Quantitative Analysis of Hair Luster in a Novel Ultraviolet-Irradiated Mouse Model.

Hair luster is a key attribute of healthy hair and a crucial aspect of cosmetic appeal, reflecting the overall health and vitality of hair. Despite its significance, the advancement of therapeutic strategies for hair luster enhancement have been limited due to the absence of an effective experimental model. This study aimed to establish a novel animal model to assess hair gloss, employing ultraviolet (UV) irradiation on C57BL/6 mice. Specifically, UVB irradiation was meticulously applied to the shaved skin of these mice, simulating conditions that typically lead to hair luster loss in humans. The regrowth and characteristics of the hair were evaluated using a dual approach: an Investigator's Global Assessment (IGA) scale for subjective assessment and an image-based pixel-count method for objective quantification. These methods provided a comprehensive understanding of the changes in hair quality post-irradiation. To explore the potential reversibility of hair luster changes, oral minoxidil was administered, a treatment known for its effects on hair growth and texture. Further, to gain insights into the underlying biological mechanisms, bulk RNA transcriptomic analysis of skin tissue was conducted. This analysis revealed significant alterations in the expression of keratin-associated protein (KRTAP) genes, suggesting modifications in hair keratin crosslinking due to UV exposure. These changes are crucial in understanding the molecular dynamics affecting hair luster. The development of this new mouse model is a significant advancement in hair care research. It not only facilitates the evaluation of hair luster in a controlled setting but also opens avenues for the research and development of innovative therapeutic strategies. This model holds promise for the formulation of more effective hair care products and treatments, potentially revolutionizing the approach towards managing and enhancing hair luster.

Preparation and in vitro evaluation of protective effects of Silibinin-loaded polymeric micelles on human hair against UV-B radiation.

BACKGROUND: The purpose of this study was to investigate the protective effect of Silibinin-loaded polymeric micelles from human hair against UV-B radiation. METHODS: Eight formulations with different concentrations of Silibinin, Pluronic F-127, and Labrasol-Labrafil were made by a solvent evaporation method, and the selected formulation was chosen by examining their properties like particle size and loading efficiency. Six groups of human hair, including a group that received the selected formulation, were exposed to UV-B radiation and by calculating its factors such as peak-to-valley roughness, RMS roughness, FTIR, and the amount of protein loss, the protective effect of the selected formulation was judged. RESULTS: According to the results, the loading efficiency and particle size of the selected formulation were 45.34% and 43.19 nm. The Silibinin release profile had two parts, fast and slow, which were suitable for creating a drug depot on hair. Its zeta potential also confirmed the minimum electrostatic interference between the formulation and hair surface. The zeta potential of selected formulation was -5.9 mv. Examination of AFM images showed that the selected formulation was able to prevent the increase in peak-to-valley roughness and RMS roughness caused by UV-B radiation. RMS roughness after 600 h of UV radiation in Groups 5 and 6 was significantly lower than the negative control group and the amount of this factor did not differ significantly between 0 and 600, so it can be concluded that the selected formulation containing Silibinin and the positive control group was able to prevent the increase of RMS roughness and hair destruction. In other hands, the two positive control groups and the selected formulation containing Silibinin were able to effectively reduce hair protein loss. CONCLUSION: Silibinin-loaded polymeric micelles were able to effectively protect hair from structural and chemical changes caused by UV-B radiation.

Carbon Dioxide Fractional Laser Treatment Induces Lgr5+ Stem Cell Activation and Hair Regrowth Through the Canonical Wnt/ß-Catenin Pathway.

