Epidermal photoprotection: comparative study of narrowband ultraviolet B minimal erythema doses with and without stratum corneum stripping in normal and vitiligo skin.

BACKGROUND: Recent accumulating data in the literature have indicated a complex photoprotective role of the epidermis, and the role of melanin as the major epidermal photoprotective mechanism has become debatable. AIM: Comparative assessment of the photoprotective roles played by different epidermal structures and compounds. METHODS: In total, 64 participants, comprising patients with vitiligo (n = 32) and healthy volunteers (n = 32), with skin phototypes (SPTs) II to V, were enrolled in the study. Areas of skin were delineated; for both lesional and nonlesional skin, the stratum corneum (the SC) was stripped, followed 24 h later by exposure to narrowband ultraviolet B (NB-UVB) irradiation, to measure the minimal erythema dose (MED) in normal, stripped normal, vitiliginous and stripped vitiliginous skin models. These MED values were used to assess the photoprotective role of epidermal structures: melanin, viable epidermis (VE) and the SC. RESULTS: In the vitiligo group, the MED values were significantly (P < 0.05) different between the skin models, being highest in normal skin, followed by stripped normal, vitiliginous and stripped vitiliginous skin. A similar significance level was found within each SPT for almost all comparisons. There was also a significant (P < 0.001) positive correlation between MED and SPTs. There were also significant (P < 0.05) differences in MED values calculated for epidermal structures, being highest for VE, followed by melanin and then the SC, and there was a significant (P < 0.05) positive correlation between MED and SPTs. CONCLUSION: Epidermal photoprotection may extend beyond melanin production, involving several factors such as epidermal layer thickness, optical properties and chromophores. Such a role was perceived to be reactive to UV irradiation, and more efficient in those with higher SPTs.

Localized induction of micronuclei in the oral mucosa of xeroderma pigmentosum patients.

Xeroderma pigmentosum (XP) patients are predisposed not only to skin cancers but also to tumors on the tip of the tongue. Although this enhanced risk has been attributed to a defect in the repair of DNA damage induced by ultraviolet rays from sunlight there is a lack of data showing that DNA damage is occurring in vivo at these sites. In order to determine whether a relationship exists between exposure to ultraviolet light and the level of chromosomal breakage occurring in epithelial tissue in XP patients, the exfoliated cell micronucleus test was applied to different sites in the oral cavities of four XP patients: the right and left buccal mucosa, the dorsal tip of the tongue and the palate. Six Egyptian controls were sampled concurrently. Micronucleus (MN) frequencies were higher in XP patients than in controls for all sites except the palate, where technical difficulties were encountered. In addition, an unequal distribution of the frequency of micronucleated cells was found in the different sample sites of the oral cavity in the XP patients, with the greatest elevation in frequencies among cells collected from the dorsal tip of the tongue. In contrast, the frequency of micronucleated cells did not vary significantly in samples from different sites obtained from the controls. These data suggest that the complex interplay of host and environmental factors can affect MN frequencies when this endpoint is used to quantify in vivo genotoxic damage in a tissue.

Serological assessment of acyclovir treatment of herpes genitalis.

Oral acyclovir was given to 60 patients with herpes genitalis--20 experiencing a first attack and 40 with recurrent attacks. All patients were followed up for 1 year. Serial serum samples from the patients as well as from 20 controls were studied to determine the effect of therapy on the immune response to herpes simplex virus (HSV). No toxicity was observed, and very few patients had rather insignificant side effects (e.g., diarrhea). The frequency of recurrence (number of recurrences per year) of genital herpes in acyclovir-treated patients was found significantly lower than in controls. More frequent recurrences were observed in those who had high antibody titer in their early convalescent phase sera than in those without or with a low titer of such antibodies. The antibody titers were reduced in those who received acyclovir as compared with controls. The mean time to seroconversion was longer in the acyclovir-treated group than in controls. Oral acyclovir is thus effective and well tolerated in patients with herpes genitalis. Treatment with acyclovir also diminishes the humoral antibody response to HSV, but it does not prevent recurrence. The effects of acyclovir on the immune response to HSV are discussed.

Cigarette smoking and male reproduction.

The effects of cigarette smoking on male reproduction were studied through measuring the serum estradiol (E2), prolactin (PRL), and total testosterone (T). Smoking men had higher levels of E2 and PRL but normal T compared to nonsmokers. Raised E2 and PRL may be among the mechanisms through which cigarette smoking impairs male reproduction.

PIP: Male cigarette smokers have been found to have a lower proportion of motile sperm than nonsmokers, and some studies have reported an increased proportion of abnormal sperm in smokers. To further assess the effects of cigarette smoking on male reproduction, serum levels of estradiol (E2), prolactin (PRL), and total testosterone (T) were compared in 50 heavy smokers (median 23.5 cigarettes/day) and 35 men who never smoked. The median age was 25.4 years among smokers and 27.4 years among nonsmokers. The differences between these 2 groups of men in terms of E2 and PRL levels were significant. Smokers showed elevated E2 levels (median, 59.8 pcg/ml + or - 1.83) compared with nonsmokers (median, 48.6 pcg/ml + or - 0.9) (p 0.001). The median serum PRL level was 10.11 ng/ml + or - 0.55 in smokers compared with 7.88 ng/ml = or - 0.54 in nonsmokers (p 0.001). The median level of serum T did not differ significantly between smokers (4.53 ng/ml + or - 0.17) and nonsmokers (4.55 ng/ml + or - 0.24). Of interest is the finding that smoking appears to elevate E2 in men, while it lowers E2 in women. Since estrogen is a strong stimulus for PRL secretion, the elevated E2 level in smokers may be the mechanism that produces raised serum PRL as well. The finding of a lack of difference between smokers and nonsmokers in T levels suggests that the steroidogenic function of the testis is not affected by smoking; on the other hand, smoking may affect the free fraction of T.