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Biomedical subjects

G Binetti

Publications and source records attributed to G Binetti.

At least 109 records · Page 6Linked to original sources
PubMed1978

[Hemodynamic effects of disopyramide and procainamide in open-chest animals].

Hemodynamic effects of two antiarrhythmic agents, disopyramide and procainamide, have been evaluated in anesthetized open-chest healthy pigs after random administration. At therapeutic plasma concentrations none of these agents proved to have deleterious hemodynamic effects. The most important action was observed after disopyramide infusion and consisted in significant bradycardia which confirmed the known effect on sinus node automaticity of the drug. Left ventricular dp/dt, an index of cardiac contractility, was unchanged after infusion of both drugs. On the ECG intervals, only procainamide provoked a significant prolongation of QTc. It is concluded that at therapeutic dosage disopyramide does not present deleterious hemodynamic effects in animals and proves to be a valid alternative to other traditional antiarrhythmic agents.

Animals↗
PubMed1977

[Study of the precision and limitations in measuring left ventricular pressure and its first time-derivative (author's transl)].

The precision in measuring left ventricular pressure and its first time-derivative has been evaluated with the study of the physical caracteristics of a system currently used for pressure wave sampling. Besides the different catheters, the set-up tested consists of a nylon connector (110 cm) and of two three way stopcocks. Amplitude and phase response, from 1 to 60 Hz, have been obtained testing the system with sinusoidal pressure waves generated by an hydraulic oscillator. Despite mild differences dependent on the different catheters, the system amplifiers remarkably at frequencies above 5 Hz. Above this limit the harmonic content of the left ventricular pressure wave is negligible and can be ignored in defining the basic morphology and the absolute values of the curve. Similary, the amplification of these high frequency harmonics operated by the system does not affect appreciably pressure measurements. In the case of the pressure time-derivative the significant harmonic content is shifted toward higher frequencies. For this reason a reliable dp/dt cannot be obtained with this hydraulic set-up. A maximal hypothetic error, utilizing a Cook 5.2 F 105 cm catheter, of 8-9% and 28-31% has been estimated for pressure and time-derivative measurments respectively.

Cardiac Catheterization↗
PubMed1976

Normal myocardial contractile state in the presence of quinidine.

Since quinidine is one of the few agents available to treat and prevent ventricular arrhythmias in ambulatory patients, its hemodynamic effects have been reevaluated. When given in therapeutic doses to anesthetized mongrel dogs, quinidine significantly reduced heart rate, aortic pressure and flow, but it did not significantly change the first derivative of the left ventricular pressure curve (left ventricular dp/dt) in nine dogs. A subsequent group of dogs was studied after vagotomy and practolol administration to block cardiac reflexes. This group showed significant reductions in heart rate, aortic pressure and left ventricular dp/dt, with the latter returning to predrug control values when preload, afterload and heart rate were maintained constant. These studies suggest that quinidine does not directly affect myocardial contractility when given in therapeutic doses. Furthermore, the reduction in heart rate in these animals provides support for a direct depressant effect of quinidine on the sinus node. The adverse effects of quinidine on cardiac function previously reported may be due to the use of toxic doses or are secondary to quinidine peripheral circulatory effects, rather than due to a direct reduction in cardiac contractile state.

Animals↗
PubMed1976

Problems in assessing infarction size by epicardial mapping: preliminary studies with quinidine.

Some of the laboratory difficulties in assessing infarction size produced by intermittent coronary artery occlusion were demonstrated by using an epicardial mapping technique in anesthetized open-chest dogs. Intermittent occlusion of a left anterior descending coronary artery branch resulted in a marked elevation of the ST segment above the baseline in the areas of the myocardium supplied by this vessel. Repeated occlusions after administration of normal saline as a control produced less ST-segment elevation thn that noted during control occlusions; however, repeated occlusions after infusion of quinidine produced a further lessening in ST-segment elevation. The problems encountered in interpreting these results are emphasized. Long-term coronary occlusion studies were performed in order to correlate epicardial electrograms with histological findings of ischemia or myocardial necrosis. Our investigations show that epicardial mapping tended to underestimate the area of injury, and this limits the interpretation of drug intervention studies such as those in which quinidine is administered. Therefore, caution should be exerted when using epicardial mapping techniques to assess the effect of various pharmacological interventions on infarction size in open-chest dogs.

Animals↗
PubMedDate not supplied

Calcium responses in human fibroblasts: a diagnostic molecular profile for Alzheimer's disease.

We have previously identified alterations of K+ channel function, IP3-mediated calcium release, and Cp20 (a memory-associated GTP binding protein) in fibroblasts from AD patients vs. controls. In the present study we introduce a scoring system based on these response alterations that integrates two or more alterations (and their degree) in AD vs. control fibroblasts. This scoring system generates an index that distinguishes AD patients from controls with both high specificity and sensitivity. We also show that low doses of bradykinin elicit intracellular calcium release almost exclusively in AD cell lines in an all or none fashion that provide a clear measurement of enhanced IP3-mediated function in AD vs. controls.

Aged↗