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Biomedical subjects

S Kawamoto

Publications and source records attributed to S Kawamoto.

At least 73 records · Page 4Linked to original sources
PubMed2000

Semaphorin3A enhances endocytosis at sites of receptor-F-actin colocalization during growth cone collapse.

Axonal growth cone collapse is accompanied by a reduction in filopodial F-actin. We demonstrate here that semaphorin 3A (Sema3A) induces a coordinated rearrangement of Sema3A receptors and F-actin during growth cone collapse. Differential interference contrast microscopy reveals that some sites of Sema3A-induced F-actin reorganization correlate with discrete vacuoles, structures involved in endocytosis. Endocytosis of FITC-dextran by the growth cone is enhanced during Sema3A treatment, and sites of dextran accumulation colocalize with actin-rich vacuoles and ridges of membrane. Furthermore, the Sema3A receptor proteins, neuropilin-1 and plexin, and the Sema3A signaling molecule, rac1, also reorganize to vacuoles and membrane ridges after Sema3A treatment. These data support a model whereby Sema3A stimulates endocytosis by focal and coordinated rearrangement of receptor and cytoskeletal elements. Dextran accumulation is also increased in retinal ganglion cell (RGC) growth cones, in response to ephrin A5, and in RGC and DRG growth cones, in response to myelin and phorbol-ester. Therefore, enhanced endocytosis may be a general principle of physiologic growth cone collapse. We suggest that growth cone collapse is mediated by both actin filament rearrangements and alterations in membrane dynamics.

Actins↗
PubMed2000

T-cell epitope analysis of Mag 3, an important allergen from the house dust mite, Dermatophagoides farinae.

Here we describe the detection of T-cell epitope region on the house dust mite allergen Mag 3, which has been shown to trigger T-cell proliferation in mite-allergic asthmatic patients. We first examined murine T-cell epitope using T-cell fraction prepared from recombinant Mag 3 (r-Mag 3)-primed H-2k mice. Initial proliferation assay with truncated r-Mag 3 indicated that N-terminal 113 amino acid region was required for triggering T-cell activation. Subsequent epitope scanning with synthetic overlapping peptides revealed that T-cell reactive region was assigned within amino acid range 56-75. We also explored human T-cell determinant using specific T-cells from mite-allergic patients. Intriguingly, we found that amino acid range 56-85, a portion partially overlapping with that identified in r-Mag 3-primed mice, was exclusively recognized by T-cells from different patients. Further investigation of unique T-cell epitope region found in this study would provide insight into the development of animal therapeutic model and/or peptide vaccine for asthma.

Allergens↗
PubMed2000

In vivo gene gun-mediated DNA delivery into rodent brain tissue.

Various types of gene transfer into live tissues have been tried. However, in vivo gene transfer into brain tissue or neuronal cells without virus vector has required a great effort. Particle-mediated gene transfer into live brain tissue was thought to be impossible because of its fragility and the mechanical problem of a previous type of gene gun. In addition, particle-mediated DNA transfer into monolayer-cultured cells without mechanical damage has been difficult. We successfully transferred DNA into rodent live brain tissue and also into monolayer-cultured cells without mechanical damage by using a new type of gene gun and also confirmed gene expression in the brain. This new method represents another variation of gene transfer into the brain.

Animals↗
PubMed2000

A novel reporter mouse strain that expresses enhanced green fluorescent protein upon Cre-mediated recombination.

The success of Cre-mediated conditional gene targeting depends on the specificity of Cre recombinase expression in Cre-transgenic mouse lines. As a tool to evaluate the specificity of Cre expression, we developed a reporter transgenic mouse strain that expresses enhanced green fluorescent protein (EGFP) upon Cre-mediated recombination. We demonstrate that the progeny resulting from a cross between this reporter strain and a transgenic strain expressing Cre in zygotes show ubiquitous EGFP fluorescence. This reporter strain should be useful to monitor the Cre expression directed by various promoters in transgenic mice, including mice in which Cre is expressed transiently during embryogenesis under a developmentally regulated promoter.

Alleles↗
PubMed2000

The timing of GM-CSF expression plasmid administration influences the Th1/Th2 response induced by an HIV-1-specific DNA vaccine.

