厄贝沙坦与氢氯噻嗪联用在肾性高血压大鼠体内药动学-药效学关系研究

目的:应用药动学-药效学结合模型研究厄贝沙坦与氢氯噻嗪联用在肾性高血压大鼠体内单剂量及多剂量用药时的药动学-药效学关系。方法:将SD大鼠制备成2肾1夹型肾性高血压模型,给大鼠单剂量或多剂量灌胃给药,分别于第1天和第8天连续的预定时间点测定血药浓度,同时测定动脉收缩压(SBP)和动脉舒张压(DBP)等药物效应,建立效应室药动学-药效学结合模型并计算相关的药动学和药效学参数。对单用、联用及单剂量、多剂量的药动学-药效学规律进行定量研究。结果:厄贝沙坦的药动学特征呈二室模型,氢氯噻嗪在非稳态和稳态条件下均未改变厄贝沙坦的药动学参数,而在稳态条件下,厄贝沙坦可增高氢氯噻嗪的血药浓度及曲线下面积。厄贝沙坦和氢氯噻嗪联用降压效应优于单用的效应。药物效应和效应室浓度之间符合Sigmoid-Emax药效学模型。单剂量下药物效应与血药浓度间存在滞后现象,多剂量下滞后现象消失。Emax、EC50、Keo等药效学参数在厄贝沙坦组和两药联用组之间的差异有统计学意义。结论:建立了PK-PD定量数学模型研究厄贝沙坦和氢氯噻嗪联用在大鼠体内单剂量和多剂量用药后药动学-药效学(暴露-反应)关系的规律,并提供了相关的药动学和药效学参数,可为临床合理用药提供参考依据。     

美托洛尔在家兔和肾性高血压大鼠体内的药代动力学-药效学结合模型

正常家兔 im1 0 ,1 5mg· kg-1和肾性高血压大鼠 ig美托洛尔 ,研究药物在两种动物体内降低心率和血压效应与药代动力学之间的关系 ,用高效液相荧光检测药物浓度 ,结果显示 :美托洛尔血药浓度时间曲线均符合二室模型 ,其降低心率和血压的最大效应明显滞后于血药浓度 .应用 Sheiner等提出的药代动力学 -药效学结合模型 ,用多维函数一次搜寻法对效应室药物浓度 ( Ce)与抑制心率及降低血压效应进行拟合 ,得出美托洛尔在两种动物体内的Ce和抑制心率效应之间的关系符合 Sigmoid- Emax模型 ,而 Ce 和降低血压效应之间的关系符合 β-功能模型 ,以上效应的预测值和实测值拟合良好 ,因此认为以上数学模型可以应用于动物实验中效应的预测 .     

蝙蝠葛苏林碱和蝙蝠葛碱在犬体内的药动学-药效学模型

目的：研究蝙蝠葛苏林碱和蝙蝠葛碱在beagle犬体内的药动学-药效学结合模型,并比较两种药物对其心电、血压和血流动力学的作用。方法：利用反相高效液相色谱法测定其血药浓度,生理记录仪观察药理效应,并计算药动学和药动学-药效学结合模型参数．结果：血药浓度-时间数据符合二房室开放模型．药效与效应室药物浓度之间的关系符合sigmoid-Emax模型．主要药动学和药动学-药效学结合模型参数在两种药物间差异无显著性．结论：蝙蝠葛苏林碱和蝙蝠葛碱在beagle犬体内的处置规律和对心血管系统的抑制作用基本-致。     

尼索地平控释贴剂在自发性高血压大鼠体内的药动学-药效学结合模型的建立

目的:建立尼索地平控释贴剂(NCRP)在自发性高血压大鼠(SHR)体内的药动学-药效学(PK-PD)结合模型。方法:将SHR随机分为贴剂(NCRP)组和片剂(尼索地平片)组,每组6只,植入微透析探针,按尼索地平计每只给药5 mg。收集给药后36 h内的血浆微透析液,采用高效液相色谱法测定尼索地平血药浓度,Win Nonlin 5.3软件计算药动学参数,以心率和血压为药效学指标,进行PK-PD结合模型研究。结果:与尼索地平片比较,NCRP具有控释效果;NCRP药物效应与效应室浓度以Sigmoid-Emax模型拟合,心率和收缩压的PK-PD模型主要参数分别为Emax:(2.65±0.06)、(10.71±0.87),EC50:(83.65±35.25)、(1.29±0.26)ng/ml,γ:(0.83±0.91)、(1.2±0.35),Keo:(0.37±0.53)、(0.91±0.24)h-1。结论:成功建立了NCRP在SHR体内的PK-PD结合模型。     

厄贝沙坦在健康志愿者体内的药代动力学-药效学结合模型

目的研究厄贝沙坦在健康志愿者体内的药代动力学-药效学结合模型,探讨其临床药效学特征。方法18例健康志愿者厄贝沙坦片口服给药,测定血药浓度,同时测量收缩压(SBP)、舒张压(DBP)及心率(HR)等药效指标。计算厄贝沙坦的药动学参数,并根据sheiner效应室模型理论,计算药效学参数。结果厄贝沙坦的血药浓度时间曲线呈二室模型;厄贝沙坦抑制SBP和DBP的效应滞后于血药浓度,药效与血药浓度之间存在逆时针滞后环,药效和效应室浓度的关系符合SigmoidEmax模型。厄贝沙坦抑制SBP和DBP的药效学参数Emax分别为(14.8±1.5)和(9.8±2.1)mmHg,EC50分别为(0.29±0.11)和(0.18±0.07)mg·L-1,Keo分别为(0.62±0.09)和(0.68±0.07)h-1。结论建立了厄贝沙坦在健康者体内的药代动力学-药效学结合模型,有利于临床合理用药。     

