Establishment of arsenic speciation analysis method and application in rice / 中华预防医学杂志

Objective@#A new ion exchange column technology was used to establish an efficient and sensitive method for the detection of inorganic arsenic.@*Methods@#Based on the new As Specia Fast Column, the pretreatment methods, liquid phase separation and mass spectrometry determination conditions of inorganic arsenic in rice were optimized. Finally, arsenic compounds were separated by As Specia Fast Column and detected by liquid chromatography inductively coupled plasma mass spectrometry. The external standard method was used for quantitative analysis. The detection limit, precision and accuracy of the method were determined by measuring the content of arsenic compounds in rice samples and rice standard samples. At the same time, three Guangdong rice samples were selected as the experimental samples of this study, and 1 g of each sample was weighed and measured in parallel three times. The method was compared with the method of liquid chromatography-atomic fluorescence spectrometry (LC-AFS) and liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) in the national standard.@*Results@#The inorganic arsenic in rice was extracted with 0.5% nitric acid solution at 65 ℃ for 15 h, and the pH was adjusted to alkaline. The mobile phase A (8 mmol/L HNO3, 50 mmol/L NH3·H2O) and mobile phase B (40 mmol/L HNO3, 80 mmol/L NH3·H2O) were used as the mobile phase gradient elution (93%) . Five arsenic compounds can reach baseline separation under the conditions of RF power of 1 500 W and atomization gas flow of 0.97 L/min. The detection limits ranged from 0.114 to 0.331 μg/L, and the inorganic arsenic content in rice samples ranged from 0.063 to 0.232 mg/kg. The results of determination of arsenic compounds in rice flour reference materials were all within the uncertainty range indicated by the standard. The recoveries were 86.7%~106.7%, and the precision was 1.9%-12.5%. Compared with national standards, the results of determination of arsenate in rice were relatively close (using this method, LC-AFS, LC-ICP-MS to detect the content of arsenate in rice samples 1 was 0.231, 0.226, 0.236 mg/kg, respectively). However, due to insufficient sensitivity, the national standard method is difficult to detect low levels of arsenic compounds (Arsenobetaine was not detected in rice sample 1). The method can detect the content of arsenobetaine in rice sample 1 was 0.023 mg/kg.@*Conclusion@#The established method can meet the requirements of inorganic arsenic determination in rice, and it is more rapid and accurate than the current national standard. It can better monitor and evaluate the content of i-As in rice, and provide accurate data for comprehensively grasping and evaluating the safety of rice consumption of residents.

Risk assessment of cadmium exposure in shellfish in Guangdong Province / 中国食品卫生杂志

Objective To investigate the content of cadmium in shellfish in Guangdong Province and make dietary exposure assessment of cadmium in shellfish.Methods The shellfish samples were collected from Pearl River Delta,Eastern and Western Guangdong Province using random sampling method.Point assessment method was used to evaluate the exposure of dietary cadmium intake from shellfish.The risk of dietary cadmium exposure from shellfish were evaluated.Results Three hundred and seven samples were included in the analysis.The median concentration of cadmium in shellfish was 0.630 mg/kg and the exceeding standard rate was 23.8％ (73/307).The exceeding standard rates in Eastern Guangdong,Western Guangdong and Pearl River Delta were 19.4％ (13/67),23.5％ (16/68),and 25.6％ (44/172),respectively.The corresponding median concentration of cadmium were 0.530,0.806 and 0.853 mg/kg,and the difference was not statistically significant (x2 =0.94,P ＞ 0.05).The average (P50) and high level (P97.5) daily intake of cadmium from shellfish by the total survey population was 0.957 μg/d,and 4.511 μg/d,respectively.The monthly intake of cadmium associated with shellfish calculated from average and P97.5 exposure doses accounted for 1.91％ and 9.02％ of PTMI,respectively.Conclusion The cadmium content of some shellfish in Guangdong Province exceeded the standard.However,the cadmium intake from shellfish by the survey population was not high.

The early toxic effect sensitive index of short-term-repeated exposure to cadmium chloride in male rats / 中国职业医学

