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Biomedical subjects

Y Furukawa

Publications and source records attributed to Y Furukawa.

At least 19 recordsLinked to original sources
PubMed2006

Fulde-Ferrell-Larkin-Ovchinnikov state in a perpendicular field of quasi-two-dimensional CeCoIn5.

A Fulde-Ferrell-Larkin-Ovchinnkov (FFLO) state was previously reported in the quasi-2D heavy fermion CeCoIn5 when a magnetic field was applied parallel to the ab plane. Here, we conduct 115In NMR studies of this material in a perpendicular field, and provide strong evidence for FFLO in this case as well. Although the topology of the phase transition lines in the H-T phase diagram is identical for both configurations, there are several remarkable differences between them. Compared to H parallelab, the FFLO phase for H perpendicularab is confined in a much narrower region at the low-T-high-H corner in the H-T plane, and the critical field separating the FFLO and non-FFLO superconducting states almost ceases to have a temperature dependence. Moreover, directing H perpendicularab results in a notable change in the quasiparticle excitation spectrum within the planar node associated with the FFLO transition.

Journal Article↗
PubMed2006

Three catheter-based strategies for cardiac delivery of therapeutic gelatin microspheres.

Gelatin hydrogel microspheres (GHMs) have been reported as novel non-viral vectors for gene or protein delivery (GHM therapy). However, the components of an effective catheter-based delivery strategy for GHM therapy are unknown. We evaluated the effectiveness of three catheter-based strategies for cardiac GHM therapy: (1) antegrade injection (AI) via coronary arteries; (2) retrograde injection (RI) via coronary veins; and (3) direct myocardial injection (DI) via the coronary sinus. AI distributed microspheres homogeneously throughout the target area with 73+/-11% retention. RI scattered microspheres non-homogenously with 22+/-8% retention. DI distributed microspheres in the needle-advanced area with 47+/-14% retention. However, despite high efficiency, AI did not show biological effects of inducing angiogenesis from basic fibroblast growth factor bound to GHMs. Furthermore, focal micro-infarctions, owing to micro-embolism of aggregated GHMs into small coronary arterioles, were detected in the AI group. Conversely, only RI and DI groups displayed increased coronary flow reserve. DI groups also demonstrated increased capillary density. These results suggest that RI and DI are effective for cardiac GHM therapy, while AI appears inappropriate owing to the risk of focal infarctions.

Animals↗
PubMed2006

TIPUH1 encodes a novel KRAB zinc-finger protein highly expressed in human hepatocellular carcinomas.

To achieve a better understanding of mechanisms that underlie hepatocarcinogenesis and to identify novel target molecules for diagnosis and therapy of hepatocellular carcinoma (HCC), we previously analysed gene-expression profiles of 20 HCC tissues on a cDNA microarray. Among the genes upregulated in the tumor tissues compared with their nontumor counterparts, we focused on a novel gene termed transcription-involved protein upregulated in HCC (TIPUH1) that putatively encoded a 500-amino-acid protein containing 12 zinc-finger domains and a Kruppel-associated box domain. Multiple-tissue northern blot analysis revealed it's testis- and placenta-specific expression in normal tissues. Colony-formation assay in soft agar showed that TIPUH1 conferred anchorage-independent growth to NIH3T3 cells, suggesting its oncogenic activity. Conversely, specific siRNA for TIPUH1 knocked down its expression in HCC cells, which resulted in their growth inhibition. We identified four TIPUH1-interacting proteins including TIF1beta, a transcription-intermediary protein, and three involved in pre-mRNA processing (hnRNPU, hnRNPF, and Nucleolin), suggesting that overexpressed TIPUH1 may play a role in hepatocarcinogenesis by regulating transcription and/or RNA processing of growth control genes. These data may contribute to a better understanding of liver neoplasia, and to the development of novel strategy for treatment of HCCs.

