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Effects of furosemide on blood pressure in anephric rats.
No full textThis study has been performed in order to evaluate whether furosemide can induce changes in blood pressure independently of its diuretic effects,and whether its pressor effects are connected with the ability to synthetize renal prostaglandins. The experiments were performed in four groups of volume-expanded rats: the first (n.5) had bilateral ligation of the renal vessels; the second (n.8) had bilateral ligation of the ureters; the third group (n.6) had ureters ligation after pre-treatment with indomethacin; the fourth group (n.2) received a pre-treatment with captopril. After blood pressure stabilization, furosemide was administered i.v. (0.125 mg/100 g. of body weight). Indirect readings of the blood pressure were obtained at 1, 2, 3, 4, 5, 7.5, 10, 15, 20 min. After furosemide administration, blood pressure fell down quickly in the rats with ureteral ligation and in those with captopril pretreatment, while the tensive response to furosemide was blunted by the indomethacin treatment. In conclusion, furosemide can reduce blood pressure by a mechanism non related with its diuretic properties, which, however, requires the integrity of the renal connections with the circulatory system
EVALUATION OF INSULIN-INDUCED CHANGES IN THE RENAL RESPONSE TO FUROSEMIDE IN NORMAL SUBJECTS
No full textOver the last years, a large mass of information has accumulated indicating that changes in the serum insulin concentration can affect renal electrolyte excretion. We analyzed the response of the kidney to furosemide in 5 healthy men, in the presence of both normal physiological serum insulin levels and levels at the upper limit of the physiological range, obtained by the hyperinsulinemic-euglycemic clamp technique. After furosemide administration, glomerular filtration rate, urine flow, urine sodium excretion, free water clearance, urine pH, plasma renin activity and plasma aldosterone exhibited the same behavior in the presence of both serum insulin concentrations. The rise in urinary potassium excretion following furosemide administration was significantly lower in the presence of high insulin concentrations. Although we observed a slight decrease in plasma potassium levels during the equilibration phase of the clamp required before the administration of furosemide, a significantly lower increase in potassium fractional excretion indicated a direct tubular effect of insulin. Thus, in conditions in which natriuresis is mildly stimulated, as in the case of the administration of low doses of furosemide, insulin does not affect the rate of renal sodium reabsorption. Conversely, the hormone has an appreciable influence on the modulation of tubular potassium exchanges
Renal response to furosemide in normal subjects during hyperinsulinaemic clamp.
No full textThe study has been performed in an attempt to provide further data on the supposed direct action of insulin on the kidney, based on the assumption that any effect of insulin on sodium reabsorption via co-transport should shift the dose-response curve to the furosemide administration. In five normal male volunteers plasma insulin concentration was changed by means of a hyperinsulinaemic euglycaemic clamp. The diuresis and natriuresis following intravenous injections of furosemide (in increasing doses) were measured in basal conditions and during clamp. No significant difference was found between the experiments performed in the two conditions. Our study has not identified a direct sodium-retaining effect of insulin on the furosemide-sensitive mechanisms of the renal tubule
INSULIN HYPERSECRETION - A DISTINCTIVE FEATURE BETWEEN ESSENTIAL AND SECONDARY HYPERTENSION
No full textSeveral studies have demonstrated that patients with hypertension have greater plasma insulin levels than normotensive subjects. The aim of the present study was to clarify if hyperinsulinemia in hypertension is a consequence of either increased pancreatic secretion or decreased hepatic clearance, and to determine whether abnormalities of glucose metabolism are equally present in essential and secondary hypertension. In an observational cross-sectional study, fasting blood glucose, plasma insulin, and plasma C-peptide levels were measured in five patient groups: 34 lean normotensive, 19 overweight normotensive, 25 lean essential hypertensive, 27 overweight essential hypertensive, and 20 secondary hypertensive subjects. The blood glucose/plasma insulin and plasma insulin/plasma C-peptide ratios were calculated as indexes of insulin sensitivity and hepatic insulin clearance, respectively. Subjects with essential hypertension and, to a greater extent, those who were overweight, exhibited significantly higher fasting insulin and C-peptide levels and significantly lower glucose/insulin ratios as compared with lean normotensive subjects. In contrast, no differences were observed between secondary hypertensive and control subjects. Mean blood pressure was significantly and independently correlated to body mass index, plasma insulin and plasma C-peptide levels, and the glucose/insulin ratio. In lean essential hypertensive and secondary hypertensive subjects, the insulin/C-peptide ratios were comparable to controls, indicating normal hepatic insulin clearance. In both overweight groups, a trend to increased insulin/C-peptide ratios was observed. This study shows that in essential hypertensive subjects, hyperinsulinemia is caused by insulin hypersecretion, whereas in overweight subjects, both increased insulin secretion and decreased hepatic insulin clearance might be involved
IPERSPLENISMO IN CORSO DI MALATTIA DI GAUCHER: CASO CLINICO E REVISIONE DELLA LETTERATURA
No full textACUTE RENAL-FAILURE IN PAROXYSMAL-NOCTURNAL HEMOGLOBINURIA WITH SPLANCHNIC VENOUS THROMBOSES
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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