Objective:To investigate the role of human dermal microvascular endothelial cells(HMEC-1)exosome hsa-miR-4488_L in regulating the osteogenic and lipogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)and to elucidate the mechanism of action underlying fate differentiation.Methods:The hsa-miR-4488_L mimic or negative control mimic was transfected into BMSCs, which were then cultured under osteogenic or lipogenic conditions, respectively.RT-qPCR was employed to detect the mRNA expression levels of osteogenic and lipogenic genes in BMSCs.Alizarin red staining was utilized to assess the osteogenic differentiation capability of hsa-miR-4488_L in BMSCs, while oil red O staining was used to evaluate the lipogenic differentiation potential of BMSCs.The mimic control and hsa-miR-4488_L mimic were transfected into elderly BMSCs, and age-related phenotypes were assessed using RT-qPCR and SA-β-gal staining.The direct target genes of hsa-miR-4488_L acting on BMSCs were identified through bioinformatics analysis and subsequently validated by RT-qPCR and Western blot.Results:After treatment with the hsa-miR-4488_L mimic, the expressions of osteogenic-related genes ALP( P=0.007), BSP( P=0.001), and Col1( P<0.001)in BMSCs were upregulated.Additionally, alizarin red staining results indicated an increase in the number of calcified nodules Pparγ( P=0.002).Concurrently, under adipogenic induction conditions, the adipogenic-related genes Pparγ( P=0.008)and Perilipin( P<0.001)were significantly downregulated in the hsa-miR-4488_L mimic treatment group, and oil red O staining demonstrated a reduction in lipid droplet production( P=0.032).The mRNA expression of the aging-related gene P16( P=0.009)was downregulated following treatment with the hsa-miR-4488_L mimic, and the number of senescent cells decreased as indicated by SA-β-gal staining.Bioinformatics analysis revealed that Smad3 was the direct target gene of hsa-miR-4488_L in BMSCs.RT-qPCR results confirmed that the expression of Smad3 was downregulated after treatment with the hsa-miR-4488_L mimic( P=0.040).Furthermore, Western blot analysis showed a reduction in the protein level of Smad3. Conclusions:HMEC-EXOs-derived hsa-miR-4488_L regulates the balance between osteogenic and adipogenic differentiation in BMSCs through Smad3.Consequently, hsa-miR-4488_L may serve as a potential miRNA biomarker for age-related osteoporosis.

Objective To explore the integrating modeling strategy of prognosis prediction models,and provide support for the methodological selection of establishing effective clinical prediction models.Methods Based on the SEER liver cancer clinical follow-up data,the predictive performance and estimation accuracy of the classical Cox proportional hazard regression model,frequentist model averaging,and Bayesian model averaging methods were compared,and the applicability of model averaging methods was explored.Simulated studies were used to investigate the predictive performance of the models.Results Results of simulation analysis:the C index obtained by Bayesian model averaging was slightly higher than the Cox regression and frequentist model averaging.The 95%confidence interval of the C index tended to become narrower as the sample size increased.For variables with larger effect sizes,the Bayesian model averaging method obtained the smallest deviation of regression coefficients and the largest 95%interval coverage.Results of the case study:the validation set C index obtained by Cox regression,Bayesian model averaging and frequentist model averaging were 0.7845(95%CI:0.7613～0.8076),0.7851(95%CI:0.7619～0.8083)and 0.7845(95%CI:0.7613～0.8076),respectively.Conclusion Bayesian model averaging method can improve the ability of predicting prognosis when the sample size is small and the predictor variables are correlated.

