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Biomedical subjects

M Eguchi

Publications and source records attributed to M Eguchi.

At least 19 recordsLinked to original sources
PubMed2001

Evidence for the presence of murine primitive megakaryocytopoiesis in the early yolk sac.

During mouse embryogenesis, primitive erythropoiesis occurs in blood islands of the yolk sac (YS) on the seventh day of gestation. This study demonstrated for the first time the presence of unique primitive megakaryocytic (Mk) progenitors in the early YS, which disappeared by 13.5 days postcoitum (dpc). When 7.5 dpc YS cells were incubated in the presence of stem cell factor (SCF), interleukin (IL)-3, IL-6, erythropoietin (EPO), thrombopoietin (TPO), and granulocyte colony-stimulating factor in methylcellulose clonal culture, not only erythroid bursts but also megakaryocyte colonies were observed. The megakaryocytes in the colonies matured to proplatelet stages and produced platelets as early as day 3 of culture, much earlier than those from adult bone marrow, although their ploidy class was lower. These megakaryocytes were stained with acetylcholine esterase, and expressed platelet glycoprotein (GP)Ib beta, GPIIIa, and platelet factor 4 by reverse transcription-polymerase chain reaction analysis. The analysis of hemoglobin types in erythrocytes obtained from hematopoietic multilineage colonies containing the megakaryocytes indicated that the Mk progenitors originated from primitive hematopoiesis. The primitive Mk progenitors formed colonies in the absence of any cytokines in fetal bovine serum (FBS)-containing culture, and SCF, IL-3, EPO, and TPO significantly enhanced the Mk colony formation. In FBS-free culture, however, no colony formation was induced without these cytokines. Because megakaryocytes were detected in 8.5-dpc YS, these unique primitive Mk progenitors may rapidly mature and give rise to platelets to prevent hemorrhage in the simultaneously developing blood vessels until definitive hematopoiesis begins to produce platelets. (Blood. 2001;97:2016-2022)

Animals↗
PubMed2001

Breakage and fusion of the TEL (ETV6) gene in immature B lymphocytes induced by apoptogenic signals.

TEL-AML1 fusion resulting from the t(12;21)(p13;q22) is one of the most common genetic abnormalities in childhood acute lymphoblastic leukemia. Recent findings that site-specific cleavage of the MLL gene can be induced by chemotherapeutic agents such as topoisomerase-II inhibitors suggest that apoptogenic agents can cause chromosomal translocations in hematopoietic cells. This study demonstrates a possible relationship between exposure to apoptogenic stimuli, TEL breaks, and the formation of TEL-AML1 fusion in immature B lymphocytes. Short-term culture of immature B cell lines in the presence of apoptogenic stimuli such as serum starvation, etoposide, or salicylic acid induced double-strand breaks (DSBs) in intron 5 of the TEL gene and intron 1 of the AML1 gene. TEL-AML1 fusion transcripts were also identified by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis in cell lines treated by serum starvation or aminophylline. DSBs within the TEL gene were also associated with fusion to other unknown genes, presumably as a result of chromosomal translocation. We also examined 67 cord blood and 147 normal peripheral blood samples for the existence of in-frame TEL-AML1 fusion transcripts. One cord blood sample (1.5%) and 13 normal peripheral blood samples (8.8%) were positive as detected by nested RT-PCR. These data suggest that breakage and fusion of TEL and AML1 may be relatively common events and that sublethal apoptotic signals could play a role in initiating leukemogenesis via the promotion of DNA damage.

Aminophylline↗
PubMed2001

Restricted chromosome breakpoint sites on 11q22-q23.1 and 11q25 in various hematological malignancies without MLL/ALL-1 gene rearrangement.

We analyzed 32 patients with various hematological malignancies including acute myelocytic leukemia and non-Hodgkin lymphoma with a breakpoint at 11q22-q25 of chromosome 11, but who did not have rearrangements of the MLL/ALL-1 gene. The breakpoint in each patient was identified by fluorescence in situ hybridization using 21 cosmid probes and 2 YAC probes. Breakpoints for each "rearrangement" involving translocations such as t(1;11), t(2;11), inv(11), t(11;15), and t(10;11) found in 5 of the 11 patients had breakpoints in a small region from Ccl11-430 to Ccl11-526 at 11q22-q23.1. Furthermore, breakpoints for chromosome deletions at 11q21-q23 in 10 patients were located in the same region as that of translocations. A commonly deleted region among 8 patients was identified from Ccl11-526 to Ccl11-555 at 11q23.1. Fluorescence in situ hybridization analysis revealed that breakpoints for additive chromosome [add(11)] aberrations, which had additional material of unknown origin at 11q23 to 11q25 in 11 patients, were not located at 11q23 but rather at the more telomeric site of Ccl11-503 to VIJ(2)2072 at 11q25. These results indicated that the patients had several restricted breakpoint sites, which means that these chromosomal regions have recurrent oncogenes and tumor suppressor genes for pathogenesis for leukemia and lymphoma.

