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Biomedical subjects

H Favre

Publications and source records attributed to H Favre.

At least 55 records · Page 3Linked to original sources
PubMed1993

Natriuretic and vasoactive hormones and glomerular hyperfiltration in hyperglycaemic type 2 diabetic patients: effect of insulin treatment.

Evidence that an increase in plasma atrial natriuretic peptide (ANP) concentrations mediates, at least in part, glomerular hyperfiltration in diabetic rats prompted us to study the relationship between ANP and renal haemodynamics in hyperfiltering type 2 diabetic patients in association with other hormones implicated in the control of glomerular filtration rate (GFR) (catecholamines, vasopressin, renin) and in sodium tubular transport (aldosterone, ouabain-displacing factor, ODF). Since hyperglycaemia is also associated to hyperfiltration, diabetic patients who presented with secondary drug failure were studied both in hyperglycaemic and in normoglycaemic condition. For this purpose, 11 normotensive non-macroproteinuric hyperfiltering patients with type 2 diabetes were treated with an 8-day continuous insulin infusion (days 0-7). Dehydration was prevented or corrected and natriuresis was on day 0 above 100 mmol/day. The following parameters were determined on days 0 and 7: GFR and renal plasma flow (RPF) by 99mTc-DTPA and 131I-hippuran clearances; the extracellular volume, assimilated to the DTPA diffusion volume; urinary ODF by receptor-binding assay and urinary as well as plasma catecholamines by HPLC after extraction on alumin. Plasma ANP and antidiuretic hormone (ADH) were measured by radioimmunoassay after extraction on phenyl-silylsilica (ANP) and with ether (ADH). Unextracted plasma was used for radioimmunological measurement of plasma renin activity and aldosterone. When correcting hyperglycaemia to normoglycaemia GFR decreased from high to normal mean value (138 +/- 27 and 115 +/- 6 ml/min, p < 0.001), RPF followed the same trend, and the DTPA diffusion volume did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Mechanism of enhanced Na-K-ATPase activity in cortical collecting duct from rats with nephrotic syndrome.

The maximal hydrolytic activity of Na-K-ATPase is specifically increased in the cortical collecting duct (CCD) of rats with puromycin-induced nephrotic syndrome (NS). This stimulation is independent of aldosterone and of endogenous ouabain-like substance. To investigate the mechanism responsible for this change, we compared the maximal Na-K-ATPase hydrolytic activity, the ouabain sensitive 86Rb influx, the specific [3H]ouabain binding, and the sensitivity of Na-K-ATPase to ouabain in the CCD of control rats and of rats given an intraperitoneal injection of puromycin 7 d before study. Both Na-K-ATPase activity and ouabain-sensitive 86Rb influx increased two-fold in rats with NS (ATPase activity: 34.1 +/- 2.1 vs. 18.0 +/- 0.7 pmol.mm-1 x min-1 +/- SE, n = 6, P < 0.001; Rb influx: 14.4 +/- 0.7 vs. 7.4 +/- 0.4 peq.min-1 +/- SE, n = 6, P < 0.001) whereas specific [3H]ouabain binding decreased in rats with NS (6.9 +/- 0.7 vs. 9.0 +/- 0.6 fmol.mm-1 +/- SE, n = 6, P < 0.005). Therefore, the maximal turnover rate of Na-K-ATPase increased over twofold in rats with NS (5,053 +/- 361 vs. 2,043 +/- 124 cycles.min-1 +/- SE, n = 6, P < 0.001). Analysis of the curves of inhibition of Na-K-ATPase by ouabain showed the presence of two Na-K-ATPase populations in both control and NS rats: a highly sensitive population (apparent Ki: 1.4 x 10(-6) M and 0.9 x 10(-6) M) and a less sensitive moiety (apparent Ki: 2.6 x 10(-4) M and 1.1 x 10(-4) M). The enhancement of Na-K-ATPase activity observed in the CCD of rats with NS was entirely due to the stimulation of the population of Na-K-ATPase with low ouabain sensitivity. These results suggest that a dysregulation of this subclass of Na-K-ATPase might be the primary cause of sodium retention in this model of nephrotic syndrome.

Animals↗
PubMed1993

[What is the practical attitude toward isolated microscopic hematuria?].

