人ZEB1基因真核表达载体的构建及其对肝癌细胞株HepG2增殖凋亡的影响

目的：探讨ZEB1基因与肝癌的关系,进一步揭示ZEBl基因在肝癌发生发展过程中的作用。方法：利用基因重组技术构建pCI-neo-ZEB1真核表达载体：脂质体介导转染技术转染肝癌细胞系HepG2。采用WesternBlot技术检测重组质粒的转染效率,CCK8比色法测定重组质粒转染对HepG2细胞体外增殖能力的影响,流式细胞术检测重组质粒转染后HepG2细胞凋亡率。结果：重组质粒经Nhel和Xbal双酶切、测序与ZEBl基因序列一致;利用脂质体介导将pCI-neo-ZEB1重组质粒转染HepG2细胞株,经WesternBlot技术检测ZEB1基因在蛋白水平稳定高表达;与对照组比较,人HepG2细胞株转染pCI-neo-ZEB1真核表达载体后细胞增殖能力增强,细胞凋亡率明显降低。结论：成功构建重组质粒Pci-neo-ZEB1并转入肝癌细胞株HepG2后,细胞增殖能力增强,凋亡减少。     

HBx基因真核表达载体的构建及表达

目的 构建重组HBx蛋白的真核表达载体pIRES2-AcGFP-HBx.方法 设计合成HBx基因的特异性PCR引物.PCR扩增获得HBx基因序列;将HBx基因序列克隆人T载体(pGEM-T-HBx);再用限制性内切酶BglⅡ和EcoR Ⅰ双酶切下目的片段,将其亚克隆人真核表达载体pIRES2-AcGFP;双酶切(Bgl Ⅱ和EcoR Ⅰ)和序列测定鉴定重组子;脂质体包裹pIRES2-AcGFP-HBx转染入HepG2细胞,G418筛选得到稳定表达HBx的细胞克隆,Western blot检测HBx蛋白在转染细胞中的表达情况.结果 PCR扩增获得全长HBx基因序列;双酶切筛选得到阳性重组子,测序分析证实插入序列正确;转染plRES2-AcGFP-HBx的HepG2细胞,荧光显微镜可观察到GFP的表达,Western blot 证实表达HBx蛋白.结论 成功构建重组HBx基因真核表达载体,获得稳定表达HBx蛋白的HepG2细胞株,为深入研究HBx蛋白的生物学功能提供实验条件.     

人miR-155真核过表达载体的构建及其对HepG2.2.15细胞中HBeAg的抑制效应

目的:构建人microRNA-155(miR-155)真核过表达载体,并探讨其对HepG2.2.15细胞中乙型肝炎e抗原(hepatitis B e antigen,HBeAg)的抑制作用,为研究其基因调控机制对乙型肝炎病毒(hepatitis B virus,HBV)复制及免疫状态影响提供实验基础.方法:以人肝癌细胞系HepG2.2.15细胞基因组为模板,通过PCR扩增人miR-155前体序列,酶切后连接到pmR-mCherry质粒,构建pmiR-155真核过表达载体,然后进行酶切和测序鉴定.利用脂质体将pmiR-155转染HepG2.2.15细胞,同时设空质粒(pmR-mCherry质粒)转染组和空白对照组.转染24 h后荧光显微镜下观察细胞内Cherry表达,RT-PCR检测各组细胞内miR-155表达量以及ELISA法检测HBeAg分泌量的改变.结果:经测序证实,成功构建人pmiR-155真核过表达载体.转染细胞后进行应荧光观察,载体中Cherry有较好的表达活性.RT-PCR表明,与对照组细胞相比,pmiR-155组细胞内所表达的miR-155明显提高.ELISA结果示pmiR-155组细胞所分泌的HBeAg量显著低于空载组和空白组.结论:成功构建了人miR-155真核过表达载体;转染HepG2.2.15细胞后表达稳定;蛋白水平检测表明其可以抑制HepG2.2.15细胞中HBeAg的表达.     

