平阳霉素对HeLa细胞DNA的体外断裂作用

用琼脂糖电泳及DNA电镜技术观察平阳霉素对HeLa细胞DNA的体外断裂作用。药物处理的DNA经琼脂糖电泳及溴乙锭染色后,紫外荧光摄影。0.5μg DNA与5μg/ml药物作用2h及200μg/ml作用10min即可见DNA断裂。应用碱性蛋白膜展层法制作DNA电镜标本,5μg/ml DNA与10μg/ml药物作用2h可见自然弯曲的DNA长链(±SD=5.97±1.95μm)被切割成DNA短段(±SD=0.73±0.24μm),对照组DNA长度长于药物处理组(P<0.01)。     

三尖杉酯碱和高三尖杉酯碱与白血病细胞DNA的结合实验

本文用琼脂糖电泳观察国产三尖杉酯碱(H)及高三尖杉酯碱(H.H)与白血病细胞DNA的作用模式。实验发现H及H.H在高浓度(800μg/ml),37℃作用16h,可与DNA发生嵌合效应,48h这种现象更为明显,同时该过程也伴有一定程度的DNA断链效应。阿霉素在低浓度(50μg/ml)作用30min即可显示嵌合效应。本实验表明H.H对白血病细胞DNA的嵌合能力较H有所增强,但两者所见嵌合效应与阿霉素比较相距甚远。     

阿克拉霉素A对HeLa细胞核仁及细胞表面超微结构的影响

本文报道用透射电镜及扫描电镜观察国产阿克拉霉素A对HeLa细胞核仁及细胞表面超微结构的影响。阿克拉霉素 A0.5μg/ml处理 10分钟即可见核仁内出现多个核仁纤维中心,继而出现核仁分离及微球体,核仁的这些超微结构改变与该药特异性抑制rRNA生物合成相关。阿克拉霉素A0.5μg/ml作用8小时细胞表面微绒毛消失,继而细胞表面破裂,细胞崩解提示细胞膜可能也是阿克拉霉素作用的靶位之一。     

阿克拉霉素B、阿霉素和小檗碱对人外周血NK细胞活性影响的初步研究

本文研究了阿克拉霉素B、阿霉素和小檗碱对人外周血NK细胞活性的影响.NK细胞活性由测定~(51)Cr从NK细胞作用的标记K562细胞的释放率来决定.阿克拉霉素B(0.5和1.Oμg/ml),阿霉素(0.5和1.0μg/ml)和小檗碱(1.0和10μg/ml)作用1小时后,未见对NK细胞活性有显著影响,提示三个药物可能即不明显抑制也不促进NK细胞的细胞毒作用.阿克拉霉素B和小檗碱在高浓度时表现轻微的促进作用,但阿霉素有轻微抑制作用.三个药物均有不同程度地增加靶细胞~(51)Cr的自然释放率,以阿霉素最强,提示有细胞膜毒性产生.因而尚难肯定阿克拉霉素B和小檗碱的NK细胞活性促进作用.     

雷公藤内酯注射液对人结肠癌细胞DNA嵌合能力的观察

本文用琼脂糖电泳观察阿霉素和雷公藤内酯注射液对结肠癌细胞DNA 的嵌合作用。实验发现,不同批号的雷公藤内酯注射液对结肠癌细胞DNA 嵌合能力有明显差异,并同阿霉素,随制剂存放时间延长,药物对DNA 的嵌合能力减弱。提示本实验方法可反映药物制剂质量的稳定性。     

5种抗肿瘤抗生素对人白血病细胞DNA嵌合能力的观察

采用琼脂糖电泳法观察５种抗癌药对白血病细胞ＤＮＡ的嵌合能力。结果发现表阿霉素同进口阿霉素在５０μｇ／ｍｌ浓度时可与ＤＮＡ发生嵌合效应；国产阿霉素在较高浓度（１００μｇ／ｍｌ）和柔红霉素需高浓度（２００μｇ／ｍｌ）才显示嵌合效应；而米托蒽醌在较低浓度（２５μｇ／ｍｌ）即可发生此作用。本实验体现了作用机制类同的抗肿瘤药物对ＤＮＡ嵌合能力的差异。     

