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Biomedical subjects

B Coevoet

Publications and source records attributed to B Coevoet.

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

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↗
PubMed1983

[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↗
PubMed1983

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↗
PubMed1983

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↗
PubMed1983

[Blood gas and acid-base changes and rhythmologic tolerance of acetate and bicarbonate hemodialysis using a standard dialyser with high sodium and control of ultrafiltration].

In order to demonstrate a possible superiority of bicarbonate dialysis (HDB) over acetate dialysis (HDA) in conditions of standard dialysis (4 hours on a 1 m2 cuprophan dialyser) but with a bath rich in sodium (143 mEq/l) and control of ultrafiltration, we have compared 2 sequences of 3 runs of HDA and HDB with these conditions in 8 patients as regards their acido-basic and cardiologic parameters (continuous monitoring of ECG by Holter, regular measurement of blood pressure). Acid base balance study in AHD led to the distinction of 2 groups according to wether their plasma bicarbonate increased or decreased during the run. Rythmological tolerance was the same in BHD and AHD, wether all patients or both groups were considered. Heart rate was however slightly but significantly higher during AHD than during BHD, in the patients whose plasma bicarbonate decreased. In conclusion, the benefit of HDB is not remarkable when HDA is performed not only in standard conditions but also with a bath rich in sodium and with control of ultrafiltration.

Acetates↗
PubMed1982

Renin angiotensin aldosterone system and adrenergic system in normotensive and hypertensive pregnancy.

We have measured simultaneously plasma renin activity (PRA), aldosterone and catecholamines in the plasma of 3 groups of pregnant women after the 20th week: group 1 of 16 normotensive controls, group II of 17 women with rest responding hypertension (RRH), group III of 18 women with permanent hypertension (PIH). All the patients were ambulatory on a normal salt diet. PRA was significantly higher in the RRH than in the control and PIH groups (15,8 +/- 2,3ng/ml/l versus 6,7 +/- 0,5 and 8,9 +/- 0,9 respectively). Plasma epinephrine (PE) and norepinephrine (PNE) were significantly higher in the PIH than in the control and RRH groups (respectively 135 +/- 28 pg/ml versus 56 +/- 13 and 63 +/- 17 for PE and 387 +/- 91 versus 206 +/- 32 and 200 +/- 47 pg/ml for PNE). In the PIH group there was a negative correlation between PRA and blood uric acid. It is concluded that the adrenic system is activated in PIH whereas the renin angiotensin system is activated in RRH of pregnancy.

Adult↗
PubMed1982

[Treatment of peritonitis in continuous ambulatory peritoneal dialysis ].

UNLABELLED: Thirty patients were treated with continuous ambulatory peritoneal dialysis during 313 patients months. 26 episodes of peritonitis defined by a cloudy dialysate with more than 100 cells/mm1 and more than 50 p. cent of polynuclear were observed. The organisms initially responsible were Gram-positive in 11 cases (6 Staphylococcus aureus, 1 Staphylococcus albus, 4 Streptococcus viridans), a gram negative in 3 cases (1 Klebsiella, 1 serratio, one unidentified), a Candida in 2 cases. In 10 cases, the culture was negative, Initial treatment was peritoneal lavage (40 l/day) with in situ antibiotics: in the absence of Candida, the association sulfamethoxazole (SMZ) (80 mg/l) and trimethoprim (TMP) (16 mg/l) was used; when Candida was present amphotericin B (5 mg/l) was used. The association SMZ + TMP led to cure of PT in 17 cases, in 7 +/- 4 days. In 5 cases, this initial treatment was changed at the 48th hour because of initial resistance in one case or secondary resistance of Candida surinfection (2 cases). Candida surinfection occurred later in 2 other cases. For these 6 primary or secondary Candida peritonitis, the catheter was changed within 48 hours. Nevertheless, death occurred in 3 cases and cure was obtained after 51 +/- 11 days in the 3 other cases. CONCLUSIONS: 1) The initial treatment by SMZ + TMP appears quite effective in most cases (73%). 2) The severity and the high incidence of Candida surinfection suggest that its systematic prophylaxis may be appropriate.

Adult↗
PubMed1982

[The renin-angiotensin-aldosterone system and the adrenergic system in normal pregnancy and hypertension induced by pregnancy].

