Publications by authors named "Wakamatsu K"

Sodium ozagrel (ozagrel), a selective thromboxane A2 synthetase inhibitor, has been used for the treatment of various types of acute ischemic stroke, except cardioembolic stroke. Recently, edaravone, a novel free radical scavenger, has been approved for the treatment of acute ischemic stroke within 24 hours after onset. Since these two drugs differ in mode of action, we hypothesized that combination of both drugs would yield further improvement of the outcome of patients with acute ischemic stroke.

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The biosynthesis, structure and function of neuromelanin (NM), the dark brown melanin-like pigment present in the substantia nigra (SN), are not well characterized, in spite of the possible involvement of NM in the etiology and pathogenesis of Parkinson's disease. NM was isolated from the SN of five non-Parkinsonian human brains. NM and synthetic melanins, employed as models, were characterized by chemical analysis.

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5-S-Cysteinyldopa (5-S-CD) has been used as a biochemical marker of melanoma progression. Recently we have shown that the serum level of 5-S-CD is a sensitive and specific marker in predicting distant metastases. In melanocytes and melanoma cells, cysteinyldopa isomers are oxidized to phaeomelanin, the yellow to reddish melanin pigment.

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Eumelanin was isolated from a sample of black, Indonesian human hair using three different published procedures: two different acid/base extractions and an enzymatic extraction. The morphology and spectroscopic properties of the isolated pigments differ significantly. The acid/base procedures both yield an amorphous material, while enzymatic extraction yields ellipsoidal melanosomes.

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Ultrastructural examination of renal biopsy specimens is often necessary to establish a diagnosis. We have noted, in some renal biopsies, that normal-appearing glomerular basement membrane (GBM) shows an electron densification. The aim of this study was to describe this phenomenon and assess the degree of its occurrence.

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DNA damage induced by UV radiation is a critical event in skin photocarcinogenesis. However, the role of racial/ethnic origin in determining individual UV sensitivity remains unclear. In this study, we examined the relationships between melanin content and DNA damage induced by UV exposure in situ in normal human skin of different racial/ethnic groups, phototypes, and UV sensitivities.

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A monotypic angiomyolipoma of the nasal cavity in a 34-year-old woman is described. Tumor cells were spindled or epithelioid and contained glycogen and diastase-resistant PAS-positive granules. There were few mitoses, and necrosis was absent, indicating a benign tumor.

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Melanin pigments produced in human melanocytes are classified into two categories; black coloured eumelanin and reddish-yellow pheomelanin. Stimulation of melanocytes with alpha-melanocyte-stimulating hormone (alpha-MSH), one of several melanogenic factors, has been reported to enhance eumelanogenesis to a greater degree than pheomelanogenesis, which contributes to hyperpigmentation in skin. Nitric oxide (NO) and histamine are also melanogenesis-stimulating factors that are released from cells surrounding melanocytes following ultraviolet (UV) irradiation.

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Activation of the superoxide-producing phagocyte NADPH oxidase, crucial in host defense, requires the cytosolic proteins p67(phox) and p47(phox). They translocate to the membrane upon cell stimulation and activate flavocytochrome b(558), the membrane-integrated catalytic core of this enzyme system. The activators p67(phox) and p47(phox) form a ternary complex together with p40(phox), an adaptor protein with unknown function, comprising the PX/PB2, SH3 and PC motif- containing domains: p40(phox) associates with p67(phox) via binding of the p40(phox) PC motif to the p67(phox) PB1 domain, while p47(phox) directly interacts with p67(phox) but not with p40(phox).

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Metabolism of glutathione by gamma-glutamyl transpeptidase (gamma-GT) at the level of cell membrane has been shown to generate hydrogen peroxide in many cell types including human melanomas. gamma-GT does not appear to be involved in cysteine uptake for pheomelanin production in melanoma cells and does not contribute significantly to the pheomelanin synthesized in B16 melanoma cells. We have therefore examined the possibility of gamma-GT mediated production of prooxidant reactions and its effect, if any, on pigmentation using B16 melanoma cells.

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A case of penis construction using two free flaps is presented. The urethra is constructed with an ulnar forearm flap and external coverage is provided with deltoid flap. The biggest disadvantage with radial forearm flap, which is considered to be the most ideal donor flap for penile construction, is its large and unsightly donor scar.

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One of the principal applications of tumour markers is the early detection of recurrent disease in the follow-up of patients. In the study described here, we compared the usefulness of two serum markers for melanoma, 5-S-cysteinyldopa (5-S-CD) and melanoma inhibitory activity (MIA), in the monitoring of postsurgical melanoma patients. A total of 154 serum samples taken from 45 melanoma patients, who underwent surgery of the primary tumour and were under periodical follow-up for 13 to 180 months, were analysed.

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Transglutaminases catalyze the cross-linking and amine incorporation of proteins, and are implicated in various biological phenomena. Previously, we found a high molecular mass transglutaminase-inhibitory substance produced by Streptomyces lavendulae Y-200 that appeared to be a melanin substance. Here, we report that synthetic tyrosine melanin inhibited various types of transglutaminases.

