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Pluripotential embryonic stem cells (ESC) possess a unique property of being able to carry out nuclear reprogramming of somatic nuclei, as shown after cell fusion. The nuclear reprogramming activity has been applied for producing pluripotential stem cells from personal somatic cells through several new technologies, including cytoplasmic cell fusion and ES cell factor introduction. Targeted elimination of ESC-derived chromosome(s) following cell fusion-mediated reprogramming of somatic chromosomes is one of the new technologies for producing personalized stem cells. A universal chromosome elimination cassette (CEC) has been developed that confers drug resistance and GFP (green fluorescent protein) fluorescence, flanked by oppositely orientated loxP sites, to induce sister chromatid recombination and targeted chromosome loss. GFP-positive ESC generated with a CEC-integrated chromosome were hybridized with adult thymocytes and then exposed to Cre recombinase. This led to loss of GFP expression and elimination of the CEC-tagged chromosome. Targeted elimination of a pair of ESC-derived chromosome 6s, which are key chromosomes for maintaining pluripotency, demonstrated that the reprogrammed somatic factors are sufficient for the continued pluripotentiality of hybrid cells. Targeted chromosome elimination technology therefore offers a means for developing major histocompatibility complex-personalized or completely personalized pluripotential stem cell populations for use in a range of therapeutic applications.  相似文献   

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Risk taking behaviors show attempts to escape from suffering, to struggle to live. They are different for boys and girls. Girls take suffering upon themselves and make of their bodies the very scene of that suffering, whereas boys throw themselves against the world in provocative, transgressive behaviours. Besides, when the will of the girl is to be unique, the will of the boy is to be the best.  相似文献   

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Tulandi T  Platt R 《Fertility and sterility》2004,81(1):11-2; discussion 18
The standard questionnaire is a tool to collect information for a survey, but its validity for patient management is doubtful. Taking a history is a skill that cannot be replaced by a questionnaire.  相似文献   

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支气管肺发育不良是早产儿常见的慢性呼吸系统并发症,其发病机制尚未完全阐明,且暂无有效防治措施,严重影响早产儿存活率及预后。已有研究证实,组蛋白修饰、非编码RNA和DNA甲基化等表观遗传学机制在支气管肺发育不良的发生、发展过程中发挥重要作用,且相关表观遗传变化多为可逆性改变,可能为临床治疗提供重要靶点。因此,表观遗传学研究将为进一步认识支气管肺发育不良的发病机制及防治支气管肺发育不良提供新方向和思路。  相似文献   

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As recent reports question the safety of some maternity services and of the accuracy of identifying risk factors in midwifery practice, this article advocates the use of 'fresh eyes' reviews of our own practice, that of our peers and the practice within our organisations. If, as the literature indicates, there is no evidence of sustained transformational change through compliance as opposed to commitment, then our engagement and motivation to adopt 'fresh eyes' approaches to our practice, may lead to improved patient outcomes, including rates of mortality.  相似文献   

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The vulvovaginal candidiasis represents, after the bacterial vaginosis, the most frequent cause of vaginal affection. It is esteemed that around the 75% of the women of reproductive age suffered from an episode of vulvovaginitis from candida and 40-45% have had more episodes, of which 10-20% in complicated form. The kind of candida more frequently isolated in the vagina of symptomatic women is the Candida albicans: in the 10-20% of the cases the agent is present in absence of symptomatology, and we can almost consider it a saprophytic. On the other hand, always with greater frequency fetterses can be isolated of not albicans Candida, particularly the tropicalis and the glabrata kind, usually resistant to the common therapies. The classification of the vulvovaginal candidiasis proposed by Sobel, and by now universally approved, foresees 2 clinical forms of vulvovaginal candidiasis, the vulvovaginitis from not complicated candida (VVC) and the vulvovaginitis from complicated candida (VVCC): different for pathogenesis, elapsed clinical, symptomatology and frequency. They have to be considered in the substance 2 different nosological entities, and they request a diagnostic approach and a well different therapeutic appointment. In this study we will shortly reassume the principal characteristics of it, detaining us on the most recent acquisitions in theme of therapy. The base medicines of ac. boric, to parity of effectiveness, seem to introduce the most contained cost and the best compliance, and they offer him to a complementary use or, in some cases, alternative to the more you consolidate therapies with azoli.  相似文献   

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Doppler Ultrasound allows the in vivo study of feto-placental hemodynamics. Doppler flow velocity waveforms (FVW's) obtained from the umbilical arteries reflect downstream blood flow impedance, thus giving indirect evidence of vascular villous tree characteristics. Pulsatility Index, which quantifies FVW's, decreases throughout normal pregnancy, indicating decreasing impedance and is often higher in cases of fetal growth restriction (FGR). Different approaches (morphometrical, morphological, mathematical, immunohistochemical and molecular) have contributed to elucidation of which anomalies of the vascular villous tree underlie Doppler findings. 3D ultrasound may be useful in the study of feto-placental perfusion. However, the unsolved question is why developmental villous tree anomalies occur. Crucial to the success of future research is definition of the population studied based on the uniform and correct definition of FGR.  相似文献   

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In multicellular organisms, germ cells are an extremely specialized cell type with the vital function of transmitting genetic information across generations. In this respect, they are responsible for the perpetuity of species, and are separated from somatic lineages at each generation. Interestingly, in the past two decades research has shown that germ cells have the potential to proceed along two distinct pathways: gametogenesis or pluripotency. Unequivocally, the primary role of germ cells is to produce gametes, the sperm or oocyte, to produce offspring. However, under specific conditions germ cells can become pluripotent, as shown by teratoma formation in vivo or cell culture-induced reprogramming in vitro. This phenomenon seems to be a general propensity of germ cells, irrespective of developmental phase. Recent attempts at cellular reprogramming have resulted in the generation of induced pluripotent stem cells (iPSCs). In iPSCs, the intracellular molecular networks instructing pluripotency have been activated and override the exclusively somatic cell programs that existed. Because the generation of iPSCs is highly artificial and depends on gene transduction, whether the resulting machinery reflects any physiological cell-intrinsic programs is open to question. In contrast, germ cells can spontaneously shift their fate to pluripotency during in-vitro culture. Here, we review the two fates of germ cells, i.e., differentiation and reprogramming. Understanding the molecular mechanisms regulating differentiation versus reprogramming would provide invaluable insight into understanding the mechanisms of cellular reprogramming that generate iPSCs.  相似文献   

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