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Biomedical subjects

K Takenaka

Publications and source records attributed to K Takenaka.

At least 37 records · Page 2Linked to original sources
PubMed2001

Severe bleeding tendency caused by leukemic infiltration and destruction of vascular walls in chronic neutrophilic leukemia.

Bleeding is reportedly one of the major causes of death in patients with chronic neutrophilic leukemia (CNL), but thrombocytopenia, abnormal platelet functions, or coagulopathy has been confirmed to be the cause of the bleeding tendency in only a small proportion of the patients. We report the case of a 49-year-old woman with CNL who experienced episodes of cutaneous and recurrent multiple cerebral hemorrhages without severe thrombocytopenia, detectable abnormal platelet functions, or coagulating dysfunction. Histological examination of specimens obtained at autopsy showed extensive infiltration and destruction of vascular walls by leukemic cells, which could explain her severe bleeding tendency. This study is the first to clearly show that the infiltration and destruction of vascular walls by leukemic cells can cause fatal bleeding episodes without warning from laboratory findings. Further studies are needed to elucidate the mechanism of the infiltration and destruction of blood vessels by CNL cells and to develop effective measures to control the growth and infiltration of CNL cells.

Endothelium, Vascular↗
PubMed2001

Cytomegalovirus enteritis after autologous peripheral blood stem cell transplantation.

A 61-year-old male with non-Hodgkin's lymphoma (peripheral T-cell lymphoma, unspecified, clinical stage IVb) received autologous peripheral blood stem cell transplantation (PBSCT) during first remission. He was seropositive for cytomegalovirus (CMV) prior to autologous PBSCT. His posttransplant clinical course was complicated by refractory CMV enteritis, which manifested persistent abdominal pain, diarrhea, and bloody stool. Generally, gastrointestinal CMV disease is relatively rare after autologous PBSCT. However, our case indicates that CMV infection must be considered as a differential diagnosis in cases of unexplained hemorrhagic enteritis following autologous PBSCT.

Abdominal Pain↗
PubMed2001

Chromosome analysis after ex vivo expansion of CD34(+) cells from human cord blood.

Ex vivo expansion of cord blood hematopoietic progenitors is an attractive way to prepare a sufficient number of transplantable cells for cord blood transplantation in adult patients. The expanded cells need to have genetic stability. Karyotypic analysis of the expanded cells from cord blood CD34(+) cells by 7-day culture with stem cell growth factor, interleukin (IL)-3, IL-6, granulocyte colony-stimulating factor, and erythropoietin was performed. Several-fold increases in total cell number and CFU-GM were 186.7 +/- 62.1 and 27.1 +/- 9.4 (mean +/- standard deviation of data from 6 samples), respectively. Karyotypes were analyzed in 600 expanded cells in total, and all of them showed normal karyotypes. This observation suggests that multifactor supported expansion of cord blood cells may not induce karyotypic abnormality, although a limited number of ex vivo expanded cells were tested.

Antigens, CD34↗
PubMed2001

Administration of granulocyte colony-stimulating factor induces hyporesponsiveness to lipopolysaccharide and impairs antigen-presenting function of peripheral blood monocytes.

OBJECTIVE: The incidence and severity of acute graft-vs-host disease after allogeneic transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (PBSC) are not greater than those after conventional bone marrow transplantation despite infusion of more than one log greater number of donor T cells in PBSC. It has been postulated that monocytes from G-CSF-mobilized donors suppress alloreactivity of donor T cells. MATERIALS AND METHODS: We investigated the phenotype and function of monocytes in normal individuals receiving 10 microg/kg of G-CSF for 4 days. RESULTS: Monocytes were phenotypically and functionally different after G-CSF administration from steady-state monocytes. They were characterized by an increased CD14(+)CD16(+) subpopulation, reduced expression of HLA-DR, and diminished ability to produce tumor necrosis factor-alpha and interleukin-10 to lipopolysaccharide, compared with steady-state monocytes. These alterations were not replicated by culturing monocytes with G-CSF in vitro, suggesting an indirect effect of G-CSF. In addition, the antigen-presenting function of G-CSF-mobilized monocytes was impaired. CONCLUSION: Hyporesponsiveness of G-CSF-treated monocytes to lipopolysaccharide with regard to tumor necrosis factor-alpha production, together with impaired antigen-presenting function, may be responsible for the unexpectedly low incidence of graft-vs-host disease after G-CSF-mobilized PBSC transplantation.

