血栓通预处理对大鼠心肌缺血再灌注损伤的影响

目的:研究血栓通对大鼠缺血心肌的保护作用。方法:选用40只Wister大鼠分为正常对照组、模型组、血栓通组及维拉帕米组,采用结扎大鼠冠状动脉左前降支建立出大鼠心肌缺血再灌注损伤模型。检测大鼠血清磷酸肌酸激酶(CPK)、乳酸脱氢酶(LDH)、血清及心肌组织超氧化物歧化酶(SOD)和脂质过氧化物丙二醛(MDA),研究血栓通对心肌梗死范围的影响。结果:血栓通可对抗结扎大鼠冠状动脉左前降支所致的大鼠急性心肌损伤,使心肌缺血大鼠的CPK及LDH降低,并可增加心肌组织SOD的活性,减少MDA生成且能显著缩小心肌梗死的范围。结论:血栓通对大鼠心肌缺血有保护作用,其机制可能与抗脂质过氧化反应有关。     

原花青素对大鼠心肌缺血再灌注损伤的保护作用

目的：观察原花青素（procyanidin,PC）对大鼠心肌缺血再灌注损伤的保护作用，方法：结扎大鼠冠状动脉左前降支（LAD）40min，复灌120min后复制出大鼠心肌缺血再灌注损伤模型，观察PC对大鼠心肌酶学，心梗面积和脂质过氧化的影响。结果：PC能减少心肌细胞磷酸肌酶激酶（CPK）和乳酸脱氢酶（LDH）的释放，明显缩小心肌梗死面积，能显提高大鼠血清和心肌组织中超氧化物歧化酶（SOD）活性，降低心肌和血清脂质过氧化代谢产物丙二醛（MDA）含量，结论：PC对大鼠心肌缺血再灌注损伤有保护作用，其机制可能与清除自由基，抑制脂质过氧化反应有关。     

玉郎伞提取物对大鼠心肌缺血再灌注损伤的保护作用

目的:研究玉郎伞(YLS)对心肌缺血再灌注损伤(MIRI)的影响.方法:以Wistar大鼠制备MIRI模型(结扎冠状动脉5 min后再灌注30 min),观察YLS对心肌梗死面积及心肌组织丙二醛(MDA)含量、超氧化物歧化酶(SOD)活力及血清中乳酸脱氢酶(LDH)、肌酸磷酸激酶(CK)活性生化指标的影响.结果:YLS明显降低心肌梗死范围、提高心肌组织中SOD活力、降低其MDA含量,同时降低血清中CK和LDH活力(P<0.01或P<0.05).结论:YLS对大鼠心肌缺血再灌注损伤具有显著的保护作用.     

川芎嗪对大鼠心肌缺血再灌注损伤保护作用的研究

目的观察川芎嗪对心肌缺血再灌注损伤的保护作用及机理。方法采用大鼠冠脉结扎30min后再通20min造成心肌缺血再灌模型。大鼠随机分对照组、缺血组、模型组(缺血再灌组)和川芎嗪保护组。观测心肌细胞膜和线粒体中过氧化物歧化酶(SOD)、还原型谷胱甘肽(GSH·PX)、Ca2 _ATP酶和K ,Na _ATP酶活力 ,MDA及心肌钙含量。结果川芎嗪保护组心肌细胞膜SOD、GSH·PX、Ca2 _ATP酶和Na ,K _ATP酶活性较缺血再灌组均有显著性升高(P<0.05或P<0.01) ,丙二醛(MDA)和心肌钙含量却呈显著性降低。线粒体中SOD和GSH·PX活力也呈显著性升高(P<0.05),MDA却为显著性降低。结论川芎嗪对大鼠缺血再灌注损伤心肌有确切保护作用 ,其机理是通过提高对氧自由基的清除及抑制脂质过氧化。     

重组人骨形态发生蛋白-7对大鼠心肌缺血再灌注损伤的影响

为探讨重组人骨形态发生蛋白-7(rhBMP-7)对大鼠心肌缺血再灌注损伤的保护作用,建立Wist-ar大鼠心肌缺血再灌注模型。随机分为对照组(C组)、缺血再灌注组(I组)和rhBMP-7处理组(B组),每组10只。B组于血流阻断前10min股静脉给予rhBMP-7250μg/kg,C组和I组给予等量生理盐水。于血流再灌注后24h取血检测乳酸脱氢酶(LDH)和磷酸肌酸激酶(CPK)含量;心肌匀浆检测丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性;电镜下观察心肌组织学变化。结果表明,rhBMP-7处理组大鼠心肌缺血再灌注24h后,其心肌酶含量和MDA均明显低于I组,SOD活性增加(P<0·01);心肌细胞的坏死程度也明显轻于I组。结论:rhBMP-7降低心肌脂质过氧化,增强心肌抗氧化酶活力,对心肌缺血再灌注损伤具有保护作用。     

