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Y Ohsawa

Publications and source records attributed to Y Ohsawa.

At least 19 recordsLinked to original sources
PubMed2005

Reduced amplitude of the sural nerve sensory action potential in PARK2 patients.

The authors performed nerve conduction studies in nine PARK2 and eight idiopathic Parkinson disease patients and found a significant reduction of sural sensory nerve action potential (SNAP) amplitude in eight PARK2 patients who mostly remained asymptomatic. These data suggest that sensory axonal neuropathy may be a common clinical feature of PARK2 and a reduced amplitude of sural SNAP could be a diagnostic indicator of PARK2.

Action Potentials↗
PubMed2005

Regulatory T-cells infiltrate periodontal disease tissues.

CD4+CD25+ regulatory T (Tr) cells are critical in regulating the immune response and thereby play an important role in the defense against infection and control of autoimmune diseases. Our previous studies demonstrated the involvement of autoimmune responses in periodontitis. The aim of this study was to identify CD4+CD25+ Tr cells in periodontitis tissues and compare them with those in gingivitis tissues. Immunohistological analysis of CD4, CD25, and CTLA-4 and the gene expression analysis of FOXP3, TGF-beta1, and IL-10 on gingival biopsies revealed the presence of CD4+CD25+ Tr cells in all tissues. In periodontitis, the percentage of CD4+CD25+ Tr cells increased with increasing proportions of B-cells relative to T-cells. FOXP3, a characteristic marker for CD4+CD25+ Tr cells, TGF-beta1 and IL-10 were expressed more highly in periodontitis compared with gingivitis. These findings suggest that CD4+CD25+ Tr cells and possibly other regulatory T-cell populations do exist and may play regulatory roles in periodontal diseases.

Aged↗
PubMed2004

T-cell clonality to Porphyromonas gingivalis and human heat shock protein 60s in patients with atherosclerosis and periodontitis.

Individuals with periodontitis have been reported to have a significantly increased risk of developing coronary heart disease. Several studies have demonstrated that the immune response to heat shock protein 60 (HSP60) may be involved in the pathogenesis of both atherosclerosis and chronic periodontitis. To investigate this possible link between these diseases, cellular and humoral immune responses to HSP60 in atherosclerosis patients were compared with those in periodontitis patients and healthy subjects using human and Porphyromonas gingivalis HSP60 (GroEL) as antigens. Antibody levels to both human and P. gingivalis HSP60s were the highest in atherosclerosis patients, followed by periodontitis patients and healthy subjects. Clonal analysis of the T cells clearly demonstrated the presence of not only human HSP60- but also P. gingivalis GroEL-reactive T-cell populations in the peripheral circulation of atherosclerosis patients. Furthermore, these HSP60-reactive T cells seemed to be present in atherosclerotic lesions in some patients. These results suggest that T-cell clones with the same specificity may be involved in the pathogenesis of the different diseases.

Adult↗
PubMed2003

Regulation of FLRG expression in rat primary astroglial cells and injured brain tissue by transforming growth factor-beta 1 (TGF-beta 1).

Follistatin-related gene (FLRG) is a member of the follistatin family of proteins and interacts with transforming growth factor (TGF) superfamily proteins like follistatin. To understand the expression level of FLRG in brain tissue, we examined whether primary neurons and glial cells from rat embryos express FLRG mRNA and produce its protein product. FLRG and follistain mRNAs were mainly expressed in astroglial cells, while activin A mRNA was abundant in primary neurons. TGF-beta1 highly enhanced expression levels of FLRG mRNA in astroglial cells, compared with those of follistatin and activin A mRNAs. Particularly, TGF-beta1 facilitated the secretion of FLRG protein from primary astroglial cells in a dose-dependent manner. Moreover, changes in expression levels of FLRG mRNA and protein in brain tissue were also analyzed after a penetrating injury, using quantitative polymerase chain reactin (PCR) and immunohistochemical methods. Expression levels of FLRG mRNA were significantly increased in damaged regions after penetrating injury together with those of activin A and TGF-beta1 mRNAs. Immunohistochemical observations showed that positive signals of FLRG protein were colocalized in glial fibrillary acidic protein-positive reactive astroglial cells located in damaged regions after a penetrating injury. The expression of follistatin mRNA rather decreased in damage regions after the brain injury. These results suggest that FLRG is synthesized in and secreted from astroglial cells. In particular, FLRG, but not follistatin, may play a role in the regulation of activin A in brain wound healing in response to TGF-beta1.

