妥舒沙星的体内外抗菌作用研究

测定妥舒沙星的体内外抗菌活性。以同类氟喹诺酮类及其他抗菌药物为对照,测定了６８９株临床分离菌对药物的敏感性,结果显示,妥舒沙星对需氧革兰氏阳性球菌（除ＭＲＳＡ外）均有良好的抗菌作用,对金葡球菌、肺炎球菌和溶血性链球菌的抗菌活性高;妥舒沙星对需氧革兰氏阴性菌具强大的抗菌作用,对肠杆菌科细菌、流感杆菌和淋球菌的抗菌作用尤强;妥舒沙星对脆弱拟杆菌等厌氧菌亦具良好抗菌作用。妥舒沙星对需氧革兰氏阳性球菌及厌氧菌的作用明显优于环丙沙星、氧氟沙星和诺氟沙星,对需氧革兰氏阴性杆菌的作用与其他受试氟喹诺酮类相仿。妥舒沙星对小鼠实验性细菌感染具有明显保护作用,口服或静注妥舒沙星对金葡球菌的体内抗菌作用明显优于环丙沙星;对大肠埃希氏菌的抗菌作用优于或与环丙沙星相似;对铜绿假单胞菌的作用与环丙沙星相似。     

司帕沙星和妥舒沙星的体内外抗菌作用研究

目的观察国产司帕沙星、妥舒沙星及其它四种氟喹诺酮类抗菌药对成都地区780株临床分离菌的体外抗菌活性，并比较司帕沙星、妥舒沙星和环丙沙星对金葡球菌、大肠埃希菌和铜绿假单胞菌感染小鼠的体内抗菌活性。方法用琼脂稀释法测定国产司帕沙星和妥舒沙星的MIC50和MIC90，并与其它四种氟喹诺酮类抗菌药进行了比较。本文还测定了抗菌药对金葡球菌、大肠埃希菌和铜绿假单胞菌感染小鼠治疗的ED50结果体外试验表明司帕沙星和妥舒沙星能有效抑制或杀灭革兰阳性、革兰阴性菌及厌氧菌，显示了广谱抗菌活性。司帕沙星和妥舒沙星对革兰阳性菌的抗菌活性是环丙沙星的2～8倍，氧氟沙星和氟罗沙星的4～16倍，是诺氟沙星的16～32倍。司帕沙星对MRSA的抗菌活性与妥舒沙星相似，但优于环丙沙星、氧氟沙星、氟罗沙星和诺氟沙星。司帕沙星对大多数革兰阴性菌的抗菌活性与环丙沙星和妥舒沙星相似，是氧氟沙星、氟罗沙星和诺氟沙星的2～8倍。两药对厌氧菌的抗菌活性也较环丙沙星强。口服或皮下注射司帕沙星对金葡球菌和大肠埃希菌所致小鼠全身性感染的保护作用优于环丙沙星和妥舒沙星。同一给药途径下司帕沙星对铜绿假单胞菌所致小鼠全身性感染的保护作用与妥舒沙星和环丙沙星相似。三种受试药对金葡球菌和大肠埃希菌所致小鼠全身性感染的保护作用优于铜绿假单胞菌所致感染。结论司帕沙星和妥舒沙星对革兰阳性菌和厌氧菌的体外抗菌活性优于环丙沙星和其它药物，对大多数革兰阴性菌的抗菌活性与环丙沙星相似，但优于其它受试药。司帕沙星对金葡球菌和大肠埃希菌所致小鼠全身性感染的体内保护作用优于环丙沙星和妥舒沙星。同一给药途径下司帕沙星对铜绿假单胞菌所致小鼠全身性感染的保护作用与妥舒沙星和环丙沙星相似。     

舒他西林甲磺酸盐体内抗菌作用研究

舒他西林对４种细菌（金葡球菌、肺炎链球菌、大肠杆菌和肺炎克雷伯氏杆菌）共８个菌株分别感染小鼠的体内抗菌作用进行了研究，并以氨苄西林作为对照，以评价舒他西林对小鼠败血症的实验治疗疗效。实验结果显示：对金葡球菌、大肠杆菌和肺炎克雷伯氏杆菌，舒他西林的ＥＤ５０分别是氨苄西林ＥＤ５０的１／２～１／３、１／５～１／６和１／２～１／３，舒他西林的体内抗菌作用优于氨苄西林（Ｐ＜０．０１）。对氨苄西林敏感的肺炎链球菌，两药均显示出强大的抗菌活性，舒他西林的ＥＤ５０为氨苄西林的２～３倍，其抗菌活性逊于氨苄西林（Ｐ＜０．０１）。     

紫外分光光度法测定妥舒沙星片的含量

目的:研究甲苯磺酸妥舒沙星片的含量测定方法.方法:采用紫外分光光度法测定含量,以295 nm为测定波长,0.1mol·L-1盐酸作为溶剂.结果:甲苯磺酸妥舒沙星片在2.5～100 mg·L-1之间呈良好线形关系,r=0.999 9,平均回收率为98.96%(n=5).结论:本法简便、准确、稳定,适用于甲苯磺酸妥舒沙星含量的快速测定.     

