BACKGROUND:The imbalance between bone resorption and bone formation in microgravity environments leads to significant bone loss in astronauts.Current research indicates that bone loss under microgravity conditions is the result of the combined effects of various cells,tissues,and systems. OBJECTIVE:To review different biological effects of microgravity on various cells,tissues,or systems,and summarize the mechanisms by which microgravity leads to the development of osteoporosis. METHODS:Databases such as PubMed,Web of Science,and the Cochrane Database were searched for relevant literature from 2000 to 2023.The inclusion criteria were all articles related to tissue engineering studies and basic research on osteoporosis caused by microgravity.Ultimately,85 articles were included for review. RESULTS AND CONCLUSION:(1)In microgravity environment,bone marrow mesenchymal stem cells tend to differentiate more into adipocytes rather than osteoblasts,and hematopoietic stem cells in this environment are more inclined to differentiate into osteoclasts,reducing differentiation into the erythroid lineage.At the same time,microgravity inhibits the proliferation and differentiation of osteoblasts,promotes apoptosis of osteoblasts,alters cell morphology,and reduces the mineralization capacity of osteoblasts.Microgravity significantly increases the number and activity of osteoclasts.Microgravity also hinders the differentiation of osteoblasts into osteocytes and promotes the apoptosis of osteocytes.(2)In a microgravity environment,the body experiences changes such as skeletal muscle atrophy,microvascular remodeling,bone microcirculation disorders,and endocrine disruption.These changes lead to mechanical unloading in the bone microenvironment,insufficient blood perfusion,and calcium cycle disorders,which significantly impact the development of osteoporosis.(3)At present,the mechanism by which microgravity causes osteoporosis is relatively complex.A deeper study of these physiological mechanisms is crucial to ensuring the health of astronauts during long-term space missions,and provides a theoretical basis for the prevention and treatment of osteoporosis.

Objective:To develop and assess a three-class machine learning model for predicting wild-type, 19 del, and 21 L858R mutations of the epidermal growth factor receptor (EGFR) in lung adenocarcinoma using 18F-FDG PET/CT radiomic features and clinical features. Methods:The retrospective data was collected from 703 patients (346 males, 357 females; age (64.3±9.0) years) with lung adenocarcinoma at the First People′s Hospital of Changzhou from January 2018 to June 2023. Patients were divided into the training set (563 cases) and test set (140 cases) at the ratio of 8∶2. Clinical features were selected using recursive feature elimination (RFE). Radiomic features were extracted from PET and CT images, and the optimal feature sets were selected using minimum redundancy maximum relevance (mRMR) and least absolute shrinkage and selection operator (LASSO) methods. Base models were constructed by using random forest (RF), logistic regression (LR), support vector machine (SVM), K-nearest neighbors (KNN), and multi-layer perceptron (MLP), and the stacking method was applied to establish the CT and PET ensemble models. Delong test was used to compare the AUC differences between the PET/CT combined model and the clinical + PET/CT integrated model.Results:Among 703 patients, 273 were with EGFR wild-type, 202 were with 19 del mutation, and 228 were with 21 L858R mutation. In the single-modal analysis, the AUCs of CT ensemble model in the training and test sets were 0.893 and 0.667, respectively, while the AUCs of PET ensemble model were 0.692 and 0.660. The AUC of PET/CT combined model were 0.897 in training set and 0.672 in test set. The AUC of clinical + PET/CT integrated model showed further improvement, with AUCs of 0.902 and 0.721 in training and test sets, respectively. Notably, the clinical + PET/CT integrated model outperformed PET/CT combined model in predicting wild-type EGFR (test set AUC: 0.784 vs 0.707; Z=3.28, P=0.001). Conclusion:The three-class model (clinical + PET/CT integrated model) based on 18F-FDG PET/CT radiomics and clinical features effectively predicts EGFR mutation subtypes in lung adenocarcinoma.

