1.A preliminary investigation study of islet function assessment
Wenxuan BIAN ; Yunqiang HE ; Qi FU ; Shuang CHEN ; Min SUN ; Tao YANG
Chinese Journal of Diabetes 2024;32(3):161-168
		                        		
		                        			
		                        			Objective To investigate doctors'knowledge and differences in islet function assessment methods in China.Methods This is a cross-sectional study that conducted by online questionnaire survey.Demographic data,examination items,blood collection point of OGTT,detection method,kit type and follow-up frequency were collected and compared among doctors in different regions,different levels of hospitals,different specialties and different titles.Results 79.2%and 85.1%of physicians believed that the levels of insulin and C-peptide should be measured at the same time to assess islet function in patients with newly diagnosed and follow-up diabetes mellitus patients.Endocrinologists preferred to access insulin and C-peptide at the same time(P<0.05).56.0%of physicians chose bread meal test for T1DM patients and 54.7%for T2DM patients.Compared with non-specialists,endocrinologists preferred to commit bread meal test to T1DM patients(61.4%vs 41.0%,P<0.05).In addition,for the islet function assessment of new-onset diabetes patients,7.6%of physicians chose the six-point method(0,30,60,90,120,180 min),27.3%selected the five-point method I(0,30,60,120,180 min),8.5%selected the five-point method II(0,30,60,90,120 min),9.8%selected the four-point method I(0,30,60,120 min),10.3%selected the four-point method II(0,60,120,180 min),13.8%chose the three-point method(0,60,120 min)and 13.4%chose the two-point method(0,120 min).At the time of follow-up assessment,the above selection rates were 5.3%,20.4%,6.4%,6.6%,9.4%,15.8%and 24.1%,respectively.In terms of the frequency of assessment,39.2%of doctors assessed islet function once a year and 24.7%once every six months.Specialists preferred to assess islet function once a year,and physicians with senior titles chose to assess islet function more variably.Conclusion At present,there are still great differences in assessment methods of islet function in China.It is of great significance for the clinical diagnosis and treatment of diabetes to understand the differences in the selection of islet function assessment methods among doctors in different regions,specialties and job titles.
		                        		
		                        		
		                        		
		                        	
2.miR-135a-5p regulates autophagy of mouse embryonic palatal mesenchymal cells via targeting Kif3B
Wenxuan FENG ; Shubo LIAN ; Zhe WANG ; Jing CHEN ; Wei HE
Chinese Journal of Tissue Engineering Research 2024;28(19):3003-3011
		                        		
		                        			
		                        			BACKGROUND:Studies demonstrated that miR-135a-5p was highly expressed in mouse embryonic palatal mesenchymal cells with cleft palate induced by dexamethasone.The primary cilium and its mediated Shh signaling pathway were involved in the autophagy of mouse embryonic palatal mesenchymal cells.It is speculated that miR-135a-5p may regulate autophagy in mouse embryonic palatal mesenchymal cells through primary cilia and its mediated Shh signaling pathway. OBJECTIVE:To investigate the regulatory effect of miR-135a-5p on autophagy of mouse embryonic palatal mesenchymal cells. METHODS:In vitro,palatal mesenchymal cells from C57BL/6J mouse embryos were extracted and cultured.Cell transfections were set up as follows:(1)the cells were divided into control group,miR-135a-5p negative control group and miR-135a-5p mimic group;(2)NC+miR-NC group,KIF3B overexpression group,and miR-135a-5p+KIF3B group:qRT-PCR was performed to verify transfection efficiency of miR-135a-5p and KIF3B.A transmission electron microscope was used to observe the number of autophagosome/autophagolysosome in the cells of each group.The degree of fluorescence expression of autophagy marker LC3B was determined by the immunofluorescence technique.The protein expression of KIF3B,LC3 and P62 was determined by western blot assay.(3)The cells were divided into miR-135a-5p negative control group,and SAG treated group,and SAG+miR-135a-5p group.qRT-PCR was used to detect the mRNA expression levels of Gli3,a key transcription factor downstream of Shh signaling.The protein expressions of autophagy-related proteins LC3 and P62 were detected by western blot assay. RESULTS AND CONCLUSION:(1)After overexpression of miR-135a-5p,the number of autophagosome/autophagolysosome was significantly increased(P<0.01).The fluorescence density of LC3B increased significantly(P<0.01);the protein expression of KIF3B and P62 decreased(P<0.01),and the protein expression of LC3 increased.(2)After overexpression of KIF3B,the number of autophagosome/autophagolysosome was significantly decreased(P<0.01);the fluorescence density of LC3B was decreased(P<0.01);the protein expression of P62 was increased(P<0.01),and the protein expression of LC3 was decreased(P<0.01).Targeted expression of KIF3B was inhibited by miR-135a-5p(P<0.01);the number of autophagosome/autophagolysosome,the fluorescence intensity of LC3B as well as the protein expression of LC3 were reversed(P<0.01)and the protein expression of P62 was decreased(P<0.01).(3)SAG significantly increased the mRNA expression of Gli3(P<0.01),increased the protein expression of P62(P<0.01),and decreased the protein expression of LC3(P<0.01).When miR-135a-5p was added,Gli3 mRNA expression was significantly decreased(P<0.01);P62 protein expression was decreased(P<0.01),and LC3 protein expression was reversed(P<0.01).(4)These results indicate that miR-135a-5p targets the inhibition of KIF3B and promotes autophagy in mouse embryonic mesenchymal cells possibly by negatively regulating the Shh signaling pathway.
		                        		