硫肽类抗生素诺卡沙星抗革兰阳性菌的活性研究

目的：研究新型硫肽类抗生素诺卡沙星对临床常见革兰阳性致病菌的抗菌活性,探讨其抗菌机制,并与临床常用抗生素进行比较。方法：采用琼脂二倍稀释法测定最低抑菌浓度（Minimal Inhibition Concentration,MIC）,采用微量肉汤二倍稀释法测定最低杀菌浓度（Minimal Bactericidal Concentration,MBC）,采用小鼠体内抗菌保护实验测定体内抗菌活性。结果：诺卡沙星对甲氧西林耐药的葡萄球菌、青霉素耐药的肺炎球菌均显示较强的抗菌活性,对金黄色葡萄球菌MRSA、MSSA,表皮葡萄球菌MRSE、MSSE的MIC50值分别为0.016、0.016、0.0625、0.03125 mg· L-1,对肺炎球菌（PRSP/PISP）、化脓性链球菌、肠球菌的MIC50值为0.008、0.008、0.016 mg·L-1,其MIC50值为万古霉素的1/32-1/128,为莫西沙星的1/4-1/256,为利奈唑胺的1/32-1/256。注射用诺卡沙星经静脉给药后,对金黄色葡萄球菌感染小鼠均呈现体内保护作用,其ED50值明显低于对照药万古霉素和利奈唑胺,体内抗菌保护作用优于对照药。结论：诺卡沙星具有高效抗菌作用,明显优于万古霉素、利奈唑胺及莫西沙星,且与它们之间无交叉耐药现象。     

金葡球菌和肺炎链球菌在体内对莫西沙星耐药性研究

目的考察金葡球菌和肺炎链球菌在体内对莫西沙星的耐药性.方法利用大鼠肉芽肿袋模型测定金葡球菌和肺炎链球菌体内对莫西沙星的耐药性.体内试验所用的菌株是野生株(对莫西沙星敏感)、第一代耐药株(敏感性轻度下降)和多代耐药株(体外敏感性明显下降).不同菌株感染大鼠产生肉芽肿袋,用莫西沙星进行治疗.感染后1h(100mg@kg-1@d-1)或24h(100或50 mg@kg-1@d-1)开始治疗.每天采集肉芽肿袋渗出物并测定是否有莫西沙星耐药株产生.结果100mg@kg-1@d-1莫西沙星对金葡球菌和肺炎链球菌有明显的杀菌作用,感染后1h给药效果更明显.感染后24h开始治疗,且剂量降到50 mg@kg-1@d-1时,对野生株菌株仍然有效,但疗效不如100mg@kg-1@d-1.第一代耐药株可以像野生株一样被很快消灭,多代耐药株不能被低剂量莫西沙星所抑制.给予100mg@kg-1@d-1莫西沙星的动物模型中,肉芽肿袋中药物浓度与给予400mg@d-1的人血清药物浓度不相同.从各治疗组中分离出的菌株均未发现对莫西沙星耐药,试验期间突变株的MIC保持不变.结论莫西沙星在体内对肺炎链球菌和金葡球菌的野生株和第一代耐药株有显著的杀菌作用,既使浓度低于人体中预期的治疗浓度,仍可见到良好的杀菌效果;且G+菌对莫西沙星耐药的产生速度比其他氟喹诺酮药物慢.     

头孢硫脒对细菌感染小鼠败血症的体内抗菌作用

目的评价头孢硫脒对细菌感染小鼠败血症的体内抗菌作用。方法以最小致死剂量(MLD)细菌0.5 mL感染小鼠,建立小鼠败血症动物模型。尾静脉注射不同浓度药物0.2 mL,其中头孢硫脒、头孢唑啉、氨苄西林为2次给药,间隔12 h;头孢曲松和左氧氟沙星维持1次给药。记录给药后1~7 d内小鼠的成活率,用双层综合系统综合(BLISS)法计算半数有效量(ED50)、95%有效剂量(ED95),比较头孢硫脒与对照药品之间抗菌作用的差异。对3株标准菌株及7株临床分离致病菌采用单次给药方式进行了体内保护作用实验。结果头孢硫脒对肺炎链球菌、粪肠球菌均有较好的体内抗菌活性,单次给药ED50值在1.43~11.71 mg·kg^-1,与左氧氟沙星相似,显著优于头孢唑啉。对于肺炎链球菌、金黄色葡萄球菌和流感嗜血杆菌,头孢硫脒ED50值在0.78~14.78mg·kg^-1,均较单次给药明显下降。但对于粪肠球菌,2次给药的ED50值较单次给药有所上升,可能与血药浓度过低而影响体内保护作用有关。结论头孢硫脒对革兰氏阳性菌具有较好体内抗菌作用,特别对于肺炎链球菌和粪肠球菌。对于大多数菌种,头孢硫脒每天2次或多次给药更为合理。     

