Objective:To investigate the risk factors for severe postpartum hemorrhage (SPPH) during vaginal delivery of twin pregnancy.Methods:A retrospective analysis was conducted on clinical data from twin pregnancies ≥28 weeks′ gestation undergoing vaginal delivery at Peking University Third Hospital between January 2016 and December 2023. The twin pregnant women were divided into the SPPH group (postpartum hemorrhage ≥1 000 ml within 24 hours) with 22 cases and the non-SPPH group with 171 cases. The differences between the two groups were compared and the risk factors for SPPH were analyzed.Results:(1) The incidence of SPPH during vaginal delivery in twin pregnancies was 11.4% (22/193). The causes of SPPH included 12 cases (54.5%, 12/22) of simple uterine atony, 4 cases (18.2%, 4/22) of uterine atony combined with vaginal lacerations after forceps delivery, and 6 cases (27.3%, 6/22) of uterine atony combined with placental factors. (2) The age and postpartum hospital stay in the SPPH group were significantly higher than those in the non-SPPH group (all P<0.05). Compared to the non-SPPH group, the proportion of hypertensive disorders in pregnancy, accreta placenta implantation, and anemia in the SPPH group were significantly increased, and the birth weight of newborn 1st, the sum of the birth weights of two newborns, the duration of the second stage of labor, and the proportion of labor followed induction were also significantly increased (all P<0.05). (3) Multivariate analysis showed that age ≥38 years ( OR=16.785, 95% CI: 2.679-105.166; P=0.003), the second stage of labor ≥90 minutes ( OR=9.670, 95% CI: 2.532-36.930; P=0.001), hypertensive disorders in pregnancy ( OR=5.945, 95% CI: 1.702-20.761; P=0.005), and anemia ( OR=8.048, 95% CI: 2.086-31.049; P=0.002) were independent risk factors for SPPH in twin pregnancies during vaginal delivery. Conclusions:Anemia should be actively corrected during twin pregnancy. For twin pregnant women with advanced age, hypertensive disorders in pregnancy, or other risk factors of SPPH, if vaginal delivery is chosen, attention should be paid to the management of labor duration, dynamic assessment of the risk of postpartum hemorrhage, and proactive measures should be taken to ensure a smooth vaginal delivery and effectively reduce the incidence of SPPH.

Space radiation is the most important environmental harmful factor in long-term manned spaceflight and deep space exploration, and it may produce deterministic and stochastic effects on tissues and organs. In-depth research into the biological effects, mechanisms, and protective measures of space radiation is essential and serves as an important foundation for exploring radiation biology and promoting major manned space projects. Firstly, this review introduces the spatiotemporal distribution characteristics of space radiation during low-earth orbit flights, manned lunar landings, and deep space exploration missions, as well as the health risks and challenges it posed to astronauts. Then, it discusses medical requirements and exposure limits, risk assessment, and protection technologies included in the space radiation protection system established internationally and over 30 years of Chinese manned spaceflight departments. Finally, it outlines the subsequent work and prospects for further research.

Objective:To compare the pregnancy outcomes of surviving fetuses in monochorionic diam-niotic(MCDA)twin pregnancies after selective feticide or spontaneous single intrauterine fetal demise(sIUFD),and to explore the influencing factors of prognosis.Methods:A total of 219 cases of intra-uterine death of one fetus in MCDA twin pregnancies admitted to Peking University Third Hospital from September 2010 to August 2021 were collected.According to the mode of fetal death,they were divided into the spontaneous sIUFD group(120 cases)and the selective feticide group(99 cases).Data on the maternal conditions during pregnancy,the situation of the intrauterine-dead fetus,and pregnancy out-comes were collected for retrospective case-analysis.Results:The live-birth rates of surviving fetuses in the spontaneous sIUFD group and the selective feticide group were 85.0％and 81.8％respectively,and the total perinatal survival rates of surviving fetuses were 73.3％and 81.8％respectively,and there were no statistically significant differences.Compared with the spontaneous sIUFD group,the selective feticide group had a greater gestational week at delivery,and lower rate of preterm birth before 37 weeks,neonatal asphyxia,and early neonatal mortality.Using the gestational week at delivery as the outcome variable,Cox regression analysis showed that the mode of fetal death was not a risk factor affecting the gestational week at delivery of the surviving fetus,while gestational hypertension and the gestational week of fetal death were independent risk factors affecting the gestational week at delivery of the surviving fetus.Using preterm birth before 37 weeks,intrauterine death of the surviving fetus,and abnormal neonatal cranial ultrasound as outcome variables respectively,unconditional logistic regression analysis showed that the mode of fetal death,the gestational week of fetal death,the position of the dead fetus,and fetal complications were independent risk factors affecting the outcomes of the above-mentioned survi-ving fetuses.According to the results of the univariate analysis,the above risk factors were included in the multivariate regression analysis,and the results were the same as those of the univariate analysis.Conclusion:For MCDA twin pregnancy patients with severe twin-related complications,the prognosis of surviving fetuses after selective feticide is better.The proactive intrauterine intervention and treatment are of great significance for improving the prognosis of surviving fetuses.

