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Search Results: 1 - 10 of 1423 matches for " Michio Fujita "
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Aberrantly Glycosylated IgA1 as a Factor in the Pathogenesis of IgA Nephropathy
Mototsugu Tanaka,George Seki,Tomonosuke Someya,Michio Nagata,Toshiro Fujita
Clinical and Developmental Immunology , 2011, DOI: 10.1155/2011/470803
Abstract: Predominant or codominant immunoglobulin (Ig) A deposition in the glomerular mesangium characterizes IgA nephropathy (IgAN). Accumulated glomerular IgA is limited to the IgA1 subclass and usually galactose-deficient. This underglycosylated IgA may play an important role in the pathogenesis of IgAN. Recently, antibodies against galactose-deficient IgA1 were found to be well associated with the development of IgAN. Several therapeutic strategies based on corticosteroids or other immunosuppressive agents have been shown to at least partially suppress the progression of IgAN. On the other hand, several case reports of kidney transplantation or acquired IgA deficiency uncovered a remarkable ability of human kidney to remove mesangial IgA deposition, resulting in the long-term stabilization of kidney function. Continuous exposure to circulating immune complexes containing aberrantly glycosylated IgA1 and sequential immune response seems to be essential in the disease progression of IgAN. Removal of mesangial IgA deposition may be a challenging, but fundamental approach in the treatment of IgAN.
Effects of bistheonellide A, an Actin-polymerization Inhibitor, on Chinese Hamster V79 Cells and on IL-8 Production in PMA-stimulated HL-60 Cells
Taiko Oda,Jinzhong Xu,Ayako Fujita,Masataka Mochizuki,Michio Namikoshi
Marine Drugs , 2006, DOI: 10.3390/md401022
Abstract: Bioassay-guided isolation from the ethanol extract of a marine sponge Theonella sp. collected in Palau yielded bistheonellide A, which strongly inhibited the colony formation of Chinese hamster V79 cells (EC50 = 6.8 nM). Bistheonellide A is an actinpolymerization inhibitor and was suggested to control cytokine production. Therefore, we attempted to detect an effect of this compound on IL-8 production in PMA-stimulated HL- 60 cells. Interestingly, bistheonellide A did not modulate the production of IL-8 under cytotoxic concentrations as determined by LDH analysis. Although the correlation between the inhibition of microtubule assembly and the stimulation of IL-8 production has been observed for several compounds, the polymerization of actin was not related to an IL-8 production in the case of bistheonellide A. It will be suggested that the actin polymerization is not involved in the IL-8 production system.
Aberrantly Glycosylated IgA1 as a Factor in the Pathogenesis of IgA Nephropathy
Mototsugu Tanaka,George Seki,Tomonosuke Someya,Michio Nagata,Toshiro Fujita
Journal of Immunology Research , 2011, DOI: 10.1155/2011/470803
Abstract: Predominant or codominant immunoglobulin (Ig) A deposition in the glomerular mesangium characterizes IgA nephropathy (IgAN). Accumulated glomerular IgA is limited to the IgA1 subclass and usually galactose-deficient. This underglycosylated IgA may play an important role in the pathogenesis of IgAN. Recently, antibodies against galactose-deficient IgA1 were found to be well associated with the development of IgAN. Several therapeutic strategies based on corticosteroids or other immunosuppressive agents have been shown to at least partially suppress the progression of IgAN. On the other hand, several case reports of kidney transplantation or acquired IgA deficiency uncovered a remarkable ability of human kidney to remove mesangial IgA deposition, resulting in the long-term stabilization of kidney function. Continuous exposure to circulating immune complexes containing aberrantly glycosylated IgA1 and sequential immune response seems to be essential in the disease progression of IgAN. Removal of mesangial IgA deposition may be a challenging, but fundamental approach in the treatment of IgAN. 1. Introduction Since IgA nephropathy (IgAN) was firstly described by Berger and Hinglais in 1968 [1], IgAN is regarded one of the most common forms of glomerulonephritis worldwide [2]. Because 30 to 40% of IgAN patients reach end-stage kidney disease within 20 years [2, 3], it is critical to clarify the true pathogenesis. Clinical onset of IgAN is probably more common in the second and third decades of life [4–7]. This disease is more common in men, but reported male-female ratios were ranging from less than 2?:?1 in Japan to as high as 6?:?1 in the United States and northern Europe. Although IgAN occurs in all ethnic groups, the reason why whites and Asians are more prone to IgAN than are blacks remains unclear [8, 9]. Approximately 50% of newly diagnosed glomerulonephritis in Japan is due to IgAN, though much lower rates are reported in the United States and Western Europe [3]. Although there seems to be true racial differences due to a genetic predisposition to IgAN, the differences in kidney biopsy practices may also reflect these disparities [10]. IgAN is characterized by predominant or codominant IgA deposits in the glomerular mesangium, but many other diseases including Henoch-Sch?nlein purpura nephritis (HSPN) are also associated with glomerular IgA deposits [10]. Now, IgAN and HSPN are recognized to be related diseases since both can be encountered consecutively in the same patient, are found in identical twins, and bear identical pathological and biological
