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Biomedical subjects

J L Sebert

Publications and source records attributed to J L Sebert.

At least 73 records · Page 4Linked to original sources
PubMed1987

Plasma bone Gla-protein: assessment of its clinical value as an index of bone formation in hemodialyzed patients.

Plasma bone-Gla protein was measured in 27 non-selected patients on chronic hemodialysis or hemofiltration with no overt radiological bone disease. Individual values ranged from normal to 10-times the upper limit of the normal range. Plasma bone-Gla protein correlated with the histomorphometric parameters of bone turnover and bone formation and with plasma parathyroïd hormone and alkaline phosphatase. When patients were classified according to their Bone Formation Rate, plasma bone-Gla-protein allowed a better distinction between high and low bone formation rates than did alkaline phosphatase or plasma parathyroïd hormone.

Adult↗
PubMed1986

Effect of thyrotoxicosis and its treatment on mineral and bone metabolism.

Mineral metabolism and bone histomorphometric status were evaluated in 31 hyperthyroid patients (HT) without clinical or radiological bone disease, both before and after treatment of hyperthyroidism. Blood and urine biochemical data were compared with those obtained in sex and age-matched controls. Iliac bone biopsies were available from 12 untreated HT and from 6 of them after treatment for analysis of trabecular bone. Mean plasma calcium was increased in HT but true hypercalcemia was seen in only one case and mean plasma immunoreactive parathormone (iPTH) was normal. Urine calcium excretion was markedly increased, especially in the fasting state. Biochemical parameters decreased after treatment, except for serum alkaline phosphatase and iPTH that, respectively, remained high and increased. Untreated state was characterized by an hyperremodelling state with enhanced activities of bone formation and bone resorption. Bone mineralization was normal. The mineral and bone changes were related to serum thyroid hormone levels. After treatment, the extent of formation surfaces still increased. The fact that, even though calcium metabolism abnormalities were corrected, active resorption surfaces did not change, suggests that trabecular osteoclastic resorption is not an important cause of mobilization of bone calcium to extracellular fluids in HT.

Adult↗
PubMed1986

Comparative evaluation of bone aluminum content and bone histology in patients on chronic hemodialysis and hemofiltration.

In order to compare hemofiltration (HF) and hemodialysis (HD) in connection with the risk of aluminum overload and renal osteodystrophy, double bone biopsies after double tetracycline labeling and a desferrioxamine test were performed in 12 patients on HF and 15 patients on HD. The aluminum concentration was low (less than 0.6 mumol/l) both in the dialysate and the substitution fluid. The duration of treatment (about 2 years) and the cumulative doses of Al(OH)3 and CaCO3 were comparable in the two groups. None of the patients was taking 1 alpha-OH-D. The aluminum balance during an HF run ranged from -22 to +1.8 mumol/l, the balance being positive only when the plasma aluminum was less than 0.5 mumol/l. Basal plasma aluminum and its increase induced by desferrioxamine were comparable in the two groups. Bone aluminum content was also comparable, but was about 10 times higher than in 7 nonuremic controls. Bone aluminum content and plasma aluminum increase after desferrioxamine were correlated to the Al(OH)3 cumulative dose. None of the patients had florid osteomalacia with increased osteoid thickness, and only 1 in each group had traces of stainable aluminum. The mineralization front was decreased in 8 of 12 HF and in 9 of 14 HD patients, so that no difference was observed between the means of the two groups. The predominant histological bone picture of the patients was osteitis fibrosa which was present in 10 of 12 HF and in 13 of 15 HD patients. Mean osteoclast count and active resorption surface were comparable in the two groups, but was increased (5-10 times the mean of the controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Phospho-calcium and bone metabolism in hyperthyroidism in adults].

The abnormalities of calcium-phosphorum metabolism observed in hyperthyroidism (tendency to hypercalcaemia with subsequent functional hypoparathyroidism, increase in serum alkaline phosphatase and in hydroxyprolinuria) essentially result from excessive mobilization of bone calcium and phosphates by the thyroid hormones themselves. Histomorphometric studies have shown that the skeletal repercussions of hyperthyroidism are almost constant. There is, in particular, excessive bone remodelling due to increased bone-forming and bone-resorbing cellular activities. However, since bone resorption is quantitatively more stimulated than bone formation, the physiological bone loss is accelerated and is only partly repaired by re-establishment of the normal thyroid function.

Bone Diseases↗
PubMed1985

Comparison of 1 alpha-OH-vitamin D3 and high doses of calcium carbonate for the control of hyperparathyroidism and hyperaluminemia in patients on maintenance dialysis.

27 patients on hemodialysis (dialysate aluminium less than 0.7 mumol/l for 2 years, and 2 mumol/l before) whose plasma Ca and PO4 were adequately controlled for already 6 months by high doses of CaCO3 alone (mean +/- SD: 9 +/- 5 g/day), were randomly divided into 2 groups, a control group (c group) which was kept on the same treatment, and a group in which CaCO3 was reduced to 3 g/day but in which plasma Ca was kept normal due to 1 alpha-OH-vitamin D3 administration (1 microgram/day at the beginning, 0.3 microgram/day after 6 months; 1 alpha group) whereas plasma phosphate was kept below 6.0 mg/dl because of Al(OH)3 (2.7-5 g/day). Initially, the 2 groups were comparable as regards the plasma concentrations of total and ionized Ca, phosphate, alkaline phosphatases, medium and C-terminal parathyroid hormone (PTH) and aluminium, but the control group had lower plasma 25-OH-vitamin D (25-OHD.) After 6 months, the same difference in plasma 25-OHD was found with comparable plasma concentrations of total and ionized calcium as well as of medium and C-terminal PTH (beta error 1%). However, plasma concentration of phosphate and the plasma Ca phosphate product, as well as the plasma aluminium were higher in the 1 alpha group whereas their PCO3H- was lower. Although the alkaline phosphatase values were not significantly different between the 2 groups, they increased only in the control group because of 1 patient who developed a vitamin-D-deficient osteomalacia (plasma 25-OHD 3 ng/ml), which was subsequently cured by physiological doses of 25-OHD3. The incidence of transient hypercalcemia (15 vs. 21 episodes) and worsening of soft tissue calcifications (3 in each group) was the same in the 2 groups.

Adult↗