Objective:To analyze the status of anemia at the beginning of dialysis in maintenance hemodialysis (MHD) adult patients, and to explore the relationship between early dialysis anemia and early survival and long-term survival.Methods:It was a retrospective cohort study. The baseline demographic and clinical data of newly admitted MHD patients from January 1, 2013 to December 31, 2020 were retrospectively analyzed. According to the hemoglobin (Hb) level at the beginning of dialysis, the patients were divided into high Hb group (Hb≥110 g/L), middle Hb group (80 g/L≤Hb<110 g/L) and low Hb group (Hb<80 g/L). The baseline data among the three groups were compared, and the changing trend of Hb level in MHD patients during the 8 years was analyzed. The follow-up ended at peritoneal dialysis, kidney transplantation, death or on December 31, 2021. All-cause death event within 6 months after the initiation of dialysis was defined as early death, while all-cause death event more than 6 months after the initiation of dialysis was defined as long-term death. Kaplan-Meier survival curve was used to analyze the survival rate, and log-rank test was used to compare the survival rates among the three groups. Multivariate Cox regression analysis model was used to analyze the association between anemia (Hb<110 g/L) at the beginning of dialysis and both early and long-term mortality.Results:A total of 36 216 MHD patients were included in this study, with age of (61.3±15.5) years old and 22 163 males (61.20%). The Hb at the beginning of dialysis was (89.33±20.89) g/L. The compliance rate of Hb (≥110 g/L) was 16.43% (5 952/36 216). There were 12 232 patients (33.78%), 18 032 patients (49.79%), and 5 952 patients (16.43%) in low Hb group, middle Hb group, and high Hb group, respectively. There were statistically significant differences in gender distribution, age, serum creatinine, blood phosphorus, blood calcium, C-reactive protein, intact parathyroid hormone, blood leukocytes, platelets, serum albumin, triglyceride, total cholesterol, and proportions of chronic glomerulonephritis, diabetic nephropathy, diabetes mellitus, cardiovascular and cerebrovascular diseases, tumors, emporary catheter, long-term catheter and autologous arteriovenous fistula among the three groups (all P<0.05). During the 8-year period, the Hb level had an increased trend steadily each year, and Hb was (88.48±22.07) g/L, (88.52±21.43) g/L, (87.86±21.29) g/L, (88.93±20.69) g/L, (88.87±20.69) g/L, (90.03±20.47) g/L, (90.74±20.31) g/L and (90.31±20.54) g/L year by year. There were 2 176 early deaths (6.01%), and 6 557 long-term deaths (18.10%) by the end of follow-up. Kaplan-Meier survival curve showed that early survival rate of low Hb group was significantly lower than those of high Hb group (log-rank test, χ2=57.115, P<0.001) and middle Hb group (log-rank test, χ2=49.918, P<0.001), and long-term survival rates of low Hb group (log-rank test, χ2=107.097, P<0.001) and middle Hb group (log-rank test, χ2=47.430, P<0.001) were significantly lower than that of high Hb group. Multivariate Cox regression analysis showed that Hb<80 g/L at the beginning of dialysis was an independent influencing factor of early death (Hb ≥110 g/L as a reference, HR=1.307, 95% CI 1.096-1.559), and 80 g/L≤Hb<110 g/L and Hb<80 g/L at the beginning of dialysis were the independent influencing factors of long-term death (Hb≥110 g/L as a reference, HR=1.108, 95% CI 1.021-1.203; HR=1.228, 95% CI 1.127-1.339, respectively) in MHD patients. Conclusions:The compliance rate of Hb at the beginning of dialysis in MHD patients is low. Hb <80 g/L at the beginning of dialysis is an independent risk factor of early death, and Hb <110 g/L at the beginning of dialysis is an independent risk factor of long-term death in MHD patients.

