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.

Humans ; Vascular Stiffness ; Coal Mining ; Occupational Diseases/epidemiology* ; Risk Factors ; Coal ; Miners

In this study, fluvoxamine maleate sustained-release pellet system tablets were prepared and were used to evaluate their release behaviors in vitro. Fluvoxamine maleate pellets were prepared using centrifugal-spherization method and coated by fluidized bed as bottom-spray. The multi-unit sustained-release pellets and appropriate excipients for prescription volumes were mixed uniformly and then compressed to tablets. Screening and determining the optimal formulation of drug loaded pellets through L8 (2⁴) Taguchi experiment. Using Minitab software to design a DOE experiment with 2⁴ partial factors, including material temperature, fan speed, atomization pressure, and spray rate to optimize the bottom spray coating process. Taking monostearate glycerol ester with a particle size of 24-40 mesh as the main diluent for tableting to relieve the delamination phenomenon between pellets and excipients during tablet pressing and reduce mechanical damage to the coating film. By examining the powder fluidity indexes such as angle of repose, bulk density, tapped density, and Hausner ratio of mixed particles, it was found that the flowability and compressibility are good and suitable for direct compression. Evaluate the basic properties of the sustained-release tablets, investigate the in vitro release behavior and study the release mechanism. The results of in vitro release test showed that the self-made sustained-release tablets could disintegrate into independent pellet units in phosphate buffer at pH 6.8 and release slowly within 24 h, which conformed to the first-order drug release model. The fluvoxamine maleate sustained-release pellet system tablets meet the requirements of preparation design and has a great commercial prospect.

Objective To study the pharmacokinetic characteristics of etoricoxib tablets in healthy Chinese subjects and to evaluate the bioequivalence and safety of the test and reference formulations.Methods In a randomised,single-dose,two-period,two-sequence crossover trial,28 healthy subjects were enrolled under the fasting and fed conditions,respectively,who received a single oral dose of 60 mg of etoricoxib tablets in the test or reference formulation.The concentration of etoricoxib in plasma was detected by LC-MS/MS,and the main pharmacokinetic parameters were calculated to evaluate bioequivalence and using WinNonlin 8.2 software.Results The main pharmacokinetic parameters of the test and reference preparations were as follows:The fasting condition Cmax of etoricoxib were(1 176.96±287.95)and(1 164.93±189.65)ng·mL-1;AUC0-t were(18 651.95±6 100.27)and(19 241.39±6 107.48)ng·h·mL-1;and AUC0-∞ were(19 939.15±7 553.27)and(20 536.31±7 223.40)ng·h·mL-1.The fed condition Cmax of etoricoxib were(913.50±184.72)and(878.59±164.35)ng·mL-1;and AUC0-t were(19 085.22±5 155.01)and(18 669.54±4 508.21)ng·h·mL-1;AUC0-∞ were(20 103.77±5 567.02)and(19 528.05±4 989.74)ng·h·mL-1.The 90％confidence intervals for the geometric mean ratios of the main pharmacokinetic parameters in the fasting and fed conditions fell between 80.00％and 125.00％.The incidence of adverse events in the fasting and fed conditions were 28.57％and 21.43％,respectively.Conclusion Two kinds of etoricoxib tablets are bioequivalent,and have similar safety in healthy Chinese subjects.

