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Biomedical subjects

D Chasey

Publications and source records attributed to D Chasey.

At least 37 records · Page 2Linked to original sources
PubMed1986

Definition of two new groups of atypical rotaviruses.

Comparative antigenic and nuclei acid analyses were carried out on two new atypical rotavirus isolates coming respectively from chickens (D/132) and pigs (E/DC-9). Indirect immunofluorescence showed that each virus carried different group antigens which were also distinct from those of previously described rotavirus groups. By genome profile analysis each virus had a pattern of genomic RNAs clearly distinct from those of the other rotavirus groups. Comparative terminal fingerprinting of corresponding genome segments from the two viruses showed large differences between them, indicating that all of their genomic RNAs had significant differences in sequence both from each other and from the three previously defined rotavirus groups. On the basis of these results, extension of the number of rotavirus groups from three to five is proposed, with isolates D/132 and E/DC-9 being the type members of groups D and E respectively.

Animals↗
PubMed1986

Replication of atypical ovine rotavirus in small intestine and cell culture.

Colostrum-deprived lambs experimentally infected with an atypical ovine rotavirus isolated from naturally scouring animals, and a naturally infected colostrum-deprived lamb, were examined by immunofluorescence and immunoperoxidase labelling, and electron microscopy. A hyperimmune serum to the virus was produced in a gnotobiotic lamb and used to demonstrate antigen in the villous epithelial cells of the small intestine from infected animals. Scanning and transmission electron microscopy of tissues from infected animals revealed giant multinucleate syncytia composed of fused epithelial cells. Infected cells contained intracytoplasmic virus particles which resembled group A rotaviruses in morphology and morphogenesis. Small numbers of infected cells in MA104 cultures inoculated with ovine atypical rotavirus could be detected by immunofluorescence but virus growth could not be maintained by passage. Virus particles were seen by thin-section electron microscopy but their morphology and morphogenesis were abnormal; they were each composed of a single electron-dense shell, with no core, and were associated with envelopes of smooth membrane rather than rough endoplasmic reticulum.

Animals↗
PubMed1984

Evaluation of ELISA and electron microscopy for the detection of coronavirus and rotavirus in bovine faeces.

Enzyme-linked immunosorbent assay (ELISA) was compared with electron microscopy in the examination of faeces from experimental calves and showed 100 per cent agreement in the detection of 19 bovine coronavirus and 15 bovine rotavirus electron microscope positive samples. In a limited field survey of calf diarrhoea 75 selected faeces were examined independently by ELISA and electron microscopy and the agreement between the two tests was 95 per cent for coronavirus and 84 per cent for rotavirus. A further comparison was made with 74 samples submitted for routine diagnosis and this yielded agreements of 82 per cent (coronavirus) and 89 per cent (rotavirus). Factors contributing to discrepant results were examined and the relative advantages and disadvantages of the two tests for routine detection of these enteric viruses are discussed.

Animals↗
PubMed1984

Detection of immunoperoxidase labelled mycoplasmas in cell culture by light microscopy and electronmicroscopy.

A McCoy cell line persistently infected with Mycoplasma orale was examined by light microscopy and electronmicroscopy after specific labelling with a direct immunoperoxidase conjugate. Mycoplasmas were readily detected in monolayer cultures in bright-field conditions and these were related to labelled organisms observed by electronmicroscopy in thin sections of similar cells. The specificity of the conjugate for M. orale was demonstrated by blocking with unconjugated antiserum, and by its inability to detect M. bovirhinis. Non-specific background labelling was consistently absent.

Antibodies, Bacterial↗
PubMed1983

Isolation of a syncytium-forming virus from a goat with polyarthritis.

Virus particles, morphologically indistinguishable from maedi-visna virus or caprine arthritis-encephalitis virus, were detected in tissue explant cultures prepared post mortem from a goat with joint, lung and kidney lesions similar to those associated with the caprine arthritis-encephalitis complex. Serum from this goat and others in its herd of origin gave positive reactions in an agar gel immunodiffusion test for maedi-visna virus antibodies.

