Previously, we reported that Kagoshima, Japan, is an endemic area of canine silica urolithiasis. Tap water in Kagoshima contains significantly greater silica concentrations than other areas of Japan. Ingestion of silica from tap water may lead to the formation of silica uroliths in dogs. We measured the concentration of silica in tap water from various areas of Japan. Concentrations were higher in the city of Takeda（Oita prefecture） and in some areas around the city of Chikusei（Ibaraki prefecture）. Fast atom bombardment mass spectrometry analysis of water from Kirishima（Kagoshima prefecture）revealed that the character of water was similar to that after silica sintering. Removal of silica from tap water may decrease the risk of silica urolithiasis in dogs. We demonstrated that silica could be successfully removed from tap water with a reverse osmosis membrane water filter but not with a typical domestic water filter. We also sent internet-based questionnaires to owners of dogs with silica uroliths to investigate other possible etiologies of silica urolithiasis. The results revealed that the specific pet food brand may be related to silica urolithiasis. However, the concentration of total silica in pet food does not appear to be related to the formation of uroliths.

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Although it was reported that a long term supplementation of dietary L-tyrosine, an amino acid that is a precursor of catecholamine, alleviated the chronic stress induced behaviors, limited information is available on the comparison between the effects of L- and D-tyrosine during acute stress. In the present study, the short term effects of oral administration of L- and D-tyrosine on behavioral alterations induced by acute stress were investigated along with the analysis of these two forms of amino acid concentrations in the mouse brain. Locomotor activity in the open field was not altered by either L- or D-tyrosine. Plasma L-tyrosine concentration was greatly but D-tyrosine was moderately increased after 35 min of the treatment. Interestingly, D-tyrosine concentrations were 1.8-2.5 folds higher compared with L-tryrosine in the several brain sites, namely prefrontal cortex, hippocampus, striatum, thalamus, hypothalamus, brain stem and cerebellum of control mice. In all the brain sites determined, L-tyrosine treatment increased the concentrations of L-tyrosine, but D-tyrosine treatment did not increase D-tyrosine levels. In conclusion, our results suggest that orally administered L- and D-tyrosine did not modify locomotor activity, but transportation of tyrosine into brain may be different between L- and D-tyrosine in mice.

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The aim of this study is to determine and compare the effects of obesity on plasma adiponectin levels and peripheral blood leukocyte (PBL) adiponectin receptor 1 and 2 (ADIPO-R1 and -R2) expression in the obese dogs. Biochemical examination of blood including plasma enzymes, hormones and cytokines were measured concurrently. Expression levels of ADIPO-R1 and -R2 mRNA were determined by quantitative RTPCR. As results, obese dogs demonstrated a significant increase in insulin, FFA, LDH levels and a significant reduction in circulating adiponectin level compared to the control dogs. In genetically analysis, relative ADIPO-R1 and ADIPO-R2 mRNA expression levels on PBL compared to control PBL were also significantly higher in the obese dogs. Adiponectin receptor (ADIPO-R1 and ADIPO-R2) mRNA expression levels in the obese dog PBL were generally up-regulated compared to those of the control animals. Recently there are various observations for adiponectin concentration and adiponectin receptors mRNA expression levels in obesity. Further studies in obese dogs are needed for adiponectin and adiponectin receptors in order to be useful indicators.

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