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Biomedical subjects

A Hayashi

Publications and source records attributed to A Hayashi.

At least 91 records · Page 5Linked to original sources
PubMed1999

Cloning and expression profile of mouse and human genes, Rnf11/RNF11, encoding a novel RING-H2 finger protein.

The RING finger (C3HC4-type zinc finger) is a variant zinc finger motif presents in a new family of proteins. A new member of the RING finger family was identified and its cDNA structures were determined in human and mouse. The predicted protein consisting of a 144 amino acid residues is very conservative between the two species and contains a canonical RING-H2 finger motif (C3H2C2) at the carboxyl-terminal region. The genes were designated as RNF11/Rnf11 for RING finger protein 11. A single 2.4-kb transcript of mouse Rnf11 was ubiquitously expressed in various fetal and adult mouse tissues by the Northern blot analysis. The human RNF11 gene was mapped on chromosome 1p31-p32 region, where frequent alterations have been observed in T-cell acute lymphoblastic leukemia.

Amino Acid Sequence↗
PubMed1999

A cyclophilin B gene encodes antigenic epitopes recognized by HLA-A24-restricted and tumor-specific CTLs.

We have studied Ags recognized by HLA class I-restricted CTLs established from tumor site to better understand the molecular basis of tumor immunology. HLA-A24-restricted and tumor-specific CTLs established from T cells infiltrating into lung adenocarcinoma recognized the two antigenic peptides encoded by a cyclophilin B gene, a family of genes for cyclophilins involved in T cell activation. These two cyclophilin B peptides at positions 84-92 and 91-99 induced HLA-A24-restricted CTL activity against tumor cells in PBMCs of leukemia patients, but not in epithelial cancer patients or in healthy donors. In contrast, the modified peptides at position 2 from phenylalanine to tyrosine, which had more than 10 times higher binding affinities to HLA-A24 molecules, could induce HLA-A24-restricted CTL activity against tumor cells in PBMCs from leukemia patients, epithelial cancer patients, or healthy donors. PHA-activated normal T cells were resistant to lysis by the CTL line or by these peptide-induced CTLs. These results indicate that a cyclophilin B gene encodes antigenic epitopes recognized by CTLs at the tumor site, although T cells in peripheral blood (except for those from leukemia patients) are immunologically tolerant to the cyclophilin B. These peptides might be applicable for use in specific immunotherapy of leukemia patients or that of epithelial cancer patients.

Adenocarcinoma↗
PubMed1999

cDNA cloning, tissue expression, and chromosomal assignment of a mouse gene, encoding a 127 kDa UV-damaged DNA binding protein which is defective in XPE cells.

A subset of xeroderma pigmentosum (XP) group E cells lack a factor of the UV-damaged DNA binding activity. Both 127 kDa and 48 kDa proteins have been reported to be responsible for the binding activity. A cDNA for the 127 kDa UV-damaged DNA-binding protein (p127-Ddb1) was isolated from a mouse fetal brain full length-enriched cDNA library, and an open reading frame of 1140 amino acids was identified. Reverse transcription-coupled polymerase chain reaction (RT-PCR) showed that mouse Ddb1 messenger is ubiquitously expressed in adult tissues as well as in embryo's. The gene was mapped to near the public locus D19Mit22 region of mouse chromosome 19.

Amino Acid Sequence↗
PubMed1999

Positively charged liposome functions as an efficient immunoadjuvant in inducing cell-mediated immune response to soluble proteins.

