Investigation of Glypican-4 and -6 by Infrared Spectral Imaging during the Hair Growth Cycle.

The expression of glypicans in different hair follicle (HF) compartments is still poorly understood. Heparan sulfate proteoglycans (HSPGs) distribution in HF is classically investigated by conventional histology, biochemical analysis, and immunohistochemistry. Our previous study proposed a novel approach to assess hair histology and glypican-1 (GPC1) distribution changes in the HF at different phases of the hair growth cycle using infrared spectral imaging (IRSI). We show in the present manuscript for the first time complementary data on the distribution of glypican-4 (GPC4) and glypican-6 (GPC6) in HF at different phases of the hair growth cycle using IR imaging. Findings were supported by Western blot assays focusing on the GPC4 and GPC6 expression in HFs. Like all proteoglycan features, the glypicans are characterized by a core protein to which sulfated and/or unsulfated glycosaminoglycan (GAG) chains are covalently linked. Our study demonstrates the capacity of IRSI to identify the different HF tissue structures and to highlight protein, proteoglycan (PG), GAG, and sulfated GAG distribution in these structures. The comparison between anagen, catagen, and telogen phases shows the qualitative and/or quantitative evolution of GAGs, as supported by Western blot. Thus, in one analysis, IRSI can simultaneously reveal the location of proteins, PGs, GAGs and sulfated GAGs in HFs in a chemical and label-free manner. From a dermatological point of view, IRSI may constitute a promising technique to study alopecia.

Discovering Hair Biomarkers of Alzheimer's Disease Using High Resolution Mass Spectrometry-Based Untargeted Metabolomics.

Hair may be a potential biospecimen to discover biomarkers for Alzheimer's disease (AD) since it reflects the integral metabolic profiles of body burden over several months. Here, we described the AD biomarker discovery in the hair using a high-resolution mass spectrometry (HRMS)-based untargeted metabolomics approach. A total of 24 patients with AD and 24 age- and sex-matched cognitively healthy controls were recruited. The hair samples were collected 0.1-cm away from the scalp and further cut into 3-cm segments. Hair metabolites were extracted by ultrasonication with methanol/phosphate-buffered saline 50/50 (v/v) for 4 h. A total of 25 discriminatory chemicals in hair between the patients with AD and controls were discovered and identified. The AUC value achieved 0.85 (95% CI: 0.72~0.97) in patients with very mild AD compared to healthy controls using a composite panel of the 9 biomarker candidates, indicating high potential for the initiation or promotion phase of AD dementia in the early stage. A metabolic panel combined with the nine metabolites may be used as biomarkers for the early detection of AD. The hair metabolome can be used to reveal metabolic perturbations for biomarker discovery. Investigating perturbations of the metabolites will offer insight into the pathogenesis of AD.

Extraction of Gallic Acid and Ferulic Acid for Application in Hair Supplements.

Food supplements based on antioxidants and vitamins are often prescribed to correct inefficiencies in the human diet and delay diseases such as premature aging and alopecia (temporary or permanent hair loss), given the free radical scavenging activity of these biomolecules. By reducing the concentration of reactive oxygen species (ROS), which promote abnormal hair follicle cycling and morphology, follicle inflammation and oxidative stress are reduced, minimising the effects of these health issues. Gallic acid (GA), which is significantly present in gallnuts and in pomegranate root bark, and ferulic acid (FA), commonly found in brown rice and coffee seeds, are very important antioxidants for the preservation of hair colour, strength and growth. In this work, these two secondary phenolic metabolites were successfully extracted in the Aqueous Two-Phase Systems (ATPS) {ethyl lactate (1) + trisodium citrate (2) + water (3)} and {ethyl lactate (1) + tripotassium citrate (2) + water (3)} at 298.15 K and 0.1 MPa, moving towards the application of these ternary systems in extracting antioxidants from biowaste and their a posteriori processing as food supplements for hair fortification. The studied ATPS provided biocompatible and sustainable media for the extraction of gallic acid and ferulic acid, yielding low mass losses (<3%) and contributing to an eco-friendlier production of therapeutics. The most promising results were obtained for ferulic acid, which attained maximum partition coefficients (K) of 15 ± 5 and (3 ± 2) · 101 and maximum extraction efficiencies (E) of (92.7 ± 0.4)% and (96.7 ± 0.4)% for the longest tie-lines (TLL = 69.68 and 77.66 m%) in {ethyl lactate (1) + trisodium citrate (2) + water (3)} and {ethyl lactate (1) + tripotassium citrate (2) + water (3)}, respectively. Moreover, the effect of pH on the UV-Vis absorbance spectra was studied for all the biomolecules to minimise errors in solute quantification. Both GA and FA were found to be stable at the used extractive conditions.

