异喹啉类的新化合物CPUC1对K562/A02细胞多药耐药的逆转作用

目的　研究新化合物CPUC1对K5 6 2 /A0 2细胞多药耐药的逆转作用。方法　MTT法检测长春新碱细胞毒作用。流式细胞仪测定细胞内罗丹明 12 3的累积。DNA含量分析和AnnexinV/PI双染测定长春新碱诱导的细胞凋亡作用。结果　CPUC1可以明显逆转K5 6 2 /A0 2细胞对长春新碱的耐药性。CPUC1可以浓度依赖性增加K5 6 2 /A0 2细胞内罗丹明12 3的积累。CPUC1可明显增强长春新碱诱导的K5 6 2 /A0 2细胞凋亡。结论　CPUC1通过抑制P 糖蛋白 (P glycoprotein ,P gp)功能逆转了P gp介导的K5 6 2 /A0 2细胞的多药耐药性     

槲皮素体外逆转白血病细胞耐药性的研究

目的 :探讨槲皮素对白血病细胞多药耐药逆转的影响。方法 :以人白血病细胞系K5 62及耐药细胞系K5 62 A0 2 (耐阿霉素 )为实验对象 ,采用MTT法检测细胞毒性 ,流式细胞仪检测P gp表达水平。结果 :1 0 μmol·L- 1 槲皮素对细胞毒性和P gp的表达无影响 ,2 0、40 μmol·L- 1 槲皮素能明显增强化疗药物对细胞的毒性 ,降低P gp表达的水平。结论 :槲皮素能逆转K5 62 A0 2细胞耐药性     

补骨脂素逆转多药耐药细胞系K562/ADR耐药性研究

目的　研究补骨脂素对白血病细胞阿霉素耐药株(K5 6 2 /ADR)多药耐药 (multidrugresistance,MDR)性的逆转作用及其机制。方法　采用MTT法检测药物细胞毒性作用 ,高效液相色谱法检测细胞内阿霉素 (ADR)的浓度 ,流式细胞术测定细胞P 糖蛋白 (P gp)的表达。 结果　补骨脂素 (1～ 2 0 μmol·L-1)能不同程度地降低ADR对K5 6 2 /ADR细胞的IC50 。 2 0 μmol·L-1能显著提高ADR在K5 6 2 /ADR细胞内的浓度 ,降低K5 6 2 /ADR细胞P gp的表达。 结论　补骨脂素能逆转K5 6 2 /ADR细胞的MDR ,其机制与抑制P gp的功能及其表达 ,增加细胞内ADR的积累有关     

一种新四氢异喹啉类化合物H108体外抑制P-糖蛋白功能及对PC12细胞损伤的保护作用

目的 :观察新合成四氢异喹啉衍生物H10 8抑制P 糖蛋白 (P gp)功能及对PC12细胞损伤的保护作用。方法 :测定H10 8对K5 6 2 ADR细胞株及大鼠脑微血管内皮细胞 (RBMECs)内罗丹明 12 3(Rh12 3)积聚的影响 ,考察H10 8逆转P gp介导的多药耐药性及对血脑屏障上P gp药物外排功能的影响。以连二亚硫酸钠 (Na2 S2 O4)建立缺血缺氧损伤模型 ,过氧化氢 (H2 O2 )建立氧化应激损伤模型 ,硝普钠 (SNP)建立NO损伤模型 ,MTT法测定H10 8对三种PC12损伤细胞存活率的影响。结果 :H10 8浓度依赖性地增加K5 6 2 ADR及RBMECs细胞中Rh12 3的累积浓度。并可明显对抗Na2 S2 O4及SNP诱导的PC12细胞损伤 ,增加细胞存活率。结论 :H10 8具有一定的P gp逆转作 ,并可能具有一定的神经保护作用。其有可能成为一种新型、高效 ,特别是用于促进血脑屏障上药物转运的P gp逆转剂     

洛美利嗪对人白血病细胞K562/ADM多药耐药的逆转作用

目的：研究洛美利嗪(lomerizine，Lom)对人白血病细胞K562／ADM多药耐药逆转作用及机制。方法：使用MTT法检测Lom对K562／ADM多药耐药细胞柔红霉素(DNR)细胞毒性的影响，使用荧光分光光度计和流式细胞术分析Lom对K562／ADM多药耐药细胞胞内P—糖蛋白(P—glycoprotein，P—gp)底物—罗丹明123(rhodamine 123，Rh123)的累积情况。结果：Lom能明显提高DNR对K562／ADM多药耐药细胞的细胞毒作用，并可使胞内Rh123的浓度增加。K562敏感细胞株则不受影响。结论：Lom能显地抑制：K562／ADM多药耐药细胞上P—gp的活性，提高P—gp底物的胞内浓度，并增强其他抗癌药的细胞毒作用。     

苦瓜蛋白逆转K562／AO2细胞多药耐药性的研究

目的：研究非细胞毒性质量浓度苦瓜蛋白对耐阿霉素的人红白血病细胞株K562／AO2多药耐药性的逆转作用和促凋亡作用。方法：采用CCK-8法测定苦瓜蛋白的细胞毒性及其对K562／AO2细胞敏感性的影响,用流式细胞仪检测K562／AO2细胞经不同药物处理后细胞的凋亡情况。结果：苦瓜蛋白对K562／AO2细胞有一定的细胞毒作用,其非细胞毒性质量浓度为5μg／mL,非细胞毒性质量浓度苦瓜蛋白对K562／AO2细胞对阿霉素、长春新碱（VCR）和柔红霉素的耐药性都有部分逆转作用（分别为5．4、6．5和4．0倍）;5μg／mL苦瓜蛋白联合VCR诱导K562／AO2细胞凋亡,凋亡率为（19．38±1．06）％,而对照组为（1．64±0．27）％,单一苦瓜蛋白组为（3．79±0．82）％,单一VCR组为（9．83±0．98）％。结论：苦瓜蛋白能部分逆转人红白血病K562／AO2细胞对阿霉素、VCR和柔红霉素的耐药,一定剂量的苦瓜蛋白与VCR联合应用可增加肿瘤细胞凋亡率。     

