The endocrine control of embryonic lung maturation in the chicken. I. Morphological and biochemical differentiation of lungs after "in ovo" decapitation

Summary The effects of in ovo hypophysectomy on lung maturation of the chick embryo were investigated. Both biochemical and morphological aspects of differentiation were markedly delayed in experimental embryos: the phospholipid content of lungs was lower than in controls at all stages, whereas the water content remained very high. The type II pneumocytes, which normally appear within the epithelium on day 16 of incubation, started to differentiate only between days 18 and 20 of incubation in the decapitated embryos. The differentiation of type I pneumocytes leading to the formation of air capillaries was also slowed down: they did not appear until the end of incubation in decapitated embryos, whereas they normally start to appear on day 19. The presence of an intact hypophysis is thus essential for normal lung maturation in the chicken.     

非悬滴开放式培养法在鸡胚背根节体外培养中的应用

本研究针对悬滴培养法在操作和应用上存在的问题和局限性，改用操作简便、适用范围广的非悬滴开放式培养法培养鸡胚背根节。将数个鸡胚背根节按一定间隔种植在内置生长基质盖玻片的35mm培养皿中，加人适量培养液，置于CO2。孵箱中进行培养。结果显示.从培养24h至60h各时期，培养皿中背根节生长状况均良好，神经突起明显增长，表明用非悬滴开放式培养法培养鸡胚背根节是可行且可靠的。     

The efficacy and efficiency of an in-vitro fertilization programme including embryo cryopreservation: a cohort study

A cohort of 485 couples starting their first in-vitro fertilization(IVF) attempt between January, 1989 and February, 1991 inclusive,were followed until June 1, 1992. A total of 1086 treatmentcycles were initiated (mean 2.2, range 1–6). Of these,235 (21.8%) cycles were cancelled, giving a total of 851 embryoreplacements (mean 1.7, range 1–5). After IVF treatment,189 women have either delivered or have an ongoing pregnancyin the second or third trimester. This gives a baby take-homerate of 17.4% per started cycle and 22.2% per embryo replacement.For 91 (18.6%) of the couples, the treatment was abandoned priorto completion of the three scheduled IVF attempts and 57 (11.7%)of these had no completed IVF cycles. In the group of coupleswith reduced sperm quality, the delivery rate was significantlylower than that of the other groups. A total of 193 women hadembryos cryopreserved in at least one IVF cycle; 124 of thesewomen started a frozen embryo replacement cycle and 88 had atleast one cycle with replacement of frozen/thawed embryos, resultingin 25 deliveries/ongoing pregnancies. Due to the Norwegian lawon assisted procreation 65 (33.7%) of the women have had theirfrozen embryos thawed and discarded after 12 months of storage.The cryopreservation programme, with the limitations of theNorwegian law, gives a 5.2% increase in the baby take-home ratefor women entering the IVF programme, an increase of 13.2% inthe number of ongoing pregnancies/deliveries and an 11.6% increasein number of children/viable fetuses. A total of 214 women havedelivered or have ongoing pregnancies in the second or thirdtrimester. This represents 44.1% of the 485 women accepted forIVF treatment, irrespective of whether they were treated ornot, and 50.0% of those couples who completed at least one IVFcycle.     

扬子鳄胚胎中肾发生及退化

目的：在11个不同发育时期扬子鳄胚胎中观察中肾的发生及退化过程。方法：采用电镜、细胞化学及免疫组织化学方法。结果：孵育第6期在中肾管前端附近出现一些中肾小泡。第8期形成“S”形中肾小管。第13—17期鳄胚体前部部分中肾小管盲端内陷，形成原始的肾小囊和肾血管球，中肾小管显著伸长并迂回曲折。第20一22期，体前后部中肾组织均已形成完整的肾单位。中肾小管颈段由纤毛柱状上皮细胞组成，近球小管上皮细胞含丰富的PAS阳性物质并呈表皮生长因子(EGF)、转化生长因子(TGFβ1)和生长抑素(SS)免疫阳性反应。第24—28期，体前部至后部的中肾组织依次退化。结论：(1)扬子鳄中肾除重吸收作用外还具有内分泌功能；(2)中肾退化时，细胞凋亡依次表现为核固缩，出现大量凋亡小体，线粒体数目剧增并膨胀，线粒体等细胞器自溶及核消失；(3)中肾退化可能与小管细胞中TGFβ1及SS大量表达有关。     

Paternal effects acting during the first cell cycle of human preimplantation development after ICSI.

