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关键词： 人胚胎   骨发育   哈佛氏系统   股骨  

摘要： 目的　探讨人胚胎长骨的发生及发育过程。方法　取第 9～ 38周人胚胎股骨 ,用HE、硫堇 -苦味酸及Mallory氏法染色 ,光镜观察。结果　第 9周胚胎股骨为软骨雏形。第 10～ 38周胚胎股骨可分出骺软骨、干骺端及骨干三部分 ,干骺端原始骨髓腔内富含血管、成骨细胞及造血细胞 ,成骨细胞与造血细胞的比例随胎龄而异 ,第 2 0周以前 ,以成骨细胞为主 ,造血细胞极少 ,随胎龄增加 ,成骨细胞的比例逐渐下降 ,造血细胞增加 ;骨干表面不光滑 ,有许多纵嵴、纵沟 ,骨外膜内层覆于嵴上并衬于沟内 ,纵嵴纵沟以第 13～ 2 6周胚胎为多 ,第 2 7周以后逐渐减少 ,骨干表面逐渐变得光滑 ,足月时出现外环骨板 ;骨干皮质由骨小梁网构成 ,胚胎早期网眼大、不规则 ,随胎龄增加 ,网眼变小 ,周围出现分层不清的同心圆状排列的骨板。结论　人胚胎长骨的纵向生长速率随胎龄的增加而相对减慢 ,其横向生长是由于骨外膜内层的成骨细胞以形成纵嵴的方式 ,不断地在骨干表面添加新的骨质 。

关键词： 6-OHDA-induced hemiparkinsonism   embryonic nerve tissue transplantation   dopamine  

摘要： Effect of transplantation of embryonic ventral mesencephalon preparation containing dopaminergic neurons on repair of the dopaminergic nigrostriatal system was studied in rats with hemiparkinsonism induced by 6-hydroxydopamine, Transplantation of embryonic ventral mesencephalon into denervated striatum led to a more than 50% decrease in apomorphine-induced rotation, recovery of dopamine and DOPAC levels in the brain, and to an increase in DOPAC excretion and the DOPAC-dopamine ratio in daily urine of rats with hemiparkinsonism. Dopaminergic neurons of the transplant survived, forming a network of tyrosine hydroxylase-positive processes growing beyond the transplant and reinnervating the adjacent compartments of the striatum. A positive correlation between urinary excretion of DOPAC and brain concentration of dopamine was revealed in denervated rats after transplantation of ventral mesencephalon. Intrastriatal transplantation of cell preparations of embryonic striatum containing no dopaminergic neurons and isolated local injury to the striatum did not affect regeneration of the denervated nigrostratal system.

关键词： Body Patterning   Intercellular Signaling Peptides and Proteins   Amino Acid Sequence   Animals   Glycoproteins   Molecular Sequence Data   Research Support   Non-U.S. Gov't   Research Support   U.S. Gov't   P.H.S.   Sequence Homology   Amino Acid   Vertebrates  

摘要： Molecular studies have begun to unravel the sequential cell-cell signalling events that establish the dorsal-ventral, or 'back-to-belly', axis of vertebrate animals. In Xenopus and zebrafish, these events start with the movement of membrane vesicles associated with dorsal determinants. This mediates the induction of mesoderm by generating gradients of growth factors. Dorsal mesoderm then becomes a signalling centre, the Spemann's organizer, which secretes several antagonists of growth-factor signalling. Recent studies have led to new models for the regulation of cell-cell signalling during development, which may also apply to the homeostasis of adult tissues.

关键词： Cajal-Retzius cells   cortical development   hamster   neuronal migration   radial glia  

摘要： In this study,we show that the radial migration of neuronal precursors out of cerebral cortex of embryonic brain slices cultured for 4-7days gives rise to an organized tissue that forms de novo off developing slices. In our in vitro preparations, migrating neuronal precursors overshot the marginal zone, as did the elongation of radial glial processes out of the slices. These cells detached from radial glia at a distance from the cortex and differentiated into pyramidal and nonpyramidal profiles that expressed different neuronal markers. Glial precursors were shown to proliferate in the slice and in the neotissue, and to differentiate into astrocytes. We show that cells expressing reelin in the marginal zone of embryonic cortical slices persist after a week in culture, which implies that neuronal migration is not necessarily hindered by the presumed stop signals provided by reelin in the marginal zone. Furthermore, our results provide a new model for in vitro studies of migration and differentiation during cortical development.

