The liver regenerative capacity is crucial for patients with end-stage liver disease following partial hepatectomy (PHx). The specific bacteria and mechanisms regulating liver regeneration post-PHx remain unclear. This study demonstrated dynamic changes in the abundance of Parabacteroides distasonis (P. distasonis) post-PHx, correlating with hepatocyte proliferation. Treatment with live P. distasonis significantly promoted hepatocyte proliferation and liver regeneration after PHx. Targeted metabolomics revealed a significant positive correlation between P. distasonis and β-hydroxybutyric acid (BHB), as well as hyodeoxycholic acid and 3-hydroxyphenylacetic acid in the gut after PHx. Notably, treatment with BHB, but not hyodeoxycholic acid or 3-hydroxyphenylacetic acid, significantly promoted hepatocyte proliferation and liver regeneration in mice after PHx. Moreover, STAT3 inhibitor Stattic attenuated the promotive effects of BHB on cell proliferation and liver regeneration both in vitro and in vivo. Mechanistically, P. distasonis upregulated the expression of fatty acid oxidation-related proteins, and increased BHB levels in the liver, and then BHB activated the STAT3 signaling pathway to promote liver regeneration. This study, for the first time, identifies the involvement of P. distasonis and its associated metabolite BHB in promoting liver regeneration after PHx, providing new insights for considering P. distasonis and BHB as potential strategies for promoting hepatic regeneration.

Objective·To evaluate the relationships between disc-condyle distance and anterior disc displacement,as well as between disc-condyle distance and disc morphology,in patients with temporomandibular disorders(TMD)using magnetic resonance imaging(MRI)of the temporomandibular joint(TMJ).Methods·From September 2023 to March 2024,90 patients(180 TMJs)who visited the TMJ clinic of Department of Stomatology,The Second Affiliated Hospital of Anhui Medical University,with clinical symptoms of TMD and were diagnosed via MRI with either anterior disc displacement or no significant displacement,were included.Clinical data were collected,and MRI images were used to measure the angle of disc displacement,disc-condyle distance,disc length,and thickness.The degree of disc deformation was assessed.The relationships between clinical symptoms and anterior disc displacement,between anterior disc displacement and both disc morphology and disc-condyle distance,and between disc-condyle distance and disc morphology were analyzed.Results·Among the 90 patients,there were 16 males and 74 females,with a mean age of(28.1±14.5)years.Among the 180 TMJs,175 had clinical symptoms and 5 were asymptomatic.There were 40 joints with no displacement,78 with reducible anterior disc displacement,and 62 with irreducible anterior disc displacement.In the joints with irreducible anterior disc displacement,the proportion of those with two or more symptoms was slightly higher at 62.9%,but the difference was not statistically significant compared with the joints with no displacement or reducible anterior disc displacement.MRI assessment revealed that in the joints with irreducible anterior disc displacement,the proportion of disc deformation type Ⅲ or higher was significantly higher compared with the non-displaced joints(P<0.001).The disc length was significantly shorter(P<0.001),and the intermediate zone thickness was significantly greater(P<0.001)compared with the non-displaced joints.The disc displacement angles at centric closure and maximum opening were also significantly larger(P<0.001).The disc-condyle distance was 3.10(2.70,3.70)mm for non-displaced joints,3.40(3.00,4.00)mm for joints with reducible anterior disc displacement,and 6.60(4.78,7.90)mm for joints with irreducible anterior disc displacement,with significant differences(P<0.001).The disc-condyle distance was 3.10(2.80,3.60)mm for type Ⅰ discs,3.70(3.10,4.60)mm for type Ⅱ discs,5.10(4.00,7.30)mm for type Ⅲ discs,and 6.80(4.98,8.20)mm for type Ⅳ/Ⅴ discs,with significant differences(P<0.001).The disc-condyle distance was negatively correlated with disc length(rs=-0.469,P<0.001),positively correlated with intermediate zone thickness(rs=0.319,P<0.001),and positively correlated with disc displacement angle at centric closure(rs=0.626,P<0.001).Conclusion·With increasing severity of disc deformation,intermediate zone thickness,and disc displacement angle at centric closure,as well as decreasing disc length,the disc-condyle distance increases.The disc-condyle distance is an important indicator for MRI assessment of pathological changes in TMD.