克班宁对耐药细胞K562/HHT逆转作用的研究

目的　对克班宁 (CRE)逆转白血病耐药细胞系K5 6 2 /HHT的耐药性进行研究。方法　细胞毒试验采用MTT法 ,细胞内柔红霉素 (DNR)积累采用荧光分光光度法测定。结果　克班宁 5 μmol·L-1时显著增加高三尖杉酯碱(HHT)对K5 6 2 /HHT的细胞毒 ,细胞毒作用增强 13 0倍 ,同等条件下 8μmol·L-1维拉帕米为 19 4倍。克班宁能显著增加K5 6 2 /HHT细胞内DNR浓度。结论　克班宁通过增加多药耐药细胞内药物积累而调节多药耐药性     

红霉素逆转人肝癌细胞BEL-7402多药耐药性的研究

目的　研究红霉素 (ERY)对BEL 740 2细胞 (人肝癌细胞 )多药耐药性的逆转作用。方法　将BEL 740 2细胞连续培养在含阿霉素 (ADM )的培养液中诱导耐药细胞株BEL 740 2 /ADM ,用cell ELASA法检测细胞膜表面P gp的表达 ,细胞毒试验采用MTT法 ,用荧光分光光度法测定细胞内ADM浓度。结果　BEL 740 2 /ADM细胞表面P gp高度表达 ,除对ADM耐药外 ,对长春新碱 (VCR)和丝裂霉素(MMC)也有不同程度的交叉耐药 ;ERY可增强ADM、VCR、MMC对BEL 740 2 /ADM细胞的增殖抑制作用 ,可增加BEL 740 2 /ADM细胞内ADM的浓度而对细胞膜表面P gp的表达没有影响。结论　ERY通过竞争性地饱和BEL 740 2 /ADM细胞表面P gp通道 ,使细胞内药物外排减少、浓度增加 ,从而发挥对BEL 740 2 /ADM细胞多药耐药性的逆转作用     

洛美利嗪逆转K562/ADM细胞多药耐药性

目的研究洛美利嗪(lomerizine,Lom)逆转K562/ADM细胞多药耐药性的作用及机制。方法MTT法检测细胞毒作用,流式细胞仪研究Lom对ADM和长春新碱(vincristine,VCR)的K562/ADM细胞凋亡诱导作用的影响及对罗丹明123(rhodamine 123,Rh123)外排和P-糖蛋白(P-glycoprotein,P-gp)表达的作用。结果Lom明显提高ADM对K562/ADM多药耐药细胞的细胞毒作用及ADM和VCR的凋亡诱导作用,3,10和30 μmol·L^-1 Lom使K562/ADM对ADM的IC₅₀值由79.03 μmol·L^-1分别降至28.14,8.16和3.16 μmol·L^-1。Lom增加胞内ADM的蓄积浓度并抑制Rh123外排;但作用72 h后对K562/ADM细胞P-gp表达无影响。结论Lom通过抑制P-gp的活性逆转K562/ADM细胞的多药耐药性。     

氟哌啶醇对人红白血病耐多柔比星细胞株多药耐药性的逆转及其机制

目的　从临床常用药物中探寻逆转肿瘤耐药性的活性物质。方法　应用MTT法测定不同浓度Hal处理的瘤细胞对 0～ 2 0 μmol·L- 1多柔比星 (Dox)的敏感性的影响。RT PCR法分析 12 .5 μmol·L- 1氟哌啶醇 (Hal)处理后多药耐药基因 (MDR1) ,多药耐药相关蛋白 (MRP)和谷胱甘肽S转移酶Pi(GSTπ)mRNA表达的变化。通过流式细胞术观察 0 ,6 .2 5 ,12 .5 ,2 5 μmol·L- 1Hal对细胞内药物蓄积和细胞周期进程的影响。结果　Hal对K5 6 2 /Dox的耐药性具有明显的逆转作用。在 12 .5 ,6 .2 5及 3.12 5 μmol·L- 1时的逆转倍数分别为 8.35 ,4 .2 1及 2 .16。用 12 .5μmol·L- 1Hal处理后 ,MDR1及MRP的mRNA表达水平均呈现时间依赖性明显降低 ,分别较原水平下降76 .3%及 6 4.6 %。药后d 2GSTπmRNA表达下降6 6 .1% ,于d 3回升。Hal处理细胞lh后 ,Dox在细胞内蓄积量明显增加 ,并呈浓度依赖性 ;此外 ,Hal可明显增强Dox对K5 6 2 /Dox细胞的G2 /M阻滞作用 ,12 .5 μmol·L- 1浓度可以使 5 μmol·L- 1Dox的G2 /M阻断由单独应用时的 9.9%± 4 .3%增加到2 3.4 %± 3.0 %。结论　Hal具有较强的逆转K5 6 2 /Dox细胞MDR的作用 ,其逆转机制为多种途径 ,包括相关基因mRNA的表达下调 ,增加细胞内药物蓄积 ,增强Dox对K5 6 2 /Dox在G2     

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.