pEGFP-C1-反义生存素重组质粒的构建和转染

目的 构建pEGFP-C1-反义生存素（survivin)重组质粒，并转染入人MKN-45低分化胃腺癌细胞株，观察转染前后生存素基因的表达及对凋亡的影响。从基因水平探讨反义生存素核酸治疗胃癌的分子生物学机制。为今后利用反义基因治疗肿瘤提供实验和理论依据。方法 应用基因重组技术构建 pEGFP-C1-反义生存素重组质粒，通过脂质体转染法转染人MKN-45胃腺癌细胞株，以流式细胞仪方法检测细胞凋亡，以RT-PCR技术检测质粒转染前后生存素基因mRNA的表达。结果 pEGFP-C1-反义生存素重组质粒转染MKN-45低分化胃腺癌细胞株后细胞凋亡明显增加，G2/M期细胞减少，同时生存素基因在mRNA水平被抑制。结论 反义生存素核酸能抑制细胞增殖。减少生存素基因的mRNA表达而促进胃癌细胞凋亡。     

重组DNA甲基化酶1表达质粒对结肠癌细胞相关基因表达的影响

目的 分析DNA甲基化酶1(DNMT1)基因的真核表达质粒对人结肠癌细胞肿瘤相关基因的表达影响。方法 分别构建并转染含有人正义和反义DNMT1的真核表达质粒入结肠癌SW1116细胞，PCR和限制性内切酶证实转染结果，以Western印迹法分析各组细胞DNMT1蛋白的表达情况。定量PCR检测hMLH1、hMSH2及c—myc、p16^INK4A基因的表达。结果 经G418筛选得到稳定转染DNMT1基因的结肠癌细胞系，且分别在该转染有正义和反义质粒的细胞系中，DNMT1蛋白表达上调和下调。同时发现转染正义DNMT1的细胞中hMLH1、hMSH2及c—myc的表达降低，而转染反义DNMT1的细胞中hMSH2的表达明显增强。各组细胞p16^INK4A基因的表达差异不明显。结论 DNMT1基因调控人结肠癌细胞中肿瘤相关基因的表达。     

生存素反义核酸诱导肝癌细胞株SMMC-7721凋亡和增加其对抗肿瘤药物敏感性的研究

背景：生存素是凋亡抑制蛋白家族的重要成员，生存素基因有可能成为肿瘤反义基因治疗的理想靶基因。目的：研究生存素反义核酸诱导肝癌细胞株SMMC-7721凋亡和增加其对常用抗肿瘤药物敏感性的作用，探讨生存素反义核酸用于肿瘤基因治疗的可能性。方法：应用基因重组技术构建pEGFP-C1-生存素反义核酸重组质粒，以脂质体转染法转染SMMC．7721细胞，用逆转录聚合酶链反应(RT-PCR)检测生存素mRNA的表达，用流式细胞仪检测细胞凋亡。将生存素反义核酸分别与7种常用抗肿瘤药物共同作用于SMMC-7721细胞，用四唑蓝(MTT)比色法测定细胞杀伤率。结果：生存素反义核酸可抑制SMMC-7721细胞中生存素mRNA的表达，从而导致细胞凋亡增加，其作用呈剂量依赖性。生存素反义核酸可增加SMMC-7721细胞对7种常用抗肿瘤药物的敏感性，明显增强药物的杀伤作用。结论：生存素反义核酸能靶向抑制野生型生存素基因的表达，提高肝癌细胞对常用抗肿瘤药物的敏感性，有可能成为肿瘤基因治疗的新方法。     

STAT3靶向短发夹RNA干扰重组载体对结肠癌SW480细胞的沉默作用

目的 探讨STAT3基因短发夹RNA(shRNA)表达质粒对结肠癌SW480细胞STAT3基因的干扰作用.方法 根据siRNA设计原则,构建靶向STAT3基因的短发夹RNA干扰质粒(pGPU6/GFP/STAT3),使用脂质体法转染人结肠癌细胞系(SW480),通过RT-PCR和 Western 印迹检测结肠癌SW480细胞STAT3基因mRNA和蛋白表达水平.结果 pGPU6/GFP/STAT3重组质粒经限制性内切酶酶切及测序证明基因插入正确.质粒成功转染SW480细胞后,该细胞的STAT3 mRNA和蛋白表达明显下降(P<0.05).结论 成功构建靶向STAT3基因的shRNA表达载体,转染SW480细胞,能有效抑制细胞的STAT3 mRNA和蛋白表达,为STAT3基因靶向治疗提供前期的实验依据.     

