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关键词： 组织学   胚胎学   教材   绪论   评价  

摘要： It was found that addition of an extract from embryonic neural tissue (ENT), which contained 150 mu g/ml proteins, to the culture medium favored viability of catecholaminergic neurons in cultured explants of the midbrain and medulla of newborn rats and establishment of contacts among these neurons. Addition of the ENT extract increased the dopamine level, measured at the 3rd-4th days of culturing, in the explants of the midbrain and medulla by 1.5 and 3.8 times, respectively. Similar indices for noradrenaline in the above structures were 2.5-2.6 times. The content of cAMP and cGMP in the explants increased 2.3 and 2.8 times, respectively, already 2-3 h after the ENT extract addition.

关键词： Abnormalities, Drug-Induced   Animals   Anoxia/chemically induced   Anoxia/physiopathology   Anti-Arrhythmia Agents/adverse effects   Anticonvulsants/adverse effects   Arrhythmias, Cardiac/chemically induced   Arrhythmias, Cardiac/physiopathology   Carbamazepine/adverse effects   Female   Fetus/drug effects   Fetus/pathology   Fetus/physiology   Heart/embryology   Heart/physiology   Humans   Mice   Mice, Inbred C57BL   Phenobarbital/adverse effects   Phenytoin/adverse effects   Pregnancy   Rats   Trimethadione/adverse effects  

摘要： Antiepileptic drugs (AEDs), such as phenytoin (PHT), carbamazepine (CBZ), trimethadione (TMD), and phenobarbital (PB), have all been associated with a similar pattern of malformations, as well as growth retardation and developmental delay. Valproic acid (VPA) has been associated with a different pattern of malformations. Recent studies suggest that PHT's fetal adverse effect is related to its membrane stabilizing pharmacological properties (blockage of voltage-dependent ion channels). During a restricted sensitive period, this results in induction of concentration-dependent bradyarrhythmia in the embryo and episodes of hypoxia/reoxygenation. The aim of this study was to compare the potential of PHT, CBZ, PB, TMD, and dimethadione (DMD;the active metabolite of TMD) to cause bradyarrhythmias. All of these AEDs exert mainly their pharmacological effect via blockage of ion channels. VPA and vigabatrin (VGB), which are pharmacologically active mainly by other mechanisms, were also tested. C57 BI/6J mouse embryos were cultured in vitro on gestation day 10 in vitro (in 20% rat serum). The drugs were suspended in either water or dimethylsulfoxide and administered into the culture medium in increasing concentrations up to 20 times the human therapeutic plasma concentration. A scoring system was employed in order to rank the drugs based on their potential to cause bradycardia, ventricular arrhythmia, and cardiac arrest in relation to human therapeutic concentrations. Based on this system, the drugs were ranked as follows: DMD = PHT much greater than PB = CBZ > TMD = VPA much greater than VGB (no potential). The results correlate well with the available clinical/experimental data of the tested AED's potential to induce hypoxia-related fetal adverse effects, such as oral clefts, distal limb defects, growth retardation, and developmental delay. The results support the idea that adverse fetal effects after in utero exposure to PHT, PB, CBZ, and TMD (via the active metabolite DMD)

关键词： 医学专科生   组织胚胎学   教学模式  

关键词： 青扦   胚性愈伤组织   悬浮培养   体细胞   胚胎发生  

摘要： 在含１ｍｇ／Ｌ２，４－Ｄ、１ｍｇ／ＬＫＴ、３０ｇ／Ｌ蔗糖的５９液体培养基上建立了生长旺盛的青扦胚性愈伤组织悬浮系，并对胚性愈伤组织悬浮系生长、体细胞胚胎发生、底物消耗、ｐＨ值、电导率的动力学过程及各参数的相关性进行了研究。经悬浮培养的胚性愈伤组织转入含３ｍｇ／ＬＡＢＡ、８００ｍｇ／ＬＧｌｕ、５００ｍｇ／ＬＣＨ、３０ｇ／Ｌ蔗糖的１／２改良５９固体培养基进行分化，可产生大量的体细胞胚，并逐渐长成形态正常的多子叶小苗。