Objective:To identify independent risk factors for chronic critical illness (CCI) secondary to severe pneumonia and to develop and validate a clinical prediction model.Methods:A retrospective cohort study was conducted using electronic medical records from 415 patients with severe pneumonia admitted between January 2023 and March 2024. Patients were randomly divided into a training set ( n = 290) and a validation set ( n = 125) at a 7:3 ratio. Univariate and multivariate logistic regression analyses were used to identify independent risk factors, and a nomogram was constructed. The model’s discriminative ability, calibration, and clinical utility were assessed using receiver operating characteristic (ROC) curves, calibration plots, and decision curve analysis (DCA). Results:The overall incidence of CCI was 23.13% (96/415). Multivariate analysis identified five independent predictors: virus infection ( OR = 13.00, 95% CI: 5.07–33.35, P < 0.001), mechanical ventilation ≥72 hours ( OR = 8.06, 95% CI: 3.68–20.09, P < 0.001), neutrophil-to-albumin ratio (NAR) ( OR = 27848, 95% CI: 193.93–5542274.11, P < 0.001), oxygenation index ( OR =1.09, 95% CI: 1.01–1.09, P < 0.001), and age ( OR = 0.94, 95% CI: 0.91–0.97, P < 0.001). The model demonstrated excellent performance in both sets: training set AUC = 0.96 (95% CI: 0.94–0.98), sensitivity 0.93, specificity 0.89, Brier score 0.09; validation set AUC = 0.93 (95% CI: 0.88–0.98), sensitivity 0.89, specificity 0.64, Brier score 0.13. Calibration curves showed high consistency between predicted and observed risks (mean absolute error < 3%), and DCA indicated significant net clinical benefit within the threshold probability range of 15–60%. Conclusions:The developed prediction model integrates etiological, inflammatory, metabolic, and respiratory support parameters and demonstrates outstanding predictive performance (AUC > 0.90). It may serve as a quantitative tool for early risk stratification and intervention in patients with severe pneumonia. Further multicenter external validation and exploration of integrating dynamic biomarker monitoring are recommended.

Objective:To observe the efficacy of eculizumab in children with atypical hemolytic uremic syndrome.Methods:It was a single-center observational study. The clinical data of children diagnosed with atypical hemolytic uremic syndrome and treated with eculizumab in Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 2023 to May 2024 were retrospectively collected. Eculizumab was used at the conventional dose based on the children 's weight. Event-free survival (no death or end-stage renal disease) rate, complete remission rate and recurrence rate of thrombotic microangiopathy in children with atypical hemolytic uremic syndrome after eculizumab treatment were analyzed. The complete remission time of estimated glomerular filtration rate, hemoglobin, platelet, lactic dehydrogenase, urine routine and the adverse reactions during the treatment were observed. Whole exome sequencing was used to conduct genetic testing based on blood samples of the children and their parents.Results:There were 4 children enrolled in the study. Four children were all Han Chinese, including 3 males and 1 female. The median age of onset was 8 years (ranging from 7 to 10 years). Two patients had complement gene abnormalities, both of which were homozygous deletions of complement factor H-related 1 and complement factor H-related 3. All the patients were free of plasma exchange or perfusion after treatment with eculizumab, and the 6-month event-free survival rate and thrombotic microangiopathy complete remission rate were both 4/4. The complete remission time was 19 (14-28) days. The time for the complete recovery of platelets, lactate dehydrogenase, estimated glomerular filtration rate and hemoglobin in 4 children was 4 (1-5), 19 (14-28), 10 (5-14) and 29 (20-42) days, respectively. Except for 1 patient whose urine routine fluctuated between negative and weakly positive expression, the other 3 patients had normal urine routine. All the patients discontinued eculizumab. Two patients without gene mutations discontinued eculizumab after 7 doses, and there was no recurrence during the 1-year follow-up after drug withdrawal. Two patients with genetic abnormalities discontinued eculizumab after 26 weeks of treatment, and no recurrence was found during the 3-month follow-up after drug withdrawal. One patient developed rash approximately 7 days after receiving the third dose of eculizumab. The rash was relieved after anti-allergic treatment, and there was no recurrence after the continued use of eculizumab.Conclusion:Eculizumab is effective and safe in the treatment of children with atypical hemolytic uremic syndrome. Discontinuation of eculizumab can be considered in patients without gene mutations when their condition is stable, but close monitoring and follow-up are needed after drug withdrawal.

