The effects of topically applied glycolic acid and salicylic acid on ultraviolet radiation-induced erythema, DNA damage and sunburn cell formation in human skin.

BACKGROUND: alpha-Hydroxy acids (alphaHAs) are reported to reduce signs of aging in the skin and are widely used cosmetic ingredients. Several studies suggest that alphaHA can increase the sensitivity of skin to ultraviolet radiation. More recently, beta-hydroxy acids (betaHAs), or combinations of alphaHA and betaHA have also been incorporated into antiaging skin care products. Concerns have also arisen about increased sensitivity to ultraviolet radiation following use of skin care products containing beta-HA. OBJECTIVE: To determine whether topical treatment with glycolic acid, a representative alphaHA, or with salicylic acid, a betaHA, modifies the short-term effects of solar simulated radiation (SSR) in human skin. METHODS: Fourteen subjects participated in this study. Three of the four test sites on the mid-back of each subject were treated daily Monday-Friday, for a total of 3.5 weeks, with glycolic acid (10%), salicylic acid (2%), or vehicle (control). The fourth site received no treatment. After the last treatment, each site was exposed to SSR, and shave biopsies from all four sites were obtained. The endpoints evaluated in this study were erythema (assessed visually and instrumentally), DNA damage and sunburn cell formation. RESULTS: Treatment with glycolic acid resulted in increased sensitivity of human skin to SSR, measured as an increase in erythema, DNA damage and sunburn cell formation. Salicylic acid did not produce significant changes in any of these biomarkers. CONCLUSIONS: Short-term topical application of glycolic acid in a cosmetic formulation increased the sensitivity of human skin to SSR, while a comparable treatment with salicylic acid did not.

Acute oral toxicity of colchicine in rats: effects of gender, vehicle matrix and pre-exposure to lipopolysaccharide.

The oral toxicity of a single administration by gavage (10, 20 or 30 mg kg(-1) body weight) of colchicine (COL) was determined in young, mature male and female Sprague-Dawley rats. The effect of COL was evaluated in the presence or absence of additional treatment variables that included vehicle and lipopolysaccharide (LPS) pre-exposure. The vehicle for COL was either Half and Half cream (H & H) or saline, and each group included pretreatment with either saline or a low, minimally toxic dose (83 microg kg(-1) body weight) of LPS. Colchicine toxicity in both male and female age-matched rats was characterized by progressively more severe dose-related clinical signs of toxicity. These included mortality, decreased body weight and feed intake during the first several days after dosing, with recovery thereafter in surviving animals. There were differences in the severity of the toxic response to COL between male and female rats. The most notable sex-related difference was in COL lethality. Female rats were two times more susceptible to the lethal effects of COL than male rats. Saline or H & H delivery vehicles did not result in any apparent qualitative or quantitative differences in COL toxicity. LPS pretreatment significantly potentiated COL lethality in both males and females, although the potentiation in males was greater than in females. LPS pretreatment modestly increased the COL induced anorexic effect in surviving males, but not in surviving female animals. LPS did not appear to modulate either the body weights or clinical signs of COL induced toxicity in surviving males or females.

Vitamin D intake: a global perspective of current status.

Global high prevalence of vitamin D insufficiency and re-emergence of rickets and the growing scientific evidence linking low circulating 25-hydroxyvitamin D to increased risk of osteoporosis, diabetes, cancer, and autoimmune disorders have stimulated recommendations to increase sunlight (UVB) exposure as a source of vitamin D. However, concern over increased risk of melanoma with unprotected UVB exposure has led to the alternative recommendation that sufficient vitamin D should be supplied through dietary sources alone. Here, we examine the adequacy of vitamin D intake worldwide and evaluate the ability of current fortification policies and supplement use practices among various countries to meet this recommendation. It is evident from our review that vitamin D intake is often too low to sustain healthy circulating levels of 25-hydroxyvitamin D in countries without mandatory staple food fortification, such as with milk and margarine. Even in countries that do fortify, vitamin D intakes are low in some groups due to their unique dietary patterns, such as low milk consumption, vegetarian diet, limited use of dietary supplements, or loss of traditional high fish intakes. Our global review indicates that dietary supplement use may contribute 6-47% of the average vitamin D intake in some countries. Recent studies demonstrate safety and efficacy of community-based vitamin D supplementation trials and food staple fortification introduced in countries without fortification policies. Reliance on the world food supply as an alternative to UVB exposure will necessitate greater availability of fortified food staples, dietary supplement use, and/or change in dietary patterns to consume more fish.

Vitamin D fortification in the United States and Canada: current status and data needs.

