Publications by authors named "Masayoshi Tachibana"

A full-custom design of chaos-based True Random-Bit Generator (TRBG) implemented on a 0.18-μm CMOS technology is presented with unique composition of three major components, i.e.

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The search for generation approaches to robust chaos has received considerable attention due to potential applications in cryptography or secure communications. This paper is of interest regarding a 1-D sigmoidal chaotic map, which has never been distinctly investigated. This paper introduces a generic form of the sigmoidal chaotic map with three terms, i.

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Mammalian pigment cells produce melanin as the main pigment. Melanocytes, one of the two types of mammalian pigment cells, differentiate from the neural crest and migrate to a variety of organs during development. Melanocytes exist not only in the skin but also in other sites such as the cochlea where they are essential for hearing.

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The WS4 mouse is an animal model for human Waardenburg syndrome type 4 (WS4), showing pigmentation anomalies, deafness and megacolon, which are caused by defects of neural crest-derived cells. We have previously reported that the gene responsible for the WS4 mouse is an allele of the piebald mutations of the endothelin B receptor gene (Ednrb). In this study, we examined the genomic sequence of the Ednrb gene in WS4 mice and found a 598-bp deletion in the gene.

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Increasing exposure to environmental endocrine disruptor, xeno-estrogen, is a serious hazard to male reproductive activity. To explore possible genetic control in susceptibility to xeno-estrogen, the weight reduction of testes induced by the continuous administration of a synthetic estrogen, diethylstilbesterol, were investigated by quantitative trait analysis in LEXF and FXLE recombinant inbred strain rats, consisting of 21 independent strains, 9 of their substrains, parental F344/Stm and LE/Stm strains, and (F344 x LE)F1. For the weight of testes, one highly significant quantitative trait locus (QTL) and one significant QTL were mapped on chromosomes 7 and 1, respectively.

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Angiogenesis is induced by various angiogenic factors including vascular endothelial growth factors (VEGFs), such as VEGF-A, -B, -C and -D, and is involved in tumor progression and metastasis. In an effort to define the expression pattern of VEGFs in oral squamous cell carcinoma (OSCC) and its correlation with clinicopathological factors, we determined the expression levels of VEGFs in OSCC cell lines (HSC-2, HSC-3, HSC-4 and OSC-19) by quantitative RT-PCR and examined their relationship with regional lymph node (LN) and distant metastasis, intratumoral microvessel density (MVD) in tumor transplanted nude mice. We found that HSC-2 and OSC-19 expressed significantly higher levels of VEGF-A and VEGF-C, and caused frequent regional LN metastasis and higher MVD than did the other cell lines.

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Gene science-based diagnoses have become an increasingly realistic option as the state of knowledge has improved regarding the genetic basis of disease. To facilitate the creation of this potential diagnostic tool, researchers have made large-scale detection of point mutations a key issue. Here, we propose an inexpensive and convenient method with a high performance level for this purpose: micro temperature gradient gel electrophoresis (muTGGE)-empowered heteroduplex analysis (muTG-HD).

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Infantile neuroaxonal dystrophy (INAD) is a rare autosomal recessive hereditary neurodegenerative disease of humans. So far, no responsible gene has been cloned or mapped to any chromosome. For chromosome mapping and positional cloning of the responsible gene, establishment of an animal model would be useful.

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To clarify the correlation of genomic alterations with clinical and histological features, we performed metaphase comparative genomic hybridization analysis on 20 primary cutaneous melanomas, which were obtained by laser capture or manual microdissection, and 16 melanoma cell lines. There were no differences in the average number of aberrations between acral melanomas (AM) and non-AM, although gains of 5q and 11q13 were more frequent (P=0.05) and 10q loss was less frequent (P=0.

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N-3 fatty acids exert a potent serum lipid-lowering effect in rodents mainly by affecting hepatic fatty acid oxidation and synthesis. However, it has been observed that fish oil and docosahexaenoic acid ethyl ester do not lower serum lipid levels in apolipoprotein E (apoE)-knockout (Apoetm1Unc) mice generated by gene targeting. To test the hypothesis that apoE expression is required for n-3 fatty acid-dependent regulation of serum lipid levels and hepatic fatty acid metabolism, we examined the effect of fish oil and n-3 fatty acid ethyl esters on the activity and gene expression of hepatic enzymes involved in fatty acid oxidation and synthesis using an alternative apoE-deficient mouse model with the BALB/c genetic background (BALB/c.

