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N Tatsumi

Publications and source records attributed to N Tatsumi.

At least 19 recordsLinked to original sources
PubMed1995

Constitutive expression of the thrombopoietin gene in a human hepatoma cell line.

The gene of thrombopoietin (TPO) has been cloned and identified to be identical to gene of the c-mpl ligand. It is known that the mRNA of TPO is expressed in liver and kidney. However, it is not clarified which cells in the liver produce TPO. Using a human hepatoma cell line, HepG2, we demonstrated that the TPO mRNA was expressed by liver parenchymal cells without any stimulation. To clarify the regulation of the expression of the TPO mRNA in HepG2 cells by cytokines, we assessed the effects of 5 cytokines, transforming growth factor-beta 1, activin A, platelet-derived growth factor, hepatocyte growth factor, and interleukin-6. These cytokines have no significant regulative effect on the expression of the TPO mRNA in HepG2 cells. Our results suggest that liver parenchymal cells may be the TPO producing cells and also suggest that some hepatoma cells may produce TPO constitutively.

Base Sequence↗
PubMed1995

Down-modulation of c-kit mRNA and protein expression by erythroid differentiation factor/activin A.

We examined the effects of erythroid differentiation factor (EDF)/activin A on the expression of c-kit mRNA and protein in murine erythroleukemia (MEL) cells. EDF/activin A induced MEL cells to benzidine positive cells. Northern blot analysis showed that the c-kit mRNA expression was reduced synchronously with increase of beta-globin and uroporphyrinogen decarboxylase gene expression during EDF/activin A induced erythroid differentiation. Scatchard analysis indicated that the cell surface receptor number was reduced without change of affinity during differentiation. Our results suggest that EDF/activin A may act as a natural regulator of erythropoiesis with modulation of c-kit gene expression.

Activins↗
PubMed1995

Urinary sediment analyzed by flow cytometry.

A flow cytometer for the automated analysis of urinary sediment was designed, and its performance was examined by the evaluation of 821 specimens. Auramine O, a dye for DNA and RNA, was used for the staining of the sediment. Urine (5 ml or more) was processed by the instrument for sediment analysis. Conventional microscopic analysis was done for comparison. The RBC count, the WBC count, and the number of bacterial cells, epithelial cells, and casts found by the flow cytometer and by microscopy were compared. Correlation was high for all these results. The overall sensitivity, specificity, and efficiency (accuracy) in the items analyzed were 84.7%, 57.8%, and 67.2%, respectively. One hundred specimens could be analyzed by the instrument per hour. The instrument seemed useful for screening for urinary tract disorders to identify specimens that should be analyzed microscopically in routine laboratories.

Adolescent↗
PubMed1995

[Present and future of classification for white cells and leukemic cells in the routine clinical laboratory].

Renovation of laboratory medicine has been greatly advanced in the past decade. White cell differentiation has been done with the automated blood cell counter with high reliability with the combination of flow cytometry. Specific monoclonal antibodies have made FAB classification more precise, while the traditional cell classification still gives some extent of uncertainty for the decision of cell typing. High resolution chromosome analysis and DNA analysis enable one to define genetical leukemia types and patients' prognosis. Clinically the hematological data reported from the routine laboratory are regarded as very reliable, but an interpretation should be made carefully to select the patient treatment and prediction of prognosis. Here, four speakers were selected to show the present problems and some resolution for identification of white cells and leukemia cells. The importance of standardization work was also discussed for identification of white cells and leukemia cells examined by the traditional Romanovsky stain, automated blood cell counter, flow cytometric method, and chromosomal and DNA analytic methods. We concluded that all those methods should be standardized and interpretation would be harmonized to give common answers for clinical decisions.

Chromosome Mapping↗
PubMed1995

[Further evolution and leukocyte differential using an automated blood cell counter].

In the leukocyte differential, morphological differential has been usually performed with chromatoaffinity of blood cells, but physical differential is recently performed with biophysicochemical characteristics of blood cells using an automated blood cell counter. The trend of the leukocyte differential has changed to physical differential (automated count method) from morphological differential (eye count method). In the automated count method, leukocytes are differentiated into neutrophils, lymphocytes, monocytes, eosinophils and basophils according to the predetermined region of each leukocyte population on the cytogram using an automated blood cell counter. An automated count method is very useful for the screening test in the laboratory because of its high precision and accuracy for the normal samples. However, it is not easy to identify abnormal cells such as leukemia cells by an automated count method. Therefore, an automated count method dealing with various suspect flags generated using an automated blood cell counter must be used for such abnormal samples. In case of absolutely few leukemia cells in the peripheral blood during complete remission, the automated count method can not detect a leukemia cell and no suspect WBC flags are recognized by the automated blood cell counter. Development of an automated blood cell counter with a higher efficiency than now and a standard automated count method is awaited in the clinical laboratory.

