Objective: The aim of this study is to investigate the association between breast cancer and serum selenium level as well as other risk factors for breast cancer.
Methods: A matched case-control study was conducted in a hospital in Malaysia from July 2000 to January 2001 and from May 2001 to June 2001. Sixty-two newly diagnosed breast cancer patients were selected as the cases. Each control, selected from the same hospital population was matched to each case according to age, ethnic group, and menopausal status.
Results: The mean selenium concentration among the cases was significantly lower than that among the control. There was a significant association (p<0.05) between breast cancer and low selenium serum level, nulliparity (OR=5.5, 95% CI=1.22 to 24.81), exposure to cigarette smoke (OR=2.2, 95% CI=1.04 to 4.65) and use of oral contraceptives (OR=3.0, 95% CI=1.09 to 8.25) as determined by the McNemar test. Multivariate analysis showed that nulliparity (OR=10.08, 95% CI=1.48 to 68.52) and use of oral contraceptives (OR=3.66, 95% CI=1.36 to 9.87) were associated with increased breast cancer risk. An increased selenium concentration contributes to a reduced risk of breast cancer (OR=0.89, 95% CI=0.84 to 0.94).
Conclusion: The results suggest that use of oral contraceptive pills, being nulliparous, and a low serum selenium level are associated with breast cancer.

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The purpose of this study is to develop a new system for measuring leg motions using a portable three-dimensional accelerometer. The measuring system is composed of acceleration sensors (MicroStone, MA3-10Ac), a data logger, a data reader, and a personal computer. The personal computer draws a graph of the acceleration of movements (i.e., accelerogram) from the output signals of the acceleration sensors. We then calculated the average acceleration to evaluate leg motions. We drew the accelerograms from 19 young subjects and 36 elderly subjects during the performance of physical fitness activities and walking. Different accelerograms were obtained from two subjects for different walking styles. The average accelerations at the lumbar, ankle and toe points were higher at all axes during movements from the physical fitness activities in the elderly subjects. The accelerations of leg motion at the knee point were, however, lower in the up and down axis in the elderly subjects than in the young subjects, although they were higher in the back and forth and the right and left axes. The new instrument has enabled us to evaluate leg motions by measuring three-dimensional acceleration during the performance of physical fitness activities and walking. The average accelerations of leg motions showed age-related changes. Thus, the average acceleration of leg motions may be used as a new index for evaluating leg motions at the dynamic state.

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Prevalence of age-dependent diseases such as asthma is confounded not only by aging effects but also by cohort and period effects. Age-period-cohort (APC) analysis is commonly performed to isolate the effects of these three factors from two-way tables of prevalence by age and birth cohort. However, APC analysis suffers from technical difficulties such as non-identifiability problems. We isolated the effects of these three factors in a step-by-step manner by analyzing Japan’s school health data collected from 1984 to 2004 focusing on asthma prevalence among school children aged 6–17 years consisting of 30 birth cohorts (entering classes). We verified the accuracy of our method showing high agreement of the observed age-, period- and cohort-specific data and the data predicted by our method. The aging effects were found to follow cubic equations whose multinomial coefficients were determined by an optimization technique. The obtained aging effect curves of age-specific asthma prevalence showed that boys reach the peak prevalence at 13 and girls at 14, declining markedly afterward. The cohort effects, defined as the arithmetic asthma prevalence means for ages 6–17 years, showed consistent upward trends for the 30 birth cohorts born in 1968–97 for both sexes. The period effects showed a consistent decline since 1984 but abruptly increased in 1999 and then declined again. We were not able to identify the exact cause of the increase in 1999, therefore, this should be examined in the future studies. Because the cohort effects show no sign of leveling off yet, asthma prevalence will likely increase in the foreseeable future.

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Objectives: An increase in incidence of the illegal use of tablets containing 3,4-methylenedioxymethamphetamine hydrochloride (MDMA) has recently become a widespread social problem. MDMA ingested orally reacts with nitrite in the stomach and is synthesized into N-nitroso-3,4-methylenedioxymethamphetamine (N-MDMA). The aim of this study is to investigate the genotoxic effects of MDMA and N-MDMA on the basis of the results of an in vitro micronucleus (MN) test and an in vitro chromosomal aberration (CA) test using a Chinese hamster lung fibroblast cell line (CHL/IU).
Methods: Tablets containing MDMA obtained from the Regional Bureau of the Ministry of Health, Labor and Welfare were purified, and N-MDMA was synthesized from MDMA in our laboratory. To evaluate the effects of MDMA and N-MDMA, the MN test established by our laboratory and the CA test in accordance with the guidelines for toxicity studies of drugs recommended by the Ministry of Health, Labor and Welfare were performed.
Results: In the MN test, no increased frequency of MNs was not found for MDMA. On the other hand, an apparently increased frequency of MNs was observed for N-MDMA. In the CA test, no CA was found for MDMA, but CA was observed for N-MDMA apparently.
Conclusion: N-MDMA genotoxicity was observed in the MN and CA tests. However, no MDMA genotoxicity was observed.

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Objectives: Particulate air pollution is a serious problem all over the world, and the development of a method to evaluate the health effects of ambient particles is necessary. In this study, cells cultured in vitro were exposed to particles sampled at the side of a main road, and their protein expression levels were examined.
Methods: Ambient particles were collected at the side of a main road using a high-volume air sampler. Some of the collected particles (crude particles) were treated with an organic solvent to remove chemical components, and the resulting residues were used as residual particles. Cells from the mouse alveolar epithelial cell line LA-4 were inoculated into tissue-culture dishes at 1.4×10⁴/cm², exposed to each type of particle or artificial carbon particles (Printex 90) that were dispersed using an ultrasonic homogenizer by mixing in the medium twice at 24 and 48 hours, and incubated for up to 72 hours after the start of inoculation. After exposure, the number of cells and intracellular dehydrogenase activity were measured. Proteins extracted from the cells were subjected to two-dimensional gel electrophoresis with isoelectric focusing at pHs 4–7 using a 10% acrylamide gel, and their expression levels were analyzed after fluorescent staining.
Results: The intracellular dehydrogenase activity of the cells significantly decreased as a result of exposure to the residual (0.70-fold) and crude (0.84-fold) particles compared with that of the control, but it showed no change as a result of exposure to Printex 90. The protein expression levels in the cells exposed to the particles increased or decreased similarly, but different expression levels were also observed. There were differences in the effects observed between the cells exposed to the artificial carbon particles and those exposed to particles collected from ambient air.
Conclusion: This study indicates that protein expression levels in cells change in response to exposure to particles collected from ambient air. To evaluate the effects of particles on health, it is considered necessary to use particles collected from ambient air.

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