in reaching a definitive diagnosis.

A prospective study of nutritional status in immunoglobulin light chain amyloidosis

PubMed Central

Sattianayagam, Prayman T.; Lane, Thirusha; Fox, Zoe; Petrie, Aviva; Gibbs, Simon D.J.; Pinney, Jennifer H.; Risom, Signe S.; Rowczenio, Dorota M.; Wechalekar, Ashutosh D.; Lachmann, Helen J.; Gilbertson, Janet A.; Hawkins, Philip N.; Gillmore, Julian D.

2013-01-01

Weight loss is common in systemic immunoglobulin light chain amyloidosis but there are limited data on the impact of nutritional status on outcome. Using the Patient-Generated Subjective Global Assessment (PG-SGA) score, we prospectively examined nutritional status in 110 consecutive newly-diagnosed, treatment-naïve patients with immunoglobulin light chain amyloidosis attending the UK National Amyloidosis Centre. At study entry, 72 of 110 (66%) patients had a PG-SGA score of 4 or over, indicating malnutrition requiring specialist nutritional intervention. Number of amyloidotic organs, elevated alkaline phosphatase, presence of autonomic neuropathy and advanced Mayo disease stage were independently associated with poor nutritional status (P<0.05). Quality of life was substantially poorer among those with higher PG-SGA scores (P<0.001). Furthermore, PG-SGA score was a powerful independent predictor of patient survival (P=0.02). Malnutrition is prevalent and is associated with poor quality of life and reduced survival among patients with systemic immunoglobulin light chain amyloidosis. The PG-SGA score would be an appropriate tool to evaluate whether nutritional intervention could improve patient outcomes. PMID:22983575

Dynamics of a linear system coupled to a chain of light nonlinear oscillators analyzed through a continuous approximation

NASA Astrophysics Data System (ADS)

Charlemagne, S.; Ture Savadkoohi, A.; Lamarque, C.-H.

2018-07-01

The continuous approximation is used in this work to describe the dynamics of a nonlinear chain of light oscillators coupled to a linear main system. A general methodology is applied to an example where the chain has local nonlinear restoring forces. The slow invariant manifold is detected at fast time scale. At slow time scale, equilibrium and singular points are sought around this manifold in order to predict periodic regimes and strongly modulated responses of the system. Analytical predictions are in good accordance with numerical results and represent a potent tool for designing nonlinear chains for passive control purposes.

Plasmonic nanoparticle chain in a light field: a resonant optical sail.

PubMed

Albaladejo, Silvia; Sáenz, Juan José; Marqués, Manuel I

2011-11-09

Optical trapping and driving of small objects has become a topic of increasing interest in multidisciplinary sciences. We propose to use a chain made of metallic nanoparticles as a resonant light sail, attached by one end point to a transparent object and propelling it by the use of electromagnetic radiation. Driving forces exerted on the chain are theoretically studied as a function of radiation's wavelength and chain's alignments with respect to the direction of radiation. Interestingly, there is a window in the frequency spectrum in which null-torque equilibrium configuration, with minimum geometric cross section, corresponds to a maximum in the driving force.

Analysis of immunoglobulin heavy and light chain variable genes in post-transplant lymphoproliferative disorders.

PubMed

Capello, Daniela; Cerri, Michaela; Muti, Giuliana; Lucioni, Marco; Oreste, Pierluigi; Gloghini, Annunziata; Berra, Eva; Deambrogi, Clara; Franceschetti, Silvia; Rossi, Davide; Alabiso, Oscar; Morra, Enrica; Rambaldi, Alessandro; Carbone, Antonino; Paulli, Marco; Gaidano, Gianluca

2006-12-01

Post-transplant lymphoproliferative disorders (PTLD) derive from antigen-experienced B-cells and represent a major complication of solid organ transplantation. We characterized usage, mutation frequency and mutation pattern of immunoglobulin variable (IGV) gene rearrangements in 50 PTLD (polymorphic PTLD, n=10; diffuse large B-cell lymphoma, n=35; and Burkitt/Burkitt-like lymphoma, n=5). Among PTLD yielding clonal IGV amplimers, a functional IGV heavy chain (IGHV) rearrangement was found in 40/50 (80.0%) cases, whereas a potentially functional IGV light chain rearrangement was identified in 36/46 (78.3%) PTLD. By combining IGHV and IGV light chain rearrangements, 10/50 (20.0%) PTLD carried crippling mutations, precluding expression of a functional B-cell receptor (BCR). Immunohistochemistry showed detectable expression of IG light chains in only 18/43 (41.9%) PTLD. Failure to detect a functional IGV rearrangement associated with lack of IGV expression. Our data suggest that a large fraction of PTLD arise from germinal centre (GC)-experienced B-cells that display impaired BCR. Since a functional BCR is required for normal B-cell survival during GC transit, PTLD development may implicate rescue from apoptosis and expansion of B-cells that have failed the GC reaction. The high frequency of IGV loci inactivation appears to be a peculiar feature of PTLD among immunodeficiency-associated lymphoproliferations.

Measuring the quality of renal care: things to keep in mind when selecting and using quality indicators.

PubMed

van der Veer, Sabine N; van Biesen, Wim; Couchoud, Cécile; Tomson, Charles R V; Jager, Kitty J

2014-08-01

This educational paper discusses a variety of indicators that can be used to measure the quality of care in renal medicine. Based on what aspect of care they reflect, indicators can be grouped into four main categories: structure, process, surrogate outcome and outcome indicators. Each category has its own advantages and disadvantages, and we give some pointers on how to balance these pros and cons while taking into account the aim of the measurement initiative. Especially within initiatives that link payment or reputation to indicator measurement, this balancing should be done with utmost care to avoid potential, unintended consequences. Furthermore, we suggest consideration of (i) a causal chain-i.e. subsequent aspects of care connected by evidence-based links-as a starting point for composing a performance indicator set and (ii) adequate case-mix adjustment, not only of (surrogate) outcomes, but also of process indicators in order to obtain fair comparisons between facilities and within facilities over time. © The Author 2013. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Efficient Bayesian experimental design for contaminant source identification

NASA Astrophysics Data System (ADS)

Zhang, Jiangjiang; Zeng, Lingzao; Chen, Cheng; Chen, Dingjiang; Wu, Laosheng

2015-01-01

In this study, an efficient full Bayesian approach is developed for the optimal sampling well location design and source parameters identification of groundwater contaminants. An information measure, i.e., the relative entropy, is employed to quantify the information gain from concentration measurements in identifying unknown parameters. In this approach, the sampling locations that give the maximum expected relative entropy are selected as the optimal design. After the sampling locations are determined, a Bayesian approach based on Markov Chain Monte Carlo (MCMC) is used to estimate unknown parameters. In both the design and estimation, the contaminant transport equation is required to be solved many times to evaluate the likelihood. To reduce the computational burden, an interpolation method based on the adaptive sparse grid is utilized to construct a surrogate for the contaminant transport equation. The approximated likelihood can be evaluated directly from the surrogate, which greatly accelerates the design and estimation process. The accuracy and efficiency of our approach are demonstrated through numerical case studies. It is shown that the methods can be used to assist in both single sampling location and monitoring network design for contaminant source identifications in groundwater.

Control of norovirus outbreak on a pediatric oncology unit.

PubMed

Sheahan, Anna; Copeland, Gretchen; Richardson, Lauren; McKay, Shelley; Chou, Alexander; Babady, N Esther; Tang, Yi-Wei; Boulad, Farid; Eagan, Janet; Sepkowitz, Kent; Kamboj, Mini

2015-10-01

Patients undergoing treatment for cancer with chemotherapy and hematopoietic stem cell recipients are at risk for severe morbidity caused by norovirus (NV). We describe a NV outbreak on the Memorial Sloan Kettering Cancer Center's pediatric oncology unit. Stool testing for diagnosis of NV was performed by real-time polymerase chain reaction (PCR). Twelve NV cases occurred; 7 were hospital acquired. Twenty-five health care workers reported NV compatible illness. Patient-to-patient transmission occurred once. The practices of the Centers for Disease Control and Prevention were supplemented with electronic surveillance, surrogate screening for NV, and heightened cleaning. Two additional cases occurred after implementation of interventions. Long-term shedding was detected in 2 patients. We describe interventions for controlling NV on a pediatric oncology unit. High-risk chronic shedders pose ongoing transmission risks. PCR is a valuable diagnostic tool but may be overly sensitive. Surrogate markers to assess NV burden in stool and studies on NV screening are needed to develop guidelines for high-risk chronic shedders. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

A Computationally-Efficient Inverse Approach to Probabilistic Strain-Based Damage Diagnosis

NASA Technical Reports Server (NTRS)

Warner, James E.; Hochhalter, Jacob D.; Leser, William P.; Leser, Patrick E.; Newman, John A

2016-01-01

This work presents a computationally-efficient inverse approach to probabilistic damage diagnosis. Given strain data at a limited number of measurement locations, Bayesian inference and Markov Chain Monte Carlo (MCMC) sampling are used to estimate probability distributions of the unknown location, size, and orientation of damage. Substantial computational speedup is obtained by replacing a three-dimensional finite element (FE) model with an efficient surrogate model. The approach is experimentally validated on cracked test specimens where full field strains are determined using digital image correlation (DIC). Access to full field DIC data allows for testing of different hypothetical sensor arrangements, facilitating the study of strain-based diagnosis effectiveness as the distance between damage and measurement locations increases. The ability of the framework to effectively perform both probabilistic damage localization and characterization in cracked plates is demonstrated and the impact of measurement location on uncertainty in the predictions is shown. Furthermore, the analysis time to produce these predictions is orders of magnitude less than a baseline Bayesian approach with the FE method by utilizing surrogate modeling and effective numerical sampling approaches.

Audit of Use and Overuse of Serum Protein Immunofixation Electrophoresis and Serum Free Light Chain Assay in Tertiary Health Care: A Case for Algorithmic Testing to Optimize Laboratory Utilization.

PubMed

Heaton, Christopher; Vyas, Shikhar G; Singh, Gurmukh

2016-04-01

Overuse of laboratory tests is a persistent issue. We examined the use and overuse of serum immunofixation electrophoresis and serum free light chain assays to develop an algorithm for optimizing utilization. A retrospective review of all tests, for investigation of monoclonal gammopathies, for all patients who had any of these tests done from April 24, 2014, through July 25, 2014, was carried out. The test orders were categorized as warranted or not warranted according to criteria presented in the article. A total of 237 patients were tested, and their historical records included 1,503 episodes of testing for one or more of serum protein electrophoresis, serum immunofixation electrophoresis, and serum free light chain assays. Only 46% of the serum immunofixation and 42% serum free light chain assays were warranted. Proper utilization, at our institution alone, would have obviated $64,182.95/year in health care costs, reduced laboratory cost of reagent alone by $26,436.04/year, and put $21,904.92/year of part B reimbursement at risk. Fewer than half of the serum immunofixation and serum free light chain assays added value. The proposed algorithm for testing should improve utilization. Risk to part B billing may be a disincentive to reducing test utilization. © American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Crystal structure at 2.8 Å of the DLLRKN-containing coiled-coil domain of Huntingtin-interacting protein 1 (HIP1) reveals a surface suitable for clathrin light chain binding

PubMed Central

Ybe, Joel A.; Mishra, Sanjay; Helms, Stephen; Nix, Jay

2007-01-01

Summary Huntingtin interacting protein 1 (HIP1) is a member of a family of proteins whose interaction with Huntingtin is critical to prevent cells from initiating apoptosis. HIP1, and related protein HIP12/1R, can also bind to clathrin and membrane phospholipids and HIP12/1R links the CCV to the actin cytoskeleton. HIP1 and HIP12/1R interact with the clathrin light chain EED regulatory site and stimulate clathrin lattice assembly. Here we report the X-ray structure of the coiled-coil domain of HIP1 from 482–586 that includes residues crucial for binding clathrin light chain. The dimeric HIP1 crystal structure is partially splayed open. The comparison of the HIP1 model with coiled-coil predictions revealed the heptad repeat in the dimeric trunk (S2 path) is offset relative to the register of the heptad repeat from the N-terminal portion (S1 path) of the molecule. Furthermore, surface analysis showed there is a third hydrophobic path (S3) running parallel to S1 and S2. We present structural evidence supporting a role for S3 path as an interaction surface for clathrin light chain. Finally, comparative analysis suggests the mode of binding between sla2p and clathrin light chain may be different in yeast. PMID:17257618

Coordinate changes of myosin light and heavy chain isoforms during forced fiber type transitions in rabbit muscle.

PubMed

Leeuw, T; Pette, D

1996-01-01

Skeletal muscle fibers are versatile entities, capable of changing their phenotype in response to altered functional demands. In the present study, fast-to-slow fiber type transitions were induced in rabbit tibialis anterior (fA) muscles by chronic low-frequency stimulation (CLFS). The time course of changes in relative protein concentrations of fast and slow myosin light chain (MLC) isoforms and changes in their relative synthesis rates by in vivo labeling with [35S]methionine were followed during stimulation periods of up to 60 days. Generally, relative synthesis rates and protein concentrations changed in parallel; i.e., fast isoforms decreased and slow isoforms increased. MLC3f, however, which turns over at a higher rate than the other light chains, exhibited a conspicuous discrepancy between a markedly reduced relative synthesis but only a moderate decrease in protein amount during the initial 2 weeks of CLFS. Apparently, MLC3f is regulated independent of MLC1f, with protein degradation playing an important role in its regulation. The exchange of fast MLC isoforms with their slow counterparts seemed to correspond to the ultimate fast-to-slow (MHCIIa-->MHCI) transition at the MHC level. However, due to an earlier onset of the fast-to-slow transition of the regulatory light chain and the delayed fast-to-slow exchange of the alkali light chains, a spectrum of hybrid isomyosins composed of fast and slow light and heavy chains must have existed transiently in transforming fibers. Such hybrid isomyosins appeared to be restricted to MHCIIa- and MHCI-based combinations. In conclusion, fiber type specific programs that normally coordinate the expression of myofibrillar protein isoforms seem to be maintained during fiber type transitions. Possible differences in post-transcriptional regulation may result in the transient accumulation of atypical combinations of fast and slow MLC and MHC isoforms, giving rise to the appearance of hybrid fibers under the conditions of forced fiber type conversion.

How human IgGs against myelin basic protein (MBP) recognize oligopeptides and MBP.

PubMed

Belov, Sergey; Buneva, Valentina N; Nevinsky, Georgy A

2017-10-01

Myelin basic protein (MBP) is a major protein of myelin-proteolipid shell of axons, and it plays an important role in pathogenesis of multiple sclerosis. In the literature, there are no data on how antibodies recognize different protein antigens including MBP. A stepwise increase in ligand complexity was used to estimate the relative contributions of virtually every amino acid residue (AA) of a specific 12-mer LSRFSWGAEGQK oligopeptide corresponding to immunodominant sequence of MBP to the light chains and to intact anti-MBP IgGs from sera of patients with multiple sclerosis. It was shown that the minimal ligands of the light chains of IgGs are many different free AAs (K d  = 0.51-0.016 M), and each free AA interacts with the specific subsite of the light chain intended for recognition of this AA in specific LSRFSW oligopeptide. A gradual transition from Leu to LSRFSWGAEGQK leads to an increase in the affinity from 10 -1 to 2.3 × 10 -4  M because of additive interactions of the light chain with 6 AAs of this oligopeptide and then the affinity reaches plateau. The contributions of 6 various AAs to the affinity of the oligopeptide are different (K d , M): 0.71 (S), 0.44 (R), 0.14 (F), 0.17 (S), and 0.62 (W). Affinity of nonspecific oligopeptides to the light chains of IgGs is significantly lower. Intact MBP interacts with both light and heavy chains of IgGs demonstrating 192-fold higher affinity than the specific oligopeptide. It is a first quantitative analysis of the mechanism of proteins recognition by antibodies. The thermodynamic model was constructed to describe the interactions of IgGs with MBP. The data obtained can be very useful for understanding how antibodies against many different proteins can recognize these proteins. Copyright © 2017 John Wiley & Sons, Ltd.

Influence of fast and slow alkali myosin light chain isoforms on the kinetics of stretch-induced force transients of fast-twitch type IIA fibres of rat.

PubMed

Andruchov, Oleg; Galler, Stefan

2008-03-01

This study contributes to understand the physiological role of slow myosin light chain isoforms in fast-twitch type IIA fibres of skeletal muscle. These isoforms are often attached to the myosin necks of rat type IIA fibres, whereby the slow alkali myosin light chain isoform MLC1s is much more frequent and abundant than the slow regulatory myosin light chain isoform MLC2s. In the present study, single-skinned rat type IIA fibres were maximally Ca(2+) activated and subjected to stepwise stretches for causing a perturbation of myosin head pulling cycles. From the time course of the resulting force transients, myosin head kinetics was deduced. Fibres containing MLC1s exhibited slower kinetics independently of the presence or absence of MLC2s. At the maximal MLC1s concentration of about 75%, the slowing was about 40%. The slowing effect of MLC1s is possibly due to differences in the myosin heavy chain binding sites of the fast and slow alkali MLC isoforms, which changes the rigidity of the myosin neck. Compared with the impact of myosin heavy chain isoforms in various fast-twitch fibre types, the influence of MLC1s on myosin head kinetics of type IIA fibres is much smaller. In conclusion, the physiological role of fast and slow MLC isoforms in type IIA fibres is a fine-tuning of the myosin head kinetics.

Spin differences in the Zr 90 compound nucleus induced by ( p , p ' ) , ( p , d ) , and ( p , t ) surrogate reactions

DOE PAGES

Ota, S.; Burke, J. T.; Casperson, R. J.; ...

2015-11-04

Here, the effect of the production mechanism on the decay of a compound nucleus is investigated. The nucleus 90Zr was produced by three different reactions, namely 90Zr (p,p') 90Zr, 91Zr (p,d) 90Zr, and 92Zr (p,t) 90Zr , which served as surrogate reactions for 89Zr (n,γ). The spin-parity (J π) distributions of the states populated by these reactions were studied to investigate the surrogate reaction approach, which aims at indirectly determining cross sections for compound-nuclear reactions involving unstable targets such as 89Zr. Discrete γ rays, associated with transitions in 90Zr and 89Zr, were measured in coincidence with light ions for scatteringmore » angles of 25°–60° and 90Zr excitation energies extending above the neutron separation energy. The measured transition systematics were used to gain insights into the J π distributions of 90Zr. The 90Zr (p,p') reaction was found to produce fewer γ rays associated with transitions involving high spin states (J = 6–8 ℏ) than the other two reactions, suggesting that inelastic scattering preferentially populates states in 90Zr that have lower spins than those populated in the transfer reactions investigated. The γ-ray production was also observed to vary by factors of 2–3 with the angle at which the outgoing particle was detected. These findings are relevant to the application of the surrogate reaction approach.« less

Hsc70-induced Changes in Clathrin-Auxilin Cage Structure Suggest a Role for Clathrin Light Chains in Cage Disassembly

PubMed Central

Young, Anna; Stoilova-McPhie, Svetla; Rothnie, Alice; Vallis, Yvonne; Harvey-Smith, Phillip; Ranson, Neil; Kent, Helen; Brodsky, Frances M; Pearse, Barbara M F; Roseman, Alan; Smith, Corinne J

2013-01-01

The molecular chaperone, Hsc70, together with its co-factor, auxilin, facilitates the ATP-dependent removal of clathrin during clathrin-mediated endocytosis in cells. We have used cryo-electron microscopy to determine the 3D structure of a complex of clathrin, auxilin401-910 and Hsc70 at pH 6 in the presence of ATP, frozen within 20 seconds of adding Hsc70 in order to visualize events that follow the binding of Hsc70 to clathrin and auxilin before clathrin disassembly. In this map, we observe density beneath the vertex of the cage that we attribute to bound Hsc70. This density emerges asymmetrically from the clathrin vertex, suggesting preferential binding by Hsc70 for one of the three possible sites at the vertex. Statistical comparison with a map of whole auxilin and clathrin previously published by us reveals the location of statistically significant differences which implicate involvement of clathrin light chains in structural rearrangements which occur after Hsc70 is recruited. Clathrin disassembly assays using light scattering suggest that loss of clathrin light chains reduces the efficiency with which auxilin facilitates this reaction. These data support a regulatory role for clathrin light chains in clathrin disassembly in addition to their established role in regulating clathrin assembly. PMID:23710728

Managing Distance Education Institutions through Value Chain Analysis: the Nigerian Experience.

ERIC Educational Resources Information Center

Aderinto, J. A.; Akintayo, M. O.

Value chain analysis can gauge, analyze, and predict organization effects to control cost in light of achieving strategic organization objectives of distance education. Value chain analysis enables organizations to accomplish their goal or mission through cost effectiveness or differentiation. The value chain activity structure in a distance…

[Advances in the study of natural small molecular antibody].

PubMed

Zhu, Lei; Zhang, Da-peng

2012-10-01

Small molecule antibodies are naturally existed and well functioned but not structurally related to the conventional antibodies. They are only composed of heavy protein chains or light chains, much smaller than common antibody. The first small molecule antibody, called Nanobody was engineered from heavy-chain antibodies found in camelids. Cartilaginous fishes also have heavy-chain antibodies (IgNAR, "immunoglobulin new antigen receptor"), from which single-domain antibodies called Vnar fragments can be obtained. In addition, free light chain (FLC) antibodies in human bodies are being developed as therapeutic and diagnostic agents. Comparing to intact antibodies, common advantages of small molecule antibodies are with better solubility, tissue penetration, stability towards heat and enzymes, and comparatively low production costs. This article reviews the structural characteristics and mechanism of action of the Nanobody, IgNAR and FLC.

Development of U-frame bending system for studying the vibration integrity of spent nuclear fuel

NASA Astrophysics Data System (ADS)

Wang, Hong; Wang, Jy-An John; Tan, Ting; Jiang, Hao; Cox, Thomas S.; Howard, Rob L.; Bevard, Bruce B.; Flanagan, Michelle

2013-09-01

A bending fatigue system developed to evaluate the response of spent nuclear fuel rods to vibration loads is presented. A U-frame testing setup is used for imposing bending loads on the fuel rod specimen. The U-frame setup consists of two rigid arms, side connecting plates to the rigid arms, and linkages to a universal testing machine. The test specimen's curvature is obtained through a three-point deflection measurement method. The tests using surrogate specimens with stainless steel cladding revealed increased flexural rigidity under unidirectional cyclic bending, significant effect of cladding-pellets bonding on the response of surrogate rods, and substantial cyclic softening in reverse bending mode. These phenomena may cast light on the expected response of a spent nuclear fuel rod. The developed U-frame system is thus verified and demonstrated to be ready for further pursuit in hot-cell tests.

Purification, Characterization and Analysis of the Allergenic Properties of Myosin Light Chain in Procambarus clarkia.

USDA-ARS?s Scientific Manuscript database

Myosin light chain (MLC) plays a vital role in cell and muscle functions and has been identified as an allergen in close species. In this study, MLC with the molecular mass of 18kDa was purified from crayfish (Procambarus clarkii) muscle fibrils. Its physicochemical characterization showed that the...

Sequential cyclophosphamide-bortezomib-dexamethasone unmasks the harmful cardiac effect of dexamethasone in primary light-chain cardiac amyloidosis.

PubMed

Le Bras, Fabien; Molinier-Frenkel, Valerie; Guellich, Aziz; Dupuis, Jehan; Belhadj, Karim; Guendouz, Soulef; Ayad, Karima; Colombat, Magali; Benhaiem, Nicole; Tissot, Claire Marie; Hulin, Anne; Jaccard, Arnaud; Damy, Thibaud

2017-05-01

Chemotherapy combining cyclophosphamide, bortezomib and dexamethasone is widely used in light-chain amyloidosis. The benefit is limited in patients with cardiac amyloidosis mainly because of adverse cardiac events. Retrospective analysis of our cohort showed that 39 patients died with 42% during the first month. A new escalation-sequential regimen was set to improve the outcomes. Nine newly-diagnosed patients were prospectively treated with close monitoring of serum N-terminal pro-brain natriuretic peptide, troponin-T and free light chains. The results show that corticoids may destabilise the heart through fluid retention. Thus, a sequential protocol may be a promising approach to treat these patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of the suitability of a plant virus, pepper mild mottle virus, as a surrogate of human enteric viruses for assessment of the efficacy of coagulation-rapid sand filtration to remove those viruses.

PubMed

Shirasaki, N; Matsushita, T; Matsui, Y; Yamashita, R

2018-02-01

Here, we evaluated the removal of three representative human enteric viruses - adenovirus (AdV) type 40, coxsackievirus (CV) B5, and hepatitis A virus (HAV) IB - and one surrogate of human caliciviruses - murine norovirus (MNV) type 1 - by coagulation-rapid sand filtration, using water samples from eight water sources for drinking water treatment plants in Japan. The removal ratios of a plant virus (pepper mild mottle virus; PMMoV) and two bacteriophages (MS2 and φX174) were compared with the removal ratios of human enteric viruses to assess the suitability of PMMoV, MS2, and φX174 as surrogates for human enteric viruses. The removal ratios of AdV, CV, HAV, and MNV, evaluated via the real-time polymerase chain reaction (PCR) method, were 0.8-2.5-log 10 when commercially available polyaluminum chloride (PACl, basicity 1.5) and virgin silica sand were used as the coagulant and filter medium, respectively. The type of coagulant affected the virus removal efficiency, but the age of silica sand used in the rapid sand filtration did not. Coagulation-rapid sand filtration with non-sulfated, high-basicity PACls (basicity 2.1 or 2.5) removed viruses more efficiently than the other aluminum-based coagulants. The removal ratios of MS2 were sometimes higher than those of the three human enteric viruses and MNV, whereas the removal ratios of φX174 tended to be smaller than those of the three human enteric viruses and MNV. In contrast, the removal ratios of PMMoV were similar to and strongly correlated with those of the three human enteric viruses and MNV. Thus, PMMoV appears to be a suitable surrogate for human enteric viruses for the assessment of the efficacy of coagulation-rapid sand filtration to remove viruses. Copyright © 2017 Elsevier Ltd. All rights reserved.

Partitioning of polychlorinated biphenyls into human cells and adipose tissues: evaluation of octanol, triolein, and liposomes as surrogates.

PubMed

Quinn, Cristina L; van der Heijden, Stephan A; Wania, Frank; Jonker, Michiel T O

2014-05-20

Whereas octanol, triacylglycerides, and liposomes have all been proposed as surrogates for measuring the affinity of hydrophobic organic contaminants to human lipids, no comparative evaluation of their suitability exists. Here we conducted batch sorption experiments with polyoxymethylene passive samplers to determine the partition coefficients at 37 °C of 18 polychlorinated biphenyls (PCBs) from water into (i) triolein (Ktriolein/water), (ii) eight types of liposomes (Kliposome/water), (iii) human abdominal fat tissues (KAFT/water) from seven individuals, and (iv) human MCF-7 cells cultured in vitro (Kcell/water). Differences between KAFT/water among individuals and between Kliposome/water among liposome types were very small and not correlated to structural attributes of the PCBs. Similarly, the length and degree of saturation of the phospholipid carbon chains, the headgroup, and the composition of the liposome did not affect the partitioning of PCBs into the studied liposomes. Whereas Kliposome/water values were similar to literature values of Koctanol/water adjusted to 37 °C, they both were lower than KAFT/water and Kcell/water by a factor of 3 on average. Partitioning of PCBs into triolein on the other hand closely mimicked that into human lipids, for which triolein is thus a better surrogate than either octanol or liposomes. Previously published polyparameter linear free energy relationships for partitioning from water into storage lipids and liposomes predicted the measured partition coefficients with a root-mean-square error of less than 0.15 log units, if the chosen equations and solute descriptors do not allow chlorine substitution in the ortho-position to influence the prediction. By guiding the selection of (i) a surrogate for the experimental determination and (ii) a method for the prediction of partitioning into human lipids, this study contributes to a better assessment of hydrophobic organic contaminant bioaccumulation in humans.

Chimeric Anti-Human Podoplanin Antibody NZ-12 of Lambda Light Chain Exerts Higher Antibody-Dependent Cellular Cytotoxicity and Complement-Dependent Cytotoxicity Compared with NZ-8 of Kappa Light Chain.

PubMed

Kaneko, Mika K; Abe, Shinji; Ogasawara, Satoshi; Fujii, Yuki; Yamada, Shinji; Murata, Takeshi; Uchida, Hiroaki; Tahara, Hideaki; Nishioka, Yasuhiko; Kato, Yukinari

2017-02-01

Podoplanin (PDPN), a type I transmembrane 36-kDa glycoprotein, is expressed not only in normal cells, such as renal epithelial cells (podocytes), lymphatic endothelial cells, and pulmonary type I alveolar cells, but also in cancer cells, including brain tumors and lung squamous cell carcinomas. Podoplanin activates platelet aggregation by binding to C-type lectin-like receptor-2 (CLEC-2) on platelets, and the podoplanin/CLEC-2 interaction facilitates blood/lymphatic vessel separation. We previously produced neutralizing anti-human podoplanin monoclonal antibody (mAb), clone NZ-1 (rat IgG 2a , lambda), which neutralizes the podoplanin/CLEC-2 interaction and inhibits platelet aggregation and cancer metastasis. Human-rat chimeric antibody, NZ-8, was previously developed using variable regions of NZ-1 and human constant regions of heavy chain (IgG 1 ) and light chain (kappa chain). Although NZ-8 showed high antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) against human podoplanin-expressing cancer cells, the binding affinity of NZ-8 was lower than that of NZ-1. Herein, we produced a novel human-rat chimeric antibody, NZ-12, the constant regions of which consist of IgG 1 heavy chain and lambda light chain. Using flow cytometry, we demonstrated that the binding affinity of NZ-12 was much higher than that of NZ-8. Furthermore, ADCC and CDC activities of NZ-12 were significantly increased against glioblastoma cell lines (LN319 and D397) and lung cancer cell line (PC-10). These results suggested that NZ-12 could become a promising therapeutic antibody against podoplanin-expressing brain tumors and lung cancers.

Excessive amounts of mu heavy chain block B-cell development.

PubMed

Zhu, Lingqiao; Chang, Cheong-Hee; Dunnick, Wesley

2011-09-01

Antigen-independent B-cell development occurs in several stages that depend on the expression of Ig heavy and light chain. We identified a line of mice that lacked mature B cells in the spleen. This mouse line carried approximately 11 copies of a transgene of the murine heavy chain constant region locus, and B-lineage cells expressed excessive amounts of the intracellular μ heavy chain. B-cell development failed in the bone marrow at the pro/pre B-cell transition, and examination of other lines with various copy numbers of the same transgene suggested that deficiencies in B-cell development increased with increased transgene copy number. Expression of a transgenic (Tg) light chain along with the Tg μ heavy chain led to minimal rescue of B-cell development in the bone marrow and B cells in the spleen. There are several potential mechanisms for the death of pro/pre B cells as a consequence of excess heavy chain expression.

Generation of human scFv antibody libraries: PCR amplification and assembly of light- and heavy-chain coding sequences.

PubMed

Andris-Widhopf, Jennifer; Steinberger, Peter; Fuller, Roberta; Rader, Christoph; Barbas, Carlos F

2011-09-01

The development of therapeutic antibodies for use in the treatment of human diseases has long been a goal for many researchers in the antibody field. One way to obtain these antibodies is through phage-display libraries constructed from human lymphocytes. This protocol describes the construction of human scFv (single chain antibody fragment) libraries using a short linker (GGSSRSS) or a long linker (GGSSRSSSSGGGGSGGGG). In this method, the individual rearranged heavy- and light-chain variable regions are amplified separately and are linked through a series of overlap polymerase chain reaction (PCR) steps to give the final scFv products that are used for cloning.

Folding and trimerization of clathrin subunits at the triskelion hub.

PubMed

Näthke, I S; Heuser, J; Lupas, A; Stock, J; Turck, C W; Brodsky, F M

1992-03-06

The triskelion shape of the clathrin molecule enables it to form the polyhedral protein network that covers clathrin-coated pits and vesicles. Domains within the clathrin heavy chain that are responsible for maintaining triskelion shape and function were identified and localized. Sequences that mediate trimerization are distal to the carboxyl terminus and are adjacent to a domain that mediates both light chain binding and clathrin assembly. Structural modeling predicts that within this domain, the region of heavy chain-light chain interaction is a bundle of three or four alpha helices. These studies establish a low resolution model of clathrin subunit folding in the central portion (hub) of the triskelion, thus providing a basis for future mutagenesis experiments.

Inactivation kinetics and efficiencies of UV-LEDs against Pseudomonas aeruginosa, Legionella pneumophila, and surrogate microorganisms.

PubMed

Rattanakul, Surapong; Oguma, Kumiko

2018-03-01

To demonstrate the effectiveness of UV light-emitting diodes (UV-LEDs) to disinfect water, UV-LEDs at peak emission wavelengths of 265, 280, and 300 nm were adopted to inactivate pathogenic species, including Pseudomonas aeruginosa and Legionella pneumophila, and surrogate species, including Escherichia coli, Bacillus subtilis spores, and bacteriophage Qβ in water, compared to conventional low-pressure UV lamp emitting at 254 nm. The inactivation profiles of each species showed either a linear or sigmoidal survival curve, which both fit well with the Geeraerd's model. Based on the inactivation rate constant, the 265-nm UV-LED showed most effective fluence, except for with E. coli which showed similar inactivation rates at 265 and 254 nm. Electrical energy consumption required for 3-log 10 inactivation (E E,3 ) was lowest for the 280-nm UV-LED for all microbial species tested. Taken together, the findings of this study determined the inactivation profiles and kinetics of both pathogenic bacteria and surrogate species under UV-LED exposure at different wavelengths. We also demonstrated that not only inactivation rate constants, but also energy efficiency should be considered when selecting an emission wavelength for UV-LEDs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Surrogate measures and consistent surrogates

PubMed Central

VanderWeele, Tyler J.

2014-01-01

Summary Surrogates which allow one to predict the effect of the treatment on the outcome of interest from the effect of the treatment on the surrogate are of importance when it is difficult or expensive to measure the primary outcome. Unfortunately, the use of such surrogates can give rise to paradoxical situations in which the effect of the treatment on the surrogate is positive, the surrogate and outcome are strongly positively correlated, but the effect of the treatment on the outcome is negative, a phenomenon sometimes referred to as the "surrogate paradox." New results are given for consistent surrogates that extend the existing literature on sufficient conditions that ensure the surrogate paradox is not manifest. Specifically, it is shown that for the surrogate paradox to beman.est it must be the case that either there is (i) a direct effect of treatment on the outcome not through the surrogate and in the opposite direction as that through the surrogate or (ii) confounding for the effect of the surrogate on the outcome, or (iii) a lack of transitivity so that treatment does not positively affect the surrogate for all the same individuals for which the surrogate positively affects the outcome. The conditions for consistent surrogates and the results of the paper are important because they allow investigators to predict the direction of the effect of the treatment on the outcome simply from the direction of the effect of the treatment on the surrogate. These results on consistent surrogates are then related to the four approaches to surrogate outcomes described by Joffe and Greene (2009, Biometrics 65, 530–538) to assess whether the standard criterion used by these approaches to assess whether a surrogate is "good" suffices to avoid the surrogate paradox. PMID:24073861

Biomarkers in Immunoglobulin Light Chain Amyloidosis.

PubMed

Kufová, Z; Sevcikova, T; Growkova, K; Vojta, P; Filipová, J; Adam, Z; Pour, L; Penka, M; Rysava, R; Němec, P; Brozova, L; Vychytilova, P; Jurczyszyn, A; Grosicki, S; Barchnicka, A; Hajdúch, M; Simicek, M; Hájek, R

2017-01-01

Immunoglobulin light chain amyloidosis (AL amyloidosis - ALA) is a monoclonal gammopathy characterized by presence of aberrant plasma cells producing amyloidogenic immunoglobulin light chains. This leads to formation of amyloid fibrils in various organs and tissues, mainly in heart and kidney, and causes their dysfunction. As amyloid depositing in target organs is irreversible, there is a big effort to identify biomarker that could help to distinguish ALA from other monoclonal gammopathies in the early stages of disease, when amyloid deposits are not fatal yet. High throughput technologies bring new opportunities to modern cancer research as they enable to study disease within its complexity. Sophisticated methods such as next generation sequencing, gene expression profiling and circulating microRNA profiling are new approaches to study aberrant plasma cells from patients with light chain amyloidosis and related diseases. While generally known mutation in multiple myeloma patients (KRAS, NRAS, MYC, TP53) were not found in ALA, number of mutated genes is comparable. Transcriptome of ALA patients proves to be more similar to monoclonal gammopathy of undetermined significance patients, moreover level of circulating microRNA, that are known to correlate with heart damage, is increased in ALA patients, where heart damage in ALA typical symptom.Key words: amyloidosis - plasma cell - genome - transcriptome - microRNA.

Surrogate outcomes: experiences at the Common Drug Review

PubMed Central

2013-01-01

Background Surrogate outcomes are a significant challenge in drug evaluation for health technology assessment (HTA) agencies. The research objectives were to: identify factors associated with surrogate use and acceptability in Canada’s Common Drug Review (CDR) recommendations, and compare the CDR with other HTA or regulatory agencies regarding surrogate concerns. Methods Final recommendations were identified from CDR inception (September 2003) to December 31, 2010. Recommendations were classified by type of outcome (surrogate, final, other) and acceptability of surrogates (determined by the presence/absence of statements of concern regarding surrogates). Descriptive and statistical analyses examined factors related to surrogate use and acceptability. For thirteen surrogate-based submissions, recommendations from international HTA and regulatory agencies were reviewed for statements about surrogate acceptability. Results Of 156 final recommendations, 68 (44%) involved surrogates. The overall ‘do not list’ (DNL) rate was 48%; the DNL rate for surrogates was 41% (p = 0.175). The DNL rate was 64% for non-accepted surrogates (n = 28) versus 25% for accepted surrogates (odds ratio 5.4, p = 0.002). Clinical uncertainty, use of economic evidence over price alone, and a premium price were significantly associated with non-accepted surrogates. Surrogates were used most commonly for HIV, diabetes, rare diseases, cardiovascular disease and cancer. For the subset of drugs studied, other HTA agencies did not express concerns for most recommendations, while regulatory agencies frequently stated surrogate acceptance. Conclusions The majority of surrogates were accepted at the CDR. Non-accepted surrogates were significantly associated with clinical uncertainty and a DNL recommendation. There was inconsistency of surrogate acceptability across several international agencies. Stakeholders should consider collaboratively establishing guidelines on the use, validation, and acceptability of surrogates. PMID:24341379

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

PubMed Central

Yeow, Jonathan; Xu, Jiangtao; Boyer, Cyrille

2016-01-01

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (λ = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology. PMID:27340940

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst.

PubMed

Yeow, Jonathan; Xu, Jiangtao; Boyer, Cyrille

2016-06-08

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (λ = 460 nm, 0.7 mW/cm(2)), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

Diversity of immunoglobulin lambda light chain gene usage over developmental stages in the horse.

PubMed

Tallmadge, Rebecca L; Tseng, Chia T; Felippe, M Julia B

2014-10-01

To further studies of neonatal immune responses to pathogens and vaccination, we investigated the dynamics of B lymphocyte development and immunoglobulin (Ig) gene diversity. Previously we demonstrated that equine fetal Ig VDJ sequences exhibit combinatorial and junctional diversity levels comparable to those of adult Ig VDJ sequences. Herein, RACE clones from fetal, neonatal, foal, and adult lymphoid tissue were assessed for Ig lambda light chain combinatorial, junctional, and sequence diversity. Remarkably, more lambda variable genes (IGLV) were used during fetal life than later stages and IGLV gene usage differed significantly with time, in contrast to the Ig heavy chain. Junctional diversity measured by CDR3L length was constant over time. Comparison of Ig lambda transcripts to germline revealed significant increases in nucleotide diversity over time, even during fetal life. These results suggest that the Ig lambda light chain provides an additional dimension of diversity to the equine Ig repertoire. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Ahn, Wonmi; Zhao, Xin; Hong, Yan

Here, optoplasmonic structures contain plasmonic components embedded in a defined photonic environment to create synergistic interactions between photonic and plasmonic components. Here, we show that chains of optical microspheres containing gold nanoparticles in their evanescent field combine the light guiding properties of a microsphere chain with the light localizing properties of a plasmonic nanoantenna. We implement these materials through template guided self-assembly and investigate their fundamental electromagnetic working principles through combination of electromagnetic simulations and experimental characterization. We demonstrate that optoplasmonic chains implemented by directed self-assembly achieve a significant reduction in guiding losses when compared with conventional plasmonic waveguides and,more » at the same time, retain the light localizing properties of plasmonic antennas at pre-defined locations. The results reinforce the potential of optoplasmonic structures for realizing low-loss optical interconnects with high bandwidth.« less

INDUCTION OF RABBIT ANTIBODY WITH MOLECULAR UNIFORMITY AFTER IMMUNIZATION WITH GROUP C STREPTOCOCCI

PubMed Central

Eichmann, Klaus; Lackland, Henry; Hood, Leroy; Krause, Richard M.

1970-01-01

Antibodies with uniform properties may occur in rabbits after immunization with Group C streptococci. These precipitating antibodies possess specificity for the group-specific carbohydrate. Not uncommonly, their concentration is between 20 and 40 mg/ml of antiserum. Evidence for molecular uniformity in the case of one of these antibodies, described in detail here, includes: individual antigenic specificity; monodisperse distribution of the light chains by alkaline urea polyacrylamide disc electrophoresis; and a single amino acid in each of the first three N-terminal positions of the light chains. When the amino acid sequence of rabbit antibody b+ light chains (κ type) are aligned against their human κ counterparts, a definite homology is observed between the N-terminus of the human and the rabbit variable region. PMID:5409946

[Histopathological diagnosis of amyloidosis].

PubMed

Hoshii, Yoshinobu

2006-05-01

For the diagnosis of amyloidosis, histological evidence of amyloid deposition is essential. Histologically, an amyloid deposit is stained orange red with Congo red and shows green birefringence under polarized light. When amyloidosis is clinically suspected, endoscopic biopsy of the stomach, duodenum or colon, or aspiration biopsy of abdominal fat is usually performed. If clinicians suspect amyloidosis, they should advise pathologists. Identification of the chemical type of amyloid is necessary with respect to treatment and prognosis. Immunohistochemical examination of amyloid in formalin-fixed, paraffin-embedded sections is simple to perform in most pathological laboratories. In Japan, almost all cases of systemic amyloidosis are classified as AL, AA, ATTR or Abeta2M amyloidosis, so the use of anti-immunoglobulin light chain, anti-amyloid A, anti-transthyretin and anti-beta2 microglobulin antibody is recommended for the classification of systemic amyloidosis. Formic acid pretreatment, which is often used for immunohistochemical detection of amyloidosis, is useful and easy for antigen retrieval. Amyloid deposits of AL amyloidosis are sometimes not immunostained well with commercial anti-immunoglobulin light chain antibody. Previously, we generated polyclonal antibodies against synthetic peptides corresponding to positions 118-134 of immunoglobulin lambda light chain and positions 116-133 of immunoglobulin kappa light chain. These antibodies are very useful for detecting AL amyloidosis because they react with amyloid deposits on formalin-fixed, paraffin-embedded specimens in almost all AL amyloidosis cases. Exact diagnosis and typing of amyloidosis are necessary for therapy.

Biomarkers of the Hedgehog/Smoothened pathway in healthy volunteers

PubMed Central

Kadam, Sunil K; Patel, Bharvin K R; Jones, Emma; Nguyen, Tuan S; Verma, Lalit K; Landschulz, Katherine T; Stepaniants, Sergey; Li, Bin; Brandt, John T; Brail, Leslie H

2012-01-01

The Hedgehog (Hh) pathway is involved in oncogenic transformation and tumor maintenance. The primary objective of this study was to select surrogate tissue to measure messenger ribonucleic acid (mRNA) levels of Hh pathway genes for measurement of pharmacodynamic effect. Expression of Hh pathway specific genes was measured by quantitative real time polymerase chain reaction (qRT-PCR) and global gene expression using Affymetrix U133 microarrays. Correlations were made between the expression of specific genes determined by qRT-PCR and normalized microarray data. Gene ontology analysis using microarray data for a broader set of Hh pathway genes was performed to identify additional Hh pathway-related markers in the surrogate tissue. RNA extracted from blood, hair follicle, and skin obtained from healthy subjects was analyzed by qRT-PCR for 31 genes, whereas 8 samples were analyzed for a 7-gene subset. Twelve sample sets, each with ≤500 ng total RNA derived from hair, skin, and blood, were analyzed using Affymetrix U133 microarrays. Transcripts for several Hh pathway genes were undetectable in blood using qRT-PCR. Skin was the most desirable matrix, followed by hair follicle. Whether processed by robust multiarray average or microarray suite 5 (MAS5), expression patterns of individual samples showed co-clustered signals; both normalization methods were equally effective for unsupervised analysis. The MAS5- normalized probe sets appeared better suited for supervised analysis. This work provides the basis for selection of a surrogate tissue and an expression analysis-based approach to evaluate pathway-related genes as markers of pharmacodynamic effect with novel inhibitors of the Hh pathway. PMID:22611475

Neutron Protection Factor Determination and Validation for a Vehicle Surrogate Using a Californium Fission Source

DTIC Science & Technology

2017-06-01

protection factors . The success of this research is a direct result of the immense collaboration across a number of institutions that all shared a...at post detonation neutron transport, an exact solution is not needed. Instead, the RPF research campaign uses a statistical-based method through a... factors of selected light vehicles against residual radiation,” United States Army Ballistic Research Laboratory, Aberdeen Proving Ground, MD, 1988

Nuclear Structure Research at Richmond

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

Beausang, Cornelius W.

The goals for the final year were; (1) to continue ongoing efforts to develop and enhance GRETINA and work towards GRETA; (2) to investigate the structure of non-yrast states in shape transitional Sm and Gd nuclei; (3) to investigate the structure of selected light Cd nuclei; (4) to exploit the surrogate reaction technique to extract (n,f) cross sections for actinide nuclei, particularly the first measurement of the 236Pu and 237Pu(n,f) cross sections.

Conservative strategy-based ensemble surrogate model for optimal groundwater remediation design at DNAPLs-contaminated sites

NASA Astrophysics Data System (ADS)

Ouyang, Qi; Lu, Wenxi; Lin, Jin; Deng, Wenbing; Cheng, Weiguo

2017-08-01

The surrogate-based simulation-optimization techniques are frequently used for optimal groundwater remediation design. When this technique is used, surrogate errors caused by surrogate-modeling uncertainty may lead to generation of infeasible designs. In this paper, a conservative strategy that pushes the optimal design into the feasible region was used to address surrogate-modeling uncertainty. In addition, chance-constrained programming (CCP) was adopted to compare with the conservative strategy in addressing this uncertainty. Three methods, multi-gene genetic programming (MGGP), Kriging (KRG) and support vector regression (SVR), were used to construct surrogate models for a time-consuming multi-phase flow model. To improve the performance of the surrogate model, ensemble surrogates were constructed based on combinations of different stand-alone surrogate models. The results show that: (1) the surrogate-modeling uncertainty was successfully addressed by the conservative strategy, which means that this method is promising for addressing surrogate-modeling uncertainty. (2) The ensemble surrogate model that combines MGGP with KRG showed the most favorable performance, which indicates that this ensemble surrogate can utilize both stand-alone surrogate models to improve the performance of the surrogate model.

Phosphatase-inert glucosamine 6-phosphate mimics serve as actuators of the glmS riboswitch.

PubMed

Fei, Xiang; Holmes, Thomas; Diddle, Julianna; Hintz, Lauren; Delaney, Dan; Stock, Alex; Renner, Danielle; McDevitt, Molly; Berkowitz, David B; Soukup, Juliane K

2014-12-19

The glmS riboswitch is unique among gene-regulating riboswitches and catalytic RNAs. This is because its own metabolite, glucosamine-6-phosphate (GlcN6P), binds to the riboswitch and catalytically participates in the RNA self-cleavage reaction, thereby providing a novel negative feedback mechanism. Given that a number of pathogens harbor the glmS riboswitch, artificial actuators of this potential RNA target are of great interest. Structural/kinetic studies point to the 2-amino and 6-phosphate ester functionalities in GlcN6P as being crucial for this actuation. As a first step toward developing artificial actuators, we have synthesized a series of nine GlcN6P analogs bearing phosphatase-inert surrogates in place of the natural phosphate ester. Self-cleavage assays with the Bacillus cereus glmS riboswitch give a broad SAR. Two analogs display significant activity, namely, the 6-deoxy-6-phosphonomethyl analog (5) and the 6-O-malonyl ether (13). Kinetic profiles show a 22-fold and a 27-fold higher catalytic efficiency, respectively, for these analogs vs glucosamine (GlcN). Given their nonhydrolyzable phosphate surrogate functionalities, these analogs are arguably the most robust artificial glmS riboswitch actuators yet reported. Interestingly, the malonyl ether (13, extra O atom) is much more effective than the simple malonate (17), and the "sterically true" phosphonate (5) is far superior to the chain-truncated (7) or chain-extended (11) analogs, suggesting that positioning via Mg coordination is important for activity. Docking results are consistent with this view. Indeed, the viability of the phosphonate and 6-O-malonyl ether mimics of GlcN6P points to a potential new strategy for artificial actuation of the glmS riboswitch in a biological setting, wherein phosphatase-resistance is paramount.

Soluble stem cell factor receptor (CD117) and IL-2 receptor alpha chain (CD25) levels in the plasma of patients with mastocytosis: relationships to disease severity and bone marrow pathology.