Animals↗
PubMed2006

Histone deacetylase inhibitor FK228 suppresses the Ras-MAP kinase signaling pathway by upregulating Rap1 and induces apoptosis in malignant melanoma.

Histone deacetylase (HDAC) inhibitors are expected to be effective for refractory cancer because their mechanism of action differs from that of conventional antineoplastic agents. In this study, we examined the effect of the HDAC inhibitor FK228 on malignant melanoma, as well as its molecular mechanisms. FK228 was highly effective against melanoma compared with other commonly used drugs. By comparing the gene expression profiles of melanoma cells and normal melanocytes, we defined a subset of genes specifically upregulated in melanoma cells by FK228, which included Rap1, a small GTP-binding protein of the Ras family. The expression of Rap1 mRNA and protein increased in FK228-treated melanoma cells in both a dose- and a time-dependent manner. A decrease in the phosphorylation of c-Raf, MEK1/2, and ERK1/2 was accompanied by an increase in Rap1 expression in both FK228-treated and Rap1-overexpressing cells. Inhibition of Rap1 upregulation by small interfering RNA (siRNA) abrogated the induction of apoptosis and suppression of ERK1/2 phosphorylation in FK228-treated melanoma cells. These results indicate that the cytotoxic effects of FK228 are mediated via the upregulation of Rap1. Furthermore, we found that Rap1 was overexpressed and formed a complex with B-Raf in melanoma cell lines with a V599E mutation of B-Raf. The siRNA-mediated abrogation of Rap1 overexpression increased the viability of these cells, suggesting that Rap1 is also an endogenous regulator of Ras-MAP kinase signaling in melanomas.

Animals↗
PubMed2006

Elevated expression of C10orf3 (chromosome 10 open reading frame 3) is involved in the growth of human colon tumor.

After analysing gene-expression profiles of colon cancers on a cDNA microarray containing cDNAs corresponding to 23 040 human genes, we focused on a gene annotated as C10orf3 (chromosome 10 open reading frame 3), whose expression was elevated in colorectal cancers (CRC) as well as in tumors arising in the stomach, lung, pancreas, and breast. The gene encodes a putative 464-amino-acid protein containing a domain known as AAA (ATPases associated with a variety of cellular activities). Western blot analysis using an antibody to the gene product confirmed that the protein was overexpressed in nine of the 15 clinical cancer tissues examined, compared to corresponding noncancerous epithelial cells. A subsequent proteomics analysis revealed that C10orf3 product associated with the product of tumor susceptibility gene 101 (TSG101), and that C10orf3 downregulated TSG101 in a post-transcriptional manner. Expression of short interfering RNA in cells derived from CRC caused significant decreases in C10orf3 expression and inhibited growth of the transfected cells, which was associated with increased apoptotic cells. These data suggest that elevated C10orf3 expression might play an essential role in the growth of cancer cells, and that suppression of C10orf3-mediated signal transduction may be a novel therapeutic strategy to a wide range of human tumors.

Cell Division↗
PubMed2006

Background values for evaluation of heavy metal contamination in sediments.

The contamination of sediments can be evaluated from comparison of the current concentration with the estimated background value. Although it is known that grain size affects background concentrations, there have been difficulties in evaluating this effect. The specific surface area of sediments, which can be calculated from the grain size distribution, is introduced as a property index for correlation of background values. The results show that for sandy-to-sandy silt sediments, the background values of metals are expressed in terms of fines content, which can be correlated with the corresponding specific surface area. However, for silty clay or clayey silt sediments, which would have a high metal retention capacity, the level of the background may be constrained by the relatively low concentrations of metals in seawater. Finally, background levels of Zn, Cu and Pb are presented.

Adsorption↗
PubMed2006

Neuromyelitis optica associated with myasthenia gravis: characteristic phenotype in Japanese population.