Objective To investigate the correlation between skeletal muscle fat content and diabetic peripheral neuropathy(DPN)in patients with type 2 diabetes mellitus(T2DM).Methods 290 patients with T2DM admitted to our hospital were enrolled in this study from January 2023 to February 2024 and divided into two groups according to whether they were complicated with DPN:simple T2DM group(T2DM,n=98)and T2DM with DPN group(DPN,n=192).The general data,biochemical indexes and fat distribution indexes measured based on quantitative CT were compared between the two groups.Spearman correlation was used to analyze the relationship between fat distribution indexes and DPN,logistic regression analysis of influencing factors of T2DM complicated with DPN.Results Age,DM duration,WHR,FIns,insulin resistance index(HOMA-IR)and FF were higher in DPN group than in T2DM group(P<0.05).Ca,subcutaneous abdominal fat area(SFA)and liver fat content were lower in DPN group than in T2DM group(P<0.05).Spearman correlation analysis showed that DPN was negatively correlated with SFA and liver fat content(r=-0.127,-0.123,P<0.05),and positively correlated with FF(r=0.117,P<0.05).Logistic regression analysis showed that without adjusting for confounding factors and adjusting for DM duration,WHR,HOMA-IR,Ca,SFA and liver fat content,FF was an influential factor for DPN in T2DM patients.Conclusions Skeletal muscle FF was associated with DPN in patients with T2DM.

BACKGROUND:Wolff's law points out that the lack of mechanical stress in the body will lead to the degradation of the microstructure of bone tissue,mass loss,and metabolic disorders,and eventually lead to osteoporosis,which suggests that mechanical stress plays an important role in the growth,reconstruction,and formation of bone tissue.At present,the relevant studies concerning mechanical stress on osteoblasts mainly focus on fluid shear force,but it is difficult to intervene in vivo.Meanwhile,some studies have found that compressive stress can also play a similar role in fluid shear force to a certain extent.Exploring the mode of action and influence of compressive stress on cells in vitro experiments can enrich the interaction relationship between mechanical stress and cells.It helps provide a theoretical basis for studies of metabolic bone diseases,including osteoporosis,and other diseases.OBJECTIVE:To review in vitro experiments,the application of compressive stress to cells,different biological behaviors caused by cells,the possible signaling pathways,and possible future applications.METHODS:We searched PubMed,Web of Science,CNKI,and WanFang databases from January 2000 to March 2024 to include all articles related to compressive stress on cells,including basic research and microscopic mechanism studies,using search terms"compressive stress,mechanical stress,hydrostatic pressure,cell"in Chinese and English.Finally,the 63 included articles were reviewed.RESULTS AND CONCLUSION:(1)There are various ways to apply compressive stress,and different experimental equipment has different ways of pressurizing cells,so it is necessary to further standardize the experimental equipment,standardize the pressurization unit,reduce the confounding factors,and make the reference and comparability between different experimental groups.(2)Compressive stress can cause changes in cell proliferation,differentiation,autophagy,apoptosis,migration,etc.,and the effect of compressive stress is time-or dose-dependent in most cases.(3)At present,most in vitro experimental studies have shown that compressive stress may mainly act on osteoblasts through MAPK signaling pathway and Wnt/β-catenin signaling pathway,causing osteoblasts to produce different responses.(4)The effect of compressive stress on different cells is not the same,and its possible biological effects need to be studied.(5)Further research on compressive stress is helpful to provide a theoretical basis for treatment in orthopedics,stomatology,tumors and other fields,and gentle disinfection using hydrostatic pressure is a promising disinfection method.

