Objective:To analyze the clinical and radiographic effectiveness of a calcium silicate-based bioactive ceramic iRoot BP Plus? pulpotomy of immature permanent teeth with complicated crown fracture and to evaluate the factors influencing its long-term success rate.Methods:The digital medical records of patients under 13 years old who had undergone iRoot BP Plus? pulpotomy in the Department of Oral Emergency or the First Clinical Division,Peking University School and Hospital of Stomatology from March 2017 to September 2022 due to complicated crown fracture of anterior teeth,and had taken at least one post-operation apical radiograph were reviewed.The clinical and radiographic information at the initial examination and follow-up period were obtained,including crown color,mobility,percussion,cold test(partial pulpotomy teeth),dental restoration,fistula,swelling or inflammation of the gingival tissue,the formation of apical foramen,pathologic radiolucency and calcification of pulp chamber or root canal obliteration.Data were tested by Fisher exact test and a multiple comparison.Results:In the study,64 patients including 37 males(57.8％)and 27 females(42.2％)with a mean age of 9.1 years were finally enrolled.The total number of permanent teeth that received pulpotomy was 75,and the average follow-up time was 19.3 months.The success rate was 93.1％with the time interval between dental injury and treatment in 24 h,while the success rate dropped to 88.2％with the time intervals beyond 24 h.The time intervals did not significantly affect the pulp survival rate(P=0.61)after pulpotomy(partial or co-ronal).The success rate 6 months after pulpotomy was 96.0％,and one-year success rate was 94.7％.A total of 23 cases were reviewed for more than 2 years after pulpotomy,and 6 cases failed.The mobility had no significant effect on the success rate(P=0.28).Pulp chamber calcification and pulp canal obli-teration were not observed in all the post-operative radiographs.Conclusion:The one year clinical and radiographic success rates obtained in this study indicate that iRoot BP Plus? is an appropriate pulp cap-ping material option for pulpotomy treatment of complicated crown fracture in immature permanent teeth without displacement injuries.This technique has broad promotional value.

Objective:With the in-depth study of complement dysregulation,glomerulonephritis with dominant C3 has received increasing attention,with a variety of pathologic types and large differences in symptoms and prognosis between pathologic types.This study analyzes the clinical,pathological,and prognostic characteristics of different pathological types of glomerulonephritis with dominant C3,aiming to avoid misdiagnosis and missed diagnoses. Methods:The clinical,pathological,and follow-up data of 52 patients diagnosed as glomerulonephritis with dominant C3 by renal biopsy from June 2013 to October 2022 were retrospectively analyzed.According to the clinical feature and results of pathology,15 patients with post-infectious glomerulonephritis(PIGN)and 37 patients with of non-infectious glomerulonephritis(N-PIGN)were classified.N-PIGN subgroup analysis was performed,and 16 patients were assigned into a C3-alone-deposition group and 21 in a C3-dominant-deposition group,or 27 in a C3 glomerulopathy(C3G)group and 10 in a non-C3 nephropathy(N-C3G)group. Results:The PIGN group had lower creatinine values(84.60 μmol/L vs 179.62 μmol/L,P= 0.001),lower complement C3 values(0.36 g/L vs 0.74 g/L,P<0.001)at biopsy,and less severe pathological chronic lesions compared with the N-PIGN group.In the N-PIGN subgroup analysis,the C3-dominant-deposition group had higher creatinine values(235.30 μmol/L vs 106.70 μmol/L,P=0.004)and higher 24-hour urine protein values(4 025.62 mg vs 1 981.11 mg,P=0.037)than the C3-alone-deposition group.The prognosis of kidney in the PIGN group(P=0.049),the C3-alone-deposition group(P=0.017),and the C3G group(P=0.018)was better than that in the N-PIGN group,the C3-dominant-deposition group,and the N-C3G group,respectively. Conclusion:Glomerulonephritis with dominant C3 covers a variety of pathological types,and PIGN needs to be excluded before diagnosing C3G because of considerable overlap with atypical PIGN and C3G;in addition,the deposition of C1q complement under fluorescence microscope may indicate poor renal prognosis,and relevant diagnosis,treatment,and follow-up should be strengthened.

