Jahangir, Arshad

Background— The primary aim and central hypothesis of the study are that a designated syncope unit in the emergency department improves diagnostic yield and reduces hospital admission for patients with syncope who are at intermediate risk for an adverse cardiovascular outcome. Methods and Results— In this prospective, randomized, single-center study, patients were randomly allocated to 2 treatment arms: syncope unit evaluation and standard care. The 2 groups were compared with χ 2 test for independence of categorical variables. Wilcoxon rank sum test was used for continuous variables. Survival was estimated with the Kaplan-Meier method. One hundred three consecutive patients (53 women; mean age 64±17 years) entered the study. Fifty-one patients were randomized to the syncope unit. For the syncope unit and standard care patients, the presumptive diagnosis was established in 34 (67%) and 5 (10%) patients ( P <0.001), respectively, hospital admission was required for 22 (43%) and 51 (98%) patients ( P <0.001), and total patient-hospital days were reduced from 140 to 64. Actuarial survival was 97% and 90% ( P =0.30), and survival free from recurrent syncope was 88% and 89% ( P =0.72) at 2 years for the syncope unit and standard care groups, respectively. Conclusions— The novel syncope unit designed for this study significantly improved diagnostic yield in the emergency department and reduced hospital admission and total length of hospital stay without affecting recurrent syncope and all-cause mortality among intermediate-risk patients. Observations from the present study provide benchmark data for improving patient care and effectively utilizing healthcare resources.

ABSTRACT Intracellular calcium signaling plays a central role in cell proliferation. In leukemic cells, the calcium release‐activated calcium channels provide a major pathway for calcium entry (I CRAC ) perpetuating progression through the cell cycle. Although I CRAC is under mitochondrial regulation, targeting mitochondrial function has not been exploited to control malignant cell growth. The benzothiadiazine diazoxide, which depolarized respiration‐dependent mitochondrial membrane potential, reduced the rate of proliferation and arrested human acute leukemic T cells in the G0/G1 phase. Diazoxide did not alter cellular energetics, but rather inhibited the mitochondria‐controlled I CRAC and reduced calcium influx into tumor cells. The antiproliferative action of diazoxide was mimicked by removal of extracellular calcium or by the tyrphostin A9, an I CRAC inhibitor. Deletion of the mitochondrial genome, which encodes essential respiratory chain enzyme subunits, attenuated the inhibitory effect of diazoxide on I CRAC ‐mediated calcium influx and cell proliferation. Thus, manipulation of mitochondrial function and associated calcium signaling provides a basis for a novel anticancer strategy.—Holmuhamedov, E., Lewis, L., Bienengraeber, M., Holmuhamedova, M., Jahangir, A., Terzic, A. Suppression of human tumor cell proliferation through mitochondrial targeting. FASEB J. 16, 1010–1016 (2002)