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1.
目的 探讨前列闭尔通栓对自身免疫性前列腺炎(EAP)大鼠的影响及作用机制。方法 50只SD大鼠采用前列腺蛋白提纯液联合完全弗氏佐剂制备EAP大鼠模型,另取10只作为对照组,造模成功大鼠随机分为模型组、前列通栓(0.42 g·只-1)组和前列闭尔通栓低、中、高剂量(0.33、0.66、0.99 g·只-1)组,直肠给药28 d。压力换能器测定膀胱内压变化速率,显微镜计数测定前列腺液中卵磷脂小体、白细胞数量,ELISA法检测前列腺组织炎症因子,HE染色观察前列腺组织病理变化,Westernblotting检测前列腺组织核因子κB(NF-κB)p65、磷酸化κB抑制因子激酶(p-IKK-α)/IKK-α、肿瘤坏死因子-α(TNF-α)、磷酸化IκB激酶-α(p-IκB-α)/IκB-α、环氧化酶-2(COX-2)蛋白表达;实时荧光定量PCR(qRT-PCR)法检测重组人趋化因子配体5(CXCL5)、白细胞介素-6(IL-6)、TNF-α、COX-2基因表达。结果 与对照组比较,模型组大鼠膀胱内压变化速率显著降低(P<0.01);白细胞数量显著增加、卵磷脂小体数量显著减少(P<0.01);前列腺组织TNF-α、IL-8水平显著升高(P<0.01),IL-10水平显著降低(P<0.01);前列腺组织炎症反应明显,病理评分显著升高(P<0.01);前列腺组织NF-κB p65、p-IKK-α、p-IκB-α、TNF-α、COX-2蛋白表达显著升高(P<0.05、0.01);前列腺组织CXCL5、COX-2、TNF-α基因表达升高(P<0.05)。与模型组比较,前列闭尔通栓中剂量组膀胱内压变化速率显著升高(P<0.01);各剂量组白细胞数量显著减少、卵磷脂小体数量显著增加(P<0.01);中、高剂量组TNF-α、IL-8水平显著降低(P<0.05、0.01);各剂量组前列腺组织炎症反应明显减轻,病理评分显著降低(P<0.01);各剂量组前列腺组织p-IκBα/IκBα、COX-2蛋白表达显著降低(P<0.01);低剂量组前列腺组织p-IKK-α/IKK-α蛋白表达显著降低(P<0.05);低、高剂量组前列腺组织NF-κB p65蛋白表达显著降低(P<0.05);中剂量组前列腺组织TNF-α蛋白表达显著降低(P<0.05) ;各剂量组前列腺组织CXCL5、IL-6、COX-2基因表达显著降低(P<0.05)。结论 前列闭尔通栓可有效改善EAP大鼠前列腺组织病理形态,减轻炎症反应,其作用机制可能与抑制NF-κB信号通路相关蛋白NF-κB p65、p-IKK-α、TNF-α、p-IκB-α表达相关。  相似文献   

2.
目的 探究清脑片对沙鼠脑缺血再灌注的保护作用及其机制。方法 采用双侧颈总动脉结扎10 min再灌注60 min,建立沙鼠脑缺血模型,观察高、中、低剂量清脑片组(1.5,0.75,0.375 g·kg-1)对沙鼠脑组织中白介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)、兴奋性氨基酸谷氨酸(Glu)、天门冬氨酸(Asp)、血栓烷素B2(TXB2)、丙二醛(MDA)含量及ATP活性和NF-кB免疫阳性表达的影响。结果 与模型组比较,高、中剂量清脑片可显著降低脑组织中IL-1β、TNF-α、Glu、Asp、TXB2、MDA的含量及NF-κB免疫阳性表达水平(P<0.01或P<0.05),显著提高脑组织中Na+-K+-ATP、Mg2+-ATP、Ca2+-ATP、Ca2+-Mg2+-ATP的酶活性(P<0.01或P<0.05)。结论 清脑片对沙鼠脑缺血再灌注有明显的保护作用,其作用机制可能与抑制体内炎症因子、过氧化能力及提高酶活力有关。  相似文献   

