Expression of Cyclooxygenase-2 in naturally occurring bovine cutaneous fibropapillomas.

Bovine cutaneous fibropapillomas are benign skin tumours characterized by epithelial and dermal proliferation and induced by Bovine papillomaviruses (BPVs). Cyclooxygenase (COX) 1 and 2 are enzymes involved in pathological conditions, such as inflammation and epithelial carcinogenesis. Here we investigated biochemically and immunohistochemically COX-2 expression in bovine cutaneous fibropapillomas. Eight of twelve fibropapillomas (67%) showed COX-2 positive immunosignal mostly in the cytoplasm of the basal cell layer, while the normal skin did not stain. Biochemical analysis confirmed the expression of COX-2 in tumour samples. This study shows COX-2 expression in cutaneous fibropapillomas, suggesting a contribution in epithelial tumour development.

Alterations in mast cell proteinases and protease inhibitors in the progress of cutaneous herpes zoster infection.

The possible involvement of mast cell proteases in the cutaneous inflammation of herpes zoster was studied histochemically in ten patients. Mast cell tryptase and chymase bioactivities were demonstrated enzyme-histochemically. The localization of protease inhibitors as well as tryptase and chymase proteins in mast cells was established using a sequential double-staining method which first demonstrated bioactive tryptase or chymase, followed by immunohistochemical identification of these antigens. Biopsies were taken from involved vesicular and erythematous skin, as well as from normal healthy-looking skin. Tryptase-bioactive mast cells were significantly lower in number in the upper, but not in the deeper dermis of vesicular skin (68 +/- 37 cells/mm2, mean +/- SD) when compared with either healthy-looking (97 +/- 38) or erythematous skin (105 +/- 36) (t-test, P < 0.005). In contrast, chymase-bioactive mast cells were significantly reduced in number both in erythematous skin (44 +/- 20, P < 0.02) and even more so in vesicular skin (26 +/- 20, P < 0.0005) when compared with healthy-looking skin (64 +/- 27). The percentage of alpha 1-antitrypsin -immunoreactive and alpha 1-antichymotrypsin-immunoreactive mast cells in the upper dermis increased steadily from the values in healthy-looking skin (37.9 +/- 18.8 and 82.5 +/- 21.6 per cent) to those in erythematous (64.4 +/- 16.4 and 93.5 +/- 7.9 per cent) and vesicular skin (75.2 +/- 10.2 and 96.4 +/- 4 per cent). A novel finding was that cells showing tryptase immunoreactivity but no enzyme activity were found in two out of nine erythematous skin specimens and in four out of seven vesicular specimens. In healthy-looking skin, all cells with chymase immunoreactivity also displayed chymase bioactivity, but only 53.2 +/- 24.25 per cent of these mast cells in erythematous lesions and 44.4 +/- 15.9 per cent in vesicular lesions showed chymase bioactivity, suggesting inactivation of chymase by protease inhibitors. These results show prominent alterations in mast cell proteinases and protease inhibitors, indicating that these enzymes participate in the cutaneous inflammation due to herpes zoster.