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Biomedical subjects

Yuko Sato

Publications and source records attributed to Yuko Sato.

At least 19 recordsLinked to original sources
PubMed2003

Suppression of ARG kinase activity by STI571 induces cell cycle arrest through up-regulation of CDK inhibitor p18/INK4c.

ARG is a tyrosine kinase closely related to ABL, which is oncogenic when fused to the transcriptional repressor ETV6 (ETS translocation variant 6). In this study, we investigated the growth-inhibitory effect of STI571 (signal transduction inhibitor number 571) on ETV6/ARG-expressing cells and its molecular mechanisms using HT93A, a cell line derived from a patient with AML-M3 carrying t(1;12). STI571 effectively suppressed overall tyrosyl phosphorylation of intracellular proteins including ETV6/ARG fusion protein, as well as the growth of HT93A cells with an IC(50) of 200 nM. The growth inhibition was primarily because of cell cycle arrest at G1 phase when cells were treated with 100 nM STI571 for 48 h, and apoptosis was induced after longer exposure (72 h) or by a higher dose (1000 nM). STI571 increased the amount of p18/INK4c after 2 h of culture, when the cell cycle pattern was not yet affected, but not that of other CDK inhibitors (CKI). p18/INK4c was more abundant in G1-enriched fractions than in S- and G2/M-enriched fractions of STI571-treated HT93A cells, suggesting that the upregulation of p18/INK4c expression correlates with the cell cycle arrest. Treatment of HT93A cells with antisense oligonucleotides against the Ink4c gene abrogated the growth inhibition by STI571. These results suggest that leukemogenesis by an aberrant ARG kinase involves the suppression of p18/INK4c, which is ubiquitously expressed and considered the major CKI in hematopoietic stem cells. STI571 can be an effective drug for the treatment of leukemias with deregulated ARG kinase activity.

Antineoplastic Agents↗
PubMed2003

Roles of anti-hemagglutinin IgA and IgG antibodies in different sites of the respiratory tract of vaccinated mice in preventing lethal influenza pneumonia.

The roles of IgA and IgG antibodies (Abs) against hemagglutinin (HA) in the prevention of lethal influenza pneumonia in vaccinated mice were examined in terms of distribution and concentration of the Abs in the mucus or the serous fluid in different sites of the respiratory tract (RT), mucosa of the nose, trachea, bronchi and bronchioli and the alveolar epithelia of pulmonary acinus. First, the surface areas of the tracheal, bronchial and bronchiolar mucosa and alveolar epithelia were measured to be 20, 260 and 217, 433 mm(2), respectively, using serial tissue sections of the trachea and lungs. Then, the volumes of the tracheal mucus, the bronchial and bronchiolar mucus and the serous fluid of alveolar epithelia were estimated to be 0.2, 2.6 and 21.7 mm(3), respectively, by calculating each from the surface area and an assumed thickness of the mucus layer (0.01 mm) or that of the serous fluid (0.0001 mm). Next, anti-HA IgA and IgG Ab responses in the nasal wash, the trachea-lung wash and the trachea wash were measured in BALB/c mice immunized intranasally with an adjuvant-combined A/PR/8/34 (H1N1) virus vaccine and challenged with a lethal dose of the virus. Then the values of Ab responses were converted to the mucus and serous fluid Ab concentration based on two premises that the serum Abs diffuse at a constant rate to the surface of the tracheal, bronchial and bronchiolar mucosa, and that the active transepithelial transport of IgA Abs does not work in the alveolar epithelia. Results showed that 21.4 microg/ml IgA Abs and 3.6 microg/ml IgG Abs in the tracheal mucus (19.1 and 0.3% of the trachea-lung wash IgA and IgG Ab amounts, respectively), 5.9 microg/ml IgA Abs and 3.6 microg/ml IgG Abs in the bronchial and bronchiolar mucus (66.0 and 3.4% of the trachea-lung wash IgA and IgG Ab amounts, respectively) and about 0.1 microg/ml IgA Abs and 12.3 microg/ml IgG Abs in the serous fluid of alveolar epithelia (14.9 and 96.3% of the trachea-lung wash IgA and IgG Ab amounts, respectively) were present in the vaccinated mice, at which concentrations influenza pneumonia was prevented. Thus, 96.3% of anti-HA IgG Abs in the trachea-lung wash work on the alveolar epithelia, whose surface area is about 800 times larger than that of tracheal, bronchial and bronchiolar mucosa and seem to play a more important role than the mucosal IgA Abs in the prevention of lethal influenza pneumonia.