PubMed

Akin, C; Schwartz, L B; Kitoh, T; Obayashi, H; Worobec, A S; Scott, L M; Metcalfe, D D

2000-08-15

Systemic mastocytosis is a disease of mast cell proliferation that may be associated with hematologic disorders. There are no features on examination that allow the diagnosis of systemic disease, and mast cell-derived mediators, which may be elevated in urine or blood, may also be elevated in individuals with severe allergic disorders. Thus, the diagnosis usually depends on results of bone marrow biopsy. To facilitate evaluation, surrogate markers of the extent and severity of the disease are needed. Because of the association of mastocytosis with hematologic disease, plasma levels were measured for soluble KIT (sKIT) and soluble interleukin-2 receptor alpha chain (sCD25), which are known to be cleaved in part from the mast cell surface and are elevated in some hematologic malignancies. Results revealed that levels of both soluble receptors are increased in systemic mastocytosis. Median plasma sKIT concentrations as expressed by AU/mL (1 AU = 1.4 ng/mL) were as follows: controls, 176 (n = 60); urticaria pigmentosa without systemic involvement, 194 (n = 8); systemic indolent mastocytosis, 511 (n = 30); systemic mastocytosis with an associated hematologic disorder, 1320 (n = 7); aggressive mastocytosis, 3390 (n = 3). Plasma sCD25 levels were elevated in systemic mastocytosis; the highest levels were associated with extensive bone marrow involvement. Levels of sKIT correlated with total tryptase levels, sCD25 levels, and bone marrow pathology. These results demonstrate that sKIT and sCD25 are useful surrogate markers of disease severity in patients with mastocytosis and should aid in diagnosis, in the selection of those needing a bone marrow biopsy, and in the documentation of disease progression. (Blood. 2000;96:1267-1273)

Munitions and Explosives of Concern Survey Methodology and In-field Testing for Wind Energy Areas on the Atlantic Outer Continental Shelf

NASA Astrophysics Data System (ADS)

DuVal, C.; Carton, G.; Trembanis, A. C.; Edwards, M.; Miller, J. K.

2017-12-01

Munitions and explosives of concern (MEC) are present in U.S. waters as a result of past and ongoing live-fire testing and training, combat operations, and sea disposal. To identify MEC that may pose a risk to human safety during development of offshore wind facilities on the Atlantic Outer Continental Shelf (OCS), the Bureau of Ocean Energy Management (BOEM) is preparing to develop guidance on risk analysis and selection processes for methods and technologies to identify MEC in Wind Energy Areas (WEA). This study developed a process for selecting appropriate technologies and methodologies for MEC detection using a synthesis of historical research, physical site characterization, remote sensing technology review, and in-field trials. Personnel were tasked with seeding a portion of the Delaware WEA with munitions surrogates, while a second group of researchers not privy to the surrogate locations tested and optimized the selected methodology to find and identify the placed targets. This in-field trial, conducted in July 2016, emphasized the use of multiple sensors for MEC detection, and led to further guidance for future MEC detection efforts on the Atlantic OCS. An April 2017 follow on study determined the fate of the munitions surrogates after the Atlantic storm season had passed. Using regional hydrodynamic models and incorporating the recommendations from the 2016 field trial, the follow on study examined the fate of the MEC and compared the findings to existing research on munitions mobility, as well as models developed as part of the Office of Naval Research Mine-Burial Program. Focus was given to characterizing the influence of sediment type on surrogate munitions behavior and the influence of mophodynamics and object burial on MEC detection. Supporting Mine-Burial models, ripple bedforms were observed to impede surrogate scour and burial in coarse sediments, while surrogate burial was both predicted and observed in finer sediments. Further, incorporation of recommendations from the previous trial in the 2017 study led to fourfold improvement of MEC detection rates over the 2016 approach. The use of modeling to characterize local morphodynamics, MEC burial or mobility, and the impact of seasonal or episodic storm events are discussed in light of technology selection and timing for future MEC detection surveys.

Complex of a Protective Antibody with its Ebola Virus GP Peptide Epitope: Unusual Features of a Vlambdalx Light Chain

DTIC Science & Technology

2008-01-01

Bioinformatics, 19, ii246–ii255. 52. Lawrence, M. C. & Colman, P. M. (1993). Shape complementarity at protein / protein interfaces . J. Mol. Biol. 234, 946...envelope spike, which is the sole protein expressed on the surface of the Ebola virus and is involved in receptor binding, tropism, and viral entry.6–9 It...variable light chain/heavy chain (VL/VH) interface of 13F6-1-2, ∼1025 Å2 surface area is buried on VL Fig. 1. Nucleotide and translated amino acid

Complex of a Protective Antibody with its Ebola Virus GP Peptide Epitope: Unusual Features of a V lambda x Light Chain

DTIC Science & Technology

2007-10-01

twists. Bioinformatics, 19, ii246–ii255. 52. Lawrence, M. C. & Colman, P. M. (1993). Shape complementarity at protein / protein interfaces . J. Mol. Biol...envelope spike, which is the sole protein expressed on the surface of the Ebola virus and is involved in receptor binding, tropism, and viral entry.6–9 It...26 At the variable light chain/heavy chain (VL/VH) interface of 13F6-1-2, ∼1025 Å2 surface area is buried on VL Fig. 1. Nucleotide and translated amino

Generation of human Fab antibody libraries: PCR amplification and assembly of light- and heavy-chain coding sequences.

PubMed

Andris-Widhopf, Jennifer; Steinberger, Peter; Fuller, Roberta; Rader, Christoph; Barbas, Carlos F

2011-09-01

The development of therapeutic antibodies for use in the treatment of human diseases has long been a goal for many researchers in the antibody field. One way to obtain these antibodies is through phage-display libraries constructed from human lymphocytes. This protocol describes the construction of human Fab (fragment antigen binding) antibody libraries. In this method, the individual rearranged heavy- and light-chain variable regions are amplified separately and are linked through a series of overlap polymerase chain reaction (PCR) steps to give the final Fab products that are used for cloning.

Blood-based cerebral biomarkers in preeclampsia: Plasma concentrations of NfL, tau, S100B and NSE during pregnancy in women who later develop preeclampsia - A nested case control study.

PubMed

Bergman, Lina; Zetterberg, Henrik; Kaihola, Helena; Hagberg, Henrik; Blennow, Kaj; Åkerud, Helena

2018-01-01

To evaluate if concentrations of the neuronal proteins neurofilament light chain and tau are changed in women developing preeclampsia and to evaluate the ability of a combination of neurofilament light chain, tau, S100B and neuron specific enolase in identifying neurologic impairment before diagnosis of preeclampsia. A nested case-control study within a longitudinal study cohort was performed. 469 healthy pregnant women were enrolled between 2004-2007 and plasma samples were collected at gestational weeks 10, 25, 28, 33 and 37. Plasma concentrations of tau and neurofilament light chain were analyzed in 16 women who eventually developed preeclampsia and 36 controls throughout pregnancy with single molecule array (Simoa) method and compared within and between groups. S100B and NSE had been analyzed previously in the same study population. A statistical model with receiving characteristic operation curve was constructed with the four biomarkers combined. Plasma concentrations of neurofilament light chain were significantly increased in women who developed preeclampsia in gestational week 33 (11.85 ng/L, IQR 7.48-39.93 vs 6.80 ng/L, IQR 5.65-11.40) and 37 (22.15 ng/L, IQR 10.93-35.30 vs 8.40 ng/L, IQR 6.40-14.30) and for tau in gestational week 37 (4.33 ng/L, IQR 3.97-12.83 vs 3.77 ng/L, IQR 1.91-5.25) in contrast to healthy controls. A combined model for preeclampsia with tau, neurofilament light chain, S100B and neuron specific enolase in gestational week 25 displayed an area under the curve of 0.77, in week 28 it was 0.75, in week 33 it was 0.89 and in week 37 it was 0.83. Median week for diagnosis of preeclampsia was at 38 weeks of gestation. Concentrations of both tau and neurofilament light chain are increased in the end of pregnancy in women developing preeclampsia in contrast to healthy pregnancies. Cerebral biomarkers might reflect cerebral involvement before onset of disease.

Using a surrogate contact pair to evaluate polyethylene wear in prosthetic knee joints.

PubMed

Sanders, Anthony P; Lockard, Carly A; Weisenburger, Joel N; Haider, Hani; Raeymaekers, Bart

2016-01-01

With recent improvements to the properties of ultra-high molecular weight polyethylene (UHMWPE) used in joint replacements, prosthetic knee and hip longevity may extend beyond two decades. However, it is difficult and costly to replicate such a long in vivo lifetime using clinically relevant in vitro wear testing approaches such as walking gait joint simulators. We advance a wear test intermediate in complexity between pin-on-disk and knee joint simulator tests. The test uses a surrogate contact pair, consisting of a surrogate femoral and tibial specimen that replicate the contact mechanics of any full-scale knee condyle contact pair. The method is implemented in a standard multi-directional pin-on-disk wear test machine, and we demonstrate its application via a two-million-cycle wear test of three different UHMWPE formulations. Further, we demonstrate the use of digital photography and image processing to accurately quantify fatigue damage based on the reduced transmission of light through a damage area in a UHMWPE specimen. The surrogate contact pairs replicate the knee condyle contact areas within -3% to +12%. The gravimetric wear test results reflect the dose of crosslinking radiation applied to the UHMWPE: 35 kGy yielded a wear rate of 7.4 mg/Mcycles, 55 kGy yielded 1.0 mg/Mcycles, and 75 kGy (applied to a 0.1% vitamin E stabilized UHMWPE) yielded 1.5 mg/Mcycles. A precursor to spalling fatigue is observed and precisely measured in the radiation-sterilized (35 kGy) and aged UHMWPE specimen. The presented techniques can be used to evaluate the high-cycle fatigue performance of arbitrary knee condyle contact pairs under design-specific contact stresses, using existing wear test machines. This makes the techniques more economical and well-suited to standardized comparative testing. © 2015 Wiley Periodicals, Inc.

Regions of recognition by blocking antibodies on the light chain of botulinum neurotoxin A: antigenic structure of the entire toxin.

PubMed

Dolimbek, Behzod Z; Steward, Lance E; Aoki, K Roger; Atassi, M Zouhair

2011-06-01

The continuous regions on botulinum neurotoxin A (BoNT/A) light (L) chain recognized by anti-toxin antibodies (Abs) from mouse, horse and chicken have been mapped. We synthesized a panel of thirty-two 19-residue peptides that overlapped consecutively by 5 residues and encompassed the entire L chain (residues 1-453). Mouse Abs recognized 5 major antigenic regions on the L chain, horse Abs recognized 9 while chicken Abs recognized 8 major antigenic regions. Overall, however, the three host species recognized, to some extent, similar, but not identical, peptides and the levels of Abs directed against a given region varied with the immunized host. Differences in the MHC of the host caused variation in levels of Ab recognition and some epitopes showed right or left frame-shifts among the species. Selected region(s) were also uniquely recognized by one species (e.g., peptide L1 by horse Abs). Mapping of the L chain antigenic regions and the previous localization of the regions on the H chain with the same antisera, has permitted description of the complete antigenic structure of BoNT/A. The locations in the 3-dimensional structure of the antigenic regions of the entire toxin are shown for mouse Abs. In the 3-D structure, the antigenic regions are on the surface of the toxin and when antibodies are bound the enzymatic activity of the light chain is obstructed. Copyright © 2010 Elsevier GmbH. All rights reserved.

Measurements of Light Absorbing Particles on Tropical South American Glaciers

NASA Astrophysics Data System (ADS)

Schmitt, C. G.; All, J.; Schwarz, J. P.; Arnott, W. P.; Warthon, J.; Andrade, M.; Celestian, A. J.; Hoffmann, D.; Cole, R. J.; Lapham, E.; Horodyskyj, U. N.; Froyd, K. D.; Liao, J.

2014-12-01

Glaciers in the tropical Andes have been losing mass rapidly in recent decades. In addition to the documented increase in temperature, increases in light absorbing particulates deposited on glaciers could be contributing to the observed glacier loss. Here we present results of measurements of light absorbing particles from glaciers in Peru and Bolivia. Samples have been collected by American Climber Science Program volunteers and scientists at altitudes up to 6770 meters. Collected snow samples were melted and filtered in the field. A new inexpensive technique, the Light Absorption Heating Method (LAHM) has been developed for analysis of light absorbing particles collected on filters. Results from LAHM analysis are calibrated using filters with known amounts of fullerene soot, a common industrial surrogate for black carbon (BC). For snow samples collected at the same field location LAHM analysis and measurements from the Single Particle Soot Photometer (SP2) instrument are well correlated (r2 = 0.92). Co-located SP2 and LAHM filter analysis suggest that BC could be the dominant absorbing component of the light absorbing particles in some areas.

Myosin Light Chain Kinase and the Role of Myosin Light Chain Phosphorylation in Skeletal Muscle

PubMed Central

Stull, James T.; Kamm, Kristine E.; Vandenboom, Rene

2011-01-01

Skeletal muscle myosin light chain kinase (skMLCK) is a dedicated Ca2+/calmodulin-dependent serine-threonine protein kinase that phosphorylates the regulatory light chain (RLC) of sarcomeric myosin. It is expressed from the MYLK2 gene specifically in skeletal muscle fibers with most abundance in fast contracting muscles. Biochemically, activation occurs with Ca2+ binding to calmodulin forming a (Ca2+)4•calmodulin complex sufficient for activation with a diffusion limited, stoichiometic binding and displacement of a regulatory segment from skMLCK catalytic core. The N-terminal sequence of RLC then extends through the exposed catalytic cleft for Ser15 phosphorylation. Removal of Ca2+ results in the slow dissociation of calmodulin and inactivation of skMLCK. Combined biochemical properties provide unique features for the physiological responsiveness of RLC phosphorylation, including (1) rapid activation of MLCK by Ca2+/calmodulin, (2) limiting kinase activity so phosphorylation is slower than contraction, (3) slow MLCK inactivation after relaxation and (4) much greater kinase activity relative to myosin light chain phosphatase (MLCP). SkMLCK phosphorylation of myosin RLC modulates mechanical aspects of vertebrate skeletal muscle function. In permeabilized skeletal muscle fibers, phosphorylation-mediated alterations in myosin structure increase the rate of force-generation by myosin cross bridges to increase Ca2+-sensitivity of the contractile apparatus. Stimulation-induced increases in RLC phosphorylation in intact muscle produces isometric and concentric force potentiation to enhance dynamic aspects of muscle work and power in unfatigued or fatigued muscle. Moreover, RLC phosphorylation-mediated enhancements may interact with neural strategies for human skeletal muscle activation to ameliorate either central or peripheral aspects of fatigue. PMID:21284933

DISTINCT ANTIBODY SPECIES: STRUCTURAL DIFFERENCES CREATING THERAPEUTIC OPPORTUNITIES

PubMed Central

Muyldermans, Serge; Smider, Vaughn V.

2016-01-01

Antibodies have been a remarkably successful class of molecules for binding a large number of antigens in therapeutic, diagnostic, and research applications. Typical antibodies derived from mouse or human sources use the surface formed by complementarity determining regions (CDRs) on the variable regions of the heavy chain/light chain heterodimer, which typically forms a relatively flat binding surface. Alternative species, particularly camelids and bovines, provide a unique paradigm for antigen recognition through novel domains which form the antigen binding paratope. For camelids, heavy chain antibodies bind antigen with only a single heavy chain variable region, in the absence of light chains. In bovines, ultralong CDR-H3 regions form an independently folding minidomain, which protrudes from the surface of the antibody and is diverse in both its sequence and disulfide patterns. The atypical paratopes of camelids and bovines potentially provide the ability to interact with different epitopes, particularly recessed or concave surfaces, compared to traditional antibodies. PMID:26922135

Track-structure simulations for charged particles.

PubMed

Dingfelder, Michael

2012-11-01

Monte Carlo track-structure simulations provide a detailed and accurate picture of radiation transport of charged particles through condensed matter of biological interest. Liquid water serves as a surrogate for soft tissue and is used in most Monte Carlo track-structure codes. Basic theories of radiation transport and track-structure simulations are discussed and differences compared to condensed history codes highlighted. Interaction cross sections for electrons, protons, alpha particles, and light and heavy ions are required input data for track-structure simulations. Different calculation methods, including the plane-wave Born approximation, the dielectric theory, and semi-empirical approaches are presented using liquid water as a target. Low-energy electron transport and light ion transport are discussed as areas of special interest.

Study on a hydroxypropyl chitosan-gelatin based scaffold for corneal stroma tissue engineering

NASA Astrophysics Data System (ADS)

Wang, Shilu; Liu, Wanshun; Han, Baoqin; Yang, Lingling

2009-07-01

Hydroxypropyl chitosan (HPCTS) was crosslinked with gelatin (GEL) and chondroitin sulfate (CS) by 1,4-butanediol diglycidyl ether to synthesize a scaffold. In this study, this scaffold was tested in physical and biological characteristics as a bioactive corneal stroma surrogate. The results showed the scaffold exhibited 83-88% light transmission values at wavelengths of visible light. Besides that, the scaffold had 96% water content and allowed NaCl and glucose to permeate. Moreover, it was suitable for keratocytes growing on its surface. In the biological part, we compared the scaffold with CS-free ones to investigate the potential effect of CS and found out that CS notablely improved cell compatibility of the scaffold.

The role of free kappa and lambda light chains in the pathogenesis and treatment of inflammatory diseases.

PubMed

Esparvarinha, Mojgan; Nickho, Hamid; Mohammadi, Hamed; Aghebati-Maleki, Leili; Abdolalizadeh, Jalal; Majidi, Jafar

2017-07-01

Kappa (κ) or lambda (λ) free light chains (FLCs) are produced from B cells during immunoglobulin synthesis. FLCs have been shown to participate in several key processes of immune responses. They are necessary to adjust PMN functions and assist PMN pre-stimulation. Moreover, they cause mast cell degranulation which releases pro-inflammatory mediators and stimulates local inflammatory responses in some conditions such as inflammatory bowel disease (IBD). Having low molecular weights which may straightly be toxic to proximal tubule cells (PTCs), FLCs can also have an important role in renal diseases. In this review we have highlighted the involvement of light chains in the pathogenesis of some inflammatory diseases and discussed their potential to be the targets of therapeutic purposes. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Hypophosphatemic osteomalacia: an unusual clinical presentation of multiple myeloma.

PubMed

Reyskens, M; Sleurs, K; Verresen, L; Janssen, M; van den Bergh, J; van den Berg, J; Geusens, P

2015-07-01

An unusual case of a 75-year-old man is presented who had multiple stress fractures due to adult onset hypophosphatemic osteomalacia, which was the result of Fanconi syndrome, with light chain cast proximal tubulopathy due to multiple myeloma. A 75-year-old man presented with diffuse pain and muscle weakness. He had multiple stress fractures, low serum phosphate, decreased renal tubular reabsorption of phosphate, and normal PTH and FGF23, indicating adult onset hypophosphatemic osteomalacia. Phosphate supplements with calcitriol resulted in clinical recovery and healing of stress fractures. Because of proteinuria, a renal biopsy was performed that revealed Fanconi syndrome with light chain cast proximal tubulopathy and light kappa chains were found in serum and urine. A bone biopsy confirmed the diagnosis of multiple myeloma, and treatment with chemotherapy resulted in cytological and clinical recovery.

Crystal Structure of a Phosphorylated Light Chain Domain of Scallop Smooth-Muscle Myosin

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

Kumar, V.S.; Robinson, H.; O-Neall-Hennessey, E.

2011-11-02

We have determined the crystal structure of a phosphorylated smooth-muscle myosin light chain domain (LCD). This reconstituted LCD is of a sea scallop catch muscle myosin with its phosphorylatable regulatory light chain (RLC SmoA). In the crystal structure, Arg{sup 16}, an arginine residue that is present in this isoform but not in vertebrate smooth-muscle RLC, stabilizes the phosphorylation site. This arginine interacts with the carbonyl group of the phosphorylation-site serine in the unphosphorylated LCD (determined previously), and with the phosphate group when the serine is phosphorylated. However, the overall conformation of the LCD is essentially unchanged upon phosphorylation. This resultmore » provides additional evidence that phosphorylation of the RLC is unlikely to act as an on-switch in regulation of scallop catch muscle myosin.« less

Case for diagnosis. Systemic light chain amyloidosis with cutaneous involvement*

PubMed Central

Gontijo, João Renato Vianna; Pinto, Jackson Machado; de Paula, Maysa Carla

2017-01-01

Systemic light chain amiloydosis is a rare disease. Due to its typical cutaneous lesions, dermatologists play an essential role in its diagnosis. Clinical manifestations vary according to the affected organ and are often unspecific. Definitive diagnosis is achieved through biopsy. We report a patient with palpebral amyloidosis, typical bilateral ecchymoses and cardiac involvement, without plasma cell dyscrasia or lymphomas. The patient died shortly after the diagnosis. PMID:29166521

Double phosphorylation of the myosin regulatory light chain during rigor mortis of bovine Longissimus muscle.

PubMed

Muroya, Susumu; Ohnishi-Kameyama, Mayumi; Oe, Mika; Nakajima, Ikuyo; Shibata, Masahiro; Chikuni, Koichi

2007-05-16

To investigate changes in myosin light chains (MyLCs) during postmortem aging of the bovine longissimus muscle, we performed two-dimensional gel electrophoresis followed by identification with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The results of fluorescent differential gel electrophoresis showed that two spots of the myosin regulatory light chain (MyLC2) at pI values of 4.6 and 4.7 shifted toward those at pI values of 4.5 and 4.6, respectively, by 24 h postmortem when rigor mortis was completed. Meanwhile, the MyLC1 and MyLC3 spots did not change during the 14 days postmortem. Phosphoprotein-specific staining of the gels demonstrated that the MyLC2 proteins at pI values of 4.5 and 4.6 were phosphorylated. Furthermore, possible N-terminal region peptides containing one and two phosphoserine residues were detected in each mass spectrum of the MyLC2 spots at pI values of 4.5 and 4.6, respectively. These results demonstrated that MyLC2 became doubly phosphorylated during rigor formation of the bovine longissimus, suggesting involvement of the MyLC2 phosphorylation in the progress of beef rigor mortis. Bovine; myosin regulatory light chain (RLC, MyLC2); phosphorylation; rigor mortis; skeletal muscle.

Evolution of EF-hand calcium-modulated proteins. IV. Exon shuffling did not determine the domain compositions of EF-hand proteins

NASA Technical Reports Server (NTRS)

Kretsinger, R. H.; Nakayama, S.

1993-01-01

In the previous three reports in this series we demonstrated that the EF-hand family of proteins evolved by a complex pattern of gene duplication, transposition, and splicing. The dendrograms based on exon sequences are nearly identical to those based on protein sequences for troponin C, the essential light chain myosin, the regulatory light chain, and calpain. This validates both the computational methods and the dendrograms for these subfamilies. The proposal of congruence for calmodulin, troponin C, essential light chain, and regulatory light chain was confirmed. There are, however, significant differences in the calmodulin dendrograms computed from DNA and from protein sequences. In this study we find that introns are distributed throughout the EF-hand domain and the interdomain regions. Further, dendrograms based on intron type and distribution bear little resemblance to those based on protein or on DNA sequences. We conclude that introns are inserted, and probably deleted, with relatively high frequency. Further, in the EF-hand family exons do not correspond to structural domains and exon shuffling played little if any role in the evolution of this widely distributed homolog family. Calmodulin has had a turbulent evolution. Its dendrograms based on protein sequence, exon sequence, 3'-tail sequence, intron sequences, and intron positions all show significant differences.

An Empirical Assessment and Comparison of Species-Based and Habitat-Based Surrogates: A Case Study of Forest Vertebrates and Large Old Trees

PubMed Central

Lindenmayer, David B.; Barton, Philip S.; Lane, Peter W.; Westgate, Martin J.; McBurney, Lachlan; Blair, David; Gibbons, Philip; Likens, Gene E.

2014-01-01

A holy grail of conservation is to find simple but reliable measures of environmental change to guide management. For example, particular species or particular habitat attributes are often used as proxies for the abundance or diversity of a subset of other taxa. However, the efficacy of such kinds of species-based surrogates and habitat-based surrogates is rarely assessed, nor are different kinds of surrogates compared in terms of their relative effectiveness. We use 30-year datasets on arboreal marsupials and vegetation structure to quantify the effectiveness of: (1) the abundance of a particular species of arboreal marsupial as a species-based surrogate for other arboreal marsupial taxa, (2) hollow-bearing tree abundance as a habitat-based surrogate for arboreal marsupial abundance, and (3) a combination of species- and habitat-based surrogates. We also quantify the robustness of species-based and habitat-based surrogates over time. We then use the same approach to model overall species richness of arboreal marsupials. We show that a species-based surrogate can appear to be a valid surrogate until a habitat-based surrogate is co-examined, after which the effectiveness of the former is lost. The addition of a species-based surrogate to a habitat-based surrogate made little difference in explaining arboreal marsupial abundance, but altered the co-occurrence relationship between species. Hence, there was limited value in simultaneously using a combination of kinds of surrogates. The habitat-based surrogate also generally performed significantly better and was easier and less costly to gather than the species-based surrogate. We found that over 30 years of study, the relationships which underpinned the habitat-based surrogate generally remained positive but variable over time. Our work highlights why it is important to compare the effectiveness of different broad classes of surrogates and identify situations when either species- or habitat-based surrogates are likely to be superior. PMID:24587050

An empirical assessment and comparison of species-based and habitat-based surrogates: a case study of forest vertebrates and large old trees.

PubMed

Lindenmayer, David B; Barton, Philip S; Lane, Peter W; Westgate, Martin J; McBurney, Lachlan; Blair, David; Gibbons, Philip; Likens, Gene E

2014-01-01

A holy grail of conservation is to find simple but reliable measures of environmental change to guide management. For example, particular species or particular habitat attributes are often used as proxies for the abundance or diversity of a subset of other taxa. However, the efficacy of such kinds of species-based surrogates and habitat-based surrogates is rarely assessed, nor are different kinds of surrogates compared in terms of their relative effectiveness. We use 30-year datasets on arboreal marsupials and vegetation structure to quantify the effectiveness of: (1) the abundance of a particular species of arboreal marsupial as a species-based surrogate for other arboreal marsupial taxa, (2) hollow-bearing tree abundance as a habitat-based surrogate for arboreal marsupial abundance, and (3) a combination of species- and habitat-based surrogates. We also quantify the robustness of species-based and habitat-based surrogates over time. We then use the same approach to model overall species richness of arboreal marsupials. We show that a species-based surrogate can appear to be a valid surrogate until a habitat-based surrogate is co-examined, after which the effectiveness of the former is lost. The addition of a species-based surrogate to a habitat-based surrogate made little difference in explaining arboreal marsupial abundance, but altered the co-occurrence relationship between species. Hence, there was limited value in simultaneously using a combination of kinds of surrogates. The habitat-based surrogate also generally performed significantly better and was easier and less costly to gather than the species-based surrogate. We found that over 30 years of study, the relationships which underpinned the habitat-based surrogate generally remained positive but variable over time. Our work highlights why it is important to compare the effectiveness of different broad classes of surrogates and identify situations when either species- or habitat-based surrogates are likely to be superior.

Structural basis of light chain amyloidogenicity: comparison of the thermodynamic properties, fibrillogenic potential and tertiary structural features of four vλ6 proteins

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

Wall, J.S.; Gupta, V.; Wilkerson, M.

2004-04-01

Primary (AL) amyloidosis results from the pathologic deposition of monoclonal light chains as amyloid fibrils. Studies of recombinant-derived variable region (V{sub L}) fragments of these proteins have shown an inverse relationship between thermodynamic stability and fibrillogenic potential. Further, ionic interactions within the V{sub L} domain were predicted to influence the kinetics of light chain fibrillogenicity, as evidenced from our analyses of a relatively stable V{sub {lambda}}6 protein (Jto) with a long range electrostatic interaction between Asp and Arg side chains at position 29 and 68, respectively, and an unstable, highly fibrillogenic V{sub {lambda}}6 protein (Wil) that had neutral amino acidsmore » at these locations. To test this hypothesis, we have generated two Jto-related mutants designed to disrupt the interaction between Asp 29 and Arg 68 (JtoD29A and JtoR68S). Although the thermodynamic stabilities of unfolding for these two molecules were identical, they exhibited very different kinetics of fibril formation: the rate of JtoD29A fibrillogenesis was slow and comparable to the parent molecule, whereas that of JtoR68S was significantly faster. High-resolution X-ray diffraction analyses of crystals prepared from the two mutants having the same space group and unit cell dimensions revealed no significant main-chain conformational changes. However, several notable side-chain alterations were observed in JtoR68S, as compared with JtoD29A, that resulted in the solvent exposure of a greater hydrophobic surface and modifications in the electrostatic potential surface. We posit that these differences contributed to the enhanced fibrillogenic potential of the Arg 68 mutant, since both Jto mutants lacked the intrachain ionic interaction and were equivalently unstable. The information gleaned from our studies has provided insight into structural parameters that in addition to overall thermodynamic stability, contribute to the fibril forming propensity of immunoglobulin light chains.« less

Flow-cytometric enrichment of Pacific bluefin tuna type A spermatogonia based on light-scattering properties.

PubMed

Ichida, Kensuke; Kise, Kazuyoshi; Morita, Tetsuro; Yazawa, Ryosuke; Takeuchi, Yutaka; Yoshizaki, Goro

2017-10-01

We previously established surrogate broodstock in which the donor germ cells transplanted into the peritoneal cavities of xenogeneic recipients were capable of developing into functional eggs and sperm in teleost fish. In this transplantation system, only the undifferentiated germ cells such as type A spermatogonia (ASG) or a portion of the ASG population were capable of being incorporated into the genital ridges of the recipients and undergo gametogenesis. Therefore, the use of enriched ASGs can be expected to achieve efficient donor-cell incorporation. Here, we established a method of isolation and enrichment of the ASG of Pacific bluefin tuna using flow cytometry. Whole testicular cell suspensions were fractionated by forward and side scatter properties, following which ASGs were enriched in a fraction in which the forward scatter signal was relatively high and side scatter signal was relatively low. The diameter of sorted cells using the fraction was identical to the size of ASGs observed in histological analysis, and these cells also expressed the vasa gene. In addition, we succeeded in applying this method to several maturation stages of Pacific bluefin tuna. Since this method was based on light-scattering characteristics of ASGs, it can potentially be applied to various teleosts. We expect that this method can contribute to the production of seeds of Pacific bluefin tuna using surrogate broodstock. Copyright © 2017 Elsevier Inc. All rights reserved.

Correlation between external and internal respiratory motion: a validation study.

PubMed

Ernst, Floris; Bruder, Ralf; Schlaefer, Alexander; Schweikard, Achim

2012-05-01

In motion-compensated image-guided radiotherapy, accurate tracking of the target region is required. This tracking process includes building a correlation model between external surrogate motion and the motion of the target region. A novel correlation method is presented and compared with the commonly used polynomial model. The CyberKnife system (Accuray, Inc., Sunnyvale/CA) uses a polynomial correlation model to relate externally measured surrogate data (optical fibres on the patient's chest emitting red light) to infrequently acquired internal measurements (X-ray data). A new correlation algorithm based on ɛ -Support Vector Regression (SVR) was developed. Validation and comparison testing were done with human volunteers using live 3D ultrasound and externally measured infrared light-emitting diodes (IR LEDs). Seven data sets (5:03-6:27 min long) were recorded from six volunteers. Polynomial correlation algorithms were compared to the SVR-based algorithm demonstrating an average increase in root mean square (RMS) accuracy of 21.3% (0.4 mm). For three signals, the increase was more than 29% and for one signal as much as 45.6% (corresponding to more than 1.5 mm RMS). Further analysis showed the improvement to be statistically significant. The new SVR-based correlation method outperforms traditional polynomial correlation methods for motion tracking. This method is suitable for clinical implementation and may improve the overall accuracy of targeted radiotherapy.

Surrogate decision making: do we have to trade off accuracy and procedural satisfaction?

PubMed

Frey, Renato; Hertwig, Ralph; Herzog, Stefan M

2014-02-01

Making surrogate decisions on behalf of incapacitated patients can raise difficult questions for relatives, physicians, and society. Previous research has focused on the accuracy of surrogate decisions (i.e., the proportion of correctly inferred preferences). Less attention has been paid to the procedural satisfaction that patients' surrogates and patients attribute to specific approaches to making surrogate decisions. The objective was to investigate hypothetical patients' and surrogates' procedural satisfaction with specific approaches to making surrogate decisions and whether implementing these preferences would lead to tradeoffs between procedural satisfaction and accuracy. Study 1 investigated procedural satisfaction by assigning participants (618 in a mixed-age but relatively young online sample and 50 in an older offline sample) to the roles of hypothetical surrogates or patients. Study 2 (involving 64 real multigenerational families with a total of 253 participants) investigated accuracy using 24 medical scenarios. Hypothetical patients and surrogates had closely aligned preferences: Procedural satisfaction was highest with a patient-designated surrogate, followed by shared surrogate decision-making approaches and legally assigned surrogates. These approaches did not differ substantially in accuracy. Limitations are that participants' preferences regarding existing and novel approaches to making surrogate decisions can only be elicited under hypothetical conditions. Next to decision making by patient-designated surrogates, shared surrogate decision making is the preferred approach among patients and surrogates alike. This approach appears to impose no tradeoff between procedural satisfaction and accuracy. Therefore, shared decision making should be further studied in representative samples of the general population, and if people's preferences prove to be robust, they deserve to be weighted more strongly in legal frameworks in addition to patient-designated surrogates.

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

Ota, S.; Burke, J. T.; Casperson, R. J.

Here, the effect of the production mechanism on the decay of a compound nucleus is investigated. The nucleus 90Zr was produced by three different reactions, namely 90Zr (p,p') 90Zr, 91Zr (p,d) 90Zr, and 92Zr (p,t) 90Zr , which served as surrogate reactions for 89Zr (n,γ). The spin-parity (J π) distributions of the states populated by these reactions were studied to investigate the surrogate reaction approach, which aims at indirectly determining cross sections for compound-nuclear reactions involving unstable targets such as 89Zr. Discrete γ rays, associated with transitions in 90Zr and 89Zr, were measured in coincidence with light ions for scatteringmore » angles of 25°–60° and 90Zr excitation energies extending above the neutron separation energy. The measured transition systematics were used to gain insights into the J π distributions of 90Zr. The 90Zr (p,p') reaction was found to produce fewer γ rays associated with transitions involving high spin states (J = 6–8 ℏ) than the other two reactions, suggesting that inelastic scattering preferentially populates states in 90Zr that have lower spins than those populated in the transfer reactions investigated. The γ-ray production was also observed to vary by factors of 2–3 with the angle at which the outgoing particle was detected. These findings are relevant to the application of the surrogate reaction approach.« less

Colour analysis and verification of CCTV images under different lighting conditions

NASA Astrophysics Data System (ADS)

Smith, R. A.; MacLennan-Brown, K.; Tighe, J. F.; Cohen, N.; Triantaphillidou, S.; MacDonald, L. W.

2008-01-01

Colour information is not faithfully maintained by a CCTV imaging chain. Since colour can play an important role in identifying objects it is beneficial to be able to account accurately for changes to colour introduced by components in the chain. With this information it will be possible for law enforcement agencies and others to work back along the imaging chain to extract accurate colour information from CCTV recordings. A typical CCTV system has an imaging chain that may consist of scene, camera, compression, recording media and display. The response of each of these stages to colour scene information was characterised by measuring its response to a known input. The main variables that affect colour within a scene are illumination and the colour, orientation and texture of objects. The effects of illumination on the appearance of colour of a variety of test targets were tested using laboratory-based lighting, street lighting, car headlights and artificial daylight. A range of typical cameras used in CCTV applications, common compression schemes and representative displays were also characterised.

Light Regulation of the Arabidopsis Respiratory Chain. Multiple Discrete Photoreceptor Responses Contribute to Induction of Type II NAD(P)H Dehydrogenase Genes1

PubMed Central

Escobar, Matthew A.; Franklin, Keara A.; Svensson, Å. Staffan; Salter, Michael G.; Whitelam, Garry C.; Rasmusson, Allan G.

2004-01-01

Controlled oxidation reactions catalyzed by the large, proton-pumping complexes of the respiratory chain generate an electrochemical gradient across the mitochondrial inner membrane that is harnessed for ATP production. However, several alternative respiratory pathways in plants allow the maintenance of substrate oxidation while minimizing the production of ATP. We have investigated the role of light in the regulation of these energy-dissipating pathways by transcriptional profiling of the alternative oxidase, uncoupling protein, and type II NAD(P)H dehydrogenase gene families in etiolated Arabidopsis seedlings. Expression of the nda1 and ndc1 NAD(P)H dehydrogenase genes was rapidly up-regulated by a broad range of light intensities and qualities. For both genes, light induction appears to be a direct transcriptional effect that is independent of carbon status. Mutant analyses demonstrated the involvement of two separate photoreceptor families in nda1 and ndc1 light regulation: the phytochromes (phyA and phyB) and an undetermined blue light photoreceptor. In the case of the nda1 gene, the different photoreceptor systems generate distinct kinetic induction profiles that are integrated in white light response. Primary transcriptional control of light response was localized to a 99-bp region of the nda1 promoter, which contains an I-box flanked by two GT-1 elements, an arrangement prevalent in the promoters of photosynthesis-associated genes. Light induction was specific to nda1 and ndc1. The only other substantial light effect observed was a decrease in aox2 expression. Overall, these results suggest that light directly influences the respiratory electron transport chain via photoreceptor-mediated transcriptional control, likely for supporting photosynthetic metabolism. PMID:15333756

SU-E-QI-15: Single Point Dosimetry by Means of Cerenkov Radiation Energy Transfer (CRET)

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

Volotskova, O; Jenkins, C; Xing, L

2014-06-15

Purpose: Cerenkov light is generated when a charged particles with energy greater then 250 keV, moves faster than the speed of light in a given medium. Both x-ray photons and electrons produce optical Cerenkov photons during the static megavoltage linear accelerator (LINAC) operational mode. Recently, Cerenkov radiation gained considerable interest as possible candidate as a new imaging modality. Optical signals generated by Cerenkov radiation may act as a surrogate for the absorbed superficial radiation dose. We demonstrated a novel single point dosimetry method for megavoltage photon and electron therapy utilizing down conversion of Cerenkov photons. Methods: The custom build signalmore » characterization system was used: a sample holder (probe) with adjacent light tight compartments was connected via fiber-optic cables to a photon counting photomultiplier tube (PMT). One compartment contains a medium only while the other contains medium and red-shifting nano-particles (Q-dots, nanoclusters). By taking the difference between the two signals (Cerenkov photons and CRET photons) we obtain a measure of the down-converted light, which we expect to be proportional to dose as measured with an adjacent ion chamber. Experimental results are compared to Monte Carlo simulations performed using the GEANT4 code. Results: The signal correlation between CR signal, CRET readings and dose produced by LINAC at a single point were investigated. The experimental results were compared with simulations. The dose linearity, signal to noise ratio and dose rate dependence were tested with custom build CRET based probe. Conclusion: Performance characteristics of the proposed single point CRET based probe were evaluated. The direct use of the induced Cerenkov emission and CRET in an irradiated single point volume as an indirect surrogate for the imparted dose was investigated. We conclude that CRET is a promising optical based dosimetry method that offers advantages over those already proposed.« less

Primary Ciliary Dyskinesia Caused by Homozygous Mutation in DNAL1, Encoding Dynein Light Chain 1

PubMed Central

Mazor, Masha; Alkrinawi, Soliman; Chalifa-Caspi, Vered; Manor, Esther; Sheffield, Val C.; Aviram, Micha; Parvari, Ruti

2011-01-01

In primary ciliary dyskinesia (PCD), genetic defects affecting motility of cilia and flagella cause chronic destructive airway disease, randomization of left-right body asymmetry, and, frequently, male infertility. The most frequent defects involve outer and inner dynein arms (ODAs and IDAs) that are large multiprotein complexes responsible for cilia-beat generation and regulation, respectively. Although it has long been suspected that mutations in DNAL1 encoding the ODA light chain1 might cause PCD such mutations were not found. We demonstrate here that a homozygous point mutation in this gene is associated with PCD with absent or markedly shortened ODA. The mutation (NM_031427.3: c.449A>G; p.Asn150Ser) changes the Asn at position150, which is critical for the proper tight turn between the β strand and the α helix of the leucine-rich repeat in the hydrophobic face that connects to the dynein heavy chain. The mutation reduces the stability of the axonemal dynein light chain 1 and damages its interactions with dynein heavy chain and with tubulin. This study adds another important component to understanding the types of mutations that cause PCD and provides clinical information regarding a specific mutation in a gene not yet known to be associated with PCD. PMID:21496787

Engineering botulinum neurotoxin domains for activation by toxin light chain.

PubMed

Stancombe, Patrick R; Masuyer, Geoffrey; Birch-Machin, Ian; Beard, Matthew; Foster, Keith A; Chaddock, John A; Acharya, K Ravi

2012-02-01

Targeted secretion inhibitors (TSI) are a new class of biopharmaceuticals designed from a botulinum neurotoxin protein scaffold. The backbone consists of the 50-kDa endopeptidase light chain and translocation domain (N-terminal portion of the heavy chain), lacks neuronal toxicity, but retains the ability to target cytoplasmic soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. TSI are produced as single-chain proteins and then cleaved post-translationally to generate functional heterodimers. Precise proteolytic cleavage is essential to activate the protein to a dichain form. TSI are themselves highly specific proteases. We have exploited this activity to create self-activating enzymes by replacing the native proteolytic site with a substrate SNARE peptide for the TSI protease. We have also created cross-activating backbones. By replacing the proteolytic activation site in one backbone with the substrate SNARE peptide for another serotype, controlled activation is achieved. SNARE peptides encompassing the whole of the coiled-coil region enabled complete activation and assembly of the dichain backbone. These engineered TSI backbones are capable of translocating their enzymatic domains to target intracellular SNARE proteins. They are also investigative tools with which to further the understanding of endopeptidase activity of light chain in SNARE interactions. © 2011 Syntaxin Ltd. Journal compilation © 2011 FEBS.

Ceria-thoria pellet manufacturing in preparation for plutonia-thoria LWR fuel production

NASA Astrophysics Data System (ADS)

Drera, Saleem S.; Björk, Klara Insulander; Sobieska, Matylda

2016-10-01

Thorium dioxide (thoria) has potential to assist in niche roles as fuel for light water reactors (LWRs). One such application for thoria is its use as the fertile component to burn plutonium in a mixed oxide fuel (MOX). Thor Energy and an international consortium are currently irradiating plutonia-thoria (Th-MOX) fuel in an effort to produce data for its licensing basis. During fuel-manufacturing research and development (R&D), surrogate materials were utilized to highlight procedures and build experience. Cerium dioxide (ceria) provides a good surrogate platform to replicate the chemical nature of plutonium dioxide. The project's fuel manufacturing R&D focused on powder metallurgical techniques to ensure manufacturability with the current commercial MOX fuel production infrastructure. The following paper highlights basics of the ceria-thoria fuel production including powder milling, pellet pressing and pellet sintering. Green pellets and sintered pellets were manufactured with average densities of 67.0% and 95.5% that of theoretical density respectively.

Fabrication and Characterization of Surrogate Fuel Particles Using the Spark Erosion Method

NASA Astrophysics Data System (ADS)

Metzger, Kathryn E.

In light of the disaster at the Fukushima Daiichi Nuclear Plant, the Department of Energy's Advanced Fuels Program has shifted its interest from enhanced performance fuels to enhanced accident tolerance fuels. Dispersion fuels possess higher thermal conductivities than traditional light water reactor fuel and as a result, offer improved safety margins. The benefits of a dispersion fuel are due to the presence of the secondary non-fissile phase (matrix), which serves as a barrier to fission products and improves the overall thermal performance of the fuel. However, the presence of a matrix material reduces the fuel volume, which lowers the fissile content of dispersion. This issue can be remedied through the development of higher density fuel phases or through an optimization of fuel particle size and volume loading. The latter requirement necessitates the development of fabrication methods to produce small, micron-order fuel particles. This research examines the capabilities of the spark erosion process to fabricate particles on the order of 10 μm. A custom-built spark erosion device by CT Electromechanica was used to produce stainless steel surrogate fuel particles in a deionized water dielectric. Three arc intensities were evaluated to determine the effect on particle size. Particles were filtered from the dielectric using a polycarbonate membrane filter and vacuum filtration system. Fabricated particles were characterized via field emission scanning electron microscopy (FESEM), laser light particle size analysis, energy-dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD), and gas pycnometry. FESEM images reveal that the spark erosion process produces highly spherical particles on the order of 10 microns. These findings are substantiated by the results of particle size analysis. Additionally, EDS and XRD results indicate the presence of oxide phases, which suggests the dielectric reacted with the molten debris during particle formation.

Epigallocatechin-3-gallate preferentially induces aggregation of amyloidogenic immunoglobulin light chains

PubMed Central

Hora, Manuel; Carballo-Pacheco, Martin; Weber, Benedikt; Morris, Vanessa K.; Wittkopf, Antje; Buchner, Johannes; Strodel, Birgit; Reif, Bernd

2017-01-01

Antibody light chain amyloidosis is a rare disease caused by fibril formation of secreted immunoglobulin light chains (LCs). The huge variety of antibody sequences puts a serious challenge to drug discovery. The green tea polyphenol epigallocatechin-3-gallate (EGCG) is known to interfere with fibril formation in general. Here we present solution- and solid-state NMR studies as well as MD simulations to characterise the interaction of EGCG with LC variable domains. We identified two distinct EGCG binding sites, both of which include a proline as an important recognition element. The binding sites were confirmed by site-directed mutagenesis and solid-state NMR analysis. The EGCG-induced protein complexes are unstructured. We propose a general mechanistic model for EGCG binding to a conserved site in LCs. We find that EGCG reacts selectively with amyloidogenic mutants. This makes this compound a promising lead structure, that can handle the immense sequence variability of antibody LCs. PMID:28128355

Two Decades of Cardiovascular Trials With Primary Surrogate Endpoints: 1990-2011.

PubMed

Bikdeli, Behnood; Punnanithinont, Natdanai; Akram, Yasir; Lee, Ike; Desai, Nihar R; Ross, Joseph S; Krumholz, Harlan M

2017-03-21

Surrogate endpoint trials test strategies more efficiently but are accompanied by uncertainty about the relationship between changes in surrogate markers and clinical outcomes. We identified cardiovascular trials with primary surrogate endpoints published in the New England Journal of Medicine , Lancet , and JAMA: Journal of the American Medical Association from 1990 to 2011 and determined the trends in publication of surrogate endpoint trials and the success of the trials in meeting their primary endpoints. We tracked for publication of clinical outcome trials on the interventions tested in surrogate trials. We screened 3016 articles and identified 220 surrogate endpoint trials. From the total of 220 surrogate trials, 157 (71.4%) were positive for their primary endpoint. Only 59 (26.8%) surrogate trials had a subsequent clinical outcomes trial. Among these 59 trials, 24 outcomes trial results validated the positive surrogates, whereas 20 subsequent outcome trials were negative following positive results on a surrogate. We identified only 3 examples in which the surrogate trial was negative but a subsequent outcomes trial was conducted and showed benefit. Findings were consistent in a sample cohort of 383 screened articles inclusive of 37 surrogate endpoint trials from 6 other high-impact journals. Although cardiovascular surrogate outcomes trials frequently show superiority of the tested intervention, they are infrequently followed by a prominent outcomes trial. When there was a high-profile clinical outcomes study, nearly half of the positive surrogate trials were not validated. Cardiovascular surrogate outcome trials may be more appropriate for excluding benefit from the patient perspective than for identifying it. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst

PubMed Central

Theriot, Jordan C.; Ryan, Matthew D.; French, Tracy A.; Pearson, Ryan M.; Miyake, Garret M.

2016-01-01

A standardized technique for atom transfer radical polymerization of vinyl monomers using perylene as a visible-light photocatalyst is presented. The procedure is performed under an inert atmosphere using air- and water-exclusion techniques. The outcome of the polymerization is affected by the ratios of monomer, initiator, and catalyst used as well as the reaction concentration, solvent, and nature of the light source. Temporal control over the polymerization can be exercised by turning the visible light source off and on. Low dispersities of the resultant polymers as well as the ability to chain-extend to form block copolymers suggest control over the polymerization, while chain end-group analysis provides evidence supporting an atom-transfer radical polymerization mechanism. PMID:27166728

Opinion: the red-light response of stomatal movement is sensed by the redox state of the photosynthetic electron transport chain.

PubMed

Busch, Florian A

2014-02-01

Guard cells regulate CO2 uptake and water loss of a leaf by controlling stomatal movement in response to environmental factors such as CO2, humidity, and light. The mechanisms by which stomata respond to red light are actively debated in the literature, and even after decades of research it is still controversial whether stomatal movement is related to photosynthesis or not. This review summarizes the current knowledge of the red-light response of stomata. A comparison of published evidence suggests that stomatal movement is controlled by the redox state of photosynthetic electron transport chain components, in particular the redox state of plastoquinone. Potential consequences for the modeling of stomatal conductance are discussed.

Immunoglobulin λ Gene Rearrangement Can Precede κ Gene Rearrangement

DOE PAGES

Berg, Jörg; Mcdowell, Mindy; Jäck, Hans-Martin; ...

1990-01-01

Imore » mmunoglobulin genes are generated during differentiation of B lymphocytes by joining gene segments. A mouse pre-B cell contains a functional immunoglobulin heavy-chain gene, but no light-chain gene. Although there is only one heavy-chain locus, there are two lightchain loci: κ and λ .t has been reported that κ loci in the germ-line configuration are never (in man) or very rarely (in the mouse) present in cells with functionally rearranged λ -chain genes. Two explanations have been proposed to explain this: (a) the ordered rearrangement theory, which postulates that light-chain gene rearrangement in the pre-B cell is first attempted at the κ locus, and that only upon failure to produce a functional κ chain is there an attempt to rearrange the λ locus; and (b) the stochastic theory, which postulates that rearrangement at the λ locus proceeds at a rate that is intrinsically much slower than that at the κ locus. We show here that λ -chain genes are generated whether or not the κ locus has lost its germ-line arrangement, a result that is compatible only with the stochastic theory.« less

When monoclonal antibodies are not monospecific: Hybridomas frequently express additional functional variable regions

PubMed Central

Bradbury, Andrew R. M.; Trinklein, Nathan D.; Wilkinson, Ian C.; Tandon, Atul K.; Anderson, Stephen; Bladen, Catherine L.; Jones, Brittany; Aldred, Shelley Force; Bestagno, Marco; Burrone, Oscar; Maynard, Jennifer; Ferrara, Fortunato; Görnemann, Janina; Glanville, Jacob; Wolf, Philipp; Frenzel, Andre; Wong, Julin; Koh, Xin Yu; Eng, Hui-Yan; Lane, David; Lefranc, Marie-Paule; Clark, Mike

2018-01-01

ABSTRACT Monoclonal antibodies are commonly assumed to be monospecific, but anecdotal studies have reported genetic diversity in antibody heavy chain and light chain genes found within individual hybridomas. As the prevalence of such diversity has never been explored, we analyzed 185 random hybridomas, in a large multicenter dataset. The hybridomas analyzed were not biased towards those with cloning difficulties or known to have additional chains. Of the hybridomas we evaluated, 126 (68.1%) contained no additional productive chains, while the remaining 59 (31.9%) contained one or more additional productive heavy or light chains. The expression of additional chains degraded properties of the antibodies, including specificity, binding signal and/or signal-to-noise ratio, as determined by enzyme-linked immunosorbent assay and immunohistochemistry. The most abundant mRNA transcripts found in a hybridoma cell line did not necessarily encode the antibody chains providing the correct specificity. Consequently, when cloning antibody genes, functional validation of all possible VH and VL combinations is required to identify those with the highest affinity and lowest cross-reactivity. These findings, reflecting the current state of hybridomas used in research, reiterate the importance of using sequence-defined recombinant antibodies for research or diagnostic use. PMID:29485921

A phage display vector optimized for the generation of human antibody combinatorial libraries and the molecular cloning of monoclonal antibody fragments.