Animals↗
PubMed2002

Oligoclonal accumulations of T-cell clones in gingivitis and periodontitis lesions.

Gingivitis and periodontitis have distinct clinical and immunopathological characteristics. We have previously demonstrated that T cells infiltrating periodontitis lesions recognize a restricted repertoire of antigens or antigenic epitopes. However, the clonality of T cells in the gingivitis lesion is not known. Therefore, we carried out a clonal analysis of T cells infiltrating gingivitis lesions using combined reverse transcription-polymerase chain reaction and single-strand conformation polymorphism (SSCP) analysis. As with periodontitis lesions, SSCP analysis demonstrated the emergence of a number of distinct bands suggesting clonal accumulation in the gingivitis lesion. Although the mean number of distinct bands in gingival tissue was significantly higher than that in peripheral blood mononuclear cells, numerical analysis clearly demonstrated that there was no difference in the total number of bands in gingival tissue specimens between the different disease types. Although there were slight variations in the number of distinct bands in each Vbeta family, there was no significant difference between gingivitis lesions and periodontitis lesions. These results demonstrate that antigen-specific T-cell responses also take place in gingivitis lesions. It remains to be determined, however, what role these antigen-specific T cells play and what antigens the T cells recognize in the pathogenesis of periodontal disease.

Clone Cells↗
PubMed2001

Requirement of DNase II for definitive erythropoiesis in the mouse fetal liver.

Mature erythrocytes in mammals have no nuclei, although they differentiate from nucleated precursor cells. The mechanism by which enucleation occurs is not well understood. Here we show that deoxyribonuclease II (DNase II) is indispensable for definitive erythropoiesis in mouse fetal liver. No live DNase II-null mice were born, owing to severe anemia. When mutant fetal liver cells were transferred into lethally irradiated wild-type mice, mature red blood cells were generated from the mutant cells, suggesting that DNase II functions in a non-cell-autonomous manner. Histochemical analyses indicated that the critical cellular sources of DNase II are macrophages present at the site of definitive erythropoiesis in the fetal liver. Thus, DNase II in macrophages appears to be responsible for destroying the nuclear DNA expelled from erythroid precursor cells.

Animals↗
PubMed2001

Oxidation-active flavin models: oxidation of alpha-hydroxy acids by benzo-dipteridine bearing metal-binding site in the presence of divalent metal ion and base in organic solvents.

The oxidizing ability of benzo-dipteridine bearing a bipyridin-6-ylmethyl moiety (4) was found to be increased with Zn(2+) by approximately 10(3)-fold for sulfite addition in MeOH and approximately 10(2)-fold for oxidation of an NADH model in MeCN. It was found for the first time that 4 is able to oxidize alpha-hydroxy acids to alpha-keto acids in the presence of a divalent metal ion such as Zn(2+), Co(2+), and Ni(2+) and an amine base in MeCN or t-BuOH, whereas benzo-dipteridine having a bipyridin-5-ylmethyl moiety (3) is unable to oxidize them under the same conditions. The oxidation reaction was kinetically investigated including the kinetic isotope effect for deuterated mandelic acids (k(H)/k(D) = 2.1-3.7) and the Hammett plots for substituted mandelic acids (V-shaped plots). In the reaction of alpha-substituted alpha-hydroxy acids such as alpha-methyl mandelic and benzylic acids with 4, novel oxidative decarboxylation was found to take place, giving acetophenone and benzophenone, respectively. The oxidation mechanism for mandelic acid was proposed to proceed via a ternary complex of 4.Zn(2+).PhCH(OH)CO(2)(-), in which alpha-oxyanion of mandelate attacks C(4a)-position of 4 to form an adduct followed by 1,2-elimination to afford benzoyl formate and 2e-reduced 4. The roles of the metal ion were proposed as follows; (i) activation of 4, (ii) substrate-binding site, and (iii) activation of the bound alpha-hydroxy acid by lowering pK(a)'s of alpha-OH and alpha-CH. This is a first example that a flavin model oxidizes alpha-hydroxy acids in the presence of a metal ion.

Journal Article↗
PubMed2001

Elevated proportion of natural killer T cells in periodontitis lesions: a common feature of chronic inflammatory diseases.

