Objective To observe the value of MRI quantified uterine indictors in late pregnancy for predicting uterine inertia in delivery.Methods A total of 182 pregnant women were retrospectively collected and were divided into uterine inertia group(inertia group,n=67)and non-uterine inertia group(non-inertia group,n=115)based on delivery or cesarean section records.MRI quantified uterine indicators were compared between groups,and those being statistically different were included to build a multivariate logistic regression model for predicting uterine inertia in delivery.The predictive performance of this model was evaluated using receiver operating characteristic(ROC)curve and the area under the curve(AUC).Results The inertia group had more previous uterine surgeries,also higher proportion of in vitro fertilization and embryo transfer(IVF-ET)and cesarean sections compared to the non-inertia group(all P＜0.05).In late pregnancy,the longitudinal diameter of the uterus,cervical length and the thickness of the myometrium at the placental attachment site in inertia group were larger than those in non-inertia group(all P＜0.05).Increased times of previous uterine surgeries,undergoing IVF-ET,as well as increased longitudinal diameter of the uterus and cervical length in late pregnancy were all independent predictors of uterine inertia in delivery(all P＜0.05).AUC of the multivariate logistic regression model established based on the above factors for predicting uterine inertia in delivery was 0.733.Conclusion MRI quantified uterine indictors in late pregnancy could be used to predict uterine inertia in delivery.

Objective To observe the value of MRI quantified uterine indictors in late pregnancy for predicting uterine inertia in delivery.Methods A total of 182 pregnant women were retrospectively collected and were divided into uterine inertia group(inertia group,n=67)and non-uterine inertia group(non-inertia group,n=115)based on delivery or cesarean section records.MRI quantified uterine indicators were compared between groups,and those being statistically different were included to build a multivariate logistic regression model for predicting uterine inertia in delivery.The predictive performance of this model was evaluated using receiver operating characteristic(ROC)curve and the area under the curve(AUC).Results The inertia group had more previous uterine surgeries,also higher proportion of in vitro fertilization and embryo transfer(IVF-ET)and cesarean sections compared to the non-inertia group(all P＜0.05).In late pregnancy,the longitudinal diameter of the uterus,cervical length and the thickness of the myometrium at the placental attachment site in inertia group were larger than those in non-inertia group(all P＜0.05).Increased times of previous uterine surgeries,undergoing IVF-ET,as well as increased longitudinal diameter of the uterus and cervical length in late pregnancy were all independent predictors of uterine inertia in delivery(all P＜0.05).AUC of the multivariate logistic regression model established based on the above factors for predicting uterine inertia in delivery was 0.733.Conclusion MRI quantified uterine indictors in late pregnancy could be used to predict uterine inertia in delivery.

Objective To observe the value of placental MRI morphological indicators for diagnosing placenta accreta spectrum(PAS).Methods Totally 214 pregnant women who underwent prenatal placental MR examination were retrospectively enrolled and divided into PAS group(n=110)and non PAS group(n=104)based on the presence of PAS or not,also into PAS subgroup and non PAS subgroup during different weeks of pregnancy.Clinical and MRI data were compared between groups and subgroups,and the value of placental MRI morphological indicators for diagnosing PAS was analyzed.Results Significant differences of pregnant women's age,gestational week at MR examination,delivery gestational week,times of pregnancies,deliveries,cesarean sections,miscarriages and uterine clearances,as well as proportion of placenta praevia were found between groups(all P＜0.05).During 28-32 weeks and 32+1-36 weeks of pregnancy,significant differences of placental diameter,area and volume were found between subgroups(all P＜0.05),while no significant differences of placental MRI morphological indicators at gestational age＞36 weeks was found between subgroups(all P＞0.05).The area under the curve(AUC)of placental diameter,area and volume for diagnosing PAS at 28-32 weeks of pregnancy was 0.749,0.729 and 0.791,respectively,at 32+1-36 weeks was 0.718,0.686 and 0.614,respectively,being not significantly different(all P＞0.05).Conclusion Placental MRI morphological indicators at 28-36 weeks of pregnancy were helpful for diagnosing PAS.

