dihydrotachysterol and Kidney-Diseases

Masking--hiding identities of treatments from the patient, physician and/or statistician--is a critical element in clinical trials. Wherever possible, masking is implemented to eliminate observational bias or systematic error. In this paper, general concepts of masking in clinical trials are examined. Specific masking procedures used in the "Growth Failure in Children with Renal Diseases" (GFRD) Clinical Trial are described. A method to evaluate the "success" of this masking procedure for physicians is introduced. For each randomized patient at each clinical center, the clinic director was asked to predict which treatment (1,25-dihydroxyvitamin D3 or dihydrotachysterol) was assigned. Results showed that 72% of responses initially indicated "absolutely no idea" of treatment. Additional analyses revealed that the number and percentage of "correct" guesses were essentially equal for the two treatment groups and that a patient's time on treatment did not affect the mask. We conclude that the mask of physicians in the GFRD Clinical Trial was well maintained.

Topics: Bias; Calcitriol; Child; Child, Preschool; Dihydrotachysterol; Double-Blind Method; Glomerular Filtration Rate; Growth Disorders; Humans; Infant; Kidney Diseases; Physicians; Research Design

The mechanism of the concentrating defect of hypercalcemia is explored by examining the effect of concomitant phosphate restriction. Rats were pair fed a normal phosphorus diet, without (group 1) or with dihydrotachysterol (group 2), or a low-phosphorus diet (group 3). Hypercalcemia was comparable in groups 2 (12.1 +/- 0.6 mg/dl) and 3 (11.8 +/- 0.4 mg/dl), but serum phosphate was lower in group 3 than group 2 (3.8 +/- 0.7 vs. 7.1 +/- 1.1 mg/dl, P less than 0.005). Group 2 rats had impaired maximum urinary concentration after 24 h of fluid deprivation (2,441 +/- 450 mosmol/kg H2O, P less than 0.001) compared with group 1 (3,263 +/- 466 mosmol/kg H2O) or group 3 (3,332 +/- 515 mosmol/kg H2O) animals. Polydipsia and polyuria were found in group 2 rats only. Tubular calcium reabsorption was higher in group 2 (83.1 +/- 33.5 mg/24 h, P less than 0.001) than group 1 (47.0 +/- 26.1 mg/24 h) or group 3 (52.8 +/- 19.3 mg/24 h) animals, and medullary calcium concentration was higher in group 2 (7.57 +/- 3.08 nmol/mg dry wt, P less than 0.05) as compared to group 1 (5.04 +/- 1.37 nmol/mg dry wt) or group 3 (5.32 +/- 0.98 nmol/mg dry wt) rats. Total medullary solute concentration was significantly higher in group 3 than group 2 animals. Thus phosphate restriction prevents the defect of urinary concentrating ability of chronic hypercalcemia, probably by decreasing tubular uptake and tissue accumulation of calcium.

Topics: Animals; Calcium; Dihydrotachysterol; Hypercalcemia; Kidney; Kidney Concentrating Ability; Kidney Diseases; Phosphates; Rats; Rats, Inbred Strains

Topics: Calcifediol; Calcitriol; Child; Cystinosis; Dihydrotachysterol; Ergocalciferols; Humans; Kidney Diseases; Vitamin D

Four patients had symptomless osteomalacia at the time of starting regular haemodialysis. After 21-40 months they became hypophosphataemic and developed disabling skeletal symptoms. In each case an exacerbation of histological osteomalacia was shown. Symptoms improved after measures designed to raise serum inorganic phosphate concentrations or vitamin D administration, or both. Patients undergoing maintenance haemodialysis should have their serum phosphate and alkaline phosphatase levels monitored every month. Predialysis phosphate levels below 1 mmol/1 (3 mg/100 ml) and rising serum alkaline phosphatase concentrations are danger signals. If the diagnosis is confirmed early aggressive treatment should be started.

Topics: Adolescent; Adult; Alkaline Phosphatase; Calcium; Dihydrotachysterol; Female; Humans; Kidney Diseases; Male; Osteomalacia; Phosphates; Renal Dialysis

Topics: Bicarbonates; Dihydrotachysterol; Female; Humans; Kidney Diseases; Mandible; Mandibular Condyle; Maxilla; Radiography, Panoramic; Syndrome; Temporomandibular Joint; Time Factors

Topics: Animals; Calcium; Dihydrotachysterol; Intestinal Absorption; Intestinal Mucosa; Kidney Diseases; Rats

Topics: Animals; Calcinosis; Chlorides; Condiments; Dihydrotachysterol; Female; Kidney; Kidney Diseases; Mercury; Rats; Species Specificity

Topics: Animals; Aortic Diseases; Calcinosis; Dihydrotachysterol; Estradiol; Kidney Diseases; Organophosphonates; Phloretin; Phosphates; Phosphoric Monoester Hydrolases; Rats; Skin Diseases

Topics: Acute Kidney Injury; Calcium; Dihydrotachysterol; Follow-Up Studies; Humans; Hypercalcemia; Hypoparathyroidism; Kidney Diseases; Kidney Function Tests; Urea; Vitamin D

Topics: Aging; Animals; Animals, Newborn; Aortic Diseases; Arteriosclerosis; Blood; Body Weight; Calcinosis; Coronary Disease; Dihydrotachysterol; Female; Hypercalcemia; In Vitro Techniques; Kidney Diseases; Lactation; Pregnancy; Pregnancy, Animal; Rats

Topics: Adenoma; Calcium; Calcium Phosphates; Dihydrotachysterol; Drug Therapy; Glycosuria; Glycosuria, Renal; Humans; Kidney; Kidney Diseases; Kidney Tubules; Osteomalacia; Parathyroid Neoplasms; Phosphates; Urine

Topics: Adipose Tissue; Alopecia; Aortic Diseases; Atrophy; Calcinosis; Cockayne Syndrome; Coronary Disease; Dihydrotachysterol; Emaciation; Kidney Diseases; Kyphosis; Muscular Atrophy; Osteosclerosis; Pathology; Pharmacology; Progeria; Rats; Research; Sex; Sex Characteristics; Skin Diseases; Tooth Abnormalities; Toxicology

Topics: Alloxan; Calcinosis; Cholecalciferol; Dihydrotachysterol; Ergocalciferols; Islands; Islets of Langerhans; Kidney Diseases; Kidney Tubules; Nephrocalcinosis; Pancreas; Pathology; Rats; Research

Topics: Calcification, Physiologic; Calciphylaxis; Dihydrotachysterol; Heart Diseases; Kidney Diseases; Kidney Tubules; Osteosclerosis; Ovalbumin

Topics: Calcium; Dihydrotachysterol; Humans; Hypercalcemia; Kidney; Kidney Diseases; Renal Insufficiency

Topics: Dihydrotachysterol; Kidney; Kidney Diseases; Research

Topics: Administration, Oral; Blood Vessels; Dihydrotachysterol; Humans; Hydrocortisone; Kidney Diseases; Myocarditis; Pharmaceutical Preparations; Phosphates; Vitamin D; Vitamins