Study on animal intracorneal implantation model with xenogeneic swine corneal stroma

AIM: To study the immunogenicity and biocompatibility of xenogeneic swine corneal stroma as biological carrier for cornea reconstruction and to reconstruct corneal endothelial tissue with this carrier in vitro. METHODS: (1) The lymphocytes from the peripheral blood of F344 rats were immunologically labeled by anti-rat CD25-FITC and anti-rat CD4/CD8-PE, then determined by flow cytometry (FCM) at 12th， 90th day after intracorneal implantation with fresh and dehydrated swine corneal stroma. (2) The fresh and dehydrated grafts made of swine corneal stroma were implanted intralamellarly in corneas of New Zealand rabbits. Clinical examinations were performed monthly and histological examinations were made at 14th， 30th， 60th， 120th and 240th day. (3) The cat corneal endothelial cells were seeded on the Descemet's membrane of the dehydrated swine corneal stroma, then cultured in the medium with epidermal growth factor and laminin for 7 days. The morphology of reconstructed tissue was tested by microscope. RESULTS: (1) Compared to isograft group and negative control, the expression CD4＋CD25＋， CD8＋CD25＋ and CD4＋/CD8＋ of xenograft rat group implantation with swine corneal stroma did not appear significantly different in statistics (P>0.05). (2) In the total 12 rabbits, all the cornea grafts survived without rejection reaction， corneal haze or corneal neovascularization. The fresh grafts got transparent after 2 months, and the dehydrated grafts got transparent after 6 months. Histological study demonstrated both fresh and dehydrated stroma grafts had fused with rabbits'corneal stroma very well without lymphocytes infiltrating. (3) As shown in histological observations, the reconstructed cat corneal endothelial tissue was similar to the nature tissue. Cultured cat endothelial cells connected tightly to each other and attached to the Descemet's membrane closely. CONCLUSION: Swine corneal stroma has low immunogenicity and satisfying biocompatibility,it is an ideal biological carrier for cornea reconstruction in vitro.     

Effects of beta2-adrenergic blocker on cytosolic Ca2+ in isolated cardiomyocytes of rats with myocardial infarction

AIM: To investigate if beta2-adrenergic receptors result in more Ca2+ load after myocardial infarction (MI), the effects of beta2-adrenergic blocker on cytosolic Ca2+ (［Ca2+］i) were studied. METHODS: Male Wistar rats underwent a ligation of left coronary artery (n=9) or a sham operation (n=3). Cardiomyocytes were dissociated at 2, 4 and 8 weeks after MI and ［Ca2+］i was measured via fura-2 fluorescence. The response of cardiomyocytes to isoproterenol (1 μmol/L) in the presence or absence of atenolol (1 μmol/L), beta2-adrenergic blocker ICI118,551 (0.1 μmol/L) or propranolol (1 μmol/L) was examined. RESULTS: ICI118,551 suppressed the increase in ［Ca2+］i induced by isoproterenol at 4 and 8 weeks after MI (24.5%±5.7% vs 57.8%±13.2%, P<0.01; 12.2%±7.9% vs 44.6%±11.3%, P<0.01), but had no effects in control and 2 weeks post-MI groups. It decreased ［Ca2+］i in control and the three post-MI groups by 14.3%, 7.9%, 57.6% and 72.6%, respectively. Atenolol had suppressive effects only in control and 2 weeks post-MI groups (P<0.05). Propranolol had suppressive effects in control and all three post-MI groups (P<0.01). CONCLUSION: Beta 2-adrenergic blocker ICI118,551 exerts negative effects on ［Ca2+］i after MI, and the effects dramatically increase with the progression of MI.     

Changes of gut mucosa antioxidant system and liver,renal function in rats after intestinal ischemia-reperfusion injury

AIM: To investigate the changes of the gut mucosa antioxidant system and liver, renal functions during rat intestinal ischemia-reperfusion injury. METHODS: 30 male Wistar rats underwent 45 min of intestinal ischemia by clamping the superior mesenteric artery followed by reperfusion. The levels of malondialdehyde (MDA), glutathione (GSH), the activities of antioxidant enzymes in the gut mucosa including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), glutathione S- transferase (GST) activity and serum ALT, AST, BUN, Cr were assayed at 2, 4, 8, 12 and 24 h after reperfusion. RESULTS: The levels of MDA and GSH in the gut mucosa increased and decreased significantly at 2 h of reperfusion, respectively (P<0.05). MDA was still lower than sham at 24 h of reperfusion (P<0.05), while GSH decreased to 40% of sham at 4 h of reperfusion (P<0.01) but returned to the level of control at 12 h. The activities of CAT, SOD and GSH-Px did not show significant changes in rat after intestinal ischemia reperfusion. GST decreased 39% at 2 h of reperfusion compared with the sham group and decreased to 56% of sham at 4 h (P<0.05), but returned to the level of control at 12 h after reperfusion. Serum ALT, AST, BUN and Cr increased significantly at 2 h of reperfusion (P<0.05) and increased 208%, 100%, 103%, 41% compared with control at 4 h of reperfusion (P<0.01). However, at 24 h of reperfusion, they returned to normal. CONCLUSION: Intestinal ischemia/reperfusion diminishes GSH level and GST activity, increases MDA level and causes liver and renal reversible damages.     

