Cyclic-AMP activates and calcium inhibits protein kinase activity in avian parathyroid glands.
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Biomedical subjects
Publications and source records attributed to M Pines.
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L-Canavanine competes with L-arginine for incorporation into vitellogenin secreted in vitro by the fat body of the female locust Locusta migratoria migratorioides. Incorporation of L-[guanidinooxy-14C]canavanine into vitellogenin has been established unequivocally by combined arginase and urease hydrolyses of the acid hydrolysate of antibody-precipitated canavanyl vitellogenin. Continued exposure of the fat body to canavanine decreases in vitro protein secretion but the proportion of canavanyl vitellogenin to native vitellogenin increases. Canavanine-mediated inhibition of fat body protein secretion is dependent on both the canavanine concentration and the arginine retention by the fat body. Canavanine replaces about 10% of the arginyl residues of canavanyl vitellogenin. The electrophoretic mobility of canavanyl vitellogenin is greater than that of native vitellogenin but the ability of this aberrant protein to react with vitellogenin antibody is unimpaired.
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1. Hydrocortisone increases in vivo incorporation of [14C] glucose into fetal liver glycogen in the last days of gestation, whereas in glucagon-treated fetuses, a slight decrease in the incorporation rate was found. 2. Hydrocortisone increases total synthetase activity as that of synthetase a but was without effect on fetal liver glycogen phosphorylase. 3. Glucagon causes a slight increase in phosphorylase a activity on days 19-21, and was without effect on the activities of synthetase a and total synthetase. 4. Dibutyryl cyclic AMP had no effect on the key enzymes of glycogen metabolism 1 h after injection in utero, whereas after 6 h an increase in phosphorylase a activity was found without any change in synthetase a activity.
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The purpose of this scanning electron microscope study was to observe the dentin-amalgam interface after utilizing a standard restorative liner and a single-component dentin adhesive. Continuous interface gaps of over 15 mu were observed in specimens containing no lining and Copal varnish. Discontinuous 5 microns gaps were observed in specimens treated with PQ1. Additionally, specimens treated with PQ1 exhibited resin interpenetration into the dentin surfaces.
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Gene expression and alkaline phosphatase (AP) activity, associated with chondrocyte differentiation, were evaluated in the epiphyses of normal and tibial dyschondroplasia (TD)-afflicted turkeys. In the normal turkey growth plate (GP), osteopontin (OPN) and type X collagen genes were expressed by the hypertrophic cells in both GP and secondary ossification center, parallel to manifestation of AP activity. Collagen type II gene expression was restricted to the nonhypertrophic chondrocytes at the upper part of the GP. OPN or collagen type X genes were not expressed within the TD lesion. However, these genes were expressed in areas proximal and distal to the lesion, suggesting that after reaching partial differentiation, chondrocytes within the developing TD lesion de-differentiate into cells that resemble chondrocytes in the prehypertrophic zone. This suggestion is supported by the observation that the cells in the lesion expressed the collagen type II gene. In some cases, the TD lesion was invaded by fibroblastlike cells that did not exhibit any AP activity or expressed the OPN gene. No lesions were observed in the secondary ossification centers.