The mechanism of immune activation induced by a plasmid-encoding GM-CSF (pGM-CSF), administered in combination with a DNA vaccine encoding the envelope of HIV, was studied. Injecting pGM-CSF i.m. into mice 3 days before DNA vaccination primarily induced a Th2 response. Simultaneous administration of the DNA vaccine plus pGM-CSF activated both a Th1 and a Th2 response. When the plasmid was injected 3 days after DNA vaccination, enhancement of Th1 immunity predominated. These results suggest that the timing of cytokine expression determines the phenotype of the resultant Th response. After 3 days of pGM-CSF injection, the increased percentages of CD11c+, CD8+ cells were observed in the regional lymph nodes. In addition, many infiltrated cells, including S-100 protein-positive cells, were found in the pGM-CSF-injected tissue. The importance of these S-100+ cells or both CD8+ and CD11c+ cells, especially that of dendritic cells (DCs), was also studied. DCs derived from bone marrow and cultured in RPMI 1640 medium containing IL-4 and GM-CSF were incubated with DNA vaccine and then transferred into naive mice. Mice receiving DCs showed strong HIV-1-specific Th2 immune responses. Our results suggest that DCs play important roles in the activation or modification of the Th2-type immune response induced by DNA vaccination.

AIDS Vaccines↗
PubMed2000

Rectal and vaginal immunization with a macromolecular multicomponent peptide vaccine candidate for HIV-1 infection induces HIV-specific protective immune responses.

An effective vaccine for human immunodeficiency virus (HIV) is needed to stimulate the immune response of the genital mucus to prevent mucosal transmission of the virus. We have developed a macromolecular multicomponent peptide vaccine candidate, VC1. Both rectal and vaginal immunization of VC1 mixed with cholera toxin (CT) induced HIV-1-specific IgA antibody in mouse fecal extract solution and vaginal wash. These antibody productions were enhanced by the combination with IL-4 or GM-CSF expressing plasmids. Either fecal extract or vaginal wash solution from immunized mice inhibited production of HIV-1IIIB p24 protein. The mononuclear cells from spleen, intestinal lymph nodes, or Peyer's patches from VC1- and CT-immunized mice released IFN-gamma or IL-4, when these cells were co-cultured with VC1 antigen. In addition, the regional lymphoid cells from rectal and vaginal region of mice immunized with VC1 and CT also elicited a substantial level of HIV-1-specific cytotoxic T cell (CTL) response. This CTL response was enhanced by the addition of IL-12 expressing plasmid. Our results clearly demonstrated that both rectal and vaginal immunization could induce systemic and mucosal immunities specific for HIV-1.

AIDS Vaccines↗
PubMed2000

BodyMap: a human and mouse gene expression database.

BodyMap is a human and mouse gene expression database that has been maintained since 1993. It is based on site-directed 3'-ESTs collected from non-biased cDNA libraries constructed at Osaka University and contains >270 000 sequences from 60 human and 38 mouse tissues. The site-directed nature of the sequence tags allows unequivocal grouping of tags representing the same transcript and provides abundance information for each transcript in different parts of the body. Our collection of ESTs was compared periodically with other public databases for cross referencing. The histological resolution of source tissues and unique cloning strategy that minimized cloning bias enabled BodyMap to support three unique mRNA based experiments in silico. First, the recurrence information for clones in each library provides a rough estimate of the mRNA composition of each source tissue. Second, a user can search the entire data set with nucleotide sequences or keywords to assess expression patterns of particular genes. Third, and most important, BodyMap allows a user to select genes that have a desired expression pattern in humans and mice. BodyMap is accessible through the WWW at http://bodymap.ims.u-tokyo.ac.jp

Animals↗
PubMed2000

A single institutional outcome analysis of Gamma Knife radiosurgery for single or multiple brain metastases.

