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Biomedical subjects

G Marchetti

Publications and source records attributed to G Marchetti.

At least 19 recordsLinked to original sources
PubMed1979

[Effects of dopamine, noradrenaline and isoproterenol on pulmonary circulation in anesthetized dogs].

Experiments were performed on 19 anaesthetized open-chest dog instrumented with polyethylene catheters inserted: into the aorta, in pulmonary artery and in left atrium and with an electromagnetic flow-transducer placed around the ascending aorta in order to record : systemic arterial and pulmonary pressures, mean left auricular pressure and phasic aortic flow. Heart rate, stroke volume, total systemic and pulmonary resistance, cardiac work were moreover calculated. Each dog was given intravenously by slow infusione : Dopamine (micrograms 5--10--20/kg/min/ 5 min), Isoproterenol (microgram 0.125--0.25--0.5/kg/min/5 min) and Norepinephrine (microgram 0.25--0.5--1 /kg/min/5 min). Results obtained on systemic hemodynamics agree with those reported by many other investigators. On pulmonary circulation : Isoproterenol, at the tested doses, elicited vasodilator effects, Norepinephrine increased total pulmonary resistance but not pulmonary vascular resistance, while Dopamine did not modify or slightly reduced vascular pulmonary tone.

Animals↗
PubMed1979

[Stenosis of hepatic artery associated with portal vein anomaly and splenomegaly: a haemodynamic evaluation (author's transl)].

The authors describe one case of stenosis of the common hepatic artery associated with splenomegaly. After commenting on the rarity and peculiarity of such an occurrence, they explain the decisive role of selective celiac tripod arteriography not only for precise diagnostic definition of the case but also in terms of formulating an appropriate therapeutic program. The study of this case includes a detailed exploration of the hemodynomic situation created by the anomaly in the hepatosplenic district, and an equally detailed study of the associated blood picture changes.

Angiography↗
PubMed1979

[Variations of hematic viscosity due to water-electrolyte disorders induced by muscular stress].

In view of the increasingly widespread tendency of common people to undertake sports activities without adequate athletic preparation, and in consideration of certain cardiovascular alterations detected in subjects cultivating athletic activities of some magnitude for a number of years, the authors set out to explore the effects of severe muscular activity on circulation. More precicely, they measured blood and plasma viscosity at rest and after 50 minutes of intense athletic activity, competitive or otherwise, at the same time looking for possible changes of volemia, blood lipid composition, and hemodynamic parameters. Trained subjects, even if no longer very young, showed viscosity values in the lower range of normal, with no increase following muscular exertion; and likewise no changes of circulating blood volumes. Untrained subjects, conversely, showed more significant increase of both said values, albeit not beyond the limits of norm. The definitely if not dramatically different behavior of the two groups of subjects (trained versus untrained) brings out the value of this simple test. The authors discuss the factors and mechanisms that may be responsible for the observed changes: namely the loss of water and associated changes of electrolyte and protein concentrations, the alterations of blood pH, the changes of paO2, and the increased velocity of blood flow.

Adolescent↗
PubMed1979

[The behavior of blood viscosity in polyglobulism].

In polyglobulic subjects we have found a variable reduction of plasmatic viscosity, with an increase of total viscosity. If the increase of Ht is the first cause of the increase of total viscosity, it is less simple to find the cause of plasmatic viscosity decrease; to this end we have analysed direct and indirect factors (coagulation factors, proteinous and lipidic components). We haven't found any significant qualitative alterations. It is proposed the importance of the interventions of basic proteins of polication type. To this end it has been studied the connection between plasmatic viscosity and ESR, being both influenced by the same factors, but in a contrary way and with variable results. Then the role of plasmatic viscosity in these subjects, in substitution of ESR, is significant.

Adult↗
PubMed1979

[Variations of hematic and plasmatic viscosity as a function of flow velocity, analyzed by means of an experimental model].