雷公藤内酯醇与人乳腺癌细胞大分子DNA作用模式的探讨

采用药物与DNA作用的体外检测方法，以DNA嵌入剂表阿霉素（EDR）作对照，从分子药理水平研究雷公藤内酯醇（TL）对乳腺癌细胞DNA的作用模式。实验发现TL在120μg／ml浓度，37℃作用24h可与DNA模板结合，同EDR呈嵌合效应，但嵌入DNA尚不牢固，易发生解离；EDR在较低浓度（50μg／ml）作用30min即可显示明显的嵌合效应且是不可逆的。说明TL对乳腺癌细胞DNA的作用模式为嵌合逆行模型，嵌合能力远低于EDR，与DNA结合亦不可能是其抗癌主效应。     

孤啡肽逆转人白血病K562/ADM细胞耐药性的研究

目的 探讨孤啡肽对人白血病K562/ADM细胞对阿霉素耐药性的逆转作用.方法 测定孤啡肽的细胞毒性及其对K562/ADM细胞药物敏感性的影响,计算耐药逆转倍数.瑞士染色观察药物作用后K562/ADM细胞形态的改变;流式细胞仪检测阿霉素单用或与孤啡肽联用K562/ADM细胞凋亡百分率;DNA琼脂糖凝胶电泳观察孤啡肽与阿霉素联用后K562/ADM细胞内DNA的损伤程度.结果 非细胞毒性剂量的孤啡肽(10-7mol/L)作用于K562/ADM细胞时,对阿霉素耐药起到了部分逆转作用,使K562/ADM细胞的IC50由原来的(46.99±0.25)μg/ml降低至(23.11±0.29)μg/ml,其逆转倍数为2.03倍;孤啡肽(10-7mol/L)和阿霉素(20μg/ml)联合处理K562/ADM细胞48h,K562/ADM细胞呈典型的凋亡形态改变;细胞的凋亡率达到(18.73±3.90)%,明显高于两种药物在相同条件下单独作用的效果,P＜0.01;结论 孤啡肽能诱导K562/ADM细胞凋亡,从而能逆转K562/ADM细胞的耐药性,提高阿霉素的敏感性.     

博莱霉素A_2B_2和A_5对人癌细胞脱氧核糖核酸的断链效应

本文观察比较了博莱霉素A_5(国产)、博莱霉素A_2B_2(日本)和博莱霉素A_2B_2国际标准品对于人体胃癌细胞的总脱氧核糖核酸和其50kb部分,以及人舌癌细胞的总脱氧核糖核酸的体外断链效应。作用后脱氧核糖核酸经琼脂糖微型快速电泳和溴化乙锭染色后,紫外荧光摄影。显示三种博莱霉素产品对人癌细胞双链脱氧核糖核酸的作用模型电泳图。并观察了作用时间及药物浓度的效应。人体DNA10μg在博莱霉素400μg/ml(～0.27mM)浓度下,37℃作用30分钟后,即可观察到人体DNA的断裂效应;37℃作用120分钟后,几乎全部人体DNA分子均被切割断链。人体DNA20μg在系列浓度的博莱霉素存在下,37℃作用120分钟,观察到博莱霉素断链的最低有效浓度为1μg/ml(～0.67μM)左右。没有发现博莱霉素-人胃癌细胞脱氧核糖核酸与博莱霉素-人舌癌细胞脱氧核糖核酸的作用模型之间有何明显差别。 本文还讨论了以人体细胞脱氧核糖核酸为对象,研究抗癌药物作用模式的实践意义,和本实验系统正被应用于人体“癌基因”(Oncogenes)有关研究的价值。     

新抗病毒抗生素变活霉素A

变活霉素A为一新的蒽环类广谱抗病毒抗生素,在组织培养内对4株单纯疱疹Ⅰ型病毒(HSV-1),4株单纯疱疹Ⅱ型病毒,流感甲_3病毒及柯萨奇B_6病毒的致细胞病变作用均有抑制活性,IC_(50)为6.25～12.5μg/ml。相同剂量可降低HSV-1繁殖量 1.5～3.5个对数值(log10)。细胞感染HSV-1后 4～10小时再用变活霉素A处理,仍可抑制,推迟细胞病变的发展.250～500μg/ml变活霉素A在无细胞系统内对HSV-2 DNA聚合酶,人免疫缺陷病毒(HIV-1)逆转录酶,鸭乙型肝炎病毒DNA聚合酶及牛胸腺DNA聚合酶α均无抑制活性。     

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.     

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.     

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.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

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.