Effects of glibenclamide, glimepiride, and gliclazide on ischemic preconditioning in rat heart / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To compare the influence of different sulfonylureas on the myocardial protection effect of ischemic preconditioning (IPC) in isolated rat hearts, and ATP-sensitive potassium channel current (IK(ATP)) of rat ventricular myocytes.</p><p><b>METHODS</b>Isolated Langendorff perfused rat hearts were randomly assigned to five groups: (1) control group, (2) IPC group, (3) IPC + glibenclamide (GLB, 10 micromol/L) group, (4) IPC + glimepiride (GLM, 10 micromol/L) group, (5) IPC + gliclazide (GLC, 50 micromol/L) group. IPC was defined as 3 cycles of 5-minute zero-flow global ischemia followed by 5-minute reperfusion. The haemodynamic parameters and the infarct size of each isolated heart were recorded. And the sarcolemmal IK(ATP) of dissociated ventricular myocytes reperfused with 10 micromol/L GLB, 1 micromol/L GLM, and 1 micromol/L GLC was recorded with single-pipette whole-cell voltage clamp under simulated ischemic condition.</p><p><b>RESULTS</b>The infarct sizes of rat hearts in IPC (23.7% +/- 1.3%), IPC + GLM (24.6% +/- 1.0%), and IPC + GLC (33.1% +/- 1.3%) groups were all significantly smaller than that in control group (43.3% +/- 1.8%; P < 0.01, n = 6). The infarct size of rat hearts in IPC + GLB group (40.4% +/- 1.4%) was significantly larger than that in IPC group (P < 0.01, n=6). Under simulated ischemic condition, GLB (10 micromol/L) decreased IK(ATP) from 20.65 +/- 7.80 to 9.09 +/- 0.10 pA/pF (P < 0.01, n=6), GLM (1 micromol/L) did not significantly inhibit IK(ATP) (n=6), and GLC (1 micromol/L) decreased IK(ATP) from 16.73 +/- 0.97 to 11. 18 +/- 3.56 pA/pF (P < 0.05, n=6).</p><p><b>CONCLUSIONS</b>GLM has less effect on myocardial protection of IPC than GLB and GLC. Blockage of sarcolemmal ATP-sensitive potassium channels in myocardium might play an important role in diminishing IPC-induced protection of GLM, GLB, and GLC.</p>

Treatment with oral sildenafil in patients with severe pulmonary hypertension after open heart operations / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate the clinical effects of treatment with oral sildenafil on severe pulmonary hypertension after cardiac surgery.</p><p><b>METHODS</b>From September 2002 to January 2005, oral sildenafil was added to the treatment regime in 27 cases of severe pulmonary hypertension after cardiac surgery. All these cases were given general treatments including intravenous prostaglandin E1 and inhalation of nitric oxide before the use of sildenafil, which did not show obvious effects on decreasing pulmonary pressure. Then a combined treatment [general treatment plus oral sildenafil (1-2 mg/kg, q8h; Pfizer Ltd)] was instituted. Pulmonary artery pressure, systolic pulmonary artery pressure/systolic systemic blood pressure (Pp/Ps) were measured before and every hour after adding sildenafil.</p><p><b>RESULTS</b>One hour after adding sildenafil, the patients' pulmonary artery pressure decreased remarkably (P < 0.01) with no adverse effects on systematic artery pressure. SO(2) and PaO(2) of all cases improved respectively (P < 0.05). One or two days later, the patients' hemodynamics were stable and some patients stopped inhaling nitric oxide and the dosage of prostaglandin E1 decreased. 25 cases stopped use of ventilator and were discharged safely. 2 cases died of multiple organ dysfunction.</p><p><b>CONCLUSION</b>Sildenafil is a highly selective and effective pulmonary hypertension vasodilator, which can be given for the treatment of pulmonary hypertension after cardiac surgery.</p>