BACKGROUND: Different types of alopecia have negative impacts on patients. Recently, some kinds of laser or light therapies have been reported to effectively alleviate hair loss. Carbon dioxide fractional laser (CO2FL) treatment is one of the most effective laser treatments, but its beneficial effects and exact mechanism in hair regrowth have not been reported in detail. The purpose of this study was to investigate the effect and molecular mechanism further. METHODS: C57 and Lgr5-Cre: Rosa-mTmG mouse models of hair regrowth were established by CO2FL treatment, and the parameters that induced the best effect were determined. Tissues were harvested on the day prior to the treatment day and on days 3, 5, 7, 10 and 14 after CO2FL. H&E and immunofluorescence staining, RNA sequencing (RNA-seq), quantitative real-time polymerase chain reaction (qPCR), Western blotting (WB) and related inhibitor were used to determine the molecular mechanism underlying the effect of CO2FL treatment on the hair cycle and hair regrowth. In clinical trial, five participants were treated three sessions at 1-month intervals to obverse the effects. RESULTS: Hair regrew and covered the treatment area on the tenth day after CO2FL treatment with the best parameters, while the control group showed signs of hair growth on the 14th day. H&E and immunofluorescence staining showed that the transition of hair follicles (HFs) from telogen to anagen was accelerated, and the rapid activation and proliferation of Lgr5+ hair follicle stem cells (HFSCs) were observed in the treatment group. The RNA-seq, qPCR and WB results indicated that the Wnt pathway was significantly activated after CO2FL treatment. Improvement achieved with CO2FL treatment in clinical trial. CONCLUSIONS: The results of this study suggest that CO2FL treatment can promote hair regrowth by activating Lgr5+ HFSCs and upregulating the Wnt/ß-catenin pathway. Clinical trial results demonstrated that CO2FL treatment will be a promising therapeutic regimen for alopecia. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Antioxidant extracts from Dicerocaryum senecioides as active ingredients in semi-permanents and hair conditioners.

BACKGROUND: Different hair types respond differently to cosmetic treatments; hence, many options ought to be availed to the consumer. The purpose of this study was to evaluate the use of antioxidant extract from Dicerocaryum senecioides as active alternatives in hair semi-permanent waving and hair conditioning. METHODS: The antioxidant phytochemicals were first identified and isolated by thin-layer chromatography (TLC) and spraying with revealing agents. The antioxidant potency was determined by DPPH antiradical scavenging and ferric reducing power methods. The extract was incorporated in two different formulations to make the extract perm (bio-semi-permanent) and the antioxidant hair conditioner (AC). The formulations had their performance examined for hair curling and conditioning on Asian and African hair types. Hair damage was assessed by scanning the surface of treated samples on an attenuated total reflectance-Fourier transform infrared spectrometer (ATR-FTIR) and by quantifying lost protein on ultraviolet visible (UV-Vis) spectrophotometer. RESULTS: The extract antioxidant had an IC50 of 26.54 ± 0.34 µg/ml exhibiting greater antioxidant potency compared to the controls quercetin (38.84 ± 0.12 µg/ml) and ascorbic acid (35.22 ± 0.07 µg/ml). The extract perm had a lower curling ability indicated by a perm set of 85.10 ± 3.92% and 81.35 ± 2.35% for Asian and African hairs, respectively, while commercial product, ammonium thioglycolate (ATG) had 96.05 ± 1.70% and 93.60 ± 2.21% for the same. The curling of hair with extract perm resulted in less oxidative damage with oxidative peak areas of 3.37 ± 0.09 and 3.71 ± 0.03 as well as lower protein losses of 4.72 ± 0.71 µg/mg and 5.62 ± 0.70 µg/mg on Asian and African hair samples, respectively. The application of AC reduced the oxidative damage peak areas of ATG and extract perm treated Asian hair samples by 1.15 and 0.48 units, respectively. AC was also effective in reducing damage caused by UV radiation on ATG-treated samples by 1.06 units (African hair) and 1.09 units on Asian hair. CONCLUSION: The results show antioxidant extracts from Dicerocryum senecioides as a promising and safer alternative for hair conditioning and semi-permanent curling.

