Potential New H1N1 Neuraminidase Inhibitors from Ferulic Acid and Vanillin: Molecular Modelling, Synthesis and in Vitro Assay

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Hariono, Maywan; Abdullah, Nurshariza; Damodaran, K. V.; Kamarulzaman, Ezatul E.; Mohamed, Nornisah; Hassan, Sharifah Syed; Shamsuddin, Shaharum; Wahab, Habibah A.

2016-12-01

We report the computational and experimental efforts in the design and synthesis of novel neuraminidase (NA) inhibitors from ferulic acid and vanillin. Two proposed ferulic acid analogues, MY7 and MY8 were predicted to inhibit H1N1 NA using molecular docking. From these two analogues, we designed, synthesised and evaluated the biological activities of a series of ferulic acid and vanillin derivatives. The enzymatic H1N1 NA inhibition assay showed MY21 (a vanillin derivative) has the lowest IC50 of 50 μM. In contrast, the virus inhibition assay showed MY15, a ferulic acid derivative has the best activity with the EC50 of ~0.95 μM. Modelling studies further suggest that these predicted activities might be due to the interactions with conserved and essential residues of NA with ΔGbind values comparable to those of oseltamivir and zanamivir, the two commercial NA inhibitors.

E119D Neuraminidase Mutation Conferring Pan-Resistance to Neuraminidase Inhibitors in an A(H1N1)pdm09 Isolate From a Stem-Cell Transplant Recipient.

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L'Huillier, Arnaud G; Abed, Yacine; Petty, Tom J; Cordey, Samuel; Thomas, Yves; Bouhy, Xavier; Schibler, Manuel; Simon, Audrey; Chalandon, Yves; van Delden, Christian; Zdobnov, Evgeny; Boquete-Suter, Patricia; Boivin, Guy; Kaiser, Laurent

2015-12-01

An influenza A(H1N1)pdm09 infection was diagnosed in a hematopoietic stem cell transplant recipient during conditioning regimen. He was treated with oral oseltamivir, later combined with intravenous zanamivir. The H275Y neuraminidase (NA) mutation was first detected, and an E119D NA mutation was identified during zanamivir therapy. Recombinant wild-type (WT) E119D and E119D/H275Y A(H1N1)pdm09 NA variants were generated by reverse genetics. Susceptibility to NA inhibitors (NAIs) was evaluated with a fluorometric assay using the 2'-(4-methylumbelliferyl)-α-D-N-acetylneuraminic acid (MUNANA) substrate. Susceptibility to favipiravir (T-705) was assessed using plaque reduction assays. The NA affinity and velocity values were determined with NA enzymatic studies. We identified an influenza A(H1N1)pdm09 E119D mutant that exhibited a marked increase in the 50% inhibitory concentrations against all tested NAIs (827-, 25-, 286-, and 702-fold for zanamivir, oseltamivir, peramivir, and laninamivir, respectively). The double E119D/H275Y mutation further increased oseltamivir and peramivir 50% inhibitory concentrations by 790- and >5000-fold, respectively, compared with the WT. The mutant viruses remained susceptible to favipiravir. The NA affinity and velocity values of the E119D variant decreased by 8.1-fold and 4.5-fold, respectively, compared with the WT. The actual emergence of a single NA mutation conferring pan-NAI resistance in the clinical setting reinforces the pressing need to develop new anti-influenza strategies. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Supply of neuraminidase inhibitors related to reduced influenza A (H1N1) mortality during the 2009-2010 H1N1 pandemic: an ecological study.

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Miller, Paula E; Rambachan, Aksharananda; Hubbard, Roderick J; Li, Jiabai; Meyer, Alison E; Stephens, Peter; Mounts, Anthony W; Rolfes, Melissa A; Penn, Charles R

2012-01-01

The influenza A (H1N1) pandemic swept across the globe from April 2009 to August 2010 affecting millions. Many WHO Member States relied on antiviral drugs, specifically neuraminidase inhibitors (NAIs) oseltamivir and zanamivir, to treat influenza patients in critical condition. Such drugs have been found to be effective in reducing severity and duration of influenza illness, and likely reduced morbidity during the pandemic. However, it is less clear whether NAIs used during the pandemic reduced H1N1 mortality. Country-level data on supply of oseltamivir and zanamivir were used to predict H1N1 mortality (per 100,000 people) from July 2009 to August 2010 in forty-two WHO Member States. Poisson regression was used to model the association between NAI supply and H1N1 mortality, with adjustment for economic, demographic, and health-related confounders. After adjustment for potential confounders, each 10% increase in kilograms of oseltamivir, per 100,000 people, was associated with a 1.6% reduction in H1N1 mortality over the pandemic period (relative rate (RR) = 0.84 per log increase in oseltamivir supply). While the supply of zanamivir was considerably less than that of oseltamivir in each Member State, each 10% increase in kilogram of active zanamivir, per 100,000, was associated with a 0.3% reduction in H1N1 mortality (RR = 0.97 per log increase). While there are limitations to the ecologic nature of these data, this analysis offers evidence of a protective relationship between antiviral drug supply and influenza mortality and supports a role for influenza antiviral use in future pandemics.

Influenza B viruses with mutation in the neuraminidase active site, North Carolina, USA, 2010-11.

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Sleeman, Katrina; Sheu, Tiffany G; Moore, Zack; Kilpatrick, Susan; Garg, Shikha; Fry, Alicia M; Gubareva, Larisa V

2011-11-01

Oseltamivir is 1 of 2 antiviral medications available for the treatment of influenza B virus infections. We describe and characterize a cluster of influenza B viruses circulating in North Carolina with a mutation in the neuraminidase active site that may reduce susceptibility to oseltamivir and the investigational drug peramivir but not to zanamivir.

Screening for Neuraminidase Inhibitor Resistance Markers among Avian Influenza Viruses of the N4, N5, N6, and N8 Neuraminidase Subtypes.

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Choi, Won-Suk; Jeong, Ju Hwan; Kwon, Jin Jung; Ahn, Su Jeong; Lloren, Khristine Kaith S; Kwon, Hyeok-Il; Chae, Hee Bok; Hwang, Jungwon; Kim, Myung Hee; Kim, Chul-Joong; Webby, Richard J; Govorkova, Elena A; Choi, Young Ki; Baek, Yun Hee; Song, Min-Suk

2018-01-01

Several subtypes of avian influenza viruses (AIVs) are emerging as novel human pathogens, and the frequency of related infections has increased in recent years. Although neuraminidase (NA) inhibitors (NAIs) are the only class of antiviral drugs available for therapeutic intervention for AIV-infected patients, studies on NAI resistance among AIVs have been limited, and markers of resistance are poorly understood. Previously, we identified unique NAI resistance substitutions in AIVs of the N3, N7, and N9 NA subtypes. Here, we report profiles of NA substitutions that confer NAI resistance in AIVs of the N4, N5, N6, and N8 NA subtypes using gene-fragmented random mutagenesis. We generated libraries of mutant influenza viruses using reverse genetics (RG) and selected resistant variants in the presence of the NAIs oseltamivir carboxylate and zanamivir in MDCK cells. In addition, two substitutions, H274Y and R292K (N2 numbering), were introduced into each NA gene for comparison. We identified 37 amino acid substitutions within the NA gene, 16 of which (4 in N4, 4 in N5, 4 in N6, and 4 in N8) conferred resistance to NAIs (oseltamivir carboxylate, zanamivir, or peramivir) as determined using a fluorescence-based NA inhibition assay. Substitutions conferring NAI resistance were mainly categorized as either novel NA subtype specific (G/N147V/I, A246V, and I427L) or previously reported in other subtypes (E119A/D/V, Q136K, E276D, R292K, and R371K). Our results demonstrate that each NA subtype possesses unique NAI resistance markers, and knowledge of these substitutions in AIVs is important in facilitating antiviral susceptibility monitoring of NAI resistance in AIVs. IMPORTANCE The frequency of human infections with avian influenza viruses (AIVs) has increased in recent years. Despite the availability of vaccines, neuraminidase inhibitors (NAIs), as the only available class of drugs for AIVs in humans, have been constantly used for treatment, leading to the inevitable emergence

Different neuraminidase inhibitor susceptibilities of human H1N1, H1N2, and H3N2 influenza A viruses isolated in Germany from 2001 to 2005/2006.

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Bauer, Katja; Richter, Martina; Wutzler, Peter; Schmidtke, Michaela

2009-04-01

In the flu season 2005/2006 amantadine-resistant human influenza A viruses (FLUAV) of subtype H3N2 circulated in Germany. This raises questions on the neuraminidase inhibitor (NAI) susceptibility of FLUAV. To get an answer, chemiluminescence-based neuraminidase inhibition assays were performed with 51 H1N1, H1N2, and H3N2 FLUAV isolated in Germany from 2001 to 2005/2006. According to the mean IC(50) values (0.38-0.91 nM for oseltamivir and 0.76-1.13 nM for zanamivir) most H1N1 and H3N2 FLUAV were NAI-susceptible. But, about four times higher zanamivir concentrations were necessary to inhibit neuraminidase activity of H1N2 viruses. Two H1N1 isolates were less susceptible to both drugs in NA inhibition as well as virus yield reduction assays. Results from sequence analysis of viral hemagglutinin and neuraminidase genes and evolutionary analysis of N2 gene revealed (i) different subclades for N2 in H1N2 and H3N2 FLUAV that could explain the differences in zanamivir susceptibility among these viruses and (ii) specific amino acid substitutions in the neuraminidase segment of the two less NAI-susceptible H1N1 isolates. One H3N2 was isolate proved to be a mixture of a NA deletion mutant and full-length NA viruses.

Oseltamivir Prophylaxis Reduces Inflammation and Facilitates Establishment of Cross-Strain Protective T Cell Memory to Influenza Viruses.

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Nicola L Bird

Full Text Available CD8(+ T cells directed against conserved viral regions elicit broad immunity against distinct influenza viruses, promote rapid virus elimination and enhanced host recovery. The influenza neuraminidase inhibitor, oseltamivir, is prescribed for therapy and prophylaxis, although it remains unclear how the drug impacts disease severity and establishment of effector and memory CD8(+ T cell immunity. We dissected the effects of oseltamivir on viral replication, inflammation, acute CD8(+ T cell responses and the establishment of immunological CD8(+ T cell memory. In mice, ferrets and humans, the effect of osteltamivir on viral titre was relatively modest. However, prophylactic oseltamivir treatment in mice markedly reduced morbidity, innate responses, inflammation and, ultimately, the magnitude of effector CD8(+ T cell responses. Importantly, functional memory CD8(+ T cells established during the drug-reduced effector phase were capable of mounting robust recall responses. Moreover, influenza-specific memory CD4(+ T cells could be also recalled after the secondary challenge, while the antibody levels were unaffected. This provides evidence that long-term memory T cells can be generated during an oseltamivir-interrupted infection. The anti-inflammatory effect of oseltamivir was verified in H1N1-infected patients. Thus, in the case of an unpredicted influenza pandemic, while prophylactic oseltamivir treatment can reduce disease severity, the capacity to generate memory CD8(+ T cells specific for the newly emerged virus is uncompromised. This could prove especially important for any new influenza pandemic which often occurs in separate waves.

Inhibition of neuraminidase by Ganoderma triterpenoids and implications for neuraminidase inhibitor design

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Zhu, Qinchang; Bang, Tran Hai; Ohnuki, Koichiro; Sawai, Takashi; Sawai, Ken; Shimizu, Kuniyoshi

2015-01-01

Neuraminidase (NA) inhibitors are the dominant antiviral drugs for treating influenza in the clinic. Increasing prevalence of drug resistance makes the discovery of new NA inhibitors a high priority. Thirty-one triterpenoids from the medicinal mushroom Ganoderma lingzhi were analyzed in an in vitro NA inhibition assay, leading to the discovery of ganoderic acid T-Q and TR as two inhibitors of H5N1 and H1N1 NAs. Structure-activity relationship studies revealed that the corresponding triterpenoid structure is a potential scaffold for the design of NA inhibitors. Using these triterpenoids as probes we found, through further in silico docking and interaction analysis, that interactions with the amino-acid residues Arg292 and/or Glu119 of NA are critical for the inhibition of H5N1 and H1N1. These findings should prove valuable for the design and development of NA inhibitors. PMID:26307417

Coadministration of Hedera helix L. Extract Enabled Mice to Overcome Insufficient Protection against Influenza A/PR/8 Virus Infection under Suboptimal Treatment with Oseltamivir.

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Hong, Eun-Hye; Song, Jae-Hyoung; Shim, Aeri; Lee, Bo-Ra; Kwon, Bo-Eun; Song, Hyuk-Hwan; Kim, Yeon-Jeong; Chang, Sun-Young; Jeong, Hyeon Gun; Kim, Jong Geal; Seo, Sang-Uk; Kim, HyunPyo; Kwon, YongSoo; Ko, Hyun-Jeong

2015-01-01

Several anti-influenza drugs that reduce disease manifestation exist, and although these drugs provide clinical benefits in infected patients, their efficacy is limited by the emergence of drug-resistant influenza viruses. In the current study, we assessed the therapeutic strategy of enhancing the antiviral efficacy of an existing neuraminidase inhibitor, oseltamivir, by coadministering with the leaf extract from Hedera helix L, commonly known as ivy. Ivy extract has anti-inflammatory, antibacterial, antifungal, and antihelminthic properties. In the present study, we investigated its potential antiviral properties against influenza A/PR/8 (PR8) virus in a mouse model with suboptimal oseltamivir that mimics a poor clinical response to antiviral drug treatment. Suboptimal oseltamivir resulted in insufficient protection against PR8 infection. Oral administration of ivy extract with suboptimal oseltamivir increased the antiviral activity of oseltamivir. Ivy extract and its compounds, particularly hedrasaponin F, significantly reduced the cytopathic effect in PR8-infected A549 cells in the presence of oseltamivir. Compared with oseltamivir treatment alone, coadministration of the fraction of ivy extract that contained the highest proportion of hedrasaponin F with oseltamivir decreased pulmonary inflammation in PR8-infected mice. Inflammatory cytokines and chemokines, including tumor necrosis factor-alpha and chemokine (C-C motif) ligand 2, were reduced by treatment with oseltamivir and the fraction of ivy extract. Analysis of inflammatory cell infiltration in the bronchial alveolar of PR8-infected mice revealed that CD11b+Ly6G+ and CD11b+Ly6Cint cells were recruited after virus infection; coadministration of the ivy extract fraction with oseltamivir reduced infiltration of these inflammatory cells. In a model of suboptimal oseltamivir treatment, coadministration of ivy extract fraction that includes hedrasaponin F increased protection against PR8 infection that could be

Coadministration of Hedera helix L. Extract Enabled Mice to Overcome Insufficient Protection against Influenza A/PR/8 Virus Infection under Suboptimal Treatment with Oseltamivir.

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Eun-Hye Hong

Full Text Available Several anti-influenza drugs that reduce disease manifestation exist, and although these drugs provide clinical benefits in infected patients, their efficacy is limited by the emergence of drug-resistant influenza viruses. In the current study, we assessed the therapeutic strategy of enhancing the antiviral efficacy of an existing neuraminidase inhibitor, oseltamivir, by coadministering with the leaf extract from Hedera helix L, commonly known as ivy. Ivy extract has anti-inflammatory, antibacterial, antifungal, and antihelminthic properties. In the present study, we investigated its potential antiviral properties against influenza A/PR/8 (PR8 virus in a mouse model with suboptimal oseltamivir that mimics a poor clinical response to antiviral drug treatment. Suboptimal oseltamivir resulted in insufficient protection against PR8 infection. Oral administration of ivy extract with suboptimal oseltamivir increased the antiviral activity of oseltamivir. Ivy extract and its compounds, particularly hedrasaponin F, significantly reduced the cytopathic effect in PR8-infected A549 cells in the presence of oseltamivir. Compared with oseltamivir treatment alone, coadministration of the fraction of ivy extract that contained the highest proportion of hedrasaponin F with oseltamivir decreased pulmonary inflammation in PR8-infected mice. Inflammatory cytokines and chemokines, including tumor necrosis factor-alpha and chemokine (C-C motif ligand 2, were reduced by treatment with oseltamivir and the fraction of ivy extract. Analysis of inflammatory cell infiltration in the bronchial alveolar of PR8-infected mice revealed that CD11b+Ly6G+ and CD11b+Ly6Cint cells were recruited after virus infection; coadministration of the ivy extract fraction with oseltamivir reduced infiltration of these inflammatory cells. In a model of suboptimal oseltamivir treatment, coadministration of ivy extract fraction that includes hedrasaponin F increased protection against PR8

Pacific region influenza surveillance for oseltamivir resistance.

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Miller, Heather B; Gose, Remedios B; Nagata, Mark T; Sciulli, Rebecca H; Whelen, A Christian

2012-05-01

Hawaii and the United States-affiliated Pacific islands (USAPI) host over 8 million travelers annually, most of whom originate in Asia, Australia, and the Americas where prevalence of oseltamivir resistance in 2009 pandemic influenza A (H1N1) has been reported to be 2.5-3.5%. To survey a collection of samples from Hawaii and the USAPI that had tested positive for the 2009 pandemic influenza A (H1N1) virus by RTI-PCR to assess whether antiviral resistance emerged in these island communities during the 2009 H1N1 pandemic. We examined RNA extracted from Hawaiian and USAPI cases for the neuraminidase H275Y mutation associated with oseltamivir resistance by pyrosequencing. Two hundred and sixty-three (263) 2009 pandemic influenza A (H1N1) positive specimens were tested and 263/263 (100%) were shown to lack the mutation most commonly associated with oseltamivir resistance. There was no evidence of oseltamivir resistant A(H1N1)pdm09 virus during the 2009 pandemic in the Pacific islands despite considerable travel exposure. Geographic isolation, the lack of a "second wave" of pandemic influenza, judicious antiviral use, aggressive vaccination, and below average tourism due to the global economic crisis may have been contributing factors. Continued surveillance and vigilance is necessary to monitor unpredictable influenza activity. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of neuraminidase inhibitor-resistant mutations on pathogenicity of clade 2.2 A/Turkey/15/06 (H5N1) influenza virus in ferrets.

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Ilyushina, Natalia A; Seiler, Jon P; Rehg, Jerold E; Webster, Robert G; Govorkova, Elena A

2010-05-27

The acquisition of neuraminidase (NA) inhibitor resistance by H5N1 influenza viruses has serious clinical implications, as this class of drugs can be an essential component of pandemic control measures. The continuous evolution of the highly pathogenic H5N1 influenza viruses results in the emergence of natural NA gene variations whose impact on viral fitness and NA inhibitor susceptibility are poorly defined. We generated seven genetically stable recombinant clade 2.2 A/Turkey/15/06-like (H5N1) influenza viruses carrying NA mutations located either in the framework residues (E119A, H274Y, N294S) or in close proximity to the NA enzyme active site (V116A, I117V, K150N, Y252H). NA enzyme inhibition assays showed that NA mutations at positions 116, 117, 274, and 294 reduced susceptibility to oseltamivir carboxylate (IC(50)s increased 5- to 940-fold). Importantly, the E119A NA mutation (previously reported to confer resistance in the N2 NA subtype) was stable in the clade 2.2 H5N1 virus background and induced cross-resistance to oseltamivir carboxylate and zanamivir. We demonstrated that Y252H NA mutation contributed for decreased susceptibility of clade 2.2 H5N1 viruses to oseltamivir carboxylate as compared to clade 1 viruses. The enzyme kinetic parameters (V(max), K(m) and K(i)) of the avian-like N1 NA glycoproteins were highly consistent with their IC(50) values. None of the recombinant H5N1 viruses had attenuated virulence in ferrets inoculated with 10(6) EID(50) dose. Most infected ferrets showed mild clinical disease signs that differed in duration. However, H5N1 viruses carrying the E119A or the N294S NA mutation were lethal to 1 of 3 inoculated animals and were associated with significantly higher virus titers (Pinfluenza drugs that target different virus/host factors and can limit the emergence of resistance.

Brauchen wir die Grippemittel Tamiflu und Relenza?

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Schmidtke, Michaela

2014-08-01

Full Text Available Lately, several press releases as well as a parliamentary inquiry questioned the effectiveness of the neuraminidase inhibitors (NAI, oseltamivir and zanamivir in concerns of therapy of influenza. However, in combination with the unfortunate data communication by the pharma industry after the latest analysis by the Cochrane Collaboration an opinion evolved and was spread supporting the view that the neuraminidase inhibitors are in fact not effective at all.All three scientific expert societies (GfV, DVV and PEG are considering this point illegitimate and also dangerous simplification. On the one hand, the recent analysis by the Cochrane Collaboration confirms a significant reduction in time to first alleviation of symptoms in children (oseltamivir and adults (oseltamivir and zanamivir. On the other hand, due to basic methodical specifications, the analyses of the Cochrane Collaboration does not include any results of observational studies revealing that especially with patients at risk, indeed, there was a positive effect of neuraminidase inhibitors. As long as there is no availability of any better antiviral substances against influenza viruses, the possibility of applying the existing neuraminidase inhibitors must be considered carefully for each respective situation and used for the good of the patients as well.

In vitro neuraminidase inhibitory concentration (IC50) of four neuraminidase inhibitors in the Japanese 2016-17 season: Comparison with the 2010-11 to 2015-16 seasons.

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Ikematsu, Hideyuki; Kawai, Naoki; Iwaki, Norio; Kashiwagi, Seizaburo; Ishikawa, Yusuke; Yamaguchi, Hiroki; Shiosakai, Kazuhito

2018-05-11

To assess the extent of susceptibility to the four most commonly used neuraminidase inhibitors (NAIs) in the viruses epidemic in the 2016-17 Japanese influenza season, we measured the 50% inhibitory concentration (IC 50 ) of these NAIs for influenza virus isolates from patients and compared them with the results from the 2010-11 to 2015-16 seasons. Viral isolation was done with specimens obtained prior to treatment, and the type and subtype was determined by RT-PCR using type- and subtype-specific primers. The IC 50 was determined by a neuraminidase inhibition assay using a fluorescent substrate. A total of 276 virus isolates, 6 A (H1N1)pdm09 (2.2%), 249 A (H3N2) (90.2%), and 21 B (7.6%), had the IC 50 measured for the four NAIs. B isolates included 11 (52.4%), 9 (42.9%), and one (4.8%) of the Victoria, Yamagata, and undetermined strains, respectively. No A (H1N1)pdm09 with highly reduced sensitivity for oseltamivir was found in the 2016-17 season. No isolate with highly reduced sensitivity to the four NAIs have been found for A (H3N2) or B from the 2010-11 to 2016-17 seasons. No significant trend of increase or decrease was found in the geometric mean IC 50 s of the four NAIs during the seven studied seasons. These results indicate that the sensitivity to the four commonly used NAIs has been maintained and that any change in the effectiveness of these NAIs would be minute. Common usage of NAIs for patient treatment has not been a driving force in the selection of NAI resistant viruses. Copyright © 2018 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Assessing the oseltamivir-induced resistance risk and implications for influenza infection control strategies

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Hsieh NH

2017-07-01

Full Text Available Nan-Hung Hsieh,1 Yi-Jun Lin,2 Ying-Fei Yang,2 Chung-Min Liao2 1Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA; 2Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan Background: Oseltamivir-resistant mutants with higher drug resistance rates and low transmission fitness costs have not accounted for influenza (subtype viruses. Predicting the impacts of neuraminidase inhibitor therapy on infection rates and transmission of drug-resistant viral strains requires further investigation.Objectives: The purpose of this study was to assess the potential risk of oseltamivir-induced resistance for influenza A (H1N1 and A (H3N2 viruses.Materials and methods: An immune-response-based virus dynamic model was used to best fit the oseltamivir-resistant A (H1N1 and A (H3N2 infection data. A probabilistic risk assessment model was developed by incorporating branching process-derived probability distribution of resistance to estimate oseltamivir-induced resistance risk.Results: Mutation rate and sensitive strain number were key determinants in assessing resistance risk. By increasing immune response, antiviral efficacy, and fitness cost, the spread of resistant strains for A (H1N1 and A (H3N2 were greatly decreased. Probability of resistance depends most strongly on the sensitive strain number described by a Poisson model. Risk of oseltamivir-induced resistance increased with increasing the mutation rate for A (H1N1 only. The ≥50% of resistance risk induced by A (H1N1 and A (H3N2 sensitive infected cells were 0.4 (95% CI: 0.28–0.43 and 0.95 (95% CI 0.93–0.99 at a mutation rate of 10−6, respectively. Antiviral drugs must be administrated within 1–1.5 days for A (H1N1 and 2–2.5 days for A (H3N2 virus infections to limit viral production.Conclusion: Probabilistic risk assessment of antiviral drug

Competitive fitness of influenza B viruses with neuraminidase inhibitor-resistant substitutions in a coinfection model of the human airway epithelium.

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Burnham, Andrew J; Armstrong, Jianling; Lowen, Anice C; Webster, Robert G; Govorkova, Elena A

2015-04-01

Influenza A and B viruses are human pathogens that are regarded to cause almost equally significant disease burdens. Neuraminidase (NA) inhibitors (NAIs) are the only class of drugs available to treat influenza A and B virus infections, so the development of NAI-resistant viruses with superior fitness is a public health concern. The fitness of NAI-resistant influenza B viruses has not been widely studied. Here we examined the replicative capacity and relative fitness in normal human bronchial epithelial (NHBE) cells of recombinant influenza B/Yamanashi/166/1998 viruses containing a single amino acid substitution in NA generated by reverse genetics (rg) that is associated with NAI resistance. The replication in NHBE cells of viruses with reduced inhibition by oseltamivir (recombinant virus with the E119A mutation generated by reverse genetics [rg-E119A], rg-D198E, rg-I222T, rg-H274Y, rg-N294S, and rg-R371K, N2 numbering) or zanamivir (rg-E119A and rg-R371K) failed to be inhibited by the presence of the respective NAI. In a fluorescence-based assay, detection of rg-E119A was easily masked by the presence of NAI-susceptible virus. We coinfected NHBE cells with NAI-susceptible and -resistant viruses and used next-generation deep sequencing to reveal the order of relative fitness compared to that of recombinant wild-type (WT) virus generated by reverse genetics (rg-WT): rg-H274Y > rg-WT > rg-I222T > rg-N294S > rg-D198E > rg-E119A ≫ rg-R371K. Based on the lack of attenuated replication of rg-E119A in NHBE cells in the presence of oseltamivir or zanamivir and the fitness advantage of rg-H274Y over rg-WT, we emphasize the importance of these substitutions in the NA glycoprotein. Human infections with influenza B viruses carrying the E119A or H274Y substitution could limit the therapeutic options for those infected; the emergence of such viruses should be closely monitored. Influenza B viruses are important human respiratory pathogens contributing to a significant portion

Effect of neuraminidase inhibitor-resistant mutations on pathogenicity of clade 2.2 A/Turkey/15/06 (H5N1 influenza virus in ferrets.

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Natalia A Ilyushina

2010-05-01

Full Text Available The acquisition of neuraminidase (NA inhibitor resistance by H5N1 influenza viruses has serious clinical implications, as this class of drugs can be an essential component of pandemic control measures. The continuous evolution of the highly pathogenic H5N1 influenza viruses results in the emergence of natural NA gene variations whose impact on viral fitness and NA inhibitor susceptibility are poorly defined. We generated seven genetically stable recombinant clade 2.2 A/Turkey/15/06-like (H5N1 influenza viruses carrying NA mutations located either in the framework residues (E119A, H274Y, N294S or in close proximity to the NA enzyme active site (V116A, I117V, K150N, Y252H. NA enzyme inhibition assays showed that NA mutations at positions 116, 117, 274, and 294 reduced susceptibility to oseltamivir carboxylate (IC(50s increased 5- to 940-fold. Importantly, the E119A NA mutation (previously reported to confer resistance in the N2 NA subtype was stable in the clade 2.2 H5N1 virus background and induced cross-resistance to oseltamivir carboxylate and zanamivir. We demonstrated that Y252H NA mutation contributed for decreased susceptibility of clade 2.2 H5N1 viruses to oseltamivir carboxylate as compared to clade 1 viruses. The enzyme kinetic parameters (V(max, K(m and K(i of the avian-like N1 NA glycoproteins were highly consistent with their IC(50 values. None of the recombinant H5N1 viruses had attenuated virulence in ferrets inoculated with 10(6 EID(50 dose. Most infected ferrets showed mild clinical disease signs that differed in duration. However, H5N1 viruses carrying the E119A or the N294S NA mutation were lethal to 1 of 3 inoculated animals and were associated with significantly higher virus titers (P<0.01 and inflammation in the lungs compared to the wild-type virus. Our results suggest that highly pathogenic H5N1 variants carrying mutations within the NA active site that decrease susceptibility to NA inhibitors may possess increased

Bench to Bed Evidences for Pharmacokinetic and Pharmacodynamic Interactions Involving Oseltamivir and Chinese Medicine

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Qi Chang

2014-01-01

Full Text Available Oseltamivir (OA, an ethyl ester prodrug of oseltamivir carboxylate (OC, is clinically used as a potent and selective inhibitor of neuraminidase. Chinese medicines have been advocated to combine with conventional drug for avian influenza. The current study aims to investigate the potential pharmacokinetic and pharmacodynamic interactions of a Chinese medicine formula, namely, Yin Qiao San and Sang Ju Yin (CMF1, commonly used for anti-influenza in combination with OA in both rat and human, and to reveal the underlined mechanisms. It was found that although Cmax, AUC and urinary recovery of OC, as well as metabolic ratio (AUCOC/AUCOA, were significantly decreased in a dose-dependent manner following combination use of CMF1 and OA in rat studies (P<0.01, such coadministration in 14 healthy volunteers only resulted in a trend of minor decrease in the related parameters. Further mechanistic studies found that although CMF1 could reduce absorption and metabolism of OA, it appears to enhance viral inhibition of OA (P<0.01. In summary, although there was potential interaction between OA and CMF1 found in rat studies, its clinical impact was expected to be minimal. The coadministration of OA and CMF1 at the clinical recommended dosages is, therefore, considered to be safe.

Iota-carrageenan is a potent inhibitor of influenza A virus infection.

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Andreas Leibbrandt

Full Text Available The 2009 flu pandemic and the appearance of oseltamivir-resistant H1N1 influenza strains highlight the need for treatment alternatives. One such option is the creation of a protective physical barrier in the nasal cavity. In vitro tests demonstrated that iota-carrageenan is a potent inhibitor of influenza A virus infection, most importantly also of pandemic H1N1/2009 in vitro. Consequently, we tested a commercially available nasal spray containing iota-carrageenan in an influenza A mouse infection model. Treatment of mice infected with a lethal dose of influenza A PR8/34 H1N1 virus with iota-carrageenan starting up to 48 hours post infection resulted in a strong protection of mice similar to mice treated with oseltamivir. Since alternative treatment options for influenza are rare, we conclude that the nasal spray containing iota-carrageenan is an alternative to neuraminidase inhibitors and should be tested for prevention and treatment of influenza A in clinical trials in humans.

Drug susceptibility of influenza A/H3N2 strains co-circulating during 2009 influenza pandemic: first report from Mumbai.

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Gohil, Devanshi J; Kothari, Sweta T; Shinde, Pramod S; Chintakrindi, Anand S; Meharunkar, Rhuta; Warke, Rajas V; Kanyalkar, Meena A; Chowdhary, Abhay S; Deshmukh, Ranjana A

2015-01-01

From its first instance in 1977, resistance to amantadine, a matrix (M2) inhibitor has been increasing among influenza A/H3N2, thus propelling the use of oseltamivir, a neuraminidase (NA) inhibitor as a next line drug. Information on drug susceptibility to amantadine and neuraminidase inhibitors for influenza A/H3N2 viruses in India is limited with no published data from Mumbai. This study aimed at examining the sensitivity to M2 and NA inhibitors of influenza A/H3N2 strains isolated from 2009 to 2011 in Mumbai. Nasopharyngeal swabs positive for influenza A/H3N2 virus were inoculated on Madin-Darby canine kidney (MDCK) cell line for virus isolation. Molecular analysis of NA and M2 genes was used to detect known mutations contributing to resistance. Resistance to neuraminidase was assayed using a commercially available chemiluminescence based NA-Star assay kit. Genotypically, all isolates were observed to harbor mutations known to confer resistance to amantadine. However, no know mutations conferring resistance to NA inhibitors were detected. The mean IC50 value for oseltamivir was 0.25 nM. One strain with reduced susceptibility to the neuraminidase inhibitor (IC₅₀=4.08 nM) was isolated from a patient who had received oseltamivir treatment. Phylogenetic analysis postulate the emergence of amantadine resistance in Mumbai may be due to genetic reassortment with the strains circulating in Asia and North America. Surveillance of drug susceptibility helped us to identify an isolate with reduced sensitivity to oseltamivir. Therefore, we infer that such surveillance would help in understanding possible trends underlying the emergence of resistant variants in humans. Copyright © 2014 Elsevier B.V. All rights reserved.

Financial conflicts of interest and conclusions about neuraminidase inhibitors for influenza: an analysis of systematic reviews.

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Dunn, Adam G; Arachi, Diana; Hudgins, Joel; Tsafnat, Guy; Coiera, Enrico; Bourgeois, Florence T

2014-10-07

Industry funding and financial conflicts of interest may contribute to bias in the synthesis and interpretation of scientific evidence. To examine the association between financial conflicts of interest and characteristics of systematic reviews of neuraminidase inhibitors. Retrospective analysis. Reviews that examined the use of neuraminidase inhibitors in the prophylaxis or treatment of influenza, were published between January 2005 and May 2014, and used a systematic search protocol. Two investigators blinded to all information regarding the review authors independently assessed the presentation of evidence on the use of neuraminidase inhibitors as favorable or not favorable. Financial conflicts of interest were identified using the index reviews, other publications, and Web-based searches. Associations between financial conflicts of interest, favorability assessments, and presence of critical appraisals of evidence quality were analyzed. Twenty-six systematic reviews were identified, of which 13 examined prophylaxis and 24 examined treatment, accounting for 37 distinct assessments. Among assessments associated with a financial conflict of interest, 7 of 8 (88%) were classified as favorable, compared with 5 of 29 (17%) among those without a financial conflict of interest. Reviewers without financial conflicts of interest were more likely to include statements about the quality of the primary studies than those with financial conflicts of interest. The heterogeneity in populations and outcomes examined in the reviews precluded analysis of the contribution of selective inclusion of evidence on the discordance of the assessments made in the reviews. Many of the systematic reviews had overlapping authorship. Reviewers with financial conflicts of interest may be more likely to present evidence about neuraminidase inhibitors in a favorable manner and recommend the use of these drugs than reviewers without financial conflicts of interest. Australian National Health and

Prognosis of hospitalized patients with 2009 H1N1 influenza in Spain: influence of neuraminidase inhibitors

Science.gov (United States)

Delgado-Rodríguez, Miguel; Castilla, Jesús; Godoy, Pere; Martín, Vicente; Soldevila, Nuria; Alonso, Jordi; Astray, Jenaro; Baricot, Maretva; Cantón, Rafael; Castro, Ady; Gónzález-Candelas, Fernando; Mayoral, José María; Quintana, José María; Pumarola, Tomás; Tamames, Sonia; Sáez, Marc; Domínguez, Angela

2012-01-01

Background The H1N1 influenza pandemic strain has been associated with a poor prognosis in hospitalized patients. The present report evaluates the factors influencing prognosis. Methods A total of 813 patients hospitalized with H1N1 influenza in 36 hospitals (nationwide) in Spain were analysed. Detailed histories of variables preceding hospital admission were obtained by interview, validating data on medications and vaccine with their attending physicians. Data on treatment and complications during hospital stay were recorded. As definition of poor outcome, the endpoints of death and admission to intensive care were combined; and as a further outcome, length of stay was used. Results The mean age was 38.5 years (SD 22.8 years). There were 10 deaths and 79 admissions to intensive care (combined, 88). The use of neuraminidase inhibitors was reported by 495 patients (60.9%). The variables significantly associated with a poor outcome were diabetes (OR = 2.21, 95% CI = 1.21–4.02), corticosteroid therapy (OR = 3.37, 95% CI = 1.39–8.20) and use of histamine-2 receptor antagonists (OR = 2.68, 95% CI = 1.14–6.36), while the use of neuraminidase inhibitors (OR = 0.57, 95% CI = 0.34–0.94) was protective. Neuraminidase inhibitors within the first 2 days after the influenza onset reduced hospital stay by a mean of 1.9 days (95% CI = 4.7–6.6). Conclusions The use of neuraminidase inhibitors decreases the length of hospital stay and admission to intensive care and/or death. PMID:22467633

Antiviral Resistance to Influenza Viruses: Clinical and Epidemiological Aspects

NARCIS (Netherlands)

van der Vries, E.

2017-01-01

There are three classes of antiviral drugs approved for the treatment of influenza: the M2 ion channel inhibitors (amantadine, rimantadine), neuraminidase (NA) inhibitors (laninamivir, oseltamivir, peramivir, zanamivir), and the protease inhibitor (favipiravir); some of the agents are only available

Unique Determinants of Neuraminidase Inhibitor Resistance among N3, N7, and N9 Avian Influenza Viruses.

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Song, Min-Suk; Marathe, Bindumadhav M; Kumar, Gyanendra; Wong, Sook-San; Rubrum, Adam; Zanin, Mark; Choi, Young-Ki; Webster, Robert G; Govorkova, Elena A; Webby, Richard J

2015-11-01

Human infections with avian influenza viruses are a serious public health concern. The neuraminidase (NA) inhibitors (NAIs) are the frontline anti-influenza drugs and are the major option for treatment of newly emerging influenza. Therefore, it is essential to identify the molecular markers of NAI resistance among specific NA subtypes of avian influenza viruses to help guide clinical management. NAI-resistant substitutions in NA subtypes other than N1 and N2 have been poorly studied. Here, we identified NA amino acid substitutions associated with NAI resistance among influenza viruses of N3, N7, and N9 subtypes which have been associated with zoonotic transmission. We applied random mutagenesis and generated recombinant influenza viruses carrying single or double NA substitution(s) with seven internal genes from A/Puerto Rico/8/1934 (H1N1) virus. In a fluorescence-based NA inhibition assay, we identified three categories of NA substitutions associated with reduced inhibition by NAIs (oseltamivir, zanamivir, and peramivir): (i) novel subtype-specific substitutions in or near the enzyme catalytic site (R152W, A246T, and D293N, N2 numbering), (ii) subtype-independent substitutions (E119G/V and/or D and R292K), and (iii) substitutions previously reported in other subtypes (Q136K, I222M, and E276D). Our data show that although some markers of resistance are present across NA subtypes, other subtype-specific markers can only be determined empirically. The number of humans infected with avian influenza viruses is increasing, raising concerns of the emergence of avian influenza viruses resistant to neuraminidase (NA) inhibitors (NAIs). Since most studies have focused on NAI-resistance in human influenza viruses, we investigated the molecular changes in NA that could confer NAI resistance in avian viruses grown in immortalized monolayer cells, especially those of the N3, N7, and N9 subtypes, which have caused human infections. We identified not only numerous NAI

Effectiveness of neuraminidase inhibitors for preventing staff absenteeism during pandemic influenza

OpenAIRE

Lee, VJ; Chen, MI

2007-01-01

We used a deterministic SEIR (susceptible-exposed-infectious-removed) meta-population model, together with scenario, sensitivity, and simulation analyses, to determine stockpiling strategies for neuraminidase inhibitors that would minimize absenteeism among healthcare workers. A pandemic with a basic reproductive number (R0) of 2.5 resulted in peak absenteeism of 10%. Treatment decreased peak absenteeism to 8%, while 8 weeks' prophylaxis reduced it to 2%. For pandemics with higher R0, peak ab...

Genetic makeup of amantadine-resistant and oseltamivir-resistant human influenza A/H1N1 viruses.

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Zaraket, Hassan; Saito, Reiko; Suzuki, Yasushi; Baranovich, Tatiana; Dapat, Clyde; Caperig-Dapat, Isolde; Suzuki, Hiroshi

2010-04-01

The emergence and widespread occurrence of antiviral drug-resistant seasonal human influenza A viruses, especially oseltamivir-resistant A/H1N1 virus, are major concerns. To understand the genetic background of antiviral drug-resistant A/H1N1 viruses, we performed full genome sequencing of prepandemic A/H1N1 strains. Seasonal influenza A/H1N1 viruses, including antiviral-susceptible viruses, amantadine-resistant viruses, and oseltamivir-resistant viruses, obtained from several areas in Japan during the 2007-2008 and 2008-2009 influenza seasons were analyzed. Sequencing of the full genomes of these viruses was performed, and the phylogenetic relationships among the sequences of each individual genome segment were inferred. Reference genome sequences from the Influenza Virus Resource database were included to determine the closest ancestor for each segment. Phylogenetic analysis revealed that the oseltamivir-resistant strain evolved from a reassortant oseltamivir-susceptible strain (clade 2B) which circulated in the 2007-2008 season by acquiring the H275Y resistance-conferring mutation in the NA gene. The oseltamivir-resistant lineage (corresponding to the Northern European resistant lineage) represented 100% of the H1N1 isolates from the 2008-2009 season and further acquired at least one mutation in each of the polymerase basic protein 2 (PB2), polymerase basic protein 1 (PB1), hemagglutinin (HA), and neuraminidase (NA) genes. Therefore, a reassortment event involving two distinct oseltamivir-susceptible lineages, followed by the H275Y substitution in the NA gene and other mutations elsewhere in the genome, contributed to the emergence of the oseltamivir-resistant lineage. In contrast, amantadine-resistant viruses from the 2007-2008 season distinctly clustered in clade 2C and were characterized by extensive amino acid substitutions across their genomes, suggesting that a fitness gap among its genetic components might have driven these mutations to maintain it in the

Kinetic, thermodynamic and structural analysis of tamiphosphor binding to neuraminidase of H1N1 (2009) pandemic influenza

Czech Academy of Sciences Publication Activity Database

Albinana, C. B.; Machara, A.; Řezáčová, Pavlína; Pachl, P.; Konvalinka, J.; Kožíšek, M.

2016-01-01

Roč. 121, OCT 4 (2016), s. 100-109 ISSN 0223-5234 R&D Projects: GA ČR GA13-19561S; GA MŠk LO1302; GA MŠk(CZ) LO1304 Institutional support: RVO:68378050 Keywords : Influenza neuraminidase * Oseltamivir * Tamiphosphor * Isothermal titration calorimetry * Crystal structure * Lattice-translocation defect Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.519, year: 2016

Kinetic, thermodynamic and structural analysis of tamiphosphor binding to neuraminidase of H1N1 (2009) pandemic influenza

Czech Academy of Sciences Publication Activity Database

Albinana, C. B.; Machara, A.; Řezáčová, Pavlína; Pachl, Petr; Konvalinka, Jan; Kožíšek, Milan

2016-01-01

Roč. 121, Oct 4 (2016), s. 100-109 ISSN 0223-5234 R&D Projects: GA ČR GA13-19561S; GA MŠk LO1302; GA MŠk(CZ) LO1304 Institutional support: RVO:61388963 Keywords : influenza neuraminidase * oseltamivir * tamiphosphor * isothermal titration calorimetry * crystal structure * lattice-translocation defect Subject RIV: CE - Biochemistry Impact factor: 4.519, year: 2016

Influenza neuraminidase: a druggable target for natural products.

Science.gov (United States)

Grienke, Ulrike; Schmidtke, Michaela; von Grafenstein, Susanne; Kirchmair, Johannes; Liedl, Klaus R; Rollinger, Judith M

2012-01-01

The imminent threat of influenza pandemics and repeatedly reported emergence of new drug-resistant influenza virus strains demonstrate the urgent need for developing innovative and effective antiviral agents for prevention and treatment. At present, influenza neuraminidase (NA), a key enzyme in viral replication, spread, and pathogenesis, is considered to be one of the most promising targets for combating influenza. Despite the substantial medical potential of NA inhibitors (NAIs), only three of these drugs are currently on the market (zanamivir, oseltamivir, and peramivir). Moreover, sudden changes in NAI susceptibility revealed the urgent need in the discovery/identification of novel inhibitors. Nature offers an abundance of biosynthesized compounds comprising chemical scaffolds of high diversity, which present an infinite pool of chemical entities for target-oriented drug discovery in the battle against this highly contagious pathogen. This review illuminates the increasing research efforts of the past decade (2000-2011), focusing on the structure, function and druggability of influenza NA, as well as its inhibition by natural products. Following a critical discussion of publications describing some 150 secondary plant metabolites tested for their inhibitory potential against influenza NA, the impact of three different strategies to identify and develop novel NAIs is presented: (i) bioactivity screening of herbal extracts, (ii) exploitation of empirical knowledge, and (iii) computational approaches. This work addresses the latest developments in theoretical and experimental research on properties of NA that are and will be driving anti-influenza drug development now and in the near future.

Effects of dexamethasone coadministered with oseltamivir on the pharmacokinetics of oseltamivir in healthy volunteers

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Jang K

2017-03-01

Full Text Available Kyungho Jang,1,2,* Min-Kyoung Kim,3,4,* Jaeseong Oh,1 SeungHwan Lee,1 Joo-Youn Cho,1 Kyung-Sang Yu,1 Tai Kiu Choi,3 Sang-Hyuk Lee,3,4 Kyoung Soo Lim4 1Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, 2Center for Clinical Pharmacology and Biomedical Research Institute, Chonbuk National University Medical School, Jeonju, 3Department of Psychiatry, 4Department of Clinical Pharmacology and Therapeutics, CHA University School of Medicine and CHA Bundang Medical Center, Seongnam, Republic of Korea *These authors contributed equally to this work Purpose: Oseltamivir is widely used in the treatment and prophylaxis of influenza A and B viral infections. It is ingested as an oral prodrug that is rapidly metabolized by carboxylesterase 1 (CES1 to its active form, oseltamivir carboxylate. Dexamethasone is also used in the treatment of acute respiratory distress syndrome, a severe complication of influenza; however, its influence on the pharmacokinetics (PK of oseltamivir is controversial. The aim of this study was to investigate the effects of coadministering oseltamivir and dexamethasone on the PK of oseltamivir in healthy volunteers. Methods: An open-label, two-period, one-sequence, multiple-dose study was conducted in 19 healthy male volunteers. Oseltamivir (75 mg was orally administered on Day 1 and Day 8, and dexamethasone (1.5 mg was administered once daily from Day 3 to Day 8. Serial blood and urine samples were collected for PK analysis of oseltamivir and oseltamivir carboxylate on Day 1 and Day 8. Oseltamivir and oseltamivir carboxylate concentrations in plasma and urine were determined using liquid chromatography–tandem mass spectrometry. Results: Area under the plasma concentration–time curve (AUC of oseltamivir and oseltamivir carboxylate decreased after dexamethasone treatment for 6 days. The geometric mean ratio (90% confidence interval of the metabolic ratio

Neuraminidase inhibitors in the treatment and post exposure prevention of influenza

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von der Schulenburg, Johann-Matthias

2006-01-01

Full Text Available Introduction: Influenza is a viral respiratory infection which presents itself as an acute febrile disease. It is contracted by virus-laden respiratory secretions from infected individuals. Symptoms usually last three to seven days and are accompanied by severely limited activities during this time. A definite diagnosis, however, can only be made by laboratory analysis. Every year, about 20% of children and 5% of adults develop symptomatic influenza of the serotypes A or B worldwide. Typical complications of influenza include viral or bacterial infections, as well as deterioration of an existing cardio-vascular or respiratory disease which may lead to hospitalization and death. Current policy recommends that individuals, who are at-risk of developing serious complications (patients over sixty years of age or patients with concomitant chronic diseases, as well as people in direct contact with high risk patients (i.e. nursing staff in living and care facilities, should be annually vaccinated with inactivated influenza strains. Various pharmaceutical agents for the treatment and prophylaxis of influenza have been approved. Amantadine, which inhibits the viral M2-ion channel, is only effective in influenza-serotype A. Neuraminidase inhibitors (NI represent a new class of antivirals for prophylaxis and treatment of influenza A and B. NI interrupt various central functions that are vital for the life cycle and spreading of the virus. Two drugs of this substance class, Zanamivir (RelenzaTM and Oseltamivir (Tamiflu®, are licensed for the treatment of influenza. For adults and teenagers over thirteen years of age Oseltamivir is also approved for the prophylaxis of influenza. Zanamivir is a powder which needs to be inhaled, whereas Oseltamivir is licensed as a capsule for oral administration. M2-inhibitors and NI are only effective at an early stage of the influenza infection, i.e. during the first 36 to 48 hours after symptom onset, before replication

Oseltamivir resistance among influenza viruses: surveillance in northern Viet Nam, 2009-2012.

Science.gov (United States)

Hoang Vu, Mai-Phuong; Nguyen, Co Thach; Nguyen, Le Khanh Hang; Nguyen, Thi Kim Phuong; Le, Quynh Mai

2013-01-01

Antiviral resistance has been reported in seasonal influenza A viruses and avian influenza A(H5N1) viruses in Viet Nam, raising concerns about the efficacy of treatment. We analysed specimens from two sources during the period 2009-2012: influenza-positive samples from influenza-like illness patients at sentinel clinics in northern Viet Nam and isolates from patients with confirmed A(H5N1) infections. Pyrosequencing was used to detect mutations: H275Y [for A(H1N1) and A(H5N1)], E119V [for A(H3N2)] and I117V [for A(H5N1)]. A neuraminidase inhibition assay was used to determine the Inhibitory Concentration 50 (IC₅₀) values for all influenza A and B isolates. There were 341 influenza A positive samples identified; influenza A(H1N1)pdm09 was identified most frequently (n = 215). In 2009, oseltamivir resistance was observed in 100% (19 of 19) of seasonal A(H1N1) isolates and 1.4% (3/215) of A(H1N1)pdm09 isolates. This H275Y mutation was not found in influenza subtypes A(H5N1) or A(H3N2) isolates. In Viet Nam, seasonal and A(H5N1) influenza vaccines are not currently available; thus, effective treatment is required. The presence of oseltamivir-resistant viruses is therefore a concern. Active surveillance for oseltamivir resistance among influenza viruses circulating in Viet Nam should be continued.

Multidrug resistant 2009 A/H1N1 influenza clinical isolate with a neuraminidase I223R mutation retains its virulence and transmissibility in ferrets.

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Erhard van der Vries

2011-09-01

Full Text Available Only two classes of antiviral drugs, neuraminidase inhibitors and adamantanes, are approved for prophylaxis and therapy against influenza virus infections. A major concern is that influenza virus becomes resistant to these antiviral drugs and spreads in the human population. The 2009 pandemic A/H1N1 influenza virus is naturally resistant to adamantanes. Recently a novel neuraminidase I223R mutation was identified in an A/H1N1 virus showing cross-resistance to the neuraminidase inhibitors oseltamivir, zanamivir and peramivir. However, the ability of this virus to cause disease and spread in the human population is unknown. Therefore, this clinical isolate (NL/2631-R223 was compared with a well-characterized reference virus (NL/602. In vitro experiments showed that NL/2631-I223R replicated as well as NL/602 in MDCK cells. In a ferret pathogenesis model, body weight loss was similar in animals inoculated with NL/2631-R223 or NL/602. In addition, pulmonary lesions were similar at day 4 post inoculation. However, at day 7 post inoculation, NL/2631-R223 caused milder pulmonary lesions and degree of alveolitis than NL/602. This indicated that the mutant virus was less pathogenic. Both NL/2631-R223 and a recombinant virus with a single I223R change (recNL/602-I223R, transmitted among ferrets by aerosols, despite observed attenuation of recNL/602-I223R in vitro. In conclusion, the I223R mutated virus isolate has comparable replicative ability and transmissibility, but lower pathogenicity than the reference virus based on these in vivo studies. This implies that the 2009 pandemic influenza A/H1N1 virus subtype with an isoleucine to arginine change at position 223 in the neuraminidase has the potential to spread in the human population. It is important to be vigilant for this mutation in influenza surveillance and to continue efforts to increase the arsenal of antiviral drugs to combat influenza.

Curcuminoids from Curcuma longa and their inhibitory activities on influenza A neuraminidases

DEFF Research Database (Denmark)

Dao, Trong Tuan; Won, Ho Keun; Kim, Eun Hee

2012-01-01

The emergence of drug-resistant influenza viruses and the threat of pandemics highlight the need for new and effective antiviral agents. In this study, we describe the isolation of 3 new (1–3) and 10 known (4−13) curcuminoids from a methanol extract of Curcuma longa L. All compounds had strong...... against the neuraminidases from novel influenza H1N1 (WT) and oseltamivir-resistant novel H1N1 (H274Y mutant) expressed in 293T cells. Our results suggest that the curcuminoids from C. longa may be potential supplemental molecules in the prevention and treatment of disease by influenza viruses....

AVALIAÇÃO DO TRATAMENTO REALIZADO COM O ANTIVIRAL FOSFATO DE OSELTAMIVIR (TAMIFLU® E OS EXAMES LABORATORIAIS DE PACIENTES DIAGNOSTICADOS COM GRIPE A SUBTIPO H1N1 EM UM HOSPITAL DA CIDADE DE TOLEDO – PARANÁ, BRASIL

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Kiara Regina Canzi

2015-12-01

Full Text Available O fosfato de oseltamivir, uma pró-droga do carboxilato de oseltamivir, é um inibidor potente e seletivo das enzimas neuraminidase. A atividade da enzima viral, neuraminidase, é importante tanto para a entrada do vírus em células não infectadas quanto para a liberação de partículas virais. O carboxilato de oseltamivir inibe a neuraminidase do vírus da gripe de ambos os tipos: Influenza A e B, impedindo a replicação do mesmo. 46 pacientes com idades entre 1 e 76 anos de idade, de ambos os sexos, internados em um Hospital na cidade de Toledo durante o período de Junho de 2009 a Janeiro de 2010, com casos confirmados ou suspeitos de gripe A subtipo H1N1. Durante o período de internamento, foi avaliado o uso do Fosfato de Oseltamivir, bem como reações adversas e tempo de uso do medicamento e os exames empregados para auxiliar o diagnóstico (Hemograma completo e a gasometria arterial. O tempo de uso do medicamento não excedeu o preconizado, o qual foi de 5 (cinco dias ininterruptos, e entre as reações adversas ou efeitos colaterais estão náusea (43,47%, cefaléia (8,69% e vômitos (17,39%. As alterações laboratoriais evidenciam leucócitos normais (média de 9.145 mL, plaquetas de 246.166 mm³, pH sanguíneo (gasometria arterial levemente ácido e PO2 (mmHg e SO2 abaixo dos valores de referência. A abordagem da infecção pelo vírus Influenza A H1N1 2009 representa desafio epidemiológico-clinico-laboratorial-terapêutico em todo o mundo. Logo, requer esforço coletivo para impedir o seu avanço e os riscos de letalidade e mortalidade incluídos em sua disseminação.

Parallel screening of wild-type and drug-resistant targets for anti-resistance neuraminidase inhibitors.

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Kai-Cheng Hsu

Full Text Available Infection with influenza virus is a major public health problem, causing serious illness and death each year. Emergence of drug-resistant influenza virus strains limits the effectiveness of drug treatment. Importantly, a dual H275Y/I223R mutation detected in the pandemic influenza A 2009 virus strain results in multidrug resistance to current neuraminidase (NA drugs. Therefore, discovery of new agents for treating multiple drug-resistant (MDR influenza virus infections is important. Here, we propose a parallel screening strategy that simultaneously screens wild-type (WT and MDR NAs, and identifies inhibitors matching the subsite characteristics of both NA-binding sites. These may maintain their potency when drug-resistant mutations arise. Initially, we analyzed the subsite of the dual H275Y/I223R NA mutant. Analysis of the site-moiety maps of NA protein structures show that the mutant subsite has a relatively small volume and is highly polar compared with the WT subsite. Moreover, the mutant subsite has a high preference for forming hydrogen-bonding interactions with polar moieties. These changes may drive multidrug resistance. Using this strategy, we identified a new inhibitor, Remazol Brilliant Blue R (RB19, an anthraquinone dye, which inhibited WT NA and MDR NA with IC(50 values of 3.4 and 4.5 µM, respectively. RB19 comprises a rigid core scaffold and a flexible chain with a large polar moiety. The former interacts with highly conserved residues, decreasing the probability of resistance. The latter forms van der Waals contacts with the WT subsite and yields hydrogen bonds with the mutant subsite by switching the orientation of its flexible side chain. Both scaffolds of RB19 are good starting points for lead optimization. The results reveal a parallel screening strategy for identifying resistance mechanisms and discovering anti-resistance neuraminidase inhibitors. We believe that this strategy may be applied to other diseases with high

A cluster of patients infected with I221V influenza b virus variants with reduced oseltamivir susceptibility--North Carolina and South Carolina, 2010-2011.

Science.gov (United States)

Garg, Shikha; Moore, Zack; Lee, Nicole; McKenna, John; Bishop, Amber; Fleischauer, Aaron; Springs, Chasisity B; Nguyen, Ha T; Sheu, Tiffany G; Sleeman, Katrina; Finelli, Lyn; Gubareva, Larisa; Fry, Alicia M

2013-03-15

During 2010-2011, influenza B viruses with a novel neuraminidase substitution, denoted I221V (B/I221V), associated with reduced in vitro oseltamivir susceptibility were detected in North Carolina. We determined the prevalence of I221V among B viruses submitted to the Centers for Disease Control and Prevention for antiviral resistance surveillance, including all B viruses submitted to North Carolina and South Carolina state laboratories, during October 2010-September 2011.We conducted chart reviews and telephone interviews to characterize North Carolina and South Carolina patients with B/I221V vs wild-type B virus infection (B/WT). We detected I221V in 45 (22%) of 209 B viruses from North Carolina and 8 (10%) of 82 B viruses from South Carolina. We detected I221V in 3 (0.3%) of 881 B viruses tested from 45 other states. B/I221V infection was not associated with differences in underlying conditions or illness severity, compared with B/WT infection. No patients with B/I221V infection received oseltamivir prior to specimen collection. Among patients who completed oseltamivir, those with B/I221V infection reported a longer duration until illness resolution (5 vs 3 days; P = .02). B/I221V cocirculated with B/WT in North Carolina and South Carolina during 2010-2011. I221V did not alter illness severity but may have reduced oseltamivir effectiveness. Thus, global surveillance for I221V is important.

Published sequences do not support transfer of oseltamivir resistance mutations from avian to human influenza A virus strains.

Science.gov (United States)

Norberg, Peter; Lindh, Magnus; Olofsson, Sigvard

2015-03-28

Tamiflu (oseltamivir phosphate ester, OE) is a widely used antiviral active against influenza A virus. Its active metabolite, oseltamivir carboxylate (OC), is chemically stable and secreted into wastewater treatment plants. OC contamination of natural habitats of waterfowl might induce OC resistance in influenza viruses persistently infecting waterfowl, and lead to transfer of OC-resistance from avian to human influenza. The aim of this study was to evaluate whether such has occurred. A genomics approach including phylogenetic analysis and probability calculations for homologous recombination was applied on altogether 19,755 neuraminidase (N1 and N2) genes from virus sampled in humans and birds, with and without resistance mutations. No evidence for transfer of OE resistance mutations from avian to human N genes was obtained, and events suggesting recombination between human and avian influenza virus variants could not be traced in the sequence material studied. The results indicate that resistance in influenza viruses infecting humans is due to the selection pressure posed by the global OE administration in humans rather than transfer from avian influenza A virus strains carrying mutations induced by environmental exposure to OC.

Discovery of potential drugs for human-infecting H7N9 virus containing R294K mutation

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He JY

2014-12-01

Full Text Available Jiao-Yu He,1,* Cheng Li,2,* Guo Wu3 1College of Life Sciences and Key Laboratory for Bio-resources of Ministry of Education, Sichuan University, 2College of Agronomy, Sichuan Agricultural University, 3College of Life Sciences, Sichuan Normal University, Chengdu, People’s Republic of China *These authors contributed equally to this work Background: After the first epidemic wave from February through May 2013, the influenza A (H7N9 virus emerged and has followed a second epidemic wave since June 2013. As of June 27, 2014, the outbreak of H7N9 had caused 450 confirmed cases of human infection, with 165 deaths included. The case-fatality rate of all confirmed cases is about 36%, making the H7N9 virus a significant threat to people’s health. At present, neuraminidase inhibitors are the only licensed antiviral medications available to treat H7N9 infections in humans. Oseltamivir is the most commonly used inhibitor, and it is also a front-line drug for the threatening H7N9. Unfortunately, it has been reported that patients treated with oseltamivir can induce R294K (Arg294Lys substitution in the H7N9 virus, which is a rare mutation and can reduce the antiviral efficacy of inhibitors. Even worse, deaths caused by such mutation after oseltamivir treatment have already been reported, indicating that the need to find substitutive neuraminidase inhibitors for currently available drugs to treat drug-resistant H7N9 is really pressing.Materials and methods: First, the structure of H7N9 containing the R294K substitution was downloaded from the Protein Data Bank, and structural information of approved drugs was downloaded from the ZINC (ZINC Is Not Commercial database. Taking oseltamivir carboxylate as a reference drug, we then filtered these molecules through virtual screening to find out potential inhibitors targeting the mutated H7N9 virus. For further evaluation, we carried out a 14 ns molecular dynamic simulation for each H7N9–drug complex and

Reassortment and mutations associated with emergence and spread of oseltamivir-resistant seasonal influenza A/H1N1 viruses in 2005-2009.

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Ji-Rong Yang

Full Text Available A dramatic increase in the frequency of the H275Y mutation in the neuraminidase (NA, conferring resistance to oseltamivir, has been detected in human seasonal influenza A/H1N1 viruses since the influenza season of 2007-2008. The resistant viruses emerged in the ratio of 14.3% and quickly reached 100% in Taiwan from September to December 2008. To explore the mechanisms responsible for emergence and spread of the resistant viruses, we analyzed the complete genome sequences of 25 viruses collected during 2005-2009 in Taiwan, which were chosen from various clade viruses, 1, 2A, 2B-1, 2B-2, 2C-1 and 2C-2 by the classification of hemagglutinin (HA sequences. Our data revealed that the dominant variant, clade 2B-1, in the 2007-2008 influenza emerged through an intra-subtype 4+4 reassortment between clade 1 and 2 viruses. The dominant variant acquired additional substitutions, including A206T in HA, H275Y and D354G in NA, L30R and H41P in PB1-F2, and V411I and P453S in basic polymerase 2 (PB2 proteins and subsequently caused the 2008-2009 influenza epidemic in Taiwan, accompanying the widespread oseltamivir-resistant viruses. We also characterized another 3+5 reassortant virus which became double resistant to oseltamivir and amantadine. Comparison of oseltamivir-resistant influenza A/H1N1 viruses belonging to various clades in our study highlighted that both reassortment and mutations were associated with emergence and spread of these viruses and the specific mutation, H275Y, conferring to antiviral resistance, was acquired in a hitch-hiking mechanism during the viral evolutionary processes.

Low dose influenza virus challenge in the ferret leads to increased virus shedding and greater sensitivity to oseltamivir.

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Marriott, Anthony C; Dove, Brian K; Whittaker, Catherine J; Bruce, Christine; Ryan, Kathryn A; Bean, Thomas J; Rayner, Emma; Pearson, Geoff; Taylor, Irene; Dowall, Stuart; Plank, Jenna; Newman, Edmund; Barclay, Wendy S; Dimmock, Nigel J; Easton, Andrew J; Hallis, Bassam; Silman, Nigel J; Carroll, Miles W

2014-01-01

Ferrets are widely used to study human influenza virus infection. Their airway physiology and cell receptor distribution makes them ideal for the analysis of pathogenesis and virus transmission, and for testing the efficacy of anti-influenza interventions and vaccines. The 2009 pandemic influenza virus (H1N1pdm09) induces mild to moderate respiratory disease in infected ferrets, following inoculation with 106 plaque-forming units (pfu) of virus. We have demonstrated that reducing the challenge dose to 102 pfu delays the onset of clinical signs by 1 day, and results in a modest reduction in clinical signs, and a less rapid nasal cavity innate immune response. There was also a delay in virus production in the upper respiratory tract, this was up to 9-fold greater and virus shedding was prolonged. Progression of infection to the lower respiratory tract was not noticeably delayed by the reduction in virus challenge. A dose of 104 pfu gave an infection that was intermediate between those of the 106 pfu and 102 pfu doses. To address the hypothesis that using a more authentic low challenge dose would facilitate a more sensitive model for antiviral efficacy, we used the well-known neuraminidase inhibitor, oseltamivir. Oseltamivir-treated and untreated ferrets were challenged with high (106 pfu) and low (102 pfu) doses of influenza H1N1pdm09 virus. The low dose treated ferrets showed significant delays in innate immune response and virus shedding, delayed onset of pathological changes in the nasal cavity, and reduced pathological changes and viral RNA load in the lung, relative to untreated ferrets. Importantly, these observations were not seen in treated animals when the high dose challenge was used. In summary, low dose challenge gives a disease that more closely parallels the disease parameters of human influenza infection, and provides an improved pre-clinical model for the assessment of influenza therapeutics, and potentially, influenza vaccines.

Low dose influenza virus challenge in the ferret leads to increased virus shedding and greater sensitivity to oseltamivir.

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Anthony C Marriott

Full Text Available Ferrets are widely used to study human influenza virus infection. Their airway physiology and cell receptor distribution makes them ideal for the analysis of pathogenesis and virus transmission, and for testing the efficacy of anti-influenza interventions and vaccines. The 2009 pandemic influenza virus (H1N1pdm09 induces mild to moderate respiratory disease in infected ferrets, following inoculation with 106 plaque-forming units (pfu of virus. We have demonstrated that reducing the challenge dose to 102 pfu delays the onset of clinical signs by 1 day, and results in a modest reduction in clinical signs, and a less rapid nasal cavity innate immune response. There was also a delay in virus production in the upper respiratory tract, this was up to 9-fold greater and virus shedding was prolonged. Progression of infection to the lower respiratory tract was not noticeably delayed by the reduction in virus challenge. A dose of 104 pfu gave an infection that was intermediate between those of the 106 pfu and 102 pfu doses. To address the hypothesis that using a more authentic low challenge dose would facilitate a more sensitive model for antiviral efficacy, we used the well-known neuraminidase inhibitor, oseltamivir. Oseltamivir-treated and untreated ferrets were challenged with high (106 pfu and low (102 pfu doses of influenza H1N1pdm09 virus. The low dose treated ferrets showed significant delays in innate immune response and virus shedding, delayed onset of pathological changes in the nasal cavity, and reduced pathological changes and viral RNA load in the lung, relative to untreated ferrets. Importantly, these observations were not seen in treated animals when the high dose challenge was used. In summary, low dose challenge gives a disease that more closely parallels the disease parameters of human influenza infection, and provides an improved pre-clinical model for the assessment of influenza therapeutics, and potentially, influenza vaccines.

Detection of the antiviral drug oseltamivir in aquatic environments.

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Hanna Söderström

Full Text Available Oseltamivir (Tamiflu is the most important antiviral drug available and a cornerstone in the defence against a future influenza pandemic. Recent publications have shown that the active metabolite, oseltamivir carboxylate (OC, is not degraded in sewage treatment plants and is also persistent in aquatic environments. This implies that OC will be present in aquatic environments in areas where oseltamivir is prescribed to patients for therapeutic use. The country where oseltamivir is used most is Japan, where it is used to treat seasonal flu. We measured the levels of OC in water samples from the Yodo River system in the Kyoto and Osaka prefectures, Japan, taken before and during the flu-season 2007/8. No OC was detected before the flu-season but 2-58 ng L(-1 was detected in the samples taken during the flu season. This study shows, for the first time, that low levels of oseltamivir can be found in the aquatic environment. Therefore the natural reservoir of influenza virus, dabbling ducks, is exposed to oseltamivir, which could promote the evolution of viral resistance.

Use of oseltamivir in Dutch nursing homes during the 2004-2005 influenza season.

NARCIS (Netherlands)

Sande, Marianne A B van der; Ruijs, Wilhelmina L M; Meijer, Adam; Cools, Herman J M; Plas, Simone M van der

2006-01-01

To assess the implementation of guidelines for using neuraminidase inhibitors in the control of influenza outbreaks in Dutch nursing homes, data were collected on prophylactic and therapeutic use of anti-viral medication, indications for use and criteria for prescribing, based on experiences during

Large-scale FMO-MP3 calculations on the surface proteins of influenza virus, hemagglutinin (HA) and neuraminidase (NA)

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Mochizuki, Yuji; Yamashita, Katsumi; Fukuzawa, Kaori; Takematsu, Kazutomo; Watanabe, Hirofumi; Taguchi, Naoki; Okiyama, Yoshio; Tsuboi, Misako; Nakano, Tatsuya; Tanaka, Shigenori

2010-06-01

Two proteins on the influenza virus surface have been well known. One is hemagglutinin (HA) associated with the infection to cells. The fragment molecular orbital (FMO) calculations were performed on a complex consisting of HA trimer and two Fab-fragments at the third-order Møller-Plesset perturbation (MP3) level. The numbers of residues and 6-31G basis functions were 2351 and 201276, and thus a massively parallel-vector computer was utilized to accelerate the processing. This FMO-MP3 job was completed in 5.8 h with 1024 processors. Another protein is neuraminidase (NA) involved in the escape from infected cells. The FMO-MP3 calculation was also applied to analyze the interactions between oseltamivir and surrounding residues in pharmacophore.

Oseltamivir-resistant pandemic (H1N12009 in Yemen - case report

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Al-Kohlani Abdulhakeem

2010-05-01

Full Text Available Abstract Background During the influenza season of 2007-08, oseltamivir-resistant influenza A (H1N1 viruses emerged in several countries in Europe, North America, and Asia. Despite substantial prevalence of oseltamivir-resistant viruses, few data are available on the clinical profile of subjects infected with these viruses. Objectives: to describe the first oseltamivir-resistant (H1N1 influenza virus pandemic 2009 from the Eastern Mediterranean Region including Yemen and to determine the evidence by clinical presentation of children infected with these oseltamivir - resistant viruses. Methodology History, physical examination and laboratory investigations including Complete Blood Count, chest x-ray, blood cultures, CSF examination, LFTs, RFTs, blood for sugar, H1N1 test and oseltamivir resistance test. Results Nasal swabs indicated positivity on both H1N1 test and the RNP gene (Human R Nase P gene that serves as internal positive control for Human RNA. Both clinical specimens presented the mutation S31N in the M2 gene associated with resistance to adamantanes and H274Y in NA gene associated with resistance to oseltamivir. This was the first diagnosed case of resistance to oseltamivir in Yemen and also it is the first reported case of oseltamivir resistance virus in the Eastern Mediterranean Region. Conclusion The pattern of resistance found in the oseltamivir resistant isolate collected from Yemen is the same as has been reported elsewhere in other WHO regions. Clinical description and outcomes are not different from what is described elsewhere.

Oseltamivir-Resistant Flu

Centers for Disease Control (CDC) Podcasts

2012-04-13

Dr. Aaron Storms, an Epidemic Intelligence Service (EIS) officer at CDC, discusses his paper about oseltamivir-resistant H1N1flu.  Created: 4/13/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 4/17/2012.

OSELTAMIVIR APPLICATION AMONG HIV-INFECTED CHILDREN, SUFFERING FROM THE FLU

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Yu.A. Fomin

2007-01-01

Full Text Available The article provides the Oseltamivir application experience in flu treatment among HIV-infected children. The researchers showed that Oseltamivir is an effective medication for the given category of patients, reducing duration of the catarrhal syndrome and intoxication signs. The undesirable phenomena related to the medication intake proved to be transient and called for no cancellation of its use.Key words: children, hiv infection, flu, Oseltamivir.

Mixture toxicity of the antiviral drug Tamiflu (oseltamivir ethylester) and its active metabolite oseltamivir acid

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Escher, Beate I., E-mail: b.escher@uq.edu.au [University of Queensland, National Research Centre for Environmental Toxicology (Entox), 39 Kessels Rd, Brisbane, Qld 4108 (Australia); Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf (Switzerland); Bramaz, Nadine; Lienert, Judit; Neuwoehner, Judith [Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf (Switzerland); Straub, Juerg Oliver [F.Hoffmann-La Roche Ltd, Corporate Safety, Health and Environmental Protection, 4070 Basel (Switzerland)

2010-02-18

Tamiflu (oseltamivir ethylester) is an antiviral agent for the treatment of influenza A and B. The pro-drug Tamiflu is converted in the human body to the pharmacologically active metabolite, oseltamivir acid, with a yield of 75%. Oseltamivir acid is indirectly photodegradable and slowly biodegradable in sewage works and sediment/water systems. A previous environmental risk assessment has concluded that there is no bioaccumulation potential of either of the compounds. However, little was known about the ecotoxicity of the metabolite. Ester hydrolysis typically reduces the hydrophobicity and thus the toxicity of a compound. In this case, a zwitterionic, but overall neutral species is formed from the charged parent compound. If the speciation and predicted partitioning into biological membranes is considered, the metabolite may have a relevant contribution to the overall toxicity. These theoretical considerations triggered a study to investigate the toxicity of oseltamivir acid (OA), alone and in binary mixtures with its parent compound oseltamivir ethylester (OE). OE and OA were found to be baseline toxicants in the bioluminescence inhibition test with Vibrio fischeri. Their mixture effect lay between predictions for concentration addition and independent action for the mixture ratio excreted in urine and nine additional mixture ratios of OE and OA. In contrast, OE was an order of magnitude more toxic than OA towards algae, with a more pronounced effect when the direct inhibition of photosystem II was used as toxicity endpoint opposed to the 24 h growth rate endpoint. The binary mixtures in this assay yielded experimental mixture effects that agreed with predictions for independent action. This is consistent with the finding that OE exhibits slightly enhanced toxicity, while OA acts as baseline toxicant. Therefore, with respect to mixture classification, the two compounds can be considered as acting according to different modes of toxic action, although there are

Studies on Synthesis and Structure-Activity Relationship (SAR of Derivatives of a New Natural Product from Marine Fungi as Inhibitors of Influenza Virus Neuraminidase

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Yongcheng Lin

2011-10-01

Full Text Available Based on the natural isoprenyl phenyl ether from a mangrove-derived fungus, 32 analogues were synthesized and evaluated for inhibitory activity against influenza H1N1 neuraminidase. Compound 15 (3-(allyloxy-4-hydroxybenzaldehyde exhibited the most potent inhibitory activity, with IC50 values of 26.96 μM for A/GuangdongSB/01/2009 (H1N1, 27.73 μM for A/Guangdong/03/2009 (H1N1, and 25.13 μM for A/Guangdong/05/2009 (H1N1, respectively, which is stronger than the benzoic acid derivatives (~mM level. These are a new kind of non-nitrogenous aromatic ether Neuraminidase (NA inhibitors. Their structures are simple and the synthesis routes are not complex. The structure-activity relationship (SAR analysis revealed that the aryl aldehyde and unsubstituted hydroxyl were important to NA inhibitory activities. Molecular docking studies were carried out to explain the SAR of the compounds, and provided valuable information for further structure modification.

