Anabolic actions of parathyroid hormone on bone.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
M Parisien
Publications and source records attributed to M Parisien.
Maintenance of cancellous bone connectivity in primary hyperparathyroidism: trabecular strut analysis.
We previously demonstrated an increase in cancellous bone volume and trabecular number in patients with mild primary hyperparathyroidism (PHPT). To test the hypothesis that this increase is due to preservation of cancellous bone architecture, we conducted a trabecular strut analysis using a new method that measures trabecular connectivity. Iliac crest biopsies from 37 patients with PHPT, 14 men (28-68 years) and 23 women (26-68 years), were examined histomorphometrically and compared to cadaveric samples from 24 age-matched subjects, 17 men and 7 women. Two-dimensional indices of cancellous structure--node number (N.Nd), terminus number (N.Tm), node to node (Nd.Nd), node to terminus (Nd.Tm), and terminus to terminus (Tm.Tm) strut lengths, and total strut length (TSL)--were measured and the ratio of node number to terminus number (N.Nd/N.Tm) calculated. TSL, N.Nd, and Nd.Nd were significantly higher in patients than in controls. TSL and Nd.Nd, but not N.Nd or Nd/Tm, decreased significantly with age in PHPT, indicating that age-related bone loss in PHPT occurs without significant loss of trabecular connectivity. Two-dimensional indices reflecting connectivity or the amount of bone, that is, N.Nd, Nd.Nd, N.Nd/N.Tm, and TSL, correlated positively with cancellous bone volume (BV/TV) and trabecular number (Tb.N) and negatively with trabecular spacing (Tb.Sp) in both PHPT and controls. Trabecular thickness (Tb.Th) correlated positively with Nd.Nd and Tb.N and negatively with Tm.Tm in PHPT but not in controls. The present data show that in PHPT there is not only greater cancellous bone volume and trabecular number but preserved trabecular connectivity as well. The data further support the hypothesis that in PHPT cancellous bone architecture is maintained.
Adult↗
Characterization and evaluation of asymptomatic primary hyperparathyroidism.
Data are presented on 97 patients with primary hyperparathyroidism who constitute a representative cohort of the disease seen today. The average calcium (11.1 +/- 0.1 mg/dl; normal 8.7-10.7), phosphorus (2.8 +/- 0.1 mg/dl; normal 2.5-4.5), and parathyroid hormone level by immunoradiometric assay (119 +/- 7 pg/ml; normal 10-65) are typical of the modern presentation of primary hyperparathyroidism. Most patients were asymptomatic in that there was evidence for nephrolithiasis in only 18% and for radiologically evident bone disease in only 1% of patients. Nevertheless, when patients were evaluated with bone densitometry and with histomorphometric analysis of the bone biopsy specimen, evidence for the hyperparathyroid process could be shown in the majority of patients. Selective reduction of cortical bone and preservation of cancellous bone were apparent. Among patients with nephrolithiasis, no particular feature distinguished them from patients without nephrolithiasis. All biochemical data were similar between both stone and non-stone formers. The selective reduction in cortical bone was seen to the same extent among those with stones as among those without stones. The average 1,25-dihydroxyvitamin D level was not increased among those with stones. When the population was divided into groups with elevated or normal 1,25-dihydroxyvitamin D levels, the incidence of nephrolithiasis was unchanged. The results indicate that bone involvement can be demonstrated among most patients with asymptomatic primary hyperparathyroidism and that no pathophysiologic mechanisms are yet apparent to account for nephrolithiasis in primary hyperparathyroidism.
Adult↗
The histomorphometry of bone in primary hyperparathyroidism: preservation of cancellous bone structure.
To evaluate the effects of primary hyperparathyroidism (PHPT) on bone mass and structure, we have studied the iliac crest biopsies of 27 patients, 10 males (28-68 yr old) and 17 females (26-72 yr old) with mild PHPT after in vivo tetracycline labeling. All patients had mild hypercalcemia in the absence of any other cause and elevated levels of PTH without radiological evidence of bone disease. Static parameters of bone turnover (osteoid surface, osteoid volume, and eroded surface) were elevated in both men and women compared to normal values; the midmolecule RIA for PTH (PTHMM) was positively correlated with osteoid surface (r = 0.44; P less than 0.025) and eroded surface (r = 0.58; P less than 0.005). Dynamic parameters of bone turnover (mineralizing surface, expressed as double plus half single labeled surface, and bone formation rate at tissue level) were elevated compared to normal values; PTHMM was positively correlated with double plus half single labeled surfaces (r = 0.33; P less than 0.05) and with bone formation rate at the tissue level (r = 0.37; P less than 0.05). The mineral apposition rate was within the limits of normal values and positively correlated with PTHMM (r = 0.34; P less than 0.05). Histomorphometric parameters of bone structure [cancellous bone volume (BV/TV), trabecular thickness (Tb. Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), cortical thickness (Ct.Th), and total bone density (TBD)] were compared to those in 20 autopsy control subjects, 12 men (33-60 yr old) and 8 women (27-75 yr old). BV/TV and Tb.N were significantly higher in PHPT patients than controls (P less than 0.02 and P less than 0.001, respectively). Tb.Sp was significantly lower in PHPT patients than controls (P less than 0.001), whereas Tb.Th was not significantly different between PHPT patients and controls. Ct.Th was significantly lower in PHPT patients than in controls (P less than 0.001), whereas TBD was not significantly different between the two groups. BV/TV was negatively correlated with age in both controls and PHPT patients. Tb.N showed a negative correlation and Tb.Sp a positive correlation with age in controls (r = -0.47; P less than 0.05 and r = 0.52; P less than 0.02, respectively), but they were not significantly dependent on age in PHPT patients. Tb.Th, while showing no significant age-related change in controls, was negatively correlated with age in PHPT patients (r = -0.42; P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)
Adult↗
Bone disease in primary hyperparathyroidism.
