大蒜素对白血病细胞增殖和凋亡的影响

目的通过观察中药大蒜素(allicin)对人髓系白血病细胞株HL-60增殖、凋亡及bcl-2mRNA表达的影响,探讨大蒜素的作用机制。方法采用MTT法绘制细胞生长曲线;TdT酶介导的原位缺口末端标记法(TUNEL)分析凋亡细胞;RT-PCR法检测大蒜素作用后不同时间段bcl-2mRNA表达水平的变化。结果大蒜素对HL-60细胞增殖具有明显的抑制作用,呈时间和浓度依赖性,并能抑制HL-60细胞集落形成。较低浓度大蒜素即可抑制HL-60细胞增殖。作用24hTUNEL法检测到凋亡细胞;细胞凋亡率呈药物浓度依赖性且使bcl-2/bax下调。大蒜素作用HL-60细胞后,bcl-2mRNA表达水平有不同程度下调,并呈剂量依赖性。结论大蒜素能够有效抑制HL-60细胞增殖,并诱导其凋亡;bcl-2表达水平下调可能参与了该过程。     

菊苣酸诱导人白血病细胞HL-60凋亡作用及机制研究

目的观察菊苣酸诱导人急性髓系白血病细胞株HL-60凋亡的作用并初步探讨其机制。方法培养HL-60细胞,分别给予终浓度为10¹00μmol·L-1的菊苣酸48 h,检测细胞活性和凋亡、Caspase-3活性以及Bcl-2蛋白表达水平。结果终浓度为10100μmol·L-1的菊苣酸48 h,检测细胞活性和凋亡、Caspase-3活性以及Bcl-2蛋白表达水平。结果终浓度为10¹00μmol·L-1的菊苣酸能呈浓度依赖性降低HL-60细胞增殖活性和增加凋亡,增强Caspase-3活性和下调Bcl-2蛋白表达。结论菊苣酸具有抑制白血病细胞株HL-60增殖活性和诱导其凋亡作用,其机制与降低抗凋亡蛋白Bcl-2表达及增强Caspase-3活性有关。     

雷公藤内酯醇体内外对HL-60细胞作用的研究

目的探讨雷公藤内酯醇(triptolide,TPL)在体内外对人髓系白血病细胞株HL-60的作用。方法运用MTT比色法检测TPL对HL-60细胞的增殖抑制作用,采用TdT酶介导的缺口末端标记法(TUNEL)检测TPL对HL-60细胞的诱导凋亡作用;建立HL-60裸鼠异种移植瘤模型,观察经TPL治疗后的肿瘤抑制率。结果在体外,TPL对HL-60细胞的增殖具有明显的抑制及诱导凋亡作用,呈时间和剂量依赖性;在体内,TPL可抑制HL-60细胞裸鼠异种移植瘤生长,抑制率最高可达53.5%。结论TPL在体内外均可抑制HL-60细胞增殖,并诱导其凋亡。     

生存素在VP16诱导HL-60白血病细胞凋亡中的作用

目的探讨生存素在化疗药物足叶乙甙（VP16）诱导白血病细胞凋亡中的作用。方法用HL-60白血病细胞株进行传代培养,MTT试验检测VP16不同药物浓度对白血病细胞增殖的影响。通过光镜下观察细胞形态学变化和DNA凝胶电泳定性检测细胞凋亡,用流式细胞术（FCM）定量检测细胞凋亡及周期变化,用RT-PCR检测生存素基因表达,免疫组化检测其蛋白表达。结果各种浓度的VP16均可诱导HL-60细胞凋亡,下调生存素表达,阻滞细胞周期,具有明显时间和浓度依赖性。结论VP16诱导白血病细胞凋亡可能与其抑制生存素表达有关。     

三丁酸甘油酯对白血病细胞株HL-60体外作用的研究

目的探讨三丁酸甘油酯(TB)对白血病细胞株HL-60细胞增殖的抑制作用,并对其作用机制进行初步探讨。方法采用MTT法观察细胞增殖变化。应用免疫组化检测抑癌基因P16的表达。应用流式细胞仪观察细胞周期的改变。通过DNA电泳观察细胞凋亡。结果TB可以抑制细胞增殖。1.0 mmol/L的TB作用72 h,有典型的DNA梯形条带。细胞周期阻滞在G0/G1期。结论TB能抑制HL-60细胞增殖,诱导细胞凋亡,其机制可能与上调P16表达有关。     

