七叶皂苷A的大鼠血浆蛋白结合率研究

目的 研究七叶皂苷A的大鼠血浆蛋白结合率。方法 在体外用平衡透析法模拟七叶皂苷A体内与血浆蛋白结合的过程,用高效液相色谱-质谱联用(HPLC-MS/MS)法测定低、中、高3个浓度的七叶皂苷A及其转化产物七叶皂苷C在透析袋内血浆中和透析袋外缓冲液中的浓度,计算七叶皂苷A的血浆蛋白结合率。结果 低、中、高3个浓度的七叶皂苷A在体外与大鼠的平均血浆蛋白结合率分别为95.8%,96.6%和95.9%,3个浓度之间的血浆蛋白结合率比较差异无统计学意义(P>0.05)。结论 七叶皂苷A与大鼠血浆蛋白高度结合。     

大黄5个蒽醌类成分与大鼠血浆蛋白结合率的测定

目的建立测定大黄苷元中芦荟大黄素、大黄酸、大黄素、大黄酚、大黄素甲醚5种成分与大鼠血浆蛋白结合率的方法。方法采用体外平衡透析法,模拟大黄苷元与血浆蛋白的结合过程,以固相萃取柱处理血浆样品,用高效液相色谱法测定大黄苷元中5种蒽醌类成分在透析袋内血浆中的浓度与透析袋外缓冲液中的浓度,计算血浆蛋白结合率。结果芦荟大黄素、大黄酸、大黄素、大黄酚、大黄素甲醚提取回收率分别为68.6%,91.5%,78.6%,88.2%和71.4%,与大鼠体外血浆蛋白结合率分别为93.1%,91.3%,95.2%,87.5%和89.7%。结论大黄5种苷元与大鼠血浆蛋白结合率较高,且蛋白结合率与血药浓度无明显依赖性。     

平衡透析法测定具栖冬青苷和毛冬青酸的大鼠血浆蛋白结合率

目的建立测定具栖冬青苷、毛冬青酸血药质量浓度的方法,并测定其大鼠体外血浆蛋白结合率。方法采用高效液相色谱法和平衡透析法测定具栖冬青苷、毛冬青酸在大鼠体外血浆中的血浆蛋白结合率。结果低、中、高3种质量浓度,具栖冬青苷在大鼠体外血浆中的蛋白结合率分别为39.72%±2.68%,52.05%±3.35%和52.32%±0.76%;毛冬青酸在大鼠体外血浆中的蛋白结合率分别为55.18%±3.66%,60.79%±2.20%和47.00%±1.59%。结论建立HPLC法对具栖冬青苷和毛冬青酸进行分离,方法简便。体外实验,具栖冬青苷和毛冬青酸与大鼠血浆属中等结合型药物,且蛋白结合率与药物质量浓度无关。     

荆芥内酯大鼠血浆蛋白结合率的测定

目的:研究荆芥内酯与大鼠血浆蛋白的结合情况。方法:采用平衡透析法测定体外荆芥内酯对大鼠血浆蛋白的结合率,以HPLC法测定透析袋两侧溶液中荆芥内酯的质量浓度,计算其血浆蛋白结合率。结果:荆芥内酯与内标完全分离,血浆中其他成分无干扰,在0.05～50.3μg.mL-1浓度范围内线性关系良好。日内、日间精密度及提取回收率均符合方法学要求。低、中、高(0.08,0.63,6.30μg.mL-1)质量浓度下,荆芥内酯在大鼠血浆中的蛋白结合率分别为(62.23±1.25)%,(62.71±0.04)%和(63.99±0.79)%。结论:该方法操作简便、快速、准确,灵敏度高,能满足生物样品的分析要求。荆芥内酯具有中等强度的蛋白结合率,蛋白结合率与透析液的药物浓度无关。     

黄芩提取物中黄酮类成分血浆蛋白结合率的测定

目的建立同时测定黄芩总黄酮部位中4种黄酮类成分在大鼠血浆中药物浓度的方法,并测定其体外血浆蛋白结合率。方法平衡透析法测定黄芩黄酮类成分血浆蛋白结合率,以高丽槐素为内标,生物样本用甲醇沉淀蛋白进行预处理,采用HPLC法测定4种黄酮类成分在透析内、外液中的浓度。结果在低、中、高3种浓度下,黄芩苷(BL)和汉黄芩苷(WL)的血浆蛋白质结合率随给药浓度的增大而降低(BL:82.03%→77.25%→67.17%;WL:82.24%→76.08%→69.87%),而汉黄芩素(W)和千层纸素A(OA)则呈现非质量浓度依赖性,其平均血浆蛋白结合率分别为(89.66±1.19)%、(88.56±1.87)%。结论该文所建立的测定方法简便、灵敏、专属性强。4个黄酮类成分在大鼠体外均有较高的血浆蛋白结合率。     

