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Biomedical subjects

G Heynen

Publications and source records attributed to G Heynen.

At least 37 records · Page 2Linked to original sources
PubMed1983

Piroxicam suppositories for osteoarthritis and rheumatoid arthritis: an open multicentre study in 116 patients.

Efficacy and toleration of piroxicam suppositories 20 mg, given once daily for 4 weeks were assessed in 96 patients suffering from degenerative joint disease and 20 patients suffering from rheumatoid arthritis. The mean scores of objective parameters measured (tenderness, swelling, limitation of movement) decreased significantly 2 and 4 weeks after initiation of therapy. Patients' self-evaluation of pain and stiffness also significantly improved during the trial. Overall evaluation of efficacy and toleration were excellent or good in more than 80% of patients. Local toleration was excellent in all but two patients.

Adult↗
PubMed1983

Calcium metabolism and hyperparathyroidism after renal transplantation.

Plasma calcium and albumin levels were measured serially in 100 patients for two years following successful renal transplantation. Mean plasma calcium increased during the first six months after grafting, in large part attributable to an increase in plasma albumin. The variance around the mean plasma calcium did not increase suggesting that mechanisms responsible for hypercalcaemia were common to the majority of patients. 36 per cent of patients developed hypercalcaemia within two years of grafting but the incidence fell to 11 per cent when more rigorous criteria for hypercalcaemia were used. The mechanisms maintaining plasma calcium were studied in 29 of the patients, nine of whom were hypercalcaemic and 20 of whom were normocalcaemic. Before transplantation, mean plasma calcium and phosphate levels were higher, the prevalence of subperiosteal erosions and extraskeletal calcification radiographically was greater, and the duration of haemodialysis treatment was longer in the hypercalcaemic patients than in the normocalcaemic recipients. At assessment after transplantation, hypercalcaemic patients had lower levels of plasma phosphate, higher plasma levels of alkaline phosphatase and parathyroid hormone, and higher hydroxyproline excretion. Renal function and 47Ca absorption were similar in the two groups. The major cause for apparent hypercalcaemia in transplanted patients appeared to be an increase in plasma albumin. In patients with true hypercalcaemia the major cause was pre-existing hyperparathyroidism where hypercalcaemia was mediated by increased renal tubular reabsorption of calcium.

Calcium↗
PubMed1982

An estimate of the endogenous secretion rate of calcitonin in man.

1. The metabolic clearance rate (MCR) of human calcitonin was measured in 12 normal subjects and four patients with Paget's disease by the infusion of synthetic human calcitonin (15-40 microgram/h for 2-24 h), and in 10 additional patients with Paget's disease from the disappearance rate of immunoreactive calcitonin from plasma after the intravenous injection of large doses of synthetic human calcitonin (0.5-1.0 mg). 2. The estimated MCR during the infusion studies (range 531-1224 litres/day) was similar to that calculated from the disappearance of large doses of synthetic human calcitonin injected intravenously in patients with Paget's disease (mean = 1035 litres/day; range = 593-1408 litres/day). 3. An eightfold range in the basal values of plasma immunoreactive calcitonin, in spite of the presence of a relatively constant MCR, suggests that the variation in basal plasma calcitonin was due principally to variation in the endogenous secretion rate for calcitonin. 4. The results suggest that the endogenous secretion rate for calcitonin is low in normal subjects (mean 124 +/- SEM 24 microgram/day), and give a basis for selecting the doses of calcitonin which can be considered physiological.

Adolescent↗
PubMed1982

Deterioration of renal bone disease in patients treated with salmon calcitonin.

Twelve patients with chronic renal failure and osteitis fibrosa were treated for periods of 1-9 months with thrice-weekly injections of 10-200 iu salmon calcitonin. Treatment had no significant effects on symptoms of bone disease and side effects were common. A transient fall in plasma alkaline phosphatase levels occurred in only three patients, and both plasma alkaline phosphatase and hydroxyproline levels rose in the majority of patients. Radiographic signs of hyperparathyroidism increased in seven of the nine patients treated for longer than 3 months. Paired bone biopsy specimens in nine patients showed significant increases in osteoblast counts, but no changes in the indices of resorption. These treatment-induced changes were reversed when treatment with 1,25-dihydroxyvitamin D3 was substituted for calcitonin. The use of this regimen of salmon calcitonin is not recommended in the long-term management of hyperparathyroid bone disease in chronic renal failure.

