BACKGROUND:Mesenchymal stem cells show extremely therapeutic potential for radiation-induced lung injury through delivering exosomes.Age is a primary factor affecting the function and biological efficacy of mesenchymal stem cells.OBJECTIVE:To investigate the protective effects of exosomes derived from bone marrow mesenchymal stem cells of different mouse ages on radiation-induced lung injury in mice.METHODS:Bone marrow mesenchymal stem cells of young mice and old mice were obtained by whole bone marrow adherent culture.The exosomes were isolated from the supernatant of passage 3 bone marrow mesenchymal stem cells.Ten 2-month-old C57BL/6J mice were randomly selected as the control group after anesthesia and not irradiated.The remaining 30 2-month-old C57BL/6J mice were used to establish a mouse radiation-induced lung injury model and were randomly divided into three groups.Exosomes derived from bone marrow mesenchymal stem cells of young mice,exosomes derived from bone marrow mesenchymal stem cells of old mice,and PBS were injected through the tail vein,respectively.The survival rate of mice was monitored.The lung function,lung inflammation and fibrosis were assessed at 1 and 12 weeks after irradiation.RESULTS AND CONCLUSION:(1)The concentrations of particles and proteins in exosomes derived from bone marrow mesenchymal stem cells of young mice were higher than those in exosomes derived from bone marrow mesenchymal stem cells of old mice.(2)Compared with the control group,the survival rate of mice in the PBS group was low,and lung inflammation was obvious at week 1 after irradiation,and the levels and mRNA expressions of interleukin-1β,interleukin-6,and tumor necrosis factor-α were increased.Collagen deposition in lung tissues was observed at week 12 after irradiation,and the mRNA level of E-cadherin was decreased,while the mRNA levels of α-smooth muscle actin,transforming growth factor-β1,and β-catenin were increased.(3)Compared with the PBS group,the survival rate of mice in the exosome group was significantly improved,and the level of proinflammatory factors and their mRNA expression were reduced at week 1 after irradiation,the mRNA level of E-cadherin was increased,and the mRNA levels of α-smooth muscle actin,transforming growth factor β1 and β-catenin were reduced at week 12 after irradiation.(4)Among all the above indicators,the therapeutic effect of exosomes derived from bone marrow mesenchymal stem cells of young mice was better than that of exosomes derived from bone marrow mesenchymal stem cells of old mice.(5)The results showed that exosomes derived from bone marrow mesenchymal stem cells of young mice contained more particles and proteins,and the effect of alleviating early inflammation and late fibrosis of radiation-induced lung injury in mice was better than that of exosomes derived from bone marrow mesenchymal stem cells of old mice.

BACKGROUND:Chitosan has a place in the biomedical field due to its good biological properties and unique physicochemical properties,especially in tissue engineering and drug delivery with good application prospects.OBJECTIVE:To summarize the research progress of the role of chitosan in the repair and regeneration of oral soft and hard tissues.METHODS:A computerized search of CNKI and PubMed databases was performed with the search terms"chitosan,oral mucosal diseases,periodontal diseases,tissue regeneration,bacteriostatic,drug carrier,wound healing"in Chinese and English.The search time limit was from 2010 to 2024.After screening according to the inclusion and exclusion criteria,88 articles were finally included for summary analysis.RESULTS AND CONCLUSION:Chitosan is a promising biomaterial in bone and pulp regeneration as it has the ability to stimulate the recruitment and adhesion of osteogenic progenitor cells and dental pulp stem cells.Chitosan prevents caries,periodontal disease,and candidiasis by inhibiting Streptococcus pyogenes,Porphyromonas gingivalis,and Candida in the oral cavity.Chitosan nanocomposites have higher stability,better biocompatibility,and slow-release properties of drugs and can be enhanced by combining with other chemical reagents to enhance their anticancer properties.Chitosan possesses drug delivery,antibacterial activity,hemostasis and wound healing,which in turn can block the erosion of wounds by saliva and oral flora,relieve pain,repair and promote wound healing.Chitosan promotes the deposition of calcified material,which is conducive to the remineralisation of enamel and dentin.

