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关键词： organizational   epigen   embryonic stem cell   Laboratory mice  

摘要： Changes in nuclear organization and the epigenetic state of the genome are important driving forces for developmental gene expression. However, a strategy that allows simultaneous visualization of the dynamics of the epigenomic state and nuclear structure has been lacking to date. We established an experimental system to observe global DNA methylation in living mouse embryonic stem (ES) cells. The methylated DNA binding domain (MBD) and the nuclear localization signal (nls) sequence coding for human methyl CpG-binding domain protein 1 (MBD1) were fused to the enhanced green fluorescent protein (EGFP) reporter gene, and ES cell lines carrying the construct (EGFP-MBD-nls) were established. The EGFP-MBD-nls protein was used to follow DNA methylation in situ under physiological conditions. We also monitored the formation and rearrangement of methylated heterochromatin using EGFP-MBD-nls. Pluripotent mouse ES cells showed unique nuclear organization in that methylated centromeric heterochromatin coalesced to form large clusters around the nucleoli. Upon differentiation, the organization of these heterochromatin clusters changed dramatically. Time-lapse microscopy successfully captured a moment of dramatic change in chromosome positioning during the transition between two differentiation stages. Thus, this experimental system should facilitate studies focusing on relationships between nuclear organization, epigenetic status and cell differentiation.

关键词： CORONARY heart disease   ANOXEMIA   HEART failure   EMBRYOLOGY   HEART septum   NEOVASCULARIZATION  

摘要： In our previous studies we found that quail embryos incubated under hypoxic conditions (16 % 02) die at embryonic day (ED) 9 with signs of heart failure. By ED 4 and 6 we found thinner ventricular wall and increased capillary density. We thus hypothesized that the cause of death would lie in severe coronary maldevelopment. We analyzed serial histological sections of normoxic and hypoxic hearts from ED 6, 7, 8, and 9. In ED 6 and 7 hypoxic hearts we found thinner wall in all compartments, especially the left ventricle. Simultaneously we found an increase in capillary density in interventricular septum. This site corresponds to an area of tissue hypoxia and ensuing increased angiogenesis. In sections from ED 9 hypoxic hearts we found irregularities in development of coronary tree (missing coronary ostia, absence of one coronary artery, and thinner arterial wall). By injection of ink through the left ventricle to the coronary arteries we found in normoxic specimens regular coronary branching pattern, while in the hypoxic ones there was only irregular plexus. In conclusion, hypoxia leads to increased capilarization and trabecularization to minimize diffusion distance. In the subsequent period there is a failure in organization of vascular plexus into normal vasculature, leading to heart failure and embryonic death. [ABSTRACT FROM AUTHOR]

关键词： 磷脂酶C-γ1   胚胎肾组织   免疫细胞化学   Western   blot技术  

摘要： 目的:研究磷脂酶C-γ1(PLC-γ1)在小鼠胚胎肾组织中的表达,探讨其临床意义。方法:制备小鼠胚胎肾组织标本,进行石蜡包埋并切片,采用免疫细胞化学方法检测PLC-γ1的表达情况,并进一步利用Western blot技术对磷脂酶C-γ1的表达进行初步定量。结果:免疫细胞化学结果表明,PLC-γ1在小鼠胚胎肾组织中的集合管上皮细胞游离面阳性反应较强,而周围的肾小球、肾小囊、肾小管等为阴性反应。在胚胎第18、16天的肾切片中,集合管反应仍呈现弱阳性,在胚胎第14天的肾切片中,集合管上皮呈现较强阳性反应。Western blot结果表明,PLC-γ1在胚胎第14、16、18天的表达量逐渐降低。结论:PLC-γ1相关的信号通路对于小鼠胚胎肾的发育,尤其是早、中期发育,具有重要的生物学作用。

关键词： 深低温   胚胎脊髓   移植  

摘要： 目的:胚胎细胞脊髓内移植是判定冻存细胞最直接的证据。通过计算机图像处理系统判定细胞核质比例,以观察经深低温保存后大鼠胚胎脊髓细胞形态和存活率的变化。方法:实验于2004-12/2005-03在承德医学院临床技能实验室完成。剖腹取胎龄14d Wistar大鼠的胎鼠,分离胚胎脊髓,剪成1mm3的小块。将DMEM细胞培养液70mL、大鼠灭活血清20mL、DMSO10mL混合制成冻存液。取冻存管,加入冻存液10mL,并将剪好的胚胎脊髓组织10～20块放入其中,封口。放于冰箱中逐步降温保存,最后置于液氮中保存。胚胎脊髓在液氮中保存15d后,取出冻存管,放入37℃恒温水浴槽中快速复温,待完全融化后,以3000r/min离心3min,弃去上清液,再加入等量DMEM细胞培养液,静置3min,冲洗,并植入正常大鼠脊髓内。以台盼蓝拒染率测定深低温保存前和深低温保存后胚胎脊髓组织细胞存活率,着色的为死亡细胞、不着色的为存活细胞。算出细胞存活率和核质比例。4周后应用免疫组化法检测受体大鼠移植段脊髓。结果:①经低温保存的胚胎脊髓细胞存活率低于未经低温保存组[(64.78±6.14)%,(50.07±7.58)%,P<0.01];两组的存活细胞形态和核质比无明显改变。②移植后4周,有1只大鼠因感染死亡。镜下观察移植大鼠脊髓组织均可见移植物存活,存活移植物与受体脊髓组织融合良好,移植区边缘均有少量宿主神经细胞空泡变性,2只因移植物与受体之间存在裂隙,只有部分融合,无明显胶质瘢痕,1只移植区外偶见局限淋巴细胞浸润。③免疫组化检测显示,在移植区内可见少量的5羟色胺及神经丝阳性细胞和纤维,在损伤腔边缘部可见大量来自宿主的5-羟色胺阳性纤维进入移植区,移植区周边的纤维较中央部位纤维粗大。结论:经过深低温保存大鼠胚胎脊髓组织保持了原有的细胞形态,并能够在异体脊髓内存活,并与宿主融合良好,保持了原有的活性。