Antigen Presentation↗
PubMed2001

Altered expression of several genes in highly metastatic subpopulations of a human pulmonary adenocarcinoma cell line.

Non-small cell lung cancer is associated with approximately 85% mortality due to its high metastatic potential. Therapeutic efforts have failed to produce a significant improvement in prognosis. In this situation, a better understanding of the key factors of metastasis may be useful for designing new molecular targets of therapy. In order to identify these factors, we compared the expression profiles of two subpopulations of an adenocarcinoma cell line with a high metastatic potential, PC9/f9 and PC9/f14, with the parent cell line, PC9, using a cDNA array. The expression of 15 genes was found to be significantly enhanced or reduced in the highly metastatic subpopulations. The expression of matrix metalloproteinase-2 (MMP-2), plasminogen activator inhibitor-1 (PAI-1) and interleukin-1 (IL-1 alpha) were upregulated in the highly metastatic subpopulations, while the expression of carcinoembryonic antigen (CEA), caspase-5, Fas ligand, Prk/FNK, cyclin E, cyclin B1, Ki-67, proliferating cell nuclear antigen (PCNA), Smad4, macrophage proinflammatory human chemokine-3 alpha (MIP-3 alpha)/LARC, Met and CD44 were downregulated. Data from the literature suggest that the altered expression of MMP-2, PAI-1, IL-1 alpha, CEA, caspase-5, Fas ligand, Prk/FNK and Smad4 promotes the highly metastatic phenotype. The differential expression of these genes was confirmed by Northern blot analysis, standard reverse transcription-polymerase chain reaction (RT-PCR) and real-time quantitative RT-PCR. This analysis in subpopulations of a lung cancer cell line indicated that the highly metastatic potential of lung cancer may be induced not by an alteration in the expression of a single gene, but by the accumulation of alterations in the expression of several genes involved in extracellular matrix (ECM) adhesion disruption, ECM degradation, escape from apoptosis, and resistance to transforming growth factor-beta(1) (TGF-beta(1)). Strategies for inhibiting metastasis of pulmonary adenocarcinoma should be designed accordingly.

Adenocarcinoma↗
PubMed2001

Hepatic graft-versus-host disease presenting as an acute hepatitis after allogeneic peripheral blood stem cell transplantation.

Hepatic graft-versus-host disease (GVHD) generally presents as cholestatic jaundice, and increased serum alkaline phosphatase (ALP) is followed by hyperbilirubinemia and clinical jaundice. Currently accepted standards for evaluating the clinical severity of GVHD are based not on serum aminotransferase levels but on the serum bilirubin level. We describe a 17-year-old Japanese female who had increased aminotransferases without cholestasis on day 23 after allogeneic peripheral blood stem cell transplantation (allo-PBSCT). Liver biopsy revealed lymphocytic infiltration of the portal tracts and pericentral necrosis of the lobuli. The limiting plates were not clearly defined due to cellular infiltrates. There was periductal lymphocytic infiltration and vacuolization of the biliary epithelial cells with exocytosis, compatible with GVHD of cholangiohepatitic type. These findings indicate that acute hepatic GVHD may present as acute hepatitis and this should be included in the differential diagnosis for patients with increased aminotransferases after allogeneic stem cell transplantation.

Acute Disease↗
PubMed2001

Synergistic effects of pegylated recombinant human megakaryocyte growth and development factor and granulocyte colony-stimulating factor on mobilization of hematopoietic progenitor and stem cells with long-term repopulating ability into peripheral blood in mice.

