Objective To retrospectively analyze the epidemiological trend of children with lower gastrointestinal bleeding in recent 10 years,and investigate the change of their disease burden,so as to provide a theoretical basis for the accurate prevention and control of children's lower gastrointestinal bleeding. Methods A total of 671 children with "lower gastrointestinal bleeding" who were diagnosed in our hospital from 2012 to 2021 were collected as research subjects. To analyze the microscopic examination rate and common etiology of lower gastrointestinal bleeding in children in the past 10 years,as well as the epidemiological characteristics of different age groups, different regions and different basic diseases; Calculate and compare the rate of disability life lost (YLD), early death life lost (YLL) and disability adjusted life year (DALY) of children with lower gastrointestinal bleeding within 10 years, and calculate the annual change percentage (AAPC) to analyze the change trend of disease burden. Results The microscopic examination rate of children with lower gastrointestinal bleeding showed a trend of increasing in the past 10 years (P<0.001). Among them, the most common causes are Crohn's disease, ulcerative colitis and chronic colitis. The proportion of children with lower gastrointestinal bleeding was higher in boys, >18 years old, hypertension and gastroenteritis. The DALY rate, YLL rate and YLD rate caused by lower gastrointestinal bleeding in the past 10 years showed an upward trend (P<0.05). Conclusion The microscopic examination rate of lower gastrointestinal bleeding in children was graduallyincreasing,and the prevalence rate of basic diseases such as boys,hypertension and gastroenteritis was increasing;in addition,the disease burden caused by children's lower gastrointestinal bleeding was also increasing year by year and should be protected.

Objective To analyze the incidence characteristics and pathogen epidemic characteristics of respiratory tract children in Chongqing Kaizhou area. Methods A total of 5 328 children admitted to our hospital from January 2019 to December 2022 were selected as the research subjects. Indirect immunofluorescence method was used to detect 8 common respiratory pathogens in the serum of the children; Using SPSS 22.0 software, analyze the incidence characteristics and pathogen prevalence of 8 pathogens in respiratory tract children. Results (1) The highest detection rate was MP (χ²=12.141, P<0.05); (2) The detection rate of PM and PIV in the infant group was lower than that in the infant group and large group, The difference was statistically significant (χ²=7.923, P<0.05); (3) Eight pathogens IgM had the highest detection rate in the spring, Opposite in winter (χ²=1.872, P<0.05); (4) A total of 3 817 IgM antibody positive cases were detected in 5328 sick infants, The positive rate was 71.64%, There was a statistical difference between the sexes (χ²=3.928, P<0.05). Conclusion The detection rate of respiratory pathogens varies in age and sex, which is highest in spring, so pay attention to the respiratory tract infection in spring, focusing on the prevention and treatment of mycoplasma pneumoniae.

Objective:To investigate the efficacy and adverse reactions of whole-lung low-dose radiotherapy (LDRT) in patients with severe/critical coronavirus disease 2019 (COVID-19).Methods:Eight patients with severe/critical COVID-19 treated in the Jiangyin Hospital Affiliated to Nantong University from January to June 2023 who were treated with whole-lung LDRT after deteriorating or failing to improve post-medical treatment were enrolled in this single-arm phase I clinical trial. They received anterior-posterior penetrating radiation in a supine or prone position, with a total dose range from 0.5 to 1.5 Gy and a dose weight ratio of 1∶1. The oxygenation status, inflammatory markers, and imaging changes before and after radiotherapy were analyzed, and patients were followed up for acute radiation-induced adverse reactions.Results:One week after LDRT, the SaO 2/FiO 2 or PaO 2/FiO 2 indices increased in seven patients (87.5%), inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) decreased in seven patients (87.5%), and chest CT/chest radiographs revealed a significant reduction in the extent of pneumonia involvement in 5 patients (62.5%). No evident acute radiation-related adverse reactions were observed. Conclusions:Whole-lung LDRT with a dose range from 0.5 to 1.5 Gy can reduce inflammatory markers, improve clinical symptoms, and promote inflammatory absorption in patients with severe/critical COVID-19 who responded poorly to medical treatment while not inducing acute adverse reactions.

