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S Hough

Publications and source records attributed to S Hough.

29 records · Page 2Linked to original sources
PubMed1983

Vitamin D metabolism in the chronic streptozotocin-induced diabetic rat.

Alterations in circulating vitamin D3 metabolites have been documented in both experimental and human diabetes mellitus. Using a recirculating hepatic perfusion system and in vitro kidney mitochondrial assays, we studied vitamin D3 hydroxylation in control and insulin-deficient rats 6 weeks after the induction of streptozotocin-diabetes. Vitamin D3-25-hydroxylase activity, assessed by hepatic conversion of [3H]vitamin D3 to [3H]25-hydroxyvitamin D3 during a 4-h perfusion, was similar in diabetic and control animals. The hepatic degradation of 25-hydroxyvitamin D3 to more polar metabolites was also normal, as was glucuronide conjugation and biliary excretion of vitamin D3 metabolites. The chronic insulin-deficient state resulted in a significantly (P less than 0.01) decreased 1 alpha-hydroxylase activity and enhanced (P less than 0.001) renal 24-hydroxylase activity. These alterations in vitamin D metabolism may relate to the deranged mineral homeostasis and skeletal morphology observed in rats and humans with chronic insulin deficiency.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1982

Calcium homeostasis in chronic streptozotocin-induced diabetes mellitus in the rat.

Calcium homeostasis was studied in freely fed control, streptozotocin diabetic, long-term and short-term insulin-treated diabetic rats 7 wk after the induction of diabetes. In contrast to the short-term (5-12 day) diabetic rat model, intestinal absorption of calcium was markedly enhanced in chronically insulin-deficient animals. Moreover, conventional balance studies showed that these animals were in positive calcium balance despite severe hypercalciuria. Intestinal hyperabsorption of calcium in long-standing diabetic rats occurred despite low levels of circulating 1,25-dihydroxyvitamin D and hypercorticosteronism and was attended by hypercalcemia and suppression of both plasma parathyroid hormone (PTH) and urinary cyclic 3',5'-AMP (cAMP). Long-term insulin replacement completely normalized the intestinal hyperabsorption of calcium, corrected the plasma calcium, and significantly increased circulating PTH and urinary cAMP excretion. Insulin therapy also corrected the decreased plasma 1,25-dihydroxyvitamin D observed in untreated diabetic animals. Intestinal hyperabsorption of calcium appeared to be only partially corrected by short-term insulin therapy. The accumulated results reveal decided differences in calcium homeostasis and hormonal response between the rats with long-standing diabetes and those with diabetes of short duration.

Animals↗
PubMed1981

Alkaline phosphatase activity in chronic streptozotocin-induced insulin deficiency in the rat: effect of insulin replacement.

Alterations in circulating alkaline phosphatase have been described in both man and the experimental animal with chronic insulin deficiency. We evaluated plasma and tissue alkaline phosphatase levels in freely-fed control, streptozotocin-induced diabetic and insulin-treated diabetic rats, seven weeks after the induction of diabetes. Circulating alkaline phosphatase activity was markedly elevated in the insulin deficient animal (p less than 0.001) and completely normalized following insulin administration. The elevated plasma alkaline phosphatase activity observed in the insulin deficient animals was heat-resistant and phenylalanine-sensitive, a pattern typical of the intestinal isoenzyme. Small intestinal alkaline phosphatase activity was significantly higher (p less than 0.01) in the diabetic animals, but comparable in the insulin-replaced and control rats. The intestinal isoenzyme activity was found to be strikingly insulin-sensitive; withholding insulin therapy for 36 hr prior to sacrifice resulted in an abrupt rise in both plasma and intestinal alkaline phosphatase values comparable to those observed in the insulin-deficient state. In contrast to these observations, skeletal alkaline phosphatase activity was decreased in the insulin deficient animal (p less than 0.01) and this abnormality was corrected by insulin replacement. Neither insulin deficiency nor insulin replacement resulted in any significant changes in the hepatic alkaline phosphatase isoenzyme.

Alkaline Phosphatase↗
PubMed1981

Isolated skeletal involvement in Cushing's syndrome: response to therapy.

