Biomedical subjects

C Morieux

Publications and source records attributed to C Morieux.

24 records · Page 2Linked to original sources

PubMed1989

Deferoxamine test and bone disease in dialysis patients with mild aluminum accumulation.

Aluminum bone disease is a frequent complication of dialysis patients. The deferoxamine (DFO) test has been advocated as a noninvasive procedure for the diagnosis of AI bone lesion. However most of these studies have been performed in symptomatic patients with significant AI bone disease. Whether this test may provide similar data at an earlier stage of AI toxicity is not known. The present study evaluates prospectively 28 patients with mild AI load. Patients studied ranged in age from 21 to 65 years; duration of dialysis was 5.6 +/- 3.2 years; deferoxamine, 40 mg/kg body weight, was infused at the end of dialysis. Serum AI was measured before DFO administration and before the next dialysis treatment. Bone biopsies were performed in all patients. Cortical bone AI was determined biochemically; trabecular and cortical bone AI were also determined histochemically. Mean basal serum AI (43.2 +/- 30.8 micrograms/L) and cortical bone AI (25.7 +/- 35.2 micrograms/g) were moderately increased. Basal serum AI correlated (r = 0.77) with the increment in serum AI after DFO infusion. After DFO, stainable trabecular and cortical bone AI correlated in a similar manner with both basal serum AI and increment in serum AI. Only biochemically determined cortical bone AI was not significantly related to basal serum AI. Nineteen of the 28 patients had evidence of osteitis fibrosa on bone biopsy. Stained AI surfaces but not trabecular AI were different in patients with low and patients with high bone formation rates. The bone findings, assessed as bone formation rates and resorption surfaces, did not correlate with biochemically or histochemically determined bone AI.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗

PubMed1989

Optimal correction of acidosis changes progression of dialysis osteodystrophy.

To investigate an eventual role of acidosis on hemodialysis osteodystrophy we prospectively studied 21 patients who were dialyzed with different amounts of bicarbonate in the dialysate for 18 months. According to the level of bone formation rate (BFR) on a prestudy bone biopsy, patients were split in two subgroups. Inside these two subgroups patients were randomly allocated to two therapeutics groups: 10 patients (group A) were dialyzed with the conventional amount of bicarbonate (33 +/- 2 mmol/liter) in the dialysate; the rest of the patients (group B, N = 11) had 7 to 15 mmol/liter sodium bicarbonate added to the dialysate to obtain 24 mEq predialysis bicarbonate plasma levels. An effective correction of acidosis was shown in group B by a higher predialysis plasma bicarbonate level (15.6 +/- 1 group A vs. 24.0 +/- 0.6 mEq/liter group B, P less than 0.005), which was reached three months after start of the study. Compared to the prestudy bone biopsy, osteoid and osteoblastic surfaces increased in group A but not in group B on the bone biopsies performed at the end of the study. Parathormone plasma level (iPTH), measured with an antiserum which cross reacts with the 44-68 region of PTH molecule, increased during the study in group A but not in group B. This finding suggested progression of secondary hyperparathyroidism (HPT) only in group A patients. Osteocalcin plasma values increased in both groups during the 18 months of the study. Consequently the two subgroups of patients formed on the basis of BFR level were evaluated separately.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗

PubMed1989

Relationships between histomorphometric features of bone formation and bone cell characteristics in vitro in renal osteodystrophy.

To determine whether abnormal bone cell recruitment or differentiation may be involved in the development of aplastic bone lesion in renal osteodystrophy we have compared histomorphometric parameters of bone formation and in vitro behavior of osteoblastic cells isolated from the trabecular bone surfaces in 37 dialysis patients with osteitis fibrosa, normal bone formation rate, or aplastic bone lesion. The bone cell responses to human PTH-(1-34) (20 nmol/L), as evaluated by intracellular cAMP production, and to 1,25-dihydroxyvitamin D (10 nmol/L), as assessed by osteocalcin synthesis, were not different from normal in patients with low, normal, or high bone formation rates. Osteoblastic cells isolated from patients with a high bone formation rate and markedly elevated serum iPTH and osteocalcin values had a higher than normal DNA replication in primary culture. The peak of [3H]thymidine incorporation, the maximal DNA synthesis, and the area under the growth curve were 4.4- to 6.3-fold increased in osteitis fibrosa compared to those in normal bone cells obtained from age-matched individuals. By contrast, [3H]thymidine incorporation in bone cells from aplastic patients was about 25% of normal and only 5% of the value in osteitis fibrosa. The decreased DNA replication of cultured bone cells in aplastic patients was unrelated to trabecular bone aluminum staining, but was associated with low serum immunoreactive PTH values compared to those in other groups of patients. These results show that high bone formation in uremic osteoitis fibrosa is associated with higher than normal [3H]thymidine incorporation in bone cells in vitro, whereas low bone formation in aplastic patients results from lower than normal DNA replication and suggest that the defective osteoblastic recruitment in aplastic patients may be related to factors other than aluminum, including inappropriate PTH secretion.

