Dalene M, Jakobsson K, Rannug A, Skarping G, Hagmar L
Department of Occupational and Environmental Medicine, Lund University Hospital, Sweden.
Int Arch Occup Environ Health. 1996;68(3):165-9. doi: 10.1007/BF00381626.
The object of this study was to investigate whether exposure of pipe-layers to thermal degradation products of diphenylmethane diisocyanate (MDI) could be assessed by analysing 4,4-methylenedianiline (MDA) in hydrolysed plasma and urine, and whether the genotype for N-acetylation affected these biomarker levels. Blood and urine samples were drawn from 30-pipe-layers who had been welding polyurethane (PUR) insulated pipes during the preceding 3 months. MDA in hydrolysed plasma and urine was determined with a gas chromatography-mass spectrometry technique, and genotype for N-acetylation was analysed with a polymerase chain reaction technique. MDA in plasma was detected in 18 of the 30 pipe-layers. Their plasma concentrations of MDA varied from 0.05 to 8.48 micrograms/l. There was a significant negative correlation between time since last welding of PUR-insulated pipes and P-MDA (rs = 0.50, P = 0.005). There was also a significant positive correlation between the estimated number of welded PUR-insulated pipes during the preceding 3 months and P-MDA (rs = 0.68, P = < 0.001). No significant association between genotype of N-acetylation and P-MDA was observed in a multiple regression analysis when adjustment was made for the estimated cumulative exposure to thermal degradation products of MDI. MDA in urine was detected in only four of the 30 pipe-layers. These four subjects had been welding PUR pipes on the same day as the sampling, or on the day before. The present results indicate the spot plasma samples analysed for MDA may give a rather good estimate of exposure to MDI during the preceding months. P-MDA, but not U-MDA, therefore seems to be a useful biomarker of long-term exposure to MDI. The individual N-acetylation capacity did not affect the plasma levels of MDA.
本研究的目的是调查是否可以通过分析水解血浆和尿液中的4,4-亚甲基二苯胺（MDA）来评估管道铺设工人对二苯基甲烷二异氰酸酯（MDI）热降解产物的暴露情况，以及N-乙酰化基因型是否会影响这些生物标志物水平。从30名在前3个月内一直在焊接聚氨酯（PUR）绝缘管道的管道铺设工人中采集血液和尿液样本。采用气相色谱-质谱技术测定水解血浆和尿液中的MDA，并采用聚合酶链反应技术分析N-乙酰化基因型。30名管道铺设工人中有18人血浆中检测到MDA。他们的血浆MDA浓度在0.05至8.48微克/升之间。自上次焊接PUR绝缘管道以来的时间与P-MDA之间存在显著负相关（rs = 0.50，P = 0.005）。在前3个月内焊接的PUR绝缘管道估计数量与P-MDA之间也存在显著正相关（rs = 0.68，P = < 0.001）。在对MDI热降解产物的估计累积暴露进行调整的多元回归分析中，未观察到N-乙酰化基因型与P-MDA之间存在显著关联。30名管道铺设工人中只有4人尿液中检测到MDA。这4名受试者在采样当天或前一天一直在焊接PUR管道。目前的结果表明，分析MDA的即时血浆样本可能对前几个月MDI的暴露情况给出相当好的估计。因此，P-MDA而非U-MDA似乎是长期暴露于MDI的有用生物标志物。个体的N-乙酰化能力并未影响血浆MDA水平。
