The activities of elastase, cathepsin G, lysozyme and myeloperoxidase of polymorphonuclear leukocytes were determined by spectrophotometry in thirty-six patients with psoriatic lesions, twelve symptom-free patients with psoriasis and fifteen normal controls. The mean activities of cathepsin G, elastase and lysozyme were found to be increased by 55 to 70% in patients with actively spreading plaque lesions compared with healthy controls (P less than 0.01). Most patients with guttate lesions had total enzyme activities within the normal range. Those with stationary plaque psoriasis had activities of both neutral proteinases (cathepsin G and elastase) which were about 40% lower than normal controls (P less than 0.05). In the lesion-free psoriatics, the activities of neutral proteinases were about 70% of control values. Our findings emphasize the importance of assessment of disease activity in this sort of investigation. The present data may help to resolve much of the confusion regarding PMN function in psoriasis.
Epithelial tumors were induced using 0.5 per cent solution of DMBA in two strains of mice--one infected with leukoviruses (Swiss mice), and the other is free of these viruses (hairless mice). Tumors from 15 mice of each strain were examined light- and electron-microscopically. Depending on the period of administration of the carcinogen, benign growths of the type of papilloma or keratoacanthoma were obtained, or malignant tumors. In the tumors in Swiss mice electron microscopy revealed a distinct increase in the numbers of viruses in comparison with surrounding skin and intact skin of healthy mice of this strain. In spite of certain histologic differences between tumors produced in Swiss and hairless mice, the results argue against a role of leukoviruses in the pathogenesis of experimentally induced epithelial tumors in mice.
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