Animals↗
PubMed2003

Breakpoints at 1p36.3 in three MDS/AML(M4) patients with t(1;3)(p36;q21) occur in the first intron and in the 5' region of MEL1.

The recurrent translocation t(1;3)(p36;q21) is associated with myelodysplastic syndrome (MDS)/acute myelogenous leukemia (AML) characterized by trilineage dysplasia, especially dysmegakaryopoiesis and a poor prognosis. Recently, the two genes involved in this translocation have been identified: the MEL1 gene at 1p36.3, and the RPN1 gene at 3q21. The breakpoint in RPN1 is centromeric to the breakpoint cluster region of the inv(3) abnormality. Because the MEL1 transcript is detected only in leukemic cells with t(1;3)(p36;q21), ectopic expression of MEL1 driven by RPN1 at 3q21 is thought to contribute to the pathogenesis of t(1;3)(p36;q21) leukemia. However, the precise breakpoint in the patients has not yet been identified. With fluorescence in situ hybridization analysis by use of BAC/PAC probes, we identified the breakpoint at 1p36.3 in three MDS/AML patients with t(1;3)(p36;q21): within the first intron of the MEL1 gene (one patient) or within a 29-kb region located in the 5' region of MEL1 (two other patients). We detected several sizes of MEL1 transcript in two patients including the first patient, although we have not yet clarified whether MEL1 transcripts were different among the patients and whether a truncated MEL1 transcript was expressed in the first patient. This patient showed an unusual clinical profile, repeating progression to overt leukemia and conversion to MDS three times during the 29-month survival period, which might be related to a different molecular mechanism in this patient.

5' Flanking Region↗
PubMed2003

In situ hybridization AT-tailing with catalyzed signal amplification for sensitive and specific in situ detection of human immunodeficiency virus-1 mRNA in formalin-fixed and paraffin-embedded tissues.

In situ hybridization is one of the most important techniques to visualize gene expression at the cellular level in various tissues. The in situ hybridization-AT tailing (ISH-AT) method uses a specially designed and synthesized oligonucleotide probe that has (AT)10 on the 3' side. This (AT)10 of the probe is elongated by DeltaTth DNA polymerase in the presence of dATP, dTTP, and labeled dUTP in the tissue after hybridization. Through this process the target is labeled with many hapten molecules. In this study, we detected human immunodeficiency virus type 1 RNA in formalin-fixed and paraffin-embedded tissues obtained from autopsied patients with acquired immunodeficiency syndrome by combining ISH-AT with the catalyzed signal amplification (CSA) system (ISH-AT-CSA), although we failed to detect signals from the same samples by conventional in situ hybridization using RNA probes (RISH) with CSA (RISH-CSA). We demonstrated that the ISH-AT-CSA method was superior to RISH-CSA in terms of both sensitivity and specificity, and that it was applicable to fluorescence in situ hybridization and double staining with immunohistochemistry for the characterization of cell phenotypes.

Adenine↗
PubMed2003

Cross-reactive antigenicity of nucleoproteins of lyssaviruses recognized by a monospecific antirabies virus nucleoprotein antiserum on paraffin sections of formalin-fixed tissues.

Diagnosis of rabies is routinely confirmed by detection of rabies virus antigens in acetone-fixed frozen brain tissues or imprint smears using an immunofluorescence method with commercial antirabies virus antibodies. Since recent molecular analyses disclosed wide heterogeneity in the genome sequences of rabies virus strains and related lyssaviruses, it is necessary to confirm the presence of common epitopes in these lyssaviruses. In this study we confirmed the presence of cross-reactive antigens of various lyssaviruses in paraffin sections of formalin-fixed tissue using a monospecific rabbit antiserum prepared by immunization with a recombinant nucleoprotein of rabies virus. By immunohistochemical application, the antigen was detected predominantly in the cytoplasm of neurons in the brains of mice infected with rabies virus, Duvenhage virus, Mokola virus and European bat lyssavirus-1, while no cross-reaction was observed in uninfected humans and animals including dogs, bats, and raccoons. In addition, we examined one autopsy case that was infected in a rabies-endemic nation and developed the clinical manifestation of rabies after returning to Japan in 1970, and found that the antigen was well preserved in paraffin sections of formalin-fixed tissues. Thus, this suggests that the lyssavirus-specific antigen is recognized by the monospecific antibody against rabies virus nucleoprotein, and that this cross-reactive antigen is detectable on formalin-fixed paraffin-embedded tissues by immunohistochemical analysis.