OBJECTIVE: To observe the early adverse effect index caused by short-term-repeated exposure to cadmium chloride via oral perfusion in male rats. METHODS: Forty specific pathogen free healthy male SD rats were randomly divided into four groups: control group,low-,middle-and high-dose groups. The rats of low-,middle-and high-dose groups were treated with cadmium chloride 1. 11,3. 51 and 11. 06 mg/kg body weight,respectively,and the control group rats was treated with the same volume of ultra pure water,by gavage once a day for four weeks. During the experimental duration,the body weights of the rats were taken and activity status of the rats was observed. After the experiment,the rats were executed,and some indicators of main organ coefficients,blood routine,serum biochemical indexes,urine related effect indexes and bone mineral density were measured. RESULTS: During the experimental duration,rats of high-dose group showed the symptoms such as decreased activity,increase repose,move slowly and skin duller. Comparing with control group at the same time points,the body masses of the high-dose group of the 1-4 weeks were lower(P < 0. 05).After the experiment,comparing with control group,the weights of kidney and spleen of the high-dose group decreased significantly(P < 0. 05) and the liver coefficient increased significantly(P < 0. 05). The cadmium levels in blood,urine,liver,kidney and thighbone of the middle-and high-dose groups were higher than those of the control group(P < 0. 05).The red blood cell counts of the low-and middle-dose groups increased significantly(P < 0. 05). The level of hemoglobin of middle-and high-dose groups decreased(P < 0. 05),and the activity of alanine aminotransferase in high-dose groups increased significantly(P < 0. 05). Comparing with control group,the levels of urine α_1-microglobulin and urine β_2-microglobulin in urine of the middle-dose group were decreased(P < 0. 05) and the level of urine urea nitrogen increased(P < 0. 05),but there were no significantly changes of the above three indexes in the high-dose group(P >0. 05). There were no significant difference of the levels of N-acetyl-beta-D glucosaminidase in urine between control and treatment groups(P > 0. 05). Simultaneously,in high-dose group,the weight of thighbone,the bone calcium content and bone mineral density reduced significantly than those of the control group(P < 0. 05). CONCLUSION: Skeletal effects can be used as an early toxic effect sensitive index of short-term-repeated experiments exposure to cadmium chloride via oral perfusion in male rats.

Long-term effect of cadmium exposure on residents' renal dysfunction: An epidemiologic study / 中华预防医学杂志

<p><b>OBJECTIVE</b>To study long-term effect on renal function exposed to environmental cadmium.</p><p><b>METHODS</b>Stratified random sampling and cluster sampling method of epidemiological investigations were carried out in northern Guangdong province between April, 2011 and August, 2012. A total of 167 residents who lived in high cadmium exposure area for more than 15 years, aged above 40 were selected in exposed group. Moreover, A total of 145 residents who had similar living and economic conditions and lived in local for more than 15 years, aged above 40 were selected in control group. We used health questionnaires and medical examinations in order to acquire their health status. Home-harvested rice and vegetables were collected using quartering method for detection of cadmium level. Urine specimens of residents were collected for detection of cadmium level and creatinine as well as renal dysfunction biomarkers, namely, N-acetyl-beta-D-glucosamidase (NAG), β2-microglobulin (β2-MG), and retinol binding protein(RBP), respectively. The analysis of spearman rank correlation and multiple regression were used to investigate the relationships between age, urinary cadmium levels and renal injury biomarkers.</p><p><b>RESULTS</b>The cadmium levels in rice and vegetables of exposed group were 0.75 and 0.10 mg/kg, both were significantly higher than 0.07 and 0.01 mg/kg in the control group (Z values were -6.32 and -7.84, all P values < 0.001). The urinary cadmium level of exposed group was 8.29 µg/g · cr, which was higher than that of the control group 2.03 µg/g · cr with significant difference (Z value was -11.39, P < 0.001). After stratified the total population by age, the urinary cadmium level in 40-49 years, 50-59 years and ≥ 60 years subgroups were 7.22, 8.71, and 13.10 µg/g · cr, which both were significantly higher than 1.80, 2.04, and 2.05 µg/g · cr in the control group (Z values were -5.22, -7.41, and -7.14, all P values < 0.001). After stratified the total population by gender, the urinary cadmium level of male and female were 5.12 and 12.36 µg/g · cr, which both were significantly higher than 1.79 and 2.16 µg/g · cr in the control group (Z values were -7.68 and -9.03, all P values < 0.001). Comparing the differences of renal dysfunction biomarkers (NAG, β2-MG, RBP) between two groups. The level of urinary β2-MG and RBP of exposed group were 0.21 and 0.04 µg/g · cr, which were higher than 0.05 and 0.00 µg/g · cr of the control group with significant difference (Z value was -7.08 and -9.65, all P values < 0.001). Pearson correlation analysis showed that NAG, β2-MG and RBP were positively correlated with urinary cadmium and age, the correlation coefficients were 0.57, 0.49, 0.21 and 0.22, 0.26, 0.23 respectively (all P values < 0.001). After adjusting the effect of age, it was appeared that urinary cadmium levels contributed most to the alteration of NAG, β2-MG and RBP, the standardized regression coefficients were 0.57, 0.49 and 0.20 (all P values < 0.001), and suggested that the cadmium body burden was one of the most important factors for renal dysfunction.</p><p><b>CONCLUSION</b>Residents, who had cadmium contaminated rice and vegetables for a long time, would take the risk of increasing body burden of cadmium and urinary early biomarkers of renal tubular injury that referred to occurrence of renal dysfunction.</p>