The Role of Adrenomedullin in the Renal NADPH Oxidase and (Pro)renin in Diabetic Mice
Michio Hayashi,Akihiro Tojo,Tatsuo Shimosawa,Toshiro Fujita
Journal of Diabetes Research , 2013, DOI: 10.1155/2013/134395
Abstract: Adrenomedullin has an antioxidative action and protects organs in various diseases. To clarify the role of adrenomedullin in diabetic nephropathy, we investigated the NADPH oxidase expression, renin-secreting granular cell (GC) hyperplasia, and glomerular matrix expansion in the streptozotocin (STZ)-induced diabetic adrenomedullin gene knockout (AMKO) mice compared with the STZ-diabetic wild mice at 10 weeks. The NADPH oxidase p47phox expression and lipid peroxidation products were enhanced in the glomeruli of the diabetic mice compared with that observed in the controls in both wild and AMKO mice. These changes were more obvious in the AMKO mice than in the wild mice. Glomerular mesangial matrix expansion was more severe in the diabetic AMKO mice than in the diabetic wild mice and exhibited a positive correlation with the degree of lipid peroxidation products in the glomeruli. Proteinuria was significantly higher in the diabetic AMKO mice than in the diabetic wild mice. The GC hyperplasia score and the renal prorenin expression were significantly increased in the diabetic AMKO mice than in the diabetic wild mice, and a positive correlation was observed with the NADPH oxidase expression in the macula densa. The endogenous adrenomedullin gene exhibits an antioxidant action via the inhibition of NADPH oxidase probably by suppressing the local renin-angiotensin system. 1. Introduction Adrenomedullin is a potent vasodilating peptide that is upregulated in cardiovascular diseases to counteract the disease process with its diverse physiological actions including antioxidative stress actions [1–6]. The plasma concentration of adrenomedullin also increased in the diabetic patients, and hyperglycemia increases the production of adrenomedullin in the vasculature [7, 8]. The receptors for adrenomedullin are expressed in the kidneys, especially in the glomerulus and distal nephron, and the local action of adrenomedullin is increased in diabetic rats [9], thus suggesting that adrenomedullin may contribute to the dilatation of the glomerular capillary in the early phase of diabetic nephropathy. Although the organoprotective effects of adrenomedullin have been demonstrated in various cardiovascular diseases, the mechanisms underlying its renoprotection in diabetic nephropathy are still unclear. Hyperglycemia accelerates the formation of advanced glycation end products (AGE), while also upregulating the protein kinase C (PKC) activity, accelerating the polyol pathway, and promoting sorbitol deposition [10]. These pathways are related to the increased oxidative stress,
Lippmann-Schwinger Resonating-Group Formalism for NN and YN Interactions in an SU6 Quark Model
Yoshikazu Fujiwara,Michio Kohno,Tadashi Fujita,Choki Nakamoto,Yasuyuki Suzuki
Physics , 1999, DOI: 10.1143/PTP.103.755
Abstract: We formulate a Lippmann-Schwinger-type resonating-group equation to calculate invariant amplitudes of the quark-model baryon-baryon interaction. When applied to our recent SU6 quark model for the nucleon-nucleon and hyperon-nucleon interactions, this technique yields very accurate phase-shift parameters for all partial waves up to the energies of several GeV. The technique also has a merit of a straightforward extension to the G-matrix equation. A new analytic method is proposed to calculate the quark-exchange Born kernel for the momentum-dependent two-body interaction. The partial-wave decomposition in the momentum representation is carried out numerically. The invariant amplitudes are then used to calculate single-nucleon potentials in normal nuclear matter for high incident momenta q_1 > 3 (1/fm), in which the so-called t^eff-rho prescription is found to be a good approximation to the single-particle potentials directly calculated in the lowest-order Brueckner theory.
Effects of Melophlins on Colony Formation of Chinese Hamster V79 Cells and IL-8 Production in PMA-stimulated HL-60 Cells
Taiko Oda,Ayako Fujita,Jinzhong Xu,Masataka Mochizuki,Kazuyo Ukai,Michio Namikoshi
Marine Drugs , 2007, DOI: 10.3390/md501001
Abstract: We have recently isolated four new melophlins P (1), Q (2), R (3), and S (4) together with seven known melophlins A (5), D (6), E (7), G (8), H (9), I (10), and O (11) from two marine sponges of the genus Melophlus collected in Palau. In this study, the influence of these compounds on the colony formation of Chinese hamster V79 cells and the production of IL-8 in PMA-stimulated HL-60 cells were examined. These 11 compounds did not show any effect on IL-8 production. The EC50 values of compounds 2, 3, 4, 5, 7, 9, 10, and 11 against V79 cells were 44.0, 13.3, 16.7, 27.2, 19.8, 8.5, 23.1, and 9.6 μM, respectively. The linear-chain-type compounds (1, 6, and 8) were not active against V79 cells at 50 μM. Although the growth inhibitory activity of these melophlins was not remarkable, some structure-activity relationships of these compounds against V79 and murine leukemia L1210 cells were observed.
