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Biomedical subjects

N Komatsu

Publications and source records attributed to N Komatsu.

At least 19 recordsLinked to original sources
PubMed2006

A case of a Japanese neonate with congenital ichthyosiform erythroderma diagnosed as Netherton syndrome.

We report a 6-day-old Japanese girl showing generalized erythroderma accompanied by yellowish, exfoliative scaling that was accentuated on the face and scalp. Histological analysis showed psoriasiform dermatitis with acanthotic epidermis and premature shedding of the stratum corneum. Measurement of trypsin-like hydrolytic activity in SC showed six-fold greater activity compared with age-matched controls. DNA analysis revealed two mutations, 375delAT and 966insC, in exons 5 and 11, respectively, of the SPINK5 gene. Although at 4 weeks the child was still too young to display characteristic hair abnormalities or atopic diathesis, we diagnosed Netherton syndrome based on enzyme assay and DNA analysis.

Carrier Proteins↗
PubMed2005

Multiple tissue kallikrein mRNA and protein expression in normal skin and skin diseases.

BACKGROUND: Human tissue kallikreins are a gene family (KLK1-KLK15) encoding for 15 secretory serine proteases (hK1-hK15). Two tissue kallikrein proteins, hK5 and hK7, were previously found in the stratum corneum (SC), stratum granulosum (SG) and appendages. hK8 was also shown to be secreted via lamellar granules and numerous KLK mRNAs were previously identified. KLKs are believed to be responsible for desquamation of corneocytes and sebum, sweat and hair maturation. OBJECTIVES: To demonstrate immunohistochemically the expression of hK6, hK8 and hK13 in normal skin tissue and to show an increased cell number expressing kallikrein mRNAs and proteins in psoriasis vulgaris (PV) and atopic dermatitis (AD). METHODS: Samples of normal, PV and AD skin were obtained. hK6-, hK8- and hK13-specific antibodies were produced and used for immunohistochemical analysis. Multiple KLK mRNAs were synthesized and used for in situ hybridization study. RESULTS: Three other hKs, namely hK6, hK8 and hK13, were immunohistochemically identified as new skin serine proteases in the whole SC, SG, sebaceous glands, eccrine sweat glands, hair follicles and nerves. We also demonstrated an increased number of cells expressing KLK mRNAs and hKs in PV and AD. In PV, KLK mRNAs/hKs were predominantly expressed in the upper epidermis. In AD, hK distribution was rather diffuse and expanded into the lower epidermis. CONCLUSIONS: The colocalization of various hKs seems to be essential for the regulation of serine protease activity in skin and for steady desquamation and skin barrier function. Moreover, the increased number of cells expressing multiple KLK mRNA and hK in PV and AD could be a clue to elucidate their pathogenesis.

Adult↗
PubMed2004

New multiplexed flow cytometric assay to measure anti-peptide antibody: a novel tool for monitoring immune responses to peptides used for immunization.

Peptide-based vaccination has a great potential for the prevention and treatment of various diseases. There is, however, no appropriate monitoring system to measure immune responses to vaccinated peptides, which hampers the development of therapeutically effective vaccine regimens to various diseases. In this study a new multiplexed flow cytometric assay using the Luminex system to monitor humoral immune responses to vaccinated peptides is described. Although the sensitivity is mostly equal to that of the traditional enzyme-linked immunosorbent assay (ELISA), the new assay has several advantages over ELISA in that it minimizes the amount of sera needed, running costs and working periods, and thus will be a novel tool for monitoring immune responses to vaccinated peptides.

Antibodies↗
PubMed2004

Assessment of synthetic peptides of severe acute respiratory syndrome coronavirus recognized by long-lasting immunity.

