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Biomedical subjects

N Katayama

Publications and source records attributed to N Katayama.

At least 163 records · Page 9Linked to original sources
PubMed1998

Human parvovirus B19 capsid antigen in granulocytes in parvovirus-B19-induced pancytopenia after bone marrow transplantation.

A patient with refractory anemia with an excess of blasts in transformation developed pancytopenia and a concurrent interstitial pneumonia 110 days after allogeneic bone marrow transplantation. Bone marrow examination showed 0.4% giant proerythroblasts and 86.2% granulocytes, some of them large with a bizarre configuration and the others of normal size. Serum folate level was found low, 0.6 ng/ml. Immunocytochemistry with a B19-specific monoclonal antibody MAB8292 revealed B19 capsid antigen only in erythroblasts and large, bizarre granulocytes, but not in granulocytes of normal size. In situ hybridization of bone marrow cells using digoxigenin-labeled DNA probes detecting parvovirus B19 also demonstrated positive signals in 8.5% of marrow cells. Parvovirus B19 DNA was isolated from the serum and the bronchoalveolar lavage fluid of this patient by the polymerase chain reaction. These findings suggest that neutropenia may be caused by an involvement with parvovirus B19 though a deficiency of folic acid may have in part contributed to the genesis of neutropenia in the patient. The relevance of parvovirus B19 to the interstitial pneumonia remains unclear.

Adult↗
PubMed1998

Possible involvement of calcineurin in retinoic acid-induced inhibition of leukemic HL-60 cell proliferation.

Differentiation of leukemic HL-60 cells by all transretinoic acid (ATRA) resulted in a reduced rate of growth. Cyclosporin A and FK506, at concentrations that inhibited calcineurin activity, abrogated the ATRA-induced inhibition of HL-60 cell growth but these immunosuppressants had no effect on the ATRA-induced granulocytic differentiation. Treatment with 1 microM ATRA led to a progressive increase in calcineurin phosphatase activity of HL-60 cells; the increase in this activity appeared to parallel the functional change of HL-60 cells during granulocytic differentiation. Increase in calcineurin activity was concordant with the increased expressions of calcineurin A and calcineurin B subunit proteins. The FKBP12 expression increased during ATRA-induced differentiation and expression of cyclophilin A remained unchanged. We propose that the increased expression of calcineurin is involved in the ATRA-induced inhibition of HL-60 cell proliferation, as in the case with 1,25alpha-dihydroxy-vitamin D3.

Calcineurin↗
PubMed1998

Sympathetic nerve response to muscle during anteroposterior acceleration in humans.

This study aimed to elucidate the effects of linear acceleration on muscle sympathetic nerve activity (MSNA) in humans. Eight healthy young male volunteers were seated in a linear accelerator (sled) during the recording of their electrocardiogram, blood pressure with the Finapres, thoracic impedance and respiration curve. MSNA was recorded from the tibial nerve by microneurography. At a fixed distance of sled movements in an anteroposterior direction, eight modes of stimulation with peak accelerations at 0.05, 0.10, 0.15, and 0.20 G (gravity) in sinusoidal or step mode were applied to each subject. Each movement was repeated for 5 cycles. Both the total activity and the burst rate of MSNA decreased during acceleration, and the level of the decrease was proportional to the level of the acceleration, whereas the average heart rate, thoracic impedance and mean arterial pressure did not change significantly. These results suggests that moderate linear acceleration may suppress MSNA in humans.

Acceleration↗
PubMed1998

Elicitation of vestibular nystagmus by a step mode of horizontal linear acceleration.

Elicitation of lateral nystagmus to linear acceleration in the interaural axis of the head was examined in 35 healthy subjects who were seated upright in darkness within the capsule (sled) of an accelerator. The motion stimulus was a step-mode oscillation of 0.3 G and 0.5 G at a distance of 10 m, though an additional 0.1 G stimulus was given in 10 subjects. The nystagmus was already fully elicited at 0.3 G in 13 subjects. In 9 of the remainder, however, the occurrence was newly developed or further improved at 0.5 G. When 10 subjects among the full-elicitation group at 0.3 G were examined at 0.1 G, only one subject still maintained high susceptibility. G-direction-dependent asymmetry was frequently observed in the nystagmus elicitation. Such directional preponderance was distinct at 0.3 G, but lessened at 0.5 G, when the subjects were examined whose nystagmus elicitation was very frequent. The results indicate that a greater G-load is more efficient for nystagmus elicitation, but may eliminate further chances to identify the response properties.

