Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies from this laboratory demonstrated that secondary hyperparathyroidism in dogs with chronic renal disease may occur, at least in part, as a consequence of the need for progressive adaptation in renal phosphorus (P) excretion that occurs as glomerular filtration rate falls. However, the studies were of relatively short duration. Moreover, no information emerged regarding a potential role of calcium malabsorption in the pathogenesis of secondary hyperparathyroidism. The short duration of the protocol did not lend itself to the study of the effect of P control or the administration of vitamin D in the pathogenesis of renal osteodystrophy. In the present studies, 14 dogs with experimental chronic renal disease were studied serially for a period of 2 yr. Each animal was studied first with two normal kidneys on an intake of P of 1,200 mg/day. Then, renal insufficiency was produced by 5/6 nephrectomy. The dogs then were divided into three groups. In group I, 1,200 mg/day P intake was administered for the full 2 yr. In group II, P intake was reduced from the initial 1,200 mg/day, in proportion to the measured fall in glomerular filtration rate, in an effort to obviate the renal adaptation in P excretion. In group III, "proportional reduction" of P intake also was employed; but in addition, 20 mug of 25(OH)D(3) were administered orally three times a week. In group I, parathyroid hormone (PTH) levels rose throughout the 2-yr period reaching a final concentration of 557+/-70 U (normal 10-60). In group II, values for PTH remained normal throughout the 1st yr, increased modestly between the 12th and the 18th mo, but then did not rise after the 18th mo. In group III, no elevation of PTH levels was observed at any time; however, these animals were hypercalcemic. Histomorphologic analyses of the ribs of these dogs were performed serially throughout the 2-yr period. A linear relationship was obtained between the osteoclastic resorption surface and the concentration of circulating immunoreactive PTH. The osteoid volume was greater in group I animals when compared to those in group II. None of the morphologic abnormalities associated with renal osteodystrophy were observed in the animals in the third group.
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PMID:Phosphate control and 25-hydroxycholecalciferol administration in preventing experimental renal osteodystrophy in the dog. 87 95

Intestinal absorption of calcium was evaluated in 6 uraemic patients and in 7 control subjects by a two isotope technique exploring absorption in the four hours following ingestion of the dose. In the first two hours, calcium absorption in the patients was markedly lower than normal and was corrected by 6-10 day administration of dihydrotachysterol, 0.66 mg per day. The administration of 0.33 mg per day proved less effective. The data indicate the existence of impaired intestinal calcium absorption in chronic renal failure and reversal of the defect after DHT administration. The method of investigation appears to be a valid procedure for the study of calcium malabsorption of CRF and in the evaluation of the effect of vitamin D metabolities and analogs.
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PMID:Defective calcium absorption in the proximal small intestine in chronic renal failure: effect of dihydrotachysterol. 94 Jan 79

The pathogenesis, clinical course and treatment of senile-postmenopausal osteoporosis are reviewed. It is likely that several factors, including genetic and racial determinants as well as nutritional calcium and/or vitamin D deficiency in the elderly play a pathogenic role. Available data are consistent with the possibility that the primary alteration of bone metabolism in senile-postmenopausal osteoporosis may be a decrease in de-novo bone formation below the level necessary to compensate for age-related bone loss. The second part of the study deals with the osteomalacia syndrome. The most common known causes of osteomalacia are vitamin D deficiency, especially secondary to malabsorption, and a defective vitamin D metabolism associated with chronic renal insufficiency or prolonged anticonvulsant therapy. The hypophosphatemic forms of osteomalacia may be induced by renal tubular dysfunction or by phosphate deficiency of other origin; in these disorders a pathogenic role of altered vitamin D metabolism has not yet been established.
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PMID:[Osteoporosis and osteomalacia]. 112 74

A permature male infant required intravenous alimentation for six weeks following extensive surgery for ileal and cecal necrosis. At 3 months he developed evidence of hepatitis. Subsequently osteoporosis and the Fanconi syndrome appeared. Urine phosphate clearance was 83 percent of creatinine clearance at a serum phosphate concentration of 1.6 mg/dl. Concentration of plasma immunoreactive parathyroid hormone was elevated at 550 pg/ml. 25-Hydroxycholecalciferol was given at 240 mug/day. Aminoaciduria disappeared and bone healing occurred. Serum phosphate rose to 6.5 mg/dl and phosphate clearance fell to 2 percent of creatinine clearance. Upon cessation of 25-OHCC therapy, the Fanconi syndrome recurred despite administration of vitamin D2. 25-OHCC was then administered at 40 mug/day, and the urine abnormalities were reversed. The patient probably developed hyperparathyroidism, secondary malabsorption, and hepatitis. The Fanconi syndrome was the consequence of the hyperparathyroidism. 25-OHCC therapy was more effective than vitamin D in reversing the disordered state, possibly because of impaired hepatic metabolism of vitamin D2.
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PMID:Fanconi syndrome following bowel surgery and hepatitis reversed by 25-hydroxycholecalciferol. 112 25

Mild rickets was present in 7, and 3 others with severe bone disease developed widespread skeletal demineralization and multiple fractures. The intake of vitamin D was apparently loosely related to the severity of the osteodystrophy. The latter however, was closely linked to both the serum inorganic phosphate and the calciumXphosphate product. The serum calcium was directly related to the infant's gestational maturity, hypocalcaemia being present in those born before 35 weeks. Pathogenetic factors have probably included reactive hyperparathyroidism and nutritional deprivation associated with preterm delivery. Five of the infants who had biliary atresia developed radiological evidence of osteoporosis from about twelve months of age. This may be related to protracted calcium malabsorption, but its true nature remains to be elucidated.
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PMID:The osteodystrophy of prolonged obstructive liver disease in childhood. 125 25