We report two female patients with neuromyelitis optica (NMO, Devic's syndrome) following or coincidental with myasthenia gravis (MG). Their illnesses were characterized by subacute myelitis with optic neuritis, high serum levels of muscle acetylcholine receptor antibody, and autoimmune thyroid disease. Both patients fulfilled the clinical criteria of NMO, however, NMO-IgG, autoantibody against aquaporin-4 water channel, was absent from their sera. Both NMO and MG are relatively rare diseases. The considerable coincidence of these two disorders suggests that there is a subgroup of patients with NMO having a common immunological pathogenesis with MG.

Adult↗
PubMed2005

Novel excitatory neuropeptides isolated from a prosobranch gastropod, Thais clavigera: The molluscan counterpart of the annelidan GGNG peptides.

The GGNG peptides are excitatory neuropeptides identified from earthworms, leeches and polychaeta. Two structurally related peptides were purified and characterized from a mollusk, Thais clavigera (prosobranch gastropod). The peptides designated as Thais excitatory peptide-1 (TEP-1) (KCSGKWAIHACWGGN-NH2) and TEP-2 (KCYGKWAMHACWGGN-NH2) are pentadecapeptides having one disulfide bond and C-terminal GGN-NH2 structures, which are shared by most GGNG peptides. TEP augmented the motilities of Thais esophagus and penial complex. TEP-like immunoreactivity is distributed in both the neurons of the central nervous system and nerve endings in the penial complex. Thus, the involvement of TEP in the contraction of the digestive and reproductive systems is suggested. Substitution of amino acids in TEP revealed that two tryptophan residues in TEP are important for maintaining bioactivity.

Amino Acid Sequence↗
PubMed2005

Clinical diagnosis of MM2-type sporadic Creutzfeldt-Jakob disease.

BACKGROUND: No method for the clinical diagnosis of MM2-type sporadic Creutzfeldt-Jakob disease (sCJD) has been established except for pathologic examination. OBJECTIVE: To identify a reliable marker for the clinical diagnosis of MM2-type sCJD. METHODS: CSF, EEG, and neuroimaging studies were performed in eight patients with MM2-type sCJD confirmed by neuropathologic, genetic, and western blot analyses. RESULTS: The eight cases were pathologically classified into the cortical (n = 2), thalamic (n = 5), and combined (corticothalamic) (n = 1) forms. The cortical form was characterized by late-onset, slowly progressive dementia, cortical hyperintensity signals on diffusion-weighted imaging (DWI) of brain, and elevated levels of CSF 14-3-3 protein. The thalamic form showed various neurologic manifestations including dementia, ataxia, and pyramidal and extrapyramidal signs with onset at various ages and relatively long disease duration. Characteristic EEG and MRI abnormalities were almost absent. However, all four patients examined with cerebral blood flow (CBF) study using SPECT showed reduction of the CBF in the thalamus as well as the cerebral cortex. The combined form had features of both the cortical and the thalamic forms, showing cortical hyperintensity signals on DWI and hypometabolism of the thalamus on [18F]2-fluoro-2-deoxy-d-glucose PET. CONCLUSION: For the clinical diagnosis of MM2-type sporadic Creutzfeldt-Jakob disease, cortical hyperintensity signals on diffusion-weighted MRI are useful for the cortical form and thalamic hypoperfusion or hypometabolism on cerebral blood flow SPECT or [18F]2-fluoro-2-deoxy-d-glucose PET for the thalamic form.

14-3-3 Proteins↗
PubMed2004

Components and fractions for differently bound water molecules of dipalmitoylphosphatidylcholine-water system as studied by DSC and 2H-NMR spectroscopy.

