Bayer-Symposium – serie

With the introduction of antibiotics acute inflammatory disease has ceased to be the dominant problem in general medical practice and its place is now increasingly occupied by chronic inflamma­ tory disease of which the rheumatic diseases constitute the most important group. lwo aspects of these diseases need to be consid­ ered, their aetiology and their pathogenesis. In some respects the latter is more important since even when the aetiology is known, as for example the haemolytic streptococcus in rheumatic fever, the mechanism by which the infecting agent accomplishes the development of the lesions that characterise the disease are still largely unknown. Still more so is this the case in rheuma­ toid arthritis and other chronic inflammations where the aetio­ logical agents are unknown. In an attempt to clarify the pathogenic mechanisms involved, sev­ eral attempts have been made to induce comparable lesions in ex­ perimental animals, partly to test underlying hypotheses, and partly to provide test situations for the trial of new therapeu­ tic agents. In view of the deficiencies in the current drug treat­ ment of chronic inflammatory disease there are many who feel that this is largely due to the inadequacy of the models avail­ able for test purposes.

Experimental gerontopsychology attempts to test causal hypotheses about old age-related behavioral changes by the manipulation of age-differences. An experimental treatment is introduced with the purpose of equating different age-groups with respect to a potentially relevant function. If the treatment results in an assimilation of the behavior of the different age-groups (age­ by-treatment interaction), differences in this function are con­ sidered as causal for the normally observed behavioral differ­ ence. If it does not result in an assimilation of the behavior of the different age-groups (main effect of treatment), differ­ ences in this function are considered as irrelevant for the nor­ mally observed behavioral difference. The different interpretations of age-by-treatment interactions and main effects of treatment in this kind of research are reasonable only if the experimental treatment actually results in an equalization of the age-groups with respect to the func­ tion of interest. As is shown, such a functional equalization can neither be demonstrated nor assumed in many cases. In such cases, studies with either age-group can be used to investigate hypotheses about potential causes for old age-related behavioral changes, studies with young subjects having important advantages over studies with old subjects. A test of causal relationships by age-by-treatment interactions is possible in cases where the experimental treatment evidently results in an equalization of the age groups with respect to the function in question. Unfortunately, the field of application for this kind of approach is rather limited.

G. G. Jackson The pathogenesis of bacterial infection defines the dynamics at an interface of ecologic association of bacteria and host. First, it occurs at the portal of initial contact with a per­ missive target cell. The infected cell provides either a passive or a specific receptor for the bacterium or its products, to­ gether with ligands and an environment of helper and inhibiting factors. The result is bacterial replication to produce an im­ balance of a potentially commensal relation which, under other defined conditions, would be optimal for the survival of both the host and bacterial cells. Virulence and pathogenesis are both absolute and relative terms. They must be interpreted strictly according to the circumstances of site-specific inter­ actions of bacterial and host cells, membrane composition, structure, characteristics, and environmental substances. The bacteria themselves may have, acquire, or switch on or off under certain conditions, the products or properties that produce cellular damage that we recognize as virulence. Another result of bacterial infection may be to stimulate a normal host cell function to perform at a pathophysiologic level, causing illness that we recognize as virulence. A third marker of virulence may be the ability to invade a cell or tissue barrier and produce a pathologic effect at a site that is remote from the portal of commensal association or pathologic entry.

Held at Boppard, Germany, October 3-6, 1984

These proceedings contain the papers presented at the Bayer-Symposium V which was held in Grosse Ledder on October 16-21, 1973 and which was simultaneously the Second International Research Conference on Proteinase Inhibitors. The cordial atmosphere, the frank discussions and the profitable exchange of ideas during the First International Research Conference on Proteinase Inhibitors which was held on November 4--6, 1970 in Munich were a stimulant for us to consider holding a Second Conference especially as the steadily increasing research activities in this and related fields called for a new assessment of recent efforts in proteinase inhibitor research. In the three years since the First Conference was held, this field has developed particularly in the areas of molecular aspects of protein-protein interactions and in the extension to inhibitors of nonserine proteinases and peptidases. In planning this meeting the Organizing Committee was faced with the problem of selecting a limited number of participants and we decided that it was appropriate and necessary to focus in detail on the chemistry of proteinase inhibitors, their interac­ tions with a variety of enzymes and also to invite more general papers to survey the physiological and clinical aspects of the subject which we felt would be of importance in the future.