Nationwide Molecular Epidemiology of Measles Virus in Japan Between 2008 and 2017.

Genotyping evidence that supports the interruption of endemic measles virus (MV) transmission is one of the essential criteria to be verified in achieving measles elimination. In Japan since 2014, MV genotype analyses have been performed for most of the measles cases in prefectural public health institutes nationwide. With this strong molecular epidemiological data, Japan was verified to have eliminated measles in March, 2015.

Association of maternal serum concentration of hydroxylated polychlorinated biphenyls with maternal and neonatal thyroid hormones: The Hokkaido birth cohort study.

Background: Evidence on the toxicity of hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) for thyroid hormones (TH) is limited, and the underlying mechanism remains unknown.

Objectives: We aimed to investigate the effects of environmental prenatal exposure to OH-PCBs and maternal and neonatal TH levels, taking the maternal-fetal TH transfer into account.

Methods: In this prospective birth cohort (the "Hokkaido study") we included 222 mother-neonate pairs.

Sex-related differences in the associations between maternal dioxin-like compounds and reproductive and steroid hormones in cord blood: The Hokkaido study.

Background: Prenatal exposure to dioxin-like compounds (DLCs) irreversibly affects fetal reproductive and steroid hormone synthesis.

Objective: This study aimed to assess the relationships between maternal DLCs and cord blood reproductive and steroid hormones.

Methods: Participants in this study were pregnant women who enrolled in the Sapporo Cohort of the Hokkaido Study between 2002 and 2005.

Association of prenatal exposure to PCDD/Fs and PCBs with maternal and infant thyroid hormones: The Hokkaido Study on Environment and Children's Health.

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) are persistent organic pollutants that are universally detected. Some congeners of PCDDs, PCDFs or PCBs have dioxin-like toxicity, whereas non-dioxin-like PCBs are considered to have different toxicity. Reports of the relationships between prenatal exposure to PCDDs, PCDFs or PCBs and thyroid homeostasis in pregnant women and infants have been inconsistent.

Current state of yusho and prospects for therapeutic strategies.

The mass food poisoning incident yusho occurred in Japan in 1968. It was caused by the ingestion of rice bran oil contaminated with polychlorinated biphenyls and various dioxins and dioxin-like compounds including polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDFs). Notably, PCDFs were found to contribute to approximately 65% of the total toxicity equivalent in the blood of yusho patients.

Compound-specific isotopic and congener-specific analyses of polychlorinated biphenyl in the heat medium and rice oil of the Yusho incident.

Compound-specific isotope analysis (CSIA) can be used to examine the source and transformation processes of organic pollutants in the environment. We performed a carbon stable isotope analysis of polychlorinated biphenyl (PCB) congeners in the PCB heat-transfer medium (heat medium) and the original Kanechlor-400 (KC-400, a commercial brand of PCBs) involved in the Yusho incident. The main purpose is to investigate whether isotope fractionation occurred in the rice oil deodorization process that caused the incident.

Gender-specific association of exposure to non-dioxin-like polychlorinated biphenyls during pregnancy with methylation levels of H19 and long interspersed nuclear element-1 in cord blood in the Hokkaido study.

Background: Associations between prenatal exposure to polychlorinated biphenyls (PCBs) and reduced birth-size, and between DNA methylation of insulin-like growth factor-2 (IGF-2), H19 locus, and long interspersed nuclear element-1 (LINE-1) and reduced birth-size are well established. To date, however, studies on the associations between prenatal exposure to PCBs and alterations in methylation of IGF-2, H19, and LINE-1 are lacking. Thus, in this study, we examined these associations with infant-gender stratification.

Prenatal exposure to dioxin-like compounds is associated with decreased cord blood IgE and increased risk of wheezing in children aged up to 7years: The Hokkaido study.

Introduction: In utero exposure to dioxin-like compounds (DLCs) may cause imbalance of immune development in early infancy. However, there are few epidemiological studies into the effects of in utero exposure to DLCs on allergies and infections during childhood. This study evaluates associations between concentrations of maternal DLCs and cord blood immunoglobulin (Ig) E, as well as allergies and infections during childhood.

Accumulation properties of polychlorinated biphenyl congeners in Yusho patients and prediction of their cytochrome P450-dependent metabolism by in silico analysis.

In what has become known as the Yusho incident, thousands of people in western Japan were poisoned by the accidental ingestion of rice bran oil contaminated with polychlorinated biphenyls (PCBs) and various dioxins and dioxin-like compounds. In this study, we investigated the accumulation patterns of 69 PCB congeners in the blood of Yusho patients in comparison with those of non-exposed controls. The blood samples were collected at medical check-ups in 2004 and 2005.

Dioxin-metabolizing genes in relation to effects of prenatal dioxin levels and reduced birth size: The Hokkaido study.

Objectives: We investigated the effects of maternal polymorphisms in 3 genes encoding dioxin-metabolizing enzymes in relation to prenatal dioxin levels on infant birth size in Japan.

Methods: We examined the relationship between dioxin exposure and birth size in relation to the polymorphisms in the genes encoding aromatic hydrocarbon receptor (AHR [G>A, Arg554Lys]), cytochrome P450 (CYP) 1A1 (T6235C), and glutathione S-transferase mu 1 (GSTM1; Non-null/null) in 421 participants using multiple linear regression models.

Results: In mothers carrying the GSTM1 null genotype, a ten-fold increase in total dioxin toxic equivalency was correlated with a decrease in birth weight of -345g (95% confidence interval: -584, -105).

Change in decay rates of dioxin-like compounds in Yusho patients.

Background: Once ingested, dioxins and dioxin-like compounds are excreted extremely slowly. Excretion can be evaluated by its half-life. Half-lives estimated from observed concentrations are affected by excretion and ongoing exposure.

