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Human Nail (human + nail)
Selected AbstractsIn vitro human nail penetration and kinetics of panthenolINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 4 2007X. Hui Synopsis The in vitro absorption of panthenol into and through the human nail was examined in this study. Panthenol, the alcohol form of pantothenic acid (vitamin B5), is believed to act as a humectant and improve the flexibility and strength of nails. A liquid nail treatment formulated with panthenol (2%) was compared to a solution of panthenol (2%) in water. Fingernail specimens were dosed daily for 7 days with either the nail treatment (non-lacquer film forming) formulation or aqueous solution with sampling performed every 24 h. Panthenol concentrations were determined in the dorsal surface, interior (by drilling and removal) and in the supporting bed under the human nail. Panthenol levels in the dorsal nail (R2 = 0.87; P < 0.001), nail interior (R2 = 0.94; P < 0.001) and nail supporting bed (R2 = 0.79; P < 0.003) showed a significant linear increase with each day of dosing. Significantly more panthenol was delivered into the interior nail and supporting bed by a nail treatment formulation than from an aqueous solution. The film acts not only as a reservoir of panthenol, but also acts to increase the hydration of the nail and the thermodynamic activity of panthenol as well, thereby enhancing diffusion. [source] Investigation of nail permeation enhancement by chemical modification using water as a probeJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 2 2002Gouri G. Malhotra Abstract Our objective was to screen molecules that could interact with keratin in the human nail and thereby improve the topical penetration of actives into and through the nail plate. We used specialized Franz-type diffusion cells for our permeation experiments and water as a marker molecule. Aqueous/hydroalcoholic gels containing the enhancers were spiked with tritiated water and compared with a control (without enhancer). We computed the normalized water flux (defined as a product of flux and nail thickness) for each gel. We defined an enhancement factor for water as the ratio of the normalized water flux from a gel containing enhancer to that of the control. Our results indicate that the chemical structure of the modifier is most important in determining its ability to enhance penetration. The best enhancement effect was obtained using N-(2-mercaptopropionyl) glycine, a mercaptan derivative of an amino acid, in combination with urea. The concentration of each chemical modifier was linearly related to normalized water flux and mercaptan levels were more important that urea levels in penetration enhancement. Barrier integrity of nails was compromised after treatment with effective chemical modifiers. Thus, we have developed a suitable technique to screen nail penetration enhancers using water as a probe. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:312,323, 2002 [source] Detection of explosives on human nail using confocal Raman microscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 2 2009Esam M. A. Ali Abstract Trace amounts of explosives were detected on human nail using confocal Raman microscopy. Contamination of the nail can result from the manual handling, packaging or transportation of explosive substances. Raman spectra were obtained from pentaerythritol tetranitrate (PETN), trinitrotoluene (TNT), ammonium nitrate and hexamethylenetetramine (HMTA) particles on the surface of the nail with dimensions in the range 5,10 µm. An added difficulty in an analytical procedure is the presence of a nail varnish coating that has been applied, which traps the particulate matter between the coating and nail. Using confocal Raman microscopy, interference-free spectra could be acquired from particles of explosives visually masked by the nail varnish. Spectra of the explosives could be readily obtained in situ within 90 s without alteration of the evidential material. Acquisition of a Raman point map of a PETN particle under the nail varnish coating is also reported. Copyright © 2008 John Wiley & Sons, Ltd. [source] Lyonization pattern of normal human nailsGENES TO CELLS, Issue 5 2008Mariko Okada To examine the X-inactivation patterns of normal human nails, we performed the human androgen receptor gene assay of DNA samples extracted separately from each finger and toe nail plates of nine female volunteers. The X-inactivation pattern of each nail was unique and constant for at least 2 years. The frequency of nails with one of the two X-chromosomes exclusively inactivated was 25.9%. In the nails composed of two types of cells with either one X-chromosome inactivated, the two cell types were distributed in patchy mosaics. These findings suggest that the composition of precursor cells of each nail is maintained at each site at least through several cycles of regeneration time, and that the nail plate has a longitudinal band pattern, each band consisting of cells with only one of the two X-chromosomes inactivated. Using the frequency of nails with one of two X-chromosomes exclusively inactivated, we estimated the number of progenitor cells that gave rise to the nail plate during development to be about 3, under the assumption that the process follows the binominal distribution model. A strong correlation observed among the big, index and little fingers, and among the corresponding toes suggests an interesting interpretation concerning their morphogenetic process. 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