Biopsy↗

PubMed1987

Different schedules of administration of (3 amino-1-hydroxypropylidene)-1, 1 bisphosphonate induce different changes in pig bone remodeling.

Intermittent administration of antiosteoclastic agents has been proposed in order to increase trabecular bone volume (TBV). We evaluated the effect of two different intermittent schedules of administration of (3 amino-1-hydroxypropylidene)-1, 1 bisphosphonate (AHPrBP) on pig bone remodeling for a period of 60 days. AHPrBP (1.6 mumol/kg/injection) was given subcutaneously daily (group A1), or 5 consecutive days out of 21 days (group A2), or 1 out of every fourth day (group A3). Compared to control animals, group A1 significantly increased trabecular bone volume (TBV) (+62%) with a marked decrease in bone resorption assessed by interstitial bone thickness. Bone formation assessed by mean wall thickness (MWT) was also decreased due to a decrease in the number and activity of osteoblasts. There was not a delay in the coupling mechanism as assessed by the reversal surfaces. The two groups receiving intermittent schedules had markedly different results. Group A2 had very similar changes to group A1 despite receiving four time less drug. Compared to group A1 and A2, group A3 had smaller decrease in resorption and higher bone formation rate with identical MWT. These differences between group A2 and A3 were associated with similar levels of parathyroid hormone and vitamin D metabolites. Different bone concentrations induced by the two different schedules of AHPrBP may explain the greater effect on bone resorption and osteoblast recruitment in group A2 and thus a milder effect of the AHPrBP administration once every fourth day.

Animals↗

PubMed1985

Increased bone aluminum deposition after subtotal parathyroidectomy in dialyzed patients.

Ten dialyzed patients underwent a systematic bone biopsy before and 19 +/- 9 months after subtotal parathyroidectomy (PTX). At the end of the follow-up period all the patients, except two, who complained of proximal myalgia, were asymptomatic. Compared to the bone biopsy specimen obtained prior surgery, decreased bone formation without mineralization impairment was observed after PTX. Despite an average decrease in aluminum gels intake after PTX, an increase in stained aluminum was observed (0.69 +/- 0.79 versus 1.20 +/- 0.95 mm/mm2, P less than 0.050). Aluminum accumulation depended on the pre-PTX bone aluminum load: pre- and post-PTX bone aluminum loads were correlated (r = 0.78, P less than 0.01). Bone aluminum accumulation was not related to the amount of aluminum gel intake after PTX; however, only two patients free of both bone aluminum deposit prior to PTX and aluminum gel intake after PTX had no stainable aluminum on the second bone biopsy after PTX. The only patient who had no decrease in bone formation after PTX had no increase in bone aluminum. Assuming that the patients had no aluminum deposit prior to dialysis, we measured the rate of bone aluminum accumulation. It rose from 0.11 +/- 0.09 mm/mm2/year prior to PTX to 0.40 +/- 0.25 mm/mm2/year after PTX (P less than 0.05) in the six patients who were maintained on phosphate binders and who had a decrease in bone formation after PTX. These six patients had unchanged aluminum gel intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1984

Effects of iron overload on bone remodeling in pigs.

For study of the effects of an iron overload on bone remodeling, 5 control pigs were compared with 5 pigs given a total dose of 10.8 g of parenteral iron in 36 days. Treated pigs developed an iron tissue overload demonstrated by a marked increase in bone and liver iron. Except for a modest increase in SGOT, there was no biochemical or histologic sign of liver damage. Serum levels of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were unchanged in the treated pigs. There was no accumulation of iron in the parathyroid glands and the serum immunoreactive parathyroid hormone level was unchanged in the treated animals. Bone histomorphometry after double tetracycline labeling showed that in the treated pigs osteoblast cell surfaces, double and total labeled surfaces, appositional rate, and formation at tissue level were significantly decreased, and reversal surfaces were increased. Mineralization was not impaired because the osteoid thickness was unchanged. From the morphometric measurements it was concluded that osteoblast recruitment and the collagen synthesis rate were decreased. Mean wall thickness, which indicates the amount of bone synthesized, was also lowered. In contrast, the osteoclastic resorption surfaces and the depth of lacunae resulting from osteoclast resorption were unchanged by treatment. Despite this imbalance between formation and resorption, trabecular bone mass estimated on trabecular bone volume and bone ash was unchanged after 36 days' treatment. Perls' stain revealed that iron deposits were present in osteoblast and osteoclast cells and also inside the bone matrix, because there was a linear deposit along the trabecular surfaces, cement line, and osteoid-mineralized bone interface. Therefore, because treatment induced no modification of the major humoral regulators of bone metabolism, it is suggested that iron, which was present in bone cells and matrix, could play a role in bone remodeling.

Alanine Transaminase↗