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Z L Cao

Publications and source records attributed to Z L Cao.

14 recordsLinked to original sources
PubMed2000

Ulinastatin attenuates reperfusion injury in the isolated blood-perfused rabbit heart.

BACKGROUND: Ventricular dysfunction after long cardioplegic arrest has been observed in cardiac operations. Urinary trypsin inhibitor, also called ulinastatin, may attenuate myocardial ischemia-reperfusion injury. The present study was designed to determine the protective efficacy of ulinastatin in blood-perfused parabiotic isolated rabbit hearts as a surgically relevant model with long (4-hour) cardioplegic arrest. METHODS: Each isolated rabbit heart, with a latex balloon inserted in the left ventricle, was parabiotically blood-perfused using a modified Langendorff column. The left ventricular developed pressure, rate of pressure development, and coronary flow with a left ventricular end-diastolic pressure of 10 mm Hg were measured before ischemia and 15, 30, 45, and 60 minutes after reperfusion began (control, n = 10). Ulinastatin (15,000 U/kg) was administered to the support animal just before reperfusion began (group U-1, n = 10) or at the beginning of the extracorporeal circulation and readministered before reperfusion (group U-2, n = 10). The endothelium of the coronary artery was observed by scanning electron microscopy to evaluate the extent of endothelial ischemia-reperfusion injury. RESULTS: Ulinastatin enhanced the recovery of developed pressure in both the U-1 (p<0.05) and U-2 (p < 0.01) groups compared with the control group. Although ulinastatin given just before reperfusion (group U-1) did not enhance the recovery of the rate of pressure development or the coronary flow compared with the control, earlier administration did improve the recovery of the rate of pressure development compared with the control (U-2, p<0.05), and there was improvement of the recovery of coronary flow after 60 minutes of reperfusion (U-2, p<0.05). Scanning electron microscopy showed that ulinastatin had ameliorated coronary endothelial damage. CONCLUSIONS: Ulinastatin improved functional recovery after long cardioplegic arrest and reduced coronary endothelial injury. Administration of ulinastatin at the beginning of cardiopulmonary bypass and just before reperfusion may be useful clinically in cases requiring prolonged aortic cross-clamping.

Animals↗
PubMed2000

Leukocyte-depleted reperfusion after long cardioplegic arrest attenuates ischemia-reperfusion injury of the coronary endothelium and myocardium in rabbit hearts.

OBJECTIVE: Cardiopulmonary bypass activates leukocytes, which should injure the coronary endothelium and myocardium during reperfusion especially after long cardioplegic arrest with long cardiopulmonary bypass time. The present study was designed to determine the protective efficacy of leukocyte-depleted reperfusion in blood-perfused parabiotic isolated rabbit hearts as a surgically relevant model with long cardioplegic arrest. METHODS: Each isolated rabbit heart, with a latex balloon inserted in the left ventricle, was parabiotically blood-perfused using a modified Langendorff column. The left ventricular developed pressure (DP), rate of pressure development (dP/dT), and coronary flow with a left ventricular end-diastolic pressure of 10 mmHg were measured before ischemia and after 15, 30, 45, and 60 min reperfusion after 4 h cardioplegic arrest kept at 20 degrees C (control, n=10). Leukocyte-depleted reperfusion was done in the test group (n=10). The endothelium of the coronary artery was observed by scanning electron microscopy (SEM) with percent injured area of endothelial cells measured to evaluate the extent of endothelial ischemia-reperfusion injury. RESULTS: The control hearts showed 53.3, 54.3, 48.4, and 39.0% recovery of DP compared to the pre-ischemia baseline data at 15, 30, 45, and 60 min after reperfusion began respectively. Leukocyte-depleted reperfusion enhanced the recovery of DP at 45 min (81.3%, P=0.0021) and 60 min (85.8%, P=0.0005) after reperfusion compared with that in the control group. The control hearts revealed 58.8%, 59.8%, 52.6%, and 43.4% recovery of dP/dT compared to the pre-ischemia baseline data at 15, 30, 45, and 60 min after reperfusion began, respectively. Leukocyte-depleted reperfusion also enhanced the recovery of dP/dT at 45 min (93.2%, P=0.0071) and 60 min (98.8%, P=0.0011) after reperfusion compared with that in the control group. There was also improvement of the recovery of coronary flow by leukocyte-depleted reperfusion (97.2%) compared with that in the control group (58.3%) after 60 min reperfusion (P=0.0121). Scanning electron microscopy showed that 69. 7% of coronary endothelial cells were morphologically injured in the control group. In contrast, leukocyte-depleted reperfusion prevented the extent of coronary endothelial damage with less injured area (0. 5%, P=0.0002). CONCLUSIONS: Leukocyte-depleted reperfusion improved functional recovery with reduced coronary endothelial injury after long cardioplegic arrest.

