bluuebunny/crossref_metadata_2025 huggingface dataset:
Halophenyl Furanopyrimidines as Potent and Selective Anti-VZV Agents
Authors: McGuigan Christopher , Jukes Alison , Blewett Sally , Barucki Hubert , Erichsen Jonathan T , Andrei Graciella , Snoeck Robert , De Clercq Erik , Balzarini Jan
Published: March 2015

Bicyclic furano pyrimidines have been previously reported by us to be highly potent and selective inhibitors of varicella zoster virus (VZV). p-Alkyl phenyl analogues are particularly potent with EC50 values below 1nM. In this article we report the synthesis and anti-VZV activity of a series of halophenyl analogues, with variation in the nature (F, Cl, Br) and location (o, m, p) of the halogen substituent. The compounds show a range of activities from ca. 10 nM to >50 μM. In most cases, ortho substitution leads to greatest activity, meta substitution is in general poor, and the effect of p-substitution shows a marked dependence on the halogen atom. The p-fluorophenyl compound is unique amongst compounds of this class in being inactive as an antiviral. The possible origins of these marked SARs are discussed.
In Vitro and in Vivo Activities of T-705 and Oseltamivir against Influenza Virus
Authors: Takahashi Kazumi , Furuta Yousuke , Fukuda Yoshiko , Kuno Masako , Kamiyama Tomoko , Kozaki Kyo , Nomura Nobuhiko , Egawa Hiroyuki , Minami Shinzaburo , Shiraki Kimiyasu
Published: March 2015

T-705 (6-fluoro-3-hydroxy-2-pyrazinecarboxamide) has a potent and selective inhibitory activity against influenza virus. We studied the effects of an infectious dose on the anti-influenza virus activities of T-705 and oseltamivir, a commercially available neuraminidase inhibitor, both in vitro and in vivo. Plaque formation of influenza A/PR/8/34 virus was completely inhibited by 10 μg/ml of T-705 after 72 h incubation, whereas visible plaque formation was detected in the plate treated with GS 4071, the active form of oseltamivir (10 μg/ml). The antiviral activity of T-705 was not influenced by an increase in multiplicity of infection (MOI) from 0.0001 to 1, but that of GS 4071 was influenced in a yield reduction assay. No increase in viral yield was seen in either culture supernatant or cells after removal of T-705 (10 μg/ml) but, in contrast, productive infection recurred in culture supernatant and in cells after removal of GS 4071. In mice infected with a high challenge dose of influenza A/PR/8/34 virus, orally administered T-705 (200 and 400 mg/kg/day) completely prevented the death of mice and the survival rates of mice were significantly higher than those in mice treated with oseltamivir ( P<0.01). When the treatment was delayed at 1, 13 and 25 h post infection, oral administration of 200 mg/kg of T-705 significantly prevented the death of mice ( P<0.01), and the survival rates of mice treated with T-705 were comparable to those of mice treated with oseltamivir. These results suggest that T-705 has the potential to be a potent inhibitor of human influenza virus infections.
The Substrate Activity of (S)-9-[3-Hydroxy-(2-phosphonomethoxy)Propyl]Adenine Diphosphate toward DNA Polymerases α, δ and ε
Authors: Birkus Gabriel , Rejman Dominik , Otmar Miroslav , Votruba Ivan , Rosenberg Ivan , Holy Antonin
Published: March 2015

In this study, we examined the substrate potency of ( S)-9-[3-hydroxy-(2-phosphonomethoxy)prop-yl]-adenine diphosphate (HPMPApp) toward DNA polymerases α, δ and ε The efficiency of HPMPApp incorporation decreased in the order pol ε >pol δ=pol α and was from 5.4- to 23-fold lower than that of dATP. Depending on which template-primer was used, the HPMPAppKm value was 3.3- and 8.3- (pol α), 3- and 0.82- (pol δ) or 2-fold (pol δ) higher than dATPKm. The ability of HPMPA to accumulate in DNA decreased in the order pol δ >pol α >pol δ. The difference between the elongation rate of DNA with and without one HPMPA molecule at 3′ termini was about 1.1–2.3 fold. The 3′-5′-exonuclease activity of pol δ and ε can excise HPMPA from DNA. These observations indicate that interaction of HPMPApp with pol α, δ and ε may contribute to its cellular toxicity and explain its antiviral activity against polyomavirus.
Effect of Interferon-Alpha and Interferon-Inducers on West Nile Virus in Mouse and Hamster Animal Models
Authors: Morrey John D , Day Craig W , Julander Justin G , Blatt Lawrence M , Smee Donald F , Sidwell Robert W
Published: March 2015

The recent West Nile virus (WNV) outbreak in the United States has increased the need to identify effective therapies. Studies were conducted in cell culture and in rodent animal models to determine the efficacy of interferon-alpha (IFN-α), interferon (IFN) inducers and ribavirin, alone or in combination with IFN, in treating WNV. Intraperitoneal injection of IFN-α B/D (qd for 7 days), polyIpolyC(12)U [Ampligen (every other day for 7 days)] and topically applied imiquimod (qd for 7 days), administered from 1 day before viral challenge, were effective in protecting, respectively, 100%, 100% and 70% of BALB/c mice from mortality induced by subcutaneous injection of WNV. When IFN-α B/D or Ampligen treatments were delayed to 4–6 h before viral challenge in mice, efficacy was greatly diminished. Infected Syrian golden hamsters treated with interferon alphacon-1 (Infergen) and Ampligen 4–6 h before viral challenge gained more weight and had a greater survival than saline-treated animals. A combination study of subcutaneously administered Infergen (5 to 0.05 μg/kg/day) and ribavirin (75 to 7.5 mg/kg/day) in >7 week old hamsters demonstrated that Infergen was slightly efficacious in reducing mortality and disease signs; however, it was not synergistic in its antiviral effects when combined with ribavirin. Ribavirin treatment alone increased mortality of infected hamsters. The reduced mortality correlated with reduced plasma viraemia. Since WNV-infected patients have already been treated with IFN and ribavirin and future clinical trials have been suggested, this first report of IFN alone or in combination with ribavirin in WNV-infected animal models might provide useful information for subsequent treatment of patients.
Potential of 4′-C-Substituted Nucleosides for the Treatment of HIV-1
Authors: Hayakawa Hiroyuki , Kohgo Satoru , Kitano Kenji , Ashida Noriyuki , Kodama Eiichi , Mitsuya Hiroaki , Ohrui Hiroshi
Published: March 2015