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In an effort to find proteins overexpressed in metastatic colonic adenocarcinomas, differential proteome analyses were undertaken using primary and metastatic tumors. Two-dimensional-gel profiles showed a number of spots that appeared in metastatic tumor in liver, but not in primary tumor. Amino acid or mass spectrometric analyses of some of these spots revealed tht they were apolipoprotein A1 (Apo A1), a protein that is normally expressed in liver and small intestine.

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Waardenburg syndrome (WS) is an auditory-pigmentary syndrome caused by a deficiency of melanocytes and other neural crest-derived cells. Depending on a variety of symptoms associated with the auditory-pigmentary symptoms, WS is classified into four types: WS type 1 (WS1), WS2, WS3, and WS4. Six genes contributing to this syndrome--PAX3, SOX10, MITF, SLUG, EDN3 and EDNRB--have been cloned so far, all of them necessary for normal development of melanocytes.

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Purpose: Mouse corneas were investigated to see whether a limbal annulus of corneal collagen exists as in humans. Mice with corneas predisposed to topographical changes (the SKC strain) were also examined, to establish the size and spacing of stromal collagen fibrils and the integrity of the annulus.

Methods: X-ray diffraction was used to measure collagen fibril spacing and diameter in normal (the BALB/c strain; four male, two female) and SKC (six male and six female) corneas and to identify the degree of preferred collagen orientation at 200- microm intervals across two BALB/c and four SKC corneas.

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1. The effects of two naturally occurring substances, namely taurine and catechins, on serum cholesterol levels and on the progression of atherosclerotic lesions were evaluated using spontaneously hyperlipidaemic (SHL) mice as an animal model of atherogenesis. 2.

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Dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome, gene 1 (Dax-1, NR0B1) is an orphan nuclear receptor that represses transcription by Ad4 binding protein/steroidogenic factor 1 (Ad4BP/SF-1, NR5A1). Observations on human diseases and the phenotypes of mice, in which the corresponding genes have been disrupted, have elucidated essential roles of these two nuclear receptors in differentiation of steroidogenic tissues. However, little is known about how the functions of these factors are regulated.

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Human keratoconus is a common corneal disease with non-inflammatory corneal ectasia, and a subset of this disease is heritable. In an effort to establish animal models for this disease, we discovered Japanese keratoconus (JKC) mice among Mishima molosinus (MSM) mice, an inbred strain of Japanese wild mice (Mus musculus molossinus). Typical phenotypic corneas of JKC mice are, like human keratoconus, conical in shape, although the corneas were often associated with a red punctum at the tip.

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Waardenburg syndrome (WS) is characterized by deafness and hypopigmentation because of the lack of melanocytes in the inner ear and skin. WS type 2 is associated with mutations in the gene encoding microphthalmia-associated transcription factor (MITF) that is required for melanocyte differentiation. MITF consists of multiple isoforms with different N-termini, one of which is exclusively expressed in melanocytes, named MITF-M.

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Waardenburg syndrome (WS) is a hereditary auditory-pigmentary syndrome with hearing impairment and pigmentation anomaly of the skin and iris. In addition to these major symptoms, WS type 4 is associated with Hirschsprung disease. To date, three genes responsible for WS4 have been cloned: genes for a transcription factor SOX10, endothelin 3 (EDN3), and endothelin B receptor (EDNRB).

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Purpose: To better understand the pathogenesis of hereditary keratoconus, an inbred line of spontaneous mutant mice with keratoconus-affected corneas (SKC mice) was established and studied with a multidisciplinary approach.

Methods: Using a mutant mouse with corneas having a keratoconical appearance as the progenitor, an inbred line of SKC mouse was established by repeated sibling mating. Morphology, cell growth, apoptosis and protein expression of SKC mouse corneas were examined.

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