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.

Objective:To explore the role of NK cells in allogeneic hematopoietic stem cell micro-transplantation(MST)in the treatment of patients with acute myeloid leukemia(AML).Methods:Data from 93 AML patients treated with MST at our center from 2013-2018 were retrospectively analyzed.The induction regimen was anthracycline and cytarabine combined with peripheral blood stem cells transplantation mobilization by granulocyte colony stimulating factor(GPBSC),followed by 2-4 courses of intensive treatment with medium to high doses of cytarabine combined with GPBSC after achieving complete remission(CR).The therapeutic effects of one and two courses of MST induction therapy on 42 patients who did not reach CR before transplantation were evaluated.Cox proportional hazards regression analysis was used to analyze the impact of donor NK cell dose and KIR genotype,including KIR ligand mismatch,2DS1,haplotype,and HLA-Cw ligands on survival prognosis of patients.Results:Forty-two patients received MST induction therapy,and the CR rate was 57.1％after 1 course and 73.7％after 2 courses.Multivariate analysis showed that,medium and high doses of NK cells was significantly associated with improved disease-free survival(DFS)of patients(HR=0.27,P=0.005;HR=0.21,P=0.001),and high doses of NK cells was significantly associated with improved overall survival(OS)of patients(HR=0.15,P=0.000).Donor 2DS1 positive significantly increases OS of patients(HR=0.25,P=0.011).For high-risk patients under 60 years old,patients of the donor-recipient KIR ligand mismatch group had longer DFS compared to the nonmismatch group(P=0.036);donor 2DS1 positive significantly prolonged OS of patients(P=0.009).Conclusion:NK cell dose,KIR ligand mismatch and 2DS1 influence the therapeutic effect of MST,improve the survival of AML patients.

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]

The patient,a male newborn,was admitted to the hospital 2 hours after birth due to prematurity(gestational age 27+5 weeks)and respiratory distress occurring 2 hours postnatally.After admission,the infant developed fever and elevated C-reactive protein levels.On the fourth day after birth,metagenomic next-generation sequencing of cerebrospinal fluid indicated a positive result for Mycoplasma hominis(9 898 reads).On the eighth day,a retest of cerebrospinal fluid metagenomics confirmed Mycoplasma hominis(56 806 reads).The diagnosis of purulent meningitis caused by Mycoplasma hominis was established,and the antibiotic treatment was switched to moxifloxacin[5 mg/(kg·day)]administered intravenously for a total of 4 weeks.After treatment,the patient's cerebrospinal fluid tests returned to normal,and he was discharged as cured on the 76th day after birth.This article focuses on the diagnosis and treatment of neonatal Mycoplasma hominis purulent meningitis,introducing the multidisciplinary diagnosis and treatment of the condition in extremely preterm infants.[Chinese Journal of Contemporary Pediatrics,2024,26(4):432-436]

Objective To investigate the efficacy and safety of nusinersen sodium in the treatment of children with spinal muscular atrophy(SMA).Methods A retrospective analysis was conducted on the clinical data of 50 children with 5q SMA who received nusinersen sodium treatment and multidisciplinary treatment management in Shanxi Children's Hospital from February 2022 to February 2024.Results Compared with the baseline data,67%(8/12),74%(35/47),and 74%(35/47)of the SMA children had a clinically significant improvement in the scores of Philadelphia Infant Test of Neuromuscular Disorders,Hammersmith Functional Motor Scale Expanded,and Revised Upper Limb Module,respectively,and the distance of 6-minute walking test increased from 207.00(179.00,281.50)meters to 233.00(205.25,287.50)meters(P<0.05)after nusinersen sodium treatment.Of all 50 children with SMA,24(48%)showed good tolerability after administration,with no significant or persistent abnormalities observed in 2 034 laboratory test results,and furthermore,there were no serious or immunological adverse events related to the treatment.After treatment,there was a significant change in forced vital capacity as a percentage of the predicted value in 27 children with restrictive ventilatory dysfunction,as well as a significant change in the level of 25-(OH)vitamin D in 15 children with vitamin D deficiency(P<0.05).Conclusions For children with SMA,treatment with nusinersen sodium can continuously improve the response rates of motor function scales,with good tolerability and safety.

Objective To investigate the efficacy and safety of exchange transfusion in neonates with severe pertussis. Methods A retrospective analysis was performed for the medical data of five neonates with severe pertussis who underwent exchange transfusion in the Department of Neonatology,Hunan Children's Hospital,from August 2019 to March 2024. The clinical characteristics of the patients were summarized,and the efficacy and adverse reactions of exchange transfusion were analyzed. Results All five neonates had the symptoms of hypoxemia,recurrent apnea,and heart failure and required invasive mechanical ventilation. Two cases of pulmonary hypertension were observed,one of which was complicated by decompensated shock. Before exchange transfusion,the five children had a median leukocyte count of 82.60×109/L,a median absolute lymphocyte count of 28.20×109/L,and a median absolute neutrophil count of 43.10×109/L,and reexamination at 4 hours after exchange transfusion showed that these values decreased to 28.40×109/L,7.60×109/L,and 15.40×109/L,respectively. The four children who underwent exchange transfusion in the early stage of cardiopulmonary failure showed varying degrees of improvement in oxygenation and a reduction in the partial pressure of carbon dioxide,and they were discharged after improvement;the one child who underwent exchange transfusion in the late stage of cardiopulmonary failure ultimately died. No child experienced severe adverse reactions related to exchange transfusion. Conclusions For neonates with severe pertussis,initiating exchange transfusion in the early stages of cardiopulmonary failure can effectively reduce leukocyte levels,potentially improve survival rates,and is relatively safe.

