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H Yanase

Publications and source records attributed to H Yanase.

At least 19 recordsLinked to original sources
PubMed2001

Possible involvement of ERK 1/2 in UVA-induced melanogenesis in cultured normal human epidermal melanocytes.

UV-induced melanogenesis is a well known physiological response of human skin exposed to solar radiation; however, the signaling molecules involved in the stimulation of melanogenesis in melanocytes following UV exposure remain unclear. In this study we induced melanogenesis in vitro in normal human epidermal melanocytes using a single irradiation with UVA at 1 kJ/m2 and examined the potential involvement of mitogen-activated protein kinases (MAPK) as UVA-responsive signaling molecules in those cells. UVA irradiation did not affect the proliferation of melanocytes, but it did increase tyrosinase mRNA expression, which reached a maximum level 4 hr after UVA irradiation. The amount of tyrosinase protein, as quantitated by immunoblotting, was also increased at 24 hr following UVA irradiation. Among the MAPK examined, extracellular signal-related kinase (ERK) 1/2 was phosphorylated within 15 min of UVA irradiation, but no such phosphorylation was observed for c-Jun N-terminal kinases (JNK) or p38. Accordingly, the activity of ERK1/2 was also increased shortly after UVA irradiation. These responses of ERK1/2 to UVA irradiation were markedly inhibited when cells were pre-treated with N-acetyl-L-cysteine, an antioxidant, or with suramin, a tyrosine kinase receptor inhibitor. The formation of (6-4)photoproducts or cyclobutane pyrimidine dimers was not detected in cellular DNA after UVA irradiation. These findings suggest that a single UVA irradiation-induced melanogenesis is associated with the activation of ERK1/2 by upstream signals that originate from reactive oxygen species or from activated tyrosine kinase receptors, but not from damaged DNA.

Acetylcysteine↗
PubMed2001

Cellular localization of the diazepam binding inhibitor (DBI) in the gastrointestinal tract of mice and its coexistence with the fatty acid binding protein (FABP).

The diazepam binding inhibitor (DBI), initially isolated as an endogenous 10-kDa polypeptide from the brain, has the ability to displace ligands from benzodiazepine binding sites on gamma-aminobutyric acid (GABA) receptors. However, DBI is widely distributed outside the brain, with the highest expression in the intestine. The present in situ hybridization study revealed the cellular expression of DBI mRNA throughout the gastrointestinal tract of mice, showing it to be intensely expressed in the spinous layer in the stratified squamous epithelium of the oral cavity, esophagus and forestomach, in surface mucous cells in the glandular stomach, and in columnar (absorptive) cells of the intestinal villi. A precise identification of DBI-expressing cell types was confirmed immunohistochemically, although the expressing cells detectable by the two histochemical methods differed slightly in their extension. Noteworthily, DBI always coexisted with the fatty acid binding protein (FABP), which participates in the uptake and metabolic processing of long chain fatty acids. In addition to the biochemical finding that DBI is identical with the acyl-CoA binding protein (ACBP), the distributional patterns of DBI and its colocalization with FABPs suggests its involvement in the absorption and metabolism of lipid in the epithelia of the digestive tract.

Animals↗
PubMed2000

Protective effect of gamma-glutamylethylamide (theanine) on ischemic delayed neuronal death in gerbils.

We examined the protective effect of gamma-glutamylethylamide (theanine) on ischemic delayed neuronal death in field CA1 of the gerbil hippocampus. One microliter of theanine from each three concentrations (50, 125 and 500 microM) was administered through the lateral ventricle 30 min before ischemia. Transient forebrain ischemia was induced by bilateral occlusion of the common carotid arteries for 3 min under careful control of brain temperature at approximately 37 degrees C. Seven days after ischemia, the number of intact CA1 neurons in the hippocampus was assessed. Ischemia-induced neuronal death in hippocampal CA1 region was significantly prevented in a dose-dependent manner in the theanine-pretreated groups. These findings indicate that theanine might be useful clinically for preventing ischemic neuronal damage.

Animals↗
PubMed2000

Neovascularization with blood-brain barrier breakdown in delayed neuronal death.