Objective:To evaluate the difference in safety and immunogenicity of live rotavirus vaccine (oral) and measles, mumps and rubella (MMR) vaccine immunized alone or in combination.Methods:This study recruited 1 752 children aged 8-9 months who had not been vaccinated with live rotavirus vaccine (oral) or MMR vaccine after birth. The subjects were divided into three groups: study group (652 subjects, immunized with live rotavirus vaccine and MMR vaccine), control group 1 (723 subjects, immunized with live rotavirus vaccine) and control group 2 (377 subjects, immunized with MMR vaccine). Local and systemic adverse reactions within 30 d after vaccination were recorded. Serum samples were collected before and 35-42 d after immunization for analyzing the changes in antibodies.Results:Immunization alone or in combination with live rotavirus vaccine (oral) and MMR vaccine achieved similar results in the positive rates and concentrations of antibodies against rotavirus, measles and rubella viruses ( P>0.05). Moreover, the positive rates and the concentrations of the three antibodies were increased after vaccination. Compared with the control group 2, the concentration of antibody against mumps virus in the study group was increased ( P<0.05), but no significant difference in the positive rate of antibody against mumps virus was found between the two groups ( P>0.05). The positive rate and the concentration of antibody against mumps virus were increased after combined immunization or immunization with MMR vaccine alone. The overall incidence of fever and diarrhea was 1.54% (27/1 752) and 0.63% (11/1 752). No other abnormal reactions, incidental reactions or adverse reactions of any clinical significance were observed. Conclusions:Live rotavirus vaccine (oral) and MMR vaccine immunized alone or in combination showed good immunogenicity and safety.

Objective:To explore the short-term outcomes of reconstruction of tumorous critical bone defects at femoral shaft with a 3D printed ultra-short stem with a porous structure.Methods:From September 2016 to June 2018, 8 patients underwent reconstruction of critical bone defects with a 3D printed ultra-short stem with a porous structure after resection of femoral shaft malignant tumor at Department of Orthopaedics, West China Hospital. There were 4 males and 4 females, with an average age of 36.9 years (from 11 to 61 years). Their preoperative Enneking staging was stage Ⅱb in all. There were 3 osteosarcomas, 2 Ewing sarcomas, 2 chondrosarcomas and one periosteal osteosarcoma. Preoperative CT/MRI image fusion technology was used to define the surgical boundary, design the guide plate and prosthesis, and perform surgical simulation. Tomosynthesis-shimadzu Metal Artefact Reduction technology was used to evaluate osseointegration. Complications and bone oncology prognosis of the patients were documented. The lower limb function of the patients was evaluated using Musculoskeletal Tumor Society (MSTS) 1993 scoring and knee range of motion.Results:The overall follow-up time ranged from 36 to 50 months, averaging 42.8 months. During operation one patient sustained a periprosthesis fracture, the union of which was followed up after wire assisted fixation. There was no local tumor recurrence, lung metastasis or death. The last follow-up revealed good osseointegration and basically isometric lower extremities in all cases. There was no such a complication as aseptic loosening of the prosthesis, deep infection or prosthesis fracture during the follow-up period. At the last follow-up in the 8 patients, the flexion range of the knee joint was 116.2°±9.1°, significantly improved compared with that before operation (98.8°±10.9°), and the MSTS score was (26.2±2.1) points, also significantly improved compared with that before operation [(21.6±1.8) points] ( P<0.05). Conclusions:Reconstruction with a 3D printed ultra-short stem with a porous structure is an accurate operation for femoral shaft tumorous bone defects. With careful preoperative design, intraoperative manipulation and strict postoperative follow-up management, this operation can lead to fine early curative outcomes for long shaft critical bone defects.

Objective:To determine hydrazine quantitatively in workplace air by gas chromatography with large bore capillary column.Methods:In October 2019, hydrazine in the air was adsorbed by acid silica gel tube sampling and desorped using sulfuric acid solution. After derivatization with furfural and extraction, the content of hydrazine was determined by DM-FFAP capillary column gas chromatography with flame ionization detector.Results:The linear regression equation was y=353.8 x+21.2 ( r=0.9998) between 0.1-2.0 μg/ml of target concentration. The detection limit was 0.030 μg/ml. The lower limit of quantification was 0.100 μg/ml. If 15 L air sample was collected, the minimum detection concentration was 0.004 mg/m 3 and the minimum quantitative concentration was 0.013 mg/m 3 respectively. The average desorption efficiency was 86.5%-89.4%. The recovery was 94.4%-97.1%. The relative standard deviation was 1.6%-4.9%. Hydrazine and furfural derivative was 2-furaldehyde hydrazine. Conclusion:The method has symmetrical peak shape of hydrazine derivatives chromatographic peaks, short analysis time, easy operation, and is suitable for the determination of the concentration of hydrazine in the air in the workplace.

