Objective To establish and validate a human comfort evaluation method based on musculoskeletal activity in biomechanics.Methods Firstly,the limitations of current biomechanical-based comfort evaluation method were analyzed.Secondly,a new evaluation method based on musculoskeletal activity was proposed,which considered the influence of muscle and joint on comfort,and a comfort index was obtained.Finally,the firefighter's water belt rolling task was selected for verification.Results The comfort index derived from the improved musculoskeletal activity-based evaluation method was 0.74,which was lower than the comfort index of 0.82 obtained from the comfort based on muscle activity.The verification results aligned with the theoretical analysis.A questionnaire survey conducted on 43 firefighters showed that the subjective assessments gathered were consistent with the verification outcomes,further confirming the conclusion that the former method was more comprehensive and accurate.Conclusions Compared to the method that focuses exclusively on muscle activity,the comfort evaluation method that integrates both muscle and joint conditions not only more accurately reflects the actual state of the human body but also comprehensively identifies potential biomechanical risks,thereby demonstrating greater practical significance.

Objective:To evaluate preoperative high-resolution thin-layer cervical enhanced CT used to predict the venous route of the submental flap reflux vein and its relationship with adjacent structures in order to guide the anatomical understanding and protection of submental flap in pharyngeal cancer surgery.Methods:Sixty consecutive patients with pharyngeal cancer who underwent submental flap repair surgery in our department from March 2022 to December 2024, as well as 60 patients who were accepted neck dissection suffering other cancers, were selected. Before surgery, high-resolution cervical enhanced CT scans were performed, and the position of the transverse section of the facial vein in the venous phase horizontal image gradually variation tendency was focused layer by layer. The direction and adjacent relationship of the submental flap reflux veins were determined and recorded. Combined with 60 patients with other head and neck tumors who underwent neck dissection in our department during the same period (a total of 120 cases, 240 sides), the classification and management of the draining veins of Fang′s mental flap were conducted. Type Ⅰ mainly drains into the internal jugular vein; Type Ⅱ mainly drains into the external jugular vein and Type Ⅲ mainly drains into the anterior jugular vein (often accompanied by an external jugular draining branch). The status and proportion of venous drainage were analyzed.Results:Vascular predictive coincidence rate was 98.3% (59/60) among the 60 patients with pharyngeal cancer. Only one patient was predicted to have a simple return to the external jugular vein. However, during the operation, in addition to the main return to the external jugular vein, a small portion also returned to the internal jugular vein. Submental flap reflux vessels were classified into three types based on intraoperative submental flap venous return in 60 cases of laryngopharyngeal cancer, in conjunction with the analysis of venous return patterns from 240 cervical CT scans. Type Ⅰ mainly refluxed to the internal jugular vein, accounting for 42.1%. Type Ⅱ mainly refluxed to the external jugular vein (47.9%). Type Ⅲ mainly refluxed to the anterior jugular vein (10.0%). The total detection rate of CT reading of 240 venous reflux was 98.7% (237/240). Vascular predictive coincidence rate was 97.9%(235/240).Conclusion:The detailed analysis of submental venous return vessels can accurately predict the direction of reflux veins and its surrounding areas by preoperative high-resolution enhanced CT scan. This provides reliable guidance for the anatomy and protection of the submental flap reflux veins during surgery.

Objective:To compare the survival outcomes of different subsequent treatment regimens in patients with locally advanced hypopharyngeal squamous cell carcinoma (HPSCC) who achieved partial response (PR) after neoadjuvant chemotherapy based on the gross tumor volume regression rate (GTVRR).Methods:This retrospective study included patients with locally advanced HPSCC treated at the Department of Head and Neck Surgery, Beijing Tongren Hospital, from January 2011 to December 2023. The cohort included 135 males and 3 females, aged from 35 to 77 years. All patients received 2-3 cycles of TPF regimen (paclitaxel+cisplatin+5-fluorouracil) neoadjuvant chemotherapy. Subsequent treatments included concurrent chemoradiotherapy or surgery combined with postoperative adjuvant radiotherapy. The impacts of different subsequent treatment modalities on the survivals and prognoses of patients were compared based on GTVRR thresholds of 50% and 70%. The χ 2 test was used to analyze influencing factors; survival analysis and intergroup comparisons were performed using the Kaplan-Meier method and Log-rank test; prognostic factors were assessed using univariate and multivariate Cox regression analyses. Results:The 5-year OS and PFS rates were 56.5% and 47.9%, respectively, while, the 10-year OS and PFS rates were 25.8% and 21.2%, respectively. The median OS was 75 months, and the median PFS was 48 months. The laryngeal function preservation rate for the entire cohort was 83.3%. The patients who underwent surgery combined with postoperative radiotherapy had significantly better OS and PFS outcomes than those treated with concurrent chemoradiotherapy ( P<0.05). Stratification based on GTVRR revealed that the surgery plus postoperative radiotherapy regimen was particularly effective for PR patients with a GTVRR of 30%-70%, showing significantly better OS and PFS compared to the concurrent chemoradiotherapy group ( P<0.05). Conclusion:The optimal subsequent treatment for PR-HPSCC may be surgery-based comprehensive treatment, particularly for patients with a GTVRR of 30%-70%. This study offers valuable insights for the stratified treatment of HPSCC, which could contribute to improving overall patient prognosis.

