Effects of seasonal grazing on plant and soil microbial diversity of typical temperate grassland.

Biodiversity is the decisive factor of grassland ecological function and process. As the most important human use of grassland, grazing inevitably affects the grassland biodiversity. However, comprehensive studies of seasonal grazing on plant and soil bacterial, archaeal and fungal diversity of typical temperate grassland are still lacking. We examined the impact of seasonal grazing, including no-grazing (NG), continuous grazing (CG), grazing in May and July (G57), grazing in June and August (G68), and grazing in July and September (G79) on grassland plant and soil microbial diversity based on a long-term field grazing experiment. The results showed that the aboveground plant biomass (AGB) of the seasonal grazing plots was significantly higher than that of the CG plots. Compared with NG, CG increased significantly the Margalef richness index of plant community, while did not significantly change the Shannon, Simpson and Pielou evenness of plant community. Grazing changed the composition and biomass of dominant vegetation. Long-term grazing decreased the proportion of Leymus chinensis (Trin.) Tzvel. and increased the proportion of Cleistogenes squarrosa (Trin.) Keng. There was no significant change in the Shannoneven, Shannon and Coverage indices of soil bacteria, archaea and fungi between NG and the grazing plots. But the Chao index of soil fungi in G57, G68 and G79 and archaea in G57, G79 was significantly higher than that in CG. The results of correlation analysis showed that the plant diversity in the CG plots was significantly negatively correlated with the soil bacterial diversity. The plant richness in the G57 and G68 plots was significantly positively correlated with the soil archaea richness. Our study showed that seasonal grazing was a sustainable grazing management strategy for maintaining typical grassland plant and soil microbial diversity in northern of China.

Left atrial endocardial dysfunction and platelet activation in patients with atrial fibrillation and mitral stenosis.

OBJECTIVE: This study demonstrated left atrial endocardial dysfunction and platelet activation in patients with atrial fibrillation and mitral stenosis. METHODS: Study included 80 patients with mitral stenosis and atrial fibrillation (40 each with and without left atrial thrombosis), 15 healthy volunteers, and 10 left atrial appendage (LAA) specimens from donor hearts. Blood samples were collected through peripheral vein and left atrium, with peripheral blood samples of volunteers as controls. LAA specimens were collected during operations. LAA expressions of von Willebrand factor (vWF) and P-selectin were determined immunohistochemically; plasma concentrations were measured by enzyme-linked immunosorbent assay. LAA expressions of vWF and P-selectin genes in were quantitated with real-time fluorescent quantitative polymerase chain reaction. RESULTS: The difference in vWF and P-selectin plasma levels between left atrial and peripheral venous blood was not significant; however, peripheral plasma levels of vWF and P-selectin were significantly higher in those with thrombosis than without thrombosis, which in turn were higher than in healthy subjects. Both vWF and P-selectin proteins were stained in both left atrial endocardium and cardiomyocytes. The normalized vWF gene expression relative to control was 3.04 in patients with thrombosis and 2.16 in those without thrombosis (P<.01). The difference in P-selectin gene expressions among the groups was not significant. CONCLUSIONS: No differences were observed in plasma levels of vWF and P-selectin between left atrial and peripheral venous blood. Over expression of vWF gene in LAA may contribute to increased plasma vWF levels. P-selectin and vWF together may play a role in thrombosis.

Off-pump coronary artery bypass grafting with device closure of atrial septal defect.

Patients with coronary artery disease and atrial septal defect may have unique clinical characters. We describe an off-pump combined approach for intraoperative device closure of atrial septal defect during coronary artery bypass grafting.

Coronary artery bypass grafting in adults with congenital heart disease.

BACKGROUND: Adults with congenital heart disease (CHD) and coronary artery disease (CAD) have unique clinical manifestation due to the coexistence of intracardiac anomalies and CAD. Case reports are rare in surgical management of CHD combined with CAD. Our goal is to study the outcome of surgical intervention of CHD and CAD concomitantly. METHODS: From February 2002 to August 2009, 29 adult patients underwent coronary artery bypass grafting (CABG) and surgical correction of CHD concomitantly. Congenital cardiac anomalies include atrial septal defect (ASD) in 21 cases, ventricular septal defect in four cases, atrioventricular septal defect in three cases, and cor triatriatum in one case. Coronary angiography demonstrated: one-vessel disease in 10 cases, two-vessel disease in 11 cases, and three-vessel disease in eight cases. Coronary revascularization and intracardiac anomalies were corrected with cardiopulmonary bypass in 23 cases. There were six patients who had off-pump coronary artery pass grafting (OPCAB) and intraoperative device closure of ASD. RESULTS: One patient died of pulmonary infection and multiorgan failure. Follow-up time was from 2 to 89 months (mean, 42 ± 25 months). One patient with recurrent angina did not need intervention of the revascularization. Six patients who acquired OPCAB and intraoperative device closure of ASD had no complications after surgery. CONCLUSIONS: Surgery for adult patients who had CHD with CAD was a safe and effective management. OPCAB with intraoperative device closure of ASD was a reasonable approach for some selective patients.

Severe calcified saccular pulmonary artery aneurysm.

Pulmonary artery aneurysm is a very rare entity. Severe calcified saccular pulmonary artery aneurysm is not reported in the literature. A 19-year-old man with a severe calcified saccular pulmonary artery aneurysm is described.

[Coronary artery bypass graft for patients with ascending aorta atherosclerosis].

OBJECTIVE: The increasing number of aged patients with severe ascending aorta atherosclerosis who are undergoing coronary artery bypass graft (CABG) present high risk for ascending aortic cannulation, cross-clamping or partial occluding and proximal anastomosis. We reviewed the surgical experience in 22 patients of CABG with ascending aorta atherosclerosis and tried to find the way to minimize the complications. METHODS: Twenty-two patients with severe atherosclerotic and calcified ascending aorta underwent CABG in our hospital. Thirteen of them received CABG on beating heart. Nine patients had their CABG with extracorporeal circulation. With deep hypothermia, we reduced the flow rate and intermittently arrested the circulation for the proximal anastomosis on ascending aorta in 5 patients with neither cross-clamping nor partial occluding. The sequential grafts and "Y" type anastomosis between reversed saphenous venous grafts were employed. RESULTS: Twenty of the patients survived after surgery. One died of inhalation pneumonia in two weeks after surgery. Another died of right hemothorax in ten days after surgery. The complications include: pneumonia 4 patients (18%), angina 2 patients (9%), ventricular fibrillation 1 patients (5%), post-CABG myocardium infarction 1 case (5%) and hemothorax 1 case (5%). There is no neurologic complications or aortic dissection after CABG. CONCLUSION: CABG on beating heart with pedicel arterial grafts is the best approach to performing the surgery without touching the diseased ascending aorta. Ventricular fibrillation under mild hypothermia cardiopulmonary bypass and left ventricular suction were employed for quiet and bloodless field while distal anastomosis had no cross-clamping the ascending aorta. Also deep hypothermia and intermittently circulatory arrest offer quiet and bloodless field for the proximal anastomosis on ascending aorta without cross-clamping or partial-occluding. Distal sequential anastomosis and proximal "Y" type anastomosis are the effective approach to minimizing the proximal anastomosis on the ascending aorta.