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Biomedical subjects

G R Cain

Publications and source records attributed to G R Cain.

25 records · Page 2Linked to original sources

Presumptive neonatal isoerythrolysis in cats.

Entire or partial litters of 4 queens died due to hemolytic anemia within 1 to 2 days of birth. Necropsy and histologic examination of tissues from 6 dead kittens were indicative of neonatal isoerythrolysis. Blood samples from affected kittens were not available for study. Nevertheless, hemolysins and agglutinins in each queen's serum reacted with RBC from 2 sires of the affected litters. These antibodies, identified as anti-A, also reacted with the RBC from 64 random-source cats.

Agglutination Tests↗

Effect of continuous, whole-body gamma irradiation upon canine lymphohematopoietic (CFU-GM, CFU-L) progenitors and a possible hematopoietic regulatory population.

Clonogenic assays for granulocytes-macrophages (CFU-GM) in bone marrow and for T lymphocytes (CFU-L) in peripheral blood were performed on dogs continuously exposed to 60Co irradiation (0.02, 0.04, or 0.11 Gy/day). When decreased numbers of CFU-GM were observed they correlated well with the clinical status of the dogs but were not generally associated with increasing cumulative doses of absorbed irradiation. In clinically normal, irradiated animals, decreased CFU-GM values and myeloid-erythroid ratios were observed, suggesting that chronic irradiation may affect the granulocytic series well before decreased peripheral blood values are seen. In hypocellular dogs the number of CFU-GM were significantly decreased compared to values obtained from control or clinically normal irradiated dogs, while virtually no CFU-GM were observed in the leukemic dogs. Only the CFU-GM values of the hypocellular group showed an association, e.g., a suggestion of an abortive regenerative effort, with increasing absorbed dose. Proliferative capacity of T lymphocytes (CFU-L) was not affected by either increasing absorbed irradiation or the presence of leukemia. D0 values were determined on marrow fibroblastic cells to ascertain whether a radioresistant subpopulation of stromal elements would result from continuous in vivo irradiation. No correlation was found between absorbed dose and increased D0 values. However, seven of eight dogs which developed acute nonlymphocytic leukemia displayed marrow fibroblastic cells with elevated D0 values. These radioresistant marrow fibroblastic cells were assayed for their ability to support normal granulopoiesis and found to be not significantly different from control fibroblasts.

Animals↗

Kinetics of lymphohematopoietic progenitor cell populations in chronically irradiated RF/J mice.

Continuous protracted gamma irradiation (17.5 rad/22 h day for 28 days) resulted in significant life-shortening in RF/J mice due to lymphohematopoietic malignancies. The latency period of these neoplasms was decreased in irradiated RF/J versus unirradiated RF/J mice. No effect on leukemia incidence was observed in either irradiated or unirradiated CAF1 mice that served as control animals representing a strain with normal baseline lymphohematopoiesis. Lymphohematopoietic progenitor cell populations (CFU-GM and CFU-BL) were quantitated in unirradiated and chronically irradiated mice of both strains. The most remarkable differences in these parameters were seen with respect to CFU-BL. Unirradiated and irradiated RF/J mice produced over three times as many CFU-BL as CAF1 mice. Tremendously expanded lymphoid progenitor cell compartments in the RF/J mice may reflect the presence of numerically increased sensitive targets subject to radiation-induced damage and transformation. During a 12-week recovery period, CFU-BL and CFU-GM in the RF/J mice exhibited enhanced regenerative capabilities and overcompensatory responses that surpassed homeostatic baseline levels. Despite strain and strain X dose differences in CFU-BL and CFU-GM, no significant strain X dose relationships were seen in circulating leukocyte counts. This heightened proliferative activity and temporary overstimulation of radiation-damaged lymphohematopoietic tissues may allow sufficient promotional effect for leukemogenesis.

Animals↗

Detrusor myopathy in young beagle dogs.

Hematoxylin and eosin-stained sections of urinary bladder were examined microscopically from 449 male and female beagle dogs after 2- to 4-week toxicology studies. Degenerative lesions (detrusor myopathy) of the urinary bladder muscular tunic were present in 59 of 449 (13%) dogs. Myopathic lesions consisted of focal to multifocal areas of smooth muscle fiber atrophy with cytoplasmic basophilia and vacuolation, individual cell necrosis, enlarged smooth muscle nuclei and nucleoli, and occasional mitotic figures. Adjacent areas of arteritis and periarteritis were present in 10 of 59 (17%) beagles with detrusor myopathy suggesting a possible ischemic pathogenesis of the smooth muscle lesions. There was no significant difference in prevalence of myopathy in beagles administered vehicle or various test compounds. Prior urinary catheterization procedures appeared to augment the prevalence of myopathy; some lesions were adjacent to minor, iatrogenically traumatized urinary bladder mucosa. Muscle lesions were not observed in urinary bladders from mongrel dogs, monkeys, cats, rats, or microswine. When compared to crossbred dogs and other laboratory species, the beagle dog thus appears to be sensitive to development of detrusor myopathy.

Animals↗