Objective:To evaluate preoperative high-resolution thin-layer cervical enhanced CT used to predict the venous route of the submental flap reflux vein and its relationship with adjacent structures in order to guide the anatomical understanding and protection of submental flap in pharyngeal cancer surgery.Methods:Sixty consecutive patients with pharyngeal cancer who underwent submental flap repair surgery in our department from March 2022 to December 2024, as well as 60 patients who were accepted neck dissection suffering other cancers, were selected. Before surgery, high-resolution cervical enhanced CT scans were performed, and the position of the transverse section of the facial vein in the venous phase horizontal image gradually variation tendency was focused layer by layer. The direction and adjacent relationship of the submental flap reflux veins were determined and recorded. Combined with 60 patients with other head and neck tumors who underwent neck dissection in our department during the same period (a total of 120 cases, 240 sides), the classification and management of the draining veins of Fang′s mental flap were conducted. Type Ⅰ mainly drains into the internal jugular vein; Type Ⅱ mainly drains into the external jugular vein and Type Ⅲ mainly drains into the anterior jugular vein (often accompanied by an external jugular draining branch). The status and proportion of venous drainage were analyzed.Results:Vascular predictive coincidence rate was 98.3% (59/60) among the 60 patients with pharyngeal cancer. Only one patient was predicted to have a simple return to the external jugular vein. However, during the operation, in addition to the main return to the external jugular vein, a small portion also returned to the internal jugular vein. Submental flap reflux vessels were classified into three types based on intraoperative submental flap venous return in 60 cases of laryngopharyngeal cancer, in conjunction with the analysis of venous return patterns from 240 cervical CT scans. Type Ⅰ mainly refluxed to the internal jugular vein, accounting for 42.1%. Type Ⅱ mainly refluxed to the external jugular vein (47.9%). Type Ⅲ mainly refluxed to the anterior jugular vein (10.0%). The total detection rate of CT reading of 240 venous reflux was 98.7% (237/240). Vascular predictive coincidence rate was 97.9%(235/240).Conclusion:The detailed analysis of submental venous return vessels can accurately predict the direction of reflux veins and its surrounding areas by preoperative high-resolution enhanced CT scan. This provides reliable guidance for the anatomy and protection of the submental flap reflux veins during surgery.

Objective:To compare the survival outcomes of different subsequent treatment regimens in patients with locally advanced hypopharyngeal squamous cell carcinoma (HPSCC) who achieved partial response (PR) after neoadjuvant chemotherapy based on the gross tumor volume regression rate (GTVRR).Methods:This retrospective study included patients with locally advanced HPSCC treated at the Department of Head and Neck Surgery, Beijing Tongren Hospital, from January 2011 to December 2023. The cohort included 135 males and 3 females, aged from 35 to 77 years. All patients received 2-3 cycles of TPF regimen (paclitaxel+cisplatin+5-fluorouracil) neoadjuvant chemotherapy. Subsequent treatments included concurrent chemoradiotherapy or surgery combined with postoperative adjuvant radiotherapy. The impacts of different subsequent treatment modalities on the survivals and prognoses of patients were compared based on GTVRR thresholds of 50% and 70%. The χ 2 test was used to analyze influencing factors; survival analysis and intergroup comparisons were performed using the Kaplan-Meier method and Log-rank test; prognostic factors were assessed using univariate and multivariate Cox regression analyses. Results:The 5-year OS and PFS rates were 56.5% and 47.9%, respectively, while, the 10-year OS and PFS rates were 25.8% and 21.2%, respectively. The median OS was 75 months, and the median PFS was 48 months. The laryngeal function preservation rate for the entire cohort was 83.3%. The patients who underwent surgery combined with postoperative radiotherapy had significantly better OS and PFS outcomes than those treated with concurrent chemoradiotherapy ( P<0.05). Stratification based on GTVRR revealed that the surgery plus postoperative radiotherapy regimen was particularly effective for PR patients with a GTVRR of 30%-70%, showing significantly better OS and PFS compared to the concurrent chemoradiotherapy group ( P<0.05). Conclusion:The optimal subsequent treatment for PR-HPSCC may be surgery-based comprehensive treatment, particularly for patients with a GTVRR of 30%-70%. This study offers valuable insights for the stratified treatment of HPSCC, which could contribute to improving overall patient prognosis.