Homology modelling and docking studies on Neuraminidase enzyme as a natural product target for combating influenza

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Nisha Singh

2017-10-01

Full Text Available Influenza remains to be dreadful with yearly epidemics and sudden pandemic outbreaks causing significant mortality, even in nations with the most advanced health care systems. Thus, there has been a long-standing interest to develop effective and safe antiviral agents to treat infected individuals. Attempt to identify suitable molecular targets as antiviral compounds have focused recently on the influenza virus neuraminidase (NA, a key enzyme in viral replication [1]. In this research, virtual screening was done on a total of 600 natural compounds from 22 ethno medicinal Indian herbs for activity against neuraminidase enzyme exploiting representative protein conformations selected from molecular dynamics simulations. Neuraminidase enzyme sequences from different existing strains available on National Center of Biotechnology Information [2] (NCBI protein database were aligned using Clustal W [3] and CLC workbench 10 [4] to find the conserved residues. Neuraminidase protein sequence from H1N1 strain available on NCBI was used to structure 3D target model predicted against dataset from Protein data bank using modeller [5]. The target model was validated on different parameter at SAVES Server [6]. Using this target model a pharmacophore model was developed using ligand based strategy exploiting the three known inhibitors. The docking parameters were validated by redocking Zanamivir to its co-complex 2009 H1N1 NA crystal structure (PDB ID: 3TI5 generating best pose with a RMSD value of 0.7543 A°. This model was then used for in silico analysis of a library of natural compounds from 22 ethno medicinal Indian herbs known to have antiviral activity taken downloaded from PubChem database and selected on the basis of drug likeliness. All the compounds were docked in the binding pocket of neuraminidase. Top compounds having binding affinity better than or comparable to the control drug Zanamivir were selected and analyzed for their ADME and toxicity

Sales of oseltamivir in Norway prior to the emergence of oseltamivir resistant influenza A(H1N1 viruses in 2007–08

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Hungnes Olav

2009-05-01

Full Text Available Abstract Background An unprecedented high proportion of oseltamivir resistant influenza A(H1N1 viruses emerged in the 2007–08 influenza season. In Norway, two thirds of all tested A(H1N1 viruses were resistant to the antiviral drug. In order to see if this emergence could be explained by a drug induced selection pressure, we analysed data on the sales of oseltamivir in Norway for the years 2002–07. Methods We used data from two sources; the Norwegian Drug Wholesales Statistics Database and the Norwegian Prescription Database (NorPD, for the years 2002–2007. We calculated courses sold of oseltamivir (Tamiflu® per 1000 inhabitants per year. Results Our data showed that, except for the years 2005 and 2006, sales of oseltamivir were low in Norway; courses sold per 1000 inhabitants varied between 0.17–1.64. The higher sales in 2005 and 2006 we believe were caused by private stockpiling in fear of a pandemic, and do not represent actual usage. Conclusion A drug induced selection pressure was probably not the cause of the emergence of oseltamivir resistant influenza A(H1N1 viruses in 2007–08 in Norway.

Substrate-Competitive Activity-Based Profiling of Ester Prodrug Activating Enzymes.

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Xu, Hao; Majmudar, Jaimeen D; Davda, Dahvid; Ghanakota, Phani; Kim, Ki H; Carlson, Heather A; Showalter, Hollis D; Martin, Brent R; Amidon, Gordon L

2015-09-08

Understanding the mechanistic basis of prodrug delivery and activation is critical for establishing species-specific prodrug sensitivities necessary for evaluating preclinical animal models and potential drug-drug interactions. Despite significant adoption of prodrug methodologies for enhanced pharmacokinetics, functional annotation of prodrug activating enzymes is laborious and often unaddressed. Activity-based protein profiling (ABPP) describes an emerging chemoproteomic approach to assay active site occupancy within a mechanistically similar enzyme class in native proteomes. The serine hydrolase enzyme family is broadly reactive with reporter-linked fluorophosphonates, which have shown to provide a mechanism-based covalent labeling strategy to assay the activation state and active site occupancy of cellular serine amidases, esterases, and thioesterases. Here we describe a modified ABPP approach using direct substrate competition to identify activating enzymes for an ethyl ester prodrug, the influenza neuraminidase inhibitor oseltamivir. Substrate-competitive ABPP analysis identified carboxylesterase 1 (CES1) as an oseltamivir-activating enzyme in intestinal cell homogenates. Saturating concentrations of oseltamivir lead to a four-fold reduction in the observed rate constant for CES1 inactivation by fluorophosphonates. WWL50, a reported carbamate inhibitor of mouse CES1, blocked oseltamivir hydrolysis activity in human cell homogenates, confirming CES1 is the primary prodrug activating enzyme for oseltamivir in human liver and intestinal cell lines. The related carbamate inhibitor WWL79 inhibited mouse but not human CES1, providing a series of probes for analyzing prodrug activation mechanisms in different preclinical models. Overall, we present a substrate-competitive activity-based profiling approach for broadly surveying candidate prodrug hydrolyzing enzymes and outline the kinetic parameters for activating enzyme discovery, ester prodrug design, and

Chemical stability of oseltamivir in oral solutions.

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Albert, K; Bockshorn, J

2007-09-01

The stability of oseltamivir in oral aqueous solutions containing the preservative sodium benzoate was studied by a stability indicating HPLC-method. The separation was achieved on a RP-18 ec column using a gradient of mobile phase A (aqueous solution of 50 mM ammonium acetate) and mobile phase B (60% (v/v) acetonitrile/40% (v/v) mobile phase A). The assay was subsequently validated according to the ICH guideline Q2(R1). The extemporaneously prepared "Oseltamivir Oral Solution 15 mg/ml for Adults or for Children" (NRF 31.2.) according to the German National Formulary ("Neues Rezeptur-Formularium") was stable for 84 days if stored under refrigeration. After storage at 25 degrees C the content of oseltamivir decreased to 98.4%. Considering the toxicological limit of 0.5% of the 5-acetylamino derivative (the so-called isomer I) the solution is stable for 46 days. Oseltamivir was less stable in a solution prepared with potable water instead of purified water. Due to an increasing pH the stability of this solution decreased to 14 days. Furthermore a white precipitate of mainly calcium phosphate was observed. The addition of 0.1% anhydrous citric acid avoided these problems and improved the stability of the solution prepared with potable water to 63 days. Sodium benzoate was stable in all oral solutions tested.

Pharmacokinetics of oseltamivir in infants under the age of 1 year.

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Dixit, Rashmi; Matthews, Slade; Khandaker, Gulam; Walker, Karen; Festa, Marino; Booy, Robert

2016-12-01

Oseltamivir is the only antiviral treatment recommended for influenza in young children over the age of 1 year. There is scant data on oseltamivir pharmacokinetics (PK) in infants clearance in infants time points afterwards, to calculate Cmax (ng/mL), Tmax (h), AUC0-t (ng h/mL) and time for AUC (h). Four children with influenza A received oral oseltamivir, 2.35-3 mg/kg/dose. This dose range produced a target oseltamivir carboxylate plasma concentration in excess of the proposed 12-h target AUC of 3800 ng h/mL, selected from earlier studies to avert resistance. One patient developed GIT adverse event: dry retching. Oseltamivir was well tolerated at a dose of 2.35-3 mg/kg/dose twice a day in infants under the age of 1 year. In general agreement with earlier data, these doses produced a target oseltamivir carboxylate plasma exposure in excess of the proposed 12-h target exposure of AUC equal to 3800 ng h/mL in two patients. The limited plasma concentration data in the remaining two patients were not inconsistent with the target exposure being reached.

Carrier-Mediated Prodrug Uptake to Improve the Oral Bioavailability of Polar Drugs: An Application to an Oseltamivir Analogue.

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Incecayir, Tuba; Sun, Jing; Tsume, Yasuhiro; Xu, Hao; Gose, Tomoka; Nakanishi, Takeo; Tamai, Ikumi; Hilfinger, John; Lipka, Elke; Amidon, Gordon L

2016-02-01

The goal of this study was to improve the intestinal mucosal cell membrane permeability of the poorly absorbed guanidino analogue of a neuraminidase inhibitor, oseltamivir carboxylate (GOC) using a carrier-mediated strategy. Valyl amino acid prodrug of GOC with isopropyl-methylene-dioxy linker (GOC-ISP-Val) was evaluated as the potential substrate for intestinal oligopeptide transporter, hPEPT1 in Xenopus laevis oocytes heterologously expressing hPEPT1, and an intestinal mouse perfusion system. The diastereomers of GOC-ISP-Val were assessed for chemical and metabolic stability. Permeability of GOC-ISP-Val was determined in Caco-2 cells and mice. Diastereomer 2 was about 2 times more stable than diastereomer 1 in simulated intestinal fluid and rapidly hydrolyzed to the parent drug in cell homogenates. The prodrug had a 9 times-enhanced apparent permeability (P(app)) in Caco-2 cells compared with the parent drug. Both diastereomer exhibited high effective permeability (P(eff)) in mice, 6.32 ± 3.12 and 5.20 ± 2.81 × 10(-5) cm/s for diastereomer 1 and 2, respectively. GOC-ISP-Val was found to be a substrate of hPEPT1. Overall, this study indicates that the prodrug, GOC-ISP-Val, seems to be a promising oral anti-influenza agent that has sufficient stability at physiologically relevant pHs before absorption, significantly improved permeability via hPEPT1 and potentially rapid activation in the intestinal cells. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Mouse Saliva Inhibits Transit of Influenza Virus to the Lower Respiratory Tract by Efficiently Blocking Influenza Virus Neuraminidase Activity.

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Gilbertson, Brad; Ng, Wy Ching; Crawford, Simon; McKimm-Breschkin, Jenny L; Brown, Lorena E

2017-07-15

We previously identified a novel inhibitor of influenza virus in mouse saliva that halts the progression of susceptible viruses from the upper to the lower respiratory tract of mice in vivo and neutralizes viral infectivity in MDCK cells. Here, we investigated the viral target of the salivary inhibitor by using reverse genetics to create hybrid viruses with some surface proteins derived from an inhibitor-sensitive strain and others from an inhibitor-resistant strain. These viruses demonstrated that the origin of the viral neuraminidase (NA), but not the hemagglutinin or matrix protein, was the determinant of susceptibility to the inhibitor. Comparison of the NA sequences of a panel of H3N2 viruses with differing sensitivities to the salivary inhibitor revealed that surface residues 368 to 370 (N2 numbering) outside the active site played a key role in resistance. Resistant viruses contained an EDS motif at this location, and mutation to either EES or KDS, found in highly susceptible strains, significantly increased in vitro susceptibility to the inhibitor and reduced the ability of the virus to progress to the lungs when the viral inoculum was initially confined to the upper respiratory tract. In the presence of saliva, viral strains with a susceptible NA could not be efficiently released from the surfaces of infected MDCK cells and had reduced enzymatic activity based on their ability to cleave substrate in vitro This work indicates that the mouse has evolved an innate inhibitor similar in function, though not in mechanism, to what humans have created synthetically as an antiviral drug for influenza virus. IMPORTANCE Despite widespread use of experimental pulmonary infection of the laboratory mouse to study influenza virus infection and pathogenesis, to our knowledge, mice do not naturally succumb to influenza. Here, we show that mice produce their own natural form of neuraminidase inhibitor in saliva that stops the virus from reaching the lungs, providing a

The influence of 150-cavity binders on the dynamics of influenza A neuraminidases as revealed by molecular dynamics simulations and combined clustering.

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Kyle T Greenway

Full Text Available Neuraminidase inhibitors are the main pharmaceutical agents employed for treatments of influenza infections. The neuraminidase structures typically exhibit a 150-cavity, an exposed pocket that is adjacent to the catalytic site. This site offers promising additional contact points for improving potency of existing pharmaceuticals, as well as generating entirely new candidate inhibitors. Several inhibitors based on known compounds and designed to interact with 150-cavity residues have been reported. However, the dynamics of any of these inhibitors remains unstudied and their viability remains unknown. This work reports the outcome of long-term, all-atom molecular dynamics simulations of four such inhibitors, along with three standard inhibitors for comparison. Each is studied in complex with four representative neuraminidase structures, which are also simulated in the absence of ligands for comparison, resulting in a total simulation time of 9.6 µs. Our results demonstrate that standard inhibitors characteristically reduce the mobility of these dynamic proteins, while the 150-binders do not, instead giving rise to many unique conformations. We further describe an improved RMSD-based clustering technique that isolates these conformations--the structures of which are provided to facilitate future molecular docking studies--and reveals their interdependence. We find that this approach confers many advantages over previously described techniques, and the implications for rational drug design are discussed.

Potential adverse effects of oseltamivir in rats: males are more vulnerable than females.

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El-Sayed, Wael M; Al-Kahtani, Mohamed Ali

2011-09-01

Oseltamivir is the most widely used antiviral drug for the treatment and prophylaxis of influenza. However, not much is known about its adverse effects. The potential side effects were investigated in male and female rats (140-170 g). Oseltamivir was administered at 2.2 mg·kg(-1)·day(-1) for 5 days. For both genders, treatment with oseltamivir resulted in significant reductions in the hepatic activities of glutathione reductase, glutathione peroxidase, and glutathione S-transferase. Also for both genders, oseltamivir produced modest reductions in the hepatic activities of UDP-glucuronosyltransferase, quinone oxidoreductase, thioredoxin reductase, CYP1A1/2, and CYP3A, as well as hepatic glutathione content. For both genders, neither the kidney functions nor protein profile was affected by oseltamivir. Oseltamivir also caused significant elevation in serum levels of both triacylglycerols and LDL-cholesterol and in the activity of γ-glutamyl transpeptidase, in both genders. For male animals only, oseltamivir treatment elevated the serum level of total cholesterol as well as the activity of serum alanine aminotransferase, and reduced the hepatic activities of superoxide dismutase and catalase. Oseltamivir caused oxidative stress and acute toxicity in the liver, and disrupted the cholesterol and lipid metabolism but was less likely to cause serious drug interactions. There was a sexual differentiation in these adverse effects, with adverse effects being more evident in male rats.

Computational design of drug candidates for influenza A virus subtype H1N1 by inhibiting the viral neuraminidase-1 enzyme

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Tambunan Usman Sumo Friend

2014-06-01

Full Text Available It is critical to seek potential alternative treatments for H1N1 infections by inhibiting neuraminidase-1 enzyme. One of the viable options for inhibiting the activity of neuraminidase- 1 is peptide drug design. In order to increase peptide stability, cyclization is necessary to prevent its digestion by protease enzyme. Cyclization of peptide ligands by formation of disulfide bridges is preferable for designing inhibitors of neuraminidase-1 because of their high activity and specificity. Here we designed ligands by using molecular docking, drug scan and dynamics computational methods. Based on our docking results, short polypeptides of cystein-arginine-methionine-tyrosine- -proline-cysteine (CRMYPC and cysteine-arginine-aspargine- phenylalanine-proline-cysteine (CRNFPC have good residual interactions with the target and the binding energy ΔGbinding of -31.7402 and -31.0144 kcal mol-1, respectively. These values are much lower than those of the standards, and it means that both ligands are more accessible to ligand-receptor binding. Based on drug scan results, both of these ligands are neither mutagenic nor carcinogenic. They also show good oral bioavailability. Moreover, both ligands show relatively stable molecular dynamics progression of RMSD vs. time plot. However, based on our metods, the CRMYPC ligand has sufficient hydrogen bonding interactions with residues of the active side of neuraminidase-1 and can be therefore proposed as a potential inhibitor of neuraminidase-1

Virtual screening approach to identifying influenza virus neuraminidase inhibitors using molecular docking combined with machine-learning-based scoring function.

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Zhang, Li; Ai, Hai-Xin; Li, Shi-Meng; Qi, Meng-Yuan; Zhao, Jian; Zhao, Qi; Liu, Hong-Sheng

2017-10-10

In recent years, an epidemic of the highly pathogenic avian influenza H7N9 virus has persisted in China, with a high mortality rate. To develop novel anti-influenza therapies, we have constructed a machine-learning-based scoring function (RF-NA-Score) for the effective virtual screening of lead compounds targeting the viral neuraminidase (NA) protein. RF-NA-Score is more accurate than RF-Score, with a root-mean-square error of 1.46, Pearson's correlation coefficient of 0.707, and Spearman's rank correlation coefficient of 0.707 in a 5-fold cross-validation study. The performance of RF-NA-Score in a docking-based virtual screening of NA inhibitors was evaluated with a dataset containing 281 NA inhibitors and 322 noninhibitors. Compared with other docking-rescoring virtual screening strategies, rescoring with RF-NA-Score significantly improved the efficiency of virtual screening, and a strategy that averaged the scores given by RF-NA-Score, based on the binding conformations predicted with AutoDock, AutoDock Vina, and LeDock, was shown to be the best strategy. This strategy was then applied to the virtual screening of NA inhibitors in the SPECS database. The 100 selected compounds were tested in an in vitro H7N9 NA inhibition assay, and two compounds with novel scaffolds showed moderate inhibitory activities. These results indicate that RF-NA-Score improves the efficiency of virtual screening for NA inhibitors, and can be used successfully to identify new NA inhibitor scaffolds. Scoring functions specific for other drug targets could also be established with the same method.

Pandemic pharmaceutical dosing effects on wastewater treatment: no adaptation of activated sludge bacteria to degrade the antiviral drug oseltamivir (Tamiflu®) and loss of nutrient removal performance.

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Slater, Frances R; Singer, Andrew C; Turner, Susan; Barr, Jeremy J; Bond, Philip L

2011-02-01

The 2009-2010 influenza pandemic saw many people treated with antivirals and antibiotics. High proportions of both classes of drugs are excreted and enter wastewater treatment plants (WWTPs) in biologically active forms. To date, there has been no study into the potential for influenza pandemic-scale pharmaceutical use to disrupt WWTP function. Furthermore, there is currently little indication as to whether WWTP microbial consortia can degrade antiviral neuraminidase inhibitors when exposed to pandemic-scale doses. In this study, we exposed an aerobic granular sludge sequencing batch reactor, operated for enhanced biological phosphorus removal (EBPR), to a simulated influenza-pandemic dosing of antibiotics and antivirals for 8 weeks. We monitored the removal of the active form of Tamiflu(®), oseltamivir carboxylate (OC), bacterial community structure, granule structure and changes in EBPR and nitrification performance. There was little removal of OC by sludge and no evidence that the activated sludge community adapted to degrade OC. There was evidence of changes to the bacterial community structure and disruption to EBPR and nitrification during and after high-OC dosing. This work highlights the potential for the antiviral contamination of receiving waters and indicates the risk of destabilizing WWTP microbial consortia as a result of high concentrations of bioactive pharmaceuticals during an influenza pandemic. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Identification of single amino acid substitutions (SAAS) in neuraminidase from influenza a virus (H1N1) via mass spectrometry analysis coupled with de novo peptide sequencing.

Science.gov (United States)

Peng, Qisheng; Wang, Zijian; Wu, Donglin; Li, Xiaoou; Liu, Xiaofeng; Sun, Wanchun; Liu, Ning

2016-08-01

Amino acid substitutions in the neuraminidase of the influenza virus are the main cause of the emergence of resistance to zanamivir or oseltamivir during seasonal influenza treatment; they are the result of non-synonymous mutations in the viral genome that can be successfully detected by polymer chain reaction (PCR)-based approaches. There is always an urgent need to detect variation in amino acid sequences directly at the protein level. Mass spectrometry coupled with de novo sequencing has been explored as an alternative and straightforward strategy for detecting amino acid substitutions, as well - this approach is the primary focus of the present study. Influenza virus (A/Puerto Rico/8/1934 H1N1) propagated in embryonated chicken eggs was purified by ultracentrifugation, followed by PNGase F treatment. The deglycosylated virion was lysed and separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The gel band corresponding to neuraminidase was picked up and subjected to liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. LC-MS/MS analyses, coupled with manual de novo sequencing, allowed the determination of three amino acid substitutions: R346K, S349 N, and S370I/L, in the neuraminidase from the influenza virus (A/Puerto Rico/8/1934 H1N1), which were located in three mutated peptides of the neuraminidase: YGNGVWIGK, TKNHSSR, and PNGWTETDI/LK, respectively. We found that the amino acid substitutions in the proteins of RNA viruses (including influenza A virus) resulting from non-synonymous gene mutations can indeed be directly analyzed via mass spectrometry, and that manual interpretation of the MS/MS data may be beneficial. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

In silico molecular modeling of neuraminidase enzyme H1N1 avian influenza virus and docking with zanamivir ligands

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Muthiyan Ramachandran

2012-12-01

Full Text Available Objective: Neuraminidase is an enzyme aspartic protease that is essential for the life cycle of H1N1. Methods: Constructed a model of Neuraminidase enzyme the 3D structure as template using with Modeller software. The Neuraminidase enzyme model was predicted and validated by Procheck, What check, Errat, Verify-3D and AutoDock web server for reliability. Results: The Modeller homology-modeling algorithm was demonstrated excellent accuracy in blind predictions. The Neuraminidase enzyme model built with little, 35% identity could be accurate enough to be successfully used in receptor based rational drug design. The closest homologue with the highest sequence identity 100% was selected. Zanamivir drug and analogues were retrieved from PubChem database, as well as subjected to docking interaction with Neuraminidase enzyme used AutoDock programme. Based on the root mean square deviation and lowest binding energy values the best docking orientation was selected. The better lowest binding energy value -6.91 was selected of CID_25209232. Conclusions: This study will be used in broad screening of inhibitors of the protein. However, further implemented experimental and clinical verification is needed to establishment these analogues as drug.

Discover binding pathways using the sliding binding-box docking approach: application to binding pathways of oseltamivir to avian influenza H5N1 neuraminidase

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Tran, Diem-Trang T.; Le, Ly T.; Truong, Thanh N.

2013-08-01

Drug binding and unbinding are transient processes which are hardly observed by experiment and difficult to analyze by computational techniques. In this paper, we employed a cost-effective method called "pathway docking" in which molecular docking was used to screen ligand-receptor binding free energy surface to reveal possible paths of ligand approaching protein binding pocket. A case study was applied on oseltamivir, the key drug against influenza a virus. The equilibrium pathways identified by this method are found to be similar to those identified in prior studies using highly expensive computational approaches.

Oseltamivir (Tamiflu® in the environment, resistance development in influenza A viruses of dabbling ducks and the risk of transmission of an oseltamivir-resistant virus to humans – a review

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Josef D. Järhult

2012-06-01

Full Text Available The antiviral drug oseltamivir (Tamiflu® is a cornerstone in influenza pandemic preparedness plans worldwide. However, resistance to the drug is a growing concern. The active metabolite oseltamivir carboxylate (OC is not degraded in surface water or sewage treatment plants and has been detected in river water during seasonal influenza outbreaks. The natural influenza reservoir, dabbling ducks, can thus be exposed to OC in aquatic environments. Environmental-like levels of OC induce resistance development in influenza A/H1N1 virus in mallards. There is a risk of resistance accumulation in influenza viruses circulating among wild birds when oseltamivir is used extensively. By reassortment or direct transmission, oseltamivir resistance can be transmitted to humans potentially causing a resistant pandemic or human-adapted highly-pathogenic avian influenza virus. There is a need for more research on resistance development in the natural influenza reservoir and for a prudent use of antivirals.

The anti-influenza drug oseltamivir evokes hypothermia in mice through dopamine D2 receptor activation via central actions

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Akihiro Fukushima

2018-01-01

Full Text Available Oseltamivir has a hypothermic effect in mice when injected intraperitoneally (i.p. and intracerebroventricularly (i.c.v.. Here we show that the hypothermia evoked by i.c.v.-oseltamivir is inhibited by non-selective dopamine receptor antagonists (sulpiride and haloperidol and the D2-selective antagonist L-741,626, but not by D1/D5-selective and D3-selective antagonists (SCH-23390 and SB-277011-A, respectively. The hypothermic effect of i.p.-administered oseltamivir was not inhibited by sulpiride, haloperidol, L-741,626 and SCH-23390. In addition, neither sulpiride, haloperidol nor SCH-23390 blocked hypothermia evoked by i.c.v.-administered oseltamivir carboxylate (a hydrolyzed metabolite of oseltamivir. These results suggest that oseltamivir in the brain induces hypothermia through activation of dopamine D2 receptors.

Oseltamivir compounding in the hospital pharmacy during the (H1N1 influenza pandemic

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Márcia Lúcia de Mário Marin

2010-01-01

Full Text Available AIMS: Pandemics impose large demands on the health care system. The supply of appropriate chemotherapeutic agents, namely oseltamivir solution, presented a serious challenge in the recent influenza pandemic. This study reports on the rational series of pharmacotechnical steps that were followed to appropriately handle bulk oseltamivir powder to meet the increased demand. METHODS: During a six-week period in August and September of 2009, a task force was created in the Central Pharmacy of Hospital das Clínicas to convert imported oseltamivir phosphate into ready-to-use solution for utilization by physicians and public health authorities. The protocol included dissolution, physico-chemical tests and the bottling of a liquid microdose formulation for emergency room and outpatient dispensing with adequate quality control during all phases. RESULTS: The successful production routine was based on a specially designed flowchart according to which a batch of 33210 g of oseltamivir powder was converted into 32175 solution units during the aforementioned period with a net loss of only 2.6%. The end products were bottles containing 50 ml of 15 mg/mL oseltamivir solution. The measured concentration was stable and accurate (97.5% - 102.0% of the nominal value. The drug was prescribed as both a prophylactic and therapeutic agent. DISCUSSION: Hospital pharmacies are conventionally engaged in the manipulation of medical prescriptions and specialty drugs. They are generally responsible for only small-scale equipment used for manufacturing and quality-control procedures. The compounding of oseltamivir was a unique effort dictated by exceptional circumstances. CONCLUSION: The shortage of oseltamivir solution for clinical use was solved by emergency operationalization of a semi-industrial process in which bulk powder was converted into practical vials for prompt delivery.

Radioassay method of neuraminidase towards N-acetylneuraminosyl hexasaccharides

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Kuriyama, M; Someya, F; Yamada, T; Miyatake, T [Tokyo Metropolitan Research Lab. of Public Health (Japan)

1982-02-26

The authors have devised a sensitive method to assay for neuraminidase activities towards ..cap alpha..-(2..-->..3)-N-acetylneuraminosyl hexasaccharide and ..cap alpha..-(2..-->..6)-N-acetylneuraminosyl hexasaccharide, which were isolated from the urine of a patient with adult sialidosis with partial deficiency of ..beta..-galactosidase. Standard assay conditions for the determination of these neuraminidase activities were established and the radiolabeled reduced derivatives of these substrates were used. The fibroblast neuraminidase had its maximum activity at pH 4.0-4.2, with Ksub(m) values of 2.22 x 10/sup -3/ and 4.17 x 10/sup -3/ mol/l and Vsub(max) values of 76.9 and 28.6 nmol.mg/sup -1/ protein.h/sup -1/ towards the 2..-->..3 isomer and the 2..-->..6 isomer, respectively. Neuraminidase deficiencies were found in the fibroblasts of adult sialidosis, mucolipidosis II and III. These studies were compared with the neuraminidase activity towards ..cap alpha..-(2..-->..3)-N-acetylneuraminosyl lactose.

Purification of neuraminidase from Influenza virus subtype H5N1

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Simson Tariga

2009-03-01

Full Text Available Influenza-virus neuraminidase plays vital role in the survival of the organisms. Vaccination of animals with this glycoprotein confers immune responses so that enable it to protect the animals from incoming infection. Supplementation of conventional vaccines with this glycoprotein increases the protection and longevity of the vaccine. Purified neuraminidase can also be used to develop serological tests for differentiation of serologically positive animals due to infection or to vaccination. In this study purification of neuraminidase from influenza virus subtype H5N1 was described. Triton x-100 and Octyl β-D-glucopyranoside were used to extract and diluted the glycoprotein membrane. The enzymatic activity of the neuraminidase was assayed using a fluorochrome substrate, 4-methylumbelliferyl-a-D-N-acetyl neuraminic acid, which was found to be simple, sensitive and suitable for the purification purpose. The neuraminidase was absorbed selectively on an oxamic-acid agarose column. The purity of neuraminidase eluted from this affinity column was high. A higher purity of the neuraminidase was obtained by further separation with gel filtration on Superdex-200. The purified neuraminidase was enzymatically active and did not contain any detectable haemagglutinin, either by haemagglutination assay or by monospecific antibodies raised against H5N1 hemagglutinin. The purified neuraminidase was recognized strongly by antibodies raised against an internal but only weakly by that against C-terminal regions of the neuraminidase protein of H5N1-influenza virus. The purified neuraminidase was in tetrameric forms but dissociated into monomeric form on reducing condition, or mostly dimeric form on non-reducing SDS-PAGE.

Determining the Quality of Oseltamivir (Tamiflu)

Centers for Disease Control (CDC) Podcasts

The possibility of an avian flu pandemic has given Tamiflu attention. Because of fear of a pandemic, this drug has been in high demand. Unfortunately, this demand has prompted production of counterfeit Tamiflu. CDC's Dr. Mike Green discusses a test that is simple and affordable and can test the quality of products purported to be oseltamivir (Tamiflu).

The stimulatory effects of caffeine with oseltamivir (Tamiflu) on light-dark behavior and open-field behavior in mice.

Science.gov (United States)

Uchiyama, Hidemori; Toda, Akihisa; Imoto, Masumi; Nishimura, Satoko; Kuroki, Hiroaki; Soeda, Shinji; Shimeno, Hiroshi; Watanabe, Shigenori; Eyanagi, Reiko

2010-01-22

Abnormal behaviors and death associated with the use of oseltamivir (Tamiflu) have emerged as a major issue in influenza patients taking the drug. Here, we investigated the mechanisms underlying the effects of oseltamivir on the behavior of mice using light-dark and open-field preference tests. Oseltamivir (75 and 150 mg/kg, intraperitoneally (i.p.)) alone affected neither time spent in the open area in the light-dark preference test nor ambulation in the open-field test at 2h post-injection. However, a non-selective adenosine A(1)/A(2) receptor antagonist, caffeine (10mg/kg, i.p.) in combination with oseltamivir (150 mg/kg, i.p.) increased time spent in the open area in the light-dark preference test. This enhancement was not inhibited by a benzodiazepine receptor antagonist, flumazenil (10-20mg/kg, subcutaneously (s.c.)). Enhancement of ambulation in the open-field test was also observed when caffeine (10mg/kg, i.p.) was combined with oseltamivir (150 mg/kg, i.p.). This enhancement was inhibited by a dopamine D(2) receptor antagonist, haloperidol (0.1mg/kg, s.c.). Furthermore, an adenosine A(2) receptor antagonist, SCH58261 (3mg/kg, i.p.) in combination with oseltamivir (150 mg/kg, i.p.) increased ambulation in the open-field test, while an adenosine A(1) receptor antagonist, DPCPX (1-3mg/kg, i.p.) did not. These findings suggest that the actions of oseltamivir may involve the dopamine and adenosine systems. Our findings suggest that due to the interaction between central blockade of adenosine A(2) receptors by caffeine, and oseltamivir-induced behavioral changes, patients being treated with oseltamivir should be closely monitored. (c) 2009 Elsevier Ireland Ltd. All rights reserved.

Assessing the in vitro fitness of an oseltamivir-resistant seasonal A/H1N1 influenza strain using a mathematical model.

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Benjamin P Holder

2011-03-01

Full Text Available In 2007, the A/Brisbane/59/2007 (H1N1 seasonal influenza virus strain acquired the oseltamivir-resistance mutation H275Y in its neuraminidase (NA gene. Although previous studies had demonstrated that this mutation impaired the replication capacity of the influenza virus in vitro and in vivo, the A/Brisbane/59/2007 H275Y oseltamivir-resistant mutant completely out-competed the wild-type (WT strain and was, in the 2008-2009 influenza season, the primary A/H1N1 circulating strain. Using a combination of plaque and viral yield assays, and a simple mathematical model, approximate values were extracted for two basic viral kinetics parameters of the in vitro infection. In the ST6GalI-MDCK cell line, the latent infection period (i.e., the time for a newly infected cell to start releasing virions was found to be 1-3 h for the WT strain and more than 7 h for the H275Y mutant. The infecting time (i.e., the time for a single infectious cell to cause the infection of another one was between 30 and 80 min for the WT, and less than 5 min for the H275Y mutant. Single-cycle viral yield experiments have provided qualitative confirmation of these findings. These results, though preliminary, suggest that the increased fitness success of the A/Brisbane/59/2007 H275Y mutant may be due to increased infectivity compensating for an impaired or delayed viral release, and are consistent with recent evidence for the mechanistic origins of fitness reduction and recovery in NA expression. The method applied here can reconcile seemingly contradictory results from the plaque and yield assays as two complementary views of replication kinetics, with both required to fully capture a strain's fitness.

Studies on sequestration of neuraminidase-treated red blood cells

International Nuclear Information System (INIS)

Simchon, S.; Jan, K.M.; Chien, S.

1988-01-01

The effects of reduction in the surface charge of red blood cells (RBCs) on regional blood flow and RBC distribution were studied in rats anesthetized with pentobarbital sodium. RBCs were treated with neuraminidase to reduce their electrophoretic mobility by 56%. Normal and neuraminidase-treated RBCs labeled with 51Cr or 111In were injected into a femoral vein while an equal volume of blood was simultaneously withdrawn from a femoral artery. More than 70% of the neuraminidase-treated RBCs injected disappeared from the circulating blood in 30 min compared with less than 2% of normal RBCs. The relative distributions of neuraminidase-treated RBCs to normal RBCs, as determined from radioactivity counting, were significantly greater than 1 in the spleen (5.65 +/- 0.97, mean +/- SD), the liver (2.84 +/- 0.21), the lung (1.48 +/- 0.31), and the kidney (1.49 +/- 0.27), indicating a preferential trapping of neuraminidase-treated RBCs in these regions. This ratio was approximately 1 in all other organs. Regional blood flows in tissues were determined with 15-micron microspheres in the control period and after the infusion of neuraminidase-treated RBCs (experimental). Experimental-to-control blood flow ratios were 0.40 +/- 0.05 in the spleen, 0.66 +/- 0.06 in the liver, 0.78 +/- 0.03 in the lung, and 0.78 +/- 0.09 in the kidneys; this ratio was approximately 1 in all other organs. An experimental-to-control blood flow ratio less than 1 indicates a reduction in blood flow; this occurred in the same organs as those with trapping of neuraminidase-treated RBCs

A practical and azide-free synthetic approach to oseltamivir from diethyl D-tartrate.

Science.gov (United States)

Weng, Jiang; Li, Yong-Bo; Wang, Rui-Bin; Li, Feng-Quan; Liu, Can; Chan, Albert S C; Lu, Gui

2010-05-07

A short and practical synthesis of oseltamivir was accomplished in 11 steps from inexpensive and abundant diethyl D-tartrate starting material. This azide-free route featured an asymmetric aza-Henry reaction and a domino nitro-Michael/Horner-Wadsworth-Emmons (HWE) reaction as the key steps to construct the relevant cyclohexene ring of the product, which provided an economical and practical alternative for the synthesis of oseltamivir.

Surveillance van het verloop van influenza-uitbraken en oseltamivir gebruik in verpleeg- en verzorgingshuizen in Nederland

NARCIS (Netherlands)

van Gageldonk-Lafeber AB; van der Sande MAB; van Vliet JA; Koopmans MPG; Ruijs WLM; Meijer A; Wilbrink B; van der Plas SM; CIE; LIS

2006-01-01

Er is nog niet met zekerheid vastgesteld of het middel oseltamivir griepuitbraken in verpleeg- en verzorgingshuizen verkort. De lage vaccinatiegraad onder het personeel en verlate inzet van oseltamivir veroorzaken deze onzekerheid. Dit blijkt uit een surveillance in negen zorginstellingen in het

Review of potential drug interaction between Oseltamivir and Warfarin and why it is important for emergency medicine physicians.

Science.gov (United States)

Shah, Siddharth P; Patel, Kinner M; Subedi, Rogin; Gambhir, Harvir Singh

2017-08-01

Oseltamivir is a very commonly prescribed anti-viral medication by the Emergency Medicine (EM) physicians for the prophylactic and therapeutic treatment of Influenza infection. While the drug interaction of Warfarin with various antibiotics is known, the drug interaction between Oseltamivir and Warfarin is not common. We present a case where an 83-year female patient, on Warfarin for Pulmonary Embolism, had worsening of coagulopathy after she was started on Oseltamivir. The INR was monitored daily in our patient and Warfarin was stopped when the INR became supra-therapeutic. Our patient did not have any minor or major bleeding complication. This is the first reported case of Oseltamivir related worsening coagulopathy in patient on Warfarin to the best of our knowledge. Keeping in mind the possible interaction between the two as it was evident in our case and few other published reports, we recommend monitoring the INR closely in patients using Warfarin after they are started on Oseltamivir therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

Neuraminidase inhibitor resistance in influenza: assessing the danger of its generation and spread.

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Andreas Handel

2007-12-01

Full Text Available Neuraminidase Inhibitors (NI are currently the most effective drugs against influenza. Recent cases of NI resistance are a cause for concern. To assess the danger of NI resistance, a number of studies have reported the fraction of treated patients from which resistant strains could be isolated. Unfortunately, those results strongly depend on the details of the experimental protocol. Additionally, knowing the fraction of patients harboring resistance is not too useful by itself. Instead, we want to know how likely it is that an infected patient can generate a resistant infection in a secondary host, and how likely it is that the resistant strain subsequently spreads. While estimates for these parameters can often be obtained from epidemiological data, such data is lacking for NI resistance in influenza. Here, we use an approach that does not rely on epidemiological data. Instead, we combine data from influenza infections of human volunteers with a mathematical framework that allows estimation of the parameters that govern the initial generation and subsequent spread of resistance. We show how these parameters are influenced by changes in drug efficacy, timing of treatment, fitness of the resistant strain, and details of virus and immune system dynamics. Our study provides estimates for parameters that can be directly used in mathematical and computational models to study how NI usage might lead to the emergence and spread of resistance in the population. We find that the initial generation of resistant cases is most likely lower than the fraction of resistant cases reported. However, we also show that the results depend strongly on the details of the within-host dynamics of influenza infections, and most importantly, the role the immune system plays. Better knowledge of the quantitative dynamics of the immune response during influenza infections will be crucial to further improve the results.

Oseltamivir and Neuropsychiatric Behaviors – A Case Report on an Adolescent Teen and Evaluation of the Literature

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Tsz-Yin SO

2009-11-01

Full Text Available OBJECTIVE: To illustrate a case of oseltamivir induced neuropsychiatric behaviors in an adolescent teen. CASE SUMMARY: A 15-year-old previously healthy adolescent presented to the emergency department with acute onset of altered mental status after taking two doses of oseltamivir prescribed to him by his primary care physician for presumed influenza infection. A thorough examination at the hospital, which included a urine drug screen, complete blood count, complete metabolic panel, urine and blood cultures, head computed tomography, and chest radiograph, did not indicate any other clinical conditions that could explain his abnormal behaviors. No other medications were given to him in the hospital. About 20 hours after the last dose of oseltamivir, he awoke from a nap and his mental status was completely back to baseline. He had no memory of the events transpired in the past 24 hours and was discharged home with no further incidence.DISSCUSION: Oseltamivir is an anti-viral agent that is often used as treatment and prophylaxis for influenza infection. Neuropsychiatric adverse events such as hallucination and delirium can potentially occur with this agent. This rare adverse event may be due to the binding of the medication to the enzyme sialidase causing increase in dopamine activity. Most of the reports were in young Japanese children less than 16 years old. Some studies have shown a causal relationship with oseltamivir leading to this adverse event, while some have failed to do so, probably due to flaws in their analytical method. The Naranjo ADR probability scale showed a possible causality between neuropsychiatric behaviors and oseltamivir administration in this patient.CONCLUSIONS: Oseltamivir is an effective anti-viral for influenza infection if started early in the course of the illness. Clinicians should monitor for neuropsychiatric symptoms when starting patients on this medication.

Importance of Accurate Charges in Binding Affinity Calculations: A Case of Neuraminidase Series

Energy Technology Data Exchange (ETDEWEB)

Park, Kichul; Kyun, Nack Sung; Cho, Art E. [Korea Univ., Sejong (Korea, Republic of)

2013-02-15

It has been shown that calculating atomic charges using quantum mechanical level theory greatly improves the accuracy of docking. A protocol was developed and shown to be effective. That this protocol works is just a manifestation of the fact that electrostatic interactions are important in protein-ligand binding. In order to investigate how the same protocol helps in prediction of binding affinities, we took a series of known cocrystal structures of influenza neuraminidase inhibitors with the receptor and performed docking with Glide SP, Glide XP, and QPLD, the last being a workflow that incorporates QM/MM calculations to replace the fixed atomic charges of force fields with quantum mechanically recalculated ones at a given docking pose, and predicted the binding affinities of each cocrystal. The correlation with experimental binding affinities considerably improved with QPLD compared to Glide SP/XP yielding r{sup 2} = 0.83. The results suggest that for binding sites, such as that of neuraminidase, which are laden with hydrophilic residues, protocols such as QPLD which utilizes QM-based atomic charges can better predict the binding affinities.

Determining the Quality of Oseltamivir (Tamiflu)

Centers for Disease Control (CDC) Podcasts

2008-02-04

The possibility of an avian flu pandemic has given Tamiflu attention. Because of fear of a pandemic, this drug has been in high demand. Unfortunately, this demand has prompted production of counterfeit Tamiflu. CDC's Dr. Mike Green discusses a test that is simple and affordable and can test the quality of products purported to be oseltamivir (Tamiflu).  Created: 2/4/2008 by Emerging Infectious Diseases.   Date Released: 2/20/2008.

Oseltamivir (Tamiflu-induced bilateral acute angle closure glaucoma and transient myopia

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Ji Woong Lee

2014-01-01

Full Text Available A 27-year-old woman developed bilateral acute angle closure glaucoma (AACG and transient myopia after taking oseltamivir for four days. On the fourth day, she received systemic and topical intraocular pressure (IOP-lowering agents, and IOP decreased in both eyes. However, her visual acuity was unchanged. A myopic shift of -5.25 D OD and -5.0 D OS was estimated to have occurred in the acute phase. A-scan ultrasonography and Pentacam showed markedly shallow anterior chambers and increased lens thickness. Ultrasound biomicroscopy revealed an annular ciliochoroidal effusion with forward displacement of the lens-iris diaphragm. Ciliochoroidal effusion and transient myopia were resolved after discontinuation of oseltamivir.

Targeted antiviral prophylaxis with oseltamivir in a summer camp setting.

Science.gov (United States)

Kimberlin, David W; Escude, Janell; Gantner, Janel; Ott, Jeanne; Dronet, Melissa; Stewart, Timothy A; Jester, Penelope; Redden, David T; Chapman, Whitney; Hammond, Rob

2010-04-01

To describe the effectiveness of containment of novel influenza A(H1N1) infection at a summer camp. Targeted use of oseltamivir phosphate by individuals in close contact with influenza-confirmed cases. Boys' camp in Alabama in July 2009. A total of 171 campers, 48 camp counselors, and 27 camp staff. Campers with confirmed influenza received oseltamivir and were immediately isolated and sent home. All boys and counselors in the infected child's adjoining cabins received prophylactic oseltamivir for 10 days, including 8 campers at higher risk for influenza infection (eg, those with asthma, seizure disorder, or diabetes). Alcohol-based hand sanitizer was provided at each of the daily activities, in the boys' cabins, and in the dining hall, and counselors were educated by the medical staff on the spread of influenza and its prevention through good hand hygiene. All cabins, bathrooms, and community sports equipment were sprayed or wiped down with disinfectant each day. Main Outcome Measure Virologic confirmation of influenza. Three of the 171 campers tested positive for influenza A during the course of the 2-week fourth session, for an attack rate of 1.8%. The probability of observing 3 or fewer infected campers if the attack rate was 12% is less than 1 in 10,000,000 (P hand sanitization and surface decontamination, a targeted approach to antiviral prophylaxis contained the spread of influenza in a summer camp setting.

Oseltamivir for treatment and prevention of pandemic influenza A/H1N1 virus infection in households, Milwaukee, 2009

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Miller Joel C

2010-07-01

Full Text Available Abstract Background During an influenza pandemic, a substantial proportion of transmission is thought to occur in households. We used data on influenza progression in individuals and their contacts collected by the City of Milwaukee Health Department (MHD to study the transmission of pandemic influenza A/H1N1 virus in 362 households in Milwaukee, WI, and the effects of oseltamivir treatment and chemoprophylaxis. Methods 135 households had chronological information on symptoms and oseltamivir usage for all household members. The effect of oseltamivir treatment and other factors on the household secondary attack rate was estimated using univariate and multivariate logistic regression with households as the unit of analysis. The effect of oseltamivir treatment and other factors on the individual secondary attack rate was estimated using univariate and multivariate logistic regression with individual household contacts as the unit of analysis, and a generalized estimating equations approach was used to fit the model to allow for clustering within households. Results Oseltamivir index treatment on onset day or the following day (early treatment was associated with a 42% reduction (OR: 0.58, 95% CI: 0.19, 1.73 in the odds of one or more secondary infections in a household and a 50% reduction (OR: 0.5, 95% CI: 0.17, 1.46 in the odds of a secondary infection in individual contacts. The confidence bounds are wide due to a small sample of households with early oseltamivir index usage - in 29 such households, 5 had a secondary attack. Younger household contacts were at higher risk of infection (OR: 2.79, 95% CI: 1.50-5.20. Conclusions Early oseltamivir treatment may be beneficial in preventing H1N1pdm influenza transmission; this may have relevance to future control measures for influenza pandemics. Larger randomized trials are needed to confirm this finding statistically.

SIALIDASE (NEURAMINIDASE) OF CORYNEBACTERIUM DIPHTHERIAE.

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WARREN, L; SPEARING, C W

1963-11-01

Warren, Leonard (National Institute of Arthritis and Metabolic Diseases, Bethesda, Md.) and C. W. Spearing. Sialidase (neuraminidase) of Corynebacterium diphtheriae. J. Bacteriol. 86:950-955. 1963.-The characteristics of a sialidase produced by Corynebacterium diphtheriae were studied. The enzyme was partially purified from preparations of diphtheria toxin on a column of Sephadex G-75. By this means the lethal factor of diphtheria toxin was separated, in part, from the sialidase activity. There appeared to be a close immunological relationship between the sialidases of C. diphtheriae and clostridia, since a preparation of diphtheria antitoxin was as effective an inhibitor of diphtheria sialidase as of the sialidase of three species of clostridia. Conversely, antitoxin to clostridia inhibited diphtheria sialidase. Diphtheria antitoxin was essentially inactive toward influenza virus sialidase, and was completely inactive against purified sialidase of Vibrio cholerae. Removal of sialic acid from the proteins in a preparation of diphtheria antitoxin did not alter the inhibitory activity of the antitoxin against diphtheria sialidase. The enzyme operated optimally at pH 5.5 and did not require calcium ions for activity. The substrate specificity of diphtheria sialidase appears to be the same as that of other previously described sialidases.

Biodistribution and metabolism of the anti-influenza drug [{sup 11}C]oseltamivir and its active metabolite [{sup 11}C]Ro 64-0802 in mice

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Hatori, Akiko; Arai, Takuya; Yanamoto, Kazuhiko; Yamasaki, Tomoteru; Kawamura, Kazunori; Yui, Joji; Konno, Fujiko; Nakao, Ryuji; Suzuki, Kazutoshi [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences (NIRS), Inage-ku, Chiba 263-8555 (Japan); Zhang Mingrong [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences (NIRS), Inage-ku, Chiba 263-8555 (Japan)], E-mail: zhang@nirs.go.jp

2009-01-15

Introduction: Oseltamivir phosphate (Tamiflu) is an orally active anti-influenza drug, which is hydrolyzed by esterase to its carboxylate metabolite Ro 64-0802 with potent activity to inhibit the influenza virus. The abnormal behavior and death associated with the use of oseltamivir have developed into a major problem in Japan where Tamiflu is often prescribed for seasonal influenza. It is critical to determine the amount of oseltamivir and Ro 64-0802 in the human brain and to elucidate the relationship between their amounts and neuropsychiatric side effects. The aim of this study was to evaluate [{sup 11}C]oseltamivir and [{sup 11}C]Ro 64-0802 in mice as promising positron emission tomography (PET) ligands for measuring their amounts in living brains. Methods: Whole-body biodistribution of [{sup 11}C]oseltamivir and [{sup 11}C]Ro 64-0802 was determined in mice using the dissection method and micro-PET. In vitro and in vivo metabolite assay was performed in the plasma and brain of mice. Results: Between 1 and 60 min after injection of [{sup 11}C]oseltamivir and [{sup 11}C]Ro 64-0802, 0.20-0.06% and 0.39-0.03% ID/g were detected in the mouse brains, respectively (dissection method). Radioactivity concentrations in the living brains between 0 and 90 min after injection were measured at standardized uptake values of 0.25-0.05 for [{sup 11}C]oseltamivir and 0.38-0.02 for [{sup 11}C]Ro 64-0802 (micro-PET). In vivo metabolite assay demonstrated the presence of [{sup 11}C]oseltamivir and [{sup 11}C]Ro 64-0802 in the brains after [{sup 11}C]oseltamivir injection. Conclusion: This study determined the distribution and metabolism of [{sup 11}C]oseltamivir and [{sup 11}C]Ro 64-0802 in mice. PET could be used to measure their amounts in the living brain and to elucidate the relationship between the amounts in the brain and the side effects of Tamiflu in the central nervous system.

Cloning of neuraminidase (NA) gene and identification of its antiviral ...

African Journals Online (AJOL)

Neuraminidase not only works as an antigen, inducing target-specific antibodies, but also plays a role of enzyme activity and destroys the sialic acid receptor required by virus infection of the host cell surface which protects the host from virus damage. In order to explore a new idea to use neuraminidase (NA) gene and ...

Effect of Neuraminidase Inhibitor–Resistant Mutations on Pathogenicity of Clade 2.2 A/Turkey/15/06 (H5N1) Influenza Virus in Ferrets

OpenAIRE

Ilyushina, Natalia A.; Seiler, Jon P.; Rehg, Jerold E.; Webster, Robert G.; Govorkova, Elena A.

2010-01-01

The acquisition of neuraminidase (NA) inhibitor resistance by H5N1 influenza viruses has serious clinical implications, as this class of drugs can be an essential component of pandemic control measures. The continuous evolution of the highly pathogenic H5N1 influenza viruses results in the emergence of natural NA gene variations whose impact on viral fitness and NA inhibitor susceptibility are poorly defined. We generated seven genetically stable recombinant clade 2.2 A/Turkey/15/06-like (H5N...

[Naturally occurring oseltamivir resistance in influenza A.

DEFF Research Database (Denmark)

Madsen, Laura; Nielsen, Alex; Lundgren, Jens

2010-01-01

in the development of resistance. The best prevention strategy remains vaccination of the general population to avoid immunity. Future antiviral treatment calls for knowledge about resistance to existing types of influenza and the availability of all three types of antiviral medication. Udgivelsesdato: 2010-Aug......During the last two influenza seasons, one of the predominant influenza A types (H1N1) has developed complete resistance to oseltamivir, the primary treatment option. The virus does, however, remain sensitive to zanamavir and amantadine. There is no unequivocal explanation for this slide...

[Naturally occurring oseltamivir resistance in influenza A.

DEFF Research Database (Denmark)

Madsen, Laura; Nielsen, Alex; Lundgren, Jens

2010-01-01

During the last two influenza seasons, one of the predominant influenza A types (H1N1) has developed complete resistance to oseltamivir, the primary treatment option. The virus does, however, remain sensitive to zanamavir and amantadine. There is no unequivocal explanation for this slide...... in the development of resistance. The best prevention strategy remains vaccination of the general population to avoid immunity. Future antiviral treatment calls for knowledge about resistance to existing types of influenza and the availability of all three types of antiviral medication. Udgivelsesdato: 2010-Aug...

Antiviral agents: structural basis of action and rational design.

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Menéndez-Arias, Luis; Gago, Federico

2013-01-01

During the last 30 years, significant progress has been made in the development of novel antiviral drugs, mainly crystallizing in the establishment of potent antiretroviral therapies and the approval of drugs inhibiting hepatitis C virus replication. Although major targets of antiviral intervention involve intracellular processes required for the synthesis of viral proteins and nucleic acids, a number of inhibitors blocking virus assembly, budding, maturation, entry or uncoating act on virions or viral capsids. In this review, we focus on the drug discovery process while presenting the currently used methodologies to identify novel antiviral drugs by using a computer-based approach. We provide examples illustrating structure-based antiviral drug development, specifically neuraminidase inhibitors against influenza virus (e.g. oseltamivir and zanamivir) and human immunodeficiency virus type 1 protease inhibitors (i.e. the development of darunavir from early peptidomimetic compounds such as saquinavir). A number of drugs in preclinical development acting against picornaviruses, hepatitis B virus and human immunodeficiency virus and their mechanism of action are presented to show how viral capsids can be exploited as targets of antiviral therapy.

A new technique of tritium labelling of neuraminidase from Vibrio cholerae

International Nuclear Information System (INIS)

Keune, D.

1981-01-01

By acylation of the free amino groups of the enzyme neuraminidase from Vibrio cholerae using N-[(2,3 - 3 H)-propionyloxy]-succinimide it was possible to transfer tritium-labelled propionyl groups to free amino groups of the enzyme glycoprotein. It was established by preliminary trials that a certain minimum concentration of protein was necessary to achieve a satisfactory degree of acylation. After the various processing stages, the acylation of neuraminidase with N-[(2,3 - 3 H)-propionyloxy]-succinimide led to the incorporation of 5.26 μCi radioactivity per mg enzymal protein. Comparison with a known method for neuraminidase labelling showed that the new process is more effective in terms of incorporation of radioactivity. Enzyme activity is inhibited by both methods. (orig./MG) [de

Using high-throughput sequencing to leverage surveillance of genetic diversity and oseltamivir resistance: a pilot study during the 2009 influenza A(H1N1 pandemic.

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Juan Téllez-Sosa

Full Text Available BACKGROUND: Influenza viruses display a high mutation rate and complex evolutionary patterns. Next-generation sequencing (NGS has been widely used for qualitative and semi-quantitative assessment of genetic diversity in complex biological samples. The "deep sequencing" approach, enabled by the enormous throughput of current NGS platforms, allows the identification of rare genetic viral variants in targeted genetic regions, but is usually limited to a small number of samples. METHODOLOGY AND PRINCIPAL FINDINGS: We designed a proof-of-principle study to test whether redistributing sequencing throughput from a high depth-small sample number towards a low depth-large sample number approach is feasible and contributes to influenza epidemiological surveillance. Using 454-Roche sequencing, we sequenced at a rather low depth, a 307 bp amplicon of the neuraminidase gene of the Influenza A(H1N1 pandemic (A(H1N1pdm virus from cDNA amplicons pooled in 48 barcoded libraries obtained from nasal swab samples of infected patients (n  =  299 taken from May to November, 2009 pandemic period in Mexico. This approach revealed that during the transition from the first (May-July to second wave (September-November of the pandemic, the initial genetic variants were replaced by the N248D mutation in the NA gene, and enabled the establishment of temporal and geographic associations with genetic diversity and the identification of mutations associated with oseltamivir resistance. CONCLUSIONS: NGS sequencing of a short amplicon from the NA gene at low sequencing depth allowed genetic screening of a large number of samples, providing insights to viral genetic diversity dynamics and the identification of genetic variants associated with oseltamivir resistance. Further research is needed to explain the observed replacement of the genetic variants seen during the second wave. As sequencing throughput rises and library multiplexing and automation improves, we foresee that

Combined quantum mechanics/molecular mechanics (QM/MM) simulations for protein-ligand complexes: free energies of binding of water molecules in influenza neuraminidase.

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Woods, Christopher J; Shaw, Katherine E; Mulholland, Adrian J

2015-01-22

The applicability of combined quantum mechanics/molecular mechanics (QM/MM) methods for the calculation of absolute binding free energies of conserved water molecules in protein/ligand complexes is demonstrated. Here, we apply QM/MM Monte Carlo simulations to investigate binding of water molecules to influenza neuraminidase. We investigate five different complexes, including those with the drugs oseltamivir and peramivir. We investigate water molecules in two different environments, one more hydrophobic and one hydrophilic. We calculate the free-energy change for perturbation of a QM to MM representation of the bound water molecule. The calculations are performed at the BLYP/aVDZ (QM) and TIP4P (MM) levels of theory, which we have previously demonstrated to be consistent with one another for QM/MM modeling. The results show that the QM to MM perturbation is significant in both environments (greater than 1 kcal mol(-1)) and larger in the more hydrophilic site. Comparison with the same perturbation in bulk water shows that this makes a contribution to binding. The results quantify how electronic polarization differences in different environments affect binding affinity and also demonstrate that extensive, converged QM/MM free-energy simulations, with good levels of QM theory, are now practical for protein/ligand complexes.

Neuraminidases 3 and 4 regulate neuronal function by catabolizing brain gangliosides.

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Pan, Xuefang; De Aragão, Camila De Britto Pará; Velasco-Martin, Juan P; Priestman, David A; Wu, Harry Y; Takahashi, Kohta; Yamaguchi, Kazunori; Sturiale, Luisella; Garozzo, Domenico; Platt, Frances M; Lamarche-Vane, Nathalie; Morales, Carlos R; Miyagi, Taeko; Pshezhetsky, Alexey V

2017-08-01

Gangliosides (sialylated glycolipids) play an essential role in the CNS by regulating recognition and signaling in neurons. Metabolic blocks in processing and catabolism of gangliosides result in the development of severe neurologic disorders, including gangliosidoses manifesting with neurodegeneration and neuroinflammation. We demonstrate that 2 mammalian enzymes, neuraminidases 3 and 4, play important roles in catabolic processing of brain gangliosides by cleaving terminal sialic acid residues in their glycan chains. In neuraminidase 3 and 4 double-knockout mice, G M3 ganglioside is stored in microglia, vascular pericytes, and neurons, causing micro- and astrogliosis, neuroinflammation, accumulation of lipofuscin bodies, and memory loss, whereas their cortical and hippocampal neurons have lower rate of neuritogenesis in vitro Double-knockout mice also have reduced levels of G M1 ganglioside and myelin in neuronal axons. Furthermore, neuraminidase 3 deficiency drastically increased storage of G M2 in the brain tissues of an asymptomatic mouse model of Tay-Sachs disease, a severe human gangliosidosis, indicating that this enzyme is responsible for the metabolic bypass of β-hexosaminidase A deficiency. Together, our results provide the first in vivo evidence that neuraminidases 3 and 4 have important roles in CNS function by catabolizing gangliosides and preventing their storage in lipofuscin bodies.-Pan, X., De Britto Pará De Aragão, C., Velasco-Martin, J. P., Priestman, D. A., Wu, H. Y., Takahashi, K., Yamaguchi, K., Sturiale, L., Garozzo, D., Platt, F. M., Lamarche-Vane, N., Morales, C. R., Miyagi, T., Pshezhetsky, A. V. Neuraminidases 3 and 4 regulate neuronal function by catabolizing brain gangliosides. © FASEB.

Therapeutic targeting of Neu1 sialidase with oseltamivir phosphate (Tamiflu® disables cancer cell survival in human pancreatic cancer with acquired chemoresistance

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O’Shea LK

2014-01-01

Full Text Available Leah K O'Shea,1 Samar Abdulkhalek,1 Stephanie Allison,2 Ronald J Neufeld,2 Myron R Szewczuk11Department of Biomedical and Molecular Sciences, 2Department of Chemical Engineering, Queen's University, Kingston, ON, CanadaBackground: Resistance to drug therapy, along with high rates of metastasis, contributes to the low survival rate in patients diagnosed with pancreatic cancer. An alternate treatment for human pancreatic cancer involving targeting of Neu1 sialidase with oseltamivir phosphate (Tamiflu® was investigated in human pancreatic cancer (PANC1 cells with acquired resistance to cisplatin and gemcitabine. Its efficacy in overcoming the intrinsic resistance of the cell to chemotherapeutics and metastasis was evaluated.Methods: Microscopic imaging, immunocytochemistry, immunohistochemistry, and WST-1 cell viability assays were used to evaluate cell survival, morphologic changes, and expression levels of E-cadherin, N-cadherin, and VE-cadherin before and after treatment with oseltamivir phosphate in PANC1 cells with established resistance to cisplatin, gemcitabine, or a combination of the two agents, and in archived paraffin-embedded PANC1 tumors grown in RAGxCγ double mutant mice.Results: Oseltamivir phosphate overcame the chemoresistance of PANC1 to cisplatin and gemcitabine alone or in combination in a dose-dependent manner, and disabled the cancer cell survival mechanism(s. Oseltamivir phosphate also reversed the epithelial-mesenchymal transition characteristic of the phenotypic E-cadherin to N-cadherin changes associated with resistance to drug therapy. Low-dose oseltamivir phosphate alone or in combination with gemcitabine in heterotopic xenografts of PANC1 tumors growing in RAGxCγ double mutant mice did not prevent metastatic spread to the liver and lung.Conclusion: Therapeutic targeting of Neu1 sialidase with oseltamivir phosphate at the growth factor receptor level disables the intrinsic signaling platform for cancer cell survival

Characterization of the neuraminidase genes from human influenza A viruses circulating in Iran from 2010 to 2015.

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Moasser, Elham; Behzadian, Farida; Moattari, Afagh; Fotouhi, Fatemeh; Zaraket, Hassan

2018-02-01

Characterization of influenza viruses is critical for detection of new emerging variants. Herein, we analyzed the genetic diversity and drug susceptibility of the neuraminidase gene (NAs) expressed by influenza A/H1N1pdm09 and A/H3N2 viruses circulating in Iran from 2010 to 2015. We genetically analyzed the NAs of 38 influenza A/H1N1pdm09 and 35 A/H3N2 isolates. The Iranian A/H1N1pdm09 viruses belonged to seven genogroups/subgenogroups, with the dominant groups being genogroups 6B and 6C. The A/H3N2 isolates fell into six gneogroups/subgenogroups, with the dominant genogroups being 3C and 3C.2a. The most common mutations detected among the A/H1N1pdm09 viruses included N44S, V106I, N200S, and N248D. All H1N1pdm09 viruses were genetically susceptible to the NAIs. However, one A/H1N1pdm09 virus from the 2013-2014 season possessed an NA-S247N mutation, which reduces the susceptibility to oseltamivir. In case of H3N2, none of the analyzed Iranian strains carried a substitution that might affect its susceptibility to NAIs. The ongoing evolution of influenza viruses and the detect of influenza viruses with reduced susceptibility to NAIs warrants continuous monitoring of the circulating strains.

Oseltamivir use and severe abnormal behavior in Japanese children and adolescents with influenza: Is a self-controlled case series study applicable?

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Fukushima, Wakaba; Ozasa, Kotaro; Okumura, Akihisa; Mori, Masaaki; Hosoya, Mitsuaki; Nakano, Takashi; Tanabe, Takuya; Yamaguchi, Naoto; Suzuki, Hiroshi; Mori, Mitsuru; Hatayama, Hideaki; Ochiai, Hirotaka; Kondo, Kyoko; Ito, Kazuya; Ohfuji, Satoko; Nakamura, Yosikazu; Hirota, Yoshio

2017-08-24

Since the 1990s, self-controlled designs including self-controlled case series (SCCS) studies have been occasionally used in post-marketing evaluation of drug or vaccine safety. An SCCS study was tentatively applied to evaluate the relationship between oseltamivir use and abnormal behavior Type A (serious abnormal behavior potentially leading to an accident or harm to another person) in influenza patients. From the original prospective cohort study with approximately 10,000 Japanese children and adolescents with influenza (aged collaborating hospitals/clinics were analyzed. We hypothesized four combination patterns of the effect period (i.e., the period that effect of oseltamivir on occurrence of abnormal behavior Type A is likely) and the control period. Mantel-Haenszel rate ratio (M-H RR) and its 95% confidence interval (CI) were calculated as the relative risk estimate. Among 28 subjects in the SCCS study, 24 subjects (86%) were administered oseltamivir and 4 subjects (14%) were not. Abnormal behavior Type A was more likely to occur in the effect period than the control period in every pattern (M-H RR: 1.90-29.1). We observed the highest estimate when the effect period was set between the initial intake of oseltamivir and T max (M-H RR: 29.1, 95% CI: 4.21-201). Abnormal behavior Type A was more likely to develop up to approximately 30 times during the period between the initial intake of oseltamivir and T max . However, this period overlapped with the early period of influenza where high fever was observed. Since useful approaches to control the influence of the natural disease course of influenza were not available in this study, we could not deny the possibility that abnormal behavior was induced by influenza itself. The SCCS study was not an optimal method to evaluate the relationship between oseltamivir use and abnormal behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combining crystallographic information and an aspherical-atom data bank in the evaluation of the electrostatic interaction energy in an enzyme–substrate complex: influenza neuraminidase inhibition

Energy Technology Data Exchange (ETDEWEB)

Dominiak, Paulina M., E-mail: pdomin@chem.uw.edu.pl [Department of Chemistry, State University of New York at Buffalo, NY 14260 (United States); Department of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warszawa (Poland); Volkov, Anatoliy; Dominiak, Adam P. [Department of Chemistry, State University of New York at Buffalo, NY 14260 (United States); Jarzembska, Katarzyna N. [Department of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warszawa (Poland); Coppens, Philip, E-mail: pdomin@chem.uw.edu.pl [Department of Chemistry, State University of New York at Buffalo, NY 14260 (United States)

2009-05-01

The electrostatic component of the enzyme/inhibitor interaction of a wide range influenza neuraminidases and inhibitors has been analyzed using transferable aspherical-atom densities from a recently compiled databank. Results are subdivided into the contributions of individual active-site residues and different functional groups of the inhibitors, and the effect of the Arg292→Lys mutation is considered. Although electrostatic interactions contribute only a part of the interaction energies between macromolecules, unlike dispersion forces they are highly directional and therefore dominate the nature of molecular packing in crystals and in biological complexes and contribute significantly to differences in inhibition strength among related enzyme inhibitors. In the reported study, a wide range of complexes of influenza neuraminidases with inhibitor molecules (sialic acid derivatives and others) have been analyzed using charge densities from a transferable aspherical-atom data bank. The strongest interactions of the residues are with the acidic group at the C2 position of the inhibitor (∼−300 kJ mol{sup −1} for —COO{sup −} in non-aromatic inhibitors, ∼−120–210 kJ mol{sup −1} for —COO{sup −} in aromatic inhibitors and ∼−450 kJ mol{sup −1} for —PO{sub 3}{sup 2−}) and with the amino and guanidine groups at C4 (∼−250 kJ mol{sup −1}). Other groups contribute less than ∼100 kJ mol{sup −1}. Residues Glu119, Asp151, Glu227, Glu276 and Arg371 show the largest variation in electrostatic energies of interaction with different groups of inhibitors, which points to their important role in the inhibitor recognition. The Arg292→Lys mutation reduces the electrostatic interactions of the enzyme with the acidic group at C2 for all inhibitors that have been studied (SIA, DAN, 4AM, ZMR, G20, G28, G39 and BCZ), but enhances the interactions with the glycerol group at C6 for inhibitors that contain it. This is in agreement with the lower level

A new ion selective electrode method for determination of oseltamivir phosphate (Tamiflu and its pharmaceutical applications

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Salem M. Hamza

2017-02-01

The construction and electrochemical response characteristics of poly vinyl chloride (PVC membrane sensors for the determination of (OP were described. The sensors are based on the use of the ion association complexes of (OP cation with sodium tetraphenylborate–oseltamivir phosphate (NaTPB–OP, tungestosilisate–oseltamivir phosphate (TS–OP, phosphomolbdate–oseltamivir phosphate (PM–OP and phosphotungestate–oseltamivir phosphate (PT–OP as ion exchange sites in the PVC matrix. The performance characteristics of these sensors, which were evaluated according to IUPAC recommendations, reveal a fast, stable and linear response for (OP over the concentration range from 10−5 to 10−2 mol L−1 with cationic slopes of 51.5 ± 0.3, 50 ± 0.5, 55 ± 0.2 and 50 ± 0.4 mV per decade across an extended OP concentration range from 1.0 × 10−6 to 1.0 × 10−2 mol L−1 for NaTPB–OP, TS–OP, PM–OP and PT–OP, respectively. The direct potentiometric determination of (OP using the proposed sensors gave average recoveries of 99.9, 99.8, 99.9 and 99.7 for NaTPB–OP, TS–OP, PM–OP and PT–OP, respectively. The sensors are used for determination of (OP in tablets. The method was successfully applied to commercial pharmaceuticals, Tamiflu. Validation of the method shows suitability of the proposed sensors for use in the quality control assessment of (OP. The developed method was found to be simple, accurate and precise when compared with a reported HPLC method.

Synthesis, Isolation and Characterization of Process-Related Impurities in Oseltamivir Phosphate

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Yogesh Kumar Sharma

2012-01-01

Full Text Available Three known impurities in oseltamivir phosphate bulk drug at level 0.1% (ranging from 0.05-0.1% were detected by gradient reverse phase high performance liquid chromatography. These impurities were preliminarily identified by the mass number of the impurities. Different experiments were conducted and finally the known impurities were synthesized and characterized.

Post-marketing safety and effectiveness evaluation of the intravenous anti-influenza neuraminidase inhibitor peramivir (I): a drug use investigation.

Science.gov (United States)

Komeda, Takuji; Ishii, Shingo; Itoh, Yumiko; Ariyasu, Yasuyuki; Sanekata, Masaki; Yoshikawa, Takayoshi; Shimada, Jingoro

2014-11-01

Peramivir is the only intravenous formulation among anti-influenza neuraminidase inhibitors currently available. Peramivir was approved for manufacturing and marketing in Japan in January 2010. We conducted a drug use investigation of peramivir from October 2010 to February 2012 and evaluated its safety and effectiveness under routine clinical settings. We collected data of 1309 patients from 189 facilities across Japan and examined safety in 1174 patients and effectiveness in 1158 patients. In total, 143 adverse events were observed with an incidence rate of 7.33% (86/1174). Of these, 78 events were adverse drug reactions (ADRs) with an incidence rate of 4.34% (51/1174). The most frequently reported ADRs were diarrhea, vomiting, and nausea, with incidence rates of 1.87% (22/1174), 0.85% (10/1174), and 0.68% (8/1174), respectively. Moreover, no ADR was reported as serious. ADR onset was within 3 days after the start of peramivir administration in 91.0% (71 events) of the 78 ADRs, and ADRs were resolved or improved within 7 days after onset in 96.2% (75 events) of the 78 ADRs. Neither patient characteristics nor treatment factors appeared to significantly affect drug safety. With regard to effectiveness, the median time to alleviation of both influenza symptoms and fever was 3 days, including the first day of administration. The present study demonstrates the safety and effectiveness of peramivir under routine clinical settings. Copyright © 2014 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Analyzing the interaction of a herbal compound Andrographolide from Andrographis paniculata as a folklore against swine flu (H1N1

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Chandrabhan Seniya

2014-09-01

Full Text Available Objective: To find new bioactive molecules for the treatment of swine flu. Methods: The present study is an attempt to elucidate inhibition potential of andrographolide and its derivatives along with an associated binding mechanism through virtual screening and molecular docking simulation studies. Results: Our findings revealed structural conformation changes in 150 loop, secondary sialic acid binding site residues of ACZ97474 {Neuraminidase (A/Blore/NIV236/2009(H1N1}. Andrographolide have been identified as the highest binging energy of -1 0.88 Kcal/mol, 3 hydrogen bond interactions (Arg152, Lys150, and Gly197, total intermolecular energy of -12.07 Kcal/mol with bioactivity value (Ki of 10.59 nmol/L, while the Food and Drug Admistraton approved drug Oseltamivir and Zanamivir have shown 2 and 4 hydrogen bond interactions with binding energies of -6.28 Kcal/mol and -7.73Kcal/mol, respectively, which is higher than andrographolide. The guanidine group of Arg152 has binding affinities to the hydrophilic nature of the inhibitors (-OH and =O groups, as identified by docking of andrographolide (CID: 5318517 on neuraminidase. Conclusions: Hence, andrographolide has the potential to inhibit neuraminidase activity of H1N1 and may be used as an alternative medicinal therapy for swine flu positive patient. With potent antiviral activity and a potentially new mechanism of action, andrographolide may warrant further evaluation as a possible therapy for influenza.

Influenza virus drug resistance: a time-sampled population genetics perspective.

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Matthieu Foll

2014-02-01

Full Text Available The challenge of distinguishing genetic drift from selection remains a central focus of population genetics. Time-sampled data may provide a powerful tool for distinguishing these processes, and we here propose approximate Bayesian, maximum likelihood, and analytical methods for the inference of demography and selection from time course data. Utilizing these novel statistical and computational tools, we evaluate whole-genome datasets of an influenza A H1N1 strain in the presence and absence of oseltamivir (an inhibitor of neuraminidase collected at thirteen time points. Results reveal a striking consistency amongst the three estimation procedures developed, showing strongly increased selection pressure in the presence of drug treatment. Importantly, these approaches re-identify the known oseltamivir resistance site, successfully validating the approaches used. Enticingly, a number of previously unknown variants have also been identified as being positively selected. Results are interpreted in the light of Fisher's Geometric Model, allowing for a quantification of the increased distance to optimum exerted by the presence of drug, and theoretical predictions regarding the distribution of beneficial fitness effects of contending mutations are empirically tested. Further, given the fit to expectations of the Geometric Model, results suggest the ability to predict certain aspects of viral evolution in response to changing host environments and novel selective pressures.

A Review of the Antiviral Susceptibility of Human and Avian Influenza Viruses over the Last Decade

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Oh, Ding Yuan; Hurt, Aeron C.

2014-01-01

Antivirals play an important role in the prevention and treatment of influenza infections, particularly in high-risk or severely ill patients. Two classes of influenza antivirals have been available in many countries over the last decade (2004–2013), the adamantanes and the neuraminidase inhibitors (NAIs). During this period, widespread adamantane resistance has developed in circulating influenza viruses rendering these drugs useless, resulting in the reliance on the most widely available NAI, oseltamivir. However, the emergence of oseltamivir-resistant seasonal A(H1N1) viruses in 2008 demonstrated that NAI-resistant viruses could also emerge and spread globally in a similar manner to that seen for adamantane-resistant viruses. Previously, it was believed that NAI-resistant viruses had compromised replication and/or transmission. Fortunately, in 2013, the majority of circulating human influenza viruses remain sensitive to all of the NAIs, but significant work by our laboratory and others is now underway to understand what enables NAI-resistant viruses to retain the capacity to replicate and transmit. In this review, we describe how the susceptibility of circulating human and avian influenza viruses has changed over the last ten years and describe some research studies that aim to understand how NAI-resistant human and avian influenza viruses may emerge in the future. PMID:24800107

Oseltamivir prescription and regulatory actions vis-à-vis abnormal behavior risk in Japan: drug utilization study using a nationwide pharmacy database.

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Urushihara, Hisashi; Doi, Yuko; Arai, Masaru; Matsunaga, Toshiyuki; Fujii, Yosuke; Iino, Naoko; Kawamura, Takashi; Kawakami, Koji

2011-01-01

In March 2007, a regulatory advisory was issued in Japan to restrict oseltamivir use in children aged 10-19 years because of safety concerns over abnormal behavior. The effectiveness and validity of regulatory risk minimization actions remain to be reviewed, despite their significant public health implications. To assess the impact of the regulatory actions on prescribing practices and safety reporting. METHODOLOY/PRINICPAL FINDINGS: In this retrospective review of a nationwide pharmacy database, we analyzed 100,344 dispensation records for oseltamivir and zanamivir for the period from November 2006 to March 2009. The time trend in dispensations for these antiviral agents was presented before and after the regulatory actions, contrasted with intensity of media coverage and the numbers of spontaneous adverse reaction reports with regard to antivirals. The 2007 regulatory actions, together with its intense media coverage, reduced oseltamivir dispensation in targeted patients in fiscal year 2008 to 20.4% of that in fiscal year 2006, although influenza activities were comparable between these fiscal years. In contrast, zanamivir dispensation increased approximately nine-fold across all age groups. The number of abnormal behavior reports associated with oseltamivir in children aged 10-19 years decreased from fiscal year 2006 to 2008 (24 to 9 cases); this decline was offset by the increased number of reports of abnormal behavior in children under age 10 (12 to 28 cases). The number of reports associated with zanamivir increased in proportion to increased dispensation of this drug (11 to 114 cases). The 2007 actions effectively reduced oseltamivir prescriptions and the number of reports of abnormal behavior in the targeted group. The observed increase in abnormal behavior reports in oseltamivir patients under age 10 and in zanamivir patients suggests that these patient groups may also be at risk, calling into question the validity of the current discrimination by age and

Oseltamivir prescription and regulatory actions vis-à-vis abnormal behavior risk in Japan: drug utilization study using a nationwide pharmacy database.

