Objective To explore the feasibility and safety of non-anticoagulation veno-venous extracorporeal membrane oxygenation(VV-ECMO)in patients with severe chest trauma.Methods A retrospective cohort study method was used.A total of 19 patients with severe chest trauma who received VV-ECMO with a delayed anticoagulation strategy at Zhengzhou Central Hospital Affiliated to Zhengzhou University from January 2018 to October 2021 were included in the delayed anticoagulation group,and 20 patients with severe chest trauma who received VV-ECMO with a non-anticoagulation strategy from November 2021 to October 2024 were included in the non-anticoagulation group.The overall clinical characteristics of the patients were statistically analyzed,including gender,age,injury severity score(ISS),acute physiology and chronic health evaluationⅡ(APACHEⅡ),reason for VV-ECMO,use of vasoactive drugs,oxygenation index(PaO2/FiO2),and interval from injury to VV-ECMO.The primary outcomes were hemorrhagic and thrombotic complications.The secondary outcomes were blood transfusion during VV-ECMO,VV-ECMO time,mechanical ventilation time,intensive care unit(ICU)length of stay,and 28-day mortality.Results There was no significant difference in gender,age,ISS score,APACHEⅡscore,reason for VV-ECMO,use of vasoactive drugs,PaO2/FiO2,and interval from injury to VV-ECMO between the non-anticoagulation group and the delayed anticoagulation group.There was no significant difference in overall incidence of hemorrhagic and thrombotic between the two groups[incidence of hemorrhagic complications:15.0%(3/20)vs.31.6%(6/19),incidence of thrombotic:15.0%(3/20)vs.5.3%(1/19),both P>0.05].The infusion rate of 4 or more paked red blood cell(PRBC)within 24 hours during VV-ECMO in the non-anticoagulation group was significantly lower than that in the delayed anticoagulation group[5.0%(1/20)vs.31.6%(6/19),P<0.05].The amount of PRBC and platelet transfusion and the time on VV-ECMO in the non-anticoagulation group during VV-ECMO were significantly lower than those in the delayed anticoagulation group[PRBC(U):5.8±3.8 vs.8.1±3.1,platelets(U):1(0,1)vs.2(1,3),time on VV-ECMO(hours):71.55±24.37 vs.114.21±34.08,all P<0.05].There were no statistically significant differences in the amount of plasma and cryoprecipitate transfusion during VV-ECMO,mechanical ventilation time,ICU hospitalization time,and 28-day mortality between the two groups.Conclusion For patients with severe chest trauma receiving VV-ECMO withholding routine systemic anticoagulation did not result in thrombotic complications or higher mortality and required less PRBC and platelet transfusions.Non-anticoagulant VV-ECMO is safe and feasible for patients with severe chest trauma with high risk of bleeding.

Encephalomyocarditis virus(EMCV)is a zoonotic pathogen that causes encephalitis and myocarditis as its primary clinical manifestations.To explore effective preventive measures,this study utilized a Bac-to-Bac expression system to insert the EMCV P12A and 3C genes into the pFastBacDual shuttle vector,resulting in the generation of the recombinant baculovirus Ac-P12A-3C.This facilitated the large-scale expression and purification of EMCV virus-like particles(VLPs),which were correctly assembled into particles of approximately 30 nm in diameter,as ob-served by electron microscopy.Immunization and challenge experiments in mice demonstrated that these VLPs could effectively protect against EMCV infection,achieving a protection rate of 100％.Histopathological sections indicated that,compared to the PBS control group,the VLP immuniza-tion group exhibited significantly reduced tissue damage,along with a marked decrease in viral load within the tissues.In piglets,immunization with the VLPs elicited a robust humoral response,with neutralizing antibody titers reaching 1∶320 to 1∶640 after a second immunization,and no signifi-cant adverse reactions were observed throughout the immunization process.This study preliminarily explores the immunogenicity and safety of the VLP vaccine,laying the foundation for the development of a subunit vaccine based on EMCV VLPs and offering a new strategy for the prevention and control of encephalomyocarditis.