APP基因真核表达载体的构建及其在SH-SY5Y细胞中的稳定表达

目的 构建淀粉样前体蛋白(APP)基因真核表达载体,转染SH-SY5Y细胞,建立稳定转染细胞系.方法 从质粒pcDNAs-APP中经PCR扩增出APP基因,利用DNA重组技术将其插入到真核表达载体pcDNA3.1(+)中,经酶切和测序鉴定后,脂质体转染法转染SH-SY5Y细胞,通过G418选择培养,建立稳定转染细胞系,通过印迹法(Western blot)检测APP的表达. 结果 pcDNA3.1(+)-APP重组体经PCR扩增后片段大小约为2 300 bp,与预期相同.测序结果与目的序列相同,重组体载体构建成功.Western印迹检测到SH-SY5Y细胞中APP的表达. 结论 成功构建pcDNA3.1(+)-APP真核表达载体并稳定转染SH-SY5Y细胞,成功表达了目的基因,为进一步研究阿尔茨海默病分子学机制奠定了基础.     

pcDNA3.1-CD81载体在人肝癌细胞中的表达及意义

目的研究人白细胞分化抗原CD81真核表达载体pcDNA3．1-CD81在人肝癌细胞系HepG2中的表达及意义。方法由人Molt-4细胞提取细胞总RNA，根据已公布的序列设计引物，运用RT-PCR及PCR方法扩增出人CD81基因，应用TA克隆插入PMD-18T载体；定向克隆入真核表达载体pcDNA3．1( )；通过脂质体介导转染人肝癌细胞系HepG2，用免疫组织化学方法(ABC法)及流式细胞技术检测目的蛋白的表达。结果由RT-PCR及PCR方法扩增出入CD81编码基因与Genebank公布的序列完全一致。重组真核表达载体pcDNA3．1-CD81经酶切和PCR鉴定分析正确。免疫组织化学方法(ABC法)及流式细胞技术证明转染的HepG2细胞表面能有效地表达CD81蛋白。结论所构建的pcDNA3．1-CD81真核表达载体在HepG2细胞有良好的表达，该转染细胞可作为研究CD81在HCV感染中的作用提供细胞模型，为研究丙型肝炎病毒(HCV)与CD81相互作用奠定基础。     

恶性疟原虫复合抗原重组真核表达质粒的构建与表达

目的　构建编码恶性疟原虫不同发育期抗原表位的复合抗原基因HGFSP的重组真核表达质粒。　方法　将HGFSP亚克隆于真核表达载体pcDNA3构建重组真核表达质粒 pc HGFSP ;琼脂糖凝胶电泳和限制性内切酶分析鉴定 ;脂质体介导转染HepG2细胞。取经G418筛选的阳性细胞克隆进行免疫学鉴定。 　结果　酶切及电泳鉴定证实pc HGFSP含有HGFSP。间接免疫荧光试验 (IFAT)、SDS PAGE及Westernblotting结果显示 ,pc HGFSP转染细胞含有可与HGFSP原核表达蛋白免疫血清产生特异性免疫反应的蛋白 (包含恶性疟原虫MSA1、MSA2、RESA和CSP中的抗原表位 ) ,其分子量与按HGFSP长度推算的蛋白分子量接近。　结论　用HGFSP成功构建恶性疟原虫复合抗原真核表达质粒 pc HGFSP ,其表达产物具免疫反应性。     

人HNF4α基因真核表达载体的构建与鉴定*

目的体外构建人肝细胞核因子4α（HNF4α）基因真核表达载体,并初步鉴定其在HepG2细胞的表达。方法从肝癌手术患者获得肝组织,分离得到肝组织总RNA,将其逆转录合成cDNA,经特异性引物扩增HNF4α基因片段,将其定向连接到pcDNA3.1(+）真核表达载体,经抗生素筛选后,酶切及测序鉴定其序列正确。提取质粒,转染HepG2细胞,48 h后裂解细胞,应用抗HNF4α行Western blot检测目的蛋白。结果从临床肝癌患者肝组织中成功分离得到总RNA,扩增出HNF4α基因,经筛选、酶切鉴定和测序,确认pcDNA3.1-4α真核表达载体构建成功。在转染HepG2细胞48 h后,检测显示53 kDa位置有明显融合蛋白条带。结论我们成功构建了HNF4α基因真核表达载体,体外转染HepG2细胞成功表达HNF4α蛋白,为后续研究奠定了基础。     