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5-S-Cysteinyldopa (5-S-CD) has been used as a biochemical marker of melanoma progression. In this study, we measured serum levels of 5-S-CD in 2648 samples taken from 218 patients in order to evaluate the usefulness of this parameter in following melanoma progression and prognosis. 5-S-CD levels were significantly elevated above the upper limit of the normal range (10 nmol/l) in stage IV melanoma patients.

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Magainin 2 from African clawed frog Xenopus laevis is an antimicrobial peptide with broad spectra and action mechanisms considered to permeabilize bacterial membranes. CD, vibration, and solid-state NMR spectroscopies indicate the peptide adopts an alpha-helical conformation on binding to phospholipid bilayers, and its micelle-bound conformation, being monomeric and alpha-helical, is well detailed. We showed, however, that the peptide dimerizes on binding to phospholipid bilayers.

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The epidermal cell suspensions of the neonatal dorsal skin derived from wild type mouse at the pink-eyed dilution (p) locus (black, C57BL/10JHir-P/P) and their congenic mutant mouse (pink-eyed dilution, C57BL/10JHir-p/p) were cultured with a serum-free melanocyte growth medium supplemented with additional L-tyrosine (Tyr) from initiation of the primary culture. L-Tyr inhibited the proliferation of P/Pmelanocytes in a dose-dependent manner, whereas L-Tyr stimulated the proliferation of p/p melanoblasts and melanocytes regardless of dose. On the other hand, L-Tyr stimulated (P/P) or induced (p/p) the differentiation of epidermal melanocytes in a dose-dependent manner.

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Reductive hydrolysis of pheomelanin with hydriodic acid (HI) gives two aminohydroxyphenylalanine isomers, 4-amino-3-hydroxyphenylalanine ('specific AHP') and 3-amino-4-hydroxyphenylalanine (3-aminotyrosine, AT), which derive from the oxidative polymerization of 5-S-cysteinyldopa, and 2-S-cysteinyldopa, respectively. Since we first introduced this analytical method, the combined amount of AHP and AT ('total AHP') has been extensively used as a marker of pheomelanin. However, one problem with using total AHP as a marker is that background levels originate from precursors other than pheomelanin.

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Among the biopolymers, melanins are unique in many respects. The other essential biopolymers - proteins, nucleic acids, and carbohydrates - are chemically well characterized; their precursors (monomer units) and modes of connection between the monomer units are known, and sequences of their connection can be determined with well-established methodologies. In contrast, we still do not have a method to determine accurately the ratio of various units present in melanins.

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Cutaneous pigmentation is determined by the amounts of eumelanin and pheomelanin synthesized by epidermal melanocytes and is known to protect against sun-induced DNA damage. The synthesis of eumelanin is stimulated by the binding of alpha-melanotropin (alpha-melanocyte-stimulating hormone) to the functional melanocortin 1 receptor (MC1R) expressed on melanocytes. The human MC1R gene is highly polymorphic and certain allelic variants of the gene are associated with red hair phenotype, melanoma and non-melanoma skin cancer.

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Agouti is a paracrine-acting, transient antagonist of melanocortin 1 receptors that specifies the subapical band of yellow on otherwise black hairs of the wild-type coat. To better understand both agouti structure/function and the germline damage caused by chemicals and radiation, an allelic series of 25 recessive, homozygous-viable agouti mutations generated in specific-locus tests were characterized. Visual inspection of fur, augmented by quantifiable chemical analysis of hair melanins, suggested four phenotypic categories (mild, moderate, umbrous-like, severe) for the 18 hypomorphs and a single category for the 7 amorphs (null).

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Cells positive to the dopa reaction (melanocytes) as well as to the combined dopa-premelanin reaction (melanoblasts and melanocytes) in the epidermis of C57BL/10JHir-p/p (pink-eyed dilution) mice were fewer and less reactive than in C57BL/10JHir (black, P/P) mice, suggesting that the proliferation and differentiation of p/p melanocytes are inhibited. To confirm the inhibitory effects of p gene on the proliferation and differentiation of epidermal melanocytes, we cultured epidermal cell suspensions of neonatal skins from P/P and p/p in a serum-free medium. The proliferation and differentiation of p/p melanoblasts/melanocytes in primary culture were greatly inhibited as compared to P/P melanoblasts/melanocytes.

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Although the heart rate variability (HRV) values in adults decrease with aging, those in children show a variety of changes. The present study was designed to investigate the relationship between HRV and aging, physique and blood pressure in 70 healthy male school children, between 6 and 12 years of age. The subjects were divided into 3 age groups (6-7, 8-9 and 10-12 years) and 3 other groups according to physique (thin, under -10%; normal, -10-20% and obese, over 20% of obesity index).

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The network of elastic system fibers in human fibrotic liver was investigated by histological methods, immunohistochemical staining, and electron microscopy. Type III collagen was seen not only in regions of portal fibrosis but also in the sinusoidal wall. However, elastic system fibers were not found in the Disse space of the sinusoidal wall.

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The epidermal melanin unit in human skin is composed of melanocytes and keratinocytes. Melanocytes, located in the basal layer of the epidermis, manufacture melanin-loaded organelles called melanosomes. Through their dendritic processes, melanocytes distribute melanosomes to neighboring keratinocytes, where their presence confers to the skin its characteristic color and photoprotective properties.

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