Activation of phospholipase D involved in both injury and survival in A549 alveolar epithelial cells exposed to H2O2.

To determine the role of the phospholipase D (PLD) pathway in injury and survival of alveolar epithelial cells, A549 cells were exposed to H(2)O(2) (500 microM) which resulted in time-dependent injury and bi-phasic increase of PLD activity at 5 min and at 3 h, respectively. n-Butanol (0.5%) inhibited PLD activation, attenuated cell injury at 5 min of H(2)O(2) exposure, but enhanced injury at 3h of exposure. This activation was inhibited by treatment with catalase (500 units/ml). Exogenous phosphatidic acid mimicked the effects of PLD activation, and diphenyliodonium (NADPH oxidase inhibitor) reversed the decline in cell viability induced by H(2)O(2) exposure. Propranolol (phosphatidic acid phospholydrolase inhibitor) and quinacrine (phospholipase A2 inhibitor) had weak effects on H(2)O(2)-induced PLD activation but reversed H(2)O(2)-induced injury. We speculate that PLD activation at the initiation of H(2)O(2) exposure predominantly results in NAPDH oxidase activation, which mediates A549 cell injury, but turns to mediating cell survival as the H(2)O(2) attack continues, which might be mainly due to the accumulation of intracellular phosphatidic acid.

[Diagnosis and surgical treatment of giant intrathoracic solid tumors].

OBJECTIVE: To summarize the experience in diagnosis and surgical treatment of giant intrathoracic solid tumors. METHODS: The data of surgically treated 36 patients with giant intrathoracic solid tumors were analyzed, including 19 males and 17 females. Complete resection was achieved in 34 cases with superior vena cava angioplasty in 3 cases and ligation of the left anonymous vein in 2 cases. Six patients received postoperative radiotherapy. RESULTS: The symptoms in 32 cases were significantly improved. Two patients (5.6%) died of postoperative respiratory infection and failure. The mean postoperative hospital stay was 14.2 days. Pulmonary edema occurred in 6 cases due to rapid decompression of the lung. Pathological results showed that 25 cases had benign tumors and 11 had malignancy. During the follow-up of 1 to 22 years, all patients with benign tumors were still alive, but the patients with malignant tumors had a mean survival time of only 2.1 years. CONCLUSION: Surgical treatment for giant intrathoracic solid tumors is suggested whenever technically possible. Even though a tumor can not be completely resected, satisfied results could still be achieved if combined with postoperative radiotherapy. Proper anesthesia, satisfied exposure with a suitable incision, appropriate resection pattern and hemostatic method are the keys for successful surgical treatment.

Coronary artery bypass grafting after pneumonectomy.

When open-heart operations are necessary in patients who have undergone pneumonectomy, the unavoidable shift of mediastinal structures should be carefully considered. Surgical access, revascularization procedures, and the institution of cardiopulmonary bypass can all require approaches that differ from the usual. In particular, no general recommendations exist regarding the management of patients who undergo coronary artery bypass grafting after pneumonectomy. We successfully performed coronary artery bypass grafting in a 57-year-old man who had undergone a left pneumonectomy 7 years previously. Because the patient's heart was completely displaced into the left posterior hemithorax, access via a left posterolateral thoracotomy was chosen. Saphenous vein grafts were chosen over the internal mammary artery. The distal anastomoses were performed with use of the off-pump technique; for the proximal anastomosis, 2 venous grafts were implanted into the descending aorta. The patient's postoperative course was uneventful, and postoperative angiography revealed patent grafts. Herein, we discuss the case of this patient, and we present some considerations that can influence surgical approaches in similar circumstances.

[Protective effect of protein kinase C on heart function: an experiment with isolated rabbit hearts].

OBJECTIVE: To investigate the protective effect of protein kinase C on heart function. METHODS: The hearts of 40 rabbits were isolated, underwent Langendorff perfusion, and randomly divided into 4 equal groups: Group I (control group, the heart underwent long ischemia or preservation for I hour, was re-warmed and re-infused, and then re-perfused with K-H fluid), Group II (ischemic preconditioning group, perfusion was stopped for 5 minutes before the long ischemia, then the aorta was re-infused), Group III (specific activator of PKC, phorbol myristate acetate was infused inversely via the aorta before the perfusion of K-H fluid), and Group IV (polymyxin B, a specific antagonist of PKC, was infused after the infusion of PKC). Before the preservation and by the end of reperfusion left ventricle end systolic pressure (LVESP), and left ventricle end diastolic pressure (LVDSP) were measured. At the end of experiment specimens of myocardium were collected from each heart to measure the water content, the levels of lactic dehydrogenase and MB isoenzyme of creatine kinase (CK-MB), superoxide dismutase (SOD), and malonyldialdehyde (MDA). TUNEL method was used to measure the number of apoptotic cardiomyocyte. RESULTS: All heart resumed beating. The LVESP of Group II and III were both significantly higher than those of Groups I and IV (all P < 0.05) and the LVESP of Group III was significantly higher than that of Group II too (P < 0.05). The LVEDP of Group II and III were both significantly lower than those of Groups I and IV (all P < 0.05) and the LVEDP of Group III was significantly lower than that of Group II too (P < 0.05). The levels of CK-MB, LDH, and SOD of Group II and III were all significantly higher than those of Groups I and IV (all P < 0.05) and the levels of CK-MB and LDH of Group III was significantly higher than that of Group II too (P < 0.05). The level of MDA of Group II and III were both significantly lower than those of Groups I and IV (all P < 0.05) and the level of MDA of Group III was significantly lower than that of Group II too (P < 0.05). The water contents of Group II and III were both significantly lower than those of Groups I and IV (all P < 0.05). The numbers of TUNEL positive cell and apoptotic cells of Group II and III were all significantly lower than those of Groups I and IV (all P < 0.05). CONCLUSIONS: PKC can be activated by transient ischemia and PMA. PKC protects the heart function effectively.

Influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves in vitro.

OBJECTIVE: To assess the influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves. METHODS: US-made CarboMedics bileaflet valve, China-made Jiuling bileaflet valve and C-L tilting disc valve were tested via a pulsatile flow simulator in the aortic position. Testing conditions were set at mimic cardiac rates of 55 bpm, 75 bpm, 100 bpm with a constant mimic cardiac output of 4 L/min. The mean pressure differences (deltaP), leakage volumes (L(E)V) and closing volumes (C(L)V) across each valve, and effective orifice areas (EOA) were analyzed. RESULTS: Within physiological range, deltaP, L(E)V, and C(L)V decreased as mimic cardiac rate increased, with a large extent of variance. EOA increased along with an increase in mimic cardiac rate. It was a different response in terms of cardiac rate alteration for different types of mechanical prosthetic cardiac valves. CONCLUSION: Mimic cardiac rate change affects hydrodynamics of mechanical prosthetic cardiac valves. Within physiological range, the hydrodynamic of prosthetic bileaflet valve is better than that of tilting disc valve.

[Experimental study of differentiation of mouse bone marrow stromal stem cells into progenitor cardiomyocyte in vitro].

OBJECTIVE: To investigate the possibility of inducing mouse bone marrow stromal stem cells (MSCs) into progenitor cardiomyocytes in vitro. METHODS: The MSCs were isolated by adhesion culture in vitro and flow cytometery was employed to identify the phenotypes of the cell passages. 5-azacytidine was used to induce the stem cells to differentiate into cardiomyotes in the experimental group, which were then detected by RT-PCR, semi-quantitative RT-PCR, Western-blot analysis, electron microscopy and immunofluorescence technique. RESULTS: The isolated subcultured MSCs displayed a fusiform cell-like morphology. The MSCs were uniformly positive for CD29 and CD44 but negative for CD34 and CD45, and after induction, they expressed cardiomyocyte-specific transcription factors (NKx2-5/Csx and GATA4) and fetal ventricular cardiomyocyte-specific gene beta-myosin heavy chain, but not adult ventricular cardiomyocyte-specific gene alpha-myosin heavy chain as detected by RT-PCR. Western blotting identified the expressions of alpha-sarcomeric actin and desmin in the induced MSCs, with myofilament formation observed under electron microscope. Compared with the control group, the expression level of DNA methyltransferase mRNA was significantly lowered in the experimental group as observed by semi-quantitative RT-PCR (P<0.05). CONCLUSION: MSCs are capable of differentiating into progenitor cardiomyocytes.

[Dynamic change of apoptosis of alveolar cells in ischemia-reperfusion induced pulmonary injury: an experimental study with rats].

OBJECTIVE: To observe the dynamic changes of alveolar apoptosis in ischemia-reperfusion (IR) induced pulmonary injury, and to evaluate the roles of these two cell death styles, apoptosis and necrosis, in the progress of lung function deterioration in pulmonary IR injury. METHODS: Fifty-four Sprague-Dawley rats were made ischemia/reperfusion models by ischemia and reperfusion in situ in single lung. Thirty-six of the 54 rats in the experimental group were re-divided into 6 equal subgroups to undergo detection of partial pressure of oxygen (PaO2) of blood in left atrium, detection of lung tissue wet weight/dry weight ratio, histology of lung by light microscope, examination of ultrastructural changes of cells by transmission electron microscopy, and quantitative detection of apoptotic cells in the right middle lobe by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) 0 h, 0.5 h, 1 h, 2 h, 6 h, and 12 h respectively after the reperfusion (subgroups R0, R(0.5), R1, R2, R6, and R12). Another 18 rats in the experimental group were re-divided into 3 subgroups of 6 rats to undergo insertion of venous catheter into the main pulmonary artery via right ventricle to perfuse trypan blue so as to evaluate the cell death degree. The death index was observed under light microscope and the necrosis index was indirectly calculated by the equation: death index = apoptotic index + necrosis index. Thirty-six rats underwent sham operation. Twelve rats were used as preoperative blank controls. RESULTS: Proliferation of alveolar type II, but not alveolar type I cell, accompanied by ultrastructural morphological changes were seen 1 h, 2 h, and 6 h after reperfusion, the most prominently 2 h after reperfusion. Apoptotic index was elevated since 1 h after reperfusion, and peaked 2 h after reperfusion. Statistical analysis indicated that, compared with apoptotic index, the necrotic index was of more prominent correlation with blood oxygen partial pressure and wet/dry weight ratio. CONCLUSION: Alveolar apoptosis occurs in the early stage of reperfusion, and becomes the most prominent 2 h after reperfusion. Most apoptotic cells are alveolar type II cells. In the two styles of cell death in pulmonary IR injury, alveolar necrosis is more prominently correlated with progress of lung function deterioration.