pCMV-tag2B—HBX质粒的构建和表达

目的构建乙型肝炎病毒X基因（HBX）的真核表达质粒，诱导并鉴定其表达。方法将克隆获得的HBX全长cDNA片段插入带有报告基因的真核表达质粒pCMV-tag2B，构建HBX的重组表达载体pCMV-tag2B—HBX，经DNA测序证明HBX的cDNA片段的插入方向和其全长cDNA的碱基顺序，将重组质粒转染HepG2细胞系，诱导其表达，用Western Blot进行鉴定。结果构建的重组表达载体pCMV-tag2B-HBX经双酶切表明有相应大小的DNA片断，序列分析证实为正确的有完整读码框的X基因，用脂质体转染法可将pC-MV-tag2B-HBX导入HepG2细胞并成功表达，目的蛋白经Western Blot鉴定具有生物学活性。结论成功构建了HBX真核表达质粒pC-MV-tag2B-HBX，重组质粒能表达具有生物学活性的HBX蛋白，为研究HBX的功能打下了基础。     

HEV ORF3真核表达载体的构建、鉴定和真核表达

目的构建表达戊型肝炎病毒(HEV)ORF3-pXF2RH融合蛋白的真核表达载体;获得重组质粒稳定转染的L02细胞系。方法利用PCR技术从HEV基因组中扩增出ORF3基因片断,HindⅢ/EcolⅠ双酶切后连接到经同样酶切的pXF2RH真核表达载体,转化DH5α菌株感受态细胞,获得阳性重组质粒ORF3-pXF2RH。将阳性克隆用脂质体法转染L02细胞系,G418筛选抗性克隆,SDS-PAGE、Western blot分析鉴定ORF3-pXF2RH融合蛋白的表达。结果真核表达质粒转染L02细胞,SDS-PAGE显示在28.5kD左右蛋白表达量明显高于对照组,Western blot在28.5kD左右有一条强的棕色条带。结论成功构建ORF3-pXF2RH真核表达质粒,在L02细胞表达融合蛋白,为进一步研究该蛋白生物学功能奠定了基础。     

携带融合基因穿梭质粒的构建及在人肝癌细胞中的表达

构建携带胸苷激酶(tk)与增强型绿色荧光蛋白(EGFP)融合基因穿梭质粒,并观察其在肝癌细胞系HepG2细胞中的表达。应用基因重组技术,构建EGFP与tk的融合表达穿梭质粒载体,经限制酶切鉴定和测序分析,脂质体转染将其导入HepG2中,48h后用荧光显微镜观察荧光的表达,RT-PCR法检测融合蛋白tk和EGFP的mRNA表达,四甲基偶氮唑蓝(MTT)实验检测转染融合蛋白载体后不同浓度的更昔洛韦(GCV)对HepG2细胞的细胞毒作用。酶切鉴定和测序分析证实重组质粒中插入融合目的基因片断及载体DNA大小、方向和插入位点正确,在转染此穿梭质粒的HepG2细胞中检测到绿色荧光蛋白的表达,RT-PCR检测到融合蛋白tk和EGFP的mRNA表达;GCV对转染了携带tk与EGFP融合基因穿梭质粒载体有明显的细胞毒作用。成功构建携带tk与EGFP融合基因穿梭质粒载体,转染人肝癌细胞株HepG2中tk和EGFP的独立表达没有受到影响,该载体可利用绿色荧光蛋白作为报告基因监测tk的表达并可用于肝癌的自杀基因治疗。     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Presence of immunoreactive growth hormone and prolactin in the ovine pineal gland