Practical attitude towards isolated microscopic hematuria. The finding of isolated asymptomatic microhematuria usually raises questions about the need to perform further, invasive investigations. Phase contrast microscopy of the urine sediment is a sensitive, noninvasive method that provides information on the glomerular or non glomerular origin of hematuria, as well as on its grade. This analysis, however, must be performed by an experienced technician under standard conditions. The presence of dysmorphic (i.e. glomerular) erythrocytes indicates a glomerular disease if the count is higher than 10 erythrocytes per microliter but is considered physiological if the count is below this number. In these two cases, no further investigation will be undertaken if all criteria for isolated microhematuria are verified. Conversely, isomorphic erythrocytes reveal a non glomerular origin of hematuria, which may indicate a serious urological disease. In this case, further investigations (e.g. ultrasound, urine cytology) are recommended, taking into account the age of the patient.

Erythrocyte Count↗
PubMed1992

Sites of antinatriuretic action of insulin along rat nephron.

This study was aimed at identifying the renal sites of the antinatriuretic action of insulin by evaluating whether this hormone may alter the function of Na-K-ATPase in specific nephron segments. For this purpose, possible actions of insulin on the rate of 86Rb uptake were evaluated in vitro on single segments of proximal convoluted tubule (PCT), thick ascending limb, and collecting tubule microdissected from collagenase-treated kidneys of normal rats. Results indicate that physiological concentrations of insulin inhibited by 44% the initial rate of ouabain-sensitive 86Rb uptake in the medullary and cortical thick ascending limb, whereas it increased it by 40% in proximal tubules and by 60% in both cortical and medullary collecting tubules. The kinetics and dose dependence of insulin actions were different in the thick ascending limb, the PCT, and the collecting tubule, with the latter less sensitive but displaying an earlier response to insulin than the PCT and the thick ascending limb.

Animals↗
PubMed1991

High-dose intravenous IgG treatment and renal function.

In an open trial of high dose intravenous IgG (IVIG) treatment in nephrotic patients with glomerulonephritis, the first six patients so far studied showed a transient rise in plasma creatinine. This increase was not associated with any symptoms and the urinary deposit remained unchanged. Two other patients with pre-existing renal impairment but without nephrotic syndrome had a transient and reversible rise in plasma creatinine immediately after IVIG. These observations suggest that high-dose IVIG infusion can produce short-lived disturbances in renal function in patients with kidney diseases.

Adult↗
PubMed1991

Na+,K(+)-ATPase activity and hormones in single nephron segments from nephrotic rats.

1. In the nephrotic syndrome the kidneys retain salt and water, which leads to oedema formation. The site of this sodium retention has been localized in the cortical collecting tubule by micropuncture studies. Whether or not this phenomenon is an intrinsic renal problem or is the consequence of changes in hormonal activities is still a matter of discussion. 2. Using the model of puromycin aminonucleoside-induced nephrotic syndrome in the rat, we measured Na+,K(+)-ATPase activity in nephron segments from control and nephrotic rats and investigated the regulatory role of aldosterone and endogenous-ouabain-displacing factor. 3. Nephrotic animals had a twofold increase in Na+,K(+)-ATPase activity in the cortical collecting tubule only (control versus nephrotic: 1065 +/- 68 versus 2081 +/- 274 pmol h-1 mm-1, P = 0.036), which was not modified by adrenalectomy and was independent of the kidney content of endogenous ouabain-displacing factor. Na+,K(+)-ATPase activity in the cortical collecting tubule correlated with the sodium balance in both control and nephrotic rats. 4. The data are consistent with the view that sodium retention in this model of the nephrotic syndrome is a primary event, i.e. an increase in sodium transport throughout the cortical collecting tubule expressed as a twofold increase in Na+,K(+)-ATPase activity which is no longer under hormonal regulation (aldosterone and endogenous ouabain-displacing factor).

Adrenalectomy↗
PubMed1991

Very severe self-poisoning lithium carbonate intoxication causing a myocardial infarction.

A case of severe lithium carbonate self-poisoning is described, presenting with a very high serum lithium level (14.6 mmol/L) on admission. Lengthy and repeated hemodialyses were required to lower lithemia to nontoxic ranges. As is usually reported, our patient had prolonged neurologic manifestations (coma, hyperreflexia, fluctuating focal signs) and developed hypotension, cardiovascular collapse, nephrogenic diabetes insipidus, and diarrhea. Other less common features were the occurrence of acute myocardial infarction without coronary artery lesions and thrombocytopenia. The possible pathogenic mechanisms are discussed. Hemodialysis and supportive intensive care treatment are commented upon. The final outcome was favorable, and the patient recovered completely.

Bipolar Disorder↗
PubMed1990

Plasma atrial natriuretic factor and urinary excretion of a ouabain displacing factor and dopamine in normotensive pregnant women before and after delivery.