Ancient lineages of the keratin-associated protein (KRTAP) genes and their co-option in the evolution of the hair follicle.

BLAST searches against the human genome showed that of the 93 keratin-associated proteins (KRTAPs) of Homo sapiens, 53 can be linked by sequence similarity to an H. sapiens metallothionein and 16 others can be linked similarly to occludin, while the remaining KRTAPs can themselves be linked to one or other of those 69 directly-linked proteins. The metallothionein-linked KRTAPs comprise the high-sulphur and ultrahigh-sulphur KRTAPs and are larger than the occludin-linked set, which includes the tyrosine- and glycine-containing KRTAPs. KRTAPs linked to metallothionein appeared in increasing numbers as evolution advanced from the deuterostomia, where KRTAP-like proteins with strong sequence similarity to their mammalian congeners were found in a sea anemone and a starfish. Those linked to occludins arose only with the later-evolved mollusca, where a KRTAP homologous with its mammalian congener was found in snails. The presence of antecedents of the mammalian KRTAPs in a starfish, a sea anemone, snails, fish, amphibia, reptiles and birds, all of them animals that lack hair, suggests that some KRTAPs may have a physiological role beyond that of determining the characteristics of hair fibres. We suggest that homologues of these KRTAPs found in non-hairy animals were co-opted by placodes, formed by the ectodysplasin pathway, to produce the first hair-producing cells, the trichocytes of the hair follicles.

Hair embedding after transperineal prostate biopsy: two case reports.

BACKGROUND: Transperineal prostate biopsy is gradually becoming the standard methodology for diagnosing prostate cancer because of its high accuracy and low risk of infection, but careful preparation is not always highlighted before a transperineal biopsy. we reported two cases of hair embedding during transurethral resection of the prostate following transperineal puncture biopsy with a Bard MC1820 disposable biopsy needle. Histological examination did not find the hair follicle structure required for hair growth. The hair source was suspected to be percutaneously brought in by needle during the biopsya simulated experiment was used to analyze and reconstruct the process of hair embedding in prostate tissue. CONCLUSION: Hair embedding caused by perineal prostate biopsy is a consumable-related adverse event, and skin preparation before a transperineal prostate biopsy is recommended.

Lrig1-expressing epidermal progenitors require SCD1 to maintain the dermal papilla niche.

Niche cells are widely known to regulate stem/progenitor cells in many mammalian tissues. In the hair, dermal papilla niche cells are well accepted to regulate hair stem/progenitor cells. However, how niche cells themselves are maintained is largely unknown. We present evidence implicating hair matrix progenitors and the lipid modifying enzyme, Stearoyl CoA Desaturase 1, in the regulation of the dermal papilla niche during the anagen-catagen transition of the mouse hair cycle. Our data suggest that this takes place via autocrine Wnt signalling and paracrine Hedgehog signalling. To our knowledge, this is the first report demonstrating a potential role for matrix progenitor cells in maintaining the dermal papilla niche.

Associations between chronic stress and hair cortisol in children: A systematic review and meta-analysis.

