Objective:To investigate the feasibility and optimal expansion width of replacing the left anterior descending coronary artery (LADCA) with the region of heart sparing (RHS) to reduce cardiac radiation dose during breast cancer radiotherapy.Methods:Retrospective analysis was conducted on data from 88 patients with left-sided breast cancer who underwent radiotherapy at 2 centers: Nanfang Hospital of Southern Medical University (50 cases for the training set, 15 cases for the internal test set) and Ganzhou Hospital of Nanfang Hospital (23 cases for the external test set) from March 2022 to January 2024. All patients had left-sided invasive ductal carcinoma with axillary lymph node metastasis, and had undergone modified radical mastectomy and chemotherapy. Based on simulation CT images, 2 radiation oncologists delineated the LADCA and 8 RHSs. The RHSs were delineated by expanding the LADCA contour by 0.5 cm increments, totaling 8 expansions. The RHS widths were defined as 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 cm. The nnU-Net model was trained for 3D automatic segmentation of the LADCA and RHSs. Model performance was evaluated using the Dice similarity coefficient (DSC), relative volume error (RVE), sensitivity, specificity, and 95% Hausdorff distance (HD95). Additionally, the minimum, maximum, and average relative dose variations (RDV) as well as V5% and V20% indicators were calculated for the LADCA and each RHS. Correlation analysis was performed using the least squares regression, with the slope and coefficient of determination ( R2) employed to evaluate the accuracy of the model fitting, the relationship between the LADCA and RHS, and the degree of their correlation, thereby assessing the substitutive effect of the RHS for the LADCA. Results:The DSC for the LADCA was 0.415, while the DSCs for RHS widths of 0.5 cm and 4.0 cm were 0.718 and 0.835, respectively. Overall, the automatic segmentation performance improved with increasing RHS width. The DSC, RVE, sensitivity, specificity, and HD95 for the external test set were largely consistent with those of the internal test set, demonstrating the model's good robustness across different datasets. All RDVmin values were negative, while RDVmax and RDVmean showed a positive correlation with RHS width. RDVmean increased from 39.01% to 75.89% as the RHS width increased. In the correlation analysis, the slopes for RHS widths of 1.5 cm and 2.0 cm were 0.95 and 1.05, respectively, with R2 values and coefficients of variation of 0.79 and 0.73, and 21.11% and 24.03%, respectively. Conclusions:The automatic segmentation model trained on nnU-Net can accurately segment RHSs. Based on geometric and dosimetric indicators, a 1.5 cm-wide RHS is the most suitable substitute for the LADCA, effectively limiting the radiation dose to the LADCA without compromising target dose coverage.

Objective:To propose a semi-supervised learning method for dynamic generation of organ geometric contours, leveraging bladder volume variations and its relative position to the uterus to accurately generate uterine contours in cervical cancer radiotherapy.Methods:A total of 120 sets of pelvic planning CT images (including both full and empty bladder scans) from 60 patients with cervical cancer treated at the Department of Radiation Oncology, Nanfang Hospital of Southern Medical University between January and December 2023 were retrospectively collected. A conditional generative adversarial network (CGAN) based on a squeeze-and-excitation channel attention mechanism was proposed to accurately generate uterine geometric contours under varying bladder filling states. By emphasizing the critical spatial relationships between the bladder and uterus, the model learned the relative anatomical positions of pelvic organs and their motion correlations. The generative performance was quantitatively evaluated using the average Dice similarity coefficient (DSC), intersection over union (IoU), and the 95 th percentile Hausdorff distance (HD95), and was compared with GAN model, CGAN model, and Pix2Pix model. Pairwise comparisons were perfomed by paired-sample t-test. Results:The proposed SE-CGAN model achieved the best performance on the test set, with DSC of 0.83±0.09, IoU of 0.71±0.05, HD95 of (6.74±1.23) mm, improving DSC by 7.5%, 4.9%, and 3.6% compared to the GAN, CGAN, and Pix2Pix models, respectively (all P<0.001), and reducing the mean HD95 by 32.9%-45.3%. Statistical analysis revealed significant differences between SE-CGAN model and the other 3 baseline models, whereas no significant difference was observed between CGAN model and Pix2Pix model. The visualization results further demonstrated that the GAN model produced uterine contours deviated greatly from the real shape, and the edge was fuzzy; CGAN and Pix2Pix model achieved better overlap but lacked of precision in boundary reconstruction. In contrast, the contours generated by SE-CGAN model closely matched the ground truth with clearly defined edges, indicating superior reconstruction accuracy. Conclusions:In this study, we propose a generative adversarial network method that establishes a dynamic modulation mechanism by which the bladder state influences the uterine geometric contour, enabling accurate generation of the uterine contours from the bladder contours of any given localization CT scan. This approach effectively addresses the uncertainty in radiotherapy target delineation caused by pelvic organ motion.

