唑类抗真菌药物的筛选及抗菌机制研究

目的 为了获得体外抑菌活性较好的抗真菌药物,筛选了14种唑类化学合成药物(A1～A7和B1～B7)的体外抗真菌活性。以白色念珠菌为代表试验菌株,初步探讨其抗真菌机制。方法 通过微量液体稀释法测定药物的最小抑菌浓度(minimum inhibitory concentration, MIC),最小杀菌浓度(minimum fungicidal concentration, MFC),琼脂平板计数法测定时间杀菌曲线;棋盘稀释法测定联合用药,评估化合物体外抑菌效果,筛选获得高效抗真菌化合物;以化合物B7为基础,通过液体菌丝诱导观察白色念珠菌菌体形态变化,通过XTT法测定生物被膜形成抑制,通过真菌细胞内氧化应激活性氧初级荧光测定,初步探究化合物对白色念珠菌的体外抗真菌活性及其作用机制。结果 本研究从14种唑类化合物中筛选获得具有良好体外抗真菌效果化合物B7,以白色念珠菌ATCC SC5314为代表,其MIC为0.062 5μg·mL^-1,MFC为0.25μg·mL^-1,且其杀菌活性具有剂量依赖性的特点,与氟康唑联合具有累加作用。菌丝诱导实验表明B7对...     

阴道分泌物的霉菌鉴定及药敏试验

对临床125例患霉菌性阴道炎的阴道分泌物进行鉴定和药敏试验.结果白色念珠菌的检出率最高占73.6%,其次为热带念珠菌占22.4%.对125株念珠菌进行5种抗真菌药物的药敏试验,两性霉素B、制霉菌素、伊曲康唑的MIC50均为0.78 μg·ml-1,MIC90均为3.13 μg·ml-1;克霉唑的MIC50为6.25 μg·ml-1,MIC90为25 μg·ml-1,氟康唑的MIC50为>25 μg·ml-1.氟康唑和克霉唑对白色念珠菌的作用强于热带念珠菌;而两性霉素B、制霉菌素和伊曲康唑对两种菌的作用差别不大.因此在有条件的情况下,应对阴道分泌物的霉菌进行鉴定和药敏试验以指导临床合理用药.     

氨基丁酸联合卡泊芬净抗白色假丝酵母菌生物被膜协同作用研究

目的探讨氨基丁酸联合卡泊芬净抗白色假丝酵母菌生物被膜的协同作用。方法利用白色假丝酵母菌标准菌株SC5314,采用生物被膜形成实验,分为空白对照组、氨基丁酸单用组、卡泊芬净单用组、氨基丁酸联合卡泊芬净组,对比各组生物被膜形成情况。采用XTT还原法测定氨基丁酸、卡泊芬净单用以及氨基丁酸联合卡泊芬净对成熟生物被膜细胞代谢活性的抑制作用。采用YNB培养基菌丝形成实验,考察氨基丁酸与卡泊芬净合用是否具有协同抑制菌丝形成的作用。结果卡泊芬净0.1μg·mL-1联合氨基丁酸0.1μmol·L-1对白色假丝酵母菌SC5314生物被膜的形成具有显著的抑制作用。此外,XTT还原法测定氨基丁酸6.25μmol·L-1联合卡泊芬净0.1μg·mL-1时降低被膜细胞代谢活性的效率能够达到约15%。采用YNB培养基形成菌丝,氨基丁酸6.25μmol·L-1联合卡泊芬净0.1μg·mL-1对白色假丝酵母菌SC5314菌丝形成能力有显著的抑制作用。结论氨基丁酸联合卡泊芬净表现出显著的体外协同抗白色假丝酵母菌标准菌株SC5314生物被膜作用。     

抗真菌药和利福平对念珠菌、曲菌、隐球菌的体外联合作用

本文首先测定34株念珠菌、曲菌和隐球菌对两性霉素B、5-氟胞嘧啶、酮康唑、利福平的MIC,然后用棋盘式滴定测定药物的体外联合抗真菌作用。未能证明两性霉素B加5-氟胞嘧啶或酮康唑、5-氟胞嘧啶加酮康唑有协同作用。但两性霉素B和利福平则对34株中的33株有协同抗真菌作用。协同作用对新型隐球菌和白色念珠菌尤为显著。研究了三种药物的体外联合抗真菌作用,加入第三种药物未能显著增加抗真菌活力。在杀菌曲线研究中,两性霉素B和利福平对白色念珠菌B311的协同作用进一步被证实。     

土槿乙酸抗白色念珠菌的敏感性及作用机理的电镜研究

目的:测定土槿乙酸(pseudolaric acid B,PLAB)对白色念珠菌(caudida albicans)标准菌株C1a的最低抑菌浓度(MIC),并在透射电镜下观察经PLAB作用后,白色念珠菌超微结构的改变,探讨其作用机制,从而为抗白色念珠菌的中药开发提供理论依据.方法:用液体稀释法检测PLAB对白色念珠菌C1a的MIC,透射电镜下观察经不同浓度PLAB作用前后白色念珠菌C1a超微结构的改变,两性霉素B(AmB)为阳性对照药物.结果:PLAB对白色念珠菌C1a的MIC为32 μg/ml.透射电镜观察发现,AmB处理组白色念珠菌C1a形态基本正常,但细胞壁结构疏松,有裂口,细胞膜缺失较严重.胞浆内容物漏出.经PLAB处理组白色念珠菌C1a细胞变形,结构模糊,细胞壁疏松,有裂口,细胞膜连续性破坏,进而破碎成碎片互相融合,细胞器肿胀乃至坏死溶解,甚至胞浆内容物全部漏出呈"空壳"状.结论:PLAB有抗白色念珠菌作用.可能通过破坏白色念珠菌的细胞壁、细胞膜、细胞核的结构而达到抗真菌作用.     

