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result(s) for
"Hirai, Hisashi"
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Transport and release of chemicals from plastics to the environment and to wildlife
by
Barlaz, Morton A.
,
Zakaria, Mohamad P.
,
Imamura, Ayako
in
Adsorption
,
Animals
,
Benzhydryl Compounds
2009
Plastics debris in the marine environment, including resin pellets, fragments and microscopic plastic fragments, contain organic contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons, petroleum hydrocarbons, organochlorine pesticides (2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane, hexachlorinated hexanes), polybrominated diphenylethers, alkylphenols and bisphenol A, at concentrations from sub ng g1 to g g1. Some of these compounds are added during plastics manufacture, while others adsorb from the surrounding seawater. Concentrations of hydrophobic contaminants adsorbed on plastics showed distinct spatial variations reflecting global pollution patterns. Model calculations and experimental observations consistently show that polyethylene accumulates more organic contaminants than other plastics such as polypropylene and polyvinyl chloride. Both a mathematical model using equilibrium partitioning and experimental data have demonstrated the transfer of contaminants from plastic to organisms. A feeding experiment indicated that PCBs could transfer from contaminated plastics to streaked shearwater chicks. Plasticizers, other plastics additives and constitutional monomers also present potential threats in terrestrial environments because they can leach from waste disposal sites into groundwater and/or surface waters. Leaching and degradation of plasticizers and polymers are complex phenomena dependent on environmental conditions in the landfill and the chemical properties of each additive. Bisphenol A concentrations in leachates from municipal waste disposal sites in tropical Asia ranged from sub g l1 to mg l1 and were correlated with the level of economic development.
Journal Article
Modulation of the tumor microenvironment by Epstein‐Barr virus latent membrane protein 1 in nasopharyngeal carcinoma
2018
Latent membrane protein 1 (LMP1) is a primary oncogene encoded by the Epstein‐Barr virus, and various portions of LMP1 are detected in nasopharyngeal carcinoma (NPC) tumor cells. LMP1 has been extensively studied since the discovery of its transforming property in 1985. LMP1 promotes cancer cell growth during NPC development and facilitates the interaction of cancer cells with surrounding stromal cells for invasion, angiogenesis, and immune modulation. LMP1 is detected in 100% of pre‐invasive NPC tumors and in approximately 50% of advanced NPC tumors. Moreover, a small population of LMP1‐expressing cells in advanced NPC tumor tissue is proposed to orchestrate NPC tumor tissue maintenance and development through cancer stem cells and progenitor cells. Recent studies suggest that LMP1 activity shifts according to tumor development stage, but it still has a pivotal role during all stages of NPC development. Epstein‐Barr virus LMP1 is a primary oncogene that transform various mammalian cells. LMP1 also modulates nasopharyngeal carcinoma microenvironment and contributes NPC development.
Journal Article
Phosphoribosyl pyrophosphate amidotransferase: Novel biomarker and therapeutic target for nasopharyngeal carcinoma
by
Shigetaka Komura
,
Satoru Kondo
,
Hirotomo Dochi
in
Amidophosphoribosyltransferase - genetics
,
Amidophosphoribosyltransferase - metabolism
,
Biomarkers
2024
Cancer cells show a dynamic metabolic landscape, requiring a sufficient supply of nucleotides to proliferate. They are highly dependent on de novo purine biosynthetic pathways for their nucleotide requirements. Phosphoribosyl pyrophosphate amidotransferase (PPAT), catalyzing the first step of de novo purine biosynthesis, is highly expressed in various cancers. We observed an increased expression of PPAT in nasopharyngeal carcinoma (NPC). Moreover, our ribonucleic acid sequencing analysis showed high PPAT expression in Epstein–Barr virus‐positive NPC, which was supported by in vitro analysis. Through a gene knockdown study, we showed that the suppression of PPAT expression reduced the proliferation and invasion of NPC cells. We also demonstrated the regulation of PPAT by glutamine, a cosubstrate for PPAT. A glutamine antagonist, 6‐diazo‐5‐oxo‐L‐norleucine, blocked glutamine‐mediated induction of PPAT and reduced NPC cell proliferation. Immunohistochemical analysis of PPAT in NPC tissues revealed increased expression of PPAT with disease progression, which was significantly associated with poor prognosis. In summary, this study highlighted the biological function of PPAT in NPC, establishing its potential as a novel prognostic biomarker for aggressive NPC and a promising therapeutic target. We investigated the role of phosphoribosyl pyrophosphate amidotransferase (PPAT) in nasopharyngeal carcinoma (NPC), revealing heightened PPAT expression in Epstein–Barr virus‐positive NPC. The research establishes PPAT as a crucial factor influencing NPC cell proliferation and invasion, with glutamine identified as a key regulator; the study suggests PPAT as a potential prognostic biomarker and therapeutic target for aggressive NPC.