Clarithromycin的体内抗菌作用研究

新的１４元大环内酯ｃｌａｒｉｔｈｒｏｍｙｃｉｎ（ＣＲＭ）与红霉素（ＥＭ）对金葡球菌、化脓链球菌、肺炎链球菌、嗜血流感杆菌感染小鼠体内保护作用结果显示：口服ＣＲＭ对金葡球菌、化脓链球菌及肺炎链球菌的体内抗菌作用优于ＥＭ６．３～８．６倍。尤其对金葡球菌耐药菌及嗜血流感杆菌感染小鼠的半数保护剂量作用有效于ＥＭ的保护作用１７及１８倍，ＣＲＭ在体内具有良好的抗菌作用。     

国产头孢他美酯、头孢他美体内外抗菌作用研究

采用琼脂二倍稀释法评价国产头孢他美酯(cefetametpivoxil)、头孢他美对临床分离的558株致病菌的体外抗菌作用及其对小鼠感染细菌的体内疗效,并与进口头孢他美酯、头孢克洛、头孢噻啶、头孢唑林、司帕沙星、环丙沙星进行比较.结果表明头孢他美酯体外抗菌活性弱,对所试多数革兰氏阳性、阴性细菌的MIC为4～>128mg/L,而其母体化合物头孢他美体外呈现出较强的抗菌活性,对所试表葡球菌、肺炎链球菌、溶血性链球菌的MIC50在0.06～8mg/L(其中包括产β-内酰胺酶菌株),对金葡球菌非产酶株和产酶株的MIC50各是32和64mg/L;对革兰氏阴性菌中的大肠埃希氏菌(包括产β-内酰胺酶菌株),肺炎克雷伯氏菌、伤寒杆菌、痢疾杆菌、变形杆菌、硝酸盐阴性不动杆菌、普鲁威登斯菌、阴沟肠杆菌、粘质沙雷氏菌及鲍氏不动杆菌等均敏感,MIC50在0.5～8mg/L;本品对铜绿假单胞菌无效.头孢他美对金葡球菌、表葡球菌的抗菌活力不如第一、二代头孢菌素,如头孢噻啶、头孢唑林、头孢克洛,但对肺炎链球菌、溶血性链球菌的活力比头孢克洛、头孢噻啶和头孢唑林强4～8倍,与司帕沙星、环丙沙星相近.头孢他美对革兰氏阴性杆菌的抗菌活力强于头孢克洛、头孢噻啶,头孢唑林2～64倍,比不上司帕沙星和环丙沙星.头孢他美对厌氧菌的抗菌活力较头孢克洛强,MIC50在16～32mg/L.头孢他美为杀菌剂,MBC浓度为MIC浓度的2～4倍.在2～4MIC浓度时呈现明显的杀菌效力.接种菌量、pH值改变、血清浓度变化对头孢他美和头孢他美酯的MIC值影响不显著.体内抗菌实验表明,头孢他美酯口服给药对金葡球菌、肺炎链球菌、大肠埃希氏菌、肺炎克雷伯氏菌感染小鼠呈现出较佳的体内疗效,比头孢克洛强2～20倍.本实验结果表明,国产头孢他美酯体内外抗菌作用与进口头孢他美酯基本一致.     

替比培南匹伏脂的体外抗菌作用研究

目的 评价替比培南匹伏脂的体外抗菌作用.方法 用琼脂对倍稀释法测定替比培南匹伏脂对519株临床分离菌的体外抗菌活性.结果 对革兰阳性球菌中的肺炎链球菌、化脓性链球菌及对甲氧西林敏感的金葡菌和凝固酶阴性的葡萄球菌,替比培南匹伏脂均显示良好的抗菌活性.尤其是对青霉素不敏感肺炎链球菌,替比培南匹伏脂的MIC50最低,为0.25 mg·L-1.本品对流感嗜血杆菌、卡他莫拉菌、产ESBLs和不产ESBLs的肺炎克雷伯菌和大肠埃希菌、易产诱导酶的阴沟肠杆菌、产气肠杆菌、枸橼酸杆菌、粘质沙雷菌的MIC50为≤0.03～5.00 mg· L-1,低于其他5种抗菌药物.结论 替比培南匹伏脂对社区感染中常见病原菌有较好的抗菌活性.     

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.     

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.     

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.