Extensive efforts have been made to identify nucleoside reverse transcriptase inhibitors (NRTIs). Eight NRTIs have now been approved for clinical use; however, variants of HIV-1 resistant to these antiviral agents have emerged in patients even when they are treated with combinations [highly active antiretroviral therapy (HAART)]. Thus, the development of novel compounds that are active against drug-resistant HIV-1 variants and that prevent or delay the emergence of resistant HIV-1 variants is urgently needed. Previously, 4′- C-substituted nucleosides (4′-SNs) were designed as new types of NRTIs. They were synthesized and examined as potential therapeutic agents against HIV infection. Among them, several 4′-substituted-2′-deoxynucleosides (4′-SdNs), especially those that bear an ethynyl group, were shown to be active against various laboratory and clinical HIV-1 strains including known drug-resistant variants. These results were recently reported by our collaborators. In this review, we summarize the design, synthesis and demonstrations of the anti-HIV activity of 4′-SNs, and then consider 4′-SNs as potential therapeutic agents for HIV-1.
Mechanisms of HIV Receptor and Co-Receptor Down-Regulation by Prostratin: Role of Conventional and Novel PKC Isoforms
Authors: Hezareh Marjan , Moukil Moulay Ahmed , Szanto Ildiko , Pondarzewski Malgorzata , Mouche Sarah , Cherix Nathalie , Brown Stephen J , Carpentier Jean-Louis , Foti Michelangelo
Published: March 2015

Prostratin is an unusual non-tumour promoting phorbol ester with potential as an inductive adjuvant therapy for highly active antiretroviral therapy (HAART) due to its ability to up-regulate viral expression from latent provirus. In addition, prostratin is also able to inhibit de novo HIV infection most probably because it induces down-regulation of HIV receptors from the surface of target cells. In this study, we investigate the mechanisms by which prostratin down-regulates HIV receptor and co-receptor surface expression in lymphocytic and monocytic cell lines. Our results indicate that prostratin induces down-regulation of surface expression of CD4 and CXCR4, but not CCR5, in various cell lines. Down-regulation of CD4 and CXCR4 by prostratin is achieved by internalization through receptor-mediated endocytosis and/or macropinocytosis, which is then followed by degradation of these molecules. Because prostratin is a protein kinase C (PKC) activator, we next examined the potential contribution of distinct PKC isoforms to down-regulate CD4 and CXCR4 in response to prostratin stimulation. Although exposure of cells to prostratin or phorbol-myristate-acetate (PMA) induces the translocation of several PKC isoforms to the plasma membrane, the use of specific PKC inhibitors revealed that novel PKCs are the main mediators of the prostratin-induced CD4 down-regulation, whereas both conventional and novel PKCs contribute to CXCR4 down-regulation. Altogether these results showed that prostratin, through the activation of conventional and/or novel PKC isoforms, rapidly reduces cell surface expression of CD4 and CXCR4, but not CCR5, by inducing their internalization and degradation.
Design of Novel Bioisosteres of β-Diketo Acid Inhibitors of HIV-1 Integrase
Authors: Sechi Mario , Sannia Luciano , Carta Fabrizio , Palomba Michele , Dallocchio Roberto , Dessì Alessandro , Derudas Massimiliano , Zawahir Zahrah , Neamati Nouri
Published: March 2015

HIV-1 integrase (IN) is an attractive and validated target for the development of novel therapeutics against AIDS. Significant efforts have been devoted to the identification of IN inhibitors using various methods. In this context, through virtual screening of the NCI database and structure-based drug design strategies, we identified several pharmacophoric fragments and incorporated them on various aromatic or heteroaromatic rings. In addition, we designed and synthesized a series of 5-aryl(heteroaryl)-isoxazole-3-carboxylic acids as biological isosteric analogues of β-diketo acid containing inhibitors of HIV-1 IN and their derivatives. Further computational docking studies were performed to investigate the mode of interactions of the most active ligands with the IN active site. Results suggested that some of the tested compounds could be considered as lead compounds and suitable for further optimization.
Host Cell Targets in HCV Therapy: Novel Strategy or Proven Practice?
Authors: Klebl Bert M , Kurtenbach Alexander , Salassidis Kostas , Daub Henrik , Herget Thomas
Published: March 2015