BACKGROUND:Mesenchymal stem cell-derived exosomes may play a crucial role in tissue damage repair,and miRNA is an important component of exosomes for therapeutic effects.Among them,miR-29b-3p has the effect of reducing cell apoptosis,promoting axonal regeneration,and angiogenesis. OBJECTIVE:To study the protective effect of adipose-derived mesenchymal stem cell-derived exosome via miR-29b-3p on a neural cell injury model simulated by H2O2-treated PC12 cells,and explore the relevant mechanisms. METHODS:(1)First,the collagenase digestion method was used to extract rat adipose-derived mesenchymal stem cells.Adipose-derived mesenchymal stem cells were transfected with miR-29b-3p mimics and inhibitors.Exosomes were extracted from the culture supernatant by ultracentrifugation and identified so as to construct adipose-derived mesenchymal stem cell-derived exosomes with high expression and knockdown miR-29b-3p.(2)By constructing a neural cell injury model simulated by PC12 cells treated with H2O2,the relevant mechanisms of the protective effect of adipose-derived mesenchymal stem cell-derived exosome via miR-29b-3p on the simulated neuronal cell injury model were studied. RESULTS AND CONCLUSION:(1)Adipose-derived mesenchymal stem cell-derived exosome had a typical cup-shaped shape and a diameter distribution in the range of 50-140 nm,expressed membrane proteins Alix,CD63,and TSG101,which were specific markers on the surface of exosomes,and could be successfully ingested by PC12 cells.(2)Adipose-derived mesenchymal stem cell-derived exosome pretreatment could reduce cell apoptosis induced by H2O2 treatment in PC12 cells,and this protective effect was enhanced with the increase of miR-29b-3p expression in the exosomes and weakened with the decrease of miR-29b-3p expression in the exosomes.The mechanism of its effect was related to adipose-derived mesenchymal stem cell-derived exosome via miR-29b-3p promoting the expression of anti-apoptotic protein Bcl-2 and inhibiting the expression of apoptotic protein Bax.

Objective:To investigate the early warning value of transcutaneous oxygen pressure and transcutaneous carbon dioxide pressure (TcPO 2/TcPCO 2) monitoring in patients with pressure injury in ICU. Methods:A prospective clinical observation study was conducted. Patients were selected in the department of critical care medicine of Shenzhen Hospital Affiliated to University of Chinese Academy of Sciences from December 2020 to June 2022. The general information of all patients were recorded. The data of TcPO 2 and TcPCO 2 were monitored respectively in left lying position, supine position and right lying position. According to the Braden score of patients, they were divided into low risk group and high risk group, and the monitoring results of TcPO 2/TcPCO 2 were analyzed. Results:The study included a total of 80 patients, with 46 patients in the low risk group and 34 patients in the high risk group. There were no significant differences in gender and age between the two groups (both P>0.05). There were significant differences in the Braden score and the incidence of pressure injury between the two groups (both P<0.05). There were statistically significant differences in TcPO 2 at various time points in the left lying position, supine position and right lying position between the low risk and the high risk groups (all P<0.001). Except for the 15th minute of the left lying position and right lying position, there were statistically significant differences in TcPCO2 at all other time points in the supine and right lying positions between two groups (all P<0.05). There were statistically significant differences in TcPO 2/TcPCO 2 values at various time points in different positions between two groups (all P<0.001). In supine position, TcPO 2 and TcPO 2/TcPCO 2 were positively correlated with the Braden score ( r=0.680, 0.741). TcPCO 2 was negatively correlated with the Braden score ( r=-0.771). The Braden score, TcPO 2, TcPCO 2 and TcPO 2/TcPCO 2 all have moderate diagnostic value. The cut-off values were 12.50, 41.48 mmHg, 52.29 mmHg and 0.91, respectively. And the AUC were 0.899, 0.727, 0.816 and 0.719, respectively. However, there were no significant differences in AUC between the TcPO 2, TcPCO 2, TcPO 2/TcPCO 2 and Braden score (all P>0.05). Conclusions:TcPO 2, TcPCO 2 and TcPO 2/TcPCO 2 values all have higher diagnostic value about pressure injury for patients in ICU. TcPO 2/TcPCO 2 monitoring has early risk warning value for the occurrence of pressure injury in ICU, which is worthy of clinical promotion.

