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Biomedical subjects

C Thomas

Publications and source records attributed to C Thomas.

At least 559 records · Page 31Linked to original sources

The actin content of fibroblasts.

Cultures of chick skin fibroblasts were dissolved in solutions of sodium dodecyl sulphate, and their entire protein content was examined by gel electrophoresis. The most abundant species migrated in the same position as muscle actin. It gave a similar pattern of iodinated peptides after reaction with radioactive sodium iodide and digestion with proteinases, and contained comparable amounts of Nt-methylhistidine. Its amount was estimated by quantitative densitometry of stained gels with bovine serum albumin as an internal standard, and by radioactive assay of cultures that had been grown in the presence of [35S]methionine. The values obtained ranged from 7 to 14% of the total cellular protein, with an average of 8.5%. A protein band in the position of muscle myosin was also present and accounted for about 2.5% of the total protein. Both this and the actin band increased in relative amount with the age of the cultures.

Actins↗

Coronary bypass surgery. Value of maximal exercise testing in assessment of results.

To evaluate the relationship of results of maximal treadmill testing and results of saphenous vein bypass surgery (SVG), 30 patients underwent a maximal treadmill test before and after SVG; an additional 39 had results of postoperative exercise testing available. These patients were part of a group of 91 patients (95% of 96 survivors) who had complete right- and left-heart catheterizations and coronary angiography before and after operation. Twenty-one per cent had improved ejection fractions postoperatively; in 32% ejection fractions were worse. Duration of maximal treadmill exercise correlated poorly with ejection fraction changes or graft patency. Rate-pressure product (RPP) was usually lower postoperatively in patients with worse ejection fractions, primarily because of a low systolic blood pressure at maximum exercise. RPP postoperatively of less than 25,000 almost always meant poor surgical results, either graft occlusion or poor left ventricular function, while RPP of more than 30,000 meant that left ventricular function was preserved and all grafts or the graft to the anterior descending were patent. Thus, success or failure of SVG in these groups may be predicted without postoperative catheterization. An open graft to the anterior descending coronary generally insured a high RPP with exercise, even if other grafts were closed, as long as ventricular function remained good.

Angina Pectoris↗

DNA measurements on cell nuclei of normal, proliferating and neoplastic thyroid tissues in rats.

Nuclear DNA content was measured in 3 normal, 9 hyperplastic and 16 neoplastic rat thyroid glands. Thyroid hyperplasia and tumor growth were induced after treatment of the animals with X-rays and methylthiouracil. In the control animals only diploid thyroid epithelial cells were observed. At the stages of diffuse and nodular thyroid hyperplasia, the total DNA content per nucleus indicated for a diploid chromosome number and only a few cells were hyperdiploid. In the thyroid adenomas and carcinomas a scattering of the diploid region and an increase in the number of hyperdiploid cells was found. Among the various types of thyroid tumors neither difference in the number of hyperdiploid cells, nor typical pattern of distribution of these cells in the histogram was found. The increased number of hyperdiploid cells in the hyperplastic and neoplastic thyroids suggest an increase in the proportion of the cells entering the cell cycle and does not indicate for appearance of a neoplastic stemline.

Adenocarcinoma↗

Membrane damage in dehydrated bacteria and its repair.

The dehydration of bacteria by vacuum exposure results in damage to the cell membrane. This membrane damage does not necessarily lead to cell death. A part of the dehydrated bacteria is capable of eliminating the membrane damage by repair processes. Repair can proceed rapidly under conditions that permit synthesizing activities. The kinetics of this repair process were studied by means of the membrane-mediated biosynthesis of the cell wall as well as by the recovery of resistance to small concentrations of lysozyme. Repair is a precondition for cell proliferation. At low temperature cells can conserve their membrane damage and the repair process can be initiated when conditions become favourable.

Cell Division↗