细胞穿透肽YARA介导增强型绿色荧光蛋白转导入人结直肠癌细胞的实验研究

目的 构建原核表达载体pET15b-YARA EGFP,表达并纯化出融合蛋白YARA-EGFP,观察其穿透人结直肠癌细胞的情况.方法 用分子克隆技术构建出表达型载体pET15b-YARA-EGFP,在E.coli BL21(DE3)中表达融合蛋白YARA-EGFP,将鉴定和纯化后的融合蛋白加入体外培养的人结直肠癌细胞.结果 得到纯化的融合蛋白YARA-EGFP,能高效地转导入体外培养的人结直肠癌细胞,并表现出剂量和时间依赖性,MTT法检测在其高浓度时仍对细胞无毒性.结论 YARA-EGFP融合蛋白能高效地转导入体外培养的人结直肠癌细胞.     

P40家族成员及其在自身免疫性疾病中的作用

作为P40家族中研究最为广泛的细胞因子,白细胞介素-12(Interleukin-12)其最显著的特点是有助于Th1细胞分化,参与由Th1细胞所介导的免疫性疾病。而白细胞介素-23(Interleukin-23)与Th17细胞增殖有关,最新发现Th17介导的免疫反应在实验性变态反应性脑脊髓炎(EAE)和多发性硬化症(MS)疾病方面发挥重要作用,并且其分化途径的提出对传统的Th1/Th2细胞免疫也带来了新的挑战[1]。该家族的另外两个成员P40单体和P40同源二聚体也参与免疫调控,实验证明P40分子不仅在细胞内感染及炎症过程中起着重要的调节作用,而且与银屑病、多发性硬化症、Crohn’s病等多种自身免疫性临床疾病的发病密切相关。     

细胞色素P450酶参与动物体内代谢的研究与展望

细胞色素P450酶(Cytochrome P450 enzymes,CYP450)通过其活性部位的Fe3+使底物得到O2 中的一个氧原子并伴随着得失电子来进一步实现化合物的氧化过程.其家族成员CYP3A4 在治疗抗COVID-19 的化学药物中能介导利托那韦(Ritonvir)与洛匹那韦(Lopinavir)的代谢来达...     

海洛因对大鼠谷氨酸脱氢酶基因表达的影响

目的:研究海洛因对大鼠谷氨酸脱氢酶(GDH)基因表达的影响。方法:40只成年♂Wistar大鼠随机分为4组:对照组腹腔注射(ip)生理盐水9d;给药3d组ip海洛因3d;给药9d组ip海洛因9d;停药组ip海洛因9d后停药8d。采用生化自动分析系统检测血浆及组织中GDH活性,逆转录聚合酶链反应法(RT-PCR)检测组织中GDHmRNA的含量。结果:血浆中GDH活性在海洛因给药期间逐渐增高,停药8d后仍无明显降低;大脑组织GDH活性在海洛因给药3d、海洛因给药9d及停药8d后均显著低于对照组(P<0·01);肝脏GDH活性在海洛因给药过程中降低(P<0·01),停药8d后恢复到对照组水平;小肠GDH活性在海洛因给药9d后显著高于对照组(P<0·05),停药8d后小肠GDH活性继续升高并明显高于对照组(P<0·01)和海洛因给药9d组(P<0·05)。大脑、肝脏和小肠GDHmRNA含量分别与其GDH活性变化趋势一致。结论:海洛因对大鼠不同组织GDH基因表达影响不同。     

抗人膀胱癌单克隆抗体重链可变区基因的克隆及原核表达载体的构建

目的 克隆抗人膀胱癌单克隆抗体重链可变区基因(VH),并构建其原核表达载体.方法 从能分泌抗人膀胱癌单克隆抗体的杂交瘤细胞BDI-1中提取总RNA,通过RT-PCR扩增出VH cDNA,用HindⅢ和XhoⅠ酶切纯化的RT-PCR产物和原核表达载体pET28a( ),在T4 DNA连接酶作用下室温连接.重组质粒经酶切鉴定,阳性克隆测序并进行序列分析.结果 扩增出VH cDNA片段,大小约为370bp,重组质粒的酶切鉴定结果与预期一致.VH基因序列长度为366bp,编码122个氨基酸.VH基因属于鼠免疫球蛋白重链Ⅱ亚类.结论 成功克隆出抗人膀胱癌单克隆抗体重链可变区基因,并成功构建其原核表达载体.     