Objective:To analyze the EGFR mutation profile of lung cancer patients in Yunnan, and to provide evidence for clinical personalized treatment.Methods:Demographic and clinical data of 2 967 lung cancer patients undergoing EGFR identification were collected and analyzed from January 2014 to August 2019 in Yunnan Cancer Hospital.Results:The proportion of EGFR mutation in 2 967 patients with lung cancer was 46.2%. Univariate analysis showed that the proportion of EGFR mutation in women was higher than that in men ( P<0.001) and displayed a downward trend with age ( P=0.03). The mutation rate of ethnic minorities was higher than Han ( P=0.012). Mutation rate in patients without smoking history was higher than those with smoking history ( P<0.001), and patients without drinking history was higher than patients with drinking history ( P<0.001). Mutation rate in patients without family history of lung cancer was higher than those with family history ( P=0.008). The mutation rate of adenocarcinoma was higher than other pathological types ( P<0.001). The mutation rate was different among stages, and it was higher in early patients than that in advanced patients ( P<0.001). The mutation rate of tissue specimens was higher than those of cytology and peripheral blood samples ( P<0.001). The mutation rate of Xuanwei area was lower than that in non-Xuanwei area ( P<0.001). Multivariate analysis showed that gender ( P<0.001), age ( P=0.036), smoking history ( P<0.001), pathological type ( P<0.001), specimen type ( P<0.001), and whether or not Xuanwei area ( P<0.001) were the independent factors of EGFR mutation.The EGFR mutation was more common in female, non-smokers, adenocarcinoma, non-Xuanwei area, tissue specimen and young lung cancer patients.The mutation types of EGFR in 1 370 cases mainly included 19-Del and L858R. The predominant mutation of EGFR in Xuanwei area was L858R, while in non-Xuanwei area was 19-Del.The mutation rates of G719X, G719X+ L861Q, G719X+ S768I, and S768I in Xuanwei were higher while the mutation rates of 19-Del, L858R, and 20-ins were lower than non-Xuanwei area ( P<0.05). The 19-Del mutation rate of ethnic minorities is higher than that of Han ( P<0.001). The combined mutation rate of G719X, L861Q in Han was higher than that of ethnic minorities ( P=0.005). Conclusions:The EGFR mutation rate in lung cancer patients in Yunnan is similar to Asian and Chinese, and higher in female, non-smokers, adenocarcinomas, young and non-Xuanwei area patients. The most common types of EGFR mutation in Yunnan are 19-Del and L858R. The predominant mutation of EGFR in Xuanwei area is L858R, while in non-Xuanwei area is 19-Del. The mutation rates of G719X, G719X+ L861Q, G719X+ S768I and S768I are higher in Xuanwei patients than those in non-Xuanwei patients. The combined mutation rate of G719X and L861Q in Han nationality is higher than that of ethnic minorities.

Objective:To analyze the expressions of non-small-cell lung cancer (NSCLC) driver genes and their mutation distribution characteristics in the Yunnan-Kweichow plateau, and to provide evidences for personalized molecular targeted therapy of lung cancer in high-incidence areas.Methods:A retrospective analysis was performed on the medical records of patients with NSCLC who underwent combined lung cancer 8 gene detection, including epidermal growth factor receptor (EGFR), rat sarcoma viral oncogene (RAS), anaplastic lymphoma kinase (ALK), RET proto-oncogene (RET), v-Raf murine sarcoma viral oncogene homolog (BRAF), ROS proto-oncogene 1 (ROS1), human epidermal growth factor receptor-2 (HER-2), and cellular-mesenchymal to epithelial transition factor (MET), from January 2016 to August 2019 in Yunnan Cancer Hospital. Besides, we analyzed the expressions of NSCLC driver genes and their mutation distributions.Results:The positive rate of NSCLC driver genes in Yunnan was 67.05%(1 508/2 249). The mutation rates in Xishuangbanna (76.92%), Yuxi (72.38%), Xuanwei (71.88%), Qujing (71.24%), and Honghe (71.79%) were significantly higher than other areas. The mutation rates of Hui (84.38%), Hani (85.00%), Zhuang (75.00%), Buyi (100%), Manchu (100%), Tujia (100%) and Achang (100%) are significantly higher than the minority national average. Driver gene mutations were related to gender ( P<0.001), smoking history ( P<0.001), age ( P<0.001), pathological type ( P<0.001), and whether the Xuanwei area ( P=0.027), but not related to the nationality ( P=0.748) and family history of lung cancer ( P=0.676). The mutation rates of EGFR, RAS, BRAF, HER-2 and MET genes were 44.46%, 10.98%, 1.24%, 0.89% and 0.76%, and the rearrangement rates of ALK, RET and ROS1 genes were 4.67%, 1.29% and 