3.
目的 探究荜铃胃痛颗粒对乙醇诱导胃溃疡模型大鼠的保护作用。方法 SD大鼠随机分为对照组、模型组及荜铃胃痛颗粒低、中、高剂量(0.79、1.58、3.16 g·kg-1)组和西咪替丁(42.00 mg·kg-1,阳性药)组,每组8只;各组均按剂量预给药8 d,对照组和模型组大鼠ig等体积0.5%羧甲基纤维素钠(CMC-Na)溶液。末次给药30 min后,除对照组外,其余大鼠ig给予1 mL无水乙醇造模,1 h后牺牲动物取材;展开胃黏膜面拍照,测量溃疡面积,取部分胃组织进行HE染色;检测血清中白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)和超氧化物歧化酶(SOD)水平,检测胃组织中髓过氧化物酶(MPO)和前列腺素E2(PGE2)水平。结果 与对照组比较,模型组大鼠胃溃疡面积和胃黏膜病理评分显著升高(P<0.001),大鼠血清中IL-1β(P<0.01)和TNF-α(P<0.05)水平均显著升高,大鼠胃组织MPO活力显著升高(P<0.001),大鼠胃组织中PGE2水平显著降低(P<0.01)。与模型组比较,各给药组大鼠胃溃疡面积和胃黏膜病理评分显著降低(P<0.05、0.01、0.001)。与模型组比较,荜铃胃痛颗粒组大鼠血清IL-1β和TNF-α水平显著降低(P<0.05、0.001),胃组织中MPO活力显著降低(P<0.01、0.001),血清SOD活力显著升高(P<0.05);胃组织PGE2水平显著增加(P<0.05)。结论 荜铃胃痛颗粒可通过抑制炎症因子分泌、缓解机体氧化应激、保护胃黏膜等发挥对胃溃疡模型大鼠的保护作用。  相似文献   

4.
李萍  姬白嫣  魏娟  杜小敬  黄凤 《肿瘤药学》2021,11(6):701-706
目的 探索藏红花素联合顺铂对人宫颈癌HeLa细胞的协同抑制作用及相关调控机制。方法 取对数生长期人宫颈癌HeLa细胞,设置空白对照组(DMSO)、藏红花素组(400 μg·mL-1)、顺铂组(5 μg·mL-1)、联合组(藏红花素400 μg·mL-1+顺铂5 μg·mL-1)。干预48 h后,CCK-8检测HeLa细胞增殖抑制率,采用CompuSyn软件计算藏红花素与顺铂的联合指数(CI),Annexin V-FITC染色法检测细胞凋亡,流式细胞术检测细胞周期分布,Western blotting检测激活型半胱氨酸天冬氨酸蛋白酶-3(Cleaved Caspase-3)、B细胞淋巴瘤/白血病-2(Bcl-2)、Bcl-2相关X蛋白(Bax)、细胞周期素D1(Cyclin D1)、周期蛋白依赖激酶2(CDK2)的表达。结果 与顺铂组比较,联合组细胞增殖抑制率显著升高(P<0.05),CI为0.68,具有中度协同效应;细胞凋亡率显著升高(P<0.01),G0/G1期细胞比例显著升高(P<0.05),而G2/M期比例显著降低(P<0.01),Cleaved Caspase-3、Bax蛋白表达水平及Bax/Bcl-2比值均显著升高(P<0.05),Cyclin D1、CDK2蛋白表达水平显著降低(P<0.01)。与空白对照组比较,藏红花素组G0/G1期细胞比例显著升高而G2/M期比例显著降低(P<0.01),Cleaved Caspase-3、Bax表达水平及Bax/Bcl-2比值均显著升高(P<0.01),Cyclin D1、CDK2表达水平显著降低(P<0.05)。结论 藏红花素联合顺铂可协同抑制人宫颈癌HeLa细胞的增殖和生长,其作用机制可能与调控凋亡相关蛋白的表达从而促进细胞凋亡、阻滞细胞周期进程有关。  相似文献   