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Hisashi Urushihara

Full Text Available BACKGROUND: In March 2007, a regulatory advisory was issued in Japan to restrict oseltamivir use in children aged 10-19 years because of safety concerns over abnormal behavior. The effectiveness and validity of regulatory risk minimization actions remain to be reviewed, despite their significant public health implications. To assess the impact of the regulatory actions on prescribing practices and safety reporting. METHODOLOY/PRINICPAL FINDINGS: In this retrospective review of a nationwide pharmacy database, we analyzed 100,344 dispensation records for oseltamivir and zanamivir for the period from November 2006 to March 2009. The time trend in dispensations for these antiviral agents was presented before and after the regulatory actions, contrasted with intensity of media coverage and the numbers of spontaneous adverse reaction reports with regard to antivirals. The 2007 regulatory actions, together with its intense media coverage, reduced oseltamivir dispensation in targeted patients in fiscal year 2008 to 20.4% of that in fiscal year 2006, although influenza activities were comparable between these fiscal years. In contrast, zanamivir dispensation increased approximately nine-fold across all age groups. The number of abnormal behavior reports associated with oseltamivir in children aged 10-19 years decreased from fiscal year 2006 to 2008 (24 to 9 cases; this decline was offset by the increased number of reports of abnormal behavior in children under age 10 (12 to 28 cases. The number of reports associated with zanamivir increased in proportion to increased dispensation of this drug (11 to 114 cases. CONCLUSIONS/SIGNIFICANCE: The 2007 actions effectively reduced oseltamivir prescriptions and the number of reports of abnormal behavior in the targeted group. The observed increase in abnormal behavior reports in oseltamivir patients under age 10 and in zanamivir patients suggests that these patient groups may also be at risk, calling into question

Interdisciplinary pharmacometrics linking oseltamivir pharmacology, influenza epidemiology and health economics to inform antiviral use in pandemics.

Science.gov (United States)

Kamal, Mohamed A; Smith, Patrick F; Chaiyakunapruk, Nathorn; Wu, David B C; Pratoomsoot, Chayanin; Lee, Kenneth K C; Chong, Huey Yi; Nelson, Richard E; Nieforth, Keith; Dall, Georgina; Toovey, Stephen; Kong, David C M; Kamauu, Aaron; Kirkpatrick, Carl M; Rayner, Craig R

2017-07-01

A modular interdisciplinary platform was developed to investigate the economic impact of oseltamivir treatment by dosage regimen under simulated influenza pandemic scenarios. The pharmacology module consisted of a pharmacokinetic distribution of oseltamivir carboxylate daily area under the concentration-time curve at steady state (simulated for 75 mg and 150 mg twice daily regimens for 5 days) and a pharmacodynamic distribution of viral shedding duration obtained from phase II influenza inoculation data. The epidemiological module comprised a susceptible, exposed, infected, recovered (SEIR) model to which drug effect on the basic reproductive number (R 0 ), a measure of transmissibility, was linked by reduction of viral shedding duration. The number of infected patients per population of 100 000 susceptible individuals was simulated for a series of pandemic scenarios, varying oseltamivir dose, R 0 (1.9 vs. 2.7), and drug uptake (25%, 50%, and 80%). The number of infected patients for each scenario was entered into the health economics module, a decision analytic model populated with branch probabilities, disease utility, costs of hospitalized patients developing complications, and case-fatality rates. Change in quality-adjusted life years was determined relative to base case. Oseltamivir 75 mg relative to no treatment reduced the median number of infected patients, increased change in quality-adjusted life years by deaths averted, and was cost-saving under all scenarios; 150 mg relative to 75 mg was not cost effective in low transmissibility scenarios but was cost saving in high transmissibility scenarios. This methodological study demonstrates proof of concept that the disciplines of pharmacology, disease epidemiology and health economics can be linked in a single quantitative framework. © 2017 The British Pharmacological Society.

European guidelines for prevention and management of influenza in hematopoietic stem cell transplantation and leukemia patients: summary of ECIL-4 (2011), on behalf of ECIL, a joint venture of EBMT, EORTC, ICHS, and ELN.

Science.gov (United States)

Engelhard, D; Mohty, B; de la Camara, R; Cordonnier, C; Ljungman, P

2013-06-01

Influenza may cause severe disease and mortality in leukemia patients and in hematopoietic stem cell transplantation recipients. The 4th European Conference of Infections in Leukemia (ECIL-4) has developed evidence-based guidelines for prevention and management of influenza infections in these patients. Real-time reverse-transcription polymerase chain reaction is the diagnostic test of choice, as it is the most sensitive and specific test for influenza. The risks for severe influenza and fatal outcome include lymphopenia, older age, influenza soon after transplantation or chemotherapy, steroid treatment, and lack of early antiviral therapy. Neuraminidase inhibitors (oral oseltamivir or inhalation of zanamivir) are currently the most effective therapeutic agents for influenza. Main preventive measures include annual vaccination of patients, household contacts, and hospital staff. This review summarizes ECIL-4's main recommendations. © 2013 John Wiley & Sons A/S.

Combination Chemotherapy for Influenza

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Robert G. Webster

2010-07-01

Full Text Available The emergence of pandemic H1N1 influenza viruses in April 2009 and the continuous evolution of highly pathogenic H5N1 influenza viruses underscore the urgency of novel approaches to chemotherapy for human influenza infection. Anti-influenza drugs are currently limited to the neuraminidase inhibitors (oseltamivir and zanamivir and to M2 ion channel blockers (amantadine and rimantadine, although resistance to the latter class develops rapidly. Potential targets for the development of new anti-influenza agents include the viral polymerase (and endonuclease, the hemagglutinin, and the non-structural protein NS1. The limitations of monotherapy and the emergence of drug-resistant variants make combination chemotherapy the logical therapeutic option. Here we review the experimental data on combination chemotherapy with currently available agents and the development of new agents and therapy targets.

Zanamivir immobilized magnetic beads for voltammetric measurement of neuraminidase at gold-modified boron doped diamond electrode

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Wahyuni, Wulan Tri, E-mail: wulantriws@gmail.com [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, Kampus IPB Darmaga, Bogor 16680 (Indonesia); Department of Chemistry, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Ivandini, Tribidasari A.; Saepudin, Endang [Department of Chemistry, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Einaga, Yasuaki [Department of Chemistry, Faculty of Science and Technology, Keio University, Hiyoshi 3-14-1, Yokohama 223-8522 (Japan); CREST, JST, 3-14-1 Hiyoshi, Yokohama 223-8522 (Japan)

2016-04-19

Biomolecule modified magnetic beads has been widely used in separation and sensing process. This study used streptavidin modified magnetic beads to immobilize biotin modified zanamivir. Biotin-streptavidin affinity facilitates immobilization of zanamivir on magnetic beads. Then interaction of zanamivir and neuraminidase was adopted as basic for enzyme detection. Detection of neuraminidase was performed at gold modified BDD using cyclic voltammetry technique. The measurement was carried out based on alteration of electrochemical signals of working electrode as neuraminidase response. The result showed that zanamivir was successfully immobilized on magnetic beads. The optimum amount of magnetic beads for zanamivir immobilization was 120 ug. Linear responses of neuraminidase were detected in concentration range of 0-15 mU. Detection limit (LOD) of measurement was 2.32 mU (R2 = 0.959) with precision as % RSD of 1.41%. Measurement of neuraminidase on magnetic beads could be also performed in the presence of mucin matrix. The linearity range was 0-8 mU with LOD of 0.64 mU (R2 = 0.950) and % RSD of 7.25%.

Combined administration of oseltamivir and hochu-ekki-to (TJ-41) dramatically decreases the viral load in lungs of senescence-accelerated mice during influenza virus infection.

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Ohgitani, Eriko; Kita, Masakazu; Mazda, Osam; Imanishi, Jiro

2014-02-01

To enhance the effect of anti-influenza-virus agent treatment, the effect of combined administration of oseltamivir phosphate and hochu-ekki-to (Japanese traditional herbal medicine, HET) on early viral clearance was examined. Senescence-accelerated mice were given HET in drinking water for 2 weeks, followed by intranasal infection with influenza A virus strain PR8. After 4 hours of infection, oseltamivir was administered orally for 5 days. The viral loads in the lungs of the group receiving combined treatment were dramatically lower when compared with the viral loads in the lungs of the group receiving oseltamivir alone. HET significantly increased the induction of IL-1β and TNF-α in the lungs of PR8-infected mice and stimulated alveolar macrophage phagocytosis. From these results, we conclude that these functions may be responsible the increased effect on viral load reduction. Here, we show that the combined administration of oseltamivir and HET is very useful for influenza treatment in senescence-accelerated mice.

Avian influenza A viruses in birds of the order Psittaciformes: reports on virus isolations, transmission experiments and vaccinations and initial studies on innocuity and efficacy of oseltamivir in ovo.

Science.gov (United States)

Kaleta, E F; Blanco Peña, K M; Yilmaz, A; Redmann, T; Hofheinz, S

2007-07-01

Birds of the order Psittaciformes are - besides chickens, turkeys and other birds - also susceptible to infection with avian influenza A viruses (AIV) and succumb following severe disease within one week. Published data prove that various parakeets, amazons, cockatoos, African grey parrots and budgerigars (genera Barnardius, Psittacula, Cacatua, Eolophus, Amazona, Myiopsitta, Psittacus and Melopsittacus) were found dead following natural infections. Natural infections of highly pathogenic avian influenza viruses (HPAIV) of the haemagglutinin subtypes H5 and H7 cause severe disease and high rates of mortality. Experimental transmission studies with AlVs of the subtypes H5 and H7 confirm these data. Viruses of the subtypes H3N8, H4N6, H4N8, H11N6 and H11N8 may cause also clinical signs and occasionally losses in naturally infected psittacine birds. Clinical signs and losses were also noted following experimental infection of budgerigars with a H4N6 virus. In the EU and in other countries, vaccination of exposed exotic and rare birds and poultry is a possible and an acceptable measure to provide protection. Currently, the EU Commission accepts inactivated adjuvanted vaccines whereas in some other countries recently developed vector vaccines are applied. However, birds remain susceptible during the time interval between application of any vaccine and the development of immunity. This critical period can be bridged with antiviral drugs. Our in ovo studies demonstrate that the neuraminidase inhibitor oseltamivir is non-toxic for chicken embryos at concentrations of 0.1, 1.0 and 10.0 mg/kg body weight. These dosages prevented entirely the replication of a HPAIV of the subtype H7N1 when this drug is given shortly prior to, simultaneously or soon after inoculation of chicken embryos with this AIV. Thus, we speculate that exposed valuable birds such as psittacines at risk can be successfully treated.

Compliance to oseltamivir among two populations in Oxfordshire, United Kingdom affected by influenza A(H1N1pdm09, November 2009--a waste water epidemiology study.

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Andrew C Singer

Full Text Available Antiviral provision remains the focus of many pandemic preparedness plans, however, there is considerable uncertainty regarding antiviral compliance rates. Here we employ a waste water epidemiology approach to estimate oseltamivir (Tamiflu® compliance. Oseltamivir carboxylate (oseltamivir's active metabolite was recovered from two waste water treatment plant (WWTP catchments within the United Kingdom at the peak of the autumnal wave of the 2009 Influenza A (H1N1pdm09 pandemic. Predictions of oseltamivir consumption from detected levels were compared with two sources of national government statistics to derive compliance rates. Scenario and sensitivity analysis indicated between 3-4 and 120-154 people were using oseltamivir during the study period in the two WWTP catchments and a compliance rate between 45-60%. With approximately half the collected antivirals going unused, there is a clear need to alter public health messages to improve compliance. We argue that a near real-time understanding of drug compliance at the scale of the waste water treatment plant (hundreds to millions of people can potentially help public health messages become more timely, targeted, and demographically sensitive, while potentially leading to less mis- and un-used antiviral, less wastage and ultimately a more robust and efficacious pandemic preparedness plan.

Post-marketing safety and effectiveness evaluation of the intravenous anti-influenza neuraminidase inhibitor peramivir. II: a pediatric drug use investigation.

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Komeda, Takuji; Ishii, Shingo; Itoh, Yumiko; Ariyasu, Yasuyuki; Sanekata, Masaki; Yoshikawa, Takayoshi; Shimada, Jingoro

2015-03-01

Peramivir is the only intravenous formulation among anti-influenza neuraminidase inhibitors currently available. Peramivir was approved for manufacturing and marketing in Japan in January 2010. In October 2010, an additional indication for pediatric use was approved. We conducted a pediatric drug use investigation of peramivir from October 2010 to February 2012 and evaluated its real-world safety and effectiveness in pediatric patients. We collected the data of 1254 peramivir-treated pediatric patients from 161 facilities across Japan and examined the safety in 1199 patients and effectiveness in 1188 patients. In total, 245 adverse events were observed with an incidence rate of 14.01% (168/1199). Of these, 115 events were adverse drug reactions (ADRs) with an incidence rate of 7.67% (92/1199). Common ADRs were diarrhea and abnormal behavior, with incidence rates of 2.50% (30/1199) and 2.25% (27/1199), respectively. Fourteen serious ADRs were observed in 12 patients (1.00%), including 5 cases each of abnormal behavior and neutrophil count decreased. While 87.0% (100 events) of ADRs occurred within 3 days after the initiation of peramivir administration, 87.8% (101 events) resolved or improved within 7 days after onset. Multivariate analyses indicated that the presence or absence of underlying diseases/complications was significantly related to ADR incidence. With regard to effectiveness, the median time to alleviation of both influenza symptoms and fever was 3 days, including the first day of administration. Thus, this study confirms the pediatric safety of peramivir without any concerns about effectiveness under routine clinical settings. Copyright © 2014 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

C-Methylated Flavonoids from Cleistocalyx operculatus and Their Inhibitory Effects on Novel Influenza A (H1N1) Neuraminidase

DEFF Research Database (Denmark)

Dao, Trong-Tuan; Tung, Bui-Thanh; Nguyen, Phi-Hung

2010-01-01

As part of an ongoing study focused on the discovery of anti-influenza agents from plants, four new (1-4) and 10 known (5-14) C-methylated flavonoids were isolated from a methanol extract of Cleistocalyx operculatus buds using an influenza H1N1 neuraminidase inhibition assay. Compounds 4, 7, 8...... mutant) expressed in 293T cells with IC50 values of 8.15 ± 1.05 and 3.31 ± 1.34 μM, respectively. Compounds 4, 7, 8, and 14 behaved as noncompetitive inhibitors in the kinetic studies. These results indicate that C-methylated flavonoids from C. operculatus have the potential to be developed...

Selective inhibition of influenza virus protein synthesis by inhibitors of DNA function

International Nuclear Information System (INIS)

Minor, P.D.; Dimmock, N.J.

1977-01-01

Various known inhibitors of cellular DNA function were shown to inhibit cellular RNA synthesis and influenza (fowl plague) virus multiplication. The drugs were investigated for their effect upon the synthesis of influenza virus proteins. According to this effect they could be classified with previously studied compounds as follows: Group I (ethidium bromide, proflavine, and N-nitroquinoline-N-oxide) inhibited both viral and cellular protein synthesis; Group II (nogalomycin, daunomycin and α-amanitin) inhibited viral but not cellular protein synthesis, and all viral proteins were inhibited coordinately; Group III (mithramycin, echinomycin, and actinomycin D) inhibited all viral but not cellular protein synthesis at high concentrations, but at a lower critical concentration inhibited the synthesis of viral haemagglutinin, neuraminidase, and M protein preferentially; Group IV(uv irradiation and camptothecin) inhibited the synthesis of viral haemagglutinin, neuraminidase, and M protein, but not other viral proteins, even at high doses. The mode of action of these inhibitors is discussed in relation to the mechanism of the nuclear events upon which influenza virus multiplication is dependent

The use of a rapid assay to detect the neuraminidase production in oral Porphyromonas spp. isolated from dogs and humans.

Science.gov (United States)

de Assis, Paulo R G R; Nakano, Viviane; Senhorinho, Gerusa N A; Avila-Campos, Mario J

2013-09-01

Neuraminidase was produced by 32.1% and 28.5% of Porphyromonas from dogs with and without periodontitis, respectively; and by 31.8% of bacteria from humans. The presence of neuraminidase in Porphyromonas spp. suggests that this enzyme can be involved with the pathogenesis of the periodontal disease, and the use of this assay to detect the neuraminidase production in oral Porphyromonas species is suggested. © 2013.

Consensus QSAR model for identifying novel H5N1 inhibitors.

Science.gov (United States)

Sharma, Nitin; Yap, Chun Wei

2012-08-01

Due to the importance of neuraminidase in the pathogenesis of influenza virus infection, it has been regarded as the most important drug target for the treatment of influenza. Resistance to currently available drugs and new findings related to structure of the protein requires novel neuraminidase 1 (N1) inhibitors. In this study, a consensus QSAR model with defined applicability domain (AD) was developed using published N1 inhibitors. The consensus model was validated using an external validation set. The model achieved high sensitivity, specificity, and overall accuracy along with low false positive rate (FPR) and false discovery rate (FDR). The performance of model on the external validation set and training set were comparable, thus it was unlikely to be overfitted. The low FPR and low FDR will increase its accuracy in screening large chemical libraries. Screening of ZINC library resulted in 64,772 compounds as probable N1 inhibitors, while 173,674 compounds were defined to be outside the AD of the consensus model. The advantage of the current model is that it was developed using a large and diverse dataset and has a defined AD which prevents its use on compounds that it is not capable of predicting. The consensus model developed in this study is made available via the free software, PaDEL-DDPredictor.

Neuraminidase treatment of respiratory syncytial virus-infected cells or virions, but not target cells, enhances cell-cell fusion and infection

International Nuclear Information System (INIS)

Barretto, Naina; Hallak, Louay K.; Peeples, Mark E.

2003-01-01

Respiratory syncytial virus (RSV) infection of HeLa cells induces fusion, but transient expression of the three viral glycoproteins induces fusion poorly, if at all. We found that neuraminidase treatment of RSV-infected cells to remove sialic acid (SA) increases fusion dramatically and that the same treatment of transiently transfected cells expressing the three viral glycoproteins, or even cells expressing the fusion (F) protein alone, results in easily detectable fusion. Neuraminidase treatment of the effector cells, expressing the viral glycoproteins, enhanced fusion while treatment of the target cells did not. Likewise, infectivity was increased by treating virions with neuraminidase, but not by treating target cells. Reduction of charge repulsion by removal of the negatively charged SA is unlikely to explain this effect, since removal of negative charges from either membrane would reduce charge repulsion. Infection with neuraminidase-treated virus remained heparan-sulfate-dependent, indicating that a novel attachment mechanism is not revealed by SA removal. Interestingly, neuraminidase enhancement of RSV infectivity was less pronounced in a virus expressing both the G and the F glycoproteins, compared to virus expressing only the F glycoprotein, possibly suggesting that the G protein sterically hinders access of the neuraminidase to its fusion-enhancing target

The assembly of GM1 glycolipid- and cholesterol-enriched raft-like membrane microdomains is important for giardial encystation.

Science.gov (United States)

De Chatterjee, Atasi; Mendez, Tavis L; Roychowdhury, Sukla; Das, Siddhartha

2015-05-01

Although encystation (or cyst formation) is an important step of the life cycle of Giardia, the cellular events that trigger encystation are poorly understood. Because membrane microdomains are involved in inducing growth and differentiation in many eukaryotes, we wondered if these raft-like domains are assembled by this parasite and participate in the encystation process. Since the GM1 ganglioside is a major constituent of mammalian lipid rafts (LRs) and known to react with cholera toxin B (CTXB), we used Alexa Fluor-conjugated CTXB and GM1 antibodies to detect giardial LRs. Raft-like structures in trophozoites are located in the plasma membranes and on the periphery of ventral discs. In cysts, however, they are localized in the membranes beneath the cyst wall. Nystatin and filipin III, two cholesterol-binding agents, and oseltamivir (Tamiflu), a viral neuraminidase inhibitor, disassembled the microdomains, as evidenced by reduced staining of trophozoites with CTXB and GM1 antibodies. GM1- and cholesterol-enriched LRs were isolated from Giardia by density gradient centrifugation and found to be sensitive to nystatin and oseltamivir. The involvement of LRs in encystation could be supported by the observation that raft inhibitors interrupted the biogenesis of encystation-specific vesicles and cyst production. Furthermore, culturing of trophozoites in dialyzed medium containing fetal bovine serum (which is low in cholesterol) reduced raft assembly and encystation, which could be rescued by adding cholesterol from the outside. Our results suggest that Giardia is able to form GM1- and cholesterol-enriched lipid rafts and these raft domains are important for encystation. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Outcomes of Oseltamivir Treatment for H1N1 Infection During Pregnancy: A Retrospective Study

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Nermin Akdemir

2011-04-01

CONCLUSION: In this retrospective, study, we found that, H1N1 infection during pregnancy has a good prognosis and without complication for maternal health. Although oseltamivir therapy is safe in pregnant women, it can be associated with cardiac structural cardiac malformations in H1N1 infected pregnancy newborns

The rapid identification of human influenza neuraminidase N1 and N2 subtypes by ELISA.

Science.gov (United States)

Barr, I G; McCaig, M; Durrant, C; Shaw, R

2006-11-10

An ELISA assay was developed to allow the rapid and accurate identification of human influenza A N1 and N2 neuraminidases. Initial testing using a fetuin pre-coating of wells correctly identified 81.7% of the neuraminidase type from a series of human A(H1N1), A(H1N2) and A(H3N2) viruses. This result could be improved to detect the neuraminidase subtype of almost all human influenza A viruses from a large panel of viruses isolated from 2000 to 2005, if the fetuin pre-coating was removed and the viruses were coated directly onto wells. This method is simple, rapid and can be used to screen large numbers of currently circulating human influenza A viruses for their neurraminidase subtype and is a good alternative to RT-PCR.

Evidence synthesis and decision modelling to support complex decisions: stockpiling neuraminidase inhibitors for pandemic influenza usage [version 2; referees: 2 approved

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Samuel I. Watson

2017-03-01

Full Text Available Objectives: The stockpiling of neuraminidase inhibitor (NAI antivirals as a defence against pandemic influenza is a significant public health policy decision that must be made despite a lack of conclusive evidence from randomised controlled trials regarding the effectiveness of NAIs on important clinical end points such as mortality. The objective of this study was to determine whether NAIs should be stockpiled for treatment of pandemic influenza on the basis of current evidence. Methods: A decision model for stockpiling was designed. Data on previous pandemic influenza epidemiology was combined with data on the effectiveness of NAIs in reducing mortality obtained from a recent individual participant meta-analysis using observational data. Evidence synthesis techniques and a bias modelling method for observational data were used to incorporate the evidence into the model. The stockpiling decision was modelled for adults (≥16 years old and the United Kingdom was used as an example. The main outcome was the expected net benefits of stockpiling in monetary terms. Health benefits were estimated from deaths averted through stockpiling. Results: After adjusting for biases in the estimated effectiveness of NAIs, the expected net benefit of stockpiling in the baseline analysis was £444 million, assuming a willingness to pay of £20,000/QALY ($31,000/QALY. The decision would therefore be to stockpile NAIs. There was a greater probability that the stockpile would not be utilised than utilised. However, the rare but catastrophic losses from a severe pandemic justified the decision to stockpile. Conclusions: Taking into account the available epidemiological data and evidence of effectiveness of NAIs in reducing mortality, including potential biases, a decision maker should stockpile anti-influenza medication in keeping with the postulated decision rule.

Neuraminidase-1 contributes significantly to the degradation of neuronal B-series gangliosides but not to the bypass of the catabolic block in Tay–Sachs mouse models

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Z.K. Timur

2015-09-01

Full Text Available Tay–Sachs disease is a severe lysosomal storage disorder caused by mutations in the HEXA gene coding for α subunit of lysosomal β-Hexosaminidase A enzyme, which converts GM2 to GM3 ganglioside. HexA−/− mice, depleted of the β-Hexosaminidase A iso-enzyme, remain asymptomatic up to 1 year of age because of a metabolic bypass by neuraminidase(s. These enzymes remove a sialic acid residue converting GM2 to GA2, which is further degraded by the still intact β-Hexosaminidase B iso-enzyme into lactosylceramide. A previously identified ganglioside metabolizing neuraminidase, Neu4, is abundantly expressed in the mouse brain and has activity against gangliosides like GM2 in vitro. Neu4−/− mice showed increased GD1a and decreased GM1 ganglioside in the brain suggesting the importance of the Neu4 in ganglioside catabolism. Mice with targeted disruption of both HexA and Neu4 genes showed accumulating GM2 ganglioside and epileptic seizures with 40% penetrance, indicating that the neuraminidase Neu4 is a modulatory gene, but may not be the only neuraminidase contributing to the metabolic bypass in HexA−/− mice. Therefore, we elucidated the biological role of neuraminidase-1 in ganglioside degradation in mouse. Analysis of HexA−/−Neu1−/− and HexA−/−Neu4−/−Neu1−/− mice models showed significant contribution of neuraminidase-1 on B-series ganglioside degradation in the brain. Therefore, we speculate that other neuraminidase/neuraminidases such as Neu2 and/or Neu3 might be also involved in the ganglioside degradation pathway in HexA−/− mice.

A new method for tritium labelling of neuraminidase from Vibrio cholerae

International Nuclear Information System (INIS)

Keune, D.

1981-01-01

This research work related to the radioactive labelling with tritium of the enzyme neuraminidase from Vibrio cholerae by an easily handled method. The reactive compound N-propionyloxysuccinimide, the ester of propionic acid and N-hydroxysuccinimide, offered a suitable labelling reagent. For comparison purposes an already known method of labelling neuraminidase with tritium by the oxidation of hydroxyl groups of the hydrocarbon chain of the enzymal protein and subsequent reduction of the aldehyde groups formed with tritiated sodium borhydride, was also carried out. The advantages and disadvantages of both methods are described in detail, in particular with regard to yields of radioactivity and the influence on enzyme activity. The fact that only 1 mg enzymal protein was available for each modification of the enzyme molecule posed particular problems and, as a consequence, extensive preliminary experiments had to be carried with another protein (beef serum album) in the same concentration range. (orig./MG) [de

Exploring the mechanism of zanamivir resistance in a neuraminidase mutant: a molecular dynamics study.

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Nanyu Han

Full Text Available It is critical to understand the molecular basis of the drug resistance of influenza viruses to efficiently treat this infectious disease. Recently, H1N1 strains of influenza A carrying a mutation of Q136K in neuraminidase were found. The new strain showed a strong Zanamivir neutralization effect. In this study, normal molecular dynamics simulations and metadynamics simulations were employed to explore the mechanism of Zanamivir resistance. The wild-type neuraminidase contained a 3(10 helix before the 150 loop, and there was interaction between the 150 and 430 loops. However, the helix and the interaction between the two loops were disturbed in the mutant protein due to interaction between K136 and nearby residues. Hydrogen-bond network analysis showed weakened interaction between the Zanamivir drug and E276/D151 on account of the electrostatic interaction between K136 and D151. Metadynamics simulations showed that the free energy landscape was different in the mutant than in the wild-type neuraminidase. Conformation with the global minimum of free energy for the mutant protein was different from the wild-type conformation. While the drug fit completely into the active site of the wild-type neuraminidase, it did not match the active site of the mutant variant. This study indicates that the altered hydrogen-bond network and the deformation of the 150 loop are the key factors in development of Zanamivir resistance. Furthermore, the Q136K mutation has a variable effect on conformation of different N1 variants, with conformation of the 1918 N1 variant being more profoundly affected than that of the other N1 variants studied in this paper. This observation warrants further experimental investigation.

Core-6 fucose and the oligomerization of the 1918 pandemic influenza viral neuraminidase

International Nuclear Information System (INIS)

Wu, Zhengliang L.; Zhou, Hui; Ethen, Cheryl M.; Reinhold, Vernon N.

2016-01-01

The 1918 H1N1 influenza virus was responsible for one of the most deadly pandemics in human history. Yet to date, the structure component responsible for its virulence is still a mystery. In order to search for such a component, the neuraminidase (NA) antigen of the virus was expressed, which led to the discovery of an active form (tetramer) and an inactive form (dimer and monomer) of the protein due to different glycosylation. In this report, the N-glycans from both forms were released and characterized by mass spectrometry. It was found that the glycans from the active form had 26% core-6 fucosylated, while the glycans from the inactive form had 82% core-6 fucosylated. Even more surprisingly, the stalk region of the active form was almost completely devoid of core-6-linked fucose. These findings were further supported by the results obtained from in vitro incorporation of azido fucose and "3H-labeled fucose using core-6 fucosyltransferase, FUT8. In addition, the incorporation of fucose did not change the enzymatic activity of the active form, implying that core-6 fucose is not directly involved in the enzymatic activity. It is postulated that core-6 fucose prohibits the oligomerization and subsequent activation of the enzyme. - Graphical abstract: Proposed mechanism for how core-fucose prohibits the tetramerization of the 1918 pandemic viral neuraminidase. Only the cross section of the stalk region with two N-linked glycans are depicted for clarity. (A) Carbohydrate–carbohydrate interaction on non-fucosylated monomer allows tetramerization. (B) Core-fucosylation disrupts the interaction and prevents the tetramerization. - Highlights: • Expressed 1918 pandemic influenza viral neuraminidase has inactive and active forms. • The inactive form contains high level of core-6 fucose, while the active form lacks such modification. • Core fucose could interfere the oligomerization of the neuraminidase and thus its activation. • This discovery may explain why

Core-6 fucose and the oligomerization of the 1918 pandemic influenza viral neuraminidase

Energy Technology Data Exchange (ETDEWEB)

Wu, Zhengliang L., E-mail: Leon.wu@bio-techne.com [Bio-Techne Inc., 614 McKinley Place NE, Minneapolis, MN 55413 (United States); Zhou, Hui [Gregg Hall, UNH Glycomics Center, University of New Hampshire (United States); Ethen, Cheryl M. [Bio-Techne Inc., 614 McKinley Place NE, Minneapolis, MN 55413 (United States); Reinhold, Vernon N., E-mail: Vernon.Reinhold@unh.edu [Gregg Hall, UNH Glycomics Center, University of New Hampshire (United States)

2016-04-29

The 1918 H1N1 influenza virus was responsible for one of the most deadly pandemics in human history. Yet to date, the structure component responsible for its virulence is still a mystery. In order to search for such a component, the neuraminidase (NA) antigen of the virus was expressed, which led to the discovery of an active form (tetramer) and an inactive form (dimer and monomer) of the protein due to different glycosylation. In this report, the N-glycans from both forms were released and characterized by mass spectrometry. It was found that the glycans from the active form had 26% core-6 fucosylated, while the glycans from the inactive form had 82% core-6 fucosylated. Even more surprisingly, the stalk region of the active form was almost completely devoid of core-6-linked fucose. These findings were further supported by the results obtained from in vitro incorporation of azido fucose and {sup 3}H-labeled fucose using core-6 fucosyltransferase, FUT8. In addition, the incorporation of fucose did not change the enzymatic activity of the active form, implying that core-6 fucose is not directly involved in the enzymatic activity. It is postulated that core-6 fucose prohibits the oligomerization and subsequent activation of the enzyme. - Graphical abstract: Proposed mechanism for how core-fucose prohibits the tetramerization of the 1918 pandemic viral neuraminidase. Only the cross section of the stalk region with two N-linked glycans are depicted for clarity. (A) Carbohydrate–carbohydrate interaction on non-fucosylated monomer allows tetramerization. (B) Core-fucosylation disrupts the interaction and prevents the tetramerization. - Highlights: • Expressed 1918 pandemic influenza viral neuraminidase has inactive and active forms. • The inactive form contains high level of core-6 fucose, while the active form lacks such modification. • Core fucose could interfere the oligomerization of the neuraminidase and thus its activation. • This discovery may explain

Could a deletion in neuraminidase stalk strengthen human tropism of the novel avian influenza virus H7N9 in China, 2013?

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Chen, Liang; Zhu, Feng; Xiong, Chenglong; Zhang, Zhijie; Jiang, Lufang; Chen, Yue; Zhao, Genming; Jiang, Qingwu

2015-01-20

Objective. A novel avian influenza A virus (AIV) H7N9 subtype which emerged in China in 2013 caused worldwide concern. Deletion of amino-acids 69 to 73 in the neuraminidase stalk was its most notable characteristic. This study is aimed to discuss the tropism and virulence effects of this deletion. Neuraminidase gene sequences of N9 subtype were collected from NCBI and GISAID. MEGA6.0, Stata12.0, and UCSF Chimera were employed for sequence aligning, significance testing, and protein tertiary structure homology modeling. A total of 736 sequences were obtained; there were 81 human isolates of the novel AIV H7N9, of which 79 had the deletion. Among all the 654 avian origin sequences, only 43 had the deletion (p deletion obviously changed the spatial direction of neuraminidase. The deletion in neuraminidase stalk could have strengthened human tropism of the novel AIV H7N9, as well as its virulence.

Influenza A H5N1 clade 2.3.4 virus with a different antiviral susceptibility profile replaced clade 1 virus in humans in northern Vietnam.

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Mai T Q Le

2008-10-01

Full Text Available Prior to 2007, highly pathogenic avian influenza (HPAI H5N1 viruses isolated from poultry and humans in Vietnam were consistently reported to be clade 1 viruses, susceptible to oseltamivir but resistant to amantadine. Here we describe the re-emergence of human HPAI H5N1 virus infections in Vietnam in 2007 and the characteristics of the isolated viruses.Respiratory specimens from patients suspected to be infected with avian influenza in 2007 were screened by influenza and H5 subtype specific polymerase chain reaction. Isolated H5N1 strains were further characterized by genome sequencing and drug susceptibility testing. Eleven poultry outbreak isolates from 2007 were included in the sequence analysis. Eight patients, all of them from northern Vietnam, were diagnosed with H5N1 in 2007 and five of them died. Phylogenetic analysis of H5N1 viruses isolated from humans and poultry in 2007 showed that clade 2.3.4 H5N1 viruses replaced clade 1 viruses in northern Vietnam. Four human H5N1 strains had eight-fold reduced in-vitro susceptibility to oseltamivir as compared to clade 1 viruses. In two poultry isolates the I117V mutation was found in the neuraminidase gene, which is associated with reduced susceptibility to oseltamivir. No mutations in the M2 gene conferring amantadine resistance were found.In 2007, H5N1 clade 2.3.4 viruses replaced clade 1 viruses in northern Vietnam and were susceptible to amantadine but showed reduced susceptibility to oseltamivir. Combination antiviral therapy with oseltamivir and amantadine for human cases in Vietnam is recommended.

Oseltamivir Pharmacokinetics and Clinical Experience in Neonates and Infants during an Outbreak of H1N1 Influenza A Virus Infection in a Neonatal Intensive Care Unit

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Nika, Angela; Tsagris, Vasileios; Kapetanakis, Ioannis; Maltezou, Helena C.; Kafetzis, Dimitris A.; Tsolia, Maria N.

2012-01-01

Detailed oseltamivir pharmacokinetics have yet to be reported in neonates and infants; this group is at high risk of serious influenza-associated complications. Extrapolation of doses from older patients is complicated by rapid organ and drug-metabolizing enzyme maturation. A pharmacokinetic study has been conducted during an influenza A(H1N1) outbreak in a neonatal intensive care unit. Each included patient provided 4 samples for oseltamivir and 4 samples for its active metabolite oseltamivir carboxylate. A population pharmacokinetic model was developed with NONMEM. Allometric weight scaling and maturation functions were added a priori to scale for size and age based on literature values. Nine neonates and infants were recruited. A physiologically parameterized pharmacokinetic model predicted typical day 1 area under the curve (AUC0-12) values of 1,966 and 2,484 μg · h/liter for neonates and infants of ≤37 weeks of postmenstrual age (PMA) and >37 weeks of PMA treated with 1 mg/kg of body weight and 2 mg/kg, respectively. The corresponding steady-state AUC0-12 values were 3,670 and 4,559 μg · h/liter. Premature neonates treated with 1 mg/kg and term babies treated with 2 mg/kg should have average oseltamivir carboxylate concentrations in a range similar to that for adults treated with 75 mg, corresponding to >200-fold above the half-maximal inhibitory concentration (IC50) value for influenza A(H1N1) from the start of therapy. PMID:22564835

Rapid detection of the H275Y oseltamivir resistance mutation in influenza A/H1N1 2009 by single base pair RT-PCR and high-resolution melting.

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Steven Y C Tong

Full Text Available We aimed to design a real-time reverse-transcriptase-PCR (rRT-PCR, high-resolution melting (HRM assay to detect the H275Y mutation that confers oseltamivir resistance in influenza A/H1N1 2009 viruses.A novel strategy of amplifying a single base pair, the relevant SNP at position 823 of the neuraminidase gene, was chosen to maintain specificity of the assay. Wildtype and mutant virus were differentiated when using known reference samples of cell-cultured virus. However, when dilutions of these reference samples were assayed, amplification of non-specific primer-dimer was evident and affected the overall melting temperature (T(m of the amplified products. Due to primer-dimer appearance at >30 cycles we found that if the cycle threshold (C(T for a dilution was >30, the HRM assay did not consistently discriminate mutant from wildtype. Where the C(T was 32.98 would have an H275Y assay C(T>30. Analysis of the TaqMan C(T values for 609 consecutive clinical samples predicted that 207 (34% of the samples would result in an HRM assay C(T>30 and therefore not be amenable to the HRM assay.The use of single base pair PCR and HRM can be useful for specifically interrogating SNPs. When applied to H1N1 09, the constraints this placed on primer design resulted in amplification of primer-dimer products. The impact primer-dimer had on HRM curves was adjusted for by plotting T(m against C(T. Although less sensitive than TaqMan assays, the HRM assay can rapidly, and at low cost, screen samples with moderate viral concentrations.

Antiviral drug profile of human influenza A & B viruses circulating in India: 2004-2011

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V A Potdar

2014-01-01

Full Text Available Background & objectives: Recent influenza antiviral resistance studies in South East Asia, Europe and the United States reveal adamantane and neuraminidase inhibitor (NAIs resistance. This study was undertaken to evaluate antiviral resistance in influenza viruses isolated from various parts of India, during 2004 to 2011. Methods: Influenza viruses were analyzed genetically for known resistance markers by M2 and NA gene sequencing. Influenza A/H1N1 (n=206, A/H3N2 (n=371 viruses for amantadine resistance and A/H1N1 (n=206, A/H3N2 (n=272 and type B (n=326 for oseltamivir resistance were sequenced. Pandemic (H1N1 (n= 493 isolates were tested for H274Y mutation by real time reverse transcription (rRT-PCR. Randomly selected resistant and sensitive influenza A/H1N1 and A/H3N2 viruses were confirmed by phenotypic assay. Results: Serine to asparagine (S3IN mutation was detected in six isolates of 2007-2008.One dual-resistant A/H1N1 was detected for the first time in India with leucine to phenylalanine (L26F mutation in M2 gene and H274Y mutation in NA gene. A/H3N2 viruses showed an increase in resistance to amantadine from 22.5 per cent in 2005 to 100 per cent in 2008 onwards with S3IN mutation. Fifty of the 61 (82% A/H1N1 viruses tested in 2008-2009 were oseltamivir resistant with H274Y mutation, while all A/H3N2, pandemic A/H1N1 and type B isolates remained sensitive. Genetic results were also confirmed by phenotypic analysis of randomly selected 50 resistant A/H1N1 and 40 sensitive A/H3N2 isolates. Interpretation & conclusions: Emergence of influenza viruses resistant to amantadine and oseltamivir in spite of negligible usage of antivirals emphasizes the need for continuous monitoring of antiviral resistance.

Sensitivity of molecular docking to induced fit effects in influenza virus neuraminidase

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Birch, Louise; Murray, Christopher W.; Hartshorn, Michael J.; Tickle, Ian J.; Verdonk, Marcel L.

2002-12-01

Many proteins undergo small side chain or even backbone movements on binding of different ligands into the same protein structure. This is known as induced fit and is potentially problematic for virtual screening of databases against protein targets. In this report we investigate the limits of the rigid protein approximation used by the docking program, GOLD, through cross-docking using protein structures of influenza neuraminidase. Neuraminidase is known to exhibit small but significant induced fit effects on ligand binding. Some neuraminidase crystal structures caused concern due to the bound ligand conformation and GOLD performed poorly on these complexes. A `clean' set, which contained unique, unambiguous complexes, was defined. For this set, the lowest energy structure was correctly docked (i.e. RMSD < 1.5 Å away from the crystal reference structure) in 84% of proteins, and the most promiscuous protein (1mwe) was able to dock all 15 ligands accurately including those that normally required an induced fit movement. This is considerably better than the 70% success rate seen with GOLD against general validation sets. Inclusion of specific water molecules involved in water-mediated hydrogen bonds did not significantly improve the docking performance for ligands that formed water-mediated contacts but it did prevent docking of ligands that displaced these waters. Our data supports the use of a single protein structure for virtual screening with GOLD in some applications involving induced fit effects, although care must be taken to identify the protein structure that performs best against a wide variety of ligands. The performance of GOLD was significantly better than the GOLD implementation of ChemScore and the reasons for this are discussed. Overall, GOLD has shown itself to be an extremely good, robust docking program for this system.

Influence of neuraminidase and X-ray irradiation (2 Gy and 8 Gy) on microvilli and membrane invaginations of Ehrlich ascites tumor cells in monolayer culture

International Nuclear Information System (INIS)

Laudenbach, G.; Baganz, O.; Pfab, R.; Hess, F.; Schachtschabel, D.O.

1987-01-01

A monolayer culture (Eagle basal medium plus 10% of fetal calf serum) of Ehrlich ascites tumor cells was exposed to X-radiation with 2 Gy and 8 Gy and treated with Vibrio cholerae neuraminidase alone or combined with sublethal X-ray irradiation (2 Gy). Pictures of the Ehrlich ascites tumor cells taken with the electron microscope were investigated in order to find out any cell surface modifications due to membrane invaginations and microvilli. The results showed that the rate of microvilli as well as that of membrane invaginations became higher with the increasing X-ray dose (2 Gy; 8 Gy). Following to neuraminidase treatment there was a considerable augmentation of membran invaginations as compared to control cells, whereas the number of microvilli was slightly reduced. As it has been already described before, the influence of neuraminidase produced an increased endocytosis activity and a strengthening of the cytoskeleton. Combined treatment with neuraminidase and sublethal X-radiation (2 Gy) caused a higher rate of membrane invaginations than each method alone; the number of microvilli was slightly increased by combined treatment. The conclusion is drawn that these structure modifications are due to reparation processes induced by radiation on the one hand and to an enzymic action of neuraminidase on the cell surface on the other hand. (orig.) [de

Domain architecture and oligomerization properties of the paramyxovirus PIV 5 hemagglutinin-neuraminidase (HN) protein.

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Yuan, Ping; Leser, George P; Demeler, Borries; Lamb, Robert A; Jardetzky, Theodore S

2008-09-01

The mechanism by which the paramyxovirus hemagglutinin-neuraminidase (HN) protein couples receptor binding to activation of virus entry remains to be fully understood, but the HN stalk is thought to play an important role in the process. We have characterized ectodomain constructs of the parainfluenza virus 5 HN to understand better the underlying architecture and oligomerization properties that may influence HN functions. The PIV 5 neuraminidase (NA) domain is monomeric whereas the ectodomain forms a well-defined tetramer. The HN stalk also forms tetramers and higher order oligomers with high alpha-helical content. Together, the data indicate that the globular NA domains form weak intersubunit interactions at the end of the HN stalk tetramer, while stabilizing the stalk and overall oligomeric state of the ectodomain. Electron microscopy of the HN ectodomain reveals flexible arrangements of the NA and stalk domains, which may be important for understanding how these two HN domains impact virus entry.

Antibody against Microbial Neuraminidases Recognizes Human Sialidase 3 (NEU3: the Neuraminidase/Sialidase Superfamily Revisited

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Chiguang Feng

2017-06-01

Full Text Available Neuraminidases (NAs are critical virulence factors for several microbial pathogens. With a highly conserved catalytic domain, a microbial NA “superfamily” has been proposed. We previously reported that murine polymorphonuclear leukocyte (PMN sialidase activity was important in leukocyte trafficking to inflamed sites and that antibodies to Clostridium perfringens NA recognized a cell surface molecule(s, presumed to be a sialidase of eukaryotic origin on interleukin-8-stimulated human and murine PMNs. These antibodies also inhibited cell sialidase activity both in vitro and, in the latter instance, in vivo. We therefore hypothesized that mammalian sialidases share structural homology and epitopes with microbial NAs. We now report that antibodies to one of the isoforms of C. perfringens NA, as well as anti-influenza virus NA serum, recognize human NEU3 but not NEU1 and that antibodies to C. perfringens NA inhibit NEU3 enzymatic activity. We conclude that the previously described microbial NA superfamily extends to human sialidases. Strategies designed to therapeutically inhibit microbial NA may need to consider potential compromising effects on human sialidases, particularly those expressed in cells of the immune system.

Protection against California 2002 NDV strain afforded by adenovirus vectored vaccine expressing Fusion or Hemagglutination-neuraminidase genes

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Vectored vaccines expressing the combination of the hemagglutinin-neuraminidase (HN) and fusion (F) genes generally have better clinical protection against Newcastle disease virus (NDV) than when either the F and HN genes are expressed alone. Interestingly, the protection induced by F is usually bet...

Using Common Spatial Distributions of Atoms to Relate Functionally Divergent Influenza Virus N10 and N11 Protein Structures to Functionally Characterized Neuraminidase Structures, Toxin Cell Entry Domains, and Non-Influenza Virus Cell Entry Domains

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Weininger, Arthur; Weininger, Susan

2015-01-01

The ability to identify the functional correlates of structural and sequence variation in proteins is a critical capability. We related structures of influenza A N10 and N11 proteins that have no established function to structures of proteins with known function by identifying spatially conserved atoms. We identified atoms with common distributed spatial occupancy in PDB structures of N10 protein, N11 protein, an influenza A neuraminidase, an influenza B neuraminidase, and a bacterial neuraminidase. By superposing these spatially conserved atoms, we aligned the structures and associated molecules. We report spatially and sequence invariant residues in the aligned structures. Spatially invariant residues in the N6 and influenza B neuraminidase active sites were found in previously unidentified spatially equivalent sites in the N10 and N11 proteins. We found the corresponding secondary and tertiary structures of the aligned proteins to be largely identical despite significant sequence divergence. We found structural precedent in known non-neuraminidase structures for residues exhibiting structural and sequence divergence in the aligned structures. In N10 protein, we identified staphylococcal enterotoxin I-like domains. In N11 protein, we identified hepatitis E E2S-like domains, SARS spike protein-like domains, and toxin components shared by alpha-bungarotoxin, staphylococcal enterotoxin I, anthrax lethal factor, clostridium botulinum neurotoxin, and clostridium tetanus toxin. The presence of active site components common to the N6, influenza B, and S. pneumoniae neuraminidases in the N10 and N11 proteins, combined with the absence of apparent neuraminidase function, suggests that the role of neuraminidases in H17N10 and H18N11 emerging influenza A viruses may have changed. The presentation of E2S-like, SARS spike protein-like, or toxin-like domains by the N10 and N11 proteins in these emerging viruses may indicate that H17N10 and H18N11 sialidase-facilitated cell

Microscale Measurements of Michaelis–Menten Constants of Neuraminidase with Nanogel Capillary Electrophoresis for the Determination of the Sialic Acid Linkage

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2016-01-01

Phospholipid nanogels enhance the stability and performance of the exoglycosidase enzyme neuraminidase and are used to create a fixed zone of enzyme within a capillary. With nanogels, there is no need to covalently immobilize the enzyme, as it is physically constrained. This enables rapid quantification of Michaelis–Menten constants (KM) for different substrates and ultimately provides a means to quantify the linkage (i.e., 2-3 versus 2-6) of sialic acids. The fixed zone of enzyme is inexpensive and easily positioned in the capillary to support electrophoresis mediated microanalysis using neuraminidase to analyze sialic acid linkages. To circumvent the limitations of diffusion during static incubation, the incubation period is reproducibly achieved by varying the number of forward and reverse passes the substrate makes through the stationary fixed zone using in-capillary electrophoretic mixing. A KM value of 3.3 ± 0.8 mM (Vmax, 2100 ± 200 μM/min) was obtained for 3′-sialyllactose labeled with 2-aminobenzoic acid using neuraminidase from Clostridium perfringens that cleaves sialic acid monomers with an α2-3,6,8,9 linkage, which is similar to values reported in the literature that required benchtop analyses. The enzyme cleaves the 2-3 linkage faster than the 2-6, and a KM of 2 ± 1 mM (Vmax, 400 ± 100 μM/min) was obtained for the 6′-sialyllactose substrate. An alternative neuraminidase selective for 2-3 sialic acid linkages generated a KM value of 3 ± 2 mM (Vmax, 900 ± 300 μM/min) for 3′-sialyllactose. With a knowledge of Vmax, the method was applied to a mixture of 2-3 and 2-6 sialyllactose as well as 2-3 and 2-6 sialylated triantennary glycan. Nanogel electrophoresis is an inexpensive, rapid, and simple alternative to current technologies used to distinguish the composition of 3′ and 6′ sialic acid linkages. PMID:27936604

Microscale Measurements of Michaelis-Menten Constants of Neuraminidase with Nanogel Capillary Electrophoresis for the Determination of the Sialic Acid Linkage.

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Gattu, Srikanth; Crihfield, Cassandra L; Holland, Lisa A

2017-01-03

Phospholipid nanogels enhance the stability and performance of the exoglycosidase enzyme neuraminidase and are used to create a fixed zone of enzyme within a capillary. With nanogels, there is no need to covalently immobilize the enzyme, as it is physically constrained. This enables rapid quantification of Michaelis-Menten constants (K M ) for different substrates and ultimately provides a means to quantify the linkage (i.e., 2-3 versus 2-6) of sialic acids. The fixed zone of enzyme is inexpensive and easily positioned in the capillary to support electrophoresis mediated microanalysis using neuraminidase to analyze sialic acid linkages. To circumvent the limitations of diffusion during static incubation, the incubation period is reproducibly achieved by varying the number of forward and reverse passes the substrate makes through the stationary fixed zone using in-capillary electrophoretic mixing. A K M value of 3.3 ± 0.8 mM (V max , 2100 ± 200 μM/min) was obtained for 3'-sialyllactose labeled with 2-aminobenzoic acid using neuraminidase from Clostridium perfringens that cleaves sialic acid monomers with an α2-3,6,8,9 linkage, which is similar to values reported in the literature that required benchtop analyses. The enzyme cleaves the 2-3 linkage faster than the 2-6, and a K M of 2 ± 1 mM (V max , 400 ± 100 μM/min) was obtained for the 6'-sialyllactose substrate. An alternative neuraminidase selective for 2-3 sialic acid linkages generated a K M value of 3 ± 2 mM (V max , 900 ± 300 μM/min) for 3'-sialyllactose. With a knowledge of V max , the method was applied to a mixture of 2-3 and 2-6 sialyllactose as well as 2-3 and 2-6 sialylated triantennary glycan. Nanogel electrophoresis is an inexpensive, rapid, and simple alternative to current technologies used to distinguish the composition of 3' and 6' sialic acid linkages.

Plasticity of 150-loop in influenza neuraminidase explored by Hamiltonian replica exchange molecular dynamics simulations.

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Nanyu Han

Full Text Available Neuraminidase (NA of influenza is a key target for antiviral inhibitors, and the 150-cavity in group-1 NA provides new insight in treating this disease. However, NA of 2009 pandemic influenza (09N1 was found lacking this cavity in a crystal structure. To address the issue of flexibility of the 150-loop, Hamiltonian replica exchange molecular dynamics simulations were performed on different groups of NAs. Free energy landscape calculated based on the volume of 150-cavity indicates that 09N1 prefers open forms of 150-loop. The turn A (residues 147-150 of the 150-loop is discovered as the most dynamical motif which induces the inter-conversion of this loop among different conformations. In the turn A, the backbone dynamic of residue 149 is highly related with the shape of 150-loop, thus can function as a marker for the conformation of 150-loop. As a contrast, the closed conformation of 150-loop is more energetically favorable in N2, one of group-2 NAs. The D147-H150 salt bridge is found having no correlation with the conformation of 150-loop. Instead the intimate salt bridge interaction between the 150 and 430 loops in N2 variant contributes the stabilizing factor for the closed form of 150-loop. The clustering analysis elaborates the structural plasticity of the loop. This enhanced sampling simulation provides more information in further structural-based drug discovery on influenza virus.

Immunotherapy with neuraminidase-treated tumor cells after radiotherapy

International Nuclear Information System (INIS)

Song, C.W.; Levitt, S.H.

1975-01-01

The effect of active immunotherapy with Vibrio cholerae neuraminidase-treated syngeneic tumor cells (VCN-cells) following radiotherapy has been studied with 3-methylcholanthrene-induced fibrosarcoma, M-79, transplanted to the thigh of C3H/HeJ mice. When the tumors reached 4 to 8 mm in diameter, various treatments were started. X-irradiation with 2000 rad in a single dose induced a complete regression of 24 out of 103 tumors (23.3 percent). The inoculation of 1 x 10 6 of VCN-cells to the tumor-bearing animals, every other day for a total of three doses, caused a complete regression of 6 out of 57 tumors (10.5 percent). Treatments of animals with the immunotherapy starting 1 day after X-irradiation of tumors with 2000 rad resulted in a complete regression of 22 out of 58 tumors (37.9 percent). The median survival time of animals that received combined radiotherapy and immunotherapy was longer than that observed after either treatment alone

Contribution of murine innate serum inhibitors toward interference within influenza virus immune assays.

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Cwach, Kevin T; Sandbulte, Heather R; Klonoski, Joshua M; Huber, Victor C

2012-03-01

Prior to detection of an antibody response toward influenza viruses using the hemagglutination inhibition assay (HAI), sera are routinely treated to inactivate innate inhibitors using both heat inactivation (56°C) and recombinant neuraminidase [receptor-destroying enzyme (RDE)]. We revisited the contributions of innate serum inhibitors toward interference with influenza viruses in immune assays, using murine sera, with emphasis on the interactions with influenza A viruses of the H3N2 subtype. We used individual serum treatments: 56°C alone, RDE alone, or RDE + 56°C, to treat sera prior to evaluation within HAI, microneutralization, and macrophage uptake assays. Our data demonstrate that inhibitors present within untreated murine sera interfere with the HAI assay in a manner that is different from that seen for the microneutralization assay. Specifically, the γ class inhibitor α(2) -Macroglobulin (A2-M) can inhibit H3N2 viruses within the HAI assay, but not in the microneutralization assay. Based on these findings, we used a macrophage uptake assay to demonstrate that these inhibitors can increase uptake by macrophages when the influenza viruses express an HA from a 1968 H3N2 virus isolate, but not a 1997 H3N2 isolate. The practice of treating sera to inactivate innate inhibitors of influenza viruses prior to evaluation within immune assays has allowed us to effectively detect influenza virus-specific antibodies for decades. However, this practice has yielded an under-appreciation for the contribution of innate serum inhibitors toward host immune responses against these viruses, including contributions toward neutralization and macrophage uptake. © 2011 Blackwell Publishing Ltd.

An influenza A virus (H7N9) anti-neuraminidase monoclonal antibody with prophylactic and therapeutic activity in vivo

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Wilson, Jason R.; Guo, Zhu; Reber, Adrian; Kamal, Ram P.; Music, Nedzad; Gansebom, Shane; Bai, Yaohui; Levine, Min; Carney, Paul; Tzeng, Wen-Pin; Stevens, James; York, Ian A.

2017-01-01

Zoonotic A(H7N9) avian influenza viruses emerged in China in 2013 and continue to be a threat to human public health, having infected over 800 individuals with a mortality rate approaching 40%. Treatment options for people infected with A(H7N9) include the use of neuraminidase (NA) inhibitors. However, like other influenza viruses, A(H7N9) can become resistant to these drugs. The use of monoclonal antibodies is a rapidly developing strategy for controlling influenza virus infection. Here we generated a murine monoclonal antibody (3c10-3) directed against the NA of A(H7N9) and show that prophylactic systemic administration of 3c10-3 fully protected mice from lethal challenge with wild-type A/Anhui/1/2013 (H7N9). Further, post-infection treatment with a single systemic dose of 3c10-3 at either 24, 48 or 72 h post A(H7N9) challenge resulted in both dose- and time-dependent protection of up to 100% of mice, demonstrating therapeutic potential for 3c10-3. Epitope mapping revealed that 3c10-3 binds near the enzyme active site of NA, and functional characterization showed that 3c10-3 inhibits the enzyme activity of NA and restricts the cell-to-cell spread of the virus in cultured cells. Affinity analysis also revealed that 3c10-3 binds equally well to recombinant NA of wild-type A/Anhui/1/2013 and to a variant NA carrying a R289K mutation known to infer NAI resistance. These results suggest that 3c10-3 has the potential to be used as a therapeutic to treat A(H7N9) infections either as an alternative to, or in combination with, current NA antiviral inhibitors. PMID:27713074

New low-viscosity overlay medium for viral plaque assays

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Garten Wolfgang

2006-08-01

Full Text Available Abstract Background Plaque assays in cell culture monolayers under solid or semisolid overlay media are commonly used for quantification of viruses and antiviral substances. To overcome the pitfalls of known overlays, we tested suspensions of microcrystalline cellulose Avicel RC/CL™ as overlay media in the plaque and plaque-inhibition assay of influenza viruses. Results Significantly larger plaques were formed under Avicel-containing media, as compared to agar and methylcellulose (MC overlay media. The plaque size increased with decreasing Avicel concentration, but even very diluted Avicel overlays (0.3% ensured formation of localized plaques. Due to their low viscosity, Avicel overlays were easier to use than methylcellulose overlays, especially in the 96-well culture plates. Furthermore, Avicel overlay could be applied without prior removal of the virus inoculum thus facilitating the assay and reducing chances of cross-contamination. Using neuraminidase inhibitor oseltamivir carboxylate, we demonstrated applicability of the Avicel-based plaque reduction assay for testing of antiviral substances. Conclusion Plaque assay under Avicel-containing overlay media is easier, faster and more sensitive than assays under agar- and methylcellulose overlays. The assay can be readily performed in a 96-well plate format and seems particularly suitable for high-throughput virus titrations, serological studies and experiments on viral drug sensitivity. It may also facilitate work with highly pathogenic agents performed under hampered conditions of bio-safety labs.

The Tamiflu fiasco and lessons learnt.

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Gupta, Yogendra Kumar; Meenu, Meenakshi; Mohan, Prafull

2015-01-01

Oseltamivir (Tamiflu), a neuraminidase inhibitor, was approved for seasonal flu by US Food and Drug Administration in 1999. A number of randomized controlled trials, systematic reviews, and meta-analysis emphasized a favorable efficacy and safety profile. Majority of them were funded by Roche, which also first marketed and promoted this drug. In 2005 and 2009, the looming fear of pandemic flu led to recommendation by prominent regulatory bodies such as World Health Organization (WHO), Centers for Disease Control and Prevention, European Medicines Agency and others for its use in treatment and prophylaxis of influenza, and it's stockpiling as a measure to tide over the crisis. Serious Adverse Events, especially neuropsychiatric events associated with Tamiflu started getting reported leading to a cascade of questions on clinical utility of this drug. A recent Cochrane review and related articles have questioned the risk-benefit ratio of the drug, besides raising doubts about the regulatory decision of approving it. The recommendations for stockpiling the said drug as given by various international organizations viz WHO have also been put to scrutiny. Although many reviewers have labeled the Tamiflu saga as a "costly mistake," the episode leaves us with some important lessons. This article takes a comprehensive relook on the subject, and we proceed to suggest some ways and means to avoid a similar situation in the future.

Gestión del riesgo en la transferencia de procesos productivos: Aplicación a la fabricación de comprimidos de oseltamivir en la pandemia de gripe A Risk management in the transfer of manufacturing processes: Application to the manufacturing of oseltamivir tablets in the swine flu pandemic

OpenAIRE

A. Juberías Sánchez; A. Zamanillo Sainz; JI. Cabrera Merino; M. Verón Moros; MªL. Urquía Grande; MªL. Gonzalo Salado

2011-01-01

Introducción: La gestión de riesgos aplicada a la industria farmacéutica, a través de su identificación, valoración y control, es una herramienta útil para garantizar la calidad del medicamento. La declaración por la Organización Mundial de la Salud en el año 2.009, de la pandemia provocada por el virus de la influenza H1N1, origina la necesidad de transformar en medicamento parte de las reservas estratégicas de fosfato de oseltamivir, pertenecientes al Ministerio de Sanidad y Política Social...

Impacts of papain and neuraminidase enzyme treatment on electrohydrodynamics and IgG-mediated agglutination of type A red blood cells.

Science.gov (United States)

Hyono, Atsushi; Gaboriaud, Fabien; Mazda, Toshio; Takata, Youichi; Ohshima, Hiroyuki; Duval, Jérôme F L

2009-09-15

The stability of native and enzyme-treated human red blood cells of type A (Rh D positive) against agglutination is investigated under conditions where it is mediated by immunoglobuline G (IgG) anti-D antibody binding. The propensity of cells to agglutinate is related to their interphasic (electrokinetic) properties. These properties significantly depend on the concentration of proteolytic papain enzyme and protease-free neuraminidase enzyme that the cells are exposed to. The analysis is based on the interpretation of electrophoretic data of cells by means of the numerical theory for the electrokinetics of soft (bio)particles. A significant reduction of the hydrodynamic permeability of the external soft glycoprotein layer of the cells is reported under the action of papain. This reflects a significant decrease in soft surface layer thickness and a loss in cell surface integrity/rigidity, as confirmed by nanomechanical AFM analysis. Neuraminidase action leads to an important decrease in the interphase charge density by removing sialic acids from the cell soft surface layer. This is accompanied by hydrodynamic softness modulations less significant than those observed for papain-treated cells. On the basis of these electrohydrodynamic characteristics, the overall interaction potential profiles between two native cells and two enzyme-treated cells are derived as a function of the soft surface layer thickness in the Debye-Hückel limit that is valid for cell suspensions under physiological conditions (approximately 0.16 M). The thermodynamic computation of cell suspension stability against IgG-mediated agglutination then reveals that a decrease in the cell surface layer thickness is more favorable than a decrease in interphase charge density for inducing agglutination. This is experimentally confirmed by agglutination data collected for papain- and neuraminidase-treated cells.

Genetic characterization of the influenza A pandemic (H1N1 2009 virus isolates from India.

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Varsha A Potdar

Full Text Available BACKGROUND: The Influenza A pandemic H1N1 2009 (H1N1pdm virus appeared in India in May 2009 and thereafter outbreaks with considerable morbidity and mortality have been reported from many parts of the country. Continuous monitoring of the genetic makeup of the virus is essential to understand its evolution within the country in relation to global diversification and to track the mutations that may affect the behavior of the virus. METHODS: H1N1pdm viruses were isolated from both recovered and fatal cases representing major cities and sequenced. Phylogenetic analyses of six concatenated whole genomes and the hemagglutinin (HA gene of seven more isolates from May-September 2009 was performed with reference to 685 whole genomes of global isolates available as of November 24, 2009. Molecular characterization of all the 8 segments was carried out for known pathogenic markers. RESULTS: The first isolate of May 2009 belonged to clade 5. Although clade 7 was the dominant H1N1pdm lineage in India, both clades 6 and 7 were found to be co-circulating. The neuraminidase of all the Indian isolates possessed H275, the marker for sensitivity to the neuraminidase inhibitor Oseltamivir. Some of the mutations in HA are at or in the vicinity of antigenic sites and may therefore be of possible antigenic significance. Among these a D222G mutation in the HA receptor binding domain was found in two of the eight Indian isolates obtained from fatal cases. CONCLUSIONS: The majority of the 13 Indian isolates grouped in the globally most widely circulating H1N1pdm clade 7. Further, correlations of the mutations specific to clade 7 Indian isolates to viral fitness and adaptability in the country remains to be understood. The D222G mutation in HA from isolates of fatal cases needs to be studied for pathogenicity.

Saccharomyces boulardii expresses neuraminidase activity selective for α2,3-linked sialic acid that decreases Helicobacter pylori adhesion to host cells.

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Sakarya, Serhan; Gunay, Necati

2014-10-01

Helicobacter pylori is a major causative agent of gastritis and peptic ulcer disease and is an established risk factor for gastric malignancy. Antibiotic combination therapy can eradicate H. pylori. As these same regimens can evoke adverse effects and resistance, new alternative therapies or adjunctive treatments are needed. A probiotic approach may provide a novel strategy for H. pylori treatment. In the current study, two probiotic bacteria, Lactobacillus acidophilus and Lactobacillus reuteri, and a probiotic yeast, Saccharomyces boulardii, were evaluated for their ability to influence H. pylori viability, adherence to gastric and duodenal cells, as well as the effect of S. boulardii on cell surface expression of sialic acid. Our results indicate that S. boulardii contains neuraminidase activity selective for α(2-3)-linked sialic acid. This neuraminidase activity removes surface α(2-3)-linked sialic acid, the ligand for the sialic acid-binding H. pylori adhesin, which in turn, inhibits H. pylori adherence to duodenal epithelial cells. © 2014 APMIS. Published by John Wiley & Sons Ltd.

Quantification of peramivir in dog plasma by liquid chromatography/tandem mass spectrometry employing precolumn derivatization.

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Li, Xin; Li, Ying; Wang, Juan; Wang, Lili; Zhong, Wu; Ruan, Jinxiu; Zhang, Zhenqing

2014-01-01

Peramivir is a novel influenza neuraminidase inhibitor used for anti-influenza. In this article, a novel method was developed to determine peramivir in dog plasma using a derivatization treatment step to increase the retention time and enhance the signal intensity. The sample preparation consisted of a protein precipitation extraction followed by derivatization with 10M hydrochloric acid-methanol (10:90, v/v) and determined by liquid chromatography coupled with tandem mass spectrometry. The selected reaction monitoring mode of the positive ion was performed and the precursor to the product ion transitions of m/z 343→284 and m/z 299→152 were used to measure the derivative of peramivir and Ro 64-0802 (internal standard, an active metabolite of oseltamivir). The chromatographic separation was achieved using a ZORBAX RX-C8 (2.0mm×150mm×5μm) analytical column with an isocratic mobile phase composed of acetonitrile-water-formic acid (30:70:0.1, v/v/v, 0.2mL/min). The method was linear over a concentration range of 0.25-250ng/mL. The average intra-day/inter-day precision values were 4.04-8.17% and 3.02-7.08%, respectively, while the average accuracy value was 93.99-106.48%. This method has been successfully applied to the preclinical dog research of peramivir following intragastric administration. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of proteolytic enzymes and neuraminidase on the I and i erythrocyte antigen sites

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Doinel, C.; Ropars, C.; Salmon, C.

1978-01-01

Homogeneous cold agglutinins, purified and labelled with 125 I, have been used in a study of the effects of neuraminidase and proteolytic enzymes on the I and i reactivities of human adult erythrocytes. Measurements were made of antigen site numbers, equilibrium constants and thermodynamic parameters. There was enhanced reactivity after enzyme treatment as well as after the release of N-acetylneuraminic acid. Steric factors were shown to be of primary importance in the accessibility of the I and i antigenic determinant. After enzyme treatment, the antigenic structures became more homogeneous in their reaction with antibodies. The heterogeneity of binding constants observed with antigenic determinants of non-treated erythrocytes is probably due to the wide range of spatial distribution of these receptors within the membrane. (author)

Isolation and characterization of highly pathogenic avian influenza virus subtype H5N1 from donkeys

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2010-01-01

Background The highly pathogenic H5N1 is a major avian pathogen that crosses species barriers and seriously affects humans as well as some mammals. It mutates in an intensified manner and is considered a potential candidate for the possible next pandemic with all the catastrophic consequences. Methods Nasal swabs were collected from donkeys suffered from respiratory distress. The virus was isolated from the pooled nasal swabs in specific pathogen free embryonated chicken eggs (SPF-ECE). Reverse transcriptase polymerase chain reaction (RT-PCR) and sequencing of both haemagglutingin and neuraminidase were performed. H5 seroconversion was screened using haemagglutination inhibition (HI) assay on 105 donkey serum samples. Results We demonstrated that H5N1 jumped from poultry to another mammalian host; donkeys. Phylogenetic analysis showed that the virus clustered within the lineage of H5N1 from Egypt, closely related to 2009 isolates. It harboured few genetic changes compared to the closely related viruses from avian and humans. The neuraminidase lacks oseltamivir resistant mutations. Interestingly, HI screening for antibodies to H5 haemagglutinins in donkeys revealed high exposure rate. Conclusions These findings extend the host range of the H5N1 influenza virus, possess implications for influenza virus epidemiology and highlight the need for the systematic surveillance of H5N1 in animals in the vicinity of backyard poultry units especially in endemic areas. PMID:20398268

An influenza A virus (H7N9) anti-neuraminidase monoclonal antibody protects mice from morbidity without interfering with the development of protective immunity to subsequent homologous challenge.

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Wilson, Jason R; Belser, Jessica A; DaSilva, Juliana; Guo, Zhu; Sun, Xiangjie; Gansebom, Shane; Bai, Yaohui; Stark, Thomas J; Chang, Jessie; Carney, Paul; Levine, Min Z; Barnes, John; Stevens, James; Maines, Taronna R; Tumpey, Terrence M; York, Ian A

2017-11-01

The emergence of A(H7N9) virus strains with resistance to neuraminidase (NA) inhibitors highlights a critical need to discover new countermeasures for treatment of A(H7N9) virus-infected patients. We previously described an anti-NA mAb (3c10-3) that has prophylactic and therapeutic efficacy in mice lethally challenged with A(H7N9) virus when delivered intraperitoneally (i.p.). Here we show that intrananasal (i.n.) administration of 3c10-3 protects 100% of mice from mortality when treated 24h post-challenge and further characterize the protective efficacy of 3c10-3 using a nonlethal A(H7N9) challenge model. Administration of 3c10-3 i.p. 24h prior to challenge resulted in a significant decrease in viral lung titers and deep sequencing analysis indicated that treatment did not consistently select for viral variants in NA. Furthermore, prophylactic administration of 3c10-3 did not inhibit the development of protective immunity to subsequent homologous virus re-challenge. Taken together, 3c10-3 highlights the potential use of anti-NA mAb to mitigate influenza virus infection. Published by Elsevier Inc.

Molecular Characterizations of Surface Proteins Hemagglutinin and Neuraminidase from Recent H5Nx Avian Influenza Viruses

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Yang, Hua; Carney, Paul J.; Mishin, Vasiliy P.; Guo, Zhu; Chang, Jessie C.; Wentworth, David E.; Gubareva, Larisa V.; Stevens, James; Schultz-Cherry, S.

2016-04-06

During 2014, a subclade 2.3.4.4 highly pathogenic avian influenza (HPAI) A(H5N8) virus caused poultry outbreaks around the world. In late 2014/early 2015, the virus was detected in wild birds in Canada and the United States, and these viruses also gave rise to reassortant progeny, composed of viral RNA segments (vRNAs) from both Eurasian and North American lineages. In particular, viruses were found with N1, N2, and N8 neuraminidase vRNAs, and these are collectively referred to as H5Nx viruses. In the United States, more than 48 million domestic birds have been affected. Here we present a detailed structural and biochemical analysis of the surface antigens of H5N1, H5N2, and H5N8 viruses in addition to those of a recent human H5N6 virus. Our results with recombinant hemagglutinin reveal that these viruses have a strict avian receptor binding preference, while recombinantly expressed neuraminidases are sensitive to FDA-approved and investigational antivirals. Although H5Nx viruses currently pose a low risk to humans, it is important to maintain surveillance of these circulating viruses and to continually assess future changes that may increase their pandemic potential.

IMPORTANCEThe H5Nx viruses emerging in North America, Europe, and Asia pose a great public health concern. Here we report a molecular and structural study of the major surface proteins of several H5Nx influenza viruses. Our results improve the understanding of these new viruses and provide important information on their receptor preferences and susceptibilities to antivirals, which are central to pandemic risk assessment.

Carbasugars: Synthesis and Functions

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Kobayashi, Yoshiyuki

It is well recognized that glycosidase inhibitors are not only tools to elucidate the mechanism of a living system manipulated by glycoconjugates but also potential clinical drugs and insecticides by inducing the failure of glycoconjugates to perform their function. In this chapter, the syntheses and functions of natural glycosidase inhibitors (cyclophelitol , allosamidine , and trehazoilin ), which possess highly oxygenated and functionalized cyclohexanes or cyclopentanes in their structures and are defined as carbasugars , and the structure and activity relationships (SAR) of their derivatives are described. Also, recently much attention has been focused on neuraminidase inhibitors as anti-influenza drugs since relenza , which was derived from sialic acid, and also, tamiflu , which is the artificial carbasugar designed as a transition state analogue in the hydrolysis pathway of substrates by neuraminidase, were launched in the market. Herein, the medicinal chemistry efforts to discover tamiflu and some efficient syntheses applicable to process chemistry are described. Finally, useful synthetic methodologies for carbasugar formation from sugars are also introduced in this chapter.

Kinetic Study of the Alkaline Degradation of Oseltamivir Phosphate and Valacyclovir Hydrochloride using Validated Stability Indicating HPLC

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Ramzia I. Al-Bagary

2014-01-01

Full Text Available Aqueous alkaline degradation was performed for oseltamivir phosphate (OP and valacyclovir hydrochloride (VA. Isocratic stability indicating the use of high-performance liquid chromatography (HPLC was presented for each drug in the presence of its degradation product. The separations were performed using the Nucleosil ODS column and a mobile phase consisting of phosphate buffer (pH = 7, acetonitrile, and methanol 50:25:25 (v/v/v for OP. For VA separation, a Nucleosil CN column using phosphate buffer (pH = 7 and methanol 85:15 (v/v was used as a mobile phase. Ultraviolet detection at 210 nm and 254 nm was used for OP and VA, respectively. The method showed high sensitivity concerning linearity, accuracy, and precision over the range 1-250 μg mL −1 for both drugs. The proposed method was used to determine the drug in its pharmaceutical formulation and to investigate the degradation kinetics of each drug's alkaline-stressed samples. The reactions were found to follow a first-order reaction. The activation energy could also be estimated. International Conference on Harmonisation guidelines were adopted for method validation.

Isolation and characterization of highly pathogenic avian influenza virus subtype H5N1 from donkeys

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Abdel-Ghany Ahmad E

2010-04-01

Full Text Available Abstract Background The highly pathogenic H5N1 is a major avian pathogen that crosses species barriers and seriously affects humans as well as some mammals. It mutates in an intensified manner and is considered a potential candidate for the possible next pandemic with all the catastrophic consequences. Methods Nasal swabs were collected from donkeys suffered from respiratory distress. The virus was isolated from the pooled nasal swabs in specific pathogen free embryonated chicken eggs (SPF-ECE. Reverse transcriptase polymerase chain reaction (RT-PCR and sequencing of both haemagglutingin and neuraminidase were performed. H5 seroconversion was screened using haemagglutination inhibition (HI assay on 105 donkey serum samples. Results We demonstrated that H5N1 jumped from poultry to another mammalian host; donkeys. Phylogenetic analysis showed that the virus clustered within the lineage of H5N1 from Egypt, closely related to 2009 isolates. It harboured few genetic changes compared to the closely related viruses from avian and humans. The neuraminidase lacks oseltamivir resistant mutations. Interestingly, HI screening for antibodies to H5 haemagglutinins in donkeys revealed high exposure rate. Conclusions These findings extend the host range of the H5N1 influenza virus, possess implications for influenza virus epidemiology and highlight the need for the systematic surveillance of H5N1 in animals in the vicinity of backyard poultry units especially in endemic areas.

