应用3H-TdR掺入法对SMMC-7721细胞株药敏试验条件的探讨与应用

目的探讨3H-TdR掺入法在进行SMMC-7721系细胞肿瘤药敏试验实验时的最佳实验条件.方法确定出3H-TdR掺入法药敏实验时的最适细胞浓度、最适实验药物浓度、3H-TdR掺入最适时间;在最适条件下采用3H-TdR掺入法测定肝癌SMMC-7721细胞株对临床常用的9种抗癌药物的敏感性.结果应用3H-TdR掺入法检测肝癌SMMC-7721细胞株药敏试验的最适实验细胞浓度为1×104个/孔,最适试验药物浓度为1×PPC,3H-TdR最适掺入时间为收集细胞前8 h;肝癌SMMC-7721细胞株对DDP、ADM、5-FU、CPT高度敏感,对MTX、VP-16、MMC、NVB低度敏感,对PYM不敏感.结论 3H-TdR掺入法可用于肿瘤药物敏感性测定并确定出它的最适实验条件.     

门静脉化疗对合并癌栓的原发性肝癌术后复发的预防作用

目的　探讨门静脉导管保留术并根据体外肿瘤药敏试验定期行门静脉化疗对合并门静脉癌栓的原发性肝癌术后复发的预防作用。方法　术前经B型超声或CT证实有门静脉癌栓的原发性肝癌病人 6 2例随机分成对照组 (2 9例 )和治疗组 (33例 )。治疗组在肝癌联同门脉癌栓切除术中常规行门静导管保留术 ,术后根据体外肿瘤药物敏感性试验选用敏感性化疗药物定期行门静脉化疗。对照组在肝癌及门静脉癌栓切除术后未行特殊治疗。结果　对照组与治疗组术后半年、1年复发率分别为 1 4例 (4 8.3% )、2 2例 (75 .9% )和 9例 (2 7.3% )、1 6例 (4 8.5 % ) ;两组术后半年、1年死亡率分别为 1 1例 (37.9% )、1 9例 (6 5 .5 % )与 6例 (1 8.2 % )、1 2例 (36 .4 % )。两组比较均有显著性差异 (P <0 .0 5 )。结论　肝细胞肝癌伴门静脉癌栓行手术切除有较好的疗效。而术后根据药物敏感性试验通过门静脉化疗可明显降低术后复发率 ,延长生存期     

泌尿系感染病原菌的变迁及耐药性分析

目的了解近年来泌尿系感染病原菌的变迁及耐药现状. 方法应用回顾性调查分析方法,对我院1997至2000年间泌尿系感染检测的1 026株病原菌的分布及耐药性进行统计分析. 结果在泌尿系感染的病原菌中,G+球菌上升,G-杆菌下降,真菌上升,其中粪肠球菌上升和变形菌属下降差异有显著性(P<0.05),药敏实验结果对以往常用的抗菌药物青霉素类、复方新诺明、红霉素、诺氟沙星及一代头孢显示较高的耐药性,2000年耐药率>81.6%,对三代头孢、环丙沙星、庆大霉素呈中度耐药,耐药率在42.9%～78.3%,对阿米卡星及头孢哌酮/舒巴坦呈轻度耐药,耐药率<36.7%. 结论随着抗生素的更新换代、人口老龄化及医院感染等因素的变化,泌尿系感染病原菌的分布及耐药性均发生了变迁.     

Cough and converting enzyme inhibitors

Persisting cough developed in three children treated with converting enzyme inhibitors. The symptoms disappeared within 3–7 days after withdrawing medication. These observations in children complement previous reports in adults and indicate that cough may be induced by treatment with these agents.     

Olfactory Absorption of Insulin to the Brain

A vast number of potent neuropharmaceuticals, many of which are peptides, are excluded from entry into the brain because of the highly selective blood-brain barrier. The fact that a number of drugs have been shown to be transported directly to the central nervous system following application to the olfactory region of the nose is therefore of major interest. In the present study, the feasibility of delivering peptides to the brain via the olfactory route was assessed using insulin as a model peptide. Systemic hyperinsulinemia induced by subcutaneous injection did not significantly reduce the amount of ¹²⁵I-insulin transported from the nose to the brain in vivo, which suggests that the impact of systemic absorption on drug transport is minimal. A linear relationship was seen between insulin accumulation in the brain and the dose applied, without any relevant saturation. Contrary to what was expected, both systemic and olfactory absorption of insulin was enhanced when the pH of the medium was near the isoelectric point. The amount absorbed to the brain was found to be linearly related to the net charge of the molecule (r = -0.61; n = 20). It was concluded that insulin gains access to the central nervous system from the olfactory region of the nose by a nonspecific pathway. The olfactory route may therefore become an important means to deliver peptides to the brain.     

