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Sample records for anti-malarial drug sensitivity

  1. Co-treatment with the anti-malarial drugs mefloquine and primaquine highly sensitizes drug-resistant cancer cells by increasing P-gp inhibition.

    PubMed

    Kim, Ju-Hwa; Choi, Ae-Ran; Kim, Yong Kee; Yoon, Sungpil

    2013-11-22

    The purpose of this study was to identify conditions that will increase the sensitivity of resistant cancer cells to anti-mitotic drugs. Currently, atovaquine (ATO), chloroquine (CHL), primaquine (PRI), mefloquine (MEF), artesunate (ART), and doxycycline (DOY) are the most commonly used anti-malarial drugs. Herein, we tested whether anti-malarial drugs can sensitize drug-resistant KBV20C cancer cells. None of the six tested anti-malarial drugs was found to better sensitize the drug-resistant cells compared to the sensitive KB cells. With an exception of DOY, all other anti-malarial drugs tested could sensitize both KB and KBV20C cells to a similar extent, suggesting that anti-malarial drugs could be used for sensitive as well as resistant cancer cells. Furthermore, we examined the effects of anti-malarial drugs in combination with an antimitotic drug, vinblastine (VIN) on the sensitisation of resistant KBV20C cells. Using viability assay, microscopic observation, assessment of cleaved PARP, and Hoechst staining, we identified that two anti-malarial drugs, PRI and MEF, highly sensitized KBV20C-resistant cells to VIN treatment. Moreover, PRI- or MEF-induced sensitisation was not observed in VIN-treated sensitive KB parent cells, suggesting that the observed effect is specific to resistant cancer cells. We demonstrated that the PRI and MEF sensitisation mechanism mainly depends on the inhibition of p-glycoprotein (P-gp). Our findings may contribute to the development of anti-malarial drug-based combination therapies for patients resistant to anti-mitotic drugs.

  2. Anti-malarial Drug Design by Targeting Apicoplasts: New Perspectives

    PubMed Central

    Mukherjee, Avinaba; Sadhukhan, Gobinda Chandra

    2016-01-01

    Objectives: Malaria has been a major global health problem in recent times with increasing mortality. Current treatment methods include parasiticidal drugs and vaccinations. However, resistance among malarial parasites to the existing drugs has emerged as a significant area of concern in anti-malarial drug design. Researchers are now desperately looking for new targets to develop anti-malarials drug which is more target specific. Malarial parasites harbor a plastid-like organelle known as the ‘apicoplast’, which is thought to provide an exciting new outlook for the development of drugs to be used against the parasite. This review elaborates on the current state of development of novel compounds targeted againstemerging malaria parasites. Methods: The apicoplast, originates by an endosymbiotic process, contains a range of metabolic pathways and housekeeping processes that differ from the host body and thereby presents ideal strategies for anti-malarial drug therapy. Drugs are designed by targeting the unique mechanism of the apicoplasts genetic machinery. Several anabolic and catabolic processes, like fatty acid, isopenetyl diphosphate and heme synthess in this organelle, have also been targeted by drugs. Results: Apicoplasts offer exciting opportunities for the development of malarial treatment specific drugs have been found to act by disrupting this organelle’s function, which wouldimpede the survival of the parasite. Conclusion: Recent advanced drugs, their modes of action, and their advantages in the treatment of malaria by using apicoplasts as a target are discussed in this review which thought to be very useful in desigining anti-malarial drugs. Targetting the genetic machinery of apicoplast shows a great advantange regarding anti-malarial drug design. Critical knowledge of these new drugs would give a healthier understanding for deciphering the mechanism of action of anti-malarial drugs when targeting apicoplasts to overcome drug resistance. PMID

  3. Inclusion of gametocyte parameters in anti-malarial drug efficacy studies: filling a neglected gap needed for malaria elimination.

    PubMed

    Abdul-Ghani, Rashad; Basco, Leonardo K; Beier, John C; Mahdy, Mohammed A K

    2015-10-19

    Standard anti-malarial drug efficacy and drug resistance assessments neglect the gametocyte parameters in their protocols. With the spread of drug resistance and the absence of clinically proven vaccines, the use of gametocytocidal drugs or drug combinations with transmission-blocking activity is a high priority for malaria control and elimination. However, the limited repertoire of gametocytocidal drugs and induction of gametocytogenesis after treatment with certain anti-malarial drugs necessitate both regular monitoring of gametocytocidal activities of anti-malarial drugs in clinical use and the effectiveness of candidate gametocytocidal agents. Therefore, updating current protocols of anti-malarial drug efficacy is needed to reflect the effects of anti-malarial drugs or drug combinations on gametocyte carriage and gametocyte density along with asexual parasite density. Developing protocols of anti-malarial drug efficacy that include gametocyte parameters related to both microscopic and submicroscopic gametocytaemias is important if drugs or drug combinations are to be strategically used in transmission-blocking interventions in the context of malaria elimination. The present piece of opinion highlights the challenges in gametocyte detection and follow-up and discuss the need for including the gametocyte parameter in anti-malarial efficacy studies.

  4. Molecular Farming in Artemisia annua, a Promising Approach to Improve Anti-malarial Drug Production

    PubMed Central

    Pulice, Giuseppe; Pelaz, Soraya; Matías-Hernández, Luis

    2016-01-01

    Malaria is a parasite infection affecting millions of people worldwide. Even though progress has been made in prevention and treatment of the disease; an estimated 214 million cases of malaria occurred in 2015, resulting in 438,000 estimated deaths; most of them occurring in Africa among children under the age of five. This article aims to review the epidemiology, future risk factors and current treatments of malaria, with particular focus on the promising potential of molecular farming that uses metabolic engineering in plants as an effective anti-malarial solution. Malaria represents an example of how a health problem may, on one hand, influence the proper development of a country, due to its burden of the disease. On the other hand, it constitutes an opportunity for lucrative business of diverse stakeholders. In contrast, plant biofarming is proposed here as a sustainable, promising, alternative for the production, not only of natural herbal repellents for malaria prevention but also for the production of sustainable anti-malarial drugs, like artemisinin (AN), used for primary parasite infection treatments. AN, a sesquiterpene lactone, is a natural anti-malarial compound that can be found in Artemisia annua. However, the low concentration of AN in the plant makes this molecule relatively expensive and difficult to produce in order to meet the current worldwide demand of Artemisinin Combination Therapies (ACTs), especially for economically disadvantaged people in developing countries. The biosynthetic pathway of AN, a process that takes place only in glandular secretory trichomes of A. annua, is relatively well elucidated. Significant efforts have been made using plant genetic engineering to increase production of this compound. These include diverse genetic manipulation approaches, such as studies on diverse transcription factors which have been shown to regulate the AN genetic pathway and other biological processes. Results look promising; however, further

  5. CRIMALDDI: a co-ordinated, rational, and integrated effort to set logical priorities in anti-malarial drug discovery initiatives.

    PubMed

    Boulton, Ian C; Nwaka, Solomon; Bathurst, Ian; Lanzer, Michael; Taramelli, Donatella; Vial, Henri; Doerig, Christian; Chibale, Kelly; Ward, Steve A

    2010-07-13

    Despite increasing efforts and support for anti-malarial drug R&D, globally anti-malarial drug discovery and development remains largely uncoordinated and fragmented. The current window of opportunity for large scale funding of R&D into malaria is likely to narrow in the coming decade due to a contraction in available resources caused by the current economic difficulties and new priorities (e.g. climate change). It is, therefore, essential that stakeholders are given well-articulated action plans and priorities to guide judgments on where resources can be best targeted.The CRIMALDDI Consortium (a European Union funded initiative) has been set up to develop, through a process of stakeholder and expert consultations, such priorities and recommendations to address them. It is hoped that the recommendations will help to guide the priorities of the European anti-malarial research as well as the wider global discovery agenda in the coming decade.

  6. The effect of malaria and anti-malarial drugs on skeletal and cardiac muscles.

    PubMed

    Marrelli, Mauro Toledo; Brotto, Marco

    2016-11-02

    Malaria remains one of the most important infectious diseases in the world, being a significant public health problem associated with poverty and it is one of the main obstacles to the economy of an endemic country. Among the several complications, the effects of malaria seem to target the skeletal muscle system, leading to symptoms, such as muscle aches, muscle contractures, muscle fatigue, muscle pain, and muscle weakness. Malaria cause also parasitic coronary artery occlusion. This article reviews the current knowledge regarding the effect of malaria disease and the anti-malarial drugs on skeletal and cardiac muscles. Research articles and case report publications that addressed aspects that are important for understanding the involvement of malaria parasites and anti-malarial therapies affecting skeletal and cardiac muscles were analysed and their findings summarized. Sequestration of red blood cells, increased levels of serum creatine kinase and reduced muscle content of essential contractile proteins are some of the potential biomarkers of the damage levels of skeletal and cardiac muscles. These biomarkers might be useful for prevention of complications and determining the effectiveness of interventions designed to protect cardiac and skeletal muscles from malaria-induced damage.

  7. The biological and clinical activity of anti-malarial drugs in autoimmune disorders.

    PubMed

    Taherian, Elham; Rao, Anshul; Malemud, Charles J; Askari, Ali D

    2013-01-01

    Chloroquine and hydroxychloroquine are 4-aminoquinoline compounds commonly employed as anti-malarial drugs. Chloroquine and its synthetic analogue, hydroxychloroquine also belong to the disease-modifying anti-rheumatic drug class because these drugs are immunosuppressive. The immunosuppressive activity of chloroquine and hydroxychloroquine is likely to account for their capacity to reduce T-cell and B-cell hyperactivity as well as pro-inflammatory cytokine gene expression. This review evaluated experimental and clinical trials results as well as clinical response data relative to the use of chloroquine and/or hydroxychloroquine as first-line medical therapies in systemic lupus erythematosus, rheumatoid arthritis, primary Sjogren's syndrome, the anti-phospholipid syndrome and in the treatment of sarcoidosis. A primary outcomes measure in these clinical trials was the extent to which chloroquine and/or hydroxychloroquine reduced disease progression or exacerbations and/or the use and dosage of corticosteroids. The relative efficacy of chloroquine and hydroxychloroquine in modifying the clinical course of these autoimmune disorders is balanced against evidence that these drugs induce adverse effects which may reduce their use and effectiveness in the therapy of autoimmune disorders.

  8. Repurposing the anti-malarial drug, quinacrine: new anti-colitis properties

    PubMed Central

    Chumanevich, Alexander A.; Witalison, Erin E.; Chaparala, Anusha; Chumanevich, Anastasiya; Nagarkatti, Prakash; Nagarkatti, Mitzi; Hofseth, Lorne J.

    2016-01-01

    Background Ulcerative colitis (UC) is a chronic inflammatory bowel disease that is associated with an increased risk of colorectal cancer in 8-10 years after disease onset. Current colitis treatment strategies do not offer a cure for the disease, but only treat the symptoms with limited success and dangerous side-effects. Also, there is no preventive treatment for either UC or colorectal cancer. Quinacrine is an anti-malarial drug with versatile use in the treatment of diseases involving inflammatory response such as rheumatoid arthritis and lupus erythematosus. It also has putative anti-cancer effect. Quinacrine's anti-inflammatory, anti-oxidant properties, and anti-tumorigenic properties make it a potential small molecule preventive agent for both UC and associated colorectal cancer. Results There were obvious changes in the CDI, histology, and inflammatory load in quinacrine-treated groups in a dose and time dependent manner in both models of UC, induced by chemical or haptenating agent. Methods We tested quinacrine at two different doses as a colitis treatment agent in two mouse models of UC - the dextran sulfate sodium and oxazolone. The clinical disease index (CDI), histological changes of the colon, levels of inflammatory markers (Cox-2, iNOS, p53) and overall health vitals were evaluated. Conclusions We demonstrate that quinacrine successfully suppresses colitis without any indication of toxicity or side-effects in two mouse models of UC. PMID:27447967

  9. Quinine, an old anti-malarial drug in a modern world: role in the treatment of malaria.

    PubMed

    Achan, Jane; Talisuna, Ambrose O; Erhart, Annette; Yeka, Adoke; Tibenderana, James K; Baliraine, Frederick N; Rosenthal, Philip J; D'Alessandro, Umberto

    2011-05-24

    Quinine remains an important anti-malarial drug almost 400 years after its effectiveness was first documented. However, its continued use is challenged by its poor tolerability, poor compliance with complex dosing regimens, and the availability of more efficacious anti-malarial drugs. This article reviews the historical role of quinine, considers its current usage and provides insight into its appropriate future use in the treatment of malaria. In light of recent research findings intravenous artesunate should be the first-line drug for severe malaria, with quinine as an alternative. The role of rectal quinine as pre-referral treatment for severe malaria has not been fully explored, but it remains a promising intervention. In pregnancy, quinine continues to play a critical role in the management of malaria, especially in the first trimester, and it will remain a mainstay of treatment until safer alternatives become available. For uncomplicated malaria, artemisinin-based combination therapy (ACT) offers a better option than quinine though the difficulty of maintaining a steady supply of ACT in resource-limited settings renders the rapid withdrawal of quinine for uncomplicated malaria cases risky. The best approach would be to identify solutions to ACT stock-outs, maintain quinine in case of ACT stock-outs, and evaluate strategies for improving quinine treatment outcomes by combining it with antibiotics. In HIV and TB infected populations, concerns about potential interactions between quinine and antiretroviral and anti-tuberculosis drugs exist, and these will need further research and pharmacovigilance.

  10. Assessment of global reporting of adverse drug reactions for anti-malarials, including artemisinin-based combination therapy, to the WHO Programme for International Drug Monitoring

    PubMed Central

    2011-01-01

    Background In spite of enhanced control efforts, malaria remains a major public health problem causing close to a million deaths annually. With support from several donors, large amounts of artemisinin-based combination therapy (ACT) are being deployed in endemic countries raising safety concerns as little is known about the use of ACT in several of the settings where they are deployed. This project was undertaken to profile the provenance of the pharmacovigilance reporting of all anti-malarials, including ACT to the WHO adverse drug reaction (ADR) database (Vigibase™) over the past 40 years. Methods The WHO Programme for International Drug Monitoring, the Uppsala Monitoring Centre (UMC) provided anonymized extracts of Vigibase™ covering the period 1968-2008. All countries in the programme were clustered according to their malaria control phase and income status. The number of individual case safety reports (ICSRs) of anti-malarials was analyzed according to those clusters. Results From 1968 to 2008, 21,312 ICSRs suspecting anti-malarials were received from 64 countries. Low-income countries, that are also malaria-endemic (categorized as priority 1 countries) submitted only 1.2% of the ICSRs. Only 60 out of 21,312 ICSRs were related to ACT, 51 of which were coming from four sub-Saharan African countries. Although very few ICSRs involved artemisinin-based compounds, many of the adverse events reported were potentially serious. Conclusions This paper illustrates the low reporting of ADRs to anti-malarials in general and ACT in particular. Most reports were submitted by non-endemic and/or high-income countries. Given the current mix of large donor funding, the insufficient information on safety of these drugs, increasing availability of ACT and artemisinin-based monotherapies in public and private sector channels, associated potential for inappropriate use and finally a pipeline of more than 10 new novel anti-malarials in various stages of development, the

  11. Recent progress in the development of anti-malarial quinolones.

    PubMed

    Beteck, Richard M; Smit, Frans J; Haynes, Richard K; N'Da, David D

    2014-08-30

    Available anti-malarial tools have over the ten-year period prior to 2012 dramatically reduced the number of fatalities due to malaria from one million to less than six-hundred and thirty thousand. Although fewer people now die from malaria, emerging resistance to the first-line anti-malarial drugs, namely artemisinins in combination with quinolines and arylmethanols, necessitates the urgent development of new anti-malarial drugs to curb the disease. The quinolones are a promising class of compounds, with some demonstrating potent in vitro activity against the malaria parasite. This review summarizes the progress made in the development of potential anti-malarial quinolones since 2008. The efficacy of these compounds against both asexual blood stages and other stages of the malaria parasite, the nature of putative targets, and a comparison of these properties with anti-malarial drugs currently in clinical use, are discussed.

  12. Malaria Related Perceptions, Care Seeking after Onset of Fever and Anti-Malarial Drug Use in Malaria Endemic Settings of Southwest Ethiopia

    PubMed Central

    Birhanu, Zewdie; Abebe, Lakew; Sudhakar, Morankar; Dissanayake, Gunawardena; Yihdego, Yemane Ye-ebiyo; Alemayehu, Guda; Yewhalaw, Delenasaw

    2016-01-01

    Background Prompt care seeking and appropriate use of anti-malarial drugs are critical components of malaria prevention and control. This study assessed malaria related perceptions, care seeking behavior and anti-malarial drug use in malaria endemic settings of Ethiopia. Methods Data were generated from a community based cross-sectional study conducted among 798 households during January 2014 as part of a larger household behavioral study in three malaria endemic districts of Jimma Zone, Southwest Ethiopia. Both quantitative and qualitative data were collected and analyzed using SPSS 17.0 and STATA 12.0. Results In this study, only 76.1% of the respondents associated malaria to mosquito bite, and incorrect beliefs and perceptions were noted. Despite moderate level of knowledge (estimated mean = 62.2, Std Err = 0.7, 95% CI: 60.6–63.8%), quite high favorable attitude (overall estimated mean = 91.5, Std Err = 0.6, 95% CI: 90.1–92.9%) were recorded towards malaria preventive measures. The mean attitude score for prompt care seeking, appropriate use of anti-malarial drugs, LLIN use and Indoor Residual Spray acceptance was 98.5 (Std Err = 0.4, 95% CI:97.5–99.4), 92.7 (Std Err = 0.6 95% CI:91.5–93.9), 88.8 (Std Err = 0.5, 95% CI:85.5–92.1) and 86.5 (Std Err = 1.2, 95% CI: 83.9–89.1), respectively. The prevalence of fever was 2.9% (116/4107) and of the study participants with fever, 71.9% (95% CI: 65.5–78.3%) sought care and all of them consulted formal health care system. However, only 17 (19.8%) sought care within 24 hours after onset of fever. The frequency of care seeking was higher (77.8%, n = 21/27) and more prompt (28.6%, 6/21) for children under five as compared to old age groups despite it was not statistically significant (p > 0.05). However, higher median time of seeking first care was observed among Muslims and people who did not attend school (p < 0.05). Of those who used anti-malarial drugs, 9.1% indicated that they used it inappropriately

  13. Plasmodial sugar transporters as anti-malarial drug targets and comparisons with other protozoa

    PubMed Central

    2011-01-01

    Glucose is the primary source of energy and a key substrate for most cells. Inhibition of cellular glucose uptake (the first step in its utilization) has, therefore, received attention as a potential therapeutic strategy to treat various unrelated diseases including malaria and cancers. For malaria, blood forms of parasites rely almost entirely on glycolysis for energy production and, without energy stores, they are dependent on the constant uptake of glucose. Plasmodium falciparum is the most dangerous human malarial parasite and its hexose transporter has been identified as being the major glucose transporter. In this review, recent progress regarding the validation and development of the P. falciparum hexose transporter as a drug target is described, highlighting the importance of robust target validation through both chemical and genetic methods. Therapeutic targeting potential of hexose transporters of other protozoan pathogens is also reviewed and discussed. PMID:21676209

  14. Use of the atmospheric generators for capnophilic bacteria Genbag-CO2 for the evaluation of in vitro Plasmodium falciparum susceptibility to standard anti-malarial drugs

    PubMed Central

    2011-01-01

    Background The aim of this study was to evaluate the cultivation system in which the proper atmospheric conditions for growing Plasmodium falciparum parasites were maintained in a sealed bag. The Genbag® system associated with the atmospheric generators for capnophilic bacteria Genbag CO2® was used for in vitro susceptibility test of nine standard anti-malarial drugs and compared to standard incubator conditions. Methods The susceptibility of 36 pre-identified parasite strains from a wide panel of countries was assessed for nine standard anti-malarial drugs (chloroquine, quinine, mefloquine, monodesethylamodiaquine, lumefantrine, dihydroartemisinin, atovaquone and pyrimethamine) by the standard 42-hour 3H-hypoxanthine uptake inhibition method using the Genbag CO2® system and compared to controlled incubator conditions (5% CO2 and 10% O2). Results The counts per minute values in the control wells in incubator atmospheric conditions (5% CO2 and 10% O2) were significantly higher than those of Genbag® conditions (2738 cpm vs 2282 cpm, p < 0.0001). The geometric mean IC50 estimated under the incubator atmospheric conditions was significantly lower for atovaquone (1.2 vs 2.1 nM, p = 0.0011) and higher for the quinolines: chloroquine (127 vs 94 nM, p < 0.0001), quinine (580 vs 439 nM, p < 0.0001), monodesethylamodiaquine (41.4 vs 31.8 nM, p < 0.0001), mefloquine (57.5 vs 49.7 nM, p = 0.0011) and lumefantrine (23.8 vs 21.2 nM, p = 0.0044). There was no significant difference of IC50 between the 2 conditions for dihydroartemisinin, doxycycline and pyrimethamine. To reduce this difference in term of anti-malarial susceptibility, a specific cut-off was estimated for each drug under Genbag® conditions by regression. The cut-off was estimated at 77 nM for chloroquine (vs 100 nM in 10% O2), 611 nM for quinine (vs 800 nM), 30 nM for mefloquine (vs 30 nM), 61 nM for monodesethylamodiaquine (vs 80 nM) and 1729 nM for pyrimethamine (vs 2000 nM). Conclusions The atmospheric

  15. Susceptibility of human Plasmodium knowlesi infections to anti-malarials

    PubMed Central

    2013-01-01

    Background Evidence suggests that Plasmodium knowlesi malaria in Sarawak, Malaysian Borneo remains zoonotic, meaning anti-malarial drug resistance is unlikely to have developed in the absence of drug selection pressure. Therefore, adequate response to available anti-malarial treatments is assumed. Methods Here the ex vivo sensitivity of human P. knowlesi isolates in Malaysian Borneo were studied, using a WHO schizont maturation assay modified to accommodate the quotidian life cycle of this parasite. The in vitro sensitivities of P. knowlesi H strain adapted from a primate infection to in vitro culture (by measuring the production of Plasmodium lactate dehydrogenase) were also examined together with some assays using Plasmodium falciparum and Plasmodium vivax. Results Plasmodium knowlesi is uniformly highly sensitive to artemisinins, variably and moderately sensitive to chloroquine, and less sensitive to mefloquine. Conclusions Taken together with reports of clinical failures when P. knowlesi is treated with mefloquine, the data suggest that caution is required if using mefloquine in prevention or treatment of P. knowlesi infections, until further studies are undertaken. PMID:24245918

  16. Induction of multiple pleiotropic drug resistance genes in yeast engineered to produce an increased level of anti-malarial drug precursor, artemisinic acid

    PubMed Central

    Ro, Dae-Kyun; Ouellet, Mario; Paradise, Eric M; Burd, Helcio; Eng, Diana; Paddon, Chris J; Newman, Jack D; Keasling, Jay D

    2008-01-01

    Background Due to the global occurrence of multi-drug-resistant malarial parasites (Plasmodium falciparum), the anti-malarial drug most effective against malaria is artemisinin, a natural product (sesquiterpene lactone endoperoxide) extracted from sweet wormwood (Artemisia annua). However, artemisinin is in short supply and unaffordable to most malaria patients. Artemisinin can be semi-synthesized from its precursor artemisinic acid, which can be synthesized from simple sugars using microorganisms genetically engineered with genes from A. annua. In order to develop an industrially competent yeast strain, detailed analyses of microbial physiology and development of gene expression strategies are required. Results Three plant genes coding for amorphadiene synthase, amorphadiene oxidase (AMO or CYP71AV1), and cytochrome P450 reductase, which in concert divert carbon flux from farnesyl diphosphate to artemisinic acid, were expressed from a single plasmid. The artemisinic acid production in the engineered yeast reached 250 μg mL-1 in shake-flask cultures and 1 g L-1 in bio-reactors with the use of Leu2d selection marker and appropriate medium formulation. When plasmid stability was measured, the yeast strain synthesizing amorphadiene alone maintained the plasmid in 84% of the cells, whereas the yeast strain synthesizing artemisinic acid showed poor plasmid stability. Inactivation of AMO by a point-mutation restored the high plasmid stability, indicating that the low plasmid stability is not caused by production of the AMO protein but by artemisinic acid synthesis or accumulation. Semi-quantitative reverse-transcriptase (RT)-PCR and quantitative real time-PCR consistently showed that pleiotropic drug resistance (PDR) genes, belonging to the family of ATP-Binding Cassette (ABC) transporter, were massively induced in the yeast strain producing artemisinic acid, relative to the yeast strain producing the hydrocarbon amorphadiene alone. Global transcriptional analysis by

  17. Repurposing the anti-malarial drug dihydroartemisinin suppresses metastasis of non-small-cell lung cancer via inhibiting NF-κB/GLUT1 axis

    PubMed Central

    Jiang, Jie; Geng, Guojun; Yu, Xiuyi; Liu, Hongming; Gao, Jing; An, Hanxiang; Cai, Chengfu; Li, Ning; Shen, Dongyan; Wu, Xiaoqiang; Zheng, Lisheng; Mi, Yanjun; Yang, Shuyu

    2016-01-01

    Non-small-cell lung cancer (NSCLC) is an aggressive malignancy and long-term survival remains unsatisfactory for patients with metastatic and recurrent disease. Repurposing the anti-malarial drug dihydroartemisinin (DHA) has been proved to possess potent antitumor effect on various cancers. However, the effects of DHA in preventing the invasion of NSCLC cells have not been studied. In the present study, we determined the inhibitory effects of DHA on invasion and migration and the possible mechanisms involved using A549 and H1975 cells. DHA inhibited in vitro migration and invasion of NSCLC cells even in low concentration with little cytotoxicity. Additionally, low concentration DHA also inhibited Warburg effect in NSCLC cells. Mechanically, DHA negatively regulates NF-κB signaling to inhibit the GLUT1 translocation. Blocking the NF-κB signaling largely abolishes the inhibitory effects of DHA on the translocation of GLUT1 to the plasma membrane and the Warburg effect. Furthermore, GLUT1 knockdown significantly decreased the inhibition of invasion, and migration by DHA. Our results suggested that DHA can inhibit metastasis of NSCLC by targeting glucose metabolism via inhibiting NF-κB signaling pathway and DHA may deserve further investigation in NSCLC treatment. PMID:27895313

  18. Slowing down glioblastoma progression in mice by running or the anti-malarial drug dihydroartemisinin? Induction of oxidative stress in murine glioblastoma therapy

    PubMed Central

    Lemke, Dieter; Pledl, Hans-Werner; Zorn, Markus; Jugold, Manfred; Green, Ed; Blaes, Jonas; Löw, Sarah; Hertenstein, Anne; Ott, Martina; Sahm, Felix; Steffen, Ann-Catherine; Weiler, Markus; Winkler, Frank; Platten, Michael

    2016-01-01

    Influencing cancer metabolism by lifestyle changes is an attractive strategy as - if effective - exercise-induced problems may be less severe than those induced by classical anti-cancer therapies. Pursuing this idea, clinical trials evaluated the benefit of e.g. different diets such as the ketogenic diet, intermittent caloric restriction and physical exercise (PE) in the primary and secondary prevention of different cancer types. PE proved to be beneficial in the context of breast and colon cancer. Glioblastoma has a dismal prognosis, with an average overall survival of about one year despite maximal safe resection, concomitant radiochemotherapy with temozolomide followed by adjuvant temozolomide therapy. Here, we focused on the influence of PE as an isolated and adjuvant treatment in murine GB therapy. PE did not reduce toxic side effects of chemotherapy in mice administered in a dose escalating scheme as shown before for starvation. Although regular treadmill training on its own had no obvious beneficial effects, its combination with temozolomide was beneficial in the treatment of glioblastoma-bearing mice. As PE might partly act through the induction of reactive oxygen species, dihydroartemisinin - an approved anti-malarial drug which induces oxidative stress in glioma cells - was further evaluated in vitro and in vivo. Dihydroartemisinin showed anti-glioma activity by promoting autophagy, reduced the clonogenic survival and proliferation capacity of glioma cells, and prolonged the survival of tumor bearing mice. Using the reactive oxygen species scavenger n-acetyl-cysteine these effects were in part reversible, suggesting that dihydroartemisinin partly acts through the generation of reactive oxygen species. PMID:27447560

  19. In silico and in vivo anti-malarial studies of 18β glycyrrhetinic acid from Glycyrrhiza glabra.

    PubMed

    Kalani, Komal; Agarwal, Jyoti; Alam, Sarfaraz; Khan, Feroz; Pal, Anirban; Srivastava, Santosh Kumar

    2013-01-01

    Malaria is one of the most prevailing fatal diseases causing between 1.2 and 2.7 million deaths all over the world each year. Further, development of resistance against the frontline anti-malarial drugs has created an alarming situation, which requires intensive drug discovery to develop new, more effective, affordable and accessible anti-malarial agents possessing novel modes of action. Over the past few years triterpenoids from higher plants have shown a wide range of anti-malarial activities. As a part of our drug discovery program for anti-malarial agents from Indian medicinal plants, roots of Glycyrrhizaglabra were chemically investigated, which resulted in the isolation and characterization of 18β-glycyrrhetinic acid (GA) as a major constituent. The in vitro studies against P. falciparum showed significant (IC50 1.69 µg/ml) anti-malarial potential for GA. Similarly, the molecular docking studies showed adequate docking (LibDock) score of 71.18 for GA and 131.15 for standard anti-malarial drug chloroquine. Further, in silico pharmacokinetic and drug-likeness studies showed that GA possesses drug-like properties. Finally, in vivo evaluation showed a dose dependent anti-malarial activity ranging from 68-100% at doses of 62.5-250 mg/kg on day 8. To the best of our knowledge this is the first ever report on the anti-malarial potential of GA. Further work on optimization of the anti-malarial lead is under progress.

  20. Prescribing Pattern of Anti-malarial Drugs with Particular Reference to the use of Artesunate in Complicated Plasmodium Vivax Cases

    PubMed Central

    Singh, Ashutosh Kumar; Khan, Mohd Sajid

    2014-01-01

    Background: In developing countries, Malaria has been found to be one of the most common cause of fever and morbidity, particularly among infants and young children. Therefore, its drug utilization studies should be carried out to know the rationality of treatment. Aim: To evaluate the use of antimalarial agents in children with a diagnosis of Malaria and visited to OPD & IPD Paediatric department of a tertiary care teaching hospital. Materials and Methods: This was a prospective six months study based on a Medication Utilization Form, which has been designed in consultation with the paediatrician. One hundred eighty three children <12 y of age were selected on the basis of inclusion and exclusion criteria. Results: Out of 183 patients, 110 were infected with Plasmodium falciparum (60.10%) and 73 with Plasmodium vivax (39.89%). Most of the patients were male, 56.83% and 43.16% were female patients. Most of the complicated cases were found from Plasmodium falciparum (n = 110) than Plasmodium vivax (n=15). In prescriptions with monotherapy, Artesunate (n=101) was found to be the most commonly prescribed drug and in prescriptions containing more than one drug, Artesunate – lumefantrine (n=125) combinations were frequently used. Most of the drugs were prescribed by oral route (n=285), than the parenteral route (n=140). The average number of drugs per encounter was 2.32 and only 4.50% drugs were prescribed by generic name. Average drug cost per prescription in complicated cases was found to be higher (185.5 INR) than uncomplicated cases (115 INR). Conclusion: Artemisinin were used as first line drugs irrespective of the causative agent for malaria, which is not recommended, however has been found to be effective in complicated cases of Plasmodium vivax also. The cost of the prescription was higher. Interventions to rectify over prescription of injectables necessary to further improve rational drug use in our facility. Also, there should be an awareness program

  1. Factors related to compliance to anti-malarial drug combination: example of amodiaquine/sulphadoxine-pyrimethamine among children in rural Senegal

    PubMed Central

    Souares, Aurélia; Lalou, Richard; Sene, Ibra; Sow, Diarietou; Le Hesran, Jean-Yves

    2009-01-01

    Background The introduction of new anti-malarial treatment that is effective, but more expensive, raises questions about whether the high level of effectiveness observed in clinical trials can be found in a context of family use. The objective of this study was to determine the factors related to adherence, when using the amodiaquine/sulphadoxine-pyrimethamine (AQ/SP) association, a transitory strategy before ACT implementation in Senegal. Methods The study was conducted in five rural dispensaries. Children, between two and 10 years of age, who presented mild malaria were recruited at the time of the consultation and were prescribed AQ/SP. The child's primary caretaker was questioned at home on D3 about treatment compliance and factors that could have influenced his or her adherence to treatment. A logistic regression model was used for the analyses. Results The study sample included 289 children. The adherence rate was 64.7%. Two risks factors for non-adherence were identified: the children's age (8–10 years) (ORa = 3.07 [1.49–6.29]; p = 0.004); and the profession of the head of household (retailer/employee versus farmer) (ORa = 2.71 [1.34–5.48]; p = 0.006). Previously seeking care (ORa = 0.28 [0.105–0.736], p=0.001] satisfaction with received information (ORa = 0.45 [0.24–0.84]; p = 0.013), and the quality of history taking (ORa = 0.38 [0.21–0.69]; p = 0.001) were significantly associated with good compliance. Conclusion The results of the study show the importance of information and communication between caregivers and health center staff. The experience gained from this therapeutic transition emphasizes the importance of information given to the patients at the time of the consultation and drug delivery in order to improve drug use and thus prevent the emergence of rapid drug resistance. PMID:19497103

  2. Effect of selected anti-malarial drugs on the blood chemistry and brain serotonin levels in male rabbits.

    PubMed

    Eigbibhalu, Ukpo Grace; Albert Taiwo, Ebuehi Osaretin; Douglass, Idiakheua Akhabue; Abimbola, Efunogbon Aderonke

    2013-01-01

    The effects of oral administration of sulfadoxine - pyrimethamine (SP), artesunate (A) and sulfadoxine - pyrimethamine - artesunate (SPA) on blood chemistry and brain serotonin in rabbits were investigated. Forty rabbits were divided into four groups of ten animals each. The group that served as the control received 2ml of distilled water while the other groups were received 1.25/25mg base/kg body weight of SP, 3.3mg/kg body weight of A and 1.25/25mg base/kg body weight of SP plus 3.3mg/kg body weight of A respectively by oral route daily for 3 days in a week for four weeks. At the end of each week of drug administration, three rabbits from each group were anaesthetized, blood was taken from the jugular veins using sterile needle and serum was extracted. The rabbits were sacrificed by decapitation; the liver and brain tissues were excised and homogenized. Total blood protein, cholesterol, triglyceride, albumin, creatinine and urea concentrations, creatine kinase, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase, ALP activities were assayed using CX5 synchron autoanalyzer. The brain and liver serotonin levels were determined using high performance liquid chromatography (HPLC). There were no significant differences (P < 0.05) in the concentrations of serum albumin, urea, creatinine, cholesterol and triglyceride of rabbits administered SP, A and SPA for 4 weeks, except in serum total protein. No significant differences existed in the activities of AST, ALT and ALP, except in creatine kinase which was elevated in the control. The brain serotonin levels of rabbits administered SP, A and SPA were significantly higher as compared to the control throughout the duration of the study Data of the study indicate that oral administration of SP, A or SPA in rabbits do not affect blood chemistry, but affected brain serotonin levels and could alter some neural functions.

  3. Biological activities of nitidine, a potential anti-malarial lead compound

    PubMed Central

    2012-01-01

    Background Nitidine is thought to be the main active ingredient in several traditional anti-malarial remedies used in different parts of the world. The widespread use of these therapies stresses the importance of studying this molecule in the context of malaria control. However, little is known about its potential as an anti-plasmodial drug, as well as its mechanism of action. Methods In this study, the anti-malarial potential of nitidine was evaluated in vitro on CQ-sensitive and -resistant strains. The nitidine's selectivity index compared with cancerous and non-cancerous cell lines was then determined. In vivo assays were then performed, using the four-day Peter's test methodology. To gain information about nitidine's possible mode of action, its moment of action on the parasite cell cycle was studied, and its localization inside the parasite was determined using confocal microscopy. The in vitro abilities of nitidine to bind haem and to inhibit β-haematin formation were also demonstrated. Results Nitidine showed similar in vitro activity in CQ-sensitive and resistant strains, and also a satisfying selectivity index (> 10) when compared with a non-cancerous cells line. Its in vivo activity was moderate; however, no sign of acute toxicity was observed during treatment. Nitidine's moment of action on the parasite cycle showed that it could not interfere with DNA replication; this was consistent with the observation that nitidine did not localize in the nucleus, but rather in the cytoplasm of the parasite. Nitidine was able to form a 1-1 complex with haem in vitro and also inhibited β-haematin formation with the same potency as chloroquine. Conclusion Nitidine can be considered a potential anti-malarial lead compound. Its ability to complex haem and inhibit β-haematin formation suggests a mechanism of action similar to that of chloroquine. The anti-malarial activity of nitidine could therefore be improved by structural modification of this molecule to increase

  4. In vitro and in vivo anti-malarial activity of Boerhavia elegans and Solanum surattense

    PubMed Central

    2010-01-01

    Background There is an urgent need to identify new anti-malarial drug targets for both prophylaxis and chemotherapy, due to the increasing problem of drug resistance to malaria parasites. In the present study, the aim was to discover novel, effective plant-based extracts for the activity against malaria. Methods Ten plants found in Iran were selected by ethnobotanical survey of medicinal plants. The crude ethanolic extracts were tested for in vitro anti-plasmodial activity against two strains of Plasmodium falciparum: K1 (chloroquine-resistant strain) and CY27 (chloroquine-sensitive strain), using the parasite lactate dehydrogenase (pLDH) assay. The anti-plasmodial activity of the extracts was also assessed in the 4-day suppressive anti-malarial assay in mice inoculated with Plasmodium berghei (ANKA strain). Crude ethanolic extracts showed good anti-plasmodial activity were further fractionated by partitioning in water and dichloromethane. Results Of 10 plant species assayed, three species: Boerhavia elegans (Choisy), Solanum surattense (Burm.f.) and Prosopis juliflora (Sw.) showed promising anti-plasmodial activity in vitro (IC50 ≤ 50 μg/ml) and in vivo with no toxicity. The dichloromethane fraction of three extracts revealed stronger anti-plasmodial activity than the total extracts. Conclusion Anti-plasmodial activities of extracts of B. elegans and S. surattense are reported for the first time. PMID:20462416

  5. Fake anti-malarials: start with the facts.

    PubMed

    Kaur, Harparkash; Clarke, Siȃn; Lalani, Mirza; Phanouvong, Souly; Guérin, Philippe; McLoughlin, Andrew; Wilson, Benjamin K; Deats, Michael; Plançon, Aline; Hopkins, Heidi; Miranda, Debora; Schellenberg, David

    2016-02-13

    This meeting report presents the key findings and discussion points of a 1-day meeting entitled 'Fake anti-malarials: start with the facts' held on 28th May 2015, in Geneva, Switzerland, to disseminate the findings of the artemisinin combination therapy consortium's drug quality programme. The teams purchased over 10,000 samples, using representative sampling approaches, from six malaria endemic countries: Equatorial Guinea (Bioko Island), Cambodia, Ghana, Nigeria, Rwanda and Tanzania. Laboratory analyses of these samples showed that falsified anti-malarials (<8 %) were found in just two of the countries, whilst substandard artemisinin-based combinations were present in all six countries and, artemisinin-based monotherapy tablets are still available in some places despite the fact that the WHO has urged regulatory authorities in malaria-endemic countries to take measures to halt the production and marketing of these oral monotherapies since 2007. This report summarizes the presentations that reviewed the public health impact of falsified and substandard drugs, sampling strategies, techniques for drug quality analysis, approaches to strengthen health systems capacity for the surveillance of drug quality, and the ensuing discussion points from the dissemination meeting.

  6. Poor quality vital anti-malarials in Africa - an urgent neglected public health priority

    PubMed Central

    2011-01-01

    Background Plasmodium falciparum malaria remains a major public health problem. A vital component of malaria control rests on the availability of good quality artemisinin-derivative based combination therapy (ACT) at the correct dose. However, there are increasing reports of poor quality anti-malarials in Africa. Methods Seven collections of artemisinin derivative monotherapies, ACT and halofantrine anti-malarials of suspicious quality were collected in 2002/10 in eleven African countries and in Asia en route to Africa. Packaging, chemical composition (high performance liquid chromatography, direct ionization mass spectrometry, X-ray diffractometry, stable isotope analysis) and botanical investigations were performed. Results Counterfeit artesunate containing chloroquine, counterfeit dihydroartemisinin (DHA) containing paracetamol (acetaminophen), counterfeit DHA-piperaquine containing sildenafil, counterfeit artemether-lumefantrine containing pyrimethamine, counterfeit halofantrine containing artemisinin, and substandard/counterfeit or degraded artesunate and artesunate+amodiaquine in eight countries are described. Pollen analysis was consistent with manufacture of counterfeits in eastern Asia. These data do not allow estimation of the frequency of poor quality anti-malarials in Africa. Conclusions Criminals are producing diverse harmful anti-malarial counterfeits with important public health consequences. The presence of artesunate monotherapy, substandard and/or degraded and counterfeit medicines containing sub-therapeutic amounts of unexpected anti-malarials will engender drug resistance. With the threatening spread of artemisinin resistance to Africa, much greater investment is required to ensure the quality of ACTs and removal of artemisinin monotherapies. The International Health Regulations may need to be invoked to counter these serious public health problems. PMID:22152094

  7. The counterfeit anti-malarial is a crime against humanity: a systematic review of the scientific evidence

    PubMed Central

    2014-01-01

    Background The counterfeiting of anti-malarials represents a form of attack on global public health in which fake and substandard anti-malarials serve as de facto weapons of mass destruction, particularly in resource-constrained endemic settings, where malaria causes nearly 660,000 preventable deaths and threatens millions of lives annually. It has been estimated that fake anti-malarials contribute to nearly 450,000 preventable deaths every year. This crime against humanity is often underestimated or ignored. This study attempts to describe and characterize the direct and indirect effects of counterfeit anti-malarials on public health, clinical care and socio-economic conditions. Methods A search was performed using key databases, WHO documents, and English language search engines. Of 262 potential articles that were identified using a fixed set of criteria, a convenience sample of 105 appropriate articles was selected for this review. Results Artemisinin-based combination therapy (ACT) is an important tool in the fight against malaria, but a sizable number of patients are unable to afford to this first-line treatment. Consequently, patients tend to procure cheaper anti-malarials, which may be fake or substandard. Forensic palynology reveals that counterfeits originate in Asia. Fragile drug regulations, ineffective law-enforcement agencies and corruption further burden ailing healthcare facilities. Substandard/fake anti-malarials can cause (a) economic sabotage; (b) therapeutic failure; (c) increased risk of the emergence and spread of resistant strains of Plasmodium falciparum and Plasmodium vivax; (d) an undermining of trust/confidence in healthcare stakeholders/systems; and, (e) serious side effects or death. Conclusion Combating counterfeit anti-malarials is a complex task due to limited resources and poor techniques for the detection and identification of fake anti-malarials. This situation calls for sustainable, global, scientific research and policy change

  8. New developments in anti-malarial target candidate and product profiles.

    PubMed

    Burrows, Jeremy N; Duparc, Stephan; Gutteridge, Winston E; Hooft van Huijsduijnen, Rob; Kaszubska, Wiweka; Macintyre, Fiona; Mazzuri, Sébastien; Möhrle, Jörg J; Wells, Timothy N C

    2017-01-13

    A decade of discovery and development of new anti-malarial medicines has led to a renewed focus on malaria elimination and eradication. Changes in the way new anti-malarial drugs are discovered and developed have led to a dramatic increase in the number and diversity of new molecules presently in pre-clinical and early clinical development. The twin challenges faced can be summarized by multi-drug resistant malaria from the Greater Mekong Sub-region, and the need to provide simplified medicines. This review lists changes in anti-malarial target candidate and target product profiles over the last 4 years. As well as new medicines to treat disease and prevent transmission, there has been increased focus on the longer term goal of finding new medicines for chemoprotection, potentially with long-acting molecules, or parenteral formulations. Other gaps in the malaria armamentarium, such as drugs to treat severe malaria and endectocides (that kill mosquitoes which feed on people who have taken the drug), are defined here. Ultimately the elimination of malaria requires medicines that are safe and well-tolerated to be used in vulnerable populations: in pregnancy, especially the first trimester, and in those suffering from malnutrition or co-infection with other pathogens. These updates reflect the maturing of an understanding of the key challenges in producing the next generation of medicines to control, eliminate and ultimately eradicate malaria.

  9. Access to Artemisinin-Combination Therapy (ACT) and other Anti-Malarials: National Policy and Markets in Sierra Leone

    PubMed Central

    Amuasi, John H.; Diap, Graciela; Nguah, Samuel Blay; Karikari, Patrick; Boakye, Isaac; Jambai, Amara; Lahai, Wani Kumba; Louie, Karly S.; Kiechel, Jean-Rene

    2012-01-01

    Malaria remains the leading burden of disease in post-conflict Sierra Leone. To overcome the challenge of anti-malarial drug resistance and improve effective treatment, Sierra Leone adopted artemisinin-combination therapy artesunate-amodiaquine (AS+AQ) as first-line treatment for uncomplicated P. falciparum malaria. Other national policy anti-malarials include artemether-lumefantrine (AL) as an alternative to AS+AQ, quinine and artemether for treatment of complicated malaria; and sulphadoxine-pyrimethamine (SP) for intermittent preventive treatment (IPTp). This study was conducted to evaluate access to national policy recommended anti-malarials. A cross-sectional survey of 127 medicine outlets (public, private and NGO) was conducted in urban and rural areas. The availability on the day of the survey, median prices, and affordability policy and available non-policy anti-malarials were calculated. Anti-malarials were stocked in 79% of all outlets surveyed. AS+AQ was widely available in public medicine outlets; AL was only available in the private and NGO sectors. Quinine was available in nearly two-thirds of public and NGO outlets and over one-third of private outlets. SP was widely available in all outlets. Non-policy anti-malarials were predominantly available in the private outlets. AS+AQ in the public sector was widely offered for free. Among the anti-malarials sold at a cost, the same median price of a course of AS+AQ (US$1.56), quinine tablets (US$0.63), were found in both the public and private sectors. Quinine injection had a median cost of US$0.31 in the public sector and US$0.47 in the private sector, while SP had a median cost of US$0.31 in the public sector compared to US$ 0.63 in the private sector. Non-policy anti-malarials were more affordable than first-line AS+AQ in all sectors. A course of AS+AQ was affordable at nearly two days’ worth of wages in both the public and private sectors. PMID:23133522

  10. Anti-malarial activity of Holarrhena antidysenterica and Viola canescens, plants traditionally used against malaria in the Garhwal region of north-west Himalaya

    PubMed Central

    2011-01-01

    Background The increasing number of multidrug-resistant Plasmodium strains warrants exploration of new anti-malarials. Medicinal plant research has become more important, particularly after the development of Chinese anti-malarial drug artemisnin from Artemisia annua. The present study shows evaluation of anti-malarial effects of two plants commonly used against malaria in the Garhwal region of north-west Himalaya, in order to discover the herbal-based medicine. Methods In vitro anti-plasmodial sensitivity of plant extracts was assessed using schizont maturation and parasite lactate dehydrogenase (pLDH) assay. Cytotoxic activities of the examined extracts were determined on L-6 cells of rat skeletal muscle myoblast. The 4-day test for anti-malarial activity against a chloroquine sensitive Plasmodium berghei NK65 strain in Swiss albino mice was used for monitoring in vivo activity of plant extracts. Results Chloroform extract of H. antidysenterica (HA-2) and petroleum ether extract of V. canescens (VC-1) plants significantly reduced parasitaemia in P. berghei infected mice. The extract HA-2 showed in vitro anti-plasmodial activity with its IC50 value 5.5 μg/ml using pLDH assay and ED50 value 18.29 mg/kg in P. berghei infected Swiss albino mice. Similarly petroleum ether extract of V. canescens (VC-1) showed in vitro anti-plasmodial activity with its IC50 value 2.76 μg/ml using pLDH assay and ED50 15.8 mg/kg in P. berghei infected mice. The extracts coded as HA-2 at 30 mg/kg and VC-1 at 20 mg/kg exhibited parasite inhibition in mice: 73.2% and 63.0% respectively. Of these two plant extracts, petroleum ether extract of V. canescens was found slightly cytotoxic. Conclusion The present investigation reflects the use of these traditional medicinal plants against malaria and these plants may work as potential source in the development of variety of herbal formulations for the treatment of malaria. PMID:21288335

  11. Recent progress in the identification and development of anti-malarial agents using virtual screening based approaches.

    PubMed

    Shah, Priyanka; Tiwari, Sunita; Siddiqi, Mohammad Imran

    2015-01-01

    Malaria has continued to be one of the most perplexing diseases for biological science community around the world due to its prevalent devastating nature and quick developing resistance against the frontline drugs. Artimisinin-based combination therapy (ACT) has been so far found to be among the best therapies against Plasmodium pathogens but alarming emergence of resistance in parasites against every known chemotherapy has prompted the scientific community to step up all the efforts towards development of new and affordable anti-malarial drugs. Computer-aided approaches have received enormous attention in recent years in the field of identification and design of novel drugs. In this review, we summarize recently published research concerning the identification and development of anti-malarial compounds using virtual screening approaches. It would be admirable to discern the successful application of in silico studies for anti-malarial drug discovery hitherto and would certainly help in generating new avenues for pursuing integrated studies between the experimentalists and computational chemists in a systematic manner as a time and cost efficient alternative for future antimalarial drug discovery projects.

  12. Review of pyronaridine anti-malarial properties and product characteristics

    PubMed Central

    2012-01-01

    Pyronaridine was synthesized in 1970 at the Institute of Chinese Parasitic Disease and has been used in China for over 30 years for the treatment of malaria. Pyronaridine has high potency against Plasmodium falciparum, including chloroquine-resistant strains. Studies in various animal models have shown pyronaridine to be effective against strains resistant to other anti-malarials, including chloroquine. Resistance to pyronaridine appears to emerge slowly and is further retarded when pyronaridine is used in combination with other anti-malarials, in particular, artesunate. Pyronaridine toxicity is generally less than that of chloroquine, though evidence of embryotoxicity in rodents suggests use with caution in pregnancy. Clinical pharmacokinetic data for pyronaridine indicates an elimination T1/2 of 13.2 and 9.6 days, respectively, in adults and children with acute uncomplicated falciparum and vivax malaria in artemisinin-combination therapy. Clinical data for mono or combined pyronaridine therapy show excellent anti-malarial effects against P. falciparum and studies of combination therapy also show promise against Plasmodium vivax. Pyronaridine has been developed as a fixed dose combination therapy, in a 3:1 ratio, with artesunate for the treatment of acute uncomplicated P. falciparum malaria and blood stage P. vivax malaria with the name of Pyramax® and has received Positive Opinion by European Medicines Agency under the Article 58 procedure. PMID:22877082

  13. Anti-malarial market and policy surveys in sub-Saharan Africa.

    PubMed

    Diap, Graciela; Amuasi, John; Boakye, Isaac; Sevcsik, Ann-Marie; Pecoul, Bernard

    2010-04-23

    At a recent meeting (Sept 18, 2009) in which reasons for the limited access to artemisinin-based combination therapy (ACT) in sub-Saharan Africa were discussed, policy and market surveys on anti-malarial drug availability and accessibility in Burundi and Sierra Leone were presented in a highly interactive brainstorming session among key stakeholders across private, public, and not-for-profit sectors. The surveys, the conduct of which directly involved the national malaria control programme managers of the two countries, provides the groundwork for evidence-based policy implementation. The results of the surveys could be extrapolated to other countries with similar socio-demographic and malaria profiles. The meeting resulted in recommendations on key actions to be taken at the global, national, and community level for better ACT accessibility. At the global level, both public and private sectors have actions to take to strengthen policies that lead to the replacement of loose blister packs with fixed-dose ACT products, develop strategies to ban inappropriate anti-malarials and regulate those bans, and facilitate technology and knowledge transfer to scale up production of fixed-dose ACT products, which should be readily available and affordable to those patients who are in the greatest need of these medicines. At the national level, policies that regulate the anti-malarial medicines market should be enacted and enforced. The public sector, including funding donors, should participate in ensuring that the private sector is engaged in the ACT implementation process. Research similar to the surveys discussed is important for other countries to develop and evaluate the right incentives at a local level. At the community level, community outreach and education about appropriate preventive and treatment measures must continue and be strengthened, with service delivery systems developed within both public and private sectors, among other measures, to decrease access to

  14. Fourier transform infrared spectroscopy as a tool for identification of crude microbial extracts with anti-malarial potential.

    PubMed

    Sankarganesh, P; Joseph, Baby

    2016-01-01

    Fourier transform infrared (FT-IR) spectroscopy is an indispensable tool for identifying biologically active functional groups in uncharacterized crude samples. Here, using FT-IR spectrum analysis, we identified crude extracts of Streptomyces that have anti-malarial activities and conducted a statistical analysis of their spectra. Among the three crude microbial extracts tested herein, an aromatic amine C-N stretching functional group was observed in the spectra of Streptomyces sp. BJSG1 and BJSG4 crude extracts. These extracts showed promising activity against Plasmodium falciparum in vitro cultures with IC50 values of 0.5 for BJSG1 and 0.4μg/mL for BJSG4. The present results showed that FT-IR analysis is necessary for the primary analysis of unknown samples in anti-malarial drug development.

  15. CoMFA, CoMSIA, and docking studies on thiolactone-class of potent anti-malarials: identification of essential structural features modulating anti-malarial activity.

    PubMed

    Roy, Kuldeep K; Bhunia, Shome S; Saxena, Anil K

    2011-09-01

    The integrated ligand- and structure-based drug design techniques have been applied on a homogeneous dataset of thiolactone-class of potent anti-malarials, to explore the essential structural features for the inhibition of Plasmodium falciparum. Developed CoMFA (q(2) = 0.716) and CoMSIA (q(2) = 0.632) models well explained structure-activity variation in both the training (CoMFA R(2) = 0.948 & CoMSIA R(2) = 0.849) and test set (CoMFA R(2) (pred) = 0.789 & CoMSIA R(2) (pred) = 0.733) compounds. The docking and scoring of the most active compound 10 into the active site of high-resolution (2.35 Å) structure of FabB-TLM binary complex (PDB-ID: 1FJ4) indicated that thiolactone core of this compound forms bifurcated H-bonding with two catalytic residues His298 and His333, and its saturated decyl side group is stabilized by hydrophobic interactions with the residues of a small hydrophobic groove, illustrating that the active site architecture, including two catalytic histidines and a small hydrophobic groove, is vital for protein-ligand interaction. In particular, the length and flexibility of the side group attached to the position 5 of thiolactone have been observed to play a significant role in the interaction with FabB enzyme. These results present scope for rational design of thiolactone-class of compounds that could furnish improved anti-malarial activity.

  16. Natural products as starting points for future anti-malarial therapies: going back to our roots?

    PubMed Central

    2011-01-01

    Background The discovery and development of new anti-malarials are at a crossroads. Fixed dose artemisinin combination therapy is now being used to treat a hundred million children each year, with a cost as low as 30 cents per child, with cure rates of over 95%. However, as with all anti-infective strategies, this triumph brings with it the seeds of its own downfall, the emergence of resistance. It takes ten years to develop a new medicine. New classes of medicines to combat malaria, as a result of infection by Plasmodium falciparum and Plasmodium vivax are urgently needed. Results Natural product scaffolds have been the basis of the majority of current anti-malarial medicines. Molecules such as quinine, lapachol and artemisinin were originally isolated from herbal medicinal products. After improvement with medicinal chemistry and formulation technologies, and combination with other active ingredients, they now make up the current armamentarium of medicines. In recent years advances in screening technologies have allowed testing of millions of compounds from pharmaceutical diversity for anti-malarial activity in cellular assays. These initiatives have resulted in thousands of new sub-micromolar active compounds – starting points for new drug discovery programmes. Against this backdrop, the paucity of potent natural products identified has been disappointing. Now is a good time to reflect on the current approach to screening herbal medicinal products and suggest revisions. Nearly sixty years ago, the Chinese doctor Chen Guofu, suggested natural products should be approached by dao-xing-ni-shi or ‘acting in the reversed order’, starting with observational clinical studies. Natural products based on herbal remedies are in use in the community, and have the potential unique advantage that clinical observational data exist, or can be generated. The first step should be the confirmation and definition of the clinical activity of herbal medicinal products already

  17. Differences in anti-malarial activity of 4-aminoalcohol quinoline enantiomers and investigation of the presumed underlying mechanism of action

    PubMed Central

    2012-01-01

    Background A better anti-malarial efficiency and lower neurotoxicity have been reported for mefloquine (MQ) (+)- enantiomer. However, the importance of stereoselectivity remains poorly understood as the anti-malarial activity of pure enantiomer MQ analogues has never been described. Building on these observations, a series of enantiopure 4-aminoalcohol quinoline derivatives has previously been synthesized to optimize the efficiency and reduce possible adverse effects. Their in vitro activity on Plasmodium falciparum W2 and 3D7 strains is reported here along with their inhibition of β-haematin formation and peroxidative degradation of haemin, two possible mechanisms of action of anti-malarial drugs. Results The (S)-enantiomers of this series of 4-aminoalcohol quinoline derivatives were found to be at least as effective as both chloroquine (CQ) and MQ. The derivative with a 5-carbon side-chain length was the more efficient on both P. falciparum strains. (R )-enantiomers displayed an activity decreased by 2 to 15-fold as compared to their (S) counterparts. The inhibition of β-haematin formation was significantly stronger with all tested compounds than with MQ, irrespective of the stereochemistry. Similarly, the inhibition of haemin peroxidation was significantly higher for both (S) and (R)-enantiomers of derivatives with a side-chain length of five or six carbons than for MQ and CQ. Conclusions The prominence of stereochemistry in the anti-malarial activity of 4-aminoalcohol quinoline derivatives is confirmed. The inhibition of β-haematin formation and haemin peroxidation can be put forward as presumed mechanisms of action but do not account for the stereoselectivity of action witnessed in vitro. PMID:22401346

  18. Potent in vivo anti-malarial activity and representative snapshot pharmacokinetic evaluation of artemisinin-quinoline hybrids

    PubMed Central

    2013-01-01

    Background Because Plasmodium falciparum displays increase tolerance against the recommended artemisinin combination therapies (ACT), new classes of anti-malarial drugs are urgently required. Previously synthesized artemisinin-aminoquinoline hybrids were evaluated to ascertain whether the potent low nanomolar in vitro anti-plasmodial activity would carry over in vivo against Plasmodium vinckei. A snapshot pharmacokinetic analysis was carried out on one of the hybrids to obtain an indication of the pharmacokinetic properties of this class of anti-malarial drugs. Methods In vitro activity of hybrids 2 and 3 were determined against the 3D7 strain of P. falciparum. Plasmodium vinckei-infected mice were treated with hybrids 1 – 3 for four days at a dosage of 0.8 mg/kg, 2.5 mg/kg, 7.5 mg/kg or 15 mg/kg intraperitoneally (ip), or orally (per os) with 2.7 mg/kg, 8.3 mg/kg, 25 mg/kg or 50 mg/kg. Artesunate was used as reference drug. A snapshot oral and IV pharmacokinetic study was performed on hybrid 2. Results Hybrids 1 – 3 displayed potent in vivo anti-malarial activity with ED50 of 1.1, 1.4 and <0.8 mg/kg by the ip route and 12, 16 and 13 mg/kg per os, respectively. Long-term monitoring of parasitaemia showed a complete cure of mice (without recrudescence) at 15 mg/kg via ip route and at 50 mg/kg by oral route for hybrid 1 and 2, whereas artesunate was only able to provide a complete cure at 30 mg/kg ip and 80 mg/kg per os. Conclusions These compounds provide a new class of desperately needed anti-malarial drug. Despite a short half-life and moderate oral bioavailability, this class of compounds was able to cure malaria in mice at very low dosages. The optimum linker length for anti-malarial activity was found to be a diaminoalkyl chain consisting of two carbon atoms either methylated or unmethylated. PMID:23433124

  19. Discovery of a selective, safe and novel anti-malarial compound with activity against chloroquine resistant strain of Plasmodium falciparum

    PubMed Central

    Agarwal, Ankita; Paliwal, Sarvesh; Mishra, Ruchi; Sharma, Swapnil; Kumar Dwivedi, Anil; Tripathi, Renu; Gunjan, Sarika

    2015-01-01

    In recent years the DNA minor groove has attracted much attention for the development of anti-malarial agents. In view of this we have attempted to discover novel DNA minor groove binders through in-silico and in-vitro workflow. A rigorously validated pharmacophore model comprising of two positive ionizable (PI), one hydrophobic (HY) and one ring aromatic (RA) features was used to mine NCI chemical compound database. This led to retrieval of many hits which were screened on the basis of estimated activity, fit value and Lipinski’s violation. Finally two compounds NSC639017 and NSC371488 were evaluated for their in-vitro anti-malarial activities against Plasmodium falciparum 3D7 (CQ sensitive) and K1 (CQ resistant) strains by SYBR green-I based fluorescence assay. The results revealed that out of two, NSC639017 posses excellent anti-malarial activity particularly against chloroquine resistant strain and moreover NSC639017 also appeared to be safe (CC50 126.04 μg/ml) and selective during cytotoxicity evaluation. PMID:26346444

  20. Anti-malarial Activities of Two Soil Actinomycete Isolates from Sabah via Inhibition of Glycogen Synthase Kinase 3β

    PubMed Central

    Dahari, Dhiana Efani; Salleh, Raifana Mohamad; Mahmud, Fauze; Chin, Lee Ping; Embi, Noor; Sidek, Hasidah Mohd

    2016-01-01

    Exploiting natural resources for bioactive compounds is an attractive drug discovery strategy in search for new anti-malarial drugs with novel modes of action. Initial screening efforts in our laboratory revealed two preparations of soil-derived actinomycetes (H11809 and FH025) with potent anti-malarial activities. Both crude extracts showed glycogen synthase kinase 3β (GSK3β)-inhibitory activities in a yeast-based kinase assay. We have previously shown that the GSK3 inhibitor, lithium chloride (LiCl), was able to suppress parasitaemia development in a rodent model of malarial infection. The present study aims to evaluate whether anti-malarial activities of H11809 and FH025 involve the inhibition of GSK3β. The acetone crude extracts of H11809 and FH025 each exerted strong inhibition on the growth of Plasmodium falciparum 3D7 in vitro with 50% inhibitory concentration (IC50) values of 0.57 ± 0.09 and 1.28 ± 0.11 µg/mL, respectively. The tested extracts exhibited Selectivity Index (SI) values exceeding 10 for the 3D7 strain. Both H11809 and FH025 showed dosage-dependent chemo-suppressive activities in vivo and improved animal survivability compared to non-treated infected mice. Western analysis revealed increased phosphorylation of serine (Ser 9) GSK3β (by 6.79 to 6.83-fold) in liver samples from infected mice treated with H11809 or FH025 compared to samples from non-infected or non-treated infected mice. A compound already identified in H11809 (data not shown), dibutyl phthalate (DBP) showed active anti-plasmodial activity against 3D7 (IC50 4.87 ± 1.26 µg/mL which is equivalent to 17.50 µM) and good chemo-suppressive activity in vivo (60.80% chemo-suppression at 300 mg/kg body weight [bw] dosage). DBP administration also resulted in increased phosphorylation of Ser 9 GSK3β compared to controls. Findings from the present study demonstrate that the potent anti-malarial activities of H11809 and FH025 were mediated via inhibition of host GSK3β. In addition

  1. Anti-malarial activity and HS-SPME-GC-MS chemical profiling of Plinia cerrocampanensis leaf essential oil

    PubMed Central

    2014-01-01

    Background Plinia cerrocampanensis is an endemic plant of Panama. The leaf essential oil of this plant has shown antibacterial activity. However, anti-malarial activity and chemical profiling by HS-SPME-GC-MS of this essential oil have not been reported before. Methods Anti-malarial activity of the essential oil (EO) was evaluated in vitro against chloroquine-sensitive HB3 and chloroquine-resistant W2 strains of Plasmodium falciparum. Synergistic effect of chloroquine and the EO on parasite growth was evaluated by calculating the combination index. A methodology involving headspace solid phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS) was developed to investigate the composition of Plinia cerrocampanensis EO. Results Plinia cerrocampanensis EO showed a high anti-malarial activity and a synergistic interaction with chloroquine. The Plinia cerrocampanensis EO inhibited P. falciparum growth in vitro at an IC50 of 7.3 μg/mL. Chloroquine together with the EO decreased the IC50 of chloroquine from 0.1 μg/mL to 0.05 μg/mL, and of the EO from 7.3 μg/mL to 1.1 μg/mL. The measured combination index was 0.58, which clearly indicates that the EO acts synergistically with chloroquine. Since the EO maintained its inhibitory activity on the chloroquine-sensitive strain of the parasite, it could be acting by a different mechanism of action than chloroquine. The best HS-SPME-GC-MS analytical conditions were obtained when the temperature of extraction was 49°C, incubation time 14 min, and the time of extraction 10 min. This method allowed for the identification of 53 volatile constituents in the EO, including new compounds not reported earlier. Conclusions The anti-malarial activity exhibited by the Plinia cerrocampanensis EO may lend support for its possible use as an alternative for anti-malarial therapy. PMID:24410874

  2. The anti-malarial atovaquone increases radiosensitivity by alleviating tumour hypoxia

    PubMed Central

    Ashton, Thomas M.; Fokas, Emmanouil; Kunz-Schughart, Leoni A.; Folkes, Lisa K.; Anbalagan, Selvakumar; Huether, Melanie; Kelly, Catherine J.; Pirovano, Giacomo; Buffa, Francesca M.; Hammond, Ester M.; Stratford, Michael; Muschel, Ruth J.; Higgins, Geoff S.; McKenna, William Gillies

    2016-01-01

    Tumour hypoxia renders cancer cells resistant to cancer therapy, resulting in markedly worse clinical outcomes. To find clinical candidate compounds that reduce hypoxia in tumours, we conduct a high-throughput screen for oxygen consumption rate (OCR) reduction and identify a number of drugs with this property. For this study we focus on the anti-malarial, atovaquone. Atovaquone rapidly decreases the OCR by more than 80% in a wide range of cancer cell lines at pharmacological concentrations. In addition, atovaquone eradicates hypoxia in FaDu, HCT116 and H1299 spheroids. Similarly, it reduces hypoxia in FaDu and HCT116 xenografts in nude mice, and causes a significant tumour growth delay when combined with radiation. Atovaquone is a ubiquinone analogue, and decreases the OCR by inhibiting mitochondrial complex III. We are now undertaking clinical studies to assess whether atovaquone reduces tumour hypoxia in patients, thereby increasing the efficacy of radiotherapy. PMID:27453292

  3. Self-reported data: a major tool to assess compliance with anti-malarial combination therapy among children in Senegal

    PubMed Central

    2009-01-01

    Background Although there are many methods available for measuring compliance, there is no formal gold standard. Different techniques used to measure compliance were compared among children treated by the anti-malarial amodiaquine/sulphadoxine-pyrimethamine (AQ/SP) combination therapy, in use in Senegal between 2004 and 2006. Methods The study was carried out in 2004, in five health centres located in the Thies region (Senegal). Children who had AQ/SP prescribed for three and one day respectively at the health centre were recruited. The day following the theoretical last intake of AQ, venous blood, and urine samples were collected for anti-malarial drugs dosage. Caregivers and children above five years were interviewed concerning children's drug intake. Results Among the children, 64.7% adhered to 80% of the prescribed dose and only 37.7% were strict full adherent to the prescription. There was 72.7% agreement between self-reported data and blood drug dosage for amodiaquine treatment. Concerning SP, results found that blood dosages were 91.4% concordant with urine tests and 90% with self-reported data based on questionnaires. Conclusion Self-reported data could provide useful quantitative information on drug intake and administration. Under strict methodological conditions this method, easy to implement, can be used to describe patients' behaviors and their use of new anti-malarial treatment. Self-reported data is a major tool for assessing compliance in resource poor countries. Blood and urine drug dosages provide qualitative results that confirm any drug intake. Urine assays for SP could be useful to obtain public health data, for example on chemoprophylaxis among pregnant women. PMID:19922609

  4. Optimizing the programmatic deployment of the anti-malarials artemether-lumefantrine and dihydroartemisinin-piperaquine using pharmacological modelling

    PubMed Central

    2014-01-01

    Background Successful programmatic use of anti-malarials faces challenges that are not covered by standard drug development processes. The development of appropriate pragmatic dosing regimens for low-resource settings or community-based use is not formally regulated, even though these may alter factors which can substantially affect individual patient and population level outcome, such as drug exposure, patient adherence and the spread of drug resistance and can affect a drug’s reputation and its eventual therapeutic lifespan. Methods An in silico pharmacological model of anti-malarial drug treatment with the pharmacokinetic/pharmacodynamic profiles of artemether-lumefantrine (AM-LF, Coartem®) and dihydroartemisinin-piperaquine (DHA-PPQ, Eurartesim®) was constructed to assess the potential impact of programmatic factors, including regionally optimized, age-based dosing regimens, poor patient adherence, food effects and drug resistance on treatment outcome at population level, and compared both drugs’ susceptibility to these factors. Results Compared with DHA-PPQ, therapeutic effectiveness of AM-LF seems more robust to factors affecting drug exposure, such as age- instead of weight-based dosing or poor adherence. The model highlights the sub-optimally low ratio of DHA:PPQ which, in combination with the narrow therapeutic dose range of PPQ compared to DHA that drives the weight or age cut-offs, leaves DHA at a high risk of under-dosing. Conclusion Pharmacological modelling of real-life scenarios can provide valuable supportive data and highlight modifiable determinants of therapeutic effectiveness that can help optimize the deployment of anti-malarials in control programmes. PMID:24708571

  5. Development and Optimization of a Novel 384-Well Anti-Malarial Imaging Assay Validated for High-Throughput Screening

    PubMed Central

    Duffy, Sandra; Avery, Vicky M.

    2012-01-01

    With the increasing occurrence of drug resistance in the malaria parasite, Plasmodium falciparum, there is a great need for new and novel anti-malarial drugs. We have developed a 384-well, high-throughput imaging assay for the detection of new anti-malarial compounds, which was initially validated by screening a marine natural product library, and subsequently used to screen more than 3 million data points from a variety of compound sources. Founded on another fluorescence-based P. falciparum growth inhibition assay, the DNA-intercalating dye 4′,6-diamidino-2-phenylindole, was used to monitor changes in parasite number. Fluorescent images were acquired on the PerkinElmer Opera High Throughput confocal imaging system and analyzed with a spot detection algorithm using the Acapella data processing software. Further optimization of this assay sought to increase throughput, assay stability, and compatibility with our high-throughput screening equipment platforms. The assay typically yielded Z'-factor values of 0.5–0.6, with signal-to-noise ratios of 12. PMID:22232455

  6. The potential of anti-malarial compounds derived from African medicinal plants, part II: a pharmacological evaluation of non-alkaloids and non-terpenoids

    PubMed Central

    2014-01-01

    Malaria is currently a public health concern in many countries in the world due to various factors which are not yet under check. Drug discovery projects targeting malaria often resort to natural sources in the search for lead compounds. A survey of the literature has led to a summary of the major findings regarding plant-derived compounds from African flora, which have shown anti-malarial/antiplasmodial activities, tested by in vitro and in vivo assays. Considerations have been given to compounds with activities ranging from “very active” to “weakly active”, leading to >500 chemical structures, mainly alkaloids, terpenoids, flavonoids, coumarins, phenolics, polyacetylenes, xanthones, quinones, steroids and lignans. However, only the compounds that showed anti-malarial activity, from “very active” to “moderately active”, are discussed in this review. PMID:24602358

  7. The potential of anti-malarial compounds derived from African medicinal plants, part I: a pharmacological evaluation of alkaloids and terpenoids

    PubMed Central

    2013-01-01

    Traditional medicine caters for about 80% of the health care needs of many rural populations around the world, especially in developing countries. In addition, plant-derived compounds have played key roles in drug discovery. Malaria is currently a public health concern in many countries in the world due to factors such as chemotherapy faced by resistance, poor hygienic conditions, poorly managed vector control programmes and no approved vaccines. In this review, an attempt has been made to assess the value of African medicinal plants for drug discovery by discussing the anti-malarial virtue of the derived phytochemicals that have been tested by in vitro and in vivo assays. This survey was focused on pure compounds derived from African flora which have exhibited anti-malarial properties with activities ranging from “very active” to “weakly active”. However, only the compounds which showed anti-malarial activities from “very active” to “moderately active” are discussed in this review. The activity of 278 compounds, mainly alkaloids, terpenoids, flavonoids, coumarines, phenolics, polyacetylenes, xanthones, quinones, steroids, and lignans have been discussed. The first part of this review series covers the activity of 171 compounds belonging to the alkaloid and terpenoid classes. Data available in the literature indicated that African flora hold an enormous potential for the development of phytomedicines for malaria. PMID:24330395

  8. The potential of anti-malarial compounds derived from African medicinal plants, part I: a pharmacological evaluation of alkaloids and terpenoids.

    PubMed

    Amoa Onguéné, Pascal; Ntie-Kang, Fidele; Lifongo, Lydia Likowo; Ndom, Jean Claude; Sippl, Wolfgang; Mbaze, Luc Meva'a

    2013-12-13

    Traditional medicine caters for about 80% of the health care needs of many rural populations around the world, especially in developing countries. In addition, plant-derived compounds have played key roles in drug discovery. Malaria is currently a public health concern in many countries in the world due to factors such as chemotherapy faced by resistance, poor hygienic conditions, poorly managed vector control programmes and no approved vaccines. In this review, an attempt has been made to assess the value of African medicinal plants for drug discovery by discussing the anti-malarial virtue of the derived phytochemicals that have been tested by in vitro and in vivo assays. This survey was focused on pure compounds derived from African flora which have exhibited anti-malarial properties with activities ranging from "very active" to "weakly active". However, only the compounds which showed anti-malarial activities from "very active" to "moderately active" are discussed in this review. The activity of 278 compounds, mainly alkaloids, terpenoids, flavonoids, coumarines, phenolics, polyacetylenes, xanthones, quinones, steroids, and lignans have been discussed. The first part of this review series covers the activity of 171 compounds belonging to the alkaloid and terpenoid classes. Data available in the literature indicated that African flora hold an enormous potential for the development of phytomedicines for malaria.

  9. Anti-malarial activity of indole alkaloids isolated from Aspidosperma olivaceum

    PubMed Central

    2014-01-01

    Background Several species of Aspidosperma (Apocynaceae) are used as treatments for human diseases in the tropics. Aspidosperma olivaceum, which is used to treat fevers in some regions of Brazil, contains the monoterpenoid indole alkaloids (MIAs) aspidoscarpine, uleine, apparicine, and N-methyl-tetrahydrolivacine. Using bio-guided fractionation and cytotoxicity testing in a human hepatoma cell line, several plant fractions and compounds purified from the bark and leaves of the plant were characterized for specific therapeutic activity (and selectivity index, SI) in vitro against the blood forms of Plasmodium falciparum. Methods The activity of A. olivaceum extracts, fractions, and isolated compounds was evaluated against chloroquine (CQ)-resistant P. falciparum blood parasites by in vitro testing with radiolabelled [3H]-hypoxanthine and a monoclonal anti-histidine-rich protein (HRPII) antibody. The cytotoxicity of these fractions and compounds was evaluated in a human hepatoma cell line using a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, and the SI was calculated as the ratio between the toxicity and activity. Two leaf fractions were tested in mice with Plasmodium berghei. Results All six fractions from the bark and leaf extracts were active in vitro at low doses (IC50 < 5.0 μg/mL) using the anti-HRPII test, and only two (the neutral and basic bark fractions) were toxic to a human cell line (HepG2). The most promising fractions were the crude leaf extract and its basic residue, which had SIs above 50. Among the four pure compounds evaluated, aspidoscarpine in the bark and leaf extracts showed the highest SI at 56; this compound, therefore, represents a possible anti-malarial drug that requires further study. The acidic leaf fraction administered by gavage to mice with blood-induced malaria was also active. Conclusion Using a bio-monitoring approach, it was possible to attribute the anti-P. falciparum activity of A. olivaceum to

  10. A population genetic model for the initial spread of partially resistant malaria parasites under anti-malarial combination therapy and weak intrahost competition.

    PubMed

    Kim, Yuseob; Escalante, Ananias A; Schneider, Kristan A

    2014-01-01

    To develop public-health policies that extend the lifespan of affordable anti-malarial drugs as effective treatment options, it is necessary to understand the evolutionary processes leading to the origin and spread of mutations conferring drug resistance in malarial parasites. We built a population-genetic model for the emergence of resistance under combination drug therapy. Reproductive cycles of parasites are specified by their absolute fitness determined by clinical parameters, thus coupling the evolutionary-genetic with population-dynamic processes. Initial mutations confer only partial drug-resistance. Therefore, mutant parasites rarely survive combination therapy and within-host competition is very weak among parasites. The model focuses on the early phase of such unsuccessful recurrent mutations. This ends in the rare event of mutants enriching in an infected individual from which the successful spread of resistance over the entire population is initiated. By computer simulations, the waiting time until the establishment of resistant parasites is analysed. Resistance spreads quickly following the first appearance of a host infected predominantly by mutant parasites. This occurs either through a rare transmission of a resistant parasite to an uninfected host or through a rare failure of drugs in removing "transient" mutant alleles. The emergence of resistance is delayed with lower mutation rate, earlier treatment, higher metabolic cost of resistance, longer duration of high drug dose, and higher drug efficacy causing a stronger reduction in the sensitive and resistant parasites' fitnesses. Overall, contrary to other studies' proposition, the current model based on absolute fitness suggests that aggressive drug treatment delays the emergence of drug resistance.