Although periodontitis is a chronic inflammatory disease caused by a group of so-called periodontopathic bacteria, autoimmune mechanisms have also been implicated in the disease process. Recently, a unique subset of lymphocytes designated natural killer (NK) T cells expressing the Valpha24JalphaQ invariant T cell receptor (TCR) has been reported to have a regulatory role in certain autoimmune diseases. Therefore, we investigated the proportion of the invariant Valpha24JalphaQ TCR within the Valpha24 T cell population in periodontitis lesions and gingivitis lesions using single-strand conformation polymorphism methodology. NK T cells were identified with a specific JalphaQ probe whereas the total Valpha24 TCR was identified using an internal Calpha probe. NK T cells were a significant proportion of the total Valpha24 population both in periodontitis lesions and to a lesser extent in gingivitis lesions but not in the peripheral blood of either periodontitis patients or nondiseased controls. Using immunohistochemistry, some of Valpha24(+) cells in the periodontitis lesions seemed to associate with CD1d(+) cells, which are specific antigen-presenting cells for NK T cells. Although the mechanism underlying the elevation of NK T cells in periodontitis and in gingivitis lesions remains unclear, it can be postulated that NK T cells are recruited to a play regulatory role in the immune response to bacterial infection.

Adult↗
PubMed2001

Interleukin-10 gene promoter polymorphism in Japanese patients with adult and early-onset periodontitis.

BACKGROUND: IL-10 is an anti-inflammatory cytokine, which may modulate disease expression in chronic inflammatory periodontal disease. 3 dimorphic polymorphisms within the IL-10 gene promoter have recently been identified and appear to influence regulation of its expression. AIM: The aim of the present study was to investigate whether the promoter polymorphisms are associated with adult periodontitis (AP) and generalized early-onset periodontitis (G-EOP). METHODS: Genomic DNA was obtained from 34 AP patients, 18 G-EOP patients and 52 controls. The promoter region between -506 and -1140 was amplified by polymerase chain reaction, and polymorphisms were detected by nucleotide sequencing. RESULTS: The haplotype frequencies in Japanese were quite different from those of Caucasian and were even slightly different from those of southern Chinese with systemic lupus erythematosus. We found no significant difference in allele or haplotype frequencies between patients and controls. CONCLUSIONS: IL-10 production may be regulated within the complex cytokine network in chronic inflammatory periodontal disease, rather than the gene polymorphisms.

Adult↗
PubMed2001

Elevated mRNA expression for supervillin and vascular endothelial growth factor in human neutrophils stimulated with lipopolysaccharide from Porphyromonas gingivalis.

Differential gene expression was examined in human neutrophils stimulated with lipopolysaccharide from Porphyromonas gingivalis (P. gingivalis-LPS) using RNA fingerprinting by arbitrarily primed polymerase chain reaction (RAP-PCR). LPS from Escherichia coli (E. coli-LPS) was used as control. More than 200 differently expressed transcripts were found in 8 subjects showing differential regulation at the transcriptional level. Densitometric analyses revealed that 42-100 genes were upregulated, while 53-116 genes were downregulated by P. gingivalis-LPS compared with E. coli-LPS. The results of sequencing identification showed the presence of supervillin (SVIL) and vascular endothelial growth factor (VEGF) genes in the clones which were upregulated by P. gingivalis-LPS. Consequently, semiquantitative analyses proved that the level of mRNA for SVIL and VEGF were significantly higher in P. gingivalis-LPS-stimulated neutrophils than in other bacterial (E. coli, Actinobacillus actinomycetemcomitans, Prevotella intermedia) LPS- or synthetic lipid A-stimulated neutrophils. Our findings suggest that an elevated mRNA expression for SVIL could be associated with impaired function of neutrophils when stimulated by P. gingivalis-LPS. Further, the VEGF mRNA over-expression might be related to the pathogenesis of P. gingivalis-associated periodontitis. The RAP-PCR technique used in this study enabled us to identify a number of P. gingivalis-LPS regulated genes which hitherto have not been reported.

Adult↗
PubMed2001

VCP/p97 in abnormal protein aggregates, cytoplasmic vacuoles, and cell death, phenotypes relevant to neurodegeneration.

