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Biomedical subjects

M Miyasaka

Publications and source records attributed to M Miyasaka.

At least 91 records · Page 5Linked to original sources
PubMed1998

A case of central carcinoma of the mandible arising from a recurrent odontogenic keratocyst: delineation of surgical margins and reconstruction with bilateral rectus abdominis myocutaneous free flaps.

A case of central carcinoma of the mandible arising from a recurrent odontogenic keratocyst is reported. A 38-year-old man was admitted to the Tokai University Hospital due to postoperative infection of a recurrent odontogenic keratocyst of the left mandible. He had had a cystectomy for an odontogenic keratocyst 4 years ago. The lesion revealed bony destruction of the mandible with worm-eating shaped margins with extension to the facial skin. A biopsy specimen revealed squamous cell carcinoma. The mandible was resected with facial skin and the sublingual space was dissected to preserve the lingual nerve. The oral and the facial resections were reconstructed with a titanium plate and bilateral rectus abdominis myocutaneous free flaps. The plate was removed due to infection around the margins and readjustment of the flaps was conducted 5 months after the surgery. He has not had a local relapse, metastasis, or incisional hernia for 8 months following surgery. Good occlusion has been attained by the residual mandible, and he is able to eat without any problems.

Adult↗
PubMed1997

A sulfatide receptor distinct from L-selectin is involved in lymphocyte activation.

Sulfatide induces leukocyte activation, which is thought to be mediated via L-selectin. Here we demonstrate that lymphocytes express a receptor for sulfatide distinct from L-selectin and that this receptor is involved in sulfatide-induced cell activation. While cell surface L-selectin expression was abolished by phorbol 12-myristate 13-acetate (PMA), lymphocytes retained the ability to bind sulfatide in liquid phase as well as in immobilized solid phase. The novel sulfatide receptor obtained from PMA-treated lymphocytes showed a molecular size of 65 kDa. Stimulation through this receptor triggered cytosolic free Ca2+ elevation and intercellular aggregation.

Animals↗
PubMed1997

Widespread expression of chondroitin sulfate-type serglycins with CD44 binding ability in hematopoietic cells.

Serglycin is a family of small proteoglycans with Ser-Gly dipeptide repeats and is modified with various types of glycosaminoglycan side chains. We previously demonstrated that chondroitin sulfate-modified serglycin is a novel ligand for CD44 involved in the adherence and activation of lymphoid cells. In this study, we investigated the production and distribution of CD44 binding serglycins in various hematopoietic cells and characterized their carbohydrate side chains. Immunoprecipitation analysis using CD44-IgG and polyclonal antibody against the serglycin core peptide demonstrated that various serglycin species capable of binding CD44 are produced by a variety of hematopoietic cells including lymphoid cells, myeloid cells, and a few tumor cell lines. Glycosaminoglycans on these serglycins, which are essential for CD44 binding, are composed of chondroitin 4-sulfate or a mixture of chondroitin 4-sulfate and chondroitin 6-sulfate, but no heparin or heparan sulfate side chain was detected. The serglycins are also secreted by normal splenocytes, lymph node lymphocytes, and bone marrow cells, whereas they are secreted in very small amounts by normal thymocytes. Secretion of serglycins is greatly enhanced by mitogenic stimulation with concanavalin A or lipopolysaccharide. Our results showed that serglycin, unlike hyaluronate, is produced and secreted in a functional (CD44 binding) form by many members of the hematopoietic system including various lymphocyte subsets. Our data suggest that serglycin may serve as a major ligand for CD44 in various events in the lymphohematopoietic system.

Animals↗
PubMed1997

Awareness of donor alloantigens in antiadhesion therapy induces antigen-specific unresponsiveness to islet allografts.

