AIM: To compare the effects of histidine-tryptophan-ketoglurate(HTK)solution, University of Wisconsin(UW)solution and St.Thomas(ST) Cardioplegia solution Ⅱ on hypothermic preservation of isolated rat hearts. METHODS: Isolated hearts from male Wistar rats were mounted on a Longendorff apparatus to estimate left ventricular end-diastolic pressure(LVEDP),left ventricular developed pressure(LVDP), rate of change of left ventricular pressure(d p /d t max ,d p /d t min ) and coronary flow(CF).Twenty-four rats were randomly divided into three groups: HTK group, UW groups and ST group.They were arrest and stored at 4℃ in each preservation solution for 6 hours. Following storage, they were reperfused and postpreservative function was measured to assess cardiac functional recovery. Frozen samples were analyzed for concentration of adenosine triphosphate. RESULTS: The concentration of adenosine triphosphate in three groups was significantly different( P

AIM: We tested the hypothesis that marrow s tr omal cells (MSCs), when implanted into self-myocardium, can undergo milieu-depen dent differentiation, express cardiomyogenic phenotypes and enhance angiogenesis and cardiac function of ischemic hearts in vivo. METHODS: In order to achieve a safe and persistent effect, we ex plored the potential of autologous MSCs transplantation. One week after myo cardial infarction induced by occlusion of left anterior descending artery, auto logous MSCs labeled with BrdU (bromodeoxyuridine) in vitro was administered intramyocardially into the infarct area of the same donor rabbits. RESULTS: By 1 months, transplanted MSCs demonstrated to be myoge nic differentiation with the expression of ?-sarcomeric actin (5C5). MSCs impla ntation significantly increased vascular density in the infarct zone and resulte d in markedly improved the left ventricular contractility. CONCLUSION: The finding indicates that autologous MSCs transplan tation may represent a promising therapeutic strategy with free of ethical conce rns and immune rejection.

AIM: To evaluate the reliability of making a research model of coronary artery stenosis and local myocardial infarction reproduced in dog by ligating canine LAD. METHODS: We disparted 30 aged healthy cross-breed dogs [(18.5?6.7) kg] into three groups. The near part of the LAD through left minimal thoracic incision was ligated to interdict 25% (group A), 50% (group B), 75% (group C) of the flux, respectively. The changes of plasma endothelium-derived factors NO, ET-1, sP-selectin and CTnT were measured before ligation and at different time points after ligation. The expression of P-selectin gene in cardiac muscle was detected by Western blotting. The segments of distal parts of the ligated LAD were cut and pathological changes of the patches of topical cardiac muscle were observed by electronic microscope. RESULTS: After ligation, NO/ET-1, P-selectin and CTnT had significant changes in group B (P

This study tested the hypothesis that controlled reperfusion with warm blood cardioplegia containing mannitol would result in more effectively improved recovery of myocardial mitochondrial function by preventing or reducing a potentially harmful component of reperfusion. Myocardial mitochondrial function was significantly depressed after 60 min reperfusion, but slightly depressed in the controlled reperfusion group. Significantly increased MDA content and decreased SOD activity were observed after 60 min reperfusion. Hearts in the controlled reperfusion group had low MDA content and might protect the activity of SOD. The- results indicate that controlled reperfusion after ischemia provides benefit in avoiding myocardial mitochondrial reperfusion injury.

AIM: To study apoptosis in heart of multiple organ dysfunction syndrome (MODS) rat at high altitude. METHODS: The two-hit model of MODS rat was used at two different altitude(1 510 m, 3 900 m). Hemorrhage was induced in Wistar rats by catheterizing the femoral artery until a mean arterial pressure was 35 mmHg and maintained for 1 hour. Rususcitation was performed with lactated Ringer′s solution at 24 h after hemorrhage, cecal ligation and puncture(CLP) was performed .Then rats were killed at 3 h,6 h,12 h and 24 h after CLP, and myocardium sample was excised and stored in liquid nitrogen. Apoptosis in heart was determined by DNA agarose gel electrophoresis, flow cytometry(FCM), transmission electron microscope(TEM) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL). RESULTS: The special ladder pattern for apoptosis was seen in myocardium sample at high altitude(3 900 m) group.The apoptotic rate in myocardium was higher in high altitude(3 900 m) group than that in lower altitude(1 510 m) group( P

The effect of myocardium subjected to 60 min ischemia and 60 min reperfusion on the level of lipid peroxides (LPO) and function of myocardial mitochondria and activity of superoxide dismutase (SOD) was studied in cat cardiopulmonary bypass. Myocardial mitochondrial function was slightly depressed after 60 min ischemia but significantly depressed after 60 min reperfusion. Increased lipid peroxides content and decreased SOD activity were observed at 60 min ischemia. After reperfusion, the SOD activity continued decreasing, but LPO elevated apparently. These results support a hypothesis that the free radicals may contribute to the myocardial mitochondrial reperfusion injury.

