重金属铬对小麦根系DNA甲基化水平的影响

采用紫外分光光度法和高效液相色谱法对不同浓度Cr6+对小麦幼苗根系的DNA含量和DNA胞嘧啶甲基化进行了研究。结果表明:(1)Cr6+导致小麦幼苗根系DNA含量显著降低,3 d龄幼苗根系DNA含量下降的幅度大于10 d龄幼苗。(2)5～80mg.L-1和5～100mg.L-1Cr6+依次引发了3 d和10 d龄小麦幼苗根系DNA胞嘧啶甲基化水平的提高,而100mg.L-1Cr6+则导致了3d龄幼苗根系DNA胞嘧啶甲基化水平的降低。说明Cr6+可通过影响小麦幼苗根系DNA甲基化的水平,进而影响小麦的正常生长发育。     

Effects of emodin on activity of sphingomylinase and content of ceramide in rabbit aorta of experimental atherosclerosis

AIM: To study the changes of the sphingomylinase activity and ceramide content in rabbit aorta of experimental atherosclerosis and investigate the effects of emodin on them. METHODS: The qualified rabbits were fed with food containing 1% cholesterol and 5% lard for 10 weeks to establish the animal models. The concentration of cholesterol (TC) was assayed by a enzyme method. Trace-fast-test method was used to test the activity of superoxide dismutase (SOD) and motified- BAMuGuoFu methods was employed to assay the content of myocardial malondialdehyde (MDA). Radiolabeled -enzyme-tracing was used to detect the activity of the sphingomyelinase,and thin-layered scanning was conducted to analyze the content of the ceramide in aorta. RESULTS: The ceramide content in aorta and the sphingomyelinase activity were markedly increased in the rabbits with experimental atherosclerosis. The increase was positively correlated with the content of TC and MDA and negatively correlated with the activity of SOD in blood. Compared to the model animals, emodin at concentration of 5 mg·kg^-1, 10 mg·kg^-1 and 20 mg·kg^-1 respectively reduced the area of plague on endothelium in rabbit's aortic artery and elevated the activity of SOD (P<0.05). The activity of sphingomylinase and the content of ceramide were decreased at the same time (P<0.05). 10 mg·kg^-1 emodin proved to be more effective than 5 mg·kg^-1 and 20 mg·kg^-1 emodin (P<0.01). CONCLUSIONS: Our data suggest that atherosclerosis is related to ceramide signal transduction initiated by factors such as oxidative stress in hypercholesterolemia. The emodin prevents the development of atherosclerosis probably by interfering with the above pathway.     

Changes of serum levels of TXA2 and PGl2 in cirrhosis patients during liver transplantation

AIM：To study the changes of serum levels of thromboxane A₂ (TXA₂) and prostacyclin (PGI₂) in cirrhosis patients during liver transplantation.METHODS：Samples were obtained from 24 cirrhosis patients in end at five time points during liver transplantation.TXA₂ and PGI₂ level were measured by radioimmunoassay.Arterial and mixed venous blood samples used for blood gas analysis were taken at the same time.Intrapulmonary shunt (Qs/Qt) was calculated according to the standard formula.The hemodynamics parameters including continuous cardiac output index (CI),HR,mean artery blood pressure (MABP),MPAP,CVP,PAWP,SVRI,PVRI were measured during liver transplantation.RESULTS：(1) MABP decreased significantly in the early stage of anhepatic period and neohepatic period.(2) CVP,MPAP and PAWP decreased significantly during anhepatic period.They increased significantly after graft reperfusion and remain the high level.(3) CI declined significantly during anhepatic period and increased at 10 min postreperfusion of new liver.(4) SVRI and PVRI increased during anhepatic period and were higher than baseline level at 15 min after reperfusion.SVRI was lower than baseline level at 30 min after reperfusion.(5) Compared with the baseline level,6-keto-PGF1α and TXB₂ increased significantly.Compared with the level before vascular cross-clamping,6-keto-PGF1α decreased during neohepatic period and it had significant difference in statistics at the end of operation.CONCLUSION：Serum levels of TXA₂ and PGI₂ significantly change during liver transplantation and may affect the system and pulmonary circulation to some extent.     

青海果洛州德昂乡屠宰牦牛大肠杆菌耐药性观察

用美国NCCLS规定的纸片扩散法药敏试验,对30株来自德昂乡3个试验点的屠宰牦牛大肠杆菌进行了耐药性观察。结果：30株大肠菌对环丙沙星、庆大霉素、卡那霉素、新霉素、氯霉素,链霉素的耐药率均为O％,痢特灵的中介率为6．7％,氨苄青霉素的耐药率及中介率均为10％,表明抗微生物药使用较少的牦牛体内大肠杆菌耐药性的产生也较少。     

蔬菜中农药残留的分析检测技术及解决措施

农药残留危及人类健康,影响蔬菜生产和出口贸易.只有通过合理使用农药、加强残留检测和法制管理才能尽快解决农药残留造成的严重问题.概述了目前蔬菜中农药残留的分析检测技术,并针对蔬菜中不同的农药残留类型提出了相应的检测手段和解决措施,并对相关技术的发展和应用进行了评估和展望.     