Amino Acid Sequence↗
PubMed2003

Autonomic function in Kawasaki disease with myocardial infarction: usefulness of monitoring heart rate variability.

BACKGROUND: Despite anticoagulant therapy, many patients with Kawasaki disease and giant coronary artery aneurysm develop myocardial infarction. These patients have a high risk of sudden death, but the etiology is not clear. We studied autonomic function and the possibility of malignant ventricular arrhythmia through heart rate variability. METHODS: We studied six Kawasaki disease patients with myocardial infarction and 16 normal controls. Heart rate variability was investigated using a 24 h electrocardiogram. We assessed the standard deviation from the mean of the normal R-R intervals (SDNN), the proportion of adjacent R-R intervals with a difference greater than 50 msec (pNN50) and the root-mean square of successive R-R differences as time-domain analysis (rMSSD). We assessed very low-frequency power, low-frequency power (LF), high-frequency power (HF) and the LF/HF ratio in frequency-domain analysis. RESULTS: There was no significant difference in SDNN, but there was a significant difference in pNN50 and rMSSD. Patients with Kawasaki disease showed lower HF and higher LF/HF than normal controls. CONCLUSION: Our findings suggest that patients with Kawasaki disease and myocardial infarction show decreased vagal activity, which could cause malignant arrhythmia.

Adolescent↗
PubMed2003

A simple controlled-rate freezing method without a rate-controlled programmed freezer provides optimal conditions for both large-scale and small-scale cryopreservation of umbilical cord blood cells.

BACKGROUND: Umbilical cord blood (CB) is being used as a source of alternative HPCs for transplantation with increasing frequency. The goal of CB banks for unrelated transplantation is to provide good quality-controlled CB units that can be transplanted for HPCs into the largest possible number of patients. STUDY DESIGN AND METHODS: Large CB samples in freezing bags wrapped with insulators and small samples in cryotubes placed into double styrene-foam boxes were cryopreserved at -85 degrees C without a rate-controlled freezing machine, followed by storage in the liquid phase of nitrogen. After thawing these cells, the viability and recovery of cells, as well as the recovery rate of HPCs such as CD34+ cells, CFU-GM, and total CFU were evaluated. RESULTS: Measurement of the freezing rate in CB bags and cryotubes demonstrated that this simple method for cryopreservation of CB cells provided optimal conditions for both large-scale and small-scale cryopreservation. Recovery of CB progenitor cells after cryopreservation was also shown to be potentially acceptable when evaluated with CD34+ cells, CFU-GM, and total CFU. These results were comparable to the method using a rate-controlled programmed freezer. CONCLUSIONS: A simple method for cryopreservation of CB cells without a rate-controlled programmed freezer could provide a sufficient-enough potential for the transplantability of HPCs after thawing.

Blood Banks↗
PubMed2003

Positive and negative effects of adeno-associated virus Rep on AAVS1-targeted integration.

Adeno-associated virus type 2 integrates preferentially into the AAVS1 locus on chromosome 19 of the human genome. It was reported previously that transfection with two plasmids, one for Rep and the other carrying a transgene flanked by inverted terminal repeats (ITRs), enables preferential integration of the latter into AAVS1. Aiming at increasing the frequency of AAVS1-specific integration, the Rep- to transgene-plasmid ratio necessary to achieve a higher frequency of site-specific integration was examined. 293 cells were co-transfected with the Rep78 plasmid and an ITR-flanked Neo gene at different ratios. G418-resistant clones were selected randomly. Extensive Southern blot analysis showed an optimum range of Rep78 expression. In that range, approximately 20 % of clones harboured the Neo gene at AAVS1. Excess Rep expression, however, resulted in 'abortive' integration of the Neo gene, a rearrangement of AAVS1 without transgene integration. Rep78 appeared to cause abortive integration more extensively than Rep68. Deleterious effects of the Rep protein on the AAVS1 locus should be considered to develop an improved AAVS1-targeted system.

