人口服富硒酵母的药物动力学研究

用金膜电极微分阳极溶出伏安法测定人口服富硒酵母(SEY)后的血浆硒浓度,并用一室模型分析 SEY 在健康人体内的药物动力学参数:半衰期(t_(1/2))3.50 h,吸收速度常数(k_a)0.57h~(-1),消除速度常数(k)0.20h~(-1),药物达峰时间(T_(max))3.39 h,血药浓度-时间曲线下面积(AUC_(0→∞))600 ng/(ml·h)。实验结果显示健康人口服 SEY 10 μgSe/kg 后12 h 从体内基本消除,24 h 后体内完全消除,故在低硒地区按推荐剂量补硒不易引起蓄积中毒。     

抽脂患者皮下注射利多卡因血清与唾液浓度的相关性及其药代动力学研究

本文利用高效液相色谱法对12名抽脂健康患者皮下注射利多卡因的血清、唾液及脂肪浓度进行了测定,探讨了血清与唾液中药物浓度的相关性,并比较了二者之间的药代动力学参数。患者的平均给药剂量为20mg/kg,单剂量给药。实验结果表明血清与唾液中药物浓度呈线性关系:r=0.8043(p<0.01),C_(血清)=0.3433C_(唾液)+0.2620(n=78).唾液与血清药物浓度比值为2.37±0.857(比值范围:1.02～4.09,n=78).测得血清及唾液药代动力学参数分别为:吸收速率常数(Ka)0.573±0.583h~(-1),0.478±0.270h~(-1);消除半衰期(t_(1/2)k)6.41±2.08h,5.68±1.76h;达峰时间(T_(max))6.63±1.46h,6.67±1.80h;峰浓度(C_(max))2.52±0.926μg/ml,6.31±2.30μg/ml.血清与唾液的动力学参数除峰浓度(C_(max))外,统计学上均无明显差异(P>0.05).患者被抽出脂肪的药物含量为给药总量的31.84%(20.69～47.90%).     

老年大鼠的慢性硒中毒

目的　探讨老年大鼠对硒的耐受剂量 ,并比较有机硒 (富硒平菇 )与亚硒酸钠的优劣。方法　在正常饲料的基础上 ,分别加亚硒酸钠、普通平菇干粉、富硒平菇干粉配成含硒量为 0 9、0 3、0 2、0 172mg/kg混合饲料 ,对 18个月龄的Wistar大鼠进行实验 ,实验期 10 2d。观察实验前后体重变化、生存时间、谷胱甘肽过氧化物酶(GSH PX)活性、血红蛋白 (Hb)含量、丙氨酸转氨酶 (ALT)活性、尿素氮 (BUN)含量以及脂质过氧化物 (LPO)含量和超氧化物歧化酶 (SOD)活性。结果　①亚硒酸钠 0 9mg/kg组GSH PX活性随喂养时间延长活性降低、富硒平菇 0 9、0 3mg/kg两组均随时间延长而活性增加。②雄、雌性大鼠在实验前后体重有显著变化 ,雄性减重、雌性增重。③富硒平菇和亚硒酸钠 0 9mg/kg两组生存时间均有降低。④亚硒酸钠 0 9mg/kg组Hb含量降低、ALT活性增高。⑤普通平菇组Hb含量有所增高。⑥富硒平菇 0 3mg/kg组LPO含量降低。结论　亚硒酸钠 0 9mg/kg饲料长时间补充对老年鼠有毒害作用。而适量硒的补充 ,特别是富硒平菇适量硒剂量的补充则有益     

富硒酵母药代动力学研究

<正> 富硒酵母(Selenium Enriched Yeast,SEY)是一种含硒量较高的酵母,其中的硒以自然硒的形式存在,易被机体吸收利用毒性较亚硒酸钠小,故更适宜低硒地区的人体补硒。本文着重报道用金膜电极微分阳极溶出伏安法测定SEY在人体内血药浓度及其药物动力学参数。     