Plasma renin activity (PRA), plasma aldosterone (PA) and plasma catecholamines were measured in 3 groups of women with pregnancy of 20-38 weeks: group I of 16 normotensive controls, group II of 17 women with rest responding hypertension (RRH) and group III of 18 women with permanent hypertension (PH) (supine blood pressure greater than 140-90 mmHg after 8 days of rest, disappearing after delivery). Studies were realized on fasting ambulatory women on a normal salt diet. PRA (mean +/- SEM) was significantly higher in the RRH group than in the control and PH groups (15,8 +/- 2,3 ng/ml/h versus 6,7 +/- 0,5 and 8,9 +/- 0,9). PA was higher but not significantly in the RRH group (736 +/- 122 versus 533 +/- 52 and 502 +/- 103 pg/ml). Plasma epinephrine (PE) and norepinephrine (PNE) were significantly higher in the PH than in the control and RRH groups. 135 +/- 28 pg/nl versus 56 +/- 13 and 63 +/- 17 for PE and 387 +/- 91 versus 206 +/- 32 and 200 +/- 47 pg/ml). These data suggest that PH is linked with activation of the adrenergic system whereas RRH is linked with activation of the RAA system.

Aldosterone↗
PubMed1981

Lack of antagonism in the antihypertensive effects of clonidine and prazosin in man.

1. In four patients, whose hypertension was not controlled (supine blood pressure greater than 150--90 mmHg) by addition of 5 mg/day of prazosin to previous treatment (diuretics and beta-blockers), clonidine (150--450 microgram/day) led to control of hypertension in three cases. 2. In ten patients whose hypertension was not controlled by a treatment including clonidine (300--450 microgram/day), the progressive addition of prazosin to a maximal dose of 4--22.5 mg/day led to control of hypertension in nine cases (mean supine blood pressure decreased from 174--102 to 144--88 mmHg). 3. In 13 hospitalized patients, clonidine was abruptly interrupted whereas prazosin was continued. Mean blood pressure (+/- SEM) rose from 145 +/- 1/85 +/- 2 to 169 +/- 7/104 +/- 5 mmHg 48 h after clonidine withdrawal whereas plasma noradrenaline and adrenaline rose from 328 to 758 pg/ml and from 75 to 137 pg/ml. No subjective symptoms were noted. There was a negative correlation between blood pressure increase and the dose of prazosin. 4. It is concluded that (a) there is no antagonism between clonidine and prazosin in their antihypertensive action in man when used at usual clinical doses, (b) a protective effect of prazosin against an eventual clonidine withdrawal syndrome is suggested by the negative correlation between blood pressure increase and the dose of prazosin.

Adult↗
PubMed1981

Blockers of beta and H2 receptors and secondary hyperparathyroidism in uraemia.

The suppressive effect on PTH secretion of propranolol, a beta 1 and beta 2 blocker, and that of atenolol a specific beta 1 betablocker was compared in 24 uraemic patients not yet on dialysis in a cross over study. Although plasma PTH concentrations were comparable, plasma bicarbonate was higher with propranolol suggesting that the initial suppression of PTH secretion by propranolol was greater as a higher bicarbonate should lead to lower ionised calcium. The suppressive effect of cimetidine on PTH secretion was assessed in 12 patients on chronic haemodialysis. In the seven compliant patients there was no change in N and C terminal plasma PTH values but plasma calcitonin concentrations significantly decreased with cimetidine and returned to initial values after cimetidine was discontinued.

Adult↗
PubMed1980

Effect of propranolol and metoprolol on parathyroid hormone and calcitonin secretions in uraemic patients.

Nine uraemic patients not being treated by dialysis received intravenous propranolol 1 microgram/kg/min for 85 minutes after a priming dose of 1 mg. Fifteen days later, six of them received intravenous metoprolol 1.2 microgram/kg/min after a priming dose of 1.2 mg. Plasma concentrations of parathyroid hormone (PTH) and calcitonin fell significantly after propranolol but not after metoprolol, whereas no change in plasma concentrations of ionised calcium and phosphate occurred with either drug. Heart rate fell similarly with both drugs. The fact that propranolol acutely suppressed PTH and calcitonin secretion in uraemic patients indicates that further studies are warranted to assess the long-term effects of the drug on the secretion of these hormones and on renal osteodystrophy. The contrast between the responses to propranolol and metoprolol supports the concept that PTH and calcitonin secretion is modulated through specific beta 2-receptors.

Adult↗
PubMed1980

[Evidence, in uremic man, of the role of beta 2 adrenergic receptors in the secretion of parathyroid hormone and calcitonin (author's transl)].

In order to determine the effect of beta-blocking agents on secretions of parathyroid hormone and calcitonin, 9 patients with renal failure were given single doses of propranolol (a blocker of the beta 1 and beta 2 receptors) or an equivalent amount of metoprolol (a beta 1 selective agent). Propranolol causes a decrease of plasma parathyroid hormone (p less than 0.02) as well as of calcitonin (p less than 0.05) whereas metoprolol has no effect on the plasma levels of these hormones. These findings suggest that parathyroid tissue and thyroid C cells have receptors that are exclusively of the beta 2 type which are modulating the secretion of parathyroid hormone and calcitonin.

Adult↗