The development of novel antiviral drugs against hepatitis C is a challenging and competitive area of research. Progress of this research has been hampered due to the quasispecies nature of the hepatitis C virus, the absence of cellular infection models and the lack of easily accessible and highly representative animal models. The current combination therapy consisting of interferon-α and ribavirin mainly acts by supporting host cell defence. These therapeutics are the prototypic representatives of indirect antiviral agents as they act on cellular targets. However, the therapy is not a cure, when considered from the long-term perspective, for almost half of the chronically infected patients. This draws attention to the urgent need for more efficient treatments. Novel anti-hepatitis C treatments under study are directed against a number of so-called direct antiviral targets such as polymerases and proteases, which are encoded by the virus. Although such direct antiviral approaches have proven to be successful in several viral indications, there is a risk of resistant viruses developing. In order to avoid resistance, the development of indirect antiviral compounds has to be intensified. These act on host cell targets either by boosting the immune response or by blocking the virus host cell interaction. A particularly interesting approach is the development of inhibitors that interfere with signal transduction, such as protein kinase inhibitors. The purpose of this review is to stress the importance of developing indirect antiviral agents that act on host cell targets. In doing so, a large source of potential targets and mechanisms can be exploited, thus increasing the likelihood of success. Ultimately, combination therapies consisting of drugs against direct and indirect viral targets will most probably provide the solution to fighting and eradicating hepatitis C virus in patients.
HIV-1 Subtype C Drug-Resistance Background among ARV-Naive Adults in Botswana
Authors: Bussmann Hermann , Novitsky Vladimir , Wester William , Peter Trevor , Masupu Kereng , Gabaitiri Lesego , Kim Soyeon , Gaseitsiwe Simane , Ndung'u Thumbi , Marlink Richard , Thior Ibou , Essex Max
Published: March 2015

Current HIV-1 antiretroviral (ARV) drug resistance knowledge is limited to HIV-1 subtype B (HIV-1B). We addressed whether unique genetic and phenotypic properties of HIV-1 subtype C (HIV-1C), southern Africa's most prevalent subtype, may foment earlier and/or distinct resistance mutations. Population-level HIV-1C genotypes were evaluated with respect to drug resistance prevalence before Botswana's public ARV treatment programme began. Viruses were genotyped from 11 representative districts of northern and southern Botswana, and consensus sequences from these 71 individuals and 51 previously reported sequences from HIV-positive blood donors were constructed. Phylogenetic analysis classified all 71 sequences but one, which exhibited pol gene mosaicism, as HIV-1C. The protease and reverse transcriptase coding region had no detectable known primary mutations associated with HIV-1B protease inhibitor (PI) drug resistance. Secondary mutations associated with PI drug resistance were found in all sequences. Several HIV-1C—specific polymorphic sites were found across the pol gene. Northern and southern Botswana viral sequences showed no significant differences from each other. Population genotyping shows that, without countrywide ARV treatment, HIV-1C—infected Batswana harbour virtually no primary mutations known to confer resistance to the three major HIV-1B ARV drug classes. Some secondary PI mutations and polymorphic sites in the protease enzyme necessitate continuous population monitoring, particularly after introduction of countrywide ARV treatment in Botswana. Although its PI resistance development rate and kinetics are not known, our data may suggest increased susceptibility and readiness of HIV-1C to develop resistance under drug pressure when the PI class of drugs is used.
Antiviral and Cytostatic Evaluation of the Novel 6-acyclic Chain Substituted Thymine Derivatives
Authors: Prekupec Svjetlana , Makuc Damjan , Plavec Janez , Kraljević Sandra , Kralj Marijeta , Pavelić Krešimir , Andrei Graciela , Snoeck Robert , Balzarini Jan , De Clercq Erik , Raić-Malić Silvana , Mintas Mladen
Published: March 2015

A series of the novel 5-methyl pyrimidine derivatives with an acyclic side chain at the C-6 position were synthesized using lithiation of a 2,4-dimethoxy-5,6-dimethyl pyrimidine and subsequent nucleophilic addition or substitution reactions of the organolithium intermediate thus obtained with acetaldehyde, epichlorhydrine, fluorinated ketones and fluorinated ester. The novel compounds were evaluated for their cytostatic and antiviral activities. Among all the compounds evaluated, two fluorinated acyclic pyrimidine derivatives showed the highest cytostatic activities. The compound containing a 2-hydroxy-3,3,3-trifluoro-1-propenyl side chain exhibited a pronounced effect against breast carcinoma (MCF-7, IC50=8.38 μg/ml), while the compound with a 2-fluoromethyl-2-acetoxypropyl chain exhibited moderate effect against cervical carcinoma (HeLa, IC50=19.73 μg/ml).
Cottontail Rabbit Papillomavirus (CRPV) Model System to Test Antiviral and Immunotherapeutic Strategies
Authors: Christensen Neil D
Published: March 2015

The cottontail rabbit papillomavirus (CRPV)/rabbit model has proven to be the most versatile pre-clinical model to test antiviral, immunopotentiating and immunotherapeutic strategies for papilloma-virus infections. We have utilized this model for many years and have recently observed significant improvements in the utility of the model. Improvements have included various techniques to infect rabbit skin sites with strains of wild-type and mutant CRPV DNA prepared using standard molecular biological procedures. A better understanding of the virus life cycle in vivo has been gained also from these studies such that we now have several defined strains of CRPV including i) antigenically diverse strains of CRPV, ii) mutant strains of CRPV with reduced growth rates, and iii) mutant strains of CRPV that demonstrate accelerated malignant progression rates. Collectively, these mutant genomes provide laboratories with a powerful pre-clinical model to assess a variety of antiviral therapies. Many of the treatments already tested in the CRPV/rabbit model have shown parallel efficacy against HPV infections in a clinical setting. Some of our recent experiences with the CRPV/rabbit model are outlined in this brief overview.
Inhibition of HIV-1 Replication by Oligonucleotide Analogues Directed to the Packaging Signal and Trans-Activating Response Region
Authors: Brown Douglas E , Arzumanov Andrey , Syed Sana , Gait Michael J , Lever Andrew M L
Published: March 2015