BACKGROUND:Mesenchymal stem cells show extremely therapeutic potential for radiation-induced lung injury through delivering exosomes.Age is a primary factor affecting the function and biological efficacy of mesenchymal stem cells.OBJECTIVE:To investigate the protective effects of exosomes derived from bone marrow mesenchymal stem cells of different mouse ages on radiation-induced lung injury in mice.METHODS:Bone marrow mesenchymal stem cells of young mice and old mice were obtained by whole bone marrow adherent culture.The exosomes were isolated from the supernatant of passage 3 bone marrow mesenchymal stem cells.Ten 2-month-old C57BL/6J mice were randomly selected as the control group after anesthesia and not irradiated.The remaining 30 2-month-old C57BL/6J mice were used to establish a mouse radiation-induced lung injury model and were randomly divided into three groups.Exosomes derived from bone marrow mesenchymal stem cells of young mice,exosomes derived from bone marrow mesenchymal stem cells of old mice,and PBS were injected through the tail vein,respectively.The survival rate of mice was monitored.The lung function,lung inflammation and fibrosis were assessed at 1 and 12 weeks after irradiation.RESULTS AND CONCLUSION:(1)The concentrations of particles and proteins in exosomes derived from bone marrow mesenchymal stem cells of young mice were higher than those in exosomes derived from bone marrow mesenchymal stem cells of old mice.(2)Compared with the control group,the survival rate of mice in the PBS group was low,and lung inflammation was obvious at week 1 after irradiation,and the levels and mRNA expressions of interleukin-1β,interleukin-6,and tumor necrosis factor-α were increased.Collagen deposition in lung tissues was observed at week 12 after irradiation,and the mRNA level of E-cadherin was decreased,while the mRNA levels of α-smooth muscle actin,transforming growth factor-β1,and β-catenin were increased.(3)Compared with the PBS group,the survival rate of mice in the exosome group was significantly improved,and the level of proinflammatory factors and their mRNA expression were reduced at week 1 after irradiation,the mRNA level of E-cadherin was increased,and the mRNA levels of α-smooth muscle actin,transforming growth factor β1 and β-catenin were reduced at week 12 after irradiation.(4)Among all the above indicators,the therapeutic effect of exosomes derived from bone marrow mesenchymal stem cells of young mice was better than that of exosomes derived from bone marrow mesenchymal stem cells of old mice.(5)The results showed that exosomes derived from bone marrow mesenchymal stem cells of young mice contained more particles and proteins,and the effect of alleviating early inflammation and late fibrosis of radiation-induced lung injury in mice was better than that of exosomes derived from bone marrow mesenchymal stem cells of old mice.

BACKGROUND:Chitosan has a place in the biomedical field due to its good biological properties and unique physicochemical properties,especially in tissue engineering and drug delivery with good application prospects.OBJECTIVE:To summarize the research progress of the role of chitosan in the repair and regeneration of oral soft and hard tissues.METHODS:A computerized search of CNKI and PubMed databases was performed with the search terms"chitosan,oral mucosal diseases,periodontal diseases,tissue regeneration,bacteriostatic,drug carrier,wound healing"in Chinese and English.The search time limit was from 2010 to 2024.After screening according to the inclusion and exclusion criteria,88 articles were finally included for summary analysis.RESULTS AND CONCLUSION:Chitosan is a promising biomaterial in bone and pulp regeneration as it has the ability to stimulate the recruitment and adhesion of osteogenic progenitor cells and dental pulp stem cells.Chitosan prevents caries,periodontal disease,and candidiasis by inhibiting Streptococcus pyogenes,Porphyromonas gingivalis,and Candida in the oral cavity.Chitosan nanocomposites have higher stability,better biocompatibility,and slow-release properties of drugs and can be enhanced by combining with other chemical reagents to enhance their anticancer properties.Chitosan possesses drug delivery,antibacterial activity,hemostasis and wound healing,which in turn can block the erosion of wounds by saliva and oral flora,relieve pain,repair and promote wound healing.Chitosan promotes the deposition of calcified material,which is conducive to the remineralisation of enamel and dentin.

