BACKGROUND:As an important industrial solvent,benzene can cause DNA damage,chromosome aberrence,formation of DNA adducts and gene mutation. OBJECTIVE:To explore the effects of benzene on DNA and the mechanism,as well as the changes of antioxidase system it caused. DESIGN:Randomized case control study. SETTING:The Department of Clinical Laboratory of First Affiliated Hospital and Public Health College of Harbin Medical University. PARTICIPANTS:The experiment was completed in the Animal Centre in Public Health College,Harbin Medical University.Twenty-four healthy male mice of Kunming species weighed between 18 g to 22 g were chosen.The mice were provided by Experimental Animal Centre of Second Affiliated Hospital,Harbin Medical University. INTERVENTIONS:The mice were divided into control group,low dose benzene group and high dose benzene group.Inhaling benzene smoke method was used 4 hours per day to cause benzene poisoning to mice except those of the control group.The mice were executed two months later to separate marrow cells and peripheral lymphocytes and remove liver,spleen and brain to make homogenate. MAIN OUTCOME MEASURES:Single cell gel electrophoresis (SCGE) was used to assay the DNA damages of marrow cells and peripheral lymphocytes.Meanwhile,the contents of superoxide dismulase(SOD),glutathione peroxidase(GSH-Px) and malondialdehyde(MDA) in liver,spleen and brain tissues were also detected. RESULTS:The comet percentage of marrow cells and peripheral lymphocytes in two benzene poisoning groups were(83.56± 10.28),(92.54± 15.93)% ,and(41.27± 6.03)% ,(65.79± 11.62)% respectively which were much higher than those in control group[(4.13± 0.52)% ,(2.21± 0.31)% ](P< 0.01) and represented dose-response relationship.The SOD activity of liver homogenate and GSH-Px activity of high dose and low dose groups were (11 573.31± 1 938.72),(12 574.68± 1 938.72) nkat/g and (309.40± 82.85),(375.41± 55.18) nkat/g respectively which were much lower than those in control group [(16 668.67± 3 137.96),(588.62± 110.52) nkat/g] (P< 0.05).However, there was no significant difference between different dose groups. The GSH-Px activity in spleen homogenate in two experimental groups was(421.75± 124.02) and(523.10± 45.18) nkat/g respectively which was much lower than that of control group [(618.42± 57.01) nkat/g](P< 0.05) and there was significant difference between two groups (P< 0.05).In the brain homogenate of both benzene groups,the GSH-Px activity was(87.35± 19.84) and(95.02± 14.00) nkat/g respectively which was much lower than that of control group[(118.36± 7.67) nkat/g] (P< 0.05) and without difference between two groups.The MDA content in brain homogenate of high dose group was(3.99± 1.15) μ mol/mg which was much higher than that of control group [(2.58± 0.53) μ mol/g] (P< 0.05). CONCLUSION:Chronic benzene poisoning can cause DNA impairment of marrow cells and peripheral lymphocytes and reduce the activity of antioxidase.

