Objective To establish a capillary electrophoresis method to separate ephedrine and psedudoephedrine. Methods RM-β-CD and HP-β-CD were set as additives. A capillary electrophoresis method was set up. The effects of types and concentrations of additives, the concentrations and pH values of buffered solution, running voltage and organic solvent on the separation of ephedrine and psedudoephedrine were investigated.Results Ephedrine and pseudoephedrine could be successfully separated by using either RM-β-CD or HP-β-CD as additives. When RM-β-CD was used as additive, the best separation conditions were as follows: separation voltage 10 kV, 25 mmol/L Tris-H3PO4 (pH 2.42), 20 mg/mL of RM-β-CD. Under the conditions, the resolution of ephedrine and pseudoephedrine was 1.56 and they were separated successfully within 13 min. When HP-β-CD was used as additive, the best separation conditions were as follows: separation voltage 10 kV, 25 mmol/L Tris-H3PO4 (pH 3.00), 50 mg/mL of HP-β-CD. Under the conditions, the resolution of ephedrine and pseudoephedrine was 2.73 and they were separated successfully within 15 min.ConclusionThis method is reliable, rapid and repeatable. It can be used as separation determination method for ephedrine and pseudoephedrine.

OBJECTIVETo understand the dietary consumption of residents in Xiamen and the content of phthalic acid esters (PAEs) in food, and to assess the plasticizer exposure risk of diet in Xiamen.

METHODSThe survey was conducted by stratified cluster random sampling method in Xiamen from September to October in 2010. According to the Xiamen administrative division, six neighborhood communities were selected as sampling units, then 25 families were randomly chosen from each sampling units.From the above 150 families, the permanent residents over the age of six were permitted to our study. The survey included 495 residents totally. These participants' information, such as basic personal information, physical activity levels, meal frequency and the average consumption of 33 kinds of food in 13 categories were collected using questionnaires. Thirteen categories included cereal and tubers, beans, vegetables, fungi and algae, fruits, dairy products, meat, seafood, eggs, snacks, beverages, cooking oil and spices. The height and weight of residents were measured and the average daily dietary intake was calculated. Thirty-three kinds of food in 13 categories were collected in supermarkets in Xiamen. According to the annual sales ranking, the top three-five brands of each kinds of food were selected and numbered, then two or three brands were chosen by random number table method from them; three completely individual packed samples in the same batch of each brand were detected; 243 samples were included in our study.100-500 g solid samples or 100-500 ml liquid samples were collected. The content of diethyl phthalate (DEP), dibutyl phthalate (DBP), di (2-ethylhexyl) phthalate (DEHP) in food were detected by liquid chromatography mass spectrometry, which expressed by median (minimum-maximum). The exposure dose, contribution rate and risk index of PAEs were calculated by point estimation method.

RESULTSAccording to the average daily dietary intake of residents in Xiamen, the top three ones in 13 categories of food were cereal and tubers (337.16 g/d, 18.21%), vegetables (309.12 g/d, 16.69%) and fruits (213.20 g/d, 11.51%). The content of DEP, DBP or DEHP among different categories of food was significantly different (χ² values were 58.05, 50.19 and 102.10, P < 0.01). Among 13 categories of food, seafood contained the most DEP (0.090 (0.000-0.324)mg/kg); cooking oil had the most DBP (0.700(0.000-2.980) mg/kg) and DEHP (5.115(0.000-24.160) mg/kg). DEP, DBP and DEHP exposure(0.19, 4.20, 18.10 µg × kg⁻¹ ×d ⁻¹)in dietary food in Xiamen were less than the reference dose(RfD) (800, 100, 20 µg × kg⁻¹ × d⁻¹) proposed by the United States Environmental Protection Agency (EPA), and the risk indexes were 0.02%, 4.20% and 90.50%, respectively. Among 13 categories of foods, seafood was the main source of DEP dietary exposure. The exposure dose and contribution rate of DEP in seafood were 0.18 µg × kg⁻¹ × d⁻¹ and 94.74%, respectively.Vegetables were the main source of DBP and DEHP dietary exposure. The exposure dose and contribution rate of DBP and DEHP were 1.48 µg × kg⁻¹ × d⁻¹, 35.24% and 6.07 µg × kg⁻¹ × d⁻¹, 33.54%, respectively.

