Chiba Prefectural Institute of Public Health

Chūō-ku, Japan

Chiba Prefectural Institute of Public Health

Chūō-ku, Japan
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Hirai S.,Chiba Prefectural Institute of Public Health | Hirai S.,Chiba University | Yokoyama E.,Chiba Prefectural Institute of Public Health | Yamamoto T.,Chiba University
Infection, Genetics and Evolution | Year: 2013

The distribution of insertion sequence (IS) 629 was investigated among enterohemorrhagic Escherichia coli O157:H7/H-(O157) strains in different clades. Minimum spanning tree analysis showed that most strains in each clade clustered in a separate branch, indicating biased distribution of the IS. 629 insertion in different clades. The standardized index of association of the IS. 629 distribution data showed linkage disequilibrium in the strains in every clade, indicating that IS. 629 distribution data could be used for population genetic analysis. For this population genetic analysis, the ΦPT value, an analogue of FST, was calculated and indicated that clade 7 strains could be split into two clades based on their lineages. The degree of pairwise linkage disequilibrium was quite different among these two groups. The clade 7 split was in agreement with the model of O157 paraphyletic evolution and a new designation of the lineage II clades was proposed. The prevalence of strains with an IS. 629 insertion in certain loci was significantly different in different clades. Some of these significant differences were in loci in strains in branches of clades that were close in the O157 phylogenetic model, suggesting that IS. 629 insertion/deletion was not directly related to the divergence of O157 clades. © 2013 Elsevier B.V.


Matsuda S.,Chiba University | Saika S.,Chiba Prefectural Institute of Public Health | Amano K.,Chiba Prefectural Institute of Public Health | Shimizu E.,Chiba University | Sajiki J.,Chiba Prefectural Institute of Public Health
Chemosphere | Year: 2010

To examine whether exposure to bisphenol A (BPA) at low levels affect brain function, monoamine concentrations in hippocampus, striatum and brain stem, were investigated in neonatal male rats injected intracranially with BPA at 0-10 μg kg-1. Significant increases of serotonin (5-HT) in hippocampus, 5-HIAA and 5-HIAA/5-HT in brain stem, dopamine (DA) and DOPAC in striatum were observed at 28 d after the injection on postnatal day 2. At 7 d after the injection, increases in 5-HT and norepinephrine (NE) and decreases in DOPAC and 5-HIAA were observed in hippocampus. To investigate the degradation of BPA in brain, we also measured BPA concentrations of whole neonatal rat brain. Free BPA disappeared from brain tissues within 5 h, even when the highest dose (1000 μg kg-1) was injected. The present results suggest that BPA exposure at lower doses than environmentally relevant levels may have a great impact on monoamine levels in neonatal brain over 28 d after its disappearance. © 2009 Elsevier Ltd. All rights reserved.


Tanabe N.,Niigata University | Iso H.,Osaka University | Okada K.,Ehime University | Nakamura Y.,Kyoto Women's University | And 4 more authors.
Circulation Journal | Year: 2010

Background: Few Japanese studies have compared serum non-high-density lipoprotein (non-HDL) cholesterol with serum total cholesterol as factors for predicting risk of cardiovascular events. Currently, few tools accurately estimate the probability of developing cardiovascular events for the Japanese general population. Methods and Results: A total of 22,430 Japanese men and women (aged 40-89 years) without a history of cardiovascular events from 10 community-based cohorts were followed. In an average 7.6-year follow up, 104 individuals experienced acute myocardial infarction (AMI) and 339 experienced stroke. Compared to serum total cholesterol, serum non-HDL cholesterol was more strongly associated with risk of AMI in a dose-response manner (multivariable adjusted incidence rate ratio per 1 SD increment [95% confidence interval]=1.49 [1.24-1.79] and 1.62 [1.35-1.95], respectively). Scoring systems were constructed based on multivariable Poisson regression models for predicting a 5-year probability of developing AMI; the non-HDL cholesterol model was found to have a better predictive ability (area under the receiver operating curve [AUC] =0.825) than the total cholesterol model (AUC= 0.815). Neither total nor non-HDL serum cholesterol levels were associated with any stroke subtype. Conclusions: The risk of AMI can be more reliably predicted by serum non-HDL cholesterol than serum total cholesterol. The scoring systems are useful tools to predict risk of AMI. Neither total nor non-HDL serum cholesterol can predict stroke risk in the Japanese general population.