In order to determine highly immunogenic severe acute respiratory syndrome coronavirus (SARS-CoV) epitope peptides capable of inducing long-lasting immunity, we first screened immunoglobulin-G (IgG) antibodies reactive to 197 different overlapping 15-mers from the SARS-CoV proteins in the sera of three infected patients. Forty-two peptides among them were reactive to the sera from all three patients. Consequently, we tested for the reactivity of these 42 peptides to patients' sera (n = 45) at 6-month post-infection. The significantly higher levels of IgG antibodies specific to three (S791, M207 and N161) of 42 peptides were detectable in the post-infection sera from 23 (51%), 27 (60%) and 19 (42%) of 45 patients, respectively. These three peptides, recognized by their long-lasting immunity, may provide a better understanding of the immunogenicity of SARS-CoV.

Enzyme-Linked Immunosorbent Assay↗
PubMed2004

Analysis of cellular localization of SART3 tumor antigen by a newly established monoclonal antibody: heterotopic expression of SART3 on the surface of B-lineage leukemic cells.

SART3 has been identified as a tumor antigen recognized by cytotoxic T-lymphocytes. Subcellular localization of SART3 is still controversial, although it has been studied extensively. In this study, we established an anti-SART3 monoclonal antibody (mAb) to analyze the subcellular localization of SART3 in tumor specimens. Immunohistochemical analysis demonstrated that SART3 was preferentially expressed in the nucleus of cancer cells. Flow cytometric analysis indicated that SART3 was not expressed on the cell surface of tumor cells, except for B-lineage cells. SART3 was detected on the cell surface of several B-lineage leukemic cells with different maturation stages, but not on normal peripheral blood B cells. These results suggest that heterotopically expressed SART3 is a tumor-associated antigen rather than a differentiation antigen on B-lineage cells.

Animals↗
PubMed2003

Heat shock cognate protein 70 encodes antigenic epitopes recognised by HLA-B4601-restricted cytotoxic T lymphocytes from cancer patients.

Heat shock cognate protein 70 (HSC70), a highly conserved protein and a member of the family of molecular chaperones, has the ability to induce cytotoxic T lymphocyte (CTL) responses through binding and carrying antigenic peptides. We demonstrated in this study that the HSC70 gene encodes two antigenic peptides recognised by HLA-B46-restricted and tumour-reactive CTLs established from tumour-infiltrating lymphocytes of a colon cancer. These HSC70-derived peptides, at amino-acid positions 106-114 and 233-241, had the ability to induce HLA-B46-restricted and peptide-specific CTLs, which are reactive to tumour cells, from peripheral blood mononuclear cells of the majority of epithelial cancer patients tested. These results, along with those from the previous studies, indicate the two ways of HSC70 involvement in the immune responses to tumours: chaperones and antigens, and thus may provide a new insight for the development of HSC70-directed cancer-specific immunotherapy.

Animals↗
PubMed2001

Characterization of stage progression in chronic myeloid leukemia by DNA microarray with purified hematopoietic stem cells.

Chronic myeloid leukemia (CML) is characterized by the clonal expansion of hematopoietic stem cells (HSCs). Without effective treatment, individuals in the indolent, chronic phase (CP) of CML undergo blast crisis (BC), the prognosis for which is poor. It is therefore important to clarify the mechanism underlying stage progression in CML. DNA microarray is a versatile tool for such a purpose. However, simple comparison of bone marrow mononuclear cells from individuals at different disease stages is likely to result in the identification of pseudo-positive genes whose change in expression only reflects the different proportions of leukemic blasts in bone marrow. We have therefore compared with DNA microarray the expression profiles of 3456 genes in the purified HSC-like fractions that had been isolated from 13 CML patients and healthy volunteers. Interestingly, expression of the gene for PIASy, a potential inhibitor of STAT (signal transducer and activator of transcription) proteins, was down-regulated in association with stage progression in CML. Furthermore, forced expression of PIASy has induced apoptosis in a CML cell line. These data suggest that microarray analysis with background-matched samples is an efficient approach to identify molecular events underlying the stage progression in CML.

AC133 Antigen↗
PubMed2001

Forkhead family transcription factor FKHRL1 is expressed in human megakaryocytes. Regulation of cell cycling as a downstream molecule of thrombopoietin signaling.

