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Biomedical subjects

M E Thouless

Publications and source records attributed to M E Thouless.

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

Isolation of two lapine rotaviruses: characterization of their subgroup, serotype and RNA electropherotypes.

Rotaviruses were detected by an ELISA test in stool specimens from diarrheic rabbits in two commercial rabbitries and cultured in MA 104 cells. Their identity was confirmed by electron microscopy and indirect immunofluorescence. They were found to belong to subgroup I by testing with monoclonal antibodies and to serotype 3 by neutralization with homologous and heterologous antisera. Although both viruses were neutralized by antiserum to human serotype 3 the ALA rabbit rotavirus was minimally neutralized by antiserum to the C11 rabbit rotavirus. Electrophoresis of viral RNA revealed 11 segments characteristic of rotavirus, however both rabbit rotaviruses had unusual electropherotypes. They differed from each other with greatly reduced mobility of the tenth segment in one virus and the eleventh segment in the other virus.

Animals↗
PubMed1986

Rotavirus-associated diarrhea in a commercial rabbitry.

An epizootic of diarrheal disease occurred in a commercial specific-pathogen-free rabbitry, and was characterized by sudden onset, rapid spread, and high morbidity and mortality among sucklings. Affected rabbits rapidly became dehydrated and most died within two days of the onset of diarrhea. Eight of these rabbits were necropsied. Five had blunted and fused small intestinal villi with attenuated villous enterocytes. A rotavirus was isolated from four rabbits, and five survivors of affected litters had strong antibody responses to rotavirus.

Animals↗
PubMed1986

Epidemiology of naturally occurring rotavirus infection in rabbits.

The epidemiology of naturally acquired rotavirus infection in commercial rabbitries was studied. Antibody titers to rotavirus were determined by an enzyme linked immunosorbent assay (ELISA). Studies of antibody levels over time within individual rabbit litters and in a colony of rabbits of different ages showed that transplacentally derived maternal antibodies had declined to low levels by about one month of age. More than half of the 88 rabbits 1 to 2 months of age had antibody titers of less than 1/100. All 98 rabbits over 2 months old had titers above 1/100 and 83 had titers over 1/1000. Rotavirus was detected in 25% of diarrheic feces and in 10% of normal feces.

Animals↗
PubMed1984

Age-related antibodies to rotavirus in New Zealand rabbits.

The prevalence of antibodies to rotavirus was determined in 199 New Zealand rabbits from a commercial rabbitry by an indirect immunofluorescent test. Virtually all rabbits less than 1 month old and greater than 2 months old had antibodies, whereas only 25% of rabbits 1 to 2 months old had antibodies.

Aging↗
PubMed1982

Serotyping and subgrouping of rotavirus strains by the ELISA test.

A method is described for the serotyping and subgrouping of rotaviruses by enzyme-linked immuno-sorbent assay (ELISA). For the isolates tested "blind" under code in parallel the serotyping results obtained by ELISA and serum neutralization of fluorescent focus formation were the same. After absorption of the typing antisera with purified heterotypic rotavirus, up to 128-fold differences in titres between isolates were observed in the ELISA test. The results of serotyping and subgrouping, by ELISA, of strains previously described and characterized by the authors' and other laboratories are also given. An attempt is made to correlate the serological findings with variations between virus strains based upon patterns of genome molecular weights as revealed by polyacrylamide gel electrophoresis. The application of this ELISA technique to epidemiological studies and vaccine research is discussed.

Animals↗
PubMed1981

The influence of divalent cations on the stability of human rotavirus.

The influence of divalent cations on the stability of human rotavirus was investigated using the indirect immunofluorescence (FA) technique in LLC-MK2 cells to titrate infectivity. Rotavirus infectivity was stabilized by calcium and strontium ions in solution but not by magnesium ions. Rotavirus isolates were found to be much less stable at 37 degrees C than at + 4 degrees C or 20 degrees. A study of virus morphology at intervals during the course of the experiment and treatment with the chelating agents EDTA and EGTA suggests that loss of infectivity coincides with the removal of the outer capsid layer and that calcium may be required to maintain virus integrity.

Animals↗
PubMed1980

Rotavirus serotypes by serum neutralisation.

A neutralisation test using cell culture and indirect immunofluorescence was applied to isolates of rotavirus from 55 patients with gastroenteritis, in order to determine serotypes. Frequent cross-reactions were observed, but subsequent statistical analysis confirmed the existence of at least three distinct serotypes. Some results, not sufficient for analysis, suggest that at least five serotypes probably exist. It is suggested that two or more viral polypeptides might be involved in neutralisation, one of which might be common to another serotype(s). This would explain the frequent cross-reactions detected by this neutralisation test. Evidence suggesting that some strains may be hybrids is also presented.

Animals↗
PubMed1979

Rotavirus polypeptides.