Unexpectedly long half-lives of blood 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) levels in Yusho patients.

Background: Dioxins and dioxin-like compounds have half-lives typically between 7.2 years and 15 years. Our previous study of patients poisoned by extremely high concentrations of 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) in the 'Yusho incident' in 1968 found that in some the half-life of blood 2,3,4,7,8-PeCDF tended towards infinity.

[Blood PCB Concentrations and their Tendencies Examined in Fukuoka 2011-2014 Annual Inspections for Yusho].

We measured PCBs of blood of 154 people in the Yusho medical check-up from January 2011 through December 2014 and analyzed their PCB blood patterns. Eleven examinees were newly certified as Yusho patients during these 4 years. Of these 11, we identified three Yusho patients with the A pattern, five with the B pattern, and three with the BC pattern.

[The Distribution of Dioxin Concentrations in the Blood of Yusho Patients].

In 1968, the contamination of cooking oil by heat-degraded polychlorinated biphenyls (PCBs) caused a case of mass poisoning, the so-called Yusho incident. The cause of Yusho disease is thought to be ingested toxic substances, including not only PCBs but also polychlorinated dibenzofuran (PCDFs) in Kanemi rice oil. We previously measured dioxins concentrations in the blood of 854 Yusho patients by annual medical examination from 2001 to 2013.

[Relationships between Half-Lives of Dioxins and SNPs in AhR among Yusho Patients].

Half-lives of blood levels of 2,3,4,7,8-Pentachlorodibenzofuran (PeCDF) are varied in Yusho patients. The objective was to evaluate a relationship between half-lives of PeCDF levels and types of SNP rs10249788 of aryl hydrocarbon receptor (AHR) gene in 93 Yusho patients. Based on physical symptoms, age, sex, body mass index and other factors, we set up suitable calculation formulas to fit the actual PeCDF levels thorough rates of change in PeCDF.

Effects of in utero exposure to polychlorinated biphenyls, methylmercury, and polyunsaturated fatty acids on birth size.

The adverse effects of in utero exposure to polychlorinated biphenyls (PCBs) or methylmercury (MeHg), and the beneficial effects of nutrients from maternal fish intake might have opposing influences on fetal growth. In this study, we assessed the effects of in utero exposure to PCBs and MeHg on birth size in the Japanese population, which is known to have a high frequency of fish consumption. The concentrations of PCBs and polyunsaturated fatty acids in maternal blood, and the total mercury in hair (as a biomarker of MeHg exposure) were measured during pregnancy and at delivery.

Demographic, behavioral, dietary, and socioeconomic characteristics related to persistent organic pollutants and mercury levels in pregnant women in Japan.

Persistent organic pollutants and mercury are known environmental chemicals that have been found to be ubiquitous in not only the environment but also in humans, including women of reproductive age. The purpose of this study was to evaluate the association between personal lifestyle characteristics and environmental chemical levels during the perinatal period in the general Japanese population. This study targeted 322 pregnant women enrolled in the Hokkaido Study on Environment and Children's Health.

[Examination of alkali digestion temperature in isomer specific analysis of PCB in whole blood sample].

We compared concentrations of PCB congeners between conventional 80 degrees C alkali digestion method and 30 degrees C alkali digestion method using 22 individual blood samples collected during 2009 annual Yusho examinations. The mean concentration of tri-CB in 30 degrees C alkali digestion method was lower than that of conventional method. However, concentration of total PCBs, 2,3',4,4',5-pentaCB (PCB118), 2,2',4,4',5,5'-hexaCB (PCB153) and 2,3,3',4,4', 5-hexaCB (PCB156), which were used as index for Yusho diagnosis, were equivalent between the methods.

Concentration of hydroxylated polychlorinated biphenyls (OH-PCBs) in the blood of Yusho patients in 2010.

Hydroxylated polychlorinated biphenyls (OH-PCBs) are formed as major metabolites of PCBs by cytochrome P450 enzyme-mediated oxidation. It has been reported that their total concentration in serum samples of Yusho patients ranged from 390 to 1300 pg/g. We measured the concentration of OH-PCBs in blood collected from 183 Yusho patients living in Japan in 2010.

Improvement of measurement method for hydroxylated polychlorinated biphenyls (OH-PCBs) in blood samples using LC/MS/MS.

Hydroxylated polychlorinated biphenyls (OH-PCBs) are well known as metabolites of PCBs in the human body. We improved a measurement method for OH-PCBs in blood samples using LC/MS/MS. A new 2 microm particle column was used, and the analytical conditions for the LC/MS/MS measurements were optimized.

The changes in dioxin concentrations in the blood of Yusho patients from 2004 to 2010.

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in blood collected from Yusho patients during medical health examinations performed from 2004 to 2010. Out of the 242 and 200 Yusho patients who received medical health examinations in 2004 and 2010, respectively, the concentrations of PCDDs, PCDFs, and PCBs in the blood of 136 patients were measured in both of those years. The concentrations of individual congeners of PCDDs, PCDFs, and PCBs in the blood of these 136 Yusho patients measured in 2004 were compared with those measured in 2010.

Development of a newly large-volume injection system for dioxin determinations in blood of Yusho patients.

We developed a more effective method to measure the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and non-ortho-coplanar polychlorinated biphenyls (non-ortho PCBs) in the blood of Yusho patients using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) equipped with a newly large-volume injection system. The new injection system linked a LaviStoma system with a unique stomach-shaped inlet liner (SSIL) and a solvent-cut large-volume (SCLV) injection system. This approach made it possible to introduce volumes up to 200 microl into the HRGC/HRMS in comparison with the 20microl volume of the previously reported conventional SCLV method.