富硒平菇和亚硒酸钠对老年大鼠有关指标的影响

目的　探讨有关硒对老年大鼠 (18月龄 )凝血和纤溶功能有关指标的影响以及富硒平菇和亚硒酸钠对老年鼠合适的补充剂量 ,并比较富硒平菇和亚硒酸钠的优劣。方法　对 18月龄老年鼠进行实验 ,实验期12 3d ,分别观察添加亚硒酸钠或富硒平菇干粉的饲料 (含硒量为 0 2、0 2 5、0 4、0 6mg/kg)对血浆血栓素、前列环素、D 二聚体 (DD)、谷胱甘肽过氧化酶 (GSH PX)、超氧化物歧化酶 (SOD)、脂质过氧化物 (LPO)以及丙氨酸转氨酶(ALT)和实验前后体重变化的差异。结果　适量硒 0 2mg/kg饲料 ,补硒 0 4mg/kg饲料 ,对于老年大鼠前列环素 (PGI2 )含量的增高有促进作用 ,对血栓素A2 (TXA2 )有降低作用 ,对于PGI2 /TXA2 的比值和GSH PX活性的提高及LPO的降低均有促进作用。 0 6mg/kg饲料不能降低PGI2 /TXA2 的比值 ,并能造成D D含量增高和ALT活性有所提高 ,0 6mg/kg饲料组亚硒酸钠还能引起老年鼠体重下降 ,结果还提示富硒平菇优于亚硒酸钠。 结论　补硒应当慎重。     

有机硒富硒麦芽与无机硒亚硝酸钠的毒性比较

目前我国缺硒地区解决硒营养不足问题,是采用口服无机亚硒酸钠片或食用亚硒酸钠强化食盐。然而不少研究表明,有机硒的活性比无机硒高。能更有效地在体内同化,且毒性小。北京市食品工业研究所研制的富硒麦芽,其有机硒的含量达97％以上。与美国研制的硒酵母相比,富硒麦芽还含有一定量的维生素E(V_E)和维生素C(V_C)     

蒿甲醚在兔体内的药代动力学

本文报道蒿甲醚在兔体内的药代动力学。静脉输注蒿甲醚脂肪乳剂(蒿甲醚80mg/kg)后,血药时间数据用NONLIN程序拟合曲线,符合线性二室开模型。药代动力学参数的平均(SD)为:t1/2(α和β)分别为0.144(0.077)h和0.896(0.371)h;k_(2t),k_(10)和k_(12)分别为1.235(0.705),4.143(1.370)和1.140(0.951)h~(-1);V_c,V_d(area)和V_(d(ss))分别为0.609(0.119),2.985(0.787)和1.054(0.202)L/kg;清除率为2.401(0.339)L·kg~(-1)·h。 肌内注射油剂250mg/kg或125mg/kg,血药时间数据按矩量法计算,得吸收速率常数(Ka)为0.0377(0.0119)h~(-1);吸收程度为36.14(18.39)％。     

亚硒酸钠联合泼尼松治疗亚急性甲状腺炎临床观察

目的:探讨亚硒酸钠联合泼尼松对亚急性甲状腺炎患者的影响.方法:对2004年9月-2008年8月在本院诊治的78例亚甲炎患者进行随机对照前瞻性研究.对照组有2例失访,37例完成观察,治疗组39例.两组均予以泼尼松治疗(30 mg/d),治疗组加服亚硒酸钠,总疗程8周左右.结果:经过8周治疗,第2、4周亚硒酸钠组的血沉低于对照组(P＜0.05),亚硒酸钠组2 h、6 h和24 h吸碘率的高于对照组(P＜0.01),而复发率低于对照组(P＜0.05).结论:亚硒酸钠可以缩短亚急性甲状腺炎病程,减少复发率.     

让合理、安全用药知识走进千家万户(四十)

正(接上期)科学补硒方法是:A、人工补硒:摄取人工添加的各类补硒产品主要分为无机硒和有机硒两类,无机硒主要为亚硒酸钠,国外多用于饲料使用,有很大的毒素,已处于淘汰的边缘。有机硒与亚硒酸钠等无机硒相比,具有食用安全、无毒副作用、吸收利用率高、营养价值高等优点。有机硒的种类很多,如硒酵母、硒蛋、富硒藻类、富硒蘑菇和硒麦芽等,其中麦芽硒是目前有机硒发展的最高阶段,比     

用小鼠急性死亡率法测定山莨菪碱的表观药动学参数

用小白鼠急性死亡率法测定了山莨菪碱ip时的经时过程和药动学参数。山莨菪碱在小鼠体内的经时过程为二室开放模型,1.5h之前为分布相,1.5h之后为消除相。用最小二乘法和残余量法求得α、β、A和B四项表现动力学参数分别为3.608h~(-1),0.238h~(-1),529mg/kg(200.2％)和 95mg/kg(35.9％);按药动学公式分别求得分布相表观半寿期(t_(1/2)α)和消除相表现半寿期(t_(1/2)β)为0.2h和2.9h,表观转运速率常数k_(12),k_(21)和k_(10)分别为1.952h~(-1),0.749h~(-1)和1.144h~(-1);表观曲线下面积(AUC)是546mg.h/kg;表观清除率(CI)是0.48kg/(kg.h),表观分布容积V_c,V_p,V_t,和V_b分别为0.42kg/kg,1.10kg/kg,1.53kg/kg和2.04kg/kg.     

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.