BACKGROUND:As tissue engineering brings new hope to the worldwide problem of articular cartilage repair,the construction of light-curing 3D printed hydrogel scaffolds with biomimetic composition is of great significance for cartilage tissue engineering. OBJECTIVE:To construct a biomimetic methacryloylated hyaluronic acid/acellular Wharton's jelly composite hydrogel scaffold by digital light processing 3D printing technology,and to evaluate its biocompatibility. METHODS:Wharton's jelly was isolated and extracted from human umbilical cord,then decellulated,freeze-dried,ground into powder,and dissolved in PBS to prepare 50 g/L acellular Wharton's jelly solution.Methylallylated hyaluronic acid was prepared,lyophilized and dissolved in PBS to prepare 50 g/L methylallylated hyaluronic acid solution.Acellular Wharton's jelly solution was mixed with methacrylyacylated hyaluronic acid solution at a volume ratio of 1:1,and was used as bio-ink after adding photoinitiator.Methylacrylylated hyaluronic acid hydrogel scaffolds(labeled as HAMA hydrogel scaffolds)and methylacrylylated hyaluronic acid/acellular Wharton's jelly gel scaffolds(labeled as HAMA/WJ hydrogel scaffolds)were prepared by digital light processing 3D printing technology,and the microstructure,swelling performance,biocompatibility,and cartilage differentiation performance of the scaffolds were characterized. RESULTS AND CONCLUSION:(1)Under scanning electron microscope,the two groups of scaffolds showed a three-dimensional network structure,and the fiber connection of HAMA/WJ hydrogel scaffold was more uniform.Both groups achieved swelling equilibrium within 10 hours,and the equilibrium swelling ratio of HAMA/WJ hydrogel scaffold was lower than that of HAMA hydrogel scaffold(P＜0.05).(2)CCK-8 assay showed that HAMA/WJ hydrogel scaffold could promote the proliferation of bone marrow mesenchymal stem cells compared with HAMA hydrogel scaffold.Dead/live staining showed that bone marrow mesenchymal stem cells grew well on the two groups of scaffolds,and the cells on the HAMA/WJ hydrogel scaffolds were evenly distributed and more cells were found.Phalloidine staining showed better adhesion and spread of bone marrow mesenchymal stem cells in HAMA/WJ hydrogel scaffold than in HAMA.(3)Bone marrow mesenchymal stem cells were inoculated into the two groups for chondrogenic induction culture.The results of qRT-PCR showed that the mRNA expressions of agglutinoglycan,SOX9 and type Ⅱ collagen in the HAMA/WJ hydrogel scaffold group were higher than those in the HAMA hydrogel scaffold group(P＜0.05,P＜0.01).(4)These findings indicate that the digital light processing 3D bioprinting HAMA/WJ hydrogel scaffold can promote the proliferation,adhesion,and chondrogenic differentiation of bone marrow mesenchymal stem cells.

ObjectiveTo investigate the effect of Rehmanniae Radix Praeparata on neurological function injury in ischemic stroke rats and explore its mechanism. MethodMale SD rats were randomized into sham operation， model， low- and high -dose （3.5 g·kg^-1 and 7 g·kg^-1） Rehmannia Radix Praeparata， and nimodipine （0.01 g·kg^-1） groups. The rat model of middle cerebral artery occlusion （MCAO） was established with the modified suture occlusion method. Zea-Longa 5-point scoring was employed to evaluate the neurological function of rats. The cerebral infarction volume was detected by 2，3，5-triphenyltetrazolium chloride （TTC） staining. Hematoxylin-eosin staining and Nissl staining were employed to observe the morphology and damage of the brain tissue. Meanwhile， the serum levels of lactate dehydrogenase （LDH）， oxidative stress-related indicators superoxide dismutase （SOD）， glutathione peroxidase 4 （GPX4）， and malondialdehyde （MDA）， and the iron （Fe） content in the brain tissue were determined. To explore the mechanism of Rehmanniae Radix Preparata in mitigating the neurological damage in ischemic stroke rats， Western blotting was employed to determine the expression levels of proteins in the ischemic brain tissue. The autophagy-associated proteins included autophagy effector （beclin-1）， microtubule-associated protein light chain 3 （LC3B）， and ubiquitin-binding protein p62 （p62）. The ferroptosis-associated proteins included transferrin （TF）， transferrin receptor 1 （TFR1）， ferritin heavy chain 1 （FTH1）， and ferropotin （FPN1）. The neurological function injury-associated proteins included brain-derived neurotrophic factor （BDNF） and tyrosine kinase receptor B （TrkB）. ResultCompared with the sham operation group， the model group showed increased neurological function score， cerebral infarction volume， and appearance of nuclear pyknosis and vacuole of cells in the cerebral cortex. In addition， the model group presented elevated levels of LDH， MDA， and Fe （P<0.01） and lowered levels of SOD and GPX4 （P<0.01）. Compared with the model group， Rehmanniae Radix Praeparata decreased the content of LDH， MDA， and Fe （P<0.05， P<0.01） and elevated the levels of SOD and GPX4 （P<0.05， P<0.01）. Compared with the sham operation group， the modeling promoted the expression of beclin-1，LC3B Ⅱ/Ⅰ， TF， and TFR1 and inhibited the expression of p62， FTH1， FPN1， BDNF， and TrkB （P<0.01）. The expression levels of these proteins were recovered after the treatment with Rehmanniae Radix Praeparata. ConclusionRehmanniae Radix Praeparata may inhibit ferroptosis and improve the neurological function in ischemic stroke rats by down-regulating the autophagy level in the brain tissue.

