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To study the role of selenium compounds for the quality and nutritional value of meat, speciation of selenium compounds was performed in two muscles from each of seven animal species chicken, turkey, duck, ostrich, lamb, cattle and pig. Soluble selenium compounds were separated by size-exclusion chromatography SEC and detected by inductively coupled plasma-mass spectrometry ICP-MS. Four selenium peaks were found in the muscle extracts by SEC, with partition coefficients Kav of 0.02, 0.44, 0.74 and 0.86, respectively. The second and third peaks had a chromatographic mobility approximately corresponding to that of tetrameric glutathione peroxidase and selenoprotein W, respectively, and they contained 68–100 of the recovered selenium in different muscles. The distribution of selenium among the four peaks varied considerably in muscles from different species, the second peak accounting for 28–71 of the recovered selenium and the third peak for 17–72. These differences in selenium distribution among animal species are discussed in relation to meat quality and nutritional value.

To study the role of selenium compounds for the quality and nutritional value of meat, speciation of selenium compounds was performed in two muscles from each of seven animal species (chicken, turkey, duck, ostrich, lamb, cattle and pig). Soluble selenium compounds were separated by size-exclusion chromatography (SEC) and detected by inductively coupled plasma-mass spectrometry (ICP-MS). Four selenium peaks were found in the muscle extracts by SEC, with partition coefficients (K_av) of 0.02, 0.44, 0.74 and 0.86, respectively. The second and third peaks had a chromatographic mobility approximately corresponding to that of tetrameric glutathione peroxidase and selenoprotein W, respectively, and they contained 68–100% of the recovered selenium in different muscles. The distribution of selenium among the four peaks varied considerably in muscles from different species, the second peak accounting for 28–71% of the recovered selenium and the third peak for 17–72%. These differences in selenium distribution among animal species are discussed in relation to meat quality and nutritional value.

Abstract: Objectives: The aims of the study were threefold: to assess the skin uptake of the industrial catalyst dimethylethylamine (DMEA) (a) in vitro from water solutions by fresh guinea-pig and human skin specimens, (b) in gaseous form in vivo in human volunteers, and (c)␣to estimate the relevance of the uptake as an occupational hazard. Methods: Specimens from the in vitro and in vivo experiments were analysed by gas chromatography using a nitrogen-sensitive detector. Design: DMEA, diluted with water or isotonic saline solution was applied to fresh human or guinea-pig skin, mounted in Teflon flow-through cells with a perfusion fluid flow rate of 1.5 ml/h, samples being collected at 2-h intervals for 48 h. Three healthy male volunteers each had their right forearm exposed (in a Plexiglass chamber) for 4 h to DMEA at each of three different levels (250, 500 and 1000 mg/m3 air). Urine was collected up to 24 h after the start of each experiment. Results: DMEA penetrated both guinea-pig and human skin. The median steady-state flux and permeability coefficient (K p) values, were 0.009 mg/cm2 × h and 0.001 cm/h, respectively, for guinea-pig skin, and 0.017 mg/cm2 × h and 0.003 cm/h, respectively, for human skin. The median uptake in the three volunteers at the different DMEA exposure levels (250, 500 or 1000 mg/m3) was 44, 64 and 88 μg, respectively. The median K p for all experiments was 0.037 cm/h. Conclusion: Uptake of DMEA through the skin is of far less importance than simultaneous uptake via the airways. Thus, the amount of DMEA excreted in urine is a variable of limited use for the purposes of biological monitoring. Although a wide range of K p values was obtained in the in vitro experiments, both for guinea-pig and human skin, there was no marked difference in median K p values between the two types of skin. The K p values were lower than those obtained for human forearm skin in vivo. However, future studies of other tertiary aliphatic amines may show the in vitro␣method to yield values predictive of those obtained in in vivo studies.

Summary Dimethylethylamine (DMEA) is an aliphatic tertiary amine, which is used is a catalyst in the mould core manufacturing. During 8 h, four healthy volunteers were exposed to four different DMEA air concentrations (10, 20, 40 and 50 mg/m3; 20 mg/m3, two subjects only). DMEA was biotransformed into dimethylethyl-amine N-oxide (DMEAO). On average, DMEAO, accounted for 90% of the combined amount of DMEA and DMEAO excreted into the urine. The half-lives of DMEA and DMEAO in plasma were 1.3 and 3.0h, respectively. The urinary excretion of DMEA and DMEAO followed a two-phase pattern. The half-lives in the first phase were 1.5 h for DMEA and 2.5 h for DMEAO. In the second phase, which started about 9 h after the end of exposure, half-lives of 7 h for DMEA and 8 h for DMEAO were recorded. The combined concentration of DMEA and DMEAO, in both plasma and urine, showed an excellent correlation with the air concentration of DMEA. Thus, both urinary excretion and plasma concentration can be used for biological monitoring of exposure to DMEA. An 8-h exposure to 10 mg DMEA/m3 corresponds to a postexposure plasma concentration and 2-h postexposure urinary excretion of 4.9 µmol/1 and 75 mmol/mol creatinine, respectively.