HIV possesses a remarkable capacity for mutational escape from therapeutics that target the viral proteins and enzymes. Inhibitory strategies aimed at highly conserved nucleic acid sequences within the genome are an attractive alternative. However, it has proven difficult to achieve an effective level of therapeutic at the appropriate site within the cell. Oligonucleotide delivery is a rapidly advancing field. We have investigated oligonucleotide analogues as steric-block therapeutics against two highly conserved regions of the HIV-1 genome. In the study we show that 2′O-methyl/locked nucleic acid oligonucleotides against the packaging signal and trans-activating response regions of HIV can inhibit replication of the virus.
Conversion of Viramidine to Ribavirin in Vivo by Adenosine Deaminase and its Inhibition by 2′-Deoxycoformycin
Authors: Wu Jim Zhen , Yeh Li-Tain , Lin Chin-Chung , Hong Zhi
Published: March 2015

Previously we reported that viramidine is a prodrug of ribavirin and that adenosine deami-nase catalyses viramidine deamination to ribavirin in vivo. This in vivo study explores this prodrug conversion in rats and inhibition by a potent adenosine deaminase inhibitor, 2′-deoxyco-formycin. We found that conversion of viramidine to ribavirin was viramidine dose-dependent in rat plasma. A single intravenous dose of 0.25 mg/kg 2′-deoxycoformycin suppressed orally administered viramidine conversion to ribavirin in plasma by 50%. The inhibition was 2′-deoxycoformycin dose-dependent and a single dose of 2 mg/kg decreased the ribavirin/viramidine area under the concentration—time curve between 0 h and 6 h ratio by 2.5-fold. These findings provide strong evidence that adenosine deaminase plays a major role in converting viramidine to ribavirin in vivo.
Anti-Influenza Virus Activities of 4-[(1,2-dihydro-2-oxo-3H-indol-3-ylidene)amino]-N-(4,6-dimethyl-2-pyrimidin-2-yl)benzenesulphonamide and its Derivatives
Authors: Selvam Periyasamy , Murugesh Narayanan , Chandramohan Markandavel , Sidwell Robert W , Wandersee Miles K , Smee Donald F
Published: March 2015

4-[(1,2-Dihydro-2-oxo-3H-indol-3-ylidene)amino]- N-(4,6-dimethyl-2-pyrimidinyl)-benzenesulphonamide (SPIII-5H) and related compounds were tested for antiviral activity against influenza A (H1N1, H3N2, and H5N1) and B viruses in Madin Darby canine kidney (MDCK) cell culture. Among the compounds tested, SPIII-5H and four derivatives (5-chloro [SPIII-5Cl], 5-bromo [SPIII-5Br], 5-methyl [SPIII-5Me] and N-acetyl [SPIII-NA]) showed similar antiviral potencies, with only the 5-fluoro (SPIII-5F) derivative being ineffective. Fifty percent effective concentration (EC50) values were determined in cytopathic effect (CPE) inhibition assays quantified by neutral red dye uptake. By this method, the active compounds were inhibitory to the H1N1 strain of influenza A at 2.7–5.2 µg/ml, to the H3N2 strain of influenza A at 13.8–26.0 µg/ml, to the H5N1 strain of influenza A at 3.1–6.3 µg/ml and to influenza B at 7.7–11.5 µg/ml. Confirmatory virus yield reduction studies against influenza A (H1N1) virus demonstrated antiviral activity (90% inhibition) at concentrations of 2–10 µg/ml. No cytotoxic effects were evident in actively growing uninfected cells or stationary monolayers at 100 µg/ml. Potencies of the compounds were similar to those of ribavirin, but much less than those of oseltamivir carboxylate against the various viruses. Time-of-addition studies indicated the compounds inhibited an early step in the virus replication cycle, probably virus adsorption/penetration, and no virucidal activity was evident. The basic molecule is amenable to diverse chemical modifications, which may improve water solubility and antiviral potency.
Evaluation of Immunomodulators, Interferons and Known in Vitro SARS-CoV Inhibitors for Inhibition of SARS-Cov Replication in BALB/c Mice
Authors: Barnard Dale L , Day Craig W , Bailey Kevin , Heiner Matthew , Montgomery Robert , Lauridsen Larry , Chan Paul KS , Sidwell Robert W
Published: March 2015

Compounds approved for therapeutic use and in vitro inhibitors of severe acute respiratory syndrome coronavirus (SARS-CoV) were evaluated for inhibition in the mouse SARS-CoV replication model. A hybrid interferon, interferon alpha (IFN-α) B/D, and a mismatched double-stranded (ds) RNA interferon (IFN) inducer, Ampligen® (poly I:poly C124), were the only compounds that potently inhibited virus titres in the lungs of infected mice as assessed by CPE titration assays. When mice were dosed intraperitoneally (i.p.) with IFN-α B/D once daily for 3 days beginning 4 h after virus exposure, SARS-CoV replication in the lungs of infected mice was reduced by 1 log10 at 10,000 and 32,000 IU; at the highest dose of 100,000 IU, virus lung titres were below detectable limits. Ampligen® used i.p. at 10 mg/kg 4 h prior to virus exposure also reduced virus lung titres to below detectable limits. Nelfinavir, β-D-N4-hydroxycytidine, calpain inhibitor VI, 3-deazaneplanocin A and Alferon® (human leukocyte IFN-α-n3) did not significantly reduce lung virus titres in mice. Anti-inflammatory agents, chloroquine, amodiaquin and pentoxifylline, were also inactive in vivo, suggesting that although they may be useful in ameliorating the hyperinflammatory response induced by the virus infection, they will not significantly reduce the replication of the virus, the inducer of inflammatory response. Thus, anti-inflammatory agents may only be useful in treating virus lung infections if used in combination with agents that inhibit virus replication. In summary, the data suggest that induction of IFN by mismatched dsRNA or actual treatment with exogenous IFN-α can inhibit SARS-CoV replication in the lungs of mice.
Structural Features and Antiviral Activity of Sulphated Fucans from the Brown Seaweed Cystoseira Indica
Authors: Mandal Pinaki , Mateu Cecilia Gabriela , Chattopadhyay Kausik , Pujol Carlos Alberto , Damonte Elsa Beatriz , Ray Bimalendu
Published: March 2015