Hip fracture in the elderly is characterized by high incidence, high disability rate, and high mortality and has been recognized as a public health issue threatening their health. Surgery is the preferred choice for the treatment of elderly patients with hip fracture. However, lower extremity deep venous thrombosis (DVT) has an extremely high incidence rate during the perioperative period, and may significantly increase the risk of patients′ death once it progresses to pulmonary embolism. In response to this issue, the clinical guidelines and expert consensuses all emphasize active application of comprehensive preventive measures, including basic prevention, physical prevention, and pharmacological prevention. In this prevention system, basic prevention is the basis of physical and pharmacological prevention. However,there is a lack of unified and definite recommendations for basic preventive measures in clinical practice. To this end, the Orthopedic Nursing Professional Committee of the Chinese Nursing Association and Nursing Department of the Orthopedic Branch of the China International Exchange and Promotive Association for Medical and Health Care organized relevant nursing experts to formulate Expert consensus on perioperative basic prevention for lower extremity deep venous thrombosis in elderly patients with hip fracture ( version 2024) . A total of 10 recommendations were proposed, aiming to standardize the basic preventive measures for lower extremity DVT in elderly patients with hip fractures during the perioperative period and promote their subsequent rehabilitation.

Objective To study the effect of drinking carbohydrate drinks before cesarean section on mothers and neonates,and to explore the application value of drinking carbohydrate drinks before cesarean section.Methods The clinical data of 206 singleton women who underwent selective cesarean section in Obstetrics and Gynecology Hospital,Fudan University from Jun 2020 to Jun 2021 were retrospectively studied.Patients were divided into enhanced recovery after delivery(ERAD)group and control group according to whether drinking carbohydrate drinks before cesarean section.A retrospective cohort study was conducted to analyze the effect of preoperative carb drinks on preoperative fluid supplementation,postoperative rehabilitation and neonatal prognosis.Results Among patients who fasted for less than 12 hours,the ERAD group had a lower fluid supplementation rate and a smaller average fluid supplementation volume compared to the control group(P＜0.05).The ERAD group had a lower rate of prokinetic agent using after surgery(P＜0.05).Among women without a history of abdominal surgery,the ERAD group had less blood loss 24 hours after surgery(P＜0.05).There were no significant differences in postoperative fever rate,incidence of nausea and vomiting,time of first flatus,neonatal apgar score,exit observation room neonatal blood,and neonatal neonatal intensive care unit(NICU)admission rate between the two groups.Among newborns with high-risk factors for hypoglycemia,the ERAD group had lower enter observation room neonatal blood compared to the control group,and a higher incidence of hypoglycemia(P＜0.05).Conclusion Oral intake of carbohydrate drinks before cesarean section may be beneficial in reducing fluid supplementation before elective cesarean section,promoting postoperative gastrointestinal function recovery,and reducing postoperative bleeding.However,it may be related to the occurrence of neonatal hypoglycemia.

Four pyrazines were isolated from the n-butanol fraction of Hypecoum erectum L. by using various chromatographic methods, including MCI gel, ODS, silica gel and semi-preparative HPLC. The structures of the isolated compounds were identified as hyperectpyrazin A (1), 1′S-(6-methylpyrazin-2-yl)-ethane-1′,2′-diol (2), 2-hydroxymethyl-6-methylpyrazin (3) and pyrazine-2-carboxylic acid (4) by spectroscopy methods (1D NMR, 2D NMR, UV, IR, MS, etc.). The absolute configuration of compound 2 was determined by using the Mo₂(OAc)₄ induced CD analysis for the first time. Compound 1 was a new compound, compounds 2-4 were isolated from H. erectum for the first time. Compounds 1-4 were evaluated for their inhibition against acetylcholinesterase and nitric oxide generation induced by lipopolysaccharide-RAW264.7 macrophage cells. At a concentration of 50 μmol·L^-1, compounds 2 and 4 displayed inhibitory effects on acetylcholinesterase with the inhibition rates of 44.40% and 43.99%, respectively.

Objective To evaluate the effects of high-fat diet on the pharmacokinetics of metronidazole in Chinese healthy adult subjects.Methods This program is designed according to a single-center,randomized,open,single-dose trial.Forty-seven healthy subjects were assigned to receive single dose of metronidazole tablets 200 mg in either fasting and high-fat diet state,and blood samples were taken at different time points,respectively.The concentrations of metronidazole in plasma were determined by high performance liquid chromatography-mass spectromentry.Results The main pharmacokinetic parameters of metronidazole in fasting state and high-fat diet state were as follows:Cmax were(4 799.13±1 195.32)and(4 044.17±773.98)ng·mL-1;tmax were 1.00 and 2.25 h;t1/2 were(9.11±1.73)and(9.37±1.79)h;AUC0_t were(5.59±1.19)x 104 and(5.51±1.18)x 104 ng·mL-1·h;AUC0_∞ were(5.79±1.33)x 104 and(5.74±1.32)× 104 ng·mL-1·h.Compared to the fasting state,the tmaxof the drug taken after a high fat diet was delayed by 1.25 h(P＜0.01),Cmax,AUC0_t,AUC0-∞ were less or decreased in different degrees,but the effects were small(all P＞0.05).Conclusion High-fat diet has little effects on the pharmacokinetic parameters of metronidazole,which does not significantly change the degree of drug absorption,but can significantly delay the time to peak.