Search PubMed⌕ Search

Biomedical subjects

R T Cook

Publications and source records attributed to R T Cook.

At least 37 records · Page 2Linked to original sources
PubMed1979

The evaluation of liver function after partial hepatectomy in the rat: serum changes.

In serial studies of hepatic function in rats after 70% partial hepatectomy, quantitative changes were found in several of the serum components used clinically to assess liver status. The activities of the following enzymes were found to increase: gamma-glutamyl transpeptidase and lactic dehydrogenase were maximal 6 h postoperatively, while glutamic oxaloacetic transaminase and alkaline phosphatase reached peak values at 24 and 48 h respectively. Albumin levels were found to be relatively constant during the study; however, total protein concentration was lowest 6--12 h postoperatively, paralleling a decrease in globulin concentration. Bilirubin levels were elevated to 4x normal within 12 h after surgery. After partial hepatectomy calcium and phosphorus concentrations were significantly decreased at 24 and 12 h respectively. With the exception of alkaline phosphatase, the activities of all serum components measured returned to normal levels by 1 week after surgery; the alkaline phosphatase concentration continued to be elevated 2 weeks postoperatively.

Animals↗
PubMed1978

Mobility of cells from solid tumors.

The mobility of cells from two established cell lines of hamster origin, NIL B and its SV40 virus-transformant SV-NIL, was studied in cellular aggregates maintained in agitated liquid medium. Subcutaneous injection of 5 x 10(6) NIL B or SV-NIL cells into Syrian hamsters resulted in a high frequency of tumor formation - 1.00 for SV-NIL cells and 0.93 for NIL B cells. Cells from five different tumors of NIL B origin were grown in tissue culture and their mobility in cellular aggregates was also studied. The mobilities of the tumor-derived cells were similar to each other and to that of the SV-NIL cells, but slightly higher than that of the NIL B cells. In addition, the plating efficiency, saturation density and doubling time of NIL B, SV-NIL and the tumor-derived cells were determined in conventional flat culture. No consistent pattern of saturation density or doubling time was observed in the tumor-derived cells with respect to each other or to the established lines; however, the plating efficiencies of the tumor-derived cells were all considerably lower than those of NIL B and SV-NIL cells. It was concluded that selection for the ability to divide and survive in vivo (i.e. to form tumors) was accompanied by a modest increase in cell mobility in vitro.

Animals↗
PubMed1977

Metabolism of 7,12,-dimethylbenz(a)anthracene by normal and regenerating rat livers.

The in vitro metabolisms of [14C]7,12-dimethylbenz(a)anthracene (DMBA) by post-mitochondrial supernates and microsomes from intact and regenerating rat livers were compared. Both cell fractions from regenerating livers at 48, 72, and 96 h after partial hepatectomy metabolized less [14C]DMBA than similar fractions from intact livers. Prior in vivo treatment with DMBA enhanced metabolism by the cell fractions from both groups, but specific activities of cell fractions from regenerating livers were always about 60% or less of those from intact livers. Thin-layer chromatographic analysis of metabolites formed in incubations using either cell fraction failed to reveal distinct differences between ether-soluble or water-soluble products of similar fractions from intact and regenerating livers. However, highly reproducible differences were found between chromatograms of water-soluble metabolites formed by microsomes and post-mitochondrial supernates in both intact and regenerating livers. Extrapolations from these studies indicate large differences in the metabolic capacity of intact and regenerating livers when expressed on a whole-liver basis, but it is suggested that there may be additional factors contributing to the increased retention of DMBA by regenerating livers.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1977

Periodontal osseous defects associated with vitally submerged roots.

1. Vital roots associated with periodontal osseous defects can be clinically submerged beneath a soft tissue flap. 2. Connective tissue fibers filled the submerged osseous defects and were oriented parallel to the root surfaces in the majority of cases. 3. New cementum lined the root surface at the base of two successfully submerged defects, but was not apparent on the dentin amputation sites of any submerged roots. 4. Eight of the nine clinically submerged defects exhibited positive radiographic changes. The six control defects showed no positive radiographic changes. 5. All successfully submerged defects showed histologic evidence of new bone formation. New bone formation was not apparent in any of the control defects or nonsubmerged defects. 6. Either no epithelium or only a narrow band of epithelium was associated with the successfully submerged roots. A connective tissue inflammatory infiltrate was not present within the submerged defects. 7. The defects of all control teeth and nonsubmerged experimental roots contained epithelial downgrowth accompanied by a chronic inflammatory response in the connective tissue. 8. Pulpal tissues associated with submerged roots appeared vital without significant degenerative or inflammatory changes. Pulpal tissue was continuous with overlying connective tissue.

Adult↗
PubMed1975

The persistence of unmetabolized 3H-7,12-dimethylbenz(a)anthracene in regenerating rat liver.

The hepatic subcellular distribution, binding and persistence of 3H-7,12-dimethylbenz(a)anthracene were compared in partially hepatectomized rats and in intact controls. By 2 weeks after injection, intact liver homogenates contained only 9% of the total radioactivity present 4 h after injection; regenerated liver contained 60% in spite of a tripling in liver mass during this time. Cell fractions isolated from regenerated liver had 9-59 fold greater hexane extractable specific activities than those from intact liver. The radioactivity present in hexane extracts co-chromatographed with a 3H-7,12-dimethylbenz(a)anthracene standard. Preliminary experiments demonstrated that liver microsomes isolated from DMBA treated partially hepatectomized animals metabolized less DMBA in vitro than did microsomes isolated from DMBA treated intact animals. The greater persistence of unmetabolized DMBA may be related to the greater carcinogenicity of this compound for regenerating, as compared with intact, rat liver.

2-Acetylaminofluorene↗