Objective To investigate the effect of triptolide(TPL)on renal interstitial fibrosis in mice with unilateral ureteral obstruction(UUO)and its mechanism.Methods Six male C57BL/6J mice were randomly selected as the sham group,and 12 mice with UUO modeling were randomly divided into the model group(UUO)and the triptolide group(TPL).Changes in serum creatinine(SCr),blood urea nitrogen(BUN),and body weight were compared among the groups.Renal tissue specimens were collected at 14 d after UUO for HE and Masson staining.Immunohistochemistry staining was performed to observe the expression of α-smooth muscle actin(α-SMA)and fibronectin(Fn)in kidney tissues.Western blotting analysis was used to detect the protein expression levels of nucleotide combined with structure of oligomerization domain receptor protein 3(NLRP3),GSDMD,cGSDMD,IL-1β and IL-18.Results At week 1,the body weight of mice in the UUO and TPL groups significantly decreased compared with that in the sham group(P＜0.05).Body weight reduced in the TPL group compared with that in the Sham group at week 2(P＜0.01).There was no significant difference in body weight between the TPL and UUO groups.BUN levels did not differ significantly between the three groups.Compared with the sham group,the SCr level in the UUO group significantly increased[(15.680±1.508)μmol/L](P＜0.01).A reduction in SCr level was observed following TPL administration[(12.550±3.004)μmol/L](P＜0.05).HE staining showed that the renal tubules of mice in the UUO group were significantly dilated and atrophic,with interstitial edema and increased inflammatory cell infiltration,while the pathological damage of renal tissues was significantly alleviated after TPL treatment.Masson staining revealed that interstitial collagen deposition significantly increased in the UUO group(36.350±5.183)％(P＜0.01)and reduced after TPL administration(20.820±3.290)％(P＜0.01).Immunohistochemistry results demonstrated that the IOD levels of α-SMA(1.233±0.045)and Fn(1.337±0.045)were higher in UUO group mice than in the sham group,while the IOD levels of α-SMA(1.047±0.025)and Fn(1.113±0.021)were lower in the TPL group than in the UUO group(P＜0.05).Western blotting analysis indicated that the expression levels of NLRP3,cGSDMD,IL-1β and IL-18 in the UUO group mice were higher than those in the sham group,while the protein expression levels of the above-mentioned indicators significantly decreased after TPL treatment(P＜0.05).Conclusion TPL ameliorates renal interstitial fibrosis in mice with UUO by inhibiting NLRP3-mediated pyroptosis.

Objective:To compare the pregnancy outcomes of surviving fetuses in monochorionic diam-niotic(MCDA)twin pregnancies after selective feticide or spontaneous single intrauterine fetal demise(sIUFD),and to explore the influencing factors of prognosis.Methods:A total of 219 cases of intra-uterine death of one fetus in MCDA twin pregnancies admitted to Peking University Third Hospital from September 2010 to August 2021 were collected.According to the mode of fetal death,they were divided into the spontaneous sIUFD group(120 cases)and the selective feticide group(99 cases).Data on the maternal conditions during pregnancy,the situation of the intrauterine-dead fetus,and pregnancy out-comes were collected for retrospective case-analysis.Results:The live-birth rates of surviving fetuses in the spontaneous sIUFD group and the selective feticide group were 85.0％and 81.8％respectively,and the total perinatal survival rates of surviving fetuses were 73.3％and 81.8％respectively,and there were no statistically significant differences.Compared with the spontaneous sIUFD group,the selective feticide group had a greater gestational week at delivery,and lower rate of preterm birth before 37 weeks,neonatal asphyxia,and early neonatal mortality.Using the gestational week at delivery as the outcome variable,Cox regression analysis showed that the mode of fetal death was not a risk factor affecting the gestational week at delivery of the surviving fetus,while gestational hypertension and the gestational week of fetal death were independent risk factors affecting the gestational week at delivery of the surviving fetus.Using preterm birth before 37 weeks,intrauterine death of the surviving fetus,and abnormal neonatal cranial ultrasound as outcome variables respectively,unconditional logistic regression analysis showed that the mode of fetal death,the gestational week of fetal death,the position of the dead fetus,and fetal complications were independent risk factors affecting the outcomes of the above-mentioned survi-ving fetuses.According to the results of the univariate analysis,the above risk factors were included in the multivariate regression analysis,and the results were the same as those of the univariate analysis.Conclusion:For MCDA twin pregnancy patients with severe twin-related complications,the prognosis of surviving fetuses after selective feticide is better.The proactive intrauterine intervention and treatment are of great significance for improving the prognosis of surviving fetuses.