广东部分地区健康人群GSTP1基因多态性研究

目的 了解谷胱甘肽-S-转移酶P1(GSTP1)基因多态性在广东省部分地区健康人群中的分布规律。方法 应用聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)的方法检测广东省粤语言地区224名健康人GSTP1基因型。应用SPSS软件进行统计分析。结果 在所调查人群中野生纯合子GSTP1 ^*A^*/A基因型的频率为66．5％(149／224)；杂合子GSTP1 ^*A/^*G在人群占26．8％，突变纯合子GSTP1 ^*G/^*G占6．7％。经检验这种分布在不同性别、职业、地区以及生活方式人群中的分布均衡。结论 二分类Logistic回归分析结果显示，高血压、冠心病、脑卒中、肺癌及鼻咽癌等家族史在人群中的发生与人群GSTP1不同基因型的分布无显著相关关系。     

P53、Grb7在胃肠道间质瘤中的表达及临床意义

目的探讨P53、Grb7在胃肠道间质瘤（GIST）中的表达及其与GIST生物学行为的关系,为预测该肿瘤的侵袭潜能提供理论依据和可能的预测指标。方法收集58例手术切除的GIST标本,应用免疫组织化学法检测肿瘤组织中P53和Grb7蛋白的表达,并结合病理形态学及生物学行为评价进行统计学分析。结果肿瘤组织中的P53、Grb7阳性率分别为85.2%、83.3%,并随着GIST恶性分级的增高,其表达均出现递增趋势,差异有显著性意义（P〈0.05）;与生长方式、肿瘤大小、肿瘤中心有无坏死、肿瘤细胞特殊排列结构亦有明显关系（P〈0.05）。结论 P53、Grb7蛋白表达与GIST的发生、发展有关,检测P53、Grb7表达结合特殊病理学形态可以作为评价GIST生物学行为及预后的客观指标。     

Gene expression changes induced by ochratoxin A in renal and hepatic tissues of male F344 rat after oral repeated administration

Ochratoxin A (OTA), a naturally occurring mycotoxin, is nephrotoxic in all animal species tested and is considered a potent renal carcinogen, particularly in male rats. Its mechanism of toxicity is still unknown, although oxidative stress appears to be a plausible mechanism. Therefore, the objective of this study was to identify the biological pathways that are modulated in vivo by OTA in male F344 rats in order to gain further insight into its mechanism of renal toxicity. Rats were gavaged daily with OTA (500 microg/kg bw) and gene expression profiles in target and non-target organs were analyzed after 7 and 21 days administration. As was expected, a time-dependent increase of OTA concentrations was found in plasma, kidney and liver, with the concentrations found in both tissues being quite similar. However, histopathological examinations only revealed changes in kidney; signs of nephrotoxicity involving single cell necrosis and karyomegalic nuclei were observed in the treated rats. The number of differentially expressed genes in kidney was much higher than in liver (541 versus 11 at both time points). Several similarities were observed with other in vivo gene expression data. However, great differences were found with previous in vitro gene expression data, with the exception of DNA damage response which was not observed at mRNA level in any of our study conditions. Down-regulation was the predominant effect. Oxidative stress response pathway and genes involved in metabolism and transport were inhibited at both time points. RGN (regucalcin) - a gene implicated in calcium homeostasis - was strongly inhibited at both time points and genes implicated in cell survival and proliferation were up-regulated at day 21. Moreover, translation factors and annexin genes were up-regulated at both time points. Apart from oxidative stress, alterations of the calcium homeostasis and cytoskeleton structure may be present at the first events of OTA toxicity.     

天蚕素A截短肽在大肠埃希菌中的高效表达及活性分析

将构建好的含抗菌肽天蚕素A(cecropin A,CA)截短肽CA19(36、210)1～5倍串连体的pET-31b(+)载体进行诱导表达,其表达量比单体表达明显提高.将融合蛋白用亲和层析法将其纯化,其纯度达到90%以上.纯化融合蛋白免疫BALB/c小鼠,制备了其特异的多克隆抗体.纯化串连融合蛋白用溴化氰切割成单体检测其活性,发现均具有抑菌活性.本研究为抗菌肽的基因工程制备提供了新途径.     

Prediction of Phase I single-dose pharmacokinetics using recombinant cytochromes P450 and physiologically based modelling

1. Ten compounds from the Merck Research Laboratories pipeline were selected to evaluate the utility of using intrinsic clearance derived from recombinantly expressed cytochromes P450 (CYP) and physiologically based pharmacokinetic modelling to predict Phase I pharmacokinetics using simCYP. The compounds selected were anticipated to be eliminated predominantly by P450 metabolism.

2. There was a reasonable agreement between the predicted and actual clinical exposure with 80% of the predicted exposures being within three-fold of the observed values. Furthermore, prediction of C(t) (plasma concentration at a specified time point) and T_max were acceptable with greater than or equal to 70% of the predicted data being within three-fold of the observed values. However, prediction of C_max was unreliable and may have been due to error in predicting the time-dependent change in volume of distribution and/or error in estimating absorption rate.

3. Although it is acknowledged that research is needed to improve predictive performance, the data presented are supportive of using recombinant P450 intrinsic clearance and physiologically based pharmacokinetic modelling to predict Phase I pharmacokinetics for compounds eliminated by P450 metabolism.