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关键词： PBL教学模式   组织胚胎学   教学效果   实验课   系统   医学基础课程   数   微细结构  

摘要： 组织胚胎学是一门重要的医学基础课程，属于形态学范畴，主要研究机体的微细结构、相关功能以及人体胚胎的发生发育过程。实验课的直观教学是该学科的重要组成部分，学生对组织切片的良好认知将有助于其对理论知识的理解和记忆。为了改善实验教学条件，创造良好的教学环境，我校首次将数码显微互动系统运用到组织胚胎实验教学中，将传统的组织胚胎学实验教室变成多媒体互动网络教室，并对实验课的教学模式进行了改进，开展PBL教学模式，取得了较好的教学效果。

关键词： MICROTUBULES   CYTOKINESIS   GERMPLASM resources   CELL division (Biology)   GERM cells  

摘要： Microtubule-microfilament interactions are important for cytokinesis and subcellular localization of proteins and mRNAs. In the early zebrafish embryo, astral microtubule-microfilament interactions also facilitate a stereotypic segregation pattern of germ plasm ribonucleoparticles (GP RNPs), which is critical for their eventual selective inheritance by germ cells. The precise mechanisms and molecular mediators for both cytoskeletal interactions and GP RNPs segregation are the focus of intense research. Here, we report the molecular identification of a zebrafish maternal-effect mutation motley as Birc5b, a homolog of the mammalian Chromosomal Passenger Complex (CPC) component Survivin. The meiosis and mitosis defects in motley/birc5b mutant embryos are consistent with failed CPC function, and additional defects in astral microtubule remodeling contribute to failures in the initiation of cytokinesis furrow ingression. Unexpectedly, the motley/birc5b mutation also disrupts cortical microfilaments and GP RNP aggregation during early cell divisions. Birc5b localizes to the tips of astral microtubules along with polymerizing cortical F-actin and the GP RNPs. Mutant Birc5b co-localizes with cortical F-actin and GP RNPs, but fails to associate with astral microtubule tips, leading to disorganized microfilaments and GP RNP aggregation defects. Thus, maternal Birc5b localizes to astral microtubule tips and associates with cortical F-actin and GP RNPs, potentially linking the two cytoskeletons to mediate microtubule-microfilament reorganization and GP RNP aggregation during early embryonic cell cycles in zebrafish. In addition to the known mitotic function of CPC components, our analyses reveal a non-canonical role for an evolutionarily conserved CPC protein in microfilament reorganization and germ plasm aggregation.

关键词： Amyotrophic lateral sclerosis   Estradiol   Estrogen receptor   Motoneuron   Spinal cord   Proinflammatory cytokines  

摘要： Amyotrophic lateral sclerosis (ALS) is an adult-onset degenerative disorder characterized by motoneuron death. Clinical and experimental studies in animal models of ALS have found gender differences in the incidence and onset of disease, suggesting that female hormones may play a beneficial role. Cumulative evidence indicates that 17 beta-estradiol (17 beta E2) has a neuroprotective role in the central nervous system. We have previously developed a new culture system by using rat spinal cord embryonic explants in which motoneurons have the singularity of migrating outside the spinal cord, growing as a monolayer in the presence of glial cells. In this study, we have validated this new culture system as a useful model for studying neuroprotection by estrogens on spinal cord motoneurons. We show for the first time that spinal cord motoneurons express classical estrogen receptors and that 17 beta E2 activates, specifically in these cells, the Akt anti-apoptotic signaling pathway and two of their downstream effectors: GSK-3 beta and Bcl-2. To further validate our system, we demonstrated neuroprotective effects of 17 beta E2 on spinal cord motoneurons when exposed to the proinflammatory cytokines TNF-alpha and IFN-gamma. These effects of 17 beta E2 were fully reverted in the presence of the estrogen receptor antagonist ICI 182,780. Our new culture model and the results presented here may provide the basis for further studies on the effects of estrogens, and selective estrogen receptor modulators, on spinal cord motoneurons in the context of ALS or other motoneuron diseases.

关键词： Brassica   Gene expression   Microarray   Microspore-derived embryos   Shoot apical meristem  

摘要： Altered expression of Brassica napus (Bn) SHOOTMERISTEMLESS (STM) affects the morphology and behaviour of microspore-derived embryos (MDEs). While down-regulation of BnSTM repressed the formation of the shoot meristem (SAM) and reduced the number of Brassica MDEs able to regenerate viable plants at germination, over-expression of BnSTM enhanced the structure of the SAM and improved regeneration frequency. Within dissected SAMs, the induction of BnSTM up-regulated the expression of many transcription factors (TFs) some of which directly involved in the formation of the meristem, i.e. CUP-SHAPED COTYLEDON1 and WUSCHEL, and regulatory components of the antioxidant response, hormone signalling, and cell wall synthesis and modification. Opposite expression patterns for some of these genes were observed in the SAMs of MDEs down-regulating BnSTM. Altered expression of BnSTM affected transcription of cell wall and lignin biosynthetic genes. The expression of PHENYLALANINE AMMONIA LYASE2, CINNAMATE 4-4HYDROXYLASE, and CINNAMYL ALCOHOL DEHYDROGENASE were repressed in SAMs over-expressing BnSTM. Since lignin formation is a feature of irreversible cell differentiation, these results suggest that one way in which BnSTM promotes indeterminate cell fate may be by preventing the expression of components of biochemical pathways involved in the accumulation of lignin in the meristematic cells. Overall, these studies provide evidence for a novel function of BnSTM in enhancing the quality of in vitro produced meristems, and propose that this gene can be used as a potential target to improve regeneration of cultured embryos.