Animals↗
PubMed2000

Experimental use of a compact centrifugal pump and membrane oxygenator as a cardiopulmonary support system.

Compactness and high performance are the most important requirements for a cardiopulmonary support system. The Nikkiso (HPM-15) centrifugal pump is the smallest (priming volume; 25 ml, impeller diameter; 50 mm) in clinically available centrifugal pumps. The Kuraray Menox (AL-2000) membrane oxygenator, made of double-layer polyolefin hollow fiber, has a minimum priming volume (80 ml) and a low pressure loss (65 mm Hg at 2.0 L/min of blood flow) compared with other oxygenators. The aim of this study was to evaluate the performance of the most compact cardiopulmonary support system (total priming volume: 125 ml) in animal experiments. The cardiopulmonary bypass was constructed in a canine model with the Nikkiso pump and Menox oxygenator in comparison with a conventional cardiopulmonary support system. The partial cardiopulmonary bypass was performed for 4 h to evaluate the gas exchange ability, blood trauma, serum leakage, hemodynamics, and blood coagulative parameters. The postoperative plasma free hemoglobin level of the compact cardiopulmonary system was 29.5 +/- 10.21 mg/dl (mean +/- SD), which was lower than that of the conventional cardiopulmonary system, 48.75 +/- 27.39 mg/dl (mean +/- SD). This compact cardiopulmonary system provided the advantage in terms of reduction of the priming volume and less blood damage. These results suggested the possibility of miniaturization for the cardiopulmonary bypass support system in open-heart surgery in the near future.

Animals↗
PubMed1999

Does dilatation of the sinotubular junction cause aortic regurgitation?

BACKGROUND: Some patients develop aortic regurgitation (AR) in association with dilatation of the sinotubular junction (STJ), despite having normal aortic valve. However, the relationship between dilatation of the STJ and AR is unclear. METHODS: Canine hearts and aortas were isolated. A suture was placed in each commissure and in the sinus of Valsalva at the STJ. These interrupted sutures were drawn horizontally, and strain on the sutures was varied. The sites of the retracted sutures were changed to various positions, and the opening and closing of the aortic valve was observed endoscopically. A beating heart model was used to observe changes in aortic valve function during mechanical retraction of the commissures or sinuses. RESULTS: Opening area of the valve increased when strain on all sutures or commissures was increased. When strain was increased on the sinus alone, coaptation of the valve was not affected. CONCLUSION: We observed endoscopically that mechanical dilatation of the STJ causes AR. These findings suggest that the principal cause of AR associated with dilatation of the STJ is outward deviation of the commissure.

Animals↗
PubMed1998

Veno-right ventricular extracorporeal membrane oxygenation for thoracic surgery: an experimental study in dogs.

BACKGROUND: Although the indications for extracorporeal membrane oxygenation (ECMO) have been extended, ECMO has yet to be used as a respiratory support system during thoracic surgery. The purpose of this experimental study was to investigate whether veno-right ventricular (veno-RV) ECMO can be used for thoracic surgery without mechanical ventilation. METHODS: Acute experimental study: Veno-RV ECMO as total lung support was maintained for 60 min without mechanical ventilation in six dogs. A venous drainage cannula was inserted in the superior cavoatrial junction through the right femoral vein and a venous return cannula was inserted in the right ventricle through the right jugular vein. The veno-RV ECMO system comprised a centrifugal pump and membrane oxygenator. Survival model: After veno-RV ECMO had been established in three dogs, a two-ring thoracic tracheal segment was resected and the tracheal ends were anastomosed by video-assisted thoracic surgery without ventilation. RESULTS: In the acute study, when the veno-RV ECMO flow was maintained at 100 mL/kg/min, all six dogs remained hemodynamically stable and the arterial oxygen saturation was maintained at more than 98%, despite total lung collapse. In the survival study, all three dogs made an uneventful postoperative recovery. CONCLUSION: Video-assisted tracheal surgery can be performed without conventional respiratory support. Veno-RV ECMO as total lung support may become an alternative respiratory management device for thoracic surgery.

