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For fair Caucasian skin, the minimal delayed erythema dose (MED) 24 hr after exposure to broadband UVA is about 1200 times greater than the MED of broadband UVB, for both single and multiple daily exposures. Repeated daily exposure to doses less than MED results in cumulative effects manifest by gradual lowering of the daily dose threshold for delayed(More)
Ultrastructural studies were carried out on the invasive nodule of forty malignant melanomas. The findings support the concept that the fine structure of lentigo maligna melanoma is often characteristic, and differs from that of superficial spreading and nodular melanoma. The melanosomes in lentigo maligna melanoma are usually ellipsoidal and resemble those(More)
An 8-month-old male infant had fever, polymorphonuclear leukocytosis, and tender, firm, elevated erythematous plaques on his face, trunk, and extremities. Histologic examination revealed a dense, perivascular, polymorphonuclear, inflammatory cell infiltrate with nuclear dust in the dermis and intrafollicular abscesses. The rash responded promptly and(More)
Previous studies on skin topically photosensitized with trimethylpsoralen and subsequently irradiated with long-wave UV light have demonstrated an increase in melanosome size and changes in the distribution patterns of melanosomes, suggesting the possibility of gene derepression or the induction of a somatic mutation of melanocytes. The present(More)
The significance of sun exposure in the pathogenesis of basal cell carcinoma (BCC) was assessed. A total of 262 tumors were studied. Most of the tumors occurred in patients over 40 years of age, with a male to female ratio of 3:2. The majority of tumors were present on the head and neck, mostly on sites maximally exposed to sun. Solar elastosis of varying(More)
Nine patients with extensive pityriasis alba were studied using histopathological and histochemical techniques and electron microscopy. There was a reduction in the density of functional melanocytes in the affected areas without any change in their cytoplasmic activity. The melanosomes tended to be fewer and smaller, but their distribution pattern in the(More)
Superantigens are powerful T lymphocyte-stimulating agents that are believed to contribute to the pathogenesis of certain diseases such as psoriasis. Toxins produced by Streptococcus pyogenes and Staphylococcus aureus are superantigens. The aim of this study was to detect genes that code for superantigens in Streptococcus and Staphylococcus aureus isolates(More)