关键词： 胚胎脊髓组织移植   成年   宿主   脊髓功能   脊髓损伤  

摘要： 目的探讨胚胎脊髓组织移植促进成年宿主损伤脊髓功能恢复的作用。方法采用成年大鼠脊髓半切洞损伤模型,移植胚胎大鼠脊髓组织,术后进行联合行为计分(CBS)、体感诱发电位(SEP)、运动诱发电位(MEP)和性行为及生育机能检查。结果移植组CBS与对照组比较相差显著(P<0.05),移植术后4周以内两者相差非常显著(P<0.0l);移植组SEP、MEP早期反应的峰潜伏时恢复优于对照组(P<0.05);术后4～12周75%的雌鼠阴道涂片检出精子并能正常生育。结论胚胎脊髓移植能促进成年宿主损伤脊髓的功能恢复。

关键词： 扬子鳄   喉   组织发生  

摘要： 观察了２０例扬子鳄胚胎的喉发生过程。孵育第６天出现喉气管憩室，第８天出现喉原基。孵育１０～２０天，原始喉腔上皮细胞分裂增殖加快，喉腔侧壁中部的上皮向两侧中胚层不断突出，喉腔渐扩大。第３０～４８天，喉腔的背室及左右腹室逐渐明显。喉肌及喉软骨于第３４天开始分化，第４８天，喉肌发育成横纹肌，喉软骨化基本完善。固有膜及粘膜下层于第４０天开始出现，第４８～６２天，其中的血管分布渐增多。孵育第４０天，喉上皮表层出现一层死亡细胞，第４８～６２天，喉上皮层为复云上皮，由两层细胞组成上皮中的基细胞、纤毛细胞及杯状细胞渐发育成熟。讨论了扬子鳄喉腔的形成及喉上皮细胞分化的某些特点。

ISBN: (纸本)781034806X

关键词： ascidian embryo   centrosome-attracting body   nuclear shift   posterior cytoplasm   unequal cleavage  

摘要： The mechanism of unequal cleavage is one of the most intriguing subjects in cell biology. Previous studies of unequal cleavage have focused on a limited number of organisms such as yeasts, nematodes, sea urchins and annelids. The cleavage pattern of the ascidian embryo is invariant. In the ascidian embryo, the posterior-most blastomeres divide unequally in three successive cleavages. In the present study, it was shown that the ascidian embryo provides another good experimental system with which to analyze the mechanism of unequal cleavage. A novel structure, designated as CAB (centrosome-attracting body), which was found specifically in the unequally cleaving blastomeres was described. In the course of unequal cleavages, first, a thick microtubule bundle appeared between CAB and one of the centrosomes. Then with the shortening of the microtubule bundle, the nucleus with the centrosome was drawn toward CAB, situated at the posterior cortex of the blastomere. Finally, a cleavage furrow formed in the middle of the asymmetrically located mitotic apparatus and produced two blastomeres of different size, generating a smaller cell that inherits CAB. The CAB seemed to play an essential role in the unequal cleavages in the ascidian embryo.

关键词： dentate gyrus   granule cell   mossy cell   synapse formation   glutamate   GABA   organotypic culture  

摘要： Cultured explants obtained from the dentate gyrus of rat embryos (embryonic day 19-20) were used to investigate synapse formation and morphological differentiation of neuron types in the absence of extrinsic afferents. Synaptogenesis was studied by whole-cell recordings of postsynaptic currents and by ultrastructural analysis. Neurons were visualized using Lucifer Yellow filling or staining with DiI. In short-term (3-5 days) cultured explants postsynaptic currents were rarely evoked by extracellular stimulation and synapses were almost completely absent at the ultrastructural level. After 6-10 days in vitro, the incidence of evoking postsynaptic currents mediated by glutamate and GABA(A) receptors was strongly increased. At the ultrastructural level, the density of synapses increased more than 20-fold. These results demonstrate de novo formation of synapses in cultured embryonic dentate gyrus explants. Neuron types could be discriminated by their dendritic arborizations and by their electrophysiological properties. After 6-10 days in vitro, messy-like cells exhibited 3-4 primary dendrites branching in a characteristic pattern and showed moderate spike-frequency adaptation. Application of serotonin (5-HT) to cultured explants elicited GABA(A)-receptor-mediated postsynaptic currents in messy-like cells, indicating synaptic GABA release from local interneurons. Comparison to 5-HT evoked GABA release in mossy cells in age-matched, acute slices revealed only slight quantitative differences. In contrast to mossy cells, granule cells showing several primary dendrites originating at one cell pole were almost completely absent in cultured explants, suggesting an involvement of extrinsic afferents in the differentiation of granule cells. (C) 1998 Elsevier Science B.V.