Biomedical subjects

K Kuribayashi

Publications and source records attributed to K Kuribayashi.

At least 37 records · Page 2Linked to original sources

PubMed1999

The absence of interleukin 1 receptor-related T1/ST2 does not affect T helper cell type 2 development and its effector function.

T1/ST2, an orphan receptor with homology with the interleukin (IL)-1 receptor family, is expressed constitutively and stably on the surface of T helper type 2 (Th2) cells, but not on Th1 cells. T1/ST2 is also expressed on mast cells, which are critical for Th2-mediated effector responses. To evaluate whether T1/ST2 is required for Th2 responses and mast cell function, we have generated T1/ST2-deficient (T1/ST2(-/-)) mice and examined the roles of T1/ST2. Naive CD4(+) T cells isolated from T1/ST2(-/-) mice developed to Th2 cells in response to IL-4 in vitro. T1/ST2(-/-) mice showed normal Th2 responses after infection with the helminthic parasite Nippostrongylus brasiliensis as well as in the mouse model of allergen-induced airway inflammation. In addition, differentiation and function of bone marrow-derived cultured mast cells were unaffected. These findings demonstrate that T1/ST2 does not play an essential role in development and function of Th2 cells and mast cells.

Animals↗

PubMed1999

A single immunization with a plasmid encoding hepatitis C virus (HCV) structural proteins under the elongation factor 1-alpha promoter elicits HCV-specific cytotoxic T-lymphocytes (CTL).

Recent studies have raised the possibility that DNA-based vaccination may prove useful for generating virus-specific cytotoxic T-lymphocytes (CTL) responses. Recently, a plasmid containing the human elongation factor 1alpha(EF1-alpha) promoter, pEF321, was reported to be a versatile expression vector for gene expression in mammalian cells in vitro. In the present study, we assessed the capability of a novel plasmid, pEFCE1E2, encoding hepatitis C virus (HCV) structural proteins (core, E1 and E2) under the EF1-alpha promoter to generate CTL against HCV in vivo. BALB/c mice were immunized with the pEFCE1E2 but not with a plasmid possessing the same cDNA under the cytomegalovirus developed HCV-specific effector cells by a single immunization. These effector cells elicited by pEFCE1E2 immunization were CD8(+) and major histocompatibility complex class I restricted. These studies provided evidence for the potential utility of the EF1-alpha promoter for development of DNA vaccines against HCV infections.

Amino Acid Sequence↗

PubMed1999

Cyclic mechanical stretch stress increases the growth rate and collagen synthesis of nucleus pulposus cells in vitro.

STUDY DESIGN: A rabbit model designed to investigate the effects of applied cyclic tensile stress on the cell division rate and the collagen synthesis in the rabbit nucleus pulposus cells in vitro. OBJECTIVE: To evaluate the effects of mechanical stress on nucleus pulposus cells, thus adding to the understanding of the adaptation of the intervertebral disc to mechanical stress. SUMMARY OF BACKGROUND DATA: Intervertebral disc cells in vivo are exposed to a multitude of physical forces during physical motion. Although it is known that in intervertebral disc disease, a common pathway of disc degeneration is mechanical stress on the nucleus pulposus or the anulus fibrosus or both, the underlying mechanism has been less well defined. METHODS: Nucleus pulposus cells were isolated from 4-week-old Japanese white rabbits. These cells were subjected to the mechanical cyclic stretch stress using a computerized, pressure-operated instrument that physically deformed the cells. The DNA synthesis rate, collagen synthesis rate, and cell cycle progression were measured. RESULTS: Cyclic tensile stretch increased the DNA synthesis rate in nucleus pulposus cells and in the population of cells in the S phase of the cell cycle during 1 to 2 days of subjugation to stress. Cyclic tensile stretch also increased collagenous protein synthesis in nucleus pulposus cells during 1 to 4 days of stress. CONCLUSIONS: Mechanical stress on nucleus pulposus cells promotes the proliferation of cells and alters the properties of intervertebral disc cells. This study may reflect the adaptation of the intervertebral disc to increased motion and stress.