Anti-influenza drugs: the development of sialidase inhibitors.

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von Itzstein, Mark; Thomson, Robin

2009-01-01

Viruses, particularly those that are harmful to humans, are the 'silent terrorists' of the twenty-first century. Well over four million humans die per annum as a result of viral infections alone. The scourge of influenza virus has plagued mankind throughout the ages. The fact that new viral strains emerge on a regular basis, particularly out of Asia, establishes a continual socio-economic threat to mankind. The arrival of the highly pathogenic avian influenza H5N1 heightened the threat of a potential human pandemic to the point where many countries have put in place 'preparedness plans' to defend against such an outcome. The discovery of the first designer influenza virus sialidase inhibitor and anti-influenza drug Relenza, and subsequently Tamiflu, has now inspired a number of continuing efforts towards the discovery of next generation anti-influenza drugs. Such drugs may act as 'first-line-of-defence' against the spread of influenza infection and buy time for necessary vaccine development particularly in a human pandemic setting. Furthermore, the fact that influenza virus can develop resistance to therapeutics makes these continuing efforts extremely important. An overview of the role of the virus-associated glycoprotein sialidase (neuraminidase) and some of the most recent developments towards the discovery of anti-influenza drugs based on the inhibition of influenza virus sialidase is provided in this chapter.

Development and evaluation of an avian influenza, neuraminidase subtype 1, indirect enzyme-linked immunosorbent assay for poultry using the differentiation of infected from vaccinated animals control strategy.

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Liu, Y; Mundt, E; Mundt, A; Sylte, M; Suarez, D L; Swayne, D E; García, M

2010-03-01

An indirect enzyme-linked immunosorbent assay (ELISA) was developed using baculovirus, purified, recombinant N1 protein from A/chicken/Indonesia/PA7/2003 (H5N1) virus. The N1-ELISA showed high selectivity for detection of N1 antibodies, with no cross-reactivity with other neuraminidase subtypes, and broad reactivity with sera to N1 subtype isolates from North American and Eurasian lineages. Sensitivity of the N1-ELISA to detect N1 antibodies in turkey sera, collected 3 wk after H1N1 vaccination, was comparable to detection of avian influenza antibodies by the commercial, indirect ELISAs ProFLOK AIV Plus ELISA Kit (Synbiotics, Kansas City, MO) and Avian Influenza Virus Antibody Test Kit (IDEXX, Westbrook, ME). However, 6 wk after vaccination, the Synbiotics ELISA kit performed better than the N1-ELISA and the IDEXX ELISA kit. An evaluation was made of the ability of the N1-ELISA to discriminate vaccinated chickens from subsequently challenged chickens. Two experiments were conducted, chickens were vaccinated with inactivated H5N2 and H5N9 viruses and challenged with highly pathogenic H5N1 virus, and chickens were vaccinated with recombinant poxvirus vaccine encoding H7 and challenged with highly pathogenic H7N1 virus. Serum samples were collected at 14 days postchallenge and tested by hemagglutination inhibition (HI), quantitative neuraminidase inhibition (NI), and N1-ELISA. At 2 days postchallenge, oropharyngeal swabs were collected for virus isolation (VI) to confirm infection. The N1-ELISA was in fair agreement with VI and HI results. Although the N1-ELISA showed a lower sensitivity than the NI assay, it was demonstrated that detection of N1 antibodies by ELISA was an effective and rapid assay to identify exposure to the challenge virus in vaccinated chickens. Therefore, N1-ELISA can facilitate a vaccination strategy with differentiation of infected from vaccinated animals using a neuraminidase heterologous approach.

Neuraminidase activity mediates IL-6 production by activated lupus-prone mesangial cells.

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Sundararaj, Kamala; Rodgers, Jessalyn I; Marimuthu, Subathra; Siskind, Leah J; Bruner, Evelyn; Nowling, Tamara K

2018-04-01

The development of nephritis is a leading cause of morbidity and mortality in lupus patients. Although the general pathophysiological progression of lupus nephritis is known, the molecular mediators and mechanisms are incompletely understood. Previously, we demonstrated that the glycosphingolipid (GSL) catabolic pathway is elevated in the kidneys of MRL/lpr lupus mice and human lupus patients with nephritis. Specifically, the activity of neuraminidase (NEU) and expression of Neu1, an enzyme in the GSL catabolic pathway is significantly increased. To better understand the role and mechanisms by which this pathway contributes to the progression of LN, we analyzed the expression and effects of NEU activity on the function of MRL/lpr lupus-prone mesangial cells (MCs). We demonstrate that NEU1 and NEU3 promote IL-6 production in MES13 MCs. Neu1 expression, NEU activity, and IL-6 production are significantly increased in stimulated primary MRL/lpr lupus-prone MCs, and blocking NEU activity inhibits IL-6 production. NEU1 and NEU3 expression overlaps IgG deposits in MCs in vitro and in renal sections from nephritic MRL/lpr mice. Together, our results suggest that NEU activity mediates IL-6 production in lupus-prone MCs possibly through an IgG-receptor complex signaling pathway.

Expression of Insoluble Influenza Neuraminidase Type 1 (NA1 Protein in Tobacco

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Teen Lee Pua

2012-12-01

Full Text Available The avian influenza virus, particularly H5N1 strain, is highly virulent to poultry and mankind. Several expression systems, like yeast, baculovirus and mammalian cells, have been adopted to produce vaccine candidate for this lethal disease. The present research aimed at developing a recombinant vaccine candidate, neuraminidase type 1 (NA1, for the Malaysia isolate of H5N1 in Nicotiana benthamiana. The NA1 gene was fused directly in-frame in cowpea mosaic virus (CPMV-based pEAQ-HT vector with C-terminal polyhistidine-tag incorporated to ease the subsequent purification step. The expression of the NA1 gene in tobacco was confirmed at RNA and protein levels at 6 days post-infiltration (Dpi. From the insoluble fraction of the protein, a recombinant glycosylated NA1 protein with a molecular weight of ~56 kDa was immunogenically detected by a specific anti-NA polyclonal antibody. We report for the first time the insolubility of the plant-made NA1 protein where a native sequence was used for its expression. This study signifies the necessity of the use of optimised sequences for expression work and provides great opportunity for the exploration of plant-manufactured NA1 protein as vaccine candidate.

Streptococcus oralis Neuraminidase Modulates Adherence to Multiple Carbohydrates on Platelets

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Singh, Anirudh K.; Woodiga, Shireen A.; Grau, Margaret A.

2016-01-01

ABSTRACT Adherence to host surfaces is often mediated by bacterial binding to surface carbohydrates. Although it is widely appreciated that some bacterial species express glycosidases, previous studies have not considered whether bacteria bind to multiple carbohydrates within host glycans as they are modified by bacterial glycosidases. Streptococcus oralis is a leading cause of subacute infective endocarditis. Binding to platelets is a critical step in disease; however, the mechanisms utilized by S. oralis remain largely undefined. Studies revealed that S. oralis, like Streptococcus gordonii and Streptococcus sanguinis, binds platelets via terminal sialic acid. However, unlike those organisms, S. oralis produces a neuraminidase, NanA, which cleaves terminal sialic acid. Further studies revealed that following NanA-dependent removal of terminal sialic acid, S. oralis bound exposed β-1,4-linked galactose. Adherence to both these carbohydrates required Fap1, the S. oralis member of the serine-rich repeat protein (SRRP) family of adhesins. Mutation of a conserved residue required for sialic acid binding by other SRRPs significantly reduced platelet binding, supporting the hypothesis that Fap1 binds this carbohydrate. The mechanism by which Fap1 contributes to β-1,4-linked galactose binding remains to be defined; however, binding may occur via additional domains of unknown function within the nonrepeat region, one of which shares some similarity with a carbohydrate binding module. This study is the first demonstration that an SRRP is required to bind β-1,4-linked galactose and the first time that one of these adhesins has been shown to be required for binding of multiple glycan receptors. PMID:27993975

Discovery of dapivirine, a nonnucleoside HIV-1 reverse transcriptase inhibitor, as a broad-spectrum antiviral against both influenza A and B viruses.

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Hu, Yanmei; Zhang, Jiantao; Musharrafieh, Rami Ghassan; Ma, Chunlong; Hau, Raymond; Wang, Jun

2017-09-01

The emergence of multidrug-resistant influenza viruses poses a persistent threat to public health. The current prophylaxis and therapeutic interventions for influenza virus infection have limited efficacy due to the continuous antigenic drift and antigenic shift of influenza viruses. As part of our ongoing effort to develop the next generation of influenza antivirals with broad-spectrum antiviral activity and a high genetic barrier to drug resistance, in this study we report the discovery of dapivirine, an FDA-approved HIV nonnucleoside reverse transcriptase inhibitor, as a broad-spectrum antiviral against multiple strains of influenza A and B viruses with low micromolar efficacy. Mechanistic studies revealed that dapivirine inhibits the nuclear entry of viral ribonucleoproteins at the early stage of viral replication. As a result, viral RNA and protein synthesis were inhibited. Furthermore, dapivirine has a high in vitro genetic barrier to drug resistance, and its antiviral activity is synergistic with oseltamivir carboxylate. In summary, the in vitro antiviral results of dapivirine suggest it is a promising candidate for the development of the next generation of dual influenza and HIV antivirals. Copyright © 2017 Elsevier B.V. All rights reserved.

Streptococcus oralis Neuraminidase Modulates Adherence to Multiple Carbohydrates on Platelets.

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Singh, Anirudh K; Woodiga, Shireen A; Grau, Margaret A; King, Samantha J

2017-03-01

Adherence to host surfaces is often mediated by bacterial binding to surface carbohydrates. Although it is widely appreciated that some bacterial species express glycosidases, previous studies have not considered whether bacteria bind to multiple carbohydrates within host glycans as they are modified by bacterial glycosidases. Streptococcus oralis is a leading cause of subacute infective endocarditis. Binding to platelets is a critical step in disease; however, the mechanisms utilized by S. oralis remain largely undefined. Studies revealed that S. oralis , like Streptococcus gordonii and Streptococcus sanguinis , binds platelets via terminal sialic acid. However, unlike those organisms, S. oralis produces a neuraminidase, NanA, which cleaves terminal sialic acid. Further studies revealed that following NanA-dependent removal of terminal sialic acid, S. oralis bound exposed β-1,4-linked galactose. Adherence to both these carbohydrates required Fap1, the S. oralis member of the serine-rich repeat protein (SRRP) family of adhesins. Mutation of a conserved residue required for sialic acid binding by other SRRPs significantly reduced platelet binding, supporting the hypothesis that Fap1 binds this carbohydrate. The mechanism by which Fap1 contributes to β-1,4-linked galactose binding remains to be defined; however, binding may occur via additional domains of unknown function within the nonrepeat region, one of which shares some similarity with a carbohydrate binding module. This study is the first demonstration that an SRRP is required to bind β-1,4-linked galactose and the first time that one of these adhesins has been shown to be required for binding of multiple glycan receptors. Copyright © 2017 American Society for Microbiology.

Vaccination with Recombinant Parainfluenza Virus 5 Expressing Neuraminidase Protects against Homologous and Heterologous Influenza Virus Challenge.

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Mooney, Alaina J; Gabbard, Jon D; Li, Zhuo; Dlugolenski, Daniel A; Johnson, Scott K; Tripp, Ralph A; He, Biao; Tompkins, S Mark

2017-12-01

Seasonal human influenza virus continues to cause morbidity and mortality annually, and highly pathogenic avian influenza (HPAI) viruses along with other emerging influenza viruses continue to pose pandemic threats. Vaccination is considered the most effective measure for controlling influenza; however, current strategies rely on a precise vaccine match with currently circulating virus strains for efficacy, requiring constant surveillance and regular development of matched vaccines. Current vaccines focus on eliciting specific antibody responses against the hemagglutinin (HA) surface glycoprotein; however, the diversity of HAs across species and antigenic drift of circulating strains enable the evasion of virus-inhibiting antibody responses, resulting in vaccine failure. The neuraminidase (NA) surface glycoprotein, while diverse, has a conserved enzymatic site and presents an appealing target for priming broadly effective antibody responses. Here we show that vaccination with parainfluenza virus 5 (PIV5), a promising live viral vector expressing NA from avian (H5N1) or pandemic (H1N1) influenza virus, elicited NA-specific antibody and T cell responses, which conferred protection against homologous and heterologous influenza virus challenges. Vaccination with PIV5-N1 NA provided cross-protection against challenge with a heterosubtypic (H3N2) virus. Experiments using antibody transfer indicate that antibodies to NA have an important role in protection. These findings indicate that PIV5 expressing NA may be effective as a broadly protective vaccine against seasonal influenza and emerging pandemic threats. IMPORTANCE Seasonal influenza viruses cause considerable morbidity and mortality annually, while emerging viruses pose potential pandemic threats. Currently licensed influenza virus vaccines rely on the antigenic match of hemagglutinin (HA) for vaccine strain selection, and most vaccines rely on HA inhibition titers to determine efficacy, despite the growing

Filament-producing mutants of influenza A/Puerto Rico/8/1934 (H1N1 virus have higher neuraminidase activities than the spherical wild-type.

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Jill Seladi-Schulman

Full Text Available Influenza virus exhibits two morphologies - spherical and filamentous. Strains that have been grown extensively in laboratory substrates are comprised predominantly of spherical virions while clinical or low passage isolates produce a mixture of spheres and filamentous virions of varying lengths. The filamentous morphology can be lost upon continued passage in embryonated chicken eggs, a common laboratory substrate for influenza viruses. The fact that the filamentous morphology is maintained in nature but lost in favor of a spherical morphology in ovo suggests that filaments confer a selective advantage within the infected host that is not necessary for growth in laboratory substrates. Indeed, we have recently shown that filament-producing variant viruses are selected upon passage of the spherical laboratory strain A/Puerto Rico/8/1934 (H1N1 [PR8] in guinea pigs. Toward determining the nature of the selective advantage conferred by filaments, we sought to identify functional differences between spherical and filamentous particles. We compared the wild-type PR8 virus to two previously characterized recombinant PR8 viruses in which single point mutations within M1 confer a filamentous morphology. Our results indicate that these filamentous PR8 mutants have higher neuraminidase activities than the spherical PR8 virus. Conversely, no differences were observed in HAU:PFU or HAU:RNA ratios, binding avidity, sensitivity to immune serum in hemagglutination inhibition assays, or virion stability at elevated temperatures. Based on these results, we propose that the pleomorphic nature of influenza virus particles is important for the optimization of neuraminidase functions in vivo.

Virus-like particles displaying H5, H7, H9 hemagglutinins and N1 neuraminidase elicit protective immunity to heterologous avian influenza viruses in chickens

International Nuclear Information System (INIS)

Pushko, Peter; Tretyakova, Irina; Hidajat, Rachmat; Zsak, Aniko; Chrzastek, Klaudia; Tumpey, Terrence M.; Kapczynski, Darrell R.

2017-01-01

Avian influenza (AI) viruses circulating in wild birds pose a serious threat to public health. Human and veterinary vaccines against AI subtypes are needed. Here we prepared triple-subtype VLPs that co-localized H5, H7 and H9 antigens derived from H5N1, H7N3 and H9N2 viruses. VLPs also contained influenza N1 neuraminidase and retroviral gag protein. The H5/H7/H9/N1/gag VLPs were prepared using baculovirus expression. Biochemical, functional and antigenic characteristics were determined including hemagglutination and neuraminidase enzyme activities. VLPs were further evaluated in a chicken AI challenge model for safety, immunogenicity and protective efficacy against heterologous AI viruses including H5N2, H7N3 and H9N2 subtypes. All vaccinated birds survived challenges with H5N2 and H7N3 highly pathogenic AI (HPAI) viruses, while all controls died. Immune response was also detectable after challenge with low pathogenicity AI (LPAI) H9N2 virus suggesting that H5/H7/H9/N1/gag VLPs represent a promising approach for the development of broadly protective AI vaccine. - Highlights: •VLPs were prepared that co-localized H5, H7 and H9 subtypes in a VLP envelope. •VLPs were characterized including electron microscopy, HA assay and NA enzyme activity. •Experimental VLP vaccine was evaluated in an avian influenza challenge model. •VLPs induced immune responses against heterologous H5, H7 and H9 virus challenges.

Virus-like particles displaying H5, H7, H9 hemagglutinins and N1 neuraminidase elicit protective immunity to heterologous avian influenza viruses in chickens

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Pushko, Peter, E-mail: ppushko@medigen-usa.com [Medigen, Inc., 8420 Gas House Pike, Suite S, Frederick, MD 21701 (United States); Tretyakova, Irina; Hidajat, Rachmat [Medigen, Inc., 8420 Gas House Pike, Suite S, Frederick, MD 21701 (United States); Zsak, Aniko; Chrzastek, Klaudia [USDA SEPRL, 934 College Station Rd, Athens, GA (United States); Tumpey, Terrence M. [Influenza Division, CDC,1600 Clifton Road N.E., Atlanta, GA (United States); Kapczynski, Darrell R. [USDA SEPRL, 934 College Station Rd, Athens, GA (United States)

2017-01-15

Avian influenza (AI) viruses circulating in wild birds pose a serious threat to public health. Human and veterinary vaccines against AI subtypes are needed. Here we prepared triple-subtype VLPs that co-localized H5, H7 and H9 antigens derived from H5N1, H7N3 and H9N2 viruses. VLPs also contained influenza N1 neuraminidase and retroviral gag protein. The H5/H7/H9/N1/gag VLPs were prepared using baculovirus expression. Biochemical, functional and antigenic characteristics were determined including hemagglutination and neuraminidase enzyme activities. VLPs were further evaluated in a chicken AI challenge model for safety, immunogenicity and protective efficacy against heterologous AI viruses including H5N2, H7N3 and H9N2 subtypes. All vaccinated birds survived challenges with H5N2 and H7N3 highly pathogenic AI (HPAI) viruses, while all controls died. Immune response was also detectable after challenge with low pathogenicity AI (LPAI) H9N2 virus suggesting that H5/H7/H9/N1/gag VLPs represent a promising approach for the development of broadly protective AI vaccine. - Highlights: •VLPs were prepared that co-localized H5, H7 and H9 subtypes in a VLP envelope. •VLPs were characterized including electron microscopy, HA assay and NA enzyme activity. •Experimental VLP vaccine was evaluated in an avian influenza challenge model. •VLPs induced immune responses against heterologous H5, H7 and H9 virus challenges.

Synthesis of Pyrazine-1,3-thiazine Hybrid Analogues as Antiviral Agent Against HIV-1, Influenza A (H1N1), Enterovirus 71 (EV71), and Coxsackievirus B3 (CVB3).

Science.gov (United States)

Wu, Hong-Min; Zhou, Kuo; Wu, Tao; Cao, Yin-Guang

2016-09-01

A novel series of pyrazine-1,3-thiazine hybrid conjugates were synthesized in excellent yield. These derivatives were subsequently tested against human immunodeficiency virus (HIV-1); hemagglutinin type 1 and neuraminidase type 1-'influenza' A (H1N1) virus; enterovirus 71 (EV71); and coxsackievirus B3. The effect of these conjugates on the key enzymes responsible for the progression of these viral infections was also illustrated via enzyme-based assay, such as HIV-1 reverse transcriptase (RT) and neuraminidase, where entire tested molecules showed considerable inhibition. Particularly, among the tested derivatives, compound 3k was identified as most promising inhibitor of HIV-1 with 94% of inhibition (IC50 3.26 ± 0.2 μm). Moreover, the compound 3d was found to be the most potent analogue to inhibit the H1N1 virus with IC50 of 5.32 ± 0.4 μm together with inhibition of the neuraminidase enzyme (IC50 11.24 ± 1.1 μm). In regard to inhibitory activity against enterovirus 71 (EV71) and coxsackievirus B3 (CVB3), the tested derivatives showed considerable inhibition of infection. Molecular docking studies were also performed for the most promising inhibitors with their corresponding target protein to exemplify the structural requirement for better inhibitory activity. The results of inhibitory assay showed that designed molecules possess considerable inhibitory activity against the virus tested. © 2016 John Wiley & Sons A/S.

Identification of a novel multiple kinase inhibitor with potent antiviral activity against influenza virus by reducing viral polymerase activity

Energy Technology Data Exchange (ETDEWEB)

Sasaki, Yutaka; Kakisaka, Michinori; Chutiwitoonchai, Nopporn [Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Tajima, Shigeru [Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640 (Japan); Hikono, Hirokazu; Saito, Takehiko [Influenza and Prion Disease Research Center, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856 (Japan); Aida, Yoko, E-mail: aida@riken.jp [Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

2014-07-18

Highlights: • Screening of 50,000 compounds and subsequent lead optimization identified WV970. • WV970 has antiviral effects against influenza A, B and highly pathogenic viral strains. • WV970 inhibits viral genome replication and transcription. • A target database search suggests that WV970 may bind to a number of kinases. • KINOMEscan screening revealed that WV970 has inhibitory effects on 15 kinases. - Abstract: Neuraminidase inhibitors are the only currently available influenza treatment, although resistant viruses to these drugs have already been reported. Thus, new antiviral drugs with novel mechanisms of action are urgently required. In this study, we identified a novel antiviral compound, WV970, through cell-based screening of a 50,000 compound library and subsequent lead optimization. This compound exhibited potent antiviral activity with nanomolar IC{sub 50} values against both influenza A and B viruses but not non-influenza RNA viruses. Time-of-addition and indirect immunofluorescence assays indicated that WV970 acted at an early stage of the influenza life cycle, but likely after nuclear entry of viral ribonucleoprotein (vRNP). Further analyses of viral RNA expression and viral polymerase activity indicated that WV970 inhibited vRNP-mediated viral genome replication and transcription. Finally, structure-based virtual screening and comprehensive human kinome screening were used to demonstrate that WV970 acts as a multiple kinase inhibitor, many of which are associated with influenza virus replication. Collectively, these results strongly suggest that WV970 is a promising anti-influenza drug candidate and that several kinases associated with viral replication are promising drug targets.

Identification of a novel multiple kinase inhibitor with potent antiviral activity against influenza virus by reducing viral polymerase activity

International Nuclear Information System (INIS)

Sasaki, Yutaka; Kakisaka, Michinori; Chutiwitoonchai, Nopporn; Tajima, Shigeru; Hikono, Hirokazu; Saito, Takehiko; Aida, Yoko

2014-01-01

Highlights: • Screening of 50,000 compounds and subsequent lead optimization identified WV970. • WV970 has antiviral effects against influenza A, B and highly pathogenic viral strains. • WV970 inhibits viral genome replication and transcription. • A target database search suggests that WV970 may bind to a number of kinases. • KINOMEscan screening revealed that WV970 has inhibitory effects on 15 kinases. - Abstract: Neuraminidase inhibitors are the only currently available influenza treatment, although resistant viruses to these drugs have already been reported. Thus, new antiviral drugs with novel mechanisms of action are urgently required. In this study, we identified a novel antiviral compound, WV970, through cell-based screening of a 50,000 compound library and subsequent lead optimization. This compound exhibited potent antiviral activity with nanomolar IC 50 values against both influenza A and B viruses but not non-influenza RNA viruses. Time-of-addition and indirect immunofluorescence assays indicated that WV970 acted at an early stage of the influenza life cycle, but likely after nuclear entry of viral ribonucleoprotein (vRNP). Further analyses of viral RNA expression and viral polymerase activity indicated that WV970 inhibited vRNP-mediated viral genome replication and transcription. Finally, structure-based virtual screening and comprehensive human kinome screening were used to demonstrate that WV970 acts as a multiple kinase inhibitor, many of which are associated with influenza virus replication. Collectively, these results strongly suggest that WV970 is a promising anti-influenza drug candidate and that several kinases associated with viral replication are promising drug targets

New Insights into Molecular Organization of Human Neuraminidase-1: Transmembrane Topology and Dimerization Ability

Science.gov (United States)

Maurice, Pascal; Baud, Stéphanie; Bocharova, Olga V.; Bocharov, Eduard V.; Kuznetsov, Andrey S.; Kawecki, Charlotte; Bocquet, Olivier; Romier, Beatrice; Gorisse, Laetitia; Ghirardi, Maxime; Duca, Laurent; Blaise, Sébastien; Martiny, Laurent; Dauchez, Manuel; Efremov, Roman G.; Debelle, Laurent

2016-12-01

Neuraminidase 1 (NEU1) is a lysosomal sialidase catalyzing the removal of terminal sialic acids from sialyloconjugates. A plasma membrane-bound NEU1 modulating a plethora of receptors by desialylation, has been consistently documented from the last ten years. Despite a growing interest of the scientific community to NEU1, its membrane organization is not understood and current structural and biochemical data cannot account for such membrane localization. By combining molecular biology and biochemical analyses with structural biophysics and computational approaches, we identified here two regions in human NEU1 - segments 139-159 (TM1) and 316-333 (TM2) - as potential transmembrane (TM) domains. In membrane mimicking environments, the corresponding peptides form stable α-helices and TM2 is suited for self-association. This was confirmed with full-size NEU1 by co-immunoprecipitations from membrane preparations and split-ubiquitin yeast two hybrids. The TM2 region was shown to be critical for dimerization since introduction of point mutations within TM2 leads to disruption of NEU1 dimerization and decrease of sialidase activity in membrane. In conclusion, these results bring new insights in the molecular organization of membrane-bound NEU1 and demonstrate, for the first time, the presence of two potential TM domains that may anchor NEU1 in the membrane, control its dimerization and sialidase activity.

Identification of pyrrolo[3,2-c]pyridin-4-amine compounds as a new class of entry inhibitors against influenza viruses in vitro

International Nuclear Information System (INIS)

Chang, So Young; Cruz, Deu John M.; Ko, Yoonae; Min, Ji-Young

2016-01-01

Various influenza virus entry inhibitors are being developed as therapeutic antiviral agents in ongoing preparation for emerging influenza viruses, particularly those that may possess drug resistance to the current FDA-approved neuraminidase inhibitors. In this study, small molecules having the pyrrolopyridinamine (PPA), aminothiadiazole (ATD), dihydrofuropyridine carboxamide (HPC), or imidazopyridinamine (IPA) moiety were selected from a target-focused chemical library for their inhibitory activity against influenza A virus by high-throughput screening using the PR8GFP assay. Activity was evaluated by measuring changes the proportion of GFP-expressing cells as a reflection of influenza virus infection. Among them, PPA showed broad-spectrum activity against multiple influenza A viruses and influenza B virus. PPA was found to block the early stages of influenza virus infection using a time-of-addition assay. Using additional phenotypic assays that dissect the virus entry process, it appears that the antiviral activity of PPA against influenza virus can be attributed to interference of the post-fusion process: namely, virus uncoating and nuclear import of viral nucleoprotein complexes. Based on these results, PPA is an attractive chemical moiety that can be used to develop new antiviral drug candidates against influenza viruses. - Highlights: • Four chemical classes are identified from target-focused chemical library by HTS. • PPA inhibits the infection of various influenza A viruses and influenza B virus. • PPA is identified to inhibit the early stages of influenza virus infection. • PPA compound disrupts virus uncoating and nuclear import of viral ribonucleoprotein.

Neuraminidase stalk length and additional glycosylation of the hemagglutinin influence the virulence of influenza H5N1 viruses for mice.

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Matsuoka, Yumiko; Swayne, David E; Thomas, Colleen; Rameix-Welti, Marie-Anne; Naffakh, Nadia; Warnes, Christine; Altholtz, Melanie; Donis, Ruben; Subbarao, Kanta

2009-05-01

Following circulation of avian influenza H5 and H7 viruses in poultry, the hemagglutinin (HA) can acquire additional glycosylation sites, and the neuraminidase (NA) stalk becomes shorter. We investigated whether these features play a role in the pathogenesis of infection in mammalian hosts. From 1996 to 2007, H5N1 viruses with a short NA stalk have become widespread in several avian species. Compared to viruses with a long-stalk NA, viruses with a short-stalk NA showed a decreased capacity to elute from red blood cells and an increased virulence in mice, but not in chickens. The presence of additional HA glycosylation sites had less of an effect on virulence than did NA stalk length. The short-stalk NA of H5N1 viruses circulating in Asia may contribute to virulence in humans.

Neuraminidase Stalk Length and Additional Glycosylation of the Hemagglutinin Influence the Virulence of Influenza H5N1 Viruses for Mice▿

Science.gov (United States)

Matsuoka, Yumiko; Swayne, David E.; Thomas, Colleen; Rameix-Welti, Marie-Anne; Naffakh, Nadia; Warnes, Christine; Altholtz, Melanie; Donis, Ruben; Subbarao, Kanta

2009-01-01

Following circulation of avian influenza H5 and H7 viruses in poultry, the hemagglutinin (HA) can acquire additional glycosylation sites, and the neuraminidase (NA) stalk becomes shorter. We investigated whether these features play a role in the pathogenesis of infection in mammalian hosts. From 1996 to 2007, H5N1 viruses with a short NA stalk have become widespread in several avian species. Compared to viruses with a long-stalk NA, viruses with a short-stalk NA showed a decreased capacity to elute from red blood cells and an increased virulence in mice, but not in chickens. The presence of additional HA glycosylation sites had less of an effect on virulence than did NA stalk length. The short-stalk NA of H5N1 viruses circulating in Asia may contribute to virulence in humans. PMID:19225004

Structure of the parainfluenza virus 5 (PIV5 hemagglutinin-neuraminidase (HN ectodomain.

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Brett D Welch

Full Text Available Paramyxoviruses cause a wide variety of human and animal diseases. They infect host cells using the coordinated action of two surface glycoproteins, the receptor binding protein (HN, H, or G and the fusion protein (F. HN binds sialic acid on host cells (hemagglutinin activity and hydrolyzes these receptors during viral egress (neuraminidase activity, NA. Additionally, receptor binding is thought to induce a conformational change in HN that subsequently triggers major refolding in homotypic F, resulting in fusion of virus and target cell membranes. HN is an oligomeric type II transmembrane protein with a short cytoplasmic domain and a large ectodomain comprising a long helical stalk and large globular head domain containing the enzymatic functions (NA domain. Extensive biochemical characterization has revealed that HN-stalk residues determine F specificity and activation. However, the F/HN interaction and the mechanisms whereby receptor binding regulates F activation are poorly defined. Recently, a structure of Newcastle disease virus (NDV HN ectodomain revealed the heads (NA domains in a "4-heads-down" conformation whereby two of the heads form a symmetrical interaction with two sides of the stalk. The interface includes stalk residues implicated in triggering F, and the heads sterically shield these residues from interaction with F (at least on two sides. Here we report the x-ray crystal structure of parainfluenza virus 5 (PIV5 HN ectodomain in a "2-heads-up/2-heads-down" conformation where two heads (covalent dimers are in the "down position," forming a similar interface as observed in the NDV HN ectodomain structure, and two heads are in an "up position." The structure supports a model in which the heads of HN transition from down to up upon receptor binding thereby releasing steric constraints and facilitating the interaction between critical HN-stalk residues and F.

In situ molecular identification of the Influenza A (H1N1 2009 Neuraminidase in patients with severe and fatal infections during a pandemic in Mexico City

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Ocadiz-Delgado Rodolfo

2013-01-01

Full Text Available Abstract Background In April 2009, public health surveillance detected an increased number of influenza-like illnesses in Mexico City’s hospitals. The etiological agent was subsequently determined to be a spread of a worldwide novel influenza A (H1N1 triple reassortant. The purpose of the present study was to demonstrate that molecular detection of pandemic influenza A (H1N1 2009 strains is possible in archival material such as paraffin-embedded lung samples. Methods In order to detect A (H1N1 virus sequences in archived biological samples, eight paraffin-embedded lung samples from patients who died of pneumonia and respiratory failure were tested for influenza A (H1N1 Neuraminidase (NA RNA using in situ RT-PCR. Results We detected NA transcripts in 100% of the previously diagnosed A (H1N1-positive samples as a cytoplasmic signal. No expression was detected by in situ RT-PCR in two Influenza-like Illness A (H1N1-negative patients using standard protocols nor in a non-related cervical cell line. In situ relative transcription levels correlated with those obtained when in vitro RT-PCR assays were performed. Partial sequences of the NA gene from A (H1N1-positive patients were obtained by the in situ RT-PCR-sequencing method. Sequence analysis showed 98% similarity with influenza viruses reported previously in other places. Conclusions We have successfully amplified specific influenza A (H1N1 NA sequences using stored clinical material; results suggest that this strategy could be useful when clinical RNA samples are quantity limited, or when poor quality is obtained. Here, we provide a very sensitive method that specifically detects the neuraminidase viral RNA in lung samples from patients who died from pneumonia caused by Influenza A (H1N1 outbreak in Mexico City.

Punctuated Evolution of Influenza Virus Neuraminidase (A/H1N1 under Opposing Migration and Vaccination Pressures

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J. C. Phillips

2014-01-01

Full Text Available Influenza virus contains two highly variable envelope glycoproteins, hemagglutinin (HA and neuraminidase (NA. The structure and properties of HA, which is responsible for binding the virus to the cell that is being infected, change significantly when the virus is transmitted from avian or swine species to humans. Here we focus first on the simpler problem of the much smaller human individual evolutionary amino acid mutational changes in NA, which cleaves sialic acid groups and is required for influenza virus replication. Our thermodynamic panorama shows that very small amino acid changes can be monitored very accurately across many historic (1945–2011 Uniprot and NCBI strains using hydropathicity scales to quantify the roughness of water film packages. Quantitative sequential analysis is most effective with the fractal differential hydropathicity scale based on protein self-organized criticality (SOC. Our analysis shows that large-scale vaccination programs have been responsible for a very large convergent reduction in common influenza severity in the last century. Hydropathic analysis is capable of interpreting and even predicting trends of functional changes in mutation prolific viruses directly from amino acid sequences alone. An engineered strain of NA1 is described which could well be significantly less virulent than current circulating strains.

Oseltamivir

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... regular or sugar-free chocolate syrup, corn syrup, caramel topping, or light brown sugar dissolved in water ... weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and ...

Safety and Pharmacokinetics of Intravenous Zanamivir Treatment in Hospitalized Adults With Influenza: An Open-label, Multicenter, Single-Arm, Phase II Study

OpenAIRE

Marty, Francisco M.; Man, Choy Y.; van der Horst, Charles; Francois, Bruno; Garot, Denis; Máňez, Rafael; Thamlikitkul, Visanu; Lorente, José A.; Álvarez-Lerma, Francisco; Brealey, David; Zhao, Henry H.; Weller, Steve; Yates, Phillip J.; Peppercorn, Amanda F.

2013-01-01

Intravenous zanamivir is a neuraminidase inhibitor suitable for treatment of hospitalized patients with severe influenza. Patients were treated with intravenous zanamivir 600 mg twice daily, adjusted for renal impairment, for up to 10 days. Primary outcomes included adverse events (AEs), and clinical/laboratory parameters. Pharmacokinetics, viral load, and disease course were also assessed. 5.997 JCR (2014) Q1, 18/148 Inmunology, 4/78 Infectious diseases, 14/119 Microbiology UEM

Full-Genome Analysis of Avian Influenza A(H5N1) Virus from a Human, North America, 2013

Science.gov (United States)

Pabbaraju, Kanti; Tellier, Raymond; Wong, Sallene; Li, Yan; Bastien, Nathalie; Tang, Julian W.; Drews, Steven J.; Jang, Yunho; Davis, C. Todd; Tipples, Graham A.

2014-01-01

Full-genome analysis was conducted on the first isolate of a highly pathogenic avian influenza A(H5N1) virus from a human in North America. The virus has a hemagglutinin gene of clade 2.3.2.1c and is a reassortant with an H9N2 subtype lineage polymerase basic 2 gene. No mutations conferring resistance to adamantanes or neuraminidase inhibitors were found. PMID:24755439

Rapid detection and subtyping of European swine influenza viruses in porcine clinical samples by haemagglutinin- and neuraminidase-specific tetra- and triplex real-time RT-PCRs

DEFF Research Database (Denmark)

Henritzi, Dinah; Zhao, Na; Starick, Elke

2016-01-01

diagnostic methods which allow for cost-effective large-scale analysis. Methods New SIV haemagglutinin (HA) and neuraminidase (NA) subtype- and lineage-specific multiplex real-time RT-PCRs (RT-qPCR) have been developed and validated with reference virus isolates and clinical samples. Results A diagnostic....... Swine influenza viruses (SIV) are widespread in European domestic pig populations and evolve dynamically. Knowledge regarding occurrence, spread and evolution of potentially zoonotic SIV in Europe is poorly understood. Objectives Efficient SIV surveillance programmes depend on sensitive and specific......Background A diversifying pool of mammalian-adapted influenza A viruses (IAV) with largely unknown zoonotic potential is maintained in domestic swine populations worldwide. The most recent human influenza pandemic in 2009 was caused by a virus with genes originating from IAV isolated from swine...

A non-biological method for screening active components against influenza virus from traditional Chinese medicine by coupling a LC column with oseltamivir molecularly imprinted polymers.

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Ya-Jun Yang

Full Text Available To develop a non-biological method for screening active components against influenza virus from traditional Chinese medicine (TCM extraction, a liquid chromatography (LC column prepared with oseltamivir molecularly imprinted polymer (OSMIP was employed with LC-mass spectrometry (LC-MS. From chloroform extracts of compound TCM liquid preparation, we observed an affinitive component m/z 249, which was identified to be matrine following analysis of phytochemical literatures, OSMIP-LC column on-line of control compounds and MS/MS off-line. The results showed that matrine had similar bioactivities with OS against avian influenza virus H9N2 in vitro for both alleviating cytopathic effect and hemagglutination inhibition and that the stereostructures of these two compounds are similar while their two-dimensional structures were different. In addition, our results suggested that the bioactivities of those affinitive compounds were correlated with their chromatographic behaviors, in which less difference of the chromatographic behaviors might have more similar bioactivities. This indicates that matrine is a potential candidate drug to prevent or cure influenza for human or animal. In conclusion, the present study showed that molecularly imprinted polymers can be used as a non-biological method for screening active components against influenza virus from TCM.

Inhibitors

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... JM, and the Hemophilia Inhibitor Research Study Investigators. Validation of Nijmegen-Bethesda assay modifications to allow inhibitor ... webinars on blood disorders Language: English (US) Español (Spanish) File Formats Help: How do I view different ...

Shikimic acid production in Escherichia coli: From classical metabolic engineering strategies to omics applied to improve its production

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Juan Andrés Martínez

2015-09-01

Full Text Available Shikimic acid (SA is an intermediate of the SA pathway that is present in bacteria and plants. SA has gained great interest because it is a precursor in the synthesis of the drug oseltamivir phosphate (OSF, an efficient inhibitor of the neuraminidase enzyme of diverse seasonal influenza viruses, the avian influenza virus H5N1, and the human influenza virus H1N1. For the purposes of OSF production, SA is extracted from the pods of Chinese star anise plants (Illicium spp., yielding up to 17% of SA (dry basis content. The high demand for OSF necessary to manage a major influenza outbreak is not adequately met by industrial production using SA from plants sources. As the SA pathway is present in the model bacteria Escherichia coli, several intuitive metabolically engineered strains have been applied for its successful overproduction by biotechnological processes, resulting in strains producing up to 71 g/L of SA, with high conversion yields of up to 0.42 (mol SA/mol Glc, in both batch and fed-batch cultures using complex fermentation broths, including glucose as a carbon source and yeast extract. Global transcriptomic analyses have been performed in SA producing strains, resulting in the identification of possible key target genes for the design of a rational strain improvement strategy. Because possible target genes are involved in the transport, catabolism and interconversion of different carbon sources and metabolic intermediates outside the central carbon metabolism and SA pathways, as genes involved in diverse cellular stress responses, the development of rational cellular strain improvement strategies based on omics data constitutes a challenging task to improve SA production in currently overproducing engineered strains. In this review, we discuss the main metabolic engineering strategies that have been applied for the development of efficient SA producing strains, as the perspective of omics analysis has focused on further strain improvement

Anti-viral properties and mode of action of standardized Echinacea purpurea extract against highly pathogenic avian Influenza virus (H5N1, H7N7 and swine-origin H1N1 (S-OIV

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Schoop Roland

2009-11-01

Full Text Available Abstract Background Influenza virus (IV infections are a major threat to human welfare and animal health worldwide. Anti-viral therapy includes vaccines and a few anti-viral drugs. However vaccines are not always available in time, as demonstrated by the emergence of the new 2009 H1N1-type pandemic strain of swine origin (S-OIV in April 2009, and the acquisition of resistance to neuraminidase inhibitors such as Tamiflu® (oseltamivir is a potential problem. Therefore the prospects for the control of IV by existing anti-viral drugs are limited. As an alternative approach to the common anti-virals we studied in more detail a commercial standardized extract of the widely used herb Echinacea purpurea (Echinaforce®, EF in order to elucidate the nature of its anti-IV activity. Results Human H1N1-type IV, highly pathogenic avian IV (HPAIV of the H5- and H7-types, as well as swine origin IV (S-OIV, H1N1, were all inactivated in cell culture assays by the EF preparation at concentrations ranging from the recommended dose for oral consumption to several orders of magnitude lower. Detailed studies with the H5N1 HPAIV strain indicated that direct contact between EF and virus was required, prior to infection, in order to obtain maximum inhibition in virus replication. Hemagglutination assays showed that the extract inhibited the receptor binding activity of the virus, suggesting that the extract interferes with the viral entry into cells. In sequential passage studies under treatment in cell culture with the H5N1 virus no EF-resistant variants emerged, in contrast to Tamiflu®, which produced resistant viruses upon passaging. Furthermore, the Tamiflu®-resistant virus was just as susceptible to EF as the wild type virus. Conclusion As a result of these investigations, we believe that this standard Echinacea preparation, used at the recommended dose for oral consumption, could be a useful, readily available and affordable addition to existing control options

The leukocyte common antigen (CD45) on human pre-B leukemia cells: variant glycoprotein form expression during the cell exposure to phorbol ester is blocked by a nonselective protein kinase inhibitor H7

International Nuclear Information System (INIS)

Duraj, J.; Sedlak, J.; Chorvath, B.; Rauko, P.

1997-01-01

The human pre-B acute lymphoblastic leukemia cell line REH6 was utilized for characterization of CD45 glycoprotein by monoclonal antibodies (mAb) recognizing four distinct CD45 antigen specificities, i.e. nonrestricted CD45, restricted, CD45RA, CD45RB and CD45R0. Immunoprecipitation revealed two antigen specificities on REH6 cells of m.w. 220 kDa and 190 kDa, both presenting wide range of isoelectric point pI∼6.0-7.5. Nonrestricted CD45 epitopes were not affected by the sialyl acid cleavage with sodium meta-periodate or neuraminidase, but were sensitive to both, tunicamycin, the N-glycosylation inhibitor and monensin, an inhibitor of protein transport through the Golgi compartment. O-sialoglycoprotein endopeptidase from Pasteurella haemolytica A1 partially cleaved CD45RA and CD45RB epitopes, while nonrestricted CD45 determinants were not affected by this enzyme. Limited proteolysis of this antigen resulted in the appearance of 160-180 kDa peptide domains which retained CD45 epitopes. Further, the treatment of cells with phorbol myristate acetate (PMA) induced marked down-regulation of 220 and 190 kDa isoforms and the appearance of new 210, 180 and 170 kDa variant glycoprotein forms which were not found on parental cells. This PMA effect was not accompanied by the programmed cell death and was markedly blocked by a nonselective protein kinase (PK) inhibitor iso-quinoline sulfonamide H7. Modulation of CD45 by phorbol esters might serve as an in vitro model for an additional insight into the function of CD45 in hematopoietic cells. (author)

Genetic diversity of the 2009 pandemic influenza A(H1N1 viruses in Finland.

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Niina Ikonen

Full Text Available BACKGROUND: In Finland, the first infections caused by the 2009 pandemic influenza A(H1N1 virus were identified on May 10. During the next three months almost all infections were found from patients who had recently traveled abroad. In September 2009 the pandemic virus started to spread in the general population, leading to localized outbreaks and peak epidemic activity was reached during weeks 43-48. METHODS/RESULTS: The nucleotide sequences of the hemagglutinin (HA and neuraminidase (NA genes from viruses collected from 138 patients were determined. The analyzed viruses represented mild and severe infections and different geographic regions and time periods. Based on HA and NA gene sequences, the Finnish pandemic viruses clustered in four groups. Finnish epidemic viruses and A/California/07/2009 vaccine virus strain varied from 2-8 and 0-5 amino acids in HA and NA molecules, respectively, giving a respective maximal evolution speed of 1.4% and 1.1%. Most amino acid changes in HA and NA molecules accumulated on the surface of the molecule and were partly located in antigenic sites. Three severe infections were detected with a mutation at HA residue 222, in two viruses with a change D222G, and in one virus D222Y. Also viruses with change D222E were identified. All Finnish pandemic viruses were sensitive to oseltamivir having the amino acid histidine at residue 275 of the neuraminidase molecule. CONCLUSIONS: The Finnish pandemic viruses were quite closely related to A/California/07/2009 vaccine virus. Neither in the HA nor in the NA were changes identified that may lead to the selection of a virus with increased epidemic potential or exceptionally high virulence. Continued laboratory-based surveillance of the 2009 pandemic influenza A(H1N1 is important in order to rapidly identify drug resistant viruses and/or virus variants with potential ability to cause severe forms of infection and an ability to circumvent vaccine-induced immunity.

[Contemporary threat of influenza virus infection].

Science.gov (United States)

Płusa, Tadeusz

2010-01-01

Swine-origine H1N1 influenza virus (S-OIV) caused a great mobilization of health medical service over the world. Now it is well known that a vaccine against novel virus is expected as a key point in that battle. In the situation when recommended treatment with neuraminidase inhibitors is not sufficient to control influenza A/H1N1 viral infection the quick and precisely diagnostic procedures should be applied to save and protect our patients.

Glycosylation of Hemagglutinin and Neuraminidase of Influenza A Virus as Signature for Ecological Spillover and Adaptation among Influenza Reservoirs

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Paul Kim

2018-04-01

Full Text Available Glycosylation of the hemagglutinin (HA and neuraminidase (NA of the influenza provides crucial means for immune evasion and viral fitness in a host population. However, the time-dependent dynamics of each glycosylation sites have not been addressed. We monitored the potential N-linked glycosylation (NLG sites of over 10,000 HA and NA of H1N1 subtype isolated from human, avian, and swine species over the past century. The results show a shift in glycosylation sites as a hallmark of 1918 and 2009 pandemics, and also for the 1976 “abortive pandemic”. Co-segregation of particular glycosylation sites was identified as a characteristic of zoonotic transmission from animal reservoirs, and interestingly, of “reverse zoonosis” of human viruses into swine populations as well. After the 2009 pandemic, recent isolates accrued glycosylation at canonical sites in HA, reflecting gradual seasonal adaptation, and a novel glycosylation in NA as an independent signature for adaptation among humans. Structural predictions indicated a remarkably pleiotropic influence of glycans on multiple HA epitopes for immune evasion, without sacrificing the receptor binding of HA or the activity of NA. The results provided the rationale for establishing the ecological niche of influenza viruses among the reservoir and could be implemented for influenza surveillance and improving pandemic preparedness.

Glycosylation of Hemagglutinin and Neuraminidase of Influenza A Virus as Signature for Ecological Spillover and Adaptation among Influenza Reservoirs

Science.gov (United States)

Kim, Paul; Jang, Yo Han; Kwon, Soon Bin; Lee, Chung Min; Han, Gyoonhee; Seong, Baik Lin

2018-01-01

Glycosylation of the hemagglutinin (HA) and neuraminidase (NA) of the influenza provides crucial means for immune evasion and viral fitness in a host population. However, the time-dependent dynamics of each glycosylation sites have not been addressed. We monitored the potential N-linked glycosylation (NLG) sites of over 10,000 HA and NA of H1N1 subtype isolated from human, avian, and swine species over the past century. The results show a shift in glycosylation sites as a hallmark of 1918 and 2009 pandemics, and also for the 1976 “abortive pandemic”. Co-segregation of particular glycosylation sites was identified as a characteristic of zoonotic transmission from animal reservoirs, and interestingly, of “reverse zoonosis” of human viruses into swine populations as well. After the 2009 pandemic, recent isolates accrued glycosylation at canonical sites in HA, reflecting gradual seasonal adaptation, and a novel glycosylation in NA as an independent signature for adaptation among humans. Structural predictions indicated a remarkably pleiotropic influence of glycans on multiple HA epitopes for immune evasion, without sacrificing the receptor binding of HA or the activity of NA. The results provided the rationale for establishing the ecological niche of influenza viruses among the reservoir and could be implemented for influenza surveillance and improving pandemic preparedness. PMID:29642453

Isolation of Panels of Llama Single-Domain Antibody Fragments Binding All Nine Neuraminidase Subtypes of Influenza A Virus

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Guus Koch

2013-04-01

Full Text Available Avian influenza A virus comprises sixteen hemagglutinin (HA and nine neuraminidase (NA subtypes (N1–N9. To isolate llama single-domain antibody fragments (VHHs against all N subtypes, four llamas were immunized with mixtures of influenza viruses. Selections using influenza virus yielded predominantly VHHs binding to the highly immunogenic HA and nucleoprotein. However, selection using enzymatically active recombinant NA (rNA protein enabled us to isolate NA binding VHHs. Some isolated VHHs cross-reacted to other N subtypes. These were subsequently used for the capture of N subtypes that could not be produced as recombinant protein (rN6 or were enzymatically inactive (rN1, rN5 in phage display selection, yielding novel VHHs. In total we isolated 188 NA binding VHHs, 64 of which were expressed in yeast. Most VHHs specifically recognize a single N subtype, but some VHHs cross-react with other N-subtypes. At least one VHH bound to all N subtypes, except N4, identifying a conserved antigenic site. Thus, this work (1 describes methods for isolating NA binding VHHs, (2 illustrates the suitability of llama immunization with multiple antigens for retrieving many binders against different antigens and (3 describes 64 novel NA binding VHHs, including a broadly reactive VHH, which can be used in various assays for influenza virus subtyping, detection or serology.

Neuraminidase and hemagglutinin matching patterns of a highly pathogenic avian and two pandemic H1N1 influenza A viruses.

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Yonghui Zhang

Full Text Available BACKGROUND: Influenza A virus displays strong reassortment characteristics, which enable it to achieve adaptation in human infection. Surveying the reassortment and virulence of novel viruses is important in the prevention and control of an influenza pandemic. Meanwhile, studying the mechanism of reassortment may accelerate the development of anti-influenza strategies. METHODOLOGY/PRINCIPAL FINDINGS: The hemagglutinin (HA and neuraminidase (NA matching patterns of two pandemic H1N1 viruses (the 1918 and current 2009 strains and a highly pathogenic avian influenza A virus (H5N1 were studied using a pseudotyped particle (pp system. Our data showed that four of the six chimeric HA/NA combinations could produce infectious pps, and that some of the chimeric pps had greater infectivity than did their ancestors, raising the possibility of reassortment among these viruses. The NA of H5N1 (A/Anhui/1/2005 could hardly reassort with the HAs of the two H1N1 viruses. Many biological characteristics of HA and NA, including infectivity, hemagglutinating ability, and NA activity, are dependent on their matching pattern. CONCLUSIONS/SIGNIFICANCE: Our data suggest the existence of an interaction between HA and NA, and the HA NA matching pattern is critical for valid viral reassortment.

Discovery of natural mouse serum derived HIV-1 entry inhibitor(s).

Science.gov (United States)

Wei, M; Chen, Y; Xi, J; Ru, S; Ji, M; Zhang, D; Fang, Q; Tang, B

Among rationally designed human immunodeficiency virus 1 (HIV-1) inhibitors, diverse natural factors have showed as potent anti-HIV activity in human blood. We have discovered that the boiled supernatant of healthy mouse serum could suppress HIV-1 entry, and exhibited reduced inhibitory activity after trypsin digestion. Further analysis demonstrated that only the fraction containing 10-25 K proteins could inhibit HIV-1 mediated cell-cell fusion. These results suggest that the 10-25 K protein(s) is novel natural HIV-1 entry inhibitor(s). Our findings provide important information about novel natural HIV entry inhibitors in mouse serum.

Positive Selection on Hemagglutinin and Neuraminidase Genes of H1N1 Influenza Viruses

LENUS (Irish Health Repository)

Li, Wenfu

2011-04-21

Abstract Background Since its emergence in March 2009, the pandemic 2009 H1N1 influenza A virus has posed a serious threat to public health. To trace the evolutionary path of these new pathogens, we performed a selection-pressure analysis of a large number of hemagglutinin (HA) and neuraminidase (NA) gene sequences of H1N1 influenza viruses from different hosts. Results Phylogenetic analysis revealed that both HA and NA genes have evolved into five distinct clusters, with further analyses indicating that the pandemic 2009 strains have experienced the strongest positive selection. We also found evidence of strong selection acting on the seasonal human H1N1 isolates. However, swine viruses from North America and Eurasia were under weak positive selection, while there was no significant evidence of positive selection acting on the avian isolates. A site-by-site analysis revealed that the positively selected sites were located in both of the cleaved products of HA (HA1 and HA2), as well as NA. In addition, the pandemic 2009 strains were subject to differential selection pressures compared to seasonal human, North American swine and Eurasian swine H1N1 viruses. Conclusions Most of these positively and\\/or differentially selected sites were situated in the B-cell and\\/or T-cell antigenic regions, suggesting that selection at these sites might be responsible for the antigenic variation of the viruses. Moreover, some sites were also associated with glycosylation and receptor-binding ability. Thus, selection at these positions might have helped the pandemic 2009 H1N1 viruses to adapt to the new hosts after they were introduced from pigs to humans. Positive selection on position 274 of NA protein, associated with drug resistance, might account for the prevalence of drug-resistant variants of seasonal human H1N1 influenza viruses, but there was no evidence that positive selection was responsible for the spread of the drug resistance of the pandemic H1N1 strains.

Fluorinated Amine Stereotriads via Allene Amination.

Science.gov (United States)

Liu, Lu; Gerstner, Nels C; Oxtoby, Lucas J; Guzei, Ilia A; Schomaker, Jennifer M

2017-06-16

The incorporation of fluorine into organic scaffolds often improves the bioactivity of pharmaceutically relevant compounds. C-F/C-N/C-O stereotriad motifs are prevalent in antivirals, neuraminidase inhibitors, and modulators of androgen receptors, but are challenging to install. An oxidative allene amination strategy using Selectfluor rapidly delivers triply functionalized triads of the form C-F/C-N/C-O, exhibiting good scope and diastereoselectivity for all syn products. The resulting stereotriads are readily transformed into fluorinated pyrrolidines and protected α-, β-, and γ-amino acids.

Human Infection with Highly Pathogenic Avian Influenza A(H7N9) Virus, China.

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Ke, Changwen; Mok, Chris Ka Pun; Zhu, Wenfei; Zhou, Haibo; He, Jianfeng; Guan, Wenda; Wu, Jie; Song, Wenjun; Wang, Dayan; Liu, Jiexiong; Lin, Qinhan; Chu, Daniel Ka Wing; Yang, Lei; Zhong, Nanshan; Yang, Zifeng; Shu, Yuelong; Peiris, Joseph Sriyal Malik

2017-07-01

The recent increase in zoonotic avian influenza A(H7N9) disease in China is a cause of public health concern. Most of the A(H7N9) viruses previously reported have been of low pathogenicity. We report the fatal case of a patient in China who was infected with an A(H7N9) virus having a polybasic amino acid sequence at its hemagglutinin cleavage site (PEVPKRKRTAR/GL), a sequence suggestive of high pathogenicity in birds. Its neuraminidase also had R292K, an amino acid change known to be associated with neuraminidase inhibitor resistance. Both of these molecular features might have contributed to the patient's adverse clinical outcome. The patient had a history of exposure to sick and dying poultry, and his close contacts had no evidence of A(H7N9) disease, suggesting human-to-human transmission did not occur. Enhanced surveillance is needed to determine whether this highly pathogenic avian influenza A(H7N9) virus will continue to spread.

The effect of chemical anti-inhibitors on fibrinolytic enzymes and inhibitors

DEFF Research Database (Denmark)

Sidelmann, Johannes Jakobsen; Jespersen, J; Kluft, C

1997-01-01

proteases. We studied the influence of chemical anti-inhibitors (chloramine T, flufenamate, sodium lauryl sulfate, and methylamine) on fibrinolytic serine proteases and fibrinolytic enzyme inhibitors using the physiological substrate fibrin as plasmin substrate. Low concentrations of chloramine T (0.01 mmol......%) and plasminogen activators (apparent recovery > 200%). Sodium lauryl sulfate eliminates the major fibrinolytic enzyme inhibitors, but increases the activity of plasmin (apparent recovery > 200%) and plasminogen activator, urokinase type (apparent recovery 130%). Methylamine affects only plasmin inhibition. We...

Combined effects of EGFR tyrosine kinase inhibitors and vATPase inhibitors in NSCLC cells

Energy Technology Data Exchange (ETDEWEB)

Jin, Hyeon-Ok [KIRAMS Radiation Biobank, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Hong, Sung-Eun [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Kim, Chang Soon [Department of Microbiological Engineering, Kon-Kuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143–701 (Korea, Republic of); Park, Jin-Ah; Kim, Jin-Hee; Kim, Ji-Young; Kim, Bora [KIRAMS Radiation Biobank, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Chang, Yoon Hwan; Hong, Seok-Il; Hong, Young Jun [Department of Laboratory Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Park, In-Chul, E-mail: parkic@kirams.re.kr [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Lee, Jin Kyung, E-mail: jklee@kirams.re.kr [KIRAMS Radiation Biobank, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Department of Laboratory Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of)

2015-08-15

Despite excellent initial clinical responses of non-small cell lung cancer (NSCLC) patients to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), many patients eventually develop resistance. According to a recent report, vacuolar H + ATPase (vATPase) is overexpressed and is associated with chemotherapy drug resistance in NSCLC. We investigated the combined effects of EGFR TKIs and vATPase inhibitors and their underlying mechanisms in the regulation of NSCLC cell death. We found that combined treatment with EGFR TKIs (erlotinib, gefitinib, or lapatinib) and vATPase inhibitors (bafilomycin A1 or concanamycin A) enhanced synergistic cell death compared to treatments with each drug alone. Treatment with bafilomycin A1 or concanamycin A led to the induction of Bnip3 expression in an Hif-1α dependent manner. Knock-down of Hif-1α or Bnip3 by siRNA further enhanced cell death induced by bafilomycin A1, suggesting that Hif-1α/Bnip3 induction promoted resistance to cell death induced by the vATPase inhibitors. EGFR TKIs suppressed Hif-1α and Bnip3 expression induced by the vATPase inhibitors, suggesting that they enhanced the sensitivity of the cells to these inhibitors by decreasing Hif-1α/Bnip3 expression. Taken together, we conclude that EGFR TKIs enhance the sensitivity of NSCLC cells to vATPase inhibitors by decreasing Hif-1α/Bnip3 expression. We suggest that combined treatment with EGFR TKIs and vATPase inhibitors is potentially effective for the treatment of NSCLC. - Highlights: • Co-treatment with EGFR TKIs and vATPase inhibitors induces synergistic cell death • EGFR TKIs enhance cell sensitivity to vATPase inhibitors via Hif-1α downregulation • Co-treatment of these inhibitors is potentially effective for the treatment of NSCLC.

ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors.

Science.gov (United States)

Halasi, Marianna; Wang, Ming; Chavan, Tanmay S; Gaponenko, Vadim; Hay, Nissim; Gartel, Andrei L

2013-09-01

NAC (N-acetyl-L-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H₂O₂. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabilization, apoptosis and accumulation of ubiquitin conjugates. These observations suggest that NAC has a dual activity as an inhibitor of ROS and proteasome inhibitors. Recently, NAC was used as a ROS inhibitor to functionally characterize a novel anticancer compound, piperlongumine, leading to its description as a ROS inducer. In contrast, our own experiments showed that this compound depicts features of proteasome inhibitors including suppression of FOXM1 (Forkhead box protein M1), stabilization of cellular proteins, induction of ROS-independent apoptosis and enhanced accumulation of ubiquitin conjugates. In addition, NAC, but not catalase or Trolox, interfered with the activity of piperlongumine, further supporting that piperlongumine is a proteasome inhibitor. Most importantly, we showed that NAC, but not other ROS scavengers, directly binds to proteasome inhibitors. To our knowledge, NAC is the first known compound that directly interacts with and antagonizes the activity of proteasome inhibitors. Taken together, the findings of the present study suggest that, as a result of the dual nature of NAC, data interpretation might not be straightforward when NAC is utilized as an antioxidant to demonstrate ROS involvement in drug-induced apoptosis.

Synergistic apoptosis induction in leukemic cells by the phosphatase inhibitor salubrinal and proteasome inhibitors.

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Hannes C A Drexler

Full Text Available Cells adapt to endoplasmic reticulum (ER-stress by arresting global protein synthesis while simultaneously activating specific transcription factors and their downstream targets. These processes are mediated in part by the phosphorylation-dependent inactivation of the translation initiation factor eIF2alpha. Following restoration of homeostasis protein synthesis is resumed when the serine/threonine-protein phosphatase PP1 dephosphorylates and reactivates eIF2alpha. Proteasome inhibitors, used to treat multiple myeloma patients evoke ER-stress and apoptosis by blocking the ER-associated degradation of misfolded proteins (ERAD, however, the role of eIF2alpha phosphorylation in leukemic cells under conditions of proteasome inhibitor-mediated ER stress is currently unclear.Bcr-Abl-positive and negative leukemic cell lines were used to investigate the functional implications of PP1-related phosphatase activities on eIF2alpha phosphorylation in proteasome inhibitor-mediated ER stress and apoptosis. Rather unexpectedly, salubrinal, a recently identified PP1 inhibitor capable to protect against ER stress in various model systems, strongly synergized with proteasome inhibitors to augment apoptotic death of different leukemic cell lines. Salubrinal treatment did not affect the phosphorlyation status of eIF2alpha. Furthermore, the proapoptotic effect of salubrinal occurred independently from the chemical nature of the proteasome inhibitor, was recapitulated by a second unrelated phosphatase inhibitor and was unaffected by overexpression of a dominant negative eIF2alpha S51A variant that can not be phosphorylated. Salubrinal further aggravated ER-stress and proteotoxicity inflicted by the proteasome inhibitors on the leukemic cells since characteristic ER stress responses, such as ATF4 and CHOP synthesis, XBP1 splicing, activation of MAP kinases and eventually apoptosis were efficiently abrogated by the translational inhibitor cycloheximide.Although PP1

Influenza virus inactivation for studies of antigenicity and phenotypic neuraminidase inhibitor resistance profiling

NARCIS (Netherlands)

M. Jonges (Marcel); W.M. Liu; E. van der Vries (Erhard); R. Jacobi (Ronald); I. Pronk (Inge); C. Boog (Claire); M.P.G. Koopmans D.V.M. (Marion); A. Meijer (Adam); E. Soethout (Ernst)

2010-01-01

textabstractIntroduction of a new influenza virus in humans urges quick analysis of its virological and immunological characteristics to determine the impact on public health and to develop protective measures for the human population. At present, however, the necessity of executing pandemic

Chicken galectin-1B inhibits Newcastle disease virus adsorption and replication through binding to hemagglutinin-neuraminidase (HN) glycoprotein.

Science.gov (United States)

Sun, Junfeng; Han, Zongxi; Qi, Tianming; Zhao, Ran; Liu, Shengwang

2017-12-08

Galectin-1 is an important immunoregulatory factor and can mediate the host-pathogen interaction via binding glycans on the surface of various viruses. We previously reported that avian respiratory viruses, including lentogenic Newcastle disease virus (NDV), can induce up-regulation of chicken galectin (CG)-1B in the primary target organ. In this study, we investigated whether CG-1B participated in the infectious process of NDV in chickens. We demonstrated that velogenic NDV induced up-regulation of CG-1B in target organs. We also found that CG-1B directly bound to NDV virions and inhibited their hemagglutination activity in vitro We confirmed that CG-1B interacted with NDV hemagglutinin-neuraminidase (HN) glycoprotein, in which the specific G4 N -glycans significantly contributed to the interaction between CG-1B and HN glycoprotein. The presence of extracellular CG-1B, rather than the internalization process, inhibited adsorption of NDV. The interaction between intracellular CG-1B and NDV HN glycoproteins inhibited cell-surface expression of HN glycoprotein and reduced the titer of progeny virus in NDV-infected DF-1 cells. Significantly, the replication of parental and HN glycosylation mutant viruses in CG-1B knockdown and overexpression cells demonstrated that the replication of NDV was correlated with the expression of CG-1B in a specific glycan-dependent manner. Collectively, our results indicate that CG-1B has anti-NDV activity by binding to N -glycans on HN glycoprotein. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Screening of protein kinase inhibitors identifies PKC inhibitors as inhibitors of osteoclastic acid secretion and bone resorption

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Boutin Jean A

2010-10-01

Full Text Available Abstract Background Bone resorption is initiated by osteoclastic acidification of the resorption lacunae. This process is mediated by secretion of protons through the V-ATPase and chloride through the chloride antiporter ClC-7. To shed light on the intracellular signalling controlling extracellular acidification, we screened a protein kinase inhibitor library in human osteoclasts. Methods Human osteoclasts were generated from CD14+ monocytes. The effect of different kinase inhibitors on lysosomal acidification in human osteoclasts was investigated using acridine orange for different incubation times (45 minutes, 4 and 24 hours. The inhibitors were tested in an acid influx assay using microsomes isolated from human osteoclasts. Bone resorption by human osteoclasts on bone slices was measured by calcium release. Cell viability was measured using AlamarBlue. Results Of the 51 compounds investigated only few inhibitors were positive in both acidification and resorption assays. Rottlerin, GF109203X, Hypericin and Ro31-8220 inhibited acid influx in microsomes and bone resorption, while Sphingosine and Palmitoyl-DL-carnitine-Cl showed low levels of inhibition. Rottlerin inhibited lysosomal acidification in human osteoclasts potently. Conclusions In conclusion, a group of inhibitors all indicated to inhibit PKC reduced acidification in human osteoclasts, and thereby bone resorption, indicating that acid secretion by osteoclasts may be specifically regulated by PKC in osteoclasts.

Prolonged influenza virus shedding and emergence of antiviral resistance in immunocompromised patients and ferrets.

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Erhard van der Vries

Full Text Available Immunocompromised individuals tend to suffer from influenza longer with more serious complications than otherwise healthy patients. Little is known about the impact of prolonged infection and the efficacy of antiviral therapy in these patients. Among all 189 influenza A virus infected immunocompromised patients admitted to ErasmusMC, 71 were hospitalized, since the start of the 2009 H1N1 pandemic. We identified 11 (15% cases with prolonged 2009 pandemic virus replication (longer than 14 days, despite antiviral therapy. In 5 out of these 11 (45% cases oseltamivir resistant H275Y viruses emerged. Given the inherent difficulties in studying antiviral efficacy in immunocompromised patients, we have infected immunocompromised ferrets with either wild-type, or oseltamivir-resistant (H275Y 2009 pandemic virus. All ferrets showed prolonged virus shedding. In wild-type virus infected animals treated with oseltamivir, H275Y resistant variants emerged within a week after infection. Unexpectedly, oseltamivir therapy still proved to be partially protective in animals infected with resistant virus. Immunocompromised ferrets offer an attractive alternative to study efficacy of novel antiviral therapies.

Allosteric small-molecule kinase inhibitors

DEFF Research Database (Denmark)

Wu, Peng; Clausen, Mads Hartvig; Nielsen, Thomas E.

2015-01-01

current barriers of kinase inhibitors, including poor selectivity and emergence of drug resistance. In spite of the small number of identified allosteric inhibitors in comparison with that of inhibitors targeting the ATP pocket, encouraging results, such as the FDA-approval of the first small...

The special neuraminidase stalk-motif responsible for increased virulence and pathogenesis of H5N1 influenza A virus.

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Hongbo Zhou

Full Text Available The variation of highly pathogenic avian influenza H5N1 virus results in gradually increased virulence in poultry, and human cases continue to accumulate. The neuraminidase (NA stalk region of influenza virus varies considerably and may associate with its virulence. The NA stalk region of all N1 subtype influenza A viruses can be divided into six different stalk-motifs, H5N1/2004-like (NA-wt, WSN-like, H5N1/97-like, PR/8-like, H7N1/99-like and H5N1/96-like. The NA-wt is a special NA stalk-motif which was first observed in H5N1 influenza virus in 2000, with a 20-amino acid deletion in the 49(th to 68(th positions of the stalk region. Here we show that there is a gradual increase of the special NA stalk-motif in H5N1 isolates from 2000 to 2007, and notably, the special stalk-motif is observed in all 173 H5N1 human isolates from 2004 to 2007. The recombinant H5N1 virus with the special stalk-motif possesses the highest virulence and pathogenicity in chicken and mice, while the recombinant viruses with the other stalk-motifs display attenuated phenotype. This indicates that the special stalk-motif has contributed to the high virulence and pathogenicity of H5N1 isolates since 2000. The gradually increasing emergence of the special NA stalk-motif in H5N1 isolates, especially in human isolates, deserves attention by all.

Molecular findings from influenza A(H1N1pdm09 detected in patients from a Brazilian equatorial region during the pandemic period

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Maria José Couto Oliveira

2014-11-01

Full Text Available After the World Health Organization officially declared the end of the first pandemic of the XXI century in August 2010, the influenza A(H1N1pdm09 virus has been disseminated in the human population. In spite of its sustained circulation, very little on phylogenetic data or oseltamivir (OST resistance is available for the virus in equatorial regions of South America. In order to shed more light on this topic, we analysed the haemagglutinin (HA and neuraminidase (NA genes of influenza A(H1N1pdm09 positive samples collected during the pandemic period in the Pernambuco (PE, a northeastern Brazilian state. Complete HA sequences were compared and amino acid changes were related to clinical outcome. In addition, the H275Y substitution in NA, associated with OST resistance, was investigated by pyrosequencing. Samples from PE were grouped in phylogenetic clades 6 and 7, being clustered together with sequences from South and Southeast Brazil. The D222N/G HA gene mutation, associated with severity, was found in one deceased patient that was pregnant. Additionally, the HA mutation K308E, which appeared in Brazil in 2010 and was only detected worldwide the following year, was identified in samples from hospitalised cases. The resistance marker H275Y was not identified in samples tested. However, broader studies are needed to establish the real frequency of resistance in this Brazilian region.

Molecular epidemiology of influenza A(H1N1pdm09 viruses from Pakistan in 2009-2010.

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Uzma Bashir Aamir

Full Text Available In early 2009, a novel influenza A(H1N1 virus that emerged in Mexico and United States rapidly disseminated worldwide. The spread of this virus caused considerable morbidity with over 18000 recorded deaths. The new virus was found to be a reassortant containing gene segments from human, avian and swine influenza viruses.The first case of human infection with A(H1N1pdm09 in Pakistan was detected on 18(th June 2009. Since then, 262 laboratory-confirmed cases have been detected during various outbreaks with 29 deaths (as of 31(st August 2010. The peak of the epidemic was observed in December with over 51% of total respiratory cases positive for influenza. Representative isolates from Pakistan viruses were sequenced and analyzed antigenically. Sequence analysis of genes coding for surface glycoproteins HA and NA showed high degree of high levels of sequence identity with corresponding genes of regional viruses circulating South East Asia. All tested viruses were sensitive to Oseltamivir in the Neuraminidase Inhibition assays.Influenza A(H1N1pdm09 viruses from Pakistan form a homogenous group of viruses. Their HA genes belong to clade 7 and show antigenic profile similar to the vaccine strain A/California/07/2009. These isolates do not show any amino acid changes indicative of high pathogenicity and virulence. It is imperative to continue monitoring of these viruses for identification of potential variants of high virulence or drug resistance.

SGLT2 inhibitors.

Science.gov (United States)

Dardi, I; Kouvatsos, T; Jabbour, S A

2016-02-01

Diabetes mellitus is a serious health issue and an economic burden, rising in epidemic proportions over the last few decades worldwide. Although several treatment options are available, only half of the global diabetic population achieves the recommended or individualized glycemic targets. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of antidiabetic agents with a novel insulin-independent action. SGLT2 is a transporter found in the proximal renal tubules, responsible for the reabsorption of most of the glucose filtered by the kidney. Inhibition of SGLT2 lowers the blood glucose level by promoting the urinary excretion of excess glucose. Due to their insulin-independent action, SGLT2 inhibitors can be used with any degree of beta-cell dysfunction or insulin resistance, related to a very low risk of hypoglycemia. In addition to improving glycemic control, SGLT2 inhibitors have been associated with a reduction in weight and blood pressure when used as monotherapy or in combination with other antidiabetic agents in patients with type 2 diabetes mellitus (T2DM). Treatment with SGLT2 inhibitors is usually well tolerated; however, they have been associated with an increased incidence of urinary tract and genital infections, although these infections are usually mild and easy to treat. SGLT2 inhibitors are a promising new option in the armamentarium of drugs for patients with T2DM. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of Vibrio cholerae neuraminidase on the mitogen response of T lymphocytes. I. Enhancement of macrophage T-lymphocyte cooperation in concanavalin-A-induced lymphocyte activation.

Science.gov (United States)

Knop, J

1980-12-01

Vibrio cholerae neuraminidase (VCN) enhances the immune response of lymphocytes in various systems, such as antigen- and mitogen-induced blastogenesis, mixed lymphocyte culture (MLC) and tumor-cell response. We used macrophage-depleted and reconstituted murine lymph-node T-cells to investigate the effect of VCN on macrophage-T-lymphocyte co-operation in Con-A-induced lymphocyte activation. In unfractionated lymph-node cells VCN enhanced the Con-A-induced lymphocyte activation as measured by 3H-thymidine (3H-dThd) incorporation. Removing macrophages from the cells resulted in a significantly diminished response. In addition the enhancing effect of VCN was greatly reduced. Reconstitution of the lymphocyte cultures with macrophages in increasing numbers and from various sources rstored the lymphocyte response and the enhancing effect of VCN. VCN proved to be most efficient in cultures reconstituted with normal peritoneal macrophages. Some effect was also observed using bone-marrow-derived (BM) macrophages. However, higher numbers of normal PE macrophages in the presence of VCN inhibited lymphocyte activation, and inhibition by thioglycollate-broth-induced macrophages was considerably increased by VCN. These results suggest that VCN acts by increasing the efficiency of macrophage-T lymphocyte interaction.

Partial antiviral activities detection of chicken Mx jointing with neuraminidase gene (NA against Newcastle disease virus.

