Objective:To study the characteristics of vaginal microbiota in pregnant women with premature rupture of membranes (PROM) and to establish prediction models for PROM.Methods:This study involved 35 women with preterm premature rupture of membranes (PPROM), 180 with term premature rupture of membranes (TPROM) and 255 term birth cases without premature rupture of membranes (TBWPROM, control group). The V3-V4 hypervariable region sequences in the vaginal samples collected at 16-28 weeks of gestation were detected by 16S rRNA gene next-generation sequencing. The differences in Alpha and Beta diversity, and the attributes and metabolic function prediction of each recognized species among the three groups were analyzed. Subsequently, a random forest model was used to establish the prediction models for PROM using vaginal microbiota species and environmental risk factors.Results:Compared with the control group, the Alpha diversity of the PPROM group was higher (Observed features, P=0.022; Faith_pd index, P=0.024) and Beta diversity was also significantly different (Unweighted UniFrac, P=0.010; Jaccard index, P=0.008). In PPROM cases, Megasphaera genomosp. typeⅠ was significantly increased ( P=0.017) and Lactobacillus mulieris was significantly decreased ( P=0.003). In the patients with TPROM, Megasphaera was significantly increased ( P=0.009) and Lactobacillus mulieris was significantly decreased ( P=0.002). In terms of functional pathways, sulfur oxidation ( P=0.021), methanogenesis from acetate ( P=0.036), L-histidine biosynthesis ( P=0.009), adenosylcobalamin biosynthesis ( P=0.041) and fucose degradation ( P=0.001) were significantly increased in patients with PPROM; L-histidine biosynthesis ( P<0.001) and fucose degradation ( P=0.030) were significantly increased in patients with TPROM. The prediction models were established using the random forest model with vaginal microbiota species and environmental risk factors and the prediction model for PPROM performed well [AUC: 0.739 (95%CI: 0.609-0.869), sensitivity: 0.928, specificity: 0.659, positive predictive value: 0.750, negative predictive value: 0.906], which had a certain reference value. Conclusions:Vaginal microbiota might be related to the development and progression of PROM. Studying the differences in vaginal microbiota might provide a new idea for the prevention and treatment of PROM. Functional prediction provided a direction for further research on the mechanism of PROM. The established prediction model could prevent the occurrence of PPROM and promote maternal and infant health.

Objective:To study the characteristics and influencing factors of vaginal microbiota in normal pregnant women.Methods:This study was based on a cohort of pregnant women established in Anqing Municipal Hospital Affiliated to Anhui Medical University from February 2018 to February 2020. Vaginal samples of normal pregnant women who met the inclusion and exclusion criteria were ordered by the gestational weeks at sampling. Five samples were randomly selected from each gestational week group and if the samples were less than five, all samples were included. Sequencing of the V3-V4 region of the 16S rRNA gene was performed. Dominant species were analyzed by MicrobiomeAnalyst. Alpha diversity was measured with Chao1, Observed Features, Shannon diversity, Simpson diversity, Faith_pd and Pielou′s Evenness. The dominant status of Lactobacillus was also described and compared. Multiple linear regression and logistic regression were used to analyze the factors influencing vaginal microbiota. Analysis of variance and Kruskal Wallis test were used for statistical analysis of continuous variables, and Chi-square test and Fisher′s exact test were used for categorical data. The differences were considered statistically significant when the P value was less than 0.05. Results:This study enrolled 91 pregnant women (91 vaginal samples) with an average age of (27.37±3.60) years. There were 18, 56 and 17 vaginal samples collected at the median gestational age of 11.93 weeks (the first trimester), 19.43 weeks (the second trimester) and 38.29 weeks (the third trimester), respectively. The relative abundance of Firmicutes and Lactobacillus was 91.30% and 87.67%, respectively. Lactobacillus iners and Lactobacillus crispatus had a relative abundance of 43.95% and 36.33%, respectively. Moreover, Lactobacillus iners-dominated vaginal microbiota was detected in all trimesters. The number of samples with high relative abundance of Lactobacillus iners gradually decreased with gestational age. Lactobacillus crispatus-dominated vaginal microbiota was found in the second and third trimesters and the number of samples with high relative abundance gradually increased during pregnancy. The Alpha diversity of vaginal microbiota had a decreasing trend during the gestation. There were significant differences in Pielou′s Evenness diversity index of vaginal microbiota between different smoking groups ( P<0.05) and in Shannon diversity index between different drinking groups ( P<0.05). There were significant differences in Chao1, Observed Features and Faith_pd diversity index of vaginal microbiota between pregnant women with different education ( P<0.05) and in Shannon and Simpson diversity index between different income groups ( P<0.05). Conclusions:Vaginal microbiota was dominated by Lactobacillus in normal pregnant women. The dominance of Lactobacillus iners gradually decreased, while that of Lactobacillus crispatus increased during gestation. In normal pregnant women, the Alpha diversity of vaginal microbiota was correlated with smoking, drinking, education and family annual income. Smoking cessation and drinking before pregnancy were related to lower Alpha diversity of vaginal microbiota in pregnant women, while lower education and higher family income were associated with higher Alpha diversity.