Differently bound water molecules of dipalmitoylphosphatidylcholine (DPPC)-H2O system were investigated with differential scanning calorimetry (DSC). According to a method previously reported by us, the ice-melting DSC curves of the DPPC-H2O samples of varying water contents were deconvoluted into multiple components, and the ice-melting enthalpies for the individual deconvoluted components were used to estimate average molar ice-melting enthalpies for freezable interlamellar and bulk waters, respectively. With these average molar ice-melting enthalpies, the numbers of differently bound water molecules of the DPPC-H2O system were calculated at varying water contents and were used to construct a water distribution diagram of this system. Furthermore, to evaluate the reliability of the present DSC deconvolution method, 2H-NMR T1 measurements of DPPC-2H2O system were carried out at 5 degrees C of the gel phase temperature, and components and fractions for differently bound water (2H2O) molecules were estimated from the analysis of nonexponential magnetization recovery curves.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2004

Chronic progressive cervical myelopathy with HTLV-I infection: Variant form of HAM/TSP?

OBJECTIVE: To investigate the role of human T-lymphotrophic virus type I (HTLV-I) infection in four patients who developed slowly progressive myelopathy with abnormal MRI lesions in the cervical cord levels. METHODS: Clinical and neuroradiologic examinations were performed, and the odds that an HTLV-I-infected individual of specified genotype, age, and provirus load had HTLV-I-associated myelopathy (HAM)/tropical spastic paraparesis (TSP) were calculated. RESULTS: Anti-HTLV-I antibodies were positive in both the serum and the CSF in all of the patients. Biopsied sample from spinal cord lesions showed inflammatory changes in Patient 1. Patient 2 had a demyelinating type of sensorimotor polyneuropathy. Two of the three patients examined showed high risk of developing HAM/TSP in virologic and immunologic aspects. CONCLUSION: These four cases may belong to a variant form of HAM/TSP, predominantly involving the cervical cord levels.

Aged↗
PubMed2003

PRQFVamide, a novel pentapeptide identified from the CNS and gut of Aplysia.

We have purified a novel pentapeptide from the Aplysia nervous system using bioassay on gut contractions. The structure of the peptide is Pro-Arg-Gln-Phe-Val-amide (PRQFVa). The precursor for PRQFVa was found to code for 33 copies of PRQFVamide and four related pentapeptides. Peaks corresponding to the predicted masses of all five pentapeptides were detected in Aplysia neurons by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Northern analysis revealed that expression of the precursor is abundant in the abdominal ganglion, much less in the pedal and cerebral ganglia, and rarely seen in the buccal and pleural ganglia. PRQFVa-positive neurons, mapped by immunohistochemistry and in situ hybridization, were present in all the central ganglia. PRQFVa immunopositive processes were observed in the gut, particularly in association with the vasculature. Some arteries and other highly vascularized tissues, such as the gill and the kidney, also contain numerous PRQFVa immunopositive processes. Application of synthetic PRQFVa suppresses not only contractions of the gut but also contractions of vasculature. PRQFVa is expressed in some of the neurons within the feeding circuitry and application of synthetic PRQFVa was found to decrease the excitability of some (B4/5 and B31/32) but not all (B8) neurons of the buccal feeding circuit. Our findings suggest that PRQFVa may act as a modulator within the feeding system as well as in other systems of Aplysia.

Amides↗
PubMed2003

Sporadic Creutzfeldt-Jakob disease with MM1-type prion protein and plaques.

The authors report a 75-year-old woman with atypical sporadic Creutzfeldt-Jakob disease (CJD) characterized by MM1-type prion protein (PrP) (methionine homozygosity at codon 129 in the PrP gene and type-1 protease-resistant PrP) and PrP plaques. This patient is the first case of sporadic CJD with plaque-forming MM1-type PrP, suggesting either a shared prion strain with the plaque-forming subset of dural graft-associated CJD or shared host genetic factors that are unrelated to the PrP genotype.

Aged↗
PubMed2003

Distribution and function of an Aplysia cardioexcitatory peptide, NdWFamide, in pulmonate snails.