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Yani Zhang

Full Text Available As an attempt to increase the resistance to Newcastle Disease Virus (NDV and so further reduction of its risk on the poultry industry. This work aimed to build the eukaryotic gene co-expression plasmid of neuraminidase (NA gene and myxo-virus resistance (Mx and detect the gene expression in transfected mouse fibroblasts (NIH-3T3 cells, it is most important to investigate the influence of the recombinant plasmid on the chicken embryonic fibroblasts (CEF cells. cDNA fragment of NA and mutant Mx gene were derived from pcDNA3.0-NA and pcDNA3.0-Mx plasmid via PCR, respectively, then NA and Mx cDNA fragment were inserted into the multiple cloning sites of pVITRO2 to generate the eukaryotic co-expression plasmid pVITRO2-Mx-NA. The recombinant plasmid was confirmed by restriction endonuclease treatment and sequencing, and it was transfected into the mouse fibroblasts (NIH-3T3 cells. The expression of genes in pVITRO2-Mx-NA were measured by RT-PCR and indirect immunofluorescence assay (IFA. The recombinant plasmid was transfected into CEF cells then RT-PCR and the micro-cell inhibition tests were used to test the antiviral activity for NDV. Our results showed that co-expression vector pVITRO2-Mx-NA was constructed successfully; the expression of Mx and NA could be detected in both NIH-3T3 and CEF cells. The recombinant proteins of Mx and NA protect CEF cells from NDV infection until after 72 h of incubation but the individually mutagenic Mx protein or NA protein protects CEF cells from NDV infection till 48 h post-infection, and co-transfection group decreased significantly NDV infection compared with single-gene transfection group (P<0. 05, indicating that Mx-NA jointing contributed to delaying the infection of NDV in single-cell level and the co-transfection of the jointed genes was more powerful than single one due to their synergistic effects.

Proteinaceous alpha-araylase inhibitors

DEFF Research Database (Denmark)

Svensson, Birte; Fukuda, Kenji; Nielsen, P.K.

2004-01-01

-amylase inhibitors belong to seven different protein structural families, most of which also contain evolutionary related proteins without inhibitory activity. Two families include bifunctional inhibitors acting both on alpha-amylases and proteases. High-resolution structures are available of target alpha...

Syk inhibitors.

Science.gov (United States)

Chihara, Kazuyasu; Kimura, Yukihiro; Honjo, Chisato; Takeuchi, Kenji; Sada, Kiyonao

2013-01-01

Non-receptor type of protein-tyrosine kinase Syk (spleen tyrosine kinase) was isolated in University of Fukui in 1991. Syk is most highly expressed by haemopoietic cells and known to play crucial roles in the signal transduction through various immunoreceptors of the adaptive immune response. However, recent reports demonstrate that Syk also mediates other biological functions, such as innate immune response, osteoclast maturation, platelet activation and cellular adhesion. Moreover, ectopic expression of Syk by epigenetic changes is reported to cause retinoblastoma. Because of its critical roles on the cellular functions, the development of Syk inhibitors for clinical use has been desired. Although many candidate compounds were produced, none of them had progressed to clinical trials. However, novel Syk inhibitors were finally developed and its usefulness has been evaluated in the treatment of allergic rhinitis, rheumatoid arthritis and idiopathic thrombocytopenic purpura. In this review, we will summarize the history, structure and function of Syk, and then the novel Syk inhibitors and their current status. In addition, we will introduce our research focused on the functions of Syk on Dectin-1-mediated mast cell activation.

Swine Influenza Virus PA and Neuraminidase Gene Reassortment into Human H1N1 Influenza Virus Is Associated with an Altered Pathogenic Phenotype Linked to Increased MIP-2 Expression.

Science.gov (United States)

Dlugolenski, Daniel; Jones, Les; Howerth, Elizabeth; Wentworth, David; Tompkins, S Mark; Tripp, Ralph A

2015-05-01

Swine are susceptible to infection by both avian and human influenza viruses, and this feature is thought to contribute to novel reassortant influenza viruses. In this study, the influenza virus reassortment rate in swine and human cells was determined. Coinfection of swine cells with 2009 pandemic H1N1 virus (huH1N1) and an endemic swine H1N2 (A/swine/Illinois/02860/09) virus (swH1N2) resulted in a 23% reassortment rate that was independent of α2,3- or α2,6-sialic acid distribution on the cells. The reassortants had altered pathogenic phenotypes linked to introduction of the swine virus PA and neuraminidase (NA) into huH1N1. In mice, the huH1N1 PA and NA mediated increased MIP-2 expression early postinfection, resulting in substantial pulmonary neutrophilia with enhanced lung pathology and disease. The findings support the notion that swine are a mixing vessel for influenza virus reassortants independent of sialic acid distribution. These results show the potential for continued reassortment of the 2009 pandemic H1N1 virus with endemic swine viruses and for reassortants to have increased pathogenicity linked to the swine virus NA and PA genes which are associated with increased pulmonary neutrophil trafficking that is related to MIP-2 expression. Influenza A viruses can change rapidly via reassortment to create a novel virus, and reassortment can result in possible pandemics. Reassortments among subtypes from avian and human viruses led to the 1957 (H2N2 subtype) and 1968 (H3N2 subtype) human influenza pandemics. Recent analyses of circulating isolates have shown that multiple genes can be recombined from human, avian, and swine influenza viruses, leading to triple reassortants. Understanding the factors that can affect influenza A virus reassortment is needed for the establishment of disease intervention strategies that may reduce or preclude pandemics. The findings from this study show that swine cells provide a mixing vessel for influenza virus reassortment

Assessment of Mexican Arnica (Heterotheca inuloides Cass) and Rosemary (Rosmarinus officinalis) Extracts on Dopamine and Selected Biomarkers of Oxidative Stress in Stomach and Brain of Salmonella typhimurium Infected rats.

Science.gov (United States)

Guzmàn, David Calderón; Herrera, Maribel Ortiz; Brizuela, Norma Osnaya; Mejía, Gerardo Barragàn; García, Ernestina Hernàndez; Olguín, Hugo Juàrez; Peraza, Armando Valenzuela; Ruíz, Norma Labra; Del Angel, Daniel Santamaría

2017-01-01

The effects of some natural products on dopamine (DA) and 5-hydroxyindole acetic acid (5-HIAA) in brain of infected models are still unclear. The purpose of this study was to measure the effect of Mexican arnica/rosemary (MAR) water extract and oseltamivir on both biogenic amines and some oxidative biomarkers in the brain and stomach of young rats under infection condition. Female Wistar rats (weight 80 g) in the presence of MAR or absence (no-MAR) were treated as follows: group 1, buffer solution (controls); oseltamivir (100 mg/kg), group 2; culture of Salmonella typhimurium ( S.Typh ) (1 × 10 6 colony-forming units/rat) group 3; oseltamivir (100 mg/kg) + S.Typh (same dose) group 4. Drug and extracts were administered intraperitoneally every 24 h for 5 days, and S.Typh was given orally on days 1 and 3. On the fifth day, blood was collected to measure glucose and hemoglobin. The brains and stomachs were obtained to measure levels of DA, 5-HIAA, glutathione (GSH), TBARS, H 2 O 2 , and total ATPase activity using validated methods. DA levels increased in MAR group treated with oseltamivir alone but decreased in no-MAR group treated with oseltamivir plus S.Typh . 5-HIAA, GSH, and H 2 O 2 decreased in this last group, and ATPase activity increased in MAR group treated with oseltamivir plus S.Typh . TBARS (lipid peroxidation) increased in MAR group that received oseltamivir alone. Most of the biomarkers were not altered significantly in the stomach. MAR extract alters DA and metabolism of 5-HIAA in the brain of young animals infected. Antioxidant capacity may be involved in these effects. The purpose of this study was to measure the effect of Mexican arnica/rosemary water extract and oseltamivir on both biogenic amines and some oxidative biomarkers in the brain and stomach of young rats under infection condition. Results: Mexican arnica and rosemary extract alter dopamine and metabolism of 5-HIAA in the brain of young animals infected. Antioxidant capacity may be

The effects of residual platelets in plasma on plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays.

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Marlien Pieters

Full Text Available Due to controversial evidence in the literature pertaining to the activity of plasminogen activator inhibitor-1 in platelets, we examined the effects of residual platelets present in plasma (a potential pre-analytical variable on various plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays. Blood samples were collected from 151 individuals and centrifuged at 352 and 1500 g to obtain plasma with varying numbers of platelet. In a follow-up study, blood samples were collected from an additional 23 individuals, from whom platelet-poor (2000 g, platelet-containing (352 g and platelet-rich plasma (200 g were prepared and analysed as fresh-frozen and after five defrost-refreeze cycles (to determine the contribution of in vitro platelet degradation. Plasminogen activator inhibitor-1 activity, plasminogen activator inhibitor-1 antigen, tissue plasminogen activator/plasminogen activator inhibitor-1 complex, plasma clot lysis time, β-thromboglobulin and plasma platelet count were analysed. Platelet α-granule release (plasma β-thromboglobulin showed a significant association with plasminogen activator inhibitor-1 antigen levels but weak associations with plasminogen activator inhibitor-1 activity and a functional marker of fibrinolysis, clot lysis time. Upon dividing the study population into quartiles based on β-thromboglobulin levels, plasminogen activator inhibitor-1 antigen increased significantly across the quartiles while plasminogen activator inhibitor-1 activity and clot lysis time tended to increase in the 4th quartile only. In the follow-up study, plasma plasminogen activator inhibitor-1 antigen was also significantly influenced by platelet count in a concentration-dependent manner. Plasma plasminogen activator inhibitor-1 antigen levels increased further after complete platelet degradation. Residual platelets in plasma significantly influence plasma plasminogen activator inhibitor-1 antigen levels mainly

mTOR inhibitors alone and in combination with JAK2 inhibitors effectively inhibit cells of myeloproliferative neoplasms.

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Costanza Bogani

Full Text Available BACKGROUND: Dysregulated signaling of the JAK/STAT pathway is a common feature of chronic myeloproliferative neoplasms (MPN, usually associated with JAK2V617F mutation. Recent clinical trials with JAK2 inhibitors showed significant improvements in splenomegaly and constitutional symptoms in patients with myelofibrosis but meaningful molecular responses were not documented. Accordingly, there remains a need for exploring new treatment strategies of MPN. A potential additional target for treatment is represented by the PI3K/AKT/mammalian target of rapamycin (mTOR pathway that has been found constitutively activated in MPN cells; proof-of-evidence of efficacy of the mTOR inhibitor RAD001 has been obtained recently in a Phase I/II trial in patients with myelofibrosis. The aim of the study was to characterize the effects in vitro of mTOR inhibitors, used alone and in combination with JAK2 inhibitors, against MPN cells. FINDINGS: Mouse and human JAK2V617F mutated cell lines and primary hematopoietic progenitors from MPN patients were challenged with an allosteric (RAD001 and an ATP-competitive (PP242 mTOR inhibitor and two JAK2 inhibitors (AZD1480 and ruxolitinib. mTOR inhibitors effectively reduced proliferation and colony formation of cell lines through a slowed cell division mediated by changes in cell cycle transition to the S-phase. mTOR inhibitors also impaired the proliferation and prevented colony formation from MPN hematopoietic progenitors at doses significantly lower than healthy controls. JAK2 inhibitors produced similar antiproliferative effects in MPN cell lines and primary cells but were more potent inducers of apoptosis, as also supported by differential effects on cyclinD1, PIM1 and BcLxL expression levels. Co-treatment of mTOR inhibitor with JAK2 inhibitor resulted in synergistic activity against the proliferation of JAK2V617F mutated cell lines and significantly reduced erythropoietin-independent colony growth in patients with

Transforming growth factor-β: activation by neuraminidase and role in highly pathogenic H5N1 influenza pathogenesis.

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Christina M Carlson

2010-10-01

Full Text Available Transforming growth factor-beta (TGF-β, a multifunctional cytokine regulating several immunologic processes, is expressed by virtually all cells as a biologically inactive molecule termed latent TGF-β (LTGF-β. We have previously shown that TGF-β activity increases during influenza virus infection in mice and suggested that the neuraminidase (NA protein mediates this activation. In the current study, we determined the mechanism of activation of LTGF-β by NA from the influenza virus A/Gray Teal/Australia/2/1979 by mobility shift and enzyme inhibition assays. We also investigated whether exogenous TGF-β administered via a replication-deficient adenovirus vector provides protection from H5N1 influenza pathogenesis and whether depletion of TGF-β during virus infection increases morbidity in mice. We found that both the influenza and bacterial NA activate LTGF-β by removing sialic acid motifs from LTGF-β, each NA being specific for the sialic acid linkages cleaved. Further, NA likely activates LTGF-β primarily via its enzymatic activity, but proteases might also play a role in this process. Several influenza A virus subtypes (H1N1, H1N2, H3N2, H5N9, H6N1, and H7N3 except the highly pathogenic H5N1 strains activated LTGF-β in vitro and in vivo. Addition of exogenous TGF-β to H5N1 influenza virus-infected mice delayed mortality and reduced viral titers whereas neutralization of TGF-β during H5N1 and pandemic 2009 H1N1 infection increased morbidity. Together, these data show that microbe-associated NAs can directly activate LTGF-β and that TGF-β plays a pivotal role protecting the host from influenza pathogenesis.

Deliberate reduction of hemagglutinin and neuraminidase expression of influenza virus leads to an ultraprotective live vaccine in mice.

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Yang, Chen; Skiena, Steven; Futcher, Bruce; Mueller, Steffen; Wimmer, Eckard

2013-06-04

A long-held dogma posits that strong presentation to the immune system of the dominant influenza virus glycoprotein antigens neuraminidase (NA) and hemagglutinin (HA) is paramount for inducing protective immunity against influenza virus infection. We have deliberately violated this dogma by constructing a recombinant influenza virus strain of A/PR8/34 (H1N1) in which expression of NA and HA genes was suppressed. We down-regulated NA and HA expression by recoding the respective genes with suboptimal codon pair bias, thereby introducing hundreds of nucleotide changes while preserving their codon use and protein sequence. The variants PR8-NA(Min), PR8-HA(Min), and PR8-(NA+HA)(Min) (Min, minimal expression) were used to assess the contribution of reduced glycoprotein expression to growth in tissue culture and pathogenesis in BALB/c mice. All three variants proliferated in Madin-Darby canine kidney cells to nearly the degree as WT PR8. In mice, however, they expressed explicit attenuation phenotypes, as revealed by their LD50 values: PR8, 32 plaque-forming units (PFU); HA(Min), 1.7 × 10(3) PFU; NA(Min), 2.4 × 10(5) PFU; (NA+HA)(Min), ≥3.16 × 10(6) PFU. Remarkably, (NA+HA)(Min) was attenuated >100,000-fold, with NA(Min) the major contributor to attenuation. In vaccinated mice (NA+HA)(Min) was highly effective in providing long-lasting protective immunity against lethal WT challenge at a median protective dose (PD50) of 2.4 PFU. Moreover, at a PD50 of only 147 or 237, (NA+HA)(Min) conferred protection against heterologous lethal challenges with two mouse-adapted H3N2 viruses. We conclude that the suppression of HA and NA is a unique strategy in live vaccine development.

Chalcones as novel influenza A (H1N1) neuraminidase inhibitors from Glycyrrhiza inflata

DEFF Research Database (Denmark)

Dao, Trong Tuan; Nguyen, Phi Hung; Lee, Hong Sik

2011-01-01

The emergence of highly pathogenic influenza A virus strains, such as the new H1N1 swine influenza (novel influenza), represents a serious threat to global human health. During our course of an anti-influenza screening program on natural products, one new licochalcone G (1) and seven known (2-8) ...

Enabling the intestinal absorption of highly polar antiviral agents: ion-pair facilitated membrane permeation of zanamivir heptyl ester and guanidino oseltamivir.

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Miller, Jonathan M; Dahan, Arik; Gupta, Deepak; Varghese, Sheeba; Amidon, Gordon L

2010-08-02

Antiviral drugs often suffer from poor intestinal permeability, preventing their delivery via the oral route. The goal of this work was to enhance the intestinal absorption of the low-permeability antiviral agents zanamivir heptyl ester (ZHE) and guanidino oseltamivir (GO) utilizing an ion-pairing approach, as a critical step toward making them oral drugs. The counterion 1-hydroxy-2-naphthoic acid (HNAP) was utilized to enhance the lipophilicity and permeability of the highly polar drugs. HNAP substantially increased the log P of the drugs by up to 3.7 log units. Binding constants (K(11(aq))) of 388 M(-1) for ZHE-HNAP and 2.91 M(-1) for GO-HNAP were obtained by applying a quasi-equilibrium transport model to double-reciprocal plots of apparent octanol-buffer distribution coefficients versus HNAP concentration. HNAP enhanced the apparent permeability (P(app)) of both compounds across Caco-2 cell monolayers in a concentration-dependent manner, as substantial P(app) (0.8-3.0 x 10(-6) cm/s) was observed in the presence of 6-24 mM HNAP, whereas no detectable transport was observed without counterion. Consistent with a quasi-equilibrium transport model, a linear relationship with slope near 1 was obtained from a log-log plot of Caco-2 P(app) versus HNAP concentration, supporting the ion-pair mechanism behind the permeability enhancement. In the rat jejunal perfusion assay, the addition of HNAP failed to increase the effective permeability (P(eff)) of GO. However, the rat jejunal permeability of ZHE was significantly enhanced by the addition of HNAP in a concentration-dependent manner, from essentially zero without HNAP to 4.0 x 10(-5) cm/s with 10 mM HNAP, matching the P(eff) of the high-permeability standard metoprolol. The success of ZHE-HNAP was explained by its >100-fold stronger K(11(aq)) versus GO-HNAP, making ZHE-HNAP less prone to dissociation and ion-exchange with competing endogenous anions and able to remain intact during membrane permeation. Overall, this

Histone deacetylase inhibitors (HDACIs): multitargeted anticancer agents.

Science.gov (United States)

Ververis, Katherine; Hiong, Alison; Karagiannis, Tom C; Licciardi, Paul V

2013-01-01

Histone deacetylase (HDAC) inhibitors are an emerging class of therapeutics with potential as anticancer drugs. The rationale for developing HDAC inhibitors (and other chromatin-modifying agents) as anticancer therapies arose from the understanding that in addition to genetic mutations, epigenetic changes such as dysregulation of HDAC enzymes can alter phenotype and gene expression, disturb homeostasis, and contribute to neoplastic growth. The family of HDAC inhibitors is large and diverse. It includes a range of naturally occurring and synthetic compounds that differ in terms of structure, function, and specificity. HDAC inhibitors have multiple cell type-specific effects in vitro and in vivo, such as growth arrest, cell differentiation, and apoptosis in malignant cells. HDAC inhibitors have the potential to be used as monotherapies or in combination with other anticancer therapies. Currently, there are two HDAC inhibitors that have received approval from the US FDA for the treatment of cutaneous T-cell lymphoma: vorinostat (suberoylanilide hydroxamic acid, Zolinza) and depsipeptide (romidepsin, Istodax). More recently, depsipeptide has also gained FDA approval for the treatment of peripheral T-cell lymphoma. Many more clinical trials assessing the effects of various HDAC inhibitors on hematological and solid malignancies are currently being conducted. Despite the proven anticancer effects of particular HDAC inhibitors against certain cancers, many aspects of HDAC enzymes and HDAC inhibitors are still not fully understood. Increasing our understanding of the effects of HDAC inhibitors, their targets and mechanisms of action will be critical for the advancement of these drugs, especially to facilitate the rational design of HDAC inhibitors that are effective as antineoplastic agents. This review will discuss the use of HDAC inhibitors as multitargeted therapies for malignancy. Further, we outline the pharmacology and mechanisms of action of HDAC inhibitors while

Protection of chickens against H5N1 highly pathogenic avian influenza virus infection by live vaccination with infectious laryngotracheitis virus recombinants expressing H5 hemagglutinin and N1 neuraminidase.

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Pavlova, Sophia P; Veits, Jutta; Keil, Günther M; Mettenleiter, Thomas C; Fuchs, Walter

2009-01-29

Attenuated vaccine strains of the alphaherpesvirus causing infectious laryngotracheitis of chickens (ILTV, gallid herpesvirus 1) can be used for mass application. Previously, we showed that live virus vaccination with recombinant ILTV expressing hemagglutinin of highly pathogenic avian influenza viruses (HPAIV) protected chickens against ILT and fowl plague caused by HPAIV carrying the corresponding hemagglutinin subtypes [Lüschow D, Werner O, Mettenleiter TC, Fuchs W. Protection of chickens from lethal avian influenza A virus infection by live-virus vaccination with infectious laryngotracheitis virus recombinants expressing the hemagglutinin (H5) gene. Vaccine 2001;19(30):4249-59; Veits J, Lüschow D, Kindermann K, Werner O, Teifke JP, Mettenleiter TC, et al. Deletion of the non-essential UL0 gene of infectious laryngotracheitis (ILT) virus leads to attenuation in chickens, and UL0 mutants expressing influenza virus haemagglutinin (H7) protect against ILT and fowl plague. J Gen Virol 2003;84(12):3343-52]. However, protection against H5N1 HPAIV was not satisfactory. Therefore, a newly designed dUTPase-negative ILTV vector was used for rapid insertion of the H5-hemagglutinin, or N1-neuraminidase genes of a recent H5N1 HPAIV isolate. Compared to our previous constructs, protein expression was considerably enhanced by insertion of synthetic introns downstream of the human cytomegalovirus immediate-early promoter within the 5'-nontranslated region of the transgenes. Deletion of the viral dUTPase gene did not affect in vitro replication of the ILTV recombinants, but led to sufficient attenuation in vivo. After a single ocular immunization, all chickens developed H5- or N1-specific serum antibodies. Nevertheless, animals immunized with N1-ILTV died after subsequent H5N1 HPAIV challenge, although survival times were prolonged compared to non-vaccinated controls. In contrast, all chickens vaccinated with either H5-ILTV alone, or H5- and N1-ILTV simultaneously, survived

Identification of fermentation inhibitors in wood hydrolyzates and removal of inhibitors by ion exchange and liquid-liquid extraction

Science.gov (United States)

Luo, Caidian

1998-12-01

Common methods employed in the ethanol production from biomass consist of chemical or enzymatic degradation of biomass into sugars and then fermentation of sugars into ethanol or other chemicals. However, some degradation products severely inhibit the fermentation processes and substantially reduce the efficiency of ethanol production. How to remove inhibitors from the reaction product mixture and increase the production efficiency are critical in the commercialization of any processes of energy from biomass. The present study has investigated anion exchange and liquid-liquid extraction as potential methods for inhibitor removal. An analytical method has been developed to identify the fermentation inhibitors in a hydrolyzate. The majority of inhibitors present in hybrid poplar hydrolyzate have positively been identified. Ion exchange with weak basic Dowex-MWA-1 resin has been proved to be an effective mean to remove fermentation inhibitors from hybrid poplar hydrolyzate and significantly increase the fermentation productivity. Extraction with n-butanol might be a preferred way to remove inhibitors from wood hydrolyzates and improve the fermentability of sugars in the hydrolyzates. n-Butanol also removes some glucose, mannose and xylose from the hydrolyzate. Inhibitor identification reveals that lignin and sugar degradation compounds including both aromatic and aliphatic aldehydes and carboxylic acids formed in hydrolysis, plus fatty acids and other components from wood extractives are major fermentation inhibitors in Sacchromyces cerevisiae fermentation. There are 35 components identified as fermentation inhibitors. Among them, 4-hydroxy benzoic acid, 3,4-dihydroxy benzoic acid, syringic acid, syringaldehyde, and ferulic acid are among the most abundant aromatic inhibitors in hybrid poplar hydrolyzate. The conversion of aldehyde groups into carboxylic acid groups in the nitric acid catalyzed hydrolysis reduces the toxicity of the hydrolyzate. A wide spectrum of

Inga laurina trypsin inhibitor (ILTI) obstructs Spodoptera frugiperda trypsins expressed during adaptive mechanisms against plant protease inhibitors.

Science.gov (United States)

Machado, Suzy Wider; de Oliveira, Caio Fernando Ramalho; Zério, Neide Graciano; Parra, José Roberto Postali; Macedo, Maria Lígia Rodrigues

2017-08-01

Plant protease inhibitors (PIs) are elements of a common plant defense mechanism induced in response to herbivores. The fall armyworm, Spodoptera frugiperda, a highly polyphagous lepidopteran pest, responds to various PIs in its diet by expressing genes encoding trypsins. This raises the question of whether the PI-induced trypsins are also inhibited by other PIs, which we posed as the hypothesis that Inga laurina trypsin inhibitor (ILTI) inhibits PI-induced trypsins in S. frugiperda. In the process of testing our hypothesis, we compared its properties with those of selected PIs, soybean Kunitz trypsin inhibitor (SKTI), Inga vera trypsin inhibitor (IVTI), Adenanthera pavonina trypsin inhibitor (ApTI), and Entada acaciifolia trypsin inhibitor (EATI). We report that ILTI is more effective in inhibiting the induced S. frugiperda trypsins than SKTI and the other PIs, which supports our hypothesis. ILTI may be more appropriate than SKTI for studies regarding adaptive mechanisms to dietary PIs. © 2017 Wiley Periodicals, Inc.

Reduction rules for reset/inhibitor nets

NARCIS (Netherlands)

Verbeek, H.M.W.; Wynn, M.T.; Aalst, van der W.M.P.; Hofstede, ter A.H.M.

2010-01-01

Reset/inhibitor nets are Petri nets extended with reset arcs and inhibitor arcs. These extensions can be used to model cancellation and blocking. A reset arc allows a transition to remove all tokens from a certain place when the transition fires. An inhibitor arc can stop a transition from being

Histone deacetylase inhibitors (HDACIs: multitargeted anticancer agents

Directory of Open Access Journals (Sweden)

Ververis K

2013-02-01

Full Text Available Katherine Ververis,1 Alison Hiong,1 Tom C Karagiannis,1,* Paul V Licciardi2,*1Epigenomic Medicine, Alfred Medical Research and Education Precinct, 2Allergy and Immune Disorders, Murdoch Childrens Research Institute, Melbourne, VIC, Australia*These authors contributed equally to this workAbstract: Histone deacetylase (HDAC inhibitors are an emerging class of therapeutics with potential as anticancer drugs. The rationale for developing HDAC inhibitors (and other chromatin-modifying agents as anticancer therapies arose from the understanding that in addition to genetic mutations, epigenetic changes such as dysregulation of HDAC enzymes can alter phenotype and gene expression, disturb homeostasis, and contribute to neoplastic growth. The family of HDAC inhibitors is large and diverse. It includes a range of naturally occurring and synthetic compounds that differ in terms of structure, function, and specificity. HDAC inhibitors have multiple cell type-specific effects in vitro and in vivo, such as growth arrest, cell differentiation, and apoptosis in malignant cells. HDAC inhibitors have the potential to be used as monotherapies or in combination with other anticancer therapies. Currently, there are two HDAC inhibitors that have received approval from the US FDA for the treatment of cutaneous T-cell lymphoma: vorinostat (suberoylanilide hydroxamic acid, Zolinza and depsipeptide (romidepsin, Istodax. More recently, depsipeptide has also gained FDA approval for the treatment of peripheral T-cell lymphoma. Many more clinical trials assessing the effects of various HDAC inhibitors on hematological and solid malignancies are currently being conducted. Despite the proven anticancer effects of particular HDAC inhibitors against certain cancers, many aspects of HDAC enzymes and HDAC inhibitors are still not fully understood. Increasing our understanding of the effects of HDAC inhibitors, their targets and mechanisms of action will be critical for the

The low-pH stability discovered in neuraminidase of 1918 pandemic influenza A virus enhances virus replication.

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Tadanobu Takahashi

Full Text Available The "Spanish" pandemic influenza A virus, which killed more than 20 million worldwide in 1918-19, is one of the serious pathogens in recorded history. Characterization of the 1918 pandemic virus reconstructed by reverse genetics showed that PB1, hemagglutinin (HA, and neuraminidase (NA genes contributed to the viral replication and virulence of the 1918 pandemic influenza virus. However, the function of the NA gene has remained unknown. Here we show that the avian-like low-pH stability of sialidase activity discovered in the 1918 pandemic virus NA contributes to the viral replication efficiency. We found that deletion of Thr at position 435 or deletion of Gly at position 455 in the 1918 pandemic virus NA was related to the low-pH stability of the sialidase activity in the 1918 pandemic virus NA by comparison with the sequences of other human N1 NAs and sialidase activity of chimeric constructs. Both amino acids were located in or near the amino acid resides that were important for stabilization of the native tetramer structure in a low-pH condition like the N2 NAs of pandemic viruses that emerged in 1957 and 1968. Two reverse-genetic viruses were generated from a genetic background of A/WSN/33 (H1N1 that included low-pH-unstable N1 NA from A/USSR/92/77 (H1N1 and its counterpart N1 NA in which sialidase activity was converted to a low-pH-stable property by a deletion and substitutions of two amino acid residues at position 435 and 455 related to the low-pH stability of the sialidase activity in 1918 NA. The mutant virus that included "Spanish Flu"-like low-pH-stable NA showed remarkable replication in comparison with the mutant virus that included low-pH-unstable N1 NA. Our results suggest that the avian-like low-pH stability of sialidase activity in the 1918 pandemic virus NA contributes to the viral replication efficiency.

Histone Deacetylase Inhibitors as Anticancer Drugs.

Science.gov (United States)

Eckschlager, Tomas; Plch, Johana; Stiborova, Marie; Hrabeta, Jan

2017-07-01

Carcinogenesis cannot be explained only by genetic alterations, but also involves epigenetic processes. Modification of histones by acetylation plays a key role in epigenetic regulation of gene expression and is controlled by the balance between histone deacetylases (HDAC) and histone acetyltransferases (HAT). HDAC inhibitors induce cancer cell cycle arrest, differentiation and cell death, reduce angiogenesis and modulate immune response. Mechanisms of anticancer effects of HDAC inhibitors are not uniform; they may be different and depend on the cancer type, HDAC inhibitors, doses, etc. HDAC inhibitors seem to be promising anti-cancer drugs particularly in the combination with other anti-cancer drugs and/or radiotherapy. HDAC inhibitors vorinostat, romidepsin and belinostat have been approved for some T-cell lymphoma and panobinostat for multiple myeloma. Other HDAC inhibitors are in clinical trials for the treatment of hematological and solid malignancies. The results of such studies are promising but further larger studies are needed. Because of the reversibility of epigenetic changes during cancer development, the potency of epigenetic therapies seems to be of great importance. Here, we summarize the data on different classes of HDAC inhibitors, mechanisms of their actions and discuss novel results of preclinical and clinical studies, including the combination with other therapeutic modalities.

Histone Deacetylase Inhibitors as Anticancer Drugs

Directory of Open Access Journals (Sweden)

Tomas Eckschlager

2017-07-01

Full Text Available Carcinogenesis cannot be explained only by genetic alterations, but also involves epigenetic processes. Modification of histones by acetylation plays a key role in epigenetic regulation of gene expression and is controlled by the balance between histone deacetylases (HDAC and histone acetyltransferases (HAT. HDAC inhibitors induce cancer cell cycle arrest, differentiation and cell death, reduce angiogenesis and modulate immune response. Mechanisms of anticancer effects of HDAC inhibitors are not uniform; they may be different and depend on the cancer type, HDAC inhibitors, doses, etc. HDAC inhibitors seem to be promising anti-cancer drugs particularly in the combination with other anti-cancer drugs and/or radiotherapy. HDAC inhibitors vorinostat, romidepsin and belinostat have been approved for some T-cell lymphoma and panobinostat for multiple myeloma. Other HDAC inhibitors are in clinical trials for the treatment of hematological and solid malignancies. The results of such studies are promising but further larger studies are needed. Because of the reversibility of epigenetic changes during cancer development, the potency of epigenetic therapies seems to be of great importance. Here, we summarize the data on different classes of HDAC inhibitors, mechanisms of their actions and discuss novel results of preclinical and clinical studies, including the combination with other therapeutic modalities.

[ACE inhibitors and the kidney].

Science.gov (United States)

Hörl, W H

1996-01-01

Treatment with ACE inhibitors results in kidney protection due to reduction of systemic blood pressure, intraglomerular pressure, an antiproliferative effect, reduction of proteinuria and a lipid-lowering effect in proteinuric patients (secondary due to reduction of protein excretion). Elderly patients with diabetes melitus, coronary heart disease or peripheral vascular occlusion are at risk for deterioration of kidney function due to a high frequency of renal artery stenosis in these patients. In patients with renal insufficiency dose reduction of ACE inhibitors is necessary (exception: fosinopril) but more important is the risk for development of hyperkalemia. Patients at risk for renal artery stenosis and patients pretreated with diuretics should receive a low ACE inhibitor dosage initially ("start low - go slow"). For compliance reasons once daily ACE inhibitor dosage is recommended.

Natural inhibitors of tumor-associated proteases

International Nuclear Information System (INIS)

Magdolen, U.; Krol, J.; Sato, S.; Schmitt, M.; Magdolen, V.; Krueger, A.; Mueller, M.M.; Sperl, S.

2002-01-01

The turnover and remodelling of extracellular matrix (ECM) is an essential part of many normal biological processes including development, morphogenesis, and wound healing. ECM turnover also occurs in severe pathological situations like artherosclerosis, fibrosis, tumor invasion and metastasis. The major proteases involved in this turnover are serine proteases (especially the urokinase-type plasminogen activator/plasmin system), matrix metalloproteases (a family of about 20 zinc-dependent endopeptidases including collagenases, gelatinases, stromelysins, and membrane-type metalloproteases), and cysteine proteases. In vivo, the activity of these proteases is tightly regulated in the extracellular space by zymogen activation and/or controlled inhibition. In the present review, we give an overview on the structure and biochemical properties of important tumor-associated protease inhibitors such as plasminogen activator inhibitor type 1 and type 2 (PAI-1, PAI-2), tissue inhibitors of metalloproteinases (TIMP-1, -2, -3, and -4), and the cysteine protease inhibitor cystatin C. Interestingly, some of these inhibitors of tumor-associated proteases display multiple functions which rather promote than inhibit tumor progression, when the presence of inhibitors in the tumor tissue is not balanced. (author)

Aromatase inhibitors in pediatrics.

Science.gov (United States)

Wit, Jan M; Hero, Matti; Nunez, Susan B

2011-10-25

Aromatase, an enzyme located in the endoplasmic reticulum of estrogen-producing cells, catalyzes the rate-limiting step in the conversion of androgens to estrogens in many tissues. The clinical features of patients with defects in CYP19A1, the gene encoding aromatase, have revealed a major role for this enzyme in epiphyseal plate closure, which has promoted interest in the use of inhibitors of aromatase to improve adult height. The availability of the selective aromatase inhibitors letrozole and anastrozole--currently approved as adjuvant therapy for breast cancer--have stimulated off-label use of aromatase inhibitors in pediatrics for the following conditions: hyperestrogenism, such as aromatase excess syndrome, Peutz-Jeghers syndrome, McCune-Albright syndrome and functional follicular ovarian cysts; hyperandrogenism, for example, testotoxicosis (also known as familial male-limited precocious puberty) and congenital adrenal hyperplasia; pubertal gynecomastia; and short stature and/or pubertal delay in boys. Current data suggest that aromatase inhibitors are probably effective in the treatment of patients with aromatase excess syndrome or testotoxicosis, partially effective in Peutz-Jeghers and McCune-Albright syndrome, but probably ineffective in gynecomastia. Insufficient data are available in patients with congenital adrenal hyperplasia or functional ovarian cysts. Although aromatase inhibitors appear effective in increasing adult height of boys with short stature and/or pubertal delay, safety concerns, including vertebral deformities, a decrease in serum HDL cholesterol levels and increase of erythrocytosis, are reasons for caution.

[The primary structure of the alpha-amylase inhibitor Hoe 467A from Streptomyces tendae 4158. A new class of inhibitors].

Science.gov (United States)

Aschauer, H; Vértesy, L; Nesemann, G; Braunitzer, G

1983-10-01

The native or modified alpha-amylase inhibitor Hoe 467A - isolated from the culture medium of Streptomyces tendae 4158 - and overlapping peptides were degraded by the automatic Edman technique. The oxidized or aminoethylated or oxidized and maleoylated inhibitor was digested with trypsin and the native inhibitor with pepsin. Further digestion with Staphylococcus aureus proteinase was also carried out. After peptic digestion two cystin peptides were isolated, which allowed the establishment of the disulfide bonds. The alpha-amylase inhibitor is a polypeptid consisting of 74 amino-acid residues with a molecular mass of 7958 Da. The inhibitor is composed of all naturally occurring amino acids except methionine and phenylalanine and shows no sequence homology to known inhibitors. The clinical and pharmacological importance in respect to the inhibitors ability for inactivation of human salivary and pancreatic alpha-amylase is discussed. Especially the proteinase resistance of the inhibitor enables a clinical application in human (e.g. Diabetes mellitus) per os.

Squash inhibitor family of serine proteinases

International Nuclear Information System (INIS)

Otlewski, J.; Krowarsch, D.

1996-01-01

Squash inhibitors of serine proteinases form an uniform family of small proteins. They are built of 27-33 amino-acid residues and cross-linked with three disulfide bridges. The reactive site peptide bond (P1-P1') is between residue 5 (Lys, Arg or Leu) and 6 (always Ile). High resolution X-ray structures are available for two squash inhibitors complexed with trypsin. NMR solution structures have also been determined for free inhibitors. The major structural motif is a distorted, triple-stranded antiparallel beta-sheet. A similar folding motif has been recently found in a number of proteins, including: conotoxins from fish-hunting snails, carboxypeptidase inhibitor from potato, kalata B1 polypeptide, and in some growth factors (e.g. nerve growth factor, transforming growth factor β2, platelet-derived growth factor). Squash inhibitors are highly stable and rigid proteins. They inhibit a number of serine proteinases: trypsin, plasmin, kallikrein, blood clotting factors: X a and XII a , cathepsin G. The inhibition spectrum can be much broadened if specific amino-acid substitutions are introduced, especially at residues which contact proteinase. Squash inhibitors inhibit proteinases via the standard mechanism. According to the mechanism, inhibitors are substrates which exhibit at neutral pH a high k cat /K m index for hydrolysis and resynthesis of the reactive site, and a low value of the hydrolysis constant. (author)

Metal corrosion inhibitors and ecology

International Nuclear Information System (INIS)

Krasts, H.; Svarce, J.; Berge, B.

1999-01-01

The use of metal corrosion inhibitors in water is one of the cheapest method to protect metals against corrosion. However, the used inhibitors can come to surface water in the course of time and can become as source of environmental pollution. It is important to co-ordinate amount of substances in the elaborated inhibitors not only with demands for metal protection, but also with demands for quality of surface water and drinking water according to normative statements: 3.5 mg/l (as PO 4 ) for hexametaphosphate, tripolyphosphate and phosphonate; 40 mg/l (as SiO 2 for silicate, up to 1 mg/l for CU 2+ ; up to 5 mg/l for Zn 2+ ; up to 1 mg/l for B; up to 0.5 mg/l for Mo 2+ . The examples of the elaborated inhibitors are given. Many organic substances can be used as corrosion inhibitors, but there is shortage of standard methods for their analysis in water in Latvia. Removing of salt's deposits from boilers needs elaboration of a separate normative statement for dispersing waste water which content chloride at high concentration and heavy metals. (authors)

Surface-bound capsular polysaccharide of type Ia group B Streptococcus mediates C1 binding and activation of the classic complement pathway

International Nuclear Information System (INIS)

Levy, N.J.; Kasper, D.L.

1986-01-01

The role of surface-bound type Ia group B Streptococcus (GBS) capsular polysaccharide in anti-body-independent binding of C1 and activation of the classic component pathway was investigated. In a radiolabeled bacterial-polymorphonuclear leukocyte (PMN) association assay, a measure of bacterial opsonization, preincubation of 3 H-type Ia GBS with purified F(ab') 2 to the organism blocked the association of the bacteria with PMN', and the inhibitory effect was dose dependent. The specificity of F(ab') 2 blocking was shown after adsorption of F(ab') 2 with type Ia polysaccharide-sensitized erythrocytes. Polysaccharide-adsorbed F(ab') 2 had a 70% decrease in ability to block the association of bacteria with PMN. Neuraminidase digestion removed 80% of the terminal sialic acid residues from the native polysaccharide. These neuraminidase-digested organisms had a 72% decrease in binding and transfer of purified C1 compared with non-enzyme-treated organisms. Type Ia capsular polysaccharide bound to sheep erythrocytes promoted classic complement pathway-mediated hemolysis of the cells. The role of C1 inhibitor (INH) in modulation of C1 activation by the organisms was investigated. The possibility existed that the C1 INH could be bound by the bacteria, allowing C1 activation to occur in the fluid phase. The inhibitor was purified from human serum, and its activity was measured before and after incubation with type Ia GBS. The organisms had no effect on C1 INH activity. Thus surface-bound capsular polysacchardie of type Ia GBS mediates C1 binding and classic pathway activation, and this does not involve the C1 INH

Invertase proteinaceous inhibitor of Cyphomandra betacea Sendt fruits.

Science.gov (United States)

Ordóñez, R M; Isla, M I; Vattuone, M A; Sampietro, A R

2000-01-01

This work describes a new invertase proteinaceous inhibitor from Cyphomandra betacea Sendt. (tomate de arbol) fruits. The proteinaceous inhibitor was isolated and purified from a cell wall preparation. The pH stability, kinetics of the inhibition of the C. betacea invertase, inhibition of several higher plant invertases and lectin nature of the inhibitor were studied. The inhibitor structure involves a single polypeptide (Mr = 19000), as shown by gel filtration and SDS-PAGE determinations. N-terminal aminoacid sequence was determined. The properties and some structural features of the inhibitor are compared with the proteinaceous inhibitors from several plant species (Beta vulgaris L., Ipomoea batatas L. and Lycopersicon esculentum Mill.). All these inhibitors share lectinic properties, some common epitopes, some aminoacid sequences and a certain lack of specificity towards invertases of different species, genera and even plant family. In consequence, the inhibitors appear to belong to the same lectin family. It is now known that some lectins are part of the defence mechanism of higher plants against fungi and bacteria and this is a probable role of the proteinaceous inhibitors.

Cathepsin D inhibitors

Directory of Open Access Journals (Sweden)

M. Gacko

2007-11-01

Full Text Available Inhibitors of cathepsin D belong to chemical compounds that estrify carboxyl groups of the Asp33 and Asp231residues of its catalytic site, penta-peptides containing statin, i.e. the amino acid similar in structure to the tetraedric indirectproduct, and polypeptides found in the spare organs of many plants and forming permanent noncovalent complexes withcathepsin. Cathepsin D activity is also inhibited by alpha2-macroglobulin and antibodies directed against this enzyme.Methods used to determine the activity and concentration of these inhibitors and their analytical, preparative and therapeuticapplications are discussed.

Development of Radiosensitizer using farnesyltransferase inhibitors

Energy Technology Data Exchange (ETDEWEB)

Lim, Jong Seok; Choe, Yong Kyung; Han, Mi Young; Kim, Kwang Dong [Korea Research Institute of Bioscience and Biotechnology, Taejon (Korea)

1999-03-01

We selected some compounds that were reported to have an activity of farneyltransferase inhibitor and tested the hypothesis that they might be used to radiosensitize cells transformed by ras oncogenes. The inhibition of ras processing using some, but not all, inhibitors resulted in higher levels of cell death after {gamma}-irradiation and increased radiosensitivity in H-ras-transformed NIH3T3 cells and MCF-10A human tumor cells. They did not induce additional cell death in control cells that doe not have ras mutation. Furthermore, the treatment of inhibitors alone induced a weak G0/G1 block, whereas inhibitors in combination with {gamma}-irradiation induced an additional enrichment in the G2/M phase of the cell cycle that typically represents irradiation-induced growth arrest. At present, the underling mechanism by which the farnesylltransferase inhibitors exert radiosensitizing effect is not known. In summary, our results suggest and lead to the possibility that some of farnesylation inhibitors may prove clinically useful not only as antitumor agents, but also radiosensitizers of tumors whose growth is dependent on ras function. (author). 15 refs., 10 figs., 4 tabs.

[Syk inhibitors].

Science.gov (United States)

Kimura, Yukihiro; Chihara, Kazuyasu; Takeuchi, Kenji; Sada, Kiyonao

2013-07-01

Non-receptor type of protein-tyrosine kinase Syk (spleen tyrosine kinase) was isolated in the University of Fukui in 1991. Syk is known to be essential for the various physiological functions, especially in hematopoietic lineage cells. Moreover, ectopic expression of Syk by epigenetic changes is reported to cause retinoblastoma. Recently, novel Syk inhibitors were developed and its usefulness has been evaluated in the treatment of allergic rhinitis, rheumatoid arthritis, and idiopathic thrombocytopenic purpura. In this review, we will summarize the history, structure, and function of Syk, and then describe the novel Syk inhibitors and their current status. Furthermore, we will introduce our findings of the adaptor protein 3BP2 (c-Abl SH3 domain-binding protein-2), as a novel target of Syk.

Organization of the gene coding for human protein C inhibitor (plasminogen activator inhibitor-3). Assignment of the gene to chromosome 14

NARCIS (Netherlands)

Meijers, J. C.; Chung, D. W.

1991-01-01

Protein C inhibitor (plasminogen activator inhibitor-3) is a plasma glycoprotein and a member of the serine proteinase inhibitor superfamily. In the present study, the human gene for protein C inhibitor was isolated and characterized from three independent phage that contained overlapping inserts

Inhibitor chymotrypsynowy nasion wiechliny łąkowej (Poa pratensis [Chymotrypsin inhibitor from Poa pratensis seeds

Directory of Open Access Journals (Sweden)

I. Lorenc-Kubis

2015-01-01

Full Text Available A chymotrypsin inhibitor was isolated from Poa pratensis seeds. The inhibitor showed also antytriptic activity. It is a termostable protein, soluble in water, sodium chloride, but insoluble in 5% trichloracetic acid and 0.15 M sulphosalicylic acid.

A comparison of effects of DPP-4 inhibitor and SGLT2 inhibitor on lipid profile in patients with type 2 diabetes.

Science.gov (United States)

Cha, Seon-Ah; Park, Yong-Moon; Yun, Jae-Seung; Lim, Tae-Seok; Song, Ki-Ho; Yoo, Ki-Dong; Ahn, Yu-Bae; Ko, Seung-Hyun

2017-04-13

Previous studies suggest that dipeptidyl peptidase-4 (DPP-4) inhibitors and sodium glucose cotransporter 2 (SGLT2) inhibitors have different effects on the lipid profile in patients with type 2 diabetes. We investigated the effects of DPP-4 inhibitors and SGLT2 inhibitors on the lipid profile in patients with type 2 diabetes. From January 2013 to December 2015, a total of 228 patients with type 2 diabetes who were receiving a DPP-4 inhibitor or SGLT2 inhibitor as add-on therapy to metformin and/or a sulfonylurea were consecutively enrolled. We compared the effects of DPP-4 inhibitors and SGLT2 inhibitors on the lipid profile at baseline and after 24 weeks of treatment. To compare lipid parameters between the two groups, we used the analysis of covariance (ANCOVA). A total of 184 patients completed follow-up (mean age: 53.1 ± 6.9 years, mean duration of diabetes: 7.1 ± 5.7 years). From baseline to 24 weeks, HDL-cholesterol (HDL-C) levels were increased by 0.5 (95% CI, -0.9 to 2.0) mg/dl with a DPP-4 inhibitor and by 5.1 (95% CI, 3.0 to 7.1) mg/dl with an SGLT2 inhibitor (p = 0.001). LDL-cholesterol (LDL-C) levels were reduced by 8.4 (95% CI, -14.0 to -2.8) mg/dl with a DPP-4 inhibitor, but increased by 1.3 (95% CI, -5.1 to 7.6) mg/dl with an SGLT2 inhibitor (p = 0.046). There was no significant difference in the mean hemoglobin A1c (8.3 ± 1.1 vs. 8.0 ± 0.9%, p = 0.110) and in the change of total cholesterol (TC) (p = 0.836), triglyceride (TG) (p = 0.867), apolipoprotein A (p = 0.726), apolipoprotein B (p = 0.660), and lipoprotein (a) (p = 0.991) between the DPP-4 inhibitor and the SGLT2 inhibitor. The SGLT2 inhibitor was associated with a significant increase in HDL-C and LDL-C after 24 weeks of SGLT2 inhibitor treatment in patients with type 2 diabetes compared with those with DPP-4 inhibitor treatment in this study. This study was conducted by retrospective medical record review.

Tyrosine kinase inhibitors: Multi-targeted or single-targeted?

Science.gov (United States)

Broekman, Fleur; Giovannetti, Elisa; Peters, Godefridus J

2011-02-10

Since in most tumors multiple signaling pathways are involved, many of the inhibitors in clinical development are designed to affect a wide range of targeted kinases. The most important tyrosine kinase families in the development of tyrosine kinase inhibitors are the ABL, SCR, platelet derived growth factor, vascular endothelial growth factor receptor and epidermal growth factor receptor families. Both multi-kinase inhibitors and single-kinase inhibitors have advantages and disadvantages, which are related to potential resistance mechanisms, pharmacokinetics, selectivity and tumor environment. In different malignancies various tyrosine kinases are mutated or overexpressed and several resistance mechanisms exist. Pharmacokinetics is influenced by interindividual differences and differs for two single targeted inhibitors or between patients treated by the same tyrosine kinase inhibitor. Different tyrosine kinase inhibitors have various mechanisms to achieve selectivity, while differences in gene expression exist between tumor and stromal cells. Considering these aspects, one type of inhibitor can generally not be preferred above the other, but will depend on the specific genetic constitution of the patient and the tumor, allowing personalized therapy. The most effective way of cancer treatment by using tyrosine kinase inhibitors is to consider each patient/tumor individually and to determine the strategy that specifically targets the consequences of altered (epi)genetics of the tumor. This strategy might result in treatment by a single multi kinase inhibitor for one patient, but in treatment by a couple of single kinase inhibitors for other patients.

Evaluation of Encapsulated Inhibitor for Autonomous Corrosion Protection

Science.gov (United States)

Johnsey, M. N.; Li, W.; Buhrow, J. W.; Calle, L. M.; Pearman, B. P.; Zhang, X.

2015-01-01

This work concerns the development of smart coating technologies based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of corrosion inhibitors into coating which provides protection through corrosion-controlled release of these inhibitors.One critical aspect of a corrosion protective smart coating is the selection of corrosion inhibitor for encapsulation and comparison of the inhibitor function before and after encapsulation. For this purpose, a systematic approach is being used to evaluate free and encapsulated corrosion inhibitors by salt immersion. Visual, optical microscope, and Scanning Electron Microscope (with low-angle backscatter electron detector) are used to evaluate these inhibitors. It has been found that the combination of different characterization tools provide an effective method for evaluation of early stage localized corrosion and the effectiveness of corrosion inhibitors.

Biological abatement of cellulase inhibitors

Science.gov (United States)

Bio-abatement uses a fungus to metabolize and remove fermentation inhibitors. To determine whether bio-abatement could alleviate enzyme inhibitor effects observed in biomass liquors after pretreatment, corn stover at 10% (w/v) solids was pretreated with either dilute acid or liquid hot water. The ...

Use of selective-serotonin reuptake inhibitors and platelet aggregation inhibitors among individuals with co-occurring atherosclerotic cardiovascular disease and depression or anxiety

Directory of Open Access Journals (Sweden)

J Douglas Thornton

2016-12-01

Full Text Available Objective: Medications commonly used to treat heart disease, anxiety, and depression can interact resulting in an increased risk of bleeding, warranting a cautious approach in medical decision making. This retrospective, descriptive study examined the prevalence and the factors associated with the use of both selective-serotonin reuptake inhibitor and platelet aggregation inhibitor among individuals with co-occurring atherosclerotic cardiovascular disease and anxiety or depression. Methods: Respondents aged 22 years and older, alive throughout the study period, and diagnosed with co-occurring atherosclerotic cardiovascular disease and anxiety or depression (n = 1507 in years 2007 through 2013 of the Medical Expenditures Panel Survey were included. The use of treatment was grouped as follows: selective-serotonin reuptake inhibitor and platelet aggregation inhibitor, selective-serotonin reuptake inhibitor or platelet aggregation inhibitor, and neither selective-serotonin reuptake inhibitor nor platelet aggregation inhibitor. Results: Overall, 16.5% used both selective-serotonin reuptake inhibitor and platelet aggregation inhibitor, 61.2% used selective-serotonin reuptake inhibitor or platelet aggregation inhibitor, and 22.3% used neither selective-serotonin reuptake inhibitor nor platelet aggregation inhibitor. Respondents aged over 65 years (adjusted odds ratio = 1.93 (95% confidence interval = 1.08–3.45 and having a diagnosis of diabetes (adjusted odds ratio = 1.63 (95% confidence interval = 1.15–2.31 and hypertension (adjusted odds ratio = 1.84 (95% confidence interval = 1.04–3.27 were more likely to be prescribed the combination. Conclusion: The drug interaction was prevalent in patients who are already at higher risk of health disparities and worse outcomes thus requiring vigilant evaluation.

Emerging Corrosion Inhibitors for Interfacial Coating

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Mona Taghavikish

2017-12-01

Full Text Available Corrosion is a deterioration of a metal due to reaction with environment. The use of corrosion inhibitors is one of the most effective ways of protecting metal surfaces against corrosion. Their effectiveness is related to the chemical composition, their molecular structures and affinities for adsorption on the metal surface. This review focuses on the potential of ionic liquid, polyionic liquid (PIL and graphene as promising corrosion inhibitors in emerging coatings due to their remarkable properties and various embedment or fabrication strategies. The review begins with a precise description of the synthesis, characterization and structure-property-performance relationship of such inhibitors for anti-corrosion coatings. It establishes a platform for the formation of new generation of PIL based coatings and shows that PIL corrosion inhibitors with various heteroatoms in different form can be employed for corrosion protection with higher barrier properties and protection of metal surface. However, such study is still in its infancy and there is significant scope to further develop new structures of PIL based corrosion inhibitors and coatings and study their behaviour in protection of metals. Besides, it is identified that the combination of ionic liquid, PIL and graphene could possibly contribute to the development of the ultimate corrosion inhibitor based coating.

Structural Mechanism of the Pan-BCR-ABL Inhibitor Ponatinib (AP24534): Lessons for Overcoming Kinase Inhibitor Resistance

Energy Technology Data Exchange (ETDEWEB)

Zhou, Tianjun; Commodore, Lois; Huang, Wei-Sheng; Wang, Yihan; Thomas, Mathew; Keats, Jeff; Xu, Qihong; Rivera, Victor M.; Shakespeare, William C.; Clackson, Tim; Dalgarno, David C.; Zhu, Xiaotian (ARIAD)

2012-01-20

The BCR-ABL inhibitor imatinib has revolutionized the treatment of chronic myeloid leukemia. However, drug resistance caused by kinase domain mutations has necessitated the development of new mutation-resistant inhibitors, most recently against the T315I gatekeeper residue mutation. Ponatinib (AP24534) inhibits both native and mutant BCR-ABL, including T315I, acting as a pan-BCR-ABL inhibitor. Here, we undertook a combined crystallographic and structure-activity relationship analysis on ponatinib to understand this unique profile. While the ethynyl linker is a key inhibitor functionality that interacts with the gatekeeper, virtually all other components of ponatinib play an essential role in its T315I inhibitory activity. The extensive network of optimized molecular contacts found in the DFG-out binding mode leads to high potency and renders binding less susceptible to disruption by single point mutations. The inhibitory mechanism exemplified by ponatinib may have broad relevance to designing inhibitors against other kinases with mutated gatekeeper residues.

Laura: Soybean variety lacking Kunitz trypsin inhibitor

Directory of Open Access Journals (Sweden)

Srebrić Mirjana

2010-01-01

Full Text Available Grain of conventional soybean varieties requires heat processing to break down trypsin inhibitor's activity before using as food or animal feed. At the same time, protein denaturation and other qualitative changes occur in soybean grain, especially if the temperature of heating is not controlled. Two types of trypsin inhibitor were found in soybean grain the Kunitz trypsin inhibitor and the Bowman-Birk inhibitor. Mature grain of soybean Laura is lacking Kunitz trypsin inhibitor. Grain yield of variety Laura is equal to high yielding varieties from the maturity group I, where it belongs. Lacking of Kunitz-trypsin inhibitor makes soybean grain suitable for direct feeding in adult non ruminant animals without previous thermal processing. Grain of variety Laura can be processed for a shorter period of time than conventional soybeans. This way we save energy, and preserve valuable nutritional composition of soybean grain, which is of interest in industrial processing.

Corrosion inhibitors. Manufacture and technology

International Nuclear Information System (INIS)

Ranney, M.W.

1976-01-01

Detailed information is presented relating to corrosion inhibitors. Areas covered include: cooling water, boilers and water supply plants; oil well and refinery operations; fuel and lubricant additives for automotive use; hydraulic fluids and machine tool lubes; grease compositions; metal surface treatments and coatings; and general processes for corrosion inhibitors

Potential physiological role of plant glycosidase inhibitors

DEFF Research Database (Denmark)

Bellincampi, D.; Carmadella, L.; Delcour, J.A.

2004-01-01

Carbohydrate-active enzymes including glycosidases, transglycosidases, glycosyltransferases, polysaccharide lyases and carbohydrate esterases are responsible for the enzymatic processing of carbohydrates in plants. A number of carbohydrate-active enzymes are produced by microbial pathogens...... and insects responsible of severe crop losses. Plants have evolved proteinaceous inhibitors to modulate the activity of several of these enzymes. The continuing discovery of new inhibitors indicates that this research area is still unexplored and may lead to new exciting developments. To date, the role...... of the inhibitors is not completely understood. Here we review recent results obtained on the best characterised inhibitors, pointing to their possible biological role in vivo. Results recently obtained with plant transformation technology indicate that this class of inhibitors has potential biotechnological...

SGLT2 Inhibitors May Predispose to Ketoacidosis.

Science.gov (United States)

Taylor, Simeon I; Blau, Jenny E; Rother, Kristina I

2015-08-01

Sodium glucose cotransporter 2 (SGLT2) inhibitors are antidiabetic drugs that increase urinary excretion of glucose, thereby improving glycemic control and promoting weight loss. Since approval of the first-in-class drug in 2013, data have emerged suggesting that these drugs increase the risk of diabetic ketoacidosis. In May 2015, the Food and Drug Administration issued a warning that SGLT2 inhibitors may lead to ketoacidosis. Using PubMed and Google, we conducted Boolean searches including terms related to ketone bodies or ketoacidosis with terms for SGLT2 inhibitors or phlorizin. Priority was assigned to publications that shed light on molecular mechanisms whereby SGLT2 inhibitors could affect ketone body metabolism. SGLT2 inhibitors trigger multiple mechanisms that could predispose to diabetic ketoacidosis. When SGLT2 inhibitors are combined with insulin, it is often necessary to decrease the insulin dose to avoid hypoglycemia. The lower dose of insulin may be insufficient to suppress lipolysis and ketogenesis. Furthermore, SGLT2 is expressed in pancreatic α-cells, and SGLT2 inhibitors promote glucagon secretion. Finally, phlorizin, a nonselective inhibitor of SGLT family transporters decreases urinary excretion of ketone bodies. A decrease in the renal clearance of ketone bodies could also increase the plasma ketone body levels. Based on the physiology of SGLT2 and the pharmacology of SGLT2 inhibitors, there are several biologically plausible mechanisms whereby this class of drugs has the potential to increase the risk of developing diabetic ketoacidosis. Future research should be directed toward identifying which patients are at greatest risk for this side effect and also to optimizing pharmacotherapy to minimize the risk to patients.

Inhibitory Effects of Respiration Inhibitors on Aflatoxin Production

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Shohei Sakuda

2014-03-01

Full Text Available Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control.

Inhibitory Effects of Respiration Inhibitors on Aflatoxin Production

Science.gov (United States)

Sakuda, Shohei; Prabowo, Diyan Febri; Takagi, Keiko; Shiomi, Kazuro; Mori, Mihoko; Ōmura, Satoshi; Nagasawa, Hiromichi

2014-01-01

Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A) inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III) and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control. PMID:24674936

Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs)

Science.gov (United States)

Serotonin and norepinephrine reuptake inhibitors (SNRIs) Antidepressant SNRIs help relieve depression symptoms, such as irritability and sadness, ... effects they may cause. By Mayo Clinic Staff Serotonin and norepinephrine reuptake inhibitors (SNRIs) are a class ...

Novel orally bioavailable EZH1/2 dual inhibitors with greater antitumor efficacy than an EZH2 selective inhibitor.

Science.gov (United States)

Honma, Daisuke; Kanno, Osamu; Watanabe, Jun; Kinoshita, Junzo; Hirasawa, Makoto; Nosaka, Emi; Shiroishi, Machiko; Takizawa, Takeshi; Yasumatsu, Isao; Horiuchi, Takao; Nakao, Akira; Suzuki, Keisuke; Yamasaki, Tomonori; Nakajima, Katsuyoshi; Hayakawa, Miho; Yamazaki, Takanori; Yadav, Ajay Singh; Adachi, Nobuaki

2017-10-01

Polycomb repressive complex 2 (PRC2) methylates histone H3 lysine 27 and represses gene expression to regulate cell proliferation and differentiation. Enhancer of zeste homolog 2 (EZH2) or its close homolog EZH1 functions as a catalytic subunit of PRC2, so there are two PRC2 complexes containing either EZH2 or EZH1. Tumorigenic functions of EZH2 and its synthetic lethality with some subunits of SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complexes have been observed. However, little is known about the function of EZH1 in tumorigenesis. Herein, we developed novel, orally bioavailable EZH1/2 dual inhibitors that strongly and selectively inhibited methyltransferase activity of both EZH2 and EZH1. EZH1/2 dual inhibitors suppressed trimethylation of histone H3 lysine 27 in cells more than EZH2 selective inhibitors. They also showed greater antitumor efficacy than EZH2 selective inhibitor in vitro and in vivo against diffuse large B-cell lymphoma cells harboring gain-of-function mutation in EZH2. A hematological cancer panel assay indicated that EZH1/2 dual inhibitor has efficacy against some lymphomas, multiple myeloma, and leukemia with fusion genes such as MLL-AF9, MLL-AF4, and AML1-ETO. A solid cancer panel assay demonstrated that some cancer cell lines are sensitive to EZH1/2 dual inhibitor in vitro and in vivo. No clear correlation was detected between sensitivity to EZH1/2 dual inhibitor and SWI/SNF mutations, with a few exceptions. Severe toxicity was not seen in rats treated with EZH1/2 dual inhibitor for 14 days at drug levels higher than those used in the antitumor study. Our results indicate the possibility of EZH1/2 dual inhibitors for clinical applications. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Structure-Based Search for New Inhibitors of Cholinesterases

Directory of Open Access Journals (Sweden)

Barbara Malawska

2013-03-01

Full Text Available Cholinesterases are important biological targets responsible for regulation of cholinergic transmission, and their inhibitors are used for the treatment of Alzheimer’s disease. To design new cholinesterase inhibitors, of different structure-based design strategies was followed, including the modification of compounds from a previously developed library and a fragment-based design approach. This led to the selection of heterodimeric structures as potential inhibitors. Synthesis and biological evaluation of selected candidates confirmed that the designed compounds were acetylcholinesterase inhibitors with IC50 values in the mid-nanomolar to low micromolar range, and some of them were also butyrylcholinesterase inhibitors.

Biological abatement of cellulase inhibitors.

Science.gov (United States)

Cao, Guangli; Ximenes, Eduardo; Nichols, Nancy N; Zhang, Leyu; Ladisch, Michael

2013-10-01

Removal of enzyme inhibitors released during lignocellulose pretreatment is essential for economically feasible biofuel production. We tested bio-abatement to mitigate enzyme inhibitor effects observed in corn stover liquors after pretreatment with either dilute acid or liquid hot water at 10% (w/v) solids. Bio-abatement of liquors was followed by enzymatic hydrolysis of cellulose. To distinguish between inhibitor effects on enzymes and recalcitrance of the substrate, pretreated corn stover solids were removed and replaced with 1% (w/v) Solka Floc. Cellulose conversion in the presence of bio-abated liquors from dilute acid pretreatment was 8.6% (0.1x enzyme) and 16% (1x enzyme) higher than control (non-abated) samples. In the presence of bio-abated liquor from liquid hot water pretreated corn stover, 10% (0.1x enzyme) and 13% (1x enzyme) higher cellulose conversion was obtained compared to control. Bio-abatement yielded improved enzyme hydrolysis in the same range as that obtained using a chemical (overliming) method for mitigating inhibitors. Copyright © 2013 Elsevier Ltd. All rights reserved.

Phosphodiesterase inhibitors in clinical urology.

Science.gov (United States)

Ückert, Stefan; Kuczyk, Markus A; Oelke, Matthias

2013-05-01

To date, benign diseases of the male and female lower urinary and genital tract, such as erectile dysfunction, bladder overactivity, lower urinary tract symptomatology secondary to benign prostatic hyperplasia and symptoms of female sexual dysfunction (including arousal and orgasmic disorders), can be therapeutically approached by influencing the function of the smooth musculature of the respective tissues. The use of isoenzyme-selective phosphodiesterase (PDE) inhibitors is considered a great opportunity to treat various diseases of the human urogenital tract. PDE inhibitors, in particular the PDE5 (cyclic GMP PDE) inhibitors avanafil, lodenafil, sildenafil, tadalafil, udenafil and vardenafil, are regarded as efficacious, having a fast onset of drug action and an improved effect-to-adverse event ratio, combining a high response rate with the advantage of an on-demand intake. The purpose of this review is to summarize recent as well as potential future indications, namely, erectile dysfunction, Peyronie's disease, overactive bladder, urinary stone disease, lower urinary tract symptomatology secondary to benign prostatic hyperplasia and premature ejaculation, for the use of PDE inhibitors in clinical urology.

F8 haplotype and inhibitor risk: results from the Hemophilia Inhibitor Genetics Study (HIGS) Combined Cohort

Science.gov (United States)

Schwarz, John; Astermark, Jan; Menius, Erika D.; Carrington, Mary; Donfield, Sharyne M.; Gomperts, Edward D.; Nelson, George W.; Oldenburg, Johannes; Pavlova, Anna; Shapiro, Amy D.; Winkler, Cheryl A.; Berntorp, Erik

2012-01-01

Background Ancestral background, specifically African descent, confers higher risk for development of inhibitory antibodies to factor VIII (FVIII) in hemophilia A. It has been suggested that differences in the distribution of factor VIII gene (F8) haplotypes, and mismatch between endogenous F8 haplotypes and those comprising products used for treatment could contribute to risk. Design and Methods Data from the HIGS Combined Cohort were used to determine the association between F8 haplotype 3 (H3) vs. haplotypes 1 and 2 (H1+H2) and inhibitor risk among individuals of genetically-determined African descent. Other variables known to affect inhibitor risk including type of F8 mutation and HLA were included in the analysis. A second research question regarding risk related to mismatch in endogenous F8 haplotype and recombinant FVIII products used for treatment was addressed. Results H3 was associated with higher inhibitor risk among those genetically-identified (N=49) as of African ancestry, but the association did not remain significant after adjustment for F8 mutation type and the HLA variables. Among subjects of all racial ancestries enrolled in HIGS who reported early use of recombinant products (N=223), mismatch in endogenous haplotype and the FVIII proteins constituting the products used did not confer greater risk for inhibitor development. Conclusion H3 was not an independent predictor of inhibitor risk. Further, our findings did not support a higher risk of inhibitors in the presence of a haplotype mismatch between the FVIII molecule infused and that of the individual. PMID:22958194

Monoamine depletion by reuptake inhibitors

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Hinz M

2011-10-01

Full Text Available Marty Hinz1, Alvin Stein2, Thomas Uncini31Clinical Research, NeuroResearch Clinics Inc, Cape Coral, FL; 2Stein Orthopedic Associates, Plantation, FL; 3DBS Labs Inc, Duluth, MN, USABackground: Disagreement exists regarding the etiology of cessation of the observed clinical results with administration of reuptake inhibitors. Traditionally, when drug effects wane, it is known as tachyphylaxis. With reuptake inhibitors, the placebo effect is significantly greater than the drug effect in the treatment of depression and attention deficit hyperactivity disorder, leading some to assert that waning of drug effects is placebo relapse, not tachyphylaxis.Methods: Two groups were retrospectively evaluated. Group 1 was composed of subjects with depression and Group 2 was composed of bariatric subjects treated with reuptake inhibitors for appetite suppression.Results: In Group 1, 200 subjects with depression were treated with citalopram 20 mg per day. A total of 46.5% (n = 93 achieved relief of symptoms (Hamilton-D rating score ≤ 7, of whom 37 (39.8% of whom experienced recurrence of depression symptoms, at which point an amino acid precursor formula was started. Within 1–5 days, 97.3% (n = 36 experienced relief of depression symptoms. In Group 2, 220 subjects were treated with phentermine 30 mg in the morning and citalopram 20 mg at 4 pm. In this group, 90.0% (n = 198 achieved adequate appetite suppression. The appetite suppression ceased in all 198 subjects within 4–48 days. Administration of an amino acid precursor formula restored appetite suppression in 98.5% (n = 195 of subjects within 1–5 days.Conclusion: Reuptake inhibitors do not increase the total number of monoamine molecules in the central nervous system. Their mechanism of action facilitates redistribution of monoamines from one place to another. In the process, conditions are induced that facilitate depletion of monoamines. The "reuptake inhibitor monoamine depletion theory" of this paper

Theoretical study on the interaction of pyrrolopyrimidine derivatives as LIMK2 inhibitors: insight into structure-based inhibitor design.

Science.gov (United States)

Shen, Mingyun; Zhou, Shunye; Li, Youyong; Li, Dan; Hou, Tingjun

2013-10-01

LIM kinases (LIMKs), downstream of Rho-associated protein kinases (ROCKs) and p21-activated protein kinases (PAKs), are shown to be promising targets for the treatment of cancers. In this study, the inhibition mechanism of 41 pyrrolopyrimidine derivatives as LIMK2 inhibitors was explored through a series of theoretical approaches. First, a model of LIMK2 was generated through molecular homology modeling, and the studied inhibitors were docked into the binding active site of LIMK2 by the docking protocol, taking into consideration the flexibility of the protein. The binding poses predicted by molecular docking for 17 selected inhibitors with different bioactivities complexed with LIMK2 underwent molecular dynamics (MD) simulations, and the binding free energies for the complexes were predicted by using the molecular mechanics/generalized born surface area (MM/GBSA) method. The predicted binding free energies correlated well with the experimental bioactivities (r(2) = 0.63 or 0.62). Next, the free energy decomposition analysis was utilized to highlight the following key structural features related to biological activity: (1) the important H-bond between Ile408 and pyrrolopyrimidine, (2) the H-bonds between the inhibitors and Asp469 and Gly471 which maintain the stability of the DFG-out conformation, and (3) the hydrophobic interactions between the inhibitors and several key residues (Leu337, Phe342, Ala345, Val358, Lys360, Leu389, Ile408, Leu458 and Leu472). Finally, a variety of LIMK2 inhibitors with a pyrrolopyrimidine scaffold were designed, some of which showed improved potency according to the predictions. Our studies suggest that the use of molecular docking with MD simulations and free energy calculations could be a powerful tool for understanding the binding mechanism of LIMK2 inhibitors and for the design of more potent LIMK2 inhibitors.

Aromatic inhibitors derived from ammonia-pretreated lignocellulose hinder bacterial ethanologenesis by activating regulatory circuits controlling inhibitor efflux and detoxification

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David H. Keating

2014-08-01

Full Text Available Efficient microbial conversion of lignocellulosic hydrolysates to biofuels is a key barrier to the economically viable deployment of lignocellulosic biofuels. A chief contributor to this barrier is the impact on microbial processes and energy metabolism of lignocellulose-derived inhibitors, including phenolic carboxylates, phenolic amides (for ammonia-pretreated biomass, phenolic aldehydes, and furfurals. To understand the bacterial pathways induced by inhibitors present in ammonia-pretreated biomass hydrolysates, which are less well studied than acid-pretreated biomass hydrolysates, we developed and exploited synthetic mimics of ammonia-pretreated corn stover hydrolysate (ACSH. To determine regulatory responses to the inhibitors normally present in ACSH, we measured transcript and protein levels in an Escherichia coli ethanologen using RNA-seq and quantitative proteomics during fermentation to ethanol of synthetic hydrolysates containing or lacking the inhibitors. Our study identified four major regulators mediating these responses, the MarA/SoxS/Rob network, AaeR, FrmR, and YqhC. Induction of these regulons was correlated with a reduced rate of ethanol production, buildup of pyruvate, depletion of ATP and NAD(PH, and an inhibition of xylose conversion. The aromatic aldehyde inhibitor 5-hydroxymethylfurfural appeared to be reduced to its alcohol form by the ethanologen during fermentation, whereas phenolic acid and amide inhibitors were not metabolized. Together, our findings establish that the major regulatory responses to lignocellulose-derived inhibitors are mediated by transcriptional rather than translational regulators, suggest that energy consumed for inhibitor efflux and detoxification may limit biofuel production, and identify a network of regulators for future synthetic biology efforts.

[Screening based on response surface methodology of multi-fractions traditional Chinese medicine with anti-influenza virus neuraminidase activity: take shuanghuanglian injection as an example].

Science.gov (United States)

Qiu, Ling-Ling; Chen, Long-Hu; Yan, Dan; Zhang, Ping; Tan, Man-Rong; Li, Zheng-Ming; Xiao, Xiao-He

2012-04-01

This study aimed to establish a novel method to screen out the combined components of multi-fractions traditional Chinese medicine (TCM), so that the internal relationship between multi-ingredients could be objectively assessed and the proportioning ratio could be optimized. Taking antiviral effect on neuraminidase activity of influenza virus as the evaluating indicator and using Box-Behnken response surface methodology, the main effective ingredients of Shuanghuanglian injection (SHL) were screened. Meanwhile, the relationship between active ingredients was discussed. Taking SHL as a comparison, the optimum proportioning ratio was predicted. The results indicated that chlorogenic acid, cryptochlorogenic acid, caffeic acid and baicalin have comparatively strong antiviral activity against influenza virus. Moreover, antagonistic action existed between chlorogenic acid and cryptochlorogenic acid, whereas synergistic action between caffeic acid and other components. The optimum proportioning ratio resulted from fitted model is: chlorogenic acid, cryptochlorogenic acid, caffeic acid and baicalin (107 microg x mL(-1) : 279 microg x mL(-1) : 7.99 microg x mL(-1) : 92 microg x mL(-1)). The antiviral activity of the recombined components is stronger than that of SHL, which was consistent with the experiment results (P < 0.05). Box-Behnken response surface methodology has the advantages of general-screening, high-performance and accurate-prediction etc, which is appropriate for screening the combined components of multi-fractions TCM and the optimization of the proportioning ratio. The proposed method can serve as a technological support for the development of modern multi-fractions TCM.

Predicting DPP-IV inhibitors with machine learning approaches

Science.gov (United States)

Cai, Jie; Li, Chanjuan; Liu, Zhihong; Du, Jiewen; Ye, Jiming; Gu, Qiong; Xu, Jun

2017-04-01

Dipeptidyl peptidase IV (DPP-IV) is a promising Type 2 diabetes mellitus (T2DM) drug target. DPP-IV inhibitors prolong the action of glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP), improve glucose homeostasis without weight gain, edema, and hypoglycemia. However, the marketed DPP-IV inhibitors have adverse effects such as nasopharyngitis, headache, nausea, hypersensitivity, skin reactions and pancreatitis. Therefore, it is still expected for novel DPP-IV inhibitors with minimal adverse effects. The scaffolds of existing DPP-IV inhibitors are structurally diversified. This makes it difficult to build virtual screening models based upon the known DPP-IV inhibitor libraries using conventional QSAR approaches. In this paper, we report a new strategy to predict DPP-IV inhibitors with machine learning approaches involving naïve Bayesian (NB) and recursive partitioning (RP) methods. We built 247 machine learning models based on 1307 known DPP-IV inhibitors with optimized molecular properties and topological fingerprints as descriptors. The overall predictive accuracies of the optimized models were greater than 80%. An external test set, composed of 65 recently reported compounds, was employed to validate the optimized models. The results demonstrated that both NB and RP models have a good predictive ability based on different combinations of descriptors. Twenty "good" and twenty "bad" structural fragments for DPP-IV inhibitors can also be derived from these models for inspiring the new DPP-IV inhibitor scaffold design.

