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Biomedical subjects

K Ando

Publications and source records attributed to K Ando.

At least 127 records · Page 7Linked to original sources
PubMed2000

Comparison of the effects of add-back therapy with various natural oestrogens on bone metabolism in rats administered a long-acting gonadotrophin-releasing hormone agonist.

The hypoestrogenic state induced by gonadotrophin-releasing hormone agonist (GnRHa) has been shown to be effective in the treatment of oestrogen-dependent disorders but to induce bone loss. Adding back low doses of oestrogen in GnRHa therapy has been proposed to prevent bone loss. The purpose of this study is to assess the efficacy of add-back therapy with different natural oestrogens such as oestrone (OE(1)), oestradiol (OE(2)) and oestriol (OE(3)). Three-month-old female rats (250 g) were subcutaneously administered microcapsules of leuprorelin acetate in doses of 1 mg/kg of body weight every 4 weeks. GnRHa therapy lasted 16 weeks, and pellets of OE(1), OE(2) or OE(3) (0.5 mg/pellet, 60 day release), as an add-back agent, were implanted at 8 weeks of treatment. At the end of treatment, GnRHa alone decreased bone mineral density of the femur and lumbar vertebrae, and increased serum levels of bone metabolic markers such as alkaline phosphatase and osteocalcin levels. As for cancellous bone histomorphometry, GnRHa decreased bone volume while it increased osteoid volume, osteoid surface, eroded surface, mineral apposition rate and bone formation rate. All the oestrogens tested prevented these changes caused by GnRHa therapy. GnRHa induced a significant increase in body weight and a marked reduction in uterine weight, which was not observed in OE(1) or OE(2) add-back group. Body weight and uterine weight of the OE(3) add-back group were the same as those of the GnRHa group. These findings indicate that GnRHa induces high turnover bone loss which can be prevented by concomitant administration of natural oestrogens such as OE(1), OE(2) and OE(3) to the same extent. In addition, OE(3) is unique in that it is much less effective than OE(1) and OE(2) in blocking body weight gain and in promoting growth of uterine tissues. Because of its tissue-selective actions, OE(3) could be considered as one of the most appropriate oestrogens used for GnRHa add-back therapy.

Alkaline Phosphatase↗
PubMed2000

IgA-lambda/IgG-kappa biclonal myeloma in which two clones proliferated in individual sites.

A 72-year-old man was admitted to our hospital because of lumbago and numbness of legs. Tumor invasion at the fourth lumbar vertebra was revealed. Immunohistochemistry using specific antibodies against each heavy and light chain of immunoglobulin revealed that the myeloma cells in bone marrow were all IgA-lambda type whereas they were all positive for IgG-kappa type in a tumor of the fourth lumbar vertebra. These data indicate that the patient had IgG-kappa/IgA-lambda biclonal myeloma. Different phenotypes of M-proteins and distinct proliferating sites for two clones suggest that they may have resulted from two independent transforming events.

Aged↗
PubMed2000

Telomere dynamics and genetic instability in disease progression of chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is characterized by a Philadelphia (Ph) translocation creating a novel BCR-ABL oncoprotein, and CML patients have a chronic phase for several years followed by an intractable blast cell proliferation, called blast transformation. In the blast phase, more than 60% of patients show additional cytogenetic changes, e. g., double Ph, +8, i(17q). In this review, we would like to address genetic changes, including genome instability, cytogenetic changes, and telomere dynamics that relate to karyotypic instability. In the chronic phase, approximately 60% of CML patients show reduced telomere length without highly elevated telomerase activity or microsatellite alterations, indicating that telomere reduction may be linked to cell replication. Therefore, the Ph translocation might be a first event to immortalize cell proliferation. In the blast phase, 50% of CML patients have high levels of elevated telomerase activity and the same number of patients had microsatellite changes. Of note is that most patients with telomerase up-regulation in the blast phase had additional cytogenetic changes and >60% of them showed microsatellite changes at least at one locus. In contrast, most patients without telomerase activity did not show microsatellite changes. These findings may indicate that telomerase up-regulation in the blast phase of CML patients is closely associated with microsatellite changes (representative of genome instability), while blast cells in the remaining patients (30%) maintain their proliferative capability without microsatellite changes and telomerase up-regulation. This further suggests that there is also an unknown mechanism for genome stability without the process of telomerase up-regulation in some patients with CML in blast crisis.