5.
目的 研究间充质干细胞注射液(MSCsI)对手术法诱导的大鼠膝骨关节炎的治疗作用。方法 自70只大鼠中随机取8只为假手术组,其余62只动物均进行右侧膝关节单侧手术造模。术后4周,进行X光检查并进行K-L评分,选择模型成功、状态良好的模型动物40只,根据K-L评分随机分为模型组、玻璃酸钠(阳性药,每关节腔0.5 mg玻璃酸钠注射液)组和MSCsI低、中、高剂量(每关节腔1.5×105、5.0×105、1.5×106个细胞)组,每组8只。分组后次日开始,玻璃酸钠组每周1次,其余各组每2周1次,关节腔内注射给药,持续5周,假手术组与模型组给予等体积0.9%氯化钠溶液。使用X射线机检测大鼠膝关节病变;给药后记录大鼠行为学及痛阈变化;剖杀时记录关节软骨大体评分;试剂盒法检测血清中白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、转化生长因子β(TGF-β)、II型胶原C端肽(CTX-Ⅱ)、前列腺素E2(PGE2)水平;取膝关节组织进行病理切片,HE染色、甲苯胺蓝染色观察组织损伤。结果 与模型组相比,MSCsI高剂量显著降低大鼠X光评分(P<0.05)、降低大鼠关节软骨大体观察评分(P<0.05);给药4周后,MSCsI低、中、高剂量显著降低大鼠行为学评分(P<0.05、0.01),中、高剂量显著升高大鼠痛阈值(P<0.01);MSCsI低剂量显著降低血清中IL-1β水平、升高TGF-β水平(P<0.05),中剂量显著降低血清中IL-1β、IL-6、CTX-Ⅱ水平、升高TGF-β水平(P<0.05、0.01),高剂量显著降低血清中IL-1β、IL-6、CTX-Ⅱ、PGE2水平、升高TGF-β水平(P<0.05、0.01);HE染色结果显示,MSCsI各剂量能有效减轻模型大鼠组织病理学改变,滑膜、软骨及软骨下骨病变较轻;甲苯胺蓝染色显示,MSCsI各剂量可减小模型大鼠软骨基质损伤。结论 MSCsI每2周1次关节腔内注射对手术诱导的大鼠膝骨关节炎有明显的治疗作用。  相似文献   

6.
王淑静  黄冬梅  王立  谢雯 《药学研究》2023,42(11):870-874,880
目的 基于能量代谢探究白藜芦醇对H2O2诱导的人神经母细胞瘤SH-SY5Y细胞氧化损伤的保护作用。方法 选取20、10、5、1 μmol•L-1的白藜芦醇(Res)处理SH-SY5Y细胞24 h后,加入1.2 mmol•L-1的H2O2,继续培养24 h,采用MTT法测定细胞活力,流式细胞术检测细胞凋亡率,试剂盒检测糖代谢相关酶己糖激酶(HK)、磷酸果糖激酶(PFK)、丙酮酸激酶(PK)、琥珀酸脱氢酶(SDH)、乳酸脱氢酶(LDH)活力以及葡萄糖消耗量、ATP含量,Western blot法检测低氧诱导因子1α(HIF-1α)和葡萄糖转运体1(GLUT-1)表达。结果 1.2 mmol•L-1的H2O2造成SH-SY5Y细胞氧化损伤,细胞活力降低,细胞凋亡率升高(P<0.01);与H2O2氧化损伤组相比,20、10、5 μmol•L-1白藜芦醇组细胞活力升高,细胞凋亡率显著降低(P<0.01);PFK、PK、SDH活力及ATP含量、葡萄糖消耗量显著升高,HK活力和细胞外LDH活力明显降低(P<0.01);GLUT-1表达量显著升高,HIF-1α表达量显著降低(P<0.01)。结论 20、10、5 μmol•L-1的白藜芦醇调控GLUT-1和HIF-1α蛋白表达,提高细胞糖代谢酶活力,增加产能,对H2O2诱导的SH-SY5Y细胞氧化损伤发挥保护作用。  相似文献   