熊果酸对HL-60细胞株凋亡及Bcl-2和bax表达的影响

目的探讨熊果酸(UA)抑制人急性髓性白血病细胞系(HL-60)细胞增殖和诱导凋亡作用,并观察Bcl-2和bax基因表达的影响。方法体外培养HL-60细胞。MTT比色法检测增殖活性;流式细胞术(FCM)检测细胞凋亡和细胞周期分布;Western Blot分析Bcl-2和bax基因表达。结果 UA显著抑制HL-60细胞增殖,呈浓度依赖性;UA呈浓度依赖性诱导HL-60细胞凋亡,明显阻滞于细胞周期G1期;UA以浓度依赖方式下调Bcl-2蛋白表达和上调bax蛋白表达。结论 UA抑制HL-60细胞增殖和诱导凋亡,其作用机制与下调Bcl-2上调bax蛋白表达相关。     

人参皂甙Rg1诱导HL-60细胞凋亡的初步研究

目的探讨人参皂甙Rg1对急性早幼粒细胞性白血病细胞HL-60的增殖抑制作用以及对细胞周期和凋亡的影响。方法采用MTT法测定药物对细胞的抑制率,通过细胞形态学观察细胞分裂及凋亡,应用流式细胞仪进行细胞周期分析。结果人参皂甙Rg1呈剂量依赖性抑制HL-60细胞增殖,48 h后抑制50%细胞生长的药物浓度(IC50)为85μg±25μg。流式细胞仪分析结果显示25~400μg/m l人参皂甙Rg1作用于HL-60细胞24-72 h后,呈剂量依赖性的将细胞阻滞于G1期,使G1期不能运行到S期,从而影响了肿瘤细胞的有丝分裂,并且在低于G0/G1期出现典型的凋亡峰。细胞形态学观察可见分裂细胞以及凋亡细胞。结论人参皂甙Rg1能够抑制急性早幼粒白血病细胞HL-60细胞的增殖,诱导G1期阻滞及细胞凋亡。     

人参皂甙Rg1诱导HL-60细胞凋亡的初步研究

目的探讨人参皂甙Rg1对急性早幼粒细胞性白血病细胞HL-60的增殖抑制作用以及对细胞周期和凋亡的影响.方法采用MTT法测定药物对细胞的抑制率,通过细胞形态学观察细胞分裂及凋亡,应用流式细胞仪进行细胞周期分析.结果人参皂甙Rg1呈剂量依赖性抑制HL-60细胞增殖,48 h后抑制50%细胞生长的药物浓度(IC50)为85 μg±25 μg.流式细胞仪分析结果显示25～400 μg /ml人参皂甙Rg1作用于HL-60细胞24-72 h后,呈剂量依赖性的将细胞阻滞于G1期,使G1期不能运行到S期,从而影响了肿瘤细胞的有丝分裂, 并且在低于G0/G1期出现典型的凋亡峰.细胞形态学观察可见分裂细胞以及凋亡细胞.结论人参皂甙Rg1能够抑制急性早幼粒白血病细胞HL-60细胞的增殖,诱导G1期阻滞及细胞凋亡.     

柑橘提取物诺必擂停对K562、HL-60细胞株增殖抑制作用

目的观察柑橘提取物诺必擂停对白血病细胞株K562、HL-60增殖的抑制作用。方法采用MTT法检测诺必擂停对细胞增殖的抑制率,电镜下观察细胞的形态变化。结果诺必擂停对白血病细胞株K562、HL-60的增殖有显著的抑制作用。电镜下可见细胞凋亡的形态学表现。结论柑橘提取物诺必擂停能够明显抑制白血病细胞株K562、HL-60的体外增殖,其机制与诱导K562、HL-60的凋亡有关。     

槲皮素诱导人白血病HL-60细胞凋亡(英文)

目的:研究槲皮素是否能诱导人白血病HL-60细胞凋亡.方法:应用琼脂糖凝胶电泳法观察DNA碎片;采用流式细胞仪检测DNA断裂;电镜技术观察凋亡的形态学改变,用MTT测定法测定细胞增殖.结果:槲皮素15-120 μmol·L~(-1)诱导HL-60细胞凋亡,电镜观察到典型的形态学改变,电泳显示梯状条带,槲皮素能剂量依赖性地触发DNA降解及抑制细胞增生(IG_(50)和95％可信区间分别为43(30-61)μmol·L~(-1).结论:槲皮素诱导人白血病HL-60细胞凋亡.     

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.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

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.     

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.     

Steroidal sapogenin contents in some domestic plants

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.