In vitro damage of basal lamina-associated anionic sites by hydroxyl radical

Electron microscopic X-ray microanalysis of metals deposited in oral mucosa

A 35-year-old woman exhibited bluish-brown discoloration of her buccal mucosa suggesting malignant melanoma. Histopathological examination revealed that the pigment was not melanin but caused by metal deposits. Electron microscopically, metallic particles were located on the lamina densa of basal laminae at mucosal epithelium, nerve fibers, and blood vessels and on the microfilaments of elastic fibers as well as in macrophages and fibroblasts. Electron microscopic point X-ray microanalysis revealed that these metallic particles were composed of Ag, Se, Fe, Co, Cu, and S. Analysis suggests that these metals were derived from dental amalgam and that the discoloration was caused by amalgam tattoo.

Activation of the oxidative metabolism in human polymorphonuclear neutrophilic granulocytes: the role of immuno-modulating cytokines

Activated polymorphonuclear neutrophilic granulocytes (PMN) play an important role in propagation of inflammatory reactions and are capable of mediating tissue damage particularly by release of reactive oxygen species and lysosomal contents. Cytokines produced by monocytes as well as epidermal cells were recently shown to modulate PMN function. Therefore, the effect of immunomodulating cytokines on the oxidative metabolism of isolated human PMN was tested by functional as well as ultrastructural criteria. The following recombinant human cytokines were tested: tumor necrosis factor (TNF alpha), lymphotoxin (TNF beta), granulocyte-macrophage colony-stimulating factor (GM-CSF), M-CSF, G-CSF, PDGF, TGF-beta, interleukin-1 (IL-1) alpha and beta, IL-2, IL-3, IL-4, IL-5, IL-6, MONAP/MOC/NAF (IL-8), interferon-alpha and -gamma. Only TNF alpha, TNF beta and GM-CSF were found to be direct stimuli of the oxidative burst in human PMN whereas IL-3, IL-5, and IL-8 were active only at extremely high concentrations. None of the other cytokines tested induced any significant effect on isolated human PMN at physiological concentrations. The results clearly demonstrate that only selected cytokines are capable of inducing a long lasting activation of PMN oxidative metabolism. Release of these mediators represents a specific signal for PMN activation in inflammatory disease states.

Effect of enzyme digestion on anionic sites and charge-selective permeability of dermo-epidermal junction

To study components of anionic sites on the lamina densa of the dermo-epidermal junction (DEJ) and to assess the effect of removal of sialic acid or glycosaminoglycans on its charge-selective permeability, epidermal sheets, whose dermis had been removed by treatment with dithiothreitol, were digested with heparitinase, chondroitinase ABC, hyaluronidase, or neuraminidase. They were then stained with polyethyleneimine for demonstration of the anionic sites or incubated in a medium containing native anionic ferritin for tracer experiments. The anionic sites were completely removed after heparitinase digestion. Although the numerical density of the sites was not altered, their electron density was decreased after chondroitinase ABC digestion. The other enzymes had no effect on the sites. In the tracer experiments, heparitinase or neuraminidase increased the number of tracer molecules penetrating into the lamina lucida of the epidermal sheet, while the other enzymes had no effect on it. These data indicate that heparan sulfate, which is a main component of the anionic sites, plays an important role in the charge-selective permeability of the DEJ, whereas chondroitin sulfate, which seems to be contained in the sites, does not, probably because of its small amount. These data also indicate that sialic acid, which is not a main component of the anionic sites demonstrated with the cationic probe, has a role in the permeability function.