BACKGROUND:Spleen has the functions of blood storage,hematopoiesis,and immunity.With the increase of age,the structural degeneration and functional decline of spleen lead to the impairment of immune system function,thus accelerating the aging process of the body.The treatment of spleen aging in tree shrews with highly active umbilical cord mesenchymal stem cells has not been reported. OBJECTIVE:To explore the intervention effect and mechanism of highly active umbilical cord mesenchymal stem cells on spleen aging in tree shrews. METHODS:Highly active umbilical cord mesenchymal stem cells were isolated,cultured,and obtained from the umbilical cord tissue of newborn tree shrews by caesarean section.The differentiation abilities of adipogenesis,osteogenesis,and chondrogenesis were detected by three-line differentiation kit.Cell cycle and surface markers were detected by flow cytometry.The second generation of highly active umbilical cord mesenchymal stem cells were transfected with Genechem Green Fluorescent Protein with infection complex values of 100,120,140,160,180,and 200,respectively,to screen the best transfection conditions.After transfection,the fourth generation of highly active umbilical cord mesenchymal stem cells was injected into the tail vein of tree shrews in the elderly treatment group.The young control group and the aged model group were not given special treatment.After 4 months of treatment,the spleen tissue was taken and the structure of the spleen was observed by hematoxylin-eosin staining.β-Galactosidase staining was used to detect the activity of aging-related galactosidase.Immunohistochemical staining was used to detect the expression levels of p21 and p53 proteins.Ki67 and PCNA immunofluorescence staining was used to detect cell proliferation activity.Immunofluorescence staining was used to detect the expression levels of spleen autophagy protein molecules Beclin 1 and APG5L/ATG5.Reactive oxygen species fluorescence staining was used to detect the content of reactive oxygen species in spleen tissue.CD3 immunofluorescence staining was used to detect the change of the proportion of total T lymphocytes.The secretion levels of interleukin 1β and transforming growth factor β1 in spleen were detected by enzyme linked immunosorbent assay.The distribution of highly active umbilical cord mesenchymal stem cells labeled with green fluorescent protein in spleen tissue was observed by DAPI double staining of nucleus. RESULTS AND CONCLUSION:(1)Highly active umbilical cord mesenchymal stem cells grew in a short spindle shape with fish-like growth,with a large proportion of G0/G1 phase,and had the potential to differentiate into adipogenesis,osteogenesis,and chondrogenesis.(2)Multiplicity of infection=140 and transfection for 72 hours were the best conditions for labeling tree shrews highly active umbilical cord mesenchymal stem cells with Genechem Green Fluorescent Protein.(3)Compared with the aged model group,in the aged treatment group,the spleen tissue cells of tree shrews were arranged closely,and the area of white pulp was increased(P<0.01);the boundary between red pulp and white pulp was clear;the proportion of germinal centers did not show statistically significant difference(P>0.05).The activity level of galactosidase related to spleen tissue aging was decreased(P<0.001),and the expression levels of aging protein molecules p21 and p53 were down-regulated(P<0.001).The expression levels of proliferation-related molecules Ki67 and PCNA were up-regulated(P<0.001,P<0.05);expression levels of autophagy-related molecules Beclin 1 and APG5L/ATG5 were up-regulated(P<0.001),and the content of reactive oxygen species decreased(P<0.001),and the proportion of CD3+T cells increased(P<0.05).The secretion level of interleukin 1β in the aging-related secretion phenotype decreased(P<0.001);no significant difference was found in transforming growth factor β1 level(P>0.05).Compared with the young control group,the above indexes were significantly different in the elderly treatment group(P<0.05).(4)Green fluorescent cells labeled with green fluorescent protein were observed in spleen tissue of tree shrews the elderly treatment group by frozen tissue section observation.The results show that intravenous infusion of highly active umbilical cord mesenchymal stem cells can migrate to spleen tissue,inhibit the production of reactive oxygen species,down-regulate the expression of aging-related proteins,induce autophagy,promote cell proliferation,reduce chronic inflammation,and then improve the structure and function of spleen tissue.