Magnetic Resonance Findings of the Corpus Callosum in Canine and Feline Lysosomal Storage Diseases
Daisuke Hasegawa, Shinji Tamura, Yuya Nakamoto, Naoaki Matsuki, Kimimasa Takahashi, Michio Fujita, Kazuyuki Uchida, Osamu Yamato
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0083455
Abstract: Several reports have described magnetic resonance (MR) findings in canine and feline lysosomal storage diseases such as gangliosidoses and neuronal ceroid lipofuscinosis. Although most of those studies described the signal intensities of white matter in the cerebrum, findings of the corpus callosum were not described in detail. A retrospective study was conducted on MR findings of the corpus callosum as well as the rostral commissure and the fornix in 18 cases of canine and feline lysosomal storage diseases. This included 6 Shiba Inu dogs and 2 domestic shorthair cats with GM1 gangliosidosis; 2 domestic shorthair cats, 2 familial toy poodles, and a golden retriever with GM2 gangliosidosis; and 2 border collies and 3 chihuahuas with neuronal ceroid lipofuscinoses, to determine whether changes of the corpus callosum is an imaging indicator of those diseases. The corpus callosum and the rostral commissure were difficult to recognize in all cases of juvenile-onset gangliosidoses (GM1 gangliosidosis in Shiba Inu dogs and domestic shorthair cats and GM2 gangliosidosis in domestic shorthair cats) and GM2 gangliosidosis in toy poodles with late juvenile-onset. In contrast, the corpus callosum and the rostral commissure were confirmed in cases of GM2 gangliosidosis in a golden retriever and canine neuronal ceroid lipofuscinoses with late juvenile- to early adult-onset, but were extremely thin. Abnormal findings of the corpus callosum on midline sagittal images may be a useful imaging indicator for suspecting lysosomal storage diseases, especially hypoplasia (underdevelopment) of the corpus callosum in juvenile-onset gangliosidoses.
Geographic Variation in Germination Traits in Melia azedarach and Rhaphiolepis umbellata  [PDF]
Tetsuto Abe, Michio Matsunaga
American Journal of Plant Sciences (AJPS) , 2011, DOI: 10.4236/ajps.2011.21007
Abstract: Some plant species traits may not be uniform across populations distributed across a wide latitudinal range. This study examined intraspecies variation in the effects of cold stratification on the germination of seeds of two widespread trees, Rhaphiolepis umbellata (Rosaceae) and Melia azedarach (Meliaceae), collected from the subtropical Ogasawara Islands (southern seeds) and the temperate Japan mainland (northern seeds). Under the no-treatment control, the southern seeds germinated faster in R. umbellata and achieved a higher germination percentage in M. azedarach. The regional differences in germination performance were reduced by cold stratification. It was reasonable that these germination traits increase fitness under each climate region. Because the remote Ogasawara populations are sufficiently isolated to have developed some distinct characteristics, even common, widespread species may have important conservation value where they exist within insular biota.
Optimal Amount and Timing of Investment in a Stochastic Dynamic Cournot Competition  [PDF]
Yasunori Fujita
Theoretical Economics Letters (TEL) , 2016, DOI: 10.4236/tel.2016.61001
Abstract: By making use of the optimal stopping theory, we construct a multi-stage stochastic Cournot model to examine the effect of increase in uncertainty and number of entrants on the amount and timing of strategic cost reduction investment. It is revealed that firms should enlarge and postpone the investment if 1) the market is more uncertain, or 2) there exist more firms in the market.
Piketty’s Capital-Income Theory Reconsidered for a Small Open Economy with Increasing Savings Rate  [PDF]
Yasunori Fujita
Open Journal of Statistics (OJS) , 2016, DOI: 10.4236/ojs.2016.61004
Abstract:

Since Piketty offered a new view of capital/income ratio, numerous attempts have been made to examine the relationship between return on capital, economic growth and the capital/income ratio. This paper attempts to shed new light on this field. More precisely, following recent literatures that pay attention to dynamics of external balance sheets of countries, we examine if Piketty’s results for large countries are robust for a country that takes the world rate of return on capital as given and whose savings rate increases gradually from negative value. It is revealed that for such a country, (1) Kuznets curve is drawn and (2) capital/income ratio decreases in accordance with a rise in savings rate and return on capital.

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