Objective: To investigate the association between screening detected myopia in primary school students and mixed exposure to air pollutants, so as to provide a scientific basis for the prevention and control of myopia in children and adolescents. Methods: From May to July 2023, a cluster random sampling method was used to select 15 102 primary school students in grades 3 through 6 from Hefei, Zhongshan, Shenyang, and Nanchang citys. Data were collected through questionnaires, distance vision screening, and computerized refraction. Monthly average concentration data for particulate matter (PM 10 ), fine particulate matter (PM 2. 5), NO 2 and SO 2 were used to calculate the annual average pollutant concentrations for primary school students. Quantile g computation model was employed to analyze the association between mixed exposure to air pollutants and screening detected myopia. Results: The differences in concentrations of the four pollutants among cities were statistically significant ( H =12 886.0, 13 285.0, 8 559.0, 13 181.0, all P <0.01). In the overall sample, there was no statistically significant association between combined exposure to air pollutants and the risk of myopia ( β=0.033, 95%CI=-0.004-0.072, P =0.08). Stratified analysis by outdoor activity time showed that among primary school students with outdoor activity time ≤1 h/d, mixed exposure to air pollutants was positively associated with the risk of myopia ( β=0.050, 95%CI=0.002-0.099, P =0.04); after stratification by city, combined exposure to air pollutants was significantly associated with the risk of myopia among primary school students in Nanchang and Shenyang [ β (95% CI )= 0.232(0.175-0.289), 0.080(0.006-0.155), both P <0.05], whereas no statistically significant association was observed among primary school students in Hefei and Zhongshan [ β (95% CI )=-0.010(-0.071-0.051), -0.032(-0.167-0.102), both P ＞ 0.05 ]. Conclusions Exposure to multiple air pollutants may increase the risk of myopia in primary school students, with the risk influenced by time spent outdoors and geographical location. It is recommended that outdoor activity management for children be strengthened in areas with higher air pollution levels, and that environmental factors be incorporated into comprehensive myopia prevention and control strategies.

Objective: To investigate the relationship between physical development indicators and the onset and progression of myopia among children and adolescents, so as to provide theoretical support for coordinated vision and physical health management. Methods: A prospective cohort study was conducted. In September 2022, 3 102 students from grade one in primary school to grade three in junior high school (five year primary school and four year junior high school) from six schools in Huantai County, Shandong Province, were selected using multistage cluster random sampling method to participate in an epidemiological survey on myopia, with follow up completed in September 2023. Follow up value minus baseline value( d ) was used to assess changes in physical development and vision indicators. Multivariate Logistic regression analysis was used to examine the relationship between physical development indicators and the incidence of myopia. Generalized linear models were established to analyze the relationship between physical development indicators and changes in d spherical equivalent (SE) and d axial length (AL) . Results: Multivariate Logistic regression analysis showed that, after adjusting for factors such as gender, age, and baseline body mass index, the third ( Q 3)and fourth ( Q 4)quartiles of d height showed increased risks of myopia onset within one year compared to the first quartile( Q 1) ( OR =1.85,95% CI =1.18-2.88; OR =1.74,95% CI =1.09-2.78,both P ＜0.05). Results from the generalized linear model indicated that, after adjusting for confounding factors such as gender, age, and baseline SE, d SE was negatively correlated with d height and d weight in children and adolescents ( β =-0.024, 95% CI =-0.031 to -0.018; β =-0.006, 95% CI =-0.011 to -0.001), d AL was positively correlated with d height and d weight in children and adolescents ( β =0.011, 95% CI =0.008-0.013; β =0.005, 95% CI =0.003-0.007) (all P ＜0.05). Conclusions Physical development indicators in children and adolescents were associated with the onset and progression of myopia. Dynamic monitoring and early intervention of myopia should be strengthened for children and adolescents with rapid height and weight gain to achieve coordinated management of myopia and physical development.