Various kinds of acute pathological events in the central nervous system, such as ischemia, hemorrhage, and trauma, often cause brain edema. The edema may advance for days or weeks while inducing extensive damage in neural function, regardless of the extent of the original damage, and often results in death. Delayed edema is thought to be vasogenic; however, the mechanism underlying edema induction remains unknown. We found delayed vascular cell proliferation with a blood-brain barrier breakdown in and around the gerbil CA1 hippocampus, a region known to be involved in delayed apoptotic neuronal death 2-6 days after transient ischemia. Vascular cell proliferation, assessed by (3)H-thymidine incorporation, was most prominent 4-6 days after ischemia, and extravasation of exogenously applied dye or endogenous serum albumin from blood vessels was observed concomitantly. We propose neovascularization in delayed neuronal death as a cause of brain edema advancing days after neurological events.

Animals↗
PubMed2000

Degradation of the metal-cyano complex tetracyanonickelate (II) by Fusarium oxysporum N-10.

A fungus with the ability to utilize a metalcyano compound, tetracyanonickelate (II) ¿K2[Ni (CN)4]; TCN¿, as its sole source of nitrogen was isolated from soil and identified as Fusarium oxysporum N-10. Both intact mycelia and cell-free extract of the strain catalyzed hydrolysis of TCN to formate and ammonia and produced formamide as an intermediate, thereby indicating that a hydratase and an amidase sequentially participated in the degradation of TCN. The enzyme catalyzing the hydration of TCN was purified approximately ten-fold from the cell-free extract of strain N-10 with a yield of 29%. The molecular mass of the active enzyme was estimated to be 160 kDa. The enzyme appears to exist as a homotetramer, each subunit having a molecular mass of 40 kDa. The enzyme also catalyzed the hydration of KCN, with a cyanide-hydrating activity 2 x 10(4) times greater than for TCN. The kinetic parameters for TCN and KCN indicated that hydratase isolated from F. oxysporum was a cyanide hydratase able to utilize a broad range of cyano compounds and nitriles as substrates.

Amino Acid Sequence↗
PubMed2000

Morphology and functional roles of synoviocytes in the joint.

The joint capsule exhibits a unique cellular lining in the luminal surface of the synovial membrane. The synovial intimal cells, termed synoviocytes, are believed to be responsible for the production of synovial fluid components, for absorption from the joint cavity, and for blood/synovial fluid exchanges, but their detailed structure and function as well as pathological changes remain unclear. Two types of synoviocytes, macrophagic cells (type A cells) and fibroblast-like cells (type B cells) have been identified. Type A synoviocytes are non-fixed cells that can phagocytose actively cell debris and wastes in the joint cavity, and possess an antigen-presenting ability. These type A cells, derived from blood-borne mononuclear cells, can be considered resident macrophages (tissue macrophages) like hepatic Kupffer cells. Type B synoviocytes are characterized by the rich existence of rough endoplasmic reticulum, and dendritic processes which form a regular network in the luminal surface of the synovial membrane. Their complex three-dimensional architecture was first revealed by our recent scanning electron microscopy of macerated samples. The type B cells, which are proper synoviocytes, are involved in production of specialized matrix constituents including hyaluronan, collagens and fibronectin for the intimal interstitium and synovial fluid. The proliferative potentials of type B cells in loco are much higher than type A cells, although the transformation of subintimal fibroblasts into type B cells can not be excluded. In some mammals, type B cells show features suggesting endocrine and sensory functions, but these are not recognized in other species. The synoviocytes, which form a discontinuous cell layer, develop both fragmented basement membranes around the cells and junctional apparatus such as desmosomes and gap junctions. For an exact understanding of the mechanism of arthritis, we need to establish the morphological background of synoviocytes as well as their functions under normal conditions.

Animals↗
PubMed2000

Cervical myelopathy due to an osteochondroma in a 73-year-old female. The oldest case in the literature.

An osteochondroma is a common developmental tumor of bone characterized by abnormal peri-physeal ectopic enchondral ossification. This results in a cartilage-capped subperiosteal bony projection, which may be either sessile or pedunculated. These lesions are said to grow until skeletal maturity. The cartilage cap is thought to become thinner as the patient ages beyond skeletal maturity. Apparent growth beyond skeletal maturity may be a sign of malignant conversion, usually to a chondroma. Osteochondromas are usually appreciated in the first decades of life, and are most commonly located in the extremities, usually in the knees, ankles, or wrists. Clinical complaints generally relate to the mass effect of the lesion. Solitary osteochondromas of the axial skeleton are less common and may present with a neurological deficit. We report on such a case, in a woman significantly older than other cases described in the literature.

Aged↗
PubMed1999

Protective effect of prostaglandin I(2) analogs on ischemic delayed neuronal damage in gerbils.