Although Gamma Knife stereotactic radiosurgery (SRS) is widely used for metastatic brain tumors, optimal patient selection and treatment strategy continue to be investigated. The aim of this study was to provide treatment results with Gamma Knife SRS and to establish prognostic factors. Of the 54 patients treated from 1990 to 1997, 51 patients were evaluable. There were 28 males and 23 females, with a median age of 60 years. Median Karnofsky Index was 80. There were 19 non-small cell lung cancers, eight colon cancers, six renal cell cancers, five ovarian cancers, four gastric cancers, three breast cancers, and six others. Primary tumors were controlled in 33 patients, and extracranial tumors were absent in 25 patients. Sixty-eight metastatic brain tumors in 37 patients underwent SRS as an initial treatment for the brain metastasis. Brain metastasis was solitary in 32 patients. Conventional radiation was combined with SRS in 29 patients, 24 of whom received whole brain radiotherapy. Eight patients had some form of surgical resection. Median survival time was 7.4 months. Five-year actuarial survival and local control rates were 16 and 52%, respectively. Median duration time of keeping pretreatment quality of life was 6.9 months. On a multivariate analysis, uncontrolled primary tumor, combined conventional radiotherapy, and performance status were statistically significant prognostic factors. Four patients who underwent whole brain radiation developed low grade dementia.

Adult↗
PubMed2000

Nontraumatic osteonecrosis: MR perfusion imaging evaluation in an experimental model.

RATIONALE AND OBJECTIVES: Because the nature and time course of changes in early, nontraumatic osteonecrosis at perfusion and magnetic resonance (MR) imaging are unknown, the authors evaluated this technique in the assessment of early osteonecrosis with a nontraumatic model. MATERIALS AND METHODS: Five rabbits underwent intravenous injection of lipopolysaccharide endotoxin followed by intramuscular injection of methylprednisolone. MR imaging of the femora was performed before and at weekly intervals after endotoxin injection. Histologic findings from the areas of osteonecrosis were correlated with the findings of MR imaging and MR perfusion studies. RESULTS: Histologic evaluation showed osteonecrosis in six femora of four animals 2-4 weeks after endotoxin injection. Findings on T1-weighted images of the femur were normal in all animals; T2-weighted images of one femur showed equivocal changes. On MR perfusion images, the baseline mean peak percentage of enhancement was 52.7% +/- 12.6. In the six areas without osteonecrosis, the mean percentage of enhancement was similar to the baseline percentage of enhancement at 1 week (62.2% +/- 31.2). In the four areas with diffuse osteonecrosis, there was essentially no contrast enhancement 1-4 weeks after endotoxin injection. CONCLUSION: T1- and T2-weighted MR imaging is insensitive to the presence of early nontraumatic osteonecrosis. MR perfusion imaging might be useful to detect early nontraumatic osteonecrosis.

Animals↗
PubMed2000

Purification and characterization of sea squirt alpha-N-acetylgalactosaminidase.

Sea squirt alpha-N-acetylgalactosaminidase was purified to homogeneity. Its molecular weight was estimated to be approximately 160,000 by gel filtration and 40,000 by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing condition. The chromatographic and electrophoretic behaviors indicated that the enzyme was composed of four subunits. The optimum pH of the enzyme reaction was about 4.0 at 37 degrees C, while the enzyme was stable in the range of pH 5.0 to 6.0 during 4 h preincubation at 37 degrees C. Although the enzyme (0.1 unit) was stable at 0 degrees C for 30 min in the presence of 7.5 mM metal ions (Al3+, Ba2+, Ca2+, K+, Mn2+, Pb2+, Sr2+, and Zn2+), almost 40% of the enzyme activity was lost in the presence of Cu2+, Hg2+, monoiodoacetic acid, and EDTA. The enzyme hydrolyzed aryl N-acetyl-alpha-D-galactosaminide as well as GalNAcalpha1(-->4GalNAcalpha1-->)n 4GalNAc-p-aminobenzoic acid ethyl ester (ABEE) (n = 1-4), but GalNAcalpha1-->4GalNAc-ABEE only scarcely. Furthermore, an allergenic pentasaccharitol ABEE derivative, GalNAcalpha1-->2Fucalpha1-->3(GalNAcbeta1-->4) GlcNAcbeta1-->2(3-acetoamido-3-deoxy)L-threose-ABEE, the minimum structural unit for the sea squirt allergenicity was hydrolyzed to 95 mol% for 72 h incubation with the enzyme. The enzyme could be utilized as a powerful tool for the structural analyses of the carbohydrate epitopes of the sea squirt allergen molecules.

Journal Article↗
PubMed2000

Acute abdomen without cutaneous signs of varicella zoster virus infection as a late complication of allogeneic bone marrow transplantation: importance of empiric therapy with acyclovir.

