Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Bone
Patent
1990-09-07
1993-11-23
Isabella, David
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Bone
128DIG8, 424428, 514801, A61F 204
Patent
active
052639835
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to cell-penetrable medical material easily assimilable into living tissues and useful as artificial tissues. Further, the present invention also relates to application of this medical material to artificial skin.
BACKGROUND ART
Implantation is very effective for treating deficiency occurred in part of tissues or irreversible function deficiency. For avoiding the problem of immune incompatibility known as rejection, in this case, it is preferable to transplant the tissue coming from other regions of the patient or his relatives, namely allotransplantation. However, such favorable implanting tissues are not always available. So, such studies for providing implantable artificial tissues have heretofore been made.
First approach for getting artificial tissues free of rejection is to provide the material having low histological reactivity, namely the material which fails to sensitize the tissue and immunocellular system. An example of this approach is the study to enhance hydrophobicity of the synthetic polymer material represented by polyurethanes.
Second approach is to provide the material which is capable of assimilating rapidly into the tissue before inducing the immunoreaction thereby functioning as a part of an organ. More particularly, it is to construct the tissue similar to connective tissues by penetrating such a cell having the tissue-healing function as fibroblast into the material coming from living bodies such as collagen. Since the new tissue thus formed is no longer not-self, no immune incompatibility would take place. Therefore, it can be said that this approach is more ideal than the first approach.
However, said second approach has the following defects.
Artificial materials consisting of collagen or the like derived from living bodies show high affinity to cellular tissues, but would be easily decomposed by collagenase or other enzymes within the living bodies. Therefore, there cannot be sufficiently kept the time for the penetration of fibroblast or the like to construct new tissues. So it is necessary to enforce the physical properties of the material by introducing cross-linking with any means, in order that the material may resist against the decomposition due to collagenase. Dehydrating cross-linking under heating or chemical cross-linking with chemicals can be adopted therefore. Of these cross-linking methods, the dehydrating cross-linking is safer than the chemical treatment, but less resistant against collagenase than the chemical cross-linking. Therefore, it is general that the chemical cross-linking is adopted singly, otherwise a combination of the chemical cross-linking and the dehydrating cross-linking is adopted.
Resistance against collagenase is markedly improved by introducing the cross-linking structure by said methods. For example, when the cross-linking structure is introduced into a collagen by merely dehydrating the collagen under heating at 110.degree. C. in vacuum for 24 hours, the cross-linked collagen is dissolved within one day by allowing to stand at 37.degree. C. in 3 unit/ml collagenase solution. On the contrary, the collagen obtained by introducing the cross-linking structure with an isocyanate type cross-linking agent does not show any change on appearance in 7 days even by allowing to stand still at 37.degree. C. in 1000 unit/ml collagenase solution.
On the other hand, introduction of said strong cross-linking structure would lower markedly the good affinity to cells or tissues, which is an inherent property of the collagen. Therefore, the penetration of cells would be inhibited to accompany a problem that the new desired tissues could not be formed.
As stated above, it is difficult to suffice both the requirement of good resistance to enzymes and the requirement of good affinity to cells or tissues in materials derived from living bodies such as collagen. Therefore, while the second approach is very attractive, no medical material sufficing the requirements has been developed yet.
The cell-penetrable medical ma
REFERENCES:
patent: 3322632 (1967-05-01), Schwick
patent: 3767437 (1973-10-01), Cruz, Jr.
patent: 4164559 (1979-08-01), Miyata et al.
patent: 4276281 (1981-06-01), Crihelair
patent: 4280954 (1981-07-01), Yannas et al.
patent: 4522753 (1985-06-01), Yannas et al.
patent: 4642117 (1987-02-01), Nyugen et al.
patent: 4703108 (1987-10-01), Silver et al.
patent: 4749689 (1988-06-01), Miyata et al.
patent: 4970298 (1990-11-01), Silver et al.
Katakura Takeo
Koide Mikio
Konishi Jun
Mori Yuichi
Ohsaki Ken-ichi
Gualtieri Gina M.
Isabella David
Terumo Kabushiki Kaisha
LandOfFree
Medical material and prosthetic skin in which cells can invade does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Medical material and prosthetic skin in which cells can invade, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Medical material and prosthetic skin in which cells can invade will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1845044