The authors have determined the hematic and plasmatic viscosity in 60 sound subjects, 30 men and 30 women respectively, at different values of cut drop, corresponding to the values that can be found at different levels of circulatory system. These subjects had value of Ht, total protidemy, cholesterolemy and trigliceryds, included in normal limits. For these determinations, made at constant temperature, they have used Well-Brookfield with a divergent angle of 0,8 degrees. In this way they could determinate the normality limits of hematic and plasmatic viscosity, in men and women, in connection with the physiologic modifications of flux speed. It has been confirmed the tixotropo behaviour of blood, whose viscosity increases exponentially for lessenings of cut drop and we have put this fact in touch with genesis of thrombosis. They haven't shown any expressive difference in the behaviour of the curves of two undergroups; the curve of middle values is higher for men, and it seems that this difference is owing to Ht. esclusively. In the end they have considered the curves of subjects that had values of viscosity different from normality; in this way they have found three different curves, in pathologic conditions.

Blood Flow Velocity↗
PubMed1978

Hemodynamic and metabolic changes induced by temporary clamping of the thoracic aorta.

Numerous authors reported a significant deterioration of heart function induced by aortic cross-clamping. Nevertheless, the aorta has been clamped during various surgical procedures without any complication. We studied the hemodynamic and metabolic variations induced by 20 min thoracic aorta cross-clamping in 6 open-chest dogs. During clamping the most striking modifications were an increase in coronary blood flow of over 65%, an increase in cardiac work of over 77% and an increase in total peripheral resistances of over 68% compared to base values. No significant variations were found in the heart rate and cardiac index. Metabolic parameters, such as O2 consumption and lactate consumption increased significantly during the clamping period. The increase in lactate consumption and the progressive and continuous improvement in oxygenation indexes (lactate/pyruvate, redox potential, excess of lactate) proved the absence of any myocardial anoxia during this period. Within 15--30 min after declamping all hemodynamic and metabolic parameters reverted to values close to basal values. These data strongly suggest that the mammalian heart can tolerate this procedure satisfactorily for a limited period of time. In clinical settings, one should consider the base conditions of the cardiovascular system before transposing these conclusions.

Animals↗
PubMed1978

Effects of creatinol-O-phosphate (COP) on haemodynamics and cardiac metabolism in conscious and anaesthetized dogs.

The effects of creatinol-O-phosphate (COP, Aplodan) have been studied on haemodynamics and cardiac metabolism of virtually normal heart (conscious dogs with electromagnetic probes chronically implanted) and progressively failing heart (open chest anaesthetized dogs). The results obtained show that COP in both series of experiments increased cardiac work and improved some myocardial metabolic parameters (delta redox potential across the heart, lactate/pyruvate ratio, excess lactate) probably by enhancing the myocardial O2 supply-consumption ratio, and consequently increasing the amount of O2 available for energetic reactions in the cardiac muscle and possibly in other tissues as well.

Animals↗
PubMed1978

Pharmacokinetics of deslanatoside C-3H administered parenterally to the guinea-pig, rabbit and dog.

The pharmacokinetics of Deslanatoside C-3H, a short-acting polar cardiac glycoside, were investigated in the guinea-pig, rabbit and dog, after parenteral administration. Deslanatoside C was on average 20% plasma protein-bound and had a red blood celle/plasma partition ratio of 1/9. Tissue uptake of Deslanatoside C observed in the guinea-pig seems on average to be higher than in rabbits. Among the various organs and fluids tested, the highest levels were encountered in the urine, bile and kidneys of both the guinea-pig and rabbit. The main excretory route of this glycoside was via the urine, although significant amounts were excreted via the bile in all the three species tested. Cumulative urinary excretion 24 hr after i.v. injection was 50% (75% of which in unchanged form) in the guinea-pig, 46.5% (86% of which in unchanged form) in the rabbit, and 42.9%(84% of which in unchanged form) in the dog. Among the cardiac glycosides, Deslantoside C seems to possess the highest urinary excretion rate, which has in fact also recently been confirmed in human subjects.

Animals↗