CONTEXTE: les réactions aux traitements cosmétiques varient d'un type de cheveux à l'autre. Ainsi, de nombreuses options doivent être mises à disposition des consommateurs. Cette étude avait pour objectif d'évaluer l'utilisation d'un extrait antioxydant de Dicerocaryum senecioides en vue de proposer de nouveaux choix de produits actifs pour les mises en plis semi-permanentes et le conditionnement capillaire. MÉTHODES: les agents phytochimiques antioxydants ont d'abord été identifiés et isolés par chromatographie sur couche mince (CCM) et par pulvérisation d'agents révélateurs. La puissance antioxydante a été déterminée par une méthode de piégeage antiradicalaire à l'aide du DPPH et par un procédé de puissance de réduction du fer. L'extrait a été incorporé dans deux formulations différentes pour obtenir la permanente (semi-permanentes biologiques) et l'après-shampooing capillaire antioxydant. Les performances des formulations ont été évaluées selon des critères de bouclage et conditionnement capillaires sur des cheveux de types asiatiques et africains. L'évaluation des lésions capillaires reposait sur un examen de la surface des échantillons traités à l'aide d'un spectromètre infrarouge à transformée de Fourier en réflectance totale atténuée (attenuated total reflectance Fourier transform infra-red spectrometer, ATR-FTIR) et sur une quantification des protéines perdues à l'aide d'un spectrophotomètre à ultraviolet visible (UV-Vis). RÉSULTATS: l'extrait antioxydant présentait une concentration inhibitrice médiane (IC50 ) de 26.54 ± 0.34 µg/ml, d'où une plus grande puissance antioxydante par rapport aux produits témoins, à savoir la quercétine (38.84 ± 0.12 µg/ml) et l'acide ascorbique (35.22 ± 0.07 µg/ml). La permanente présentait une plus faible capacité de bouclage, révélée par un taux de fixation de la permanente de 85.10 ± 3.92 % et de 81.35 ± 2.35 % pour les cheveux asiatiques et africains respectivement, tandis que le produit disponible dans le commerce, à savoir le thioglycolate d'ammonium (ATG), donnait des taux de 96.05 ± 1.70 % et de 93.60 ± 2.21 % dans les mêmes conditions. Le bouclage des cheveux à l'aide de la permanente a entraîné moins de lésions oxydatives, avec des zones de pics d'oxydation de 3.37 ± 0.09 et de 3.71 ± 0.03, ainsi que des pertes protéiques plus faibles, de 4.72 ± 0.71 µg/mg et de 5.62 ± 0.70 µg/mg sur les échantillons de cheveux asiatiques et africains respectivement. L'application de l'après-shampooing antioxydant a permis de réduire de 1.15 unité les zones de pics d'oxydation due à l'ATG sur les échantillons de cheveux asiatiques et la permanente a permis de traiter ces mêmes échantillons à raison de 0.48 unité. L'après-shampooing antioxydant s'est également avéré efficace pour réduire les lésions causées par les rayons UV sur les échantillons traités par ATG, de 1.06 unité sur les cheveux africains et de 1.09 unité sur les cheveux asiatiques. CONCLUSION: les résultats montrent que les extraits antioxydants de Dicerocaryum senecioides constituent une option prometteuse et plus sûre pour le conditionnement capillaire et les mises en pli semi-permanentes.

Photoreactivity of Hair Melanin from Different Skin Phototypes-Contribution of Melanin Subunits to the Pigments Photoreactive Properties.

Photoreactivity of melanin has become a major focus of research due to the postulated involvement of the pigment in UVA-induced melanoma. However, most of the hitherto studies were carried out using synthetic melanin models. Thus, photoreactivity of natural melanins is yet to be systematically analyzed. Here, we examined the photoreactive properties of natural melanins isolated from hair samples obtained from donors of different skin phototypes (I, II, III, and V). X-band and W-band electron paramagnetic resonance (EPR) spectroscopy was used to examine the paramagnetic properties of the pigments. Alkaline hydrogen peroxide degradation and hydroiodic acid hydrolysis were used to determine the chemical composition of the melanins. EPR oximetry and spin trapping were used to examine the oxygen photoconsumption and photo-induced formation of superoxide anion, and time-resolved near infrared phosphorescence was employed to determine the singlet oxygen photogeneration by the melanins. The efficiency of superoxide and singlet oxygen photogeneration was related to the chemical composition of the studied melanins. Melanins from blond and chestnut hair (phototypes II and III) exhibited highest photoreactivity of all examined pigments. Moreover, melanins of these phototypes showed highest quantum efficiency of singlet oxygen photogeneration at 332 nm and 365 nm supporting the postulate of the pigment contribution in UVA-induced melanoma.

Raman and photoluminescence spectroscopy analysis of gamma irradiated human hair.

