OBJECTIVE To investigate the metabolic changes in MEG-01 megakaryocytes after treatment with linezolid （LZD） from metabolomic perspective and its impact on the the proliferation of cells and generation of platelet precursors. METHODS MEG-01 cells were seeded in proliferation medium and divided into blank control group （untreated）， solvent control group （4‰DMSO）， and 100， 200， 400， 800 μg/mL LZD groups. The proliferation status of cells in each group was observed under the microscope； cell proliferation and viability were assessed. Cells were also seeded in differentiation medium and divided into blank control group （untreated）， solvent control group （4‰DMSO）， and 400 μg/mL LZD group； after 14 days of culture， platelet precursor generation was observed under the microscope； immunofluorescence staining was performed to count the proportion of cells producing pseudopodia， the relative length of pseudopodia was measured， and the expression levels of CD41 and CD42b mRNA were assessed. Cells from the solvent control group and the 400 μg/mL LZD group， cultured in differentiation medium for 14 days， were extracted and subjected to non-targeted metabolomics and targeted energy metabolomics analysis using liquid chromatography-tandem mass spectrometry. The relative content of pyruvate in cells， after being cultured for 14 days with the addition of pyruvate （10 mmol/L） or LZD （400 μg/mL）+pyruvate （10 mmol/L）， was measured and observed， as well as its effects on cell proliferation and platelet precursor generation. RESULTS 400 μg/mL LZD could significantly inhibit the proliferation of MEG-01 cells and the generation of platelet precursors （P＜0.01）. Non-targeted metabolomic analysis of MEG-01 cells after 400 μg/mL LZD treatment revealed significant changes in energy metabolism-related pathways such as mTOR signaling pathway， alanine， aspartate and glutamate metabolism， and central carbon metabolism in cancer. Targeted energy metabolomic analysis further showed that the relative contents of adenosine triphosphate， guanosine triphosphate， and pyruvate in MEG-01 cells were significantly reduced （P＜0.01）， while the relative contents of lactate were significantly increased （P＜0.01）. Compared with the LZD group， the relative content of pyruvate， cell count， the proportion of cells producing pseudopodia and the relative length of pseudopodia were significantly increased in the LZD+pyruvate group （P＜0.01）. CONCLUSIONS LZD may reduce pyruvate production by inhibiting mitochondrial energy metabolism， thereby suppressing megakaryocyte proliferation and platelet precursor production， ultimately leading to the occurrence of thrombocytopenia.