Objective:To investigate the effects of wza gene deletion in Klebsiella pneumoniae on capsule formation ability and bacteriophage sensitivity. Methods:The wza deletion mutant strain was constructed through a temperature-sensitive plasmid-mediated homologous recombination. The growth curves of W14 and Δ wza were detected by measuring the optical density OD 600. In order to analyze the effect of gene wza on bacterial capsule formation, wild-type strain W14 and Δ wza mutant strain were detected by transmission electron microscope, and their capsule contents were measured by quantifying the uronic acid contents. The plaque assay was used to detect bacterial sensitivity to bacteriophage in wild-type strain W14 and Δ wza mutant strain. The t test was used to compare whether there were differences in the contents of uronic acid in the capsules of wild-type strain W14 and Δ wza mutant strain. Results:The PCR results revealed that the Δ wza mutant strain was successfully constructed. Compared with wild-type strain W14, the growth curves of Δ wza on the solid plates demonstrated a slightly slower growth. However, no difference in growth was observed among wild-type strain W14 and Δ wza mutant strains in LB broth. The transmission electron microscope results showed that wza gene deletion resulted in the loss of capsule in bacteria. The uronic acid content assay suggested that the capsule content was significantly decreased in Δ wza mutant strain (45.963±2.795) μg/ml compared with wild-type strain W14 (138.800±5.201) μg/ml. There was a statistical difference between the two groups ( t=27.233, P<0.001). The plaque assay indicated that bacteria lost its sensitivity to bacteriophage when gene wza was deleted. Conclusion:Deletion of the wza gene impairs bacterial capsule formation ability and can affect bacterial sensitivity to bacteriophage phiW14.

Objective:To express and purify the phage depolymerase from hypervirulent Klebsiella pneumoniae (hv Kp) serotype K1 and validate its function. Methods:Phage that infected serotype K1-type hv Kp was isolated from hospital sewage. The biology and morphology of the phage were determined by plaque assay and transmission electron microscopy. The whole genome of the phage was sequenced by the Illumina HiSeq 2500 platform. The presence of depolymerase was determined by observing the plaque halo. Bioinformatic analysis and prokaryotic protein expression system were further used to predict and identify phage depolymerase. The depolymerase gene fragment was obtained by PCR and cloned into the pET28a expression vector, and the expression and purification of the depolymerase were completed in strain BL21. The depolymerase activities on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates were detected by plaque assay and low-speed centrifugation assay. Results:A lytic phage (phiA2) that infected serotype K1-type hv Kp clinical isolate was isolated from hospital sewage. It was typical of the Caudovirales order and Autographiviridae family, and its whole genome was 43 526 bp in length and contained 51 coding domain sequences. The phage phiA2-derived depolymerase phiA2-dep was predicted, expressed and purified. The plaque assay and low-speed centrifugation assay indicated that the depolymerase phiA2-dep had good lytic activity on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates. Conclusion:Depolymerase phiA2-dep can specifically degrade the capsular polysaccharide of serotype K1-type hv Kp, which has potential application value in treating bacterial infection.

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.

Objective:To investigate the effects of wza gene deletion in Klebsiella pneumoniae on capsule formation ability and bacteriophage sensitivity. Methods:The wza deletion mutant strain was constructed through a temperature-sensitive plasmid-mediated homologous recombination. The growth curves of W14 and Δ wza were detected by measuring the optical density OD 600. In order to analyze the effect of gene wza on bacterial capsule formation, wild-type strain W14 and Δ wza mutant strain were detected by transmission electron microscope, and their capsule contents were measured by quantifying the uronic acid contents. The plaque assay was used to detect bacterial sensitivity to bacteriophage in wild-type strain W14 and Δ wza mutant strain. The t test was used to compare whether there were differences in the contents of uronic acid in the capsules of wild-type strain W14 and Δ wza mutant strain. Results:The PCR results revealed that the Δ wza mutant strain was successfully constructed. Compared with wild-type strain W14, the growth curves of Δ wza on the solid plates demonstrated a slightly slower growth. However, no difference in growth was observed among wild-type strain W14 and Δ wza mutant strains in LB broth. The transmission electron microscope results showed that wza gene deletion resulted in the loss of capsule in bacteria. The uronic acid content assay suggested that the capsule content was significantly decreased in Δ wza mutant strain (45.963±2.795) μg/ml compared with wild-type strain W14 (138.800±5.201) μg/ml. There was a statistical difference between the two groups ( t=27.233, P<0.001). The plaque assay indicated that bacteria lost its sensitivity to bacteriophage when gene wza was deleted. Conclusion:Deletion of the wza gene impairs bacterial capsule formation ability and can affect bacterial sensitivity to bacteriophage phiW14.