Objective:To investigate the feasibility and optimal expansion width of replacing the left anterior descending coronary artery (LADCA) with the region of heart sparing (RHS) to reduce cardiac radiation dose during breast cancer radiotherapy.Methods:Retrospective analysis was conducted on data from 88 patients with left-sided breast cancer who underwent radiotherapy at 2 centers: Nanfang Hospital of Southern Medical University (50 cases for the training set, 15 cases for the internal test set) and Ganzhou Hospital of Nanfang Hospital (23 cases for the external test set) from March 2022 to January 2024. All patients had left-sided invasive ductal carcinoma with axillary lymph node metastasis, and had undergone modified radical mastectomy and chemotherapy. Based on simulation CT images, 2 radiation oncologists delineated the LADCA and 8 RHSs. The RHSs were delineated by expanding the LADCA contour by 0.5 cm increments, totaling 8 expansions. The RHS widths were defined as 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 cm. The nnU-Net model was trained for 3D automatic segmentation of the LADCA and RHSs. Model performance was evaluated using the Dice similarity coefficient (DSC), relative volume error (RVE), sensitivity, specificity, and 95% Hausdorff distance (HD95). Additionally, the minimum, maximum, and average relative dose variations (RDV) as well as V5% and V20% indicators were calculated for the LADCA and each RHS. Correlation analysis was performed using the least squares regression, with the slope and coefficient of determination ( R2) employed to evaluate the accuracy of the model fitting, the relationship between the LADCA and RHS, and the degree of their correlation, thereby assessing the substitutive effect of the RHS for the LADCA. Results:The DSC for the LADCA was 0.415, while the DSCs for RHS widths of 0.5 cm and 4.0 cm were 0.718 and 0.835, respectively. Overall, the automatic segmentation performance improved with increasing RHS width. The DSC, RVE, sensitivity, specificity, and HD95 for the external test set were largely consistent with those of the internal test set, demonstrating the model's good robustness across different datasets. All RDVmin values were negative, while RDVmax and RDVmean showed a positive correlation with RHS width. RDVmean increased from 39.01% to 75.89% as the RHS width increased. In the correlation analysis, the slopes for RHS widths of 1.5 cm and 2.0 cm were 0.95 and 1.05, respectively, with R2 values and coefficients of variation of 0.79 and 0.73, and 21.11% and 24.03%, respectively. Conclusions:The automatic segmentation model trained on nnU-Net can accurately segment RHSs. Based on geometric and dosimetric indicators, a 1.5 cm-wide RHS is the most suitable substitute for the LADCA, effectively limiting the radiation dose to the LADCA without compromising target dose coverage.