BACKGROUND: Antiadhesion therapy using monoclonal antibodies (mAbs) to adhesion molecules in vivo has been shown to produce significant prolongation of graft survival in various transplantation models. However, it remains unclear whether antiadhesion therapy operates by merely blocking adhesion between antigen-presenting cells and T cells physically and/or by blocking costimulatory signals while preserving signals mediated through T-cell receptors in vivo. We examined antigen-specific T-cell responses during and after antiadhesion therapy. METHODS: BALB/c islets were transplanted into the renal subcapsular space of streptozotocin-induced diabetic C57BL/6 mice given anti-lymphocyte function-associated antigen (LFA)-1 and/or anti-intercellular adhesion molecule-1 mAb treatment. The animals bearing surviving islet allografts were challenged with BALB/c or third-party islets on day 7 or more than 100 days after transplantation. RESULTS: Islet allografts were acutely rejected in untreated animals, with a mean survival time (MST) of 19+/-8 days. Administration of anti-LFA-1 mAb induced significant prolongation of graft survival with a mean survival time of 72+/-33 days, and half of the allografts showed indefinite survival. The animals given anti-LFA-1 mAb alone 7 days before transplantation showed acute rejection of BALB/c islets, whereas a significant number of animals given anti-LFA-1 mAb and the BALB/c islet allograft simultaneously accepted secondary BALB/c islets, but rejected third-party islets. Likewise, most of the animals bearing long-term functioning BALB/c allografts for more than 100 days accepted secondary BALB/c islets, but rejected C3H islets acutely. Interestingly, the spleen cells from these animals transferred unresponsiveness to BALB/c islets into the 2.5-Gy x-irradiated recipients, whereas those from naive animals induced acute rejection. CONCLUSIONS: These results indicate that anti-LFA-1 mAb treatment prevents T-cell activation leading to rejection, but results in a T-cell receptor engagement leading to antigen-specific unresponsiveness maintained by transferrable suppressor cells.

Animals↗
PubMed1997

Mouse homolog of poliovirus receptor-related gene 2 product, mPRR2, mediates homophilic cell aggregation.

Poliovirus receptor (PVR) is a cell surface glycoprotein that belongs to the immunoglobulin superfamily. Although MPH was initially reported as the mouse homolog of human PVR, recent data strongly suggest that MPH is the mouse homolog of human PRR2, a PVR-related gene 2 product, and not that of human PVR. Thus MPH is renamed mPRR2 in this study. Physiological functions of the PVR-related gene products have not been elucidated, although PVR has been well characterized as the poliovirus receptor. In this study, a possible function of mPRR2 (MPH), which is not a functional receptor for poliovirus, was investigated. Mouse L cells expressing mPRR2 were prepared. Those mouse cells showed a higher activity of cell aggregation than the parental mouse L cells. Enhancement of cell aggregation was also observed for insect Sf9 cells infected with recombinant baculovirus carrying mPRR2 cDNA. On the other hand, L cells expressing human PVR or monkey PVR (AGM alpha1 or AGM alpha2) did not show increased cell aggregation. The cell aggregation activity of L cells expressing mPRR2 was inhibited by the addition of anti-mPRR2 monoclonal antibodies or a soluble mPRR2 molecule produced by the baculovirus expression system. An immunofluorescence study revealed that mPRR2 protein was localized to the cell-cell contact sites between cells expressing mPRR2. A similar localization of mPRR2 was observed for intrinsic mPRR2 molecules of the mouse neuroblastoma cell line NS20Y. The contact site-specific localization of mPRR2 was not observed on the border between mPRR2-expressing and nonexpressing HeLa cells. Furthermore, mPRR2 proteins directly bound to each other in vitro. mPRR2 was detected on various types of cultured cells of mouse origin and in various mouse tissues. These results suggest that mPRR2 is an intercellular adhesion molecule with a homophilic binding manner.

Animals↗
PubMed1997

Analysis of expression of lymphocyte homing-related adhesion molecules in ALY mice deficient in lymph nodes and Peyer's patches.

The aly, alymphoplasia, is an autosomal recessive mutation in mice of an unknown etiology, which induces total aplasia of lymph nodes and Peyer's patches. We hypothesized that the lack of lymphoid tissue may be due to abnormalities of lymphocyte traffic into these tissues. Therefore, we analyzed the expression of various adhesion molecules associated with lymphocyte homing. Among the adhesion molecules examined, all were normally expressed except the mucosal addressin MAdCAM-1. In aly/aly mice MAdCAM-1 was absent in the spleen at mRNA and protein levels, but was normally expressed in the intestinal venules. The FISH analysis and linkage analysis using microsatellite markers demonstrated that the MAdCAM-1 gene is located on chromosome 10, indicating that MAdCAM-1 is not encoded by the aly gene, which is located on chromosome 11. Our results indicate that the aberrant expression of MAdCAM-1 is not the direct cause of aly mutation but rather a secondary defect.

