L-ascorbic acid at physiological concentrations (10 micrograms/ml) increased alkaline phosphatase activity in the osteoblastlike rat osteosarcoma cell line, UMR-106. The increase was dose-dependent and detectable at 6 hours after the addition of 100 micrograms/ml ascorbic acid to the medium. Treatment of the cells with 100 micrograms/ml ascorbic acid potentiated the response of cAMP to both PTH and PGE1, while cell growth was inhibited. Furthermore, the number of colonies formed by the cells grown in the soft agar was significantly reduced by increasing concentrations of ascorbic acid. These results indicate that ascorbic acid might play some role in the differentiation of osteoblasts.

SUMMARY When 17 patients with Sjogren's syndrome, without apparent clinical manifestations of renal disease, were examined renal function studies frequently indicated abnormalities in their renal phosphate handling. The percentage tubular reabsorption of phosphate (%TRP) was decreased in six (35-3%), and maximal tubular reabsorption rate for phosphate (TmPO4/GFR) was low in eight (47.1%). In contrast, indices of renal calcium handling and serum parathyroid hormone levels were normal, suggesting that the abnormalities of phosphate metabolism were due not to extrinsic, but rather to intrinsic disease processes occurring in the kidney in Sjogren's syndrome. When the patients were divided into two groups according to the presence or absence of a renal tubular acidification defect (RTAD), patients with RTAD were younger (p<0-005), had longer disease duration (p

Effect of aldosterone on the dome formation in the reconstructed MDCK cell epithelia was studied.

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The sonographic textures of 10 parathyroid tumors in nine patients were examined and compared with their histologic features, particularly with the amount of fibrous trabeculae. The carcinomas containing a large amount of fibrous trabeculae, which is the most frequent finding in parathyroid cancer, were very echogenic. On the other hand, the adenomas without fibrous trabeculae showed a low echogenicity. These data suggest that the possibility of malignancy is high when the parathyroid tumor is found to be very echogenic.