Cell Line↗
PubMed2003

The absolute number of peripheral blood CD34+ cells predicts a timing for apheresis and progenitor cell yield in patients with hematologic malignancies and solid tumors.

Retrospective analysis was conducted in 51 autologous peripheral blood progenitor cell (PBPC) collections using the Spectra AutoPBSC System from patients with hematologic malignancies and solid tumors to study the predictive value of CD34+ cell counts in the peripheral blood for the yield of CD34+ cells in the apheresis product. The correlation coefficients for CD34+ cells microL(-1) of peripheral blood with CD34+ cell yield (x 10(6) kg(-1) of body weight and x 10(5) kg(-1) of body weight L(-1) of blood processed) were 0.903 and 0.778 (n=51 collections), respectively. Products collected from patients with CD34+ cell counts below 15 microL(-1) in the peripheral blood contained a median of 0.49 x 10(6) CD34+ cells kg(-1) (range: 0.05-2.55), whereas those with CD34+ cell counts more than 15 microL(-1) contained a median of 3.72 x 10(6) CD34+ cells kg(-1) (range: 1.06-37.57). From these results, a number of at least 15 CD34+ cells microL(-1) in the peripheral blood ensured a minimum yield of 1 x 10(6) CD34+ cells kg(-1) as obtained by a single apheresis procedure. The number of CD34+ cells in the peripheral blood can be used as a good predictor for timing of apheresis and estimating PBPC yield. With regard to our results, apheresis with a possibly poor efficiency should be avoided because the collection procedure is time-consuming and expensive.

Adolescent↗
PubMed2003

Effects of overexpression of the Ets family transcription factor TEL on cell growth and differentiation of K562 cells.

Functional roles of several Ets transcription factors in megakaryocytic and erythroid differentiation of the human chronic myelogenous leukemia cell line K562 was investigated. When K562 cells were induced to differentiate into the megakaryocyte lineage by treatment with TPA, the expression of the c-ets-1, Fli-1 and TEL2 genes was increased, and that of the TEL gene was decreased at the onset of differentiation. When the cells were induced to differentiate into the erythroid lineage by treatment with Hemin, expression of the c-ets-1 gene was increased, and that of the Fli-1 and TEL genes was decreased. To investigate the role of TEL in the growth and differentiation of K562 cells, we introduced an expression plasmid containing the TEL gene into the cells. Overexpression of TEL in K562 cells leads to inhibition of the endogenous expression of megakaryocyte-specific GPIIb and GPIbalpha genes, and inhibition of cell growth. DNA array analysis revealed that expression of genes such as the RhoG and D4-GDI genes was down-regulated in TEL-overexpressing cells, while that of the representative growth-related genes such as the c-myc, c-fos and c-jun genes was not remarkably changed. These results suggest that several Ets family transcription factors are implicated in megakaryocytic and erythroid differentiation of K562 cells and TEL inhibits the expression of some megakaryocyte-specific genes and growth in K562 cells.

Base Sequence↗
PubMed2002

Transformation of Ba/F3 cells and Rat-1 cells by ETV6/ARG.

ETV6/ARG, a novel fusion gene composed of the ETV6 HLH oligomerization domain and most of sequences of the ARG protein tyrosine, was recently identified in human leukemia cells. The presence of the ETV6/ARG translocation raises the possibility that the resulting fusion protein functions as an oncogene. However, the transforming activity of the ETV6/ARG protein has not been determined and its contribution to leukemogenesis is therefore unknown. Here we address this question by analysing the oncogenic activity of ETV6/ARG in hematopoietic and fibroblast cells. It is demonstrated that expression of ETV6/ARG confers IL3-independent growth to Ba/F3 cells and anchorage independent growth to Rat-1 fibroblasts. It is also shown that multiple signaling molecules, including PI3K, SHC, ras-GAP and CRK-L, are tyrosine phosphorylated in Ba/F3 cells that express ETV6/ARG. Analysis of four different types of ETV6/ARG transcripts previously identified in the AML-M3 leukemia cell line HT93A suggest that ETV6 HLH domain is required for oncogenic activity. Based upon these results it is concluded that ARG can be activated as an oncogene in human malignancy and that the ETV6/ARG oncoprotein triggers some of the same signaling pathways associated with activated ABL oncogenes.