BACKGROUND:Cardiac dysfunction due to spinal cord injury is an important factor of death in patients with spinal cord injury;however,the specific mechanism is still not clear.Therefore,revealing the mechanism of cardiac dysfunction in spinal cord injury patients is of great significance to improve their quality of life and survival rate. OBJECTIVE:To investigate the mechanism of luteolin in improving serum-induced myocardial cell death in spinal cord injury rats. METHODS:Allen's impact instrument was used to damage the spine T9-T11 of male SD rats to establish a spinal cord injury model meanwhile a sham operation group was set as the control group.The serum of rats of each group was collected.H9c2 cells were divided into a blank control group,a sham operated rat serum group,a spinal cord injury rat serum group and a luteolin pretreatment group.The cells in blank control group were only cultured with ordinary culture medium.The cells in the sham operated rat serum group were treated with medium containing 10%serum from sham operated rat.The cells in the spinal cord injury rat serum group were treated with medium containing 10%serum from spinal cord injury rat.The cells in the luteolin pretreatment group were precultured with a final concentration of 20 μmol/L luteolin for 4 hours and then changed to a medium containing 10%rat serum from spinal cord injury rat.After 24 hours of culture,the survival rate of each group of H9c2 cells was measured by CCK-8 assay.Western blot assay was used to detect the expression of autophagy related protein LC3 and p62 in H9c2 cells in each group. RESULTS AND CONCLUSION:Compared with the blank control group,there was no significant change in cell survival rate in the sham operated rat serum group(P>0.05).Compared with the sham operated rat serum group,the cell survival rate(P<0.01)and the expression of LC3 protein(P<0.05)in spinal cord injury rat serum group was significantly reduced,and the expression of p62 protein was significantly increased(P<0.05).Compared with the spinal cord injury rat serum group,the survival rate of cells in the luteolin pretreatment group significantly increased(P<0.000 1);the expression of LC3 protein significantly increased(P<0.05),and the expression of p62 protein significantly decreased(P<0.05).The results indicate that luteolin may improve myocardial cell death induced by serum from rats with spinal cord injury by promoting autophagy.

ObjectiveTo understand the current status of Cronobacter sakazakii (Cronobacter spp.) infection and its molecular epidemiological characteristics among patients with diarrhea, so as to provide evidence for the prevention and control of diarrhea disease caused by infection with Cronobacter spp. in Changping District, Beijing. Methods760 stool samples were collected from the diarrhea patients in a sentinel hospital in 2019, for the detection of Cronobacter spp., Salmonella, diarrheogenic Escherichia coli (DEC), and Vibrio Parahaemolyticus. Meanwhile, drug sensitivity experiment and pulsed-field gel electrophoresis (PFGE) typing analysis were conducted on the Cronobacter spp. strains isolated. ResultsA total of 20 Cronobacter spp. strains (2.63%) were isolated, with a lower detection rate than that of Salmonella and Vibrio Parahaemolyticus (χ²=9.052, P=0.011). However, there were no statistically significant differences between the detection rates in Cronobacter spp. and DEC (χ²=1.076, P=0.300). Seasonal characterization analysis showed that Cronobacter spp. could be detected in spring (1.00%), summer (4.17%), autumn (3.00%) and winter (1.67%), and the differences were statistically significant (χ²=662.700, P<0.001). The PFGE analysis showed that 20 PFGE banding patterns were found in 20 Cronobacter spp. strains, with a similarity coefficient ranging from 56.30% to 90.09% and a diverse PFGE banding pattern. The drug sensitivity experiment results showed that 18 (90.00%) strains were resistant to cefazolin, and2 (10.00%) strains were intermediate. While, as for cefoxitin, 2 (10.00%) strains were resistant to it, and 5 (25.00%) strains were intermediate. All the 20 strains were 100.00% sensitive to the other 11 antibiotics. ConclusionIn the study, Cronobacter spp. is detected in all seasons through the year, with a high resistance rate to cefazolin, no multi-drug resistant bacteria appeared, and diverse PFGE banding patterns.