FKHRL1, a member of the Forkhead transcription factor family, is one of the downstream molecules of phosphatidylinositol 3-kinase-Akt. This molecule is a mammalian homolog of DAF-16, which plays an important role in the longevity of Caenorhabditis elegans. In this study we found that Akt and FKHRL1 proteins were detectable in highly purified normal human megakaryocytes and that these molecules were actually phosphorylated by thrombopoietin (TPO). To clarify the functional role of FKHRL1 in TPO signaling, we established a tetracycline-inducible system in the human TPO-dependent leukemia cell line UT-7/TPO. Induced expression of active FKHRL1 led to cell cycle arrest at G0/G1 phase in this cell line. These results suggest that FKHRL1 plays an important role in the cell cycle of megakaryocytic cells as one of the downstream target molecules of phosphatidylinositol 3-kinase-Akt, presumably mediated through the activation or inactivation of cell cycle-associated gene(s).

Cell Cycle↗
PubMed2001

A functional role of mitogen-activated protein kinases, erk1 and erk2, in the differentiation of a human leukemia cell line, UT-7/GM: a possible key factor for cell fate determination toward erythroid and megakaryocytic lineages.

The mitogen-activated protein (MAP) kinase cascade is a key regulator of mammalian cell proliferation and differentiation. In this study, we examined the roles of 2 members of the MAP kinase family, extracellular signal-regulated kinase 1 (Erk1) and Erk2, in erythropoietin (EPO)-induced erythroid differentiation and thrombopoietin (TPO)-induced megakaryocytic differentiation. UT-7/GM was used as a model system because this cell line is an erythroid/megakaryocytic bipotent cell line that can be induced to differentiate into the erythroid and megakaryocytic lineages by EPO and TPO, respectively. The kinetics of activation of Erk1 and Erk2 were examined during erythroid and megakaryocytic differentiation of UT-7/GM cells. EPO induced a transient activation of these kinases, peaking after 1 minute of stimulation and then declining quickly almost to the basal level. In contrast, TPO-induced activation of the kinases peaked at 10 minutes and persisted for up to 60 minutes, similar to the activation by granulocyte-macrophage colony-stimulating factor. The percentage of EPO-induced hemoglobin-positive cells was elevated by the addition of PD98059, a specific inhibitor of MEK1 (MAP kinase/ERK kinase 1). In contrast, PD98059 clearly reduced the amount of glycoprotein IIb/IIIa antigens induced by TPO on UT-7/GM cells. Thus, inactivation of Erk1 and Erk2 kinases promoted EPO-induced erythroid differentiation and suppressed TPO-induced megakaryocytic differentiation of UT-7/GM cells. In conclusion, the activation of Erk1 and Erk2 kinases may be a critical event in the determination of cell fate and the differentiation processes of the erythroid and megakaryocytic lineages.

Cell Differentiation↗
PubMed2001

Adult-onset herpes simplex virus hepatitis with diffuse myofibroblastic transformation of hepatic stellate cells (Ito cells) in non-necrotic areas.

The myofibroblastic transformation of hepatic stellate cells (HSC; also known as Ito cells) usually occurs following necrosis of adjacent liver cells. No report has previously found that such a transformation occurs in herpes simplex virus (HSV) hepatitis. We present an autopsy case of HSV hepatitis with myofibroblastic transformation of HSC that is different from the usual transformation of HSC. The patient was a 66-year-old woman who had received various therapies for cutaneous T-cell lymphoma. An autopsy revealed submassive hepatic necrosis with hemorrhage due to HSV hepatitis. HSV infection was confirmed by DNA in situ hybridization in liver tissue. Immunohistochemical staining for alpha-smooth muscle actin (ASMA) showed a strong positive reaction in almost all of the HSC in non-necrotic areas. However, in necrotic areas, the HSC were completely negative for ASMA. These findings indicate that not only liver cells but also HSC can become necrotic in HSV hepatitis. In contrast, in non-necrotic areas, almost all of the HSC showed active transformation to myofibroblasts.