ObjectiveTo observe the clinical effectiveness and safety of Xiaozhong Zhitong Mixture （消肿止痛合剂） combined with antibiotic bone cement in the treatment of diabetic foot ulcer （DFU） with damp-heat obstructing syndrome. MethodsA total of 72 DFU patients with damp-heat obstructing syndrome were randomly assigned to treatment group （36 cases） and the control group （36 cases）. Both groups received standard treatment and topical antibiotic bone cement for ulcer wounds， while the treatment group received oral Xiaozhong Zhitong Mixture （50 ml per time， three times daily） in additionally. Both groups underwent daily wound dressing changes for 21 consecutive days. Ulcer healing rate， serum levels of tumor necrosis factor-alpha （TNF-α）， interleukin-1 beta （IL-1β）， malondialdehyde （MDA）， superoxide dismutase （SOD）， C-reactive protein （CRP）， and white blood cell （WBC） count were observed before and after treatment， and visual analog scale （VAS） scores for wound pain， traditional Chinese medicine （TCM） syndrome scores， and the DFU Healing Scale （DMIST scale） were also compared. Liver and kidney function were evaluated before and after treatment， and adverse events such as allergic reactions， worsening ulcer pain were recorded. ResultsTotally 35 patients in the treatment group and 33 in the control group were included in the final analysis. The ulcer healing rate in the treatment group was （87.93±9.34）%， significantly higher than （81.82±12.02）% in the control group （P = 0.035）. Compared to pre-treatment levels， both groups showed significant reductions in serum CRP， WBC， MDA， IL-1β， and TNF-α levels， with an increase in SOD level （P＜0.05）. TCM syndrome scores， VAS， and DMIST scores also significantly decreased in both groups （P＜0.05）， with greater improvements in the treatment group （P＜0.05）. No significant adverse reactions were observed in either group during treatment. ConclusionXiaozhong Zhitong Mixture combined with antibiotic bone cement has significant advantages in promoting DFU healing， reducing inflammatory response， and alleviating oxidative stress in DFU patients with damp-heat obstructing syndrome， with good safety for DFU patients with damp-heat obstructing syndrome.

Objective To investigate the correlation between skeletal muscle fat content and diabetic peripheral neuropathy(DPN)in patients with type 2 diabetes mellitus(T2DM).Methods 290 patients with T2DM admitted to our hospital were enrolled in this study from January 2023 to February 2024 and divided into two groups according to whether they were complicated with DPN:simple T2DM group(T2DM,n=98)and T2DM with DPN group(DPN,n=192).The general data,biochemical indexes and fat distribution indexes measured based on quantitative CT were compared between the two groups.Spearman correlation was used to analyze the relationship between fat distribution indexes and DPN,logistic regression analysis of influencing factors of T2DM complicated with DPN.Results Age,DM duration,WHR,FIns,insulin resistance index(HOMA-IR)and FF were higher in DPN group than in T2DM group(P<0.05).Ca,subcutaneous abdominal fat area(SFA)and liver fat content were lower in DPN group than in T2DM group(P<0.05).Spearman correlation analysis showed that DPN was negatively correlated with SFA and liver fat content(r=-0.127,-0.123,P<0.05),and positively correlated with FF(r=0.117,P<0.05).Logistic regression analysis showed that without adjusting for confounding factors and adjusting for DM duration,WHR,HOMA-IR,Ca,SFA and liver fat content,FF was an influential factor for DPN in T2DM patients.Conclusions Skeletal muscle FF was associated with DPN in patients with T2DM.

