神经刺激仪定位下腰丛联合坐骨神经阻滞对下肢手术患者血液动力学及应激反应的影响

目的:探讨神经刺激仪定位下腰丛联合坐骨神经阻滞对下肢手术患者血液动力学、应激反应的影响。方法:选取福建医科大学附属南平第一医院2014年1月-2015年6月收治的单侧下肢手术患者60例,依据不同的麻醉方法分为对照组(n=29)和研究组(n=31),对照组给予硬膜外麻醉,研究组于神经刺激仪定位下行腰丛联合坐骨神经阻滞,对比两组患者的麻醉效果,同时对比患者在麻醉前(T0)、麻醉后5 min(T1)、麻醉后15 min(T2)、麻醉后30 min(T3)、术毕(T4)时的血液动力学指标以及术前(Ta)、术中(Tb)、术毕(Tc)时的应激反应情况,并对比两组不良反应发生情况。结果:研究组优良率为96.77%,与对照组的93.10%对比差异无统计学意义(P0.05)。研究组T1、T2、T3、T4时平均动脉压(MAP)、心率(HR)与T0时比较,差异无统计学意义(P0.05),对照组T2、T3时MAP低于T0时,T1、T2、T3、T4时HR低于T0时,且均低于研究组,差异有统计学意义(P0.05)。Ta、Tc时,两组血糖(GLU)、皮质醇(Cor)、儿茶氨酚(CA)水平比较差异无统计学意义(P0.05),Tb时两组GLU、Cor、CA水平高于Ta时,但研究组低于对照组,差异有统计学意义(P0.05)。研究组不良反应发生率为6.45%,低于对照组的24.14%,差异有统计学意义(P0.05)。结论:神经刺激仪定位下腰丛联合坐骨神经阻滞应用于下肢手术患者效果较好,患者血液动力学稳定,且应激反应轻,不良反应少。     

超声引导下髂腹下－髂腹股沟神经阻滞应用于男性全身麻醉后导尿管相关膀胱刺激征临床效果的回顾性研究

摘要 目的：探讨超声引导髂腹下－髂腹股沟神经阻滞应用于男性全身麻醉后导尿管相关膀胱刺激征（CRBD）的临床效果。方法：回顾性分析本院收治的60例择期全身麻醉下行下肢清创、皮瓣转移或植皮的男性患者,且术中需留置导尿管者的临床资料。按是否行超声引导下髂腹下－髂腹股沟神经阻滞分为观察组和对照组,观察组在全身麻醉后,超声引导下进行双侧髂腹下-髂腹股沟神经阻滞,神经阻滞完成后行导尿管留置术。对照组麻醉诱导完成后,即行导尿管留置术。记录拔除气管导管后10 min（T1）、1h（T2）、3h（T3）CRBD严重程度评分和Riker镇静-躁动评分。记录术前（T0）和T1、T2、T3对应时点的收缩压（SBP）、舒张压（DBP）、心率（HR）,对比两组的苏醒质量和麻醉相关不良反应。结果：术后各时段观察组CRBD严重程度评分和Riker镇静-躁动评分均明显低于对照组（P＜0.05）;术后各时段观察组的SBP、DBP、HR与对照组相比均明显降低 （P＜0.05）;观察组PACU内非计划性使用镇痛药、非计划性拔除尿管的比例低于对照组,PACU的停留时间短于对照组（P <0.05）;两组麻醉相关不良反应发生率对比未见统计学意义（P >0.05）。结论：超声引导下髂腹下－髂腹股沟神经阻滞操作简便,减轻全身麻醉后CRBD的效果确切,患者对导尿管有良好的耐受,术后血流动力学和循环更稳定,苏醒质量更高。     

