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Biomedical subjects

M J Otto

Publications and source records attributed to M J Otto.

36 records · Page 2Linked to original sources
PubMed1988

Enantiomeric effects of homologues of disoxaril on the inhibitory activity against human rhinovirus-14.

X-ray crystallography studies of racemic 5-[7-[4-(4,5-dihydro-4-methyl-2-oxazolyl)phenoxy]heptyl]- 3-methylisoxazole bound to human rhinovirus-14 (HRV-14) indicate selective binding of the S isomer. This result correlates well with the 10-fold greater activity of the S isomer as compared to the R isomer. The enantiomeric effect on activity is explained by a hydrophobic interaction of the methyl group in the case of 2a, with a pocket formed by Leu106 and Ser107. The 4-ethyl, 4-propyl, and 4-butyloxazolinyl homologues were prepared and tested against HRV-14. All of these compounds exhibited a comparable stereochemical effect. In each case, the S isomer displayed greater levels of activity than the R. The results of energetic considerations of the oxazoline ring in an 8-A pocket bound to the HRV-14 binding site suggest that the twist angle between the oxazoline and phenyl rings resulting from hydrophobic interactions of the alkyl substituents could be one of the determining factors for biological activity.

Antiviral Agents↗
PubMed1987

Rubella--a case for immunising male adolescents.

An outbreak of rubella at a training institution for predominantly adolescent males is described. The cost and inconvenience of the outbreak furnish evidence that immunisation in its own right is worth while, and should not be seen only as a means of protecting susceptible females of child-bearing age.

Adolescent↗
PubMed1987

Inhibition of poliovirus uncoating by disoxaril (WIN 51711).

Disoxaril [WIN 51711, 5-[7-[4(4,5-dihydro-2-oxazolyl)phenoxy]heptyl]-3- methylisoxazole] inhibits the replication of polioviruses types 1 and 2 in HeLa cells by stabilizing the virus capsid, which results in the inhibition of the pH-dependent viral uncoating in endosomes and/or lysosomes. As shown by electron microscopy the virus entered into the cell by receptor-mediated endocytosis via coated pits and coated vesicles into endosomes irrespective of the presence or absence of the compound. Measurements of viral RNA synthesis showed that disoxaril completely inhibited the arrival of viral RNA in the cytoplasm for new RNA synthesis only when the inocula were preincubated with disoxaril for 15 min at 37 degrees at 0.3 microgram disoxaril/ml for poliovirus type 1 and 0.03 microgram disoxaril/ml for poliovirus type 2. Simultaneous addition of the compound and virus resulted in reduced inhibition of viral RNA synthesis. The inhibitory effect of the compound could be partially reversed up to 25 min p.i. if the compound was eluted from the cells.

Antiviral Agents↗
PubMed1987

Structure-activity studies of 5-[[4-(4,5-dihydro-2-oxazolyl) phenoxy]alkyl]-3-methylisoxazoles: inhibitors of picornavirus uncoating.

A series of substituted phenyl analogues of 5-[[4-(4,5-dihydro-2-oxazolyl) phenoxy]alkyl]-3-methylisoxazoles has been synthesized and evaluated in vitro against several human rhinovirus (HRV) serotypes. Substituents in the 2-position greatly enhanced activity when compared to the unsubstituted compound. Many of these compounds exhibited mean MICs (MIC) against five serotypes as low as 0.40 microM. The mean MIC correlated well (r = 0.83) with the MIC80 (the concentration that inhibited 80% of the serotypes tested). A quantitative structure-activity relationship study indicated a strong dependency of MIC on lipophilicity (log P) in combination with inductive effects (sigma m) and bulk factors (MW).

Antiviral Agents↗
PubMed1987

Recent developments in antiviral chemotherapy.

As can be seen from the preceding brief discussion, the prospects for new antiviral agents for the treatment of viral diseases ranging in severity from the common cold to AIDS appear promising. The latest advances in technologies such as crystallography, genetic engineering, and monoclonal antibodies are all being applied to the discovery of new ways to inhibit virus-specific processes. In addition, the development of diagnostic tests for viral diseases has proceeded at a rapid pace that should facilitate the proper use of the antivirals when they become available. The one lesson that has been learned in the antiviral field over the past decade is that virus-specific inhibitors do exist, and if an essential virus-specific process or protein can be identified, it is likely that a molecule can be found to inhibit or inactivate it.

Antiviral Agents↗
PubMed1986

The site of attachment in human rhinovirus 14 for antiviral agents that inhibit uncoating.