OBJECTIVES: This review systematically examined the associations between chronic stress and hair cortisol concentration (HCC) in children, and the potential modification effects of type, measurement period and scales of chronic stress, child age and sex, hair length and HCC measurement method, characteristics of study site, and congruence between time periods measured for chronic stress and HCC. METHODS: Pubmed, Wed of Science, and APA PsycINFO were systematically searched for articles examining the association between chronic stress and HCC. RESULTS: Thirteen studies from five countries with 1,455 participants were included in the systematic review and nine studies were included in the meta-analysis. Meta-analysis revealed that chronic stress was associated with HCC (pooled-r = 0.09, 95 % CI: 0.03, 0.16). Stratified analyses revealed that type, measurement time and scales of chronic stress, hair length and measurement method of HCC, and the congruence between time periods measured for chronic stress and HCC modified such correlations. The positive correlations between chronic stress and HCC were significant for studies measuring chronic stress as stressful life events, assessing chronic stress within the past six months, extracting HCC from 1 cm, 3 cm, or 6 cm of hair, measuring HCC by LC-MS/MS, or having congruence between time periods measured for chronic stress and HCC. The potential modifying effects of sex and country developmental status could not be concluded due to the limited number of studies included. CONCLUSIONS: Chronic stress was positively correlated with HCC, varying by characteristics and measurements of chronic stress and HCC. HCC could be a biomarker for chronic stress among children.

Melatonin and the Human Hair Follicle.

BACKGROUND: Melatonin, a pleiotropic hormone, affects the physiological processes including that of the hair follicle. We seek to identify the scientific evidence to support the potential benefits of melatonin in human hair growth. OBJECTIVE: To summarize the evidence on the association between melatonin and hair health, denoted by hair growth. METHODS: A literature review using 3 databases (PubMed, Google Scholar, and Cochrane) identified studies investigating the relationship between melatonin and hair loss (2022). The following search terms were used: (hair OR hair loss OR alopecia OR hair growth OR effluvium OR scalp) and (melatonin). Two independent reviewers screened studies for inclusion criteria, and data collection included demographics, melatonin intervention, study type, and effects on hair. RESULTS: A total of 11 human studies were identified with evidence of melatonin use in subjects with diagnosed alopecia (2,267 patients; 1,140M). Eight of the studies reviewed observed positive outcomes after topical melatonin use in subjects with androgenetic alopecia (AGA). Most studies report improved scalp hair growth (n=8), density (n=4), and hair shaft thickness (n=2) among melatonin users compared with controls. Effective topical melatonin dosage appears to be 0.0033% or 0.1% solution applied once-daily for 90 to 180 days vs 1.5 mg twice-daily oral melatonin supplementation for 180 days. CONCLUSION: There is evidence to support melatonin use to facilitate scalp hair growth, particularly in men with AGA. Further studies should include more patients and investigate the mechanism of action. J Drugs Dermatol. 2023;22(3): doi:10.36849/JDD.6921.

Wavy changes in the whiskers of domestic cats are correlated with feline leukemia virus infection.

BACKGROUND: Feline leukemia virus (FeLV) is a retrovirus with global impact on the health of domestic cats and is usually examined by serology. In our daily clinical practice, we noticed that cats infected with FeLV often possess wavy whiskers (sinus hairs on the face). To investigate the relationship between wavy whiskers (WW) and FeLV infection, the association between the presence or absence of wavy changes in whiskers and serological FeLV infection was examined in a total of 358 cats including 56 cats possessing WW, using the chi-square test. The results of blood tests from 223 cases were subjected to multivariate analysis (logistic analysis). Isolated whiskers were observed under light microscopy, and upper lip tissues (proboscis) were subjected to histopathological and immunohistochemical analyses. RESULTS: The prevalence of WW was significantly correlated with FeLV antigen positivity in the blood. Of 56 cases with WW, 50 (89.3%) were serologically positive for FeLV. The significant association between WW and serological FeLV positivity was also confirmed by multivariate analysis. In WW, narrowing, degeneration, and tearing of the hair medulla were observed. Mild infiltration of mononuclear cells in the tissues, but no degeneration or necrosis, was found. By immunohistochemistry, FeLV antigens (p27, gp70 and p15E) were observed in various epithelial cells including the sinus hair follicular epithelium of the whisker. CONCLUSIONS: The data suggest that the wavy changes in whiskers, a unique and distinctive external sign on a cat's face, were associated with FeLV infection.

[Levels of mercury in hair among pregnant women in Iceland].

