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Biomedical subjects

M T Zaim

Publications and source records attributed to M T Zaim.

27 records · Page 2Linked to original sources
PubMed1988

In situ evidence for the involvement of superoxide anions in cutaneous porphyrin photosensitization.

Dihematoporphyrin ether, also known as Photofrin-II (Pf-II) is currently used in the diagnosis and management of a variety of epithelial neoplasms, in a modality known as photodynamic therapy (PDT). A major drawback of these porphyrins for PDT is their ability to evoke prolonged cutaneous photosensitization. The mechanism of tumor ablation and cutaneous photosensitization by these photosensitizers is thought to relate to the generation of one or more reactive oxygen species such as superoxide anion, singlet oxygen and hydroxyl radical. However, the role of these oxygen species has not been established unequivocally. In this study, the mechanism of Pf-II-mediated cutaneous photosensitization was examined using murine ear swelling as a marker. The mice treated with Pf-II and light demonstrated two-fold enhancement of ear swelling whereas animals treated with the SOD mimic, beta-carotene and dimethyl sulfoxide (DMSO) had considerably less ear swelling (p less than 0.01). The observed protective effect was dependent on the dose of each quencher and followed the pattern SOD mimic DMSO beta-carotene. The histopathologic alterations caused by Pf-II photosensitization were significantly alleviated by pretreatment with SOD mimic whereas beta-carotene and (DMSO) were less effective. Inhibitors of superoxide dismutase (sodium diethyldithiocarbamate) and catalase (hydroxyl amine and 3, amino 1,2,4-triazole) augmented Pf-II-mediated cutaneous photosensitization. These data provide the first in vivo evidence for the involvement of superoxide anion in cutaneous porphyrin photosensitization.

Animals↗
PubMed1988

Signet-ring clear-cell basal cell carcinoma.

Basal cell carcinoma displays a myriad of histopathologic variants, some of which are related to the different lines of differentiation, vis-a-vis, squamous, pilar, eccrine, or sebaceous. We herein report an example of a rare signet-ring, clear-cell variant. Our diagnosis is primarily based on the histopathologic features of the tumor, namely, the dermal nests of tumor cells with peripheral palisading and focally retracted fibroblastic stroma. Several nests are folliculocentric. The tumor cells are glycogen-rich, mucin-negative, pankeratin-positive, cytokeratin-negative, S100 protein-negative, and carcinoembryonic antigen-negative. Based on the histopathology and the results of the special stains we propose that the signet-ring clear-cell variant of basal cell carcinoma is differentiating in the direction of the outer root sheath cells of the pilar structure.

Aged↗
PubMed1988

Natural history of melanocytic nevi.

The natural history of common acquired nevi begins with junctional nevi, which first evolve into compound nevi and then intradermal nevi. The clinical appearance and histopathology of these lesions permit precise identification. Spitz nevi, blue nevi, congenital nevi and dysplastic nevi represent subcategories that also have easily identifiable features. An understanding of the nature of benign nevi makes it easier to identify potentially life-threatening melanomas.

Humans↗
PubMed1987

Carbon dioxide laserabrasion: a new approach to management of familial benign chronic pemphigus (Hailey-Hailey disease).

Familial benign chronic pemphigus (FBCP), or Hailey-Hailey disease, can be a debilitating condition. Treatment is palliative and only excision of lesional skin followed by split-thickness grafting may be curative. The success of surgery is attributed to the removal of adnexal structures and a decrease in sweating and maceration. This is the first report of successful carbon dioxide (CO2) laserabrasion of a patient with FBCP. The procedure spared the underlying adnexae which contributed to the reepithelialization of the epidermis. The selective destructive property of the CO2 laser may contribute to understanding the pathophysiology of FBCP.

Carbon Dioxide↗
PubMed1987

An immunopathological study of herpes-associated erythema multiforme.

Any pathogenetic mechanism proposed for erythema multiforme (EM) must account for the prominent mononuclear cell infiltrate in the skin lesions. The purpose of this study was to characterize immunopathologically, with monoclonal antibodies to human leukocyte antigens, the inflammatory cells in early target lesions of recurrent herpes-associated EM. Cryostat sections of snap-frozen skin biopsies were studied by the avidin-biotin immunoperoxidase technique with use of the following monoclonal antibodies: anti-HLA-DR, anti-Leu M5, anti-Leu 4 + 5b, anti-Leu 3a + 3b, anti-Leu 2a, anti-Leu 14, and anti-Leu 6. The dermal mononuclear inflammatory infiltrate in the EM biopsies consisted of monocyte-macrophages and T-lymphocytes, with both helper and suppressor T cells present. Both the dermal inflammatory infiltrate and the overlying keratinocytes were strongly HLA-DR positive. No definite alteration of Langerhans cell number or distribution was noted. These findings are consistent with the characteristics seen in cell-mediated immune reactions in the skin and point to this as a likely immune mechanism for the tissue damage of EM.

Adult↗