Acute Disease↗
PubMed2001

Electron microscopic and cytochemical studies of peroxidase-negative acute nonlymphoblastic leukemia.

Cytochemical and ultrastructural studies of 42 patients with acute nonlymphoblastic leukemia (ANLL) lacking myeloperoxidase as detected by light microscopy were performed. These ANLL patients were classified into minimally differentiated acute myeloid leukemia (AML-M0) (26 cases), mixed-lineage leukemia (9 cases), and acute undifferentiated leukemia (AUL) (7 cases). Ultrastructural morphology revealed blasts from AML-M0 as very immature myeloid cells, blasts from mixed-lineage leukemia as having partially lymphoid cell features, and blasts from AUL as undifferentiated blasts with myeloid nature to some extent. Ultrastructurally, myeloperoxidase activity was positive in 81% of AML-M0 patients and less positive in the mixed-lineage leukemia and AUL patients. The DNA in the nuclei of the AML-M0 blasts was dispersed, as was observed in the immature myeloid cells. Some of the blasts from the mixed-lineage leukemia patients showed condensation of DNA, resembling blasts from acute lymphoblastic leukemia (ALL). The distribution of periodate-reactive glycoconjugates revealed that glycogen particles were absent or, if present, very scanty in AML-M0. Most of the blasts from the AUL patients lacked glycogen particles, and the blasts from those with mixed-lineage leukemia contained clustered glycogen particles, as was observed in the blasts from all patients. These findings disclosed that three subtypes of immature ANLL showed different cytochemical and ultrastructural features in accordance with their immunophenotypical classification.

Adolescent↗
PubMed2001

A field evaluation of in situ biodegradation of trichloroethylene through methane injection.

A field study of biodegradation of trichloroethylene (TCE) through methane injection was conducted at the yard of a home in Japan. Methane was selected as the safest substrate for injection into groundwater. Methane, oxygen, nitrate, and phosphate were introduced into groundwater contaminated with 220 microg/L of TCE. After a week of biostimulation, methane concentrations gradually decreased below the detection limit. Methane oxidizing bacterial numbers increased from 10 to 10(4) cells/mL with methane consumptions. During methane injection. 10-20% of TCE removal was observed. The biotransformation yield was 3-13 mgTCE/gCH4 in this field test. After methane injections were stopped, TCE removal was not observed. These results indicated that bioremediation using methane was useful as a safe technology for a TCE-contaminated area near homes.

Biodegradation, Environmental↗
PubMed2001

Oligoclonal expansion of alphabeta T lymphocytes in Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis with abnormal karyotypes.

We observed a fatal case of Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (HLH) with an abnormal karyotype. Increased levels of alphabeta T cells of the patient were investigated using an inverse polymerase chain reaction (PCR) of the T-cell receptor variable region gene, followed by Jbeta-PCR and single-strand conformation polymorphism (SSCP) to confirm the clonality of specific alphabeta-T cell subsets. A high frequency (>15%) was recognized in Vbeta9 at onset, but not in any Vbeta and Valpha families 2 weeks after chemotherapy. High levels (>20%) of some Jbeta genes were detected in all Vbeta families investigated, and the predominant bias of the Jbeta2 gene relative to the Jbeta1 gene (86.1% versus 13.9% at onset, and 77.4% versus 23.5% after chemotherapy) was recognized in pan-alphabeta T cells. When each Vbeta-Jbeta fragment was compared among the samples at onset and after chemotherapy by SSCP analysis, several distinct bands were observed that indicate a clonal evolution. Thus, the findings suggest that some of the alphabeta T cell clones could be associated with abnormal karyotypes in EBV-HLH. The present findings provide molecular evidence of the presence of oligoclonal T cells in pan-alphabeta-T cells and clonal evolution during a short clinical course in EBV-HLH with abnormal karyotypes.

Child↗
PubMed2001

Effect of constitutively expressed phoP gene on the localization of Salmonella typhimurium within Mac-1 positive phagocytes.

