Objective To investigate if mitochondrial KATP channels are involved in the cardioprotective effects of astragalus membranaceus in immature rabbit hearts. Methods Twenty-four New Zealand white rabbits of both sexes aged 14-21 days weighing 300-350 g were anesthetized and heparinized. The hearts were rapidly removed after thoracotomy and mounted on a Langendorff apparatus via ascending aorta and perfused with oxygenated (95% O2-5% CO2) Krebs-Hensleit buffer (KHB) solution at 60 cm H2O (perfusion pressure) and 38 ℃ . A fluid-filled latex balloon was inserted into left ventricle via left atrium for measurement of left ventricular developed pressure ( LVDP) , Global myocardial ischemia was induced by suspension of perfusion for 30 min followed by 45 min reperfusion. The animals were randomly divided into 3 groups with 8 animals in each group : group A control;group B astragalus and group C astragalus +- 5-HD (a selective inhibitor of the mitochondrial KATP channel). In group B the hearts were perfused with astragalus 40 g? L-1 for 15 min before ischemia. In group C the hearts were perfused with 5-HD 100?mol?L-1 for 5 min followed by 10 min astragalus perfusion before ischemia. In control group the hearts were perfused with only KHB before ischemia. Coronary flow (CF), HR, LVDP and ? dp/dtmax, were measured at 5, 10, 15, 30 and 45 min of reperfusion and recorded. Coronary effluent was collected at 10 min of reperfusion for determination of CK-MB, LDH and CK levels . At the end of 45 min reperfusion the isolated heart was removed for determination of myocardial ATP and iNOS levels and electron microscopic examination.Results In astragalus group (B) LVDP ? dp/dtmax and CF recovered significantly better and myocardial ATP content was significantly higher as compared with group A and C (P

Objective: To investigate the effects of adrenomedullin1-50 (Adm1-50) on vascular cell adhesion molecule-1 (VCAM-1) expression in isolated rat heart. Methods: Twenty-four male Sprague-Dawley rat, weighting 300 to 350g, were randomly divided into A, B, C, D group (n=6 for each group). The isolated rat hearts were perfused in a Langendorff mode for 20 min and followed by 60 min of global ischemia. Then, all groups were reperfused with Kerbs-Henseleit bicarbonate for 60 min, but group B, C, D were perfused with buffer in the presence of Adm1-50 10-9mol/L, 10-8mol/L, and 10-7mol/L respectively for 15 min after the onset of reperfusion. The post-ischemic change of creatine kinase-isoenzyme (CK-MB) in coronary effluent and the expression of myocardial VCAM-1 mRNA were measured. Results: After I/R, Adm1-50 dose-dependently decreased the expression of VCAM-1 and the CK-MB activity, The ratio of VCAM-1/GAPDH mRNA were 1 20?0 52, 1 10?0 45, 0 60?0 31, 0 50?0 36 for group A, B, C, D, respectively (P

Objective: To observe the changes of circulating endothelial cells (CEC) and endothelin(ET) and the effect of aprotinin on them during open heart surgery. Method:Twenty patients undergoing valve replacement were divided into two groups,control group(n=10) in which and protinin group (n=10), 4000000 unit aprotinin were given during cardiopulmonary bypass (CPB), Blood samples were collected before operation,pre-CPB,15,30 and 60 minute following CPB and 1st, 3rd, 5th day after operation. Result: As compared to pre-CPB in control group,CEC and ET levels increased during CPB and returned the normal after operation. In aprotinin group,the tendency of change was same,but CEC and ET levels were higher in control group than in aprotinin group during CPB. Conclusion:There are endothelial ceils damaging and ET significant increasing during CPB,while aprotinin can ameliorate this situation.

Objective To probe the effects of hypothermia and St Thomas Hospital Ⅱ cardioplegia on immature myocardium.Methods To observe the change of hemodynamics,myocardial enzyme in the coronary effluent and myocardial biochemistry of the perfused immature rabbit heart in vitro after two or four hours ischemia at 14 degrees centigrade.Results There were no significant differences in post ischemic hemodynamics,myocardial enzyme in the coronary effluent and myocardial biochemical parameters of the perfused immature heart The myocardial protective effect provided by St.Thomas Hospital Ⅱ cardioplegia was worsen than that of hypothermia alone,marked by the elevated myocardial enzyme leakage and the decreased hemodynamics.Single dose perfusion was better than multi dose perfusion by characteristics of decreased enzyme leakege and good post ischemic hemodynamics.Conclusions Hypothermia alone can provide immature heart with satisfactory myocardial protection.St.Thomas Hospital Ⅱ cardioplegia can not afford good myocardial protection to immature heart and enhance the myocardial protective effect provided by hypothermia.The myocardial protection effect is better provided by single dose perfusion than by multi dose perfusion