We investigated the effects of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on peripheral blood progenitor cell (PBPC) mobilization and the combined effect of PEG-rHuMGDF plus recombinant human granulocyte colony-stimulating factor (rhG-CSF) in C57BL/6 mice. Treatment of mice with PEG-rHuMGDF increased the numbers of day 8 and day 12 spleen colony-forming units (CFU-S), and pre-CFU-S in the PB. Ten days administration of PEG-rHuMGDF could mobilize higher numbers of days 8 and day 12 CFU-S than 5 days administration. An optimal dose of PEG-rHuMGDF mobilized a higher number of committed progenitor cells (day 8 CFU-S) and a lower number of immature progenitor cells (pre-CFU-S) into PB than rhG-CSF. The combined administration of optimal or suboptimal doses of PEG-rHuMGDF and rhG-CSF induced synergistic effects on mobilization of CFU-S and pre-CFU-S into PB compared to either factor alone. Four months after sex-mismatched PBPC transplantation, long-term donor-derived engraftment was observed in all recipients that had been transplanted with PBPCs mobilized by rhG-CSF and/or PEG-rHuMGDF, as determined by Y-chromosome polymerase chain reaction (PCR) analysis. Our data suggest that cytokine-induced pathways for PBPC mobilization may be different between PEG-rHuMGDF and rhG-CSF and indicate that PEG-rHuMGDF alone or the combination with rhG-CSF may be useful in effective PBPC mobilization.

Animals↗
PubMed2001

Value of lymph node dissection during resection of intrahepatic cholangiocarcinoma.

BACKGROUND: Hepatectomy with extensive lymph node dissection is the standard operation for intrahepatic cholangiocarcinoma (IHCC). However, lymph node dissection may not always be effective at reducing tumour recurrence. METHODS: Forty-nine patients with IHCC who underwent hepatectomy were investigated to determine patterns of tumour recurrence and to estimate the value of lymph node dissection during resection. RESULTS: At hepatectomy most metastatic lymph nodes were identified at least to the level of group 2 lymph nodes. Among 23 patients who developed recurrence, 17 had liver metastases and the other six had recurrence at other sites, mainly in the peritoneum. Poorly differentiated histology was related to the development of liver metastases. No patient with the intraductal growth type of IHCC had tumour recurrence. Lymph node dissection did not appear to improve patient survival. Histological findings of lymph node metastases and intrahepatic metastases were independent indicators of poor prognosis. CONCLUSION: Lymph node metastases were seldom limited to the regional lymph nodes; most tumour recurrence occurred in the liver. Lymph node dissection did not appear to improve patient survival. Lymph node dissection alone is not likely to improve the prognosis without further control of liver metastases.

Bile Duct Neoplasms↗
PubMed2001

Prevention of murine acute graft-versus-host disease by staphylococcal enterotoxin B treatment.

Retroviral superantigens such as minor lymphocyte stimulating (Mls) antigen play an important role in the pathogenesis of acute graft-versus-host disease (GVHD). However, it remains unclear how exogenous bacterial superantigens modulate acute GVHD. In this study, we tested the effects of staphylococcal enterotoxin B (SEB) on the development of acute GVHD in a model involving the systemic transfer of parental C57Bl/6 spleen cells into BDF1 mice. SEB treatment suppressed the expansion of donor-derived T cells and blocked the decrease in the number of host cells. Impaired haematopoiesis was actually rescued by treatment with SEB. In SEB-treated mice, both spontaneous proliferation and IL-2 production in T cells were suppressed on day 2 after parental cell infusion. On day 21, the number of donor-derived CD4+ Vbeta8+ T cells markedly decreased in the spleen of SEB-treated mice. Donor-derived CD4+ T cells failed to proliferate in response to host alloantigens, and both donor- and host-derived T cells were unable to produce IL-2 in response to concanavalin A stimulation, suggesting that SEB treatment induced a general immunosuppressive state. Our results indicate that SEB treatment prevents the development of acute GVHD by leading to unresponsiveness of donor-derived T cells against host alloantigens in a Vbeta-restricted and unrestricted manner.

Acute Disease↗
PubMed2001

Evidence for a single nucleotide polymorphism in the KCNQ1 potassium channel that underlies susceptibility to life-threatening arrhythmias.