Acceleration↗
PubMed1997

The Co2+ Adsorption Properties of Al2O3, Fe2O3, Fe3O4, TiO2, and MnO2 Evaluated by Modeling with the Frumkin Isotherm

Adsorption of Co(II) ions on metal oxides is related to radioactive 60Co(II) (de)contamination of nuclear power plants, Co(II) ion retention in soils as a plant nutrient, concentration of Co(II) in deep-sea manganese nodules, and other applications. Here, the amount of adsorbed Co(II) on metal oxides was measured as a function of the pH and concentration of Co(II) ions, and the adsorption properties of metal oxides were evaluated with a model that considers simultaneous (1:1) and (1:2) exchange reactions between Co2+ aqua ions and surface hydroxyl protons obeying the Frumkin isotherm. The possibility of participation of mono- and polynuclear Co(II) hydroxo complexes in the adsorption was examined, and it was suggested that these species play no role under the conditions here. From the model parameters, it was found that the Co2+ adsorption ability of metal oxides increases in the order Al2O3 < Fe2O3 < TiO2 < Fe3O4 < MnO2, showing a good correlation to the electronegativity Xi of the lattice metal ions of the oxides. The Co2+ adsorption was divided into two processes: (1) deprotonation of surface hydroxyl sites and (2) bonding of Co2+ to the deprotonated sites with a negative charge. With increasing Xi, process 1 increases possibly due to the decrease in the donor electron density responsible for covalent bonds with protons, while process 2 changes only slightly. It was suggested that process 2 is due to ionic bond formation ("electrostatic contact adsorption"), which is independent of the donor electron density, and the correlation of the overall process to Xi found here was ascribed to process 1 above. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed1997

Osteopetrosis and total hip arthroplasty. Report of two cases.

Two patients with osteopetrosis and osteoarthrosis of the hip underwent "hybrid" total hip replacement. There are technical difficulties in seating acetabular and femoral components on hard and brittle osteopetrotic bone with an obliterated marrow cavity. Although the surgical procedures are challenging, this form of arthroplasty is recommended for hip osteoarthrosis which is associated with osteopetrosis.

Adolescent↗
PubMed1997

Cellular characteristics of acute leukemia cells simultaneously expressing CD13/CD33, CD7 and CD19.

Of 832 acute leukemia patients, including 580 acute myeloblastic leukemia (AML), 197 pre-B acute lymphoblastic leukemia (ALL) and 55 pre-T ALL, 26 cases (3.1%) of CD13/CD33+CD7+CD19+ acute leukemia were found. A total of 20 patients were diagnosed as AML, two as pre-B ALL and four as pre-T ALL. Based on the relative intensity of expression of CD7 and CD19, CD13/CD33+CD7+CD19+ acute leukemia patients were subclassified into three categories. Type I (CD7 > CD19) included ten AML and four pre-T ALL, having cellular characteristics similar to CD7+ AML and CD13/CD33+CD7+ ALL. Type II (CD7 < CD19) consisted of four AML with t(8;21) and two pre-B ALL. Type III (CD7 = CD19) included six AML. CD13/CD33+CD7+CD19+ acute leukemia frequently expressed stem cell associated molecules, such as CD34 (88.5%), HLA-DR (96.2%) and mRNA for MDR1 (72.2%), GATA-2 (87.5%) and SCL (25.0%). Simultaneous expression of cytoplasmic CD3 and myeloperoxidase in some leukemia cells implies that CD13/CD33+CD7+CD19+ acute leukemia cells have the potential to differentiate into various lineages. These data suggest that a small population of acute leukemia patients with distinct phenotype, CD13/CD33+CD7+CD19+ acute leukemia, may originate from hematopoietic stem cells.