WIN 51711 and WIN 52084 are structurally related, antiviral compounds that inhibit the replication of rhino (common cold) viruses and related picornaviruses. They prevent the pH-mediated uncoating of the viral RNA. The compounds consist of a 3-methylisoxazole group that inserts itself into the hydrophobic interior of the VP1 beta-barrel, a connecting seven-membered aliphatic chain, and a 4-oxazolinylphenoxy group (OP) that covers the entrance to an ion channel in the floor of the "canyon." Viral disassembly may be inhibited by preventing the collapse of the VP1 hydrophobic pocket or by blocking the flow of ions into the virus interior.

Antiviral Agents↗
PubMed1986

Production of herpes simplex virus type 1 thymidine kinase in the presence of thymidine analogues.

Treatment of herpes simplex virus type 1 (HSV-1) infected Vero, BHK, BHKtk- and LMtk- cells with 5-iodo-5'-amino-2',5'-dideoxyuridine (AIdUrd) caused increased synthesis of ICP36 and an increase in HSV-1 thymidine kinase (tk) activity at late times of infection. The overproduced ICP36 was identified as the HSV-1 encoded tk protein by immunoprecipitation. Whereas the thymidine analogue 5'-amino-5'-deoxythymidine (AdThd) caused an increase in HSV-1 tk synthesis and activity in wild type Vero and BHK cells, 5-iodo-2'-deoxyuridine (IdUrd) caused a similar increase only in tk- cells (LMtk-, BHKtk-). In vivo and in vitro stabilization studies using a [35S]methionine pulse-chase experiment or heat inactivation studies with purified HSV-1 tk revealed that stabilization of tk by the analogues could not account for the extent of the observed increase. Since overproduction of tk is observed only at late times of infection, it is suggested that the presence of these thymidine analogues in either the viral DNA or the cellular nucleotide pools is responsible for the observed differential effects.

Animals↗
PubMed1986

Prevention of rhinovirus and poliovirus uncoating by WIN 51711, a new antiviral drug.

WIN 51711, a potent new antipicornavirus drug, has been shown to inhibit an early event in the replication cycle of human poliovirus type 2 and human rhinovirus type 2. WIN 51711 was not virucidal and had no measurable effect on the adsorption of [3H]uridine-labeled virions to cells. When virion penetration of the plasma membrane was determined through loss of sensitivity to neutralizing antisera, WIN 51711 had no effect on poliovirus penetration, but inhibited rhinovirus penetration by 40%. In the presence of WIN 51711, exposure of neutral red-encapsidated virus-infected cells to light at 3 h postinfection resulted in a 3-log reduction in the number of infectious centers, indicating that WIN 51711 maintained the viral RNA in the encapsidated state after penetrating the cell membrane. The inhibition of uncoating by WIN 51711 in the neutral red assay was found to be concentration dependent, with a concentration of 0.03 micrograms/ml resulting in a 90% inhibition of uncoating. Sucrose gradient sedimentation of lysates from whole cells infected with [3H]uridine-labeled poliovirus showed that poliovirions remained intact in the presence of WIN 51711, but were uncoated in the absence of drug. WIN 51711 also prevented thermal inactivation of poliovirus infectivity, indicating a direct stabilizing effect of this compound on virion capsid conformation.

Antiviral Agents↗
PubMed1985

[[(4,5-Dihydro-2-oxazolyl)phenoxy]alkyl]isoxazoles. Inhibitors of picornavirus uncoating.

A series of [[(4,5-dihydro-2-oxazolyl)phenoxy]alkyl]isoxazoles has been synthesized and evaluated as antipicornavirus agents. The effect of alkyl groups in the 4- and 5-position of the oxazoline ring, as well as the alkyl chain length, on antiviral activity was examined. Compound 14 was evaluated in vivo and was found to significantly reduce mortality at an oral dose of 4 mg/kg in mice infected intracerebrally with poliovirus-2. Compound 14 was also effective in preventing paralysis when administered intraperitoneally to mice infected subcutaneously with a lethal dose of ECHO-9 virus. On the basis of the results of these studies, compound 14 is a strong candidate for clinical evaluation as a systemic agent for the treatment of picornavirus infections.

Animals↗
PubMed1985

In vitro activity of WIN 51711, a new broad-spectrum antipicornavirus drug.