Aromatase inhibitors and breast cancer prevention.

Science.gov (United States)

Litton, Jennifer Keating; Arun, Banu K; Brown, Powel H; Hortobagyi, Gabriel N

2012-02-01

Endocrine therapy with selective estrogen receptor modulators (SERMs) has been the mainstay of breast cancer prevention trials to date. The aromatase inhibitors, which inhibit the final chemical conversion of androgens to estrogens, have shown increased disease-free survival benefit over tamoxifen in patients with primary hormone receptor-positive breast cancer, as well as reducing the risk of developing contralateral breast cancers. The aromatase inhibitors are being actively evaluated as prevention agents for women with a history of ductal carcinoma in situ as well as for women who are considered to be at high risk for developing primary invasive breast cancer. This review evaluates the available prevention data, as evidenced by the decrease in contralateral breast cancers, when aromatase inhibitors are used in the adjuvant setting, as well as the emerging data of the aromatase inhibitors specifically tested in the prevention setting for women at high risk. Exemestane is a viable option for breast cancer prevention. We continue to await further follow-up on exemestane as well as other aromatase inhibitors in the prevention setting for women at high risk of developing breast cancer or with a history of ductal carcinoma in situ.

Monoamine Oxidase B Inhibitors in Parkinson's Disease.

Science.gov (United States)

Dezsi, Livia; Vecsei, Laszlo

2017-01-01

Parkinson's disease (PD) is a neurodegenerative disorder with a prevalence increasing with age. Oxidative stress and glutamate toxicity are involved in its pathomechanism. There are still many unmet needs of PD patients, including the alleviation of motor fluctuations and dyskinesias, and the development of therapies with neuroprotective potential. To give an overview of the pharmacological properties, the efficacy and safety of the monoamine oxidase B (MAO-B) inhibitors in the treatment of PD, with special focus on the results of randomized clinical trials. A literature search was conducted in PubMed for 'PD treatment', 'MAO-B inhibitors', 'selegiline', 'rasagiline', 'safinamide' and 'clinical trials' with 'MAO-B inhibitors' in 'Parkinson' disease'. MAO-B inhibitors have a favorable pharmacokinetic profile, improve the dopamine deficient state and may have neuroprotective properties. Safinamide exhibits an anti-glutamatergic effect as well. When applied as monotherapy, MAO-B inhibitors provide a modest, but significant improvement of motor function and delay the need for levodopa. Rasagiline and safinamide were proven safe and effective when added to a dopamine agonist in early PD. As add-on to levodopa, MAO-B inhibitors significantly reduced off-time and were comparable in efficacy to COMT inhibitors. Improvements were achieved as regards certain non-motor symptoms as well. Due to the efficacy shown in clinical trials and their favorable side-effect profile, MAO-B inhibitors are valuable drugs in the treatment of PD. They are recommended as monotherapy in the early stages of the disease and as add-on therapy to levodopa in advanced PD. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Enzyme structure and interaction with inhibitors

International Nuclear Information System (INIS)

London, R.E.

1983-01-01

This article reviews some of the results of studies on the 13 C-labeled enzyme dihydrofolate reductase (DHFR). Nuclear magnetic resonance (NMR) techniques are used in combination with isotopic labeling to learn about the structure and dynamics of this enzyme. 13 C-labeling is used for the purpose of studying enzyme/substrate and enzyme/inhibitor interactions. A second set of studies with DHFR was designed to investigate the basis for the high affinity between the inhibitor methotrexate and DHFR. The label was placed on the inhibitor, rather than the enzyme

ELISA analysis of soybean trypsin inhibitors in processed foods.

Science.gov (United States)

Brandon, D L; Bates, A H; Friedman, M

1991-01-01

Soybean proteins are widely used in human foods in a variety of forms, including infant formulas, flour, protein concentrates, protein isolates, soy sauces, textured soy fibers, and tofu. The presence of inhibitors of digestive enzymes in soy proteins impairs the nutritional quality and possibly the safety of soybeans and other legumes. Processing, based on the use of heat or fractionation of protein isolates, does not completely inactivate or remove these inhibitors, so that residual amounts of inhibitors are consumed by animals and humans. New monoclonal antibody-based immunoassays can measure low levels of the soybean Kunitz trypsin inhibitor (KTI) and the Bowman-Birk trypsin and chymotrypsin inhibitor (BBI) and the Bowman-Birk foods. The enzyme-linked immunosorbent assay (ELISA) was used to measure the inhibitor content of soy concentrates, isolates, and flours, both heated and unheated; a commercial soy infant formula; KTI and BBI with rearranged disulfide bonds; browning products derived from heat-treatment of KTI with glucose and starch; and KTI exposed to high pH. The results indicate that even low inhibitor isolates contain significant amounts of specific inhibitors. Thus, infants on soy formula consume about 10 mg of KTI plus BBI per day. The immunoassays complement the established enzymatic assays of trypsin and chymotrypsin inhibitors, and have advantages in (a) measuring low levels of inhibitors in processed foods; and (b) differentiating between the Kunitz and Bowman-Birk inhibitors. The significance of our findings for food safety are discussed.

Classification of Cytochrome P450 1A2 Inhibitors and Non-Inhibitors by Machine Learning Techniques

DEFF Research Database (Denmark)

Vasanthanathan, Poongavanam; Taboureau, Olivier; Oostenbrink, Chris

2009-01-01

of CYP1A2 inhibitors and non-inhibitors. Training and test sets consisted of about 400 and 7000 compounds, respectively. Various machine learning techniques, like binary QSAR, support vector machine (SVM), random forest, kappa nearest neighbors (kNN), and decision tree methods were used to develop...

Retro-binding thrombin active site inhibitors: identification of an orally active inhibitor of thrombin catalytic activity.

Science.gov (United States)

Iwanowicz, Edwin J; Kimball, S David; Lin, James; Lau, Wan; Han, W-C; Wang, Tammy C; Roberts, Daniel G M; Schumacher, W A; Ogletree, Martin L; Seiler, Steven M

2002-11-04

A series of retro-binding inhibitors of human alpha-thrombin was prepared to elucidate structure-activity relationships (SAR) and optimize in vivo performance. Compounds 9 and 11, orally active inhibitors of thrombin catalytic activity, were identified to be efficacious in a thrombin-induced lethality model in mice.

Contemporary protease inhibitors and cardiovascular risk

DEFF Research Database (Denmark)

Lundgren, Jens; Mocroft, Amanda; Ryom, Lene

2018-01-01

PURPOSE OF REVIEW: To review the evidence linking use of HIV protease inhibitors with excess risk of cardiovascular disease (CVD) in HIV+ populations. RECENT FINDINGS: For the two contemporary most frequently used protease inhibitors, darunavir and atazanavir [both pharmacologically boosted...

Nonnucleoside Reverse-transcriptase Inhibitor- vs Ritonavir-boosted Protease Inhibitor-based Regimens for Initial Treatment of HIV Infection

DEFF Research Database (Denmark)

Borges, Álvaro H; Lundh, Andreas; Tendal, Britta

2016-01-01

BACKGROUND: Previous studies suggest that nonnucleoside reverse-transcriptase inhibitors (NNRTIs) cause faster virologic suppression, while ritonavir-boosted protease inhibitors (PI/r) recover more CD4 cells. However, individual trials have not been powered to compare clinical outcomes. METHODS: ...

Chelation: A Fundamental Mechanism of Action of AGE Inhibitors, AGE Breakers, and Other Inhibitors of Diabetes Complications

Energy Technology Data Exchange (ETDEWEB)

Nagai, Rhoji; Murray, David B.; Metz, Thomas O.; Baynes, John

2012-03-01

Advanced glycation or glycoxidation end-products (AGE) increase in tissue proteins with age, and their rate of accumulation is increased in diabetes, nephropathy and inflammatory diseases. AGE inhibitors include a range of compounds that are proposed to act by trapping carbonyl and dicarbonyl intermediates in AGE formation. However, some among the newer generation of AGE inhibitors lack reactive functional groups that would trap reaction intermediates, indicating an alternative mechanism of action. We propose that AGE inhibitors function primarily as chelators, inhibiting metal-catalyzed oxidation reactions. The AGE-inhibitory activity of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers is also consistent with their chelating activity. Finally, compounds described as AGE breakers, or their hydrolysis products, also have strong chelating activity, suggesting that these compounds also act through their chelating activity. We conclude that chelation is the common, and perhaps the primary, mechanism of action of AGE inhibitors and breakers, and that chronic, mild chelation therapy should prove useful in treatment of diabetes and age-related diseases characterized by oxidative stress, inflammation and increased chemical modification of tissue proteins by advanced glycoxidation and lipoxidation end-products.

Potential non-oncological applications of histone deacetylase inhibitors.

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Ververis, Katherine; Karagiannis, Tom C

2011-01-01

Histone deacetylase inhibitors have emerged as a new class of anticancer therapeutic drugs. Their clinical utility in oncology stems from their intrinsic cytotoxic properties and combinatorial effects with other conventional cancer therapies. To date, the histone deacetylase inhibitors suberoylanilide hydroxamic acid (Vorinostat, Zolinza®) and depsipeptide (Romidepsin, Istodax®) have been approved by the US Food and Drug Administration for the treatment of refractory cutaneous T-cell lymphoma. Further, there are currently over 100 clinical trials involving the use of histone deacetylase inhibitors in a wide range of solid and hematological malignancies. The therapeutic potential of histone deacetylase inhibitors has also been investigated for numerous other diseases. For example, the cytotoxic properties of histone deacetylase inhibitors are currently being harnessed as a potential treatment for malaria, whereas the efficacy of these compounds for HIV relies on de-silencing latent virus. The anti-inflammatory properties of histone deacetylase inhibitors are the predominant mechanisms for other diseases, such as hepatitis, systemic lupus erythematosus and a wide range of neurodegenerative conditions. Additionally, histone deacetylase inhibitors have been shown to be efficacious in animal models of cardiac hypertrophy and asthma. Broad-spectrum histone deacetylase inhibitors are clinically available and have been used almost exclusively in preclinical systems to date. However, it is emerging that class- or isoform-specific compounds, which are becoming more readily available, may be more efficacious particularly for non-oncological applications. The aim of this review is to provide an overview of the effects and clinical potential of histone deacetylase inhibitors in various diseases. Apart from applications in oncology, the discussion is focused on the potential efficacy of histone deacetylase inhibitors for the treatment of neurodegenerative diseases, cardiac

Characterization of inhibitor(s) of β-glucuronidase enzyme activity in GUS-transgenic wheat

KAUST Repository

Ramadan, Ahmed M Ali

2011-06-26

The uidA gene, encoding for β-glucuronidase (GUS), is the most frequently used reporter gene in plants. As a reporter enzyme, GUS can be assayed both qualitatively and quantitatively. In wheat, there are numerous reports of failure in detecting GUS enzyme activity in tissues of transgenic plants, while other reports have suggested presence of β-glucuronidase inhibitor(s) in wheat tissues. In the present study, we show that the β-glucuronidase enzyme activity is not only tissue-specific but also genotype-dependent. Our data demonstrate that the glucuronic acid could be the candidate inhibitor for β-glucuronidase enzyme activity in wheat leaves and roots. It should be noted that the assays to detect β-glucuronidase enzyme activity in wheat should be interpreted carefully. Based on the data of our present study, we recommend studying the chemical pathways, the unintended effects and the possible loss-of-function of any candidate transgene prior to transformation experiments. © 2011 Springer Science+Business Media B.V.

Characterization of inhibitor(s) of β-glucuronidase enzyme activity in GUS-transgenic wheat

KAUST Repository

Ramadan, Ahmed M Ali; Eissa, Hala F.; El-Domyati, Fotouh M.; Saleh, Osama Mesilhy; Ibrahim, Nasser E.; Salama, M. I.; Mahfouz, Magdy M.; Bahieldin, Ahmed M.

2011-01-01

The uidA gene, encoding for β-glucuronidase (GUS), is the most frequently used reporter gene in plants. As a reporter enzyme, GUS can be assayed both qualitatively and quantitatively. In wheat, there are numerous reports of failure in detecting GUS enzyme activity in tissues of transgenic plants, while other reports have suggested presence of β-glucuronidase inhibitor(s) in wheat tissues. In the present study, we show that the β-glucuronidase enzyme activity is not only tissue-specific but also genotype-dependent. Our data demonstrate that the glucuronic acid could be the candidate inhibitor for β-glucuronidase enzyme activity in wheat leaves and roots. It should be noted that the assays to detect β-glucuronidase enzyme activity in wheat should be interpreted carefully. Based on the data of our present study, we recommend studying the chemical pathways, the unintended effects and the possible loss-of-function of any candidate transgene prior to transformation experiments. © 2011 Springer Science+Business Media B.V.

The "SWOT" of BRAF inhibition in melanoma: RAF inhibitors, MEK inhibitors or both?

Science.gov (United States)

Nissan, Moriah H; Solit, David B

2011-12-01

Activating mutations in the BRAF gene are among the most prevalent kinase mutations in human cancer. BRAF mutations are most frequent in patients with melanoma where they occur in approximately 50% of patients with advanced disease. Remarkable clinical activity has recently been reported with highly selective RAF inhibitors in melanoma patients whose tumors harbor V600E BRAF mutations. The response rates of RAF inhibitors in patients with BRAF-mutant melanomas far exceed the activity level of any prior therapy studied in this disease. The results suggest that we have entered an era of personalized therapy for patients with metastatic melanoma in which treatment selection will be guided by BRAF mutational status. This review will discuss the strengths, weaknesses, opportunities and threats ("SWOT") of developing RAF and MEK selective inhibitors as anti-cancer therapies, recent insights into the mechanisms of intrinsic and acquired resistance to these agents, and current efforts to develop mechanism-based combination therapies.

Regulation of collagenase inhibitor production in chondrosarcoma chondrocytes

International Nuclear Information System (INIS)

Harper, J.; Harper, E.

1987-01-01

Swarm rat chondrosarcoma chondrocytes produce an inhibitor of collagenase. This inhibitor is similar to those isolated from normal cartilage tissues. These cells will synthesize proteins in the absence of serum. Since serum contains inhibitors of collagenase, it is necessary to culture cells without serum in order to obtain accurate measurements of enzyme and inhibitor levels. They examined the effect of insulin on inhibitor secretion by cultures of Swarm rat chondrosarcoma chondrocytes. They observed a 2.5 to 3.5 fold stimulation of inhibitory activity in the presence of as little as 10 ng/ml insulin as compared to controls in serum free Dulbecco's modified Eagle's medium supplemented with 4.5 g/l glucose. The units of inhibitor were determined over a 7 day culture period. Medium was harvested daily and assayed for collagenase activity and for inhibition of a known collagenase from rabbit skin or human skin, using the 14 C-glycine peptide release assay. The amount of inhibitor obtained from days 2 through 7 were: 1.4 unit (control), 3.8 units (10 ng/ml insulin), 5.2 units (1 μg/ml insulin). The addition of 1 mM dibutyryl cyclic AMP to these chondrocytes in the presence of 1 μg/ml insulin caused a decrease in the level of inhibitor, suggesting that a dephosphorylation event may be necessary for this stimulation by insulin to occur

An Updated Review of Tyrosinase Inhibitors

Directory of Open Access Journals (Sweden)

Te-Sheng Chang

2009-05-01

Full Text Available Tyrosinase is a multifunctional, glycosylated, and copper-containing oxidase, which catalyzes the first two steps in mammalian melanogenesis and is responsible for enzymatic browning reactions in damaged fruits during post-harvest handling and processing. Neither hyperpigmentation in human skin nor enzymatic browning in fruits are desirable. These phenomena have encouraged researchers to seek new potent tyrosinase inhibitors for use in foods and cosmetics. This article surveys tyrosinase inhibitors newly discovered from natural and synthetic sources. The inhibitory strength is compared with that of a standard inhibitor, kojic acid, and their inhibitory mechanisms are discussed.

Cellular growth kinetics distinguish a cyclophilin inhibitor from an HSP90 inhibitor as a selective inhibitor of hepatitis C virus.

Directory of Open Access Journals (Sweden)

Rudolf K F Beran

Full Text Available During antiviral drug discovery, it is critical to distinguish molecules that selectively interrupt viral replication from those that reduce virus replication by adversely affecting host cell viability. In this report we investigate the selectivity of inhibitors of the host chaperone proteins cyclophilin A (CypA and heat-shock protein 90 (HSP90 which have each been reported to inhibit replication of hepatitis C virus (HCV. By comparing the toxicity of the HSP90 inhibitor, 17-(Allylamino-17-demethoxygeldanamycin (17-AAG to two known cytostatic compounds, colchicine and gemcitabine, we provide evidence that 17-AAG exerts its antiviral effects indirectly through slowing cell growth. In contrast, a cyclophilin inhibitor, cyclosporin A (CsA, exhibited selective antiviral activity without slowing cell proliferation. Furthermore, we observed that 17-AAG had little antiviral effect in a non-dividing cell-culture model of HCV replication, while CsA reduced HCV titer by more than two orders of magnitude in the same model. The assays we describe here are useful for discriminating selective antivirals from compounds that indirectly affect virus replication by reducing host cell viability or slowing cell growth.

Structures of human Golgi-resident glutaminyl cyclase and its complexes with inhibitors reveal a large loop movement upon inhibitor binding.

Science.gov (United States)

Huang, Kai-Fa; Liaw, Su-Sen; Huang, Wei-Lin; Chia, Cho-Yun; Lo, Yan-Chung; Chen, Yi-Ling; Wang, Andrew H-J

2011-04-08

Aberrant pyroglutamate formation at the N terminus of certain peptides and proteins, catalyzed by glutaminyl cyclases (QCs), is linked to some pathological conditions, such as Alzheimer disease. Recently, a glutaminyl cyclase (QC) inhibitor, PBD150, was shown to be able to reduce the deposition of pyroglutamate-modified amyloid-β peptides in brain of transgenic mouse models of Alzheimer disease, leading to a significant improvement of learning and memory in those transgenic animals. Here, we report the 1.05-1.40 Å resolution structures, solved by the sulfur single-wavelength anomalous dispersion phasing method, of the Golgi-luminal catalytic domain of the recently identified Golgi-resident QC (gQC) and its complex with PBD150. We also describe the high-resolution structures of secretory QC (sQC)-PBD150 complex and two other gQC-inhibitor complexes. gQC structure has a scaffold similar to that of sQC but with a relatively wider and negatively charged active site, suggesting a distinct substrate specificity from sQC. Upon binding to PBD150, a large loop movement in gQC allows the inhibitor to be tightly held in its active site primarily by hydrophobic interactions. Further comparisons of the inhibitor-bound structures revealed distinct interactions of the inhibitors with gQC and sQC, which are consistent with the results from our inhibitor assays reported here. Because gQC and sQC may play different biological roles in vivo, the different inhibitor binding modes allow the design of specific inhibitors toward gQC and sQC.

Stabilization versus inhibition of TAFIa by competitive inhibitors in vitro

NARCIS (Netherlands)

Walker, J.B.; Hughes, B.; James, I.; Haddock, P.; Kluft, C.; Bajzar, L.

2003-01-01

Two competitive inhibitors of TAFIa (activated thrombin-activable fibrinolysis inhibitor), 2-guanidinoethyl-mercaptosuccinic acid and potato tuber carboxypeptidase inhibitor, variably affect fibrinolysis of clotted human plasma. Depending on their concentration, the inhibitors shortened, prolonged,

Replacement inhibitors for tank farm cooling coil systems

International Nuclear Information System (INIS)

Hsu, T.C.

1995-01-01

Sodium chromate has been an effective corrosion inhibitor for the cooling coil systems in Savannah River Site (SRS) waste tanks for over 40 years. Due to their age and operating history, cooling coils occasionally fail allowing chromate water to leak into the environment. When the leaks spill 10 lbs. or more of sodium chromate over a 24-hr period, the leak incidents are classified as Unusual Occurrences (UO) per CERCLA (Comprehensive Environmental Response, Compensation and Liability Act). The cost of reporting and cleaning up chromate spills prompted High Level Waste Engineering (HLWE) to initiate a study to investigate alternative tank cooling water inhibitor systems and the associated cost of replacement. Several inhibitor systems were investigated as potential alternatives to sodium chromate. All would have a lesser regulatory impact, if a spill occurred. However, the conversion cost is estimated to be $8.5 million over a period of 8 to 12 months to convert all 5 cooling systems. Although each of the alternative inhibitors examined is effective in preventing corrosion, there is no inhibitor identified that is as effective as chromate. Assuming 3 major leaks a year (the average over the past several years), the cost of maintaining the existing inhibitor was estimated at $0.5 million per year. Since there is no economic or regulatory incentive to replace the sodium chromate with an alternate inhibitor, HLWE recommends that sodium chromate continue to be used as the inhibitor for the waste tank cooling systems

The safety of proton pump inhibitors in pregnancy

DEFF Research Database (Denmark)

Nielsen, Gunnar Lauge; Sørensen, Henrik Toft; Thulstrup, Ane Marie

1999-01-01

AIM: To assess the safety of proton pump inhibitors during pregnancy. METHODS: Fifty-one pregnant women exposed to proton pump inhibitors around the time of conception or during pregnancy were compared with 13 327 controls without exposure to any prescribed drug in a population-based study based...... birth weight or number of preterm deliveries in pregnancies exposed to proton pump inhibitors. However, further monitoring is warranted in order to establish or rule out a potential association between the use of proton pump inhibitors and increased risk of either cardiac malformations or preterm birth....

Epithelial tissue hyperplasia induced by the RAF inhibitor PF-04880594 is attenuated by a clinically well-tolerated dose of the MEK inhibitor PD-0325901.

Science.gov (United States)

Torti, Vince R; Wojciechowicz, Donald; Hu, Wenyue; John-Baptiste, Annette; Evering, Winston; Troche, Gabriel; Marroquin, Lisa D; Smeal, Tod; Yamazaki, Shinji; Palmer, Cynthia L; Burns-Naas, Leigh Ann; Bagrodia, Shubha

2012-10-01

Clinical trials of selective RAF inhibitors in patients with melanoma tumors harboring activated BRAFV600E have produced very promising results, and a RAF inhibitor has been approved for treatment of advanced melanoma. However, about a third of patients developed resectable skin tumors during the course of trials. This is likely related to observations that RAF inhibitors activate extracellular signal-regulated kinase (ERK) signaling, stimulate proliferation, and induce epithelial hyperplasia in preclinical models. Because these findings raise safety concerns about RAF inhibitor development, we further investigated the underlying mechanisms. We showed that the RAF inhibitor PF-04880594 induces ERK phosphorylation and RAF dimerization in those epithelial tissues that undergo hyperplasia. Hyperplasia and ERK hyperphosphorylation are prevented by treatment with the mitogen-activated protein/extracellular signal-regulated kinase (MEK) inhibitor PD-0325901 at exposures that extrapolate to clinically well-tolerated doses. To facilitate mechanistic and toxicologic studies, we developed a three-dimensional cell culture model of epithelial layering that recapitulated the RAF inhibitor-induced hyperplasia and reversal by MEK inhibitor in vitro. We also showed that PF-04880594 stimulates production of the inflammatory cytokine interleukin 8 in HL-60 cells, suggesting a possible mechanism for the skin flushing observed in dogs. The complete inhibition of hyperplasia by MEK inhibitor in epithelial tissues does not seem to reduce RAF inhibitor efficacy and, in fact, allows doubling of the PF-04880594 dose without toxicity usually associated with such doses. These findings indicated that combination treatment with MEK inhibitors might greatly increase the safety and therapeutic index of RAF inhibitors for the treatment of melanoma and other cancers. ©2012 AACR.

Janus Associated Kinases Inhibitors in the Pharmacological Thera

Directory of Open Access Journals (Sweden)

Daniela Santos1

2017-01-01

Full Text Available Janus associated kinases inhibitors are a new strategy for the treatment of different clinical conditions like immunologic, inflammatory and oncology disorders. The aim of this study was to perform a review of all Janus associated kinases inhibitors available in national and international pharmaceutical market, their therapeutic indications and adverse effects, and the potential indications for investigation of those already available in the pharmaceutical market. It was also performed a review of the main new Janus associated kinases inhibitors that are still in clinical research. A literature review was conducted by consulting the summary of product characteristics of Janus associated kinases inhibitors available in the pharmaceutical market and a research in the bibliographic database PubMed using the terms «JAK inhibitors», «Janus associated kinases inhibitors» and «Janus kinases inhibitors». Ninety-five publications were included in the present review, published from January 2014 to January 2015. Drug databases of the European Medicines Agency and United States Food and Drug Administration were also consulted to search for Janus associated kinases inhibitors authorized in clinical practice. Currently, ruxolitinib and tofacitinib are available in the pharmaceutical market and oclatinib is approved as a veterinary medicinal product. Both drugs approved for human use have major adverse effects at hematological and immunological levels, which enhance the importance of the pharmacist’s role in the monitoring of patients involved in these treatments. However, several molecules are in pre-clinical and clinical studies trying to prove its potential in the treatment of several immunologic, inflammatory and oncology disorders. Thus, it is still necessary to deepen the knowledge in this area in order to overcome the risks of therapy with these agents. These risks weighed against the benefits of its clinical use have compromised the progress of

Positron emitter labeled enzyme inhibitors

International Nuclear Information System (INIS)

Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.; Langstrom, B.

1990-01-01

This invention involves a new strategy for imagining and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography

Inhibition of matrix metalloproteinase-2 by PARP inhibitors

International Nuclear Information System (INIS)

Nicolescu, Adrian C.; Holt, Andrew; Kandasamy, Arulmozhi D.; Pacher, Pal; Schulz, Richard

2009-01-01

Matrix metalloproteinase-2 (MMP-2), a ubiquitously expressed zinc-dependent endopeptidase, and poly(ADP-ribosyl) polymerase (PARP), a nuclear enzyme regulating DNA repair, are activated by nitroxidative stress associated with various pathologies. As MMP-2 plays a detrimental role in heart injuries resulting from enhanced nitroxidative stress, where PARP and MMP inhibitors are beneficial, we hypothesized that PARP inhibitors may affect MMP-2 activity. Using substrate degradation assays to determine MMP-2 activity we found that four PARP inhibitors (3-AB, PJ-34, 5-AIQ, and EB-47) inhibited 64 kDa MMP-2 in a concentration-dependent manner. The IC 50 values of PJ-34 and 5-AIQ were in the high micromolar range and comparable to those of known MMP-2 inhibitors doxycycline, minocycline or o-phenanthroline, whereas those for 3-AB and EB-47 were in the millimolar range. Co-incubation of PARP inhibitors with doxycycline showed an additive inhibition of MMP-2 that was significant for 3-AB alone. These data demonstrate that the protective effects of some PARP inhibitors may include inhibition of MMP-2 activity.

Inhibition of matrix metalloproteinase-2 by PARP inhibitors

Energy Technology Data Exchange (ETDEWEB)

Nicolescu, Adrian C.; Holt, Andrew; Kandasamy, Arulmozhi D. [Departments of Pharmacology and Pediatrics, Cardiovascular Research Centre, University of Alberta, Edmonton, Alta., Canada T6G 2S2 (Canada); Pacher, Pal [National Institutes of Health, NIAAA, Laboratory of Physiologic Studies, Bethesda, MD (United States); Schulz, Richard, E-mail: richard.schulz@ualberta.ca [Departments of Pharmacology and Pediatrics, Cardiovascular Research Centre, University of Alberta, Edmonton, Alta., Canada T6G 2S2 (Canada)

2009-10-02

Matrix metalloproteinase-2 (MMP-2), a ubiquitously expressed zinc-dependent endopeptidase, and poly(ADP-ribosyl) polymerase (PARP), a nuclear enzyme regulating DNA repair, are activated by nitroxidative stress associated with various pathologies. As MMP-2 plays a detrimental role in heart injuries resulting from enhanced nitroxidative stress, where PARP and MMP inhibitors are beneficial, we hypothesized that PARP inhibitors may affect MMP-2 activity. Using substrate degradation assays to determine MMP-2 activity we found that four PARP inhibitors (3-AB, PJ-34, 5-AIQ, and EB-47) inhibited 64 kDa MMP-2 in a concentration-dependent manner. The IC{sub 50} values of PJ-34 and 5-AIQ were in the high micromolar range and comparable to those of known MMP-2 inhibitors doxycycline, minocycline or o-phenanthroline, whereas those for 3-AB and EB-47 were in the millimolar range. Co-incubation of PARP inhibitors with doxycycline showed an additive inhibition of MMP-2 that was significant for 3-AB alone. These data demonstrate that the protective effects of some PARP inhibitors may include inhibition of MMP-2 activity.

The Wonders of Phosphodiesterase‑5 Inhibitors: A Majestic History

African Journals Online (AJOL)

A milestone in drug discovery was the selective inhibitors of. PDE‑5 that ... the pharmacotherapeutics of PDE‑5 inhibitors and the majestic history that led to their discovery. ..... including HIV protease inhibitors, ketoconazole, itraconazole,.

Inactivation of proteinaceous protease inhibitors of soybeans by isolated fungi

NARCIS (Netherlands)

Meijer, M.M.T.; Spekking, W.T.J.; Sijtsma, L.; Bont, de J.A.M.

1995-01-01

Proteinaceous protease inhibitors, Kunitz Soybean Trypsin Inhibitor (KSTI) and Bowman Birk Inhibitor (BBI), in legume seeds reduce the digestibility of proteins in feed of monogastric animals. Enzymatic inactivation of these inhibitors will increase the nutritional value of the feed. The aim of this

SGLT2 inhibitors: are they safe?

Science.gov (United States)

Filippas-Ntekouan, Sebastian; Filippatos, Theodosios D; Elisaf, Moses S

2018-01-01

Sodium-glucose linked transporter type 2 (SGLT2) inhibitors are a relatively new class of antidiabetic drugs with positive cardiovascular and kidney effects. The aim of this review is to present the safety issues associated with SGLT2 inhibitors. Urogenital infections are the most frequently encountered adverse events, although tend to be mild to moderate and are easily manageable with standard treatment. Although no increased acute kidney injury risk was evident in the major trials, the mechanism of action of these drugs requires caution when they are administered in patients with extracellular volume depletion or with drugs affecting renal hemodynamics. Canagliflozin raised the risk of amputations and the rate of fractures in the CANVAS trial, although more data are necessary before drawing definite conclusions. The risk of euglycemic diabetic ketoacidosis seems to be minimal when the drugs are prescribed properly. Regarding other adverse events, SGLT2 inhibitors do not increase the risk of hypoglycemia even when co-administered with insulin, but a decrease in the dose of sulphonylureas may be needed. The available data do not point to a causative role of SGLT2 inhibitors on malignancy risk, however, these drugs should be used with caution in patients with known hematuria or history of bladder cancer. SGLT2 inhibitors seem to be safe and effective in the treatment of diabetes but more studies are required to assess their long-term safety.

Janus kinase inhibitors: jackpot or potluck?

Directory of Open Access Journals (Sweden)

Pavithran Keechilat

2012-06-01

Full Text Available The reports of a unique mutation in the Janus kinase-2 gene (JAK2 in polycythemia vera by several independent groups in 2005 quickly spurred the development of the Janus kinase inhibitors. In one of the great victories of translational research in recent times, the first smallmolecule Janus kinase inhibitor ruxolitinib entered a phase I trial in 2007. With the approval of ruxolitinib by the US Federal Drug Administration in November 2011 for high-risk and intermediate-2 risk myelofibrosis, a change in paradigm has occurred in the management of a subset of myeloproliferative neoplasms (MPN: primary myelofibrosis, post-polycythemia vera myelofibrosis, and post-essential thrombocythemia myelofibrosis. Whereas the current evidence for ruxolitinib only covers high-risk and intermediate-2 risk myelofibrosis, inhibitors with greater potency are likely to offer better disease control and survival advantage in patients belonging to these categories, and possibly to the low-risk and intermediate-1 risk categories of MPN as well. But use of the Janus kinase inhibitors also probably has certain disadvantages, such as toxicity, resistance, withdrawal phenomenon, non-reversal of histology, and an implausible goal of disease clone eradication, some of which could offset the gains. In spite of this, Janus kinase inhibitors are here to stay, and for use in more than just myeloproliferative neoplasms.

Experimental and theoretical studies of benzoxazines corrosion inhibitors

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Abdulhadi Kadhim

Full Text Available 2-Methyl-4H-benzo[d][1,3]oxazin-4-one (BZ1 and 3-amino-2-methylquinazolin-4(3H-one (BZ2 were evaluated for their corrosion inhibition properties on mild steel (MS in hydrochloric acid solution by weight loss technique and scanning electron microscopy. Results show the inhibition efficiency values depend on the amount of nitrogen in the inhibitor, the inhibitor concentration and the inhibitor molecular weight with maximum inhibition efficiency of 89% and 65% for BZ2 and BZ1 at highest concentration of the compounds. Keywords: Methylquinazoline, Benzoxazines, Corrosion, Inhibitors

Acid corrosion inhibitor

Energy Technology Data Exchange (ETDEWEB)

Chen, N G

1964-04-28

An acid corrosion inhibitor is prepared by a 2-stage vacuum evaporation of effluents obtained from the ammonia columns of the coking oven plant. The effluent, leaving a scrubber in which the phenols are removed at a temperature of 98$C, passes through a quartz filter and flows into a heated chamber in which it is used for preheating a solution circulating through a vacuum unit, maintaining the temperature of the solution at 55$ to 60$C. The effluent enters a large tank in which it is boiled at 55$ to 60$C under 635 to 640 mm Hg pressure. Double evaporation of this solution yields a very effective acid corrosion inhibitor. Its corrosion-preventing effect is 97.9% compared with 90.1% for thiourea and 88.5% for urotropin under identical conditions.

Novel dual small-molecule HIV inhibitors: scaffolds and discovery strategies.

Science.gov (United States)

Song, Anran; Yu, Haiqing; Wang, Changyuan; Zhu, Xingqi; Liu, Kexin; Ma, Xiaodong

2015-01-01

Searching for safe and effective treatments for HIV infection is still a great challenge worldwide in spite of the 27 marketed anti-HIV drugs and the powerful highly active antiretroviral therapy (HAART). As a promising prospect for generation of new HIV therapy drugs, multiple ligands (MDLs) were greatly focused on recently due to their lower toxicity, simplified dosing and patient adherence than single-target drugs. Till now, by disrupting two active sites or steps of HIV replications, a number of HIV dual inhibitors, such as CD4-gssucap120 inhibitors, CXCR4-gp20 inhibitors, RT-CXCR4 inhibitors, RT-protease inhibitors, RT-integrase inhibitors, and RTassociated functions inhibitors have been identified. Generally, these dual inhibitors were discovered mainly through screening approaches and design strategies. Of these compounds, the molecules bearing small skeletons exhibited strong anti-HIV activity and aroused great attention recently. Reviewing the progress of the dual small-molecule HIV inhibitors from the point of view of their scaffolds and discovery strategies will provide valuable information for producing more effective anti-HIV drugs. In this regard, novel dual small-molecule HIV inhibitors were illustrated, and their discovery paradigms as the major contents were also summarized in this manuscript.

Protection of pigs against pandemic swine origin H1N1 influenza A virus infection by hemagglutinin- or neuraminidase-expressing attenuated pseudorabies virus recombinants.

Science.gov (United States)

Klingbeil, Katharina; Lange, Elke; Blohm, Ulrike; Teifke, Jens P; Mettenleiter, Thomas C; Fuchs, Walter

2015-03-02

Influenza is an important respiratory disease of pigs, and may lead to novel human pathogens like the 2009 pandemic H1N1 swine-origin influenza virus (SoIV). Therefore, improved influenza vaccines for pigs are required. Recently, we demonstrated that single intranasal immunization with a hemagglutinin (HA)-expressing pseudorabies virus recombinant of vaccine strain Bartha (PrV-Ba) protected pigs from H1N1 SoIV challenge (Klingbeil et al., 2014). Now we investigated enhancement of efficacy by prime-boost vaccination and/or intramuscular administration. Furthermore, a novel PrV-Ba recombinant expressing codon-optimized N1 neuraminidase (NA) was included. In vitro replication of this virus was only slightly affected compared to parental virus. Unlike HA, the abundantly expressed NA was efficiently incorporated into PrV particles. Immunization of pigs with the two PrV recombinants, either singly or in combination, induced B cell proliferation and the expected SoIV-specific antibodies, whose titers increased substantially after boost vaccination. After immunization of animals with either PrV recombinant H1N1 SoIV challenge virus replication was significantly reduced compared to PrV-Ba vaccinated or naïve controls. Protective efficacy of HA-expressing PrV was higher than of NA-expressing PrV, and not significantly enhanced by combination. Despite higher serum antibody titers obtained after intramuscular immunization, transmission of challenge virus to naïve contact animals was only prevented after intranasal prime-boost vaccination with HA-expressing PrV-Ba. Copyright © 2015 Elsevier B.V. All rights reserved.

Nanostructured glycan architecture is important in the inhibition of influenza A virus infection

Science.gov (United States)

Kwon, Seok-Joon; Na, Dong Hee; Kwak, Jong Hwan; Douaisi, Marc; Zhang, Fuming; Park, Eun Ji; Park, Jong-Hwan; Youn, Hana; Song, Chang-Seon; Kane, Ravi S.; Dordick, Jonathan S.; Lee, Kyung Bok; Linhardt, Robert J.

2017-01-01

Rapid change and zoonotic transmission to humans have enhanced the virulence of the influenza A virus (IAV). Neutralizing antibodies fail to provide lasting protection from seasonal epidemics. Furthermore, the effectiveness of anti-influenza neuraminidase inhibitors has declined because of drug resistance. Drugs that can block viral attachment and cell entry independent of antigenic evolution or drug resistance might address these problems. We show that multivalent 6‧-sialyllactose-polyamidoamine (6SL-PAMAM) conjugates, when designed to have well-defined ligand valencies and spacings, can effectively inhibit IAV infection. Generation 4 (G4) 6SL-PAMAM conjugates with a spacing of around 3 nm between 6SL ligands (S3-G4) showed the strongest binding to a hemagglutinin trimer (dissociation constant of 1.6 × 10-7 M) and afforded the best inhibition of H1N1 infection. S3-G4 conjugates were resistant to hydrolysis by H1N1 neuraminidase. These conjugates protected 75% of mice from a lethal challenge with H1N1 and prevented weight loss in infected animals. The structure-based design of multivalent nanomaterials, involving modulation of nanoscale backbone structures and number and spacing between ligands, resulted in optimal inhibition of IAV infection. This approach may be broadly applicable for designing effective and enduring therapeutic protection against human or avian influenza viruses.

SGLT2 inhibitors: molecular design and potential differences in effect.

Science.gov (United States)

Isaji, Masayuki

2011-03-01

The physiological and pathological handling of glucose via sodium-glucose cotransporter-2 (SGLT2) in the kidneys has been evolving, and SGLT2 inhibitors have been focused upon as a novel drug for treating diabetes. SGLT2 inhibitors enhance renal glucose excretion by inhibiting renal glucose reabsorption. Consequently, SGLT2 inhibitors reduce plasma glucose insulin independently and improve insulin resistance in diabetes. To date, various SGLT2 inhibitors have been developed and evaluated in clinical studies. The potency and positioning of SGLT2 inhibitors as an antidiabetic drug are dependent on their characteristic profile, which induces selectivity, efficacy, pharmacokinetics, and safety. This profile decides which SGLT2 inhibitors can be expected for application of the theoretical concept of reducing renal glucose reabsorption for the treatment of diabetes. I review the structure and advancing profile of various SGLT2 inhibitors, comparing their similarities and differences, and discuss the expected SGLT2 inhibitors for an emerging category of antidiabetic drugs.

Mutation analysis of 2009 pandemic influenza A(H1N1 viruses collected in Japan during the peak phase of the pandemic.

Directory of Open Access Journals (Sweden)

Jean-Étienne Morlighem

Full Text Available BACKGROUND: Pandemic influenza A(H1N1 virus infection quickly circulated worldwide in 2009. In Japan, the first case was reported in May 2009, one month after its outbreak in Mexico. Thereafter, A(H1N1 infection spread widely throughout the country. It is of great importance to profile and understand the situation regarding viral mutations and their circulation in Japan to accumulate a knowledge base and to prepare clinical response platforms before a second pandemic (pdm wave emerges. METHODOLOGY: A total of 253 swab samples were collected from patients with influenza-like illness in the Osaka, Tokyo, and Chiba areas both in May 2009 and between October 2009 and January 2010. We analyzed partial sequences of the hemagglutinin (HA and neuraminidase (NA genes of the 2009 pdm influenza virus in the collected clinical samples. By phylogenetic analysis, we identified major variants of the 2009 pdm influenza virus and critical mutations associated with severe cases, including drug-resistance mutations. RESULTS AND CONCLUSIONS: Our sequence analysis has revealed that both HA-S220T and NA-N248D are major non-synonymous mutations that clearly discriminate the 2009 pdm influenza viruses identified in the very early phase (May 2009 from those found in the peak phase (October 2009 to January 2010 in Japan. By phylogenetic analysis, we found 14 micro-clades within the viruses collected during the peak phase. Among them, 12 were new micro-clades, while two were previously reported. Oseltamivir resistance-related mutations, i.e., NA-H275Y and NA-N295S, were also detected in sporadic cases in Osaka and Tokyo.

Continued dominance of pandemic A(H1N1 2009 influenza in Victoria, Australia in 2010

Directory of Open Access Journals (Sweden)

James E. Fielding

2011-08-01

Full Text Available The 2010 Victorian influenza season was characterized by normal seasonal influenza activity and the dominance of the pandemic A(H1N1 2009 strain. General Practice Sentinel Surveillance rates peaked at 9.4 ILI cases per 1000 consultations in week 36 for metropolitan practices, and at 10.5 ILI cases per 1000 in the following week for rural practices. Of the 678 ILI cases, 23% were vaccinated, a significantly higher percentage than in previous years. A significantly higher percentage of ILI patients were swabbed in 2010 compared to 2003–2008, but similar to 2009, with a similar percentage being positive for influenza as in previous years. Vaccination rates increased with patient age. Melbourne Medical Deputising Service rates peaked in week 35 at 19.1 ILI cases per 1000 consultations. Of the 1914 cases of influenza notified to the Department of Health, Victoria, 1812 (95% were influenza A infections - 1001 (55% pandemic A(H1N1 2009, 4 (<1% A(H3N2 and 807 (45% not subtyped; 88 (5% were influenza B; and 14 (< 1% were influenza A and B co-infections. The World Health Organization Collaborating Centre for Reference and Research on Influenza tested 403 isolates of which 261 were positive for influenza, 250 of which were influenza A and 11 were influenza B. Ninety-two per cent of the influenza A viruses were pandemic A(H1N1 2009, and following antigenic analysis all of these were found to be similar to the current vaccine strain. Three viruses (0.9% were found to be oseltamivir resistant due to an H275Y mutation in the neuraminidase gene.

Epidemiological and clinical characteristics of humans with avian influenza A (H7N9 infection in Guangdong, China, 2013–2017

Directory of Open Access Journals (Sweden)

Yuwei Yang

2017-12-01

Full Text Available Objective: To describe the demographics and clinical characteristics of patients with A (H7N9 infection, to test the differences in the distribution of demographics and clinical characteristics by clinical severity, and to explore potential factors associated with clinical severity. Methods: This retrospective study was conducted to collect epidemiological and clinical information regarding the confirmed cases in Guangdong through field investigation and review of medical records. Results: Of the 256 cases, 100 (39.0% patients died, and 168 (65.6% patients were admitted to ICUs. The male-to-female ratio was approximately 2.0:1, and the median age was 56 years (range, 1 to 88. Among the 215 patients accepting oseltamivir treatment, the median time from the onset of illness to oseltamivir treatment was 5 days (range, 0 to 16; 35 patients received zanamivir treatment after a median of 8 days (range, 0 to 23. The univariable logistic regression models demonstrated that time from the onset of illness to oseltamivir treatment (OR = 1.10, 95% CI = 1.01–1.10 and zanamivir treatment (OR = 1.05, 95% CI = 1.02–1.07 were associated with the death of patients. Conclusions: Preventive measures should focus on high-risk populations, such as the elderly and the groups with high frequency exposure to live poultry. Earlier oseltamivir and zanamivir treatment were recommended. Keywords: Epidemiological characteristics, Clinical characteristics, Avian influenza, H7N9 subtype

Microarray-based screening of heat shock protein inhibitors.

Science.gov (United States)

Schax, Emilia; Walter, Johanna-Gabriela; Märzhäuser, Helene; Stahl, Frank; Scheper, Thomas; Agard, David A; Eichner, Simone; Kirschning, Andreas; Zeilinger, Carsten

2014-06-20

Based on the importance of heat shock proteins (HSPs) in diseases such as cancer, Alzheimer's disease or malaria, inhibitors of these chaperons are needed. Today's state-of-the-art techniques to identify HSP inhibitors are performed in microplate format, requiring large amounts of proteins and potential inhibitors. In contrast, we have developed a miniaturized protein microarray-based assay to identify novel inhibitors, allowing analysis with 300 pmol of protein. The assay is based on competitive binding of fluorescence-labeled ATP and potential inhibitors to the ATP-binding site of HSP. Therefore, the developed microarray enables the parallel analysis of different ATP-binding proteins on a single microarray. We have demonstrated the possibility of multiplexing by immobilizing full-length human HSP90α and HtpG of Helicobacter pylori on microarrays. Fluorescence-labeled ATP was competed by novel geldanamycin/reblastatin derivatives with IC50 values in the range of 0.5 nM to 4 μM and Z(*)-factors between 0.60 and 0.96. Our results demonstrate the potential of a target-oriented multiplexed protein microarray to identify novel inhibitors for different members of the HSP90 family. Copyright © 2014 Elsevier B.V. All rights reserved.

Treatment with a JNK inhibitor increases, whereas treatment with a p38 inhibitor decreases, H2O2-induced calf pulmonary arterial endothelial cell death.

Science.gov (United States)

Park, Woo Hyun

2017-08-01

Oxidative stress induces apoptosis in endothelial cells (ECs). Reactive oxygen species (ROS) promote cell death by regulating the activity of various mitogen-activated protein kinases (MAPKs) in ECs. The present study investigated the effects of MAPK inhibitors on cell survival and glutathione (GSH) levels upon H 2 O 2 treatment in calf pulmonary artery ECs (CPAECs). H 2 O 2 treatment inhibited the growth and induced the death of CPAECs, as well as causing GSH depletion and the loss of mitochondrial membrane potential (MMP). While treatment with the MEK or JNK inhibitor impaired the growth of H 2 O 2 -treated CPAECs, treatment with the p38 inhibitor attenuated this inhibition of growth. Additionally, JNK inhibitor treatment increased the proportion of sub-G 1 phase cells in H 2 O 2 -treated CPAECs and further decreased the MMP. However, treatment with a p38 inhibitor reversed the effects of H 2 O 2 treatment on cell growth and the MMP. Similarly, JNK inhibitor treatment further increased, whereas p38 inhibitor treatment decreased, the proportion of GSH-depleted cells in H 2 O 2 -treated CPAECs. Each of the MAPK inhibitors affected cell survival, and ROS or GSH levels differently in H 2 O 2 -untreated, control CPAECs. The data suggest that the exposure of CPAECs to H 2 O 2 caused the cell growth inhibition and cell death through GSH depletion. Furthermore, JNK inhibitor treatment further enhanced, whereas p38 inhibitors attenuated, these effects. Thus, the results of the present study suggest a specific protective role for the p38 inhibitor, and not the JNK inhibitor, against H 2 O 2 -induced cell growth inhibition and cell death.

JAK inhibitors in autoinflammation.

Science.gov (United States)

Hoffman, Hal M; Broderick, Lori

2018-06-11

Interferonopathies are a subset of autoinflammatory disorders with a prominent type I IFN gene signature. Treatment of these patients has been challenging, given the lack of response to common autoinflammatory therapeutics including IL-1 and TNF blockade. JAK inhibitors (Jakinibs) are a family of small-molecule inhibitors that target the JAK/STAT signaling pathway and have shown clinical efficacy, with FDA and European Medicines Agency (EMA) approval for arthritic and myeloproliferative syndromes. Sanchez and colleagues repurposed baricitinib to establish a significant role for JAK inhibition as a novel therapy for patients with interferonopathies, demonstrating the power of translational rare disease research with lifesaving effects.

HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitors

DEFF Research Database (Denmark)

Vanangamudi, Murugesan; Poongavanam, Vasanthanathan; Namasivayam, Vigneshwaran

2017-01-01

BACKGROUND: Design of inhibitors for HIV-1 reverse transcriptase inhibition (HIV-1 RT) is one of the successful chemotherapies for the treatment of HIV infection. Among the inhibitors available for HIV-1 RT, non-nucleoside reverse transcriptase inhibitors (NNRTIs) have shown to be very promising......: The conformation dependent-alignment based (CoMFA and CoMSIA) methods have been proven very successful ligand based strategy in the drug design. Here, CoMFA and CoMSIA studies reported for structurally distinct NNRTIs including thiazolobenzimidazole, dipyridodiazepinone, 1,1,3-trioxo [1,2,4]-thiadiazine...

Inhibitors of Fatty Acid Synthase for Prostate Cancer

Science.gov (United States)

2012-05-01

compounds. For example, numerous classes of acetyl- cholinesterase inhibitors have been developed, m any with fe mtomolar binding affinities (7). This...AD_________________ Award Number: W81XWH-09-1-0204 TITLE: Inhibitors of Fatty Acid Synthase for...CONTRACT NUMBER Inhibitors of Fatty Acid Synthase for Prostate Cancer 5b. GRANT NUMBER W81XWH-09-1-0204 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR

Convergent Akt activation drives acquired EGFR inhibitor resistance in lung cancer

DEFF Research Database (Denmark)

Jacobsen, Kirstine; Bertran-Alamillo, Jordi; Molina, Miguel Angel

2017-01-01

Non-small-cell lung cancer patients with activating epidermal growth factor receptor (EGFR) mutations typically benefit from EGFR tyrosine kinase inhibitor treatment. However, virtually all patients succumb to acquired EGFR tyrosine kinase inhibitor resistance that occurs via diverse mechanisms....... The diversity and unpredictability of EGFR tyrosine kinase inhibitor resistance mechanisms presents a challenge for developing new treatments to overcome EGFR tyrosine kinase inhibitor resistance. Here, we show that Akt activation is a convergent feature of acquired EGFR tyrosine kinase inhibitor resistance......, across a spectrum of diverse, established upstream resistance mechanisms. Combined treatment with an EGFR tyrosine kinase inhibitor and Akt inhibitor causes apoptosis and synergistic growth inhibition in multiple EGFR tyrosine kinase inhibitor-resistant non-small-cell lung cancer models. Moreover...

How Does Influenza A (H1N1 Infection Proceed in Allogeneic Stem Cell Transplantation Recipients?

Directory of Open Access Journals (Sweden)

Sinem Civriz Bozdağ

2012-03-01

Full Text Available Clinical course of H1N1 infection in Allogeneic Hematopoietic Stem Cell Transplantation (AHSCT patients is contraversial. We report three AHSCT patients who were infected with Influenza A/H1N1 infection. All of the patients were diagnosed with different hematological diagnosis and were at different stages of transplantation.All of them were treated with oseltamivir,zanamivir was switched with oseltamivir in one patient. All of the three patients were survived without any complication. Swine flu, can display with different courses and progress with bacterial or other viral infections in immunsupressed patients.

Does plasminogen activator inhibitor-1 drive lymphangiogenesis?

DEFF Research Database (Denmark)

Bruyère, Françoise; Melen-Lamalle, Laurence; Blacher, Silvia

2010-01-01

The purpose of this study is to explore the function of plasminogen activator inhibitor-1 (PAI-1) during pathological lymphangiogenesis. PAI-1, the main physiological inhibitor of plasminogen activators is involved in pathological angiogenesis at least by controlling extracellular proteolysis and...

Nontoxic corrosion inhibitors for N80 steel in hydrochloric acid

Directory of Open Access Journals (Sweden)

M. Yadav

2016-11-01

Full Text Available The purpose of this paper is to evaluate the protective ability of 1-(2-aminoethyl-2-oleylimidazoline (AEOI and 1-(2-oleylamidoethyl-2-oleylimidazoline (OAEOI as corrosion inhibitors for N80 steel in 15% hydrochloric acid, which may find application as eco-friendly corrosion inhibitors in acidizing processes in petroleum industry. Different concentrations of synthesized inhibitors AEOI and OAEOI were added to the test solution (15% HCl and the corrosion inhibition of N80 steel in hydrochloric acid medium containing inhibitors was tested by weight loss, potentiodynamic polarization and AC impedance measurements. Influence of temperature (298–323 K on the inhibition behavior was studied. Surface studies were performed by using FTIR spectra and SEM. Both the inhibitors, AEOI and OAEOI at 150 ppm concentration show maximum efficiency 90.26% and 96.23%, respectively at 298 K in 15% HCl solution. Both the inhibitors act as mixed corrosion inhibitors. The adsorption of the corrosion inhibitors at the surface of N80 steel is the root cause of corrosion inhibition.

Indanones as high-potency reversible inhibitors of monoamine oxidase.

Science.gov (United States)

Mostert, Samantha; Petzer, Anél; Petzer, Jacobus P

2015-05-01

Recent reports document that α-tetralone (3,4-dihydro-2H-naphthalen-1-one) is an appropriate scaffold for the design of high-potency monoamine oxidase (MAO) inhibitors. Based on the structural similarity between α-tetralone and 1-indanone, the present study involved synthesis of 34 1-indanone and related indane derivatives as potential inhibitors of recombinant human MAO-A and MAO-B. The results show that C6-substituted indanones are particularly potent and selective MAO-B inhibitors, with IC50 values ranging from 0.001 to 0.030 μM. C5-Substituted indanone and indane derivatives are comparatively weaker MAO-B inhibitors. Although the 1-indanone and indane derivatives are selective inhibitors of the MAO-B isoform, a number of homologues are also potent MAO-A inhibitors, with three homologues possessing IC50 values 1-indanone as a reversible MAO inhibitor with a competitive mode of inhibition. It may be concluded that 1-indanones are promising leads for the design of therapies for neurodegenerative and neuropsychiatric disorders such as Parkinson's disease and depression. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Insights into the molecular evolution of peptidase inhibitors in arthropods.

Science.gov (United States)

Alonso, Joaquin; Martinez, Manuel

2017-01-01

Peptidase inhibitors are key proteins involved in the control of peptidases. In arthropods, peptidase inhibitors modulate the activity of peptidases involved in endogenous physiological processes and peptidases of the organisms with which they interact. Exploring available arthropod genomic sequences is a powerful way to obtain the repertoire of peptidase inhibitors in every arthropod species and to understand the evolutionary mechanisms involved in the diversification of this kind of proteins. A genomic comparative analysis of peptidase inhibitors in species belonging to different arthropod taxonomic groups was performed. The results point out: i) species or clade-specific presence is shown for several families of peptidase inhibitors; ii) multidomain peptidase inhibitors are commonly found in many peptidase inhibitor families; iii) several families have a wide range of members in different arthropod species; iv) several peptidase inhibitor families show species-specific (or clade-specific) gene family expansions; v) functional divergence may be assumed for particular clades; vi) passive expansions may be used by natural selection to fix adaptations. In conclusion, conservation and divergence of duplicated genes and the potential recruitment as peptidase inhibitors of proteins from other families are the main mechanisms used by arthropods to fix diversity. This diversity would be associated to the control of target peptidases and, as consequence, to adapt to specific environments.

ROCK inhibitors in ocular disease

Directory of Open Access Journals (Sweden)

Eva Halasz

2016-12-01

Full Text Available Rho kinases (ROCKs have a crucial role in actin-cytoskeletal reorganization and thus are involved in broad aspects of cell motility, from smooth muscle contraction to neurite outgrowth. The first marketed ROCK inhibitor, called fasudil, has been used safely for treatment of cerebral vasospasm since 1995 in Japan. During the succeeding decades ROCK inhibitors have been applied in many pathological conditions from central nervous system disorders to cardiovascular disease as potential therapeutic agents or experimental tools to help understand the underlying (pathomechanisms. In 2014, a fasudil derivate named ripasudil was accepted for clinical use in glaucoma and ocular hypertension. Since ROCK kinases are widely expressed in ocular tissues, they have been implicated in the pathology of many ocular conditions such as corneal dysfunction, glaucoma, cataract, diabetic retinopathy, age-related macular degeneration, and retinal detachment. This paper aims to provide an overview of the most recent status/application of ROCK inhibitors in the field of eye disease.

SGLT-2 Inhibitors and Cardiovascular Risk

DEFF Research Database (Denmark)

Cavender, Matthew A; Norhammar, Anna; Birkeland, Kåre I

2018-01-01

BACKGROUND: Prior studies found patients treated with sodium-glucose co-transporter-2 inhibitors (SGLT-2i) had lower rates of death and heart failure (HF). Whether the benefits of SGLT-2i vary based upon the presence of cardiovascular disease (CVD) is unknown. OBJECTIVES: This study sought...... to determine the association between initiation of SGLT-2i therapy and HF or death in patients with and without CVD. METHODS: The CVD-REAL (Comparative Effectiveness of Cardiovascular Outcomes in New Users of SGLT-2 Inhibitors) study was a multinational, observational study in which adults with type 2 diabetes...... evidence regarding the benefit of SGLT-2i in patients without established CVD. (Comparative Effectiveness of Cardiovascular Outcomes in New Users of SGLT-2 Inhibitors [CVD-REAL]; NCT02993614)....

Protein C Inhibitor-A Novel Antimicrobial Agent

NARCIS (Netherlands)

Malmström, E.; Mörgelin, M.; Malmsten, M.; Johansson, L.; Norrby-Teglund, A.; Shannon, O.; Schmidtchen, A.; Meijers, J.C.M.; Herwald, H.

2009-01-01

Protein C inhibitor (PCI) is a heparin-binding serine proteinase inhibitor belonging to the family of serpin proteins. Here we describe that PCI exerts broad antimicrobial activity against bacterial pathogens. This ability is mediated by the interaction of PCI with lipid membranes, which

Electrochemical Behaviour of Environmentally Friendly Inhibitor of ...

African Journals Online (AJOL)

Electrochemical Behaviour of Environmentally Friendly Inhibitor of Aloe Secundiflora Extract in Corrosion Control of Carbon Steel in Soft Water Media. ... The investigation was performed at different inhibitor concentrations under static and dynamic conditions using a Rotating Disk Electrode (RDE). The impedance and ...

Identification of catechols as histone-lysine demethylase inhibitors

DEFF Research Database (Denmark)

Nielsen, Anders L; Kristensen, Line H; Stephansen, Karen B

2012-01-01

Identification of inhibitors of histone-lysine demethylase (HDM) enzymes is important because of their involvement in the development of cancer. An ELISA-based assay was developed for identification of inhibitors of the HDM KDM4C in a natural products library. Based on one of the hits with affinity...... in the low µM range (1, a catechol), a subset of structurally related compounds was selected and tested against a panel of HDMs. In this subset, two inhibitors (2 and 10) had comparable affinities towards KDM4C and KDM6A but no effect on PHF8. One inhibitor restored H3K9me3 levels in KDM4C transfected U2-OS...

Radioimmunoassay of influenza A virus haemagglutinin. I

International Nuclear Information System (INIS)

Russ, G.; Styk, B.; Polakova, K.

1978-01-01

Haemagglutinin released from influenza A virus recombinant MRC11 [antigenically identical to the strain A/Port Chalmers/1/73 (H3N2)] by bromelain treatment and purified by rate zonal centrifugation (further on B-HA) was examined for possible contamination by neuraminidase. Specific enzymatic activities of the MRC11 virus and the B-HA respectively showed that B-HA contained less than 0.1% of enzymatically active neuraminidase originally present in the virus. Gel double diffusion tests, specificities of rabbit antisera induced by B-HA as well as radioimmunoprecipitation experiments demonstrated that B-HA was devoid of any antigenically active neuraminidase. Precipitation of 125 I-labelled B-HA with antisera to influenza virus recombinants with N2 neuraminidase was evidently caused by antibodies to host antigenic determinant(s) present in these sera. As for purity and radioimmunoprecipitation properties, B-HA is quite suitable for radioimmunoassay experiments. (author)

Cardiovascular effects of sodium glucose cotransporter 2 inhibitors

Directory of Open Access Journals (Sweden)

Santos Cavaiola T

2018-04-01

Full Text Available Tricia Santos Cavaiola, Jeremy Pettus Division of Endocrinology and Metabolism, University of California San Diego, San Diego, CA, USA Abstract: As the first cardiovascular (CV outcome trial of a glucose-lowering agent to demonstrate a reduction in the risk of CV events in patients with type 2 diabetes mellitus (T2DM, the EMPAgliflozin Removal of Excess Glucose: Cardiovascular OUTCOME Event Trial in Type 2 Diabetes Mellitus Patients (EMPA-REG OUTCOME® trial, which investigated the sodium glucose cotransporter 2 (SGLT2 inhibitor empagliflozin, has generated great interest among health care professionals. CV outcomes data for another SGLT2 inhibitor, canagliflozin, have been published recently in the CANagliflozin CardioVascular Assessment Study (CANVAS Program, as have CV data from the retrospective real-world study Comparative Effectiveness of Cardiovascular Outcomes in New Users of Sodium-Glucose Cotransporter-2 Inhibitors (CVD-REAL, which compared SGLT2 inhibitors with other classes of glucose-lowering drugs. This review discusses the results of these three studies and, with a focus on EMPA-REG OUTCOME, examines the possible mechanisms by which SGLT2 inhibitors may reduce CV risk in patients with T2DM. Keywords: canagliflozin, cardiovascular outcomes, dapagliflozin, empagliflozin, mechanisms, sodium glucose cotransporter 2 inhibitors

Synthesis and Application of Pyrrolidone-containing Shale Inhibitors

Science.gov (United States)

Liu, Yonggui; Hou, Jie; Zhang, Yang; Yan, Jing; Song, Tao; Xu, Yongjun

2018-03-01

New generation polyamine inhibitors are amino-terminated polyethers with excellent inhibiting capabilities; they play a key role in borehole stabilization and reservoir protection. However, polyamine inhibitors are limited by their poor thermal stability, which can be attributed to the presence of ether bonds in their molecular structures. We propose a three-step synthesis approach fora novel pyrrolidone-containing polyamine inhibitor (DYNP) by introducing N-vinyl-2-pyrrolidone (NVP) on divinyloxyethane. This polyamine inhibitor exhibits an optimized molecular structure and has enhanced heat resistance. Characterizations by infrared (IR) spectroscopy and evaluation tests demonstrate several advantages of DYNP inhibitors, including excellent inhibiting capability (superior to similar materials such as polyamines), improved heat resistance (reasonable stability at temperatures up to 240°C), and good compatibility with both fresh water and salt water drilling fluids. These can be attributed to the presence of considerable amounts of amino groups in the repeating unit of DYNP molecules. The DYNP inhibitor was applied in over 20 boreholes in tight oil blocks in Daqing Oilfield to relieve hydration of formations with high shale contents. For instance, drilling in the 2033.5m horizontal section of Dragon 2 borehole was smooth, with a borehole diameter expansion ratio below 10%.

Inhibitor specificity of recombinant and endogenous caspase-9.

Science.gov (United States)

Ryan, Ciara A; Stennicke, Henning R; Nava, Victor E; Burch, Jennifer B; Hardwick, J Marie; Salvesen, Guy S

2002-01-01

Apoptosis triggered through the intrinsic pathway by radiation and anti-neoplastic drugs is initiated by the activation of caspase-9. To elucidate control mechanisms in this pathway we used a range of synthetic and natural reagents. The inhibitory potency of acetyl-Asp-Glu-Val-Asp-aldehyde ('Ac-DEVD-CHO'), benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone ('Z-VAD-FMK') and the endogenous caspase inhibitor X-chromosome-linked inhibitor of apoptosis protein ('XIAP') against recombinant caspase-9 were predictive of the efficacy of these compounds in a cell-free system. However, the viral proteins CrmA and p35, although potent inhibitors of recombinant caspase-9, had almost no ability to block caspase-9 in this system. These findings were also mirrored in cell expression studies. We hypothesize that the viral inhibitors CrmA and p35 are excluded from reacting productively with the natural form of active caspase-9 in vivo, making the potency of inhibitors highly context-dependent. This is supported by survival data from a mouse model of apoptosis driven by Sindbis virus expressing either p35 or a catalytic mutant of caspase-9. These results consolidate previous findings that CrmA is a potent inhibitor of caspase-9 in vitro, yet fails to block caspase-9-mediated cell death. PMID:12067274

Classification of Breast Cancer Resistant Protein (BCRP) Inhibitors and Non-Inhibitors Using Machine Learning Approaches.

Science.gov (United States)

Belekar, Vilas; Lingineni, Karthik; Garg, Prabha

2015-01-01

The breast cancer resistant protein (BCRP) is an important transporter and its inhibitors play an important role in cancer treatment by improving the oral bioavailability as well as blood brain barrier (BBB) permeability of anticancer drugs. In this work, a computational model was developed to predict the compounds as BCRP inhibitors or non-inhibitors. Various machine learning approaches like, support vector machine (SVM), k-nearest neighbor (k-NN) and artificial neural network (ANN) were used to develop the models. The Matthews correlation coefficients (MCC) of developed models using ANN, k-NN and SVM are 0.67, 0.71 and 0.77, and prediction accuracies are 85.2%, 88.3% and 90.8% respectively. The developed models were tested with a test set of 99 compounds and further validated with external set of 98 compounds. Distribution plot analysis and various machine learning models were also developed based on druglikeness descriptors. Applicability domain is used to check the prediction reliability of the new molecules.

The effects of residual platelets in plasma on plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays

NARCIS (Netherlands)

M. Pieters (Marlien); S.A. Barnard (Sunelle A.); D.T. Loots (Du Toit); D.C. Rijken (Dingeman)

2017-01-01

textabstractDue to controversial evidence in the literature pertaining to the activity of plasminogen activator inhibitor-1 in platelets, we examined the effects of residual platelets present in plasma (a potential pre-analytical variable) on various plasminogen activator inhibitor-1 and plasminogen

Pathophysiological significance and therapeutic applications of snake venom protease inhibitors.

Science.gov (United States)

Thakur, Rupamoni; Mukherjee, Ashis K

2017-06-01

Protease inhibitors are important constituents of snake venom and play important roles in the pathophysiology of snakebite. Recently, research on snake venom protease inhibitors has provided valuable information to decipher the molecular details of various biological processes and offer insight for the development of some therapeutically important molecules from snake venom. The process of blood coagulation and fibrinolysis, in addition to affecting platelet function, are well known as the major targets of several snake venom protease inhibitors. This review summarizes the structure-functional aspects of snake venom protease inhibitors that have been described to date. Because diverse biological functions have been demonstrated by protease inhibitors, a comparative overview of their pharmacological and pathophysiological properties is also highlighted. In addition, since most snake venom protease inhibitors are non-toxic on their own, this review evaluates the different roles of individual protease inhibitors that could lead to the identification of drug candidates and diagnostic molecules. Copyright © 2017 Elsevier Ltd. All rights reserved.

New test for oil soluble/water dispersible gas pipeline inhibitors

Energy Technology Data Exchange (ETDEWEB)

Stegmann, D.W.; Asperger, R.G.

1987-01-01

The wheel test provides good mixing of the condensate and water phases, the coupons are exposed to both phases. Therefore, the wheel test cannot distinguish between inhibitors that need continuous mixing of the these phases to maintain a water dispersion of the inhibitor and inhibitors that will self disperse into the water. This concept becomes important for pipelines in stratified flow where the water can settle out. In these cases with low turbulence, the inhibitor must self disperse into the water to be effective. The paper describes a test method to measure the effectiveness of an inhibitor and its ability to self disperse. The effectiveness of several inhibitors as predicted by the new test method is discussed relative to data from the wheel test and breaker tests. Field performance of these inhibitors in a gas gathering line, with liquids in stratified flow, are cities and compared with the results of the various laboratory tests.

Aromatase inhibitors in men: effects and therapeutic options

Directory of Open Access Journals (Sweden)

de Jong Frank H

2011-06-01

Full Text Available Abstract Aromatase inhibitors effectively delay epiphysial maturation in boys and improve testosterone levels in adult men Therefore, aromatase inhibitors may be used to increase adult height in boys with gonadotropin-independent precocious puberty, idiopathic short stature and constitutional delay of puberty. Long-term efficacy and safety of the use of aromatase inhibitors has not yet been established in males, however, and their routine use is therefore not yet recommended.

Urinary trypsin inhibitor - an experimental and clinical study

International Nuclear Information System (INIS)

Berling, B.M.

1991-01-01

The urinary trypsin inhibitor (UTI) is an acid stable proteinase inhibitor present in blood and urine. It was purified from urine using affinity chromatography, ion exchange chromatography and gel filtration. Two forms of UTI were present in urine, A and B. A radioimmunoassay for measurement of UTI in urine and plasma was performed. The normal level of UTI in plasma and serum was about 2 mg/l. The normal excretion in urine was about 8 mg per 24 hours. The plasma and urine levels of UTI were studied in patients with acute pancreatitis and in patients undergoing cholecystectomy. Uremic patients had a marked increase of UTI in plasma compatible with decreased glomerular filtration. In samples from healthy persons as well as from patients only inhibitor A was found. Inhibitor B has recently been renamed bikunin because of its two Kunitz-type inhibiting domains. Inhibitor A might be called tetrakunin. Radioactively labeled UTI (inhibitor A) was injected intravenously in three male volunteers. The plasma half-life of 125 I UTI was 2 hours. Free biologically active inhibitor was found in the urine during the first four hours after injection. The organ distribution of intravenously injected 125 I UTI was studied in rats. Fifteen minutes after injection the major part of the radioactivity was found in the kidneys, suggesting that the kidneys are the primary site of UTI metabolism. Using immunohistochemical techniques UTI was found in the proximal tubules of the normal human kidney further indicating the tubular reabsorption and methabolisms of UTI

Azidoblebbistatin, a photoreactive myosin inhibitor

Science.gov (United States)

Képiró, Miklós; Várkuti, Boglárka H.; Bodor, Andrea; Hegyi, György; Drahos, László; Kovács, Mihály; Málnási-Csizmadia, András

2012-01-01

Photoreactive compounds are important tools in life sciences that allow precisely timed covalent crosslinking of ligands and targets. Using a unique technique we have synthesized azidoblebbistatin, which is a derivative of blebbistatin, the most widely used myosin inhibitor. Without UV irradiation azidoblebbistatin exhibits identical inhibitory properties to those of blebbistatin. Using UV irradiation, azidoblebbistatin can be covalently crosslinked to myosin, which greatly enhances its in vitro and in vivo effectiveness. Photo-crosslinking also eliminates limitations associated with the relatively low myosin affinity and water solubility of blebbistatin. The wavelength used for photo-crosslinking is not toxic for cells and tissues, which confers a great advantage in in vivo tests. Because the crosslink results in an irreversible association of the inhibitor to myosin and the irradiation eliminates the residual activity of unbound inhibitor molecules, azidoblebbistatin has a great potential to become a highly effective tool in both structural studies of actomyosin contractility and the investigation of cellular and physiological functions of myosin II. We used azidoblebbistatin to identify previously unknown low-affinity targets of the inhibitor (EC50 ≥ 50 μM) in Dictyostelium discoideum, while the strongest interactant was found to be myosin II (EC50 = 5 μM). Our results demonstrate that azidoblebbistatin, and potentially other azidated drugs, can become highly useful tools for the identification of strong- and weak-binding cellular targets and the determination of the apparent binding affinities in in vivo conditions. PMID:22647605

Predicting the Performance of Organic Corrosion Inhibitors

Directory of Open Access Journals (Sweden)

David A. Winkler

2017-12-01

Full Text Available The withdrawal of effective but toxic corrosion inhibitors has provided an impetus for the discovery of new, benign organic compounds to fill that role. Concurrently, developments in the high-throughput synthesis of organic compounds, the establishment of large libraries of available chemicals, accelerated corrosion inhibition testing technologies, and the increased capability of machine learning methods have made discovery of new corrosion inhibitors much faster and cheaper than it used to be. We summarize these technical developments in the corrosion inhibition field and describe how data-driven machine learning methods can generate models linking molecular properties to corrosion inhibition that can be used to predict the performance of materials not yet synthesized or tested. We briefly summarize the literature on quantitative structure–property relationships models of small organic molecule corrosion inhibitors. The success of these models provides a paradigm for rapid discovery of novel, effective corrosion inhibitors for a range of metals and alloys in diverse environments.

SGLT2 Inhibitors and the Diabetic Kidney.

Science.gov (United States)

Fioretto, Paola; Zambon, Alberto; Rossato, Marco; Busetto, Luca; Vettor, Roberto

2016-08-01

Diabetic nephropathy (DN) is the most common cause of end-stage renal disease worldwide. Blood glucose and blood pressure control reduce the risk of developing this complication; however, once DN is established, it is only possible to slow progression. Sodium-glucose cotransporter 2 (SGLT2) inhibitors, the most recent glucose-lowering oral agents, may have the potential to exert nephroprotection not only through improving glycemic control but also through glucose-independent effects, such as blood pressure-lowering and direct renal effects. It is important to consider, however, that in patients with impaired renal function, given their mode of action, SGLT2 inhibitors are less effective in lowering blood glucose. In patients with high cardiovascular risk, the SGLT2 inhibitor empagliflozin lowered the rate of cardiovascular events, especially cardiovascular death, and substantially reduced important renal outcomes. Such benefits on DN could derive from effects beyond glycemia. Glomerular hyperfiltration is a potential risk factor for DN. In addition to the activation of the renin-angiotensin-aldosterone system, renal tubular factors, including SGLT2, contribute to glomerular hyperfiltration in diabetes. SGLT2 inhibitors reduce sodium reabsorption in the proximal tubule, causing, through tubuloglomerular feedback, afferent arteriole vasoconstriction and reduction in hyperfiltration. Experimental studies showed that SGLT2 inhibitors reduced hyperfiltration and decreased inflammatory and fibrotic responses of proximal tubular cells. SGLT2 inhibitors reduced glomerular hyperfiltration in patients with type 1 diabetes, and in patients with type 2 diabetes, they caused transient acute reductions in glomerular filtration rate, followed by a progressive recovery and stabilization of renal function. Interestingly, recent studies consistently demonstrated a reduction in albuminuria. Although these data are promising, only dedicated renal outcome trials will clarify whether

Inhibitor development and mortality in non-severe hemophilia A.

Science.gov (United States)

Eckhardt, C L; Loomans, J I; van Velzen, A S; Peters, M; Mauser-Bunschoten, E P; Schwaab, R; Mazzucconi, M G; Tagliaferri, A; Siegmund, B; Reitter-Pfoertner, S E; van der Bom, J G; Fijnvandraat, K

2015-07-01

The life expectancy of non-severe hemophilia A (HA) patients equals the life expectancy of the non-hemophilic population. However, data on the effect of inhibitor development on mortality and on hemophilia-related causes of death are scarce. The development of neutralizing factor VIII antibodies in non-severe HA patients may dramatically change their clinical outcome due to severe bleeding complications. We assessed the association between the occurrence of inhibitors and mortality in patients with non-severe HA. In this retrospective cohort study, clinical data and vital status were collected for 2709 non-severe HA patients (107 with inhibitors) who were treated between 1980 and 2011 in 34 European and Australian centers. Mortality rates for patients with and without inhibitors were compared. During 64,200 patient-years of follow-up, 148 patients died (mortality rate, 2.30 per 1000 person-years; 95% confidence interval (CI), 1.96-2.70) at a median age of 64 years (interquartile range [IQR], 49-76). In 62 patients (42%) the cause of death was hemophilia related. Sixteen inhibitor patients died at a median age of 71 years (IQR, 60-81). In ten patients the inhibitor was present at time of death; seven of them died of severe bleeding complications. The all-cause mortality rate in inhibitor patients was > 5 times increased compared with that for those without inhibitors (age-adjusted mortality rate ratio, 5.6). Inhibitor development in non-severe hemophilia is associated with increased mortality. High rates of hemophilia-related mortality in this study indicate that non-severe hemophilia is not mild at all and stress the importance of close follow-up for these patients. © 2015 International Society on Thrombosis and Haemostasis.

