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.

AIM: To compare the efficacy of different intraocular lens(IOL)fixation in aphakic patients lacking capsule support.METHODS:Retrospective study. Totally 120 cases(120 eyes)of aphakia patients who lacked capsule support admitted to our hospital from June 2019 to June 2024 were selected as the study subjects and randomly assigned into group A and group B, with 60 cases in each group. Group A underwent subcapsular IOL deep scleral fixation, while group B underwent IOL suture suspension fixation in the ciliary groove. The surgery time, uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), intraocular pressure(IOP), corneal endothelial cell density(CECD), corneal endothelial cell loss rate, and postoperative complications were compared between the two groups before and at 1, 3, 6 mo after surgery.RESULTS:The operation time of the group A was lower than that of the group B(24.69±2.69 vs. 32.75±3.75 min, t=11.937, P<0.05). The UCVA and BCVA in both groups were better than those before operation, and the group A was better than the group B(all P<0.05). The loss rates of corneal endothelial cells in the group A were lower than those in the group B at 1, 3 and 6 mo after surgery, the IOP in the group A was lower than that in the group B at 1 mo after surgery, and the CECD in the group A was higher than the group B(all P<0.05). The 3 eyes(5.0%)of the postoperative IOL ectopic in the group A were less than 11 eyes in the group B(18.3%, P=0.023).CONCLUSION:Subcapsular IOL deep scleral fixation has prominent curative effects on aphakic patients who lack capsule support. It helps improve vision, with less operation time, and fewer postoperative complications.

Ureaplasma urealyticum (UU) is one of the most commonly occurring pathogens associated with genital tract infections in infertile males, but the impact of seminal UU infection in semen on intrauterine insemination (IUI) outcomes is poorly understood. We collected data from 245 infertile couples who underwent IUI at The First Affiliated Hospital of USTC (Hefei, China) between January 2021 and January 2023. The subjects were classified into two groups according to their UU infection status: the UU-positive group and the UU-negative group. We compared semen parameters, pregnancy outcomes, and neonatal birth outcomes to investigate the impact of UU infection on IUI outcomes. There were no significantly statistical differences in various semen parameters, including semen volume, sperm concentration, total and progressive motility, sperm morphology, leukocyte count, the presence of anti-sperm antibody, and sperm DNA fragmentation index (DFI), between the UU-positive and UU-negative groups of male infertile patients (all P > 0.05). However, the high DNA stainability (HDS) status of sperm differed between the UU-positive and UU-negative groups, suggesting that seminal UU infection may affect sperm nuclear maturation ( P = 0.04). Additionally, there were no significant differences in pregnancy or neonatal birth outcomes between the two groups (all P > 0.05). These results suggest that IUI remains a viable and cost-effective option for infertile couples with UU infection who are facing infertility issues.
Humans ; Male ; Ureaplasma Infections/complications* ; Female ; Infertility, Male/therapy* ; Ureaplasma urealyticum/isolation & purification* ; Pregnancy ; Adult ; Pregnancy Outcome ; Semen Analysis ; Insemination, Artificial ; Semen/microbiology* ; China