AIM To investigate the tumor-suppressive mechanism of Guiqi Yiyuan Extract combined with cisplatin in Lewis lung cancer mice.METHODS Ten intact C57BL/6J mice were assigned to the blank group.Sixty additional mice were developed into Lewis lung cancer models bearing transplanted tumor and subsequently allocated into the model group,the cisplatin group(5 mg/kg),the high-dose Guiqi Yiyuan Extract group(6.6 g/kg),and the low-dose,medium-dose and high-dose Guiqi Yiyuan Extract combined with cisplatin group(1.6,3.3,6.6 g/kg+5 mg/kg),with 10 mice in each group.Mice in the blank and model groups received saline via daily gavage,while treatment groups were administered Guiqi Yiyuan Extract orally(once daily),and cisplatin injection intraperitoneally(once every other day).After 14 days of drug administration,mice were euthanized for endpoint analysis.The following assessments were conducted:general health status and body weight changes monitored throughout the study period;tumor excision and weighing for inhibition rate calculation;histopathological examination of tumors via hematoxylin-eosin(HE)staining;serum quantification of IL-1 β,IL-18 and HMGB1 by ELISA;ultrastructural analysis of tumor cell death using transmission electron microscopy(TEM);spatial localization of TXNIP and GSDMD-N in tumor sections via immunofluorescence(IF);and Western blot detection of TXNIP,NLRP3,Caspase-1,cleaved Caspase-1,GSDMD,GSDMD-N protein expressions in tumor tissues.RESULTS Compared to the model group,the cisplatin group and all combination therapy groups exhibited significant reduction in tumor weight(P＜0.05)and increased tumor suppression rate;enhanced tumor tissue necrosis with characteristic pyroptotic morphology;elevated serum levels of IL-1β,IL-18 and HMGB1(P＜0.05);and upregulated expressions of pyroptosis-associated proteins TXNIP,NLRP3,Caspase-1,cleaved Caspase-1,GSDMD and GSDMD-N(P＜0.05).The high dose combination group demonstrated optimal therapeutic efficacy(P＜0.05).CONCLUSION Guiqi Yiyuan Extract enhances cisplatin sensitivity,demonstrating synergistic anti-tumor effects in Lewis lung carcinoma-bearing mice.This combinatorial therapeutic effect likely involves modulation of the TXNIP/NLRP3/Caspase-1/GSDMD pathway.

Objective:Explore the protective effect and mechanism of methyl badosolone (CDDO-Me) on rats with traumatic brain injury (TBI).Methods:A total of 72 SPF-grade SD rats aged 8 weeks were randomly (random number) divided into 4 groups ( n=18) using the random number table method: Sham, TBI, TBI+Vehicle, and TBI+CDDO-Me. The rat TBI model was established using the hydraulic impact head injury method. The TBI+CDDO-Me group was administered CDDO-Me (dissolved in 1% DMSO, at a dose of 10 mg/kg) via intraperitoneal injection 30 minutes after modeling, twice a day for a total of 3 days. On the third day after modeling, brain tissue was collected for pathological and water content detection after mNSS scoring. Immunofluorescence double staining was used to detect the expression of nuclear factor erythroid2 related factor 2 (Nrf2); immunohistochemical staining was used to detect the expression of ionized calcium binding adapter molecule-1(Iba-1); ELISA was used to detect the levels of tumor necrosis factor-α(TNF-α), interleukin (IL)-1β, and IL-18 in serum; kits were used to detect the levels of malondialdehyde (MDA) and reactive oxygen species (ROS); Western blot was used to detect the expression of the Nrf2 pathway, B-cell lymphoma-2 (BCL-2), and BCL-2 associated X protein (BAX). Results:(1) Compared with the Sham group, the mNSS scores and water content in the injured cortex of the TBI group rats were significantly increased (both P<0.05), and both significantly decreased after CDDO-Me intervention (both P<0.05). (2) Compared with the Sham group, the proportion of Nissl-stained injured neurons and apoptotic positive cells in the TBI group rats were significantly increased (both P<0.05), and both significantly decreased after CDDO-Me intervention (both P<0.05), accompanied by a decrease in BAX protein expression and upregulation of BCL-2 protein expression (both P<0.05). (3) Immunofluorescence and Western blot results showed that compared with the Sham group, the expression of total Nrf2, nuclear Nrf2, HO-1, and NQO1 proteins in the TBI group were all increased (all P<0.05), and the increase was more significant after CDDO-Me intervention (all P<0.05). (4) Immunohistochemistry and ELISA results showed that compared with the Sham group, the levels of MDA, ROS, Iba-1 in brain tissue and the levels of TNF-α, IL-1β, and IL-18 in serum in the TBI group rats were all significantly increased (all P<0.05), and all significantly decreased after CDDO-Me intervention (all P<0.05). Conclusion:CDDO-Me helps to reduce oxidative stress and inflammatory responses in TBI rats, and the mechanism may be related to the activation of the Nrf2/HO-1 antioxidant stress pathway.

