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Biomedical subjects

M Pellet

Publications and source records attributed to M Pellet.

At least 19 recordsLinked to original sources
PubMed1980

Effect of acidosis, alkalosis and monofluoroacetate administration on citrate and ATP content of rat renal medulla and papilla.

1. --Renal distribution of citrate showed that there is an increase in citrate content from cortex to medulla and a decrease from medulla to papilla. Alkalosis produced an increase in citrate content and acidosis a decrease in renal citrate content, in each of the studied renal area. Monofluoroacetate produced no significant change in citrate content of medulla or papilla; it did not interfere with the acido-basic related changes in cortex citrate content, but its effect was additive. 2. --Renal distribution of ATP significantly decreased from cortex to medulla and from medulla to papilla. Acid or basic diet had no influence on intratissular ATP content. Fluoroacetate decreased renal ATP content.

Acidosis↗
PubMed1979

In vitro citrate synthesis by the dog kidney. Investigations with cortex, red and white medulla slices.

In vitro utilization or production of citrate by the cortex, outer medulla or inner medulla of dog kidney was measured. Our data show: 1. An in vitro citrate synthesis or utilization capacity of the cortex greater than that of the red medulla. 2. An effect of pH on citrate synthesis or utilization capacity of the cortex, an effect not seen with medullary slices. 3. An absence of citrate synthesis or utilization by white medulla slices. It would seem that the citrate found in the white medulla and the papilla of the dog kidney in vivo was not produced in situ.

Animals↗
PubMed1978

Lactate and pyruvate metabolism in isolated renal tubules of normal dogs.

The kinetics of lactate and pyruvate (1 and 5 mM in each case) metabolism was studied in isolated dog renal tubules. Utilization of these two substrates and the production of glucose, pyruvate, or lactate, and alanine were determined. The rates of lactate and pyruvate utilization and of glucose production were constant during 60 min of incubation. Glucose production from pyruvate was less than that from lactate. Addition of albumin to the incubation medium greatly inhibited lactate and pyruvate utilization at both substrate concentrations. It stimulated, however, glucose production from 1 mM, but not 5 mM, lactate or pyruvate. These effects were found to be due to the presence of fatty acids in the albumin solution used. In the absence of fatty acids, glucose production represented 35 to 40% of lactate uptake, but represented less than 20% of pyruvate uptake. Fatty acids markedly enhanced the percentage of transformation of lactate and pyruvate into glucose, and that of pyruvate into lactate. Alanine represented 20% or less of lactate and pyruvate uptake. These results suggest that fatty acids have a regulatory influence on lactate and pyruvate dog kidney metabolism.

Alanine↗
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↗
PubMed1975

[Changes in renal function in the hours following an intravenous injection of acebutolol].

A study was carried out, of the changes of renal functional value and of urinary electrolytes excretion after rapid intravenous injection of acebutolol in twelve subjects with various glomerular filtration. Renal functional value was estimated by measuring inuline. P.A.H., urea and creatinin clearances during a control period of thirty minutes and during the four hours following administration of acebutolol. The variations in the excretion of electrolytes: chloride, sodium, potassium, calcium and phosphorus were measured during the same periods. The following results were obtained: in subjects with normal renal functional value, administration of acetubolol brings about: a variation which is under 20 p.cent of glomerular filtration and P.A.H. clearance; a 50 p.cent average decrease of natriuresis. in cases of renal insufficiency: clearances of inuline and P.A.H. are unchanged. There is a 20 p.cent average decrease of natriuresis. There is a decrease of urinary output (35-45 p.cent) and of urea clearance (20-50 p.cent).

Acebutolol↗
PubMed1975

Intrarenal distribution of citrate in the dog during antidiuresis and diuresis.

