RESUMEN
Crude methanolic extracts of 37 marine organisms (16 species of flora, 21 species of fauna) were screened for antibacterial properties against 5 strains of bacteria isolated from marine environments. Of these, 10 plant and 9 animal extracts exhibited antibacterial activity against at least one bacterial strain. The extracts of 6 species were active against all the strains: i.e., Stoechospermum marginatum (brown algae), Cymodocea rotundata (seagrass), Petrosia sp. and Psammaplysilla purpurea (sponges), Sinularia compressa (soft coral), and Cassiopeia sp. (jellyfish). Among the plants, Padina tetrastromatica (brown algae) extract exhibited significant activity (9-11-mm inhibition zone at 500 microg per 6-mm disc) against Bacillus pumilus and Pseudomonas vesicularis, while the extracts of Petrosia, Psammaplysilla, and Cassiopeia were strongly active (11-13-mm inhibition zone at 500 microg per 6-mm disc) against B. circulans and P. putida. It was further confirmed that the attachment of bacterial strains on glass slides was inhibited remarkably with increasing concentrations of bioextracts of Petrosia sp. and Psammaplysilla purpurea. The present findings could form the basis for exploring the antibacterial potential of bioactive molecules from some of the marine organisms that exhibited moderate to strong antibacterial properties.
RESUMEN
Two studies of systolic time intervals (STIs) in patients with mild to moderate hypertension (HBP) revealed that no mean change in systolic intervals occurred with pindolol therapy, although some patients had significant alterations in their STIs. Pindolol responders with normal pretreatment preejection period to left ventricular ejection time (PEP/LVET) ratios had a significant increase in this ratio following pindolol therapy, whereas those with abnormal pretreatment PEP/LVET ratios had improvement in this ratio on administration of the drug. Patients on propranolol showed no change in PEP/LVET ratio. Propranolol administration slowed heart rate and lengthened Q-S2, S1-S2, and LVET, however, without altering the Q-S2 and LVET index, indicating that the changes were caused by the effect of propranolol on the heart rate alone. Chlorthalidone in high doses significantly reduced the Q-S2 index and the S1-S2 index, indicating that these changes were not caused by alteration of the heart rate. The second study suggests that STIs may provide a predictive clue for clinical response to pindolol. Patients with normal cardiac function (group I) are more likely to respond to pindolol than are those with abnormal cardiac function (group II). Directionally opposite changes in STIs in the two subgroups suggest different mechanisms for changing cardiac function. Pindolol's dual role as a beta-blocking agent with intrinsic sympathomimetic activity is proposed as a possible explanation, beta-blocking effects predominating in group I and sympathomimetic activity balancing the beta effect in group II.