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Biomedical subjects

G Merchie

Publications and source records attributed to G Merchie.

At least 19 recordsLinked to original sources
PubMed1983

[123I]Insulin metabolism in normal rats and humans: external detection by a scintillation camera.

[123I]Insulin was injected intravenously into rats and the distribution and kinetics of radioactivity were analyzed by external detection with a scintillation camera connected to a computer. When injected alone, [123I]insulin was rapidly taken up by the liver and to a smaller extent by the kidneys. After reaching a maximum at 3 to 5 minutes after injection, liver radioactivity rapidly declined and free iodide appeared in the plasma. After previous saturation of the insulin receptor compartment, [123I]insulin was concentrated by the kidneys only and the rate of appearance of free iodide was markedly decreased. The results demonstrate the potential usefulness of this noninvasive technique to visualize insulin interaction with the liver and kidneys and to study the rate of insulin degradation by each organ in vivo. Preliminary experiments in man demonstrate its feasibility and low radiotoxicity.

Animals↗
PubMed1978

Humoral control by the kidney of intestinal transport to sodium.

The impairment of water and sodium absorption by the jejunum following an acute saline load depends on the dietary balance of sodium, the mucosa-to-serosa unidirectional flux of this ion being modulated by a direct effect of the changes in blood concentration and by a humoral material of renal origin which itself is released as a consequence of either chronic or acute sodium loading. A possible interference of mineralocorticosteroids, angiotensin or antidiuretic hormone seems to be excluded. A positive correlation exists between mucosa-to-serosa sodium flux and glucose absorption. The kidney controls the exchanges of sodium and water in the jejunum as well as in the kidney itself by the way of an endocrine function.

Animals↗
PubMed1976

Renal control of intestinal sodium and water transport in the dog.

The influence of an intravenous infusion of saline on the absorption of water and sodium by the jejunum has been investigated in dogs previously submitted to sodium-rich or poor diets. While the net intestinal transport was reduced in sodium-loaded animals, no response was observed in the sodium-deprived dogs, despite identical changes in arterial pressure, intravascular volume and blood dilution indexes. The intestinal response of sodium-deprived dogs became positive after transplanting to their neck vessels the kidneys removed from sodium-loaded animals, thus demonstrating that the presence in the blood of a humoral message of renal origin is required to permit the inhibition of net transport. The difference of the responses depended on the variations of the mucosa-to-serosa unidirectional flux. The net potassium transport did not change significantly. The experimental conditions made unlikely an interference of mineralocorticosteroids, angiotensin or antidiuretic hormone. The present results suggest that the kidney might modulate sodium transport in the jejunum, and perhaps elsewhere in the body, by the way of an additional endocrine function.

Animals↗
PubMed1976

Description of a computer program for the determination of regional cerebral blood flow.

The regional cerebral blood flow in man was measured, following a short injection 133 Xenon into the internal carotid, by processing the hemispheric clearance curves detected with an Anger gamma-camera. An automatic calculation program is described which permits the estimation of the two compartmental blood flows. The merits of this procedure are discussed.

Cerebrovascular Circulation↗
PubMed1975

131Cs myocardial scintigraphy. Application to assessment of anterior myocardial infarction.

Earlier studies have indicated that caesium-131 is a good myocardial scanning agent for the demonstration of anterior infarcts. One hundred and ten patients with documented anterior myocardial infarction were studied by 131Cs myocardial scintigraphy. An anterior area of decreased uptake of caesium was noted in all but 3 subjects whose necrotic zone was likely to be of small dimensions. In 20 cases, the scintigram showed a definite, sometimes very large, cold area whereas the electrocardiogram failed to display any diagnostic feature of myocardial necrosis. In most of the latter instances, the electrocardiographic diagnosis was obscured by the presence of intraventricular conduction disturbances. In order to visualize the intracardiac cavities, the 131Cs investigation was usually completed by a 113mIn scintigram, which allowed recognition of a parietal aneurysm in 12 of the 18 patients with extensive anterior lesions. In each case, an index of necrosis was computed from planimetric measurements of the infarcted area as compared to the total left ventricular surfact in both the anteroposterior and left anterior oblique projections. This index was shown to correlate with the incidence of major complications developing after the acute episode of coronary occlusion. The sensitivity, specificity, and accuracy of the method are briefly discussed. It is felt that myocardial scintigraphy represents a sound approach to the semiquantitative assessment of anterior myocardial infarction; the clinical usefulness of the technique seems sufficiently demonstrated to prompt further research in this field.

Adult↗