超声引导下外周神经阻滞麻醉对老年单膝关节置换术患者血流动力学和认知功能的影响

目的:探究超声引导下外周神经阻滞麻醉对老年单膝关节置换术患者血流动力学和认知功能的影响。方法:选取2017年3月-2019年3月在我院进行单膝关节置换术的老年患者82例,根据麻醉方式不同分为研究组和对照组,每组各41例。研究组采用超声引导下外周神经阻滞麻醉,对照组采用全身麻醉,对比两组的麻醉诱导时间、麻醉维持时间、手术时间等指标,两组入室麻醉前(T0)、气管插管时(T1)、切皮(T2)、止血带60 min(T3)、松止血带5 min(T4)、拔除气管导管时(T5)、术后6 h(T6)、术后24 h(T7)的收缩压(Systolic blood pressure,SBP)、舒张压(Diastolic blood pressure,DBP)、心率(Heart rate,HR)等指标,两组术前、术后6 h、术后12 h、术后24 h的认知功能评分及术后镇痛药物的使用量。结果:研究组的麻醉诱导时间明显长于对照组(P0.05);两组的麻醉维持时间、手术时间比较均无明显差异(P0.05);研究组T1、T3、T5时点HR显著低于对照组(P0.05),T2、T3时点SBP、DBP水平明显高于对照组,T3、T4、T5、T6时点SBP、DBP水平显著低于对照组(P0.05)。两组术前、术后24 h的认知功能评分对比均无统计学差异(P0.05);但研究组术后6 h、术后12 h的认知功能评分均明显高于对照组(P0.05),术后24 h、术后48 h、术后72 h的镇痛药物使用量均明显低于对照组(P0.05)。结论:在老年单膝关节置换术中,超声引导下外周神经阻滞麻醉对患者血流动力学和认知功能的影响较小,且术后镇痛药物使用量更少。     

右美托咪定联合地佐辛在臂丛神经阻滞麻醉中的应用及对血清VEGF、IL-6、IL-10的影响

目的:右美托咪定联合地佐辛在臂丛神经阻滞麻醉中的应用及对血清VEGF(内皮细胞生长因子)、IL-6(白介素-6)、IL-10(白介素-10)的影响。方法:选择我院2016年10月至2017年12月94例上肢骨折内固定术患者作为本次研究对象,随机分为对照组和联合组,各47例。对照组于臂丛阻滞实施前10分钟持续泵注右美托咪定,联合组在此基础上辅助静脉推注地佐辛。随之在超声引导下行肌间沟臂丛神经阻滞对比分析两组患者臂丛神经麻醉前(T0),药物注射分钟后(T1),手术切皮(T2)、手术操作5分钟(T3)、手术操作30分钟(T4)和手术结束(T5)各时间点血流动力学、Ramsay镇静评分、VEGF、IL-6和IL-10水平。结果:联合组T1～T5时间MAP(血压)、HR(心率)均低于对照组(P0.05);两组SpO2(血氧饱和度)在各时间点比较差异无统计学意义(P0.05);联合组T1～T5时间点的Ramsay镇静评分明显优于观察组(P0.05);两组T1～T5时间点VEGF均上升,且联合组各时间点明显高于对照组(P0.05);术后24小时显示,联合组IL-6、IL-10水平显著低于对照组(P0.05);联合组麻醉起效时间明显短于对照组(P0.05),镇痛持续时间、感觉神经和运动神经阻滞的持续时间明显比对照组长(P0.05)。结论:在行上肢手术过程中,联合使用右美托咪定和地佐辛行臂丛神经阻滞麻醉镇痛效果明显,同时可有效刺激VEGF分泌,降低IL-6、IL-10炎症因子水平,加速患者术后恢复。     

