Synthesis and evaluation of 5,7‐dichloro‐4‐(3‐{4‐[4‐(2‐[18F]fluoroethyl)‐piperazin‐1‐yl]‐phenyl}‐ureido)‐1,2,3,4‐tetrahydroquinoline‐2‐carboxylic acid as a potential NMDA ligand to study glutamatergic neurotransmission in vivo

The neurotransmitter glutamate is thought to be crucially involved in a huge number of neurological and psychiatric disorders, such as Morbus Parkinson, Alzheimer's disease and schizophrenia. Aiming at an improved diagnostic tool for PET a new [¹⁸F]fluorine labelled NMDA receptor ligand was developed that may potentially allow the in vivo visualization of glutama‐tergic neurotransmission. The ¹⁹F‐analogue trans‐5,7‐dichloro‐4‐(3‐{4‐[4‐(2‐fluoroethyl)‐piperazin‐1‐yl]‐phenyl}‐ureido)‐1,2,3,4‐tetrahydro quinoline‐2‐carboxylic acid was synthesised to determine the binding affinity, lipophilicity and biodistribution of the ligand. This substance exhibits a K_i of 12 nM for the glycine binding site using [³H]MDL‐105,519 assays on pig cortical membranes. A logD of 1.3 was determined for this compound according to the OECD guidelines employing the HPLC method. Radiosynthesis of this ligand was achieved by labelling the precursor trans‐5,7‐dichloro‐4‐[3‐(4‐piperazin‐1‐yl‐phenyl)‐ureido]‐1,2,3,4‐tetrahydroquinoline‐2‐carboxylic acid methyl ester with 2‐[¹⁸F]fluoroethyltosylate and subsequent cleaving of the methyl ester moiety, resulting in an overall decay corrected yield of 35% of the final product trans‐5,7‐dichloro‐4‐(3‐{4‐[4‐(2‐[¹⁸F]fluoroethyl)‐piperazin‐1‐yl]‐phenyl}‐ureido)‐1,2,3,4‐tetrahydroquinoline‐2‐carboxylic acid. The biodistribution kinetics of this compound were determined with Sprague Dawley rats ex vivo for brain, liver, kidney, and bone. The ligand showed a maximum brain uptake 30 min.p.i. of about 0.1% ID/g. Copyright © 2003 John Wiley & Sons, Ltd.     

端粒酶抑制剂对小鼠胃癌放疗的增敏作用研究

目的：探讨端粒酶抑制剂对动物在体肿瘤的治疗作用及对放射治疗的增敏价值。方法：将SGC-7901胃癌细胞接种BALB/c小鼠，采用端粒酶抑制剂AZT联合放疗治疗小鼠胃癌，观察其对肿瘤体积和肿瘤端粒酶活性的影响。结果：未治疗组小鼠肿瘤体积增加了2.5倍，而AZT组、放疗组及AZT联合放疗组肿瘤体积分别缩小了26.3%、36.8%及70.5%。肿瘤端粒酶活性检测，未治疗组、AZT、放疗均能使肿瘤体积缩小并降低前几天粒酶活性分别为100、55.2、24.5及12.1。结论：AZT放疗均能使肿瘤体积缩小并降低端粒酶活性，且AZT能增加肿瘤的放射敏感性。     

Interaction of topiramate with glycine receptor channels

Glycine receptor channels are pentameric ligand-gated ion channels that respond to the application of inhibitory neurotransmitters by opening of a chloride-selective central pore. Topiramate (TPM) is a broad-spectrum antiepileptic drug used as add-on or monotherapy for focal seizures. In the present study the interaction of TPM with glycine receptor channels was studied on outside-out patches from HEK293 cells expressing alpha1beta glycine receptor channels. The patch clamp techniques combined with ultra fast solution exchange enabled us to investigate the kinetics of receptor channels in presence of TPM. Our study showed no agonistic or potentiating effect for TPM on glycine receptor channels. However, in presence of 1 mM glycine + 1 mM TPM, the desensitization got faster and the peak current amplitude decreased. After the end of glycine + TPM pulses, off-currents occurred, suggestive for a specific channel block mechanism.     

抗HIV药物研究进展及发展趋势

本文分类总结了近年来抗HIV药物的研究进展以及以后的发展趋势,着重介绍了抗HIV的新的作用靶点和天然活性产物在抗HIV方面的应用。     

Antiproliferative activity and standardization of Tecomella undulata bark extract on K562 cells

Ethnopharmacological relevance

The bark of Tecomella undulata is primarily used in the treatment of syphilis, painful swellings and cancer by traditional healers. Also, it is claimed to be useful in treating urinary discharges, enlargement of spleen, leucorrhoea, leukoderma, tumors, liver disorders, gonorrhea, gout and promotes wound healing in Indian traditional system of medicine.

Aim

To establish a scientific validation for the antitumor effects of Tecomella undulata bark and explore the mechanistic pathway in chronic myeloid leukemia cell line, K562. The study was further extended to standardize the extract using quercetin as biomarker.

Methods

Induction of apoptosis by chloroform extract of Tecomella undulata bark (CTUB) was determined by MTT, Annexin V and caspase activation assays. The cell cycle analysis was done by flow cytometer and nuclear staining by DAPI. The standardization of the extract was performed through reverse phase-HPLC method under PDA detection.