AIM To investigate the tumor-suppressive mechanism of Guiqi Yiyuan Extract combined with cisplatin in Lewis lung cancer mice.METHODS Ten intact C57BL/6J mice were assigned to the blank group.Sixty additional mice were developed into Lewis lung cancer models bearing transplanted tumor and subsequently allocated into the model group,the cisplatin group(5 mg/kg),the high-dose Guiqi Yiyuan Extract group(6.6 g/kg),and the low-dose,medium-dose and high-dose Guiqi Yiyuan Extract combined with cisplatin group(1.6,3.3,6.6 g/kg+5 mg/kg),with 10 mice in each group.Mice in the blank and model groups received saline via daily gavage,while treatment groups were administered Guiqi Yiyuan Extract orally(once daily),and cisplatin injection intraperitoneally(once every other day).After 14 days of drug administration,mice were euthanized for endpoint analysis.The following assessments were conducted:general health status and body weight changes monitored throughout the study period;tumor excision and weighing for inhibition rate calculation;histopathological examination of tumors via hematoxylin-eosin(HE)staining;serum quantification of IL-1 β,IL-18 and HMGB1 by ELISA;ultrastructural analysis of tumor cell death using transmission electron microscopy(TEM);spatial localization of TXNIP and GSDMD-N in tumor sections via immunofluorescence(IF);and Western blot detection of TXNIP,NLRP3,Caspase-1,cleaved Caspase-1,GSDMD,GSDMD-N protein expressions in tumor tissues.RESULTS Compared to the model group,the cisplatin group and all combination therapy groups exhibited significant reduction in tumor weight(P＜0.05)and increased tumor suppression rate;enhanced tumor tissue necrosis with characteristic pyroptotic morphology;elevated serum levels of IL-1β,IL-18 and HMGB1(P＜0.05);and upregulated expressions of pyroptosis-associated proteins TXNIP,NLRP3,Caspase-1,cleaved Caspase-1,GSDMD and GSDMD-N(P＜0.05).The high dose combination group demonstrated optimal therapeutic efficacy(P＜0.05).CONCLUSION Guiqi Yiyuan Extract enhances cisplatin sensitivity,demonstrating synergistic anti-tumor effects in Lewis lung carcinoma-bearing mice.This combinatorial therapeutic effect likely involves modulation of the TXNIP/NLRP3/Caspase-1/GSDMD pathway.

Objective To explore the feasibility and safety of non-anticoagulation veno-venous extracorporeal membrane oxygenation(VV-ECMO)in patients with severe chest trauma.Methods A retrospective cohort study method was used.A total of 19 patients with severe chest trauma who received VV-ECMO with a delayed anticoagulation strategy at Zhengzhou Central Hospital Affiliated to Zhengzhou University from January 2018 to October 2021 were included in the delayed anticoagulation group,and 20 patients with severe chest trauma who received VV-ECMO with a non-anticoagulation strategy from November 2021 to October 2024 were included in the non-anticoagulation group.The overall clinical characteristics of the patients were statistically analyzed,including gender,age,injury severity score(ISS),acute physiology and chronic health evaluationⅡ(APACHEⅡ),reason for VV-ECMO,use of vasoactive drugs,oxygenation index(PaO2/FiO2),and interval from injury to VV-ECMO.The primary outcomes were hemorrhagic and thrombotic complications.The secondary outcomes were blood transfusion during VV-ECMO,VV-ECMO time,mechanical ventilation time,intensive care unit(ICU)length of stay,and 28-day mortality.Results There was no significant difference in gender,age,ISS score,APACHEⅡscore,reason for VV-ECMO,use of vasoactive drugs,PaO2/FiO2,and interval from injury to VV-ECMO between the non-anticoagulation group and the delayed anticoagulation group.There was no significant difference in overall incidence of hemorrhagic and thrombotic between the two groups[incidence of hemorrhagic complications:15.0%(3/20)vs.31.6%(6/19),incidence of thrombotic:15.0%(3/20)vs.5.3%(1/19),both P>0.05].The infusion rate of 4 or more paked red blood cell(PRBC)within 24 hours during VV-ECMO in the non-anticoagulation group was significantly lower than that in the delayed anticoagulation group[5.0%(1/20)vs.31.6%(6/19),P<0.05].The amount of PRBC and platelet transfusion and the time on VV-ECMO in the non-anticoagulation group during VV-ECMO were significantly lower than those in the delayed anticoagulation group[PRBC(U):5.8±3.8 vs.8.1±3.1,platelets(U):1(0,1)vs.2(1,3),time on VV-ECMO(hours):71.55±24.37 vs.114.21±34.08,all P<0.05].There were no statistically significant differences in the amount of plasma and cryoprecipitate transfusion during VV-ECMO,mechanical ventilation time,ICU hospitalization time,and 28-day mortality between the two groups.Conclusion For patients with severe chest trauma receiving VV-ECMO withholding routine systemic anticoagulation did not result in thrombotic complications or higher mortality and required less PRBC and platelet transfusions.Non-anticoagulant VV-ECMO is safe and feasible for patients with severe chest trauma with high risk of bleeding.