Objective:To investigate the risk factors for mortality in neonates with necrotizing enterocolitis (NEC).Methods:This retrospective cohort study included patients diagnosed with NEC at stage Ⅱ-Ⅲ (Bell's criteria) and admitted to the Neonatology Department of Guangzhou Women and Children's Medical Center Affiliated to Guangzhou Medical University from January 2017 to December 2022. According to the outcomes, these patients were divided into the mortality and survival groups. Perinatal conditions, clinical manifestations, disease status during hospitalization, and blood routine parameters at different time points after birth were compared between the two groups to analyze the risk factors for mortality of NEC. Statistical analysis was performed using independent-sample t-test, Mann-Whitney U test, Chi-square test (or Fisher's exact test), and multivariate logistic regression analysis. Results:(1) A total of 118 NEC cases were included, with 100 in the survival group and 18 in the mortality group. (2) The gestational age and birth weight were significantly lower in the mortality group than in the survival group [(28.9±4.2) weeks vs. (33.7±3.9) weeks, t=4.78; 940 g (685-1 275 g) vs. 1 830 g (1 352-2 368 g), Z=4.18; both P<0.05]. The incidence of neonatal asphyxia was higher in the mortality group [9/18 vs. 18% (18/100), χ2=7.13, P<0.05]. (3) Compared with the survival group, the mortality group had higher proportions of patients who were at NEC stage Ⅲ, accepted surgery, were treated with vasoactive drugs, had undergone invasive mechanical ventilation, or had metabolic acidosis, hyperlactatemia, shock, or hematochezia [17/18 vs. 24% (24/100), χ2=33.39; 17/18 vs. 31% (31/100), χ2=22.88; 16/18 vs. 22% (22/100), χ2=31.26; 16/18 vs. 39% (39/100), χ2=15.26; 18/18 vs. 28% (28/100), χ2=30.29; 16/18 vs. 20% (20/100), χ2=34.15; 17/18 vs. 21% (21/100), χ2=37.69; 9/18 vs. 82% (82/100), χ2=7.13; all P<0.05]. (4) The proportions of patients who developed late-onset sepsis, hemodynamically- significant patent ductus arteriosus, respiratory distress syndrome, or pulmonary hemorrhage were significantly higher in the mortality group than in the survival group [15/18 vs. 33% (33/100), χ2=16.01; 9/18 vs. 21% (21/100), χ2=5.32; 15/18 vs. 39% (39/100), χ2=12.08; 7/18 vs. 7% (7/100), χ2=11.94; all P<0.05]. (5) Within 24 h of birth, the levels of red blood cells and platelets were lower in the mortality group than in the survival group [4.1×1012/L (3.8×10 12/L-4.6×10 12/L) vs. 4.6×10 12/L (4.0×10 12/L-4.9×10 12/L), Z=2.04; (199.9±68.6)×10 9/L vs. (239.8±72.6)×10 9/L, t=2.16; both P<0.05]; at 6-8 d after birth, the levels of red blood cells, hemoglobin (Hb) and hematocrit (HCT) were lower in the mortality group than in the survival group [(3.2±0.5)×10 12/L vs. (3.9±0.8)×10 12/L, t=3.30; (111.2±19.2) vs. (138.1±28.3) g/L, t=3.51; (33.0±5.4)% vs. (40.9±8.1)%, t=3.61; all P<0.05]; at the diagnosis of NEC, red blood cell count, Hb level, HCT, and platelet count were lower in the mortality group than in