Objective Protection afforded by ischemic preconditioning (IPC) against myocardial ischemia in adult heart has been investigated. This study was designed to examine the effects of IPC on myocardial tolerance to ischemia in immature hearts.Methods The aorta of isolated immature rabbit heart (14-21d old) was connected to Langendorff preparation within 30 s after excision. The hearts were perfused with oxygenated (95%O 2:5%CO 2) Krebs-Henseleit buffer(KHB) at 60 cmH 2O. 16 immature rabbit hearts were equally divided into 2 groups: control group and IPC group. In IPC group the hearts were first subjected to IPC stimulus consisting of 5 min global ischemia followed by 10 min reperfusion. The hearts in both groups were made globally ischemic for 30 min(no perfusion) followed by 40 min reperfusion. At the end of 40 min reperfusion the hearts were harvested for ATP analysis. The coronary flow(C), HR, left ventricle developed pressure(LVDP) and ?dp/dt were monitored and recorded before ischemia and at 5,10,20,30 and 40 min of reperfusion, and calculated as % of pre-ischemia levels. Coronary flow was collected before and after reperfusion for CK-MB determination.Results There were no statistically significant differences in the four parameters between the two groups. Arrhythmia scores were also comparable betweeen the two groups. The CK-MB leakage in IPC group was increased but not significantly different from that in control group. The ATP levels of myocardium at the end of reperfusion was significantly lower than that in the control group [(123.85?17.42)?g/g versus (167.21?16.53)?g/g].Conclusions IPC can not protect immature rabbit hearts from ischemia-reperfusion injury. On the contrary it may lead to myocardial injury due to more energy consumption.

Objective To investigate whether ischemic preconditioning( IPC) could protect against ischemia-reperfusion injury in immature rabbit heart and the role of KATP channel in the mechanism of myocardial protection. Methods New Zealand rabbits aged 14-21 days weighing 220-280g were used. The animals were anesthetized and heparinized. Chest was opened and heart was quickly removed and aorta was connected to Langendorff preparation within 30 s. The hearts were perfused with Krebs-Henseleit buffer balanced with gas mixture(O2: CO2 = 95% : 5% ) at 60cmH2O2(perfusion pressure) . IPC consisted of 5 mm global ischimia plus 10 mm reperfusion. Glibenclamide was used as KATP channel blocker. Cardiac arrest was induced with cold(4℃ ) St Thomas Ⅱ cardioplegic solution and heart was made globally ischemic by withholding perfusion for 45 mm followed by 40 mm reperfusion. Thirty immature rabbit hearts were randomly divided into four groups: group Ⅰ( n= 9 control) was subjected to ischemia-reperfusion only; groupⅡ(n= 9 IPC + ischemia-reperfusion); group Ⅲ(n = 6 glibenclamide + ischemia-reperfusion) and group Ⅳ( n= 6 glibenclamide + IPC + ischemia-reperfusion) . Coronary flow(CF), HR, left ventricle developed pressure( LVDP) and ? dP/dt max were monitored before ischemia/IPC/glibenclamide( baseline value) and 5, 10, 20 and 40 mm after reperfusion and were expressed as percentage of their baseline values. Arrhythmia scores were recorded. Coronary effluent was collected at 10 miii after reperfusion was started for determination of CK-MB level. At the end of reperfusion 200mg myocardium was taken from apex for determination of ATP content. Results The group Ⅱ(IPC group) showed best results. The recovery of CF, HR, LVDP and ?dp/dt max, was best among the four groups. The incidence of arrhythmia was low and less CK-MB leaked out. Myocardial ATP content was better preserved. Pretreatment with glibenclamide completely abolished the myocardial protection provided by IPC but did not affect ischemiareperfusion injury. Conclusions IPC can protect against ischemia-reperfusion injury in immature rabbit bean. Activation of KATh channel is involved in the mechanism of myocardial protection of IPC.

Objective To summarize the effective managements of cardiopulmonary bypass (CPB) duing open heart surgery in the elderly patients by comparing with that of the non-elderly groups. Methods Pre-operative common data and the managements for 84 elderly patients during the cardiopulmonary bypass from January 1998 to June 2000 were analyzed retrospectively, and the same data of 80 non-elderly patients(40-60 years old) who underwent CABG during the same period were also randomly selected and compared. Results The elderly patients were usually combined with hypertension, diabeties, chronic kindney failure and abnormal pulmonary function. The average time for CPB and clamping time for the ascending aorta were (115.6?27.0)min and (80.4?32.2)min, respectively. The average lowest nasopharyngeal and anal temperature was (29.8?1.4)℃ and (30.7?0.8)℃, respectively, showing no significant difference comaparing with those of the non-elderly patients. There was significant difference between the two groups in the transfusion of shed blood(P