Objective:To explore the role and related mechanism of myeloid related differentiation markers (MYADM) in lung adenocarcinoma metastasis induced by high cholesterol diet.Methods:(1) Cell experiments: Using lung adenocarcinoma A549 and H1975 cells, the cells were treated with 0.8 mg/ml cholesterol and then transfected with a lentivirus to knock down MYADM. The overexpression of MYADM was achieved by transfecting the cells with an overexpression plasmid. Western blotting was used to detect the expression levels of MYADM, E-cadherin, β-catenin, MMP-2, MMP-9, and vimentin in the cells. The proliferation ability of the cells was assessed using the plate clonal formation assay, while the migration and invasion ability were evaluated using the Transwell assay. Western blot was used to determine the effects of MYADM knockdown or overexpression on these proteins. Western blot and immunofluorescence assays were conducted to investigate the impact of Akt phosphorylation on the expression of MYADM and Rac1 in cholesterol-treated lung adenocarcinoma cells, as well as the phosphorylation of c-Myc. Western blot was also used to assess the effect of c-Myc knockdown on the expression of MYADM and MCT1 in lung adenocarcinoma cells. Chromatin immunoprecipitation (ChIP) assays were performed to investigate the impact of cholesterol on the binding between c-Myc and the promoters of MYADM and MCT1 in lung adenocarcinoma cells. (2) Animal experiment: A549 cells or A549 cells with MYADM knockdown were intravenously inoculated into BALB/c nude mice, which were then divided into a normal diet group and a high cholesterol diet group. Using a live imaging system, the growth and metastasis of tumors in the mice were monitored. After 42 days, lung tissues were collected for immunohistochemical staining to detect changes in relevant proteins.Results:After cholesterol treatment, the expression level of MYADM in A549 cells increased from 1.00±0.18 to 3.28±0.28 ( P<0.001), and in H1975 cells, it increased from 1.00±0.06 to 2.03±0.10 ( P<0.001). Compared with the control group, the expression of E-cadherin in lung adenocarcinoma cells after MYADM knockdown increased ( P<0.01), while the expressions of β-catenin, MMP-2, MMP-9, and vimentin decreased (all P<0.01). After MYADM knockdown, the number of clonal plates decreased in A549 cells (203±23 vs 60±18, t=8.48, P=0.001) and H1975 cells (298±64 vs 137±51, t=3.41, P=0.271). The number of invasive cells also decreased in A549 cells (212±18 vs 99±34, t=5.09, P=0.007) and H1975 cells (268±34 vs 134±14, t=6.31, P=0.003). Additionally, the number of migratory cells decreased in A549 cells (353±37 vs 124±29, t=8.44, P=0.001) and H1975 cells (279±41 vs 79±19, t=7.67, P=0.002). In the lung adenocarcinoma cells overexpressing MYADM, the expression of E-cadherin decreased ( P<0.01), while the levels of β-catenin, MMP-2, MMP-9, and vimentin increased (all P<0.01). The number of plate clonal colonies formed by lung adenocarcinoma cells overexpressing MYADM increased significantly in A549 cells, (94±26 vs 298±34, t=8.26, P=0.001) and H1975 cells (83±13 vs 331±24, t=15.74, P<0.001). The number of invasive A549 cells also increased (118±17 vs 193±24, t=4.41, P=0.012) and (156±19 vs 321±12, t=12.72, P<0.001). Additionally, the number of migrating cells increased in A549 cells (171±22 vs 284±15, t=7.35, P=0.002) and in H1975 cells (178±7 vs 263±12, t=10.6, P<0.001). Experiments related to the molecular mechanism showed that overexpression of MYADM promotes the expression of MCT1 in lung adenocarcinoma cells (all P<0.01). Cholesterol not only enhances the expression of MYADM in lung adenocarcinoma cells, but also boosts the expression of Rac1 and MCT1, as well as the phosphorylation of Akt and c-Myc (all P<0.05). Immunoprecipitation experiments revealed that in A549 cells treated with cholesterol, MYADM-Rac1 interaction levels increased from (100.0±15.9)% to (191.0±26.7)% ( P=0.007), while in H1975 cells, the levels increased from (100.0±18.2)% to (170.0±27.5)% ( P=0.021). ChIP confirmed that cholesterol treatment enhances the binding of c-Myc to the promoters of MYADM and MCT1. In vivo experiments demonstrated that a high-cholesterol diet promotes the metastasis of lung adenocarcinoma cells in mice, inducing the expression of MYADM, MCT1, and Rac1, as well as the phosphorylation of Akt and c-Myc in mouse lung tissue. Conversely, knocking down MYADM inhibits the metastasis of lung adenocarcinoma cells in mice, suppressing the expression of MYADM, MCT1, and Rac1, as well as the phosphorylation of Akt and c-Myc in mouse lung tissues. Conclusion:Cholesterol may induce lung adenocarcinoma cells proliferation and metastasis by regulating the MYADM/Rac1/Akt/c-Myc/MCT1 axis.

