T7 RNA polymerase (T7 RNAP) is one of the simplest known RNA polymerases. Its unique structural features make it a critical model for studying the mechanisms of RNA synthesis. This review systematically examines the static crystal structure of T7 RNAP, beginning with an in-depth examination of its characteristic “thumb”, “palm”, and “finger” domains, which form the classic “right-hand-like” architecture. By detailing these structural elements, this review establishes a foundation for understanding the overall organization of T7 RNAP. This review systematically maps the functional roles of secondary structural elements and their subdomains in transcriptional catalysis, progressively elucidating the fundamental relationships between structure and function. Further, the intrinsic flexibility of T7 RNAP and its applications in research are also discussed. Additionally, the review presents the structural diagrams of the enzyme at different stages of the transcription process, and through these diagrams, it provides a detailed description of the complete transcription process of T7 RNAP. By integrating structural dynamics and kinetics analyses, the review constructs a comprehensive framework that bridges static structure to dynamic processes. Despite its advantages, T7 RNAP has a notable limitation: it generates double-stranded RNA (dsRNA) as a byproduct. The presence of dsRNA not only compromises the purity of mRNA products but also elicits nonspecific immune responses, which pose significant challenges for biotechnological and therapeutic applications. The review provides a detailed exploration of the mechanisms underlying dsRNA formation during T7 RNAP catalysis, reviews current strategies to mitigate this issue, and highlights recent progress in the field. A key focus is the semi-rational design of T7 RNAP mutants engineered to minimize dsRNA generation and enhance catalytic performance. Beyond its role in transcription, T7 RNAP exhibits rapid development and extensive application in fields, including gene editing, biosensing, and mRNA vaccines. This review systematically examines the structure-function relationships of T7 RNAP, elucidates the mechanisms of dsRNA formation, and discusses engineering strategies to optimize its performance. It further explores the engineering optimization and functional expansion of T7 RNAP. Furthermore, this review also addresses the pressing issues that currently need resolution, discusses the major challenges in the practical application of T7 RNAP, and provides an outlook on potential future research directions. In summary, this review provides a comprehensive analysis of T7 RNAP, ranging from its structural architecture to cutting-edge applications. We systematically examine: (1) the characteristic right-hand domains (thumb, palm, fingers) that define its minimalistic structure; (2) the structure-function relationships underlying transcriptional catalysis; and (3) the dynamic transitions during the complete transcription cycle. While highlighting T7 RNAP’s versatility in gene editing, biosensing, and mRNA vaccine production, we critically address its major limitation—dsRNA byproduct formation—and evaluate engineering solutions including semi-rationally designed mutants. By synthesizing current knowledge and identifying key challenges, this work aims to provide novel insights for the development and application of T7 RNAP and to foster further thought and progress in related fields.

The incidence of knee osteoarthritis(KOA)is in-creasing year by year,seriously affecting patients'health.Mes-enchymal stem cells are multipotent cells with multiple differen-tiation functions.The extracellular vesicles released by these cells can carry various"cargo"to corresponding cells and tis-sues,exerting biological functions.They have shown great clini-cal potential in the treatment of KOA.This study reviews the therapeutic effects and mechanisms of extracellular vesicles se-creted by mesenchymal stem cells from different tissues such as bone marrow,adipose tissue,and synovium in KOA.It is found that miRNA is an important biological component in exerting therapeutic effects.The study also discusses the research pro-gress of engineered extracellular vesicles in KOA,pointing out the current challenges in clinical application,such as standard-ized acquisition of extracellular vesicles and difficulties in targe-ted action,aiming to provide a certain reference for the basic re-search and clinical application of extracellular vesicle therapy for KOA.

Aim To explore the improvement effect of Bazi Bushen capsule on thymic degeneration in SAMP6 mice and the possible mechanism.Methods Twenty 12 week old male SAMP6 mice were randomly divided into the model group(SAMP6)and the Bazi Busheng capsule treatment group(SAMP6+BZBS).Ten SAMR1 mice were assigned to a homologous control group(SAMR1).The SAMP6+BZBS group was oral-ly administered Bazi Bushen capsule suspension(2.8 g·kg-1)daily,while the other two groups were orally administered an equal amount of distilled water.After nine weeks of administration,the morphology of the thymus in each group was observed and the thymus in-dex was calculated;HE staining was used to observe the structural changes of thymus tissue;SA-β-gal stai-ning was used to detect thymic aging;flow cytometry was used to detect the proportion of thymic CD3+T cells in each group;Western blot was used to detect the levels of p16,Bax,Bcl-2,and cleaved caspase-3 proteins in thymus;immunofluorescence was applied to detect the proportion of cortical thymic epithelial cells in each group;ELISA was employed to detect IL-7 lev-els in thymus.Results Compared with the SAMP6 group,the thymic index of the SAMP6+BZBS group significantly increased(P＜0.05);the disordered thy-mic structure was significantly improved;the positive proportion of SA-β-gal staining significantly decreased(P＜0.01);the proportion of CD3+T cells apparently increased(P＜0.05);the level of p16 protein signifi-cantly decreased(P＜0.05);the level of Bcl-2 pro-tein significantly increased(P＜0.05),while the lev-el of cleaved caspase-3 protein markedly decreased(P＜0.05);the proportion of cortical thymic epithelial cells evidently increased;the level of IL-7 significantly increased(P＜0.01).Conclusions Bazi Bushen capsule can delay thymic degeneration,inhibit cell ap-optosis in thymus and promote thymic cell development in SAMP6 mice,which may be related to increasing the proportion of cortical thymic epithelial cells and promoting IL-7 secretion.

