抗生素89—07多次给予大鼠的毒性

抗生素８９－０７按每天３０、１００和１８０ｍｇ／ｋｇｉｐ给予大鼠，连续９０天，共检测７项血液学指标，１０项生化指标及１０多种组织脏器。给药后２周内，１８０ｍｇ组部分动物出现行走缓慢，有３只动物死于给药后１７－２１天。３０天测定时，１００和１８０ｍｇ组的肌酐和尿素氮含量升高。     

大鼠肌注抗生素89－07、阿米卡星和庆大霉素肾毒作用的比较

抗生素８９－０７、庆大霉素、阿米卡星按每天５０、１００、１５０ｍｇ／ｋｇ，ｉｍ给予大鼠。分别于给药后５、１０、１５天处死动物，取样作肾功能和肾脏光镜形态学检查，比较评价了３种氨基糖苷类抗生素的肾脏毒性，ｉｍ庆大霉素１００ｍｇ／（ｋｇ·ｄ）以上剂量的动物，给药后７天就出现死亡，５０ｍｇ组随给药时间的延长，肾功能异常的指标逐渐增多，肾小管上皮细胞也由个别散在性的坏死发展到大片状和广泛性的严重坏死。抗生素８９－０７和阿米卡星５０ｍｇ组，仅见个别肾功能指标异常，肾小管上皮细胞仅见混浊肿胀等变性，即使是１００ｍｇ组的肾小管上皮细胞坏死的程度也没有庆大霉素５０ｍｇ组严重。上述结果表明，抗生素８９—０７的肾毒作用明显比庆大霉素轻。     

抗生素89—07多次给予Beagle犬的毒性

用４种不同剂量［３、１０、３０和６０ｍｇ／（ｋｇｄ）］的抗生素８９－０７ｉｖ给予Ｂｅａｇｌｅ犬，连续９０ｄ，主要中毒表现是：给药１４ｄ内，６０ｍｇ组动物出现四肢无力；药后６０ｄ大于１０ｍｇ剂量组的动物肌酐及尿素氮升高，红细胞、血红蛋白及血细胞比容降低。病理组织学的变化，主要是肾小管上皮细胞变性和坏死，受损程度随剂量增加而加重。肾脏重量有随剂量加大而增加的趋势。３ｍｇ组动物未见明显异常，功能与病理形态学的改变均证明抗生素８９－０７与其它氨基糖苷类抗生素一样，反复给药的主要毒性靶器官是肾脏。在本试验条件下，Ｂｅａｇｌｅ犬ｉｖ１０ｍｇ可视为基本安全剂量。     

大鼠肌注抗生素89—07,阿米卡星和庆大霉素肾毒作用的比较

抗生素８９－０７、庆大霉素、阿米卡星按每天５０、１００１５０ｍｇ／ｋｇ，ｉｍ给予大鼠。分别于给药后５、１０、１５天处死动物，取样作肾功能和肾脏光镜形态学检查，比较评价了３种氨基糖苷类抗生素的肾脏毒性，ｉｍ庆大霉素１００ｍｇ／（ｋｇ．ｄ）以上剂量的动物，给药后７天就出现死亡。     

新型抗生素89—07对大鼠肾毒性的评价

抗生素８９－０７是庆大霉素新型的衍生物，给大鼠肌注３０、９０和１２０ｍｇ／ｋｇ，每日１次，为期７ｄ或２１ｄ，并与庆大霉素（ＧＭ）等剂量进行肾毒性比较，结果表明，ＧＭ１２０ｍｇ／ｋｇ组引起大鼠肾功能的损害包括尿蛋白、尿糖、尿酶的活性，一般毒性症状和体重增长受抑制比抗生素８９－０７等剂量严重。病理组织学检查证明，ＧＭ和抗生素８９－０７的９０和１２０ｍｇ／ｋｇ剂量主要是肾近曲小管上皮细胞损伤，抗生素８９－０７仅有轻度近曲小管上皮细胞退行性改变，而ＧＭ除细胞退行变性外，有部分细胞坏死，肾小管内有蛋白管型和细胞管型。     

