Determination of Keratin Protein in a Tape-stripped Skin Sample from Jet Fuel Exposed Skin

Abstract

Chemical contaminants or their metabolites may bind to and react with keratin proteins in the stratum corneum of the skin. Here, we present a tape-stripping method for the removal and quantification of keratin from the stratum corneum for normalization of extracted concentrations of naphthalene (as a marker for jet fuel exposure) from 12 human volunteers before and after exposure to jet fuel (JP-8). Due to the potential for removal of variable amounts of squamous tissue from each tape-strip sample, keratin was extracted and quantified using a modified Bradford method. Confirmation of the extraction of keratin was verified by western blotting using a monoclonal mouse anti-human cytokeratin antibody. Naphthalene was quantified in the sequential tape strips collected from the skin between 10 and 25 min after a single dose of JP-8 was initially applied. The penetration of jet fuel into the stratum corneum was demonstrated by the fact that the average mass of naphthalene recovered by a tape strip decreased with increased exposure time and subsequent tape strips and that the evaporation of naphthalene was observed to be negligible. There were no significant differences in the amount of keratin or naphthalene removed by tape strips between males and females, between age groups, races or degrees of skin pigmentation. We conclude that (i) the amount of keratin removed with tape strips was not affected by up to a 25 min exposure to JP-8 and (ii) there was a substantial decrease in the amount of keratin removed with consecutive tape strips from the same site, thus, adjusting the amount of naphthalene by the amount of keratin measured in a tape-strip sample should improve the interpretation of the amount of this analyte using this sampling approach. Although we found that normalization of the naphthalene to the amount of keratin in the tape-strip samples did not affect the ability of this method to quantify the dermal exposure to JP-8 under these laboratory conditions, the actual concentration of naphthalene (as a marker for JP-8 exposure) per unit of keratin in a tape-strip sample can be determined using this method and may prove to be required when measuring occupational exposures under field conditions.

Proteomics as a new tool to study fingermark ageing in forensics

“…In contrast to these studies, Cathepsin-D (CATD) could not be identified from our data. The recorded proteomic profile is in line with that observed from the skin surface 18 , 19 , with cytokeratins as dominant protein species. These components make up approximately 35% of the fingermark proteome, whilst the remainder is accounted for by an array of antibiotic proteins as well as secreted blood proteins 22 – 26 .…”

Dermal Exposure to Jet Fuel JP-8 Significantly Contributes to the Production of Urinary Naphthols in Fuel-Cell Maintenance Workers

“…For each worker, body regions sampled included three of the following body parts: forehead, neck, shoulders, arms, hands, legs, knees, feet, and buttocks. Samples were analyzed by gas chromatography–mass spectrometry (GC-MS) (Chao and Nylander-French 2004). The amount of naphthalene removed with the three successive tape-strip samples was adjusted for the surface area of the particular region sampled in order to estimate the regional dermal exposure to naphthalene.…”

“…In this study, we examined the contributions of dermal and inhalation exposure to naphthalene, as a marker for JP-8 exposure (Chao et al 2005; Chao and Nylander-French 2004; Egeghy et al 2003; Serdar et al 2003, 2004), to the levels of urinary 1-naphthol and 2-naphthol in U.S. Air Force (USAF) fuel-cell maintenance workers. We demonstrate, using multiple linear regression analyses, that both dermal and inhalation exposure to JP-8 significantly contribute to urinary 1-naphthol and 2-naphthol levels.…”

Thalidomide Accelerates the Degradation of Extracellular Matrix in Rat Hepatic Cirrhosis via Down-Regulation of Transforming Growth Factor-β1

“…Protein concentration was determined using the Bradford method with bull serum albumin as standard. 23 Proteins (30 µg) from each samples were loaded on a 12% sodium dodecyl sulfonate-polyacrylamide gel and transferred to a nitrocellulose membrane at 80 mA for 2 h in a water-cooled transfer apparatus. The membrane was pre-incubated in blocking buffer [Tris-buffered saline (TBS) containing Tween and 5% non-fat dried milk] for 2 h at room temperature and then probed with a primary antibody (1:200 diluted in blocking buffer) overnight at 4℃.…”