Ultrastructure of bovine placenta during all gestational period / Ultraestrutura de placenta bovina durante todo o período gestacional

Placentas from pregnant cows with different gestation periods were used. Placental fragments of all groups were processed and evaluated by transmission electron microscopy. After fragment analysis, bovine placenta was observed to be epitheliochorial type in early pregnancy, becoming progressively sinepiteliocorial at the beginning of the second trimester. There are no ultrastructural evidences of inflammation in the region of caruncles throughout gestation, despite the invasion of caruncle proper lamina by trophoblast cells. However, throughout pregnancy and especially at the end, there were evident signs of cell degeneration in both trophoblast and the uterine epithelium. The active trophoblast cells intensely phagocytize cellular debris. There are complex interdigitations between the surface of the trophoblast and the uterine epithelium, which is related to the increase of the exchange surface between mother and fetus. At the end of pregnancy, interdigitations disappear, favoring the detachment and expulsion of the placenta after birth.(AU)

Foram utilizadas placentas de vacas abatidas em frigorífico com diversos tempos gestacionais. Fragmentos de placentomo de todos os grupos foram processados e avaliados em microscopia eletrônica de transmissão. Após análise dos fragmentos, observou-se que a placenta bovina é do tipo epiteliocorial no início da gestação, tornando-se sinepiteliocorial progressivamente a partir do início do segundo mês de gestação. Não existem evidências ultraestruturais de inflamação na região das carúnculas durante toda a gestação, apesar da invasão da lâmina própria caruncular por células trofoblásticas. No entanto, durante toda a gestação e em especial ao seu final, foram observados sinais evidentes de degeneração celular, tanto do trofoblasto como do epitélio uterino. As células trofoblásticas ativas fagocitam intensamente os debris celulares originados dessas degenerações. Existem complexas interdigitações entre a superfície do trofoblasto e do epitélio uterino, o que estaria relacionado com o aumento da superfície de troca entre mãe e feto. Ao final da gestação, praticamente desaparecem essas interdigitações, favorecendo o descolamento e a expulsão da placenta após o parto.(AU)

Application of log-linear model in the case-parent triad study / 中华流行病学杂志

We were introducing a log-linear model for case-parent triad study.Data from a previous study of the association between MTHFR C677T aud cleft lip with or without cleft palate (CL/P) was analyzed,in order to investigate the maternal effect,fetal effect and their interaction,using a series of log-linear models.Our results showed that mothers who were carrying two copies of MTHFR C677T variant alleles appeared to have reduced the risk of CL/P in offspring,comparing to those with homozygous of wild-type allele.With S2=0.43 (95％ CI:0.19-0.95).No significant association was found for fetal genotype and maternal-fetal iuteraction with CL/P.Log-linear model method seemed to be useful in the estimation of maternal effect,fetal effect and maternal-fetal interaction,in the case-parent triad study design.This approach showed specific benefit in studies that related to genetic effects on complex diseases such as pregnancy complications and diseases originated from fetus.