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Biomedical subjects

J R Gorham

Publications and source records attributed to J R Gorham.

At least 109 records · Page 6Linked to original sources

Internal parasites of Washington cattle.

The occurrence of internal parasites in Washinton cattle was estimated. During the survey period in 1972 and 1973, more than 3,700 fecal samples from 29 herds and 4 feedlots, and viscera from 55 cattle were examined. The percentage of fecal samples with parasite eggs or oocysts from herds was as follows: oocysts, 77%; "strongyline" eggs, 44%; Nematodirus eggs, 3%; Moniezia eggs, 3%; Fasciola eggs, 2%; Trichuris eggs, 2%; and Dictyocaulus larvae, 1%. The fecal samples from feedlots contained principally strongyline eggs which varied markedly in numbers among groups of cattle in the lots. The predominant parasite in viscera was Ostertagia spp, which was recovered from all of the cattle examined. Other parasites identified in the survey were found less frequently in these examinations. Cattle in dairy and beef operations utilizing irrigated pastures were particularly prone to Fasciola infections, and more strongyline eggs were observed there than in fecal samples from other management systems. Seasonal fluctuations in numbers of strongyline and Fasciola eggs were pronounced.

Animals↗

The influence of genotype on the development of glomerular lesions in mink with Aleutian disease virus.

In an attempt to document progression rate differences in the development of glomerular lesions in mink infected with Aleutian disease virus (ADV), the glomeruli of Aleutian and non-Aleutian mink experimentally infected with ADV were evaluated by light, fluorescent, and electron microscopy. The animals were also examined for the presence of interstitial infiltrate, neutrophils, and arterial lesions. One hundred percent of the Aleutian mink had glomerular cell proliferation and interstitial infiltrate, while 95% of the Aleutian and 41% of the non-Aleutian mink had neutrophilic infiltrates and arteritis, respectively. Of the non-Aleutian mink, 91, 83, 42, and 12.5% had glomerular cell proliferations, glomerular neutrophils, interstitial infiltrate, and arterial lesions in, that order. All the Aleutian mink had glomerular depositions of gamma-globulin (IgG) and complement (C3), whereas 75% of non-Aleutian mink had deposits of IgG and C3. One hundred percent of both genotypes had glomerular deposits of immunoglobulin M (IgM). Ultrastructural glomerular changes consisting primarily of depositions of granular electron-dense material on basement membranes were observed in Aleutian mink 6 weeks after infection and 12 weeks after infection in non-Aleutian mink. These findings document progression rate differences in the development of glomerular lesions in Aleutian disease-affected Aleutian and non-Aleutian mink. Further, they emphasize the need for exploration of pathogenetic mechanisms involved in progression rate differences in lesion development.

Aleutian Mink Disease↗

Study of the one-step growth curve of equine infectious anemia virus by immunofluorescence.

Primary horse leukocyte cultures were inoculated with 2 or 10 50% tissue culture infective doses (TCID(50)) of equine infectious anemia (EIA) virus per cell, and the titer of cell-associated and fluid-phase virus was determined from 1 to 72 hr postinoculation (PI). Cover slips were collected from 4 to 72 hr PI and stained for EIA viral antigen by the indirect immunofluorescent (FA) technique. Viral replication was detected after a latent period of approximately 18 to 24 hr and reached peak titers of approximately 10(4.5) to 10(6) TCID(50)/0.5 ml from 48 to 72 hr PI. The fluid phase contained 10(1) to 10(2) TCID(50)/0.5 ml more virus than the cells. Viral antigen was first detected by FA from 18 to 24 hr PI. Approximately 75% of the cells contained antigen in their cytoplasm 72 hr PI. The FA technique is a sensitive method for detecting EIA virus in horse leukocyte cultures.

Animals↗

Aleutian disease of mink. Prevention of lesions by immunosuppression.

Mink that were homozygous recessive for the Aleutian gene (aa) were inoculated with Aleutian disease virus (ADV) and simultaneously treated with cyclophosphamide (Cy). Control mink were inoculated with ADV. All mink were injected with bovine serum albumin (BSA) and their anti-BSA antibody response was measured to monitor the influence of drug therapy on the humoral antibody response. Formation of anti-BSA antibody was markedly suppressed and the hypergammaglobulinemia and development of AD lesions was inhibited in the Cy-treated mink. The non-Cy-treated control mink developed characteristic signs and lesions including glomerulonephritis and arteritis. The nontreated ADV-infected mink, but not the Cy-treated ADV-infected mink, had glomerular deposition of C3 and gamma globulin. Both groups had high titers of virus in their blood. These results indicate that the development of ADV lesions can be prevented by immunosuppressive treatment and further implicate host immune mechanisms in the pathogenesis of Aleutian disease.

Aleutian Mink Disease↗