基于网络药理学及分子对接技术分析丹参-川芎-葛根抗高血压的分子机制

目的 运用网络药理学及分子对接技术探究丹参-川芎-葛根有效活性成分抗高血压的相关靶点及分子机制。方法 通过检索TCMSP、Uniport数据库,获得丹参-川芎-葛根的主要活性成分和相关靶点。通过Genecards数据库获得高血压相关靶点。运用Venny数据库构建丹参-川芎-葛根和疾病靶点韦恩图,得到交集靶点;并将得到的交集靶点导入STRING数据库得到蛋白质相互作用关系。使用RStudio 1.4.1106软件对交集靶点进行GO功能富集和KEGG信号通路富集分析。并利用Cytoscape 3.6.0软件对“药材-活性成分-靶点”、蛋白质-蛋白质相互作用（PPI）、“活性成分-靶点-通路”网络进行可视化。采用AutoDock Tools 1.5.6软件将关键活性成分和核心靶点进行分子对接,运用PyMOL对对接结果进行可视化。结果 通过筛选共获得68个活性成分,759个高血压相关靶点,62个交集靶点。经KEGG通路富集分析发现,丹参-川芎-葛根通过调节流体剪切应力和动脉粥样硬化、钙信号通路、AGE-RAGE、松弛素、cGMP-PKG等通路起到抗高血压的作用。分子对接结果显示,丹参酮ⅡA、隐丹参酮、β-谷甾醇与NOS3、FOS、VEGFA、AKT1等核心靶点结合能力较好。结论 证实了丹参-川芎-葛根多成分、多靶点、多途径的作用规律。     

基于网络药理学与分子对接技术探讨京尼平苷治疗脑缺血的作用机制

目的 运用网络药理学方法和分子对接方法研究京尼平苷治疗脑缺血潜在作用机制。方法 通过PubChem、PharmMapper、GeneCards、OMIM数据库分别对京尼平苷和疾病的靶点进行预测,借助Venny 2.1.0工具将二者取交集获取共有靶点,通过STRING数据库构建交集靶点的蛋白相互作用（PPI）网络,随后通过Cytoscape 3.7.2软件对核心靶点进行网络拓扑分析;基于核心靶点基因开展基因本体（GO）和京都基因与基因组百科全书（KEGG）基因富集分析。利用AutodockTool软件对所筛选的核心靶点分别与京尼平苷进行分子对接。结果 通过STRING数据库构建交集靶点的PPI网络,获得173个交集靶点,包括酪氨酸蛋白激酶（SRC）、蛋白激酶B1（AKT1）、热休克蛋白90α家族A级成员1（HSP90AA1）、PIK3R1、表皮生长因子受体（EGFR）等。京尼平苷治疗脑缺血可能通过调控磷脂酰肌醇-3-羟激酶（PI3K）–蛋白激酶B（Akt）信号通路、糖尿病并发症中的晚期糖基化终末化产物（AGE）–晚期糖基化终末产物受体（RAGE）信号通路、流体剪切应力与动脉粥样硬化通路、Ras信号通路等多种信号通路发挥治疗脑缺血的作用。结论 预测了京尼平苷治疗脑缺血的潜在作用机制,为后续实验研究提供理论依据和研究方向。     