Objective:To explore the role and related mechanism of myeloid related differentiation markers (MYADM) in lung adenocarcinoma metastasis induced by high cholesterol diet.Methods:(1) Cell experiments: Using lung adenocarcinoma A549 and H1975 cells, the cells were treated with 0.8 mg/ml cholesterol and then transfected with a lentivirus to knock down MYADM. The overexpression of MYADM was achieved by transfecting the cells with an overexpression plasmid. Western blotting was used to detect the expression levels of MYADM, E-cadherin, β-catenin, MMP-2, MMP-9, and vimentin in the cells. The proliferation ability of the cells was assessed using the plate clonal formation assay, while the migration and invasion ability were evaluated using the Transwell assay. Western blot was used to determine the effects of MYADM knockdown or overexpression on these proteins. Western blot and immunofluorescence assays were conducted to investigate the impact of Akt phosphorylation on the expression of MYADM and Rac1 in cholesterol-treated lung adenocarcinoma cells, as well as the phosphorylation of c-Myc. Western blot was also used to assess the effect of c-Myc knockdown on the expression of MYADM and MCT1 in lung adenocarcinoma cells. Chromatin immunoprecipitation (ChIP) assays were performed to investigate the impact of cholesterol on the binding between c-Myc and the promoters of MYADM and MCT1 in lung adenocarcinoma cells. (2) Animal experiment: A549 cells or A549 cells with MYADM knockdown were intravenously inoculated into BALB/c nude mice, which were then divided into a normal diet group and a high cholesterol diet group. Using a live imaging system, the growth and metastasis of tumors in the mice were monitored. After 42 days, lung tissues were collected for immunohistochemical staining to detect changes in relevant proteins.Results:After cholesterol treatment, the expression level of MYADM in A549 cells increased from 1.00±0.18 to 3.28±0.28 ( P<0.001), and in H1975 cells, it increased from 1.00±0.06 to 2.03±0.10 ( P<0.001). Compared with the control group, the expression of E-cadherin in lung adenocarcinoma cells after MYADM knockdown increased ( P<0.01), while the expressions of β-catenin, MMP-2, MMP-9, and vimentin decreased (all P<0.01). After MYADM knockdown, the number of clonal plates decreased in A549 cells (203±23 vs 60±18, t=8.48, P=0.001) and H1975 cells (298±64 vs 137±51, t=3.41, P=0.271). The number of invasive cells also decreased in A549 cells (212±18 vs 99±34, t=5.09, P=0.007) and H1975 cells (268±34 vs 134±14, t=6.31, P=0.003). Additionally, the number of migratory cells decreased in A549 cells (353±37 vs 124±29, t=8.44, P=0.001) and H1975 cells (279±41 vs 79±19, t=7.67, P=0.002). In the lung adenocarcinoma cells overexpressing MYADM, the expression of E-cadherin decreased ( P<0.01), while the levels of β-catenin, MMP-2, MMP-9, and vimentin increased (all P<0.01). The number of plate clonal colonies formed by lung adenocarcinoma cells overexpressing MYADM increased significantly in A549 cells, (94±26 vs 298±34, t=8.26, P=0.001) and H1975 cells (83±13 vs 331±24, t=15.74, P<0.001). The number of invasive A549 cells also increased (118±17 vs 193±24, t=4.41, P=0.012) and (156±19 vs 321±12, t=12.72, P<0.001). Additionally, the number of migrating cells increased in A549 cells (171±22 vs 284±15, t=7.35, P=0.002) and in H1975 cells (178±7 vs 263±12, t=10.6, P<0.001). Experiments related to the molecular mechanism showed that overexpression of MYADM promotes the expression of MCT1 in lung adenocarcinoma cells (all P<0.01). Cholesterol not only enhances the expression of MYADM in lung adenocarcinoma cells, but also boosts the expression of Rac1 and MCT1, as well as the phosphorylation of Akt and c-Myc (all P<0.05). Immunoprecipitation experiments revealed that in A549 cells treated with cholesterol, MYADM-Rac1 interaction levels increased from (100.0±15.9)% to (191.0±26.7)% ( P=0.007), while in H1975 cells, the levels increased from (100.0±18.2)% to (170.0±27.5)% ( P=0.021). ChIP confirmed that cholesterol treatment enhances the binding of c-Myc to the promoters of MYADM and MCT1. In vivo experiments demonstrated that a high-cholesterol diet promotes the metastasis of lung adenocarcinoma cells in mice, inducing the expression of MYADM, MCT1, and Rac1, as well as the phosphorylation of Akt and c-Myc in mouse lung tissue. Conversely, knocking down MYADM inhibits the metastasis of lung adenocarcinoma cells in mice, suppressing the expression of MYADM, MCT1, and Rac1, as well as the phosphorylation of Akt and c-Myc in mouse lung tissues. Conclusion:Cholesterol may induce lung adenocarcinoma cells proliferation and metastasis by regulating the MYADM/Rac1/Akt/c-Myc/MCT1 axis.

