Azo Pigment and a Basal Cell Carcinoma at the Thumb

Basal cell carcinoma is the most common malignant neoplasm of the skin, whereas the localization at the nail unit is very rare. We report the case of a 58-year-old patient with a periungual basal cell carcinoma at the thumb. The specific feature of the reported case is the frequent exposure to fishing baits that the patient had stained with an unknown colorant. The use of chromatography, mass spectrometry and infrared spectroscopy revealed the colorant as the azo pigment Solvent Red 8. Solvent Red 8 is a widespread synthetic azo pigment that is applied to stain consumer products. Compounds such as Solvent Red 8 can be cleaved to carcinogenic amines under, for example, light exposure, in particular after incorporation into the human body. As a result of the frequent skin contact to this azo pigment, this hazard compound might have induced the basal cell carcinoma in our patient

Interplay of phosphate and carbonate ions with flavin photosensitizers in photodynamic inactivation of bacteria

Photodynamic inactivation (PDI) of pathogenic bacteria is a promising technology in different applications. Thereby, a photosensitizer (PS) absorbs visible light and transfers the energy to oxygen yielding reactive oxygen species (ROS). The produced ROS are then capable of killing microorganisms via oxidative damage of cellular constituents. Among other PS, some flavins are capable of producing ROS and cationic flavins are already successfully applied in PDI. When PDI is used for example on tap water, PS like flavins will encounter various ions and other small organic molecules which might hamper the efficacy of PDI. Thus, the impact of carbonate and phosphate ions on PDI using two different cationic flavins (FLASH-02a, FLASH-06a) was investigated using Staphylococcus aureus and Pseudomonas aeruginosa as model organisms. Both were inactivated in vitro at a low light exposure of 0.72 J cm-2. Upon irradiation, FLASH-02a reacts to single substances in the presence of carbonate or phosphate, whereas the photochemical reaction for FLASH-06a was more unspecific. DPBF-assays indicated that carbonate and phosphate ions decreased the generation of singlet oxygen of both flavins. Both microorganisms could be easily inactivated by at least one PS with up to 6 log10 steps of cell counts in low ion concentrations. Using the constant radiation exposure of 0.72 J cm-2, the inactivation efficacy decreased somewhat at medium ion concentrations but reached almost zero for high ion concentrations. Depending on the application of PDI, the presence of carbonate and phosphate ions is unavoidable. Only upon light irradiation such ions may attack the PS molecule and reduce the efficacy of PDI. Our results indicate concentrations for carbonate and phosphate, in which PDI can still lead to efficient reduction of bacterial cells when using flavin based PS

Concentration of single PAH in skin and lymph nodes compared to tattoo inks.

<p>*mean PAH values recently detected in commercially available black tattoo ink suspensions <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092787#pone.0092787-Regensburger1" target="_blank">[16]</a>.</p><p>**taken from the fact sheet of the JRC, Polycyclic Aromatic Hydrocarbons.</p><p>***below detection limit.</p><p>The bold PAH have been proven to be genotoxic in vitro and in vivo according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092787#pone.0092787-Benford1" target="_blank">[3]</a>.</p

Histology of skin (top) and from the corresponding lymph node (bottom).

<p>The specimens were embedded in paraffin and, after hematoxylin-eosine (H&E) staining, imaged with a Zeiss Axiostar Plus microscope (10 fold optical magnification). The images show black tattoo particles, which are located inside the dermis or lymph node along with various PAH species as detected by extraction and chemical analysis together with adsorbed hazardous PAH.</p

Specimen of black tattooed human skin (top) and one of the corresponding regional lymph node (center), which was cutted into two pieces.

<p>Transmission electron microscopy shows the shape and size of black tattoo particles, which consist of Carbon Black nanoparticles (bottom).</p

HPLC chromatogramis displayed of all 21 PAH (A), which could be detected at the same time.

<p>HPLC chromatogramsare displayed for a skin sample (B), and for a lymph node sample (C).</p

Recovery of phenol (1) and PAH (2–21) from digested human skin using a combination of vortex and ultrasonic extraction in a 2∶1 benzene/acetone solution and keeper without (white) and loaded with (black) Carbon Black particles.

<p>Recovery ranges from 96–99% for both, without and with adding Carbon Black particles whereby the mean RSD (n = 3) did not exceed 3%.</p

Total Concentration of PAH in skin and lymph node specimens.

<p>*below detection limit.</p

Health risks of tattoo colors

The number of tattooed individuals has increased significantly, especially among youth. In the United States ∼24% of the population is tattooed [1], whereas in Europe it is ∼10% [2]. Cosmetic tattoos (permanent make up) to mimic eye, lip or eyebrow-liner, have also become increasingly popular [3]. Tattoos or permanent make-up are simply performed by injection of colorants into the skin using solid needles. Injury of the skin and the application of unregulated colorants cause health problems in humans [4]. A survey is being performed by the Department of Dermatology of the University of Regensburg in order to elucidate the frequency of medical problems with tattoos [5], in particular after laser treatment [6]