PubMed

Solforosi, Laura; Mancini, Nicasio; Canducci, Filippo; Clementi, Nicola; Sautto, Giuseppe Andrea; Diotti, Roberta Antonia; Clementi, Massimo; Burioni, Roberto

2012-07-01

A novel phagemid vector, named pCM, was optimized for the cloning and display of antibody fragment (Fab) libraries on the surface of filamentous phage. This vector contains two long DNA "stuffer" fragments for easier differentiation of the correctly cut forms of the vector. Moreover, in pCM the fragment at the heavy-chain cloning site contains an acid phosphatase-encoding gene allowing an easy distinction of the Escherichia coli cells containing the unmodified form of the phagemid versus the heavy-chain fragment coding cDNA. In pCM transcription of heavy-chain Fd/gene III and light chain is driven by a single lacZ promoter. The light chain is directed to the periplasm by the ompA signal peptide, whereas the heavy-chain Fd/coat protein III is trafficked by the pelB signal peptide. The phagemid pCM was used to generate a human combinatorial phage display antibody library that allowed the selection of a monoclonal Fab fragment antibody directed against the nucleoprotein (NP) of Influenza A virus.

Estimation of k-ε parameters using surrogate models and jet-in-crossflow data

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

Lefantzi, Sophia; Ray, Jaideep; Arunajatesan, Srinivasan

2014-11-01

We demonstrate a Bayesian method that can be used to calibrate computationally expensive 3D RANS (Reynolds Av- eraged Navier Stokes) models with complex response surfaces. Such calibrations, conditioned on experimental data, can yield turbulence model parameters as probability density functions (PDF), concisely capturing the uncertainty in the parameter estimates. Methods such as Markov chain Monte Carlo (MCMC) estimate the PDF by sampling, with each sample requiring a run of the RANS model. Consequently a quick-running surrogate is used instead to the RANS simulator. The surrogate can be very difficult to design if the model's response i.e., the dependence of themore » calibration variable (the observable) on the parameter being estimated is complex. We show how the training data used to construct the surrogate can be employed to isolate a promising and physically realistic part of the parameter space, within which the response is well-behaved and easily modeled. We design a classifier, based on treed linear models, to model the "well-behaved region". This classifier serves as a prior in a Bayesian calibration study aimed at estimating 3 k - ε parameters ( C μ, C ε2 , C ε1 ) from experimental data of a transonic jet-in-crossflow interaction. The robustness of the calibration is investigated by checking its predictions of variables not included in the cal- ibration data. We also check the limit of applicability of the calibration by testing at off-calibration flow regimes. We find that calibration yield turbulence model parameters which predict the flowfield far better than when the nomi- nal values of the parameters are used. Substantial improvements are still obtained when we use the calibrated RANS model to predict jet-in-crossflow at Mach numbers and jet strengths quite different from those used to generate the ex- perimental (calibration) data. Thus the primary reason for poor predictive skill of RANS, when using nominal values of the turbulence model parameters, was parametric uncertainty, which was rectified by calibration. Post-calibration, the dominant contribution to model inaccuraries are due to the structural errors in RANS.« less

In vivo roles for myosin phosphatase targeting subunit-1 phosphorylation sites T694 and T852 in bladder smooth muscle contraction

PubMed Central

Chen, Cai-Ping; Chen, Xin; Qiao, Yan-Ning; Wang, Pei; He, Wei-Qi; Zhang, Cheng-Hai; Zhao, Wei; Gao, Yun-Qian; Chen, Chen; Tao, Tao; Sun, Jie; Wang, Ye; Gao, Ning; Kamm, Kristine E; Stull, James T; Zhu, Min-Sheng

2015-01-01

Force production and maintenance in smooth muscle is largely controlled by different signalling modules that fine tune myosin regulatory light chain (RLC) phosphorylation, which relies on a balance between Ca2+/calmodulin-dependent myosin light chain kinase (MLCK) and myosin light chain phosphatase (MLCP) activities. To investigate the regulation of MLCP activity in vivo, we analysed the role of two phosphorylation sites on MYPT1 (regulatory subunit of MLCP) that biochemically inhibit MLCP activity in vitro. MYPT1 is constitutively phosphorylated at T694 by unidentified kinases in vivo, whereas the T852 site is phosphorylated by RhoA-associated protein kinase (ROCK). We established two mouse lines with alanine substitution of T694 or T852. Isolated bladder smooth muscle from T852A mice displayed no significant changes in RLC phosphorylation or force responses, but force was inhibited with a ROCK inhibitor. In contrast, smooth muscles containing the T694A mutation showed a significant reduction of force along with reduced RLC phosphorylation. The contractile responses of T694A mutant smooth muscle were also independent of ROCK activation. Thus, phosphorylation of MYPT1 T694, but not T852, is a primary mechanism contributing to inhibition of MLCP activity and enhancement of RLC phosphorylation in vivo. The constitutive phosphorylation of MYPT1 T694 may provide a mechanism for regulating force maintenance of smooth muscle. Key points Force production and maintenance in smooth muscle is largely controlled by myosin regulatory light chain (RLC) phosphorylation, which relies on a balance between Ca2+/calmodulin-dependent myosin light chain kinase (MLCK) and myosin light chain phosphatase (MLCP) activities. MYPT1 is the regulatory subunit of MLCP that biochemically inhibits MLCP activity via T694 or T852 phosphorylation in vitro. Here we separately investigated the contribution of these two phosphorylation sites in bladder smooth muscles by establishing two single point mutation mouse lines, T694A and T852A, and found that phosphorylation of MYPT1 T694, but not T852, mediates force maintenance via inhibition of MLCP activity and enhancement of RLC phosphorylation in vivo. Our findings reveal the role of MYPT1 T694/T852 phosphorylation in vivo in regulation of smooth muscle contraction. PMID:25433069

In vivo roles for myosin phosphatase targeting subunit-1 phosphorylation sites T694 and T852 in bladder smooth muscle contraction.

PubMed

Chen, Cai-Ping; Chen, Xin; Qiao, Yan-Ning; Wang, Pei; He, Wei-Qi; Zhang, Cheng-Hai; Zhao, Wei; Gao, Yun-Qian; Chen, Chen; Tao, Tao; Sun, Jie; Wang, Ye; Gao, Ning; Kamm, Kristine E; Stull, James T; Zhu, Min-Sheng

2015-02-01

Force production and maintenance in smooth muscle is largely controlled by myosin regulatory light chain (RLC) phosphorylation, which relies on a balance between Ca(2+)/calmodulin-dependent myosin light chain kinase (MLCK) and myosin light chain phosphatase (MLCP) activities. MYPT1 is the regulatory subunit of MLCP that biochemically inhibits MLCP activity via T694 or T852 phosphorylation in vitro. Here we separately investigated the contribution of these two phosphorylation sites in bladder smooth muscles by establishing two single point mutation mouse lines, T694A and T852A, and found that phosphorylation of MYPT1 T694, but not T852, mediates force maintenance via inhibition of MLCP activity and enhancement of RLC phosphorylation in vivo. Our findings reveal the role of MYPT1 T694/T852 phosphorylation in vivo in regulation of smooth muscle contraction. Force production and maintenance in smooth muscle is largely controlled by different signalling modules that fine tune myosin regulatory light chain (RLC) phosphorylation, which relies on a balance between Ca(2+)/calmodulin-dependent myosin light chain kinase (MLCK) and myosin light chain phosphatase (MLCP) activities. To investigate the regulation of MLCP activity in vivo, we analysed the role of two phosphorylation sites on MYPT1 (regulatory subunit of MLCP) that biochemically inhibit MLCP activity in vitro. MYPT1 is constitutively phosphorylated at T694 by unidentified kinases in vivo, whereas the T852 site is phosphorylated by RhoA-associated protein kinase (ROCK). We established two mouse lines with alanine substitution of T694 or T852. Isolated bladder smooth muscle from T852A mice displayed no significant changes in RLC phosphorylation or force responses, but force was inhibited with a ROCK inhibitor. In contrast, smooth muscles containing the T694A mutation showed a significant reduction of force along with reduced RLC phosphorylation. The contractile responses of T694A mutant smooth muscle were also independent of ROCK activation. Thus, phosphorylation of MYPT1 T694, but not T852, is a primary mechanism contributing to inhibition of MLCP activity and enhancement of RLC phosphorylation in vivo. The constitutive phosphorylation of MYPT1 T694 may provide a mechanism for regulating force maintenance of smooth muscle. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Wotan’s Workshop: Military Experiments before World War II

DTIC Science & Technology

2013-06-27

photo: A column of mock tanks—with wood and canvas armor shapes mounted on light vehicles—participated in German military maneuvers in 1928. (Imperial...37mm antitank gun. The gunners called it a “ wood -o- meter” and claimed it could fire 400 splinters and 15 drops of turpentine per minute. Charles Gorry...ticipation in maneuvers. These surrogates, made of wood and canvas and mounted on cars or even on bicycles, were used in force-on-force maneuvers that

Light-induced yellowing of selectively 13C-enriched dehydrogenation polymers (DHPs). Part 1, Side-chain 13C-enriched DHP ([alpha], [beta], and [gamma]-13C)

Treesearch

Jim Parkas; Magnus Paulsson; Terashima Noritsugu; Ulla Westermark; Sally Ralph

2004-01-01

Light-induced yellowing has been studied using side-chain ([alpha], [beta], and [gamma]) 13C-enriched DHP (dehydrogenation polymer) and quantitative solution state 13C NMR spectroscopy. The DHP was formed from 13C-enriched coniferin using an enzymatic system consisting of [beta]-glucosidase, glucose oxidase, and peroxidase in a pH 6 buffer solution. The DHP was applied...

TCTEX1D4 Interactome in Human Testis: Unraveling the Function of Dynein Light Chain in Spermatozoa

PubMed Central

Freitas, Maria João; Korrodi-Gregório, Luís; Morais-Santos, Filipa; da Cruz e Silva, Edgar

2014-01-01

Abstract Studies were designed to identify the TCTEX1D4 interactome in human testis, with the purpose of unraveling putative protein complexes essential to male reproduction and thus novel TCTEX1D4 functions. TCTEX1D4 is a dynein light chain that belongs to the DYNT1/TCTEX1 family. In spermatozoa, it appears to be important to sperm motility, intraflagellar transport, and acrosome reaction. To contribute to the knowledge on TCTEX1D4 function in testis and spermatozoa, a yeast two-hybrid assay was performed in testis, which allowed the identification of 40 novel TCTEX1D4 interactors. Curiously, another dynein light chain, TCTEX1D2, was identified and its existence demonstrated for the first time in human spermatozoa. Immunofluorescence studies proved that TCTEX1D2 is an intra-acrosomal protein also present in the midpiece, suggesting a role in cargo movement in human spermatozoa. Further, an in silico profile of TCTEX1D4 revealed that most TCTEX1D4 interacting proteins were not previously characterized and the ones described present a very broad nature. This reinforces TCTEX1D4 as a dynein light chain that is capable of interacting with a variety of functionally different proteins. These observations collectively contribute to a deeper molecular understanding of the human spermatozoa function. PMID:24606217

Age- and Activity-Related Differences in the Abundance of Myosin Essential and Regulatory Light Chains in Human Muscle

PubMed Central

Cobley, James N.; Ab. Malik, Zulezwan; Morton, James P.; Close, Graeme L.; Edwards, Ben J.; Burniston, Jatin G.

2016-01-01

Traditional methods for phenotyping skeletal muscle (e.g., immunohistochemistry) are labor-intensive and ill-suited to multixplex analysis, i.e., assays must be performed in a series. Addressing these concerns represents a largely unmet research need but more comprehensive parallel analysis of myofibrillar proteins could advance knowledge regarding age- and activity-dependent changes in human muscle. We report a label-free, semi-automated and time efficient LC-MS proteomic workflow for phenotyping the myofibrillar proteome. Application of this workflow in old and young as well as trained and untrained human skeletal muscle yielded several novel observations that were subsequently verified by multiple reaction monitoring (MRM). We report novel data demonstrating that human ageing is associated with lesser myosin light chain 1 content and greater myosin light chain 3 content, consistent with an age-related reduction in type II muscle fibers. We also disambiguate conflicting data regarding myosin regulatory light chain, revealing that age-related changes in this protein more closely reflect physical activity status than ageing per se. This finding reinforces the need to control for physical activity levels when investigating the natural process of ageing. Taken together, our data confirm and extend knowledge regarding age- and activity-related phenotypes. In addition, the MRM transitions described here provide a methodological platform that can be fine-tuned to suite multiple research needs and thus advance myofibrillar phenotyping. PMID:28248225

Genome-wide association study of immunoglobulin light chain amyloidosis in three patient cohorts: comparison with myeloma.

PubMed

da Silva Filho, M I; Försti, A; Weinhold, N; Meziane, I; Campo, C; Huhn, S; Nickel, J; Hoffmann, P; Nöthen, M M; Jöckel, K-H; Landi, S; Mitchell, J S; Johnson, D; Morgan, G J; Houlston, R; Goldschmidt, H; Jauch, A; Milani, P; Merlini, G; Rowcieno, D; Hawkins, P; Hegenbart, U; Palladini, G; Wechalekar, A; Schönland, S O; Hemminki, K

2017-08-01

Immunoglobulin light chain (AL) amyloidosis is characterized by tissue deposition of amyloid fibers derived from immunoglobulin light chain. AL amyloidosis and multiple myeloma (MM) originate from monoclonal gammopathy of undetermined significance. We wanted to characterize germline susceptibility to AL amyloidosis using a genome-wide association study (GWAS) on 1229 AL amyloidosis patients from Germany, UK and Italy, and 7526 healthy local controls. For comparison with MM, recent GWAS data on 3790 cases were used. For AL amyloidosis, single nucleotide polymorphisms (SNPs) at 10 loci showed evidence of an association at P<10 -5 with homogeneity of results from the 3 sample sets; some of these were previously documented to influence MM risk, including the SNP at the IRF4 binding site. In AL amyloidosis, rs9344 at the splice site of cyclin D1, promoting translocation (11;14), reached the highest significance, P=7.80 × 10 -11 ; the SNP was only marginally significant in MM. SNP rs79419269 close to gene SMARCD3 involved in chromatin remodeling was also significant (P=5.2 × 10 -8 ). These data provide evidence for common genetic susceptibility to AL amyloidosis and MM. Cyclin D1 is a more prominent driver in AL amyloidosis than in MM, but the links to aggregation of light chains need to be demonstrated.

Surviving Surrogate Decision-Making: What Helps and Hampers the Experience of Making Medical Decisions for Others

PubMed Central

Starks, Helene; Taylor, Janelle S.; Hopley, Elizabeth K.; Fryer-Edwards, Kelly

2007-01-01

BACKGROUND A majority of end-of-life medical decisions are made by surrogate decision-makers who have varying degrees of preparation and comfort with their role. Having a seriously ill family member is stressful for surrogates. Moreover, most clinicians have had little training in working effectively with surrogates. OBJECTIVES To better understand the challenges of decision-making from the surrogate’s perspective. DESIGN Semistructured telephone interview study of the experience of surrogate decision-making. PARTICIPANTS Fifty designated surrogates with previous decision-making experience. APPROACH We asked surrogates to describe and reflect on their experience of making medical decisions for others. After coding transcripts, we conducted a content analysis to identify and categorize factors that made decision-making more or less difficult for surrogates. RESULTS Surrogates identified four types of factors: (1) surrogate characteristics and life circumstances (such as coping strategies and competing responsibilities), (2) surrogates’ social networks (such as intrafamily discord about the “right” decision), (3) surrogate–patient relationships and communication (such as difficulties with honoring known preferences), and (4) surrogate–clinician communication and relationship (such as interacting with a single physician whom the surrogate recognizes as the clinical spokesperson vs. many clinicians). CONCLUSIONS These data provide insights into the challenges that surrogates encounter when making decisions for loved ones and indicate areas where clinicians could intervene to facilitate the process of surrogate decision-making. Clinicians may want to include surrogates in advance care planning prior to decision-making, identify and address surrogate stressors during decision-making, and designate one person to communicate information about the patient’s condition, prognosis, and treatment options. PMID:17619223

Highly efficient conductivity modulation of cinnamate-based light-responsive ionic liquids in aqueous solutions.

PubMed

Yang, Jie; Wang, Huiyong; Wang, Jianji; Zhang, Yue; Guo, Zhongjia

2014-12-11

A new class of cinnamate-based light-responsive ionic liquids was synthesized and characterized, and these ionic liquids with longer alkyl chains showed a remarkable increase in ionic conductivity under UV light irradiation in aqueous solutions.

Investigating conflict in ICUs - Is the clinicians’ perspective enough?

PubMed Central

Schuster, Rachel A.; Hong, Seo Yeon; Arnold, Robert M.; White, Douglas B.

2013-01-01

Objective Most studies have assessed conflict between clinicians and surrogate decision makers in ICUs from only clinicians’ perspectives. It is unknown if surrogates’ perceptions differ from clinicians’. We sought to determine the degree of agreement between physicians and surrogates about conflict, and to identify predictors of physician-surrogate conflict. Design Prospective cohort study. Setting Four ICUs of two hospitals in San Francisco, California. Patients 230 surrogate decision makers and 100 physicians of 175 critically ill patients. Measurements Questionnaires addressing participants’ perceptions of whether there was physician-surrogate conflict, as well as attitudes and preferences about clinician-surrogate communication; kappa scores to quantify physician-surrogate concordance about the presence of conflict; and hierarchical multivariate modeling to determine predictors of conflict. Main Results Either the physician or surrogate identified conflict in 63% of cases. Physicians were less likely to perceive conflict than surrogates (27.8% vs 42.3%; p=0.007). Agreement between physicians and surrogates about conflict was poor (kappa = 0.14). Multivariable analysis with surrogate-assessed conflict as the outcome revealed that higher levels of surrogates’ satisfaction with physicians’ bedside manner were associated with lower odds of conflict (OR: 0.75 per 1 point increase in satisfaction, 95% CI 0.59–0.96). Multivariable analysis with physician-assessed conflict as the outcome revealed that the surrogate having felt discriminated against in the healthcare setting was associated with higher odds of conflict (OR 17.5, 95% CI 1.6–190.1) while surrogates’ satisfaction with physicians’ bedside manner was associated with lower odds of conflict (0–10 scale, OR 0.76 per 1 point increase, 95% CI 0.58–0.99). Conclusions Conflict between physicians and surrogates is common in ICUs. There is little agreement between physicians and surrogates about whether physician-surrogate conflict has occurred. Further work is needed to develop reliable and valid methods to assess conflict. In the interim, future studies should assess conflict from the perspective of both clinicians and surrogates. PMID:24434440

Novel Strategy for Photopatterning Emissive Polymer Brushes for Organic Light Emitting Diode Applications

PubMed Central

2017-01-01

A light-mediated methodology to grow patterned, emissive polymer brushes with micron feature resolution is reported and applied to organic light emitting diode (OLED) displays. Light is used for both initiator functionalization of indium tin oxide and subsequent atom transfer radical polymerization of methacrylate-based fluorescent and phosphorescent iridium monomers. The iridium centers play key roles in photocatalyzing and mediating polymer growth while also emitting light in the final OLED structure. The scope of the presented procedure enables the synthesis of a library of polymers with emissive colors spanning the visible spectrum where the dopant incorporation, position of brush growth, and brush thickness are readily controlled. The chain-ends of the polymer brushes remain intact, affording subsequent chain extension and formation of well-defined diblock architectures. This high level of structure and function control allows for the facile preparation of random ternary copolymers and red–green–blue arrays to yield white emission. PMID:28691078

Novel Strategy for Photopatterning Emissive Polymer Brushes for Organic Light Emitting Diode Applications.

PubMed

Page, Zachariah A; Narupai, Benjaporn; Pester, Christian W; Bou Zerdan, Raghida; Sokolov, Anatoliy; Laitar, David S; Mukhopadhyay, Sukrit; Sprague, Scott; McGrath, Alaina J; Kramer, John W; Trefonas, Peter; Hawker, Craig J

2017-06-28

A light-mediated methodology to grow patterned, emissive polymer brushes with micron feature resolution is reported and applied to organic light emitting diode (OLED) displays. Light is used for both initiator functionalization of indium tin oxide and subsequent atom transfer radical polymerization of methacrylate-based fluorescent and phosphorescent iridium monomers. The iridium centers play key roles in photocatalyzing and mediating polymer growth while also emitting light in the final OLED structure. The scope of the presented procedure enables the synthesis of a library of polymers with emissive colors spanning the visible spectrum where the dopant incorporation, position of brush growth, and brush thickness are readily controlled. The chain-ends of the polymer brushes remain intact, affording subsequent chain extension and formation of well-defined diblock architectures. This high level of structure and function control allows for the facile preparation of random ternary copolymers and red-green-blue arrays to yield white emission.

Association of immunoglobulin G4 and free light chain with idiopathic pleural effusion.

PubMed

Murata, Y; Aoe, K; Mimura-Kimura, Y; Murakami, T; Oishi, K; Matsumoto, T; Ueoka, H; Matsunaga, K; Yano, M; Mimura, Y

2017-10-01

The cause of pleural effusion remains uncertain in approximately 15% of patients despite exhaustive evaluation. As recently described immunoglobulin (Ig)G4-related disease is a fibroinflammatory disorder that can affect various organs, including the lungs, we investigate whether idiopathic pleural effusion includes IgG4-associated etiology. Between 2000 and 2012, we collected 830 pleural fluid samples and reviewed 35 patients with pleural effusions undiagnosed after pleural biopsy at Yamaguchi-Ube Medical Center. Importantly, IgG4 immunostaining revealed infiltration of IgG4-positive plasma cells in the pleura of 12 patients (34%, IgG4 + group). The median effusion IgG4 level was 41 mg/dl in the IgG4 + group and 27 mg/dl in the IgG4 - group (P < 0·01). The light and heavy chains of effusion IgG4 antibodies of patients in the IgG4 + group were heterogeneous by two-dimensional electrophoresis, indicating the absence of clonality of the IgG4 antibodies. Interestingly, the κ light chains were more heterogeneous than the λ light chains. The measurement of the κ and λ free light chain (FLC) levels in the pleural fluids showed significantly different κ FLC levels (median: 28·0 versus 9·1 mg/dl, P < 0·01) and κ/λ ratios (median: 2·0 versus 1·2, P < 0·001) between the IgG4 + and IgG4 - groups. Furthermore, the κ/λ ratios were correlated with the IgG4 + /IgG + plasma cell ratios in the pleura of the IgG4 + group. Taken together, these results demonstrate the involvement of IgG4 in certain idiopathic pleural effusions and provide insights into the diagnosis, pathogenesis and therapeutic opportunities of IgG4-associated pleural effusion. © 2017 British Society for Immunology.

Matrix Metalloproteinases and their Tissue Inhibitors in Cardiac Amyloidosis: Relationship to Structural, Functional Myocardial Changes and to Light Chain Amyloid Deposition

PubMed Central

Biolo, Andreia; Ramamurthy, Sujata; Connors, Lawreen H.; O'Hara, Carl J.; Meier-Ewert, Hans K.; Hoo, Pamela T. Soo; Sawyer, Douglas B.; Seldin, David S.; Sam, Flora

2009-01-01

Background Cardiac amyloidosis is characterized by amyloid infiltration resulting in extracellular matrix (ECM) disruption. Amyloid cardiomyopathy due to immunoglobulin light chain protein (AL-CMP) deposition, has an accelerated clinical course and a worse prognosis compared to non-light chain cardiac amyloidoses i.e., forms associated with wild-type or mutated transthyretin (TTR). We therefore tested the hypothesis that determinants of proteolytic activity of the ECM, the matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), would have distinct patterns and contribute to the pathogenesis of AL-CMP vs. TTR. Methods / Results We studied 40 patients with systemic amyloidosis: 10 AL-CMP patients, 20 patients with TTR-associated forms of cardiac amyloidosis, i.e. senile systemic amyloidois (SSA, involving wild-type TTR) or mutant TTR (ATTR), and 10 patients with AL amyloidosis without cardiac involvement. Serum MMP-2 and −9, TIMP-1, −2 and −4, brain natriuretic peptide (BNP) values and echocardiography were determined. AL-CMP and SSA-ATTR groups had similar degrees of increased left ventricular wall thickness (LVWT). However, BNP, MMP-9 and TIMP-1 levels were distinctly elevated accompanied by marked diastolic dysfunction in the AL-CMP group vs. no or minimal increases in the SSA-ATTR group. BNP, MMPs and TIMPs were not correlated with the degree of LVWT but were correlated to each other and to measures of diastolic dysfunction. Immunostaining of human endomyocardial biopsies showed diffuse expression of MMP-9 and TIMP-1 in AL-CMP and limited expression in SSA or ATTR hearts. Conclusions Despite comparable LVWT with TTR-related cardiac amyloidosis, AL-CMP patients have higher BNP, MMPs and TIMPs, which correlated with diastolic dysfunction. These findings suggest a relationship between light chains and ECM proteolytic activation that may play an important role in the functional and clinical manifestations of AL-CMP, distinct from the other non-light chain cardiac amyloidoses. PMID:19808299

Site-directed Mutagenesis Reveals Regions Implicated in the Stability and Fiber Formation of Human λ3r Light Chains

DOE PAGES

Villalba, Miryam I.; Canul-Tec, Juan C.; Luna-Martínez, Oscar D.; ...

2014-12-11

Light chain amyloidosis (AL) is a disease that affects vital organs by the fibrillar aggregation of monoclonal light chains. λ3r germ line is significantly implicated in this disease. In this paper, we contrasted the thermodynamic stability and aggregation propensity of 3mJL2 (nonamyloidogenic) and 3rJL2 (amyloidogenic) λ3 germ lines. Because of an inherent limitation (extremely low expression), Cys at position 34 of the 3r germ line was replaced by Tyr reaching a good expression yield. A second substitution (W91A) was introduced in 3r to obtain a better template to incorporate additional mutations. Although the single mutant (C34Y) was not fibrillogenic, themore » second mutation located at CDR3 (W91A) induced fibrillogenesis. We propose, for the first time, that CDR3 (position 91) affects the stability and fiber formation of human λ3r light chains. Using the double mutant (3rJL2/YA) as template, other variants were constructed to evaluate the importance of those substitutions into the stability and aggregation propensity of λ3 light chains. A change in position 7 (P7D) boosted 3rJL2/YA fibrillogenic properties. Modification of position 48 (I48M) partially reverted 3rJL2/YA fibril aggregation. Finally, changes at positions 8 (P8S) or 40 (P40S) completely reverted fibril formation. These results confirm the influential roles of N-terminal region (positions 7 and 8) and the loop 40–60 (positions 40 and 48) on AL. X-ray crystallography revealed that the three-dimensional topology of the single and double λ3r mutants was not significantly altered. Finally, this mutagenic approach helped to identify key regions implicated in λ3 AL.« less

Immunoglobulin derived depositions in the nervous system: novel mass spectrometry application for protein characterization in formalin-fixed tissues.

PubMed

Rodriguez, Fausto J; Gamez, Jeffrey D; Vrana, Julie A; Theis, Jason D; Giannini, Caterina; Scheithauer, Bernd W; Parisi, Joseph E; Lucchinetti, Claudia F; Pendlebury, William W; Bergen, H Robert; Dogan, Ahmet

2008-10-01

Proteinaceous deposits are occasionally encountered in surgically obtained biopsies of the nervous system. Some of these are amyloidomas, although the precise nature of other cases remains uncertain. We studied 13 cases of proteinaceous aggregates in clinical specimens of the nervous system. Proteins contained within laser microdissected areas of interest were identified from tryptic peptide sequences by liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS). Immunohistochemical studies for immunoglobulin heavy and light chains and amyloidogenic proteins were performed in all cases. Histologically, the cases were classified into three groups: 'proteinaceous deposit not otherwise specified' (PDNOS) (n=6), amyloidoma (n=5), or 'intracellular crystals' (n=2). LC-MS/MS demonstrated the presence of lambda, but not kappa, light chain as well as serum amyloid P in all amyloidomas. lambda-Light-chain immunostaining was noted in amyloid (n=5), although demonstrable monotypic lymphoplasmacytic cells were seen in only one case. Conversely, in PDNOS kappa, but not lambda, was evident in five cases, both light chains being present in a single case. In three cases of PDNOS, a low-grade B-cell lymphoma consistent with marginal zone lymphoma was present in the brain specimen (n=2) or spleen (n=1). Lastly, in the 'intracellular crystals' group, the crystals were present within CD68+ macrophages in one case wherein kappa-light chain was found by LC-MS/MS only; the pathology was consistent with crystal-storing histiocytosis. In the second case, the crystals contained immunoglobulin G within CD138+ plasma cells. Our results show that proteinaceous deposits in the nervous system contain immunoglobulin components and LC-MS/MS accurately identifies the content of these deposits in clinical biopsy specimens. LC-MS/MS represents a novel application for characterization of these deposits and is of diagnostic utility in addition to standard immunohistochemical analyses.

Tertiary structure of human {Lambda}6 light chains.

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

Pokkuluri, P. R.; Solomon, A.; Weiss, D. T.

1999-01-01

AL amyloidosis is a disease process characterized by the pathologic deposition of monoclonal light chains in tissue. To date, only limited information has been obtained on the molecular features that render such light chains amyloidogenic. Although protein products of the major human V kappa and V lambda gene families have been identified in AL deposits, one particular subgroup--lambda 6--has been found to be preferentially associated with this disease. Notably, the variable region of lambda 6 proteins (V lambda 6) has distinctive primary structural features including the presence in the third framework region (FR3) of two additional amino acid residues thatmore » distinguish members of this subgroup from other types of light chains. However, the structural consequences of these alterations have not been elucidated. To determine if lambda 6 proteins possess unique tertiary structural features, as compared to light chains of other V lambda subgroups, we have obtained x-ray diffraction data on crystals prepared from two recombinant V lambda 6 molecules. These components, isolated from a bacterial expression system, were generated from lambda 6-related cDNAs cloned from bone marrow-derived plasma cells from a patient (Wil) who had documented AL amyloidosis and another (Jto) with multiple myeloma and tubular cast nephropathy, but no evident fibrillar deposits. The x-ray crystallographic analyses revealed that the two-residue insertion located between positions 68 and 69 (not between 66 and 67 as previously surmised) extended an existing loop region that effectively increased the surface area adjacent to the first complementarity determining region (CDR1). Further, an unusual interaction between the Arg 25 and Phe 2 residues commonly found in lambda 6 molecules was noted. However, the structures of V lambda 6 Wil and Jto also differed from each other, as evidenced by the presence in the latter of certain ionic and hydrophobic interactions that we posit increased protein stability and thus prevented amyloid formation.« less

Diffuse Peritoneal and Bowel Wall Infiltration by Light Chain-AL Amyloidosis with Omental Calcification Mimicking Abdominal Carcinomatosis - An Elderly Female with Incidental Finding of Light Chain Monoclonal Gammopathy of Undetermined Significance (LC-MGUS).

PubMed

Junejo, Shoaib; Ali, Yasir; Singh Lubana, Sandeep; Tuli, Sandeep S

2017-11-25

BACKGROUND Amyloidosis is the extracellular tissue deposition of plasma proteins, which after conformational changes, forms antiparallel beta pleated sheets of fibrils. Amyloid light-chain (AL) is a type of amyloidosis that is due to deposition of proteins derived from immunoglobulin (Ig) light chains. Gastrointestinal tract (GIT) involvement most often found in amyloid A (AA) amyloidosis type. There have been no reports of obstructive GIT AL amyloid patients having monoclonal gammopathy of undetermined significance (MGUS). Our case is the first case to show two coinciding conditions; one is the association of GIT AL amyloidosis with the incidental finding of a rare type of MGUS (LC-MGUS) and the other is the radiologic presentation of GIT amyloidosis with omental calcification mimicking the GIT malignancy. CASE REPORT A 68-year-old female presented with symptoms of partial bowel obstruction, including intermittent diffuse abdominal pain and constipation. After computed tomography (CT) abdomen and pelvis, an exploratory laparotomy was needed because of suspicion of abdominal carcinomatosis due to diffuse omental calcification. The tissue sent for biopsy surprisingly showed AL amyloidosis. The patient did not report any systemic symptoms. Further workup was advised to inquire about the plasma cell dyscrasia which eventually turned into a very rare version of MGUS knows as light chain MGUS (LC-MGUS). Following adequate resection of the involved structures, the patient was then placed on chemotherapy and successfully went into remission. CONCLUSIONS This case report illustrates that in an era of evidence based medicine, it is important to show through case reports the association of GIT AL amyloidosis with LC-MGUS, as the literature on this topic is lacking. It also points to the importance of timely intervention that can greatly enhance, not only the only the chances of remission but also prevention of further complications such as malignant transformation.

Heterogeneous and monoclonal helper T cells induce similar anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) antibody populations in the primary adoptive response. II. Lambda light chain dominance and idiotope expression.

PubMed

Smith, F I; Tesch, H; Rajewsky, K

1984-02-01

When the hapten (4-hydroxy-3-nitrophenyl)acetyl (NP) is presented on different carrier molecules, different anti-NP antibody responses are stimulated. On stimulation with NP-lipopolysaccharide (LPS) [T-independent type 1 (TI-1) antigen] kappa + antibodies are the major population, whereas on stimulation with NP-Ficoll [T-independent type 2 (TI-2) antigen], NP-keyhole limpet hemocyanin (KLH) or NP-chicken gamma globulin (CG) [T-dependent (TD) antigens], lambda 1+ antibodies dominate. The relative contribution of idiotopes Ac38 or Ac146 to the lambda 1+ anti-NP response was also different on comparison of TI-1 with TI-2 or TD anti-NP responses. We investigated whether light chain- or idiotype-specific T cells are responsible for these differences. Analysis of the anti-NP response of nude mice after immunization with NP-Ficoll showed lambda 1 dominance. Likewise primary adoptive transfer experiments using carrier-specific T cell lines to reconstitute the TD anti-NP response to NP-KLH or NP-CG, showed that help from carrier-specific T cells alone is capable of stimulating the characteristic lambda 1 dominant response. No significant difference could be found in the levels of Ac38 and Ac146 idiotope expression between mice reconstituted with splenic T cells and those reconstituted with T cell lines. These results suggest that light chain- or idiotype-specific T cells are required neither for the production of lambda 1 light chain dominance, nor for the appearance of idiotopes characteristic of the primary anti-NP response. The possible reasons for differences seen in both light chain and idiotope expression between primary anti-NP responses to the TI-1 antigen NP-LPS and those to TD or TI-2 antigens are discussed.

A Surrogate Approach to the Experimental Optimization of Multielement Airfoils

NASA Technical Reports Server (NTRS)

Otto, John C.; Landman, Drew; Patera, Anthony T.

1996-01-01

The incorporation of experimental test data into the optimization process is accomplished through the use of Bayesian-validated surrogates. In the surrogate approach, a surrogate for the experiment (e.g., a response surface) serves in the optimization process. The validation step of the framework provides a qualitative assessment of the surrogate quality, and bounds the surrogate-for-experiment error on designs "near" surrogate-predicted optimal designs. The utility of the framework is demonstrated through its application to the experimental selection of the trailing edge ap position to achieve a design lift coefficient for a three-element airfoil.

When life imitates art: surrogate decision making at the end of life.

PubMed

Shapiro, Susan P

2007-01-01

The privileging of the substituted judgment standard as the gold standard for surrogate decision making in law and bioethics has constrained the research agenda in end-of-life decision making. The empirical literature is inundated with a plethora of "Newlywed Game" designs, in which potential patients and potential surrogates respond to hypothetical scenarios to see how often they "get it right." The preoccupation with determining the capacity of surrogates to accurately reproduce the judgments of another makes a number of assumptions that blind scholars to the variables central to understanding how surrogates actually make medical decisions on behalf of another. These assumptions include that patient preferences are knowable, surrogates have adequate and accurate information, time stands still, patients get the surrogates they want, patients want and surrogates utilize substituted judgment criteria, and surrogates are disinterested. This article examines these assumptions and considers the challenges of designing research that makes them problematic.

The psychological well-being and prenatal bonding of gestational surrogates.

PubMed

Lamba, N; Jadva, V; Kadam, K; Golombok, S

2018-02-23

How does the psychological well-being and prenatal bonding of Indian surrogates differ from a comparison group of mothers? Surrogates had higher levels of depression during pregnancy and post-birth, displayed lower emotional connection with the unborn baby, and greater care towards the healthy growth of the foetus, than the comparison group of mothers. Studies in the West have found that surrogates do not suffer long-term psychological harm. One study has shown that surrogates bond less with the foetus than expectant mothers. This study uses a prospective, longitudinal and cross-sectional design. Surrogates and a matched group of expectant mothers were seen twice, during 4-9 months of pregnancy and 4-6 months after the birth. Semi-structured interviews and standardized questionnaires were administered to 50 surrogates and 69 expectant mothers during pregnancy and 45 surrogates and 49 expectant mothers post-birth. All gestational surrogates were hosting pregnancies for international intended parents. Surrogates had higher levels of depression compared to the comparison group of mothers, during pregnancy and post-birth (P < 0.02). Low social support during pregnancy, hiding surrogacy and criticism from others were found to be predictive of higher depression in surrogates post-birth (P < 0.05). Regarding prenatal bonding, surrogates interacted less with and thought less about the foetus but adopted better eating habits and were more likely to avoid unhealthy practices during pregnancy, than expectant mothers (P < 0.05). No associations were found between greater prenatal bonding and greater psychological distress during pregnancy or after relinquishment. All surrogates were recruited from one clinic in Mumbai, and thus the representativeness of this sample is not known. Also, the possibility of socially desirable responding from surrogates cannot be ruled out. As this is the first study of the psychological well-being of surrogates in low-income countries, the findings have important policy implications. Providing support and counselling to surrogates, especially during pregnancy, may alleviate some of the psychological problems faced by surrogates. This study was supported by the Wellcome Trust [097857/Z/11/Z] and Nehru Trust, Cambridge. K.K. is the Medical Director of Corion Fertility Clinic. All other authors have no conflict of interest to declare.

A molecular model for cocaine binding by the immunotherapeutic human/mouse chimeric monoclonal antibody 2E2.

PubMed

Lape, Michael; Paula, Stefan; Ball, William J

2010-06-01

Immunotherapy by cocaine-binding monoclonal antibodies (mAbs) has emerged as a promising strategy for the treatment of cocaine addiction. The human (gamma1 heavy chain)/murine (lambda light chain) chimeric mAb 2E2 has excellent affinity and specificity for cocaine and recent animal studies have demonstrated 2E2's ability in vivo to reduce cocaine levels in the brain as well as alter cocaine self-administration behavior in rats. In this study, we used mAb 2E2 amino acid sequence information to create a homology model for the 3-D structure of its Fv fragment. Subsequent computational docking studies revealed the intermolecular interactions potentially responsible for mAb 2E2's cocaine binding properties. The driving force of cocaine binding was identified as a combination of hydrophobic interactions and a single hydrogen bond between a light chain tyrosine residue and a carbonyl oxygen atom of cocaine. The model also allowed for an in silico evaluation of single/double residue mutations in the heavy and light chain variable regions that might further enhance mAb 2E2's cocaine binding properties. Copyright (c) 2010 Elsevier Masson SAS. All rights reserved.

A Molecular Model for Cocaine Binding by the Immunotherapeutic Human/Mouse Chimeric Monoclonal Antibody 2E2

PubMed Central

Lape, Michael; Paula, Stefan; Ball, William J.

2010-01-01

Immunotherapy by cocaine-binding monoclonal antibodies (mAbs) has emerged as a promising strategy for the treatment of cocaine addiction. The human (γ1 heavy chain)/murine (λ light chain) chimeric mAb 2E2 has excellent affinity and specificity for cocaine and recent animal studies have demonstrated 2E2’s ability in vivo to reduce cocaine levels in the brain as well as alter cocaine self-administration behavior in rats. In this study, we used mAb 2E2 amino acid sequence information to create a homology model for the 3-D structure of its Fv fragment. Subsequent computational docking studies revealed the intermolecular interactions potentially responsible for mAb 2E2’s cocaine binding properties. The driving force of cocaine binding was identified as a combination of hydrophobic interactions and a single hydrogen bond between a light chain tyrosine residue and a carbonyl oxygen atom of cocaine. The model also allowed for an in silico evaluation of single/double residue mutations in the heavy and light chain variable regions that might further enhance mAb 2E2’s cocaine binding properties. PMID:20185210

Oxidative Post-Translational Modifications of an Amyloidogenic Immunoglobulin Light Chain Protein.

PubMed

Lu, Yanyan; Jiang, Yan; Prokaeva, Tatiana; Connors, Lawreen H; Costello, Catherine E

2017-05-01

Immunoglobulin light chain amyloidosis (AL) is a plasma cell disorder characterized by overproduction and deposition of monoclonal immunoglobulin (Ig) light chains (LC) or variable region fragments as amyloid fibrils in various organs and tissues. Much clinical evidence indicates that patients with AL amyloidosis sustain cardiomyocyte impairment and suffer from oxidative stress. We seek to understand the underlying biochemical pathways whose disruption or amplification during sporadic or sustained disease states leads to harmful physiological consequences and to determine the detailed structures of intermediates and products that serve as signposts for the biochemical changes and represent potential biomarkers. In this study, matrix-assisted laser desorption/ionization mass spectrometry provided extensive evidence for oxidative post-translational modifications (PTMs) of an amyloidogenic Ig LC protein from a patient with AL amyloidosis. Some of the tyrosine residues were heavily mono- or di-chlorinated. In addition, a novel oxidative conversion to a nitrile moiety was observed for many of the terminal aminomethyl groups on lysine side chains. In vitro experiments using model peptides, in-solution oxidation, and click chemistry demonstrated that hypochlorous acid produced by the myeloperoxidase - hydrogen peroxide - chloride system could be responsible for these and other, more commonly observed modifications.

Terminations of DNA synthesis on 'proflavine and light'-treated phi X174 single-stranded DNA.

PubMed

Piette, J; Calberg-Bacq, C M; Lopez, M; van de Vorst, A

1984-04-05

Bacteriophage phi X174 single-stranded DNA molecules were primed with five different restriction fragments and irradiated with visible light in the presence of proflavine. This photodamaged DNA was used as template for the in vitro complementary chain synthesis by E. coli DNA polymerase I (Klenow fragment). Chain terminations were observed by polyacrylamide gel electrophoresis of the synthesized products and localized by comparison with standard sequencing performed simultaneously on the untreated template. 90% of the chain terminations occurred one nucleotide before a guanine residue in the template strand. More than 80% of the sequenced guanine residues were blocking lesions demonstrating the absence of 'hot-spots' for the photodamaging effect of proflavine. At a defined position, the chain termination frequency increased linearly with the irradiation time and was directly influenced by the proflavine concentration present. An important part of lesions resulted from the action of singlet oxygen produced by excited proflavine as shown by the effect that both NaN3 and 2H2O exerted on the reaction. The induced blocking lesions must be important in vivo since no complete replicative forms could be extracted from cell infected with bacteriophages inactivated by 'proflavine and light' treatment.

Primary ciliary dyskinesia caused by homozygous mutation in DNAL1, encoding dynein light chain 1.

PubMed

Mazor, Masha; Alkrinawi, Soliman; Chalifa-Caspi, Vered; Manor, Esther; Sheffield, Val C; Aviram, Micha; Parvari, Ruti

2011-05-13

In primary ciliary dyskinesia (PCD), genetic defects affecting motility of cilia and flagella cause chronic destructive airway disease, randomization of left-right body asymmetry, and, frequently, male infertility. The most frequent defects involve outer and inner dynein arms (ODAs and IDAs) that are large multiprotein complexes responsible for cilia-beat generation and regulation, respectively. Although it has long been suspected that mutations in DNAL1 encoding the ODA light chain1 might cause PCD such mutations were not found. We demonstrate here that a homozygous point mutation in this gene is associated with PCD with absent or markedly shortened ODA. The mutation (NM_031427.3: c.449A>G; p.Asn150Ser) changes the Asn at position150, which is critical for the proper tight turn between the β strand and the α helix of the leucine-rich repeat in the hydrophobic face that connects to the dynein heavy chain. The mutation reduces the stability of the axonemal dynein light chain 1 and damages its interactions with dynein heavy chain and with tubulin. This study adds another important component to understanding the types of mutations that cause PCD and provides clinical information regarding a specific mutation in a gene not yet known to be associated with PCD. Copyright © 2011 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Poliomyelitis: immunoglobulin-containing cells in the central nervous system in acute and convalescent phases of the human disease.

PubMed Central

Esiri, M M

1980-01-01

The immunoperoxidase method has been used to demonstrate the presence of immunoglobulin-containing cells in the central nervous system in acute and convalescent phases of poliomyelitis. These cells were found in considerable numbers in the areas of damage during the acute phase, and persisted at the same sites, though in smaller numbers, during the convalescent phase for at least 8 months. Most of the positively stained cells were plasma cells. IgA was the commonest heavy chain type demonstrated, with lesser amounts also of IgG and, during the acute phase, IgM. In the acute phase more lambda than kappa light chain was demonstrated but in the convalescent phase this ratio was reversed. More light chain than heavy chain was demonstrable during the acute phase. The significance of these results is briefly discussed. Images Fig. 2 PMID:6771081

A Novel, In-solution Separation of Endogenous Cardiac Sarcomeric Proteins and Identification of Distinct Charged Variants of Regulatory Light Chain*

PubMed Central

Scruggs, Sarah B.; Reisdorph, Rick; Armstrong, Mike L.; Warren, Chad M.; Reisdorph, Nichole; Solaro, R. John; Buttrick, Peter M.

2010-01-01

The molecular conformation of the cardiac myosin motor is modulated by intermolecular interactions among the heavy chain, the light chains, myosin binding protein-C, and titin and is governed by post-translational modifications (PTMs). In-gel digestion followed by LC/MS/MS has classically been applied to identify cardiac sarcomeric PTMs; however, this approach is limited by protein size, pI, and difficulties in peptide extraction. We report a solution-based work flow for global separation of endogenous cardiac sarcomeric proteins with a focus on the regulatory light chain (RLC) in which specific sites of phosphorylation have been unclear. Subcellular fractionation followed by OFFGEL electrophoresis resulted in isolation of endogenous charge variants of sarcomeric proteins, including regulatory and essential light chains, myosin heavy chain, and myosin-binding protein-C of the thick filament. Further purification of RLC using reverse-phase HPLC separation and UV detection enriched for RLC PTMs at the intact protein level and provided a stoichiometric and quantitative assessment of endogenous RLC charge variants. Digestion and subsequent LC/MS/MS unequivocally identified that the endogenous charge variants of cardiac RLC focused in unique OFFGEL electrophoresis fractions were unphosphorylated (78.8%), singly phosphorylated (18.1%), and doubly phosphorylated (3.1%) RLC. The novel aspects of this study are that 1) milligram amounts of endogenous cardiac sarcomeric subproteome were focused with resolution comparable with two-dimensional electrophoresis, 2) separation and quantification of post-translationally modified variants were achieved at the intact protein level, 3) separation of intact high molecular weight thick filament proteins was achieved in solution, and 4) endogenous charge variants of RLC were separated; a novel doubly phosphorylated form was identified in mouse, and singly phosphorylated, singly deamidated, and deamidated/phosphorylated forms were identified and quantified in human non-failing and failing heart samples, thus demonstrating the clinical utility of the method. PMID:20445002

Therapeutic Approaches for Botulinum Intoxication Targeting Degradation of the Light Chain

DTIC Science & Technology

2014-06-01

protein and producing adequate amounts for in vitro testing. 15. SUBJECT TERMS- Botulinum toxin , ubiquitin, chimeric toxin light chains, LcA, LcE...that confer stability to LCs of botulinum toxin can be assessed by mutation of dileucine residues and systematic deletion of residues from LcA-LcE...cells. So What? Currently, there is no cure for botulinum poisoning once the toxin has entered a neuron. Moreover, the half-life of BoNT/A is very

Virtual medicinal chemistry: in silico pre-docking functional group transformation for discovery of novel inhibitors of botulinum toxin serotype A light chain.

PubMed

O'Malley, Sean; Sareth, Sina; Jiao, Guan-Sheng; Kim, Seongjin; Thai, April; Cregar-Hernandez, Lynne; McKasson, Linda; Margosiak, Stephen A; Johnson, Alan T

2013-05-01

A novel method for applying high-throughput docking to challenging metalloenzyme targets is described. The method utilizes information-based virtual transformation of library carboxylates to hydroxamic acids prior to docking, followed by compound acquisition, one-pot (two steps) chemical synthesis and in vitro screening. In two experiments targeting the botulinum neurotoxin serotype A metalloprotease light chain, hit rates of 32% and 18% were observed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Initiator and Photocatalyst-Free Visible Light Induced One-Pot Reaction: Concurrent RAFT Polymerization and CuAAC Click Reaction.