Two patients complained of severe abdominal pain as the first sign of varicella zoster virus infection about 1 year after allogeneic BMT. In case 1, eruptions, found on the face and chest on admission, became vesicular and dispersed on the third hospital day. Though acyclovir (ACV) was immediately started, he died on the fourth day. In case 2, skin rash was never observed during the clinical course. Laparotomy on the third hospital day revealed many hemorrhagic spots on the liver surface and mucous membrane of the upper GI tract, indicating disseminated visceral disease. Empiric therapy with ACV was successful.

Abdominal Pain↗
PubMed2000

Late onset cyclosporine-induced cerebral blindness with abnormal SPECT imagings in a patient undergoing unrelated bone marrow transplantation.

A 23-year-old woman underwent HLA-matched unrelated BMT for CML. She developed cerebral blindness on day 81. Brain magnetic resonance imaging revealed hyperintensity on a T2-weighted image in the white and gray matter of the right frontal and both occipital lobes. Single-photon emission computed tomography (SPECT) was consistent with a decrease in radionuclide uptake in these areas, suggesting a vasoconstrictive mechanism. A diagnosis of CsA-induced encephalopathy was made and CsA was discontinued. Her vision recovered completely after 24 h and abnormal imaging resolved within 2 weeks. This case demonstrates late onset CsA-induced cerebral blindness with the previously unreported abnormalities on SPECT.

Aged↗
PubMed2000

Possible role of L-selectin in T lymphocyte alveolitis in patients with active pulmonary sarcoidosis.

A number of adhesion molecules participate in the recruitment of inflammatory cells to the site of inflammation, and selectins together with their ligands are important in the early transient adhesion phase. In this study, we evaluated the role of L-selectin in T lymphocyte alveolitis in patients with active pulmonary sarcoidosis. We measured serum and bronchoalveolar lavage fluid (BALF) concentrations of soluble (s)L-selectin using an ELISA. Serum and BALF concentrations of sL-selectin were significantly elevated in patients with sarcoidosis compared with control healthy subjects and idiopathic pulmonary fibrosis (IPF) patients (P < 0.05 and P < 0. 01, respectively). The lymphocyte surface marker was also examined in peripheral blood and BALF by flow cytometric analysis. The percentage of CD3+CD62L+ cells (L-selectin-bearing T lymphocytes) was significantly lower in peripheral blood of sarcoidosis than in that of healthy subjects (P < 0.01). In contrast, the percentage of CD3+CD62L- cells (L-selectin-negative T lymphocytes) in BALF of patients with sarcoidosis was significantly higher than in healthy subjects (P < 0.05) and IPF patients (P < 0.01). Furthermore, there was a significant correlation between serum concentrations of sL-selectin and the number of L-selectin-negative T lymphocytes in BALF (r = 0.535, P < 0.01). Our results suggest that L-selectin may be involved in T lymphocyte alveolitis in patients with active pulmonary sarcoidosis.

Adult↗
PubMed2000

The effect of oestrogen deficiency on the alveolar bone resorption caused by traumatic occlusion.

This study, using 132 female rats, was designed to investigate whether oestrogen loss facilitates alveolar bone alterations induced by traumatic occlusion. Rats were ovariectomized (OVX) or underwent sham-operation (Sham). Seven days after surgery, half of the rats in each group were subjected to experimental traumatic occlusion (trauma), and the other half were left untreated. Thus, there were four groups: OVX+trauma, Sham+trauma, OVX, and Sham. Rats in each group were killed 1, 3, 5, 7, or 10 days after the introduction of occlusal trauma. The resected mandibles were processed without decalcification, and histomorphometric measurements were performed in the alveolar bone adjacent to the periodontal ligament of the first molar. The statistical assessment of the time- and group-specific differences by analysis of variance revealed significant differences between the OVX+trauma and Sham+trauma groups in the resorption parameters, but not in the formation parameters. The results show that the alveolar bone dynamics induced by traumatic occlusion are enhanced by oestrogen deficiency.

Alveolar Bone Loss↗
PubMed2000

Gene expression profiles of the collecting duct in the mouse renal inner medulla.

