D-Penicillamine Metabolism in an In-Vivo Model of Inflamed Synovium

Oxidation to disulphides is the chief metabolic transformation of D-penicillamine (D-pen) in patients with rheumatoid arthritis. Oxidation also occurs in many biological fluids in-vitro. Reduction of oxygen species may accompany the oxidation of D-pen under appropriate conditions and may mediate the anti-rheumatic action of D-pen. The transformation of D-pen therefore was examined in an in-vivo model of inflamed synovium. Subcutaneous air-pouches of groups of rats were treated with saline, 10% serum or 10% zymosan activated serum (ZAS). The transformation of D-pen to low molecular weight (LMW) metabolites and protein conjugates within the pouch was then assessed. The concentrations of total protein were significantly higher in the serum and ZAS-treated groups than in the saline-treated group and the inflammatory cell counts were significantly higher in the ZAS-treated group than in either of the other groups, as expected. D-pen oxidised rapidly to LMW metabolites and smaller amounts of D-pen-protein conjugate (D-pen-protein) in the air pouches of all animals. The rates of oxidation to LMW metabolites were greater in the ZAS-treated animals than the saline-treated group (p less than 0.005). The concentrations of D-pen-protein conjugate were also greater for the serum-treated and ZAS-treated animals than for the saline controls (p less than 0.005 in each case) at all times. Oxidation of D-pen therefore occurs at this site of inflammation and is influenced by local conditions. This may be important to understanding the forms in which D-pen exists in inflamed synovial joints and the way it may exert its antirheumatic activity

Mechanism of cellular rejection in transplantation

The explosion of new discoveries in the field of immunology has provided new insights into mechanisms that promote an immune response directed against a transplanted organ. Central to the allograft response are T lymphocytes. This review summarizes the current literature on allorecognition, costimulation, memory T cells, T cell migration, and their role in both acute and chronic graft destruction. An in depth understanding of the cellular mechanisms that result in both acute and chronic allograft rejection will provide new strategies and targeted therapeutics capable of inducing long-lasting, allograft-specific tolerance