Objective To investigate the effectiveness of the curriculum design and teaching mode reform in Health Statistics through the assessment by postgraduate students so as to enhance the teaching performance of the course.Methods A questionnaire survey was conducted among the postgraduate students of grade 2023 at a certain medical university.The survey covered such aspects as students'mastery and application of the course learning content,their evaluation and satisfaction with the course,etc.Descriptive approaches were employed to analyze and summarize the data.Results Students achieved a good command of theoretical knowledge and its application.They highly evaluated the teacher,the course content and its practicality,demonstrated a strong interest in learning,expressed a high level of satisfaction with the course,and manifested a strong willingness to continue studying the course.The learning of the course met the expectations of the students.The final exam scores in the later stage of curriculum reform(78.60±10.58)was higher than that before the reform(75.78±7.97,P<0.05);the excellent rate after the reform was 53.6%,which was higher than the 33.5%before the reform(P<0.05).Conclusion The construction of a course system that integrates knowledge,skills the mixed teaching mode of case-based teaching and the combination of theory and statistical software package operation are beneficial for enhancing postgraduate students'learning and application of the course in health statistics.It also strengthens the design and training of course application aspects for students in clinical medicine and dental medicine disciplines.

Objective To explore the integrating modeling strategy of prognosis prediction models,and provide support for the methodological selection of establishing effective clinical prediction models.Methods Based on the SEER liver cancer clinical follow-up data,the predictive performance and estimation accuracy of the classical Cox proportional hazard regression model,frequentist model averaging,and Bayesian model averaging methods were compared,and the applicability of model averaging methods was explored.Simulated studies were used to investigate the predictive performance of the models.Results Results of simulation analysis:the C index obtained by Bayesian model averaging was slightly higher than the Cox regression and frequentist model averaging.The 95%confidence interval of the C index tended to become narrower as the sample size increased.For variables with larger effect sizes,the Bayesian model averaging method obtained the smallest deviation of regression coefficients and the largest 95%interval coverage.Results of the case study:the validation set C index obtained by Cox regression,Bayesian model averaging and frequentist model averaging were 0.7845(95%CI:0.7613～0.8076),0.7851(95%CI:0.7619～0.8083)and 0.7845(95%CI:0.7613～0.8076),respectively.Conclusion Bayesian model averaging method can improve the ability of predicting prognosis when the sample size is small and the predictor variables are correlated.

Objective:To investigate the role of human dermal microvascular endothelial cells(HMEC-1)exosome hsa-miR-4488_L in regulating the osteogenic and lipogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)and to elucidate the mechanism of action underlying fate differentiation.Methods:The hsa-miR-4488_L mimic or negative control mimic was transfected into BMSCs, which were then cultured under osteogenic or lipogenic conditions, respectively.RT-qPCR was employed to detect the mRNA expression levels of osteogenic and lipogenic genes in BMSCs.Alizarin red staining was utilized to assess the osteogenic differentiation capability of hsa-miR-4488_L in BMSCs, while oil red O staining was used to evaluate the lipogenic differentiation potential of BMSCs.The mimic control and hsa-miR-4488_L mimic were transfected into elderly BMSCs, and age-related phenotypes were assessed using RT-qPCR and SA-β-gal staining.The direct target genes of hsa-miR-4488_L acting on BMSCs were identified through bioinformatics analysis and subsequently validated by RT-qPCR and Western blot.Results:After treatment with the hsa-miR-4488_L mimic, the expressions of osteogenic-related genes ALP( P=0.007), BSP( P=0.001), and Col1( P<0.001)in BMSCs were upregulated.Additionally, alizarin red staining results indicated an increase in the number of calcified nodules Pparγ( P=0.002).Concurrently, under adipogenic induction conditions, the adipogenic-related genes Pparγ( P=0.008)and Perilipin( P<0.001)were significantly downregulated in the hsa-miR-4488_L mimic treatment group, and oil red O staining demonstrated a reduction in lipid droplet production( P=0.032).The mRNA expression of the aging-related gene P16( P=0.009)was downregulated following treatment with the hsa-miR-4488_L mimic, and the number of senescent cells decreased as indicated by SA-β-gal staining.Bioinformatics analysis revealed that Smad3 was the direct target gene of hsa-miR-4488_L in BMSCs.RT-qPCR results confirmed that the expression of Smad3 was downregulated after treatment with the hsa-miR-4488_L mimic( P=0.040).Furthermore, Western blot analysis showed a reduction in the protein level of Smad3. Conclusions:HMEC-EXOs-derived hsa-miR-4488_L regulates the balance between osteogenic and adipogenic differentiation in BMSCs through Smad3.Consequently, hsa-miR-4488_L may serve as a potential miRNA biomarker for age-related osteoporosis.