		                        		
		                        		
		                        	
3.Immune reconstitution and influencing factors in HIV infected men who have sex with men with access to antiviral therapy in Guangxi Zhuang Autonomous Region from 2005 to 2021
Ni CHEN ; He JIANG ; Huanhuan CHEN ; Qiuying ZHU ; Xiuling WU ; Jianjun LI ; Nengxiu LIANG ; Qin MENG ; Xuanhua LIU ; Jinghua HUANG ; Wenxuan HOU ; Zhaoquan WANG ; Guanghua LAN
Chinese Journal of Epidemiology 2024;45(4):529-535
		                        		
		                        			
		                        			Objective:To analyze immune reconstitution and influencing factors in HIV infected men who have sex with men (MSM) with access to antiviral therapy (ART) in Guangxi Zhuang Autonomous Region (Guangxi) during 2005-2021.Methods:The data were collected from Chinese Disease Prevention and Control Information System. The study subjects were HIV infected MSM with access to the initial ART for ≥24 weeks in Guangxi from 2005 to 2021 and HIV RNA lower than the detection limit within 24 months. The proportion of infected MSM who had immune reconstitution after ART was calculated. Cox proportional hazard regression model was used to analyze the influencing factors of immune reconstitution. Software SPSS 24.0 was used for statistical analysis.Results:A total of 3 200 HIV infected MSM were enrolled, in whom 15.56 % (498/3 200) had no immune reconstitution, 14.78% (473/3 200) had moderate immune reconstitution, and the rate of complete immune reconstitution was 69.66% (2 229/3 200). The M ( Q1, Q3) of ART time for immune reconstitution was 12 (5, 27) months. Multivariate Cox proportional risk regression model analysis results showed that compared with those with initial ART at age ≥30 years, WHO clinical stage Ⅲ/Ⅳ illness, baseline BMI <18.50 kg/m 2 and baseline CD4 +T lymphocyte (CD4) counts <200 cells/μl, HIV infected MSM with initial ART at age <30 years, WHO clinical stageⅠ/Ⅱ illness, baseline BMI≥24.00 kg/m 2 and baseline CD4 counts ≥200 cells/μl were more likely to have complete immune reconstitution. Conclusions:In the HIV infected MSM in Guangxi, failures to achieve moderate and complete immune reconstitution were observed. Surveillance and ART regimen should be improved for key populations, such as those with older age and low baseline CD4 counts.
		                        		
		                        		
		                        		
		                        	
4.The safety and protective effect on resting dry mouth of optimized dose optimization in clinical target volume Ⅱa in patients with N 0-N 1 nasopharyngeal carcinoma
Wenxuan HUANG ; Shengfu HUANG ; Siyu ZHANG ; Lanfang ZHANG ; Lijun WANG ; Juying LIU ; Yizhi GE ; Xia HE
Chinese Journal of Radiation Oncology 2024;33(5):397-404
		                        		
