AbstractPatterns in the correlated evolution of parental care and life history traits are long established but controversial. Although parental care is related to large egg size in many taxa, conflicting results have also been reported. To test the evolutionary relationships between parental care and life history traits, we performed phylogenetic comparative analyses using shield bugs (Heteroptera: Acanthosomatidae), in which maternal guarding of eggs and young has repeatedly evolved.
View Article and Find Full Text PDFMany epidemiological studies have been conducted to investigate the health effects of low-dose radiation. Most of these investigations have focused on cancer, and fewer studies have examined non-cancer topics than cancer subjects. The purpose of this study is to compare the relative risks of non-cancer mortality from low-dose radiation with lifestyle factors (such as smoking habits) and socioeconomic status (such as years of education).
View Article and Find Full Text PDFThe health effects of low-dose radiation exposure have been a source of controversy. One possible reason is that epidemiological studies that compare radiation risk with other factors, such as lifestyle or socioeconomic status, have been limited. The aim of this study is to conduct a comparison of the cancer risk of mortality between radiation, lifestyle habits (such as smoking), and socioeconomic status (such as years of education) among Japanese nuclear workers.
View Article and Find Full Text PDFA number of epidemiological studies have been conducted to investigate the health effects of low-dose radiation. The author reviewed epidemiological studies among radiologists, radiological technologists, and nuclear workers. Because the results of many epidemiological studies on these subjects have been published, and many studies have measured radiation doses, there is little uncertainty.
View Article and Find Full Text PDFThe Japanese Epidemiological Study on Low-Dose Radiation Effects (J-EPISODE) has been conducted since 1990 by the Radiation Effects Association to analyse health effects for nuclear workers. It uses the recorded doses, i.e.
View Article and Find Full Text PDFAn evaluation of cancer risk based on organ-absorbed dose is underway for the Japanese Epidemiological Study on Low-Dose Radiation Effects (J-EPISODE), which has analyzed health effects in association with radiation exposure evaluated with the personal dose equivalent Hp(10). Although the concept of effective dose and its operational definition of Hp(10) are widely used for radiological protection purposes, effective dose is not recommended for epidemiological evaluation. Organ-absorbed dose was instead adopted for the IARC 15-Country Collaborative study (15-Country study), the International Nuclear Workers Study (INWORKS), the Mayak worker study, and the Life Span Study (LSS) of atomic bomb survivors.
View Article and Find Full Text PDFIn order to reconstruct organ-absorbed dose from recorded dose for risk estimation in nuclear worker cohort, the preceding study of the International Agency for Research on Cancer (IARC) 15-Country Collaborative Study estimated the organ dose conversion factor from the recorded dose of Hp(10) under the assumption that on average, in the nuclear power plants (NPPs), 10% of the dose received by workers was due to photon energies ranging from 100 to 300 keV and 90% from photon energies ranging from 300 to 3000 keV, with the average geometry being 50% in the antero-posterior geometry and 50% in the isotropic geometry. Similar examination was conducted at the Japanese Epidemiological Study on Low-Dose Radiation Effects (J-EPISODE). Literature survey disclosed that Japanese electric power companies had jointly conducted the research on energy distribution and incidence direction distribution of gamma rays in working environments during periodical inspection and maintenance as well as during operation in the 1980s.
View Article and Find Full Text PDFEstimation of cancer risk based on the organ-absorbed dose is underway for the Japanese Epidemiological Study on Low-Dose Radiation Effects (J-EPISODE). The reconstruction method for the organ-absorbed dose follows the approach adopted in the IARC 15-Country Collaborative Study, which examined the dosemeter response to photon exposure for the old film badge (FB) type, a multi-element FB and a thermoluminescence dosemeter. Until 2000, the dosemeters used in Japan were almost the same in the IARC study, so IARC study data could be used as they were.
View Article and Find Full Text PDFThe excess relative risk (ERR) of mortality for circulatory disease among nuclear workers was reanalyzed by taking into consideration the annual dose as the dose rate using publicly available epidemiological data of the Hanford site dedicated to the cohort study of nuclear workers in the US, the UK, and Canada. Values of the dose rate (cut-points) were chosen at 2 mSv y intervals from 2 to 40 mSv y, and risk estimates were made for 32,988 workers, considering the doses accumulated below and above each cut-point to have different effects. Similarly to that in the previous study for cancer by Sasaki et al.
View Article and Find Full Text PDFThe excess relative risk of mortality for all cancers excluding leukemia among nuclear workers was reanalyzed by taking the annual dose as the dose rate into consideration using publicly available epidemiological data from the Hanford site dedicated to the cohort study of nuclear workers in the United States, the United Kingdom, and Canada (Three Countries Study). Values of the dose rate (cut points) were chosen at 2 mSv y intervals from 2 to 40 mSv y, and risk estimates were made for 32,988 workers, considering doses accumulated below the cut point and above the cut point to have different effects. Although the procedure to extract the study population and the methodology used for analysis basically followed those in the Three Countries Study, additional examinations were also carried out for different risk models, lag periods, and impacts of adjusting the monitoring period to find the effect of the dose rate.