Automation↗
PubMed1995

[A sensitivity of CRP determination of cord blood and neonatal serum for neonatal infection].

CRP was determined for 110 cord bloods and peripheral blood of 36 newborns collected within 72 hours after delivery for the early diagnosis of newborn infection. The determination of CRP was done by a counting immunoassay method using PAMIA-30(Sysmex, Kobe, Japan). Sample volume needed was small and the time for determination was short. Within-run and between-run precisions were satisfactory, with CV values being approximately 6%. The CRP of healthy newborns was lower than that of cord blood, and the mean value was 33.4 +/- 4.2 ng/ml and the value was not significantly different from that obtained from the newborn babies with turbid amnionic fluid or early rupture of a sac. The CRP gradually increased after delivery had a peak at 24 to 48 hours after delivery. This tendency was observed both in healthy and infected newborns. The data were divided into 6 groups depending on the time collected after delivery (6, 12, 24, 48, and 72 hours). The CRP of blood from infected newborns tended to have higher CRP than that of healthy newborns in each group. Increased amount of CRP (ng/ml/hrs) was calculated as ((CRP of peripheral blood at time x)--(CRP of cord blood))/x, and this value was significantly higher (p < 0.05) in infected newborns than in healthy newborns 12hrs and more after delivery. Thus, CRP might be useful for monitoring the newborn infection.

Biomarkers↗
PubMed1994

Transplantation of allogeneic peripheral blood stem cells after myeloablative treatment of a patient in blastic crisis of chronic myelocytic leukemia.

A 48-year-old man in blastic crisis of chronic myelocytic leukemia received a transplant of allogeneic peripheral blood stem cells. The donor was his HLA-identical sister, who refused to donate bone marrow cells, but agreed to donate peripheral blood stem cells. The patient received standard transplant conditioning with cyclophosphamide (120 mg/kg) and busulfan (16 mg/kg). Peripheral blood stem cells were mobilized with granulocyte colony stimulating factor and collected by apheresis. After transplantation, the white blood cell count and the result of microscopic analysis of the bone marrow became normal, and the leukocyte karyotype became 46XX. DNA fingerprinting showed complete chimerism. Graft-versus-host disease was suppressed with cyclosporine and methyl-prednisolone. The patient died of recurrence of leukemia on day 102+.

Blast Crisis↗
PubMed1994

Treatment with cytosine arabinoside and granulocyte colony-stimulating factor in patients with myelodysplastic syndrome and its leukemic phase.

Twenty-one patients with myelodysplastic syndrome (MDS) or overt leukemia resulting from MDS were treated with recombinant human granulocyte colony-stimulating factor (rhG-CSF) and cytosine arabinoside (Ara-C). Ara-C was administered in a dose of 20 mg/m2 every 12 h for 5 days and after 2 days 125 micrograms of rhG-CSF was administered for 10 days. After recovery of the leukocyte count the therapy was repeated, doubling the dose of Ara-C serially when possible. Of 13 patients with MDS, four achieved complete remission (CR), two good response (GR), two minor response (MR), and five no response (NR). Of eight patients with overt leukemia from MDS, only one with hyperplastic bone marrow achieved a partial response (PR) and the remaining seven achieved NR. The efficacy of the combination of rhG-CSF and Ara-C in the treatment of MDS and its leukemic phase is discussed, including at which time rhG-CSF should be administered: before, after or concomitantly with Ara-C. Multicenter randomized studies are needed in the evaluation of this combination therapy.

Adult↗
PubMed1993

Flow cytometric detection of recombinant human granulocyte-colony stimulating factor binding to leukemic cells.

To examine binding of recombinant human granulocyte-colony stimulating factor to myeloid cells, the factor was labeled with fluorescein isothiocyanate, and incubated with blood specimens, which were then analyzed by flow cytometry. Neutrophils demonstrated an increased fluorescence, while lymphocytes were negative. These cell fractions were used as controls for cytometric binding assays of leukemic cells. Six patients with lymphocytic leukemia were negative in this assay. Ten of 15 patients with myelocytic leukemia were positive. All patients (n = 5) in myeloblastic crisis of chronic myelogenous leukemia were also positive. The flow cytometry results correlated well with the results of colony formation in response to granulocyte-colony stimulating factor. The results indicate that our method is useful in predicting the susceptibility of leukemic cells to recombinant growth factors.