Objective: To analyze the epidemiological characteristics of varicella among nursery children in Shenzhen from 2015 to 2024, and to evaluate the impact of optimizing varicella vaccine (VarV) immunization strategies on varicella incidence. Methods: Varicella incidence data for nursery children in Shenzhen from 2015 to 2024 were obtained from the China Disease Prevention and Control Information System. The study period was divided into three phases:one dose self pay VarV (January 2015 to October 2017), two dose self pay VarV (November 2017 to October 2019), and two dose free VarV (November 2019 to December 2024). Interrupted time series (ITS) analysis was conducted to assess changes in the level and trend of varicella incidence associated with each phase of policy implementation. Results: A total of 27 517 varicella cases was reported among nursery children from 2015 to 2024, with an average annual incidence of 514.01/100 000. During the same period, 136 clustered outbreaks were reported in nursery institutions, involving a cumulative total of 1 091 cases. ITS analysis showed that during the self pay 1 dose stage, the varicella incidence among nursery children showed an upward trend, with an average monthly increase of 2.58/100 000 (95% CI =2.21/ 100 000 -2.95/100 000, P <0.01). After the implementation of the self pay 2 dose strategy, the incidence decreased, with a change in incidence of -26.12/100 000 (95% CI =-37.30/100 000 to -14.94/100 000) and a change in slope of -2.65/100 000 (95% CI = -3.38/100 000 to -1.93/100 000)(all P <0.01). After the implementation of the free 2 dose strategy, the incidence decreased further, with a change in incidence of -40.03/100 000 (95% CI =-50.39/100 000 to -29.66/100 000, P <0.01) and a change in slope of -0.56/100 000 (95% CI =-1.20/100 000-0.08/100 000, P =0.09). Conclusion The gradual optimization of the VarV vaccination strategy in Shenzhen from self pay 1 dose to free 2 dose has significantly reduced the varicella incidence among nursery children, demonstrating good short term control and long term intervention effectiveness.

ObjectiveTo investigate the epidemiological and clinical characteristics of human bocavirus (HBoV) in hospitalized children with acute lower respiratory tract infection (ALRTI) at a single-center children’s hospital in Shanghai, thereby providing evidence for the diagnosis, treatment, and prevention of HBoV infection. MethodsA retrospective study was conducted on 19 537 hospitalized children with ALRTI at Shanghai Children’s Hospital from January 2021 to December 2023. Multiplex polymerase chain reaction (PCR) combined with capillary electrophoresis was used to detect HBoV and 12 other common respiratory viruses /atypical pathogens. The positive detection rate, demographic characteristics (sex, age), temporal distribution (year, season) of HBoV, as well as the clinical characteristics of severe and non-severe pneumonia were analyzed. ResultsThe overall HBoV-positive rate was 2.57% (503/19 537), with 59.44% (299/503) being single infections and 40.56% (204/503) being co-infections. The positive detection rate was significantly higher in boys than that in girls (2.78% vs 2.33%, χ²=3.88, P=0.049). The highest infection rate was observed in toddlers, followed by infants (χ²=379.57, P<0.001). The positive rate peaked in 2021 and reached its lowest point in 2023 (χ²=45.49, P<0.001), with epidemics mainly prevalent in summer and autumn. The main clinical symptoms were cough (90.06%, 453/503), fever (75.94%, 382/503), and wheezing (39.96%, 201/503). Children with severe pneumonia showed a higher incidence of wheezing compared with the non-severe group (P<0.001), while underlying diseases and co-infections had no significant association with disease severity (P>0.05). ConclusionHBoV was an important pathogen of ALRTI in children, predominantly affecting infants and toddlers, with higher susceptibility in boys and seasonal peaks in autumn and summer. The main clinical manifestations included cough, fever, and wheezing, with wheezing being more prevalent in children with severe pneumonia.