关键词： Tibetan chicken   Hypoxia   Embryos   Globin   Hemoglobin  

摘要： Tibetan chicken (Gallus gallus) is a specific chicken breed with strong ability to resist hypoxia, especially during embryonic stage. Though this breed has lived in Tibet plateau for thousands of years, the adaptive mechanism in response to hypoxia is still unknown. In order to obtain a better understanding of the mechanism of hypoxic adaptability in high altitude, we analyzed the mRNA expression pattern of globins in the present study. The fertilized eggs from Tibetan chicken and dwarf recessive white chicken breeds were incubated under normoxic (21% O-2) and hypoxic (13% O-2) conditions, equivalent to the altitude of 3600 m. We observed that Tibetan chicken embryos had higher hatchability (48%) in hypoxia than their lowland controls (7.8%). Northern blot showed that globin mRNA expression in Tibetan chicken embryos differed greatly from lowland controls under hypoxia. The expressions of four dominant globin mRNAs, named alpha(A), alpha(D), beta(A) and beta(H), were significantly induced under hypoxia. Tibetan chicken embryos had lower globin mRNA level in red cells than that of lowland controls at day 19 (P<0.05). Based on real-time PCR the same result was confirmed. Furthermore, we observed accumulation of globins induced by hypoxia in red cells by performing the separation of globin analysis, showing higher level of globins in red cells of Tibetan chicken embryos than that of lowland chicken embryos. Overall, our results provide new evidence that flexible regulation of globins at the level of transcription and translation may play a role in allowing the Tibetan chicken embryo to resist hypoxia. (C) 2012 Published by Elsevier Inc.

关键词： embryo   fetal physiology   in vitro screens   mechanisms of teratogenesis   pharmaceuticals   ion-channel blockers   hERG   heart function   hypoxia  

摘要： BACKGROUND Dofetilide is an antiarrhythmic drug that blocks the cardiac repolarizing current IKr ((IKr, rapid component of the delayed rectifying potassium current). Previous studies have shown that (a) IKr is essential for normal cardiac function of the embryonic heart and (b) dofetilide is teratogenic in rodents. This study was undertaken to examine the mechanism by which dofetilide causes limb defects on gestational day 13 (GD 13) in the rat. METHODS Rats were treated with dofetilide (single oral dose, 5 mg/kg) on GD 13 and embryonic heart rates assessed by ultrasound (Vevo770, VisualSonics, Toronto, Ontario, Canada) 2 hr later. Fetuses were examined for malformations on GD 20. In a separate experiment, dofetilide treatment of GD 13 rats was followed 2, 4, 12, or 24 hr with iv dosing with the hypoxia marker, pimonidazole (60 mg/kg). Embryos were collected and heart rates were assessed in vitro and hypoxia in embryo limbs analyzed. RESULTS A teratogenic dose of dofetilide at a susceptible stage of development (GD 13) resulted in a period of bradycardia and arrhythmia of the embryonic heart and hypoxia in the developing limbs (GD 13) resulting in limb malformations (GD 20). CONCLUSIONS Drugs that induce periods of bradycardia and/or arrhythmia of the embryonic heart and cause the embryo to become hypoxic are potential human teratogens.

关键词： 组织学与胚胎学   实验教学  

摘要： 实验教学是组织学与胚胎学的重要环节，是理论教学的重要补充。为了提高实验课的教学质量，本文对组织学与胚胎学实验教学方法进行探讨。

关键词： 食管癌   酪氨酸激酶受体RON   病理机制   组织芯片  

摘要： 目的:探讨原癌基因RON在正常胚胎食管组织发育成熟及肿瘤组织中的表达特征及临床意义。方法:采用高密度组织芯片和免疫组化染色方法,检测RON在正常胚胎食管组织、成人食管组织和食管肿瘤组织中的表达及分布,半定量方法计算RON表达水平,分析比较差异。通过免疫印迹Western-blot法和RT-PCR法检测食管癌与正常食管组织中RON蛋白和基因的表达水平。结果:RON在正常胚胎食管与成人食管组织中的表达和分布差异无统计学意义(P>0.05)。RON在食道癌组织中呈高表达(P<0.05),其中12.5%食管癌组织中RON呈过度表达,且主要表达在食管癌细胞膜,而正常胚胎食管组织呈极弱或低表达。结论:RON在胚胎食管组织发育和成熟过程中稳定表达;RON的异常表达与食管癌的发生、进展密切相关。

关键词： 组织学与胚胎学   学习团队   管理模式   自主学习  

摘要： 组织学与胚胎学是一门融理论性和实践性为一体的课程。组建自我管理的学生学习团队,将团队管理的理念和模式引入组织学与胚胎学课程教学中,有效提高了学生的学习能力、协作能力和学习效率。

关键词： 组织学与胚胎学   教学模式   网络辅助教学  

摘要： 组织学与胚胎学是基础医学的主干课程,属形态学科,其内容抽象,知识繁杂,授课形式单一,学员学习积极性低。因此,如何创新组织学与胚胎学教学模式,调动学员的学习热情,加深学员对知识的掌握是教学中亟须解决的重要问题。通过网络辅助教学,利用多媒体计算机的文本、图形、动画、视频和音频的综合处理能力及其交互特点,可以将文字和图片有机地结合起来,创造出图文并茂、形象生动的教学环境,提高了教学质量。