Actins↗
PubMed2001

Enzyme-cytochemically detectable glucose-6-phosphate dehydrogenase in human villous macrophages (Hofbauer cells).

Though various tissue macrophages possess high glucose-6-phosphate dehydrogenase (G6PD) activity, which plays an important role in their phagocytosis/bactericidal function, the presence of this enzyme in human placental villous macrophages (Hofbauer cells) has not been determined. We examined the ultrastructural localization of glucose-6-phosphate dehydrogenase (G6PD) in Hofbauer cells in first and second trimester placental villi, using a newly developed enzyme-cytochemistry (copper-ferrocyanide) method. Electron-dense deposits indicative of G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of Hofbauer cells. Positive and negative cytochemical controls ensured specific detection of enzyme activity. These observations indicated that Hofbauer cells abundantly possessed enzyme-cytochemically detectable G6PD activity. Hofbauer cell G6PD may play a role in placental defense, by supplying NADPH-dependent enzymes (i.e. nitric oxide synthase or NADPH oxidase) with NADPH. This enzyme may also fuel Hofbauer cells with ribose 5-phosphate during their cell proliferation and cell division.

Cytoplasm↗
PubMed2001

Pemphigus foliaceus developing after metastasis of cutaneous squamous cell carcinoma to regional lymph nodes.

We describe a patient in whom pemphigus foliaceus developed after cutaneous squamous cell carcinoma (SCC) metastasized to regional lymph nodes. Immunologic analysis revealed that production of anti-desmoglein 1 autoantibodies started when SCC metastasized, and the SCC expressed desmoglein 1, suggesting a pathogenic role of metastasized SCC in developing pemphigus foliaceus.

Aged↗
PubMed2001

Colon cancer with meningeal carcinomatosis and myelodysplastic syndrome in a patient who underwent intensive chemotherapy for acute myelogenous leukemia: a case report.

A 59-year-old man was admitted to our hospital because of disturbance of consciousness and hyponatremia. The patient had suffered from acute myelogenous leukemia (AML) with 46,XY and received chemotherapy for 5 years. Meningeal carcinomatosis was diagnosed due to the detection of carcinoma cells in the cerebrospinal fluid (CSF). Hyponatremia was caused by syndrome of inappropriate secretion of anti-diuretic hormone (SIADH). Bone marrow examination revealed myelodysplastic syndrome (MDS) with deletion of the long arm of chromosome 7. Emergence of a new abnormal clone was suggested. The patient died from brain herniation. Post mortem examination showed adenocarcinoma in the colon. An association between chemotherapy and both colon cancer and MDS was suggested.

Adenocarcinoma↗
PubMed2001

[Outcome of acute myelogenous leukemia in 41 patients treated with idarubicin: the prognosis of t(8;21) cases].

Idarubicin (IDR) has been used as the main drug in induction chemotherapy for acute myelogenous leukemia (AML) in the USA and Europe. Between May 1995 and October 1998, we treated 41 cases of fresh AML using IDR induction chemotherapy and analyzed the clinical course, remission rate, relapse rate and prognosis. The results obtained in these cases were similar to those in 26 cases treated with daunorubicin (DNR) in our hospital according to JALSG-AML92. The outcome in cases with abnormal chromosomes and cases showing relapse was very poor. In particular, all 5 t(8;21) cases in our series relapsed, suggesting that t(8;21) cannot be considered a favorable prognostic factor in cases treated with IDR-containing regimens. However, 3 of the 5 t(8;21) cases were positive for CD56, which itself is an unfavorable prognostic factor. Thus it is possible that CD56 was related to the poor outcome. Intensive post-remission induction chemotherapies will be required in order to obtain prolonged disease-free survival.

Adult↗
PubMed2000

Mechanism of superoxide anion generation in the toxic red tide phytoplankton Chattonella marina: possible involvement of NAD(P)H oxidase.