Primary Sj?gren's syndrome(pSS)is a systemic autoimmune disease that is prevalent in middle-aged and elderly women,characterized by dry mouth,dry eyes,fatigue,and joint pain.Nearly one-third pSS patients have been suffering with osteoporosis(OP),displaying symptoms of lumbago,back pain,and even fracture,all of which severely affect their life quality.Common risk factors for pSS and OP include gender and age,persistent state of inflammation,immune disorders,intestinal flora imbalance,vitamin D deficiency,dyslipidemia and sarcopenia.Meanwhile,the comorbidities of pSS,such as renal tubular acidosis,primary biliary cholangitis,autoimmune thyroid diseases,and drugs(glucocorticoids,methotrexate,and cyclophosphamide)are unique risk factors for pSS complicated with OP.Education,guidance of healthy lifestyle,and OP screening are recommended for bone management of pSS patients.Early detection and intervention are crucial for keeping bone health and life quality in pSS patients.

Background The optimal model method for estimation of benchmark dose (BMD) does not consider the uncertainty of model selection. There is a lack of studies on using Bayesian model averaging (BMA) to estimate BMD. Objective To apply BMA to the exposure assessment of cadmium pollution in China, discuss the role of BMA in estimating BMD based on dose-response models, and to provide methodological support for health risk assessment of hazardous substances. Methods The parameters of five dose-response models (Gamma, Log-logistic, Log-probit, Two-stage, and Weibull models) estimated from the data from a cadmium-contaminated area in Baiyin City of Gansu Province and the urinary cadmium ranges in five cadmium-contaminated areas in China were used to simulate the data of varied correct models with different numbers of dosage groups (5 and 8) and different sample sizes (50, 100, and 200), then the performance of BMA and traditional optimal model were compared. The case analysis used the cadmium exposure data in Baiyin, Gansu Province. All analyses set urinary cadmium as the indicator of cadmium exposure, the abnormal rate of β₂-microglobulin as the effect indicator, and the benchmark response to 10%. The correct model (the model used when simulating data), optimal model [the model with smallest Akaike information criterion (AIC)], and BMA were used to estimate BMD and lower confidence limit of benchmark dose (BMDL); the BMDs, BMDLs, and relative deviations from different methods were compared. Results In the simulation study, with increasing sample size or the number of dosage groups, the intervals of the 5th percentile and the 90th percentile of BMD tended to be narrower; when the correct model was a single model, the relative deviation of BMD estimation by BMA was greater than that of the traditional optimal model; when the correct model was an equal weight mixed model, the relative deviation of BMD estimation by BMA was less than that by the traditional optimal model. For the data of cadmium-contaminated areas, the optimal model was a Log-probit model (AIC=1814.46), followed by a Log-logistic model (AIC=1814.57); the BMDs (BMDLs) estimated by the Log-probit model, the Log-logistic model, and BMA were 3.46 (2.68), 3.16 (2.33), and 2.92 (2.07) μg·g⁻¹, respectively. Conclusion The traditional optimal model is still recommended when the correct model is known. However, when the dose-response relationship of a hazardous substance is uncertain or with different sources or exposure grouping, compared with the traditional optimal model, BMA theoretically provides more stable estimation of BMD and BMDL by considering multiple possible alternative models.

