Search PubMed⌕ Search

Biomedical subjects

M F Stewart

Publications and source records attributed to M F Stewart.

26 records · Page 2Linked to original sources
PubMed1984

Interaction between feline leukaemia virus subgroups in the pathogenesis of erythroid hypoplasia.

The interaction of feline leukaemia virus (FeLV) of subgroups A and C in the pathogenesis of erythroid hypoplasia in cats was studied. Weanling kittens infected with FeLV-A became permanently viraemic but remained haematologically normal over a period of 36 weeks. Similar kittens inoculated with FeLV-C, which produces erythroid hypoplasia when administered to newborn kittens, neither became viraemic nor developed the disease. However, weanling kittens inoculated with a mixture of FeLV-A and C became viraemic, first with FeLV-A and then additionally with FeLV-C, and the emergence of FeLV-C into the blood coincided with the advent of erythroid hypoplasia. When FeLV-C was inoculated into five older cats which had been viraemic with FeLV-A for several months previously, it appeared in the plasma of three of the cats and erythroid hypoplasia was diagnosed in two of these, 16-20 weeks after infection with FeLV-C. These results show that FeLV-A enhances the growth of FeLV-C in cats and overcomes their age-related resistance to FeLV-C. Also, the appearance of FeLV-C in the plasma of cats viraemic with FeLV-A indicates that erythroid hypoplasia will subsequently occur rapidly. These findings are relevant to the origin of FeLV-C isolates and their occurrence in nature.

Anemia, Aplastic↗
PubMed1982

Detection of transient and persistent feline leukaemia virus infections.

A study was made of cats persistently or transiently viraemic with feline leukaemia virus (FeLV) following experimental oronasal infection. Cats of two ages were exposed to the virus. One group was infected when eight weeks old in the expectation that most of the cats would become persistently viraemic, and the second group when 16 weeks old, so that some would show signs of a transient infection and then recover. The periods following infection when virus was detectable in the blood and in the oropharynx were determined for each group. Three methods for detecting viraemia were compared: virus isolation, immunofluorescence on blood smears and an enzyme-linked immunosorbent assay (ELISA). There was good overall agreement among the three tests in detecting virus-positive cats. Virus was found sooner after infection by virus isolation than by the other methods, and virus appeared in the blood slightly sooner in cats which developed persistent viraemia than in transiently viraemic cats. Infectious FeLV was isolated from the oropharynx of all of the persistently viraemic cats, in most cases simultaneously with virus in the plasma. Virus was also isolated from the mouth of most transiently viraemic cats. Under field conditions such transient excretion of virus lasting only a few days would rarely be detected in a single sampling. This might explain how FeLV is maintained in free range urban cats in the absence of a large number of cats with persistent active FeLV infection. For routine diagnosis, immunofluorescence would appear to offer the best chance of differentiating transient and persistent infections by FeLV.

Age Factors↗
PubMed1981

Conditional probabilities and the grid test for schizophrenic thought disorder.

The grid test for schizophrenic thought disorder was administered to a sample of 149 psychiatric patients. This sample was drawn from a population with a known base rate of schizophrenia and an estimated base rate of thought disorder, thus allowing for the calculation of population specific cutting scores for the grid test. The grid test, using these data along with others from previous grid test studies, was then analysed for diagnostic efficiency using conditional probability formulae. The conclusion reached is that the grid test for schizophrenic thought disorder is unsatisfactory as a diagnostic instrument.

Diagnosis, Differential↗