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关键词： coconut   Cocos nucifera L.   somatic embryogenesis   abscisic acid  

摘要： Somatic embryogenesis in coconut (Cocos nucifera L.) is generally induced by gradual reduction of auxin concentration in the culture medium and incorporation of cytokinins. Although plant regeneration through somatic embryogenesis is possible, the protocol is yet to be perfected. In this study, nodular callus was obtained from 7-9 months old immature zygotic embryos of coconut on a medium containing 24 mu M 2,4-dichlorophenoxy acetic acid (2,4-D). As a novel approach, abscisic acid (ABA) at a concentration of 2.5-7.5 mu M was incorporated into the culture medium for 3-7 weeks to induce somatic embryogenesis. Alternately, callus was subcultured at 5 weekly intervals on media containing gradually reducing concentrations of 2,4-D to induce somatic embryogenesis. Incorporation of ABA enhanced the production of somatic embryos. Application of 2.5-5 mu M ABA for 5 weeks was found to be effective. A large number of somatic embryos developed on media containing ABA formed normal shoots and complete plants as compared to those produced in the media with low levels of 2,4-D. (C) 2000 Published by Elsevier Science Ireland Ltd. All rights reserved.

关键词： Powerpoint   组织胚胎学   医学教育  

摘要： 组织胚胎学是一门重要的医学基础课程,其教学特点是需要大量图象、模型来说明和展示细胞、组织和器官的细微结构与功能的关系,其内容相对固定又抽象枯燥,缺乏相互联系,因而教学难度较大,学生的疑难点较多.在教学改革不断深入的今天,在较少的课时内展示组织胚胎学丰富的内容,传统的教学媒体显然已不能适应其教学需要.为此,我们尝试将Powerpoint软件教学应用在98级临床医学系本科的组织胚胎学理论课中,并取得了理想的效果.

关键词： 生物全息律   病邪进入人体   脏腑辨证   五脏   《内经》   组织胚胎学   脏层   辨证论治   外感咳嗽   内伤杂病  

摘要： 历代中医对疾病的辨证都很重视病邪进入人体的不同部位和层次。如伤寒病以三阴三阳为层次,按照寒邪耗伤人体阳气的程度来划分疾病的不同类型及阶段;温病以卫气营血分四个层次,按照温热邪气伤人体之阴的多少确定病情的轻重缓急;内伤杂病一般选用脏腑辨证,用五脏定位,气血阴阳寒热痰淤概括疾病的本质。那么,每一脏器的病变过程,是否也存在层次的差异,五脏除体内不同空间的概念是否也有层次的含义?

关键词： 枸杞   髓组织培养   体细胞胚胎   过氧化物酶   同工酶  

摘要： 枸杞髓组织在 MS+6 - BA0 .1mg/ L+NAA0 .5mg/ L培养基上诱导愈伤组织发生。在 MS+6 - BA0 .1mg/ L+NAA0 .5mg/ L+CH50 0 mg/ L培养基上继代培养 ,再转入 MS+6 - BA2 mg/L +NAA 0 .5mg/ L的分化培养基上进行分化培养。显微观察表明 ,在培养过程中愈伤组织细胞由非胚性细胞转变为胚性细胞 ,直至发育成体细胞胚胎和完整植株 ;电泳结果显示 ,体细胞胚胎发生的各阶段 ,其过氧化物酶同工酶发生相应的变化。

关键词： 组织胚胎学   医学教育   说课   应用  

关键词： 〈,人体解剖学与组织胚胎学》   教材   综合评估  

摘要： 本文以教材质量的“水平一因素一等级”评价体系和等级分值为基础，综合评估由教师和学生构成的三个统计样本对《人体解剖学乌组织胚胎学》教材的质量水平。结果表明，此教材的质量符合教学大纲的要求和医学专科教学的需要，但更适合统招医学专科学生的教学要求。为了全面反映和衡量教材质量水平，建议将专家评价和学生评价同时作为教材质量评价的主渠道。