Animals↗
PubMed1983

Electron microscopy of tubular assemblies associated with naturally occurring bovine rotavirus.

Three types of regularly constructed assembly have been observed by electron microscopy of rotavirus-containing faeces from naturally infected cattle. Two of the structures, designated rotatube 1 and rotatube 2 respectively, are tubular in nature, and the third, designated rotatube 3, takes the form of large relatively disorganized sheets of material exhibiting, in some areas, tubular characteristics. Rotatube 1 is a 'wide' tube of approximately 80 nm diameter, the wall of which is composed of a surface lattice of hexagonally arranged subunits. Rotatube 2 is a 'narrow' tube, half the diameter of the wide tube, and does not exhibit a strictly hexagonal surface lattice. The sheets of rotatube 3 material are composed of subunits arranged on an hexagonal lattice identical with that of rotatube 1. The dimensions and general structural characteristics of the three types of assembly indicate that they are composed of rotavirus capsid protein.

Animals↗
PubMed1983

Experimental infectious bovine rhinotracheitis: comparison of four antigen detection methods.

The duration of detectable viral antigen in nasal secretions was studied by four methods in calves experimentally infected with infectious bovine rhinotracheitis. Virus isolation in cell culture was the most sensitive and was successful for up to 11 days after inoculation. Three direct rapid antigen detection systems (immunofluorescence, immunoperoxidase and enzyme-linked immunosorbent assay [ELISA]) were all successful during the pyrexic phase, but less useful in the later stages of the disease. Virus isolation and ELISA remained positive in strongly positive samples stored for a week at room temperature.

Animals↗
PubMed1982

An investigation into the susceptibility of cattle to bovine leukosis virus following inoculation by various routes.

The effect of different routes of inoculation on the incubation period, as indicated by the detection of antibody and by the detection of bovine leukosis virus (BLV) in lymphocytes, were compared. None of the 12-month-old steers exposed to BLV by the oral route developed BLV infection. Intratracheal, subcutaneous and intradermal inoculations were found to be particularly effective in establishing BLV infection, which was detected three to four weeks after inoculation. In the majority of animals, serum antibody and virus were detected at the same time. One out of four in-oestrus heifers inoculated via the uterus with mixtures of BLV infected lymphocytes and semen became infected. It appears that there is an inhibitory factor in fresh semen that prevents BLV infection from becoming established. Viral antigen was detected earlier in BLV infected lymphocytes using the cocultivation method than by electron microscopy to demonstrate BLV particles in mitogen stimulated lymphocytes.

Animals↗
PubMed1981

Virus-like particles in bovine turbinate cells infected with bovine virus diarrhoea/mucosal disease virus.

Thin sections of bovine turbinate cells grown in culture and infected with the NADL strain of bovine virus diarrhoea/mucosal disease virus have been examined by electron microscopy. Infected cells exhibited ultrastructural modification of the rough endoplasmic reticulum and associated with this small numbers of virus-like particles were observed. Advanced stages of cytopathic effect were illustrated by cells showing a marked increase in electron-density. These features were not observed in uninfected control cultures.

Animals↗
PubMed1981

Investigation of the possible role of the tuberculin intradermal test in the spread of enzootic bovine leukosis.

The single intradermal comparative test was used with both avian and bovine tuberculin. Three cattle infected with bovine leukosis virus (BLV) were used as a source of infection. BLV-positive and susceptible animals were tuberculin tested alternately. Fifteen susceptible calves and 15 susceptible sheep were tested. A further three valves and three sheep were used as controls; the needles of the tuberculin syringes were deliberately contaminated with blood from the BLV-infected cattle, before being used in the test. Whereas all three calves and the three sheep inoculated intradermally with contaminated needles developed BLV infections, all of the other 30 animals have remained serologically negative to BLV for 10 months. Transmission of BLV with needles contaminated with BLV-infected blood was prevented by wiping the needles with absorbent cotton wool.

Animals↗