Red tide phytoplankton Chattonella marina is known to produce reactive oxygen species (ROS), such as superoxide anion (O(2)(-)), hydrogen peroxide (H(2)O(2)) and hydroxyl radical (&z.rad;OH), under normal physiological conditions. Although several lines of evidence suggest that ROS are involved in the mortality of fish exposed to C. marina, the mechanism of ROS generation in C. marina remains to be clarified. In this study, we found that the cell-free supernatant prepared from C. marina cells showed NAD(P)H-dependent O(2)(-) generation, and this response was inhibited by diphenyleneiodonium, an inhibitor of mammalian NADPH oxidase. When the cell-free supernatant of C. marina was analyzed by immunoblotting using antibody raised against the human neutrophil cytochrome b558 large subunit (gp91phox), a main band of approximately 110 kDa was detected. The cell surface localization of the epitope recognized with this antibody was also demonstrated in C. marina by indirect immunofluorescence. Furthermore, Southern blot analysis performed on genomic DNA of C. marina with a probe covering the C-terminal region of gp91phox suggested the presence of a single-copy gene coding for gp91phox homologous protein in C. marina. These results provide evidence for the involvement of an enzymatic system analogous to the neutrophil NADPH oxidase as a source of O(2)(-) production in C. marina.

Amino Acid Sequence↗
PubMed2000

Thrombopoietin and interleukin-2 induce association of CRK with STAT5.

Crk (Crk I and II) proteins and closely related CrkL are adapters which are commonly involved in various signaling processes in various cells, and these proteins share many ligands. Whether they have redundant or distinct physiologic roles is unclear. By coprecipitation and far Western blotting analysis, we demonstrate that Crk (I/II) binds to tyrosine phosphorylated STAT5 in cells stimulated by cytokines such as thrombopoietin (TPO) and interleukin-2 (IL-2). The association did not require nuclear elements and can be observed in primary cells as this was also demonstrated in TPO-stimulated platelets. Using a beta-casein promoter STAT5 binding site as a probe, we have also demonstrated that CrkL (a close relative of Crk) antiserum, but not Crk antiserum, supershifted the STAT5-DNA complex by an electrophoretic mobility shift assay, suggesting that CrkL, but not Crk, is the major component of the complex. Thus, Crk and CrkL may have distinct roles in the regulation of STAT5.

Base Sequence↗
PubMed2000

A member of Forkhead family transcription factor, FKHRL1, is one of the downstream molecules of phosphatidylinositol 3-kinase-Akt activation pathway in erythropoietin signal transduction.

The phosphatidylinositol 3-kinase (PI3K) signaling pathway is important for the regulation of a number of cellular responses. Serine/threonine kinase Akt (protein kinase B; PKB) is downstream of PI3K and activated by growth factors. This study found that erythropoietin (EPO) induced tyrosine phosphorylation of Akt in a time- and dose-dependent manner in EPO-dependent human leukemia cell line UT-7/EPO. In vitro kinase assay using histone H2B and glucose synthase kinase as substrates demonstrated that Akt was actually activated by EPO. EPO-induced phosphorylation of Akt was completely blocked by a PI3K-specific inhibitor, LY294002, at 10 micromol/L, indicating that activation of Akt by EPO is dependent on PI3K activity. In addition, overexpression of the constitutively active form of Akt on UT-7/EPO cells partially blocked apoptosis induced by withdrawal of EPO from the culture medium. This finding suggested that the PI3K-Akt activation pathway plays some role in the antiapoptotic effect of EPO. EPO induced phosphorylation of a member of the trancription factor Forkhead family, FKHRL1, at threonine 32 and serine 253 in a dose- and time-dependent manner in UT-7/EPO cells. Moreover, results showed that Akt kinase activated by EPO directly phosphorylated FKHRL1 protein and that FKHRL1 phosphorylation was completely dependent on PI3K activity as is the case for Akt. In conjunction with the evidence that FKHRL1 is expressed in normal human erythroid progenitor cells and erythroblasts, the results suggest that FKHRL1 plays an important role in erythropoiesis as one of the downstream target molecules of PI3K-Akt.

DNA-Binding Proteins↗