The impacts of competitive flow on hemodynamic performance of graft after coronary artery bypass surgery / 医用生物力学

Objective To investigate the influence of competitive flow at different lelves on wall shear stress (WSS) of left internal mammary artery graft after coronary artery bypass grafting. Methods The left internal mammary artery (LIMA) left anterior descending (LAD) anastomotic model was extracted and reconstructed from CT images based on thresholding method by using SimVascular software. The competitive flow was divided into three groups according to different stenosis of LAD, including no competitive flow group (100% stenosis of LAD), mild competitive flow group (50% and 75% stenosis of LAD) and severe competitive flow group (0% and 30% stenosis of LAD). The hemodynamic performace of the anastomotic model under different conditions of competitive flow was observed by computational fluid dynamics (CFD) method. Results With the increment of competitive flow, the value of WSS was decreased gradually while the oscillation of WSS was increased remarkably in LIMA graft. The time average WSS (TAWSS) of LIMA graft in severe competitive flow group (0% stenosis: 2.73 Pa, 30% stenosis: 2.85 Pa) was lower than that in the mild competitive flow group (50% stenosis: 4.77 Pa, 75% stenosis: 6.01 Pa) and no competitive flow group (100% stenosis: 8.64 Pa), while its oscillatory shear index (OSI) (0% stenosis: 0.206; 30% stenosis: 0.085) was much higher than that in other two groups (50% stenosis: 0.014; 75% stenosis: 0.013; 100% stenosis: 0.006). Conclusions When the stonosis of LAD was smaller than 50%, the WSS in LIMA graft was obviously lower and oscillatory due to severe competitive flow. Such unfavorable feature of WSS may influence the long term-patency of LIMA graft and long term-survival of operations.

Loss of p120 catenin aggravates alveolar edema of ventilation induced lung injury / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>p120 catenin (p120ctn) is an adheren junction protein that regulates barrier function, but its role has not been explored in alveolar edema induced by ventilation. We measured stretch-induced cell gap formation in MLE 12 cells due to the loss of p120. We hypothesized that alveolar permeability was increased by high lung inflation associated with alveolar epithelia cell tight junctions being destroyed, which resulted from the loss of p120.</p><p><b>METHODS</b>Cultured MLE12 cells were subjected to being stretched or un-stretched (control) and some cells were pretreated with pp2 (c-src inhibitor). After the end of stretching for 0, 1, 2, and 4 hours, the cells were lysed, and p120 expression and c-src activation was determined by Western blotting analysis. In vivo, SD rats were taken to different tidal volumes (Vt 7 ml/kg or 40 ml/kg, PEEP = 0, respiratory rate 30-40 betas/min) for 0, 1, 2, and 4 hour and some were pretreated with pp2, and alveolar edema was calculated.</p><p><b>RESULTS</b>It was found that p120 expression was reduced and c-src activation increased in a time-dependent and strain-dependent manner due to cyclic-stretch of the alveolar epithelial cells. These changes could be reversed by inhibition of c-src. We obtained similar changes in rats when they were subjected to large tidal volumes and the alveolar edema increased more than in rats in the low Vt group. Pretreated the rats with inhibition of c-src had less pulmonary edema induced by the high tidal volume ventilation.</p><p><b>CONCLUSIONS</b>Cyclic stretch MLE 12 cells induced the loss of p120 and may be the same reason by high tidal volume ventilation in rats can aggravate alveolar edema. Maintenance of p120 expression may be a novel therapeutic strategy for the prevention and treatment of ventilation induced lung injury (VILI).</p>

Relationship between the quantities of peripheral dendritic cells and of serum HBV DNA and the inflammatory reaction levels in the liver / 中华肝脏病杂志

<p><b>OBJECTIVES</b>To investigate the relationship between the quantity of peripheral dendritic cell (DC) and of serum HBV DNA and the inflammatory level in chronic hepatitis B (CHB).</p><p><b>METHODS</b>The myeloid DC (DC1) and plasmacytoid DC (DC2) in fresh peripheral blood were enumerated by using three-color flow cytometry in chronic hepatitis B patients and healthy donors. The hepatic inflammatory levels were evaluated by percutaneous liver biopsy. The serum HBV DNA levels were determined by real-time PCR.</p><p><b>RESULTS</b>CHB patients with serum HBV DNA < or = 10(6) copies/ml exhibited a significant increase in the percentage of circulating DC2 in comparison with those of CHB patients with serum HBV DNA > or = 10(6) and with healthy donors (P < 0.05). The two latter groups showed no significant differences between each other. There was also no significant difference in the relative quantity of peripheral blood DC1 among the three groups mentioned above (P = 0.162). No evidence was found to support that the relative quantity of peripheral blood DC2 was associated with the clinical severity of the disease or the inflammatory level in the liver (P > 0.05).</p><p><b>CONCLUSION</b>The relative quantity of peripheral blood DC2 is associated with HBV DNA level. It is suggested that DC2 may play a pivotal role in inhibiting HBV replication in CHB patients. There was no relationship found between relative quantities of DCs and the inflammatory level in the liver.</p>