Objective: To retrospectively analyze the epidemiological characteristics of supernumerary teeth in patients aged 4-18 years old and the influencing factors on the selection of anesthesia methods, and to provide a reference for the selection of anesthesia plans for children and adolescents with supernumerary teeth. Methods: This study is a retrospective study approved by the Institutional Ethics Committee. Based on clinical electronic medical record system and cone beam CT (CBCT) data, a retrospective analysis was conducted on 2 210 patients 4-18 years of age who underwent supernumerary tooth extraction at the School of Stomatology, Fourth Military Medical University from August 2019 to July 2021. Inclusion criteria: ① Age 4-18 years old; and ② The American Society of Anesthesiologists (ASA) classifies anesthesia into grades I-II; and ③ Have complete oral and anesthesia case records and relevant imaging data. Exclusion criteria: ① Incomplete medical records or unclear imaging data; and ② Patients with ASA grade II or above. Patients’ gender and age, the number of supernumerary teeth, arch, location, orientation, eruption status, reason for appointment, anxiety level, degree of cooperation, anesthesia method, and other relevant information were collected and statistically analyzed. Results: A total of 1 865 eligible patients were included, with an average age of (8.9±3.2) years old. There were more male patients (71.37%, 1 331 cases) than female patients (28.63%, 534 cases) (P < 0.001), with a gender ratio of 2.49:1. The majority of supernumerary teeth were single (75.97%, 1 417/1 865), primarily located in the maxilla (97.2%, 1 812/1 865) and the anterior dental region (94.2%, 1 757/1 865), and in a centric position (77.3%, 1 442/1 865). The majority of patients with erupted supernumerary teeth were active in seeking treatment (97.67%, 335/343). Patients with supernumerary teeth located in the maxilla and mandible bones, as well as in the nasal floor, were mainly referred to the department for diagnosis, accounting for 94.38%(1 361/1 442) and 90.00% (72/80) (χ2=1 363.24, P < 0.001), respectively. Regarding anesthesia methods, the largest proportion of patients received nitrous oxide sedation-assisted local anesthesia or nerve block anesthesia, accounting for 38.07% (710/1 865), followed by local anesthesia, accounting for 35.23% (657/1 865). The proportion of patients receiving midazolam intravenous sedation with local anesthesia or nerve block anesthesia and general anesthesia was relatively small, accounting for 20.86% (389/1 865) and 5.84% (109/1 865). Patients 13-18 years of age with supernumerary teeth in the mandibular and posterior regions and without anxiety had the highest proportion of local anesthesia use (P < 0.001). In contrast, patients who had supernumerary teeth located at the base of the nose (50%), severe anxiety (94.12%), and poor cooperation (98.18%) had the highest proportion of general anesthesia use (P < 0.001). There was no significant difference (P = 0.35) in the incidence of intraoperative and postoperative complications after the extraction of supernumerary teeth. However, the proportion of anesthesia-related complications, such as dizziness, coughing, and respiratory depression, occurring in patients who received general anesthesia was higher than local anesthesia, accounting for 3.81% (P = 0.006). Conclusion There is a gender difference in the incidence of supernumerary teeth in patients 4-18 years of age, with a higher prevalence in males. The majority of supernumerary teeth are single and located in the maxillary anterior region, predominantly in a centric position. Patients whose teeth had erupted were more likely to seek medical treatment voluntarily, while patients with supernumerary teeth located in the maxilla and mandible bones, as well as in the nasal floor were more likely to be referred to the department. Patients with high levels of anxiety, poor cooperation, young age, multiple teeth, and high surgical difficulty were more inclined to choose general anesthesia.

Objective To observe the value of SimGrid(SG)and S-Enhance(SE)for improving image quality of low-dose X-ray films in children.Methods Data of 344 children in intensive care unit who underwent 410 times bedside X-ray examinations,including 290 times of chest X-ray,51 of abdominal X-ray and 69 of chest and abdominal combined X-ray were enrolled.SG and SE were respectively used for post-processing,and the quality of post-processed images were analyzed.Results Among 410 SG post-processing images,250 images were classified as 2-point,147 as 1-point and 13 as 0-point.SG could significantly improve image quality of children≥1 year and body mass≥10 kg(all P＜0.05),with better ability for displaying bones,trachea,peripheral blood vessels,foreign objects,psoas major muscle and intestinal gas(all P＜0.05).Among 410 SE post-processing images,250 images were classified as 2-point,58 as 1-point and 102 of 0-point.SE could significantly improve image quality of children≥0.5 years and with body mass＞4 kg(all P＜0.05),with better ability for displaying bones,trachea,large blood vessels,peripheral vessels,heart posterior blood vessels and foreign objects(all P＜0.05).Conclusion SG could significantly improve displaying of bones,trachea,peripheral blood vessels,foreign objects,psoas major muscle and intestinal gas in children≥1 year and body mass≥10 kg,while SE could improve displaying of bones,trachea,large blood vessels,peripheral blood vessels,heart posterior blood vessels and foreign objects in children aged≥0.5 years and body mass＞4 kg on low-dose X-ray films.

