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Biomedical subjects

B Coevoet

Publications and source records attributed to B Coevoet.

At least 19 recordsLinked to original sources

[Epidemiology of primary glomerulonephritis in Picardie].

Between 1 January 1976 and 31 December 1986, primary glomerulonephritis was histologically diagnosed in 319 patients, living in a region of 675,000 inhabitants at the time of renal biopsy. The prevalence of primary glomerulopathy was 0.4/1000 inhabitants. The annual incidence was determined during two 5 year periods: period A (1976-1980) and period B (1981-1985): they were, respectively, 3.4 and 4.5 for 100,000 inhabitants. Berger's focal glomerulonephritis was the most common (30 p. 100) and its incidence was increasing. In contrast, membranoproliferative and acute glomerulonephritides were sharply decreased (almost disappeared), while membranous glomerulonephropathies and glomerulopathies with minimal glomerular lesions or proliferative forms with crescents increased. All primary glomerulonephritides were more prevalent in men and their frequencies increased with age. Our findings lead to the following conclusions: a) the low prevalence and incidence of primary glomerulopathies (3 times less than in other published studies) probably reflect the under medicalization of our region and the attractiveness of neighbouring metropolis, rather than a real decrease in the disease; b) the quasi- disappearance of acute and membranoproliferative glomerulonephropathies and the high incidence of IgA glomerulonephropathies suggest that their pathogenetic associations with infections sensitive to antibiotics are different; c) the increased frequency of membranous glomerulonephropathy and the glomerulopathy with minimal glomerular lesions in aged subjects is most likely due to their polymedication.

Adult

Hemodialysis in the treatment of lactic acidosis in diabetics treated by metformin: a study of metformin elimination.

The aim of this study was to determine the characteristics of metformin elimination by dialysis. For this purpose we report the kinetic parameters during dialysis and the metformin clearance (i.e. dialysance) in four patients presenting with lactic acidosis which occurred on metformin therapy. We also studied metformin elimination in two chronically hemodialyzed diabetic patients inadvertently maintained on metformin therapy and in two chronically hemodialyzed non-diabetic patients who took a single dose of metformin before a dialysis session. Analysis of plasma concentration-time curves showed a biphasic pattern of metformin - elimination, according to a two-compartment model. We demonstrate that metformin may be removed even after reaching an equilibrium between blood and dialysate levels in a recirculating system, suggesting a storage of metformin in a deep compartment with a gradient of concentration between this compartment and the blood. Lastly, metformin dialysance appears satisfactory (68 ml/min) even in the case of relatively low blood flow; this value reached 170 ml/min under good hemodynamic conditions. In conclusion, hemodialysis efficiently removes metformin and corrects metabolic acidosis in patients with metformin-induced lactic acidosis.

Acidosis, Lactic

Indirect clinical evidence that 1 alpha OH vitamin D3 increases the intestinal absorption of aluminum.

In a previous study we showed that 1 alpha OH vitamin D3 [1 alpha (OH)3] given to 16 hemodialyzed patients taking Al(OH)3 at a constant dose increased their plasma concentrations of aluminum [Demontis et al. 1986]. In order to choose between 2 possible mechanisms explaining this increase (increased intestinal absorption or decreased tissue storage of aluminum), we gave, in the present study, 1 alpha (OH)3 the same dose (6 micrograms per week) for the same period (4 weeks) to 15 stable hemodialyzed patients after their Al(OH)3 had been discontinued for 6 weeks. Under Al(OH)3 treatment they had a mean plasma aluminum (2.33 +/- 2.36 mumol/l) which was not significantly different from that of the patients in our former study (1.23 +/- 0.25 mumol/l). After Al(OH)3 discontinuation, plasma aluminum (measured by inductively coupled plasma emission spectrometry) decreased significantly as early as the 2nd week of the control period (1.39 mumol/l). The decrease was maintained at a plateau throughout the 5 weeks of the control period (1.38 mumol/l), the 4 weeks of 1 alpha OH vitamin (vit) D3 administration (1.40 mumol/l) and the 8 weeks of the post 1 alpha (OH)3 period (1.22 mumol/l). Plasma calcium and phosphate concentrations increased significantly with 1 alpha (OH)3 and decreased thereafter whereas plasma PTH concentrations decreased during 1 alpha (OH)2 D3 and increased after its discontinuation suggesting biological activity of 1 alpha (OH)3. Since 1 alpha (OH)3 increases plasma aluminum in hemodialyzed patients only when they are simultaneously taking Al(OH)3, it is suggested that this increase is explained by an increase of intestinal absorption of aluminum and not by a tissue redistribution of aluminum.

Adolescent

[Indirect evaluation of the effect of 1 alpha-hydroxyvitamin D3 on intestinal absorption of aluminum].