INTRODUCTION: Congenital long QT syndrome (LQTS) is a genetically heterogeneous arrhythmogenic disorder caused by mutations in at least five different genes encoding cardiac ion channels. It was suggested recently that common polymorphisms of LQTS-associated genes might modify arrhythmia susceptibility in potential gene carriers. METHODS AND RESULTS: We examined the known LQTS genes in 95 patients with definitive or suspected LQTS. Exon-specific polymerase chain reaction single-strand conformation polymorphism and direct sequence analyses identified six patients who carried only a single nucleotide polymorphism in KCNQ1 that is found in approximately 11% of the Japanese population. This 1727G>A substitution that changes the sense of its coding sequence from glycine to serine at position 643 (G643S) was mostly associated with a milder phenotype, often precipitated by hypokalemia and bradyarrhythmias. When heterologously examined by voltage-clamp experiments, the in vitro cellular phenotype caused by the single nucleotide polymorphism revealed that G643S-KCNQ1 forms functional homomultimeric channels, producing a significantly smaller current than that of the wild-type (WT) channels. Coexpression of WT-KCNQ1 and G643S-KCNQ1 with KCNE1 resulted in approximately 30% reduction in the slow delayed rectifier K+ current I(Ks) without much alteration in the kinetic properties except its deactivation process, suggesting that the G643S substitution had a weaker dominant-negative effect on the heteromultimeric channel complexes. CONCLUSION: We demonstrate that a common polymorphism in the KCNQ1 potassium channel could be a molecular basis for mild I(Ks) dysfunction that, in the presence of appropriate precipitating factors, might predispose potential gene carriers to life-threatening arrhythmias in a specific population.

Adult↗
PubMed2001

Anticancer molecular mechanism of 3'-ethynylcytidine (ECyd).

The antitumor ribonucleoside analogue 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine (ECyd), synthesized in 1995, has strong antitumor activity. In mouse mammary tumor FM3A cells, ECyd was rapidly phosphorylated to ECyd-triphosphate (ECTP) as the final product, strongly inhibiting RNA synthesis. The ultimate metabolite of ECyd, ECTP, is stable in cultured FM3A cells with a half-life of 21 hr; ECyd is on a "closed" metabolic pathway to ECTP. Deaminated ECyd derivatives were minor metabolites in the cells treated with Ecyd; therefore cytidine forms probably were not converted to uridine forms at the nucleoside or nucleotide stage. The characteristics of ECyd may be important for the antitumor activity. RNA polymerase in the nucleus was inhibited competitively by ECTP; the ki value was 21 nM. ECyd induced DNA and 28S ribosomal RNA fragnetations. The cleavage pattern of rRNA resembled in that mediated by RNase L. The results suggested that RNase L related mechanisms might be involved in the antitumor activity of ECyd.

Animals↗
PubMed2001

Germinated barley foodstuff exhibits different adsorption properties for hydrophilic versus hydrophobic bile acids.

BACKGROUND/AIMS: Germinated barley foodstuff (GBF), a type of dietary fiber, exhibits therapeutic effects in ulcerative colitis (UC) patients. However, the precise mechanisms responsible for these effects are still under investigation. On the other hand, it has been suggested that bile salts in the gut lumen play an important role in the integrity of the intestinal mucosa. The aim of the present study was to investigate the ability of GBF to adsorb bile salts in vitro. METHODS: The binding capacities of GBF, enzymatically digested GBF (GBF-fiber), and alpha-cellulose for unconjugated and conjugated bile salts were measured using Langmuir's method. The morphology of these fibers was observed by light and fluorescence microscopy. RESULTS: GBF adsorbed bile salts very strongly, especially hydrophobic bile salts. Even after enzymatic digestion, the GBF fiber still exhibited strong binding capacity, whereas alpha-cellulose exhibited very low binding capacity. Microscopically, GBF consists mainly of aleurone, a lattice-like cell wall with cytoplasm enclosed. After enzymatic digestion, the cytoplasm was also digested. CONCLUSION: GBF possesses a great capacity to adsorb bile salts. This may be part of the mechanism for the therapeutic effects of GBF in UC patients.