Most circulating 25-hydroxyvitamin D originates from exposure to sunlight; nevertheless, many factors can impair this process, necessitating periodic reliance on dietary sources to maintain adequate serum concentrations. The US and Canadian populations are largely dependent on fortified foods and dietary supplements to meet these needs, because foods naturally rich in vitamin D are limited. Fluid milk and breakfast cereals are the predominant vehicles for vitamin D in the United States, whereas Canada fortifies fluid milk and margarine. Reports of a high prevalence of hypovitaminosis D and its association with increased risks of chronic diseases have raised concerns regarding the adequacy of current intake levels and the safest and most effective way to increase vitamin D intake in the general population and in vulnerable groups. The usual daily intakes of vitamin D from food alone and from food and supplements combined, as estimated from the US third National Health and Nutrition Examination Survey, 1988-1994, show median values above the adequate intake of 5 microg/d for children 6-11 y of age; however, median intakes are generally below the adequate intake for female subjects > 12 y of age and men > 50 y. In Canada, there are no national survey data for estimation of intake. Cross-sectional studies suggest that current US/Canadian fortification practices are not effective in preventing hypovitaminosis D, particularly among vulnerable populations during the winter, whereas supplement use shows more promise. Recent prospective intervention studies with higher vitamin D concentrations provided evidence of safety and efficacy for fortification of specific foods and use of supplements.

Topical glycolic acid enhances photodamage by ultraviolet light.

BACKGROUND: Alpha-hydroxy acids (AHAs) are widely used as ingredients in cosmetics. Several studies suggest that AHAs can increase the sensitivity of skin to ultraviolet (UV) light. PURPOSE: This study was performed in order to determine whether short-term dermal treatment with glycolic acid, a representative AHA, can enhance the damaging effects of UV light. The duration of the effect of AHAs on the sensitivity of skin to UV light was also examined. METHODS: The backs of 29 Caucasian subjects were treated, once daily, 6 days per week with either 10% glycolic acid (pH 3.5) or placebo in a randomized double-blinded study. At the end of 4 weeks, sites within each treated area were exposed to 1.5 MED of UV light, determined on previously untreated skin. Specimens were obtained for enumeration of sunburn cells (SBCs) in the first group of subjects (n = 16), whereas cyclobutyl pyrimidine dimers (CPDs) in DNA were determined in the second group (n = 13). The minimal erythema dose (MED) in each site was also determined in the first group of subjects. Sunburn cells and MEDs were re-evaluated in the first group 1 week after discontinuing AHA applications. RESULTS: Glycolic acid caused enhanced sensitivity to UV light measured as increased SBC induction and lowered MEDs. Cyclobutyl pyrimidine dimers were elevated but not to a statistically significant level. No differences in SBCs or MEDs were evident after a week of discontinued treatments. CONCLUSION: Short-term application of 10% glycolic acid sensitizes the skin to the damaging effects of UV light. This photosensitivity is reversed within a week of terminating treatments.

Evaluation and interlaboratory validation of a selective agar for phosphatidylinositol-specific phospholipase C activity using a chromogenic substrate to detect Listeria monocytogenes from foods.

Phosphatidylinositol-specific phospholipase C (PI-PLC) activity is a potential virulence factor and is exhibited only by the Listeria species Listeria monocytogenes and Listeria ivanovii. A chromogenic substrate for the direct detection of PI-PLC activity is available in a new medium (BCM L. monocytogenes plating agar). The use of a chromogenic substrate offers a mechanism with which to directly screen for L. monocytogenes and L. ivanovii other than the esculin used in Oxford (OXF) and Palcam (PAL) agars, which screen for all Listeria species. The specificity levels of BCM plating agar and of BCM confirmation and rhamnose agars were evaluated with 107 Listeria and 10 Bacillus species isolates. In addition, BCM L. monocytogenes plating agar was compared with standard Listeria selective agars (OXF and PAL agars) with regard to the recovery of L. monocytogenes from 2,000 food and environmental samples obtained from eight participating laboratories. A Listeria species was isolated from at least one of the agars in 209 analyses, and L. monocytogenes was isolated in 135 of these analyses. In 27 of the analyses in which L. monocytogenes was isolated, one or more of the selective differential agars used failed to isolate L. monocytogenes, and therefore the results of these analyses were discrepant. Relative to a reference method involving the use of all three agars (OXF, PAL, and BCM agars), the OXF-BCM, PAL-BCM, and OXF-PAL combinations had sensitivities of 99.3, 99.2, and 90.2%, respectively. In statistical analyses of the different combinations of agars, the OXF-BCM and BCM-PAL combinations were found to be superior to the OXF-PAL combination for the detection of L. monocytogenes.