Abstract: The use of antisera raised against bovine growth hormone (GH) and ovine prolactin (PRL) enabled the detection of related immunoreactive (ir) sequences of proteins in ovine pineal tissue. The isolation of PRL-like ir-material was accomplished using a 0.25 M ammonium sulphate (pH 5.5) extraction followed by ethanol precipitation, whereas the resulting 2.0 M ammonium sulphate (pH 7.0) precipitate contained a GH-like immunoreactivity. Gel chromatography of the GH-like immunoreactivity (Sephadex G-100) indicated the presence of several GH-like fragments ranging in the M_r range of 7,000 to 55,000. Analyses of the PRL-like ir-material found in pineal tissue on HPLC using a TSK 545-DEAE column led to the resolution into a single peak of immunoreactivity. A single peak of activity was also observed following chromatofocusing and hydrophobic interaction chromatography of the ir-peak from the TSK 545-DEAE column. The PRL-like ir-material inhibited the binding of [¹²⁵I]ovine PRL-S14 to anti-ovine PRL antibodies without showing an affinity for binding to anti-rat PRL or anti-bovine GH antibodies. Scatchard analysis of the binding of pineal PRL-like ir-material and pituitary ovine PRL-S14 to liver membranes from day-20 pregnant rats revealed similar affinity constants (K_a of 4.7 ± 0.2 × 10⁹ M^-1). In addition, the replication of Nb 2 Node rat lymphoma cells was stimulated by pineal PRL-like ir-material, an effect known to be specific for lactogenic hormones. The pineal PRL-like immunoreactivity appeared on sodium dodecyl sulfate polyacrylamide gels as a single major band of M_r 24,000. The functional status of PRL-and GH-like ir-material in the ovine pineal remains to be determined, but evidence is presented that the overall protein synthesis rate of the rat pineal responded to circulating concentrations of PRL.     

Microbiology of human immunodeficiency virus anorectal disease

PURPOSE: Individuals who are seropositive for the human immunodeficiency virus are at high risk for opportunistic infection and anorectal disorders. Little prospective information is available regarding anorectal pathogens in these patients. METHODS: One hundred sixty-three HIV-seropositive patients presented to the colorectal clinic between 1989 and 1992. Forty-seven (29 percent) patients were thought to have an infectious process and were prospectively studied using a standardized multiculture protocol. RESULTS: Mean age was 33 (range, 19–59) years. All were male; high-risk behavior accounted for 87 percent of HIV transmissions. Presenting complaints included anorectal pain (79 percent), pus per anum (28 percent), and blood per anum (26 percent). Examination revealed perianal tenderness (60 percent), condyloma (38 percent), perianal ulcers (38 percent), and anal fissures (34 percent). Sixty-six sets of cultures were performed; 28 patients had one set, 15 had two sets, and 4 had three sets. Thirty-two of these 47 patients (68 percent) had positive cultures including herpes (50 percent), cytomegalovirus (25 percent),Neisseria gonorrhoeae (16 percent), chlamydia (16 percent), acidfast bacilli (2 percent), and others (9 percent). Six of 32 patients with positive cultures had more than one organism cultured. Sixteen (50 percent) patients with positive cultures were treated medically, 8 (25 percent) were treated surgically and 8 (25 percent) were treated with both modalities. Sixty-one procedures were performed on 17 patients for condylomata. Eighteen patients had 20 procedures for abscesses, 50 percent of whom had positive cultures for other than common bowel flora; all improved. Fourteen patients underwent 33 procedures for perianal fistulas.Mycobacterium fortuitum was cultured from one patient who required 13 procedures for abscesses and fistulas. Forty-five (96 percent) patients were followed for an average of 12.5 months ±2.9 SEM (range, 1–94 months). Symptoms were improved or resolved in 22 of 32 (69 percent) patients with positive cultures and in 11 of 13 (84 percent) with negative cultures. CONCLUSIONS: Specific pathogens may often be identified in human immunodeficiency virus-seropositive patients with anorectal disorders if aggressively sought. Although patients without specific pathogens identified may be expected to improve with planned empiric treatment, positive identification allows more directed therapy.