Heat shock protein 72 normothermic ischemia,and the impact of congested portal blood reperfusion on rat liver

INTRODUCTIONFrom the technical aspect of liver surgery ,control of bleeding during hepatic parenchymal resection is one of the most important procedures in hepatectomy .Pringle,s maneuver ,a temporary cross-clamping of the hepatoduodnal ligament ,has often been used for this purpose[1],This is the simplest and userul technique to reduce intraoperative blood loss .

Catalytic reaction mechanism of L-lactate dehydrogenase: an ab initio study

Studies on the catalytic reaction mechanism of L-lactate dehydrogenase have been carried out by using quantum chemical ab initio calculation at HF/6-31G* level. It is found that the interconversion reaction of pyruvate to L-lactate is dominated by the hydride ion Hr transfer, and the transfers of the hydride ionH r and protonH r are a quasi-coupled process, in which the energy barrier of the transition state is about 168.37 kJ/mol. It is shown that the reactant complex is 87.61 kJ/mol lower, in energy, than the product complex. The most striking features in our calculated results are that pyridine ring of the model cofactor is a quasi-boat-like configuration in the transited state, which differs from a planar conformation in some previous semiempirical quantum chemical studies. On the other hand, the similarity in the structure and charge between theH r transfer process and the hydrogen bonding with lower barrier indicates that the Hr transfer process occurs by means of an unusual manner. In addition, in the transition state the electrostatic interaction between the substrate and the active site of LDH is quite strong and the polarization of the carbonyl in the substrate is gradually enhanced accompanying the formation of the transition state. These calculated results are well in accord with the previous experimental studies, and indicate that the charge on the hydride ion Hr is only +0.13e in the transition state, which is in agreement with the reported semiempirical quantum chemical calculations.

Modified catalytic performance of Lactobacillus fermentum l-lactate dehydrogenase by rational design

l-Lactate dehydrogenases can reduce alpha-keto carboxylic acids asymmetrically and generally have a broad substrate spectrum.l-Lactate dehydrogenase gene(LF-l-LDH0845)with reducing activity towards 3,4-dihydroxyphenylpyruvate and phenylpyruvate was obtained from Lactobacillus fermentum JN248.To change the substrate specificity of LDH0845 and improve its catalytic activity towards large substrates,site-directed mutation of Tyr221 was performed by analyzing the amino acids in the active center.Kinetic parameters show that the kcat values of Y221F mutant on 3,4-dihydroxyphenylpyruvate,4-methyl-2-oxopentanoate,and glyoxylate are 1.21 s^(−1),1.35 s^(−1),and 0.72 s^(−1),respectively,which are 420%,150%and 130%of the wild-type LDH0845.This study shows that the mutations of Y221 can significantly change the substrate specificity of LDH0845,making it become a potential tool enzyme for the reduction of alpha-keto carboxylic acids with large functional groups.

利用受体配体亲和超滤技术筛选中药天麻中乳酸脱氢酶抑制剂

以乳酸脱氢酶作为靶蛋白,利用受体配体亲和超滤技术筛选中药天麻提取物中乳酸脱氢酶受体,进而筛选抗缺血性脑卒中活性成分。利用液质联用技术确定了天麻提取物中16个化学成分,利用受体配体亲和超滤技术确定(S)-(4-羟苄基)-谷胱甘肽-葡萄糖苷、柠檬酸、天麻素A、巴利森苷E、巴利森苷G、腺嘌呤葡萄糖苷、巴利森苷Q、巴利森苷V为天麻提取物中乳酸脱氢酶抑制剂。