Objective:To evaluate clinical efficacy and safety of immunotherapy by retrospectively analyzing clinical medica-tion of patients with recurrent pregnancy loss(RPL)complicated with abnormal immune factors.Methods:A retrospective cohort study was conducted on RPL cases in outpatient department of Hebei Reproductive Health Hospital from January 2021 to April 2022.Efficacy and safety of immunotherapy were evaluated from pregnancy outcome,adverse reactions and birth defects of offspring.Results:According to guidelines,192 cases with abnormal autoimmunity and/or immune indicators were included.Early abortion rate was 4.16%in group of two lost pregnancies,which was lower than that in group of three lost pregnancies(16.66%).Twelve week sus-tained pregnancy rate was 89.58%in the former group,and 28 week sustained pregnancy rate was 86.45%,which were significantly higher than those in the latter group(75.00%,71.87%).RPL patients were divided into groups according to their exposure to immuno-modulatory drugs before 12 weeks of pregnancy.There was no significant difference in pregnancy outcome,adverse reaction rate and birth defect rate of their offspring(P>0.05).Conclusion:Immunotherapy can effectively reduce risk of recurrent abortion and increase rate of persistent pregnancy in patients with immune RPL.Personalized immunotherapy can make RPL patients with immune factors achieve expected effect of fetal protection.

Objective:To construct an explainable artificial intelligence(AI) model of risk characteristics of papillary thyroid carcinoma(PTC), and to explore its value of it combined with clinical features in predicting cervical lymph node metastasis(CLNM) in PTC patients.Methods:From January 2021 to September 2022, 422 patients(422 nodules) with pathologically confirmed PTC underwent thyroidectomy and neck lymph node dissection in the Second Affiliated Hospital of Xi′an Jiaotong University were retrospectively collected, the patients were randomly divided into training set and test set according to the ratio of 7∶3. Ultrasonographic features highly correlated with PTC risk characteristics were extracted by traditional machine learning method, and an intelligent prediction model with optimal probability of risk characteristics was established. Then, a risk model for predicting CLNM of PTC patients was constructed in combination with clinical features. The diagnostic effectiveness of the model was evaluated by drawing a ROC curve and calculating the area under curve (AUC).Results:In the AI explaineable model of PTC risk characteristics in the test set, the intelligent diagnosis model of calcification based on logistic regression classification showed the highest diagnostic efficiency, with an AUC of 0.87 ( P<0.05). Compared with the probability model of risk characteristic of PTC alone, the comprehensive model combined with clinical characteristics showed higher diagnostic efficiency in predicting CLNM of PTC patients, with AUC of 0.97, diagnostic critical value of 0.15, corresponding accuracy, sensitivity and specificity of 92.65%, 92.76% and 92.54%, respectively (all P<0.05). Conclusions:The explaineble risk characteristics of PTC AI model combined with clinical features can effectively predict the cervical lymph node metastasis of PTC, and then provide effective information for clinical decision-making of PTC patients.

Objective:To understand the molecular characteristics of the mutant strain of polymerase basic protein 2 (PB2) gene of influenza A (H1N1pdm) in Guangdong province, and to explore its specific molecular sites, so as to provide scientific basis for the prevention and control of influenza virus.Methods:Throat swab samples were collected from 2 cases infected with PB2 gene variant strains for virus isolation, and 23 influenza virus strains were selected from Guangdong province for sequencing analysis. The reference sequences and vaccine strain sequences provided by GISAID were used to perform evolutionary analysis on hemagglutinin (HA) and PB2 genes. Virus strain antigen analysis and neuraminidase (NA) inhibition test were carried out. PB2 protein model was constructed and polymerase activity was analyzed.Results:H399N amino acid mutation occurred in the HA gene of PB2-D701N and PB2-A271S variant strains, both of which belonged to the branch of 6B.1A.5a.2a. They belonged to the same big branch and different small branches as the vaccine strain A/Victoria/4897/2022, and they are all vaccine-like strains. In the three-dimensional structure, the mutations of PB2-D701N and PB2-A271S change charge and hydrophobicity.Conclusions:PB2-D701 and A271 were highly conserved, and PB2 mutant strains were not the dominant strains. The PB2 mutant had high antigenicity with the vaccine. The PB2 mutant strain is sensitive to NA inhibitors. The three-dimensional model predicted that PB2-D701N mutation could enhance virulence and affect transmissibility of influenza virus, while PB2-A271S mutation could affect polymerase activity and polymerase complex synthesis of influenza virus.

