Feature spectrum extraction of human fingernails based on LCTF multispectral imaging

A multispectral imaging system consisting of liquid crystal tunable filter(LCTF)and charge coupled device(CCD)camera was used to collect the images of fingernail samples at intervals of 10 nm during the spectral range of 450-1 000 nm,and a multispectral image of human fingernails containing 56 bands was obtained.The accurate reflectivity information of fingernails was obtained through referring whiteboard comparative measurement method.Principal component analysis(PCA)and band index method were used to reduce the dimension of the sample images respectively and two feature spaces were obtained.Spectral angle mapping(SAM)was used to classify human fingernails in these two feature spaces.The classification accuracy were above 92.5%and 82.9%respectively.Therefore,the feature space obtained by the PCA can be used as the characteristic spectrum of human fingernails,which provides a reliable basis for the analysis of multispectral spectrum of fingernails and human health assessment in the future.

Understanding the excretion rates of methylmercury and inorganic mercury from human body via hair and fingernails

Effective biomarkers are necessary to better understand the human mercury(Hg) exposure levels. However, mismatched biomarker sampling method causes extra uncertainty in assessing the risk of Hg exposure. To compare the differences between hair and fingernail, and further understand the excretion rates of methylmercury(MeHg) and inorganic mercury(IHg) via hair and fingernails, the total mercury(THg), Me Hg, and IHg concentrations in paired hair and fingernail samples were investigated through paired samples collected from two typical mining areas, Wanshan mercury mine area(WMMA) and Hezhang zinc smelting area(HZSA). The positive correlation in THg, MeHg, and IHg concentrations( p < 0.01) between hair and fingernail samples indicated that those two biomarkers can be corrected in application of assessing human Hg exposure. Compared to fingernails, the hair was suggested to be a more sensitive biomarker as the concentration of THg, MeHg and IHg were 2~4 times higher than those in fingernails. Furthermore, the amounts of THg, MeHg, and IHg excreted via hair were 70~226 times higher than that excreted via fingernails, and the hair plays a more important role than fingernails in the excretion of Hg from human bodies. Present study therefore provides some new insights to better understand the fate of human assimilated Hg.

Liquid Chromatography-Tandem Mass Spectrometry Assay to Detect Ethyl Glucuronide in Human Fingernail: Comparison to Hair and Gender Differences

Over the past decade, the use of hair specimens for the long-term detection of the alcohol biomarker ethyl glucuronide has been increasing in popularity and usage. We evaluated the usefulness of fingernail clippings as a suitable alterna-tive to hair for ethyl glucuronide detection. A liquid chromatography-tandem mass spectrometry method for the detection of ethyl glucuronide in fingernail clippings was fully validated and used to analyze the hair and/or fingernail specimens of 606 college-aged study participants. The limit of detection was 2 pg/mg, the limit of quantitation was 8 pg/mg and the method was linear from 8 to 2000 pg/mg. Intra- and inter-assay imprecision studies at three different concentrations (20, 40, 200 pg/mg) were all within 7.8% and all intra- and inter-assay bias studies at these levels were within 115.1% of target concentration. Ethyl glucuronide levels in fingernail (mean = 29.1 ± 55.6 pg/mg) were higher than ethyl glucuronide levels in hair (mean = 9.48 ± 22.3 pg/mg) and a correlation of the matched pairs was observed (r = 0.552, P < 0.01, n = 529). Evaluating each gender separately revealed that the correlation of male fingernail to male hair was large and significant (r = 0.782, P < 0.01, n = 195) while female hair to female fingernail was small yet sig-nificant (r = 0.249, P < 0.01, n = 334). The study results demonstrated that fingernail may be a suitable alternative to hair for ethyl glucuronide detection and may be the preferred sample type due to the lack of a gender bias.

