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Biomedical subjects

N Nara

Publications and source records attributed to N Nara.

At least 109 records · Page 6Linked to original sources
PubMed1985

Membranes replace irradiated blast cells as growth requirement for leukemic blast progenitors in suspension culture.

The blast cells of acute myeloblastic leukemia (AML) may be considered as a renewal population, maintained by blast stem cells capable of both self-renewal and the generation of progeny with reduced or absent proliferative potential. Blast progenitor renewal is manifested in suspension culture by an exponential increase in clonogenic cells. This growth requires that two conditions be met: first, the cultures must contain growth factors in media conditioned either by phytohemagglutinin (PHA)-stimulated mononuclear leukocytes (PHA-LCM), or by cells of the continuous bladder carcinoma line HTB9 (HTB9-CM). Second, the cell density must be maintained at 10(6) blasts/ml; this may be achieved by adding irradiated cells to smaller numbers of intact blasts. We are concerned with the mechanism of the feeding function. We present evidence that (a) cell-cell contact is required. (b) Blasts are heterogeneous in respect to their capacity to support growth. (c) Fractions containing membranes from blast cells will substitute for intact cells in promoting the generation of new blast progenitors in culture. (d) This membrane function may be specific for AML blasts, since membranes from blasts of lymphoblastic leukemia or normal marrow cells were inactive.

Cell Division↗
PubMed1985

The proliferation in suspension of the progenitors of the blast cells in acute myeloblastic leukemia.

A minority of blast cells in acute myeloblastic leukemia (AML) form colonies in culture in methylcellulose when stimulated by media conditioned by normal leukocytes in the presence of phytohemagglutinin (PHA-LCM). Blast colonies can be replated successfully, either as pooled cells or suspensions from single colonies. However, the plating efficiency declines with repeated passages, and more than four subcultures have not been achieved. In this study, blast populations were cultured in suspension, with fetal calf serum, alpha-minimal essential medium and PHA-LCM. In cells from 17 of 18 patients, exponential growth of clonogenic blast cells was maintained for six to seven days without reculturing. Colonies obtained from progenitors taken from liquid culture and replated in methylcellulose were replated to obtain the secondary plating efficiency (PE2). In 14 cases, this value was maintained or increased. In three instances, PE2 fell following culture in methylcellulose. When cells in suspension were recultured, exponential growth continued. In nine instances, exponential growth was maintained for from seven to 70 days. During this time, PE2 was maintained. Results from experiments using velocity sedimentation separation and analysis of single colonies were consistent with the view that the increase in clonogenic cells in suspension was a manifestation of their self-renewal capacity. The observations also support a model of blast progenitor growth that contains the postulate that these are capable not only of self-renewal but also of determination-like events leading to loss of proliferative capacity.

Adult↗
PubMed1985

[The role of radiotherapy in the treatment of malignant lymphoma].

Eighty-four patients with malignant lymphoma in N.I.R.S., whose five-year survival was evaluated, were divided into two groups. The first one was treated mainly with irradiation between 1961 and 1972 (n = 36) and the second one mainly with anticancer drugs thereafter (n = 48). The survival of the second group was significantly superior to the first one: 60% vs 20% in the five-year survival rate of Hodgkin lymphoma (HL) and 40% vs 20% in non-Hodgkin lymphoma (NHL). These results were due to the systemic application of chemotherapy in the second group. On the other hand, 40% of the patients with NHL in the head and neck at stages I + II and who received radiotherapy alone survived. Through a detailed analysis of these data, the role of radiotherapy in the treatment of malignant lymphoma was discussed.

Adult↗
PubMed1984

Relationship between fibroblastoid colony-forming units (CFU-f) and hemopoietic precursor cells in normal human bone marrow.

To clarify the relationship between fibroblastoid colony-forming units (CFU-f) and hemopoietic precursor cells, simultaneous assays of CFU-f, CFU-e, BFU-e, and CFU-c from the bone marrow of 10 healthy volunteers were performed. The number of CFU-f correlated positively with CFU-e (r = 0.905, P less than 0.001) and BFU-e (r = 0.842, P less than 0.005), but not with CFU-c (r = 0.530, P greater than 0.1). These findings support the hypothesis that CFU-f is related to erythropoiesis in the steady state of hemopoietic tissue. Further studies of the relationship between CFU-f and erythroid precursor cells in patients with hematological diseases may help clarify their pathophysiology.

Adult↗
PubMed1984

Reduction of granulocyte-macrophage progenitor cells (CFU-C) and fibroblastoid colony-forming units (CFU-F) by leukemic cells in human and murine leukemia.