BACKGROUND:Wolff's law points out that the lack of mechanical stress in the body will lead to the degradation of the microstructure of bone tissue,mass loss,and metabolic disorders,and eventually lead to osteoporosis,which suggests that mechanical stress plays an important role in the growth,reconstruction,and formation of bone tissue.At present,the relevant studies concerning mechanical stress on osteoblasts mainly focus on fluid shear force,but it is difficult to intervene in vivo.Meanwhile,some studies have found that compressive stress can also play a similar role in fluid shear force to a certain extent.Exploring the mode of action and influence of compressive stress on cells in vitro experiments can enrich the interaction relationship between mechanical stress and cells.It helps provide a theoretical basis for studies of metabolic bone diseases,including osteoporosis,and other diseases.OBJECTIVE:To review in vitro experiments,the application of compressive stress to cells,different biological behaviors caused by cells,the possible signaling pathways,and possible future applications.METHODS:We searched PubMed,Web of Science,CNKI,and WanFang databases from January 2000 to March 2024 to include all articles related to compressive stress on cells,including basic research and microscopic mechanism studies,using search terms"compressive stress,mechanical stress,hydrostatic pressure,cell"in Chinese and English.Finally,the 63 included articles were reviewed.RESULTS AND CONCLUSION:(1)There are various ways to apply compressive stress,and different experimental equipment has different ways of pressurizing cells,so it is necessary to further standardize the experimental equipment,standardize the pressurization unit,reduce the confounding factors,and make the reference and comparability between different experimental groups.(2)Compressive stress can cause changes in cell proliferation,differentiation,autophagy,apoptosis,migration,etc.,and the effect of compressive stress is time-or dose-dependent in most cases.(3)At present,most in vitro experimental studies have shown that compressive stress may mainly act on osteoblasts through MAPK signaling pathway and Wnt/β-catenin signaling pathway,causing osteoblasts to produce different responses.(4)The effect of compressive stress on different cells is not the same,and its possible biological effects need to be studied.(5)Further research on compressive stress is helpful to provide a theoretical basis for treatment in orthopedics,stomatology,tumors and other fields,and gentle disinfection using hydrostatic pressure is a promising disinfection method.

Objective:To develop and assess a three-class machine learning model for predicting wild-type, 19 del, and 21 L858R mutations of the epidermal growth factor receptor (EGFR) in lung adenocarcinoma using 18F-FDG PET/CT radiomic features and clinical features. Methods:The retrospective data was collected from 703 patients (346 males, 357 females; age (64.3±9.0) years) with lung adenocarcinoma at the First People′s Hospital of Changzhou from January 2018 to June 2023. Patients were divided into the training set (563 cases) and test set (140 cases) at the ratio of 8∶2. Clinical features were selected using recursive feature elimination (RFE). Radiomic features were extracted from PET and CT images, and the optimal feature sets were selected using minimum redundancy maximum relevance (mRMR) and least absolute shrinkage and selection operator (LASSO) methods. Base models were constructed by using random forest (RF), logistic regression (LR), support vector machine (SVM), K-nearest neighbors (KNN), and multi-layer perceptron (MLP), and the stacking method was applied to establish the CT and PET ensemble models. Delong test was used to compare the AUC differences between the PET/CT combined model and the clinical + PET/CT integrated model.Results:Among 703 patients, 273 were with EGFR wild-type, 202 were with 19 del mutation, and 228 were with 21 L858R mutation. In the single-modal analysis, the AUCs of CT ensemble model in the training and test sets were 0.893 and 0.667, respectively, while the AUCs of PET ensemble model were 0.692 and 0.660. The AUC of PET/CT combined model were 0.897 in training set and 0.672 in test set. The AUC of clinical + PET/CT integrated model showed further improvement, with AUCs of 0.902 and 0.721 in training and test sets, respectively. Notably, the clinical + PET/CT integrated model outperformed PET/CT combined model in predicting wild-type EGFR (test set AUC: 0.784 vs 0.707; Z=3.28, P=0.001). Conclusion:The three-class model (clinical + PET/CT integrated model) based on 18F-FDG PET/CT radiomics and clinical features effectively predicts EGFR mutation subtypes in lung adenocarcinoma.