结直肠癌缺失基因功能区诱导结肠癌细胞凋亡

目的检测结直肠癌缺失(DCC)基因功能区转染表达后对结肠癌细胞SW1116凋亡的诱导作用。方法通过脂质体法将含有DCC基因胞内区功能域(3 727～3 792 bp)的重组表达载体pIRES2-EGFP-DCC转染到结肠癌细胞SW1116,MTT比色法检测细胞增殖情况,TUNEL、AO/EB染色法检测细胞凋亡情况。结果转染SW1116细胞36 h后,MTT比色法检测结果表明实验组细胞数目低于对照组,并且具有显著性差异;AO/EB染色及TUNEL法检测结果表明实验组有大量凋亡细胞,对照组未见凋亡细胞。结论 DCC基因的胞内功能域(3 727～3 792 bp)具有诱导结肠癌细胞凋亡的作用。     

siRNA沉默PPARα减弱羟喜树碱诱导的人结肠癌细胞凋亡

背景:多药耐药一直是遏制提高结肠癌化疗有效性的瓶颈问题。目的:探讨沉默PPARα能否减弱羟喜树碱诱导的人结肠癌细胞凋亡,从而阐明PPARα在羟喜树碱耐药中的潜在作用。方法:构建针对PPARα基因的siRNA干扰载体,并转染人结肠癌SW1116细胞,经G418筛选出稳定转染的细胞,以RT-PCR和蛋白质印迹法验证干扰效果。经羟喜树碱干预后,以MTT法检测细胞增殖,Annexin V-FITC/PI检测细胞凋亡。以定量RT-PCR检测不同浓度miR-506前体转染SW1116细胞后对PPARα下游调控靶基因mRNA表达的影响。结果:siRNA干扰载体Ⅲ的沉默效果最佳,PPARα mRNA和蛋白表达分别下调了约94.1%±3.4%和70.8%±8.6%。稳定转染siRNA的SW1116细胞的半数抑制浓度(IC_(50))为(332±19)μg/L,亲本SW1116细胞为(152±12)μg/L。在相同浓度羟喜树碱的作用下,亲本SW1116细胞的凋亡率显著高于稳定转染siRNA的SW1116细胞(150μg/L:7.0%±2.5%对2.8%±1.6%;300μg/L:32.4%±7.1%对18.5%±2.7%)。miR-506前体下调HMGCS-2表达,上调FABP-2、CCND1和TGF-β1表达,其中上调CCND1的作用最为明显。结论:成功构建了针对PPARα的siRNA干扰载体;沉默PPARα能增强SW1116细胞对羟喜树碱的抵抗性,可能与下调HMGCS-2表达并上调FABP-2、CCND1和TGF-β1表达有关。     

人膀胱移行细胞癌中生存素mRNA的表达及与细胞凋亡的关系

目的检测膀胱癌中生存素(Survivin)基因表达,探讨其与细胞凋亡的关系。方法采用原位杂交、免疫组织化学技术和DNA原位末端标记技术,检测46例膀胱癌组织、15例正常膀胱组织生存素mRNA及膀胱癌中caspase3蛋白和细胞凋亡。结果与正常膀胱组织相比,生存素mRNA显著表达于膀胱癌中,并与病理分级有关(P<0.05);膀胱癌中caspase3蛋白与凋亡细胞阳性率分别为76.1%和67.4%,凋亡指数均值为8.1%;生存素阴性组AI显著高于阳性组(P<0.01)。结论生存素选择性表达于膀胱癌中,通过抑制细胞凋亡,参与膀胱癌发生发展。     

生存素基因突变体诱导胃癌细胞凋亡的实验研究

目的 生存素(survivin)基因在胃癌组织中高水平表达，而在正常胃黏膜中无表达。生存素表达的水平与胃癌的预后密切相关。通过基因重组构建生存素基因突变体(pcDNA3—survivin—mutant，Cys84Ala)质粒，并以脂质体转染的方法将质粒DNA转入胃癌细胞株，观察其对胃癌细胞的生物学特性及多药耐药性的影响。方法 应用RT—PCR、Western blot、免疫组化等方法检测胃癌细胞中生存素基因mRNA和蛋白的表达，流式细胞仪和吖啶橙染色检测胃癌细胞凋亡。结果 通过RT—PCR检测，在所有的胃癌细胞株中均有不同程度生存素基因表达，生存素基因突变体Cys84Ala通过抑制野生型生存素基因的功能诱导胃癌细胞凋亡，增加caspase—3活性和促进细胞色素C的释放，增加胃癌细胞对化疗药物的敏感性。结论 突变体Cys84A1a能诱导胃癌细胞凋亡和增加胃癌细胞对化疗药物的敏感性。因此，生存素基因突变体Cys84Ala有可能成为胃癌治疗的一个候选基因。     