基于网络药理学和分子对接技术探讨黄芩治疗糖尿病心肌病的作用机制

目的 运用网络药理学方法和分子对接技术探讨黄芩抗糖尿病心肌病的活性成分及潜在的作用机制,为后续开展实验研究提供生物信息学基础。方法 通过TCMSP数据库及Swiss Target Prediction数据搜集黄芩活性成分与靶点;采用GeneCards、OMIM数据库查找糖尿病心肌病相关靶点;利用Venny 2.1.0获取药物和糖尿病心肌病的交集靶点;借助String平台和Cytoscape 3.9.0软件拓扑分析并筛选出核心成分及靶点;利用DAVID数据库进行黄芩治疗糖尿病心肌病靶点基因本体(GO)分析和基因组百科全书(KEGG)通路富集分析;采用AutoDock 1.5.7和PyMOL 2.4.1软件进行分子对接及可视化作图。结果 共筛选出36个黄芩活性成分,与糖尿病心肌病的151个交集靶点。GO富集分析得到775条生物过程,167条分子功能,86条细胞组分;KEGG通路分析得到169条,其中晚期糖基化终末产物及其受体(AGE-RAGE)、磷脂酰肌醇-3-激酶(PI3K)-蛋白激酶B(Akt)、丝裂原活化蛋白激酶(MAPK)、肿瘤坏死因子(TNF)、低氧诱导因子-1(HIF-1)是较关键的通路。分子对接结果显示,汉黄芩素、黄芩素、表小檗碱、黄芩新素等与Akt1、TNF、甘油醛-3-磷酸脱氢酶(GAPDH)、白细胞介素-6(IL-6)蛋白等有较强的相互作用,其中与黄芩素结合性最好。结论 黄芩对糖尿病心肌病的治疗作用可能是汉黄芩素、黄芩素、表小檗碱、黄芩新素等活性成分通过调控Akt1、TNF、GAPDH、IL-6等靶点,作用于AGE-RAGE、PI3K-Akt、MAPK等信号通路来实现的。     

基于网络药理学和分子对接技术探讨黄芪甲苷抗抑郁的作用机制

目的 采用网络药理学和分子对接技术研究黄芪甲苷抗抑郁的潜在作用机制。方法 通过GEO、DrugBank、TTD、DisGeNet、GeneCards数据库获得抑郁症疾病靶点,检索PharmMapper和SwissTargetPrediction数据库获得黄芪甲苷的预测靶点。使用R软件Venn包获取黄芪甲苷与抑郁症的交集靶点基因,利用STRING网站与Cytoscape软件获得蛋白相互作用（PPI）网络,并通过R软件clusterprofile包对潜在作用靶点进行基因本体论（GO）和京都基因与基因组百科全书（KEGG）富集分析;使用Autodock Vina 1.1.2软件进行分子对接。结果 黄芪甲苷治疗抑郁症的相关靶点共107个,主要为丝裂原活化蛋白激酶1（MAPK1）、表皮生长因子受体（EGFR）和胱天蛋白酶3（CASP3）。这些核心靶点作用于钙离子信号通路、MAPK信号通路、磷脂酰肌醇-3-羟激酶（PI3K）-蛋白激酶B（Akt）信号通路以及神经活性配体–受体相互作用信号通路等发挥抗抑郁作用,分子对接显示黄芪甲苷能与核心靶点均能较好的结合。结论 黄芪甲苷治疗抑郁症具有多靶点、多通路协同的特点,可通过改善细胞凋亡、促进神经再生、调节神经炎症以及调节单胺类神经递质传递发挥协调抗抑郁作用。     

基于网络药理学和分子对接的薏苡附子散对类风湿性关节炎及慢性心力衰竭“异病同治”作用机制探讨

目的 基于网络药理学和分子对接方法探讨薏苡附子散治疗类风湿性关节炎(RA)及慢性心力衰竭(CHF)"异病同治"的作用机制。方法 通过中药系统药理学数据库与分析平台(TCMSP)数据库筛选薏苡附子散的活性成分,并利用 Pubchem 数据库获得 Smile 号,进而通过 Swiss Target Prediction 数据库获取活性成分对应的靶点。在 GeneCards 和 OMIM数据库平台预测 RA 及 CHF 疾病作用靶点。对活性成分靶点与疾病交集靶点进行蛋白质相互作用(PPI)网络构建及核心靶点筛选,并进行基因本体(GO)功能及京都基因与基因组百科全书(KEGG)通路富集分析。筛选核心成分和核心靶点,利用 AutoDock 软件进行分子对接验证。结果 从薏苡附子散中共筛选得到符合条件的活性成分 10 个,活性成分潜在作用靶点 403 个,RA 疾病靶点 1 112 个,CHF 疾病靶点 2 983 个,取交集,获得药物、疾病交集靶点 69 个。GO 富集分析结果显示主要与炎症反应的调节、MAPK 级联调控、对氧化应激的反应、骨化的调节、平滑肌细胞增殖等相关;KEGG 通路富集分析得到 236 条通路,与RA及CHF相关且排序较靠前的通路有 PI3K-Akt 信号通路、NF-κB 信号通路、MAPK 信号通路等。分子对接结果表明,薏苡附子散中的核心成分多根乌头碱、水黄皮素、豆甾醇具有与核心靶点 TNF、SRC、ESR1 和 PTGS2良好的结合潜力。结论 薏苡附子散治疗 RA 和 CHF 具有多靶点效应,涉及多条生物过程和信号通路,可能通过调控炎症反应、氧化应激反应、血管生成和发育、心脏收缩调节及 MAPK 级联调控等发挥"异病同治"作用。     