BACKGROUND: The ability of human embryos to undergo normal development has been shown previously to be subject to strong paternal (sperm-derived) effects. This study was undertaken to determine whether paternal influences on human embryo quality are detectable as early as the first cell cycle after fertilization. METHODS: The quality of zygotes and cleaving embryos resulting from sibling donor oocytes fertilized by sperm from different patients were compared in a donor oocyte-sharing programme. RESULTS: Fertilizations with sperm from certain individuals repeatedly resulted in the formation of high proportions of zygotes with abnormal pronuclear morphology that subsequently tended to cleave slowly and to show extensive fragmentation and blastomere irregularities. This phenomenon was observed with oocytes from two different donors for each of these individuals and contrasted with normal developmental performance of embryos resulting from sibling oocytes fertilized by sperm from other men with similar basic sperm characteristics. Fertilization rates were not related to these differences. CONCLUSIONS: These data point to a very early onset of paternal effects that condition human embryo development. These effects may be both of genetic (related to the minor gene activity of the male pronucleus) or epigenetic (related to the sperm-derived oocyte-activating factor or sperm centrosome) origin.     

Serum relaxin and the major endometrial secretory proteins in in-vitro fertilization and down-regulated hormone-supported and natural cycle frozen embryo transfer

Relaxin has been postulated to be a modulator of the expressionof the endometrial secretory proteins, insulin-like growth factorbinding protein (IGFBP-1) and placental protein 14(PP14). Thisstudy evaluated the expression of relaxin in relation to concentrationsof these secretory proteins along with oestradiol, progesteroneand human chorionic gonadotrophin in groups of pregnant andnon-pregnant patients who underwent differing assisted conceptiontreatments. Serum samples were taken from 88 patients at 8 and12 days after embryo transfer. At 12 days after embryo transfer,relaxin concentrations in the pregnant patients who had undergonein-vitro fertilization (IVF) or natural cycle frozen embryotransfer were significantly higher than those who did not conceivein these groups (mean concentrations 8334 versus 28 and 2608versus 62 pg/ml respectively, P <0.001). However concentrationsin the pregnant patients who had hormone support and transferof frozen embryos were not significantly different from thepatients who did not conceive after the same treatment. Althoughrelaxin expression was associated with corpus luteum activity,it was not related to the number of corpora lutea in IVF patients.A wide range of relaxin concentrations was seen to be compatiblewith a healthy pregnancy. These serum relaxin concentrationswere not found to be directly related to the serum concentrationsof IGFBP-1, PP14 or the other factors assessed in this study.     

磷脂酶C-γ1在人胚胎脊髓中的表达变化

为了了解磷脂酶C-γ1(PLC-γ1)的发育表达变化特点,本研究采用免疫组织化学方法检测不同发育时期的人胚胎脊髓中PLC-γ1的表达及变化。结果显示:PLC-γ1在人胚胎脊髓3周到7个月的整个发育过程中均有表达,在发育早期阳性反应可见于神经管内、外界膜,随着套层、边缘层的形成,神经上皮层、套层中均可见到PLC-γ1阳性反应物,且翼板阳性细胞较基板密集;套层阳性细胞在8、9周时达到高峰,随后开始逐渐减少。3个月时边缘层出现散在的阳性细胞,并随着脊髓的发育而逐渐增多。以上结果提示,PLC-γ1及其与PLC-γ1相关的细胞信号通路对人胚胎脊髓的发育可能发挥了重要的生物学作用。     

Fertilization in vitro increases non-disjunction during early cleavage divisions in a mouse model system

BACKGROUND: We have been studying an unusual mouse-the BALB/cWt (Wt) male-in which the Y chromosome is susceptible to high rates of mitotic non-disjunction, particularly at the first two cleavage divisions. As these are the same divisions that human embryos generated through assisted reproductive technology must complete in an artificial setting, analysis of the Wt Y chromosome allows us to examine the effect of fertilization and culture in vitro on mammalian chromosome segregation. METHODS: We performed standard mouse IVF, cultured embryos in 5% CO2 in air or in a lowered oxygen atmosphere, and used fluorescence in-situ hybridization to examine the sex chromosome constitutions of 2-, 4-, 8- and 16-cell stage Wt Y-bearing embryos. RESULTS: We observed a significant increase in mosaic sex chromosome aneuploidy at each embryonic stage in embryos cultured in 5% CO2 in air, but under lowered oxygen conditions mosaicism returned to control (in-vivo) levels. CONCLUSIONS: Our results demonstrate that slight alterations in in-vitro conditions may have a considerable impact on the genetic quality of assisted reproductive technology-derived embryos and suggest that the genetic quality of embryos should be a fundamental concern in the development of new culture systems for clinical use.