Objective To discuss the diagnosis effect and clinical significance of thrombelastography in chronic kidney disease. Methods From June 2016 to February 2017, two hundred and seventy non-dialysis patients with chronic kidney disease ( CKD) treated in the Fourth Hospital of Hebei Medical University were divided into non-hypercoagulable group and hypercoagulable group according to TEG comprehensive coagulation index. The changes of related clinical indexes between the two groups were analyzed and the related factors affecting the differences between the two groups were studied. Results The correlation between the two groups showed that the coagulation reaction time ( R ) , coagulation formation time ( K ) and albumin in the hypercoagulable group were significantly lower than those in the non-hypercoagulable group ((4. 69±0. 94) min vs. (6. 29±1. 63) min,(0. 93±0. 13) min vs. (1. 51±0. 58) min,(27. 54±7. 81) g/L vs. (34. 26±8. 39) g/L, P= 0. 000 ) Angle angle, maximum thrombus strength ( MA ) , fibrinogen, D-dimer, platelet count, protein/creatinine and protein content in hypercoagulable group were significantly higher than those in non-hypercoagulable group((76. 76±2. 23)°vs. (68. 19±7. 65)°;(75. 13±3. 81)mm vs. (66. 35±7. 81)mm;(4. 28 ±0. 93) g/L vs. (3. 56±1. 10) g/L ;0. 4(0. 15,0. 91) mg/L vs. 0. 22(0. 12,0. 52) mg/L;(276. 03±127. 15) ×109/L vs. (198. 18±78. 46)×109/L;5430(2579,9634) mg vs. 2620(692,5286) mg;4864(2341,7712) mg/g vs. 2557(840,5805) mg/g,P<0. 05). The differences were statistically significant. There was no significant difference in prothrombin, thromboplastin time, thrombin time, total cholesterol, triglyceride, low density lipoprotein,high density lipoprotein,creatinine between the two groups ( P>0. 05) . Correlation analysis of common clinical indicators showed that the comprehensive coagulation index ( CI) was positively correlated with Angle angle,maximum thrombus strength,fibrinogen,platelet count,protein/creatinine and protein quantification (r=0. 532,0. 522,0. 307,0. 354,0. 293,0. 216,P<0. 05),was negatively correlated with coagulation reaction time,coagulation formation time and albumin (r=- 0. 462,- 0. 496,- 0. 360,P<0. 05). Logistic regression analysis showed that platelet count, albumin and fibrinogen were the influencing factors for the grouping of comprehensive coagulation index ( OR ( 95％CI ) :1. 007 ( 1. 002-1. 013 ) , 0. 868 ( 0. 827-0. 912 ) , 1. 510 (1. 042-2. 187),P<0. 05). Conclusion TEG is a more sensitive indicator to reflect the coagulation status of patients with CKD, and has a certain guiding significance for anticoagulation treatment of patients with CKD;platelet count,albumin,fibrinogen are the factors affecting coagulation function of patients.

Objective:To investigate the clinical characteristics, surgical methods, complications and prognosis of children younger than 1 year old who had definite epileptogenic lesions under 1 year old.Methods:A total of 14 children with definite epileptogenic lesions and underwent radical surgery in Pediatric Epilepsy Center of Peking University First Hospital from March 2017 to July 2019 were selected.Their clinical data including operation age, course of disease, etiology, physical examinations, seizure types, seizure frequency, features of interictal electrocorticography(EEG), surgical methods, antiepileptic drugs, and pathology were collected and analyzed.Postoperative efficacy was eva-luated using Engel grading.The Griffiths neurodevelopmental scale and the Peabody motor developmental scale were used to assess motor neurodevelopment.Results:The operation age of 14 children was 119 to 358 days (median: 281 days), and the course of disease ranged from 119 to 352 days (median: 266 days). The age of onset was from 0 to 135 days was (median: 7.5 days), and the postoperative follow-up time was 0.5-2.0 years(median: 1.5 years). None of the patients had seizure recurrence at the last follow-up.During the follow-up period, 1 patient had recurrence, but deve-loped no seizures anymore after drug administration.Cognitive and motor functions improved during follow-up in all children.All the children had no serious complications such as postoperative infection and hydrocephalus.Conclusions:Young children with definite epileptogenic lesions have an early onset of seizures, which has a great influence on development.Multidisciplinary preoperative evaluation shows that surgery is a safe way to terminate progression of seizures, thus helping children to well develop and reducing the use of antiepileptic drugs.

Objective To optimize the method of assay for silver sulfadiazine, and to investigate its stability in high temperature, humidity and salt environment. Methods Agilent ZORBAX SB-C₁₈ column was used in HPLC for the determination of silver sulfadiazine with acetonitrile and 0.1% phosphoric acid as mobile phase.The flowing rate was 1.0 ml/min and column temperature was 30℃. Salt spray test chamber was used to simulate the high temperature, humidity and salt environment. The silver sulfadiazine content was assayed at 0, 2, 4, 6, 8, 10, 12 weeks. Results The calibration curve was linear within the range of 4.00～20.00 μg/ml (r=0.9999). The average recovery was 101.47% (RSD=2.33%). The content of silver sulfadiazine cream began to decrease significantly after 4 weeks. Conclusion This method is convenient, accurate and reliable. It can be used for the content determination of silver sulfadiazine in the cream.The results showed that the silver sulfadiazine cream was unstable in the environment of high temperature, humidity and salt. Therefore, environmental impact should be fully considered in transportation, storage and application. For the long-distance navigation mission, protective measures should be taken for its packaging or replace it with more stable products.