PubMed

Wang, Jie; Wang, Xinbo; Xue, Wentao; Chen, Gaojian; Zhang, Weidong; Zhu, Xiulin

2016-05-01

A new, visible light-catalyzed, one-pot and one-step reaction is successfully employed to design well-controlled side-chain functionalized polymers, by the combination of ambient temperature revisible addtion-fragmentation chain transfer (RAFT) polymerization and click chemistry. Polymerizations are well controlled in a living way under the irradiation of visible light-emitting diode (LED) light without photocatalyst and initiator, using the trithiocarbonate agent as iniferter (initiator-transfer agent-terminator) agent at ambient temperature. Fourier transfer infrared spectroscopy (FT-IR), NMR, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) data confirm the successful one-pot reaction. Compared to the reported zero-valent metal-catalyzed one-pot reaction, the polymerization rate is much faster than that of the click reaction, and the visible light-catalyzed one-pot reaction can be freely and easily regulated by turning on and off the light. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interactions of a potent cyclic peptide inhibitor with the light chain of botulinum neurotoxin A: Insights from X-ray crystallography.

PubMed

Kumaran, Desigan; Adler, Michael; Levit, Matthew; Krebs, Michael; Sweeney, Richard; Swaminathan, Subramanyam

2015-11-15

The seven antigenically distinct serotypes (A-G) of botulinum neurotoxin (BoNT) are responsible for the deadly disease botulism. BoNT serotype A (BoNT/A) exerts its lethal action by cleaving the SNARE protein SNAP-25, leading to inhibition of neurotransmitter release, flaccid paralysis and autonomic dysfunction. BoNTs are dichain proteins consisting of a ∼ 100 kDa heavy chain and a ∼ 50 kDa light chain; the former is responsible for neurospecific binding, internalization and translocation, and the latter for cleavage of neuronal SNARE proteins. Because of their extreme toxicity and history of weaponization, the BoNTs are regarded as potential biowarfare/bioterrorism agents. No post-symptomatic therapeutic interventions are available for BoNT intoxication other than intensive care; therefore it is imperative to develop specific antidotes against this neurotoxin. To this end, a cyclic peptide inhibitor (CPI-1) was evaluated in a FRET assay for its ability to inhibit BoNT/A light chain (Balc). CPI was found to be highly potent, exhibiting a Ki of 12.3 nM with full-length Balc448 and 39.2 nM using a truncated crystallizable form of the light chain (Balc424). Cocrystallization studies revealed that in the Balc424-CPI-1 complex, the inhibitor adopts a helical conformation, occupies a high percentage of the active site cavity and interacts in an amphipathic manner with critical active site residues. The data suggest that CPI-1 prevents SNAP-25 from accessing the Balc active site by blocking both the substrate binding path at the surface and the Zn(2+) binding region involved in catalysis. This differs from linear peptide inhibitors described to date which block only the latter. Published by Elsevier Ltd.

A natively paired antibody library yields drug leads with higher sensitivity and specificity than a randomly paired antibody library.

PubMed

Adler, Adam S; Bedinger, Daniel; Adams, Matthew S; Asensio, Michael A; Edgar, Robert C; Leong, Renee; Leong, Jackson; Mizrahi, Rena A; Spindler, Matthew J; Bandi, Srinivasa Rao; Huang, Haichun; Tawde, Pallavi; Brams, Peter; Johnson, David S

2018-04-01

Deep sequencing and single-chain variable fragment (scFv) yeast display methods are becoming more popular for discovery of therapeutic antibody candidates in mouse B cell repertoires. In this study, we compare a deep sequencing and scFv display method that retains native heavy and light chain pairing with a related method that randomly pairs heavy and light chain. We performed the studies in a humanized mouse, using interleukin 21 receptor (IL-21R) as a test immunogen. We identified 44 high-affinity binder scFv with the native pairing method and 100 high-affinity binder scFv with the random pairing method. 30% of the natively paired scFv binders were also discovered with the randomly paired method, and 13% of the randomly paired binders were also discovered with the natively paired method. Additionally, 33% of the scFv binders discovered only in the randomly paired library were initially present in the natively paired pre-sort library. Thus, a significant proportion of "randomly paired" scFv were actually natively paired. We synthesized and produced 46 of the candidates as full-length antibodies and subjected them to a panel of binding assays to characterize their therapeutic potential. 87% of the antibodies were verified as binding IL-21R by at least one assay. We found that antibodies with native light chains were more likely to bind IL-21R than antibodies with non-native light chains, suggesting a higher false positive rate for antibodies from the randomly paired library. Additionally, the randomly paired method failed to identify nearly half of the true natively paired binders, suggesting a higher false negative rate. We conclude that natively paired libraries have critical advantages in sensitivity and specificity for antibody discovery programs.

Interactions of a potent cyclic peptide inhibitor with the light chain of botulinum neurotoxin A: insights from x-ray crystallography

DOE PAGES

Kumaran, D.; Adler, M.; Levit, M.; ...

2015-10-17

The seven antigenically distinct serotypes (A to G) of botulinum neurotoxin (BoNT) are responsible for the deadly disease botulism. BoNT serotype A (BoNT/A) exerts its lethal action by cleaving the SNARE protein SNAP-25, leading to inhibition of neurotransmitter release, flaccid paralysis and autonomic dysfunction. BoNTs are dichain proteins: the heavy chain is responsible for neurospecific binding, internalization and translocation, and the light chain is responsible for substrate cleavage. Because of their extreme toxicity and prior history of weaponization, the BoNTs are considered to be potential bioterrorism agents. No post-symptomatic therapeutic interventions are available for BoNT intoxication other than critical care;more » therefore it is imperative to develop specific antidotes against this neurotoxin. To this end, a cyclic peptide inhibitor (CPI-1) was synthesized and found to inhibit BoNT/A light chain (Balc) with high affinity. When tested in a cell-free Förster resonance excitation transfer (FRET) assay, CPI-1 was found to have a K i of 13.9 nM using full-length Balc448 and 42.1 nM using a truncated crystallizable form of light chain (Balc424). Co-crystallization of CPI-1 with Balc424 revealed that in the Balc-CPI-1 complex, the inhibitor adopts a helical conformation, occupies a high percentage of the active site cavity and interacts in an amphipathic manner with critical active site residues. The data suggest that CPI-1 prevents SNAP-25 from accessing the Balc active site by blocking both the substrate binding path at the surface and the Zn 2+ binding region involved in catalysis. This is in contrast to linear peptide inhibitors described to date which block only the latter« less

A natively paired antibody library yields drug leads with higher sensitivity and specificity than a randomly paired antibody library

PubMed Central

Adler, Adam S.; Bedinger, Daniel; Adams, Matthew S.; Asensio, Michael A.; Edgar, Robert C.; Leong, Renee; Leong, Jackson; Mizrahi, Rena A.; Spindler, Matthew J.; Bandi, Srinivasa Rao; Huang, Haichun; Brams, Peter; Johnson, David S.

2018-01-01

ABSTRACT Deep sequencing and single-chain variable fragment (scFv) yeast display methods are becoming more popular for discovery of therapeutic antibody candidates in mouse B cell repertoires. In this study, we compare a deep sequencing and scFv display method that retains native heavy and light chain pairing with a related method that randomly pairs heavy and light chain. We performed the studies in a humanized mouse, using interleukin 21 receptor (IL-21R) as a test immunogen. We identified 44 high-affinity binder scFv with the native pairing method and 100 high-affinity binder scFv with the random pairing method. 30% of the natively paired scFv binders were also discovered with the randomly paired method, and 13% of the randomly paired binders were also discovered with the natively paired method. Additionally, 33% of the scFv binders discovered only in the randomly paired library were initially present in the natively paired pre-sort library. Thus, a significant proportion of “randomly paired” scFv were actually natively paired. We synthesized and produced 46 of the candidates as full-length antibodies and subjected them to a panel of binding assays to characterize their therapeutic potential. 87% of the antibodies were verified as binding IL-21R by at least one assay. We found that antibodies with native light chains were more likely to bind IL-21R than antibodies with non-native light chains, suggesting a higher false positive rate for antibodies from the randomly paired library. Additionally, the randomly paired method failed to identify nearly half of the true natively paired binders, suggesting a higher false negative rate. We conclude that natively paired libraries have critical advantages in sensitivity and specificity for antibody discovery programs. PMID:29376776

Formation of pyroglutamic acid from N-terminal glutamic acid in immunoglobulin gamma antibodies.

PubMed

Chelius, Dirk; Jing, Kay; Lueras, Alexis; Rehder, Douglas S; Dillon, Thomas M; Vizel, Alona; Rajan, Rahul S; Li, Tiansheng; Treuheit, Michael J; Bondarenko, Pavel V

2006-04-01

The status of the N-terminus of proteins is important for amino acid sequencing by Edman degradation, protein identification by shotgun and top-down techniques, and to uncover biological functions, which may be associated with modifications. In this study, we investigated the pyroglutamic acid formation from N-terminal glutamic acid residues in recombinant monoclonal antibodies. Almost half the antibodies reported in the literature contain a glutamic acid residue at the N-terminus of the light or the heavy chain. Our reversed-phase high-performance liquid chromatography-mass spectrometry method could separate the pyroglutamic acid-containing light chains from the native light chains of reduced and alkylated recombinant monoclonal antibodies. Tryptic peptide mapping and tandem mass spectrometry of the reduced and alkylated proteins was used for the identification of the pyroglutamic acid. We identified the formation of pyroglutamic acid from N-terminal glutamic acid in the heavy chains and light chains of several antibodies, indicating that this nonenzymatic reaction does occur very commonly and can be detected after a few weeks of incubation at 37 and 45 degrees C. The rate of this reaction was measured in several aqueous buffers with different pH values, showing minimal formation of pyroglutamic acid at pH 6.2 and increased formation of pyroglutamic acid at pH 4 and pH 8. The half-life of the N-terminal glutamic acid was approximately 9 months in a pH 4.1 buffer at 45 degrees C. To our knowledge, we showed for the first time that glutamic acid residues located at the N-terminus of proteins undergo pyroglutamic acid formation in vitro.

Mechanical properties of lipid bilayers from molecular dynamics simulation

PubMed Central

Venable, Richard M.; Brown, Frank L.H.; Pastor, Richard W.

2015-01-01

Lipid areas (Aℓ), bilayer area compressibilities (KA), bilayer bending constants (KC), and monolayer spontaneous curvatures (c0) from simulations using the CHARMM36 force field are reported for 12 representative homogenous lipid bilayers. Aℓ (or their surrogate, the average deuterium order parameter in the “plateau region” of the chain) agree very well with experiment, as do the KA. Simulated KC are in near quantitative agreement with vesicle flicker experiments, but are somewhat larger than KC from x-ray, pipette aspiration, and neutron spin echo for saturated lipids. Spontaneous curvatures of bilayer leaflets from the simulations are approximately 30% smaller than experimental values of monolayers in the inverse hexagonal phase. PMID:26238099

Chlamydocin analogs bearing carbonyl group as possible ligand toward zinc atom in histone deacetylases.

PubMed

Bhuiyan, Mohammed P I; Kato, Tamaki; Okauchi, Tatsuo; Nishino, Norikazu; Maeda, Satoko; Nishino, Tomonori G; Yoshida, Minoru

2006-05-15

A series of chlamydocin analogs with various carbonyl functionalities were designed and synthesized as histone deacetylase (HDAC) inhibitors. Chlamydocin is a cyclic tetrapeptide containing an epoxyketone surrogate in the side chain which makes it irreversible inhibitor of HDACs, whereas apicidins are a class of cyclic tetrapeptides that contain an ethylketone moiety as zinc ligand. We replaced the epoxyketone moiety of chlamydocin with several ketones and aldehyde to synthesize potent reversible and selective HDAC inhibitors. The inhibitory activity of the cyclic tetrapeptides against histone deacetylase enzymes were evaluated and the result showed most of them are potent inhibitors. Some of them have remarkable selectivity among the HDACs.

Critical care physicians' approaches to negotiating with surrogate decision makers: a qualitative study.

PubMed

Brush, David R; Brown, Crystal E; Alexander, G Caleb

2012-04-01

To describe how critical care physicians manage conflicts with surrogates about withdrawing or withholding patients' life support. Qualitative analysis of key informant interviews with critical care physicians during 2010. We transcribed interviews verbatim and used grounded theory to code and revise a taxonomy of themes and to identify illustrative quotes. Three academic medical centers, one academic-affiliated medical center, and four private practice groups or private hospitals in a large Midwestern city Fourteen critical care physicians. None. Physicians reported tailoring their approach to address specific reasons for disagreement with surrogates. Five common approaches were identified: 1) building trust; 2) educating and informing; 3) providing surrogates more time; 4) adjusting surrogate and physician roles; and 5) highlighting specific values. When mistrust was an issue, physicians endeavored to build a more trusting relationship with the surrogate before readdressing decision making. Physicians also reported correcting misunderstandings by providing targeted education, and some reported highlighting specific patient, surrogate, or physician values that they hoped would guide surrogates to agree with them. When surrogates struggled with decisionmaking roles, physicians attempted to reinforce the concept of substituted judgment. Physicians noted that some surrogates needed time to "come to terms" with the patent's illness before agreeing with physicians. Many physicians had witnessed colleagues negotiate in ways they found objectionable such as providing misleading information, injecting their own values into the negotiation or behaving unprofessionally toward surrogates. Although some physicians viewed their efforts to encourage surrogates' agreement as persuasive, others strongly denied persuading surrogates and described their actions as "guiding" or "negotiating." Physicians reported using a tailored approach to resolve decisional conflicts about life support and attempted to change surrogates' decisions in accordance with what the physician thought was in the patients' best interests. Although physicians acknowledged their efforts to change surrogates' decisions, many physicians did not perceive these efforts as persuasive.

Audio-visual feedback improves the BCI performance in the navigational control of a humanoid robot

PubMed Central

Tidoni, Emmanuele; Gergondet, Pierre; Kheddar, Abderrahmane; Aglioti, Salvatore M.

2014-01-01

Advancement in brain computer interfaces (BCI) technology allows people to actively interact in the world through surrogates. Controlling real humanoid robots using BCI as intuitively as we control our body represents a challenge for current research in robotics and neuroscience. In order to successfully interact with the environment the brain integrates multiple sensory cues to form a coherent representation of the world. Cognitive neuroscience studies demonstrate that multisensory integration may imply a gain with respect to a single modality and ultimately improve the overall sensorimotor performance. For example, reactivity to simultaneous visual and auditory stimuli may be higher than to the sum of the same stimuli delivered in isolation or in temporal sequence. Yet, knowledge about whether audio-visual integration may improve the control of a surrogate is meager. To explore this issue, we provided human footstep sounds as audio feedback to BCI users while controlling a humanoid robot. Participants were asked to steer their robot surrogate and perform a pick-and-place task through BCI-SSVEPs. We found that audio-visual synchrony between footsteps sound and actual humanoid's walk reduces the time required for steering the robot. Thus, auditory feedback congruent with the humanoid actions may improve motor decisions of the BCI's user and help in the feeling of control over it. Our results shed light on the possibility to increase robot's control through the combination of multisensory feedback to a BCI user. PMID:24987350

Sepia ink as a surrogate for colloid transport tests in porous media

NASA Astrophysics Data System (ADS)

Soto-Gómez, Diego; Pérez-Rodríguez, Paula; López-Periago, J. Eugenio; Paradelo, Marcos

2016-08-01

We examined the suitability of the ink of Sepia officinalis as a surrogate for transport studies of microorganisms and microparticles in porous media. Sepia ink is an organic pigment consisted on a suspension of eumelanin, and that has several advantages for its use as a promising material for introducing the frugal-innovation in the fields of public health and environmental research: very low cost, non-toxic, spherical shape, moderate polydispersivity, size near large viruses, non-anomalous electrokinetic behavior, low retention in the soil, and high stability. Electrokinetic determinations and transport experiments in quartz sand columns and soil columns were done with purified suspensions of sepia ink. Influence of ionic strength on the electrophoretic mobility of ink particles showed the typical behavior of polystyrene latex spheres. Breakthrough curve (BTC) and retention profile (RP) in quartz sand columns showed a depth dependent and blocking adsorption model with an increase in adsorption rates with the ionic strength. Partially saturated transport through undisturbed soil showed less retention than in quartz sand, and matrix exclusion was also observed. Quantification of ink in leachate fractions by light absorbance is direct, but quantification in the soil profile with moderate to high organic matter content was rather cumbersome. We concluded that sepia ink is a suitable cheap surrogate for exploring transport of pathogenic viruses, bacteria and particulate contaminants in groundwater, and could be used for developing frugal-innovation related with the assessment of soil and aquifer filtration function, and monitoring of water filtration systems in low-income regions.

Comparative higher-order structure analysis of antibody biosimilars using combined bottom-up and top-down hydrogen-deuterium exchange mass spectrometry.

PubMed

Pan, Jingxi; Zhang, Suping; Borchers, Christoph H

2016-12-01

Hydrogen/deuterium exchange (HDX) coupled with mass spectrometry (MS) is a powerful technique for higher-order structural characterization of antibodies. Although the peptide-based bottom-up HDX approach and the protein-based top-down HDX approach have complementary advantages, the work done so far on biosimilars has involved only one or the other approach. Herein we have characterized the structures of two bevacizumab (BEV) biosimilars and compared them to the reference BEV using both methods. A sequence coverage of 87% was obtained for the heavy chain and 74% for the light chain in the bottom-up approach. The deuterium incorporation behavior of the peptic peptides from the three BEVs were compared side by side and showed no differences at various HDX time points. Top-down experiments were carried out using subzero temperature LC-MS, and the deuterium incorporation of the intact light chain and heavy chain were obtained. Top-down ETD was also performed to obtain amino acid-level HDX information that covered 100% of the light chain, but only 50% coverage is possible for the heavy chain. Consistent with the intact subunit level data, no differences were observed in the amino acid level HDX data. All these results indicate that there are no differences between the three BEV samples with respect to their high-order structures. The peptide level information from the bottom-up approach, and the residue level and intact subunit level information from the top-down approach were complementary and covered the entire antibody. Copyright © 2016 Elsevier B.V. All rights reserved.

A rank test for bivariate time-to-event outcomes when one event is a surrogate

PubMed Central

Shaw, Pamela A.; Fay, Michael P.

2016-01-01

In many clinical settings, improving patient survival is of interest but a practical surrogate, such as time to disease progression, is instead used as a clinical trial’s primary endpoint. A time-to-first endpoint (e.g. death or disease progression) is commonly analyzed but may not be adequate to summarize patient outcomes if a subsequent event contains important additional information. We consider a surrogate outcome very generally, as one correlated with the true endpoint of interest. Settings of interest include those where the surrogate indicates a beneficial outcome so that the usual time-to-first endpoint of death or surrogate event is nonsensical. We present a new two-sample test for bivariate, interval-censored time-to-event data, where one endpoint is a surrogate for the second, less frequently observed endpoint of true interest. This test examines whether patient groups have equal clinical severity. If the true endpoint rarely occurs, the proposed test acts like a weighted logrank test on the surrogate; if it occurs for most individuals, then our test acts like a weighted logrank test on the true endpoint. If the surrogate is a useful statistical surrogate, our test can have better power than tests based on the surrogate that naively handle the true endpoint. In settings where the surrogate is not valid (treatment affects the surrogate but not the true endpoint), our test incorporates the information regarding the lack of treatment effect from the observed true endpoints and hence is expected to have a dampened treatment effect compared to tests based on the surrogate alone. PMID:27059817

Surrogate outcomes in health technology assessment: an international comparison.

PubMed

Velasco Garrido, Marcial; Mangiapane, Sandra

2009-07-01

Our aim was to review the recommendations given by health technology assessment (HTA) institutions in their methodological guidelines concerning the use of surrogate outcomes in their assessments. In a second step, we aimed at quantifying the role surrogate parameters take in assessment reports. We analyzed methodological papers and guidelines from HTA agencies with International Network of Agencies for Health Technology Assessment membership as well as from institutions related to pharmaceutical regulation (i.e., reimbursement, pricing). We analyzed the use of surrogate outcomes in a sample of HTA reports randomly drawn from the HTA database. We checked methods, results (including evidence tables), and conclusions sections and extracted the outcomes reported. We report descriptive statistics on the presence of surrogate outcomes in the reports. We identified thirty-four methodological guidelines, twenty of them addressing the issue of outcome parameter choice and the problematic of surrogate outcomes. Overall HTA agencies call on caution regarding the reliance on surrogate outcomes. None of the agencies has provided a list or catalog of acceptable and validated surrogate outcomes. We extracted the outcome parameter of 140 HTA reports. Only around half of the reports determined the outcomes for the assessment prospectively. Surrogate outcomes had been used in 62 percent of the reports. However, only 3.6 percent were based upon surrogate outcomes exclusively. All of them assessed diagnostic or screening technologies and the surrogate outcomes were predominantly test characteristics. HTA institutions seem to agree on a cautious approach to the use of surrogate outcomes in technology assessment. Thorough assessment of health technologies should not rely exclusively on surrogate outcomes.

Advanced topics in evidence-based urologic oncology: surrogate endpoints.

PubMed

Lavallée, Luke T; Montori, Victor M; Canfield, Stephen E; Breau, Rodney H

2011-01-01

Clinical trials often report surrogate endpoint data. A surrogate endpoint is a biological marker or clinical sign that can be substituted for a patient-important outcome. Using surrogate endpoints correctly may facilitate and expedite clinical trials and may improve medical decisions. However, rigorous criteria must be met for an endpoint to be considered a valid surrogate. The purpose of this article is to review the topic of surrogate endpoints in the context of a urologic encounter. Copyright © 2011 Elsevier Inc. All rights reserved.

Serum Free Light Chain Assay and κ/λ Ratio: Performance in Patients With Monoclonal Gammopathy-High False Negative Rate for κ/λ Ratio

PubMed Central

Singh, Gurmukh

2017-01-01

Background Serum free light chain assay (SFLCA) and κ/λ ratio, and protein electrophoretic methods are used in the diagnosis and monitoring of monoclonal gammopathies. Methods Results for serum free light chains, serum and urine protein electrophoreses and immunofixation electrophoreses in 468 patients with a diagnosis of monoclonal gammopathy were compared. The results of the two methods were graded as concordant, non-concordant or discordant with the established diagnoses to assess the relative performance of the methods. Results of κ/λ ratio in samples with monoclonal protein detectable by electrophoretic methods were also analyzed. Results Protein electrophoreses results were concordant with the established diagnoses significantly more often than κ/λ ratio. The false negative rate for κ/λ ratio was higher than that for electrophoretic methods. κ/λ ratio was falsely negative in about 27% of the 1,860 samples with detectable monoclonal immunoglobulin. The false negative rate was higher in lesions with lambda chains (32%) than those with kappa chains (24%). The false negative rate for κ/λ ratio was over 55% in samples with monoclonal gammopathy of undetermined significance. Even at first encounter, the false negative rates for κ/λ ratios for monoclonal gammopathy of undetermined significance, smoldering myeloma and multiple myeloma were 66.98%, 23.08%, and 30.15%, respectively, with false negative rate for lambda chain lesions being higher. Conclusions Electrophoretic studies of serum and urine are superior to SFLCA and κ/λ ratio. Abnormal κ/λ ratio, per se, is not diagnostic of monoclonal gammopathy. A normal κ/λ ratio does not exclude monoclonal gammopathy. False negative rates for lesions with lambda chain are higher than those for lesions with kappa chains. Electrophoretic studies of urine are underutilized. Clinical usefulness and medical necessity of SFLCA and κ/λ ratio is of questionable value in routine clinical testing. PMID:27924175

Serum Free Light Chain Assay and κ/λ Ratio: Performance in Patients With Monoclonal Gammopathy-High False Negative Rate for κ/λ Ratio.

PubMed

Singh, Gurmukh

2017-01-01

Serum free light chain assay (SFLCA) and κ/λ ratio, and protein electrophoretic methods are used in the diagnosis and monitoring of monoclonal gammopathies. Results for serum free light chains, serum and urine protein electrophoreses and immunofixation electrophoreses in 468 patients with a diagnosis of monoclonal gammopathy were compared. The results of the two methods were graded as concordant, non-concordant or discordant with the established diagnoses to assess the relative performance of the methods. Results of κ/λ ratio in samples with monoclonal protein detectable by electrophoretic methods were also analyzed. Protein electrophoreses results were concordant with the established diagnoses significantly more often than κ/λ ratio. The false negative rate for κ/λ ratio was higher than that for electrophoretic methods. κ/λ ratio was falsely negative in about 27% of the 1,860 samples with detectable monoclonal immunoglobulin. The false negative rate was higher in lesions with lambda chains (32%) than those with kappa chains (24%). The false negative rate for κ/λ ratio was over 55% in samples with monoclonal gammopathy of undetermined significance. Even at first encounter, the false negative rates for κ/λ ratios for monoclonal gammopathy of undetermined significance, smoldering myeloma and multiple myeloma were 66.98%, 23.08%, and 30.15%, respectively, with false negative rate for lambda chain lesions being higher. Electrophoretic studies of serum and urine are superior to SFLCA and κ/λ ratio. Abnormal κ/λ ratio, per se , is not diagnostic of monoclonal gammopathy. A normal κ/λ ratio does not exclude monoclonal gammopathy. False negative rates for lesions with lambda chain are higher than those for lesions with kappa chains. Electrophoretic studies of urine are underutilized. Clinical usefulness and medical necessity of SFLCA and κ/λ ratio is of questionable value in routine clinical testing.

A Single-Chain Photoswitchable CRISPR-Cas9 Architecture for Light-Inducible Gene Editing and Transcription.

PubMed

Zhou, Xin X; Zou, Xinzhi; Chung, Hokyung K; Gao, Yuchen; Liu, Yanxia; Qi, Lei S; Lin, Michael Z

2018-02-16

Optical control of CRISPR-Cas9-derived proteins would be useful for restricting gene editing or transcriptional regulation to desired times and places. Optical control of Cas9 functions has been achieved with photouncageable unnatural amino acids or by using light-induced protein interactions to reconstitute Cas9-mediated functions from two polypeptides. However, these methods have only been applied to one Cas9 species and have not been used for optical control of different perturbations at two genes. Here, we use photodissociable dimeric fluorescent protein domains to engineer single-chain photoswitchable Cas9 (ps-Cas9) proteins in which the DNA-binding cleft is occluded at baseline and opened upon illumination. This design successfully controlled different species and functional variants of Cas9, mediated transcriptional activation more robustly than previous optogenetic methods, and enabled light-induced transcription of one gene and editing of another in the same cells. Thus, a single-chain photoswitchable architecture provides a general method to control a variety of Cas9-mediated functions.

Planarian myosin essential light chain is involved in the formation of brain lateral branches during regeneration.

PubMed

Yu, Shuying; Chen, Xuhui; Yuan, Zuoqing; Zhou, Luming; Pang, Qiuxiang; Mao, Bingyu; Zhao, Bosheng

2015-08-01

The myosin essential light chain (ELC) is a structure component of the actomyosin cross-bridge, however, the functions in the central nervous system (CNS) development and regeneration remain poorly understood. Planarian Dugesia japonica has revealed fundamental mechanisms and unique aspects of neuroscience and neuroregeneration. In this study, the cDNA DjElc, encoding a planarian essential light chain of myosin, was identified from the planarian Dugesia japonica cDNA library. It encodes a deduced protein with highly conserved functionally domains EF-Hand and Ca(2+) binding sites that shares significant similarity with other members of ELC. Whole mount in situ hybridization studies show that DjElc expressed in CNS during embryonic development and regeneration of adult planarians. Loss of function of DjElc by RNA interference during planarian regeneration inhibits brain lateral branches regeneration completely. In conclusion, these results demonstrated that DjElc is required for maintenance of neurons and neurite outgrowth, particularly for involving the brain later branch regeneration.

Gladiolus plants transformed with single-chain variable fragment antibodies to Cucumber mosaic virus

USDA-ARS?s Scientific Manuscript database

Transgenic plants of Gladiolus ‘Peter Pears’ or ‘Jenny Lee’ were developed that contain single-chain variable fragments (scFv) to Cucumber mosaic virus (CMV) subgroup I or II. The CMV subgroup I heavy and light chain scFv fragments were placed under control of either the duplicated CaMV 35S or suga...

Nonspinning numerical relativity waveform surrogates: assessing the model

NASA Astrophysics Data System (ADS)

Field, Scott; Blackman, Jonathan; Galley, Chad; Scheel, Mark; Szilagyi, Bela; Tiglio, Manuel

2015-04-01

Recently, multi-modal gravitational waveform surrogate models have been built directly from data numerically generated by the Spectral Einstein Code (SpEC). I will describe ways in which the surrogate model error can be quantified. This task, in turn, requires (i) characterizing differences between waveforms computed by SpEC with those predicted by the surrogate model and (ii) estimating errors associated with the SpEC waveforms from which the surrogate is built. Both pieces can have numerous sources of numerical and systematic errors. We make an attempt to study the most dominant error sources and, ultimately, the surrogate model's fidelity. These investigations yield information about the surrogate model's uncertainty as a function of time (or frequency) and parameter, and could be useful in parameter estimation studies which seek to incorporate model error. Finally, I will conclude by comparing the numerical relativity surrogate model to other inspiral-merger-ringdown models. A companion talk will cover the building of multi-modal surrogate models.

The generation and selection of single-domain, v region libraries from nurse sharks.

PubMed

Flajnik, Martin F; Dooley, Helen

2009-01-01

The cartilaginous fish (sharks, skates, and rays) are the oldest phylogenetic group in which a human-type adaptive immune system and immunoglobulins (Igs) have been found. In addition to their conventional (heavy-light chain heterodimeric) isotypes, IgM and IgW, sharks produce the novel isotype, IgNAR, a heavy chain homodimer that does not associate with light chains. Instead, its variable (V) regions act as independent, soluble units in order to bind antigen. In this chapter, we detail our immunization protocol in order to raise a humoral IgNAR response in the nurse shark (Ginglymostoma cirratum) and the subsequent cloning of the single-domain V regions from this isotype in order to select antigen-specific binders by phage display.

Development of an ultralow-light-level luminescence image analysis system for dynamic measurements of transcriptional activity in living and migrating cells.

PubMed

Maire, E; Lelièvre, E; Brau, D; Lyons, A; Woodward, M; Fafeur, V; Vandenbunder, B

2000-04-10

We have developed an approach to study in single living epithelial cells both cell migration and transcriptional activation, which was evidenced by the detection of luminescence emission from cells transfected with luciferase reporter vectors. The image acquisition chain consists of an epifluorescence inverted microscope, connected to an ultralow-light-level photon-counting camera and an image-acquisition card associated to specialized image analysis software running on a PC computer. Using a simple method based on a thin calibrated light source, the image acquisition chain has been optimized following comparisons of the performance of microscopy objectives and photon-counting cameras designed to observe luminescence. This setup allows us to measure by image analysis the luminescent light emitted by individual cells stably expressing a luciferase reporter vector. The sensitivity of the camera was adjusted to a high value, which required the use of a segmentation algorithm to eliminate the background noise. Following mathematical morphology treatments, kinetic changes of luminescent sources were analyzed and then correlated with the distance and speed of migration. Our results highlight the usefulness of our image acquisition chain and mathematical morphology software to quantify the kinetics of luminescence changes in migrating cells.

Function of fusion regulatory proteins (FRPs) in immune cells and virus-infected cells.

PubMed

Tsurudome, M; Ito, Y

2000-01-01

Two molecules that regulate cell fusion have been identified and designated fusion regulatory protein-1 (FRP-1) and FRP-2. FRP-1 is a complex composed of a glycosylated heavy chain and a nonglycosylated light chain that are disulfide linked. FRP-1 heavy chain is identical to 4F2/CD98 heavy chain, whereas FRP-2 is identical to integrin alpha3 subunit. The FRP-1 heavy chain is a multifunctional molecule: that is, fusion regulator, amino acid transporter, integrin regulator, comitogenic factor, Na+-Ca2+ exchanger, oncogenic protein, and so on. Several aspects of the structure and function of the FRP-1 system are reviewed: fusion regulatory molecular mechanisms, cross-talk between the FRP-1 and integrin, the FRP-1 system as amino acid transporter, and FRP-1-mediated T-cell activation. The FRP-1 system is involved in virus-mediated cell fusion and multinucleated giant cell formation of blood monocytes. Monoclonal antibodies against human FRP-1 heavy chain induce polykaryocytes that have properties as osteoclasts. Multiple steps participate in molecular mechanisms regulating cell fusion. The FRP-1 heavy chain supports amino acid transport activity and the FRP-1 light chains have recently been cloned as amino acid transporters that require association with the heavy chain to exhibit their activity. Novel pathways for monocyte-dependent regulation of T-cell activation have recently been found that are mediated by the FRP-1 system. In conclusion, the FRP-1 molecules are essential factors for basic cellular functions.

Surrogate endpoints and emerging surrogate endpoints for risk reduction of cardiovascular disease.

PubMed

Rasnake, Crystal M; Trumbo, Paula R; Heinonen, Therese M

2008-02-01

This article reviews surrogate endpoints and emerging biomarkers that were discussed at the annual "Cardiovascular Biomarkers and Surrogate Endpoints" symposium cosponsored by the US Food and Drug Administration (FDA) and the Montreal Heart Institute. The FDA's Center for Food Safety and Applied Nutrition (CFSAN) uses surrogate endpoints in its scientific review of a substance/disease relationship for a health claim. CFSAN currently recognizes three validated surrogate endpoints: blood pressure, blood total cholesterol, and blood low-density lipoprotein (LDL) concentration in its review of a health claim for cardiovascular disease (CVD). Numerous potential surrogate endpoints of CVD are being evaluated as the pathophysiology of heart disease is becoming better understood. However, these emerging biomarkers need to be validated as surrogate endpoints before they are used by CFSAN in the evaluation of a CVD health claim.

Surrogate matrix and surrogate analyte approaches for definitive quantitation of endogenous biomolecules.

PubMed

Jones, Barry R; Schultz, Gary A; Eckstein, James A; Ackermann, Bradley L

2012-10-01

Quantitation of biomarkers by LC-MS/MS is complicated by the presence of endogenous analytes. This challenge is most commonly overcome by calibration using an authentic standard spiked into a surrogate matrix devoid of the target analyte. A second approach involves use of a stable-isotope-labeled standard as a surrogate analyte to allow calibration in the actual biological matrix. For both methods, parallelism between calibration standards and the target analyte in biological matrix must be demonstrated in order to ensure accurate quantitation. In this communication, the surrogate matrix and surrogate analyte approaches are compared for the analysis of five amino acids in human plasma: alanine, valine, methionine, leucine and isoleucine. In addition, methodology based on standard addition is introduced, which enables a robust examination of parallelism in both surrogate analyte and surrogate matrix methods prior to formal validation. Results from additional assays are presented to introduce the standard-addition methodology and to highlight the strengths and weaknesses of each approach. For the analysis of amino acids in human plasma, comparable precision and accuracy were obtained by the surrogate matrix and surrogate analyte methods. Both assays were well within tolerances prescribed by regulatory guidance for validation of xenobiotic assays. When stable-isotope-labeled standards are readily available, the surrogate analyte approach allows for facile method development. By comparison, the surrogate matrix method requires greater up-front method development; however, this deficit is offset by the long-term advantage of simplified sample analysis.

Surrogate end points in clinical research: hazardous to your health.

PubMed

Grimes, David A; Schulz, Kenneth F

2005-05-01

Surrogate end points in clinical research pose real danger. A surrogate end point is an outcome measure, commonly a laboratory test, that substitutes for a clinical event of true importance. Resistance to activated protein C, for example, has been used as a surrogate for venous thrombosis in women using oral contraceptives. Other examples of inappropriate surrogate end points in contraception include the postcoital test instead of pregnancy to evaluate new spermicides, breakage and slippage instead of pregnancy to evaluate condoms, and bone mineral density instead of fracture to assess the safety of depo-medroxyprogesterone acetate. None of these markers captures the effect of the treatment on the true outcome. A valid surrogate end point must both correlate with and accurately predict the outcome of interest. Although many surrogate markers correlate with an outcome, few have been shown to capture the effect of a treatment (for example, oral contraceptives) on the outcome (venous thrombosis). As a result, thousands of useless and misleading reports on surrogate end points litter the medical literature. New drugs have been shown to benefit a surrogate marker, but, paradoxically, triple the risk of death. Thousands of patients have died needlessly because of reliance on invalid surrogate markers. Researchers should avoid surrogate end points unless they have been validated; that requires at least one well done trial using both the surrogate and true outcome. The clinical maxim that "a difference to be a difference must make a difference" applies to research as well. Clinical research should focus on outcomes that matter.

Treatment With Bortezomib-based Therapy, Followed by Autologous Stem Cell Transplantation, Improves Outcomes in Light Chain Amyloidosis: A Retrospective Study.

PubMed

Jain, Tania; Kosiorek, Heidi E; Kung, Shu T; Shah, Vishal S; Dueck, Amylou C; Gonzalez-Calle, Veronica; Luft, Susan; Reeder, Craig B; Adams, Roberta; Noel, Pierre; Larsen, Jeremy T; Mikhael, Joseph; Bergsagel, Leif; Stewart, A Keith; Fonseca, Rafael

2018-05-04

The hematologic response is critical in patients with light chain amyloidosis because a good response is known to improve organ response and overall survival. We present a retrospective analysis to compare the hematologic and organ response in patients who received bortezomib-based therapy before autologous stem cell transplantation (ASCT) versus those who received non-bortezomib-based therapy before ASCT and those who underwent ASCT at diagnosis. Of a total of 63 patients who underwent ASCT for light chain amyloidosis, 34 received bortezomib-based therapy before ASCT (Bor-ASCT) and 29 did not receive bortezomib therapy (non-Bor-ASCT). A greater number of patients had involvement of ≥ 3 organs and cardiac involvement in the Bor-ASCT group, suggesting a greater risk at baseline in the Bor-ASCT group. At 3, 6, and 12 months after ASCT, the hematologic response was better in the Bor-ASCT group, with a statistically significance difference at 6 months (partial response or better in 82% vs. 20%; P = .002) and 12 months (partial response or better in 76% vs. 33%; P = .02). Organ responses (66% vs. 21%; P < .001) and median overall survival (not reached vs. 53 months; P = .001) were also greater in the Bor-ASCT group. Our study has shown that bortezomib-based therapy before ASCT improves the hematologic response, organ response and overall survival, potentially by decreasing the light chain load before ASCT. Copyright © 2018 Elsevier Inc. All rights reserved.

Covalent Binding Antibodies Suppress Advanced Glycation: On the Innate Tier of Adaptive Immunity

PubMed Central

Shcheglova, T.; Makker, S. P.

2009-01-01

Non-enzymatic protein glycation is a source of metabolic stress that contributes to cytotoxicity and tissue damage. Hyperglycemia has been linked to elevation of advanced glycation endproducts, which mediate much of the vascular pathology leading to diabetic complications. Enhanced glycation of immunoglobulins and their accelerated vascular clearance is proposed as a natural mechanism to intercept alternative advanced glycation endproducts, thereby mitigating microvascular disease. We reported that antibodies against the glycoprotein KLH have elevated reactivity for glycopeptides from diabetic serum. These reactions are mediated by covalent binding between antibody light chains and carbonyl groups of glycated peptides. Diabetic animals that were immunized to induce reactive antibodies had attenuated diabetic nephropathy, which correlated with reduced levels of circulating and kidney-bound glycation products. Molecular analysis of antibody glycation revealed the preferential modification of light chains bearing germline-encoded lambda V regions. We previously noted that antibody fragments carrying V regions in the germline configuration are selected from a human Fv library by covalent binding to a reactive organophosphorus ester. These Fv fragments were specifically modified at light chain V region residues, which map to the combining site at the interface between light and heavy chains. These findings suggest that covalent binding is an innate property of antibodies, which may be encoded in the genome for specific physiological purposes. This hypothesis is discussed in context with current knowledge of the natural antibodies that recognize altered self molecules and the catalytic autoantibodies found in autoimmune disease. PMID:22649604

Method for altering antibody light chain interactions

DOEpatents

Stevens, Fred J.; Stevens, Priscilla Wilkins; Raffen, Rosemarie; Schiffer, Marianne

2002-01-01

A method for recombinant antibody subunit dimerization including modifying at least one codon of a nucleic acid sequence to replace an amino acid occurring naturally in the antibody with a charged amino acid at a position in the interface segment of the light polypeptide variable region, the charged amino acid having a first polarity; and modifying at least one codon of the nucleic acid sequence to replace an amino acid occurring naturally in the antibody with a charged amino acid at a position in an interface segment of the heavy polypeptide variable region corresponding to a position in the light polypeptide variable region, the charged amino acid having a second polarity opposite the first polarity. Nucleic acid sequences which code for novel light chain proteins, the latter of which are used in conjunction with the inventive method, are also provided.

The representation of healthcare end users' perspectives by surrogates in healthcare decisions: a literature review.

PubMed

Shah, Syed Ghulam Sarwar; Farrow, Alexandra; Robinson, Ian

2009-12-01

The representation of end users' perspectives in healthcare decisions requires involvement of their surrogates when the end users, i.e. certain patients, elderly people, children and people with disabilities, are unable to present their views. To review critical issues, and the advantages and disadvantages of involving surrogates in representing end users' perspectives in healthcare decisions. A systematic review of literature published in peer-reviewed journals from 1990 to 2005. Findings show that surrogates are used widely in health care and that they are necessary to represent end users' perspectives in healthcare decisions when the latter are unable to do so themselves. Critical issues in using surrogates include key ethical, social, cultural, legal and medico-technological factors; ascertaining the best interest of end users; potential conflict of interest; possible biased decisions and the burden on surrogates. The key advantage of surrogate involvement in healthcare decisions is their ability to represent end users' needs, values and wishes. The main disadvantages include potential discrepancies between the decisions and conclusions of surrogates and end users; the failure of surrogates to predict end users' preferences accurately and the lack of certainty that useful information will be obtained through the surrogacy process. This systematic review has revealed that the involvement of surrogates is an additional vital way to represent end users' perspectives in healthcare decisions where for a range of reasons their opinions are unable to be effectively ascertained. However, because of the heterogeneity of surrogates and end users, the selection of appropriate surrogates and deploying surrogate decisions require particularly careful consideration of their value in individual cases; thus, subsequent decision-making must be reviewed on a case-to-case basis to seek to ensure that the best interests, needs and wishes of the end user are fully and accurately represented.

The Trial of Ascertaining Individual Preferences for Loved Ones' Role in End-of-Life Decisions (TAILORED) Study: A Randomized Controlled Trial to Improve Surrogate Decision Making.

PubMed

Sulmasy, Daniel P; Hughes, Mark T; Yenokyan, Gayane; Kub, Joan; Terry, Peter B; Astrow, Alan B; Johnson, Julie A; Ho, Grace; Nolan, Marie T

2017-10-01

Patients with terminal illnesses often require surrogate decision makers. Prior research has demonstrated high surrogate stress, and that despite standards promoting substituted judgment, most patients do not want their surrogates to make pure substituted judgments for them. It is not known how best to help loved ones fulfill the surrogate role. To test the effectiveness of an intervention to help surrogate decision makers. One hundred sixty-six patients (41% with amyotrophic lateral sclerosis and 59% with gastrointestinal cancers) and their surrogates at two university medical centers were randomized to an intensive nurse-directed discussion of the end-of-life decision control preferences of the patient (TAILORED) or a discussion of nutrition (CONTROL); 163 completed baseline interviews and underwent the intervention. Twelve patients died during follow-up and 137 dyads completed the study. Post-intervention, using all available data, TAILORED patients and surrogates became more likely to endorse mutual surrogate decision making, that is, a balance of their own wishes and what the surrogate thinks best (adjusted odds compared with baseline for patients = 1.78, P = 0.04; adjusted odds for surrogates = 2.05, P = 0.03). CONTROL patients became 40% less likely to endorse mutual surrogate decision making (P = 0.08), and CONTROL surrogates did not change significantly from baseline (adjusted odds = 1.44, P = 0.28). Stress levels decreased for TAILORED surrogates (impact of events scale = 23.1 ± 14.6 baseline, 20.8 ± 15.3 f/u, P = 0.046), but not for CONTROL (P = 0.85), and post-intervention stress was lower for TAILORED than CONTROL (P = 0.04). Surrogates' confidence was uniformly high at baseline and did not change. Caregiver burden (Zarit) increased from 12.5 ± 6.5 to 14.7 ± 8.1 for TAILORED (P < 0.01), while not changing for CONTROL, yet satisfaction with involvement in decision making was higher at follow-up for TAILORED than for CONTROL (71% vs. 52%, P = 0.03). TAILORED patients and surrogates who completed the study adopted a more mutual decision-making style, balancing their own wishes with what the surrogate thinks would be best for them. Surrogates reported less stress and more satisfaction. Confidence was high at baseline and did not change. There was a modest increase in caregiver burden. These findings suggest that interventions like TAILORED might positively impact surrogate decision making. Copyright © 2017 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

High-throughput sequencing of natively paired antibody chains provides evidence for original antigenic sin shaping the antibody response to influenza vaccination.

PubMed

Tan, Yann-Chong; Blum, Lisa K; Kongpachith, Sarah; Ju, Chia-Hsin; Cai, Xiaoyong; Lindstrom, Tamsin M; Sokolove, Jeremy; Robinson, William H

2014-03-01

We developed a DNA barcoding method to enable high-throughput sequencing of the cognate heavy- and light-chain pairs of the antibodies expressed by individual B cells. We used this approach to elucidate the plasmablast antibody response to influenza vaccination. We show that >75% of the rationally selected plasmablast antibodies bind and neutralize influenza, and that antibodies from clonal families, defined by sharing both heavy-chain VJ and light-chain VJ sequence usage, do so most effectively. Vaccine-induced heavy-chain VJ regions contained on average >20 nucleotide mutations as compared to their predicted germline gene sequences, and some vaccine-induced antibodies exhibited higher binding affinities for hemagglutinins derived from prior years' seasonal influenza as compared to their affinities for the immunization strains. Our results show that influenza vaccination induces the recall of memory B cells that express antibodies that previously underwent affinity maturation against prior years' seasonal influenza, suggesting that 'original antigenic sin' shapes the antibody response to influenza vaccination. Published by Elsevier Inc.

Enhanced photocatalytic activity of degrading short chain chlorinated paraffins over reduced graphene oxide/CoFe2O4/Ag nanocomposite.

PubMed

Chen, Xin; Zhao, Qidong; Li, Xinyong; Wang, Dong

2016-10-01

Short chain chlorinated paraffins have recently attracted great attention because of their environmental persistence and biological toxicity as an important organic pollutant. In this work, reduced graphene oxide/CoFe2O4/Ag (RGO/CoFe2O4/Ag) nanocomposite was prepared and employed for photocatalytic degradation of short chain chlorinated paraffins. The process of photocatalytic degradation of short chain chlorinated paraffins over RGO/CoFe2O4/Ag under visible light (λ>400nm) was investigated by in situ Fourier transform infrared spectroscopy and the related mechanisms were proposed. An apparent degradation ratio of 91.9% over RGO/CoFe2O4/Ag could be obtained under visible light illumination of 12h, while only about 21.7% was obtained with commercial P25 TiO2 under the same experimental conditions, which demonstrates that the RGO/CoFe2O4/Ag nanocomposite is a potential candidate for effective photocatalytic removal of short chain chlorinated paraffins. Copyright © 2016 Elsevier Inc. All rights reserved.

A perfect correlate does not a surrogate make

PubMed Central

Baker, Stuart G; Kramer, Barnett S

2003-01-01

Background There is common belief among some medical researchers that if a potential surrogate endpoint is highly correlated with a true endpoint, then a positive (or negative) difference in potential surrogate endpoints between randomization groups would imply a positive (or negative) difference in unobserved true endpoints between randomization groups. We investigate this belief when the potential surrogate and unobserved true endpoints are perfectly correlated within each randomization group. Methods We use a graphical approach. The vertical axis is the unobserved true endpoint and the horizontal axis is the potential surrogate endpoint. Perfect correlation within each randomization group implies that, for each randomization group, potential surrogate and true endpoints are related by a straight line. In this scenario the investigator does not know the slopes or intercepts. We consider a plausible example where the slope of the line is higher for the experimental group than for the control group. Results In our example with unknown lines, a decrease in mean potential surrogate endpoints from control to experimental groups corresponds to an increase in mean true endpoint from control to experimental groups. Thus the potential surrogate endpoints give the wrong inference. Similar results hold for binary potential surrogate and true outcomes (although the notion of correlation does not apply). The potential surrogate endpointwould give the correct inference if either (i) the unknown lines for the two group coincided, which means that the distribution of true endpoint conditional on potential surrogate endpoint does not depend on treatment group, which is called the Prentice Criterion or (ii) if one could accurately predict the lines based on data from prior studies. Conclusion Perfect correlation between potential surrogate and unobserved true outcomes within randomized groups does not guarantee correct inference based on a potential surrogate endpoint. Even in early phase trials, investigators should not base conclusions on potential surrogate endpoints in which the only validation is high correlation with the true endpoint within a group. PMID:12962545

Sediment transport and evaluation of sediment surrogate ratings in the Kootenai River near Bonners Ferry, Idaho, Water Years 2011–14

USGS Publications Warehouse

Wood, Molly S.; Fosness, Ryan L.; Etheridge, Alexandra B.

2015-12-14

Acoustic surrogate ratings were developed between backscatter data collected using acoustic Doppler velocity meters (ADVMs) and results of suspended-sediment samples. Ratings were successfully fit to various sediment size classes (total, fines, and sands) using ADVMs of different frequencies (1.5 and 3 megahertz). Surrogate ratings also were developed using variations of streamflow and seasonal explanatory variables. The streamflow surrogate ratings produced average annual sediment load estimates that were 8–32 percent higher, depending on site and sediment type, than estimates produced using the acoustic surrogate ratings. The streamflow surrogate ratings tended to overestimate suspended-sediment concentrations and loads during periods of elevated releases from Libby Dam as well as on the falling limb of the streamflow hydrograph. Estimates from the acoustic surrogate ratings more closely matched suspended-sediment sample results than did estimates from the streamflow surrogate ratings during these periods as well as for rating validation samples collected in water year 2014. Acoustic surrogate technologies are an effective means to obtain continuous, accurate estimates of suspended-sediment concentrations and loads for general monitoring and sediment-transport modeling. In the Kootenai River, continued operation of the acoustic surrogate sites and use of the acoustic surrogate ratings to calculate continuous suspended-sediment concentrations and loads will allow for tracking changes in sediment transport over time.

Toward a Psychology of Surrogate Decision Making.

