CD95在胰腺癌细胞化疗敏感性中的作用研究

目的 探讨CD95系统在胰腺癌细胞对化疗敏感性中的作用。方法 通过脂质体介导将CD95基因转入胰腺癌细胞株SW1990，G418筛选转导CD95基因的细胞克隆，Northern-blot和Western-blot检测转导细胞中CD95的表达；MTT法观察转导细胞对氟尿嘧啶（5-FU）、阿霉素（ADM）、双氟脱氧胞苷（GCB）及与抗CD95单克隆抗体联合治疗的反应；流式细胞仪（FCM）检测化疗药诱导转导细胞凋亡的作用。结果 CD95基因转导的SW1990细胞可稳定地过表达CD95，其mRNA与蛋白的表达均较未转导及空白对照组显著增高，抗CD95单抗可阻滞转导细胞的生长。临床相关药物浓度的化疗药对转导细胞的生长抑制作用明显高于未转导细胞，加入抗CD95单抗可显著增强化疗药的作用。ADM诱导胰腺癌细胞凋亡作用较明显，且转导细胞显著高于未转导细胞，结论 转导CD95基因可提高SW1990细胞对化疗药的敏感性，部分逆转其耐药性，化疗药与抗CD95单抗联合应用对胰腺癌细胞具有协同作用。     

Fas/FasL介导的凋亡在桥本病发病机制中的作用

用免疫组织化学法和Westem印迹法在24例桥本病(HT)甲状腺组织中观察到甲状腺细胞Fas表达增高，Fas／FasL介导的细胞凋亡参与HT的发病。     

Pharmacological basis for cladribine resistance in a human acute T lymphoblastic leukaemia cell line selected for resistance to etoposide

Cross-resistance between different classes of anti-neoplastic agents can jeopardize successful combination cancer chemotherapy. In this study, we observed an unexpected cross-resistance between the podophyllotoxine derivative etoposide (VP) and the nucleoside analogue cladribine (CdA) in CCRF-CEM cells developed for resistance to VP. The resistant cells also displayed 14- and twofold resistance to cytarabine (ara-C) and gemcitabine respectively. Closer analysis of these cells showed that they contained lower amounts of topoisomerase (topo) IIalpha (P < 0.001) and beta protein (P < 0.026), formed substantially lower amounts of the topo II-DNA complex, and had a markedly decreased level of Fas (CD95/APO-1)-ligand mRNA expression. Interestingly, Fas expression in the resistant cells did not differ from that in the parental cell line. No differences were observed in the accumulation/efflux of daunorubicin or in the gene expressions of P-glycoprotein, multidrug resistance-associated protein and the lung resistance-related protein. The activity of deoxycytidine kinase (dCK), responsible for activation of CdA and ara-C, was the same for resistant and wild-type cells. However, there was an increase in the activity of the cytosolic 5'-nucleotidases (5'-NT), responsible for deactivation of nucleotides, amounting to 206% (P < 0.001) for the high Km and 134% (P < 0.331) for the low Km 5'-NT in resistant cells. The high Km 5'-NT is probably responsible for the decreased amount of the active metabolite CdA 5'-triphosphate [40% decreased (P < 0.045)], as well as for other purine ribonucleosides and deoxyribonucleosides triphosphates in the resistant cells. In contrast, a significantly higher deoxycytidine triphosphate (dCTP) level (167%, P < 0.001) was observed in the resistant cells. Thus, this study suggests that the major cause of resistance to the nucleoside analogues CdA and ara-C in cells selected for resistance to VP is a result of metabolic alterations producing increased activity of 5'-NT and higher dCTP levels. Furthermore, these results indicate that there is a common factor in the regulation of nucleotide-degrading enzymes and DNA topoisomerases, which may be altered in cross-resistant cells.     