Anastomosis, Surgical↗
PubMed1998

[Does dilatation of the sinotubular junction cause aortic regurgitation?: the use of the experimental model and preliminary result].

This study investigated the mechanism of aortic regurgitation caused by dilatation of the sinotubular junction. The canine model of dilatation of the sinotubular junction was used to observe coaptation of the aortic valve using direct imaging by endoscopy. Five adult mongrel dogs (body weight: 20-25 kg) were anesthetized and their hearts and thoracic aortas were extracted en bloc. Aortotomy was performed and an interrupted horizontal mattress suture was placed in each commissure and each sinus of Valsalva at the level of the sinotubular junction. The heart and thoracic aorta were fixed on a table and the interrupted sutures were drawn horizontally. As a result, the aorta of the junction level was dilated. Strain of the interrupted sutures were changed by weights of 20, 25, 50, 70 and 100 points (1 point = 3.5 g). The sites of the retracted sutures were the three commissures and three sinuses of Valsalva. With increased strain of the sutures, the opening of the aortic valve was exaggerated when drawing was done on either all sutures or the commissures. When drawing was done only on the three sinuses of Valsalva, coaptation of the aortic valve was uninterrupted. This study showed that dilatation of the sinotubular junction causes aortic regurgitation, which is mainly due to the outward deviation of the commissures.

Animals↗
PubMed1997

Veno-right ventricle bypass as a lung support system during pulmonary surgery without ventilation.

A special lung support technique is required during carinal or tracheal surgery Veno-venous extracorporeal membrane oxygenation (ECMO) has become an accepted technique for temporary lung support. Therefore, the purpose of our experiments was to evaluate the effect of veno-venous ECMO (veno-right ventricle bypass) without ventilatory support. In five mongrel dogs, two venous drainage cannula were inserted into the superior vena cava through the right jugular vein and the inferior vena cava through the right femoral vein. In addition, a venous return cannula was inserted into the right ventricle (RV) through the right jugular vein. The veno-right ventricle (veno-RV) bypass system was composed of a centrifugal pump and membrane oxygenator; pump flow was maintained at 88 +/- 14 ml/kg/min. Excellent hemodynamics and good oxygenation were obtained. On the basis of these results, we conclude that veno-RV bypass may be used as lung support during pulmonary surgery even though the native lung is not ventilated during the veno-RV bypass procedure.

Animals↗
PubMed1996

Comparative hemolysis study of clinically available centrifugal pumps.

Centrifugal pumps have become important devices for cardiopulmonary bypass and circulatory assistance. Five types of centrifugal pumps are clinically available in Japan. To evaluate the blood trauma caused by centrifugal pumps, a comparative hemolysis study was performed under identical conditions. In vitro hemolysis test circuits were constructed to operate the BioMedicus BP-80 (Medtronic, BioMedicus), Sarns Delphin (Sarns/3M Healthcare), Isoflow (St. Jude Medical [SJM]), HPM-15 (Nikkiso), and Capiox CX-SP45 (Terumo). The hemolysis test loop consisted of two 1.5 m lengths of polyvinyl chloride tubing with a 3/8-inch internal diameter, a reservoir with a sampling port, and a pump head. All pumps were set to flow at 6 L/min against the total pressure head of 120 mm Hg. Experiments were conducted simultaneously for 6 h at room temperature (21 degrees C) with fresh bovine blood. Blood samples for plasma-free hemoglobin testing were taken, and the change in temperature at the pump outlet port was measured during the experiment. The mean pump rotational speeds were 1,570, 1,374, 1,438, 1,944, and 1,296 rpm, and the normalized indexes of hemolysis were 0.00070, 0.00745, 0.00096, 0.00066, 0.00090 g/100 L for the BP-80, Sarns, SJM, Nikkiso, and Terumo pumps, respectively. The change in temperature at the pump outlet port was the least for the Nikkiso pump (1.8 degrees C) and the most with the SJM pump (3.8 degrees C). This study showed that there is no relationship between the pump rotational speed (rpm) and the normalized index of hemolysis in 5 types of centrifugal pumps. The pump design and number of impellers could be more notable factors in blood damage.