右美托咪定对下肢手术使用止血带的血流动力学的影响

目的:观察右美托咪定(dexmedetomidine,Dex)对下肢手术使用止血带的血流动力学的影响.方法:选择择期在我院行下肢手术的患者60例,ASA Ⅰ～Ⅱ级,随机分为2组,即右美托咪定组(dexmedetomidine,D组)和对照组(control,C组),每组30例,两组均选择腰硬联合麻醉.麻醉成功后,D组于上止血带前15 min,用微量泵给予Dex负荷量0.8μg/g,10 min静脉泵入,之后输注速度设定为0.4 μg· kg-1·h-1,直至止血带放气;C组用生理盐水代替右美托咪定,用药方法同D组.记录两组药物给负荷量之前(T0)、止血带充气前(T1)、止血带充气后15 rain(T2)、止血带充气后30 min(T3)、止血带充气后45 min(T4)、止血带充气后60 min(T5)及止血带放气后5 min(T6)的平均动脉压(MAP)、心率(HR)及血氧饱和度(SPO2);记录两组高血流动力学的发生率及所用血管活性药物的量.结果:用药前,两组患者的MAP、HR及SPO2比较,差异均无统计学意义(P＞0.05).D组患者给予负荷量后,T2～T5各时点MAP均较T1显著升高(P＜0.05),而T6时MAP下降,与T1比较无明显差异(P＞0.05);T4～T6各时点HR均较T1显著升高(P＜0.05),各时点SPO2比较均无统计学意义(P＞0.05).C组在T2～T6各时点MAP和HR均较T1显著升高(P＜0.05),各时点SPO2比较均无统计学意义(P＞0.05).T2、T4和T6各时点D组患者的MAP具显著低于C组(P＜0.05),T1～T6各时点HR均显著低于C组(P＜0.05).D组T1时HR显著低于TO时(P＜0.05).C组和D组患者高血流动力学反应的发生率分别为66.7％和20％,C组明显高于D组(P＜0.01).两组患者尼卡地平和阿托品的用量差异均无统计学意义(P＞0.05),但D组麻黄碱的用量明显高于C组(P＜0.05),两组患者均未应用艾司洛尔处理.结论:Dex可减少下肢手术使用止血带时引起的血流动力学高反应的发生.     

七氟醚联合骶管阻滞麻醉对小儿疝气手术的麻醉效果分析

目的:观察七氟醚联合骶管阻滞麻醉对小儿疝气手术的麻醉效果。方法:选取80例行腹股沟疝气手术患儿,按随机数字表法分为两组,对照组(39例)静脉注射氯胺酮,观察组(41例)先吸入8%七氟醚,然后进行骶管阻滞麻醉,通过观察并记录两组患儿生命体征、麻醉诱导时间、苏醒时间、手术麻醉时间、苏醒期躁动评分(Pediatric anesthesia emergence delirium,PAED)和麻醉诱导期合作量表(Induction Compliance Checklist,ICC)及麻醉期间不良反应情况,评价七氟醚联合骶管阻滞麻醉对小儿疝气手术的麻醉效果。结果:两组切皮后T1、T2时心率(HR)、平均动脉压(MAP)水平均高于T0时的值(P0.05),两组切皮后T1、T2时组间HR、MAP水平相比,无统计学差异(P0.05)。两组切皮后T3时HR、MAP水平基本恢复到T0时的水平。两组切皮前后4个时间点的血氧饱和度(Sp O2)相比,无统计学差异(P0.05)。观察组患儿麻醉诱导时间,苏醒时间均明显短于对照组患儿(P0.05),两组术中麻醉持续时间相比,无统计学差异(P0.05),均能达到期望麻醉时间,观察组患儿PAED评分和ICC评分均低于对照组患儿(P0.05),不良反应组间比较无统计学差异(P0.05)。结论:七氟醚联合骶管阻滞麻醉对小儿疝气手术具有良好的麻醉效果,麻醉诱导快,苏醒快,小儿配合度高,术后躁动少,值得临床推广使用。     