the survival group [(3.3±1.0)×10 12/L vs. (3.8±0.8)×10 12/L, t=2.47; (102.8±28.8) vs. (124.4±26.3) g/L, t=3.59; 31.0% (25.9%-38.4%) vs. 37.2% (31.5%-43.7%), Z=2.62; 87.0×10 9/L (50.2×10 9/L-157.0×10 9/L) vs. 228.0×10 9/L (130.0×10 9/L-414.7×10 9/L), Z=3.78; all P<0.05], while mean platelet volume (MPV), platelet distribution width, and the differences in hemoglobin (ΔHb) and hematocrit (ΔHCT) between the first 24 h after birth and 6-8 d after birth were significantly higher in the mortality group than in the survival group [13.1 fl (11.4-13.6 fl) vs. 11.6 fl (10.7-12.4 fl), Z=3.26; 19.6% (13.9%-25.2%) vs. 14.8% (12.0%-18.6%), Z=2.76; 35.5 g/L (28.3-57.3 g/L) vs. 27.0 g/L (8.0-42.5 g/L), Z=2.20;11.5% (9.4%-16.3%) vs. 6.3% (2.2%-11.2%), Z=2.85; all P<0.05]. (6) Late-onset sepsis ( OR=5.568, 95% CI: 1.201-25.816), hyperlactatemia ( OR=6.702, 95% CI: 1.193-37.651), shock ( OR=10.616, 95% CI: 1.157-97.406) and MPV elevation at the diagnosis of NEC ( OR=2.769, 95% CI: 1.468-5.223) were independent risk factors, while gestational age ( OR=0.836, 95% CI: 0.708-0.986), and HCT at 6-8 d after birth ( OR=0.848, 95% CI: 0.759-0.947) were protecting fctors for death in NEC. Conclusions:Preterm infants with smaller gestational age are more prone to mortality of NEC. Early identification and management of late-onset sepsis, shock, and hyperlactatemia may reduce the risk of mortality in NEC.

Objective:To establish a pure water direct dilution-inductively coupled plasma mass spectrometry (ICP-MS) detection method for rapid determination of urinary iodine.Methods:Pure water was used to directly dilute the urine samples. The washing solution was 5.0 g/L ascorbic acid, the internal standard solution was 5.0 g/L ascorbic acid and 100 μg/L 128Te, the standard solution was prepared with the solution of lyophilized urine iodine biological component analysis reference material. The method was evaluated in terms of linear range, detection limit, quantification limit, precision and method comparision experiment. Results:The linear correlation coefficient of the standard curve for iodine concentration range from 0 to 50.0 μg/L was 0.999 7, with a detection limit of 0.2 μg/L and a quantification limit of 0.6 μg/L. The spiked recovery rates of low, medium, and high concentration iodine standard solutions added to actual urine samples were 100.8%, 99.1% and 99.7%, respectively, with relative standard deviations of 0.8%, 1.3% and 1.6%, respectively. There was no statistically significant difference ( t = - 0.14, P = 0.890) between the results of measuring actual urine and assessment urine using this method and "Determination of Iodine in Urine-Part 2: Inductively Coupled Plasma Mass Spectrometry (WS/T 107.2-2016)". Conclusions:We have successfully established a pure water direct dilution-ICP-MS method for determining urinary iodine. This method provides accurate and highly sensitive results, making it suitable for sudden public health emergencies and large-scale clinical measurement of urinary iodine.