Intracellular localization of the wild-type (Spv+), the phoP-constitutively expressed strain (PhoPc), and the spv-deleted strain (Spv-) of Salmonella typhimurium was examined by the use of confocal laser scanning microscopy analysis of immunostained sections of mouse spleens after oral or subcutaneous inoculation. Only 40% of salmonellae of both the PhoPc and the Spv- strains were detected intracellularly within Mac-1 positive cells at day five after oral or day four after subcutaneous inoculation. In contrast, over 85% of salmonellae of the Spv+ strain were detected inside Mac-1 positive cells. In both inoculation trials, the splenic colony-forming unit values for the PhoPc and Spv- strains were significantly lower than the corresponding value for the Spv+ strain. These findings suggest that the constitutively expressed phoP gene of S. typhimurium attenuated virulence by limiting intracellular proliferation within mouse spleen phagocytes, and that the lack of spv genes had the same effect.

ADP Ribose Transferases↗
PubMed2000

Right ventricular abnormalities assessed by myocardial single-photon emission computed tomography using technetium-99m sestamibi/tetrofosmin in right ventricle-originated ventricular tachyarrhythmias.

OBJECTIVES: We sought to determine whether right ventricular (RV) perfusion imaging with technetium-99m (Tc-99m) sestamibi or tetrofosmin single-photon emission computed tomography has diagnostic benefit for RV-originated ventricular tachyarrhythmias (RVT). BACKGROUND: Identification of RV abnormalities is clinically important to establish RVT etiology. METHODS: Forty-seven patients with RVT (23 with idiopathic and 24 with organic RVT due to arrhythmogenic RV or dilated cardiomyopathy, cardiac sarcoidosis or myocarditis) were compared to 25 control subjects. Right ventricular uptake score, as assessed by modified tomographic imaging, and regional RV count relative to peak left ventricular (LV) count (RV/LV count ratio) were compared with RV regional and global function. RESULTS: Regional RV uptake score correlated well with the RV/LV count ratio, and segmental abnormality was more frequently (p = 0.001) detected in the organic RVT group (22 [92%] of 24 patients) than in the idiopathic RVT group (4 [17%] of 23 patients) or the control group (8 [32%] of 25 patients). The total RV score (8.4+/-3.8) in the organic RVT group was significantly lower than that in the idiopathic RVT group (15.6+/-1.6) or the control group (15.1+/-1.8). The total RV score correlated with RV EF (r = 0.702, p<0.001). A total RV score <12 differentiated the organic RVT group from the other two groups, with a sensitivity of 79% and a specificity of 100%. The asynergic RV regions had a significantly lower RV/LV count ratio and RV score as compared with the nonasynergic regions and were identified by RV assessment, with a sensitivity of 76.1% and a specificity of 76.6%. CONCLUSIONS: Right ventricular perfusion tomography using a Tc-99m-labeled tracer is clinically useful for the noninvasive detection of RV myocardial damage in patients with RVT and for differentiating organic from idiopathic RVT.

Adolescent↗
PubMed2000

Enhanced GAP-43 gene expression in cortical dysplasia.

Growth-associated protein GAP-43, a phosphoprotein enriched at presynaptic nerve terminals, is thought to be involved in axonal outgrowth and plasticity in synaptic connections. To explore the synaptic remodeling under the epileptic conditions, we examined GAP-43 expression in brain specimens surgically resected as epileptogenic foci from 17 patients with cortical dysplasia. In situ hybridization with GAP-43 antisense riboprobe showed significantly increased signals in the dysplastic large neurons of cortical dysplasia. Specific distribution with increased immunoreactivity for GAP-43 was not shown in the dysplastic cortex. These results suggest that GAP-43 gene expression is over-expressed in the dysplastic large neurons, reflecting activated synaptic remodeling in the epileptic condition of cortical dysplasia, although the precise site of accelerated synaptic rearrangement remains unknown.

Cerebral Cortex↗
PubMed2000

Genomic imprinting of insulin-like growth factor-2 in infant leukemia and childhood neuroblastoma.