基于网络药理学和分子对接探讨大黄治疗脓毒症的作用机制

目的 基于网络药理学及分子对接技术探究大黄治疗脓毒症的作用机制。方法 通过中药系统药理学数据库与分析平台(TCMSP)获取大黄的有效活性成分及其作用靶点;应用Cytoscape 3.9.1构建大黄-活性成分-靶点的网络图;检索GeneCards、OMIM、Drugbank、TTD数据库,得到脓毒症相关靶点;通过建立维恩图获得中药与疾病交叉的关键靶点;应用STRING平台构建关键靶点蛋白质相互作用(PPI)网络图;使用DAVID数据库对关键靶点进行基因本体(GO)生物学富集分析及京都基因与基因组百科全书(KEGG)通路富集分析。最后,应用PyMOL软件和AutoDock Vina软件对大黄活性成分及其关键靶点进行分子对接验证。结果 获得大黄10种有效活性成分,其中重要的成分包括β-谷甾醇、芦荟大黄素、泽兰黄醇素等;药物靶点与疾病靶点交集后获得34个关键靶点,核心靶点有肿瘤坏死因子(TNF)、白细胞介素-1B(IL-1β)、肿瘤蛋白p53(TP53)、原癌基因(MYC)、半胱氨酸天冬氨酸蛋白酶-3(CASP3)、前列腺素内过氧化物合酶2(PTGS2)、过氧化物酶体增殖物激活受体G(PPARG)、转录因子AP-1(JUN)、雌激素受体1(ESR1)、半胱氨酸蛋白酶8(CASP8)。GO富集分析表明大黄的关键靶点主要富集于306个生物过程、29个细胞组成和61个分子功能;KEGG通路富集分析确定了111条相关信号通路,包括磷脂酰肌醇-3-羟激酶(PI3K)-蛋白激酶B(Akt)信号通路、丝裂原活化蛋白激酶(MAPK)信号通路、糖尿病并发症相关的晚期糖基化终末化产物(AGE)-晚期糖基化终末产物受体(RAGE)信号通路等;分子对接结果显示,大黄的主要活性成分芦荟大黄素与关键蛋白TNF、IL-1β、TP53、MYC、CASP3拥有良好的结合能力。结论 大黄通过多成分、多靶点和多通路治疗脓毒症。     

