[Objective] To study the correlation between kidney cell DNA degradation and postmortem interval within the span of 6-48 hour after the subject rats′ death.[Methods] To select 18 healthy mature female SD rats and equally divide them into 6 groups.To execute the rats with cervical spine articulation and put the rats under the incubator temperature of 25.1℃ (the average temperature of the 5 previous Decembers in Guangzhou prefecture).Sample kidney tissue from the rat separately 0 hour,6 hours,12 hours,24 hours,36 hours,48 hours,and 60 hours after the rats′ execution to prepare monoplast suspension,which is committed to comet assay.The comet images were captured by fluorescence CCD.Kinetic Comet 4.0 software was used to analyze images.Relevant data were collected by kinetic Comet 4.0 software and were subjected to Kruskal-Wallis test.[Results] Within the postmortem interval of 6-48 h,the number of SD rat kidney cell DNA fragments increased as the postmortem interval lengthens.So did the comet tail length.The Oliver tail moment and tail DNA of comet also showed sign of increase in positive proportion to the postmortem interval (their values corresponding to 60-hour-postmortem-interval were not obtainable.Kruskal-Wallis test indicated:the discrepancies of TL among the 6 groups were all significant (P ＜ 0.01).The difference of TM between 6 h group and 12 h group was not significant (P ＞ 0.05).The difference of TM between 24 h and 36 h was significant (P ＜ 0.05).The difference of TDNA among 6 h,12 h,and 36 h groups were not significant (P ＞ 0.05).The difference of TDNA between 36 h and 48 h was significant (P ＜ 0.05).[Conclusion] Degradation of nuclear DNA of the rat kidney cells increases as the postmortem interval lengthens and comet assay may provide important empirical evidence for determining the postmortem interval.

Objective To study the relationship between the DNA content of chondrocytes in the costal cartilage and postmortem interval in putrefactive rat cadavers.Methods Nuclear DNA wag visualized by modified Feulgen's staining method.DNA content of ehondrocytes in the costal cartilage was semi-quantita tively determined by a computerized image analysis system in rats within 35d postmortem.Results Staining intensity of the nuclei was gradually reduced within from 1d to 28d postmortem.The nuclej could not be detected at 35d.The DNA content of chondrocytes decreased time-dependently within 28 days after death as determined semi-quantitatively,which revealed a linear relationship between DNA content and postmortem interval.Conclusion DNA content of chondrocytes in the costal cartilage reduces time-dependently with the extension of postmortem interval.

Objective:To explore the effectiveness, safety and cost between urinary follicle stimulating hormone (uFSH) and recombinant follicle stimulating hormone (rFSH) in controlled ovarian stimulation (COS) in China.Methods:Data were collected from 16 reproductive centers in China covering oocytes collection time from May 1, 2015 to June 30, 2018. Eligible patients were over 18 years old, adopting COS with uFSH (uFSH group) or rFSH (rFSH group) as start gonadotropins (Gn), and using in vitro fertilization (IVF) and (or) intracytoplasmic sperm injection for fertilisation, excluding frozen embryo recovery cycle. Generalised estimating equation was used to address the violation of independency assumption between cycles due to multiple IVF cycles for one person and clustering nature of cycles carried out within one center. Controlling variables included age, body mass index, anti-Müllerian hormone level, cause of infertility, ovulation protocol, type of fertilisation, number of embryos transferred, number of days of Gn use.Results:Totally 102 061 cycles met eligibility criteria and were included in the analyses. In terms of effectiveness, after controlling relevant unbalanced baseline characteristics, compared with rFSH group, the high oocyte retrieval (>15 oocytes was considered high retrieval) rate of uFSH group significantly decreased in gonadotropin-releasing hormone agonist protocol ( OR=0.642, P<0.01) and in gonadotropin-releasing hormone antagonist protocol ( OR=0.556, P=0.001), but the clinical pregnancy rate per transfer cycle and the live birth rate per transfer cycle significantly increased ( OR=1.179, OR=1.169, both P<0.01) in both agonist and antagonist protocols. For safety, multiple analysis result demonstrated that in the agonist protocol, compared with rFSH group, the incidence of moderate to severe ovarian hyperstimulation syndrome of uFSH group significantly decreased ( OR=0.644, P=0.002). The differences in ectopic pregnancy rate and multiple pregnancy rate between the uFSH and rFSH groups were not significant ( P=0.890, P=0.470) in all patients. In terms of cost, compared with rFSH group, the uFSH group had lower total Gn costs for each patient ( P<0.01). Conclusion:For patients who underwent COS, uFSH has better safety, and economic profiles over rFSH in China.