miR-506在人结肠癌羟基喜树碱多药耐药中的功能研究

目的探讨miR-506在人结肠癌羟基喜树碱多药耐药中的潜在作用。方法首先通过PCR从基因组DNA中克隆出包含miR-506前体的片段,将其连接至miRNA表达载体pMIF-cGFP-Zeo中,测序进行验证。将构建成功的pMIF-miR-506转染至低表达miR-506的亲本细胞SW1116中,加入含G418的选择性培养基进行选择性培养。运用RT-PCR验证稳定转染pMIF-miR-506的SW1116细胞株中的miR-506的表达情况,MTT法检测稳定转染pMIF-miR-506的SW1116细胞株和亲本细胞SW1116对羟基喜树碱的敏感性差异,Annexin V/PI检测各自对羟基喜树碱的凋亡情况。结果测序结果表明hsa-miR-506的前体序列被成功地构建至miRNA表达载体pMIF-cGFP-Zeo中。TaqMan荧光定量PCR技术检测发现,相比亲本细胞SW1116,稳定表达绿色荧光的SW1116细胞克隆中miR-506的含量显著升高,约为33.7±8.3倍。细胞增殖试验表明稳定转染pMIF-miR-506的SW1116细胞株的IC50为(280±13)μg/L,而对照组SW1116的IC50为(152±12)μg/L。同时还发现在相同浓度的羟基喜树碱作用下,亲本细胞SW1116较稳定转染pMIF-miR-506的SW1116细胞株的凋亡细胞比率增高(150μg/L:7.8%±1.7%vs5.4%±1.2%;300μg/L:33.6%±3.9%vs18.2%±4.7%)。结论成功地构建了过表达miR-506的载体pMIF-miR-506;过表达miR-506能够增加SW1116对羟基喜树碱的抵抗性。     

小鼠β-防御素2对结肠癌细胞增殖和凋亡的影响

目的探究小鼠β-防御素(mBD)2对结肠癌细胞SW480细胞增殖、凋亡作用及可能作用机制,为结肠癌的临床治疗提供新思路。方法体外培养SW480细胞,转染mBD2重组质粒分为空白组(Control组)、阴性转染组(NC组)、mBD2转染组,CCK8法检测细胞增殖情况;平板细胞克隆实验检测细胞克隆形成数目情况;Hoechst33342染色法观察细胞形态变化;流式细胞仪检测细胞凋亡及细胞周期情况;Western印迹法检测凋亡有关蛋白Bax、活化的含半胱氨酸的天冬氨酸蛋白水解酶(caspase)3、Bcl-2蛋白表达情况。结果随着细胞培养时间延长,mBD2转染组细胞增殖抑制率逐渐升高,在同一时间点,与Control、NC组相比,mBD2转染组细胞增殖抑制率显著升高(P0.05)。与Control、NC组相比,mBD2转染组细胞克隆形成数目均降低,mBD2转染组细胞凋亡率显著升高(P0.05)。与Control、NC组相比,mBD2转染组细胞G1期DNA量均显著升高(P0.05)。3组G2期、S期DNA量无明显变化(P0.05)。与Control、NC组相比,mBD2转染组细胞中Bax、活化caspase3蛋白表达均显著升高,Bcl-2蛋白表达显著降低(P0.05)。结论 mBD2可能通过使细胞阻滞于G1期,上调凋亡蛋白表达,进而抑制SW480细胞增殖,促进其凋亡,发挥抗肿瘤作用。     

Three layer functional model and energy exchange concept of aging process

Relying on a certain degree of abstraction, we can propose that no particular distinction exists between animate or living matter and inanimate matter. While focusing attention on some specifics, the dividing line between the two can be drawn. The most apparent distinction is in the level of structural and functional organization with the dissimilar streams of ‘energy flow’ between the observed entity and the surrounding environment. In essence, living matter is created from inanimate matter which is organized to contain internal intense energy processes and maintain lower intensity energy exchange processes with the environment. Taking internal and external energy processes into account, we contend in this paper that living matter can be referred to as matter of dissipative structure, with this structure assumed to be a common quality of all living creatures and living matter in general. Interruption of internal energy conversion processes and terminating the controlled energy exchange with the environment leads to degeneration of dissipative structure and reduction of the same to inanimate matter, (gas, liquid and/or solid inanimate substances), and ultimately what can be called ‘death.’ This concept of what we call dissipative nature can be extended from living organisms to social groups of animals, to mankind. An analogy based on the organization of matter provides a basis for a functional model of living entities. The models relies on the parallels among the three central structures of any cell (nucleus, cytoplasm and outer membrane) and the human body (central organs, body fluids along with the connective tissues, and external skin integument). This three-part structural organization may be observed almost universally in nature. It can be observed from the atomic structure to the planetary and intergalactic organizations. This similarity is corroborated by the membrane theory applied to living organisms. According to the energy nature of living matter and the proposed functional model, the decreased integrity of a human body's external envelope membrane is a first cause of the structural degradation and aging of the entire organism. The aging process than progresses externally to internally, as in single cell organisms, suggesting that much of the efforts towards the restoration and maintenance of the mechanisms responsible for structural development should be focused accordingly, on the membrane, i.e., the skin. Numerous reports indicate that all parts of the human body, like: bones, blood with blood vessels, muscles, skin, and so on, have some ability for restoration. Therefore, actual revival of not only aging tissue of the human body's membrane, but the entire human body enclosed within, with all internal organs, might be expected. We assess several aging theories within the context of our model and provide suggestions on how to activate the body's own anti-aging mechanisms and increase longevity. This paper presents some analogies and some distinctions that exist between the living dissipative structure matter and inanimate matter, discusses the aging process and proposes certain aging reversal solutions.     