Purpose To investigate the expression and significance of epiderma1 growth factor receptor( EGFR)mutation-specific anti-bodies in 1ung adenocarcinoma. Methods Immunohistochemica1( IHC)technique was used to detect the expression of EGFR muta-tion-specific antibodies(EGFR-19,EGFR-21)and EGFR tota1 protein antibody(EGFR-P)in 171 cases of 1ung adenocarcinoma with resected specimens,and EGFR gene mutation was a1so performed by amp1ification refractory mutation aystem-PCR( ARMS-PCR). The expression of EGFR-19,EGFR-21 and EGFR-P mutant proteins was compared with EGFR gene mutation and their re1ationship with histo1ogica1 c1assification and c1inica1 characteristics were ana1yzed. Results The expression of EGFR mutant protein was corre1ated with the poor differentiation group inc1uding micropapi11ary and so1id predominant types( P=0. 021 ). EGFR-21 high expression was re1ated to p1eura1 invasion(P=0. 005). The coherence of IHC(with EGFR-19/21 antibodies)and ARMS-PCR was existed(Kappa>0. 4 ). Taking ARMS-PCR as a standard,the sensitivity and specificity of EGFR-19 and EGFR-21 were 65. 0% and 89. 4%, 70. 0% and 97. 6%,respective1y. Conclusions Expression of EGFR mutation-specific antibodies is associated with poor differentia-tion and p1eura1 invasion. It suggests a worse prognosis indicator in 1ung adenocarcinoma. Because of the coherence with ARMS-PCR, using IHC with mutation-specific antibodies to detect the mutant proteins of EGFR-19/21 may act as a pre1iminary screening method of EGFR gene mutation.

PurposeTo evaluate the feasibility of a low-dose contrast medium protocol for 64-slice spiral CT angiography (CTA) of cerebral and carotid using a low-tube-voltage setting, and to compare the display effect of cerebral and carotid arteries by low-tube-voltage low-dose contrast medium and routine-tube-voltage routine-dose contrast medium scanning, and to assess the effect on radiation dose.Materials and MethodsEighty consecutive patients were prospectively selected to perform cerebral and carotid CTA inspection. The patients were randomly divided into control group and low dose group with 40 people in each group. The voltage in control group was 120 kV and the contrast agent was 80 ml; those in low dose group were 80 kV and 50 ml, respectively. The artery image quality was evaluated and venous interference was scored. The CT value, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and radiation dose in both groups were statistically analyzed.Results The consistency of uniform in artery image quality score and venous interference score was rather high according to the assessment of two physicians (Kappa=0.782 and 0.867). There was no statistical difference in artery image quality score, venous interference score, SNR and CNR between the two groups (Z=-0.864--0.032,P>0.05). The CT value in low dose group was higher than that in control group (differences with statistical significance,t=-8.789-1.715,P<0.05). The CT dose index of volume, dose-length product and effective dose in low dose group were all signiifcantly lower than those in control group (Z=-8.888,t=78.092 and 78.350, respectively,P<0.05).Conclusion The use of low tube voltage and low contrast dose in cerebral and carotid CTA examination can result in high quality images which meets the diagnostic needs and obviously reduce radiation dosage.

Objective To explore the safety and clinical effect of the human acellular nerve allograft (hANG) for repairing peripheral nerve defects.Methods During November,2009 to October,2010,6 patients with 3 digital nerve defects and 3 radial nerve defects were repaired with hANG.During postoperation period,safety was evaluated by local wound response and laboratory testing,while the efficacy was evaluated by British Medical Research Council sensory function assessment standards,static 2-point discrimination (2PD) and Semmes-Weinstein monofilament testing.Results Three patients with 6 digital nerve defects received hANG transplant.The length of nerve graft was 20-50 mm(mean 30.8 mm).After followed up for 31-40 months,the excellent rate of 2PD was 66.7％.Two of 3 patients rahabilited as well as the normal.Three patients with radial nerve defects,whose length of nerve graft was 35-60 mm(mean 48.3 mm).The strength of extensor carpiradialis longus muscle had restored Ⅲ in 1 case,and other 2 cases had no restoration.Conclusion hANG is safe and effective for repairing peripheral nerve defects,especially for digital nerve defects.