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Biomedical subjects

W M Hammon

Publications and source records attributed to W M Hammon.

At least 19 recordsLinked to original sources
PubMed1975

"Hippie" hepatitis: an epidemiologic investigation conducted within a population of "street-people".

An epidemiologic investigation of viral hepatitis among "street-people" was conducted in Pittsburgh, PA in 1971. Among 146 individuals, 100 admitted to parenteral drug use and 73 (50%) had evidence of acute viral hepatitis. Counterelectrophoresis (CEP) and complement-fixation (CF) were used to test for type B antigen (HBS AG). Seventeen individuals (22%) had detectable HBSAG; 13 of these were clinically ill and admitted to drug use, Type B antibody (anti-HBS) was tested for by CEP and radioimmunoprecipitation (RIP). Thirty-five persons (29%), 15 of whom admitted to drug use and were ill, had detectable antibody by RIP; none had detectable antibody by CEP. None of those tested had both HBSAB and anti-HBS Evidence to support the hypothesis of sexual transmission of type B virus was found. Use of prophylactic gamma globulin in street-people populations is recommended.

Adolescent↗
PubMed1974

Cross-protection between group B arboviruses: resistance in mice to Japanese B encephalitis and St. Louis encephalitis viruses induced by Dengue virus immunization.

Albino Swiss mice, immunized with any of several types and strains of dengue viruses, were afforded substantial protection against peripheral Japanese B encephalitis or St. Louis encephalitis virus challenge. Dengue-2 (New Guinea "C")-immunized mice showed, 10 and 20 weeks after immunization, undiminished resistance with concomitant cyclophosphamide treatment and virus challenge. Examination of the effects of immunization on Japanese B encephalitis virus pathogenesis, after virus challenge with concomitant cyclophosphamide treatment, indicated that protection was associated with decreased viremia and virtually no virus replication in the brain as compared with controls. These effects could be demonstrated before detection of any neutralizing antibody to the challenge virus. From the applied aspect, the data support the hypothesis, based on epidemiological evidence and experiments in hamsters, that prior exposure of man to dengue viruses can confer some degree of protection against Japanese B encephalitis or St. Louis encephalitis disease.

Animals↗
PubMed1973

Viral encephalitis.

Explore the source record for details and available documents.

Arbovirus Infections↗
PubMed1973

Semi-commercial-scale production of Japanese B encephalitis virus vaccines from tissue culture.

This study was undertaken to modify and develop procedures for tissue culture-inactivated Japanese B encephalitis (JBE) virus vaccine production in large quantities. Various types of glass bottles were tried and, considering many advantages, long cylindrical roller (CR) bottles were selected. Several variables were investigated including number and volume of trypsinized cells to be seeded, volume of growth medium required for optimum cell growth, amount of calf serum, and volume of harvest medium for a high-titer virus yield. A good confluent cell sheet in CR bottles was obtained within a week by increasing the calf serum from 4 to 10% and when such tissue in a CR bottle was inoculated with 45,000 viral mean tissue culture infective doses directly into the medium, the cytopathological effects (CPE) appeared on day 5. High-titer virus yields were obtained when the harvests were made at 4(+) CPE using medium 199 with 2% human albumin at pH 8.3 to 8.5. No appreciable gain in titer was found from such harvests by blending to release intracellular virions. The production methods finally adopted gave consistently good results, and several inactivated JBE virus vaccine lots with minimum immunizing doses, ranging from 0.005 to 0.017 ml, were prepared using a large number of CR bottles in a simulated commercial-scale production system.

Animals↗
PubMed1972

Effect of urea on the hemagglutinating and complement-fixing antigens of type 2 Dengue virus.

Sephadex G-200 filtration was used for fractionating dengue type 2 (DEN-2)-infected suckling mouse brain (SMB) supernatant fluids. The high-molecular-weight fraction, which was eluted in the void volume, showed no increase in type specificity when tested against immune ascitic fluid to the four prototype dengue viruses. A void-volume fraction obtained after the infected SMB supernatant fluids were treated with urea displayed significant increases in complement fixation (CF) type specificity. Immune ascitic fluid prepared against the more typespecific DEN-2 antigen demonstrated neutralizing ability and greater CF type specificity. When DEN-2 sucrose-acetone-extracted hemagglutinating (HA) antigens were treated with 6 m urea at 37 C for various time intervals, all HA antigen was destroyed in 15 min. Urea treatment of infected SMB supernatant fluids indicated that the CF antigens were more stable to the effect of urea than were the HA antigens. After urea treatment of the SMB supernatant fluids, the CF type specificity increased as the hemagglutination inhibition titer decreased.

Animals↗