Vitamin D: two dihydroxylated metabolites are required for normal chicken egg hatchability

Effects of 1 alpha-hydroxyvitamin D3 and 24R,25-dihydroxyvitamin D3 on bone remodeling

The present study was undertaken to evaluate the effects of 1 alpha-hydroxyvitamin D3 and 24R,25-dihydroxyvitamin D3 on bone remodeling in dogs with osteomalacia induced by vitamin D depletion. To assess the rates of skeletal remodeling, intravital tetracycline labeling and morphometry of surface pattern were employed. Either vitamin D3 derivative accelerated the appositional growth rate, increased the percentage of osteoid seams labeled, and decreased the number, width, and perimeter of new osteoid seams. But the derivatives differed in bone resorbing activity: 1 alpha-hydroxyvitamin D3 increased the number and perimeter of resorption sites whereas 24R,25-dihydroxyvitamin D3 decreased them. Thus the results show that the former is a better bone remodeler while the latter may be useful in treating osteoporosis.

Dental management for children with chronic renal failure undergoing hemodialysis therapy

Patients with chronic renal failure who are undergoing hemodialysis therapy demonstrate problems of significant importance for dental treatment. A case is presented in which secondard hyperparathyroidism, resulting from renal failure and hemodialysis, was noted in a child. Other relationships between renal failure, hemodialysis, and dental care were also presented.