超声引导下外周神经阻滞对老年下肢动脉硬化闭塞症截肢术患者循环系统和疼痛的影响

目的:研究超声引导下外周神经阻滞对老年下肢动脉硬化闭塞症截肢术患者循环系统和疼痛的影响。方法:选择我院2016年2月～2019年11月收治的82例老年下肢动脉硬化闭塞症患者为研究对象,所有患者均接受下肢截肢术治疗,对照组采用硬膜外麻醉,研究组采用超声引导下外周神经阻滞。对比两组感觉神经、运动神经阻滞情况、阻滞效果,循环功能,疼痛指标和不良反应。结果:研究组感觉神经及运动神经阻滞起效时间较对照组短,感觉神经及运动神经阻滞维持时间较对照组长,差异比较有统计学意义(P0.05)。两组优良率差异比较无统计学意义(P0.05)。手术开始30 min时,对照组心率、平均动脉压均下降,研究组无明显改变,差异比较有统计学意义(P0.05)。术后24h时,两组疼痛指标浓度均较入室时增加,研究组低于对照组,差异比较有统计学意义(P0.05)。研究组不良反应总发生率低于对照组(P0.05)。结论:老年下肢动脉硬化闭塞症截肢术患者予以超声引导下外周神经阻滞的起效时间更快,能够减轻围术期疼痛,保持术中循环功能的稳定。     

右美托咪定经鼻滴注对脊柱手术患者围术期血流动力学变化及镇静作用的临床研究

目的:观察右美托咪定经鼻滴注对脊柱手术患者围术期的镇静作用及对血流动力学变化的影响。方法:将90名ASAⅠ~Ⅲ级、18~65岁、拟在全身麻醉下行脊柱手术、且术后须拔除气管导管的患者,随机分为三组:对照组(C组)、右美托咪定1μg/kg组(D1组)和右美托咪定1.5μg/kg组(D2组),n=30。分别记录给药前(T0)、诱导前(T1)、插管前1 min(T2)、插管后1 min(T3)、手术开始即刻(T4)、术毕停全麻药时(T5)、拔管前1 min(T6)、拔管后3 min(T7)和入PACU(T8)时患者的心率(HR)、平均动脉压(MAP)、氧饱和度(SPO_2),术毕停全麻药至拔除气管导管的时间、患者在术后恢复室停留时间、Ramsay镇静评分。结果:T0时3组患者HR、MAP、SPO_2、Ramsay镇静评分无统计学差异(P≥0.05);与C组相比,D1组和D2组各时间点HR、MAP明显降低,Ramsay镇静评分提高(P≤0.05),SPO_2无明显变化(P≥0.05);与D1组相比,D2组各时间点HR、MAP明显降低、Ramsay镇静评分提高(P≤0.05),SPO_2无明显变化(P≥0.05);D1组各时间点HR、MAP、SPO_2、Ramsay镇静评分无明显差异(P≥0.05);D2组HR、MAP、SPO_2、Ramsay镇静评分明显无差异(P≥0.05)。C组T3、T4、T5、T6、T7、T8各时间点HR、MAP均较T1、T2升高,Ramsay镇静评分均明显提高(P≤0.05),SPO_2无明显变化(P≥0.05)。结论:麻醉诱导前40 min右美托咪定经鼻滴注可有效抑制插管和拔管期反应、使血流动力学变化更加稳定,并显著降低降低患者术后躁动的发生率。     

