ABSTRACT
After intraocular lens implantation, despite good clinical results, many cataract patients develop a chronic uveitis, caused by an inflammatory response to the implant. One way to improve the biocompatibility of the intraocular lens is to modify the surface by end-point heparin attachment. This study shows that complement activation caused by poly(methyl methacrylate) can be diminished by end-point heparin attachment, as demonstrated by a significant reduction in the generation of C3a and fluid phase terminal complement complexes. It suggests that assessment of complement activation is a good indicator of the biocompatibility of intraocular lenses.
Subject(s)
Biocompatible Materials , Complement Activation , Heparin/immunology , Methylmethacrylates , Blotting, Western , Complement C3c/immunology , Complement Membrane Attack Complex , Electrophoresis, Polyacrylamide Gel , Enzyme-Linked Immunosorbent Assay , Humans , Lenses, IntraocularABSTRACT
In vivo long-term stability of intraocular lens surfaces, modified by immobilized heparin, was studied. Lenses were implanted in the anterior chamber of rabbits and analyzed for surface concentration of heparin after varying periods of time up to two years. A new method using adsorption of 125iodine-labeled protamine was developed for quantitative measurements of immobilized heparin. Another assay, based on a monoclonal antibody against heparin, was also included. The study showed that surface-immobilized heparin did not degrade or desorb to any measurable degree during a two-year follow-up.
Subject(s)
Heparin/analysis , Lenses, Intraocular , Animals , Anterior Chamber/surgery , Follow-Up Studies , Longitudinal Studies , Materials Testing , Rabbits , Surface PropertiesABSTRACT
In view of the possible association between clinical symptoms in patients with acute intermittent porphyria and monopyrroles and their oxidation products, a pharmacological investigation was undertaken utilizing mice and rats as the experimental animals to further evaluate this correlation. In mice 4-ethyl-3-hydroxy-3,5-dimethyl-delta4-pyrrolin-2-one was more toxic, and 4-ethyl-5-methoxy-3,5-dimethyl-delta3-pyrrolin-2-one less toxic than kryptopyrrole in the evaluation of behavioural, hypnotic and hypothermic effects. Experiments on the development of tolerance in rats to daily injections of kryptopyrrole have been performed and could serve as a model for the spontaneous recovery occurring in patients with acute porphyria. A new method for the determination of kryptopyrrole in urine is reported. It is based on radiolabelled aldehyde reacting with kryptopyrrole. This method differed from the regular Ehrlich aldehyde reaction, although the results of both methods depend upon dilution of the urine.