Natural compounds offer interesting pharmacological perspectives for antiviral drug development. In this study, we have analysed sulphated-fucan-containing fractions isolated from the brown seaweed Cystoseira indica. The crude water extract (CiWE) and the main fraction (CiF3) obtained by anion exchange chromatography had potent antiviral activity against herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) without cytotoxicity for Vero cell cultures. Furthermore, they had no direct inactivating effect on virions in a virucidal assay, and lacked anticoagulant activity. The mode of action of these compounds could be mainly ascribed to an inhibitory effect on virus adsorption. Chemical, chromatographic and spectroscopic methods showed that the major polysaccharide had an apparent molecular mass of 35 kDa and contained a backbone of α-(1→3)-linked fucopyranosyl residues substituted at C-2 with fucopyranosyl and xylopyranosyl residues. This sulphated fucan, considered the active principle of the C. indica water extract, also contained variously linked xylose and galactose units and glucuronic acid residues. Sulphate groups, if present, are located mostly at C-4 of (1→3)-linked fucopyranosyl units, and appeared to be very important for the anti-herpetic activity of this polymer.
Pharmacokinetic Enhancement of the Hepatitis C Virus Protease Inhibitors VX-950 and SCH 503034 by Co-Dosing with Ritonavir
Authors: Kempf Dale J , Klein Cheri , Chen Hui-Ju , Klein Larry L , Yeung Clinton , Randolph John T , Lau Yau Y , Chovan Linda E , Guan Zhiwen , Hernandez Lisa , Turner Teresa M , Dandliker Peter J , Marsh Kennan C
Published: March 2015

Inhibitors of hepatitis C virus (HCV) protease have shown marked antiviral activity in short-term clinical studies in HCV-infected individuals. The interaction of the investigational HCV protease inhibitors VX-950 and SCH 503034 with ritonavir, a potent inhibitor of cytochrome P450 3A, was studied in vitro and in vivo. In rat and human liver microsomes, the metabolism of VX-950 and SCH 503034 was strongly inhibited by the presence of 4 µM ritonavir. Upon co-dosing either VX-950 or SCH 503034 with ritonavir in rats, plasma exposure of the HCV protease inhibitors was increased by >15-fold, and plasma concentrations 8 h after dosing were increased by >50-fold. A human pharmacokinetic model of VX-950 co-administered with low-dose ritonavir suggested that improved efficacy and/or dosing convenience may be feasible by pharmacokinetic enhancement with ritonavir.
Inosine Monophosphate Dehydrogenase as a Probe in Antiviral Drug Discovery
Authors: Nair Vasu , Shu Qingning
Published: March 2015

Inosine monophosphate (IMP) dehydrogenase (IMPDH) is a significant enzyme in the purine nucleotide biosynthetic pathway. IMPDH is viewed as an important biological target in the quest for drugs in the antiviral therapeutic area. This review article is focused on the chemistry and biology of IMPDH inhibitors and the use of IMPDH inhibition data as a probe in antiviral drug discovery. Examples of both inosine 5′ monophosphate and NAD+site-directed inhibitors are presented. Correlation of antiviral activities with IMPDH inhibition is discussed.
Novel 3-sulphonamido-quinazolin-4(3H)-One Derivatives: Microwave-Assisted Synthesis and Evaluation of Antiviral Activities against Respiratory and Biodefense Viruses
Authors: Selvam Periyasamy , Vijayalakshimi Paulchamy , Smee Donald F , Gowen Brian B , Julander Justin G , Day Craig W , Barnard Dale L
Published: March 2015

We designed and synthesized novel 2,3-disubstituted quinazolin-4(3 H)-ones by microwave technique and characterized them by spectral analysis. Synthesized compounds were screened for cytotoxicity and for antiviral activity against influenza A (H1N1, H3N2 and H5N1), severe acute respiratory syndrome corona, dengue, yellow fever, Venezuelan equine encephalitis (VEE), Rift Valley fever, and Tacaribe viruses in cell culture. A neutral red uptake assay was used to determine 50% virus-inhibitory concentrations (EC50) of test compounds and their 50% cytotoxicity concentration (CC50) in uninfected Madin-Darby canine kidney, Vero, and Vero 76 cells; selectivity indices (ratio of CC50 to EC50) were derived from the data. The compound 4-(6,8-dibromo-4-oxo-2-phenyl quinazolin-3(4 H)-yl)-N-(4,5-dimethyloxazol-2yl) benzenesulphonamide 15 inhibited the replication of avian influenza (H5N1) virus (EC50=8.4 µg/ml, CC50>100 µg/ml, SI>11.9) as did 4-(6-bromo-4oxo-2phenylquinazolin-3(4 H)-yl) benzene]sulphonamide 5 (EC50=3 µg/ml, CC50=32 µg/ml, SI=11). Compound 5 was also moderately active against VEE and Tacaribe viruses. The methodology described in this report is applicable for rapid synthesis of many compounds with potential antiviral properties.
Anti-Influenza Virus Activity of Propolis in Vitro and its Efficacy against Influenza Infection in Mice
Authors: Shimizu Tomomi , Hino Akane , Tsutsumi Atsuko , Park Yong Kun , Watanabe Wataru , Kurokawa Masahiko
Published: March 2015

Background:

Propolis has been used worldwide as a dietary supplement to maintain and improve human health. We examined whether ethanol extracts of Brazilian propolis exhibit antiviral activity against influenza virus in vitro and in vivo.