  11. Thiamin supplementation does not reduce the frequency of adverse events after anti-malarial therapy among patients with falciparum malaria in southern Laos

    PubMed Central

    2014-01-01

    Background In a recent study one third of Lao patients presenting with uncomplicated Plasmodium falciparum malaria had biochemical evidence of thiamin deficiency, which was associated with a higher incidence of adverse events. Thiamin supplementation might, therefore, reduce adverse events in this population. Methods An exploratory, double-blind, parallel group, placebo-controlled, superiority trial of thiamin supplementation in patients of all ages with uncomplicated and severe falciparum malaria was conducted in Xepon District, Savannakhet Province, southern Laos. Patients were randomly assigned to either oral thiamin 10 mg/day for 7 days immediately after standard anti-malarial treatment then 5 mg daily until day 42, or identical oral placebo. Results After interim analyses when 630 patients (314 in thiamin and 316 in placebo groups) had been recruited, the trial was discontinued on the grounds of futility. On admission biochemical thiamin deficiency (alpha ≥ 25%) was present in 27% of patients and 9% had severe deficiency (alpha > 31%). After 42 days of treatment, the frequency of thiamin deficiency was lower in the thiamin (2%, 1% severe) compared to the placebo (11%, 3% severe) groups (p < 0.001 and p = 0.05), respectively. Except for diarrhoea, 7% in the placebo compared to 3% in the thiamin group (p = 0.04), and dizziness on day 1 (33% vs 25%, p = 0.045), all adverse events were not significantly different between the groups (p > 0.05). Clinical, haematological, and parasitological responses to treatment did not differ significantly between the two groups. Conclusion Thiamin supplementation reduced biochemical thiamin deficiency among Lao malaria patients following anti-malarial drug treatment, but it did not reduce the frequency of adverse events after anti-malarial therapy or have any detected clinical or parasitological impact. Trial registration ISRCTN 85411059 PMID:25027701

  12. Quality of anti-malarials collected in the private and informal sectors in Guyana and Suriname

    PubMed Central

    2012-01-01

    Background Despite a significant reduction in the number of malaria cases in Guyana and Suriname, this disease remains a major problem in the interior of both countries, especially in areas with gold mining and logging operations, where malaria is endemic. National malaria control programmes in these countries provide treatment to patients with medicines that are procured and distributed through regulated processes in the public sector. However, availability to medicines in licensed facilities (private sector) and unlicensed facilities (informal sector) is common, posing the risk of access to and use of non-recommended treatments and/or poor quality products. Methods To assess the quality of circulating anti-malarial medicines, samples were purchased in the private and informal sectors of Guyana and Suriname in 2009. The sampling sites were selected based on epidemiological data and/or distance from health facilities. Samples were analysed for identity, content, dissolution or disintegration, impurities, and uniformity of dosage units or weight variation according to manufacturer, pharmacopeial, or other validated method. Results Quality issues were observed in 45 of 77 (58%) anti-malarial medicines sampled in Guyana of which 30 failed visual & physical inspection and 18 failed quality control tests. The proportion of monotherapy and ACT medicines failing quality control tests was 43% (13/30) and 11% (5/47) respectively. A higher proportion of medicines sampled from the private sector 34% (11/32) failed quality control tests versus 16% (7/45) in the informal sector. In Suriname, 58 medicines were sampled, of which 50 (86%) were Artecom®, the fixed-dose combination of piperaquine-dihydroartemisinin-trimethoprim co-blistered with a primaquine phosphate tablet. All Artecom samples were found to lack a label claim for primaquine, thus failing visual and physical inspection. Conclusions The findings of the studies in both countries point to significant problems with

  13. A Water-Soluble Polysaccharide from the Fruit Bodies of Bulgaria inquinans (Fries) and Its Anti-Malarial Activity

    PubMed Central

    Bi, Hongtao; Han, Han; Li, Zonghong; Ni, Weihua; Chen, Yan; Zhu, Jingjing; Gao, Tingting; Hao, Miao; Zhou, Yifa

    2011-01-01

    A water-soluble polysaccharide (BIWS-4b) was purified from the fruit bodies of Bulgaria inquinans (Fries). It is composed of mannose (27.2%), glucose (15.5%) and galactose (57.3%). Its molecular weight was estimated to be 7.4 kDa (polydispersity index, Mw/Mn: 1.35). Structural analyses indicated that BIWS-4b mainly contains (1 → 6)-linked, (1 → 5)-linked and (1 → 5,6)-linked β-Galf units; (1 → 4)-linked and non-reducing terminal β-Glcp units; and (1 → 2)-linked, (1 → 6)-linked, (1 → 2,6)-linked and non-reducing terminal α-Manp units. When examined by the 4-day method and in a prophylactic assay in mice, BIWS-4b exhibited markedly suppressive activity against malaria while enhancing the activity of artesunate. Immunological tests indicated that BIWS-4b significantly enhanced macrophage phagocytosis and splenic lymphocyte proliferation in malaria-bearing mice and normal mice. The anti-malarial activity of BIWS-4b might be intermediated by enhancing immune competence and restoring artesunate-suppressed immune function. Thus, BIWS-4b is a potential adjuvant of anti-malaria drugs. PMID:21785644

  14. In silico analysis reveals the anti-malarial potential of quinolinyl chalcone derivatives.

    PubMed

    Thillainayagam, Mahalakshmi; Pandian, Lavanya; Murugan, Kumar Kalavathy; Vijayaparthasarathi, Vijayakumar; Sundaramoorthy, Sarveswari; Anbarasu, Anand; Ramaiah, Sudha

    2015-01-01

    In this study, the correlation between chemical structures and various parameters such as steric effects and electrostatic interactions to the inhibitory activities of quinolinyl chalcone derivatives is derived to identify the key structural elements required in the rational design of potent and novel anti-malarial compounds. The molecular docking simulations and Comparative Molecular Field Analysis (CoMFA) are carried out on 38 chalcones derivatives using Plasmodium falciparum lactate dehydrogenase (PfLDH) as potential target. Surflex-dock is used to determine the probable binding conformations of all the compounds at the active site of pfLDH and to identify the hydrogen bonding interactions which could be used to alter the inhibitory activities. The CoMFA model has provided statistically significant results with the cross-validated correlation coefficient (q(2)) of .850 and the non-cross-validated correlation coefficient (r(2)) of .912. Standard error of estimation (SEE) is .280 and the optimum number of component is five. The predictive ability of the resultant model is evaluated using a test set comprising of 13 molecules and the predicted r(2) value is .885. The results provide valuable insight for optimization of quinolinyl chalcone derivatives for better anti-malarial therapy.

  15. Structural characterisation of sporozoite components for a multistage, multi-epitope, anti-malarial vaccine.

    PubMed

    Patarroyo, Manuel E; Cifuentes, Gladys; Rodríguez, Raúl

    2008-01-01

    A totally effective anti-malarial vaccine must contain epitopes derived from multiple proteins found in different stages of the particular parasite involved in invasion. It must therefore include sporozoite molecules able to induce protective immunity thereby blocking the parasite's access to hepatic cells; thrombospondin-related anonymous protein (TRAP) is one of them. Conserved high activity binding peptides (HABPs) attaching themselves to hepatic cells were used in immunisation studies with the highly malaria-susceptible Aotus monkey. However, they had to be modified to render them immunogenic. The changes induced in lead peptide 3D structure were analysed by correlating such substitutions with the induction of high anti-sporozoite antibody levels in the experimental monkey model. The modification induced structural changes in most modified HABPs, changing them from random-coil or distorted type III beta-turn structures to classical type III or III' beta-turn, thereby allowing a better fit into the MHC-II-peptide-TCR complex since they bound with high affinity to purified HLA-DRbeta1* molecules. These are the first (TRAP) conserved HABPs corresponding to functionally active amino acid sequences in sporozoite invasion and mobility which, when modified, were able to induce very high anti-sporozoite antibody responses, leading to suggesting them as components in the first line of defence of a fully-effective, subunit-based, multi-epitope, multi-stage, synthetic anti-malarial vaccine.

  16. Self-medication with anti-malarials is a common practice in rural communities of Kilosa district in Tanzania despite the reported decline of malaria

    PubMed Central

    2014-01-01

    Background Self-medication has been widely practiced worldwide particularly in developing countries including Tanzania. In sub-Saharan Africa high incidences of malaria have contributed to self-medication with anti-malarial drugs. In recent years, there has been a gain in malaria control, which has led to decreased malaria transmission, morbidity and mortality. Therefore, understanding the patterns of self-medication during this period when most instances of fever are presumed to be due to non-malaria febrile illnesses is important. In this study, self-medication practice was assessed among community members and information on the habit of self-medication was gathered from health workers. Methods Twelve focus group discussions (FGD) with members of communities and 14 in-depth interviews (IDI) with health workers were conducted in Kilosa district, Tanzania. The transcripts were coded into different categories by MaxQDA software and then analysed through thematic content analysis. Results The study revealed that self-medication was a common practice among FGD participants. Anti-malarial drugs including sulphadoxine-pyrimethamine and quinine were frequently used by the participants for treatment of fever. Study participants reported that they visited health facilities following failure of self-medication or if there was no significant improvement after self-medication. The common reported reasons for self-medication were shortages of drugs at health facilities, long waiting time at health facilities, long distance to health facilities, inability to pay for health care charges and the freedom to choose the preferred drugs. Conclusion This study demonstrated that self-medication practice is common among rural communities in the study area. The need for community awareness is emphasized for correct and comprehensive information about drawbacks associated with self-medication practices. Deliberate efforts by the government and other stakeholders to improve health care

  17. Methods for implementing a medicine outlet survey: lessons from the anti-malarial market

    PubMed Central

    2013-01-01

    Background In recent years an increasing number of public investments and policy changes have been made to improve the availability, affordability and quality of medicines available to consumers in developing countries, including anti-malarials. It is important to monitor the extent to which these interventions are successful in achieving their aims using quantitative data on the supply side of the market. There are a number of challenges related to studying supply, including outlet sampling, gaining provider cooperation and collecting accurate data on medicines. This paper provides guidance on key steps to address these issues when conducting a medicine outlet survey in a developing country context. While the basic principles of good survey design and implementation are important for all surveys, there are a set of specific issues that should be considered when conducting a medicine outlet survey. Methods This paper draws on the authors’ experience of designing and implementing outlet surveys, including the lessons learnt from ACTwatch outlet surveys on anti-malarial retail supply, and other key studies in the field. Key lessons and points of debate are distilled around the following areas: selecting a sample of outlets; techniques for collecting and analysing data on medicine availability, price and sales volumes; and methods for ensuring high quality data in general. Results and conclusions The authors first consider the inclusion criteria for outlets, contrasting comprehensive versus more focused approaches. Methods for developing a reliable sampling frame of outlets are then presented, including use of existing lists, key informants and an outlet census. Specific issues in the collection of data on medicine prices and sales volumes are discussed; and approaches for generating comparable price and sales volume data across products using the adult equivalent treatment dose (AETD) are explored. The paper concludes with advice on practical considerations

  18. Pharmacologic Inhibition of CXCL10 in Combination with Anti-malarial Therapy Eliminates Mortality Associated with Murine Model of Cerebral Malaria

    PubMed Central

    Wilson, Nana O.; Solomon, Wesley; Anderson, Leonard; Patrickson, John; Pitts, Sidney; Bond, Vincent; Liu, Mingli; Stiles, Jonathan K.

    2013-01-01

    Despite appropriate anti-malarial treatment, cerebral malaria (CM)-associated mortalities remain as high as 30%. Thus, adjunctive therapies are urgently needed to prevent or reduce such mortalities. Overproduction of CXCL10 in a subset of CM patients has been shown to be tightly associated with fatal human CM. Mice with deleted CXCL10 gene are partially protected against experimental cerebral malaria (ECM) mortality indicating the importance of CXCL10 in the pathogenesis of CM. However, the direct effect of increased CXCL10 production on brain cells is unknown. We assessed apoptotic effects of CXCL10 on human brain microvascular endothelial cells (HBVECs) and neuroglia cells in vitro. We tested the hypothesis that reducing overexpression of CXCL10 with a synthetic drug during CM pathogenesis will increase survival and reduce mortality. We utilized atorvastatin, a widely used synthetic blood cholesterol-lowering drug that specifically targets and reduces plasma CXCL10 levels in humans, to determine the effects of atorvastatin and artemether combination therapy on murine ECM outcome. We assessed effects of atorvastatin treatment on immune determinants of severity, survival, and parasitemia in ECM mice receiving a combination therapy from onset of ECM (day 6 through 9 post-infection) and compared results with controls. The results indicate that CXCL10 induces apoptosis in HBVECs and neuroglia cells in a dose-dependent manner suggesting that increased levels of CXCL10 in CM patients may play a role in vasculopathy, neuropathogenesis, and brain injury during CM pathogenesis. Treatment of ECM in mice with atorvastatin significantly reduced systemic and brain inflammation by reducing the levels of the anti-angiogenic and apoptotic factor (CXCL10) and increasing angiogenic factor (VEGF) production. Treatment with a combination of atorvastatin and artemether improved survival (100%) when compared with artemether monotherapy (70%), p<0.05. Thus, adjunctively reducing CXCL10

  19. Culture-adapted Plasmodium falciparum isolates from UK travellers: in vitro drug sensitivity, clonality and drug resistance markers

    PubMed Central

    2013-01-01

    Background The screening of lead compounds against in vitro parasite cultures is an essential step in the development of novel anti-malarial drugs, but currently relies on laboratory parasite lines established in vitro during the last century. This study sought to establish in continuous culture a series of recent Plasmodium falciparum isolates to represent the current parasite populations in Africa, all of which are now exposed to artemisinin combination therapy. Methods Pre-treatment P. falciparum isolates were obtained in EDTA, and placed into continuous culture after sampling of DNA. One post-treatment blood sample was also collected for each donor to monitor parasite clonality during clearance in vivo. IC50 estimates were obtained for 11 anti-malarial compounds for each established parasite line, clonal multiplicity measured in vivo and in vitro, and polymorphic sites implicated in parasite sensitivity to drugs were investigated at the pfmdr1, pfcrt, pfdhfr, pfdhps and pfap2mu loci before and after treatment, and in the cultured lines. Results Plasmodium falciparum isolates from seven malaria patients with recent travel to three West African and two East African countries were successfully established in long-term culture. One of these, HL1211, was from a patient with recrudescent parasitaemia 14 days after a full course of artemether-lumefantrine. All established culture lines were shown to be polyclonal, reflecting the in vivo isolates from which they were derived, and at least two lines reliably produce gametocytes in vitro. Two lines displayed high chloroquine IC50 estimates, and carried the CVIET haplotype at codons 72–76, whereas the remaining five lines carried the CVMNK haplotype and were sensitive in vitro. All were sensitive to the endoperoxides dihydroartemisinin and OZ277, but IC50 estimates for lumefantrine varied, with the least sensitive parasites carrying pfmdr1 alleles encoding Asn at codon 86. Conclusions This study describes the

  20. Chinese propriety medicines: an "alternative modernity?" The case of the anti-malarial substance artemisinin in East Africa.

    PubMed

    Hsu, Elisabeth

    2009-01-01

    This article discusses various modes of "modernizing" traditional Chinese medical drugs (zhongyao [image: see text]) and transforming them into so-called Chinese propriety medicines (zhongchengyao [image: see text]) that are flooding the current neoliberal wellness markets. This article argues that the chemical procedures used in the manufacture of Chinese propriety medicines are highly culture-specific and deserve being considered as instantiations of an "alternative modernity" (e.g., Knauft 2002), rather than of "Westernization." These Western-Chinese combinations, produced in strife toward fulfilling Mao Zedong's Communist-revolutionary vision, have a potential to represent a critical alterity to Western health policies, challenging rhetoric against such combinations. However, as is also noted in this article based on ethnographic fieldwork in East Africa, their potential alterity has been corroded for at least two reasons. First, the medical rationale for dispensing these medications has been shaped by commercial demands in ways that have worked toward transforming the formerly scholarly Chinese medical tradition (as outlined by Bates 1995) into a consumer-near and popular "folk medicine" (as defined by Farquhar 1994:212). Second, the repertoire of Chinese propriety medicines is impoverished as its efficacious "alternatively modern" drugs are being redefined as "modern" biomedical drugs. The article concludes that the potentially critical alterity of any formerly scholarly traditional medicine is more likely to be lost in those fields of health care that are both highly commercialized and polarized by the biomedical imperative to distinguish between "traditional" and "modern" medicines. As example for demonstrating how contentious the issue is, qinghaosu [image: see text] (artemisinin) is put center stage. It is an anti-malarial substance which in the 1970s Chinese scientists extracted from the Chinese medical drug qinghao [image: see text] (Herba Artemisiae

  1. Synthesis and evaluation of phenoxyoxazaphospholidine, phenoxyoxazaphosphinane, and benzodioxaphosphininamine sulfides and related compounds as potential anti-malarial agents.

    PubMed

    Mara, Christine; Dempsey, Enda; Bell, Angus; Barlow, James W

    2013-06-15

    A series of phenoxyoxazaphospholidine, phenoxyoxazaphosphinane and benzodioxaphosphininamine sulfides and related cyclic organophosphorus compounds based on the lead anti-tubulin herbicides amiprophos methyl and butamifos were synthesised and evaluated for anti-malarial activity. Of these compounds, while none of the phenoxyoxazaphospholidines, phenoxyoxazaphosphinanes or benzodioxaphosphininamine sulphides were more potent than APM, phosphorothioamidate 30, a dual compound also bearing an aminoquinoline motif, showed promising activity against Plasmodium falciparum (IC50 0.038 μM) and warrants further study.

  2. Novel Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase with Anti-malarial Activity in the Mouse Model

    SciTech Connect

    Booker, Michael L.; Bastos, Cecilia M.; Kramer, Martin L.; Barker, Jr., Robert H.; Skerlj, Renato; Sidhu, Amar Bir; Deng, Xiaoyi; Celatka, Cassandra; Cortese, Joseph F.; Guerrero Bravo, Jose E.; Crespo Llado, Keila N.; Serrano, Adelfa E.; Angulo-Barturen, Iñigo; Jiménez-Díaz, María Belén; Viera, Sara; Garuti, Helen; Wittlin, Sergio; Papastogiannidis, Petros; Lin, Jing-wen; Janse, Chris J.; Khan, Shahid M.; Duraisingh, Manoj; Coleman, Bradley; Goldsmith, Elizabeth J.; Phillips, Margaret A.; Munoz, Benito; Wirth, Dyann F.; Klinger, Jeffrey D.; Wiegand, Roger; Sybertz, Edmund

    2010-11-22

    Plasmodium falciparum, the causative agent of the most deadly form of human malaria, is unable to salvage pyrimidines and must rely on de novo biosynthesis for survival. Dihydroorotate dehydrogenase (DHODH) catalyzes the rate-limiting step in the pyrimidine biosynthetic pathway and represents a potential target for anti-malarial therapy. A high throughput screen and subsequent medicinal chemistry program identified a series of N-alkyl-5-(1H-benzimidazol-1-yl)thiophene-2-carboxamides with low nanomolar in vitro potency against DHODH from P. falciparum, P. vivax, and P. berghei. The compounds were selective for the parasite enzymes over human DHODH, and x-ray structural data on the analog Genz-667348, demonstrated that species selectivity could be attributed to amino acid differences in the inhibitor-binding site. Compounds from this series demonstrated in vitro potency against the 3D7 and Dd2 strains of P. falciparum, good tolerability and oral exposure in the mouse, and ED{sub 50} values in the 4-day murine P. berghei efficacy model of 13-21 mg/kg/day with oral twice-daily dosing. In particular, treatment with Genz-667348 at 100 mg/kg/day resulted in sterile cure. Two recent analogs of Genz-667348 are currently undergoing pilot toxicity testing to determine suitability as clinical development candidates.

  3. Strategies for developing multi-epitope, subunit-based, chemically synthesized anti-malarial vaccines.

    PubMed

    Patarroyo, M E; Cifuentes, G; Bermúdez, A; Patarroyo, M A

    2008-10-01

    An anti-malarial vaccine against the extremely lethal Plasmodium falciparum is desperately needed. Peptides from this parasite's proteins involved in invasion and having high red blood cell-binding ability were identified; these conserved peptides were not immunogenic or protection-inducing when used for immunizing Aotus monkeys. Modifying some critical binding residues in these high-activiy binding peptides' (HABPs') attachment to red blood cells (RBC) allowed them to induce immunogenicity and protection against experimental challenge and acquire the ability to bind to specific HLA-DRp1* alleles. These modified HABPs adopted certain characteristic structural configurations as determined by circular dichroism (CD) and 1H nuclear magnetic resonance (NMR) associated with certain HLA-DRbeta1* haplotype binding activities and characteristics, such as a 2-angstroms-distance difference between amino acids fitting into HLA-DRp1 Pockets 1 to 9, residues participating in binding to HLA-DR pockets and residues making contact with the TCR, suggesting haplotype and allele-conscious TCR. This has been demonstrated in HLA-DR-like genotyped monkeys and provides the basis for designing high effective, subunit-based, multi-antigen, multi-stage, synthetic vaccines, for immediate human use, malaria being one of them.

  4. The development and validation of an LC-MS/MS method for the determination of a new anti-malarial compound (TK900D) in human whole blood and its application to pharmacokinetic studies in mice

    PubMed Central

    2014-01-01

    Background Malaria is one of the most lethal and life-threatening killer infectious diseases in the world, and account for the deaths of more than half a million people annually. Despite the remarkable achievement made in preventing and eradicating malaria, it still remains a threat to the public health and a burden to the global economy due to the emergence of multiple-drug resistant malaria parasites. Therefore, the need to develop new anti-malarial drugs is crucial. The chemistry department at the University of Cape Town synthesized a number of new CQ-like derivatives (TK-series), and evaluated them for in vitro activity against both CQ-sensitive and -resistant Plasmodium falciparum strains, and for general cytotoxicity against a Chinese Hamster Ovarian (CHO) mammalian cell line. The lead compounds from the TK-series were selected for a comprehensive pharmacokinetic (PK) evaluation in a mouse model. Methods A sensitive LC-MS/MS assay was developed for the quantitative determination of TK900D. Multiple reaction monitoring (MRM) in the positive ionization mode was used for detection. The analyte and the internal standard (TK900E) were isolated from blood samples by liquid-liquid extraction with ethyl acetate. Chromatographic separation was achieved with a Phenomenex® Kinetex C18 (100 × 2.0 mm id, 2.6 μm) analytical column, using a mixture of 0.1% formic acid and acetonitrile (50:50; v/v) as the mobile phase. The method was fully validated over concentrations that ranged from 3.910 to 1000 ng/ml, and used to evaluate the PK properties of the lead compounds in a mouse model. Results The assay was robust, with deviation not exceeding 11% for the intra- and inter-run precision and accuracy. Extraction recovery was consistent and more than 60%. PK evaluation showed that TK900D and TK900E have moderate oral bioavailability of 30.8% and 25.9%, respectively. The apparent half-life ranged between 4 to 6 h for TK900D and 3.6 to 4 h for TK900E. Conclusion The assay was

  5. From fever to anti-malarial: the treatment-seeking process in rural Senegal

    PubMed Central

    2010-01-01

    Background Currently less than 15% of children under five with fever receive recommended artemisinin-combination therapy (ACT), far short of the Roll Back Malaria target of 80%. To understand why coverage remains low, it is necessary to examine the treatment pathway from a child getting fever to receiving appropriate treatment and to identify critical blockages. This paper presents the application of such a diagnostic approach to the coverage of prompt and effective treatment of children with fever in rural Senegal. Methods A two-stage cluster sample household survey was conducted in August 2008 in Tambacounda, Senegal, to investigate treatment behaviour for children under five with fever in the previous two weeks. The treatment pathway was divided in to five key steps; the proportion of all febrile children reaching each step was calculated. Results were stratified by sector of provider (public, community, and retail). Logistic regression was used to determine predictors of treatment seeking. Results Overall 61.6% (188) of caretakers sought any advice or treatment and 40.3% (123) sought any treatment promptly within 48 hours. Over 70% of children taken to any provider with fever did not receive an anti-malarial. The proportion of febrile children receiving ACT within 48 hours was 6.2% (19) from any source; inclusion of correct dose and duration reduced this to 1.3%. The proportion of febrile children receiving ACT within 48 hours (not including dose & duration) was 3.0% (9) from a public provider, 3.0% (9) from a community source and 0.3% (1) from the retail sector. Inclusion of confirmed diagnosis within the public sector treatment pathway as per national policy increases the proportion of children receiving appropriate treatment with ACT in this sector from 9.4% (9/96) to an estimated 20.0% (9/45). Conclusions Process analysis of the treatment pathway for febrile children must be stratified by sector of treatment-seeking. In Tambacounda, Senegal, interventions

  6. Skeletal hybridization and PfRIO-2 kinase modeling for synthesis of α-pyrone analogs as anti-malarial agent.

    PubMed

    Parveen, Afsana; Chakraborty, Arnish; Konreddy, Ananda Kumar; Chakravarty, Harapriya; Sharon, Ashoke; Trivedi, Vishal; Bal, Chandralata

    2013-01-01

    The pharmacophoric hybridization and computational design approach were applied to generate a novel series of α-pyrone analogs as plausible anti-malarial lead candidate. A putative active site in flexible loop close to wing-helix domain of PfRIO2 kinase was explored computationally to understand the molecular basis of ligand binding. All the synthesized molecules (3a-g) exhibited in vitro antimalarial activity. Oxidative stress induced by 3a-d were calculated and found to be significantly higher in case of 3b. Therefore, 3b, which shown most significant result was identified as promising lead for further SAR study to develop potent anti-malarials.

  7. Combination treatment of glioblastoma multiforme cell lines with the anti-malarial artesunate and the epidermal growth factor receptor tyrosine kinase inhibitor OSI-774.

    PubMed

    Efferth, Thomas; Ramirez, Tzutzuy; Gebhart, Erich; Halatsch, Marc-Eric

    2004-05-01

    New drugs and combination modalities for otherwise non-responsive brain tumors are urgently required. The anti-malarial artesunate (ART) and the EGFR tyrosine kinase inhibitor OSI-774 reveal profound cytotoxic activity. The effectiveness of a combination treatment and the underlying molecular determinants of cellular response are unknown. In the present investigation, we studied ART and OSI-774 in glioblastoma multiforme (GBM) cell lines. Supra-additive inhibition of cell growth was observed in U-87MG.DeltaEGFR cells transduced with a deletion-mutant constitutively active EGFR gene, while additive effects were present in cells transduced with wild-type EGFR (U-87MG.WT-2N), kinase-deficient EGFR (U-87MG.DK-2N), mock vector controls (U-87MG.LUX), or non-transduced parental U-87MG cells. Among nine other non-transduced GBM cell lines, supra-additive effects were found in two cell lines (G-210GM, G-599GM), while ART and OSI-774 acted in an additive manner in the other seven cell lines (G-211GM, G-750GM, G-1163GM, G-1187GM, G-1265GM, G-1301GM, and G-1408GM). Sub-additive or antagonistic effects were not observed. Genomic gains and losses of genetic material in the non-transduced cell lines as assessed by comparative genomic hybridization were correlated with the IC(50) values for ART and OSI-774 and subsequently subjected to hierarchical cluster analysis and cluster image mapping. A genomic profile of imbalances was detected that predicted cellular response to ART and OSI-774. The genes located at the genomic imbalances of interest may serve as candidate resistance genes of GBM cells towards ART and OSI-774. In conclusion, the combination treatment of ART and OSI-774 resulted in an increased growth inhibition of GBM cell lines as compared to each drug alone.

  8. Synthesis, biophysical, and biological studies of wild-type and mutant psalmopeotoxins--anti-malarial cysteine knot peptides from Psalmopoeus cambridgei.

    PubMed

    Kamolkijkarn, Pacharin; Prasertdee, Thitawan; Netirojjanakul, Chawita; Sarnpitak, Pakornwit; Ruchirawat, Somsak; Deechongkit, Songpon

    2010-04-01

    Psalmopeotoxin I and II (PcFK1 and PcFK2), an anti-malarial peptide first extracted from Psalmopoeus cambridgei was synthesized and characterized. Both peptides belong to the Inhibitor Cystine Knot (ICK) superfamily, containing three disulfide bridges. The six cysteine residues are conserved similar to other members of the ICK superfamily, suggesting their critical role for either folding or function. In this study, the peptides were synthesized using Fmoc solid-phase peptide synthesis (SPPS). The three disulfide bonds of were constructed by regioselective and random oxidative approaches. The resulting disulfide bond patterns were verified by the HPLC-MS analysis of intact peptides and by the disulfide bond mapping using tryptic digestion. Implications of the disulfide bonds on the biophysical and biological properties of PcFKs were studied using three disulfide mutants in which a particular pair of cysteines was replaced with two isosteric serine residues. Structures and biophysical characteristics of all variants were studied using far-UV CD and fluorescence spectroscopy. Biological activities of all variants were evaluated using antiplasmodial assay against the K1 multi-drug-resistant strain of P. falciparum. The experimental results showed that the three disulfide bridges could not be correctly synthesized by the random oxidative strategy. Structural and biophysical analyses revealed that all variants had similar structures to the twisted beta-sheet. However, the studies of disulfide bond removal indicated that each disulfide bond had different effects on both biophysical and biological activities of PcFKs. Correlation of biophysical parameters and biological activities showed that both PcFKs may have different mechanisms of actions for antiplasmodial activity.

  9. Anti-malarials exert a protective effect while Mestizo patients are at increased risk of developing SLE renal disease: data from a Latin-American cohort

    PubMed Central

    Pons-Estel, Guillermo J.; Alarcón, Graciela S.; Hachuel, Leticia; Boggio, Gabriela; Wojdyla, Daniel; Pascual-Ramos, Virginia; Soriano, Enrique R.; Saurit, Verónica; Cavalcanti, Fernando S.; Guzman, Renato A.; Guibert-Toledano, Marlene; Sauza del Pozo, Maria J.; Amigo, Mary-Carmen; Alva, Magaly; Esteva-Spinetti, Maria H.

    2012-01-01

    Objective. To examine the role of ethnicity and the use of anti-malarials (protective) on lupus renal disease. Methods. A nested case–control study (1:2 proportion, n = 265 and 530) within GLADEL's (Grupo Latino Americano De Estudio de Lupus) longitudinal inception cohort was carried out. The end-point was ACR renal criterion development after diagnosis. Cases and controls were matched for follow-up time (end-point or a comparable time, respectively). Renal disease predictors were examined by univariable and multivariable analyses. Additional analyses were done to determine if the protective effect of anti-malarials persisted after adjusting for intake-associated confounders. Results. Of the cases, 233 (87.9%) were women; their mean (s.d.) age at diagnosis was 28.0 (11.9) years and their median (Q3–Q1 interquartile range) follow-up time for cases and controls was 8.3 months (Q3–Q1: 23.5); 56.6% of the cases and 74.3% of the controls were anti-malarial users. Mestizo ethnicity [odds ratio (OR) 1.72, 95% CI 1.19, 2.48] and hypertension (OR 2.26, 95% CI 1.38, 3.70) were independently associated with a higher risk of renal disease, whereas anti-malarial use (OR 0.39, 95% CI 0.26, 0.58), older age at disease onset (OR 0.98, 95% CI 0.96, 0.99) and female gender (OR 0.56, 95% CI 0.32, 0.99) were negatively associated with such occurrence. After adjusting for variables associated with their intake, the protective effect of anti-malarials on renal disease occurrence persisted (OR 0.38, 95% CI 0.25, 0.58). Conclusion. Mestizo patients are at increased risk of developing renal disease, whereas anti-malarial use protects patients from such an occurrence. PMID:22389125

  10. A Systematic Review of Anti-malarial Properties, Immunosuppressive Properties, Anti-inflammatory Properties, and Anti-cancer Properties of Artemisia Annua

    PubMed Central

    Alesaeidi, Samira; Miraj, Sepide

    2016-01-01

    Artemisia annua belongs to the asteraceae family, indigenous to the mild climate of Asia. The aim of this study was to overview its anti-malarial properties, immunosuppressive properties, anti-inflammatory properties and anti-cancer properties. This systematic review was carried out by searching studies in PubMed, Medline, Web of Science, and IranMedex databases. The initial search strategy identified approximately ninety eight references. In this study, forty six studies were accepted for further screening and met all of our inclusion. The search terms were “Artemisia annua”, “therapeutic properties”, “and pharmacological effects”. Artemisia annua is commonly used for its anti-malarial, immunosuppressive anti-inflammatory properties. Artemisia annua contributes to the treatment of various diseases such as diabetes, heart diseases, arthritis and eczema and possesses various effects such as antibacterial, antioxidant, anticoccidial, and antiviral effects. Furthermore, it was said to be good for cancer treatment. In this study, anti-malarial, immunosuppressive, anti-inflammatory properties of this plant are presented using published articles in scientific sites. PMID:27957318

  11. Development and evaluation of anti-malarial bio-conjugates: artesunate-loaded nanoerythrosomes.

    PubMed

    Agnihotri, Jaya; Saraf, Shubhini; Singh, Sobhna; Bigoniya, Papiya

    2015-10-01

    Biodegradable cellular carrier has desired properties for achieving effective long-term controlled release of drugs having short half life. To reduce the undesired effects of drug, advanced drug delivery systems are needed which are based on specific cell targeting module. Artesunate (ART) conjugation on nanoerythrosomes (NE) can have controlled delivery to avoid drug leakage, increase the stability, and reduce cost and toxicities. In this study nanosized lipoprotein membrane vesicles bearing ART were prepared by extrusion method. Developed ART-NE conjugate formulations were optimized on the basis of vesicle morphology, size and size distribution, polydispersity index, integrity of membrane, loaded drug concentration, drug leakage, effect of temperature and viscosity, syringeability, in vitro release profile and in vivo plasma concentration estimation studies. Fourier transform infrared (FTIR) spectroscopy reveals that lipid chain order of RBCs are insignificantly affected in moderate conditions after ART loading. The formulated ART-NE carrier revealed non aggregated, uniformly sized particles with smooth surfaces. The maximum drug loading was found to be 25.20 ± 1.3 μg/ml. ART-NE formulation was best fit for zero order kinetics and was found to be capable of controlled release of drug for 8 hrs. ART-NE formulation showed good redispersibility with desirable properties for parenteral administration. Formulation was stable when subjected to stress by centrifugal force of 7500 rpm and could bear turbulence shock of 15 passes from hypodermic needle of size 23 gauges. The ART-NE formulation administered intravenously showed higher plasma concentration compared to free drug signifying not only controlled release but higher rate of in vivo release. The developed formulation exhibited zero order release profile as per kinetic study analysis suggesting the suitability of carrier for the sustained and targeted delivery of ART. The developed ART-NE drug delivery system

  12. Anti-malarial prescriptions in three health care facilities after the emergence of chloroquine resistance in Niakhar, Senegal (1992–2004)

    PubMed Central

    Munier, Aline; Diallo, Aldiouma; Cot, Michel; Ndiaye, Ousmane; Arduin, Pascal; Chippaux, Jean-Philippe

    2009-01-01

    Background In the rural zone of Niakhar in Senegal, the first therapeutic failures for chloroquine (CQ) were observed in 1992. In 2003, the national policy regarding first-line treatment of uncomplicated malaria was modified, replacing CQ by a transitory bi-therapy amodiaquine/sulphadoxine-pyrimethamine (AQ/SP), before the implementation of artemisinin-based combination therapy (ACT) in 2006. The aims of the study were to assess the evolution of anti-malarial prescriptions in three health care facilities between 1992 and 2004, in parallel with increasing CQ resistance in the region. Methods The study was conducted in the area of Niakhar, a demographic surveillance site located in a sahelo-sudanese region of Senegal, with mesoendemic and seasonal malaria transmission. Health records of two public health centres and a private catholic dispensary were collected retrospectively to cover the period 1992–2004. Results Records included 110,093 consultations and 292,965 prescribed treatments. Twenty-five percent of treatments were anti-malarials, prescribed to 49% of patients. They were delivered all year long, but especially during the rainy season, and 20% of patients with no clinical malaria diagnosis received anti-malarials. Chloroquine and quinine represented respectively 55.7% and 34.6% of prescribed anti-malarials. Overall, chloroquine prescriptions rose from 1992 to 2000, in parallel with clinical malaria; then the CQ prescription rate decreased from 2000 and was concomitant with the rise of SP and the persistence of quinine use. AQ and SP were mainly used as bi-therapy after 2003, at the time of national treatment policy change. Conclusion The results show the overall level of anti-malarial prescription in the study area for a considerable number of patients over a large period of time. Even though resistance to CQ rapidly increased from 1992 to 2001, no change in CQ prescription was observed until the early 2000s, possibly due to the absence of an obvious

  13. Mind the gaps - the epidemiology of poor-quality anti-malarials in the malarious world - analysis of the WorldWide Antimalarial Resistance Network database

    PubMed Central

    2014-01-01

    Background Poor quality medicines threaten the lives of millions of patients and are alarmingly common in many parts of the world. Nevertheless, the global extent of the problem remains unknown. Accurate estimates of the epidemiology of poor quality medicines are sparse and are influenced by sampling methodology and diverse chemical analysis techniques. In order to understand the existing data, the Antimalarial Quality Scientific Group at WWARN built a comprehensive, open-access, global database and linked Antimalarial Quality Surveyor, an online visualization tool. Analysis of the database is described here, the limitations of the studies and data reported, and their public health implications discussed. Methods The database collates customized summaries of 251 published anti-malarial quality reports in English, French and Spanish by time and location since 1946. It also includes information on assays to determine quality, sampling and medicine regulation. Results No publicly available reports for 60.6% (63) of the 104 malaria-endemic countries were found. Out of 9,348 anti-malarials sampled, 30.1% (2,813) failed chemical/packaging quality tests with 39.3% classified as falsified, 2.3% as substandard and 58.3% as poor quality without evidence available to categorize them as either substandard or falsified. Only 32.3% of the reports explicitly described their definitions of medicine quality and just 9.1% (855) of the samples collected in 4.6% (six) surveys were conducted using random sampling techniques. Packaging analysis was only described in 21.5% of publications and up to twenty wrong active ingredients were found in falsified anti-malarials. Conclusions There are severe neglected problems with anti-malarial quality but there are important caveats to accurately estimate the prevalence and distribution of poor quality anti-malarials. The lack of reports in many malaria-endemic areas, inadequate sampling techniques and inadequate chemical analytical methods and

  14. Context Sensitive Modeling of Cancer Drug Sensitivity

    PubMed Central

    Chen, Bo-Juen; Litvin, Oren; Ungar, Lyle; Pe’er, Dana

    2015-01-01

    Recent screening of drug sensitivity in large panels of cancer cell lines provides a valuable resource towards developing algorithms that predict drug response. Since more samples provide increased statistical power, most approaches to prediction of drug sensitivity pool multiple cancer types together without distinction. However, pan-cancer results can be misleading due to the confounding effects of tissues or cancer subtypes. On the other hand, independent analysis for each cancer-type is hampered by small sample size. To balance this trade-off, we present CHER (Contextual Heterogeneity Enabled Regression), an algorithm that builds predictive models for drug sensitivity by selecting predictive genomic features and deciding which ones should—and should not—be shared across different cancers, tissues and drugs. CHER provides significantly more accurate models of drug sensitivity than comparable elastic-net-based models. Moreover, CHER provides better insight into the underlying biological processes by finding a sparse set of shared and type-specific genomic features. PMID:26274927

  15. [Development of anti-malarial vaccines and need for clinical trials in accordance with international standards in South Africa].

    PubMed

    Doumbo, O K; Djimdé, A A; Théra, M A

    2008-06-01

    In the 20th century malaria remains a major problem of public health in sub-Saharan Africa. This haemosporidium discovered in Africa by Laveran in 1880, kills one child every 30 seconds which amounts to three "tsunami" flowing each year into the African continent. The current international solidarity raises new hopes as regards the possibility to suppress the morbidity effects on the population's health condition. In order to be efficient, today's strategies (impregnated mosquito nets, intermittent preventive treatments, artemisinin based combination therapy) should reach at least 80% of the targeted population (pregnant women and children). By 2025, the uncontrolled urbanization of the African population and the social disorders will make a new population a target for malaria. The new data of functional genomics and proteonics open new avenues of research for new mechanisms, new therapeutics and vaccine targets and new tools of diagnosis and prognosis. The current candidate vaccines of the first generation have allowed the development of African competences in clinical trials of international standard. Although they represent scientific advances they will not resolve the problem of public health. Research on candidate vaccines of 2nd and 3rd generation remains a challenge for the international scientific community. Africa should play a determining role in this process. Scientific information on the field remains essential for these generations of new anti-malarial vaccines. The ethical aspects regarding those clinical trials and actions of public health and research remain an universal necessity Deontology and ethics are two complementary approaches for the good practice of medicine and research of a good practitioner. For the protection and advantages of the patient and/or volunteer of the research are the cornerstones of the ethical approach. The scientific quality of a research protocol submitted to an independent research ethics committee and the volunteer 's

  16. Anti-malarial activity of a non-piperidine library of next-generation quinoline methanols

    PubMed Central

    2010-01-01

    Background The clinical utility for mefloquine has been eroded due to its association with adverse neurological effects. Better-tolerated alternatives are required. The objective of the present study was the identification of lead compounds that are as effective as mefloquine, but exhibit physiochemical properties likely to render them less susceptible to passage across the blood-brain barrier. Methods A library of drug-like non-piperidine analogs of mefloquine was synthesized. These compounds are diverse in structure and physiochemical properties. They were screened in appropriate in vitro assays and evaluated in terms of their potential as lead compounds. The correlation of specific structural attributes and physiochemical properties with activity was assessed. Results The most potent analogs were low molecular weight unconjugated secondary amines with no heteroatoms in their side-chains. However, these compounds were more metabolically labile and permeable than mefloquine. In terms of physiochemical properties, lower polar surface area, lower molecular weight, more freely rotatable bonds and fewer H-bond acceptors were associated with greater potency. There was no such relationship between activity and LogP, LogD or the number of hydrogen bond donors (HBDs). The addition of an H-bond donor to the side-chain yielded a series of active diamines, which were as metabolically stable as mefloquine but showed reduced permeability. Conclusions A drug-like library of non-piperidine analogs of mefloquine was synthesized. From amongst this library an active lead series of less permeable, but metabolically stable, diamines was identified. PMID:20149249

  17. Drugs use pattern for uncomplicated malaria in medicine retail outlets in Enugu urban, southeast Nigeria: implications for malaria treatment policy

    PubMed Central

    2014-01-01

    Background Malaria treatment policy recommends regular monitoring of drug utilization to generate information for ensuring effective use of anti-malarial drugs in Nigeria. This information is currently limited in the retail sector which constitutes a major source of malaria treatment in Nigeria, but are characterized by significant inappropriate use of drugs. This study analyzed the use pattern of anti-malarial drugs in medicine outlets to assess the current state of compliance to policy on the use of artemisinin-based combination therapy (ACT). Methods A prospective cross-sectional survey of randomly selected medicine outlets in Enugu urban, southeast Nigeria, was conducted between May and August 2013, to determine the types, range, prices, and use pattern of anti-malarial drugs dispensed from pharmacies and patent medicine vendors (PMVs). Data were collected and analyzed for anti-malarial drugs dispensed for self-medication to patients, treatment by retail outlets and prescription from hospitals. Results A total of 1,321 anti-malarial drugs prescriptions were analyzed. ACT accounted for 72.7%, while monotherapy was 27.3%. Affordable Medicines Facility-malaria (AMFm) drugs contributed 33.9% (326/961) of ACT. Artemether-lumefantrine (AL), 668 (50.6%) was the most used anti-malarial drug, followed by monotherapy sulphadoxine-pyrimethamine (SP), 248 (18.8%). Median cost of ACT at $2.91 ($0.65-7.42) per dose, is about three times the median cost of monotherapy, $0.97 ($0.19-13.55). Total cost of medication (including co-medications) with ACT averaged $3.64 (95% CI; $3.53-3.75) per prescription, about twice the mean cost of treatment with monotherapy, $1.83 (95% CI; $1.57-2.1). Highest proportion 46.5% (614), of the anti-malarial drugs was dispensed to patients for self-treatment. Treatment by retail outlets accounted for 35.8% while 17.7% of the drugs were dispensed from hospital prescriptions. Self-medication, 82%, accounted for the highest source of monotherapy and

  18. Mining of miRNAs and potential targets from gene oriented clusters of transcripts sequences of the anti-malarial plant, Artemisia annua.

    PubMed

    Pérez-Quintero, Alvaro L; Sablok, Gaurav; Tatarinova, Tatiana V; Conesa, Ana; Kuo, Jimmy; López, Camilo

    2012-04-01

    miRNAs involved in the biosynthesis of artemisinin, an anti-malarial compound form the plant Artemisia annua, have been identified using computational approaches to find conserved pre-miRNAs in available A. annua UniGene collections. Eleven pre-miRNAs were found from nine families. Targets predicted for these miRNAs were mainly transcription factors for conserved miRNAs. No target genes involved in artemisinin biosynthesis were found. However, miR390 was predicted to target a gene involved in the trichome development, which is the site of synthesis of artemisinin and could be a candidate for genetic transformation aiming to increase the content of artemisinin. Phylogenetic analyses were carried out to determinate the relation between A. annua and other plant pre-miRNAs: the pre-miRNA-based phylogenetic trees failed to correspond to known phylogenies, suggesting that pre-miRNA primary sequences may be too variable to accurately predict phylogenetic relations.

  19. The anti-malarial artemisinin inhibits pro-inflammatory cytokines via the NF-κB canonical signaling pathway in PMA-induced THP-1 monocytes.

    PubMed

    Wang, Yue; Huang, Zhouqing; Wang, Liansheng; Meng, Shu; Fan, Yuqi; Chen, Ting; Cao, Jiatian; Jiang, Rujia; Wang, Changqian

    2011-02-01

    Several kinds of sesquiterpene lactones have been proven to inhibit NF-κB and to retard atherosclerosis by reducing lesion size and changing plaque composition. The anti-malarial artemisinin (Art) is a pure sesquiterpene lactone extracted from the Chinese herb Artemisia annua (qinghao, sweet wormwood). In the present study, we demonstrate that artemisinin inhibits the secretion and the mRNA levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6 in a dose-dependent manner in phorbol 12-myristate 13-acetate (PMA)-induced THP-1 human monocytes. We also found that the NF-κB specific inhibitor, Bay 11-7082, inhibited the expression of these pro-inflammatory cytokines, suggesting that the NF-κB pathway may be involved in the decreased cytokine release. At all time-points (1-6 h), artemisinin impeded the phosphorylation of IKKα/ß, the phosphorylation and degradation of IκBα and the nuclear translocation of the NF-κB p65 subunit. Additionally, artemisinin inhibited the translocation of the NF-κB p65 subunit as demonstrated by confocal laser scanning microscopic analysis and by NF-κB binding assays. Our data indicate that artemisinin exerts an anti-inflammatory effect on PMA-induced THP-1 monocytes, suggesting the potential role of artemisinin in preventing the inflammatory progression of atherosclerosis.

  20. 3D structure and immunogenicity of Plasmodium falciparum sporozoite induced associated protein peptides as components of fully-protective anti-malarial vaccine.

    PubMed

    Alba, Martha P; Almonacid, Hannia; Calderón, Dayana; Chacón, Edgar A; Poloche, Luis A; Patarroyo, Manuel A; Patarroyo, Manuel E

    2011-12-16

    SIAP-1 and SIAP-2 are proteins which are implicated in early events involving Plasmodium falciparum infection of the Anopheles mosquito vector and the human host. High affinity HeLa and HepG2 cell binding conserved peptides have been previously identified in these proteins, i.e. SIAP-1 34893 ((421)KVQGLSYLLRRKNGTKHPVY(440)) and SIAP-1 34899 ((541)YVLNSKLLNSRSFDKFKWIQ(560)) and SIAP-2 36879 ((181)LLLYSTNSEDNLDISFGELQ(200)). When amino acid sequences have been properly modified (replacements shown in bold) they have induced high antibody titres against sporozoites in Aotus monkeys (assessed by IFA) and in the corresponding recombinant proteins (determined by ELISA and Western blot). (1)H NMR studies of these conserved native and modified high activity binding peptides (HABPs) revealed that all had α-helical structures in different locations and lengths. Conserved and corresponding modified HABPs displayed different lengths between the residues fitting into MHCII molecule pockets 1-9 and different amino acid orientation based on their different HLA-DRβ1(∗) binding motifs and binding registers, suggesting that such modifications were associated with making them immunogenic. The results suggested that these modified HAPBs could be potential targets for inclusion as components of a fully-effective, minimal sub-unit based, multi-epitope, and multistage anti-malarial vaccine.

  1. Effect of external stress on density and size of glandular trichomes in full-grown Artemisia annua, the source of anti-malarial artemisinin

    PubMed Central

    Kjær, Anders; Grevsen, Kai; Jensen, Martin

    2012-01-01

    Background and aims Glandular trichomes (GT) of Artemisia annua produce valuable compounds for pharmaceutical and industrial uses, most notably the anti-malarial artemisinin. Our aim was to find out whether the density, number and size of GT can be manipulated to advantage by environmental stress. A range of external stress treatments, including stress response regulators, was therefore given to fully grown plants under field and greenhouse conditions. Methodology In a field experiment (Ex1), seed-grown plants were subjected to chemical or physical stress and plants analysed after 5 weeks. In a greenhouse experiment (Ex2), three groups of clonally derived plants were stressed at weekly intervals for 5 weeks. Stress treatments included sandblasting, leaf cutting and spraying with jasmonic acid, salicylic acid, chitosan oligosaccharide (COS), H2O2 (HP) and NaCl (SC)at different concentrations. Leaves from an upper and a lower position on the plants were analysed by fluorescence microscopy to determine the density and size of GT. Principal results Densities of GT on upper leaves of full-grown A. annua plants generally showed no response to external stress and only plants from one clone of Ex2 supported the hypothesis that increased density of GT was inducible in upper leaves by stress (significant for SC, HP and COS). The density of GT on lower leaves was not affected by stress in any experiment. Glandular trichomes were significantly smaller on the lower leaves in response to stress in Ex2, and a similar non-significant trend was observed in Ex1. Conclusions The results indicate a dynamic system in which stress treatments of large A. annua plants had a minor promoting effect on the initiation of GT in developing leaves, and a maturing effect of GT later in the lifetime of the individual GT. The hypothesis that applying stress can induce larger GT or more numerous GT was rejected. PMID:22833781

  2. Use of a colorimetric (DELI) test for the evaluation of chemoresistance of Plasmodium falciparum and Plasmodium vivax to commonly used anti-plasmodial drugs in the Brazilian Amazon

    PubMed Central

    2013-01-01

    Background The emergence and spread of Plasmodium falciparum and Plasmodium vivax resistance to available anti-malarial drugs represents a major drawback in the control of malaria and its associated morbidity and mortality. The aim of this study was to evaluate the chemoresistance profile of P. falciparum and P. vivax to commonly used anti-plasmodial drugs in a malaria-endemic area in the Brazilian Amazon. Methods The study was carried out in Manaus (Amazonas state), in the Brazilian Amazon. A total of 88 P. falciparum and 178 P. vivax isolates was collected from 2004 to 2007. The sensitivity of P. falciparum isolates was determined to chloroquine, quinine, mefloquine and artesunate and the sensitivity of P. vivax isolates was determined to chloroquine and mefloquine, by using the colorimetric DELI test. Results As expected, a high prevalence of P. falciparum isolates resistant to chloroquine (78.1%) was observed. The prevalence of isolates with profile of resistance or decreased sensitivity for quinine, mefloquine and artesunate was 12.7, 21.2 and 11.7%, respectively. In the case of P. vivax, the prevalence of isolates with profile of resistance for chloroquine and mefloquine was 9.8 and 28%, respectively. No differences in the frequencies of isolates with profile of resistance or geometric mean IC50s were seen when comparing the data obtained in 2004, 2005, 2006 and 2007, for all tested anti-malarials. Conclusions The great majority of P. falciparum isolates in the Brazilian malaria-endemic area remain resistant to chloroquine, and the decreased sensitivity to quinine, mefloquine and artesunate observed in 10–20% of the isolates must be taken with concern, especially for artesunate. Plasmodium vivax isolates also showed a significant proportion of isolates with decreased sensitivity to chloroquine (first-line drug) and mainly to mefloquine. The data presented here also confirm the usefulness of the DELI test to generate results able to impact on public health

  3. Communicating the AMFm message: exploring the effect of communication and training interventions on private for-profit provider awareness and knowledge related to a multi-country anti-malarial subsidy intervention

    PubMed Central

    2014-01-01

    Background The Affordable Medicines Facility - malaria (AMFm), implemented at national scale in eight African countries or territories, subsidized quality-assured artemisinin combination therapy (ACT) and included communication campaigns to support implementation and promote appropriate anti-malarial use. This paper reports private for-profit provider awareness of key features of the AMFm programme, and changes in provider knowledge of appropriate malaria treatment. Methods This study had a non-experimental design based on nationally representative surveys of outlets stocking anti-malarials before (2009/10) and after (2011) the AMFm roll-out. Results Based on data from over 19,500 outlets, results show that in four of eight settings, where communication campaigns were implemented for 5–9 months, 76%-94% awareness of the AMFm ‘green leaf’ logo, 57%-74% awareness of the ACT subsidy programme, and 52%-80% awareness of the correct recommended retail price (RRP) of subsidized ACT were recorded. However, in the remaining four settings where communication campaigns were implemented for three months or less, levels were substantially lower. In six of eight settings, increases of at least 10 percentage points in private for-profit providers’ knowledge of the correct first-line treatment for uncomplicated malaria were seen; and in three of these the levels of knowledge achieved at endline were over 80%. Conclusions The results support the interpretation that, in addition to the availability of subsidized ACT, the intensity of communication campaigns may have contributed to the reported levels of AMFm-related awareness and knowledge among private for-profit providers. Future subsidy programmes for anti-malarials or other treatments should similarly include communication activities. PMID:24495691

  4. Temperature-sensitive polymers for drug delivery.

    PubMed

    Fitzpatrick, Scott D; Fitzpatrick, Lindsay E; Thakur, Ajit; Mazumder, Mohammad A Jafar; Sheardown, Heather

    2012-07-01

    The ability to undergo rapid changes in response to subtle environmental cues make stimuli- responsive materials attractive candidates for minimally invasive, targeted and personalized drug delivery applications. This special report aims to highlight and provide a brief description of several of the significant natural and synthetic temperature-responsive materials that have clinical relevance for drug delivery applications. This report examines the advantages and disadvantages of natural versus synthetic materials and outlines various scaffold architectures that can be utilized with temperature-sensitive drug delivery materials. The authors provide a commentary on the current state of the field and provide their insight into future expectations for temperature-sensitive drug delivery, emphasizing the importance of the emergence of dual and multiresponsive systems capable of responding precisely to an expanding set of stimuli, thereby allowing the development of disease-specific drug delivery vehicles.

  5. Light-sensitive intelligent drug delivery systems.

    PubMed

    Alvarez-Lorenzo, Carmen; Bromberg, Lev; Concheiro, Angel

    2009-01-01

    Drug delivery systems (DDS) capable of releasing an active molecule at the appropriate site and at a rate that adjusts in response to the progression of the disease or to certain functions/biorhythms of the organism are particularly appealing. Biocompatible materials sensitive to certain physiological variables or external physicochemical stimuli (intelligent materials) can be used for achieving this aim. Light-responsiveness is receiving increasing attention owing to the possibility of developing materials sensitive to innocuous electromagnetic radiation (mainly in the UV, visible and near-infrared range), which can be applied on demand at well delimited sites of the body. Some light-responsive DDS are of a single use (i.e. the light triggers an irreversible structural change that provokes the delivery of the entire dose) while others able to undergo reversible structural changes when cycles of light/dark are applied, behave as multi-switchable carriers (releasing the drug in a pulsatile manner). In this review, the mechanisms used to develop polymeric micelles, gels, liposomes and nanocomposites with light-sensitiveness are analyzed. Examples of the capability of some polymeric, lipidic and inorganic structures to regulate the release of small solutes and biomacromolecules are presented and the potential of light-sensitive carriers as functional components of intelligent DDS is discussed.

  6. Characterization of two malaria parasite organelle translation elongation factor G proteins: the likely targets of the anti-malarial fusidic acid.

    PubMed

    Johnson, Russell A; McFadden, Geoffrey I; Goodman, Christopher D

    2011-01-01

    Malaria parasites harbour two organelles with bacteria-like metabolic processes that are the targets of many anti-bacterial drugs. One such drug is fusidic acid, which inhibits the translation component elongation factor G. The response of P. falciparum to fusidic acid was characterised using extended SYBR-Green based drug trials. This revealed that fusidic acid kills in vitro cultured P. falciparum parasites by immediately blocking parasite development. Two bacterial-type protein translation elongation factor G genes are identified as likely targets of fusidic acid. Sequence analysis suggests that these proteins function in the mitochondria and apicoplast and both should be sensitive to fusidic acid. Microscopic examination of protein-reporter fusions confirm the prediction that one elongation factor G is a component of parasite mitochondria whereas the second is a component of the relict plastid or apicoplast. The presence of two putative targets for a single inhibitory compound emphasizes the potential of elongation factor G as a drug target in malaria.

  7. Evaluation of the QT effect of a combination of piperaquine and a novel anti-malarial drug candidate OZ439, for the treatment of uncomplicated malaria

    PubMed Central

    Darpo, Borje; Ferber, Georg; Siegl, Peter; Laurijssens, Bart; Macintyre, Fiona; Toovey, Stephen; Duparc, Stephan

    2015-01-01

    Aims The aim was to investigate the QT effect of a single dose combination regimen of piperaquine phosphate (PQP) and a novel aromatic trioxolane, OZ439, for malaria treatment. Methods Exposure–response (ER) analysis was performed on data from a placebo-controlled, single dose, study with OZ439 and PQP. Fifty-nine healthy subjects aged 18 to 55 years received OZ439 alone or placebo in a first period, followed by OZ439 plus PQP or matching placebos in period 2. OZ439 and PQP doses ranged from 100–800 mg and 160–1440 mg, respectively. Twelve-lead ECG tracings and PK samples were collected serially pre- and post-dosing. Results A significant relation between plasma concentrations and placebo-corrected change from baseline QTcF (ΔΔQTcF) was demonstrated for piperaquine, but not for OZ439, with a mean slope of 0.047 ms per ng ml−1 (90% CI 0.038, 0.057). Using an ER model that accounts for plasma concentrations of both piperaquine and OZ439, a largest mean QTcF effect of 14 ms (90% CI 10, 18 ms) and 18 ms (90% CI 14, 22 ms) was predicted at expected plasma concentrations of a single dose 800 mg OZ439 combined with PQP 960 mg (188 ng ml−1) and 1440 mg (281 ng ml−1), respectively, administered in the fasted state. Conclusions Piperaquine prolongs the QTc interval in a concentration-dependent way. A single dose regimen combining 800 mg OZ439 with 960 mg or 1440 mg PQP is expected to result in lower peak piperaquine plasma concentrations compared with available 3 day PQP-artemisinin combinations and can therefore be predicted to cause less QTc prolongation. PMID:25966781

  8. Direct comparison of the histidine-rich protein-2 enzyme-linked immunosorbent assay (HRP-2 ELISA) and malaria SYBR green I fluorescence (MSF) drug sensitivity tests in Plasmodium falciparum reference clones and fresh ex vivo field isolates from Cambodia

    PubMed Central

    2013-01-01

    Background Performance of the histidine-rich protein-2 enzyme-linked immunosorbent assay (HRP-2 ELISA) and malaria SYBR Green I fluorescence (MSF) drug sensitivity tests were directly compared using Plasmodium falciparum reference strains and fresh ex vivo isolates from Cambodia against a panel of standard anti-malarials. The objective was to determine which of these two common assays is more appropriate for studying drug susceptibility of “immediate ex vivo” (IEV) isolates, analysed without culture adaption, in a region of relatively low malaria transmission. Methods Using the HRP-2 and MSF methods, the 50% inhibitory concentration (IC50) values against a panel of malaria drugs were determined for P. falciparum reference clones (W2, D6, 3D7 and K1) and 41 IEV clinical isolates from an area of multidrug resistance in Cambodia. Comparison of the IC50 values from the two methods was made using Wilcoxon matched pair tests and Pearson’s correlation. The lower limit of parasitaemia detection for both methods was determined for reference clones and IEV isolates. Since human white blood cell (WBC) DNA in clinical samples is known to reduce MSF assay sensitivity, SYBR Green I fluorescence linearity of P. falciparum samples spiked with WBCs was evaluated to assess the relative degree to which MSF sensitivity is reduced in clinical samples. Results IC50 values correlated well between the HRP-2 and MSF methods when testing either P. falciparum reference clones or IEV isolates against 4-aminoquinolines (chloroquine, piperaquine and quinine) and the quinoline methanol mefloquine (Pearson r = 0.85-0.99 for reference clones and 0.56-0.84 for IEV isolates), whereas a weaker IC50 value correlation between methods was noted when testing artemisinins against reference clones and lack of correlation when testing IEV isolates. The HRP-2 ELISA produced a higher overall success rate (90% for producing IC50 best-fit sigmoidal curves), relative to only a 40% success rate for the

  9. Integrating heterogeneous drug sensitivity data from cancer pharmacogenomic studies

    PubMed Central

    Pozdeyev, Nikita; Yoo, Minjae; Mackie, Ryan; Schweppe, Rebecca E.; Tan, Aik Choon; Haugen, Bryan R.

    2016-01-01

    The consistency of in vitro drug sensitivity data is of key importance for cancer pharmacogenomics. Previous attempts to correlate drug sensitivities from the large pharmacogenomics databases, such as the Cancer Cell Line Encyclopedia (CCLE) and the Genomics of Drug Sensitivity in Cancer (GDSC), have produced discordant results. We developed a new drug sensitivity metric, the area under the dose response curve adjusted for the range of tested drug concentrations, which allows integration of heterogeneous drug sensitivity data from the CCLE, the GDSC, and the Cancer Therapeutics Response Portal (CTRP). We show that there is moderate to good agreement of drug sensitivity data for many targeted therapies, particularly kinase inhibitors. The results of this largest cancer cell line drug sensitivity data analysis to date are accessible through the online portal, which serves as a platform for high power pharmacogenomics analysis. PMID:27322211

  10. Crystallization, X-Ray Structure Determination and Structure-Based Drug Design for Targeted Malarial Enzymes

    DTIC Science & Technology

    1998-07-01

    COOPERATIVE AGREEMENT NUMBER DAMD17-95-2-5007 TITLE: Crystallization, X-ray Structure Determination and Structure-Based Drug Design for...approach for the develpment of anti-malarial agent using structure-based drug design . This technique will enable us to identify active site inhibitors...based drug design project high resolution three domensional structure of the enzyme - inhibitor complex provides the basis for further modifications

  11. Using Click Chemistry to Identify Potential Drug Targets in Plasmodium

    DTIC Science & Technology

    2016-06-01

    the Plasmodium mammalian cycle . Identifying parasite proteins that are required for liver infection can lead to novel drugs against malaria. For the...mammalian cycle . Inhibiting this step can block malaria at an early step. However, few anti-malarials target liver infection by sporozoites. Our goal is...methods to synthesize TSP and TSP derivatives, we demonstrated that we could append a propargyl group to the piperidine ring nitrogen and that this

  12. Sensitive radioenzymatic assay for catechol drugs

    SciTech Connect

    Durrett, L.R.; Ziegler, M.G.

    1980-01-01

    This assay measures picogram quantities of catechol drugs and endogenous catecholamines in body tissues and fluids. The catechols are converted to their 3H-O-methyl metabolites during incubation with 3H-S-adenosylmethionine then separated by solvent extraction and thin-layer chromatography. Most drugs containing the catechol structure can be radiolabeled and separated from norepinephrine and epinephrine by this technique to provide simultaneous measurement of endogenous and exogenously administered catechols. The disposition of isoproterenol in tissues and fluids of man and experimental animals is measured to illustrate the utility of this assay. The reactivity of several commonly administered catechol drugs with COMT is described and the possible implications discussed.

  13. Conditioned and sensitized responses to stimulant drugs in humans.

    PubMed

    Leyton, Marco

    2007-11-15

    In animal models considerable evidence suggests that increased motivation to seek and ingest drugs of abuse are related to conditioned and sensitized activations of the mesolimbic dopamine (DA) system. Direct evidence for these phenomena in humans, though, is sparse. However, recent studies support the following. First, the acute administration of drugs of abuse across pharmacological classes increases extracellular DA levels within the human ventral striatum. Second, individual differences in the magnitude of this response correlate with rewarding effects of the drugs and the personality trait of novelty seeking. Third, transiently diminishing DA transmission in humans decreases drug craving, the propensity to preferentially respond to reward-paired stimuli, and the ability to sustain responding for future drug reward. Finally, very recent studies suggest that repeated exposure to stimulant drugs, either on the street or in the laboratory, can lead to conditioned and sensitized behavioral responses and DA release. In contrast to these findings, though, in individuals with a long history of substance abuse, drug-induced DA release is decreased. This diminished DA release could reflect two different phenomena. First, it is possible that drug withdrawal related decrements in DA cell function persist longer than previously suspected. Second, drug-paired stimuli may gain marked conditioned control over the release of DA and the expression of sensitization leading to reduced DA release when drug-related cues are absent. Based on these observations a two-factor hypothesis of the role of DA in drug abuse is proposed. In the presence of drug cues, conditioned and sensitized DA release would occur leading to focused drug-seeking behavior. In comparison, in the absence of drug-related stimuli DA function would be reduced, diminishing the ability of individuals to sustain goal-directed behavior and long-term objectives. This conditioned control of the expression of sensitized

  14. Population genetics and drug resistance markers: an essential for malaria surveillance in Pakistan.

    PubMed

    Raza, Afsheen; Beg, Mohammad Asim

    2013-12-01

    Plasmodium (P.) vivax is the prevalent malarial species accounting for 70% of malaria cases in Pakistan. However, baseline epidemiological data on P. vivax population structure and drug resistance are lacking from Pakistan. For population structure studies, molecular genetic markers, circumsporozoite protein (csp) and merozoite surface protein-1 (msp-1) are considered useful as these play an important role in P. vivax survival under immune and environmental pressure. Furthermore, these genes have also been identified as suitable candidates for vaccine development. While efforts for effective vaccine are underway, anti-malarial agents remain the mainstay for control. Evidence of resistance against commonly used anti-malarial agents, particularly Sulphadoxine-Pyrimethamine (SP) is threatening to make this form of control defunct. Therefore, studies on drug resistance are necessary so that anti-malarial treatment strategies can be structured and implemented accordingly by the Malaria Control Program, Pakistan. This review aims to provide information on genetic markers of P. vivax population structure and drug resistance and comment on their usefulness in molecular surveillance and control.

  15. Methods to Increase the Sensitivity of High Resolution Melting Single Nucleotide Polymorphism Genotyping in Malaria.

    PubMed

    Daniels, Rachel; Hamilton, Elizabeth J; Durfee, Katelyn; Ndiaye, Daouda; Wirth, Dyann F; Hartl, Daniel L; Volkman, Sarah K

    2015-11-10

    Despite decades of eradication efforts, malaria remains a global burden. Recent renewed interest in regional elimination and global eradication has been accompanied by increased genomic information about Plasmodium parasite species responsible for malaria, including characteristics of geographical populations as well as variations associated with reduced susceptibility to anti-malarial drugs. One common genetic variation, single-nucleotide polymorphisms (SNPs), offers attractive targets for parasite genotyping. These markers are useful not only for tracking drug resistance markers but also for tracking parasite populations using markers not under drug or other selective pressures. SNP genotyping methods offer the ability to track drug resistance as well as to fingerprint individual parasites for population surveillance, particularly in response to malaria control efforts in regions nearing elimination status. While informative SNPs have been identified that are agnostic to specific genotyping technologies, high-resolution melting (HRM) analysis is particularly suited to field-based studies. Compared to standard fluorescent-probe based methods that require individual SNPs in a single labeled probe and offer at best 10% sensitivity to detect SNPs in samples that contain multiple genomes (polygenomic), HRM offers 2-5% sensitivity. Modifications to HRM, such as blocked probes and asymmetric primer concentrations as well as optimization of amplification annealing temperatures to bias PCR towards amplification of the minor allele, further increase the sensitivity of HRM. While the sensitivity improvement depends on the specific assay, we have increased detection sensitivities to less than 1% of the minor allele. In regions approaching malaria eradication, early detection of emerging or imported drug resistance is essential for prompt response. Similarly, the ability to detect polygenomic infections and differentiate imported parasite types from cryptic local reservoirs

  16. Visual contrast sensitivity in drug-induced Parkinsonism.

    PubMed Central

    Bulens, C; Meerwaldt, J D; van der Wildt, G J; Keemink, C J

    1989-01-01

    The influence of stimulus orientation on contrast sensitivity function was studied in 10 patients with drug-induced Parkinsonism. Nine of the 10 patients had at least one eye with contrast sensitivity deficit for vertical and/or horizontal stimuli. Only generalised contrast sensitivity loss, observed in two eyes, was stimulus orientation independent. All spatial frequency-selective contrast deficits in 15 eyes were orientation dependent. The striking similarity between the pattern of contrast sensitivity loss in drug-induced Parkinsonism and that in idiopathic Parkinson's disease, suggests that generalised dopaminergic deficiency, from whatever cause, affects visual function in an analogous way. PMID:2926418

  17. Visual contrast sensitivity in drug-induced Parkinsonism.

    PubMed

    Bulens, C; Meerwaldt, J D; van der Wildt, G J; Keemink, C J

    1989-03-01

    The influence of stimulus orientation on contrast sensitivity function was studied in 10 patients with drug-induced Parkinsonism. Nine of the 10 patients had at least one eye with contrast sensitivity deficit for vertical and/or horizontal stimuli. Only generalised contrast sensitivity loss, observed in two eyes, was stimulus orientation independent. All spatial frequency-selective contrast deficits in 15 eyes were orientation dependent. The striking similarity between the pattern of contrast sensitivity loss in drug-induced Parkinsonism and that in idiopathic Parkinson's disease, suggests that generalised dopaminergic deficiency, from whatever cause, affects visual function in an analogous way.

  18. Gene sensitizes cancer cells to chemotherapy drugs

    Cancer.gov

    NCI scientists have found that a gene, Schlafen-11 (SLFN11), sensitizes cells to substances known to cause irreparable damage to DNA.  As part of their study, the researchers used a repository of 60 cell types to identify predictors of cancer cell respons

  19. Glycosides as possible lead antimalarial in new drug discovery: future perspectives.

    PubMed

    Marya; Khan, Haroon; Ahmad, Izhar

    2017-01-15

    Malaria remains one of the major public health problems worldwide and is responsible for a large number of morbidity and mortality. Especially, in the third world countries, it is still alarming. The development of drug-resistant to Plasmodium falciparum strains has further degraded the overall situation. However, a limited number of effective drugs available emphasizes how essential it is to establish new anti-malarial compounds. New antimalarial agents with distinctive structures and mechanism of action from the natural origin are thus immediately required to treat sensitive and drug-resistant strains of malaria. over the years, phytopharmaceuticals have provided numerous lead compounds. Similarly, the success rate of botanicals in terms of clinical significance is also very high. Of them, glycosides is one of the most widely distributed and emerging class of plant secondary metabolites. This review provides an outlook to recently isolated glycosides from plants with marked antimalarial effects in an in-vitro and in-vivo protocols and thus ideal candidates for clinical trials to ascertain their clinical utility and or led compounds.

  20. Virtual screen for repurposing approved and experimental drugs for candidate inhibitors of EBOLA virus infection

    PubMed Central

    Veljkovic, Veljko; Loiseau, Philippe M.; Figadere, Bruno; Glisic, Sanja; Veljkovic, Nevena; Perovic, Vladimir R.; Cavanaugh, David P.; Branch, Donald R.

    2015-01-01

    The ongoing Ebola virus epidemic has presented numerous challenges with respect to control and treatment because there are no approved drugs or vaccines for the Ebola virus disease (EVD). Herein is proposed simple theoretical criterion for fast virtual screening of molecular libraries for candidate inhibitors of Ebola virus infection. We performed a repurposing screen of 6438 drugs from DrugBank using this criterion and selected 267 approved and 382 experimental drugs as candidates for treatment of EVD including 15 anti-malarial drugs and 32 antibiotics. An open source Web server allowing screening of molecular libraries for candidate drugs for treatment of EVD was also established. PMID:25717373

  1. Multifunctional, stimuli-sensitive nanoparticulate systems for drug delivery

    PubMed Central

    Torchilin, Vladimir P.

    2015-01-01

    The use of nanoparticulate pharmaceutical drug delivery systems (NDDSs) to enhance the in vivo effectiveness of drugs is now well established. The development of multifunctional and stimulus-sensitive NDDSs is an active area of current research. Such NDDSs can have long circulation times, target the site of the disease and enhance the intracellular delivery of a drug. This type of NDDS can also respond to local stimuli that are characteristic of the pathological site by, for example, releasing an entrapped drug or shedding a protective coating, thus facilitating the interaction between drug-loaded nanocarriers and target cells or tissues. In addition, imaging contrast moieties can be attached to these carriers to track their real-time biodistribution and accumulation in target cells or tissues. Here, I highlight recent developments with multifunctional and stimuli-sensitive NDDSs and their therapeutic potential for diseases including cancer, cardiovascular diseases and infectious diseases. PMID:25287120

  2. Multitask learning improves prediction of cancer drug sensitivity

    PubMed Central

    Yuan, Han; Paskov, Ivan; Paskov, Hristo; González, Alvaro J.; Leslie, Christina S.

    2016-01-01

    Precision oncology seeks to predict the best therapeutic option for individual patients based on the molecular characteristics of their tumors. To assess the preclinical feasibility of drug sensitivity prediction, several studies have measured drug responses for cytotoxic and targeted therapies across large collections of genomically and transcriptomically characterized cancer cell lines and trained predictive models using standard methods like elastic net regression. Here we use existing drug response data sets to demonstrate that multitask learning across drugs strongly improves the accuracy and interpretability of drug prediction models. Our method uses trace norm regularization with a highly efficient ADMM (alternating direction method of multipliers) optimization algorithm that readily scales to large data sets. We anticipate that our approach will enhance efforts to exploit growing drug response compendia in order to advance personalized therapy. PMID:27550087

  3. Stimuli sensitive hydrogels for ophthalmic drug delivery: A review.

    PubMed

    Kushwaha, Swatantra Ks; Saxena, Prachi; Rai, Ak

    2012-04-01

    Amongst the various routes of drug delivery, the field of ocular drug delivery is one of the most interesting and challenging endeavors facing the pharmaceutical scientist for past 10-20 years. As an isolated organ, eye is very difficult to study from a drug delivery point of view. Despite this limitation, improvements have been made with the objective of maintaining the drug in the biophase for an extended period. A major problem in ocular therapeutics is the attainment of an optimal drug concentration at the site of action. To achieve effective ophthalmic therapy, an adequate amount of active ingredient must be delivered and maintained within the eye. The most frequently used dosage forms, i.e., eye solution, eye ointments, eye gels, and eye suspensions are compromised in their effectiveness by several limitations leading to poor ocular bioavailability. Ophthalmic use of viscosity-enhancing agents, penetration enhancers, cyclodextrins, prodrug approaches, and ocular inserts, and the ready existing drug carrier systems along with their application to ophthalmic drug delivery are common to improve ocular bioavailability. Amongst these hydrogel (stimuli sensitive) systems are important, which undergo reversible volume and/or sol-gel phase transitions in response to physiological (temperature, pH and present of ions in organism fluids, enzyme substrate) or other external (electric current, light) stimuli. They help to increase in precorneal residence time of drug to a sufficient extent that an ocularly delivered drug can exhibit its maximum biological action. The concept of this innovative ophthalmic delivery approach is to decrease the systemic side effects and to create a more pronounced effect with lower doses of the drug. The present article describes the advantages and use stimuli sensitive of hydrogel systems in ophthalmic drug delivery.

  4. Stimuli sensitive hydrogels for ophthalmic drug delivery: A review

    PubMed Central

    Kushwaha, Swatantra KS; Saxena, Prachi; Rai, AK

    2012-01-01

    Amongst the various routes of drug delivery, the field of ocular drug delivery is one of the most interesting and challenging endeavors facing the pharmaceutical scientist for past 10-20 years. As an isolated organ, eye is very difficult to study from a drug delivery point of view. Despite this limitation, improvements have been made with the objective of maintaining the drug in the biophase for an extended period. A major problem in ocular therapeutics is the attainment of an optimal drug concentration at the site of action. To achieve effective ophthalmic therapy, an adequate amount of active ingredient must be delivered and maintained within the eye. The most frequently used dosage forms, i.e., eye solution, eye ointments, eye gels, and eye suspensions are compromised in their effectiveness by several limitations leading to poor ocular bioavailability. Ophthalmic use of viscosity-enhancing agents, penetration enhancers, cyclodextrins, prodrug approaches, and ocular inserts, and the ready existing drug carrier systems along with their application to ophthalmic drug delivery are common to improve ocular bioavailability. Amongst these hydrogel (stimuli sensitive) systems are important, which undergo reversible volume and/or sol-gel phase transitions in response to physiological (temperature, pH and present of ions in organism fluids, enzyme substrate) or other external (electric current, light) stimuli. They help to increase in precorneal residence time of drug to a sufficient extent that an ocularly delivered drug can exhibit its maximum biological action. The concept of this innovative ophthalmic delivery approach is to decrease the systemic side effects and to create a more pronounced effect with lower doses of the drug. The present article describes the advantages and use stimuli sensitive of hydrogel systems in ophthalmic drug delivery. PMID:23119233

  5. Improving Drug Sensitivity Prediction Using Different Types of Data

    PubMed Central

    Hejase, HA; Chan, C

    2015-01-01

    The algorithms and models used to address the two subchallenges that are part of the NCI-DREAM (Dialogue for Reverse Engineering Assessments and Methods) Drug Sensitivity Prediction Challenge (2012) are presented. In subchallenge 1, a bidirectional search algorithm is introduced and optimized using an ensemble scheme and a nonlinear support vector machine (SVM) is then applied to predict the effects of the drug compounds on breast cancer cell lines. In subchallenge 2, a weighted Euclidean distance method is introduced to predict and rank the drug combinations from the most to the least effective in reducing the viability of a diffuse large B-cell lymphoma (DLBCL) cell line. PMID:26225231

  6. First evidence that drugs of abuse produce behavioral sensitization and cross sensitization in planarians.

    PubMed

    Rawls, Scott M; Patil, Tavni; Yuvasheva, Ekaternia; Raffa, Robert B

    2010-07-01

    Behavioral sensitization in mammals, including humans, is sensitive to factors such as administration route, testing environment, and pharmacokinetic confounds, unrelated to the drugs themselves that are difficult to eliminate. Simpler animals less susceptible to these confounding influences may be advantageous substitutes for studying sensitization. We tested this hypothesis by determining whether planarians display sensitization and cross sensitization to cocaine and glutamate. Planarian hyperactivity was quantified as the number of C-like hyperkinesias during a 1-min drug exposure. Planarians exposed initially to cocaine (or glutamate) on day 1 were challenged with cocaine (or glutamate) after 2 or 6 days of abstinence. Acute cocaine or glutamate produced concentration-related hyperactivity. Cocaine or glutamate challenge after 2 and 6 days of abstinence enhanced the hyperactivity, indicating the substances produced planarian behavioral sensitization. Cross-sensitization experiments showed that cocaine produced greater hyperactivity in planarians earlier exposed to glutamate than in glutamate-naive planarians, and vice versa. Behavioral responses were pharmacologically selective because neither scopolamine nor caffeine produced planarian behavioral sensitization despite causing hyperactivity after initial administration, and acute gamma-aminobutyric acid did not cause hyperactivity. Demonstration of pharmacologically selective behavioral sensitization in planarians suggests that these flatworms represent a sensitive in-vivo model to study cocaine behavioral sensitization and to screen potential abuse-deterrent therapeutics.

  7. Plasmodium falciparum Transfected with Ultra Bright NanoLuc Luciferase Offers High Sensitivity Detection for the Screening of Growth and Cellular Trafficking Inhibitors

    PubMed Central

    Elsworth, Brendan; Charnaud, Sarah C.; Sanders, Paul R.; Crabb, Brendan S.; Gilson, Paul R.

    2014-01-01

    Drug discovery is a key part of malaria control and eradication strategies, and could benefit from sensitive and affordable assays to quantify parasite growth and to help identify the targets of potential anti-malarial compounds. Bioluminescence, achieved through expression of exogenous luciferases, is a powerful tool that has been applied in studies of several aspects of parasite biology and high throughput growth assays. We have expressed the new reporter NanoLuc (Nluc) luciferase in Plasmodium falciparum and showed it is at least 100 times brighter than the commonly used firefly luciferase. Nluc brightness was explored as a means to achieve a growth assay with higher sensitivity and lower cost. In addition we attempted to develop other screening assays that may help interrogate libraries of inhibitory compounds for their mechanism of action. To this end parasites were engineered to express Nluc in the cytoplasm, the parasitophorous vacuole that surrounds the intraerythrocytic parasite or exported to the red blood cell cytosol. As proof-of-concept, these parasites were used to develop functional screening assays for quantifying the effects of Brefeldin A, an inhibitor of protein secretion, and Furosemide, an inhibitor of new permeation pathways used by parasites to acquire plasma nutrients. PMID:25392998

  8. Crosslinked ionic polysaccharides for stimuli-sensitive drug delivery.

    PubMed

    Alvarez-Lorenzo, Carmen; Blanco-Fernandez, Barbara; Puga, Ana M; Concheiro, Angel

    2013-08-01

    Polysaccharides are gaining increasing attention as components of stimuli-responsive drug delivery systems, particularly since they can be obtained in a well characterized and reproducible way from the natural sources. Ionic polysaccharides can be readily crosslinked to render hydrogel networks sensitive to a variety of internal and external variables, and thus suitable for switching drug release on-off through diverse mechanisms. Hybrids, composites and grafted polymers can reinforce the responsiveness and widen the range of stimuli to which polysaccharide-based systems can respond. This review analyzes the state of the art of crosslinked ionic polysaccharides as components of delivery systems that can regulate drug release as a function of changes in pH, ion nature and concentration, electric and magnetic field intensity, light wavelength, temperature, redox potential, and certain molecules (enzymes, illness markers, and so on). Examples of specific applications are provided. The information compiled demonstrates that crosslinked networks of ionic polysaccharides are suitable building blocks for developing advanced externally activated and feed-back modulated drug delivery systems.

  9. Targeting drug sensitivity predictors: New potential strategies to improve pharmacotherapy of human brain disorders.

    PubMed

    Kalueff, Allan V; Stewart, Adam Michael; Nguyen, Michael; Song, Cai; Gottesman, Irving I

    2015-12-03

    One of the main challenges in medicine is the lack of efficient drug therapies for common human disorders. For example, although depressed patients receive powerful antidepressants, many often remain resistant to psychopharmacotherapy. The growing recognition of complex interplay between the drug targets and the predictors of drug sensitivity requires an improved understanding of these two key aspects of drug action and their potentially shared molecular networks. Here, we apply the concept of endophenotypes and their interplay to drug action and sensitivity. Based on these analyses, we postulate that novel drugs may be developed by targeting specific molecular pathways that integrate drug targets with drug sensitivity predictors.

  10. Drug Sensitivity in Older Adults: The Role of Physiologic and Pharmacokinetic Factors.

    ERIC Educational Resources Information Center

    Cherry, Katie E.; Morton, Mark R.

