1998 Fiscal Year Final Research Report Summary
Development of the defecation pacemaker using artificial muscle
| Project/Area Number |
08557075
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
General surgery
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| Research Institution | Keio University |
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Principal Investigator |
YOKOYAMA Jotaro Pediatric Surgery School of Medicine Keio University, Associate Professor, 医学部, 助教授 (80051407)
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| Co-Investigator(Kenkyū-buntansha) |
HOSHINO Ken Pediatric Surgery, Medical school Keio University, 医学部外科, 助手 (70190197)
MATSUFUJI Hiroshi Pediatric Surgery St.Luke's International Hospital, 小児外科, 副医長(研究職) (80190502)
ONISHI Seijin Terumo..K.K., 研究開発センター開発研究所, 研究員
WATANABE Shuichi Physiology, School of Medicine Keio University, Associate Professor, 医学部・生理学, 助教授 (60138120)
OSADA Yoshihito Division of Biological Science Graduate School of Science Hokkaido University, P, 大学院・理学研究科生物学, 教授 (60007804)
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| Project Period (FY) |
1996 – 1998
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| Keywords | intelligent gel / artificial muscle / anal sphincter / colon / rectum / defecation / sacral nerve / fecal incontinence |
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| Research Abstract |
1. Motility patterns of the colon and anorectum during spontaneous defecation.
(1) Migration of giant contraction of the colon to the rectum (2) rectal relaxation-contraction sequence (3) anal sphincter relaxation play important roles during defecation.
2. Responses of the colon and anorectum to the first or second sacral nerve electric stimulation
(1) The colon shows contractions propagated distally. (2) The rectum isrelaxed or contracted. (3) The internal anal sphincter is relaxed. These responses are similar to the motility patterns observed during spontaneous defecation.
3. Possibility of the intelligent gel as an artificial anal sphincter The intelligent gel is prepared by the radical polymerization of methylacrylate and stearylacrylate. It exhibits the reversible transition of mechanical properties by the change of temperature at 38ﾟC.While the modulus and elasticity of this gel is very high and low, respectively, at 35ﾟC, it can be extended highly by the low force at 40ﾟC.Namely the intelligent gel can show the similar mechanical behavior as the muscle. A tube shaped artificial anal sphincter 2.0 cm in diameter ; 2.0 cm long is made of the gel. The canine colon is pull through it. The giant contractions of the colon propel the fecal material and widen the artificial sphincter to evacuate it at a temperature 4OﾟC.The sphincter returns to the original shape when the colon is emptied. The contraction fails to widen the gel and the contents is not expelled at a temperature 35ﾟC.
These findings suggest two possible systems to control defecation and to maintain continence.
(1) The sacral nerve stimulator to induce defecation for the patients with central nervous system problems.
(2) The pacemaker systems, which detect the giant contraction of the colon and heat the gel simultaneously for the patients who, loosed the function of the anorectum.
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