Unusual responses of nocturnal pineal melatonin synthesis and secretion to swimming: Attempts to define mechanisms

Abstract: The effect of swimming at night on rat pineal melatonin synthesis was compared with that of light exposure at night. Rats were forced to swim at 0030 hr (lights out at 2000 hr) and sacrificed by decapitation 15 and 30 min later, immediately after swimming. Other groups of animals were exposed to white light (650μW/cm²) for 15 and 30 min at same time. Swimming caused a rapid and highly significant drop in the melatonin content in the pineal gland; however, the activity of N-acetyltransferase (NAT), the supposed rate limiting enzyme in the melatonin production, was not changed. Despite the drop in pineal melatonin levels, serum concentrations of the indole remained elevated in the rats that swam. In contrast, melatonin levels in the pineal and serum of light exposed rats fell precipitously, accompanied by a significant suppression of NAT activity. Since we anticipated that the strenuous exercise associated with swimming may induce release of artrial natriuretic peptide (ANP) from the heart, which in turn could cause the release of pineal melatonin, in a second study we injected physiological saline intravenously to stretch the cardiac muscle and release ANP. Three milliliters of normal saline was injected during the day into the jugular vein of anesthetized rats that were pretreated with isoproterenol to stimulate pineal melatonin production. Animals were killed 15 min after the saline injection, and pineal NAT activity and pineal melatonin levels were measured. The saline injections caused no alteration in the elevated levels of either NAT or melatonin. These data suggest that the disparity in pineal NAT activity (which was high) and pineal melatonin (which was low), in animals swum at night, may not be caused by ANP which is released during strenuous exercise such as swimming.     

Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep

Abstract: Well-established circadian physiology supports the view that photoperiodic time measurement utilizes the coincidence between the presence of light and a photosensitive phase of a 'biological clock' to alter reproductive status—the so-called external coincidence model of seasonal breeding. In this review, we examine the mechanism whereby photoperiod interacts with presumed suprachiasmatic nuclei activity to allow endogenous melatonin to normally synchronize reproductive activity to the optimal time of year. The Romney Marsh sheep is particularly explored as an experimental model. It is suggested that the on/off activity of seasonal reproduction may be a robust mechanism able to be predictably manipulated by the judicious use of the light/dark cycle and exogenous melatonin, but firmly based on circadian principles.     

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.     

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.     

Serological survey of HIV and syphilis in pregnant women in Madagascar

Objectives Peripartal transmission of human immunodeficiency virus (HIV) and Treponema pallidum, the causative agent of syphilis, leads to severe consequences for newborns. Preventive measures require awareness of the maternal infection. Although HIV and syphilis testing in Madagascar could be theoretically carried out within the framework of the national pregnancy follow‐up scheme, the required test kits are rarely available at peripheral health centres. In this study, we screened blood samples of pregnant Madagascan women for HIV and syphilis seroprevalence to estimate the demand for systemic screening in pregnancy. Methods Retrospective anonymous serological analysis for HIV and syphilis was performed in plasma samples from 1232 pregnant women that were taken between May and July 2010 in Ambositra, Ifanadiana, Manakara, Mananjary, Moramanga and Tsiroanomandidy (Madagascar) during pregnancy follow‐up. Screening was based on Treponema pallidum haemagglutination tests for syphilis and rapid tests for HIV, with confirmation of positive screening results on line assays. Results Out of 1232 pregnant women, none were seropositive for HIV and 37 (3%) were seropositive for Treponema pallidum. Conclusions Our findings are in line with previous studies that describe considerable syphilis prevalence in the rural Madagascan population. The results suggest a need for screening to prevent peripartal Treponema pallidum transmission, while HIV is still rare. If they are known, Treponema pallidum infections can be easily, safely and inexpensively treated even in pregnancy to reduce the risk of transmission.     

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.     

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.