Adsorption↗
PubMed2001

Initial experience with nifekalant hydrochloride (MS-551), a novel class III antiarrhythmic agent, in patients with acute extensive infarction and severe ventricular dysfunction.

Nifekalant hydrocholoride, a novel class III antiarrhythmic agent, was used as the treatment in 4 patients with extensive anterior infarction and severe ventricular dysfunction. The malignant ventricular tachyarrhythmia was effectively suppressed at a relatively low dose, without compromising the hemodynamics, indicating that this potent K+ channel blocker has therapeutic potential for acute myocardial infarction.

Aged↗
PubMed2001

Hypertrophic cardiomyopathy with midventricular obstruction and apical aneurysm: a case report.

A 71-year-old woman had hypertrophic cardiomyopathy associated with midventricular obstruction and an apical aneurysm in the left ventricle. She had had abnormal electrocardiograms for more than 30 years and for the past year had been suffering from occasional attacks of dizziness and low systemic blood pressure. Holter 24-h electrocardiographic monitoring revealed ventricular paroxysmal contractions (676/day) with nonsustained ventricular tachycardia. Doppler echocardiography revealed paradoxical jet flow from the apical aneurysm to the left ventricular outflow during early diastole. Magnetic resonance imaging depicted midventricular hypertrophy and a dyskinetic thin apical wall, which were confirmed by angiography. Coronary angiograms showed no narrowing of the major extramural coronary arteries, but there was compression of aberrant coronary arteries apparently feeding the hypertrophic portion of the left ventricular wall. Stress thallium-201 myocardial imaging showed a persistent severe defect in the left ventricular apex. A hemodynamic study revealed low cardiac output and an intraventricular pressure gradient (approximately 90 mmHg) between the left ventricular apical high-pressure chamber and the subaortic low-pressure chamber. The present case represents a rare combination of hypertrophic cardiomyopathy, midventricular obstruction, and an apical aneurysm in an elderly woman. Myocardial ischemia may have played an important role in the genesis of the apical aneurysm.

Aged↗
PubMed2001

Reversible left ventricular systolic dysfunction--reversibility of coronary microvascular abnormality.

Reversible left ventricular wall motion abnormalities mimicking myocardial infarction have been reported in patients with a noncardiac illness. Their coronary angiograms do not demonstrate organic stenosis or epicardial coronary vasospasm. In this article, two cases of reversible left ventricular contraction abnormality are presented. Electrocardiography showed deep inverted T waves in precordial leads, and the echocardiography revealed diffuse akinesis of the apical region in the acute phase. Coronary angiography showed no significant stenosis or occlusion in either patient. Thallium scintigraphy showed no defect, while the metaiodobenzylguanidine scintigraphy demonstrated significant defects in the apex. The relative coronary flow reserve ratio, measured with an intracoronary Doppler flow wire, was significantly reduced in both patients. Myocardial contrast echocardiography revealed a reversible perfusion defect in the apex in the acute phase in case 2. Transiently impaired coronary microcirculation was thought to be involved in the pathogenesis of the reversible left ventricular dysfunction observed in these patients.

Aged↗
PubMed2001

Lamivudine and glycyrrhizin for treatment of chemotherapy-induced hepatitis B virus (HBV) hepatitis in a chronic HBV carrier with non-Hodgkin lymphoma.

We report a chronic hepatitis B virus (HBV) carrier with non-Hodgkin lymphoma (NHL) who developed HBV hepatitis following conventional dose chemotherapy and was successfully treated with lamivudine and glycyrrhizin. A 55 year-old male patient with primary testicular NHL (diffuse large B-cell type) relapsed. During the salvage chemotherapy, the patient showed elevated serum levels of transaminase and HBV-DNA due to HBV reactivation. Treatment with lamivudine, an antiviral nucleoside analog, was started at a dose of 100mg/day. Shortly after the treatment the HBV-DNA level was suppressed, and sustained elevation of transaminase levels were normalized after additional treatment with glycyrrhizin. This experience suggests that lamivudine combined with glycyrrhizin may be effective for controlling HBV replication and treating chemotherapy-induced HBV hepatitis in chronic HBV carriers with NHL.

Anti-HIV Agents↗