INTRODUCTION: To limit exposure to methylmercury several countries have implimented specific advice on fish intake to pregnant women as well a measuring compliance through regular human biomonitoring. Despite fish intake being relatively high in Iceland, human biomonitoring data on mercury is scarce. MATERIALS AND MEHODS: We measured mercury in hair from 120 pregnant women recruited in 2021 from the the Reykjavik Capital area. At recruitment, information on fish intake during the past four months was recorded. Hair mercury concentrations were compared to existing health based guidance values and associatons with fish intake was explored. RESULTS: Mean (standard deviation) mercury concentration in hair was 0.48 µg/g (0.33). All participants had concentrations in hair below 1.8 µg/g, which corresponds to the hair value that the tolerable daily intake set by the European Food Safety Authority is derived from, while 5% had concentrations above 1.1 µg/g, which corresponds to the hair value that the US-EPA reference dose is derived from. Mean mercury concentrations in hair increased in a dose dependent manner (p for trend p<0.001) from 0.25 µg/g among women who consumed fish ≤ 3/month (n=24) and up to 0.80 mg/g among those consuming fish 3-4/ week (n=16). The few (n=3) women who reported to have eaten shark (p<1/month) were all at the higher end of the exposure distribution. CONCLUSION: Our results suggest that exposure is generally below the tolerable daily intake set by EFSA but may in some women exceed the reference dose established by the US-EPA.

Arsenic in drinking water, hair, and prevalence of arsenicosis in Perak, Malaysia.

Arsenic is a carcinogen element that occurs naturally in our environment. Humans can be exposed to arsenic through ingestion, inhalation, and dermal absorption. However, the most significant exposure pathway is via oral ingestion. Therefore, a comparative cross-sectional study was conducted to determine the local arsenic concentration in drinking water and hair. Then, the prevalence of arsenicosis was evaluated to assess the presence of the disease in the community. The study was conducted in two villages, namely Village AG and Village P, in Perak, Malaysia. Socio-demographic data, water consumption patterns, medical history, and signs and symptoms of arsenic poisoning were obtained using questionnaires. In addition, physical examinations by medical doctors were performed to confirm the signs reported by the respondents. A total of 395 drinking water samples and 639 hair samples were collected from both villages. The samples were analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) to determine arsenic concentration. The results showed that 41% of water samples from Village AG contained arsenic concentrations of more than 0.01 mg/L. In contrast, none of the water samples from Village P exceeded this level. Whilst, for hair samples, 85 (13.5%) of total respondents had arsenic levels above 1 µg/g. A total of 18 respondents in Village AG had at least one sign of arsenicosis and hair arsenic levels of more than 1 µg/g. Factors significantly associated with increased arsenic levels in hair were female, increasing age, living in Village AG and smoking. The prevalence of arsenicosis in the exposed village indicates chronic arsenic exposure, and immediate mitigation action needs to be taken to ensure the wellbeing of the residents in the exposed village.

Comparative ultrastructure of the antennae and sensory hairs in six species of crayfish.

Background: Antennae in crayfish are essential for gaining information about the local topography and localising food, chemicals, conspecifics or predator. There are still gaps in the research on the morphology of antennae in decapods compared to other arthropods. Methodology: Biometrical and ultrastructural methods were applied using light and cryo-scanning electron microscopies to study the morphology of antennae in six different crayfish species, including marbled crayfish Procambarus virginalis, Mexican dwarf crayfish Cambarellus patzcuarensis, red swamp crayfish Procambarus clarkii, signal crayfish Pacifastacus leniusculus, common yabby Cherax destructor, and spiny-cheek crayfish Faxonius limosus to find their potential morphological differences. Results: Significant differences in the antenna length, length and width of each segment to carapace length ratios, and the number of segments were found in the six crayfish species. The ultrastructure revealed differences in the distribution of sensory hairs on the antenna and the morphology of the antennal surface. Conclusions: The different morphology of antennae might reflect adaptation to the conditions of their specific habitats. In addition, results showed that a combination of differences in the morphological features and biometrical measurements of antennae could be used for the distinguishment of different studied crayfish species.