		                        			
		                        			Objective:To analyze the safety of reduced clinical target volume (CTV) irradiation of suspicious positive lymph nodes in IIa region in patients with N 0-N 1 nasopharyngeal carcinoma (NPC) and the protective effect of submandibular gland and long-term resting dry mouth, and to explore the diagnostic value of multimodal imaging for suspicious cervical lymph nodes. Methods:Clinical data of T 0-4N 0-1M 0 stage NPC patients admitted to Jiangsu Cancer Hospital from July 2015 to April 2017 were retrospectively analyzed. Clinical, radiation therapy planning, multimodal imaging and other relevant data were collected. All patients were treated with an optimized regimen of IMRT with a prophylactic radiation dose of 50.4 Gy (named as CTV50) for IIa region. Imaging characteristics and treatment response of suspicious lymph nodes were monitored by MRI, MRI-DWI, PET-CT and repeated enhanced positioning CT, etc. The dosimetry of the submandibular gland between optimized and standard dose plans (CTV50 vs. CTV60) was compared by paired t-test. The long-term dry mouth degree of the patients was evaluated using advanced radiation injury from Radiation Therapy Oncology Group (RTOG), Jiangsu Cancer Hospital Multi-dimensional Dry Mouth Evaluation Scale and summated xerostomia inventory (SXI). The difference of dry mouth degree was analyzed by rank-sum test. Results:A total of 106 patients were included in this study, including 149 cervical lymph node negative sides, 73 sides of which had ≤3 recognizable lymph nodes, and 76 of which were>3 in Ⅱa region. Among patients with N 1 stage, 63 patients underwent contralateral single neck area optimization, and 43 patients (N 0 stage and N 1 stage patients with retropharyngeal lymph node metastasis) underwent double-neck area optimization. A total of 109 suspicious lymph nodes with a short diameter of >5 mm were found on the largest cross section, of which 105 had clear portal structure. The ratio of long to short diameter was ≥1.5 in 93 cases, and the maximum standardized uptake value (SUV max) in PET-CT was ≥2.5 in 76 cases. No lymph node recurrence was found in the CTV optimized area. There was no significant difference in the average dose of GTV in tumor target area after optimization ( P>0.05), and the D mean and V 39 Gy in submandibular gland were significantly lower than those in unoptimized plan (both P<0.01). There was no significant difference in long-term dry mouth and resting dry mouth between patients with unilateral and bilateral optimization of submandibular gland (both P>0.05). Conclusions:The optimal program of CTV50 reduction irradiation in Ⅱa area of N 0-N 1 NPC patients is safe and effective. The submandibular gland has obvious dosimetric advantages, and patients have a good subjective response to resting dry mouth. The multimodal imaging tools such as enhanced CT, MRI-DWI and PET-CT should be performed to deliver individual evaluation and treatment for suspicious lymph nodes.
		                        		
		                        		
		                        		
		                        	
5.Treatment strategy and prognostic analysis of nasopharyngeal necrosis after first radical radiotherapy for nasopharyngeal carcinoma
Dan ZONG ; Wenxuan HUANG ; Yesong GUO ; Jing WEN ; Lijun WANG ; Lanfang ZHANG ; Lirong WU ; Cheng CHEN ; Shengfu HUANG ; Xia HE ; Zhenzhang CHEN
Chinese Journal of Radiation Oncology 2024;33(9):797-803
		                        		
		                        			
		                        			Objective:To investigate the treatment strategy and prognostic factors of nasopharyngeal necrosis after the first radical radiotherapy for nasopharyngeal carcinoma.Methods:Clinical data of 1020 patients with nasopharyngeal carcinoma undergoing radical intensity-modulated radiotherapy in Jiangsu Cancer Hospital from January 2013 to January 2022 were retrospectively analyzed. Nasopharyngeal necrosis was confirmed by nasopharyngeal MRI, electronic nasopharyngoscopy and biopsy. Patients with nasopharyngeal necrosis were treated with electronic nasopharyngoscope irrigation debridement, combined with systemic anti-infection and nutritional support therapy. Kaplan-Meier method was used to calculate the survival, and Cox regression analysis was used to analyze the relationship between clinical factors and patients' survival.Results:Nasopharyngeal necrosis occurred in 20 cases of 1020 nasopharyngeal carcinoma patients after the first radical intensity-modulated radiotherapy, with an incidence rate of 1.96%. Odd smell and headache were common in nasopharyngeal necrosis patients. All patients had locally advanced nasopharyngeal carcinoma at initial treatment, including 2 (10%) cases of T 3 stage and 18 (90%) cases of T 4 stage. Nasopharyngeal necrosis occurred in the primary nasopharyngeal lesions. According to the stages of nasopharyngeal necrosis, there were 6 (30%) cases of stage I, 14 (70%) cases of stage II and no stage III. The occurrence time of nasopharyngeal necrosis was from 2 to 24 months after radiotherapy, and the median time was 5 months. All 16 cases of nasopharyngeal necrosis were cured clinically after debridement and irrigation under nasopharyngoscope, systemic anti-infection and symptomatic support treatment. Among them, 9 cases had no necrotic cavity and complete healing and 7 cases had residual necrotic cavity. Four patients died of massive nasopharyngeal hemorrhage or due to the inability to nasopharyngeal irrigation. The 5-year survival rates were 37.5% and 85.7% in patients with and without internal carotid artery involvement ( P=0.008), and 25.0% and 77.8% in patients with and without diabetes mellitus ( P=0.016). Univariate Cox regression analysis showed that necrotic lesions involving internal carotid artery ( HR=5.80, 95% CI=1.14-29.38, P=0.034) and diabetes mellitus ( HR=10.24, 95% CI=1.19-88.04, P=0.034) were the influencing factors of overall survival. Conclusions:Nasopharyngoscope irrigation debridement combined with anti-inflammation and nutritional support treatment are effective interventions for nasopharyngeal necrosis after the first radical intensity-modulated radiotherapy in patients with nasopharyngeal carcinoma. The necrosis involving the internal carotid artery and diabetes mellitus are important factors affecting the survival of patients. Vascular invasion caused by vascular rupture is the main cause of death.
		                        		
