全胚胎体外培养方法筛查致畸原的应用

全胚胎体外培养技术是将孕第９．５天的大鼠胚胎从子宫移至体外培养，培养期间在培养基中加入不同的化合物，由于排除了母体和胎盘因素，可以观察到这些化合物对胚胎生长发育的直接影响。应用该技术研究了青霉素、敌枯双、放线菌素Ｄ和高浓度葡萄糖四种化合物对胚胎生长发育的直接影响，结果发现在体外培养时也可导致胚胎死亡、畸形和胚胎生长发育迟缓，所导致的畸形与在整体动物实验结果相同。同时发现化合物在导致胚胎死亡、畸形和生长发育迟缓方面具有明显的剂量－效应关系。通过比较这种化合物导致胚胎死亡、畸形和发育迟缓的剂量－效应曲线的关系，推测其导致胚胎畸形的可能性以及畸形胚胎存活的可能性，从而推测化合物在实际中真正致畸的可能性。     

Gap junction proteins exhibit early and specific expression during intramembranous bone formation in the developing chick mandible

The spatial and temporal expression of three closely related members of the connexin family of gap junction proteins (connexin42, Cx42; connexin43, Cx43; and connexin45, Cx45) was evaluated during bone formation in the mandibular process of the chick embryo. Mandibles of chick embryos from Hamburger and Hamilton stage 25 (approximately 5 days) through 19 days of development were dissected, serially sectioned and processed for immunocytochemical localization, employing site-specific anti-connexin antibodies. Our data revealed that (1) Cx43 was present throughout mandibular bone formation; (2) although it appeared to be associated with all bone cell types, Cx43 was concentrated in mesenchymal cells during the earliest stages in the osteogenic lineage; (3) most importantly, the localization of Cx43 at sites of bone formation appeared to precede the overt expression of the osteogenic phenotype; (4) by contrast, Cx45 was more restricted, spatially and temporally, in its distribution; (5) Cx42 expression was not detected in osteogenic tissue during mandibular bone formation. From all of the data obtained, Cx45 appeared to be associated with stages of bone formation characterized by the elaboration of matrix and the progressive expression of the differentiated osteogenic phenotype. Cx43 appeared to be associated with condensation of mesenchyme and the earliest stages of osteogenesis. Because of these associations, we propose that connexin expression may be necessary for the initiation of bone formation and the full expression of the osteogenic phenotype.     

Ventrally emigrating neural tube cells migrate into the developing vestibulocochlear nerve and otic vesicle

Virtually all cell types in the inner ear develop from the cells of the otic vesicle. The otic vesicle is formed by the invagination of non-neural ectodermal cells known as the otic placode. We investigated whether a recently described cell population, originating from the ventral part of the hindbrain neural tube known as the ventrally emigrating neural tube (VENT) cells, also contributes cells to the otic vesicle. The ventral hindbrain neural tube cells were labeled with the fluorescent vital dye DiI or replication-deficient retroviruses containing the LacZ gene in chick embryos on embryonic day 2, after the emigration of neural crest from this region. One day later, the labeled cells were detected only in the hindbrain neural tube. Shortly thereafter, the labeled cells began to appear in the eighth (vestibulocochlear) cranial nerve and otic vesicle. From embryonic day 3.5-5, the labeled cells were detected in the major derivatives of the otic vesicle, i.e. the endolymphatic duct, semicircular canals, utricle, saccule, cochlea, and vestibulocochlear ganglion. That the emigrated cells originated from the ventral part of the hindbrain neural tube was confirmed by focal application of DiI impregnated filter paper and with quail chimeras. It is concluded that, in addition to the otic placode cells, the otic vesicle also contains the ventrally emigrating neural tube cells, and that both cell populations contribute to the structures and cell types in the inner ear. It is well known that inductive signals from the hindbrain are required for the morphogenesis of the inner ear. The migration of the hindbrain neural tube cells into the otic vesicle raises the possibility that the inductive effect of the hindbrain might be mediated, at least in part, by the ventrally emigrating neural tube cells and that, therefore, a mechanism exists that involves cells rather than diffusible molecules only.     

Effects of opiates on the growth of neuron-enriched cultures from chick embryonic brain

Neuron-enriched cultures derived from 6-day-old chick embryo cerebral hemispheres were treated with morphine or methadone, 10(-5) M or 10(-6) M, on days 4-6 or 6-8 in culture and were evaluated morphologically and biochemically at day 9 using phase contrast microscopy and choline acetyltransferase activity (ChAT) as a cholinergic marker. The treatment of the cultures with morphine markedly affected their growth pattern; specifically, we observed an increased number of flat cells presumptively glia, and aggregates sided by flat cells and devoid of thick bundles of neuritic processes that normally characterize neuron-enriched cultures. These morphologic changes were reflected in a drastic decrease of ChAT activity in cultures treated from day 4 to day 6 but not from 6 to 8. In contrast to morphine, exposure to 10(-6) M methadone from day 4 to day 6 resulted in reduced ChAT activity but the growth pattern of the cultures remained morphologically intact. We suggest that morphine exerts a general neurotoxic effect whereas methadone may affect some specific cholinergic function.     