PubMed

Tunney, Richard J; Ziegler, Fenja V

2015-11-01

In everyday life, many of the decisions that we make are made on behalf of other people. A growing body of research suggests that we often, but not always, make different decisions on behalf of other people than the other person would choose. This is problematic in the practical case of legally designated surrogate decision makers, who may not meet the substituted judgment standard. Here, we review evidence from studies of surrogate decision making and examine the extent to which surrogate decision making accurately predicts the recipient's wishes, or if it is an incomplete or distorted application of the surrogate's own decision-making processes. We find no existing domain-general model of surrogate decision making. We propose a framework by which surrogate decision making can be assessed and a novel domain-general theory as a unifying explanatory concept for surrogate decisions. © The Author(s) 2015.

Effects of Fuel Composition on Combustion Stability and NO X Emissions for Traditional and Alternative Jet Fuels

NASA Astrophysics Data System (ADS)

Vijlee, Shazib Z.

Synthetic jet fuels are studied to help understand their viability as alternatives to traditionally derived jet fuel. Two combustion parameters -- flame stability and NOX emissions -- are used to compare these fuels through experiments and models. At its core, this is a fuels study comparing how chemical makeup and behavior relate. Six 'real', complex fuels are studied in this work -- four are synthetic from alternative sources and two are traditional from petroleum sources. Two of the synthetic fuels are derived from natural gas and coal via the Fischer Tropsch catalytic process. The other two are derived from Camelina oil and tallow via hydroprocessing. The traditional military jet fuel, JP8, is used as a baseline as it is derived from petroleum. The sixth fuel is derived from petroleum and is used to study the effects of aromatic content on the synthetic fuels. The synthetic fuels lack aromatic compounds, which are an important class of hydrocarbons necessary for fuel handling systems to function properly. Several single-component fuels are studied (through models and/or experiments) to facilitate interpretation and understanding. The flame stability study first compares all the 'real', complex fuels for blowout. A toroidal stirred reactor is used to try and isolate temperature and chemical effects. The modeling study of blowout in the toroidal reactor is the key to understanding any fuel-based differences in blowout behavior. A detailed, reacting CFD model of methane is used to understand how the reactor stabilizes the flame and how that changes as the reactor approaches blowout. A 22 species reduced form of GRI 3.0 is used to model methane chemistry. The knowledge of the radical species role is utilized to investigate the differences between a highly aliphatic fuel (surrogated by iso-octane) and a highly aromatic fuel (surrogated by toluene). A perfectly stirred reactor model is used to study the chemical kinetic pathways for these fuels near blowout. The differences in flame stabilization can be attributed to the rate at which these fuels are attacked and destroyed by radical species. The slow disintegration of the aromatic rings reduces the radical pool available for chain-initiating and chain-branching, which ultimately leads to an earlier blowout. The NOX study compares JP8, the aromatic additive, the synthetic fuels with and without an aromatic additive, and an aromatic surrogate (1,3,5-trimethylbenzene). A jet stirred reactor is used to try and isolate temperature and chemical effects. The reactor has a volume of 15.8 mL and a residence time of approximately 2.5 ms. The fuel flow rate (hence equivalence ratio) is adjusted to achieve nominally consistent temperatures of 1800, 1850, and 1900K. Small oscillations in fuel flow rate cause the data to appear in bands, which facilitated Arrhenius-type NOX-temperature correlations for direct comparison between fuels. The fuel comparisons are somewhat inconsistent, especially when the aromatic fuel is blended into the synthetic fuels. In general, the aromatic surrogate (1,3,5-trimethylbenzene) produces the most NOX, followed by JP8. The synthetic fuels (without aromatic additive) are always in the same ranking order for NOX production (HP Camelina > FT Coal > FT Natural Gas > HP Tallow). The aromatic additive ranks differently based on the temperature, which appears to indicate that some of the differences in NOX formation are due to the Zeldovich NOX formation pathway. The aromatic additive increases NOX for the HP Tallow and decreases NOX for the FT Coal. The aromatic additive causes increased NOX at low temperatures but decreases NOX at high temperatures for the HP Camelina and FT Natural Gas. A single perfectly stirred reactor model is used with several chemical kinetic mechanisms to study the effects of fuel (and fuel class) on NO X formation. The 27 unique NOX formation reactions from GRI 3.0 are added to published mechanisms for jet fuel surrogates. The investigation first looked at iso-octane and toluene and found that toluene produces more NOX because of a larger pool of O radical. The O radical concentration was lower for iso-octane because of an increased concentration of methyl (CH 3) radical that consumes O radical readily. Several surrogate fuels (iso-octane, toluene, propylcyclohexane, n-octane, and 1,3,5-trimethylbenzene) are modeled to look for differences in NOX production. The trend (increased CH3 → decreased O → decreased NOX) is consistently true for all surrogate fuels with multiple kinetic mechanisms. It appears that the manner in which the fuel disintegrates and creates methyl radical is an extremely important aspect of how much NOX a fuel will produce. (Abstract shortened by UMI.).

Solar Photothermal Disinfection using Broadband-Light Absorbing Gold Nanoparticles and Carbon Black.

PubMed

Loeb, Stephanie; Li, Chuanhao; Kim, Jae-Hong

2018-01-02

A simple heat treatment, perhaps the most globally recognized point-of-use water sterilization method, is seemingly effective against all major pathogens of concern, but bulk water boiling is not energy efficient or sustainable. Herein, we present the first application of solar-to-thermal converting nanomaterials for the direct inactivation of bacteria and viruses in drinking water through the application of Au nanorods, carbon black, and Au nanorod-carbon black composite materials as light absorbers. With broad absorption bands spanning the visible and near-infrared wavelengths, at sufficient concentrations, these nanoparticles induce multiple scattering events, increasing photon absorption probability and concentrating the light within a small spatial domain, leading to localized, intense heating that inactivates microorganisms in close proximity. Moving toward practical device design, we have developed a facile silane immobilization approach to fabricate films with densely packed layers of photothermal nanomaterials. Our results suggest that upon irraditaion with simulated solar light, these films can thermally inactivate bacteria and viruses, as demonstrated through the inactivation of surrogate organisms Escherichia coli K-12, and bacteriophages MS2 and PR772.

Inference of reaction rate parameters based on summary statistics from experiments

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

Khalil, Mohammad; Chowdhary, Kamaljit Singh; Safta, Cosmin

Here, we present the results of an application of Bayesian inference and maximum entropy methods for the estimation of the joint probability density for the Arrhenius rate para meters of the rate coefficient of the H 2/O 2-mechanism chain branching reaction H + O 2 → OH + O. Available published data is in the form of summary statistics in terms of nominal values and error bars of the rate coefficient of this reaction at a number of temperature values obtained from shock-tube experiments. Our approach relies on generating data, in this case OH concentration profiles, consistent with the givenmore » summary statistics, using Approximate Bayesian Computation methods and a Markov Chain Monte Carlo procedure. The approach permits the forward propagation of parametric uncertainty through the computational model in a manner that is consistent with the published statistics. A consensus joint posterior on the parameters is obtained by pooling the posterior parameter densities given each consistent data set. To expedite this process, we construct efficient surrogates for the OH concentration using a combination of Pad'e and polynomial approximants. These surrogate models adequately represent forward model observables and their dependence on input parameters and are computationally efficient to allow their use in the Bayesian inference procedure. We also utilize Gauss-Hermite quadrature with Gaussian proposal probability density functions for moment computation resulting in orders of magnitude speedup in data likelihood evaluation. Despite the strong non-linearity in the model, the consistent data sets all res ult in nearly Gaussian conditional parameter probability density functions. The technique also accounts for nuisance parameters in the form of Arrhenius parameters of other rate coefficients with prescribed uncertainty. The resulting pooled parameter probability density function is propagated through stoichiometric hydrogen-air auto-ignition computations to illustrate the need to account for correlation among the Arrhenius rate parameters of one reaction and across rate parameters of different reactions.« less

Inference of reaction rate parameters based on summary statistics from experiments

DOE PAGES

Khalil, Mohammad; Chowdhary, Kamaljit Singh; Safta, Cosmin; ...

2016-10-15

Here, we present the results of an application of Bayesian inference and maximum entropy methods for the estimation of the joint probability density for the Arrhenius rate para meters of the rate coefficient of the H 2/O 2-mechanism chain branching reaction H + O 2 → OH + O. Available published data is in the form of summary statistics in terms of nominal values and error bars of the rate coefficient of this reaction at a number of temperature values obtained from shock-tube experiments. Our approach relies on generating data, in this case OH concentration profiles, consistent with the givenmore » summary statistics, using Approximate Bayesian Computation methods and a Markov Chain Monte Carlo procedure. The approach permits the forward propagation of parametric uncertainty through the computational model in a manner that is consistent with the published statistics. A consensus joint posterior on the parameters is obtained by pooling the posterior parameter densities given each consistent data set. To expedite this process, we construct efficient surrogates for the OH concentration using a combination of Pad'e and polynomial approximants. These surrogate models adequately represent forward model observables and their dependence on input parameters and are computationally efficient to allow their use in the Bayesian inference procedure. We also utilize Gauss-Hermite quadrature with Gaussian proposal probability density functions for moment computation resulting in orders of magnitude speedup in data likelihood evaluation. Despite the strong non-linearity in the model, the consistent data sets all res ult in nearly Gaussian conditional parameter probability density functions. The technique also accounts for nuisance parameters in the form of Arrhenius parameters of other rate coefficients with prescribed uncertainty. The resulting pooled parameter probability density function is propagated through stoichiometric hydrogen-air auto-ignition computations to illustrate the need to account for correlation among the Arrhenius rate parameters of one reaction and across rate parameters of different reactions.« less

Bayesian prediction of future ice sheet volume using local approximation Markov chain Monte Carlo methods

NASA Astrophysics Data System (ADS)

Davis, A. D.; Heimbach, P.; Marzouk, Y.

2017-12-01

We develop a Bayesian inverse modeling framework for predicting future ice sheet volume with associated formal uncertainty estimates. Marine ice sheets are drained by fast-flowing ice streams, which we simulate using a flowline model. Flowline models depend on geometric parameters (e.g., basal topography), parameterized physical processes (e.g., calving laws and basal sliding), and climate parameters (e.g., surface mass balance), most of which are unknown or uncertain. Given observations of ice surface velocity and thickness, we define a Bayesian posterior distribution over static parameters, such as basal topography. We also define a parameterized distribution over variable parameters, such as future surface mass balance, which we assume are not informed by the data. Hyperparameters are used to represent climate change scenarios, and sampling their distributions mimics internal variation. For example, a warming climate corresponds to increasing mean surface mass balance but an individual sample may have periods of increasing or decreasing surface mass balance. We characterize the predictive distribution of ice volume by evaluating the flowline model given samples from the posterior distribution and the distribution over variable parameters. Finally, we determine the effect of climate change on future ice sheet volume by investigating how changing the hyperparameters affects the predictive distribution. We use state-of-the-art Bayesian computation to address computational feasibility. Characterizing the posterior distribution (using Markov chain Monte Carlo), sampling the full range of variable parameters and evaluating the predictive model is prohibitively expensive. Furthermore, the required resolution of the inferred basal topography may be very high, which is often challenging for sampling methods. Instead, we leverage regularity in the predictive distribution to build a computationally cheaper surrogate over the low dimensional quantity of interest (future ice sheet volume). Continual surrogate refinement guarantees asymptotic sampling from the predictive distribution. Directly characterizing the predictive distribution in this way allows us to assess the ice sheet's sensitivity to climate variability and change.

A cross-cultural study on surrogate mother's empathy and maternal-foetal attachment.

PubMed

Lorenceau, Ellen Schenkel; Mazzucca, Luis; Tisseron, Serge; Pizitz, Todd D

2015-06-01

Traditional and gestational surrogate mothers assist infertile couples by carrying their children. In 2005, a meta-analysis on surrogacy was conducted but no study had examined empathy and maternal-foetal attachment of surrogate mothers. Assessments of surrogate mothers show no sign of psychopathology, but one study showed differences on several MMPI-2 scales compared to a normative sample: surrogate mothers identified with stereotypically masculine traits such as assertiveness and competition. They had a higher self-esteem and lower levels of anxiety and depression. To determine if there is a difference in empathy and maternal-foetal attachment of surrogate mothers compared to a comparison group of mothers. Three groups of European traditional and gestational surrogate mothers (n=10), Anglo-Saxon traditional and gestational surrogate mothers (n=34) and a European normative sample of mothers (n=32) completed four published psychometric instruments: the Interpersonal Reactivity Index (empathy index), the Hospital Anxiety and Depressions Scale and the MC20, a social desirability scale. Pregnant surrogate mothers filled the Maternal Antenatal Attachment Scale (n=11). Statistical non-parametric analyses of variance were conducted. Depending on cultural background, surrogate mothers present differences in terms of empathy, anxiety and depression, social desirability and quality of attachment to the foetus compared to a normative sample. Environment plays a role for traditional and gestational surrogacy. Surrogate mothers of both groups are less anxious and depressed than normative samples. Maternal-foetal attachment is strong with a slightly lower quality of attachment. Surrogate mother's empathy indexes are similar to normative samples, sometimes higher. Copyright © 2014 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

The associative relation underlying autoshaping in the pigeon1

PubMed Central

Woodruff, Guy; Williams, D. R.

1976-01-01

Fifteen pigeons were exposed to either response-independent or response-dependent schedules of water reinforcement, whereby water was injected directly into the unrestrained pigeons' mandibles. Key-contact responses were released by a lighted key correlated with water, but not by a lighted key uncorrelated with water. A negative response-reinforcer contingency suppressed autoshaped key-contact responses, resulting in responding directed away from the lighted key. In all pigeons, water injected directly into the mandibles elicited a consummatory fixed-action pattern of “mumbling” and swallowing. The lighted key correlated with water released a broader set of both appetitive and consummatory responses: approach to the lighted key, “bowing”, “rooting”, “mumbling”, and swallowing. Key-contact responses were “rooting” and “mumbling” motions of the beak on the surface of the key. Views of autoshaping based on stimulus substitution or stimulus surrogation do not fully explain the origin of autoshaped responses not previously elicited by the reinforcer. The present findings are consonant with views of conditioning that emphasize the large degree of biological pre-organization in conditioned response patterns, and the importance of associative factors in the control of such patterns. PMID:16811924

Comparing and combining biomarkers as principle surrogates for time-to-event clinical endpoints.

PubMed

Gabriel, Erin E; Sachs, Michael C; Gilbert, Peter B

2015-02-10

Principal surrogate endpoints are useful as targets for phase I and II trials. In many recent trials, multiple post-randomization biomarkers are measured. However, few statistical methods exist for comparison of or combination of biomarkers as principal surrogates, and none of these methods to our knowledge utilize time-to-event clinical endpoint information. We propose a Weibull model extension of the semi-parametric estimated maximum likelihood method that allows for the inclusion of multiple biomarkers in the same risk model as multivariate candidate principal surrogates. We propose several methods for comparing candidate principal surrogates and evaluating multivariate principal surrogates. These include the time-dependent and surrogate-dependent true and false positive fraction, the time-dependent and the integrated standardized total gain, and the cumulative distribution function of the risk difference. We illustrate the operating characteristics of our proposed methods in simulations and outline how these statistics can be used to evaluate and compare candidate principal surrogates. We use these methods to investigate candidate surrogates in the Diabetes Control and Complications Trial. Copyright © 2014 John Wiley & Sons, Ltd.

The psychological well-being and prenatal bonding of gestational surrogates

PubMed Central

Lamba, N; Jadva, V; Kadam, K; Golombok, S

2018-01-01

Abstract STUDY QUESTION How does the psychological well-being and prenatal bonding of Indian surrogates differ from a comparison group of mothers? SUMMARY ANSWER Surrogates had higher levels of depression during pregnancy and post-birth, displayed lower emotional connection with the unborn baby, and greater care towards the healthy growth of the foetus, than the comparison group of mothers. WHAT IS ALREADY KNOWN Studies in the West have found that surrogates do not suffer long-term psychological harm. One study has shown that surrogates bond less with the foetus than expectant mothers. STUDY, DESIGN, SIZE, DURATION This study uses a prospective, longitudinal and cross-sectional design. Surrogates and a matched group of expectant mothers were seen twice, during 4–9 months of pregnancy and 4–6 months after the birth. PARTICIPANTS/MATERIALS, SETTING, METHODS Semi-structured interviews and standardized questionnaires were administered to 50 surrogates and 69 expectant mothers during pregnancy and 45 surrogates and 49 expectant mothers post-birth. All gestational surrogates were hosting pregnancies for international intended parents. MAIN RESULTS AND THE ROLE OF CHANCE Surrogates had higher levels of depression compared to the comparison group of mothers, during pregnancy and post-birth (P < 0.02). Low social support during pregnancy, hiding surrogacy and criticism from others were found to be predictive of higher depression in surrogates post-birth (P < 0.05). Regarding prenatal bonding, surrogates interacted less with and thought less about the foetus but adopted better eating habits and were more likely to avoid unhealthy practices during pregnancy, than expectant mothers (P < 0.05). No associations were found between greater prenatal bonding and greater psychological distress during pregnancy or after relinquishment. LIMITATIONS, REASONS FOR CAUTION All surrogates were recruited from one clinic in Mumbai, and thus the representativeness of this sample is not known. Also, the possibility of socially desirable responding from surrogates cannot be ruled out. WIDER IMPLICATIONS OF THE FINDINGS As this is the first study of the psychological well-being of surrogates in low-income countries, the findings have important policy implications. Providing support and counselling to surrogates, especially during pregnancy, may alleviate some of the psychological problems faced by surrogates. STUDY FUNDING/COMPETING INTEREST(S) This study was supported by the Wellcome Trust [097857/Z/11/Z] and Nehru Trust, Cambridge. K.K. is the Medical Director of Corion Fertility Clinic. All other authors have no conflict of interest to declare. PMID:29566176

Successful application of the dual-vector system II in creating a reliable phage-displayed combinatorial Fab library.

PubMed

Song, Suk-yoon; Hur, Byung-ung; Lee, Kyung-woo; Choi, Hyo-jung; Kim, Sung-soo; Kang, Goo; Cha, Sang-hoon

2009-03-31

The dual-vector system-II (DVS-II), which allows efficient display of Fab antibodies on phage, has been reported previously, but its practical applicability in a phage-displayed antibody library has not been verified. To resolve this issue, we created two small combinatorial human Fab antibody libraries using the DVS-II, and isolation of target-specific antibodies was attempted. Biopanning of one antibody library, termed DVFAB-1L library, which has a 1.3 x 10(7) combinatorial antibody complexity, against fluorescein-BSA resulted in successful isolation of human Fab clones specific for the antigen despite the presence of only a single light chain in the library. By using the unique feature of the DVS-II, an antibody library of a larger size, named DVFAB-131L, which has a 1.5 x 10(9) combinatorial antibody complexity, was also generated in a rapid manner by combining 1.3 x 10(7) heavy chains and 131 light chains and more diverse anti-fluorescein-BSA Fab antibody clones were successfully obtained. Our results demonstrate that the DVS-II can be applied readily in creating phage-displayed antibody libraries with much less effort, and target-specific antibody clones can be isolated reliably via light chain promiscuity of antibody molecule.

Centrocins: isolation and characterization of novel dimeric antimicrobial peptides from the green sea urchin, Strongylocentrotus droebachiensis.

PubMed

Li, Chun; Haug, Tor; Moe, Morten K; Styrvold, Olaf B; Stensvåg, Klara

2010-09-01

As immune effector molecules, antimicrobial peptides (AMPs) play an important role in the invertebrate immune system. Here, we present two novel AMPs, named centrocins 1 (4.5kDa) and 2 (4.4kDa), purified from coelomocyte extracts of the green sea urchin, Strongylocentrotus droebachiensis. The native peptides are cationic and show potent activities against Gram-positive and Gram-negative bacteria. The centrocins have an intramolecular heterodimeric structure, containing a heavy chain (30 amino acids) and a light chain (12 amino acids). The cDNA encoding the peptides and genomic sequences were cloned and sequenced. One putative isoform (centrocin 1b) was identified and one intron was found in the genes coding for the centrocins. The full length protein sequence of centrocin 1 consists of 119 amino acids, whereas centrocin 2 consists of 118 amino acids which both include a preprosequence of 51 or 50 amino acids for centrocins 1 and 2, respectively, and an interchain of 24 amino acids between the heavy and light chain. The difference of molecular mass between the native centrocins and the deduced sequences from cDNA indicates that the native centrocins contain a post-translational brominated tryptophan. In addition, two amino acids at the C-terminal, Gly-Arg, were removed from the light chains during the post-translational processing. The separate peptide chains of centrocin 1 were synthesized and the heavy chain alone was shown to be sufficient for antimicrobial activity. The genome of the closely related species, the purple sea urchin (S. purpuratus), was shown to contain two putative proteins with high similarity to the centrocins. Copyright 2010 Elsevier Ltd. All rights reserved.

Integrability in heavy quark effective theory

NASA Astrophysics Data System (ADS)

Braun, Vladimir M.; Ji, Yao; Manashov, Alexander N.

2018-06-01

It was found that renormalization group equations in the heavy-quark effective theory (HQET) for the operators involving one effective heavy quark and light degrees of freedom are completely integrable in some cases and are related to spin chain models with the Hamiltonian commuting with the nondiagonal entry C( u) of the monodromy matrix. In this work we provide a more complete mathematical treatment of such spin chains in the QISM framework. We also discuss the relation of integrable models that appear in the HQET context with the large-spin limit of integrable models in QCD with light quarks. We find that the conserved charges and the "ground state" wave functions in HQET models can be obtained from the light-quark counterparts in a certain scaling limit.

Surrogate Agreement in Tzotzil.

ERIC Educational Resources Information Center

Aissen, Judith L.

This study investigates whether other relationships in sentence structure besides the "brother-in-law" relation sanction surrogate agreement in Zinacanteco Tzotzil (Mayan). Surrogate agreement refers to cases in which an element that lies outside the class of regular agreement controllers in a language (the surrogate) controls…

Surrogate endpoints in randomized cardiovascular clinical trials.

PubMed

Domanski, Michael; Pocock, Stuart; Bernaud, Corine; Borer, Jeffrey; Geller, Nancy; Revkin, James; Zannad, Faiez

2011-08-01

Surrogate endpoints predict the occurrence and timing of a clinical endpoint of interest (CEI). Substitution of a surrogate endpoint for a CEI can dramatically reduce the time and cost necessary to complete a Phase III clinical trial. However, assurance that use of a surrogate endpoint will result in a correct conclusion regarding treatment effect on a CEI requires prior rigorous validation of the surrogate. Surrogate endpoints can also be of substantial use in Phase I and II studies to assess whether the intended therapeutic pathway is operative, thus providing assurance regarding the reasonableness of proceeding to a Phase III trial. This paper discusses the uses and validation of surrogate endpoints. © 2010 The Authors Fundamental and Clinical Pharmacology © 2010 Société Française de Pharmacologie et de Thérapeutique.

Local recurrence as immunoglobulin G4 (IgG4)-related disease 10 years after radiotherapy to ocular adnexal extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue.

PubMed

Matsuo, Toshihiko; Ichimura, Kouichi; Yoshino, Tadashi

2011-01-01

In 2000, a 48-year-old woman developed a left orbital mass with lacrimal gland involvement and then, in 2003, a right orbital mass with lacrimal gland involvement, both of which were diagnosed as extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). She underwent 30 Gy external beam radiation to bilateral orbital lesions. The lymphoma cells in both lesions did not share the same clonality, as shown by amplification by polymerase chain reaction of the immunoglobulin heavy chain gene. Immunoglobulin light chain analysis by immunohistochemistry and messenger RNA in situ hybridization showed λ chain monotype in the left orbital lesion but κ chain monotype in the right orbital lesion. She developed recurrent left orbital mass with high uptake on fluorodeoxyglucose positron emission tomography fused with computed tomography in 2010, and excisional biopsy disclosed the formation of follicles and infiltration with immunoglobulin G4 (IgG4)-positive plasma cells mainly in interfollicular areas. The immunoglobulin light chain analysis showed the λ chain and κ chain bitype. With the immunohistopathological diagnosis of IgG4-related disease, the serum IgG4 level was found to show elevation at 376 mg/dL, and the patient chose observation. This is the first reported case of development of IgG4-related disease after bilataral orbital MALT lymphoma with external beam radiotherapy.

A review of selection-based tests of abiotic surrogates for species representation.

PubMed

Beier, Paul; Sutcliffe, Patricia; Hjort, Jan; Faith, Daniel P; Pressey, Robert L; Albuquerque, Fabio

2015-06-01

Because conservation planners typically lack data on where species occur, environmental surrogates--including geophysical settings and climate types--have been used to prioritize sites within a planning area. We reviewed 622 evaluations of the effectiveness of abiotic surrogates in representing species in 19 study areas. Sites selected using abiotic surrogates represented more species than an equal number of randomly selected sites in 43% of tests (55% for plants) and on average improved on random selection of sites by about 8% (21% for plants). Environmental diversity (ED) (42% median improvement on random selection) and biotically informed clusters showed promising results and merit additional testing. We suggest 4 ways to improve performance of abiotic surrogates. First, analysts should consider a broad spectrum of candidate variables to define surrogates, including rarely used variables related to geographic separation, distance from coast, hydrology, and within-site abiotic diversity. Second, abiotic surrogates should be defined at fine thematic resolution. Third, sites (the landscape units prioritized within a planning area) should be small enough to ensure that surrogates reflect species' environments and to produce prioritizations that match the spatial resolution of conservation decisions. Fourth, if species inventories are available for some planning units, planners should define surrogates based on the abiotic variables that most influence species turnover in the planning area. Although species inventories increase the cost of using abiotic surrogates, a modest number of inventories could provide the data needed to select variables and evaluate surrogates. Additional tests of nonclimate abiotic surrogates are needed to evaluate the utility of conserving nature's stage as a strategy for conservation planning in the face of climate change. © 2015 Society for Conservation Biology.

Surrogacy families 10 years on: relationship with the surrogate, decisions over disclosure and children's understanding of their surrogacy origins

PubMed Central

Jadva, V.; Blake, L.; Casey, P.; Golombok, S.

2012-01-01

BACKGROUND This study aimed to prospectively examine families created using surrogacy over a 10-year period in the UK with respect to intending parents' and children's relationship with the surrogate mother, parents' decisions over disclosure and children's understanding of the nature of their conception. METHODS Semi-structured interviews were administered by trained researchers to intending mothers, intending fathers and children on four occasions over a 10-year period. Forty-two families (19 with a genetic surrogate mother) participated when the child was 1-year old and by age 10 years, 33 families remained in the study. Data were collected on the frequency of contact with the surrogate mother, relationship with the surrogate, disclosure of surrogacy to the child and the child's understanding of their surrogacy birth. RESULTS Frequency of contact between surrogacy families and their surrogate mother decreased over time, particularly for families whose surrogate was a previously unknown genetic carrier (P < 0.001) (i.e. where they had met through a third party and the surrogate mother's egg was used to conceive the child). Most families reported harmonious relationships with their surrogate mother. At age 10 years, 19 (90%) children who had been informed of the nature of their conception had a good understanding of this and 13 of the 14 children who were in contact with their surrogate reported that they liked her. CONCLUSIONS Surrogacy families maintained good relationships with the surrogate mother over time. Children felt positive about their surrogate mother and their surrogacy birth. The sample size of this study was small and further, larger investigations are needed before firm conclusions can be drawn. PMID:22814484

Surrogate endpoints in oncology: when are they acceptable for regulatory and clinical decisions, and are they currently overused?

PubMed

Kemp, Robert; Prasad, Vinay

2017-07-21

Surrogate outcomes are not intrinsically beneficial to patients, but are designed to be easier and faster to measure than clinically meaningful outcomes. The use of surrogates as an endpoint in clinical trials and basis for regulatory approval is common, and frequently exceeds the guidance given by regulatory bodies. In this article, we demonstrate that the use of surrogates in oncology is widespread and increasing. At the same time, the strength of association between the surrogates used and clinically meaningful outcomes is often unknown or weak. Attempts to validate surrogates are rarely undertaken. When this is done, validation relies on only a fraction of available data, and often concludes that the surrogate is poor. Post-marketing studies, designed to ensure drugs have meaningful benefits, are often not performed. Alternatively, if a drug fails to improve quality of life or overall survival, market authorization is rarely revoked. We suggest this reliance on surrogates, and the imprecision surrounding their acceptable use, means that numerous drugs are now approved based on small yet statistically significant increases in surrogates of questionable reliability. In turn, this means the benefits of many approved drugs are uncertain. This is an unacceptable situation for patients and professionals, as prior experience has shown that such uncertainty can be associated with significant harm. The use of surrogate outcomes should be limited to situations where a surrogate has demonstrated robust ability to predict meaningful benefits, or where cases are dire, rare or with few treatment options. In both cases, surrogates must be used only when continuing studies examining hard endpoints have been fully recruited.

Surrogacy families 10 years on: relationship with the surrogate, decisions over disclosure and children's understanding of their surrogacy origins.

PubMed

Jadva, V; Blake, L; Casey, P; Golombok, S

2012-10-01

This study aimed to prospectively examine families created using surrogacy over a 10-year period in the UK with respect to intending parents' and children's relationship with the surrogate mother, parents' decisions over disclosure and children's understanding of the nature of their conception. Semi-structured interviews were administered by trained researchers to intending mothers, intending fathers and children on four occasions over a 10-year period. Forty-two families (19 with a genetic surrogate mother) participated when the child was 1-year old and by age 10 years, 33 families remained in the study. Data were collected on the frequency of contact with the surrogate mother, relationship with the surrogate, disclosure of surrogacy to the child and the child's understanding of their surrogacy birth. Frequency of contact between surrogacy families and their surrogate mother decreased over time, particularly for families whose surrogate was a previously unknown genetic carrier (P < 0.001) (i.e. where they had met through a third party and the surrogate mother's egg was used to conceive the child). Most families reported harmonious relationships with their surrogate mother. At age 10 years, 19 (90%) children who had been informed of the nature of their conception had a good understanding of this and 13 of the 14 children who were in contact with their surrogate reported that they liked her. Surrogacy families maintained good relationships with the surrogate mother over time. Children felt positive about their surrogate mother and their surrogacy birth. The sample size of this study was small and further, larger investigations are needed before firm conclusions can be drawn.

Effect of low electric fields on alpha scintillation light yield in liquid argon

NASA Astrophysics Data System (ADS)

Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; Alton, A. K.; Asner, D. M.; Back, H. O.; Baldin, B.; Biery, K.; Bocci, V.; Bonfini, G.; Bonivento, W.; Bossa, M.; Bottino, B.; Brigatti, A.; Brodsky, J.; Budano, F.; Bussino, S.; Cadeddu, M.; Cadoni, M.; Calaprice, F.; Canci, N.; Candela, A.; Caravati, M.; Cariello, M.; Carlini, M.; Catalanotti, S.; Cavalcante, P.; Chepurnov, A.; Cicalò, C.; Cocco, A. G.; Covone, G.; D'Angelo, D.; D'Incecco, M.; Davini, S.; De Cecco, S.; De Deo, M.; De Vincenzi, M.; Derbin, A.; Devoto, A.; Di Eusanio, F.; Di Pietro, G.; Dionisi, C.; Edkins, E.; Empl, A.; Fan, A.; Fiorillo, G.; Fomenko, K.; Forster, G.; Franco, D.; Gabriele, F.; Galbiati, C.; Giagu, S.; Giganti, C.; Giovanetti, G. K.; Goretti, A. M.; Granato, F.; Gromov, M.; Guan, M.; Guardincerri, Y.; Hackett, B. R.; Herner, K.; Hughes, D.; Humble, P.; Hungerford, E. V.; Ianni, A.; James, I.; Johnson, T. N.; Jollet, C.; Keeter, K.; Kendziora, C. L.; Koh, G.; Korablev, D.; Korga, G.; Kubankin, A.; Li, X.; Lissia, M.; Loer, B.; Lombardi, P.; Longo, G.; Ma, Y.; Machulin, I. N.; Mandarano, A.; Mari, S. M.; Maricic, J.; Marini, L.; Martoff, C. J.; Meregaglia, A.; Meyers, P. D.; Milincic, R.; Miller, J. D.; Montanari, D.; Monte, A.; Mount, B. J.; Muratova, V. N.; Musico, P.; Napolitano, J.; Navrer Agasson, A.; Odrowski, S.; Oleinik, A.; Orsini, M.; Ortica, F.; Pagani, L.; Pallavicini, M.; Pantic, E.; Parmeggiano, S.; Pelczar, K.; Pelliccia, N.; Pocar, A.; Pordes, S.; Pugachev, D. A.; Qian, H.; Randle, K.; Ranucci, G.; Razeti, M.; Razeto, A.; Reinhold, B.; Renshaw, A. L.; Rescigno, M.; Riffard, Q.; Romani, A.; Rossi, B.; Rossi, N.; Rountree, D.; Sablone, D.; Saggese, P.; Sands, W.; Savarese, C.; Schlitzer, B.; Segreto, E.; Semenov, D. A.; Shields, E.; Singh, P. N.; Skorokhvatov, M. D.; Smirnov, O.; Sotnikov, A.; Stanford, C.; Suvorov, Y.; Tartaglia, R.; Tatarowicz, J.; Testera, G.; Tonazzo, A.; Trinchese, P.; Unzhakov, E. V.; Verducci, M.; Vishneva, A.; Vogelaar, B.; Wada, M.; Walker, S.; Wang, H.; Wang, Y.; Watson, A. W.; Westerdale, S.; Wilhelmi, J.; Wojcik, M. M.; Xiang, X.; Xiao, X.; Xu, J.; Yang, C.; Zhong, W.; Zhu, C.; Zuzel, G.

2017-01-01

Measurements were made of scintillation light yield of alpha particles from the 222Rn decay chain within the DarkSide-50 liquid argon time projection chamber. The light yield was found to increase as the applied electric field increased, with alphas in a 200 V/cm electric field exhibiting a ~2% increase in light yield compared to alphas in no field.

A simple method to determine IgG light chain to heavy chain polypeptide ratios expressed by CHO cells.

PubMed

Gerster, Anja; Wodarczyk, Claas; Reichenbächer, Britta; Köhler, Janet; Schulze, Andreas; Krause, Felix; Müller, Dethardt

2016-12-01

To establish a high-throughput method for determination of antibodies intra- and extracellular light chain (LC) to heavy chain (HC) polypeptide ratio as screening parameter during cell line development. Chinese Hamster Ovary (CHO) TurboCell pools containing different designed vectors supposed to result in different LC:HC polypeptide ratios were generated by targeted integration. Cell culture supernatants and cell lysates of a fed batch experiment were purified by combined Protein A and anti-kappa affinity batch purification in 96-well format. Capture of all antibodies and their fragments allowed the determination of the intra- and extracellular LC:HC peptide ratios by reduced SDS capillary electrophoresis. Results demonstrate that the method is suitable to show the significant impact of the vector design on the intra- and extracellular LC:HC polypeptide ratios. Determination of LC:HC polypeptide ratios can give important information in vector design optimization leading to CHO cell lines with optimized antibody assembly and preferred product quality.

Control of in vivo disposition and immunogenicity of polymeric micelles by adjusting poly(sarcosine) chain lengths on surface

NASA Astrophysics Data System (ADS)

Kurihara, Kensuke; Ueda, Motoki; Hara, Isao; Ozeki, Eiichi; Togashi, Kaori; Kimura, Shunsaku

2017-07-01

Four kinds of A3B-type amphiphilic polydepsipeptides, (poly(sarcosine))3- b-poly( l-lactic acid) (the degree of polymerization of poly(sarcosine) are 10, 33, 55, and 85; S10 3 , S33 3 , S55 3 , and S85 3 ) were synthesized to prepare core-shell type polymeric micelles. Their in vivo dispositions and stimulations to trigger immune system to produce IgM upon multiple administrations to mice were examined. With increasing poly(sarcosine) chain lengths, the hydrophilic shell became thicker and the surface density at the most outer surface decreased on the basis of dynamic and static light scattering measurements. These two physical elements of polymeric micelles elicited opposite effects on the immune response in light of the chain length therefore to show an optimized poly(sarcosine) chain length existing between 33mer and 55mer to suppress the accelerated blood clearance phenomenon associated with polymeric micelles.

Actin-myosin contractility is responsible for the reduced viability of dissociated human embryonic stem cells.

PubMed

Chen, Guokai; Hou, Zhonggang; Gulbranson, Daniel R; Thomson, James A

2010-08-06

Human ESCs are the pluripotent precursor of the three embryonic germ layers. Human ESCs exhibit basal-apical polarity, junctional complexes, integrin-dependent matrix adhesion, and E-cadherin-dependent cell-cell adhesion, all characteristics shared by the epiblast epithelium of the intact mammalian embryo. After disruption of epithelial structures, programmed cell death is commonly observed. If individualized human ESCs are prevented from reattaching and forming colonies, their viability is significantly reduced. Here, we show that actin-myosin contraction is a critical effector of the cell death response to human ESC dissociation. Inhibition of myosin heavy chain ATPase, downregulation of myosin heavy chain, and downregulation of myosin light chain all increase survival and cloning efficiency of individualized human ESCs. ROCK inhibition decreases phosphorylation of myosin light chain, suggesting that inhibition of actin-myosin contraction is also the mechanism through which ROCK inhibitors increase cloning efficiency of human ESCs. Copyright 2010 Elsevier Inc. All rights reserved.

Kepler Uniform Modeling of KOIs: MCMC Notes for Data Release 25

NASA Technical Reports Server (NTRS)

Hoffman, Kelsey L.; Rowe, Jason F.

2017-01-01

This document describes data products related to the reported planetary parameters and uncertainties for the Kepler Objects of Interest (KOIs) based on a Markov-Chain-Monte-Carlo (MCMC) analysis. Reported parameters, uncertainties and data products can be found at the NASA Exoplanet Archive . The codes used for this data analysis are available on the Github website (Rowe 2016). The relevant paper for details of the calculations is Rowe et al. (2015). The main differences between the model fits discussed here and those in the DR24 catalogue are that the DR25 light curves were used in the analysis, our processing of the MAST light curves took into account different data flags, the number of chains calculated was doubled to 200 000, and the parameters which are reported are based on a damped least-squares fit, instead of the median value from the Markov chain or the chain with the lowest 2 as reported in the past.

A general framework to learn surrogate relevance criterion for atlas based image segmentation

NASA Astrophysics Data System (ADS)

Zhao, Tingting; Ruan, Dan

2016-09-01

Multi-atlas based image segmentation sees great opportunities in the big data era but also faces unprecedented challenges in identifying positive contributors from extensive heterogeneous data. To assess data relevance, image similarity criteria based on various image features widely serve as surrogates for the inaccessible geometric agreement criteria. This paper proposes a general framework to learn image based surrogate relevance criteria to better mimic the behaviors of segmentation based oracle geometric relevance. The validity of its general rationale is verified in the specific context of fusion set selection for image segmentation. More specifically, we first present a unified formulation for surrogate relevance criteria and model the neighborhood relationship among atlases based on the oracle relevance knowledge. Surrogates are then trained to be small for geometrically relevant neighbors and large for irrelevant remotes to the given targets. The proposed surrogate learning framework is verified in corpus callosum segmentation. The learned surrogates demonstrate superiority in inferring the underlying oracle value and selecting relevant fusion set, compared to benchmark surrogates.

Surrogacy: the experiences of surrogate mothers.

PubMed

Jadva, Vasanti; Murray, Clare; Lycett, Emma; MacCallum, Fiona; Golombok, Susan

2003-10-01

This study examined the motivations, experiences and psychological consequences of surrogacy for surrogate mothers. Thirty-four women who had given birth to a surrogate child approximately 1 year previously were interviewed by trained researchers, and the data rated using standardized coding criteria. Information was obtained on: (i) reasons for the woman's decision to become a surrogate mother; (ii) her retrospective view of the relationship with the commissioning couple before the pregnancy, during the pregnancy, and after the birth; (iii) her experiences during and after relinquishing the child; and (iv) how others reacted to her decision to become a surrogate mother. It was found that surrogate mothers do not generally experience major problems in their relationship with the commissioning couple, in handing over the baby, or from the reactions of those around them. The emotional problems experienced by some surrogate mothers in the weeks following the birth appeared to lessen over time. Surrogate mothers do not appear to experience psychological problems as a result of the surrogacy arrangement.

The role of imperfect surrogate endpoint information in drug approval and reimbursement decisions.

PubMed

Bognar, Katalin; Romley, John A; Bae, Jay P; Murray, James; Chou, Jacquelyn W; Lakdawalla, Darius N

2017-01-01

Approval of new drugs is increasingly reliant on "surrogate endpoints," which correlate with but imperfectly predict clinical benefits. Proponents argue surrogate endpoints allow for faster approval, but critics charge they provide inadequate evidence. We develop an economic framework that addresses the value of improvement in the predictive power, or "quality," of surrogate endpoints, and clarifies how quality can influence decisions by regulators, payers, and manufacturers. For example, the framework shows how lower-quality surrogates lead to greater misalignment of incentives between payers and regulators, resulting in more drugs that are approved for use but not covered by payers. Efficient price-negotiation in the marketplace can help align payer incentives for granting access based on surrogates. Higher-quality surrogates increase manufacturer profits and social surplus from early access to new drugs. Since the return on better quality is shared between manufacturers and payers, private incentives to invest in higher-quality surrogates are inefficiently low. Copyright © 2016 The Author(s). Published by Elsevier B.V. All rights reserved.

Absolute Side-chain Structure at Position 13 Is Required for the Inhibitory Activity of Bromein*

PubMed Central

Sawano, Yoriko; Hatano, Ken-ichi; Miyakawa, Takuya; Tanokura, Masaru

2008-01-01

Bromelain isoinhibitor (bromein), a cysteine proteinase inhibitor from pineapple stem, has a unique double-chain structure. The bromein precursor protein includes three homologous inhibitor domains, each containing an interchain peptide between the light and heavy chains. The interchain peptide in the single-chain precursor is immediately processed by bromelain, a target proteinase. In the present study, to clarify the essential inhibitory site of bromein, we constructed 44 kinds of site-directed and deletion mutants and investigated the inhibitory activity of each toward bromelain. As a result, the complete chemical structure of Leu13 in the light chain was revealed to be essential for inhibition. Pro12 prior to the leucine residue was also involved in the inhibitory activity and would control the location of the leucine side chain by the fixed φ dihedral angle of proline. Furthermore, the five-residue length of the interchain peptide was strictly required for the inhibitory activity. On the other hand, no inhibitory activity against bromelain was observed by the substitution of proline for the N terminus residue Thr15 of the interchain peptide. In summary, these mutational analyses of bromein demonstrated that the appropriate position and conformation of Leu13 are absolutely crucial for bromelain inhibition. PMID:18948264

Effectiveness of Biodiversity Surrogates for Conservation Planning: Different Measures of Effectiveness Generate a Kaleidoscope of Variation

PubMed Central

Grantham, Hedley S.; Pressey, Robert L.; Wells, Jessie A.; Beattie, Andrew J.

2010-01-01

Conservation planners represent many aspects of biodiversity by using surrogates with spatial distributions readily observed or quantified, but tests of their effectiveness have produced varied and conflicting results. We identified four factors likely to have a strong influence on the apparent effectiveness of surrogates: (1) the choice of surrogate; (2) differences among study regions, which might be large and unquantified (3) the test method, that is, how effectiveness is quantified, and (4) the test features that the surrogates are intended to represent. Analysis of an unusually rich dataset enabled us, for the first time, to disentangle these factors and to compare their individual and interacting influences. Using two data-rich regions, we estimated effectiveness using five alternative methods: two forms of incidental representation, two forms of species accumulation index and irreplaceability correlation, to assess the performance of ‘forest ecosystems’ and ‘environmental units’ as surrogates for six groups of threatened species—the test features—mammals, birds, reptiles, frogs, plants and all of these combined. Four methods tested the effectiveness of the surrogates by selecting areas for conservation of the surrogates then estimating how effective those areas were at representing test features. One method measured the spatial match between conservation priorities for surrogates and test features. For methods that selected conservation areas, we measured effectiveness using two analytical approaches: (1) when representation targets for the surrogates were achieved (incidental representation), or (2) progressively as areas were selected (species accumulation index). We estimated the spatial correlation of conservation priorities using an index known as summed irreplaceability. In general, the effectiveness of surrogates for our taxa (mostly threatened species) was low, although environmental units tended to be more effective than forest ecosystems. The surrogates were most effective for plants and mammals and least effective for frogs and reptiles. The five testing methods differed in their rankings of effectiveness of the two surrogates in relation to different groups of test features. There were differences between study areas in terms of the effectiveness of surrogates for different test feature groups. Overall, the effectiveness of the surrogates was sensitive to all four factors. This indicates the need for caution in generalizing surrogacy tests. PMID:20644726

Smart management of sample dilution using an artificial neural network to achieve streamlined processes and saving resources: the automated nephelometric testing of serum free light chain as case study.

PubMed

Ialongo, Cristiano; Pieri, Massimo; Bernardini, Sergio

2017-02-01

Saving resources is a paramount issue for the modern laboratory, and new trainable as well as smart technologies can be used to allow the automated instrumentation to manage samples more efficiently in order to achieve streamlined processes. In this regard the serum free light chain (sFLC) testing represents an interesting challenge, as it usually causes using a number of assays before achieving an acceptable result within the analytical range. An artificial neural network based on the multi-layer perceptron (MLP-ANN) was used to infer the starting dilution status of sFLC samples based on the information available through the laboratory information system (LIS). After the learning phase, the MLP-ANN simulation was applied to the nephelometric testing routinely performed in our laboratory on a BN ProSpec® System analyzer (Siemens Helathcare) using the N Latex FLC kit. The MLP-ANN reduced the serum kappa free light chain (κ-FLC) and serum lambda free light chain (λ-FLC) wasted tests by 69.4% and 70.8% with respect to the naïve stepwise dilution scheme used by the automated analyzer, and by 64.9% and 66.9% compared to a "rational" dilution scheme based on a 4-step dilution. Although it was restricted to follow-up samples, the MLP-ANN showed good predictive performance, which alongside the possibility to implement it in any automated system, made it a suitable solution for achieving streamlined laboratory processes and saving resources.

Cerebrospinal fluid and neuroimaging biomarker abnormalities suggest early neurological injury in a subset of individuals during primary HIV infection.

PubMed

Peluso, Michael J; Meyerhoff, Dieter J; Price, Richard W; Peterson, Julia; Lee, Evelyn; Young, Andrew C; Walter, Rudy; Fuchs, Dietmar; Brew, Bruce J; Cinque, Paola; Robertson, Kevin; Hagberg, Lars; Zetterberg, Henrik; Gisslén, Magnus; Spudich, Serena

2013-06-01

Cerebrospinal fluid (CSF) and neuroimaging abnormalities demonstrate neuronal injury during chronic AIDS, but data on these biomarkers during primary human immunodeficiency virus (HIV) infection is limited. We compared CSF concentrations of neurofilament light chain, t-tau, p-tau, amyloid precursor proteins, and amyloid-beta 42 in 92 subjects with primary HIV infection and 25 controls. We examined relationships with disease progression and neuroinflammation, neuropsychological testing, and proton-magnetic resonance spectroscopy (MRS)-based metabolites. Neurofilament light chain was elevated in primary HIV infection compared with controls (P = .0004) and correlated with CSF neopterin (r = 0.38; P = .0005), interferon gamma-induced protein 10 (r = 0.39; P = .002), white blood cells (r = 0.32; P = .004), protein (r = 0.59; P < .0001), and CSF/plasma albumin ratio (r = 0.60; P < .0001). Neurofilament light chain correlated with decreased N-acteylaspartate/creatine and glutamate/creatine in the anterior cingulate (r = -0.35, P = .02; r = -0.40, P = .009, respectively), frontal white matter (r = -0.43, P = .003; r = -0.30, P = .048, respectively), and parietal gray matter (r = -0.43, P = .003; r = -0.47, P = .001, respectively). Beta-amyloid was elevated in the primary infection group (P = .0005) and correlated with time infected (r = 0.34; P = .003). Neither marker correlated with neuropsychological abnormalities. T-tau and soluble amyloid precursor proteins did not differ between groups. Elevated neurofilament light chain and its correlation with MRS-based metabolites suggest early neuronal injury in a subset of participants with primary HIV infection through mechanisms involving central nervous system inflammation.

The Novel Zinc Finger Protein dASCIZ Regulates Mitosis in Drosophila via an Essential Role in Dynein Light-Chain Expression

PubMed Central

Zaytseva, Olga; Tenis, Nora; Mitchell, Naomi; Kanno, Shin-ichiro; Yasui, Akira; Heierhorst, Jörg; Quinn, Leonie M

2014-01-01

The essential zinc finger protein ASCIZ (also known as ATMIN, ZNF822) plays critical roles during lung organogenesis and B cell development in mice, where it regulates the expression of dynein light chain (DYNLL1/LC8), but its functions in other species including invertebrates are largely unknown. Here we report the identification of the Drosophila ortholog of ASCIZ (dASCIZ) and show that loss of dASCIZ function leads to pronounced mitotic delays with centrosome and spindle positioning defects during development, reminiscent of impaired dynein motor functions. Interestingly, similar mitotic and developmental defects were observed upon knockdown of the DYNLL/LC8-type dynein light chain Cutup (Ctp), and dASCIZ loss-of-function phenotypes could be suppressed by ectopic Ctp expression. Consistent with a genetic function of dASCIZ upstream of Ctp, we show that loss of dASCIZ led to reduced endogenous Ctp mRNA and protein levels and dramatically reduced Ctp–LacZ reporter gene activity in vivo, indicating that dASCIZ regulates development and mitosis as a Ctp transcription factor. We speculate that the more severe mitotic defects in the absence of ASCIZ in flies compared to mice may be due to redundancy with a second, ASCIZ-independent, Dynll2 gene in mammals in contrast to a single Ctp gene in Drosophila. Altogether, our data demonstrate that ASCIZ is an evolutionary highly conserved transcriptional regulator of dynein light-chain levels and a novel regulator of mitosis in flies. PMID:24336747

Systematic review: the effect on surrogates of making treatment decisions for others.

