Secretory and membrane-bound zinc enzymes have multiple important physiological functions. Hence, the activation process of these enzymes is thought to require spatially and temporally well-organized steps of zinc transport, trafficking, transfer, and coordination. However, the molecular mechanisms involved in this activation remain largely unexplored when compared with those of other metal enzymes. Further investigation is essential to understanding how zinc metabolism is sophisticatedly controlled, thereby contributing to greater understanding of zinc-related biology in contexts from physiology to diseases. In this review, current knowledge on the crucial roles of the ZnT family of zinc transporters, which are localized to the early secretory pathway, is briefly reviewed from the perspective of these transporters' involvement in the activation process of secretory and membrane-bound zinc enzymes. The roles of those ZnT transporters in the maintenance of secretory pathway homeostasis are also reviewed, emphasizing the molecular aspects.

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Iodine is a chemical element with atomic number 53 and one of the most valuable natural resources among the halogen elements. One third of all iodine in the world is produced in Japan. Japan has been regarded as an iodine-sufficient or even excessive country because Japanese has been consuming traditionally large amounts of iodine largely through the intake of seaweed. However, there is no national data on iodine nutrition and its relation to diseases. In this review, a variety of aspects of iodine and also iodine status in Japan is discussed.

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Objectives: A synthetic biodegradable artificial dura mater (DM) can provide benefits such as helping to avoiding viral infections. The major component of this artificial DM is poly (lactic-glycolic acid-caprolactone) co-oligomer (PLGC). For synthesis of the DM, a catalyst containing dibutyltin (DBT) and tin (II) octylate (OT) is used. DBT and OT remain in the DM. To establish a model for the evaluation of the safety of the DM, after intracranial implantation of each 1-cm-diameter disk, the maximum size for rats, the neurotoxic effects of the DM and a PLGC containing 100 ppm DBT (DBT-PLGC) or 200 ppm OT (OT-PLGC) were evaluated.
Methods: A circular disk of cranial bone of 1 cm in diameter was cut from each rat's skull. The artificial DM, DBTPLGC, or OT-PLGC was implanted onto the surface of the brain of each rat (the DM, DBT-PLGC, and OT-PLGC groups). The control group underwent a sham operation. Four weeks after the implantation, prepulse inhibition (PPI) and open field tests were performed. The neurotransmitters in discrete brain regions were determined by highperformance liquid chromatography.
Results: There was severe damage to the brains of several rats. There were no significant differences among the groups in any indexes in the PPI or open field tests. The mean value of dopamine in the hypothalamus in the DM group was significantly higher compared to that in the other groups. The mean 5-HIAA/5-HT in the midbrain of the DM group was significantly higher than that in the control group.
Conclusion: Although the effects of DM after the implantation were slight under the current protocol, further studies are required because of the severe damage most likely induced by the implantation. As an experimental model, if the circular cranial bone disk cut out were 8 mm in diameter, it may provide better results with less damage to the brain.

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High serum copper/ zinc ratio (CZR) has been shown to be associated with cardiovascular disease (CVD) and all-cause mortality in elderly Western population. However, these associations have not been extensively studied in elderly population of Asian origin. Associations with traditional and non-traditional risk factors for CVD were examined in 202 community-living elderly Japanese women. After adjustment for age, associations with handgrip strength, log high-sensitivity C-reactive protein (hsCRP) and TNF-αremained significant and association with leukocyte count became significant. In multiple regression analysis, log hsCRP and handgrip strength emerged as independent determinants of CZR (R²=0.172). In conclusions, high CZR was independently associated with higher hsCRP and lower handgrip strength in freely- and community-living elderly Japanese women. Systemic low-grade inflammation and lower total body muscle strengthen may contribute to elevated serum copper/zinc ratio in the elderly, and may represent important confounders of the relationship between the ratio and mortality in this population

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This survey aimed to determine the levels of mercury in the scalp hair of residents of Hachinohe City in relation to their fish/seafood consumption to assess the risk of methylmercury exposure among the population. A total of 363 individuals (73 males and 290 females) residing in Hachinohe City (Aomori, Japan) provided scalp hair samples and completed a questionnaire. The geometric mean levels of mercury in the scalp hair were 2.52 and 1.91 μg/g in males and females, respectively, and 1.36 μg/g in females aged 15-49 years (n=80). The percentage of females of this generation with a hair mercury level above 2.2 μg/g (corresponding to the WHO's provisional tolerable weekly intake for methylmercury) was 21%, which was lower than the mean of 25% for residents of 10 regions across Japan. The Hachinohe residents consumed a mean of 108 g/day of fish/seafood (which was higher than the mean of 80.2 g/day for the overall Japanese population), consisting mainly of salmon, squid, mackerel, saury, and Atka mackerel. These results demonstrated that the hair mercury level of the residents of Hachinohe City was not so high as the higher consumption of fish/seafood compared with the national average, indicating that the risk of methylmercury exposure through increased fish/seafood consumption among Hachinohe City residents is not particularly high compared with the national level.

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