抗生素89－07多次给予Beagle犬的毒性

抗生素８９－０７多次给予Ｂｅａｇｌｅ犬的毒性李培忠，郑德琪，沈伽弟，孙永立，韩铁，于文梅，沈菊英，翟文生，李先武，刘晓明（军事医学科学院毒物药物研究所，北京１００８５０）用４种不同剂量（３、１０、３０和６０ｍｇ）（ｋｇ·ｄ））的抗生素８９－０７ｉｖ给...     

抗生素89—07小鼠骨髓嗜多染红细胞微核试验

用小鼠骨髓嗜多染红细胞微核试验，检查抗生素８９－０７的遗传效应，根据小鼠ＬＤ５０，选择１０、２０、４０ｍｇ／ｋｇ三个剂量组，一次静脉给予。给药２４ｈ时采样制作标本。镜检结果经统计表明三个剂量组与阴性对照组相比嗜多染红细胞微核无明显增加。表明小鼠微核试验为阴性。抗生素８９－０７不是一个断裂剂。     

抗生素89—07的局部刺激性试验

用新西兰大白兔比较了抗生素８９－０７和阿米卡星（ＡＭＫ）肌肉注射的肌肉刺激性。１００ｍｇ受试药物（按碱基计算）溶于１．０ｍｌ生理盐水中，１次注入一侧股四头肌。给药２４和９６ｈ，根据肉眼观察和病理组织学检查结果，判断局部肌肉损伤程度。本试验结果证明，肌注抗生素８９－０７引起的肌肉损伤程度比ＡＭＫ轻。     

抗生素89－07、庆大霉素和阿米卡星对豚鼠连续肌注15天的耳毒性初步比较

从功能与形态学两方面比较抗生素８９－０７、庆大霉素（ＧＭ）、阿米卡星（ＡＭＫ）对豚鼠耳蜗的影响，在豚鼠连续肌注１５天，停药１４天后，发现２００ｍｇ／（ｋｇ·ｄ）组庆大霉素与阿米卡星对耳蜗毛细胞平均损伤享为６３％与１０％，而相同剂量的抗生素８９－０７平均损伤率仅０．３％，说明抗生素８９－０７耳毒性极小，比ＧＭ和ＡＭＫ更为安全。     

抗生素89－07联合氟氧头孢实验治疗mec A基因阳性MRSA感染小鼠败血症体内抗菌疗效

应用ｍｅｃＡ基因阳性的甲氧西林耐药金葡球菌２株临床分离菌株，金葡球菌９２－１０６与８９－１８７感染小鼠引起的小鼠败血症实验模型，评价抗生素８９－０７与氟氧头孢联合方案的体内抗菌活性并与去甲万古霉素单独给药进行比较。结果表明去甲万古霉素治疗金葡球菌９２－１０６和８９－１８７引起的小鼠ＭＲＳＡ感染的半数有效剂量ＥＤ５０值分别为５．８±１．１和４．１±０．８ｍｇ／ｋｇ，均显著低于抗生素８９－０７（１０．０，１０．５ｍｇ／ｋｇ）或氟氧头孢（２６；９，２９．２ｍｇ／ｋｇ）。抗生素８９－０７与氟氧头孢联合治疗ＭＲＳＡ９２－１０６与８９－１８７感染小鼠的ＥＤ５０值分别为３．８与２．５ｍｇ／ｋｇ。均显著低于去甲万古霉素、抗生素８９－０７和氟氧头孢相应的ＥＤ５０值。说明抗生素８９－０７与氟氧头孢联合方案的体内抗菌活性比去甲万古霉素强，具有统计学显著意义（Ｐ＜０．０１）。表明两药联合具有很好的体内协同作用。     

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.

---

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.