OBJECTIVE To analyze the ethanol extracts,total phenols,total flavonoids contents and HPLC fingerprints of typi-cal propolis samples from 6 foreign countries and 5 domestic regions,optimize the extraction process and evaluate the antioxidant activi-ty,so as to provide data support for improving the quality control system of propolis.METHODS The optimization of the propolis ex-traction process utilized flavonoid content as an indicator.Three flavonoid detection methods-namely,the aluminum trichloride meth-od,aluminum nitrate method,and polyamide method-were compared.The content of ethanol extract,total phenol content,and the scavenging ability of DPPH free radicals for each sample were determined.Further analysis was conducted using HPLC fingerprint pro-filing.RESULTS The propolis extract with the highest flavonoid content was obtained using 80%ethanol as the extraction solvent,operating at 50℃,with a stirring time of 3 h,ultrasonic power of 180 W,and ultrasonic time of 15 min.The aluminum trichloride method was proved to be the most effective for determining total flavonoids in propolis.While the ethanol extract,total flavonoids,and total phenols of propolis from Xinjiang,China were relatively low,their antioxidant activity exhibited superiority.HPLC analysis re-vealed,Brazilian red propolis lacked of chrysin,galangin,caffeic acid phenethyl ester and Brazilian green propolis lacked ferulic acid,apigenin,p-coumaric acid,chrysin,and pinocembrin.In contrast,the content of these four compounds in other samples varied,with the antioxidant capacity of the extracts not precisely corresponding to the compound content.CONCLUSION Propolis exhibits a complex chemical composition with significant variations among varieties.Key quality control indexes must be comprehensively consid-ered,encompassing physicochemical characteristics and biological activity.Establishing a multi-angle assessment system with a mate-rial basis-functional linkage is essential.This approach facilitates the realization of high quality and cost-effectiveness,thereby promo-ting the healthy development of the industry.

OBJECTIVE To analyze the ethanol extracts,total phenols,total flavonoids contents and HPLC fingerprints of typi-cal propolis samples from 6 foreign countries and 5 domestic regions,optimize the extraction process and evaluate the antioxidant activi-ty,so as to provide data support for improving the quality control system of propolis.METHODS The optimization of the propolis ex-traction process utilized flavonoid content as an indicator.Three flavonoid detection methods-namely,the aluminum trichloride meth-od,aluminum nitrate method,and polyamide method-were compared.The content of ethanol extract,total phenol content,and the scavenging ability of DPPH free radicals for each sample were determined.Further analysis was conducted using HPLC fingerprint pro-filing.RESULTS The propolis extract with the highest flavonoid content was obtained using 80%ethanol as the extraction solvent,operating at 50℃,with a stirring time of 3 h,ultrasonic power of 180 W,and ultrasonic time of 15 min.The aluminum trichloride method was proved to be the most effective for determining total flavonoids in propolis.While the ethanol extract,total flavonoids,and total phenols of propolis from Xinjiang,China were relatively low,their antioxidant activity exhibited superiority.HPLC analysis re-vealed,Brazilian red propolis lacked of chrysin,galangin,caffeic acid phenethyl ester and Brazilian green propolis lacked ferulic acid,apigenin,p-coumaric acid,chrysin,and pinocembrin.In contrast,the content of these four compounds in other samples varied,with the antioxidant capacity of the extracts not precisely corresponding to the compound content.CONCLUSION Propolis exhibits a complex chemical composition with significant variations among varieties.Key quality control indexes must be comprehensively consid-ered,encompassing physicochemical characteristics and biological activity.Establishing a multi-angle assessment system with a mate-rial basis-functional linkage is essential.This approach facilitates the realization of high quality and cost-effectiveness,thereby promo-ting the healthy development of the industry.