Objective:To propose a semi-supervised learning method for dynamic generation of organ geometric contours, leveraging bladder volume variations and its relative position to the uterus to accurately generate uterine contours in cervical cancer radiotherapy.Methods:A total of 120 sets of pelvic planning CT images (including both full and empty bladder scans) from 60 patients with cervical cancer treated at the Department of Radiation Oncology, Nanfang Hospital of Southern Medical University between January and December 2023 were retrospectively collected. A conditional generative adversarial network (CGAN) based on a squeeze-and-excitation channel attention mechanism was proposed to accurately generate uterine geometric contours under varying bladder filling states. By emphasizing the critical spatial relationships between the bladder and uterus, the model learned the relative anatomical positions of pelvic organs and their motion correlations. The generative performance was quantitatively evaluated using the average Dice similarity coefficient (DSC), intersection over union (IoU), and the 95 th percentile Hausdorff distance (HD95), and was compared with GAN model, CGAN model, and Pix2Pix model. Pairwise comparisons were perfomed by paired-sample t-test. Results:The proposed SE-CGAN model achieved the best performance on the test set, with DSC of 0.83±0.09, IoU of 0.71±0.05, HD95 of (6.74±1.23) mm, improving DSC by 7.5%, 4.9%, and 3.6% compared to the GAN, CGAN, and Pix2Pix models, respectively (all P<0.001), and reducing the mean HD95 by 32.9%-45.3%. Statistical analysis revealed significant differences between SE-CGAN model and the other 3 baseline models, whereas no significant difference was observed between CGAN model and Pix2Pix model. The visualization results further demonstrated that the GAN model produced uterine contours deviated greatly from the real shape, and the edge was fuzzy; CGAN and Pix2Pix model achieved better overlap but lacked of precision in boundary reconstruction. In contrast, the contours generated by SE-CGAN model closely matched the ground truth with clearly defined edges, indicating superior reconstruction accuracy. Conclusions:In this study, we propose a generative adversarial network method that establishes a dynamic modulation mechanism by which the bladder state influences the uterine geometric contour, enabling accurate generation of the uterine contours from the bladder contours of any given localization CT scan. This approach effectively addresses the uncertainty in radiotherapy target delineation caused by pelvic organ motion.

Objective To investigate the effect of active muscle response on mechanical responses and injuries of human neck under high Gx loading.Methods A refined finite element model of the head and neck with active muscle response was established and validated based on the existing post-crash volunteer experiments.The effects of active muscle action on the kinematic and biomechanical responses of the neck were investigated under different G-value loads and at each tilting angle using this model.Results The stress distribution of vertebrae under high Gx load was dispersed from C4-7 to the whole vertebrae,and the active muscle action reduced the stress change,and the effect was significant under 8 G acceleration,which reduced the peak vertebral bone stress by 23.6％and 11.6％,and the peak intervertebral disc stress by 42.3％and 63.4％under 8 G and 10 G conditions,respectively.The maximum stress difference of 34.3 MPa was achieved by the active muscle action at 15° backward tilting.Conclusions The neck showed better stability by the active muscle action under the impact of high Gx loading.At different tilting angles,the active muscle action was more obvious in the backward tilting posture compared with the forward tilting and upright seated postures,and the backward tilting posture was safer to meet the impact when the same active muscle action was applied.The results can provide a reference for the subsequent studies related to the neck injury.

Objective To investigate the effect of active muscle response on mechanical responses and injuries of human neck under high Gx loading.Methods A refined finite element model of the head and neck with active muscle response was established and validated based on the existing post-crash volunteer experiments.The effects of active muscle action on the kinematic and biomechanical responses of the neck were investigated under different G-value loads and at each tilting angle using this model.Results The stress distribution of vertebrae under high Gx load was dispersed from C4-7 to the whole vertebrae,and the active muscle action reduced the stress change,and the effect was significant under 8 G acceleration,which reduced the peak vertebral bone stress by 23.6％and 11.6％,and the peak intervertebral disc stress by 42.3％and 63.4％under 8 G and 10 G conditions,respectively.The maximum stress difference of 34.3 MPa was achieved by the active muscle action at 15° backward tilting.Conclusions The neck showed better stability by the active muscle action under the impact of high Gx loading.At different tilting angles,the active muscle action was more obvious in the backward tilting posture compared with the forward tilting and upright seated postures,and the backward tilting posture was safer to meet the impact when the same active muscle action was applied.The results can provide a reference for the subsequent studies related to the neck injury.