Objective To study the anti-reflux effect of conical gastric stump embedding in radical resection of esophageal cancer.Methods A total of 60 patients who planned to undergo radical resection of esophageal cancer in our hospital from June 2020 to June 2022 were selected as the study objects,and the patients were divided into the observation group and the control group by random number table method,with 30 cases in each group.Patients in both groups underwent laparoscopic radical resection of esophageal cancer and esophagogastric end-to-side mechanical anastomosis.The observation group adopted the conical gastric stump embedding technique after esophagogastric end-to-side mechanical anastomosis.The perioperative related indexes,postoperative complications and gastroesophageal reflux of patients in the two groups were compared.The postoperative anti-reflux effect was evaluated by reflux disease questionnaire(RDQ)score and 24-hour intraesophageal pH monitoring.Results The operation time and digestive tract reconstruction time of patients in the observation group were longer than those in the control group(P<0.05),while there was no statistically significant difference in the amount of intraoperative bleeding,the number of lymph node dissection,the first exhaust time,or the postoperative hospital stay of patients between the two groups(P>0.05).There was no statistically significant difference in the overall incidence of postoperative complications between the two groups(P>0.05).The severity of postoperative gastroesophageal reflux of patients in the observation group was lighter than that in the control group,and the difference was statistically significant(P<0.05).The RDQ score,24-hour reflux frequency,>5 minutes reflux frequency,pH<4 time,and longest reflux time of patients in the observation group was significantly lower/less/shorter than those in the control group(P<0.05).Conclusion The conical gastric stump embedding technique is safe and feasible in the radical resection of esophageal cancer.Although the operation time and digestive tract reconstruction time are slightly prolonged,it does not increase the perioperative risks,which can significantly reduce the occurrence and severity of postoperative gastroesophageal reflux of patients,and achieve a good anti-reflux effect.

Objective:To analyze the factors affecting overall survival(OS)of adult patients with core-binding factor acute myeloid leukemia(CBF-AML)and establish a prediction model.Methods:A total of 216 newly diagnosed patients with CBF-AML in the First Affiliated Hospital of Zhengzhou University from May 2015 to July 2021 were retrospectively analyzed.The 216 CBF-AML patients were divided into the training and the validation cohort at 7:3 ratio.The Cox regression model was used to analyze the clinical factors affecting OS.Stepwise regression was used to establish the optimal model and the nomogram.Receiver operating characteristic(ROC)curve,calibration curve and decision curve analysis(DCA)were used to evaluate the model performance.Results:Age(≥ 55 years old),peripheral blood blast(≥80％),fusion gene(AML1-ETO),KIT mutations were identified as independent adverse factors for OS.The area under the ROC curve at 3-year was 0.772 and 0.722 in the training cohort and validation cohort,respectively.The predicted value of the calibration curve is in good agreement with the measured value.DCA shows that this model performs better than a single factor.Conclusion:This prediction model is simple and feasible,and can effectively predict the OS of CBF-AML,and provide a basis for treatment decision.

Objective:To explore the application value of simultaneous monitoring of voriconazole(VRCZ)and voriconazole N-oxide(VNO)in efficacy and safety of VRCZ in the prevention and treatment of fungal infections in allogeneic hematopoietic stem cell transplantation(allo-HSCT)patients before engraftment(i.e.,days+1 to+30 after transplantation).Methods:The influencing factors of VRCZ,VNO concentration and MR(CVNO/CVRCz)and the difference of VRCZ in the prevention and treatment of fungal infection and liver and kidney injury were analyzed.The receiver operating characteristic curve(ROC)was used to analyze the differences(the corresponding to the maximum of the Youden index on the curve was set as the cut-off value)to confirm the critical value.Results:The factors affecting VRCZ concentration(CVRCZ),VNO concentration(CVNO)and MR were patient weight,VRCZ daily dose,and transplantation type(all P＜0.05).CVRCZ and CVNO in the effective group were higher than those in the ineffective group(P＜0.001),the opposite of MR(P＜0.001);the liver and renal injury group had lower MR than the normal group(P＜0.05).ROC showed that CVRCZ,CVNO and MR had important value in predicting VRCZ in the prevention and treatment of invasive fungal infections in allo-HSCT patients before engraftment,and their cutoff of concentrations were 0.95 μg/ml,1.35 μg/ml and 1.645,respectively(AUC:0.9677,0.7634,0.9564).CVRCZ and MR can assist in indicating liver[cutoff values:0.65 μg/ml,1.96(AUC:0.5971,0.6663)]and renal injury[cutoff values:0.95 μg/ml,1.705(AUC:0.6039,0.6164)].Conclusion:The great value of simultaneous monitoring of VRCZ,VNO and MR can predict in the efficacy and safety of VRCZ in allo-HSCT patients before engraftment.The prediction accuracy of CVRCZ was higher than that of MR,followed by that of CVNO.Increased CVRCZ and decreased MR increase the risk of liver and kidney injury.