We found a novel subtype of prostaglandin (PG) I(2) receptor (IP(2)) expressed in the central nervous system. Recently we have demonstrated that (15R)-16-m-tolyl-17,18,19, 20-tetranorisocarbacyclin (15R-TIC) and 15-deoxy-16-m-tolyl-17,18,19, 20-tetranorisocarbacyclin (15-deoxy-TIC), IP(2)-specific ligands, significantly prevented high (50%) oxygen-induced apoptotic neuronal death in cultured hippocampal neurons. We report here a potent neuroprotective effect of such analogs on delayed neuronal death of hippocampal CA1 neurons following transient ischemia for 3 min in gerbils. (15S)-16-m-tolyl-17,18,19,20-tetranorisocarbacyclin (15S-TIC), which nonselectively acts both on the PGI(2) receptor expressed in the peripheral tissue (IP(1)) and on IP(2), also showed a neuroprotective effect on such an ischemic model at higher doses than those for 15R-TIC and 15-deoxy-TIC. These PGI(2) analogs did not affect brain temperature, indicating that the agents showed the neuroprotective effect not by a hypothermic effect, but rather by the direct action on neurons.

Animals↗
PubMed1999

Ischemia-induced glutamate release in the dentate gyrus. A microdialysis study in the gerbil.

The levels of extracellular glutamate were measured in the dentate gyrus by using an in vivo brain microdialysis method to determine whether the ischemia-induced glutamate release might be correlated with the neuronal vulnerability to ischemia. A microdialysis membrane was placed in CA4 (vulnerable to ischemia) and the molecular and granule cell layers of the dentate gyrus (resistant to ischemia) of gerbils. A significant increase in glutamate levels was induced in the normal dentate gyrus during 10-min ischemia. The increase was completely suppressed during the first 5 min of ischemia when CA4 neurons were eliminated. Thus, it was indicated that during the first 5 min of ischemia glutamate was released mostly from CA4 neurons but not from granule cells of the dentate gyrus. During the second half of 10-min ischemia, a significant increase in glutamate release was induced even in the dentate gyrus where CA4 neurons were eliminated; this increase was significantly suppressed by inhibiting proliferation of astrocytes. A large part of glutamate that was released during the second half of 10-min ischemia was considered to be attributable to glutamate release from astrocytes.

Animals↗
PubMed1999

Organization of the genes involved in the ribulose monophosphate pathway in an obligate methylotrophic bacterium, Methylomonas aminofaciens 77a.

The 4.4-kb PstI fragment harboring the gene encoding 3-hexulose-6-phosphate synthase, rmpA, which was previously cloned from the chromosome of an obligate methylotroph, Methylomonas aminofaciens 77a, was investigated in detail. In addition to the rmpA gene, the fragment contained three open reading frames encoding transaldolase (rmpD), IS10-R (rmpI), and 6-phospho-3-hexuloisomerase (PHI) (rmpB). The rmpB gene product was overproduced in Escherichia coli cells, purified to homogeneity, and then enzymatically identified as PHI. The gene organization of the ribulose monophosphate pathway enzymes together with a transposon, IS10-R, is discussed from both evolutionary and regulatory aspects.

Aldehyde-Lyases↗
PubMed1999

Stereoselective reduction of ethyl 4-chloro-3-oxobutanoate by Escherichia coli transformant cells coexpressing the aldehyde reductase and glucose dehydrogenase genes.

The asymmetric reduction of ethyl 4-chloro-3-oxobutanoate (COBE) to ethyl (R)-4-chloro-3-hydroxybutanoate [(R)-CHBE] using Escherichia coli cells, which coexpress both the aldehyde reductase gene from Sporobolomyces salmonicolor and the glucose dehydrogenase (GDH) gene from Bacillus megaterium as a catalyst was investigated. In an organic solvent-water two-phase system, (R)-CHBE formed in the organic phase amounted to 1610 mM (268 mg/ml), with a molar yield of 94.1% and an optical purity of 91.7% enantiomeric excess. The calculated turnover number of NADP+ to CHBE formed was 13,500 mol/mol. Since the use of E. coli JM109 cells harboring pKAR and pACGD as a catalyst is simple, and does not require the addition of GDH or the isolation of the enzymes, it is highly advantageous for the practical synthesis of (R)-CHBE.

Acetoacetates↗
PubMed1999

CNS-specific prostacyclin ligands as neuronal survival-promoting factors in the brain.

