Rei Kono

Association between the Trail Making Test and physical performance in elderly Japanese.

Aim:  The Trail Making Test (TMT) is used in Western countries as an indicator of executive function, but there is little information regarding its use in Japan. Our previous initial study showed that the TMT was significantly associated with mobility‐related functions among elderly Japanese living in the community and in this study, we increased the number of participants to clarify that result.

Assessment of the best gait parameter in relation to bone status in community-dwelling young–old and old–old women in Japan

Even if physical exercise contributes to bone health of the elderly, intense activities have the potential to worsen the risk of osteoporosis. This fact and the inevitable decrease of mobility with age increase the likelihood that the mobility parameter that best benefits bone health differs with age. The aim of this study was to objectively assess the gait parameter that most strongly influences bone health of young-old and old-old women. Subjects comprised 200 community-dwelling elderly women (132 young-old, 68 old-old) registered at welfare centers for the aged. Bone status was examined in the right heel by quantitative ultrasound (QUS) and indicated as stiffness index (SI). Gait parameters including usual and maximum walking speed (UWS and MWS, respectively), daily walking steps (DWS), obstacle-negotiating gait, and stair-climbing were examined objectively. Other bone-related physical factors (body components, handgrip strength, and masticatory function) were measured and adjusted while performing assessment. After adjustment for covariates, multiple linear regression analysis showed that MWS had the strongest association with SI in young-old women and DWS had the strongest association with SI in old-old women. To prevent osteoporosis, brisk walking exercise and engaging in movement in everyday life, respectively, should be advocated for young-old women and old-old women in Japan.

Urinary yttrium excretion and effects of yttrium chloride on renal function in rats

Evaluation of yttrium exposure in biological samples has not been fully examined. To evaluate yttrium nephrotoxicity, yttrium chloride was orally administered to male Wistar rats and the urine volume (UV) and N-acetyl-β-d-glucosaminidase (NAG) and creatinine excretion (Crt) were measured in 24-h urine samples. The urinary yttrium concentration and excretion rate were determined by inductively coupled plasma-argon emission spectrometry (ICP-AES). Large significant decreases of UV (>30%) and Crt (>10%) were observed at yttrium doses of 58.3–116.7 mg per rat, but no significant NAG changes was observed. This response pattern shows that a high yttrium dosage alters glomerular function rather than the proximal convoluted tubules. A urinary yttrium excretion rate of 0.216% and good dose-dependent urinary excretion (r=0.77) were confirmed. These results suggest that urinary yttrium is a suitable indicator of occupational and environmental exposure to this element, an increasingly important health issue because recent technological advances present significant potential risks of exposure to rare earth elements. We propose that the ICP-AES analytical method and animal experimental model described in this study will be a valuable tool for future research on the toxicology of rare earth elements.

Obstacle-negotiating gait and related physical measurement indicators for the community-dwelling elderly in Japan

The aim of this study is to assess obstacle-negotiating gait (ONG) and explore its related physical factors. Subjects comprised 571 community-dwelling persons (195 men and 376 women) age>or=65 years and without cognitive impairment. ONG, timed up and go (TUG), and stair-climbing were measured and their relations were assessed. Walking ability (usual walking speed=UWS and daily walking steps=DWS), balance deficiency, and musculoskeletal function (handgrip strength and bone health) were examined objectively to explore ONG related physical factors. Logistic regression and general linear model analysis were performed with adjustment for age and body mass index (BMI). Time of ONG was 7.72s in men and 8.93s in women. Logistic regression analysis showed that the fast tertiles of ONG corresponding to the fast levels of TUG and stair-climbing had the highest odds ratio values. General linear model analysis showed that ONG was significantly associated with UWS and balance deficiency (no) in men, and with UWS, handgrip strength, DWS and balance deficiency (no) in women. Overall, ONG was considerably associated with falls screening tools and its determinants were also the main causes of falls. Training in ONG could be an attractive strategy for the prevention of falls among the elderly.

Comparison of the Biological Impacts of the Fluoride Compounds by Graphical Risk Visualization Map Technique

Various fluoride compounds are widely used in industry. The present risk assessment study was conducted using a series of inorganic binary fluorides of the type XFn, where Xn = Na+, K+, Li+, Mg2+, Ca2+, Sr2+, Ba2+, Al3+, Nd3+, La3+, Ce3+, Sm3+, Gd3+, Y3+, Yb2+, and Zn2+. The aqueous solutions of these salts were orally administrated to 16 experimental groups (one for each of the salts tested). The levels of fluoride, N-acetyl-β-d-glucosaminidase in cumulative 24-h urine samples and creatinine clearance were measured to assess possible acute renal damages. The levels of fluoride, alanine aminotransferase, and aspartate aminotransferase were also determined in serum samples to assess possible acute hepatic damages. The results reveal that sodium fluoride (NaF), potassium fluoride (KF), and zinc fluoride tetrahydrate (ZnF2.4H2O) can carry the fluoride ion into the bloodstream and that it is excreted via urine more readily than the other compounds tested. These fluorides were assigned the highest risk impact factor. Most of the rare earth fluorides are insoluble in water while those groups 2 and 13 of the periodic table are slightly soluble, so that they do not have a significant negative risk. These findings suggest that the biological impact of fluoride depends on the accompanying counter ion and its solubility. The risk map obtained in the present study shows that the graphical visualization map technique employed is a valuable new tool to assess the toxicological risk of chemical compounds.