		                        		
		                        		
		                        	
6.The feasibility of individualized primary CTV for lateralized nasopharyngeal carcinoma
Siyu ZHANG ; Wenxuan HUANG ; Lijun WANG ; Juying LIU ; Lijun ZHAO ; Lirong WU ; Dejun WANG ; Wenjing XU ; Yesong GUO ; Pengwei YAN ; Lanfang ZHANG ; Zhenyu ZHAI ; Shengfu HUANG ; Xia HE
Chinese Journal of Radiation Oncology 2023;32(8):675-682
		                        		
		                        			
		                        			Objective:To investigate the feasibility of individualized primary clinical target volume (CTV) delineation in intensity-modulated radiotherapy for nasopharyngeal carcinoma (NPC).Methods:Clinical data of 87 consecutive patients newly diagnosed with lateralized NPC in Jiangsu Cancer Hospital between October 2016 and February 2018 were retrospectively analyzed. Lateralized NPC is defined as tumor invasion not exceeding the contralateral wall. According to the tumor spread, the primary CTV was optimized as follows: CTV2 only covered the medial part of the contralateral pterygopalatine fossa, whereas the contralateral foramen oval was not included; on the level of parapharyngeal space, the contralateral side of CTV only covered the posterior lateral lymph nodes, whereas the contralateral internal jugular vein was not regularly covered. Failure patterns and 5-year survival [local control rate (LCR), progression-free survival (PFS) and overall survival (OS)] were evaluated by Kaplan-Meier method. Paired t-test and rank-sum test were used to analyze the dose variation in the optimized region and adverse reactions. Results:The median follow-up time was 59.5 months. The 5-year LCR, PFS, and OS were 98.9%, 86.5% and 92.1%, respectively. There was no local recurrence in the optimized area of CTV. Dosimetric comparison results showed that the doses of parotid gland, temporal lobe, cochlea and middle ear on the contralateral side were reduced by 13.45%, 9.14%, 38.83%, and 29.36%, respectively. Four cases (4.6%) developed grade 3 hearing loss, all on the ipsilateral side. The optimized scheme significantly alleviated the hearing loss on the contralateral side compared to that on the ipsilateral side ( P<0.001). Other grade 3 late adverse reactions included cranial nerve injury, subcutaneous fibrosis in the neck and visual impairment, with 1 case each. Conclusion:Individualized primary CTV for lateralized NPC is feasible and safe, with obvious dosimetric advantages and reduced adverse reaction rate, which is worthy of clinical promotion.
		                        		
		                        		
		                        		
		                        	
7.Analysis of late-diagnosis and associated factors in newly reported HIV infections among men who have sex with men in Guangxi Zhuang Autonomous Region, 2005-2021
Wenxuan HOU ; He JIANG ; Qiuying ZHU ; Jinghua HUANG ; Jianjun LI ; Xiuling WU ; Xuanhua LIU ; Nengxiu LIANG ; Shuai TANG ; Qin MENG ; Bo LI ; Ni CHEN ; Guanghua LAN
Chinese Journal of Epidemiology 2023;44(10):1646-1652
		                        		