Objective To investigate the effect of triptolide(TPL)on renal interstitial fibrosis in mice with unilateral ureteral obstruction(UUO)and its mechanism.Methods Six male C57BL/6J mice were randomly selected as the sham group,and 12 mice with UUO modeling were randomly divided into the model group(UUO)and the triptolide group(TPL).Changes in serum creatinine(SCr),blood urea nitrogen(BUN),and body weight were compared among the groups.Renal tissue specimens were collected at 14 d after UUO for HE and Masson staining.Immunohistochemistry staining was performed to observe the expression of α-smooth muscle actin(α-SMA)and fibronectin(Fn)in kidney tissues.Western blotting analysis was used to detect the protein expression levels of nucleotide combined with structure of oligomerization domain receptor protein 3(NLRP3),GSDMD,cGSDMD,IL-1β and IL-18.Results At week 1,the body weight of mice in the UUO and TPL groups significantly decreased compared with that in the sham group(P＜0.05).Body weight reduced in the TPL group compared with that in the Sham group at week 2(P＜0.01).There was no significant difference in body weight between the TPL and UUO groups.BUN levels did not differ significantly between the three groups.Compared with the sham group,the SCr level in the UUO group significantly increased[(15.680±1.508)μmol/L](P＜0.01).A reduction in SCr level was observed following TPL administration[(12.550±3.004)μmol/L](P＜0.05).HE staining showed that the renal tubules of mice in the UUO group were significantly dilated and atrophic,with interstitial edema and increased inflammatory cell infiltration,while the pathological damage of renal tissues was significantly alleviated after TPL treatment.Masson staining revealed that interstitial collagen deposition significantly increased in the UUO group(36.350±5.183)％(P＜0.01)and reduced after TPL administration(20.820±3.290)％(P＜0.01).Immunohistochemistry results demonstrated that the IOD levels of α-SMA(1.233±0.045)and Fn(1.337±0.045)were higher in UUO group mice than in the sham group,while the IOD levels of α-SMA(1.047±0.025)and Fn(1.113±0.021)were lower in the TPL group than in the UUO group(P＜0.05).Western blotting analysis indicated that the expression levels of NLRP3,cGSDMD,IL-1β and IL-18 in the UUO group mice were higher than those in the sham group,while the protein expression levels of the above-mentioned indicators significantly decreased after TPL treatment(P＜0.05).Conclusion TPL ameliorates renal interstitial fibrosis in mice with UUO by inhibiting NLRP3-mediated pyroptosis.

