Rat model for renal effects of 2-alkoxyalcohols and their acetates.

Male Wistar rats were given ethanediol (9.4 g/l), 2-ethoxyethylacetate (5.4 g/l), 2-butoxyethylacetate (2.9 g/l) and 1,2-propanediol (40 g/l) respectively in their drinking water for 2 weeks. Urine was collected during the last 24 h of the exposure. There was a marked increase in the oxalic acid excretion by the rats given ethanediol while rats given the alkoxyacetates excreted large amounts of ethoxyacetic and butoxyacetic acid, respectively. While not increased compared with controls, the excretion of oxalic acid by the latter group of rats was correlated to the excretion of the respective alkoxyacetic acids. The ammonia and glycosaminoglycan excretion was also smaller than that of controls. The urinary activity of succinate dehydrogenase was decreased in rats given the alkoxyacetates but not in animals exposed to ethanediol or propanediol. The data show that oxalic acid is actually a minor metabolite of the alkoxyacetates while the biochemical effects in kidney are associated more with the alkoxyacetic acid load. Alkoxyacetic acids seem to be inhibitors of renal succinate dehydrogenase, which may account for the decreased ammonia and glycosaminoglycan excretion.

Urinary biochemistry in occupational exposure to glycol ethers.

Glycol ethers and glycol ether acetates are dehydrogenated to alkoxyacetic acid congeners which may serve as biological indicators of exposure. The ethereal bond may also be cut in an oxidation reaction catalyzed by the mixed function oxidase. In case of ethylene glycol, the eventual endproduct is oxalic acid. Urinary oxalic acid and alkoxyacetic acid excretion together was found to relate to the decrease of the succinate dehydrogenase activity (SDH) as an indicator of renal mitochondrial effects. The excretion of ammonia by exposed workers was doubled as compared to controls. The excretion of chloride was found to be smaller in the exposed than in controls. The excretion of calcium and glycosaminoglycans (GAG) among exposed workers were similar compared to controls.

Identification and composition of types of granular urinary casts.

Granular urinary casts were analyzed by scanning electron microscopy and histochemistry. Three types were identified. They appear to have distinctly different origins and significance. Their clinical associations remain to be defined. One type can be misidentified by bright field microscopy. Bacterial casts also can be misidentified as granular casts unless the sediment is examined carefully.