栀子大黄汤有效成分在体肠吸收研究

目的：研究栀子大黄汤中栀子苷、柚皮苷、橙皮苷和新橙皮苷4种有效成分的大鼠在体肠吸收动力学。方法：运用大鼠在体单向灌流重量法进行肠吸收实验,考察不同吸收部位和药物浓度下的肠吸收动力学,采用HPLC法测定有效成分的浓度。结果：栀子苷、柚皮苷和新橙皮苷在小肠的吸收速率常数（Ka）和有效渗透系数（Peff）显著大于结肠（P〈0.05）;橙皮苷在十二指肠和空肠吸收参数显著大于回肠和结肠（P〈0.05）;药物浓度在一定范围内对栀子苷、柚皮苷和新橙皮苷的Ka和Peff无显著影响（P〉0.05）,橙皮苷的Ka和Peff随浓度的升高先增加后降低。结论：栀子大黄汤中4种有效成分在全肠道均有吸收;栀子苷、柚皮苷和新橙皮苷的吸收机制为被动扩散,橙皮苷在吸收过程中存在高浓度饱和现象,推测吸收机制为主动转运或易化扩散。     

芒果苷大鼠在体肠道吸收机制研究

目的:研究芒果苷大鼠在体肠道吸收机制。方法:采用大鼠在体肠段灌流模型,建立高效液相色谱/紫外分光光度法测定肠循环液中芒果苷的浓度,研究不同芒果苷浓度、胆汁及吸收部位对芒果苷吸收参数的影响。结果:芒果苷在5.0~25.0μg.mL-1浓度范围内对小肠吸收速率常数(Ka)无影响;在12.5μg.mL-1浓度下对结扎胆管大鼠的小肠Ka有影响;各肠段的Ka回肠>空肠>结肠>十二指肠,分别为0.164、0.132、0.125、0.107h-1。结论:芒果苷的吸收符合一级动力学特征,吸收机制为被动扩散;芒果苷在各肠段均有较好的吸收,胆汁使芒果苷在小肠的透过系数增大。     

绞股蓝总皂苷的大鼠在体肠吸收动力学研究

目的研究绞股蓝总皂苷在大鼠各肠段的吸收动力学特征,为制剂设计提供理论依据。方法采用大鼠在体肠吸收模型和紫外分光光度法研究药物在大鼠各肠段的吸收特性。结果绞股蓝总皂苷在0.17~0.37mg/mL范围内对小肠吸收速率常数Ka无显著性影响;十二指肠、空肠、回肠、结肠各肠段的吸收速率常数Ka无显著性差异。结论绞股蓝总皂苷在大鼠肠道的吸收呈一级动力学过程,为被动扩散,吸收窗较广,可开发成缓释制剂。     

在体肠灌流模型研究灵仙新苷的大鼠肠吸收特性

目的:研究灵仙新苷在大鼠肠段的吸收特征。方法:以酚红为标示物,采用在体单向肠灌流模型,LC-MS/MS测定灵仙新苷在体肠灌流的浓度变化,研究灵仙新苷的吸收部位和吸收动力学特征。结果:灵仙新苷在大鼠小肠各肠段的吸收速率常数(Ka)、有效渗透系数(Peff)是十二指肠>空肠≈回肠,且十二指肠的Ka和Peff值与其他肠段存在显著性差异(P<0.05);灌流液中同一肠段不同浓度灵仙新苷的Ka和Peff均无统计学显著差异;盐酸维拉帕米和环孢素A均显著性降低对灵仙新苷的吸收(P<0.05)。结论:灵仙新苷在小肠有不同程度的吸收,其中在十二指肠吸收最好,药物浓度对灵仙新苷的Peff和Ka值无影响,其吸收机制为被动扩散,灵仙新苷可能不是P-糖蛋白底物。     

单向灌流法评价栀子厚朴汤方剂配伍对栀子苷肠吸收的影响

目的:考察大鼠在体灌流栀子、栀子-枳实、栀子-厚朴和栀子厚朴汤4种汤剂后栀子苷在大鼠肠道吸收情况.方法:建立大鼠在体单向肠灌流模型,应用高效液相色谱法测定大鼠肠灌流液中栀子苷的浓度,计算不同配伍组栀子苷吸收参数.结果:栀子-枳实、栀子-厚朴配伍以及栀子厚朴汤全方中栀子苷的吸收速率常数(Ka)和有效渗透系数(Peff)显著大于栀子单味汤剂的吸收参数(P＜0.05).结论:栀子厚朴汤方剂配伍,增加了主要药效物质栀子苷的吸收,该方剂配伍具有一定合理性.     