Objective:To preliminarily explore whether sirtuin1 (SIRT1) activation can inhibit neuronal ferroptosis in rats after traumatic brain injury (TBI) by regulating hypoxia-inducible factor-1α (HIF-1α)-mediated glycolysis.Methods:(1) Six SD rats were randomly divided into sham-operated group and TBI group, with 3 rats in each group; TBI model in the TBI group was established by hydraulic impact method, and rats in the sham-operated group underwent same surgery without impact. Cortical tissues of the two groups were sent for tandem mass tag (TMT) labeled quantitative proteomics detection to analyze the differential expression proteome; Kyoto encyclopedia of genes and genomes (KEGG) and gene set enrichment analysis (GSEA) were used to detect pathway enrichment of the screened differential proteins. (2) Twelve SD rats were randomly divided into sham-operated group and 1-day, 3-day and 7-day post-TBI groups, with 3 rats in each group. Treatment methods were the same as above; Western blotting was used to detect SIRT1 protein expression. (3) Forty-eight rats were randomly divided into sham-operated group, TBI group, TBI+vehicle group and TBI+SIRT1 agonist group, with 12 rats in each group; rats in the sham-operated group and TBI group accepted treatment as above; rats in the TBI+SIRT1 agonist group were intraperitoneally injected with SRT1720 (dissolved in ≤ 5% dimethyl sulfoxide, at a dose of 20 mg/kg) within 30 minutes after modeling, twice a day (with an interval of 12 hours); and rats in the TBI+vehicle group were injected with same dose of dimethyl sulfoxide at the same time. One d after modeling, neurological deficit was assessed using modified Neurological severity score (mNSS), brain water content was measured by dry-wet weight method, histopathological changes in the cortical lesions were observed by HE staining, mitochondrial ultrastructure was examined by transmission electron microscopy, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in the brain tissues were detected by colorimetry, and protein expressions of SIRT1, HIF-1α (key protein in the glycolytic pathway), glutathione peroxidase 4 (GPX4, key protein in the ferroptosis pathway), and acyl-CoA synthetase long-chain family member 4 (ACSL4, key protein in the ferroptosis pathway) were evaluated by Western blotting.Results:(1) KEGG analysis revealed that the glycolysis pathway and HIF-1 signaling pathway were obviously enriched in the cortical tissues of rats in the TBI group compared with the sham-operated group; GSEA showed that the HIF-1 signaling pathway (mmu04066) and ferroptosis pathway (mmu04216) gene sets in the cortical tissues of rats in the TBI group exhibited enrichment trends compared with those in the sham-operated group. (2) Compared with the sham-operated group, the 1-day, 3-day, and 7-day post-TBI groups had significantly decreased SIRT1 protein expression ( P<0.05), with the most prominent decline in 1-day post-TBI group. (3) Compared with the TBI+vehicle group, rats in the TBI+SIRT1 agonist group showed significantly reduced mNSS score and brain tissue water content (9.83±1.17 vs. 7.66±1.21; [83.62±0.91]% vs. [80.09±0.68]%, P<0.05). HE staining indicated clearer structure of the cortical area at the injury sites, and improved neuron morphology in the TBI+SIRT1 agonist group compared with those in the TBI+vehicle group; and transmission electron microscopy showed reduced mitochondrial shrinkage and partial restoration of cristae structures in the TBI+SIRT1 agonist group compared with those in the TBI+vehicle group. Compared with the TBI+vehicle group, the TBI+SIRT1 agonist group exhibited significantly decreased MDA content ([62.72±9.20] nmol/g vs. [39.34±3.48] nmol/g), increased SOD activity ([1.95±0.23] U/mg vs. [2.48±0.14] U/mg), elevated GPX4 protein expression (0.37±0.04 vs. 0.46±0.03), and decreased HIF-1α and ACSL4 protein expressions (1.16±0.15 vs. 0.81±0.12; 1.14±0.06 vs. 1.29±0.04), with significant differences ( P<0.05). Conclusion:SIRT1 activation can exert neuroprotective effect by inhibiting HIF-1α-mediated glycolysis and reducing neuronal ferroptosis after TBI.