Multidimensional Profiling of Human Body Hairs Using Qualitative and Semi-Quantitative Approaches with SR-XRF, ATR-FTIR, DSC, and SEM-EDX.

This study aimed to assess the potential of a multidimensional approach to differentiate body hairs based on their physico-chemical properties and whether body hairs can replace the use of scalp hair in studies linked to forensic and systemic intoxication. This is the first case report controlling for confounding variables to explore the utility of multidimensional profiling of body hair using synchrotron synchrotron microbeam X-ray fluorescence (SR-XRF) for longitudinal and hair morphological region mapping) and benchtop methods, including attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) (complemented with chemometrics analysis), energy dispersive X-ray analysis (EDX) (complemented with heatmap analysis), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) analysis (complemented by descriptive statistics) to profile different body hairs in terms of their elemental, biochemical, thermal, and cuticle properties. This multidimensional approach provided supportive information to emphasize the intricate and rather complex interplay between the organization and levels of elements and biomolecules within the crystalline and amorphous matrix of different body hairs responsible for the differences in physico-chemical properties between body hairs that are predominantly affected by the growth rate, follicle or apocrine gland activity, and external factors such as cosmetic use and exposure to environmental xenobiotics. The data from this study may have important implications for forensic science, toxicology and systemic intoxication, or other studies involving hair as a research matrix.

The potential health risks of short-chain chlorinated paraffin: A mini-review from a toxicological perspective.

Short-chain chlorinated paraffins (SCCPs) are ubiquitously distributed in various environmental matrics due to their wide production and consumption globally in the past and ongoing production and use in some developing countries. SCCPs have been detected in various human samples including serum, milk, placenta, nail, and hair, and internal SCCP levels were found to be positively correlated with biomarkers of some diseases. While the environmental occurrence has been reported in a lot of studies, the toxicity and underlying molecular mechanisms of SCCPs remain largely unknown. The current tolerable daily intakes (TDIs) recommended by the world health organization/international programme on chemical safety (WHO/IPCS, 100 µg/kg bw/d) and the UK Committee on Toxicity (COT, 30 µg/kg bw/d) were obtained based on a no observed adverse effect level (NOAEL) of SCCP from the repeated-dose study (90 d exposure) in rodents performed nearly 40 years ago. Importantly, the health risks assessment of SCCPs in a variety of studies has shown that the estimated daily intakes (EDIs) may approach and even over the established TDI by UK COT. Furthermore, recent studies revealed that lower doses of SCCPs could also result in damage to multiple organs including the liver, kidney, and thyroid. Long-term effects of SCCPs at environmental-related doses are warranted.

The effects of sun exposure on colorant identification of permanently and semi-permanently dyed hair.

During bloating and active decay, human remains begin to deform and warp their physical identity. After the skin and muscles loosen and detach from their skeletal structuration, everything but bones, teeth, and hair will fully disintegrate into the soil that surrounds the body. Nearly half of people in the world dye their hair with a variety of permanent and semi-permanent colorants. Expanding upon this, we hypothesized that confirmatory analysis of hair colorants can be used to facilitate and advance forensic analysis of human remains. A growing body of evidence suggests that hair colorants can be identified directly on hair using surface-enhanced Raman spectroscopy (SERS). In this study, we investigate the extent to which SERS can be used to detect black and blue permanent and semi-permanent dyes on hair exposed to sunlight. Our results showed that although substantial photodegradation of all dyes was observed by week 7, SERS enabled highly accurate detection and identification of hair colorants during all 10 weeks of hair exposure to the sunlight with on average 99.2% accuracy. We also found that SERS could be used to predict fading rates of hair colorants. This information can shed light on the exposure of human remains to the exterior environment.

Characterizing the adult exposome in men and women from the general population: Results from the EHES-LUX study.