BACKGROUND: Loss of imprinting (LOI) of insulin-like growth factor-2 (IGF-2) has been implicated in the pathogenesis of certain human cancers and tumor-predisposing overgrowth disorders, such as Beckwith-Wiedemann syndrome. In a previous study, the authors revealed that certain patients with childhood acute leukemia and neuroblastoma had had rapid somatic growth after birth, suggesting the involvement of growth factor(s) in tumorigenesis. In the current study, the authors examined whether relaxation of IGF-2 imprinting occurred in infant leukemia and childhood neuroblastoma. METHODS: The genomic DNA of infant leukemia, childhood neuroblastoma, and control individuals was amplified by polymerase chain reaction (PCR). Patients who had heterozygous genotype were selected as informative cases using Apa I polymorphism in exon 9 of the IGF-2 gene. Total RNA was isolated from informative cases, followed by cDNA synthesis. cDNA was amplified by PCR, and direct sequence was performed for determining allele specific transcription. RESULTS: Twenty of 22 infant leukemia blasts and all of 16 neuroblastoma cells showed normal monoallelic expression of IGF-2 as well as 23 controls. The height and weight of two acute lymphoblastic leukemia patients with LOI were within normal ranges for Japanese children. CONCLUSIONS: The current study revealed that the imprinting status of IGF-2 was generally maintained in infant leukemia and confirmed that it was maintained in childhood neuroblastoma. The results suggest that LOI of IGF-2 does not play a major role in the carcinogenesis of these diseases or in rapid physical growth of the patients.

Female↗
PubMed2000

Monitoring impact of in situ biostimulation treatment on groundwater bacterial community by DGGE.

Changes in bacterial diversity during the field experiment on biostimulation were monitored by denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rDNA fragments. The results revealed that the bacterial community was disturbed after the start of treatment, continued to change for 45 days or 60 days and then formed a relatively stable community different from the original community structure. DGGE analysis of soluble methane monooxygenase (sMMO) hydroxylase gene fragments, mmoX, was performed to monitor the shifts in the numerically dominant sMMO-containing methanotrophs during the field experiment. Sequence analysis on the mmoX gene fragments from the DGGE bands implied that the biostimulation treatment caused a shift of potential dominant sMMO-containing methanotrophs from type I methanotrophs to type II methanotrophs.

Journal Article↗
PubMed2000

A new ETV6/TEL partner gene, ARG (ABL-related gene or ABL2), identified in an AML-M3 cell line with a t(1;12)(q25;p13) translocation.

The ETV6/TEL gene has been reported to fuse to PDGFRbetab MDS1/EVI1, BTL, ACS2, STL, JAK2, ABL, CDX2, TRKC, AML1, and MN1. Among them, PDGFRbeta, ABL, JAK2, and TRKC are tyrosine kinases (TK). We identified a novel ETV6 partner gene, ARG (ABL-related gene or ABL2), another TK gene in a cell line established from a patient with acute myelogenous leukemia (AML-M3) with a t(15;17)(q22;q11.2) and a t(1;12)(q25;p13), which has the remarkable feature to differentiate to mature eosinophils in culture with all-trans retinoic acid and cytokines. The ETV6/ARG transcripts consisted of exon 1 to 5 of ETV6 and the 3' portion of ARG starting from exon 1B or exon 2, resulting in an open reading frame for a fusion protein consisting of the entire PNT oligomerization domain of ETV6 and all of the functional domains of ARG including the TK domain. This is the same protein structure as identified in the other ETV6 TK fusion proteins. The reciprocal ARG/ETV6 transcript was not expressed, and the normal ETV6 allele was not deleted or rearranged. Although the ABL is known to be involved in various human malignancies, ARG has not been involved in human malignancies despite its high homology to ABL. Thus, this is the first report showing involvement of ARG in human leukemia. The ETV6/ARG protein may be involved in the unique differentiation capacity of this cell line. (Blood. 2000;95:2126-2131)

Adaptor Proteins, Signal Transducing↗
PubMed2000

Large deletion of the X-linked lymphoproliferative disease gene detected by fluorescence in situ hybridization.

The X-linked lymphoproliferative disease (XLP) is an inherited immunodeficiency characterized by an abnormal responses to infection with Epstein-Barr virus (EBV), resulting in fatal infectious mononucleosis, hypogammaglobulinemia, virus-associated hemophagocytic syndrome, and malignant lymphoma. Mutations in the gene coding for a T cell-specific SLAM-associated protein (SAP) have been recently identified in XLP patients. We report on a 1-year-old boy representing fulminant hemophagocytic syndrome. He developed high fever, lymphadenopathy, hepatosplenomegaly with liver dysfunction, and pancytopenia with marrow hemophagocytosis. EBV DNA was abnormally increased in the blood. Polymerase chain reaction failed to amplify SAP mRNA and genomic DNA products from the patient' As peripheral blood. A large deletion of the SAP gene was confirmed by fluorescence in situ hybridization (FISH). FISH analysis also disclosed that the patient's mother was a carrier. We conclude that FISH can be useful in the diagnosis of XLP with large deletions of the SAP gene and its carrier state.