Estimation of urinary excretion of a ouabain displacing factor and dopamine was carried out immediately before delivery, and 7 days and 70 to 90 days after delivery in 12 normotensive pregnant women. Simultaneous estimation of plasma 99-126 atrial natriuretic factor, plasma renin activity, and plasma aldosterone were also undertaken. The data were compared with those obtained in a group of nonpregnant normotensive women (n = 14) and a group of pregnant normotensive women in the early phase of the third trimester (n = 14). Urinary ouabain displacing factor and dopamine levels were significantly higher in the early phase of the third trimester, as compared with nonpregnant women. But immediately before delivery, ouabain displacing factor excretion had fallen below nonpregnant values and dopamine excretion had dropped to control values. Both remained low after delivery. Plasma atrial natriuretic factor was higher in pregnant women, as compared with nonpregnant controls and remained high just before delivery and 7 and 70 to 90 days after delivery. Plasma renin activity and plasma aldosterone levels were higher during pregnancy and had fallen to nonpregnant values 7 days post partum. This drop in plasma renin activity and aldosterone by 7 days post partum, in contrast with the unchanged high values of atrial natriuretic factor, may contribute to negative sodium balance after delivery. It is concluded that there is considerable discrepancy in natriuretic and antinatriuretic factors before and after delivery.

Atrial Natriuretic Factor↗
PubMed1990

Atrial natriuretic factor in patients with congenital heart disease: correlation with hemodynamic variables.

To investigate the alpha-atrial natriuretic factor in congenital cardiac malformations, three groups of children, aged 7 months to 16 years, with different hemodynamic situations were studied during routine cardiac catheterization. Twenty-one (group I) had tetralogy of Fallot, 24 (group II) had a left to right shunt with pulmonary hypertension and 12 (control group) had a minor cardiac lesion. Alpha-atrial natriuretic factor levels were determined by a radioimmunoassay on blood samples from the inferior vena cava, right atrium, pulmonary artery, left atrium and aorta. To evaluate the effect of an acute volume load, measurements of hormone and pressures were repeated after right ventriculography. Alpha-atrial natriuretic factor levels varied over a wide range in all groups and in all chambers investigated. Nevertheless, children with pulmonary hypertension had significantly higher levels of the hormone (p less than 0.01) and were well separated from the control group, but less well from those with tetralogy of Fallot. A 50% increase of alpha-atrial natriuretic factor from the inferior vena cava to the right atrium occurred in patients with shunt lesions with pulmonary hypertension and in patients with tetralogy of Fallot (p less than 0.001) and a further 30% increase from the right atrium to the pulmonary artery (p less than 0.05). After right ventriculography, a 100% to 200% increase of alpha-atrial natriuretic factor was observed in the total sample (p less than 0.001). A positive correlation was observed between right atrial mean pressure and right atrial alpha-atrial natriuretic factor (r = 0.63) and between pulmonary artery mean pressure and pulmonary artery alpha-atrial natriuretic factor (r = 0.61).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Continuous veno-venous hemofiltration in acute renal insufficiency].

A fully pump-assisted continuous veno-venous hemodiafiltration system (CVVHDF) was studied in 10 acute renal failure patients. A counter current pump system ensured slow dialysis at a mean flow rate of 24.6 +/- 0.6 ml/min (single pass) and guaranteed recovery of 97% of dialysate. Ultrafiltration rates were controlled by a separate occlusive pump, connected to the dialysate compartment. Blood was circulated by mean of a third pump at flow rates ranging form 100 to 150 ml/min. Mean duration of CVVHDF was 197 +/- 32 h (range 96-336). Mean serum creatinine and urea before initiation of CVVHDF were 525 +/- 52 mumol/l and 36 +/- 14 mmol/l and stabilized after 4-7 days of CVVHDF at 280 +/- 27 mumol/l and 14 +/- 3 mmol/l. Hemodynamic parameters remained stable. Glucose and phosphate removal by CVVHDF was 296 +/- 42 mmol/day and 33 +/- 6 mmol/day respectively. Fractional losses of aminoacids given by parenteral nutriton averaged 8 +/- 1%. An 69 filters induced no significant changes in leucocyte and thrombocyte counts and only a slight decrease in pO2 (-0.78 +/- 0.30 K Pa at 60 min). We conclude that CVVHDF is a safe, efficient and reliable treatment modality, allowing a good control of the fluid balance.

Acute Kidney Injury↗
PubMed1989

[Indications for renal biopsy].

The cost/benefit ratio of renal biopsy defines the mandatory indications in situations where histologic diagnosis is required for the choice of treatment and for predicting the evolution of renal function. These indications include nephrotic syndrome, permanent proteinuria associated with microhematuria or not, rapidly progressive nephropathies, and, at least in some authors' view, systemic lupus erythematosus. Additional indications should be considered in patients presenting with acute renal failure of unknown origin, renal involvement accompanying systemic diseases, isolated microhematuria and intermittent proteinuria. In these latter indications histology allows the choice of specific therapy in some 20% of cases; the evolution of renal function can be correctly evaluated in 90% of cases. Patients usually consider renal biopsy a benign investigation which helps them to cope with their disease on the basis of a definite diagnosis.

