1995 Fiscal Year Final Research Report Summary
STRUCTURE AND FUNCTION OF POLYSACCHARIDES AND THEIR MIXTURES
| Project/Area Number |
06045007
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | University-to-University Cooperative Research |
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| Research Institution | GUNMA UNIVERSITY |
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Principal Investigator |
ARAI Kozo GUNMA UNIVERSITY,Faculty of Engineering, Professor, 工学部, 教授 (60008456)
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| Co-Investigator(Kenkyū-buntansha) |
MENZIES Alan R THE NORTH EAST WALES INSTITUTE,Assistant, 助手
WILLIAMS Peter A. THE NORTH EAST WALES INSTITUTE,Associate Professor, 助教授
PHILLIPS Glyn O. THE NORTH EAST WALES INSTITUTE,Professor, 教授
YOMEYAMA Masaru GUNMA UNIVERSITY,Faculty of Engineering, Assistant, 工学部, 助手 (40230841)
TAKIGAMI Shoji GUNMA UNIVERSITY,Faculty of Engineering, Assistant, 工学部, 助手 (70143203)
KUBOTA Hitoshi GUNMA UNIVERSITY,Faculty of Engineering, Associate Professor, 工学部, 助教授 (20089816)
ARAI Kenichiro GUNMA UNIVERSITY,Faculty of Engineering, Associate Professor, 工学部, 助教授 (50008455)
KOMOTO Tadashi GUNMA UNIVERSITY,Faculty of Engineering, Professor, 工学部, 教授 (00016643)
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| Project Period (FY) |
1994 – 1995
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| Keywords | heparin / molecular weight / APTT / AT-III / desulfation / hylan / A.senegal / DSC / freezing-bound water |
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| Research Abstract |
A powdered sodium-heparin (Mn=8000) was irradiated at the dose rate of 10kGy/pass in air at room temperature. The Mn values decreased sharply until about 500kGy and then leveled off at about 4500, which continued to 2,500kGy at the total dose. The polydispersity (Mw/Mn) decreased in approximately proportional to the dose, i. e., 1.52 for the heparin with 0 dose to 1.22 for 2,500kGy. The free amino and hydrxyl group contents were not changed until the total dose of about 500kGy, but significantly increased with the increase of the total dose. It was suggested that the main chain scission of heparin molecules predominates in the region of lower irradiation dose, and subsequent desulfation generates at higher dose. It was found that for the samples irradiated below 150 kGy, the APTT activities increased up to about 30% in maximum as compared with the unirradiated heparin (166u/mg), while the AT-III activities almost unchanged. The molecular-weight effect on the APTT activity was demonstrated. Over the dose of 150 kGy, both activities greatly decreased. An important suggestion was abtained that the decrease of the activity is due to the desulfation from N-and O-sulfate groups in heparin.
The water binding characteristics of hylan (cross-linked hyaluronic acid) are compared with another cross-linked polysaccharide Acacia senegal gum exudate (A.senegal) using differential scanning calorimetry (DSC). Both polysaccharide systems bind water effectively, and the transitions characteristic of two types of freezing-bound water can be distinguished from the melting or freezing of free water. There is evidence for the existence of metastable states of freezing-bound water within the two systems. A.senegal binds considerably less freezing-bound water than hylan systems and dose not have the same ability as hyaluronic acid to form structured entangled networks which can incorporate water with in the matrix.
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Research Products
(14 results)