Objective:This study aimed to explore the clinical application value of the indication selection criteria for bi-pedicled deep inferior epigastric arterial perforator flap(DIEP) versus pedicled transverse rectus abdominis myocutaneous flap(TRAM) combined with DIEP for breast reconstruction.Methods:The clinical data of patients who underwent delayed bi-pedicled abdominal flap breast reconstruction after breast cancer surgery in the Department of Oncoplastic and Reconstructive Breast Surgery and Department of Mammoplasty, Plastic Surgery Hospital, Chinese Academy of Medical Sciences from January 2008 to April 2022 were retrospectively analyzed. According to the indications for each procedure, corresponding blood supply source was selected. Subsequently, patients were divided into two groups: bi-pedicled DIEP group and pedicled TRAM+ DIEP combined flap group according to the type of blood supply source. The indication selection criteria for pedicled TRAM+ DIEP combined flap was as follows: lack of two groups of recipient vessels; no dominant perforator in the abdominal donor site; previous abdominal liposuction or abdominal surgery with large dissection range and severe scar; patients were unable to tolerate prolonged surgery or had high risk factors for microsurgery. A comparison of breast reconstruction surgery characteristics was conducted between the two groups. Independent-samples t-test, rank sum test, Chi-square test and Fisher’s exact probability method were used to analyze various data including age, body mass index (BMI), time interval between breast cancer surgery and breast reconstruction surgery, history of radiotherapy, history of chemotherapy, history of smoking, history of lower abdominal surgery, history of hypertension, original surgical incision type, length and width of flap, hospitalization length, preoperative and postoperative conditions, as well as postoperative complications. Statistical significance was defined at P<0.05. Results:A total of 54 patients who underwent unilateral breast reconstruction were included in this study with a mean age of 42.2 years (range, 30-59 years). The pedicled TRAM+ DIEP combined flap group consisted of 21 patients with a mean age of 42.7 years (range, 33-56 years) while the bi-pedicled DIEP group comprised 33 patients with a mean age of 41.8 years (30-59 years). Out of the 54 patients, a total of 38 were eventually followed up, comprising 14 in the pedicled TRAM+ DIEP combined flap group and 24 in the bi-pedicled DIEP group. The average follow-up duration for the pedicled TRAM+ DIEP combined flap group was 42 months (range, 6-69 months). Abdominal bulge occurred in one patient, while another patient experienced abdominal hernia. The average follow-up duration for the bi-pedicled DIEP group was 47 months (6-179 months), with no reported cases of abdominal bulge or abdominal hernia. There were no statistically significant differences observed between the two groups regarding age, BMI, time interval between breast cancer surgery and breast reconstruction surgery, history of radiotherapy or chemotherapy, history of smoking, history of lower abdominal surgery, history of hypertension, original surgical incision type, length and width of flap, hospitalization length or time to ambulation (all P>0.05). However, there was a statistically significant difference noted in duration of surgery between the pedicled TRAM+ DIEP combined flap group and bi-pedicled DIEP group [6.0(5.5-6.5) hours vs. 8.5(8.0-8.8) hours] ( P<0.01). Comparison analysis revealed no statistically significant differences in terms of partial flap necrosis (0/21 vs. 1/33), abdominal incision dehiscence (2/21 vs. 2/33), abdominal bulge (1/14 vs. 0 /24) or abdominal hernia (1/1 vs. 0/24) between the two groups ( P>0.05). Conclusion:For patients who needed bilateral vascular pedicled lower abdominal wall for breast reconstruction, utilizing a pedicled TRAM+ DIEP combined flap did not increase surgical complication risks. The proposed indication selection criteria for using a pedicled TRAM + DIEP combined flap outlined in this study could serve as guidance when choosing methods for bi-pedicled abdominal flap breast reconstruction.