血清CRP、PCT、LDH、cysC水平与蜂螫伤后肾损伤的关系

【目的】探讨血清C反应蛋白(CRP)、降钙素原(PCT)、乳酸脱氢酶(LDH)、胱抑素C(cysC)水平与蜂螫伤后肾损伤的关系。【方法】回顾性分析130例蜂螫伤患者的临床资料,依据患者是否发生急性肾损伤(AKI)分为AKI组(n=38)与非AKI组(n=92)。在入院时收集两组患者的基线资料信息并行实验室指标[血小板计数(PLT)、CRP、PCT、LDH、cysC]检测。比较两组相关指标的差异,通过受试者工作特征曲线(ROC曲线)分析血清CRP、PCT、LDH、cysC预测蜂螫伤患者并发AKI的价值,并将两组有差异的信息纳入多因素Logistic回归分析,行量化赋值,明确蜂螫伤患者并发AKI的影响因素。【结果】两组性别、年龄、蜂螫伤部位、合并疾病、蜂螫伤时间及PLT水平相比较,差异无统计学意义(P>0.05)。AKI组胡蜂螫伤、伤后入院时间≥6h占比显著高于非AKI组,血清CRP、PCT、LDH、cysC水平显著高于非AKI组,且差异均有统计学意义(P<0.05)。经ROC曲线分析显示,CRP≥6.285mg/L、PCT≥1.570ng/mL、LDH≥1482.175U/L、cysC≥1.430mg/L能够用于预测蜂螫伤患者并发AKI(P<0.05)。经多因素Logistic回归分析证实螫伤蜂种、伤后入院时间及血清CRP、PCT、LDH、cysC水平是蜂螫伤患者并发AKI的显著影响因素(P<0.05)。【结论】血清CRP、PCT、LDH及cysC水平是蜂螫伤患者并发AKI的显著影响因素,且CRP≥6.285mg/L、PCT≥1.570ng/mL、LDH≥1482.175U/L、cysC≥1.430mg/L可预测AKI的发生。

Protective effect of estradiol on hepatocytic oxidative damage

AIM: To examine the protective effect of estradiol on the cultured hepatocytes under oxidative stress. METHODS: Hepatocytes of rat were isolated by using perfusion method, and oxidative stress was induced by a serum-free medium and FeNTA. MDA level was determined with TBA method. Cell damage was assessed by LDH assay. Apoptosis of hepatocytes was assessed with cytoflowmetric analysis. Expression of Bcl-xl in cultured hepatocytes was detected by Western blot. The radical-scavenging activity of estradiol was valued by its ability to scavenge the stable free radical of DDPH. RESULTS: Oxidative stress increased LDH from 168 +/- 25 x 10(-6)IU.cell(-1) to 780 +/- 62 x 10(-6)IU.cell(-1) and MDA(from 0.28 +/- 0.07 x 10(-6)nmol.cell(-1) to 1.35 +/- 0.12 x 10(-6)nmol.cell(-1)) levels in cultured hepatocyte, and estradiol inhibited both LDH and MDA production in a dose dependent manner. In the presence of estradiol 10(-6)mol.L(-1), 10( -7 )mol.L(-1) and 10(-8)mol.L(-1),the LDH levels are 410 +/- 53 x 10(-6)IU.cell(-1) (P【0.01 vs oxidative group), 530 +/- 37 X 10(-6)IU.cell(-1 ) (P【0.01 vs oxidative group), 687+/-42 x 10(-6)IU.cell(-1) (P【0.05 vs oxidative group) respectively, and the MDA level are 0.71+/-0.12 x 10(-6)nmol.cell(-1) (P【0.01 vs oxidative group),0.97+/-0.11 x 10(-6)nmol.cell(-1 )(P【0.01 vs oxidative group) and 1.27+/-0.19 x 10(-6)nmol.cell(-1) respectively. Estradiol suppressed apoptosis of hepatocytes induced by oxidative stress, administration of estradiol(10(-6)mol/L)decreased the apoptotic rate of hepatocytes under oxidative stress from 18.6 +/- 1.2% to 6.5 +/-2.5%, P【0.01. Bcl-xl expression was related to the degree of liver cell damage due to oxidative stress, and estradiol showed a protective action. CONCLUSION: Estradiol protects hepatocytes from oxidative damage by means of its antioxidant activity.

