摘要:
Water-soluble macromers including at least one hydrolysable linkage formed from carbonate or dioxanone groups, at least one water-soluble polymeric block, and at least one polymerizable group, and methods of preparation and use thereof are described. The macromers are preferably polymerized using free radical initiators under the influence of long wavelength ultraviolet light or visible light excitation. Biodegradation occurs at the linkages within the extension oligomers and results in fragments which are non-toxic and easily removed from the body. The macromers can be used to encapsulate cells, deliver prophylactic, therapeutic or diagnostic agents in a controlled manner, plug leaks in tissue, prevent adhesion formation after surgical procedures, temporarily protect or separate tissue surfaces, and adhere or seal tissues together.
摘要:
SOD and other active oxygen inhibitors are directly applied in combination with a barrier material at local sites of tissue injury to prevent or decrease formation of adhesions and undesirable proliferation of cells. Preferred barrier materials are polymeric hydrogels providing controlled release of AOI which are directly applied to the afflicted tissue. Examples demonstrate the effects of SOD on pelvic adhesions in the rat when administered by intraperitoneal (I.P.) bolus and by localized sustained release from a topically applied hydrogel system.
摘要:
A method and apparatus for molding polymeric structures in vivo is disclosed. The structures comprise polymers that may be heated to their molding temperature by absorption of visible or near-visible wavelengths of light. By providing a light source that produces radiation of the wavelength absorbed by the polymeric material, the material may be selectively heated and shaped in vivo without a corresponding heating of adjacent tissues or fluids to unacceptable levels. The apparatus comprises a catheter having a shaping element positioned near its distal end. An emitter provided with light from at least one optical fiber is positioned within the shaping element. The emitter serves to provide a moldable polymeric article positioned on the shaping element with a substantially uniform light field, thereby allowing the article to be heated and molded at a desired treatment site in a body lumen.
摘要:
A method for making a radially expandable stent for implantation within a body lumen having a generally cylindrical body with open proximal and distal ends, the cylindrical body comprising a plurality of metal elements joined to allow flexing of the cylindrical body along the longitudinal axis of the body whereby the stent can conform to a curved body lumen and a polymeric film applied to the cylindrical body such that it extends between the metal elements of the stent. Therapeutic substances may be incorporated within the applied film. The stent provides a biocompatible polymeric surface to contact and support a body lumen and also a flexible structure to allow the stent to conform closely to bends in a body lumen. The stent is especially useful for repairing an injury to blood vessels caused during angioplasty procedures.
摘要:
A radially expandable stent for implantation within a body lumen having a generally cylindrical body with open proximal and distal ends, the cylindrical body comprising a plurality of metal elements joined to allow flexing of the cylindrical body along the longitudinal axis of the body whereby the stent can conform to a curved body lumen and a polymeric film extending between the metal elements of the stent. The stent provides a biocompatible polymeric surface to contact and support a body lumen and also a flexible structure to allow the stent to conform closely to bends in a body lumen. The stent is especially useful for repairing an injury to blood vessels caused during angioplasty procedures.
摘要:
By reacting polyamines with cyclic carbonates, di-poly-(hydroxyalkyl urethanes) are produced. These diols and polyols are particularly useful for the synthesis of polyurethanes by reaction with diisocyanates or polyisocyanates.
摘要:
A cardiac pacing lead or other stimulation lead carrying a steroid compounded within a polymer matrix. The steroid is dispersed in thermoplastic or thermoset polyurethane or polyurea forming monomers or prepolymers. The mixture is then chain extended by addition of the appropriate difunctional or multifunctional isocyanate, hydroxyl or amine curing agent to form a solid polymer. The resulting formulation is molded or cast into a desired shape, and incorporated in the distal end of a medical electrical lead, adjacent to or within the electrode. In a preferred embodiment, the medical lead employs an extendable helix which is screwed into body tissue, and the polymer containing the drug takes the form of a generally dimensionally stable annular member mounted to the lead, encircling the helix.
摘要:
Novel cathode materials for use in electrochemical cells are disclosed. The cathode materials consist essentially of a conductive solution comprised of iodine dissolved in a mixture of two organic pyridine-based constituents, both of which function as donors to form complexes with iodine. Preferably, the cathode materials further include, in addition to the dissolved iodine, an iodine solid phase suspended therein. Large amounts of the iodine solid phase, relative to the dissolved iodine, may be used.