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Biomedical subjects

M Labeeuw

Publications and source records attributed to M Labeeuw.

At least 73 records · Page 4Linked to original sources
PubMed1984

[Diagnosis of relative hypomagnesurea in calcium lithiasis: reference values for a new parameter].

In calcium stone formers, the ratio of urinary magnesium concentration to urinary calcium concentration (Mg/Ca) is used to express the already reported low Mg excretion relatively to Ca excretion. However the Mg/Ca value depends on the Ca excretion rate, decreases after oral Ca load and is not directly related to Mg excretion. Therefore when studying patients with different Ca excretion rates, or when performing an oral Ca load, Mg/Ca is not directly useful to express a relative hypomagnesuria. We established a new parameter from the normal relationship between urinary Mg and Ca excretion rates. Its value is above - .065 in 97.5% of 99 control urinary samples. It is stable for any studied Ca excretion rate, including post Ca load excretion rates, and is highly correlated with Mg excretion rate. This parameter allows for the accurate diagnosis of relative hypomagnesuria in stone formers.

Adult↗
PubMed1983

Ranitidine kinetics in chronic renal impairment.

The effects of moderate to severe renal impairment on kinetics of the H2-blocker ranitidine were investigated in 16 patients divided into two groups. Mean inulin clearance (ClIn) was 35 +/- 18.3 ml/min/1.73 m2 in group I and 7.4 +/- 3.5 ml/min/1.73 m2 in group II. Each patient received a single 150-mg oral dose of ranitidine. Values determined were maximum plasma concentration (MC) and time of occurrence, AUC, elimination t 1/2 (t 1/2 beta), total amount of unchanged ranitidine recovered in urine, and ranitidine renal clearance (ClR). MC values were higher and longer delayed than values reported in subjects with normal renal function. The t 1/2 beta was longer in group I and group II and correlated with the degree of renal impairment. The amount of ranitidine excreted within the first 24 hr decreased (18% of the dose in group I and 6% of the dose in group II), and ClR correlated strongly with ClIn, indicating that the observed changes in ranitidine kinetics are mainly related to changes in its renal excretion.

Adult↗
PubMed1983

[Comparative effects on renal function of 4 beta-blockers injected intravenously].

Four beta-blockers: atenolol 15 mg i.v., metoprolol 25 mg i.v., acebutolol 45 mg i.v. and labetalol 50 mg i.v. were administered to 106 patients suffering from hypertension and with normal or disturbed renal function. During an identical test protocol, measurements of clearance of inulin, of PAH, urine sodium and the fraction of sodium excreted were recorded one hour before and four or five hours after administration of the antihypertensive. Mean blood pressure and heart rate were also recorded. The three pure beta-blockers reduced inulin and PAH clearance and lowered urine sodium. These modifications were the same for all three drugs. Labetalol, which also possesses alpha-blocking properties, did not reduce renal function values or urine sodium. While a slight fall in blood pressure occurred with all the antihypertensives, heart rate was reduced only by the three pure beta-blockers. The action of the four drugs was very similar whatever the state of the subject's renal function. The study of the renal effects of the beta 1-selective atenolol and metoprolol, and acebutolol which has a higher intrinsic sympathomimetic activity does not demonstrate any significantly different renal action among these three drugs, but the effects of labetalol on renal function values and urine sodium are slighter. The renal action of the beta-blockers cannot be fully explained. Though the fall in the renal plasma flow and in the glomerular filtration rate can be related partly to the decrease in the cardiac output consequent to induced bradycardia, stimulation of renal alpha-receptors must be considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1982

The nephrotic syndrome in adults aged over 60: etiology, evolution and treatment of 76 cases.

A study of the clinical, etiological and histological features of the nephrotic syndrome occurring in 76 adults aged over 60 was performed. Membranous nephropathy was the most frequent type (40%). 32% of the cases of membranous nephropathy were associated with another disease which was a malignant one in 22% of the cases. In 2 cases a renal vein thrombosis was associated with the malignant disease. Amyloidosis appeared to be the most frequent cause of the secondary nephrotic syndrome (13%), and was often associated with plasma cell dyscrasia. The study also showed the importance of lipoid nephrosis among elderly patients with the nephrotic syndrome (20%). Amongst these cases it is necessary to consider the association of minimal changes with a systemic disease, and the histological diagnosis of focal hyalinosis. Indeed the presence in elderly patients of arteriolar, interstitial and glomerular lesions of hyalinosclerosis makes interpretation difficult. With corticosteroid therapy complete remission was frequent in patients with lipoid nephrosis.

Age Factors↗
PubMed1981

[Treatment of severe resistant arterial hypertension with captopril. 58 patients, including 38 treated for more than 6 months (author's transl)].