UNLABELLED: Gene expression profiles of the collecting duct in the mouse renal inner medulla. BACKGROUND: Gene expression profiles, constructed from 1000 to 2000 cloned cDNA sequences, depict their relative abundance of expression in a tissue. Establishing such a profile for mouse inner renal medullary collecting ducts (IMCDs), we compared expression patterns with those in other tissues including proximal tubule. METHODS: A nonbiased 3'-end cDNA library was prepared from microdissected mouse IMCDs. Single-pass sequencing of 2000 randomly selected cDNA clones collected short sequences (approximate length, 250 bp) following poly (A), called gene signatures (GS). Identical sequences were considered a single GS. GS occurrence was quantitated to yield a list of expressed genes indicating their abundance. RESULTS: Among 2000 clones, 1613 types of transcripts were found in IMCDs; 155 were identical or homologous to reported genes. The gene most expressed in IMCDs was alphaB-crystallin, a small stress (heat-shock) protein that is also a major structural protein in the ocular lens. According to Northern analysis, renal expression of this mRNA was induced by dehydration, presumably via tissue hypertonicity. However, expression did not change with acute NaCl loading. Also, a new member of the glutathione-S-transferase family was identified by comparing the IMCD expression profile with those of other tissues. CONCLUSION: With our database of genes expressed in mouse IMCDs, we are devising an IMCD-specific microarray to study gene-expression responses to various physiologic alterations.

Amino Acid Sequence↗
PubMed2000

Serum levels of soluble IL-2 receptor, IL-12, IL-18, and IFN-gamma in patients with acute graft-versus-host disease after allogeneic bone marrow transplantation.

BACKGROUND: Acute graft-versus-host disease still represents the major factor that limits successful allogeneic bone marrow transplantation. Cytokines released by type 1 T-helper cells are thought to play a pivotal role in acute graft-versus-host disease. OBJECTIVE: This study was performed to investigate whether the serum levels of soluble IL-2 receptor, IL-12, IL-18, and IFN-gamma were associated with the manifestation of acute graft-versus-host disease. METHODS: Serum cytokine levels were measured by sandwich ELISA in 18 patients who underwent allogeneic bone marrow transplantation. RESULTS: Serum levels of soluble IL-2 receptor, IL-12, IL-18, and IFN-gamma were increased in patients in whom acute graft-versus-host disease developed. However, only serum soluble IL-2 receptor levels were significantly related to disease severity. Serum levels of IL-12 and IL-18, both of which are mainly produced by activated macrophages, were increased in different phases of acute graft-versus-host disease, especially grade I. Serum levels of soluble IL-2 receptor and IFN-gamma were significantly elevated in patients with fever. CONCLUSION: Serum levels of soluble IL-2 receptor were more closely related to the severity of acute graft-versus-host disease than those of IL-12, IL-18, and IFN-gamma.

Acute Disease↗
PubMed2000

Isolation and characterization of a Ca(2+)-activated chloride channel from human corneal epithelium.

PURPOSE: Transparency of the cornea is maintained through the activity of secretory mechanisms in the epithelium and endothelium, which offset the tendency of the stroma to imbibe fluid and swell. These secretory mechanisms establish osmotic gradients thereby providing the osmotic driving forces for coupled fluid transport from the stroma into both the tears and the anterior chamber. To further characterize the mechanism of epithelial Cl secretion, we cloned a cDNA encoding a Ca(2+)-dependent chloride channel, an abundant mRNA in human corneal epithelium. We investigated the abundance of all known human chloride channels in corneal epithelium to identify those responsible for regulating chloride conductance in this tissue. METHODS: For the isolation of a full-length cDNA clone, a probe was selected from a set of expressed sequenced tag (EST) clones classified as unique to corneal epithelium (http://bodymap. ims.u-tokyo.ac.jp). The expression patterns of the corresponding gene encoding novel chloride channel gene in human cornea and other tissues were examined by reverse transcription-polymerase chain reaction (RT-PCR). Quantitative PCR was performed to clarify the expression level of the novel chloride channel gene in cornea relative to that in other human tissues. RESULTS: We cloned a new Ca(2+)-activated chloride channel, CLCA2, from corneal epithelium. The full length cDNA clone encoded 943 amino acids with 62% identity to bovine Ca(2+)-activated chloride channel. The CLCA2 gene mapped to human chromosome 1p32. Quantitative expression analysis by RT-PCR showed that it is the most abundant chloride channel in corneal epithelium. CONCLUSION: High and tissue specific expression of the CLCA2 gene in human corneal epithelium implies an important role in corneal transparency maintenance.

Amino Acid Sequence↗