The number of bone marrow granulocyte-macrophage progenitor cells (CFU-C) and fibroblastoid colony-forming units (CFU-F) was significantly smaller in acute leukemia patients. To analyze the mechanism by which CFU-C and CFU-F were reduced, the study on murine myeloid leukemia was carried out. In murine leukemia, bone marrow CFU-C and CFU-F decreased in number in correlation with the proliferation of leukemic cells. Murine leukemic cells suppressed the growth of CFU-C and CFU-F in the mixed culture of leukemic cells and normal murine marrow cells. Furthermore, leukemic cell-conditioned medium inhibited the growth of CFU-F. The results show that murine leukemic cells themselves and/or humoral factors produced by them give inhibitory effects on the growth of not only CFU-C but also CFU-F.

Animals↗
PubMed1983

Additive effect of nitrogen oxides and cold stress on circulating leukocyte counts in rats.

To study the combined effect of nitrogen oxides (NOx) and cold stress on circulating leukocyte counts, the numbers of total leukocytes, neutrophils, lymphocytes, and eosinophils were counted in rats after 3 h exposure to NOx and/or cold stress. There was a tendency for both NOx and cold stress to increase the total leukocyte count and the neutrophil count, and to decrease the eosinophil count. The data indicated that the effects of NOx and cold stress were additive when they acted simultaneously.

Animals↗
PubMed1982

Effects of aclacinomycin-A on murine leukemia.

Effects of aclacinomycin-A (ACM) on leukemic cells and normal hematopoietic stem cells were studied for the purpose of evaluating the usefulness of this agent as an antileukemic agent. ACM suppressed not only leukemic colony-forming unit (LCFU) in the radiation-induced murine erythroleukemia, but also normal hematopoietic stem cells (CFU-S, CFU-C) in mice. However, LCFU was the most sensitive to ACM. After the administration of ACM at a dose of 5 mg/kg. LCFU was suppressed to 0.02 of the control on day 3 and recovered within 5 days. Splenic CFU-S and CFU-C were suppressed to the nadirs on day 2 and day 1, respectively, and they recovered within 5 days. On the basis of the differences in the sensitivities to ACM and recovery patterns between LCFU and normal hematopoietic stem cells. ACM at a single dose of 5 mg/kg was administered every 3 days (total dose of 25 mg/kg) into leukemic mice, and the increase in mean lifespan obtained 113.9%. Effectiveness of ACM in the treatment of acute leukemia was discussed.

Aclarubicin↗
PubMed1982

Granulopoietic inhibitors excreted in the urine of a patient with uterine cancer and marked leukocytosis.

An inhibitor of colony stimulating factor (CSF) was found in normal human urine and in the urine of a patient with uterine cancer and leukocytosis. The amount of inhibitor excreted in the patient's urine was inversely related to the amount of CSF excreted. Since the patient's urine contained the inhibitor in large amounts, it was used for further characterization of the inhibitor. The inhibitor was separated from CSF by DEAE-cellulose column chromatography, and precipitated by ammonium sulfate and 30-80% saturation. The result of centrifugation of the inhibitor in a NaBr solution of d = 1.21 and extraction of its solution by chloroform suggested that it is not a lipoprotein. Furthermore, it was inactivated by heating at 60 degree C. Isoelectrofocusing resolved in into two peaks of pI 6.7-8.4 (pI-7 inhibitor) and pI 4.7-5.4 (pI-5 inhibitor), both of which showed an apparent molecular weight of 80,000-90,000 upon Sephadex G-100 chromatography. Dose-response relation for CSF in the presence of the inhibitor(s) showed that the action of the inhibitor(s) was not due to specific inactivation of CSF. Both pI-05 and pI-7 inhibitor fractions showed mitogenic activity to mouse spleen cells in culture, and only slightly inhibited [3H]thymidine uptake in the PHA or LPS stimulated spleen lymphocytes. The result suggests that the granulopoietic inhibitor(s) obtained above is not a non-specifically cytotoxic substance(s).

Aged↗
PubMed1982

Effects of chloramphenicol on hematopoietic inductive microenvironment.

Effects of chloramphenicol (CP) on hematopoietic inductive microenvironment (HIM) were studied using in vitro and in vivo assay systems. HIM was represented as fibroblast colonies (CFUF) in in vitro culture. CP suppressed the growth of not only granuloid committed progenitor cells (CFUC), but also CFUF in in vitro culture at the concentration of 10, 50 and 100 micrograms/ml. To analyze the function of HIM in vivo, the subcutaneous bone implantation method was used. The recovery of hematopoietic stem cells in subcutaneously implanted femora of mice, which were treated with a 500 mg/kg dose of CP daily for 6 days, was significantly decreased compared to the sham treated group. Suppressive effect of CP on HIM was shown. The important role of the derangement of HIM on the pathogenesis of CP-induced aplastic anemia was discussed.

Anemia, Aplastic↗