0.89%, respectively.The mutation rate of EGFR in females was 56.67%, which was higher than 33.19% in males ( P<0.001). The mutation rate of RAS in males was 12.66%, which was higher than 9.17% in females ( P=0.010). The mutation rate of RAS in the Han was 11.49%, which was higher than 7.17% in the minority ( P=0.032). The rate of RAS mutation in Xuanwei patients was 24.74%, significantly higher than 8.15% in non-Xuanwei area ( P<0.001), and the EGFR mutation rate was 40.63%, which was lower than 45.25% in non-Xuanwei area ( P=0.045). The rate of ALK rearrangement in Xuanwei patients was 1.56%, which was significantly lower than 5.31% in the non-Xuanwei area ( P<0.001), and no HER-2 mutation patients were detected in Xuanwei area. The mutation rate of EGFR in patients with non-smoking history was 51.10%, significantly higher than 29.70% of patients with smoking history ( P<0.001). Meanwhile, the rate of ALK rearrangement with non-smoking history patients was 5.35%, which was also higher than 3.16% of patients with smoking history ( P<0.001). The rate of RAS mutation in patients with non-smoking history was 9.34%, lower than 14.63% of patients with smoking history ( P=0.008). Conclusions:The positive rate of driven gene expression in NSCLC patients from the Yunnan-Kweichow Plateau is slightly lower than the national average. The rates of EGFR and RAS mutations are similar to the domestic average. The rates of ROS1, ALK and RET genes rearrangements and the rates of BRAF, HER2 and MET gene mutations are slightly lower than the national average. EGFR, RAS and ALK genes in the NSCLC patients from Yunnan-Kweichow Plateau have high positive rates, and display different demographic and clinical characteristics, which are of great significance in the selection of targeted therapy populations.

Objective:To analyze the EGFR mutation profile of lung cancer patients in Yunnan, and to provide evidence for clinical personalized treatment.Methods:Demographic and clinical data of 2 967 lung cancer patients undergoing EGFR identification were collected and analyzed from January 2014 to August 2019 in Yunnan Cancer Hospital.Results:The proportion of EGFR mutation in 2 967 patients with lung cancer was 46.2%. Univariate analysis showed that the proportion of EGFR mutation in women was higher than that in men ( P<0.001) and displayed a downward trend with age ( P=0.03). The mutation rate of ethnic minorities was higher than Han ( P=0.012). Mutation rate in patients without smoking history was higher than those with smoking history ( P<0.001), and patients without drinking history was higher than patients with drinking history ( P<0.001). Mutation rate in patients without family history of lung cancer was higher than those with family history ( P=0.008). The mutation rate of adenocarcinoma was higher than other pathological types ( P<0.001). The mutation rate was different among stages, and it was higher in early patients than that in advanced patients ( P<0.001). The mutation rate of tissue specimens was higher than those of cytology and peripheral blood samples ( P<0.001). The mutation rate of Xuanwei area was lower than that in non-Xuanwei area ( P<0.001). Multivariate analysis showed that gender ( P<0.001), age ( P=0.036), smoking history ( P<0.001), pathological type ( P<0.001), specimen type ( P<0.001), and whether or not Xuanwei area ( P<0.001) were the independent factors of EGFR mutation.The EGFR mutation was more common in female, non-smokers, adenocarcinoma, non-Xuanwei area, tissue specimen and young lung cancer patients.The mutation types of EGFR in 1 370 cases mainly included 19-Del and L858R. The predominant mutation of EGFR in Xuanwei area was L858R, while in non-Xuanwei area was 19-Del.The mutation rates of G719X, G719X+ L861Q, G719X+ S768I, and S768I in Xuanwei were higher while the mutation rates of 19-Del, L858R, and 20-ins were lower than non-Xuanwei area ( P<0.05). The 19-Del mutation rate of ethnic minorities is higher than that of Han ( P<0.001). The combined mutation rate of G719X, L861Q in Han was higher than that of ethnic minorities ( P=0.005). Conclusions:The EGFR mutation rate in lung cancer patients in Yunnan is similar to Asian and Chinese, and higher in female, non-smokers, adenocarcinomas, young and non-Xuanwei area patients. The most common types of EGFR mutation in Yunnan are 19-Del and L858R. The predominant mutation of EGFR in Xuanwei area is L858R, while in non-Xuanwei area is 19-Del. The mutation rates of G719X, G719X+ L861Q, G719X+ S768I and S768I are higher in Xuanwei patients than those in non-Xuanwei patients. The combined mutation rate of G719X and L861Q in Han nationality is higher than that of ethnic minorities.