Objective:To explore the overall survival and prognostic factors of patients over 50 years old with acute myeloid leukemia(AML).Methods:The clinical data of 222 AML patients aged over 50 years in our hospital from January 2016 and June 2021 were retrospectively analyzed.Kaplan-Meier method was used to evaluate the overall survival(OS)rate,and Cox regression model to evaluate the prognostic factors.Results:The 1-year and 3-year OS rates of all patients were 46.8％and 28.8％,respectively.The recurrence rate of patients who achieved remission during follow-up time was 57％.Both univariate and multivariate analysis showed that advanced age,MLL family fusion gene,PHF6 gene mutation,TP53 gene mutation,intolerance to standard chemotherapy,incomplete remission,complex karyotype,+mar karyotype and inv(3)karyotype were significantly correlated with prognosis(all P＜0.05).Negative fusion gene and positive AML-ETO fusion gene had no obvious survival advantage in this population.In patients with complete remission,there was no significant survival advantage in those who achieved minimal residual disease negative.Conclusion:AML patients aged over 50 years have a poor outcome and high recurrence rate.The prognosis is affected by multiple factors and has its own characteristics.

Objective:To prepare mesenchymal stem cells with antioxidant capacity (AO-MSC ) from human umbilical cords and evaluate its cell biological properties.Methods:In control group,mesenchymal stem cells (MSC) were isolated by digesting human umbilical cord Wharton's Jelly tissues with 0.2％ collagenase Ⅱ,and the released cells were collected and cultured in an animal serum-free culture medium.In AO-MSC group,incompletely collagenase Ⅱ-digested tissue debris were allowed to adhere to flusk flat bottoms and the AO-MSC was harvested by adherent culture. The conventional digestion and culture method was used as control.MSC colony forming ability was evaluated by fibroblast colony forming assay (CFU-F).MSC proliferative capacity was evaluated by CCK-8 assay.The MSC surface markers were detected by using flow cytometry and immunofluorescence staining.The adipogenic and osteogenic capacity of MSC was evaluated by multi-differentiation in vitro,and the mRNA expression of genes that control adipogenic and osteogenic differentiation was detected by real-time fluorescence quantitative PCR (RT-qPCR );Moreover,the mRNA expression of antioxidant substances such as SOD-1,GSH,GAT,and NQO1 in MSC was also evaluated by RT-qPCR.Results:The AO-MSC isolated by this strategy reached a confluence of 80％-90％ at around 18 days and grew in a swirling pattern.Flow cytometry and immunofluorescence staining assays showed that CD73,CD29,CD105,CD90 were highly expressed and CD31,CD45,HLA-DR were scarcely expressed in AO-MSC.AO-MSC exhibited stronger self-renewal and differentiation ability compared to MSC.However,the in vitro adipogenic-osteogenic capacity of MSC in the control group was stronger than that of AO-MSC.RT-qPCR assay showed that AO-MSC expressed higher mRNA levels of antioxidant substances compared to MSC.Conclusion:Human AO-MSC is successfully prepared from human umbilical cord without animal serum.

Gossypol is a natural product extracted from cotton seeds,roots and stems,once used as a male contraceptive and lat-er found with an anti-tumor effect.Recent studies show that it has an antiviral effect after structurally modified.This review focuses on the status quo of present studies on the effects of gossypol and its derivatives in anti-reproduction and anti-PCa,with an introduction of the application of the new compounds obtained from structural modification of gossypol in the treatment of PCa.

Objective:To preliminarily investigate the applicability of a poliovirus pseudovirus-based neutralization assay in evaluating the immunogenicity of recombinant poliovirus vaccines and their in vivo potency in rats. Methods:Serum samples from rats immunized with recombinant poliovirus vaccines were tested using both the pseudovirus neutralization assay and the live-virus neutralization assay with Sabin strain. The consistency and correlation of the two methods were analyzed using the Kappa test and Spearman′s rank correlation.Results:For the neutralizing antibodies against typeⅠ, Ⅱ, and Ⅲ polioviruses, the Kappa values for consistency analysis of the two methods were 0.914, 1.000, and 0.751, respectively ( P<0.001), and the correlation coefficients ( R values) were 0.833, 0.927, and 0.859, respectively ( P<0.001). Conclusions:The test results of the two methods are consistent and show a good correlation, indicating that the pseudovirus neutralization assay can be applied to evaluating the immunogenicity of poliovirus vaccines and also can be used in rat potency tests.