CONCLUSIONThe food consumed by residents in Xiamen was overall in a safe state, but to some extent, there still exists DEHP exposure risk in foods.

China ; Dibutyl Phthalate ; Diet ; Diethylhexyl Phthalate ; Food Contamination ; Humans ; Phthalic Acids ; Plasticizers ; Risk Assessment ; Seafood ; United States ; Vegetables

BACKGROUND:Skeletal muscle insulin resistance is the key pathological link of type 2 diabetes.Static exercise can effectively improve skeletal muscle insulin resistance,but the mechanism remains unclear. OBJECTIVE:To explore the mechanism of static exercise on insulin resistance in the skeletal muscle of type 2 diabetic mice based on the phosphatidyl inositol 3-kinase(PI3K)/protein kinase B(AKT)/glucose transporter(GLUT4)signaling pathway. METHODS:After 1 week of adaptive feeding,7 out of 40 C57BL/6 mice were randomly selected as blank group and fed common diet,while the other mice were fed high-fat diet and taken to prepare type 2 diabetes models through the low-dose streptozotocin intraperitoneal injection.Twenty-four mice were successfully modeled and they were randomly divided into model group(n=8),metformin group(n=8)and static exercise group(n=8),which continued to be fed high-fat diet.The metformin group was given 200 mg/kg metformin dissolved in normal saline(2 ml/kg)by gavage,once a day,for 6 weeks.The static exercise group was given normal saline daily by gavage and carried out static exercise,30 minutes a day,6 days per week.The model group was given the same dose of normal saline daily by gavage without exercise intervention.After the intervention,the fasting blood glucose of each group was detected,the intraperitoneal glucose tolerance test was performed,and the area under the glycemic curve was calculated.Glycosylated hemoglobin,serum insulin,insulin resistance index were detected by ELISA.Total cholesterol,triglyceride,high-density lipoprotein,low-density lipoprotein were detected using biochemical methods.The mRNA expression levels of PI3K,AKT and GLUT4 in the gastrocnemius of mice were detected by real-time quantitative PCR.Morphological changes of the gastrocnemius were observed by hematoxylin-eosin staining,and the cross-sectional area of muscle fibers was calculated. RESULTS AND CONCLUSION:Compared with the blank group,fasting blood glucose,glycosylated hemoglobin,area under the glycemic curve,insulin resistance index,total cholesterol,triglyceride and low-density lipoprotein levels were significantly increased in the model group(P<0.01,P<0.05).Whereas,these indicators were significantly lower in the static exercise and metformin group than the model group(P<0.01,P<0.05).Compared with the blank group,serum insulin and high-density lipoprotein levels were significantly declined in the model group(P<0.01)and the mRNA expression of PI3K,AKT and GLUT4 in the gastrocnemius of mice were also significantly reduced(P<0.01).These indicators were significantly elevated in the metformin group and static exercise group compared with the blank group(P<0.01).Compared with the blank group,the muscle fibers in the model group were disordered,and the muscle cells atrophied and the muscle fiber gap widened.The cross-sectional area of muscle fibers was significantly decreased in the model group compared with the blank group(P<0.01).Compared with the model group,atrophy of the gastrocnemius fibers and muscle fiber space were improved in the static exercise group and the metformin group,and the cross-sectional area of muscle fiber was significantly increased in both groups(P<0.01).These findings indicate that static resistance training may promote glucose uptake and utilization by up-regulating the expression of PI3K,AKT and GLUT4 mRNA in skeletal muscle tissue,thereby improving the morphology and function of skeletal muscle tissue,alleviating insulin resistance and regulating glucose homeostasis.