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 observe the impact of hip synovitis on the long-term outcomes of free vascularized fibular grafting(FVFG)for osteonecrosis of femoral head(ONFH).Methods·Between October 2001 and December 2013,370 patients diagnosed with ONFH(556 hips)underwent FVFG.Preoperative synovitis was assessed using magnetic resonance imaging(MRI)and quantified with the Hip Inflammation MRI Scoring System(HIMRISS).Patients were divided into no synovitis group,moderate synovitis group,and severe synovitis group.Harris hip scores and the incidence of total hip arthroplasty were collected with an average follow-up duration of 90.5 months(range:5-215 months).Hip survival failure(defined as a Harris hip score lower than 80 at the final follow-up or the occurrence of total hip arthroplasty)was calculated.Multivariable Cox regression analysis was adopted to compare the influence of different degrees of synovial inflammation on long-term prognosis.Results·The proportion of hip survival failure was 28.0％in patients without synovitis and 28.5％in those with moderate synovitis,whereas it was significantly higher(60.4％)in patients with severe synovitis.The results of multivariable Cox regression analysis showed that severe synovitis was an independent risk factor for poor prognosis(HR 2.06,95％CI 1.21-3.53)after adjusting for age,gender,education level,marital status,ONFH type,affected side of ONFH,smoking history,baseline Harris hip score and other hip MRI-based covariates(collapse,bone marrow edema,and degeneration).Conclusion·Severe synovitis in patients with ONFH significantly increases the failure rate of hip preservation after FVFG,and the severity of synovitis should be considered in surgical decision-making.

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 observe the impact of hip synovitis on the long-term outcomes of free vascularized fibular grafting(FVFG)for osteonecrosis of femoral head(ONFH).Methods·Between October 2001 and December 2013,370 patients diagnosed with ONFH(556 hips)underwent FVFG.Preoperative synovitis was assessed using magnetic resonance imaging(MRI)and quantified with the Hip Inflammation MRI Scoring System(HIMRISS).Patients were divided into no synovitis group,moderate synovitis group,and severe synovitis group.Harris hip scores and the incidence of total hip arthroplasty were collected with an average follow-up duration of 90.5 months(range:5-215 months).Hip survival failure(defined as a Harris hip score lower than 80 at the final follow-up or the occurrence of total hip arthroplasty)was calculated.Multivariable Cox regression analysis was adopted to compare the influence of different degrees of synovial inflammation on long-term prognosis.Results·The proportion of hip survival failure was 28.0％in patients without synovitis and 28.5％in those with moderate synovitis,whereas it was significantly higher(60.4％)in patients with severe synovitis.The results of multivariable Cox regression analysis showed that severe synovitis was an independent risk factor for poor prognosis(HR 2.06,95％CI 1.21-3.53)after adjusting for age,gender,education level,marital status,ONFH type,affected side of ONFH,smoking history,baseline Harris hip score and other hip MRI-based covariates(collapse,bone marrow edema,and degeneration).Conclusion·Severe synovitis in patients with ONFH significantly increases the failure rate of hip preservation after FVFG,and the severity of synovitis should be considered in surgical decision-making.

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.

Gene editing technology has been a hotspot in the field of biotechnology. CRISPR/Cas systems are efficient gene editing tools because of its specificity, simplicity and flexibility, these features enabled the rapid application of CRISPR/Cas systems in a variety of organisms. Moreover, the combination of transcriptional activator with dead Cas protein can achieve specific regulation of gene expression at the transcription level, which has made important contributions to the development of biotechnology in medical and agriculture. Overexpression of foreign genes is a common method to verify gene function and regulation. However, due to the limitation of vector capacity, it is difficult to achieve overexpression of multiple genes. CRISPR/Cas9 activation system can regulate the expression of multiple genes under the guidance of different guide RNAs to verify gene functions at the regulatory level. This review summarizes the composition of the CRISPR/Cas9 activation system and different activation strategies, and summarizes solutions for excessive activation. It may facilitate the application of CRISPR/Cas9 activation system in genetic improvement of cotton and herbicide resistance research.
Biotechnology ; CRISPR-Cas Systems/genetics* ; Gene Editing ; Phenotype ; RNA, Guide, Kinetoplastida/metabolism*

Objective:To summarize the pregnancy outcome of monochorionic triamniotic (MCTA) triplet pregnancy and its relationship with multifetal pregnancy reduction.Methods:This study retrospectively recruited 23 women with MCTA pregnancy who delivered at Peking University Third Hospital from January 1, 2012, to January 1, 2020. All 23 cases received regular prenatal examination at our hospital from the first trimester, who were divided into two groups: selective fetal reduction group (randomly reduced one fetus, n=8) and expectant group ( n=15). Pregnancy outcome was described in all participants, differences in maternal age, gestational weeks and outcomes were compared between the two groups. The selective fetal reduction group was further divided into two subgroups: first-trimester vacuum aspiration group ( n=3) and second-trimester radiofrequency ablation group ( n=5), to evaluate the differences in pregnancy outcomes. Two independent samples- t test and Fisher's exact test were used as statistical methods. Results:(1) There was no significant difference in the gestational weeks at the end of the pregnancy [(31.7±4.1) vs (28.8±8.8) weeks], preterm delivery after 32 weeks (9/15 vs 4/8), at least two surviving children (12/15 vs 4/8) and at least one surviving child (13/15 vs 5/8) between the expectant group and the selective fetal reduction group (all P>0.05). One case with twin-twin transfusion syndrome in the expectant group underwent fetoscopic surgery at 19 weeks of gestation and delivered three live infants through cesarean section at 33 +2 weeks due to premature rupture of membranes. One case with twin reversed arterial perfusion sequence at 17 weeks of gestation refused fetal reduction and gave birth to a child at 33 weeks when one fetus's heart stopped beating and one was acardia. (2) The first-trimester vacuum aspiration group and the second-trimester radiofrequency ablation group showed no significant differences in the average gestational weeks at the end of the pregnancy [(28.5±7.6) vs (28.9±10.4) weeks, t=1.145, P>0.05], or the rate of at least one (2/3 vs 3/5, Fisher's exact test, P>0.05) or two surviving children (2/3 vs 2/5, Fisher's exact test, P>0.05). No postoperative infection or amniotic fluid leakage was reported in the subgroups. Conclusions:The pregnancy outcome of MCTA triplet with fetal reduction is not different with expectant group.