Objective To establish a coronavirus(CoV)infection model using human nasal mucosa organoids for testing antiviral drugs and evaluate the feasibility of using human nasal mucosa organoids with viral infection as platforms for viral research and antiviral drug development.Methods Human nasal mucosa organoids were tested for susceptibility to SARS-CoV-2 and HCoV-OC43 pseudoviruses.In a P3 laboratory,nasal mucosa organoids were infected with the original strain of SARS-CoV-2 and 4 variant strains,and the infection conditions were optimized.The viral loads in the culture supernatants were measured at different time points using RT-qPCR,and immunofluorescence assay was employed to localize SARS-CoV-2 nucleocapsid protein to determine the type of the infected cells.In the optimized nasal mucosa viral infection model,the antiviral effects of camostat and bergamot extract(which were known to inhibit SARS-CoV-2)were tested and the underlying molecular mechanisms were explored.Results In the optimized nasal mucosa organoid models infected with SARS-CoV-2 and HCoV-OC43 pseudoviruses,the viral load in the culture supernatants increased significantly during the period of 2 to 24 h following the infection,which confirmed infection of the organoids by both of the pseudoviruses.The nasal mucosa organoids could be stably infected by the original SARS-CoV-2 strain and its 4 variant strains,validating successful establishment of the viral infection model,in which both camostat and bergamot extract exhibited dose-dependent antiviral effects.Conclusions Human nasal mucosa organoids with SARS-CoV-2 infection can serve as platforms for screening and testing antiviral drugs,particularly those intended for nasal administration.

ObjectiveTo observe and compare the electrocardiogram index， myocardial morphology， and connexin 43 （Cx43） expression of two rat models of acute cerebral infarction （ACI） due to stasis combined with toxin complicated with cerebral-cardiac syndrome （CCS）， and to provide experimental evidence for the research on the occurrence mechanism of cardiac diseases induced by ACI and the clinical diagnosis and treatment of CCS. MethodSixty SPF-grade male SD rats were randomized into six groups （n=10）： normal ， syndrome of stasis combined with toxin induced by carrageenin combined with dry yeast （CA/Y）， multi-infarct induced by micro-embolism （ME）， middle cerebral artery occlusion （MCAO）， CA/Y+ME， and CA/Y+MCAO groups. The model of syndrome of stasis combined with toxin was established by intraperitoneal injection with carrageenan （CA） at 10 mg·kg^-1 on the first day and subcutaneous injection with dry yeast （Y） suspension （2 mg·kg^-1） on the second day of modeling. Twenty-four hours after the modeling of ACI， the electrocardiograms （ECGs） of rats in each group were collected and the number/percentage （%） of abnormal ECG was calculated. The infarct area of the brain was evaluated by 2，3，5-triphenyltetrazolium chloride （TTC） staining， and myocardial injury was assessed by hematoxylin-eosin （HE） staining. Immumohistochemical staining and Western blot were employed to determine the expression of Cx43 in the myocardium. ResultA certain number of rats in each model group presented abnormal ECG. Compared with the normal group and CA/Y group， CA/Y+MCAO group had the highest rate of abnormal ECG （P<0.01）. Compared with the normal， CA/Y， ME， and CA/Y+ME groups， the CA/Y+ME and CA/Y+MCAO groups showed decreased amplitudes of P-wave and T-wave， shortened P-R interval， and extended Q-T interval， which were particularly obvious in the CA/Y+MCAO group （P<0.05， P<0.01） and in accordance with the cerebral infarction area and pathological changes. The expression of Cx43 was up-regulated in both CA/Y+ME and CA/Y+MCAO groups， especially in the CA/Y+MCAO group （P<0.01）. ConclusionThe two rat models of ACI due to stasis combined with toxin complicated with CCS can be used to study the mechanism of heart diseases caused by cerebrovascular diseases and the therapeutic effects of Chinese medicines with the functions of resolving stasis and detoxifying. Moreover， the CA/Y+MCAO method has higher abnormal electrocardiogram rate， severer myocardial pathological injury， and higher expression of Cx43 protein. The models can be chosen according to specific experimental purpose.

