Biomedical subjects
Publications and source records attributed to W J McCune.
We assessed the effects of administration of gold sodium thiomalate on the clinical and immunologic manifestations of type II collagen-induced arthritis in rats. Injections of varying doses of gold did not alter these parameters significantly. Thus, there was no evidence in this animal model that gold possesses either antiinflammatory or immunosuppressive properties.
To determine whether emotional states could influence susceptibility to type II collagen-induced arthritis in rats, we studied the effects of experimentally produced psychological stress on the clinical, histologic, and immunologic manifestations of this autoimmune disease. Stress, induced by exposure to a cat, abrogated the development of arthritis in rats immunized with type II collagen. The incidence of arthritis was also decreased in rats subjected to transportation and handling. These environmental factors dissociated the development of humoral and cellular sensitivity to collagen from the occurrence of arthritis. This study provides a unique demonstration that psychosomatic processes can influence an animal mode of autoimmunity.
Arthritis can be induced in rats by intradermal injection of oil containing bacterial derivatives (adjuvant-induced arthritis) or cartilage collagen (type II collagen-induced arthritis). It was of interest, therefore, to determine whether collagen functions as an autoantigen in rats with adjuvant arthritis. Blood mononuclear cells from the majority of rats with adjuvant arthritis exhibited enhanced thymidine incorporation to homologous types I and II collagens, as well as to purified protein derivative of tuberculin. In contrast, cells from rats remaining nonarthritic after injection of adjuvant did not respond to collagen, although they did react to tuberculin. Similar results were obtained with a radiometric ear assay used to quantify intradermal delayed-type hypersensitivity in vivo. Using passive hemagglutination, autoantibodies to these collagens and their denatured alpha-chains were frequently detected in the sera of rats late in the course of adjuvant arthritis. Rats with inflammation of a hindlimb induced by turpentine did not acquire sensitivity to collagen. These data indicate that autoimmunity to collagen is a common feature of adjuvant- and collagen-induced arthritis, both of which are considered to be mediated by immunologic mechanisms.
This study shows that psychological stress, produced either by exposure to a predator or by movement and handling, can profoundly suppress the clinical and histologic manifestations of collagen-induced arthritis. In addition, stress can dissociate the development of humoral and cellular sensitivity to collagen from the occurrence of arthritis. Thus stress modalities provide a means of acquiring additional insights into the pathogenesis of collagen-induced arthritis in rats. Such studies may lead to a further understanding of the relationship between emotional states and the functioning of the immunologic system. This study further illustrates the need to identify and control for the effects of stress in animal studies of immunopathology. Finally, the therapeutic implications of this study for autoimmune diseases would appear self-evident (Fig. 7).
In a prospective study, 10 patients with well-documented osteoarthritis (O.A.) of the hips were imaged using spin-echo pulse sequences (TR = 0.5 to 1.5 s and TE = 28 to 60 ms). After analyzing the changes observed, an MR grading system for assessing severity of O.A. in the hips was developed. Using this grading system and an established grading system for osteoarthritis using roentgenograms (both systems use grades 0-4), two radiologists independently graded the MR studies and plain films separately, twice. The roentgenogram grading system was more accurate in predicting symptoms in the more severe cases, whereas the MR grading system was slightly more useful in the less severe cases. Our results show that MR can demonstrate a spectrum of changes of O.A. in the hips. Its ability to directly image articular cartilage makes it a powerful research and clinical tool.