    1989-01-01

    Notes that age-related changes in physiology and pharmacokinetics (how drugs are used in the body) lead to increased drug sensitivity and potentially harmful drug effects. Addresses heightened sensitivity to drug effects seen in older adults. Presents three examples of physiologic decline and discusses some broad considerations for geriatric…

  11. Numerical modeling of the transmission dynamics of drug-sensitive and drug-resistant HSV-2

    NASA Astrophysics Data System (ADS)

    Gumel, A. B.

    2001-03-01

    A competitive finite-difference method will be constructed and used to solve a modified deterministic model for the spread of herpes simplex virus type-2 (HSV-2) within a given population. The model monitors the transmission dynamics and control of drug-sensitive and drug-resistant HSV-2. Unlike the fourth-order Runge-Kutta method (RK4), which fails when the discretization parameters exceed certain values, the novel numerical method to be developed in this paper gives convergent results for all parameter values.

  12. Plasmodium falciparum drug resistance in Angola.

    PubMed

    Fançony, Cláudia; Brito, Miguel; Gil, Jose Pedro

    2016-02-09

    Facing chloroquine drug resistance, Angola promptly adopted artemisinin-based combination therapy as the first-line to treat malaria. Currently, the country aims to consolidate malaria control, while preparing for the elimination of the disease, along with others African countries in the region. However, the remarkable capacity of Plasmodium to develop drug resistance represents an alarming threat for those achievements. Herein, the available, but relatively scarce and dispersed, information on malaria drug resistance in Angola, is reviewed and discussed. The review aims to inform but also to encourage future research studies that monitor and update the information on anti-malarial drug efficacy and prevalence of molecular markers of drug resistance, key fields in the context and objectives of elimination.

  13. Photoactive Fluoropolymer Surfaces that Release Sensitizer Drug Molecules

    PubMed Central

    Ghosh, Goutam; Minnis, Mihaela; Ghogare, Ashwini A.; Abramova, Inna; Cengel, Keith; Busch, Theresa M.; Greer, Alexander

    2015-01-01

    We describe a physical-organic study of two fluoropolymers bearing a photoreleasable PEGylated photosensitizer which generates 1O2(1Δg) [chlorin e6 methoxy tri(ethylene glycol) triester]. The surfaces are Teflon/polyvinylalcohol (PVA) nanocomposite and fluorinated silica. The relative efficiency of these surfaces to photorelease the PEGylated sensitizer [shown previously to be phototoxic to ovarian cancer cells (Kimani, S. et al J. Org. Chem 2012, 77, 10638)] was slightly higher for the nanocomposite. In the presence of red light and O2, 1O2 is formed, which cleaves an ethene linkage to liberate the sensitizer in 68–92% yields. The fluoropolymers were designed to deal with multiple problems. Namely, their success relied not only high O2 solubility and drug repellency, but that the C−F bonds physically quench little 1O2 for its productive use away from the surface. The results obtained here indicate that Teflon-like surfaces have potential uses of delivering sensitizer and singlet oxygen for applications in tissue repair and photodynamic therapy (PDT). PMID:25686407

  14. Photoactive fluoropolymer surfaces that release sensitizer drug molecules.

    PubMed

    Ghosh, Goutam; Minnis, Mihaela; Ghogare, Ashwini A; Abramova, Inna; Cengel, Keith A; Busch, Theresa M; Greer, Alexander

    2015-03-12

    We describe a physical-organic study of two fluoropolymers bearing a photoreleasable PEGylated photosensitizer that generates (1)O2((1)Δg) [chlorin e6 methoxy tri(ethylene glycol) triester]. The surfaces are Teflon/poly(vinyl alcohol) (PVA) nanocomposite and fluorinated silica. The relative efficiency of these surfaces to photorelease the PEGylated sensitizer [shown previously to be phototoxic to ovarian cancer cells (Kimani, S. et al. J. Org. Chem 2012, 77, 10638)] was slightly higher for the nanocomposite. In the presence of red light and O2, (1)O2 is formed, which cleaves an ethene linkage to liberate the sensitizer in 68-92% yield. The fluoropolymers were designed to deal with multiple problems. Namely, their success relied not only on high O2 solubility and drug repellency but also on the C-F bonds, which physically quench little (1)O2, for singlet oxygen's productive use away from the surface. The results obtained here indicate that Teflon-like surfaces have potential uses in delivering sensitizer and singlet oxygen for applications in tissue repair and photodynamic therapy (PDT).

  15. Metabolic engineering of E.coli for the production of a precursor to artemisinin, an anti-malarial drug [Chapter 25 in Manual of Industrial Microbiology and Biotechnology, 3rd edition

    SciTech Connect

    Petzold, Christopher; Keasling, Jay

    2011-07-18

    This document is Chapter 25 in the Manual of Industrial Microbiology and Biotechnology, 3rd edition. Topics covered include: Incorporation of Amorpha-4,11-Diene Biosynthetic Pathway into E. coli; Amorpha-4,11-Diene Pathway Optimization; "-Omics" Analyses for Increased Amorpha-4,11-Diene Production; Biosynthetic Oxidation of Amorpha-4,11-Diene.

  16. The effect of carbon nanotubes on drug delivery in an electro-sensitive transdermal drug delivery system.

    PubMed

    Im, Ji S; Bai, Byong Ch; Lee, Young-Seak

    2010-02-01

    An electro-sensitive transdermal drug delivery system was prepared by the electrospinning method to control drug release. A semi-interpenetrating polymer network was prepared as the matrix with polyethylene oxide and pentaerythritol triacrylate polymers. Multi-walled carbon nanotubes were used as an additive to increase the electrical sensitivity. The release experiment was carried out under different electric voltage conditions. Carbon nanotubes were observed in the middle of the electrospun fibers by SEM and TEM. The amount of released drug was effectively increased with higher applied electric voltages. These results were attributed to the excellent electrical conductivity of the carbon additive. The suggested mechanism of drug release involves polyethylene oxide of the semi-interpenetrating polymer network being dissolved under the effects of carbon nanotubes, thereby releasing the drug. The effects of the electro-sensitive transdermal drug delivery system were enhanced by the carbon nanotubes.

  17. New Insight into Isoprenoids Biosynthesis Process and Future Prospects for Drug Designing in Plasmodium

    PubMed Central

    Saggu, Gagandeep S.; Pala, Zarna R.; Garg, Shilpi; Saxena, Vishal

    2016-01-01

    The MEP (Methyl Erythritol Phosphate) isoprenoids biosynthesis pathway is an attractive drug target to combat malaria, due to its uniqueness and indispensability for the parasite. It is functional in the apicoplast of Plasmodium and its products get transported to the cytoplasm, where they participate in glycoprotein synthesis, electron transport chain, tRNA modification and several other biological processes. Several compounds have been tested against the enzymes involved in this pathway and amongst them Fosmidomycin, targeted against IspC (DXP reductoisomerase) enzyme and MMV008138 targeted against IspD enzyme have shown good anti-malarial activity in parasite cultures. Fosmidomycin is now-a-days prescribed clinically, however, less absorption, shorter half-life, and toxicity at higher doses, limits its use as an anti-malarial. The potential of other enzymes of the pathway as candidate drug targets has also been determined. This review details the various drug molecules tested against these targets with special emphasis to Plasmodium. We corroborate that MEP pathway functional within the apicoplast of Plasmodium is a major drug target, especially during erythrocytic stages. However, the major bottlenecks, bioavailability and toxicity of the new molecules needs to be addressed, before considering any new molecule as a potent antimalarial. PMID:27679614

  18. Fear Conditioning Effects on Sensitivity to Drug Reward

    DTIC Science & Technology

    2010-06-01

    morphine . Conditioned drug reward is a relevant model in addiction because environmental cues (e.g. a barroom) induce craving and persistent... morphine . Synaptic plasticity is found in these neural fear and reward circuits and thus drugs which enhance plasticity like histone deacetylase...commercially available drug (sodium butyrate) with high translational utility for human studies. Morphine place conditioning: To measure effects of opiate

  19. Genomics of Drug Sensitivity in Cancer (GDSC): a resource for therapeutic biomarker discovery in cancer cells.

    PubMed

    Yang, Wanjuan; Soares, Jorge; Greninger, Patricia; Edelman, Elena J; Lightfoot, Howard; Forbes, Simon; Bindal, Nidhi; Beare, Dave; Smith, James A; Thompson, I Richard; Ramaswamy, Sridhar; Futreal, P Andrew; Haber, Daniel A; Stratton, Michael R; Benes, Cyril; McDermott, Ultan; Garnett, Mathew J

    2013-01-01

    Alterations in cancer genomes strongly influence clinical responses to treatment and in many instances are potent biomarkers for response to drugs. The Genomics of Drug Sensitivity in Cancer (GDSC) database (www.cancerRxgene.org) is the largest public resource for information on drug sensitivity in cancer cells and molecular markers of drug response. Data are freely available without restriction. GDSC currently contains drug sensitivity data for almost 75 000 experiments, describing response to 138 anticancer drugs across almost 700 cancer cell lines. To identify molecular markers of drug response, cell line drug sensitivity data are integrated with large genomic datasets obtained from the Catalogue of Somatic Mutations in Cancer database, including information on somatic mutations in cancer genes, gene amplification and deletion, tissue type and transcriptional data. Analysis of GDSC data is through a web portal focused on identifying molecular biomarkers of drug sensitivity based on queries of specific anticancer drugs or cancer genes. Graphical representations of the data are used throughout with links to related resources and all datasets are fully downloadable. GDSC provides a unique resource incorporating large drug sensitivity and genomic datasets to facilitate the discovery of new therapeutic biomarkers for cancer therapies.

  20. An implantable microdevice to perform high-throughput in vivo drug sensitivity testing in tumors

    PubMed Central

    Jonas, Oliver; Landry, Heather M.; Fuller, Jason E.; Santini, John T.; Baselga, Jose; Tepper, Robert I.; Cima, Michael J.; Langer, Robert

    2016-01-01

    Current anticancer chemotherapy relies on a limited set of in vitro or indirect prognostic markers of tumor response to available drugs. A more accurate analysis of drug sensitivity would involve studying tumor response in vivo. To this end, we have developed an implantable device that can perform drug sensitivity testing of several anticancer agents simultaneously inside the living tumor. The device contained reservoirs that released microdoses of single agents or drug combinations into spatially distinct regions of the tumor. The local drug concentrations were chosen to be representative of concentrations achieved during systemic treatment. Local efficacy and drug concentration profiles were evaluated for each drug or drug combination on the device, and the local efficacy was confirmed to be a predictor of systemic efficacy in vivo for multiple drugs and tumor models. Currently, up to 16 individual drugs or combinations can be assessed independently, without systemic drug exposure, through minimally invasive biopsy of a small region of a single tumor. This assay takes into consideration physiologic effects that contribute to drug response by allowing drugs to interact with the living tumor in its native microenvironment. Because these effects are crucial to predicting drug response, we envision that these devices will help identify optimal drug therapy before systemic treatment is initiated and could improve drug response prediction beyond the biomarkers and in vitro and ex vivo studies used today. These devices may also be used in clinical drug development to safely gather efficacy data on new compounds before pharmacological optimization. PMID:25904741

  1. Drug release from pH-sensitive polymeric micelles with different drug distributions: insight from coarse-grained simulations.

    PubMed

    Nie, Shu Yu; Lin, Wen Jing; Yao, Na; Guo, Xin Dong; Zhang, Li Juan

    2014-10-22

    How to control the release of drugs from pH-sensitive polymeric micelles is an issue of common concern, which is important to the effectiveness of the micelles. The components and properties of polymers can notably influence the drug distributions inside micelles which is a key factor that affects the drug release from the micelles. In this work, the dissipative particle dynamics simulation method is first used to study the structural transformation of micelles during the protonation process and the drug release process from micelles with different drug distributions. And then the effects of polymer structures, including different lengths of hydrophilic blocks, pH-sensitive blocks and hydrophobic blocks, on drug release are also studied. In the end, several corresponding design principles of pH-sensitive polymers for drug delivery are proposed according to the simulation results. This work is in favor of establishing qualitative rules for the design and optimization of congener polymers for desired drug delivery, which is of great significance to provide a potential approach for the development of new multiblock pH-sensitive polymeric micelles.

  2. Ingenious pH-sensitive dextran/mesoporous silica nanoparticles based drug delivery systems for controlled intracellular drug release.

    PubMed

    Zhang, Min; Liu, Jia; Kuang, Ying; Li, Qilin; Zheng, Di-Wei; Song, Qiongfang; Chen, Hui; Chen, Xueqin; Xu, Yanglin; Li, Cao; Jiang, Bingbing

    2017-02-04

    In this work, dextran, a polysaccharide with excellent biocompatibility, is applied as the "gatekeeper" to fabricate the pH-sensitive dextran/mesoporous silica nanoparticles (MSNs) based drug delivery systems for controlled intracellular drug release. Dextran encapsulating on the surface of MSNs is oxidized by NaIO4 to obtain three kinds of dextran dialdehydes (PADs), which are then coupled with MSNs via pH-sensitive hydrazone bond to fabricate three kinds of drug carriers. At pH 7.4, PADs block the pores to prevent premature release of anti-cancer drug doxorubicin hydrochloride (DOX). However, in the weakly acidic intracellular environment (pH∼5.5) the hydrazone can be ruptured; and the drug can be released from the carriers. The drug loading capacity, entrapment efficiency and release rates of the drug carriers can be adjusted by the amount of NaIO4 applied in the oxidation reaction. And from which DOX@MSN-NH-N=C-PAD10 is chosen as the most satisfactory one for the further in vitro cytotoxicity studies and cellular uptake studies. The results demonstrate that DOX@MSN-NH-N=C-PAD10 with an excellent pH-sensitivity can enter HeLa cells to release DOX intracellular due to the weakly acidic pH intracellular and kill the cells. In our opinion, the ingenious pH-sensitive drug delivery systems have application potentials for cancer therapy.

  3. Triclosan Derivatives: Towards Potent Inhibitors of Drug-Sensitive and Drug-Resistant Mycobacterium tuberculosis

    SciTech Connect

    Freundlich, Joel S.; Wang, Feng; Vilchèze, Catherine; Gulten, Gulcin; Langley, Robert; Schiehser, Guy A.; Jacobus, David P.; Jacobs, Jr., William R.; Sacchettini, James C.

    2009-06-30

    Isoniazid (INH) is a frontline antitubercular drug that inhibits the enoyl acyl carrier protein reductase InhA. Novel inhibitors of InhA that are not cross-resistant to INH represent a significant goal in antitubercular chemotherapy. The design, synthesis, and biological activity of a series of triclosan-based inhibitors is reported, including their promising efficacy against INH-resistant strains of M. tuberculosis. Triclosan has been previously shown to inhibit InhA, an essential enoyl acyl carrier protein reductase involved in mycolic acid biosynthesis, the inhibition of which leads to the lysis of Mycobacterium tuberculosis. Using a structure-based drug design approach, a series of 5-substituted triclosan derivatives was developed. Two groups of derivatives with alkyl and aryl substituents, respectively, were identified with dramatically enhanced potency against purified InhA. The most efficacious inhibitor displayed an IC{sub 50} value of 21 nM, which was 50-fold more potent than triclosan. X-ray crystal structures of InhA in complex with four triclosan derivatives revealed the structural basis for the inhibitory activity. Six selected triclosan derivatives were tested against isoniazid-sensitive and resistant strains of M. tuberculosis. Among those, the best inhibitor had an MIC value of 4.7 {mu}g mL{sup -1} (13 {mu}M), which represents a tenfold improvement over the bacteriocidal activity of triclosan. A subset of these triclosan analogues was more potent than isoniazid against two isoniazid-resistant M. tuberculosis strains, demonstrating the significant potential for structure-based design in the development of next generation antitubercular drugs.

  4. pH- and ion-sensitive polymers for drug delivery

    PubMed Central

    Yoshida, Takayuki; Lai, Tsz Chung; Kwon, Glen S; Sako, Kazuhiro

    2013-01-01

    Introduction Drug delivery systems (DDSs) are important for effective, safe, and convenient administration of drugs. pH- and ion-responsive polymers have been widely employed in DDS for site-specific drug release due to their abilities to exploit specific pH- or ion-gradients in the human body. Areas covered Having pH-sensitivity, cationic polymers can mask the taste of drugs and release drugs in the stomach by responding to gastric low pH. Anionic polymers responsive to intestinal high pH are used for preventing gastric degradation of drug, colon drug delivery and achieving high bioavailability of weak basic drugs. Tumor-targeted DDSs have been developed based on polymers with imidazole groups or poly(β-amino ester) responsive to tumoral low pH. Polymers with pH-sensitive chemical linkages, such as hydrazone, acetal, ortho ester and vinyl ester, pH-sensitive cell-penetrating peptides and cationic polymers undergoing pH-dependent protonation have been studied to utilize the pH gradient along the endocytic pathway for intracellular drug delivery. As ion-sensitive polymers, ion-exchange resins are frequently used for taste-masking, counterion-responsive drug release and sustained drug release. Polymers responding to ions in the saliva and gastrointestinal fluids are also used for controlled drug release in oral drug formulations. Expert opinion Stimuli-responsive DDSs are important for achieving site-specific and controlled drug release; however, intraindividual, interindividual and intercellular variations of pH should be considered when designing DDSs or drug products. Combination of polymers and other components, and deeper understanding of human physiology are important for development of pH- and ion-sensitive polymeric DDS products for patients. PMID:23930949

  5. Shear-stress sensitive lenticular vesicles for targeted drug delivery.

    PubMed

    Holme, Margaret N; Fedotenko, Illya A; Abegg, Daniel; Althaus, Jasmin; Babel, Lucille; Favarger, France; Reiter, Renate; Tanasescu, Radu; Zaffalon, Pierre-Léonard; Ziegler, André; Müller, Bert; Saxer, Till; Zumbuehl, Andreas

    2012-08-01

    Atherosclerosis results in the narrowing of arterial blood vessels and this causes significant changes in the endogenous shear stress between healthy and constricted arteries. Nanocontainers that can release drugs locally with such rheological changes can be very useful. Here, we show that vesicles made from an artificial 1,3-diaminophospholipid are stable under static conditions but release their contents at elevated shear stress. These vesicles have a lenticular morphology, which potentially leads to instabilities along their equator. Using a model cardiovascular system based on polymer tubes and an external pump to represent shear stress in healthy and constricted vessels of the heart, we show that drugs preferentially release from the vesicles in constricted vessels that have high shear stress.

  6. Drug Loading Capacity of Environmentally Sensitive Polymeric Microgels

    NASA Astrophysics Data System (ADS)

    McDonough, Ryan; Streletzky, Kiril; Bayachou, Mekki; Peiris, Pubudu

    2009-10-01

    Microgel nanoparticles consisting of cross-linked polymer hydroxypropyl cellulose chains have a temperature dependent volume phase transition, prompting the use of microgels for controlled drug transport. Drug particles aggregate in the slightly hydrophobic interior of microgels. Microgels are stored in equilibrium until the critical temperature (Tv) is reached and the volume phase transition limits available space, thus expelling the drugs. Our study was designed to test this property of microgels using amperometric electrochemical methods. A critical assumption was that small molecules inside microgels would not interact via diffusion with the electrode surface and thus total current would be decreased across the electrodes in a microgel sample. A room temperature (Troom) flow amperometric measurement comparing microgel/tylenol solution with control tylenol samples yielded about 20% tylenol concentration reduction of the microgel sample. Results from the steady state electrochemical experiment confirm the presence of about 20% tylenol concentration drop of the microgel sample compared to control sample at Troom. Using the steady-state experiment with a cyclic temperature ramp from Troom to beyond Tv showed that the tylenol concentration change between the temperature extremes was greater for the microgel solution than for the control solution.

  7. Nullifying drug-induced sensitization: behavioral and electrophysiological evaluations of dopaminergic and serotonergic ligands in methamphetamine-sensitized rats.

    PubMed

    McDaid, J; Tedford, C E; Mackie, A R; Dallimore, J E; Mickiewicz, A L; Shen, F; Angle, J M; Napier, T C

    2007-01-05

    Repeated exposure to methamphetamine produces a persistent enhancement of the acute motor effects of the drug, commonly referred to as behavioral sensitization. Behavioral sensitization involves monoaminergic projections to several forebrain nuclei. We recently revealed that the ventral pallidum (VP) may also be involved. In this study, we sought to establish if treatments with antagonists or partial agonists to monoaminergic receptors could "reverse" methamphetamine-induced behavioral and VP neuronal sensitization. Behavioral sensitization was obtained in rats with five once-daily s.c. injections of 2.5mg/kg methamphetamine, an effect that persisted for at least 60 days. After the development of sensitization, 15 once-daily treatments of mirtazapine (a 5-HT(2/3), alpha(2) and H(1) antagonist), SKF38393 (D(1) partial agonist) or SCH23390 (dopamine D(1) antagonist) nullified indices of motor sensitization as assessed by measuring the motoric response to an acute methamphetamine challenge 30 days after the fifth repeated methamphetamine treatment. VP neurons recorded in vivo from methamphetamine-sensitized rats at the 30-day withdrawal time also showed a robust downward shift in the excitatory responses observed to an acute i.v. methamphetamine challenge in non-sensitized rats. This decreased excitatory effect was reversed by mirtazapine, but not by other antagonists that were tested. These data suggest a potential therapeutic benefit for mirtazapine in the treatment of methamphetamine addiction, and point to a possible role for the VP in the sensitization process to methamphetamine.

  8. Ketal containing amphiphilic block copolymer micelles as pH-sensitive drug carriers.

    PubMed

    Lee, Iljae; Park, Minhyung; Kim, Yerang; Hwang, On; Khang, Gilson; Lee, Dongwon

    2013-05-01

    pH-Responsive linkages have been widely exploited in the development of polymeric drug delivery systems, which trigger drug release selectively at tumor tissues or endosomes and lysosomes of cells. Herein we report new pH-sensitive amphiphilic poly(ketal adipate)-co-poly(ethylene glycol) block copolymers (PKA-PEG), which have acid-cleavable ketal linkages in their hydrophobic backbone. PKA-PEG copolymers self-assemble to form stable micelles with a mean diameter of ~175 nm, which can encapsulate a payload of anticancer drugs and rapidly dissociate to release drug payload at the acid environment. The micelles are biocompatible and exhibit abilities to disrupt endosomes to enhance the cytosol drug delivery. Taken together, we anticipate that the pH-sensitive PKA-PEG micelles have great potential as anticancer drug carriers.

  9. In situ gelling stimuli-sensitive block copolymer hydrogels for drug delivery.

    PubMed

    He, Chaoliang; Kim, Sung Wan; Lee, Doo Sung

    2008-05-08

    Stimuli-sensitive block copolymer hydrogels, which are reversible polymer networks formed by physical interactions and exhibit a sol-gel phase-transition in response to external stimuli, have great potential in biomedical and pharmaceutical applications, especially in site-specific controlled drug-delivery systems. The drug may be mixed with a polymer solution in vitro and the drug-loaded hydrogel can form in situ after the in vivo administration, such as injection; therefore, stimuli-sensitive block copolymer hydrogels have many advantages, such as simple drug formulation and administration procedures, no organic solvent, site-specificity, a sustained drug release behavior, less systemic toxicity and ability to deliver both hydrophilic and hydrophobic drugs. Among the stimuli in the biomedical applications, temperature and pH are the most popular physical and chemical stimuli, respectively. The temperature- and/or pH-sensitive block copolymer hydrogels for biomedical applications have been extensively developed in the past decade. This review focuses on recent development of the preparation and application for drug delivery of the block copolymer hydrogels that respond to temperature, pH or both stimuli, including poly(N-substituted acrylamide)-based block copolymers, poloxamers and their derivatives, poly(ethylene glycol)-polyester block copolymers, polyelectrolyte-based block copolymers and the polyelectrolyte-modified thermo-sensitive block copolymers. In addition, the hydrogels based on other stimuli-sensitive block copolymers are discussed.

  10. Development of pH-sensitive self-nanoemulsifying drug delivery systems for acid-labile lipophilic drugs.

    PubMed

    Zhao, Tianjing; Maniglio, Devid; Chen, Jie; Chen, Bin; Migliaresi, Claudio

    2016-03-01

    Oral administration is the most convenient way of all the drug delivery routes. Orally administered bioactive compounds must resist the harsh acidic fluids or enzyme digestion in stomach, to reach their absorbed destination in small intestine. This is the case for silibinin, a drug used to protect liver cells against toxins that has also been demonstrated in vitro to possess anti-cancer effects. However, as many other drugs, silibinin can degrade in the stomach due to the action of the gastric fluid. The use of pH-sensitive self-nanoemulsifying drug delivery systems (pH-SNEDDS) could overcome the drawback due to degradation of the drug in the stomach while enhancing its solubility and dissolution rate. In this paper we have investigated pH-sensitive self-nanoemulsifying formulations containing silibinin as model drug. Pseudo-ternary phase diagrams have been constructed in order to identify the self-emulsification regions under different pH. Solubility of silibinin in selected formulations has been assessed and stability of the pure drug and of the silibinin loaded pH-SNEDDS formulations in simulated gastric fluid had been compared. Droplet size of the optimized pH-SNEDDS has been correlated to pH, volume of dilution medium and silibinin loading amount. TEM (transmission electron microscopy) studies have shown that emulsion droplets had spherical shape and narrow size distribution. In vitro drug release studies of the optimal pH-SNEDDS indicated substantial increase of the drug release and release rate in comparison to pure silibinin and to the commercial silibinin tablet. The results indicated that pH-SNEDDS have potential to improve the biopharmaceutics properties of acid-labile lipophilic drugs.

  11. Repurposing of antiparasitic drugs: the hydroxy-naphthoquinone buparvaquone inhibits vertical transmission in the pregnant neosporosis mouse model.

    PubMed

    Müller, Joachim; Aguado-Martínez, Adriana; Manser, Vera; Wong, Ho Ning; Haynes, Richard K; Hemphill, Andrew

    2016-02-17

    The three anti-malarial drugs artemiside, artemisone, and mefloquine, and the naphthoquinone buparvaquone known to be active against theileriosis in cattle and Leishmania infections in rodents, were assessed for activity against Neospora caninum infection. All four compounds inhibited the proliferation of N. caninum tachyzoites in vitro with IC50 in the sub-micromolar range, but artemisone and buparvaquone were most effective (IC50 = 3 and 4.9 nM, respectively). However, in a neosporosis mouse model for cerebral infection comprising Balb/c mice experimentally infected with the virulent isolate Nc-Spain7, the three anti-malarial compounds failed to exhibit any activity, since treatment did not reduce the parasite burden in brains and lungs compared to untreated controls. Thus, these compounds were not further evaluated in pregnant mice. On the other hand, buparvaquone, shown earlier to be effective in reducing the parasite load in the lungs in an acute neosporosis disease model, was further assessed in the pregnant mouse model. Buparvaquone efficiently inhibited vertical transmission in Balb/c mice experimentally infected at day 7 of pregnancy, reduced clinical signs in the pups, but had no effect on cerebral infection in the dams. This demonstrates proof-of-concept that drug repurposing may lead to the discovery of an effective compound against neosporosis that can protect offspring from vertical transmission and disease.

  12. Structure of Prolyl-tRNA Synthetase-Halofuginone Complex Provides Basis for Development of Drugs against Malaria and Toxoplasmosis.

    PubMed

    Jain, Vitul; Yogavel, Manickam; Oshima, Yoshiteru; Kikuchi, Haruhisa; Touquet, Bastien; Hakimi, Mohamed-Ali; Sharma, Amit

    2015-05-05

    The Chinese herb Dichroa febrifuga has traditionally treated malaria-associated fever. Its active component febrifugine (FF) and derivatives such as halofuginone (HF) are potent anti-malarials. Here, we show that FF-based derivatives arrest parasite growth by direct interaction with and inhibition of the protein translation enzyme prolyl-tRNA synthetase (PRS). Dual administration of inhibitors that target different tRNA synthetases suggests high utility of these drug targets. We reveal the ternary complex structure of PRS-HF and adenosine 5'-(β,γ-imido)triphosphate where the latter facilitates HF integration into the PRS active site. Structural analyses also highlight spaces within the PRS architecture for HF derivatization of its quinazolinone, but not piperidine, moiety. We also show a remarkable ability of HF to kill the related human parasite Toxoplasma gondii, suggesting wider HF efficacy against parasitic PRSs. Hence, our cell-, enzyme-, and structure-based data on FF-based inhibitors strengthen the case for their inclusion in anti-malarial and anti-toxoplasmosis drug development efforts.

  13. A Network Flow-Based Method to Predict Anticancer Drug Sensitivity

    PubMed Central

    Qin, Yufang; Chen, Ming; Wang, Haiyun; Zheng, Xiaoqi

    2015-01-01

    Predicting anticancer drug sensitivity can enhance the ability to individualize patient treatment, thus making development of cancer therapies more effective and safe. In this paper, we present a new network flow-based method, which utilizes the topological structure of pathways, for predicting anticancer drug sensitivities. Mutations and copy number alterations of cancer-related genes are assumed to change the pathway activity, and pathway activity difference before and after drug treatment is used as a measure of drug response. In our model, Contributions from different genetic alterations are considered as free parameters, which are optimized by the drug response data from the Cancer Genome Project (CGP). 10-fold cross validation on CGP data set showed that our model achieved comparable prediction results with existing elastic net model using much less input features. PMID:25992881

  14. Ototoxic drugs: difference in sensitivity between mice and guinea pigs.

    PubMed

    Poirrier, A L; Van den Ackerveken, P; Kim, T S; Vandenbosch, R; Nguyen, L; Lefebvre, P P; Malgrange, B

    2010-03-01

    The development of experimental animal models has played an invaluable role in understanding the mechanisms of neurosensory deafness and in devising effective treatments. The purpose of this study was to develop an adult mouse model of ototoxic drug-induced hearing loss and to compare the ototoxicity in the adult mouse to that in the well-described guinea pig model. Mice are a powerful model organism, especially due to the large availability of antibodies, probes and genetic mutants. In this study, mice (n=114) and guinea pigs (n=35) underwent systemic treatment with either kanamycin or cisplatin. Auditory brainstem responses showed a significant threshold shift in guinea pigs 2 weeks after the beginning of the ototoxic treatment, while there was no significant hearing impairment recorded in mice. Hair cells and neuronal loss were correlated with hearing function in both guinea pigs and mice. These results indicate that the mouse is not a good model for ototoxicity, which should be taken into consideration in all further investigations concerning ototoxicity-induced hearing loss.

  15. Drug predictive cues activate aversion-sensitive striatal neurons that encode drug seeking.

    PubMed

    Wheeler, Daniel S; Robble, Mykel A; Hebron, Emily M; Dupont, Matthew J; Ebben, Amanda L; Wheeler, Robert A

    2015-05-06

    Drug-associated cues have profound effects on an addict's emotional state and drug-seeking behavior. Although this influence must involve the motivational neural system that initiates and encodes the drug-seeking act, surprisingly little is known about the nature of such physiological events and their motivational consequences. Three experiments investigated the effect of a cocaine-predictive stimulus on dopamine signaling, neuronal activity, and reinstatement of cocaine seeking. In all experiments, rats were divided into two groups (paired and unpaired), and trained to self-administer cocaine in the presence of a tone that signaled the immediate availability of the drug. For rats in the paired group, self-administration sessions were preceded by a taste cue that signaled delayed drug availability. Assessments of hedonic responses indicated that this delay cue became aversive during training. Both the self-administration behavior and the immediate cue were subsequently extinguished in the absence of cocaine. After extinction of self-administration behavior, the presentation of the aversive delay cue reinstated drug seeking. In vivo electrophysiology and voltammetry recordings in the nucleus accumbens measured the neural responses to both the delay and immediate drug cues after extinction. Interestingly, the presentation of the delay cue simultaneously decreased dopamine signaling and increased excitatory encoding of the immediate cue. Most importantly, the delay cue selectively enhanced the baseline activity of neurons that would later encode drug seeking. Together these observations reveal how cocaine cues can modulate not only affective state, but also the neurochemical and downstream neurophysiological environment of striatal circuits in a manner that promotes drug seeking.

  16. Drug Predictive Cues Activate Aversion-Sensitive Striatal Neurons That Encode Drug Seeking

    PubMed Central

    Wheeler, Daniel S.; Robble, Mykel A.; Hebron, Emily M.; Dupont, Matthew J.; Ebben, Amanda L.

    2015-01-01

    Drug-associated cues have profound effects on an addict's emotional state and drug-seeking behavior. Although this influence must involve the motivational neural system that initiates and encodes the drug-seeking act, surprisingly little is known about the nature of such physiological events and their motivational consequences. Three experiments investigated the effect of a cocaine-predictive stimulus on dopamine signaling, neuronal activity, and reinstatement of cocaine seeking. In all experiments, rats were divided into two groups (paired and unpaired), and trained to self-administer cocaine in the presence of a tone that signaled the immediate availability of the drug. For rats in the paired group, self-administration sessions were preceded by a taste cue that signaled delayed drug availability. Assessments of hedonic responses indicated that this delay cue became aversive during training. Both the self-administration behavior and the immediate cue were subsequently extinguished in the absence of cocaine. After extinction of self-administration behavior, the presentation of the aversive delay cue reinstated drug seeking. In vivo electrophysiology and voltammetry recordings in the nucleus accumbens measured the neural responses to both the delay and immediate drug cues after extinction. Interestingly, the presentation of the delay cue simultaneously decreased dopamine signaling and increased excitatory encoding of the immediate cue. Most importantly, the delay cue selectively enhanced the baseline activity of neurons that would later encode drug seeking. Together these observations reveal how cocaine cues can modulate not only affective state, but also the neurochemical and downstream neurophysiological environment of striatal circuits in a manner that promotes drug seeking. PMID:25948270

  17. Targeting CDKs with Roscovitine Increases Sensitivity to DNA Damaging Drugs of Human Osteosarcoma Cells

    PubMed Central

    Hattinger, Claudia Maria; Fanelli, Marilù; Versteeg, Rogier; Koster, Jan; Picci, Piero

    2016-01-01

    Cyclin-dependent kinase 2 (CDK2) has been reported to be essential for cell proliferation in several human tumours and it has been suggested as an appropriate target to be considered in order to enhance the efficacy of treatment regimens based on the use of DNA damaging drugs. We evaluated the clinical impact of CDK2 overexpression on a series of 21 high-grade osteosarcoma (OS) samples profiled by using cDNA microarrays. We also assessed the in vitro efficacy of the CDKs inhibitor roscovitine in a panel of drug-sensitive and drug-resistant human OS cell lines. OS tumour samples showed an inherent overexpression of CDK2, and high expression levels at diagnosis of this kinase appeared to negatively impact on clinical outcome. CDK2 expression also proved to be relevant for in vitro OS cells growth. These findings indicated CDK2 as a promising candidate therapeutic marker for OS and therefore we assessed the efficacy of the CDKs-inhibitor roscovitine in both drug-sensitive and -resistant OS cell lines. All cell lines resulted to be responsive to roscovitine, which was also able to increase the activity of cisplatin and doxorubicin, the two most active DNA damaging drugs used in OS chemotherapy. Our results indicated that combined treatment with conventional OS chemotherapeutic drugs and roscovitine may represent a new candidate intervention approach, which may be considered to enhance tumour cell sensitivity to DNA damaging drugs. PMID:27898692

  18. Integrating Domain Specific Knowledge and Network Analysis to Predict Drug Sensitivity of Cancer Cell Lines

    PubMed Central

    Kim, Sebo; Sundaresan, Varsha; Zhou, Lei; Kahveci, Tamer

    2016-01-01

    One of fundamental challenges in cancer studies is that varying molecular characteristics of different tumor types may lead to resistance to certain drugs. As a result, the same drug can lead to significantly different results in different types of cancer thus emphasizing the need for individualized medicine. Individual prediction of drug response has great potential to aid in improving the clinical outcome and reduce the financial costs associated with prescribing chemotherapy drugs to which the patient’s tumor might be resistant. In this paper we develop a network based classifier (NBC) method for predicting sensitivity of cell lines to anticancer drugs from transcriptome data. In the literature, this strategy has been used for predicting cancer types. Here, we extend it to estimate sensitivity of cells from different tumor types to various anticancer drugs. Furthermore, we incorporate domain specific knowledge such as the use of apoptotic gene list and clinical dose information in our method to impart biological significance to the prediction. Our experimental results suggest that our network based classifier (NBC) method outperforms existing classifiers in estimating sensitivity of cell lines for different drugs. PMID:27607242

  19. Drug sensitivity patterns of HHV8 carrying body cavity lymphoma cell lines

    PubMed Central

    2011-01-01

    Background Primary effusion lymphoma (PEL) is a rare KSHV/HHV8-associated high-grade non-Hodgkin's lymphoma (NHL) of B-cell origin, characterized by serous effusions in body cavities. Most patients are HIV-infected men with severe immunosuppression and other HHV8-associated diseases such as Kaposi's sarcoma (KS). The prognosis for those infected is poor, with a median survival of less than 6 months in most cohorts. Sustained complete remission is rare. High-dose chemotherapy regimens are used to improve remission rate and survival. The aim of the present study was to compare the drug sensitivity pattern of the available primary effusion (body cavity based) lymphoma-derived cell lines in order to find additional, potentially effective drugs that are not included in current chemotherapy treatment protocols. Methods We have analyzed 11 cell lines against 27 frequently used cytostatic drugs in short term (3 days) survival assays using automated high throughput confocal microscopy. Results All cell lines showed a distinct, individual drug sensitivity pattern. Considering the in vitro used and clinically achieved drug concentration, Vinorelbine, Paclitaxel, Epirubicin and Daunorubicin were the most effective drugs. Conclusions We suggest that inclusion of the above drugs into PEL chemotherapy protocols may be justified. The heterogeneity in the drug response pattern however indicated that assay-guided individualized therapy might be required to optimize therapeutic response. PMID:21992895

  20. pH-Sensitive drug delivery system based on modified dextrin coated mesoporous silica nanoparticles.

    PubMed

    Chen, Hongyu; Zheng, Diwei; Liu, Jia; Kuang, Ying; Li, Qilin; Zhang, Min; Ye, Haifeng; Qin, Hongyang; Xu, Yanglin; Li, Cao; Jiang, Bingbing

    2016-04-01

    In this work, a novel pH-sensitive drug delivery system based on modified dextrin coated mesoporous silica nanoparticles (MSNs), DOX@MSN-DDA-CL, are prepared. The dextrin grafting on the surface of MSNs is oxidized by KIO4 to obtain dextrin dialdehyde, which is then cross-linked by tetraethylenepentamine through a pH-sensitive Schiff's base. Under physiological conditions, the cross-linked dextrin dialdehyde blocks the pores to prevent premature release of model drug doxorubicin hydrochloride (DOX). In the weak acidic environment, pH 6.0 in this work, the Schiff's base can be hydrolyzed and released the drug. The in vitro drug release studies at different pHs prove the pH-sensitivity of DOX@MSN-DDA-CL. The cytotoxicity and cell internalization behavior are also investigated in detail. In vivo tissue distribution and pharmacokinetics with a H22-bearing mouse animal mode are also studied, prove that DOX@MSN-DDA-CL has a longer retention time than that of pure DOX and can accumulate in tumor region via enhanced permeation and retention and nanomaterials-induced endothelial cell leakiness effects. In conclusion, the pH-sensitive modified dextrin/MSNs complex drug delivery system has a great potential for cancer therapy.

  1. Drug procurement, the Global Fund and misguided competition policies.

    PubMed

    Tren, Richard; Hess, Kimberly; Bate, Roger

    2009-12-22

    In an effort to increase competition and decrease price, the Global Fund to Fight AIDS, Tuberculosis and Malaria recently began asking some grant recipients to use international competitive bidding processes for certain drug purchases. Unfortunately, for countries like Kenya, this request has caused more harm than good. After awarding the tender for its annual supply of the anti-malarial artemether-lumefantrine to the lowest bidder, Ajanta Pharma, Kenya experienced wide stock-outs in part due to the company's inability to supply the order in full and on time. Similar problems could arise in Uganda. Despite Kenya's experience, Uganda has awarded its next tender for artemether-lumefantrine to Ajanta Pharma. Uganda is already facing wide stock-outs and risks exacerbating an already dire situation the longer it takes to fulfil the procurement contract. A tender process based primarily on price cannot account for a company's ability to consistently supply sufficient product in time.

  2. Malaria in South America: a drug discovery perspective

    PubMed Central

    2013-01-01

    The challenge of controlling and eventually eradicating malaria means that new tools are urgently needed. South America’s role in this fight spans both ends of the research and development spectrum: both as a continent capable of discovering and developing new medicines, and also as a continent with significant numbers of malaria patients. This article reviews the contribution of groups in the South American continent to the research and development of new medicines over the last decade. Therefore, the current situation of research targeting malaria control and eradication is discussed, including endemicity, geographical distribution, treatment, drug-resistance and diagnosis. This sets the scene for a review of efforts within South America to discover and optimize compounds with anti-malarial activity. PMID:23706107

  3. Prenatal tactile stimulation attenuates drug-induced behavioral sensitization, modifies behavior, and alters brain architecture.

    PubMed

    Muhammad, Arif; Kolb, Bryan

    2011-07-11

    Based on the findings of postnatal tactile stimulation (TS), a favorable experience in rats, the present study examined the influence of prenatal TS on juvenile behavior, adult amphetamine (AMPH) sensitization, and structural alteration in the prefrontal cortex (PFC) and the striatum. Female rats received TS through a baby hair brush throughout pregnancy, and the pups born were tested for open field locomotion, elevated plus maze (EPM), novel object recognition (NOR), and play fighting behaviors. Development and persistence of drug-induced behavioral sensitization in adults were tested by repeated AMPH administration and a challenge, respectively. Structural plasticity in the brain was assessed from the prefrontal cortical thickness and striatum size from serial coronal sections. The results indicate that TS females showed enhanced exploration in the open field. TS decreased the frequency of playful attacks whereas the response to face or evade an attack was not affected. Anxiety-like behavior and cognitive performance were not influenced by TS. AMPH administration resulted in gradual increase in locomotor activity (i.e., behavioral sensitization) that persisted at least for 2 weeks. However, both male and female TS rats exhibited attenuated AMPH sensitization compared to sex-matched controls. Furthermore, the drug-associated alteration in the prefrontal cortical thickness and striatum size observed in controls were prevented by TS experience. In summary, TS during prenatal development modified juvenile behavior, attenuated drug-induced behavioral sensitization in adulthood, and reorganized brain regions implicated in drug addiction.

  4. Synthesis of a dextran based thermo-sensitive drug delivery system by gamma irradiation.

    PubMed

    Almeida, J F; Ferreira, P; Alves, P; Lopes, A; Gil, M H

    2013-10-01

    Gamma radiation was used as the initiator/crosslinker agent for the synthesis of thermo-sensitive hydrogel networks, under the form of membranes, using dextran and N-isopropylacrylamide. The prepared membranes were loaded with Ondansetron™, a potent antiemetic drug and tested as drug delivery systems. The characterization of the materials was accomplished by: Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy, elemental analysis, lower critical solution temperature (LCST) determination, swelling behaviour evaluation, determination of surface energy by contact angle measurement and drug delivery kinetics studies. Also, the influence of irradiation time and temperature on the materials properties was evaluated.

  5. Heat Shock Protein translocation induced by membrane fluidization increases tumor-cell sensitivity to chemotherapeutic drugs.

    PubMed

    Dempsey, Nina C; Ireland, H Elyse; Smith, Carly M; Hoyle, Christine F; Williams, John H H

    2010-10-28

    Treatment of chronic lymphocytic leukemia (CLL) remains a challenge due to the frequency of drug resistance amongst patients. Improving the delivery of chemotherapeutic agents while reducing the expression of anti-apoptotic Heat Shock Proteins (HSPs) within the cancer cells may facilitate in overcoming this drug resistance. We demonstrate for the first time that sub-lethal doses of chemotherapeutic agents can be combined with membrane fluidizing treatments to produce a significant increase in drug efficacy and apoptosis in vitro. We show that fluidizers result in a transient decrease in intracellular HSPs, resulting in increased tumor-cell sensitivity and a membrane-associated induction of HSP gene expression.

  6. Drugs of abuse specifically sensitize noradrenergic and serotonergic neurons via a non-dopaminergic mechanism.

    PubMed

    Lanteri, Christophe; Salomon, Lucas; Torrens, Yvette; Glowinski, Jacques; Tassin, Jean-Pol

    2008-06-01

    A challenge in drug dependence is to delineate long-term neurochemical modifications induced by drugs of abuse. Repeated d-amphetamine was recently shown to disrupt a mutual regulatory link between noradrenergic and serotonergic neurons, thus inducing long-term increased responses to d-amphetamine and para-chloroamphetamine, respectively. We show here that such a sensitization of noradrenergic and serotonergic neurons also occurs following repeated treatment with cocaine, morphine, or alcohol, three compounds belonging to main groups of addictive substances. In all cases, this sensitization is prevented by alpha 1b-adrenergic and 5-HT2A receptors blockade, indicating the critical role of these receptors on long-term effects of drugs of abuse. However, repeated treatments with two non-addictive antidepressants, venlafaxine, and clorimipramine, which nevertheless inhibit noradrenergic and serotonergic reuptake, do not induce noradrenergic and serotonergic neurons sensitization. Similarly, this sensitization does not occur following repeated treatments with a specific inhibitor of dopamine (DA) reuptake, GBR12783. Moreover, we show that the effects of SCH23390, a D1 receptor antagonist known to inhibit development of d-amphetamine behavioral sensitization, are due to its 5-HT2C receptor agonist property. SCH23390 blocks amphetamine-induced release of norepinephrine and RS102221, a 5-HT2C antagonist, can reverse this inhibition as well as inhibition of noradrenergic sensitization and development of behavioral sensitization induced by repeated d-amphetamine. We propose that noradrenergic/serotonergic uncoupling is a common neurochemical consequence of repeated consumption of drugs of abuse, unrelated with DA release. Our data also suggest that compounds able to restore the link between noradrenergic and serotonergic modulatory systems could represent important therapeutic targets for investigation.

  7. Increased sensitivity to platinum drugs of cancer cells with acquired resistance to trabectedin

    PubMed Central

    Colmegna, B; Uboldi, S; Frapolli, R; Licandro, S A; Panini, N; Galmarini, C M; Badri, Nadia; Spanswick, V J; Bingham, J P; Kiakos, Konstantinos; Erba, E; Hartley, J A; D'Incalci, M

    2015-01-01

    Background: In order to investigate the mechanisms of acquired resistance to trabectedin, trabectedin-resistant human myxoid liposarcoma (402-91/T) and ovarian carcinoma (A2780/T) cell lines were derived and characterised in vitro and in vivo. Methods: Resistant cell lines were obtained by repeated exposures to trabectedin. Characterisation was performed by evaluating drug sensitivity, cell cycle perturbations, DNA damage and DNA repair protein expression. In vivo experiments were performed on A2780 and A2780/T xenografts. Results: 402-91/T and A2780/T cells were six-fold resistant to trabectedin compared with parental cells. Resistant cells were found to be hypersensitive to UV light and did not express specific proteins involved in the nucleotide excision repair (NER) pathway: XPF and ERCC1 in 402-91/T and XPG in A2780/T. NER deficiency in trabectedin-resistant cells was associated with the absence of a G2/M arrest induced by trabectedin and with enhanced sensitivity (two-fold) to platinum drugs. In A2780/T, this collateral sensitivity, confirmed in vivo, was associated with an increased formation of DNA interstrand crosslinks. Conclusions: Our finding that resistance to trabectedin is associated with the loss of NER function, with a consequent increased sensitivity to platinum drugs, provides the rational for sequential use of these drugs in patients who have acquired resistance to trabectedin. PMID:26633559

  8. A Copula Based Approach for Design of Multivariate Random Forests for Drug Sensitivity Prediction

    PubMed Central

    Haider, Saad; Rahman, Raziur; Ghosh, Souparno; Pal, Ranadip

    2015-01-01

    Modeling sensitivity to drugs based on genetic characterizations is a significant challenge in the area of systems medicine. Ensemble based approaches such as Random Forests have been shown to perform well in both individual sensitivity prediction studies and team science based prediction challenges. However, Random Forests generate a deterministic predictive model for each drug based on the genetic characterization of the cell lines and ignores the relationship between different drug sensitivities during model generation. This application motivates the need for generation of multivariate ensemble learning techniques that can increase prediction accuracy and improve variable importance ranking by incorporating the relationships between different output responses. In this article, we propose a novel cost criterion that captures the dissimilarity in the output response structure between the training data and node samples as the difference in the two empirical copulas. We illustrate that copulas are suitable for capturing the multivariate structure of output responses independent of the marginal distributions and the copula based multivariate random forest framework can provide higher accuracy prediction and improved variable selection. The proposed framework has been validated on genomics of drug sensitivity for cancer and cancer cell line encyclopedia database. PMID:26658256

  9. Anticancer drug clustering in lung cancer based on gene expression profiles and sensitivity database

    PubMed Central

    Gemma, Akihiko; Li, Cai; Sugiyama, Yuka; Matsuda, Kuniko; Seike, Yoko; Kosaihira, Seiji; Minegishi, Yuji; Noro, Rintaro; Nara, Michiya; Seike, Masahiro; Yoshimura, Akinobu; Shionoya, Aki; Kawakami, Akiko; Ogawa, Naoki; Uesaka, Haruka; Kudoh, Shoji

    2006-01-01

    background The effect of current therapies in improving the survival of lung cancer patients remains far from satisfactory. It is consequently desirable to find more appropriate therapeutic opportunities based on informed insights. A molecular pharmacological analysis was undertaken to design an improved chemotherapeutic strategy for advanced lung cancer. Methods We related the cytotoxic activity of each of commonly used anti-cancer agents (docetaxel, paclitaxel, gemcitabine, vinorelbine, 5-FU, SN38, cisplatin (CDDP), and carboplatin (CBDCA)) to corresponding expression pattern in each of the cell lines using a modified NCI program. Results We performed gene expression analysis in lung cancer cell lines using cDNA filter and high-density oligonucleotide arrays. We also examined the sensitivity of these cell lines to these drugs via MTT assay. To obtain our reproducible gene-drug sensitivity correlation data, we separately analyzed two sets of lung cancer cell lines, namely 10 and 19. In our gene-drug correlation analyses, gemcitabine consistently belonged to an isolated cluster in a reproducible fashion. On the other hand, docetaxel, paclitaxel, 5-FU, SN-38, CBDCA and CDDP were gathered together into one large cluster. Conclusion These results suggest that chemotherapy regimens including gemcitabine should be evaluated in second-line chemotherapy in cases where the first-line chemotherapy did not include this drug. Gene expression-drug sensitivity correlations, as provided by the NCI program, may yield improved therapeutic options for treatment of specific tumor types. PMID:16813650

  10. Lactate as a Novel Quantitative Measure of Viability in Schistosoma mansoni Drug Sensitivity Assays

    PubMed Central

    Howe, Stephanie; Zöphel, Dorina; Subbaraman, Harini; Unger, Clemens; Held, Jana; Engleitner, Thomas; Hoffmann, Wolfgang H.

    2014-01-01

    Whole-organism compound sensitivity assays are a valuable strategy in infectious diseases to identify active molecules. In schistosomiasis drug discovery, larval-stage Schistosoma allows the use of a certain degree of automation in the screening of compounds. Unfortunately, the throughput is limited, as drug activity is determined by manual assessment of Schistosoma viability by microscopy. To develop a simple and quantifiable surrogate marker for viability, we targeted glucose metabolism, which is central to Schistosoma survival. Lactate is the end product of glycolysis in human Schistosoma stages and can be detected in the supernatant. We assessed lactate as a surrogate marker for viability in Schistosoma drug screening assays. We thoroughly investigated parameters of lactate measurement and performed drug sensitivity assays by applying schistosomula and adult worms to establish a proof of concept. Lactate levels clearly reflected the viability of schistosomula and correlated with schistosomulum numbers. Compounds with reported potencies were tested, and activities were determined by lactate assay and by microscopy. We conclude that lactate is a sensitive and simple surrogate marker to be measured to determine Schistosoma viability in compound screening assays. Low numbers of schistosomula and the commercial availability of lactate assay reagents make the assay particularly attractive to throughput approaches. Furthermore, standardization of procedures and quantitative evaluation of compound activities facilitate interassay comparisons of potencies and, thus, concerted drug discovery approaches. PMID:25487803

  11. A community effort to assess and improve drug sensitivity prediction algorithms.

    PubMed

    Costello, James C; Heiser, Laura M; Georgii, Elisabeth; Gönen, Mehmet; Menden, Michael P; Wang, Nicholas J; Bansal, Mukesh; Ammad-ud-din, Muhammad; Hintsanen, Petteri; Khan, Suleiman A; Mpindi, John-Patrick; Kallioniemi, Olli; Honkela, Antti; Aittokallio, Tero; Wennerberg, Krister; Collins, James J; Gallahan, Dan; Singer, Dinah; Saez-Rodriguez, Julio; Kaski, Samuel; Gray, Joe W; Stolovitzky, Gustavo

    2014-12-01

    Predicting the best treatment strategy from genomic information is a core goal of precision medicine. Here we focus on predicting drug response based on a cohort of genomic, epigenomic and proteomic profiling data sets measured in human breast cancer cell lines. Through a collaborative effort between the National Cancer Institute (NCI) and the Dialogue on Reverse Engineering Assessment and Methods (DREAM) project, we analyzed a total of 44 drug sensitivity prediction algorithms. The top-performing approaches modeled nonlinear relationships and incorporated biological pathway information. We found that gene expression microarrays consistently provided the best predictive power of the individual profiling data sets; however, performance was increased by including multiple, independent data sets. We discuss the innovations underlying the top-performing methodology, Bayesian multitask MKL, and we provide detailed descriptions of all methods. This study establishes benchmarks for drug sensitivity prediction and identifies approaches that can be leveraged for the development of new methods.

  12. Increased Replicative Fitness Can Lead to Decreased Drug Sensitivity of Hepatitis C Virus

    PubMed Central

    Sheldon, Julie; Beach, Nathan M.; Moreno, Elena; Gallego, Isabel; Piñeiro, David; Martínez-Salas, Encarnación; Gregori, Josep; Quer, Josep; Esteban, Juan Ignacio; Rice, Charles M.

    2014-01-01

    ABSTRACT Passage of hepatitis C virus (HCV) in human hepatoma cells resulted in populations that displayed partial resistance to alpha interferon (IFN-α), telaprevir, daclatasvir, cyclosporine, and ribavirin, despite no prior exposure to these drugs. Mutant spectrum analyses and kinetics of virus production in the absence and presence of drugs indicate that resistance is not due to the presence of drug resistance mutations in the mutant spectrum of the initial or passaged populations but to increased replicative fitness acquired during passage. Fitness increases did not alter host factors that lead to shutoff of general host cell protein synthesis and preferential translation of HCV RNA. The results imply that viral replicative fitness is a mechanism of multidrug resistance in HCV. IMPORTANCE Viral drug resistance is usually attributed to the presence of amino acid substitutions in the protein targeted by the drug. In the present study with HCV, we show that high viral replicative fitness can confer a general drug resistance phenotype to the virus. The results exclude the possibility that genomes with drug resistance mutations are responsible for the observed phenotype. The fact that replicative fitness can be a determinant of multidrug resistance may explain why the virus is less sensitive to drug treatments in prolonged chronic HCV infections that favor increases in replicative fitness. PMID:25122776

  13. Polypyrrole nanoparticles for tunable, pH-sensitive and sustained drug release

    NASA Astrophysics Data System (ADS)

    Samanta, Devleena; Meiser, Jana L.; Zare, Richard N.

    2015-05-01

    We report the development of a generalized pH-sensitive drug delivery system that can release any charged drug preferentially at the pH range of interest. Our system is based on polypyrrole nanoparticles (PPy NPs), synthesized via a simple one-step microemulsion technique. These nanoparticles are highly monodisperse, stable in solution over the period of a month, and have good drug loading capacity (~15 wt%). We show that PPy NPs can be tuned to release drugs at both acidic and basic pH by varying the pH, the charge of the drug, as well as by adding small amounts of charged amphiphiles. Moreover, these NPs may be delivered locally by immobilizing them in a hydrogel. Our studies show encapsulation within a calcium alginate hydrogel results in sustained release of the incorporated drug for more than 21 days. Such a nanoparticle-hydrogel composite drug delivery system is promising for treatment of long-lasting conditions such as cancer and chronic pain which require controlled, localized, and sustained drug release.

  14. Behavioral sensitization of the reinforcing value of food: What food and drugs have in common.

    PubMed

    Temple, Jennifer L

    2016-11-01

    Sensitization is a basic property of the nervous system whereby repeated exposure to a stimulus results in an increase in responding to that stimulus. This increase in responding contributes to difficulty with treatment of drug abuse, as stimuli associated with substance use become signals or triggers for drug craving and relapse. Our work over the past decade has applied the theoretical framework of incentive sensitization to overeating. We have shown, in several studies, that lean adults do not commonly demonstrate behavioral sensitization after repeated exposure to snack food, but a subset of obese adults reliably does. This review will discuss this change in behavioral response to repeated consumption of snack food in obese individuals and apply the theoretical framework of incentive sensitization to drugs of abuse to high fat/high sugar snack foods. We will also show data that suggest that behavioral sensitization to repeated administration of snack food is predictive of weight gain, which may enhance its utility as a diagnostic tool for identifying at-risk individuals for obesity. Finally, we will discuss the future directions of this line of research, including studying the phenomenon in children and adolescents and determining if similar principles can be used to increase motivation to eat healthier food. A combination of reductions in unhealthy food intake and increases and healthy food intake is necessary to reduce obesity rates and improve health.

  15. Synthesis and evaluation of sensitizer drug photorelease chemistry: Micro-optic method applied to singlet oxygen generation and drug delivery

    NASA Astrophysics Data System (ADS)

    Ghosh, Goutam

    This thesis summarizes a new micro-optic method for singlet oxygen generation and sensitizer drug delivery, which include i) synthesis and evaluation of a first generation device for drug delivery from native and fluorinated silica probe tips, ii) synthesis of PEG conjugated sensitizers to study phototoxicity in ovarian cancer cells, and iii) synthesis and evaluation of tris-PEGylated chlorin conjugated fluorinated silica for its future integration into the device to use as a 2nd generation device. A first generation micro-optic device was developed that works by sparging O2 gas and light generating cytotoxic singlet oxygen that cleaves the covalently attached drug (sensitizer) from the probe tip at the distal end of the fiber. The aim is to develop a 1st and 2nd generation device for site specific delivery of photosensitizer and singlet oxygen to overcome the challenges involved in systemic administration of the sensitizer. Synthesis and evaluation of drug (pheophorbide-a) delivery applying micro-optic method from native and fluorinated silica probe tip was achieved. The amount of sensitizer photocleavage depends on the loading level of sensitizer onto the probe tips. We also found that photorelease efficiency depends on the nature of the solvents where sensitizer is photocleaved. For example, no photorelease was observed in an aqueous solvent where sensitizer remained adsorbed to the native silica probe-tip. But, 90% photocleavage was obtained in octanol. A significant amount of photosensitizer (formate ester of pyropheophorbide- a) diffused into the liposome when photocleavage study was carried out in liposome. Substantial increase of photorelease was observed in organic solvent when pyropheophorbide-a (PPa) sensitizer was attached to the partially fluorinated porous Vycor glass. We also explored sensitizer photorelease from the fluorinated silica surface at various temperatures and we found that autocatalytic photorelease happened at room temperature and above

  16. One-step synthesis of interpenetrating network hydrogels: Environment sensitivities and drug delivery properties

    PubMed Central

    Lu, Jingqiong; Li, Yinhui; Hu, Deng; Chen, Xiaoling; Liu, Yongmei; Wang, Liping; Ashraf, Muhammmad Aqeel; Zhao, Yansheng

    2015-01-01

    A novel interpenetrating network hydrogel for drug controlled release, composed of modified poly(aspartic acid) (KPAsp) and carboxymethyl chitosan (CMCTS), was prepared in aqueous system. The surface morphology and composition of hydrogels were characterized by SEM and FTIR. The swelling properties of KPAsp, KPAsp/CMCTS semi-IPN and KPAsp/CMCTS IPN hydrogels were investigated and the swelling dynamics of the hydrogels was analyzed based on the Fickian equation. The pH, temperature and salt sensitivities of hydrogels were further studied, and the prepared hydrogels showed extremely sensitive properties to pH, temperature, the ionic salts kinds and concentration. The results of controlled drug release behaviors of the hydrogels revealed that the introduction of IPN observably improved the drug release properties of hydrogels, the release rate of drug from hydrogels can be controlled by the structure of the hydrogels and pH value of the external environment, a relative large amount of drug released was preferred under simulated intestinal fluid. These results illustrated high potential of the KPAsp/CMCTS IPN hydrogels for application as drug carriers. PMID:26858562

  17. pH sensitive coiled coils: a strategy for enhanced liposomal drug delivery

    NASA Astrophysics Data System (ADS)

    Reja, Rahi M.; Khan, Mohsina; Singh, Sumeet K.; Misra, Rajkumar; Shiras, Anjali; Gopi, Hosahudya N.

    2016-02-01

    Stimuli responsive controlled release from liposome based vesicles is a promising strategy for the site specific delivery of drugs. Herein, we report the design of pH sensitive coiled coils and their incorporation into the liposome as triggers for the controlled release of encapsulated drugs. The designed coiled coil peptides with the incorporation of environment sensitive fluorescent amino acids were found to be stable at physiological pH and unstructured while changing the pH of the environment to either acidic or basic. This pH dependent conformational switch of the coiled-coil polypeptides was exploited as triggers for the enhanced release of the encapsulated drug molecules from liposomes. The SEM, DLS and TEM analysis revealed the uniform morphology of the peptide liposome hybrid vesicles. Further, the drug encapsulated liposome internalization experiments with cancer cells revealed the enhanced release and accumulation of drugs in the acidic lysosomal compartments in comparison with liposomes without coiled coils.Stimuli responsive controlled release from liposome based vesicles is a promising strategy for the site specific delivery of drugs. Herein, we report the design of pH sensitive coiled coils and their incorporation into the liposome as triggers for the controlled release of encapsulated drugs. The designed coiled coil peptides with the incorporation of environment sensitive fluorescent amino acids were found to be stable at physiological pH and unstructured while changing the pH of the environment to either acidic or basic. This pH dependent conformational switch of the coiled-coil polypeptides was exploited as triggers for the enhanced release of the encapsulated drug molecules from liposomes. The SEM, DLS and TEM analysis revealed the uniform morphology of the peptide liposome hybrid vesicles. Further, the drug encapsulated liposome internalization experiments with cancer cells revealed the enhanced release and accumulation of drugs in the acidic

  18. Salinomycin sensitizes antimitotic drugs-treated cancer cells by increasing apoptosis via the prevention of G2 arrest

    SciTech Connect

    Kim, Ju-Hwa; Yoo, Hye-In; Kang, Han Sung; Ro, Jungsil; Yoon, Sungpil

    2012-02-03

    Highlights: Black-Right-Pointing-Pointer Sal sensitizes antimitotic drugs-treated cancer cells. Black-Right-Pointing-Pointer Sal sensitizes them by prevention of G2 arrest and reduced cyclin D1 levels. Black-Right-Pointing-Pointer Sal also sensitizes them by increasing DNA damage and reducing p21 level. Black-Right-Pointing-Pointer A low concentration of Sal effectively sensitized the cancer cells to antimitotic drugs. -- Abstract: Here, we investigated whether Sal could sensitize cancer cells to antimitotic drugs. We demonstrated that Sal sensitized paclitaxcel (PAC)-, docetaxcel (DOC)-, vinblastin (VIN)-, or colchicine (COL)-treated cancer cell lines, suggesting that Sal has the ability to sensitize the cells to any form of microtubule-targeting drugs. Sensitization to the antimitotic drugs could be achieved with very low concentrations of Sal, suggesting that there is a possibility to minimize Sal toxicity associated with human cancer patient treatments. Sensitization by Sal increased apoptosis, which was observed by C-PARP production. Sal sensitized the cancer cells to antimitotic drugs by preventing G2 arrest, suggesting that Sal contributes to the induction of mitotic catastrophe. Sal generally reduced cyclin D1 levels in PAC-, DOC-, and VIN-treated cells. In addition, Sal treatment increased pH2AX levels and reduced p21 levels in antimitotic drugs-treated cells. These observations suggest that the mechanisms underlying Sal sensitization to DNA-damaging compounds, radiation, and microtubule-targeting drugs are similar. Our data demonstrated that Sal sensitizes cancer cells to antimitotic drugs by increasing apoptosis through the prevention of G2 arrest via conserved Sal-sensitization mechanisms. These results may contribute to the development of Sal-based chemotherapy for cancer patients treated with antimitotic drugs.

  19. pH-sensitive, polymer modified, plasma stable niosomes: promising carriers for anti-cancer drugs

    PubMed Central

    Tila, Dena; Yazdani-Arazi, Seyede Narjes; Ghanbarzadeh, Saeed; Arami, Sanam; Pourmoazzen, Zhaleh

    2015-01-01

    The aim of this study was the design and evaluation of a novel plasma stable, pH-sensitive niosomal formulation of Mitoxantrone by a modified ethanol injection method. Cholesterol hemisuccinate was added instead of cholesterol in order to produce pH-sensitivity property and using PEG-Poly (monomethyl itaconate)-CholC6 (PEG-PMMI-CholC6) copolymer introduced simultaneously pH-sensitivity and plasma stability properties in prepared niosomes. The pH-sensitivity and cytotoxicity of Mitoxantrone niosomes were evaluated in vitro in phosphate buffer with different pHs as well as using human ovarian cancer cell line (OVCAR-3), human breast cancer cell line (MCF-7) and human umbilical vein endothelial cells (HUVEC). Results showed that both cholesterol derivatives bearing formulations had pH-sensitive property and were found to release their contents under mild acidic conditions rapidly. In addition, the PEG-PMMI-CholC6-based niosomes could reserve the pH-sensitivity after incubation in plasma. Both Mitoxantrone-loaded pH-sensitive niosomes showed higher cytotoxicity than the conventional niosomes on OVCAR-3 and MCF-7 cell lines. However, both pH-sensitive niosomes exhibited lower cytotoxic effect on HUVEC cell line. Plasma stable, pH-sensitive niosomes could improve the cytotoxic effect and reduce the side effects of anti-tumor drugs. PMID:26417350

  20. Role of pressure-sensitive adhesives in transdermal drug delivery systems.

    PubMed

    Lobo, Shabbir; Sachdeva, Sameer; Goswami, Tarun

    2016-01-01

    Transdermal drug delivery systems (TDDS) are employed for the delivery of drugs across skin into the systemic circulation. Pressure-sensitive adhesive (PSA) is one of the most critical components used in a TDDS. The primary function of PSA is to help in adhesion of patch to skin, but more importantly it acts as a matrix for the drug and other excipients. Hence, apart from adhesion of the patch, PSA also affects other critical quality attributes of the TDDS such as drug delivery, flux through skin and physical and chemical stability of the finished product. This review article provides a summary of the adhesives used in various types of TDDS. In particular, this review will cover the design types of TDDS, categories of PSAs and their evaluation and regulatory aspects.

  1. Metabolic glycoengineering sensitizes drug-resistant pancreatic cancer cells to tyrosine kinase inhibitors erlotinib and gefitinib.

    PubMed

    Mathew, Mohit P; Tan, Elaine; Saeui, Christopher T; Bovonratwet, Patawut; Liu, Lingshu; Bhattacharya, Rahul; Yarema, Kevin J

    2015-03-15

    Metastatic human pancreatic cancer cells (the SW1990 line) that are resistant to the EGFR-targeting tyrosine kinase inhibitor drugs (TKI) erlotinib and gefitinib were treated with 1,3,4-O-Bu3ManNAc, a 'metabolic glycoengineering' drug candidate that increased sialylation by ∼2-fold. Consistent with genetic methods previously used to increase EGFR sialylation, this small molecule reduced EGF binding, EGFR transphosphorylation, and downstream STAT activation. Significantly, co-treatment with both the sugar pharmacophore and the existing TKI drugs resulted in strong synergy, in essence re-sensitizing the SW1990 cells to these drugs. Finally, 1,3,4-O-Bu3ManNAz, which is the azido-modified counterpart to 1,3,4-O-Bu3ManNAc, provided a similar benefit thereby establishing a broad-based foundation to extend a 'metabolic glycoengineering' approach to clinical applications.

  2. Variability in initial nicotine sensitivity due to sex, history of other drug use, and parental smoking.

    PubMed

    Perkins, Kenneth A; Coddington, Sarah B; Karelitz, Joshua L; Jetton, Christopher; Scott, John A; Wilson, Annette S; Lerman, Caryn

    2009-01-01

    Initial sensitivity to nicotine's effects during early exposure to tobacco may relate to dependence vulnerability. We examined the association of initial nicotine sensitivity with individual difference factors of sex, other drug use history (i.e. cross-tolerance or cross-sensitization), and parental smoking status in young adult nonsmokers (N=131). Participants engaged in 4 sessions, the first 3 to assess the dose-response effects of nasal spray nicotine (0, 5, 10 microg/kg) on rewarding, mood, physiological, sensory processing, and performance effects, and the fourth to assess nicotine reinforcement using a choice procedure. Men had greater initial sensitivity than women to some self-reported effects of nicotine related to reward and incentive salience and to impairment in sensory processing, but men and women did not differ on most other effects. Prior marijuana use was associated with greater nicotine reward, nicotine reinforcement was greater in men versus women among those with prior marijuana use, and having parents who smoked was related to increased incentive salience. However, history of other drug use and parental smoking were not otherwise associated with initial nicotine sensitivity. These findings warrant replication with other methods of nicotine administration, especially cigarette smoking, and in more diverse samples of subjects naïve to nicotine. Yet, they suggest that sex differences in initial sensitivity to nicotine reward occur before the onset of dependence. They also suggest that parental smoking may not increase risk of nicotine dependence in offspring by altering initial nicotine sensitivity, and that cross-tolerance between other drugs and nicotine may not be robust in humans.

  3. Modulating cell-to-cell variability and sensitivity to death ligands by co-drugging

    NASA Astrophysics Data System (ADS)

    Flusberg, Deborah A.; Sorger, Peter K.

    2013-06-01

    TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) holds promise as an anti-cancer therapeutic but efficiently induces apoptosis in only a subset of tumor cell lines. Moreover, even in clonal populations of responsive lines, only a fraction of cells dies in response to TRAIL and individual cells exhibit cell-to-cell variability in the timing of cell death. Fractional killing in these cell populations appears to arise not from genetic differences among cells but rather from differences in gene expression states, fluctuations in protein levels and the extent to which TRAIL-induced death or survival pathways become activated. In this study, we ask how cell-to-cell variability manifests in cell types with different sensitivities to TRAIL, as well as how it changes when cells are exposed to combinations of drugs. We show that individual cells that survive treatment with TRAIL can regenerate the sensitivity and death-time distribution of the parental population, demonstrating that fractional killing is a stable property of cell populations. We also show that cell-to-cell variability in the timing and probability of apoptosis in response to treatment can be tuned using combinations of drugs that together increase apoptotic sensitivity compared to treatment with one drug alone. In the case of TRAIL, modulation of cell-to-cell variability by co-drugging appears to involve a reduction in the threshold for mitochondrial outer membrane permeabilization.

  4. Dynamical Model of Drug Accumulation in Bacteria: Sensitivity Analysis and Experimentally Testable Predictions

    PubMed Central

    Vesselinova, Neda; Wall, Michael E.

    2016-01-01

    We present a dynamical model of drug accumulation in bacteria. The model captures key features in experimental time courses on ofloxacin accumulation: initial uptake; two-phase response; and long-term acclimation. In combination with experimental data, the model provides estimates of import and export rates in each phase, the time of entry into the second phase, and the decrease of internal drug during acclimation. Global sensitivity analysis, local sensitivity analysis, and Bayesian sensitivity analysis of the model provide information about the robustness of these estimates, and about the relative importance of different parameters in determining the features of the accumulation time courses in three different bacterial species: Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The results lead to experimentally testable predictions of the effects of membrane permeability, drug efflux and trapping (e.g., by DNA binding) on drug accumulation. A key prediction is that a sudden increase in ofloxacin accumulation in both E. coli and S. aureus is accompanied by a decrease in membrane permeability. PMID:27824914

  5. Thermo-sensitive complex micelles from sodium alginate-graft-poly(N-isopropylacrylamide) for drug release.

    PubMed

    Yu, Nana; Li, Guiying; Gao, Yurong; Jiang, Hua; Tao, Qian

    2016-05-01

    Polymer micelles with environmentally sensitive properties have potential applications in biomedicine. In this paper, thermo-sensitive complex micelles assembled from biocompatible graft copolymers sodium alginate-graft-poly(N-isopropylacrylamide) (SA-g-PNIPAM) and divalent metal ions were prepared for controlled drug release. The polymer micelles had core-corona structure, which was constituted by metal ions (Ba(2+), Zn(2+), Co(2+)) cross-linked sodium alginate as the core and thermo-sensitive PNIPAM chains as the corona. Formation of polymer micelles was determined by Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The polymer micelles were observed as regular spheres with good polydispersity and excellent performance on drug encapsulation and release ability. The cumulative release of 5-fluorouracil (5-FU) from micelles was controlled by pH, ionic strength or temperature of surroundings. The superior properties of sensitive polymer micelles induced by metal ions are expected to be utilized in controlled drug delivery systems.

  6. Rapid Sensitization of Physiological, Neuronal, and Locomotor Effects of Nicotine: Critical Role of Peripheral Drug Actions

    PubMed Central

    Lenoir, Magalie; Tang, Jeremy S.; Woods, Amina S.

    2013-01-01

    Repeated exposure to nicotine and other psychostimulant drugs produces persistent increases in their psychomotor and physiological effects (sensitization), a phenomenon related to the drugs' reinforcing properties and abuse potential. Here we examined the role of peripheral actions of nicotine in nicotine-induced sensitization of centrally mediated physiological parameters (brain, muscle, and skin temperatures), cortical and VTA EEG, neck EMG activity, and locomotion in freely moving rats. Repeated injections of intravenous nicotine (30 μg/kg) induced sensitization of the drug's effects on all these measures. In contrast, repeated injections of the peripherally acting analog of nicotine, nicotine pyrrolidine methiodide (nicotinePM, 30 μg/kg, i.v.) resulted in habituation (tolerance) of the same physiological, neuronal, and behavioral measures. However, after repeated nicotine exposure, acute nicotinePM injections induced nicotine-like physiological responses: powerful cortical and VTA EEG desynchronization, EMG activation, a large brain temperature increase, but weaker hyperlocomotion. Additionally, both the acute locomotor response to nicotine and nicotine-induced locomotor sensitization were attenuated by blockade of peripheral nicotinic receptors by hexamethonium (3 mg/kg, i.v.). These data suggest that the peripheral actions of nicotine, which precede its direct central actions, serve as a conditioned interoceptive cue capable of eliciting nicotine-like physiological and neural responses after repeated nicotine exposure. Thus, by providing a neural signal to the CNS that is repeatedly paired with the direct central effects of nicotine, the drug's peripheral actions play a critical role in the development of nicotine-induced physiological, neural, and behavioral sensitization. PMID:23761889

  7. Validation of a sample pretreatment protocol to convert a drug-sensitive into a drug-tolerant anti-infliximab antibody immunoassay.

    PubMed

    Van Stappen, Thomas; Brouwers, Els; Vermeire, Séverine; Gils, Ann

    2017-02-01

    A meta-analysis revealed that up to 51% of patients treated with infliximab develop anti-drug Abs (ADA) which are associated with loss of response. Detection of ADA is strongly influenced by assay technique since drug-sensitive ADA assays are not able to detect ADA in the presence of drug and therefore underestimate ADA development. In addition, the lack of a calibrator antibody that can be used in a drug-sensitive and drug-tolerant assay hampers an adequate comparison among different assays. Here we present a sample pretreatment protocol to convert the bridging assay, originally developed as a drug-sensitive assay, into a drug-tolerant assay, allowing use of the same assay and calibrator antibody MA-IFX10F9. Using the sample pretreatment protocol, the bridging assay detects antibodies towards infliximab in samples containing up to 5-fold infliximab over anti-infliximab. Analysis of consecutive serum samples from infliximab treated patients revealed that the drug-tolerant assay detects ADA development up to 40 weeks earlier compared to the drug-sensitive assay. In conclusion, the sample pretreatment protocol can be implemented in various assay formats and allows determination of ADA in the presence of drug, providing the possibility for early treatment optimization. Copyright © 2016 John Wiley & Sons, Ltd.

  8. pH-sensitive polymeric nanoparticles to improve oral bioavailability of peptide/protein drugs and poorly water-soluble drugs.

    PubMed

    Wang, Xue-Qing; Zhang, Qiang

    2012-10-01

    pH-sensitive polymeric nanoparticles are promising for oral drug delivery, especially for peptide/protein drugs and poorly water-soluble medicines. This review describes current status of pH-sensitive polymeric nanoparticles for oral drug delivery and introduces the mechanisms of drug release from them as well as possible reasons for absorption improvement, with emphasis on our contribution to this field. pH-sensitive polymeric nanoparticles are prepared mainly with polyanions, polycations, their mixtures or cross-linked polymers. The mechanisms of drug release are the result of carriers' dissolution, swelling or both of them at specific pH. The possible reasons for improvement of oral bioavailability include the following: improve drug stability, enhance mucoadhesion, prolong resident time in GI tract, ameliorate intestinal permeability and increase saturation solubility and dissolution rate for poorly water-soluble drugs. As for the advantages of pH-sensitive nanoparticles over conventional nanoparticles, we conclude that (1) most carriers used are enteric-coating materials and their safety has been approved. (2) The rapid dissolution or swelling of carriers at specific pH results in quick drug release and high drug concentration gradient, which is helpful for absorption. (3) At the specific pH carriers dissolve or swell, and the bioadhesion of carriers to mucosa becomes high because nanoparticles turn from solid to gel, which can facilitate drug absorption.

  9. In vivo and in vitro sensitivity of Trichomonas gallinae to some nitroimidazole drugs.

    PubMed

    Munoz, E; Castella, J; Gutierrez, J F

    1998-08-31

    A study was carried out in order to establish the in vivo efficacy of two nitroimidazole drugs against the flagellate Trichomonas gallinae. The results obtained showed a high proportion of therapeutic failures. Thus, carnidazole and dimetridazole failed to eliminate infection in 13 of 17 and 20 of 21 racing pigeons, respectively. The in vitro susceptibility of four T. gallinae isolates to five nitroimidazolic drugs, that is, carnidazole, dimetridazole, metronidazole, ornidazole and ronidazole, was also determined. Minimal lethal concentrations (MLCs) of these drugs were obtained. One of the isolates tested had already proved to be resistant in the first in vivo tests, while the other three had been obtained from wild birds. We were able to confirm in vitro the resistance of the racing pigeon isolate to all the nitroimidazole drugs tested. For carnidazole, dimetridazole, metronidazole and ornidazole the MLC ranged between 93.75-500 microg ml. Although ronidazole showed a greater potency than the other nitroimidazole derivatives against this isolate (MLC: 15.62-31.25 microg ml), 8-22 times more drug was necessary for efficacy against this isolate compared to the others. These other three parasite isolates proved to be sensitive to the five drugs tested (MLC: 0.97-7.81 microg ml).

  10. Variation in topoisomerase I gene copy number as a mechanism for intrinsic drug sensitivity.

    PubMed Central

    McLeod, H. L.; Keith, W. N.

    1996-01-01

    DNA topoisomerase I (topo I) is the principle target for camptothecin and its derivatives such as SN38. Levels of topo I expression vary widely between and within tumour types and the basis for this is poorly understood. We have used fluorescence in situ hybridisation to detect the topo I locus in a panel of breast and colon cancer cell lines. This approach has identified a range of topo I gene copies from 1 to 6 between the cell lines as a result of DNA amplification, polysomy and isochromosome formation. Topo I gene copy number was highly correlated with topo I expression, (rs = 0.92), and inversely correlated to sensitivity to a 1 h exposure to SN38 (rs = -0.904). This illustrates the significant impact of altered topo I gene copy number on intrinsic drug sensitivity and influences potential mechanisms for acquisition of drug resistance. Images Figure 1 Figure 2 PMID:8761363

  11. Discovery of New Monocarbonyl Ligustrazine-Curcumin Hybrids for Intervention of Drug-Sensitive and Drug-Resistant Lung Cancer.