基于网络药理学和分子对接技术挖掘半贝丸治疗支气管炎的作用机制

目的 通过网络药理学及分子对接技术探讨半贝丸治疗支气管炎的分子作用机制。方法 基于TCMSP数据库结合文献报道筛选半贝丸的有效活性成分并预测作用靶点,构建半贝丸"成分-靶点"网络;运用GeneCards数据库和OMIM数据库获取支气管炎疾病靶点,构建韦恩图,获得半贝丸治疗支气管炎的作用靶点;采用Cytoscape软件构建"疾病-活性成分"网络模型;运用String平台将共同靶点进行蛋白相互作用(PPI)网络分析,通过Metascape数据库对靶点进行基因本体(GO)功能富集及基因组百科全书(KEGG)通路富集;并采用SwissDock在线数据库进行分子对接。结果 筛选得到半贝丸活性成分29个,共获得潜在靶点95个,支气管炎疾病靶点1 964个,半贝丸与支气管炎共同靶点49个。网络分析结果表明,半贝丸治疗支气管炎的关键靶点包括蛋白激酶(Akt1)、血管内皮生长因子A(VEGFA)、肿瘤抑制因子P53(TP53)、半胱氨酸蛋白酶3(CASP3)、原癌基因c-Jun产物(JUN)、基质金属蛋白酶-9(MMP9)等,主要通过细胞对有机环状化合物的反应、凋亡信号通路、转录调节复合物、半胱氨酸型内肽酶活性参与凋亡信号通路等生物过程发挥作用,KEGG富集主要涉及磷脂酰肌醇-3-激酶(PI3K)/Akt、细胞凋亡、晚期糖基化终末产物-晚期糖基化终末产物受体(AGE-RAGE)等信号通路。分子对接结果显示半贝丸中β-谷固醇、黄芩素、豆甾醇等关键化合物与Akt1、VEGFA、TP53、CASP3等关键靶点有较好的结合能力。结论 半贝丸治疗支气管炎具有多成分、多靶点和多通路等特征。     

基于网络药理学与分子对接技术新疆阿魏抗癌作用机制探讨

目的 采用网络药理学与分子对接技术探讨新疆阿魏Ferula sinkiangensisk抗癌的作用机制。方法 通过SymMap和SwissTargetPrediction 数据库筛选新疆阿魏的成分和靶点信息。利用 Genecards 数据库输入“cancer”关键词检索疾病的靶点;利用韦恩图获取药物-疾病的交集靶点,并借助STRING平台获取蛋白质-蛋白质相互作用（PPI）网络;利用DAVID数据库对药物-疾病的交集靶点进行基因本体（GO）富集分析和京都基因与基因组百科全书（KEGG）通路富集分析;利用Cytoscape 3.9.0软件绘制“活性成分-靶点-通路”网络图。利用 AutoDock软件对筛选出的主要活性成分及关键靶点进行分子对接实验,验证其结合活性。结果 获取新疆阿魏化学成分34个,对应靶点537个,通过筛选获得癌症靶点1 155个,药物-疾病的交集靶点134个。GO功能富集分析共获取331条条目（P＜0.05）,其中生物过程（BP）249条,细胞组成（CC）31条,分子功能（MF）51条。KEGG通路 133条,并建立活性成分-靶点-通路网络,分子对接实验表明活性物质阿魏酸、法尼斯淝醇 A、法尼斯淝醇 C、柠檬烯和 β -蒎烯与关键靶点 CCND1、JUN、CXCL8、PIK3CA 均具有较好的结合能 力 。 结论 新疆阿魏中阿魏酸、法尼斯淝醇 A、法尼斯淝醇 C、柠檬烯和 β-蒎烯等化学物质,通过 CCND1、JUN、CXCL8和PIK3CA等靶点,调节PDL-1表达和PD-1免疫检查点通路、IL-17信号通路、雌激素信号通路和PI3K-Akt信号通路等发挥抗癌作用。     