Methods:

Among 13 ethanol extracts screened in a plaque reduction assay, four showed anti-influenza virus activity. The anti-influenza efficacy of the four extracts was further examined in a murine influenza virus infection model. The mice were infected intranasally with influenza virus, and the four extracts were orally administered at 10 mg/kg three times daily for seven successive days after infection.

Results:

In this infection model, only one extract, AF-08, was significantly effective at 10 mg/kg in reducing the body weight loss of infected mice. The doses of 2 and 10 mg/kg were also effective in prolonging the survival times of infected mice significantly, but 0.4 mg/kg was not. The anti-influenza efficacy of AF-08 at 10 mg/kg was confirmed in a dose-dependent manner in mice. AF-08 at 10 mg/kg significantly reduced virus yields in the bronchoalveolar lavage fluids of lungs in infected mice as compared with the control. The reduction of virus yields by AF-08 at 10 mg/kg significantly corresponded to those induced by oseltamivir at 1 mg/kg twice daily from day 1 to day 4 after infection.

Conclusion:

The Brazilian propolis AF-08 was indicated to possess anti-influenza virus activity and to ameliorate influenza symptoms in mice. AF-08 may be a possible candidate for an anti-influenza dietary supplement for humans.
Human Immunodeficiency Virus Type 1 Entry and Chemokine Receptors: A New Therapeutic Target
Authors: Cammack Nick
Published: March 2015

After the identification of CD4 as the primary receptor for human immunodeficiency virus (HIV) type 1 entry into cells of the immune system, it soon became clear that CD4 alone was not sufficient to establish a productive infection. The search for the second receptors or co-receptors started over 10 years ago, and it was not until 1996 that the G protein-coupled 7-transmembrane receptors, CXCR4 and CCR5 were finally identified as the co-receptors for HIV-1 entry. The 7-transmembrane receptor family is a familiar therapeutic target for a number of diseases, and therefore these recent findings represent an exciting opportunity for new therapeutic approaches to the treatment of HIV-1 infection.
Isolation and Characterization of Novel Human Immunodeficiency Virus Integrase Inhibitors from Fungal Metabolites
Authors: Hazuda Daria , Blau Carol Uncapher , Felock Peter , Hastings Jeffrey , Pramanik Bernali , Wolfe Abigail , Bushman Frederic , Farnet Chris , Goetz Michael , Williams Marie , Silverman Keith , Lingham Russell , Singh Sheo
Published: March 2015

We have identified a series of novel inhibitors of human immunodeficiency virus type 1 (HIV-1) integrase by randomly screening natural product extracts using an in vitro biochemical assay designed to identify inhibitors of integrase-catalysed strand transfer. Equisetin recovered from the fungus Fusarium heterosporum and a novel enantiomeric homologue of equisetin from Phoma sp. were isolated as inhibitors of HIV-1 integrase in vitro. Two additional analogues, a novel decalin derivative, integric acid, and oteromycin were also discovered to be inhibitors of integrase. Equisetin and related compounds inhibit 3” end-processing and strand transfer as well as disintegration catalysed by either the full-length enzyme or the truncated integrase core domain (amino acids 50–212). These compounds also inhibit strand transfer reactions catalysed by stable complexes assembled in vitro and integration reactions catalysed by pre-integration complexes isolated from HIV-1-infected cells. The compounds described in this report are structurally novel and mechanistically distinct from many previously described inhibitors of HIV-1 integrase. These results demonstrate the utility of using an appropriately configured assay to identify compounds that are effective post-assembly and the potential of isolating novel integrase inhibitors from complex natural product extracts.
Inhibition of Human Immunodeficiency Virus Replication by RD6-Y664, a Novel Benzylhydroxylamine Derivative
Authors: Okamoto M , Fujiwara M , Kodama E , Yamamoto O , Shigeta S , Mitsuya H , Konno K , Yokota T , Baba M
Published: March 2015

We have examined novel benzylhydroxylamine derivatives for their inhibitory effects on the replication of human immunodeficiency virus (HIV) in cell cultures. Among the series, O-(2-chloro-6-fluo-robenzyl)hydroxylamine (RD6-Y664) was found to be the most potent inhibitor of HIV-1. The EC50 for HIV-1 strain IIIB was 1.6 μg/ml with a selectivity index greater than 38 in MT-4 cells. It also inhibited the replication of other HIV strains including a nonnucleoside reverse transcriptase (RT) inhibitor-resistant mutant, a nucleoside RT inhibitor-resistant mutant and HIV-2, in acutely infected cells. However, the compound did not affect HIV-1 production in chronically infected cells. A time-of-addition experiment and detection of proviral DNA synthesis suggested that RD6-Y664 targeted an early step of the viral replication cycle, presumably a process prior to reverse transcription. In fact, an assay for HIV-1 RT revealed that the compound did not suppress enzyme activity. Furthermore, RD6-Y664 did not show any inhibition of gp120–CD4 interaction, or binding of anti-CXCR4 antibody to CXCR4.
In vitro Sensitivity of Kaposi's Sarcoma Cells to Various Chemotherapeutic Agents Including Acyclic Nucleoside Phosphonates
Authors: Simonart Thierry , Andrei Graciela , Parent Dominique , Van Vooren Jean-Paul , De Clercq Erik , Snoeck Robert
Published: March 2015