关键词： 卫生管理专业   组织胚胎学   教学改革  

关键词： 组织学   胚胎学   教学   医学教育  

摘要： 医学的迅猛发展对医学生的素质提出更高的要求 ,不断提高教学质量是每一位教师的基本义务。《组胚学》是医学教育的重要入门课程之一 ,它为其它医学基础课程 (生理学、病理学等 )和临床课程 (如内科学、妇产科学等 )的学习奠定坚实的基础。这里笔者浅谈教学中的几点体会。1　充分发挥学生学习的主动性组胚学作为一门形态学 ,教学内容存在大量形态描述 ,学生容易觉得枯燥乏味 ,并易混淆难以记忆。组织学是微观上的解剖学 ,肉眼看不见 ,摸不着 ,切片与照片呈现的是平面图像 ,但人体结构是立体的 ,这就要求学生必须学会通过平面图像理解立体结构。胚胎学更是多个“变”字 ,在不同时期 ,个体发生的结构变化极其复杂。这些特点都增加了组胚学的学习难度。而这门学科授课对象为大学一年级学生 ,大部分学生还没有完成从中学生到大学生的角色转变。多年来 ,学生普遍认为本学科抽象难懂。作为教师除了注意改进教学方法、吸引学生外 ,促进学生尽快完成角色转变尤为重要。要让学生对学习中遇到的困难有足够的心理准备。在一开始学习就告诉学生 ,大学里的学习内容要比中学的深奥 ,一些纯理论的内容会比较枯燥 ,不可能期望老师把所有内容讲得象故事一样引人入胜 ,而自...

关键词： 芳香化酶P450   肺肿瘤   胚胎肺   mRNA  

摘要： 芳香化酶P450,作为催化雄激素转化为雌激素的限速酶,对胎儿性别的分化、中枢神经系统的生长发育和内分泌起着重要的调节作用[1].近几年发现它在雌激素依赖性肿瘤如乳腺癌、子宫癌等的发生发展中也起着重要的作用[2,3].但芳香化酶在肺癌组织中有无表达国内外尚未见有关报道.本研究采用原位杂交检测肺癌、胚胎肺以及肺良性病变组织中芳香化酶mRNA的表达,旨在探讨芳香化酶mRNA在肺癌以及胚胎肺组织中的定位、分布情况及其意义,结果报告如下.

关键词： cell lineage   central nervous system   clonal analysis   laacZ   postnatal mouse   neural tube   spinal cord  

摘要： We have used the LaacZ clonal method of cell labeling of neuronal ancestors and report that the spatial organization of neuronal cells in the post-natal CNS shares striking similarities to that in the embryonic neuroepithelium, from the spinal cord to the diencephalon. The maintenance of the organization occurs despite massive cell divisions and morphogenetic movements. We deduce that the cellular and architectural organization in the mouse CNS results from a succession of patterns of oriented cell dispersion, a general arrest of cell dispersion in the neuroepithelium, and then well-documented radial neuronal migration. The arrest of cell dispersion in the neuroepithelium is consistent with the possibility that an important part of the cellular and architectural organization of the mature CNS requires conservation of spatial relationship between cells and supports the hypothesis of a transition from global and sparse to local and dense cell interactions occuring early within the neuroepithelium, (C) 2000 Wiley-Liss, Inc.

关键词： Mdm2   p53   zebrafish   development   oncogenesis  

摘要： The Mdm2 protein is most probably the main negative cellular regulator of the p53 turner-suppressor protein. It was found to be overexpressed in a great number of human tumors and is considered as a potential target for anti-tumor therapies. Mdm2 is an essential gene in mice, yet its role in normal development and tissue differentiation is unknown. In order to study the role of this important protein in an evolutionary perspective, we cloned atl Mdm2 cDNA from the fish Danio rerio and analyzed its expression pattern as well as the phenotypic consequences of its overexpression. The main functional domains as well as the interaction between Mdm2 and p53 are conserved in zebrafish. Moreover, we show here that the gene is expressed specifically during early development in neural and muscular tissues. Surprisingly, microinjection of Mdm2 mRNA in two-cell-stage embryos led to inhibition of cellular convergence during gastrulation. The clones derived from Mdma microinjected blastomeres were significantly smaller than those derived from control microinjections, and, in contrast to what was observed in Xenopus, did not develop tumors. Our results suggest that Mdm2 expression may be important during the differentiation of neural and muscular tissues of zebrafish. They also point to important differences between phyla in the susceptibility to tumor formation.

关键词： pamlin   primary mesenchyme   protein tyrosine kinase   SUp62   tyrosine phosphorylation  

摘要： Ingression of primary mesenchyme cells (PMC) is associated with the encounter of basal lamina including pamlin. it was found that sea urchin embryos have a protein that binds antihuman local adhesion kinase (FAK) antibodies, yet it has a 62 kDa homo-dimeric structure. Thus, this protein was distinctive from known FAK, and was named SUp62. In mesenchyme blastulae, one of the subunits increased its apparent. molecular mass slightly but distinctively then restored the original molecular mass in early gastrulae. This temporal and stage-specific shifting of the molecular mass was associated with the occurrence of tyrosine phosphorylation of a subunit that did not increase the apparent molecular mass. Herbimycin A induced the hyperphosphorylation of tyrosine residues of SUp62, and inhibited the occurrence of molecular mass shifting. Immunohistochemistry showed a strong positive signal of SUp62 and phosphotyrosine in PMC. Herbimycin A also severely but reversibly inhibited PMC dissociation, migration and gastrulation. Tyrosine phosphorylation of SUp62 was induced when PMC were incubated with pamlin in vitro, and it was initiated within 10 min after onset of the incubation. It reached its peak in 1 h, and declined gradually in the next 1 h, indicating that pamlin-induced tyrosine phosphorylation of SUp62 occurs closely associated with acquiring PMC migration activity.