Neuronal cell death, abnormal protein aggregates, and cytoplasmic vacuolization are major pathologies observed in many neurodegenerative disorders such as the polyglutamine (polyQ) diseases, prion disease, Alzheimer disease, and the Lewy body diseases, suggesting common mechanisms underlying neurodegeneration. Here, we have identified VCP/p97, a member of the AAA+ family of ATPase proteins, as a polyQ-interacting protein in vitro and in vivo, and report on its characterization. Endogenous VCP co-localized with expanded polyQ (ex-polyQ) aggregates in cultured cells expressing ex-polyQ, with nuclear inclusions in Huntington disease patient brains, and with Lewy bodies in patient samples. Moreover, the expression of VCP mutants with mutations in the 2nd ATP binding domain created cytoplasmic vacuoles, followed by cell death. Very similar vacuoles were also induced by ex-polyQ expression or proteasome inhibitor treatment. These results suggest that VCP functions not only as a recognition factor for abnormally folded proteins but also as a pathological effector for several neurodegenerative phenotypes. VCP may thus be an ideal molecular target for the treatment of neurodegenerative disorders.

Adenosine Triphosphatases↗
PubMed2001

Expression of proteinases and inflammatory cytokines in subchondral bone regions in the destructive joint of rheumatoid arthritis.

OBJECTIVE: We previously described abnormalities in the bone marrow of patients with rheumatoid arthritis (RA), but were able to shed little light on the pathogenic roles of inflammatory cytokines and proteinases in joint destruction in the subchondral region in RA. This is the first report to describe the co-localization of cytokines and proteinases in this area. METHODS: Decalcified paraffin-embedded sections from 10 patients with RA and five patients with osteoarthritis (OA) were examined for the immunolocalization of cathepsins B, K and L and the localization of messenger RNAs for interleukin 1beta (IL-1beta), tumour necrosis factor alpha (TNF-alpha) and matrix metalloproteinase 9 (MMP-9). The cells were double-stained with anti-CD68 or anti-prolyl 4-hydroxylase (PH) antibody. RESULTS: An immunohistochemical study confirmed the expression of cathepsins B and L by CD68-positive mononuclear cells at the sites of significant cartilage and bone erosion from the subchondral region in all RA specimens. Osteoclast-like cells showed intense staining for cathepsin K and MMP-9. Osteoblast-like cells strongly expressed MMP-9. Analysis of serial sections revealed that expression of the IL-1beta and TNF-alpha genes occurred near that of the cathepsins and MMP-9 in the subchondral region. CONCLUSION: We conclude that inflammatory cytokines and tissue-damaging proteinases play important roles in joint destruction in the subchondral region in RA.

Adult↗
PubMed2001

Different distribution patterns of the two mannose 6-phosphate receptors in rat liver.

Two mannose 6-phosphate receptors, cation-dependent and -independent receptors (CDMPR and CIMPR), play an important role in the intracellular transport of lysosomal enzymes. To investigate functional differences between the two in vivo, their distribution was examined in the rat liver using immunohistochemical techniques. Positive signals corresponding to CIMPR were detected intensely in hepatocytes and weakly in sinusoidal Kupffer cells and interstitial cells in Glisson's capsule. In the liver acinus, hepatocytes in the perivenous region showed a more intense immunoreactivity than those in the periportal region. On the other hand, positive staining of CDMPR was detected at a high level in Kupffer cells, epithelial cells of interlobular bile ducts, and fibroblast-like cells, but the corresponding signal was rather weak in hepatocytes. In situ hybridization analysis also revealed a high level of expression of CIMPR mRNAs in hepatocytes and of CDMPR mRNA in Kupffer cells. By double immunostaining, OX6-positive antigen-presenting cells in Glisson's capsule were co-labeled with the CDMPR signal but were only faintly stained with anti-CIMPR. These different distribution patterns of the two MPRs suggest distinct functional properties of each receptor in liver tissue.

Animals↗
PubMed2001

Prevention of apoptosis of mammalian cells by the CED-3-cleaved form of CED-9.

CED-9 prevents apoptosis in embryonic cells of Caenorhabditis elegans but not in mammalian cells. We show here that the prevention of apoptosis in mammalian cells requires a CED-3-cleaved form (68-280) of CED-9 which is localized in the inner mitochondrial membrane. The viability of PC12 and HeLa cells was significantly increased after death stimuli when truncated CED-9 was expressed in these cells but full-length CED-9 did not. The truncated CED-9 expressed in these cells was largely localized to the inner mitochondrial and the endoplasmic reticulum membranes, while full-length CED-9 was detected mainly in endoplasmic reticulum fractions. Moreover, truncated CED-9 in purified mitochondria was resistant to trypsin digestion, but full-length CED-9 was not. These results suggest that the CED-3-cleaved form of CED-9 prevents apoptosis in mammalian cells by localizing to the inner mitochondrial membrane.

Animals↗
PubMed2001

Specific localization of lysosomal aminopeptidases in type II alveolar epithelial cells of the rat lung.

