Publications by authors named "Nakata Akifumi"

We investigated potential germline-specific radiosensitive biomarkers in the testes of large Japanese field mice (Apodemus speciosus) exposed to low-dose-rate (LDR) radiation after the Fukushima accident. Fukushima wild mice testes were analysed via RNA-sequencing to identify genes differentially expressed in the breeding and non-breeding seasons when compared to controls. Results revealed significant changes during the breeding season, with Lsp1 showing a considerable upregulation, while Ptprk and Tspear exhibited significant reductions.

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Article Synopsis
  • - The study explored how chronic low-dose-rate radiation affects gene expression related to immune defense and epigenetic regulation in male mice's testis.
  • - Results showed that exposure to radiation significantly reduced epigenetic regulation gene expression while increasing genes associated with innate and acquired immunity, indicating a strong impact on immune response.
  • - Additionally, there was a rise in the expression of the SRY-box transcription factor 9, which is vital for testicular development, highlighting the biological consequences of this radiation exposure.
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  • Cancer is a significant health issue globally, with millions dying each year, and cisplatin, a common chemotherapy drug, has considerable side effects.
  • The study explored the effects of Ganoderma lucidum, a traditional Chinese medicine, on reducing the toxicity caused by cisplatin in both cell cultures and mice.
  • Results showed that G. lucidum effectively reduced cisplatin-induced damage in cells and mice, likely due to its antioxidant properties, suggesting it could help lessen the negative effects of cisplatin treatment.
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  • The Fukushima Daiichi Nuclear Power Plant accident has prompted research into the effects of chronic low-dose-rate radiation exposure on biological systems, particularly its impact on the reproductive system and potential infertility.
  • A study was conducted on the testis ultrastructure of wild large Japanese field mice from contaminated areas with varying radiation levels, revealing preserved seminiferous tubules similar to unexposed controls, but with some structural changes.
  • Findings indicated increased lipid droplet clusters in spermatogenic cells and changes related to spermatogenesis, suggesting that while there were ultrastructural modifications, the overall process of spermatogenesis remained normal in mice exposed to low-dose radiation.
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The current study aimed to investigate the effects of ageing on oral immunity using -defensin (DEFB) 1/2 as a marker and evaluate the effects of curcumin (CUR) on these processes. The study sample included thirty male C57BL/6J mice divided into three groups based on the treatment method used. The young control (YC) and old control (OC) groups received 0·5 % methylcellulose-400 (CUR vehicle) orally for 5 days, whereas the CUR group of older mice received a CUR solution suspended in 0·5 % methylcellulose-400 (dose: 3·0 mg/kg body).

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Multiple epidemiological studies have shown that obesity is a serious risk factor for cancer development. While the underlying mechanisms between obesity and cancer are still unknown, obesity disrupts the role of adipocytes in energy homeostasis, and the alteration of adipokine, insulin and sex steroid signaling. Recently, it has been identified that adipose tissue-derived exosome-like vesicles (ELVs) regulate metabolic homeostasis.

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Background/aim: We investigated the effects of chloroquine, an autophagy inhibitor, on doxorubicin-induced apoptosis in A549 cells.

Materials And Methods: A549 cells were treated with doxorubicin, chloroquine, or both. Then, cytotoxicity was measured.

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Background/aim: We examined the inhibitory effect of mulberry leaf (ML) (Morus alba L.) administration on the development of hepatocellular carcinoma (HCC) in stelic animal model (STAM) mice. This STAM mouse model of nonalcoholic steatohepatitis (NASH) closely resembles the progression from NASH to HCC in human clinical practice.

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Wild large Japanese field mice () responses to cyclic seasonal changes are associated with physiological and behavioral changes. However, the detailed regulation of oogenesis in the ovary during the seasonal reproductive cycle in wild large Japanese field mice has not been studied. We assessed the dynamics and changes in ovarian morphology and hormone concentrations associated with reproductive seasonality throughout the year.

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The intergenerational effects from chronic low-dose exposure are matters of concern. It is thus important to elucidate the radiation-induced effects of germ cell maturation, fertilization and embryonic development. It is well known that DNA methylation levels in CpG sites in gametes are reprogrammed in stages during their maturity.

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Background/aim: We investigated the effect of Kumaizasa leaf extract (KLE) on innate immunity using the HEK293 and RAW 264.7 cell lines.

Materials And Methods: KLE, lipopolysaccharides (LPS), or KLE with LPS were added to RAW 264.

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We investigated the internal contamination by radioactive cesium associated with the FDNPP accident, in the testes or uterus and ovaries of free-roaming cats (), which were protected by volunteers in the Namie Town, Fukushima. A total of 253 samples (145 testes and 108 uterus and ovaries) obtained from adult cats and 15 fetuses from 3 pregnant female cats were measured. Free-roaming cats in Namie Town had a higher level of radioactive contamination in comparison to the control group in Tokyo, as the Cs + Cs activity concentration ranged from not detectable to 37,882 Bq kg in adult cats.

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Since the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, we have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of racoons from the ex-evacuation zone of the FDNPP accident.