It is well known that osteoporosis is more common in chronic alcoholists than in age-matched controls. Possible aetiological factors could be: malabsorption of calcium and vitamin D, liver disease, abnormal parathyroid function. With this study, the authors investigated parathyroid hormone (PTH) behaviour in thirteen selected patients with alcohol abuse, free from any clinical or humoral sign of hepatopathy, and in ten healthy subjects as a control group. In alcohol abusers a significant reduction of plasmatic PTH, compared to normal calcium levels were found. A possible direct interaction effect between ethyl alcohol and PTH may be suggested, even if further studies are required.
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PMID:Hypoparathyroidism in chronic alcohol intoxication: a preliminary report. 130 58

Cystic fibrosis is an inherited, multisystem disorder characterized by an abnormality in exocrine gland function. It leads to chronic pulmonary disease in most cases and pancreatic insufficiency in 85 percent of patients. Although this disease is not uncommon in Caucasians, it has been considered very rare among Japanese. The majority of patients are diagnosed in infancy or childhood. The patient in this case report was a 45-year-old Japanese man who had not been diagnosed as having cystic fibrosis. This patient had recurrent episodes of pulmonary infection that started in childhood, and plain films of the chest showed increased interstitial markings, hyperaeration, and bronchiectasis. CT of the upper abdomen showed a generally enlarged pancreas with complete fatty replacement. Serum and urine pancreatic enzyme levels were low, suggesting pancreatic insufficiency. Repeated sweat tests were positive. A roentgenologic skeletal survey showed general demineralization, which may be multifactorial. In this case, it was concluded that vitamin D deficiency caused by vitamin D malabsorption and/or insufficient sunlight exposure was mainly responsible for the demineralization and that chronic respiratory acidosis might also be partially responsible.
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PMID:A Japanese adult case of cystic fibrosis causing bone demineralization. 141 May 64

The influence of insulin on plasma and bone mineral homeostasis was studied in the BB rat model, which develops an autoimmune form of diabetes at the age of about 100 days. Untreated diabetes of short duration resulted in hypercalciuria and intestinal calcium malabsorption despite increased free concentrations of serum 1,25-dihydroxyvitamin D. The concentrations of two vitamin D-dependent calcium-binding proteins were also decreased: a low duodenal calbindin-D 9K concentration corresponding to the low intestinal active calcium absorption and a low serum osteocalcin concentration, corresponding to a low bone formation and highly correlated with serum IGF-I concentration. Indeed, on bone histology a very low number of osteoblasts and low osteoblast activity (osteoid formation and mineral apposition rate) were observed. Similar abnormalities persisted in rats with long-standing diabetes resulting in markedly decreased bone mass and increased brittleness of bone. Diabetes therefore resulted in low-turnover osteoporosis. Several hormones (testosterone, growth hormone and 1,25-dihydroxyvitamin D) and growth factors (IGF-I and its binding proteins) with known effects on bone were markedly decreased in diabetic rats. A continuous infusion of testosterone, GH or 1,25-(OH)2D3 for 14 d by miniosmotic pumps could not improve the biochemical or histomorphometric abnormalities. Insulin infusion for 2 weeks, however, rapidly increased and overcorrected the number of osteoblasts, normalized serum osteocalcin and IGF-I concentrations but could not yet normalize bone mineralization. Continuous infusion of IGF-I alone did not improve the osteoblast number of osteocalcin but markedly stimulated bone mineralization. From these data we can conclude that both insulin and IGF-I are potent bone growth factors but with different mode of action. In human type 1 diabetes, a similar decrease in serum osteocalcin and IGF-I was observed. A reduction of regional bone mass, both in long and trabecular bones, is frequently observed in human diabetes. Cumulative data from case control studies indicate that the life-time fracture risk is increased in diabetes.
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PMID:Diabetic bone disease. Low turnover osteoporosis related to decreased IGF-I production. 146 60

In clinically active Crohn's disease the bone mineralization is impaired due to calcium malabsorption by the inflamed intestinal wall which is potentiated by diarrhoea and the thus accelerated transit time. To this we must add the shortening of the gut after operations, the inadequate dietary calcium supply or possibly calcium elimination in case of concurrent lactose intolerance. Corticoid treatment leads also to deterioration of bone mineralization. This is the reason why the authors assessed in 98 patients with Crohn's disease the bone mineralization, using the method of clavicular bone index (NIBA). Then treatment was started: a high protein diet, calcium forte, Ossin (sodium fluoride), vitamin D forte, anabolics and regular physical exercise. Check-up examinations after one year revealed that the index was restored in the majority of patients (60.84%) to normal. The above treatment is thus effective. It must be, however, regular and of a long-term character, in some patients it must extend over many years. We had, however, also patients who although subjected to an extensive resection of the gut and treated for prolonged periods with corticoids, had permanently an index between 100 and 120% without treatment.
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PMID:[Prevalence of bone decalcification in the treatment of Crohn's disease]. 148 71

Serum 25-hydroxyvitamin D declines in elderly subjects. This decrease reflects, in part, a lower vitamin D intake. But changes in serum 25-hydroxyvitamin D are more marked in the northern latitudes of the world because less vitamin D synthesis occurs n the skin as a result of a reduced amount of ultraviolet light. Consequently, vitamin D deficiency leading to osteomalacia is more common in thr northern latitudes, particularly among the elderly. The Recommended Daily Allowance of 200 IU of vitamin D in the elderly may be insufficient, since higher doses of 800 IU/day have been shown to reduce the incidence of osteoporotic fractures. The use of more potent analogues of vitamin D, such as calcitriol (Rocaltrol), should be reserved only for those patients who have established vertebral osteoporosis and who generally have more pronounced malabsorption of calcium.
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PMID:Vitamin D metabolism and therapy in elderly subjects. 150 13


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