The compound (E)-1-(4-(3-(5-chloro-6-oxo-3,6-dihydropyridin-1(2H)-yl)-3-oxo-propyl-1-ene-1-yl) phenyl)-3-(4-fluorophenyl) urea (C12), a novel derivative of piperlongumine previously synthesized by our research group, was investigated in this study to examine its effects on human non-small cell lung cancer cell line H1299 in vitro and elucidate its potential mechanism of action. The impact of C12 on the proliferation, migration, and invasion abilities of H1299 cells were assessed using methyl thiazolyl tetrazolium (MTT) assay, wound healing assay, cloning formation assay, and Transwell assay. Flow cytometry was employed to evaluate the influence of C12 on cell cycle progression, reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), and apoptosis induction in H1299 cells. Western blot analysis was conducted to investigate the expression levels of p21, Cyclin B1, CDK1, Bax, Bcl-2, JNK, p-JNK, Erk1/2, p-Erk1/2, p38 and p-p38 proteins for exploring the anti-tumor mechanism underlying C12's actions. The results demonstrated that C12 exerted inhibitory effects on the proliferation, migration, and invasion capacities of H1299 cells in a time-dependent and concentration-dependent manner. Moreover, C12 induced G2/M phase arrest in the cell cycle, reduced MMP levels, elevated ROS production, and triggered apoptotic processes. Flow cytometry analysis revealed that C12 downregulated Cyclin B1 and CDK1 protein expressions, resulting in G2/M phase arrest. C12 also upregulated Bax/Bcl-2 ratio, promoting apoptosis. Furthermore, C12 activated MAPK signaling pathway by enhancing phosphorylation levels of JNK, Erk1/2, and p38 proteins. In conclusion, C12 significantly suppressed proliferation, migration, and invasion capabilities while inducing cell cycle arrest and apoptosis in H1299 cells. These effects may be attributed to activation of the MAPK signaling pathway.

Patients with severe trauma require an extremely timely treatment and transfusion plays an irreplaceable role in the emergency treatment of such patients. An increasing number of evidence-based medicinal evidences and clinical practices suggest that patients with severe traumatic bleeding benefit from early transfusion of low-titer group O whole blood or hemostatic resuscitation with red blood cells, plasma and platelet of a balanced ratio. However, the current domestic mode of blood supply cannot fully meet the requirements of timely and effective blood transfusion for emergency treatment of patients with severe trauma in clinical practice. In order to solve the key problems in blood supply and blood transfusion strategies for emergency treatment of severe trauma, Branch of Clinical Transfusion Medicine of Chinese Medical Association, Group for Trauma Emergency Care and Multiple Injuries of Trauma Branch of Chinese Medical Association, Young Scholar Group of Disaster Medicine Branch of Chinese Medical Association organized domestic experts of blood transfusion medicine and trauma treatment to jointly formulate Chinese expert consensus on blood support mode and blood transfusion strategies for emergency treatment of severe trauma patients ( version 2024). Based on the evidence-based medical evidence and Delphi method of expert consultation and voting, 10 recommendations were put forward from two aspects of blood support mode and transfusion strategies, aiming to provide a reference for transfusion resuscitation in the emergency treatment of severe trauma and further improve the success rate of treatment of patients with severe trauma.

Bone organoids can simulate the complex structure and function of the bone tissues, which makes them a frontier technology in organoid researches. Bone organoids show a tremendous potential of applications in bone disease modeling, bone injury repair, and medicine screening. Although advancements have been made so far in constructing bone organoids with functional structures like mineralization, bone marrow, trabecular bone, callus, woven bone, etc, the researches in this field are confronted with numerous challenges such as lack of standardized construction strategies and unified evaluation criteria, which limits their further promotion and application. To standardize researches in bone organoids, the Orthopedic Expert Committee of Geriatric Branch of Chinese Association of Gerontology and Geriatrics, the Youth Osteoporosis Group of Orthopedic Branch of Chinese Medical Association, the Osteoporosis Group of Orthopedic Surgeon Branch of Chinese Medical Doctor Association, and the Osteoporosis Committee of Shanghai Association of Integrated Traditional Chinese and Western Medicine organized related experts to formulate Expert consensus on the construction, evaluation, and application of bone organoids ( version 2024) based on an evidence-based approach. A total of 17 recommendations were put forth, aiming to standardize researches and clinical applications of bone organoids and enhance their value in scientific research and clinical practice.