Preliminary study has been made of black human hair, carbon concentration of some 53%, a model in examining the potential of hair of the human head in retrospective and emergency biodosimetry applications, also offering effective atomic number near to that of water. The hair samples were exposed to [Formula: see text]Co gamma rays, delivering doses from 0 to 200 Gy. Structural alterations were observed, use being made of Raman and photoluminescence (PL) spectroscopy. Most prominent among the features observed in the first-order Raman spectra are the D and G peaks, appearing at 1370 [Formula: see text] and 1589 [Formula: see text] respectively, the intensity ratio [Formula: see text] indicating dose-dependent defects generation and annealing of structural alterations. The wavelengths of the PL absorption and emission peaks are found to be centred at [Formula: see text] nm and [Formula: see text] nm, respectively. The hair samples mean band gap energy ([Formula: see text]) post-irradiation was found to be [Formula: see text] eV, of the order of a semiconductor and approximately two times the [Formula: see text] of other carbon-rich materials reported via the same methodology.

Assessment and Treatment Outcomes of Persistent Radiation-Induced Alopecia in Patients With Cancer.

Importance: Persistent radiation-induced alopecia (pRIA) and its management have not been systematically described. Objective: To characterize pRIA in patients with primary central nervous system (CNS) tumors or head and neck sarcoma. Design, Setting, and Participants: A retrospective cohort study of patients from January 1, 2011, to January 30, 2019, was conducted at 2 large tertiary care hospitals and comprehensive cancer centers. Seventy-one children and adults diagnosed with primary CNS tumors or head and neck sarcomas were evaluated for pRIA. Main Outcomes and Measures: The clinical and trichoscopic features, scalp radiation dose-response relationship, and response to topical minoxidil were assessed using standardized clinical photographs of the scalp, trichoscopic images, and radiotherapy treatment plans. Results: Of the 71 patients included (median [range] age, 27 [4-75] years; 51 female [72%]), 64 (90%) had a CNS tumor and 7 (10%) had head and neck sarcoma. Alopecia severity was grade 1 in 40 of 70 patients (56%), with localized (29 of 54 [54%]), diffuse (13 of 54 [24%]), or mixed (12 of 54 [22%]) patterns. The median (range) estimated scalp radiation dose was 39.6 (15.1-50.0) Gy; higher dose (odds ratio [OR], 1.15; 95% CI, 1.04-1.28) and proton irradiation (OR, 5.7; 95% CI, 1.05-30.8) were associated with greater alopecia severity (P < .001), and the dose at which 50% of patients were estimated to have severe (grade 2) alopecia was 36.1 Gy (95% CI, 33.7-39.6 Gy). Predominant trichoscopic features included white patches (16 of 28 [57%]); in 15 patients, hair-shaft caliber negatively correlated with scalp dose (correlation coefficient, -0.624; P = .01). The association between hair density and scalp radiation dose was not statistically significant (-0.381; P = .16). Twenty-eight of 34 patients (82%) responded to topical minoxidil, 5% (median follow-up, 61 [interquartile range, 21-105] weeks); 4 of 25 (16%) topical minoxidil recipients with clinical images improved in severity grade. Two patients responded to hair transplantation and 1 patient responded to plastic surgical reconstruction. Conclusions and Relevance: Persistent radiation-induced alopecia among patients with primary CNS tumors or head and neck sarcomas represents a dose-dependent phenomenon that has distinctive clinical and trichoscopic features. The findings of this study suggest that topical minoxidil and procedural interventions may have benefit in the treatment of pRIA.

Laser hair reduction for hidradenitis suppurativa warrants insurance coverage.

Hidradenitis suppurativa is a chronic, painful disease that significantly reduces quality of life. Laser hair reduction is one modality that can be used in combination with other treatments to ameliorate the condition. We argue that insurance should provide coverage for this necessary service.

A Combined Triple-Wavelength (755nm, 810nm, and 1064nm) Laser Device for Hair Removal: Efficacy and Safety Study.