Ezaki O.,Showa Women's University | Miyake Y.,Fukuoka University | Sato S.,Chiba Prefectural Institute of Public Health | Iso H.,Osaka University
Journal of Nutritional Science and Vitaminology | Year: 2013

In the Dietary Reference Intakes (DRIs) for fat, adequate intake (AI) and tentative dietary goal for preventing lifestyle-related disease (DGs) were used. AIs were set for n-6 and n-3 polyunsaturated fatty acids, which are essential fatty acids because they are not produced by the human body and their deficiency leads to dermatitis. DGs have been set for total fat, saturated fat, n-6 fatty acids, n-3 fatty acids, and cholesterol, whose consumption levels affect risk of lifestyle-related disease, including obesity, diabetes mellitus, cardiovascular disease, and stroke. As AI for n-6 and n-3 polyunsaturated fatty acids, the 50th percentile of n-6 and n-3 fatty acid intake was set. In the Japanese population, 98% of dietary n-6 fatty acids come from linoleic acid; therefore the amount of n-6 fatty acid intake is considered to be that of linoleic acid. Both α-linolenic (60% of total n-3 fatty acids) acid and fish oils are considered essential fatty acids because it has been difficult to conclude that only α-linolenic acid is essential for humans. The prevention of diabetes mellitus and stroke was emphasized. For example, an increase in saturated fatty acids intake leads to increased incidences in obesity, diabetes, and myocardial infarction, whereas a decrease of saturated fatty acids intake is associated with increased incidence in brain hemorrhage. Therefore, DG of saturated fatty acids in those more than 18 y of age was set between 4.5 and 7% energy.


Yokoyama E.,Chiba Prefectural Institute of Public Health | Uchimura M.,Chiba Prefectural Institute of Public Health | Ito K.,National Institute of Infectious Disease
Journal of Food Protection | Year: 2010

A novel gene amplification method, loop-mediated isothermal amplification (LAMP), has been recently developed as a rapid, specific diagnostic method for various infectious diseases. We have investigated whether LAMP can be used to detect small numbers of enteroaggregative Escherichia coli (EAEC) cells contaminated in food samples. Primers for LAMP reaction were designed with EAEC aggR gene sequences (available in GenBank). LAMP specificity with these primers was the same as that of PCR in a study of 37 EAEC and 42 non-EAEC bacterial strains. The sensitivity of the LAMP method was better than that of PCR in a study of serially diluted EAEC cells. The LAMP method was significantly more effective than was PCR in detecting EAEC-contaminated food samples (Fisher's exact test, P < 0,05). Therefore, the LAMP method described here should be useful for detecting small numbers of EAEC cells in food samples. Copyright © International Association for Food Protection.


Yokoyama E.,Chiba Prefectural Institute of Public Health | Hachisu Y.,Chiba Prefectural Institute of Public Health | Hashimoto R.,Chiba Prefectural Institute of Public Health | Kishida K.,Chiba Prefectural Institute of Public Health
Infection, Genetics and Evolution | Year: 2012

Population genetic analysis using variable-number tandem repeat (VNTR) data of 23 loci (15 " optimized MIRU" loci and eight " Beijing option" loci) was done on Mycobacterium tuberculosis Beijing lineage strains isolated in Japan. These strains were divided into Beijing subgroups (B SUB) B1-B5 and T2 by minimum spanning tree (MST) analysis. The Φ PT values among the B SUB, a measure of their molecular variance, were significantly different from zero with 999 permutations, indicating the validity of B SUB classification using the 23 VNTR loci. Higher number of migrants (Nm) values were observed between B1 and T2, B4 and T2, B3 and T2, and B3 and B4 in a phylogenetic network model reconstructed from previously reported single-nucleotide polymorphism (SNP) data. These B SUB combinations, except B3 and B4, shared SNP types; i.e., ST19 was in B1 and T2 and in B4 and T2, and STK was in B3 and T2. These results taken together suggested that shared SNP types were not due to homoplasy, but to strong genetic relatedness between those B SUB. Haploid genetic diversity and standardized index of association values were different in each B SUB, indicating that the diversity of each B SUB was different. Although the differences in B SUB diversity were mostly in accordance with the relative divergence order of the B SUB in a phylogenetic network model, the diversity of B4 was biased by a significant increase in the number of strains in this study from patients born after 1964 (Fisher's exact test P<0.01). The different diversity of each B SUB indicated increased diversity of Beijing lineage strains, perhaps contributing to the survival and dissemination of these strains. © 2011 Elsevier B.V..


Yokoyama E.,Chiba Prefectural Institute of Public Health | Hachisu Y.,Chiba Prefectural Institute of Public Health | Hashimoto R.,Chiba Prefectural Institute of Public Health | Kishida K.,Chiba Prefectural Institute of Public Health
Infection, Genetics and Evolution | Year: 2010

Variable-number tandem repeat (VNTR) and large sequence polymorphism (LSP) analyses were compared to determine whether VNTR analysis was effective for population genetic analysis of Mycobacterium tuberculosis strains. A total of 682 strains, 510 Beijing genotype and 172 non-Beijing genotype strains, were studied.The number of repeats was investigated for 24 VNTR loci: the 15 loci of " optimized miru" , the 8 loci of " Beijing option" , and 1 locus for " JATA12" Six loci (miru31, Mtub4, QUB4156c, QUB3232, VNTR3820, and VNTR4120) showed significantly different median numbers of repeats in strains belonging to different lineages defined by LSP (P<0.01, Mann-Whitney U test). When a minimum-spanning tree (MST) was reconstructed using these 6 loci, most strains clustered in the expected branches in the MST branches. However, topology of the MST was not congruent with the evolutional hypothesis of M. tuberculosis, indicating that MST analysis using VNTR data should not use for phylogeny of the organism.When the standardized index of association (sIA) was calculated using data for the 6 VNTR loci, the value of sIA was significantly different from zero (Monte Carlo simulation with 10,000 resamplings) in every lineage, indicating the linkage disequilibrium in different lineage strains of M. tuberculosis. These results were consistent with the hypothesis that clonal evolution of lineages of the organism has occurred.Therefore, the 6 loci identified in this study would be effective for M. tuberculosis population genetic analysis due to their significantly different median numbers of repeat and linkage disequilibrium though VNTR data was not effective for phylogeny of the organism. © 2010 Elsevier B.V.


