Thyroid cells, obtained from both normal human tissue and benign nodular goiter, were cultured and maintained in vitro in 4-18 passages. Cultures with confluent cells accumulated cyclic AMP (10-150 times the basal amount) upon addition of bovine thyrotropin (100 milliunits/ml), indicating that the cells in culture maintained a thyrotropin-sensitive adenylate cyclase system. Addition of high doses of thyrotropin also induced a characteristic and reversible change in the morphology of the cells.The effect of thyrotropin on cell growth was studied in short- (HtTh 14). The tissue was fragmented with a scalpel, suspended in phosphate-buffered saline containing 1 mg of collagenase per ml, and incubated in a 37°C rocking waterbath for 60 min. Cells were further liberated from the fragments by pipetting. Large fragments were allowed to sediment and the supernatant was decanted and centrifuged (200 X g for 10 min). The pellets were suspended in Eagle's minimum essential medium (14) supplemented with 10% fetal calf serum, 100 units of penicillin, 1.25 ,gg of amphotericin B, and 50 ,ug of streptomycin per ml. The cells were incubated in 50-mm Nunc petri dishes (Nunc, Roskilde, Denmark). About 20 dishes were initiated from 1 g of wet weight tissue. The cultures were incubated at 37°C in a humidified atmosphere containing 5% CO2. Primary confluent monolayers were usually formed within 7-14 days. The cultures were then subcultivated at 1:2 split ratio. Cells were detached after incubation in phosphate-buffered saline with 0.02% EDTA for 5 min followed by a film of phosphate-buffered saline with 0.25% trypsin for about 10 min. Cultures of normal human skin fibroblasts and human glial cells were initiated and maintained as described (15,16 Abbreviation: TSH, thyrotropin.
A nucleoside diphosphate kinase has been highly purified from baker's yeast, and has been obtained in a crystalline form from an ethanol-containing medium. The results indicate that the amino acid sequence around the reactive 1-phosphohistidine of the yeast enzyme is different from that of human erythrocytic and bovine liver nucleoside diphosphate kinase.
Serum concentrations of apolipoprotein (apo) A-I. A-II and B were determined in 28 diabetic children (age 3-16 years) and 14 healthy matched controls. In the healthy children the serum apo A-I concentration was 120 +/- 20 arbitrary units (A.U.) (mean +/- S.D.), apo A-II 111 +/- 14 A.U. and apo B 100 +/- 34 A.U. (100 A.U. = mean concentration in adult blood donors). The apo A-I concentration was significantly higher in the diabetic children (134 +/- 13; p less than 0.02) than in the healthy controls. In diabetics apo A-II was 116 +/- 14 A.U. and apo B 106 +/- 21 A.U., values not significantly different from those in the controls. The serum cholesterol concentration in the healthy children correlated strongly to apo A-I and apo A-II, which was not the case in the diabetics. The differences between diabetic and healthy children with respect to correlations between the apolipoproteins and the serum lipids might indicate a different apolipoprotein/lipoprotein lipid relationship in diabetics.
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