BACKGROUND: Photoepilation by a single-wavelength laser device is being commonly used for hair removal. Whether emitting multiple laser wavelengths to induce hair unit damage would be beneficial is yet to be established. OBJECTIVE: To evaluate the safety and efficacy of hair reduction using a novel simultaneous multi-wavelength laser device. PATIENTS AND METHODS: A retrospective cohort study was carried out among adult males. Hairy sites were treated by a simultaneous triple-wavelength (755nm, 810nm and 1064nm) laser device (Soprano Titanium. Caesarea, Israel: Alma Lasers Ltd). Treatment parameters were: fluence of 7-9J/cm2, pulse frequency of 9-10Hz and spot sizes of 2cm2 or 4cm2. Participants underwent up to 6 treatments at 6-8 weeks intervals and were followed for 4-6 months. Clinical photography before and after treatment was documented. Treatment efficacy was assessed using Global Aesthetic Improvement Scale (GAIS; scale of 0 [no improvement] to 4 [excellent improvement; Over 75% hair reduction]) by two independent dermatologists. Participants’ satisfaction was rated on a scale of 1 (not satisfied) to 5 (very satisfied). Pain perception and adverse events were recorded as well. RESULTS: A total of 27 treatment sites among 11 participants, with Fitzpatrick skin type III-V, were included. Mean hair reduction was 3.4 out of 4 in the GAIS. Participants' satisfaction rate was high (mean, 4.8). No adverse events were recorded. CONCLUSION: Simultaneous triple-wavelength laser device is a safe and effective hair removal modality. J Drugs Dermatol. 2020;19(5): doi:10.36849/JDD.2020.4735.

Long-term Facial and Body Hair Removal With a Combined Radiofrequency and Optical Home-Use Device for All Skin Types.

OBJECTIVES: To evaluate long term effectiveness and safety with the use of a combined radiofrequency and optical home hair removal device in all skin types and over both facial and body areas. METHODS: A combined intense pulsed light (IPL) and radiofrequency (RF) home device was used for hair removal. Two separate study designs were evaluated. In the first design, bilateral body areas were treated with 7 weekly procedures and then unilateral areas received up to 12 monthly maintenance treatments while the corresponding other side received no further therapy. For the second design, facial areas received 4 procedures in 2 to 5 days visits, followed by 2 weekly, and then 6 biweekly procedures. All patients in both study designs had hair count evaluations up to 12 months post their last procedure. The highest energy used was 4 J/cm². RESULTS: In the first design, 58 subjects participated of which 15% were skin types V-VI. A total of 188 anatomical sites were treated. Hair reduction at 6 and 12 months post the last procedure was 56% and 52% respectively for the maintenance side and 47% and 37% for the non-maintenance side. For the second design, 19 subjects had 59 facial sites treated. Fifteen percent were skin types V –VI. The overall hair reduction at the end of receiving their procedures was 45%. At 12 months post the last procedure, the hair reduction was 42%. Aside for transient mild erythema, there were no adverse effects noted. CONCLUSIONS: Long term persistent hair reduction was achieved using an RF/IPL home-use hair reduction device. The combination of RF and optical energies allowed for the effective application of low energy usage. All skin types and both facial and body anatomical regions tolerated the procedures very well. J Drugs Dermatol. 2020;19(5):498-503. doi:10.36849/JDD.2020.4741.

Halloysite/Keratin Nanocomposite for Human Hair Photoprotection Coating.

We propose a novel keratin treatment of human hair by its aqueous mixtures with natural halloysite clay nanotubes. The loaded clay nanotubes together with free keratin produce micrometer-thick protective coating on hair. First, colloidal and structural properties of halloysite/keratin dispersions and the nanotube loaded with this protein were investigated. Above the keratin isoelectric point (pH = 4), the protein adsorption into the positive halloysite lumen is favored because of the electrostatic attractions. The ζ-potential magnitude of these core-shell particles increased from -35 (in pristine form) to -43 mV allowing for an enhanced colloidal stability (15 h at pH = 6). This keratin-clay tubule nanocomposite was used for the immersion treatment of hair. Three-dimensional-measuring laser scanning microscopy demonstrated that 50-60% of the hair surface coverage can be achieved with 1 wt % suspension application. Hair samples have been exposed to UV irradiation for times up to 72 h to explore the protection capacity of this coating by monitoring the cysteine oxidation products. The nanocomposites of halloysite and keratin prevent the deterioration of human hair as evident by significant inhibition of cysteic acid. The successful hair structure protection was also visually confirmed by atomic force microscopy and dark-field hyperspectral microscopy. The proposed formulation represents a promising strategy for a sustainable medical coating on the hair, which remediates UV irradiation stress.

