CiltHekimi.Com - Ana Sayfa

Menü

Duyurular

www.serkantorun.com.
mustafaerdemeczaci.tripod.com

Uzm.Dr.Habibullah Aktaş

Ana Sayfa

Güneş Işığından Korunmada Bazı Antioksidanlar

*** Protective effects of a topical antioxidant mixture containing vitamin C, ferulic acid, and phloretin against ultraviolet-induced photodamage in human skin

Oresajo, Christian1; Stephens, Thomas2; Hino, Peter D3; Law, Robert M4; Yatskayer, Margarita1; Foltis, Peter1; Pillai, Sreekumar1; Pinnell, Sheldon R5

Source: Journal of Cosmetic Dermatology, Volume 7, Number 4, December 2008 , pp. 290-297

***Ultraviolet (UV) irradiation of the skin leads to acute inflammatory reactions, such as erythema, sunburn, and chronic reactions, including premature skin aging and skin cancer. Aim

In this study, the effects of a topical antioxidant mixture consisting of vitamin C, ferulic acid, and phloretin on attenuating the harmful effects of UV irradiation on normal healthy volunteers were studied using biomarkers of skin damage. Subjects/methods

Ten subjects (age, 18-60 years; Fitzpatrick skin types II and III) were randomized and treated with antioxidant product or vehicle control on the lower back for four consecutive days. On day 3, the minimal erythema dose (MED) was determined for each subject at a different site on the back. On day 4, the two test sites received solar-simulated UV irradiation 1-5× MED at 1× MED intervals. On day 5, digital images were taken, and 4-mm punch biopsies were collected from the two 5× MED test sites and a control site from each subject for morphology and immunohistochemical studies. Results

UV irradiation significantly increased the erythema of human skin in a linear manner from 1× to 5× MED. As early as 24 h after exposure to 5× MEDs of UV irradiation, there were significant increases in sunburn cell formation, thymine dimer formation, matrix metalloproteinase-9 expression, and p53 protein expression. All these changes were attenuated by the antioxidant composition. UV irradiation also suppressed the amount of CD1a-expressing Langerhans cells, indicating immunosuppressive effects of a single 5× MED dose of UV irradiation. Pretreatment of skin with the antioxidant composition blocked this effect. Conclusion

This study confirms the protective role of a unique mixture of antioxidants containing vitamin C, ferulic acid, and phloretin on human skin from the harmful effects of UV irradiation. Phloretin, in addition to being a potent antioxidant, may stabilize and increase the skin availability of topically applied vitamin C and ferulic acid. We propose that antioxidant mixture will complement and synergize with sunscreens in providing photoprotection for human skin.

Dar Bant UVB Tedavisi Deri kanserine neden olmuyor

Incidence of skin cancers in 3867 patients treated with narrow- band ultraviolet B phototherapy

Narrow-band ultraviolet B (NB-UVB) phototherapy is a widely used treatment. Psoralen-UVA photochemotherapy (PUVA) increases skin cancer risk and some animal studies have raised the possibility of an increased risk with NB-UVB. The risk of skin cancer in humans following treatment with NB-UVB is unknown. Objectives

This current analysis forms part of an ongoing study ultimately aiming to define the long-term carcinogenic risk of NB-UVB treatment in humans. Methods

Details of all patients receiving NB-UVB treatment until 31/12/2002 in Tayside, Scotland, were accessed from a treatment database and linked to the Scottish Cancer Registry. Indirect standardization was used to compare skin cancer incidence in the study population with age and sex matched cancer registry data for the Tayside population. We also assessed the effect of NB-UVB exposure treatment numbers on the risk of developing skin cancer. Results

Of 4690 records reviewed, 4665 were suitable for analysis with 3886 records linked with the cancer registry and 3867 followed-up for at least 6 months before 31/12/02 (the date at which cancer registration was deemed to be complete). The median number of NB-UVB treatments was 29 with 352 patients receiving ≥ 100 treatments. The study gave 24 753 person-years of follow up. First skin cancers recorded in study patients were 27 basal cell carcinomas (BCC), seven squamous cell carcinomas (SCC) and six melanomas. No association was found between NB-UVB exposure alone (without PUVA) and any skin cancer. For NB-UVB and PUVA treated patients there was an association with BCC, with 27 BCCs found compared with 14·1 expected in the matched population. Conclusion

We found no significant association between NB-UVB treatment and BCC, SCC or melanoma. There was a small increase in BCCs amongst those also treated with PUVA. These reassuring results do not demonstrate the early increase in skin cancers that was found associated with PUVA treatment. However, cautious interpretation is required as the cohort contained relatively few patients who had a high treatment number and because the slow evolution of skin cancers may result in a delayed incidence peak. Ongoing risk assessment is therefore essential.