复方两性霉素B溶液治疗耳真菌病临床疗效研究

目的：观察两性霉素B联合利福平复方溶液治疗耳真菌病的临床疗效,进而探讨有效的治疗方法。方法：（1）运用棋盘式微量液基稀释法测定两性霉素B联合利福平对白色念珠菌标准菌株（编号ATCC90028）的体外最低抑菌浓度（MIC）值,在此基础上计算部分抑菌浓度指数（FIC）;依据FIC值判断两药联用是否有协同作用;（2）经真菌培养及鉴定确定为耳真菌病的60例患者中,根据临床症状与体征轻重的得分标准,随机分为3组,分别用两性霉素B、两性霉素B联合利福平复方溶液和3%水杨酸酒精滴耳液外耳道局部治疗1周、2周后,观察3组愈显率;并随访1年。结果：（1）两药联用的FIC指数小于0.5;（2）3组愈显率比较,第1周：两性霉素B联合利福平复方溶液组愈显率最高,较其他2组有统计学意义（P<0.05）,第2周：两性霉素B和利福平组与两性霉素B组愈显率相比无统计学意义（P>0.05）,以上2组分别与3%水杨酸酒精滴耳液组愈显率相比有统计学意义（P<0.05）。随访一年,水杨酸酒精滴耳液组复发率比其他2组高,差异有统计学意义（P<0.05）。结论：（1）两性霉素B联合利福平对真菌有协同作用;（2）两性霉素B联合利福平复方溶液外用制剂是治疗耳真菌病较理想的外用药物,且具有便于取材、配制简单、使用方便、起效快等优点,值得向基层医院推广。     

两性霉素B治疗肺部念珠菌感染32例

咪唑类和两性霉素B(AMB)是迄今治疗深部真菌感染的主要药物,目前白色念珠菌对氟康唑的耐药性越来越高,非白念念珠菌对氟康唑不甚敏感[1],而AMB对白色念珠菌特别是非白念珠菌的敏感率则较高[2].常用的含脂类两性霉素B其抗菌谱和抗菌作用与两性霉素B常规制剂相同,肾毒性较低,但其价格昂贵,多数患者难于接受,尚不宜作为一线应用,仅适用于对两性霉素B常规制剂无效(已用常规制剂总量＞0.5 g)或不能耐受的患者[3].本文应用AMB治疗肺念珠菌感染32例患者,疗效满意,且不良反应轻微,现报道如下.     

黄芩苷对白色念珠菌生物膜形成的体外抑制作用

目的：研究黄芩苷体外对白色念珠菌生物膜形成的影响。方法扫描电镜下观察不同培养时间的生物膜形态,并用XTT减低法检测黄芩苷对白色念珠菌生物膜活性的影响,用结晶紫含量测定法检测黄芩苷对白色念珠菌生物膜生物量的影响。结果白色念珠菌在48h时形成成熟的生物膜。黄芩苷在浓度为8．0mg? mL －1时使白色念珠菌生物膜活性及生物量分别减少（90．6±5．2）％和（90．3±2．6）％,生物膜已基本无活性。结论黄芩苷对白色念珠菌生物膜的形成具有抑制作用。     

两性霉素B脂乳治疗深部真菌病

两性霉素 B 是临床治疗深部真菌病的首选药,因其副作用大而难以获得满意的效果。作者用内源性脂肪包封两性霉素 B,减轻其急性毒性,并对实验性小鼠念珠菌病和隐球菌病的治疗进行研究,取得明显效果。方法:(1)常规培养白色念珠菌7N 株和新型隐球菌 C-28株后,给5周龄雄性小鼠分别从尾静脉和脑内接种1ml(1.0×10~7CFU/ml)白色念珠菌7N 悬浮液和0.03ml(3.3×10~7CFU/ml)新型隐球菌 C-28菌液;(2)依 K_(IRSH)R 法制备不同浓度(0.25,0.50,1.0 mg/ml)的两性霉素 B 脂乳,对照剂为含脱氧胆酸钠和溶解剂的两性霉素 B;(3)给予小鼠不同浓度的两性霉素 B 脂乳,观察6周,测定 LD_(50),对照剂为20％内源性脂肪;(4)对     

Etest法测定伊曲康唑对曲霉和酵母菌的体外抗菌活性

目的:测定伊曲康唑、两性霉素B和氟康唑对曲霉和酵母菌的体外抗菌活性.方法:采用Etest法测定伊曲康唑、两性霉素B和氟康唑对40株曲霉和163株酵母菌的体外最小抑菌浓度(MIC).结果:对烟曲霉、黄曲霉和构剿曲霉,伊曲康唑比两性霉素B和氟康唑有较低的MIC值,3种药的MIC值范围分别(0.125～1.5),(0.25～64)和(192～>512)mg·L-1.对白念珠菌、热带念珠菌和近平滑念珠菌,3种药均有较低的MIC值,其MIC范围均为(0.004～12)mg·L-1.对光滑念珠菌和克柔念珠菌,氟康唑的MIC50分别为48和128mg·L-1,MIC90分别为512和256mg·L-1,高于两性霉素B(MIC50分别为0.38和1mg·L-1,MIC90分别为0.75和1.5mg·L-1)和伊曲康唑(MIC50分别为4和1mg·L-1,MIC90分别为64和3mg·L-1).结论:伊曲康唑对多数曲霉和酵母菌有较好的体外抗菌活性.     

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.     

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.