PubMed

Wendler, David; Rid, Annette

2011-03-01

Clinical practice relies on surrogates to make or help to make treatment decisions for incapacitated adults; however, the effect of this practice on surrogates has not been evaluated. To assess the effect on surrogates of making treatment decisions for adults who cannot make their own decisions. Empirical studies published in English and listed in MEDLINE, EMBASE, CINAHL, BIOETHICSLINE, PsycINFO, or Scopus before 1 July 2010. Eligible studies provided quantitative or qualitative empirical data, by evaluating surrogates, regarding the effect on surrogates of making treatment decisions for an incapacitated adult. Information on study location, number and type of surrogates, timing of data collection, type of decisions, patient setting, methods, main findings, and limitations. 40 studies, 29 using qualitative and 11 using quantitative methods, provided data on 2854 surrogates, more than one half of whom were family members of the patient. Most surrogates were surveyed several months to years after making treatment decisions, the majority of which were end-of-life decisions. The quantitative studies found that at least one third of surrogates experienced a negative emotional burden as the result of making treatment decisions. The qualitative studies reported that many or most surrogates experienced negative emotional burden. The negative effects on surrogates were often substantial and typically lasted months or, in some cases, years. The most common negative effects cited by surrogates were stress, guilt over the decisions they made, and doubt regarding whether they had made the right decisions. Nine of the 40 studies also reported beneficial effects on a few surrogates, the most common of which were supporting the patient and feeling a sense of satisfaction. Knowing which treatment is consistent with the patient's preferences was frequently cited as reducing the negative effect on surrogates. Thirty-two of the 40 articles reported data collected in the United States. Because the study populations were relatively homogenous, it is unclear whether the findings apply to other groups. In some cases, the effect of making treatment decisions could not be isolated from that of other stressors, such as grief or prognostic uncertainty. Nine of the studies had a response rate less than 50%, and 9 did not report a response rate. Many of the studies had a substantial interval between the treatment decisions and data collection. Making treatment decisions has a negative emotional effect on at least one third of surrogates, which is often substantial and typically lasts months (or sometimes years). Future research should evaluate ways to reduce this burden, including methods to identify which treatment options are consistent with the patient's preferences. National Institutes of Health.

Challenge of surrogate endpoints.

PubMed

Furgerson, James L; Hannah, William N; Thompson, Jennifer C

2012-03-01

Surrogate endpoints are biomarkers that are intended to substitute for clinical endpoints. They have been used to find novel therapeutic targets, improve the statistical power and shorten the duration of clinical trials, and control the cost of conducting research studies. The more generalized use of surrogate endpoints in clinical decision making can be hazardous and should be undertaken with great caution. This article reviews prior work with surrogate endpoints and highlights caveats and lessons learned from studies using surrogate endpoints.

Statistical evaluation of surrogate endpoints with examples from cancer clinical trials.

PubMed

Buyse, Marc; Molenberghs, Geert; Paoletti, Xavier; Oba, Koji; Alonso, Ariel; Van der Elst, Wim; Burzykowski, Tomasz

2016-01-01

A surrogate endpoint is intended to replace a clinical endpoint for the evaluation of new treatments when it can be measured more cheaply, more conveniently, more frequently, or earlier than that clinical endpoint. A surrogate endpoint is expected to predict clinical benefit, harm, or lack of these. Besides the biological plausibility of a surrogate, a quantitative assessment of the strength of evidence for surrogacy requires the demonstration of the prognostic value of the surrogate for the clinical outcome, and evidence that treatment effects on the surrogate reliably predict treatment effects on the clinical outcome. We focus on these two conditions, and outline the statistical approaches that have been proposed to assess the extent to which these conditions are fulfilled. When data are available from a single trial, one can assess the "individual level association" between the surrogate and the true endpoint. When data are available from several trials, one can additionally assess the "trial level association" between the treatment effect on the surrogate and the treatment effect on the true endpoint. In the latter case, the "surrogate threshold effect" can be estimated as the minimum effect on the surrogate endpoint that predicts a statistically significant effect on the clinical endpoint. All these concepts are discussed in the context of randomized clinical trials in oncology, and illustrated with two meta-analyses in gastric cancer. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The long-term experiences of surrogates: relationships and contact with surrogacy families in genetic and gestational surrogacy arrangements.

PubMed

Imrie, Susan; Jadva, Vasanti

2014-10-01

This study examined the contact arrangements and relationships between surrogates and surrogacy families and whether these outcomes differed according to the type of surrogacy undertaken. Surrogates' motivations for carrying out multiple surrogacy arrangements were also examined, and surrogates' psychological health was assessed. Semi-structured interviews were administered to 34 women who had given birth to a child conceived through surrogacy approximately 7 years prior to interview. Some surrogates had carried out multiple surrogacy arrangements, and data were collected on the frequency, type of contact, and surrogate's feelings about the level of contact in each surrogacy arrangement, the surrogate's relationship with each child and parent, and her experience of, and motivation for, each surrogacy. Questionnaire measures of psychological health were administered. Surrogates had completed a total of 102 surrogacy arrangements and remained in contact with the majority of families, and reported positive relationships in most cases. Surrogates were happy with their level of contact in the majority of arrangements and most were viewed as positive experiences. Few differences were found according to surrogacy type. The primary motivation given for multiple surrogacy arrangements was to help couples have a sibling for an existing child. Most surrogates showed no psychological health problems at the time of data collection. Copyright © 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

White Polymer Light-Emitting Diodes Based on Exciplex Electroluminescence from Polymer Blends and a Single Polymer.

PubMed

Liang, Junfei; Zhao, Sen; Jiang, Xiao-Fang; Guo, Ting; Yip, Hin-Lap; Ying, Lei; Huang, Fei; Yang, Wei; Cao, Yong

2016-03-09

In this Article, we designed and synthesized a series of polyfluorene derivatives, which consist of the electron-rich 4,4'-(9-alkyl-carbazole-3,6-diyl)bis(N,N-diphenylaniline) (TPA-Cz) in the side chain and the electron-deficient dibenzothiophene-5,5-dioxide (SO) unit in the main chain. The resulting copolymer PF-T25 that did not comprise the SO unit exhibited blue light-emission with the Commission Internationale de L'Eclairage coordinates of (0.16, 0.10). However, by physically blending PF-T25 with a blue light-emitting SO-based oligomer, a novel low-energy emission correlated to exciplex emerged due to the appropriate energy level alignment of TPA-Cz and the SO-based oligomers, which showed extended exciton lifetime as confirmed by time-resolved photoluminescent spectroscopy. The low-energy emission was also identified in copolymers consisting of SO unit in the main chain, which can effectively compensate for the high-energy emission to produce binary white light-emission. Polymer light-emitting diodes based on the exciplex-type single greenish-white polymer exhibit the peak luminous efficiency of 2.34 cd A(-1) and the maximum brightness of 12 410 cd m(-2), with Commission Internationale de L'Eclairage color coordinates (0.27, 0.39). The device based on such polymer showed much better electroluminescent stability than those based on blending films. These observations indicated that developing a single polymer with the generated exciplex emission can be a novel and effective molecular design strategy toward highly stable and efficient white polymer light-emitting diodes.

The Limits of Surrogates' Moral Authority and Physician Professionalism: Can the Paradigm of Palliative Sedation Be Instructive?

PubMed

Berger, Jeffrey T

2017-01-01

With narrow exception, physicians' treatment of incapacitated patients requires the consent of health surrogates. Although the decision-making authority of surrogates is appropriately broad, their moral authority is not without limits. Discerning these bounds is particularly germane to ethically complex treatments and has important implications for the welfare of patients, for the professional integrity of clinicians, and, in fact, for the welfare of surrogates. Palliative sedation is one such complex treatment; as such, it provides a valuable model for analyzing the scope of surrogates' moral authority. Guidelines for palliative sedation that present it as a "last-resort" treatment for severe and intractable suffering yet require surrogate consent in order to offer it are ethically untenable, precisely because the moral limits of surrogate authority have not been considered. © 2017 The Hastings Center.

Synthesis of α,β-unsaturated aldehydes as potential substrates for bacterial luciferases.

PubMed

Brodl, Eveline; Ivkovic, Jakov; Tabib, Chaitanya R; Breinbauer, Rolf; Macheroux, Peter

2017-02-15

Bacterial luciferase catalyzes the monooxygenation of long-chain aldehydes such as tetradecanal to the corresponding acid accompanied by light emission with a maximum at 490nm. In this study even numbered aldehydes with eight, ten, twelve and fourteen carbon atoms were compared with analogs having a double bond at the α,β-position. These α,β-unsaturated aldehydes were synthesized in three steps and were examined as potential substrates in vitro. The luciferase of Photobacterium leiognathi was found to convert these analogs and showed a reduced but significant bioluminescence activity compared to tetradecanal. This study showed the trend that aldehydes, both saturated and unsaturated, with longer chain lengths had higher activity in terms of bioluminescence than shorter chain lengths. The maximal light intensity of (E)-tetradec-2-enal was approximately half with luciferase of P. leiognathi, compared to tetradecanal. Luciferases of Vibrio harveyi and Aliivibrio fisheri accepted these newly synthesized substrates but light emission dropped drastically compared to saturated aldehydes. The onset and the decay rate of bioluminescence were much slower, when using unsaturated substrates, indicating a kinetic effect. As a result the duration of the light emission is doubled. These results suggest that the substrate scope of bacterial luciferases is broader than previously reported. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Bayesian Adaptive Trial Design for a Newly Validated Surrogate Endpoint

PubMed Central

Renfro, Lindsay A.; Carlin, Bradley P.; Sargent, Daniel J.

2011-01-01

Summary The evaluation of surrogate endpoints for primary use in future clinical trials is an increasingly important research area, due to demands for more efficient trials coupled with recent regulatory acceptance of some surrogates as ‘valid.’ However, little consideration has been given to how a trial which utilizes a newly-validated surrogate endpoint as its primary endpoint might be appropriately designed. We propose a novel Bayesian adaptive trial design that allows the new surrogate endpoint to play a dominant role in assessing the effect of an intervention, while remaining realistically cautious about its use. By incorporating multi-trial historical information on the validated relationship between the surrogate and clinical endpoints, then subsequently evaluating accumulating data against this relationship as the new trial progresses, we adaptively guard against an erroneous assessment of treatment based upon a truly invalid surrogate. When the joint outcomes in the new trial seem plausible given similar historical trials, we proceed with the surrogate endpoint as the primary endpoint, and do so adaptively–perhaps stopping the trial for early success or inferiority of the experimental treatment, or for futility. Otherwise, we discard the surrogate and switch adaptive determinations to the original primary endpoint. We use simulation to test the operating characteristics of this new design compared to a standard O’Brien-Fleming approach, as well as the ability of our design to discriminate trustworthy from untrustworthy surrogates in hypothetical future trials. Furthermore, we investigate possible benefits using patient-level data from 18 adjuvant therapy trials in colon cancer, where disease-free survival is considered a newly-validated surrogate endpoint for overall survival. PMID:21838811

Surrogate Plant Data Base : Volume 1. Introduction, Appendix A : The Development of Surrogate Plant Data ; Appendix B : Application of the Surrogate .

DOT National Transportation Integrated Search

1983-03-01

This four volume report consists of a data base describing "surrogate" automobile and truck manufacturing plants developed as part of a methodology for evaluating capital investment requirements in new manufacturing facilities to build new fleets of ...

26 CFR 1.7874-2T - Surrogate foreign corporation (temporary).

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 13 2012-04-01 2012-04-01 false Surrogate foreign corporation (temporary). 1... Surrogate foreign corporation (temporary). (a) Scope. This section provides rules for determining whether a foreign corporation shall be treated as a surrogate foreign corporation under section 7874(a)(2)(B...

26 CFR 1.7874-2T - Surrogate foreign corporation (temporary).

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 13 2011-04-01 2011-04-01 false Surrogate foreign corporation (temporary). 1... Surrogate foreign corporation (temporary). (a) Scope. This section provides rules for determining whether a foreign corporation shall be treated as a surrogate foreign corporation under section 7874(a)(2)(B...

34 CFR 300.519 - Surrogate parents.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Surrogate parent responsibilities. The surrogate parent may represent the child in all matters relating to... DISABILITIES Procedural Safeguards Due Process Procedures for Parents and Children § 300.519 Surrogate parents..., cannot locate a parent; (3) The child is a ward of the State under the laws of that State; or (4) The...

34 CFR 300.519 - Surrogate parents.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Surrogate parent responsibilities. The surrogate parent may represent the child in all matters relating to... DISABILITIES Procedural Safeguards Due Process Procedures for Parents and Children § 300.519 Surrogate parents..., cannot locate a parent; (3) The child is a ward of the State under the laws of that State; or (4) The...

34 CFR 300.519 - Surrogate parents.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Surrogate parent responsibilities. The surrogate parent may represent the child in all matters relating to... DISABILITIES Procedural Safeguards Due Process Procedures for Parents and Children § 300.519 Surrogate parents..., cannot locate a parent; (3) The child is a ward of the State under the laws of that State; or (4) The...

34 CFR 300.519 - Surrogate parents.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Surrogate parent responsibilities. The surrogate parent may represent the child in all matters relating to... DISABILITIES Procedural Safeguards Due Process Procedures for Parents and Children § 300.519 Surrogate parents..., cannot locate a parent; (3) The child is a ward of the State under the laws of that State; or (4) The...

34 CFR 300.519 - Surrogate parents.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Surrogate parent responsibilities. The surrogate parent may represent the child in all matters relating to... DISABILITIES Procedural Safeguards Due Process Procedures for Parents and Children § 300.519 Surrogate parents..., cannot locate a parent; (3) The child is a ward of the State under the laws of that State; or (4) The...

Rotavirus Virus-Like Particles as Surrogates in Environmental Persistence and Inactivation Studies

PubMed Central

Caballero, Santiago; Abad, F. Xavier; Loisy, Fabienne; Le Guyader, Françoise S.; Cohen, Jean; Pintó, Rosa M.; Bosch, Albert

2004-01-01

Virus-like particles (VLPs) with the full-length VP2 and VP6 rotavirus capsid proteins, produced in the baculovirus expression system, have been evaluated as surrogates of human rotavirus in different environmental scenarios. Green fluorescent protein-labeled VLPs (GFP-VLPs) and particles enclosing a heterologous RNA (pseudoviruses), whose stability may be monitored by flow cytometry and antigen capture reverse transcription-PCR, respectively, were used. After 1 month in seawater at 20°C, no significant differences were observed between the behaviors of GFP-VLPs and of infectious rotavirus, whereas pseudovirus particles showed a higher decay rate. In the presence of 1 mg of free chlorine (FC)/liter both tracers persisted longer in freshwater at 20°C than infectious viruses, whereas in the presence of 0.2 mg of FC/liter no differences were observed between tracers and infectious rotavirus at short contact times. However, from 30 min of contact with FC onward, the decay of infectious rotavirus was higher than that of recombinant particles. The predicted Ct value for a 90% reduction of GFP-VLPs or pseudoviruses induces a 99.99% inactivation of infectious rotavirus. Both tracers were more resistant to UV light irradiation than infectious rotavirus in fresh and marine water. The effect of UV exposure was more pronounced on pseudovirus than in GFP-VLPs. In all types of water, the UV dose to induce a 90% reduction of pseudovirus ensures a 99.99% inactivation of infectious rotavirus. Recombinant virus surrogates open new possibilities for the systematic validation of virus removal practices in actual field situations where pathogenic agents cannot be introduced. PMID:15240262

Increasing evidence of mechanical force as a functional regulator in smooth muscle myosin light chain kinase

PubMed Central

Baumann, Fabian; Bauer, Magnus Sebastian; Rees, Martin; Alexandrovich, Alexander; Gautel, Mathias; Pippig, Diana Angela; Gaub, Hermann Eduard

2017-01-01

Mechanosensitive proteins are key players in cytoskeletal remodeling, muscle contraction, cell migration and differentiation processes. Smooth muscle myosin light chain kinase (smMLCK) is a member of a diverse group of serine/threonine kinases that feature cytoskeletal association. Its catalytic activity is triggered by a conformational change upon Ca2+/calmodulin (Ca2+/CaM) binding. Due to its significant homology with the force-activated titin kinase, smMLCK is suspected to be also regulatable by mechanical stress. In this study, a CaM-independent activation mechanism for smMLCK by mechanical release of the inhibitory elements is investigated via high throughput AFM single-molecule force spectroscopy. The characteristic pattern of transitions between different smMLCK states and their variations in the presence of different substrates and ligands are presented. Interaction between kinase domain and regulatory light chain (RLC) substrate is identified in the absence of CaM, indicating restored substrate-binding capability due to mechanically induced removal of the auto-inhibitory regulatory region. DOI: http://dx.doi.org/10.7554/eLife.26473.001 PMID:28696205

Precise Protein Photolithography (P3): High Performance Biopatterning Using Silk Fibroin Light Chain as the Resist

PubMed Central

Liu, Wanpeng; Zhou, Zhitao; Zhang, Shaoqing; Shi, Zhifeng; Tabarini, Justin; Lee, Woonsoo; Zhang, Yeshun; Gilbert Corder, S. N.; Li, Xinxin; Dong, Fei; Cheng, Liang; Liu, Mengkun; Kaplan, David L.; Omenetto, Fiorenzo G.

2017-01-01

Precise patterning of biomaterials has widespread applications, including drug release, degradable implants, tissue engineering, and regenerative medicine. Patterning of protein‐based microstructures using UV‐photolithography has been demonstrated using protein as the resist material. The Achilles heel of existing protein‐based biophotoresists is the inevitable wide molecular weight distribution during the protein extraction/regeneration process, hindering their practical uses in the semiconductor industry where reliability and repeatability are paramount. A wafer‐scale high resolution patterning of bio‐microstructures using well‐defined silk fibroin light chain as the resist material is presented showing unprecedent performances. The lithographic and etching performance of silk fibroin light chain resists are evaluated systematically and the underlying mechanisms are thoroughly discussed. The micropatterned silk structures are tested as cellular substrates for the successful spatial guidance of fetal neural stems cells seeded on the patterned substrates. The enhanced patterning resolution, the improved etch resistance, and the inherent biocompatibility of such protein‐based photoresist provide new opportunities in fabricating large scale biocompatible functional microstructures. PMID:28932678

The invasion mode of GH(3) cells is conditioned by collagen subtype, and its efficiency depends on cell-cell adhesion.

PubMed

Azorín, Erika; Solano-Agama, Carmen; Mendoza-Garrido, M Eugenia

2012-12-15

The adaptation of GH(3) cells to different microenvironments is a consequence of a partial compromise with the tumor phenotype. A collagen type IV enriched microenvironment favors an invasive phenotype and increases the substrate adhesion capacity, whereas it decreases the phosphorylation of the regulatory myosin light chain and the aggregation capacity. In contrast, the higher internal tension and increased aggregation capacity induced by collagen type I/III are factors that reduce the invasion rate. Our results show, for the first time, the importance of collagen subtypes in determining the migratory strategy: collagen I/III favors mesenchymal-like motility, whereas collagen type IV induces an ameboid-type displacement. The reciprocal modulation of the myosin light chain kinase and the Rho-kinase determines the invasive capacity through changes in tissue cohesion, extracellular matrix affinity, regulatory myosin light chain phosphorylation and spatial distribution. The collagen subtype determines which of the mechano-transduction signaling pathways will regulate the tensional homeostasis and affect the invasion ability as well as the preferred migration strategy of the cells. Copyright © 2012 Elsevier Inc. All rights reserved.

Antibody Light-Chain-Restricted Recognition of the Site of Immune Pressure in the RV144 HIV-1 Vaccine Trial Is Phylogenetically Conserved

DOE PAGES

Wiehe, Kevin; Easterhoff, David; Luo, Kan; ...

2014-11-29

In HIV-1, the ability to mount antibody responses to conserved, neutralizing epitopes is critical for protection. Here we have studied the light chain usage of human and rhesus macaque antibodies targeted to a dominant region of the HIV-1 envelope second variable (V2) region involving lysine (K) 169, the site of immune pressure in the RV144 vaccine efficacy trial. We found that humans and rhesus macaques used orthologous lambda variable gene segments encoding a glutamic acid-aspartic acid (ED) motif for K169 recognition. Structure determination of an unmutated ancestor antibody demonstrated that the V2 binding site was preconfigured for ED motif-mediated recognitionmore » prior to maturation. Thus, light chain usage for recognition of the site of immune pressure in the RV144 trial is highly conserved across species. In conclusion, these data indicate that the HIV-1 K169-recognizing ED motif has persisted over the diversification between rhesus macaques and humans, suggesting an evolutionary advantage of this antibody recognition mode.« less

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

McWilliams-Koeppen, Helen P.; Foster, James S.; Hackenbrack, Nicole

Light chain (AL) amyloidosis is the most common form of systemic amyloid disease, and cardiomyopathy is a dire consequence, resulting in an extremely poor prognosis. AL is characterized by the production of monoclonal free light chains that deposit as amyloid fibrils principally in the heart, liver, and kidneys causing organ dysfunction. We have studied the effects of amyloid fibrils, produced from recombinant λ6 light chain variable domains, on metabolic activity of human cardiomyocytes. The data indicate that fibrils at 0.1 μM, but not monomer, significantly decrease the enzymatic activity of cellular NAD(P)H-dependent oxidoreductase, without causing significant cell death. The presencemore » of amyloid fibrils did not affect ATP levels; however, oxygen consumption was increased and reactive oxygen species were detected. Confocal fluorescence microscopy showed that fibrils bound to and remained at the cell surface with little fibril internalization. Ultimately, these data indicate that AL amyloid fibrils severely impair cardiomyocyte metabolism in a dose dependent manner. These data suggest that effective therapeutic intervention for these patients should include methods for removing potentially toxic amyloid fibrils.« less

Inhibiting Myosin Light Chain Kinase Induces Apoptosis In Vitro and In Vivo

PubMed Central

Fazal, Fabeha; Gu, Lianzhi; Ihnatovych, Ivanna; Han, YooJeong; Hu, WenYang; Antic, Nenad; Carreira, Fernando; Blomquist, James F.; Hope, Thomas J.; Ucker, David S.; de Lanerolle, Primal

2005-01-01

Previous short-term studies have correlated an increase in the phosphorylation of the 20-kDa light chain of myosin II (MLC20) with blebbing in apoptotic cells. We have found that this increase in MLC20 phosphorylation is rapidly followed by MLC20 dephosphorylation when cells are stimulated with various apoptotic agents. MLC20 dephosphorylation is not a consequence of apoptosis because MLC20 dephosphorylation precedes caspase activation when cells are stimulated with a proapoptotic agent or when myosin light chain kinase (MLCK) is inhibited pharmacologically or by microinjecting an inhibitory antibody to MLCK. Moreover, blocking caspase activation increased cell survival when MLCK is inhibited or when cells are treated with tumor necrosis factor alpha. Depolymerizing actin filaments or detaching cells, processes that destabilize the cytoskeleton, or inhibiting myosin ATPase activity also resulted in MLC20 dephosphorylation and cell death. In vivo experiments showed that inhibiting MLCK increased the number of apoptotic cells and retarded the growth of mammary cancer cells in mice. Thus, MLC20 dephosphorylation occurs during physiological cell death and prolonged MLC20 dephosphorylation can trigger apoptosis. PMID:15988034

Antibody Light-Chain-Restricted Recognition of the Site of Immune Pressure in the RV144 HIV-1 Vaccine Trial Is Phylogenetically Conserved

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

Wiehe, Kevin; Easterhoff, David; Luo, Kan

In HIV-1, the ability to mount antibody responses to conserved, neutralizing epitopes is critical for protection. Here we have studied the light chain usage of human and rhesus macaque antibodies targeted to a dominant region of the HIV-1 envelope second variable (V2) region involving lysine (K) 169, the site of immune pressure in the RV144 vaccine efficacy trial. We found that humans and rhesus macaques used orthologous lambda variable gene segments encoding a glutamic acid-aspartic acid (ED) motif for K169 recognition. Structure determination of an unmutated ancestor antibody demonstrated that the V2 binding site was preconfigured for ED motif-mediated recognitionmore » prior to maturation. Thus, light chain usage for recognition of the site of immune pressure in the RV144 trial is highly conserved across species. In conclusion, these data indicate that the HIV-1 K169-recognizing ED motif has persisted over the diversification between rhesus macaques and humans, suggesting an evolutionary advantage of this antibody recognition mode.« less

Immunoglobulin kappa light chain gene promoter and enhancer are not responsible for B-cell restricted gene rearrangement.

PubMed Central

Goodhardt, M; Babinet, C; Lutfalla, G; Kallenbach, S; Cavelier, P; Rougeon, F

1989-01-01

We have produced transgenic mice which synthesize chimeric mouse-rabbit immunoglobulin (Ig) kappa light chains following in vivo recombination of an injected unrearranged kappa gene. The exogenous gene construct contained a mouse germ-line kappa variable (V kappa) gene segment, the mouse germ-line joining (J kappa) locus including the enhancer, and the rabbit b9 constant (C kappa) region. A high level of V-J recombination of the kappa transgene was observed in spleen of the transgenic mice. Surprisingly, a particularly high degree of variability in the exact site of recombination and the presence of non germ-line encoded nucleotides (N-regions) were found at the V-J junction of the rearranged kappa transgene. Furthermore, unlike endogenous kappa genes, rearrangement of the exogenous gene occurred in T-cells of the transgenic mice. These results show that additional sequences, other than the heptamer-nonamer signal sequences and the promoter and enhancer elements, are required to obtain stage- and lineage- specific regulation of Ig kappa light chain gene rearrangement in vivo. Images PMID:2508061

New Proof-of-Concept in Viral Inactivation: Virucidal Efficacy of 405 nm Light Against Feline Calicivirus as a Model for Norovirus Decontamination.

PubMed

Tomb, Rachael M; Maclean, Michelle; Coia, John E; Graham, Elizabeth; McDonald, Michael; Atreya, Chintamani D; MacGregor, Scott J; Anderson, John G

2017-06-01

The requirement for novel decontamination technologies for use in hospitals is ever present. One such system uses 405 nm visible light to inactivate microorganisms via ROS-generated oxidative damage. Although effective for bacterial and fungal inactivation, little is known about the virucidal effects of 405 nm light. Norovirus (NoV) gastroenteritis outbreaks often occur in the clinical setting, and this study was designed to investigate potential inactivation effects of 405 nm light on the NoV surrogate, feline calicivirus (FCV). FCV was exposed to 405 nm light whilst suspended in minimal and organically-rich media to establish the virucidal efficacy and the effect biologically-relevant material may play in viral susceptibility. Antiviral activity was successfully demonstrated with a 4 Log 10 (99.99%) reduction in infectivity when suspended in minimal media evident after a dose of 2.8 kJ cm -2 . FCV exposed in artificial faeces, artificial saliva, blood plasma and other organically rich media exhibited an equivalent level of inactivation using between 50-85% less dose of the light, indicating enhanced inactivation when the virus is present in organically-rich biologically-relevant media. Further research in this area could aid in the development of 405 nm light technology for effective NoV decontamination within the hospital environment.

Antifreeze (glyco)protein mimetic behavior of poly(vinyl alcohol): detailed structure ice recrystallization inhibition activity study.

PubMed

Congdon, Thomas; Notman, Rebecca; Gibson, Matthew I

2013-05-13

This manuscript reports a detailed study on the ability of poly(vinyl alcohol) to act as a biomimetic surrogate for antifreeze(glyco)proteins, with a focus on the specific property of ice-recrystallization inhibition (IRI). Despite over 40 years of study, the underlying mechanisms that govern the action of biological antifreezes are still poorly understood, which is in part due to their limited availability and challenging synthesis. Poly(vinyl alcohol) (PVA) has been shown to display remarkable ice recrystallization inhibition activity despite its major structural differences to native antifreeze proteins. Here, controlled radical polymerization is used to synthesize well-defined PVA, which has enabled us to obtain the first quantitative structure-activity relationships, to probe the role of molecular weight and comonomers on IRI activity. Crucially, it was found that IRI activity is "switched on" when the polymer chain length increases from 10 and 20 repeat units. Substitution of the polymer side chains with hydrophilic or hydrophobic units was found to diminish activity. Hydrophobic modifications to the backbone were slightly more tolerated than side chain modifications, which implies an unbroken sequence of hydroxyl units is necessary for activity. These results highlight that, although hydrophobic domains are key components of IRI activity, the random inclusion of addition hydrophobic units does not guarantee an increase in activity and that the actual polymer conformation is important.

Analysis of correlated domain motions in IgG light chain reveals possible mechanisms of immunological signal transduction.

PubMed

Król, Marcin; Roterman, Irena; Piekarska, Barbara; Konieczny, Leszek; Rybarska, Janina; Stopa, Barbara; Spólnik, Paweł

2005-05-15

It was shown experimentally that binding of a micelle composed of Congo red molecules to immunological complexes leads to the enhanced stability of the latter, and simultaneously prevents binding of a complement molecule (C1q). The dye binds in a cavity created by the removal of N-terminal polypeptide chain, as observed experimentally in a model system-immunoglobulin G (IgG) light chain dimer. Molecular Dynamics (MD) simulations of three forms of IgG light chain dimer, with and without the dye, were performed to investigate the role of N-terminal fragment and self-assembled ligand in coupling between V and C domains. Root-mean-square distance (RMSD) time profiles show that removal of N-terminal fragment leads to destabilization of V domain. A micelle composed of four self-assembled dye molecules stabilizes and fixes the domain. Analysis of root-mean-square fluctuation (RMSF) values and dynamic cross-correlation matrices (DCCM) reveals that removal of N-terminal fragment results in complete decoupling between V and C domains. Binding of self-assembled Congo red molecules improves the coupling, albeit slightly. The disruption of a small beta-sheet composed of N- and C-terminal fragments of the domain (NC sheet) is the most likely reason for the decoupling. Self-assembled ligand, bound in the place originally occupied by N-terminal fragment, is not able to take over the function of the beta-sheet. Lack of correlation of motions between residues in V and C domains denotes that light chain-Congo red complexes have hampered ability to transmit conformational changes between domains. This is a likely explanation of the lack of complement binding by immunological complexes, which bind Congo red, and supports the idea that the NC sheet is the key structural fragment taking part in immunological signal transduction. Copyright 2005 Wiley-Liss, Inc.

Monoclonal antibodies against loggerhead sea turtle, Caretta caretta, IgY isoforms reveal differential contributions to antibody titers and relatedness among other sea turtles.

PubMed

Rodgers, Maria L; Rice, Charles D

2018-05-19

Serum from loggerhead sea turtles, Caretta caretta, was collected from the southeast Atlantic Ocean during routine summer monitoring studies in 2017. Serum immunoglobulin IgY was purified and used to develop IgY isoform-specific monoclonal antibodies (mAb). mAb LH12 was developed against the 66 kDa heavy chain of IgY, mAb LH1 was developed against the truncated heavy chain of approximately 37 kDA, and mAb LH9 was developed against the 23 kDa light chains. mAb LH9 reacts with the light chains of all sea turtles, mAb LH12 reacts with the long heavy chain of all sea turtles within the family Cheloniidae, and mAb LH1 reacts with the truncated form of IgY in both olive and Kemp's ridley turtles. Circulating IgY antibodies against three different marine bacterial pathogens were determined in 16 loggerhead samples using these mAbs. mAb LH12 detects higher titers than mAb LH1, and mAb LH9 detects the highest titers. Copyright © 2018 Elsevier Ltd. All rights reserved.

A surrogate model for thermal characteristics of stratospheric airship

NASA Astrophysics Data System (ADS)

Zhao, Da; Liu, Dongxu; Zhu, Ming

2018-06-01

A simple and accurate surrogate model is extremely needed to reduce the analysis complexity of thermal characteristics for a stratospheric airship. In this paper, a surrogate model based on the Least Squares Support Vector Regression (LSSVR) is proposed. The Gravitational Search Algorithm (GSA) is used to optimize hyper parameters. A novel framework consisting of a preprocessing classifier and two regression models is designed to train the surrogate model. Various temperature datasets of the airship envelope and the internal gas are obtained by a three-dimensional transient model for thermal characteristics. Using these thermal datasets, two-factor and multi-factor surrogate models are trained and several comparison simulations are conducted. Results illustrate that the surrogate models based on LSSVR-GSA have good fitting and generalization abilities. The pre-treated classification strategy proposed in this paper plays a significant role in improving the accuracy of the surrogate model.

Diesel surrogate fuels for engine testing and chemical-kinetic modeling: Compositions and properties

DOE PAGES

Mueller, Charles J.; Cannella, William J.; Bays, J. Timothy; ...

2016-01-07

The primary objectives of this work were to formulate, blend, and characterize a set of four ultralow-sulfur diesel surrogate fuels in quantities sufficient to enable their study in single-cylinder-engine and combustion-vessel experiments. The surrogate fuels feature increasing levels of compositional accuracy (i.e., increasing exactness in matching hydrocarbon structural characteristics) relative to the single target diesel fuel upon which the surrogate fuels are based. This approach was taken to assist in determining the minimum level of surrogate-fuel compositional accuracy that is required to adequately emulate the performance characteristics of the target fuel under different combustion modes. For each of the fourmore » surrogate fuels, an approximately 30 L batch was blended, and a number of the physical and chemical properties were measured. In conclusion, this work documents the surrogate-fuel creation process and the results of the property measurements.« less

Diesel Surrogate Fuels for Engine Testing and Chemical-Kinetic Modeling: Compositions and Properties

PubMed Central

Mueller, Charles J.; Cannella, William J.; Bays, J. Timothy; Bruno, Thomas J.; DeFabio, Kathy; Dettman, Heather D.; Gieleciak, Rafal M.; Huber, Marcia L.; Kweon, Chol-Bum; McConnell, Steven S.; Pitz, William J.; Ratcliff, Matthew A.

2016-01-01

The primary objectives of this work were to formulate, blend, and characterize a set of four ultralow-sulfur diesel surrogate fuels in quantities sufficient to enable their study in single-cylinder-engine and combustion-vessel experiments. The surrogate fuels feature increasing levels of compositional accuracy (i.e., increasing exactness in matching hydrocarbon structural characteristics) relative to the single target diesel fuel upon which the surrogate fuels are based. This approach was taken to assist in determining the minimum level of surrogate-fuel compositional accuracy that is required to adequately emulate the performance characteristics of the target fuel under different combustion modes. For each of the four surrogate fuels, an approximately 30 L batch was blended, and a number of the physical and chemical properties were measured. This work documents the surrogate-fuel creation process and the results of the property measurements. PMID:27330248

[Construction of the lentiviral expression vector for anti-p185(erbB2) mouse/human chimeric antibody].

PubMed

Liu, Fang; Li, Li; Zhang, Wei; Wang, Qi

2013-04-01

This research was to construct the lentiviral expression vector for anti- p185(erbB2) mouse/human chimeric antibody and to determine the expression of the chimeric antibody gene in 293T cells transfected with this vector. The genes (vL and vH) coding light and heavy chain of variable regions of anti-p185(erbB2) mAb and the constant regions of human IgG1 (kappa and gamma1) were cloned with PCR method. The target genes were assembled by three-primers PCR method to obtain the chimeric light chain (L) and the chimeric heavy chain (H). Both chains inserted into the down stream and upper stream of IRES gene of the plasmid pVAX1/IRES respectively. We digested the plasmid pVAX1/ H-IRES-L with endoenzyme and subcloned H-IRES-L into the lentiviral vector pWPI. The enzyme digestion and sequence analysis showed that the lentiviral expression vector pWPI/H-IRES-L was constructed correctly. Then, it was transfected into 293T cells and after 48h, GFP protein expression in 293T cells were detected by fluorescent microscope and the chimeric antibody expression was detected by RT-PCR and direct ELISA. The results showed that after 293T cells were transfected with recombination plasmid, both light and heavy chains of the chimeric antibody genes could express together. The chimeric antibody expressed could bind to p185(erbB2) specifically. This research may lay a sound foundation for further study of anti-p185(erbB2) engineered antibody.

Deconstructing the surrogate species concept:a life history approach to the protection of ecosystem services.

USDA-ARS?s Scientific Manuscript database

The use of the surrogate species concept is widespread in environmental risk assessment and in particular the protection of species that provide ecosystem services, yet there are no standard protocols in place for the choice of surrogates. Surrogates are often chosen on the basis of convenience or v...

Deconstructing the surrogate species concept: a life history approach to the protection of ecosystem services

USDA-ARS?s Scientific Manuscript database

The use of the surrogate species concept is widespread in environmental risk assessment and in particular the protection of species that provide ecosystem services, yet there are no standard protocols in place for the choice of surrogates. Surrogates are often chosen on the basis of convenience or ...

Bioorthogonal Noncanonical Amino Acid Tagging (BONCAT) Enables Time-Resolved Analysis of Protein Synthesis in Native Plant Tissue1[OPEN

PubMed Central

Moradian, Annie

2017-01-01

Proteomic plasticity undergirds stress responses in plants, and understanding such responses requires accurate measurement of the extent to which proteins levels are adjusted to counter external stimuli. Here, we adapt bioorthogonal noncanonical amino acid tagging (BONCAT) to interrogate protein synthesis in vegetative Arabidopsis (Arabidopsis thaliana) seedlings. BONCAT relies on the translational incorporation of a noncanonical amino acid probe into cellular proteins. In this study, the probe is the Met surrogate azidohomoalanine (Aha), which carries a reactive azide moiety in its amino acid side chain. The azide handle in Aha can be selectively conjugated to dyes and functionalized beads to enable visualization and enrichment of newly synthesized proteins. We show that BONCAT is sensitive enough to detect Arabidopsis proteins synthesized within a 30-min interval defined by an Aha pulse and that the method can be used to detect proteins made under conditions of light stress, osmotic shock, salt stress, heat stress, and recovery from heat stress. We further establish that BONCAT can be coupled to tandem liquid chromatography-mass spectrometry to identify and quantify proteins synthesized during heat stress and recovery from heat stress. Our results are consistent with a model in which, upon the onset of heat stress, translation is rapidly reprogrammed to enhance the synthesis of stress mitigators and is again altered during recovery. All experiments were carried out with commercially available reagents, highlighting the accessibility of the BONCAT method to researchers interested in stress responses as well as translational and posttranslational regulation in plants. PMID:28104718

Charge-transfer dynamics in one-dimensional C 60 chains

NASA Astrophysics Data System (ADS)

Pérez-Dieste, V.; Tamai, A.; Greber, T.; Chiuzbaˇian, S. G.; Patthey, L.

2008-06-01

Charge transfer in highly-ordered C 60 chains grown on a Cu(5 5 3) vicinal surface is studied by means of resonant photoemission. Tuning the light polarization, autoionization of the highest occupied molecular orbital (HOMO) was expected to detect anisotropy in this one-dimensional system. For one monolayer C 60 we found no signature of autoionization. This indicates that for an electron which is excited from the C 1s level of C 60 to the lowest unoccupied molecular orbital (LUMO), hybridization leads to delocalization on the femtosecond time-scale and no influence of the light polarization is observed.

Outcomes for Gestational Carriers Versus Traditional Surrogates in the United States.

PubMed

Fuchs, Erika L; Berenson, Abbey B

2018-05-01

Little is known about the obstetric and procedural outcomes of traditional surrogates and gestational carriers. Participants included 222 women living in the United States who completed a brief online survey between November 2015 and February 2016. Differences between gestational carriers (n = 204) and traditional surrogates (n = 18) in demographic characteristics, pregnancy outcomes, and procedural outcomes were examined using chi-squared tests, Fisher's exact tests, and t-tests. Out of 248 eligible respondents, 222 surveys were complete, for a response rate of 89.5%. Overall, obstetric outcomes were similar among gestational carriers and traditional surrogates. Traditional surrogates were more likely than gestational carriers to have a Center for Epidemiologic Studies Depression Scale Revised score of 16 or higher (37.5% vs. 4.0%). Gestational carriers reported higher mean compensation ($27,162.80 vs. $17,070.07) and were more likely to travel over 400 miles (46.0% vs. 0.0%) than traditional surrogates. Procedural differences, but not differences in obstetric outcomes, emerged between gestational carriers and traditional surrogates. To ensure that both traditional surrogates and gestational carriers receive optimal medical care, it may be necessary to extend practice guidelines to ensure that traditional surrogates are offered the same level of care offered to gestational carriers.

Dynamic response due to behind helmet blunt trauma measured with a human head surrogate.

PubMed

Freitas, Christopher J; Mathis, James T; Scott, Nikki; Bigger, Rory P; Mackiewicz, James

2014-01-01

A Human Head Surrogate has been developed for use in behind helmet blunt trauma experiments. This human head surrogate fills the void between Post-Mortem Human Subject testing (with biofidelity but handling restrictions) and commercial ballistic head forms (with no biofidelity but ease of use). This unique human head surrogate is based on refreshed human craniums and surrogate materials representing human head soft tissues such as the skin, dura, and brain. A methodology for refreshing the craniums is developed and verified through material testing. A test methodology utilizing these unique human head surrogates is also developed and then demonstrated in a series of experiments in which non-perforating ballistic impact of combat helmets is performed with and without supplemental ceramic appliques for protecting against larger caliber threats. Sensors embedded in the human head surrogates allow for direct measurement of intracranial pressure, cranial strain, and head and helmet acceleration. Over seventy (70) fully instrumented experiments have been executed using this unique surrogate. Examples of the data collected are presented. Based on these series of tests, the Southwest Research Institute (SwRI) Human Head Surrogate has demonstrated great potential for providing insights in to injury mechanics resulting from non-perforating ballistic impact on combat helmets, and directly supports behind helmet blunt trauma studies.

Surrogate markers for time-varying treatments and outcomes

PubMed Central

Hsu, Jesse Y; Kennedy, Edward H; Roy, Jason A; Stephens-Shields, Alisa J; Small, Dylan S; Joffe, Marshall M

2015-01-01

Background A surrogate marker is a variable commonly used in clinical trials to guide treatment decisions when the outcome of ultimate interest is not available. A good surrogate marker is one where the treatment effect on the surrogate is a strong predictor of the effect of treatment on the outcome. We review the situation when there is one treatment delivered at baseline, one surrogate measured at one later time point and one ultimate outcome of interest, and discuss new issues arising when variables are time-varying. Methods Most of the literature on surrogate markers has only considered simple settings with one treatment, one surrogate, and one outcome of interest at a fixed time point. However, more complicated time-varying settings are common in practice. In this paper, we describe the unique challenges in two settings, time-varying treatments and time-varying surrogates, while relating the ideas back to the causal-effects and causal-association paradigms. Conclusions In addition to discussing and extending popular notions of surrogacy to time-varying settings, we give examples illustrating that one can be misled by not taking into account time-varying information about the surrogate or treatment. We hope this paper has provided some motivation for future work on estimation and inference in such settings. PMID:25948621

Interpretations, perspectives and intentions in surrogate motherhood

PubMed Central

van Zyl, L.; van Niekerk, A.

2000-01-01

In this paper we examine the questions "What does it mean to be a surrogate mother?" and "What would be an appropriate perspective for a surrogate mother to have on her pregnancy?" In response to the objection that such contracts are alienating or dehumanising since they require women to suppress their evolving perspective on their pregnancies, liberal supporters of surrogate motherhood argue that the freedom to contract includes the freedom to enter a contract to bear a child for an infertile couple. After entering the contract the surrogate may not be free to interpret her pregnancy as that of a non-surrogate mother, but there is more than one appropriate way of interpreting one's pregnancy. To restrict or ban surrogacy contracts would be to prohibit women from making other particular interpretations of their pregnancies they may wish to make, requiring them to live up to a culturally constituted image of ideal motherhood. We examine three interpretations of a "surrogate pregnancy" that are implicit in the views and arguments put forward by ethicists, surrogacy agencies, and surrogate mothers themselves. We hope to show that our concern in this regard goes beyond the view that surrogacy contracts deny or suppress the natural, instinctive or conventional interpretation of pregnancy. Key Words: Surrogate motherhood • parental rights and responsibilities PMID:11055048

Dynamic Response Due to Behind Helmet Blunt Trauma Measured with a Human Head Surrogate

PubMed Central

Freitas, Christopher J.; Mathis, James T.; Scott, Nikki; Bigger, Rory P.; MacKiewicz, James

2014-01-01

A Human Head Surrogate has been developed for use in behind helmet blunt trauma experiments. This human head surrogate fills the void between Post-Mortem Human Subject testing (with biofidelity but handling restrictions) and commercial ballistic head forms (with no biofidelity but ease of use). This unique human head surrogate is based on refreshed human craniums and surrogate materials representing human head soft tissues such as the skin, dura, and brain. A methodology for refreshing the craniums is developed and verified through material testing. A test methodology utilizing these unique human head surrogates is also developed and then demonstrated in a series of experiments in which non-perforating ballistic impact of combat helmets is performed with and without supplemental ceramic appliques for protecting against larger caliber threats. Sensors embedded in the human head surrogates allow for direct measurement of intracranial pressure, cranial strain, and head and helmet acceleration. Over seventy (70) fully instrumented experiments have been executed using this unique surrogate. Examples of the data collected are presented. Based on these series of tests, the Southwest Research Institute (SwRI) Human Head Surrogate has demonstrated great potential for providing insights in to injury mechanics resulting from non-perforating ballistic impact on combat helmets, and directly supports behind helmet blunt trauma studies. PMID:24688303

Selection of Surrogate Bacteria for Use in Food Safety Challenge Studies: A Review.

PubMed

Hu, Mengyi; Gurtler, Joshua B

2017-09-01

Nonpathogenic surrogate bacteria are prevalently used in a variety of food challenge studies in place of foodborne pathogens such as Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Clostridium botulinum because of safety and sanitary concerns. Surrogate bacteria should have growth characteristics and/or inactivation kinetics similar to those of target pathogens under given conditions in challenge studies. It is of great importance to carefully select and validate potential surrogate bacteria when verifying microbial inactivation processes. A validated surrogate responds similar to the targeted pathogen when tested for inactivation kinetics, growth parameters, or survivability under given conditions in agreement with appropriate statistical analyses. However, a considerable number of food studies involving putative surrogate bacteria lack convincing validation sources or adequate validation processes. Most of the validation information for surrogates in these studies is anecdotal and has been collected from previous publications but may not be sufficient for given conditions in the study at hand. This review is limited to an overview of select studies and discussion of the general criteria and approaches for selecting potential surrogate bacteria under given conditions. The review also includes a list of documented bacterial pathogen surrogates and their corresponding food products and treatments to provide guidance for future studies.

Health information-seeking on behalf of others: characteristics of "surrogate seekers".

PubMed

Cutrona, Sarah L; Mazor, Kathleen M; Vieux, Sana N; Luger, Tana M; Volkman, Julie E; Finney Rutten, Lila J

2015-03-01

Understanding the behaviors of surrogate seekers (those who seek health information for others) may guide efforts to improve health information transmission. We used 2011-2012 data from the Health Information National Trends Survey to describe behaviors of online surrogate seekers. Respondents were asked about use of the Internet for surrogate-seeking over the prior 12 months. Data were weighted to calculate population estimates. Two thirds (66.6%) reported surrogate-seeking. Compared to those who sought health information online for only themselves, surrogate seekers were more likely to live in households with others (weighted percent 89.4 vs. 82.5% of self-seekers; p < 0.05); no significant differences in sex, race, income or education were observed. Surrogate seekers were more likely to report activities requiring user-generated content: email communication with healthcare providers; visits to social networking sites to read and share about medical topics and participation in online health support groups. On multivariate analysis, those who had looked online for healthcare providers were more likely to be surrogate seekers (OR 1.67, 95% CI 1.08-2.59). In addition to seeking health information, surrogate seekers create and pass along communications that may influence medical care decisions. Research is needed to identify ways to facilitate transmission of accurate health information.

Health information seeking on behalf of others: Characteristics of ‘surrogate seekers’

PubMed Central

Cutrona, Sarah L.; Mazor, Kathleen M.; Vieux, Sana N.; Luger, Tana M.; Volkman, Julie E.; Finney Rutten, Lila J.

2014-01-01

Understanding the behaviors of surrogate-seekers (those who seek health information for others) may guide efforts to improve health information transmission. We used 2011–2012 data from the Health Information National Trends Survey to describe behaviors of online surrogate-seekers. Respondents were asked about use of the Internet for surrogate-seeking over the prior 12 months. Data were weighted to calculate population estimates. Two-thirds (66.6%) reported surrogate-seeking. Compared to those who sought health information online for only themselves, surrogate-seekers were more likely to live in households with others (weighted percent 89.4% vs. 82.5% of self-seekers; p < 0.05); no significant differences in sex, race, income or education were observed. Surrogate-seekers were more likely to report activities requiring user-generated content: email communication with healthcare providers; visits to social networking sites to read and share about medical topics and participation in online health support groups. On multivariate analysis, those who had looked online for healthcare providers were more likely to be surrogate-seekers (OR 1.67, 95% CI 1.08–2.59). In addition to seeking health information, surrogate-seekers create and pass along communications that may influence medical care decisions. Research is needed to identify ways to facilitate transmission of accurate health information. PMID:24989816

Cavity-Enhanced Raman Spectroscopy for Food Chain Management

PubMed Central

Sandfort, Vincenz; Goldschmidt, Jens; Wöllenstein, Jürgen

2018-01-01

Comprehensive food chain management requires the monitoring of many parameters including temperature, humidity, and multiple gases. The latter is highly challenging because no low-cost technology for the simultaneous chemical analysis of multiple gaseous components currently exists. This contribution proposes the use of cavity enhanced Raman spectroscopy to enable online monitoring of all relevant components using a single laser source. A laboratory scale setup is presented and characterized in detail. Power enhancement of the pump light is achieved in an optical resonator with a Finesse exceeding 2500. A simulation for the light scattering behavior shows the influence of polarization on the spatial distribution of the Raman scattered light. The setup is also used to measure three relevant showcase gases to demonstrate the feasibility of the approach, including carbon dioxide, oxygen and ethene. PMID:29495501

Surrogate outcomes are associated with low methodological quality of studies of rheumatoid arthritis treated with antitumour necrosis factor agents: a systematic review.

