Effect of intravenous metoprolol or intravenous metoprolol plus glucagon on dobutamine-induced myocardial ischemia.

STUDY OBJECTIVE: To determine the effect of metoprolol on dobutamine stress testing with technetium-99m sestamibi single-photon emission computed tomography imaging and ST-segment monitoring, and to assess the impact of intravenous glucagon on metoprolol's effects. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Community hospital. PATIENTS: Twenty-two patients with known reversible perfusion defects. INTERVENTION: Patients underwent dobutamine stress tests per standard protocol. Before dobutamine was begun, no therapy was given during the first visit, and patients were randomized on subsequent visits to receive metoprolol or metoprolol plus glucagon 1 mg. Metoprolol was dosed to achieve a resting predobutamine heart rate below 65 beats/minute or a total intravenous dose of 20 mg. MEASUREMENTS AND MAIN RESULTS: Metoprolol reduced maximum heart rate 31%, summed stress scores 29%, and summed difference scores 43% versus control. Metoprolol plus glucagon also reduced the maximum heart rate 29% versus control. Summed stress and summed difference scores were not significantly reduced, although they were 18% and 30% lower, respectively, than control. No significant differences were found in any parameter between metoprolol and metoprolol-glucagon. CONCLUSION: During dobutamine stress testing, metoprolol attenuates or eliminates evidence of myocardial ischemia. Glucagon 1 mg, although somewhat effective, does not correct this effect to the extent that it can be administered clinically.

Antispermatogenic and androgenic activities of various extracts of Hibiscus rosa sinesis in albino mice.

The benzene chloroform and alcoholic extracts of the flowers of H.r.sinensis were administered (i.p.) at two different dose levels of 125 and 250 mg/kg body weight to adult male albino mice for 20 days. The results have shown decrease in the spermatogenic elements of testis and epididymal sperm count. High content of testicular cholesterol may be due to lowered androgen synthesis. The increase in the weight of accessory reproductive organs indicates the androgenicity of the plant extract itself, which is proved in the present study by testing the benzene extract in immature mice.

Effect of benzene extract of Hibiscus rosa sinensis on the estrous cycle and ovarian activity in albino mice.

The benzene extract of Hibiscus rosa sinensis flowers was administered intraperitoneally at the dose levels of 125 and 250 mg/kg body weight to adult mice and resulted in an irregular estrous cycle with prolonged estrus and metestrus. An increase in the atretic follicles and the absence of corpora lutea indicate the antiovulatory effect of the extract. The extract also showed estrogenic activity in immature mice by early opening of the vagina, premature cornification of the vaginal epithelium and an increase in uterine weight. Therefore the antiovulatory effect may be due to an imbalance in the hormonal environment, as there may be an increase in the endogenous secretion of estrogen by atretic follicles, and also to the estrogenicity of the flower extract.