橘红痰咳液联合复方甲氧那明治疗感染后咳嗽的疗效观察

目的 运用网络药理学研究芍药甘草汤治疗乙型病毒性肝炎所致肝损伤的作用机制。方法 通过中药系统药理学数据库与分析平台（TCMSP）获取芍药甘草汤的化合物及靶点,以口服生物利用度（OB）≥30%和类药（DL）≥0.18为阈值进行化合物筛选,将靶点输入Uniprot获取靶点对应的基因Symbol;从TTD、OMIM等数据库获取乙型病毒性肝炎的相关靶点并筛选出与芍药甘草汤靶点基因的交集基因;运用Cytoscape3.8.0软件绘制活性成分-靶点、疾病-中药-化合物-交集靶点（基因）网络图;运用String构建蛋白相互作用网络,再用R语言的Bioconductor安装包,进行GO富集及KEGG通路富集分析,并联合主要化合物、交集基因与通路分析结果,绘制成分-靶点-通路网络图;用Vina软件对筛选出来的结果进行分子对接。结果 筛选得到芍药甘草汤有效成分105种、有效成分靶点214个;筛选得到乙型病毒性肝炎疾病靶点5 984个,药物-疾病交集基因198个;经蛋白互作网络及拓扑结构分析得到21个核心靶点,121条相互作用关系;槲皮素、山柰酚、柚皮素等为芍药甘草汤的主要活性成分,PPARA、RB1、TP53、MAPK3、AKT1、STAT3、JUN等为主要作用靶点。GO富集分析显示靶点所在的细胞组分主要为薄膜筏、膜微域、膜区域;生物学过程主要富集在有对金属离子的响应、对脂多糖的反应;分子功能主要为核受体活性、转录因子活性。KEGG富集发现膜区由糖基化终末产物介导的AGE-RAGE通路、乙型肝炎通路等为主要通路。进一步筛选核心靶点及化合物成分进行分子对接显示MAPK3、AKT1、STAT3、JUN作为核心靶点可与槲皮素、山柰酚、柚皮素稳定对接。结论 通过网络药理学及分子对接的方法,找到了芍药甘草汤治疗慢性乙型病毒性肝炎肝损伤可能的潜在靶点,预测了其发挥药理作用的关键通路。     

基于网络药理学研究白芍治疗肝纤维化的作用机制

目的 基于网络药理学方法探讨白芍治疗肝纤维化的可能作用机制。方法 使用TCMSP数据库筛选出白芍的活性成分。借助PubChem和Swiss Target Prediction数据库预测白芍有效成分的潜在作用靶点。运用GeneCards及OMIM数据库筛选肝纤维化对应靶点,利用Venn2.1.0获得白芍与肝纤维化疾病的共同靶点。使用Cytoscape3.9.0软件构建“白芍-有效成分-交集靶点-肝纤维化”网络图,预测主要活性部位,使用String数据库绘制PPI网络。利用DAVID数据库对有效作用靶点进行GO分析及Pathway中的KEGG进行富集分析。结果 筛选得到白芍有效成分6个,作用靶点213个;肝纤维化靶点155个;白芍治疗肝纤维化的靶点49个;主要活性成分是山萘酚、芍药苷、白桦脂酸及β-谷甾醇。GO富集分析显示269个生物过程、30个细胞组成、64个分子功能,KEGG通路富集分析共67条通路。结论 通过网络药理学方法初步研究白芍抗肝纤维化的作用机制,表明白芍具有多成分、多通路、多靶点等的作用特点,为进一步相关实验研究提供参考。     

Synthesis and evaluation of 2,6-piperidinedione derivatives as potentially novel compounds with analgesic and other CNS activities

New 2,6-piperidinediones 2_a–g and 4_a–d were prepared by initial condensation of aromatic aldehydes or cycloalkanones with cyanoacetamide to give α-cyanocinnamides l_a–g or cycloalkylidenes 3_a,b which underwent Michae1 addition with ethyl cyanoacetate or diethylmalonate. Compounds 4_a–d were alkylated by various alkyl halides to produce the N-alkylated 2,6-piperidinedione derivatives 5_a–m. Some new selected compounds 2_a–c,f, 4_a–d & 5_e,h,j were pharmacologically evaluated for potential anticonvulsant, sedative and analgesic activities. These compounds exhibited significant anticonvulsant and analgesic effects after a single I.P. administration 100 mg/kg b.wt. . On the other hand all the investigated compounds induced hypnotic activity and prolonged the phenobarbital sodium- induced sleep as compared with the control group and the most potent compound was found to be 2_f.     