Flow Cytometry↗
PubMed1993

Cell kinetic effects of granulocyte colony-stimulating factor on the sensitivity of nonlymphocytic leukemia cells to cytosine arabinoside.

We measured the percentage of proliferating cells in peripheral blood and bone marrow of patients with nonlymphocytic leukemia by flow cytometry and immunostaining with antibodies to proliferating cell nuclear antigen (PCNA) and Ki-67. We evaluated the effects of granulocyte colony-stimulating factor (G-CSF) on nonlymphocytic leukemia cells. The S phase cell ratio, PCNA positive cell ratio, and Ki-67 positive cell ratio were higher after culture with G-CSF than culture without G-CSF. The ratio of viable cells was lower after culture with G-CSF followed by cytosine arabinoside (Ara-C) than culture with Ara-C alone. The number of clonogenic leukemic cells in methylcellulose was also smaller after culture with G-CSF followed by Ara-C than Ara-C alone. Our results suggest that the administration of G-CSF before induction chemotherapy enhances the sensitivity of antitumor agents against leukemic cells.

Adolescent↗
PubMed1993

[CSF in laboratory medicine].

The effect of granulocyte-colony stimulating factor (G-CSF) or macrophage-colony stimulating factor (M-CSF) on patients with malignant lymphoma was analyzed. G-CSF was administered for ten days after conventional chemotherapy causing an increase in the granulocyte and monocyte counts. The increase in these cells shortened the duration of a leukocyte count lower than 2000 or 3000/mm3. There were no detectable effects from G-CSF on other blood cells. M-CSF had no effect on any of these cells. Receptors of these cytokines on various types of leukemic cells were also analyzed by flow-cytometry using fluorescent isothianate-labelled G-CSF or M-CSF. With this simplified method, G-CSF receptors were detected on almost all of the myeloid acute leukemia cells, but not on the nonmyeloid leukemic cells. M-CSF receptors were also detected on all of the monocytic acute leukemic cells, but not on myelocytic or lymphocytic leukemic cells.

Acute Disease↗
PubMed1993

Flow cytometric analysis of G-CSF receptors on normal white cells and leukemic cells.

In treatment of leukemia with granulocyte colony stimulating factor (G-CSF), the possibility is that G-CSF receptors on leukemic cells lead to activate its proliferation in response to G-CSF. Therefore, it is useful to know the proportions of leukemic cells with receptors for G-CSF. We used flow cytometry to estimate the proportion of such cells and normal granulocytes with G-CSF binding activity. Recombinant human G-CSF was labeled with fluorescein isothiocyanate. Granulocytes showed higher binding to the G-CSF than lymphocytes. Leukemic cells obtained from 17 to 21 patients with AML bound specifically to G-CSF, but leukemic cells with lymphoid malignancies did not. Our results showed positive correlation with date obtained by the isotopic G-CSF receptor assay. With this method, leukemic cells need not be isolated; they can be distinguished from lymphocytes or granulocytes on the cytometry screen. Radioisotopes are not needed. It is judged to be practical for the clinical laboratory.

Flow Cytometry↗
PubMed1993

Detection of bcr-abl fusion mRNA in chronic myelogenous leukemia by reverse transcription polymerase chain reaction using nested primers.

Chronic myelogenous leukemia (CML) is identified by an unique t (9;22) translocation which fuses the abl gene to the breakpoint cluster region (bcr) gene. We attempted to devise a system based on the reverse transcription-polymerase chain reaction (RT-PCR) technique using nested primer, for detection of CML-specific chimeric mRNA that would provide a practical approach for molecular diagnosis of CML. In the present study, all Philadelphia chromosome (Ph1)-positive CML samples produced positive results, while the Ph1-negative acute lymphocytic leukemia (ALL) sample and samples from normal volunteers produced negative results, indicating that this method had high specificity. We constructed a sensitive and specific system for detection of CML-specific mRNA even in minute amounts of leukemic cells that expressed bcr-abl fusion mRNA in CML patient blood. This system should be useful for clinical diagnosis of CML.

Base Sequence↗