OBJECTIVE: To comprehensively evaluate the effect of icariin in alleviating reproductive function damage (RFD) in male mice via in vitro and in vivo experiments. METHODS: We isolated Leydig cells from 60 KM male mice in vitro, and examined the toxic effect of icariin on the Leydig cells using Cell Counting Kit-8 (CCK-8). We equally randomized the mice into six groups: normal control, RFD model control (made by intraperitoneal injection of busulfan at 10 mg/kg combined with cyclophosphamide (CP) at 120 mg/kg), positive control, and low-, medium- and high-dose icariin. After modeling, we treated the mice in the positive control group with Wuziyanzong Pills and those in the low-, medium- and high-dose icariin groups by intragastrical administration of icariin at 20, 40 and 80 mg/kg-1, respectively, for 30 successive days. Then we obtained the weight and visceral coefficients of the reproductive organs, calculated the sperm count, observed the pathological changes in the testis tissue by HE staining, measured the serum testosterone (T) level by ELISA, determined the indexes of testicular oxidative stress and nitric oxide (NO) signaling pathway by colorimetric assay, and detected the expression levels of the pro-apoptotic genes Fas and Bax by qRT-PCR. RESULTS: CCK-8 assay confirmed that icariin had no toxic effect on the isolated Leydig cells of the mice, and could effectively reduce busulfan- and CP-induced cytotoxicity and promote the secretion of serum T. Icariin at 80 mg/kg significantly increased the visceral coefficient of the testis and promoted spermatogenesis (P<0.05), but had little effect on the visceral coefficient of the epididymis in the RFD model mice. Testicular histomorphometric observation revealed significantly improved testis structure, intact boundary membrane of seminiferous tubules and increased numbers of various types of spermatogenic cells of the model mice after treated with icariin. Compared with the mice in the model control group, those treated with high-dose icariin showed a significantly reduced content of malondialdehyde (MDA) (by 35.3%, P<0.01), elevated total antioxidant capacity (TAOC) and superoxide dismutase (T-SOD) activity (P<0.05), and decreased NO content and nitric oxide synthase (NOS) activity in the testis tissue (P<0.01). In addition, icariin exhibited an evident inhibitory effect on the expressions of the pro-apoptotic genes Bax and Fas. CONCLUSION Icariin can ameliorate oxidative stress-induced damage to the testicular function and protect spermatogenesis of male mice by elevating TAOC, decreasing NOS activity, inhibiting the NO level in the testis, and suppressing busulfan- and CP-induced apoptosis of testicular cells.
Animals ; Male ; Cyclophosphamide/adverse effects* ; Mice ; Busulfan/adverse effects* ; Flavonoids/pharmacology* ; Leydig Cells/drug effects* ; Oxidative Stress/drug effects* ; Testis/drug effects* ; Apoptosis/drug effects* ; Testosterone/blood*

Objective To identify the potential categories and influencing factors of apathy in stroke patients,providing a basis for precise typing and individualized interventions by healthcare professionals.Methods Using the convenience sampling method,stroke patients from 2 tertiary hospitals in Xinjiang Uggur Automous Region were selected from November 2023 to August 2024,and were surveyed using the General Information Questionnaire,Apathy Evaluation Scale-Informant,Perceived Autonomy Scale,and Stroke Self-Efficacy Questionnaire.The latent profile analysis was used to identify potential categories of apathy,and logistic regression analysis was used to explore the differences in the characteristics of patients in different categories.Results The apathy symptoms of 521 stroke patients could be divided into 3 potential categories:mild apathy group(23.6％),moderate apathy-low interest-low behavioral group(46.5％),and heavy apathy-low interest-low cognitive group(29.9％).Logistic regression showed that age 45～＜60 years,duration of the disease＜6 months,and high rehabilitation self-efficacy were the common protective factors of the moderate apathy-low interest-low behavioral group and the heavy apathy-low interest-low cognitive group.The dependence on activities of daily living was a risk factor for the moderate apathy-low interest-low behavioral group,and high perception of autonomy was a protective factor for the heavy apathy-low interest-low cognitive group.Conclusion Apathy symptoms in stroke patients are characterized by distinct categories,which are influenced by age,stroke duration,ADL,rehabilitation self-efficacy,and perception of autonomy.Healthcare professionals should adopt effective strategies to precisely intervene based on different potential categories of protective factors and risk factors to alleviate their apathy.

Objective:To conduct an occupational hygiene investigation and simulated sampling and testing on welding positions in a company in a certain province, and to perform a simulated analysis of the concentration of occupational hazard factors in workers suspected of occupational asthma.Methods:In November 2023, the investigation and analysis of workers' exposure to occupational hazard factors were carried out through occupational hygiene surveys, laboratory simulated sampling and testing, and a combination of qualitative and quantitative detection methods.Results:Toluene diisocyanate (TDI) was present in the workplace air of the employer. TDI was detected in the raw materials provided by the workers. Laboratory simulations of the production process and working conditions at the position were conducted with sampling at different distances, revealing a maximum TDI concentration of 0.49 mg/m 3 and a minimum concentration of 0.01 mg/m 3. The results showed that the closer the sampling distance was to the breathing zone, the more significantly the TDI concentration increased. The laboratory simulated sampling and testing results were highly consistent with the on-site sampling and testing results from a testing agency in Beijing. Conclusion:The occupational hazard factor TDI is present in the workers' workplace, and TDI may be the cause of the suspected occupational asthma in the workers.