		                        			
		                        			Objective:To analyze the trend of late-diagnosis of HIV-infected men who have sex with men (MSM) before and after the AIDS Conquering Project in Guangxi Zhuang Autonomous Region (Guangxi) and its influencing factors, in order to find out the population groups that need priority intervention at the present stage.Methods:The HIV-infected MSM in Guangxi from 2005-2021 were selected from the National Integrated HIV/AIDS Control and Prevention Data System. The Joinpoint 4.9.1.0 software was used to test the time trend of late-diagnosis and non-late-diagnosis cases, and logistic regression was applied to analyze the factors influencing the proportion of late-diagnosis at each stage.Results:From 2005 to 2021, 5 764 HIV-infected MSM were reported in Guangxi from 2005 to 2021, with an overall late-diagnosis of 28.45% (1 640 cases). Under the 2015 baseline data as the boundary, the proportion of late-diagnosis cases showed a trend of sharp decline followed by stabilization from 2005 to 2015, average annual percent change= -6.90% ( P<0.001). The effect of factors such as resident population, occupation as a farmer or worker, and sample originating from medical consultation on late-diagnosis changed considerably before and after the implementation of the project, and the factors influencing late-diagnosis at this stage were age, resident population, occupation as a farmer, worker or student. The factors influencing late-diagnosis at this stage are age, resident population, and occupation as a farmer, worker and a student. Conclusions:The proportion of late diagnosis cases of HIV-infected MSM in Guangxi decreased significantly before and after the project. However, late-diagnosis should not be neglected and precise prevention and control should be carried out for the resident population, farmers, workers or students.
		                        		
		                        		
		                        		
		                        	
8.The strategy and feasibility of dose optimization in clinical target volume Ⅱb in patients with N 0-N 1 nasopharyngeal carcinoma
Wenxuan HUANG ; Dan ZONG ; Bin ZHANG ; Lijun WANG ; Lanfan ZHANG ; Chengxian MA ; Li YIN ; Shengfu HUANG ; Xia HE
Chinese Journal of Radiation Oncology 2022;31(9):778-784
		                        		
		                        			
		                        			Objective:To determine the safety of prophylactic irradiation dose CTV 60Gy optimized to CTV 50Gy for II b region in patients with stage N 0-N 1 nasopharyngeal carcinoma (NPC) and the dose advantage and clinical value for parotid gland protection, and to understand the diagnostic value of PET-CT and diffusion-weighted imaging (DWI) for suspicious positive lymph nodes in the neck (5 mm≤maximum short diameter<10 mm). Methods:Clinical data of 157 patients with primary non-metastatic NPC (N 0-N 1) admitted to our hospital from June 2015 to March 2017 were retrospectively analyzed. 104 patients underwent II b clinical target volume optimization guided by multimodal imaging system. Survival analysis was performed by Kaplan - Meier method. Univariate/multivariate regression analysis was performed to analyze the pattern of cervical lymph node recurrence. Paired t-test was used to compare the differences in target volume and parotid gland dose parameters before and after dose optimization. Results:Sixty patients underwent single-neck optimization in stage N 1, 25 patients received double-neck optimization (only those with retropharyngeal lymph node metastasis), and 19 patients underwent double-neck optimization in stage N 0. Three patients had cervical regional recurrence, all in-field. The 5-year overall survival rate was 93.3%. The lymph node recurrence-free survival rate, local recurrence-free survival rate, distant metastasis-free survival rate and disease-free survival rate were 97.1%, 91.3%, 88.5% and 80.8%, respectively. Cervical lymph node recurrence was associated with local recurrence in the nasopharynx, regardless of retropharyngeal lymph node status. Fourteen patients had suspicious positive cervical lymph nodes in II b region, with a mean maximum short diameter of 7.1 (5~9) mm on the largest cross-sectional plane, and 11 of them were positive on PET-CT, with a mean SUV max of 2.96 (2.5~3.3). There was no significant difference in GTV after optimization ( P>0.05). D mean, D max, D 50% and V 26Gy of parotid gland were significantly lower than those of conventional plan (all P<0.01). Conclusions:It is safe to optimize CTV 60Gy to CTV 50Gy in II b region in patients with N 0-N 1 NPC, and the exposure dose to normal tissues around the parotid gland and neck is significantly reduced. For small lymph nodes that do not meet the diagnostic criteria, it needs to be individualized in combination with multimodality imaging systems, such as PET-CT and DWI.
		                        		
