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Biomedical subjects

R Leor

Publications and source records attributed to R Leor.

15 recordsLinked to original sources

An undocumented effect of lidocaine revealed by computerized electrocardiography.

The influence of an intravenous push of lidocaine 1 mg/kg followed by 2 mg/min infusion on total QRS amplitude and R-to-S duration in leads V2-V4 of the electrocardiogram was studied in 11 patients who were hospitalized in the coronary care unit. A computerized system sampled the amplitude and timing of peak R and S waves of 1100 QRS complexes of leads V2-V4, starting two minutes before the first push of lidocaine. Curves of amplitude and R-to-S duration versus time were obtained in all patients. QRS amplitude in V2 and V3 increased significantly in 10 of 11 patients (p < 0.005). The mean voltage increase for all patients was 0.1 +/- 0.07 millivolt. The authors also observed a mild prolongation of R-to-S duration (0.8 +/- 1.0 millisecond p < 0.02). This new finding, obtained by a simple computerized system, may possibly have potential future practical clinical application as a feedback parameter for closed-loop control systems for the administration of lidocaine.

Adult↗

Unstable anginal syndrome and pulmonary oedema due to thyrotoxicosis.

We report on a 40 year old woman who presented with typical unstable angina pectoris associated with pulmonary oedema, due to poorly controlled hyperthyroidism. No cardiac abnormality was detected by echo-Doppler and nuclear ventriculography. Coronary angiography demonstrated normal coronary arteries. This case represents a new manifestation of the known association of cardiac ischaemia with hyperthyroidism in the presence of normal coronary arteries.

Adult↗

The influence of pH on the intravenous delivery of lidocaine solutions.

In order to evaluate the surface tension lowering effect of lidocaine 0.4% on a 5% glucose solution, drop size has been measured in intravenous sets of 60 drops per ml. The relationship between the number of drops per ml and the pH of the solution was sigmoidal, from 63 drops/ml at pH5 to 95 drops/ml at pH 10. Without lidocaine, the effect of pH on the drop count of the 5% glucose solution was negligible. The surface tension lowering effect of lidocaine may account for significant decreases in apparent bioavailability and delivered lidocaine when high pH solutions are used with drop counting infusion pumps.

Biological Availability↗

Influence of ethanol on the delivery of intravenous nitroglycerin solutions.

In order to evaluate the surface tension lowering effect of ethanol in intravenous nitroglycerin solutions of varying concentrations, drop size was measured in intravenous transfusion sets that should deliver 60 drops/ml. Ethanol 5% solutions led to a significant decrease in drop volume and a concomitant increase in the number of drops per unit volume, up to 79 drops/ml were observed. The surface tension lowering effect may account for decreases of up to 25% in delivered nitroglycerin when drop counting infusion pumps are used, and may be a factor in the development of apparent tolerance to intravenous nitroglycerin.

Ethanol↗

Laetrile intoxication and hepatic necrosis: a possible association.

A 65-year-old woman with cirrhosis and hepatoma lapsed into deep coma, hypotension, and acidosis after ingestion of 3 gm of Laetrile, a cyanogenetic glucoside. After initial treatment, the patient regained consciousness, but massive hepatic damage led to her death. We suggested a possible relationship between Laetrile poisoning and massive hepatic necrosis.

Aged↗

Neurocirculatory asthenia and mitral valve prolapse--two unrelated entities?

Patients with neurocirculatory asthenia share common symptoms with patients having evidence of mitral valve prolapse. A link between these two conditions has been suggested but never documented. We have evaluated the prevalence of mitral valve prolapse among 42 young soldiers suffering from the neurocirculatory asthenia syndrome, using auscultation and echocardiography to detect the mitral abnormality. Four of the 42 subjects with neurocirculatory asthenia had both auscultatory and ultrasonic evidence of mitral valve prolapse. Since a similar prevalence of mitral valve prolapse has been reported among populations of presumably healthy young males or females, we conclude that mitral valve prolapse and neurocirculatory asthenia do not appear to be related.

Adult↗

Prostaglandins and the antiarrhythmic effect of preconditioning in the isolated rat heart.

Our study evaluated the relationship between the endogenous production of prostacyclin and the antiarrhythmic effect of ischemic preconditioning against ischemic and reperfusion-induced tachyarrhythmia. Langendorff perfused rat hearts underwent 30 min regional ischemia with reperfusion. Preconditioning was induced by a single episode of 5 min ischemia and 15 min reperfusion. Prostaglandin 6-keto F1 alpha (a stable metabolite of prostacyclin) was determined in the coronary effluent. In the control group the incidence of tachyarrhythmia was 31% during ischemia and 67% during reperfusion. Preconditioning did not affect ischemic arrhythmias but attenuated arrhythmias a reperfusion (8%, p < 0.01) and was associated with increased release of prostacyclin prior to reperfusion. Aspirin abolished the antiarrhythmic effect of preconditioning against reperfusion tachyarrhythmias. However, no relationship was found between suppression of prostacyclin production and the occurrence of arrhythmia in individual hearts. Thus, our findings suggest that metabolites of arachidonic acid via the cyclooxygenase pathway are involved in the protective effect of ischemic preconditioning against reperfusion-induced tachyarrhythmias.

6-Ketoprostaglandin F1 alpha↗