The classic bone disease of primary hyperparathyroidism, osteitis fibrosa cystica, was characterized by subperiosteal bone resorption, osteopenia, and "brown tumors." Since the description of this skeletal disorder, the clinical profile of primary hyperparathyroidism has evolved markedly. The disease today is often characterized by no more than asymptomatic hypercalcemia, and severe bone disease is a distinct rarity. However, as we have endeavored to show in this article, newer and more sensitive techniques show significant evidence of the effect of excess parathyroid hormone on the skeleton. Bone density as measured by photon absorptiometry and bone histomorphometry show a deficit of cortical bone and a preservation or increase in cancellous bone elements in mild primary hyperparathyroidism with no clinical evidence of skeletal disease. Important questions exist as to the therapeutic implications of these data. Does the presence of parathyroid hormone effect on sophisticated testing portend the development of clinical bone disease? Should these data be used as a rationale for surgical intervention in patients who might otherwise be followed conservatively with mild primary hyperparathyroidism? The answers to these questions must await further data collection and study.
Bone Diseases↗
Evidence for a toxic effect of aluminum on osteoblasts: a histomorphometric study in hemodialysis patients with aplastic bone disease.
To evaluate the potential role of aluminum (Al) in a subset of dialysis patients with aplastic bone disease, we have studied tetracycline-labeled bone biopsies of 32 patients (22 males and 10 females, 45-73 years) on maintenance hemodialysis. Selection criteria included normal resorption surfaces (RS) and osteoid thickness. Eleven patients (Group I) had no stainable bone Al (Al-; 61.7 +/- 7.2 years) and 21 (Group II) had stainable bone Al (Al+; 57.7 +/- 6.8 years). Serum Al was normal to slightly elevated in Group I, but significantly higher in Group II (p less than 0.01). Al surfaces (AlS), undetectable in Group I, were 67.8 +/- 17.9% in Group II. Bone Al content (BAC) was much lower in Group I than in Group II (14.8 +/- 3.7 vs. 113.8 +/- 100.2 micrograms/g, p less than 0.01), but higher in Group I than in controls (p less than 0.05). Extensive thin osteoid seams were present in Group II. AlS was correlated with OS (r = 0.56, p less than 0.001) and OV (r = 0.48, p less than 0.01). Labeled surfaces were decreased in both groups. Labeled osteoid surfaces (TLS/OS) were below 2 SD of the mean control values in 96% of patients and calcification rate (CR) was depressed below 0.20 micros/day in 44% of patients. Bone formation rate (BFR) was strikingly depressed, values being below one SD of the mean control value in 92-100% of patients at both levels and below 2 SD of the mean in 82% of patients at BMU levels. Mineralization lag time (OMP) was markedly prolonged above 2 SD of controls in 89% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Deferoxamine-induced bone changes in haemodialysis patients: a histomorphometric study.
1. The histological effects of deferoxamine therapy were assessed on transiliac bone biopsies taken after double tetracycline labelling from 16 uraemic patients undergoing chronic haemodialysis, all having aluminium deposits in bone. Eight patients had osteomalacia, five had an "aplastic" bone lesion and three a high bone turnover with a marked increase in osteoid volume. 2. Deferoxamine was administered intravenously once a week at doses ranging from 1 to 6 g for a mean duration of 7.6 +/- 3.3 (SD) months. 3. Deferoxamine therapy was associated with significant reductions in stainable aluminium deposits, osteoid volume, osteoid surfaces and thickness index of osteoid seams. The osteoblastic osteoid surfaces as well as the bone formation rates also increased significantly. 4. A rise in resorption parameters and in serum parathyroid hormone levels was observed in patients with osteomalacia. The percentage reductions in stainable aluminium and in osteoid volume were correlated with the degree of hyperparathyroidism. 5. These data show that deferoxamine therapy reduces stainable bone aluminium and improves bone mineralization in low turnover osteomalacia and that the presence of hyperparathyroidism is associated with an increased response to deferoxamine therapy.
Adult↗
Dysplasia epiphysealis hemimelica of the scapula. A case report.
Explore the source record for details and available documents.
Adolescent↗