The Detection of THCA Using 2-Dimensional Gas Chromatography-Tandem Mass Spectrometry in Human Fingernail Clippings: Method Validation and Comparison with Head Hair

Marijuana use as well as abuse is a significant public health and public safety concern in the United States and using hair to identify marijuana users and abusers has been gaining acceptance in a number of venues including workplace, court ordered, and substance abuse treatment monitoring. After the presentation of a fully validated 2-dimensional gas chromatography-tandem mass spectrometry method for the detection of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCA), the chief metabolite of the main psychoactive compound in marijuana, Δ9-tetrahydrocannabinol (THC), we evaluated the usefulness of fingernail clippings as an alternative specimen type to hair by the analysis of a set of 60 matched pairs of head hair and fingernail clippings. The limit of detection was 10 fg/mg, the limit of quantitation was 20 fg/mg, and the assay was linear from 20 fg/mg to 500 fg/mg. The intra- and inter-assay imprecision and bias studies at 4 different concentrations (50, 100, 500, and 1000 fg/mg) were acceptable where all % Target observations were within 16% of their expected concentrations and all %CV calculations were less than 13.5%. THCA was detectable in more fingernail specimens (53.3%) than hair specimens (46.7%) and the mean concentrations in nails were on average 4.9 times higher than in hair (1813 fg/mg and 364 fg/mg, respectively). The THCA concentrations in hair and nail were strongly associated (r = 0.974, P < 0.01, n = 60) and the association was significant. The study demonstrated that fingernail clippings are a suitable alternative specimen type to hair to monitor for marijuana use and abuse.

Ingrowing Nail Correction by Advancing Composite Flap of the Nailbed and Periosteum—A Simple and Effective Technique

Ingrowing toenails are common particularly in young adults. They usually result in a prolonged period of discomfort or pain that is sufficient to interfere with working and social activities. Apart from the toes, ingrowing nails can affect the fingers as well. Surgery is still the mainstay of treatment. A number of techniques have been described in the literature. But in all there is a high recurrence rate and sometimes the cosmetic result is not acceptable. In this article we describe our technique of surgical management of ingrowing nails of the toes and fingers. The technique involves excision of a part of the lateral nail fold and raising a composite flap consisting of the nail bed and the underlying periosteum which is then advanced. 105 cases were operated using this technique with very good postoperative results.

FINGERNAIL GROWTH RATE IN A NORMAL CHINESE POPULATION

Objective To investigate fingernail growth rate (FNGR) role in the physiological or pathological status of the fingernails in normal Chinese population. Methods The FNGR was measured with vernier caliper. The data of 1 595 fingernails from 208 normal Chinese subjects (including 96 men and 112 women; age ranging from 14 to 78 years) were analyzed. Results The average FNGR was (0.104±0.027) mm per day. Higher growth rates were observed in males than in females, in the young individuals than in the old individuals, in summer than in winter, and in the right hand than in the left hand, respectively. The FNGR differed among fingernails and decreased in order of precedence: middle fingernails, index fingernails or ring fingernails, thumb and little fingernails. Conclusion FNGR was significantly associated with age, gender and temperature. Different fingernail grew at an individual speed.

Hydration of Fingernail Investigated by Optical Coherence Tomography

Optical coherence tomography(OCT) is used to investigate the microstructure changes of human fingernail induced by hydration.Images of nail plate are obtained to display the morphology of fingernail and to disclose the keratinization of basal cells of nail plate.Combined with digital vernier caliper,this imaging technology is used to evaluate thicknesses and changes of nail in vitro after immersion with time.OCT images of nails show that the dorsal and ventral layers of nails have similar thicknesses which are much thinner than intermediate layer.The total thickness of fingernail exponentially increases with immersion time,and the saturating phenomenon appears at about 12 min.Three layers show different contributions to the total increase of the thickness of 17.4%.Microstructure changes in vivo are similar to the results in vitro.The changes of optical path length also could be evaluated by this method.OCT is capable of reflecting precise microstructure changes,and it has the potential to provide physician with a modern and objective diagnostic standard for nail inspection(NI) and to monitor disorders in Chinese traditional medicine(CTM) clinical practice and research.