Nanostructured lipid carriers: A novel hair protective product preventing hair damage and discoloration from UV radiation and thermal treatment.

The goal of this study was to investigate the protective effects of nanostructured lipid carriers (NLCs) and vitamin E loaded NLCs (Vit E-NLCs) on preventing hair damages and discoloration against UV radiation and thermal treatment. The NLCs and Vit E-NLCs were prepared using a high-pressure homogenization technique. At optimal conditions, they showed spherical particles with a mean particle size of ~140 nm and a polydispersity index of < 0.3. Up to 90% (w/w) vitamin E acetate incorporation efficacy was achieved. The protective efficacy of the model cream containing blank-NLCs (NLCs cream) or Vit E-NLCs (Vit E-NLCs cream) was investigated. Upon exposure to UV-light and heat, the FE-SEM images revealed that the hair treated with both NLCs creams showed a smoothness of hair surface similar to the virgin hair. In accordance with protein loss, they exhibited the least protein loss as compared to the hair treated with Vit-E cream, cream base and commercial products. The same trend was observed for the discoloration test, the hair treated with both NLCs creams demonstrated the lowest total color loss, as compared to other products. Comparing between two NLCs formulations, antioxidant Vit E-NLCs showed to promote the photoprotective effect against hair damage and discoloration slightly greater than blank NLCs, but it has no extra benefit for heat protection. Considered overall, the developed NLCs and Vit E-NLCs is a novel alternative for preventing hair damage and discoloration from daily UV and heat exposure.

UV damage to hair and the effect of antioxidants and metal chelators.

OBJECTIVE: To study the effects of addition of a redox metal, copper, antioxidants and metal chelators on the formation of free radicals in natural white Caucasian hair subsequently exposed to UV light. Three different methods, electron paramagnetic resonance (EPR), a fluorescent probe for hydroxyl radical formation (terephthalate) and free radical photoyellowing, were used. These methods utilized different UV sources and reaction conditions, and so can give insights into the different mechanisms of action occurring during UV oxidation of hair. In addition, this study demonstrates how antioxidants and chelators can be screened to determine whether they can protect hair from UV damage. RESULTS: The three methods gave somewhat different results, illustrating the importance of reaction conditions and wavelength on the photochemical mechanisms, and the efficacy of additives to influence these reactions. EPR results showed that N-acetylcysteine (NAC) pre-treatment eliminated the intensity of the signal because of sulphur and carbon free radicals in white hair both before and after exposure to UVB radiation. Doping the hair with copper ions had no effect on the intensity of the EPR signal under dry conditions. Terephthalate fluorescent probe data showed that under wet conditions, irradiation of white hair with UVA produced significant amounts of hydroxyl radicals. Pre-treatment of hair with NAC reduced the number of •OH radicals produced by natural white hair compared to an untreated control. In contrast to the EPR result, white hair doped with copper ions produced significantly higher levels of •OH radicals under wet conditions. It appears that the ability of copper ions to catalyse the photogeneration free radicals in hair is highly dependent on water content. Photoyellowing data showed a benefit for oxalic acid but no difference for NAC and an increase in yellowing for EDTA. CONCLUSION: The micro-EPR and terephthalate fluorescent probe methods are both effective techniques to study production of free radicals by hair exposed to UV light under wet and dry conditions, respectively. Both assays are simple methods for determining the effectiveness of potential protective hair treatments against UV damage, but because they assess free radical damage under dry vs wet conditions, the chemistry created on UV exposure is different. This gives insights into mechanism of action, but results may not be consistent between the two methods for actives added for reduction of UV damage. NAC pre-treatment did reduce free radical generation in UV-exposed hair under both wet and dry conditions. Photoyellowing data are more complicated as it is a less direct measure of UV damage and is highly dependent on irradiation source. Using UVB irradiation is experimentally convenient but may not be appropriate, because UVB wavelengths comprise only 0.3% of terrestrial sunlight. The photochemistry of hair exposed to sunlight involves concurrent photobleaching and photoyellowing processes and is far more complex. Under UVB irradiation conditions, oxalic acid showed a yellowing benefit.