Objective:To investigate the risk factors for severe postpartum hemorrhage (SPPH) during vaginal delivery of twin pregnancy.Methods:A retrospective analysis was conducted on clinical data from twin pregnancies ≥28 weeks′ gestation undergoing vaginal delivery at Peking University Third Hospital between January 2016 and December 2023. The twin pregnant women were divided into the SPPH group (postpartum hemorrhage ≥1 000 ml within 24 hours) with 22 cases and the non-SPPH group with 171 cases. The differences between the two groups were compared and the risk factors for SPPH were analyzed.Results:(1) The incidence of SPPH during vaginal delivery in twin pregnancies was 11.4% (22/193). The causes of SPPH included 12 cases (54.5%, 12/22) of simple uterine atony, 4 cases (18.2%, 4/22) of uterine atony combined with vaginal lacerations after forceps delivery, and 6 cases (27.3%, 6/22) of uterine atony combined with placental factors. (2) The age and postpartum hospital stay in the SPPH group were significantly higher than those in the non-SPPH group (all P<0.05). Compared to the non-SPPH group, the proportion of hypertensive disorders in pregnancy, accreta placenta implantation, and anemia in the SPPH group were significantly increased, and the birth weight of newborn 1st, the sum of the birth weights of two newborns, the duration of the second stage of labor, and the proportion of labor followed induction were also significantly increased (all P<0.05). (3) Multivariate analysis showed that age ≥38 years ( OR=16.785, 95% CI: 2.679-105.166; P=0.003), the second stage of labor ≥90 minutes ( OR=9.670, 95% CI: 2.532-36.930; P=0.001), hypertensive disorders in pregnancy ( OR=5.945, 95% CI: 1.702-20.761; P=0.005), and anemia ( OR=8.048, 95% CI: 2.086-31.049; P=0.002) were independent risk factors for SPPH in twin pregnancies during vaginal delivery. Conclusions:Anemia should be actively corrected during twin pregnancy. For twin pregnant women with advanced age, hypertensive disorders in pregnancy, or other risk factors of SPPH, if vaginal delivery is chosen, attention should be paid to the management of labor duration, dynamic assessment of the risk of postpartum hemorrhage, and proactive measures should be taken to ensure a smooth vaginal delivery and effectively reduce the incidence of SPPH.

Space radiation is the most important environmental harmful factor in long-term manned spaceflight and deep space exploration, and it may produce deterministic and stochastic effects on tissues and organs. In-depth research into the biological effects, mechanisms, and protective measures of space radiation is essential and serves as an important foundation for exploring radiation biology and promoting major manned space projects. Firstly, this review introduces the spatiotemporal distribution characteristics of space radiation during low-earth orbit flights, manned lunar landings, and deep space exploration missions, as well as the health risks and challenges it posed to astronauts. Then, it discusses medical requirements and exposure limits, risk assessment, and protection technologies included in the space radiation protection system established internationally and over 30 years of Chinese manned spaceflight departments. Finally, it outlines the subsequent work and prospects for further research.

Acute myeloid leukemia (AML) is a disease caused by abnormal cloning of hematopoietic stem cells in the bone marrow, which leads to accumulation of a large number of abnormally differentiated myeloid cells. It is difficult to cure by traditional treatment. The successful application of chimeric antigen receptor T cell (CAR-T) immunotherapy indicates that the treatment of hematological tumors has entered a new stage of precision immunotherapy. However, CAR-T immunotherapy has been found to have many problems in clinical applications, including long treatment cycle, expensive prices, off-target effects, cytokine release syndrome, etc. Therefore, it is necessary to expand the application of CAR or adopt improved measures to enhance the therapeutic effect. This article reviews the new strategies for genetic engineering modification of CAR immune cells and the research progress and application of in situ programming to generate CAR-T, and besides, briefly introduces the new methods about the delivery of gene drugs in vivo, aiming to provide new ideas and theoretical basis for expanding and improving the application of precision immunotherapy in AML.

Objective To explore the effect of bone marrow injury by simulating the radiation from solar particle events in order to address the radiation limit and assess risks during manned deep space exploration.Methods In line with solar particle events(the main component was protons),BALB/c mice(48 mice per group)were irradiated with 90 MeV protons at the doses of 0,0.1,0.3,0.5,1 and 2 Gy.At 3 and 7 days after irradiation.Routine blood counters were employed to detect peripheral blood changes,Giemsa staining was used to detect the ratio of granulocytes to erythrocytes in bone marrow,and flow cytometry was adopted to detect the proportion of bone marrow stem cells,cell subsets and apoptosis before the dose-response relationship and threshold were analyzed.Results In the dose range of 0.1 to 2 Gy,the number of peripheral blood white blood cells and lymphocytes decreased at 3 and 7 days after irradiation and the ratio of granulocytes to erythrocytes in bone marrow and bone marrow cell subsets were abnormal as the dose increased.Seven days after irradiation,the platelet count decreased.The minimum dose that caused significant changes was 0.5 Gy,13 models with dose-response relationships were obtained,and the minimum values of ED25,ED50 and ED63 were 0.25,0.58 and 0.76 Gy,respectively.Conclusion A total of 13 dose-response relationship models of proton-induced bone marrow injury in mice have been obtained,and the dose threshold of proton-induced bone marrow injury ranges from 0.25 to 0.76 Gy.