Pyrogallol Induces Apoptosis in Human Platelets

Pyrogallol is a polyphenol that generates the superoxide anion. In this study, we investigated the influence of pyrogallol on human platelets. Our data showed that exposure of platelets to pyrogallol induced numerous manifestations of apoptosis including depolarization of mitochondrial inner membrane and release of cytochrome c from the mitochondria. Pyrogallol also induced downstream extra-mitochondrial apoptotic responses, including activation of caspase-3 and phosphatidylserine exposure on the outer leaflet of the plasma membrane. Addition of glutathione significantly rescued cells from pyrogallol- induced apoptosis, as evidenced by a decrease of all markers of apoptosis. Thus, pyrogallol appears to produce depletion of intracellular glutathione content in platelets, the main non-protein antioxidant in the cells. Furthermore, inhibition of γ-glutamyl transpeptidase, an enzyme that plays the main role in the cellular supply of glutathione, reverted the glutathione (GSH) protection over platelet apoptosis. Our results indicate that pyrogallol induces apoptosis by suppressing the natural anti-oxidation in human platelets.

[The prevalence of the principal cardiovascular risk factors in the population of the Azores]

STUDY OBJECTIVE

to characterize the high mortality rate by ischemic heart disease in Azores, by evaluating the main coronary heart disease risk factors prevalence in the population.

DESIGN

sample study referring the population of 5 islands: 37 counties. Aleatory choose in the electoral lists.

SETTING

the selected individuals were convocated by mail to show up at the Hospital for evaluation.

PATIENTS

1089 individuals selected by aleatory choose from the electoral lists.

INTERVENTIONS

the sample was stratified regarding rural (R) and urban (U), by sex feminine (F) and masculine (M), age 20-40 and 40 to 60 years old. All of them were determined three values of blood pressure, and was taken for exact value the medium of the three, inquired the smoking habits and serum lipids were determined. We considered risk factors (RF); blood pressure > 140/90 mmHg, total cholesterol > 200 mg/dl, HDL cholesterol < 35 mg/dl, triglycerides > 180 mg/dl and smoking habits were stratified in three scores: 1: 1-10, 2: 11-20, and 3: more than 20 cigarettes a day.

MAIN RESULTS

total prevalences; HBP 20.4%, smoking habits 33%, total hypercholesterolemia 47.3%, low HDL cholesterol 17.4% and triglycerides 30.5%.

CONCLUSIONS

the values found for total cholesterol, triglycerides and smoking habits were high and superior to the national medium and to those found in reference studies. Preventive strategies are pointed out.

[The circadian profile of ventricular extrasystole]

STUDY OBJECTIVE

to determine the existence of circadian variability (CV) of single ventricular premature beats (VPBs) and study its relationship with the heart rate variation; to compare sub-groups of patients (Pts) with and without antiarrhythmic therapy and with ischemic cardiopathy versus a free structural cardiopathy group.

DESIGN

retrospective study.

PATIENTS AND METHODS

the CV of VPBs was analyzed by Holter monitoring in 147 Pts, 93 male and 54 female with a mean age of 59 +/- 14.6. Seventy seven Pts were not taking antiarrhythmic drugs while 70 were doing it: Amiodarone 23, Propafenone 30, B-Blockers 9, Quinidine and Disopyramide 7, Flecainide 1. Sixty five Pts had ischemic cardiopathy and 37 were free of any structural abnormality. The selection criteria consisted in: 1--more than 100 VPBs/24h; 2--distribution over more than 12 hours; 3--absence of any hour with more than 35% of the total VPBs in the recording. Data were presented in a percentage form and the results evaluation was made by using single and two-harmonic regression models.

MAIN RESULTS

a CV was found to the single VPBs, with minimum values during the nocturnal period and maximum values in the morning, with a significant adjustment to the two-harmonic regression model, defined by the equation y = 4.2 - Q,559 sen (2 pi T/24) - 0.604 cos (2 pi T/24) - 0.417 sen (4 pi T/24) + 0,272 cos (4 pi T/24) (p < 0.001). A strong positive correlation was observed between VPBs and heart rate variability (r = 0.95; p < 0.001). The sub-groups of Pts, whether taking antiarrhythmic drugs or not, also showed a CV with a statistically significant two-harmonic regression pattern, with a major morning increase of VPBs in the antiarrhythmic group. The free structural cardiopathy sub-group displayed a best adjustment to the single harmonic regression model while the ischemic group exhibited a two-harmonic regression pattern.

CONCLUSIONS

a significant circadian variability of VPBs with a bi-modality expression was determined. The majority of the analyzed sub-groups showed the same kind of variation. A strong positive correlation with the heart rate variability was observed.

Comparison of the effects of a controlled-release formulation of isosorbide-5-mononitrate and conventional isosorbide dinitrate on exercise performance in men with stable angina pectoris

Thirty-three men with stable exercise-induced angina pectoris entered a randomized, double-blind, crossover study in which controlled-release isosorbide-5-mononitrate 60 mg once daily was compared with conventional isosorbide dinitrate 20 mg 3 times daily. Each drug was given for 2 weeks. Twenty-eight patients completed the study and data on exercise variables are available in 23 patients. Treatment with either drug resulted in significant antianginal effects, when measured 6 hours after a single dose and after 2 weeks of therapy compared with baseline placebo; however, there were significantly fewer signs of myocardial ischemia during treatment with isosorbide-5-mononitrate. There was no evidence of tolerance to either drug treatment but a significant attenuation of resting blood pressure (but not of exercise blood pressure) was observed with both drugs. Headache was the only clinically significant adverse event during therapy and it occurred more frequently in the isosorbide dinitrate treatment group (p less than 0.05 vs placebo); 3 such patients had to withdraw from the study because of headache. Thus, once-daily, controlled-release isosorbide-5-mononitrate appears as effective as conventional isosorbide dinitrate 3 times daily in patients with stable angina pectoris. The once-daily administration is convenient and improves patient compliance.