New synthetic thrombin inhibitors: molecular design and experimental verification.

Science.gov (United States)

Sinauridze, Elena I; Romanov, Alexey N; Gribkova, Irina V; Kondakova, Olga A; Surov, Stepan S; Gorbatenko, Aleksander S; Butylin, Andrey A; Monakov, Mikhail Yu; Bogolyubov, Alexey A; Kuznetsov, Yuryi V; Sulimov, Vladimir B; Ataullakhanov, Fazoyl I

2011-01-01

The development of new anticoagulants is an important goal for the improvement of thromboses treatments. The design, synthesis and experimental testing of new safe and effective small molecule direct thrombin inhibitors for intravenous administration. Computer-aided molecular design of new thrombin inhibitors was performed using our original docking program SOL, which is based on the genetic algorithm of global energy minimization in the framework of a Merck Molecular Force Field. This program takes into account the effects of solvent. The designed molecules with the best scoring functions (calculated binding energies) were synthesized and their thrombin inhibitory activity evaluated experimentally in vitro using a chromogenic substrate in a buffer system and using a thrombin generation test in isolated plasma and in vivo using the newly developed model of hemodilution-induced hypercoagulation in rats. The acute toxicities of the most promising new thrombin inhibitors were evaluated in mice, and their stabilities in aqueous solutions were measured. New compounds that are both effective direct thrombin inhibitors (the best K(I) was 50) in the thrombin generation assay of approximately 100 nM) were discovered. These compounds contain one of the following new residues as the basic fragment: isothiuronium, 4-aminopyridinium, or 2-aminothiazolinium. LD(50) values for the best new inhibitors ranged from 166.7 to >1111.1 mg/kg. A plasma-substituting solution supplemented with one of the new inhibitors prevented hypercoagulation in the rat model of hemodilution-induced hypercoagulation. Activities of the best new inhibitors in physiological saline (1 µM solutions) were stable after sterilization by autoclaving, and the inhibitors remained stable at long-term storage over more than 1.5 years at room temperature and at 4°C. The high efficacy, stability and low acute toxicity reveal that the inhibitors that were developed may be promising for potential medical applications.

Wheat Subtilisin/Chymotrypsin Inhibitor (WSCI) as a scaffold for novel serine protease inhibitors with a given specificity.

Science.gov (United States)

Tedeschi, Francesca; Di Maro, Antimo; Facchiano, Angelo; Costantini, Susan; Chambery, Angela; Bruni, Natalia; Capuzzi, Valeria; Ficca, Anna Grazia; Poerio, Elia

2012-10-30

WSCI (Wheat Subtilisin/Chymotrypsin Inhibitor) is a small protein belonging to the Potato inhibitor I family exhibiting a high content of essential amino acid. In addition to bacterial subtilisins and mammalian chymotrypsins, WSCI inhibits chymotrypsin-like activities isolated from digestive traits of a number of insect larvae. In vivo, as suggested for many plant proteinase inhibitors, WSCI seems to play a role of natural defence against attacks of pests and pathogens. The functional region of WSCI, containing the inhibitor reactive site (Met48-Glu49), corresponds to an extended flexible loop (Val42-Asp53) whose architecture is somehow stabilized by a number of secondary interactions established with a small β-sheet located underneath. The aim of this study was to employ a WSCI molecule as a stable scaffold to obtain recombinant inhibitors with new acquired anti-proteinase activity or, alternatively, inactive WSCI variants. A gene sequence coding for the native WSCI, along with genes coding for muteins with different specficities, could be exploited to obtain transformed non-food use plants with improved insect resistance. On the other hand, the genetic transformation of cereal plants over-expressing inactive WSCI muteins could represent a possible strategy to improve the nutritional quality of cereal-based foods, without risk of interference with human or animal digestive enzymes. Here, we described the characterization of four muteins containing single/multiple amino acid substitutions at the WSCI reactive site and/or at its proximity. Modalities of interaction of these muteins with proteinases (subtilisin, trypsin and chymotrypsin) were investigated by time course hydrolysis and molecular simulations studies.

Cardiovascular effects of sodium glucose cotransporter 2 inhibitors

Science.gov (United States)

Cavaiola, Tricia Santos; Pettus, Jeremy

2018-01-01

As the first cardiovascular (CV) outcome trial of a glucose-lowering agent to demonstrate a reduction in the risk of CV events in patients with type 2 diabetes mellitus (T2DM), the EMPAgliflozin Removal of Excess Glucose: Cardiovascular OUTCOME Event Trial in Type 2 Diabetes Mellitus Patients (EMPA-REG OUTCOME®) trial, which investigated the sodium glucose cotransporter 2 (SGLT2) inhibitor empagliflozin, has generated great interest among health care professionals. CV outcomes data for another SGLT2 inhibitor, canagliflozin, have been published recently in the CANagliflozin CardioVascular Assessment Study (CANVAS) Program, as have CV data from the retrospective real-world study Comparative Effectiveness of Cardiovascular Outcomes in New Users of Sodium-Glucose Cotransporter-2 Inhibitors (CVD-REAL), which compared SGLT2 inhibitors with other classes of glucose-lowering drugs. This review discusses the results of these three studies and, with a focus on EMPA-REG OUTCOME, examines the possible mechanisms by which SGLT2 inhibitors may reduce CV risk in patients with T2DM. PMID:29695924

Comparison between SGLT2 inhibitors and DPP4 inhibitors added to insulin therapy in type 2 diabetes: a systematic review with indirect comparison meta-analysis.

Science.gov (United States)

Min, Se Hee; Yoon, Jeong-Hwa; Hahn, Seokyung; Cho, Young Min

2017-01-01

Both sodium glucose cotransporter 2 (SGLT2) inhibitors and dipeptidyl peptidase-4 (DPP4) inhibitors can be used to treat patients with type 2 diabetes mellitus (T2DM) that is inadequately controlled with insulin therapy, and yet there has been no direct comparison of these two inhibitors. We searched MEDLINE, EMBASE, LILACS, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov through June 2015. Randomized controlled trials published in English that compare SGLT2 inhibitor plus insulin (SGLT2i/INS) with placebo plus insulin or DPP4 inhibitor plus insulin (DPP4i/INS) with placebo plus insulin in patients with T2DM were selected. Data on the study characteristics, efficacy and safety outcomes were extracted. We compared the efficacy and safety between SGLT2i/INS and DPP4i/INS indirectly with covariates adjustment. Risk of potential bias was assessed. Fourteen eligible randomized controlled trials comprising 6980 patients were included (five SGLT2 inhibitor studies and nine DPP4 inhibitor studies). Covariate-adjusted indirect comparison using meta-regression analyses revealed that SGLT2i/INS achieved greater reduction in HbA 1c [weighted mean difference (WMD) -0.24%, 95% confidence interval (CI) -0.43 to -0.05%], fasting plasma glucose (WMD -18.0 mg/dL, 95% CI -28.5 to -7.6 mg/dL) and body weight (WMD -2.38 kg, 95% CI -3.18 to -1.58 kg) from baseline than DPP4i/INS without increasing the risk of hypoglycaemia (relative risks 1.19, 95% CI 0.78 to 1.82). Sodium glucose cotransporter 2 inhibitors achieved better glycaemic control and greater weight reduction than DPP4 inhibitors without increasing the risk of hypoglycaemia in patients with T2DM that is inadequately controlled with insulin. There has been no direct comparison of SGLT2 inhibitors and DPP4 inhibitors in patients with T2DM inadequately controlled with insulin therapy. In this study, we performed indirect meta-analysis comparing SGLT2 inhibitors and DPP4 inhibitors added to insulin

FAITH – Fast Assembly Inhibitor Test for HIV

Energy Technology Data Exchange (ETDEWEB)

Hadravová, Romana [Institute of Organic Chemistry and Biochemistry IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Prague (Czech Republic); Rumlová, Michaela, E-mail: michaela.rumlova@vscht.cz [Institute of Organic Chemistry and Biochemistry IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Prague (Czech Republic); Department of Biotechnology, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague (Czech Republic); Ruml, Tomáš, E-mail: tomas.ruml@vscht.cz [Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Technická 3, 166 28 Prague (Czech Republic)

2015-12-15

Due to the high number of drug-resistant HIV-1 mutants generated by highly active antiretroviral therapy (HAART), there is continuing demand for new types of inhibitors. Both the assembly of the Gag polyprotein into immature and mature HIV-1 particles are attractive candidates for the blocking of the retroviral life cycle. Currently, no therapeutically-used assembly inhibitor is available. One possible explanation is the lack of a reliable and simple assembly inhibitor screening method. To identify compounds potentially inhibiting the formation of both types of HIV-1 particles, we developed a new fluorescent high-throughput screening assay. This assay is based on the quantification of the assembly efficiency in vitro in a 96-well plate format. The key components of the assay are HIV-1 Gag-derived proteins and a dual-labelled oligonucleotide, which emits fluorescence only when the assembly of retroviral particles is inhibited. The method was validated using three (CAI, BM2, PF74) reported assembly inhibitors. - Highlights: • Allows screening of assembly inhibitors of both mature and immature HIV-1 particles. • Based on Gag-derived proteins with CA in mature or immature conformation. • Simple and sensitive method suitable for high-throughput screening of inhibitors. • Unlike in other HIV assembly methods, works under physiological conditions. • No washing steps are necessary.

FAITH – Fast Assembly Inhibitor Test for HIV

International Nuclear Information System (INIS)

Hadravová, Romana; Rumlová, Michaela; Ruml, Tomáš

2015-01-01

Due to the high number of drug-resistant HIV-1 mutants generated by highly active antiretroviral therapy (HAART), there is continuing demand for new types of inhibitors. Both the assembly of the Gag polyprotein into immature and mature HIV-1 particles are attractive candidates for the blocking of the retroviral life cycle. Currently, no therapeutically-used assembly inhibitor is available. One possible explanation is the lack of a reliable and simple assembly inhibitor screening method. To identify compounds potentially inhibiting the formation of both types of HIV-1 particles, we developed a new fluorescent high-throughput screening assay. This assay is based on the quantification of the assembly efficiency in vitro in a 96-well plate format. The key components of the assay are HIV-1 Gag-derived proteins and a dual-labelled oligonucleotide, which emits fluorescence only when the assembly of retroviral particles is inhibited. The method was validated using three (CAI, BM2, PF74) reported assembly inhibitors. - Highlights: • Allows screening of assembly inhibitors of both mature and immature HIV-1 particles. • Based on Gag-derived proteins with CA in mature or immature conformation. • Simple and sensitive method suitable for high-throughput screening of inhibitors. • Unlike in other HIV assembly methods, works under physiological conditions. • No washing steps are necessary.

Rho-associated kinase inhibitors: a novel glaucoma therapy.

Science.gov (United States)

Inoue, Toshihiro; Tanihara, Hidenobu

2013-11-01

The rho-associated kinase (ROCK) signaling pathway is activated via secreted bioactive molecules or via integrin activation after extracellular matrix binding. These lead to polymerization of actin stress fibers and formation of focal adhesions. Accumulating evidence suggests that actin cytoskeleton-modulating signals are involved in aqueous outflow regulation. Aqueous humor contains various biologically active factors, some of which are elevated in glaucomatous eyes. These factors affect aqueous outflow, in part, through ROCK signaling modulation. Various drugs acting on the cytoskeleton have also been shown to increase aqueous outflow by acting directly on outflow tissue. In vivo animal studies have shown that the trabecular meshwork (TM) actin cytoskeleton in glaucomatous eyes is more disorganized and more randomly oriented than in non-glaucomatous control eyes. In a previous study, we introduced ROCK inhibitors as a potential glaucoma therapy by showing that a selective ROCK inhibitor significantly lowered rabbit IOP. Rho-associated kinase inhibitors directly affect the TM and Schlemm's canal (SC), differing from the target sight of other glaucoma drugs. The TM is affected earlier and more strongly than ciliary muscle cells by ROCK inhibitors, largely because of pharmacological affinity differences stemming from regulatory mechanisms. Additionally, ROCK inhibitors disrupt tight junctions, result in F-actin depolymerization, and modulate intracellular calcium level, effectively increasing SC-cell monolayer permeability. Perfusion of an enucleated eye with a ROCK inhibitor resulted in wider empty spaces in the juxtacanalicular (JCT) area and more giant vacuoles in the endothelial cells of SC, while the endothelial lining of SC was intact. Interestingly, ROCK inhibitors also increase retinal blood flow by relaxing vascular smooth muscle cells, directly protecting neurons against various stresses, while promoting wound healing. These additional effects may help

RENAL SAFETY OF PROTON PUMP INHIBITORS

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A. I. Dyadyk

2017-01-01

Full Text Available Proton pump inhibitors are a widely used in clinical practice, and are taken by millions of patients around the world for a long time. While proton pump inhibitors are well-tolerated class of drugs, the number of publications has been raised about adverse renal effects, specially their association with acute tubulointerstitial nephritis. It is one of the leading causes of acute renal injury and have catastrophic long-term consequences called chronic kidney disease. In this review, we consider epidemiology, pathogenesis, diagnostic criteria (including biopsy and morphological pattern, clinical manifestations and treatment of proton pump inhibitors-induced acute tubulointerstitial nephritis. A subclinical course without classical manifestations of a cell-mediated hypersensitivity reaction (fever, skin rash, eosinophilia, arthralgia is characteristic of acute tubulointerstitial nephritis. Increased serum creatinine, decreased glomerular filtration rate, electrolyte disorders, pathological changes in urine tests are not highly specific indicators, but allow to suspect the development of acute tubulointerstitial nephritis. The “gold” standard of diagnosis is the intravital morphological examination of the kidney tissue. Timely diagnosis and immediate discontinuation of the potentially causative drug is the mainstay of therapy and the first necessary step in the early management of suspected or biopsy-proven drug-induced acute tubulointerstitial nephritis. The usage of proton pump inhibitors should be performed only on strict indications with optimal duration of treatment and careful monitoring of kidney function. Multiple comorbidities (older age, heart failure, diabetes, cirrhosis, chronic kidney disease, hypovolemia increase potential nephrotoxicity. Awareness of this iatrogenic complication will improve diagnosis of proton pump inhibitors-induced acute tubulointerstitial nephritis by multidisciplinary specialists and increase the possibility

Recombinant infectious bronchitis virus (IBV) H120 vaccine strain expressing the hemagglutinin-neuraminidase (HN) protein of Newcastle disease virus (NDV) protects chickens against IBV and NDV challenge.

Science.gov (United States)

Yang, Xin; Zhou, Yingshun; Li, Jianan; Fu, Li; Ji, Gaosheng; Zeng, Fanya; Zhou, Long; Gao, Wenqian; Wang, Hongning

2016-05-01

Infectious bronchitis (IB) and Newcastle disease (ND) are common viral diseases of chickens, which are caused by infectious bronchitis virus (IBV) and Newcastle disease virus (NDV), respectively. Vaccination with live attenuated strains of IBV-H120 and NDV-LaSota are important for the control of IB and ND. However, conventional live attenuated vaccines are expensive and result in the inability to differentiate between infected and vaccinated chickens. Therefore, there is an urgent need to develop new efficacious vaccines. In this study, using a previously established reverse genetics system, we generated a recombinant IBV virus based on the IBV H120 vaccine strain expressing the haemagglutinin-neuraminidase (HN) protein of NDV. The recombinant virus, R-H120-HN/5a, exhibited growth dynamics, pathogenicity and viral titers that were similar to those of the parental IBV H120, but it had acquired hemagglutination activity from NDV. Vaccination of SPF chickens with the R-H120-HN/5a virus induced a humoral response at a level comparable to that of the LaSota/H120 commercial bivalent vaccine and provided significant protection against challenge with virulent IBV and NDV. In summary, the results of this study indicate that the IBV H120 strain could serve as an effective tool for designing vaccines against IB and other infectious diseases, and the generation of IBV R-H120-HN/5a provides a solid foundation for the development of an effective bivalent vaccine against IBV and NDV.

Hospital triage system for adult patients using an influenza-like illness scoring system during the 2009 pandemic--Mexico.

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Eduardo Rodriguez-Noriega

2010-05-01

Full Text Available Pandemic influenza A (H1N1 virus emerged during 2009. To help clinicians triage adults with acute respiratory illness, a scoring system for influenza-like illness (ILI was implemented at Hospital Civil de Guadalajara, Mexico.A medical history, laboratory and radiology results were collected on emergency room (ER patients with acute respiratory illness to calculate an ILI-score. Patients were evaluated for admission by their ILI-score and clinicians' assessment of risk for developing complications. Nasal and throat swabs were collected from intermediate and high-risk patients for influenza testing by RT-PCR. The disposition and ILI-score of those oseltamivir-treated versus untreated, clinical characteristics of 2009 pandemic influenza A (H1N1 patients versus test-negative patients were compared by Pearson's Chi(2, Fisher's Exact, and Wilcoxon rank-sum tests.Of 1840 ER patients, 230 were initially hospitalized (mean ILI-score = 15, and the rest were discharged, including 286 ambulatory patients given oseltamivir (median ILI-score = 11, and 1324 untreated (median ILI-score = 5. Fourteen (1% untreated patients returned, and 3 were hospitalized on oseltamivir (median ILI-score = 19. Of 371 patients tested by RT-PCR, 104 (28% had pandemic influenza and 42 (11% had seasonal influenza A detected. Twenty (91% of 22 imaged hospitalized pandemic influenza patients had bilateral infiltrates compared to 23 (38% of 61 imaged hospital test-negative patients (p<0.001. One patient with confirmed pandemic influenza presented 6 days after symptom onset, required mechanical ventilation, and died.The triaging system that used an ILI-score complimented clinicians' judgment of who needed oseltamivir and inpatient care and helped hospital staff manage a surge in demand for services.

Benzoylurea Chitin Synthesis Inhibitors.

Science.gov (United States)

Sun, Ranfeng; Liu, Chunjuan; Zhang, Hao; Wang, Qingmin

2015-08-12

Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure-activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs.

SAH derived potent and selective EZH2 inhibitors

Energy Technology Data Exchange (ETDEWEB)

Kung, Pei-Pei; Huang, Buwen; Zehnder, Luke; Tatlock, John; Bingham, Patrick; Krivacic, Cody; Gajiwala, Ketan; Diehl, Wade; Yu, Xiu; Maegley, Karen A.

2015-04-01

A series of novel enhancer of zeste homolog 2 (EZH2) inhibitors was designed based on the chemical structure of the histone methyltransferase (HMT) inhibitor SAH (S-adenosyl-l-homocysteine). These nucleoside-based EZH2 inhibitors blocked the methylation of nucleosomes at H3K27 in biochemical assays employing both WT PRC2 complex as well as a Y641N mutant PRC2 complex. The most potent compound, 27, displayed IC50’s against both complexes of 270 nM and 70 nM, respectively. To our knowledge, compound 27 is the most potent SAH-derived inhibitor of the EZH2 PRC2 complex yet identified. This compound also displayed improved potency, lipophilic efficiency (LipE), and selectivity profile against other lysine methyltransferases compared with SAH.

A cyclic peptidic serine protease inhibitor

DEFF Research Database (Denmark)

Zhao, Baoyu; Xu, Peng; Jiang, Longguang

2014-01-01

Peptides are attracting increasing interest as protease inhibitors. Here, we demonstrate a new inhibitory mechanism and a new type of exosite interactions for a phage-displayed peptide library-derived competitive inhibitor, mupain-1 (CPAYSRYLDC), of the serine protease murine urokinase...... pocket, its carbonyl group aligning improperly relative to Ser195 and the oxyanion hole, explaining why the peptide is an inhibitor rather than a substrate. Substitution of the P1 Arg with novel unnatural Arg analogues with aliphatic or aromatic ring structures led to an increased affinity, depending......, in spite of a less favorable binding entropy and loss of a polar interaction. We conclude that increased flexibility of the peptide allows more favorable exosite interactions, which, in combination with the use of novel Arg analogues as P1 residues, can be used to manipulate the affinity and specificity...

Inhibitors of Fatty Acid Synthase for Prostate Cancer. Revision

Science.gov (United States)

2013-05-01

acetyl- cholinesterase inhibitors have been developed, many with femtomolar binding affinities (7). This body of literature also confirms that the...AD_________________ Award Number: W81XWH-09-1-0204 TITLE: Inhibitors of Fatty Acid Synthase for...May 2013 2. REPORT TYPE Revised Final 3. DATES COVERED 01 May 2009-30 Apr 2013 4. TITLE AND SUBTITLE Inhibitors of Fatty Acid Synthase for

The 'retro-design' concept for novel kinase inhibitors.

Science.gov (United States)

Müller, Gerhard; Sennhenn, Peter C; Woodcock, Timothy; Neumann, Lars

2010-07-01

Protein kinases are among the most attractive therapeutic targets for a broad range of diseases. This feature review highlights and classifies the main design principles employed to generate active and selective kinase inhibitors. In particular, emphasis is focused on a fragment-based lead-generation approach, which constitutes a novel design method for developing type II kinase inhibitors with distinct binding kinetic attributes. This 'retro-design' strategy relies on a customized fragment library, and contrasts the traditional approach used in the design of type II inhibitors.

New synthetic thrombin inhibitors: molecular design and experimental verification.

Directory of Open Access Journals (Sweden)

Elena I Sinauridze

Full Text Available BACKGROUND: The development of new anticoagulants is an important goal for the improvement of thromboses treatments. OBJECTIVES: The design, synthesis and experimental testing of new safe and effective small molecule direct thrombin inhibitors for intravenous administration. METHODS: Computer-aided molecular design of new thrombin inhibitors was performed using our original docking program SOL, which is based on the genetic algorithm of global energy minimization in the framework of a Merck Molecular Force Field. This program takes into account the effects of solvent. The designed molecules with the best scoring functions (calculated binding energies were synthesized and their thrombin inhibitory activity evaluated experimentally in vitro using a chromogenic substrate in a buffer system and using a thrombin generation test in isolated plasma and in vivo using the newly developed model of hemodilution-induced hypercoagulation in rats. The acute toxicities of the most promising new thrombin inhibitors were evaluated in mice, and their stabilities in aqueous solutions were measured. RESULTS: New compounds that are both effective direct thrombin inhibitors (the best K(I was 1111.1 mg/kg. A plasma-substituting solution supplemented with one of the new inhibitors prevented hypercoagulation in the rat model of hemodilution-induced hypercoagulation. Activities of the best new inhibitors in physiological saline (1 µM solutions were stable after sterilization by autoclaving, and the inhibitors remained stable at long-term storage over more than 1.5 years at room temperature and at 4°C. CONCLUSIONS: The high efficacy, stability and low acute toxicity reveal that the inhibitors that were developed may be promising for potential medical applications.

Aggregation of trypsin and trypsin inhibitor by Al cation.

Science.gov (United States)

Chanphai, P; Kreplak, L; Tajmir-Riahi, H A

2017-04-01

Al cation may trigger protein structural changes such as aggregation and fibrillation, causing neurodegenerative diseases. We report the effect of Al cation on the solution structures of trypsin (try) and trypsin inhibitor (tryi), using thermodynamic analysis, UV-Visible, Fourier transform infrared (FTIR) spectroscopic methods and atomic force microscopy (AFM). Thermodynamic parameters showed Al-protein bindings occur via H-bonding and van der Waals contacts for trypsin and trypsin inhibitor. AFM showed that Al cations are able to force trypsin into larger or more robust aggregates than trypsin inhibitor, with trypsin 5±1 SE (n=52) proteins per aggregate and for trypsin inhibitor 8.3±0.7 SE (n=118). Thioflavin T test showed no major protein fibrillation in the presence of Al cation. Al complexation induced more alterations of trypsin inhibitor conformation than trypsin. Copyright © 2017 Elsevier B.V. All rights reserved.

Peptide inhibitors of botulinum neurotoxin by mRNA display

International Nuclear Information System (INIS)

Yiadom, Kwabena P.A.B.; Muhie, Seid; Yang, David C.H.

2005-01-01

Botulinum neurotoxins (BoNTs) are extremely toxic. The metalloproteases associated with the toxins cleave proteins essential for neurotransmitter secretion. Inhibitors of the metalloprotease are currently sought to control the toxicity of BoNTs. Toward that goal, we produced a synthetic cDNA for the expression and purification of the metalloprotease of BoNT/A in Escherichia coli as a biotin-ubiquitin fusion protein, and constructed a combinatorial peptide library to screen for BoNT/A light chain inhibitors using mRNA display. A protease assay was developed using immobilized intact SNAP-25 as the substrate. The new peptide inhibitors showed a 10-fold increase in affinity to BoNT/A light chain than the parent peptide. Interestingly, the sequences of the new peptide inhibitors showed abundant hydrophobic residues but few hydrophilic residues. The results suggest that mRNA display may provide a general approach in developing peptide inhibitors of BoNTs

Cyclooxygenase-2 inhibitors and free flap complications after autologous breast reconstruction

DEFF Research Database (Denmark)

Bonde, Christian; Khorasani, Hoda; Hoejvig, Jens

2017-01-01

BACKGROUND: A key component of modern analgesics is the use of multimodal opioid-sparing analgesia (MOSA). In the past, our analgesic regime after autologous breast reconstruction (ABR) included either NSAID or a selective cyclooxygenase-2 (COX-2) inhibitor. COX-2 inhibitors are superior to NSAID...... or gastrointestinal bleeding. CONCLUSIONS: Multimodal analgesia using a COX-2 inhibitor is safe in ABR with free flaps and does not increase flap failure. COX-2 inhibitors seem superior to NSAID with reduced risk of post-operative haematomas.......BACKGROUND: A key component of modern analgesics is the use of multimodal opioid-sparing analgesia (MOSA). In the past, our analgesic regime after autologous breast reconstruction (ABR) included either NSAID or a selective cyclooxygenase-2 (COX-2) inhibitor. COX-2 inhibitors are superior to NSAIDs...... because of the well-known side effects of NSAID treatment (bleeding/gastrointestinal ulcers). However, COX-2 inhibitors have been suggested to increase flap failure rates. We report our experience in using COX-2 inhibitors as part of our post-operative MOSA after ABR using free flaps. MATERIALS...

Review. Elimination of viruses in plants: twenty years of progress

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A. Panattoni

2013-02-01

Full Text Available To shed light on trends about elimination of viruses from plants, a bibliographic research was conducted to identify thermotherapy, chemotherapy and tissue culture trials published from 1991 through 2010. Among woody plants, grapevine, apple and peach are the most frequent targets of sanitation protocols because their health status is strictly regulated. Even if thermotherapy represents the preferred method for the host, grapevine viruses can also be eliminated with chemotherapy and tissue culture; apple viruses respond to chemotherapy as well. Although a similar trend was reported among herbaceous plants, chemotherapy was the most frequently used technique in potato. With regard to virus, thermotherapy was successfully applied against viruses belonging to 13 families and an unassigned genus. Instead, chemotherapy and tissue culture techniques eradicated viruses belonging to fewer families (nine. An interpretation of thermotherapy effects considers the new metabolic “pathways” triggered by the natural antiviral response emitted by the infected plant, with particular reference to virus-induced gene silencing. With regard to chemotherapy, several groups of antiviral drugs belong to inosine monophosphate dehydrogenase inhibitors, S-adenosylhomocysteine hydrolase inhibitors, neuraminidase inhibitors. Tissue culture, usually adopted to regenerate plantlets in biotechnological breeding programs, represents the less used tool for eliminate viruses from plants.

Kinase inhibitors: a new class of antirheumatic drugs

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Kyttaris VC

2012-09-01

Full Text Available Vasileios C KyttarisDivision of Rheumatology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USAAbstract: The outlook for patients with rheumatoid arthritis has improved significantly over the last three decades with the use of disease-modifying antirheumatic drugs. However, despite the use of methotrexate, cytokine inhibitors, and molecules targeting T and B cells, a percentage of patients do not respond or lose their response over time. The autoimmune process in rheumatoid arthritis depends on activation of immune cells, which utilize intracellular kinases to respond to external stimuli such as cytokines, immune complexes, and antigens. In the past decade, small molecules targeting several kinases, such as p38 MAPK, Syk, and JAK have been developed. Several p38 MAPK inhibitors proved ineffective in treating rheumatoid arthritis. The Syk inhibitor, fostamatinib, proved superior to placebo in Phase II trials and is currently under Phase III investigation. Tofacitinib, a JAK1/3 inhibitor, was shown to be efficacious in two Phase III trials, while VX-509, a JAK3 inhibitor, showed promising results in a Phase II trial. Fostamatinib and tofacitinib were associated with increased rates of infection, elevation of liver enzymes, and neutropenia. Moreover, fostamatinib caused elevations of blood pressure and diarrhea, while tofacitinib was associated with an increase in creatinine and elevation of lipid levels.Keywords: rheumatoid arthritis, kinase inhibitors, mitogen-activated phosphokinase p38, spleen tyrosine kinase, Janus kinases

Chemoproteomics-Aided Medicinal Chemistry for the Discovery of EPHA2 Inhibitors.

Science.gov (United States)

Heinzlmeir, Stephanie; Lohse, Jonas; Treiber, Tobias; Kudlinzki, Denis; Linhard, Verena; Gande, Santosh Lakshmi; Sreeramulu, Sridhar; Saxena, Krishna; Liu, Xiaofeng; Wilhelm, Mathias; Schwalbe, Harald; Kuster, Bernhard; Médard, Guillaume

2017-06-21

The receptor tyrosine kinase EPHA2 has gained attention as a therapeutic drug target for cancer and infectious diseases. However, EPHA2 research and EPHA2-based therapies have been hampered by the lack of selective small-molecule inhibitors. Herein we report the synthesis and evaluation of dedicated EPHA2 inhibitors based on the clinical BCR-ABL/SRC inhibitor dasatinib as a lead structure. We designed hybrid structures of dasatinib and the previously known EPHA2 binders CHEMBL249097, PD-173955, and a known EPHB4 inhibitor in order to exploit both the ATP pocket entrance as well as the ribose pocket as binding epitopes in the kinase EPHA2. Medicinal chemistry and inhibitor design were guided by a chemical proteomics approach, allowing early selectivity profiling of the newly synthesized inhibitor candidates. Concomitant protein crystallography of 17 inhibitor co-crystals delivered detailed insight into the atomic interactions that underlie the structure-affinity relationship. Finally, the anti-proliferative effect of the inhibitor candidates was confirmed in the glioblastoma cell line SF-268. In this work, we thus discovered a novel EPHA2 inhibitor candidate that features an improved selectivity profile while maintaining potency against EPHA2 and anticancer activity in SF-268 cells. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Different angiotensin-converting enzyme inhibitors have similar clinical efficacy after myocardial infarction

DEFF Research Database (Denmark)

Hansen, Morten L; Gislason, Gunnar H; Køber, Lars

2008-01-01

What is already known about this subject: Treatment with an angiotensin-converting enzyme (ACE) inhibitor benefits many patients with cardiovascular disease. ACE inhibitors are generally assumed to be equally effective, but this has never been fully verified in clinical trials. What this study adds...... important and not which ACE inhibitor is used. AIM: Therapy with angiotensin-converting enzyme (ACE) inhibitors is common after myocardial infarction (MI). Given the lack of randomized trials comparing different ACE inhibitors, the association among ACE inhibitors after MI in risk for mortality...

Discovery and SAR of hydantoin TACE inhibitors

Energy Technology Data Exchange (ETDEWEB)

Yu, Wensheng; Guo, Zhuyan; Orth, Peter; Madison, Vincent; Chen, Lei; Dai, Chaoyang; Feltz, Robert J.; Girijavallabhan, Vinay M.; Kim, Seong Heon; Kozlowski, Joseph A.; Lavey, Brian J.; Li, Dansu; Lundell, Daniel; Niu, Xiaoda; Piwinski, John J.; Popovici-Muller, Janeta; Rizvi, Razia; Rosner, Kristin E.; Shankar, Bandarpalle B.; Shih, Neng-Yang; Siddiqui, M.A.; Sun, J.; Tong, L.; Umland, S.; Wong, M.K.; Yang, D.Y.; Zhou, G. (Merck)

2010-09-03

We disclose inhibitors of TNF-{alpha} converting enzyme (TACE) designed around a hydantoin zinc binding moiety. Crystal structures of inhibitors bound to TACE revealed monodentate coordination of the hydantoin to the zinc. SAR, X-ray, and modeling designs are described. To our knowledge, these are the first reported X-ray structures of TACE with a hydantoin zinc ligand.

Bicyclic peptide inhibitor of urokinase-type plasminogen activator

DEFF Research Database (Denmark)

Roodbeen, Renée; Jensen, Berit Paaske; Jiang, Longguang

2013-01-01

The development of protease inhibitors for pharmacological intervention has taken a new turn with the use of peptide-based inhibitors. Here, we report the rational design of bicyclic peptide inhibitors of the serine protease urokinase-type plasminogen activator (uPA), based on the established...... investigated the solution structures of the bicyclic peptide by NMR spectroscopy to map possible conformations. An X-ray structure of the bicyclic-peptide-uPA complex confirmed an interaction similar to that for the previous upain-1/upain-2-uPA complexes. These physical studies of the peptide...

A novel method for screening the glutathione transferase inhibitors

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Węgrzyn Grzegorz

2009-03-01

Full Text Available Abstract Background Glutathione transferases (GSTs belong to the family of Phase II detoxification enzymes. GSTs catalyze the conjugation of glutathione to different endogenous and exogenous electrophilic compounds. Over-expression of GSTs was demonstrated in a number of different human cancer cells. It has been found that the resistance to many anticancer chemotherapeutics is directly correlated with the over-expression of GSTs. Therefore, it appears to be important to find new GST inhibitors to prevent the resistance of cells to anticancer drugs. In order to search for glutathione transferase (GST inhibitors, a novel method was designed. Results Our results showed that two fragments of GST, named F1 peptide (GYWKIKGLV and F2 peptide (KWRNKKFELGLEFPNL, can significantly inhibit the GST activity. When these two fragments were compared with several known potent GST inhibitors, the order of inhibition efficiency (measured in reactions with 2,4-dinitrochlorobenzene (CDNB and glutathione as substrates was determined as follows: tannic acid > cibacron blue > F2 peptide > hematin > F1 peptide > ethacrynic acid. Moreover, the F1 peptide appeared to be a noncompetitive inhibitor of the GST-catalyzed reaction, while the F2 peptide was determined as a competitive inhibitor of this reaction. Conclusion It appears that the F2 peptide can be used as a new potent specific GST inhibitor. It is proposed that the novel method, described in this report, might be useful for screening the inhibitors of not only GST but also other enzymes.

Environmental life cycle analysis of potato sprout inhibitors

NARCIS (Netherlands)

Kerstholt, R.P.V.; Ree, C.M.; Moll, H.C.

Potato sprout inhibitors are generally applied to suppress sprouting during winter storage. This study presents the compared environmental profiles of the two sprout inhibitors available on the Dutch market: A traditional chemical product with isopropyl-3-chlorophenylcarbamate (CIPC) and

Hepatitis C Virus NS3 Inhibitors: Current and Future Perspectives

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Kazi Abdus Salam

2013-01-01

Full Text Available Currently, hepatitis C virus (HCV infection is considered a serious health-care problem all over the world. A good number of direct-acting antivirals (DAAs against HCV infection are in clinical progress including NS3-4A protease inhibitors, RNA-dependent RNA polymerase inhibitors, and NS5A inhibitors as well as host targeted inhibitors. Two NS3-4A protease inhibitors (telaprevir and boceprevir have been recently approved for the treatment of hepatitis C in combination with standard of care (pegylated interferon plus ribavirin. The new therapy has significantly improved sustained virologic response (SVR; however, the adverse effects associated with this therapy are still the main concern. In addition to the emergence of viral resistance, other targets must be continually developed. One such underdeveloped target is the helicase portion of the HCV NS3 protein. This review article summarizes our current understanding of HCV treatment, particularly with those of NS3 inhibitors.

Monoamine Oxidase Inhibitors (MAOIs)

Science.gov (United States)

... health-medications/index.shtml. Accessed May 16, 2016. Hirsch M, et al. Monoamine oxidase inhibitors (MAOIs) for ... www.uptodate.com/home. Accessed May 16, 2016. Hirsch M, et al. Discontinuing antidepressant medications in adults. ...

Recent Natural Corrosion Inhibitors for Mild Steel: An Overview

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Marko Chigondo

2016-01-01

Full Text Available Traditionally, reduction of corrosion has been managed by various methods including cathodic protection, process control, reduction of the metal impurity content, and application of surface treatment techniques, as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent monetary losses due to metallic corrosion on industrial vessels, equipment, or surfaces. Inorganic and organic inhibitors are toxic and costly and thus recent focus has been turned to develop environmentally benign methods for corrosion retardation. Many researchers have recently focused on corrosion prevention methods using green inhibitors for mild steel in acidic solutions to mimic industrial processes. This paper provides an overview of types of corrosion, corrosion process, and mainly recent work done on the application of natural plant extracts as corrosion inhibitors for mild steel.

[Isomeric derivatives of lupinine and epilupinine--organophosphorus inhibitors of cholinesterases].

Science.gov (United States)

Basova, N E; Kormilitsyn, B N; Perchenok, A Iu; Rosengart, E V; Saakov, V S; Suvorov, A A

2012-01-01

The isomeric-structure analysis data of anticholinesterase action of organophosphorous inhibitors with similar structure help in the search of specific effectors and detection of differences in reactivity of various animals' enzymes. This study compared the data of efficacy in respect of 4 mammal and 5 arthropoda cholinesterase preparations for 26 quinolizidine inhibitors, which molecules contain both the isomeric unbranched and branched alkoxyl radicals in the phosphoryl group, and the epimeric lupinine and epilupinine derivatives in the leaving group. The changes in the alkoxyl radical structure of inhibitor molecules act on their efficacy only with respect to the mammal enzymes ("group" inhibitor specificity). The differences between lupinine and epilupinine derivatives were revealed. Highly specific inhibitors of different enzymes were detected among the tested compounds.

Lansoprazole and carbonic anhydrase IX inhibitors sinergize against human melanoma cells.

Science.gov (United States)

Federici, Cristina; Lugini, Luana; Marino, Maria Lucia; Carta, Fabrizio; Iessi, Elisabetta; Azzarito, Tommaso; Supuran, Claudiu T; Fais, Stefano

2016-01-01

Proton Pump Inhibitors (PPIs) reduce tumor acidity and therefore resistance of tumors to drugs. Carbonic Anhydrase IX (CA IX) inhibitors have proven to be effective against tumors, while tumor acidity might impair their full effectiveness. To analyze the effect of PPI/CA IX inhibitors combined treatment against human melanoma cells. The combination of Lansoprazole (LAN) and CA IX inhibitors (FC9-399A and S4) has been investigated in terms of cell proliferation inhibition and cell death in human melanoma cells. The combination of these inhibitors was more effective than the single treatments in both inhibiting cell proliferation and in inducing cell death in human melanoma cells. These results represent the first successful attempt in combining two different proton exchanger inhibitors. This is the first evidence on the effectiveness of a new approach against tumors based on the combination of PPI and CA IX inhibitors, thus providing an alternative strategy against tumors.

Escape from Human Immunodeficiency Virus Type 1 (HIV-1 Entry Inhibitors

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Carol D. Weiss

2012-12-01

Full Text Available The human immunodeficiency virus (HIV enters cells through a series of molecular interactions between the HIV envelope protein and cellular receptors, thus providing many opportunities to block infection. Entry inhibitors are currently being used in the clinic, and many more are under development. Unfortunately, as is the case for other classes of antiretroviral drugs that target later steps in the viral life cycle, HIV can become resistant to entry inhibitors. In contrast to inhibitors that block viral enzymes in intracellular compartments, entry inhibitors interfere with the function of the highly variable envelope glycoprotein as it continuously adapts to changing immune pressure and available target cells in the extracellular environment. Consequently, pathways and mechanisms of resistance for entry inhibitors are varied and often involve mutations across the envelope gene. This review provides a broad overview of entry inhibitor resistance mechanisms that inform our understanding of HIV entry and the design of new inhibitors and vaccines.

Cancer risk and use of protease inhibitor or nonnucleoside reverse transcriptase inhibitor-based combination antiretroviral therapy: the D: A: D study

NARCIS (Netherlands)

Bruyand, M.; Ryom, L.; Shepherd, L.; Fatkenheuer, G.; Grulich, A.; Reiss, P.; Wit, S. de; Monforte, A.M.; Furrer, H.; Pradier, C.; Lundgren, J.; Sabin, C.; Warris, A.; et al.,

2015-01-01

BACKGROUND: The association between combination antiretroviral therapy (cART) and cancer risk, especially regimens containing protease inhibitors (PIs) or nonnucleoside reverse transcriptase inhibitors (NNRTIs), is unclear. METHODS: Participants were followed from the latest of D:A:D study entry or

Cancer risk and use of protease inhibitor or nonnucleoside reverse transcriptase inhibitor-based combination antiretroviral therapy : the D: A: D study

NARCIS (Netherlands)

Bruyand, Mathias; Ryom, Lene; Shepherd, Leah; Fatkenheuer, Gerd; Grulich, Andrew; Reiss, Peter; de Wit, Stéphane; D Arminio Monforte, Antonella; Furrer, Hansjakob; Pradier, Christian; Lundgren, Jens; Sabin, Caroline; Schölvinck, Elisabeth H.

2015-01-01

BACKGROUND: The association between combination antiretroviral therapy (cART) and cancer risk, especially regimens containing protease inhibitors (PIs) or nonnucleoside reverse transcriptase inhibitors (NNRTIs), is unclear. METHODS: Participants were followed from the latest of D:A:D study entry or

Role of sialic acid in insulin action and the insulin resistance of diabetes mellitus

International Nuclear Information System (INIS)

Salhanick, A.I.; Amatruda, J.M.

1988-01-01

Adipocytes treated with neuraminidase show markedly reduced responsiveness to insulin without any alteration in insulin binding. In addition, several studies have separately demonstrated both insulin resistance and decreases in membrane sialic acid content and associated biosynthetic enzymes in diabetes mellitus. In the present study, the authors investigated the role that sialic acid residues may play in insulin action and in the hepatic insulin resistance associated with nonketotic diabetes. Primary cultures of hepatocytes from normal rats treated with neuraminidase demonstrated a dose-dependent decrease in insulin-stimulated lipogenesis. At a concentration of neuraminidase that decreases insulin action by 50%, 23% of total cellular sialic acid content was released. Neuraminidase-releasable sialic acid was significantly decreased in hepatocytes from diabetic rats and this was associated with significant insulin resistance. Treatment of hepatocytes from diabetic rats with cytidine 5'-monophospho-N-acetylneuraminic acid (CMP-NANA) enhanced insulin responsiveness 39%. The enhanced insulin responsiveness induced by CMP-NANA was blocked by cytidine 5'-monophosphate (CMP) suggesting that the CMP-NANA effect was catalyzed by a cell surface sialyl-transferase. CMP reduced neuraminidase-releasable [ 14 C]sialic acid incorporation into hepatocytes by 43%. The data demonstrate a role for cell surface sialic acid residues in hepatic insulin action and support a role for decreased cell surface sialic acid residues in the insulin resistance of diabetes mellitus

Overcoming imatinib resistance using Src inhibitor CGP76030, Abl inhibitor nilotinib and Abl/Lyn inhibitor INNO-406 in newly established K562 variants with BCR-ABL gene amplification.

Science.gov (United States)

Morinaga, Koji; Yamauchi, Takahiro; Kimura, Shinya; Maekawa, Taira; Ueda, Takanori

2008-06-01

Because imatinib (IM) resistance in chronic myeloid leukemia is primarily caused by the re-establishment of Abl kinase, new inhibitors may be efficacious. We evaluated 3 new agents against 2 new K562 variants, IM-R1 and IM-R2 cells, which were developed having 7- and 27-fold greater IM resistance, respectively, than the parental K562 cells. Both variants possessed BCR-ABL gene amplification along with elevated levels of its transcript and protein. Greater BCR-ABL gene amplification was observed in IM-R2 cells than in IM-R1 cells, which was consistent with the higher mRNA and protein levels of Bcr-Abl, and ultimately correlated with the greater IM resistance in IM-R2 cells. No mutation in the Abl kinase domain was detected in either variant. Despite the absence of Lyn overexpression, the Src kinase inhibitor CGP76030 showed positive cooperability with IM in inhibiting cell growth of not only K562 cells but also these 2 variants. This might be because of the augmented inhibition of Erk1/2 phosphorylation. The new Abl kinase inhibitor nilotinib was 10-fold more potent than IM in inhibiting the growth of K562 cells. Nilotinib inhibited the growth of IM-R1 and IM-R2 cells as potently as K562 cells. The combination of nilotinib with CGP76030 showed little additivity, because the potency of nilotinib masked the efficacy of CGP76030. The new dual Abl/Lyn inhibitor INNO-406 (formerly NS-187) was slightly more potent than nilotinib in inhibiting the growth of all 3 cell lines. Because BCR-ABL gene amplification occurs in blast crisis, these inhibitors might overcome IM resistance in such patients' leukemia. (c) 2008 Wiley-Liss, Inc.

Genetic characterization of circulating seasonal Influenza A viruses (2005-2009) revealed introduction of oseltamivir resistant H1N1 strains during 2009 in eastern India.

Science.gov (United States)

Agrawal, Anurodh S; Sarkar, Mehuli; Ghosh, Swati; Roy, Tapasi; Chakrabarti, Sekhar; Lal, Renu; Mishra, Akhilesh C; Chadha, Mandeep S; Chawla-Sarkar, Mamta

2010-12-01

Influenza surveillance was implemented in Kolkata, eastern India in 2005 to identify the circulating subtypes and characterize their genetic diversity. Throat and nasal swabs were collected from outpatients with influenza-like illness (ILI). Of 2844 ILI cases identified at two referral hospitals during October 2005-September 2009, 309 (10.86%) were positive for Influenza A by real time RT-PCR, of which 110 (35.60%) were subtyped as H1N1 and 199 (64.40%) as H3N2. Comparison of the nucleotide (nt) and amino acid (aa) sequences of the HA1 gene for H1N1 and H3N2 strains showed that a subset of strains precede WHO recommended contemporary strains by 1-2 years. The Kolkata H1N1 strains clustered in Clade II, subgroup 2B with A/Brisbane/59/2007 but were distant from the corresponding vaccine strains (New Caledonia/20/99 and A/Solomon Island/3/06). The 2005-06 and 2007 H3N2 strains (15/17) clustered either A/Brisbane/10/2007-like (n=8) or A/Nepal/921/2006 like (n=7) strains, whereas 2008 strains (8/12) and 2009 strains (4/4) were similar to the 2010-11 vaccine strain A/Perth/16/2009. More aa substitutions were found in HA or NA genes of H3N2 than in H1N1 strains. No mutation conferring neuraminidase resistance was observed in any of the strain during 2005-08, however in 2009, drug resistant marker (H275Y) was present in seasonal H1N1, but not in co-circulating H3N2 strains. This is the first report of genetic characterization of circulating Influenza A strains from India. The results also highlight the importance of continuing Influenza surveillance in developing countries of Asia for monitoring unusual strains with pandemic potential and mutations conferring antiviral resistance. Copyright © 2010 Elsevier B.V. All rights reserved.

A novel class of small molecule inhibitors of HDAC6.

Science.gov (United States)

Inks, Elizabeth S; Josey, Benjamin J; Jesinkey, Sean R; Chou, C James

2012-02-17

Histone deacetylases (HDACs) are a family of enzymes that play significant roles in numerous biological processes and diseases. HDACs are best known for their repressive influence on gene transcription through histone deacetylation. Mapping of nonhistone acetylated proteins and acetylation-modifying enzymes involved in various cellular pathways has shown protein acetylation/deacetylation also plays key roles in a variety of cellular processes including RNA splicing, nuclear transport, and cytoskeletal remodeling. Studies of HDACs have accelerated due to the availability of small molecule HDAC inhibitors, most of which contain a canonical hydroxamic acid or benzamide that chelates the metal catalytic site. To increase the pool of unique and novel HDAC inhibitor pharmacophores, a pharmacological active compound screen was performed. Several unique HDAC inhibitor pharmacophores were identified in vitro. One class of novel HDAC inhibitors, with a central naphthoquinone structure, displayed a selective inhibition profile against HDAC6. Here we present the results of a unique class of HDAC6 inhibitors identified using this compound library screen. In addition, we demonstrated that treatment of human acute myeloid leukemia cell line MV4-11 with the selective HDAC6 inhibitors decreases levels of mutant FLT-3 and constitutively active STAT5 and attenuates Erk phosphorylation, all of which are associated with the inhibitor's selective toxicity against leukemia.

Avian influenza viruses that cause highly virulent infections in humans exhibit distinct replicative properties in contrast to human H1N1 viruses

Science.gov (United States)

Simon, Philippe F.; de La Vega, Marc-Antoine; Paradis, Éric; Mendoza, Emelissa; Coombs, Kevin M.; Kobasa, Darwyn; Beauchemin, Catherine A. A.

2016-04-01

Avian influenza viruses present an emerging epidemiological concern as some strains of H5N1 avian influenza can cause severe infections in humans with lethality rates of up to 60%. These have been in circulation since 1997 and recently a novel H7N9-subtyped virus has been causing epizootics in China with lethality rates around 20%. To better understand the replication kinetics of these viruses, we combined several extensive viral kinetics experiments with mathematical modelling of in vitro infections in human A549 cells. We extracted fundamental replication parameters revealing that, while both the H5N1 and H7N9 viruses replicate faster and to higher titers than two low-pathogenicity H1N1 strains, they accomplish this via different mechanisms. While the H7N9 virions exhibit a faster rate of infection, the H5N1 virions are produced at a higher rate. Of the two H1N1 strains studied, the 2009 pandemic H1N1 strain exhibits the longest eclipse phase, possibly indicative of a less effective neuraminidase activity, but causes infection more rapidly than the seasonal strain. This explains, in part, the pandemic strain’s generally slower growth kinetics and permissiveness to accept mutations causing neuraminidase inhibitor resistance without significant loss in fitness. Our results highlight differential growth properties of H1N1, H5N1 and H7N9 influenza viruses.

Design, Synthesis and Biological Evaluation of Histone Deacetylase (HDAC) Inhibitors: Saha (Vorinostat) Analogs and Biaryl Indolyl Benzamide Inhibitors Display Isoform Selectivity

Science.gov (United States)

Negmeldin, Ahmed Thabet

HDAC proteins have emerged as interesting targets for anti-cancer drugs due to their involvement in cancers, as well as several other diseases. Several HDAC inhibitors have been approved by the FDA as anti-cancer drugs, including SAHA (suberoylanilide hydroxamic acid, Vorinostat). Unfortunately, SAHA inhibits most HDAC isoforms, which limit its use as a pharmacological tool and may lead to side effects in the clinic. In this work we were interested in developing isoform selective HDAC inhibitors, which may decrease or eliminate the side effects associated with non-selective inhibitors treatment. In addition, isoform selective HDAC inhibitors can be used as biological tools to help understand the HDAC-related cancer biology. Our strategy was based on synthesis and screening of several derivatives of the non-selective FDA approved drug SAHA substituted at different positions of the linker region. Several SAHA analogs modified at the C4 and C5 positions of the linker were synthesized. The new C4- and C5-modified SAHA libraries, along with the previously synthesized C2-modified SAHA analogs were screened in vitro and in cellulo for HDAC isoform selectivity. Interestingly, several analogs exhibited dual HDAC6/HDAC8 selectivity. Enantioselective syntheses of the pure enantiomers of some of the interesting analogs were performed and the enantiomers were screened in vitro. Among the most interesting analogs, ( R)-C4-benzyl SAHA displayed 520- to 1300-fold selectivity for HDAC6 and HDAC8 over HDAC1, 2, and 3, with IC50 values of 48 and 27 nM with HDAC6 and 8, respectively. Docking studies were performed to provide structural rationale for the observed selectivity of the new analogs. In addition, rational design, synthesis, and screening of several other biaryl indolyl benzamide HDAC inhibitors is discussed, and some showed modest HDAC1 selectivity. The new biaryl indolyl benzamides can be useful to further develop HDAC1 selective inhibitors. The dual HDAC6/8 selective

Impact of sodium–glucose cotransporter 2 inhibitors on blood pressure

Directory of Open Access Journals (Sweden)

Reed JW

2016-10-01

Full Text Available James W Reed Morehouse School of Medicine, Atlanta, GA, USA Abstract: SGLT2 inhibitors are glucose-lowering agents used to treat type 2 diabetes mellitus (T2DM. These agents target the kidney to promote urinary glucose excretion, resulting in improved blood glucose control. SGLT2-inhibitor therapy is also associated with weight loss and blood pressure (BP lowering. Hypertension is a common comorbidity in patients with T2DM, and is associated with excess morbidity and mortality. This review summarizes data on the effect of SGLT2 inhibitors marketed in the US (namely canagliflozin, dapagliflozin, or empagliflozin on BP in patients with T2DM. Boolean searches were conducted that included terms related to BP or hypertension with terms for SGLT2 inhibitors, canagliflozin, dapagliflozin, or empagliflozin using PubMed, Google, and Google Scholar. Data from numerous randomized controlled trials of SGLT2 inhibitors in patients with T2DM demonstrated clinically relevant reductions in both systolic and diastolic BP, assessed via seated office measurements and 24-hour ambulatory BP monitoring. Observed BP lowering was not associated with compensatory increases in heart rate. Circadian BP rhythm was also maintained. The mechanism of SGLT2 inhibitor-associated BP reduction is not fully understood, but is assumed to be related to osmotic diuresis and natriuresis. Other factors that may also contribute to BP reduction include SGLT2 inhibitor-associated decreases in body weight and reduced arterial stiffness. Local inhibition of the renin–angiotensin–aldosterone system secondary to increased delivery of sodium to the juxtaglomerular apparatus during SGLT2 inhibition has also been postulated. Although SGLT2 inhibitors are not indicated as BP-lowering agents, the modest decreases in systolic and diastolic BP observed with SGLT2 inhibitors may provide an extra clinical advantage for the majority of patients with T2DM, in addition to improving blood glucose

Organophosphate acetylcholine esterase inhibitor poisoning from a home-made shampoo.

Science.gov (United States)

Sadaka, Yair; Broides, Arnon; Tzion, Raffi Lev; Lifshitz, Matitiahu

2011-07-01

Organophosphate acetylcholine esterase inhibitor poisoning is a major health problem in children. We report an unusual cause of organophosphate acetylcholine esterase inhibitor poisoning. Two children were admitted to the pediatric intensive care unit due to organophosphate acetylcholine esterase inhibitor poisoning after exposure from a home-made shampoo that was used for the treatment of head lice. Owing to no obvious source of poisoning, the diagnosis of organophosphate acetylcholine esterase inhibitor poisoning in one of these patients was delayed. Both patients had an uneventful recovery. Organophosphate acetylcholine esterase inhibitor poisoning from home-made shampoo is possible. In cases where the mode of poisoning is unclear, direct questioning about the use of home-made shampoo is warranted, in these cases the skin and particularly the scalp should be rinsed thoroughly as soon as possible.

The Nonglycemic Actions of Dipeptidyl Peptidase-4 Inhibitors

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Na-Hyung Kim

2014-01-01

Full Text Available A cell surface serine protease, dipeptidyl peptidase 4 (DPP-4, cleaves dipeptide from peptides containing proline or alanine in the N-terminal penultimate position. Two important incretin hormones, glucagon-like peptide-1 (GLP-1 and glucose-dependent insulinotropic peptide (GIP, enhance meal-stimulated insulin secretion from pancreatic β-cells, but are inactivated by DPP-4. Diabetes and hyperglycemia increase the DPP-4 protein level and enzymatic activity in blood and tissues. In addition, multiple other functions of DPP-4 suggest that DPP-4 inhibitor, a new class of antidiabetic agents, may have pleiotropic effects. Studies have shown that DPP-4 itself is involved in the inflammatory signaling pathway, the stimulation of vascular smooth cell proliferation, and the stimulation of oxidative stress in various cells. DPP-4 inhibitor ameliorates these pathophysiologic processes and has been shown to have cardiovascular protective effects in both in vitro and in vivo experiments. However, in recent randomized clinical trials, DPP-4 inhibitor therapy in high risk patients with type 2 diabetes did not show cardiovascular protective effects. Some concerns on the actions of DPP-4 inhibitor include sympathetic activation and neuropeptide Y-mediated vascular responses. Further studies are required to fully characterize the cardiovascular effects of DPP-4 inhibitor.

A novel small molecule inhibitor of hepatitis C virus entry.

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Carl J Baldick

Full Text Available Small molecule inhibitors of hepatitis C virus (HCV are being developed to complement or replace treatments with pegylated interferons and ribavirin, which have poor response rates and significant side effects. Resistance to these inhibitors emerges rapidly in the clinic, suggesting that successful therapy will involve combination therapy with multiple inhibitors of different targets. The entry process of HCV into hepatocytes represents another series of potential targets for therapeutic intervention, involving viral structural proteins that have not been extensively explored due to experimental limitations. To discover HCV entry inhibitors, we utilized HCV pseudoparticles (HCVpp incorporating E1-E2 envelope proteins from a genotype 1b clinical isolate. Screening of a small molecule library identified a potent HCV-specific triazine inhibitor, EI-1. A series of HCVpp with E1-E2 sequences from various HCV isolates was used to show activity against all genotype 1a and 1b HCVpp tested, with median EC50 values of 0.134 and 0.027 µM, respectively. Time-of-addition experiments demonstrated a block in HCVpp entry, downstream of initial attachment to the cell surface, and prior to or concomitant with bafilomycin inhibition of endosomal acidification. EI-1 was equally active against cell-culture adapted HCV (HCVcc, blocking both cell-free entry and cell-to-cell transmission of virus. HCVcc with high-level resistance to EI-1 was selected by sequential passage in the presence of inhibitor, and resistance was shown to be conferred by changes to residue 719 in the carboxy-terminal transmembrane anchor region of E2, implicating this envelope protein in EI-1 susceptibility. Combinations of EI-1 with interferon, or inhibitors of NS3 or NS5A, resulted in additive to synergistic activity. These results suggest that inhibitors of HCV entry could be added to replication inhibitors and interferons already in development.

Impact of sodium–glucose cotransporter 2 inhibitors on blood pressure

Science.gov (United States)

Reed, James W

2016-01-01

SGLT2 inhibitors are glucose-lowering agents used to treat type 2 diabetes mellitus (T2DM). These agents target the kidney to promote urinary glucose excretion, resulting in improved blood glucose control. SGLT2-inhibitor therapy is also associated with weight loss and blood pressure (BP) lowering. Hypertension is a common comorbidity in patients with T2DM, and is associated with excess morbidity and mortality. This review summarizes data on the effect of SGLT2 inhibitors marketed in the US (namely canagliflozin, dapagliflozin, or empagliflozin) on BP in patients with T2DM. Boolean searches were conducted that included terms related to BP or hypertension with terms for SGLT2 inhibitors, canagliflozin, dapagliflozin, or empagliflozin using PubMed, Google, and Google Scholar. Data from numerous randomized controlled trials of SGLT2 inhibitors in patients with T2DM demonstrated clinically relevant reductions in both systolic and diastolic BP, assessed via seated office measurements and 24-hour ambulatory BP monitoring. Observed BP lowering was not associated with compensatory increases in heart rate. Circadian BP rhythm was also maintained. The mechanism of SGLT2 inhibitor-associated BP reduction is not fully understood, but is assumed to be related to osmotic diuresis and natriuresis. Other factors that may also contribute to BP reduction include SGLT2 inhibitor-associated decreases in body weight and reduced arterial stiffness. Local inhibition of the renin–angiotensin–aldosterone system secondary to increased delivery of sodium to the juxtaglomerular apparatus during SGLT2 inhibition has also been postulated. Although SGLT2 inhibitors are not indicated as BP-lowering agents, the modest decreases in systolic and diastolic BP observed with SGLT2 inhibitors may provide an extra clinical advantage for the majority of patients with T2DM, in addition to improving blood glucose control. PMID:27822054

Sodium-Glucose Linked Transporter-2 Inhibitors in Chronic Kidney Disease

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L. Zanoli

2015-01-01

Full Text Available SGLT2 inhibitors are new antihyperglycaemic agents whose ability to lower glucose is directly proportional to GFR. Therefore, in chronic kidney disease (CKD the blood glucose lowering effect is reduced. Unlike many current therapies, the mechanism of action of SGLT2 inhibitors is independent of insulin action or beta-cell function. In addition, the mechanism of action of SGLT2 inhibitors is complementary and not alternative to other antidiabetic agents. SGLT2 inhibitors could be potentially effective in attenuating renal hyperfiltration and, consequently, the progression of CKD. Moreover, the reductions in intraglomerular pressure, systemic blood pressure, and uric acid levels induced by SGLT inhibition may potentially be of benefit in CKD subjects without diabetes. However, at present, only few clinical studies were designed to evaluate the effects of SGLT2 inhibitors in CKD. Consequently, safety and potential efficacy beyond blood glucose lowering should be better clarified in CKD. In this paper we provide an updated review of the use of SGLT2 inhibitors in clinical practice, with particular attention on subjects with CKD.

Cost of care of haemophilia with inhibitors.

Science.gov (United States)

Di Minno, M N D; Di Minno, G; Di Capua, M; Cerbone, A M; Coppola, A

2010-01-01

In Western countries, the treatment of patients with inhibitors is presently the most challenging and serious issue in haemophilia management, direct costs of clotting factor concentrates accounting for >98% of the highest economic burden absorbed for the healthcare of patients in this setting. Being designed to address questions of resource allocation and effectiveness, decision models are the golden standard to reliably assess the overall economic implications of haemophilia with inhibitors in terms of mortality, bleeding-related morbidity, and severity of arthropathy. However, presently, most data analyses stem from retrospective short-term evaluations, that only allow for the analysis of direct health costs. In the setting of chronic diseases, the cost-utility analysis, that takes into account the beneficial effects of a given treatment/healthcare intervention in terms of health-related quality of life, is likely to be the most appropriate approach. To calculate net benefits, the quality adjusted life year, that significantly reflects such health gain, has to be compared with specific economic impacts. Differences in data sources, in medical practice and/or in healthcare systems and costs, imply that most current pharmacoeconomic analyses are confined to a narrow healthcare payer perspective. Long-term/lifetime prospective or observational studies, devoted to a careful definition of when to start a treatment; of regimens (dose and type of product) to employ, and of inhibitor population (children/adults, low-responding/high responding inhibitors) to study, are thus urgently needed to allow for newer insights, based on reliable data sources into resource allocation, effectiveness and cost-utility analysis in the treatment of haemophiliacs with inhibitors.

5 alpha-reductase inhibitors and prostatic disease.

Science.gov (United States)

Schröder, F H

1994-08-01

5 alpha-Reductase inhibitors are a new class of substances with very specific effects on type I and type II 5 alpha R which may be of use in the treatment of skin disease, such as male pattern baldness, male acne and hirsutism, as well as prostatic hyperplasia and prostate cancer. At least two types of 5 alpha R inhibitors with a different pH optimum have been described. cDNA encoding for both the type I and the type II enzyme has been cloned. Most of the orally effective 5 alpha R inhibitors belong to the class of 4-azasteroids. The radical substituted in the 17 position of the steroid ring seems to be related to species specific variations and to the types of 5 alpha R enzymes in different species and organ systems. 5 alpha R inhibitors lead to a decrease of plasma DHT by about 65% while there is a slight rise in plasma testosterone. The decrease of tissue DHT in the ventral prostate of the intact rat, the dog and in humans is more pronounced and amounts to about 85%. There is a reciprocal rise of tissue T in these systems. The application of an inhibitor of 5 alpha R type II leads to a shrinkage of BPH in men by about 30%. In the rat a similar shrinkage accompanied by a significant decrease of total organ DNA occurs. This decrease, however, is not as pronounced as can be achieved with castration.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular characterization of partial fusion gene and C-terminus extension length of haemagglutinin-neuraminidase gene of recently isolated Newcastle disease virus isolates in Malaysia

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Berhanu Ayalew

2010-08-01

Full Text Available Abstract Background Newcastle disease (ND, caused by Newcastle disease virus (NDV, is a highly contagious disease of birds and has been one of the major causes of economic losses in the poultry industry. Despite routine vaccination programs, sporadic cases have occasionally occurred in the country and remain a constant threat to commercial poultry. Hence, the present study was aimed to characterize NDV isolates obtained from clinical cases in various locations of Malaysia between 2004 and 2007 based on sequence and phylogenetic analysis of partial F gene and C-terminus extension length of HN gene. Results The coding region of eleven NDV isolates fusion (F gene and carboxyl terminal region of haemagglutinin-neuraminidase (HN gene including extensions were amplified by reverse transcriptase PCR and directly sequenced. All the isolates have shown to have non-synonymous to synonymous base substitution rate ranging between 0.081 - 0.264 demonstrating presence of negative selection. Analysis based on F gene showed the characterized isolates possess three different types of protease cleavage site motifs; namely 112RRQKRF117, 112RRRKRF117 and 112GRQGRL117 and appear to show maximum identities with isolates in the region such as cockatoo/14698/90 (Indonesia, Ch/2000 (China, local isolate AF2240 indicating the high similarity of isolates circulating in the South East Asian countries. Meanwhile, one of the isolates resembles commonly used lentogenic vaccine strains. On further characterization of the HN gene, Malaysian isolates had C-terminus extensions of 0, 6 and 11 amino acids. Analysis of the phylogenetic tree revealed that the existence of three genetic groups; namely, genotype II, VII and VIII. Conclusions The study concluded that the occurrence of three types of NDV genotypes and presence of varied carboxyl terminus extension lengths among Malaysian isolates incriminated for sporadic cases.

Molecular characterization of partial fusion gene and C-terminus extension length of haemagglutinin-neuraminidase gene of recently isolated Newcastle disease virus isolates in Malaysia.

Science.gov (United States)

Berhanu, Ayalew; Ideris, Aini; Omar, Abdul R; Bejo, Mohd Hair

2010-08-08

Newcastle disease (ND), caused by Newcastle disease virus (NDV), is a highly contagious disease of birds and has been one of the major causes of economic losses in the poultry industry. Despite routine vaccination programs, sporadic cases have occasionally occurred in the country and remain a constant threat to commercial poultry. Hence, the present study was aimed to characterize NDV isolates obtained from clinical cases in various locations of Malaysia between 2004 and 2007 based on sequence and phylogenetic analysis of partial F gene and C-terminus extension length of HN gene. The coding region of eleven NDV isolates fusion (F) gene and carboxyl terminal region of haemagglutinin-neuraminidase (HN) gene including extensions were amplified by reverse transcriptase PCR and directly sequenced. All the isolates have shown to have non-synonymous to synonymous base substitution rate ranging between 0.081 - 0.264 demonstrating presence of negative selection. Analysis based on F gene showed the characterized isolates possess three different types of protease cleavage site motifs; namely 112RRQKRF117, 112RRRKRF117 and 112GRQGRL117 and appear to show maximum identities with isolates in the region such as cockatoo/14698/90 (Indonesia), Ch/2000 (China), local isolate AF2240 indicating the high similarity of isolates circulating in the South East Asian countries. Meanwhile, one of the isolates resembles commonly used lentogenic vaccine strains. On further characterization of the HN gene, Malaysian isolates had C-terminus extensions of 0, 6 and 11 amino acids. Analysis of the phylogenetic tree revealed that the existence of three genetic groups; namely, genotype II, VII and VIII. The study concluded that the occurrence of three types of NDV genotypes and presence of varied carboxyl terminus extension lengths among Malaysian isolates incriminated for sporadic cases.

Real-Time Inhibitor Recession Measurements in the Space Shuttle Reusable Solid Rocket Motors

Science.gov (United States)

McWhorter, Bruce B.; Ewing, Mark E.; McCool, Alex (Technical Monitor)

2001-01-01

Real-time char line recession measurements were made on propellant inhibitors of the Space Shuttle Reusable Solid Rocket Motor (RSRM). The RSRM FSM-8 static test motor propellant inhibitors (composed of a rubber insulation material) were successfully instrumented with eroding potentiometers and thermocouples. The data was used to establish inhibitor recession versus time relationships. Normally, pre-fire and post-fire insulation thickness measurements establish the thermal performance of an ablating insulation material. However, post-fire inhibitor decomposition and recession measurements are complicated by the fact that most of the inhibitor is back during motor operation. It is therefore a difficult task to evaluate the thermal protection offered by the inhibitor material. Real-time measurements would help this task. The instrumentation program for this static test motor marks the first time that real-time inhibitors. This report presents that data for the center and aft field joint forward facing inhibitors. The data was primarily used to measure char line recession of the forward face of the inhibitors which provides inhibitor thickness reduction versus time data. The data was also used to estimate the inhibitor height versus time relationship during motor operation.

Crystal structure of a novel cysteinless plant Kunitz-type protease inhibitor

International Nuclear Information System (INIS)

Hansen, Daiane; Macedo-Ribeiro, Sandra; Verissimo, Paula; Yoo Im, Sonia; Sampaio, Misako Uemura; Oliva, Maria Luiza Vilela

2007-01-01

Bauhinia bauhinioides Cruzipain Inhibitor (BbCI) is a cysteine protease inhibitor highly homologous to plant Kunitz-type inhibitors. However, in contrast to classical Kunitz family inhibitors it lacks cysteine residues and therefore disulfide bridges. BbCI is also distinct in the ability to inactivate enzymes belonging to two different classes, cysteine and serine proteases. Besides inhibiting the cysteine protease cruzipain, BbCI also inhibits cathepsin L and the serine proteases HNE (human neutrophil elastase) and PPE (porcine pancreatic elastase). Monoclinic crystals of the recombinant inhibitor that diffract to 1.7 A resolution were obtained using hanging drop method by vapor diffusion at 18 o C. The refined structure shows the conservative β-trefoil fold features of the Kunitz inhibitors. In BbCI, one of the two characteristic S-S bonds is replaced by the water-mediated interaction between Tyr125 and Gly132. In this work we explore the structural differences between Kunitz-type inhibitors and analyze the essential interactions that maintain the protein structural stability preserving its biological function

HDAC inhibitors: modulating leukocyte differentiation, survival, proliferation and inflammation.

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Sweet, Matthew J; Shakespear, Melanie R; Kamal, Nabilah A; Fairlie, David P

2012-01-01

Therapeutic effects of histone deacetylase (HDAC) inhibitors in cancer models were first linked to their ability to cause growth arrest and apoptosis of tumor cells. It is now clear that these agents also have pleiotropic effects on angiogenesis and the immune system, and some of these properties are likely to contribute to their anti-cancer activities. It is also emerging that inhibitors of specific HDACs affect the differentiation, survival and/or proliferation of distinct immune cell populations. This is true for innate immune cells such as macrophages, as well as cells of the acquired immune system, for example, T-regulatory cells. These effects may contribute to therapeutic profiles in some autoimmune and chronic inflammatory disease models. Here, we review our current understanding of how classical HDACs (HDACs 1-11) and their inhibitors impact on differentiation, survival and proliferation of distinct leukocyte populations, as well as the likely relevance of these effects to autoimmune and inflammatory disease processes. The ability of HDAC inhibitors to modulate leukocyte survival may have implications for the rationale of developing selective inhibitors as anti-inflammatory drugs.

High throughput in vivo protease inhibitor selection platform

DEFF Research Database (Denmark)

2017-01-01

The invention relates to a recombinant microbial cell comprising a selection platform for screening for a protease inhibitor, wherein the platform comprises transgenes encoding a protease having selective peptide bond cleavage activity at a recognition site amino acid sequence; and transgenes...... platform for screening for a protease inhibitor....

Polyaspartic acid as a green corrosion inhibitor for carbon steel

Energy Technology Data Exchange (ETDEWEB)

Cui, R. [Department of Chemistry, Hebei Normal University, Shijiazhuang 050016 (China); Department of Chemistry and Materials Engineering, Changshu Institute of Technology, Changshu 215500 (China); Gu, N.; Li, C. [Department of Chemistry, Hebei Normal University, Shijiazhuang 050016 (China)

2011-04-15

The inhibitor effect of the environmentally friendly corrosion inhibitor polyaspartic acid (PASP) on the corrosion of carbon steel in 0.5 M H{sub 2}SO{sub 4} was investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). Polarization curve results clearly reveal the fact that PASP is a good anode-type inhibitor. EIS results confirm its corrosion inhibition ability. The inhibition efficiency increases with increasing PASP concentration, and the maximum inhibition efficiency was 80.33% at 10 C. SEM reveals that a protective film forms on the surface of the inhibited sample. The adsorption of this inhibitor is found to follow the Freundlich adsorption isotherm. A mechanism is proposed to explain the inhibitory action of the corrosion inhibitor. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Charged amino acid variability related to N-glyco -sylation and epitopes in A/H3N2 influenza: Hem -agglutinin and neuraminidase.

Directory of Open Access Journals (Sweden)

Zhong-Zhou Huang

Full Text Available The A/H3N2 influenza viruses circulated in humans have been shown to undergo antigenic drift, a process in which amino acid mutations result from nucleotide substitutions. There are few reports regarding the charged amino acid mutations. The purpose of this paper is to explore the relations between charged amino acids, N-glycosylation and epitopes in hemagglutinin (HA and neuraminidase (NA.A total of 700 HA genes (691 NA genes of A/H3N2 viruses were chronologically analyzed for the mutational variants in amino acid features, N-glycosylation sites and epitopes since its emergence in 1968.It was found that both the number of HA N-glycosylation sites and the electric charge of HA increased gradually up to 2016. The charges of HA and HA1 increased respectively 1.54-fold (+7.0 /+17.8 and 1.08-fold (+8.0/+16.6 and the number of NGS in nearly doubled (7/12. As great diversities occurred in 1990s, involving Epitope A, B and D mutations, the charged amino acids in Epitopes A, B, C and D in HA1 mutated at a high frequency in global circulating strains last decade. The charged amino acid mutations in Epitopes A (T135K has shown high mutability in strains near years, resulting in a decrease of NGT135-135. Both K158N and K160T not only involved mutations charged in epitope B, but also caused a gain of NYT158-160. Epitope B and its adjacent N-glycosylation site NYT158-160 mutated more frequently, which might be under greater immune pressure than the rest.The charged amino acid mutations in A/H3N2 Influenza play a significant role in virus evolution, which might cause an important public health issue. Variability related to both the epitopes (A and B and N-glycosylation is beneficial for understanding the evolutionary mechanisms, disease pathogenesis and vaccine research.

Transglutaminase inhibitor from milk

NARCIS (Netherlands)

Jong, G.A.H. de; Wijngaards, G.; Koppelman, S.J.

2003-01-01

Cross-linking experiments of skimmed bovine milk with bacterial transglutaminase isolated from Streptoverticillium mobaraense showed only some degree of formation of high-molecular-weight casein polymers. Studies on the nature of this phenomenon revealed that bovine milk contains an inhibitor of

Prospective surveillance and molecular characterization of seasonal influenza in a university cohort in Singapore.