胡黄连苦苷Ⅱ大鼠在体肠吸收特征研究

目的 研究胡黄连苦苷Ⅱ在大鼠肠道各区段的吸收动力学特征、吸收部位.方法采用大鼠在体肠循环灌流实验,采用HPLC法对循环液中的胡黄连苦苷Ⅱ进行分析,研究其吸收部位和吸收动力学特征.结果胡黄连苦苷Ⅱ在肠道各部位的吸收速率常数(Ka)和表观渗透系数(Papp)按照空肠、回肠、十二指肠的顺序依次下降.结论胡黄连苦苷Ⅱ在肠道内无...     

香青兰黄酮类化合物的大鼠在体肠吸收

目的:研究香青兰总黄酮在大鼠各肠段的吸收动力学特征。方法:采用大鼠在体肠灌流模型,利用HPLC法测定灌流液中田蓟苷的浓度,研究田蓟苷和香青兰总黄酮在大鼠各肠段的吸收特性。结果:香青兰总黄酮中田蓟苷在大鼠各肠段的吸收速率常数Ka值按结肠、空肠、十二指肠、回肠顺序依次分别为5.7651×10-2,4.4081×10-2,4.3873×10-2,3.9899×10-2;田蓟苷在大鼠各肠段的吸收速率常数Ka值按十二指肠、回肠、空肠、结肠顺序依次分别为6.7897×10-2,6.3018×10-2,5.8011×10-2,5.6765×10-2。结论:田蓟苷单体与香青兰总黄酮中田蓟苷在大鼠各肠段的吸收特征相一致,二者在大鼠小肠段不同部位的吸收均不存在差异。     

芍药苷微乳溶液在大鼠在体肠的吸收动力学研究

目的考察芍药苷微乳溶液在大鼠在体肠吸收动力学特征,并与其水溶液进行比较,研究芍药苷微乳溶液在各肠段的吸收情况。方法采用大鼠在体肠吸收实验方法,用HPLC和UV法分别测定循环液芍药苷和酚红的浓度。结果在2～20mg.L-1浓度范围内芍药苷微乳溶液的吸收量与浓度成线性关系,吸收速率常数(Ka)值基本保持不变,芍药苷微乳溶液吸收药量和Ka均高于其水溶液;各肠段吸收有差异,结肠吸收药量和Ka明显高于十二指肠、空肠和回肠,Ka值依次为(0.501±0.031)、(0.086±0.003)、(0.108±0.017)、(0.114±0.006)h-1。结论芍药苷微乳溶液在肠道的吸收呈一级吸收动力学,吸收机制为被动吸收;芍药苷微乳溶液在空肠和结肠段吸收较好,且在肠道吸收好于芍药苷水溶液。提示可将芍药苷制成微乳制剂,以提高其生物利用度。     

银杏总黄酮苷在大鼠体内的肠吸收动力学特征

目的　考察银杏总黄酮苷(TFG)在大鼠体内的肠吸收动力学特征。方法　对大鼠的十二指肠、空肠、回肠和结肠4个部位分别进行在体肠吸收实验,计算和比较TFG在各部位的吸收速率常数(Ka)和2h的累积吸收量。结果　TFG在大鼠肠道各部位的Ka 按十二指肠、空肠、回肠、结肠依次下降;在10 0～4 0 0mg·L-1浓度范围内,各肠段TFG的吸收量与浓度有良好线性关系(r>0 .994 4 ) ,Ka 值基本不变。结论　TFG在大鼠肠道内的吸收呈现一级吸收动力学特征,其吸收机制为被动扩散     

间尼索地平对映体的大鼠在体肠吸收动力学

建立HPLC-DAD法测定肠循环液中的间尼索地平,探讨S型和R型间尼索地平在大鼠各肠段的吸收动力学特征,考察药物浓度、pH和吐温-80浓度对药物肠吸收的影响.采用大鼠在体小肠回流装置,使用C18色谱柱,以乙腈-1.0%磷酸(62:38)为流动相,检测波长353 nm.结果显示间尼索地平对映体在1～80 μg/ml浓度范围内与吸收量的线性关系良好,吸收速率常数Ka基本保持不变;各肠段的吸收速率无显著性差异.全肠段吸收呈现一级动力学过程,吸收机制为被动扩散.     

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.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

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.