WIN 51711 (5-[7-[4-(4,5-dihydro-2-oxazolyl)phenoxy]heptyl]-3-methylisoxazole), a new antipicornavirus drug, is a potent inhibitor of human entero- and rhinoviruses at concentrations not inhibitory to HeLa cell growth. In plaque reduction assays, WIN 51711 reduced plaque formation by 9 enteroviruses and 33 rhinoviruses, with MICs of 0.004 to 0.17 and 0.004 to 6.2 micrograms/ml, respectively. Addition of WIN 51711 to infected cells at concentrations of 0.02 to 5.0 micrograms/ml reduced the yield of picornaviruses by 90%. Other RNA viruses (nonpicornaviruses) and DNA viruses were unaffected by the compound.

Antiviral Agents↗
PubMed1984

Physical and biological consequences of incorporation of antiviral agents into virus DNA.

The molecular basis for the antiviral activity is discussed for a variety of nucleoside compounds approved for clinical use in the U.S.A. (5-iodo-2'-deoxyuridine, 5-trifluoromethyl-2'-deoxyuridine, 9-beta-D-arabinofuranosyladenine, 9-(2-hydroxyethoxymethyl)guanine), or in clinical trial (E-5-(2-bromovinyl)-2'-deoxyuridine, 1-(2-deoxy-2-fluoro-beta-D-arabinosyl)-5-iodocytosine, 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide), or of specific interest to our laboratory (5-iodo-5'-amino-2',5'-dideoxyuridine, 5'-amino-5'-deoxythymidine). The consequence of incorporation of idoxuridine, the 5'-amino analog of thymidine or the 5'-amino analog of idoxuridine into the DNA of herpes simplex virus type 1 on transcription and translation is emphasized.

Acyclovir↗
PubMed1984

The relationship between the antiviral activity of 5'-amino-5'-deoxythymidine and its incorporation into herpes simplex virus type 1 DNA.

As part of our studies on the molecular basis for the antiherpes activity of 5'-AdThd (5'-amino-5'-deoxythymidine), a study of the HSV-1 DNA synthesized in infected Vero cells exposed to 5'-AdThd was undertaken. Unlike many other antiviral nucleoside analogs, 5'-AdThd did not inhibit HSV-1 DNA synthesis. Analysis of the DNA synthesized in the presence of [14C]5'-AdThd revealed that the analog was incorporated into the viral DNA in a dose-dependent manner and that the degree of incorporation correlated with the antiviral activity as measured by yield reduction assays. Analysis of the 5'-AdThd substituted DNA by centrifugation in neutral and alkaline sucrose gradients revealed no double-stranded breaks but an increase in single-stranded breaks, at very high concentrations of the analog. Analysis of HSV-1-specific RNAs revealed a shift from poly(A+) to poly(A-) RNA. The degree of this shift paralleled the substitution of 5'-AdThd for thymidine in the HSV-1 DNA.

DNA, Viral↗
PubMed1984

Effect of (E)-5-(2-bromovinyl)-2'-deoxyuridine on synthesis of herpes simplex virus type 1-specific polypeptides.

The antiherpesvirus agent (E)-5-(2-bromovinyl)-2'-deoxyuridine caused marked alterations in the synthesis and processing of several herpes simplex virus type 1 (HSV-1)-infected-cell polypeptides. Analogous to other thymidine analogs, there was a dose-dependent decrease in several beta and gamma polypeptides and an accumulation of HSV-1 thymidine kinase. In contrast to the action of other thymidine analogs, there were alterations in alpha polypeptides, including an increase in the synthesis and phosphorylation of infected-cell polypeptide 4b and a decrease in the synthesis of infected-cell polypeptide 27. The phosphorylation of several other HSV-1 phosphoproteins was mildly inhibited. (E)-5-(2-Bromovinyl)-2'-deoxyuridine inhibited the glycosylation of the major HSV-1 glycoproteins, and this activity appeared to be independent of the incorporation of the drug into the viral DNA. Thus, the alterations in HSV-1 polypeptide expression appear to be due to the presence of the drug in a low-molecular-weight form as well as its presence in the viral DNA. This suggests that this analog or a phosphorylated derivative might act as an inhibitor of an enzyme(s) responsible for posttranslational modification of polypeptides.

Animals↗
PubMed1982

Effects of nucleoside analogues on the expression of herpes simplex type 1-induced proteins.