    PubMed

    Ai, Yong; Zhu, Bin; Ren, Caiping; Kang, Fenghua; Li, Jinlong; Huang, Zhangjian; Lai, Yisheng; Peng, Sixun; Ding, Ke; Tian, Jide; Zhang, Yihua

    2016-03-10

    The elevation of oxidative stress preferentially in cancer cells by inhibiting thioredoxin reductase (TrxR) and/or enhancing reactive oxygen species (ROS) production has emerged as an effective strategy for selectively targeting cancer cells. In this study, we designed and synthesized 21 ligustrazine-curcumin hybrids (10a-u). Biological evaluation indicated that the most active compound 10d significantly inhibited the proliferation of drug-sensitive (A549, SPC-A-1, LTEP-G-2) and drug-resistant (A549/DDP) lung cancer cells but had little effect on nontumor lung epithelial-like cells (HBE). Furthermore, 10d suppressed the TrxR/Trx system and promoted intracellular ROS accumulation and cancer cell apoptosis. Additionally, 10d inhibited the NF-κB, AKT, and ERK signaling, P-gp-mediated efflux of rhodamine 123, P-gp ATPase activity, and P-gp expression in A549/DDP cells. Finally, 10d repressed the growth of implanted human drug-resistant lung cancer in mice. Together, 10d acts a novel TrxR inhibitor and may be a promising candidate for intervention of lung cancer.

  12. Genome-wide barcoded transposon screen for cancer drug sensitivity in haploid mouse embryonic stem cells

    PubMed Central

    Pettitt, Stephen J.; Krastev, Dragomir B.; Pemberton, Helen N.; Fontebasso, Yari; Frankum, Jessica; Rehman, Farah L.; Brough, Rachel; Song, Feifei; Bajrami, Ilirjana; Rafiq, Rumana; Wallberg, Fredrik; Kozarewa, Iwanka; Fenwick, Kerry; Armisen-Garrido, Javier; Swain, Amanda; Gulati, Aditi; Campbell, James; Ashworth, Alan; Lord, Christopher J.

    2017-01-01

    We describe a screen for cellular response to drugs that makes use of haploid embryonic stem cells. We generated ten libraries of mutants with piggyBac gene trap transposon integrations, totalling approximately 100,000 mutant clones. Random barcode sequences were inserted into the transposon vector to allow the number of cells bearing each insertion to be measured by amplifying and sequencing the barcodes. These barcodes were associated with their integration sites by inverse PCR. We exposed these libraries to commonly used cancer drugs and profiled changes in barcode abundance by Ion Torrent sequencing in order to identify mutations that conferred sensitivity. Drugs tested included conventional chemotherapeutics as well as targeted inhibitors of topoisomerases, poly(ADP-ribose) polymerase (PARP), Hsp90 and WEE1. PMID:28248920

  13. Systematic identification of genomic markers of drug sensitivity in cancer cells.

    PubMed

    Garnett, Mathew J; Edelman, Elena J; Heidorn, Sonja J; Greenman, Chris D; Dastur, Anahita; Lau, King Wai; Greninger, Patricia; Thompson, I Richard; Luo, Xi; Soares, Jorge; Liu, Qingsong; Iorio, Francesco; Surdez, Didier; Chen, Li; Milano, Randy J; Bignell, Graham R; Tam, Ah T; Davies, Helen; Stevenson, Jesse A; Barthorpe, Syd; Lutz, Stephen R; Kogera, Fiona; Lawrence, Karl; McLaren-Douglas, Anne; Mitropoulos, Xeni; Mironenko, Tatiana; Thi, Helen; Richardson, Laura; Zhou, Wenjun; Jewitt, Frances; Zhang, Tinghu; O'Brien, Patrick; Boisvert, Jessica L; Price, Stacey; Hur, Wooyoung; Yang, Wanjuan; Deng, Xianming; Butler, Adam; Choi, Hwan Geun; Chang, Jae Won; Baselga, Jose; Stamenkovic, Ivan; Engelman, Jeffrey A; Sharma, Sreenath V; Delattre, Olivier; Saez-Rodriguez, Julio; Gray, Nathanael S; Settleman, Jeffrey; Futreal, P Andrew; Haber, Daniel A; Stratton, Michael R; Ramaswamy, Sridhar; McDermott, Ultan; Benes, Cyril H

    2012-03-28

    Clinical responses to anticancer therapies are often restricted to a subset of patients. In some cases, mutated cancer genes are potent biomarkers for responses to targeted agents. Here, to uncover new biomarkers of sensitivity and resistance to cancer therapeutics, we screened a panel of several hundred cancer cell lines--which represent much of the tissue-type and genetic diversity of human cancers--with 130 drugs under clinical and preclinical investigation. In aggregate, we found that mutated cancer genes were associated with cellular response to most currently available cancer drugs. Classic oncogene addiction paradigms were modified by additional tissue-specific or expression biomarkers, and some frequently mutated genes were associated with sensitivity to a broad range of therapeutic agents. Unexpected relationships were revealed, including the marked sensitivity of Ewing's sarcoma cells harbouring the EWS (also known as EWSR1)-FLI1 gene translocation to poly(ADP-ribose) polymerase (PARP) inhibitors. By linking drug activity to the functional complexity of cancer genomes, systematic pharmacogenomic profiling in cancer cell lines provides a powerful biomarker discovery platform to guide rational cancer therapeutic strategies.

  14. Enhancement of drug sensitivity of human malignancies by epidermal growth factor.

    PubMed Central

    Kröning, R.; Jones, J. A.; Hom, D. K.; Chuang, C. C.; Sanga, R.; Los, G.; Howell, S. B.; Christen, R. D.

    1995-01-01

    We have previously shown that epidermal growth factor (EGF) enhances the in vitro and in vivo sensitivity of human ovarian carcinoma 2008 cells to cisplatin. EGF was found to enhance selectively the in vivo toxicity of cisplatin to 2008 cell xenografts without altering the toxicity of cisplatin to non-malignant target tissues such as the kidney or bone marrow. We now show that recombinant human EGF (rhEGF) enhances the cisplatin sensitivity of cell lines representative of many other types of malignancies in addition to ovarian carcinoma, including cancers of the head and neck, cervix, colon, pancreas and prostate, as well as non-small-cell carcinoma of the lung. In addition, rhEGF was found to sensitise cells to other platinum-containing drugs and several other classes of chemotherapeutic agents. rhEGF sensitised 2008 cells not only to cisplatin, but also to carboplatin and tetraplatin, as well as taxol, melphalan and 5-fluorouracil. We conclude that modulation of drug sensitivity by rhEGF is observed in cell lines representative of many human malignancies and for multiple classes of chemotherapeutic agents, indicating that it alters one or more components of the cellular damage response that are both common between cell lines and classes of drugs and fundamental to survival. Images Figure 2 PMID:7669570

  15. The Cancer Cell Line Encyclopedia enables predictive modelling of anticancer drug sensitivity.

    PubMed

    Barretina, Jordi; Caponigro, Giordano; Stransky, Nicolas; Venkatesan, Kavitha; Margolin, Adam A; Kim, Sungjoon; Wilson, Christopher J; Lehár, Joseph; Kryukov, Gregory V; Sonkin, Dmitriy; Reddy, Anupama; Liu, Manway; Murray, Lauren; Berger, Michael F; Monahan, John E; Morais, Paula; Meltzer, Jodi; Korejwa, Adam; Jané-Valbuena, Judit; Mapa, Felipa A; Thibault, Joseph; Bric-Furlong, Eva; Raman, Pichai; Shipway, Aaron; Engels, Ingo H; Cheng, Jill; Yu, Guoying K; Yu, Jianjun; Aspesi, Peter; de Silva, Melanie; Jagtap, Kalpana; Jones, Michael D; Wang, Li; Hatton, Charles; Palescandolo, Emanuele; Gupta, Supriya; Mahan, Scott; Sougnez, Carrie; Onofrio, Robert C; Liefeld, Ted; MacConaill, Laura; Winckler, Wendy; Reich, Michael; Li, Nanxin; Mesirov, Jill P; Gabriel, Stacey B; Getz, Gad; Ardlie, Kristin; Chan, Vivien; Myer, Vic E; Weber, Barbara L; Porter, Jeff; Warmuth, Markus; Finan, Peter; Harris, Jennifer L; Meyerson, Matthew; Golub, Todd R; Morrissey, Michael P; Sellers, William R; Schlegel, Robert; Garraway, Levi A

    2012-03-28

    The systematic translation of cancer genomic data into knowledge of tumour biology and therapeutic possibilities remains challenging. Such efforts should be greatly aided by robust preclinical model systems that reflect the genomic diversity of human cancers and for which detailed genetic and pharmacological annotation is available. Here we describe the Cancer Cell Line Encyclopedia (CCLE): a compilation of gene expression, chromosomal copy number and massively parallel sequencing data from 947 human cancer cell lines. When coupled with pharmacological profiles for 24 anticancer drugs across 479 of the cell lines, this collection allowed identification of genetic, lineage, and gene-expression-based predictors of drug sensitivity. In addition to known predictors, we found that plasma cell lineage correlated with sensitivity to IGF1 receptor inhibitors; AHR expression was associated with MEK inhibitor efficacy in NRAS-mutant lines; and SLFN11 expression predicted sensitivity to topoisomerase inhibitors. Together, our results indicate that large, annotated cell-line collections may help to enable preclinical stratification schemata for anticancer agents. The generation of genetic predictions of drug response in the preclinical setting and their incorporation into cancer clinical trial design could speed the emergence of 'personalized' therapeutic regimens.

  16. Nonsteroidal anti-inflammatory drug sensitizes Mycobacterium tuberculosis to endogenous and exogenous antimicrobials

    PubMed Central

    Gold, Ben; Pingle, Maneesh; Brickner, Steven J.; Shah, Nilesh; Roberts, Julia; Rundell, Mark; Bracken, W. Clay; Warrier, Thulasi; Somersan, Selin; Venugopal, Aditya; Darby, Crystal; Jiang, Xiuju; Warren, J. David; Fernandez, Joseph; Ouerfelli, Ouathek; Nuermberger, Eric L.; Cunningham-Bussel, Amy; Rath, Poonam; Chidawanyika, Tamutenda; Deng, Haiteng; Realubit, Ronald; Glickman, J. Fraser; Nathan, Carl F.

    2012-01-01

    Existing drugs are slow to eradicate Mycobacterium tuberculosis (Mtb) in patients and have failed to control tuberculosis globally. One reason may be that host conditions impair Mtb’s replication, reducing its sensitivity to most antiinfectives. We devised a high-throughput screen for compounds that kill Mtb when its replication has been halted by reactive nitrogen intermediates (RNIs), acid, hypoxia, and a fatty acid carbon source. At concentrations routinely achieved in human blood, oxyphenbutazone (OPB), an inexpensive anti-inflammatory drug, was selectively mycobactericidal to nonreplicating (NR) Mtb. Its cidal activity depended on mild acid and was augmented by RNIs and fatty acid. Acid and RNIs fostered OPB’s 4-hydroxylation. The resultant 4-butyl-4-hydroxy-1-(4-hydroxyphenyl)-2-phenylpyrazolidine-3,5-dione (4-OH-OPB) killed both replicating and NR Mtb, including Mtb resistant to standard drugs. 4-OH-OPB depleted flavins and formed covalent adducts with N-acetyl-cysteine and mycothiol. 4-OH-OPB killed Mtb synergistically with oxidants and several antituberculosis drugs. Thus, conditions that block Mtb’s replication modify OPB and enhance its cidal action. Modified OPB kills both replicating and NR Mtb and sensitizes both to host-derived and medicinal antimycobacterial agents. PMID:23012453

  17. Formulation and characterization of sustained release dosage form of moisture sensitive drug

    PubMed Central

    Patel, Priya; Dave, Abhishek; Vasava, Amit; Patel, Paresh

    2015-01-01

    Objective: The purpose of this study was to prepare sustained release tablet of moisture sensitive drug like Ranitidine Hydrochloride for treatment of gastroesophageal reflux disease along with the improvement of moisture stability to get better therapeutic efficacy. Materials and Methods: Pan coating technique was used for coating of the tablet. Film coating was done using Eudragit RLPO and Eugragit EPO as coating polymer. 32 full factorial design was applied for optimization purpose, and 9 runs were conducted. In that Eudragit RLPO and Eudragit EPO taken as an independent variables and moisture gain and Cummulative Drug Release (CDR) were taken as dependent variables. Drug and excipient compatibility was done using differential scanning calorimetry and Fourier transform infrared spectroscopy study. The tablet was evaluated for precompression parameter and all postcompression parameter. Stability study was carried out at room temperature (30°C ± 2°C/65% ± 5% relative humidity). Final formulation was compared with marketed formulation RANTEC 300. Result: Tablets were passing out all precompression parameter along with postcompression parameter. Stability study shows that the parameter such as hardness, friability, and dissolution are in the range. Hence, there is no significant change shown after stability study. Our final formulation was compared with marketed formulation RANTEC 300 and result demonstrates that our final formulation have less moisture gain and give release up to 12 h. Conclusion: The result of present study demonstrates that final formulation has less moisture gain and getting desired CDR for sustained release of drug. On the basis of all study, it was concluded that the tablet was coated by combination of Eudragit RLPO 10% and Eudragit EPO 10% give better result. This formation provided promising approach for the drug release up to 12 h for moisture sensitive drug like ranitidine hydrochloride. PMID:25838994

  18. Keto-Mycolic Acid-Dependent Pellicle Formation Confers Tolerance to Drug-Sensitive Mycobacterium tuberculosis

    PubMed Central

    Sambandan, Dhinakaran; Dao, Dee N.; Weinrick, Brian C.; Vilchèze, Catherine; Gurcha, Sudagar S.; Ojha, Anil; Kremer, Laurent; Besra, Gurdyal S.; Hatfull, Graham F.; Jacobs, William R.

    2013-01-01

    ABSTRACT The chronic nature of tuberculosis (TB), its requirement of long duration of treatment, its ability to evade immune intervention, and its propensity to relapse after drug treatment is discontinued are reminiscent of other chronic, biofilm-associated bacterial diseases. Historically, Mycobacterium tuberculosis was grown as a pellicle, a biofilm-like structure, at the liquid-air interface in a variety of synthetic media. Notably, the most widely administered human vaccine, BCG, is grown as a pellicle for vaccine production. However, the molecular requirements for this growth remain ill defined. Here, we demonstrate that keto-mycolic acids (keto-MA) are essential for pellicle growth, and mutants lacking in or depleted of this MA species are unable to form a pellicle. We investigated the role of the pellicle biofilm in the reduction of antibiotic sensitivity known as drug tolerance using the pellicle-defective ΔmmaA4 mutant strain. We discovered that the ΔmmaA4 mutant, which is both pellicle defective and highly sensitive to rifampicin (RIF) under planktonic growth, when incorporated within the wild-type pellicle biofilm, was protected from the bactericidal activity of RIF. The observation that growth within the M. tuberculosis pellicle biofilm can confer drug tolerance to a drug-hypersensitive strain suggests that identifying molecular requirements for pellicle growth could lead to development of novel interventions against mycobacterial infections. Our findings also suggest that a class of drugs that can disrupt M. tuberculosis biofilm formation, when used in conjunction with conventional antibiotics, has the potential to overcome drug tolerance. PMID:23653446

  19. Design of an Inflammation-Sensitive Polyelectrolyte-Based Topical Drug Delivery System for Arthritis.

    PubMed

    Bijukumar, Divya; Choonara, Yahya E; Murugan, Karmani; Choonara, Bibi Fatima; Kumar, Pradeep; du Toit, Lisa C; Pillay, Viness

    2016-10-01

    The most successful treatment strategy for arthritis is intra-articular injections that are costly and have reduced patient compliance. The purpose of the current study was to develop an inflammation-sensitive system for topical drug administration. Multi-macromolecular alginate-hyaluronic acid-chitosan (A-H-C) polyelectrolyte complex nanoparticles, loaded with indomethacin were developed employing pre-gel and post-gel techniques in the presence of dodecyl-L-pyroglutamate (DLP). In addition to in vitro studies, in silico simulations were performed to affirm and associate the molecular interactions inherent to the formulation of core all-natural multi-component biopolymeric architectures composed of an anionic (alginate), a cationic (chitosan), and an amphi-ionic polyelectrolytic (hyaluronic acid) macromolecule. The results demonstrated that DLP significantly influenced the size of the synthesized nanoparticles. Drug-content analysis revealed higher encapsulation efficiency (77.3%) in the presence of DLP, irrespective of the techniques used. Moreover, in vitro drug release studies showed that indomethacin release from the nanosystem was significantly improved (98%) in Fenton's reagent. Drug permeation across a cellulose membrane using a Franz diffusion cell system showed an initial surge flux (0.125 mg/cm(-2)/h), followed by sustained release of indomethacin for the post-gel nanoparticles revealing its effective skin permeation efficiency. In conclusion, the study presents novel nanoparticles which could effectively encapsulate and deliver hydrophobic drugs to the target site, particularly for arthritis.

  20. Sonochemically synthesized biocompatible zirconium phosphate nanoparticles for pH sensitive drug delivery application.

    PubMed

    Kalita, Himani; Prashanth Kumar, B N; Konar, Suraj; Tantubay, Sangeeta; Kr Mahto, Madhusudan; Mandal, Mahitosh; Pathak, Amita

    2016-03-01

    The present work reports the synthesis of biocompatible zirconium phosphate (ZP) nanoparticles as nanocarrier for drug delivery application. The ZP nanoparticles were synthesized via a simple sonochemical method in the presence of cetyltrimethylammonium bromide and their efficacy for the delivery of drugs has been tested through various in-vitro experiments. The particle size and BET surface area of the nanoparticles were found to be ~48 nm and 206.51 m(2)/g respectively. The conventional MTT assay and cellular localization studies of the particles, performed on MDA-MB-231 cell lines, demonstrate their excellent biocompatibility and cellular internalization behavior. The loading of curcumin, an antitumor drug, onto the ZP nanoparticles shows the rapid drug uptake ability of the particles, while the drug release study, performed at two different pH values (at 7.4 and 5) depicts pH sensitive release-profile. The MTT assay and cellular localization studies revealed higher cellular inhibition and better bioavailability of the nanoformulated curcumin compared to free curcumin.

  1. RNA-seq reveals determinants of sensitivity to chemotherapy drugs in esophageal carcinoma cells.

    PubMed

    Yang, Li-Xin; Li, Bai-Ling; Liu, Xiao-Hong; Yuan, Yang; Lu, Chao-Jing; Chen, Rui; Zhao, Jian

    2014-01-01

    Chemotherapy remains the mainstay of treatment for patients with incurable disease of esophageal carcinoma. Most patients respond poorly to chemotherapy, it is necessary to figure out biomarkers for chemotherapy sensitivity or resistance to perform the individualized therapy. In present work, the sensitivities of two ESCC cell lines to 9 chemotherapy drugs were identified and the transcriptome of these two cell lines were investigated by RNA-seq, the correlation between the sensitivity to drugs and expression of some genes was attempted to construct. Eca-1 was more resistant to most of the chemotherapy drugs than Eca-109 cell line. RNA-seq results showed that there is dramatic difference in the basal expression between these two ESCC cell lines. Pathway analysis demonstrated that these differentially expressed genes were mainly enriched in Gαi signaling, calcium signaling, cAMP-mediated signaling, G-protein coupled receptor signaling and actin cytoskeleton signaling pathways. The molecules in Gαi signaling (ADCY1 and SSTR3) and actin cytoskeleton signaling (MYH6 and MYH7) were highly expressed in multidrug-resistant Eca-1 cells, which were validated by quantitative PCR. Activation of these two pathways results in the upregulation of downstream signaling, PKA signaling and Src-STAT3, and downregulation of RAF-ERK signaling, which was validated by immunoblotting experiments. Our work proposed that activation of Gαi signaling or actin cytoskeleton signaling may confer ESCC cells resistance to most chemotherapy drugs. Our work might provide potential biomarkers and therapeutic targets for treatment of EC patients.

  2. Hepatic drug metabolizing profile of Flinders Sensitive Line rat model of depression.

    PubMed

    Kotsovolou, Olga; Ingelman-Sundberg, Magnus; Lang, Matti A; Marselos, Marios; Overstreet, David H; Papadopoulou-Daifoti, Zoi; Johanson, Inger; Fotopoulos, Andrew; Konstandi, Maria

    2010-08-16

    The Flinders Sensitive Line (FSL) rat model of depression exhibits some behavioral, neurochemical, and pharmacological features that have been reported in depressed patients and has been very effective in screening antidepressants. Major factor that determines the effectiveness and toxicity of a drug is the drug metabolizing capacity of the liver. Therefore, in order to discriminate possible differentiation in the hepatic drug metabolism between FSL rats and Sprague-Dawley (SD) controls, their hepatic metabolic profile was investigated in this study. The data showed decreased glutathione (GSH) content and glutathione S-transferase (GST) activity and lower expression of certain major CYP enzymes, including the CYP2B1, CYP2C11 and CYP2D1 in FSL rats compared to SD controls. In contrast, p-nitrophenol hydroxylase (PNP), 7-ethoxyresorufin-O-dealkylase (EROD) and 16alpha-testosterone hydroxylase activities were higher in FSL rats. Interestingly, the wide spread environmental pollutant benzo(alpha)pyrene (B(alpha)P) induced CYP1A1, CYP1A2, CYP2B1/2 and ALDH3c at a lesser extend in FSL than in SD rats, whereas the antidepressant mirtazapine (MIRT) up-regulated CYP1A1/2, CYP2C11, CYP2D1, CYP2E1 and CYP3A1/2, mainly, in FSL rats. The drug also further increased ALDH3c whereas suppressed GSH content in B(alpha)P-exposed FSL rats. In conclusion, several key enzymes of the hepatic biotransformation machinery are differentially expressed in FSL than in SD rats, a condition that may influence the outcome of drug therapy. The MIRT-induced up-regulation of several drug-metabolizing enzymes indicates the critical role of antidepressant treatment that should be always taken into account in the designing of treatment and interpretation of insufficient pharmacotherapy or drug toxicity.

  3. The wisdom of crowds and the repurposing of artesunate as an anticancer drug

    PubMed Central

    Augustin, Yolanda; Krishna, Sanjeev; Kumar, Devinder; Pantziarka, Pan

    2015-01-01

    Artesunate, a semi-synthetic and water-soluble artemisinin-derivative used as an anti-malarial agent, has attracted the attention of cancer researchers due to a broad range of anti-cancer activity including anti-angiogenic, immunomodulatory and treatment-sensitisation effects. In addition to pre-clinical evidence in a range of cancers, a recently completed randomised blinded trial in colorectal cancer has provided a positive signal for further clinical investigation. Used perioperatively artesunate appears to reduce the rate of disease recurrence - and the Neo-Art trial, a larger Phase II RCT, is seeking to confirm this positive effect. However, artesunate is a generic medication, and as with other trials of repurposed drugs, the Neo-Art trial does not have commercial sponsorship. In an innovative move, the trial is seeking funds directly from members of the public via a crowd-funding strategy that may have resonance beyond this single trial. PMID:26557887

  4. Active site similarity between human and Plasmodium falciparum phosphodiesterases: considerations for antimalarial drug design

    NASA Astrophysics Data System (ADS)

    Howard, Brittany L.; Thompson, Philip E.; Manallack, David T.

    2011-08-01

    The similarity between Plasmodium falciparum phosphodiesterase enzymes ( PfPDEs) and their human counterparts have been examined and human PDE9A was found to be a suitable template for the construction of homology models for each of the four PfPDE isoforms. In contrast, the architecture of the active sites of each model was most similar to human PDE1. Molecular docking was able to model cyclic guanosine monophosphate (cGMP) substrate binding in each case but a docking mode supporting cyclic adenosine monophosphate (cAMP) binding could not be found. Anticipating the potential of PfPDE inhibitors as anti-malarial drugs, a range of reported PDE inhibitors including zaprinast and sildenafil were docked into the model of PfPDEα. The results were consistent with their reported biological activities, and the potential of PDE1/9 inhibitor analogues was also supported by docking.

  5. Sensitive Determination of Sertraline in Commercial Drugs and Its Stability Check in Simulated Gastric Juice.

    PubMed

    Koçoğlu, Elif Seda; Bakırdere, Sezgin; Keyf, Seyfullah

    2016-11-01

    A sensitive analytical method was developed for the determination of sertraline in commercial drug samples by using GC-MS. The selected-ion monitoring mode was used at the most sensitive m/z 274 to obtain a lower detection limit. LOD/LOQ values were obtained as 1.6/5.4 ng/mL for sertraline under the optimum conditions. The calibration plot was linear between 5.0 and 2000 ng/mL with the correlation coefficient of 0.9999. The validated method was successfully applied to three different brands of drug samples for both qualitative and quantitative measurement of sertraline. In this experiment, four replicate extractions were performed for each brand, and the results were compared to the values written on the labels of the drug brands. Spiking experiments were also performed to check the effect of the matrixes on the determination, and it was observed that there was no shift in the retention time of the analyte. In addition, simulated gastric juice experiments were performed to check the stability of sertraline in the stomach for 240 min, and it was observed that there was no change in the structure of the analyte.

  6. Polydopamine-based surface modification of mesoporous silica nanoparticles as pH-sensitive drug delivery vehicles for cancer therapy.

    PubMed

    Chang, Danfeng; Gao, Yongfeng; Wang, Lijun; Liu, Gan; Chen, Yuhan; Wang, Teng; Tao, Wei; Mei, Lin; Huang, Laiqiang; Zeng, Xiaowei

    2016-02-01

    A novel pH-sensitive drug delivery system of mesoporous silica nanoparticles (MSNs) which were modified by polydopamine (PDA) for controlled release of cationic amphiphilic drug desipramine (DES) was prepared. MSNs-DES-PDA were characterized in terms of size, size distribution, surface morphology, BET surface area, mesoporous size and pore volume, drug loading content and in vitro drug release profile. MSNs-DES-PDA had high drug loading content and pH sensitivity. The DES release profiles of MSNs-DES and MSNs-DES-PDA were totally different, and the drug release of MSNs-DES-PDA accelerated with increasing acidity. MSNs-DES-PDA can be internalized into cells. In vitro experiments demonstrated that MSNs-DES-PDA had higher cytotoxicity and inhibitory effects on acid sphingomyelinase than those of free DES. This drug delivery system was beneficial for controlled release and cancer therapy.

  7. Effects of hiking at altitude on body composition and insulin sensitivity in recovering drug addicts.

    PubMed

    Lee, Wen-Chih; Chen, Jin-Jong; Hunt, Desmond D; Hou, Chien-Wen; Lai, Yu-Chiang; Lin, Fang-Ching; Chen, Chung-Yu; Lin, Ching-Hung; Liao, Yi-Hung; Kuo, Chia-Hua

    2004-10-01

    In the current study individuals with a history of drug abuse (users of heroin, cocaine, or amphetamine) displayed a 13-100% increase in body weight (self-reported) and exhibited a trend toward insulin resistance. Therefore, we investigated the effects of long-term altitude hiking on insulin sensitivity in this special population. Nine males recovering from drug addiction (ex-addicts) (age 28.7 +/- 1.3 years) and 17 control subjects (age 29 +/- 1.1 years) voluntarily participated in a 25-day hiking activity (altitude 2200-3800 M). On the 25th day of hiking, oral glucose tolerance test (OGTT), insulin response, lean body mass, fat mass, and waist-to-hip ratio (WHR) were measured in all subjects. After the altitude expedition, insulin levels during the OGTT in ex-addicts were similar to controls, suggesting that insulin sensitivity in this special population was normalized by long-term altitude activity. Along with improvements in insulin sensitivity, a significant reduction in WHR, but small increase in lean body mass, was observed. Twenty-five days of altitude activity significantly reverses hyperinsulinemia in the ex-addicts and this improvement appears to be partially associated with the reduction in central fatness.

  8. Light-sensitive intelligent drug delivery systems of coumarin-modified mesoporous bioactive glass.

    PubMed

    Lin, H-M; Wang, W-K; Hsiung, P-A; Shyu, S-G

    2010-08-01

    Functionalized mesoporous bioactive glasses (MBG) with photoactive coumarin demonstrates photo-responsive dimerization resulting in reversible gate operation. Coumarin-modified MBG was used as a drug delivery carrier to investigate drug storage/release characteristics using phenanthrene as a model drug. Irradiation with UV light (>310 nm) induced photo-dimerization of the coumarin-modified MBG, which led to the pores' closing with cyclobutane dimers and trapping of the guest phenanthrene in the mesopores. However, irradiating the dimerized-coumarin-modified MBG with shorter wavelength UV light (approximately 250 nm) regenerates the coumarin monomer derivative by the photo-cleavage of cyclobutane dimers, such that trapped guest molecules are released from the mesopores. The structural, morphological, textural and optical properties are well characterized by X-ray diffraction, transmission electron microscopy, N(2) adsorption/desorption, and UV-visible spectroscopy. The results reveal that the MBG exhibits the typical ordered characteristics of the hexagonal mesostructure. The system demonstrates great potential in light-sensitive intelligent drug delivery systems and disease therapy fields.

  9. [Insulin sensitizer--anti-diabetic drugs, metformin and pioglitazone that can improve insulin resistance].

    PubMed

    Korenaga, Masaaki; Kawaguchi, Koutaro; Korenaga, Keiko; Uchida, Kouichi; Sakaida, Iso

    2006-06-01

    Nonalcoholic steatohepatitis (NASH), which is considered the hepatic manifestation of the metabolic syndrome is an increasingly cause of chronic liver disease in Japan. NASH is finally lead to liver cirrhosis and hepatocellular carcinoma as viral hepatitis, therefore, medical treatment should be considered, when NASH occurs. Treatment of patients with metabolic syndrome has been focused on the management of associated conditions such as obesity, hyperlipidemia, hypertension and hyperinsulinemia. Insulin resistance, that could accelerate liver inflammation and fibrosis by up-regulation of TNFa seems to be most important factor in many cases of NASH. The insulin-sensitizing drugs, which were biguanides (metformin) and thiazolidinediones (pioglitazone) have been shown to correct not only insulin resistance but also steatosis and inflammation in the liver. Metformin and pioglitazone might be useful drugs against NASH, however further investigations were needed.

  10. Temperature-sensitive hydrogels with SiO2-Au nanoshells for controlled drug delivery.

    PubMed

    Bikram, Malavosklish; Gobin, Andre M; Whitmire, Rachel E; West, Jennifer L

    2007-11-20

    Silica-gold (SiO(2)-Au) nanoshells are a new class of nanoparticles that consist of a silica dielectric core that is surrounded by a gold shell. These nanoshells are unique because their peak extinctions are very easily tunable over a wide range of wavelengths particularly in the near infrared (IR) region of the spectrum. Light in this region is transmitted through tissue with relatively little attenuation due to absorption. In addition, irradiation of SiO(2)-Au nanoshells at their peak extinction coefficient results in the conversion of light to heat energy that produces a local rise in temperature. Thus, to develop a photothermal modulated drug delivery system, we have fabricated nanoshell-composite hydrogels in which SiO(2)-Au nanoshells of varying concentrations have been embedded within temperature-sensitive hydrogels, for the purpose of initiating a temperature change with light. N-isopropylacrylamide-co-acrylamide (NIPAAm-co-AAm) hydrogels are temperature-sensitive hydrogels that were fabricated to exhibit a lower critical solution temperature (LCST) slightly above body temperature. The resulting composite hydrogels had the extinction spectrum of the SiO(2)-Au nanoshells in which the hydrogels collapsed reversibly in response to temperature (50 degrees C) and laser irradiation. The degree of collapse of the hydrogels was controlled by the laser fluence as well as the concentration of SiO(2)-Au nanoshells. Modulated drug delivery profiles for methylene blue, insulin, and lysozyme were achieved by irradiation of the drug-loaded nanoshell-composite hydrogels, which showed that drug release was dependent upon the molecular weight of the therapeutic molecule.

  11. Hydroxychloroquine in polymorphic light eruption: a controlled trial with drug and visual sensitivity monitoring.

    PubMed

    Murphy, G M; Hawk, J L; Magnus, I A

    1987-03-01

    A double-blind controlled trial of oral hydroxychloroquine (HC) treatment in polymorphic light eruption (PLE) was completed in 13 patients on active treatment and 15 on placebo during June, July and August 1982. HC dose was 400 mg daily for the first month and 200 mg daily thereafter. Exposure to ambient solar ultraviolet radiation (UVR) was monitored throughout the trial by polysulphone film lapel badges. Patients scored their symptoms on a visual analogue scale. Drug concentration was monitored in plasma and hair, and oculotoxicity was assessed by visual contrast sensitivity. Moderate clinical improvement occurred, associated with a statistically significant improvement in skin rash (P less than 0.01).

  12. Phase synchronization analysis of voltage-sensitive dye imaging during drug-induced epileptic seizures.

    NASA Astrophysics Data System (ADS)

    Takeshita, Daisuke; Tsytsarev, Vassiliy; Bahar, Sonya

    2008-03-01

    Epileptic seizures are generally held to result from excess and synchronized neural activity. However, recent studies have suggested that this is not necessarily the case. We investigate how the spatiotemporal pattern of synchronization changes during drug-induced in vivo neocortical seizures in rats. Epileptic seizures are caused by the potassium channel blocker 4-aminopyridine, which is often used in experiments to induce epileptic seizures. In our experiments, the neocortex is stained with the voltage-sensitive dye RH-1691. The intensity changes in dye fluorescence are measured by a CCD camera and are consistent with the signal from local field potential recording. We apply phase synchronization analysis to the voltage-sensitive dye signals from pairs of pixels in order to investigate the degree to which synchronization occurs, and how spatial patterns of synchrony may change, during the course of the seizure. Our preliminary results show that two distant pixels are well synchronized during a seizure event.

  13. Sitamaquine Sensitivity in Leishmania Species Is Not Mediated by Drug Accumulation in Acidocalcisomes▿

    PubMed Central

    López-Martín, Carmen; Pérez-Victoria, José María; Carvalho, Luis; Castanys, Santiago; Gamarro, Francisco

    2008-01-01

    Sitamaquine (WR6026), an 8-aminoquinoline derivative, is a new antileishmanial oral drug. As a lipophilic weak base, it rapidly accumulates in acidic compartments, represented mainly by acidocalcisomes. In this work, we show that the antileishmanial action of sitamaquine is unrelated to its level of accumulation in these acidic vesicles. We have observed significant differences in sitamaquine sensitivity and accumulation between Leishmania species and strains, and interestingly, there is no correlation between them. However, there is a relationship between the levels of accumulation of sitamaquine and acidotropic probes, acidocalcisomes size, and polyphosphate levels. The Leishmania major AP3δ-null mutant line, in which acidocalcisomes are devoid of their usual polyphosphate and proton content, is unable to accumulate sitamaquine; however, both the parental strain and the AP3δ-null mutants showed similar sensitivities to sitamaquine. Our findings provide clear evidence that the antileishmanial action of sitamaquine is unrelated to its accumulation in acidocalcisomes. PMID:18794384

  14. [A Case of Drug-Induced Thrombocytopenia Resulting from Sensitivity to Oxaliplatin].

    PubMed

    Masuda, Taiki; Nagai, Kagami; Sanada, Katsuya

    2015-11-01

    A 67-year-old man was diagnosed with pulmonary metastasis from advanced transverse colon cancer. Thus, a local resection was performed. Adjuvant chemotherapy with mFOLFOX6 was started. Sixteen courses were carried out without problems. However, he complained of chills and chest discomfort 2 hours after beginning the 17th course of chemotherapy. Laboratory data showed remarkable thrombocytopenia, and platelet-associated IgG level was high. After administration of steroids and platelet transfusions, the platelet count improved. Therefore, we diagnosed drug-induced thrombocytopenia resulting from sensitivity to oxaliplatin (L-OHP). Since then, sLV5FU2 therapy was started, and the patient received the whole adjuvant chemotherapy without problems. Thrombocytopenia resulting from sensitivity to L-OHP is a relatively rare side effect. We herein report this case with a review of the relevant literature.

  15. Adenovirus replication as an in vitro probe for drug sensitivity in human tumors.

    PubMed

    Parsons, P G; Maynard, K R; Little, J H; McLeod, G R

    1986-04-01

    The feasibility of using adenovirus 5 as an in vitro probe for chemosensitivity in short-term cultures of human tumors was evaluated using human melanoma cell lines and primary cultures of melanoma biopsies. A convenient immunoperoxidase method was developed for quantitating viral replication 2 days after infection. Two different approaches were explored: the host cell reactivation assay (HCR) using drug-treated virus; and the viral capacity assay using drug-treated cells. The HCR assay detected sensitivity to 5-(3-methyl-1-triazeno)imidazole-4-carboxamide (MTIC) in Mer- (methyl excision repair deficient) cell lines as decreased ability of the cells to replicate MTIC-treated virus. This test should be applicable to DNA-damaging agents and repair-deficient tumors. Adenovirus replicated readily in nonproliferating primary cultures of melanoma biopsies; application of the HCR assays to this material identified one Mer- sample of 11 tested. Herpes viruses were not suitable for use in HCR because herpes simplex virus type 1 failed to distinguish Mer- from Mer+ melanoma cells; and nonproductive infection of MTIC-sensitive lymphoid cells with Epstein-Barr virus yielded an MTIC-resistant cell line. The second assay (viral capacity) involved determination of the inhibition of replication of untreated virus in treated cells. This approach correctly predicted sensitivity to hydroxyurea and deoxyadenosine in melanoma cell lines when compared with clonogenic survival assay. Viral capacity was also inhibited by cytosine arabinoside, fluorouracil, vincristine, adriamycin, 6-mercaptopurine and ionising radiation, and may therefore be useful for detecting sensitivity to a wide range of antitumor agents.

  16. Registered report: Systematic identification of genomic markers of drug sensitivity in cancer cells

    PubMed Central

    Vanden Heuvel, John P; Bullenkamp, Jessica

    2016-01-01

    The Reproducibility Project: Cancer Biology seeks to address growing concerns about the reproducibility in scientific research by conducting replications of selected experiments from a number of high-profile papers in the field of cancer biology. The papers, which were published between 2010 and 2012, were selected on the basis of citations and Altmetric scores (Errington et al., 2014). This Registered Report describes the proposed replication plan of key experiments from “Systematic identification of genomic markers of drug sensitivity in cancer cells” by Garnett and colleagues, published in Nature in 2012 (Garnett et al., 2012). The experiments to be replicated are those reported in Figures 4C, 4E, 4F, and Supplemental Figures 16 and 20. Garnett and colleagues performed a high throughput screen assessing the effect of 130 drugs on 639 cancer-derived cell lines in order to identify novel interactions for possible therapeutic approaches. They then tested this approach by exploring in more detail a novel interaction they identified in which Ewing’s sarcoma cell lines showed an increased sensitivity to PARP inhibitors (Figure 4C). Mesenchymal progenitor cells (MPCs) transformed with the signature EWS-FLI1 translocation, the hallmark of Ewing’s sarcoma family tumors, exhibited increased sensitivity to the PARP inhibitor olaparib as compared to MPCs transformed with a different translocation (Figure 4E). Knockdown mediated by siRNA of EWS-FLI1 abrogated this sensitivity to olaparib (Figure 4F). The Reproducibility Project: Cancer Biology is a collaboration between the Center for Open Science and Science Exchange, and the results of the replications will be published by eLife. DOI: http://dx.doi.org/10.7554/eLife.13620.001 PMID:27336789

  17. Codelivery of antitumor drug and gene by a pH-sensitive charge-conversion system.

    PubMed

    Guan, Xiuwen; Li, Yanhui; Jiao, Zixue; Lin, Lin; Chen, Jie; Guo, Zhaopei; Tian, Huayu; Chen, Xuesi

    2015-02-11

    In the present study, a gene and drug codelivery system was developed by electrostatic binding of polyethylenimine-poly(l-lysine)-poly(l-glutamic acid) (PELG), polyethylenimine (PEI), cis-aconityl-doxorubicin (CAD), and DNA. Zeta potential and drug release analysis confirmed the pH-responsive charge conversion and acid-sensitive drug release functional properties of the PELG/PEI/(DNA+CAD) system. Gel retardation assay and transfection experiment showed the codelivery system had effective DNA binding ability and good transfection efficiency on HepG2 cells. The therapeutic gene p53 was further employed to study its combinational effects with CAD. Cytotoxicity assay showed the half inhibitory concentration (IC50) of the PELG/PEI/(p53+CAD) codelivery system was lower than that of the gene or the drug delivery system. Confocal laser scanning microscopy (CLSM) showed that the drug and gene could be delivered into the cells simultaneously. A significant increase of p53 gene expression was achieved after HepG2 cells treated by PELG/PEI/(p53+CAD) codelivery system. The apoptosis experiment indicated clearly that the codelivery system could lead an effective apoptosis on tumor cells, which was beneficial for the treatment of cancer. The biodistribution and tumor accumulation of the codelivery system was explored via in vivo imaging in subcutaneous xenograft and in situ tumor models. The tumor and some major organs were excised and imaged, and the results showed that the codelivery system can accumulate efficiently in tumor for both tumor models. It can be suggested from the above results that the PELG/PEI/(DNA+CAD) codelivery system will have great potential applications in cancer therapy.

  18. Combinatorial high-throughput experimental and bioinformatic approach identifies molecular pathways linked with the sensitivity to anticancer target drugs

    PubMed Central

    Venkova, Larisa; Aliper, Alexander; Suntsova, Maria; Kholodenko, Roman; Shepelin, Denis; Borisov, Nicolas; Malakhova, Galina; Vasilov, Raif; Roumiantsev, Sergey; Zhavoronkov, Alex; Buzdin, Anton

    2015-01-01

    Effective choice of anticancer drugs is important problem of modern medicine. We developed a method termed OncoFinder for the analysis of new type of biomarkers reflecting activation of intracellular signaling and metabolic molecular pathways. These biomarkers may be linked with the sensitivity to anticancer drugs. In this study, we compared the experimental data obtained in our laboratory and in the Genomics of Drug Sensitivity in Cancer (GDS) project for testing response to anticancer drugs and transcriptomes of various human cell lines. The microarray-based profiling of transcriptomes was performed for the cell lines before the addition of drugs to the medium, and experimental growth inhibition curves were built for each drug, featuring characteristic IC50 values. We assayed here four target drugs - Pazopanib, Sorafenib, Sunitinib and Temsirolimus, and 238 different cell lines, of which 11 were profiled in our laboratory and 227 - in GDS project. Using the OncoFinder-processed transcriptomic data on ∼600 molecular pathways, we identified pathways showing significant correlation between pathway activation strength (PAS) and IC50 values for these drugs. Correlations reflect relationships between response to drug and pathway activation features. We intersected the results and found molecular pathways significantly correlated in both our assay and GDS project. For most of these pathways, we generated molecular models of their interaction with known molecular target(s) of the respective drugs. For the first time, our study uncovered mechanisms underlying cancer cell response to drugs at the high-throughput molecular interactomic level. PMID:26317900

  19. Magnetic and pH-sensitive nanoparticles for antitumor drug delivery.

    PubMed

    Yu, Shufang; Wu, Guolin; Gu, Xin; Wang, Jingjing; Wang, Yinong; Gao, Hui; Ma, Jianbiao

    2013-03-01

    A dually responsive nanocarrier with multilayer core-shell architecture was prepared based on Fe(3)O(4)@SiO(2) nanoparticles coated with mPEG-poly(l-Asparagine). Imidazole groups (pK(a)∼6.0) were tethered to the side chains of poly(l-Asparagine) segments by aminolysis. These nanoparticles were expected to be sensitive to both magnetic field and pH environment. The obtained materials were characterized with FTIR, dynamic light scattering, ζ-potential, TEM, TGA and hysteresis loop analysis. It was found that this Fe(3)O(4)@SiO(2)-polymer complex can form nano-scale core-shell-corona trilayer particles (∼250 nm) in aqueous solution. The Fe(3)O(4)@SiO(2), poly(L-Asparagine) and mPEG segments serve as a super-paramagnetic core, a pH-sensitive shell, and a hydrophilic corona, respectively. An antitumor agent, doxorubicin (DOX), was successfully loaded into the nanocarrier via combined actions of hydrophobic interaction and hydrogen bonding. The drug release profiles displayed a pH-dependent behavior. DOX release rate increased significantly as the ambient pH dropped from the physiological pH (7.4) to acidic (5.5). This is most likely due to protonation and a change in hydrophilicity of the imidazole groups in the poly(l-Asparagine) segments. This new approach may serve as a promising platform to formulate magnetic targeted drug delivery systems.

  20. Sensitive derivatization methods for the determination of genotoxic impurities in drug substances using hyphenated techniques.

    PubMed

    Raman, Nanduri V V S S; Prasad, Adapa V S S; Reddy, Kura Ratnakar

    2014-02-01

    Six sensitive derivatization methods for the determination of genotoxic impurities in selected drug substances were developed using hyphenated techniques. Some of the raw materials, reagents and reaction intermediates of the selected drug substances were identified as genotoxic impurities through DEREK software for windows. The genotoxic impurities which are amenable for derivatization were selected as substrates. Derivatizing agents were selected based on the functional groups of the genotoxic impurities. The chemistry involved in the derivatization was explained with suitable mechanisms. An appropriate hyphenated technique viz. LC-MS and GC-MS was opted based on the sensitivity and aromaticity of the derivatized genotoxic impurities. All the methods were validated as per International Conference on Harmonization guidelines. Correlation coefficient values were found about 0.99. The obtained % R.S.D values from replicate injections in the range of 2.3-4.8 and % recoveries of the added impurities in the range of 83.7-101.7 ensured the precision and accuracy, respectively.

  1. The pH-sensitive polyampholyte nanogels: inclusion of carbon nanotubes for improved drug loading.

    PubMed

    Sankar, Rajavelu Murali; Seeni Meera, Kamal Mohamed; Samanta, Debasis; Jithendra, Panneerselvam; Mandal, Asit Baran; Jaisankar, Sellamuthu N

    2013-12-01

    We report a simple and facile method to prepare a novel pH sensitive polyampholyte nanogel by copolymerizing vinylimidazole (VIM) with acrylic acid (AA) using functionalized single-walled carbon nanotubes (f-SWCNTs) (as reinforcing material) and cyanuric chloride via an intermolecular quaternization reaction. The polyampholyte nanogels have been characterized by various microscopic and spectroscopic methods. These studies reveal that incorporation of nanotubes in cross-linked copolymer of poly(vinylimidazole-co-acrylic acid) (PVI-co-AA) form polyampholyte nanogel with enhanced physical properties. The thermal experiments show that the introduction of f-SWCNTs into PVI-co-AA has significant impact on the thermal stability of nanogels. The rheological study showed that the nanogel is more viscoelastic than native gel. MTT assay indicates that the prepared polyampholyte gels possess biocompatibility and cell viability. The nanogel is also useful material to load water-soluble drug such as promethazine hydrochloride. The releasing profile of the drug from the nanogel clearly shows the pH-sensitive property of the material.

  2. Merging traditional Chinese medicine with modern drug discovery technologies to find novel drugs and functional foods.

    PubMed

    Graziose, Rocky; Lila, Mary Ann; Raskin, Ilya

    2010-03-01

    Traditional Chinese Medicines (TCM) are rapidly gaining attention in the West as sources of new drugs, dietary supplements and functional foods. However, lack of consistent manufacturing practices and quality standards, fear of adulteration, and perceived deficiencies in scientific validation of efficacy and safety impede worldwide acceptance of TCM. In addition, Western pharmaceutical industries and regulatory agencies are partial toward single ingredient drugs based on synthetic molecules, and skeptical of natural product mixtures. This review concentrates on three examples of TCM-derived pharmaceuticals and functional foods that have, despite these usual obstacles, risen to wide acceptance in the West based on their remarkable performance in recent scientific investigations. They are: Sweet wormwood (Artemisia annua), the source of artemisinin, which is the currently preferred single compound anti-malarial drug widely used in combination therapies and recently approved by US FDA; Thunder god vine (Tripterygium wilfordii) which is being developed as a botanical drug for rheumatoid arthritis; and green tea (Camellia sinensis) which is used as a functional beverage and a component of dietary supplements.

  3. Merging Traditional Chinese Medicine with Modern Drug Discovery Technologies to Find Novel Drugs and Functional Foods

    PubMed Central

    Graziose, Rocky; Lila, Mary Ann; Raskin, Ilya

    2011-01-01

    Traditional Chinese Medicines (TCM) are rapidly gaining attention in the West as sources of new drugs, dietary supplements and functional foods. However, lack of consistent manufacturing practices and quality standards, fear of adulteration, and perceived deficiencies in scientific validation of efficacy and safety impede worldwide acceptance of TCM. In addition, Western pharmaceutical industries and regulatory agencies are partial toward single ingredient drugs based on synthetic molecules, and skeptical of natural product mixtures. This review concentrates on three examples of TCM-derived pharmaceuticals and functional foods that have, despite these usual obstacles, risen to wide acceptance in the West based on their remarkable performance in recent scientific investigations. They are: Sweet wormwood (Artemisia annua), the source of artemisinin, which is the currently preferred single compound anti-malarial drug widely used in combination therapies and recently approved by US FDA; Thunder god vine (Tripterygium wilfordii) which is being developed as a botanical drug for rheumatoid arthritis; and green tea (Camellia sinensis) which is used as a functional beverage and a component of dietary supplements. PMID:20156139

  4. Sensitivity of drug-resistant mutants of hepatitis B virus to poly-IC.

    PubMed

    Zhou, Q; Chen, E; Chen, L; Nong, Y; Cheng, X; He, M; Tang, H

    2014-01-01

    The long-term benefits of antiviral treatment are limited by the resistance of hepatitis B virus (HBV). However, the effect of interferon (IFN)α treatment on drug-resistant HBVs is so far unknown. We, therefore, investigated the effects of IFN-α inducer poly-IC on the replication of HBV mutants resistant to drugs such as lamivudine (LAM), adefovir dipivoxil (ADV) and entecavir (ETV) in mice. HBV DNA and HBV DNA intermediate (RI) were employed as markers of the virus replication and 2',5'-oligoadenylate synthase (OAS) mRNA as a marker of IFN-α/β induction. Poly-IC inhibited wtHBV replication and increased levels of OAS mRNA. Compared to the wt virus, the capacity of virus replication was reduced in most LAMr and ETVr mutants except those with mutations rtM(204V+L180M+V173L), and was similary in the ADVr mutants except rt(A121V+N236T). The virus replication was reduced after poly-IC treatment with LAMr and ADVr mutants similary to the wt virus. In contrast, ETVr mutants were resistant to the poly-IC treatment. In conclusion, the capacity of HBV replication and the sensitivity to IFN therapy are influenced by drug-resistant mutations. The IFN therapy may effectively inhibit HBV replication in particular in patients with LAMr or ADVr mutations but not in patients with ETVr mutations.

  5. Re-sensitizing drug-resistant bacteria to antibiotics by designing Antisense Therapeutics

    NASA Astrophysics Data System (ADS)

    Courtney, Colleen; Chatterjee, Anushree

    2014-03-01

    ``Super-bugs'' or ``multi-drug resistant organisms'' are a serious international health problem, with devastating consequences to patient health care. The Center for Disease Control has identified antibiotic resistance as one of the world's most pressing public health problems as a significant fraction of bacterial infections contracted are drug resistant. Typically, antibiotic resistance is encoded by ``resistance-genes'' which express proteins that carryout the resistance causing functions inside the bacterium. We present a RNA based therapeutic strategy for designing antimicrobials capable of re-sensitizing resistant bacteria to antibiotics by targeting labile regions of messenger RNAs encoding for resistance-causing proteins. We perform in silico RNA secondary structure modeling to identify labile target regions in an mRNA of interest. A synthetic biology approach is then used to administer antisense nucleic acids to our model system of ampicillin resistant Escherichia coli. Our results show a prolonged lag phase and decrease in viability of drug-resistant E. colitreated with antisense molecules. The antisense strategy can be applied to alter expression of other genes in antibiotic resistance pathways or other pathways of interest.

  6. Microenvironment-derived HGF overcomes genetically determined sensitivity to anti-MET drugs.

    PubMed

    Pennacchietti, Selma; Cazzanti, Manuela; Bertotti, Andrea; Rideout, William M; Han, May; Gyuris, Jeno; Perera, Timothy; Comoglio, Paolo M; Trusolino, Livio; Michieli, Paolo

    2014-11-15

    Cell-based drug screenings indicate that tumors displaying c-MET gene amplification are "addicted" to MET signaling and therefore are very sensitive to MET-targeted agents. However, these screenings were conducted in the absence of the MET ligand, hepatocyte growth factor (HGF), which is abundant in the tumor microenvironment. Sensitivity of six MET-addicted human tumor cells to three MET kinase inhibitors (JNJ-38877605, PHA-665752, crizotinib) and one antagonistic anti-MET antibody (DN30 Fab) was analyzed in the absence or presence of HGF, in a stroma-tumor coculture system, and by combining anti-MET drugs with an HGF neutralizing antibody (ficlatuzumab) in human HGF knock-in mice bearing c-MET-amplified tumors. In all models examined, HGF promoted resistance to MET-targeted agents, affecting both their potency and efficacy. HGF-induced resistance was due to restoration of physiologic GAB1-mediated PI3K activation that compensated for loss of aberrant HER3-dependent PI3K signaling. Ficlatuzumab restored sensitivity to MET-targeted agents in coculture systems and overcame resistance to JNJ-38877605, crizotinib, and DN30 Fab in human HGF knock-in mice. These data suggest that c-MET-amplified tumor cells-which normally exhibit ligand-independent, constitutive MET activation-become dependent on HGF for survival upon pharmacologic MET inhibition. Because HGF is frequently overexpressed in human cancer, this mechanism may represent a major cause of resistance to anti-MET therapies. The ability of ficlatuzumab to overcome HGF-mediated resistance generates proof of principle that vertical inhibition of both a tyrosine kinase receptor and its ligand can be therapeutically beneficial and opens new perspectives for the treatment of MET-dependent tumors.

  7. PPO/PEO modified hollow fiber membranes improved sensitivity of 3D cultured hepatocytes to drug toxicity via suppressing drug adsorption on membranes.

    PubMed

    Shen, Chong; Meng, Qin; He, Wenjuan; Wang, Qichen; Zhang, Guoliang

    2014-11-01

    The three dimensional (3D) cell culture in polymer-based micro system has become a useful tool for in vitro drug discovery. Among those polymers, polysulfone hollow fiber membrane (PSf HFM) is commonly used to create a microenvironment for cells. However, the target drug may adsorb on the polymeric surface, and this elicits negative impacts on cell exposure due to the reduced effective drug concentration in culture medium. In order to reduce the drug adsorption, PSf membrane were modified with hydrophilic Pluronic (PEO-b-PPO-b-PEO) copolymers, L121, P123 and F127 (PEO contents increase from 10%, 30% to 70%), by physical adsorption. As a result, the hydrophilicity of HFMs increased at an order of PSfF127>P123>L121 HFMs. The three modified membrane all showed significant resistance to adsorption of acid/neutral drugs. More importantly, the adsorption of base drugs were largely reduced to an average value of 11% on the L121 HFM. The improved resistance to drug adsorption could be attributed to the synergy of hydrophobic/neutrally charged PPO and hydrophilic PEO. The L121 HFM was further assessed by evaluating the drug hepatotoxicity in 3D culture of hepatocytes. The base drugs, clozapine and doxorubicin, showed more sensitive hepatotoxicity on hepatocytes in L121 HFM than in PSf HFM, while the acid drug, salicylic acid, showed the similar hepatotoxicity to hepatocytes in both HFMs. Our finding suggests that PSf HFM modified by PEO-b-PPO-b-PEO copolymers can efficiently resist the drug adsorption onto polymer membrane, and consequently improve the accuracy and sensitivity of in vitro hepatotoxic drug screening.

  8. Peripheral insulin-sensitizer drug metformin ameliorates neuronal insulin resistance and Alzheimer's-like changes.

    PubMed

    Gupta, Amit; Bisht, Bharti; Dey, Chinmoy Sankar

    2011-05-01

    Alzheimer's disease (AD) is the most common neurodegenerative disease worldwide. Pharmacological treatments presently available can slow down the progression of symptoms but can not cure the disease. Currently there is widening recognition that AD is closely associated with impaired insulin signaling and glucose metabolism in brain, suggesting it to be a brain-specific form of diabetes and so also termed as "type 3 diabetes". Hence investigating the role of pharmacological agents that could ameliorate neuronal insulin resistance merit attention in AD therapeutics, however the therapeutics for pathophysiological condition like neuronal insulin resistance itself is largely unknown. In the present study we have determined the effect of metformin on neuronal insulin resistance and AD-associated characteristics in an in vitro model of "type 3 diabetes" by differentiating neuronal cell line Neuro-2a under prolonged presence of insulin. We observed that prolonged hyperinsulinemic conditions in addition to generating insulin resistance also led to development of hallmark AD-associated neuropathological changes. Treatment with metformin sensitized the impaired insulin actions and also prevented appearance of molecular and pathological characteristics observed in AD. The results thus demonstrate possible therapeutic efficacy of peripheral insulin-sensitizer drug metformin in AD by its ability to sensitize neuronal insulin resistance. These findings also provide direct evidences linking hyperinsulinemia and AD and suggest a unique opportunity for prevention and treatment of "type 3 diabetes".

  9. Validation of a sensitive ion chromatography method for determination of monoethylsulfate in Indinavir sulfate drug substance.

    PubMed

    Prasanna, S John; Sharma, Hemant Kumar; Mukkanti, K; Sivakumaran, M; Pavan Kumar, K S R; Kumar, V Jagadeesh

    2009-12-05

    The present study relates to the optimization of an ion chromatography method to determine the content of monoethylsulfate at very low levels in Indinavir sulfate drug substance, and subsequent validation of the method to prove its suitability, reliability and sensitivity. Monoethylsulfate is a potential impurity of Indinavir sulfate, and may forms during the preparation as well as during storage. The ion chromatography method was developed in such a way that to enhance the detection level by introducing suppressor, and minimizing acquisition time by using suitable buffer of 3.2 mmole of sodium carbonate and 1 mmole of sodium hydrogen carbonate in water as eluent. The retention time of monoethylsulfate was about 9.5 min and the total acquisition time was 25 min. The optimized method was validated to prove its performance characteristics by demonstrating selectivity, sensitivity (limit of detection and quantification), linearity, precision and accuracy. The established limit of detection and quantification of monoethylsulfate in Indinavir sulfate by this method was found to be 24 ng/ml and 74 ng/ml respectively, and the overall percent accuracy (recovery) of samples evaluated at different concentration levels was found to be 97.1, indicating the sensitivity and accuracy of this optimized ion chromatography method.

  10. Simple PCR Assays Improve the Sensitivity of HIV-1 Subtype B Drug Resistance Testing and Allow Linking of Resistance Mutations

    PubMed Central

    Johnson, Jeffrey A.; Li, Jin-Fen; Wei, Xierong; Lipscomb, Jonathan; Bennett, Diane; Brant, Ashley; Cong, Mian-er; Spira, Thomas; Shafer, Robert W.; Heneine, Walid

    2007-01-01

    Background The success of antiretroviral therapy is known to be compromised by drug-resistant HIV-1 at frequencies detectable by conventional bulk sequencing. Currently, there is a need to assess the clinical consequences of low-frequency drug resistant variants occurring below the detection limit of conventional genotyping. Sensitive detection of drug-resistant subpopulations, however, requires simple and practical methods for routine testing. Methodology We developed highly-sensitive and simple real-time PCR assays for nine key drug resistance mutations and show that these tests overcome substantial sequence heterogeneity in HIV-1 clinical specimens. We specifically used early wildtype virus samples from the pre-antiretroviral drug era to measure background reactivity and were able to define highly-specific screening cut-offs that are up to 67-fold more sensitive than conventional genotyping. We also demonstrate that sequencing the mutation-specific PCR products provided a direct and novel strategy to further detect and link associated resistance mutations, allowing easy identification of multi-drug-resistant variants. Resistance mutation associations revealed in mutation-specific amplicon sequences were verified by clonal sequencing. Significance Combined, sensitive real-time PCR testing and mutation-specific amplicon sequencing provides a powerful and simple approach that allows for improved detection and evaluation of HIV-1 drug resistance mutations. PMID:17653265

  11. A sensitive multidimensional method for the detection, characterization, and quantification of trace free drug species in antibody-drug conjugate samples using mass spectral detection

    PubMed Central

    Birdsall, Robert E.; McCarthy, Sean M.; Janin-Bussat, Marie Claire; Perez, Michel; Haeuw, Jean-François; Chen, Weibin; Beck, Alain

    2016-01-01

    abstract Conjugation processes and stability studies associated with the production and shelf life of antibody-drug conjugates (ADCs) can result in free (non-conjugated) drug species. These free drug species can increase the risk to patients and reduce the efficacy of the ADC. Despite stringent purification steps, trace levels of free drug species may be present in formulated ADCs, reducing the therapeutic window. The reduction of sample preparation steps through the incorporation of multidimensional techniques has afforded analysts more efficient methods to assess trace drug species. Multidimensional methods coupling size-exclusion and reversed phase liquid chromatography with ultra-violet detection (SEC-RPLC/UV) have been reported, but offer limited sensitivity and can limit method optimization. The current study addresses these challenges with a multidimensional method that is specific, sensitive, and enables method control in both dimensions via coupling of an on-line solid phase extraction column to RPLC with mass spectral detection (SPE-RPLC/MS). The proposed method was evaluated using an antibody-fluorophore conjugate (AFC) as an ADC surrogate to brentuximab vedotin and its associated parent maleimide-val-cit-DSEA payload and the derived N-acetylcysteine adduct formed during the conjugation process. Assay sensitivity was found to be 2 orders more sensitive using MS detection in comparison to UV-based detection with a nominal limit of quantitation of 0.30 ng/mL (1.5 pg on-column). Free-drug species were present in an unadulterated ADC surrogate sample at concentrations below 7 ng/mL, levels not detectable by UV alone. The proposed SPE-RPLC/MS method provides a high degree of specificity and sensitivity in the assessment of trace free drug species and offers improved control over each dimension, enabling straightforward integration into existing or novel workflows. PMID:26651262

  12. Assessment of substance abuse liability in rodents: self-administration, drug discrimination, and locomotor sensitization.

    PubMed

    Paterson, Neil E

    2012-09-01

    Assessing abuse liability is a crucial step in the development of a novel chemical entity (NCE) with central nervous system (CNS) activity or with chemical or pharmacological properties in common with known abused substances. Rodent assessment of abuse liability is highly attractive due to its relatively low cost and high predictive validity. Described in this unit are three rodent assays commonly used to provide data on the potential for abuse liability based on the acute effects of NCEs: specifically, self-administration, drug discrimination, and locomotor sensitization. As these assays provide insight into the potential abuse liability of NCEs as well as in vivo pharmacological mechanism(s) of action, they should form a key part of the development process for novel therapeutics aimed at treating CNS disorders.

  13. Activating mutations and senescence secretome: new insights into HER2 activation, drug sensitivity and metastatic progression.

    PubMed

    Acharyya, Swarnali

    2013-04-23

    HER2 amplification and overexpression is observed in approximately 20% of breast cancers and is strongly associated with poor prognosis and therapeutic responsiveness to HER2 targeted agents. A recent study by Bose and colleagues suggests that another subset of breast cancer patients without HER2 amplification but with activating HER2 mutation might also benefit from existing HER2-targeted agents and the authors functionally characterize these somatic mutations in experimental models. In a second study on HER2-driven breast cancer, Angelini and colleagues investigate how the constitutively active, truncated carboxy-terminal fragment of HER2, p95HER2, promotes metastatic progression through non-cellautonomous secretion of factors from senescent cells. These new findings advance our understanding of HER2 biology in the context of HER2 activation as well as offer new insights into our understanding of drug sensitivity and metastatic progression.

  14. Candida albicans and Candida tropicalis in oral candidosis: quantitative analysis, exoenzyme activity, and antifungal drug sensitivity.

    PubMed

    da Costa, Karen Regina Carim; Ferreira, Joseane Cristina; Komesu, Marilena Chinali; Candido, Regina Celia

    2009-02-01

    Candida albicans and C. tropicalis obtained from whole saliva of patients presenting signs of oral candidosis were assayed for quantification of colony forming units, exoenzyme activity (phospholipase and proteinase) and antifungal drug sensitivity (amphotericin B, fluconazole and itraconazole) by the reference method of the Clinical and Laboratory Standards Institute. The number of colony forming units per milliliter varied according to the Candida species involved and whether a single or mixed infection was present. Proteinase activity was observed in both C. albicans and C. tropicalis, but phospholipase activity was noted only in C. albicans. In vitro resistance to antifungals was verified in both species, but C. tropicalis appears to be more resistant to the tested antifungals than C. albicans.

  15. Flow perfusion effects on three-dimensional culture and drug sensitivity of Ewing sarcoma

    PubMed Central

    Santoro, Marco; Lamhamedi-Cherradi, Salah-Eddine; Menegaz, Brian A.; Ludwig, Joseph A.; Mikos, Antonios G.

    2015-01-01

    Three-dimensional tumor models accurately describe different aspects of the tumor microenvironment and are readily available for mechanistic studies of tumor biology and for drug screening. Nevertheless, these systems often overlook biomechanical stimulation, another fundamental driver of tumor progression. To address this issue, we cultured Ewing sarcoma (ES) cells on electrospun poly(ε-caprolactone) 3D scaffolds within a flow perfusion bioreactor. Flow-derived shear stress provided a physiologically relevant mechanical stimulation that significantly promoted insulin-like growth factor-1 (IGF1) production and elicited a superadditive release in the presence of exogenous IGF1. This finding is particularly relevant, given the central role of the IGF1/IGF-1 receptor (IGF-1R) pathway in ES tumorigenesis and as a promising clinical target. Additionally, flow perfusion enhanced in a rate-dependent manner the sensitivity of ES cells to IGF-1R inhibitor dalotuzumab (MK-0646) and showed shear stress-dependent resistance to the IGF-1R blockade. This study demonstrates shear stress-dependent ES cell sensitivity to dalotuzumab, highlighting the importance of biomechanical stimulation on ES-acquired drug resistance to IGF-1R inhibition. Furthermore, flow perfusion increased nutrient supply throughout the scaffold, enriching ES culture over static conditions. Our use of a tissue-engineered model, rather than human tumors or xenografts, enabled precise control of the forces experienced by ES cells, and therefore provided at least one explanation for the remarkable antineoplastic effects observed by some ES tumor patients from IGF-1R targeted therapies, in contrast to the lackluster effect observed in cells grown in conventional monolayer culture. PMID:26240353

  16. SynLethDB: synthetic lethality database toward discovery of selective and sensitive anticancer drug targets.

    PubMed

    Guo, Jing; Liu, Hui; Zheng, Jie

    2016-01-04

    Synthetic lethality (SL) is a type of genetic interaction between two genes such that simultaneous perturbations of the two genes result in cell death or a dramatic decrease of cell viability, while a perturbation of either gene alone is not lethal. SL reflects the biologically endogenous difference between cancer cells and normal cells, and thus the inhibition of SL partners of genes with cancer-specific mutations could selectively kill cancer cells but spare normal cells. Therefore, SL is emerging as a promising anticancer strategy that could potentially overcome the drawbacks of traditional chemotherapies by reducing severe side effects. Researchers have developed experimental technologies and computational prediction methods to identify SL gene pairs on human and a few model species. However, there has not been a comprehensive database dedicated to collecting SL pairs and related knowledge. In this paper, we propose a comprehensive database, SynLethDB (http://histone.sce.ntu.edu.sg/SynLethDB/), which contains SL pairs collected from biochemical assays, other related databases, computational predictions and text mining results on human and four model species, i.e. mouse, fruit fly, worm and yeast. For each SL pair, a confidence score was calculated by integrating individual scores derived from different evidence sources. We also developed a statistical analysis module to estimate the druggability and sensitivity of cancer cells upon drug treatments targeting human SL partners, based on large-scale genomic data, gene expression profiles and drug sensitivity profiles on more than 1000 cancer cell lines. To help users access and mine the wealth of the data, we developed other practical functionalities, such as search and filtering, orthology search, gene set enrichment analysis. Furthermore, a user-friendly web interface has been implemented to facilitate data analysis and interpretation. With the integrated data sets and analytics functionalities, SynLethDB would

  17. Highly Sensitive and Validated Spectrophotometric Technique for the Assay of Some Antidepressant Drugs

    NASA Astrophysics Data System (ADS)

    Deepakumari, H. N.; Prashanth, M. K.; Kumar, B. C. Vasantha; Revanasiddappa, H. D.

    2015-01-01

    The present paper describes a simple, rapid, reproducible, and highly sensitive spectrophotometric method for the determination of the tricyclic antidepressant drugs: amitriptyline hydrochloride (AMT), imipramine hydrochloride (IMH), clomipramine hydrochloride (CPH) and desipramine hydrochloride (DPH) in pure and in pharmaceutical preparations. The method is based on the bromination of the above drugs with known excess of bromine. The unreacted bromine is determined based on its ability to bleach the dye methyl red quantitatively at 520 nm. Regression analysis of Beer-Lambert plots showed a good correlation in the concentration range 0.0-2.5, 0-1.4, 0-1.4, and 0-1.0 μg/ml for AMT, IMH, CPH, and DPH, respectively. The molar absorptivity values were found to be 0.65 × 105, 1.41 × 105, 1.93 × 105, and 2.96 × 105l/mol/cm, with the corresponding Sandell's sensitivity values were 0.0048, 0.0022, 0.0018, and 0.0010 μg/cm2 for AMT, IMH, CPH, and DPH, respectively. The limits of detection (LOD) and quantification (LOQ) are also reported for the developed method. Intra- and inter-day accuracy and precision was established according to the current ICH guidelines. Application of the procedure to the analysis of various pharmaceutical preparations gave reproducible and accurate results. Further, the validity of the proposed method was confirmed by applying the standard addition technique, and the results obtained are in good agreement with those obtained by the official method.

  18. Competition between novelty and cocaine conditioned reward is sensitive to drug dose and retention interval

    PubMed Central

    Reichel, Carmela M.; Bevins, Rick A.

    2010-01-01

    The following manuscript is the final accepted manuscript. It has not been subjected to the final copyediting, fact-checking, and proofreading required for formal publication. It is not the definitive, publisher-authenticated version. The American Psychological Association and its Council of Editors disclaim any responsibility or liabilities for errors or omissions of this manuscript version, any version derived from this manuscript by NIH, or other third parties. The published version is available at www.apa.org/pubs/journals/bne The conditioned rewarding effects of novelty compete with those of cocaine for control over choice behavior using a place-conditioning task. The purpose of the present study was to use multiple doses of cocaine to determine the extent of this competition and to determine whether novelty's impact on cocaine reward was maintained over an abstinence period. In Experiment 1, rats were conditioned with cocaine (7.5, 20, or 30 mg/kg, IP) to prefer one side of an unbiased place conditioning apparatus relative to the other. In a subsequent phase, all rats received alternating daily confinements to the previously cocaine-paired and unpaired sides of the apparatus. During this phase, half the rats had access to a novel object on their initially unpaired side; the remaining rats did not receive objects. The ability of novelty to compete with cocaine in a drug-free and cocaine-challenge test was sensitive to cocaine dose. In Experiment 2, a place preference was established with 10 mg/kg cocaine and testing occurred after 1, 14, or 28 day retention intervals. Findings indicate that choice behaviors mediated by cocaine conditioning are reduced with the passing of time. Taken together, competition between cocaine and novelty conditioned rewards are sensitive to drug dose and retention interval. PMID:20141289

  19. Antiarrhythmic drugs, clofilium and cibenzoline are potent inhibitors of glibenclamide-sensitive K+ currents in Xenopus oocytes.

    PubMed Central

    Sakuta, H.; Okamoto, K.; Watanabe, Y.

    1993-01-01

    1. The novel K+ channel opener, Y-26763 induced outward K+ currents in voltage-clamped follicle-enclosed Xenopus oocytes in a concentration-dependent manner with an EC50 value of 58 microM. 2. The Y-26763-induced K+ current was completely and reversibly blocked by glibenclamide (an ATP-sensitive K+ channel blocker) in a concentration-dependent manner (IC50 140 nM). Effects of several antiarrhythmic drugs on Y-26763-induced glibenclamide-sensitive K+ currents were investigated. 3. (+/-)-Cibenzoline, RS-2135, pirmenol, lorcainide and KW-3407 (class I antiarrhythmic drugs, Na+ channel blockers) suppressed Y-26763 responses in a concentration-dependent manner with IC50 values (in microM) of 6.6, 54, 68, 71 and 370, respectively. 4. Clofilium, E-4031, MS-551 and bretylium (class III antiarrhythmic drugs which increase the action potential duration) also suppressed Y-26763 responses concentration-dependently, IC50 values (in microM) were 3.3, 660, 980 and > or = 2000, respectively. N-acetylprocainamide (class III antiarrhythmic drug) scarcely suppressed Y-26763 responses. 5. The glibenclamide-sensitive K+ currents elicited by KRN2391 were also suppressed by all these antiarrhythmic drugs. 6. The antiarrhythmic drugs, clofilium and (+/-)-cibenzoline block glibenclamide-sensitive K+ channels in Xenopus oocytes at concentrations comparable to their therapeutic plasma levels. PMID:8358576

  20. Computational cell fate modelling for discovery of rewiring in apoptotic network for enhanced cancer drug sensitivity.

    PubMed

    Mishra, Shital K; Bhowmick, Sourav S; Chua, Huey; Zhang, Fan; Zheng, Jie

    2015-01-01

    The ongoing cancer research has shown that malignant tumour cells have highly disrupted signalling transduction pathways. In cancer cells, signalling pathways are altered to satisfy the demands of continuous proliferation and survival. The changes in signalling pathways supporting uncontrolled cell growth, termed as rewiring, can lead to dysregulation of cell fates e.g. apoptosis. Hence comparative analysis of normal and oncogenic signal transduction pathways may provide insights into mechanisms of cancer drug-resistance and facilitate the discovery of novel and effective anti-cancer therapies. Here we propose a hybrid modelling approach based on ordinary differential equation (ODE) and machine learning to map network rewiring in the apoptotic pathways that may be responsible for the increase of drug sensitivity of tumour cells in triple-negative breast cancer. Our method employs Genetic Algorithm to search for the most likely network topologies by iteratively generating simulated protein phosphorylation data using ODEs and the rewired network and then fitting the simulated data with real data of cancer signalling and cell fate. Most of our predictions are consistent with experimental evidence from literature. Combining the strengths of knowledge-driven and data-driven approaches, our hybrid model can help uncover molecular mechanisms of cancer cell fate at systems level.

  1. A simple and sensitive spectrofluorimetric method for analysis of some nitrofuran drugs in pharmaceutical preparations.

    PubMed

    Belal, Tarek Saied

    2008-09-01

    A simple, rapid, selective and sensitive spectrofluorimetric method was described for the analysis of three nitrofuran drugs, namely, nifuroxazide (NX), nitrofurantoin (NT) and nitrofurazone (NZ). The method involved the alkaline hydrolysis of the studied drugs by warming with 0.1 M sodium hydroxide solution then dilution with distilled water for NX or 2-propanol for NT and NZ. The formed fluorophores were measured at 465 nm (lambda (Ex) 265 nm), 458 nm (lambda (Ex) 245 nm) and 445 nm (lambda (Ex) 245 nm) for NX, NT and NZ, respectively. The reaction pathway was discussed and the structures of the fluorescent products were proposed. The different experimental parameters were studied and optimized. Regression analysis showed good correlation between fluorescence intensity and concentration over the ranges 0.08-1.00, 0.02-0.24 and 0.004-0.050 microg ml(-1) for NX, NT and NZ, respectively. The limits of detection of the method were 8.0, 1.9 and 0.3 ng ml(-1) for NX, NT and NZ, respectively. The proposed method was validated in terms of accuracy, precision and specificity, and it was successfully applied for the assay of the three nitrofurans in their different dosage forms. No interference was observed from common pharmaceutical adjuvants. The results were favorably compared with those obtained by reference spectrophotometric methods.

  2. Development of pH-sensitive pectinate/alginate microspheres for colon drug delivery.

    PubMed

    Hsu, Fu-Yin; Yu, Ding-Syuan; Huang, Chun-Chiang

    2013-02-01

    The purposes of this study were to develop and evaluate calcium pectinate/alginate microspheres (PAMs) and to exploit their pH-sensitive properties for colon-targeted delivery of encapsulated cisplatin. PAMs were prepared using an electrospraying method. The PAMs, as cores, were then coated with Eudragit S100 using a polyelectrolyte multilayer coating technique in aqueous solution. The morphology of the microspheres was observed under scanning electron microscopy. In vitro drug release studies were performed in simulated gastrointestinal fluid, and the results indicated that approximately 5 % of the cisplatin was released from the Eudragit S100-coated PAMs, and 51 % of the cisplatin was released from the uncoated PAMs at 1 h. The release of cisplatin from the Eudragit S100-coated PAMs was more sustained in simulated gastric fluid than in simulated intestinal fluid due to the increased solubility of the coating polymer in media with pH >7.0. Drug release from the Eudragit S100-coated PAMs was best described by the Higuchi's square root model. From these results, it was concluded that Eudragit S100-coated PAMs are a potential carrier for delivery of cisplatin to the colon.

  3. Computational cell fate modelling for discovery of rewiring in apoptotic network for enhanced cancer drug sensitivity

    PubMed Central

    2015-01-01

    The ongoing cancer research has shown that malignant tumour cells have highly disrupted signalling transduction pathways. In cancer cells, signalling pathways are altered to satisfy the demands of continuous proliferation and survival. The changes in signalling pathways supporting uncontrolled cell growth, termed as rewiring, can lead to dysregulation of cell fates e.g. apoptosis. Hence comparative analysis of normal and oncogenic signal transduction pathways may provide insights into mechanisms of cancer drug-resistance and facilitate the discovery of novel and effective anti-cancer therapies. Here we propose a hybrid modelling approach based on ordinary differential equation (ODE) and machine learning to map network rewiring in the apoptotic pathways that may be responsible for the increase of drug sensitivity of tumour cells in triple-negative breast cancer. Our method employs Genetic Algorithm to search for the most likely network topologies by iteratively generating simulated protein phosphorylation data using ODEs and the rewired network and then fitting the simulated data with real data of cancer signalling and cell fate. Most of our predictions are consistent with experimental evidence from literature. Combining the strengths of knowledge-driven and data-driven approaches, our hybrid model can help uncover molecular mechanisms of cancer cell fate at systems level. PMID:25707537

  4. Hollow fiber based quantum cascade laser spectrometer for fast and sensitive drug identification

    NASA Astrophysics Data System (ADS)

    Herbst, J.; Scherer, B.; Ruf, A.; Erb, J.; Lambrecht, A.

    2012-01-01

    Sensitive and fast identification of drugs or drug precursors is important and necessary in scenarios like baggage or container check by customs or police. Fraunhofer IPM is developing a laser spectrometer using external cavity quantum cascade lasers (EC-QCL) to obtain mid-infrared (IR) absorption spectra in the wavelength range of the specific vibrational bands of amphetamines and their precursors. The commercial EC-QCL covers a tuning range of about 225 cm-1 within 1.4 s. The system could be used for different sample types like bulk samples or liquid solutions. A sampling unit evaporates the sample. Because of small sample amounts a 3 m long hollow fiber with an inner volume smaller than 1ml is used as gas cell and wave guide for the laser beam. This setup is suitable as a detector of a gas chromatograph instead of a standard detector (TCD or FID). The advantage is the selective identification of drugs by their IR spectra in addition to the retention time in the gas chromatographic column. In comparison to Fourier Transform IR systems the EC-QCL setup shows a good mechanical robustness and has the advantage of a point light source. Because of the good fiber incoupling performance of the EC-QCL it is possible to use hollow fibers. So, a good absorption signal is achieved because of the long optical path in the small cell volume without significant dilution. In first laboratory experiments a detection limit in the microgram range for pseudo ephedrine is achieved.

  5. Prenatal drug exposures sensitize noradrenergic circuits to subsequent disruption by chlorpyrifos.

    PubMed

    Slotkin, Theodore A; Skavicus, Samantha; Seidler, Frederic J

    2015-12-02

    We examined whether nicotine or dexamethasone, common prenatal drug exposures, sensitize the developing brain to chlorpyrifos. We gave nicotine to pregnant rats throughout gestation at a dose (3mg/kg/day) producing plasma levels typical of smokers; offspring were then given chlorpyrifos on postnatal days 1-4, at a dose (1mg/kg) that produces minimally-detectable inhibition of brain cholinesterase activity. In a parallel study, we administered dexamethasone to pregnant rats on gestational days 17-19 at a standard therapeutic dose (0.2mg/kg) used in the management of preterm labor, followed by postnatal chlorpyrifos. We evaluated cerebellar noradrenergic projections, a known target for each agent, and contrasted the effects with those in the cerebral cortex. Either drug augmented the effect of chlorpyrifos, evidenced by deficits in cerebellar β-adrenergic receptors; the receptor effects were not due to increased systemic toxicity or cholinesterase inhibition, nor to altered chlorpyrifos pharmacokinetics. Further, the deficits were not secondary adaptations to presynaptic hyperinnervation/hyperactivity, as there were significant deficits in presynaptic norepinephrine levels that would serve to augment the functional consequence of receptor deficits. The pretreatments also altered development of cerebrocortical noradrenergic circuits, but with a different overall pattern, reflecting the dissimilar developmental stages of the regions at the time of exposure. However, in each case the net effects represented a change in the developmental trajectory of noradrenergic circuits, rather than simply a continuation of an initial injury. Our results point to the ability of prenatal drug exposure to create a subpopulation with heightened vulnerability to environmental neurotoxicants.

