胃癌靶向治疗的研究进展

胃癌作为危害人类的常见恶性肿瘤之一,对于胃癌的发病机制及其治疗方案一直是临床研究的关键问题.目前,随着在分子水平上对胃癌一系列恶性生物学行为机制研究的不断深入,分子靶向治疗已成为胃癌领域研究热点.目前胃癌靶向药物研究的热门信号通路包括人类表皮生长因子受体(EGFR)家族信号通路、血管内皮生长因子(VEGF)信号通路等.本文收集国内外近几年相关研究和临床试验报道,对胃癌靶向治疗的研究进展做一简要综述.     

PI3K-Akt-mTOR信号传导通路与乳腺癌关系的研究进展

乳腺癌发病机制复杂,涉及到多条信号通路如丝裂原活化蛋白激酶(Mitogen-activated protein kinase,MAPK)、磷酸肌醇3-激酶(Phosphati-dylinositol 3-kinase,PDK)/蛋白激酶B(PKB,protein kinaseB,Akt)信号通路等的调控。其中PI3K-Akt-mTOR通路成为近年来研究的热点,以此信号通路中的关键分子为靶点的乳腺癌治疗正在研究中。本文对近几年来有关乳腺癌中PI3K-Akt-mTOR信号通路突变和乳腺癌耐药机制的研究及乳腺癌分子靶向治疗等方面作一综述,并对乳腺癌中PI3K-Akt-mTOR信号通路机理研究的意义及新的靶向药物进行展望。     

靶向β-catenin/TCF4相互作用抑制剂在肿瘤分子治疗中的研究进展

经典Wnt信号通路的异常活化与恶性肿瘤的发生与发展密切相关,β-catenin/TCF4 (T-cell factor4)相互作用作为Wnt信号通路中的"分子开关",促进了肿瘤的转移与复发,被认为是广谱高选择性抗肿瘤药物开发的理想靶标之一.目前,PKF222-815、iCRT3/5/14、LF3和血根碱等靶向β-cat...     

Wnt/β-catenin信号通路抑制剂的抗肿瘤研究进展

Wnt信号通路广泛存在于多细胞真核生物中,并且高度保守,在胚胎发育过程中起到重要作用。大量研究表明,Wnt信号通路的异常激活与肿瘤的发生发展密切相关,其在多种恶性肿瘤的增殖、分化、凋亡、迁移、侵袭、上皮间质转化(Epithelial-mesenchymal transition, EMT)及肿瘤干细胞特性中发挥重要作用,因此开发靶向Wnt信号通路的抗肿瘤药物具有重要意义。目前,Wnt信号通路抑制剂的研究已取得一定进展。本文主要对近年来Wnt途径中关键成员Wnt/β-catenin信号通路的抑制剂在肿瘤治疗中的研究进展作一综述。     

抗肿瘤药物Raf激酶抑制剂的研究进展

随着分子生物学的发展,对基于肿瘤分子机制研究的肿瘤分子靶向治疗的研究已获重大进展。蛋白激酶抑制剂是目前肿瘤靶向治疗药物研究的重点之一,通过阻碍细胞内分子传导通路,影响肿瘤细胞的存活、增殖以及疾病进展。在Raf/MEK/ERK信号传导通路中,Raf激酶发挥着至关重要的作用,Raf激酶的突变能使ERK通路保持激活状态,这最终导致细胞的增殖和分化。本综述将阐述Raf激酶在正常与肿瘤细胞中的功能并重点关注于近期发表的各种类型Raf激酶抑制剂。     