Blood Flow Velocity↗
PubMed1991

[The effect of Bulbus allii on precancerous lesions of the esophagus due to N-methyl-N-amylnitrosamine in rats].

In so much as precancerous lesions of the esophagus are a stage that must pass in the course of formation of carcinoma of the esophagus, inhibiting its occurrence is an important measure in the prevention of esophageal. The test was carried out in 84 Wistar rats of both sexes randomly divided into 2 groups, one group fed with 50% aqueous extract of Bulbus allii and the other as control. After 105th day of experiment, results showed that Bulbus allii inhibited significantly precancerous lesions of the esophagus due to N-methyl-N-amyl-nitrosamine (P less than 0.05) increases of the splenic index (P less than 0.001) in rate and the percentage of peripheral T-lymphocyte (P less than 0.01) in rats. The results suggested that Bulbus allii had a preventive action against carcinoma of the esophagus, which could be attributed to increasing the immunity.

Animals↗
PubMed1989

[Relationship between HBcAg in the liver and mechanisms of chronic type B hepatitis HBVM in serum].

We detected the presence and distribution of HBcAg in the liver by immunohistochemistry (ABC method) and the presence of HBV-DNA in serum (spot hybridization) and anti-HBe in serum (ELISA) from 59 cases of hepatitis B hospitalized in our hospital, including 47 cases of CAH, 5 cases of CPH, and 7 cases of subacute fulminant hepatitis. 1. HBcAg in the liver was detected in 25 out of 47 cases (53%) of CAH, in 2 out of 5 cases of CPH and in 4 out of 7 cases of subacute fulminant hepatitis. The total percentage was 53% (31/59). 2. There was no positive correlation between HBV replication activity and liver disease activity (P greater than 0.05). Our results did not support the hypothesis that suggests a direct cytopathic effect of HBV. Oppositely, the fact was that the presence, the amount and the patterns of HBcAg in the liver, and the presence of HBV-DNA in serum were predominant in mild CAH compared with those in severe CAH, predominant in CAH without cirrhosis compared with those in CAH with cirrhosis. There was a tendency of inverse correlation between HBV replication activity and liver disease activity. The results above were in line with the concept that HBcAg expressed on the surface of infected hepatocytes may be relevant target for T lymphocyte cytotoxicity. The results have suggested that an immune response to HBV is present, leading to the destruction of most infected cells. 3. There was a positive correlation between HBV-DNA in serum and HBcAg in the liver (P less than 0.005), indicating that HBV-DNA in serum can represent HBV replication.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA, Viral↗
PubMed1989

[Correlation between hepatic microcirculation ultrastructural changes and hepatic dysfunction in chronic hepatitis B].

The author observed the ultrastructural changes of hepatic microcirculation and the function of the liver in 41 cases with chronic hepatitis B confirmed histologically. The main ultrastructural changes found in patients were swelling of the endothelium of hepatic sinusoids, hyperplasia of Kupffer cells and decrease of fenestrae in the endothelium. Proliferation of monocytes and fat-storing cells was also found in the lumina of hepatic sinusoids and space of hepatocytes and perisinusoid. The basement membrane in hepatic sinusoids and the base of hepatocytes were formed in the patients with marked pathologic changes of the liver, especially in CAH with cirrhosis. The observations also showed that whatever extent of hepatic microcirculation changes, all of them had more or less elevation of SGPT and ZnT or TT. As soon as hepatic function was impaired slightly, there occurred hepatic dysmicrocirculation. But in the cases of severe ultrastructural hepatic dysmicrocirculation serum gamma globulin elevation values and A/G ratio exchanges were much higher than those in the cases of slight changes. There was some significance on the judgment of sick condition, slight or severe. Values of the elevation of serum gamma globulin and A/G ratio exchanges were much more obvious than SGPT, ZnT and TT changes. These findings suggest that the extents of pathological changes and dysfunction of the liver in chronic viral hepatitis B are correlated to the extent of hepatic microcirculation impairment. So in the treatment of chronic hepatitis early administration of medicine to improve the liver microcirculation should be considered.

Adolescent↗