红花黄素对大鼠心肌缺血-再灌注模型的作用及机制研究

目的　研究红花黄素对心肌缺血 -再灌注大鼠的影响。方法　建立大鼠冠脉结扎致心肌缺血 -再灌注损伤模型 ,观察红花黄素预防性给药对缺血大鼠血浆中肌酸磷酸激酶 (CPK)、乳酸脱氢酶 (LDH)活性及心肌和血浆中脂质过氧化物丙二醛 (MDA)含量 ,超氧化物歧化酶 (SOD)活性的影响。结果　红花黄素预防性给药能明显降低血浆CPK、LDH的活性及MDA含量 ,提高SOD的活性 ,具有明显的抗氧化性。结论　红花黄素对实验性心肌缺血 -再灌注大鼠具有明显的保护作用 ,其作用可能与其抗氧化有关     

褪黑素对大鼠心肌缺血/再灌注损伤的影响

通过褪黑素（MT）对大鼠心肌缺血／再灌注损伤（IRI）的影响的研究。证实了MT能抗心肌缺血／再灌注损伤，并探讨其作用机制。实验采用在体大鼠心肌缺血再灌注损伤的模型，观察了MT对此模型大鼠缺血期、再灌注期心律失常发生的抑制作用及再灌注结束后心肌超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量及血浆乳酸脱氢酶（LDH）、肌酸激酶（CK）活性的影响，同时用酶组织化学染色法观察琥珀酸脱氢酶（SDH）的改变。结果：表明MT能明显降低缺血和再灌注后室速（VT）和室颤（VF）的发生率，显著缩短其持续时间，明显提高心肌SOD活性，显著减少MDA含量，减少血浆LDH，CK的含量，明显减轻SDH损伤性反应，从而证实它对心肌的保护作用与增强机体内源性抗氧化能力，清除氧自由基，减少脂质过氧化以及保护线粒体有关。     

羟丁酸钠对离体大鼠缺血再灌注损伤心肌的影响

目的比较不同剂量羟丁酸钠对离体大鼠缺血再灌注损伤心肌脂质过氧化作用的影响。方法将24只成年Wistar大鼠随机分为4组(n=6):心肌缺血再灌注组(I/R组),1 mmol/L羟丁酸钠组(RL组),2.5 mmol/L羟丁酸钠组(RM组),10 mmol/L羟丁酸钠组(RH组)。采用Langendorff离体心脏缺血再灌注模型,四组均以K-H液平衡灌注10 min,再以K-H液及1、2.5、10 mmol/L羟丁酸钠的K-H液分别灌注10 min,然后全心停止灌注25 min,再分别继续灌注30 min。测定冠脉流出液总乳酸脱氢酶(LDH)活性;灌注末,用2.5%戊二醛固定左室心肌组织,观察心肌超微结构;留取心尖部心肌组织以检测8-异前列腺素、超氧化物歧化酶(SOD)活性。结果与IR组比较,RL组8-异前列腺素含量、SOD及LDH活性差异均无统计学意义(P>0.05),超微结构也未见损伤减轻;RM组8-异前列腺素含量、SOD活性差异均无统计学意义(P>0.05),LDH活性差异有统计学意义(P<0.05),超微结构可见损伤减轻;RH组8-异前列腺素含量、LDH活性升高(P<0.05),SOD活性差异均无统计学意义(P>0.05),超微结构可见损伤加重。结论羟丁酸钠(1、2.5 mmol/L)不能降低心肌缺血再灌注损伤大鼠的8-异前列腺素含量,抑制脂质过氧化反应;但是2.5 mmol/L羟丁酸钠能减轻大鼠心肌缺血再灌注损伤;10 mmol/L羟丁酸钠则加重了脂质过氧化反应和心肌缺血再灌注损伤。     

异丙酚对缺血再灌注损伤大鼠海马线粒体能量代谢、ATP酶活性及自由基系统的影响

目的：观察异丙酚对缺血再灌注损伤大鼠海马线粒体能量代谢、ATP酶活性、脂质过氧化及超微结构的影响。方法：雄性Wistar大鼠30只，随机分为假手术组、缺血再灌注对照组和缺血再灌注异丙酚处理组。采用大鼠全脑缺血再灌注损伤模型。全脑缺血10min再灌注60min时，断头处死大鼠。检测海马线粒体三磷酸腺苷(ATP)、丙二醛(MDA)含量及Na^ -K^ -ATP酶、Ca^2 -ATP酶、超氧化物歧化酶(SOD)、谷胱甘肽(GSH)活性并观察线粒体超微结构的改变。结果：缺血再灌注后海马线粒体的ATP含量及Na^ -K^ -ATP酶、Ca^2 -ATP酶、SOD、GSH活性均有不同程度的降低，MDA含量增高，线粒体超微结构亦发生明显损害；麻醉相关剂量的异丙酚可使ATP含量、Na^ -K^ -ATP酶、Ca^2 -ATP酶、SOD、GSH活性有不同程度的恢复，并降低MDA的含量，减轻线粒体损伤的程度。结论：异丙酚对脑缺血再灌注损伤的保护作用可能与其抑制线粒体脂质过氧化反应，清除自由基，保持线粒体结构的完整性，促进线粒体ATP含量和ATP酶活性的恢复有关。     