NEURAMIDE STIMULATES ADRENOCORTICOTROPIN BUT NOT PROLACTIN RELEASE FROM RAT PITUITARY

Neuramide (NMD), a substance found in crude preparations of porcine stomach extract, is a viral inhibitor that also has putative immunostimulatory effects. The effects of NMD on stress-hormone (ACTH and prolactin—PRL) release were assessed inin vivoandin vitrostudies. In the former, blood levels of corticosterone and PRL were measured in NMD-treated male rats.In vitroexperiments were performed to evaluate the effects of NMD and three of its fractions (obtained with high performance liquid chromatography) on ACTH and PRL release from perfused rat pituitary slices. NMD increased plasma corticosterone levelsin vivoand produced dose-dependent increases inin vitropituitary release of ACTH. No effects on PRL secretion were observedin vivoorin vitro. The stimulatory effects on ACTH release were caused by the NMD fraction with a molecular weight of >5000<10000Da.     

EFFECT OF POLICOSANOL SUCCESSIVE DOSE INCREASES ON PLATELET AGGREGATION IN HEALTHY VOLUNTEERS

Policosanol is a cholesterol-lowering drug with hypocholesterolemic effects demonstrated in experimental models, healthy volunteers and type II hypercholesterolemic patients. In addition, antiplatelet effects of policosanol have been shown in experimental models and healthy volunteers. The effect of successively increasing doses of policosanol on platelet aggregation was investigated in a randomized, placebo-controlled, double-blind study conducted in 37 healthy volunteers. The volunteers were on a placebo-baseline period (two tablets per day) for 7 days and thereafter they received randomly, under double-blind conditions, placebo or policosanol (10mgday⁻¹) for 7 days. After this period dosage was doubled to 20mgday⁻¹for the next 7 days and then again doubled to 40mgday⁻¹, while the control group received placebo tablets all the time. Platelet aggregation as well as coagulation time was measured at baseline and after each dosing step. Results showed that antiplatelet effects of policosanol were successfully enhanced throughout the study, thus suggesting a dose-dependent relationship. No significant effect was reached during the first dosing period, but significant reductions of epinephrine and ADP-induced platelet aggregation were observed after the second one. Finally, a significant inhibition of platelet aggregation induced by all the agonists was observed at the last dosing step. Coagulation time remained unchanged during the trial.     

鼻渊净胶囊的HPLC指纹图谱研究

目的 建立鼻渊净胶囊的高效液相色谱（HPLC）指纹图谱。方法 采用Agilent SB-C₁₈（4.6 mm×250 mm,5 μm）色谱柱,乙腈-水为流动相、以1.0 ml/min流速行梯度洗脱,检测波长210 nm,柱温30 ℃,洗脱时间为80 min。采用中药色谱指纹图谱相似度评价系统（2004A版）对检测出色谱进行指纹图谱相似度评价。结果 建立了鼻渊净胶囊的HPLC指纹图谱,确定了20个共有峰,15个峰归属到各药材,其中5个峰确认了化学成分;10批样品的指纹图谱的整体相似度与对照图谱比较,均在90%以上。结论 所建立的鼻渊净胶囊指纹图谱有助于从整体上控制该制剂的质量。     

INDIRECT PARASYMPATHOMIMETIC ACTIVITY OF THE CLASS III ANTIARRHYTHMIC SUBSTANCE / -SOTALOLIN VITRO: REVERSIBLE INHIBITION OF CHOLINESTERASE ISOENZYMES FROM BLOOD AND THE HUMAN CENTRAL NERVOUS SYSTEM

