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Biomedical subjects

F Rengo

Publications and source records attributed to F Rengo.

At least 217 records · Page 12Linked to original sources
PubMed1978

[Specificity of systolic anterior motion of the mitral valve in the echocardiographic diagnosis of hypertrophic cardiomyopathy (author's transl)].

In order to determine the prevalence of sistolic anterior motion (SAM) of the mitral valve, we evaluated the echocardiographic records of 229 consecutive patients with a variety of cardiovascular conditions. SAM was present in all the 9 patients of this series with hypetrophic cardiomyopathy and in additional 4 patients with other conditions. Their diagnosis were: arterio-venous fistula of the forearm, tetralogy of Fallot, Prinzmetal angina and idiopatic hypercynetic cardio-circulatory state. Thus SAM without hypertrophic cardiomyopathy is not a rare event in patients undergoing echocardiography. The wide variability of conditions associated with SAM suggests that it represents a functional and aspecific abnormality and does not involve peculiar anatomic factors.

Cardiomyopathies↗
PubMed1978

[Usefulness of x-ray parameters in the functional evaluation of patients with nonvalvular cardiopathies].

In 49 patients suffering of heart diseases we have studied the changes of radiologic cardiac measurements and systolic time intervals (STI) in the four functional classes of the New York Heart Association (NYHA) classification, investigating also the existence of any relationship between these different parameters. Only the patients in functional classes 3rd and 4th showed significant changes in STI and radiologic measurements as compared to the control group. Moreover, a significant negative correlation has been observed between relative heart volume and left ventricular ejection time (LVET) (r = 0.69, P less than 0.001) and LVETc (r = 0.82, P less than 0.001) and a positive correlation between relative heart volume and pre-ejection period (PEP) (r = 0.59, P less than 0.01) and PEP/LVET ratio (r = 0.75, P less than 0.001). These results seem to demonstrate that relative heart volumetry is a fairly accurate index of the cardiac conditions in non valvular heart diseases.

Adult↗
PubMed1977

Effects of guanethidine on histamine release during reflex vasodilatation in the dog.

1 The effects of guanethidine pretreatment on the release of [14C]-histamine during the reflex vasodilatation induced in the atropinized gracilis muscle by rapid intravenous administration of noradrenaline, were studied in dogs. 2 After guanethidine treatment the haemodynamic reflex response was completely abolished and no appreciable modification of [14C]-histamine release from the gracilis muscle following intravenous noradrenaline was observed. 3 These results suggest the hypothesis that the withdrawal of the sympathetic discharge represents the mechanism of histamine release during the reflex vasodilatation. Therefore, guanethidine would suppress both the passive and the histaminergic component of the baroreceptor reflex through the abolition of the sympathetic tone.

Animals↗
PubMed1977

Reduction of blood flow following ischemia in arteriopathic patients: reversion of the phenomenon induced by propranolol.

In most arteriopathic patients, the release of a transitory ischemia in the affected limb reduces blood flow, instead of increasing it as in normal subjects. In this study the effects of propranolol administration on this paradoxical response have been investigated. After rheographic tracings were recorded in 14 arteriopathic patients in the basal condition and in the postischemic period, 10 mg of propranolol was administered IV and the protocol was then repeated. The blood flow in the affected area, measured as Jantsch's index of the rheographic tracings, was 0.63 +/- 0.04 in the basal condition and was reduced to 0.51 +/- 0.05 (P less than 0.001) in the postischemic period. When the ischemia was repeated after propranolol administration, Jantsch's index rose from 0.57 +/- 0.04 to 0.85 +/- 0.09 (P less than 0.01). The reversion of the paradoxical response to the ischemia induced by propranolol administration suggests that the beta-adrenergic blockade can increase blood flow to the ischemic area, probably through a constrictive action on arterovenous connections.

Arteriosclerosis↗
PubMed1977

Studies on the mechanism underlying the influence of alanine infusion on glucose dynamics in the dog.

These experiments have been designed to study the influence of alanine infusion of glucose dynamics in the dog and to further elucidate the role of pancreatic hormones in the interaction of alanine with glucose homeostasis. The primed constant infusion of glucose-2-t was used in order to quantitate the rates of glucose production by the liver (Ra) and glucose utilization (Rd). In a first group of experiments, the intravenous infusion of alanine at the rate of 2 mg./kg./min. produced a moderate enhancement of plasma insulin (IRI), while pancreatic glucagon (IRG) increased more consistently. This different pattern of IRI and IRG response caused the insulin/glucagon molar ratio to decline progressibely throughout the experiment. Both rates of glucose turnover increased significantly during alanine infusion. Since Ra rose more rapidly thanRd did initially, hyperglycemia developed. Later, glucose production slowly decreased and, in spite of the sustained hyperglucagonemia, reached levels very close to the baseline in the second part of the experiment. A significant direct correlation between Ra and IRG was found, while the changes in Ra correlated inversely with those in I/G molar ratio. In a second group of experiments, alanine was infused at the same dose together with 0.4 microng./kg./min. of cyclic somatostatin. In the first part of the infusion, IRG fell more than IRI did, so that I/G ratio increased. Later, IRI levels maintained at low values while IRG returned slowly to the baseline and consequently I/G ratio significantly decreased. Glucose production fell rapidly soon after the beginning of the infusion, and therefore hypoglycemia developed. Later, Ra increased progressively to levels above baseline and plasma glucose returned to the preinfusion levels. As in the the first group of experiments, a significant direct correlation between Ra and IRG and an inverse correlation between the changes in Ra and I/G ratio were observed. These experiments demonstrate that alanine infusion produces an acceleration of glucose turnover and that a clear interrelationship between the release of glucose by the liver and the mobilization of pancreatic hormones exists. Finally, the experiments with somatostatin indicate that hyperglucagonemia is one of the mechanisms underlying the stimulatory effect of alanine on glucose production.

5-Hydroxytryptophan↗
PubMed1977

Histamine mediation in muscular vasodilatation induced by beta adrenoceptor stimulation in dogs.

This study was designed to investigate the possibility of a histamine mediation in muscular vasodilation induced by beta adrenoceptor stimulation. Accordingly, in seven dogs the effects of isoproterenol administration on the release of 14C-histamine from the perfused gracilis muscle were studied. Beta adrenoceptors stimulation induced a vasodilatation, as shown by a decrease in perfusion pressure(-43 +/- 12 mm Hg); simultaneously, a significant increase of the radioactivity measured in the venous blood effluent from the gracilis muscle was observed. Both these events were blocked by propranolol. In the other five dogs, chlorpheniramine was able to reduce the vasodilatation induced by the injection in the gracilis muscle of isoproterenol. Under control conditions, isoproterenol induced a fall in perfusion pressure of 44 +/- 5 mm Hg while, after chlorpheniramine, perfusion pressure decreased by only 24 +/- 4 mm Hg. The results of this study seem to confirm the possibility of a histamine mediation in isoproterenol-induced vasodilatation. However, further investigation is needed in order to identify the exact role of histamine in the geneis of this phenomenon.

Animals↗