OBJECTIF: Étudier les effets de l'ajout d'un métal redox, d'un cuivre, d'antioxydants et de chélateurs de métaux sur la formation de radicaux libres dans les cheveux naturels blancs de Caucasiens, exposés par la suite à des rayons  à ultraviolets. Trois méthodes différentes, la résonance paramagnétique électronique (RPE), une sonde fluorescente pour la formation de radicaux hydroxyles (téréphtalate) et le photojaunissement dû aux radicaux libres ont été utilisées. Ces méthodes ont utilisé différentes sources d'UV et de conditions de réaction, et peuvent par conséquent donner un aperçu des différents mécanismes d'action qui se produisent lors de l'oxydation des cheveux aux UV. Par ailleurs, cette étude montre comment les antioxydants et les chélateurs peuvent être analysés en vue de déterminer s'ils peuvent protéger les cheveux contre les dommages causés par les UV. RÉSULTATS: Les trois méthodes ont donné des résultats quelque peu différents, ce qui illustre l'importance des conditions de réaction et de la longueur d'onde sur les mécanismes photochimiques, ainsi que l'efficacité des additifs influençant ces réactions. Les résultats de la RPE ont montré que le traitement préalable par N-acétylcystéine (NAC) éliminait l'intensité du signal en raison de la présence du soufre et des radicaux libres de carbone dans les cheveux blancs, avant et après l'exposition aux rayons UVB. Le dopage des cheveux avec des ions de cuivre n'a eu aucun effet sur l'intensité du signal RPE en condition sèche. Les données des sondes fluorescentes de téréphtalate ont montré qu'en conditions humides, l'irradiation des cheveux blancs avec des UVA produisait d'importantes quantités de radicaux hydroxyles. Le traitement préalable des cheveux par N-acétylcystéine a réduit le nombre de radicaux hydroxyles produits par les cheveux blancs naturels comparé à un témoin non traité. Contrairement au résultat de la RPE, les cheveux blancs dopés avec des ions de cuivre ont produit des concentrations beaucoup plus élevées de radicaux hydroxyles en conditions humides. Il apparaît que la capacité des ions de cuivre à catalyser les radicaux libres photogénérés dans les cheveux dépend fortement de la teneur en eau. Les données relatives au photojaunissement ont démontré un avantage pour l'acide oxalique, aucune différence pour la N-acétylcystéine et une augmentation du jaunissement pour l'EDTA. CONCLUSION: Les méthodes de sonde fluorescente micro-RPE et téréphtalate sont deux techniques efficaces d'étude de la production de radicaux libres sur les cheveux exposés aux rayons ultraviolets en conditions humides et sèches, respectivement. Les deux tests sont des méthodes simples pour déterminer l'efficacité d'éventuels traitements de protection contre les dommages causés par les UV, mais étant donné qu'ils évaluent les dommages causés par les radicaux libres dans des conditions sèches ou humides, la réaction chimique créée lors de l'exposition aux UV est différente. Cela permet de mieux comprendre le mécanisme d'action, mais les résultats peuvent ne pas être cohérents entre les deux méthodes en raison des substances actives ajoutées pour réduire les dommages causés par les UV. Le traitement préalable par N-acétylcystéine a réduit la génération de radicaux libres dans les cheveux exposés aux UV en conditions humides et sèches. Les données de photojaunissement sont plus complexes, étant donné qu'il s'agit d'une mesure moins directe des dommages causés par les UV et qu'elles dépendent fortement de la source d'irradiation. L'utilisation de l'irradiation aux UVB est convenable d'un point de vue expérimental, mais peut ne pas être appropriée, car les longueurs d'onde UVB ne représentent que 0,3 % du rayonnement solaire terrestre. La photochimie de cheveux exposés à la lumière du soleil implique des processus de photoblanchiment et de photojaunissement concomitants, et est bien plus complexe. Dans des conditions d'irradiation aux UVB, l'acide oxalique a présenté un avantage en matière de jaunissement.

