| Project/Area Number |
63570039
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | Ehime University |
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Principal Investigator |
MAEDA Nobuji Ehime Univ., Sch. Med., Professor, 医学部, 教授 (50036464)
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| Co-Investigator(Kenkyū-buntansha) |
IZUMIDA Yoji Ehime Univ., Sch. Med., Assistant, 医学部, 助手 (50212957)
SEIKE Masahiko Ehime Univ., Sch. Med., Assistant, 医学部, 助手 (60136322)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1988: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Erythrocytes / Adhesion / Aggregation / Aging / Glycophorin / Membrane proteins / Fibrinogen / Recombinant erythropoietin / 細胞電気泳動 / フィブリノーゲン |
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| Research Abstract |
Adhesiveness of in vivo aged erythrocytes was studied by measuring (i) the velocity of erythrocyte aggregation and the dissociation of the aggregates, and (ii) the interaction of erythrocytes with artificially reproduced erythrocyte membrane on the glass plate.
(1) Human aged erythrocytes fractionated by a density gradient centrifugation with Percoll were more aggregative and more adhesive than young erythrocytes.
(2) Aggregation velocity of erythrocytes normally produced in rats was greater in plasma than that of erythrocytes produced in recombinant human erythropoietin-administered rats (in which young erythrocytes were produced in bone marrow by erythropoietin stimulation).
(3) Importance of membrane surface structure of erythrocytes, particularly, the great contribution of the structural change of glycophorin A, was shown for the erythrocyte aggregation and the adhesiveness among erythrocytes. The phenomena were proposed as a model of in vivo aged erythrocytes, with a special regard to survival of erythrocytes in circulation.
In conclusion, increased adhesiveness of erythrocytes during in vivo aging in addition to the decreased deformability contributes to the removal of these aged erythrocytes in the reticuloendotherial system. In the process of impaired passage of aged erythrocytes in the reticuloendothelial system, the structural change of surface membrane proteins of the erythrocytes (the appearance of "senescent antigen" ) is sensed by macrophages.
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