For the purpose of obtaining standard levels of toxic metals in the Japanese, hair samples are collected from 5,846 healthy Japanese (2,201 men and 3,645 women; average age 39.9 ± 16.3, means±SD) and the contents of mercury, lead, arsenic, cadmium, beryllium and aluminum in hair were measured with an inductively coupled plasma mass spectrometer (ICP-MS). Among the adults aged 16 or older, men’s average content of mercury was high at 5.38 ± 4.37 ppm and women’ s was 3.37 ± 2.45 ppm. Thus men showed higher contents. The content of lead was 1.09 ± 4.87ppm with men and 1.56 ± 10.58 ppm with women, who showed higher contents. Arsenic content was measured to be 69 ± 86 with men and 38 ± 92 ppb with women. Men had higher arsenic contents. Cadmium content was 28 ± 106 ppb with men and 28 ± 55 ppb with women. Beryllium content was 1.6 ± 2.0 ppb with men and 2.0 ± 4.1 ppb with women. And aluminum content was 5.01 ± 5.82 ppm with men and 6.02 ± 6.61 ppm with women. Thus, a significant difference was not noted. Children aged 15 and younger had higher contents of cadmium and aluminum than adults. Hair mineral analysis is deemed useful in diagnosing acute or chronic poisoning by these toxic metals or determining exposure to them.

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The main cause of glycative stress is an excess of aldehydes, and it is particularly important to suppress postprandial hyperglycemia, which is involved in the production of aldehydes. This is because many types of aldehydes are produced in a chain reaction following postprandial hyperglycemia. In order to understand the conditions for the occurrence of postprandial hyperglycemia, we have performed many blood glucose tests. Initially, we measured blood glucose via fingertip punctures, but in 2019, we introduced a method of monitoring blood glucose levels for two consecutive weeks using the FreeStyle Libre (Abbott). This has dramatically reduced the burden and pain of subjects by eliminating frequent pain and bleeding in the fingertips. In recent years, the model has been changed from Libre Pro to Libre 2, and the measurement interval has been shortened from the conventional 15 minutes to 1 minute. In this study, we compared the difference in the "postprandial blood glucose change curve" between the new and old models. As a result, it was shown that changes in blood glucose levels can be detected with high sensitivity even when sugar-containing sweetened beverages are consumed during meals. In our laboratory, we plan to conduct blood glucose level tests using the new model (Libre 2) in the future.

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Diabetes mellitus is closely related to diseases such as macrovascular disorders. The main causes of macrovascular disorders are the products of non-enzymatic glycation reactions, i.e., advanced glycation end products (AGEs). Zinc (Zn) complexes are known to exhibit hypoglycemic activity, with some Zn complexes suppressing AGE formation. In this study, we show that the relationship between the suppressive activities against AGE formation in Zn complexes and hypoglycemic activity depends on the coordination mode. We compare the Zn(O₄)-type zinc complexes [Zn(mal)₂] and [Zn(opd)₂] and the Zn(S₂O₂)-type Zn complexes [Zn(tmal)₂] and [Zn(opt)₂]. The formation of fluorescent AGEs is suppressed by all Zn complexes, while pentosidine formation is suppressed by [Zn(mal)₂] (IC₅₀ = 308 ± 88 μM) and [Zn(opd)₂] (IC50 = 47 ± 7 μM) but not by [Zn(tmal)₂] or [Zn(opt)₂]. The Zn(S₂O₂)-type Zn complexes are therefore predicted to exhibit stronger antiglycation effects than Zn(O₄)-type Zn complexes: however, Zn(S₂O₂)-type Zn complexes do not always exhibit strongly suppress antiglycation or pentosidine formation. We found that Zn(O₄)-type Zn complexes exhibit a stronger antiglycation effect than Zn(S₂O₂)-type Zn complexes.

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