Throughout life individuals are exposed to a large array of diverse environmental exposures (exposome). Hair analyses can assess chronic exposure to a large number of chemicals with less intra-variability than urine and blood. This is essential for studies that aim to achieve a global vision of the exposome. We aimed at characterizing the adult exposome by describing 175 environmental exposures and correlation patterns between and within exposure groups. A subsample of participants of the European Health Examination Survey, covering information on exposure to chemical pollutants in hair samples, were included in the present analysis (N = 442). Concentrations of micronutrients, lifestyle, home environment and socioeconomic information completed the exposome description and were obtained through blood analyses and questionnaires. We detected 29 persistent and non-persistent chemical pollutants in more than 70% of hair samples. Compared to women, men had higher concentrations of pesticides, lower concentrations of micronutrients (with the exception of vitamin A), and presented higher alcohol consumption. Across all exposures, a low median absolute correlation was found, 0.05 (5th - 95th centiles = 0.10, 0.20). We observed higher correlations and median correlations within exposure groups than between groups of exposure. The highest median correlation was observed between plasticizers (bisphenol A and S) in both men (0.50) and women (0.31). A 70% and 95% of cumulative variance was explained by 37 and 73 principal components respectively. We found a wide range of chemical exposures in hair samples of men and women. The adult exposome was complex and multidimensional. Future exposome studies should include hair as a matrix for characterizing exposure to multiple environmental chemicals.

Characterizing variability in total mercury hair:blood ratio in the general Canadian population.

BACKGROUND/OBJECTIVES: The body burden of mercury in humans can be measured through hair or blood biomarkers. To compare results from different studies, it is often required to convert mercury in hair to an equivalent level in blood, using a default hair:blood ratio of 250:1 by the World Health Organization (WHO). However, the actual ratio may vary within and between populations. The objectives of this study were to analyze the hair:blood mercury ratio in the general Canadian population, explore factors associated with higher/lower ratios, and determine if the standard ratio of 250:1 is supported. METHODS: The Canadian Health Measures Survey (CHMS) Cycle 5 (2016-2017) measured total mercury (THg) in both hair and blood of 1168 participants 20-59 years of age. We calculated geometric mean (GM) concentrations of THg for this entire sample and subgroups. The subgroups included biological sex, women of childbearing age, race, hair treatments, categories of blood and hair selenium, urinary arsenobetaine/arsenocholine, categories of blood and hair mercury, and food consumption. We calculated a hair:blood ratio for each participant and determined population-level ratios from the GMs of the distributions. Differences by subgroups, and agreement with the WHO ratio of 250:1, were tested. The combined effect of factors on the THg hair:blood ratio was explored using staged regression analysis. RESULTS: For participants with paired hair and blood mercury measurements, the GM of the hair:blood THg ratio was 293 (95%CI:273-316), and significantly >250. In women of childbearing age, the ratio did not differ from 250. The GMs of the ratio were higher (i.e.>300) for second tertile blood selenium (365, 95%CI:307-433), third and fourth quartiles hair mercury (347, 95%CI:308-390 and 376, 95%CI:336-422), and consumers of shellfish (338, 95%CI:308-371). Shellfish consumption was the only statistically significant factor associated with the hair:blood ratio as identified in the regression model. CONCLUSIONS: The mean hair:blood THg ratio among Canadians generally exceeded the default ratio of 250:1. Higher ratios were observed in certain subgroups, such as seafood consumers, and shellfish consumption was the most important variable associated with the ratio. Our results suggest that population-specific hair:blood THg ratios be considered, if possible, when converting mercury levels from hair to blood to better characterize the variation around the conversion.

Polybrominated diphenyl ethers and bromophenols in paired serum, hair, and urine samples of e-waste dismantlers: Insights into hair as an indicator of endogenous exposure.