Rotavirus infected monkey kidney cells (LLC-MK2) have been labelled with 35S-methionine in the presence of actinomycin D. The cells have been lysed with SDS and the polypeptides separated by discontinuous polyacrylamide gel electrophoresis. Rotavirus polypeptides began to appear 4 to 5 h p.i.; incorporation was maximum at 8 h, but all the polypeptides were still being made 15 to 18 h p.i. Tissue culture adapted calf rotavirus particles were labelled with 35S-methionine and the polypeptides compared with cell associated rotavirus polypeptides. There were four inner coat, four outer coat and three non-structural polypeptides. Several of the outer coat polypeptides have altered mol. wt. on maturation. The polypeptides of rotavirus from seven species (human, pig, calf, lamb, mouse, foal and rabbit) have been compared and their mol. wt. calculated. The polypeptides fell into the same relative groupings for each virus, but there were variations in the mol. wt. of most comparable polypeptides. The polypeptides of tissue culture adapted and non-adapted calf rotavirus from the same original isolate varied only in one of the non-structural polypeptides.

Animals↗
PubMed1977

Serological relationships between rotaviruses from different species as studied by complement fixation and neutralization.

Human, piglet, mouse, foal, lamb, calf and rabbit rotaviruses all infected, but could not readily be subcultured in LLC MK2 cells. Cells infected with mouse and calf rotaviruses reacted by indirect immunofluorescence (FA) with convalescent serum from children, piglets, mice, foals, lambs, calves or rabbits, taken after rotavirus infection. Human, calf, piglet, mouse and foal rotaviruses reacted with human, calf, mouse, foal and lamb convalescent serum by complement fixation (CF). It was not possible to distinguish between different rotaviruses by CF or FA. Neutralization tests, however, detected species-specific rotavirus antigens. Any virus was neutralized by a much higher dilution of homologous species convalescent serum than by any heterologous serum. With the exception of the mouse virus there was very little cross reaction. However, in sera with a very high neutralizing titre for the homologous virus the titre was proportionately raised against heterologous virus. It is, therefore, now possible to type to species an unknown rotavirus by a neutralization test in LLC MK2 cells using convalescent serum from each species.

Animals↗
PubMed1977

Diagnosis of rotavirus infection by cell culture.

Rotaviruses were detected by electronmicroscopy in 35 of 84 specimens of faeces from infants with diarrhoea, and in 31 by fluorescent staining of tissue cultures infected with help of centrifugation. LLC-MK2 cells were found to be the most sensitive, although primary and secondary human-embryo-kidney and primary calf-kidney cells could also be used. A micromodification of the tissue-culture method provides a relatively simple technique for the diagnosis of rotavirus infection, for the titration of virus infectivity and for estimating neutralising antibodies in serum.

Animals↗
PubMed1976

The detection of virus DNA sequences in a herpes type 2 transformed hamster cell line (333-8-9).

Herpes simplex virus type 2 DNA labelled in vitro with 125I has been used as a probe to search for virus DNA sequences in the 333-8-9 line of transformed primary hamster cells and in clines derived from the line. Virus DNA sequences were present when the cells were examined initially but these sequences were lost on subsequent handling. No virus sequences were detected in clones derived from the line. It is suggested that the presence of virus DNA is an unstable characteristic of the cell line and that these sequences may be lost at cell division. The possibility that a small fragment of the genome remains cannot be excluded.

Base Sequence↗
PubMed1976

Serological relatedness of herpes simplex viruses. Type-specificity of antibody response.

The serological relatedness of forty-seven strains of type 1 and type 2 herpes simplex virus was investigated by reciprocal and non-reciprocal neutralization kinetics. Early rabbit antisera divided the virus strains into two distinct groups where confident indentification of virus type was possible. Hyperimmune mouse and rabbit antisera did not divide the two virus types into two distinct non-over-lapping groups. The extent of overlap varied with the particular attribute of the virus being studied. The virus types were best discriminated by their neutralizability by type 1 antisera and least well by their neutralizability by type 2 antisera. The results of reciprocal kinetic neutralization test with hyperimmune mouse antisera were analysed by multi-dimensional cluster analysis. Hyperimmune mouse or rabbit antisera could not be discriminated with respect to their immunogenic type by their absolute neutralization rate constants against either type 1 or type 2 virus, but could be distinguished on a group basis by their relative neutralizability against both virus types (antiserum specificity attribute); however, using this latter criterion, the type of immunogen could only be predicted in seven of the forty antisera under test. 'Early' mouse antisera could also be distinguished as groups by their absolute k-values against type 1 herpes virus. Thus, immunogenic identification, on other than a group basis, was unreliable. The specificity of a given serum was inversely related to its titre. There was a positive correlation between the specificity of a given virus strain and of its corresponding antiserum.

Animals↗