Objective To establish and validate a human comfort evaluation method based on musculoskeletal activity in biomechanics.Methods Firstly,the limitations of current biomechanical-based comfort evaluation method were analyzed.Secondly,a new evaluation method based on musculoskeletal activity was proposed,which considered the influence of muscle and joint on comfort,and a comfort index was obtained.Finally,the firefighter's water belt rolling task was selected for verification.Results The comfort index derived from the improved musculoskeletal activity-based evaluation method was 0.74,which was lower than the comfort index of 0.82 obtained from the comfort based on muscle activity.The verification results aligned with the theoretical analysis.A questionnaire survey conducted on 43 firefighters showed that the subjective assessments gathered were consistent with the verification outcomes,further confirming the conclusion that the former method was more comprehensive and accurate.Conclusions Compared to the method that focuses exclusively on muscle activity,the comfort evaluation method that integrates both muscle and joint conditions not only more accurately reflects the actual state of the human body but also comprehensively identifies potential biomechanical risks,thereby demonstrating greater practical significance.

In December 2018, a 21-year old male with a whole-hand degloving injury was treated in the Department of Hand Surgery, Longgang District Orthopaedic Hospital. Two hallux nail flaps were used to reconstruct the right thumb, index finger and the first web. The wounds on middle, ring and little fingers were reconstructed with syndactyly by a left anterolateral thigh flap (ALTF). A right ALTF was used to reconstruct the donor sites in both feet. After 2 surgeries for finger splitting, the pulps of right middle, ring and little fingers were reconstructed with the pulps of the right middle, ring and little fingers together with the lateral flaps of the second toes of both feet and left third toe. After 4 years of follow-up, nails of the thumb and index finger were realistic and the shape of the fingers was satisfactory. There was no wear or ulceration in the finger pulps. The holding function was good with the TPD at 4-6 mm. There was no blisters or ulcers in both feet. The flap was soft. Only linear scars remained on both thighs.

In December 2018, a 21-year old male with a whole-hand degloving injury was treated in the Department of Hand Surgery, Longgang District Orthopaedic Hospital. Two hallux nail flaps were used to reconstruct the right thumb, index finger and the first web. The wounds on middle, ring and little fingers were reconstructed with syndactyly by a left anterolateral thigh flap (ALTF). A right ALTF was used to reconstruct the donor sites in both feet. After 2 surgeries for finger splitting, the pulps of right middle, ring and little fingers were reconstructed with the pulps of the right middle, ring and little fingers together with the lateral flaps of the second toes of both feet and left third toe. After 4 years of follow-up, nails of the thumb and index finger were realistic and the shape of the fingers was satisfactory. There was no wear or ulceration in the finger pulps. The holding function was good with the TPD at 4-6 mm. There was no blisters or ulcers in both feet. The flap was soft. Only linear scars remained on both thighs.