N-甲基-D-天冬氨酸受体和突触后致密物质95在血管性痴呆大鼠中作用机制的研究

目的观察血管性痴呆(VaD)大鼠N-甲基-D-天冬氨酸-2B亚基受体(NR2B)和突触后致密物质95(PSD-95)在VaD发生、发展中的作用。方法采用永久性结扎双侧颈总动脉方法将96只Wistar大鼠随机分为假手术组(32只)、VaD模型组(模型组,32只)和美金刚治疗组(治疗组,32只)。用免疫组织化学法检测术后4、8、12、16周大鼠海马NR2B和PSD-95的表达,并同时采用Morris水迷宫测试大鼠的学习记忆水平。结果随着缺血时间的延长,与假手术组比较,模型组大鼠术后4、8、12、16周学习记忆能力下降,差异显著(P<0.01);术后4周时NR2B和PSD-95的表达明显高于假手术组(P<0.01),此后逐渐减少,显著低于假手术组(P<0.01),术后16周时表达最少。治疗组大鼠术后4周时学习记忆水平及NR2B、PSD-95的表达与假手术组比较无显著差异,术后8、12、16周时,上述指标较模型组显著好转但仍差于假手术组(P<0.05,P<0.01)。结论大鼠海马NR2B和PSD-95作为复合体参与VaD的形成和发展,适量的美金刚通过调节NR2B的表达进而改善VaD大鼠的认知功能。     

Arsenic methylation capacity is associated with breast cancer in northern Mexico

Exposure to environmental contaminants, dietary factors and lifestyles may explain worldwide different breast cancer (BC) incidence. Inorganic arsenic (iAs) in the drinking water is a concern in many regions, such as northern Mexico. Studies in several countries have associated the proportion of urinary monomethylarsenic (%MMA) with increased risks for many As-related diseases, including cancer. To investigate the potential relationships between the risk of BC and the capacity to methylate iAs, a hospital-based case–control study (1016 cases/1028 controls) was performed in northern Mexico. Women were directly interviewed about their reproductive histories. The profile of As metabolites in urine was determined by HPLC-ICP-MS and methylation capacity was assessed by metabolite percentages and indexes. Total urinary As, excluding arsenobetaine (TAs-AsB), ranged from 0.26 to 303.29 μg/L. Most women (86%) had TAs-AsB levels below As biological exposure index (35 μg/L). Women with higher %MMA and/or primary methylation index (PMI) had an increased BC risk (%MMA OR_Q5vs.Q1 = 2.63; 95%CI 1.89,3.66; p for trend < 0.001; PMI OR_Q5vs.Q1 = 1.90; 95%CI 1.39,2.59, p for trend < 0.001). In contrast, women with higher proportion of urinary dimethylarsenic (%DMA) and/or secondary methylation index (SMI) had a reduced BC risk (%DMA OR_Q5vs.Q1 = 0.63; 95%CI 0.45,0.87, p for trend 0.006; SMI OR_Q5vsQ1 = 0.42, 95%CI 0.31,0.59, p for trend < 0.001). Neither %iAs nor total methylation index was associated to BC risk. Inter-individual variations in iAs metabolism may play a role in BC carcinogenesis. Women with higher capacity to methylate iAs to MMA and/or a lower capacity to further methylate MMA to DMA were at higher BC risk.     

Increase in CD95 (Fas/APO-1)-positive CD4+ and CD8+ T cells in peripheral blood derived from patients with autoimmune hepatitis or chronic hepatitis C with autoimmune phenomena

BACKGROUND: The expressions of CD95 (Fas/APO-1) and Bcl-2 are determinants of apoptosis in normal lymphocytes, and abnormalities in their expressions might contribute to the induction of autoimmunity. In this study, we examined the expressions of CD95 and Bcl-2 on freshly isolated T and B cells from patients with autoimmune hepatitis (AIH) or chronic hepatitis C associated with autoimmune phenomena (CH-C(AI)). METHODS: The CD95 and Bcl-2 expressions within CD4+ T, CD8+ T, and CD19+ B cell subsets were analysed by two-colour flow cytometry. RESULTS: The surface expression of CD95 was significantly high in both the CD4+ T and CD8+ T cell subsets derived from the patients with AIH and those with CH-C(AI), compared with expression in patients with CH-C and normal subjects. The increase in CD95 expression was associated with the phenotypic conversion of naive CD45RO- to primed CD45RO+ CD4+ T cells. Bcl-2 was detected in the vast majority of peripheral T and B cells. There was no significant difference in the percentage of Bcl-2-positive cells in the CD4+ T cell, CD8+ T cell and CD19+ B cell subsets among the patient groups and normal subjects. CONCLUSIONS: These results indicate that an increase in CD4+ T cells expressing CD45RO and CD95 marks an important subset of AIH and CH-C(AI) patients. These expanded CD95+ CD45RO+ primed T cells most likely reflect a continuous antigen-specific or non-specific activation of T lymphocytes, and/or the persistent presence of activated lymphocytes as a consequence of abnormalities in the peripheral deletion of activated lymphocytes. These persistently activated lymphocytes might play a role in the induction of autoimmunity in AIH and CH-C(AI).     