Carrier Proteins↗
PubMed2000

Use of confocal microscopy to detect Salmonella typhimurium within host cells associated with Spv-mediated intracellular proliferation.

The major limitation in histological examination of orally inoculated mice of Salmonella typhimurium has been the difficulty of attaining high enough levels for immunochemical detection. This problem has been solved by the use of confocal laser scanning microscopy (CLSM) analysis, which allows detection of bacteria in the immunostained sections of mouse spleens at a minimum rate of approximately 1000 colony-forming units (cfu)/spleen. Here, we demonstrate that over 80% of salmonellae of the wild type of S. typhimurium were detected intracellularly within Mac-1 positive cells by the CLSM analysis of immunostained sections from spleens in orally or subcutaneously inoculated mice. Only 40% of salmonellae of the spv -deleted strain were detected inside Mac-1 positive cells. These data suggest that the spv genes play a key role in intracellular proliferation within phagocytes in the mouse spleen.

Animals↗
PubMed2000

An effective chemotherapeutic regimen for acute myeloid leukemia and myelodysplastic syndrome in children with Down's syndrome.

In recent pediatric collaborative studies of acute myeloid leukemia (AML), patients with Down's syndrome (DS) have better outcome than other patients when they were treated according to their intensive AML protocols. This may be attributed to enhanced sensitivity of DS AML cells to selected chemotherapeutic agents. We evaluated a less intensive chemotherapeutic regimen which was specifically designed for children with AML-DS. Remission induction chemotherapy consisted of daunorubicin (25 mg/m2/day for 2 days), cytosine arabinoside (100 mg/m2/day for 7 days), and etoposide (150 mg/m2/day for 3 days). Patients received one to seven courses of consolidation therapy of the same regimen. Thirty-three patients were enrolled on the study and their clinical, hematologic and immunophenotypic features were analyzed. Of the 33 patients, all were younger than 4 years and diagnosed as having acute megakaryoblastic leukemia or myelodysplastic syndrome. All patients achieved a complete remission and estimated 8 year event-free survival rate was 80+/-7%. Three patients relapsed and two died due to cardiac toxicity and one due to septic shock. The results of our study showed that patients with AML-DS constitute a unique biologic subgroup and should be treated according to a less intensive protocol designed for AML-DS.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Technetium-99m sestamibi/tetrofosmin myocardial perfusion scanning in cardiac and noncardiac sarcoidosis.

Left ventricular (LV) and right ventricular (RV) involvement in sarcoidosis must be firmly confirmed to determine patients' prognosis. We examined whether myocardial perfusion images using technetium-99m single photon emission computed tomography (SPECT) have a diagnostic benefit in the evaluation of biventricular involvement. Sixteen patients with sarcoidosis, aged 21-78 (54 +/- 12) years old, 5 males and 11 females, complicated with cardiac disease (cardiac sarcoidosis, n = 6) including tachyarrhythmias of ventricular origin (n = 5), atrioventricular block (n = 4), and congestive heart failure (NYHA > or = II, n = 1), were enrolled in this study. Myocardial SPECT using technetium-99m sestamibi or tetrofosmin was performed and semiquantitatively scored for comparison with 25 control subjects. Perfusion abnormalities were more frequently recognized in sarcoidosis (LV 5/16, 31% and RV 14/16, 88% vs. LV 0/25, 0% and RV 8/25, 32% in controls). LV involvement had a close correlation with atrioventricular block and with congestive heart failure, and multiple sites of RV involvement correlated with ventricular tachyarrhythmia of RV origin. Total number of defect segments were highest in cardiac sarcoidosis (18/30, 60% vs. 19/60, 32% in noncardiac sarcoidosis, and 11/150, 7% in controls, p = 0.0001), and semiquantitatively evaluated total LV and RV scores (ranging from 0 to 18) were higher than those of controls (15.1 +/- 1.8 vs. 11.4 +/- 3.0 in noncardiac sarcoidosis, and 9.0 +/- 5.0 in cardiac sarcoidosis) and exhibited a significant positive linear correlation with the RV ejection fraction (y = 19.8 + 1.83x, r = 0.786, p = 0.001). Biventricular SPECT using technetium-99m is clinically useful for the noninvasive evaluation of both ventricular involvements in sarcoidosis.

Adult↗