Antigens, CD↗
PubMed1997

Increased serum levels of thrombopoietin in patients with thrombotic thrombocytopenic purpura, idiopathic thrombocytopenic purpura, or disseminated intravascular coagulation.

The serum levels of thrombopoietin (TPO) were measured in 16 patients with thrombotic thrombocytopenic purpura (TTP), 12 with hemolytic uremic syndrome (HUS), 10 with aplastic anemia (AA), 10 with disseminated intravascular coagulation (DIC), and 71 with idiopathic thrombocytopenic purpura (ITP). The serum TPO levels were measured with a sensitive sandwich enzyme-linked immunosorbent assay. The serum TPO level in the ITP group (1.68 +/- 0.85 fmol/ml) were not significantly increased compared with those of the normal subjects. The TPO levels in the TTP (2.77 +/- 1.38 fmol/ml) and HUS groups (5.77 +/- 4.41 fmol/ml) were higher than those of the normal subjects. The patients with AA (12.7 +/- 8.0 fmol/ml) and those with DIC (13.3 +/- 5.7 mol/ml) had significantly higher serum TPO levels than did the normal subjects and ITP patients. The TPO levels were well correlated with the platelet counts in the TTP patients, and were negatively correlated with the platelet counts in the ITP patients. These results suggest that the serum TPO levels in some thrombocytopenic diseases are regulated not only by the platelet count and the megakaryocyte mass, but also by other factors.

Adult↗
PubMed1997

Role for C-MPL and its ligand thrombopoietin in early hematopoiesis.

Proto-oncogene c-mpl is structurally homologous with the hematopoietic growth factor receptor superfamily. The ligand for c-mpl was purified and its gene cloned. Extensive functional studies revealed that the ligand for c-mpl plays a crucial role in megakaryocytopoiesis and platelet production, hence, this ligand proved to be the long-sought hematopoietin, thrombopoietin (TPO). We briefly review here the role for TPO in early hematopoiesis, based on our in vitro data obtained using a serum-free culture system. TPO in combination with the ligand for c-kit (SF) or interleukin-3 (IL-3) but not TPO alone supported the growth of murine primitive hematopoietic progenitors. Studies on lineage expression indicated that the progenitors supported by TPO plus SF or TPO plus IL-3 are multipotential. Delayed addition experiments demonstrated that TPO has the potential to effectively support the survival of primitive hematopoietic progenitors. TPO also hastened IL-3-dependent growth of progenitors by shortening the time required for cell-cycling. While size of the colonies did not differ between colonies supported by IL-3 alone and those supported by IL-3 plus TPO, the incidence of megakaryocyte-containing colonies in cultures supported by IL-3 plus TPO was higher than that in cultures supported by IL-3 alone. Taken together, TPO as a single factor can support the survival of hematopoietic progenitors and TPO synergizes with SF or IL-3 to be active on early multipotential hematopoietic progenitors. These findings suggest that the function of TPO initially thought to be restricted to the megakaryocytic lineage proved to be greater in hematopoiesis. Reports from other laboratories regarding the involvement of TPO in early hematopoiesis are also discussed.

Animals↗
PubMed1997

Stage-specific cell-cycling of hematopoietic progenitor cells.

We studied the growth of hematopoietic progenitors at different progressive stages of differentiation and focused especially on changes in cell-cycling. Hematopoietic progenitors from 5-fluorouracil (5-FU)-treated mice were separated into three groups on the basis of differentiation, Stages I, II, and III, and have studied their cell-cycling. Primary marrow cells collected from 5-FU-treated mice were categorized as Stage I progenitors. Stages II and III progenitors are early and late progenies of Stage I progenitors, respectively. The rate of growth of hematopoietic progenitors supported by interleukin-3 (IL-3) and steel factor (SF) was estimated by sequential analysis of colony formation and studying replating efficiency of individual colonies. The time required for hematopoietic progenitors to go through the cell-cycle shortened as their stage of differentiation progressed. Similar results were obtained with other growth factor combinations. The analysis of DNA content of cells suggests that shortening of cell-cycling is mainly due to a decrease in the time of G1 phase of the cell-cycle. Our results demonstrate that in early hematopoiesis, the cell-cycling of hematopoietic progenitors accelerates as they differentiate.