In order to design an optimized liposome immunoadjuvant for inducing cell-mediated immune response against soluble proteinaceous antigens, we investigated the effect of liposomal surface charge on the immunoadjuvant action. Positively charged liposomes containing soluble antigens functioned as a more potent inducer of antigen-specific cytotoxic T lymphocyte responses and delayed type hypersensitivity response than negatively charged and neutral liposomes containing the same concentrations of antigens. To clarify the reason of the differential immune response, we examined the delivery of soluble proteins by the liposomes into the cytoplasm of macrophages, using fragment A of diphtheria toxin (DTA) as a marker. We found that positively charged liposomes encapsulating DTA are cytotoxic to macrophages, while empty positively charged liposomes, DTA in negatively charged and neutral liposomes are not. Consistent with this, only macrophages pulsed with OVA in positively charged liposomes could significantly stimulate OVA-specific, class I MHC-restricted T cell hybridoma. These results suggest that the positively charged liposomes can deliver proteinaceous antigens efficiently into the cytoplasm of the macrophages/antigen-presenting cells, where the antigens are processed to be presented by class I MHC molecules to induce the cell-mediated immune response. Possible development of the safe and effective vaccine is discussed.

Adjuvants, Immunologic↗
PubMed1999

Identification of a gene coding for a protein possessing shared tumor epitopes capable of inducing HLA-A24-restricted cytotoxic T lymphocytes in cancer patients.

Genes encoding tumor epitopes that are capable of inducing CTLs against adenocarcinomas and squamous cell carcinomas, two major human cancers histologically observed in various organs, have rarely been identified. Here, we report a new gene from cDNA of esophageal cancer cells that encodes a shared tumor antigen recognized by HLA-A2402-restricted and tumor-specific CTLs. The sequence of this gene is almost identical to that of the KIAA0156 gene, which has been registered in GenBank with an unknown function. This gene encodes a Mr 140,000 protein that is expressed in the nucleus of all of the malignant tumor cell lines tested and the majority of cancer tissues with various histologies, including squamous cell carcinomas, adenocarcinomas, melanomas, and leukemia cells. However, this protein was undetectable in the nucleus of any cell lines of nonmalignant cells or normal tissues, except for the testis. Furthermore, this protein was expressed in the cytosol of all of the proliferating cells, including normal cells and malignant cells, but not in normal tissues, except for the testis and fetal liver. Two peptides of this protein were recognized by HLA-A2402-restricted CTLs and were able to induce HLA-A24-restricted and tumor-specific CTLs from peripheral blood mononuclear cells of most of HLA-A24+ cancer patients tested, but not from peripheral blood mononuclear cells of any healthy donors. These peptides may be useful in specific immunotherapy for HLA-A24+ cancer patients with various histological types.

Antigens, Neoplasm↗
PubMed1999

A novel vaccine delivery system using immunopotentiating fusogenic liposomes.

We previously reported the preparation and characterization of fusogenic liposomes (FLs), which have two highly immunogenic glycoproteins of the Sendai virus on their surface. In this report, we investigated the capacity of FLs to enhance antigen-specific humoral immunity in mice. FLs function as a lymphocyte mitogen with high immunogenicity consistent with viral envelope proteins. Markedly increased levels of anti-ovalbumin (OVA) antibody were detected in serum from mice immunized with OVA encapsulated in FLs compared to sera from mice immunized with free OVA or OVA encapsulated in plain liposomes. An anti-OVA antibody response was not observed in mice immunized with OVA simply mixed with empty FLs. These results indicate that FLs function as a novel immunoadjuvant in inducing antigen-specific antibody production.

Adjuvants, Immunologic↗
PubMed1999

PKCnu, a new member of the protein kinase C family, composes a fourth subfamily with PKCmu.

Members of the protein kinase C (PKC) family of serine/threonine kinases are thought to play critical roles in the regulation of cellular differentiation and proliferation in many cell types. An additional member of the PKC family was identified through human expressed sequence tag (EST) database search and its full length cDNA was isolated. Sequence analysis revealed that the predicted translation product was composed of 890 amino acid residues and that the protein has 77.3% similarity to human PKC mu (PKCmu) and 77. 4% similarity to mouse PKD (the mouse homolog of PKCmu). We designated the new member as protein kinase C nu (PKCnu). The PKCnu messenger RNA was ubiquitously expressed in various tissues when analyzed by Northern blots and reverse transcriptase-coupled polymerase chain reaction (PCR) analyses. The chromosomal location of the gene was determined between markers WI-9798 and D2S177 on chromosome 2p21 region by PCR-based methods with both a human/rodent monochromosomal hybrid cell panel and a radiation hybrid mapping panel.