Journal Article
EBV genome variations enhance clinicopathological features of nasopharyngeal carcinoma in a non‐endemic region
2022
Nasopharyngeal carcinoma (NPC) is caused by infection with Epstein–Barr virus (EBV) and endemic in certain geographic regions. EBV lytic gene, BALF2, closely associates with viral reactivation and BALF2 gene variation, the H‐H‐H strain, causes NPC in endemic region, southern China. Here, we investigate whether such EBV variations also affect NPC in a non‐endemic region, Japan. Viral genome sequencing with 47 EBV isolates of Japanese NPC were performed and compared with those of other EBV‐associated diseases from Japan or NPC in Southern China. EBV genomes of Japanese NPC are different from those of other diseases in Japan or endemic NPC; Japanese NPC was not affected by the endemic strain (the BALF2 H‐H‐H) but frequently carried the type 2 EBV or the strain with intermediate risk of endemic NPC (the BALF2 H‐H‐L). Seven single nucleotide variations were specifically associated with Japanese NPC, of which six were present in both type 1 and 2 EBV genomes, suggesting the contribution of the type 2 EBV‐derived haplotype. This observation was supported by a higher viral titer and stronger viral reactivation in NPC with either type 2 or H‐H‐L strains. Our results highlight the importance of viral strains and viral reactivation in the pathogenesis of non‐endemic NPC. Epstein–Barr virus (EBV) genome variation such as BALF2 that is associated with viral reactivation is a risk factor of nasopharyngeal carcinoma (NPC) in endemic regions such as southern China. We found unique BALF2 genome variation in EBV isolates of NPC in Japan, an non‐endemic region, different from endemic NPC. We revealed the importance of viral strains and their reactivation in the pathogenesis of non‐endemic NPC.
Journal Article
Estrogen induces the expression of EBV lytic protein ZEBRA, a marker of poor prognosis in nasopharyngeal carcinoma
by
Hamabe‐Horiike, Toshihide
,
Wakae, Kousho
,
Nakanishi, Yosuke
in
Acetic acid
,
Antibodies
,
Apoptosis
2022
Several epidemiological studies have suggested that Epstein–Barr virus (EBV) lytic infection is essential for the development of nasopharyngeal carcinoma (NPC), as the elevation of antibody titers against EBV lytic proteins is a common feature of NPC. Although ZEBRA protein is a key trigger for the initiation of lytic infection, whether its expression affects the prognosis and pathogenesis of NPC remains unclear. In this study, 64 NPC biopsy specimens were analyzed using immunohistochemistry. We found that ZEBRA was significantly associated with a worsening of progression‐free survival in NPC (adjusted hazard ratio, 3.58; 95% confidence interval, 1.08–11.87; p = 0.037). Moreover, ZEBRA expression positively correlated with key endocrinological proteins, estrogen receptor α, and aromatase. The transcriptional level of ZEBRA is activated by estrogen in an estrogen receptor α‐dependent manner, resulting in an increase in structural gene expression levels and extracellular virus DNA copy number in NPC cell lines, reminiscent of lytic infection. Interestingly, it did not suppress cellular proliferation or increase apoptosis, in contrast with cells treated with 12‐O‐tetradecanoylphorbol‐13‐acetate and sodium butyrate, indicating that viral production induced by estrogen is not a cell lytic phenomenon. Our results suggest that intratumoral estrogen overproduced by aromatase could induce ZEBRA expression and EBV reactivation, contributing to the progression of NPC. We have revealed that EBV lytic protein ZEBRA is significantly associated with poor prognosis of nasopharyngeal carcinoma. Moreover, our study suggests that locally expressed intratumoral estrogen induces EBV lytic protein ZEBRA expression from the gene expression level. We expect of the development of novel treatment modalities such as anti‐hormonal treatment.
Journal Article
Comparison of radiological characteristics between diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis: a multicenter study
by
Nagoshi, Narihito
,
Takahashi, Takuya
,
Katsumi, Keiichi
in
692/4023/1671/1811
,
692/698/1671/1811
,
692/699/1670/2766/1827
2023
To evaluate the radiological differences between diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) using whole spine computed tomography (CT), including the spine and sacroiliac joint (SIJ). The ossification and bridging of spinal ligament and fusion of the facet joint and SIJ were evaluated in 111 patients who were diagnosed with DISH and 27 patients with AS on the whole spine CT. The number of anterior bridging and shape of bridging (candle-wax-type/ smooth-type) were also evaluated. We further evaluated patients with DISH and AS by matching their age and sex. Complete SIJ fusion was more common in AS, whereas anterior and posterior bony bridging around SIJ was more common in DISH. However, 63% of patients with DISH had a partial or complete fusion. In spinal anterior bony bridging, the majority of patients with AS had the smooth-type, whereas those with DISH had the candle-wax-type. However, some of the patients with DISH (11%) had smooth-type. Intervertebral facet joint fusion is more common in AS. The number of anterior spinal bony bridging was greater in AS than in DISH, especially in the lumbar spine. These results are useful in differentiating DISH from AS and should therefore be considered when making a diagnosis.
Journal Article