Adaptation, Physiological↗

PubMed1999

Effects of sintered bovine bone on cell proliferation, collagen synthesis, and osteoblastic expression in MC3T3-E1 osteoblast-like cells.

To determine the function of biomaterials on osteoblasts, we studied the effects of two different biomaterials, sintered bovine bone (true bone ceramic) and hydroxyapatite-related material, on DNA and collagen synthesis and osteoblastic expression in osteoblast-like cells in vitro. Osteoblasts cultured with true bone ceramic exhibited greater increases in DNA and collagenous protein synthesis and alkaline phosphatase activity than those cultured with hydroxyapatite. Furthermore, expression of mRNA for type-I collagen and osteocalcin, as assessed by reverse transcription-polymerase chain reaction, was higher in cultures grown on true bone ceramic or hydroxyapatite than in those grown with glass fragments, and levels of gene expression in true bone ceramic and hydroxyapatite cultures were at almost the same level. These findings indicate that osteoblasts cultured with true bone ceramic increase their activity, suggesting that true bone ceramic may be a more favorable substrate than hydroxyapatite for growth and differentiation of osteoblast-like cells.

Alkaline Phosphatase↗

PubMed1999

mRNA expression of interleukins, phospholipase A2, and nitric oxide synthase in the nerve root and dorsal root ganglion induced by autologous nucleus pulposus in the rat.

The purpose of this study was to examine whether mRNA of interleukin-A2, interleukin-6, phospholipase A2, and nitric oxide synthase was expressed in the nerve root and dorsal root ganglion of an animal model in which exposure to the nucleus pulposus induced mechanical hyperalgesia, a pain-related behavior. Autologous nucleus pulposus obtained from coccygeal discs was relocated on the L4 and L5 lumbar nerve roots after partial laminectomy. The reflex response to noxious mechanical stimuli to the hindpaw was measured preoperatively and to 4 weeks postoperatively. With a reverse transcription-polymerase chain reaction technique, expression of interleukin-1beta, interleukin-6, phospholipase A2, and inducible nitric oxide synthase genes in the nerve root and dorsal root ganglion was observed at 1, 2, and 4 weeks postoperatively. Mechanical hyperalgesia was observed from 3 days to 2 weeks postoperatively. The expression of interleukin-1beta, phospholipase A2, and inducible nitric oxide synthase mRNAs increased after only 1 week. This increase was related to mechanical hyperalgesia. Expression of interleukin-6 was detected in the neural tissue over time. It is possible that interleukin-1beta, phospholipase A2, and inducible nitric oxide in the nerve root or dorsal root ganglion, or in both, produce sciatic pain in the early stage of herniation of the lumbar disc.

Animals↗

PubMed1999

Cytoprotective effect of ulinastatin, a Kunitz-type protease inhibitor, on hypoxic injury in L2 cells treated with antimycin A via stabilization of lysosomal fragility.

The cytoprotective effect of ulinastatin, a Kunitz-type protease inhibitor, was studied in L2 cells treated with antimycin A, which induces depletion of cellular adenosine triphosphate (ATP), so-called < >. Antimycin A treatment with 2 microM significantly elevated the release of N-acetyl-beta-D-glucosaminidase (NAG), a lysosomal enzyme, to 51.99+/-7.36%. In this condition, ulinastatin tended to inhibit the release of NAG at a concentration of 1000 U/ml (39.74+/-3.80%) and significantly ameliorated it at a concentration of 3000 U/ml (32.35+/-4.17%). Furthermore, ulinastatin at 10 U/ml showed a suppression on the fragility of lysosomal membrane isolated from L2 cells. These results indicate that ulinastatin has a prominent protective effect on hypoxic injury in L2 cells, and the lysosomal stabilizing effect is possibly involved as a mechanism of this action.

Acetylglucosaminidase↗

PubMed1999

Enhanced inhibition of experimental metastasis by the combination chemotherapy of Cu-Zn SOD and adriamycin.