Objective:This study aimed to explore the clinical application value of the indication selection criteria for bi-pedicled deep inferior epigastric arterial perforator flap(DIEP) versus pedicled transverse rectus abdominis myocutaneous flap(TRAM) combined with DIEP for breast reconstruction.Methods:The clinical data of patients who underwent delayed bi-pedicled abdominal flap breast reconstruction after breast cancer surgery in the Department of Oncoplastic and Reconstructive Breast Surgery and Department of Mammoplasty, Plastic Surgery Hospital, Chinese Academy of Medical Sciences from January 2008 to April 2022 were retrospectively analyzed. According to the indications for each procedure, corresponding blood supply source was selected. Subsequently, patients were divided into two groups: bi-pedicled DIEP group and pedicled TRAM+ DIEP combined flap group according to the type of blood supply source. The indication selection criteria for pedicled TRAM+ DIEP combined flap was as follows: lack of two groups of recipient vessels; no dominant perforator in the abdominal donor site; previous abdominal liposuction or abdominal surgery with large dissection range and severe scar; patients were unable to tolerate prolonged surgery or had high risk factors for microsurgery. A comparison of breast reconstruction surgery characteristics was conducted between the two groups. Independent-samples t-test, rank sum test, Chi-square test and Fisher’s exact probability method were used to analyze various data including age, body mass index (BMI), time interval between breast cancer surgery and breast reconstruction surgery, history of radiotherapy, history of chemotherapy, history of smoking, history of lower abdominal surgery, history of hypertension, original surgical incision type, length and width of flap, hospitalization length, preoperative and postoperative conditions, as well as postoperative complications. Statistical significance was defined at P<0.05. Results:A total of 54 patients who underwent unilateral breast reconstruction were included in this study with a mean age of 42.2 years (range, 30-59 years). The pedicled TRAM+ DIEP combined flap group consisted of 21 patients with a mean age of 42.7 years (range, 33-56 years) while the bi-pedicled DIEP group comprised 33 patients with a mean age of 41.8 years (30-59 years). Out of the 54 patients, a total of 38 were eventually followed up, comprising 14 in the pedicled TRAM+ DIEP combined flap group and 24 in the bi-pedicled DIEP group. The average follow-up duration for the pedicled TRAM+ DIEP combined flap group was 42 months (range, 6-69 months). Abdominal bulge occurred in one patient, while another patient experienced abdominal hernia. The average follow-up duration for the bi-pedicled DIEP group was 47 months (6-179 months), with no reported cases of abdominal bulge or abdominal hernia. There were no statistically significant differences observed between the two groups regarding age, BMI, time interval between breast cancer surgery and breast reconstruction surgery, history of radiotherapy or chemotherapy, history of smoking, history of lower abdominal surgery, history of hypertension, original surgical incision type, length and width of flap, hospitalization length or time to ambulation (all P>0.05). However, there was a statistically significant difference noted in duration of surgery between the pedicled TRAM+ DIEP combined flap group and bi-pedicled DIEP group [6.0(5.5-6.5) hours vs. 8.5(8.0-8.8) hours] ( P<0.01). Comparison analysis revealed no statistically significant differences in terms of partial flap necrosis (0/21 vs. 1/33), abdominal incision dehiscence (2/21 vs. 2/33), abdominal bulge (1/14 vs. 0 /24) or abdominal hernia (1/1 vs. 0/24) between the two groups ( P>0.05). Conclusion:For patients who needed bilateral vascular pedicled lower abdominal wall for breast reconstruction, utilizing a pedicled TRAM+ DIEP combined flap did not increase surgical complication risks. The proposed indication selection criteria for using a pedicled TRAM + DIEP combined flap outlined in this study could serve as guidance when choosing methods for bi-pedicled abdominal flap breast reconstruction.

Objective:To construct polydopamine-coated silicified collagen(SC@PDA)by polymerization of dopamine,and to ex-plore its biological safety and photothermal antibacterial properties.Methods:Dopamine was coated on the surface of silicified colla-gen by polymerization reaction to construct SC@PDA.The surface morphology of SC@PDA was observed by SEM and TEM,the silic-ic acid release was detected by silicic acid release experiment,and the photothermal properties of SC@PDA were detected by 808 nm laser irradiation and infrared thermography.The biocompatibility of SC@PDA was evaluated by CCK-8 assay with rat bone marrow mesenchymal stem cells and acute systemic toxicity test in SD rats.The materials were co-cultured with Staphylococcus aureus(S.au-reus)and Escherichia coli(E.coli)respectively for 6 h followed by 808 nm laser irradiation and culture for 6 h,and then the antibac-terial rate of the materials was calculated by absorbance detection.Finally,the anti-infection effect was observed 7 days after implan-tation in the rat femoral defect infection model of SD rats.Results:SC@PDA maintained the silicic acid release characteristics of si-licified collagen and had good biocompatibility and good photothermal property.In vitro and in vivo antibacterial experiments showed that SC@PDA had good antibacterial activity without cytotoxicity and acut system toxicity.Conclusion:SC@PDA has biocompatibili-ty and the dopamine coating endows the silicified collagen scaffold with excellent photothermal antibacterial properties.

Due to the flaws inherited in synchronicity, statistical association and survivor bias on variables under measurement, a common 'consensus’ has been reached on "cross-sectiional studies (CSS) can lead to failure on causal inference". In this paper, under both causal thinking and diagram, the real and measured cross-sections are clearly defined that these two concepts only exist theoretically. In real CSS research, the temporal orders of measured variables are all non-synchronic, equivalent to the assumption that measurement variables are independent to each other, or there is no differentiated classification bias. Similar to cumulative case-control or historical cohort studies, both exposure and outcome that exist or occur before their measurements in cross-sectional studies, are actions of historical reconstruction or doing 'Archaeology’. One of the common preconditions for causal inference in such studies is that: there must be a causal relation between the measured variables and their historical counterparts. The measured variables are all agents of their corresponding real counterparts, and the temporal orders are not that important in causal inference. It is necessary to better understand the analytic role of the CSS.