  6. Semiempirical Rules To Determine Drug Sensitivity and Ionization Efficiency in Secondary Ion Mass Spectrometry Using a Model Tissue Sample.

    PubMed

    Vorng, Jean-Luc; Kotowska, Anna M; Passarelli, Melissa K; West, Andrew; Marshall, Peter S; Havelund, Rasmus; Seah, Martin P; Dollery, Colin T; Rakowska, Paulina D; Gilmore, Ian S

    2016-11-15

    There is an increasing need in the pharmaceutical industry to reduce drug failure at late stage and thus reduce the cost of developing a new medicine. Since most drug targets are intracellular, this requires a better understanding of the drug disposition within a cell. Secondary ion mass spectrometry has been identified as a potentially important technique to do this, as it is label-free and allows imaging in 3D with subcellular resolution and recent studies have shown promise for amiodarone. An important analytical parameter is sensitivity, and we measure this in a bovine liver homogenate reference sample for 20 drugs representing important class types relevant to the pharmaceutical industry. We also measure the sensitivity for pure drug and show, for the first time, that the secondary ion mass spectrometry (SIMS) positive ionization efficiency for small molecules is a simple power-law relationship to the log P value. This discovery will be important for advancing the understanding of the SIMS ionization process in small molecules that has, until now, been elusive. This simple relationship is found to hold true for drug doped in the bovine liver homogenate reference sample, except for fluticasone, nicardipine, and sorafenib which suffer from severe matrix suppression. This relationship provides a simple semiempirical method to determine drug sensitivity for positive secondary ions. Furthermore, we show, on chosen models, how the use of different solvents during sample preparation can affect the ionization of analytes.

  7. The Role of More Sensitive Helminth Diagnostics in Mass Drug Administration Campaigns: Elimination and Health Impacts.

    PubMed

    Medley, G F; Turner, H C; Baggaley, R F; Holland, C; Hollingsworth, T D

    2016-01-01

    Diagnostics play a crucial role in determining treatment protocols and evaluating success of mass drug administration (MDA) programmes used to control soil-transmitted helminths (STHs). The current diagnostic, Kato-Katz, relies on inexpensive, reusable materials and can be used in the field, but only trained microscopists can read slides. This diagnostic always underestimates the true prevalence of infection, and the accuracy worsens as the true prevalence falls. We investigate how more sensitive diagnostics would impact on the management and life cycle of MDA programmes, including number of mass treatment rounds, health impact, number of unnecessary treatments and probability of elimination. We use an individual-based model of STH transmission within the current World Health Organization (WHO) treatment guidelines which records individual disability-adjusted life years (DALY) lost. We focus on Ascaris lumbricoides due to the availability of high-quality data on existing diagnostics. We show that the effect of improving the sensitivity of diagnostics is principally determined by the precontrol prevalence in the community. Communities at low true prevalence (<30%) and high true prevalence (>70%) do not benefit greatly from improved diagnostics. Communities with intermediate prevalence benefit greatly from increased chemotherapy application, both in terms of reduced DALY loss and increased probability of elimination. Our results suggest that programmes should be extended beyond school-age children, especially in high prevalence communities. Finally, we argue against using apparent or measured prevalence as an uncorrected proxy for true prevalence.

  8. Development of a temperature-sensitive composite hydrogel for drug delivery applications.

    PubMed

    Ramanan, Ram Mohan Kripa; Chellamuthu, Prithiviraj; Tang, Liping; Nguyen, Kytai T

    2006-01-01

    To develop materials with improved controllability and specificity, we have investigated composite hydrogels with temperature-sensitive properties using photo cross-linking. Specifically, our novel composite materials are composed of nanoparticles made of poly(N-isopropylacrylamide) (PNIPAAm), temperature-sensitive hydrogels, and a photo cross-linker, poly(ethylene glycol) diacrylate (PEGDA). PNIPAAm particles were synthesized by emulsion polymerization and by varying concentration of four main factors: monomers (N-isopropylacrylamide), cross-linkers (N,N'-methylenebisacrylamide), surfactants (sodium dodecyl sulfate, SDS), and initiators (potassium persulfate). We found that the surfactant, SDS, was the most important factor affecting the particle size using the factorial design analysis. Additionally, both nano- and micro-PNIPAAm particles had excellent loading efficiency (>80% of the incubated bovine serum albumin (BSA)), and their release kinetics expressed an initial burst effect followed by a sustained release over time. Furthermore, BSA-loaded PNIPAAm nanoparticles were used to form three-dimensional gel networks by means of a photocuring process using a photo cross-linker, PEGDA, and a photoinitiator, Irgacure-2959 (I-2959). Results from scanning electron microscopy and in vitro BSA release studies from these hydrogels demonstrated that PNIPAAm nanoparticles were embedded inside the PEG polymeric matrix and the composite material was able to release BSA in response to changes in temperature. These PNIPAAm nanoparticle hydrogel networks may have advantages in applications of controlled drug delivery systems because of their temperature sensitivity and their ability of in situ photopolymerization to localize at the specific region in the body.

  9. Implementation of the national tuberculosis guidelines on culture and drug sensitivity testing in Guatemala, 2013.

    PubMed

    Samayoa-Peláez, Maritza; Ayala, Nancy; Yadon, Zaida E; Heldal, Einar

    2016-01-01

    Objective To assess whether the National Tuberculosis Program (NTP) guidelines for culture and drug sensitivity testing (DST) in Guatemala were successfully implemented, particularly in cases of smear-negative pulmonary tuberculosis (TB) or previously treated TB, by documenting notification rates by department (geographic area), disease type and category, and culture and DST results. Methods This was a cross-sectional, operational research study that merged and linked all patients registered by the NTP and the National Reference Laboratory in 2013, eliminating duplicates. The proportions with culture (for new smear negative pulmonary cases) and culture combined with DST (for previously treated patients) were estimated and analyzed by department. Data were analyzed using EpiData Analysis version 2.2. Results There were 3 074 patients registered with TB (all forms), for a case notification rate of 20/100 000 population. Of these, 2 842 had new TB, of which 2 167 (76%) were smear-positive pulmonary TB (PTB), 385 (14%) were smear-negative PTB, and 290 (10%) were extrapulmonary TB. There were 232 (8%) previously treated cases. Case notification rates (all forms) varied by department from 2-68 per 100 000 population, with the highest rates seen in the southwest and northeast part of Guatemala. Of new TB patients, 136 had a culture performed and 55 had DST of which the results were 33 fully sensitive, 9 monoresistant, 3 polyresistant, and 10 multidrug resistant TB (MDR-TB). Only 21 (5%) of new smear-negative PTB patients had cultures. Of 232 previously treated patients, 54 (23%) had a culture and 47 (20%) had DST, of which 29 were fully sensitive, 7 monoresistant, 2 polyresistant, and 9 MDR-TB. Of 22 departments (including the capital), culture and DST was performed in new smear-negative PTB in 7 departments (32%) and in previously treated TB in 13 departments (59%). Conclusions Despite national guidelines, only 5% of smear-negative PTB cases had a culture and only 20% of

  10. Drug screening and grouping by sensitivity with a panel of primary cultured cancer spheroids derived from endometrial cancer.

    PubMed

    Kiyohara, Yumiko; Yoshino, Kiyoshi; Kubota, Satoshi; Okuyama, Hiroaki; Endo, Hiroko; Ueda, Yutaka; Kimura, Toshihiro; Kimura, Tadashi; Kamiura, Shoji; Inoue, Masahiro

    2016-04-01

    Several molecular targeting drugs are being evaluated for endometrial cancer; selecting patients whose cancers are sensitive to these agents is of paramount importance. Previously, we developed the cancer tissue-originated spheroid method for primary cancer cells taken from patients' tumors as well as patient-derived xenografts. In this study, we successfully prepared and cultured cancer tissue-originated spheroids from endometrial cancers. Characteristics of the original tumors were well retained in cancer tissue-originated spheroids including morphology and expression of p53 or neuroendocrine markers. We screened 79 molecular targeting drugs using two cancer tissue-originated spheroid lines derived from endometrioid adenocarcinoma grade 3 and serous adenocarcinoma. Among several hits, we focused on everolimus, a mammalian target of rapamycin complex 1 inhibitor, and YM155, a survivin inhibitor. When sensitivity to everolimus or YM155 was assessed in 12 or 11 cancer tissue-originated spheroids, respectively, from different endometrial cancer patients, the sensitivity varied substantially. The cancer tissue-originated spheroids sensitive to everolimus showed remarkable suppression of proliferation. The phosphorylation status of the mammalian target of rapamycin complex 1 downstream molecules before and after everolimus treatment did not predict the effect of the drug. In contrast, the cancer tissue-originated spheroids sensitive to YM155 showed remarkable cell death. The effect of YM155 was also confirmed in vivo. The histological type correlated with YM155 sensitivity; non-endometrioid adenocarcinomas were sensitive and endometrioid adenocarcinomas were resistant. Non-canonical autophagic cell death was the most likely cause of cell death in a sensitive cancer tissue-originated spheroid. Thus, sensitivity assays using cancer tissue-originated spheroids from endometrial cancers may be useful for screening drugs and finding biomarkers.

  11. Sensitivity to Antimicrobial Drugs of Pseudomonas Aeruginosa Extreme-Resistant Strains Isolated in the Major Hospitals of Central Kazakhstan

    PubMed Central

    Azizov, Ilya S.; Lavrinenko, Alyona V.; Belyaev, Ilya A.; Babenko, Dmitry B.; Shambilova, Natalya A.; Bissenova, Nelya M.

    2017-01-01

    AIM: The article presents the current data on the sensitivity of the main 37 strains of eXtremaly Drugs Resistance (XDR) category to anti-pseudomonas drugs. MATERIAL AND METHODS: The strains were collected during the prospective multicenter study in large multidisciplinary hospitals of Central Kazakhstan. Susceptibility to antimicrobial drugs was carried out by disk method and the serial dilution method with the interpretation of the results according to EUCAST criteria. Detection of carbapenemases gene of VIM, IMP, NDM and GES classes was carried out by PCR method using the commercial kits. RESULTS: All identified carbapenemases were sorted to VIM class and accounted for 63.64%. Resistance to aminoglycoside drugs exceeded 80%. All the strains were susceptible to polymyxin. CONCLUSION: Thus, at the present stage the circulation of P. aeruginosa strains of XDR category continues in major hospitals in Kazakhstan. The strains remain sensitiveness only to polymyxin. PMID:28293307

  12. Spectrophotometric study of the reaction mechanism between DDQ Pi- and iodine sigma-acceptors and chloroquine and pyrimethamine drugs and their determination in pure and in dosage forms.

    PubMed

    Zayed, M A; Khalil, Shaban M; El-Qudaby, Hoda M

    2005-11-01

    Two simple and accurate spectrophotometric methods are presented for the determination of anti-malarial drugs, chloroquine phosphate (CQP) and pyrimethamine (PYM), in pure and in different pharmaceutical preparations. The charge transphere (CT) reactions between CQP and PYM as electron donors and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) pi-acceptor and iodine sigma-acceptor reagents to give highly coloured complex species have been spectrophotometrically studied. The optimum experimental conditions have been studied carefully. Beer' law is obeyed over the concentration range of 1.0-15 microg ml(-1) for CQP and 1.0-40 microg ml(-1) for PYM using I(2) and at 5.0-53 microg ml(-1) for CQP and 1.0-46 microg ml(-1) for PYM using DDQ reagents, respectively. For more accurate results, Ringbom optimum concentration range is calculated and found to be 10-53 and 8-46 microg ml(-1) for CQP and PYM using DDQ, respectively and 5-15 and 8-40 microg ml(-1) for CQP and PYM using iodine, respectively. The Sandell sensitivity is found to be 0.038 and 0.046 g cm(-2) for DDQ method and 0.0078 and 0.056 g cm(-2) for I(2) method for CQP and PYM, respectively which indicates the high sensitivity of both methods. Standard deviation (S.D.=0.012-0.014 and 0.013-0.015) and relative standard deviation (R.S.D.=0.09-1.4 and 1.3-1.5%) (n=5) for DDQ and I(2) methods respectively, refer to the high accuracy and precision of the proposed methods. These results are also confirmed by between day precision of percent recovery of 99-100.6%, and 98-101% for CQP and PYM by DDQ method and 99-102% and 99.2-101.4% for CQP and PYM by I(2) method respectively. These data are comparable to those obtained by British and American pharmacopoeias assay for the determination of CQP and PYM in raw materials and in pharmaceutical preparations.

  13. Spectrophotometric study of the reaction mechanism between DDQ Π- and iodine σ-acceptors and chloroquine and pyrimethamine drugs and their determination in pure and in dosage forms

    NASA Astrophysics Data System (ADS)

    Zayed, M. A.; Khalil, Shaban M.; El-qudaby, Hoda M.

    2005-11-01

    Two simple and accurate spectrophotometric methods are presented for the determination of anti-malarial drugs, chloroquine phosphate (CQP) and pyrimethamine (PYM), in pure and in different pharmaceutical preparations. The charge transphere (CT) reactions between CQP and PYM as electron donors and 2,3-dichloro-5,6-dicyano- p-benzoquinone (DDQ) π-acceptor and iodine σ-acceptor reagents to give highly coloured complex species have been spectrophotometrically studied. The optimum experimental conditions have been studied carefully. Beer' law is obeyed over the concentration range of 1.0-15 μg ml -1 for CQP and 1.0-40 μg ml -1 for PYM using I 2 and at 5.0-53 μg ml -1 for CQP and 1.0-46 μg ml -1 for PYM using DDQ reagents, respectively. For more accurate results, Ringbom optimum concentration range is calculated and found to be 10-53 and 8-46 μg ml -1 for CQP and PYM using DDQ, respectively and 5-15 and 8-40 μg ml -1 for CQP and PYM using iodine, respectively. The Sandell sensitivity is found to be 0.038 and 0.046 g cm -2 for DDQ method and 0.0078 and 0.056 g cm -2 for I 2 method for CQP and PYM, respectively which indicates the high sensitivity of both methods. Standard deviation (S.D. = 0.012-0.014 and 0.013-0.015) and relative standard deviation (R.S.D. = 0.09-1.4 and 1.3-1.5%) ( n = 5) for DDQ and I 2 methods respectively, refer to the high accuracy and precision of the proposed methods. These results are also confirmed by between day precision of percent recovery of 99-100.6%, and 98-101% for CQP and PYM by DDQ method and 99-102% and 99.2-101.4% for CQP and PYM by I 2 method respectively. These data are comparable to those obtained by British and American pharmacopoeias assay for the determination of CQP and PYM in raw materials and in pharmaceutical preparations.

  14. Novel multifunctional pH-sensitive nanoparticles loaded into microbubbles as drug delivery vehicles for enhanced tumor targeting

    PubMed Central

    Lv, Yongjiu; Hao, Lan; Hu, Wenjing; Ran, Ya; Bai, Yan; Zhang, Liangke

    2016-01-01

    This study fabricated novel multifunctional pH-sensitive nanoparticles loaded into microbubbles (PNP-MB) with the combined advantages of two excellent drug delivery vehicles, namely, pH-sensitive nanoparticles and microbubbles. As an antitumor drug, resveratrol (RES) was loaded into acetylated β-cyclodextrin nanoparticles (RES-PNP). The drug-loaded nanoparticles were then encapsulated into the internal space of the microbubbles. The characterization and morphology of this vehicle were investigated through dynamic light scattering and confocal laser scanning microscopy, respectively. In vitro drug release was performed to investigate the pH sensitivity of RES-PNP. The antitumor property of RES-loaded PNP-MB (RES-PNP-MB) was also analyzed in vivo to evaluate the antitumor effect of RES-PNP-MB. Results suggested that PNP exhibited pH sensitivity, and was successfully encapsulated into the microbubbles. RES-PNP-MB exhibit effective tumor growth suppressing in vivo. Therefore, such drug delivery vehicle should be of great attention in tumor therapy. PMID:27378018

  15. Development of pH Sensitive Nanoparticles for Intestinal Drug Delivery Using Chemically Modified Guar Gum Co-Polymer

    PubMed Central

    Varma, Vegesna Naga Sravan Kumar; Shivakumar, Hosakote Gurumalappa; Balamuralidhara, Veerna; Navya, Manne; Hani, Umme

    2016-01-01

    The aim of the research work was to chemically modify guargum (GG) as a pH sensitive co-polymer and formulating intestinal targeting ESO nanoparticles (NPs) using the synthesized co-polymer. Poly acrylamide-grafted-guar gum (PAAm-g-GG) co-polymer was synthesized by free radical polymerization. Chemical modification of PAAm-g-GG by alkaline hydrolysis results in formation of a pH-sensitive co-polymer. The effect of GG and acryl amide (AAm) on grafting was studied. Esomeprazole magnesium (ESO) loaded pH sensitive NPs were prepared by nano-emulsification polymer crosslinking method and characterized. Sixteen formulations were prepared and the concentration of process variables wasvaried to obtain nanoparticles of 200-600 nm. The NPs were found to be homogenous in size distribution. The encapsulation efficiency and drug loading ranged from 33.2% to 50.1% and 12.2% to 17.2% respectively. Particle size, encapsulation efficiency and drug loading increasedalong with co-polymer concentration. In-vitro release studies at pH 1.2 for 2 h, followed by pH 6.8 showed that environment pH significantly affected the drug release. SEM has shown that NPsare spherical with smooth surface. The pH sensitive PAAm-g-GGNPs resisted the initial release of the drug from the drug loaded NPs in acidic pH and delayed the release process to a longer period in alkaline environment. PMID:27610149

  16. Herceptin conjugated PLGA-PHis-PEG pH sensitive nanoparticles for targeted and controlled drug delivery.

    PubMed

    Zhou, Zilan; Badkas, Apurva; Stevenson, Max; Lee, Joo-Youp; Leung, Yuet-Kin

    2015-06-20

    A dual functional nano-scaled drug carrier, comprising of a targeting ligand and pH sensitivity, has been made in order to increase the specificity and efficacy of the drug delivery system. The nanoparticles are made of a tri-block copolymer, poly(d,l lactide-co-glycolide) (PLGA)-b-poly(l-histidine) (PHis)-b-polyethylene glycol (PEG), via nano-precipitation. To provide the nanoparticle feature of endolysosomal escape and pH sensitivity, poly(l-histidine) was chosen as a proton sponge polymer. Herceptin, which specifically binds to HER2 antigen, was conjugated to the nanoparticles through click chemistry. The nanoparticles were characterized via dynamic light scattering (DLS) and transmission electron microscopy (TEM). Both methods showed the sizes of about 100nm with a uniform size distribution. The pH sensitivity was assessed by drug releases and size changes at different pH conditions. As pH decreased from 7.4 to 5.2, the drug release rate accelerated and the size significantly increased. During in vitro tests against human breast cancer cell lines, MCF-7 and SK-BR-3 showed significantly increased uptake for Herceptin-conjugated nanoparticles, as compared to non-targeted nanoparticles. Herceptin-conjugated pH-sensitive nanoparticles showed the highest therapeutic effect, and thus validated the efficacy of a combined approach of pH sensitivity and active targeting.

  17. Dihydrofolate reductase: A potential drug target in trypanosomes and leishmania

    NASA Astrophysics Data System (ADS)

    Zuccotto, Fabio; Martin, Andrew C. R.; Laskowski, Roman A.; Thornton, Janet M.; Gilbert, Ian H.

    1998-05-01

    Dihydrofolate reductase has successfully been used as a drug target in the area of anti-cancer, anti-bacterial and anti-malarial chemotherapy. Little has been done to evaluate it as a drug target for treatment of the trypanosomiases and leishmaniasis. A crystal structure of Leishmania major dihydrofolate reductase has been published. In this paper, we describe the modelling of Trypanosoma cruzi and Trypanosoma brucei dihydrofolate reductases based on this crystal structure. These structures and models have been used in the comparison of protozoan, bacterial and human enzymes in order to highlight the different features that can be used in the design of selective anti-protozoan agents. Comparison has been made between residues present in the active site, the accessibility of these residues, charge distribution in the active site, and the shape and size of the active sites. Whilst there is a high degree of similarity between protozoan, human and bacterial dihydrofolate reductase active sites, there are differences that provide potential for selective drug design. In particular, we have identified a set of residues which may be important for selective drug design and identified a larger binding pocket in the protozoan than the human and bacterial enzymes.

  18. Novel Tween 20 derivatives enable the formation of efficient pH-sensitive drug delivery vehicles for human hepatoblastoma.

    PubMed

    Masotti, Andrea; Vicennati, Paola; Alisi, Anna; Marianecci, Carlotta; Rinaldi, Federica; Carafa, Maria; Ortaggi, Giancarlo

    2010-05-15

    We describe the synthesis, the physicochemical characterization and the biological evaluation of three novel pH-sensitive systems prepared derivatizing polysorbate 20 (Tween 20) with glycine, N-methyl-glycine and N,N-dimethyl-glycine (TW20-GLY, TW20-MMG and TW20-DMG). These derivatives form pH-sensitive vesicles and translocate small molecules into cells. The reported systems are efficient drug delivery systems for human hepatoblastoma cells.

  19. Novel thermo-sensitive hydrogel system with paclitaxel nanocrystals: High drug-loading, sustained drug release and extended local retention guaranteeing better efficacy and lower toxicity.

    PubMed

    Lin, Zhiqiang; Gao, Wei; Hu, Hongxiang; Ma, Kun; He, Bing; Dai, Wenbing; Wang, Xueqing; Wang, Jiancheng; Zhang, Xuan; Zhang, Qiang

    2014-01-28

    As a sustained-release drug depot for localized cancer treatment, in situ thermo-sensitive hydrogel has attracted increasing interests. However, it is currently a big challenge to achieve high drug-loading, sustained and stable drug release, as well as long-term local drug retention simultaneously. We hypothesized that this goal could be accomplished by incorporating the nanocrystals (NCs) of a hydrophobic drug, such as paclitaxel (PTX) into the thermo-sensitive hydrogel (Gel). Hence, a PTX-NCs-Gel system has been constructed with thermo-sensitive Pluronic F127, using PTX-NCs and Taxol® as the controls. Besides, near infra-red agent DiR was used to prepare PTX/DiR hybrid NCs and PTX/DiR hybrid NCs-Gel as well. As a result, this hydrogel system could achieve a high drug loading of PTX up to 3 mg/ml while stabilize the particle size of PTX-NCs significantly compared with PTX-NCs alone. There was no obvious interaction between PTX-NCs and F127. Obviously, PTX/DiR hybrid NCs-Gel presented better localized retention capacity and a much longer retention time in murine 4T1 tumor than PTX/DiR hybrid NCs and Cremophor/ethanol solubilized DiR in vivo. With a linear elimination, over 10% of PTX still remained inside of mouse 4T1 tumor 20 days after intratumoral dosing of PTX-NCs-Gel. Importantly, PTX-NCs exhibited comparable cytotoxity against 4T1 and MCF-7 cells in vitro compared with Taxol®, which could ensure the efficacy of PTX-NCs-Gel. After intratumoral injection, PTX-NCs-Gel was found to be the most effective among all PTX formulations in the 4T1 and MCF-7 tumor-bearing mice models, with much lower system toxicity than Taxol®. In general, it is believed that the novel thermo-sensitive hydrogel system prepared in this study with PTX-NCs affords high drug-loading, sustained and stable drug release, as well as extended drug retention inside of tumor, which results in better therapy and lower toxicity.

  20. Sensitization to the cytotoxicity of melphalan by ethacrynic acid and hyperthermia in drug-sensitive and multidrug-resistant Chinese hamster ovary cells.

    PubMed

    Turcotte, S; Averill-Bates, D A

    2001-09-01

    The ability of physical and pharmacological modulators to increase the cytotoxicity of melphalan was investigated in Chinese hamster ovary cells using a clonogenic cell survival assay. Hyperthermia has potential for use in cancer treatment, particularly as an adjuvant to chemotherapy or radiotherapy. Ethacrynic acid is a glutathione S-transferase inhibitor and also undergoes conjugation with glutathione. Interactions between hyperthermia (41-43 degrees C), ethacrynic acid and melphalan were evaluated in multidrug-resistant (CH(R)C5) cells with overexpression of P-glycoprotein (33.69-fold), and in drug-sensitive (AuxB1) cells. GST alpha was expressed at a higher level (3.65-fold) in CH(R)C5 cells than in sensitive cells, whereas levels of isoforms pi and mu were the same. GST pi was the most highly expressed isoform in the two cell populations. Ethacrynic acid was cytotoxic at elevated temperatures, while it caused little or no cytotoxicity at 37 degrees C. This effect occurred in drug-resistant and drug-sensitive cells, and attributes thermosensitizing properties to ethacrynic acid. Ethacrynic acid (20 microM) alone did not alter the cytotoxicity of melphalan at 37 degrees C. Hyperthermia potentiated drug cytotoxicity in cells, both with and without ethacrynic acid treatment. Ethacrynic acid could be useful in cancer treatment by acting as a thermosensitizer when combined with heat and by enhancing the cytotoxicity of melphalan at elevated temperatures. A major advantage arising from the use of regional hyperthermia is the ability to target drug cytotoxicity to the tumor volume. A useful finding is that ethacrynic acid, heat and/or melphalan are also effective against multidrug-resistant cells with overexpression of P-glycoprotein.

  1. Asynchronous magnetic bead rotation (AMBR) micro-viscometer for rapid, sensitive and label-free studies of bacterial growth and drug sensitivity

    PubMed Central

    Sinn, Irene; Albertson, Theodore; Kinnunen, Paivo; Breslauer, David N.; McNaughton, Brandon H.; Burns, Mark A.; Kopelman, Raoul

    2012-01-01

    The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and encourages the administration of wide spectrum antibiotics, thus resulting in alarming increases of multi-drug resistant pathogens. A method for faster detection of bacterial proliferation presents one avenue towards addressing this global concern. We report on a label-free asynchronous magnetic bead rotation (AMBR) based viscometry method that rapidly detects bacterial growth and determines drug sensitivity by measuring changes in the suspension’s viscosity. With this platform, we observed the growth of a uropathogenic Escherichia coli isolate, with an initial concentration of 50 cells per drop, within 20 minutes; in addition, we determined the gentamicin minimum inhibitory concentration (MIC) of the E. coli isolate within 100 minutes. We thus demonstrated a label-free, micro-viscometer platform that can measure bacterial growth and drug susceptibility more rapidly, with lower initial bacterial counts than existing commercial systems, and potentially with any microbial strains. PMID:22507307

  2. A microfluidic platform for high-sensitivity, real-time drug screening on C. elegans and parasitic nematodes†

    PubMed Central

    Carr, John A.; Parashar, Archana; Gibson, Richard; Robertson, Alan P.; Martin, Richard J.; Pandey, Santosh

    2013-01-01

    This paper describes a new microfluidic platform for screening drugs and their dose response on the locomotion behavior of free living nematodes and parasitic nematodes. The system offers a higher sensitivity drug screening chip which employs a combination of existing and newly developed methods. Real-time observation of the entire drug application process (i.e. the innate pre-exposure locomotion, the transient response during drug exposure and the time-resolved, post-exposure behavior) at a single worm resolution is made possible. The chip enables the monitoring of four nematode parameters (number of worms responsive, number of worms leaving the drug well, average worm velocity and time until unresponsiveness). Each parameter generates an inherently different dose response; allowing for a higher resolution when screening for resistance. We expect this worm chip could be used as a robust cross species, cross drug platform. Existing nematode motility and migration assays do not offer this level of sophistication. The device comprises two principal components: behavioral microchannels to study nematode motility and a drug well for administering the dose and observing drug effects as a function of exposure time. The drug screening experiment can be described by three main steps: (i) ‘pre-exposure study’ – worms are inserted into the behavioral channels and their locomotion is characterized, (ii) ‘dose exposure’ – worms are guided from the behavioral microchannels into the drug well and held for a predefined time, during which time their transient response to the dose is characterized and (iii) ‘post-exposure study’ – worms are guided back into the behavioral microchannels where their locomotion (i.e. their time-resolved response to the dose) is characterized and compared to pre-exposure motility. The direction of nematodes’ movement is reliably controlled by the application of an electric field within a defined range. Control experiments (e.g. in

  3. [Sensitivity to drugs of Escherichia coli strains isolated from poultry with coli septicemia].

    PubMed

    Giurov, B

    1985-01-01

    Investigations were carried out into the susceptibility of a total of 223 strains of Escherichia coli to therapeutic agents with the employment of the disk diffusion method. The organisms were isolated from internal organs and bone marrow of birds died of coli septicaemia. The serologic classification of the strains was defined with the use of 88 anti-group OK-agglutinating sera obtained through hyperimmunization of rabbits with the following Escherichia coli serotypes: 01-063, 068, 071, 073, 075, 078, 086, 0101, 0103, 0111-0114, 0119, 0124, 0129, 0135-0141, 0146, 0147, and 0149. It was found that serologically the strains referred as follows: 01-41 strains, 02-70 strains, 04-2 strains, 08-3 strains, 026-1 strain, 078-70 strains, 0111-2 strains, 0103-1 strain, 0141-1 strain. The number of untypable strains amounted to 32. Highest number of strains proved sensitive to colistin--96.06%, the remaining drugs following in a descending order: flumequine--95.65%, apramycin - 95.5%, gentamycin--93.72%, amoxicillin--93,8%, amikacin--88.57%, carbenicillin--86.88%, furazolidone--83,13%, and kanamycin--79.36%. High was the percent of strains resistant to tetracycline--66.17%, spectinomycin--61.67%, ampicillin--51.12%, chloramphenicol--50.23%, and streptomycin--44.84%.

  4. Why Hospital Pharmacists Have Failed to Manage Antimalarial Drugs Stock-Outs in Pakistan? A Qualitative Insight

    PubMed Central

    Hassali, Mohamed Azmi Ahmad; Shafie, Asrul Akmal; Hussain, Azhar

    2013-01-01

    Purpose. This study aimed to explore the perceptions of hospital pharmacists towards drug management and reasons underlying stock-outs of antimalarial drugs in Pakistan. Methods. A qualitative study was designed to explore the perceptions of hospital pharmacists regarding drug management and irrational use of antimalarial drugs in two major cities of Pakistan, namely, Islamabad (national capital) and Rawalpindi (twin city). Semistructured interviews were conducted with 16 hospital pharmacists using indepth interview guides at a place and time convenient for the respondents. Interviews, which were audiotaped and transcribed verbatim, were evaluated by thematic content analysis and by other authors' analysis. Results. Most of the respondents were of the view that financial constraints, inappropriate drug management, and inadequate funding were the factors contributing toward the problem of antimalarial drug stock-outs in healthcare facilities of Pakistan. The pharmacists anticipated that prescribing by nonproprietary names, training of health professionals, accepted role of hospital pharmacist in drug management, implementation of essential drug list and standard treatment guidelines for malaria in the healthcare system can minimize the problem of drug stock outs in healthcare system of Pakistan. Conclusion. The current study showed that all the respondents in the two cities agreed that hospital pharmacist has failed to play an effective role in efficient management of anti-malarial drugs stock-outs. PMID:24223321

  5. Preparation of end-capped pH-sensitive mesoporous silica nanocarriers for on-demand drug delivery.

    PubMed

    Moreira, André F; Gaspar, Vítor M; Costa, Elisabete C; de Melo-Diogo, Duarte; Machado, Paulo; Paquete, Catarina M; Correia, Ilídio J

    2014-11-01

    Nanocarriers with a pH responsive behavior are receiving an ever growing attention due to their potential for promoting on-demand drug release and thus increase the therapeutic effectiveness of anti-tumoral pharmaceutics. However, the majority of these systems require costly, time-consuming and complex chemical modifications of materials or drugs to synthesize nanoparticles with pH triggered release. Herein, the development of dual drug loaded pH-responsive mesoporous silica nanoparticles (MSNs) with a calcium carbonate-based coating is presented as an effective alternative. This innovative approach allowed the loading of a non-steroidal anti-inflammatory drug (Ibuprofen) and Doxorubicin, with high efficiency. The resulting dual drug loaded MSNs have spherical morphology and a mean size of 171nm. Our results indicate that under acidic conditions the coating disassembles and the drugs are rapidly released, whereas at physiologic pH the release is slower and gradually increases with time. Furthermore, an improved cytotoxic effect was obtained for Doxorubicin-Ibuprofen MSNs coated with CaCO3 in comparison with non-coated particles. The cytotoxic effect of dual loaded carbonate coated particles, was similar to that of Doxorubicin+Ibuprofen free drug administration at 72h, even with the delivery of a significantly lower amount of drug by MSNs-CaCO3. These results suggest that the carbonate coating of MSNs is a promising approach to create a pH-sensitive template for a delivery system with application in cancer therapy.

  6. Green fabricated reduced graphene oxide: evaluation of its application as nano-carrier for pH-sensitive drug delivery.

    PubMed

    Ma, Naxin; Zhang, Baohua; Liu, Jing; Zhang, Pei; Li, Zhonghao; Luan, Yuxia

    2015-12-30

    A green and mild approach for the preparation of reduced graphene oxide (rGO) was proposed by using riboflavin-5'-phosphate sodium salt dihydrate as a reducing reagent and stabilizer without any other reagent. The fabricated nano-rGO was systematically evaluated for its application as nano-carrier for pH-sensitive drug delivery. The hemolytic toxicity test indicated the as-prepared nano-rGO had negligible hemolytic activity, which demonstrating its safety in drug delivery system. Doxorubicin hydrochloride (DOX) as a model drug was successfully attached onto the surface of nano-rGO via strong π-π stacking interaction. Compared with common carriers, the obtained DOX-loaded nano-rGO nanohybrid exhibited characteristics of high drug loading content, good stability, pH-sensitive and sustainable release of drugs. Cytotoxicity assay results suggested such nanohybrid exhibited effective cytotoxicity to MCF-7 and A549 cells by nonspecific endocytosis mechanism. Therefore, the present green fabricated rGO could be a good candidate as an ideal nano-carrier for drug delivery and controlled release.

  7. Systematic assessment of multi-gene predictors of pan-cancer cell line sensitivity to drugs exploiting gene expression data

    PubMed Central

    Nguyen, Linh; Dang, Cuong C; Ballester, Pedro J.

    2017-01-01

    Background: Selected gene mutations are routinely used to guide the selection of cancer drugs for a given patient tumour. Large pharmacogenomic data sets, such as those by Genomics of Drug Sensitivity in Cancer (GDSC) consortium, were introduced to discover more of these single-gene markers of drug sensitivity. Very recently, machine learning regression has been used to investigate how well cancer cell line sensitivity to drugs is predicted depending on the type of molecular profile. The latter has revealed that gene expression data is the most predictive profile in the pan-cancer setting. However, no study to date has exploited GDSC data to systematically compare the performance of machine learning models based on multi-gene expression data against that of widely-used single-gene markers based on genomics data. Methods: Here we present this systematic comparison using Random Forest (RF) classifiers exploiting the expression levels of 13,321 genes and an average of 501 tested cell lines per drug. To account for time-dependent batch effects in IC 50 measurements, we employ independent test sets generated with more recent GDSC data than that used to train the predictors and show that this is a more realistic validation than standard k-fold cross-validation. Results and Discussion: Across 127 GDSC drugs, our results show that the single-gene markers unveiled by the MANOVA analysis tend to achieve higher precision than these RF-based multi-gene models, at the cost of generally having a poor recall (i.e. correctly detecting only a small part of the cell lines sensitive to the drug). Regarding overall classification performance, about two thirds of the drugs are better predicted by the multi-gene RF classifiers. Among the drugs with the most predictive of these models, we found pyrimethamine, sunitinib and 17-AAG. Conclusions: Thanks to this unbiased validation, we now know that this type of models can predict in vitro tumour response to some of these drugs. These models

  8. Anticancer drug clustering based on proteomic profiles and a sensitivity database in a lung cancer cell line panel

    PubMed Central

    HINO, MITSUNORI; MATSUDA, KUNIKO; MIYANAGA, AKIHIKO; KURIBAYASI, HIDEHIKO; MIZUTANI, HIDEAKI; NORO, RINTARO; MINEGISHI, YUJI; OKANO, TETSUYA; SEIKE, MASAHIRO; KAWAKAMI, AKIKO; YOSHIMURA, AKINOBU; OGAWA, NAOKI; UESAKA, HARUKA; KUDOH, SHOJI; GEMMA, AKIHIKO

    2010-01-01

    Previously, we performed a molecular pharmacological study that applied a combination of DNA microarray-based gene expression profiling and drug sensitivity tests in vitro with a view to designing an improved chemotherapeutic strategy for advanced lung cancer. Utilizing recent key technological advances in proteomics, particularly antibody array-based methodologies, the current study aimed to examine the benefit of protein expression profiling in an analogous molecular pharmacological context. We performed protein expression analysis in a panel of lung cancer cell lines via an antibody array approach. Using a modified NCI program, we related cell line-specific proteomic profiles to the previously determined cytotoxic activity of a selection of commonly used anticancer agents, namely docetaxel, paclitaxel, gemcitabine, vinorelbine, 5-fluorouracil (5-FU), SN38, cisplatin (CDDP) and carboplatin (CBDCA). In addition, we compared these results with those obtained from our prior DNA microarray-based transcriptomic study. In our expression-drug correlation analysis using antibody array, gemcitabine consistently belonged to an isolated cluster. Docetaxel, paclitaxel, 5-FU, SN38, CBDCA and CDDP were gathered together into one large cluster. These results coincided with those generated by the prior transcriptomic study. Various genes were commonly listed that differentiated gemcitabine from the others. The identified factors associated with drug sensitivities were different between both analyses. Our proteomic profiling data provided confirmation of the previous transcript expression-drug sensitivity correlation analysis. These results suggest that chemotherapy regimens that include gemcitabine should be evaluated in second-line chemotherapy in cases where the first-line chemotherapy did not include this drug. Protein expression-drug sensitivity correlations in lung cancer cells in vitro may provide useful information in determining the most appropriate therapeutic options

  9. Successful analysis of anticancer drug sensitivity by CD-DST using pleural fluid and ascites from patients with advanced ovarian cancer: case reports.

    PubMed

    Kawaguchi, Makiko; Banno, Kouji; Susumu, Nobuyuki; Yanokura, Megumi; Kuwabara, Yoshiko; Hirao, Nobumaru; Tsukazaki, Katsumi; Nozawa, Shiro

    2005-01-01

    In vitro anticancer drug sensitivity tests have been performed for various types of cancers, and a relationship with clinical response has been observed. The collagen gel droplet-embedded culture drug sensitivity test (CD-DST) is a new in vitro anticancer drug sensitivity test by Yabushita et al., recently reported to be useful in ovarian cancer. CD-DST allows analysis of a small number of cells, compared to other anticancer drug sensitivity tests. Here, we report a successful analysis of anticancer drug sensitivity by CD-DST using cancerous ascites and pleural fluid samples from 2 patients with advanced ovarian cancer. To our knowledge, this is only the second report of the application of CD-DST in ovarian cancer, and our results suggest that CD-DST could be helpful in the selection of anticancer drugs for neoadjuvant chemotherapy in advanced ovarian cancer.

  10. Temperature-sensitive polymer-coated magnetic nanoparticles as a potential drug delivery system for targeted therapy of thyroid cancer.

    PubMed

    Koppolu, Bhanuprasanth; Bhavsar, Zarna; Wadajkar, Aniket S; Nattama, Sivaniarvindpriya; Rahimi, Maham; Nwariaku, Fiemu; Nguyen, Kytai T

    2012-12-01

    The objective of this work was to develop and investigate temperature-sensitive poly(N-isopropylacrylamide-acrylamide-allylamine)-coated iron oxide magnetic nanoparticles (TPMNPs) as possible targeted drug carriers for treatments of advanced thyroid cancer (ATC). These nanoparticles were prepared by free radical polymerization of monomers on the surface of silane-coupled iron oxide nanoparticles. In vitro studies demonstrated that TPMNPs were cytocompatible and effectively taken up by cancer cells in a dose-dependent manner. An external magnetic field significantly increased nanoparticle uptake, especially when cells were exposed to physiological flow conditions. Drug loading and release studies using doxorubicin confirmed the temperature-responsive release of drugs from nanoparticles. In addition, doxorubicin-loaded nanoparticles significantly killed ATC cells when compared to free doxorubicin. The in vitro results indicate that TPMNPs have potential as targeted and controlled drug carriers for thyroid cancer treatment.

  11. Development of a Sensitive Outcome for Economical Drug Screening for Progressive Multiple Sclerosis Treatment

    PubMed Central

    Kosa, Peter; Ghazali, Danish; Tanigawa, Makoto; Barbour, Chris; Cortese, Irene; Kelley, William; Snyder, Blake; Ohayon, Joan; Fenton, Kaylan; Lehky, Tanya; Wu, Tianxia; Greenwood, Mark; Nair, Govind; Bielekova, Bibiana

    2016-01-01

    Therapeutic advance in progressive multiple sclerosis (MS) has been very slow. Based on the transformative role magnetic resonance imaging (MRI) contrast-enhancing lesions had on drug development for relapsing-remitting MS, we consider the lack of sensitive outcomes to be the greatest barrier for developing new treatments for progressive MS. The purpose of this study was to compare 58 prospectively acquired candidate outcomes in the real-world situation of progressive MS trials to select and validate the best-performing outcome. The 1-year pre-treatment period of adaptively designed IPPoMS (ClinicalTrials.gov #NCT00950248) and RIVITaLISe (ClinicalTrials.gov #NCT01212094) Phase II trials served to determine the primary outcome for the subsequent blinded treatment phase by comparing 8 clinical, 1 electrophysiological, 1 optical coherence tomography, 7 MRI volumetric, 9 quantitative T1 MRI, and 32 diffusion tensor imaging MRI outcomes. Fifteen outcomes demonstrated significant progression over 1 year (Δ) in the predetermined analysis and seven out of these were validated in two independent cohorts. Validated MRI outcomes had limited correlations with clinical scales, relatively poor signal-to-noise ratios (SNR) and recorded overlapping values between healthy subjects and MS patients with moderate-severe disability. Clinical measures correlated better, even though each reflects a somewhat different disability domain. Therefore, using machine-learning techniques, we developed a combinatorial weight-adjusted disability score (CombiWISE) that integrates four clinical scales: expanded disability status scale (EDSS), Scripps neurological rating scale, 25 foot walk and 9 hole peg test. CombiWISE outperformed all clinical scales (Δ = 9.10%; p = 0.0003) and all MRI outcomes. CombiWISE recorded no overlapping values between healthy subjects and disabled MS patients, had high SNR, and predicted changes in EDSS in a longitudinal assessment of 98 progressive MS

  12. Enhanced sensitivity to drugs of abuse and palatable foods following maternal overnutrition

    PubMed Central

    Peleg-Raibstein, D; Sarker, G; Litwan, K; Krämer, S D; Ametamey, S M; Schibli, R; Wolfrum, C

    2016-01-01

    Epidemiological studies have shown an association between maternal overnutrition and increased risk of the progeny for the development of obesity as well as psychiatric disorders. Animal studies have shown results regarding maternal high-fat diet (HFD) and a greater risk of the offspring to develop obesity. However, it still remains unknown whether maternal HFD can program the central reward system in such a way that it will imprint long-term changes that will predispose the offspring to addictive-like behaviors that may lead to obesity. We exposed female dams to either laboratory chow or HFD for a period of 9 weeks: 3 weeks before conception, during gestation and lactation. Offspring born to either control or HFD-exposed dams were examined in behavioral, neurochemical, neuroanatomical, metabolic and positron emission tomography (PET) scan tests. Our results demonstrate that HFD offspring compared with controls consume more alcohol, exhibit increased sensitivity to amphetamine and show greater conditioned place preference to cocaine. In addition, maternal HFD leads to increased preference to sucrose as well as to HFD while leaving the general feeding behavior intact. The hedonic behavioral alterations are accompanied by reduction of striatal dopamine and by increased dopamine 2 receptors in the same brain region as evaluated by post-mortem neurochemical, immunohistochemical as well as PET analyses. Taken together, our data suggest that maternal overnutrition predisposes the offspring to develop hedonic-like behaviors to both drugs of abuse as well as palatable foods and that these types of behaviors may share common neuronal underlying mechanisms that can lead to obesity. PMID:27701408

  13. A Disposable Microfluidic Device for Controlled Drug Release from Thermal-Sensitive Liposomes by High Intensity Focused Ultrasound

    PubMed Central

    Meng, Long; Deng, Zhiting; Niu, Lili; Li, Fei; Yan, Fei; Wu, Junru; Cai, Feiyan; Zheng, Hairong

    2015-01-01

    The drug release triggered thermally by high intensity focused ultrasound (HIFU) has been considered a promising drug delivery strategy due to its localized energy and non-invasive characters. However, the mechanism underlying the HIFU-mediated drug delivery remains unclear due to its complexity at the cellular level. In this paper, micro-HIFU (MHIFU) generated by a microfluidic device is introduced which is able to control the drug release from temperature-sensitive liposomes (TSL) and evaluate the thermal and mechanical effects of ultrasound on the cellular drug uptake and apoptosis. By simply adjusting the input electrical signal to the device, the temperature of sample can be maintained at 37 °C, 42 °C and 50 °C with the deviation of ± 0.3 °C as desired. The flow cytometry results show that the drug delivery under MHIFU sonication leads to a significant increase in apoptosis compared to the drug release by incubation alone at elevated temperature of 42 °C. Furthermore, increased squamous and protruding structures on the surface membrane of cells were detected by atomic force microscopy (AFM) after MHIFU irradiation of TSL. We demonstrate that compared to the routine HIFU treatment, MHIFU enables monitoring of in situ interactions between the ultrasound and cell in real time. Furthermore, it can quantitatively analyze and characterize the alterations of the cell membrane as a function of the treatment time. PMID:26379786

  14. Morphometric and colorimetric analyses of human tumor cell line growth and drug sensitivity in soft agar culture.

    PubMed

    Alley, M C; Pacula-Cox, C M; Hursey, M L; Rubinstein, L R; Boyd, M R

    1991-02-15

    Previous studies have demonstrated the suitability of image analysis of tetrazolium-stained colonies to assess growth and drug sensitivity of human tumor cells cultivated in soft agar culture. In the present study, the potential utility of colorimetric analysis to expedite experimental drug evaluations using human tumor cell lines was investigated. The same culture dishes were assessed by image analysis and by formazan colorimetry for purposes of comparing multiple methods of measuring growth as well as growth inhibition. Replicate cultures treated with 2-(p-iodonitrophenyl)-3-p-nitrophenyl-5-phenyltetrazolium chloride or 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide exhibited nearly identical colony count and volume indices as well as excellent correlation in colorimetric end points. Colony-forming unit volume analysis versus colorimetric assessment of the same cultures following dimethyl sulfoxide extraction of protamine sulfate-rinsed, dried soft agar cultures exhibited excellent linear correlation for both growth (Pearson r ranging from 0.95 to 1.00) and drug sensitivity (Pearson r ranging from 0.90 to 0.99, and Spearman r ranging from 0.82 to 0.97) and similar drug sensitivity profiles. Results of the current investigation indicate that end points of soft agar culture remain stable for a period of at least 2 weeks following assay termination. In addition, a colorimetric detection range of 1.3-2.2 log units permits determinations of survival levels ranging from 100 to 5% of respective control levels. Colorimetric analysis is anticipated to expedite soft agar colony formation assay evaluations (a) by reducing the need to use the more rigorous and time-consuming image analysis procedures to measure activity in preliminary drug sensitivity assays and (b) by permitting the determination of effective concentration ranges of new experimental agents for subsequent, more detailed investigations.

  15. miR-181b increases drug sensitivity in acute myeloid leukemia via targeting HMGB1 and Mcl-1.

    PubMed

    Lu, Fei; Zhang, Jingru; Ji, Min; Li, Peng; Du, Yahui; Wang, Hongchun; Zang, Shaolei; Ma, Daoxin; Sun, Xiulian; Ji, Chunyan

    2014-07-01

    Multidrug resistance (MDR) remains the major cause of disease relapse and poor prognosis in adults with acute myeloid leukemia (AML). Emerging evidence shows that drug resistance not only exists against conventional chemotherapeutic drugs, but also limits the efficacy of new biological agents. Therefore, it is important to elucidate the mechanisms through which AML patients develop drug resistance. MicroRNAs have been shown to play an important role in regulating the chemotherapy resistance in AML. A detailed understanding of the mechanisms of microRNA that are clinically relevant in AML may enhance our ability to predict and overcome drug resistance. Here, we demonstrated, for the first time, that miR-181b was decreased significantly in human multidrug-resistant leukemia cells and relapsed/refractory AML patient samples. Overexpression of miR-181b increased the sensitivity of leukemia cells to cytotoxic chemotherapeutic agents and promoted drug-induced apoptosis. Moreover, miR-181b inhibited HMGB1 and Mcl-1 expression by direct binding to their 3'-untranslated regions. In addition, HMGB1 was expressed at high levels in relapsed/refractory AML patients and suppression of HMGB1 via RNA interference sensitized multidrug-resistant leukemia cells to chemotherapy and induced apoptosis. In conclusion, these results provide a strong rationale for the development of miR-181b-based therapeutic strategies for the enhancement of efficacy in AML treatment.

  16. A sensitive quantum dots-based "OFF-ON" fluorescent sensor for ruthenium anticancer drugs and ctDNA.

    PubMed

    Huang, Shan; Zhu, Fawei; Qiu, Hangna; Xiao, Qi; Zhou, Quan; Su, Wei; Hu, Baoqing

    2014-05-01

    In this contribution, a simple and sensitive fluorescent sensor for the determination of both the three ruthenium anticancer drugs (1 to 3) and calf thymus DNA (ctDNA) was established based on the CdTe quantum dots (QDs) fluorescence "OFF-ON" mode. Under the experimental conditions, the fluorescence of CdTe QDs can be effectively quenched by ruthenium anticancer drugs because of the surface binding of these drugs on CdTe QDs and the subsequent photoinduced electron transfer (PET) process from CdTe QDs to ruthenium anticancer drugs, which render the system into fluorescence "OFF" status. The system can then be "ON" after the addition of ctDNA which brought the restoration of CdTe QDs fluorescence intensity, since ruthenium anticancer drugs broke away from the surface of CdTe QDs and inserted into double helix structure of ctDNA. The fluorescence quenching effect of the CdTe QDs-ruthenium anticancer drugs systems was mainly concentration dependent, which could be used to detect three ruthenium anticancer drugs. The limits of detection were 5.5 × 10(-8) M for ruthenium anticancer drug 1, 7.0 × 10(-8) M for ruthenium anticancer drug 2, and 7.9× 10(-8) M for ruthenium anticancer drug 3, respectively. The relative restored fluorescence intensity was directly proportional to the concentration of ctDNA in the range of 1.0 × 10(-8) M ∼ 3.0 × 10(-7) M, with a correlation coefficient (R) of 0.9983 and a limit of detection of 1.1 × 10(-9) M. The relative standard deviation (RSD) for 1.5 × 10(-7) M ctDNA was 1.5% (n = 5). There was almost no interference to some common chemical compounds, nucleotides, amino acids, and proteins. The proposed method was applied to the determination of ctDNA in three synthetic samples with satisfactory results. The possible reaction mechanism of CdTe QDs fluorescence "OFF-ON" was further investigated. This simple and sensitive approach possessed some potential applications in the investigation of interaction between drug molecules and DNA.

  17. Patch testing and cross sensitivity study of adverse cutaneous drug reactions due to anticonvulsants: A preliminary report

    PubMed Central

    Shiny, T N; Mahajan, Vikram K; Mehta, Karaninder S; Chauhan, Pushpinder S; Rawat, Ritu; Sharma, Rajni

    2017-01-01

    AIM To evaluate the utility of patch test and cross-sensitivity patterns in patients with adverse cutaneous drug reactions (ACDR) from common anticonvulsants. METHODS Twenty-four (M:F = 13:11) patients aged 18-75 years with ACDR from anticonvulsants were patch tested 3-27 mo after complete recovery using carbamazepine, phenytoin, phenobarbitone, lamotrigine, and sodium valproate in 10%, 20% and 30% conc. in pet. after informed consent. Positive reactions persisting on D3 and D4 were considered significant. RESULTS Clinical patterns were exanthematous drug rash with or without systemic involvement (DRESS) in 18 (75%), Stevens-Johnsons syndrome/toxic epidermal necrolysis (SJS/TEN) overlap and TEN in 2 (8.3%) patients each, SJS and lichenoid drug eruption in 1 (4.2%) patient each, respectively. The implicated drugs were phenytoin in 14 (58.3%), carbamazepine in 9 (37.5%), phenobarbitone in 2 (8.3%), and lamotrigine in 1 (4.7%) patients, respectively. Twelve (50%) patients elicited positive reactions to implicated drugs; carbamazepine in 6 (50%), phenytoin alone in 4 (33.3%), phenobarbitone alone in 1 (8.3%), and both phenytoin and phenobarbitone in 1 (8.33%) patients, respectively. Cross-reactions occurred in 11 (92%) patients. Six patients with carbamazepine positive patch test reaction showed cross sensitivity with phenobarbitone, sodium valproate and/or lamotrigine. Three (75%) patients among positive phenytoin patch test reactions had cross reactions with phenobarbitone, lamotrigine, and/or valproate. CONCLUSION Carbamazepine remains the commonest anticonvulsant causing ACDRs and cross-reactions with other anticonvulsants are possible. Drug patch testing appears useful in DRESS for drug imputability and cross-reactions established clinically.

  18. pH- and temperature-sensitive polymeric microspheres for drug delivery: the dissolution of copolymers modulates drug release.

    PubMed

    Fundueanu, Gheorghe; Constantin, Marieta; Stanciu, Cristina; Theodoridis, Georgios; Ascenzi, Paolo

    2009-12-01

    Most pH-/temperature-responsive polymers for controlled release of drugs are used as cross-linked hydrogels. However, the solubility properties of the linear polymers below and above the lower critical solution temperature (LCST) are not exploited. Here, the preparation and characterization of poly (N-isopropylacrylamide-co-methacrylic acid-co-methyl methacrylate) (poly (NIPAAm-co-MA-co-MM)) and poly (N-isopropylacrylamide-co-acrylamide) (poly (NIPAAm-co-AAm)), known as "smart" polymers (SP), is reported. Both poly (NIPAAm-co-MA-co-MM) and poly (NIPAAm-co-AAm) display pH- and temperature-responsive properties. Poly (NIPAAm-co-MA-co-MM) was designed to be insoluble in the gastric fluid (pH = 1.2), but soluble in the intestinal fluid (pH = 6.8 and 7.4), at the body temperature (37 degrees C). Poly (NIPAAm-co-AAm) was designed to have a lower critical solution temperature (LCST) corresponding to 37 degrees C at pH = 7.4, therefore it is not soluble above the LCST. The solubility characteristics of these copolymers were exploited to modulate the rate of release of drugs by changing pH and/or temperature. These copolymers were solubilized with hydrophobic cellulose acetate butyrate (CAB) and vitamin B(12) (taken as a water soluble drug model system) in an acetone/methanol mixture and dispersed in mineral oil. By a progressive evaporation of the solvent, the liquid droplets were transformed into loaded CAB/SP microspheres. Differential scanning calorimetric studies and scanning electron microscopy analysis demonstrated that the polymeric components of the microspheres precipitated separately during solvent evaporation forming small microdomains. Moreover, vitamin B(12) was found to be molecularly dispersed in both microdomains with no specific affinity for any polymeric component of microspheres. The release of vitamin B(12) was investigated as a function of temperature, pH, and the CAB/SP ratio.

  19. Growth Hormone Receptor Knockdown Sensitizes Human Melanoma Cells to Chemotherapy by Attenuating Expression of ABC Drug Efflux Pumps.

    PubMed

    Basu, Reetobrata; Baumgaertel, Nicholas; Wu, Shiyong; Kopchick, John J

    2017-03-14

    Melanoma remains one of the most therapy-resistant forms of human cancer despite recent introductions of highly efficacious targeted therapies. The intrinsic therapy resistance of human melanoma is largely due to abundant expression of a repertoire of xenobiotic efflux pumps of the ATP-binding cassette (ABC) transporter family. Here, we report that GH action is a key mediator of chemotherapeutic resistance in human melanoma cells. We investigated multiple ABC efflux pumps (ABCB1, ABCB5, ABCB8, ABCC1, ABCC2, ABCG1, and ABCG2) reportedly associated with melanoma drug resistance in different human melanoma cells and tested the efficacy of five different anti-cancer compounds (cisplatin, doxorubicin, oridonin, paclitaxel, vemurafenib) with decreased GH action. We found that GH treatment of human melanoma cells upregulates expression of multiple ABC transporters and increases the EC50 of melanoma drug vemurafenib. Also, vemurafenib-resistant melanoma cells had upregulated levels of GH receptor (GHR) expression as well as ABC efflux pumps. GHR knockdown (KD) using siRNA in human melanoma cells treated with sub-EC50 doses of anti-tumor compounds resulted in significantly increased drug retention, decreased cell proliferation and increased drug efficacy, compared to mock-transfected controls. Our set of findings identify an unknown mechanism of GH regulation in mediating melanoma drug resistance and validates GHR as a unique therapeutic target for sensitizing highly therapy-resistant human melanoma cells to lower doses of anti-cancer drugs.

  20. In vitro sensitivities to antimicrobial drugs of ureaplasmas isolated from the bovine respiratory tract, genital tract and eye.

    PubMed

    Kishima, M; Hashimoto, K

    1979-09-01

    The sensitivity to 18 antimicrobial drugs was examined for 66 strains of Ureaplasma sp isolated from respiratory tracts of calves suffering from enzootic pneumonia, urinary tracts of bulls and eyes of cows suffering from infectious bovine kerato-conjunctivitis. Furamizole, tiamulin fumarate, erythromycin lactobionate, malidomycin C, doxycycline hydrochloride, kitasamycin tartrate, tylosin tartrate, T-2636C, tetracycline hydrochloride, oxytetracycline hydrochloride, chlortetracycline hydrochloride, oleandomycin phosphate, furazolidone, spiramycin adipate, chloramphenicol and thiophenicol showed strong inhibiting activity on all the test strains. Among them, furamizole, tiamulin fumarate and erythromycin lactobionate were most active. Kanamycin sulphate showed weak activity on all the strains tested. The differences in origin of the test strains did not affect their sensitivity to any of the drugs.

  1. Regulation of mRNA expression in drug-sensitive and drug-resistant gastric carcinoma cells is independent of YB-1 expression.

    PubMed

    Kurucz, Reka; Belian, Elisa; Treue, Denise; Lage, Hermann

    2010-02-01

    Y-Box protein 1 (YB-1) is a multifunctional cellular protein expressed in a range of mammalian cells, including human cancer cells. It is involved in the regulation of various genes including cancer-associated genes, but the full range of target genes and regulatory mechanisms have not been fully elucidated. To identify global mRNA expression patterns that are potentially regulated by YB-1, a previously established and well-characterized cell model derived from drug-sensitive (EPG85-257P/tetR/YB-1) and multidrug-resistant (EPG85-257RDB/tetR/YB-1) gastric carcinoma cells in which the expression of YB-1 can be inhibited by tetracycline-dependent activation of the RNA interference (RNAi) pathway, was analyzed by microarray technology. By this approach, various potentially regulated genes encoding members of important cellular pathways such as the Jak/STAT, VEGF and the MAP-kinase signaling pathways were identified. Independent validation of these findings by quantitative real-time reverse transcriptase polymerase chain reaction and Western blot did not confirm these regulatory effects. In conclusion, the findings suggest that YB-1 is not directly involved in the regulation of mRNA expression in drug-sensitive or drug-resistant gastric carcinoma cells.

  2. Rheology-sensitive response of zeolite-supported anti-inflammatory drug systems.

    PubMed

    Pasquino, R; Di Domenico, M; Izzo, F; Gaudino, D; Vanzanella, V; Grizzuti, N; de Gennaro, B

    2016-10-01

    Drug release from inorganic supports is a challenge for the scientific community for various reasons, related to the low costs of the systems and the possibility of easily regulating the drug release. In the present work, surface-modified zeolite particles are used as carriers for non steroidal antiflammatory drugs (NSAIDs). The release of the drug has been studied in a solution that simulates the intestinal fluid as well as in a gel-like system, based on a surfactant and a binding salt. In the solution case, the quantity of drug released has been tracked via spectrophotometric assay. Release in the gel has been monitored by rheological methods. The molecular conformation of the NSAIDs is fundamental for the interaction with the zeolite surface, whose modified surface has a strong binding energy. It has been proven that the main mechanism for the drug release is anion exchange. It has been found that the NSAIDs, used in their sodic form, can act as binding salts by themselves in the gel-like system, thus changing the viscoelastic response of the overall solution. Drug release kinetics in the solution compare quantitatively well with the released drug in the gel-like fluid, as measured by rheometry.

  3. Development of a glucose-sensitive drug delivery device: Microencapsulated liposomes and poly(2-ethylacrylic acid)

    NASA Astrophysics Data System (ADS)

    Kanokpanont, Sorada

    The current study is the development a self-regulated, glucose responsive drug delivery system, using dioleoylphosphatidylcholine (DOPC) liposomes, a pH sensitive polymer, poly (2-ethylacrylic acid)(PEAA), and the feed back reaction of glucose with glucose oxidase enzyme (GO). The thesis investigates the use of PEAR and liposomes to work inside a microcapsule in response to the glucose level of the environment, by following the release of fluorescence probes, 8-aminonapthalene-1,3,6-trisulfonic acid, disodium salt/p-xylene-bis-pyridimuim bromide (ANTS/DPX) and a model protein, myoglobin. The continuing studies of PEAR and liposome interaction indicated an evidence of the previous hypothesis of two-mode release at different pHs. Differential scanning calorimetric studies of DOPC and PEAA complexes revealed the possibility of polymer adsorption to the liposomes in the pH range 5.5--7.0 and insertion in the liposome bilayer at pH < 5.2. The rate and extent of ANTS/DPX release from un-encapsulated liposomes were found to be affected by pH, PEAR concentration, presence of cholesterol in the liposomes, Ca 2+, and the concentration of sodium alginate. We have also shown possibilities of anchoring PEAR on to liposome by covalent conjugation although this led to inactivation of the polymer. It is also possible to entrap small molecular weight PEAA in liposomes. The evidence of the pH-induced protein release by the interaction of PEAA and liposomes was first demonstrated in this thesis. Kinetic parameters of GO were estimated to use as a basis for determination optimal concentration in the capsules. The pH reduction inside the capsule due to GO reaction showed positive results for the use of GO in a non-buffered system. The procedure of liquid-core alginate capsules was modified to facilitate the pH-responsive release of ANTS/DPX and myoglobin. The capsules responded to high blood glucose concentration by releasing myoglobin within 30 minutes. Although more studies are

  4. Four-Month Moxifloxacin-Based Regimens for Drug-Sensitive Tuberculosis

    PubMed Central

    Gillespie, Stephen H.; Crook, Angela M.; McHugh, Timothy D.; Mendel, Carl M.; Meredith, Sarah K.; Murray, Stephen R.; Pappas, Frances; Phillips, Patrick P.J.; Nunn, Andrew J.

    2014-01-01

    BACKGROUND Early-phase and preclinical studies suggest that moxifloxacin-containing regimens could allow for effective 4-month treatment of uncomplicated, smear-positive pulmonary tuberculosis. METHODS We conducted a randomized, double-blind, placebo-controlled, phase 3 trial to test the noninferiority of two moxifloxacin-containing regimens as compared with a control regimen. One group of patients received isoniazid, rifampin, pyrazinamide, and ethambutol for 8 weeks, followed by 18 weeks of isoniazid and rifampin (control group). In the second group, we replaced ethambutol with moxifloxacin for 17 weeks, followed by 9 weeks of placebo (isoniazid group), and in the third group, we replaced isoniazid with moxifloxacin for 17 weeks, followed by 9 weeks of placebo (ethambutol group). The primary end point was treatment failure or relapse within 18 months after randomization. RESULTS Of the 1931 patients who underwent randomization, in the per-protocol analysis, a favorable outcome was reported in fewer patients in the isoniazid group (85%) and the ethambutol group (80%) than in the control group (92%), for a difference favoring the control group of 6.1 percentage points (97.5% confidence interval [CI], 1.7 to 10.5) versus the isoniazid group and 11.4 percentage points (97.5% CI, 6.7 to 16.1) versus the ethambutol group. Results were consistent in the modified intention-to-treat analysis and all sensitivity analyses. The hazard ratios for the time to culture negativity in both solid and liquid mediums for the isoniazid and ethambutol groups, as compared with the control group, ranged from 1.17 to 1.25, indicating a shorter duration, with the lower bounds of the 95% confidence intervals exceeding 1.00 in all cases. There was no significant difference in the incidence of grade 3 or 4 adverse events, with events reported in 127 patients (19%) in the isoniazid group, 111 (17%) in the ethambutol group, and 123 (19%) in the control group. CONCLUSIONS The two moxifloxacin

  5. Development of Novel Polymeric Materials for Gene Therapy and pH-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, and Analysis

    SciTech Connect

    Anderson, Brian Curtis

    2002-01-01

    The underlying theme of this thesis is the use of polymeric materials in bioapplications. Chapters 2-5 either develop a fundamental understanding of current materials used for bioapplications or establish protocols and procedures used in characterizing and synthesizing novel materials. In chapters 6 and 7 these principles and procedures are applied to the development of materials to be used for gene therapy and drug delivery. Chapter one is an introduction to the ideas that will be necessary to understand the subsequent chapters, as well as a literature review of these topics. Chapter two is a paper that has been published in the ''Journal of Controlled Release'' that examines the mechanism of drug release from a polymer gel, as well as experimental design suggestions for the evaluation of water soluble drug delivery systems. Chapter three is a paper that has been published in the ''Journal of Pharmaceutical Sciences'' that discusses the effect ionic salts have on properties of the polymer systems examined in chapter two. Chapter four is a paper published in the Materials Research Society Fall 2000 Symposium Series dealing with the design and synthesis of a pH-sensitive polymeric drug delivery device. Chapter five is a paper that has been published in the journal ''Biomaterials'' proposing a novel polymer/metal composite for use as a biomaterial in hip arthroplasty surgery. Chapter six is a paper that will appear in an upcoming volume of the Journal ''Biomaterials'' dealing with the synthesis of a novel water soluble cationic polymer with possible applications in non-viral gene therapy. Chapter seven is a paper that has been submitted to ''Macromolecules'' discussing several novel block copolymers based on poly(ethylene glycol) and poly(diethylamino ethyl methacrylate) that possess both pH-sensitive and temperature sensitive properties. Chapter eight contains a summary of the research contained in chapters 2-7 and proposes future research for the gene therapy and

  6. The butyrylcholinesterase knockout mouse a research tool in the study of drug sensitivity, bio-distribution, obesity and Alzheimer's disease.

    PubMed

    Duysen, Ellen G; Li, Bin; Lockridge, Oksana

    2009-05-01

    Butyrylcholinesterase (BChE) mutations common in the human population may result in complete or partial BChE deficiency, making the BChE knockout (KO) mouse a model for human deficiencies. The BChE KO mouse cannot tolerate standard doses of the muscle relaxant succinylcholine or the Alzheimer's disease drugs huperzine A and donepezil. It is resistant to the asthma drug bambuterol. The importance of BChE in detoxication of cocaine has been demonstrated by hepatotoxicity and cardiotoxicity in cocaine-challenged BChE KO mice. The BChE KO mouse becomes obese on a high-fat diet, suggesting a role for BChE in fat metabolism. BChE serves as a backup for acetylcholinesterase by hydrolyzing the neurotransmitter acetylcholine in acetylcholinesterase knockout mice. Imaging studies show that BChE injected intrathecally crosses the blood-brain barrier. Mice, but not humans, have carboxylesterase in their blood. Carboxylesterase obscures the role of BChE in detoxication of organophosphorus pesticides. Future studies will make a double knockout that has neither BChE nor carboxylesterase. The double knockout is expected to be unusually sensitive to the toxicity of organophosphorus pesticides. Knowledge of drug sensitivities in the mouse model of human BChE deficiency will aid in understanding adverse drug effects in humans.

  7. A simple, rapid, and sensitive system for the evaluation of anti-viral drugs in rats

    SciTech Connect

    Li, Xiaoguang; Qian, Hua; Miyamoto, Fusako; Kawaji, Kumi; Hattori, Toshio; Watanabe, Kentaro; Oishi, Shinya; Fujii, Nobutaka; and others

    2012-07-27

    Highlights: Black-Right-Pointing-Pointer We established a novel, simple and rapid in vivo system for evaluation of anti-HIV-1 drugs with rats. Black-Right-Pointing-Pointer The system may be applicable for other antiviral drugs, and/or useful for initial screening in vivo. Black-Right-Pointing-Pointer In this system, TRI-1144 displayed the most potent anti-HIV-1 activity in vivo. -- Abstract: The lack of small animal models for the evaluation of anti-human immunodeficiency virus type 1 (HIV-1) agents hampers drug development. Here, we describe the establishment of a simple and rapid evaluation system in a rat model without animal infection facilities. After intraperitoneal administration of test drugs to rats, antiviral activity in the sera was examined by the MAGI assay. Recently developed inhibitors for HIV-1 entry, two CXCR4 antagonists, TF14016 and FC131, and four fusion inhibitors, T-20, T-20EK, SC29EK, and TRI-1144, were evaluated using HIV-1{sub IIIB} and HIV-1{sub BaL} as representative CXCR4- and CCR5-tropic HIV-1 strains, respectively. CXCR4 antagonists were shown to only possess anti-HIV-1{sub IIIB} activity, whereas fusion inhibitors showed both anti-HIV-1{sub IIIB} and anti-HIV-1{sub BaL} activities in rat sera. These results indicate that test drugs were successfully processed into the rat sera and could be detected by the MAGI assay. In this system, TRI-1144 showed the most potent and sustained antiviral activity. Sera from animals not administered drugs showed substantial anti-HIV-1 activity, indicating that relatively high dose or activity of the test drugs might be needed. In conclusion, the novel rat system established here, 'phenotypic drug evaluation', may be applicable for the evaluation of various antiviral drugs in vivo.

  8. The degradation and biocompatibility of pH-sensitive biodegradable polyurethanes for intracellular multifunctional antitumor drug delivery.

    PubMed

    Zhou, Lijuan; Liang, Dong; He, Xueling; Li, Jiehua; Tan, Hong; Li, Jianshu; Fu, Qiang; Gu, Qun

    2012-03-01

    To obtain controllable stepwise biodegradable polymer for multifunctional antitumor drug carriers, pH-sensitive biodegradable polyurethanes were firstly synthesized using poly(ε-caprolactone) (PCL) and pH-sensitive poly(ε-caprolactone)-hydrazone-poly(ethylene glycol)-hydrazone-poly(ε-caprolactone) macrodiol (PCLH) as soft segment; l-lysine ethyl ester diisocyanate (LDI), l-lysine derivative tripeptide and 1,4-butandiol (BDO) as hard segment; and hydrazone-linked methoxyl-poly(ethylene glycol)(m-PEG-Hyd) as end-capper. Then, an extensive degradation process of the prepared pH-sensitive polyurethanes was investigated in vitro with proton nuclear magnetic resonance spectra ((1)H NMR), gel permeation chromatograph (GPC), scanning electron microscopy (SEM), and weight loss. It was found that the degradation of these polyurethanes occurred via the random hydrolytic ester cleavage along the PCL segments close to PEG segments in enzymatic solutions while the hydrazone bond in the polymer chain was more easily cleaved in acidic media, which was accelerated with decreasing pH value. Furthermore, the biocompatibility in vivo was evaluated in an intramuscular implantation model on Sprague-Dawley rats, using SEM and light microscopy. The result showed that the prepared polyurethanes can be easily degraded and the degradation products do not induce any adverse response from surrounding muscle tissues. Our work suggests that the prepared pH-sensitive polyurethanes could be promising materials as controllable biodegradable and non-cyctotoxic multifunctional carriers for active intracellular drug delivery.

  9. Sensitivity in vitro of Plasmodium falciparum to three currently used antimalarial drugs on the western border of Thailand.

    PubMed

    Fèvre, E M; Barnish, G; Yamokgul, P; Rooney, W

    1999-01-01

    The sensitivity in vitro of Plasmodium falciparum to mefloquine, quinine and artemisinin was assessed in an area of multi-drug resistance on the Thai-Myanmar border, using the World Health Organization's microtest, based on schizont maturation inhibition. Participating individuals were exclusively those who had contracted their infections within Myanmar. A total of 34 successful tests were carried out for mefloquine and quinine, showing a marked decrease in sensitivity compared to previously published results. Ten artemisinin tests were successful, with many failures due to the poor storage stability of the test plates. The implications of the shelf-life of the artemisinin plates is discussed. These results contribute to setting a base line of sensitivity to artemisinin in vitro.

  10. Graphene oxide-enhanced sol-gel transition sensitivity and drug release performance of an amphiphilic copolymer-based nanocomposite

    PubMed Central

    Hu, Huawen; Wang, Xiaowen; Lee, Ka I; Ma, Kaikai; Hu, Hong; Xin, John H.

    2016-01-01

    We report the fabrication of a highly sensitive amphiphilic copolymer-based nanocomposite incorporating with graphene oxide (GO), which exhibited a low-intensity UV light-triggered sol-gel transition. Non-cytotoxicity was observed for the composite gels after the GO incorporation. Of particular interest were the microchannels that were formed spontaneously within the GO-incorporated UV-gel, which expedited sustained drug release. Therefore, the present highly UV-sensitive, non-cytotoxic amphiphilic copolymer-based composites is expected to provide enhanced photothermal therapy and chemotherapy by means of GO’s unique photothermal properties, as well as through efficient passive targeting resulting from the sol-gel transition characteristic of the copolymer-based system with improved sensitivity, which thus promises the enhanced treatment of patients with cancer and other diseases. PMID:27539298

  11. Graphene oxide-enhanced sol-gel transition sensitivity and drug release performance of an amphiphilic copolymer-based nanocomposite

    NASA Astrophysics Data System (ADS)

    Hu, Huawen; Wang, Xiaowen; Lee, Ka I.; Ma, Kaikai; Hu, Hong; Xin, John H.

    2016-08-01

    We report the fabrication of a highly sensitive amphiphilic copolymer-based nanocomposite incorporating with graphene oxide (GO), which exhibited a low-intensity UV light-triggered sol-gel transition. Non-cytotoxicity was observed for the composite gels after the GO incorporation. Of particular interest were the microchannels that were formed spontaneously within the GO-incorporated UV-gel, which expedited sustained drug release. Therefore, the present highly UV-sensitive, non-cytotoxic amphiphilic copolymer-based composites is expected to provide enhanced photothermal therapy and chemotherapy by means of GO’s unique photothermal properties, as well as through efficient passive targeting resulting from the sol-gel transition characteristic of the copolymer-based system with improved sensitivity, which thus promises the enhanced treatment of patients with cancer and other diseases.

  12. Anticancer drug detection using a highly sensitive molecularly imprinted electrochemical sensor based on an electropolymerized microporous metal organic framework.

    PubMed

    Florea, Anca; Guo, ZhenZhong; Cristea, Cecilia; Bessueille, François; Vocanson, Francis; Goutaland, François; Dzyadevych, Sergiy; Săndulescu, Robert; Jaffrezic-Renault, Nicole

    2015-06-01

    A simple and highly sensitive approach for the detection of the anti-neoplastic drug gemcitabine is presented, based on a one-step electropolymerized molecularly imprinted microporous-metal-organic-framework. The sensitive layer was prepared by electropolymerization of the aniline moieties of p-aminothiophenol- gold nanoparticles on the surface of gold electrodes tethered with p-aminothiophenol, in the presence of gemcitabine as a template molecule. Experimental parameters that control the performance of the sensor were investigated and optimized. Under optimal conditions a calibration curve was obtained in the linear range from 3.8 fM to 38 nM with a limit of detection of 3 fM. The obtained imprinted sensor has the advantages of easy manufacture, high sensitivity and selectivity and good reproducibility. Furthermore the feasibility of the proposed technique has been investigated on spiked serum samples and infusion solution containing gemcitabine.

  13. Preparation and release of model drugs from thermally sensitive poly(N-isopropylacrylamide) based macrospheres.

    PubMed

    Lewis, G; Coughlan, D C; Lane, M E; Corrigan, O I

    2006-09-01

    Emulsion polymerization was employed to prepare poly(N-isopropylacrylamide) hydrogel spheres, which exhibited an LCST of 32 degrees C. The hydrogels were loaded with model drugs (benzoic acid (BA), sodium benzoate and diltiazem HCl (DHCl)) and release investigated at 25 degrees C and 37 degrees C. The temperature at which gel formation occurred was vital for successful hydrogel preparation, macrosphere formation not occurring when the temperature was close to the LCST. Sphere size increased on decreasing the stirring rate and on slowing the rate of addition of the aqueous phase. Pulsatile delivery was investigated using BA and DHCl. For both compounds a pulse was observed with a change in temperature. Pulsed release of the smaller model drug of lowest solubility, BA, was more successful. Drug release from hydrogel spheres was, therefore, found to be dependent on the physicochemical properties of the drugs, with pulsatile release of low molecular weight compounds, by temperature cycling, difficult to control.

  14. Monitoring drug efficacy against gastrointestinal nematodes when faecal egg counts are low: do the analytic sensitivity and the formula matter?

    PubMed

    Levecke, Bruno; Rinaldi, Laura; Charlier, Johannes; Maurelli, Maria Paola; Morgoglione, Maria Elena; Vercruysse, Jozef; Cringoli, Giuseppe

    2011-09-01

    The faecal egg count reduction test (FECR) is the recommended technique to monitor anthelmintic drug efficacy in livestock. However, results are often inconclusive due to the low analytic sensitivity of the diagnostic technique or the conflict in results from FECR formulae. A novel experimental set-up was, therefore, used to compare the impact of analytic sensitivity and formulae on FECR results. Four McMaster techniques (analytic sensitivities 50, 33.3, 15 and 10) and a FLOTAC technique (analytic sensitivity ~ 1) were used on faecal samples of 30 calves with a FEC of less than 200 eggs per gram. True drug efficacies of 70%, 80% and 90% were experimentally mimicked by comparing FEC before and after dilution (3:10, 2:10 and 1:10, respectively). The FECR was summarized using group (FECR(1)) and individual (FECR(2)) based formulae. There was a significant increase in precision of FECR when the analytic sensitivity increased (p < 0.0001). The precision also depended on the formula used, FECR(1) (p < 0.05) resulting in more precise FECR compared to FECR(2). The accuracy of the FECR differed marginally between the two formulae (p = 0.06), FECR(1) being more accurate. In conclusion, the present study describes a novel methodology to compare techniques for the precision and the accuracy of their FECR results. The results underscored that techniques with high analytic sensitivity will improve the interpretation of FECR in animal populations where baseline FEC are low. They also point out that the precision of individual-based formulae is affected by the analytic sensitivity.

  15. Synthesis of a novel thermo/pH sensitive nanogel based on salep modified graphene oxide for drug release.

    PubMed

    Bardajee, Ghasem Rezanejade; Hooshyar, Zari; Farsi, Maryam; Mobini, Akram; Sang, Golnaz

    2017-03-01

    Nanogels (NGs) are three-dimensional water soluble cross-linked hydrogel materials in the nanoscale size range with a high loading capacity for guest molecules and act as drug carrier systems. In the present work, a new type of thermo/pH sensitive NG comprising salep modified graphene oxide (SMGO) with branched N-isopropylacrylamide (NIPAM) and acrylic acid (AA) was prepared. The SMGO/P(NIPAM-co-AA) NGs exhibited nanoporous structure and spherical particles with diameters about 82nm as characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The samples were also characterized by Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA) to further confirm about the formation of NGs. Doxorubicin (DOX) loaded SMGO/P(NIPAM-co-AA) NGs showed thermo/pH dependent releasing behavior: slow drug release at neutral pH and lower temperature but increased significantly in acidic pH and higher temperature, without any burst release. In addition, the NGs exhibited no effect on the cell viability in the tested concentration range up to 410μg/mL and drug release systems enhanced toxicity to HeLa cells when compared to the equivalent dose of the free drug. Overall, our results put forth NGs as potential candidates in the development of a new nanocarrier for anti-cancer drug delivery.