Prostacyclin (PGI2) is a critical regulator of the cardiovascular system, via dilatation of vascular smooth muscle and inhibition of platelet aggregation (Moncada, S. 1982, Br. J. Pharmacol., 76, 3). Our previous studies demonstrated that a novel subtype of PGI2 receptor, which is clearly distinct from a peripheral subtype in terms of ligand specificity, is expressed in the rostral region of the brain, e.g. cerebral cortex, hippocampus, thalamus and striatum, and that (15R)-16-m-17,18,19,20-tetranorisocarbacyclin (15R-TIC) and 15-deoxy-16-m-17,18,19,20-tetranorisocarbacyclin (15-deoxy-TIC) specifically bind to the central nervous system (CNS)-specific PGI2 receptor. Here, we report that these CNS-specific PGI2 receptor ligands, including PGI2 itself, prevented the neuronal death. They prevented apoptotic cell death of hippocampal neurons induced by high (50%) oxygen atmosphere, xanthine + xanthine oxidase, and serum deprivation. IC50s for neuronal death were approximately 30 and 300 nM for 15-deoxy-TIC and 15R-TIC, respectively, which well correlated with the binding potency for the CNS-specific PGI2 receptor. 6-Keto-PGF1alpha (a stable metabolite of PGI2), peripheral nervous system-specific PGI2 ligands and other prostaglandins (PGs) than PGI2 did not show such neuroprotective effects. In vivo, 15R-TIC protected CA1 pyramidal neurons against ischaemic damage in gerbils. These results indicate that CNS-specific PGI2 ligands have neuronal survival-promoting activity both in vitro and in vivo, and may represent a new type of therapeutic drug for neurodegeneration.

Animals↗
PubMed1999

Cloning, overexpression, and mutagenesis of the Sporobolomyces salmonicolor AKU4429 gene encoding a new aldehyde reductase, which catalyzes the stereoselective reduction of ethyl 4-chloro-3-oxobutanoate to ethyl (S)-4-chloro-3-hydroxybutanoate.

We cloned and sequenced the gene encoding an NADPH-dependent aldehyde reductase (ARII) in Sporobolomyces salmonicolor AKU4429, which reduces ethyl 4-chloro-3-oxobutanoate (4-COBE) to ethyl (S)-4-chloro-3-hydroxybutanoate. The ARII gene is 1,032 bp long, is interrupted by four introns, and encodes a 37,315-Da polypeptide. The deduced amino acid sequence exhibited significant levels of similarity to the amino acid sequences of members of the mammalian 3beta-hydroxysteroid dehydrogenase-plant dihydroflavonol 4-reductase superfamily but not to the amino acid sequences of members of the aldo-keto reductase superfamily or to the amino acid sequence of an aldehyde reductase previously isolated from the same organism (K. Kita, K. Matsuzaki, T. Hashimoto, H. Yanase, N. Kato, M. C.-M. Chung, M. Kataoka, and S. Shimizu, Appl. Environ. Microbiol. 62:2303-2310, 1996). The ARII protein was overproduced in Escherichia coli about 2, 000-fold compared to the production in the original yeast cells. The enzyme expressed in E. coli was purified to homogeneity and had the same catalytic properties as ARII purified from S. salmonicolor. To examine the contribution of the dinucleotide-binding motif G(19)-X-X-G(22)-X-X-A(25), which is located in the N-terminal region, during ARII catalysis, we replaced three amino acid residues in the motif and purified the resulting mutant enzymes. Substrate inhibition of the G(19)-->A and G(22)-->A mutant enzymes by 4-COBE did not occur. The A(25)-->G mutant enzyme could reduce 4-COBE when NADPH was replaced by an equimolar concentration of NADH.

Acetoacetates↗
PubMed1999

Evidence of horizontal transfer of the EcoO109I restriction-modification gene to Escherichia coli chromosomal DNA.

A DNA fragment carrying the genes coding for EcoO109I endonuclease and EcoO109I methylase, which recognize the nucleotide sequence 5'-(A/G)GGNCC(C/T)-3', was cloned from the chromosomal DNA of Escherichia coli H709c. The EcoO109I restriction-modification (R-M) system was found to be inserted between the int and psu genes from satellite bacteriophage P4, which were lysogenized in the chromosome at the P4 phage attachment site of the corresponding leuX gene observed in E. coli K-12 chromosomal DNA. The sid gene of the prophage was inactivated by insertion of one copy of IS21. These findings may shed light on the horizontal transfer and stable maintenance of the R-M system.

