Big toenail and hair samples as biomarkers for fluoride exposure - a pilot study.

BACKGROUND: Biomarkers can aid in detecting and preventing clinical disease through the recognition of change in biological samples. The objective of this case-control study was to further the knowledge on the use of big toenail and hair samples as biomarkers for fluoride exposure. METHODS: A total of 48 participants from an endemic (IC) and a non-endemic (SC) fluorosis region were included. Big toenail and hair samples were collected from each participant and the fluoride concentration was determined. The results of 42 participants were reported: 21 participants (11 males and 10 females, mean age 15.66 + 2.61 years) from IC and 21 participants (11 males and 10 females, mean age 15.06 + 0.79 years) from SC. RESULTS: The mean fluoride concentration of big toenail (2.34 ± 0.26 mg/kg) and hair (0.24 ± 0.04 mg/kg) in the endemic region was significantly higher than the mean fluoride concentration of big toenail (0.98 ± 0.08 mg/kg) and hair (0.14 ± 0.02 mg/kg) in the non-endemic region (p < 0.001 and p = 0.004, respectively). The Receiver Operating Characteristic (ROC) analysis showed that the Area Under the Curve (AUC) value was 0.889 for big toenail (p < 0.001) and 0.762 for hair (p = 0.004) samples. The fluoride assay for big toenails exhibits greater observed accuracy than does the fluoride assay for hair. CONCLUSION: Nail and hair samples can serve as biomarkers to detect biological fluoride exposure according to the data of this pilot study. Nevertheless, hair is less sensitive and specific as a biomarker when AUC values of big toenail and hair samples were compared.

The Observation of the Vein Distribution of a Partial Toe-Transfer Flaps with a Short Vascular Pedicle.

BACKGROUND: When performing partial toe-transfer flaps with a short vascular pedicle, as the flap becomes smaller, the likelihood of securing veins in the flap decreases. The purpose of this study was to clarify how frequently the partial toe-transfer flap with a short pedicle (free vascularized half-big toenail flap) contains veins and elucidate how frequently we can secure the veins with an artery via the first web space approach alone, using the Genial Viewer (a near-infrared light transmission imaging device). METHODS: We observed the dorsal vein images of the bilateral big toes of 250 volunteers (male, n = 125; female, n = 125) using the device. We counted the total number of dorsal veins in the big toe, the veins that crossed the margin of the region equivalent to the half-big toenail flap, and the veins that branched off from the fibular side of the flap area. An unpaired Student's t-test was used for the statistical analyses. RESULTS: All of the dorsal big toes contained veins. The mean number of the veins was 2.3 (range, 1-4). Branched-off veins were observed in the area equivalent to the half-big toenail flap in 496 (99.2%) of the big toes, and the mean number of veins was 1.9 (range, 0-4). In four cases, the region contained no veins (unilaterally). Branched-off veins were observed in the first web space in 440 (88.0%) of the big toes, and the mean number of veins was 0.9 (range, 0-2). CONCLUSIONS: The present study indicated high consistency of the veins in partial toe-transfer flaps with a short vascular pedicle and the high possibility of harvesting a flap with only exposing the first web space. In addition, in most cases, the flap will include one or, at most, two veins in the first web space.