Determination of diphenylmethane diisocyanate in workplace air by HPLC with impregnated filter membrane / 中华劳动卫生职业病杂志

Objective@#To develop a method for determining diphenylmethane diisocyanate in workplace air by HPLC with impregnated filter membrane.@*Methods@#MDI in workplace air reacted with 1- (2-pyridyl) piperazine on impregnated filter membrane to form MDI-urea derivatives, after elution and filtration, it was detected by HPLC-UV.@*Results@#Limit of detection was 0.003 8 μg/ml and limit of quantification was 0.013 μg/ml. Good linearity was obtained in the range of 0.013~2.000 μg/ml (r=0.999 7) . The precision was 3.10%~8.03% (n=6) , while the recovery was 96.3%~101.9%. Asorption capacity of the membrane was 40.8 μg MDI, and could be stored for 14 days in the light-proof environment of 2~8 ℃.@*Conclusion@#The method optimized testing steps for MDI's standard curve, and provided good guidance for determination of MDI in workplace air with impregnated fiter membrane.

Determination of methylenedianiline in urine by high performance liquid chromatography-tandemmass spectrometry / 中华劳动卫生职业病杂志

Objective@#To develop a method for determination of metabolites of diphenylmethane diisocyanate (MDI) in urine, i.e. methylenedianiline (MDA) by high performance liquid chromatography-tandem mass (LC-MS-MS) . @*Methods@#Urine samples were prepared by hydrolyzation with sulfuric acid and extraction by acetonitrile, and then separated on a Shim-pack XR-ODS column, analyzed with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) . The external solvent standard calibration were tested. @*Results@#The linearity ranges were 0.05~20.00 μg/L, The related coefficients were 0.999 5. The limit of detection was 0.02 μg/L. The rats of recovery were 91.0%~103.4%. The relative standard deviations were between 2.7%~7.3%. @*Conclusion@#The method was sensitive, accurate and suitable for the MDA determination in urine of MDI exposed population.

Biomarkers Predicting Isocyanate-Induced Asthma

Three diisocyanates can cause occupational asthma (OA): toluene diisocyanate (TDI), 4,4 diphenylmethane diisocyanate (MDI), and 1,6-hexamethylene diisocyanate (HDI). We analyzed potential biomarkers of isocyanate-induced OA, based on investigated immunologic, genetic, neurogenic, and protein markers, because there is no serological testing method. The prevalence of serum IgG to cytokeratin (CK)18 and CK19 in TDI-OA was significantly higher than in controls, although the prevalence of these antibodies was too low for them to be used as biomarkers. Another candidate biomarker was serum IgG to tissue transglutaminase (tTG), because the prevalence of serum specific IgG to tTG was significantly higher in patients with TDI-OA than in controls. The human leukocyte antigen (HLA) DRB1*1501-DQB1*0602-DPB1*0501 haplotype may be used as a genetic marker for TDI-OA in Koreans via enhanced specific IgE sensitization in exposed subjects. The genetic polymorphisms of catenin alpha 3, alpha-T catenin (CTNNA3) were significantly associated with TDI-OA. Additionally, examining the neurokinin 2 receptor (NK2R) 7853G>A and 11424 G>A polymorphisms, the NK2R 7853GG genotype had higher serum vascular endothelial growth factor (VEGF) levels than the GA or AA genotypes among Korean workers exposed to TDI. To identify new serologic markers using a proteomic approach, differentially expressed proteins between subjects with MDI-OA and asymptomatic exposed controls in a Korean population showed that the optimal serum cutoff levels were 69.8 ng/mL for ferritin and 2.5 microg/mL for transferrin. When these two parameters were combined, the sensitivity was 71.4% and the specificity was 85.7%. The serum cytokine matrix metalloproteinase-9 (MMP-9) level is a useful biomarker for identifying cases of TDI-OA among exposed workers. Despite these possible biomarkers, more effort should be focused on developing early diagnostic biomarkers using a comprehensive approach based on the pathogenic mechanisms of isocyanate-induced OA.

A Study on Arrenotokous Toxic Action of Diphenylmethane Diisocyanate and Its Mechanism / 环境与健康杂志

Objective To evaluate the arrenotokous toxic action and the related mechanism of MDI in mature male KM mice. Methods The 8-month-old healthy KM mice were intraperitoneally injected with MDI maize oil solution at the dose of 0、62.5、125.0、250.0 mg/kg in normal control group and 3 experiment groups respectively for 14 days.The male mice were killed on day 15 for the measurement of the viscera coefficient of testis and epididymis, the sperm count in epididymis, the activities of enzymes of testis,and concentration of related hormone in testis and blood serum. Results There was no significant difference in body weight between the experiment and the control groups. The viscera coefficient of testis and epididymis in 250.0 mg/kg group decreased significantly compared with the control group(P