OBJECTIVETo establish the method of detecting the concentrations of chlorpyrifos in air of workplace with high performance liquid chromatographic (HPLC).

METHODSAccording to standards of methods for determining the chemical substances in workplace air, chlorpyrifos in the air was collected by silicone tube, then dissolved by acetonitrile and determined by high performance liquid chromatography with UV-detector.

RESULTSThere was a linear relationship within the range of 0 ∼ 10.0 µg/ml, and regression equation was y = 5206.1x - 104.7, correlation coefficient was 0.9999, the detection limit was 0.006 µg/ml. The lowest detected concentration was 0.001 mg/m(3) (sampling volume 4.5 L). The average recoveries was 98.3% ∼ 102.5%. The within-run precision was 1.96% ∼ 4.39%, the between-run precision was 2.76% ∼ 5.87%. The desorption efficiencies were 99.0% ∼ 103.3% and the sampling efficiencies were 94%. The samples in silicone tube could be stored for 15 days at room temperature.

CONCLUSIONThe present method could meet with the requirements of Guide for establishing occupational health standards-Part 4 Determination methods of air chemicals in workplace and be feasible for determination of chlorpyrifos in workplace air.

Air Pollutants, Occupational ; analysis ; Chlorpyrifos ; analysis ; toxicity ; Chromatography, High Pressure Liquid ; methods ; Limit of Detection ; Reproducibility of Results ; Workplace

Objective According to results from the two-month consecutive surveillance program in Maanshan,six suspected cases of non-O1 non-O139 Vibrio (V.) cholerae infection,were found that called for identification of pathogens as well as molecular-epidemiological analysis to determine the aggregation of the epidemic situation.Methods Biochemical and serotype identification,hemolysis test,and drug sensitive test were used to detect the drug resistance spectrum.Real-time PCR and conventional PCR were used to detect the presence of V.cholerae specific genes,virulent genes and its related genes,including ompW,ctx,tcpA,toxR,hlyA,zot,ace,rstR and g ⅢCTX.Pulsed-field gel electrophoresis (PFGE) was used to analyze the molecular type of strains.Results All the six isolates of non-O 1 non-O 139 V.cholerae were identified by biochemical and serologic tests,and appeared to be β hemolytic.Twelve out of the 14 kinds of drugs showed 100％ sensitive.All isolates were positive of ompW gene by real-time PCR,but negative for ctx,tcpA,zot,ace,rstR and gⅢ CTK.Five of the six isolates were positive for toxR and hlyA,except for strain 1001434446.All strains had different PFGE types,but two strains had similar types.All strains had a low similarity compared to the toxigenic V.cholerae.Conclusion Six cases ofnon-O1 and non-O139 nontoxigenic V.cholerae infection appeared in the same period.Along with epide(m)iological information,we noticed that these cases had a sporadic nature,but frequently appeared in the same area.We got the impression that public health measurements should be strengthened,with special attention paid to those diarrhea outbreaks caused by non-O 1 /non-O 139 strains since V.cholerae had appeared in low incidence.

OBJECTIVE: To investigate the application of the optical magnetic bimodal molecular probe Gd-DO3A-ethylthiouret-fluorescein isothiocyanate (Gd -DO3A-EA-FITC) in brain tissue imaging and brain interstitial space (ISS). METHODS: In the study, 24 male SD rats were randomly divided into 3 groups, including magnetic probe group (n=6), optical probe group (n=6) and optical magnetic bimodal probe group (n=12), then the optical magnetic bimodal probe group was divided equally into magnetic probe subgroup (n=6) and optical probe subgroup (n=6). Referencing the brain stereotaxic atlas, the coronal globus pallidus as center level, the probes including gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA), fluorescein isothiocyanate (FITC) and Gd-DO3A-EA-FITC of 2 μL (10 mmol/L) were injected into the caudate nucleus respectively, magnetic resonance imaging (MRI) was performed in the magnetic probe group and magnetic probe subgroup to image the dynamic diffusion and distribution of the probes in the brain ISS, a self-developed brain ISS image processing system was used to measure the diffusion coefficient, clearance, volume fraction and half-time in these two groups. Laser scanning confocal microscope (LSCM) was performed in vitro in the optical probe group and optical probe subgroup for fluorescence imaging at the time points 2 hours after the injection of the probe, and the distribution in the oblique sagittal slice was compared with the result of the first two groups. RESULTS: For the magnetic probe group and magnetic probe subgroup, there were the same imaging results between the probes of Gd-DTPA and Gd-DO3A-EA-FITC. The diffusion parameters of Gd-DTPA and Gd-DO3A-EA-FITC were as follows: the average diffusion coefficients [(3.31±0.11)×10^-4 mm²/s vs. (3.37±0.15)×10^-4 mm²/s, t=0.942, P=0.360], the clearance [(3.04±0.37) mmol/L vs. (2.90±0.51) mmol/L, t=0.640, P=0.531], the volume fractions (17.18%±0.14% vs. 17.31%±0.15%, t=1.961, P=0.068), the half-time [(86.58±3.31) min vs. (84.61±2.38) min, t=1.412, P=0.177], the diffusion areas [(23.25±0.68) mm² vs. (22.71±1.00) mm², t=1.100, P=0.297]. The statistical analysis of each brain was made by t test, and the diffusion parameters were not statistically significant. Moreover, for the optical probe group and optical probe subgroup, the diffusion area of Gd-DO3A-EA-FITC [(22.61±1.16) mm²] was slightly larger than that of FITC [(22.10±1.29) mm²], the statistical analysis of each brain was made by t test, and the diffusion parameters were not statistically significant (t=0.713, P=0.492). CONCLUSION Gd-DO3A-EA-FITC shows the same imaging results as the traditional GD-DTPA, and it can be used in measuring brain ISS.
Animals ; Brain/diagnostic imaging* ; Caudate Nucleus ; Contrast Media ; Diffusion ; Fluorescein-5-isothiocyanate ; Fluorescence ; Gadolinium DTPA ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging ; Male ; Microscopy, Confocal ; Molecular Probes ; Rats ; Rats, Sprague-Dawley