We previously reported that reactive oxygen species (ROS) enhance tumor cell metastasis, and by administration of recombinant human superoxide dismutase (rh SOD), an enzyme which scavenges O2- successfully reduced lung metastasis of mouse MethA sarcoma and Lewis lung carcinoma. These observations suggested that rh SOD suppressed tumor cell invasion by eliminating O2- the primary source of ROS. However, for the clinical application of the drug as an anti metastatic agent, rh SOD needs to be administered in combination with other cytotoxic agents, since SOD by itself has no cytotoxic activity. In this paper, we investigated the effectiveness of the combination chemotherapy of rh SOD and adriamycin (ADR), an anti-cancer agent against the experimental metastasis of highly metastatic clone, MH-02, which was derived from murine Meth A sarcoma. The present metastasis experiment clearly indicates that the administration of rh SOD enhances the antimetastatic effect of ADR. On the other hand, we found that the inhibition rate of metastasis exhibited by the combination chemotherapy of rh SOD and a certain dose (5 mg/ml) of ADR was inferior to that of rh SOD. This apparent paradoxical phenomenon was presumably explained by our finding that tumor cells themselves augment their invasive capacity and platelet aggregation, both of which are causative factors for metastasis formation, by generation of O2- when they were treated with ADR. Nevertheless, the combination chemotherapy of SOD with anticancer drugs such as ADR can be a practical anti-metastasis strategy.

Animals↗

PubMed1999

STAT6 deficiency in a mouse model of allergen-induced airways inflammation abolishes eosinophilia but induces infiltration of CD8+ T cells.

BACKGROUND: The TH2-type cytokines have been reported to contribute to the asthmatic response. STAT6 has an essential role in IL-4 signalling and in production of TH2 cytokines from T cells and is involved in IgE and IgG1 responses after nematode infections, indicating that STAT6 has an important role in allergic diseases. OBJECTIVE: In this study we investigated the effects of STAT6 deficiency on allergen-induced airways inflammation in mice. METHODS: Both ovalbumin (OVA)-sensitized STAT6 deficient (STAT6-/-) mice and wild-type C57BL/6 mice were challenged with aerosolized OVA. Changes in inflammatory cell infiltration and cytokine levels in lung tissue as well as serum immunoglobulin levels were analysed in OVA-challenged STAT6-/- and wild-type mice. RESULTS: The eosinophilia and lung damage normally resulting from aeroallergen challenge were not seen in STAT6-/- mice. Expression of TH2 cytokines (IL-4 and IL-5) in the lung tissue as well as IgE and IgG1 responses after OVA challenge were profoundly reduced in STAT6-/- mice, whereas expression of IFNgamma was the same in STAT6-/- mice and wild-type mice after OVA challenge. Immunocytochemical analysis of T cells showed the infiltration of CD4+ T cells but not CD8+ T cells increased into the lung of wild-type mice after OVA challenge. However, the OVA-exposed STAT6-/- mice demonstrated the infiltration of both CD4+ T cells and CD8+ T cells with a significant increase in percentage and total number of CD8+ T cells compared with OVA-exposed wild-type mice. CONCLUSION: These results indicate that factors which signal through STAT6 are important regulators of eosinophilia of allergic airway inflammation, regulating TH2-type cytokine production both in CD4+ T cells and CD8+ T cells.

Allergens↗

PubMed1999

RNA editing-like phenomenon in paramyxovirus V gene mRNA observed in insect cells infected with a recombinant baculovirus.

The V gene of the paramyxovirus human parainfluenza virus type 2 (hPIV2) is transcribed into both V and P mRNA. The V mRNA is a faithful transcript of the V gene; however, the P mRNA is transcribed by an RNA-editing mechanism in hPIV2-infected mammalian cells. Recombinant baculoviruses (rBV) were constructed containing the wild-type V gene, which has seven G residues at its editing site, and a manipulated V gene with ten G residues at its editing site. A small amount of the P protein was synthesized, in addition to the V protein, when the wild-type V gene was expressed in rBV-infected insect cells. Furthermore, synthesis of the P protein increased when rBV containing the manipulated V gene was used to infect insect cells. Both the P and V proteins were detected after in vitro translation of mRNA from rBV-infected cells. Moreover, G-residue insertions and a deletion were detected in mRNA. Since the P protein was not detected after in vitro translation of V RNA that had been transcribed in vitro by T7 RNA polymerase, these results suggest that the non-encoded G residues were inserted and deleted during transcription in insect cells. This RNA editing-like phenomenon and the implications of the length of the G cluster are discussed.