Objective To investigate whether diazoxide preconditioning can exert protective effect on myocardium against ischemia-reperfusion injury in immature rabbits and the possible mechanism. Methods Twenty-one healthy 3-4 week old white rabbits of either sex were randomly divided into 3 groups : group Ⅰ control ( n = 8) ; group Ⅱ diazoxide preconditioning ( n = 8) and group Ⅲ diazoxide + 5-HD preconditioning ( n = 5) . The animals were anesthetized with intraperitoneal pentobarbital 50 mg?kg-1 and heparized (150 IU?kg-1). The hearts were excised and connected to Langendorff apparatus and passively perfused with normothermic (37℃), oxygenated (95% O2 , 5% CO2) Krebs-Henseleit buffer (KHB) at a constant perfusion pressure of 70cmH2O. A latex balloon was inserted via left atrium into left ventricle and filled with water. The left ventricular end-diastolic pressure (LVEDP) was maintained at 10 mm Hg. In group I cardiac arrest was induced with St Thomas Ⅱ solution after the heart was perfused with KHB for 30 min. In group 11 after being perfused with KHB for 15 min, the hearts were perfused with diazoxide 100?mol?L-1 for 5 min followed by 10 min wash-out with KHB , then cardiac arrest was induced as in group Ⅰ . In group Ⅲ after being perfused with KHB for 15 min, the hearts were perfused with diazoxide 100?mol?L-1 and 5-HD 100?mol?L-1 for 5 min, followed by 10 min wash-out with KHB, then the cardiac arrest was induced as in group Ⅰ and Ⅱ . All hearts were subjected to 30 min ischemia followed by 45 min reperfusion after cardiac arrest. Coronary flow (CF), HR, left ventricular developed pressure (LVDP) and dp / dt max were measured after the hearts were perfused with KHB for 15 min (baseline) and at 5, 10, 15, 30, 45 min after reperfusion was resumed. Coronary effluent was collected at 5 min after reperfusion was resumed for determination of myocardial enzymes, CK, LDH and AST. At the end of experiment myocardial specimen was obtained for determination of ATP content and ultrastructure examination. Results There was no significant difference in the baseline hemodynamic parameters among the three groups. The rates of recovery of LVDP and ? dp / dt max after reperfusion were significantly higher in group Ⅱ than those in group I and Ⅲ ( P 0.05 ) , Conclusion Diazoxide can protect myocardium from ischemia-reperfusion injury by opening the mitochondrial KATP channel in immature rabbits.

BACKGROUND: Mortality related to cardiopulmonary bypass can be lowered by intra-operative monitoring system.Monitoring liquid level and pressure is extremely indispensable for examination of cardiopulmonary bypass(CPB).OBJECTIVE: To design a CPB safety system including an arterial line pressure monitor and low-level sensor,and to evaluate its safety and effects in clinical settings.METHODS: The safety system was composed of pressure transducer,photoelectric transmitter,photoelectric detector,core controller,and liquid crystal display.The principles of reflection and refraction were applied to the design of level sensor.The pressure measurements were converted into electronic signals and processed.According to two principles above-mentioned,fluid level detector and pressure monitor were designed.Thirty patients with the age of 1-75 years receiving cardiac surgery with cardiopulmonary bypass were enrolled.The arterial line pressure at different pump flows was measured and the alarm function of the level sensor was also validated.RESULTS AND CONCLUSION: Cardiopulmonary bypass arterial line pressure increased with the pump flow.Arterial line pressure detected by HZ-01-A safety system also increased with the pump flow increasing,which was highly related to the pump pressure.HZ-01-A safety system could alarm when the arterial line pressure and reservoir level exceeded the pre-determined thresholds.HZ-01-A safety system could be safely and effectively applied to clinical cardiopulmonary bypass and improve bypass safety by accurately detecting the pressure and reservoir level.

BACKGROUND: The blood oxygen saturation is an important physiological parameter of human hfe; it can be affected by multiple factors due to the imbalance of oxygen supply and consumption, and consequently, the normal physical metabolism is affected. The existing manufacturing techniques are complex and are used with higher demands. OBJECTIVE: To investigate the accuracy of the novel reflecting oximeter designed on the basis of reflecting principle in monitoring the variance of blood oxygen saturation with the change of its concentration. DESIGN: To introduce the structure, working principle and design of the reflecting oximeter and make comparative study with adult rabbits as the subjects. SETTING: Cardiopolmonary Bypass Department of Cardiovascular disease hospital of the Chinese Academy of MedicalSciences. MATERIALS: The study was performed at the Departments of Anesthesiology and Cardiopulmonary Bypass of the Cardiovascular Disease Hospital,Chinese Academy of Medical Sciences from August to October in 2001.Ten adult rabbits were selected. METHODS: The oximeter consists of a converter, a driver, a central processing mould and liquid-crystal monitor. It is characterized by the onethree optical cable connected with reflecting probe, postcentral management system and digital displayer. This oxmeter was developed basing on the basis of fixed relationship between blood oxygen saturation and radiant absorbency (or reflecting). In this study,cardiovascular-pulmonary bypass was established on rabbits that were then exposed to oxygen and NO mixture supply of different concentrations,and then the corresponding blood oxygen saturations were determined with the new oximeter and compared with series-wound Baite saturation meter and blood-gas analysis. MAIN OUTCOME MEASURES: The blood oxygen saturation at different concentrations determined with the reflecting oximeter and Baite saturation meter. RESULTS: At the same oxygen concentration, the blood oxygen saturation determined with the new measure was not significantly different from that determined with Baite blood oxygen saturation meter(P＞0.05 ). CONCLUSION: The variance of blood oxygen saturation with the change of oxygen concentration can be detected by the reflecting oximeter with the result similar to that by Baite blood oxygen saturation meter.