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Biomedical subjects

M Kaye

Publications and source records attributed to M Kaye.

At least 109 records · Page 6Linked to original sources
PubMed1977

The calcium and vitamin D status in an elderly female population and their response to administered supplemental vitamin D3.

Recent reports have implicated the importance of impaired calcium absorption, inadequate dietary vitamin D, and low serum vitamin D levels in the genesis of metabolic bone diseases in the elderly. This study evaluated the dietary intakes of calcium and Vitamin D, calcium absorption, and serum 25 hydroxycholecalciferol (25 OH D) levels in a population of women (mean age 83 yrs) compared to healthy volunteers (mean age 35 yrs). Dietary intakes of both calcium and vitamin D and serum 25 OH D levels were found to be comparable in both groups. Calcium absorption was normal in the subjects studied and did not change significantly after two 2-week periods of oral supplementation with vitamin D3 in doses of 500 I.U./day and 10,000 I.U./day, although the serum 25 OH D levels rose significantly and comparably in both groups. Thus other etiological factors may play relevant roles in the causation of bone diseases in the elderly and unless deficient dietary or serum vitamin D levels are demonstrated, empirical supplementation with vitamin D should not be undertaken. The differences of the above findings from previously published data are discussed.

Absorption↗
PubMed1977

Technetium-99m-pyrophosphate bone scans in hyperparathyroidism.

Most patients with primary hyperparathyroidism have normal 5-hr bone-to-soft-tissue ratios for 99MTc-pyrophosphate. In contrast, all five patients with advanced secondary hyperparathyroidism in this study showed significant (p less than 0.001) increases of bone uptake. In the early period after parathyroidectomy, there was no quantitative or qualitative change in uptake. A limited decrease of bone uptake was observed only after prolonged periods of observation. In itself, parathyroid activity seems to have little direct influence on bone uptake of 99MTc-pyrophosphate.

Adolescent↗
PubMed1976

Observations on the mechanism of 99mTc-labeled phosphate complex uptake in metabolic bone disease.

This communication describes a series of clinical and animal in vivo and in vitro investigations designed to elucidate the mechanism of 99mTc-Sn-phosphate complex concentration in metabolic bone disease. Rachitic and lathyritic animals were used as experimental models. Based on these studies it is concluded that 99mTc alters the pharmacology of the phosphate complexes, in particular pyrophosphate, which was the test agent most extensively employed, so that the usual affinity for mineral is for the greater part replaced by organic matrix binding. There is also evidence to suggest the immature collagen moiety of the organic matrix is the prime target of 99mTc-Sn-phosphate complex binding. Specifically, the aldehyde groups of the collagen molecule are suspected as being the major site of interaction.

Aminopropionitrile↗
PubMed1976

Relationship between bone uptake of 99mTc-pyrophosphate and hydroxyproline in blood and urine.

In a group of hospital patients with various diseases, the urinary hydroxyproline-to-creatinine ratio showed a significant correlation (r = 0.63; p less than 0.001) with the 5-hr bone-to-soft-tissue ratio for 99mTc-pyrophosphate uptake. In patients on chronic hemodialysis, a similar correlation was found between the 5-hr bone-to-soft-tissue ratio and hydroxyproline levels in plasma and serum. The findings suggest that 99mTc-pyrophosphate binding by bone is related to collagen metabolism.

Aged↗
PubMed1976

Abnormal 99mTechnetium-tin-pyrophosphate bone scans in chronic renal failure.

A high incidence of abnormal 99mTechnetium-tin-pyrophosphate (99mTcPPi) is reported in a population of chronic renal failure patients. Using the 5 hour bone to soft tissue ratio as a quantitative index of increased uptake, 78% of 45 long-term dialysis patients and a similar proportion of non-dialyzed chronic renal failure patients were found to have increased uptakes. In animal studies using a uremic model, similar increased uptakes of 99mTcPPi was found with evidence of increased vascularity as reflected by red cell or plasma volumes in the bone or by the uptake of concomitantly administered 45Ca. The evidence suggests that the abnormal bone scans reflect abnormalities in collagen metabolism that occurs in the uremic state and that 99mTcPPi scans are useful in the diagnosis and management of renal osteodystrophy.

Animals↗
PubMed1975

The direct effect of calcium on the hyperparathyroidism of chronic renal failure.

