Publications by authors named "Hiroyuki Imai"

Article Synopsis
  • * The study examined 132 bats from 4 species in Yamaguchi Prefecture using PCR methods to detect various viruses.
  • * Researchers identified herpesviruses, adenoviruses, astroviruses, and coronaviruses, finding 12 strains that are closely related to viruses from China and South Korea.
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The pecten is a fold-structured projection at the ocular fundus in bird eyes, showing morphological diversity between the diurnal and nocturnal species. However, its biological functions remain unclear. This study investigated the morphological and histological characteristics of pectens in wild birds.

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Exosomes or small extracellular vesicles (sEVs) are present in the blood of pregnant mice and considered to be involved in pregnancy physiology. Although sEVs in pregnant periods are proposed to be derived from placentas, sEVs-producing cells are not well known in mouse placentas. We studied the dynamics and localization of sEVs in pregnant serum and placentas, and examined gestational variation of microRNA (miRNA).

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Mus minutoides is one of the smallest mammals worldwide; however, the regulatory mechanisms underlying its dwarfism have not been examined. Therefore, we aimed to establish M. minutoides induced pluripotent stem cells (iPSCs) using the PiggyBac transposon system for applications in developmental engineering.

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In general, humoral factors released from the placenta influence pregnancy progression, but the involvement of the canine placenta is often unidentified. We investigated specific genes in canine placentas and analyzed the blood dynamics of the translated proteins. Furthermore, RNAs are known to be released from placentas embedding in exosomes, a type of extracellular vesicles.

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A convenient method for the determination of plant sphingolipids (glycosylinositol phosphoceramide, GIPC; glucosylceramide, GluCer; phytoceramide 1-phosphate, PC1P and phytoceramide, PCer) was developed. This method includes the extraction of lipids using 1-butanol, alkali hydrolysis with methylamine and separation by TLC. The amounts of sphingolipids in the sample were determined based on the relative intensities of standard sphingolipids visualized by primulin/UV on TLC.

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The African pygmy mouse ( ) displays a dwarfism phenotype distinctive from closely related species. This study aimed to investigate the growth hormone receptor (Ghr) gene sequence in . We identified several amino acid variations, including the P469L mutation.

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Mouse embryos in the early-implantation stage require manipulation under a microscope. While the extraction of DNA, RNA and proteins from a single sample allows for both determination of genetic type and analysis of gene expression, whole mount analysis is not possible. In this study, we explored the applicability of PCR using extraembryonic tissues, especially the decidual side tissue after isolating the embryos from implantation sites to establish a method for determining the genetic type of embryos.

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In mammals, immune tolerance against fetal tissue has been established for normal pregnancy progression. It is known that Crry regulates complemental activity to prevent injury of the mouse embryo and extra-embryonic tissue. This study aimed to examine the expression appearance and normal localization sites of Crry in the mouse placenta.

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Glycosylinositol phosphoceramide (GIPC) is a major sphingolipid in the plasma membranes of plants. Previously, we found an enzyme activity that produces phytoceramide 1-phosphate (PC1P) by hydrolysis of the D position of GIPC in cabbage and named this activity as GIPC-phospholipase D (PLD). Here, we purified GIPC-PLD by sequential chromatography from radish roots.

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The administration of a third booster dose of messenger ribonucleic acid (mRNA) vaccines against coronavirus disease 2019 (COVID-19) has progressed worldwide. Since January 2022, Japan has faced a nationwide outbreak caused by the Omicron variant, which occurred simultaneously with the progression of mass vaccination with the third booster dose. Therefore, this study evaluated the effectiveness of the third dose of vaccine by reverse transcription-polymerase chain reaction (RT-PCR) test using nasopharyngeal swab samples from adults aged ≥ 18 years tested after having close contact with COVID-19 cases between January and May 2022.

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Estrogen receptor α (ERα) is a transcription factor that induces cell proliferation and exhibits increased expression in a large subset of breast cancers. The molecular mechanisms underlying the up-regulation of ERα activity, however, remain poorly understood. We identified FK506-binding protein 52 (FKBP52) as a factor associated with poor prognosis of individuals with ERα-positive breast cancer.

