No abstract

In the present study, ICP-MS with a new hybrid simultaneous preconcentration combining solid phase extraction using chelating resin and iron hydroxide coprecipitation in one batch at a single pH adjustment (pH 6.0) were developed for multielement determination of trace metal ions in seawater. In multielement determination, the present method makes it possible to determine Cr(III), As(V), Se (IV), and other 14 trace metal elements (Ti, V, Co, Ni, Cu, Zn, Zr, Ge, Cd, Sb, Sn, W, Pb, and U) in seawater. Moreover, for speciation analyses of Cr, As, and Se, the pH dependence on recovery for the different chemical forms of Cr, As, and Se was investigated. In speciation analyses, Cr, As, and Se were determined as the total of Cr (III) and a part of Cr (VI), total of As (III) and As (V), and Se(IV), respectively. Determination of total of Se and Cr(VI) remains as future task to improve. Nevertheless, the present method would have possibility to develop as the analytical method to determine comprehensively most metal elements in all standard and guideline values in quality standard in environmental water in Japan, that is, most toxic metal elements in environmental water.

This study reported acrylamide, a carcinogenic substance produced by the Maillard reaction, in dog food, as a part of understand the mechanism of canine carcinogenesis. These results indicated that the average concentrations of acrylamide in dry, retort, and canned dog food were 39.6, 11.0, and 10.7 ng/g, respectively. Among the three, dry dog food exhibited significantly higher concentration. The daily intake of acrylamide by dogs was calculated to be 590 ng/kg/day, which is approximately four times higher than that of humans.

Mast cells are a significant source of cytokines and chemokines that play a role in pathological processes. Gangliosides, which are complex lipids with a sugar chain, are present in all eukaryotic cell membranes and comprise lipid rafts. Ganglioside GM3, the first ganglioside in the synthetic pathway, is a common precursor of the specifying derivatives and is well known for its various functions in biosystems. Mast cells contain high levels of gangliosides; however, the involvement of GM3 in mast cell sensitivity is unclear. Therefore, in this study, we elucidated the role of ganglioside GM3 in mast cells and skin inflammation. GM3 synthase (GM3S)‐deficient mast cells showed cytosolic granule topological changes and hyperactivation upon IgE‐DNP stimulation without affecting proliferation and differentiation. Additionally, inflammatory cytokine levels increased in GM3S‐deficient bone marrow–derived mast cells (BMMC). Furthermore, GM3S‐KO mice and GM3S‐KO BMMC transplantation showed increased skin allergic reactions. Besides mast cell hypersensitivity caused by GM3S deficiency, membrane integrity decreased and GM3 supplementation rescued this loss of membrane integrity. Additionally, GM3S deficiency increased the phosphorylation of p38 mitogen‐activated protein kinase. These results suggest that GM3 increases membrane integrity, leading to the suppression of the p38 signalling pathway in BMMC and contributing to skin allergic reaction.

Summar yAs part of research on the method of collecting soil samples for mutagenicity measurement, a map of the former Sagamihara City was divided into a square mesh by drawing lines along every latitudinal minute and longitudinal minute. 40 surface soil samples were collected at the intersection points on the map, and the mutagenicity of the samples was examined by the Ames preincubation method using Salmonella typhimurium TA98 and TA100 strains. It was found that the average mutagenicity was 47 rev/g of soil when TA98 was used without S9mix, 87 rev/g of soil when TA98 was used with S9mix, 11 rev/g of soil when TA100 was used without S9mix, and 152 rev/g of soil when TA100 was used with S9mix, all of which were lower than the values reported in past documents, and were approximately the same as values obtained in the countryside. To provide an overview, the geographical distribution of specific mutagenic activity was examined. As a result, mutagenic substances easily detectable with TA98 strain (inducing frame shift type mutations) were found mostly in the center of the former Sagamihara City, whereas mutagenic substances easily detectable with TA100 strain (inducing base pair substitution type mutations) were found to have spread over the whole of Sagamihara City. In order to look for hot spots, and in order to understand the distribution of mutagenicity, a sampling plan using non-arbitrary selection of sites as in the present study was effective.