Exposure of herpes simplex virus type 1 (HSV-1)-infected Vero cells to the nucleoside analogues 5-iodo-5'-amino-2',5'-dideoxyuridine (AIdUrd), 5-iodo-2'-deoxyuridine (IdUrd) or 5'-amino-2',5'-dideoxythymidine (5'-AdThd) resulted in altered expression of HSV-1-induced proteins. Infected cell proteins (ICPs) synthesized in the presence of the nucleoside analogues were compared by sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis to ICPs from non-drug-treated cells and it was found that there was no effect on HSV-1-induced alpha proteins but beta and gamma proteins were reduced as much as 60%. There were three exceptions: ICP 35 (Mr = 46,000) and ICP 39 (Mr = 36,000) were not reduced and ICP 36 (Mr = 42,000) was increased during drug treatment. Progeny virions were isolated from drug-treated infected Vero cells and were compared to progeny isolated from control cells with respect to their polypeptide make-up and for their ability to induce HSV-1 proteins in non-drug-treated Vero cells. The progeny virus from drug-treated cells exhibited altered protein patterns on SDS-polyacrylamide gels with respect to control HSV-1. The progeny virions from AIdUrd- or IdUrd- but not from 5'-AdThd-treated cells were defective in their abilities to induce proteins upon subsequent infection of non-drug-treated Vero cells. Two unusual phosphoproteins were detected; one with an apparent molecular weight of 30,000 was induced by progeny virus from AIdUrd-treated cells and another at approximately 69,000 was induced by progeny virus from 5'-AdThd-treated cells.

Animals↗
PubMed1980

the influence of the host cell on the inhibition of virus protein synthesis in cells double infected with vesicular stomatitis virus and mengovirus.

The ability of mengovirus to inhibit the synthesis of vesicular stomatitis virus (VSV) proteins and of VSV to inhibit the synthesis of mengovirus proteins during double infection in three different cell lines was investigated. Although cellular protein synthesis was inhibited after infection of cells by each virus, the ability of one virus to decrease translation of the mRNA species of the co-infecting virus varied with the cell type. Superinfection of mengovirus-infected L-929 cells by VSV resulted in essentially no inhibition in the synthesis of either mengovirus or VSV proteins. In HeLa cells and CHO cells the synthesis of both VSV and mengovirus proteins was inhibited under conditions of simultaneous or sequential infection. The inhibition of VSV protein synthesis after infection of HeLa cells by mengovirus was not a result of a modification or inactivation of virus mRNAs. When extracted from double infected cells, the VSV mRNAs manifested normal biological activity, as determined by their ability to stimulate the synthesis of VSV proteins in a micrococcal nuclease-treated cell-free system from L cells. The interference of non-interference of one virus by another in different cell lines was also measured by quantifying the number of infectious particles produced in each cell line. The results were similar to those reported above for protein synthesis inhibition. These experiments suggest that the interference of mengovirus with VSV mRNA translation in HeLa cells is not necessarily reflective of the mechanism by which mengovirus inhibits cellular protein synthesis. Also, the host cell appears to influence the extent or nature of the interference of one virus by the other.

Animals↗
PubMed1980

Enzymatic modifications of human fibroblast and leukocyte interferons.

The sensitivity of highly purified human fibroblast interferon and partially purified human leukocyte interferon to several proteolytic and glycolytic enzymes was determined with respect to antiviral activity, isoelectric point, molecular weight, and thermal stability. Leucine aminopeptidase altered the distribution of isoelectric points for both interferons but produced little change in molecular weights; this enzyme somewhat reduced the activity of only leukocyte interferon. Treatment of fibroblast interferon with carboxypeptidases A and B did not greatly decrease antiviral activity, but it did slightly reduce the molecular weight of the interferon and substantially altered the distribution of isoelectric point values; similar treatment of leukocyte interferon caused some loss in activity, especially of the 17,000-molecular-weight species. Both interferons were inactivated rapidly by treatment with the endoproteases trypsin, pepsin, bromelain, and subtilisin. Chymotrypsin shifted the isoelectric points of both interferons, but only leukocyte interferon was significantly inactivated. Treatment with neuraminidase and beta-galactosidase changed the isoelectric point distribution but did not affect the activity or thermal stability of either interferon; such a treatment reduced the molecular weight of fibroblast interferon and the size heterogeneity of leukocyte interferon. Treatment with neuraminidase and then leucine aminopeptidase greatly reduced the activity of both interferons, especially leukocyte interferon. The data indicate that biologically active forms of fibroblast and leukocyte interferons can be distinguished by their relative sensitivity to certain proteases.

Carboxypeptidases↗