Encephalomyocarditis virus(EMCV)is a zoonotic pathogen that causes encephalitis and myocarditis as its primary clinical manifestations.To explore effective preventive measures,this study utilized a Bac-to-Bac expression system to insert the EMCV P12A and 3C genes into the pFastBacDual shuttle vector,resulting in the generation of the recombinant baculovirus Ac-P12A-3C.This facilitated the large-scale expression and purification of EMCV virus-like particles(VLPs),which were correctly assembled into particles of approximately 30 nm in diameter,as ob-served by electron microscopy.Immunization and challenge experiments in mice demonstrated that these VLPs could effectively protect against EMCV infection,achieving a protection rate of 100％.Histopathological sections indicated that,compared to the PBS control group,the VLP immuniza-tion group exhibited significantly reduced tissue damage,along with a marked decrease in viral load within the tissues.In piglets,immunization with the VLPs elicited a robust humoral response,with neutralizing antibody titers reaching 1∶320 to 1∶640 after a second immunization,and no signifi-cant adverse reactions were observed throughout the immunization process.This study preliminarily explores the immunogenicity and safety of the VLP vaccine,laying the foundation for the development of a subunit vaccine based on EMCV VLPs and offering a new strategy for the prevention and control of encephalomyocarditis.

Objective:To preliminarily explore whether sirtuin1 (SIRT1) activation can inhibit neuronal ferroptosis in rats after traumatic brain injury (TBI) by regulating hypoxia-inducible factor-1α (HIF-1α)-mediated glycolysis.Methods:(1) Six SD rats were randomly divided into sham-operated group and TBI group, with 3 rats in each group; TBI model in the TBI group was established by hydraulic impact method, and rats in the sham-operated group underwent same surgery without impact. Cortical tissues of the two groups were sent for tandem mass tag (TMT) labeled quantitative proteomics detection to analyze the differential expression proteome; Kyoto encyclopedia of genes and genomes (KEGG) and gene set enrichment analysis (GSEA) were used to detect pathway enrichment of the screened differential proteins. (2) Twelve SD rats were randomly divided into sham-operated group and 1-day, 3-day and 7-day post-TBI groups, with 3 rats in each group. Treatment methods were the same as above; Western blotting was used to detect SIRT1 protein expression. (3) Forty-eight rats were randomly divided into sham-operated group, TBI group, TBI+vehicle group and TBI+SIRT1 agonist group, with 12 rats in each group; rats in the sham-operated group and TBI group accepted treatment as above; rats in the TBI+SIRT1 agonist group were intraperitoneally injected with SRT1720 (dissolved in ≤ 5% dimethyl sulfoxide, at a dose of 20 mg/kg) within 30 minutes after modeling, twice a day (with an interval of 12 hours); and rats in the TBI+vehicle group were injected with same dose of dimethyl sulfoxide at the same time. One d after modeling, neurological deficit was assessed using modified Neurological severity score (mNSS), brain water content was measured by dry-wet weight method, histopathological changes in the cortical lesions were observed by HE staining, mitochondrial ultrastructure was examined by transmission electron microscopy, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in the brain tissues were detected by colorimetry, and protein expressions of SIRT1, HIF-1α (key protein in the glycolytic pathway), glutathione peroxidase 4 (GPX4, key protein in the ferroptosis pathway), and acyl-CoA synthetase long-chain family member 4 (ACSL4, key protein in the ferroptosis pathway) were evaluated by Western blotting.Results:(1) KEGG analysis revealed that the glycolysis