Animals↗
PubMed1996

Accelerated cell-cycling of hematopoietic progenitors by the flt3 ligand that is modulated by transforming growth factor-beta.

Although hematopoietic growth factors have been extensively studied as to their roles in recruitment of hematopoietic progenitors from quiescence state to cell division state, little is known of their effects on cell-cycling of progenitors that have already transited from quiescence into active cell-cycling. We examined the effects of the flt3 ligand (FL) on cell-cycling of hematopoietic progenitors in serum-free culture. Results from our serial observations of colony formation and replating experiments suggest that FL enhances the rate of growth of interleukin-3 (IL-3)-dependent colonies by shortening the time for each progenitor in the colonies to divide. Cell-cycle analysis showed that shortening of cell-cycle time induced by FL is mainly because of alteration in the G1 phase that hematopoietic progenitors go through. We next investigated the role of transforming growth factor-beta (TGF-beta) in cell-cycling of progenitors, using TGF-beta protein and TGF-beta antisense oligonucleotides, because mRNA of TGF-beta was detected by reverse transcriptase polymerase reaction in blast cells that we used as a source of progenitors. TGF-beta lengthened the time required for IL-3-dependent progenitors to become two daughter cells, whereas the effects of TGF-beta antisense oligonucleotides were opposite to those of TGF-beta. The addition of TGF-beta neutralizing monoclonal antibodies to the cultures resulted in effects similar to those seen with TGF-beta antisense oligonucleotides. DNA studies indicated that both TBF-beta and TGF-beta antisense oligonucleotides change the length of G1 phase of the cell-cycle. TGF-beta abrogated the effects of FL on the growth rate of hematopoietic progenitors, whereas the combination of FL with TGF-beta antisense oligonucleotides exerted additive effects. These data show that FL has the potential to accelerate cell-cycling of hematopoietic progenitors, which is susceptible to the modulation by TGF-beta.

Animals↗
PubMed1996

Morgagni hernia diagnosed by MRI.

We herein present a patient with Morgagni hernia which was diagnosed by magnetic resonance imaging (MRI). The patient had a progressively enlarging mass in the right cardiophrenic angle on chest roentgenogram. On computed tomography (CT) scans, the mass was revealed to have fat density and therefore was suspected to be either a lipoma or liposarcoma. MRI clearly demonstrated that the mass shadow was composed of omental fat herniating into the right thorax through the diaphragmatic hiatus. MRI is thus considered to be a useful noninvasive modality for the evaluation of lower anterior mediastinal masses demonstrating fat density on CT.

Adipose Tissue↗
PubMed1996

A possible change in doubling time of haemopoietic progenitor cells with stem cell development.

We separated haemopoietic progenitors derived from marrow cells of 5-fluorouracil (5-FU)-treated mice into three groups, based on the stages of stem cell development and studied doubling time, using a serum-free clonal culture system. Stage I progenitors were those present in primary marrow cells from 5-FU-treated mice. Stages II and III progenitors were early and late progenies in culture of stage I progenitors respectively. The morphological analysis of colonies derived from stage I, II and III progenitors demonstrated an association of progression of stages with loss of multipotentiality. The doubling time of haemopoietic progenitors was estimated by sequential analysis of colony formation and studies of growth fraction. The time required for haemopoietic progenitors to double shortened as their stage of development progressed. Alteration in one doubling time of haemopoietic progenitors at progressive stages of stem cell development was seen in cultures supported by various combinations of growth factors, including interleukin-3 (IL-3), IL-11. and steel factor (SF), Cell-cycle analysis suggested that reduction of the doubling time of haemopoietic progenitors is probably due to a decrease in the time spent in the G1 phase of the cell cycle. Our results suggest that in early haemopoiesis the doubling time of haemopoietic progenitors may change with stem cell development.

Animals↗