Objective To investigate the correlation between brain injury and spleen damage in a rat model of acute ischemic stroke and stasis interaction,and its effect on the MCP-1/CCR2 axis,and to provide an experimental basis for the mechanism of brain-spleen inflammatory coupling in spleen lesions caused by acute ischemic stroke.Methods Forty male SD rats were randomly divided into a sham group,carrageenan/yeast stasis syndrome group(carrageenan/yeast,CA/Y),middle cerebral artery occlusion group(MCAO),and middle cerebral artery stasis syndrome group(MCAO CA/Y)with 10 rats in each group.CA/Y and MCAO CA/Y groups were injected with 10 mg/kg carrageenan and 10 mg/kg intraperitoneally on the first day of modeling.2 mg/kg of dry yeast suspension were injected subcutaneously on the second day.MCAO and MCAO CA/Y groups were established by wire embolism on the second day.At 24 h after cerebral infarction modeling,the neurological deficit score was calculated in each group,the percentage of the cerebral infarction area was determined by TTC staining,the spleen weight was measured,and the correlation between the percentage of the cerebral infarction area and spleen weight was analyzed by the Spearman correlation coefficient.Furthermore,the pathological morphology of brain and spleen tissues was observed by hematoxylin-eosin(HE)staining,and chemotactic protein 1(MCP-1)and interferon-γ(IFN-γ)contents were measured in rat plasma by enzyme-linked immunosorbent assays.Western blot was used to detect chemokine C-C-motif receptor 2(CCR2)protein expression in the ischemic side of brain tissue.Results Compared with the sham group,the neurological deficit score,cerebral infarction area,and MCP-1 and IFN-γ contents in plasma were significantly increased(P＜0.01),spleen weight was decreased significantly(P＜0.01),and CCR2 protein expression in brain tissue was significantly upregulated(P＜0.05)in MCAO and MCAO CA/Y groups.Moreover,the area of cerebral infarction was increased significantly(P＜0.01),the spleen weight was decreased significantly(P＜0.01),and CCR2 protein expression in brain and spleen tissues was significantly upregulated(P＜0.05)Compared with the MCAO group,the area of cerebral infarction in the MCAO CA/Y group was significantly increased(P＜0.01)and the spleen weight was decreased significantly(P＜0.05).Spearman correlation analysis showed that the spleen weight was negatively correlated to the percentage of the cerebral infarction area(P＜0.01,r=-0.9711).Pathological morphology observation revealed that the pathological changes in the MCAO CA/Y group were the most serious,cerebral liquefaction necrosis foci were seen in the brain tissue cortex,arrangement of neuronal cells in the lesions was sparse and disordered with volume atrophy and a small number of vacuoles and nuclear solidification,most neuronal cells were degenerated and necrotic,microglia hyperplasia was obvious,small blood vessels were significantly increased,and interstitial lipid degeneration was severe.The density of periarterial lymph sheath cells in some of the spleen tissue was reduced and the marginal area is widened.Conclusions A correlation between brain and spleen injury was found after acute ischemic stroke with stasis and toxin syndrome,and the chemokine signaling axis of MCP-1/CCR2 might be involved in the mechanism of brain-spleen inflammation coupling.

Objective To establish a coronavirus(CoV)infection model using human nasal mucosa organoids for testing antiviral drugs and evaluate the feasibility of using human nasal mucosa organoids with viral infection as platforms for viral research and antiviral drug development.Methods Human nasal mucosa organoids were tested for susceptibility to SARS-CoV-2 and HCoV-OC43 pseudoviruses.In a P3 laboratory,nasal mucosa organoids were infected with the original strain of SARS-CoV-2 and 4 variant strains,and the infection conditions were optimized.The viral loads in the culture supernatants were measured at different time points using RT-qPCR,and immunofluorescence assay was employed to localize SARS-CoV-2 nucleocapsid protein to determine the type of the infected cells.In the optimized nasal mucosa viral infection model,the antiviral effects of camostat and bergamot extract(which were known to inhibit SARS-CoV-2)were tested and the underlying molecular mechanisms were explored.Results In the optimized nasal mucosa organoid models infected with SARS-CoV-2 and HCoV-OC43 pseudoviruses,the viral load in the culture supernatants increased significantly during the period of 2 to 24 h following the infection,which confirmed infection of the organoids by both of the pseudoviruses.The nasal mucosa organoids could be stably infected by the original SARS-CoV-2 strain and its 4 variant strains,validating successful establishment of the viral infection model,in which both camostat and bergamot extract exhibited dose-dependent antiviral effects.Conclusions Human nasal mucosa organoids with SARS-CoV-2 infection can serve as platforms for screening and testing antiviral drugs,particularly those intended for nasal administration.