平衡透析法结合LC-MS/MS研究奥克梯隆型皂苷元的大鼠血浆蛋白结合率

目的研究奥克梯隆型皂苷元奥克梯隆(ocotillol)的大鼠血浆蛋白结合率。方法采用甲醇沉淀蛋白法对大鼠血浆和磷酸盐缓冲液中的待测物ocotillol和内标人参三醇(PT)进行提取,色谱分离采用Gemini C18柱(50 mm×4.6 mm,3μm),以0.1%甲酸水溶液和0.1%甲酸乙腈溶液为流动相进行梯度洗脱;质谱检测采用电喷雾(ESI)离子源,正离子多反应监测模式(MRM)。并根据FDA指导原则从专属性、线性、定量下限(LLOQ)、准确度、精密度、提取回收率、基质效应以及稳定性等方面进行系统的方法学验证。以平衡透析法为基础,通过建立的液相色谱串联质谱(LC-MS/MS)法测定平衡后透析袋内血浆和透析袋外缓冲液中的ocotillol浓度,计算血浆蛋白结合率。结果 LC-MS/MS法测定ocotillol的线性关系良好(r≥0.995),质控样品的日内、日间精密度(RSD)均<11.68%、提取回收率较高且可重现,无明显的基质效应,样品在室温放置12 h、反复冻融三次、-80℃放置20 d以及处理后自动进样器放置24 h等条件下均能保持稳定。Ocotillol在低、中、高3个浓度下与大鼠的平均血浆蛋白结合率为(84.55±1.69)%,且3个浓度间的血浆蛋白结合率数据无显著性差异。结论 Ocotillol与大鼠血浆蛋白有较强的结合作用。     

冬凌草甲素在不同种属血浆中蛋白结合率的HPLC法测定

目的:建立冬凌草甲素在大鼠血浆、人血浆和牛血清白蛋白中蛋白结合率的测定方法,并计算不同种属血浆蛋白的相关参数。方法:采用HPLC法测定血浆中药物总浓度及游离药物浓度,应用平衡透析法测定蛋白结合率。结果:大鼠血浆中冬凌草甲素高、中、低3个浓度的血浆蛋白结合率分别为(69.66±12.8)%,(59.62±12.6)%,(57.94±4.1)%;人血浆中冬凌草甲素高、中、低3个浓度的血浆蛋白结合率分别为(78.15±3.6)%,(77.92±8.8)%,(76.72±7.3)%;牛血清白蛋白中冬凌草甲素高、中、低3个浓度的血浆蛋白结合率分别为(35.58±7.2)%,(34.59±10.8)%,(32.03±6.0)%。结论:在体外冬凌草甲素与大鼠血浆、人血浆和牛血清白蛋白属中等结合型药物,且蛋白结合率随着药物血浆浓度的增加无明显的浓度依赖性。     

白藜芦醇衍生物RT-B与大鼠血浆蛋白结合率的测定

目的建立测定白藜芦醇衍生物RT—B与大鼠血浆蛋白结合率的方法。方法采用平衡透析法对RT-B与大鼠血浆蛋白结合率进行HPLC测定。结果低、中、高3种浓度下,RT-B的血浆蛋白结合率分别为(79.2±s 0.7)%,(80.1±0.9)%和(80.2±0.9)%。结论本方法灵敏度高,重现性好,操作简单,能满足分析要求。RT-B与大鼠血浆蛋白的结合率较高。     

葡萄内酯大鼠血浆蛋白结合率的测定

目的:建立大鼠血浆中葡萄内酯的检测方法,测定葡萄内酯与大鼠血浆蛋白的结合率。方法:采用平衡透析法研究葡萄内酯在大鼠体内与血浆蛋白结合率。利用醋酸乙酯萃取富集袋内外样品中的葡萄内酯,并用HPLC法测定其浓度,进而求出血浆蛋白结合率。结果:在低、中、高3种浓度下,葡萄内酯的血浆蛋白结合率分别为100.0%、(99.7±0.6)%、(99.1±0.8)%。结论:葡萄内酯溶液与大鼠血浆蛋白属高度结合。     

黄葵胶囊中3种成分与人血浆蛋白结合率的测定

目的 研究黄葵胶囊中芦丁、金丝桃苷和异槲皮苷与人血浆蛋白的结合率.方法 采用平衡透析法测定芦丁、金丝桃苷和异槲皮苷与人血浆蛋白的结合率,用HPLC测定透析内、外液中3种成分的质量浓度,计算血浆蛋白结合率.结果 芦丁、金丝桃和异槲皮苷的线性关系、精密度、提取回收率和稳定性均符合方法学要求;黄葵胶囊低、中、高(1、2、4 mg·mL-1)浓度中,芦丁与人血浆蛋白的结合率分别为58.58％±1.40％、61.83％±2.19％、57.17％±5.48％,金丝桃苷的为79.90％±0.22％、76.96％±0.54％、71.61％±1.76％,异槲皮苷的为80.69％±0.23％、78.10％±0.60％、72.57％±1.86％.结论 黄葵胶囊中3种成分与人血浆具有中等强度的蛋白结合率.     

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.