Inter- and Intra-physician variation in quantifying actinic keratosis skin photodamage

We investigated the variations in physician evaluation of skin photodamage based on a published photodamage scale. Of interest is the utility of a 10-level scale ranging from none and mild photodamage to actinic keratosis (AK). The dorsal forearms of 55 adult subjects with various amounts of photodamage were considered. Each forearm was independently evaluated by 15 board-certified dermatologists according to the Global Assessment Severity Scale ranging from 0 (less severe) to 9 (the most progressed stage of skin damage). Dermatologists rated the levels of photodamage based upon the photographs in blinded fashion. Results show substantial disagreement amongst the dermatologists on the severity of photodamage. Our results indicate that ratings could be more consistent if using a scale of less levels (5-levels or 3-levels). Ultimately, clinicians can use this knowledge to provide better interpretation of inter-rater evaluations and provide more reliable assessment and frequent monitoring of high-risk populations.

Quantifying skin photodamage with spatial frequency domain imaging: statistical results

We investigated the change in optical properties and vascular parameters to characterize skin tissue from mild photodamage to actinic keratosis (AK) with comparison to a published photodamage scale. Multi-wavelength spatial frequency domain imaging (SFDI) measurements were performed on the dorsal forearms of 55 adult subjects with various amounts of photodamage. Dermatologists rated the levels of photodamage based upon the photographs in blinded fashion to allow comparison with SFDI data. For characterization of statistical data, we used artificial neural networks. Our results indicate that optical and vascular parameters can be used to quantify photodamage and can discriminate between the stages as low, medium, and high grades, with the best performance of ∼70%, ∼76% and 80% for characterization of low- medium- and high-grade lesions, respectively. Ultimately, clinicians can use this noninvasive approach for risk assessment and frequent monitoring of high-risk populations.

Augmentation of chemotherapy-induced cytokine production by expression of the platelet-activating factor receptor in a human epithelial carcinoma cell line

In addition to their known cytotoxic effects, chemotherapeutic agents can trigger cytokine production in tumor cells. Moreover, many chemotherapeutic agents are potent pro-oxidative stressors. Although the lipid mediator platelet-activating factor (PAF) is synthesized in response to oxidative stress, and many epidermal carcinomas express PAF receptors (PAF-R) linked to cytokine production, it is not known whether PAF is involved in chemotherapeutic agent-induced cytokine production. These studies examined the role of the PAF system in chemotherapy-mediated cytokine production using a model system created by retroviral-mediated transduction of the PAF-R-negative human epidermal carcinoma cell line KB with the human PAF-R. The presence of the PAF-R in KB cells resulted in augmentation of the production of cytokines IL-8 and TNF-alpha induced by the chemotherapeutic agents etoposide and mitomycin C. These effects were specific for the PAF-R, as expression of the G protein-coupled receptor for fMLP did not affect chemotherapeutic agent-induced cytokine production. Moreover, ablation of the native PAF-R in the epithelial cell line HaCaT using an inducible antisense PAF-R strategy inhibited etoposide-induced cytokine production. Oxidative stress and the transcription factor NF-kappaB were found to be involved in this augmentative effect, because it was mimicked by the oxidant tert-butyl-hydroperoxide, which was blocked both by antioxidants and by inhibition of the NFkappaB pathway using a super-repressor IkappaBM mutant. These studies provide evidence for a novel pathway by which the epidermal PAF-R can augment chemotherapy-induced cytokine production through an NF-kappaB-dependent process.