Animals↗

PubMed1999

Helper T cell determinant peptide contributes to induction of cellular immune responses by peptide vaccines against hepatitis C virus.

The capacity of novel subunit vaccines to generate cytotoxic T lymphocytes (CTLs) against hepatitis C virus (HCV) was assessed. BALB/c mice were immunized with peptides based on the CTL and helper T cell (Th) epitopes of the HCV core, with a mixture of CTL and Th peptides (CTL+Th) or with a conjugated Th-CTL peptide. Mice immunized with CTL, CTL+Th and Th-CTL peptides, but not those immunized with Th peptide, developed HCV core CTL epitope-specific effector cells. Cytotoxic activity induced by immunization with Th-CTL was much higher than that induced by immunization with CTL+Th or CTL alone. However, rapid and high cytotoxic activities against HCV core were not only detected after immunization with peptides containing the CTL epitope but also as a result of infection with recombinant vaccinia virus carrying the HCV core gene after immunization with the Th epitope alone. Immunization with peptides containing the Th epitope also elicited spleen cell proliferation. This study demonstrates the capacity of both Th and CTL activated peptide vaccines to elicit CD8+, MHC class I-restricted CTLs. The capacity of such CTLs to contribute towards a protective and/or pathogenic immune response against HCV can now be assessed in mouse models.

Amino Acid Sequence↗

PubMed1999

Bone marrow-derived dendritic cells incorporate and process hydrophobized polysaccharide/oncoprotein complex as antigen presenting cells.

We have previously shown that a novel hydrophobized polysaccharide/oncoprotein complex vaccine can induce immune responses against the HER2/neu/c-erbB2 (HER2) expressing tumors. Bone marrow-derived dendritic cells (DCs), as antigen presenting cells (APCs), are the first candidates for presentation of tumor antigens. The aim of this study was to see whether DCs are able to elicit antigen specific host immune responses by stimulating the proliferation of T cells after exposure to cholesteryl group bearing pullulan (CHP) and HER2 protein complex. Vaccination by CHP-HER2 complex was as effective as cholesteryl group bearing mannan (CHM) and HER2 complex on which we reported previously. Immunization of mice with HER2 expressing CMS17HE tumor cells generated both CD4+ T cells and CD8+ T cells reactive with CHP-HER2 complex pretreated DCs. In addition, immunization with either CHP-HER2 complex or HER2 protein alone could also generate both CD4+ T cells and CD8+ T cells specifically reactive with CHP-HER2 complex pretreated DCs. The complete rejection of tumors occurred when immunization with CHP-HER2 complex pretreated DCs was started 10 days after tumor inoculation. Therefore, bone marrow-derived DCs pretreated with hydrophobized polysaccharide/oncoprotein complex are a powerful tool for enhancing the effectiveness of oncoprotein for anti-tumor vaccination, opening new options for immune cell therapy.

Animals↗

PubMed1999

[Pleural malignant mesothelioma complicated by multiple myeloma].

A 79-year-old woman was admitted because of dyspnea. Chest X-ray films and computed tomographic scans disclosed left pleural effusion and diffuse pleural thickening. A diagnosis of multiple myeloma was made on the basis of blood tests and bone marrow aspiration biopsy findings. Multiple myeloma was the suspected cause of the pleural lesions. However, a postmortem diagnosis of malignant mesothelioma of the pleura was made on the basis of histological and immunohistological studies of autopsy specimens.

Aged↗

PubMed1999

[Waldenström macroglobulinemia with diffuse large B-cell lymphoma that developed from a different B-cell clone].

