叶酸受体阳性肿瘤细胞对Folate-PGA偶联酶的特异性结合

目的考察叶酸受体阳性肿瘤细胞对叶酸偶联的青霉素G酰化酶(Folate-PGA)的特异性结合。方法采用Iodo-gen法标记的125I-Folate-PGA测定叶酸受体表达阳性FR(+)HeLa与SKOV3细胞以及叶酸受体表达阴性FR(-)A549细胞于4℃对Folate-PGA偶联酶的结合。结果125I-Folate-PGA对FR(-)A549无特异性结合;与HeLa和SK-OV3细胞的特异性结合的Kd分别为0.11nmol·L-1和0.25nmol·L-1。结论叶酸偶联的PGA酶对FR(+)肿瘤细胞具有较好的亲和力和靶向性,可用于叶酸导向的酶前体药物疗法的进一步研究。     

叶酸靶向的PGA联合N-苯乙酰化阿霉素的抗肿瘤活性

目的考察叶酸靶向的青霉素酰化酶G(PGA)联合前药N-苯乙酰化阿霉素(DOXP)对叶酸受体阳性肿瘤细胞的活性。方法通过双功能偶联剂EDC将叶酸与PGA偶联，荧光显微镜观察HeLa和SKOV3细胞对叶酸-PGA的摄取，MTT法检测DOXP联合叶酸-PGA对HeLa和SKOV3细胞的毒性。结果叶酸-PGA能被HeLa和SKOV3细胞选择性摄取；DOXP在叶酸-PGA的作用下对HeLa和SKOV3细胞的IC₅₀分别为0.72和0.75 μmol·L^-1，均低于阿霉素。结论叶酸-PGA的特异性靶向作用提高了阿霉素对HeLa和SKOV3细胞的敏感性。     

叶酸靶向的肿瘤治疗研究进展

叶酸靶向的递药系统是一种新兴的治疗多种恶性肿瘤的方法。利用叶酸分子与肿瘤细胞表面叶酸受体的高亲和力,叶酸偶联的化合物能够将分子大小不同的复合物递送给病理细胞而不对正常组织造成伤害。目前,通过这种方法成功递送到叶酸受体高表达肿瘤细胞的复合物包括:蛋白毒素、化疗药物、免疫治疗剂、基因载体、反义寡核苷酸、小分子干扰RNA和纳米载体。该文综述了多种叶酸作为靶向配体治疗恶性肿瘤的方法。     

用连接叶酸的脂质体增加对体外培养的HeLa细胞的输送

在传代培养的ＨｅＬａ细胞上观察了叶酸对脂质体靶向摄取功能的影响。将内含钙黄绿素的叶酸．脂质体和脂质体分别加入ＨｅＬａ细胞中培养,并以荧光法检测细胞摄取量。共同培养４ｈ,细胞摄取叶酸一脂质体量为脂质体４倍以上,在０．４５ｍｇ·　ｍＬ~（－１）时达饱和;过量游离叶酸竞争抑制细胞对叶酸－脂质体的摄取;磷脂酶Ｄ或磷脂酰肌醇特异性磷脂酶Ｃ通过影响叶酸受体而抑制细胞对叶酸－脂质体的摄取。因此,ＨｅＬａ细胞主要通过叶酸受体途径介导摄取叶酸－脂质体：叶酸受体高表达或高活性细胞摄取叶酸－脂质体的能力较未接叶酸的脂质体显著提高。     

叶酸受体介导的负载紫杉醇纳米药物输送系统的体外生物活性的研究

目的:叶酸受体介导的负载紫杉醇纳米药物输送系统的的体外生物活性研究。方法:应用激光共聚焦观察肝素-叶酸-紫杉醇纳米粒进入叶酸受体阳性表达KB细胞和叶酸受体阴性表达A549细胞的情况,考察纳米粒对靶细胞摄取情况;以原药紫杉醇为对照组,应用MTT法检测纳米粒子对叶酸受体阳性表达KB细胞的抗癌抑制活性;应用流式细胞仪对纳米粒子抗癌机制进行分析。结果:细胞摄取实验表明,肝素-叶酸-紫杉醇纳米药物是通过叶酸受体介导的内吞作用实现对靶细胞的特异性;与紫杉醇对比,纳米粒子的针对叶酸受体阳性细胞的抑制效果更好,半数抑制浓度(IC50)为0.06g/mL,MTT实验结果与细胞摄取实验结果一致;流式细胞仪检测表明肝素-叶酸-紫杉醇纳米药物也表现出与紫杉醇相似的抑制作用,即G2/M期均有所增长。结论:体外生物活性检测表明叶酸受体介导的负载紫杉醇的纳米药物输送系统有较好的靶向性,其应用前景值得期待。     