联合应用顺阿曲库铵与维库溴铵后ED50和ED95的改变

目的：观察顺式阿曲库铵联合维库溴铵用药后ED50和ED95的变化。方法将75例择期手术患者（ASAⅠ~Ⅱ级）随机分为3组：顺式阿曲库铵组、维库溴铵组和顺式阿曲库铵＋维库溴铵组,每组各25例。麻醉诱导后,以单次给药法观察起效时间和T1达到最大抑制的时间,描绘3组患者的量-效曲线,求得各自的ED50和ED95值,并运用等效图法和代数法对两药相互作用进行分析。结果单用顺式阿曲库铵组、维库溴铵组ED50值分别为32.35、28.78μg/kg,ED95值分别为52.67、51.20μg/kg。联合用药时ED50值为16.81、12.17μg/kg,ED95值为23.49、22.16μg/kg,与单独用药相比,差异均有统计学意义。联合用药时ED50和ED95的合用代数值分别为0.942、0.879。结论联合使用顺式阿曲库铵和维库溴铵具有协同作用,且量-效曲线产生左移。     

儿童系统性红斑狼疮患者外周血淋巴细胞表面CD95的表达及临床意义

目的:探讨儿童系统性红斑狼疮(systemic lupus erythematosus,SLE)外周血淋巴细胞表达CD95的特征及与疾病活动性和其他免疫学指标间的关系.方法:使用流式细胞术检测60例SLE患儿和20例对照外周血T淋巴细胞亚群和B淋巴细胞表面CD95的表达,并分析其与SLE疾病活动性以及实验室检查之间的关系.结果:初发SLE患儿外周血中CD4+T细胞表面CD95的表达显著高于对照组,差异有统计学意义(P<0.05);初发SLE患儿外周血中CD19+B细胞表面CD95的表达显著高于健康儿童(P<0.05);CD19+CD95+B细胞的比例和SLE疾病活动性呈正相关(r=0.4,P<0.05);CD4+CD95+T细胞的比例和SLE疾病活动性呈正相关(r=0.3,P<0.05),CD4+CD95+T细胞的比例和外周血抗双链DNA抗体(anti-dsDNA Abs)的水平呈正相关(r=0.2,P<0.05);治疗后SLE患儿外周血中CD19+CD95+B细胞和CD4+CD95+T细胞的比例均有显著下降,差异有统计学意义(P<0.05).结论:儿童SLE患者外周血中淋巴细胞表达CD95的水平显著升高,且与SLE的疾病活动性及血清中抗双链DNA抗体相关,可以作为SLE的评价指标.     

Graves病患者血清中凋亡抑制因子sFas、Bcl-2的初步研究

用ELISA法检测 3 0例Graves病患者治疗前后及 3 2例正常对照组血清中凋亡抑制因子sFas、Bcl 2 ,发现Graves病患者治疗前sFas〔(0 .76± 0 .2 4)ng/L〕、Bcl 2〔1.0 2± 0 .2 3 )ng/L〕含量升高 ;治疗后 (0 .5 2±0 .0 8)ng/L ;(0 .87± 0 .15 )ng/L〕下降 ,与正常对照组〔(0 .5 3± 0 .0 9)ng/L ;(0 .81± 0 .15 )ng/L〕差异无显著性 ,提示sFas、Bcl 2可能参与Graves病的发病。