1. The direct effect of calcium on the hyperparathyroidism of chronic renal failure was studied in rats with induced chronic renal failure, who were fed on a diet low in phosphate and who received supplemental phosphate by injection. They were given a normal (0-8%), or (0-1%) or high (1-7%) calcium diet. 2. The animals on the low calcium diet had larger parathyroids and more severe bone disease at the end of 4 weeks, indicating the importance of calcium intake in directly influencing the degree of hyperparathyroidism. 3. Increasing the calcium content of the diet from 0-8% to 1-7% produced no additional benefits.

Animals↗
PubMed1975

Effects of fluoride on bone in chronic renal failure.

Fluoride is concentrated in the bones of patients with chronic renal failure when fluoridated water is used during hemodialysis. Excessive osteoid is produced that is not normally mineralized and severe osteomalacia occurs. Electron microscopical examination of iliac crest bone biopsy specimens from four patients suggests that fluoride induces the synthesis of disarrayed collagen by the activated osteoblasts. Collagen fibers were found to be normal in size and in axial periodicity.

Adult↗
PubMed1975

Technetium-99m-pyrophosphate kinetics and imaging in metabolic bone disease.

A study was undertaken to investigate the behavior of 99mTc-Sn-pyrophosphate complex in metabolic bone disease. Of clinical importance was the generalized increased periarticular bone accumulation of the radiopharmaceutical in osteomalacia and in combined osteomalacia and osteitis fibrosa as found in patients with chronic renal failure. The pattern in primary hyperparathyroidism was variable. There was no correlation between the initial rates of accumulation of the radiophosphate complex or its bone to soft-tissue uptake ratio at 5 hr when compared with the degree of osteomalacia and osteitis fibrosa. It is postulated that the 99mTc-Sn-pyrophosphate complex has greater affinity for immature collagen than the crystal surface.

Adenocarcinoma↗
PubMed1975

Technetium-99m-pyrophosphate: studies in vivo and in vitro.

In rats with induced rickets, the uptake of 99mTcO4 and 99mTc-pyrophosphate per gram of bone was increased as compared with weight-matched controls. However, the uptake of radioactive calcium and 32P-pyrophosphate was similar in both rachitic and control animals, suggesting that the 99mTc label conferred specificity and favored the rachitic lesions. Employing the rat tibia in an in vitro system, 99mTcO4 uptake was predominantly in the organic bone matrix; radioactive calcium, 32P-pyrophosphate, or 14C-diphosphonate uptake was mainly in the bone mineral; and 99mTc-pyrophosphate, 99mTc-diphosphonate, and 99mTc-polyphosphate were found in both mineral and organic phases. By removal of both mineral and polysaccharide and by using agents that altered the degree of collagen fibril cross-linking, evidence was obtained suggesting the 99mTcO4 and 99mTc-pyrophosphate are preferentially bound by immature collagen.

Animals↗
PubMed1974

Bone disease in hemodialysis patients with particular reference to the effect of fluoride.

Forty-one patients on our chronic hemodialysis program were assessed for the degree of progression of bone disease over an average period of 46 months. Seven patients were using a fluoridated dialysate. Four of these seven patients developed a marked increase in osteoid as judged by bone biopsy, while in the nonfluoridated group the amount of osteoid remained within normal limits.In the absence of fluoride, although osteitis fibrosa occurred, it was reversible in 10 out of 12 cases by dihydrotachysterol treatment, and overall there was no evidence of progression of bone disease at the end of the study period.

Adult↗
PubMed1974

The effects in the rat of varying intakes of dietary calcium, phosphorus, and hydrogen ion on hyperparathyroidism due to chronic renal failure.

Renal failure of 4 wk duration in rats led to parathyroid enlargement, increased bone resorption, and decreased tubular reabsorption of phosphate by the remnant kidney. The degree of hyperparathyroidism was influenced by each of the three dietary factors investigated. In the first study increasing calcium intake reduced the size of the parathyroids by increasing calcium and reducing phosphate absorption. In the second study phosphate intake was linearly related to parathyroid gland size in the uremic animals and associated with rising plasma phosphate levels. In the last study acidosis led directly to increased bone resorption but small parathyroid glands associated with elevated ionized calcium levels. Alkalosis lowered the serum ionized calcium and led to parathyroid enlargement and the expected associated findings. It was shown that parathyroid weight reflected both metabolic activity as judged by amino acid uptake, and the content of immunoassayable parathyroid hormone. In all studies gland weight was inversely related to serum ionized calcium.

Animals↗