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Biomedical subjects

G M Allan

Publications and source records attributed to G M Allan.

At least 73 records · Page 4Linked to original sources
PubMed1988

An immunoperoxidase method of detecting respiratory syncytial virus antigens in paraffin sections of pneumonic bovine lung.

Using an avidin-biotin-peroxidase complex immunoperoxidase staining method, respiratory syncytial virus (RSV) antigen was demonstrated in glutaraldehyde-fixed, paraffin-processed lung sections from calves with induced RSV pneumonia. The virus also was detected in formalin-fixed, paraffin-processed lung sections from calves with naturally occurring RSV pneumonia. Specific immunoperoxidase staining was detected within the cytoplasm of epithelial cells and syncytia in small bronchi, bronchioli, and alveoli. Staining also was detected within exudates in airway lumina and in mononuclear and multinucleate cells within alveolar lumina. Optimal intensity of staining was achieved by proteolytic enzyme treatment of lung sections, using 0.1% pronase and overnight incubation in diluted primary antiserum. The distribution of antigen had a close correlation with presence of lesions. Antigen-staining patterns were similar in lung tissue from calves with naturally occurring and induced RSV disease.

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PubMed1985

The rapid detection of Aujeszky's disease virus in pigs by direct immunoperoxidase labelling.

Direct immunoperoxidase labelling on impression smears of brain and pharynx was compared with virus isolation and direct immunofluorescence for the detection of Aujeszky's disease virus in experimentally-infected pigs. Immunoperoxidase labelling was as sensitive as immunofluorescence and more sensitive than virus isolation for tissue that had been stored at room temperature (approximately 20 degrees C) for up to 144 h.

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PubMed1984

Epidemiology of rotavirus infection in broiler chickens: recognition of four serogroups.

In a longitudinal survey of 11 broiler flocks, rotavirus excretion was detected by direct electron microscopic examination of faeces in 10. In most of these flocks, rotavirus excretion was first detected during the third week of life. In some flocks, infection with 2 antigenically distinct serogroups of rotavirus was demonstrated. In a more detailed survey of a 34,000 bird broiler crop, rotavirus excretion was detected intermittently from 9-50 days. Infection with 4 different RNA electropherotypes of rotavirus occurred in waves with each wave of infection lasting about 1 week. Analysis of representatives of the 4 different electropherotypes by cross-immunofluorescence indicated that each electropherotype represented an antigenically distinct serogroup. Two of these serogroups were represented by the previously characterised Ch 1 and 132 chicken rotavirus isolates. The other 2 serogroups have not been previously recognised.

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PubMed1984

Coronavirus infection of the bovine respiratory tract.

Two viruses, morphologically resembling coronaviruses and antigenically indistinguishable from bovine enteric coronavirus, were isolated in bovine tracheal organ cultures from the lungs and trachea of young calves with respiratory disease. Intranasal and intratracheal inoculation of these viruses into neonatal calves resulted in a predominantly upper respiratory tract infection, which was associated with the development of mild respiratory symptoms.

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PubMed1984

Rapid diagnosis of Aujeszky's disease in pigs by immunofluorescence.

Direct immunofluorescence on impression smears of brain and pharynx was compared with virus isolation in cell culture for the diagnosis of Aujeszky's disease in experimentally and naturally infected pigs. Pharyngeal impression smears were more sensitive than virus isolation in two pigs killed 10 and 12 days after experimental infection. Both methods were of similar sensitivity in the detection of virus from field cases of disease. Smears of brain and pharynx were more sensitive than virus isolation for tissue which had been stored at room temperature (approximately 20 degrees C) for up to 48 hours. Some reduction in the amounts of virus recovered from tissues and the intensity of fluorescent staining occurred in these samples.

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PubMed1983

Experimental respiratory syncytial virus pneumonia in young calves: microbiologic and immunofluorescent findings.

Young calves were inoculated with respiratory syncytial virus (RSV) intranasally or by a combined intranasal and intratracheal route and were killed between postinoculation (initial) days (PID) 1 and 14. Viral antigens were detected by immunofluorescence in nasopharyngeal cells from calves killed between PID 2 and 10. Evidence of infection of the trachea and lungs with RSV was obtained by immunofluorescence and virus isolation in calves inoculated by the combined route, but not in calves inoculated intranasally. Within the lungs, RSV antigens were observed in epithelial cells of bronchioli and alveoli. The only virus detected in inoculated calves was RSV. With the exception of 1 calf, bacteria or mycoplasmas were not isolated from the lower respiratory tracts of inoculated calves. Antibody to RSV was not detected in calves killed up to PID 5, but 4 of 5 colostrum-deprived calves killed between PID 10 and 13 had antibodies to RSV. Preexisting, maternally derived antibody to RSV did not protect the calves from infection. Seemingly, the clinical signs of pneumonia and pathologic lesions observed in inoculated calves were caused by RSV infection.