Spastic paraplegia type 4 (SPG4) is the most common type of autosomally inherited spastic paraplegia. Its main clinical features include typical simple hereditary spastic paraplegia, with neurological impairments limited to lower limb spasticity, hypertonic bladder dysfunction, and mild weakening of lower limb vibration sensation, without accompanying features such as nerve atrophy, ataxia, cognitive impairment, seizures, and muscle tone disorders. SPAST is the main pathogenic gene underlying SPG4, and various pathogenic SPAST variants have been discovered. This disease has featured a high degree of clinical heterogeneity, and the same pathogenic variant can have different age of onset and severity among patients and even within the same family. There is a lack of systematic research on the correlation between the genotype and phenotype of SPG4, and the pathogenic mechanism has remained controversial. This article has provided a review for the clinical characteristics, pathogenic gene characteristics, correlation between the genotype and phenotype, and pathogenic mechanism of this disease, with an aim to provide reference for its clinical diagnosis and treatment.

BACKGROUND:Ankylosing spondylitis is a chronic inflammatory disease with chronic rheumatic immunity.Soft tissue ossification and fusion and spinal stiffness can cause biomechanical changes. OBJECTIVE:To reconstruct the lumbar-sacral intervertebral disc in ankylosing spondylitis patients with lumbar kyphosis by finite element analysis,and to study the range of motion of each segment of T11-S1 and the biomechanical characteristics of annulus fibrosus and nucleus pulposus. METHODS:The imaging data were obtained from an ankylosing spondylitis patient with lumbar kyphosis.The original CT image data of continuously scanned spine were imported into Mimics 21.0 in DICOM format,and T11-S1 was reconstructed respectively.The established model was imported into 3-Matic software in the format of"Stl"to reconstruct the intervertebral disc,and the fibrous intervertebral disc model was obtained.The improved model was further imported into Hypermesh software,and the vertebra,nucleus pulposus,annulus fibrosus and ligament were mesh-divided.After the material properties were given,the model was imported into ABAQUS software to observe the range of motion of each vertebral body in seven different working conditions of T11-S1,and analyze the biomechanical characteristics of each segment of annulus fibrosus and nucleus pulposus. RESULTS AND CONCLUSION:(1)The range of motion of L1 vertebrae was higher than that of other vertebrae under six different working conditions:extension,forward flexion,rotation(left and right),and lateral flexion(left and right).The maximum range of motion was 2.18° during L1 vertebral flexion,and the minimum range of motion was 0.12° during L5 vertebral extension.(2)The annular fiber flexion at L2-L3 segments was greater than the extension(P<0.05),and the annular fiber flexion at L3-L4 and L4-L5 segments was less than the extension(P<0.05).The left rotation of L1-L2 annular fibers was greater than the right rotation(P<0.05).The left flexion of the annulus was greater than the right flexion in L1-L2,L2-L3,L3-L4,L4-L5 and L5-S1 segments(P<0.05).(3)The nucleus pulposus stresses of T11-L12,L1-L2,L2-L3,L3-L4 and L4-L5 segments in forward flexion were greater than in extension(P<0.05).The left rotation of T12-L1 and L3-L4 segments was smaller than the right rotation(P<0.05),and that of T11-T12,L1-L2,and L2-L3 segments was larger than the right rotation(P<0.05).The left flexion was larger than the right flexion in the T11-S1 segment.(4)It is concluded that in ankylosing spondylitis patients with lumbar kyphosis,the minimum range of motion of the vertebral body is located at the L5 vertebral body in extension.To prevent fractures,it is recommended to avoid exercise in the extension position.During the onset of lumbar kyphosis in patients with ankylosing spondylitis,the maximum stress of the annulus fibrosus and nucleus pulposus is located in the L1-L2 segment,which is fixed and will not alter with the change of body position.The late surgical treatment and correction of deformity should focus on releasing the pressure of the annulus fibrosus and nucleus pulposus in this segment to avoid the rupture of the annulus fibrosus and the injury of the nucleus pulposus.

