Abstract Progesterone (P4) can participate in the development of female mammalian antral follicles through nuclear receptor (PGR). In this experiment, the differences of P4 synthesis and PGR expression in different developmental stages of sheep antral follicles (large > 5mm, medium 2-5mm, small < 2mm) were detected by enzyme-linked immunosorbent assay, immunohistochemistry, qRT-PCR and Western blotting. Secondly, sheep follicular granulosa cells were cultured in vitro. The effects of different concentrations of FSH and LH on P4 synthesis and PGR expression were studied. The results showed that acute steroid regulatory protein (StAR), cholesterol side chain lyase (P450scc) and 3β Hydroxysteroid dehydrogenase (3β-HSD) and PGR were expressed in antral follicles, and with the development of antral follicles in sheep, StAR, P450scc and the expression of 3β-HSD and PGR increased significantly. In vitro experiments showed that FSH and LH alone or together treatment could regulate P4 secretion and PGR expression in sheep follicular granulosa cells to varying degrees, hint P4 and PGR by FSH and LH, and LH was the main factor. Our results supplement the effects of FSH and LH on the regulation of P4 synthesis during follicular development, which provides new data for further study of steroid synthesis and function in follicular development.

SUMMARY OBJECTIVE: The aim of this study was to explore the influencing factors of preterm twin pregnancy. METHODS: In total, 602 twin-pregnant women delivered from February 2016 to February 2020 were analyzed retrospectively. According to whether the pregnant women were preterm or not, they were divided into preterm group (n=363) and term group (n=239). Baseline information, such as maternal age, address, and education level of the pregnant women, were collected. The clinical information of pregnant women, such as chorionic, preeclampsia, gestational diabetes, premature rupture of membranes, abnormal fetal position, and fetal weight, were analyzed. Logistic regression analysis was used to analyze the risk factors. p-value <0.05 was considered statistically significant. RESULTS: In the preterm group, monochorionic diamniotic comorbidities were significantly higher compared with the control group (p<0.05). Higher risks of preterm group have lower education (p<0.05). Multiple logistic regression analysis demonstrated that education, preeclampsia, and premature rupture of membranes were risk factors for preterm twin pregnancy. CONCLUSIONS: Preterm birth in twin pregnancy is associated with many risk factors, such as education, preeclampsia, and premature rupture of membranes. Pregnancy supervision and prenatal guidance for twin pregnancy should be strengthened. Furthermore, early detection and diagnosis of comorbidities can improve maternal and neonatal outcomes.

Abstract The black soil region of Northeast China is an important grain producing area that faces a serious erosion problem. We used SPOT5 remote sensing imagery from 2008 to establish the gully distribution in a typical black soil region located in the Wuyuer and Nemoer River basin, and Landsat Thematic Mapper imagery to designate landscape patterns. Ninety-three sub-basins were determined based on digital elevation model data using a hydrological analysis module for which landscape pattern metrics and gully density were obtained using FRAGSTATS software and the Geographic Information System (GIS) spatial analysis function, respectively. The results show a gully density of 4,219.2 m2/km2 with 10,149.5 ha of eroded dry land and 25,261.2 ha of destroyed dry land. Correlation analysis between gully density and the landscape percentage of dry land and forest, perimeter-area fractal dimension, contagion index, and Shannon’s diversity index indicate that regulation of the proportion of forest, dry land, and grass, and reasonable optimization of landscape arrangement is very important for soil erosion management and control. Additionally, the findings indicate that landscape differences between each sub-basin are not the principal reason for differences in gully erosion. Further research on gully formation should integrate the effect of natural forces and human activities.