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Biomedical subjects

E William Rosenberg

Publications and source records attributed to E William Rosenberg.

5 recordsLinked to original sources

Sunscreen ingredients inhibit inducible nitric oxide synthase (iNOS): a possible biochemical explanation for the sunscreen melanoma controversy.

Sunscreen products are rated upon their ability to inhibit visible redness of the skin 24 h after measured doses of ultraviolet (UV) exposure (Sun Protection Factor, SPF). Although sunscreens prevent UV-induced redness, their ability to protect against melanoma or the development of moles is less clear. UV-induced redness occurs in part by the action of nitric oxide (NO), synthesized in the skin. NO is also an important immunoregulatory molecule in the induction of the cell-mediated tumour immune response. In this study, various sunscreen ingredients were tested for their ability to inhibit the production of NO. Four of the five sunscreens tested directly inhibited the conversion of arginine to citrulline by inducible nitric oxide synthase (iNOS) in vitro. These findings suggest that sunscreens may prevent redness partly by UV absorption and partly by inhibition of the skin's inflammatory response. As such, sunscreens might promote instead of protect against melanoma.

Arginine↗

Skin basement membrane zone: a depository for circulating microbial antigen evoking psoriasis and autoimmunity.

BACKGROUND: Elevated levels of antibody to streptococcal exoenzymes have been found in patients with psoriasis or psoriatic arthritis. Research on the role of streptococcal antigen in psoriasis has been hampered by a potential molecular mimicry between streptococcal epitopes and human epidermal keratin. OBJECTIVE AND METHODS: Evidence of microbial product was sought in skin biopsies of psoriasis patients thought clinically to have either streptococcal carrier state or gastrointestinal candidal colonization. A polyclonal antibody to streptococcal-derived exoenzymes unlikely to share antigenic structures with normal human skin, and an anticandidal antibody, were used with linked streptavidin biotin amplification stain. RESULTS: The predicted microbial product appeared heavily in lesional epidermis, but unexpectedly also as a thin deposit along the skin basement membrane zone (SBMZ) of apparently unaffected skin. Staining was negative for nonpsoriatic subjects. CONCLUSIONS: The findings support a direct effect of microbial antigen in psoriasis. They also suggest an important role for SBMZ as a very large adhesive surface in the first step of a process of percutaneous epidermal elimination of foreign antigens and microbial toxins. The many autoimmune phenomena seen so often at the SBMZ are probably a physiologic part of this important immune function. Efforts to enhance the adhesive properties of SBMZ should be exploitable for both diagnostic and therapeutic benefit.

Antigens, Bacterial↗