AIM To investigate the effects of Moluodan Dami Pills on chronic atrophic gastritis(CAG)rats and their mechanism.METHODS The rat models were randomly divided into the model group,the low-dose group and high-dose Moluodan Dami Pills groups(2.43 g/kg and 4.86 g/kg),and vitamin A group(0.32 g/kg),following the 16 weeks successful induction of CAG by five-factor modeling method,in contrast to another 10 normal rats of the control group.After 8 weeks corresponding administration,the rats of each group had their general physiological status and pH value of gastric juice assessed;their pathological changes of gastric mucosa observed by naked eyes combined with HE staining;their changes of gastrin-secreting cells(G cells)and somatostatin-secreting cells(D cells)in gastric mucosa observed by immunohistochemistry;and their serum levels of pepsinogen Ⅰ/pepsinogen Ⅱ(PG Ⅰ/PG Ⅱ)ratio,TNF-α and IL-6 detected by ELISA.RESULTS Compared with the model group,the groups intervened with Moluodan Damei Pills and vitamin A displayed lower pH values of gastric juice(P＜0.05),improved pathological changes of gastric mucosa,increased G and D cells counts(P＜0.05,P＜0.01),increased ratio of serum PGⅠ/PGⅡ,and decreased levels of IL-6 and TNF-α(P＜0.05,P＜0.01).CONCLUSION Moluodan Dami Pills can effectively improve the symptoms of CAG rats through its influence on the number and secretion abilityof G and D cells,the levels of serum PG Ⅰ/PG Ⅱ ratio and inflammatory factors.

Background and purpose:It is still a great challenge to clarify the signal molecules that mediate the communication between cancer-associated fibroblasts(CAFs)and tumor cells.These signal molecules are very important for cancer metastasis.The purpose of this study was to explore the communication mechanism of pleckstrin-2/miR-196a signal axis mediated by lung cancer cells in tumor microenvironment.Methods:Human lung adenocarcinoma cell line H1299 and human embryonic lung cell MRC-5 were selected as the research objects.H1299 cells were transfected with lentivirus(PLEK2)expressing PLEK2 and Vector control,and exosomes(Vector_exo,PLEK2_exo)were isolated after 24 h of transfection.MRC-5 cells were transfected with miR-196a mimetic or inhibitor.The expressions of PLEK2 and epithelial-mesenchymal transition(EMT)-related proteins were analyzed by Western blot.The expression of miR-196a was analyzed by polymerase chain reaction(PCR),and the metastasis and invasion ability of cells were determined by transwell assay.Six female BALB/c-nu mice were randomly divided into Vector group and PLEK2 group,with 3 mice in each group.Mice in each group were injected with H1299 cells transfected with Vector or PLEK2 through the tail vein.After 4 weeks,lung tissue was taken out for H-E staining and immunohistochemical staining to analyze the expression of α-smooth muscle actin(α-SMA).All animal experiments were approved by the ethics committee of First Hospital of Changsha City(Changsha Hospital,Xiangya School of Medicine,Central South University)(ethics number:EI-2021-103).Results:Compared with the Vector group,the number of pulmonary metastatic nodules and the expression of α-SMA in metastatic cancer in PLEK2 group increased significantly(P＜0.001).Compared with Vector group,the expression level of miR-196a in H1229 cells in PLEK2 group increased significantly(P＜0.05),and the expression level of miR-196a was significantly higher in PLEK2_exo than in Vector_exo(P＜0.05).Compared with Vector_exo group,the expression levels of miR-196a,α-SMA and fibroblast activation protein(FAP)in MRC-5 cells in PLEK2_exo group increased significantly(P＜0.05).Compared with the negative control(NC),the expression levels of α-SMA and FAP in MRC-5 cells transfected with miR-196a increased significantly(P＜0.05).On the contrary,by transfection with miR-196a inhibitors(si-miR-196a#1 and si-miR-196a#),the expression levels of α-SMA and FAP were significantly inhibited(P＜0.05).Compared with NC-CM group,the number of metastatic cells,invasive cells and the expression of vimentin in miR-196a-CM group increased significantly(P＜0.001),and the expression of E-cadherin decreased significantly(P＜0.001).In addition,compared with Vector_exo-CM group,PLEK2_exo-CM group had significant increase in number of metastatic and invasive cells and the expression of vimentin(P＜0.01),and significant decrease in the expression of E-cadherin(P＜0.001).Conclusion:Upregulation of PLEK2 can enhance the level of exosomes miR-196a derived from lung cancer cells,thereby promoting the activation of CAFs.The activated CAFs can further enhance the invasive ability of lung cancer cells.

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]