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PubMed1981

Isolation from chickens of a rotavirus lacking the rotavirus group antigen.

A virus, designated 132 virus, was isolated from the faeces of chickens in chick embryo liver cell cultures. The morphology and morphogenesis of 132 virus were indistinguishable from that of rotaviruses. The nucleic acid of 132 virus had the nuclease resistance of double-stranded RNA, and was separated by polyacrylamide gel electrophoresis into 11 segments with mol. wt. ranging from 2.07 x 10(6) to 0.20 x 10(6). SPF chickens were susceptible to oral infection with 132 virus, which replicated in the villous epithelial cells of the small intestine. 132 virus was therefore a rotavirus by morphological, biochemical and biological criteria. However, by immunofluorescence it was not possible to demonstrate an antigenic relationship between 132 virus and known avian and mammalian rotaviruses, indicating that 132 virus does not possess the group antigen shared by all previously characterized rotaviruses. This finding has implications for the diagnosis of rotavirus infections by serological tests.

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PubMed1980

Polyacrylamide gel electrophoresis of avian rotavirus RNA.

The RNAs of 4 avian rotavirus isolates were analysed by polyacrylamide gel electrophoresis. One of these isolates was made from chickens, the other three were from turkeys. The RNAs were separated into 8 or 9 bands consisting of 11 segments, ranging in molecular weight from 0.24 X 10(6) to 2.09 X 10(6). In contrast to calf rotavirus, segments 10 and 11 of avian rotavirus RNA had very similar or identical electrophoretic mobilities. This may be a unique feature of avian rotavirus RNA. Co-electrophoresis experiments showed that the RNAs of 2 of the turkey isolates were electrophoretically identical. However, differences existed between these 2 isolates, the chicken isolate and the remaining turkey isolate with respect to segments 5, 6, the 7, 8, 9 complex and 10. Segment 5 of the chicken isolate was sometimes resolved into 2 components, and was further anomalous in that it was absent in some (analyses).

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PubMed1979

Isolation and cell culture propagation of rotaviruses from turkeys and chickens.

Rotaviruses were detected by electron microscopy in the faeces of turkey poults and broiler chickens with diarrhoea. Apparently symptomless infection was also observed in broilers. The avian rotaviruses could not be isolated in cell cultures by conventional techniques, but were adapted to serial growth in chick cell cultures following trypsin treatment of the virus and the cells. Immunofluorescence studies showed that the avian and mammalian rotaviruses are antigenically related. Antibodies to rotavirus were widespread in sera collected from turkeys, chickens and ducks.

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PubMed1978

Synthesis of coreless, probably defective virus particles in cell cultures infected with rotaviruses.

PK-15 cells infected with pig and lamb rotavirus strains which were not adapted to serial growth in cell cultures were examined by electron microscopy. A major difference between virus morphogenesis in the initial passage in PK-15 cells and in intestinal epithelial cells was the generation of large numbers of coreless virus particles in PK-15 cells. The numbers of coreless particles increased with increasing multiplicity of infection. Infectious virus was synthesized in PK-15 cells, but a variable decrease in infectivity titre occurred between 12 and 24 hours after infection. It is suggested that synthesis of defective interfering particles or an inhibitory substance such as interferon might account for this decrease.

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PubMed1978

Detection of antibody to bovine syncytial virus and respiratory syncytial virus in bovine fetal serum.

Batches of commercial fetal bovine serum, described by the suppliers as antibody-free, all contained antibody to bovine syncytial virus (BSV) when tested by indirect immunofluorescence. Antibody to bovine respiratory syncytial virus (RSV) was not detected in these sera. Twenty-four percent of individual fetal bovine sera contained antibody to BSV, and 14% contained antibody to RSV when tested by indirect immunofluorescence. BSV antibody titers in fetal sera from dams with high BSV antibody levels were variable but always higher than RSV antibody titers. Radial immunodiffusion studies with BSV-positive sera revealed the presence of immunoglobulin M (IgM), IgG, and IgA, but the quantity of these immunoglobulins was not directly related to the BSV antibody titers. The evidence suggests that the antibody present in fetal sera arose as the result of infection rather than from maternal transfer across the placenta.

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PubMed1977

Cell culture studies with a cytopathic bovine rotavirus.

The growth characteristics in MDBK cells of a calf rotavirus isolated in Northern Ireland are described. Of a range of cell cultures tested, the virus grew in secondary bovine kidney and MDBK cells, but consistently produced a CPE only in MDBK cells. The CPE consisted of cytoplasmic vacuolation, development of eosinophilic intracytoplasmic inclusions, and degeneration and detachment of cells from the monolayer. The onset of CPE was more rapid and its effects more severe in rolled cultures than stationary cultures. Immunofluorescent staining showed that the rotavirus was antigenically unrelated to avian and mammalian reoviruses. There was no significant difference in virus growth over the pH range 6.5 to 8.4.

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