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Biomedical subjects

J Nisbet

Publications and source records attributed to J Nisbet.

8 recordsLinked to original sources
PubMed1992

Blunted seasonal variation in serum 25-hydroxy vitamin D and increased risk of osteomalacia in vegetarian London Asians.

Serum 25-hydroxy vitamin D levels were measured in 297 adult Asians and 68 white subjects at different times of year and seasonal variation compared between subjects grouped according to ethnic origin, religion and dietary habit. A sub-group of Asians with symptoms and biochemical changes suggestive of osteomalacia underwent bone biopsy, and static bone histomorphometry was performed. Histological osteomalacia was detected in 15 Asians and borderline changes in 13. The majority of these cases were among vegetarian Hindus. Significant seasonal variation in 25-hydroxy vitamin D was observed in all groups, but with lower peak and trough levels among Asians, and especially the Hindus and vegetarian Asians. Summer rises in 25-hydroxy vitamin D levels were blunted among Hindus and vegetarian Asians, compared to whites, Muslims and non-vegetarian Asians. Vegetarian Asians had significantly lower serum calcium and higher PTH levels than non-vegetarians, but multivariate analysis indicated that this was an effect of osteomalacia, not vegetarianism. We conclude that solar exposure has a significant effect on vitamin D status in Asians resident in London. Non-vegetarian Asians have similar rise and peak levels to whites, but those taking a vegetarian diet (in particular, Hindus) have an impaired seasonal rise in 25-hydroxy vitamin D levels, and are at particular risk of metabolic bone disease. This effect did not appear to be mediated through secondary hyperparathyroidism consequent on a vegetarian diet.

Adult↗
PubMed1986

Tumor cachexia and hypercalcemia in nude rats and mice bearing human renal carcinomas.

Human hypercalcemia-inducing renal tumors have been established as xenografts in nude mice and nude rats. Animals bearing these tumors became cachexic and hypercalcemic and these changes could be reversed by excision of xenograft tumors. Metabolic studies carried out in nude rats suggested that the hypercalcemia-inducing factor was effecting renal excretion of calcium but was probably not parathyroid hormone. Although the hypercalcemia-inducing property of the tumor was stable throughout serial transplantation of tumor from animal to animal, it was lost after passage through cells in culture.

Animals↗