In a former study we have shown that 1 alpha OH vitamin D3 given to hemodialyzed patients taking A1(OH)3 at a constant dose increased their plasma concentrations of aluminium. Two mechanisms can explain this increase: increased intestinal absorption or decreased tissue storage of aluminium. We have, in the present study, given 1 alpha(OH)3 at the same dose (6 micrograms per week) and during the same duration (4 weeks) to 15 stable hemodialyzed patients after aluminium hydroxide has been discontinued 6 weeks before. Under A1(OH)3 treatment mean plasma aluminium was 2.33 +/- 2.36 mumol/l. After A1(OH)3 discontinuation, plasma aluminium decreased significantly as soon as the 2nd week of the control period (1.39 mumol/l). The decrease was maintained in plateau throughout the 5 weeks of the control period (1.38 mumol/l and, the 4 weeks of 1 OH Vit D3 administration (1.40 mumol/l). After 1 alpha OH D3 discontinuation there has been a non significant transient drop of aluminemia followed by a plateau at a level comparable to the previous plateau. Plasma calcium and phosphate concentrations increased significantly with 1 alpha(OH)3 and decreased thereafter confirming biological activity of 1 alpha(OH)3. Since 1 alpha(OH)3 increases plasma aluminium in hemodialyzed patients only when they are taking simultaneously A1(OH)3, it is suggested that this increase is mainly explained by an increase of the intestinal absorption of aluminium.

Adult

Bicarbonate haemodialysis: an adequate treatment for lactic acidosis in diabetics treated by metformin.

Lactic acidosis in diabetics on metformin therapy is rare but still associated with poor prognosis. The authors report here five cases. Three patients were initially with a cardiovascular collapse and all had an acute renal failure. Sodium bicarbonate haemodialysis therapy led to a dramatic improvement. Consciousness and hemodynamic status recovered rapidly. Severe metabolic and blood gases derangements were also rapidly corrected. Plasma metformin removal, appreciated by repeated blood samplings in 3 cases, was satisfactory. All patients survived. However, blood metformin levels remained abnormally high at the end of the dialytic therapy. In conclusion, (1) bicarbonate dialysis is an adequate treatment of lactic acidosis observed in diabetic patients treated with metformin since it rapidly corrects the acid-base disorders and partially removes metformin; (2) the sole accumulation of metformin is not sufficient to explain lactic acidosis since this latter might be corrected in spite of persisting high levels of blood metformin.

Acidosis, Lactic

[Acute renal insufficiency caused by observed a combination of enalapril, furosemide and flurbiprofen in a patient with retroperitoneal fibrosis].

The case of vasomotor parenchymal acute renal failure is reported in a patient a few days after the initiation of treatment by Enalapril which is a new converting enzyme inhibitor. No renal artery stenosis could be demonstrated, which is in contrast with the numerous cases reported up to now. However the helping roles of an incomplete obstruction by a peri-aneurysmal retroperitoneal sclerosis, of prolonged anterior treatment with flurbiprofen and of simultaneous administration of furosemide may be discussed.

Acute Kidney Injury

Critical role of oxalate restriction in association with calcium restriction to decrease the probability of being a stone former: insufficient effect in idiopathic hypercalciuria.

The probability of being a stone former (PSF) was calculated in 3 groups of idiopathic calcium stone formers [with normocalciuria (NC), dietary hypercalciuria (DH) and idiopathic hypercalciuria (IH)] in 4 conditions: while on a free diet; on a calcium- and oxalate-restricted diet during 4 days; after an oxalate load, while on a 1.5-gram calcium diet, and after an oxalate load while on a calcium-restricted diet. Combined calcium and oxalate restriction significantly decreased PSF only in NC and DH whereas the decrease was not significant in IH because of a concomitant significant increase in oxalate excretion. Increase of PSF with the oxalate load was significantly greater during a calcium-restricted diet than during the 1.5-gram calcium diet in all groups of patients (4, 6 and 12 times greater in NC, DH and IH, respectively). These data show the critical role of oxalate restriction when calcium is restricted in order to decrease the PSF. This combined restriction is however not sufficient in idiopathic hypercalciuric patients to decrease their PSF.

Calcium

Plasma renin activity, blood uric acid and plasma volume in pregnancy-induced hypertension.

UNLABELLED: Plasma renin activity (PRA), plasma aldosterone (PA), blood uric acid (BUA), plasma concentrations of catecholamines (Pcat) and plasma volume (PV) were measured simultaneously in 24 patients with pregnancy-induced hypertension. This hypertensive group was divided into labile (LH) and permanent hypertension (PH) groups according to the response of their blood pressure to home bed rest. As compared to normal theoretical values, PV was decreased in both hypertensive groups (LH = -70%; PH = -14%). As compared to a control group of 16 normotensive pregnant women, PRA was higher in LH and lower in PH whereas PA was lower in both hypertensive groups. In both hypertensive groups, BUA was higher than in the control group. No difference in Pcat was found between the three groups. In the PH group negative correlations were found between BUA and PRA, as well as between BUA and PV, but no correlation between PRA and PV nor between Pcat and BUA were found. CONCLUSIONS: LH and PH are two pathophysiologically different entities in pregnancy-induced hypertension. In PH, renin secretion is not appropriate to hypovolemia and therefore not primarily involved in the pathogenesis of hypertension. The role of hypovolemia in the increase of BUA may be discussed.