The involvement of a viral agent in the pathogenesis of Kaposi's sarcoma (KS) points to antiviral agents as possible therapeutic and/or prophylactic options in the management of the disease. In the present study we investigated the antiproliferative effects of various chemotherapeutic agents, including acyclic nucleoside phosphonates, on the growth of KS-derived cells. Nested PCR amplification demonstrated that these cells do not contain human herpesvirus 8 (HHV-8) DNA sequences. The cytotoxicity of the chemotherapeutic compounds was less pronounced in KS cells than in human dermal microvascular endothelial cells, which are considered to be the normal counterpart of KS cells. Stimulation of KS cells with basic fibroblast growth factor (bFGF) and correction of the IC50 values by the doubling times revealed that the apparent chemotherapeutic resistance of KS cells could mainly be attributed to the long doubling times of these cells. bFGF-stimulated KS cells still exhibited no particular sensitivity to the acyclic nucleoside phosphonates whose activity extends to HHV-8, which is consistent with the absence of linear HHV-8 DNA synthesis in these cells. Our data suggest that neither anti-cancer agents nor antiviral agents such as the acyclic nucleoside phosphonates can discriminate efficiently between KS cells and normal endothelial cells.
Mouse Model of Respiratory Syncytial Virus Infection to Evaluate Antiviral Activity in Vivo
Authors: Sudo Kenji , Watanabe Wataru , Mori Shuichi , Konno Kenji , Shigeta Shiro , Yokota Tomoyuki
Published: March 2015

In this study, we have developed a practical mouse model for evaluating in vivo the antiviral activity of compounds against respiratory syncytial virus (RSV) infection. BALB/c mice are not particularly susceptible to RSV infection; however, infection rates were improved by pretreatment with the immunosuppressive agent cyclophosphamide (CYP). When mice were inoculated intranasally with RSV A2 strain, the pulmonary RSV titres of CYP-pretreated 10-week-old mice were higher than those of untreated 10-week-old and 28-week-old mice, peaking on days 4 and 5 post-infection. Sections of lung from RSV-infected mice pretreated with CYP, taken on day 4 postinoculation, showed widespread evidence of interstitial pneumonia and other significant pathological changes. We also confirmed that ribavirin, a representative antiviral agent, significantly reduced the pulmonary RSV titres of mice pretreated with CYP when administered intraperi-toneally.
Approaches and Strategies for the Treatment of Influenza Virus Infections
Authors: Colacino Joseph M , Staschke Kirk A , Laver W Graeme
Published: March 2015

Influenza A and B viruses belong to the Orthomyxoviridae family of viruses. These viruses are responsible for severe morbidity and significant excess mortality each year. Infection with influenza viruses usually leads to respiratory involvement and can result in pneumonia and secondary bacterial infections. Vaccine approaches to the prophy-laxis of influenza virus infections have been problematic owing to the ability of these viruses to undergo antigenic shift by exchanging genomic segments or by undergoing antigenic drift, consisting of point mutations in the haemagglutinin (HA) and neuraminidase (NA) genes as a result of an error-prone viral polymerase. Historically, antiviral approaches for the therapy of both influenza A and B viruses have been largely unsuccessful until the elucidation of the X-ray crystallographic structure of the viral NA, which has permitted structure-based drug design of inhibitors of this enzyme. In addition, recent advances in the elucidation of the structure and complex function of influenza HA have resulted in the discovery of a number of diverse compounds that target this viral protein. This review article will focus largely on newer antiviral agents including those that inhibit the influenza virus NA and HA. Other novel approaches that have entered clinical trials or been considered for their clinical utility will be mentioned.
Synthesis and Biological Activity of Novel 1H,3H-Thiazolo[3,4-a]Benzimidazoles: Non-nucleoside Human Immunodeficiency Virus Type 1 Reverse Transcriptase Inhibitors
Authors: Chimirri A , Grasso S , Monforte P , Rao A , Zappalà M , Monforte AM , Pannecouque C , Witvrouw M , Balzarini J , De Clercq E
Published: March 2015

Using a known human immunodeficiency virus type 1 (HIV-1) nonnucleoside reverse transcriptase inhibitor (NNRTI), 1-(2,6-difluorophenyl)-1 H,3 H-thiazolo[3,4- a]benzimidazole (TBZ NSC 625487) as the lead structure for drug design, a series of novel 1 H,3 H-thiazolo[3,4- a]benzimidazole derivatives substituted on the benzene-fused ring was prepared. Their in vitro anti-HIV-1 activity, as well as their inhibitory effects on the viral reverse transcriptase, were evaluated. The structure-activity relationships for these compounds are described and the results suggest that the apolar binding pocket of RT, into which the NNRTIs must fit, can accommodate only groups with a limited size and shape.
Novel 6-Azapyrimidine-2′-Deoxy-4′-Thionucleosides: Synthesis, Biological Evaluation and Conformational Analysis
Authors: Inguaggiato G , Hughes D , De Clercq E , Balzarini J , Simons C
Published: March 2015

We report the synthesis of novel 1-(2′-deoxy-4′-thio-β-D- erythro-pentofuranosyl)-(6-azapyrimidine) nucleosides and the subsequent preparation of a series of N3-substituted analogues. All the novel compounds were evaluated against a range of viruses, however they lacked any measurable activity. The lack of anti-herpetic activity may be a result of the parent nucleoside having poor affinity for herpes simplex virus type 1 thymidine kinase. Conformational analysis of the parent nucleoside showed a twist (3T2) sugar conformation commonly displayed by 2′-deoxy-4′-thionucleosides and the anti-human immunodeficiency virus type 1 agents zidovudine and 3′-fluoro-ddT.
Acyclovir Treatment of Skin Lesions Results in Immune Deviation in Mice Infected Cutaneously with Herpes Simplex Virus
Authors: Li ZhiHong , Sato Hitoshi , Fukuda Yoshiko , Kurokawa Masahiko , Kageyama Seiji , Kawana Takashi , Shiraki Kimiyasu
Published: March 2015