A 62-year-old man was given a diagnosis of Waldenström macroglobulinemia (WM) in January 1995. He was treated with melphalan and corticosteroid until January 1996, when he experienced high fever and weight loss. The patient visited a nearby hospital, received a diagnosis of liver abscess, and was referred to our hospital on February 23, 1996. Computed axial tomographic scans demonstrated multiple isodensity masses in the liver, left adrenal region, and right kidney hilum. Needle biopsy specimens of a liver mass revealed infiltration of diffuse large B-cell lymphoma (REAL classification), suggesting that non-Hodgkin's lymphoma supervened WM. Despite multiple cycles of chemotherapy, the lymphoma responded poorly. The patient died of pneumonia and sepsis on May 10, 1996 and an autopsy disclosed broad involvement of liver and spleen with lymphoma. Southern blot analysis of DNA samples obtained from the patient's bone marrow at the time of the initial diagnosis of WM, and later from the needle biopsy specimen of liver mass, displayed different patterns of immunoglobulin heavy chain gene rearrangement. We therefore concluded that in this patient the lymphoma was not a progression of WM, but rather, an independent B-cell malignancy.

B-Lymphocytes↗

PubMed1998

A novel hydrophobized polysaccharide/oncoprotein complex vaccine induces in vitro and in vivo cellular and humoral immune responses against HER2-expressing murine sarcomas.

To elicit specific cellular immune responses against cancer, the development of efficient devices to deliver tumor antigen peptides to the MHC class I pathway constitutes a central issue. We report here a novel formula of hydrophobized polysaccharide nanoparticles, which can deliver a HER2 oncoprotein containing an epitope peptide to the MHC class I pathway. A protein consisting of the 147 amino-terminal amino acids of oncogene erbB-2/neu/HER2 (HER2) was complexed with two kinds of hydrophobized polysaccharides, cholesteryl group-bearing mannan (CHM) and cholesteryl group-bearing pullulan (CHP), to form nanoparticles (CHM-HER2 and CHP-HER2). CHM-HER2 and CHP-HER2 were able to induce CD3+/CD8+ CTLs against HER2-transfected syngeneic fibrosarcoma cell lines. In contrast, the oncoprotein alone failed to do so. These CTLs were Kd-restricted and specifically recognized a peptide (position 63-71) that was a part of a truncated HER2 protein used as an immunogen. In addition, vaccination by CHM-HER2 complexes led to a strongly enhanced production of IgG antibodies against HER2, whereas vaccination with HER2 proteins alone resulted in a production of antibodies at a marginal level. Mice immunized with CHM-HER2 or CHP-HER2 before tumor challenge successfully rejected HER2-transfected tumors. The complete rejection of tumors also occurred when CHM-HER2 was applied not later than 3 days after tumor implantation. In the effector phase of in vivo tumor rejection, CD8+ T cells played a major role. The results suggest that a sort of hydrophobized polysaccharide may help soluble proteins to induce cellular immunity as well enhance humoral immunity; hence, such a novel vaccine may be of potential benefit to cancer prevention and cancer therapy.

Animals↗

PubMed1998

p53-independent induction of WAF1/Cip1 is correlated with osteoblastic differentiation by vitamin D3.

1Alpha,25(OH)2 vitamin D3 (1,25(OH)2D3) can induce differentiation of osteoblastic cells by arresting the cell cycle at G1. The p53-inducible gene, WAF1/Cip1, is one of the inhibitors of cyclin-dependent kinases and can inhibit the phosphorylation of retinoblastoma protein (pRB), thereby keeping pRB functionally active. Here we show that in a p53-null human osteoblastic osteosarcoma MG-63 cell line, 10 nM of 1,25(OH)2D3 completely inhibits cell growth and increases alkaline phosphatase activity, which suggests the induction of osteoblastic differentiation. We also found a p53-independent increase of WAF1/Cip1 mRNA and promoter activation by 1,25(OH)2D3. On the other hand, the expression and the promoter activity of the RB gene decreased after treatment with 1,25(OH)2D3 during the differentiation of MG-63 cells. Our results suggest that the p53-independent WAF1/Cip1 induction by 1,25(OH)2D3 is important for osteoblastic differentiation of MG-63 cells.