Objective:To clarify the infection and epidemic characteristics of the human metapneumovirus (HMPV) in Chinese patients with febrile respiratory syndrome (FRS), and to provide important baseline data for clinical diagnosis, treatment, prevention and control of HMPV-induced respiratory tract diseases in China.Methods:FRS cases from January 2009 to June 2021 in 9 provinces in China, including Beijing, Hebei, Jilin, Shandong, Shaanxi, Xinjiang, Anhui, Guangdong, Hunan were retrospectively analyzed for their respiratory samples, clinical and epidemic data.The respiratory samples were detected for HMPV by quantitative real-time PCR.Results:A total of 11 660 cases were tested for HMPV, involving 296 (2.54%) HMPV-positive cases.Among 296 HMPV-positive cases, 218 were single HMPV infection, and 78/296 (26.35%) were co-infected with one or more respiratory viruses.HMPV mainly affected children under 5 years of age (3.10%), and in this population, the proportion of pneumonia in HMPV co-infection cases was significantly higher than that of single HMPV infection.HMPV could be detected all year round, which was more popular in winter and spring, with the peak of HMPV epidemic in March.Conclusions:HMPV is one of the important pathogens causing acute respiratory infection in children, showing a clear seasonal epidemic.HMPV can be infected alone or in combination with other respiratory viruses, which may increase the risk of pneumonia in children.

Objective To explore the measurement of(1,3)-β-D glucan in plasma for the diagnosis of pulmonary fungal infections in pulmonary tuberculosis patients. Methods 40 pulmonary tuberculosis patients with pulmonary fungal infections in Guangzhou chest hospital from January 2015 to December 2015 were enrolled as a test group,among which 35 were confirmed and 5 were suspected pulmonary fungal infections. 52 pulmonary tuber-culosis patients without fungal infections were selected as a control group.(1,3)-β-D glucan content(G test)in this 92 patients plasma were detected. The results of G tests were compared with those from etiological diagnosis to assess the performance of G test. Results 13 strains of candida albicans,13 strains of aspergillus,2 strains of candida tropicalis,2 strains of candida glabrata and 6 strains of other yeast were obtained from patients of test group,but no fungal identified from those of control group. The median of G test in test group and in control group was 126.1 and 29.56 pg/mL,respectively,the level in test group was significantly higher than that in control group (P<0.001). 35 cases were identified as positive and 5 were negative in test group by G test ,while 41 cases were identified as negative and 11 were positive in control group. The sensitivity,specificity,positive predictive value, negative predictive value ,concordance and Youden index of G test were 87.5%,78.85%,76.09%,89.13%, 82.6%and 0.663,respectively. Conclusions Candida albicans and aspergillus are more common pathogens than the other fungi isolated from pulmonary tuberculosis patients with pulmonary fungal infection. G test ,used in pul-monary tuberculosis with pulmonary fungal infections diagnosis,is reliable and fast,and has a higher sensitivity, specificity and accuracy.

BACKGROUND:The peri-implant bone absorption is closely related to the repair effect. OBJECTIVE:To compare the effects of three kinds of dental implant systems on the peri-implant bone absorption. METHODS:116 patients who underwent the dental implant systems were col ected, including 46 cases with 3I implant system, 40 cases with ITI implant system and 30 cases with BLB implant system. The peri-implant bone absorption, sulcus bleeding index and periodontal probing depth of three groups were detected at 1, 3, 6, 9 and 12 months after implantation, respectively. RESULTS AND CONCLUSION:The peri-implant bone absorption of three groups within 1 year after implantation was in a rise, and the bone absorption of BLB group was significantly higher than that of ITI and 3I groups at 3 and 12 months after implantation (P<0.05). Compared with the natural teeth, the gingival sulcus bleeding index of three groups were al increased at different time points after implantation;the gingival sulcus bleeding index of BLB group was significantly higher than that of natural teeth at 6 months after implantation (P<0.05);the gingival sulcus bleeding index of three groups were significantly higher than that of natural teeth at 9 months after implantation (P<0.05). The periodontal probing depth of three groups showed an ascending trend at 6 months after implantation;the periodontal probing depth of three groups was higher than that of natural teeth at different time points after implantation, which exhibited significant differences at 6 and 9 months after implantation (P<0.05). In conclusion, three kinds of dental implant systems exhibit differet effects on the peri-implant bone absorption, but al achieve excel ent clinical efficacies.