ObjectiveTo explore the 28-day mortality risk of Klebsiella pneumoniae (KP) bloodstream infections (BSI) and its related influencing factors, thereby providing a scientific basis for the effective control of KP-BSI and improvement of patient prognosis. MethodsFrom January 2018 to December 2024, a retrospective review was conducted on hospitalized patients aged >18 years old treated for KP-BSI at a tertiary hospital in Hangzhou. Logistic and Cox regression analyses were performed to identify the epidemiological characteristics and the risk factors for the 28-day mortality associated with KP-BSI. ResultsA total of 123 patients with KP-BSI were included in this study, comprising 64 cases infected with carbapenem-resistant Klebsiella pneumoniae (CRKP) and 59 cases infected with carbapenem-susceptible Klebsiella pneumoniae (CSKP). Compared with CSKP-BSI, patients with CRKP-BSI more frequently presented with chronic pulmonary disease (χ²=4.29, P=0.038), concomitant infections at other sites (χ²=10.90, P=0.001), and a higher frequency of invasive procedures prior to infection (central venous catheterization, mechanical ventilation, and indwelling urinary catheter), as well as glucocorticoid use, hemodialysis, and blood transfusion (all P<0.05). The 28-day mortality was significantly higher in BSI cases caused by CRKP compared to that caused by CSKP (37.50% vs 5.08%, P<0.001). Cox regression analyses revealed that carbapenem resistance (HR=6.67, 95%CI: 1.48‒30.08, P=0.014) and blood transfusion (HR=3.58, 95%CI: 1.15‒11.19, P=0.028) were risk factors for the 28-day mortality in KP-BSI, while removal of central venous catheters after infection (HR=0.24, 95%CI: 0.08‒0.67, P=0.006) was associated with a reduced risk for the 28-day mortality. ConclusionCarbapenem resistance is associated with mortality outcomes in patients with KP-BSI. Strengthening infection control measures targeting the identified risk factors for CRKP-BSI may improve patient prognosis.

ObjectiveTo investigate the ability of clinically isolated， Helicobacter pylori （H. pylori）-specific gene polymerase chain reaction （PCR）-positive gastric， vaginal， and fecal Candida to release H. pylori. MethodsResuscitate 4 strains of H. pylori -specific 16S rDNA and ureA gene PCR-positive Candida strains isolated in laboratory from clinical sources， including 1 strain of gastric Candida， 1 strain of fecal Candida， 2 strains of vaginal Candida and the standard Candida albicans strain ATCC10231 （Ca10231）. The presence of H. pylori-specific ureA in the 5 strains of Candida isolates was confirmed by PCR. The aforementioned strains of Candida and H.pylori were inoculated into urea medium and cultured in a constant temperature incubator at 37 ℃. The color change of the medium was observed daily. A change in the medium's color from yellow to red indicated the presence of urease activity. Then， the five strains of Candida and H. pylori were co-incubated with the magnetic beads coated with H. pylori antibodies respectively. Scanning electron microscopy （SEM） was employed to observe the presence of bacilli adsorbed on the surface of the magnetic beads. PCR was used to detect the presence of H.pylori-specific 16S rDNA and ureA genes on magnetic beads. ResultsThe PCR analysis of the ureA gene in the four Candida isolates was positive， whereas the Ca10231 strain tested negative. Upon culturing the four Candida isolates on urea medium， the medium color changed from yellow to red which was determined to be urease positive， while the medium containing Ca10231 remained unchanged， which was urease negative. SEM revealed that bacilli could be observed on the surface of magnetic beads co-incubated with the 4 strains of Candida of clinical origin and H.pylori isolate. Specifically， PCR testing of the magnetic beads co-incubated with one vaginal Candida， one gastric Candida and H.pylori isolate showed positive results for the 16S rDNA and ureA genes of H. pylori； however， the PCR tests for the two genes were negative for the magnetic beads co-incubated with the other two Candida isolate. ConclusionThis study demonstrates that H. pylori-specific genes Candida can release H. pylori.