  16. Increased sensitivity to anticancer drugs and decreased inflammatory response in mice lacking the multidrug resistance-associated protein.

    PubMed

    Wijnholds, J; Evers, R; van Leusden, M R; Mol, C A; Zaman, G J; Mayer, U; Beijnen, J H; van der Valk, M; Krimpenfort, P; Borst, P

    1997-11-01

    The multidrug resistance-associated protein (MRP) mediates the cellular excretion of many drugs, glutathione S-conjugates (GS-X) of lipophilic xenobiotics and endogenous cysteinyl leukotrienes. Increased MRP levels in tumor cells can cause multidrug resistance (MDR) by decreasing the intracellular drug concentration. The physiological role or roles of MRP remain ill-defined, however. We have generated MRP-deficient mice by using embryonic stem cell technology. Mice homozygous for the mrp mutant allele, mrp-/-, are viable and fertile, but their response to an inflammatory stimulus is impaired. We attribute this defect to a decreased secretion of leukotriene C4 (LTC4) from leukotriene-synthesizing cells. Moreover, the mrp-/- mice are hypersensitive to the anticancer drug etoposide. The phenotype of mrp-/- mice is consistent with a role for MRP as the main LTC4-exporter in leukotriene-synthesizing cells, and as an important drug exporter in drug-sensitive cells. Our results suggest that this ubiquitous GS-X pump is dispensable in mice, making treatment of MDR with MRP-specific reversal agents potentially feasible.

  17. Propargyl-Linked Antifolates Are Potent Inhibitors of Drug-Sensitive and Drug-Resistant Mycobacterium tuberculosis

    PubMed Central

    Hajian, Behnoush; Keshipeddy, Santosh; Shoen, Carolyn; Krucinska, Jolanta; Cynamon, Michael; Anderson, Amy C.; Wright, Dennis L.

    2016-01-01

    Mycobacterium tuberculosis continues to cause widespread, life-threatening disease. In the last decade, this threat has grown dramatically as multi- and extensively-drug resistant (MDR and XDR) bacteria have spread globally and the number of agents that effectively treat these infections is significantly reduced. We have been developing the propargyl-linked antifolates (PLAs) as potent inhibitors of the essential enzyme dihydrofolate reductase (DHFR) from bacteria and recently found that charged PLAs with partial zwitterionic character showed improved mycobacterial cell permeability. Building on a hypothesis that these PLAs may penetrate the outer membrane of M. tuberculosis and inhibit the essential cytoplasmic DHFR, we screened a group of PLAs for antitubercular activity. In this work, we identified several PLAs as potent inhibitors of the growth of M. tuberculosis with several of the compounds exhibiting minimum inhibition concentrations equal to or less than 1 μg/mL. Furthermore, two of the compounds were very potent inhibitors of MDR and XDR strains. A high resolution crystal structure of one PLA bound to DHFR from M. tuberculosis reveals the interactions of the ligands with the target enzyme. PMID:27580226

  18. Development of Nano-Liposomal Formulations of Epidermal Growth Factor Receptor Inhibitors and their Pharmacological Interactions on Drug-Sensitive and Drug-Resistant Cancer Cell Lines

    NASA Astrophysics Data System (ADS)

    Trummer, Brian J.

    , due to leaky tumor vasculature and the resulting Enhanced Permeability and Retention (EPR) phenomenon. In Chapter 2 we report that both gefitinib and the structurally similar EGFR inhibitor erlotinib display environment-dependent fluorescence properties. Peak excitation was 345 nm, and the emission peak ranged from 365 to 476 nm, depending upon the polarity of the environment and physical state of the drug. The fluorescence was negligible in aqueous solution, but intense in organic solvents or membrane bilayers. The environment-sensitive fluorescence properties of these drugs enabled rapid evaluation of numerous parameters affecting liposomal drug incorporation and performance. Up to 4-6 mol% of gefitinib could be incorporated in the liposome bilayer, based upon hydrophobic interactions with membrane bilayers. In contrast, 40-60 mol% could be loaded into the aqueous core of pre-formed liposomes at high efficiency, using a remote loading procedure. A stable formulation consisting of distearoylphosphatidylcholine: polyethylene glycol-distereoylphosphatidylethanolamine: cholesterol (DSPC:PEGDSPE:Chol, 9:1:5 mol:mol:mol) and containing drug at 50-60 mol% gefitinib (L-GEF) showed minimal leakage in serum-containing medium over 24 h at 37°C, which should be sufficient to improve biodistribution in vivo. Chapter 3 investigated the pharmacological activity of liposome-encapsulated gefitinib, alone and in combination with several prevalent anticancer agents. Experiments with MCF7 breast cancer cell lines demonstrated that liposome encapsulated gefitinib formulation (L-GEF) had a 2-fold higher IC50 (concentration of drug resulting in half-maximal growth inhibition) than free gefitinib. Lower in vitro potency would be consistent with delayed drug release from the carrier. Therapeutic effects were investigated in combination with the cytotoxic agents paclitaxel and doxorubicin. The drug-resistant MCF7R cell line was 23-fold more resistant to paclitaxel than the parental, drug-sensitive

  19. Delivering instilled hydrophobic drug to the bladder by a cationic nanoparticle and thermo-sensitive hydrogel composite system

    NASA Astrophysics Data System (ADS)

    Men, Ke; Liu, Wei; Li, Lin; Duan, Xingmei; Wang, Pan; Gou, Maling; Wei, Xiawei; Gao, Xiang; Wang, Bilan; Du, Yanan; Huang, Meijuan; Chen, Lijuan; Qian, Zhiyong; Wei, Yuquan

    2012-09-01

    Some bladder disease therapies can benefit from intravesical drug delivery, which involves direct instillation of drug into the bladder via a catheter, to attain high local concentrations of the drug with minimal systemic effects. Deguelin is a potential anticancer agent, however, its poor water solubility and neurotoxicity restrict its clinical application. To address these challenges, we investigated the promising application of deguelin in the intravesical therapy of bladder cancer by designing a novel intravesical drug delivery system for deguelin. It was found that deguelin could efficiently kill bladder cancer cells and inhibit angiogenesis. Intravesically administrated deguelin had better tolerance than systemically applied deguelin. Encapsulation of deguelin in cationic DOTAP and monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) hybrid nanoparticles (DMP) created the deguelin loaded DMP nanoparticles (D/DMP). They had a mean particle size of 35 nm and zeta potential of 21 mV, rendering deguelin completely dispersible in aqueous media. Encapsulation of deguelin in cationic DMP nanoparticles enhanced the anticancer activity of deguelin in vitro. In addition, D/DMP nanoparticles were incorporated into a thermo-sensitive Pluronic F127 hydrogel, forming a novel D/DMP-F system, which remained in a flowing liquid state at lower than 25 °C, but underwent gelation at higher temperatures. The DMP nanoparticles in the F127 hydrogel system (DMP-F) could significantly extend the hydrophobic drug residence time and increase the drug concentration within the bladder. These results suggested that DMP-F was a good intravesical drug delivery system and D/DMP-F may have promising applications in intravesical therapy of bladder cancer.

  20. Neutralizing antibody and anti-retroviral drug sensitivities of HIV-1 isolates resistant to small molecule CCR5 inhibitors

    SciTech Connect

    Pugach, Pavel; Ketas, Thomas J.; Michael, Elizabeth; Moore, John P.

    2008-08-01

    The small molecule CCR5 inhibitors are a new class of drugs for treating infection by human immunodeficiency virus type 1 (HIV-1). They act by binding to the CCR5 co-receptor and preventing its use during HIV-1-cell fusion. Escape mutants can be raised against CCR5 inhibitors in vitro and will arise when these drugs are used clinically. Here, we have assessed the responses of CCR5 inhibitor-resistant viruses to other anti-retroviral drugs that act by different mechanisms, and their sensitivities to neutralizing antibodies (NAbs). The rationale for the latter study is that the resistance pathway for CCR5 inhibitors involves changes in the HIV-1 envelope glycoproteins (Env), which are also targets for NAbs. The escape mutants CC101.19 and D1/85.16 were selected for resistance to AD101 and vicriviroc (VVC), respectively, from the primary R5 HIV-1 isolate CC1/85. Each escape mutant was cross-resistant to other small molecule CCR5 inhibitors (aplaviroc, maraviroc, VVC, AD101 and CMPD 167), but sensitive to protein ligands of CCR5: the modified chemokine PSC-RANTES and the humanized MAb PRO-140. The resistant viruses also retained wild-type sensitivity to the nucleoside reverse transcriptase inhibitor (RTI) zidovudine, the non-nucleoside RTI nevirapine, the protease inhibitor atazanavir and other attachment and fusion inhibitors that act independently of CCR5 (BMS-806, PRO-542 and enfuvirtide). Of note is that the escape mutants were more sensitive than the parental CC1/85 isolate to a subset of neutralizing monoclonal antibodies and to some sera from HIV-1-infected people, implying that sequence changes in Env that confer resistance to CCR5 inhibitors can increase the accessibility of some NAb epitopes. The need to preserve NAb resistance may therefore be a constraint upon how escape from CCR5 inhibitors occurs in vivo.

  1. Neutralizing antibody and anti-retroviral drug sensitivities of HIV-1 isolates resistant to small molecule CCR5 inhibitors

    PubMed Central

    Pugach, Pavel; Ketas, Thomas J.; Michael, Elizabeth; Moore, John P.

    2008-01-01

    The small molecule CCR5 inhibitors are a new class of drugs for treating infection by human immunodeficiency virus type 1 (HIV-1). They act by binding to the CCR5 co-receptor and preventing its use during HIV-1-cell fusion. Escape mutants can be raised against CCR5 inhibitors in vitro and will arise when these drugs are used clinically. Here, we have assessed the responses of CCR5 inhibitor-resistant viruses to other anti-retroviral drugs that act by different mechanisms, and their sensitivities to neutralizing antibodies (NAbs). The rationale for the latter study is that the resistance pathway for CCR5 inhibitors involves changes in the HIV-1 envelope glycoproteins (Env), which are also targets for NAbs. The escape mutants CC101.19 and D1/85.16 were selected for resistance to AD101 and vicriviroc (VVC), respectively, from the primary R5 HIV-1 isolate CC1/85. Each escape mutant was cross resistant to other small molecule CCR5 inhibitors (aplaviroc, maraviroc, VVC, AD101 and CMPD 167), but sensitive to protein ligands of CCR5: the modified chemokine PSC-RANTES and the humanized MAb PRO 140. The resistant viruses also retained wild-type sensitivity to the nucleoside reverse transcriptase inhibitor (RTI) zidovudine, the non-nucleoside RTI nevirapine, the protease inhibitor atazanavir and other attachment and fusion inhibitors that act independently of CCR5 (BMS-806, PRO-542 and enfuvirtide). Of note is that the escape mutants were more sensitive than the parental CC1/85 isolate to a subset of neutralizing monoclonal antibodies and to some sera from HIV-1-infected people, implying that sequence changes in Env that confer resistance to CCR5 inhibitors can increase the accessibility of some NAb epitopes. The need to preserve NAb resistance may therefore be a constraint upon how escape from CCR5 inhibitors occurs in vivo. PMID:18519143

  2. Machine learning plus optical flow: a simple and sensitive method to detect cardioactive drugs.

    PubMed

    Lee, Eugene K; Kurokawa, Yosuke K; Tu, Robin; George, Steven C; Khine, Michelle

    2015-07-03

    Current preclinical screening methods do not adequately detect cardiotoxicity. Using human induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs), more physiologically relevant preclinical or patient-specific screening to detect potential cardiotoxic effects of drug candidates may be possible. However, one of the persistent challenges for developing a high-throughput drug screening platform using iPS-CMs is the need to develop a simple and reliable method to measure key electrophysiological and contractile parameters. To address this need, we have developed a platform that combines machine learning paired with brightfield optical flow as a simple and robust tool that can automate the detection of cardiomyocyte drug effects. Using three cardioactive drugs of different mechanisms, including those with primarily electrophysiological effects, we demonstrate the general applicability of this screening method to detect subtle changes in cardiomyocyte contraction. Requiring only brightfield images of cardiomyocyte contractions, we detect changes in cardiomyocyte contraction comparable to - and even superior to - fluorescence readouts. This automated method serves as a widely applicable screening tool to characterize the effects of drugs on cardiomyocyte function.

  3. Digital morphonuclear analyses of sensitive versus resistant neoplastic cells to vinca-alkaloid, alkylating, and intercalating drugs.

    PubMed

    Pauwels, O; Kiss, R

    1991-01-01

    We tested 12 resistant cell lines in vitro in order to evaluate common morphonuclear characteristics induced by various cytotoxic drugs on cell lines of different origins. We used the MXT mouse mammary cancer and the neoplastic J82 and T24 human bladder cell lines, whose variants are either sensitive or resistant to a vinca alkaloid derivative (Navelbine, NVB), to an investigational alkylating agent (PE1001), and to Adriamycin (ADR). We tested cell population variants resistant to NVB + PE1001 + ADR. The level of chemoresistance was evaluated by a colorimetric assay assessing the 50% concentration-induced inhibition of cellular growth (IC50) brought about by each drug on the growth of each cell variant under study. We show that resistant neoplastic cell nuclei present common morphonuclear characteristics, independent of cell origin (neoplastic mouse mammary versus human bladder cells) and the drug used (vinca alkaloid, alkylating, and intercalating derivatives). Our results further indicate that the phenotype of resistant versus sensitive cells corresponds to cell nuclei populations with smaller nuclei and less nuclear DNA content and, as a consequence, a chromatin texture showing large pale areas with some hyperchromatic clumps.

  4. Ultrasound-mediated intracellular drug delivery using microbubbles and temperature-sensitive liposomes.

    PubMed

    Yudina, A; de Smet, M; Lepetit-Coiffé, M; Langereis, S; Van Ruijssevelt, L; Smirnov, P; Bouchaud, V; Voisin, P; Grüll, H; Moonen, C T W

    2011-11-07

    A novel two-step protocol for intracellular drug delivery has been evaluated in vitro. As a first step TO-PRO-3 (a cell-impermeable dye that displays a strong fluorescence enhancement upon binding to nucleic acids) encapsulated in thermosensitive liposomes was released after heating to 42°C. A second step consisted of ultrasound-mediated local permeabilization of cell membrane allowing TO-PRO-3 internalization observable as nuclear staining. Only the combination of two consecutive steps - heating and sonication in the presence of SonoVue microbubbles led to the model drug TO-PRO-3 release from the thermosensitive liposomes and its intracellular uptake. This protocol is potentially beneficial for the intracellular delivery of cell impermeable drugs that suffer from rapid clearance and/or degradation in blood and are not intrinsically taken up by cells.

  5. Multifunctional pH-sensitive superparamagnetic iron-oxide nanocomposites for targeted drug delivery and MR imaging.

    PubMed

    Zhu, Lijuan; Wang, Dali; Wei, Xuan; Zhu, Xinyuan; Li, Jianqi; Tu, Chunlai; Su, Yue; Wu, Jieli; Zhu, Bangshang; Yan, Deyue

    2013-08-10

    A multifunctional pH-sensitive superparamagnetic iron-oxide (SPIO) nanocomposite system was developed for simultaneous tumor magnetic resonance imaging (MRI) and therapy. Small-size SPIO nanoparticles were chemically bonded with antitumor drug doxorubicin (DOX) and biocompatible poly(ethylene glycol) (PEG) through pH-sensitive acylhydrazone linkages, resulting in the formation of SPIO nanocomposites with magnetic targeting and pH-sensitive properties. These DOX-conjugated SPIO nanocomposites exhibited not only good stability in aqueous solution but also high saturation magnetizations. Under an acidic environment, the DOX was quickly released from the SPIO nanocomposites due to the cleavage of pH-sensitive acylhydrazone linkages. With the help of magnetic field, the DOX-conjugated SPIO nanocomposites showed high cellular uptake, indicating their magnetic targeting property. Comparing to free DOX, the DOX-conjugated SPIO nanocomposites showed better antitumor effect under magnetic field. At the same time, the relaxivity value of these SPIO nanocomposites was higher than 146s(-1)mM(-1) Fe, leading to ~4 times enhancement compared to that of free SPIO nanoparticles. As a negative contrast agent, these SPIO nanocomposites illustrated high resolution in MRI diagnosis of tumor-bearing mice. All of these results confirm that these pH-sensitive SPIO nanocomposites are promising hybrid materials for synergistic MRI diagnosis and tumor therapy.

  6. Pyrilamine-sensitive proton-coupled organic cation (H(+)/OC) antiporter for brain-specific drug delivery.

    PubMed

    Wang, Xinyi; Qi, Bowen; Su, Huifang; Li, Jianbo; Sun, Xun; He, Qin; Fu, Yao; Zhang, Zhirong

    2017-03-27

    Blood-brain barrier (BBB) represents the greatest challenge that hampers therapeutic molecules entering the brain. Here, we described a novel brain-specific delivery strategy targeting to pyrilamine-sensitive H(+)/OC antiporter to facilitate therapeutic molecules cross the BBB and penetrate into the brain. In this study, four cyclic tertiary amines were selected as the brain-targeting moieties to modify naproxen (NP), a non-steroidal anti-inflammatory drug. The obtained NP conjugates displayed cell uptake efficiencies over 144-fold higher than that of unmodified NP in endothelial cells. The cell uptake process of the conjugates was primarily driven by pyrilamine-sensitive H(+)/OC antiporter in a pH-dependent, Na(+)-independent, and membrane potential-independent pathway, which could be further inhibited by pyrilamine, propranolol, and imipramine. Moreover, the NP conjugates showed significantly higher AUC0-t and Cmax in the brain compared with unmodified NP, and significantly higher accumulation than NP in the in situ brain perfusion study. Also, the conjugates showed superior neuroprotective effect in vitro and in vivo. Thus, the chemical modification of therapeutics with a cyclic tertiary amine moiety represents a promising and efficient strategy for brain-specific drug delivery via pyrilamine-sensitive H(+)/OC antiporter.

  7. Investigation of thermo-sensitive amphiphilic micelles as drug carriers for chemotherapy in cholangiocarcinoma in vitro and in vivo.

    PubMed

    Wang, Xuefeng; Li, Songgang; Wan, Ziwei; Quan, Zhiwei; Tan, Qinggang

    2014-03-10

    Cholangiocarcinoma is an epithelial cancer of the bile ducts with poor prognosis and, in recent years, a rapidly increasing incidence. In this study, nano-sized thermo-sensitive micelles were investigated as drug carriers to improve chemotherapy in cholangiocarcinoma. Thermo-sensitive amphiphilic block copolymer, P-(N,N-isopropylacrylamide-co-N-hydroxymethylacrylamide)-b-caprolactone [P-(NIPAAm-co-NHMAAm)-b-PCL] with lower critical solution temperature (LCST) at about 38°C was synthesized. Doxorubicin (DOX)-loaded micelles were prepared by dialysis method. The micelles exhibited a sustained and temperature-dependent DOX release. Toxicity of the blank micelles for human cholangiocarcinoma (QBC939) cells was minimal both in vitro and in vivo. In contrast, the DOX-loaded micelles effectively inhibited proliferation and induced apoptosis of QBC939 cells in vitro (p<0.05) and inhibited tumor growth in nude mice by 21.49%. These results indicated that thermo-sensitive amphiphilic micelles are a promising and effective drug carrier, and show potential for improving chemotherapy for cholangiocarcinoma.

  8. Hedgehog signaling regulates drug sensitivity by targeting ABC transporters ABCB1 and ABCG2 in epithelial ovarian cancer.

    PubMed

    Chen, Yi; Bieber, Marcia M; Teng, Nelson N H

    2014-08-01

    A major challenge of successful chemotherapy in ovarian cancer is overcoming intrinsic or acquired multi-drug resistance caused by active drug efflux mediated by ATP-binding cassette (ABC) transporters. Regulation of these transporters in ovarian cancer is poorly understood. We have found that abnormal expression of the hedgehog (Hh) signaling pathway transcription factor Gli1 is involved in the regulation of ABC transporters ABCB1 and ABCG2 in ovarian cancer. Hh is a known regulator of cancer cell proliferation and differentiation in several other types of invasive and metastatic malignancies. Our work has demonstrated that Gli1 is abnormally activated in a portion of ovarian cancers. Inhibition of Gli1 expression decreases ABCB1 and ABCG2 gene expression levels and enhances the response of ovarian cancer cells to certain chemotherapeutic drugs. The underlying mechanism is a direct association of Gli1 with a specific consensus sequence located in the promoter region of ABCB1 and ABCG2 genes. This study provides new understanding of ABC gene regulation by Hh signaling pathway, which may lead to the identification of new markers to detect and to anticipate ovarian cancer chemotherapy drug sensitivity.

  9. Simple and sensitive high performance liquid chromatography method with fluorescence detection for therapeutic drug monitoring of topiramate.

    PubMed

    Milosheska, Daniela; Vovk, Tomaž; Grabnar, Iztok; Roškar, Robert

    2015-01-01

    A simple, sensitive, accurate, precise and inexpensive HPLC method with fluorescence detection, suitable for routine therapeutic drug monitoring (TDM) of an antiepileptic drug topiramate, was developed and validated. The determination of plasma topiramate concentration was carried out after precolumn derivatization, using 4-chloro-7-nitrobenzofurazan as a fluorescent labeling agent and bendroflumethiazide as an internal standard. The standard calibration curve was linear over the concentration range of 0.01-24 μg/mL (r² > 0.9998). The intra- and inter-day accuracies expressed as bias were from 1.4 to 9.9% and from 1.9 to 10.2%, respectively. The intra- and inter-day precisions were below 7.9% and 2.7%, respectively. The validated method was applied for the measurement of plasma topiramate concentrations in patients with epilepsy. The reported method is appropriate for TDM of topiramate as well as for pharmacokinetic and bioequivalence studies.

  10. Suppression of gastric acid increases the risk of developing Immunoglobulin E-mediated drug hypersensitivity: human diclofenac sensitization and a murine sensitization model

    PubMed Central

    Riemer, A. B.; Gruber, S.; Pali-Schöll, I.; Kinaciyan, T.; Untersmayr, E.; Jensen-Jarolim, E.

    2010-01-01

    Summary Background Hypersensitivity reactions towards non-steroidal anti-inflammatory drugs (NSAID) are common, although true allergies are detectable only in a subgroup of patients. The current study was prompted by a case observation, where a patient experienced generalized urticaria following his second course of diclofenac and proton pump inhibitor medication, and was found to have diclofenac-specific IgE. During recent years, our group has been investigating the importance of gastric digestion in the development of food allergies, demonstrating anti-acid medication as a risk factor for sensitization against food proteins. Objective Here, we aimed to investigate whether the mechanism of food allergy induction described can also be causative in NSAID allergy, using diclofenac as a paradigm. Methods We subjected BALB/c mice to several oral immunization regimens modelled after the patient’s medication intake. Diclofenac was applied with or without gastric acid suppression, in various doses, alone or covalently coupled to albumin, a protein abundant in gastric juices. Immune responses were assessed on the antibody level, and functionally examined by in vitro and in vivo crosslinking assays. Results Only mice receiving albumin-coupled diclofenac under gastric acid suppression developed anti-diclofenac IgG1 and IgE, whereas no immune responses were induced by the drug alone or without gastric acid suppression. Antibody induction was dose dependent with the group receiving the higher dose of the drug showing sustained anti-diclofenac titres. The antibodies induced triggered basophil degranulation in vitro and positive skin tests in vivo. Conclusion Gastric acid suppression was found to be a causative mechanism in the induction of IgE-mediated diclofenac allergy. PMID:19817752

  11. Nationwide survey of the development of drug-resistant pathogens in the pediatric field in 2007 and 2010: drug sensitivity of Streptococcus pneumoniae in Japan (second report).

    PubMed

    Tajima, Takeshi; Sato, Yoshitake; Toyonaga, Yoshikiyo; Hanaki, Hideaki; Sunakawa, Keisuke

    2013-06-01

    We previously conducted nationwide surveillance of Streptococcus pneumoniae in 2000-2001 (period 1) and 2004 (period 2) and reported the findings. Subsequent surveillance surveys conducted in 2007 (period 3) and 2010 (period 4) are now reported. Bacterial strains were clinically isolated from children with meningitis, sepsis, and respiratory tract infections at 27 hospitals participating in the Drug-Resistant Pathogen Surveillance Group in Pediatric Infectious Disease. Twenty-one drugs were investigated for 283 isolated strains in period 3, and 24 drugs were investigated for 459 strains in period 4. In period 3, 43.8 % of strains were penicillin-susceptible S. pneumoniae (PSSP), 52.3 % were penicillin-intermediate S. pneumoniae (PISP), and 3.9 % were penicillin-resistant S. pneumoniae (PRSP). In period 4, the percentages were PSSP 23.1 %, PISP 49.9 %, and PRSP 27.0 %. The resistance rates were 56.2 % and 76.9 %, respectively. Drug sensitivity was best with panipenem, at a minimum inhibitory concentration (MIC)90 ≤0.063 μg/ml in period 3, and with tebipenem (MIC90 ≤ 0.063 μg/ml) in period 4. Patients' background factors related to increased bacterial resistance were investigated, and significant differences were found depending on whether a child had siblings (P = 0.0056) or was a daycare center attendee (P = 0.0195) in period 3, and age category (P = 0.0256) in period 4. No factors were common to both periods 3 and 4. Pneumococcus is a major causative organism of pediatric infectious disease, and we plan to continue conducting surveillance and providing information in the future.

  12. Intermittent Preventive Treatment with Dihydroartemisinin-Piperaquine in Ugandan Schoolchildren Selects for Plasmodium falciparum Transporter Polymorphisms That Modify Drug Sensitivity

    PubMed Central

    Conrad, Melissa D.; Legac, Jennifer; Tukwasibwe, Stephen; Tumwebaze, Patrick; Wandera, Bonnie; Brooker, Simon J.; Staedke, Sarah G.; Kamya, Moses R.; Nsobya, Sam L.; Dorsey, Grant; Rosenthal, Philip J.

    2016-01-01

    Dihydroartemisinin-piperaquine (DP) offers prolonged protection against malaria, but its impact on Plasmodium falciparum drug sensitivity is uncertain. In a trial of intermittent preventive treatment in schoolchildren in Tororo, Uganda, in 2011 to 2012, monthly DP for 1 year decreased the incidence of malaria by 96% compared to placebo; DP once per school term offered protection primarily during the first month after therapy. To assess the impact of DP on selection of drug resistance, we compared the prevalence of key polymorphisms in isolates that emerged at different intervals after treatment with DP. Blood obtained monthly and at each episode of fever was assessed for P. falciparum parasitemia by microscopy. Samples from 160 symptomatic and 650 asymptomatic episodes of parasitemia were assessed at 4 loci (N86Y, Y184F, and D1246Y in pfmdr1 and K76T in pfcrt) that modulate sensitivity to aminoquinoline antimalarials, utilizing a ligase detection reaction-fluorescent microsphere assay. For pfmdr1 N86Y and pfcrt K76T, but not the other studied polymorphisms, the prevalences of mutant genotypes were significantly greater in children who had received DP within the past 30 days than in those not treated within 60 days (86Y, 18.0% versus 8.3% [P = 0.03]; 76T, 96.0% versus 86.1% [P = 0.05]), suggesting selective pressure of DP. Full sequencing of pfcrt in a subset of samples did not identify additional polymorphisms selected by DP. In summary, parasites that emerged soon after treatment with DP were more likely than parasites not under drug pressure to harbor pfmdr1 and pfcrt polymorphisms associated with decreased sensitivity to aminoquinoline antimalarials. (This study has been registered at ClinicalTrials.gov under no. NCT01231880.) PMID:27401569

  13. Cell proliferation and drug sensitivity of human glioblastoma cells are altered by the stable modulation of cytosolic 5'-nucleotidase II.

    PubMed

    Cividini, F; Cros-Perrial, E; Pesi, R; Machon, C; Allegrini, S; Camici, M; Dumontet, C; Jordheim, L P; Tozzi, M G

    2015-08-01

    Cytosolic 5'-nucleotidase II (cN-II) has been reported to be involved in cell survival, nucleotide metabolism and in the cellular response to anticancer drugs. With the aim to further evaluate the role of this enzyme in cell biology, we stably modulated its expression the human glioblastoma cell ADF in which the transient inhibition of cN-II has been shown to induce cell death. Stable cell lines were obtained both with inhibition, obtained with plasmids coding cN-II-targeting short hairpin RNA, and stimulation, obtained with plasmids coding Green Fluorescence Protein (GFP)-fused wild type cN-II or a GFP-fused hyperactive mutant (GFP-cN-II-R367Q), of cN-II expression. Silenced cells displayed a decreased proliferation rate while the over expressing cell lines displayed an increased proliferation rate as evidenced by impedance measurement using the xCELLigence device. The expression of nucleotide metabolism relevant genes was only slightly different between cell lines, suggesting a compensatory mechanism in transfected cells. Cells with decreased cN-II expression were resistant to the nucleoside analog fludarabine confirming the involvement of cN-II in the metabolism of this drug. Finally, we observed sensitivity to cisplatin in cN-II silenced cells and resistance to this same drug in cN-II over-expressing cells indicating an involvement of cN-II in the mechanism of action of platinum derivatives, and most probably in DNA repair. In summary, our findings confirm some previous data on the role of cN-II in the sensitivity of cancer cells to cancer drugs, and suggest its involvement in other cellular phenomenon such as cell proliferation.

  14. Effect of calcium ionophore A23187 on the sensitivity of early sea urchin embryos to cytotoxic neuropharmacological drugs.

    PubMed

    Buznikov, G A; Mileusnić, R; Yurovskaya, M A; Rakić, L J

    1984-01-01

    The ability of cytotoxic neurochemicals (indole and amphetamine derivatives) to block first cleavage division in the embryos of the sea urchin Arbacia lixula abruptly increases when the embryos are incubated in calcium-free seawater and decreases when the external Ca concentration is raised up to 46.4 mM. Sensitivity of the embryos to these drugs decreases also in the presence of the Ca-ionophore A23187. It is suggested that Ca ions are involved in the realization of physiological effects of "prenervous" neurotransmitters whose presence in early sea urchin embryos was shown by us earlier.

  15. Constitutive BAK activation as a determinant of drug sensitivity in malignant lymphohematopoietic cells

    PubMed Central

    Dai, Haiming; Ding, Husheng; Meng, X. Wei; Peterson, Kevin L.; Schneider, Paula A.; Karp, Judith E.; Kaufmann, Scott H.

    2015-01-01

    Mitochondrial outer membrane permeabilization (MOMP), a key step in the intrinsic apoptotic pathway, is incompletely understood. Current models emphasize the role of BH3-only BCL2 family members in BAX and BAK activation. Here we demonstrate concentration-dependent BAK autoactivation under cell-free conditions and provide evidence that this autoactivation plays a key role in regulating the intrinsic apoptotic pathway in intact cells. In particular, we show that up to 80% of BAK (but not BAX) in lymphohematopoietic cell lines is oligomerized and bound to anti-apoptotic BCL2 family members in the absence of exogenous death stimuli. The extent of this constitutive BAK oligomerization is diminished by BAK knockdown and unaffected by BIM or PUMA down-regulation. Further analysis indicates that sensitivity of cells to BH3 mimetics reflects the identity of the anti-apoptotic proteins to which BAK is constitutively bound, with extensive BCLXL•BAK complexes predicting navitoclax sensitivity, and extensive MCL1•BAK complexes predicting A1210477 sensitivity. Moreover, high BAK expression correlates with sensitivity of clinical acute myelogenous leukemia to chemotherapy, whereas low BAK levels correlate with resistance and relapse. Collectively, these results inform current understanding of MOMP and provide new insight into the ability of BH3 mimetics to induce apoptosis without directly activating BAX or BAK. PMID:26494789

  16. Reliability of antimalarial sensitivity tests depends on drug mechanisms of action.

    PubMed

    Wein, Sharon; Maynadier, Marjorie; Tran Van Ba, Christophe; Cerdan, Rachel; Peyrottes, Suzanne; Fraisse, Laurent; Vial, Henri

    2010-05-01

    In vitro antimalarial activity tests play a pivotal role in malaria drug research or for monitoring drug resistance in field isolates. We applied two isotopic tests, two enzyme-linked immunosorbent assays (ELISA) and the SYBR green I fluorescence-based assay, to test artesunate and chloroquine, the metabolic inhibitors atovaquone and pyrimethamine, our fast-acting choline analog T3/SAR97276, and doxycycline, which has a delayed death profile. Isotopic tests based on hypoxanthine and ethanolamine incorporation are the most reliable tests provided when they are applied after one full 48-h parasite cycle. The SYBR green assay, which measures the DNA content, usually requires 72 h of incubation to obtain reliable results. When delayed death is suspected, specific protocols are required with increasing incubation times up to 96 h. In contrast, both ELISA tests used (pLDH and HRP2) appear to be problematic, leading to disappointing and even erroneous results for molecules that do not share an artesunatelike profile. The reliability of these tests is linked to the mode of action of the drug, and the conditions required to get informative results are hard to predict. Our results suggest some minimal conditions to apply these tests that should give rise to a standard 50% inhibitory concentration, regardless of the mechanism of action of the compounds, and highlight that the most commonly used in vitro antimalarial activity tests do not have the same potential. Some of them might not detect the antimalarial potential of new classes of compounds with innovative modes of action, which subsequently could become promising new antimalarial drugs.

  17. Molecular Determinants of Antiestrogen and Drug Sensitivity in Breast Carcinoma Cells

    DTIC Science & Technology

    1997-08-01

    lines , including MCF7, with the bacterial Lacl repressor gene, modified for nuclear localization in mammalian cells . We have also generated a...still suitable for selection with cytotoxic drugs. To generate an ER-positive cell line susceptible to ecotropic retroviruses, we have transfected an...and functional activity in retroviral vectors, we have developed new vectors, GSE isolation procedures and recipient cell lines . We have also

  18. Mesoscale Simulations and Experimental Studies of pH-Sensitive Micelles for Controlled Drug Delivery.

    PubMed

    Wang, Yan; Li, Qiu Yu; Liu, Xu Bo; Zhang, Can Yang; Wu, Zhi Min; Guo, Xin Dong

    2015-11-25

    The microstructures of doxorubicin-loaded micelles prepared from block polymers His(x)Lys10 (x = 0, 5, 10) conjugated with docosahexaenoic acid (DHA) are investigated under different pH conditions, using dissipative particle dynamics (DPD) simulations. The conformation of micelles and the DOX distributions in micelles were obviously influenced by pH values and the length of the histidine segment. At pH >6.0, the micelles self-assembled from the polymers were dense and compact. The drugs were entrapped well within the micellar core. The particle size increases as the histidine length increases. With the decrease of pH value to be lower than 6.0, there was no distinct difference for the micelles self-assembled from the polymer without histidine residues. However, the micelles prepared from the polymers with histidine residues shows a structural transformation from dense to swollen conformation, leading to an increased particle size from 10.3 to 14.5 DPD units for DHD-His10Lys10 micelles. This structural transformation of micelles can accelerate the DOX release from micelles under lower pH conditions. The in vitro drug release from micelles is accelerated by the decrease of pH value from 7.4 (physiological environment) to 5.0 (lysosomal environment). The integration of simulation and experiments might be a valuable method for the optimization and design of biomaterials for drug delivery with desired properties.

  19. Towards automated production and drug sensitivity testing using scaffold-free spherical tumor microtissues.

    PubMed

    Drewitz, Maren; Helbling, Marianne; Fried, Nicole; Bieri, Manuela; Moritz, Wolfgang; Lichtenberg, Jan; Kelm, Jens M

    2011-12-01

    Although the relevance of three-dimensional (3-D) culture has been recognized for years and exploited at an academic level, its translation to industrial applications has been slow. The development of reliable high-throughput technologies is clearly a prerequisite for the industrial implementation of 3-D models. In this study the robustness of spherical microtissue production and drug testing in a 96-well hanging-drop multiwell plate format was assessed on a standard 96-well channel robotic platform. Microtissue models derived from six different cell lines were produced and characterized according to their growth profile and morphology displaying high-density tissue-like reformation and growth over at least 15 days. The colon cancer cell line HCT116 was chosen as a model to assess microtissue-based assay reproducibility. Within three individual production batches the size variations of the produced microtissues were below 5%. Reliability of the microtissue-based assay was tested using two reference compounds, staurosporine and chlorambucil. In four independent drug testings the calculated IC(50) values were benchmarked against 2-D multiwell testings displaying similar consistency. The technology presented here for the automated production of a variety of microtissues for efficacy testing in a standard 96-well format will aid the implementation of more organotypic models at an early time point in the drug discovery process.

  20. Stimuli sensitive polymers and self regulated drug delivery systems: a very partial review.

    PubMed

    Siegel, Ronald A

    2014-09-28

    Since the early days of the Journal of Controlled Release, there has been considerable interest in materials that can release drug on an "on-demand" basis. So called "stimuli-responsive" and "intelligent" systems have been designed to deliver drug at various times or at various sites in the body, according to a stimulus that is either endogenous or externally applied. In the past three decades, research along these lines has taken numerous directions, and each new generation of investigators has discovered new physicochemical principles and chemical schemes by which the release properties of materials can be altered. No single review could possibly do justice to all of these approaches. In this article, some general observations are made, and a partial history of the field is presented. Both open loop and closed loop systems are discussed. Special emphasis is placed on stimuli-responsive hydrogels, and on systems that can respond repeatedly. It is argued that the most success at present and in the foreseeable future is with systems in which biosensing and actuation (i.e. drug delivery) are separated, with a human and/or cybernetic operator linking the two.

  1. Molecular mechanism of drug photosensitization. 7. Photocleavage of DNA sensitized by suprofen.

    PubMed

    Condorelli, G; Constanzo, L L; De Guidi, G; Giuffrida, S; Sortino, S

    1995-07-01

    Ultraviolet-A irradiation of a suprofen (2-[4-2(2-thenoyl) phenyl]propionic acid) (SPF) buffered solution (pH 7.4) in the presence of supercoiled pBR322 DNA leads to single strand breaks with the formation of an open circular form and subsequent linearization of the plasmid. On the basis of agarose gel electrophoresis data of samples irradiated in an air-saturated solution or in an oxygen-modified atmosphere, and the effects of sodium azide, D20, mannitol, copper(II), superoxide dismutase, 2-H-propanol, deferoxamine and surfactants, we suggest a photosensitization mechanism involving singlet oxygen and free radicals. The higher rate of photocleavage in nitrogen compared to that in an air-saturated solution and the results obtained from oxygen consumption measurements support the hypothesis that both the type I and type II photosensitization mechanisms are operative and that oxygen quenches the excited state of the irradiated drug. The photosensitization model applied was in agreement with that previously applied to cell membrane SPF photoinduced damage. Interaction of the drug with DNA, studied through circular dichroism and fluorescence anisotropy, probably occurs through a surface binding mode. The experimental techniques used for assessing the photodamaging activity of this drug may be useful for screening of phototoxic compounds in the environment and for determining the active species involved.

  2. Stimuli Sensitive Polymers and Self Regulated Drug Delivery Systems: A Very Partial Review

    PubMed Central

    Siegel, Ronald A.

    2014-01-01

    Since the early days of the Journal of Controlled Release, there has been considerable interest in materials that can release drug on an “on-demand” basis. So called “stimuli-responsive” and “intelligent” systems have been designed to deliver drug at various times or at various sites in the body, according to a stimulus that is either endogenous or externally applied. In the past three decades, research along these lines has taken numerous directions, and each new generation of investigators has discovered new physicochemical principles and chemical schemes by which the release properties of materials can be altered. No single review could possibly do justice to all of these approaches. In this article, some general observations are made, and a partial history of the field is presented. Both open loop and closed loop systems are discussed. Special emphasis is placed on stimuli-responsive hydrogels, and on systems that can respond repeatedly. It is argued that the most success at present and in the foreseeable future is with systems in which biosensing and actuation (i.e. drug delivery) are separated, with a human and/or cybernetic operator linking the two. PMID:24984012

  3. An intelligent multicompartmental system based on thermo-sensitive starch microspheres for temperature-controlled release of drugs.

    PubMed

    Fundueanu, Gheorghe; Constantin, Marieta; Ascenzi, Paolo; Simionescu, Bogdan C

    2010-08-01

    An original multicompartmental drug delivery system based on encapsulation of "intelligent" starch microspheres was designed and developed. Starch microspheres with thermo-responsive properties and possessing strong anionic functional groups (-SO(3)H), capable to bind electrostatically drugs, has been prepared. Firstly, the thermo-responsive units based on copolymer of poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) with a lower critical solution temperature around 36 degrees C, were grafted on preformed starch microspheres. Secondly, the strong anionic groups (-SO(3)H) were introduced by sequential grafting of 2-acrylamido-2-methyl-1-propanesulfonic acid on the remaining--OH groups of starch. The thermo-sensitive microspheres with sulfonic groups display a sharp phase transition around the human body temperature. They were complexed with the positively-charged metoclopramide (low molecular weight model drug) and then encapsulated in cellulose acetate butyrate microcapsules by an oil-in-water solvent evaporation method. The swelling and diffusion of encapsulated microspheres to the aqueous continuous phase is avoided because the temperature of aqueous phase is higher than volume phase transition temperature (VPTT) of microspheres. This multicompartmental device could develop the background of "smart" implantable drug delivery system for persons that work in dangerous cold places (builders, climbers). When the temperature of the human body decreases below the normal temperature (the threshold temperature could be tuned), the encapsulated microspheres swell extensively in contact with physiological fluids, break the microcapsules and a large amount of bioactive compounds is released, keeping the activity of the vital organs. In normal physiological conditions (above LCST), the microspheres slightly swell, fill up the microcavities of microcapsules, but do not break them and release the drug in microcompartments. These microcompartments become microreservoirs

  4. An intravenous exposure mouse model for prediction of potential drug-sensitization using reporter antigens popliteal lymph node assay.

    PubMed

    Lin, Mingbao; Sun, Wei; Wang, Yingchao; Li, Xiang; Jin, Yecheng; Gong, Wan; Fan, Xiaohui; Wang, Yi

    2012-06-01

    Immune-mediated drug hypersensitivity is a particularly concerning health-safety issue among clinicians given its unpredictability and potentially life-threatening effects, especially with exposure to intravenous drugs. Therefore, the development of intravenous drug-exposure models for drug-hazard assessments has garnered increasing interest in recent years. In this study, we used reporter antigens popliteal lymph node assay to investigate the potential value of intravenous exposure to a selected variety of allergenic compounds, including ovalbumin (OVA), concanavalin A (ConA) and diclofenac. The trinitrophenyl (TNP)-specific antibody-forming cells were used to assess the systemic immune responses to a bystander antigen. Mice were subsequently sensitized by TNP-OVA, and then intravenous exposure to one of the selective compounds. As expected, all positive compounds induced significant popliteal lymph node (PLN) proliferation compared with the control. OVA significantly increased Cluster of Differentiation 4 receptors (CD⁴)⁺ interleukin-4 (IL-4)⁺ T-helper 2 (Th2) cells and, consequently, increased the ratios of IL-4/interferon-γ (IFN-γ) antibody-forming cells (AFCs) in PLNs, while bringing about a dose-dependent increase in immunoglobulin G1 (IgG1) AFCs; these findings indicate that a Th2 hypersensitivity response was induced. A Th2 response was also observed in diclofenac sodium-treated groups, and for ConA, a more mixed Th1/Th2 immune response appeared to be induced. In addition, there was no marked reaction with the negative compound. Together, it seems likely that the intravenous exposure model may be useful for drug-induced systemic hypersensitivity assessments.

  5. Effect of YB-1 on the regulation of micro RNA expression in drug-sensitive and drug-resistant gastric carcinoma cells.

    PubMed

    Belian, Elisa; Kurucz, Reka; Treue, Denise; Lage, Hermann

    2010-02-01

    The multifunctional Y-Box protein 1 (YB-1) exerts positive and negative regulatory effects on gene expression by different mechanisms. Since transcription can be controlled by micro RNAs (miRNAs), YB-1 could also cause effects on gene expression by regulation of cellular miRNAs. To test this hypothesis, a previously established and well-characterized cell model derived from drug-sensitive (EPG85-257P/tetR/YB-1) and multidrug-resistant (EPG85-257RDB/tetR/YB-1) gastric carcinoma cells, in which the expression of YB-1 can be inhibited by tetracycline-dependent triggering of the RNA interference (RNAi) pathway, was investigated concerning their miRNA expression profiles in the presence and absence of YB-1. Microarray hybridizations demonstrated that six miRNAs (miR-96*, miR-210, miR-503, miR-623, miR-1275, miR-1290) were up-regulated more than 1.5-fold in drug-sensitive cells following YB-1 inhibition, but no differences in miRNA expression could be detected in multidrug-resistant cells. Independent validation of these findings by quantitative real-time reverse transcriptase polymerase chain reaction did not confirm these effects. Likewise, an in silico analysis of potential regulatory effects of the miRNAs on their target genes did not support the potential miRNA regulatory effects of YB-1. In conclusion, the data provide evidence that YB-1 has no direct influence on global miRNA expression pattern in different variants of gastric carcinoma cells and, therewith, does not control gene expression by regulation of miRNAs.

  6. Conditionally replicating luciferase reporter phages: improved sensitivity for rapid detection and assessment of drug susceptibility of Mycobacterium tuberculosis.

    PubMed Central

    Carrière, C; Riska, P F; Zimhony, O; Kriakov, J; Bardarov, S; Burns, J; Chan, J; Jacobs, W R

    1997-01-01

    TM4 is a lytic mycobacteriophage which infects mycobacteria of clinical importance. A luciferase reporter phage, phAE40, has been constructed from TM4 and was previously shown to be useful for the rapid detection and drug susceptibility testing of Mycobacterium tuberculosis. However, the lytic nature of the phage results in a loss of detectable light output and limits the sensitivity of detection. We describe several strategies aimed at improving the luciferase activity generated by TM4 luciferase phages, including (i) varying the position of the luciferase gene in the phage genome, (ii) isolating host-range mutants of the phage, and (iii) introducing temperature-sensitive mutations in the phage such that it will not replicate at the infecting temperature. Several new phages generated by these methods show increased intensity of luciferase production compared to the first-generation reporter phage phAE40, and one phage, phAE88, also demonstrates an enhanced duration of luciferase activity. This has allowed the detection of as few as 120 BCG cells and the determination of drug susceptibilities of M. tuberculosis in as little as 1 day. PMID:9399525

  7. Properties of recombinant human N1-acetylpolyamine oxidase (hPAO): potential role in determining drug sensitivity.

    PubMed

    Wang, Yanlin; Hacker, Amy; Murray-Stewart, Tracy; Frydman, Benjamin; Valasinas, Aldonia; Fraser, Alison V; Woster, Patrick M; Casero, Robert A

    2005-07-01

    The recent cloning of the mammalian gene coding for N(1)-acetylpolyamine oxidase (PAO) provides the opportunity to directly examine the role of human PAO (hPAO) in polyamine homeostasis as well as its potential role in determining cellular response to antitumor polyamine analogues. To facilitate the study of this enzyme, the production, purification, and characterization of the recombinant hPAO is reported. hPAO oxidizes N(1)-acetylspermidine (K(m)=2.1 microM, K(cat)=15.0 s(-1)) and has very high affinity for N(1)-acetylspermine (K(m)=0.85 microM, K(cat)=31.7 s(-1)). The recombinant hPAO does not efficiently oxidize spermine, thereby demonstrating a significant difference in substrate specificity from the previously described human spermine oxidase PAOh1/SMO. Importantly, hPAO demonstrates the ability to oxidize a subset of antitumor polyamine analogues, suggesting that this oxidase activity could have a significant effect on determining tumor sensitivity to these or similar agents. Transfection of A549 human lung cancer cells with an hPAO-expressing plasmid leads to a profound decrease in sensitivity to those analogues which act as substrates, confirming its potential to alter drug response. One similarity that hPAO shares with human PAOh1/SMO, is that certain oligoamine analogues are potent inhibitors of its oxidase activity. The results of these studies demonstrate how changes in polyamine catabolism may affect drug response.

  8. Dextran hydrogel coated surface plasmon resonance imaging (SPRi) sensor for sensitive and label-free detection of small molecule drugs

    NASA Astrophysics Data System (ADS)

    Li, Shaopeng; Yang, Mo; Zhou, Wenfei; Johnston, Trevor G.; Wang, Rui; Zhu, Jinsong

    2015-11-01

    The label-free and sensitive detection of small molecule drugs on SPRi is still a challenging task, mainly due to the limited surface immobilization capacity of the sensor. In this research, a dextran hydrogel-coated gold sensor chip for SPRi was successfully fabricated via photo-cross-linking for enhanced surface immobilization capacity. The density of the dextran hydrogel was optimized for protein immobilization and sensitive small molecule detection. The protein immobilization capacity of the hydrogel was 10 times greater than a bare gold surface, and 20 times greater than an 11-mercaptoundecanoic acid (MUA) surface. Such a drastic improvement in immobilization capacity allowed the SPRi sensor to detect adequate response signals when probing small molecule binding events. The binding signal of 4 nM liquid-phase biotin to streptavidin immobilized on the dextran surface reached 435 RU, while no response was observed on bare gold or MUA surfaces. The dextran hydrogel-coated SPRi sensor was also applied in a kinetic study of the binding between an immunosuppressive drug (FK506) and its target protein (FKBP12) in a high-throughput microarray format. The measured binding affinity was shown to be consistent with reported literature values, and a detection limit of 0.5 nM was achieved.

  9. Long-term exposure to abnormal glucose levels alters drug metabolism pathways and insulin sensitivity in primary human hepatocytes

    PubMed Central

    Davidson, Matthew D.; Ballinger, Kimberly R.; Khetani, Salman R.

    2016-01-01

    Hyperglycemia in type 2 diabetes mellitus has been linked to non-alcoholic fatty liver disease, which can progress to inflammation, fibrosis/cirrhosis, and hepatocellular carcinoma. Understanding how chronic hyperglycemia affects primary human hepatocytes (PHHs) can facilitate the development of therapeutics for these diseases. Conversely, elucidating the effects of hypoglycemia on PHHs may provide insights into how the liver adapts to fasting, adverse diabetes drug reactions, and cancer. In contrast to declining PHH monocultures, micropatterned co-cultures (MPCCs) of PHHs and 3T3-J2 murine embryonic fibroblasts maintain insulin-sensitive glucose metabolism for several weeks. Here, we exposed MPCCs to hypo-, normo- and hyperglycemic culture media for ~3 weeks. While albumin and urea secretion were not affected by glucose level, hypoglycemic MPCCs upregulated CYP3A4 enzyme activity as compared to other glycemic states. In contrast, hyperglycemic MPCCs displayed significant hepatic lipid accumulation in the presence of insulin, while also showing decreased sensitivity to insulin-mediated inhibition of glucose output relative to a normoglycemic control. In conclusion, we show for the first time that PHHs exposed to hypo- and hyperglycemia can remain highly functional, but display increased CYP3A4 activity and selective insulin resistance, respectively. In the future, MPCCs under glycemic states can aid in novel drug discovery and mechanistic investigations. PMID:27312339

  10. pH-Sensitive, N-ethoxybenzylimidazole (NEBI) bifunctional crosslinkers enable triggered release of therapeutics from drug delivery carriers.

    PubMed

    Luong, Alice; Issarapanichkit, Tawny; Kong, Seong Deok; Fong, Rina; Yang, Jerry

    2010-11-21

    This paper presents a pH-sensitive bifunctional crosslinker that enables facile conjugation of small molecule therapeutics to macromolecular carriers for use in drug delivery systems. This N-ethoxybenzylimidazole (NEBI) bifunctional crosslinker was designed to exploit mildly acidic, subcellular environments to trigger the release of therapeutics upon internalization in cells. We demonstrate that an analog of doxorubicin (a representative example of an anticancer therapeutic) conjugated to human serum albumin (HSA, a representative example of a macromolecular carrier) via this NEBI crosslinker can internalize and localize into acidic lysosomes of ovarian cancer cells. Fluorescence imaging and cell viability studies demonstrate that the HSA-NEBI-doxorubicin conjugate exhibited improved uptake and cytotoxic activity compared to the unconjugated doxorubicin analog. The pH-sensitive NEBI group was also shown to be relatively stable to biologically-relevant metal Lewis acids and to serum proteins, supporting that these bifunctional crosslinkers may be useful for constructing drug delivery systems that will be stable in biological fluids such as blood.

  11. Enhancement of neutrophil autophagy by an IVIG preparation against multidrug-resistant bacteria as well as drug-sensitive strains.

    PubMed

    Itoh, Hiroshi; Matsuo, Hidemasa; Kitamura, Naoko; Yamamoto, Sho; Higuchi, Takeshi; Takematsu, Hiromu; Kamikubo, Yasuhiko; Kondo, Tadakazu; Yamashita, Kouhei; Sasada, Masataka; Takaori-Kondo, Akifumi; Adachi, Souichi

    2015-07-01

    Autophagy occurs in human neutrophils after the phagocytosis of multidrug-resistant bacteria and drug-sensitive strains, including Escherichia coli and Pseudomonas aeruginosa. The present study detected autophagy by immunoblot analysis of LC3B conversion, by confocal scanning microscopic examination of LC3B aggregate formation and by transmission electron microscopic examination of bacteria-containing autophagosomes. Patients with severe bacterial infections are often treated with IVIG alongside antimicrobial agents. Here, we showed that IVIG induced neutrophil-mediated phagocytosis of multidrug-resistant strains. Compared with untreated neutrophils, neutrophils exposed to IVIG showed increased levels of bacterial cell killing, phagocytosis, O(2)(-) release, MPO release, and NET formation. IVIG also increased autophagy in these cells. Inhibiting the late phase of autophagy (fusion of lysosomes with autophagosomes) with bafilomycin A1-reduced, neutrophil-mediated bactericidal activity. These findings indicate that autophagy plays a critical role in the bactericidal activity mediated by human neutrophils. Furthermore, the autophagosomes within the neutrophils contained bacteria only and their organelles only, or both bacteria and their organelles, a previously undocumented observation. Taken together, these results suggest that the contents of neutrophil autophagosomes may be derived from specific autophagic systems, which provide the neutrophil with an advantage. Thus, IVIG promotes the neutrophil-mediated killing of multidrug-resistant bacteria as well as drug-sensitive strains.

  12. Long-term exposure to abnormal glucose levels alters drug metabolism pathways and insulin sensitivity in primary human hepatocytes

    NASA Astrophysics Data System (ADS)

    Davidson, Matthew D.; Ballinger, Kimberly R.; Khetani, Salman R.

    2016-06-01

    Hyperglycemia in type 2 diabetes mellitus has been linked to non-alcoholic fatty liver disease, which can progress to inflammation, fibrosis/cirrhosis, and hepatocellular carcinoma. Understanding how chronic hyperglycemia affects primary human hepatocytes (PHHs) can facilitate the development of therapeutics for these diseases. Conversely, elucidating the effects of hypoglycemia on PHHs may provide insights into how the liver adapts to fasting, adverse diabetes drug reactions, and cancer. In contrast to declining PHH monocultures, micropatterned co-cultures (MPCCs) of PHHs and 3T3-J2 murine embryonic fibroblasts maintain insulin-sensitive glucose metabolism for several weeks. Here, we exposed MPCCs to hypo-, normo- and hyperglycemic culture media for ~3 weeks. While albumin and urea secretion were not affected by glucose level, hypoglycemic MPCCs upregulated CYP3A4 enzyme activity as compared to other glycemic states. In contrast, hyperglycemic MPCCs displayed significant hepatic lipid accumulation in the presence of insulin, while also showing decreased sensitivity to insulin-mediated inhibition of glucose output relative to a normoglycemic control. In conclusion, we show for the first time that PHHs exposed to hypo- and hyperglycemia can remain highly functional, but display increased CYP3A4 activity and selective insulin resistance, respectively. In the future, MPCCs under glycemic states can aid in novel drug discovery and mechanistic investigations.

  13. Dissolution evaluation in vitro and bioavailability in vivo of self-microemulsifying drug delivery systems for pH-sensitive drug loratadine.

    PubMed

    Li, Haiyan; Tan, Yonggang; Yang, Lixia; Gao, Lijun; Wang, Tao; Yang, Xi; Quan, Dongqin

    2015-01-01

    The aim of this study was to improve the oral absorption of loratadine, a pH-sensitive drug, by self-microemulsifying drug delivery systems (SMEDDSs). The optimal SMEDDS was analysed and evaluated after emulsification in distilled water with diameter of 26.57 ± 0.71 nm and zeta potential of -30.5 ± 4.5 mV. Dissolution experiments in vitro were carried out in different released media of pH values and the SMEDDS formulations were able to release loratadine completely in different media while market tablets just performed similarly in the media of pH 1.2. Furthermore, the oral bioavailability and the pharmacokinetic behaviour of loratadine formulations in vivo were studied after a single dose of 1 mg/kg loratadine in beagle dogs. The SMEDDS formulations displayed higher Cmax and AUC, approximately 9 and 5 times increase than those of market tablets (p < 0.01) respectively. These results demonstrated that SMEDDS formulations had significantly increased the oral absorption of loratadine in beagle dogs.

  14. Discovery of monocarbonyl curcumin-BTP hybrids as STAT3 inhibitors for drug-sensitive and drug-resistant breast cancer therapy

    PubMed Central

    Zhang, Wenda; Guo, Jianpeng; Li, Shanshan; Ma, Ting; Xu, Dingqiao; Han, Chao; Liu, Feiyan; Yu, Wenying; Kong, Lingyi

    2017-01-01

    Signal transducer and activator of transcription 3 (STAT3) is a well-known antitumor target. Exogenous ROS insult can lead to selective cytotoxicity against cancer cells. A combination of STAT3 inhibition and “oxidation therapy” may be a new strategy to address the multidrug-resistance issue due to their important roles in the survival and drug resistance of cancer cells. Here, a series of novel curcumin-BTP hybrids were designed and evaluated as STAT3 inhibitors with ROS production activity. Compound 6b exerted the best antitumor activity and selectivity for MCF-7 and MCF-7/DOX cells (IC50 = 0.52 μM and 0.40 μM, respectively), while its IC50 value for MCF-10A breast epithelial cells was 7.72 μM. Furthermore, compound 6b suppressed STAT3 phosphorylation, nuclear translocation and DNA-binding activity and the expression of STAT3 specific oncogenes. Increases in the level of IL-6-induced p-STAT3 were also inhibited by 6b without influencing IFN-γ-induced p-STAT1 expression. Additionally, 6b effectively promoted intracellular ROS accumulation, induced cancer cell apoptosis and cell cycle arrest, abolished the colony formation ability of breast cancer cells, and inhibited P-gp expression in MCF-7/DOX cells. Finally, 6b suppressed the growth of implanted human breast cancer in vivo. Our findings highlight that 6b may be a promising therapeutic agent for drug-sensitive and drug-resistant breast cancers.

  15. Endogenous stimuli-sensitive multistage polymeric micelleplex anticancer drug delivery system for efficient tumor penetration and cellular internalization.

    PubMed

    Li, Junjie; Ke, Wendong; Li, Hui; Zha, Zengshi; Han, Yu; Ge, Zhishen

    2015-10-28

    To efficiently deliver anticancer drugs to the entire tumor tissue and cancer cells, an endogenous stimuli-sensitive multistage polymeric micelleplex drug delivery system is developed via electrostatic complexation between poly(ethylene glycol)-block-poly[(N'-dimethylmaleoyl-2-aminoethyl)aspartamide]-block-poly(ε-caprolactone) (PEG-b-PAsp(EDA-DM)-b-PCL) triblock copolymer micelles and cisplatin prodrug (Pt(IV))-conjugated cationic poly(amidoamine) dendrimers (PAMAM-Pt(IV)). The micelleplexes maintain structural stability at pH 7.4 ensuring long blood circulation and high tumor accumulation level, while they exhibit triggered release of secondary PAMAM-Pt(IV) dendrimer nanocarriers at tumoral acidity (≈pH 6.8) due to acid-labile charge-reversal properties of PAsp(EDA-DM) component under mildly acidic condition. The released PAMAM delivery nanocarriers with small size and slightly positive charges exhibit significantly deep tumor tissue penetration and efficient cellular internalization, followed by release of active cisplatin anticancer drug in intracellular reducing medium. In vivo investigation reveals that the Pt(IV)-loading micelleplexes significantly suppress tumor growth via intravenous injection due to synergistic effect of long circulation in bloodstream, high tumor accumulation, deep tumor tissue penetration, and efficient cellular internalization. Thus, the micelleplexes with stimuli-responsive multistage release feature show great potentials for better therapeutic efficacy of cancer especially through enhanced tumor penetration and cellular internalization.

  16. Assessment of Drug Sensitivity in Hematopoietic Stem and Progenitor Cells From Acute Myelogenous Leukemia and Myelodysplastic Syndrome Ex Vivo.

    PubMed

    Knorr, Katherine L B; Finn, Laura E; Smith, B Douglas; Hess, Allan D; Foran, James M; Karp, Judith E; Kaufmann, Scott H

    2016-11-07

    : Current understanding suggests that malignant stem and progenitor cells must be reduced or eliminated for prolonged remissions in myeloid neoplasms such as acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS). Multicolor flow cytometry has been widely used to distinguish stem and myeloid progenitor cells from other populations in normal and malignant bone marrow. In this study, we present a method for assessing drug sensitivity in MDS and AML patient hematopoietic stem and myeloid progenitor cell populations ex vivo using the investigational Nedd8-activating enzyme inhibitor MLN4924 and standard-of-care agent cytarabine as examples. Utilizing a multicolor flow cytometry antibody panel for identification of hematopoietic stem cells, multipotent progenitors, common myeloid progenitors, granulocyte-monocyte progenitors, and megakaryocyte-erythroid progenitors present in mononuclear cell fractions isolated from bone marrow aspirates, we compare stem and progenitor cell counts after treatment for 24 hours with drug versus diluent. We demonstrate that MLN4924 exerts a cytotoxic effect on MDS and AML stem and progenitor cell populations, whereas cytarabine has more limited effects. Further application of this method for evaluating drug effects on these populations ex vivo and in vivo may inform rational design and selection of therapies in the clinical setting.

  17. Assessment of Drug Sensitivity in Hematopoietic Stem and Progenitor Cells from Acute Myelogenous Leukemia and Myelodysplastic Syndrome Ex Vivo.

    PubMed

    Knorr, Katherine L B; Finn, Laura E; Smith, B Douglas; Hess, Allan D; Foran, James M; Karp, Judith E; Kaufmann, Scott H

    2017-03-01

    Current understanding suggests that malignant stem and progenitor cells must be reduced or eliminated for prolonged remissions in myeloid neoplasms such as acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS). Multicolor flow cytometry has been widely used to distinguish stem and myeloid progenitor cells from other populations in normal and malignant bone marrow. In this study, we present a method for assessing drug sensitivity in MDS and AML patient hematopoietic stem and myeloid progenitor cell populations ex vivo using the investigational Nedd8-activating enzyme inhibitor MLN4924 and standard-of-care agent cytarabine as examples. Utilizing a multicolor flow cytometry antibody panel for identification of hematopoietic stem cells, multipotent progenitors, common myeloid progenitors, granulocyte-monocyte progenitors, and megakaryocyte-erythroid progenitors present in mononuclear cell fractions isolated from bone marrow aspirates, we compare stem and progenitor cell counts after treatment for 24 hours with drug versus diluent. We demonstrate that MLN4924 exerts a cytotoxic effect on MDS and AML stem and progenitor cell populations, whereas cytarabine has more limited effects. Further application of this method for evaluating drug effects on these populations ex vivo and in vivo may inform rational design and selection of therapies in the clinical setting. Stem Cells Translational Medicine 2017;6:840-850.

  18. Highly sensitive capillary electrophoresis-mass spectrometry for rapid screening and accurate quantitation of drugs of abuse in urine.

    PubMed

    Kohler, Isabelle; Schappler, Julie; Rudaz, Serge

    2013-05-30

    The combination of capillary electrophoresis (CE) and mass spectrometry (MS) is particularly well adapted to bioanalysis due to its high separation efficiency, selectivity, and sensitivity; its short analytical time; and its low solvent and sample consumption. For clinical and forensic toxicology, a two-step analysis is usually performed: first, a screening step for compound identification, and second, confirmation and/or accurate quantitation in cases of presumed positive results. In this study, a fast and sensitive CE-MS workflow was developed for the screening and quantitation of drugs of abuse in urine samples. A CE with a time-of-flight MS (CE-TOF/MS) screening method was developed using a simple urine dilution and on-line sample preconcentration with pH-mediated stacking. The sample stacking allowed for a high loading capacity (20.5% of the capillary length), leading to limits of detection as low as 2 ng mL(-1) for drugs of abuse. Compound quantitation of positive samples was performed by CE-MS/MS with a triple quadrupole MS equipped with an adapted triple-tube sprayer and an electrospray ionization (ESI) source. The CE-ESI-MS/MS method was validated for two model compounds, cocaine (COC) and methadone (MTD), according to the Guidance of the Food and Drug Administration. The quantitative performance was evaluated for selectivity, response function, the lower limit of quantitation, trueness, precision, and accuracy. COC and MTD detection in urine samples was determined to be accurate over the range of 10-1000 ng mL(-1) and 21-1000 ng mL(-1), respectively.

  19. Multifunctional pH-sensitive magnetic nanoparticles for simultaneous imaging, sensing and targeted intracellular anticancer drug delivery

    NASA Astrophysics Data System (ADS)

    Banerjee, Shashwat S.; Chen, Dong-Hwang

    2008-12-01

    A novel multifunctional magnetic nanocarrier was fabricated for synchronous cancer therapy and sensing. The nanocarrier, programed to display a response to environmental stimuli (pH value), was synthesized by coupling doxorubicin (DOX) to adipic dihydrazide-grafted gum arabic modified magnetic nanoparticles (ADH-GAMNP) via the hydrolytically degradable pH-sensitive hydrazone bond. The resultant nanocarrier, DOX-ADH-GAMNP, had a mean diameter of 13.8 nm and the amount of DOX coupled was about 6.52 mg g-1. Also, it exhibited pH triggered release of DOX in an acidic environment (pH 5.0) but was relatively stable at physiological pH (pH 7.4). Furthermore, both GAMNP and DOX were found to possess fluorescence properties when excited in the near-infrared region due to the two-photon absorption mechanism. The coupling of DOX to GAMNP resulted in a reversible self-quenching of fluorescence through the fluorescence resonant energy transfer (FRET) between the donor GAMNP and acceptor DOX. The release of DOX from DOX-ADH-GAMNP when exposed to acidic media indicated the recovery of fluorescence from both GAMNP and DOX. The change in the fluorescence intensity of DOX-ADH-GAMNP on the release of DOX can act as a potential sensor to sense the delivery of the drug. The analysis of zeta potential and plasmon absorbance in different pH conditions also confirmed the pH sensitivity of the product. This multifunctional nanocarrier is a significant breakthrough in developing a drug delivery vehicle that combines drug targeting as well as sensing and therapy at the same time.

  20. Multifunctional pH-sensitive magnetic nanoparticles for simultaneous imaging, sensing and targeted intracellular anticancer drug delivery.

    PubMed

    Banerjee, Shashwat S; Chen, Dong-Hwang

    2008-12-17

    A novel multifunctional magnetic nanocarrier was fabricated for synchronous cancer therapy and sensing. The nanocarrier, programed to display a response to environmental stimuli (pH value), was synthesized by coupling doxorubicin (DOX) to adipic dihydrazide-grafted gum arabic modified magnetic nanoparticles (ADH-GAMNP) via the hydrolytically degradable pH-sensitive hydrazone bond. The resultant nanocarrier, DOX-ADH-GAMNP, had a mean diameter of 13.8 nm and the amount of DOX coupled was about 6.52 mg g(-1). Also, it exhibited pH triggered release of DOX in an acidic environment (pH 5.0) but was relatively stable at physiological pH (pH 7.4). Furthermore, both GAMNP and DOX were found to possess fluorescence properties when excited in the near-infrared region due to the two-photon absorption mechanism. The coupling of DOX to GAMNP resulted in a reversible self-quenching of fluorescence through the fluorescence resonant energy transfer (FRET) between the donor GAMNP and acceptor DOX. The release of DOX from DOX-ADH-GAMNP when exposed to acidic media indicated the recovery of fluorescence from both GAMNP and DOX. The change in the fluorescence intensity of DOX-ADH-GAMNP on the release of DOX can act as a potential sensor to sense the delivery of the drug. The analysis of zeta potential and plasmon absorbance in different pH conditions also confirmed the pH sensitivity of the product. This multifunctional nanocarrier is a significant breakthrough in developing a drug delivery vehicle that combines drug targeting as well as sensing and therapy at the same time.

  1. βI-tubulin mutations in the laulimalide/peloruside binding site mediate drug sensitivity by altering drug-tubulin interactions and microtubule stability.

    PubMed

    Kanakkanthara, Arun; Rowe, Matthew R; Field, Jessica J; Northcote, Peter T; Teesdale-Spittle, Paul H; Miller, John H

    2015-09-01

    Peloruside A (PLA) and laulimalide (LAU) are potent microtubule-stabilizing natural products that are effective against a broad spectrum of cancer cells. The interactions of PLA and LAU with tubulin have attracted a great deal of attention, mainly because they bind to β-tubulin at a site that is different from the classical taxoid site. Multiple βI-tubulin amino acid residues have been predicted by computer modelling studies and more recently by protein crystallography to participate in the binding of PLA and LAU to tubulin. The relevance of these residues in determining cellular sensitivity to the compounds, however, remains largely uncertain. To determine the role of four binding site residues, Q291, D295, V333, and N337 on PLA and LAU activity, we introduced single mutations to these sites by site-directed mutagenesis and transfected each mutant tubulin separately into HEK and/or HeLa cells. We found that a Q291M βI-tubulin mutation increased sensitivity of the cells to PLA, but not to LAU, paclitaxel (PTX), or vinblastine (VBL). In contrast, V333W and N337L mutations led to less stable microtubules, with the V333W causing resistance to PLA and PTX, but not LAU, and the N337L causing resistance to PLA, LAU, and PTX. Moreover, cells expressing either W333 or L337 were hypersensitive to the microtubule-destabilizing agent, VBL. The D295I mutation conferred resistance to both PLA and LAU without affecting microtubule stability or sensitivity to PTX or ixabepilone (IXB). This study identifies the first mammalian βI-tubulin mutation that specifically increases sensitivity to PLA, and reports mutations at PLA and LAU binding site residues that can either reduce microtubule stability or impair drug-tubulin binding, conferring resistance to these microtubule-stabilizing agents. This information provides insights on β-tubulin residues important for maintaining microtubule structural integrity and for sensitivity to microtubule-targeting agents, and suggests novel

  2. In situ gelling pH- and temperature-sensitive biodegradable block copolymer hydrogels for drug delivery.

    PubMed

    Singh, Narendra K; Lee, Doo Sung

    2014-11-10

    Stimuli-sensitive injectable polymeric hydrogels have been extensively investigated during the past decade as bioactive agent delivery vehicles and for tissue engineering applications. An aqueous solution of these polymers undergoes a sol-to-gel phase transition in response to external stimuli such as pH, temperature, salt, light, biomolecules, electromagnetic field, etc. Bioactive molecules or cells can be mixed into the low-viscosity state of the polymer solution and injected into the body at a target site, forming an in situ hydrogel depot, which can then serve as bioactive-molecule-releasing carriers or a cell-growing microenvironment. This review systematically summarizes the recent progress in biodegradable and injectable block copolymer hydrogels, giving special attention to the novel and promising pH- and temperature-sensitive injectable block copolymer hydrogels for biomedical applications. The gelation mechanism, formation of ionic complexes, and biodegradation are highlighted as key factors responsible for controlled protein/drug delivery. The advantages and perspectives of pH- and temperature-sensitive injectable block copolymer hydrogels are also highlighted.

  3. Antibacterial effect of mango (Mangifera indica Linn.) leaf extract against antibiotic sensitive and multi-drug resistant Salmonella typhi.

    PubMed

    Hannan, Abdul; Asghar, Samra; Naeem, Tahir; Ikram Ullah, Muhammad; Ahmed, Ijaz; Aneela, Syeda; Hussain, Shabbir

    2013-07-01

    Alternative herbal medicine has been used to treat various infections from centuries. Natural plants contain phytoconstituents having similar chemical properties as of synthetic antibiotics. Typhoid fever is a serious infection and failure of its treatment emerged multi-drug resistant (MDR) bugs of Salmonella typhi. Due to multiple and repeated issues with antibiotics efficacy, it became essential to evaluate biological properties of plants from different geographical origins. Mango leaves have been Reported for various medicinal effects like antioxidant, antimicrobial, antihelminthic, antidiabetic and antiallergic etc. Objective of present study was to investigate anti-typhoid properties of acetone mango leaf extract (AMLE) against antibiotic sensitive and MDR S. typhi isolates. A total of 50 isolates of S. typhi including MDR (n=30) and antibiotic sensitive (n=20) were investigated. Staphylococcus aureus (ATCC 25923) and Salmonella typhimurium (ATCC14028) were used as quality control strains. AMLE was prepared and its antibacterial activity was evaluated by agar well diffusion screening method and minimum inhibitory concentration (MIC), by agar dilution technique. Zone of inhibition (mm) of AMLE against MDR and antibiotic sensitive isolates was 18±1.5mm (Mean±S.D). Zone of S. aureus (ATCC 25923) and S. typhimurium (ATCC14028) was 20±1.5mm (Mean±S.D). MIC of AMLE was Reported in range from 10-50 mg/ml. The present study described the inhibitory effects of mango leaves against S. typhi.

  4. Self-assembled nanocomplexes of anionic pullulan and polyallylamine for DNA and pH-sensitive intracellular drug delivery

    NASA Astrophysics Data System (ADS)

    Vora, Lalit; Tyagi, Monica; Patel, Ketan; Gupta, Sanjay; Vavia, Pradeep

    2014-12-01

    The amalgamation of chemotherapy and gene therapy is promising treatment option for cancer. In this study, novel biocompatible self-assembled nanocomplexes (NCs) between carboxylmethylated pullulan t335 (CMP) with polyallylamine (CMP-PAA NCs) were developed for plasmid DNA (pDNA) and pH-sensitive doxorubicin (DOX) delivery. DOX was conjugated to CMP (DOX-CMP) via hydrazone and confirmed by FTIR and 1H-NMR. In vitro release studies of pH-sensitive DOX-CMP conjugate showed 23 and 85 % release after 48 h at pH 7.4 (physiological pH) and pH 5 (intracellular/tumoral pH), respectively. The CMP-PAA NCs or DOX-CMP-PAA NCs self-assembled into a nanosized (<250 nm) spherical shape as confirmed by DLS and TEM. The hemolysis and cytotoxicity study indicated that the CMP-PAA NCs did not show cytotoxicity in comparison with plain polyallylamine. Gel retardation assay showed complete binding of pDNA with CMP-PAA NCs at 1:2 weight ratio. CMP-PAA NCs/pDNA showed significantly higher transfection in HEK293 cells compared to PAA/pDNA complexes. Confocal imaging demonstrated successful cellular uptake of DOX-CMP-PAA NCs in HEK293 cells. Thus, NCs hold great potential for targeted pDNA and pH-sensitive intratumoral drug delivery.

  5. A novel sensitive detection platform for antitumor herbal drug aloe-emodin based on the graphene modified electrode.

    PubMed

    Li, Juan; Chen, Jinghua; Zhang, Xiao-Long; Lu, Chun-Hua; Yang, Huang-Hao

    2010-12-15

    This paper has presented a novel strategy to carry out direct and sensitive determination of antitumor herbal drug aloe-emodin in complex matrices based on the graphene-Nafion modified glassy carbon (GN/GC) electrode. This proposed modified electrode showed good electrochemical response towards aloe-emodin (AE). Compared with the multiwall carbon nanotubes (MWCNTs) modified electrode, the GN/GC electrode has the advantages of higher sensitivity and lower cost. Under the optimized conditions, the calibration curve for AE concentration was linear in the range from 5 nmol/L to 1 μmol/L with the detection limit of 2 nmol/L. In addition, the practical analytical performance of the GN/GC electrode was examined by evaluating the selective detection of AE in natural aloe extracts and human urine samples with satisfied recovery. Therefore, the GN/GC electrode may hold great promise for fast, simple and sensitive detection and biomedical analysis of AE in complex matrices.

  6. Facile synthesis of glucose-sensitive chitosan-poly(vinyl alcohol) hydrogel: Drug release optimization and swelling properties.

    PubMed

    Abureesh, Mosab Ali; Oladipo, Akeem Adeyemi; Gazi, Mustafa

    2016-09-01

    The study describes the development of glucose-sensitive hydrogel and optimization of bovine serum albumin release profile from the hydrogel. To enhance the glucose sensitivity and improve the swelling behaviors of the hydrogel system, boric acid crosslinking, and freeze-thawing cycle techniques were used to prepare chitosan-poly(vinyl alcohol) hydrogel. The structure of the resultant hydrogel was confirmed by scanning electron microscopy and Fourier transform infrared spectroscopy. The experimental results revealed that the swelling of the hydrogel was influenced by the pH of the medium, and the hydrogel displayed explicit glucose-sensitivity under physiological conditions. The values of the diffusion exponent range between 0.34 and 0.44 and the diffusion of water into the gel system are assumed to be pseudo-Fickian in nature. Under optimized conditions, the cumulative Bovine serum albumin (BSA) drug releases ranged between 69.33±1.95% and 86.45±1.16% at 37°C in the presence of glucose and pH 7.4, respectively.

  7. Crosswise Model to Assess Sensitive Issues: A Study on Prevalence of Drug Abuse Among University Students of Iran

    PubMed Central

    Khosravi, Ahmad; Mousavi, Seyed Abbas; Chaman, Reza; Khosravi, Faride; Amiri, Mohammad; Shamsipour, Mansour

    2015-01-01

    Background: Precise assessment of the prevalence of illicit drug use, face various methodological challenges. Objectives: The current study aimed to investigate the prevalence of illicit drug use among students studying at Universities in Shahroud (Northeast of Iran) through crosswise method. Patients and Methods: Participants of this cross-sectional study were 1646 students at Universities in Shahroud. The data collection instrument was a questionnaire designed based on crosswise model (CM). Results: The results of the study showed that 19% of students used at least one kind of illicit drug and 14.9% used opium residue once in their life. Moreover, 3.5% of students used drug and 3% used opium residue during the last month; 40.3% of the students admitted that they fully understood the instruction of the questionnaire; 9.6% said that did not comprehend the instruction at all, and 38.1% believed they partly understood the instruction. The result showed that 33.7% of the students fully trusted, 39.8% partly trusted, and 18.4% poorly trusted this method. There was a significant relationship between comprehension level and trust in CM (P < 0.001). Conclusions: This method can be appropriate to estimate sensitive issues; however, lack of understanding the method or doubting the confidentiality of the responses can lead to bias in the results. That is to say, if the instructions are introduced better, the level of trusting the method will increase and accordingly more reliable responses can be obtained. More studies under controlled conditions are required to interpret the findings of the current study better. PMID:26405682

  8. Hyaluronic acid nanogels with enzyme-sensitive cross-linking group for drug delivery.

    PubMed

    Yang, Chenchen; Wang, Xin; Yao, Xikuang; Zhang, Yajun; Wu, Wei; Jiang, Xiqun

    2015-05-10

    A methacrylation strategy was employed to functionalize hyaluronic acid and prepare hyaluronic acid (HA) nanogels. Dynamic light scattering, zeta potential analyzer and electron microscopy were utilized to characterize the nanogels and their enzyme-degradability in vitro. It was found that these nanogels had a spherical morphology with the diameter of about 70nm, and negative surface potential. When doxorubicin (DOX) was loaded into the nanogels, the diameter decreased to approximately 50nm with a drug loading content of 16% and encapsulation efficiency of 62%. Cellular uptake examinations showed that HA nanogels could be preferentially internalized by two-dimensional (2D) cells and three-dimensional (3D) multicellular spheroids (MCs) which both overexpress CD44 receptor. Near-infrared fluorescence imaging, biodistribution and penetration examinations in tumor tissue indicated that the HA nanogels could efficiently accumulate and penetrate the tumor matrix. In vivo antitumor evaluation found that DOX-loaded HA nanogels exhibited a significantly superior antitumor effect.