Amino Acid Sequence↗
PubMed1999

Unique localization of protein gene product 9.5 in type B synoviocytes in the joints of the horse.

Fibroblast-like (Type B) synoviocytes are cells in the synovial membrane that are responsible for production of both synovial fluid and the extracellular matrix in the synovial intima. Immunostaining of the horse synovial membrane for protein gene product (PGP) 9.5, which is a neuron-specific ubiquitin C-terminal hydrolase, demonstrated selective localization of the immunoreactivity in a synoviocyte population different from acid phosphatase-positive Type A synoviocytes. The immunoreactive cells were lined up in the synovial intima and extended dendritic processes towards the joint cavity to form a dense plexus on the surface. Electron microscopic examination clearly identified the PGP 9.5-immunoreactive cells as Type B synoviocytes characterized by developed rough endoplasmic reticulum and free ribosomes. Immunoreactivity for PGP 9.5 was diffusely distributed throughout the cytoplasm, including the tips of fine processes. Western and Northern blot analyses could not distinguish the corresponding protein and mRNA obtained from the brain and synovial membrane. The existence of the neuron-specific PGP 9.5 in Type B synoviocytes suggests a common mechanism regulating the protein metabolism between neurons and synoviocytes, and also provides a new cytochemical marker for identification of the cells.

Animals↗
PubMed1999

A new carboxylesterase from Brevibacterium linens IFO 12171 responsible for the conversion of 1,4-butanediol diacrylate to 4-hydroxybutyl acrylate: purification, characterization, gene cloning, and gene expression in Escherichia coli.

A carboxylesterase that is responsible for conversion of 1,4-butanediol diacrylate (BDA) to 4-hydroxybutyl acrylate (4HBA) was found in Brevibacterium lines IFO 12171, and purified to homogeneity. The purified enzyme was active toward a variety of diesters of ethylene glycol, 1,4-butanediol, and 1,6-hexanediol. The K(m) and kcat of the enzyme for BDA were 3.04 mM and 203,000 s-1, respectively. The reaction with the purified enzyme gave 98 mM 4HBA from 100 mM BDA for 60 min. The enzyme gene was cloned from the chromosomal DNA of the bacterium. The open reading frame encoding the enzyme was 1176 bp long, corresponding to a protein of 393 amino acid residues (molecular mass = 42,569 Da). The deduced amino acid sequence contained the tetra peptide motif sequence, STTK, and the serine residue was confirmed to be the catalytic center of BDA esterase by site-directed mutagenesis for several amino acid residues. The gene was expressed in Escherichia coli under the control of the lac promoter, and the gene product (a fusion protein with 6 amino acid residues from beta-galactosidase) showed the same catalytic properties as the enzyme from the parent strain.

Acrylates↗
PubMed1999

Three-dimensional ultrastructure of synoviocytes in the horse joint as revealed by the scanning electron microscope.

The synovial membrane displays a superficial cellular lining composed of two types of synoviocytes: "absorptive" macrophages (type A cells) and "secretory" fibroblast-like cells (type B cells). The types are intermingled and extend a variety of processes, rendering the cellular architecture of the synovial membrane difficult to visualize. Previous electron microscopic and histochemical studies failed to demonstrate the entire shape of synoviocytes, except our immunohistochemical study for protein gene product 9.5 in the horse joint. The present SEM study is the first to demonstrate the three-dimensional ultrastructure of synoviocytes as well as their distribution in the synovial membrane, using macerated samples from the horse carpal joints. The equine synovial membrane was largely covered by conspicuously developed synovial villi. Type A synoviocytes were closely similar to macrophages in regard to surface structure, and showed uneven distribution with the densest occurrence around the tips of the synovial villi. In the basal half of villi, type B synoviocytes, which were situated in close proximity to the synovial cavity, projected thick processes horizontally and intertwined to form a regular network of processes on the synovial surface. Those in the upper half of the villi were located in the abluminal layers and protruded an antenna-like process into the joint cavity with tips covered with long microvilli, in addition to forming the superficial plexus of processes. Type B cells were also provided with fine, membranous extensions that tended to cover the surface of synovial intima. The meshwork of horizontal processes, the antenna-like processes, and the membranous processes imply advantages in not only secretion but also sensation and regulation of the barrier function in the synovial membrane.

Animals↗