Erythema action spectrum of topical 8-methoxypsoralen-sensitized skin re-evaluated: implications for routine clinical practice

BACKGROUND

Published methodology used to determine psoralen plus ultraviolet A (PUVA) erythemal action spectrum does not reflect current clinical practice for psoralen sensitization. We re-evaluated the PUVA action spectrum using aqueous 8-methoxypsoralen (8-MOP) 2·6 mg L(-1) as used routinely in current clinical practice.

OBJECTIVES

To determine the UVA erythema action spectrum of topical 8-MOP-sensitized normal skin.

METHODS

Twenty healthy volunteers with skin phototypes I-V were recruited. Forearms were psoralen-sensitized at 37 °C for 10 min. Six UVA irradiations at 10-nm intervals between 325 and 375 nm were randomly allocated to forearm sites and were applied using a 10-nm bandwidth irradiation monochromator. The visual minimal phototoxic dose (MPD) was recorded on each site at 96 h.

RESULTS

Volunteer Boston phototypes were: I, n = 2; II, n = 6; III, n = 6; IV, n = 5 and V, n = 1. The mean MPD (J cm(-2) ) for all subjects at each wavelength was as follows: 325 nm, 0·64 (SD 0·37); 335 nm, 0·80 (SD 0·58); 345 nm, 0·96 (SD 0·55); 355 nm, 1·50 (SD 0·85); 365 nm, 2·19 (SD 0·90); and 375 nm, 2·89 (SD 1·06). Therefore, the relative sensitization at each wavelength (erythemal action spectrum) was: 1, 0·83, 0·67, 0·43, 0·29 and 0·22. There were significant differences between the PUVA erythemal effectiveness at different wavelengths but none between skin types.

CONCLUSIONS

This study has established the erythemal action spectrum for bath/soak PUVA therapy as is currently performed. In all volunteers, the peak sensitivity was at 325 nm. All volunteers showed a similar trend across the wavelengths studied irrespective of skin type. The determination of the action spectrum for PUVA-induced erythema is important as it permits reliable estimates of erythemal efficacy of any UVA source where the emission spectrum of the lamp is known or can be measured.

Epi-illumination diffraction phase microscopy with white light

We demonstrate the first reflection-based epi-illumination diffraction phase microscope with white light (epi-wDPM). The epi-wDPM system combines the off-axis, common-path, and white light approaches, in a reflection geometry enabling sub-nanometer spatial and temporal noise levels, while providing single-shot acquisition for opaque samples. We verified the epi-wDPM results by measuring control samples with known dimensions and comparing them to measurements from other well-established techniques. We imaged gold-coated HeLa cells to illustrate the tradeoffs between epi-wDPM with low and high spatial coherence.

Quantitative phase imaging with partially coherent illumination

In this Letter, we formulate a mathematical model for predicting experimental outcomes in quantitative phase imaging (QPI) when the illumination field is partially spatially coherent. We derive formulae that apply to QPI and discuss expected results for two classes of QPI experiments: common path and traditional interferometry, under varying degrees of spatial coherence. In particular, our results describe the physical relationship between the spatial coherence of the illuminating field and the halo effect, which is well known in phase-contrast microscopy. We performed experiments relevant to this common situation and found that our theory is in excellent agreement with the data. With this new understanding of the effects of spatial coherence, our formulae offer an avenue for removing halo artifacts from phase images.

What is the risk of having a total hip or knee replacement for patients with lupus?

Individuals with systemic lupus erythematosus (SLE) frequently have arthralgia but joint damage leading to surgery is thought to be less common. In addition to inflammatory damage, other reasons like avascular necrosis (AVN), which is often associated with steroid use, excessive alcohol intake and antiphospholipid syndrome (APS), may increase the likelihood of large joint failure. In this study we aimed to determine the likelihood of having a total hip replacement (THR) or total knee replacement (TKR) for individuals with SLE compared to those without lupus, by performing a retrospective matched case control study of all THRs and TKRs that were performed between 1991 and 2011 and recorded in the General Practice Research Database (GPRD). Individuals with inflammatory arthritis due to any other causes were excluded and the results were adjusted for steroid use, alcohol consumption (drinking status) and APS. The results show that patients with lupus who had a THR or TKR were younger than their peers without lupus. In addition, they appeared to have a significantly increased risk of TKR but the increased risk of THR did not remain after adjustment for steroid use, alcohol consumption and APS.

Relationships among muscle dysmorphia characteristics, body image quality of life, and coping in males

OBJECTIVES

The purpose of this study was to examine relationships among bodybuilding dependence, muscle satisfaction, body image-related quality of life and body image-related coping strategies, and test the hypothesis that muscle dysmorphia characteristics may predict quality of life via coping strategies.

DESIGN

Participants (294 males, Mage=20.5 years, SD=3.1) participated in a cross-sectional survey.

METHODS

Participants completed questionnaires assessing muscle satisfaction, bodybuilding dependence, body image-related quality of life and body image-related coping.

RESULTS

Quality of life was correlated positively with muscle satisfaction and bodybuilding dependence but negatively with body image coping (P<0.05). Body image coping was correlated positively with bodybuilding dependence and negatively with muscle satisfaction (P<0.05). Mediation analysis found that bodybuilding dependence and muscle satisfaction predicted quality of life both directly and indirectly via body image coping strategies (as evidenced by the bias corrected and accelerated bootstrapped confidence intervals).

CONCLUSIONS

These results provide preliminary evidence regarding the ways that muscularity concerns might influence body image-related quality of life.