Objective:To express and purify the phage depolymerase from hypervirulent Klebsiella pneumoniae (hv Kp) serotype K1 and validate its function. Methods:Phage that infected serotype K1-type hv Kp was isolated from hospital sewage. The biology and morphology of the phage were determined by plaque assay and transmission electron microscopy. The whole genome of the phage was sequenced by the Illumina HiSeq 2500 platform. The presence of depolymerase was determined by observing the plaque halo. Bioinformatic analysis and prokaryotic protein expression system were further used to predict and identify phage depolymerase. The depolymerase gene fragment was obtained by PCR and cloned into the pET28a expression vector, and the expression and purification of the depolymerase were completed in strain BL21. The depolymerase activities on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates were detected by plaque assay and low-speed centrifugation assay. Results:A lytic phage (phiA2) that infected serotype K1-type hv Kp clinical isolate was isolated from hospital sewage. It was typical of the Caudovirales order and Autographiviridae family, and its whole genome was 43 526 bp in length and contained 51 coding domain sequences. The phage phiA2-derived depolymerase phiA2-dep was predicted, expressed and purified. The plaque assay and low-speed centrifugation assay indicated that the depolymerase phiA2-dep had good lytic activity on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates. Conclusion:Depolymerase phiA2-dep can specifically degrade the capsular polysaccharide of serotype K1-type hv Kp, which has potential application value in treating bacterial infection.

Objective To understand the change in distribution and antimicrobial resistance of bacteria isolated from blood specimens of Hunan Province,and provide for the initial diagnosis and treatment of clinical bloodstream infection(BSI).Methods Data reported from member units of Hunan Province Antimicrobial Resistance Survei-llance System from 2012 to 2021 were collected.Bacterial antimicrobial resistance surveillance method was imple-mented according to the technical scheme of China Antimicrobial Resistance Surveillance System(CARSS).Bacteria from blood specimens and bacterial antimicrobial susceptibility testing results were analyzed by WHONET 5.6 soft-ware and SPSS 27.0 software.Results A total of 207 054 bacterial strains were isolated from blood specimens from member units in Hunan Province Antimicrobial Resistance Surveillance System from 2012 to 2021,including 107 135(51.7％)Gram-positive bacteria and 99 919(48.3％)Gram-negative bacteria.There was no change in the top 6 pathogenic bacteria from 2012 to 2021,with Escherichia coli(n=51 537,24.9％)ranking first,followed by Staphylococcus epidermidis(n=29 115,14.1％),Staphylococcus aureus(n=17 402,8.4％),Klebsiella pneu-moniae(17 325,8.4％),Pseudomonas aeruginosa(n=4 010,1.9％)and Acinetobacter baumannii(n=3 598,1.7％).The detection rate of methicillin-resistant Staphylococcus aureus(MRSA)decreased from 30.3％in 2015 to 20.7％in 2021,while the detection rate of methicillin-resistant coagulase-negative Staphylococcus(MRCNS)showed an upward trend year by year(57.9％-66.8％).No Staphylococcus was found to be resistant to vancomy-cin,linezolid,and teicoplanin.Among Gram-negative bacteria,constituent ratios of Escherichia coli and Klebsiella pneumoniae were 43.9％-53.9％and 14.2％-19.5％,respectively,both showing an upward trend(both P＜0.001).Constituent ratios of Pseudomonas aeruginosa and Acinetobacter baumannii were 3.6％-5.1％and 3.0％-4.5％,respectively,both showing a downward trend year by year(both P＜0.001).From 2012 to 2021,resistance rates of Escherichia coli to imipenem and ertapenem were 1.0％-2.0％and 0.6％-1.1％,respectively;presenting a downward trend(P＜0.001).The resistant rates of Klebsiella pneumoniae to meropenem and ertapenem were 7.4％-13.7％and 4.8％-6.4％,respectively,presenting a downward trend(both P＜0.001).The resistance rates of Pseudomonas aeruginosa and Acinetobacter baumannii to carbapenem antibiotics were 7.1％-15.6％and 34.7％-45.7％,respectively.The trend of resistance to carbapenem antibiotics was relatively stable,but has de-creased compared with 2012-2016.The resistance rates of Escherichia coli to the third-generation cephalosporins from 2012 to 2021 were 41.0％-65.4％,showing a downward trend year by year.Conclusion The constituent ra-tio of Gram-negative bacillus from blood specimens in Hunan Province has been increasing year by year,while the detection rate of carbapenem-resistant Gram-negative bacillus remained relatively stable in the past 5 years,and the detection rate of coagulase-negative Staphylococcus has shown a downward trend.