木犀草素抗肿瘤血管生成作用机制的研究进展

血管生成是恶性肿瘤的标志之一,涉及血管内皮细胞的增殖、迁移和细胞外基质分解等多种途径。血管内皮生长因子（VEGF）靶向抗肿瘤血管生成是临床肿瘤治疗的有效方法。木犀草素为黄酮类化合物,具有抗肿瘤活性,可通过抑制VEGF及相关信号通路、抑制磷脂酰肌醇3-激酶/蛋白激酶B(PI3K/Akt)信号通路、抑制血管新生分子、抑制孕激素活性、靶向刺激Wnt信号通路、阻断生长停滞特异性蛋白6(Gas6)/受体酪氨酸激酶（Axl）信号通路而发挥抗肿瘤的血管生成作用。归纳了木犀草素抗肿瘤血管生成的作用机制,以期为木犀草素的临床应用提供参考。     

肺腺癌驱动基因的临床研究与进展

肺癌(lung cancer)是全球死亡率最高的恶性肿瘤之一,严重危害人类的健康。目前,肺癌,尤其是肺腺癌的发生发展与诸多驱动基因之间的关系都已受到了众多学者的认可。随着细胞信号传导通路研究的深入,近几年出现了大量针对信号传导通路中不同靶点的靶向治疗药物。本文总结现有相关临床研究,综述多种驱动基因在肺腺癌发生发展过程中的作用机制。同时,汇总基于有效分子标记物的前瞻性临床试验,来评估多种分子靶向药物的疗效,并对未来的靶向治疗做出展望。     

交叉对话信号的分子绝缘——对创新药物设计的思考

生物信号通路的交叉对话(cross-talk)是指众多信号通路共享同一关键组分,形成一种蝴蝶领结(bow-tie)样的网络拓扑结构。交叉对话对终末基因的调节表现出功能冗余、协同及拮抗,同时又要避免通路之间互相串扰带来的信号噪音或信号溢出,进化出一套维持细胞对不同外界应激产生特异性应答的绝缘(insulation)机制,对维持细胞内稳态有着非常重要的生物学意义。交叉对话及其分子绝缘机制提示:对话分子对细胞命运调控的两重性,要求实现靶向对治疗有利的对话分子而避开对治疗不利的对话分子;对话分子以大分子复合物为功能载体,在信号绝缘中对话分子互作界面构象的高度可塑性,设计开展药物结合与药理活性关联性研究。因此,以信号通路的交叉对话及其分子绝缘机制指导创新药物设计,对解决当前药物研发的瓶颈和临床困境具有重大的指导意义。     

靶向程序性死亡分子1信号通路的单克隆抗体的研究进展

程序性死亡分子1 (programmed death-1,PD-1),1种T细胞表面的免疫抑制分子,可与程序性死亡配体1 (programmed death ligand-1,PD-L1)组成信号通路.PD-1/PD-L1信号通路可抑制T细胞活化,并对肿瘤免疫逃逸起关键作用.靶向PD-1信号通路的单克隆抗体包括抗PD-1和PD-L1抗体,它们通过阻断PD-1与PD-L1的相互作用来增强机体内源性抗肿瘤免疫效应,在临床试验中,该类单克隆抗体在各类肿瘤患者中表现出令人惊喜的疗效,成为一类有希望的肿瘤免疫治疗药物.此文就靶向PD-1信号通路的单克隆抗体的生物学功能及其临床应用等方面的研究进展做一综述.     

PD-1/PD-L1信号通路抗肿瘤抑制剂的研究进展

程序性细胞死亡受体1(programmed death 1,PD-1)及其配体(programmed death ligand 1,PD-L1)通路在许多实体瘤中过度激活,有助于肿瘤细胞免疫逃逸,所以阻断PD-1和PD-L1信号通路是恢复肿瘤特异性T细胞免疫能力从而治疗肿瘤的一个有效策略。目前,已有抗PD-1/PD-L1信号通路单克隆抗体药物上市,用于非小细胞肺癌、膀胱癌、三阴性乳腺癌及黑色素瘤等实体瘤的治疗。除了抗体药物外,靶向PD-1/PD-L1信号通路的肽类以及小分子抗癌药物也已成为研究热点。本文对近年来PD-1/PD-L1信号通路抑制剂在肿瘤治疗中的研究现状及进展进行总结。     

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.