真胃变位奶牛抗氧化能力研究

为了阐明奶牛发生真胃变位(abomasal displacement,DA)时机体抗氧化能力的变化规律,本试验采用分光光度法对27头真胃左方变位奶牛与13头健康奶牛血浆总超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)、总抗氧化能力(T-AOC)、丙二醛(MDA)含量进行了测定.结果 表明,与健康奶牛相比,...     

Effects of leptin on hypoxia-reoxygenation induced apoptosis in human L02 cells and expression of Fas and FasL

AIM: To observe the effect of leptin (LEP) on hypoxia-reoxygenation induced apoptosis in L02 cells.METHODS: In the experiment, L02 cell injury was induced by hypoxic air (95%N2 and 5% CO2). The cultured L02 cells were divided into hypoxic 12 h group (IR group) alone, normal control group and the hypoxic plus leptin (100 μg/L, 200μg/L, 400 μg/L, 800 μg/L and 1 600 μg/L) treatment groups in vitro. Flow cytometry, terminal dUTP nick-end labeling (TUNEL) assay and fluorescent quantitative PCR were used to measure the changes of apoptosis in L02 cells and expression of Fas/FasL mRNA.RESULTS: (1) The percentage of L02 cells apoptosis and positive TUNEL cells significantly increased in IR group compared to control group (P<0.01). When L02 cells were treated with LEP, the percentage of cell apoptosis and positive TUNEL cells were decreased compared to IR group. (2) Compared to control group, the Fas/FasL mRNA expression significantly increased in IR group (P<0.01). When L02 cells were treated with LEP, the Fas/FasL mRNA expression decreased compared to IR group, the effect of LEP at concentration of 400 μg/L was obviously (P<0.05). CONCLUSION: LEP decreases the apoptosis of hypoxic-reoxygenation L02 cells by down-regulation of Fas/FasL mRNA expression in L02 cells.     

Effects of ketotifen administered after intestinal ischemia reperfusion on the survival rate in rats

AIM: To investigate the effect of antihistaminic, ketotifen, administered for three days after intestinal ischemia reperfusion (I/R), on survival rates in SD rats. METHODS: The intestinal I/R model of SD rats was set up with clamping the superior mesenteric artery for 75 min. 72 SD rats were divided into 3 groups: group S for sham group, group M for model group, group K for ketotifen treatment (model + ketotifen 1mg/kg), each group was divided into 2 sub-group: 3rd d and 7th d (eg: group S3, S7, M3, M7, K3, K7; n=12 per sub-group). Ketotifen was administered via caudal vein 5 min before reperfusion in group K, while normal saline was administered in groups S and M and was kept on administering once a day for 3 days after reperfusion. The survival rates were recorded at 3 d or 7 d after operation. The morphological changes of intestinal mucosal and mast cells were observed under light and electron microscopes in survival rats. The concentration of histamine was also determined in the intestinal samples. RESULTS: The survival rate at 3rd d in group M and K was lower than that in group S (P<0.05 or P<0.01). No significant difference of the 3rd d survival rate between group K and M was observed (P>0.05). The survival rate at 7th d in group M7 was lower than that in group S7 and K7 (P<0.05), no significant difference between group K7 and group S7 was found (P>0.05). Light and electron microscope examinations showed slight damage of intestinal mucosal in group M and K in survival rats, while the result in group S was almost normal. Mast cell degranulation was obvious in group M7, partly in group K while none was found in group S. There was no significant difference in Chiu’s score, the expression of tryptase and the number of IMMC among the groups in the survival rats (P>0.05). The concentration of histamine in the intestine in group K7 was lower than that in group S7 and M7. CONCLUSION: Ketotifen administered after intestinal ischemia reperfusion increases the survival rate in rats. The mucosal mast cell degranulation and release of histamine may be adverse to the prognosis of intestinal ischemia reperfusion injury in rats.     

不同来源脂肪酶抑制剂研究进展

脂肪酶抑制剂通过抑制脂肪酶的活性减少油脂的消化吸收,对肥胖症及其并发症有良好的治疗和预防作用。重点阐述了化学合成、微生物发酵和植物提取3种不同来源的脂肪酶抑制剂的研究现状,并对其后期的研究趋势进行探讨。     

食盐对草鱼血清超氧化物歧化酶和溶菌酶活性的影响

草鱼养殖过程中经常使用食盐药浴,以便在高渗环境下杀死病原体.研究食盐药浴后草鱼代谢酶变化,有助于了解食盐药浴对草鱼机体生理免疫的影响.将草鱼(Ctenpharyngodon idella)分别暴露于食盐浓度为0、2%、3%、4%水体中浸浴10 min,然后置入水簇箱中饲养,分别在药浴后12 h、24 h、36 h取样,测定其血清中超氧化物歧化酶(SOD)和溶菌酶(LSZ)活性变化.结果显示,与对照组相比,血清SOD活性在12 h时,2%组中显著上升(P＜0.05),3%、4%组显著下降(P＜0.05);24 h取样时,2%、3%组中无显著差异(P＞0.05),4%组显著下降(P＜0.05);36 h取样时,各组间均无显著差异(P＞0.05);血清LSZ活性各组间均无显著差异(P＞0.05).食盐能引起草鱼SOD活性变化,而对溶菌酶活性影响不大;表明食盐对草鱼不同代谢酶有不同的反应模式,抗氧化酶SOD对食盐应激有敏感的生理应答.