A 38-yr-old male presented with severe symptomatic osteopenia secondary to adrenal hyperfunction without any clinical expression of Cushing's syndrome. The predominantly axial distribution of his osteopenia and the presence of rib fractures healing with abundant callus formation, despite insignificant elevations in serum alkaline phosphatase, were characteristic of glucocorticoid excess syndromes. The histological features of the pretreatment bone biopsy were typical of those associated with excess glucocorticoids, namely decreased quantities of nonmineralized bone matrix, reflecting sites of bone formation, and an increase in the number of osteoclasts, indicating enhanced bone resorption. Six weeks after adrenalectomy, repeat bone biopsy revealed a marked increase in bone matrix synthesis and a significant decrease in bone resorption. These observations suggest that stimulators of skeletal turnover, like sodium fluoride, may be inappropriate in the initial treatment of steroid-induced osteopenia after surgical cure and that vitamin D and calcium therapy offers a more rational approach. Furthermore, the importance of the routine evaluation of adrenal function in any patient presenting with osteopenia is stressed, as well as the fact that relatively isolated skeletal involvement, classically described in micronodular adrenal disease, is not necessarily peculiar to a specific subset of the syndrome but may potentially attend any cause of glucocorticoid excess.

Adrenal Cortex Function Tests↗
PubMed1981

Alterations in circulating vitamin D metabolites in the young insulin-dependent diabetic.

To assess the relationship between the decreased bone mass observed in young insulin-requiring diabetic patients and vitamin D metabolism, we measured serum 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D concentration in 45 white, insulin-dependent diabetic subjects, 7-18 yr of age. Metacarpal cortical thickness in 87% of these diabetics was below the mean for their respective ages, while 16% had a cortical thickness value greater than 2 sDs below the mean. Serum calcium and phosphate concentrations were normal, immunoreactive parathyroid hormone was in the low normal range, and total serum alkaline phosphatase was elevated compared to age- and sex-matched controls. Circulating 24,25-dihydroxyvitamin D concentrations were significantly elevated, and 1,25-dihydroxyvitamin D was significantly decreased. The increase in 24,25-dihydroxyvitamin D was greater in the diabetics with the most severe bone loss and was maximally increased during the first 5 yr of clinical diabetes. No apparent correlation was seen between metabolic control, as measured by hemoglobin A1C and urine and plasma glucose, and the circulating levels of the vitamin D metabolites. Despite appropriate insulin replacement, alterations in vitamin D metabolism occur in the young insulin-dependent diabetic and could relate to the decrease in cortical bone mass observed in these patients.

24,25-Dihydroxyvitamin D 3↗
PubMed1978

Sterols in yeast subcellular fractions.

Yeast is the most primitive organism synthesizing substantial amounts of sterols. Because of this eucaryotic organism's versatility in growth conditions, ease of culture, well-defined genetic mechanism, and characteristic subcellar architecture, it is readily applied to studies of the role of sterols in the general economy of the cell. Sterols exist in two major forms, as the free sterol, or esterified with long chain fatty acids. The importance of sterols for this organism can be demonstrated using a naturally occurring antimycotic azasterol. This agent inhibits yeast growth. Three effects are seen on sterol synthesis: inhibition of the enzymes delta14-reductase, sterol methyltransferase, and methylene reductase. Cells cultured on respiratory substrates are more sensitive to inhibition than are cells growing on glucose. We have demonstrated a relationship between respiratory competency and sterol biosynthesis in this organism. Many mutants altered in sterol synthesis are respirationally defective and must grow fermentatively. One clone has temperature conditional respiration. Experiments with purified mitochondria, prepared from this mutant and its isogenic wildtype, show that the mutant organism is able to respire at the higher temperature but lacks the ability to couple respiration to phosphorylation. No similar loss is seen in the wild-type clones. Data are given which support the proposal that, for inclusion in mitochondrial structures, yeast cells may discriminate among sterols available from the total sterol pool in favor of ergosterol.

Azasteroids↗
PubMedDate not supplied

Managing hypersexual disorders in brain-injured clients.

Three case studies involving hypersexuality in brain-injured clients are illustrated. Two cases involved the inappropriate touching of the opposite sex, and the third case involved exhibitionism. In one case of touching, feedback was used to decrease inappropriate touching. In the other case of touching, scheduled massage was used to shift stimulus control to an appropriate setting. In the case of exhibitionism, a combination of self-monitoring, private self-stimulation and dating-skills training were used to suppress the behaviour.

Adult↗