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Objective@#To obtain the dietary exposure of lead in primary, middle and high school students, and to provide basic foundation for food safety risk assessment and management for children and adolecsents.@*Methods@#Weighing method, 3-days hour dietary survey, combining with the food frequency questionnaire, was applied to obtain basic dietary data in 616 primary, middle and high school students selected through multi-stage randdom sampling method from Pudong new area of shanghai. Data on lead concentrations were derived from the food safety risk monitoring system, which included 1 145 samples.@*Results@#Lead was detected in 568 of 1 145 samples (49.61%) from 10 categories of foods. The exceeding standard rate was 3.58% (41 samples exceeded). The average content of lead was (0.12±0.25) mg/kg, fungi and algae, beans and the aquatic products were found to be the primary food sources of lead exposure. The average dietary lead exposure in primary, middle and high school students was 9.94 μg/kg per week, accounted for 39.76% of PTWI. The lead exposure level at the 97.5th percentile which accounted for 118.24% of PTWI was 29.56 μg/kg. Vegetables, beans and cereal foods were the mainly source of dietary lead exposure, with average dietary lead exposure 2.57, 2.44 and 1.43 μg/kg peer week, accounted for 10.26%, 9.76% and 5.74% of PTWI, respectively.@*Conclusion@#Lead is present in some foods available in local markets in Pudong New Area, Shanghai. Low level of dietary exposure to lead is found in primary, middle and high school students, however, it depends on dietary pattern. Continued efforts are needed to reduce the dietary exposure of lead in school students.
ABSTRACT
A novel electrochemical sensor for the determination of podophyllotoxin (PPT) was prepared by modifying a PPT-imprinted membrane, which was synthesized by in situ polymerization with PPT as template, methacrylic acid ( MAA) as functional monomer and ethylene glycol dimethacrylate ( EGDMA) as cross linking agent at the molar ratio of PPT/ MAA/ EGDMA as 1 : 2 : 100, on glassy carbon electrode ( GCE) followed by eluting PPT from the modified GCE with methanol/ acetic acid (1: 1, V/ V). The properties of the electrochemical sensor modified with PPT-imprinted membrane were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS). Under the optimum conditions, it was found that the response of peak currents was linear to the concentration of PPT in range of 1. 0 - 120 μmol/ L with the detection limit of 0. 47 μmol/ L. The sensor not only showed high selectivity, but also exhibited good stability and reproducibility. The sensor was satisfactorily applied to the determination of PPT in podophyllum hexandrum and human serum samples with the relative standard deviation (RSD) below 3. 9% and recovery ranging from 95. 0% to 103. 3% .
ABSTRACT
Objective To evaluate the effects of dezocine on diabetic neuropathic pain (DNP ) and expression of NMDA receptor subunit 2B (NR2B) in the spinal dorsal horns of rats .Methods Forty-eight male Sprague-Dawley rats , aged 4 weeks , weighing 150-170 g , with DNP induced by intraperitoneal injection of streptozocin (STZ) 50 mg/kg (successful induction of diabetes was defined as blood glucose >16.7 mmol/L) , were randomly divided into 2 groups ( n=24 each) using a random number table:DNP group and dezocine group (group D) .Twenty-four normal rats were chosen and served as normal control group (group C) .In group D , dezocine 2.52 mg/kg was injected intramuscularly once a day for 7 consecutive days starting from 2nd week after STZ injection ,while the rats in DNP and C groups received the equal volume of normal saline .Paw withdrawl threshold (PWT) to mechanical stimulation was measured before dezocine injection (T0 ) ,and on 1st ,3rd ,5th and 7th days after dezocine injection (T1-4 ) and on 7th day after the end of dezocine injection (T5 ) .Twelve rats in each group were sacrificed after measurement of PWT at T4 ,and T5 .The lumbar segments of the spinal cord were removed for determination of NR2B protein expression (by immuno-histochemistry and Western blot ) and NR2B mRNA expression (by RT-PCR ) in the spinal dorsal horns .Results Compared with group C ,the PWT at T0-5 in group DNP and at T0 and T5 in group D was significantly decreased , and the expression of NR2B protein and mRNA at T4 ,5 in DNP group and at T5 in D group was up-regulated ( P0.05) . The PWT was significantly lower at T0 and T5 ,and the expression of NR2B protein and mRNA was higher at T5 than at T4 in group D ( P<0.05 ) .Conclusion Dezocine can effectively relieve DNP in rats and inhibition of NR2B expression in the spinal dorsal horns is involved in the mechanism .