Cell Transformation, Neoplastic↗
PubMed2000

[Regional differences of in vivo proton MR spectroscopy in developing human brain].

The purpose of this study was to clarify regional differences in proton MR spectroscopy (1H-MRS) in the developing human brain. Proton MR spectra were obtained from 24 infants aged 0 to 24 months old. Proton MR spectroscopy was performed on a 1.5 Tesla clinical MR unit using a 3D-chemical shift imaging sequence (3D-CSI). MR spectra obtained from voxels in frontal white matter and those in parietal white matter were compared. The NAA/Cho ratios of the frontal region were lower than those of the parietal region at birth but increased rapidly during the first six months of life. The rate of increase was reduced in the second year of life. In contrast, NAA/Cho ratios in paracentral areas were already high at birth but increased slowly through the first two years of life. Cho/Cr ratios of the frontal region were stable during the first year of life and started to decrease in the second year of life. In the parietal region, Cho/Cr ratios were decreased throughout infancy. Regional differences in 1H-MRS spectra were apparent during infancy, and these differences were suggested to reflect regional differences in the maturation of the developing human brain.

Adult↗
PubMed2000

[Identification of a free non-tryptophan fluorophore in water-soluble fraction of human brunescent cataractous lens nucleus].

PURPOSE: We previously reported that a unique free fluorophore (Fl-Glc), presumably a beta-glucoside, is particularly abundant in human brunescent cataractous lens nuclei. Our preliminary experiments indicated that incubation of low-molecular weight (MW) fraction of non-brunescent lens nuclei causes an increase in a particular fluorophore (Fl-X). This study was undertaken to compare the Fl-Glc with the Fl-X and subsequently to identify the Fl-X. METHODS: Experiment 1. The purified Fl-X and its beta-glucosidase digest (aglycon) were compared with the Fl-Glc and its aglycon, respectively, by high-performance liquid chromatography (HPLC). Experiment 2. i) The Fl-X and its aglycon were analysed by liquid chromatography/mass spectrometry (LC/MS). ii) Authentic xanthurenic acid was analysed by HPLC and LC/MS. RESULTS: Experiment 1. The retention times of the Fl-X and the Fl-Glc exactly coincided. The fluorescence peaks of both disappeared after beta-glucosidase treatment. Experiment 2. i) LC/MS results suggested that the MWs of the Fl-X and its aglycon were 367 and 205, respectively. ii) HPLC and LC/MS results for xanthurenic acid (MW = 205) were exactly the same as those for the aglycon of the Fl-X. CONCLUSIONS: The Fl-Glc and the Fl-X are identical, and the Fl-X (= Fl-Glc) is a glucoside of xanthurenic acid.

Aged↗
PubMed2000

[Diffuse large B-cell lymphoma showing CNS invasion by CD30-positive multinuclear giant cells mimicking the clinical features of progressive multifocal leukoencephalopathy].

We report a 55-year-old woman with diffuse large B-cell lymphoma showing central nervous system (CNS) infiltration by CD30-positive lymphoma cells. The patient was admitted with pleural effusion, ascites and a large mass in the abdominal cavity. Southern blot analysis of DNA extracted from the ascites revealed IgJH rearrangement, and therefore she was initially diagnosed as B-cell neoplasia. She received combined chemotherapy (DICE and CHOP regimens), and achieved a transient clinical response. Three months later, she developed various neurological abnormalities, and brain magnetic resonance imaging revealed diffuse infiltration of the cerebral white matter. We considered the possibility of CNS involvement by the lymphoma or progressive multifocal leukoencephalopathy (PML), and began a course of anti-virus therapy and radiation therapy. Because multiple lumbar punctures demonstrated large multinuclear lymphoma cells in the cerebrospinal fluid, a diagnosis of metastatic CNS lymphoma was made. Immunohistochemistry revealed that these lymphoma cells were reactive with anti-CD30 antibody. Although the radiation therapy was temporarily effective against the CNS involvement, the patient died of systemic invasion of the lymphoma cells. The final diagnosis was diffuse large B-cell lymphoma on the basis of pathologic findings, immunohistochemistry, and Southern blot analysis using a mesenteric lymph node obtained at autopsy. Cytospin preparations and immunohistochemistry of specimens obtained from frequent lumbar punctures were useful for differentiating CNS lymphoma from PML.