关键词： 组织学与胚胎学   双语教学   教学模式  

摘要： 目的:针对组织学与胚胎学的学科特点及双语教学的自身特点,对影响教学效果的各因素进行分析研究,探讨科学有效的七年制组织学与胚胎学双语教学模式。方法:对2004-2005学年第1学期合班理论授课的七年制3个班级发放不同模式的理论授课纲要,采用不同的实验教学方式,通过期末考试成绩及问卷调查结果,对教学效果进行比较分析。结果:在50%以上英文理论授课的前提下,实验教学模式一(对比启发式教学、全英文讲授、英文提问、英文实验报告)取得了较好的教学效果;大部分同学认为课前发放授课纲要有利于提高课堂听课效果,而针对专业词汇的英汉互译模式是学生理想的幻灯及授课纲要模式。结论:有效的实验教学及一定的辅助教学手段对组织胚胎学双语教学效果起着至关重要的作用。

关键词： 组织学与胚胎学   实验教学   教学改革  

摘要： 21世纪是医学飞速发展的时代,为了培养出适应时代需要的医学生,组织胚胎学实验教学进行了初步改革,包括以下四方面：实验内容;改编组织胚胎学实验指导书;引进现代电教媒体（数码互动系统）;改革实验考核形式。

关键词： SCI   解剖学   形态学   源期刊  

摘要： 目的:对SC I及SC I-E收录人体解剖学及组织胚胎学期刊做一介绍,为相关科研工作者参阅及发表高质量文章提供参考。方法:对SC I及SC I-E按主题分类进行检索,使用JCR数据库影响因子排序列举2005年最具影响力的期刊。结果:2006年SC I-E收录的期刊共16种,其中SC I收录11种。并按影响因子列举了排名前13位期刊的基本信息。结论:SC I及SC I-E对所收录期刊进行严格审核,其收录期刊足以反映各学科最新研究进展。

关键词： embryonic cell death   cathepsin D   limb development   heart development  

摘要： The implication of lysosomes in the activation of physiological cell death (PCD) was proposed some decades ago. In this work, we show that the expression of the lysosomal enzyme cathepsin D is up-regulated in developing tissues undergoing apoptosis. By comparing vital and terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling (TUNEL) labeling patterns with in situ hybridization for this gene in a variety of tissues and organs, we show that this procedure constitutes a reliable technique to map the regions of PCD in the embryo. Using this methodological approach, we report the occurrence of two new areas of PCD in the developing limb.

关键词： Drosophila   blastoderm   microfilaments   microtubules  

摘要： Dynamic alterations in the spatial organization of cytoskeletal elements constitute a prominent morphological feature of the early, syncytial stages of embryogenesis in Drosophila. Here, we describe and characterize the dynamic behavior of cytoplasmic, subcortical microfilaments, which form a series of nucleus-associated structures, at different phases of the simultaneous nuclear division cycles characteristic of early Drosophila embryos. Remodeling of the cytoplasmic microfilament arrays takes place in parallel to the established cyclic reorganization of cortical microfilament structures. We provide evidence that the cortical and subcortical microfilament populations organize independently of each other, and in response to distinct instructive cues. Specifically, formation of subcortical microfilament structures appears to rely on, and spatially mirror, the organization of polarized microtubule arrays, while cortical microfilament restructuring constitutes a centrosome-dependent process. Genetic analysis identifies a requirement for SCAR, a key mediator of Arp2/3-based microfilament dynamics, in organization of subcortical microfilament structures.

关键词： embryogenesis   histology   hybridization   incompatibility barriers   suspensor  

摘要： In this paper, the causes of early embryo abortion in the reciprocal crosses between Phaseolus vulgaris L. (a cultivar) and Phaseolus coccineus L. (a wild form) were studied. Methacrylate resin sections, 3-5 mu m thick, of 3 to 14 day-old seeds were used to examine the embryo developmental stages and the state of seed tissue. It was observed that, embryos aborted at different developmental stages (globular to early cotyledon) depending on the maternal parent. The use of P. coccineus cytoplasm resulted in a higher number of abortion than in reciprocal crosses. Many of them took place between 5 and 6 days after pollination (DAP). Histological analyses permitted to observe that the embryo development was slower in the cross between P. coccineus and P. vulgaris, compared to parental seeds. It would be related to a deficient endosperm development in reciprocal crosses and, in some extent, hypertrophy of the suspensor might be the main cause of early embryo abortion. Then, it would be practical to overcome this incompatibility by rescuing the embryo at the globular stage of development.