Medical University of South Carolina

About: Medical University of South Carolina is a education organization based out in Charleston, South Carolina, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 23436 authors who have published 45440 publications receiving 1769397 citations. The organization is also known as: MUSC & Medical College of the State of South Carolina.

Adrenergic effects on the biology of the adult mammalian cardiocyte.

Abstract: BACKGROUNDTo delineate the mechanism(s) of catecholamine-mediated cardiac toxicity, we exposed cultures of adult cardiac muscle cells, or cardiocytes, to a broad range of norepinephrine concentrations.METHODS AND RESULTSNorepinephrine stimulation resulted in a concentration-dependent decrease in cardiocyte viability, as demonstrated by a significant decrease in viable rod-shaped cells and a significant release of creatine kinase from cells in norepinephrine-treated cultures. Norepinephrine-mediated cell toxicity was attenuated significantly by beta-adrenoceptor blockade and mimicked by selective stimulation of the beta-adrenoceptor, whereas the effects mediated by the alpha-adrenoceptor were relatively less apparent. When norepinephrine stimulation was examined in terms of cardiocyte anabolic activity, there was a concentration-dependent decrease in the incorporation of [3H]phenylalanine and [3H]uridine into cytoplasmic protein and nuclear RNA, respectively. The decrease in cytoplasmic labeling was largel...

Disruption of hyaluronan synthase-2 abrogates normal cardiac morphogenesis and hyaluronan-mediated transformation of epithelium to mesenchyme

Abstract: We identified hyaluronan synthase-2 (Has2) as a likely source of hyaluronan (HA) during embryonic development, and we used gene targeting to study its function in vivo. Has2(-/-) embryos lack HA, exhibit severe cardiac and vascular abnormalities, and die during midgestation (E9.5-10). Heart explants from Has2(-/-) embryos lack the characteristic transformation of cardiac endothelial cells into mesenchyme, an essential developmental event that depends on receptor-mediated intracellular signaling. This defect is reproduced by expression of a dominant-negative Ras in wild-type heart explants, and is reversed in Has2(-/-) explants by gene rescue, by administering exogenous HA, or by expressing activated Ras. Conversely, transformation in Has2(-/-) explants mediated by exogenous HA is inhibited by dominant-negative Ras. Collectively, our results demonstrate the importance of HA in mammalian embryogenesis and the pivotal role of Has2 during mammalian development. They also reveal a previously unrecognized pathway for cell migration and invasion that is HA-dependent and involves Ras activation.

Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke

Abstract: BACKGROUND: Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared the efficacy and safety of two antiplatelet regimens--aspirin plus extended-release dipyridamole (ASA-ERDP) versus clopidogrel. METHODS: In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive 25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive 75 mg of clopidogrel daily. The primary outcome was first recurrence of stroke. The secondary outcome was a composite of stroke, myocardial infarction, or death from vascular causes. Sequential statistical testing of noninferiority (margin of 1.075), followed by superiority testing, was planned. RESULTS: A total of 20,332 patients were followed for a mean of 2.5 years. Recurrent stroke occurred in 916 patients (9.0%) receiving ASA-ERDP and in 898 patients (8.8%) receiving clopidogrel (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11). The secondary outcome occurred in 1333 patients (13.1%) in each group (hazard ratio for ASA-ERDP, 0.99; 95% CI, 0.92 to 1.07). There were more major hemorrhagic events among ASA-ERDP recipients (419 [4.1%]) than among clopidogrel recipients (365 [3.6%]) (hazard ratio, 1.15; 95% CI, 1.00 to 1.32), including intracranial hemorrhage (hazard ratio, 1.42; 95% CI, 1.11 to 1.83). The net risk of recurrent stroke or major hemorrhagic event was similar in the two groups (1194 ASA-ERDP recipients [11.7%], vs. 1156 clopidogrel recipients [11.4%]; hazard ratio, 1.03; 95% CI, 0.95 to 1.11). CONCLUSIONS: The trial did not meet the predefined criteria for noninferiority but showed similar rates of recurrent stroke with ASA-ERDP and with clopidogrel. There is no evidence that either of the two treatments was superior to the other in the prevention of recurrent stroke. (ClinicalTrials.gov number, NCT00153062.)

Efficacy and safety of sirolimus in lymphangioleiomyomatosis.

Abstract: Background Lymphangioleiomyomatosis (LAM) is a progressive, cystic lung disease in women; it is associated with inappropriate activation of mammalian target of rapamycin (mTOR) signaling, which regulates cellular growth and lymphangiogenesis. Sirolimus (also called rapamycin) inhibits mTOR and has shown promise in phase 1–2 trials involving patients with LAM. Methods We conducted a two-stage trial of sirolimus involving 89 patients with LAM who had moderate lung impairment — a 12-month randomized, double-blind comparison of sirolimus with placebo, followed by a 12-month observation period. The primary end point was the difference between the groups in the rate of change (slope) in forced expiratory volume in 1 second (FEV1). Results During the treatment period, the FEV1 slope was −12±2 ml per month in the placebo group (43 patients) and 1±2 ml per month in the sirolimus group (46 patients) (P<0.001). The absolute between-group difference in the mean change in FEV1 during the treatment period was 153 ml, o...