Polybrominated diphenyl ethers (PBDEs) are important pollutants during dismantling activities of electronic waste (e-waste) in China due to its large production and usage. Bromophenols (BPs), which are a kind of flame retardants and diphenyl ether bond cleavage metabolites of PBDEs, are often neglected in the assessment of human exposure to e-waste. Herein, 22 PBDEs and 19 BPs were determined in paired serum, hair, and urine samples collected from workers and residents of a typical e-waste dismantling site in southern China. Both PBDE and BP congeners were more frequently detected in hair than serum and urine samples. The medians of ΣPBDEs and ΣBPs were 350 and 547 ng/g dw in hair internal (hair-In) of occupational population, respectively, which were significantly higher than non-occupational population. However, a non-significant difference was found in levels of ΣPBDEs and ΣBPs in serum and urine between occupational and non-occupational populations, suggesting that hair analysis could easily differentiate between the exposure intensities of PBDEs and BPs to populations than serum and urine analyses. Moreover, levels of BPs in hair-In were 1-2 orders of magnitude higher than those in hair external (hair-Ex), while a non-significant difference was found in the levels of PBDEs. This result indicated that BPs might have originated from endogenous contribution. Notably, as the predominant congeners, the level of 2,4,6-tribromophenol (2,4,6-TBP) in hair-In was 3-8 times higher than that of BDE-209, while level of 2,4,6-TBP in hair-Ex was 1-3 times lower than that of BDE-209. Furthermore, in vivo experiments performed on Sprague-Dawley rats following a 28-day oral treatment with BDE-209 and 2,4,6-TBP verified that endogenous accumulation of 2,4,6-TBP in hair could be attributed to the metabolism of BDE-209 and exposure to 2,4,6-TBP. In conclusion, compared with PBDEs, biomonitoring phenolic compounds or metabolites with hair could better reflect human endogenous exposure.

Potentially toxic elements in human scalp hair around China's largest polymetallic rare earth ore mining and smelting area.

There is a growing concern about human health of residents living in areas where mining and smelting occur. In order to understand the exposure to the potentially toxic elements (PTEs), we here identify and examine the cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in scalp hair of residents living in the mining area (Bayan Obo, n = 76), smelting area (Baotou, n = 57) and a reference area (Hohhot, n = 61). In total, 194 hair samples were collected from the volunteers (men = 87, women = 107) aged 5-77 years old in the three areas. Comparing median PTEs levels between the young and adults, Ni levels were significantly higher in adults living in the smelting area while Cr was highest in adults from the mining area, no significant difference was found for any of the elements in the reference area. From the linear regression model, no significant relationship between PTEs concentration, log10(PTEs), and age was found. The concentrations of Ni, Cd, and Pb in hair were significantly lower in the reference area when compared to both mining and smelting areas. In addition, Cu was significantly higher in the mining area when compared to the smelting area. Factor analysis (FA) indicated that men and women from the smelting area (Baotou) and mining area (Bayan Obo), respectively, had different underlying communality of log10(PTEs), suggesting different sources of these PTEs. Multiple factor analysis quantilized the importance of gender and location when combined with PTEs levels in human hair. The results of this study indicate that people living in mining and/or smelting areas have significantly higher PTEs (Cu, Ni, Cd, and Pb) hair levels compared to reference areas, which may cause adverse health effects. Remediation should therefore be implemented to improve the health of local residents in the mining and smelting areas.

Vellus hair condition is related to dermal elasticity and facial sagging severity.

BACKGROUND: Sagging of facial skin is a critical factor associated with an aged appearance. However, the mechanism of sagging has not been fully elucidated. The facial skin contains vellus hair (fine hair), but the contribution of vellus hair to skin condition and facial aging has yet to be studied. AIM: We aimed to clarify the influence of vellus hair on the physical properties and sagging severity of facial skin by establishing an evaluation system for vellus hair condition. METHOD: Photographs were taken to assess the vellus hair condition in the cheek area in 30 middle-aged female volunteers. Skin elasticity was measured with a cutometer and sagging severity was evaluated by using previously established photograph-based grading criteria. RESULTS: Facial skin vellus hairs were divided into three types: fine, thick, and normal thickness. Based on this observation, we established a 6-grade photograph-based grading system based on the dominant type of vellus hair in the target area and used it to evaluate vellus hair condition at the cheek. We found that vellus hair condition is significantly positively related to skin elasticity parameters Ua/Uf (representing overall elasticity including creep and creep recovery), Ur/Ue (representing net elasticity without viscoelastic creep), and Ur/Uf (ratio of elastic recovery to total deformation). Further, vellus hair condition was significantly negatively correlated to sagging severity. CONCLUSION: Our results suggest that vellus hair condition positively contributes to the skin's physical properties, and consequently deterioration of the vellus hair condition promotes an aged facial appearance.