BACKGROUND:Ankylosing spondylitis is a progressive inflammation of spinal stiffness deformity caused by tissue ossification and fibrosis.The posture of ankylosing spondylitis patients is abnormal and their activities are limited that minor injuries can lead to thoracolumbar fractures.Traditional medical image observation limits doctors'preoperative decision planning and postoperative disease prevention for ankylosing spondylitis treatment. OBJECTIVE:Based on the spinal model of ankylosing spondylitis patients before and after posterior spinal cancellous ossification osteotomy("Y"osteotomy for short),to explore the biomechanical changes of"Y"osteotomy and fixation in the treatment of ankylosing spondylitis. METHODS:Based on the preoperative and postoperative CT images of an ankylosing spondylitis patient who went to the Second Affiliated Hospital of Inner Mongolia Medical University,a three-dimensional spine model(T11-S1)before and after"Y"osteotomy(L3 osteotomy)was reconstructed in Mimics 19.0 software.A 7.5 Nm torque was applied to the top of T11 vertebral body to simulate the movement of the spine under six conditions:flexion,extension,left bending,right bending,left rotation and right rotation.Finally,the range of motion of each vertebral body,the stress of each intervertebral disc,and the stress of the screw rod system were simulated. RESULTS AND CONCLUSION:(1)After"Y"type osteotomy and posterior fixation,the range of motion of all vertebrae in the spine decreased,and the loss rate of upper vertebrae was large(L1:77.95%).(2)The maximum stress of the spinal intervertebral disc before operation occurred at the L1-L2 segment(0.55 MPa),and the maximum stress of the spinal intervertebral disc after operation occurred at the T11-T12 segment(0.50 MPa),and the stress of intervertebral disc below T12 was far less than that before operation.(3)The maximum stress of the screw rod system(166.67 MPa)occurred in the upper and middle segments of the rod body and the root of the pedicle screw.(4)In conclusion,the"Y"type posterior fixation operation enhances the stability of the spine and reduces the range of motion of the spine.The vertebral body decompression of the fixed segment is great and the stress-shielding phenomenon of the lower vertebral body is significant.The stiffness of the rod body and the stress concentration area of the pedicle screw should be strengthened to avoid the fracture of the rod caused by stress fatigue.

Objective:To detect the expression levels of various immune cells in peripheral blood,and to ex-plore their relationship with unexplained recurrent spontaneous abortion(URSA)and its clinical significance in di-agnosis and treatment.Methods:A total of 351 patients with URSA who visited Hebei Reproductive Health Hospi-tal between January 2020 and September 2022 were enrolled as the URSA group,while a control group compri-sing 30 healthy women who had experienced uncomplicated term delivery once and had no history of adverse pregnancy outcomes during the same period was selected.The levels of various immune cell subsets in peripheral blood during the luteal phase were measured and compared between the two groups.Receiver operating charac-teristic(ROC)curve analysis was performed to determine the optimal cutoff values of immune cell levels that could assist in URSA diagnosis and treatment,while logistic regression analysis was conducted to identify factors influ-encing URSA occurrence.Results:The number and percentage of CD3+CD8+cells in the peripheral blood of the URSA group were significantly lower compared to those in the control group(P＜0.05).Conversely,the per-centage of NK cells was significantly higher in the URSA group than in the control group(P＜0.05).Logistic re-gression analysis revealed that the increase in CD3+CD8+cell count in peripheral blood during the luteal phase was a protective factor of URSA(OR＜1,P＜0.05).ROC curve analysis determined optimal cutoff values for im-mune cell levels to assist in the diagnosing and treating URSA:702.82 cells/μl for CD3+CD8+cell count,28.39％for CD3+CD8+cell percentage,and 12.33％for NK cell percentage.After using the optimal cutoff value to convert continuous variables into binary variables,Logistic regression analysis showed that a CD3+CD8+cell count＜702.82 cells/μl and an NK cell percentage＞12.33％were independent risk factors for URSA(OR＞1,P＜0.05).Conclusions:The decrease of CD3+CD8+cells in peripheral blood during midluteal phase is closely related to the occurrence of URSA.The number of CD3+CD8+cells(702.82 cells/μl)and the percentage of NK cells(12.33％)can be used as reference values for the diagnosis and treatment of URSA.