Objective:To analyze the expressions of non-small-cell lung cancer (NSCLC) driver genes and their mutation distribution characteristics in the Yunnan-Kweichow plateau, and to provide evidences for personalized molecular targeted therapy of lung cancer in high-incidence areas.Methods:A retrospective analysis was performed on the medical records of patients with NSCLC who underwent combined lung cancer 8 gene detection, including epidermal growth factor receptor (EGFR), rat sarcoma viral oncogene (RAS), anaplastic lymphoma kinase (ALK), RET proto-oncogene (RET), v-Raf murine sarcoma viral oncogene homolog (BRAF), ROS proto-oncogene 1 (ROS1), human epidermal growth factor receptor-2 (HER-2), and cellular-mesenchymal to epithelial transition factor (MET), from January 2016 to August 2019 in Yunnan Cancer Hospital. Besides, we analyzed the expressions of NSCLC driver genes and their mutation distributions.Results:The positive rate of NSCLC driver genes in Yunnan was 67.05%(1 508/2 249). The mutation rates in Xishuangbanna (76.92%), Yuxi (72.38%), Xuanwei (71.88%), Qujing (71.24%), and Honghe (71.79%) were significantly higher than other areas. The mutation rates of Hui (84.38%), Hani (85.00%), Zhuang (75.00%), Buyi (100%), Manchu (100%), Tujia (100%) and Achang (100%) are significantly higher than the minority national average. Driver gene mutations were related to gender ( P<0.001), smoking history ( P<0.001), age ( P<0.001), pathological type ( P<0.001), and whether the Xuanwei area ( P=0.027), but not related to the nationality ( P=0.748) and family history of lung cancer ( P=0.676). The mutation rates of EGFR, RAS, BRAF, HER-2 and MET genes were 44.46%, 10.98%, 1.24%, 0.89% and 0.76%, and the rearrangement rates of ALK, RET and ROS1 genes were 4.67%, 1.29% and 0.89%, respectively.The mutation rate of EGFR in females was 56.67%, which was higher than 33.19% in males ( P<0.001). The mutation rate of RAS in males was 12.66%, which was higher than 9.17% in females ( P=0.010). The mutation rate of RAS in the Han was 11.49%, which was higher than 7.17% in the minority ( P=0.032). The rate of RAS mutation in Xuanwei patients was 24.74%, significantly higher than 8.15% in non-Xuanwei area ( P<0.001), and the EGFR mutation rate was 40.63%, which was lower than 45.25% in non-Xuanwei area ( P=0.045). The rate of ALK rearrangement in Xuanwei patients was 1.56%, which was significantly lower than 5.31% in the non-Xuanwei area ( P<0.001), and no HER-2 mutation patients were detected in Xuanwei area. The mutation rate of EGFR in patients with non-smoking history was 51.10%, significantly higher than 29.70% of patients with smoking history ( P<0.001). Meanwhile, the rate of ALK rearrangement with non-smoking history patients was 5.35%, which was also higher than 3.16% of patients with smoking history ( P<0.001). The rate of RAS mutation in patients with non-smoking history was 9.34%, lower than 14.63% of patients with smoking history ( P=0.008). Conclusions:The positive rate of driven gene expression in NSCLC patients from the Yunnan-Kweichow Plateau is slightly lower than the national average. The rates of EGFR and RAS mutations are similar to the domestic average. The rates of ROS1, ALK and RET genes rearrangements and the rates of BRAF, HER2 and MET gene mutations are slightly lower than the national average. EGFR, RAS and ALK genes in the NSCLC patients from Yunnan-Kweichow Plateau have high positive rates, and display different demographic and clinical characteristics, which are of great significance in the selection of targeted therapy populations.