川芎嗪与阿魏酸配伍对大鼠心肌缺血再灌注损伤心肌的保护作用

目的:观察川芎嗪与阿魏酸配伍对大鼠心肌缺血再灌注损伤的保护作用。方法:将健康雄性SD大鼠64只,随机分为4组,每组16只。分别为正常组、假手术组、模型组及川芎嗪与阿魏酸配伍组。后2组制备大鼠急性心肌缺血再灌注损伤模型。造模6h后检测血清肌酸磷酸激酶(CK)、乳酸脱氢酶(LDH)、心肌超氧化物歧化酶(SOD)、丙二醛(MDA);24h后取心脏,RT-PCR法检测细胞间黏附分子(ICAM-1)、P-选择素、E-选择素mRNA表达。结果:川芎嗪与阿魏酸配伍可明显降低心肌缺血再灌注损伤大鼠血清CK(P<0.01);但对血清LDH以及心肌SOD和MDA作用不明显(P>0.05);还可显著降低E-选择素、P-选择素mRNA表达(P<0.01)。结论:川芎嗪与阿魏酸配伍对大鼠心肌缺血再灌注损伤心肌有明显的保护作用。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

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.

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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.

     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

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.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

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.     

2-(Acetoxyphenyl)-(Z)-styryl sulfides as cyclooxygenase inhibitors

2-(Acetoxyphenyl)-(Z)-styryl sulfides are described as selective cyclooxygenase-2 (COX-2) inhibitors, useful for treating inflammation and COX-2-mediated disorders including neoplasia. 2-(Acetoxyphenyl)-(Z)-styryl sulfide is claimed to be the most potent COX inhibitor in the series with a COX-2 selectivity ratio of 33. This compound is also claimed to be superior to celecoxib (Celebrex^®, Pfizer) in inhibiting cell growth of colorectal carcinoma cells. In this evaluation, the COX inhibitory activity of this compound is compared to that previously disclosed for diarylheterocycles and 2-(acetoxyphenyl)alkyl sulfides. The validity of the DLD-1 cell line in the growth inhibition studies is questioned based on recent literature reports indicating the lack of COX-2 expression in this cell line.     

Sleep-disordered breathing with chronic opioid use

Chronic opioid use for pain relief or as substitution therapy for illicit drug abuse is prevalent in our societies. In the US, retail distribution of methadone and oxycodone has increased by 824 and 660%, respectively, between 1997 and 2003. μ-Opioids depress respiration and deaths related to illicit and non illicit chronic opioid use are not uncommon. Since 2001 there has been an emerging literature that suggests that chronic opioid use is related to central sleep apnoea of both periodic and non-periodic breathing types, and occurs in ～ 30% of these subjects. The clinical significance of these sleep-related abnormalities are unknown. This review addresses the present knowledge of control of ventilation mechanisms during wakefulness and sleep, the effects of opioids on ventilatory control mechanisms, the sleep-disordered breathing found with chronic opioid use and a discussion regarding the future research directions in this area.     

Drug targets for cognitive enhancement in neuropsychiatric disorders

The investigation of novel drug targets for treating cognitive impairments associated with neurological and psychiatric disorders remains a primary focus of study in central nervous system (CNS) research. Many promising new therapies are progressing through preclinical and clinical development, and offer the potential of improved treatment options for neurodegenerative diseases such as Alzheimer's disease (AD) as well as other disorders that have not been particularly well treated to date like the cognitive impairments associated with schizophrenia (CIAS). Among targets under investigation, cholinergic receptors have received much attention with several nicotinic agonists (α7 and α4β2) actively in clinical trials for the treatment of AD, CIAS and attention deficit hyperactivity disorder (ADHD). Both glutamatergic and serotonergic (5-HT) agonists and antagonists have profound effects on neurotransmission and improve cognitive function in preclinical experiments with animals; some of these compounds are now in proof-of-concept studies in humans. Several histamine H3 receptor antagonists are in clinical development not only for cognitive enhancement, but also for the treatment of narcolepsy and cognitive deficits due to sleep deprivation because of their expression in brain sleep centers. Compounds that dampen inhibitory tone (e.g., GABA_A α5 inverse agonists) or elevate excitatory tone (e.g., glycine transporter inhibitors) offer novel approaches for treating diseases such as schizophrenia, AD and Down syndrome. In addition to cell surface receptors, intracellular drug targets such as the phosphodiesterases (PDEs) are known to impact signaling pathways that affect long-term memory formation and working memory. Overall, there is a genuine need to treat cognitive deficits associated with many neuropsychiatric conditions as well as an increasingly aging population.