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Vertebrates, including mammals, are considered to have evolved by whole genome duplications. Although some fish have been reported to be polyploids that have undergone additional genome duplication, there have been no reports of polyploid mammals due to abnormal development after implantation. Furthermore, as the number of physiologically existing tetraploid somatic cells is small, details of the functions of these ploidy-altered cells are not fully understood.

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The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remained a major global health concern in 2021. To suppress the spread of infection, mass vaccinations have been performed across countries worldwide. In Japan, vaccinations of the first and second doses for most of the nation were performed during the nationwide outbreak of the B.

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Ceramide (Cer) and glucosylceramide (GlcCer) were isolated from Satsuma mandarin (Citrus unshiu) fruits and characterized. 2,3-Dihydroxy fatty acids with C20 or longer acyl chains were found in Cer. GlcCers from the flesh of the fruit contained sphingosine (4-trans-sphingenine) as a major component.

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The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global public health concern in 2021. However, the risk of attending schools during the pandemic remains unevaluated. This study estimated the secondary transmission rate at schools using the results of a real-time reverse transcription-polymerase chain reaction (RT-PCR) screening test performed between July 2020 and April 2021, before starting the nationwide mass vaccination.

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In order to survive subzero temperatures, some plants undergo cold acclimation (CA) where low, nonfreezing temperatures, and/or shortened day lengths allow cold-hardening and survival during subsequent freeze events. Central to this response is the plasma membrane (PM), where low temperature is perceived and cellular homeostasis must be preserved by maintaining membrane integrity. Here, we present the first PM proteome of cold-acclimated Brachypodium distachyon, a model species for the study of monocot crops.

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Objective Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), remains the world's largest public health concern in 2021. A history of close contact with infectious patients is a factor that predicts a positive SARS-CoV-2 test result. Meanwhile, the precise predictive value of symptoms suggestive of COVID-19 has not been fully elucidated.

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Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is the world's largest public health concern in 2021. This study evaluated the associations of the prevalence of airway symptoms among the tested individuals and data regarding the natural environmental factors with the weekly number of newly diagnosed COVID-19 patients in Sendai City (N). For the derivatives of the screening test results, data from individuals with a contact history who underwent nasopharyngeal swab reverse transcription-polymerase chain reaction (RT-PCR) testing between July 2020 and April 2021 (6,156 participants, including 550 test-positive patients) were used.

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The large Japanese field mouse (Apodemus speciosus) is a small rodent species endemic to Japan. The genetic characteristics of A. speciosus include different chromosome numbers within the same species.

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We determined the nucleotide sequence of the growth hormone (Gh) gene in Mus minutoides, one of the smallest mammals, where was predicted to be distinct in the functional regions between M. minutoides and Mus musculus. To investigate the evolutionary characteristics of Gh in M.

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Our previous research has indicated local expression of ADAMDEC-1, a family of disintegrin and metalloproteinase, was confirmed in the mouse placentas and enhancement was found in the sites for spontaneous abortion. Present study was aimed to identify biological effects of ADAMDEC-1 in pregnancy process. Syngeneic pairs of C57BL/6J mice and heterogenic mating pairs of CBA/J and DBA/2 mice were used.

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In response to the COVID-19 pandemic caused by SARS-CoV-2 in 2020, we conducted drive-through nasopharyngeal swab testing for COVID-19 in Sendai city, Japan, since April 2020. All tested individuals were judged in advance by public health centers for the necessity of undergoing the test with possible contact history and/or symptoms suggestive of COVID-19. In this study, to identify the predictors of SARS-CoV-2 test positivity for more efficient and evidenced selection of suspected individuals, we enrolled 3,540 consecutive individuals, tested in the first 7 months of the testing program, with data regarding to the history of close contact with COVID-19 patients, including those involved in cluster outbreaks.

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Article Synopsis
  • In nocturnal mammals, rod cells have heterochromatin in the nucleus that helps efficiently direct light to photoreceptors.
  • The study focused on owl monkeys, particularly the species Aotus azarae, which was found to have a similar heterochromatin structure in its rod cells.
  • Analysis of another species, Aotus lemurinus, confirmed they also possess this feature, suggesting the heterochromatin block formed before the two species diverged, estimated to have occurred around 15 million years ago.
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