Urinary calcium excretion balances intestinal calcium absorption and does not increase with calcifediol levels up to ~400 nmol/L (160 ng/mL). Supplementation
Calcifediol supplements have been used in some studies to improve vitamin D status. Indications for their use include vitamin D deficiency or insufficiency, refractory rickets (vitamin D resistant rickets), familial hypophosphatemia, hypoparathyroidism, hypocalcemia and renal osteodystrophy and, with calcium, in primary or corticosteroid-induced osteoporosis.Calcifediol may have advantages over cholecalciferol for the correction of vitamin D deficiency states. A review of the results of nine randomized control trials which compared oral doses of both, found that calcifediol was 3.2-fold more potent than cholecalciferol. Calcifediol is better absorbed from the intestine and has greater affinity for the vitamin-D-binding protein, both of which increase its bioavailability. Orally administered calcifediol has a much shorter half-life with faster elimination. These properties may be beneficial in people with intestinal malabsorption, obesity, or treated with certain other medications.In 2016, the FDA approved a formulation of calcifediol (Rayaldee) 60 microgram daily as a prescription medication to treat secondary hyperparathyroidism in patients with chronic kidney disease. Interactive pathway map
History
Research in the laboratory of Hector DeLuca identified 25(OH)D in 1968 and showed that the liver was necessary for its formation. The enzyme responsible for this synthesis, cholecalciferol 25-hydroxylase, was isolated in the same laboratory by Michael F. Holick in 1972. Research
Studies are ongoing comparing the effects of calcifediol with other forms of vitamin D including cholecalciferol in prevention and treatment of osteoporosis. See also
Hypervitaminosis D
Hypovitaminosis D
Vitamin D

References
External links
"Calcifediol". Drug Information Portal. U.S. National Library of Medicine.
Clear cell papillary renal cell carcinoma (CCPRCC) is a rare subtype of renal cell carcinoma (RCC) that has microscopic morphologic features of papillary renal cell carcinoma and clear cell renal cell carcinoma, yet is pathologically distinct based on molecular changes and immunohistochemistry. Pathology
CCPRCC classically has apical nuclei, i.e. the nucleus is adjacent to the luminal aspect. In most glandular structures the nuclei are usually basally located, i.e. in the cytoplasm adjacent to the basement membrane. They typically stain with CK7 and do not stain with TFE3 and AMACR. See also
Renal cancer
Renal cell carcinoma


== References ==