7.
目的 探讨曲普瑞林联合他莫昔芬治疗子宫肌瘤的临床疗效及对血清转化生长因子-β1(TGF-β1)、血管内皮生长因子(VEGF)、缺氧诱导因子-1α(HIF-1α)水平的影响。方法 选取2018年5月—2020年5月聊城市第二人民医院收治的140例子宫肌瘤患者作为研究对象,根据治疗方法分为对照组(70例)和观察组(70例)。对照组患者口服枸橼酸他莫昔芬片,1片/次,1次/d。观察组患者在对照组基础上肌内注射注射用醋酸曲普瑞林,月经周期开始的第3~5天肌内注射1次,之后每隔28 d注射1次,3.75 mg/次。两组均治疗3个月。观察两组临床疗效、不良反应,并比较治疗前后子宫体积、肌瘤体积及血清促卵泡激素(FSH)、雌二醇(E2)、孕酮(P)、TGF-β1、VEGF、HIF-1α水平。结果 治疗后,观察组总有效率为91.43%,明显高于对照组的75.71%(P<0.05)。治疗后,两组患者子宫体积、肌瘤体积均明显小于治疗前(P<0.05),且观察组患者子宫体积、肌瘤体积均明显小于对照组(P<0.05)。治疗后,两组患者血清FSH、E2、P水平均明显低于治疗前(P<0.05),且观察组患者血清FSH、E2、P水平均明显低于对照组(P<0.05)。治疗后,两组患者血清TGF-β1、VEGF、HIF-1α水平均明显低于治疗前(P<0.05),且观察组患者血清TGF-β1、VEGF和HIF-1α水平均明显低于对照组(P<0.05)。治疗期间,两组不良反应发生率相比差异无统计学意义。结论 在他莫昔芬基础上联用曲普瑞林治疗子宫肌瘤,可提高疗效,缩小子宫、肌瘤体积,明显降低血清雌激素、TGF-β1、VEGF、HIF-1α水平,且具有一定安全性。  相似文献   

8.
目的 考察三七总皂苷(PNS)的体内外抗肺纤维化作用,并探讨其作用机制。方法 将60只Wistar大鼠随机分为假手术组、模型组、吡非尼酮(阳性药,50 mg·kg-1)组和PNS低、中、高剂量(50、100、200 mg·kg-1)组,采用气管内注入博来霉素(5 mg·kg-1)建立肺纤维化大鼠模型,假手术组注入生理盐水;造模24 h后给药,持续28 d;检测大鼠肺脏系数,利用BUXCO系统检测大鼠气道阻力与肺顺应性变化,HE染色后观察大鼠肺组织病理结构损伤,免疫荧光法检测大鼠肺组织E-钙黏蛋白(E-cad)、N-钙黏蛋白(N-cad)表达,免疫组化法检测大鼠肺组织蛋白酶激活受体-1(PAR-1)蛋白表达;体外培养人胚肺成纤维细胞MRC-5,设对照组、模型组(凝血酶2 U·mL-1建立体外肺纤维化模型)和PNS 5、10、20 μg·mL-1组,体外划痕实验检测细胞迁移率,实时荧光定量PCR(qRT-PCR)、Western blotting实验检测α-平滑肌肌动蛋白(α-SMA)、波形蛋白(Vim)和PAR-1基因和蛋白表达水平;随后使用PAR-1 si RNA抑制PAR-1表达后,进一步采用qRT-PCR和Western blotting检测α-SMA与Vim基因与蛋白表达。结果 体内实验中,与模型组相比,PNS各剂量组肺脏系数显著降低(P<0.001)、肺顺应性显著升高(P<0.05、0.01、0.001),100、200 mg·kg-1 PNS组大鼠气道阻力显著降低(P<0.05、0.01),同时PNS能够改善大鼠肺组织的病理结构损伤,在下调N-cad的蛋白表达同时上调E-cad的蛋白表达,且100、200 mg·kg-1 PNS组PAR-1蛋白表达显著下调(P<0.01、0.001)。体外实验中,与模型组相比,10、20 μg·mL-1 PNS组细胞的迁移率显著降低(P<0.01、0.001),20 μg·mL-1 PNS组α-SMAVim mRNA水平下调(P<0.05、0.01),20 μg·mL-1 PNS组α-SMA蛋白表达水平显著下调(P<0.05) ,10、20 μg·mL-1 PNS组Vim蛋白表达水平显著下调(P<0.05、0.01),PAR-1 siRNA组α-SMA mRNA水平和α-SMA、Vim蛋白表达水平显著降低(P<0.05、0.01、0.001)。结论 PNS具有抗肺纤维化的作用,其机制可能与调控PAR-1的异常有关。  相似文献   