Inhibitory effects of the class III antiarrhythmic compound / -sotalol on acetylcholinesterase (AChE; EC 3.1.1.7) isoenzymes of both erythrocytes and the human caudate nucleus and on serum cholinesterase (ChE; EC 3.1.1.8) were studiedin vitrousing a spectrophotometric kinetic assay with acetylthiocholine (ASCh) as substrate. Sotalol concentrations in the assays varied from 0.32 to 3.2m . All isoenzymes studied were inhibited by / -sotalol in a reversible and concentration-dependent manner. Double reciprocal plots of the reaction velocity against varying ASCh concentrations revealed that / -sotalol reduced substrate affinity (apparent Michaelis constant, KM, increased) of serum ChE, but did not change the enzyme's maximal rate of ASCh hydrolysis (V_max). Thus, / -sotalol inhibition of serum ChE was of the competitive type (rate constant for reversible competitive inhibition: K_i=0.51m ). In contrast, / sotalol reduced the maximal reaction velocity of the AChE isoenzyme from the central nervous system (caudate nucleus), but had no influence on substrate affinity of the enzyme (K_Mwith ASCh unchanged) indicating purely non-competitive inhibition kinetics (rate constant of reversible non-competitive inhibition: K_i′=0.44m ). / -sotalol inhibition of erythrocyte AChE was of mixed competitive/non-competitive type (K_i=0.31m , K_i′=0.49m ). Non-competitive / -sotalol inhibition of caudate nucleus AChE and the non-competitive component of erythrocyte AChE inhibition cannot be overcome by increased concentrations of the cholinergic transmitter acetylcholine (ACh). Peak / -sotalol plasma levels as described in the literature for both humans (15μ ) and experimental animals (dogs: 18μ ; rats: 260μ ) as well as maximal myocardial concentrations of the substance (dogs: 46μ ; rats: 478μ ) are in the range of about 2% to 100% of the sotalol inhibition rate constants determined in the present paper for cholinesterase isoenzymesin vitro. Thus, / -sotalol inhibition of ACh hydrolysisin vivomay contribute to both the well known antiarrhythmic potential and proarrhythmic side effects of the compound.     

Investigation of the prevalence of tetQ, tetX and tetX1 genes in Bacteroides strains with elevated tigecycline minimum inhibitory concentrations

In this study, the antibiotic susceptibilities to tigecycline and tetracycline of 35 selected Bacteroides fragilis group strains were determined by Etest, and the presence of tetQ, tetX, tetX1 and ermF genes was investigated by polymerase chain reaction (PCR). tetQ was detected in all 12 B. fragilis group isolates (100%) exhibiting elevated tigecycline minimum inhibitory concentrations (MICs) (≥8 μg/mL) as well as the 8 strains (100%) with a tigecycline MIC of 4 μg/mL, whilst tetX and tetX1 were present in 15% and 75% of these strains, respectively. All of these strains were fully resistant to tetracycline (MIC ≥ 16 μg/mL). On the other hand, amongst the group of strains with tigecycline MICs < 4 μg/mL (15 isolates), tetQ, tetX and tetX1 were found less frequently (73.3%, 13.3% and 46.7%, respectively). All but two strains harbouring the tetQ gene in this group were non-susceptible to tetracycline, with a MIC > 4 μg/mL. These data suggest that in most cases tigecycline overcomes the tetracycline resistance mechanisms frequently observed in Bacteroides strains. However, the presence of tetX and tetX1 genes in some of the strains exhibiting elevated MICs for tigecycline draws attention to the possible development and spread of resistance to this antibiotic agent amongst Bacteroides strains. The common occurrence of ermF, tetX, tetX1 and tetQ genes together predicted the presence of the CTnDOT-like Bacteroides conjugative transposon in this collection of Bacteroides strains.     

AMELIORIATION OF CHEMICALLY-INDUCED HEPATOCYTE INJURY BY CYCLOSPORINE A

Cyclosporine A, beside its current applications, possesses potential hepatoprotective effects. This study was directed to investigate the effect of Cyclosporine A pretreatment on hepatic injury due to carbon tetrachloride (CCl₄) and -galactosamine. Rats were injected by two successive doses of Cyclosporine A (5mgkg⁻¹day⁻¹). Six hours after the second dose, 1mlkg⁻¹of CCl₄was administered i.p. Effects associated with Cyclosporine A pretreatment were examined by using isolated hepatocytes and hepatocytes that were immobilized and continuously perfused. -Galactosamine (5m ) was added directly to the perfusion medium. After isolation, hepatocytes were examined histologically by light and electron microscopy, immobilized and perfused for further metabolic functional activity evaluation. Cyclosporine A pretreatmentin vivoproduced hepatoameliorative effects of various degrees which were statistically significant as manifested by: (1) an increased trypan blue exclusion after CCl₄; (2) an improved ureagenesis after CCl₄; (3) a reduction in the lipid droplets accumulation in the cytoplasm produced by CCl₄administration; (4) well preserved cytoplasmic organelles as mitochondria, endoplasmic reticulum ER, nuclear chromatin structures that were altered by CCl₄; and (5) an increased hepatocytes survival in the agarose gel matrix, reduction of LD leakage and improvement of ureagenesis after -galactosamine addition to the perfusion medium. The beneficial effect of Cyclosporine A pretreatment in modifying hepatotoxicity of chemical insults merits further studies.     