Of 58 patients treated with captopril, 3 have now received the drug for more than 2 years and 22 for more than one year. This study concerns 38 patients treated for 6 months, captopril having been given alone during the first 2 months. They all had severe hypertension (diastolic BP Greater Than 110 mmHg) which had resisted previous treatments in normally effective doses, including at least one beta-blocker, dihydralazine and a diuretic. After 6 months blood pressure levels were normal in 53% of the patients, reduced in 31% and unchanged in 16%. Clinical improvement was habitual with, in particular, disappearance or decrease of tiredness and dyspnoea. Since some side-effects of the drug, such as granulopenia, proteinuria and ageusia, are mainly observed with high dosage, captopril is usually administered in doses lower or equal to 400 mg/day. In resistant or malignant hypertension it must be used in combination with salt-free diet, a beta-blocker and/or prazosin. Clinical, haematological and renal surveillance is necessary during treatment. When these precautions are observed, captopril constitutes a very useful drug for the treatment of patients with severe resistant hypertension.

Adult↗
PubMed1981

Cystine crystalluria and urinary saturation in cystine and non-cystine stone formers.

It has been suggested recently that the first step in the formation of calcium oxalate stones appears to be crystallisation. This step is said to depend on the state of saturation of the urine. This hypothesis was checked in cystine stone formers. Cystine crystalluria was found in 83% of 24 urine samples from cystine stone formers (CSF) but in one of the 400 control samples and appears to be a good guide in the diagnosis of cystine lithiasis. Urinary cystine saturation was constantly higher in CSF than in non-cystine stone formers (NCSF) who exhibited undersaturated urine with respect to cystine. There was almost no overlap between these 2 groups. Crystals were never found in undersaturated urine and were always present when the saturation was above 1. There appears to be a good correlation between the level of urinary saturation and the presence of crystalluria and there is no need for any additional factor such as a defective inhibitor. The study underlines the limits of a therapeutic regimen of a high fluid intake and alkalinisation of the urine.

Crystallization↗
PubMed1981

Acute effect of high dose (48 mg) of piretanide in advanced renal insufficiency.

1 The acute effects of a high dose of piretanide, a new potent diuretic were studied in eight patients with severely impaired renal function (GFR between 0.09 and 0.17 ml s-1 1.73 m-2). 2 After hydration and following two control periods, a single dose of 48 mg piretanide was ingested. Thereafter, urine was collected every 30 min for 2 h and every hour for the next 4 h. Urinary fluid losses were replaced orally (100 ml of water ever hour) and intravenously (isotonic saline + glucose infusion). 3 The following measurements were made: urine flow rate, clearances of inulin, PAH, urea, creatinine, uric acid, osmolar and free water clearances, excretion rates of sodium, chloride, potassium, calcium, phosphate, bicarbonate, ammonium, titratable acidity and urine pH. 4 Piretanide (48 mg) appeared to be effective in advanced renal insufficiency, producing a significant increase in urine flow rate, in sodium, chloride, potassium and calcium excretion and in Cosm. 5 There was no significant change in GFR, as measured by inulin clearance, or in the other measured parameters.

Adult↗
PubMed1980

Uric acid, monosodium urate and ammonium urate urinary relative saturations in normo-uricuric calcium oxalate stone formers.

Monosodium urate (NaU), ammonium urate (NH4U) and uric acid (UA) urinary relative saturations were studied in 15 normo-uricuric calcium oxalate (CaOx) recurrent stone formers whose CaOx relative saturation was identical to age- and sex-matched controls. NaU and NH4U relative saturations were constantly below 1 and not higher in stone formers than in controls, suggesting that heterogeneous nucleation is an unlikely mechanism of CaOx stone formation in vivo. Such values of NaU relative saturation would also tend to rule out any change in the CaOx formation product or urinary inhibitory activity. However, at a given urinary flow rate, NaU relative saturation was suggestively higher in stone formers than in controls. Some disturbance in the equilibrium between NaU and urinary inhibitors might then exist even in normo-uricuric CaOx stone formers.

Animals↗
PubMed1979

Nephrotic syndrome in procainamide induced lupus nephritis.

We report a case of the nephrotic syndrome occurring in a patient with procainamide induced LE. It was associated with bilateral pleural effusions, pericarditis, fever, positive LE cell preparation and a high titer of antinuclear antibodies. No anti-DNA antibodies were found. Renal biopsy showed mesangial proliferation with few IgM and C3 deposits and interstitial infiltrates; electron microscopy revealed subendothelial deposits. Clinical improvement occured after steroid therapy and there was no recurrence 24 months after withdrawal of prednisone.

Aged↗
PubMed1976

Acute renal effects of new beta-adrenergic receptor site blocking agents on renal function.

The effects of two new beta blockers on renal function have been studied. There were significant decreases in urine flow, urea clearance, sodium and chloride excretion rates after acute administration. Fractional excretion of sodium (FeNa) fell significantly but did not continue to fall during chronic administration. Blood pressure and plasma renin activity decreased significantly after two months' therapy. These findings suggest that beta blockers in patients with unstable cardiovascular function increase the need for concomitant diuretic therapy.

Acebutolol↗