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Biomedical subjects

R H Wasserman

Publications and source records attributed to R H Wasserman.

At least 109 records · Page 6Linked to original sources
PubMed1975

Depressed duodenal calcium absorption in the diabetic rat: restoration by Solanum malacoxylon.

Duodenal calcium absorption is depressed in alloxan and streptozotocin diabetic rats taking normal amounts to dietary vitamin D. Depression of absorption appears to be at least in part the result of altered metabolism of vitamin D with failure to form 1,25-dihydroxycholecalciferol (1,25-(OH)2D3), the vitamin D metabolite that acts directly on duodenum to stimulate calcium absorption. The South American plant Solanum malacoxylon causes extensive soft tissue calcification when ingested by cattle. An extract of this plant restores calcium absorption depressed by dietary strontium blockage of 1,25-(OH)2D3 formation in chicks. We gave an aqueous extract of S. malacoxylon to diabetic rats and restored duodenal calcium absorption to normal. These findings provide further evidence of the ability of a factor in the S. malacoxylon extract to mimic the actions of 1,25-(OH)2D3 on duodenal calcium transport and reinforce the hypothesis that abnormal vitamin D metabolism is an important determinant of depressed duodenal calcium absorption in diabetes.

Animals↗
PubMed1975

Hypercalcemia and calcinosis in Florida horses: implication of the shrub, Cestrum diurnum, as the causative agent.

A chronic debilitating disease is described in Florida horses. There is progress weight loss and lameness of increasing severity. Plasma calcium is elevated to moderate or severe degree. Anatomical changes include dystrophic calcinosis of elastic tissues, viz. major arteries, tendons and ligaments. A generalized osteopetrosis is present and may be related to hypoparathyroidsim and hypercalcitoninism. The presence of Cestrum diurnum (day-blooming jessamine, day cestrum, wild jasmin) in areas accessible to affected animals, the observation that leaves of the plant were stripped in these areas, and the finding of a potent, active vitamin D-like substance in this plant constitute strong evidence that Cestrum diurnum is the agent causing the abnormalities of mineral metabolism.

Animals↗
PubMed1975

Cestrum diurnum poisoning in Florida cattle.

Cestrum diurnum poisoning was described in a Florida bull. Clinical signs included chronic wasting and progressive lameness. Plasma calcium was elevated for long periods of time but decreased toward low normal values. There was pronounced C-cell hyperplasia. Osteopetrosis was very severe and reflected retarded osteocytic osteolysis and chondrolysis. Further negative effects on the osteocytes eventually lead to osteonecrosis. Soft tissue calcinosis involved tendons and ligaments, major arteries and veins but kidneys and lungs were spared. Whereas the osteopetrosis could be explained by hypercalcitoninism, the osteonecrosis was believed to result from direct action by the Cestrum diurnum factor, previously shown to have an action similar to that of 1,25-dihydroxy-cholecalciferol, which is the biologically active metabolite of vitamin D3.

Adrenal Glands↗
PubMed1975

Metabolism, function and clinical aspects of vitamin D.

Briefly reviewed herein are some of the contemporary findings on the metabolism of vitamin D, and the biochemical and physiological effects of this steroid in the animal. Certainly the most accepted major action of vitamin D is to enhance the intestinal absorption of calcium. Historically, there is also considerable evidence that the vitamin D is required for the resorption of calcium from bone, thereby aiding in maintaining normal serum calcium levels. Increasing evidence is becoming available that vitamin D does have a direct effect at the kidney level, and that the absorption and metabolism of the phosphate ion is also significantly affected by this steroid. As a consequence of vitamin D administration to the rachitic animal, some molecular changes in the intestine have been identified and these include the induction of the vitamin D dependent calcium binding protein, an increase in intestinal levels of alkaline phosphatase and calcium ATPase, and a stimulation of the adenylate cyclase system. A hallmark of recent efforts is a further understanding of the metabolism of vitamin D and the formation of its most active form, 1,25-dihydroxycholecalciferol. All of this knowledge will prove valuable in the rational treatment of certain abnormalities of calcium and bone metabolism for which examples are already available.

Animals↗
PubMed1974

Calcium absorption and calcium-binding protein synthesis: solanum malacoxylon reverses strontium inhibition.

The ingestion of diets containing high concentrations of stable strontium inhibits calcium absorption and intestinal calcium-binding protein synthesis and, as shown by others, does so by inhibiting the conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol, the active form of vitamin D. The addition of the South American plant Solanum malacoxylon to strontium-containing diets counteracts the inhibitory action of dietary strontium, thereby indicating that the plant contains a factor which can mimic the action of 1,25-dihydroxycholecalciferol and representing the first such factor identified in a botanical source.

Animals↗
PubMed1974

Diphenylhydantoin: effects on calcium metabolism in the chick.

Rickets, hypocalcemia, decreased duodenal calcium transport, and reduction of calcium binding protein have been produced in chicks treated with diphenylhydantoin. These effects are directly related to diphenylhydantoin dose and inversely related to the intake of vitamin D(3) (cholecalciferol).

Animals↗