Adult↗
PubMed1981

Cimetidine-induced PTH variations in uraemic patients evaluated with the aid of antisera against the terminal carboxyl and amino groups of the hormone molecule.

Eight uraemic patients on periodic haemodialysis were given 600 mg of cimetidine every day for 15 days. Parathyroid hormone levels before and at the end of this treatment were evaluated with two different antisera specific against the terminal -COOH and -NH2 groups of the hormone respectively. The results obtained suggest two things: though cimetidine may enhance PTH secretion, at the same time it accelerates peripheral disintegration of some of its metabolically active metabolites. It i therefore necessary to reconsider the possible use of cimetidine in the treatment of hyperparathyroidism associated with uraemia.

Adult↗
PubMed1981

Responses to salmon calcitonin in chronic renal failure: relation to histological and biochemical indices of bone turnover.

Twenty-one patients with chronic renal failure and bone disease or hypercalcaemia were studied before and following single (twenty patients) or repeated (fourteen patients) intravenous injection of synthetic salmon calcitonin. Significant correlations were noted before treatment between bone surfaces occupied by osteoblasts or osteoclasts and plasma levels of immunoreactive parathyroid hormone, alkaline phosphatase and hydroxyproline. Following a single injection of 2--200 i.u. salmon calcitonin, plasma levels of calcium and phosphate fell for 6--8 h, but rose subsequently to pre-injection levels at 24 h. The magnitude and duration of the hypocalcaemic response was not clearly dose-dependent, but correlated with measured indices of bone cell activity. Repeated administration of calcitonin (10--200 i.u. thrice weekly for up to 2 months) lowered plasma calcium in the majority of patients and restored plasma calcium to normal in four previously hypercalcaemic patients. Mean levels of alkaline phosphatase increased but no significant changes in plasma phosphate, immunoreactive parathyroid hormone and calcitonin, or hydroxyproline occurred. Calcium absorption (six studies) did not change during treatment. We conclude that synthetic salmon calcitonin is an effective short-term inhibitor of bone resorption in patients with chronic renal failure. Its use as a possible treatment for hypercalcaemia and hyperparathyroid bone disease in chronic renal failure is discussed.

Adult↗
PubMed1981

Lack of clinical and physiological relationship between gastrin and calcitonin in man.

The clinical and physiological relevance of the relationship between gastrin and calcitonin has been investigated in normal subjects and in patients suffering from gastritis or duodenal ulcer. Basal plasma levels of calcitonin are increased in these patients but there is no significant relationship between calcitonin and gastrin levels. Acute pentagastrin injection in normal male subjects increased significantly (P less than 0.05) plasma calcitonin levels whereas lower doses of pentagastrin which are known to stimulate gastric secretion are without effect on calcitonin levels. Moreover, stimulation of gastrin secretion by a protein test meal and by intragastric administration of a calcium chloride solution is not followed by any significant increase of plasma calcitonin levels. These results suggest that the stimulation of calcitonin secretion by gastrin and its synthetic analogue pentagastrin is a pharmacological rather than a physiological phenomenon.

Adult↗
PubMed1981

Suppressive effects of 24,25-dihydroxycholecalciferol on bone resorption induced by acute bilateral nephrectomy in rats.

The possible suppressive effects of 24,25-dihydroxycholecalciferol on secondary hyperparathyroidism and increased bone resorption were investigated in adult rats raised on a diet normal in calcium, phosphorus, and vitamin D, and subjected to acute bilateral nephrectomy. The animals had received subcutaneous radiocalcium 4 wk before the experiment. 5 h after nephrectomy an increase in serum total calcium, (45)Ca-specific activity, citrate, phosphorus, and magnesium concentrations were observed. Serum immunoreactive parathyroid hormone increased, while serum calcitonin decreased. The osteoclast count in the tibial metaphyses was augmented. The biochemical and histological changes observed were partly parathyroid hormone and calcitonin independent, as they also occurred in parathyroidectomized hypocalcemic rats. Pretreatment with 650 pmol of 24,25-dihydroxycholecalciferol 16 h before nephrectomy prevented bone calcium mobilization and diminished the rise in serum total calcium and citrate both in parathyroid-intact and in parathyroidectomized animals. In parathyroid-intact rats, serum immunoreactive parathyroid hormone and calcitonin remained normal in spite of the fall in serum-ionized calcium, and the number of osteoclasts did not increase. In parathyroidectomized rats, 24,25-dihydroxycholecalciferol did not prevent the postnephrectomy rise in the osteoclast count. This latter observation suggests that this metabolite exerts its effect on bone either by acting on cells other than osteoclasts, i.e., the osteocytes, or by inhibiting cell activity. At equimolar dosage 1,25-dihydroxycholecalciferol had a potent stimulatory effect on bone resorption. This effect of 1,25-dihydroxycholecalciferol was partly blocked by the simultaneous administration of 24,25-dihydroxycholecalciferol. The potential clinical significance of these observations remains to be determined.