To test the hypothesis that the controlled reperfusion of warm blood cardioplegiacontaining mannitol would result in more effectively improved recovery of myocardial function by prevent-ing or reducing a potentially harmful component of reperfusion. Methods: Thirty-two cats were divided in-to four groups. Group Ⅰwas not subjected to ischemia or reperfusion injury. Group Ⅱ was subjected to60 min hypothermic ischemia. Group Ⅲwas subjected to 60 min hypothermic ischemia and 60 min reperfu-sion. Group Ⅳ was controlled reperfusion with warm blood cardioplegia containing mannitol. Results:Myocardial functlon was significantly depressed after 60 min reperfusion- Increased myocardial water con-tent and low ATP c0ntent were observed also. Controlled reperfusion with warm bl0od cardioplegia con-taining mannitol was helpful to improve the recovery of myocardial function and ATP content, and to re-duce the myocardial water content. Conclusion: These results indicate that controlled reperfusion after is-chemia provides benefit in avoiding myocardium from reperfusion injury.

This study was directed at estimating the value of platelet count in the course of in-vitro hemolytic tests by roller pump. Five paired in-vitro tests were conducted using the POLYSTAN pump(group A) and COBE pump(group B). The pumps ran 16 hours. The samples for platelet count and plasma-free hemoglobin were taken before pumping, and every 2 hours after 4 hours of pumping. The 2 groups' platelet count and plasma-free hemoglobin levels were found to be linearly increasing with the hours of pumping and linear regression analysis showed the platelet count and plasma-free hemoglobin were positively correlated. These data suggested that platelet count could be used as an index in evaluating the in-vitro hemolytic properties of blood pumps.
Assisted Circulation ; Hemoglobins ; analysis ; Hemolysis ; Humans ; Linear Models ; Platelet Count

UNLABELLEDTo observe the antithrambotic property of a new prosthetic made double bileaflet valve of all-pyrolytic carbon.

METHODFifteen sheeps underwent mitral valve replacement (MVR) with this new mechanical valve. Each animal was placed on cardiopulmonary bypass. All of the sheep were given in an anticoagulation protocol and followed for three months. Final studies were performed on all animals surviving for more than 12 weeks.

RESULTTen sheeps died within 48 h after operation, five sheeps survived. The long-term survivors were killed forautopsies, two sheeps were killed in the 1st week after operation, one in 12th weeks and two in 2.5 years. Pathological examination of 10 sheeps which died early after operation revealed that there was no either evidence of thromboembotic phenomenon, or any failures of the mechanical valve. Autopsy studies in the five long-term survivors revealed that the sewing ring was covered by a thin layer of microthrombi consisted most of platelets and fibrin in 1th week after operation. The sewing rings was covered by a tissue layer, with partial organized micro thrombi and endothelialization in 12th weeks after the operation. Two and half years after operation, the complete endothelialization presented around the sewing ring without restriction of bileaflet motion. The tissue ingrowth tends to stop at the pyrolytic carbon-fabric interface on both surfaces of left atrium and ventricle. This study demonstrated that the new prosthetic heart valve had not promoted thrombosis and thrombembolism.

Animals ; Biocompatible Materials ; Carbon ; Female ; Heart Valve Prosthesis ; Heart Valve Prosthesis Implantation ; Male ; Materials Testing ; Sheep ; Thrombosis ; prevention & control

To observe the erythrocyte fragility and morphological changes of erythrocytes caused by roller pump. Ten tests were divided into two groups, Polystan pediatric pump group A (n = 5) and COBE pump group B (n = 5). Ten whole blood samples (each 400 ml) were circulated in the roller pump for 16 h. Erythrocyte fragility and free hemoglobin were measured before pumping and at every 2 hours during pumping. The possible morphological changes of erythrocytes caused by roller pump were observed by scanning electron microscope. The electron microscopic observation was made before pumping and at every 4 hours throughout pumping. Results showed that the erythrocyte fragility of two groups was not increased during a long period of pumping. The number of acanthocytes of two groups was 1.77/1.81% in the samples before pumping and 6.12/7.13, 9.18/8.73, 13.21/12.89, 16.53/17.21% at 4 h, 8 h, 12 h, and 16 h respectively. The free hemoglobin level of two groups was increased linearly during a long duration of pumping and the index of hemolysis of two groups was 0.296 mg/L/h and 0.3993 mg/L/h respectively. The result shows: 1. the erythrocyte fragility was not increased during a long period of pumping; 2. the erythrocyte membrane was injured or broken by roller pump directly; 3. the morphological changes of erythrocytes would be the basis of post operative hemolysis.
Erythrocyte Deformability ; Heart-Lung Machine ; adverse effects ; Hemoglobins ; analysis ; Hemolysis ; Humans ; In Vitro Techniques ; Osmotic Fragility ; Time Factors