Comparison of dual-source parallel radio frequence transmission liver MRI at 3.0 T with conventional MRI / 中华放射学杂志

Objective To investigate the role of dual-source parallel radio frequence (RF) and single-source excitation in liver imaging at 3.0 T MR.Methods This study was a retrospective analysis.One hundred and seven subjects underwent a 3.0 T TX MR scanning including axial spectrally selective attenuated inversion recovery (SPAIR) T2WI,axial DWI and coronal balanced-fast field echo( Balanced FFE).Each sequence was carried out with both single-source and dual-source RF excitation.Student＇s t test was used to compare the differences between single-source and dual-source RF excitation in the image uniformity,signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).Wilcoxon signed rank test was used to determine whether there was difference between conventional and parallel transmission in the score of image quality.Reader agreement was assessed using the Cohen＇s Kappa test.Results For the image uniformity,there was significant difference between single-source and dual-source excitation (418.40 ± 66.75 for single-source vs.416.26 ± 50.61 for dual-source,t =2.524,P ＜ 0.05 ).There also existed significant difference between single-source and dual-source excitation in SNR and CNR,respectively.The SNR and CNR of parallel transmission (22.03 + 12.16 and 18.33 ± 10.01,respectively) were both higher than those of single transmission (20.36 ± 11.21 and 15.22 ± 8.95,respectively) ( t =- 2.630,P ＜ 0.05 for SNR and t =- 4.238,P ＜ 0.05 for CNR).Image quality comparisons revealed significantly better results with dual-source than single-source RF excitation at SPAIR T2 WI ( 1.40 + 0.42 vs.1.81 ± 0.27 ),DWI ( 1.08 ± 0.40 vs.1.63 ± 0.36 ) and Balanced FFE sequence ( 0.95 ± 0.45 vs.1.65 ± 0.37,Z =- 5.894,- 5.801 and - 6.985,respectively,P ＜ 0.01 ).In the comparison of image quality,the agreement between the two readers was very good ( Kappa ＞ 0.8,P ＜ 0.05 ).Conclusion Dual-source parallel RF excitation MR imaging in liver enables reducing dielectric shading,improving homogeneity of the RF magnetic induction field,and increasing SNR and CNR at 3.0 T.

The preliminary application of the 3D ultrashort TE double echo pulse sequence in the bone and joint MR imaging / 中华放射学杂志

Objective To investigate the application of 3D ultrashort TE double echo pulse sequence in the bone and joint MR imaging. Methods Eight volunteers and a porcine fibula in vitro with intact muscle were involved in this study. Among the volunteers, one was suspected with meniscus tear, the others were asypmtomatic. MR imaging of 3D ultrashort TE double echo pulse sequence were performed on the tibial diaphysis, knee joint, ankle and wrist of each volunteer and the porcine fibula in vitro. Using the first echo images subtract with the second echo images, we observed the subtracted images from the primary double echo images and MPR images respectively. We then compared the difference of SNR. Four different echo times of the first echo (TE1) in the images were set as 0. 08 ms, 0. 16 ms, 0. 24 ms, 0. 35 ms. The quality of the subtracted images from the primary double echo images of the four different TE1 was compared.The MIP images from the primary double echo images with TE1 of 0. 08ms were performed to display the 3D structure of the ankle tendons. The data were analysed with One-Way ANOVA and Paired-Samples t test statistically. Results The 3D images of the tendons were displayed through MIP of the subtracted images from the primary double echo images. The cortical bones, periosteums, tendons and menisci of the 8 volunteers appeared as high signal intensity in UTE pulse sequence. The SNR of the subtracted images from MPR images (SNR, 3.76 ± 0. 88) was significantly higher than those from the primary double echo images(SNR,2. 82±0. 75) (t = - 4. 851, P < 0. 01). There were significant differences among the subtracted images from each of the four different TE1. The highest quality were obtained from the TE1 of 0.08ms. The CNR were as follows: CNR<,0.08ms>1.74±0. 54, CNR<,0.16ms> 1.35 + 0. 60, CNR0.24ms>1.20±0. 48,CNR<0.35ms> 0.89±0. 24 (F = 3. 681, P < 0. 05). The artifacts appeared markedly with prolonging of the TE1.Conclusion The MRI of ultrashort TE double pulse sequence may display the short T2 components that appeared as low signal with conventional clinical MR imaging, which made it pessible to quantify the tissues containing a majority of short T2 components.