Grant-in-Aid for Developmental Scientific Research (B)
|Allocation Type||Single-year Grants|
|Research Institution||YOKOHAMA CITY UNIVERSITY SCHOOL OF MEDICINE|
WADA Jiro(1991-1992) YOKOHAMA CITY UNIVERSITY SCHOOL OF MEDICINE, DEPARTMENT OF ORTHOPAEDIC SURGERY,ASSISTANT INSTRUCTOR, 整形外科, 助手 (00220955)
森井 孝通(1990) 横浜市立大学, 整形外科, 助手 (00174392)
IIJIMA Tomohiko SUMITOMO CEMENT CO.LTD, LABORATORY CENTER, INVESTIGATOR, 中央研究所, 研究員
OKU Takashi SUMITOMO CEMENT CO.LTD, LABORATORY CENTER,HEAD, 中央研究所, 主任研究員
KIMIJIMA Tateyuki SUMITOMO CEMENT CO.LTD, LABORATORY CENTER,HEAD, 中央研究所, 主任研究員
SHIODA Yuji SUMITOMO CEMENT CO.LTD, LABORATORY CENTER,HEAD OFFICER, 中央研究所, 所長
GOTO Hachiro YOKOHAMA CITY UNIVERSITY SCHOOL OF MEDICINE, DEPARTMENT OF ORTHOPAEDIC SURGERY,A, 整形外科, 助手 (50234993)
茂 啓二郎 住友セメント株式会社, 中央研究所, 研究員
和田 次郎 横浜市立大学, 整形外科, 助手 (00220955)
|Project Period (FY)
1990 – 1992
Completed(Fiscal Year 1992)
|Budget Amount *help
¥9,700,000 (Direct Cost : ¥9,700,000)
Fiscal Year 1992 : ¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1991 : ¥4,700,000 (Direct Cost : ¥4,700,000)
Fiscal Year 1990 : ¥2,800,000 (Direct Cost : ¥2,800,000)
|Keywords||HYDROXYAPATITE / THERMAL DECOMPOSITION PRODUCT / BONE CEMENT|
Hydroxyapatite thermal product was hardened by mixing with water solution (HAp cement). After hardening, HAp cement became pure hydroxyapatite again. This new biomaterial was investigated with respect to (1)affinity to bone, (2)mechanical strength, (3)biological safety, and (4)histological reaction in the ovariectomized rat's femur.
(1)HAp cement was injected into the femora of twenty-eight rabbits. The injected decomposition product was confirmed to be solid and pure HAp by X-ray diffraction of two, four, nine and twelve weeks after injection. Histological examination revealed new bone formation in direct contact with the surface of HAp cement more than two weeks after injection. HAp cement apparently has a good affinity to bone.
(2)The mechanical strength of HAp cement was measured three days, one, and four, and eight weeks after injection into the femur of rabbits. A compression test with femur cut from the injected site revealed that hardened HAp cement did not break under a compress
ion force up to 50MPa; that strength was corresponds to 70% of PMMA. HAp cement was stronger than PMMA cement in the case of a push-out test. (3)We investigated the biological safety of HAp cement. In the Acute test, water extracted from HAp cement preserved in a saline water was injected into the vein of rats. No acute toxicity was seen. in the Subacute test, HAp cement was inserted into the subcutaneous, intraperitoneal, and intramuscular tissues of rats. Those rats were sacrificed one, two, and four weeks after injection. General state, blood examination, and histological inspection didn't indicate subacute toxicity of HAp cement. In the Chronic test, HAp cement was injected into eighteen rabbits using the same method as (1). Half the rabbits were sacrificed twenty-six and half fifty-two weeks. The items investigated were the same as in the subacute test, and it was revealed that HAP cement has no chronic toxicity.
(4)HAp cement was injected into the femur of ovariectomized rats (an osteoporotic model in rats). New bone formation was seen at the injected site more than eight weeks after injection, in contrast to four weeks in the control rats. But even in the ovariectmized rats, the area of new bone formation increased gradually. That indicated HAp cement also has a good osteoconductility.
It is expected that HAp cement can be successfully applied clinically as a bioactive bone cement. Less