蝙蝠葛碱在Beagle犬体内的药动学与其对心电图的影响

目的:建立药动学-药效学结合模型分析蝙蝠葛碱在犬体内药动学与其对心电图影响之间的关系。方法:蝙蝠葛碱6 mg·kg-1静脉注射后,8 h内定时取血,同时观察并记录心电图变化。采用反相高效液相-紫外法测定血浆中蝙蝠葛碱的浓度。应用3P97程序药动-药效参数估算程序对血药浓度和效应时间数据进行估算。结果:蝙蝠葛碱在犬体内动力学行为符合二房室开放模型,t1/2α=0.049±0.016 h;t1/2β=2.7±0.6 h。蝙蝠葛碱对HR的最大抑制率为(26.4±6.1)％,对PR,QRS,和Q-Tc间期的最大延长率分别为(33.7±10.0)％、(35.6±12.0)％和(25.5±9.4)％。效应滞后于血药浓度10~15 min。药理效应与效应室浓度之间的关系符合sigmoid-Emax模型。结论:以上模型很好地描述了蝙蝠葛碱在犬体内的血药浓度与其对心电图的药理效应之间的关系。     

美托洛尔光学异构体在犬体内的药动学-药效学结合模型

用麻醉犬研究美托洛尔(Met)光学异构体药动学—药效学结合模型。结果表明,ig(+)-Met或(-)-Met后,其药动学符合二室模型,药动学参数V_d/F,CLs/F和AUC在两种Met之间有显著性差异。(+)-Met和(-)-Met的效应和血药浓度关系呈逆时针滞后环。引入效应室理论后,药效和效应室浓度之间的关系符合Sigmoid-E_max模型。应用CAPP软件进行模型拟合,血药浓度的预测值和药效的预测值皆与其实测值较为接近。(+)-Met抑制V_max,dp/dt_max及HR效应的Ce₅₀分别是(-)-Met的3.7,6.8,6.3倍,证实(-)-Met对犬心脏的抑制作用强于(+)-Met。     

卡维地洛人体药动学与药效学结合模型研究

采用间接药效学模型和效应室模型两种药效学模型分别进行卡维地洛药动学与药效学关系研究, 比较两种药效学模型的拟合程度。高效液相色谱法 (荧光) 测定20名健康志愿者单次口服20 mg卡维地洛片后卡维地洛经时血药浓度, 以DAS 2.0实用药动学计算程序计算卡维地洛药动学参数。同时测定给药前后动脉收缩压和舒张压, 计算降压效果。卡维地洛片主要药动学参数t_1/2为 (4.56 ± 2.56) h, C_max为 (46.29 ± 21.07) ng·mL^-1, AUC_0-∞为 (173.76 ± 87.36) ng·mL^-1·h。间接药效模型主要参数K_in为 (0.41 ± 0.31) % h^-1, K_out为 (0.40 ± 0.26) h^-1, IC₅₀为 (24.40 ± 21.10) ng·mL^-1, AUE为 (3.82 ± 1.46) % h。效应室模型主要参数K_e0为 (0.35 ± 0.27) h^-1, EC₅₀为 (24.30 ± 24.30) ng·mL^-1, AUE为 (5.65 ± 2.54) % h。该方法可用于卡维地洛片人体药动学研究。由AIC值可知, 效应室模型可更好的应用于卡维地洛药动学-药效学结合研究。

     

Pharmacokinetic-pharmacodynamic modeling of metoprolol stereoisomers in spontaneously hypertensive rat

研究美托洛尔对映体（＋）Ｍｅｔ和（－）Ｍｅｔ在麻醉自发性高血压大鼠的药物动力学药效学结合模型，比较两种对映体对其心血管系统的作用．方法：反相高效液相法测定血药浓度，生理记录仪观察药效，计算药动学及药动学药效学结合模型参数．结果：血药浓度时间曲线符合二室模型．Ｖｄ在两种Ｍｅｔ之间有显著性差异．药效和效应室浓度间的关系符合ｓｉｇｍｏｉｄＥｍａｘ模型．（＋）Ｍｅｔ抑制Ｖｍａｘ，ｄｐ／ｄｔｍａｘ和ＨＲ的Ｃｓｓ５０皆明显大于（－）Ｍｅｔ．结论：（＋）Ｍｅｔ和（－）Ｍｅｔ在ＳＨＲ存在着立体选择性分布，（－）Ｍｅｔ对其心血管系统的抑制作用强于（＋）Ｍｅｔ．     

环维黄杨星D抗心肌缺血PK-PD结合模型的研究

摘 要 目的： 应用药动学 药效学（PK-PD）结合模型的研究方法考察环维黄杨星D（CVB-D）在心肌缺血家兔体内的药动学和药效学之间的关系。方法: 以冠状动脉结扎方法制备家兔心肌缺血模型,运用微透析采样技术考察CVB-D经皮给药和灌胃给药后在心肌组织内的浓度变化,分时采血检测试验动物血浆中乳酸脱氢酶(LDH)、肌酸激酶(CK)、丙二醛(MDA)活性变化,用药物学软件拟合PK-PD模型,并计算主要参数。结果: 药理效应与药物浓度之间符合抑制性S型最大效应模型,并准确计算出PK-PD结合模型参数。结论: 建立了环维黄杨星D在心肌缺血家兔体内的PK-PD结合模型,得到药动学和药效学参数,Cp-E曲线以及各个药效指标在不同给药途径条件下的量效方程。     

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.