Sajiki J.,Chiba Prefectural Institute of Public Health
Nippon eiseigaku zasshi. Japanese journal of hygiene | Year: 2010

OBJECTIVE: To assess the risk of bisphenol A (BPA) exposure when infants suck or chew infant books, the concentration of BPA leaching from infant books published by Japanese makers to artificial saliva was measured. METHODS: The concentration of BPA leaching from 10 infant books to 15 ml artificial saliva or water was measured at 37 degrees C for 20 hrs. BPA concentration was measured by high-performance liquid chromatography-electrochemical detection (HPLC-ECD) with solid-phase extraction. RESULTS: BPA was leached from all books when pieces of them were dipped both into saliva and water for 20 hrs. The highest concentration of BPA leaching from one out of 10 books was 43.4 ng/ml (for 2 hrs) in saliva, which was estimated to be approximately 0.052 mg/kg body weight/day for infants aged 6-10 months. CONCLUSION: As BPA has endocrine-disrupting effects and poses higher risks in infants than in adults, it is desired to reduce BPA use in the printing of infant books from the viewpoint of child health.


Hachisu Y.,Chiba Prefectural Institute of Public Health
Rinsho byori. The Japanese journal of clinical pathology | Year: 2013

Variable number of tandem repeats (VNTR) analysis is one of the methods for molecular epidemiological studies of Mycobacterium tuberculosis. VNTR analysis is a method based on PCR, provides rapid highly reproducible results and higher strain discrimination power than the restriction fragment length polymorphism (RFLP) analysis widely used in molecular epidemiological studies of Mycobacterium tuberculosis. Genetic lineage compositions of Mycobacterium tuberculosis clinical isolates differ among the regions from where they are isolated, and allelic diversity at each locus also differs among the genetic lineages of Mycobacterium tuberculosis. Therefore, the combination of VNTR loci that can provide high discrimination capacity for analysis is not common in every region. The Japan Anti-Tuberculosis Association (JATA) 12 (15) reported a standard combination of VNTR loci for analysis in Japan, and the combination with hypervariable (HV) loci added to JATA12 (15), which has very high discrimination capacity, was also reported. From these reports, it is thought that data sharing between institutions and construction of a nationwide database will progress from now on. Using database construction of VNTR profiles, VNTR analysis has become an effective tool to trace the route of tuberculosis infection, and also helps in decision-making in the treatment course. However, in order to utilize the results of VNTR analysis effectively, it is important that each related organization cooperates closely, and analysis should be appropriately applied in the system in which accurate control and private information protection are ensured.


Yokoyama E.,Chiba Prefectural Institute of Public Health | Hirai S.,Chiba Prefectural Institute of Public Health | Hashimoto R.,Chiba Prefectural Institute of Public Health | Uchimura M.,Chiba Prefectural Institute of Public Health
Infection, Genetics and Evolution | Year: 2012

Enterohemorrhagic Escherichia coli serotype O157:H7/H-(O157) strains isolated in Chiba prefecture, Japan, during 2002-2009 were studied by lineage, subgroup, cluster, and clade analysis. Lineage analysis of 470 O157 strains with no known epidemiological relationships using lineage specific polymorphism assay-6 showed that there were 242 lineage I strains, 160 lineage I/II strains, 67 lineage II strains, and 1 atypical strain. Clade analysis of these strains by single nucleotide polymorphism in eight loci showed that lineage I contained all the clade 1, clade 2, and clade 3 strains, and some of the clade 4/5 strains. In contrast, clade 7, clade 8, and the remaining clade 4/5 strains were divided between lineage I/II and II, and clade 6 was in lineage I/II, suggesting paraphyletic evolution of these lineages. Cluster and subgroup analysis of the stx phage insertion site showed that all lineage I strains were cluster 3 and all lineage I/II and II strains, with the exception of clade 9, were in cluster 1. Clade analysis also indicated that there were three phylogenetic groups of clade 4/5 strains: ancestral groups containing lineage I/IIand II strains and a descendant group containing lineages I. Analysis of stx2c gene distribution showed that stx2c was in ancestral clade 4/5 strains but not in descendant 4/5 strains, suggesting that the ancestral group may be clade 4 as reported by Manning et al. The results with the markers used in this study suggested that the hierarchy of O157 phylogenetic relationships was lineage as the upper level, followed by subgroup and then cluster, and clade as the lowest level. The need for refinement of clade definition and modification of the model of the O157 evolution have been discussed. © 2012 Elsevier B.V.

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