【Objective】 To establish a predictive model for patients with hemorrhage after CT-guided coaxial core needle lung biopsy （CCNB） based on logistic regression. 【Methods】 A total of 489 patients who had undergone CCNB were retrospectively recruited. The potential risk factors of hemorrhage after lung biopsy were analyzed by univariate and multivariate logistic regression， through which we screened the independent risk factors and established a prediction model for hemorrhage. We evaluated the discrimination， calibration and clinical usefulness of the model. 【Results】 There were 141 cases （42.6%） of hemorrhage in the development group and 66 cases （41.8%） of hemorrhage in the validation group； there was no case of severe hemorrhage or hemothorax. Multivariate logistic regression analysis showed that fibrinogen degradation products， pulmonary interstitial fibrosis， largest diameter and puncture depth were independent predictive factors of hemorrhage. Hemorrhage prediction model was established and presented in the form of a nomogram. Discrimination of the model： the AUC was 0.837 in the development group and 0.777 in the validation group. The calibration curve showed good agreement between predicted probability and actual probability of hemorrhage. The unreliability test yielded a P value of 0.849 in the development group and 0.147 in the validation group. The DCA curve showed that the hemorrhage predictive model could increase the benefit of patients. 【Conclusion】 The predictive model of hemorrhage in patients after CCNB based on logistic regression can be used in clinical practice.

Objective:To determine hydrazine quantitatively in workplace air by gas chromatography with large bore capillary column.Methods:In October 2019, hydrazine in the air was adsorbed by acid silica gel tube sampling and desorped using sulfuric acid solution. After derivatization with furfural and extraction, the content of hydrazine was determined by DM-FFAP capillary column gas chromatography with flame ionization detector.Results:The linear regression equation was y=353.8 x+21.2 ( r=0.9998) between 0.1-2.0 μg/ml of target concentration. The detection limit was 0.030 μg/ml. The lower limit of quantification was 0.100 μg/ml. If 15 L air sample was collected, the minimum detection concentration was 0.004 mg/m 3 and the minimum quantitative concentration was 0.013 mg/m 3 respectively. The average desorption efficiency was 86.5%-89.4%. The recovery was 94.4%-97.1%. The relative standard deviation was 1.6%-4.9%. Hydrazine and furfural derivative was 2-furaldehyde hydrazine. Conclusion:The method has symmetrical peak shape of hydrazine derivatives chromatographic peaks, short analysis time, easy operation, and is suitable for the determination of the concentration of hydrazine in the air in the workplace.

Objective:To investigate the immunogenicity and safety of a boost dose of measles, mumps, and rubella combined vaccine (MMR) for children 4 to 6 years old.Methods:Children, aged 4 to 6 years old, had vaccinated with 1 dose of measles and rubella combined vaccine(MR) at the age of 8 months and 1 dose of MMR vaccine at 18-months, were recruited in Shanxi, Inner Mongolia, and Beijing, respectively. All children were assigned into 4, 5 and 6-year-old group. The children who met inclusion and exclusion criteria were vaccinated with 1 dose MMR vaccine, and were collected blood samples before vaccination and 35 to 42 d after the vaccination. During the study period, adverse events were collected at 30 min, 1 d, 2 d, 3 d, 4-12 d, and 13 to 42 days after vaccination. Serum was tested for IgG antibodies against measles, mumps and rubella. Geometric mean concentrations (GMC) of measles, mumps, and rubella antibodies were compared among groups by analysis of variance or non-parametric test. Seropositive rates and adverse event rates were compared among groups by Chi-square test or Fisher exact test.Results:A total of 500 children were included in immunogenicity analysis and 535 children were included in safety analysis. The overall adverse event rate was 20.37%, the most of severity for adverse events was mild. The rates of local and systemic adverse events were 0.37% and 20.00%, respectively. Symptoms of local adverse events were redness. The main systemic adverse events were fever, followed by cough, rash and runny nose. Received a dose of MMR vaccine for booster immunization, the seropositive rates of measles antibody, mumps antibody and rubella antibody were above 99% for all 3 age groups, and there was no significant difference between groups. There were significant differences in mumps antibody GMC among groups ( P=0.042), but no significant differences in measles and rubella antibodies GMC. Conclusion:The immunogenicity and safety of a boosted MMR vaccintion in children aged 4, 5 and 6 years were all similar good.

Objective To evaluate the safety of a Chinese thimerosal-free trivalent split influenza virus vaccine after being marketed in a large population. Methods Through the information management system of adverse event following immunization (AEFI), the adverse events in healthy people aged 6 months and above who were vaccinated with split influenza virus vaccine in Hubei Province from October to December 2015 were collected. The data was analyzed by descriptive methodology. Results From October 1, 2015 to June 30, 2016, among the 227 920 people in Hubei Province who were vaccinated with split influenza virus vaccine, the common adverse reactions were mainly fever, redness, irritability, pain and itching. Four cases of AEFI were passively observed and reported in the system, with a reporting rate of 1.76/100 000, among which 3 cases were anaphylactic rash and 1 case was optic neuritis. Conclusion The Chinese thimerosal-free trivalent split influenza virus vaccine used in Hubei Province had a good safety record and is suitable for the general vaccination of people without vaccination contraindications.