叶酸受体介导的靶向给药研究进展

叶酸受体可以与叶酸及其类似物特异性结合,通过介导细胞内化将其摄入细胞胞浆。利用叶酸受体在肿瘤和关节炎细胞的过度表达,使药物与叶酸结合,以叶酸受体为作用靶点,即可将药物主动靶向肿瘤和关节炎细胞,从而提高药物在肿瘤、关节炎的组织分布,达到靶向诊断、治疗的目的。本文就叶酸受体及其组织分布,叶酸受体介导的内吞作用,叶酸受体介导的肿瘤和关节炎的靶向诊断、治疗的研究进展进行了综述。     

叶酸受体介导的抗肿瘤药物研究进展

   叶酸受体在大多数人体肿瘤细胞表面过度表达,而在正常细胞中的存在很少,甚至检测不到,这就使叶酸受体介导的抗肿瘤药物可以靶向性地作用于叶酸受体呈阳性的肿瘤细胞,减少传统抗癌药物对正常细胞的毒副作用,提高药物的选择性。本文对叶酸受体介导的抗肿瘤药物的作用机制进行综述,介绍近几年研究者设计并合成的叶酸-药物缀合物及其活性测试的结果。     

以叶酸受体为靶向的阳离子脂质体的制备与性质考察

为了研制一种能通过叶酸受体途径靶向肿瘤细胞的叶酸受体靶向脂质体，将叶酸(folate，folic acid，F)、 聚乙二醇二胺(polyoxyethylene-bis-amine，NH₂-PEG-NH₂)、 琥珀酸酐(succinic anhydride，SUC)和二硬脂酰磷脂酰乙醇胺(distearoylphosphatidylethanolamine，DSPE)按序共价连接， 并使用薄层色谱和飞行时间质谱确证合成产物为叶酸-聚乙二醇-二硬脂酰磷脂酰乙醇胺(folate-polyethyleneglycol-distearoylphosphatidylethanolamine，F-PEG-DSPE)。膜材选用二棕榈酰磷脂酰胆碱(dipalmitoylphosphatidylcholine，DPPC)， 3β-［N-(N′,N′-二甲基胺乙基)胺基甲酰基］胆固醇(3β-［N(N′,N′-dimethylaminoethane) carbamoyl］ cholesterol，DC-Chol)和F-PEG-DSPE，以10∶10∶0.75(摩尔比)的配比，以荧光素标记的阴离子葡聚糖(dextran fluorescein anionic，DFA)为模型，用薄膜分散法制备含DFA的叶酸受体靶向脂质体，其包封率较高(>55%)、稳定性好，平均粒径为144 nm，体外释放慢。MTT法考察其对细胞的毒性结果表明该阳离子脂质体具有一定的细胞毒性，在低浓度时(0.012 5～0.1 μmol·L^{-1)脂质体的细胞毒性与DC-chol浓度成正比。流式细胞技术检测KB细胞和HepG2细胞对DFA脂质体的摄取，结果表明叶酸受体靶向的长循环阳离子脂质体能提高细胞对脂质体的摄取。该研究为进一步研究叶酸受体靶向阳离子脂质体在肿瘤基因治疗中的应用提供了理论基础。}     

叶酸受体介导的靶向纳米给药系统研究进展

叶酸受体在许多恶性肿瘤细胞表面过度表达,而在正常细胞中则几乎不表达或只有少量表达。利用叶酸受体表达的特性,通过将叶酸修饰于药物载体表面,可使药物靶向输送至叶酸受体过度表达的肿瘤细胞中,从而避免对正常细胞产生毒性,提高药物疗效;而纳米给药系统因粒径较小等原因可使药物在肿瘤部位浓集。本文对近年来叶酸受体介导的靶向纳米给药系统进行了综述。     