斯氏线虫在进境原木害虫检疫处理上的应用前景

本文综述了我国进境原木上截获的主要害虫类群；总结了目前进境原木害虫的检疫处理技术；重点介绍了斯氏线虫Steinernema sp．对钻蛀性害虫的防治研究，探讨了斯氏线虫在进境原木害虫检疫处理上的应用前景，提出了应用斯氏线虫防治进境原木害虫所存在的问题及今后的研究方向。     

Cytocompatibiltiy of degradable calcium metaphosphate with human marrow mesenchymal stem cells

AIM: To screen the cytotoxicity of degradable calcium metaphosphate (dCMP) compared with hydroxyapatite (HA). The proliferation and differentiation abilities of human marrow mesenchymal stem cells (MSC) were used to exhibit the cytotoxicity. METHODS: The cell morphology of MSC was analysed after direct contact with dCMP at different time points by scanning electron microscopy analysis. The degradation products of dCMP and HA were analysed with inductively coupled plasma torch and ion chromatography. The cytotoxic effect of degradation products of dCMP was evaluated by FACS, quantitative assay of ALP and ARS, respectively. RESULTS: dCMP enhanced the proliferation of MSC, but didn't interfere the osteogenic differentiation process of MSC and its mineralization. HA inhibited the proliferation of MSC and the mineralization of osteogenic differentiated MSC, while it did not interfere the osteogenic differentiation process of MSC. CONCLUSION: dCMP had a better cytocompatibility with MSC than HA, which might allow for its use as skeleton scaffolds.     

基于GIS与马尔可夫模型的渭河盆地景观动态变化研究

基于1988年与2003年两期TM影像,综合遥感与GIS技术以及景观生态学理论,深入分析了渭河盆地景观变化的数量和空间特征以及由此所引起的一系列生态环境效应,主要表现在:耕地、园地与城镇建设用地面积显著增加,林地、水体和未利用地面积呈减少趋势,城镇建设用地的增加是以侵占大量农田为代价的,而园地与耕地的增加则主要是通过开荒的方式。景观形状趋于复杂,破碎度降低,异质性下降,景观类型有向单一化或非均衡化方向发展的趋势,表明人类的开发活动增强,这样必然导致景观稳定性下降,因而降低了景观抗干扰的能力。最后采用马尔可夫模型对景观的变化趋势进行了预测。     

粤西地区冬季辣椒病毒病发生与防治

冬季辣椒病毒病主要受辣椒品种、气候条件、椒田环境及栽培管理等因素的影响。尖椒品种较圆 (甜 )椒品种的抗病性强 ,青皮尖椒较黄皮尖椒的抗病性强 ;冬季高温干旱 ,病害发生早而且严重 ,扩展速度快 ;椒田在林区或蔗地旁 ,其病害发生较在平原地的椒田普遍严重。在病毒病发生初期 ,及时防治传毒介体 ,用3.85%病毒毖克等药剂连续防治 2～3次 ,对抑制病毒病的扩展蔓延有较好的效果。     

三唑酮种衣剂对小麦白粉菌侵染和非侵染位点硅等元素含量的影响

 借助扫描电子显微镜-X射线能谱分析方法从超微结构和元素水平观测了三唑酮种衣剂包衣处理和空白对照的小麦幼苗上白粉病菌侵染及非侵染位点硅等元素含量的变化。结果表明,接种后20~36 h内三唑酮种衣剂处理的麦苗侵染位点细胞内元素硅含量由5.204%上升为42.064%,非侵染位点由5.821%上升为12.342%;空白对照中侵染位点元素硅含量由低于检测水平上升为17.388%,非侵染位点接种后36 h时为19.460%。在处理和空白对照的麦苗上侵染和非侵染位点均检测到了含量不等的磷、硫、氯等元素存在。     

禾谷镰刀菌接种小麦幼芽及致病力鉴定的初步研究

 由镰刀菌引起的赤霉病是危害小麦、大麦、燕麦、黑麦等禾谷类作物的一种重要病害,广泛分布于世界温暖潮湿地区。在我国赤霉病发病区,禾谷镰刀菌(Fusarium graminearum Schwabe)是主要致病菌。