24,25-Dihydroxyvitamin D 3↗
PubMed1981

Comparison of acute effects of 1.25- and 24.25-dihydroxy-vitamin D3 in normal subjects.

Effects of small iv doses of 1.25-dihydroxy- and 24.25-dihydroxy-vitamin D3 (a microgram) were studied in 10 normal subjects. Injection of 1.25 (OH)2D3 was associated with small but significant increases in plasma calcium and phosphate but plasma levels of immunoreactive parathyroid hormone (iPTH) and calcitonin (iCT) did not change. The administration of 24.25 (OH)2D3 was associated with comparable decreases in plasma calcium and a small and transient decrease in plasma iPTH. Plasma levels of iCT did not change. 24.25 (OH)2D3 also significantly increased glomerular filtration rate and decreased the urinary excretion of noradrenaline, in contrast to 1.25 (OH)2D3 which had no effect on these variables. The rapid infusion of calcium significantly decreased levels of iPTH. We conclude that small doses of 1.25 (OH)2D3 and 24.25 (OH)2D3 have little, if any, direct effect on the secretion of PTH and CT in man.

24,25-Dihydroxyvitamin D 3↗
PubMed1981

[Radioimmunoassay for type II amino-terminal procollagen peptide. Technical note].

We have studied the immunoreactivity of human sera and synovial fluids in a radioimmunoassay which utilizes an anti-bovine procollagen type III antiserum and the bovine type III procollagen peptide as standard and tracer. We have noticed a complete cross reaction between bovine col 1-3 and human synovial fluid, which thus contains substance (s) having the same antigenic determinant (s) as col 1-3. On the contrary, we have demonstrated non parallelism between col 1-3 and human serum, whether the serum was obtained from normal subjects or patients suffering from various diseases. These results suggest that immunoreactive substances related to col 1-3 and detected in sera are at least partially different from those detected in synovial fluids.

Animals↗
PubMed1981

[Specificity of human proteoglycan radioimmunoassay].

The human articular cartilaginous proteoglycans (PG) R.I.A. is highly specific. The PG used as the standard and the 125I labelled molecule appear to be pure. Under these conditions, all the potential interfering substances which have been tested show no cross reaction. For instance, the Ag-Ab equilibrium is not affected by adding human IgG, human albumin, hyaluronic acid, chondroitin sulfate, rat type II collagen or total human serum proteins. This R.I.A. also exhibits a species specificity since there is no cross reaction with rat PG and negligible cross reaction with dog PG. The results obtained after addition of enzymes to the antigen demonstrate that the antigenic sites are localized on the protein region and not on the glycosaminoglycan region of the molecule.

Animals↗
PubMed1980

An evaluation of 1 alpha-hydroxy-and 1,25-dihydroxyvitamin D3 in the treatment of renal bone disease.

40 patients with bone disease due to chronic renal failure have been treated with 1 alpha-hydroxyvitamin D3 or 1,25-dihydroxyvitamin D3 for a total of 750 patient-months. Both compounds were very effective in relieving bone pain and muscle weakness, and in reversing the radiographic and biochemical indices of disturbed skeletal metabolism. Their effects as judged from bone biopsies were, however, less complete, and histological improvement occurred only in a few patients. Patients with the combination of osteitis fibrosa and osteomalacia responded better than patients with either abnormality alone. Factors of importance in adversely influencing the outcome of treatment included a high pre-treatment level of calcium or immunoreactive parathyroid hormone, and a failure to augment secretion of calcitonin during treatment. It is concluded that a major therapeutic advantage of 1 alpha-OHD3 and 1,25(OH)2D3 over previously available forms of vitamin D is their rapid onset and reversal of action. These drugs do not invariably reverse bone disease and may give rise to unwanted effects. They should therefore only be used with adequate clinical, biochemical and radiographic supervision. They should not be used indiscriminately in all renal patients.

Adolescent↗