Amino Acid Sequence↗
PubMed1999

The crystal structure of pyroglutamyl peptidase I from Bacillus amyloliquefaciens reveals a new structure for a cysteine protease.

BACKGROUND: The N-terminal pyroglutamyl (pGlu) residue of peptide hormones, such as thyrotropin-releasing hormone (TRH) and luteinizing hormone releasing hormone (LH-RH), confers resistance to proteolysis by conventional aminopeptidases. Specialized pyroglutamyl peptidases (PGPs) are able to cleave an N-terminal pyroglutamyl residue and thus control hormonal signals. Until now, no direct or homology-based three-dimensional structure was available for any PGP. RESULTS: The crystal structure of pyroglutamyl peptidase I (PGP-I) from Bacillus amyloliquefaciens has been determined to 1.6 A resolution. The crystallographic asymmetric unit of PGP-I is a tetramer of four identical monomers related by noncrystallographic 222 symmetry. The protein folds into an alpha/beta globular domain with a hydrophobic core consisting of a twisted beta sheet surrounded by five alpha helices. The structure allows the function of most of the conserved residues in the PGP-I family to be identified. The catalytic triad comprises Cys144, His168 and Glu81. CONCLUSIONS: The catalytic site does not have a conventional oxyanion hole, although Cys144, the sidechain of Arg91 and the dipole of an alpha helix could all stabilize a negative charge. The catalytic site has an S1 pocket lined with conserved hydrophobic residues to accommodate the pyroglutamyl residue. Aside from the S1 pocket, there is no clearly defined mainchain substrate-binding region, consistent with the lack of substrate specificity. Although the overall structure of PGP-I resembles some other alpha/beta twisted open-sheet structures, such as purine nucleoside phosphorylase and cutinase, there are important differences in the location and organization of the active-site residues. Thus, PGP-I belongs to a new family of cysteine proteases.

Amino Acid Sequence↗
PubMed1999

Human MD-1 homologue is a BCG-regulated gene product in monocytes: its identification by differential display.

BCG-CWS is a therapeutically potent immune activator which improves the prognosis of cancer patients. However, the targeting effector cells and molecules for BCG-CWS in the human immune system have not been determined. Here, we found that BCG-CWS activates human monocytes and concomitantly down-regulates expression of a human homologue of chicken MD-1 in the activated monocytes by differential display. According to a previous study, MD-1 forms a complex with the Toll family protein RP-105 on murine B cell lines to facilitate its stable expression. Thus, MD-1 may participate in regulation of innate immune activation on human monocytes. Our results, taken together with these recent findings regarding Toll family proteins, suggest that BCG-CWS acts on monocytes to modulate the human innate immune system via regulation of Toll family proteins.

Amino Acid Sequence↗
PubMed1999

Structure, expression profile and chromosomal location of an isolog of DNA-PKcs interacting protein (KIP) gene.

A novel DNA-PKcs interacting protein, KIP (kinase interacting protein), was recently isolated using a two-hybrid analysis which showed a significant homology to calcineurin B. We found other ESTs showing significant similarity to KIP gene in the dbEST database and isolated a cDNA clone which encodes a 187 amino acid polypeptide from a human fetal brain cDNA library. This protein (termed KIP2 for kinase interacting protein 2) has sequence homology to KIP (46% identical and 64% similarity). RT-PCR analysis showed that the messenger RNA was ubiquitously expressed in various human tissues. Based on PCR-based analysis with a radiation hybrid cell panel and fluorescence in situ hybridization, the gene was localized to the q24 region of chromosome 15.

Amino Acid Sequence↗
PubMed1999

Surgically induced degeneration and regeneration of the choriocapillaris in rabbit.