  9. Preparation of a magnetic-field-sensitive hydrogel and preliminary study of its drug release behavior.

    PubMed

    Namdeo, Mini; Bajpai, S K; Kakkar, S

    2009-01-01

    The study describes the in situ formation of magnetite nanoparticles within a swollen polyacrylamide hydrogel. The average diameter of nanoparticles, as determined by TEM analysis, was found to be nearly 12.5 nm. In XRD analysis the characteristic peaks, observed at d = 3.07, 2.78, 2.64, 2.53, 2.32 and 2.03, also confirmed the formation of magnetite within the polymer network. The percent swelling of magnetite-loaded gel in physiological fluid was observed to decrease with increasing amount of magnetite in the gel. Moreover, the percent swelling increased from 140 to 254% as the strength of the applied magnetic field increased from 500 to 2500 Oe. Finally, the model drug, vitamin B(2), loaded magnetic gels showed relatively slower release in the presence of an applied magnetic field.

  10. In vitro studies on the sensitivity of local Entamoeba histolytica to anti-amoebic drugs.

    PubMed

    Chintana, T; Sucharit, P; Mahakittikun, V; Siripanth, C; Suphadtanaphongs, W

    1986-12-01

    The in vitro activity of drugs, namely dehydroemetine, ornidazole, metronidazole and tinidazole were determined against the locally isolated strains of E. histolytica in Thailand. The test was performed in liquid monophasic medium, i.e. liver marmite serum medium. In all, locally isolated strains from thirty hosts studied, the minimal inhibitory concentration (MIC) for dehydroemetine ranged from 0.125 to 1 microgram/ml, ornidazole ranged from 0.0625 to 0.25 microgram/ml, metronidazole ranged from 0.0625 to 0.125 microgram/ml, and tinidazole ranged from 0.0625 microgram/ml to 0.25 microgram/ml. The MIC of dehydroemetine was significantly different from ornidazole, metronidazole and tinidazole. Metronidazole was superior to that of dehydroemetine but was not significantly different among ornidazole, metronidazole and tinidazole.

  11. Mock juror sensitivity to forensic evidence in drug facilitated sexual assaults.

    PubMed

    Schuller, Regina A; Ryan, Alison; Krauss, Daniel; Jenkins, Gwen

    2013-01-01

    Mock jurors' reactions to variations in the quality of toxicological evidence regarding the presence of drugs in a sexual assault trial were examined. In Study 1, participants received a trial summary in which a negative test result, a negative test result plus expert testimony, or no test result was presented. The time taken by the complainant to report the alleged sexual assault was manipulated. The negative test result influenced participants' judgments, but this effect was minimized by the presence of expert testimony. The complainant's delay in reporting had little impact on judgments. In Study 2, complainant time to report was again manipulated along with the outcome of the test result (negative finding and no result). Results revealed that men were less conviction prone when the negative test result was obtained early as opposed to late. In contrast, when the test result was unavailable, men were more conviction prone when the complainant reported late as oppose to early.

  12. PEG-SS-PPS: reduction-sensitive disulfide block copolymer vesicles for intracellular drug delivery.

    PubMed

    Cerritelli, Simona; Velluto, Diana; Hubbell, Jeffrey A

    2007-06-01

    Under appropriate conditions, block copolymeric macroamphiphiles will self-assemble in water to form vesicles, referred to as polymersomes. We report here polymersomes that can protect biomolecules in the extracellular environment, are taken up by endocytosis, and then suddenly burst within the early endosome, releasing their contents prior to exposure to the harsh conditions encountered after lysosomal fusion. Specifically, block copolymers of the hydrophile poly(ethylene glycol) (PEG) and the hydrophobe poly(propylene sulfide) (PPS) were synthesized with an intervening disulfide, PEG17-SS-PPS30. Polymersomes formed from this block copolymer were demonstrated to disrupt in the presence of intracellular concentrations of cysteine. In cellular experiments, uptake, disruption, and release were observed within 10 min of exposure to cells, well within the time frame of the early endosome of endolysosomal processing. This system may be useful in cytoplasmic delivery of biomolecular drugs such as peptides, proteins, oligonucleotides, and DNA.

  13. Inhibition of demethylase KDM6B sensitizes diffuse large B-cell lymphoma to chemotherapeutic drugs

    PubMed Central

    Mathur, Rohit; Sehgal, Lalit; Havranek, Ondrej; Köhrer, Stefan; Khashab, Tamer; Jain, Neeraj; Burger, Jan A.; Neelapu, Sattva S.; Davis, R. Eric; Samaniego, Felipe

    2017-01-01

    Histone methylation and demethylation regulate B-cell development, and their deregulation correlates with tumor chemoresistance in diffuse large B-cell lymphoma, limiting cure rates. Since histone methylation status correlates with disease aggressiveness and relapse, we investigated the therapeutic potential of inhibiting histone 3 Lys27 demethylase KDM6B, in vitro, using the small molecule inhibitor GSK-J4. KDM6B is overexpressed in the germinal center B-cell subtype of diffuse large B-cell lymphoma, and higher KDM6B levels are associated with worse survival in patients with diffuse large B-cell lymphoma treated with R-CHOP. GSK-J4-induced apoptosis was observed in five (SU-DHL-6, OCI-Ly1, Toledo, OCI-Ly8, SU-DHL-8) out of nine germinal center B-cell diffuse large B-cell lymphoma cell lines. Treatment with GSK-J4 predominantly resulted in downregulation of B-cell receptor signaling and BCL6. Cell lines expressing high BCL6 levels or CREBBP/EP300 mutations were sensitive to GSK-J4. Our results suggest that B-cell receptor-dependent downregulation of BCL6 is responsible for GSK-J4-induced cytotoxicity. Furthermore, GSK-J4-mediated inhibition of KDM6B sensitizes germinal center B-cell diffuse large B-cell lymphoma cells to chemotherapy agents that are currently utilized in treatment regimens for diffuse large B-cell lymphoma. PMID:27742770

  14. Drugs.

    ERIC Educational Resources Information Center

    Hurst, Hunter, Ed.; And Others

    1984-01-01

    This document contains the third volume of "Today's Delinquent," an annual publication of the National Center for Juvenile Justice. This volume deals with the issue of drugs and includes articles by leading authorities in delinquency and substance abuse who share their views on causes and cures for the drug problem among youth in this country.…

  15. Assessment of the Worldwide Antimalarial Resistance Network Standardized Procedure for In Vitro Malaria Drug Sensitivity Testing Using SYBR Green Assay for Field Samples with Various Initial Parasitemia Levels

    PubMed Central

    Cheruiyot, Agnes C.; Auschwitz, Jennifer M.; Lee, Patricia J.; Yeda, Redemptah A.; Okello, Charles O.; Leed, Susan E.; Talwar, Mayank; Murthy, Tushar; Gaona, Heather W.; Hickman, Mark R.; Akala, Hoseah M.; Kamau, Edwin

    2016-01-01

    The malaria SYBR green assay, which is used to profile in vitro drug susceptibility of Plasmodium falciparum, is a reliable drug screening and surveillance tool. Malaria field surveillance efforts provide isolates with various low levels of parasitemia. To be advantageous, malaria drug sensitivity assays should perform reproducibly among various starting parasitemia levels rather than at one fixed initial value. We examined the SYBR green assay standardized procedure developed by the Worldwide Antimalarial Resistance Network (WWARN) for its sensitivity and ability to accurately determine the drug concentration that inhibits parasite growth by 50% (IC50) in samples with a range of initial parasitemia levels. The initial sensitivity determination of the WWARN procedure yielded a detection limit of 0.019% parasitemia. P. falciparum laboratory strains and field isolates with various levels of initial parasitemia were then subjected to a range of doses of common antimalarials. The IC50s were comparable for laboratory strains with between 0.0375% and 0.6% parasitemia and for field isolates with between 0.075% and 0.6% parasitemia for all drugs tested. Furthermore, assay quality (Z′) analysis indicated that the WWARN procedure displays high robustness, allowing for drug testing of malaria field samples within the derived range of initial parasitemia. The use of the WWARN procedure should allow for the inclusion of more malaria field samples in malaria drug sensitivity screens that would have otherwise been excluded due to low initial parasitemia levels. PMID:26856829

  16. Sensitive detection of drug vapors using an ion funnel interface for secondary electrospray ionization mass spectrometry.

    PubMed

    Meier, Lukas; Berchtold, Christian; Schmid, Stefan; Zenobi, Renato

    2012-05-01

    In this study, we use an ion funnel (IF) at ambient pressure to enhance the sensitivity of secondary electrospray ionization (SESI). Atenolol, salbutamol and cocaine as test compounds are delivered to the SESI interface in the gas phase and are charged with three nano electrosprays. In our experiments, we show that the compounds can be detected at concentrations in the low pptv range, which is an increase of two orders of magnitude compared with the results without the IF. With a standard SESI interface, the compounds could not be detected at all. With the use of the SESI IF interface for the headspace analysis of bananas and limes, we can detect many more compounds and at higher intensities than with a standard SESI interface.

  17. Selection of Parasites with Diminished Drug Sensitivity by Amodiaquine-Containing Antimalarial Regimens in Uganda

    PubMed Central

    Nawaz, Fatima; Nsobya, Samuel L.; Kiggundu, Moses; Joloba, Moses; Rosenthal, Philip J.

    2009-01-01

    Background Amodiaquine (AQ) is paired with artesunate (AS) or sulfadoxine-pyrimethamine (SP) in recommended antimalarial regimens. It is unclear how readily AQ resistance will be selected with combination chemotherapy. Methods We collected 61 Plasmodium falciparum samples from a cohort of Ugandan children randomized to treatment with AQ/SP, AS/AQ, or artemether-lumefantrine (AL) for uncomplicated malaria. In vitro sensitivity to monodesethylamodiaquine (MDAQ) was measured with a histidine rich protein-2-based ELISA, and potential resistance-mediating polymorphisms pfmdr-1were evaluated. Results Parasites from subjects previously treated with AQ/SP or AS/AQ within 12 weeks were less sensitive to MDAQ (n=18; mean IC50 62.9 nM; range 12.7–158.3 nM) than parasites from those not treated within 12 weeks (n=43; mean IC50 37.5 nM; range 6.3–184.7 nM; p=0.0085) or only those in the treatment arm that did not contain AQ (n=20; mean IC50 28.8 nM; range 6.3–121.8 nM; p=0.0042). The proportion of strains with polymorphisms expected to mediate diminished response to AQ (pfmdr-1 86Y and 1246Y) increased after prior AQ therapy, although differences were not significant. Conclusions Prior therapy selected for diminished response to MDAQ, suggesting that AQ-containing regimens may rapidly lose efficacy in Africa. The mechanism of diminished MDAQ response is not fully explained by known mutations in pfmdr-1. PMID:19905933

  18. PES1 regulates sensitivity of colorectal cancer cells to anticancer drugs

    SciTech Connect

    Xie, Wei; Qu, Like; Meng, Lin; Liu, Caiyun; Wu, Jian; Shou, Chengchao

    2013-02-15

    Highlights: ► PES1 was overexpressed in diverse cancer cell lines. ► PES1-ablation enhances DNA damage response by decreasing DNA repair. ► PES1-ablation increases the sensitivity of HCT116 cells to chemotherapeutic agents. ► PES1-ablation is associated with diminished nuclear entry of RAD51. -- Abstract: PES1 (also known as Pescadillo), a nucleolar protein, was involved in biogenesis of ribosomal RNA. Up-regulation of PES1 has been documented in some human cancers, indicating that PES1 may play some crucial roles in tumorigenesis. In our previous study, it was found that silencing of PES1 resulted in decreased proliferation of colorectal cancer cells. We also noticed that depletion of PES1 altered expression profiles of diverse genes. In the present study, we validated the expression changes of a subset of genotoxic stress-related genes in PES1-silenced HCT116 cells by quantitative RT-PCR. The steady and etoposide-induced phosphorylated H2AX (γ-H2AX) were higher in PES1-silenced cells than in control cells. Besides, etoposide-induced γ-H2AX persisted longer in PES1-silenced cells after removing the etoposide. Next, results of comet assay revealed decreased DNA repair after PES1-ablation. PES1-ablated cells were more sensitive to chemotherapeutic agents, which could be reversed by reconstitution with exogenous PES1. Furthermore, deletion of PES1 diminished steady and DNA damage-induced levels of nuclear RAD51. Our results uncover a potential role of PES1 in chemoresistance by regulating DNA damage response in colorectal cancer cells.

  19. The drug sensitivity and transmission dynamics of human malaria on Nias Island, North Sumatra, Indonesia.

    PubMed

    Fryauff, D J; Leksana, B; Masbar, S; Wiady, I; Sismadi, P; Susanti, A I; Nagesha, H S; Syafruddin; Atmosoedjono, S; Bangs, M J; Baird, J K

    2002-07-01

    Nias Island, off the north-western coast of Sumatra, Indonesia, was one of the first locations in which chloroquine-resistant Plasmodium vivax malaria was reported. This resistance is of particular concern because its ancient megalithic culture and the outstanding surfing conditions make the island a popular tourist destination. International travel to and from the island could rapidly spread chloroquine-resistant strains of P. vivax across the planet. The threat posed by such strains, locally and internationally, has led to the routine and periodic re-assessment of the efficacy of antimalarial drugs and transmission potential on the island. Active case detection identified malaria in 124 (17%) of 710 local residents whereas passive case detection, at the central health clinic, confirmed malaria in 77 (44%) of 173 cases of presumed 'clinical malaria'. Informed consenting volunteers who had malarial parasitaemias were treated, according to the Indonesian Ministry of Health's recommendations, with sulfadoxine-pyrimethamine (SP) on day 0 (for P. falciparum) or with chloroquine (CQ) on days 0, 1 and 2 (for P. vivax). Each volunteer was then monitored for clinical and parasite response until day 28. Recurrent parasitaemia by day 28 treatment was seen in 29 (83%) of the 35 P. falciparum cases given SP (14, 11 and four cases showing RI, RII and RIII resistance, respectively). Recurrent parasitaemia was also observed, between day 11 and day 21, in six (21%) of the 28 P. vivax cases given CQ. Although the results of quantitative analysis confirmed only low prevalences of CQ-resistant P. vivax malaria, the prevalence of SP resistance among the P. falciparum cases was among the highest seen in Indonesia. When the parasites present in the volunteers with P. falciparum infections were genotyped, mutations associated with pyrimethamine resistance were found at high frequency in the dhfr gene but there was no evidence of selection for sulfadoxine resistance in the dhps gene

  20. B-cell receptor triggers drug sensitivity of primary CLL cells by controlling glucosylation of ceramides.

    PubMed

    Schwamb, Janine; Feldhaus, Valeska; Baumann, Michael; Patz, Michaela; Brodesser, Susanne; Brinker, Reinhild; Claasen, Julia; Pallasch, Christian P; Hallek, Michael; Wendtner, Clemens-Martin; Frenzel, Lukas P

    2012-11-08

    Survival of chronic lymphocytic leukemia (CLL) cells is triggered by several stimuli, such as the B-cell receptor (BCR), CD40 ligand (CD40L), or interleukin-4 (IL-4). We identified that these stimuli regulate apoptosis resistance by modulating sphingolipid metabolism. Applying liquid chromatography electrospray ionization tandem mass spectrometry, we revealed a significant decrease of proapoptotic ceramide in BCR/IL-4/CD40L-stimulated primary CLL cells compared with untreated controls. Antiapoptotic glucosylceramide levels were significantly increased after BCR cross-linking. We identified BCR engagement to catalyze the crucial modification of ceramide to glucosylceramide via UDP-glucose ceramide glucosyltransferase (UGCG). Besides specific UGCG inhibitors, our data demonstrate that IgM-mediated UGCG expression was inhibited by the novel and highly effective PI3Kδ and BTK inhibitors CAL-101 and PCI-32765, which reverted IgM-induced resistance toward apoptosis of CLL cells. Sphingolipids were recently shown to be crucial for mediation of apoptosis via mitochondria. Our data reveal ABT-737, a mitochondria-targeting drug, as interesting candidate partner for PI3Kδ and BTK inhibition, resulting in synergistic apoptosis, even under protection by the BCR. In summary, we identified the mode of action of novel kinase inhibitors CAL-101 and PCI-32765 by controlling the UGCG-mediated ceramide/glucosylceramide equilibrium as a downstream molecular switch of BCR signaling, also providing novel targeted treatment options beyond current chemotherapy-based regimens.

  1. Application of firefly luciferase assay for adenosine triphosphate (ATP) to antimicrobial drug sensitivity testing

    NASA Technical Reports Server (NTRS)

    Picciolo, G. L.; Tuttle, S. A.; Schrock, C. G.; Deming, J. W.; Barza, M. J.; Wienstein, L.; Chappelle, E. W.

    1977-01-01

    The development of a rapid method for determining microbial susceptibilities to antibiotics using the firefly luciferase assay for adenosine triphosphate (ATP) is documented. The reduction of bacterial ATP by an antimicrobial agent was determined to be a valid measure of drug effect in most cases. The effect of 12 antibiotics on 8 different bacterial species gave a 94 percent correlation with the standard Kirby-Buer-Agar disc diffusion method. A 93 percent correlation was obtained when the ATP assay method was applied directly to 50 urine specimens from patients with urinary tract infections. Urine samples were centrifuged first to that bacterial pellets could be suspended in broth. No primary isolation or subculturing was required. Mixed cultures in which one species was predominant gave accurate results for the most abundant organism. Since the method is based on an increase in bacterial ATP with time, the presence of leukocytes did not interfere with the interpretation of results. Both the incubation procedure and the ATP assays are compatible with automation.

  2. Synthetic Organotellurium Compounds Sensitize Drug-Resistant Candida albicans Clinical Isolates to Fluconazole.

    PubMed

    Reis de Sá, L F; Toledo, F T; Gonçalves, A C; Sousa, B A; Dos Santos, A A; Brasil, P F; Duarte da Silva, V A; Tessis, A C; Ramos, J A; Carvalho, M A; Lamping, E; Ferreira-Pereira, A

    2017-01-01

    Invasive Candida albicans infections are a serious health threat for immunocompromised individuals. Fluconazole is most commonly used to treat these infections, but resistance due to the overexpression of multidrug efflux pumps is of grave concern. This study evaluated the ability of five synthetic organotellurium compounds to reverse the fluconazole resistance of C. albicans clinical isolates. Compounds 1 to 4, at <10 μg/ml, ameliorated the fluconazole resistance of Saccharomyces cerevisiae strains overexpressing the major C. albicans multidrug efflux pumps Cdr1p and Mdr1p, whereas compound 5 only sensitized Mdr1p-overexpressing strains to fluconazole. Compounds 1 to 4 also inhibited efflux of the fluorescent substrate rhodamine 6G and the ATPase activity of Cdr1p, whereas all five of compounds 1 to 5 inhibited Nile red efflux by Mdr1p. Interestingly, all five compounds demonstrated synergy with fluconazole against efflux pump-overexpressing fluconazole-resistant C. albicans clinical isolates, isolate 95-142 overexpressing CDR1 and CDR2, isolate 96-25 overexpressing MDR1 and ERG11, and isolate 12-99 overexpressing CDR1, CDR2, MDR1, and ERG11 Overall, organotellurium compounds 1 and 2 were the most promising fluconazole chemosensitizers of fluconazole-resistant C. albicans isolates. Our data suggest that these novel organotellurium compounds inhibit pump efflux by two very important and distinct families of fungal multidrug efflux pumps: the ATP-binding cassette transporter Cdr1p and the major facilitator superfamily transporter Mdr1p.

  3. Sirtuin 3 enhanced drug sensitivity of human hepatoma cells through glutathione S-transferase pi 1/JNK signaling pathway

    PubMed Central

    Cai, Xue-Fei; Zhang, Wen-Lu; Ren, Ji-Hua; Zhou, Li; Chen, Xiang; Chen, Ke; Li, Wan-Yu; Liu, Bo; Yang, Qiu-Xia; Cheng, Sheng-Tao; Huang, Li-Xia; Huang, Ai-Long; Chen, Juan

    2016-01-01

    SIRT3, a class III histone deacetylase, has been implicated in various cancers as a novel therapeutic target. In hepatocellular carcinoma (HCC), we previously reported that SIRT3 induced cell apoptosis by regulating GSK-3β/Bax signaling pathway. Downregulation of SIRT3 in HCC cells facilitates tumor cell survival. In this study, we found that chemotherapeutic agents (doxorubicin, cisplatin and epirubicin) and sorafenib treatment downregulated SIRT3 mRNA and protein levels in three HCC cell lines. MTS assay found that SIRT3 overexpression sensitized liver cancer cells to chemotherapeutic agents and sorafenib in SMMC-7721, Huh-7 and PLC/PRF/5 cell lines. Moreover, SIRT3 overexpression promoted chemotherapeutic agents-induced or sorafenib-induced apoptosis as evidenced by flow cytometry, enhanced PARP cleavage and enhanced Caspase-9 cleavage in three HCC cells. In contrast, SIRT3 silencing increased drug resistance of HCC cells to chemotherapeutic agents. Mechanistic study found that SIRT3 downregulated the mRNA and protein levels of glutathione S-transferase pi 1 (GSTP1), which is a member of phase II detoxification enzymes families involved in metabolizing for chemotherapeutic agents. Moreover, SIRT3 decreased the amount of GSTP1 that was associated with JNK, which finally contributed the activation of JNK activity and activation of downstream target c-Jun and Bim. Importantly, GSTP1 overexpression or JNK inhibitor abolished SIRT3-induced apoptosis in HCC cells exposed to chemotherapeutic agents. Finally, there was a negative correlation between SIRT3 expression and GSTP1 expression in human HCC tissues. Together, our findings revealed SIRT3 could enhance the drug sensitivity of HCC cells to an array of chemotherapeutic agents. SIRT3 may serve as a potential target for improving the chemosensitivity of HCC patients. PMID:27367026

  4. Injections, Cocktails and Diviners: Therapeutic Flexibility in the Context of Malaria Elimination and Drug Resistance in Northeast Cambodia

    PubMed Central

    Gryseels, Charlotte; Uk, Sambunny; Erhart, Annette; Gerrets, René; Sluydts, Vincent; Durnez, Lies; Muela Ribera, Joan; Hausmann Muela, Susanna; Menard, Didier; Heng, Somony; Sochantha, Tho; D’Alessandro, Umberto; Coosemans, Marc; Peeters Grietens, Koen

    2013-01-01

    Background Adherence to effective malaria medication is extremely important in the context of Cambodia’s elimination targets and drug resistance containment. Although the public sector health facilities are accessible to the local ethnic minorities of Ratanakiri province (Northeast Cambodia), their illness itineraries often lead them to private pharmacies selling “cocktails” and artemether injections, or to local diviners prescribing animal sacrifices to appease the spirits. Methods The research design consisted of a mixed methods study, combining qualitative (in-depth interviews and participant observation) and quantitative methods (household and cross-sectional survey). Results Three broad options for malaria treatment were identified: i) the public sector; ii) the private sector; iii) traditional treatment based on divination and ceremonial sacrifice. Treatment choice was influenced by the availability of treatment and provider, perceived side effects and efficacy of treatments, perceived etiology of symptoms, and patient-health provider encounters. Moreover, treatment paths proved to be highly flexible, changing mostly in relation to the perceived efficacy of a chosen treatment. Conclusions Despite good availability of anti-malarial treatment in the public health sector, attendance remained low due to both structural and human behavioral factors. The common use and under-dosage of anti-malaria monotherapy in the private sector (single-dose injections, single-day drug cocktails) represents a threat not only for individual case management, but also for the regional plan of drug resistance containment and malaria elimination. PMID:24244678

  5. Assessment of the Worldwide Antimalarial Resistance Network Standardized Procedure for In Vitro Malaria Drug Sensitivity Testing Using SYBR Green Assay for Field Samples with Various Initial Parasitemia Levels.

    PubMed

    Cheruiyot, Agnes C; Auschwitz, Jennifer M; Lee, Patricia J; Yeda, Redemptah A; Okello, Charles O; Leed, Susan E; Talwar, Mayank; Murthy, Tushar; Gaona, Heather W; Hickman, Mark R; Akala, Hoseah M; Kamau, Edwin; Johnson, Jacob D

    2016-04-01

    The malaria SYBR green assay, which is used to profilein vitrodrug susceptibility ofPlasmodium falciparum, is a reliable drug screening and surveillance tool. Malaria field surveillance efforts provide isolates with various low levels of parasitemia. To be advantageous, malaria drug sensitivity assays should perform reproducibly among various starting parasitemia levels rather than at one fixed initial value. We examined the SYBR green assay standardized procedure developed by the Worldwide Antimalarial Resistance Network (WWARN) for its sensitivity and ability to accurately determine the drug concentration that inhibits parasite growth by 50% (IC50) in samples with a range of initial parasitemia levels. The initial sensitivity determination of the WWARN procedure yielded a detection limit of 0.019% parasitemia.P. falciparumlaboratory strains and field isolates with various levels of initial parasitemia were then subjected to a range of doses of common antimalarials. The IC50s were comparable for laboratory strains with between 0.0375% and 0.6% parasitemia and for field isolates with between 0.075% and 0.6% parasitemia for all drugs tested. Furthermore, assay quality (Z') analysis indicated that the WWARN procedure displays high robustness, allowing for drug testing of malaria field samples within the derived range of initial parasitemia. The use of the WWARN procedure should allow for the inclusion of more malaria field samples in malaria drug sensitivity screens that would have otherwise been excluded due to low initial parasitemia levels.

  6. pH-sensitive nanocargo based on smart polymer functionalized graphene oxide for site-specific drug delivery.

    PubMed

    Kavitha, Thangavelu; Abdi, Syed Izhar Haider; Park, Soo-Young

    2013-04-14

    Graphene oxide (GO) was functionalized covalently with pH-sensitive poly(2-(diethylamino) ethyl methacrylate) (PDEA) by surface-initiated in situ atom transfer radical polymerization. The structure of the PDEA-grafted GO (GO-PDEA) were examined by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis and atomic force microscopy. The grafted PDEA endowed the GO sheets with good solubility and stability in physiological solutions. Simple physisorption by π-π stacking and hydrophobic interactions on GO-PDEA can be used to load camptothecin (CPT), a widely used water-insoluble cancer drug. The loaded CPT was released only at the lower (acidic) pH normally found in a tumor environment but not in basic and neutral pH. GO-PDEA did not show practical toxicity to N2a cancer cells but the GO-PDEA-CPT complex exhibited high potency in killing N2a cancer cells in vitro. These results suggest that the GO-PDEA nanocargo carrier might be a promising material for site-specific anticancer drug delivery and controlled release.

  7. Binding-pocket and lid-region substitutions render human STING sensitive to the species-specific drug DMXAA.

    PubMed

    Gao, Pu; Zillinger, Thomas; Wang, Weiyi; Ascano, Manuel; Dai, Peihong; Hartmann, Gunther; Tuschl, Thomas; Deng, Liang; Barchet, Winfried; Patel, Dinshaw J

    2014-09-25

    The drug DMXAA (5,6-dimethylxanthenone-4-acetic acid) showed therapeutic promise against solid tumors in mouse models but subsequently failed in human clinical trials. DMXAA was later discovered to activate mouse, but not human, STING, an adaptor protein in the cyclic dinucleotide cGAMP-mediated signaling pathway, inducing type I interferon expression. To facilitate the development of compounds that target human STING, we combined structural, biophysical, and cellular assays to study mouse and human chimeric proteins and their interaction with DMXAA. We identified a single substitution (G230I) that enables a DMXAA-induced conformational transition of hSTING from an inactive "open" to an active "closed" state. We also identified a substitution within the binding pocket (Q266I) that cooperates with G230I and the previously identified S162A binding-pocket point substitution, rendering hSTING highly sensitive to DMXAA. These findings should facilitate the reciprocal engineering of DMXAA analogs that bind and stimulate wild-type hSTING and their exploitation for vaccine-adjuvant and anticancer drug development.

  8. Tumor-targeting, pH-sensitive nanoparticles for docetaxel delivery to drug-resistant cancer cells

    PubMed Central

    Tran, Tuan Hiep; Ramasamy, Thiruganesh; Choi, Ju Yeon; Nguyen, Hanh Thuy; Pham, Thanh Tung; Jeong, Jee-Heon; Ku, Sae Kwang; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2015-01-01

    The attachment of polyethylene glycol (PEG) increases the circulation time of drug-containing nanoparticles; however, this also negatively affects cellular uptake. To overcome this problem, unique lipid polymer hybrid (LPH) nanoparticles were developed with a pH-responsive PEG layer that detached prior to cell uptake. Docetaxel (DTX) was incorporated into the lipid core of the nanoparticles, which was then shielded with the pH-responsive block co-polymer polyethylene glycol-b-polyaspartic acid (PEG-b-PAsp) using a modified emulsion method. The optimized LPH nanoparticles were ~200 nm and had a narrow size distribution. Drug release from DTX-loaded LPH (DTX-LPH) nanoparticles was pH-sensitive, which is beneficial for tumor targeting. More importantly, DTX-LPH nanoparticles were able to effectively induce apoptosis in cancer cells. The negative surface charge and PEG shell of vehicle remarkably enhanced the blood circulation and physiological activity of DTX-LPH nanoparticles compared with that of free DTX. The nanoparticles were also found to reduce the size of tumors in tumor-bearing xenograft mice. The in vivo anticancer effect of DTX-LPH nanoparticles was further confirmed by the elevated levels of caspase-3 and poly ADP ribose polymerase found in the tumors after treatment. Thus, the results suggest that this novel LPH system could be an effective new treatment for cancer. PMID:26346426

  9. Drug co-loading and pH-sensitive release core-shell nanoparticles via layer-by-layer assembly.

    PubMed

    Tian, Liang; Yang, Jing; Ji, Feng; Liu, Yuxi; Yao, Fanglian

    2014-01-01

    Multifunctional core-shell nanoparticles are widely used for biomedical and catalytic applications. In this work, bilayers of chitosan (Cs) and phosphorylated polyvinyl alcohol (PPVA) were sequentially deposited on 3-Aminopropyltri-ethoxysilane-modified SiO2 nanoparticles via layer-by-layer electrostatic self-assembly. The good spherical shape and size distribution were observed by DLS and transmission electron microscope analysis. 7-Hydroxycoumarin (7-HC) and rhodamine B (RhB) as model drugs were loaded in the core and shell of the nanoparticles separately. Confocal laser scanning microscopy shows the core-shell structure of HC-SiO2(PPVA/Cs)n-RhB nanoparticles and the embedded location of 7-HC and RhB. The pH-sensitive release investigation of RhB indicates that the release profiles of RhB from HC-SiO2(PPVA/Cs)3PPVA-RhB core-shell nanoparticles are totally different at pH values of 2.0, 7.4, and 9.2. These results predict that the multifunctional nanoparticle SiO2(PPVA/Cs)n has a great potential for drug delivery.

  10. Promising survival for patients with glioblastoma multiforme treated with individualised chemotherapy based on in vitro drug sensitivity testing.

    PubMed

    Iwadate, Y; Fujimoto, S; Namba, H; Yamaura, A

    2003-11-17

    We retrospectively investigated the efficacy and feasibility of individualised chemotherapy based on in vitro drug sensitivity testing (DST) for patients with glioblastoma multiforme. A total of 40 consecutive patients with glioblastoma multiforme (GM) were enrolled into this study between January 1995 and December 2000. The flow cytometric (FCM) detection of apoptosis was used to determine the in vitro sensitivity of tumour cells obtained at surgery to 30 different kinds of anticancer agents. From the results of FCM assay, an in vitro best regimen was prospectively selected. All the patients concurrently received the individualised chemotherapy with the in vitro best regimen and 60 Gy of conventional radiation therapy. Of the 31 assessable patients, eight patients (26%) achieved partial response, and 20 patients (65%) had stable disease. The median survival time was 20.5 months. The individualised chemotherapy based on in vitro DST was associated with favourable survival time for the patients with GM compared with the reported results of conventional therapy regimens. The present result suggests that the currently available anticancer agents could be effective against GM when used in individualised chemotherapy.

  11. Low molecular-weight chitosan as a pH-sensitive stealth coating for tumor-specific drug delivery

    PubMed Central

    Amoozgar, Zohreh; Park, Joonyoung; Lin, Qingnuo; Yeo, Yoon

    2012-01-01

    When a nanoparticle is developed for systemic application, its surface is typically protected by polyethylene glycol (PEG) to help their prolonged circulation and evasion of immune clearance. On the other hand, PEG can interfere with interactions between nanocarriers and target cells and negatively influence the therapeutic outcomes. To overcome this challenge, we propose low molecular-weight chitosan (LMWC) as an alternative surface coating, which can protect the nanomedicine in neutral pH but allow cellular interactions in weakly acidic pH of tumors. LMWCs with a molecular weight of 2–4 kDa, 4–6.5 kDa, and 11–22 kDa were produced by hydrogen peroxide digestion and covalently conjugated with poly(lactic-co-glycolic acid) (PLGA). Nanoparticles created with PLGA-LMWC conjugates showed pH-sensitive cell interactions, which enabled specific drug delivery to cells in a weakly acidic environment. The hydrophilic LMWC layer reduced opsonization and phagocytic uptake. These properties qualify LMWCs as a promising biomaterial for pH-sensitive stealth coating. PMID:22489704

  12. A Drug-Sensitized Zebrafish Screen Identifies Multiple Genes, Including GINS3, as Regulators of Myocardial Repolarization

    PubMed Central

    Milan, David J.; Kim, Albert M.; Winterfield, Jeffrey R.; Jones, Ian L.; Pfeufer, Arne; Sanna, Serena; Arking, Dan E.; Amsterdam, Adam H.; Sabeh, Khaled M.; Mably, John D.; Rosenbaum, David S.; Peterson, Randall T.; Chakravarti, Aravinda; Kääb, Stefan; Roden, Dan M.; MacRae, Calum A.

    2009-01-01

    Background Cardiac repolarization, the process by which cardiomyocytes return to their resting potential after each beat, is a highly regulated process that is critical for heart rhythm stability. Perturbations of cardiac repolarization increase the risk for life-threatening arrhythmias and sudden cardiac death. While genetic studies of familial long QT syndromes have uncovered several key genes in cardiac repolarization, the major heritable contribution to this trait remains unexplained. Identification of additional genes may lead to a better understanding of the underlying biology, aid in identification of patients at risk for sudden death, and potentially enable new treatments for susceptible individuals. Methods and Results We extended and refined a zebrafish model of cardiac repolarization by using fluorescent reporters of transmembrane potential. We then conducted a drug-sensitized genetic screen in zebrafish, identifying 15 genes, including GINS3, that affect cardiac repolarization. Testing these genes for human relevance in two concurrently completed genome wide association studies revealed that the human GINS3 ortholog is located in the 16q21 locus which is strongly associated with QT interval. Conclusions This sensitized zebrafish screen identified 15 novel myocardial repolarization genes. Among these genes is GINS3, the human ortholog of which is a major locus in two concurrent human genome wide association studies of QT interval. These results reveal a novel network of genes that regulate cardiac repolarization. PMID:19652097

  13. Effects of the Selective MPS1 Inhibitor MPS1-IN-3 on Glioblastoma Sensitivity to Antimitotic Drugs

    PubMed Central

    2013-01-01

    sensitizing glioblastoma cells to antimitotic drugs. PMID:23940287

  14. Stepwise targeted drug delivery to liver cancer cells for enhanced therapeutic efficacy by galactose-grafted, ultra-pH-sensitive micelles.

    PubMed

    Yan, Guoqing; Wang, Jun; Hu, Liefeng; Wang, Xin; Yang, Guanqing; Fu, Shengxiang; Cheng, Xu; Zhang, Panpan; Tang, Rupei

    2017-03-15

    To promote drug accumulation and cell-killing ability at tumor tissue, we have prepared a stepwise targeted drug delivery system that can remain stealthy and long-circulating in the blood vessels, improve drug retention at extracellular stimuli, enhance cellular uptake through special targeting ligands, and then achieve rapid drug release to improve toxicity to tumor cells at intracellular stimuli. Herein, galactose-grafted, ultra-pH-sensitive drug carriers (POEAd-g-LA-DOX micelles), which could respond to both extracellular and intracellular pH, and combine with galactose-receptors in cell membrane, were constructed by a facile method, therefore achieving: (i) remaining stable at pH 7.4; (ii) responding to tumoral extracellular pH following gradually larger nanoparticles (NPs); (iii) conjugating receptors in the cell membrane of liver cancer through surface galactose-ligands of micelles; (iv) being sensitive to tumoral intracellular pH following further swelling for rapid drug release. In vitro cytotoxicity and cellular uptake measurement showed that POEAd-g-LA20-DOX micelle was more easily internalized and more toxic effect on tumor cells than free DOX. Moreover, in vivo biodistribution and tumor inhibition examinations demonstrated that POEAd-g-LA20-DOX formulation had more superior efficacy to significantly enhance drug accumulation in tumor, and then restrain tumor growth while decreasing drug concentration in heart.

  15. Targeting of Wnt/β-Catenin by Anthelmintic Drug Pyrvinium Enhances Sensitivity of Ovarian Cancer Cells to Chemotherapy

    PubMed Central

    Zhang, Chongyuan; Zhang, Zhenge; Zhang, Shuirong; Wang, Wenrong; Hu, Ping

    2017-01-01

    Background Aberrant activation of Wnt/β-catenin has been shown to promote ovarian cancer proliferation and chemoresistance. Pyrvinium, an FDA-approved anthelmintic drug, has been identified as a potent Wnt inhibitor. Pyrvinium may sensitize ovarian cancer cells to chemotherapy. Material/Methods The effect of pyrvinium alone and its combination with paclitaxel in ovarian cancer was investigated using an in vitro culture system and in vivo xenograft models. The mechanisms of its action were also analyzed, focusing on the Wnt/β-catenin pathway. Results Pyrvinium inhibited growth and induced apoptosis of paclitaxel- and cisplatin-resistant epithelial ovarian cancer cell lines A2278/PTX and SK-OV-3. Its combination with paclitaxel was synergistic in targeting ovarian cancer cells in vitro. In 3 independent ovarian xenograft mouse models, pyrvinium alone inhibited tumor growth. More importantly, we observed significant inhibition of tumor growth throughout the treatment when using pyrvinium and paclitaxel combined. Mechanistically, pyrvinium increased the Wnt-negative regulator axin and decreased the β-catenin levels in ovarian cancer cells. In addition, pyrvinium suppressed Wnt/β-catenin-mediated transcription, as shown by the decreased mRNA levels of MYC, cyclin D, and BCL-9. In contrast, the inhibitory effects of pyrvinium were reversed by β-catenin stabilization or overexpression, demonstrating that pyrvinium acted on ovarian cancer cells via targeting the Wnt/β-catenin signaling pathway. Conclusions We demonstrated that the anthelmintic drug pyrvinium targets ovarian cancer cells through suppressing Wnt/β-catenin signaling. Our work highlights the therapeutic value of inhibiting Wnt/β-catenin in ovarian cancer. PMID:28090074

  16. miR-335 Targets SIAH2 and Confers Sensitivity to Anti-Cancer Drugs by Increasing the Expression of HDAC3

    PubMed Central

    Kim, Youngmi; Kim, Hyuna; Park, Deokbum; Jeoung, Dooil

    2015-01-01

    We previously reported the role of histone deacetylase 3 (HDAC3) in response to anti-cancer drugs. The decreased expression of HDAC3 in anti-cancer drug-resistant cancer cell line is responsible for the resistance to anti-cancer drugs. In this study, we investigated molecular mechanisms associated with regulation of HDAC3 expression. MG132, an inhibitor of proteasomal degradation, induced the expression of HDAC3 in various anti-cancer drug-resistant cancer cell lines. Ubiquitination of HDAC3 was observed in various anti-cancer drug-resistant cancer cell lines. HDAC3 showed an interaction with SIAH2, an ubiquitin E3 ligase, that has increased expression in various anti-cancer drug-resistant cancer cell lines. miRNA array analysis showed the decreased expression of miR-335 in these cells. Targetscan analysis predicted the binding of miR-335 to the 3′-UTR of SIAH2. miR-335-mediated increased sensitivity to anti-cancer drugs was associated with its effect on HDAC3 and SIAH2 expression. miR-335 exerted apoptotic effects and inhibited ubiquitination of HDAC3 in anti-cancer drug-resistant cancer cell lines. miR-335 negatively regulated the invasion, migration, and growth rate of cancer cells. The mouse xenograft model showed that miR-335 negatively regulated the tumorigenic potential of cancer cells. The down-regulation of SIAH2 conferred sensitivity to anti-cancer drugs. The results of the study indicated that the miR-335/SIAH2/HDAC3 axis regulates the response to anti-cancer drugs. PMID:25997740

  17. Model-based global sensitivity analysis as applied to identification of anti-cancer drug targets and biomarkers of drug resistance in the ErbB2/3 network

    PubMed Central

    Lebedeva, Galina; Sorokin, Anatoly; Faratian, Dana; Mullen, Peter; Goltsov, Alexey; Langdon, Simon P.; Harrison, David J.; Goryanin, Igor

    2012-01-01

    High levels of variability in cancer-related cellular signalling networks and a lack of parameter identifiability in large-scale network models hamper translation of the results of modelling studies into the process of anti-cancer drug development. Recently global sensitivity analysis (GSA) has been recognised as a useful technique, capable of addressing the uncertainty of the model parameters and generating valid predictions on parametric sensitivities. Here we propose a novel implementation of model-based GSA specially designed to explore how multi-parametric network perturbations affect signal propagation through cancer-related networks. We use area-under-the-curve for time course of changes in phosphorylation of proteins as a characteristic for sensitivity analysis and rank network parameters with regard to their impact on the level of key cancer-related outputs, separating strong inhibitory from stimulatory effects. This allows interpretation of the results in terms which can incorporate the effects of potential anti-cancer drugs on targets and the associated biological markers of cancer. To illustrate the method we applied it to an ErbB signalling network model and explored the sensitivity profile of its key model readout, phosphorylated Akt, in the absence and presence of the ErbB2 inhibitor pertuzumab. The method successfully identified the parameters associated with elevation or suppression of Akt phosphorylation in the ErbB2/3 network. From analysis and comparison of the sensitivity profiles of pAkt in the absence and presence of targeted drugs we derived predictions of drug targets, cancer-related biomarkers and generated hypotheses for combinatorial therapy. Several key predictions have been confirmed in experiments using human ovarian carcinoma cell lines. We also compared GSA-derived predictions with the results of local sensitivity analysis and discuss the applicability of both methods. We propose that the developed GSA procedure can serve as a

  18. Cell Line Derived 5-FU and Irinotecan Drug-Sensitivity Profiles Evaluated in Adjuvant Colon Cancer Trial Data

    PubMed Central

    Delorenzi, Mauro; Jensen, Thomas; Jensen, Peter Buhl; Bosman, Fred; Tejpar, Sabine; Roth, Arnaud; Brunner, Nils; Hansen, Anker; Knudsen, Steen

    2016-01-01

    Purpose This study evaluates whether gene signatures for chemosensitivity for irinotecan and 5-fluorouracil (5-FU) derived from in vitro grown cancer cell lines can predict clinical sensitivity to these drugs. Methods To test if an irinotecan signature and a SN-38 signature could identify patients who benefitted from the addition of irinotecan to 5-FU, we used gene expression profiles based on cell lines and clinical tumor material. These profiles were applied to expression data obtained from pretreatment formalin fixed paraffin embedded (FFPE) tumor tissue from 636 stage III colon cancer patients enrolled in the PETACC-3 prospective randomized clinical trial. A 5-FU profile developed similarly was assessed by comparing the PETACC-3 cohort with a cohort of 359 stage II colon cancer patients who underwent surgery but received no adjuvant therapy. Results There was no statistically significant association between the irinotecan or SN-38 profiles and benefit from irinotecan. The 5-FU sensitivity profile showed a statistically significant association with relapse free survival (RFS) (hazard ratio (HR) = 0.54 (0.41–0.71), p<1e-05) and overall survival (HR = 0.47 (0.34–0.63), p<1e-06) in the PETACC-3 subpopulation. The effect of the 5-FU profile remained significant in a multivariable Cox Proportional Hazards model, adjusting for several relevant clinicopathological parameters. No statistically significant effect of the 5-FU profile was observed in the untreated cohort of 359 patients (relapse free survival, p = 0.671). Conclusion The irinotecan predictor had no predictive value. The 5-FU predictor was prognostic in stage III patients in PETACC-3 but not in stage II patients with no adjuvant therapy. This suggests a potential predictive ability of the 5-FU sensitivity profile to identify colon cancer patients who may benefit from 5-FU, however, any biomarker predicting benefit for adjuvant 5-FU must be rigorously evaluated in independent cohorts. Given differences

  19. Determination of the primary target of a quinolone drug and the effect of quinolone resistance-conferring mutations by measuring quinolone sensitivity based on its mode of action.

    PubMed

    Pfeiffer, Emily S; Hiasa, Hiroshi

    2007-09-01

    We used an assay to measure quinolone sensitivity as a shift in the position of the cleavage-religation equilibrium. This assay was found to be useful in identifying the primary target of a quinolone drug and assessing the effect of quinolone resistance-conferring mutations.

  20. Confocal fluorescence microscopy: An ultra-sensitive tool used to evaluate intracellular antiretroviral nano-drug delivery in HeLa cells

    PubMed Central

    Mandal, Subhra; Zhou, You; Shibata, Annemarie; Destache, Christopher J.

    2015-01-01

    In the last decade, confocal fluorescence microscopy has emerged as an ultra-sensitive tool for real-time study of nanoparticles (NPs) fate at the cellular-level. According to WHO 2007 report, Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) is still one of the world’s major health threats by claiming approximately 7,000 new infections daily worldwide. Although combination antiretroviral drugs (cARV) therapy has improved the life-expectancy of HIV-infected patients, routine use of high doses of cARV has serious health consequences and requires complete adherence to the regimen for success. Thus, our research goal is to fabricate long-acting novel cARV loaded poly(lactide-co-glycolic acid) (PLGA) nanoparticles (cARV-NPs) as drug delivery system. However, important aspects of cARV-NPs that require special emphasis are their cellular-uptake, potency, and sustained drug release efficiency over-time. In this article, ultra-sensitive confocal microscopy is been used to evaluate the uptake and sustained drug release kinetics of cARV-NPs in HeLa cells. To evaluate with the above goal, instead of cARV-drug, Rhodamine6G dye (fluorescent dye) loaded NPs (Rho6G NPs) have been formulated. To correlate the Rhodamin6G release kinetics with the ARV release from NPs, a parallel HPLC study was also performed. The results obtained indicate that Rho6G NPs were efficiently taken up at low concentration (<500 ng/ml) and that release was sustained for a minimum of 4 days of treatment. Therefore, high drug assimilation and sustained release properties of PLGA-NPs make them an attractive vehicle for cARV nano-drug delivery with the potential to reduce drug dosage as well as the number of drug administrations per month. PMID:26221566

  1. Confocal fluorescence microscopy: An ultra-sensitive tool used to evaluate intracellular antiretroviral nano-drug delivery in HeLa cells

    NASA Astrophysics Data System (ADS)

    Mandal, Subhra; Zhou, You; Shibata, Annemarie; Destache, Christopher J.

    2015-08-01

    In the last decade, confocal fluorescence microscopy has emerged as an ultra-sensitive tool for real-time study of nanoparticles (NPs) fate at the cellular-level. According to WHO 2007 report, Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) is still one of the world's major health threats by claiming approximately 7,000 new infections daily worldwide. Although combination antiretroviral drugs (cARV) therapy has improved the life-expectancy of HIV-infected patients, routine use of high doses of cARV has serious health consequences and requires complete adherence to the regimen for success. Thus, our research goal is to fabricate long-acting novel cARV loaded poly(lactide-co-glycolic acid) (PLGA) nanoparticles (cARV-NPs) as drug delivery system. However, important aspects of cARV-NPs that require special emphasis are their cellular-uptake, potency, and sustained drug release efficiency over-time. In this article, ultra-sensitive confocal microscopy is been used to evaluate the uptake and sustained drug release kinetics of cARV-NPs in HeLa cells. To evaluate with the above goal, instead of cARV-drug, Rhodamine6G dye (fluorescent dye) loaded NPs (Rho6G NPs) have been formulated. To correlate the Rhodamin6G release kinetics with the ARV release from NPs, a parallel HPLC study was also performed. The results obtained indicate that Rho6G NPs were efficiently taken up at low concentration (<500 ng/ml) and that release was sustained for a minimum of 4 days of treatment. Therefore, high drug assimilation and sustained release properties of PLGA-NPs make them an attractive vehicle for cARV nano-drug delivery with the potential to reduce drug dosage as well as the number of drug administrations per month.

  2. Highly sensitive LC-MS/MS methods for urinary biological monitoring of occupational exposure to cyclophosphamide, ifosfamide, and methotrexate antineoplastic drugs and routine application.

    PubMed

    Canal-Raffin, Mireille; Khennoufa, Karim; Martinez, Béatrice; Goujon, Yves; Folch, Celia; Ducint, Dominique; Titier, Karine; Brochard, Patrick; Verdun-Esquer, Catherine; Molimard, Mathieu

    2016-10-21

    Highly sensitive ESI-LC-MS/MS methods were developed for urinary biological monitoring of occupational exposure to cyclophosphamide (CP), ifosfamide (IF), and methotrexate (MTX), which are hazardous antineoplastic drugs frequently handled by healthcare professionals. Extraction methods consisted of liquid/liquid extraction for simultaneous urinary CP and IF assays, and of solid phase extraction for the urinary MTX assay. A good linearity (r2>0.997), precision (CV<14.6%), and accuracy (bias<9.9%) were achieved for all compounds. The limit of detection (LOD) was 10pg/ml and the lower limit of quantification (LOQ) was 20pg/ml for all three drugs. Applying these methods in routine, more than 116 healthcare professionals occupationally exposed to antineoplastic drugs were monitored and 635 urines were analysed. Eleven healthcare professionals (9.5%) were found to be contaminated to at least one of the three antineoplastic drugs. Among analysed urines, 22 samples were found positives. The measured concentrations ranged from 20.1 to 1850pg/ml and, for six samples, concentrations were at CP trace level, between the LOD and LOQ values (10-20pg/ml). Such efficient analytical tools combining high specificity with high sensitivity are essential for reliable detection and routine biological monitoring of healthcare professionals occupationally exposed to these widely used antineoplastic drugs. These methods allow to monitor the healthcare professionals exposure to antineoplastic drugs in the aim to assess the effectiveness of collective and individual protective measures.

  3. Thermo-sensitive liposomes loaded with doxorubicin and lysine modified single-walled carbon nanotubes as tumor-targeting drug delivery system.

    PubMed

    Zhu, Xiali; Xie, Yingxia; Zhang, Yingjie; Huang, Heqing; Huang, Shengnan; Hou, Lin; Zhang, Huijuan; Li, Zhi; Shi, Jinjin; Zhang, Zhenzhong

    2014-11-01

    This report focuses on the thermo-sensitive liposomes loaded with doxorubicin and lysine-modified single-walled carbon nanotube drug delivery system, which was designed to enhance the anti-tumor effect and reduce the side effects of doxorubicin. Doxorubicin-lysine/single-walled carbon nanotube-thermo-sensitive liposomes was prepared by reverse-phase evaporation method, the mean particle size was 232.0 ± 5.6 nm, and drug entrapment efficiency was 86.5 ± 3.7%. The drug release test showed that doxorubicin released more quickly at 42℃ than at 37℃. Compared with free doxorubicin, doxorubicin-lysine/single-walled carbon nanotube-thermo-sensitive liposomes could efficiently cross the cell membranes and afford higher anti-tumor efficacy on the human hepatic carcinoma cell line (SMMC-7721) cells in vitro. For in vivo experiments, the relative tumor volumes of the sarcomaia 180-bearing mice in thermo-sensitive liposomes group and doxorubicin group were significantly smaller than those of N.S. group. Meanwhile, the combination of near-infrared laser irradiation at 808 nm significantly enhanced the tumor growth inhibition both on SMMC-7721 cells and the sarcomaia 180-bearing mice. The quality of life such as body weight, mental state, food and water intake of sarcomaia 180 tumor-bearing mice treated with doxorubicin-lysine/single-walled carbon nanotube-thermo-sensitive liposomes were much higher than those treated with doxorubicin. In conclusion, doxorubicin-lysine/single-walled carbon nanotube-thermo-sensitive liposomes combined with near-infrared laser irradiation at 808 nm may potentially provide viable clinical strategies for targeting delivery of anti-cancer drugs.

  4. Effect of anti-hyperlipidemia drugs on the alpha-tocopherol concentration and their potential for murine malaria infection.

    PubMed

    Kume, Aiko; Herbas, Maria Shirley; Shichiri, Mototada; Ishida, Noriko; Suzuki, Hiroshi

    2016-01-01

    The current preventions of malaria are protection against mosquito bites and taking chemoprophylactic anti-malarial drugs. However, drug therapies are usually associated with adverse events and emergency of drug-resistant malaria parasites. Previous study showed that host plasma alpha-tocopherol deficiency enhanced resistance against malaria infection in mice. Here, we report a new prevention strategy against malaria by using anti-hyperlipidemia drugs, ezetimibe, berberine, cholestyramine, and probucol to modify the host plasma alpha-tocopherol concentration. The drugs were mixed with diet and fed to C57BL/6J mice for 2 weeks. Although all drugs reduced plasma alpha-tocopherol concentration after 2 weeks of feeding, probucol-treated mice showed 90 % reduction and it was the lowest alpha-tocopherol concentration among the four drugs. Ezetimibe, berberine, and combination of ezetimibe and berberine pretreatment for 2 weeks were not effective against infection of Plasmodium yoelii XL17, a lethal strain, for survival and parasitemia in mice. Two-week pretreatment and 1-week treatment after infection of cholestyramine had also no effect on malaria infection. Survival rates of cholestyramine, ezetimibe, and/or berberine treated mice were 0-22 %. However, probucol caused significant decrease in parasitemia and increased in mice survival following 2-week pretreatment and 1-week treatment after infection. All control mice died while all probucol treated mice survived during the course of infection. Thus, probucol which reduced plasma alpha-tocopherol concentration was effective in enhancing the host to resist malaria infection in mice. Our finding indicates that plasma alpha-tocopherol reducing drugs like probucol might be a candidate for beneficial prevention strategy for travelers from malaria-free area.

  5. A better experimental method to detect the sensitivity of cancer cells to anticancer drugs after adenovirus-mediated introduction of two kinds of p53 in vivo.

    PubMed

    Wang, Hui; Li, WeiYing; Lai, BaiTang; Yang, XueHui; Zhang, ChunYan; Li, JinZhao; Zhu, YunZhong

    2015-09-01

    p53 plays an important role in drug responses by regulating cell cycle progression and inducing programmed cell death. The C-terminal of p53 self-regulates the protein negatively; however, whether it affects the sensitivity of cancer cells to anticancer drugs is unclear. In this study, two experimental methods were used to compare the sensitivity to anticancer drugs of human lung 801D cancer cells transfected with adenovirus bearing either full-length p53 or the deleted-C-terminal p53 in vivo. Adenovirus-mediated deliveries of full-length or deleted-C-terminal p53 were performed after development of tumors (the first method) or by infection into cells before xenotransplantation (the second method). The results showed that infection with the deleted-C-terminal p53 increased 801D cell sensitivity to anticancer drugs in the second, but not in the first method, as indicated by greater tumor-inhibition rates. In addition, compared with the first method, the second method resulted in viruses with more uniformly infected cells and the infection rates between groups were similar. This yielded smaller within-group variations and greater uniformity among transplanted tumors. The second method could circumvent the difficulties associated with intratumoral injection.

  6. Synthesis and Properties of pH-, Thermo-, and Salt-Sensitive Modified Poly(aspartic acid)/Poly(vinyl alcohol) IPN Hydrogel and Its Drug Controlled Release

    PubMed Central

    Lu, Jingqiong; Li, Yinhui; Hu, Deng; Chen, Xiaoling; Liu, Yongmei; Wang, Liping; Zhao, Yansheng

    2015-01-01

    Modified poly(aspartic acid)/poly(vinyl alcohol) interpenetrating polymer network (KPAsp/PVA IPN) hydrogel for drug controlled release was synthesized by a simple one-step method in aqueous system using poly(aspartic acid) grafting 3-aminopropyltriethoxysilane (KH-550) and poly(vinyl alcohol) (PVA) as materials. The hydrogel surface morphology and composition were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The thermal stability was analyzed by thermogravimetric analysis (TGA). The swelling properties and pH, temperature, and salt sensitivities of KPAsp, KPAsp/PVA semi-interpenetrating polymer network (semi-IPN), and KPAsp/PVA IPN hydrogels were also investigated. All of the three hydrogels showed ampholytic pH-responsive properties, and swelling behavior was also extremely sensitive to the temperature, ionic strength, and cationic species. Finally, the drug controlled release properties of the three hydrogels were evaluated and results indicated that three hydrogels could control drug release by external surroundings stimuli. The drug controlled release properties of KPAsp/PVA IPN hydrogel are the most outstanding, and the correlative measured release profiles of salicylic acid at 37°C were 32.6 wt% at pH = 1.2 (simulated gastric fluid) and 62.5 wt% at pH = 7.4 (simulated intestinal fluid), respectively. These results indicated that KPAsp/PVA IPN hydrogels are a promising carrier system for controlled drug delivery. PMID:26351630

  7. Development and Evaluation of Artesunate-Loaded Chitosan-Coated Lipid Nanocapsule as a Potential Drug Delivery System Against Breast Cancer.

    PubMed

    Tran, Tuan Hiep; Nguyen, Tuan Duc; Poudel, Bijay Kumar; Nguyen, Hanh Thuy; Kim, Jong Oh; Yong, Chul Soon; Nguyen, Chien Ngoc

    2015-12-01

    Artesunate (ART)--a well-known hydrophobic anti-malarial agent was incorporated in a polymer-lipid hybrid nanocolloidal system for anti-cancer therapeutic. The lipid negatively charged nanoemulsion was formulated by modified hot homogenization method then covered with positively charged chitosan via electrostatic interaction to obtain chitosan-coated lipid nanocapsule (ART-CLN). Physical properties of the system were characterized in terms of size, charge, morphology, drug loading capacity, and physical state. In addition, anti-cancer activities were confirmed by conducting MTT assay for ART and ART-CLN on different cancer cell lines. Obtained ART-CLN after coating chitosan revealed positive charge (13.2 ± 0.87 mV), small particle size (160.9 ± 3.5 nm), and spherical shape. High drug entrapment efficiency (95.49 ± 1.13%) and sustained release pattern were observed. Moreover, the good cellular uptake was recorded by flow cytometry as well as confocal image. Finally, ART-CLN exhibited stronger anti-cancer activity than free ART on breast cancer cell lines (MCF-7, MDA-MB-231). These results suggested that by loading ART into lipid core of polymer-lipid hybrid carrier, the activity and physical stability of ART can be significantly increased for cancer chemotherapy.

  8. Drug induced linear IgA disease with unusual features: Koebner phenomenon, local insulin sensitivity and annular blister of the nipples.

    PubMed

    Rashid Dar, Nasser; Raza, Naeem

    2008-01-01

    Linear IgA disease is an autoimmune subepidermal bullous disease in which linear IgA deposits are found at the basement membrane zone. It is classically idiopathic but may be drug induced. We report on a patient with drug induced linear IgA disease who exhibited certain unusual and interesting clinical features including isomorphic Koebner response, annular blister of the nipples and local insulin sensitivity. To the best of our knowledge, these clinical features have not yet been reported in linear IgA disease.

  9. Highly sensitive LC-MS/MS methods for the determination of seven human CYP450 activities using small oral doses of probe-drugs in human.

    PubMed

    Grangeon, Alexia; Gravel, Sophie; Gaudette, Fleur; Turgeon, Jacques; Michaud, Veronique

    2017-01-01

    Cocktails composed of several Cytochrome P450 (CYP450)-selective probe drugs have been shown of value to characterize in vivo drug-metabolism activities. Our objective was to develop and validate highly sensitive and selective LC-MS/MS assays allowing the determination of seven major human CYP450 isoenzyme activities following administration of low oral doses of a modified CYP450 probe-drug cocktail in patients. The seven-drug cocktail was composed of caffeine, bupropion, tolbutamide, omeprazole, dextromethorphan, midazolam (all administered concomitantly) and chlorzoxazone (administered separately) to phenotype for CYP1A2, 2B6, 2C9, 2C19, 2D6, 3A4/5 and 2E1, respectively. Serial plasma and urine samples were collected over an 8h period. The probe-drugs and their respective metabolites were measured in both human plasma and urine, except for omeprazole (plasma only) and chlorzoxazone (urine only). Samples were analyzed by high performance liquid chromatography with heated electrospray ionization tandem mass spectrometry (HPLC-HESI-MS/MS) using a Phenomenex Luna PFP (2) analytical column (3μm PFP(2) 150×3mm) for chromatographic separation. Optimal detection was achieved based on 3 different analytical methods; (1) isocratic elution with a mobile phase consisting of acetonitrile and water both fortified with 0.01% formic acid for the analysis of bupropion, tolbutamide, chlorzoxazone and their respective metabolites; (2) isocratic elution with a mobile phase composed of acetonitrile and ammonium formate (pH 3; 10mM) for omeprazole, dextromethorphan, midazolam and their metabolites; (3) for caffeine and paraxanthine, gradient elution using acetonitrile and 0.01% formic acid in water was used. All calibration functions were linear for all probe drugs and metabolites in both matrices over wide analytical ranges. The main advantages of our methods are the use of specific probe drugs available in most countries, the administration of small doses of probe drugs, small

  10. Antiplasmodial potential of medicinal plant extracts from Malaiyur and Javadhu hills of South India.

    PubMed

    Kamaraj, Chinnaperumal; Kaushik, Naveen Kumar; Mohanakrishnan, Dinesh; Elango, Gandhi; Bagavan, Asokan; Zahir, Abdul Abduz; Rahuman, Abdul Abdul; Sahal, Dinkar

    2012-08-01

    The emergence and spread of Plasmodium falciparum with resistance to chloroquine (CQ), the safest and cheapest anti-malarial drug, coupled with the increasing cost of alternative drugs especially in developing countries have necessitated the urgent need to tap the potential of plants for novel anti-malarials. The present study investigates the anti-malarial activity of the methanolic extracts of 13 medicinal plants from the Malaiyur and Javadhu hills of South India against blood stage CQ-sensitive (3D7) and CQ-resistant (INDO) strains of P. falciparum in culture using the fluorescence-based SYBR Green I assay. Sorbitol-synchronized parasites were incubated under normal culture conditions at 2% hematocrit and 1% parasitemia in the absence or presence of increasing concentrations of plant extracts. CQ and artemisinin were used as positive controls, while 0.4% DMSO was used as the negative control. The cytotoxic effects of extracts on host cells were assessed by functional assay using HeLa cells cultured in RPMI containing 10% fetal bovine serum, 0.21% sodium bicarbonate and 50 μg/mL gentamycin (complete medium). Plant extracts (bark methanol extracts of Annona squamosa (IC(50), 30 μg/mL), leaf extracts of Ocimum gratissimum (IC(50), 32 μg/mL), Ocimum tenuiflorum (IC(50), 31 μg/mL), Solanum torvum (IC(50), 31 μg/mL) and Justicia procumbens (IC(50), 63 μg/mL), showed moderate activity. The leaf extracts of Aristolochia indica (IC(50), 10 μg/mL), Cassia auriculata (IC(50), 14 μg/mL), Chrysanthemum indicum (IC(50), 20 μg/mL) and Dolichos biflorus (IC(50), 20 μg/mL) showed promising activity and low activity was observed in the flower methanol extracts of A. indica , leaf methanol extract of Catharanthus roseus, and Gymnema sylvestre (IC(50), >100 μg/mL). These four extracts exhibited promising IC(50) (μg/mL) of 17, 24, 19 and 24 respectively also against the CQ resistant INDO strain of P. falciparum. The high TC(50) in mammalian cell cytotoxicity assay and

  11. Clinical Features and Treatment Outcomes of Patients with Drug-Resistant and Drug-Sensitive Tuberculosis: A Historical Cohort Study in Porto Alegre, Brazil

    PubMed Central

    Micheletti, Vania Celina Dezoti; Kritski, Afrânio Lineu; Braga, José Ueleres

    2016-01-01

    Purpose To evaluate the clinical features and treatment outcomes of patients with pulmonary tuberculosis, stratified by level of drug resistance. Methods This was a historical cohort study based on data from the II National Anti-Tuberculosis Drug Resistance Survey (2006–2007) collected at eight participating health care facilities in Porto Alegre, southern Brazil. The cohort was followed for 3 years after the start of treatment. Results Of 299 cases of smear-positive pulmonary tuberculosis included in the study, 216 (72.2%) were diagnosed at five public primary health care units and 83 (27.8%) at three public hospitals. Among these cases, the prevalence of drug-resistant tuberculosis was 14.4%, and that of multidrug-resistant tuberculosis was 4.7%. Overall, 32.0% of drug-resistant and 2.0% of multidrug-resistant cases occurred in previously treated patients. The most common comorbidity in the sample was HIV infection (26.2%). There was no association between drug-resistant or multidrug-resistant tuberculosis and sociodemographic variables. Cure was achieved in 66.7% of patients, and the default rate was 21.2%. The 2-month sputum conversion rate was 34.2%, and the relapse rate was 16.9%. Patients with drug-resistant tuberculosis had lower rates of cure (45.2%) and 2-month sputum conversion (25%), as well as a higher relapse rate (30.7%). Conclusion These results highlight the urgent need for a more effective TB control program in this geographical setting, with a major emphasis on treatment of drug-resistant and multidrug-resistant tuberculosis. PMID:27505633

  12. Ex vivo cultures of glioblastoma in three-dimensional hydrogel maintain the original tumor growth behavior and are suitable for preclinical drug and radiation sensitivity screening

    SciTech Connect

    Jiguet Jiglaire, Carine; Baeza-Kallee, Nathalie; Denicolaï, Emilie; Barets, Doriane; Metellus, Philippe; and others

    2014-02-15

    Identification of new drugs and predicting drug response are major challenges in oncology, especially for brain tumors, because total surgical resection is difficult and radiation therapy or chemotherapy is often ineffective. With the aim of developing a culture system close to in vivo conditions for testing new drugs, we characterized an ex vivo three-dimensional culture system based on a hyaluronic acid-rich hydrogel and compared it with classical two-dimensional culture conditions. U87-MG glioblastoma cells and seven primary cell cultures of human glioblastomas were subjected to radiation therapy and chemotherapy drugs. It appears that 3D hydrogel preserves the original cancer growth behavior and enables assessment of the sensitivity of malignant gliomas to radiation and drugs with regard to inter-tumoral heterogeneity of therapeutic response. It could be used for preclinical assessment of new therapies. - Highlights: • We have compared primary glioblastoma cell culture in a 2D versus 3D-matrix system. • In 3D morphology, organization and markers better recapitulate the original tumor. • 3D-matrix culture might represent a relevant system for more accurate drug screening.

  13. Assessment of a five-layer laminate technique to measure the saturation solubility of drug in pressure-sensitive adhesive film.

    PubMed

    Reismann, Simone; Lee, Geoffrey

    2012-07-01

    A five-layer laminate technique is used to determine the saturation solubility of a drug in a thin polymer film, c(p)(s), of pressure-sensitive adhesive (PSA) used to prepare transdermal patches. A drug-loaded donor polymer film is attached via a separating membrane to an initially drug-free acceptor polymer film. Diffusion of drug occurs into the acceptor up to saturation solubility equilibrium. This systematic study of the technique using the drug tamsulosin and the PSA Duro Tak 87-4098 was a kinetic analysis of the diffusion process. It was found that the technique gives an equilibrium value for c(p)(s) in a PSA polymer film in the presence of crystalline phase of the drug in the donor. A highly permeable Perthese-separating membrane caused overshoot in the acceptor, most likely induced by initial supersaturation of the donor. Change to a less-permeable ethylene-vinyl-acetate-separating membrane avoided overshoot, but gave a prolonged time, >300 days, to equilibrium. Preloading the acceptor accelerated the equilibration process to approximately 50 days with the Perthese. Suitable experimental conditions are identified that, if performed correctly, allow the technique to give an equilibrium value for c(p)(s).

  14. Delayed photolysis of liposomes: a strategy for the precision timing of bolus drug release using ex-vivo photochemical sensitization

    NASA Astrophysics Data System (ADS)

    Kozikowski, Raymond T.; Sorg, Brian S.

    2012-03-01

    Chemotherapy is a standard treatment for metastatic cancer. However drug toxicity limits the dosage that can safely be used, thus reducing treatment efficacy. Drug carrier particles, like liposomes, can help reduce toxicity by shielding normal tissue from drug and selectively depositing drug in tumors. Over years of development, liposomes have been optimized to avoid uptake by the Reticuloendothelial System (RES) as well as effectively retain their drug content during circulation. As a result, liposomes release drug passively, by slow leakage, but this uncontrolled drug release can limit treatment efficacy as it can be difficult to achieve therapeutic concentrations of drug at tumor sites even with tumor-specific accumulation of the carriers. Lipid membranes can be photochemically lysed by both Type I (photosensitizer-substrate) and Type II (photosensitizer-oxygen) reactions. It has been demonstrated in red blood cells (RBCs) in vitro that these photolysis reactions can occur in two distinct steps: a light-initiated reaction followed by a thermally-initiated reaction. These separable activation steps allow for the delay of photohemolysis in a controlled manner using the irradiation energy, temperature and photosensitizer concentration. In this work we have translated this technique from RBCs to liposomal nanoparticles. To that end, we present in vitro data demonstrating this delayed bolus release from liposomes, as well as the ability to control the timing of this event. Further, we demonstrate for the first time the improved delivery of bioavailable cargo selectively to target sites in vivo.

  15. Balancing the stability and drug release of polymer micelles by the coordination of dual-sensitive cleavable bonds in cross-linked core.

    PubMed

    Deng, Hongzhang; Zhang, Yumin; Wang, Xue; Jianhuazhang; Cao, Yan; Liu, Jinjian; Liu, Jianfeng; Deng, Liandong; Dong, Anjie

    2015-01-01

    The optimal structure design of nanocarriers to inhibit premature release of anticancer drugs from nanocarriers during blood circulation and improve drug release inside tumor cells is still a significant issue for polymer micelles applied to antitumor drug delivery. Herein, in order to balance the contradiction between polymer micellar stability and drug release, dual-sensitive cleavable cross-linkages of benzoic imine conjugated disulfide bonds were introduced into the core of the amphiphilic copolymer micelles to form core-cross-linked micelles. First, biodegradable poly(ethylene glycol)-b-(polycaprolactone-g-poly(methacrylic acid-p-hydroxy benzaldehyde-cystamine)), i.e. mPEG-b-(PCL-g-P(MAA-Hy-Cys)) (PECMHC) copolymers were synthesized and assembled into PECMHC micelles (PECMHC Ms). Then, simply by introducing H2O2 to the PECMHC Ms dispersions to oxidate the thiol groups of cystamine moieties in the core, core-cross-linked PECMHC micelles (cc-PECMHC Ms) ∼100 nm in size were readily obtained in water. In vitro studies of doxorubicin (DOX)-loaded cc-PECMHC Ms show that the cross-linked core impeded the drug release in the physical conditions, owing to the high stability of the micelles against both extensive dilution and salt concentration, while it greatly accelerated DOX release in mildly acidic (pH ∼5.0-6.0) medium with glutathione, owing to the coordination of the pH-sensitive cleaving of benzoic imine bonds and the reduction-sensitive cleaving of disulfide bonds. The in vivo tissue distribution and tumor accumulation of the DOX-loaded cc-PECMHC Ms were monitored via fluorescence images of DOX. DOX-loaded cc-PECMHC Ms exhibited enhanced tumor accumulation because of their high stability in blood circulation and less DOX premature release. Therefore, the cc-PECMHC Ms with dual-sensitive cleavable bonds in the cross-linked core were of excellent biocompatibility, high extracellular stability and had intelligent intracellular drug release properties

  16. Malaria (For Parents)

    MedlinePlus

    ... it is passed from person to person (from mother to child in "congenital malaria," or through blood ... risk for malaria. Your doctor can give your family anti-malarial drugs to prevent the disease, which ...

  17. LIM-kinase 2, a regulator of actin dynamics, is involved in mitotic spindle integrity and sensitivity to microtubule-destabilizing drugs.

    PubMed

    Po'uha, S T; Shum, M S Y; Goebel, A; Bernard, O; Kavallaris, M

    2010-01-28

    LIM-kinase 2 (LIMK2) belongs to the LIMK family of proteins, which comprises LIMK1 and LIMK2. Both proteins regulate actin polymerization through phosphorylation and inactivation of the actin depolymerizing factor cofilin. In this study, we show that the level of LIMK2 protein is increased in neuroblastoma, BE(2)-C cells, selected for resistance to microtubule-destabilizing agents, vincristine and colchicine. However, the level of phosphorylated LIMK1 and LIMK2 was similar in the resistant and parental BE(2)-C cells. In contrast, the level of phospho-cofilin was greatly increased in the drug-resistant cells. Downregulation of LIMK2 expression increases sensitivity of neuroblastoma SH-EP cells to vincristine and vinblastine but not to microtubule-stabilizing agents, while it's overexpression increased its resistance to vincristine. Its vincristine-induced mitotic arrest was moderately inhibited in the LIMK2 knockdown cells, suggesting that the increased drug sensitivity is through an alternative mechanism other then mitotic arrest and apoptosis. Moreover, downregulation of LIMK2 expression induces formation of abnormal mitotic spindles, an effect enhanced in the presence of microtubule-destabilizing agents. LIMK2 is important for normal mitotic spindle formation and altered LIMK2 expression mediates sensitivity to microtubule destabilizing agents. These findings suggest that inhibition of LIMK2 activity may be used for the treatment of tumors resistant to microtubule-destabilizing drugs.

  18. Synthesis and application of the reduction-sensitive drug delivery system based on water-soluble ZnInAgS quantum dots

    NASA Astrophysics Data System (ADS)

    Deng, Dawei; Zhang, Rong; Qu, Lingzhi; Bao, Fangjian; Wang, Jie; Deng, Tao

    2016-10-01

    High-quality water-soluble quantum dots had been synthesized following the one-step method. Furtherly, the impact factors on the optical properties of quantum dots, which were the feed ratio of S/In and the reflux time, had been concerned emphatically. By changing the reaction parameters, we made the fluorescence emission of ZnInAgS quantum dot tunable from green to orange, and the maximum fluorescence quantum efficiency was up to 30%. Then we modified bovine serum albumin (BSA) on the surface of ZnInAgS quantum dot, which was conjugated with BSA-QDs through the linker of 3'3-dimercapto-diacetate DOX. Finally, the reduction-sensitive drug delivery system based on ZnInAgS quantum dots (QBSSD) was successfully constructed. The resultant QBSSD complex were observed to be significantly stable in aqueous solution. In addition, owing to their cellular reduction responsiveness at the cleavable disulfide linker, the QBSSD complex were able to release DOX rapidly. In vitro drug release and cell level release experiments proved that our QBSSD complexes could make a quick drug release in the environment with GSH. The efficacy experiments showed that our QBSSD complexes exhibited a strong killing effect to cancer cells, and low toxic to normal cells. All the results indicated that the reduction-sensitive drug delivery system was a promising model of administration.

  19. Decreased expression of nucleophosmin/B23 increases drug sensitivity of adriamycin-resistant Molt-4 leukemia cells through mdr-1 regulation and Akt/mTOR signaling.

    PubMed

    Wang, Lingyan; Chen, Buyuan; Lin, Minhui; Cao, Yanqin; Chen, Yingyu; Chen, Xinji; Liu, Tingbo; Hu, Jianda

    2015-03-01

    Nucleophosmin/B23 (NPM) is a nuclear protein with prosurvival and ribosomal RNA processing functions. However, the potential role of NPM involved in drug-resistance in leukemia has not been investigated clearly. In this study, we generated an adriamycin (ADM)-resistant lymphoblastic cell line Molt-4/ADR (MAR) by stepwise induction. Cell proliferation, sensitivity to chemotherapy agents and expressions of drug resistance related molecules were assessed. The IC50 of Molt-4 cells were 0.58±0.11μmol/L and MAR cells were 22.56±1.94μmol/L, meaning MAR cells were 38.63 fold resistant to Molt-4 cells. Furthermore, MAR cells gained an expression of mdr-1 (P-gp) and a higher expression of NPM compared to Molt-4 cells. Knockdown of NPM by RNA interference (RNAi) suppressed the viability of both Molt-4 and MAR cells. After NPM RNAi, the IC50 of MAR and Molt-4 cells were 3.83±0.38μmol/L and 0.19±0.02μmol/L respectively. Both of them revealed an increase of drug sensitivity with down-regulation of mdr-1 and Akt/mTOR signaling. Knockdown of mdr-1 could also reverse the drug resistance, with no change in NPM expression. It could be concluded that knockdown of NPM reversed the drug resistance by down-regulating P-gp and Akt/mTOR signal pathway, indicating that NPM may serve as a potential modulator in drug resistance.

  20. High sensitivity of an Ha-RAS transgenic model of superficial bladder cancer to metformin is associated with ~ 240-fold higher drug concentration in urine than serum

    PubMed Central

    Liu, Zhongbo; Yokoyama, Noriko N.; Blair, Chris A.; Li, Xuesen; Avizonis, Daina; Wu, Xue-Ru; Uchio, Edward; Youssef, Ramy; McClelland, Michael; Pollak, Michael; Zi, Xiaolin

    2016-01-01

    While pharmacoepidemiologic and laboratory studies have supported the hypothesis that the anti-diabetic drug metformin may be useful in treating or preventing cancer, there is limited evidence to suggest which specific cancer sites may be particularly sensitive. Sensitivity likely is determined both by features of tumor pathophysiology and by pharmacokinetic factors. We used UPII mutant Ha-ras transgenic mice that develop hyperplasia and low-grade, papillary urothelial cell carcinoma to determine if metformin has activity in a model of superficial bladder cancer. Metformin significantly improved survival, reduced urinary tract obstruction, reduced bladder weight (a surrogate for tumor volume) and led to clear activation of AMP α kinase and inhibition of mTOR signaling in neoplastic tissue. We investigated the basis of the unusual sensitivity of this model to metformin, and observed that following oral dosing, urothelium is exposed to drug concentrations via the urine that are ~ 240 fold higher than those in the circulation. In addition, we observed that bladder cancer cell lines (RT4, UMUC-3 and J82) with homozygous deletion of either TSC1 or PTEN are more sensitive to metformin than those (TEU2, TCCSUP and HT1376) with wild-type TSC1 and PTEN genes. Our findings provide a strong rationale for clinical trials of oral metformin in treatment of superficial bladder cancer. PMID:26921394

  1. Development and qualification of a high sensitivity, high throughput Q-PCR assay for quantitation of residual host cell DNA in purification process intermediate and drug substance samples.

    PubMed

    Zhang, Wei; Wu, Meng; Menesale, Emily; Lu, Tongjun; Magliola, Aeona; Bergelson, Svetlana

    2014-11-01

    Methods of high sensitivity, accuracy and throughput are needed for quantitation of low level residual host cell DNA in purification process intermediates and drug substances of therapeutic proteins. In this study, we designed primer/probe sets targeting repetitive Alu repeats or Alu-equivalent sequences in the human, Chinese hamster and murine genomes. When used in quantitative polymerase chain reactions (Q-PCRs), these primer/probe sets showed high species specificity and gave significantly higher sensitivity compared to those targeting the low copy number GAPDH gene. This allowed for detection of residual host cell DNA of much lower concentrations and, for some samples, eliminated the need for DNA extraction. By combining the high sensitivity Alu Q-PCR with high throughput automated DNA extraction using an automated MagMAX magnetic particle processor, we successfully developed and qualified a highly accurate, specific, sensitive and efficient method for the quantitation of residual host cell DNA in process intermediates and drug substances of multiple therapeutic proteins purified from cells of multiple species. Compared to the previous method using manual DNA extraction and primer/probe sets targeting the GAPDH gene, this new method increased our DNA extraction throughput by over sevenfold, and lowered the lower limit of quantitation by up to eightfold.