The distribution and function of an Aplysia cardioexcitatory peptide, NdWFamide, were examined in the nervous system of pulmonate snails. We chemically identified the authentic NdWFamide from a land snail (Euhadra congenita) and a freshwater snail (Lymnaea stagnalis). NdWFamide potentiated the heartbeat of those snails. Immunohistochemistry using anti-NdWFamide antibody demonstrated the distribution of NdWFamide-containing neurons and fibers in the central nervous system, as well as peripheral tissues, such as the cardiovascular region and accessory sex organs. These results suggest that NdWFamide is a neuropeptide mediating the neural regulation of the activity of the cardiovascular and reproductive systems of snails.

Animals↗
PubMed2003

Seasonal changes of CO(2), CH(4) and N(2)O fluxes in relation to land-use change in tropical peatlands located in coastal area of South Kalimantan.

Tropical peatland could be a source of greenhouse gases emission because it contains large amounts of soil carbon and nitrogen. However these emissions are strongly influenced by soil moisture conditions. Tropical climate is characterized typically by wet and dry seasons. Seasonal changes in the emission of carbon dioxide (CO(2)), methane (CH(4)) and nitrous oxide (N(2)O) were investigated over a year at three sites (secondary forest, paddy field and upland field) in the tropical peatland in South Kalimantan, Indonesia. The amount of these gases emitted from the fields varied widely according to the seasonal pattern of precipitation, especially methane emission rates were positively correlated with precipitation. Converting from secondary forest peatland to paddy field tended to increase annual emissions of CO(2) and CH(4) to the atmosphere (from 1.2 to 1.5 kg CO(2)-C m(-2)y(-1) and from 1.2 to 1.9 g CH(4)-C m(-2)y(-1)), while changing land-use from secondary forest to upland tended to decrease these gases emissions (from 1.2 to 1.0 kg CO(2)-C m(-2)y(-1) and from 1.2 to 0.6 g CH(4)-C m(-2)y(-1)), but no clear trend was observed for N(2)O which kept negative value as annual rates at three sites.

Carbon Dioxide↗
PubMed2003

Identification of a vasopressin-like immunoreactive substance in hydra.

Vasopressin (VP)-like immunoreactivity has long been known in the hydra nervous system, but has not yet been structurally identified. In this study, using HPLC fractionation and an immunological assay, we have purified two peptides, FPQSFLPRGamide and SFLPRGamide, from Hydra magnipapillata. Both the peptides shared the same C-terminal structure, -PRGamide, with Arg-VP. The nonapeptide proved to be Hym-355, a peptide that stimulates neuronal differentiation in hydra. Detailed evaluation by competitive enzyme-linked immunosorbent assay (ELISA) and double immunostaining using anti-VP and anti-Hym-355 antibodies enabled us to conclude that the two peptides account for a major part of the VP-like immunoreactivity in hydra nerve cells.

Amino Acid Sequence↗
PubMed2003

Deamidase inactivates a D-amino acid-containing Aplysia neuropeptide.

Membrane-catalyzed degradation of the cardioexcitatory peptide, Asn-D-Trp-Phe-NH(2) (N(d)WF-NH(2)), which was previously isolated from Aplysia, was investigated in relation to its inactivation mechanism. The principal degradation was deamidation of the C-terminal amide, producing biologically inert Asn-D-Trp-Phe-OH (N(d)WF-OH). Among membrane fractions prepared from different organs, the fraction from the ganglia showed the highest specific activity of the deamidation reaction. The deamidase activity was inhibited by Ebelactone B and the serine protease inhibitor, phenylmethanesulfonyl fluoride (PMSF), while the degradation of the synthetic stereoisomer, Asn-Trp-Phe-NH(2) (N(l)WF-NH(2)), was sensitive to the divalent cation-chelating agent, o-phenanthroline, and aminopeptidase inhibitors, amastatin and bestatin. The presence of D-Trp residue in the second position of N(d)WF-NH(2) endows this peptide not only with stereospecific bioactivity but also peptidase stability. The deamidation reaction seems to be the major inactivation mechanism for this peptide.

Amidohydrolases↗