Alanyl-glutamine dipeptide inhibits hepatic ischemiareperfusion injury in rats

AIM： To investigate the protective effect and mechanism of alanyl-glutamine dipeptide （Ala-GIn） against hepatic ischemia-reperfusion injury in rats. METHODS： Rats were divided into group C as normal control Group （/7=16） and group G as alanyl-glutamine pretreatment 07=16）. Rats were intravenously infused with 0.9% saline solution in group C and Ala-GIn -enriched （2% glutamine） 0.9% saline solution in group G via central venous catheter for three days. Then all rats underwent hepatic warm ischemia for 30 min followed by different periods of reperfusion. Changes in biochemical parameters, the content of glutathione （GSH） and the activity of superoxide dismutase （SOD） in liver tissue, Bcl-2 and Bax protein expression and morphological changes of liver tissue were compared between both groups. RESULTS： One hour after reperfusion, the levels of liver enzymes in group G were significantly lower than those in group C （P〈0.05）. Twenty-four hours after reperfusion, the levels of liver enzymes in both groups were markedly recovered and the levels of liver enzyme in group G were also significantly lower than those in group C （P〈0.01）. One and 24 h after reperfusion, GSH content in group G was significantly higher than that in group C （P 〈0.05）. There was no statistical difference in activities of SOD between the two groups. One and 24 h after reperfusion, the positive expression rate of Bcl-2 protein was higher in group G than in group C （P〈0.05） and the positive expression rate of Bax protein was lower in group G than in group C （P〈0.05）. Histological and ultrastructural changes of liver tissue were inhibited in group C compared to group G. CONCLUSION： Our results suggest that Ala-GIn pretreatment provides the rat liver with significant tolerance to warm ischemia-reperfusion injury, which may be mediated partially by enhancing GSH content and regulating the expression of Bcl-2 and Bax proteins in the liver tissue.

Protective effect of exogenous adenosine triphosphate on hypothermically preserved rat liver

AIM:To clarify the protective effect of exogenous adenosine triphosphate(ATP)on hypothermically preserved rat livers. METHODS:Establishment of continuous hypothermic machine perfusion model,detection of nucleotides in hepatocytes with HPLC,measurement of activities of LDH and AST in the perfusate,observation of histopathological changes in different experiment groups,and autoradiography were carried out to reveal the underlying mechanism of the protective effect of ATP. RESULTS:The intracellular levels of ATP and EC decreased rapidly after hypothermic preservation in control group,while a higher ATP and EC level,and a slower decreasing rate were observed when ATP-MgCl_2 was added to the perfusate (P<0.01).As compared with the control group,the activities of LDH and AST in the ATP-MgCl_2 group were lower(P<0.05). Furthermore,more severe hepatocyte damage and neutrophil infiltration were observed in the control group.Radioactive [α-^(32)P]ATP entered the hypothermically preserved rat hepatocytes. CONCLUSION:Exogenous ATP has a protective effect on rat livers during hypothermical preservation.However,Mg^(2+) is indispensable,addition of ATP alone produces no protective effect.The underlying mechanism may be that exogenous ATP enters the hypothermically preserved rat liver cells.

Effect of adrenalectomy on rat epididymidis

AIM: To investigate the effect of adrenalectomy (ADX) on the epididymidis of Sprague-Dawley rats. METHODS: The histological, biochemical (cholesterol protein, zinc, copper, alkaline and acid phosphatase aryl sulphatase, lactic dehydrogenase and leucine amino peptidase) and hormonal (FSH, LH and testosterone) changes of caput and cauda epididymis in ADX rats were observed. RESULTS: Organ wet weight, histological studies and morphometric measurements indicated a cellular degeneration in caput and cauda epididymis of ADX rats. Serum testosterone level was significantly lower in ADX than in sham-operated rats, while the serum FSH and LH were below the detection limit of 1 mIU/mL. The enzymatic activity was higher in ADX than in sham-operated rats. Epididymal zinc level increased whereas copper level decreased in ADX rats compared to the sham-operated. CONCLUSION: Adrenalectomy leads to degeneration of caput and cauda epididymidis epithelial cells as a result of decreased supply of testosterone.