Aging is accompanied by significant inhibition of hematopoietic and immune system function and disruption of bone marrow structure. Aging-related alterations in the inflammatory response, immunity, and stem cell niches are at the root of hematopoietic aging. Understanding the molecular mechanisms underlying hematopoietic and bone marrow aging can aid the clinical treatment of aging-related diseases. In particular, it is unknown how the niche reprograms hematopoietic stem cells (HSCs) in an age-dependent manner to maintain normal hematopoiesis in elderly individuals. Recently, specific inhibitors and blood exchange methods have been shown to reshape the hematopoietic niche and reverse hematopoietic aging. Here, we present the latest scientific discoveries related to hematopoietic aging and hematopoietic system rejuvenation, discuss the relationships between hematopoietic niche aging and HSC aging, and describe related studies on stem cell-mediated regulation of hematopoietic aging, aiming to provide new ideas for further study.

Objective To explore early postoperative gait characteristics and clinical outcomes after total knee arthroplasty(TKA).Methods From February 2023 to July 2023,26 patients with unilateral knee osteoarthritis(KOA)were treated with TKA,including 4 males and 22 females,aged from 57 to 85 years old with an average of(67.58±6.49)years old;body mass in-dex(BMI)ranged from 18.83 to 38.28 kg·m-2 with an average of(26.43±4.15)kg·m-2;14 patients on the left side,12 pa-tients on the right side;according to Kellgren-Lawrence(K-L)classification,6 patients with grade Ⅲ and 20 patients with grade Ⅳ;the courses of disease ranged from 1 to 14 years with an average of(5.54±3.29)years.Images and videos of standing up and walking,walking side shot,squatting and supine kneeling were taken with smart phones before operation and 6 weeks after operation.The human posture estimation framework OpenPose were used to analyze stride frequency,step length,step length,step speed,active knee knee bending angle,stride length,double support phase time,as well as maximum hip flexion angle and maximum knee bending angle on squatting position.Western Ontario and McMaster Universities(WOMAC)arthritis index and Knee Society Score(KSS)were used to evaluate clinical efficacy of knee joint.Results All patients were followed up for 5 to 7 weeks with an average of(6.00±0.57)weeks.The total score of WOMAC decreased from(64.85±11.54)before op-eration to(45.81±7.91)at 6 weeks after operation(P＜0.001).The total KSS was increased from(101.19±9.58)before opera-tion to(125.50±10.32)at 6 weeks after operation(P＜0.001).The gait speed,stride frequency and stride length of the affected side before operation were(0.32±0.10)m·s-1,(96.35±24.18)steps·min-1,(0.72±0.14)m,respectively;and increased to(0.48±0.11)m·s 1,(104.20±22.53)steps·min-1,(0.79±0.10)m at 6 weeks after operation(P＜0.05).The lower limb support time and active knee bending angle decreased from(0.31±0.38)sand(125.21±11.64)° before operation to(0.11±0.04)s and(120.01±13.35)° at 6 weeks after operation(P＜0.05).Eleven patients could able to complete squat before operation,13 patients could able to complete at 6 weeks after operation,and 9 patients could able to complete both before operation and 6 weeks after operation.In 9 patients,the maximum bending angle of crouching position was increased from 76.29° to 124.11° before operation to 91.35° to 134.12° at 6 weeks after operation,and the maximum bending angle of hip was increased from 103.70° to 147.25° before operation to 118.61° to 149.48° at 6 weeks after operation.Conclusion Gait analysis technology based on artificial intelligence image recognition is a safe and effective method to quantitatively identify the changes of pa-tients'gait.Knee pain of KOA was relieved and the function was improved,the supporting ability of the affected limb was im-proved after TKA,and the patient's stride frequency,stride length and stride speed were improved,and the overall movement rhythm of both lower limbs are more coordinated.