肝功能障碍患者对罗库溴铵药效动力学的影响

目的:探讨不同肝功能分级患者对肌松药罗库溴铵药效动力学的影响。方法:纳入肝功能障碍的手术患者152例,根据肝功能Child-Pugh分级将其分为Child-Pugh A级组62例、Child-Pugh B级组55例、Child-Pugh C级组35例,同时纳入肝功能正常患者60例为对照组。以维库溴铵以动态靶控输注程序控制,0.15~0.2μg/m L之间,维持肌松水平T1/TC在25%以内。对比分析四组间一般情况(包括性别、年龄、体重和BMI指数)、麻醉起效时间、最大阻滞持续时间、T110%恢复时间、T125%恢复时间、T175%恢复时间、恢复指数。结果:Child-Pugh A、B、C组患者的麻醉起效时间逐渐延长,组间差异有统计学意义(P0.05)。Child-Pugh A、B、C三组间患者的麻醉最大阻滞程度逐渐下降,组间差异有统计学意义(P0.05)。Child-Pugh A、B、C三组间患者的麻醉恢复指数逐渐增大,组间差异有统计学意义(P0.05)。Child-Pugh A、B、C和对照组间T110%恢复时间、T125%恢复时间、T175%恢复时间无明显差异(P0.05)。Child-Pugh A级组女性麻醉起效时间明显快于男性,差异有统计学意义(P0.05);男性最大阻滞持续时间小于女性,性别间差异有统计学意义(P0.05)。肝功能Child-Pugh B级组女性麻醉起效时间明显快于男性,差异有统计学意义(P0.05)。肝功能Child-Pugh C级组性别间麻醉起效时间、最大阻滞持续时间、恢复指数差异无统计学意义(P0.05)。结论:肝功能障碍明显影响肌松药罗库溴铵麻醉起效时间,重度肝功能患者使用罗库溴铵时可不考虑性别的影响因素。     

右美托咪定与丙泊酚用于臂丛神经阻滞下上肢骨折患者术中镇静作用的比较

目的探讨右美托咪定与丙泊酚对臂丛神经阻滞下上肢骨折手术患者的镇静效果差异。方法将2015年9月至2015年12月我院80例择期上肢骨折手术患者随机均分为右美托咪定(D组)与丙泊酚(P组),分别记录两组患者给药前(T0)、切皮前即用药后15min(T1)、手术开始后30min(T2)及术毕(T3)MAP、HR、Ramsay镇静评分等情况,对数据进行统计学分析。结果 T1~T3时D组MAP明显低于To时和P组,Ramsay镇静评分低于P组,HR慢于To时和P组(P0.05)。结论右美托咪定用于臂丛神经阻滞下上肢骨折手术患者镇静是安全和可行的,镇静效果好于丙泊酚,且血流动力学稳定。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势, 我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加, 取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展; 中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势, 若干领域已从“追赶”状态跨越到“领跑”地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述, 旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点, 展示中国科学家所取得的杰出成就。     

2017年中国植物科学若干领域重要研究进展

2017年中国植物科学继续保持高速发展态势, 重大成果频出, 具体表现在中国植物学家在国际顶级学术期刊发表的文章数量平稳上升。中国植物科学领域的研究工作者成果精彩纷呈, 如新型广谱抗病机制的发现、水稻广谱抗病遗传基础及机制和疫霉菌诱发病害成灾机制研究等。2017年中国生命科学领域十大进展评选中, 有两项植物科学领域的研究成果入选。水稻生物学、进化与基因组学和激素生物学等领域学科发展突出。另外, 值得一提的是, 长期从事高等植物与代谢途径调控分子网络研究和水稻品种设计育种的李家洋院士的研究成果“水稻高产优质性状形成的分子机理及品种设计”荣获2017年国家自然科学一等奖。这一具有重大国际影响的开创性贡献标志着中国植物科学在该领域的国际科学前沿居于引领和卓越地位。该文对2017年中国本土科学家在植物科学若干领域取得的重要研究成果进行了系统梳理, 旨在全面追踪和报道当前中国植物科学领域发展的最新前沿动态, 与广大读者共同分享我国科学家所取得的辉煌成就。     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义。综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望。     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.     

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势, 我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加, 取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展; 中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势, 若干领域已从“追赶”状态跨越到“领跑”地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述, 旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点, 展示中国科学家所取得的杰出成就。     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义.综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望.     