PubMed

Nobre, Moacyr Roberto Cuce; da Costa, Frnanda Marques

2012-02-01

Surrogate endpoints may be used as substitutes for, but often do not predict clinically relevant events. Objective To assess the methodological quality of articles that present their conclusions based on clinically relevant or surrogate outcomes in a systematic review of randomised trials and cohort studies of patients with rheumatoid arthritis treated with antitumour necrosis factor (TNF) agents. PubMed, Embase and Cochrane databases were searched. The Jadad score, the percentage of Consolidated Standards Of Reporting Trials (CONSORT) statement items adequately reported and levels-of-evidence (Center for Evidence-based Medicine, Oxford) were used in a descriptive synthesis. Among 88 articles appraised, 27 had surrogate endpoints, mainly radiographic, and 44 were duplicate publications; 74% of articles with surrogate and 39% of articles with clinical endpoints (p=0.006). Fewer articles with surrogate endpoints represented a high level of evidence (Level 1b, 33% vs 62%, p=0.037) and the mean percentage of CONSORT statement items met was also lower for articles with surrogate endpoints (62.5 vs 70.7, p=0.026). Although fewer articles with surrogate endpoints were randomised trials (63% vs 74%, p=0.307) and articles with surrogate endpoints had lower Jadad scores (3.0 vs 3.2, p=0.538), these differences were not statistically significant. Studies of anti-TNF agents that report surrogate outcomes are of lesser methodological quality. As such, inclusion of such studies in evidence syntheses may bias results.

The Different Moral Bases of Patient and Surrogate Decision-Making.

PubMed

Brudney, Daniel

2018-01-01

My topic is a problem with our practice of surrogate decision-making in health care, namely, the problem of the surrogate who is not doing her job-the surrogate who cannot be reached or the surrogate who seems to refuse to understand or to be unable to understand the clinical situation. The analysis raises a question about the surrogate who simply disagrees with the medical team. One might think that such a surrogate is doing her job-the team just doesn't like how she is doing it. My analysis raises the question of whether (or perhaps when) she should be overridden. In approaching this problem, I focus not on the range of difficulties in practice but on the underlying moral conceptual issue. My concern will be to show that the moral values that underpin patient decision-making are fundamentally different from those that underpin surrogate decision-making. Identifying the distinctions will set parameters for any successful solution to the "Who should decide?" A patient has a specific kind of moral right to make her own medical decisions. A surrogate has no analogous moral right to decide for someone else. We want the surrogate to make the decision because we believe that she has a relevant epistemological advantage over anyone else on the scene. If and when she has no such advantage or if she refuses or is unable to use it, then there might not be sufficient reason to let her be the decision-maker. © 2018 The Hastings Center.

The Use of Surrogate Endpoints in Regulating Medicines for Cardio-Renal Disease: Opinions of Stakeholders

PubMed Central

Schievink, Bauke; Lambers Heerspink, Hiddo; Leufkens, Hubert; De Zeeuw, Dick; Hoekman, Jarno

2014-01-01

Aim There is discussion whether medicines can be authorized on the market based on evidence from surrogate endpoints. We assessed opinions of different stakeholders on this topic. Methods We conducted an online questionnaire that targeted various stakeholder groups (regulatory agencies, pharmaceutical industry, academia, relevant public sector organisations) and medical specialties (cardiology or nephrology vs. other). Participants were enrolled through purposeful sampling. We inquired for conditions under which surrogate endpoints can be used, the validity of various cardio-renal biomarkers and new approaches for biomarker use. Results Participants agreed that surrogate endpoints can be used when the surrogate is scientifically valid (5-point Likert response format, mean score: 4.3, SD: 0.9) or when there is an unmet clinical need (mean score: 3.8, SD: 1.2). Industry participants agreed to a greater extent than regulators and academics. However, out of four proposed surrogates (blood pressure (BP), HbA1c, albuminuria, CRP) for cardiovascular outcomes or end-stage renal disease, only use of BP for cardiovascular outcomes was deemed moderately accurate (mean: 3.6, SD: 1.1). Specialists in cardiology or nephrology tended to be more positive about the use of surrogate endpoints. Conclusion Stakeholders in drug development do not oppose to the use of surrogate endpoints in drug marketing authorization, but most surrogates are not considered valid. To solve this impasse, increased efforts are required to validate surrogate endpoints and to explore alternative ways to use them. PMID:25268242

The use of surrogate endpoints in regulating medicines for cardio-renal disease: opinions of stakeholders.

PubMed

Schievink, Bauke; Lambers Heerspink, Hiddo; Leufkens, Hubert; De Zeeuw, Dick; Hoekman, Jarno

2014-01-01

There is discussion whether medicines can be authorized on the market based on evidence from surrogate endpoints. We assessed opinions of different stakeholders on this topic. We conducted an online questionnaire that targeted various stakeholder groups (regulatory agencies, pharmaceutical industry, academia, relevant public sector organisations) and medical specialties (cardiology or nephrology vs. other). Participants were enrolled through purposeful sampling. We inquired for conditions under which surrogate endpoints can be used, the validity of various cardio-renal biomarkers and new approaches for biomarker use. Participants agreed that surrogate endpoints can be used when the surrogate is scientifically valid (5-point Likert response format, mean score: 4.3, SD: 0.9) or when there is an unmet clinical need (mean score: 3.8, SD: 1.2). Industry participants agreed to a greater extent than regulators and academics. However, out of four proposed surrogates (blood pressure (BP), HbA1c, albuminuria, CRP) for cardiovascular outcomes or end-stage renal disease, only use of BP for cardiovascular outcomes was deemed moderately accurate (mean: 3.6, SD: 1.1). Specialists in cardiology or nephrology tended to be more positive about the use of surrogate endpoints. Stakeholders in drug development do not oppose to the use of surrogate endpoints in drug marketing authorization, but most surrogates are not considered valid. To solve this impasse, increased efforts are required to validate surrogate endpoints and to explore alternative ways to use them.

Communicating with Clinicians: The Experiences of Surrogate Decision Makers for Hospitalized Older Adults

PubMed Central

Torke, Alexia M.; Petronio, Sandra; Purnell, Christianna E.; Sachs, Greg A.; Helft, Paul R.; Callahan, Christopher M.

2012-01-01

Background/Objectives When hospitalized older adults have impaired cognition, family members or other surrogates must communicate with clinicians to provide information and make medical decisions for the patient. The present study describes communication experiences of surrogates who recently made a major medical decision for a hospitalized older adult. Design Semi-structured interviews about a recent hospitalization. Setting Two hospitals both affiliated with 1 large medical school: an urban, public hospital; and a university-affiliated tertiary referral hospital. Participants Surrogates were eligible if they had recently made a major medical decision for a hospitalized patient aged 65 or older and were available for an interview within 1 month (2-5 months if the patient died). Measurements Interviews were audio-recorded, transcribed, and analyzed using methods of grounded theory. Results We interviewed 35 surrogates. They were 80% female, 44% white and 56% African American. Three primary themes emerged. We found the Nature of Surrogate/Clinician Relationships was best characterized as a relationship with a “team” of clinicians rather than individual clinicians due to frequent staff changes and multiple clinicians. Surrogates reported their Communication Needs, including frequent communication, information, and emotional support. Surrogates valued communication from any member of the clinical team, including nurses, social workers, and physicians. Third, surrogates described Trust and Mistrust, which were formed largely through surrogates’ communication experiences. Conclusion In the hospital, surrogates form relationships with a “team” of clinicians rather than with individuals. Yet effective communication and expressions of emotional support frequently occur and are highly valued by surrogates. Future interventions should focus on meeting surrogates’ needs for frequent communication, high levels of information and emotional support. PMID:22881864

Critical care physicians’ approaches to negotiating with surrogate decision makers: a qualitative study

PubMed Central

Brush, David R.; Brown, Crystal E.; Alexander, G. Caleb

2013-01-01

Objective To describe how critical care physicians manage conflicts with surrogates about withdrawing or withholding patients’ life support. Design Qualitative analysis of key informant interviews with critical care physicians during 2010. We transcribed interviews verbatim and used grounded theory to code and revise a taxonomy of themes and to identify illustrative quotes. Setting 3 academic medical centers, 1 academic-affiliated medical center and 4 private practice groups or private hospitals in a large Midwestern city Subjects 14 critical care physicians Measurements and main results Physicians reported tailoring their approach to address specific reasons for disagreement with surrogates. Five common approaches were identified: (1) building trust, (2) educating and informing, (3) providing surrogates more time, (4) adjusting surrogate and physician roles, and (5) highlighting specific values. When mistrust was an issue, physicians endeavored to build a more trusting relationship with the surrogate before re-addressing decision making. Physicians also reported correcting misunderstandings by providing targeted education, and some reported highlighting specific patient, surrogate, or physician values that they hoped would guide surrogates to agree with them. When surrogates struggled with decision making roles, physicians attempted to reinforce the concept of substituted judgment. Physicians noted that some surrogates needed time to “come to terms” with the patent’s illness before agreeing with physicians. Many physicians had witnessed colleagues negotiate in ways they found objectionable, such as providing misleading information, injecting their own values into the negotiation, or behaving unprofessionally towards surrogates. While some physicians viewed their efforts to encourage surrogates’ agreement as persuasive, others strongly denied persuading surrogates and described their actions as “guiding” or “negotiating.” Conclusions Physicians reported using a tailored approach to resolve decisional conflicts about life support; and attempted to change surrogates’ decisions in accordance with what the physician thought was in the patients’ best interests. While physicians acknowledged their efforts to change surrogate’s decisions, many physicians did not perceive these as persuasive. PMID:22080645

Use of surrogate outcomes in US FDA drug approvals, 2003-2012: a survey.

PubMed

Yu, Tsung; Hsu, Yea-Jen; Fain, Kevin M; Boyd, Cynthia M; Holbrook, Janet T; Puhan, Milo A

2015-11-27

To evaluate, across a spectrum of diseases, how often surrogate outcomes are used as a basis for drug approvals by the US Food and Drug Administration (FDA), and whether and how the rationale for using treatment effects on surrogates as predictors of treatment effects on patient-centred outcomes is discussed. We used the Drugs@FDA website to identify drug approvals produced from 2003 to 2012 by the FDA. We focused on four diseases (chronic obstructive pulmonary disease (COPD), type 1 or 2 diabetes, glaucoma and osteoporosis) for which surrogates are commonly used in trials. We reviewed the drug labels and medical reviews to provide empirical evidence on how surrogate outcomes are handled by the FDA. Of 1043 approvals screened, 58 (6%) were for the four diseases of interest. Most drugs for COPD (7/9, 78%), diabetes (26/26, 100%) and glaucoma (9/9, 100%) were approved based on surrogates while for osteoporosis, most drugs (10/14, 71%) were also approved for patient-centred outcomes (fractures). The rationale for using surrogates was discussed in 11 of the 43 (26%) drug approvals based on surrogates. In these drug approvals, we found drug approvals for diabetes are more likely than the other examined conditions to contain a discussion of trial evidence demonstrating that treatment effects on surrogate outcomes predict treatment effects on patient-centred outcomes. Our results suggest that the FDA did not use a consistent approach to address surrogates in assessing the benefits and harms of drugs for COPD, type 1 or 2 diabetes, glaucoma and osteoporosis. For evaluating new drugs, patient-centred outcomes should be chosen whenever possible. If the use of surrogate outcomes is necessary, then a consistent approach is important to review the evidence for surrogacy and consider surrogate's usage in the treatment and population under study. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Doubt and belief in physicians' ability to prognosticate during critical illness: The perspective of surrogate decision makers

PubMed Central

Zier, Lucas S.; Burack, Jeffrey H.; Micco, Guy; Chipman, Anne K.; Frank, James A.; Luce, John M.; White, Douglas B.

2009-01-01

Objectives: Although discussing a prognosis is a duty of physicians caring for critically ill patients, little is known about surrogate decision-makers' beliefs about physicians' ability to prognosticate. We sought to determine: 1) surrogates' beliefs about whether physicians can accurately prognosticate for critically ill patients; and 2) how individuals use prognostic information in their role as surrogate decision-makers. Design, Setting, and Patients: Multicenter study in intensive care units of a public hospital, a tertiary care hospital, and a veterans' hospital. We conducted semistructured interviews with 50 surrogate decision-makers of critically ill patients. We analyzed the interview transcripts using grounded theory methods to inductively develop a framework to describe surrogates' beliefs about physicians' ability to prognosticate. Validation methods included triangulation by multidisciplinary analysis and member checking. Measurements and Main Results: Overall, 88% (44 of 50) of surrogates expressed doubt about physicians' ability to prognosticate for critically ill patients. Four distinct themes emerged that explained surrogates' doubts about prognostic accuracy: a belief that God could alter the course of the illness, a belief that predicting the future is inherently uncertain, prior experiences where physicians' prognostications were inaccurate, and experiences with prognostication during the patient's intensive care unit stay. Participants also identified several factors that led to belief in physicians' prognostications, such as receiving similar prognostic estimates from multiple physicians and prior experiences with accurate prognostication. Surrogates' doubts about prognostic accuracy did not prevent them from wanting prognostic information. Instead, most surrogate decision-makers view physicians' prognostications as rough estimates that are valuable in informing decisions, but are not determinative. Surrogates identified the act of prognostic disclosure as a key step in preparing emotionally and practically for the possibility that a patient may not survive. Conclusions: Although many surrogate decision-makers harbor some doubt about the accuracy of physicians' prognostications, they highly value discussions about prognosis and use the information for multiple purposes. (Crit Care Med 2008; 36: 2341–2347) PMID:18596630

Comparison between surrogate indexes of insulin sensitivity/resistance and hyperinsulinemic euglycemic clamp estimates in rats

PubMed Central

Muniyappa, Ranganath; Chen, Hui; Muzumdar, Radhika H.; Einstein, Francine H.; Yan, Xu; Yue, Lilly Q.; Barzilai, Nir

2009-01-01

Assessing insulin resistance in rodent models gives insight into mechanisms that cause type 2 diabetes and the metabolic syndrome. The hyperinsulinemic euglycemic glucose clamp, the reference standard for measuring insulin sensitivity in humans and animals, is labor intensive and technically demanding. A number of simple surrogate indexes of insulin sensitivity/resistance have been developed and validated primarily for use in large human studies. These same surrogates are also frequently used in rodent studies. However, in general, these indexes have not been rigorously evaluated in animals. In a recent validation study in mice, we demonstrated that surrogates have a weaker correlation with glucose clamp estimates of insulin sensitivity/resistance than in humans. This may be due to increased technical difficulties in mice and/or intrinsic differences between human and rodent physiology. To help distinguish among these possibilities, in the present study, using data from rats substantially larger than mice, we compared the clamp glucose infusion rate (GIR) with surrogate indexes, including QUICKI, HOMA, 1/HOMA, log (HOMA), and 1/fasting insulin. All surrogates were modestly correlated with GIR (r = 0.34–0.40). Calibration analyses of surrogates adjusted for body weight demonstrated similar predictive accuracy for GIR among all surrogates. We conclude that linear correlations of surrogate indexes with clamp estimates and predictive accuracy of surrogate indexes in rats are similar to those in mice (but not as substantial as in humans). This additional rat study (taken with the previous mouse study) suggests that application of surrogate insulin sensitivity indexes developed for humans may not be appropriate for determining primary outcomes in rodent studies due to intrinsic differences in metabolic physiology. However, use of surrogates may be appropriate in rodents, where feasibility of clamps is an obstacle and measurement of insulin sensitivity is a secondary outcome. PMID:19706785

Surface contamination of hazardous drug pharmacy storage bins and pharmacy distributor shipping containers.

PubMed

Redic, Kimberly A; Fang, Kayleen; Christen, Catherine; Chaffee, Bruce W

2018-03-01

Purpose This study was conducted to determine whether there is contamination on exterior drug packaging using shipping totes from the distributor and carousel storage bins as surrogate markers of external packaging contamination. Methods A two-part study was conducted to measure the presence of 5-fluorouracil, ifosfamide, cyclophosphamide, docetaxel and paclitaxel using surrogate markers for external drug packaging. In Part I, 10 drug distributor shipping totes designated for transport of hazardous drugs provided a snapshot view of contamination from regular use and transit in and out of the pharmacy. An additional two totes designated for transport of non-hazardous drugs served as controls. In Part II, old carousel storage bins (i.e. those in use pre-study) were wiped for snapshot view of hazardous drug contamination on storage bins. New carousel storage bins were then put into use for storage of the five tested drugs and used for routine storage and inventory maintenance activities. Carousel bins were wiped at time intervals 0, 8, 16 and 52 weeks to measure surface contamination. Results Two of the 10 hazardous shipping totes were contaminated. Three of the five-old carousel bins were contaminated with cyclophosphamide. One of the old carousel bins was also contaminated with ifosfamide. There were no detectable levels of hazardous drugs on any of the new storage bins at time 0, 8 or 16 weeks. However, at the Week 52, there was a detectable level of 5-FU present in the 5-FU carousel bin. Conclusions Contamination of the surrogate markers suggests that external packaging for hazardous drugs is contaminated, either during the manufacturing process or during routine chain of custody activities. These results demonstrate that occupational exposure may occur due to contamination from shipping totes and storage bins, and that handling practices including use of personal protective equipment is warranted.

Airway structural alterations selectively associated with severe asthma.

PubMed

Benayoun, Laurent; Druilhe, Anne; Dombret, Marie-Christine; Aubier, Michel; Pretolani, Marina

2003-05-15

To identify airway pathologic abnormalities selectively associated with severe asthma, we examined 10 control subjects, 10 patients with intermittent asthma, 15 patients with mild-to-moderate persistent asthma, 15 patients with severe persistent asthma, and 10 patients with chronic obstructive pulmonary disease. Bronchial biopsies were assessed for epithelial integrity; subepithelial basement membrane (SBM) thickness; collagen type III deposition; eosinophil, neutrophil, and fibroblast numbers; mucous gland and airway smooth muscle (ASM) areas; SBM-ASM distance; ASM hypertrophy (increased cell size); and the expression of the contractile proteins alpha-actin, smooth muscle myosin heavy-chain isoforms, myosin light-chain kinase, and the phosphorylated form of the regulatory light chain of myosin. Neither mucosal eosinophilia nor neutrophilia, epithelial damage, or SBM thickness reflected asthma severity. In contrast, higher numbers of fibroblasts (p < 0.001), an increase in collagen type III deposition (p < 0.020), larger mucous gland (p < 0.040) and ASM (p < 0.001) areas, augmented ASM cell size (p < 0.001), and myosin light-chain kinase expression (p < 0.005) distinguished patients with severe persistent asthma from patients with milder disease or with chronic obstructive pulmonary disease. Stepwise multivariate regression analysis established that fibroblast numbers and ASM cell size were negatively associated with prebronchodilator and postbronchodilator FEV1 values in patients with asthma. We conclude that fibroblast accumulation and ASM hypertrophy in proximal airways are selective determinants of severe persistent asthma.

Ectromelia Virus Disease Characterization in the BALB/c Mouse: A Surrogate Model for Assessment of Smallpox Medical Countermeasures

PubMed Central

Garver, Jennifer; Weber, Lauren; Vela, Eric M.; Anderson, Mike; Warren, Richard; Merchlinsky, Michael; Houchens, Christopher; Rogers, James V.

2016-01-01

In 2007, the United States– Food and Drug Administration (FDA) issued guidance concerning animal models for testing the efficacy of medical countermeasures against variola virus (VARV), the etiologic agent for smallpox. Ectromelia virus (ECTV) is naturally-occurring and responsible for severe mortality and morbidity as a result of mousepox disease in the murine model, displaying similarities to variola infection in humans. Due to the increased need of acceptable surrogate animal models for poxvirus disease, we have characterized ECTV infection in the BALB/c mouse. Mice were inoculated intranasally with a high lethal dose (125 PFU) of ECTV, resulting in complete mortality 10 days after infection. Decreases in weight and temperature from baseline were observed eight to nine days following infection. Viral titers via quantitative polymerase chain reaction (qPCR) and plaque assay were first observed in the blood at 4.5 days post-infection and in tissue (spleen and liver) at 3.5 days post-infection. Adverse clinical signs of disease were first observed four and five days post-infection, with severe signs occurring on day 7. Pathological changes consistent with ECTV infection were first observed five days after infection. Examination of data obtained from these parameters suggests the ECTV BALB/c model is suitable for potential use in medical countermeasures (MCMs) development and efficacy testing. PMID:27455306

Ectromelia Virus Disease Characterization in the BALB/c Mouse: A Surrogate Model for Assessment of Smallpox Medical Countermeasures.

PubMed

Garver, Jennifer; Weber, Lauren; Vela, Eric M; Anderson, Mike; Warren, Richard; Merchlinsky, Michael; Houchens, Christopher; Rogers, James V

2016-07-22

In 2007, the United States- Food and Drug Administration (FDA) issued guidance concerning animal models for testing the efficacy of medical countermeasures against variola virus (VARV), the etiologic agent for smallpox. Ectromelia virus (ECTV) is naturally-occurring and responsible for severe mortality and morbidity as a result of mousepox disease in the murine model, displaying similarities to variola infection in humans. Due to the increased need of acceptable surrogate animal models for poxvirus disease, we have characterized ECTV infection in the BALB/c mouse. Mice were inoculated intranasally with a high lethal dose (125 PFU) of ECTV, resulting in complete mortality 10 days after infection. Decreases in weight and temperature from baseline were observed eight to nine days following infection. Viral titers via quantitative polymerase chain reaction (qPCR) and plaque assay were first observed in the blood at 4.5 days post-infection and in tissue (spleen and liver) at 3.5 days post-infection. Adverse clinical signs of disease were first observed four and five days post-infection, with severe signs occurring on day 7. Pathological changes consistent with ECTV infection were first observed five days after infection. Examination of data obtained from these parameters suggests the ECTV BALB/c model is suitable for potential use in medical countermeasures (MCMs) development and efficacy testing.

Probabilistic Prognosis of Non-Planar Fatigue Crack Growth

NASA Technical Reports Server (NTRS)

Leser, Patrick E.; Newman, John A.; Warner, James E.; Leser, William P.; Hochhalter, Jacob D.; Yuan, Fuh-Gwo

2016-01-01

Quantifying the uncertainty in model parameters for the purpose of damage prognosis can be accomplished utilizing Bayesian inference and damage diagnosis data from sources such as non-destructive evaluation or structural health monitoring. The number of samples required to solve the Bayesian inverse problem through common sampling techniques (e.g., Markov chain Monte Carlo) renders high-fidelity finite element-based damage growth models unusable due to prohibitive computation times. However, these types of models are often the only option when attempting to model complex damage growth in real-world structures. Here, a recently developed high-fidelity crack growth model is used which, when compared to finite element-based modeling, has demonstrated reductions in computation times of three orders of magnitude through the use of surrogate models and machine learning. The model is flexible in that only the expensive computation of the crack driving forces is replaced by the surrogate models, leaving the remaining parameters accessible for uncertainty quantification. A probabilistic prognosis framework incorporating this model is developed and demonstrated for non-planar crack growth in a modified, edge-notched, aluminum tensile specimen. Predictions of remaining useful life are made over time for five updates of the damage diagnosis data, and prognostic metrics are utilized to evaluate the performance of the prognostic framework. Challenges specific to the probabilistic prognosis of non-planar fatigue crack growth are highlighted and discussed in the context of the experimental results.

A surrogate-based sensitivity quantification and Bayesian inversion of a regional groundwater flow model

NASA Astrophysics Data System (ADS)

Chen, Mingjie; Izady, Azizallah; Abdalla, Osman A.; Amerjeed, Mansoor

2018-02-01

Bayesian inference using Markov Chain Monte Carlo (MCMC) provides an explicit framework for stochastic calibration of hydrogeologic models accounting for uncertainties; however, the MCMC sampling entails a large number of model calls, and could easily become computationally unwieldy if the high-fidelity hydrogeologic model simulation is time consuming. This study proposes a surrogate-based Bayesian framework to address this notorious issue, and illustrates the methodology by inverse modeling a regional MODFLOW model. The high-fidelity groundwater model is approximated by a fast statistical model using Bagging Multivariate Adaptive Regression Spline (BMARS) algorithm, and hence the MCMC sampling can be efficiently performed. In this study, the MODFLOW model is developed to simulate the groundwater flow in an arid region of Oman consisting of mountain-coast aquifers, and used to run representative simulations to generate training dataset for BMARS model construction. A BMARS-based Sobol' method is also employed to efficiently calculate input parameter sensitivities, which are used to evaluate and rank their importance for the groundwater flow model system. According to sensitivity analysis, insensitive parameters are screened out of Bayesian inversion of the MODFLOW model, further saving computing efforts. The posterior probability distribution of input parameters is efficiently inferred from the prescribed prior distribution using observed head data, demonstrating that the presented BMARS-based Bayesian framework is an efficient tool to reduce parameter uncertainties of a groundwater system.

¹⁵N, ¹³C and ¹H resonance assignments and secondary structure determination of a variable heavy domain of a heavy chain antibody.

PubMed

Prosser, Christine E; Waters, Lorna C; Muskett, Frederick W; Veverka, Vaclav; Addis, Philip W; Griffin, Laura M; Baker, Terry S; Lawson, Alastair D G; Wernery, Ulrich; Kinne, Jorg; Henry, Alistair J; Taylor, Richard J; Carr, Mark D

2014-04-01

Heavy chain antibodies differ in structure to conventional antibodies lacking both the light chain and the first heavy chain constant domain (CH1). Characteristics of the antigen-binding variable heavy domain of the heavy chain antibody (VHH) including the smaller size, high solubility and stability make them an attractive alternative to more traditional antibody fragments for detailed NMR-based structural analysis. Here we report essentially complete backbone and side chain (15)N, (13)C and (1)H assignments for a free VHH. Analysis of the backbone chemical shift data obtained indicates that the VHH is comprised predominantly of β-sheets corresponding to nearly 60% of the protein backbone.

75 FR 3446 - Certain Frozen Warmwater Shrimp From the Socialist Republic of Vietnam: Preliminary Intent To...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-21

... Notice of Amended Final Determination of Sales at Less Than Fair Value and Antidumping Duty Order... FR 47190 (September 15, 2009). Surrogate Country and Surrogate Values On August 7, 2009, Nhat Duc submitted surrogate country comments, and on September 4, 2009, Nhat Duc submitted surrogate value data. No...

Endpoints and surrogate endpoints in colorectal cancer: a review of recent developments.

PubMed

Piedbois, Pascal; Buyse, Marc

2008-07-01

The purpose of this review is to discuss recently published work on endpoints for early and advanced colorectal cancer, as well as the statistical approaches used to validate surrogate endpoints. Most attempts to validate surrogate endpoints have estimated the correlation between the surrogate and the true endpoint, and between the treatment effects on these endpoints. The correlation approach has made it possible to validate disease-free survival and progression-free survival as acceptable surrogates for overall survival in early and advanced disease, respectively. The search for surrogate endpoints will intensify over the coming years. In parallel, efforts to either standardize or extend the endpoints or both will improve the reliability and relevance of clinical trial results.

Computer-Simulation Surrogates for Optimization: Application to Trapezoidal Ducts and Axisymmetric Bodies

NASA Technical Reports Server (NTRS)

Otto, John C.; Paraschivoiu, Marius; Yesilyurt, Serhat; Patera, Anthony T.

1995-01-01

Engineering design and optimization efforts using computational systems rapidly become resource intensive. The goal of the surrogate-based approach is to perform a complete optimization with limited resources. In this paper we present a Bayesian-validated approach that informs the designer as to how well the surrogate performs; in particular, our surrogate framework provides precise (albeit probabilistic) bounds on the errors incurred in the surrogate-for-simulation substitution. The theory and algorithms of our computer{simulation surrogate framework are first described. The utility of the framework is then demonstrated through two illustrative examples: maximization of the flowrate of fully developed ow in trapezoidal ducts; and design of an axisymmetric body that achieves a target Stokes drag.

Inhibitory effects of KN-93, an inhibitor of Ca2+ calmodulin-dependent protein kinase II, on light-regulated root gravitropism in maize

NASA Technical Reports Server (NTRS)

Feldman, L. J.; Hidaka, H.

1993-01-01

Light is essential for root gravitropism in Zea mays L., cultivar Merit. It is hypothesized that calcium mediates this light-regulated response. KN-93, an inhibitor of calcium/calmodulin kinase II (CaMK II), inhibits light-regulated root gravitropism but does not affect light perception. We hypothesize that CaMK II, or a homologue, operates late in the light/gravity signal transduction chain. Here we provide evidence suggesting a possible physiological involvement of CaMK II in root gravitropism in plants.

Benthic Light Availability Improves Predictions of Riverine Primary Production

NASA Astrophysics Data System (ADS)

Kirk, L.; Cohen, M. J.

2017-12-01

Light is a fundamental control on photosynthesis, and often the only control strongly correlated with gross primary production (GPP) in streams and rivers; yet it has received far less attention than nutrients. Because benthic light is difficult to measure in situ, surrogates such as open sky irradiance are often used. Several studies have now refined methods to quantify canopy and water column attenuation of open sky light in order to estimate the amount of light that actually reaches the benthos. Given the additional effort that measuring benthic light requires, we should ask if benthic light always improves our predictions of GPP compared to just open sky irradiance. We use long-term, high-resolution dissolved oxygen, turbidity, dissolved organic matter (fDOM), and irradiance data from streams and rivers in north-central Florida, US across gradients of size and color to build statistical models of benthic light that predict GPP. Preliminary results on a large, clear river show only modest model improvements over open sky irradiance, even in heavily canopied reaches with pulses of tannic water. However, in another spring-fed river with greater connectivity to adjacent wetlands - and hence larger, more frequent pulses of tannic water - the model improved dramatically with the inclusion of fDOM (model R2 improved from 0.28 to 0.68). River shade modeling efforts also suggest that knowing benthic light will greatly enhance our ability to predict GPP in narrower, forested streams flowing in particular directions. Our objective is to outline conditions where an assessment of benthic light conditions would be necessary for riverine metabolism studies or management strategies.

Effect of low electric fields on alpha scintillation light yield in liquid argon

DOE PAGES

Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; ...

2017-01-24

Measurements were made of scintillation light yield of alpha particles from themore » $$^{222}$$Rn decay chain within the DarkSide-50 liquid argon time projection chamber. Furthermore, the light yield was found to increase as the applied electric field increased, with alphas in a 200 V/cm electric field exhibiting a 2% increase in light yield compared to alphas in no field.« less

Anisotropic Light Scattering from Ferrofluids

NASA Astrophysics Data System (ADS)

Rablau, Corneliu; Vaishnava, Prem; Naik, Ratna; Lawes, Gavin; Tackett, Ron; Sudakar, C.

2008-03-01

We have investigated the light scattering in DC magnetic fields from aqueous suspensions of Fe3O4 nanoparticles coated with tetra methyl ammonium hydroxide and γ-Fe2O3 nanoparticles embedded in alginate hydrogel. For Fe3O4 ferrofluid, anomalous light scattering behavior was observed when light propagated both parallel and perpendicular to the magnetic fields. This behavior is attributed to the alignment and aggregation of the nanoparticles in chain-like structures. A very different light scattering behavior was observed for γ-Fe2O3 alginate sample where, under the similar conditions, the application of the magnetic field produced no structured change in scattering. We attribute this difference to the absence of chain-like structures and constrained mobility of iron nanoparticles in the alginate sample. The observation is in agreement with our relaxation and dissipative heating results^1 where both samples exhibited Neel relaxation but only the Fe3O4 ferrofluid showed Brownian relaxation. The results suggest that Brownian relaxation and nanoparticle mobility are important for producing non-linear light scattering in such systems. ^1P.P. Vaishnava, R. Tackett, A. Dixit, C. Sudakar, R. Naik, and G. Lawes, J. Appl. Phys. 102, 063914 (2007).

Ammonium Assimilation Requires Mitochondrial Respiration in the Light 1

PubMed Central

Weger, Harold G.; Birch, Douglas G.; Elrifi, Ivor R.; Turpin, David H.

1988-01-01

Mass spectrometric analysis of O2 and CO2 exchange in the green alga Selenastrum minutum (Naeg. Collins) provides evidence for the occurrence of mitochondrial respiration in light. Stimulation of amino acid synthesis by the addition of NH4Cl resulted in nearly a 250% increase in the rate of TCA cycle CO2 efflux in both light and dark. Ammonium addition caused a similar increase in cyanide sensitive O2 consumption in both light and dark. Anaerobiosis inhibited the CO2 release caused by NH4Cl. These results indicated that the cytochrome pathway of the mitochondrial electron transport chain was operative and responsible for the oxidation of a large portion of the NADH generated during the ammonium induced increase in TCA cycle activity. In the presence of DCMU, ammonium addition also stimulated net O2 consumption in the light. This implied that the Mehler reaction did not play a significant role in O2 consumption under our conditions. These results show that both the TCA cycle and the mitochondrial electron transport chain are capable of operation in the light and that an important role of mitochondrial respiration in photosynthesizing cells is the provision of carbon skeletons for biosynthetic reactions. PMID:16665971

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

Villalba, Miryam I.; Canul-Tec, Juan C.; Luna-Martínez, Oscar D.

Light chain amyloidosis (AL) is a disease that affects vital organs by the fibrillar aggregation of monoclonal light chains. λ3r germ line is significantly implicated in this disease. In this paper, we contrasted the thermodynamic stability and aggregation propensity of 3mJL2 (nonamyloidogenic) and 3rJL2 (amyloidogenic) λ3 germ lines. Because of an inherent limitation (extremely low expression), Cys at position 34 of the 3r germ line was replaced by Tyr reaching a good expression yield. A second substitution (W91A) was introduced in 3r to obtain a better template to incorporate additional mutations. Although the single mutant (C34Y) was not fibrillogenic, themore » second mutation located at CDR3 (W91A) induced fibrillogenesis. We propose, for the first time, that CDR3 (position 91) affects the stability and fiber formation of human λ3r light chains. Using the double mutant (3rJL2/YA) as template, other variants were constructed to evaluate the importance of those substitutions into the stability and aggregation propensity of λ3 light chains. A change in position 7 (P7D) boosted 3rJL2/YA fibrillogenic properties. Modification of position 48 (I48M) partially reverted 3rJL2/YA fibril aggregation. Finally, changes at positions 8 (P8S) or 40 (P40S) completely reverted fibril formation. These results confirm the influential roles of N-terminal region (positions 7 and 8) and the loop 40–60 (positions 40 and 48) on AL. X-ray crystallography revealed that the three-dimensional topology of the single and double λ3r mutants was not significantly altered. Finally, this mutagenic approach helped to identify key regions implicated in λ3 AL.« less

Serum Free Light Chain Assay and κ/λ Ratio Performance in Patients Without Monoclonal Gammopathies:  High False-Positive Rate.

PubMed

Singh, Gurmukh

2016-08-01

Serum free light chain assay is a recommended screening test for monoclonal gammopathies. Anecdotal observations indicated a high rate of false-positive abnormal κ/λ ratios. This study was undertaken to ascertain the magnitude of the false-positive rate and factors contributing to the error rate. Results of serum protein electrophoresis, serum free light chains, and related tests, usually done for investigation of suspected monoclonal gammopathy, were reviewed retrospectively for 270 patients and 297 observations. Using the conventional κ/λ ratio, 36.4% of the ratios were abnormal, in the absence of monoclonal gammopathy. When the renal κ/λ ratio was used, the rate of abnormal κ/λ ratios was 30.1%. In patients with a γ-globulin concentration of 1.6 g/dL or more, the usual κ/λ ratio was abnormal in 54.8% of the patients. Urine protein electrophoresis was used in 53 (19.6%) instances, whereas bone marrow examination was done in 65 (24.1%) cases. Usual κ/λ ratio was abnormal in 36.4% of the observations in patients without evidence of monoclonal gammopathy, and an abnormal κ/λ ratio should not be used as the sole indicator for diagnosis of neoplastic proliferation of the lympho-plasmacytic system. Hypergammaglobulinemia is associated with a higher rate of false-positive abnormal κ/λ ratios. Examination of urine for monoclonal immunoglobulins may be underused, and recommendations by some to use serum free light chain assay in place of, rather than as an adjunct to, urine electrophoresis are not warranted. © American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cerebrospinal Fluid and Neuroimaging Biomarker Abnormalities Suggest Early Neurological Injury in a Subset of Individuals During Primary HIV Infection

PubMed Central

Peluso, Michael J.; Meyerhoff, Dieter J.; Price, Richard W.; Peterson, Julia; Lee, Evelyn; Young, Andrew C.; Walter, Rudy; Fuchs, Dietmar; Brew, Bruce J.; Cinque, Paola; Robertson, Kevin; Hagberg, Lars; Zetterberg, Henrik; Gisslén, Magnus; Spudich, Serena

2013-01-01

Background. Cerebrospinal fluid (CSF) and neuroimaging abnormalities demonstrate neuronal injury during chronic AIDS, but data on these biomarkers during primary human immunodeficiency virus (HIV) infection is limited. Methods. We compared CSF concentrations of neurofilament light chain, t-tau, p-tau, amyloid precursor proteins, and amyloid-beta 42 in 92 subjects with primary HIV infection and 25 controls. We examined relationships with disease progression and neuroinflammation, neuropsychological testing, and proton-magnetic resonance spectroscopy (MRS)–based metabolites. Results. Neurofilament light chain was elevated in primary HIV infection compared with controls (P = .0004) and correlated with CSF neopterin (r = 0.38; P = .0005), interferon gamma-induced protein 10 (r = 0.39; P = .002), white blood cells (r = 0.32; P = .004), protein (r = 0.59; P < .0001), and CSF/plasma albumin ratio (r = 0.60; P < .0001). Neurofilament light chain correlated with decreased N-acteylaspartate/creatine and glutamate/creatine in the anterior cingulate (r = −0.35, P = .02; r = −0.40, P = .009, respectively), frontal white matter (r = −0.43, P = .003; r = −0.30, P = .048, respectively), and parietal gray matter (r = −0.43, P = .003; r = −0.47, P = .001, respectively). Beta-amyloid was elevated in the primary infection group (P = .0005) and correlated with time infected (r = 0.34; P = .003). Neither marker correlated with neuropsychological abnormalities. T-tau and soluble amyloid precursor proteins did not differ between groups. Conclusions. Elevated neurofilament light chain and its correlation with MRS-based metabolites suggest early neuronal injury in a subset of participants with primary HIV infection through mechanisms involving central nervous system inflammation. PMID:23460748

Functional Cardiac Recovery and Hematologic Response to Chemotherapy in Patients With Light-Chain Amyloidosis (from the Stanford University Amyloidosis Registry).

PubMed

Tuzovic, Mirela; Kobayashi, Yukari; Wheeler, Matthew; Barrett, Christopher; Liedtke, Michaela; Lafayette, Richard; Schrier, Stanley; Haddad, Francois; Witteles, Ronald

2017-10-15

Cardiac involvement is common in patients with light-chain (AL) amyloidosis and portends a poor prognosis, although little is known about the changes in cardiac mechanics after chemotherapy. We sought to explore the relation between amyloidosis staging and baseline cardiac mechanics and to investigate short-term changes in cardiac mechanics after chemotherapy. We identified 41 consecutive patients from the Stanford Amyloid Center who had echocardiograms and free light-chain values before and after chemotherapy, along with 40 age- and gender-matched controls. Echocardiographic assessment included left ventricular global longitudinal strain, E/e' ratio, and left atrial (LA) stiffness. Hematologic response to chemotherapy was defined as ≥50% reduction in the difference between the involved and the uninvolved free light chain (dFLC). The mean age was 66.9 ± 8.4 years and 66% were men. Before chemotherapy, global longitudinal strain, E/e' ratio, and LA stiffness were impaired in patients with amyloidosis compared with controls, and the severity of impairment worsened with advanced staging. After chemotherapy, hematologic response was observed in 30 (73%) patients. There was a significant association between the change in dFLC and cardiac function (E/e' ratio: r = -0.43, p = 0.01; LA stiffness: r = -0.35, p = 0.05). There was no significant improvement in cardiac mechanics in patients without a hematologic response to chemotherapy. In conclusion, amyloidosis stage correlated with noninvasive measurements of cardiac mechanics, and improvement in dFLC correlated with cardiac improvement on short-term follow-up echocardiography. Copyright © 2017 Elsevier Inc. All rights reserved.

Localized conformational changes trigger the pH-induced fibrillogenesis of an amyloidogenic λ light chain protein.

PubMed

Velázquez-López, Isabel; Valdés-García, Gilberto; Romero Romero, Sergio; Maya Martínez, Roberto; Leal-Cervantes, Ana I; Costas, Miguel; Sánchez-López, Rosana; Amero, Carlos; Pastor, Nina; Fernández Velasco, D Alejandro

2018-07-01

Solvent conditions modulate the expression of the amyloidogenic potential of proteins. In this work the effect of pH on the fibrillogenic behavior and the conformational properties of 6aJL2, a model protein of the highly amyloidogenic variable light chain λ6a gene segment, was examined. Ordered aggregates showing the ultrastructural and spectroscopic properties observed in amyloid fibrils were formed in the 2.0-8.0 pH range. At pH <3.0 a drastic decrease in lag time and an increase in fibril formation rate were found. In the 4.0-8.0 pH range there was no spectroscopic evidence for significant conformational changes in the native state. Likewise, heat capacity measurements showed no evidence for residual structure in the unfolded state. However, at pH <3.0 stability is severely decreased and the protein suffers conformational changes as detected by circular dichroism, tryptophan and ANS fluorescence, as well as by NMR spectroscopy. Molecular dynamics simulations indicate that acid-induced conformational changes involve the exposure of the loop connecting strands E and F. These results are compatible with pH-induced changes in the NMR spectra. Overall, the results indicate that the mechanism involved in the acid-induced increase in the fibrillogenic potential of 6aJL2 is profoundly different to that observed in κ light chains, and is promoted by localized conformational changes in a region of the protein that was previously not known to be involved in acid-induced light chain fibril formation. The identification of this region opens the potential for the design of specific inhibitors. Copyright © 2018 Elsevier B.V. All rights reserved.

Photoswitching of ferroelectric liquid crystals using chiral thioindigo dopants: The development of a photochemical switch hitter.

PubMed

Lemieux, Robert P

2004-01-01

By virtue of its spontaneous polarization (PS), a ferroelectric SmC* liquid crystal can be switched between two states corresponding to opposite molecular tilt orientations using an electric field, thus producing an ON-OFF light shutter between crossed polarizers. Considerable efforts have been made over the past decade to develop photonic FLC light shutters because of their potential uses in dynamic holography and optical data storage. The ON-OFF switching of a FLC light shutter can be triggered by light via a photoinversion of PS using a photochromic dopant. The spontaneous polarization is a chiral bulk property that can be left-handed (negative) or right-handed (positive), depending on the absolute configuration of the chiral component of the SmC* phase. In the approach described herein, the magnitude of PS is modulated via the photoisomerization of a chiral thioindigo dopant that undergoes a large increase in transverse dipole moment upon trans-cis photoisomerization. The sign of PS is photoinverted using an "ambidextrous" thioindigo dopant containing a chiral 2-octyloxy side chain that is coupled to the thioindigo core and induces a positive PS, and a chiral 2,3-difluorooctyloxy side chain that is decoupled from the core and induces a negative PS. In the trans form, the 2,3-difluorooctyloxy side chain predominates and the net PS induced by the dopant is negative. However, upon trans-cis-photoisomerization, the increase in transverse dipole moment of the 2-octyloxy/thioindigo unit raises its induced PS over that of the decoupled 2,3-difluorooctyloxy side chain, and thus inverts the net sign of PS induced by the dopant from negative to positive. Copyright 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

Definitions and validation criteria for biomarkers and surrogate endpoints: development and testing of a quantitative hierarchical levels of evidence schema.

PubMed

Lassere, Marissa N; Johnson, Kent R; Boers, Maarten; Tugwell, Peter; Brooks, Peter; Simon, Lee; Strand, Vibeke; Conaghan, Philip G; Ostergaard, Mikkel; Maksymowych, Walter P; Landewe, Robert; Bresnihan, Barry; Tak, Paul-Peter; Wakefield, Richard; Mease, Philip; Bingham, Clifton O; Hughes, Michael; Altman, Doug; Buyse, Marc; Galbraith, Sally; Wells, George

2007-03-01

There are clear advantages to using biomarkers and surrogate endpoints, but concerns about clinical and statistical validity and systematic methods to evaluate these aspects hinder their efficient application. Our objective was to review the literature on biomarkers and surrogates to develop a hierarchical schema that systematically evaluates and ranks the surrogacy status of biomarkers and surrogates; and to obtain feedback from stakeholders. After a systematic search of Medline and Embase on biomarkers, surrogate (outcomes, endpoints, markers, indicators), intermediate endpoints, and leading indicators, a quantitative surrogate validation schema was developed and subsequently evaluated at a stakeholder workshop. The search identified several classification schema and definitions. Components of these were incorporated into a new quantitative surrogate validation level of evidence schema that evaluates biomarkers along 4 domains: Target, Study Design, Statistical Strength, and Penalties. Scores derived from 3 domains the Target that the marker is being substituted for, the Design of the (best) evidence, and the Statistical strength are additive. Penalties are then applied if there is serious counterevidence. A total score (0 to 15) determines the level of evidence, with Level 1 the strongest and Level 5 the weakest. It was proposed that the term "surrogate" be restricted to markers attaining Levels 1 or 2 only. Most stakeholders agreed that this operationalization of the National Institutes of Health definitions of biomarker, surrogate endpoint, and clinical endpoint was useful. Further development and application of this schema provides incentives and guidance for effective biomarker and surrogate endpoint research, and more efficient drug discovery, development, and approval.

Validation of surrogate endpoints in cancer clinical trials via principal stratification with an application to a prostate cancer trial.

PubMed

Tanaka, Shiro; Matsuyama, Yutaka; Ohashi, Yasuo

2017-08-30

Increasing attention has been focused on the use and validation of surrogate endpoints in cancer clinical trials. Previous literature on validation of surrogate endpoints are classified into four approaches: the proportion explained approach; the indirect effects approach; the meta-analytic approach; and the principal stratification approach. The mainstream in cancer research has seen the application of a meta-analytic approach. However, VanderWeele (2013) showed that all four of these approaches potentially suffer from the surrogate paradox. It was also shown that, if a principal surrogate satisfies additional criteria called one-sided average causal sufficiency, the surrogate cannot exhibit a surrogate paradox. Here, we propose a method for estimating principal effects under a monotonicity assumption. Specifically, we consider cancer clinical trials which compare a binary surrogate endpoint and a time-to-event clinical endpoint under two naturally ordered treatments (e.g. combined therapy vs. monotherapy). Estimation based on a mean score estimating equation will be implemented by the expectation-maximization algorithm. We will also apply the proposed method as well as other surrogacy criteria to evaluate the surrogacy of prostate-specific antigen using data from a phase III advanced prostate cancer trial, clarifying the complementary roles of both the principal stratification and meta-analytic approaches in the evaluation of surrogate endpoints in cancer. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Evaluating Candidate Principal Surrogate Endpoints

PubMed Central

Gilbert, Peter B.; Hudgens, Michael G.

2009-01-01

Summary Frangakis and Rubin (2002, Biometrics 58, 21–29) proposed a new definition of a surrogate endpoint (a “principal” surrogate) based on causal effects. We introduce an estimand for evaluating a principal surrogate, the causal effect predictiveness (CEP) surface, which quantifies how well causal treatment effects on the biomarker predict causal treatment effects on the clinical endpoint. Although the CEP surface is not identifiable due to missing potential outcomes, it can be identified by incorporating a baseline covariate(s) that predicts the biomarker. Given case–cohort sampling of such a baseline predictor and the biomarker in a large blinded randomized clinical trial, we develop an estimated likelihood method for estimating the CEP surface. This estimation assesses the “surrogate value” of the biomarker for reliably predicting clinical treatment effects for the same or similar setting as the trial. A CEP surface plot provides a way to compare the surrogate value of multiple biomarkers. The approach is illustrated by the problem of assessing an immune response to a vaccine as a surrogate endpoint for infection. PMID:18363776

Identifying experimental surrogates for Bacillus anthracis spores: a review

PubMed Central

2010-01-01

Bacillus anthracis, the causative agent of anthrax, is a proven biological weapon. In order to study this threat, a number of experimental surrogates have been used over the past 70 years. However, not all surrogates are appropriate for B. anthracis, especially when investigating transport, fate and survival. Although B. atrophaeus has been widely used as a B. anthracis surrogate, the two species do not always behave identically in transport and survival models. Therefore, we devised a scheme to identify a more appropriate surrogate for B. anthracis. Our selection criteria included risk of use (pathogenicity), phylogenetic relationship, morphology and comparative survivability when challenged with biocides. Although our knowledge of certain parameters remains incomplete, especially with regards to comparisons of spore longevity under natural conditions, we found that B. thuringiensis provided the best overall fit as a non-pathogenic surrogate for B. anthracis. Thus, we suggest focusing on this surrogate in future experiments of spore fate and transport modelling. PMID:21092338

The characteristics of brown carbon aerosol during winter in Beijing

NASA Astrophysics Data System (ADS)

Cheng, Yuan; He, Ke-bin; Du, Zhen-yu; Engling, Guenter; Liu, Jiu-meng; Ma, Yong-liang; Zheng, Mei; Weber, Rodney J.

2016-02-01

Brown carbon (i.e., light-absorbing organic carbon, or BrC) exerts important effects on the environment and on climate in particular. Based on spectrophotometric absorption measurements on extracts of bulk aerosol samples, this study investigated the characteristics of BrC during winter in Beijing, China. Organic compounds extractable by methanol contributed approximately 85% to the organic carbon (OC) mass. Light absorption by the methanol extracts exhibited a strong wavelength dependence, with an average absorption Ångström exponent of 7.10 (fitted between 310 and 450 nm). Normalizing the absorption coefficient (babs) measured at 365 nm to the extractable OC mass yielded an average mass absorption efficiency (MAE) of 1.45 m2/g for the methanol extracts. This study suggests that light absorption by BrC could be comparable with black carbon in the spectral range of near-ultraviolet light. Our results also indicate that BrC absorption and thus BrC radiative forcing could be largely underestimated when using water-soluble organic carbon (WSOC) as a surrogate for BrC. Compared to previous work relying only on WSOC, this study provides a more comprehensive understanding of BrC aerosol based on methanol extraction.

Identification of human antibody fragment clones specific for tetanus toxoid in a bacteriophage. lambda. immunoexpression library

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

Mullinax, R.L.; Gross, E.A.; Amberg, J.R.