  2. Collagen gel droplet-embedded culture drug sensitivity testing in squamous cell carcinoma cell lines derived from human oral cancers: Optimal contact concentrations of cisplatin and fluorouracil

    PubMed Central

    Sakuma, Kaname; Tanaka, Akira; Mataga, Izumi

    2016-01-01

    The collagen gel droplet-embedded culture drug sensitivity test (CD-DST) is an anticancer drug sensitivity test that uses a method of three-dimensional culture of extremely small samples, and it is suited to primary cultures of human cancer cells. It is a useful method for oral squamous cell carcinoma (OSCC), in which the cancer tissues available for testing are limited. However, since the optimal contact concentrations of anticancer drugs have yet to be established in OSCC, CD-DST for detecting drug sensitivities of OSCC is currently performed by applying the optimal contact concentrations for stomach cancer. In the present study, squamous carcinoma cell lines from human oral cancer were used to investigate the optimal contact concentrations of cisplatin (CDDP) and fluorouracil (5-FU) during CD-DST for OSCC. CD-DST was performed in 7 squamous cell carcinoma cell lines derived from human oral cancers (Ca9-22, HSC-3, HSC-4, HO-1-N-1, KON, OSC-19 and SAS) using CDDP (0.15, 0.3, 1.25, 2.5, 5.0 and 10.0 µg/ml) and 5-FU (0.4, 0.9, 1.8, 3.8, 7.5, 15.0 and 30.0 µg/ml), and the optimal contact concentrations were calculated from the clinical response rate of OSCC to single-drug treatment and the in vitro efficacy rate curve. The optimal concentrations were 0.5 µg/ml for CDDP and 0.7 µg/ml for 5-FU. The antitumor efficacy of CDDP at this optimal contact concentration in CD-DST was compared to the antitumor efficacy in the nude mouse method. The T/C values, which were calculated as the ratio of the colony volume of the treatment group and the colony volume of the control group, at the optimal contact concentration of CDDP and of the nude mouse method were almost in agreement (P<0.05) and predicted clinical efficacy, indicating that the calculated optimal contact concentration is valid. Therefore, chemotherapy for OSCC based on anticancer drug sensitivity tests offers patients a greater freedom of choice and is likely to assume a greater importance in the selection of

  3. Neonatal sensitization to ethanol-induced breathing disruptions as a function of late prenatal exposure to the drug in the rat: modulatory effects of ethanol's chemosensory cues.

    PubMed

    Cullere, Marcela; Macchione, Ana Fabiola; Haymal, Beatriz; Paradelo, Martin; Langer, Marcos Daniel; Spear, Norman E; Molina, Juan Carlos

    2015-02-01

    Preclinical and clinical studies have systematically demonstrated abrupt changes in fetal respiratory patterns when the unborn organism is exposed to the effects of maternal ethanol intoxication. In subprimates, chronic exposure to this drug during gestation and infancy results in marked alterations of the plasticity of the respiratory network. These alterations are manifested in terms of an early incapability to overcome deleterious effects of hypoxic events as well as in terms of sensitization to ethanol's depressant effects upon breathing patterns. It has also been demonstrated that near term rat fetuses process ethanol's chemosensory cues when the drug contaminates the amniotic fluid and that associative learning processes occur due to the temporal contiguity existing between these cues and different ethanol-related physiological effects. In the present study during the course of late gestation (gestational days 17-20), pregnant rats were intragastrically administered with either 0.0 or 2.0 g/kg ethanol. Seven-day-old pups derived of these dams were evaluated in terms of respiration rates (breaths/min) and apneas when subjected to different experimental conditions. These conditions were defined by postnatal exposure to the drug (intragastric administrations of either 0.0, 0.5, 1.0 or 2.0 g/kg ethanol), postadministration time of evaluation (5-10 or 30-35 min) and olfactory context at test (no explicit ambient odor or ethanol ambient odor). The results, obtained via whole body plethysmography, indicated that brief prenatal experience with the drug sensitized the organisms to ethanol's depressant effects particularly when employing the higher ethanol doses. In turn, presence of ethanol odor at test potentiated the above mentioned respiratory alterations. Prenatal treatment with ethanol was not found to alter pharmacokinetic profiles resulting from postnatal exposure to the drug or to affect different morphometric parameters related with lung development. These

  4. A method for measurement of drug sensitivity of myeloma cells co-cultured with bone marrow stromal cells.

    PubMed

    Misund, Kristine; Baranowska, Katarzyna A; Holien, Toril; Rampa, Christoph; Klein, Dionne C G; Børset, Magne; Waage, Anders; Sundan, Anders

    2013-07-01

    The tumor microenvironment can profoundly affect tumor cell survival as well as alter antitumor drug activity. However, conventional anticancer drug screening typically is performed in the absence of stromal cells. Here, we analyzed survival of myeloma cells co-cultured with bone marrow stromal cells (BMSC) using an automated fluorescence microscope platform, ScanR. By staining the cell nuclei with DRAQ5, we could distinguish between BMSC and myeloma cells, based on their staining intensity and nuclear shape. Using the apoptotic marker YO-PRO-1, the effects of drug treatment on the viability of the myeloma cells in the presence of stromal cells could be measured. The method does not require cell staining before incubation with drugs, and less than 5000 cells are required per condition. The method can be used for large-scale screening of anticancer drugs on primary myeloma cells. This study shows the importance of stromal cell support for primary myeloma cell survival in vitro, as half of the cell samples had a marked increase in their viability when cultured in the presence of BMSC. Stromal cell-induced protection against common myeloma drugs is also observed with this method.

  5. Overexpression of microRNA-24 increases the sensitivity to paclitaxel in drug-resistant breast carcinoma cell lines via targeting ABCB9

    PubMed Central

    Gong, Jian-Ping; Yang, Liu; Tang, Jun-Wei; Sun, Peng; Hu, Qing; Qin, Jian-Wei; Xu, Xiao-Ming; Sun, Bei-Cheng; Tang, Jin-Hai

    2016-01-01

    Paclitaxel has been widely used in the treatment of breast cancer. However, the development of drug resistance often increases the failure of chemotherapy. Growing evidence has reported the significant role of microRNAs (miRs) in drug resistance. The present study identified that miR-24 was significantly downregulated in paclitaxel-resistant (PR) breast cancer patients and in MCF-7/PR human breast carcinoma cells, and that overexpression of miR-24 could increase the effect of paclitaxel on drug-resistant breast carcinoma cells. Furthermore, miR-24 could directly bind to the 3′-untranslated region of ATP binding cassette B9 to downregulate its expression, thereby reducing drug transportation and improving the anti-tumor effect of paclitaxel on breast cancer cells. In vivo experiments also demonstrated that overexpression of miR-24 could increase the sensitivity of drug-resistant MCF-7 cells to paclitaxel. In conclusion, the present results suggested a novel function for miR-24 in reducing paclitaxel resistance in breast cancer, which may be of important clinical significance. PMID:27895747

  6. Matrix Metalloproteinase 2-sensitive Multifunctional Polymeric Micelles for Tumor-specific Co-delivery of siRNA and Hydrophobic Drugs

    PubMed Central

    Zhu, Lin; Perche, Federico; Wang, Tao; Torchilin, Vladimir P

    2014-01-01

    Co-delivery of hydrophilic siRNA and hydrophobic drugs is one of the major challenges for nanomaterial-based medicine. Here, we present a simple but multifunctional micellar platform constructed by a matrix metalloproteinase 2 (MMP2)-sensitive copolymer (PEG-pp-PEI-PE) via self-assembly for tumor-targeted siRNA and drug co-delivery. The micellar nanocarrier possesses several key features for siRNA and drug delivery, including (i) excellent stability; (ii) efficient siRNA condensation by PEI; (iii) hydrophobic drug solubilization in the lipid “core”; (iv) passive tumor targeting via the enhanced permeability and retention (EPR) effect; (v) tumor targeting triggered by the up-regulated tumoral MMP2; and (vi) enhanced cell internalization after MMP2-activated exposure of the previously hidden PEI. These cooperative functions ensure the improved tumor targetability, enhanced tumor cell internalization, and synergistic antitumor activity of co-loaded siRNA and drug. PMID:24529391

  7. A comprehensive and sensitive method for hair analysis in drug-facilitated crimes and incorporation of zolazepam and tiletamine into hair after a single exposure.

    PubMed

    Kim, Jihyun; Yum, Hyesun; Jang, Moonhee; Shin, Ilchung; Yang, Wonkyung; Baeck, Seungkyung; Suh, Joon Hyuk; Lee, Sooyeun; Han, Sang Beom

    2016-01-01

    Hair is a highly relevant specimen that is used to verify drug exposure in victims of drug-facilitated crime (DFC) cases. In the present study, a new analytical method involving ultrahigh-performance liquid chromatography-tandem mass spectrometry was developed for determining the presence of model drugs, including zolazepam and tiletamine and their metabolites in hair specimens from DFCs. The incorporation of zolazepam and tiletamine into hair after a single exposure was investigated in Long-Evans rats with the ratio of the hair concentration to the area under the curve. For rapid and simple sample preparation, methanol extraction and protein precipitation were performed for hair and plasma, respectively. No interference was observed in drug-free hair or plasma, except for hair-derived diphenhydramine in blank hair. The coefficients of variance of the matrix effects were below 12%, and the recoveries of the analytes exceeded 70% in all of the matrices. The precision and accuracy results were satisfactory. The limits of quantification ranged from 20 to 50 pg in 10 mg of hair. The drug incorporation rates were 0.03 ± 0.01% for zolazepam and 2.09 ± 0.51% for tiletamine in pigmented hair. We applied the present method to real hair samples in order to determine the drug that was used in seven cases. These results suggest that this comprehensive and sensitive hair analysis method can successfully verify a drug after a single exposure in crimes and can be applied in forensic and clinical toxicology laboratories.

  8. Targeting Drug-Sensitive and -Resistant Strains of Mycobacterium tuberculosis by Inhibition of Src Family Kinases Lowers Disease Burden and Pathology.

    PubMed

    Chandra, Pallavi; Rajmani, R S; Verma, Garima; Bhavesh, Neel Sarovar; Kumar, Dhiraj

    2016-01-01

    In view of emerging drug resistance among bacterial pathogens, including Mycobacterium tuberculosis, the development of novel therapeutic strategies is increasingly being sought. A recent paradigm in antituberculosis (anti-TB) drug development is to target the host molecules that are crucial for intracellular survival of the pathogen. We previously showed the importance of Src tyrosine kinases in mycobacterial pathogenesis. Here, we report that inhibition of Src significantly reduced survival of H37Rv as well as multidrug-resistant (MDR) and extremely drug-resistant (XDR) strains of M. tuberculosis in THP-1 macrophages. Src inhibition was also effective in controlling M. tuberculosis infection in guinea pigs. In guinea pigs, reduced M. tuberculosis burden due to Src inhibition also led to a marked decline in the disease pathology. In agreement with the theoretical framework of host-directed approaches against the pathogen, Src inhibition was equally effective against an XDR strain in controlling infection in guinea pigs. We propose that Src inhibitors could be developed into effective host-directed anti-TB drugs, which could be indiscriminately used against both drug-sensitive and drug-resistant strains of M. tuberculosis. IMPORTANCE The existing treatment regimen for tuberculosis (TB) suffers from deficiencies like high doses of antibiotics, long treatment duration, and inability to kill persistent populations in an efficient manner. Together, these contribute to the emergence of drug-resistant tuberculosis. Recently, several host factors were identified which help intracellular survival of Mycobacterium tuberculosis within the macrophage. These factors serve as attractive targets for developing alternate therapeutic strategies against M. tuberculosis. This strategy promises to be effective against drug-resistant strains. The approach also has potential to considerably lower the risk of emergence of new drug-resistant strains. We explored tyrosine kinase Src as a

  9. Emodin enhances sensitivity of gallbladder cancer cells to platinum drugs via glutathion depletion and MRP1 downregulation.

    PubMed

    Wang, Wei; Sun, Yue-ping; Huang, Xin-zhi; He, Min; Chen, Yu-ying; Shi, Gui-ying; Li, Hui; Yi, Jing; Wang, Jian

    2010-04-15

    Glutathione conjugation and transportation of glutathione conjugates of anticancer drugs out of cells are important for detoxification of many anticancer drugs. Inhibition of this detoxification system has recently been proposed as a strategy to treat drug-resistant solid tumors. Gallbladder carcinoma is resistant to many anticancer drugs, therefore, it is needed to develop a novel strategy for cancer therapy. In the present study, we tested the effect of emodin (1,3,8-trihydroxy-6-methylanthraquinone), a reactive oxygen species (ROS) generator reported by our group previously, in combination with cisplatin (CDDP), carboplatin (CBP) or oxaliplatin in treating the gallbladder carcinoma cell line SGC996. Our results showed that co-treatment with emodin could remarkably enhance chemosensitivity of SGC996 cells in comparison with cisplatin, carboplatin or oxaliplatin treatment alone. We found that the mechanisms may be attributed to reduction of glutathione level, and downregulation of multidrug resistance-related protein 1 (MRP1) expression in SGC996 cells. The experiments on tumor-bearing mice showed that emodin/cisplatin co-treatment inhibited the tumor growth in vivo via increasing tumor cell apoptosis and downregulating MRP1 expression. In conclusion, emodin can work as an adjunct to enhance the anticancer effect of platinum drugs in gallbladder cancer cells via ROS-related mechanisms.

  10. Population structure and circulating genotypes of drug-sensitive and drug-resistant Mycobacterium tuberculosis clinical isolates in São Paulo state, Brazil

    PubMed Central

    Martins, Maria Conceição; Saraiva Giampaglia, Carmen M.; Oliveira, Rosângela S.; Simonsen, Vera; Latrilha, Fábio Oliveira; Moniz, Letícia Lisboa; Couvin, David; Rastogi, Nalin; Ferrazoli, Lucilaine

    2013-01-01

    São Paulo is the most populous Brazilian state and reports the largest number of tuberculosis cases in the country annually (over 18,500). This study included 193 isolates obtained during the 2nd Nationwide Survey on Mycobacterium tuberculosis Drug Resistance that was conducted in São Paulo state and 547 isolates from a laboratory based study of drug resistance that were analyzed by the Mycobacteria Reference Laboratory at the Institute Adolfo Lutz. Both studies were conducted from 2006 to 2008 and sought to determine the genetic diversity and pattern of drug resistance of M. tuberculosis isolates (MTC) circulating in São Paulo. The patterns obtained from the spoligotyping analysis demonstrated that 51/740 (6.9%) of the isolates corresponded to orphan patterns and that 689 (93.1%) of the isolates distributed into 144 shared types, including 119 that matched a preexisting shared type in the SITVIT2 database and 25 that were new isolates. A total of 77/144 patterns corresponded to unique isolates, while the remaining 67 corresponded to clustered patterns (n = 612 isolates clustered into groups of 2–84 isolates each). The evolutionarily ancient PGG1 lineages (Beijing, CAS1-DEL, EAI3-IND, and PINI2) were rarely detected in São Paulo and comprised only 13/740, or 1.76%, of the total isolates; all of the remaining 727/740, or 98.24%, of the MTC isolates from São Paulo state were from the recent PGG2/3 evolutionary isolates belonging to the LAM, T, S, X, and Haarlem lineages, i.e., the Euro-American group. This study provides the first overview of circulating genotypes of M. tuberculosis in São Paulo state and demonstrates that the clustered shared types containing seven or more M. tuberculosis isolates that are spread in São Paulo state included both resistant and susceptible isolates. PMID:23201043

  11. Population structure and circulating genotypes of drug-sensitive and drug-resistant Mycobacterium tuberculosis clinical isolates in São Paulo state, Brazil.

    PubMed

    Martins, Maria Conceição; Giampaglia, Carmen M Saraiva; Oliveira, Rosângela S; Simonsen, Vera; Latrilha, Fábio Oliveira; Moniz, Letícia Lisboa; Couvin, David; Rastogi, Nalin; Ferrazoli, Lucilaine

    2013-03-01

    São Paulo is the most populous Brazilian state and reports the largest number of tuberculosis cases in the country annually (over 18,500). This study included 193 isolates obtained during the 2nd Nationwide Survey on Mycobacterium tuberculosis Drug Resistance that was conducted in São Paulo state and 547 isolates from a laboratory based study of drug resistance that were analyzed by the Mycobacteria Reference Laboratory at the Institute Adolfo Lutz. Both studies were conducted from 2006 to 2008 and sought to determine the genetic diversity and pattern of drug resistance of M. tuberculosis isolates (MTC) circulating in São Paulo. The patterns obtained from the spoligotyping analysis demonstrated that 51/740 (6.9%) of the isolates corresponded to orphan patterns and that 689 (93.1%) of the isolates distributed into 144 shared types, including 119 that matched a preexisting shared type in the SITVIT2 database and 25 that were new isolates. A total of 77/144 patterns corresponded to unique isolates, while the remaining 67 corresponded to clustered patterns (n=612 isolates clustered into groups of 2-84 isolates each). The evolutionarily ancient PGG1 lineages (Beijing, CAS1-DEL, EAI3-IND, and PINI2) were rarely detected in São Paulo and comprised only 13/740, or 1.76%, of the total isolates; all of the remaining 727/740, or 98.24%, of the MTC isolates from São Paulo state were from the recent PGG2/3 evolutionary isolates belonging to the LAM, T, S, X, and Haarlem lineages, i.e., the Euro-American group. This study provides the first overview of circulating genotypes of M. tuberculosis in São Paulo state and demonstrates that the clustered shared types containing seven or more M. tuberculosis isolates that are spread in São Paulo state included both resistant and susceptible isolates.

  12. The Effectiveness and Safety of Fluoroquinolone-Containing Regimen as a First-Line Treatment for Drug-Sensitive Pulmonary Tuberculosis: A Systematic Review and Meta-Analysis

    PubMed Central

    Lee, Hyun Woo; Lee, Jung Kyu; Kim, Eunyoung; Yim, Jae-Joon; Lee, Chang-Hoon

    2016-01-01

    Background Fluoroquinolone is recommended as a pivotal antituberculous agent for treating multi-drug-resistant pulmonary tuberculosis. However, its effectiveness as first-line treatment remains controversial. The present study was conducted to validate the fluoroquinolone-containing regimen for drug-sensitive pulmonary tuberculosis. Methods We searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials until June 5, 2015. Randomized controlled trials (RCTs) that compared antituberculous regimens containing fluoroquinolone with the standard regimen were included. Results Eleven RCTs that included 6,334 patients were selected. Fluoroquinolone-containing regimens had a higher rate of sputum culture conversion at 2 months of treatment (M-H fixed odds ratio [OR], 1.36; 95% confidence interval [CI], 1.20–1.54). However, the outcomes were less favorable (M-H fixed OR, 0.69; 95% CI, 0.59–0.82) and the associated total adverse events were more frequent (M-H fixed OR, 1.84; 95% CI, 1.46–2.31) in the fluoroquinolone-containing regimen group, without a significant heterogeneity according to treatment duration. Treatment with the fluoroquinolone-containing regimen for 4 months showed a higher relapse rate. Conclusions Despite a higher culture conversion rate at 2 months of treatment, the fluoroquinolone-containing regimen had limitations, including less favorable outcomes and more adverse events, as the first-line therapy for drug-sensitive pulmonary tuberculosis. PMID:27455053

  13. Triplet-sensitized photodegradation of sulfa drugs containing six-membered heterocyclic groups: identification of an SO2 extrusion photoproduct.

    PubMed

    Boreen, Anne L; Arnold, William A; McNeill, Kristopher

    2005-05-15

    The aquatic photochemical behavior of a class of sulfa drugs containing six-membered heterocyclic substituents (sulfamethazine, sulfamerazine, sulfadiazine, sulfachloropyridazine, and sulfadimethoxine) was investigated. Photodegradation of the sulfa drugs in a natural water sample was significantly enhanced relative to the degradation in deionized water, with the exception of sulfadimethoxine. This indicated an indirect photochemical process that was identified through the use of quenchers to be attributable to interaction with triplet excited-state dissolved organic matter (3DOM). The direct photolysis rate constant and quantum yield for both the neutral and anionic species of each sulfa drug were calculated using matrix deconvolution methods. The quantum yield values range from 0.01 x 10(-3) for the neutral form of sulfadimethoxine to 5 x 10(-3) for the anionic form of sulfamethazine and are significantly lower than those observed in a previous study for sulfa drugs containing five-membered heterocyclic substituents, although the rate constants are of similar magnitude. The primary product formed in both direct and indirect photodegradation for all five compounds was identified as a sulfur dioxide extrusion product. The predicted environmental half-lives solely attributable to direct photolysis range from 8.6 h in midsummer at 30 degrees latitude in pH 7 surface water for sulfachloropyridazine to 420 h in midwinter at 45 degrees in pH 7 surface water for sulfadimethoxine. These half-lives, except for sulfadimethoxine, will be decreased by interaction with 3DOM.

  14. Rheological studies on pressure-sensitive silicone adhesives and drug-in-adhesive layers as a means to characterise adhesive performance.

    PubMed

    Ho, Kwong Yat; Dodou, Kalliopi

    2007-03-21

    Pressure-sensitive adhesives are viscoelastic polymers used in the formulation of transdermal patches that allow attachment of a patch onto the skin. Established criteria exist that correlate viscoelastic parameters with adhesive performance. In this study, fulfillment of the adhesive performance criteria was examined using two silicone adhesives with different tack properties. The viscoelastic parameters of high and low tack silicone adhesives (BIO-PSA High Tack 7-4302 and BIO-PSA Low Tack 7-4102) were determined and compared with the criteria described by Chu and Dahlquist. Drug-in-adhesive layers were prepared using the high tack adhesive combined with nortriptyline HCl or paracetamol. The effect of drug addition on the viscoelastic properties of the adhesive was examined. The high tack adhesive showed congruence with the established criteria although with a modified range of viscoelastic moduli to that described by Chu. Examination of the low tack adhesive showed that it did not possess the appropriate viscoelastic properties for bonding onto the skin. The addition of the drugs into the high tack adhesive caused a concentration-dependent increase in its cohesive strength. This effect was independent of the physicochemical properties of the drugs tested.

  15. A facile one-pot synthesis of starch functionalized graphene as nano-carrier for pH sensitive and starch-mediated drug delivery.

    PubMed

    Liu, Kunping; Wang, Yimin; Li, Huiming; Duan, Yixiang

    2015-04-01

    A fast, green and facile method was developed to prepare starch functionalized graphene nanosheets (starch-GNS) via the reduction of exfoliated graphene oxides by soluble starch, which acted both as a reductant and as a functionalization reagent for capping graphene nanosheets to prevent aggregation. The as-prepared starch-GNS exhibited good biocompatibility, which was deemed crucial for the biomedical application of graphene. Cellular toxicity tests suggested that the starch-GNS was nontoxic to SW-620 cells even at the relatively concentration of 200 μg mL(-1). After the loading of the commonly used anticancer drug hydroxycamptothecin (HCPT) via physisorption on starch-GNS, the HCPT@starch-GNS composite exhibited a high drug loading capacity and was therefore used for cellular imaging and drug delivery studies. Through the nonspecific endocytosis effect, the HCPT@starch-GNS composite was encapsulated into cytoplasm by SW-620 cancer cells. With the double action of an acid microenvironment and the diastase in SW-620 cells, the HCPT@starch-GNS composite showed high toxicity to the SW-620 cells and experienced a pH sensitive as well as a starch-mediated in vitro sustained release process, which had the potential advantage of improving therapeutic efficacy. Therefore, the starch-GNS composite could be used as an ideal nano-carrier for drug delivery and offered a new avenue for broadening the application of graphene in biomedicine.

  16. Determinants of Cation Permeation and Drug Sensitivity in Predicted Transmembrane Helix 9 and Adjoining Exofacial Re-entrant Loop 5 of Na+/H+ Exchanger NHE1.

    PubMed

    Jinadasa, Tushare; Josephson, Colin B; Boucher, Annie; Orlowski, John

    2015-07-17

    Mammalian Na(+)/H(+) exchangers (NHEs) regulate numerous physiological processes and are involved in the pathogenesis of several diseases, including tissue ischemia and reperfusion injuries, cardiac hypertrophy and failure, and cancer progression. Hence, NHEs are being targeted for pharmaceutical-based clinical therapies, but pertinent information regarding the structural elements involved in cation translocation and drug binding remains incomplete. Molecular manipulations of the prototypical NHE1 isoform have implicated several predicted membrane-spanning (M) helices, most notably M4, M9, and M11, as important determinants of cation permeation and drug sensitivity. Here, we have used substituted-cysteine accessibility mutagenesis and thiol-modifying methanethiosulfonate (MTS) reagents to further probe the involvement of evolutionarily conserved sites within M9 (residues 342-363) and the adjacent exofacial re-entrant loop 5 between M9 and M10 (EL5; residues 364-415) of a cysteine-less variant of rat NHE1 on its kinetic and pharmacological properties. MTS treatment significantly reduced the activity of mutants containing substitutions within M9 (H353C, S355C, and G356C) and EL5 (G403C and S405C). In the absence of MTS, mutants S355C, G403C, and S405C showed modest to significant decreases in their apparent affinities for Na(+) o and/or H(+) i. In addition, mutations Y370C and E395C within EL5, whereas failing to confer sensitivity to MTS, nevertheless, reduced the affinity for Na(+) o, but not for H(+) i. The Y370C mutant also exhibited higher affinity for ethylisopropylamiloride, a competitive antagonist of Na(+) o transport. Collectively, these results further implicate helix M9 and EL5 of NHE1 as important elements involved in cation transport and inhibitor sensitivity, which may inform rational drug design.

  17. Bcl-xL inhibition by molecular-targeting drugs sensitizes human pancreatic cancer cells to TRAIL.

    PubMed

    Hari, Yoko; Harashima, Nanae; Tajima, Yoshitsugu; Harada, Mamoru

    2015-12-08

    Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induces apoptosis in various types of cancer cells without damaging normal cells. However, in terms of pancreatic cancer, not all cancer cells are sensitive to TRAIL. In this study, we examined a panel of human pancreatic cancer cell lines for TRAIL sensitivity and investigated the effects of Bcl-2 family inhibitors on their response to TRAIL. Both ABT-263 and ABT-737 inhibited the function of Bcl-2, Bcl-xL, and Bcl-w. Of the nine pancreatic cancer cell lines tested, six showed no or low sensitivity to TRAIL, which correlated with protein expression of Bcl-xL. ABT-263 significantly sensitized four cell lines (AsPC-1, Panc-1, CFPAC-1, and Panc10.05) to TRAIL, with reduced cell viability and increased apoptosis. Knockdown of Bcl-xL, but not Bcl-2, by siRNA transfection increased the sensitivity of AsPC-1 and Panc-1 cells to TRAIL. ABT-263 treatment had no effect on protein expression of Bcl-2, Bcl-xL, or c-FLIPs. In Panc-1 cells, ABT-263 increased the surface expression of death receptor (DR) 5; the NF-κB pathway, but not endoplasmic reticulum stress, participated in the increase. In xenograft mouse models, the combination of TRAIL and ATB-737 suppressed the in vivo tumor growth of AsPC-1 and Panc-1 cells. These results indicate that Bcl-xL is responsible for TRAIL resistance in human pancreatic cancer cells, and that Bcl-2 family inhibitors could represent promising reagents to sensitize human pancreatic cancers in DR-targeting therapy.

  18. pH-sensitive micelles self-assembled from polymer brush (PAE-g-cholesterol)-b-PEG-b-(PAE-g-cholesterol) for anticancer drug delivery and controlled release

    PubMed Central

    Huang, Xiangxuan; Liao, Wenbo; Zhang, Gang; Kang, Shimin; Zhang, Can Yang

    2017-01-01

    A novel amphiphilic pH-sensitive triblock polymer brush (poly(β-amino esters)-g-cholesterol)-b-poly(ethylene glycol)-b-(poly(β-amino esters)-g-cholesterol) ((PAE-g-Chol)-b-PEG-b-(PAE-g-Chol)) was designed and synthesized successfully through a three-step reaction, and their self-assembled polymeric micelles were used as hydrophobic anticancer drug delivery carriers to realize effectively controlled release. The critical micelle concentrations were 6.8 μg/mL, 12.6 μg/mL, 17.4 μg/mL, and 26.6 μg/mL at pH values of 7.4, 6.5, 6.0, and 5.0, respectively. The trend of critical micelle concentrations indicated that the polymer had high stability that could prolong the circulation time in the body. The hydrodynamic diameter and zeta potential of the polymeric micelles were influenced significantly by the pH values. As pH decreased from 7.4 to 5.0, the particle size and zeta potential increased from 205.4 nm to 285.7 nm and from +12.7 mV to +47.0 mV, respectively. The pKb of the polymer was confirmed to be approximately 6.5 by the acid–base titration method. The results showed that the polymer had sharp pH-sensitivity because of the protonation of the amino groups, resulting in transformation of the PAE segment from hydrophobic to hydrophilic. Doxorubicin-loaded polymeric micelles were prepared with a high loading content (20%) and entrapment efficiency (60%) using the dialysis method. The in vitro results demonstrated that drug release rate and cumulative release were obviously dependent on pH values. Furthermore, the drug release mechanism was also controlled by the pH values. The polymer had barely any cytotoxicity, whereas the doxorubicin-loaded system showed high toxicity for HepG2 cells as free drugs. All the results proved that the pH-sensitive triblock polymer brush and its self-assembled micelle might be a potential delivery carrier for anticancer drugs with sustained release. PMID:28356738

  19. A sensitive enzyme-linked immunosorbent assay amplified by biotin-streptavidin system for detecting non-steroidal anti-inflammatory drug ketoprofen.

    PubMed

    Bu, Dan; Zhuang, Hui S; Yang, Guang X

    2014-01-01

    A sensitive biotin-streptavidin-amplified enzyme-linked immunosorbent assay (BA-ELISA) method was developed for detecting non-steroidal anti-inflammatory drug ketoprofen. Compared with traditional ELISA method, the sensitivity of proposed immunoassay was enhanced by the biotin-streptavidin system. Under the optimal condition, the median inhibitory concentration (IC50) was 0.25 ng mL(-1), with minor cross-reactivity to a number of structural analogs. This developed assay was successfully applied to detect the ketoprofen residues in different fish samples, and good recoveries (72.6-105.5%) were obtained. The results indicated that this immunoassay method could specifically detect trace ketoprofen residues and could be widely used for routine monitoring of food samples.

  20. Nanoscale Drug Delivery and Hyperthermia: The Materials Design and Preclinical and Clinical Testing of Low Temperature-Sensitive Liposomes Used in Combination with Mild Hyperthermia in the Treatment of Local Cancer

    PubMed Central

    Landon, Chelsea D.; Park, Ji-Young; Needham, David; Dewhirst, Mark W.

    2012-01-01

    The overall objective of liposomal drug delivery is to selectively target drug delivery to diseased tissue, while minimizing drug delivery to critical normal tissues. The purpose of this review is to provide an overview of temperature-sensitive liposomes in general and the Low Temperature-Sensitive Liposome (LTSL) in particular. We give a brief description of the material design of LTSL and highlight the likely mechanism behind temperature-triggered drug release. A complete review of the progress and results of the latest preclinical and clinical studies that demonstrate enhanced drug delivery with the combined treatment of hyperthermia and liposomes is provided as well as a clinical perspective on cancers that would benefit from hyperthermia as an adjuvant treatment for temperature-triggered chemotherapeutics. This review discusses the ideas, goals, and processes behind temperature-sensitive liposome development in the laboratory to the current use in preclinical and clinical settings. PMID:23807899

  1. Assessing spatiotemporal patterns of multidrug-resistant and drug-sensitive tuberculosis in a South American setting

    PubMed Central

    Lin, H.; Shin, S.; Blaya, J. A.; Zhang, Z.; Cegielski, P.; Contreras, C.; Asencios, L.; Bonilla, C.; Bayona, J.; Paciorek, C. J.; Cohen, T.

    2011-01-01

    Summary We examined the spatiotemporal distribution of laboratory-confirmed multidrug-resistant tuberculosis (MDR TB) cases and that of other TB cases in Lima, Peru with the aim of identifying mechanisms responsible for the rise of MDR TB in an urban setting. All incident cases of TB in two districts of Lima, Peru during 2005–2007 were included. The spatiotemporal distributions of MDR cases and other TB cases were compared with Ripley's K statistic. Of 11 711 notified cases, 1187 received drug susceptibility testing and 376 were found to be MDR. Spatial aggregation of patients with confirmed MDR disease appeared similar to that of other patients in 2005 and 2006; however, in 2007, cases with confirmed MDR disease were found to be more tightly grouped. Subgroup analysis suggests the appearance of resistance may be driven by increased transmission. Interventions should aim to reduce the infectious duration for those with drug-resistant disease and improve infection control. PMID:21205434

  2. NIR-Laser-Controlled Drug Release from DOX/IR-780-Loaded Temperature-Sensitive-Liposomes for Chemo-Photothermal Synergistic Tumor Therapy

    PubMed Central

    Yan, Fei; Duan, Wanlu; Li, Yekuo; Wu, Hao; Zhou, Yuli; Pan, Min; Liu, Hongmei; Liu, Xin; Zheng, Hairong

    2016-01-01

    NIR laser-induced photothermal therapy (PTT) through near-infrared agents has demonstrated the great potential in solid tumor ablation. However, the nonuniform heat distribution over tumors from PTT makes it insufficient to kill all tumor cells, resulting in tumor recurrence and inferior outcomes. To improve the tumor treatment efficacy, it is highly desirable to develop the combinational treatment of PTT with other modalities, especially with chemotherapeutic agents. Here we report a smart DOX/IR-780-loaded temperature-sensitive-liposome (DITSL) which can achieve NIR-laser-controlled drug release for chemo-photothermal synergistic tumor therapy. In this system, the liposoluble IR-780 was incorporated into the temperature-sensitive lipid bilayer and the soluble chemotherapeutic doxorubicin (DOX) was encapsulated in the hydrophilic core. The resulting DITSL is proved to be physiologically stable and can provide a fast and laser irradiation-controllable DOX release in the PBS and cellular conditions. We further employed this nanoparticle for tumor treatment, demonstrating significantly higher tumor inhibition efficacy than that of DOX-loaded temperature-sensitive-liposome (DTSL) or IR780-loaded temperature-sensitive-liposome (ITSL) in the in vitro cells and in vivo animals. Histological analysis further revealed much more apoptotic cells, confirming the advantageous anti-tumor effect of DITSL over DTSL or ITSL. Our study provides a promising strategy to realize chemo-photothermal synergistic combination therapy for breast tumors. PMID:27877239

  3. Prenatal Stress Alters Progestogens to Mediate Susceptibility to Sex-Typical, Stress-Sensitive Disorders, such as Drug Abuse: A Review.

    PubMed

    Frye, Cheryl A; Paris, Jason J; Osborne, Danielle M; Campbell, Joannalee C; Kippin, Tod E

    2011-01-01

    Maternal-offspring interactions begin prior to birth. Experiences of the mother during gestation play a powerful role in determining the developmental programming of the central nervous system. In particular, stress during gestation alters developmental programming of the offspring resulting in susceptibility to sex-typical and stress-sensitive neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. However, neither these effects, nor the underlying mechanisms, are well understood. Our hypothesis is that allopregnanolone, during gestation, plays a particularly vital role in mitigating effects of stress on the developing fetus and may mediate, in part, alterations apparent throughout the lifespan. Specifically, altered balance between glucocorticoids and progestogens during critical periods of development (stemming from psychological, immunological, and/or endocrinological stressors during gestation) may permanently influence behavior, brain morphology, and/or neuroendocrine-sensitive processes. 5α-reduced progestogens are integral in the developmental programming of sex-typical, stress-sensitive, and/or disorder-relevant phenotypes. Prenatal stress (PNS) may alter these responses and dysregulate allopregnanolone and its normative effects on stress axis function. As an example of a neurodevelopmental, neuropsychiatric, and/or neurodegenerative process, this review focuses on responsiveness to drugs of abuse, which is sensitive to PNS and progestogen milieu. This review explores the notion that allopregnanolone may effect, or be influenced by, PNS, with consequences for neurodevelopmental-, neuropsychiatric-, and/or neurodegenerative- relevant processes, such as addiction.

  4. Prenatal Stress Alters Progestogens to Mediate Susceptibility to Sex-Typical, Stress-Sensitive Disorders, such as Drug Abuse: A Review

    PubMed Central

    Frye, Cheryl A.; Paris, Jason J.; Osborne, Danielle M.; Campbell, Joannalee C.; Kippin, Tod E.

    2011-01-01

    Maternal–offspring interactions begin prior to birth. Experiences of the mother during gestation play a powerful role in determining the developmental programming of the central nervous system. In particular, stress during gestation alters developmental programming of the offspring resulting in susceptibility to sex-typical and stress-sensitive neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. However, neither these effects, nor the underlying mechanisms, are well understood. Our hypothesis is that allopregnanolone, during gestation, plays a particularly vital role in mitigating effects of stress on the developing fetus and may mediate, in part, alterations apparent throughout the lifespan. Specifically, altered balance between glucocorticoids and progestogens during critical periods of development (stemming from psychological, immunological, and/or endocrinological stressors during gestation) may permanently influence behavior, brain morphology, and/or neuroendocrine-sensitive processes. 5α-reduced progestogens are integral in the developmental programming of sex-typical, stress-sensitive, and/or disorder-relevant phenotypes. Prenatal stress (PNS) may alter these responses and dysregulate allopregnanolone and its normative effects on stress axis function. As an example of a neurodevelopmental, neuropsychiatric, and/or neurodegenerative process, this review focuses on responsiveness to drugs of abuse, which is sensitive to PNS and progestogen milieu. This review explores the notion that allopregnanolone may effect, or be influenced by, PNS, with consequences for neurodevelopmental-, neuropsychiatric-, and/or neurodegenerative- relevant processes, such as addiction. PMID:22022315

  5. Downregulation of caveolin-1 increases the sensitivity of drug-resistant colorectal cancer HCT116 cells to 5-fluorouracil

    PubMed Central

    Li, Zhaoyang; Wang, Ning; Huang, Changxin; Bao, Yanhong; Jiang, Yiqian; Zhu, Guiting

    2017-01-01

    Colorectal cancer is the third most common type of cancer in men and women. Chemotherapy is an important treatment strategy for patients with terminal stage cancer. However, the development of drug resistance hampers the effectiveness of chemotherapy. Therefore, an effective therapeutic approach to target chemoresistance-associated cellular molecules is required. In the present study, drug-resistant human colorectal cancer HCT116 cells were developed by treating HCT116 cells with increasing concentrations of 5-fluorouracil (5-FU). The present study indicated that the drug-resistance cells (DRC) were resistant to 5-FU compared with parental HCT116 cells by detecting cell survival using an MTT assay. Additionally, the expression of the chemoresistance-associated protein caveolin-1 (Cav-1) was assessed by reverse transcription-quantitative polymerase chain reaction and western blotting. The results revealed that the Cav-1 expression level was significantly higher in DRC compared with that in the parental HCT116 cells. Next, Cav-1 was silenced by small interfering RNA (siRNA) or was inhibited with its specific inhibitor methyl β-cyclodextrin (MCD). MTT assay demonstrated that Cav-1 siRNA and MCD resensitized DRC to 5-FU. These data reveal that Cav-1 was involved in the development of resistance, suggesting that Cav-1 is a potential target for the treatment of colorectal cancer chemoresistance. In addition, 5-FU combined with Cav-1 siRNA or its specific inhibitor may increase the effectiveness of the treatment strategy. PMID:28123586

  6. Nanoparticle Induced Cell Magneto-Rotation: Monitoring Morphology, Stress and Drug Sensitivity of a Suspended Single Cancer Cell

    PubMed Central

    Elbez, Remy; McNaughton, Brandon H.; Patel, Lalit; Pienta, Kenneth J.; Kopelman, Raoul

    2011-01-01

    Single cell analysis has allowed critical discoveries in drug testing, immunobiology and stem cell research. In addition, a change from two to three dimensional growth conditions radically affects cell behavior. This already resulted in new observations on gene expression and communication networks and in better predictions of cell responses to their environment. However, it is still difficult to study the size and shape of single cells that are freely suspended, where morphological changes are highly significant. Described here is a new method for quantitative real time monitoring of cell size and morphology, on single live suspended cancer cells, unconfined in three dimensions. The precision is comparable to that of the best optical microscopes, but, in contrast, there is no need for confining the cell to the imaging plane. The here first introduced cell magnetorotation (CM) method is made possible by nanoparticle induced cell magnetization. By using a rotating magnetic field, the magnetically labeled cell is actively rotated, and the rotational period is measured in real-time. A change in morphology induces a change in the rotational period of the suspended cell (e.g. when the cell gets bigger it rotates slower). The ability to monitor, in real time, cell swelling or death, at the single cell level, is demonstrated. This method could thus be used for multiplexed real time single cell morphology analysis, with implications for drug testing, drug discovery, genomics and three-dimensional culturing. PMID:22180784

  7. Transferrin receptor-targeted pH-sensitive micellar system for diminution of drug resistance and targetable delivery in multidrug-resistant breast cancer

    PubMed Central

    Gao, Wei; Ye, Guihua; Duan, Xiaochuan; Yang, Xiaoying; Yang, Victor C

    2017-01-01

    The emergence of drug resistance is partially associated with overproduction of transferrin receptor (TfR). To overcome multidrug resistance (MDR) and achieve tumor target delivery, we designed a novel biodegradable pH-sensitive micellar system modified with HAIYPRH, a TfR ligand (7pep). First, the polymers poly(l-histidine)-coupled polyethylene glycol-2000 (PHIS-PEG2000) and 7pep-modified 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol-2000 (7pep-DSPE-PEG2000) were synthesized, and the mixed micelles were prepared by blending of PHIS-PEG2000 and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol-2000 (DSPE-PEG2000) or 7pep-DSPE-PEG2000 (7-pep HD micelles). The micelles exhibited good size uniformity, high encapsulation efficiency, and a low critical micelle concentration. By changing the polymer ratio in the micellar formulation, the pH response range was specially tailored to pH ~6.0. When loaded with antitumor drug doxorubicin (DOX), the micelle showed an acid pH-triggering drug release profile. The cellular uptake and cytotoxicity study demonstrated that 7-pep HD micelles could significantly enhance the intracellular level and antitumor efficacy of DOX in multidrug-resistant cells (MCF-7/Adr), which attributed to the synergistic effect of poly(l-histidine)-triggered endolysosom escape and TfR-mediated endocytosis. Most importantly, the in vivo imaging study confirmed the target-ability of 7-pep HD micelles to MDR tumor. These findings indicated that 7-pep HD micelles would be a promising drug delivery system in the treatment of drug-resistant tumors. PMID:28223798

  8. pH-sensitive nanocarrier based on gold/silver core-shell nanoparticles decorated multi-walled carbon manotubes for tracing drug release in living cells.

    PubMed

    Chen, Peng; Wang, Zhuyuan; Zong, Shenfei; Zhu, Dan; Chen, Hui; Zhang, Yizhi; Wu, Lei; Cui, Yiping

    2016-01-15

    We fabricate a multifunctional nanocarrier based on multi-walled carbon nanotubes (MWCNTs) decorated with gold/silver core-shell nanoparticles (Au@Ag NPs) and fluorescein isothiocyanate (FITC) for tracking the intracellular drug release process. In the demonstrated nanocarrier, the Au@Ag NPs adsorbed on the surface of MWCNTs were labeled with the pH-dependent SERS reporter 4-Mercaptobenzoic acid (4MBA) for SERS based pH sensing. FITC was conjugated on MWCNTs to provide fluorescence signal for tracing the MWCNTs. Fluorescent doxorubicin (DOX) was used as the model drug which can be loaded onto MWCNTs via π-π stacking and released from the MWCNTs under acidic condition. By detecting the SERS spectrum of 4MBA, the pH value around the nanocarrier could be monitored. Besides, by tracing the fluorescence of FITC and DOX, we can also investigate the drug release process in cells. Experimental results show that the proposed nanocarrier retained a well pH-sensitive performance in living cells, and the DOX detached from MWCNTs inside the lysosomes and entered into the cytoplasm with the MWCNTs being left in lysosomes. To further investigate the drug release dynamics, 2-D color-gradient pH mapping were plotted, which were calculated from the SERS spectra of 4MBA. The detailed release process and carrier distribution have been recorded as environmental pH changes during cell endocytosis. Furthermore, we also confirmed that the proposed nanocarrier has a good biocompatibility. It indicates that the designed nanocarrier have a great potential in intraceable drug delivery, cancer cells imaging and pH monitoring.

  9. Nationwide survey of the development of drug resistance in the pediatric field in 2007 and 2010: drug sensitivity of Haemophilus influenzae in Japan (second report).

    PubMed

    Hoshino, Tadashi; Sato, Yoshitake; Toyonaga, Yoshikiyo; Hanaki, Hideaki; Sunakawa, Keisuke

    2013-06-01

    The Drug-Resistant Pathogen Surveillance Group in Pediatric Infectious Disease conducted national surveillance for Haemophilus influenzae in 2007 (phase 3) and 2010 (phase 4), following the previous surveillance conducted from 2000 to 2001 (phase 1) and in 2004 (phase 2). We examined the antimicrobial susceptibility for H. influenzae derived from clinical specimens of pediatric patients collected nationwide from 27 institutions during phases 3 (386 strains) and 4 (484 strains). The frequency of β-lactamase-nonproducing ampicillin (ABPC)-resistant (BLNAR) strains, which rapidly increased from 11.4 % in phase 1 to 43.4 % in phase 2, has gradually decreased from 38.3 % in phase 3 to 37.8 % in phase 4. In contrast, On the other hand, the frequency of β-lactamase-producing strains, which continuously decreased from 8.3 % in phase 1 to 4.4 % in phase 3, has increased to 8.7 % in phase 4. Prevalence of β-lactamase-producing clavulanic acid/amoxicillin-resistant (BLPACR) strains, especially, has increased from 1.6 % in phase 3 to 4.8 % in phase 4. The oral antimicrobial agents with the lowest MIC90 were levofloxacin in both phases, and tosufloxacin in phase 4 (≤0.063 μg/ml), whereas for intravenous use the corresponding agent was tazobactam/piperacillin in both phases (0.125 μg/ml). There was no increase in the MIC90 of most β-lactams between phase 3 and phase 4. In relationship to sex, age, presence of siblings, attendance at a daycare center, siblings' attendance at a daycare center, and prior administration of antimicrobial agents within 1 month, the frequency of β-lactamase-nonproducing ABPC-intermediately resistant (BLNAI) strains + BLNAR strains was high (P = 0.005) in cases with prior administration of antimicrobial agents in phase 3.

  10. Targeting the PI3K/AKT pathway via GLI1 inhibition enhanced the drug sensitivity of acute myeloid leukemia cells

    PubMed Central

    Liang, Hui; Zheng, Qi-Li; Fang, Peng; Zhang, Jian; Zhang, Tuo; Liu, Wei; Guo, Min; Robinson, Christopher L.; Chen, Shui-bing; Chen, Xiao-Ping; Chen, Fang-Ping; Zeng, Hui

    2017-01-01

    Combination targeted therapy is commonly used to treat acute myeloid leukemia (AML) patients, particularly in refractory/relapse (RR) population. However, concerns have been raised regarding the safety and patient tolerance of combination chemotherapy. It is critical to choose the appropriate treatment for precision therapy. We performed genome-wide RNA profiling using RNA-Seq to compare the RR group and the complete remission (CR) group (a total of 42 adult AML patients). The Hedgehog (Hh) and PI3K/AKT pathways were upregulated in the RR population, which was further confirmed by western blot and/or qPCR. Overexpression of GLI1 in AML cells led to increased AKT phosphorylation and decreased drug sensitivity, which was attenuated by GLI1 inhibition. By contrast, neither the expression of GLI1 nor apoptosis in response to Ara-C treatment of AML cells was significantly affected by PI3K inhibition. Furthermore, co-inhibition of GLI1 and PI3K induced apoptosis of hematopoietic stem/progenitor cells (HSPCs), which raised serious concerns about the side effects of this treatment. These results indicated that GLI1 inhibition alone, but not combined inhibition, is sufficient to enhance AML drug sensitivity, which provides a novel therapeutic strategy for AML treatment. PMID:28098170

  11. Omega-3 fatty acids, EPA and DHA induce apoptosis and enhance drug sensitivity in multiple myeloma cells but not in normal peripheral mononuclear cells.

    PubMed

    Abdi, J; Garssen, J; Faber, J; Redegeld, F A

    2014-12-01

    The n-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to enhance the effect of chemotherapeutic drugs in clinical studies in cancer patients and to induce apoptotic tumor cell death in vitro. Until now, EPA and DHA have never been investigated in multiple myeloma (MM). Human myeloma cells (L363, OPM-1, OPM-2 and U266) and normal peripheral blood mononuclear cells were exposed to EPA and DHA, and effects on mitochondrial function and apoptosis, caspase-3 activation, gene expression and drug toxicity were measured. Exposure to EPA and DHA induced apoptosis and increased sensitivity to bortezomib in MM cells. Importantly, they did not affect viability of normal human peripheral mononuclear cells. Messenger RNA expression arrays showed that EPA and DHA modulated genes involved in multiple signaling pathways including nuclear factor (NF) κB, Notch, Hedgehog, oxidative stress and Wnt. EPA and DHA inhibited NFκB activity and induced apoptosis through mitochondrial perturbation and caspase-3 activation. Our study suggests that EPA and DHA induce selective cytotoxic effects in MM and increase sensitivity to bortezomib and calls for further exploration into a potential application of these n-3 polyunsaturated fatty acids in the therapy of MM.

  12. New Antimalarial Hits from Dacryodes edulis (Burseraceae) - Part I: Isolation, In Vitro Activity, In Silico “drug-likeness” and Pharmacokinetic Profiles

    PubMed Central

    Zofou, Denis; Tematio, Esther Laure; Ntie-Kang, Fidele; Tene, Mathieu; Ngemenya, Moses N.; Tane, Pierre; Titanji, Vincent P. K.

    2013-01-01

    The aims of the present study were to identify the compounds responsible for the anti-malarial activity of Dacryoedes edulis (Burseraceae) and to investigate their suitability as leads for the treatment of drug resistant malaria. Five compounds were isolated from ethyl acetate and hexane extracts of D. edulis stem bark and tested against 3D7 (chloroquine-susceptible) and Dd2 (multidrug-resistant) strains of Plasmodium falciparum, using the parasite lactate dehydrogenase method. Cytotoxicity studies were carried out on LLC-MK2 monkey kidney epithelial cell-line. In silico analysis was conducted by calculating molecular descriptors using the MOE software running on a Linux workstation. The “drug-likeness” of the isolated compounds was assessed using Lipinski criteria, from computed molecular properties of the geometry optimized structures. Computed descriptors often used to predict absorption, distribution, metabolism, elimination and toxicity (ADMET) were used to assess the pharmacokinetic profiles of the isolated compounds. Antiplasmodial activity was demonstrated for the first time in five major natural products previously identified in D. edulis, but not tested against malaria parasites. The most active compound identified was termed DES4. It had IC50 values of 0.37 and 0.55 µg/mL, against 3D7 and Dd2 respectively. In addition, this compound was shown to act in synergy with quinine, satisfied all criteria of “Drug-likeness” and showed considerable probability of providing an antimalarial lead. The remaining four compounds also showed antiplasmodial activity, but were less effective than DES4. None of the tested compounds was cytotoxicity against LLC-MK2 cells, suggesting their selective activities on malaria parasites. Based on the high in vitro activity, low toxicity and predicted “Drug-likeness” DES4 merits further investigation as a possible drug lead for the treatment of malaria. PMID:24282507

  13. Influenza A virus infection in zebrafish recapitulates mammalian infection and sensitivity to anti-influenza drug treatment.

    PubMed

    Gabor, Kristin A; Goody, Michelle F; Mowel, Walter K; Breitbach, Meghan E; Gratacap, Remi L; Witten, P Eckhard; Kim, Carol H

    2014-11-01

    Seasonal influenza virus infections cause annual epidemics and sporadic pandemics. These present a global health concern, resulting in substantial morbidity, mortality and economic burdens. Prevention and treatment of influenza illness is difficult due to the high mutation rate of the virus, the emergence of new virus strains and increasing antiviral resistance. Animal models of influenza infection are crucial to our gaining a better understanding of the pathogenesis of and host response to influenza infection, and for screening antiviral compounds. However, the current animal models used for influenza research are not amenable to visualization of host-pathogen interactions or high-throughput drug screening. The zebrafish is widely recognized as a valuable model system for infectious disease research and therapeutic drug testing. Here, we describe a zebrafish model for human influenza A virus (IAV) infection and show that zebrafish embryos are susceptible to challenge with both influenza A strains APR8 and X-31 (Aichi). Influenza-infected zebrafish show an increase in viral burden and mortality over time. The expression of innate antiviral genes, the gross pathology and the histopathology in infected zebrafish recapitulate clinical symptoms of influenza infections in humans. This is the first time that zebrafish embryos have been infected with a fluorescent IAV in order to visualize infection in a live vertebrate host, revealing a pattern of vascular endothelial infection. Treatment of infected zebrafish with a known anti-influenza compound, Zanamivir, reduced mortality and the expression of a fluorescent viral gene product, demonstrating the validity of this model to screen for potential antiviral drugs. The zebrafish model system has provided invaluable insights into host-pathogen interactions for a range of infectious diseases. Here, we demonstrate a novel use of this species for IAV research. This model has great potential to advance our understanding of

  14. ZEB1 knockdown mediated using polypeptide cationic micelles inhibits metastasis and effects sensitization to a chemotherapeutic drug for cancer therapy

    NASA Astrophysics Data System (ADS)

    Fang, Shengtao; Wu, Lei; Li, Mingxing; Yi, Huqiang; Gao, Guanhui; Sheng, Zonghai; Gong, Ping; Ma, Yifan; Cai, Lintao

    2014-08-01

    Metastasis and drug resistance are the main causes for the failure in clinical cancer therapy. Emerging evidence suggests an intricate role of epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs) in metastasis and drug resistance. The EMT-activator ZEB1 is crucial in malignant tumor progression by linking EMT-activation and stemness-maintenance. Here, we used multifunctional polypeptide micelle nanoparticles (NP) as nanocarriers for the delivery of ZEB1 siRNA and doxorubicin (DOX). The nanocarriers could effectively deliver siRNA to the cytoplasm and knockdown the target gene in H460 cells and H460 xenograft tumors, leading to reduced EMT and repressed CSC properties in vitro and in vivo. The complex micelle nanoparticles with ZEB1 siRNA (siRNA-NP) significantly reduced metastasis in the lung. When DOX and siRNA were co-delivered by the nanocarriers (siRNA-DOX-NP), a synergistic therapeutic effect was observed, resulting in dramatic inhibition of tumor growth in a H460 xenograft model. These results demonstrated that the siRNA-NP or siRNA-DOX-NP complex targeting ZEB1 could be developed into a new therapeutic approach for non-small cell lung cancer (NSCLC) treatment.Metastasis and drug resistance are the main causes for the failure in clinical cancer therapy. Emerging evidence suggests an intricate role of epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs) in metastasis and drug resistance. The EMT-activator ZEB1 is crucial in malignant tumor progression by linking EMT-activation and stemness-maintenance. Here, we used multifunctional polypeptide micelle nanoparticles (NP) as nanocarriers for the delivery of ZEB1 siRNA and doxorubicin (DOX). The nanocarriers could effectively deliver siRNA to the cytoplasm and knockdown the target gene in H460 cells and H460 xenograft tumors, leading to reduced EMT and repressed CSC properties in vitro and in vivo. The complex micelle nanoparticles with ZEB1 siRNA (siRNA-NP) significantly reduced

  15. Sensitive screening of abused drugs in dried blood samples using ultra-high-performance liquid chromatography-ion booster-quadrupole time-of-flight mass spectrometry.

    PubMed

    Chepyala, Divyabharathi; Tsai, I-Lin; Liao, Hsiao-Wei; Chen, Guan-Yuan; Chao, Hsi-Chun; Kuo, Ching-Hua

    2017-03-31

    An increased rate of drug abuse is a major social problem worldwide. The dried blood spot (DBS) sampling technique offers many advantages over using urine or whole blood sampling techniques. This study developed a simple and efficient ultra-high-performance liquid chromatography-ion booster-quadrupole time-of-flight mass spectrometry (UHPLC-IB-QTOF-MS) method for the analysis of abused drugs and their metabolites using DBS. Fifty-seven compounds covering the most commonly abused drugs, including amphetamines, opioids, cocaine, benzodiazepines, barbiturates, and many other new and emerging abused drugs, were selected as the target analytes of this study. An 80% acetonitrile solvent with a 5-min extraction by Geno grinder was used for sample extraction. A Poroshell column was used to provide efficient separation, and under optimal conditions, the analytical times were 15 and 5min in positive and negative ionization modes, respectively. Ionization parameters of both electrospray ionization source and ion booster (IB) source containing an extra heated zone were optimized to achieve the best ionization efficiency of the investigated abused drugs. In spite of their structural diversity, most of the abused drugs showed an enhanced mass response with the high temperature ionization from an extra heated zone of IB source. Compared to electrospray ionization, the ion booster (IB) greatly improved the detection sensitivity for 86% of the analytes by 1.5-14-fold and allowed the developed method to detect trace amounts of compounds on the DBS cards. The validation results showed that the coefficients of variation of intra-day and inter-day precision in terms of the signal intensity were lower than 19.65%. The extraction recovery of all analytes was between 67.21 and 115.14%. The limits of detection of all analytes were between 0.2 and 35.7ngmL(-1). The stability study indicated that 7% of compounds showed poor stability (below 50%) on the DBS cards after 6 months of storage at

  16. Predicting drugs and proteins in parasite infections with topological indices of complex networks: theoretical backgrounds, applications, and legal issues.

    PubMed

    González-Díaz, Humberto; Romaris, Fernanda; Duardo-Sanchez, Aliuska; Pérez-Montoto, Lázaro G; Prado-Prado, Francisco; Patlewicz, Grace; Ubeira, Florencio M

    2010-01-01

    Quantitative Structure-Activity Relationship (QSAR) models have been used in Pharmaceutical design and Medicinal Chemistry for the discovery of anti-parasite drugs. QSAR models predict biological activity using as input different types of structural parameters of molecules. Topological Indices (TIs) are a very interesting class of these parameters. We can derive TIs from graph representations based on only nodes (atoms) and edges (chemical bonds). TIs are not time-consuming in terms of computational resources because they depend only on atom-atom connectivity information. This information expressed in the molecular graphs can be tabulated in the form of adjacency matrices easy to manipulate with computers. Consequently, TIs allow the rapid collection, annotation, retrieval, comparison and mining of molecular structures within large databases. The interest in TIs has exploded because we can use them to describe also macromolecular and macroscopic systems represented by complex networks of interactions (links) between the different parts of a system (nodes) such as: drug-target, protein-protein, metabolic, host-parasite, brain cortex, parasite disease spreading, Internet, or social networks. In this work, we review and comment on the following topics related to the use of TIs in anti-parasite drugs and target discovery. The first topic reviewed was: Topological Indices and QSAR for antiparasitic drugs. This topic included: Theoretical Background, QSAR for anti-malaria drugs, QSAR for anti-Toxoplasma drugs. The second topic was: TOMO-COMD approach to QSAR of antiparasitic drugs. We included in this topic: TOMO-COMD theoretical background and TOMO-COMD models for antihelmintic activity, Trichomonas, anti-malarials, anti-trypanosome compounds. The third section was inserted to discuss Topological Indices in the context of Complex Networks. The last section is devoted to the MARCH-INSIDE approach to QSAR of antiparasitic drugs and targets. This begins with a theoretical

  17. pH-sensitive drug loading/releasing in amphiphilic copolymer PAE-PEG: integrating molecular dynamics and dissipative particle dynamics simulations.

    PubMed

    Luo, Zhonglin; Jiang, Jianwen

    2012-08-20

    Molecular dynamics (MD) and dissipative particle dynamics (DPD) simulations are integrated to investigate the loading/releasing of anti-cancer drug camptothecin (CPT) in pH-sensitive amphiphilic copolymer, composed of hydrophobic poly(β-amino ester) (PAE) and hydrophilic methyl ether-capped poly(ethylene glycol) (PEG). MD simulation is used to estimate the Flory-Huggins interaction parameters and miscibility of binary components. On this basis, DPD simulation is applied to examine the micellization of PAE-PEG, CPT loading in PAE-PEG, and CPT releasing in PAEH-PEG. With increasing concentration, PAE-PEG forms spherical then disk-like micelles and finally vesicles, as a competitive counterbalance of free energies for the formation of shell, interface and core. CPT loading in PAE-PEG micelles/vesicles is governed by adsorption-growth-micellization mechanism, and CPT is loaded into both hydrophobic core and interface of hydrophobic core/hydrophilic shell. The predicted loading efficiency is close to experimental value. Similar to literature reports, the loading of high concentration of CPT is observed to cause morphology transition from micelles to vesicles. Upon protonation, CPT is released from micelles/vesicles by swelling-demicellization-releasing mechanism. This multi-scale simulation study provides microscopic insight into the mechanisms of drug loading and releasing, and might be useful for the design of new materials for high-efficacy drug delivery.

  18. A medusa-like β-cyclodextrin with 1-methyl-2-(2'-carboxyethyl) maleic anhydrides, a potential carrier for pH-sensitive drug delivery.

    PubMed

    Kang, Sunyoung; Park, Euddeum; Kim, Youngeun; Lee, Seonju; Kwon, Jiwoong; Cho, Hyungdo; Lee, Yan

    2014-08-01

    We developed a new pH-sensitive drug delivery carrier based on β-cyclodextrin (β-CD) and 1-methyl-2-(2'-carboxyethyl) maleic anhydrides (MCM). The primary hydroxyl groups of β-CD were successfully attached to MCM residues to produce a medusa-like β-CD-MCM. The MCM residue was conjugated with cephradine (CP) with high efficiency ( > 90%). More importantly, β-CD-MCM-CP responded to the small pH drop from 7.4 to 5.5 and released greater than 80% of the drugs within 0.5 h at pH 5.5. In addition, the inclusion complex between β-CD-MCM-CP and the adamantane derivative was formed by simple mixing to show the possibility of introducing multi-functionality. Based on these results, β-CD-MCM can target weakly acidic tissues or organelles, such as tumours, inflammatory tissues, abscesses or endosomes, and be easily modified with various functional moieties, such as ligands for cell binding or penetration, enabling more efficient and specific drug delivery.

  19. Computer simulations on the pH-sensitive tri-block copolymer containing zwitterionic sulfobetaine as a novel anti-cancer drug carrier.

    PubMed

    Min, Wenfeng; Zhao, Daohui; Quan, Xuebo; Sun, Delin; Li, Libo; Zhou, Jian

    2017-04-01

    In this work, dissipative particle dynamics (DPD) simulations were performed to study the self-assembled microstructures and doxorubicin (DOX) loading/release properties of pH-sensitive amphiphilic triblock copolymer: poly(ε-caprolactone)-b-poly(diethylaminoethyl methacrylate)-b-poly(sulfobetaine methacrylate) or poly (ethylene glycol methacrylate) (PCL-PDEA-PSBMA/PEGMA). Our results show that both copolymers can self-assemble into core-shell-corona micelles in aqueous environment. However, the corona structures are quite different for the two copolymer micelles. The shell layers formed by PEGMA have heterogeneous sizes while the shell layers in PCL-PDEA-PSBMA micelles are homogenous. This is mainly attributed to the stronger hydrophilicity of PSBMA than PEGMA. As the mole concentration of copolymer is increased from 10% to 50%, the microstructures formed by PCL-PDEA-PSBMA and DOX remains spherical micelles whereas PCL-PDEA-PEGMA undergoes structural transition from spherical to cylindrical and finally to lamellar micelles. Interestingly, the studied micelles have a pH-responsive drug release property, owing to the protonation of the PDEA block. The drug release process follows a "swelling-demicellization-release" mode. The multi-scale simulations demonstrate an avenue to the optimal design of nanomaterials for drug delivery with desired properties.

  20. Validated sensitive spectrofluorimetric method for determination of antihistaminic drug azelastine HCl in pure form and in pharmaceutical dosage forms: application to stability study.

    PubMed

    El-Masry, Amal A; Hammouda, Mohammed E A; El-Wasseef, Dalia R; El-Ashry, Saadia M

    2017-03-01

    A highly sensitive, simple and rapid spectrofluorimetric method was developed for the determination of azelastine HCl (AZL) in either its pure state or pharmaceutical dosage form. The proposed method was based on measuring the native fluorescence of the studied drug in 0.2 M H2 SO4 at λem  = 364 nm after excitation at λex  = 275 nm. Different experimental parameters were studied and optimized carefully to obtain the highest fluorescence intensity. The proposed method showed a linear dependence of the fluorescence intensity on drug concentration over a concentration range of 10-250 ng/mL, with a limit of detection of 1.52 ng/mL and limit of quantitation of 4.61 ng/mL. Moreover, the method was successfully applied to pharmaceutical preparations, with percent recovery values (± SD) of 99.96 (± 0.4) and 100.1 (± 0.52) for nasal spray and eye drops, respectively. The results were in good agreement with those obtained by the comparison method, as revealed by Student's t-test and the variance ratio F-test. The method was extended to study the stability of AZL under stress conditions, where the drug was exposed to neutral, acidic, alkaline, oxidative and photolytic degradation according to International Conference on Harmonization (ICH) guidelines. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Enhanced sensitivity of A549 cells to the cytotoxic action of anticancer drugs via suppression of Nrf2 by procyanidins from Cinnamomi Cortex extract

    SciTech Connect

    Ohnuma, Tomokazu; Matsumoto, Takashi; Itoi, Ayano; Kawana, Ayako; Nishiyama, Takahito; Ogura, Kenichiro; Hiratsuka, Akira

    2011-10-07

    Highlights: {yields} We found a novel inhibitor of Nrf2 known as a chemoresistance factor. {yields} Overexpressed Nrf2 in lung cancer cells was suppressed by Cinnamomi Cortex extract. {yields} Cytotoxic action of anticancer drugs in cells treated with the extract was enhanced. {yields} Procyanidin tetramers and pentamers were active components in suppressing Nrf2. -- Abstract: Nuclear factor-E2-related factor 2 (Nrf2) is an important cytoprotective transcription factor because Nrf2-regulated enzymes play a key role in antioxidant and detoxification processes. Recent studies have reported that lung cancer cells overexpressing Nrf2 exhibit increased resistance to chemotherapy. Suppression of overexpressed Nrf2 is needed for a new therapeutic approach against lung cancers. In the present study, we found that Cinnamomi Cortex extract (CCE) has an ability to suppress Nrf2-regulated enzyme activity and Nrf2 expression in human lung cancer A549 cells with high Nrf2 activity. Moreover, we demonstrated that CCE significantly enhances sensitivity of A549 cells to the cytotoxic action of doxorubicin and etoposide as well as increasing the intracellular accumulation of both drugs. These results suggest that CCE might be an effective concomitant agent to reduce anticancer drug resistance derived from Nrf2 overexpression. Bioactivity-guided fractionation revealed that procyanidin tetramers and pentamers contained in CCE were active components in suppressing Nrf2.

  2. Metabolic flux-driven sialylation alters internalization, recycling, and drug sensitivity of the epidermal growth factor receptor (EGFR) in SW1990 pancreatic cancer cells

    PubMed Central

    Mathew, Mohit P.; Tan, Elaine; Saeui, Christopher T.; Bovonratwet, Patawut; Sklar, Samuel; Bhattacharya, Rahul; Yarema, Kevin J.

    2016-01-01

    In prior work we reported that advanced stage, drug-resistant pancreatic cancer cells (the SW1990 line) can be sensitized to the EGFR-targeting tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib by treatment with 1,3,4-O-Bu3ManNAc (Bioorg. Med. Chem. Lett. (2015) 25(6):1223-7). Here we provide mechanistic insights into how this compound inhibits EGFR activity and provides synergy with TKI drugs. First, we showed that the sialylation of the EGFR receptor was at most only modestly enhanced (by ∼20 to 30%) compared to overall ∼2-fold increase in cell surface levels of this sugar. Second, flux-driven sialylation did not alter EGFR dimerization as has been reported for cancer cell lines that experience increased sialylation due to spontaneous mutations. Instead, we present evidence that 1,3,4-O-Bu3ManNAc treatment weakens the galectin lattice, increases the internalization of EGFR, and shifts endosomal trafficking towards non-clathrin mediated (NCM) endocytosis. Finally, by evaluating downstream targets of EGFR signaling, we linked synergy between 1,3,4-O-Bu3ManNAc and existing TKI drugs to a shift from clathrin-coated endocytosis (which allows EGFR signaling to continue after internalization) towards NCM endocytosis, which targets internalized moieties for degradation and thereby rapidly diminishes signaling. PMID:27613843

  3. Activation of the Nrf2 response by intrinsic hepatotoxic drugs correlates with suppression of NF-κB activation and sensitizes toward TNFα-induced cytotoxicity.

    PubMed

    Herpers, Bram; Wink, Steven; Fredriksson, Lisa; Di, Zi; Hendriks, Giel; Vrieling, Harry; de Bont, Hans; van de Water, Bob

    2016-05-01

    Drug-induced liver injury (DILI) is an important problem both in the clinic and in the development of new safer medicines. Two pivotal adaptation and survival responses to adverse drug reactions are oxidative stress and cytokine signaling based on the activation of the transcription factors Nrf2 and NF-κB, respectively. Here, we systematically investigated Nrf2 and NF-κB signaling upon DILI-related drug exposure. Transcriptomics analyses of 90 DILI compounds in primary human hepatocytes revealed that a strong Nrf2 activation is associated with a suppression of endogenous NF-κB activity. These responses were translated into quantitative high-content live-cell imaging of induction of a selective Nrf2 target, GFP-tagged Srxn1, and the altered nuclear translocation dynamics of a subunit of NF-κB, GFP-tagged p65, upon TNFR signaling induced by TNFα using HepG2 cells. Strong activation of GFP-Srxn1 expression by DILI compounds typically correlated with suppression of NF-κB nuclear translocation, yet reversely, activation of NF-κB by TNFα did not affect the Nrf2 response. DILI compounds that provided strong Nrf2 activation, including diclofenac, carbamazepine and ketoconazole, sensitized toward TNFα-mediated cytotoxicity. This was related to an adaptive primary protective response of Nrf2, since loss of Nrf2 enhanced this cytotoxic synergy with TNFα, while KEAP1 downregulation was cytoprotective. These data indicate that both Nrf2 and NF-κB signaling may be pivotal in the regulation of DILI. We propose that the NF-κB-inhibiting effects that coincide with a strong Nrf2 stress response likely sensitize liver cells to pro-apoptotic signaling cascades induced by intrinsic cytotoxic pro-inflammatory cytokines.

  4. The plant alkaloid and anti-leukemia drug homoharringtonine sensitizes resistant human colorectal carcinoma cells to TRAIL-induced apoptosis via multiple mechanisms.

    PubMed

    Beranova, Lenka; Pombinho, Antonio R; Spegarova, Jarmila; Koc, Michal; Klanova, Magdalena; Molinsky, Jan; Klener, Pavel; Bartunek, Petr; Andera, Ladislav

    2013-06-01

    TNF-related apoptosis-inducing ligand (TRAIL) is a pro-apoptotic ligand from the TNF-alpha family that is under consideration, along with agonistic anti-TRAIL receptor antibodies, as a potential anti-tumor agent. However, most primary human tumors are resistant to monotherapy with TRAIL apoptogens, and thus the potential applicability of TRAIL in anti-tumor therapy ultimately depends on its rational combination with drugs targeting these resistances. In our high-throughput screening for novel agents/drugs that could sensitize TRAIL-resistant colorectal cancer cells to TRAIL-induced apoptosis, we found homoharringtonine (HHT), a cephalotaxus alkaloid and tested anti-leukemia drug, to be a very effective, low nanomolar enhancer of TRAIL-mediated apoptosis/growth suppression of these resistant cells. Co-treatment of TRAIL-resistant RKO or HT-29 cells with HHT and TRAIL led to the effective induction of apoptosis and the complete elimination of the treated cells. HHT suppressed the expression of the anti-apoptotic proteins Mcl-1 and cFLIP and enhanced the TRAIL-triggered activation of JNK and p38 kinases. The shRNA-mediated down-regulation of cFLIP or Mcl-1 in HT-29 or RKO cells variably enhanced their TRAIL-induced apoptosis but it did not markedly sensitize them to TRAIL-mediated growth suppression. However, with the notable exception of RKO/sh cFLIP cells, the downregulation of cFLIP or Mcl-1 significantly lowered the effective concentration of HHT in HHT + TRAIL co-treatment. Combined HHT + TRAIL therapy also led to the strong suppression of HT-29 tumors implanted into immunodeficient mice. Thus, HHT represents a very efficient enhancer of TRAIL-induced apoptosis with potential application in TRAIL-based, anti-cancer combination therapy.

  5. An efficient PEGylated liposomal nanocarrier containing cell-penetrating peptide and pH-sensitive hydrazone bond for enhancing tumor-targeted drug delivery

    PubMed Central

    Ding, Yuan; Sun, Dan; Wang, Gui-Ling; Yang, Hong-Ge; Xu, Hai-Feng; Chen, Jian-Hua; Xie, Ying; Wang, Zhi-Qiang

    2015-01-01

    Cell-penetrating peptides (CPPs) as small molecular transporters with abilities of cell penetrating, internalization, and endosomal escape have potential prospect in drug delivery systems. However, a bottleneck hampering their application is the poor specificity for cells. By utilizing the function of hydration shell of polyethylene glycol (PEG) and acid sensitivity of hydrazone bond, we constructed a kind of CPP-modified pH-sensitive PEGylated liposomes (CPPL) to improve the selectivity of these peptides for tumor targeting. In CPPL, CPP was directly attached to liposome surfaces via coupling with stearate (STR) to avoid the hindrance of PEG as a linker on the penetrating efficiency of CPP. A PEG derivative by conjugating PEG with STR via acid-degradable hydrazone bond (PEG2000-Hz-STR, PHS) was synthesized. High-performance liquid chromatography and flow cytometry demonstrated that PHS was stable at normal neutral conditions and PEG could be completely cleaved from liposome surface to expose CPP under acidic environments in tumor. An optimal CPP density on liposomes was screened to guaranty a maximum targeting efficiency on tumor cells as well as not being captured by normal cells that consequently lead to a long circulation in blood. In vitro and in vivo studies indicated, in 4 mol% CPP of lipid modified system, that CPP exerted higher efficiency on internalizing the liposomes into targeted subcellular compartments while remaining inactive and free from opsonins at a maximum extent in systemic circulation. The 4% CPPL as a drug delivery system will have great potential in the clinical application of anticancer drugs in future. PMID:26491292

  6. In vitro culture and drug sensitivity assay of Plasmodium falciparum with nonserum substitute and acute-phase sera.

    PubMed

    Ringwald, P; Meche, F S; Bickii, J; Basco, L K

    1999-03-01

    The short-term in vitro growth of Plasmodium falciparum parasites in the asexual erythrocytic stage and the in vitro activities of eight standard antimalarial drugs were assessed and compared by using RPMI 1640 medium supplemented with 10% nonimmune human serum, 10% autologous or homologous acute-phase serum, or 0.5% Albumax I (lipid-enriched bovine serum albumin). In general, parasite growth was maximal with autologous (or homologous) serum, followed by Albumax I and nonimmune serum. The 50% inhibitory concentrations (IC50s) varied widely, depending on the serum or serum substitute. The comparison of IC50s between assays with autologous and nonimmune sera showed that monodesethylamodiaquine, halofantrine, pyrimethamine, and cycloguanil had similar IC50s. Although the IC50s of chloroquine, monodesethylamodiaquine, and dihydroartemisinin were similar with Albumax I and autologous sera, the IC50s of all test compounds obtained with Albumax I differed considerably from the corresponding values obtained with nonimmune serum. Our results suggest that Albumax I and autologous and homologous sera from symptomatic, malaria-infected patients may be useful alternative sources of serum for in vitro culture of P. falciparum isolates in the field. However, autologous sera and Albumax I do not seem to be suitable for the standardization of isotopic in vitro assays for all antimalarial drugs.

  7. Improved sensitivity by use of gas chromatography-positive chemical ionization triple quadrupole mass spectrometry for the analysis of drug related substances.

    PubMed

    Van Gansbeke, Wim; Polet, Michael; Hooghe, Fiona; Devos, Christophe; Van Eenoo, Peter

    2015-09-15

    In 2013, the World Anti-Doping Agency (WADA) drastically lowered the minimum required performance levels (MRPLs) of most doping substances, demanding a substantial increase in sensitivity of the existing methods. For a number of compounds, conventional electron impact ionization gas chromatography tandem mass spectrometry (GC-EI-MS/MS) is often no longer sufficient to reach these MRPLs and new strategies are required. In this study, the capabilities of positive ion chemical ionization (PICI) GC-MS/MS are investigated for a wide range of drug related compounds of various classes by injection of silylated reference standards. Ammonia as PICI reagent gas had superior characteristics for GC-MS/MS purposes than methane. Compared to GC-EI-MS/MS, PICI (with ammonia as reagent gas) provided more selective ion transitions and consequently, increased sensitivity by an average factor of 50. The maximum increase (by factor of 500-1000) was observed in the analysis of stimulants, namely chlorprenaline, furfenorex and phentermine. In total, improved sensitivity was obtained for 113 out of 120 compounds. A new GC-PICI-MS/MS method has been developed and evaluated for the detection of a wide variety of exogenous doping substances and the quantification of endogenous steroids in urine in compliance with the required MRPLs established by WADA in 2013. The method consists of a hydrolysis and extraction step, followed by derivatization and subsequent 1μL pulsed splitless injection on GC-PICI-MS/MS (16min run). The increased sensitivity allows the set up of a balanced screening method that meets the requirements for both quantitative and qualitative compounds: sufficient capacity and resolution in combination with high sensitivity and short analysis time. This resulted in calibration curves with a wide linear range (e.g., 48-9600ng/mL for androsterone and etiochanolone; all r(2)>0.99) without compromising the requirements for the qualitative compounds.

  8. Self-assembled micelles based on pH-sensitive PAE-g-MPEG-cholesterol block copolymer for anticancer drug delivery

    PubMed Central

    Zhang, Can Yang; Xiong, Di; Sun, Yao; Zhao, Bin; Lin, Wen Jing; Zhang, Li Juan

    2014-01-01

    A novel amphiphilic triblock pH-sensitive poly(β-amino ester)-g-poly(ethylene glycol) methyl ether-cholesterol (PAE-g-MPEG-Chol) was designed and synthesized via the Michael-type step polymerization and esterification condensation method. The synthesized copolymer was determined with proton nuclear magnetic resonance and gel permeation chromatography. The grafting percentages of MPEG and cholesterol were determined as 10.93% and 62.02%, calculated from the area of the characteristic peaks, respectively. The amphiphilic copolymer was confirmed to self-assemble into core/shell micelles in aqueous solution at low concentrations. The critical micelle concentrations were 6.92 and 15.14 mg/L at pH of 7.4 and 6.0, respectively, obviously influenced by the changes of pH values. The solubility of pH-responsive PAE segment could be transformed depending on the different values of pH because of protonation–deprotonation of the amino groups, resulting in pH sensitivity of the copolymer. The average particle size of micelles increased from 125 nm to 165 nm with the pH decreasing, and the zeta potential was also significantly changed. Doxorubicin (DOX) was entrapped into the polymeric micelles with a high drug loading level. The in vitro DOX release from the micelles was distinctly enhanced with the pH decreasing from 7.4 to 6.0. Toxicity testing proved that the DOX-loaded micelles exhibited high cytotoxicity in HepG2 cells, whereas the copolymer showed low toxicity. The results demonstrated how pH-sensitive PAE-g-MPEG-Chol micelles were proved to be a potential vector in hydrophobic drug delivery for tumor therapy. PMID:25364250

  9. Highly sensitive on-site detection of drugs adulterated in botanical dietary supplements using thin layer chromatography combined with dynamic surface enhanced Raman spectroscopy.

    PubMed

    Fang, Fang; Qi, Yunpeng; Lu, Feng; Yang, Liangbao

    2016-01-01

    The phenomenon of botanical dietary supplements (BDS) doped with illegal adulterants has become a serious problem all over the world, which could cause great threat to human's health. Therefore, it is of great value to identify BDS. Herein, we put forward a highly sensitive method for on-site detection of antitussive and antiasthmatic drugs adulterated in BDS using thin layer chromatography (TLC) combined with dynamic surface enhanced Raman spectroscopy (DSERS). Adulterants in BDS were separated on a TLC plate and located under UV illumination. Then DSERS detection was performed using a portable Raman spectrometer with 50% glycerol silver colloid serving as DSERS active substrate. Here, the effects of different solvents on detection efficacy were evaluated using phenformin hydrochloride (PHE) as a probe. It was shown that 50% glycerol resulted in higher SERS enhancement and relatively higher stability. Moreover, practical application of this novel TLC-DSERS method was demonstrated with rapid analysis of real BDS samples and one sample adulterated with benproperine phosphate (BEN) was found. Furthermore, the obtained result was verified by ultra performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QTOF/MS). The sensitivity of the TLC-DSERS technique is 1-2 orders of magnitude higher than that of TLC-SERS technique. The results turned out that this combined method would have good prospects for on-site and sensitive detection of adulterated BDS.