Result

Results clearly showed the induction of apoptosis by CTUB in K562 cells. The effect was found to be dose dependent, having IC₅₀ of 30 μg/ml with activation of FAS, FADD, caspase 8, caspase 3/7 and fragmentation of DNA. The bioactive CTUB was determined to possess 0.03% (w/w) of quercetin.

Conclusion

The investigation clearly demonstrated the potential antitumor effect of CTUB, thereby validating the traditional claim. Quercetin, known to have anticancer activity is being reported and quantified for the first time from the bark of Tecomella undulata.     

健脾补肾、和解泄浊法抑制肾间质纤维化的实验研究

目的 观察补肾排毒合剂对单侧输尿管梗阻（UUO）后大鼠肾间质α-平滑肌肌动蛋白（α—SMA）、Ⅳ型胶原（Col Ⅳ）表达的影响及对肾间质纤维化的保护作用。方法 采用UUO诱导肾间质纤维化的动物模型，将48只Wistar大鼠随机分为假手术组（Sham）、模型组（UUO）和补肾排毒合剂治疗组（REM），每组分别于造模后3、10、20、30d各处死4只，取左肾组织行HE染色，动态观察肾脏病理学变化，评定各组肾小管间质损害程度，以免疫组化方法测定肾组织中α—SMA、Col Ⅳ。结果 与UUO组比较，REM组大鼠肾间质病变程度明显减轻，α-SMA、Col Ⅳ在肾间质中的表达也有明显降低。结论 补肾排毒合剂可通过降低α—SMA、Col Ⅳ的表达，减少肾间质细胞外基质合成，延缓肾间质纤维化的进展。     

d-Penicillamine2,5-enkephalin作为底物考察三明治大鼠原代肝细胞的转运体功能研究

目的:通过液相色谱-串联质谱(LC/MS/MS)法测定d-Penicillamine2,5-enkephalin (DP-DPE)在肝细胞和Hank's缓冲液中的浓度,研究DPDPE作为底物用于“三明治”培养大鼠原代肝细胞(SCRH)的转运体功能.方法:将SCRH与溶于Hank's缓冲液的DPDPE共温孵,采用LC/MS/MS法测定细胞内蓄积的和外排到缓冲液中的DPDPE浓度,用于评价模型药物α-萘异硫氰酸酯(ANIT)对参与DPDPE摄取的Oatp和负责DPDPE外排的Mrp2的转运功能的影响.结果:建立的样品处理和测定方法能够满足体外转运实验需要的灵敏度和线性范围,在Hank's缓冲液中线性范围为0.5～50 ng/mL(r2 =0.9995),在细胞基质中线性范围为0.1～5 ng/well(r2=0.9997),样品处理操作简便.日内日间精密度(RSD)均小于15％;提取回收率大于65％.ANIT可抑制DPDPE在SCRH胆管侧的外排及基底侧的摄取,对基底侧外排无显著影响.结论:该分析方法选择性好,灵敏度高,操作简便,并成功地用于将DPDPE作为探针底物研究SCRH模型上转运体的功能.     

肾脏转运体及其研究方法

肾脏是机体重要器官之一,主要承担着体内代谢产物、药物以及毒物等物质的排泄。因此明确各物质在肾脏排泄机制有利于提高药物的安全性,避免不良反应,可为指导临床合理用药提供理论依据。本文介绍了肾脏中介导药物分泌与重吸收的转运体,阐述了通过体内、体外方法预测药物经肾脏转运体在肾脏的转运以及排泄机制。此外,还概括了研究肾脏转运体的主要研究方法,为基础以及临床实验提供参考。     

Structure and function of delta-atracotoxins: lethal neurotoxins targeting the voltage-gated sodium channel.

Delta-atracotoxins (delta-ACTX), isolated from the venom of Australian funnel-web spiders, are responsible for the potentially lethal envenomation syndrome seen following funnel-web spider envenomation. They are 42-residue polypeptides with four disulfides and an "inhibitor cystine-knot" motif with structural but not sequence homology to a variety of other spider and marine snail toxins. Delta-atracotoxins induce spontaneous repetitive firing and prolongation of action potentials resulting in neurotransmitter release from somatic and autonomic nerve endings. This results from a slowing of voltage-gated sodium channel inactivation and a hyperpolarizing shift of the voltage-dependence of activation. This action is due to voltage-dependent binding to neurotoxin receptor site-3 in a similar, but not identical, fashion to scorpion alpha-toxins and sea anemone toxins. Unlike other site-3 neurotoxins, however, delta-ACTX bind with high affinity to both cockroach and mammalian sodium channels but low affinity to locust sodium channels. At present the pharmacophore of delta-ACTX is unknown but is believed to involve a number of basic residues distributed in a topologically similar manner to scorpion alpha-toxins and sea anemone toxins despite distinctly different protein scaffolds. As such, delta-ACTX provide us with specific tools with which to study sodium channel structure and function and determinants for phyla- and tissue-specific actions of neurotoxins interacting with site-3.     

EGCG联合放疗治疗鼻咽癌裸鼠移植瘤模型

目的 研究表没食子儿茶素没食子酸酯(epigallocatechin-3-gallate,EGCG)对鼻咽癌裸鼠移植瘤放疗的增敏效应及survivin和VEGF的表达及意义.方法 体外培养低分化鼻咽癌CNE-2细胞,接种于20只雄性裸鼠皮下,待肿瘤结节约4～6 mm时,随机分为生理盐水组、EGCG组(30 mg/kg)...