BACKGROUND: Retinal pigment epithelium (RPE) and choriocapillaris play an important role in maintaining the outer retina. Clinical and experimental studies have shown that there is a close relationship between them. To examine the relationship between RPE and choriocapillaris we developed an animal model in which degeneration and regeneration of the choriocapillaris can be created easily and reproducibly. METHODS: Using pigmented rabbits a retinal detachment (about 7 disk diameters) was created in the eye and the detached retina was surgically removed. A half area of the exposed RPE was mechanically debrided using a silicone brush. The other half area remained untouched. The eyes were morphologically examined at 3, 7, and 14 days and 4 and 8 weeks after the surgery using scanning or transmission electron microscopy. Changes in the choriocapillaris after the RPE debridement were also evaluated by corrosion vascular casts. RESULTS: The debrided area was resurfaced with elongated RPE in 7 days after surgery. The replaced RPE was dedifferentiated but it gradually recovered cell polarity by 4 weeks after surgery. The choriocapillaris beneath the debrided area underwent degeneration; however, it regenerated by 4 weeks after surgery, corresponding to the timing of the morphologic recovery of the replaced RPE. CONCLUSION: This animal model of surgically induced degeneration and regeneration of the choriocapillaris may be useful to clarify the relationship between RPE and choriocapillaris and to study potential treatments for choroidal vascular diseases.

Animals↗
PubMed1999

The human regulator of G-protein signaling protein 6 gene (RGS6) maps between markers WI-5202 and D14S277 on chromosome 14q24.3.

The recently discovered regulators of G-protein signaling proteins, termed the RGS family, have been shown to modulate the functioning of G-proteins by activating the intrinsic guanosine triphosphatase (GTPase) activity of the alpha subunits. Here, we report the chromosomal location and tissue expression of the human regulator of RGS6 gene. The messenger RNA was ubiquitously expressed in various tissues. Polymerase chain reaction (PCR)-based analysis with a human/rodent monochromosomal hybrid panel and a radiation hybrid panel indicated that the gene was mapped between genetic markers WI-5202 and D14S277 on chromosome 14q24.3 region.

Base Sequence↗
PubMed1999

Cloning, tissue expression, and chromosomal assignment of human MRJ gene for a member of the DNAJ protein family.

The DnaJ protein family consists of proteins with a highly conserved amino acid stretch called the "J-domain". A cDNA clone encoding a new protein with a J-domain was isolated from a human fetal brain cDNA library. This new member of the DnaJ family of 241 amino acid residues showed 94% identity with mouse Mrj (accession number, AF035962) and 71% identity with mouse Msj-1 (accession number, U95607) along its entire sequence. Reverse transcription-coupled polymerase chain reaction (RT-PCR) analysis showed the messenger RNA was ubiquitously expressed in various human tissues. The chromosomal location of the gene was determined by PCR-based analyses with both a human/rodent monochromosomal hybrid cell panel and a radiation hybrid panel to map on chromosome 11q25 region.

Amino Acid Sequence↗
PubMed1999

Prevention of visual field defect after macular hole surgery by passing air used for fluid-air exchange through water.

PURPOSE: To evaluate the effect on peripheral visual field defects occurring after macular hole surgery of passing air that is used for fluid-air exchange through water before infusion to the eye. METHODS: We used Goldmann perimetry to measure the visual fields of patients who underwent vitrectomy to manage idiopathic full-thickness macular holes using either room air or humidified air for fluid-air exchange. We retrospectively studied visual fields measured in 39 patients (group 1) who underwent vitrectomy without humidification of air and prospectively studied visual fields measured in 33 patients (group 2) who consecutively underwent vitrectomy with humidified air for fluid-air exchange. RESULTS: In group 1, nine patients (23%) had peripheral visual field defects, most often located in the inferior or inferotemporal quadrant. No patients (0%) in group 2 had a visual field defect after vitrectomy. The difference between groups 1 and 2 in the proportion of patients with visual field defects after vitrectomy was statistically significant (P = .003). CONCLUSIONS: Passing air used for fluid-air exchange through water seems to prevent visual field defects after vitrectomy for macular hole surgery. Visual field defects that occur after room air is used may result from desiccation of the retina by room air.

Aged↗