Biopsy, Needle↗
PubMed1989

[Blood pressure values during an exercise test].

High blood pressure readings are relatively frequent during dynamic exercise testing. However, because of the paucity of date concerning normal blood pressure values during exertion and the prognostic significance of exertion hypertension, the attitude to be adopted towards such patients is ill-defined. The present study proposes mean values for BP at a given workload, per age group (less than 20, 20-39, 40-59, greater than 60) and per sex. These values were computed from measurements during dynamic exercise tests performed by 303 subjects (177 male, 126 female) at 100 and 150 watts workloads. Systolic and diastolic pressures during exertion correlated positively with resting blood pressure values (p less than 0.001) and increased with age (p less than 0.001). Hypertension during exertion was defined as values more than 2 SD above mean values for the corresponding age group and sex. 20 subjects met these criteria in our study.

Adaptation, Physiological↗
PubMed1989

Changes in lipoproteins induced by the remnant kidney tissue or binephrectomy in chronic uremic patients treated by hemodialysis.

The role of the remmant kidney tissue in uremic patients undergoing hemodialysis treatment has rarely been considered to influence the changes in lipoprotein and lipid metabolism. Twenty hemodialyzed patients with remnant kidneys and 11 anephric patients were studied to examine whether the presence or the absence of remnant kidney leads to qualitative or quantitative changes of the lipids and lipoproteins. Anephric patients showed a significantly higher triglyceride level, 3.66 +/- 0.49 (SEM) mmol/L v 2.34 +/- 0.09 mmol/L in patients with remnant kidneys (P less than .01), higher very-low-density lipoprotein (VLDL) triglycerides, 1.24 +/- 0.30 mmol/L v 0.69 +/- 0.09 (P less than .04), and higher HDL-triglycerides, 1.22 +/- 0.29 mmol/L v 0.66 +/- 0.09 mmol/L (P less than .04). APO-AI was significantly decreased in anephric patients, 95.2 +/- 13.3 mg/dL v 129.7 +/- 6.02 mg/dL in patients with remnant kidneys (P less than .01). APO-B was similar in both groups. All APO-C and APO-E were significantly lower in anephric patients, APO-CI 6.13 +/- 0.87 mg/dL v 8.47 +/- 0.42 mg/dL in patients with remnant kidneys (P less than .01), APO CII 1.00 +/- 0.01 mg/dL v 10.0 +/- 0.01 mg/dL (P less than .0001), APO-CIII 10.12 +/- 1.43 mg/dL v 26.0 +/- 2.86 mg/dL (P less than .0005), and APO-E 8.0 +/- 0.02 mg/dL v 12.0 +/- 0.01 mg/dL (P less than .03). These results point out important differences between women and men. In women binephrectomy promotes a decreased concentration of all APO-C but has no influence on APO-AI concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein A-I↗
PubMed1989

Natriuretic factors and lithium clearance in patients with the syndrome of inappropriate antidiuretic hormone (SIADH)

Because the syndrome of inappropriate antidiuretic hormone (SIADH) is a state of disturbed body fluid volume regulation and altered sodium balance we sought to determine if recently described volume regulatory factors were stimulated in SIADH. We measured atrial natriuretic peptide (ANP), endogenous digitalis-like natriuretic factor (EDNF) and urinary free dopamine in SIADH (n = 27). We also determined fractional clearance of lithium (FCLi). The data obtained in SIADH were compared with similar measurements performed in sodium retaining hyponatremias, such as those of heart failure (n = 26), liver cirrhosis (n = 19) and volume contraction (n = 28). We observed: ANP was 19.5 +/- 2.7 fM/ml in SIADH; it was significantly lower than ANP in cardiac failure, but no different from ANP in volume contraction. Urinary free dopamine was 2.2 +/- 0.8 microM/24 h in SIADH; this was significantly higher than in volume contraction and liver cirrhosis. EDNF (259 +/- 42 nM/24 h) and FCLi (21.4 +/- 2%) were both numerically higher in SIADH than in other hyponatremic disorders; however, the differences did not achieve significance. In conclusion, our observations did not establish a specific role of ANP in chronic stable SIADH. As to the importance of EDNF, dopamine and proximal tubular fluid reabsorption (FCLi) additional work using acute volume changes may demonstrate their participation in the renal sodium handling of SIADH more clearly than our study did.

Aged↗