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Biomedical subjects

K F Shortridge

Publications and source records attributed to K F Shortridge.

At least 109 records · Page 6Linked to original sources
PubMed1977

Persistence of Hong Kong influenza virus variants in pigs.

The A/Hong Kong/1/68 (H3N2) influenza virus which has not been isolated from man for several years, was recently isolated from pigs in Hong Kong. Influenza viruses similar to A/Victoria/3/75, which are currently circulating in man, were also isolated from pigs. Both above-mentioned viruses could be transmitted readily from pig to pig in experimental studies. The isolation of influenza viruses similar to A/Hong Kong/68 from pigs in 1976 suggests that pigs may serve as a potential reservoir for future human pandemics as well as a possible source of genetic information for recombination between human and porcine strains of influenza virus.

Animals↗
PubMed1977

Salmonella in pig carcasses for human consumption in Hong Kong: a study on the mode of contamination.

A very high proportion (75%) of the pigs slaughtered in Hong Kong were found to be infected with salmonellas. Seven serotypes including Salmonella choleraesuis were isolated but the majority (91%) were S. anatum and S. derby. These serotypes, especially S. anatum and S. derby, had been isolated frequently from clinical cases, symptomless carries and in this study from abattoir workers, suggesting that the pig was a significant source for human salmonella infection. The majority of pigs slaughtered are imported and the high level of apparent infection was thought to be due to cross-infection during transport of the pigs under stress. S. anatum and S. derby were also isolated from pigs at 60 degreesC for 5 min caused no great reduction in the degree of superficial contamination. The two predominant serotypes were isolated from the tank and from drain swabs, and also from the latter held under scalding tank conditions. Thus, in spite of the introduction of hygienic slaughter under modernized conditions employing an automatic conveyance system 55% of the carcases were superficially contaminated after dressing before despatch to customers. Control of infection before slaughtering would appear crucial and a more thorough rinsing or washing of the dressed carcasses desirable.

Abattoirs↗
PubMed1977

Rubella virus serology:detection of residual lipoprotein inhibitors of haemagglutination using sensitive indicator arboviruses.

Immune and non-immune rubella sera were examined in the haemagglutination inhibition (HAI) test to evaluate the removal of lipoprotein non-specific inhibitors (NSI) of haemagglutination after kaolin and manganous chloride/heparin treatments. The sera were titrated fresh or after lipoprotein deterioration brought about by ageing the samples at 4 degrees C for various periods of time and by freezing at -20 degrees C with subsequent thawing. Deterioration was seen as altered electrophoretic mobility while the lipoproteins in treated sera were detected by indicator arboviruses whose haemagglutination is known to be strongly inhibited by the native macromolecules. After both treatments, notably manganous chloride/heparin, residual NSI activity was detected in deteriorated samples, particularly with group B arboviruses such as Japanese encephalitis and west Nile viruses but generally less so or not at all with the group A arboviruses employed. Absolutely fresh sera are considered highly desirable for rubella virus HAI assay, and it is suggested that the efficiency of lipoprotein NSI removal regardless of treatment protocol could be monitored in parallel HAI tests using carefully chosen indicator arboviruses. This could be done in conjunction with density gradient centrifugation of doubtful sera should ultracentrifuging facilities be available. The suitability of the monitoring procedure would be dependent to some extent on whether certain arboviruses are known to be endemic in a particular area.

Antibodies, Viral↗
PubMed1977

Isolation and characterization of influenza A viruses from avian species in Hong Kong.

Surveillance of apparently healthy ducks, chickens, and geese at a poultry dressing plant in Hong Kong yielded 51 haemagglutinating viruses 25 of which were influenza A viruses. Of these, 24 were subtyped into 13 combinations based on haemagglutinin and neuraminidase surface antigens. Of the 13 different influenza A viruses isolated, 7 possessed combinations of haemagglutinin and neuraminidase subunits that have not been reported previously-i.e., Hav2N1, Hav2Nav5, Hav4N2, Hav7N2, Hav7Nav1, Hav7Nav3, and Hav7Nav6. Four of the isolates were non-avid: they were not neutralized by antisera to any of the reference subtypes of influenza A viruses, yet antisera to each isolate inhibited both that virus and a known reference strain. The large number of combinations of haemagglutinin and neuraminidase and the isolation of two different influenza A viruses from one duck suggests that recombination may be occurring in nature.

Animals↗
PubMed1976

Diffusion coefficient and molecular weight of type 5 adenovirus by photon-correlation spectroscopy.

The technique of photon-correlation spectroscopy (intensity fluctuation spectroscopy) is applied to light scatter from type 5 adenovirus undergoing Brownian motion in solution and the translation diffusion coefficient (D20,w) measured to be 0,367 +/- 0.003 Fick units. Using Svedberg's equation with previously determined parameters, a molecular weight of 165 - 10(6) +/- 5 - 10(6) is obtained.

Adenoviridae↗
PubMed1976

Comparison of the activities in inhibition of haemagglutination by different togaviruses for human serum lipoproteins and their constituents.

The 3 major lipoprotein fractions of human serum were investigated for their ability to inhibit the haemagglutination of 24 different togaviruses including rubella virus and arboviruses from 5 antigenic groups. All viruses were inhibited by the 3 fractions and this was most evident with low and very low density lipoproteins; inhibitory activity appeared to be associated with the lipid part of the lipoproteins. When artificial dispersions of the lipids cholesterol, cholesteryl ester and triglyceride were emulsified with egg lecithin three categories of inhibitory activity were observed which were independent of virus antigenic grouping -- category 1, no activity; category 2, activity confined to cholesterol and category 3, activity for cholesterol and to a lesser extent the other lipids.

Arboviruses↗
PubMed1976

Removal of non-specific serum inhibitors of haemagglutination of rubella virus by treatment with dodecylamine-gel.

The suitability of using dodecylamine-gel for removing the serum non-antibody-like inhibitors of haemagglutination by rubella was studied. Compared with kaolin and MnCl2/heparin treatment this new procedure appears to have a higher specificity since it removes the non-antibody-like inhibitors from serum without affecting the immunoglobulin level significantly. The potential application of this procedure in routine serological analysis for rubella virus infection is discussed.

Amines↗
PubMed1976

A note on the use of trypsinized human group O erythrocytes in arbovirus titrations.

Twenty-two different arbovirus antigens derived from five antigenic groups were examined for their ability to agglutinate normal and trypsinized human group O erythrocytes. Trypsinization rendered the cells susceptible to agglutination by 18 viruses,chiefly in the pH 5.85 to 6.2 range, yielding hemagglutinin titers comparable with those obtained with gander cells at their optimal pH.

ABO Blood-Group System↗