Apoptosis in experimental myocardial infarction in situ and in the perfused heart in vitro

We report the appearance of apoptotic cells in experimental myocardial infarction (rabbit heart) in in situ and in vitro preparations. Apoptosis was recognized by intravital staining with Hoechst 33342 (Ho342), by nick-end labeling (TUNEL) and by DNA laddering. A steady rise in the relative number of apoptotic cardiomyocytes (apoptotic index) was noted in in situ preparations. Apoptosis was first noted 6 h after the onset of ischemia with its highest value occurring after 72 h. Apoptotic nuclei were absent in remote areas of the left and right ventricles. Apoptotic nuclei within the infarcted area showed diminished intensity of Ho342 fluorescence. Three days after ischemia, a border zone adjacent to the infarcted area consisting of apoptotic macrophages was recognized. A novel finding was the appearance of apoptotic cardiomyocytes in the isolated perfused ischemic heart. Occurring as early as 50 min after the onset of ischemia, a high apoptotic index was present adjacent to the ligature placed around the coronary artery. This observation provides the opportunity to selectively examine factors leading to apoptosis in the ischemic heart under controlled experimental conditions.     

Changes in aquatic vegetation in Rhine floodplain streams in Alsace in relation to disturbance

Abstract. Changes are described in aquatic vegetation in oligotrophic, groundwater-fed Rhine floodplain streams in Alsace (eastern France), resulting from disturbance. Disturbance factors include changes in nutrients, either permanent ones - effluent from a waste water treatment plant or trout hatcheries - or periodic ones: flooding. Regular inputs of high levels of phosphate and ammonia modified the macrophyte vegetation in these streams. The floristic composition, which was characteristic of oligotrophic waters upstream of the eutrophicated sector, changed to that of a eutrophic situation as originally found downstream. Periodic disturbance by floods which normally occur once a year, irregularly eutrophicates the small streams, causing the development of a mixture of eutrophic and oligotrophic species. Six macrophyte communities are distinguished, indicating different trophic levels. The aquatic vegetation is adapted to the variations of phosphate and ammonia levels. Hence, aquatic macrophytes can be used as bio-indicators of fluctuations in water nutrient levels in relation to the type of disturbance.     

Morphine-potentiated platelet aggregation in in vitro and platelet plug formation in in vivo experiments

The detailed mechanisms underlying morphine-signaling pathways in platelets remain obscure. Therefore, we systematically examined the influence of morphine on washed human platelets. In this study, washed human platelet suspensions were used for in vitro studies. Furthermore, platelet thrombus formation induced by irradiation of mesenteric venules with filtered light in mice pretreated with fluorescein sodium was used for an in vivo thrombotic study. Morphine concentration dependently (0.6, 1, and 5 microM) potentiated platelet aggregation and the ATP release reaction stimulated by agonists (i.e., collagen and U46619) in washed human platelets. Yohimbine (0.1 microM), a specific alpha(2)-adrenoceptor antagonist, markedly abolished the potentiation of morphine in platelet aggregation stimulated by agonists. Morphine also potentiated phosphoinositide breakdown and intracellular Ca(2+) mobilization in human platelets stimulated by collagen (1 microg/ml). Moreover, morphine (0.6-5 microM) markedly inhibited prostaglandin E(1) (10 microM)-induced cyclic AMP formation in human platelets, while yohimbine (0.1 microM) significantly reversed the inhibition of cyclic AMP by morphine (0.6 and 1 microM) in this study. The thrombin-evoked increase in pH(i) was markedly potentiated in the presence of morphine (1 and 5 microM). Morphine (2 and 5 mg/g) significantly shortened the time require to induce platelet plug formation in mesenteric venules. We concluded that morphine may exert its potentiation in platelet aggregation by binding to alpha(2)-adrenoceptors in human platelets, with a resulting inhibition of adenylate cyclase, thereby reducing intracellular cyclic AMP formation followed by increased activation of phospholipase C and the Na(+)/H(+) exchanger. This leads to increased intracellular Ca(2+) mobilization, and finally potentiation of platelet aggregation and of the ATP release reaction.