肝动脉栓塞微球的研究

本文用乳化聚合法制备了明胶和聚乙烯醇两种微球,通过正交试验,确定了制备特定粒径微球的最佳工艺条件。以氟脲嘧啶和甲氨喋呤为模型药物,对明胶微球的体外溶出特性进行了探讨,结果表明,经复合交联能延缓药物的体外溶出。实验狗灌注微球前后的肝动脉造影表明术后肝动脉分枝有不同程度的减少;病理检查表明微球沉积于肝血窦前的肌性小动脉;γ-射线扫描也证实锝标记微球在肝内的特异性分布。     

靶向给药系统——甲氨蝶呤肝动脉栓塞微球特征及其对大鼠肝癌的实验治疗

本文介绍用乳化—冻凝技术制备甲氨蝶吟—明胶微球的方法。实验结果证实,包裹在微球内的MTX对⁶⁰钻幅射、温度和光照射是稳定的。微球的体外溶出试验、明胶微球在介质中不同时间的溶胀度试验也在文中介绍。微球肝动脉栓塞实验治疗用大鼠移植性肝癌进行,结果表明MTX微球治疗组的大鼠在肿瘤抑制率、促使肿瘤坏死程度以及延长荷瘤动物存活期方面比肝动脉灌注生理盐水、MTX溶液和明胶微球为佳.由于MTX微球具有阻断肿瘤血供和在其局部缓释化疗药物等双重功用,故治疗肝癌的效果明显优于动脉化疗或单纯栓塞方法。     

靶向给药系统——甲氨蝶呤肝动脉栓塞微球特征及其对大鼠肝癌的实验治疗

本文介绍用乳化—冻凝技术制备甲氨蝶吟—明胶微球的方法。实验结果证实,包裹在微球内的MTX对~(60)钻幅射、温度和光照射是稳定的。微球的体外溶出试验、明胶微球在介质中不同时间的溶胀度试验也在文中介绍。微球肝动脉栓塞实验治疗用大鼠移植性肝癌进行,结果表明MTX微球治疗组的大鼠在肿瘤抑制率、促使肿瘤坏死程度以及延长荷瘤动物存活期方面比肝动脉灌注生理盐水、MTX溶液和明胶微球为佳.由于MTX微球具有阻断肿瘤血供和在其局部缓释化疗药物等双重功用,故治疗肝癌的效果明显优于动脉化疗或单纯栓塞方法。     

关节腔内注射用氟比洛芬明胶微球

目的:制备关节腔注射用氟比洛芬明胶微球。方法:按均匀设计法筛选乳化冻凝法制备氟比洛芬明胶微球(FP GMS)的最佳制备工艺。结果:微球粒径范围为2.5～12.3μm,平均粒径为7.53μm,氟比洛芬含量为5.02%(w/w)。其体外释药符合Higuchi方程,稳定性实验表明,FP-GMS的稳定性良好,兔关节腔内注射后,与溶液剂对照组相比氟比洛芬体内平均驻留时间(MRT)显著延长(P<0.01),峰时比对照组延长2.03倍,峰浓度比对照组减小5.57倍。体内外相关性研究表明,FP-GMS体外累积溶出百分率与兔体内药物吸收分数呈显著相关(P<0.01)。结论:本法制备的氟比洛芬明胶微球粒径分布集中,粒径大小符合设计要求,体内外释药结果表明氟比洛芬明胶微球具有明显的缓释作用。     

丹皮酚明胶微球的制备及质量评价

目的 制备丹皮酚明胶微球并进行药剂学性质考察.方法 以丹皮酚为芯材,明胶为载体,采用交联固化法制备丹皮酚明胶微球;采用正交试验优选制备工艺,并对制得的明胶微球进行体外释药性能考察.结果 影响明胶微球包封率的主要因素为明胶浓度和搅拌速度.制得的明胶微球平均粒径100 μm,载药量和包封率分别为8.49%和86.4%,体外释药试验表明所得微球具有明显的缓释作用.结论 所选工艺可用于制备丹皮酚明胶微球,可为缓释药物传递系统提供参考.     

糖皮质激素缓释微球的制备与性质

目的:制备糖皮质激素微球,探讨工艺条件对成球的影响,并测定微球粒径及体外药物溶出度、药物释放时间等性质.方法:以胶原、壳聚糖、明胶等3种天然生物高分子作材料,采用复乳-交联法制备糖皮质激素微球,用显微镜和扫描电镜观察微球形态和粒径分布.模拟探讨糖皮质激素微球的药物释放行为,用反相高效液相色谱法(HPLC)测定微球释放出的药物浓度.结果:按本工艺制作的微球,有90.8%粒径在20～100μm范围内,平均粒径66.6μm,大小适中,体外模拟实验表明,经过7d,药物溶出率约为51.7%～67.8%,与释放介质的pH值相关,具有较好的缓释性能.结论:该缓释体系有望作为新型的糖皮质激素药物新剂型.     

阿霉素磁性明胶微球的研究

报告了阿霉素磁性明胶微球（Ａｄｒ－ＭＧ－ｍｓ）的制备与性质，研究了超细氧化铁粒子的合成和磁性明胶微球（ＭＧ－ｍｓ）在狗体内的栓塞效果。阿霉素磁性明胶微球由２％阿霉素（Ａｄｒ）、６８％明胶和３０％的磁铁粒子组成，微球的平均粒径为２２μｍ。在体外实验中，药物释放速度证明微球有缓释的性质。磁铁粒子的平均粒径约为１０ｎｍ，磁性明胶微球与￣（９９ｍ）Ｔｃ标记磁性明胶微球通过导管分别输入狗的肝动脉内进行栓塞，照相和血管造影显示在未加外磁场时磁性明胶微球在左右肝叶分布几乎相等，而在１２００高斯的外磁场作用下，靶部位肝左叶的微球分布是肝右叶的２．２５倍，而甲状腺、脑、心脏的微球很微量，结果表明磁性明胶微球在外磁场作用下是一个很好的治疗肝癌的栓塞剂。     

肝动脉栓塞用莪术油明胶微球的体外释放的研究

采用连续流动系法对肝动脉栓塞用莪术油明胶微球的体外特性进行了研究,结果表明不同的流速、介质、交联剂用量及交联时间和微球的粒径均对体外释放有影响,但灭菌对微球的体外释放无影响。12小时后,释放80％的药物。药物从微球中的释放符合一级动力学模型,释放机制为溶蚀加扩散。     

动物肝动脉栓塞甲氨蝶呤明胶微球的药动学

本文报道了犬肝动脉灌注甲氨蝶呤（ＭＴＸ）明胶微球后的血药浓度变化，以及大鼠肝动脉灌注１２５Ｉ－ＭＴＸ明胶微球后的体内分布，结果表明，动物肝动脉灌注ＭＴＸ明效微球后，微球主要集中在肝区，且缓慢释放药物。     

肝动脉栓塞用顺铂白蛋白微球的研究

按正交设计筛选乳化热固化法制备顺铂白蛋白微球的最佳工艺,并对影响微球粒径大小和体外释药速率的诸多因素进行了研究。该微球粒径范围为50.8～256μm。平均粒径为148.46μm,药物含量为51.16%(W/W)。兔肝动脉栓塞后,与对照组相比铂的分布半衰期延长336%,消除半衰期延长123%,体内最高血浓仅为对照组的30%。肝组织顺铂量显著增加(P<0.01),肾组织药物量明显降低(P<0.05),体内外相关性研究表明顺铂白蛋白微球体外累积溶出百分率与兔体内药物吸收分数呈显著相关(P<0.01)。     

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.