We previously demonstrated that lysosomal cysteine proteinases, cathepsins B, H, and L were localized in lysosomes of alveolar macrophages and bronchial epithelial cells in the rat lung, while cathepsin H, a typical aminopeptidase, was additionally distributed in lamellar bodies containing surfactant in type II alveolar epithelial cells (ISHII et al., 1991). The present immunohistochemical study further examined the localization of lysosomal aminopeptidases, cathepsin C, and tripeptidyl peptidase I (TPP-I) in the rat lung. Western blotting confirmed the presence of cathepsin C and TPP-I as active forms in the pulmonary tissue, showing 25 kD and 47 kD, respectively. Immunohisto/cytochemical observations demonstrated that positive staining for cathepsin C and TPP-I was more intensely localized in alveolar epithelial regions than in bronchial or bronchiolar epithelial cells. By double immunostaining using confocal laser microscopy, immunoreactivity for cathepsin H was found to be co-localized with that for cathepsin C or TPP-I in both type II cells and macrophages. Moreover, when doubly stained with anti-cathepsin C and ED2, single-positive type II cells could be clearly distinguished from double-positive macrophages in the alveolar region. Immunoelectron microscopy revealed the gold labeling of cathepsin C or TPP-I in multivesicular and composite bodies, and lamellar bodies of Type II cells. These results showing that lysosomal aminopeptidases such as cathepsin H, cathepsin C and TPP-I are localized in lamellar bodies of type II alveolar epithelial cells strongly argue for the participation of lysosomal aminopeptidases in the formation process of surfactant containing specific proteins.

Aminopeptidases↗
PubMed2000

Necrotic death pathway in Fas receptor signaling.

A caspase 8-deficient subline (JB6) of human Jurkat cells can be killed by the oligomerization of Fas-associated protein with death domain (FADD). This cell death process is not accompanied by caspase activation, but by necrotic morphological changes. Here, we show that the death effector domain of FADD is responsible for the FADD-mediated necrotic pathway. This process was accompanied by a loss of mitochondrial transmembrane potential (DeltaPsim), but not by the release of cytochrome c from mitochondria. Pyrrolidine dithiocarbamate, a metal chelator and antioxidant, efficiently inhibited the FADD-induced reduction of DeltaPsim and necrotic cell death. When human Jurkat, or its transformants, expressing mouse Fas were treated with Fas ligand or anti-mouse Fas antibodies, the cells died, showing characteristics of apoptosis. A broad caspase inhibitor (z-VAD-fmk) blocked the apoptotic morphological changes and the release of cytochrome c. However, the cells still died, and this cell death process was accompanied by a strong reduction in DeltaPsim, as well as necrotic morphological changes. The presence of z-VAD-fmk and pyrrolidine dithiocarbamate together blocked cell death, suggesting that both apoptotic and necrotic pathways can be activated through the Fas death receptor.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Cathepsin D deficiency induces lysosomal storage with ceroid lipofuscin in mouse CNS neurons.

Cathepsin D-deficient (CD-/-) mice have been shown to manifest seizures and become blind near the terminal stage [approximately postnatal day (P) 26]. We therefore examined the morphological, immunocytochemical, and biochemical features of CNS tissues of these mice. By electron microscopy, autophagosome/autolysosome-like bodies containing part of the cytoplasm, granular osmiophilic deposits, and fingerprint profiles were demonstrated in the neuronal perikarya of CD-/- mouse brains after P20. Autophagosomes and granular osmiophilic deposits were detected in neurons at P0 but were few in number, whereas they increased in the neuronal perikarya within days after birth. Some large-sized neurons having autophagosome/autolysosome-like bodies in the perikarya appeared in the CNS tissues, especially in the thalamic region and the cerebral cortex, at P17. These lysosomal bodies occupied the perikarya of almost all neurons in CD-/- mouse brains obtained from P23 until the terminal stage. Because these neurons exhibited autofluorescence, it was considered that ceroid lipofuscin may accumulate in lysosomal structures of CD-/- neurons. Subunit c of mitochondrial ATP synthase was found to accumulate in the lysosomes of neurons, although the activity of tripeptidyl peptidase-I significantly increased in the brain. Moreover, neurons near the terminal stage were often shrunken and possessed irregular nuclei through which small dense chromatin masses were scattered. These results suggest that the CNS neurons in CD-/- mice show a new form of lysosomal accumulation disease with a phenotype resembling neuronal ceroid lipofuscinosis.

Action Potentials↗