Objective:To investigate the risk factors for mortality in neonates with necrotizing enterocolitis (NEC).Methods:This retrospective cohort study included patients diagnosed with NEC at stage Ⅱ-Ⅲ (Bell's criteria) and admitted to the Neonatology Department of Guangzhou Women and Children's Medical Center Affiliated to Guangzhou Medical University from January 2017 to December 2022. According to the outcomes, these patients were divided into the mortality and survival groups. Perinatal conditions, clinical manifestations, disease status during hospitalization, and blood routine parameters at different time points after birth were compared between the two groups to analyze the risk factors for mortality of NEC. Statistical analysis was performed using independent-sample t-test, Mann-Whitney U test, Chi-square test (or Fisher's exact test), and multivariate logistic regression analysis. Results:(1) A total of 118 NEC cases were included, with 100 in the survival group and 18 in the mortality group. (2) The gestational age and birth weight were significantly lower in the mortality group than in the survival group [(28.9±4.2) weeks vs. (33.7±3.9) weeks, t=4.78; 940 g (685-1 275 g) vs. 1 830 g (1 352-2 368 g), Z=4.18; both P<0.05]. The incidence of neonatal asphyxia was higher in the mortality group [9/18 vs. 18% (18/100), χ2=7.13, P<0.05]. (3) Compared with the survival group, the mortality group had higher proportions of patients who were at NEC stage Ⅲ, accepted surgery, were treated with vasoactive drugs, had undergone invasive mechanical ventilation, or had metabolic acidosis, hyperlactatemia, shock, or hematochezia [17/18 vs. 24% (24/100), χ2=33.39; 17/18 vs. 31% (31/100), χ2=22.88; 16/18 vs. 22% (22/100), χ2=31.26; 16/18 vs. 39% (39/100), χ2=15.26; 18/18 vs. 28% (28/100), χ2=30.29; 16/18 vs. 20% (20/100), χ2=34.15; 17/18 vs. 21% (21/100), χ2=37.69; 9/18 vs. 82% (82/100), χ2=7.13; all P<0.05]. (4) The proportions of patients who developed late-onset sepsis, hemodynamically- significant patent ductus arteriosus, respiratory distress syndrome, or pulmonary hemorrhage were significantly higher in the mortality group than in the survival group [15/18 vs. 33% (33/100), χ2=16.01; 9/18 vs. 21% (21/100), χ2=5.32; 15/18 vs. 39% (39/100), χ2=12.08; 7/18 vs. 7% (7/100), χ2=11.94; all P<0.05]. (5) Within 24 h of birth, the levels of red blood cells and platelets were lower in the mortality group than in the survival group [4.1×1012/L (3.8×10 12/L-4.6×10 12/L) vs. 4.6×10 12/L (4.0×10 12/L-4.9×10 12/L), Z=2.04; (199.9±68.6)×10 9/L vs. (239.8±72.6)×10 9/L, t=2.16; both P<0.05]; at 6-8 d after birth, the levels of red blood cells, hemoglobin (Hb) and hematocrit (HCT) were lower in the mortality group than in the survival group [(3.2±0.5)×10 12/L vs. (3.9±0.8)×10 12/L, t=3.30; (111.2±19.2) vs. (138.1±28.3) g/L, t=3.51; (33.0±5.4)% vs. (40.9±8.1)%, t=3.61; all P<0.05]; at the diagnosis of NEC, red blood cell count, Hb level, HCT, and platelet count were lower in the mortality group than in the survival group [(3.3±1.0)×10 12/L vs. (3.8±0.8)×10 12/L, t=2.47; (102.8±28.8) vs. (124.4±26.3) g/L, t=3.59; 31.0% (25.9%-38.4%) vs. 37.2% (31.5%-43.7%), Z=2.62; 87.0×10 9/L (50.2×10 9/L-157.0×10 9/L) vs. 228.0×10 9/L (130.0×10 9/L-414.7×10 9/L), Z=3.78; all P<0.05], while mean platelet volume (MPV), platelet distribution width, and the differences in hemoglobin (ΔHb) and hematocrit (ΔHCT) between the first 24 h after birth and 6-8 d after birth were significantly higher in the mortality group than in the survival group [13.1 fl (11.4-13.6 fl) vs. 11.6 fl (10.7-12.4 fl), Z=3.26; 19.6% (13.9%-25.2%) vs. 14.8% (12.0%-18.6%), Z=2.76; 35.5 g/L (28.3-57.3 g/L) vs. 27.0 g/L (8.0-42.5 g/L), Z=2.20;11.5% (9.4%-16.3%) vs. 6.3% (2.2%-11.2%), Z=2.85; all P<0.05]. (6) Late-onset sepsis ( OR=5.568, 95% CI: 1.201-25.816), hyperlactatemia ( OR=6.702, 95% CI: 1.193-37.651), shock ( OR=10.616, 95% CI: 1.157-97.406) and MPV elevation at the diagnosis of NEC ( OR=2.769, 95% CI: 1.468-5.223) were independent risk factors, while gestational age ( OR=0.836, 95% CI: 0.708-0.986), and HCT at 6-8 d after birth ( OR=0.848, 95% CI: 0.759-0.947) were protecting fctors for death in NEC. Conclusions:Preterm infants with smaller gestational age are more prone to mortality of NEC. Early identification and management of late-onset sepsis, shock, and hyperlactatemia may reduce the risk of mortality in NEC.