Female

Effect of calcium restriction on renal excretion of oxalate and the probability of stones in the various pathophysiological groups with calcium stones.

To evaluate the adequacy of simple calcium restriction for patients with idiopathic calcium stones the effect of 5 days of calcium restriction without oxalate restriction on renal excretion of calcium and oxalate, and the corresponding probability of stones were assessed in 50 controls and 48 patients. Renal excretion of calcium decreased and that of oxalate increased significantly in all groups but the importance of the changes was critically dependent upon the underlying pathophysiological condition. The probability of stones decreased only in patients with absorptive hypercalciuria type II owing to the usual excessive calcium intake and increased in those with absorptive hypercalciuria type I and renal hypercalciuria, which are associated with true hyperabsorption of calcium and represent the 2 forms of idiopathic hypercalciuria. We believe that simple calcium restriction is beneficial for patients with idiopathic calculi only when the hypercalciuria is caused by exaggerated intake of calcium, since it increases the probability of stones in patients with idiopathic hypercalciuria. Calcium restriction always is associated with an increase in oxalate excretion, suggesting that simultaneous oxalate restriction should be added in all cases to decrease the probability of stones.

Adult

[Treatment of peritonitis in peritoneal dialysis. Comparison between continuous lavage with a machine and intermittent lavage with 4 CAPD bags/day].

Since 1978, 54 episodes of PT occurred in patients treated by PD, first 26 PT (group A) were treated by CLM (40 l/day) and in situ antibiotics (AB): in the absence of Candida, the association of sulfamethoxazol (SMZ: 80 mg/l) and trimethoprime (TMP: 16 mg/l) was used. Only when a Candida was present amphotericine B (AMB: 5 mg/l) was used. CLM was continued until PT was cured. The last 29 PT (group B) were treated by 4 bags/day of CAPD with in situ AB: SMZ: 200 mg/l and TMP 40 mg/l and a systematic oral prophylaxis of Candida was performed by AMB 1,5 g/day. In group A, 5 patients died and 2 others in group B. Complications were more frequent in group A (14) than in group B (6): p less than 0.02. In group A, the AB was changed in 7 cases because of initial resistance (1) or bacterial superinfection (2) or Candida superinfection (4). In group B, AB was changed in 9 cases because of initial resistance (7) or Candida superinfection (2). In conclusion the treatment of PT by 4 bags per day with in situ AB cure PT as rapidly as CLM in spite of lower doses of SMZ - TMP. However, this method is easier to perform and give less complication than CLM. It must be the treatment of choice of PT from peritoneal dialysis.

Anti-Bacterial Agents

Plasma renin activity, blood uric acid and plasma volume in pregnancy-induced hypertension.

UNLABELLED: Plasma renin activity (PRA), plasma aldosterone (PA), blood uric acid (BUA), plasma concentrations of catecholamines (Pcat) and plasma volume (PV) were measured simultaneously in 24 patients with pregnancy-induced hypertension (PIH). This hypertensive group was divided into labile (LH) and persistent hypertension (PH) groups according to the response of their blood pressure to home bed rest. Compared to normal theoretical values, PV was decreased in both hypertensive groups (LH = -7%; PH = -14%). Compared to a control group (C) of 16 normotensive pregnant women, PRA was higher in LH and lower in PH whereas PA was lower in both hypertensive groups. BUA was higher than in C in both hypertensive groups. No difference in PCat was found between the three groups. In the PH group negative correlations were found between BUA and PRA, as well as between BUA and PV but no correlation between PRA and PV nor between Pcat and BUA were found. IN CONCLUSION: LH and PH are two pathophysiologically different entities in PIH. In PH renin secretion is not appropriate to hypovolaemia and therefore not primarily involved in the pathogenesis of hypertension. Hypovolaemia may play a role in the increase of BUA in PIH.

Adult

Critical role of oxalate restriction in association with calcium restriction to decrease the probability of being a stone former: insufficient effect in idiopathic hypercalciuria.

The probability of being a stone former (PSF) was calculated according to the method of Robertson in three groups of idiopathic calcium stone formers (normocalciuria (NCa), dietary hypercalciuria (DH) and idiopathic hypercalciuria (IH] during four conditions: on a free diet; on a calcium and oxalate restricted diet for four days and after an oxalate load (200 g of spinach) while on a calcium unrestricted or calcium restricted diet. Combined calciuria (Ca) and oxaluria (Ox) restriction significantly decreased PSF only in NCa and DH whereas the decrease was not significant in IH because of a concomitant significant increase in oxalate excretion. Increase of PSF with the oxalate load was significantly greater on calcium restricted than on calcium unrestricted diets in all groups of patients (4-6-12 times greater in NCa, DH and IH respectively). This shows the critical role of oxalate restriction when calcium is restricted in order to decrease the PSF. Combined restriction is not sufficient in idiopathic hypercalciuric patients to decrease their probability of stone formation.

Calcium