PubMed Health⌕ Search

Biomedical subjects

C Akin

Publications and source records attributed to C Akin.

25 records · Page 2Linked to original sources
PubMed1996

Stimulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) production and its role as an autocrine inducer of CD14 upregulation in human myeloid leukemia cells.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a pleiotropic cytokine that takes part in the growth and differentiation of normal and leukemic hematopoietic cells. Because of its potential significance in the etiopathogenesis of myeloid leukemia, we have studied the extracellular stimuli leading to GM-CSF secretion from a human myeloid leukemia cell line, K-562, and have demonstrated an important role for the cytokine in the differentiation process of this cell line. TNF-alpha, IL-1 beta, phorbol ester (PMA), and calcium ionophore A23187 were found to stimulate GM-CSF production from K-562 cells. PMA caused the cells to differentiate into megakaryocytic lineage, whereas treatment with A23187 resulted in increased expression of monocyte/macrophage marker CD14. Neutralization of the GM-CSF activity in the culture medium, as well as blocking of its receptors, resulted in suppression of the increase in CD14 expression and partially restored the proliferative capacity in cells exposed to A23187. Autocrine GM-CSF secretion did not appear to play an important role in PMA-induced megakaryocytic differentiation. These results suggest that autocrine GM-CSF secretion may be associated with differentiation of myeloid leukemic cells without any significant growth stimulatory activity.

Calcimycin↗
PubMed1994

Inhibition of murine splenic T lymphocyte proliferation by 2-deoxy-D-glucose-induced metabolic stress.

Female Swiss-Webster mice were injected with the glucose analogue 2-deoxy-D-glucose (2-DG), which when administered to rodents induces acute periods of metabolic stress. A single or multiple injections of 2-DG invoked a stress response, as evidenced by increases in serum corticosterone levels. The influence of this metabolic stressor on the blastogenic potential of splenic T lymphocytes was then examined. It was found that one, two, or three injections of 2-DG resulted in depressed T cell proliferative responses, with an attenuation of the effect occurring by the fifth injection. The 2-DG-induced inhibition of T cell proliferation was not attributable to 2-DG-induced cytolysis, as in vitro incubation of naive T cells with varying concentrations of 2-DG did not result in a reduction in cell number or viability, and flow cytometric analysis demonstrated that percentages of CD3, CD4, and CD8 splenic T cells were not altered as a result of 2-DG-induced stress. Incubating naive T cells in varying concentrations of 2-DG resulted in a dose-dependent inhibition of T cell blastogenic potential. Following in vivo exposure to 2-DG, T cell proliferation did not return to normal levels until 3 days after the cessation of 2-DG injections. Administering the beta-adrenergic receptor antagonist propranolol did not reverse the inhibited lymphoproliferation in 2-DG-treated mice. The inhibition in T cell proliferation was not observed, however, in mice that had been adrenalectomized or hypophysectomized and injected with 2-DG.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy↗
PubMed1993

Modulation of transferrin receptor expression by insulin and granulocyte-macrophage colony stimulating factor in AML-193 leukemic cells.

The effects of insulin and granulocyte-macrophage colony stimulating factor (GM-CSF) on the expression of transferrin receptors in AML-193 myeloid leukemia cell line were investigated. Insulin, alone or in combination with GM-CSF, caused an increase in surface transferrin receptors within 5 min. This increase was inhibited by hyperosmolarity but not by cycloheximide suggesting the involvement of receptor recycling from internal pools. In contrast, receptor increase after 18 h of incubation with insulin and GM-CSF was sensitive to cycloheximide indicating that long term effects of these growth factors are mediated through protein synthesis. These results may have implications on combined GM-CSF + antitransferrin receptor antibody therapy of leukemias.

Granulocyte-Macrophage Colony-Stimulating Factor↗
PubMed1992

Context availability and the recall of abstract and concrete words.

Predictions of an automatic-imagery, strategic-imagery, and context-availability hypothesis of concreteness effects in free recall were examined. In each experiment, recall of abstract and concrete words controlled for rated context availability was compared with the typical situation in which context availability is confounded with imageability. In Experiment 1, a directed intentional-recall task produced concreteness effects in recall. Experiment 2 compared concreteness effects in recall following three orienting tasks: imagery rating, context-availability rating, and a directed intentional-memory task. Concreteness effects in the context-availability-controlled condition were found following the imagery-rating and the directed intentional-memory tasks, but not after the context-availability-rating task. In Experiment 3, subjects reported the strategies that they used to encode the list. Subjects reporting an imagery strategy showed concreteness effects for words controlled for rated context availability, but those not reporting it did not. These results support a strategic-imagery view of concreteness effects in free recall.

Humans↗
PubMed1988

The antitumor effect of bleomycin combined with bestatin against Ehrlich ascites carcinoma in mice.

The effect of bleomycin against Ehrlich ascites carcinoma transplanted subcutaneously to mice used in combination with bestatin was investigated. Male Balb/c mice weighting approximately 20 g and bred in our laboratories were used in this study. Each mouse was injected in its left lateral abdominal region subcutaneously with 7 X 10(6) tumor cells in 0.2 ml of ascites fluid. The mice were divided into four groups: control, bestatin alone (5 mg/kg intraperitoneally on Days 9-14), bleomycin alone (10 mg/kg intraperitoneally on Days 7 and 8), and bestatin plus bleomycin. Our results show that bestatin enhances the antitumor effect of bleomycin against Ehrlich ascites carcinoma as measured by the increased survival rates. Being an agent of very low toxicity, bestatin should be considered as a part of the chemoimmunotherapy protocol.

Adjuvants, Immunologic↗