Calcitriol↗

PubMed1998

Overlapping epitopes of friend murine leukemia virus gag-encoded leader sequence recognized by single cytotoxic T-lymphocyte clones.

The leader signal sequence of the non-structural gag-encoded glycoprotein precursor, Pr75gag, of Friend murine leukemia virus (F-MuLV) contains overlapping epitopes, SIVLCCLCL (p71-79) and CCLCLTVFL (p75 83) that activate Friend virus (FV)-induced tumor (FBL-3)-specific cytotoxic T-lymphocytes (CTL) (Kondo et al., J. Virol., 69, 1995, 6735-6741; Chen et al., J. Virol., 70, 1996, 7773-7782). It was investigated whether these two peptides are recognized by a single CTL clone or by individual clones with different specificities. The results show that both hydrophobic and cysteine-containing peptides are bound to H-2Db class I major histocompatibility complex (MHC) molecules and cross-recognized by a single CTL clone as well as bulk-cultured CTL from the spleens of mice immunized with FBL-3. The peptide p71-79 was effective for sensitizing target cells to lysis by CTL in the concentration of common antigenic peptides. Moreover, peptide p75-83 was 1000-fold more potent than the peptide p71-79. Specific cytotoxicity assays with variant peptides with alanine- and serine-substitutions suggested a highly complex function of the disulfide bond-forming peptides potentially sensitive to small sequence differences. The dominance of CTL responses to the transmembrane region is discussed in light of the high affinity of a novel hydrophobic peptide to compete with other peptides for binding to MHC molecules.

Amino Acid Sequence↗

PubMed1998

Induction of cross-reactivity in an endogenous viral peptide non-reactive to FBL-3 tumor-specific helper T-cell clones.

We previously reported a helper T-cell (Th) epitope (peptide i) which corresponded to the sequence ranging from positions 462 to 479 from the N-terminus of the Friend-murine leukemia virus (F-MuLV) envelope protein (env462-479). Homologous sequences exist in both Moloney-murine leukemia (M-MuLV env452-469) and endogenous AKV (AKV env453-470) viruses, which differ from F-MuLV env462-479 in 5 and 7 amino acids, respectively. However, peptide i-specific Th clones did not respond to either of the corresponding exogenous or endogenous peptides. One amino acid substitution in M-MuLV env452-469 (Asn to Tyr at position 465: N465Y) and three amino acids in AKV env453-470 (H460S, A466Y and Y468H) endowed both peptides with the reactivity to one of the Th clones, F5-5, almost to the same degree as peptide i. However, the other Th clones responded differently to each of the modified endogenous peptides substituted by one to three amino acids. The cells responsive to the cross-reactive peptides occupied only a minor portion, if any, of the bulk cultured lymph node cells from peptide i-immune mice, and in particular, no significant response to the modified endogenous peptides was observed in repeated experiments. The exchange of at least 3 residues was necessary for the endogenous peptide to acquire sufficient cross-reactivity to two of the three Th clones. However, it was noticeable that a single substitution of alanine by tyrosine at the dominant T-cell receptor (TCR) contact position of the peptide i(e) generated a weak but significant cross-reactivity to one of the three Th clones in this study. Thus, peptides of endogenous retroviral origin that would be modified by mutational events might become 'non-self' and prime Th cells leading to auto-antibody production and resulting in autoimmune disease.

Amino Acid Sequence↗

PubMed1998

Two cases of eosinophilic gastroenteritis associated with analgesic-induced bronchial asthma.

Two patients (one male and one female) with bronchial asthma were diagnosed as having eosinophilic gastroenteritis (EG). The condition was revealed by biopsies through fibrescopic endoscopy. According to the Klein classification, they had mucosal disease. The symptoms were abdominal pain and nausea. The symptoms subsided with corticosteroid administration in one patient and with palliative treatment in the other patient. It was suggested that fibrescopic endoscopy biopsy is needed to identify coexisting EG if a bronchial asthma patient complains of severe gastrointestinal symptoms.

Adult↗