叶酸受体介导的靶向给药系统研究进展

叶酸受体在多种肿瘤细胞表面过度表达,能与特异性的配体结合并将药物靶向运输到特定的肿瘤细胞。本文介绍了叶酸受体介导的靶向给药系统的作用机制和几种常见的药物载体系统。     

Synthesis,Cytotoxicity and Antileishmanial Activity of Some N-(2-(indol-3-yl)ethyl)-7-chloroquinolin-4-amines

We report herein the condensation of 4,7-dichloroquinoline (1) with tryptamine (2) and D-tryptophan methyl ester (3) . Hydrolysis of the methyl ester adduct (5) yielded the free acid (6) . The compounds were evaluated in vitro for activity against four different species of Leishmania promastigote forms and for cytotoxic activity against Kb and Vero cells. Compound (5) showed good activity against the Leishmania species tested, while all three compounds displayed moderate activity in both Kb and Vero cells.     

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.

     

Lung disease and PKCs

The lung offers a rich opportunity for development of therapeutic strategies focused on isozymes of protein kinase C (PKCs). PKCs are important in many cellular responses in the lung, and existing therapies for pulmonary disorders are inadequate. The lung poses unique challenges as it interfaces with air and blood, contains a pulmonary and systemic circulation, and consists of many cell types. Key structures are bronchial and pulmonary vessels, branching airways, and distal air sacs defined by alveolar walls containing capillaries and interstitial space. The cellular composition of each vessel, airway, and alveolar wall is heterogeneous. Injurious environmental stimuli signal through PKCs and cause a variety of disorders. Edema formation and pulmonary hypertension (PHTN) result from derangements in endothelial, smooth muscle (SM), and/or adventitial fibroblast cell phenotype. Asthma, chronic obstructive pulmonary disease (COPD), and lung cancer are characterized by distinctive pathological changes in airway epithelial, SM, and mucous-generating cells. Acute and chronic pneumonitis and fibrosis occur in the alveolar space and interstitium with type 2 pneumocytes and interstitial fibroblasts/myofibroblasts playing a prominent role. At each site, inflammatory, immune, and vascular progenitor cells contribute to the injury and repair process. Many strategies have been used to investigate PKCs in lung injury. Isolated organ preparations and whole animal studies are powerful approaches especially when genetically engineered mice are used. More analysis of PKC isozymes in normal and diseased human lung tissue and cells is needed to complement this work. Since opposing or counter-regulatory effects of selected PKCs in the same cell or tissue have been found, it may be desirable to target more than one PKC isozyme and potentially in different directions. Because multiple signaling pathways contribute to the key cellular responses important in lung biology, therapeutic strategies targeting PKCs may be more effective if combined with inhibitors of other pathways for additive or synergistic effect. Mechanisms that regulate PKC activity, including phosphorylation and interaction with isozyme-specific binding proteins, are also potential therapeutic targets. Key isotypes of PKC involved in lung pathophysiology are summarized and current and evolving therapeutic approaches to target them are identified.     

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.     

Gender-related symptoms and correlates of alcohol dependence among men and women with a lifetime diagnosis of alcohol use disorders

This study explored gender-related symptoms and correlates of alcohol dependence in a crosssectional study of 150 men and 150 women with a lifetime diagnosis of alcohol use disorders (AUD). Participants were recruited in equal numbers from treatment settings, correctional centres and the general community. Standardized measures were used to determine participants' use of substances, history of psychiatric disorders and psychosocial stress, their sensation seeking and family history of substance use and mental health disorders. Multivariate analyses were used to detect patterns of variables associated with gender and the lifetime severity of AUD. Men had a longer history of severe AUD than women. Women had similar levels of alcohol dependence and medical and psychological sequelae as men, despite 6 fewer years of AUD. More women than men had a history of severe psychosocial stress, severe dependence on other substances and antecedent mental health problems, especially mood and anxiety disorders. There were differences in family history of alcohol-related problems approximating same-gender aggregation. The severity of a lifetime AUD was predicted by its earlier age at onset and the occurrence of other disorders, especially anxiety, among both men and women. The limitations in the generalizability of these findings due to sample idiosyncrasies are discussed.     

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.