Predictive Model of Nail Consistency Using Scanning Electron Microscopy with Energy-Dispersive X-Ray

Ultrasound clinical references of the healthy toenail unit

The toenail unit, commonly called the nail, is one of the most frequently examined and treated structures in clinical podiatry. Ultrasound is a standard clinical technique because it is a noninvasive, painless, and rapid diagnostic tool. The main objective of this study was to obtain morphometric data of the healthy toenail unit by ultrasound for clinical application. The nails of 76 participants (152 hallux nails; 38 men, 38 women, average age 26.83 ± 12.20) were examined using a VINNO E35 ultrasound system and an X6-16L linear probe with a frequency of 18 MHz. Five ultrasound measures of the healthy toenail unit were obtained, of which only the distance from the center of the distal phalange to the nail plate varied with age, sex, weight, and foot (p-values ≤ 0.050). The other four parameters were less influenced by the variables analyzed, except sex, which influenced nearly all (p-values ≤ 0.050). In one of these variables, indications of significance were observed (p-values = 0.060), with greater distances in the men than in the women, except for nail plate curvature, which showed a higher value. The other variables studied did not influence the parameters analyzed. High-frequency ultrasound can be used to examine the healthy toenail unit and define anthropometric reference measurements that can be used for more accurate and comparative diagnosis.

Trace Element Distribution and Arsenic Speciation in Toenails as Affected by External Contamination and Evaluation of a Cleaning Protocol

Trace element concentrations in toenail clippings have increasingly been used to measure trace element exposure in epidemeological research. Conventional methods such as inductively coupled plasma mass spectrometry (ICP-MS) and high-performance liquid chromatography ICP-MS (HPLC-ICP-MS) are commonly used to measure trace elements and their speciation in toenails. However, the impact of the removal of external contamination on trace element quantification has not been thoroughly studied. In this work, the microdistribution of trace elements (As, Ca, Co, Cu, Fe, K, Mn, Ni, Rb, S, Sr, Ti, and Zn) in dirty and washed toenails and the speciation of As in situ in toenails were investigated using synchrotron X-ray fluorescence microscopy (XFM) and laterally resolved X-ray absorption near edge spectroscopy (XANES). XFM showed different distribution patterns for each trace element, consistent with their binding properties and nail structure. External (terrestrial) contamination was identified and distinguished from the endogenous accumulation of trace elements in toenails─contaminated areas were characterized by the co-occurrence of Co, Fe, and Mn with elements such as Ti and Rb (i.e., indicators of terrestrial contamination). The XANES spectra showed the presence of one As species in washed toenails, corresponding to As bound to sulfhydryl groups. In dirty specimens, a mixed speciation was found in localized areas, containing AsIII-S species and AsV species. ArsenicV is thought to be associated with surface contamination and exogenous As. These findings provide new insights into the speciation of arsenic in toenails, the microdistribution of trace elements, and the effectiveness of a cleaning protocol in removing external contamination.