Brain Neoplasms↗
PubMed2000

[Rapidly progressive fibrosis and increased CD68-positive cells in the bone marrow at the terminal stage of adult T-cell leukemia accompanied by polycythemia vera].

We report a case of adult T-cell leukemia (ATL) accompanied by polycythemia vera (PV) in which rapid development of myelofibrosis and clinical features of hemophagocytic syndrome (HPS) were observed at the terminal stage. The patient, a 53-year-old man who was born in Oita Prefecture, Japan, was diagnosed as having PV in 1996. He had undergone venesection but had not received any chemotherapy. In June 1997, he showed systemic lymphadenopathy with positivity for serum HTLV-1 antibody (x 10,240). Pathological findings and Southern blotting analysis for detection of monoclonal integration of HTLV-1 provirus DNA in a lymph node biopsy sample revealed that he also had acute-type ATL. Although several courses of chemotherapy were transiently effective, high fever, pancytopenia, increased serum LDH, hypoproteinemia and hyperferritinemia appeared, all of which were compatible with the clinical features of HPS. In addition, cytomegalovirus infection became evident. He died of multiple organ failure with rapid progression of myelofibrosis in May 1998. Detection of both increased CD68-positive histiocytes by immunohistochemistry and iron-stained phagocytic cells in marrow biopsy specimens appeared to be helpful for diagnosis of HPS in this patient, whose marrow showed myelofibrosis with hypocellularity.

Antigens, CD↗
PubMed1999

Ex vivo generation of CD34(+) cells from CD34(-) hematopoietic cells.

The human Lin(-)CD34(-) cell population contains a newly defined class of hematopoietic stem cells that reconstitute hematopoiesis in xenogeneic transplantation systems. We therefore developed a culture condition in which these cells were maintained and then acquired CD34 expression and the ability to produce colony-forming cells (CFC) and SCID-repopulating cells (SRCs). A murine bone marrow stromal cell line, HESS-5, supports the survival and proliferation of Lin(-)CD34(-) cells in the presence of fetal calf serum and human cytokines thrombopoietin, Flk-2/Flt-3 ligand, stem cell factor, granulocyte colony-stimulating factor, interleukin-3, and interleukin-6. Although Lin(-)CD34(-) cells do not initially form any hematopoietic colonies in methylcellulose, they do acquire the colony-forming ability during 7 days of culture, which coincides with their conversion to a CD34(+) phenotype. From 2.2% to 12.1% of the cells became positive for CD34 after culture. The long-term multilineage repopulating ability of these cultured cells was also confirmed by transplantation into irradiated NOD/SCID mice. These results represent the first in vitro demonstration of the precursor of CD34(+) cells in the human CD34(-) cell population. Furthermore, the in vitro system we reported here is expected to open the way to the precise characterization and ex vivo manipulation of Lin(-)CD34(-) hematopoietic stem cells.

Animals↗
PubMed1999

12-O-tetradecanoylphorbol-13-acetate-induced apoptosis is mediated by tumor necrosis factor alpha in human monocytic U937 cells.