Zinc is a potent heat shock protein inducer during liver cold preservation in rats

OBJECTIVE: A simple liver cold preservation model was established to study the synthesis of heat shock protein 70 (HSP70) induced by zinc (ZnSO(4), i.p.) and its protection during liver cold preservation in rat. METHODS: Male Wistar rats were divided into 5 groups (n = 6). In control group rat received no pretreatment; in Zn-1 group, Zn-2 group, and Zn-3 group rats were pretreated with zinc sulfate at a dose of 5 mg/kg, 10 mg/kg, 15 mg/kg respectively; and in H group rat received heat shock preconditioning (42.5 degrees C x 15 min). Livers were preserved in UW solution for 6, 12 and 24 h, respectively. HSP70 was analyzed by Western blot. Aspartate transaminase (AST) and lactate dehydrogenase (LDH) values of the perfusion solution and the histology of the liver were evaluated. RESULTS: HSP70 expression was markedly elevated after pretreatment with zinc and heat shock. AST and LDH values in the Zn-1, Zn-2 and H groups were significantly lower than those in the control group, respectively (P 0.05), whereas the AST and LDH values in the Zn-3 group were much higher than those in the control group. Histology results showed that liver injury in the Zn-1, Zn-2 and H groups were minimal, while it was severe in the Zn-3 group. CONCLUSIONS: Zn(2+) is a potent and feasible inducer of HSP expression and is able to protect liver from cold preservation injury. The proper inducing dosage of Zn(2+) ranged from 5 mg/kg to 10 mg/kg. The dosage of 15 mg/kg for Zn(2+) as a HSP inducer is not indicated for its severe toxicity to the liver.

精神分裂症分子遗传学研究

用限制性内切酶(SacI)和 G_6PD 基因探针分析了50例精神分裂症患者(男女各半)和50例正常者(男妇各半)的基因组 DNA 中的 G_6PD 基因的 RFLP。研究结果提示,X 染色体长臂可能存在精神分裂症的易患性基因。

Electroacupuncture preconditioning alleviates myocardial ischemia-reperfusion injury through the hypothalamic paraventricular nucleus-interposed nucleus nerve pathway

OBJECTIVE:To explore whether the paraventricular nucleus(PVN)participates in regulation of the antimyocardial ischemia-reperfusion injury(MIRI)effect of electroacupuncture(EA)and whether this is achieved through the PVN-interposed nucleus(IN)neural pathway.METHODS:The modeling method of myocardial ischemia reperfusion injury was achieved by ligating the left anterior descending coronary artery in SpragueDawley rats.We used the Powerlab multi-channel physiological recorder system to record electrocardiograms and analyze the changes in ST segment displacement;2,3,5-Triphenyltetrazolium chloride staining was used to observe the percentage of myocardial infarction areas.Detecting cardiac troponin I(cTnI),lactate dehydrogenase(LDH)in serum was done with an enzyme-linked immunosorbent assay kit.Morphological changes in the myocardium were detected in each group with hematoxylin-eosin staining of paraffin sections.Detection of c-fos protein expression in the PVN of the hypothalamus was done with the immuneofluorescence method.The Plexon multi-channel acquisition system recorded PVN neuron discharges and local field potentials in each group of rats.Offline Sorter software was used for cluster analysis.Neuro Explorer software was used to perform autocorrelation,raster and frequency characteristics and spectral energy analysis of neuron signals in each group.RESULTS:Compared with the MIRI model group,the areas of myocardial infarction in the EA group were significantly reduced;the expression of cTnI,LDH in serum was decreased significantly.The firing frequency of pyramidal cells in the PVN was significantly increased and the spectrum energy map showed energy was reduced,c-fos expression in PVN was reduced,this indicated that neuronal activity in the PVN participates in the effect of EA improving myocardial injury.In addition,we used the kainic acid method to lesion the IN and observed that the effect of EA was weakened.For example,the area of myocardial infarction of lesion IN+EA group in rats was significantly increased compared with that resulting from EA group,the expression of cTnI,LDH in serum was significantly increased,the firing frequency of pyramidal cells in the PVN was significantly reduced.A spectral energy diagram shows that the energy after damage was higher than that of EA group.At the same time,the expression of c-fos in the PVN increased again.CONCLUSION:Our results indicated that the PVN-IN nerve pathway may participate as an effective pathway of EA to improve the effect of myocardial injury.