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Article Synopsis
  • Alopecia often occurs after high-dose radiation, with neonatal mice exposed to 7 Gy X-ray showing hair growth defects, except on their cheeks.
  • The study investigates exosome-like vesicles (ELV) from cheek and back skin to explore their potential protective effects against radiation damage.
  • Results indicate that ELV from the cheek skin of irradiated mice helps prevent hair follicle loss, suggesting a protective role after radiation exposure.
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Purpose: In suspected radiation exposures, cytokinesis-block micronucleus (CBMN) assay is used for biodosimetry by detecting micronuclei (MN) in binucleated (BN) cells in whole blood and isolated peripheral blood mononuclear cell (PBMC) cultures. Standardized harvest protocols for whole blood were published by the International Atomic Energy Agency (IAEA) in 2001 (Technical report no. 405) and 2011 (EPR-Biodosimetry).

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Purpose: To study the environmental radiation effects of wild animals after the Fukushima Dai-ichi nuclear power plant accident, we assessed effects on hematopoietic progenitor cells (HPCs) in large Japanese field mice ().

Materials And Methods: A. speciosus were collected from three contaminated sites and control area.

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  • The study aimed to analyze the biological effects of chronic low dose-rate radiation on large Japanese field mice in contaminated areas around Fukushima following the 2011 nuclear accident.
  • Researchers collected mice from contaminated sites and control areas from 2011 to 2013, assessing chromosome aberrations through cell cultures.
  • Results showed no radiation-specific chromosome changes; however, some structural aberrations were noted with decreasing frequency over the years, indicating the potential of chromosome analysis to monitor radiation effects in wildlife.
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Cetaceans accumulate high levels of environmental pollutants, yet their toxicological studies have been difficult due to technical and ethical issues. It is essential to identify and fill the current knowledge gaps in the assays available for cetaceans. The present study establishes a novel assay that uses the fibroblasts of a finless porpoise () (FF) stranded in the Seto Inland Sea (SIS) to answer questions about the cytotoxicity and risks of environmental pollutants.

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The aim of this study was to investigate the proliferation and apoptosis of male germ cells during the seasonal reproductive cycle of the large Japanese field mice (Apodemus speciosus). Male mice residing in their natural habitat were captured in Niigata, Japan. Testis sections were stained with haematoxylin and eosin, and mitotic male germ cells were identified using immunofluorescence staining for proliferating cell nuclear antigen (PCNA).

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Seasonally, bred wild mice provide a unique bioresource, with high genetic diversity that differs from wild-derived mice and laboratory mice. This study aimed to establish an alternative superovulation method using wild large Japanese field mice (Apodemus speciosus) as the model species. Specifically, we investigated how the application of inhibin antiserum and equine chorionic gonadotropin (IASe) during both the reproductive and non-reproductive seasons impact the ovulation rate and competence of embryo development after in vitro fertilization (IVF) with fresh and cryopreserved sperm.

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Exosome-like vesicles (ELV) are involved in mediating radiation-induced bystander effect (RIBE). Here, we used ELV from control cell conditioned medium (CCCM) and from 4 Gy of X-ray irradiated cell conditioned medium (ICCM), which has been used to culture normal human fibroblast cells to examine the possibility of ELV mediating RIBE signals. We investigated whether ELV from 4 Gy irradiated mouse serum mediate RIBE signals.

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Biallelic germline mutations in the DNA mismatch repair gene MLH1 lead to constitutional mismatch repair-deficiency syndrome and an increased risk for childhood hematopoietic malignancies, including lymphoma and leukemia. To examine how Mlh1 dysfunction promotes lymphoma as well as the influence of ionizing radiation (IR) exposure, we used an Mlh1-/- mouse model and whole-exome sequencing to assess genomic alterations in 23 T-cell lymphomas, including 8 spontaneous and 15 IR-associated lymphomas. Exposure to IR accelerated T-cell lymphoma induction in the Mlh1-/- mice, and whole-exome sequencing revealed that IR exposure neither increased the number of mutations nor altered the mutation spectrum of the lymphomas.

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Purpose: In order to establish suitable protocols of blood culture to obtain sufficient numbers of metaphases for dicentric chromosome assay (DCA), we have examined the effect of storage temperature, storage time, and anticoagulant type.

Materials And Methods: Peripheral blood was collected from five healthy donors with lithium heparin and ethylenediaminetetraacetic acid dipotassium salt (EDTA-2K). These samples were irradiated with X-rays at 3 Gy or sham; the samples were further divided into groups that were either stored at room temperature (RT) or 5.

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Age at exposure is a critical factor that influences the risk of radiation-induced leukemia. Accumulating evidence suggests that ionizing radiation can induce genomic instability and promote leukemogenesis in hematopoietic stem cells (HSCs); however, the influence of age on this phenomenon has not been elucidated. In this study, infant (1-week-old) or adult (14-week-old) C3H/He mice received sham or 4 Gy whole-body irradiation, and bone marrow cells were transplanted to recipients at day 1 or 60 postirradiation.

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Background/aim: Mulberry (Morus alba L.) leaves (ML) contain many functional components, such as 1-deoxynojirimycin, flavonoids (rutin, quercetin, kaempferol). It is well known that 1-deoxynojirimycin functions to suppress increases in blood glucose level by α-glucosidase inhibitory activity.

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