关键词： 医学教学   解剖学   组织胚胎学   多媒体教学   教学  

摘要： 《人体解剖及组织胚胎学》是医学生学习过程中最早接触到的一门基础课程 ,传统的教学方法一直以语言描述和标本实习为主 ,并辅以幻灯投影等手段。但随着新大纲、新计划的实施 ,课时减少 ,仅仅依赖传统方法教学显得愈来愈困难。我校 1997年建立了现代化的多媒体电教室 ,为多媒体教学创造了极佳的教学环境与条件。作者将多媒体教学应用到所授课的二个班级 ,配合目标教学的实践 ,选择适当的内容和方式 ,精心组织课程 ,取得了良好的效果。1　教学资源的选择和教学方法的实施1 1　教学资料片源的选择 :以满足中等卫生学校《解剖学及组织胚胎学》教学的需要为原则。首先 ,在具备多媒体教学硬件的前提下 ,要选择适当的软件片源。我们选择了北京双语教学电子有限公司制作、华中理工大学出版社出版的《双语 3Ｄ人体百科探秘》多媒体光盘作教学片。该光盘将人体的结构知识 ,建立全三维仿真操作系统 ,动画形象生动 ,色泽丰富 ,解说清晰准确 ,由浅入深 ,环环相扣。由人体机器、3Ｄ透视、Ｘ光透视等几个部分构成。相互之间既可独立操作 ,又可以重叠加影 ,以最直观的形式展示复杂的知识体系 ,完全可以满足中专教学需要 ,使用效果良好。其次 ,是对教学内容的...

关键词： 青光眼   视网膜   眼表疾病   胚胎干细胞   组织工程  

摘要： 当前视觉科学研究领域及眼科临床所存在的主要难题包括青光眼、视网膜黄斑疾病等的视功能保护和治疗以及缺乏适当组织配型的移植材料治疗眼表疾病等问题,胚胎干细胞与组织工程学研究的进展,为解决这些问题提供了具有较大发展潜力的新途径,本文就该研究领域现况及前景作一综述,以飨读者。眼科学报2000;16:118-123。

关键词： cell lineage   cell migration   posterior mesenchyme cell pattern   2D-embryo  

摘要： Primary mesenchyme cell (PMC) migration during PMC-ring pattern formation was analyzed using computer-assisted time-lapse video microscopy in spread embryos (2D-embryo) of the sea urchin, Mespilia globulus, and a computer simulation. The PMC formed a near normal ring pattern in the 2D-embryos, which were shown to be an excellent model for the examination of cell behavior in vivo by time-lapse computer analysis. The average migration distance of the ventro-lateral PMC aggregate-forming cells (AFC) and that of the dorso-ventral PMC cable-forming cells (CFC) showed no significant difference. All PMC took a rather straightforward migration path to their destinations with little lag time after ingression. This in vivo cell behavior fitted well to a computer simulation with a non-diffusable chemotaxis factor in the cyber-cell migration field. This simulation suggests that PMC recognize their destination from a very early moment of cell migration from the vegetal plate, and implicates that a chemoattractive region is necessary for making the PMC migration pattern. The left- and right-lateral AFC and dorso and ventral CFC were each derived from an unequally divided one-quarter segment of the vegetal plate. This suggests that AFC and CFC have a distinctive ancestor in the vegetal plate, and the PMC are a heterogeneous population at least in terms of their destination in the PMC-ring pattern.

关键词： microwave fixation   odontoblasts   ameloblasts   mineralisation   ultrastructure   extracellular matrix  

摘要： Adequate preservation of the cells and matrix of mineralising tissues remains difficult, as organic components and initial mineral deposits may be lost during conventional processing for electron microscopy. In this study, we have reduced significantly the processing time using microwave irradiation. Rat molar tooth germs were fixed in 4% glutaraldehyde +4% formaldehyde with 0.1 M sodium cacodylate in a laboratory microwave oven for two periods of 20 s with a maximal temperature of 37 degrees C. After conventional washing and post-fixation. specimens were dehydrated in graded ethanols under microwave irradiation for a total of 7 min 20 s. For comparison, some specimens were processed by conventional methods. After embedding, ultrathin sections were examined by electron microscopy. In differentiating ameloblasts and odontoblasts, plasma membranes, mitochondria, rough endoplasmic reticulum, the Golgi complex, together with all other cytoplasmic organelles exhibited excellent preservation. Microtubules, microfilaments and coated vesicles were particularly evident. Crystal-like mineral deposits were conspicuously present in relation to dentine matrix vesicles and collagen fibrils as well as in enamel matrix. The matrix of forming enamel had a globular electron-lucent appearance. It is concluded that this is a rapid method which provides a preserved or even improved morphology.