Objective: To explore the recovery time and risk factors of coagulopathy caused by rodenticide poisoning through analyzing and following up the confirmed cases, and to provide more useful guidance information for the clinic practice. Methods: A total of 96 cases with coagulation dysfunction caused by anticoagulant rodenticide poiso-ning in Children′s Hospital, Chongqing Medical University from January 2014 to December 2016, were analyzed retrospectively.The recovery time of coagulation function and the relationship between recovery time and drug involved way, dysfunction organs and poison concentration were studied respectively. Results: (1) A total of 96 patients were hospitalized because of severe coagulopathy caused by the poisoning of second generation anticoagulant rodenticide.Brodifacoum was detected from 33 blood samples and the median concentration was 364 μg/L (55-4 654 μg/L). Bromadiolone was detected from 7 blood samples and the median concentration was 130 μg/L (18-652 μg/L). Brodifacoum and Bromadiolone were both detected from 8 cases and the median concentration was 741 μg/L (63-6 000 μg/L) and 11 μg/L (3-3 694 μg/L), respectively.(2) A total of 57 cases of the patients were successfully followed up.A total of 18 cases were confirmed with oral poisoning, 16 cases with dermal poisoning, while 23 cases denied any involved ways of poisoning, and 7 cases had organs dysfunction.The follow-up time was 12-54 months.All the hospitalized patients were given specific antidote Vitamin K treatment and recovered successfully without any sequelae.(3) The median recovery time of coagulopathy caused by rodenticide poisoning was 2.5 months.(4) The recovery time of coagulation function was positively correlated with the plasma concentration of Brodifacoum(r=0.619, P<0.01). (5) There was no significant correlation between recovery time and organ dysfunction or drug involved ways of poisoning involvement (all P>0.05). Conclusions The recovery time of coagulation dysfunction caused by anticoagulant rodenticide in children is much longer.The higher the concentration of Brodifacoum poison is, the longer the recovery time.Enough supplementation course of Vitamin K should be given according to the follow-up of coagulation function.

Objective: To detect the mutation of epidermal growth factor receptor (EGFR) gene in peripheral blood of non-small cell lung cancer (NSCLC) patients in Yunnan area with Super-ARMS, and to explore its correlation with clinicopathological characteristics. Methods: A total of 222 blood samples from patients with NSCLC were collected between January 2017 to December 2018 in the Molecular Diagnostic Center of Yunnan Cancer Hospital. The EGFR gene mutation in peripheral blood samples was detected by SuperARMS, and the relationship between EGFR gene mutation and clinicopathological features was analyzed. Meanwhile, the independent risk factors influencing EFGR mutation were also analyzed. Results: In the peripheral blood of 222 NSCLC patients, there were 81 cases (36.5%) with EGFR gene mutation. Among them, exon 19 deletion and L858R gene point mutation were the most common (75.3% of total mutation); female patients had a higher mutation rate than male patients (45.9% vs 27.0%); patients <60 years old had a higher incidence of mutation than patients≥60 years old (43.2% vs 28.8%) (P<0.05 or P<0.01); moreover, patients with no history of smoking, no history of radical surgery, adenocarcinoma, advanced stage and no history of chemotherapy had higher incidence of EGFR mutation (43.9% vs 21.6%, 39.2% vs 21.2%, 43.9% vs 4.8%, 39.7% vs 23.3% and 44.0% vs 23.5%) (P<0.05 or P<0.01). Multivariate logistic analysis showed that young, no smoking history, adenocarcinoma and no surgical history were independent risk factors for EGFR gene mutation (all P<0.01). Conclusion: In the peripheral blood of patients with NSCLC in Yunnan, the mutation rate of EGFR gene is higher in patients with age<60 years old, adenocarcinoma and non-smoking. Super-ARMS method is more sensitive in the detection of EGFR mutation in peripheral blood of lung cancer patients.

Objective : To study the anatomical characteristics of the root and root canal system of the mandibular second permanent molar in the Uygur people and provide a reference for clinical practice. Methods : A total of 125 mandibular second permanent molars were extracted from Uygur patients in hospitals in the Xinjiang Uygur Autonomous Region. Three-dimensional reconstruction was performed after micro-CT scanning. The number of root canals, the root canal type (Weine classification and Fan′s C-shaped canal classification) and the occurrence of lateral accessory canals were observed. Results : A sex difference was not detected in the root number or root form (χ2 = 1.277, P = 0.259). The incidence of 2-rooted molars was 70.4% (n = 88); type 2-1 canals were most common in the mesial root, with an incidence of 29.5%, followed by type 1-1 and 2-2 canals (each with an incidence of 26.1%), and the distal root mostly had a type 1-1 canal (96.6%). The incidence of single-rooted molars was 28.8%, and the frequency of C-shaped (n = 28) and non-C-shaped (n = 8) single-rooted molars was 22.4% and 6.4%, respectively. A three-rooted molar was detected in one case. The incidence of accessory canals was 65.2%. Conclusion Uygur mandibular second molars are mainly composed of two roots, and the incidence of a single root and root canal fusion is low (including C-shaped canals). Two-rooted molars frequently have two mesial canals and one distal canal.