Objective·To evaluate the relationships between disc-condyle distance and anterior disc displacement,as well as between disc-condyle distance and disc morphology,in patients with temporomandibular disorders(TMD)using magnetic resonance imaging(MRI)of the temporomandibular joint(TMJ).Methods·From September 2023 to March 2024,90 patients(180 TMJs)who visited the TMJ clinic of Department of Stomatology,The Second Affiliated Hospital of Anhui Medical University,with clinical symptoms of TMD and were diagnosed via MRI with either anterior disc displacement or no significant displacement,were included.Clinical data were collected,and MRI images were used to measure the angle of disc displacement,disc-condyle distance,disc length,and thickness.The degree of disc deformation was assessed.The relationships between clinical symptoms and anterior disc displacement,between anterior disc displacement and both disc morphology and disc-condyle distance,and between disc-condyle distance and disc morphology were analyzed.Results·Among the 90 patients,there were 16 males and 74 females,with a mean age of(28.1±14.5)years.Among the 180 TMJs,175 had clinical symptoms and 5 were asymptomatic.There were 40 joints with no displacement,78 with reducible anterior disc displacement,and 62 with irreducible anterior disc displacement.In the joints with irreducible anterior disc displacement,the proportion of those with two or more symptoms was slightly higher at 62.9%,but the difference was not statistically significant compared with the joints with no displacement or reducible anterior disc displacement.MRI assessment revealed that in the joints with irreducible anterior disc displacement,the proportion of disc deformation type Ⅲ or higher was significantly higher compared with the non-displaced joints(P<0.001).The disc length was significantly shorter(P<0.001),and the intermediate zone thickness was significantly greater(P<0.001)compared with the non-displaced joints.The disc displacement angles at centric closure and maximum opening were also significantly larger(P<0.001).The disc-condyle distance was 3.10(2.70,3.70)mm for non-displaced joints,3.40(3.00,4.00)mm for joints with reducible anterior disc displacement,and 6.60(4.78,7.90)mm for joints with irreducible anterior disc displacement,with significant differences(P<0.001).The disc-condyle distance was 3.10(2.80,3.60)mm for type Ⅰ discs,3.70(3.10,4.60)mm for type Ⅱ discs,5.10(4.00,7.30)mm for type Ⅲ discs,and 6.80(4.98,8.20)mm for type Ⅳ/Ⅴ discs,with significant differences(P<0.001).The disc-condyle distance was negatively correlated with disc length(rs=-0.469,P<0.001),positively correlated with intermediate zone thickness(rs=0.319,P<0.001),and positively correlated with disc displacement angle at centric closure(rs=0.626,P<0.001).Conclusion·With increasing severity of disc deformation,intermediate zone thickness,and disc displacement angle at centric closure,as well as decreasing disc length,the disc-condyle distance increases.The disc-condyle distance is an important indicator for MRI assessment of pathological changes in TMD.