Animals↗
PubMed1997

Role of a sialyl Lewis(x)-like epitope selectively expressed on vascular endothelial cells in local skin inflammation of the rat.

The role of the inducible L-selectin ligand was studied in complement-dependent acute dermatitis in rats. Although mAbs against typical sialyl Lewis(x) (CSLEX-1 and SNH-3) did not react with skin venules, a sialyl Lewis(x)-like epitope defined by mAb 2H5 (2H5-Ag) was de novo expressed on the endothelial cells of skin venules in the area of inflammation. Expression of 2H5-Ag increased concomitantly with the progression of inflammation. 2H5-Ag was identified at the 75-, 150-, and 180-kDa bands when inflammatory skin tissue was analyzed by Western blotting. In contrast, P- and E-selectins were not detectable. The role of 2H5-Ag in this model was studied in in vitro and in vivo methods. First, 2H5 was i.v. injected 15 min before induction of dermatitis. 2H5 bound to skin venules and significantly reduced the neutrophil infiltration and plasma protein leakage. In contrast, CSLEX-1, mAb ARP2-4 (P-selectin blocker), or mAb ARE-5 (E-selectin blocker) had no effects. Second, adhesion of isolated rat neutrophils to the inflammatory skin section was inhibited significantly when the sections, but not neutrophils, were preincubated with 2H5. Third, fluorescein-labeled normal rat neutrophils were injected into a rat 10 h after induction of dermatitis. The number of labeled neutrophils infiltrated into the inflammatory site was reduced significantly when they were preincubated with HRL-3 (blocking mAb against rat L-selectin), but not with 2H5 or HRL-4 (nonblocking mAb against rat L-selectin). These data show that de novo expressed 2H5-Ag/L-selectin adhesion pathway contributes to the development of acute complement-dependent inflammation in the skin.

Animals↗
PubMed1997

Selective inhibition of vascular cell adhesion molecule-1 expression by verapamil in human vascular endothelial cells.

Up-regulated expression of adhesion molecules on vascular endothelial cells (ECs) is an initial event in leukocyte adhesion to ECs, which is a crucial step in the process of inflammatory or immune reaction leading to organ transplant rejection. Verapamil and other calcium channel blockers have been reported to improve transplantation outcome and seem to possess immunosuppressive functions. Therefore, we tested the effect of verapamil on adhesion molecule expression of ECs and adherence of leukocytes to ECs. Verapamil was added to replicate human umbilical vein EC cultures, before adding cytokines. Protein and mRNA expression of E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 were measured by cell-ELISA and by Northern blot analysis after stimulation of ECs. Adherence of leukocytes to ECs was analyzed after stimulation of ECs by tumor necrosis factor-alpha, with pretreatment of verapamil. Verapamil selectively inhibited cytokine-induced protein and mRNA levels of VCAM-1, and suppressed cell adherence between tumor necrosis factor-alpha-stimulated ECs and mononuclear leukocytes or Molt-4 cells. These results suggest that verapamil may suppress immune response partly via inhibition of VCAM-1 expression on ECs and a certain subset of lymphocytes adherent to ECs.

Calcium Channel Blockers↗
PubMed1997

Genetic defect in T lymphocyte-specific homing into peripheral lymph nodes.

Lymphocytes circulating in the bloodstream home into lymph nodes (LN). T cells predominate in peripheral LN (PLN) and B cells in spleen or mucosal tissue, e.g. Peyer's patches (PP). DDD/1 mice are unique in marked paucity of LN cells, especially T cells. T cell frequency in PLN was 20-40% in this strain, compared to 60-80% in others. Immunohistochemistry confirmed the low density of T cells in the subcortical area but normal colonization of B cells in cortical area in PLN of DDD/1. In contrast, the T cell content of peripheral blood and spleen was higher in DDD/1 but that in PP was not significantly different compared to other strains. It was thus concluded that this abnormality in DDD/1 results from a homing defect of T cells into PLN but not from lymphopenia. Genetical analysis showed that the defect in T cell-specific homing was regulated by a single autosomal recessive gene, tentatively designated plt (paucity of lymph node T cells). Reciprocal bone marrow transplantation indicated that the plt phenotype may arise from some defect in PLN stroma but not in lymphocytes. An in vivo homing assay using fluorescence-labeled lymphocytes demonstrated that the homing defect was specific for T cells but not for B cells. A Stamper-Woodruff assay revealed that the binding between lymphocytes and PLN high endothelial venules was normal and that L-selectin and its ligand, peripheral node vascular addressin (PNAd), were expressed and functioned normally in DDD/1. These results taken together indicate that the T cell-specific homing into PLN is disturbed at a post-adhesion stage in DDD/1. The product of the plt locus may play a pivotal role at this stage.

