Abstract
In hyperthyroid and hypothyroid rats myocardial infarction was produced by coronary artery ligature. At different times following the ligature the animals were given 3H-thymidine or 3H-proline. The following parameters were determined: the number of DNA- and tropocollagen-synthesizing connective-tissue cells at the infarction border and at the infarction site; the mean silver-grain density above the nuclei or cells; the duration of one cell cycle; and the number of mitoses. The labelling and mitotic indices as well as the percentage of the standard deviation from the mean values were estimated. The following results were obtained: 1. In hyperthyroidism wound healing is accelerated. The number of DNA-synthesizing connective-tissue cells is increased. The cell-cycles are shorter. The release of tropocollagen by the fibroblasts takes place at a strikingly fast rate. 2. In hypothyroidism wound healing is delayed. The 3H-thymidine and mitotic indices are lowered. The release of tropocollagen is slowed down. The granulation tissue contains localized accumulations of mucopolysaccharides.
Published Version
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