The intrarenal distribution of citrate was evaluated in the dog during antidiuresis and osmotic diuresis, by using the specific citrate assay method of Moellering and Gruber. The measurements were made on tissue samples taken from four different regions throughout the kidney: cortex, outer and inner medulla, and papilla. During antidiuresis, a characteristic distribution of citrate was observed with highest levels in the papilla and lowest ones in the outer medulla. A medullary concentration gradient for citrate was found. Mannitol greatly decreased papillary citrate and sodium, but no changes in outer and inner medullary citrate occured. The results could not be explained by the citrate contained either in the trapped urine or blood in the tissue. It is suggested that citrate accumulation in the inner regions of renal medulla may be accounted for by countercurrent mechanisms or regional differences in renal citrate metabolism.

Animals↗
PubMed1975

Investigation of electrical impedance variations of dog brain tissue during experimental metabolic disturbances.

Experiments were carried out on dogs using bielectrode probes having as adequate impedancemeter. The probe is introduced via a cranial opening into the grey matter. This gives the following: a low frequency reading which is related to the extra cellular fluid component; a high frequency reading which is related to the total overall liquids; and a proportionality ratio of these liquids in the explored volume. The impedance variations are functions of the nature and intessity of vascular disturbance. Variation of the low frequency impedance (5 kHz) is the most significant. The experimental prodedure consists of: 1) Abrupt and permanent circulatory arrest; 2) Circulatory reduction by haemorrhage followed by recovery (if necessary by means of blood transfusion); 3) Anoxia by CO inhalation, recovery affected by means of O2 inhalation; and 4) Hypoglycemic coma induced by intravenous injection of insulin. The changes in the biochemical state of the cerebral tissue give very large variations of the low frequency impedance. It is these variations which are to constitute the object of this communication.

Animals↗
PubMed1975

[Intrarenal distribution of calcium and magnesium in the dog. Effect of an osmotic diuresis (author's transl)].

1 The determination of Na, Ca, Mg, and K concentrations was performed in four different regions of the dog kidney (cortex, outer medulla, inner medulla, and papilla) during antidiuresis and during an osmotic diuresis. 2 The results show a medullary concentration gradient for calcium. This gradient is much higher than that found for sodium. 3 An inverse concentration gradient from cortex to inner medulla for Mg and K is found. 4 An osmotic diuresis (hypertonic mannitol) decreases the corticomedullary gradient of Na, but does not alter significantly the intrarenal distribution of Ca, Mg and K. 5 These results consistent with an intracellular localization of Mg and K in the renal tissue. It is suggested that the medullary concentration gradient for Ca may be due either to a countercurrent multiplier system similar to that for Na, or to a higher tissular fixation of Ca in the inner medulla and papilla than in the outer medulla and cortex.

Animals↗
PubMed1975

[Calcium and magnesium concentrations of the renal cortex in the rat. Comparison of 3 methods of tissular extraction of the principal cations].

We describe three methods for extraction of main tissular cations : a) dry ashing method; b) wet ashing method with HNO3; c) wet method on fresh tissue with HCIO4. This study allows the determination of tissular concentrations of calcium, magnesium in renal cortex of the Rat. Our findings show : a loss of Na, K cations probably by volatilization with dry ashing method ; inability for K determination when HCIO4 method is used ; tissular concentrations are : 4,7 mEq Ca ; 21,6 mEq Mg per kg of wet tissue (wet ashing method with HNO3) ; recovery percentage for magnesium is above 100 % (as previously shown by other authors) ; the dry ashing method is less suitable for extraction than the two other methods ; both wet methods lead to similar results and to a recovery percentage near 100 %.

Animals↗
PubMed1975

[Studies of the variations in functional renal values induced by intravenous dopamine].

We studied, on six patients, the variations in functional renal value and urinary excretion of electrolytes during the intravenous administration of dopamine and in the hours immediately following. Two groups of patients are distinguished. In groupe I, all of whom had normal functional renal values, there was no modification of these, while we observed increases in output, in excretion of electrolytes and in the clearance of the uric acid. In group II, composed of patients with renal insufficiencies, the modifications are less definite but the diuretic and saluretic effect is present. The salidiuretic effects of the dopamine would seem to be dissociated from the cardiovascular effects.

Adult↗