Alternatives to Outdoor Daylight Illumination for Photodynamic Therapy—Use of Greenhouses and Artificial Light Sources

Daylight-mediated photodynamic therapy (daylight PDT) is a simple and pain free treatment of actinic keratoses. Weather conditions may not always allow daylight PDT outdoors. We compared the spectrum of five different lamp candidates for indoor “daylight PDT” and investigated their ability to photobleach protoporphyrin IX (PpIX). Furthermore, we measured the amount of PpIX activating daylight available in a glass greenhouse, which can be an alternative when it is uncomfortable for patients to be outdoors. The lamps investigated were: halogen lamps (overhead and slide projector), white light-emitting diode (LED) lamp, red LED panel and lamps used for conventional PDT. Four of the five light sources were able to photobleach PpIX completely. For halogen light and the red LED lamp, 5000 lux could photobleach PpIX whereas 12,000 lux were needed for the white LED lamp. Furthermore, the greenhouse was suitable for daylight PDT since the effect of solar light is lowered only by 25%. In conclusion, we found four of the five light sources and the greenhouse usable for indoor daylight PDT. The greenhouse is beneficial when the weather outside is rainy or windy. Only insignificant ultraviolet B radiation (UVB) radiation passes through the greenhouse glass, so sun protection is not needed

CHEK2*1100delC and Risk of Malignant Melanoma: Danish and German Studies and Meta-Analysis

It is possible that reduced function of DNA repair and cell-cycle control genes increases the individual susceptibility to malignant melanoma. As CHEK2 is a cell-cycle master controller, we tested the hypothesis that heterozygosity for the frameshift alteration CHEK2*1100delC is associated with increased risk of malignant melanoma. First, we performed case–control studies of 1,152 Danish and 752 German individuals with malignant melanoma compared with 9,142 Danish and 3,718 German controls. Second, we performed a meta-analysis of CHEK2*1100delC and malignant melanoma, involving 2,619 cases and 17,481 controls. Third, we examined the risk of malignant melanoma associated with CHEK2*1100delC heterozygosity in an analysis stratified for sun exposure, as well as for subtype and location on the body. The odds ratios for malignant melanoma for CHEK2*1100del heterozygotes compared with those for noncarriers were 2.01 (95% confidence interval (CI), 1.03–3.91) in Danes, 1.42 (95% CI, 0.46–4.31) in Germans, and 1.79 (95% CI, 1.02–3.17) in Danes and Germans combined. In a meta-analysis, the odds ratio of malignant melanoma for CHEK2*1100delC heterozygotes compared with that for noncarriers was 1.81 (95% CI, 1.07–3.05). Stratifications did not alter these results. CHEK2*1100delC heterozygotes have a twofold risk of malignant melanoma compared with noncarriers

Sunscreen use optimized by two consecutive applications.

Sunscreen users are often inadequately protected and become sunburned. This study aimed to investigate how much two consecutive sunscreen applications increased the quantity of sunscreen applied and decreased the skin area left without sunscreen (missed area) compared to a single application. Thirty-one healthy volunteers wearing swimwear were included and applied sunscreen two consecutive times in a laboratory environment. Participants had pictures taken in black light before and after each application. As sunscreens absorb black light, the darkness of the skin increased with increasing amounts of sunscreen applied. We conducted a standard curve establishing a link between change in picture darkness and quantity of sunscreen. The quantity of sunscreen at selected skin sites as well as the percentage of missed area was determined after each application. Participants had missed a median of 20% of their available body surface after a single application. After double application they had missed 9%. The decrease in missed areas was significant for the whole body surface and for each of the body regions separately. The median participant had applied between 13% and 100% more sunscreen at the selected skin sites after double application than after single application. We recommend double application, especially before intense sun exposure

Quantity of sunscreen and picture darkness.

<p>The standard curve between quantity of sunscreen, <i>Q</i>, and change in darkness of pictures taken in black light, <i>D</i>, with the equation: <i>D</i> = 0.379×2^{−0.367·<i>Q</i>}+0.654×2^{−8.051·<i>Q</i>}.</p

Pictures in black light.

<p>Pictures in black light of the back of the legs of a participant before application (a), after single application (b), and after double application (c). Pictures in black light of 6 squares on the lower back of a volunteer with increasing quantities of sunscreen; 0 mg/cm²; 0.25 mg/cm²; 0.5 mg/cm²; 1.0 mg/cm²; 1.5 mg/cm²; and 2.0 mg/cm². Applied quantities are written on the picture (d). Skin covered with sunscreen appears darker than non-covered skin.</p