Objective To observe the value of placental MRI morphological indicators for diagnosing placenta accreta spectrum(PAS).Methods Totally 214 pregnant women who underwent prenatal placental MR examination were retrospectively enrolled and divided into PAS group(n=110)and non PAS group(n=104)based on the presence of PAS or not,also into PAS subgroup and non PAS subgroup during different weeks of pregnancy.Clinical and MRI data were compared between groups and subgroups,and the value of placental MRI morphological indicators for diagnosing PAS was analyzed.Results Significant differences of pregnant women's age,gestational week at MR examination,delivery gestational week,times of pregnancies,deliveries,cesarean sections,miscarriages and uterine clearances,as well as proportion of placenta praevia were found between groups(all P＜0.05).During 28-32 weeks and 32+1-36 weeks of pregnancy,significant differences of placental diameter,area and volume were found between subgroups(all P＜0.05),while no significant differences of placental MRI morphological indicators at gestational age＞36 weeks was found between subgroups(all P＞0.05).The area under the curve(AUC)of placental diameter,area and volume for diagnosing PAS at 28-32 weeks of pregnancy was 0.749,0.729 and 0.791,respectively,at 32+1-36 weeks was 0.718,0.686 and 0.614,respectively,being not significantly different(all P＞0.05).Conclusion Placental MRI morphological indicators at 28-36 weeks of pregnancy were helpful for diagnosing PAS.

Polyethylene terephthalate (PET) is a synthetic polymer consisting of ester bond-linked terephthalate and ethylene glycol. Tremendous amounts of PET have been produced and majority of them enters terrestrial and marine environment as wastes, posing serious threats to the global ecosystems. In 2016, a PET hydrolase from a PET-assimilating bacterium Ideonalla sakaiensis was reported and termed as IsPETase. This enzyme outperforms other PET-hydrolyzing enzymes in terms of its PET hydrolytic activity at ambient temperature, thus holds a great promise for PET biodegradation. In order to improve IsPETase activity, we conducted structure-based engineering to modify the putative substrate-binding tunnel. Among the several variants to the N233 residue of IsPETase, we discovered that the substitution of N233 with alanine increases its PET hydrolytic activity, which can be further enhanced when combined with a R280A mutation. We also determined the X-ray crystal structure of the IsPETase N233A variant, which shares nearly identical fold to the WT protein, except for an open end of subsite Ⅱ. We hypothesized that the smaller side chain of N233A variant might lead to an extended subsite Ⅱ for PET binding, which subsequently increases the enzymatic activity. Thus, this study provides new clues for further structure-based engineering of PETase.
Burkholderiales/enzymology* ; Hydrolases/genetics* ; Polyethylene Terephthalates/metabolism* ; Protein Engineering

Aim To explore the toxicity and safety of five kinds of known positive drugs, cyclophosphamide, acetyl salicylic acid, tetracycline hydrochloride, dexa-methasone acetate and azacitidine, using zebrafish em-bryos. Methods We selected normally developed 4 hpf zygote, and used water bath infecting method to add the drug to the artificial seawater. Each drug had five concentrating groups, a separate control group and solvent control group. We observed the dead zebrafish embryos after 120 hpf drugs, counted the number of deaths and deformities of zebrafish embryos, and cal-culated mortality abnormal rate, the median lethal con-centration (LC50 ), concentration for 50% of maximal effect (EC50 ), therapeutic index (TI) under 120 hpf condition. We also used the formula TI = LC50 / EC50 to calculate positive drug therapeutic index. Based on measured LC50 we calculated most nonlethal concentra-tion (MNLC) of each drug setting, namely 1 / 10 MN-LC, 1 / 3 MNLC, MNLC,LC10 four concentration, tha-lidomide as a positive control, vitamin C as a negative control, artificial seawater as control, 0. 5% DMSO as solvent control. Put in 28. 5 ℃ environment for 120 hours,embryo development was observed daily for de-velopmental state,mortality,deforming rate and abnor-mal condition. Results The result of five drugs LC50 in descending order: cyclophosphamide > azacitidine> tetracycline hydrochloride > acetylsalicylic acid >dexamethasone acetate. EC50 in descending order: cy-clophosphamide > tetracycline hydrochloride > azaciti-dine > acetylsalicylic acid > dexamethasone acetate. The TI values of cyclophosphamide, acetyl salicylic acid, tetracycline hydrochloride, dexamethasone ace-tate, azacitidine were 1. 92, 1. 11, 1. 05, 1. 44, 2. 99, respectively. Conclusion Zebrafish embryo model can be used in the preliminary evaluation of drugs, and the study of early developmental toxicity and safety.

There is emerging evidence from clinical studies that the existence of liver cancer stem cells(CSCs)or tumor initiating cells is responsible for the high recurrence rates of tumor,generation of metastasis,and resistance to therapeutic regimens after therapy. Here,the characteristics of liver CSCs,clinical manifestation,molecular signaling Wnt/β-catenin,signal transducers and activators of transcription 3,NANOG,annexin A3/c-Jun N-terminal kinase,and chapter four-transmembrane 4 L six family member 5/CD44 in liver CSC self-renewal were briefly reviewed. In addition,potential targets for drug therapy were analyzed,providing some reference for drug discovery that selectively target liver CSC self-renewal signals.