喙果黑面神化学成分研究

目的研究大戟科植物喙果黑面神(Breynia rostrata Merr.)的化学成分。方法利用硅胶、凝胶等色谱技术分离纯化化学成分,根据化合物的理化性质和光谱数据进行结构鉴定。结果从喙果黑面神的正丁醇萃取部分分离得到4个化合物,分别鉴定为6-O-甲基丙酰基-α-D-吡喃葡糖(6-O-methylpropanoyl-α-D-glucopyranose,1);4″-苯酚基-6-O-甲基丙酰基-β-D-吡喃葡糖苷(4″-phenolic-6-O-methylpropanoyl-β-D-glucopyranoside,2);1-O-没食子酰基-β-D-吡喃葡糖苷(1-O-galloyl-β-D-glucopyranoside,3);熊果苷(arbutin,4)。结论化合物1和2为新化合物,3和4均为首次从该种植物分离得到。     

EFFECTS OF 2-GUANIDINE-4-METHYLQUINAZOLINE ON GASTRIC ACID SECRETION IN RATS

In this study 2-guanidine-4-methylquinazoline (2-GMQ) appeared to decrease basal and stimulated gastric acid secretion, while structurally related compounds as dimethyl- biguanide, cyanoguanidine and 2-cyanoamino-4-methylpyrymidine did not. Thus, there is an antisecretory effect when the biguanide group is associated with a lipophilic structure. The antisecretive effects exerted by 2-GMQ are associated with anti H₂-histamine activity.The anti H₂-histamine nature of the effects of 2-GMQ was confirmed by the capacity of this compound of depressing the chronotropic activity of the isolated guinea pig auricle increased by histamine, as well as relaxant activity in rat uterus contracted by histamine, since both preparations are rich in H₂-histamine receptors.     

Effect of bay K 8644, a calcium channel agonist,on dog cardiac muscarinic receptors

To investigate further whether the effects of the dihydropyridine (DHP) drugs on calcium channels are related to those of these drugs on muscarinic receptors, the binding characteristics of the DHP calcium channel agonist, Bay K 8644, on muscarinic receptors and calcium channels were compared to those of the DHP calcium channel antagonists, nicardipine and nimodipine in the dog cardiac sarcolemma. Bay K 8644, nicardipine and nimodipine inhibited the specific [³H]QNB binding with K _i values of 16.7μM, 3.5μM and 15.5μM respectively. Saturation data of [³H]QNB binding in the presence of these DHP drugs showed this inhibition to be competitive. Bay K 8644, like nicardipine and nimodipine, blocked the binding of [³H]nitrendipine to the high affinity DHP binding sites, but atropine did not, indicating that the muscarinic receptors and the DHP binding sites on calcium channels are distinct. The K _i value of Bay K 8644 for the DHP binding sites was 4 nM. Nicardipine and nimodipine (K _i :0.1–0.2 nM) were at least 20 times more potent than Bay K 8644 in inhibiting [³H]nitrendipine binding. Thus, the muscarinic receptors were about 4000 times less sensitive than these high affinity DHP binding sites to Bay K 8644. These results suggest that the DHP calcium agonist Bay K 8644 binds directly to the muscarinic receptors but its interaction with the muscarinic receptors is not related to its binding to the DHP binding sites on calcium channels.