Effects of phospholipase D on cardiopulmonary bypass-induced neutrophil priming.

OBJECTIVE: To investigate the relationship between phospholipase D (PLD) activation and neutrophil priming induced by cardiopulmonary bypass (CPB), and try to clarify whether CPB-induced systemic inflammatory response can be attenuated by inhibiting neutrophilic PLD activation. METHODS: Neutrophils were isolated from arterial blood of 8 patients undergoing valve replacement before operation and 30 min after initiation of CPB respectively. Both the preoperative and CPB-stirred neutrophils were subdivided into 5 groups by receiving different experimental interventions: (1) bacterial lipopolysaccharide (LPS, 10 ng x ml(-1)), (2) N-formylmethionylphenylalanine (fMLP, 1 micromol x L(-1)), (3) LPS+fMLP, (4) 1-butanol (0.5%)+LPS+fMLP, (5) vehicle. Elastase and myeloperoxidase (MPO) release was measured for the parameters of neutrophil activation, neutrophil PLD activity was determined by quantitation of choline produced from the stable product of phosphatidylcholine catalyzed by PLD. RESULTS: (1) Preoperative neutrophils treated with LPS+fMLP presented significantly higher PLD activity (13.48+/-2.61 nmol choline x h(-1) x mg(-1)) and released more elastase and MPO than cells treated with vehicle (PLD activity 3.70+/-0.49 nmol choline x h(-1) x mg(-1)), P<0.01), LPS (P<0.01) and fMLP respectively. In 1-butanol+LPS+fMLP group, PLD activity of preoperative neutrophils was lower than that in LPS+fMLP group (P<0.01), besides the release of elastase and MPO decreased sharply below both LPS+fMLP and fMLP groups (P<0.01). In LPS group, PLD activity was higher (P<0.01), while elastase and MPO release did not differ from control. fMLP group presented PLD activity, elastase and MPO release higher than control (P<0.01); nevertheless, lower than LPS+fMLP group (P<0.01). (2) CPB-stirred neutrophils presented prominent PLD activity increment, and even the control level was 3.59-fold of the pre-operative control (P<0.01). PLD activity in LPS+fMLP group was higher than that in other groups. Notably, PLD activity was even nonstatistically lower in 1-butanol+LPS+fMLP group than that in LPS or fMLP group. CPB-stirred neutrophils in LPS+fMLP group released more elastase and MPO than control, LPS, and 1-butanol+LPS+fMLP groups did (P<0.01); however, neither of the release was statistically different from that of fMLP group. CONCLUSIONS: Cardiopulmonary bypass enables neutrophil priming accompanied with significant increase in PLD activity. Inhibition of neutrophil PLD activation attenuates its priming and may alleviate CPB-induced systemic inflammatory reaction.

[Application of dynamic bubble trap in coronary artery bypass with cardiopulmonary bypass: an initial study].

OBJECTIVE: To investigate the effectiveness of dynamic bubble trap (DBT) on air microbubble elimination from both the cardiopulmonary bypass (CPB) circuit and middle cerebral arteries, and evaluate its possible impact on blood cells and coagulatory function. METHODS: Twenty patients undergoing coronary artery bypass graft (CABG), 12 males and 8 females, with similar perioperative data were assigned randomly to DBT group and control group. Each CABG was finished with identical circuit sets except the integration of a DBT between the arterial filtrator and the aortic cannula in the DBT group. Air microbubbles were detected before and after the integration of DBT with ultrasonographic detector and microembolism signals (MES) in middle cerebral arteries were counted by transcranial Doppler (TCD). Plasma free hemoglobin (PFH), lactate dehydrogenase (LDH), fibrinogen, platelet count, coagulation factor II and anti-thrombin III (ATIII) were also assayed respectively before the operation, at the termination of CPB, and 6 hours after the operation. RESULTS: In the DBT group the microbubbles of different size could be expelled significantly with the clearance rates between 68% - 74% (10 - 120 microm bubbles), 79% - 81% (20 - 120 microm bubbles), and 88% - 96% (40 - 120 microm bubbles). During the total CPB phase, the mean number of MES reached 197 +/- 137 in the control group and 158 +/- 178 in the DBT group, without a significant difference between these 2 groups. The PFH and LDH levels raised while the platelet count, fibrinogen level, and coagulation factor II and AT III activities decreased sharply after CPB in these 2 groups, however without significant differences in these parameters between the two groups. CONCLUSION: DBT integration into the CPB circuit enhances neither blood cell damage nor coagulation disturbance. DBT effectively eliminates air microbubbles in arterial conduit; however, its microembolus elimination function is prone to die down during the total period of CPB.