Journal of biomedical materials research
-
J. Biomed. Mater. Res. · Jan 1999
Comparative StudyIn vivo evaluation of a novel alginate dressing.
Alginate dressings are currently used in the management of epidermal and dermal wounds, and provide a moist environment that leads to rapid granulation and reepithelialization. However, a cytotoxic effect on proliferation of fibroblasts and residual material with inflammation in healing wounds have been reported recently. We have developed a new alginate dressing (AGA-100), which does not have an inhibitory effect on proliferation of fibroblasts. ⋯ AGA-100 implanted into the muscle of rabbits was bioresorbed completely within 3 months. Therefore, dressing residue in AGA-100-treated full-thickness wounds might be fully absorbed in a few months. In conclusion, it is shown that our newly developed AGA-100 possesses superior properties compared with typical alginate dressings.
-
J. Biomed. Mater. Res. · Nov 1998
Poly-L-lysine amplification of protamine immobilization and heparin adsorption.
We previously reported the development of a cellulose fiber based blood filter device containing immobilized protamine (termed protamine filter) that could be used to control both heparin- and protamine-induced complications during extracorporeal therapy. To achieve enhanced heparin adsorption on the fibers, we examined the possibility of utilizing the poly-L-lysine based amplification method to augment protamine loading on the fiber, as well as to create multiple layers of immobilized protamine for heparin interaction. Results show that such a method yielded about a threefold increase in protamine loading and, consequently, about a fourfold enhancement in heparin adsorption when compared with the control without poly-L-lysine amplification. This technological improvement may facilitate development of a new generation of protamine filters with capacity and efficacy suitable for various clinical applications in extracorporeal heparin removal.
-
J. Biomed. Mater. Res. · Jun 1997
Macrophage activation and migration in interface tissue around loosening total hip arthroplasty components.
The bone-cement interface tissue of failed total hip arthroplasty (THA) has inflammatory characteristics, such as the presence of prostaglandin E2 and interleukin 1 (IL-1). We considered that the bone-cement interface tissue could be the site of granulomatous inflammation caused by a foreign-body reaction. It has been demonstrated that inflammatory cytokines and chemokines have an important role in granulomatous inflammation. ⋯ Expression of chemokine mRNAs was also commonly seen, suggesting that this led to recruitment of macrophages into the bone-cement interface tissue. Debris released from implants appears to cause activation of macrophages and the production of inflammatory cytokines and chemokines that induce cellular recruitment into interface tissue. This mechanism might form a vicious cycle that aggravates THA loosening.
-
J. Biomed. Mater. Res. · Dec 1996
Comparative StudySurface adhesion molecule expression on human blood cells induced by vascular graft materials in vitro.
The expression of surface adhesion molecules on granulocytes, monocytes (CD11a, CD11b, CD11c, CD18, L-selectin), and platelets (P-selectin, gpIIb-IIIa) was determined after incubation with different graft surfaces [expanded polytetrafluoroethylene (ePTFE) or woven Dacron]. Woven Dacron grafts upregulated the CD11b and CD11c surface antigens on both granulocytes and monocytes. Both graft materials demonstrated increased expression of CD11a and CD18 adhesion molecules on white blood cells at 30 min, followed by a downregulation. ⋯ The expression of platelet surface antigens was less clearly influenced. The clinical significance of an enhanced cell surface antigen receptor expression caused by woven Dacron (CD11b, CD11c) has to be further studied. However, determination of adhesion molecule expression might offer possibilities to predict biocompatibility.
-
J. Biomed. Mater. Res. · Dec 1996
Comparative StudySubchondral bone and cartilage repair with bioactive glasses, hydroxyapatite, and hydroxyapatite-glass composite.
The repair of an osteochondral defect in rabbit femur was studied with three kinds of bioactive glasses (BG), hydroxyapatite (HA), and hydroxyapatite-glass (HAG) composite. Seventy-two osteochondral defects were created in 18 rabbits. Sixty-four cylinders were implanted and eight defects were left empty as controls. ⋯ HAG degraded too much, glass 14 was too reactive and brittle, and the high alumina content in glass 11 disturbed its bone-bonding ability. Glass 7 and HA were the most balanced in the repair process. A special preparation method was used to retain soft tissues fairly unchanged and enable them to the observed together with hard tissues in SEM analysis.