Preparation and evaluation of temperature sensitive liposomes containing adriamycin and cytarabine

Temperature sensitive liposomes (TSL) containing adriamycin (ADM) and cytarabine (Ara-C) were prepared. ADM and Ara-C were selected as model compounds of amphiphilic and hydrophilic drug, respectively. Encapsulation efficiency of ADM entrapped into TSL was about twice greater than that of Ara-C. It might be due to different polarity of the drugs. Lipid compositions of TSL had no effect on the encapsulation efficiency of drugs. Thermal behavior of TSL using a differential scanning calorimetry (DSC) was also investigated. Phase transition temperature (T_c) of TSL was dependent on the lipid compositions of TSL.ADM broadened thermogram of TSL but Ara-C did not. However, T_c of TSL was not changed by any drug. Release rate of drugs was highly dependent on temperature. The release profile of ADM was similar to that of Ara-C. The maximum release rate of drugs from TSL was occurred at the near T_c and observed at 39–41°C for DPPC (Dipalmitoylphosphatidylcholine) only, 52–54°C for DSPC (Distearoylphosphatidylcholine) only, 41–43°C for DPPC and DSPC (3∶1), and 43–45°C for DPPC and DSPC (1∶1), respectively. Effect of human serum albumin (HSA) on the release rate of ADM was investigated. HSA had no significant effect on the release of ADM below T_c. However, ADM release from TSL was increased at the near and above T_c. The HSA-induced leakage of drug may result from the interaction of liposomal constituents with HSA structure at the near T_c. From the fact that the release profiles of ADM from freshly prepared TSL and stored TSL for 1 week at 4°C was not changed, the TSL was considered to be stable for at least 1 week at 4°C. Based on these findings, TSL may be useful to deliver drugs to preheated target sites due to its thermal behaviors.     

P-glycoprotein (P-gp) function in T cells: implications for organ transplantation

P-glycoprotein (P-gp), a member of the adenosine triphosphate (ATP)-binding cassette (ABC) family of transporter molecules, is responsible for maintaining low intracellular concentrations of a variety of extracellular compounds and xenobiotics, and for transport of various intracellular molecules. Many drugs are P-gp substrates and intracellular concentrations of these agents may be critical for drug action. Experience in oncology indicates that repeated exposure to P-gp substrate cytotoxic drugs leads to the selection of drug-resistant tumor cells that overexpress P-gp. Since immunosuppressive agents such as cyclosporine, tacrolimus, sirolimus and corticosteroids are substrates for P-gp and since T-cells also express P-gp, it is conceivable that an analogous mechanism exits for therapy-resistant graft rejection. As will be discussed in this article, P-gp may interfere with the response to immunosuppressive therapy through several distinct mechanisms, and as such may represent an attractive therapeutic target.     

Effects of Carbamazepine on Murine Humoral and Cellular Immune Responses

Summary: Oral administration of carbamazepine (CBZ)(15, 10, or 5 mg/kg) to mice significantly decreased both humoral and cellular immune responses evaluated by enumeration of direct and indirect plaque-forming spleen cells (PFC) and delayed–type hypersensitivity reaction (DTH) against sheep red blood cells (SRBC) as compared with those observed in normal control animals. Moreover, spleen T cells obtained from CBZ–treated donor mice were capable of decreasing both PFC and DTH responses of normal spleen cells transferred into lethally irradiated recipient animals. The immunodepressor effect of CBZ was observed even though administration of CBZ induced augmentation of spleen cellularity.     

Pharmacological effects of epibatidine optical enantiomers

The pharmacology of synthetic - and -epibatidine, an alkaloid originally characterized from frog skin, were studied in different behavioral tests in mice and rats. The two enantiomers have potent antinociceptive activity in mice using the tail-flick test, with an ED₅₀ of 6.1 and 6.6 μg/kg for - and -epibatidine respectively. Epibatidine enantiomers were 200 × more potent than -nicotine as an antinociceptive agent in mice after s.c. administration. Their analgesic effect was blocked by mecamylamine but not naloxone, an opiate antagonist. Both - and -epibatidine have high affinity (K_i 54.7 and 55.0 pM, respectively) for [³H]nicotine binding site in rat brain. In addition, they reduced mice locomotor activity and body temperature in a dose-dependent manner. In rats trained with nicotine (0.4 mg/kg), epibatidine enantiomers engendered nicotine-like responding in a dose-related manner with an ED₅₀ of 1.00 and 0.93 μg/kg for and , respectively. The discriminative effect of - and -epibatidine in rats was blocked by mecamylamine but not by hexamethonium. As in binding results, there was no significant enantioselectivity for these effects in our study.