Animals↗
PubMed2002

Protection against influenza virus infection in polymeric Ig receptor knockout mice immunized intranasally with adjuvant-combined vaccines.

The role of secretory IgA in conferring cross-protective immunity was examined in polymeric (p)IgR knockout (KO) mice immunized intranasally with different inactivated vaccines prepared from A/PR/8/34 (H1N1), A/Yamagata/120/86 (H1N1), A/Beijing/262/95 (H1N1), and B/Ibaraki/2/85 viruses and infected with the A/PR/8/34 virus in the upper respiratory tract (RT)-restricting volume. In wild-type mice, immunization with A/PR/8/34 or its variant (A/Yamagata/120/86 and A/Beijing/262/95) vaccines conferred complete protection or partial cross-protection against infection, while the B-type virus vaccine failed to provide protection. The protection or cross-protection was accompanied by an increase in the nasal A/PR/8/34 hemagglutinin-reactive IgA concentration, which was estimated to be >30 times the serum IgA concentration and much higher than the nasal IgG concentration. In contrast, the blockade of transepithelial transport of dimeric IgA in pIgR-KO mice reduced the degree of protection or cross-protection, in parallel with the marked increase in serum IgA concentration and the decrease in nasal IgA concentration (about 20 and 0.3 times those in wild-type mice, respectively). The degree of the reduction of protection or cross-protection was moderately reversed by the low but non-negligible level of nasal IgA, transudates from the accumulated serum IgA. These results, together with the absence of the IgA-dependent cross-protection in the lower RT and the unaltered level of nasal or serum IgG in wild-type and pIgR-KO mice, confirm that the actively secreted IgA plays an important role in cross-protection against variant virus infection in the upper RT, which cannot be substituted by serum IgG.

Adjuvants, Immunologic↗
PubMed2002

Regulation of cerebral cortical blood flow by the basal forebrain cholinergic fibers and aging.

This article reviews the study of neural vasodilator mechanisms of the cerebral cortex by basal forebrain cholinergic nerve fibers and their age-related function in rats. During the last decade, we have demonstrated a neural regulatory system of cerebral blood flow in rats involving intracerebral cholinergic vasodilator nerve fibers originating in the basal forebrain and projecting to the cerebral cortex. Activation of these cholinergic vasodilator fibers results in the release of acetylcholine (ACh) within the cortex, activation of both nicotinic and muscarinic ACh receptors, and vasodilatation without coupling to glucose metabolic rates. This cholinergic vasodilator system has been shown to decline with age in rats mainly due to age-related declines of nicotinic ACh receptor activity. However, muscarinic ACh receptor activity and the release of ACh into the extracellular space in the cortex are well maintained during aging. The present age-related decline of the intracerebral cholinergic vasodilator system found in rats seems to affect cognitive function during aging, although this cholinergic vasodilator system has not yet been demonstrated in humans.

Aging↗
PubMed2002

Expression of the TEL/EVI1 fusion transcript in a patient with chronic myelogenous leukemia with t(3;12)(q26;p13).

The t(3;12)(q26;p13) translocation is a recurrent chromosomal aberration observed in myeloid malignancies. It has been shown that the translocation results in the fusion of the TEL (ETV6) gene at 12p13 and the EV11 gene at 3q26. We report the first case with Philadelphia (Ph)-positive chronic myelogenous leukemia (CML) expressing the TEL/EVI1 fusion transcript. A 26-year-old man was initially diagnosed as having the chronic phase of Ph-positive CML. The t(3;12)(q26;p13) emerged 16 months prior to the myeloid blastic crisis. Reverse transcriptase-polymerase chain reaction detected the TEL/EVI1 transcript without the intervening 5' non-coding exon of EVI1, suggesting that inappropriate expression of the EVI1 protein driven by the TEL promotor could play a critical role in progression to the blast crisis of CML.

Adult↗