View Article and Find Full Text PDFSexual traits are subject to evolutionary forces that maximize reproductive benefits and minimize survival costs, both of which can depend on environmental conditions. Latitude explains substantial variation in environmental conditions. However, little is known about the relationship between sexual trait variation and latitude, although body size often correlates with latitude.
View Article and Find Full Text PDFWe found some trivial errors which might confuse reader. The errors can be identified as the following two types. (1) The one is that misuse of "ERR" and "ERR/Sv".
View Article and Find Full Text PDFA causal relationship between protracted exposure to low-dose rate radiation and health effects remains unclear despite extensive international studies of nuclear workers. One potential reason is that radiation epidemiological studies that adjust for tobacco smoking, which heavily influences mortality, have been limited. In the present study, we examined radiation-related cancer risk by directly assessing the possible confounding effect of smoking, using data from two questionnaire surveys performed among Japanese nuclear workers in 1997 and 2003.
View Article and Find Full Text PDFPaternal care can be maintained under sexual selection, if it helps in attracting more mates. We tested the hypothesis in two giant water bug species, Appasus major and Appasus japonicus, that male parental care is sexually selected through female preference for caring males. Females were given an opportunity to choose between two males.
View Article and Find Full Text PDFBackground: Maternal care (egg-nymph guarding behavior) has been recorded in some genera of Acanthosomatidae. However, the origin of the maternal care in the family has remained unclear due to the lack of phylogenetic hypotheses. Another reproductive mode is found in non-caring species whose females smear their eggs before leaving them.
View Article and Find Full Text PDFThe rapid determination system of viral genome sequences (the RDV method) consists of detecting and determining the nucleotide sequences of viral genomes without using specific primers. To evaluate the usefulness of the RDV method, the detection of human norovirus (NV) genomes in stool specimens was investigated. In addition, the effect of nuclease treatment of the process was examined.
View Article and Find Full Text PDFRett syndrome is a neurological, X chromosomal-linked disorder associated with mutations in the MECP2 gene. MeCP2 protein has been proposed to play a role in transcriptional regulation as well as in chromatin architecture. Since MeCP2 mutant cells exhibit surprisingly mild changes in gene expression, we have now explored the possibility that Rett mutations may affect the ability of MeCP2 to bind and organize chromatin.
View Article and Find Full Text PDFBackground: Rett syndrome is a neurodevelopmental and autistic disease caused by mutations of Methyl-CpG-binding protein 2 (MECP2) gene. MeCP2 protein is mainly expressed in neurons and binds to methylated gene promoters to suppress their expression, indicating that Rett syndrome is caused by the deregulation of target genes in neurons. However, it is likely that there are more unidentified neuronal MeCP2-targets associated with the neurological features of RTT.
View Article and Find Full Text PDFMutations of the methyl CpG binding protein 2 (MeCP2) gene are a major cause of Rett syndrome. To investigate whether the expression of this gene was related to JC virus (JCV) infection, we examined brains of four progressive multifocal leukoencephalopathy (PML) patients. JCV infection was confirmed by immunohistochemical labeling with antibodies against JCV VP1, agnoprotein and large T antigen.
View Article and Find Full Text PDFRett syndrome (RTT) is an X chromosome-linked neurodevelopmental disorder associated with the characteristic neuropathology of dendritic spines common in diseases presenting with mental retardation (MR). Here, we present the first quantitative analyses of dendritic spine density in postmortem brain tissue from female RTT individuals, which revealed that hippocampal CA1 pyramidal neurons have lower spine density than age-matched non-MR female control individuals. The majority of RTT individuals carry mutations in MECP2, the gene coding for a methylated DNA-binding transcriptional regulator.
View Article and Find Full Text PDFThe expression of the methylated DNA-binding protein MeCP2 increases during neuronal development, which suggests that this epigenetic factor is crucial for neuronal terminal differentiation. We evaluated dendritic and axonal development in embryonic day-18 hippocampal neurons in culture by measuring total length and counting branch point numbers at 4 days in vitro, well before synapse formation. Pyramidal neurons transfected with a plasmid encoding a small hairpin RNA (shRNA) to knockdown endogenous Mecp2 had shorter dendrites than control untransfected neurons, without detectable changes in axonal morphology.
View Article and Find Full Text PDFThe microsporidian Encephalitozoon cuniculi is a spore-forming, obligate, intracellular parasitic pathogen with a unique organelle called a polar tube, the extrusion of which is essential for invading a host cell. The polar tube consists of three proteins: polar tube protein 1 (PTP1), PTP2, and PTP3. We established three mouse monoclonal antibodies (MAb1, MAb2, and MAb4) against E.
View Article and Find Full Text PDFMeCP2, a methyl-CpG binding domain (MBD) protein, is known to bind to methylated CpG sites via a conserved MBD, leading to transcriptional repression. However, studies in cell-free system for gene repression and MeCP2 binding have suggested that DNA methylation-independent repression also occurs in living cells. It has been difficult to characterize the target genes of MeCP2 because a limited number have been identified to date.
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