Animals↗
PubMed1997

The expression patterns of standard and variant CD44 molecules in normal uterine cervix and cervical cancer.

CD44 is a cell-surface glycoprotein postulated to play a role in tumor-cell metastasis. We have examined the expression of the standard CD44 (CD44s), and alternative spliced variants of CD44 containing variant exons v6, v9, and v1O (CD44v6, CD44v9, and CD44v10 respectively) in 9 samples of normal cervix, 6 samples of cervical intraepithelial neoplasia (CIN), and 11 samples with invasive cervical carcinomas. RT/PCR demonstrated the presence of CD44s in all samples of normal cervix and those with invasive carcinomas. CD44v6 was also found in all normal cervical samples and in 9 tissue samples of invasive carcinomas. The results also suggested that some tumor specimens had several higher molecular transcripts containing exon v6 compared to specimens of normal cervix. Immunohistochemistry detected the presence of CD44s and the absence of CD44v10 in both epithelial and stromal cells in all specimens. In contrast, CD44v6 and CD44v9 were stained positive in epithelial cells but were absent in stromal cells. The intensity of CD44v6 and CD44v9 staining was strongest in normal cervical epithelium followed by CIN, invasive squamous cell carcinoma, and adenocarcinoma. In the malignant samples, heterogeneity in staining intensity among different clusters of tumor cells was observed. Furthermore, poorly differentiated and undifferentiated carcinomas from patients having poor prognosis did not stain at all. This study suggests that variant CD44 molecules may serve an important function in the cell contact of cervical epithelial cells, and that cervical epithelium acquires heterogeneity in the expression of CD44 adhesion molecules during carcinogenesis, which may be related to tumor metastasis.

Cervix Uteri↗
PubMed1997

Effect of anti-intercellular adhesion molecule-1 and anti-leukocyte function associated antigen-1 monoclonal antibodies on rat-to-mouse cardiac xenograft rejection.

BACKGROUND: The interaction between intercellular adhesion molecule-1 (ICAM-1) and its ligand, leukocyte function associated antigen-1 (LFA-1), is especially relevant in allograft rejection. We have previously shown that the simultaneous blockade of ICAM-1 and LFA-1 by monoclonal antibodies (mAbs) results in specific immunologic tolerance to cardiac allograft in a mouse model. METHODS: We evaluated the roles of these adhesion molecules in xenograft rejection by using a rat-to-mouse concordant xenograft model to identify critical molecules for immunosuppression. RESULTS: Lewis rat hearts transplanted into C3H/He mice were rejected within 5 to 7 days without treatment. A significant prolongation of xenograft survival (mean survival time, 11.6 days) was observed after treatment with anti-rat ICAM-1 and anti-mouse LFA-1 mAbs, when compared with nontreated mice or mice treated with different combinations of mAbs. Graft survival was prolonged in mice treated with FK506 (1 mg/kg/day), anti-rat ICAM-1, and anti-mouse LFA-1 mAbs (mean survival time, 22.2 days), whereas the same dose of FK506 alone was not effective. The mixed lymphocyte reaction showed that a combination of mAbs against mouse LFA-1-rat ICAM-1 and rat LFA-1-mouse ICAM-1 significantly inhibited the proliferation of mouse responders to rat stimulators and rat responders to mouse stimulators, respectively. Infiltration of mouse CD4 positive, mouse CD8 positive, and mouse LFA-1 positive cells, as well as dense deposition of mouse immunoglobulin G (IgG), IgM, and up-regulation of rat ICAM-1, on the graft endothelial cells were demonstrated by immunopathologic analysis of the rejected hearts. Flow cytometric analysis with rat spleen cells demonstrated the presence of xenoreactive antibodies (mouse IgG and IgM) in the recipient's serum. This xenoreactive antibody production was delayed but not inhibited by treatment of the recipients with anti-rat ICAM-1 and anti-mouse LFA-1. CONCLUSIONS: Blockade of the donor side ICAM-1 and the recipient side LFA-1 is critical for immunosuppression with anti-ICAM-1-LFA-1 treatment. Humoral factors may be responsible for xenograft rejection that occurs even after inhibition of the cell-mediated immune response by anti-ICAM-1 and anti-LFA-1 mAbs.