人胚呼吸道上皮细胞非时序DNA合成

为研究和比较化学致癌物对人呼吸道上皮细胞和纤维母细胞的损伤及损伤后DNA修复合成的差异,作者用直接致癌物4-硝基喹啉-1-氧化物(4-NQO)和间接致癌物3,4-苯并芘(BaP)处理人胚鼻咽、气管上皮细胞和纤维母细胞,用放射自显影术测定这3种细胞的非时序脱氧核糖核酸合成(UDS)。用4-NQO处理后,这3种细胞的UDS均呈明显的剂量依赖(dose dePendency)关系,但气管和鼻咽上皮细胞UDS平均分别是纤维母细胞的3.0和2.4倍。用BaP处理后,气管和鼻咽上皮细胞UDS呈现明显的剂量依赖关系,而纤维母细胞未见这种关系。气管和鼻咽上皮细胞的UDS平均分别是纤维母细胞的8.6和3.0倍。     

麦胚提取物对辐射损伤修复的实验研究

目的 研究麦胚提取物对小鼠辐射损伤修复的调节和保护作用。方法 采用辐射前或辐射同时饲喂一定量的麦胚提取物，观察小鼠经X射线一次性全身照射后的临床症状、30d存活率、骨髓微核率、外周血白细胞总数在不同时间的变化。结果 与对照组(单纯照射)比较，饲喂麦胚提取物可使小鼠的头面部皮肤、小肠黏膜、肾脏损伤症状得到明显改善；30d存活率为86．17％(P＜0．01)，提高存活率41．79％，保护系数为1．72；骨髓微核率4．62‰；比对照组(12．14‰)降低(P＜0．01)；外周血白细胞总数在7，13，20，30d均显回升(P＜0.05，P＜0．01，P＜0．01，P＜0．01)。结论 麦胚提取物对小鼠辐射损伤修复有一定程度的调节和保护作用，对于辅助肿瘤放射治疗具有重要意义。     

Development and Intrauterine Fate of Normal and Abnormal Human Conceptuses

Using the data from the Kyoto Collection of Human Embryos, three main topics related to normal and abnormal development of human embryos are discussed. 1) Wide variability was noted in developmental stage of human embryos at any given gestational age. This was true not only for the estimated ovulation age but also for ‘coital’ age in single coital cases. Such diversity in human prenatal development may be, at least in part, ‘normal’ biological variability and it should be taken into account when assessing the teratogenic risk of environmental agents to human embryos. 2) At the early postimplantation period prior to major organogenesis, the percentage of morphologically abnormal embryos is high (> 30%), which supports the clinical finding that a substantially large proportion of human conceptuses are eliminated at an early stage of pregnancy, often without the knowledge of the mother. The fate of undifferentiated abnormal embryos is not certain and should be studied. 3) Life-table estimates for normal and abnormal human conceptuses showed that more than 10% of all embryos recognizable at 5 weeks gestation are malformed or ‘potentially’ malformed. Because of selective intrauterine death of malformed embryos and fetuses, the proportion of the malformed drops to 2.4% by age 8 weeks and 1% at term. The cumulative intrauterine mortality rate of malformed conceptuses was estimated to be 93%, while the corresponding rate for normal conceptuses was 18%.     

人胚胎胃肠及胰腺D细胞发生的研究

用免疫细胞化学方法研究人胚胎各时期胃肠胰的Ｄ细胞发生及其形态与功能的关系。结果发现：Ｄ细胞最早出现于６周零５天胚的十二指肠，７周零３天胚的胰、胃、空肠，７周零６天胚的回肠，８周零４天胎的结肠及１０周零５天胎的阑尾；细胞密度在胚期低，胎期逐增，至胎晚期又依次在胰、胃窦、十二指肠、胃体、空肠、回肠、升结肠及阑尾中降低，且肠绒毛顶端可见衰老的Ｄ细胞。提示胚胎Ｄ细胞的发生与胃肠胰的发育有关。     

Clinical outcomes of two different endometrial preparation methods for cryopreserved-thawed embryo transfer in patients with a normal menstrual cycle

Aim:  To compare the clinical outcomes of cryopreserved-thawed embryo transfer among patients with a normal menstrual cycle who had natural or hormone-replacement cycles.
Methods:  From January 2004 to June 2006, cryopreserved embryos following conventional in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) were thawed and transferred in a total of 720 natural cycles and 136 hormone-replacement cycles.
Results:  Cryopreserved-thawed embryo transfer in patients who had a natural or hormone-replacement cycle resulted in clinical pregnancy in 43.1% and 40.4%, respectively; a rate of miscarriage of 14.5% and 23.6%, respectively; and a rate of ongoing pregnancy and delivery of 36.5% and 30.9%, respectively. None of these differences were statistically significant.
Conclusions:   Patients with a normal menstrual cycle who have natural or hormone-replacement cycles can be expected to have comparable clinical outcomes with cryopreserved-thawed embryo transfer. (Reprod Med Biol 2007; 6 : 53–57)     

二硫化碳对大鼠胚胎发育及血清锌和铜含量影响的研究

本文观察了CS_2对大鼠胚胎发育及血清锌、铜含量的影响。发现胚胎着床前死亡率升高,胎鼠皮下出血、心包淤血及骨骼骨化不金的发生率增高。但无明显的致畸效应。14.1及103.9ng/m~3的CS_2对妊娠大鼠的血清锌、铜含量无明显影响。说明CS_2对大鼠的胚胎毒性与其对妊娠大鼠血清锌、铜含量的影响之间没有关联。