British Society for Dental Research

214.) 103 Stimulation of human neutrophil chemiluminescence by three anaerobic cocci. M.J.Kowolik" G.L.F. Smith and C.G.Cumming. Dept. Restorative Dentistry, University of Leeds and Dept. of Oral Medicine, University of Edinburgh. Activation of the oxygen-dependent microbicidal system of neutrophils can be monitored via the resultant chemiluminescence (CL). We have previously studied the mechanisms of CL generation in both peripheral blood and gingival crevicular neutrophils and also used this phenomenon to investigate the interaction between the neutrophil membrane and various bacterial species, isolated antigens and mineral dusts. This report describes a further such investigation, comparing the neutrophil CL produced by three gram positive, anaerobic cocci to that generated by PMA and a group B Streptococcus, serotype III. All assays were performed under standardised conditions using an LKB 1251 luminometer, with bacteria both opsonised and non-opsonised and lucigenin and/or luminol as reaction intermediates. There were marked differences in the ability of the five stimulants to elicit CL from the neutrophils but, as in previous studies, all produced greater CL output per cell fi om the gingival crevicular neutrophils. The bacteria tested were thus capable of triggering a basic host defence mechanism in vitro and analysis of the results indicated that the three anaerobic cocci tended to stimulate superoxide anion production while the group B streptococcus enhanced myeloperoxidase mediated CL. 106 tro fibrinolytic activity in epithelsal cells derived fromOral carcinomas. Y BarlowDepartmeni of Oral Medicine and Oral PathologyEdinburgh UniversityEDINBURlH. Malignancy is associated with enhanced in vivo fibrinolytic activity of tissues,plassa and body fluids.The enzymatic composition of tuaours is also shifted to favour proteolysis and hence potential invasiveness of the tumour.Pl ascin is further capable by converting latent collagenases of degrading components of the pericellular matrix and basal lamina. Many in vitro studies indicate that these proteases are Involved in cellular alterations that are related to growth control and malignant transformation but not all have demonstrated a positive correlation between increased plasminogen accvator acvtivity and the transformed state. In this study,fibrinolytic activity was assessed in pure populations of epithelia] cells derived from normal oral cucosa and oral carcinomas grown in the absence of cesenchye support.Cultures,2-4wk old,were used throughout.The number of epithelial cells per plate was estimated using a point counting method and after 2d in serum free medium the culture supernatants were harvested.These were tyophilised and resuspended in a known volume before assaying plasminogen activator activity using the chromogenic substrate S2251.0ver 701 of the activity could be quenched by specific inhibitors of plascinogen activator)NPGB) and plasinleACAt)in culture supernatants.A three fold decrease in the amount of plasminogen activator activity was found in supernatants of tuiour derived cells compared to normal epithelial cellstherefore there appeared to be no intrinsic increase in expression of plascinogen activator synthesis in these malignant cells. British Division 10 Factors affecting tooth staining with metal salts and Chlorhexidine (CG). M. Addy, F. Al-Arrayed and J. Moran.* Department of Periodontology, Dental School, Heath Park, Cardiff. There is considerable variation in tooth staining between individuals following oral intake of metal salts or chlorhexidine. Moreover this variation cannot be entirely explained by just differences in intake of dietary chromogens. This study was undertaken to assess the influence of possible factors which could affect stain accumulation. By measuring precipitation reactions or staining of acrylic blocks and teeth with tea, the following factors were studied. (1) Temperature, (2) concentration of chlorhexidine or metal salts, (3) mechanical cleaning by toothpaste slurries or brushing with CG or toothpaste The results of this study showed that variations in staining reactions were apparent with (1) different temperatures (2) different concentrations of CG, di and trivalent metals but not mono talent metals (3) the mechanical cleaning procedures described. These findings would suggest that (1) differences in staining between individuals may be accounted for by these factors (2) clinical staining may be reduced by altering any of these factors for