pathway and HIF-1 signaling pathway were obviously enriched in the cortical tissues of rats in the TBI group compared with the sham-operated group; GSEA showed that the HIF-1 signaling pathway (mmu04066) and ferroptosis pathway (mmu04216) gene sets in the cortical tissues of rats in the TBI group exhibited enrichment trends compared with those in the sham-operated group. (2) Compared with the sham-operated group, the 1-day, 3-day, and 7-day post-TBI groups had significantly decreased SIRT1 protein expression ( P<0.05), with the most prominent decline in 1-day post-TBI group. (3) Compared with the TBI+vehicle group, rats in the TBI+SIRT1 agonist group showed significantly reduced mNSS score and brain tissue water content (9.83±1.17 vs. 7.66±1.21; [83.62±0.91]% vs. [80.09±0.68]%, P<0.05). HE staining indicated clearer structure of the cortical area at the injury sites, and improved neuron morphology in the TBI+SIRT1 agonist group compared with those in the TBI+vehicle group; and transmission electron microscopy showed reduced mitochondrial shrinkage and partial restoration of cristae structures in the TBI+SIRT1 agonist group compared with those in the TBI+vehicle group. Compared with the TBI+vehicle group, the TBI+SIRT1 agonist group exhibited significantly decreased MDA content ([62.72±9.20] nmol/g vs. [39.34±3.48] nmol/g), increased SOD activity ([1.95±0.23] U/mg vs. [2.48±0.14] U/mg), elevated GPX4 protein expression (0.37±0.04 vs. 0.46±0.03), and decreased HIF-1α and ACSL4 protein expressions (1.16±0.15 vs. 0.81±0.12; 1.14±0.06 vs. 1.29±0.04), with significant differences ( P<0.05). Conclusion:SIRT1 activation can exert neuroprotective effect by inhibiting HIF-1α-mediated glycolysis and reducing neuronal ferroptosis after TBI.

Objective: To investigate the clinical, radiological, histological and molecular features and the differential diagnosis of fibrocartilaginous mesenchymoma (FM). Methods: Four cases of FM diagnosed in the Department of Pathology, the Sixth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine from 2020 to 2022 were analyzed. Related literature was also reviewed. Results: Case 1 was a 10-year-old girl with bone destruction in the sacrum and L5 articular processes revealed by CT scan. Case 2 was a 7-year-old girl with an aggressive lesion in her right distal ulna. Case 3 was an 11-year-old boy with a lesion in the metaphysis of his left proximal tibia. Case 4 was an 11-year-old boy with bone destruction in the distal portion of a radius. Microscopically, the four tumors all consisted of numerous spindle cells, hyaline cartilage nodules, and bone trabeculae. The hypocellular to moderately cellular spindle cell component contained elongated cells with slightly hyperchromatic, mildly atypical nuclei arranged in bundles or intersecting fascicles. Benign-appearing cartilaginous nodules of various sizes and shapes were scattered throughout the tumors. There were areas mimicking epiphyseal growth-plate characterized by chondrocytes arranged in parallel columns and areas of enchondral ossification. The stroma was rich in mucus in case 1. Mutation of GNAS and IDH1/IDH2 and amplification of MDM2 gene were not found in any of the three tested cases. Conclusions: FM is very rare and tends to affect young patients. It most frequently occurs in the metaphysis of long tubular bones, followed by the iliac-pubic bones and vertebrae. FM is characterized by a mixed population of spindle cells, hyaline cartilage nodules and trabeculae of bone, without specific immunophenotypes and molecular alternations. As a borderline, locally aggressive neoplasm, surgical removal with a wide margin is generally the treatment of choice for FM.
Humans ; Male ; Female ; Child ; Mesenchymoma/pathology* ; China ; Osteogenesis ; Cartilage/pathology* ; Tomography, X-Ray Computed