Objective:To investigate the characteristics of changes in muscle quality and strength in middle-aged and elderly patients with type 2 diabetes mellitus(T2DM).Methods:A total of 670 patients(320 males and 350 females)aged 50 years and over from the endocrinology departments of 9 hospitals in Beijing were recruited as the type 2 diabetes mellitus group(T2DM group)by using systematic random sampling, and 214(54 males and 75 females)age-matched Beijing Hospital retirees without T2DM were randomly enrolled as the control group.Body composition was measured by using bioimpedance analysis.Low muscle mass was defined as appendicular skeletal muscle mass index(ASMI)below 7.18 kg/m 2 in men and 5.73 kg/m 2 in women.Low muscle strength was defined as grip strength below 29.5 kg in men and 21.2 kg in women.Sarcopenia was defined by the presence of low muscle mass with low grip strength.Muscle quality was calculated by grip strength divided by muscle mass of the dominant upper limb, and muscle strength per mass unit was compared.Multivariate Logistic regression was used for correlation analysis. Results:The fasting blood glucose(FPG)level, the waist to hip ratio, the percentages of smokers and drinkers, and the proportions of subjects with concurrent hypertension and coronary heart disease were higher in the T2DM group than in the control group( P<0.05 or 0.01). Compared with the control group, grip strength and muscle quality decreased significantly in male T2DM patients( t=4.408 and 3.972, P<0.01). In male participants, BMI( t=-5.567, 95% CI: -0.375~-0.179, P<0.01)and glycated hemoglobin(HbA1c)( t=-2.322, 95% CI: -0.420~-0.035, P<0.05)were negatively correlated with muscle quality, while old age( OR=1.062, 95% CI: 1.023~1.103, P<0.01; OR=1.074, 95% CI: 1.027~1.122, P<0.01)and increased HbA1c level( OR=1.062, 95% CI: 1.023~1.103, P<0.01; OR=1.074, 95% CI: 1.027~1.122, P<0.01)were risk factors for low muscle strength and sarcopenia. Conclusions:Compared with non-diabetes patients, muscle quality and strength decrease significantly in middle-aged and elderly male T2DM patients.Besides aging, increased levels of HbA1c and BMI are risk factors for low muscle quality and strength.

Objective:To characterize the histopathological subtypes and their clinicopathological parameters of gender and onset age by common, rare and sparse primary esophageal malignant tumors (PEMT).Methods:A total of 272 437 patients with PEMT were enrolled in this study, and all of the patients were received radical surgery. The clinicopathological information of the patients was obtained from the database established by the State Key Laboratory of Esophageal Cancer Prevention & Treatment from September 1973 to December 2020, which included the clinical treatment, pathological diagnosis and follow-up information of esophagus and gastric cardia cancers. All patients were diagnosed and classified by the criteria of esophageal tumor histopathological diagnosis and classification (2019) of the World Health Organization (WHO). The esophageal tumors, which were not included in the WHO classification, were analyzed separately according to the postoperative pathological diagnosis. The χ 2 test was performed by the SPSS 25.0 software on count data, and the test standard α=0.05. Results:A total of 32 histopathological types were identified in the enrolled PEMT patients, of which 10 subtypes were not included in the WHO classification. According to the frequency, PEMT were divided into common (esophageal squamous cell carcinoma, ESCC, accounting for 97.1%), rare (esophageal adenocarcinoma, EAC, accounting for 2.3%) and sparse (mainly esophageal small cell carcinoma, malignant melanoma, etc., accounting for 0.6%). All the common, rare, and sparse types occurred predominantly in male patients, and the gender difference of rare type was most significant (EAC, male∶ female, 2.67∶1), followed with common type (ESCC, male∶ female, 1.78∶1) and sparse type (male∶ female, 1.71∶1). The common type (ESCC) mainly occurred in the middle thoracic segment (65.2%), while the rare type (EAC) mainly occurred in the lower thoracic segment (56.8%). Among the sparse type, malignant melanoma and malignant fibrous histiocytoma were both predominantly located in the lower thoracic segment (51.7%, 66.7%), and the others were mainly in the middle thoracic segment.Conclusion:ESCC is the most common type among the 32 histopathological types of PEMT, followed by EAC as the rare type, and esophageal small cell carcinoma and malignant melanoma as the major sparse type, and all of which are mainly occur in male patients. The common type of ESCC mainly occur in the middle thoracic segment, while the rare type of EAC mainly in the lower thoracic segment. The mainly sparse type of malignant melanoma and malignant fibrous histiocytoma predominately occur in the lower thoracic segment, and the remaining sparse types mainly occur in the middle thoracic segment.