Clinical observations indicate that the antibody response to herpes simplex virus (HSV) in patients undergoing acyclovir treatment is reduced and, although the exact mechanism is not clear, some authors interpret it as immunosuppression. In order to clarify the mechanism, we cutaneously infected mice with HSV-1 and treated the resulting skin lesions with acyclovir. The immune response to infection and treatment in these mice was then analysed. Acyclovir treatment was given orally (20 mg/kg, three times daily), starting on day 0 (D0), 2 (D2) or 4 (D4) after infection and continuing until day 10. The serum antibody titre and the severity of skin lesions were significantly higher in the shortest treatment group (D4) than in the longer treatment groups (D0 and D2). In contrast, a skin test analysing delayed-type hypersensitivity (DTH) to HSV antigen showed that the D0 and D2 groups exhibited stronger DTH than the D4 group. Acyclovir treatment failed to cause a dissociation between DTH and antibody production in mice immunized with inactivated HSV antigen. However, acyclovir treatment in infected mice suppressed the development of skin lesions and resulted in a dissociation between DTH response and antibody production, indicating a typical immune deviation. This was supported by a change in the ratio of the isotype antibody IgG2a to IgG1. The treatment of skin lesions with acyclovir reduced the level of antibody response, as observed clinically. This indicates that the reduced antibody response in patients treated with acyclovir may be, at least in part, due to immune deviation and not immunosuppression.
Comparison of First- and Second-Generation Fixed-Bearing Total Ankle Arthroplasty Using a Modular Intramedullary Tibial Component
Authors: Lewis John S. , Green Cynthia L. , Adams Samuel B. , Easley Mark E. , DeOrio James K. , Nunley James A.
Published: March 2015

Background:

This series reviews the clinical and radiographic outcomes of patients who underwent total ankle replacement (TAR) using first- and second-generations of a modern fixed-bearing prosthesis utilizing a modular intramedullary stem.

Methods:

A consecutive series of first- and second-generation primary TARs with modular intramedullary stems were identified. Clinical outcome data were collected prospectively—including visual analog scale for pain, American Orthopaedic Foot & Ankle Society hindfoot-ankle, Short Musculoskeletal Function Assessment, and Short Form–36 scores. Preoperative coronal plane deformity and correction of deformity after TAR were assessed. Complications, subsequent procedures, and failure rates were compared. A total of 193 first- and 56 second-generation patients were identified with a mean follow-up of 3.7 and 2.1 years, respectively.

Results:

Clinical outcome data reflected significant improvements at 1 year postoperatively, and improvements were maintained at 2-year follow-up for each group. Improvement in visual analog scale scores were significantly better in the second-generation group at 1 year postoperatively, but this was not maintained at 2 years. Mean coronal tibiotalar angles for ankles with preoperative varus or valgus deformities were significantly improved. Correction was maintained until final follow-up, with no significant differences in deformity improvement between groups. The rate of reoperation at 2 years postoperatively on the affected foot or ankle subsequent to the index ankle replacement for patients in the first-generation group (18.5%) was higher compared to the second-generation group (15.9%), but the time until reoperation was not statistically significant ( P = .376). The implant failure rate was higher in the first-generation group (6.0%) compared to the second-generation group (2.6%) at 2 years postoperatively, but the time until failure was not significantly different ( P = .295).

Conclusion:

Patients who underwent TAR with a first- or second-generation fixed-bearing prosthesis with an intramedullary tibial component demonstrated significant improvements in all measures of pain and function with sustained improvements in coronal plane alignment. The second-generation prosthesis demonstrated slightly better improvements at 1 year and was associated with lower reoperation and implant failure rates.

Level of Evidence:

Level II, comparative series.
Forging a Strategic and Comprehensive Approach to Evaluation Within Public and Nonprofit Organizations
Authors: Newcomer Kathryn , Brass Clinton T.
Published: March 2015

The “performance movement” has been a subject of enthusiasm and frustration for evaluators. Performance measurement, data analytics, and program evaluation have been treated as different tasks, and those addressing them speak their own languages in their own circles. We suggest that situating performance measurement and data analytics within the broader field of evaluation would be theoretically parsimonious and fruitful. Scholars and practitioners of performance measurement and analytics may profitably use an evaluation mind-set and frame their tasks within the multidisciplinary field of evaluation practice. With this change in mind-set, we discuss some implications of viewing measurement, analytics, and other evaluation-related capacities within public organizations as part of an integrated, evaluation mission-support function. Working with other mission-support functions, evaluation capacity could be used by operating units to improve learning, strategy, and performance and better accomplish the mission. We outline steps that could be considered to help forge a more strategic and comprehensive approach to evaluation in public and nonprofit organizations.
Development and validation of a gaseous cavitation model for hydrodynamic lubrication
Authors: Song Yin , Gu Chun-wei , Ren Xiao
Published: March 2015

The prediction of cavitation in lubricants is of significance to the design and analysis of hydrodynamic bearings. In this paper, a numerical model for the gaseous cavitation in hydrodynamic lubrication problems is derived based on the cavitation mechanism and origination, which is different from the conventional cavitation conditions. The proposed gaseous cavitation model is then used to calculate the performance of several types of bearings, including a two-axially grooved plain journal bearing, a misaligned journal bearing and parallel thrust bearings with surface textures. The results are validated with experimental data and numerical results calculated by the Half-Sommerfeld, Reynolds, and JFO conditions. The advantage of this new model lies in its accuracy and its independence from the cavitation pressure, which is usually difficult to be accurately defined. Thus this gaseous cavitation model can be useful in the accurate prediction of the cavitation phenomenon and performance of hydrodynamic bearings under steady state.