Science.gov (United States)

Virk, Ramandeep Kaur; Tambyah, Paul Anantharajah; Inoue, Masafumi; Lim, Elizabeth Ai-Sim; Chan, Ka-Wei; Chua, Catherine; Tan, Boon-Huan

2014-01-01

Southeast Asia is believed to be a potential locus for the emergence of novel influenza strains, and therefore accurate sentinel surveillance in the region is critical. Limited information exists on sentinel surveillance of influenza-like illness (ILI) in young adults in Singapore in a University campus setting. The objective of the present study was to determine the proportion of ILI caused by influenza A and B viruses in a university cohort in Singapore. We conducted a prospective surveillance study from May through October 2007, at the National University of Singapore (NUS). Basic demographic information and nasopharyngeal swabs were collected from students and staff with ILI. Reverse-transcriptase PCR (RT-PCR) and viral isolation were employed to detect influenza viruses. Sequencing of hemagglutinin (HA) and neuraminidase (NA) genes of some representative isolates was also performed. Overall proportions of influenza A and B virus infections were 47/266 (18%) and 9/266 (3%) respectively. The predominant subtype was A/H3N2 (55%) and the rest were A/H1N1 (45%). The overall sensitivity difference for detection of influenza A viruses using RT-PCR and viral isolation was 53%. Phylogenetic analyses of HA and NA gene sequences of Singapore strains showed identities higher than 98% within both the genes. The strains were more similar to strains included in the WHO vaccine recommendation for the following year (2008). Genetic markers of oseltamivir resistance were not detected in any of the sequenced Singapore isolates. HA and NA gene sequences of Singapore strains were similar to vaccine strains for the upcoming influenza season. No drug resistance was found. Sentinel surveillance on university campuses should make use of molecular methods to better detect emerging and re-emerging influenza viral threats.

Prospective surveillance and molecular characterization of seasonal influenza in a university cohort in Singapore.

Directory of Open Access Journals (Sweden)

Ramandeep Kaur Virk

Full Text Available BACKGROUND: Southeast Asia is believed to be a potential locus for the emergence of novel influenza strains, and therefore accurate sentinel surveillance in the region is critical. Limited information exists on sentinel surveillance of influenza-like illness (ILI in young adults in Singapore in a University campus setting. The objective of the present study was to determine the proportion of ILI caused by influenza A and B viruses in a university cohort in Singapore. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a prospective surveillance study from May through October 2007, at the National University of Singapore (NUS. Basic demographic information and nasopharyngeal swabs were collected from students and staff with ILI. Reverse-transcriptase PCR (RT-PCR and viral isolation were employed to detect influenza viruses. Sequencing of hemagglutinin (HA and neuraminidase (NA genes of some representative isolates was also performed. Overall proportions of influenza A and B virus infections were 47/266 (18% and 9/266 (3% respectively. The predominant subtype was A/H3N2 (55% and the rest were A/H1N1 (45%. The overall sensitivity difference for detection of influenza A viruses using RT-PCR and viral isolation was 53%. Phylogenetic analyses of HA and NA gene sequences of Singapore strains showed identities higher than 98% within both the genes. The strains were more similar to strains included in the WHO vaccine recommendation for the following year (2008. Genetic markers of oseltamivir resistance were not detected in any of the sequenced Singapore isolates. CONCLUSIONS/SIGNIFICANCE: HA and NA gene sequences of Singapore strains were similar to vaccine strains for the upcoming influenza season. No drug resistance was found. Sentinel surveillance on university campuses should make use of molecular methods to better detect emerging and re-emerging influenza viral threats.

Natural compounds as corrosion inhibitors for highly cycled systems

Energy Technology Data Exchange (ETDEWEB)

Quraishi, M.A.; Farooqi, I.H.; Saini, P.A. [Corrosion Research Lab., Aligarh (India)

1999-11-01

Strict environmental legislations have led to the development of green inhibitors in recent years. In continuation of the authors` research work on development of green inhibitors, they have investigated the aqueous extracts of three plants namely: Azadirachta indica, Punica Granatum and Momordica charantia as corrosion inhibitors for mild steel in 3% NaCl using weight loss and electrochemical methods. All the investigated compounds exhibited excellent corrosion inhibition properties comparable to that of HEDP. Azadirachta showed better scale inhibition effect than HEDP.

New halogenated phenylcoumarins as tyrosinase inhibitors.

Science.gov (United States)

Matos, Maria João; Santana, Lourdes; Uriarte, Eugenio; Delogu, Giovanna; Corda, Marcella; Fadda, Maria Benedetta; Era, Benedetta; Fais, Antonella

2011-06-01

With the aim to find out structural features for the tyrosinase inhibitory activity, in the present communication we report the synthesis and pharmacological evaluation of a new series of phenylcoumarin derivatives with different number of hydroxyl or ether groups and bromo substituent in the scaffold. The synthesized compounds 5-12 were evaluated as mushroom tyrosinase inhibitors showing, two of them, lower IC(50) than the umbelliferone. Compound 12 (IC(50)=215 μM) is the best tyrosinase inhibitor of this series. Copyright © 2011 Elsevier Ltd. All rights reserved.

Phytochemicals as Green Corrosion Inhibitors in Various Corrosive ...

African Journals Online (AJOL)

There is an intensive effort underway to develop new plant origin corrosion inhibitors for metal subjected to various environmental conditions. These efforts have been motivated by the desire to replace toxic inhibitors used for mitigation of corrosion of various metals and alloys in aqueous solutions. Plants represent a class ...

Effect of Wall Shear Stress on Corrosion Inhibitor Film Performance

Science.gov (United States)

Canto Maya, Christian M.

In oil and gas production, internal corrosion of pipelines causes the highest incidence of recurring failures. Ensuring the integrity of ageing pipeline infrastructure is an increasingly important requirement. One of the most widely applied methods to reduce internal corrosion rates is the continuous injection of chemicals in very small quantities, called corrosion inhibitors. These chemical substances form thin films at the pipeline internal surface that reduce the magnitude of the cathodic and/or anodic reactions. However, the efficacy of such corrosion inhibitor films can be reduced by different factors such as multiphase flow, due to enhanced shear stress and mass transfer effects, loss of inhibitor due to adsorption on other interfaces such as solid particles, bubbles and droplets entrained by the bulk phase, and due to chemical interaction with other incompatible substances present in the stream. The first part of the present project investigated the electrochemical behavior of two organic corrosion inhibitors (a TOFA/DETA imidazolinium, and an alkylbenzyl dimethyl ammonium chloride), with and without an inorganic salt (sodium thiosulfate), and the resulting enhancement. The second part of the work explored the performance of corrosion inhibitor under multiphase (gas/liquid, solid/liquid) flow. The effect of gas/liquid multiphase flow was investigated using small and large scale apparatus. The small scale tests were conducted using a glass cell and a submersed jet impingement attachment with three different hydrodynamic patterns (water jet, CO 2 bubbles impact, and water vapor cavitation). The large scale experiments were conducted applying different flow loops (hilly terrain and standing slug systems). Measurements of weight loss, linear polarization resistance (LPR), and adsorption mass (using an electrochemical quartz crystal microbalance, EQCM) were used to quantify the effect of wall shear stress on the performance and integrity of corrosion inhibitor

Novel targeted therapeutics: inhibitors of MDM2, ALK and PARP

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Hsueh Chung-Tsen

2011-04-01

Full Text Available Abstract We reviewed preclinical data and clinical development of MDM2 (murine double minute 2, ALK (anaplastic lymphoma kinase and PARP (poly [ADP-ribose] polymerase inhibitors. MDM2 binds to p53, and promotes degradation of p53 through ubiquitin-proteasome degradation. JNJ-26854165 and RO5045337 are 2 small-molecule inhibitors of MDM2 in clinical development. ALK is a transmembrane protein and a member of the insulin receptor tyrosine kinases. EML4-ALK fusion gene is identified in approximately 3-13% of non-small cell lung cancer (NSCLC. Early-phase clinical studies with Crizotinib, an ALK inhibitor, in NSCLC harboring EML4-ALK have demonstrated promising activity with high response rate and prolonged progression-free survival. PARPs are a family of nuclear enzymes that regulates the repair of DNA single-strand breaks through the base excision repair pathway. Randomized phase II study has shown adding PARP-1 inhibitor BSI-201 to cytotoxic chemotherapy improves clinical outcome in patients with triple-negative breast cancer. Olaparib, another oral small-molecule PARP inhibitor, demonstrated encouraging single-agent activity in patients with advanced breast or ovarian cancer. There are 5 other PARP inhibitors currently under active clinical investigation.

Screening of inhibitors for remediation of asphaltene deposits: Experimental and modeling study

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Mehdi Madhi

2018-06-01

Full Text Available One of the most severe problems during production from heavy crude oil reservoirs is the formation of asphaltene precipitation and as a result deposition in the tubing, surface facilities and near wellbore region which causes oil production and permeability reduction in addition to rock wettability alteration in the reservoir. So one of the economical ways to prevent such incidents is using the chemicals which are called asphaltene inhibitor.In this study, the influence of three commercial inhibitors, namely; Cetyl Terimethyl Ammonium Bromide (CTAB, Sodium Dodecyl Sulfate (SDS, Triton X-100 and four non-commercial (Benzene, Benzoic Acid, Salicylic Acid, Naphthalene inhibitors on two Iranian crude oils were investigated. This study extends previous works and contributes toward the better understanding of interactions between asphaltene and inhibitor. Effect of functional groups and structure of inhibitors on asphaltene precipitation were studied and it seems clear that the nature and polarity of asphaltene (structure and amount of impurities presented has a significant impact on the selection of inhibitors. asphaltene dispersant tests and Core flood tests were designed for evaluation of inhibitors in static and dynamic conditions. The results revealed distinguished mechanisms for asphaltene solubilization/dispersion (such as hydrogen bonding, π–π interaction and acid-base interaction and influence of additional side group (OH on inhibition power of inhibitor.During the experiments, it was found that increasing inhibitor concentration may lead to the self-assembly of inhibitor and declining of asphaltene stabilization. So, finding optimum concentration of inhibitor with high efficiency and available at a reasonable price is very important. The results suggest that 600 ppm of CTAB and 300 ppm of SDS were approximately optimum concentrations for the studied crude oils. One of the most important findings that differ from previous studies is the

Pulmonary Toxicity of Cholinesterase Inhibitors

National Research Council Canada - National Science Library

Hilmas, Corey; Adler, Michael; Baskin, Steven I; Gupta, Ramesh C

2006-01-01

.... Whereas nerve agents were produced primarily for military deployment, other cholinesterase inhibitors were used for treating conditions such as myasthenia gravis and as pretreaunents for nerve agent exposure...

Assessment of zoonotic potential of four European swine influenza viruses in the ferret model

DEFF Research Database (Denmark)

Fobian, Kristina; P. Fabrizio, Thomas; Yoon, Sun-Woo

herds and enhanced focus on risk assessment of these new viruses. In this study, four European swine influenza viruses were assessed for their zoonotic potential. Of the four viruses, two were enzootic viruses of subtype H1N2 (with avian-like H1) and H3N2 and two were new reassortants, one with avian......The reverse zoonotic events that introduced the 2009 pandemic influenza virus into swine herds have drastically increased the diversity of reassortants throughout Europe. The pandemic potential of these novel reassortments is unknown, hence necessitating enhanced surveillance of European swine...... to neuraminidase inhibitors. These findings suggest that the investigated viruses have the potential to infect humans and further underline the need for continued surveillance as well as pandemic and zoonotic assessment of new influenza reassortants....

Costs and utilization of hemophilia A and B patients with and without inhibitors.

Science.gov (United States)

Armstrong, Edward P; Malone, Daniel C; Krishnan, Sangeeta; Wessler, Maj Jacob

2014-11-01

To evaluate the health system costs among patients with hemophilia A and B with and without inhibitors over 5 years. This was a retrospective, observational study utilizing medical and pharmacy electronic medical records and administrative encounters/claims data tracking US patients between 2006-2011. Patients with diagnosis codes for hemophilia A and B were identified. Patients with inhibitors were characterized by utilization of bypassing agents activated prothrombin complex concentrate or factor VIIa on two or more distinct dates. Severity was classified as mild, moderate, or severe based on laboratory tests of clotting factor. There were 160 hemophilia A patients and 54 hemophilia B patients identified. From this group, seven were designated as patients with inhibitors (five with hemophilia A and two with hemophilia B). Hemophilia A patients without inhibitors reported 65 (41.9%) as being severe, 19 (12.3%) as moderate, and 71 (45.8%) as mild. Hemophilia B patients without inhibitors reported nine (17.3%) had severe, 13 (25.0%) had moderate, and 30 (57.7%) had mild hemophilia. All patients with inhibitors had been hospitalized in the previous 5 years compared to 64 (41.3%) with hemophilia A without inhibitors and 22 (42.3%) with hemophilia B without inhibitors. The median aggregate cost per year (including factor and health resource use) was $325,780 for patients with inhibitors compared to $98,334 for hemophilia A patients without inhibitors and $23,265 for hemophilia B patients without inhibitors. The results suggest that, while the frequency of inhibitors within the hemophilia cohort was low, there was a higher frequency of hospitalizations, and the associated median aggregate costs per year were 3-fold higher than those patients without inhibitors. In contrast, hemophilia B patients experience less severe disease and account for lower aggregate yearly costs compared to either patients with hemophilia A or patients with inhibitors.

Cysteine peptidases and their inhibitors in breast and genital cancer.

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Magdalena Milan

2010-11-01

Full Text Available Cysteine proteinases and their inhibitors probably play the main role in carcinogenesis and metastasis. The metastasis process need external proteolytic activities that pass several barriers which are membranous structures of the connective tissue which includes, the basement membrane of blood vessels. Activities of the proteinases are regulated by endogenous inhibitors and activators. The imbalance between cysteine proteinases and cystatins seems to be associated with an increase in metastatic potential in some tumors. It has also been reported that proteinase inhibitors, specific antibodies for these enzymes and inhibition of the urokinase receptor may prevent cancer cell invasion. Some proteinase inhibitor could serve as agents for cancer treatment.

Structure based design of 11β-HSD1 inhibitors.

Science.gov (United States)

Singh, Suresh; Tice, Colin

2010-11-01

Controlling elevated tissue-specific levels of cortisol may provide a novel therapeutic approach for treating metabolic syndrome. This concept has spurred large scale medicinal chemistry efforts in the pharmaceutical industry for the design of 11β-HSD1 inhibitors. High resolution X-ray crystal structures of inhibitors in complex with the enzyme have facilitated the structure-based design of diverse classes of molecules. A summary of binding modes, trends in structure-activity relationships, and the pharmacodynamic data of inhibitors from each class is presented.

Inhibitors of MAO-A and MAO-B in Psychiatry and Neurology

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John Paul Maurice Finberg

2016-10-01

Full Text Available Inhibitors of MAO-A and MAO-B are in clinical use for the treatment of psychiatric and neurological disorders respectively. Elucidation of the molecular structure of the active sites of the enzymes has enabled a precise determination of the way in which substrates and inhibitor molecules are metabolized, or inhibit metabolism of substrates, respectively. Despite the knowledge of the strong antidepressant efficacy of irreversible MAO inhibitors, their clinical use has been limited by their side effect of potentiation of the cardiovascular effects of dietary amines (cheese effect. A number of reversible MAO-A inhibitors which are devoid of cheese effect have been described in the literature, but only one, moclobemide, is currently in clinical use. The irreversible inhibitors of MAO-B, selegiline and rasagiline, are used clinically in treatment of Parkinson’s disease, and a recently introduced reversible MAO-B inhibitor, safinamide, has also been found efficacious. Modification of the pharmacokinetic characteristics of selegiline by transdermal administration has led to the development of a new drug form for treatment of depression. The clinical potential of MAO inhibitors together with detailed knowledge of the enzyme’s binding site structure should lead to future developments with these drugs.

Inhibitors of MAO-A and MAO-B in Psychiatry and Neurology.

Science.gov (United States)

Finberg, John P M; Rabey, Jose M

2016-01-01

Inhibitors of MAO-A and MAO-B are in clinical use for the treatment of psychiatric and neurological disorders respectively. Elucidation of the molecular structure of the active sites of the enzymes has enabled a precise determination of the way in which substrates and inhibitor molecules are metabolized, or inhibit metabolism of substrates, respectively. Despite the knowledge of the strong antidepressant efficacy of irreversible MAO inhibitors, their clinical use has been limited by their side effect of potentiation of the cardiovascular effects of dietary amines ("cheese effect"). A number of reversible MAO-A inhibitors which are devoid of cheese effect have been described in the literature, but only one, moclobemide, is currently in clinical use. The irreversible inhibitors of MAO-B, selegiline and rasagiline, are used clinically in treatment of Parkinson's disease, and a recently introduced reversible MAO-B inhibitor, safinamide, has also been found efficacious. Modification of the pharmacokinetic characteristics of selegiline by transdermal administration has led to the development of a new drug form for treatment of depression. The clinical potential of MAO inhibitors together with detailed knowledge of the enzyme's binding site structure should lead to future developments with these drugs.

SEARCH OF NEW SYNTHETIC INHIBITORS OF TYROSINASE

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Yu. Shesterenko

2017-11-01

Full Text Available Melanin pigmentation of skin plays the most important role in the protection of organism against UV-irradiation, but the excessive accumulation of melanin brings to toxic melanodermia, melasma, lentigo and other skin lesions. Tyrosinase is the key enzyme of skin melanin pigment biosynthesis. In spite of certain progress in investigation of natural and synthetic tyrosinase inhibitors, actuality of such studies is of a high level, because the existing inhibitors are in some cases unstable, expensive, toxic, requires complex methods of synthesis or isolation from natural sources. The aim of the work is screening of new tyrosinase inhibitors, using the enzyme, isolated from Agaricus bisporus. Tyrosinase was isolated from Agaricus bisporus mushrooms by a modified method. It was found, that the introduction of polyethylene glycol 4000 in the extraction process promotes 3-fold reduction of polyphenol content, which leads to increase purity of enzyme with an increase in its activity by 25%. A search for new tyrosinase inhibitors among a wide range of compounds, including derivatives of 3-chloro-1,4-naphthoquinone, isatin, 3-hydroxy-2-naphthoic acid, etc was conducted. The studied substances did not displayed inhibitory effect at concentration of 0,1-0,5 mmol/dm3.

Peptide aldehyde inhibitors of bacterial peptide deformylases.

Science.gov (United States)

Durand, D J; Gordon Green, B; O'Connell, J F; Grant, S K

1999-07-15

Bacterial peptide deformylases (PDF, EC 3.5.1.27) are metalloenzymes that cleave the N-formyl groups from N-blocked methionine polypeptides. Peptide aldehydes containing a methional or norleucinal inhibited recombinant peptide deformylase from gram-negative Escherichia coli and gram-positive Bacillus subtilis. The most potent inhibitor was calpeptin, N-CBZ-Leu-norleucinal, which was a competitive inhibitor of the zinc-containing metalloenzymes, E. coli and B. subtilis PDF with Ki values of 26.0 and 55.6 microM, respectively. Cobalt-substituted E. coli and B. subtilis deformylases were also inhibited by these aldehydes with Ki values for calpeptin of 9.5 and 12.4 microM, respectively. Distinct spectral changes were observed upon binding of calpeptin to the Co(II)-deformylases, consistent with the noncovalent binding of the inhibitor rather than the formation of a covalent complex. In contrast, the chelator 1,10-phenanthroline caused the time-dependent inhibition of B. subtilis Co(II)-PDF activity with the loss of the active site metal. The fact that calpeptin was nearly equipotent against deformylases from both gram-negative and gram-positive bacterial sources lends further support to the idea that a single deformylase inhibitor might have broad-spectrum antibacterial activity. Copyright 1999 Academic Press.

Immune checkpoint inhibitors for metastatic bladder cancer.

Science.gov (United States)

Massari, Francesco; Di Nunno, Vincenzo; Cubelli, Marta; Santoni, Matteo; Fiorentino, Michelangelo; Montironi, Rodolfo; Cheng, Liang; Lopez-Beltran, Anto; Battelli, Nicola; Ardizzoni, Andrea

2018-03-01

Chemotherapy has represented the standard therapy for unresectable or metastatic urothelial carcinoma for more than 20 years. The growing knowledge of the interaction between tumour and immune system has led to the advent of new classes of drugs, the immune-checkpoints inhibitors, which are intended to change the current scenario. To date, immunotherapy is able to improve the overall responses and survival. Moreover, thanks to its safety profile immune-checkpoint inhibitors could be proposed also to patients unfit for standard chemotherapy. No doubts that these agents have started a revolution expected for years, but despite this encouraging results it appears clear that not all subjects respond to these agents and requiring the development of reliable predictive response factors able to isolate patients who can more benefit from these treatments as well as new strategies aimed to improve immunotherapy clinical outcome. In this review we describe the active or ongoing clinical trials involving Programmed Death Ligand 1 (PD-L1), Programmed Death receptor 1 (PD-1) and Cytotoxic-T Lymphocyte Antigen 4 (CTLA 4) inhibitors in urothelial carcinoma focusing our attention on the developing new immune-agents and combination strategies with immune-checkpoint inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

MAPK inhibitors, particularly the JNK inhibitor, increase cell death effects in H2O2-treated lung cancer cells via increased superoxide anion and glutathione depletion.

Science.gov (United States)

Park, Woo Hyun

2018-02-01

Reactive oxygen species (ROS), especially hydrogen peroxide (H2O2), induce apoptosis in cancer cells by regulating mitogen-activated protein kinase (MAPK) signaling pathways. The present study investigated the effects of MAPK inhibitors on cell growth and death as well as changes in ROS and glutathione (GSH) levels in H2O2-treated Calu-6 and A549 lung cancer cells. H2O2 inhibited growth and induced death of Calu-6 and A549 lung cancer cells. All MAPK inhibitors appeared to enhance growth inhibition in H2O2-treated Calu-6 and A549 lung cancer cells and increased the percentage of Annexin V-FITC-positive cells in these cancer cells. Among the MAPK inhibitors, a JNK inhibitor significantly augmented the loss of mitochondrial membrane potential (MMP; ΔΨm) in H2O2-treated Calu-6 and A549 lung cancer cells. Intracellular ROS levels were significantly increased in the H2O2-treated cells at 1 and 24 h. Only the JNK inhibitor increased ROS levels in the H2O2-treated cells at 1 h and all MAPK inhibitors raised superoxide anion levels in these cells at 24 h. In addition, H2O2 induced GSH depletion in Calu-6 and A549 cells and the JNK inhibitor significantly enhanced GSH depletion in H2O2‑treated cells. Each of the MAPK inhibitors altered ROS and GSH levels differently in the Calu-6 and A549 control cells. In conclusion, H2O2 induced growth inhibition and death in lung cancer cells through oxidative stress and depletion of GSH. The enhanced effect of MAPK inhibitors, especially the JNK inhibitor, on cell death in H2O2-treated lung cancer cells was correlated with increased O2•- levels and GSH depletion.

Cytogenetic study of Ascaris trypsin inhibitor in cultured human ...

Indian Academy of Sciences (India)

2009-04-01

Apr 1, 2009 ... Although the physical and chemical properties of Ascaris trypsin inhibitors ... male of Ascaris suum according to the method of Pudles and. Rola (1967). ..... inhibitor isolated from Ascaris resulted in the appearance of dominant ...

HDAC inhibitor L-carnitine and proteasome inhibitor bortezomib synergistically exert anti-tumor activity in vitro and in vivo.

Directory of Open Access Journals (Sweden)

Hongbiao Huang

Full Text Available Combinations of proteasome inhibitors and histone deacetylases (HDAC inhibitors appear to be the most potent to produce synergistic cytotoxicity in preclinical trials. We have recently confirmed that L-carnitine (LC is an endogenous HDAC inhibitor. In the current study, the anti-tumor effect of LC plus proteasome inhibitor bortezomib (velcade, Vel was investigated both in cultured hepatoma cancer cells and in Balb/c mice bearing HepG2 tumor. Cell death and cell viability were assayed by flow cytometry and MTS, respectively. Gene, mRNA expression and protein levels were detected by gene microarray, quantitative real-time PCR and Western blot, respectively. The effect of Vel on the acetylation of histone H3 associated with the p21(cip1 gene promoter was examined by using ChIP assay and proteasome peptidase activity was detected by cell-based chymotrypsin-like (CT-like activity assay. Here we report that (i the combination of LC and Vel synergistically induces cytotoxicity in vitro; (ii the combination also synergistically inhibits tumor growth in vivo; (iii two major pathways are involved in the synergistical effects of the combinational treatment: increased p21(cip1 expression and histone acetylation in vitro and in vivo and enhanced Vel-induced proteasome inhibition by LC. The synergistic effect of LC and Vel in cancer therapy should have great potential in the future clinical trials.

Cholinesterase inhibitors and hospitalization for bradycardia: a population-based study.

Directory of Open Access Journals (Sweden)

Laura Y Park-Wyllie

2009-09-01

Full Text Available BACKGROUND: Cholinesterase inhibitors are commonly used to treat dementia. These drugs enhance the effects of acetylcholine, and reports suggest they may precipitate bradycardia in some patients. We aimed to examine the association between use of cholinesterase inhibitors and hospitalization for bradycardia. METHODS AND FINDINGS: We examined the health care records of more than 1.4 million older adults using a case-time-control design, allowing each individual to serve as his or her own control. Case patients were residents of Ontario, Canada, aged 67 y or older hospitalized for bradycardia between January 1, 2003 and March 31, 2008. Control patients (3:1 were not hospitalized for bradycardia, and were matched to the corresponding case on age, sex, and a disease risk index. All patients had received cholinesterase inhibitor therapy in the 9 mo preceding the index hospitalization. We identified 1,009 community-dwelling older persons hospitalized for bradycardia within 9 mo of using a cholinesterase inhibitor. Of these, 161 cases informed the matched analysis of discordant pairs. Of these, 17 (11% required a pacemaker during hospitalization, and six (4% died prior to discharge. After adjusting for temporal changes in drug utilization, hospitalization for bradycardia was associated with recent initiation of a cholinesterase inhibitor (adjusted odds ratio [OR] 2.13, 95% confidence interval [CI] 1.29-3.51. The risk was similar among individuals with pre-existing cardiac disease (adjusted OR 2.25, 95% CI 1.18-4.28 and those receiving negative chronotropic drugs (adjusted OR 2.34, 95% CI 1.16-4.71. We found no such association when we replicated the analysis using proton pump inhibitors as a neutral exposure. Despite hospitalization for bradycardia, more than half of the patients (78 of 138 cases [57%] who survived to discharge subsequently resumed cholinesterase inhibitor therapy. CONCLUSIONS: Among older patients, initiation of cholinesterase

Comparative study of the hemagglutinin and neuraminidase genes of influenza A virus H3N2, H9N2, and H5N1 subtypes using bioinformatics techniques.

Science.gov (United States)

Ahn, Insung; Son, Hyeon S

2007-07-01

To investigate the genomic patterns of influenza A virus subtypes, such as H3N2, H9N2, and H5N1, we collected 1842 sequences of the hemagglutinin and neuraminidase genes from the NCBI database and parsed them into 7 categories: accession number, host species, sampling year, country, subtype, gene name, and sequence. The sequences that were isolated from the human, avian, and swine populations were extracted and stored in a MySQL database for intensive analysis. The GC content and relative synonymous codon usage (RSCU) values were calculated using JAVA codes. As a result, correspondence analysis of the RSCU values yielded the unique codon usage pattern (CUP) of each subtype and revealed no extreme differences among the human, avian, and swine isolates. H5N1 subtype viruses exhibited little variation in CUPs compared with other subtypes, suggesting that the H5N1 CUP has not yet undergone significant changes within each host species. Moreover, some observations may be relevant to CUP variation that has occurred over time among the H3N2 subtype viruses isolated from humans. All the sequences were divided into 3 groups over time, and each group seemed to have preferred synonymous codon patterns for each amino acid, especially for arginine, glycine, leucine, and valine. The bioinformatics technique we introduce in this study may be useful in predicting the evolutionary patterns of pandemic viruses.

The cardiovascular safety trials of DPP-4 inhibitors, GLP-1 agonists, and SGLT2 inhibitors.

Science.gov (United States)

Secrest, Matthew H; Udell, Jacob A; Filion, Kristian B

2017-04-01

In this paper, we review the results of large, double-blind, placebo-controlled randomized trials mandated by the US Food and Drug Administration to examine the cardiovascular safety of newly-approved antihyperglycemic agents in patients with type 2 diabetes. The cardiovascular effects of dipeptidyl peptidase-4 (DPP-4) inhibitors remain controversial: while these drugs did not reduce or increase the risk of primary, pre-specified composite cardiovascular outcomes, one DPP-4 inhibitor (saxagliptin) increased the risk of hospitalization for heart failure in the overall population; another (alogliptin) demonstrated inconsistent effects on heart failure hospitalization across subgroups of patients, and a third (sitagliptin) demonstrated no effect on heart failure. Evidence for cardiovascular benefits of glucagon-like peptide-1 (GLP-1) agonists has been similarly heterogeneous, with liraglutide and semaglutide reducing the risk of composite cardiovascular outcomes, but lixisenatide having no reduction or increase in cardiovascular risk. The effect of GLP-1 agonists on retinopathy remains a potential concern. In the only completed trial to date to assess a sodium-glucose cotransporter-2 (SGLT2) inhibitor, empagliflozin reduced the risk of composite cardiovascular endpoints, predominantly through its impact on cardiovascular mortality and heart failure hospitalization. Copyright © 2017 Elsevier Inc. All rights reserved.

Developing HIV-1 Protease Inhibitors through Stereospecific Reactions in Protein Crystals.

Science.gov (United States)

Olajuyigbe, Folasade M; Demitri, Nicola; De Zorzi, Rita; Geremia, Silvano

2016-10-31

Protease inhibitors are key components in the chemotherapy of HIV infection. However, the appearance of viral mutants routinely compromises their clinical efficacy, creating a constant need for new and more potent inhibitors. Recently, a new class of epoxide-based inhibitors of HIV-1 protease was investigated and the configuration of the epoxide carbons was demonstrated to play a crucial role in determining the binding affinity. Here we report the comparison between three crystal structures at near-atomic resolution of HIV-1 protease in complex with the epoxide-based inhibitor, revealing an in-situ epoxide ring opening triggered by a pH change in the mother solution of the crystal. Increased pH in the crystal allows a stereospecific nucleophile attack of an ammonia molecule onto an epoxide carbon, with formation of a new inhibitor containing amino-alcohol functions. The described experiments open a pathway for the development of new stereospecific protease inhibitors from a reactive lead compound.

Developing HIV-1 Protease Inhibitors through Stereospecific Reactions in Protein Crystals

Directory of Open Access Journals (Sweden)

Folasade M. Olajuyigbe

2016-10-01

Full Text Available Protease inhibitors are key components in the chemotherapy of HIV infection. However, the appearance of viral mutants routinely compromises their clinical efficacy, creating a constant need for new and more potent inhibitors. Recently, a new class of epoxide-based inhibitors of HIV-1 protease was investigated and the configuration of the epoxide carbons was demonstrated to play a crucial role in determining the binding affinity. Here we report the comparison between three crystal structures at near-atomic resolution of HIV-1 protease in complex with the epoxide-based inhibitor, revealing an in-situ epoxide ring opening triggered by a pH change in the mother solution of the crystal. Increased pH in the crystal allows a stereospecific nucleophile attack of an ammonia molecule onto an epoxide carbon, with formation of a new inhibitor containing amino-alcohol functions. The described experiments open a pathway for the development of new stereospecific protease inhibitors from a reactive lead compound.

A bioavailable cathepsin S nitrile inhibitor abrogates tumor development.

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Wilkinson, Richard D A; Young, Andrew; Burden, Roberta E; Williams, Rich; Scott, Christopher J

2016-04-21

Cathepsin S has been implicated in a variety of malignancies with genetic ablation studies demonstrating a key role in tumor invasion and neo-angiogenesis. Thus, the application of cathepsin S inhibitors may have clinical utility in the treatment of cancer. In this investigation, we applied a cell-permeable dipeptidyl nitrile inhibitor of cathepsin S, originally developed to target cathepsin S in inflammatory diseases, in both in vitro and in vivo tumor models. Validation of cathepsin S selectivity was carried out by assaying fluorogenic substrate turnover using recombinant cathepsin protease. Complete kinetic analysis was carried out and true K i values calculated. Abrogation of tumour invasion using murine MC38 and human MCF7 cell lines were carried out in vitro using a transwell migration assay. Effect on endothelial tube formation was evaluated using primary HUVEC cells. The effect of inhibitor in vivo on MC38 and MCF7 tumor progression was evaluated using cells propagated in C57BL/6 and BALB/c mice respectively. Subsequent immunohistochemical staining of proliferation (Ki67) and apoptosis (TUNEL) was carried out on MCF7 tumors. We confirmed that this inhibitor was able to selectively target cathepsin S over family members K, V, L and B. The inhibitor also significantly reduced MC38 and MCF7 cell invasion and furthermore, significantly reduced HUVEC endothelial tubule formation in vitro. In vivo analysis revealed that the compound could significantly reduce tumor volume in murine MC38 syngeneic and MCF7 xenograft models. Immunohistochemical analysis of MCF7 tumors revealed cathepsin S inhibitor treatment significantly reduced proliferation and increased apoptosis. In summary, these results highlight the characterisation of this nitrile cathepsin S inhibitor using in vitro and in vivo tumor models, presenting a compound which may be used to further dissect the role of cathepsin S in cancer progression and may hold therapeutic potential.

Oral direct thrombin inhibitors or oral factor Xa inhibitors for the treatment of deep vein thrombosis.

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Robertson, Lindsay; Kesteven, Patrick; McCaslin, James E

2015-06-30

Deep vein thrombosis (DVT) is a condition in which a clot forms in the deep veins, most commonly of the leg. It occurs in approximately 1 in 1,000 people. If left untreated, the clot can travel up to the lungs and cause a potentially life-threatening pulmonary embolism (PE). Previously, a DVT was treated with the anticoagulants heparin and vitamin K antagonists. However, two forms of novel oral anticoagulants (NOACs) have been developed: oral direct thrombin inhibitors (DTI) and oral factor Xa inhibitors. The new drugs have characteristics that may be favourable over conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or re-dosing and few known drug interactions. To date, no Cochrane review has measured the effectiveness and safety of these drugs in the treatment of DVT. To assess the effectiveness of oral DTIs and oral factor Xa inhibitors for the treatment of DVT. The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched January 2015) and the Cochrane Register of Studies (last searched January 2015). We searched clinical trials databases for details of ongoing or unpublished studies and the reference lists of relevant articles retrieved by electronic searches for additional citations. We included randomised controlled trials in which people with a DVT confirmed by standard imaging techniques, were allocated to receive an oral DTI or an oral factor Xa inhibitor for the treatment of DVT. Two review authors (LR, JM) independently extracted the data and assessed the risk of bias in the trials. Any disagreements were resolved by discussion with the third review author (PK). We performed meta-analyses when we considered heterogeneity low. The two primary outcomes were recurrent VTE and PE. Other outcomes included all-cause mortality and major bleeding. We calculated all outcomes using an odds ratio (OR) with a 95% confidence interval (CI). We included

Inhibitors of histone demethylases

DEFF Research Database (Denmark)

Lohse, Brian; Kristensen, Jesper L; Kristensen, Line H

2011-01-01

Methylated lysines are important epigenetic marks. The enzymes involved in demethylation have recently been discovered and found to be involved in cancer development and progression. Despite the relative recent discovery of these enzymes a number of inhibitors have already appeared. Most of the i...

The Use of Plasma-Derived Complement C1-Esterase Inhibitor Concentrate (Berinert®) in the Treatment of Angiotensin Converting Enzyme-Inhibitor Related Angioedema

DEFF Research Database (Denmark)

Hermanrud, Thorbjørn; Duus, Nicolaj; Bygum, Anette

2016-01-01

Angioedema of the upper airways is a severe and potentially life-threatening condition. The incidence has been increasing in the past two decades, primarily due to pharmaceuticals influencing the generation or degradation of the vasoactive molecule bradykinin. Plasma-derived C1-esterase inhibitor...... concentrate is a well-established treatment option of hereditary and acquired complement C1-esterase inhibitor deficiency, which are also mediated by an increased level of bradykinin resulting in recurrent angioedema. We here present a case of severe angiotensin converting enzyme-inhibitor related angioedema...

Blocking the proliferation of human tumor cell lines by peptidase inhibitors from Bauhinia seeds.

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Nakahata, Adriana Miti; Mayer, Barbara; Neth, Peter; Hansen, Daiane; Sampaio, Misako Uemura; Oliva, Maria Luiza Vilela

2013-03-01

In cancer tumors, growth, invasion, and formation of metastasis at a secondary site play a pivotal role, participating in diverse processes in the development of the pathology, such as degradation of extracellular matrix. Bauhinia seeds contain relatively large quantities of peptidase inhibitors, and two Bauhinia inhibitors were obtained in a recombinant form from the Bauhinia bauhinioides species, B. bauhinoides cruzipain inhibitor, which is a cysteine and serine peptidase inhibitor, and B. bauhinioides kallikrein inhibitor, which is a serine peptidase inhibitor. While recombinant B. bauhinoides cruzipain inhibitor inhibits human neutrophil elastase cathepsin G and the cysteine proteinase cathepsin L, recombinant B. bauhinioides kallikrein inhibitor inhibits plasma kallikrein and plasmin. The effects of recombinant B. bauhinoides cruzipain inhibitor and recombinant B. bauhinioides kallikrein inhibitor on the viability of tumor cell lines with a distinct potential of growth from the same tissue were compared to those of the clinical cytotoxic drug 5-fluorouracil. At 12.5 µM concentration, recombinant B. bauhinoides cruzipain inhibitor and recombinant B. bauhinioides kallikrein inhibitor were more efficient than 5-fluorouracil in inhibiting MKN-28 and Hs746T (gastric), HCT116 and HT29 (colorectal), SkBr-3 and MCF-7 (breast), and THP-1 and K562 (leukemia) cell lines. Additionally, recombinant B. bauhinoides cruzipain inhibitor inhibited 40 % of the migration of Hs746T, the most invasive gastric cell line, while recombinant B. bauhinioides kallikrein inhibitor did not affect cell migration. Recombinant B. bauhinioides kallikrein inhibitor and recombinant B. bauhinoides cruzipain inhibitor, even at high doses, did not affect hMSC proliferation while 5-fluorouracil greatly reduced the proliferation rates of hMSCs. Therefore, both recombinant B. bauhinoides cruzipain inhibitor and recombinant B. bauhinioides kallikrein inhibitor might be considered for further studies

Novel endogenous angiogenesis inhibitors and their therapeutic potential.

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Rao, Nithya; Lee, Yu Fei; Ge, Ruowen

2015-10-01

Angiogenesis, the formation of new blood vessels from the pre-existing vasculature is essential for embryonic development and tissue homeostasis. It also plays critical roles in diseases such as cancer and retinopathy. A delicate balance between pro- and anti-angiogenic factors ensures normal physiological homeostasis. Endogenous angiogenesis inhibitors are proteins or protein fragments that are formed in the body and have the ability to limit angiogenesis. Many endogenous angiogenesis inhibitors have been discovered, and the list continues to grow. Endogenous protein/peptide inhibitors are relatively less toxic, better tolerated and have a lower risk of drug resistance, which makes them attractive as drug candidates. In this review, we highlight ten novel endogenous protein angiogenesis inhibitors discovered within the last five years, including ISM1, FKBPL, CHIP, ARHGAP18, MMRN2, SOCS3, TAp73, ZNF24, GPR56 and JWA. Although some of these proteins have been well characterized for other biological functions, we focus on their new and specific roles in angiogenesis inhibition and discuss their potential for therapeutic application.

A thermostable serralysin inhibitor from marine bacterium Flavobacterium sp. YS-80-122

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Liang, Pengjuan; Li, Shangyong; Wang, Kun; Wang, Fang; Xing, Mengxin; Hao, Jianhua; Sun, Mi

2018-03-01

Serralysin inhibitors have been proposed as potent drugs against many diseases and may help to prevent further development of antibiotic-resistant pathogenic bacteria. In this study, a novel serralysin inhibitor gene, lupI, was cloned from the marine bacterium Flavobacterium sp. YS-80-122 and expressed in Escherichia coli. The deduced serralysin inhibitor, LupI, shows <40% amino acid identity to other reported serralysin inhibitors. Multiple sequence alignment and phylogenetic analysis of LupI with other serralysin inhibitors indicated that LupI was a novel type of serralysin inhibitor. The inhibitory constant for LupI towards its target metalloprotease was 0.64 μmol/L. LupI was thermostable at high temperature, in which 35.6%-90.7% of its inhibitory activity was recovered after treatment at 100°C for 1-60 min followed by incubation at 0°C. This novel inhibitor may represent a candidate drug for the treatment of serralysin-related infections.

Metabolic responses in Candida tropicalis to complex inhibitors during xylitol bioconversion.

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Wang, Shizeng; Li, Hao; Fan, Xiaoguang; Zhang, Jingkun; Tang, Pingwah; Yuan, Qipeng

2015-09-01

During xylitol fermentation, Candida tropicalis is often inhibited by inhibitors in hemicellulose hydrolysate. The mechanisms involved in the metabolic responses to inhibitor stress and the resistances to inhibitors are still not clear. To understand the inhibition mechanisms and the metabolic responses to inhibitors, a GC/MS-based metabolomics approach was performed on C. tropicalis treated with and without complex inhibitors (CI, including furfural, phenol and acetic acid). Partial least squares discriminant analysis was used to determine the metabolic variability between CI-treated groups and control groups, and 25 metabolites were identified as possible entities responsible for the discrimination caused by inhibitors. We found that xylose uptake rate and xylitol oxidation rate were promoted by CI treatment. Metabolomics analysis showed that the flux from xylulose to pentose phosphate pathway increased, and tricarboxylic acid cycle was disturbed by CI. Moreover, the changes in levels of 1,3-propanediol, trehalose, saturated fatty acids and amino acids showed different mechanisms involved in metabolic responses to inhibitor stress. The increase of 1,3-propanediol was considered to be correlated with regulating redox balance and osmoregulation. The increase of trehalose might play a role in protein stabilization and cellular membranes protection. Saturated fatty acids could cause the decrease of membrane fluidity and make the plasma membrane rigid to maintain the integrity of plasma membrane. The deeper understanding of the inhibition mechanisms and the metabolic responses to inhibitors will provide us with more information on the metabolism regulation during xylitol bioconversion and the construction of industrial strains with inhibitor tolerance for better utilization of bioresource. Copyright © 2015 Elsevier Inc. All rights reserved.

Synergistic interactions between HDAC and sirtuin inhibitors in human leukemia cells.

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Michele Cea

Full Text Available Aberrant histone deacetylase (HDAC activity is frequent in human leukemias. However, while classical, NAD(+-independent HDACs are an established therapeutic target, the relevance of NAD(+-dependent HDACs (sirtuins in leukemia treatment remains unclear. Here, we assessed the antileukemic activity of sirtuin inhibitors and of the NAD(+-lowering drug FK866, alone and in combination with traditional HDAC inhibitors. Primary leukemia cells, leukemia cell lines, healthy leukocytes and hematopoietic progenitors were treated with sirtuin inhibitors (sirtinol, cambinol, EX527 and with FK866, with or without addition of the HDAC inhibitors valproic acid, sodium butyrate, and vorinostat. Cell death was quantified by propidium iodide cell staining and subsequent flow-cytometry. Apoptosis induction was monitored by cell staining with FITC-Annexin-V/propidium iodide or with TMRE followed by flow-cytometric analysis, and by measuring caspase3/7 activity. Intracellular Bax was detected by flow-cytometry and western blotting. Cellular NAD(+ levels were measured by enzymatic cycling assays. Bax was overexpressed by retroviral transduction. Bax and SIRT1 were silenced by RNA-interference. Sirtuin inhibitors and FK866 synergistically enhanced HDAC inhibitor activity in leukemia cells, but not in healthy leukocytes and hematopoietic progenitors. In leukemia cells, HDAC inhibitors were found to induce upregulation of Bax, a pro-apoptotic Bcl2 family-member whose translocation to mitochondria is normally prevented by SIRT1. As a result, leukemia cells become sensitized to sirtuin inhibitor-induced apoptosis. In conclusion, NAD(+-independent HDACs and sirtuins cooperate in leukemia cells to avoid apoptosis. Combining sirtuin with HDAC inhibitors results in synergistic antileukemic activity that could be therapeutically exploited.

SGLT2 Inhibitors as a Therapeutic Option for Diabetic Nephropathy

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Daiji Kawanami

2017-05-01

Full Text Available Diabetic nephropathy (DN is a major cause of end-stage renal disease (ESRD worldwide. Glycemic and blood pressure (BP control are important but not sufficient to attenuate the incidence and progression of DN. Sodium–glucose cotransporter (SGLT 2 inhibitors are a new class of glucose-lowering agent suggested to exert renoprotective effects in glucose lowering-dependent and independent fashions. Experimental studies have shown that SGLT2 inhibitors attenuate DN in animal models of both type 1 diabetes (T1D and type 2 diabetes (T2D, indicating a potential renoprotective effect beyond glucose reduction. Renoprotection by SGLT2 inhibitors has been demonstrated in T2D patients with a high cardiovascular risk in randomized controlled trials (RCTs. These favorable effects of SGLT2 inhibitors are explained by several potential mechanisms, including the attenuation of glomerular hyperfiltration, inflammation and oxidative stress. In this review article, we discuss the renoprotective effects of SGLT2 inhibitors by integrating experimental findings with the available clinical data.

SGLT2 Inhibitors as a Therapeutic Option for Diabetic Nephropathy.

Science.gov (United States)

Kawanami, Daiji; Matoba, Keiichiro; Takeda, Yusuke; Nagai, Yosuke; Akamine, Tomoyo; Yokota, Tamotsu; Sango, Kazunori; Utsunomiya, Kazunori

2017-05-18

Diabetic nephropathy (DN) is a major cause of end-stage renal disease (ESRD) worldwide. Glycemic and blood pressure (BP) control are important but not sufficient to attenuate the incidence and progression of DN. Sodium-glucose cotransporter (SGLT) 2 inhibitors are a new class of glucose-lowering agent suggested to exert renoprotective effects in glucose lowering-dependent and independent fashions. Experimental studies have shown that SGLT2 inhibitors attenuate DN in animal models of both type 1 diabetes (T1D) and type 2 diabetes (T2D), indicating a potential renoprotective effect beyond glucose reduction. Renoprotection by SGLT2 inhibitors has been demonstrated in T2D patients with a high cardiovascular risk in randomized controlled trials (RCTs). These favorable effects of SGLT2 inhibitors are explained by several potential mechanisms, including the attenuation of glomerular hyperfiltration, inflammation and oxidative stress. In this review article, we discuss the renoprotective effects of SGLT2 inhibitors by integrating experimental findings with the available clinical data.

Substrate and inhibitor specificity of kynurenine monooxygenase from Cytophaga hutchinsonii.

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Phillips, Robert S; Anderson, Andrew D; Gentry, Harvey G; Güner, Osman F; Bowen, J Phillip

2017-04-15

Kynurenine monooxygenase (KMO) is a potential drug target for treatment of neurodegenerative disorders such as Huntington's and Alzheimer's diseases. We have evaluated substituted kynurenines as substrates or inhibitors of KMO from Cytophaga hutchinsonii. Kynurenines substituted with a halogen at the 5-position are excellent substrates, with values of k cat and k cat /K m comparable to or higher than kynurenine. However, kynurenines substituted in the 3-position are competitive inhibitors, with K I values lower than the K m for kynurenine. Bromination also enhances inhibition, and 3,5-dibromokynurenine is a potent competitive inhibitor with a K I value of 1.5μM. A pharmacophore model of KMO was developed, and predicted that 3,4-dichlorohippuric acid would be an inhibitor. The K I for this compound was found to be 34μM, thus validating the pharmacophore model. We are using these results and our model to design more potent inhibitors of KMO. Copyright © 2017 Elsevier Ltd. All rights reserved.

Further developments and field deployment of phosphorus functionalized polymeric scale inhibitors

Energy Technology Data Exchange (ETDEWEB)

Todd, Malcolm J.; Thornton, Alex R.; Wylde, Jonathan J.; Strachan, Catherine J.; Moir, Gordon [Clariant Oil Services, Muttenz (Switzerland); Goulding, John [John Goulding Consultancy, York (United Kingdom)

2012-07-01

As the oil and gas industry strives to replace ageing, environmentally undesirable scale inhibitors there is an ever increasing use of polymeric inhibitors. The incorporation of phosphorous functionality into a polymer backbone has been shown to improve inhibition efficiency, enhance adsorption characteristics and allow the polymer concentration to be analyzed by elemental phosphorus. It is known that some phosphorus tagged polymers can be problematic to analyze in oil field brines as they typically have a low phosphorus content which is difficult to determine from the background. The development of novel phosphorus functionalized polymeric scale inhibitors was previously described (IBP3530-10). This paper follows the development of the inhibitor class. Utilizing extensive laboratory testing the interactive nature of the scale inhibitors and reservoir lithology was studied. These novel phosphorus functionalized inhibitors were compared to a number of other available scale inhibitors. The incorporation of phosphorus functionality into polymeric inhibitors can be expensive utilizing traditional methods as the phosphorus containing monomers are the financially limiting factor. These are typically vinyl phosphonic acid (VPA), or vinyl diphosphonic acid (VDPA). The novel phosphorus functionalized monomers utilized herein are simpler to manufacture allowing higher phosphorus content within the polymer backbone. The addition of phosphorus into a polymer backbone has previously been known to exacerbate analysis issues in some commercially available scale inhibitors. This is due to incomplete polymerization reactions leaving free and/or inorganic phosphorus containing moieties which can interfere with the analysis, or low levels of phosphorus within end-capped polymers can make it difficult to determine the active concentration accurately within field brines which contain many impuritie. Polymeric inhibitors are known to contain a range of molecular weights with varying

The effects of GLP-1 analogues, DPP-4 inhibitors and SGLT2 inhibitors on the renal system.

Science.gov (United States)

Schernthaner, Guntram; Mogensen, Carl Erik; Schernthaner, Gerit-Holger

2014-09-01

Diabetic nephropathy (DN) affects an estimated 20%-40% of patients with type 2 diabetes mellitus (T2DM). Key modifiable risk factors for DN are albuminuria, anaemia, dyslipidaemia, hyperglycaemia and hypertension, together with lifestyle factors, such as smoking and obesity. Early detection and treatment of these risk factors can prevent DN or slow its progression, and may even induce remission in some patients. DN is generally preceded by albuminuria, which frequently remains elevated despite treatment in patients with T2DM. Optimal treatment and prevention of DN may require an early, intensive, multifactorial approach, tailored to simultaneously target all modifiable risk factors. Regular monitoring of renal function, including urinary albumin excretion, creatinine clearance and glomerular filtration rate, is critical for following any disease progression and making treatment adjustments. Dipeptidyl peptidase (DPP)-4 inhibitors and sodium-glucose cotransporter 2 (SGLT2) inhibitors lower blood glucose levels without additional risk of hypoglycaemia, and may also reduce albuminuria. Further investigation of the potential renal benefits of DPP-4 and SGLT2 inhibitors is underway. © The Author(s) 2014.

Novel guanidine-based inhibitors of inosine monophosphate dehydrogenase.

Science.gov (United States)

Iwanowicz, Edwin J; Watterson, Scott H; Liu, Chunjian; Gu, Henry H; Mitt, Toomas; Leftheris, Katerina; Barrish, Joel C; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Hollenbaugh, Diane L

2002-10-21

A series of novel guanidine-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. IMPDH catalyzes the rate determining step in guanine nucleotide biosynthesis and is a target for anticancer, immunosuppressive and antiviral therapy. The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for this new series of inhibitors is given.

Structure-Guided Strategy for the Development of Potent Bivalent ERK Inhibitors

Energy Technology Data Exchange (ETDEWEB)

Lechtenberg, Bernhard C. [Cancer; Mace, Peter D. [Cancer; Sessions, E. Hampton [Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida 32827, United States; Williamson, Robert [Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida 32827, United States; Stalder, Romain [Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida 32827, United States; Wallez, Yann [Cancer; Roth, Gregory P. [Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida 32827, United States; Riedl, Stefan J. [Cancer; Pasquale, Elena B. [Cancer; Pathology

2017-06-13

ERK is the effector kinase of the RAS-RAF-MEK-ERK signaling cascade, which promotes cell transformation and malignancy in many cancers and is thus a major drug target in oncology. Kinase inhibitors targeting RAF or MEK are already used for the treatment of certain cancers, such as melanoma. Although the initial response to these drugs can be dramatic, development of drug resistance is a major challenge, even with combination therapies targeting both RAF and MEK. Importantly, most resistance mechanisms still rely on activation of the downstream effector kinase ERK, making it a promising target for drug development efforts. Here, we report the design and structural/functional characterization of a set of bivalent ERK inhibitors that combine a small molecule inhibitor that binds to the ATP-binding pocket with a peptide that selectively binds to an ERK protein interaction surface, the D-site recruitment site (DRS). Our studies show that the lead bivalent inhibitor, SBP3, has markedly improved potency compared to the small molecule inhibitor alone. Unexpectedly, we found that SBP3 also binds to several ERK-related kinases that contain a DRS, highlighting the importance of experimentally verifying the predicted specificity of bivalent inhibitors. However, SBP3 does not target any other kinases belonging to the same CMGC branch of the kinome. Additionally, our modular click chemistry inhibitor design facilitates the generation of different combinations of small molecule inhibitors with ERK-targeting peptides.

Health economics of treating haemophilia A with inhibitors.

Science.gov (United States)

Knight, C

2005-11-01

Haemophilia is a rare, inherited blood disorder in which blood clotting is impaired such that patients suffer from excessive internal and external bleeding. At present there is no cure for haemophilia A and patients require expensive, life-long treatment involving clotting factor replacement therapy. Treatment costs are perceived to be higher for patients who have developed inhibitory antibodies to factor VIII, the standard therapy for haemophilia A. However, initial cost analyses suggest that clotting factor therapy with alternative haemostatic agents, such as recombinant activated factor VII or activated prothrombin complex concentrate, is no more expensive for the majority of haemophilia A patients with inhibitors than for those without inhibitors. With the availability of effective alternative haemostatic agents, orthopaedic surgery for haemophilia A patients with inhibitors is now a clinical option, and initial cost analyses suggest this may be a cost-effective treatment strategy for patients with inhibitors whose quality of life (QoL) is severely impaired by joint arthropathy. In an era of finite healthcare resourcing it is important to determine whether new treatments justify higher unit costs compared with standard therapies and whether such higher costs are justified from an individual perspective in terms of improved QoL, and from a societal perspective in terms of improved productivity and reduced overall healthcare costs. This paper examines current data on the health economics of treating haemophilia A patients with inhibitors, focusing on the overall costs of clotting factor replacement therapy and the cost consequences of joint replacement.

Histone deacetylase inhibitors augment doxorubicin-induced DNA damage in cardiomyocytes.

Science.gov (United States)

Ververis, Katherine; Rodd, Annabelle L; Tang, Michelle M; El-Osta, Assam; Karagiannis, Tom C

2011-12-01

Histone deacetylase inhibitors have emerged as a new class of anticancer therapeutics with suberoylanilide hydroxamic acid (Vorinostat) and depsipeptide (Romidepsin) already being approved for clinical use. Numerous studies have identified that histone deacetylase inhibitors will be most effective in the clinic when used in combination with conventional cancer therapies such as ionizing radiation and chemotherapeutic agents. One promising combination, particularly for hematologic malignancies, involves the use of histone deacetylase inhibitors with the anthracycline, doxorubicin. However, we previously identified that trichostatin A can potentiate doxorubicin-induced hypertrophy, the dose-limiting side-effect of the anthracycline, in cardiac myocytes. Here we have the extended the earlier studies and evaluated the effects of combinations of the histone deacetylase inhibitors, trichostatin A, valproic acid and sodium butyrate on doxorubicin-induced DNA double-strand breaks in cardiomyocytes. Using γH2AX as a molecular marker for the DNA lesions, we identified that all of the broad-spectrum histone deacetylase inhibitors tested augment doxorubicin-induced DNA damage. Furthermore, it is evident from the fluorescence photomicrographs of stained nuclei that the histone deacetylase inhibitors also augment doxorubicin-induced hypertrophy. These observations highlight the importance of investigating potential side-effects, in relevant model systems, which may be associated with emerging combination therapies for cancer.

Changes in glucose-induced plasma active glucagon-like peptide-1 levels by co-administration of sodium–glucose cotransporter inhibitors with dipeptidyl peptidase-4 inhibitors in rodents

Directory of Open Access Journals (Sweden)

Takahiro Oguma

2016-12-01

Full Text Available We investigated whether structurally different sodium–glucose cotransporter (SGLT 2 inhibitors, when co-administered with dipeptidyl peptidase-4 (DPP4 inhibitors, could enhance glucagon-like peptide-1 (GLP-1 secretion during oral glucose tolerance tests (OGTTs in rodents. Three different SGLT inhibitors—1-(β-d-Glucopyranosyl-4-chloro-3-[5-(6-fluoro-2-pyridyl-2-thienylmethyl]benzene (GTB, TA-1887, and canagliflozin—were examined to assess the effect of chemical structure. Oral treatment with GTB plus a DPP4 inhibitor enhanced glucose-induced plasma active GLP-1 (aGLP-1 elevation and suppressed glucose excursions in both normal and diabetic rodents. In DPP4-deficient rats, GTB enhanced glucose-induced aGLP-1 elevation without affecting the basal level, whereas metformin, previously reported to enhance GLP-1 secretion, increased both the basal level and glucose-induced elevation. Oral treatment with canagliflozin and TA-1887 also enhanced glucose-induced aGLP-1 elevation when co-administered with either teneligliptin or sitagliptin. These data suggest that structurally different SGLT2 inhibitors enhance plasma aGLP-1 elevation and suppress glucose excursions during OGTT when co-administered with DPP4 inhibitors, regardless of the difference in chemical structure. Combination treatment with DPP4 inhibitors and SGLT2 inhibitors having moderate SGLT1 inhibitory activity may be a promising therapeutic option for improving glycemic control in patients with type 2 diabetes mellitus.

The efficiency of a corrosion inhibitor on steel in a simulated concrete environment

Energy Technology Data Exchange (ETDEWEB)

Gartner, Nina; Kosec, Tadeja, E-mail: tadeja.kosec@zag.si; Legat, Andraž

2016-12-01

The aim of the present work was to characterize the efficiency of a corrosion inhibitor on steel in a simulated concrete pore solution. Laboratory measurements were performed at various chloride and inhibitor concentrations in order to simulate different applications of the inhibitor when used for the protection or rehabilitation of steel reinforcement in concrete. Two electrochemical techniques, i.e. potentiodynamic polarization scans and electrochemical impedance spectroscopy, were used for this study. The exposed surfaces of the steel specimens were subsequently investigated by Raman spectroscopy and scanning electron microscopy. It was found that the inhibitor can efficiently retard the corrosion of steel in a simulated concrete pore solution at concentrations of the inhibitor >2.0% and of chlorides <0.3% at a pH 10.5. On the other hand, when these conditions are not fulfilled, localized corrosion was observed. The results of the Raman and SEM/EDS analysis showed various morphologies of corrosion products and different types of corrosion attack depending on the pH of the pore solution, and the applied concentrations of the chlorides and the inhibitor. - Highlights: • Electrochemical studies performed at various Cl{sup −} and inhibitor concentrations. • Exposed steel surfaces investigated by Raman spectroscopy and SEM. • Cl{sup −}/inhibitor ratio is important parameter for the inhibitor's efficiency. • The corrosion can re-occur if the concentration of the inhibitor is reduced. • Different corrosion behaviour and oxides in the presence of inhibitor and/or Cl{sup −}.

Rapid detection and subtyping of European swine influenza viruses in porcine clinical samples by haemagglutinin- and neuraminidase-specific tetra- and triplex real-time RT-PCRs.

Science.gov (United States)

Henritzi, Dinah; Zhao, Na; Starick, Elke; Simon, Gaelle; Krog, Jesper S; Larsen, Lars Erik; Reid, Scott M; Brown, Ian H; Chiapponi, Chiara; Foni, Emanuela; Wacheck, Silke; Schmid, Peter; Beer, Martin; Hoffmann, Bernd; Harder, Timm C

2016-11-01

A diversifying pool of mammalian-adapted influenza A viruses (IAV) with largely unknown zoonotic potential is maintained in domestic swine populations worldwide. The most recent human influenza pandemic in 2009 was caused by a virus with genes originating from IAV isolated from swine. Swine influenza viruses (SIV) are widespread in European domestic pig populations and evolve dynamically. Knowledge regarding occurrence, spread and evolution of potentially zoonotic SIV in Europe is poorly understood. Efficient SIV surveillance programmes depend on sensitive and specific diagnostic methods which allow for cost-effective large-scale analysis. New SIV haemagglutinin (HA) and neuraminidase (NA) subtype- and lineage-specific multiplex real-time RT-PCRs (RT-qPCR) have been developed and validated with reference virus isolates and clinical samples. A diagnostic algorithm is proposed for the combined detection in clinical samples and subtyping of SIV strains currently circulating in Europe that is based on a generic, M-gene-specific influenza A virus RT-qPCR. In a second step, positive samples are examined by tetraplex HA- and triplex NA-specific RT-qPCRs to differentiate the porcine subtypes H1, H3, N1 and N2. Within the HA subtype H1, lineages "av" (European avian-derived), "hu" (European human-derived) and "pdm" (human pandemic A/H1N1, 2009) are distinguished by RT-qPCRs, and within the NA subtype N1, lineage "pdm" is differentiated. An RT-PCR amplicon Sanger sequencing method of small fragments of the HA and NA genes is also proposed to safeguard against failure of multiplex RT-qPCR subtyping. These new multiplex RT-qPCR assays provide adequate tools for sustained SIV monitoring programmes in Europe. © 2016 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

Dry eye syndrome in aromatase inhibitor users.

Science.gov (United States)

Turaka, Kiran; Nottage, Jennifer M; Hammersmith, Kristin M; Nagra, Parveen K; Rapuano, Christopher J

2013-04-01

Aromatase inhibitors are frequently used as an adjuvant therapy in the treatment of breast cancer. We observed that several patients taking aromatase inhibitors presented with severe dry eye symptoms, and we investigated whether there is a relationship between aromatase inhibitors and dry eyes in these patients. Retrospective chart review. Forty-one women. A computerized search of health records was performed to identify patients using anastrazole, letrozole and exemestane seen by the Cornea Service from August 2008 to March 2011. The results were compared with age-matched controls. Ocular surface changes among aromatase inhibitors users. Of the 41 women, 39 were Caucasians. Thirty-nine patients had breast cancer (95%), one patient had ovarian cancer (2.5%) and one had an unknown primary cancer. Mean age was 68 ± 11.3 years (range 47-95). Most common presenting symptoms were blurred vision in 28 (68%) patients, irritation/foreign body sensation in 12 (29%) patients, redness in 9 (22%) patients, tearing in 6 (22%) patients and photosensitivity in 2 (5%) patients. Mean Schirmer's test measurement was 11 ± 5.8 mm (range 0.5-20 mm). Blepharitis was noted in 68 of 82 eyes (73%), decreased or poor tear function in 24 eyes (29%), conjunctival injection in 18 eyes (22%) and superficial punctate keratitis in 12 eyes (29%). Among an age-matched population (45-95 years), dry eye syndrome was found in only 9.5% of patients. Because the prevalence of ocular surface disease signs and symptoms appears to be higher in study group than control patients, aromatase inhibitors might be a contributing factor to the dry eye symptoms. © 2012 The Authors. Clinical and Experimental Ophthalmology © 2012 Royal Australian and New Zealand College of Ophthalmologists.

Peptide-Based Selective Inhibitors of Matrix Metalloproteinase-Mediated Activities

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Margaret W. Ndinguri

2012-11-01

Full Text Available The matrix metalloproteinases (MMPs exhibit a broad array of activities, some catalytic and some non-catalytic in nature. An overall lack of selectivity has rendered small molecule, active site targeted MMP inhibitors problematic in execution. Inhibitors that favor few or individual members of the MMP family often take advantage of interactions outside the enzyme active site. We presently focus on peptide-based MMP inhibitors and probes that do not incorporate conventional Zn2+ binding groups. In some cases, these inhibitors and probes function by binding only secondary binding sites (exosites, while others bind both exosites and the active site. A myriad of MMP mediated-activities beyond selective catalysis can be inhibited by peptides, particularly cell adhesion, proliferation, motility, and invasion. Selective MMP binding peptides comprise highly customizable, unique imaging agents. Areas of needed improvement for MMP targeting peptides include binding affinity and stability.

Effects of protease inhibitors on radiation transformation in vitro

International Nuclear Information System (INIS)

Kennedy, A.R.; Little, J.B.

1981-01-01

We have investigated the effects of three protease inhibitors, antipain, leupeptin, and soybean trypsin inhibitor, on the induction of oncogenic transformation in mouse C3H10T 1/2 cells by X-rays. The patterns of inhibition by the three protease inhibitors were different. Antipain was the most effective, having the ability to suppress completely radiation transformation as well as radiation transformation enhanced by the phorbol ester promoting agent 12-O-tetradecanoylphorbol-13-acetate. The fact that antipain could suppress transformation when present for only 1 day following irradiation suggests that an effect on a DNA repair process might be important in its action. Leupeptin was less effective than antipain in its inhibition of radiation transformation. Soybean trypsin inhibitor suppressed only the promotional effects of 12-O-tetradecanoylphorbol-13-acetate on transformation. Our results suggest that there may be more than one protease involved in carcinogenesis

Tubulin Inhibitor-Based Antibody-Drug Conjugates for Cancer Therapy

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Hao Chen

2017-08-01

Full Text Available Antibody-drug conjugates (ADCs are a class of highly potent biopharmaceutical drugs generated by conjugating cytotoxic drugs with specific monoclonal antibodies through appropriate linkers. Specific antibodies used to guide potent warheads to tumor tissues can effectively reduce undesired side effects of the cytotoxic drugs. An in-depth understanding of antibodies, linkers, conjugation strategies, cytotoxic drugs, and their molecular targets has led to the successful development of several approved ADCs. These ADCs are powerful therapeutics for cancer treatment, enabling wider therapeutic windows, improved pharmacokinetic/pharmacodynamic properties, and enhanced efficacy. Since tubulin inhibitors are one of the most successful cytotoxic drugs in the ADC armamentarium, this review focuses on the progress in tubulin inhibitor-based ADCs, as well as lessons learned from the unsuccessful ADCs containing tubulin inhibitors. This review should be helpful to facilitate future development of new generations of tubulin inhibitor-based ADCs for cancer therapy.

Comparison of Clot-based, Chromogenic, and Fluorescence Assays for Measurement of Factor VIII Inhibitors in the U.S. Hemophilia Inhibitor Research Study

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Miller, Connie H.; Rice, Anne S.; Boylan, Brian; Shapiro, Amy D.; Lentz, Steven R.; Wicklund, Brian M.; Kelly, Fiona M.; Soucie, J. Michael

2015-01-01

Summary Background Detection and validation of inhibitors (antibodies) to hemophilia treatment products are important for clinical care, evaluation of product safety, and assessment of population trends. Methods Centralized monitoring for factor VIII (FVIII) inhibitors was conducted for patients in the Hemophilia Inhibitor Research Study using a previously reported modified Nijmegen-Bethesda clotting assay (NBA), a chromogenic Bethesda assay (CBA), and a novel fluorescence immunoassay (FLI). Results NBA and CBA were performed on 1005 specimens and FLI on 272 specimens. CBA was negative on 880/883 specimens (99.7%) with Nijmegen-Bethesda units (NBU)NBA and negative CBA, 58.1% were FLI-negative, 12.9% had evidence of lupus anticoagulant, and 35.5% had non-time-dependent inhibition. CBA and FLI were positive on 72.4% and 100% of 1.0–1.9 NBU specimens and 43.1% and 50.0% of 0.5–0.9 NBU specimens. FLI detected antibodies in 98.0% of CBA-positive and 81.6% of NBA-positive specimens (P=0.004). Among 21 new inhibitors detected by NBA, 5 (23.8%) with 0.7–1.3 NBU did not react in CBA or FLI. Among previously positive patients with 0.5–1.9 NBU, 7/25 (28%) were not CBA or FLI positive. FLI was positive on 36/169 NBU-negative specimens (21.3%). Conclusions FVIII specificity could not be demonstrated by CBA or FLI for 26% of inhibitors of 0.5–1.9 NBU; such results must be interpreted with caution. Low titer inhibitors detected in clot-based assays should always be repeated, with consideration given to evaluating their reactivity with FVIII using more specific assays. PMID:23601690

Congenital ventricular septal defects and prenatal exposure to cyclooxygenase inhibitors

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F. Burdan

2006-07-01

Full Text Available Ventricular septal defects (VSDs are common congenital abnormalities which have been reported to be associated with maternal fever and various environmental factors. The aim of the present study was to evaluate the effect of prenatal exposure to cyclooxygenase (COX inhibitors on heart defects. A retrospective statistical analysis was performed using data collected in our laboratory during various teratological studies carried out on albino CRL:(WIWUBR Wistar strain rats from 1997 to 2004. The observations were compared with concurrent and historic control data, as well as findings from other developmental toxicological studies with selective and nonselective COX-2 inhibitors. Despite the lack of significant differences in the frequency of VSDs between drug-exposed and control groups, statistical analysis by the two-sided Mantel-Haenszel test and historical control data showed a higher incidence of heart defects in offspring exposed to nonselective COX inhibitors (30.06/10,000. Unlike other specific inhibitors, aspirin (46.26/10,000 and ibuprofen (106.95/10,000 significantly increased the incidence of the VSD when compared with various control groups (5.38-19.72/10,000. No significant differences in length or weight were detected between fetuses exposed to COX inhibitors and born with VSD and non-malformed offsprings. However, a statistically significant increase of fetal body length and decrease of body mass index were found in fetuses exposed to COX inhibitors when compared with untreated control. We conclude that prenatal exposure to COX inhibitors, especially aspirin and ibuprofen, increased the incidence of VSDs in rat offspring but was not related to fetal growth retardation.

Inhibitors of mTOR

NARCIS (Netherlands)

Klümpen, Heinz-Josef; Beijnen, Jos H.; Gurney, Howard; Schellens, Jan H. M.

2010-01-01

Inhibitors of mammalian target of rapamycin (mTOR) have been approved for the treatment of renal cell carcinoma and appear to have a role in the treatment of other malignancies. The primary objective of this drug review is to provide pharmacokinetic and dynamic properties of the commonly used drugs

Reverse zymography alone does not confirm presence of a protease inhibitor.

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Dutta, Sangita; Bhattacharyya, Debasish

2013-03-01

Reverse zymography is applied for identification and semi-quantification of protease inhibitors that are of protein in nature. However, a protein that shows band in reverse zymography against a protease used for digestion of the gel need not be an inhibitor; it might be resistant to degradation by the protease. We demonstrate that in reverse zymography, avidin, streptavidin and the leaf extract of Catharanthus roseus behave like inhibitors of proteases like papain, ficin, bromelain extracts from pineapple leaf, stem and fruit and trypsin. Still, they do not act as inhibitors of those proteases when enzyme assays were done in solution. In reverse zymography, the extract of pineapple crown leaf shows two major inhibitor bands against its own proteases. Identification of these proteins from sequences derived from MALDI TOF MS analysis indicated that they are fruit and stem bromelains. Avidin, streptavidin and bromelains are 'kinetically stable proteins' that are usually resistant to proteolysis. Thus, it is recommended that identification of an inhibitor of a protease by reverse zymography should be supported by independent assay methods for confirmation.

ERK mutations confer resistance to mitogen-activated protein kinase pathway inhibitors.

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Goetz, Eva M; Ghandi, Mahmoud; Treacy, Daniel J; Wagle, Nikhil; Garraway, Levi A

2014-12-01

The use of targeted therapeutics directed against BRAF(V600)-mutant metastatic melanoma improves progression-free survival in many patients; however, acquired drug resistance remains a major medical challenge. By far, the most common clinical resistance mechanism involves reactivation of the MAPK (RAF/MEK/ERK) pathway by a variety of mechanisms. Thus, targeting ERK itself has emerged as an attractive therapeutic concept, and several ERK inhibitors have entered clinical trials. We sought to preemptively determine mutations in ERK1/2 that confer resistance to either ERK inhibitors or combined RAF/MEK inhibition in BRAF(V600)-mutant melanoma. Using a random mutagenesis screen, we identified multiple point mutations in ERK1 (MAPK3) and ERK2 (MAPK1) that could confer resistance to ERK or RAF/MEK inhibitors. ERK inhibitor-resistant alleles were sensitive to RAF/MEK inhibitors and vice versa, suggesting that the future development of alternating RAF/MEK and ERK inhibitor regimens might help circumvent resistance to these agents. ©2014 American Association for Cancer Research.

[Mechanisms and efficacy of SGLT2 inhibitors].

Science.gov (United States)

Shiba, Teruo

2015-03-01

SGLT2 is a low affinity, high capacity glucose co-transporter, almost exclusively expressed in the kidney cortex. Inhibition of SGLT2 has been shown to increase the daily 50g or more urinary glucose excretion, as compared to placebo, leading to a reduction in blood glucose levels and indicated only for the treatment of type 2 diabetes. In Japan 6 species of SGLT2 inhibitors have already been sold and reported to results in a decrease of FPG by 14.4 to 45.8 (mg/dL), in a reduction of HbA1c by 0.35 to 1.24% and in loss of body weight by 1.29 to 2.50(kg). There is less effect of the SGLT2 inhibitor in diabetic subjects with renal impairment and the reduction in HbA1c and FPG will be approximately half of the average in those with 30 ≤ eGFR ≤ 59. The position of SGLT2 inhibitors would be considered as the drug administered in combination or add-on therapy when the young obese type 2 diabetics without renal impairment has not yet reached to the glycemic target with other drugs although in AACE consensus statement of 2013, it has been shelved for inexperienced use with respect to the positioning of the SGLT2 inhibitors.

Structure of a retro-binding peptide inhibitor complexed with human alpha-thrombin.

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Tabernero, L; Chang, C Y; Ohringer, S L; Lau, W F; Iwanowicz, E J; Han, W C; Wang, T C; Seiler, S M; Roberts, D G; Sack, J S

1995-02-10

The crystallographic structure of the ternary complex between human alpha-thrombin, hirugen and the peptidyl inhibitor Phe-alloThr-Phe-O-CH3, which is acylated at its N terminus with 4-guanidino butanoic acid (BMS-183507), has been determined at 2.6 A resolution. The structure reveals a unique "retro-binding" mode for this tripeptide active site inhibitor. The inhibitor binds with its alkyl-guanidine moiety in the primary specificity pocket and its two phenyl rings occupying the hydrophobic proximal and distal pockets of the thrombin active site. In this arrangement the backbone of the tripeptide forms a parallel beta-strand to the thrombin main-chain at the binding site. This is opposite to the orientation of the natural substrate, fibrinogen, and all the small active site-directed thrombin inhibitors whose bound structures have been previously reported. BMS-183507 is the first synthetic inhibitor proved to bind in a retro-binding fashion to thrombin, in a fashion similar to that of the N-terminal residues of the natural inhibitor hirudin. Furthermore, this new potent thrombin inhibitor (Ki = 17.2 nM) is selective for thrombin over other serine proteases tested and may be a template to be considered in designing hirudin-based thrombin inhibitors with interactions at the specificity pocket.

PI3Kδ inhibitor idelalisib in combination with BTK inhibitor ONO/GS-4059 in diffuse large B cell lymphoma with acquired resistance to PI3Kδ and BTK inhibitors.

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Anella Yahiaoui