1990-10-01

The authors have applied a molecular biology approach to the identification of human monoclonal antibodies. Human peripheral blood lymphocyte mRNA was converted to cDNA and a select subset was amplified by the polymerase chain reaction. These products, containing coding sequences for numerous immunoglobulin heavy- and {kappa} light-chain variable and constant region domains, were inserted into modified bacteriophase {lambda} expression vectors and introduced into Escherichia coli by infection to yield a combinatorial immunoexpression library. Clones with binding activity to tetanus toxoid were identified by filter hybridization with radiolabeled antigen and appeared at a frequency of 0.2{percent} in the library. These humanmore » antigen binding fragments, consisting of a heavy-chain fragment covalently linked to a light chain, displayed high affinity of binding to tetanus toxoid with equilibrium constants in the nanomolar range but did not cross-react with other proteins tested. They estimate that this human immunoexpression library contains 20,000 clones with high affinity and specificity to our chosen antigen.« less

Flow cytometric analysis of immunoglobulin heavy chain expression in B-cell lymphoma and reactive lymphoid hyperplasia

PubMed Central

Grier, David D; Al-Quran, Samer Z; Cardona, Diana M; Li, Ying; Braylan, Raul C

2012-01-01

The diagnosis of B-cell lymphoma (BCL) is often dependent on the detection of clonal immunoglobulin (Ig) light chain expression. In some BCLs, the determination of clonality based on Ig light chain restriction may be difficult. The aim of our study was to assess the utility of flow cytometric analysis of surface Ig heavy chain (HC) expression in lymphoid tissues in distinguishing lymphoid hyperplasias from BCLs, and also differentiating various BCL subtypes. HC expression on B-cells varied among different types of hyperplasias. In follicular hyperplasia, IgM and IgD expression was high in mantle cells while germinal center cells showed poor HC expression. In other hyperplasias, B cell compartments were blurred but generally showed high IgD and IgM expression. Compared to hyperplasias, BCLs varied in IgM expression. Small lymphocytic lymphomas had lower IgM expression than mantle cell lymphomas. Of importance, IgD expression was significantly lower in BCLs than in hyperplasias, a finding that can be useful in differentiating lymphoma from reactive processes. PMID:22400070

Modeling water clarity in oceans and coasts

EPA Science Inventory

In oceans and coastal waters, phytoplankton is the primary producer of organic compounds which form the base for the food chain. The concentration of phytoplankton is a major factor controlling water clarity and the depth to which light penetrates in the water column. The light i...

Ultraviolet-C Light Sanitization of English Cucumber (Cucumis sativus) Packaged in Polyethylene Film.

PubMed

Tarek, Abdussamad R; Rasco, Barbara A; Sablani, Shyam S

2016-06-01

Food safety is becoming an increasing concern in the United States. This study investigated the effects of ultraviolet-C (UV-C) light as a postpackaging bactericidal treatment on the quality of English cucumber packaged in polyethylene (PE) film. Escherichia coli k-12 was used as a surrogate microbe. The microbial growth and physical properties of packaged cucumbers were analyzed during a 28-d storage period at 5 °C. Inoculating packaged cucumbers treated at 23 °C for 6 min with UV-C (560 mJ/cm(2) ) resulted in a 1.60 log CFU/g reduction. However, this treatment had no significant effect (P > 0.05) on the water vapor transmission rate or oxygen transmission rate of the PE film. Results show that UV-C light treatment delayed the loss of firmness and yellowing of English cucumber up to 28 d at 5 °C. In addition, UV-C light treatment extended the shelf life of treated cucumber 1 wk longer compared to untreated cucumbers. Electron microscopy images indicate that UV-C light treatment influences the morphology of the E. coli k-12 cells. Findings demonstrate that treating cucumbers with UV-C light following packaging in PE film can reduce bacterial populations significantly and delay quality loss. This technology may also be effective for other similarly packaged fresh fruits and vegetables. © 2016 Institute of Food Technologists®

Tetanus toxin is labeled with photoactivatable phospholipids at low pH

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

Montecucco, C.; Schiavo, G.; Brunner, J.

1986-02-25

The mechanism of cell penetration by tetanus toxin is unknown; it has been suggested that the toxin may penetrate into the lipid bilayer from a low-pH vesicular compartment. In this work, the interaction of tetanus toxin with liposomal model membranes has been studied by following its photoinduced cross-linking with either a nitrene or a carbene photolytically generated from corresponding light-sensitive phosphatidylcholine analogues. The toxin was labeled only at pHs lower than 5.5. The low pH acquired hydrophobicity of tetanus toxin appears to be confined to its light chain and to the 45-kDa NH2-terminal fragment of the heavy chain. Negatively chargedmore » lipids promote the interaction of this toxin with the hydrocarbon chain of phospholipids. The relevance of the present findings to the possible mechanism of nerve cell penetration by tetanus toxin is discussed.« less

Focused Evolution of HIV-1 Neutralizing Antibodies Revealed by Structures and Deep Sequencing

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

Wu, Xueling; Zhou, Tongqing; Zhu, Jiang

2013-03-04

Antibody VRC01 is a human immunoglobulin that neutralizes about 90% of HIV-1 isolates. To understand how such broadly neutralizing antibodies develop, we used x-ray crystallography and 454 pyrosequencing to characterize additional VRC01-like antibodies from HIV-1-infected individuals. Crystal structures revealed a convergent mode of binding for diverse antibodies to the same CD4-binding-site epitope. A functional genomics analysis of expressed heavy and light chains revealed common pathways of antibody-heavy chain maturation, confined to the IGHV1-2*02 lineage, involving dozens of somatic changes, and capable of pairing with different light chains. Broadly neutralizing HIV-1 immunity associated with VRC01-like antibodies thus involves the evolution ofmore » antibodies to a highly affinity-matured state required to recognize an invariant viral structure, with lineages defined from thousands of sequences providing a genetic roadmap of their development.« less

The Viscoelastic Properties of Nematic Monodomains Containing Liquid Crystal Polymers.

NASA Astrophysics Data System (ADS)

Gu, Dongfeng

The work presented here investigates the viscoelastic properties of nematic materials containing liquid crystal polymers (LCP). We focus on how the elastic constants and the viscosity coefficients of the mixture systems are influenced by polymer architectures. In dynamic light scattering studies of the relaxation of the director orientation fluctuations for the splay, twist, and bend deformation modes, decrease of the relaxation rates was observed when LCPs were dissolved into low molar mass nematics (LMMN). For the side-chain LCPs, the slowing down in the bend mode is comparable to or larger than those of the splay and twist modes. For main-chain LCPs, the relative changes in the relaxation rates for the twist and splay modes are about one order of magnitude larger than that for the bend mode. The results of light scattering under an electric field show that the decrease in the twist relaxation rate is due to a large increase in the twist viscosity and a minor decrease in the twist elastic constant. These changes were found to increase with decrease of the spacer length, with increase of molecular weight, and with decrease of the backbone flexibility. In Freedericksz transition measurements, the splay and bend elastic constants and the dielectric anisotropies of the nematic mixtures were determined and the values are 5~15% lower than those of the pure solvent. From the analysis of the results of Freedericksz transition and light scattering experiments, a complete set of the elastic constants and viscosity coefficients corresponding to the three director deformation modes were obtained for the LCP mixtures. The changes in the viscosity coefficients due to addition of LCPs were analysed to estimate the anisotropic shapes of the polymer backbone via a hydrodynamic model. The results suggest that an oblate backbone configuration is maintained by the side-chain LCPs and a prolate chain configuration appears for the main-chain LCPs. The rheological behavior of a side-chain and a main-chain LCP nematic solutions were investigated. The addition of the side-chain LCP into a flow-aligning LMMN (5CB) induces director tumbling in the mixture, and, the dissolution of the main-chain LCP into a director tumbling LMMN (8CB) makes the solution become a flow-aligning nematic. Based on the hydrodynamic theory, these observations are further confirmation of the chain anisotropies of the LCPs investigated. Ericksen's transversely isotropic fluid model was used to extract the various viscosity coefficients with good accuracy. In addition, we believe that this is the first time the bulk rheological consequences of director tumbling in LMMNs has been observed.

Surrogate endpoints for overall survival in advanced colorectal cancer: a clinician's perspective.

PubMed

Piedbois, Pascal; Miller Croswell, Jennifer

2008-10-01

Surrogate endpoints in oncology research and practice have garnered increasing attention over the past two decades. This activity has largely been driven by the promise surrogate endpoints appear to hold: the potential to get new therapies to seriously ill patients more rapidly. However, uncertainties abound. Even agreeing upon a definition of a "valid" surrogate endpoint has not been a straightforward exercise; this article begins by highlighting differences in how this term has been previously captured and applied, as well as laying out the basic criteria essential for its application in advanced colorectal cancer. Ideally, these elements include (but are not limited to) ease of measurement, rapid indication of treatment effect, and, most importantly, reliable and consistent prediction of the true impact of a treatment on the ultimate outcome of interest: overall survival. The strengths and weaknesses of current potential surrogate endpoints in advanced colorectal cancer, including performance status, carcinoembryonic antigen plasma level, overall response rate, time to progression, and disease-free survival, are each considered in turn. Finally, limitations of surrogate endpoints in the clinical setting, including challenges in extrapolation to new therapies, and the incomplete provision of information about potential adverse effects, are discussed. Work remains to be done between physicians and statisticians to bridge the gap between that which is statistically demonstrable and that which will be clinically useful.The term ;surrogate endpoint' was virtually unknown by most oncologists 15 years ago. A search in PubMed [http://www.ncbi.nlm.nih.gov] based on the words ;surrogate and cancer' shows that more than 2000 papers were published in medical journals in the last 20 years, with a dramatic increase of interest in the last five years. Interestingly, the same trend is observed when the words ;surrogate and heart' are entered into PubMed, suggesting that the issue of surrogate endpoints goes beyond the field of oncology, although the frequency of discussion varies (Figure 1; note different y-axis scales for oncology and cardiology).The goal of the present paper is to discuss the main issues surrounding surrogate endpoints from a clinician's point of view, using as an example surrogate endpoints of overall survival (OS) in advanced colorectal cancer (ACC).

Exploitation in International Paid Surrogacy Arrangements.

PubMed

Wilkinson, Stephen

2016-05-01

Many critics have suggested that international paid surrogacy is exploitative. Taking such concerns as its starting point, this article asks: (1) how defensible is the claim that international paid surrogacy is exploitative and what could be done to make it less exploitative? (2) In the light of the answer to (1), how strong is the case for prohibiting it? Exploitation could in principle be dealt with by improving surrogates' pay and conditions. However, doing so may exacerbate problems with consent. Foremost amongst these is the argument that surrogates from economically disadvantaged countries cannot validly consent because their background circumstances are coercive. Several versions of this argument are examined and I conclude that at least one has some merit. The article's overall conclusion is that while ethically there is something to be concerned about, paid surrogacy is in no worse a position than many other exploitative commercial transactions which take place against a backdrop of global inequality and constrained options, such as poorly-paid and dangerous construction work. Hence, there is little reason to single surrogacy out for special condemnation. On a policy level, the case for prohibiting international commercial surrogacy is weak, despite legitimate concerns about consent and background poverty.

Exploitation in International Paid Surrogacy Arrangements

PubMed Central

Wilkinson, Stephen

2015-01-01

Abstract Many critics have suggested that international paid surrogacy is exploitative. Taking such concerns as its starting point, this article asks: (1) how defensible is the claim that international paid surrogacy is exploitative and what could be done to make it less exploitative? (2) In the light of the answer to (1), how strong is the case for prohibiting it? Exploitation could in principle be dealt with by improving surrogates' pay and conditions. However, doing so may exacerbate problems with consent. Foremost amongst these is the argument that surrogates from economically disadvantaged countries cannot validly consent because their background circumstances are coercive. Several versions of this argument are examined and I conclude that at least one has some merit. The article's overall conclusion is that while ethically there is something to be concerned about, paid surrogacy is in no worse a position than many other exploitative commercial transactions which take place against a backdrop of global inequality and constrained options, such as poorly‐paid and dangerous construction work. Hence, there is little reason to single surrogacy out for special condemnation. On a policy level, the case for prohibiting international commercial surrogacy is weak, despite legitimate concerns about consent and background poverty. PMID:27471338

Developing the (d,p γ) reaction as a surrogate for (n, γ) in inverse kinematics

NASA Astrophysics Data System (ADS)

Lepailleur, Alexandr; Sims, Harry; Garland, Heather; Baugher, Travis; Cizewski, Jolie A.; Ratkiewicz, Andrew; Walter, Daivid; Pain, Steven D.; Smith, Karl; Goddess Collaboration Collaboration

2017-09-01

The r-process that proceeds via (n, γ) reactions on neutron-rich nuclei is responsible for the synthesis of about half of the elements heavier than iron. Because (n, γ) measurements on short-lived isotopes are not possible, the (d,p γ) reaction is being investigated as a surrogate for (n, γ) . The experimental setup GODDESS (Gammasphere ORRUBA: Dual Detectors for Experimental Structure Studies) has been developed especially for this purpose. The Oak Ridge Rutgers University Barrel Array (ORRUBA) of position-sensitive silicon strip detectors was augmented with annular arrays of segmented strip detectors at backward and forward angles, resulting in a high-angular coverage for light ejectiles (20 to 160 degrees in the laboratory frame). The 134Xe(d,p γ) reaction, used to commission the setup, was measured in inverse kinematics with stable beams from ATLAS impinged on C2D4 targets. Reaction protons were measured (ORRUBA) in coincidence with gamma rays (Gammasphere). An overview of GODDESS and preliminary results from the 134Xe(d,p γ) study will be presented. Work supported in part by U.S. D.O.E. and National Science Foundation.

Environmental diversity as a surrogate for species representation.

PubMed

Beier, Paul; de Albuquerque, Fábio Suzart

2015-10-01

Because many species have not been described and most species ranges have not been mapped, conservation planners often use surrogates for conservation planning, but evidence for surrogate effectiveness is weak. Surrogates are well-mapped features such as soil types, landforms, occurrences of an easily observed taxon (discrete surrogates), and well-mapped environmental conditions (continuous surrogate). In the context of reserve selection, the idea is that a set of sites selected to span diversity in the surrogate will efficiently represent most species. Environmental diversity (ED) is a rarely used surrogate that selects sites to efficiently span multivariate ordination space. Because it selects across continuous environmental space, ED should perform better than discrete surrogates (which necessarily ignore within-bin and between-bin heterogeneity). Despite this theoretical advantage, ED appears to have performed poorly in previous tests of its ability to identify 50 × 50 km cells that represented vertebrates in Western Europe. Using an improved implementation of ED, we retested ED on Western European birds, mammals, reptiles, amphibians, and combined terrestrial vertebrates. We also tested ED on data sets for plants of Zimbabwe, birds of Spain, and birds of Arizona (United States). Sites selected using ED represented European mammals no better than randomly selected cells, but they represented species in the other 7 data sets with 20% to 84% effectiveness. This far exceeds the performance in previous tests of ED, and exceeds the performance of most discrete surrogates. We believe ED performed poorly in previous tests because those tests considered only a few candidate explanatory variables and used suboptimal forms of ED's selection algorithm. We suggest future work on ED focus on analyses at finer grain sizes more relevant to conservation decisions, explore the effect of selecting the explanatory variables most associated with species turnover, and investigate whether nonclimate abiotic variables can provide useful surrogates in an ED framework. © 2015 Society for Conservation Biology.

Best Practicable Aggregation of Species: a step forward for species surrogacy in environmental assessment and monitoring

PubMed Central

Bevilacqua, Stanislao; Claudet, Joachim; Terlizzi, Antonio

2013-01-01

The available taxonomic expertise and knowledge of species is still inadequate to cope with the urgent need for cost-effective methods to quantifying community response to natural and anthropogenic drivers of change. So far, the mainstream approach to overcome these impediments has focused on using higher taxa as surrogates for species. However, the use of such taxonomic surrogates often limits inferences about the causality of community patterns, which in turn is essential for effective environmental management strategies. Here, we propose an alternative approach to species surrogacy, the “Best Practicable Aggregation of Species” (BestAgg), in which surrogates exulate from fixed taxonomic schemes. The approach uses null models from random aggregations of species to minimizing the number of surrogates without causing significant losses of information on community patterns. Surrogate types are then selected in order to maximize ecological information. We applied the approach to real case studies on natural and human-driven gradients from marine benthic communities. Outcomes from BestAgg were also compared with those obtained using classic taxonomic surrogates. Results showed that BestAgg surrogates are effective in detecting community changes. In contrast to classic taxonomic surrogates, BestAgg surrogates allow retaining significantly higher information on species-level community patterns than what is expected to occur by chance and a potential time saving during sample processing up to 25% higher. Our findings showed that BestAgg surrogates from a pilot study could be used successfully in similar environmental investigations in the same area, or for subsequent long-term monitoring programs. BestAgg is virtually applicable to any environmental context, allowing exploiting multiple surrogacy schemes beyond stagnant perspectives strictly relying on taxonomic relatedness among species. This prerogative is crucial to extend the concept of species surrogacy to ecological traits of species, thus leading to ecologically meaningful surrogates that, while cost effective in reflecting community patterns, may also contribute to unveil underlying processes. A specific R code for BestAgg is provided. PMID:24198939

Observation of Burial and Migration of Instrumented Surrogate Munitions Deployed in the Swash Zone

NASA Astrophysics Data System (ADS)

Cristaudo, D.; Puleo, J. A.; Bruder, B. L.

2017-12-01

Munitions (also known as unexploded ordnance; UXO) in the nearshore environment due to past military activities, may be found on the beach, constituting a risk for beach users. Munitions may be transported from offshore to shallower water and/or migrate along the coast. In addition, munitions may bury in place or be exhumed due to hydrodynamic forcing. Observations on munitions mobility have generally been collected offshore, while observations in the swash zone are scarce. The swash zone is the region of the beach alternately covered by wave runup where hydrodynamic processes may be intense. Studies of munitions mobility require the use of realistic surrogates to quantify mobility/burial and hydrodynamic forcing conditions. Four surrogates (BLU-61 Cluster Bomb, 81 mm Mortar, M151-70 Hydra Rocket and M107 155 mm High Explosive Howitzer) were developed and tested during large-scale laboratory and field studies. Surrogates house sensors that measure different components of motion. Errors between real munitions and surrogate parameters (mass, center of gravity and axial moment of inertia) are all within an absolute error of 20%. Internal munitions sensors consist of inertial motion units (for acceleration and angular velocity in and around the three directions and orientation), pressure transducers (for water depth above surrogate), shock recorders (for high frequency acceleration to detect wave impact on the surrogate), and an in-house designed array of optical sensors (for burial/exposure and rolling). An in situ array of sensors to measure hydrodynamics, bed morphology and sediment concentrations, was deployed in the swash zone, aligned with the surrogate deployment. Data collected during the studies will be shown highlighting surrogate sensor capabilities. Sensors response will be compared with GPS measurements and imagery from cameras overlooking the study sites of surrogate position as a function of time. Examples of burial/exposure and migration of surrogates will be discussed. Relationships between burial/migration and incoming forcing conditions, bed slope and munitions characteristics (such as specific density, length/diameter) will all be shown.

Light-induced phosphorylation of a membrane protein plays an early role in signal transduction for phototropism in Arabidopsis thaliana

NASA Technical Reports Server (NTRS)

Reymond, P.; Short, T. W.; Briggs, W. R.; Poff, K. L.

1992-01-01

Blue light is known to cause rapid phosphorylation of a membrane protein in etiolated seedlings of several plant species, a protein that, at least in etiolated pea seedlings and maize coleoptiles, has been shown to be associated with the plasma membrane. The light-driven phosphorylation has been proposed on the basis of correlative evidence to be an early step in the signal transduction chain for phototropism. In the Arabidopsis thaliana mutant JK224, the sensitivity to blue light for induction of first positive phototropism is known to be 20- to 30-fold lower than in wild type, whereas second positive curvature appears to be normal. While light-induced phosphorylation can be demonstrated in crude membrane preparations from shoots of the mutant, the level of phosphorylation is dramatically lower than in wild type, as is the sensitivity to blue light. Another A. thaliana mutant, JK218, that completely lacks any phototropic responses to up to 2 h of irradiation, shows a normal level of light-induced phosphorylation at saturation. Since its gravitropic sensitivity is normal, it is presumably blocked in some step between photoreception and the confluence of the signal transduction pathways for phototropism and gravitropism. We conclude from mutant JK224 that light-induced phosphorylation plays an early role in the signal transduction chain for phototropism in higher plants.

Decorin causes autophagy in endothelial cells via Peg3

PubMed Central

Buraschi, Simone; Neill, Thomas; Goyal, Atul; Poluzzi, Chiara; Smythies, James; Owens, Rick T.; Schaefer, Liliana; Torres, Annabel; Iozzo, Renato V.

2013-01-01

Soluble decorin affects the biology of several receptor tyrosine kinases by triggering receptor internalization and degradation. We found that decorin induced paternally expressed gene 3 (Peg3), an imprinted tumor suppressor gene, and that Peg3 relocated into autophagosomes labeled by Beclin 1 and microtubule-associated light chain 3. Decorin evoked Peg3-dependent autophagy in both microvascular and macrovascular endothelial cells leading to suppression of angiogenesis. Peg3 coimmunoprecipitated with Beclin 1 and LC3 and was required for maintaining basal levels of Beclin 1. Decorin, via Peg3, induced transcription of Beclin 1 and microtubule-associated protein 1 light chain 3 alpha genes, thereby leading to a protracted autophagic program. Mechanistically, decorin interacted with VEGF receptor 2 (VEGFR2) in a region overlapping with its natural ligand VEGFA, and VEGFR2 was required for decorin-evoked Beclin 1 and microtubule-associated protein 1 light chain 3 alpha expression as well as for Peg3 induction in endothelial cells. Moreover, decorin induced VEGFR2-dependent mitochondrial fragmentation and loss of mitochondrial membrane potential. Thus, we have unveiled a mechanism for a secreted proteoglycan in inducing Peg3, a master regulator of macroautophagy in endothelial cells. PMID:23798385

Risk factors for venous thromboembolism in immunoglobulin light chain amyloidosis

PubMed Central

Bever, Katherine M.; Masha, Luke I.; Sun, Fangui; Stern, Lauren; Havasi, Andrea; Berk, John L.; Sanchorawala, Vaishali; Seldin, David C.; Sloan, J. Mark

2016-01-01

Patients with immunoglobulin light chain amyloidosis are at risk for both thrombotic and bleeding complications. While the hemostatic defects have been extensively studied, less is known about thrombotic complications in this disease. This retrospective study examined the frequency of venous thromboembolism in 929 patients with immunoglobulin light chain amyloidosis presenting to a single referral center, correlated risk of venous thromboembolism with clinical and laboratory factors, and examined complications of anticoagulation in this population. Sixty-five patients (7%) were documented as having at least one venous thromboembolic event. Eighty percent of these patients had events within one year prior to or following diagnosis. Lower serum albumin was associated with increased risk of VTE, with a hazard ratio of 4.30 (CI 1.60–11.55; P=0.0038) for serum albumin less than 3 g/dL compared to serum albumin greater than 4 g/dL. Severe bleeding complications were observed in 5 out of 57 patients with venous thromboembolism undergoing treatment with anticoagulation. Prospective investigation should be undertaken to better risk stratify these patients and to determine the optimal strategies for prophylaxis against and management of venous thromboembolism. PMID:26452981

Risk factors for venous thromboembolism in immunoglobulin light chain amyloidosis.

PubMed

Bever, Katherine M; Masha, Luke I; Sun, Fangui; Stern, Lauren; Havasi, Andrea; Berk, John L; Sanchorawala, Vaishali; Seldin, David C; Sloan, J Mark

2016-01-01

Patients with immunoglobulin light chain amyloidosis are at risk for both thrombotic and bleeding complications. While the hemostatic defects have been extensively studied, less is known about thrombotic complications in this disease. This retrospective study examined the frequency of venous thromboembolism in 929 patients with immunoglobulin light chain amyloidosis presenting to a single referral center, correlated risk of venous thromboembolism with clinical and laboratory factors, and examined complications of anticoagulation in this population. Sixty-five patients (7%) were documented as having at least one venous thromboembolic event. Eighty percent of these patients had events within one year prior to or following diagnosis. Lower serum albumin was associated with increased risk of VTE, with a hazard ratio of 4.30 (CI 1.60-11.55; P=0.0038) for serum albumin less than 3 g/dL compared to serum albumin greater than 4 g/dL. Severe bleeding complications were observed in 5 out of 57 patients with venous thromboembolism undergoing treatment with anticoagulation. Prospective investigation should be undertaken to better risk stratify these patients and to determine the optimal strategies for prophylaxis against and management of venous thromboembolism. Copyright© Ferrata Storti Foundation.

Renal complications in multiple myeloma and related disorders: survivorship care plan of the International Myeloma Foundation Nurse Leadership Board.

PubMed

Faiman, Beth M; Mangan, Patricia; Spong, Jacy; Tariman, Joseph D

2011-08-01

Kidney dysfunction is a common clinical feature of symptomatic multiple myeloma. Some degree of renal insufficiency or renal failure is present at diagnosis or will occur during the course of the disease and, if not reversed, will adversely affect overall survival and quality of life. Chronic insults to the kidneys from other illnesses, treatment, or multiple myeloma itself can further damage renal function and increase the risk for additional complications, such as anemia. Patients with multiple myeloma who have light chain (Bence Jones protein) proteinuria may experience renal failure or progress to end-stage renal disease (ESRD) and require dialysis because of light chain cast nephropathy. Kidney failure in patients with presumed multiple myeloma also may result from amyloidosis, light chain deposition disease, or acute tubular necrosis caused by nephrotoxic agents; therefore, identification of patients at risk for kidney damage is essential. The International Myeloma Foundation's Nurse Leadership Board has developed practice recommendations for screening renal function, identifying positive and negative contributing risk and environmental factors, selecting appropriate therapies and supportive care measures to decrease progression to ESRD, and enacting dialysis to reduce and manage renal complications in patients with multiple myeloma.

Myeloma-Derived Light Chain Paired with a Diagnostic Monoclonal Antibody Hinders Immunoassay Performance.

PubMed

Tu, Bailin; Tieman, Bryan; Moore, Jeffrey; Pan, You; Muerhoff, A Scott

2017-06-01

Monoclonal antibodies are widely used as the capture and detection reagents in diagnostic immunoassays. In the past, myeloma fusion partners expressing endogenous heavy and/or light chains were often used to generate hybridoma cell lines. As a result, mixed populations of antibodies were produced that can cause inaccurate test results, poor antibody stability, and significant lot-to-lot variability. We describe one such scenario where the P3U1 (P3X63Ag8U.1) myeloma fusion partner was used in the generation of a hybridoma producing protein induced vitamin K absence/antagonist-II (PIVKA II) antibody. The hybridoma produces three subpopulations of immunoglobulin as determined by ion exchange (IEx) chromatography that exhibit varying degrees of immunoreactivity (0%, 50%, or 100%) to the target antigen as determined by Surface Plasmon Resonance. To produce an antibody with the highest possible sensitivity and specificity, the antigen-specific heavy and light chain variable domains (VH and VL) were cloned from the hybridoma and tethered to murine IgG1 and kappa scaffolds. The resulting recombinant antibody was expressed in Chinese hamster ovary cells and is compatible for use in a diagnostic immunoassay.

Update on treatment of light chain amyloidosis

PubMed Central

Mahmood, Shameem; Palladini, Giovanni; Sanchorawala, Vaishali; Wechalekar, Ashutosh

2014-01-01

Light chain amyloidosis is the most common type of amyloidosis as a consequence of protein misfolding of aggregates composed of amyloid fibrils. The clinical features are dependent on the organs involved, typically cardiac, renal, hepatic, peripheral and autonomic neuropathy and soft tissue. A tissue biopsy or fat aspirate is needed to confirm the presence/type of amyloid and prognostic tools are important in a risk stratified approach to treatment. Autologous stem cell transplant eligibility should be assessed at baseline, weighing the reversible or non-reversible contraindications, toxicity of treatment and chemotherapy alternatives available. Chemotherapy options include melphalan, thalidomide, bortezomib, lenalidomide, bendamustine in combination with dexamethasone. Many studies have explored these treatment modalities, with ongoing debate about the optimal first line and sequential treatment thereafter. Attaining a very good partial response or better is the treatment goal coupled with early assessment central to optimizing treatment. One major challenge remains increasing the awareness of this disease, frequently diagnosed late as the presenting symptoms mimic many other medical conditions. This review focuses on the treatments for light chain amyloidosis, how these treatments have evolved over the years, improved patient risk stratification, toxicities encountered and future directions. PMID:24497558

Two Distantly Spaced Basic Patches in the Flexible Domain of Huntingtin-Interacting Protein 1 (HIP1) Are Essential for the Binding of Clathrin Light Chain.

PubMed

Ybe, Joel A; Clegg, Mary E; Illingworth, Melissa; Gonzalez, Claire; Niu, Qian

2009-01-01

The interaction between HIP family proteins (HIP1 and HIP12/1R) and clathrin is fundamental to endocytosis. We used circular dichroism (CD) to study the stability of an HIP1 subfragment (aa468-530) that is splayed open. CD thermal melts show HIP1 468-530 is only stable at low temperatures, but this HIP1 fragment contains a structural unit that does not melt out even at 83°C. We then created HIP1 mutants to probe our hypothesis that a short hydrophobic path in the opened region is the binding site for clathrin light chain. We found that the binding of hub/LCb was sensitive to mutating two distantly separated basic residues (K474 and K494). The basic patches marked by K474 and K494 are conserved in HIP12/1R. The lack of conservation in sla2p (S. cerevisiae), HIP1 from D. melanogaster, and HIP1 homolog ZK370.3 from C. elegans implies the binding of HIP1 and HIP1 homologs to clathrin light chain may be different in these organisms.

Two Distantly Spaced Basic Patches in the Flexible Domain of Huntingtin-Interacting Protein 1 (HIP1) Are Essential for the Binding of Clathrin Light Chain

PubMed Central

Ybe, Joel A.; Clegg, Mary E.; Illingworth, Melissa; Gonzalez, Claire; Niu, Qian

2009-01-01

The interaction between HIP family proteins (HIP1 and HIP12/1R) and clathrin is fundamental to endocytosis. We used circular dichroism (CD) to study the stability of an HIP1 subfragment (aa468-530) that is splayed open. CD thermal melts show HIP1 468-530 is only stable at low temperatures, but this HIP1 fragment contains a structural unit that does not melt out even at 83°C. We then created HIP1 mutants to probe our hypothesis that a short hydrophobic path in the opened region is the binding site for clathrin light chain. We found that the binding of hub/LCb was sensitive to mutating two distantly separated basic residues (K474 and K494). The basic patches marked by K474 and K494 are conserved in HIP12/1R. The lack of conservation in sla2p (S. cerevisiae), HIP1 from D. melanogaster, and HIP1 homolog ZK370.3 from C. elegans implies the binding of HIP1 and HIP1 homologs to clathrin light chain may be different in these organisms. PMID:22820750

Adaptive surrogate model based multiobjective optimization for coastal aquifer management

NASA Astrophysics Data System (ADS)

Song, Jian; Yang, Yun; Wu, Jianfeng; Wu, Jichun; Sun, Xiaomin; Lin, Jin

2018-06-01

In this study, a novel surrogate model assisted multiobjective memetic algorithm (SMOMA) is developed for optimal pumping strategies of large-scale coastal groundwater problems. The proposed SMOMA integrates an efficient data-driven surrogate model with an improved non-dominated sorted genetic algorithm-II (NSGAII) that employs a local search operator to accelerate its convergence in optimization. The surrogate model based on Kernel Extreme Learning Machine (KELM) is developed and evaluated as an approximate simulator to generate the patterns of regional groundwater flow and salinity levels in coastal aquifers for reducing huge computational burden. The KELM model is adaptively trained during evolutionary search to satisfy desired fidelity level of surrogate so that it inhibits error accumulation of forecasting and results in correctly converging to true Pareto-optimal front. The proposed methodology is then applied to a large-scale coastal aquifer management in Baldwin County, Alabama. Objectives of minimizing the saltwater mass increase and maximizing the total pumping rate in the coastal aquifers are considered. The optimal solutions achieved by the proposed adaptive surrogate model are compared against those solutions obtained from one-shot surrogate model and original simulation model. The adaptive surrogate model does not only improve the prediction accuracy of Pareto-optimal solutions compared with those by the one-shot surrogate model, but also maintains the equivalent quality of Pareto-optimal solutions compared with those by NSGAII coupled with original simulation model, while retaining the advantage of surrogate models in reducing computational burden up to 94% of time-saving. This study shows that the proposed methodology is a computationally efficient and promising tool for multiobjective optimizations of coastal aquifer managements.

Surrogate motherhood as a medical treatment procedure for women's infertility.

PubMed

Jovic, Olga S

2011-03-01

The content of this work is conceived on the research of the consequences of surrogate motherhood as a process of assisted procreation, which represent a way of parenthood in cases when it is not possible to realize parenthood through a natural way. Surrogate motherhood is a process in which a woman (surrogate mother) agrees to carry a pregnancy with the intent to give the child to the couple with whom she has made a contract on surrogate maternity after the birth. This process of conception and birth makes the determination of the child's origin on its mother's side hard to determine, because of the distinction of the genetic and gestation phases of the two women. The concept of surrogate motherhood is to appear in two forms, depending on the existence or the non-existence of the genetic link between the surrogate mother and the child she gives birth to. There are gestation (full) and genetic (partial) surrogates each with different modalities and legal and ethical implications. In Serbia, Infertility Treatment and the Bio-medically Assisted Procreation Act from 2009 explicitly forbids surrogate motherhood, despite the fact that an infertile couple decides to use it, as a rule, after having tried all other treatment procedures, in cases when there is a diagnosis but the conventional treatment applied has not produced the desired results. Given the fact that no one has the right to ignore the sufferings of people who cannot procreate naturally, the medical practice and legal science in our country plead for a formulation of a legal framework in which to apply surrogate motherhood as an infertility treatment, under particular conditions.

Advance Care Planning Beyond Advance Directives: Perspectives from Patients and Surrogates

PubMed Central

McMahan, Ryan; Knight, Sara J.; Fried, Terri R.; Sudore, Rebecca L.

2014-01-01

Context Advance care planning (ACP) has focused on documenting life-sustaining treatment preferences in advance directives (ADs). ADs alone may be insufficient to prepare diverse patients and surrogates for complex medical decisions. Objectives To understand what steps best prepare patients and surrogates for decision making. Methods We conducted 13 English/Spanish focus groups with participants from a Veterans Affairs and county hospital and the community. Seven groups included patients (n=38) aged ≥65 years, who reported making serious medical decisions. Six separate groups included surrogates (n=31), aged ≥18 years, who made decisions for others. Semi-structured focus groups asked what activities best prepared participants for decision making. Two investigators independently coded data and performed thematic content analysis. Disputes were resolved by consensus. Results Mean±SD patient age was 78±8 years and 61% were non-white. Mean±SD surrogate age was 57±10 years and 91% were non-white. Qualitative analysis identified four overarching themes about how to best prepare for decision making: 1) identify values based on past experiences and quality of life, 2) choose surrogates wisely and verify they understand their role, 3) decide whether to grant leeway in surrogate decision making, and 4) inform other family and friends of one's wishes to prevent conflict. Conclusion Beyond ADs, patients and surrogates recommend several additional steps to prepare for medical decision making including using past experiences to identify values, verifying the surrogate understands their role, deciding whether to grant surrogates leeway, and informing other family and friends of one's wishes. Future ACP interventions should consider incorporating these additional ACP activities. PMID:23200188

Multiscale registration algorithm for alignment of meshes

NASA Astrophysics Data System (ADS)

Vadde, Srikanth; Kamarthi, Sagar V.; Gupta, Surendra M.

2004-03-01

Taking a multi-resolution approach, this research work proposes an effective algorithm for aligning a pair of scans obtained by scanning an object's surface from two adjacent views. This algorithm first encases each scan in the pair with an array of cubes of equal and fixed size. For each scan in the pair a surrogate scan is created by the centroids of the cubes that encase the scan. The Gaussian curvatures of points across the surrogate scan pair are compared to find the surrogate corresponding points. If the difference between the Gaussian curvatures of any two points on the surrogate scan pair is less than a predetermined threshold, then those two points are accepted as a pair of surrogate corresponding points. The rotation and translation values between the surrogate scan pair are determined by using a set of surrogate corresponding points. Using the same rotation and translation values the original scan pairs are aligned. The resulting registration (or alignment) error is computed to check the accuracy of the scan alignment. When the registration error becomes acceptably small, the algorithm is terminated. Otherwise the above process is continued with cubes of smaller and smaller sizes until the algorithm is terminated. However at each finer resolution the search space for finding the surrogate corresponding points is restricted to the regions in the neighborhood of the surrogate points that were at found at the preceding coarser level. The surrogate corresponding points, as the resolution becomes finer and finer, converge to the true corresponding points on the original scans. This approach offers three main benefits: it improves the chances of finding the true corresponding points on the scans, minimize the adverse effects of noise in the scans, and reduce the computational load for finding the corresponding points.

DEATH-STAR: Silicon and photovoltaic fission fragment detector arrays for light-ion induced fission correlation studies

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

Koglin, J. D.; Burke, J. T.; Fisher, S. E.

Here, the Direct Excitation Angular Tracking pHotovoltaic-Silicon Telescope ARray (DEATH-STAR) combines a series of 12 silicon detectors in a ΔE–E configuration for charged particle identification with a large-area array of 56 photovoltaic (solar) cells for detection of fission fragments. The combination of many scattering angles and fission fragment detectors allows for an angular-resolved tool to study reaction cross sections using the surrogate method, anisotropic fission distributions, and angular momentum transfers through stripping, transfer, inelastic scattering, and other direct nuclear reactions. The unique photovoltaic detectors efficiently detect fission fragments while being insensitive to light ions and have a timing resolution ofmore » 15.63±0.37 ns. Alpha particles are detected with a resolution of 35.5 keV 1σ at 7.9 MeV. Measured fission fragment angular distributions are also presented.« less

DEATH-STAR: Silicon and Photovoltaic Fission Fragment Detector Arrays for Light-Ion Induced Fission Correlation Studies

NASA Astrophysics Data System (ADS)

Koglin, J. D.; Burke, J. T.; Fisher, S. E.; Jovanovic, I.

2017-05-01

The Direct Excitation Angular Tracking pHotovoltaic-Silicon Telescope ARray (DEATH-STAR) combines a series of 12 silicon detectors in a ΔE - E configuration for charged particle identification with a large-area array of 56 photovoltaic (solar) cells for detection of fission fragments. The combination of many scattering angles and fission fragment detectors allows for an angular-resolved tool to study reaction cross sections using the surrogate method, anisotropic fission distributions, and angular momentum transfers through stripping, transfer, inelastic scattering, and other direct nuclear reactions. The unique photovoltaic detectors efficiently detect fission fragments while being insensitive to light ions and have a timing resolution of 15.63±0.37 ns. Alpha particles are detected with a resolution of 35.5 keV 1σ at 7.9 MeV. Measured fission fragment angular distributions are also presented.

DEATH-STAR: Silicon and photovoltaic fission fragment detector arrays for light-ion induced fission correlation studies

DOE PAGES

Koglin, J. D.; Burke, J. T.; Fisher, S. E.; ...

2017-02-20

Here, the Direct Excitation Angular Tracking pHotovoltaic-Silicon Telescope ARray (DEATH-STAR) combines a series of 12 silicon detectors in a ΔE–E configuration for charged particle identification with a large-area array of 56 photovoltaic (solar) cells for detection of fission fragments. The combination of many scattering angles and fission fragment detectors allows for an angular-resolved tool to study reaction cross sections using the surrogate method, anisotropic fission distributions, and angular momentum transfers through stripping, transfer, inelastic scattering, and other direct nuclear reactions. The unique photovoltaic detectors efficiently detect fission fragments while being insensitive to light ions and have a timing resolution ofmore » 15.63±0.37 ns. Alpha particles are detected with a resolution of 35.5 keV 1σ at 7.9 MeV. Measured fission fragment angular distributions are also presented.« less

Softening of the stiffness of bottle-brush polymers by mutual interaction

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

Bolisetty, S.; Airaud, C.; Rosenfeldt, S.

2007-04-15

We study bottle-brush macromolecules in a good solvent by small-angle neutron scattering (SANS), static light scattering (SLS), and dynamic light scattering (DLS). These polymers consist of a linear backbone to which long side chains are chemically grafted. The backbone contains about 1600 monomer units (weight average) and every second monomer unit carries side chains with approximately 60 monomer units. The SLS and SANS data extrapolated to infinite dilution lead to the form factor of the polymer that can be described in terms of a wormlike chain with a contour length of 380 nm and a persistence length of 17.5 nm.more » An analysis of the DLS data confirms these model parameters. The scattering intensities taken at finite concentration can be modeled using the polymer reference interaction site model. It reveals a softening of the bottle-brush polymers caused by their mutual interaction. We demonstrate that the persistence decreases from 17.5 nm down to 5 nm upon increasing the concentration from dilute solution to the highest concentration (40.59 g/l) under consideration. The observed softening of the chains is comparable to the theoretically predicted decrease of the electrostatic persistence length of linear polyelectrolyte chains at finite concentrations.« less

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

Mueller, Charles J.; Cannella, William J.; Bays, J. Timothy

The primary objectives of this work were to formulate, blend, and characterize a set of four ultralow-sulfur diesel surrogate fuels in quantities sufficient to enable their study in single-cylinder-engine and combustion-vessel experiments. The surrogate fuels feature increasing levels of compositional accuracy (i.e., increasing exactness in matching hydrocarbon structural characteristics) relative to the single target diesel fuel upon which the surrogate fuels are based. This approach was taken to assist in determining the minimum level of surrogate-fuel compositional accuracy that is required to adequately emulate the performance characteristics of the target fuel under different combustion modes. For each of the fourmore » surrogate fuels, an approximately 30 L batch was blended, and a number of the physical and chemical properties were measured. In conclusion, this work documents the surrogate-fuel creation process and the results of the property measurements.« less

Ethical Concerns and Procedural Pathways for Patients Who are Incapacitated and Alone: Implications from a Qualitative Study for Advancing Ethical Practice

PubMed Central

Catlin, Casey; Kwak, Jennifer; Wood, Erica; Teaster, Pamela B.

2017-01-01

Adults who are incapacitated and alone, having no surrogates, may be known as “unbefriended.” Decision-making for these particularly vulnerable patients is a common and vexing concern for healthcare providers and hospital ethics committees. When all other avenues for resolving the need for surrogate decision-making fail, patients who are incapacitated and alone may be referred for “public guardianship” or guardianship of last resort. While an appropriate mechanism in theory, these programs are often under-staffed and under-funded, laying the consequences of inadequacies on the healthcare system and the patient him or herself. We describe a qualitative study of professionals spanning clinical, court, and agency settings about the mechanisms for resolving surrogate consent for these patients and problems therein within the state of Massachusetts. Interviews found that all participants encountered adults who are incapacitated and without surrogates. Four approaches for addressing surrogate needs were: (1) work to restore capacity; (2) find previously unknown surrogates; (3) work with agencies to obtain surrogates; and (4) access the guardianship system. The use of guardianship was associated with procedural challenges and ethical concerns including delays in care, short term gains for long term costs, inabilities to meet a patient’s values and preferences, conflicts of interest, and ethical discomfort among interviewees. Findings are discussed in the context of resources to restore capacity, identify previously unknown surrogates, and establish improved surrogate mechanisms for this vulnerable population. PMID:28084575

Ethical Concerns and Procedural Pathways for Patients Who are Incapacitated and Alone: Implications from a Qualitative Study for Advancing Ethical Practice.

PubMed

Moye, Jennifer; Catlin, Casey; Kwak, Jennifer; Wood, Erica; Teaster, Pamela B

2017-06-01

Adults who are incapacitated and alone, having no surrogates, may be known as "unbefriended." Decision-making for these particularly vulnerable patients is a common and vexing concern for healthcare providers and hospital ethics committees. When all other avenues for resolving the need for surrogate decision-making fail, patients who are incapacitated and alone may be referred for "public guardianship" or guardianship of last resort. While an appropriate mechanism in theory, these programs are often under-staffed and under-funded, laying the consequences of inadequacies on the healthcare system and the patient him or herself. We describe a qualitative study of professionals spanning clinical, court, and agency settings about the mechanisms for resolving surrogate consent for these patients and problems therein within the state of Massachusetts. Interviews found that all participants encountered adults who are incapacitated and without surrogates. Four approaches for addressing surrogate needs were: (1) work to restore capacity; (2) find previously unknown surrogates; (3) work with agencies to obtain surrogates; and (4) access the guardianship system. The use of guardianship was associated with procedural challenges and ethical concerns including delays in care, short term gains for long term costs, inabilities to meet a patient's values and preferences, conflicts of interest, and ethical discomfort among interviewees. Findings are discussed in the context of resources to restore capacity, identify previously unknown surrogates, and establish improved surrogate mechanisms for this vulnerable population.

Metallocene-Containing Homopolymers and Heterobimetallic Block Copolymers via Photoinduced RAFT Polymerization

PubMed Central

Yang, Peng; Pageni, Parasmani; Kabir, Mohammad Pabel; Zhu, Tianyu; Tang, Chuanbing

2017-01-01

We report the synthesis of cationic cobaltocenium and neutral ferrocene containing homopolymers mediated by photoinduced reversible addition-fragmentation chain transfer (RAFT) polymerization with a photocatalyst fac-[Ir(ppy)3]. The homopolymers were further used as macromolecular chain transfer agents to synthesize diblock copolymers via chain extension. Controlled/“living” feature of photoinduced RAFT polymerization was confirmed by kinetic studies even without prior deoxygenation. A light switch between ON and OFF provided a spatiotemporal control of polymerization. PMID:29276651

Surrogate immiscible liquid pairs with refractive indexes matchable over a wide range of density and viscosity ratios

NASA Astrophysics Data System (ADS)

Saksena, Rajat; Christensen, Kenneth T.; Pearlstein, Arne J.

2015-08-01

In liquid-liquid flows, use of optical diagnostics is limited by interphase refractive index mismatch, which leads to optical distortion and complicates data interpretation, and sometimes also by opacity. Both problems can be eliminated using a surrogate pair of immiscible index-matched transparent liquids, whose density and viscosity ratios match corresponding ratios for the original liquid pair. We show that a wide range of density and viscosity ratios is accessible using aqueous solutions of 1,2-propanediol and CsBr (for which index, density, and viscosity are available), and solutions of light and heavy silicone oils and 1-bromooctane (for which we measured the same properties at 119 compositions). For each liquid phase, polynomials in the composition variables, least-squares fitted to index and density and to the logarithm of kinematic viscosity, were used to determine accessible density and viscosity ratios for each matchable index. Index-matched solution pairs can be prepared with density and viscosity ratios equal to those for water-liquid CO2 at 0 °C over a range of pressure (allowing water-liquid CO2 behavior at inconveniently high pressure to be simulated by 1-bar experiments), and for water-crude oil and water-trichloroethylene (avoiding opacity and toxicity problems, respectively), each over a range of temperature. For representative index-matched solutions, equilibration changes index, density, and viscosity only slightly, and mass spectrometry and elemental analysis show that no component of either phase has significant interphase solubility. Finally, procedures are described for iteratively reducing the residual index mismatch in surrogate solution pairs prepared on the basis of approximate polynomial fits to experimental data, and for systematically dealing with nonzero interphase solubility.

Modeling Water Clarity and Light Quality in Oceans

EPA Science Inventory

Phytoplankton is a primary producer of organic compounds, and it forms the base of the food chain in ocean waters. The concentration of phytoplankton in the water column controls water clarity and the amount and quality of light that penetrates through it. The availability of ade...

Involvement of all-trans-retinal in acute light-induced retinopathy of mice.

PubMed

Maeda, Akiko; Maeda, Tadao; Golczak, Marcin; Chou, Steven; Desai, Amar; Hoppel, Charles L; Matsuyama, Shigemi; Palczewski, Krzysztof

2009-05-29

Exposure to bright light can cause visual dysfunction and retinal photoreceptor damage in humans and experimental animals, but the mechanism(s) remain unclear. We investigated whether the retinoid cycle (i.e. the series of biochemical reactions required for vision through continuous generation of 11-cis-retinal and clearance of all-trans-retinal, respectively) might be involved. Previously, we reported that mice lacking two enzymes responsible for clearing all-trans-retinal, namely photoreceptor-specific ABCA4 (ATP-binding cassette transporter 4) and RDH8 (retinol dehydrogenase 8), manifested retinal abnormalities exacerbated by light and associated with accumulation of diretinoid-pyridinium-ethanolamine (A2E), a condensation product of all-trans-retinal and a surrogate marker for toxic retinoids. Now we show that these mice develop an acute, light-induced retinopathy. However, cross-breeding these animals with lecithin:retinol acyltransferase knock-out mice lacking retinoids within the eye produced progeny that did not exhibit such light-induced retinopathy until gavaged with the artificial chromophore, 9-cis-retinal. No significant ocular accumulation of A2E occurred under these conditions. These results indicate that this acute light-induced retinopathy requires the presence of free all-trans-retinal and not, as generally believed, A2E or other retinoid condensation products. Evidence is presented that the mechanism of toxicity may include plasma membrane permeability and mitochondrial poisoning that lead to caspase activation and mitochondria-associated cell death. These findings further understanding of the mechanisms involved in light-induced retinal degeneration.

21 CFR 601.41 - Approval based on a surrogate endpoint or on an effect on a clinical endpoint other than survival...

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 7 2014-04-01 2014-04-01 false Approval based on a surrogate endpoint or on an... Approval based on a surrogate endpoint or on an effect on a clinical endpoint other than survival or... uncertainty as to the relation of the surrogate endpoint to clinical benefit, or of the observed clinical...

21 CFR 314.510 - Approval based on a surrogate endpoint or on an effect on a clinical endpoint other than survival...

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Approval based on a surrogate endpoint or on an... Serious or Life-Threatening Illnesses § 314.510 Approval based on a surrogate endpoint or on an effect on... the drug product has an effect on a surrogate endpoint that is reasonably likely, based on...

21 CFR 314.510 - Approval based on a surrogate endpoint or on an effect on a clinical endpoint other than survival...

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 5 2014-04-01 2014-04-01 false Approval based on a surrogate endpoint or on an... Serious or Life-Threatening Illnesses § 314.510 Approval based on a surrogate endpoint or on an effect on... the drug product has an effect on a surrogate endpoint that is reasonably likely, based on...