Animals↗
PubMed1997

Characterization of a 180 kDa molecule apparently reactive with recombinant L-selectin.

In the present study we identified a 180 kDa molecule (p180) in rat lymph nodes (LN) apparently reactive with silkworm derived recombinant L-selectin (LEC-IgG) in a Ca(2+)-dependent manner. Analysis of amino acid sequence revealed that p180 has a strong homology to the macrophage mannose receptor (MMR), which was corroborated by the observation that p180 reacted with polyclonal anti-alveolar MMR antibody and mannosyl-BSA-agarose. In agreement with this notion, the binding of p180 to the silkworm LEC-IgG was inhibited by alpha-methyl-D-mannoside. However, in sharp contrast to its reactivity against the silkworm LEC-IgG, p180 failed to bind LEC-IgG produced by COS-7 cells, suggesting that p180 reacted with the silkworm LEC-IgG through the recognition of oligomannose-type oligosaccharides expressed on the silkworm products and that the lectin activity of L-selectin was not involved in the interaction. These results, together with the immunohistochemical studies showing that p180 was absent from the majority of high endothelial venules (HEV) but present in medullary macrophages, led us to conclude that p180 obtained from LN lysates by the use of the silkworm LEC-IgG is not a physiological ligand for L-selectin, warning against the use of recombinant proteins expressed in the baculovirus/ silkworm expression system for the detection of carbohydrate ligands.

Amino Acid Sequence↗
PubMed1997

Induction of cell death by chimeric L-selectin-Fas receptors.

In the present study, we have established a system where engagement of an adhesion molecule triggers a death signal into cells. L-selectin, which is a well characterized adhesion receptor involved in the initial adhesion between lymphocyte and endothelium, was fused to the intracellular domain of an apoptosis-inducing molecule, Fas. Ligation of the chimeric receptors with a carbohydrate ligand for L-selectin, fucoidin or a mAb that recognizes the lectin domain of L-selectin, induced apoptosis in receptor-expressing cells. However, ligation with an anti-L-selectin mAb reactive with a non-ligand binding site did not induce apoptosis, indicating that stimulation through the lectin domain of L-selectin in the chimeric receptor leads to signal delivery. Upon activation L-selectin shows a unique proteolytic cleavage at the membrane proximal site on the extracellular (EC) domain, of which the significance is also unclear. We found that truncations in the EC domain which abrogate the proteolytic cleavage of L-selectin did not influence induction of apoptosis, suggesting that the cleavage on the EC domain itself is not important for the signaling function of the chimeric receptor. This is the first demonstration that an adhesion signal can be converted to a signal that leads to apoptotic cell death.

Animals↗
PubMed1997

The influence of different types of hard-palate closure in two-stage palatoplasty on maxillary growth: cephalometric analyses and long-term follow-up.

Using cephalometric analysis we investigated the influence on maxillary growth of two different types of hard-palate closure in two-stage palatoplasty. In 12 patients with complete unilateral cleft lip, alveolus, and palate, the lip and soft-palate were closed between 3 and 7 months of age. These 12 patients were then assigned to two groups of 6. In one group the hard palate was closed at 1 year 5 to 11 months of age by a vomer flap with a skin graft (VF group, Osada's two-stage palatoplasty) and in the other group it was closed by the mucoperiosteal pushback procedure (PB group). Sella-nasion-point A (SNA) in the VF group at 3 to 4 and after 10 years of age were within normal range and significantly larger than in the PB group. Two patients in the PB group required orthognatic surgery to obtain normal occlusion and a well-balanced profile. We concluded that in two-stage palatoplasty better maxillary growth can be obtained using the vomer flap method than using the pushback procedure.

Adolescent↗