Objective To investigate the stability and reproducibility of the treatment fractions during the intensity-modulated radiotherapy(IMRT)for breast cancer and the effect of respiratory motion on the dose irradiation of breast cancer radiotherapy by comparing the results of breast cancer dosimetric verification based on fractionated images by an electronic portal imaging device(EPID).Methods A total of 28 IMRT patients admitted to some hospital from January to June 2023 were grouped according to the pathological results and effects of respiratory motion on the accuracy of radiotherapy during clinical treatment,including 14 cases in a breast group and 14 cases in a non-breast group with 8 ones of head and neck tumors,5 ones of esophageal cancer and 1 case of cervical cancer.All the patients underwent a scan with cone beam computed tomography(CBCT)before the first radiotherapy,and image registration was carried out with a positioning CT.An EPID was used to acquire transmission dose images of 10 fractions of radiotherapy,and γ analysis was performed using the RIT 113 QA software to compare the images of the subsequent 9 fractions with those of the first fraction,with the images of the first fraction of radiotherapy as the baseline values.Absolute maximum dose normalization was implemented under the condition of 10％dose assessment threshold,and the γ-pass rates under the 3 criteria of 2％/2 mm,3％/2 mm and 3％/3 mm were counted separately.The fraction dose verification results of the 28 patients were divided into 3 treatment phases of 2-4 times(T1),5-7 times(T2)and 8-10 times(T3)to analyze the stability of dose irradiation during the radiotherapy.SPSS 22.0 software was used for statistical analysis.Results Under the condition of 10％dose assessment threshold,the breast and non-breast groups had the γ-pass rates being(95.80±2.65)％and(94.60±6.59)％under the 2％/2 mm criterion and(98.46±1.31)％and(97.50±3.30)％under the 3％/2 mm criterion respectively,and the differences were statistically significant(all P<0.05).Under the assessment criteria of 2％/2 mm,3％/2 mm and 3％/3 mm,the breast group had the γ-pass rates of fractions of treatment significantly lower than those of the non-breast group(all P<0.05),while the γ-pass rates showed no significant differences at T1,T2 and T3 treatment phases(all P>0.05).Conclusion EPID fraction images contribute to evaluating IMRT accuracy effectively.IMRT has high stability and reproducibility during the treatment cycle,while respiration may result in dose deviation during the fraction radiotherapy for breast cancer,and optical surface tracking technology or active breathing control technology is suggested to be involved in to relieve dose deviation.[Chinese Medical Equipment Journal,2025,46(6):54-58]

AIM To investigate the effects of Rutong Ruanjian Tablets on angiogenesis in cancer tissues of rats with preneoplastic breast cancer(PBC).METHODS 60 female SD rats were randomly divided into a blank group of 10 rats and a model group of 50 rats for the establishment of the PBC models of Liver-Qi Stagnation and Blood Stasis Pattern with 9 weeks of oral administration of 7,12-dimethylbenz[a]anthracene(DMBA)and cervical ligation.After successful modeling,the rats were randomly divided into the model group,the tamoxifen group(3.2 mg/kg),the Rutong Ruanjian Tablets group(128 mg/kg),the 3,5-difluorobenzoyl group(DAPT,5 mg/kg),and the Rutong Ruanjian Tablets(128 mg/kg via gavage)+DAPT(5 mg/kg intraperitoneal injection)group,for 1 month corresponding drug administration,with 10 rats in each group.Then the rats had their cancer progression and syndrome scores observed;their angiogenesis evaluated by assessment of microvascular density(MVD);their vascular endothelial growth factor(VEGF)expression assessed by immunohistochemistry;and their mRNA and protein expressions of proteins related to the DLL4/Notch1/Hes1 pathway measured using RT-qPCR,immunohistochemistry and Western blot.RESULTS During carcinogenesis of rats induced by DMBA,there was gradual disappearance of E-cadherin expression and consistency of HE staining result with the PBC progression confirming the success of the modeling.Compared with the blank group,the model group showed increased MVD values,mRNA expression of Notch1 and Hes1,and protein expressions of VEGF,DLL4,Notch1 and Hes1(P＜0.05,P＜0.01).Compared with the model group,the Rutong Ruanjian Tablets group exhibited reduced MVD values,mRNA expression of Notch1 and Hes1,and protein expressions of VEGF,DLL4,Notch1 and Hes1(P＜0.05,P＜0.01).The Rutong Ruanjian Tablets+DAPT group showed reduced mRNA expression of Notch1 and Hes1,and protein expressions of DLL4,Notch1 and Hes1 compared to the Rutong Ruanjian Tablets group(P＜0.05,P＜0.01).CONCLUSION Rutong Ruanjian Tablets can inhibit angiogenesis and attenuate cancer progression in PBC rats of Liver-Qi Stagnation and Blood Stasis Pattern,and the mechanism may lie in the downregulation of DLL4/Notch1/Hes1 signaling pathway related proteins.