		                        		
		                        		
		                        	
9.Clinical characteristics of patients with hemorrhagic fever with renal syndrome during pregnancy: a multicenter clinical study
Caini HE ; Hong DU ; Yinghua NIU ; Wenxuan ZHAO ; Ning GAO ; Shen LI ; Na HUANG ; Yunyu ZHAO ; Xiaofeng LI ; Yue ZHANG ; Mei LI ; Huan DENG ; Hailing LIU ; Yingren ZHAO ; Jianqi LIAN ; Fanpu JI
Chinese Journal of Infectious Diseases 2021;39(12):746-752
		                        		
		                        			
		                        			Objective:To analyze the clinical characteristics and prognosis of pregnant women with hemorrhagic fever with renal syndrome (HFRS).Methods:A total of 11 pregnant women with HFRS admitted to The Second Affiliated Hospital of Xi′an Jiaotong University (four cases), The Second Affiliated Hospital of Air Force Medical University (four cases), The First Affiliated Hospital of Xi′an Jiaotong University (one case) and Central Hospital of Xianyang City (two cases) between November 2009 and February 2019 were included as the study group, and 24 age-matched non-pregnant women with HFRS were selected as the control group. The age, complications, clinical classification and laboratory indexes of the two groups were analyzed retrospectively, and the clinical outcomes of pregnant women and their fetuses in the study group were followed up. The data between two groups were compared using Mann-Whitney U test or chi-square test. Results:Patients in the study and control groups were 29 (22, 33) and 32 (24, 37) years old, respectively. Seven of 11 patients in study group were severe and critical cases, which was significantly higher than that in the control group (16.7%(4/24), χ2=7.722, P=0.015). In the study group, 10 patients had hypervolemic syndrome, 10 patients had pulmonary edema and six patients had overlapping hypotension shock phase and oliguria phase, which were all higher than those in the control group ((2/24, 8.3%), (2/24, 8.3%) and (2/24, 8.3%), respectively; χ2=22.828, 22.828 and 9.135, respectively, all P<0.01). Compared with the control group, the pregnant patients in study group had a higher urea nitrogen maximum and serum creatinine maximum, and the differences were both statistically significant ( Z=-2.453 and -2.336, respectively, both P<0.05), while they had a lower serum albumin minimum, hemoglobin maximum and hemoglobin minimum, and the differences were all statistically significant ( Z=-3.742, -3.350 and -4.034, respectively, all P<0.01). All pregnant women with HFRS recovered. Nine pregnant women gave birth to nine healthy infants. All of them received breastfeeding and the feeding duration were more than six months. No abnormal growth and development were found during an average follow-up of three years. Conclusions:Pregnancy can aggravate the severity of HFRS, and pregnant women have higher risk of the multiple stages overlap and the complications such as hypervolemic syndrome and acute pulmonary edema. After recovery from HFRS, mother may carry to full-term pregnancy.
		                        		
		                        		
		                        		
		                        	
10.Determination of Cholesterol Content in Vegetable Oil for Rapid Screening Waste Oil
Wenxuan HE ; Run FANG ; Yanxia LI ; Shengxi ZHENG ; Jie LIN
Chinese Journal of Analytical Chemistry 2015;(3):394-398
		                        		
		                        			
		                        			The contents of cholesterol in a number of vegetable oils were determined by saponification-gas chromatography ( FID) . There was quite a large possibility that cholesterol peak was seriously interfered by saponification-gas chromatography ( FID) , so it was difficult to set a cholesterol content value to differentiate vegetable oil from waste oil. Solid phase extraction ( SPE) sample pretreatment was chosen and the process conditions were optimized. The optimal conditions were as follows:0. 25 g of oil samples, 20 mL of 0. 6%ethyl ether-hexane ( V/V) as eluent ( get rid of fatty acid glycerides) and 20 mL of 15% ethyl ether-hexane ( V/V) as eluent ( obtain cholesterol) . An obvious cholesterol-content-difference between vegetable oils and waste oils was found by SPE-GC. The detected cholesterol contents in 84 vegetable oil samples were all less than 50 μg/g and the contents of 11 waste oil samples among the 13 waste oils were greater than 50 μg/g. Therefore, cholesterol content in vegetable oil of more than 50 μg/g could be determined as suspected waste oil, not vice versa by SPE-GC. The correlation coefficient R2 was 0. 9999 in 0-760 mg/L concentration range, and the detection limit was 6. 0 μg/g. Relative standard deviations at two concentration levels of 17. 7 and 695 mg/L were 1. 6% and 1. 5% respectively. The recovery was 103%.
		                        		
		                        		
		                        		
		                        	
            
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