These data demonstrate that during right coronary artery occlusion and with reperfusion, bradycardia and hypotension develop more commonly in patients with proximal occlusions compared with those with distal occlusions. These findings suggest that reflexes arising from the ischemic right ventricle may play a role in bradyarrhythmias and hypotension.
The study goal was to evaluate the transplacental transfer of two corticosteroids, budesonide (BUD) and fluticasone propionate (FP), in pregnant mice and investigate whether P-glycoprotein (P-gp) might be involved in reducing BUD transplacental transfer. Pregnant mice (N = 18) received intravenously either low (104.9 μg/kg) or high (1049 μg/kg) dose of [ 3 H]-BUD or a high dose of [ 3 H]-FP (1590 μg/kg). In a separate experiment, pregnant mice (N = 12) received subcutaneously either the P-gp inhibitor zosuquidar (20 mg/kg) or vehicle, followed by an intravenous infusion of [ 3 H]-BUD (104.9 μg/kg). Total and free (protein unbound) corticosteroid concentrations were determined in plasma, brain, fetus, placenta, kidney, and liver. The ratios of free BUD concentrations in fetus versus plasma K (fetus, plasma, u, u) 0.42 ± 0.17 (mean ± SD) for low-dose and 0.38 ± 0.18 for high-dose BUD were significantly different from K = 1 (P < 0.05), contrary to 0.87 ± 0.25 for FP, which was moreover significantly higher than that for matching high-dose BUD (P < 0.01). The BUD brain/plasma ratio was also significantly smaller than K = 1, while these ratios for other tissues were close to 1. In the presence of the P-gp inhibitor, K (fetus, plasma, u, u) for BUD (0.59 ± 0.16) was significantly increased over vehicle treatment (0.31 ± 0.10; P < 0.01). This is the first in vivo study demonstrating that transplacental transfer of BUD is significantly lower than FP's transfer and that placental P-gp may be involved in reducing the fetal exposure to BUD. The study provides a mechanistic rationale for BUD's use in pregnancy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.