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Biomedical subjects

R Borland

Publications and source records attributed to R Borland.

At least 109 records · Page 6Linked to original sources
PubMed1981

In vitro responses of lymphocytes from cattle with advanced Mycobacterium paratuberculosis infection to homologous and heterologous antigens.

The accuracy with which the purified lymphocyte and whole blood modifications of the lymphocyte stimulation test were able to detect animals with clinical Johne's disease was compared with that of the complement fixation test and microscopic faecal examination. Confirmatory diagnosis of Johne's disease was based upon histopathological examination of intestinal tissue. False positive results were obtained only with the complement fixation test. The only test not giving rise to false negative results was the purified lymphocyte modification of the lymphocyte stimulation test using johnin at 20 micrograms/ml and avian tuberculin at 20 micrograms/ml or 2 micrograms/ml. The whole blood technique was less accurate than the purified lymphocyte technique for the in vitro detection of cell-mediated immune responses to antigens. The purified lymphocyte technique appears to have potential as an diagnostic test for Johne's disease in cattle and merits further evaluation.

Animals↗
PubMed1977

Morphologic character of transforming renal cell cultures derived from Wistar rats given dimethylnitrosamine.

The morphologic character of kidney cells during serial subculture following isolation from Wistar rats treated several hours to 1 week previously with a carcinogenic dose of dimethylnitrosamine (DMN; 60 mg/kg body weight following protein deprivation) was compared with the appearance of cultures derived from normal control rats. Apart from early signs of cell toxicity, cultures from DMN-treated rats appeared similar to those from untreated rats for the first four passages. Control cells underwent senescence usually by subculture 4, whereas the test cultures survived to express morphologic transformation (usually at subculture 5) as dense macroscopic colonies of piled up cells. In 18 of the 20 test cultures, the cell populations that persisted in continuous culture following expression of morphologic transformation were exclusively mesenchymal, closely resembling DMN-induced renal mesenchymal tumor cells in continuous culture. In the remaining 2 test cultures from DMN-treated rats, a persisting population of abnormal epithelium was present in addition to morphologically transformed mesenchymal cells. The occurrence of populations of altered mesenchymal and epithelial cells characterized by prolonged survival in vitro following isolation from rats shortly after treatment with a carcinogenic dose of DMN was believed to be related to the long-term induction in the rat kidney of a high incidence of mesenchymal tumors and a lower incidence of cortical epithelial tumors by the same dose schedule.

Animals↗
PubMed1977

Length of in vivo exposure to a carcinogenic dose of dimethylnitrosamine necessary for subsequent expression of morphological transformation by rat kidney cells in vitro.

Rat kidney cells isolated in vitro at intervals from one to 24 hours after the administration of a single, carcinogenic dose of dimethylnitrosamine (DMN) were characterized by the expression of morphological transformation and a prolonged life span. In cultures isolated four hours or more following the dose of DMN, morphological transformation was expressed at subculture five, but this effect was progressively delayed with earlier times of isolation. Relative to control kidney cell cultures, transformed cells exhibited enhanced proliferative properties evident from assays for plating efficiency and DNA synthesis. The capacity for increased cloning efficiency by the test cultures was acquired several subcultures after the expression of morphological transformation, while ability for colony formation in semi-solid media evolved later still. The results suggest that target cells permanently altered by the carcinogen are present one hour after the administration of DMN, but the effect is more significant by four hours.

Animals↗
PubMed1975

In vitro culture of cells isolate from dimethylnitrosamine-induced renal mesenchymal tumors of the rat. I. Qualitative morphology.

The in vitro morphology of cells isolated from renal mesenchymal tumors induced in rats by a single ip injection of dimethylnitrosamine was followed in short- and long-term culture. The morphology of cells isolated from normal rat-kidney cortex was studied for comparison. Primary tumor-cell isolates consisted of a range of mesenchymal cell forms interspersed between discrete, homogeneous islands of cohesive epithelium-like cells. The latter were presumably derived from renal parenchyma that had been engulfed within the in vivo neoplasm by proliferating tumor cells, since this epithelial component did not survive serial subculture. Established tumor cell lines consisted of a pleomorphic range of mesenchymal forms resembling the descriptions of various cell types in vitro, including fibroblasts, smooth muscle cells, and endothelial cells. A range of mesenchymal cell forms in culture therefore correlated with the heterogeneous histologic nature of the in vivo neoplasm in which fibroblasts, smooth muscle fibers, and endothelium-like cells were also represented. Multinucleate or polymorphonuclear giant cells were characteristic of tumor cell cultures, whereas large, expanded polygonal cells with longitudinal striations were characteristic of normal kidney cell cultures. Some tumor cell cultures were typified by cells with cytoplasmic vacuolation and some by the acquisition of an epithelioid form at high cell density, a change not preceded by islands of cohesive, epithelium-like cells at preconfluent stages.

Animals↗