Objective:To investigate the value of intratumoral and peritumoral radiomics models based on 18F-FDG PET-CT in predicting epidermal growth factor receptor (EGFR) mutation status in lung adenocarcinoma and interpret peritumoral radiomics features. Methods:This study was a cross-sectional study. Patients with lung adenocarcinoma who underwent 18F-FDG PET-CT at the Third Affiliated Hospital of Soochow University between January 2018 and April 2022 were retrospectively collected and samplied into a training set (309 cases) and a test set (206 cases) in a 6∶4 ratio randomly. Radiomics features were extracted from the intratumoral and peritumoral regions of interest based on PET and CT images, respectively, and the optimal feature sets were selected. Radiomics models were established using the XGBoost algorithm, and radiomics scores (intratumoral CT label, peritumoral CT label, intratumoral PET label, peritumoral PET label) were calculated. Logistic regression analysis was used to construct a clinical model and a combined model (incorporating PET-CT intratumoral and peritumoral radiomics, clinical features, and CT semantic features). The predictive performance of the models was evaluated using receiver operating characteristic curves and the area under the curve (AUC). Unsupervised clustering, Spearman correlation analysis, and visualization methods were used for the interpretability of peritumoral radiomics features. Results:In both the training and test sets, the AUC value of CT peritumoral labels was greater than that of CT intratumoral labels for predicting EGFR mutation status in lung adenocarcinoma (training set: Z=3.84, P<0.001; test set: Z=1.99, P=0.046). In the test set, the AUC value of PET intratumoral labels (0.684) was slightly higher than that of PET peritumoral labels (0.672) for predicting EGFR mutation status, but the difference was not statistically significant ( P>0.05). The combined model had the highest AUC value for predicting EGFR mutation status of lung adenocarcinoma in both the training and test sets and was significantly better than the clinical model (training set: Z=6.52, P<0.001; test set: Z=2.31, P=0.021). Interpretability analysis revealed that CT peritumoral radiomics features were correlated with CT shape features, and there were significant differences in CT peritumoral features between different EGFR mutation statuses. Conclusions:The value of CT peritumoral labels is superior to that of CT intratumoral labels in predicting EGFR mutation status in lung adenocarcinoma. The predictive performance of the model can be improved by combining PET-CT intratumoral and peritumoral radiomics, clinical features, and CT semantic features.

Objective:To evaluate the effect of flipped classroom combined with problem-based learning (PBL) on the standardized training for perioperative beside echocardiography.Methods:A total of 64 second-year standardized training students from the Department of Anesthesiology at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, were selected between January 2021 and June 2022 and assigned to control group ( n=32) and test group ( n=32) using a random number table method. Control group employed the traditional teaching model, and test group utilized the flipped classroom combined with PBL. After a 3-month period of teaching standard views and hemodynamic evaluation of bedside echocardiography, the comprehensive theoretical and clinical practice scores (a score of≥80 was considered excellent or good) were compared between the two groups. Additionally, a questionnaire was distributed to assess students′ self-directed learning ability and initiative, interest in learning, efficiency in mastering professional knowledge, satisfaction with teaching, communication and collaboration skills, and clinical thinking ability. Results:Compared with control group, the students in test group showed significant improvements in both comprehensive theoretical ([87 ± 8] vs [80 ± 8]) and clinical practical ([86 ± 8] vs [78 ± 8]) echocardiography scores( P<0.05 or 0.01).The excellent or good rate for comprehensive theoretical scores (88% vs 47%) and clinical practice scores (84% vs 50%) was significantly higher in test group than in control group( P<0.05 or 0.01).A total of 64 questionnaires were distributed, and all of them were returned, yielding a response rate of 100%. The students in test group demonstrated enhanced self-directed learning ability and initiative (94% vs 69%), increased interest in learning (91% vs 66%), improved efficiency in mastering professional knowledge (97% vs 75%), greater satisfaction with teaching (94% vs 62%), enhanced communication and collaboration skills (84% vs 62%), and improved clinical thinking ability (88% vs 59%) compared to control group ( P<0.05). Conclusions:The combination of a flipped classroom and PBL produces better effect than traditional teaching methods when used for standardized training for perioperative bedside echocardiography.