9.
目的 探讨人参皂苷Rb1对小鼠脑缺血再灌注诱导的血脑屏障(BBB)损伤的作用及机制。方法 将C57BL/6小鼠随机分为假手术组、模型组和人参皂苷Rb1低、中、高剂量(5、10、20 mg·kg-1)组,采用线栓法栓塞颈内动脉1 h后复灌建立脑缺血再灌注损伤模型,假手术组不栓塞,其余操作同模型小鼠。缺血1 h后ip相应药物,于再灌注24 h后处死取材。采用伊文思蓝染色法检测各组小鼠BBB损伤程度;采用实时荧光定量PCR (qRT-PCR)法检测各组小鼠脑组织中炎症因子白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)以及紧密连接蛋白1(ZO-1)、闭合蛋白(Occludin)的mRNA表达水平;同时采用Western blotting检测各组小鼠脑组织中ZO-1、Occludin蛋白,金属基质蛋白酶-2(MMP-2)、基质金属蛋白酶-9(MMP-9)以及MAPK通路相关蛋白磷酸化的表达水平。结果 与模型组相比,人参皂苷Rb1可显著减少脑缺血再灌注小鼠脑组织中伊文思蓝的渗漏量(P<0.05),显著降低脑组织中IL-1β、IL-6TNF-α的mRNA转录水平(P<0.05、0.01);显著上调ZO-1和Occludin的mRNA转录和蛋白表达水平(P<0.05、0.01);显著降低MMP-2、MMP-9的蛋白表达水平(P<0.05、0.01);显著抑制MAPK通路p38、JNK及ERK磷酸化蛋白的表达(P<0.05、0.01)。结论 人参皂苷Rb1对小鼠脑缺血再灌注诱导的BBB损伤具有一定的改善作用,其作用机制可能与抑制MAPK信号通路激活,减少MMP-2、MMP-9蛋白的表达,进而减轻对ZO-1、Occludin等紧密连接蛋白的降解有关。  相似文献   

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目的 分析脾氨肽口服冻干粉联合阿奇霉素治疗小儿肺炎支原体感染的疗效及对免疫功能的影响。方法 以2013年5月—2016年6月开封市儿童医院诊治的肺炎支原体感染患儿106例为研究对象,根据入组的先后顺序分为观察组和对照组,每组53例。对照组患儿采用阿奇霉素序贯治疗,观察组在对照组的基础上加用脾氨肽口服冻干粉,均治疗3周。比较两组的临床疗效、T细胞亚群(CD4+、CD8+、CD4+/CD8+)水平、细胞因子(IL-10、IL-17、TGF-β1)水平及安全性。结果 观察组的临床总有效率为94.39%,显著高于对照组的79.25%,差异有统计学意义(P<0.05)。治疗后,两组的CD4+、CD4+/CD8+较治疗前显著升高(P<0.05),且观察组的显著高于对照组,差异有统计学意义(P<0.05);CD8+较治疗前显著降低(P<0.05),且观察组的显著低于对照组,差异有统计学意义(P<0.05)。治疗后,两组的IL-10、IL-17、TGF-β1水平均较治疗前显著降低(P<0.05),且观察组的显著低于对照组,差异有统计学意义(P<0.05)。两组不良反应发生率比较,差异无统计学意义。结论 脾氨肽口服冻干粉联合阿奇霉素治疗小儿肺炎支原体感染的临床疗效显著,安全可靠,可显著提高机体的细胞免疫功能,同时降低免疫损伤。  相似文献   

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Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.
Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.
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This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.  相似文献   

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Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.  相似文献   

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Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.  相似文献   

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In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.  相似文献   

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