12-O-tetradecanoylphorbol-13-acetate (TPA), a phorbol ester that is known as a tumor promoter, induces differentiation of myeloid cells and suppresses their proliferation. We studied the regulation of apoptosis by TPA in human monocytic cell line U937 cells that lack p53. Untreated U937 cells constitutively underwent apoptosis, and TPA enhanced apoptosis in these cells. Further studies showed that TPA increased production of tumor necrosis factor-alpha (TNFalpha) in U937 cells, and exogenously added TNFalpha induced apoptosis. Moreover, the induction of apoptosis by TPA was blocked by anti-TNFalpha antibody. Similar results were obtained in the myeloblastic cell line KY821 cells. We also found that the induction of apoptosis by TPA was increased in cells overexpressed with TNF receptor 1 but not in control cells. Furthermore, TPA failed to induce the production of TNFalpha and apoptosis in cells with either their protein kinase C or mitogen-activated protein kinase pathway blocked. Our results indicate that TPA induces apoptosis, at least in part, through a pathway that requires endogenous production of TNFalpha in U937 cells. Our data also suggest that the induction of apoptosis by TPA occurs through activation of protein kinase C and mitogen-activated protein kinase and TNFalpha is an autocrine-stimulating factor for the induction of apoptosis in these cells.

Apoptosis↗
PubMed1999

Role of phosphorylation of Alzheimer's amyloid precursor protein during neuronal differentiation.

Alzheimer's amyloid precursor protein (APP), the precursor of beta-amyloid (Abeta), is an integral membrane protein with a receptor-like structure. We recently demonstrated that the mature APP (mAPP; N- and O-glycosylated form) is phosphorylated at Thr668 (numbering for APP695 isoform), specifically in neurons. Phosphorylation of mAPP appears to occur during, and after, neuronal differentiation. Here we report that the phosphorylation of mAPP begins 48-72 hr after treatment of PC12 cells with NGF and that this correlates with the timing of neurite outgrowth. The phosphorylated form of APP is distributed in neurites and mostly in the growth cones of differentiating PC12 cells. PC12 cells stably expressing APP with Thr668Glu substitution showed remarkably reduced neurite extension after treatment with NGF. These observations suggest that the phosphorylated form of APP may play an important role in neurite outgrowth of differentiating neurons.

Alzheimer Disease↗
PubMed1999

Phosphorylation of the cytoplasmic domain of Alzheimer's beta-amyloid precursor protein at Ser655 by a novel protein kinase.

The cytoplasmic domain of Alzheimer's beta-amyloid precursor protein (APP) can be phosphorylated at Thr654, Ser655, and Thr668 (APP695 isoform numbering). Previous studies demonstrated that Ser655 of APP was phosphorylated by protein kinase C (PKC) and calmodulin-dependent protein kinase II (CaMKII) in vitro and by unidentified protein kinase(s) in vivo. We report here the characterization of a novel protein kinase (designated APP kinase I) which phosphorylates Ser655 of APP. APP kinase I was partially purified over 7,000-fold from rat brain and identified as a approximately 43 kDa protein that is distinct from a number of known protein kinases, including PKC and extracellular signal-regulated kinases (ERKs). The identification of a novel protein kinase that phosphorylates Ser655 will hopefully contribute to our understanding of the metabolism and/or function of APP in the pathogenesis of Alzheimer's disease (AD).

Alzheimer Disease↗
PubMed1999

Membrane proteins of human erythrocytes are modified by advanced glycation end products during aging in the circulation.

Recent immunological studies demonstrated that proteins in vivo in several diseases are subjected to post-translational modification by advanced glycation end products (AGEs), suggesting a potential role of AGEs in aging and age-enhanced disease processes such as diabetic complications, atherosclerosis and Alzheimer's disease. Nvarepsilon-(Carboxymethyl)lysine (CML) is one of the major AGE-structures demonstrated in vivo so far. In the present study, membrane proteins from young erythrocyte population were compared with those from senescent erythrocytes separated from the same individual in their CML-contents using a monoclonal antibody for CML (6D12). SDS-polyacrylamide gel electrophoresis and subsequent Western blot showed that 6D12 bound to the band 1, 2, 3, 4.2, 5, 6 and 7 proteins from senescent erythrocytes, but not to those from young erythrocytes. Furthermore, quantitative estimation of the reactivity of 6D12 to these erythrocyte membranes by ELISA showed that the reactivity of 6D12 to senescent erythrocyte membranes was 3- to 6-fold higher than that of young erythrocyte membranes. These results indicate that membrane proteins of circulating erythrocytes undergo CML-modification, and the modified proteins accumulated in an age-dependent manner during the life span of erythrocytes.

Aging↗