To evaluate the effectiveness and safety of implantable D-shant atrial shunt device in patients with severe pulmonary arterial hypertension(PAH)and right heart failure.A 53-year-old female patient diagnosed with severe idiopathic PAH and right heart failure,her WHO FC grade was Ⅳ.The right heart catheter and implantation of D-shant atrial shunt device were performed under local anesthesia on November 30,2021.A 6 mm×4 cm peripheral artery balloon was selected to dilate the atrial septum and a D-shant atrial shunt device with a fixed 4 mm diameter orifice was implanted into the heart.The clinical symptoms and hemodynamics of the patient was improved after the intervention.Implantation of atrial shunt device as a palliative therapy to established a right to left shunt is another strategy for treating patients with severe PAH in late period,which has good effectiveness and safety.It could be the last replacement therapy to improve symptoms and prolonged lives to drug resistant and severe PAH 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]

Objective To construct the demand model of four types of medical resources including beds in hospi-tal,beds in intensive care unit(ICU),ventilators and medical human resources during the major infectious disease epidemic events,simulate and analyze the treatment of infectious diseases when different medical resources are in short supply.Methods Based on the susceptible-exposed-infectious-recovered(SEIR)model,considering the infec-tivity of infected persons,the susceptibility of the population and the immunity of convalescents,the characteristics of asymptomatic COVID-19 patients and different clinical types,the"COVID-19 infection-hospitalization model"was constructed.By collecting and setting the parameters of disease transmission,clinical course and medical re-source shortage scenarios,an analysis model of allocation and supply of urban medical resources during infectious di-sease epidemic events was initially formed based on Anylogic platform,the supply and demand of medical resources during infectious disease events in different scenarios were analyzed.Results In the non-intervention scenario,the peak time of bed demand was on the 107th day,and the peak value was 160.92 beds per thousand people;the peak time of ventilator demand was on the 122nd day,and the peak value was 5.61 units per thousand people;the peak time of ICU bed demand was on the 117th day,and the peak value was 12.78 beds per thousand people;the peak time of the demand for medical human resources was on the 109th day,and the peak value was 151.12 persons per thousand persons.The simulation results suggested that there were some differences in the impact of different medi-cal resources on the outcome of medical treatment.Conclusion This study constructs an analytical tool for the allo-cation and supply of urban medical resources under the epidemic events of infectious diseases,and the results of mul-tiple simulation experiments suggest that bed resources and medical human resources play more important roles in the outcome of medical treatment.

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 level of deltamethrin resistance and mutation sites in the sodium iron channel gene in Rhipicephalus microplus in Huaihua City, Hunan Province, and to examine the correlation between deltamethrin resistance and mutation sites in the sodium iron channel gene in Rh. microplus. Methods Rh. microplus was sampled from multiple yellow cattle farms in Huaihua City, Hunan Province from June to September 2022, and the level of resistance to deltamethrin was determined in ticks using the adult immersion test. The sodium iron channel domain III gene was amplified in deltamethrin-resistant and wild-type Rh. microplus using PCR assay. Following sequencing and sequence alignment, mutation sites were detected in bases. The sodium iron channel domain III gene in Rh. microplus was translated, and the signal peptide, transmembrane domain, and phosphorylation and glycosylation sites were detected in amino acid sequences. The tertiary structures of the sodium iron channel domain III protein of deltamethrin-resistant and wild-type Rh. microplus were deduced and compared, and the association be tween mutation sites in bases and resistance to deltamethrin was examined in Rh. microplus according the level of deltamethrin resistance, sequence alignment and protein tertiary structure. Results The median (LC₅₀) and 95% lethal concentrations (LC₉₅) of deltamethrin were 121.39 mg/L and 952.61 mg/L against Rh. microplus, with a resistance factor of 9.24 and level II resistance. The sequence of the sodium ion channel domain III gene was 1 010 bp in size, and mutation sites were detected in two neighboring bases in the sequence of the sodium ion channel domain III gene in deltamethrin-resistant Rh. microplus. Although no signal peptides were found in the sodium iron channel domain III protein of deltamethrin-resistant or wild-type Rh. microplus, 6 trans-membrane domains, 42 phosphorylation sites and 8 glycosylation sites were identified, with a significant difference in the tertiary structure of the sodium iron channel domain III protein between deltamethrin-resistant and wild-type Rh. microplus. Conclusions Level II resistance to deltamethrin is detected in Rh. microplus in Huaihua City, Hunan Province, and two mutation sites that correlate with the emergence of deltamethrin resistance are identified in the sequence of the sodium iron channel domain III gene in deltamethrin-resistant Rh. microplus.