The effect of 1540-nm fractional erbium-glass laser in the treatment of androgenic alopecia.

BACKGROUND: Androgenic alopecia is common, chronic dermatologic disorder. A variety of lasers and light sources appear to be safe and effective in the treatment of AGA. AIMS: To evaluate the efficacy and safety of 1540-nm fractional erbium glass laser in the treatment of AGA. PATIENTS/METHODS: This was an interventional therapeutic study for the treatment of patients with AGA. The patients received 10 sessions with 1540-nm fractional erbium glass laser at 2-week intervals. The assessment of the response was done before and at the end of follow-up period, both objectively (the change in the density of terminal hair and the diameter of the hair shaft) and subjectively (patient satisfaction). Any adverse effects were documented during the study. RESULTS: Forty-seven out of 51 patients completed the study. After 5 months of laser treatment, the density of hair and hair thickness was significantly increased in both males and females (P value .001). CONCLUSION: The 1540-nm fractional erbium-glass laser seems to be an effective and safe option for treatment of patients with AGA. The improvement was accomplished in a short period.

NEUTRON DOSE ASSESSMENT USING SAMPLES OF HUMAN BLOOD AND HAIR.

The unique feature of nuclear accidents with neutron exposure is the induced radioactivity in body tissues. For dosimetry purposes, the most important stable isotopes occurring in human body, which can be activated by neutrons, are 23 Na and 32 S. The respective activation reactions are as follows:23Na(n,γ)24Na and32S(n,p)32P. While sodium occurs in human blood, sulfur is present in human hair. In order to verify the practical feasibility of this dosimetry technique in conditions of our laboratory, samples of human blood and hair were irradiated in a channel of a training reactor VR-1.24Na activity was measured by gamma-ray spectrometry.32P activity in hair was measured by means of a proportional counter. Based on neutron-spectrum calculation, relationships between neutron dose and induced activity were derived for both blood and hair.

Direct sunlight exposure reduces hair cortisol levels in rhesus monkeys (Macaca mulatta).

Major depressive disorder (MDD), commonly known as depression, is a mental disease characterized by a core symptom of low mood. It lasts at least two weeks (Badamasi et al., 2019; Wang et al., 2019) and is frequently accompanied by low self-esteem, loss of interest in routinely enjoyable activities, low energy, and unexplained pain (Huey et al., 2018; Park et al., 2012; Post & Warden, 2018; Rice et al., 2019; Xiao et al., 2018). Approximately 2%-8% of adults with MDD commit suicide (Richards & O'Hara, 2014; Strakowski & Nelson, 2015), and around half of suicidal individuals suffer depression or other mood disorders (Bachmann, 2018).

Self-Activated Electrical Stimulation for Effective Hair Regeneration via a Wearable Omnidirectional Pulse Generator.

Hair loss, a common and distressing symptom, has been plaguing humans. Various pharmacological and nonpharmacological treatments have been widely studied to achieve the desired effect for hair regeneration. As a nonpharmacological physical approach, physiologically appropriate alternating electric field plays a key role in the field of regenerative tissue engineering. Here, a universal motion-activated and wearable electric stimulation device that can effectively promote hair regeneration via random body motions was designed. Significantly facilitated hair regeneration results were obtained from Sprague-Dawley rats and nude mice. Higher hair follicle density and longer hair shaft length were observed on Sprague-Dawley rats when the device was employed compared to conventional pharmacological treatments. The device can also improve the secretion of vascular endothelial growth factor and keratinocyte growth factor and thereby alleviate hair keratin disorder, increase the number of hair follicles, and promote hair regeneration on genetically defective nude mice. This work provides an effective hair regeneration strategy in the context of a nonpharmacological self-powered wearable electronic device.

Human pollution exposure correlates with accelerated ultrastructural degradation of hair fibers.

Exposure to pollution is a known risk factor for human health. While correlative studies between exposure to pollutants such as polycyclic aromatic hydrocarbons (PAHs) and human health exist, and while in vitro studies help to establish a causative connection, in vivo comparisons of exposed and nonexposed human tissue are scarce. Here, we use human hair as a model matrix to study the correlation of PAH pollution with microstructural changes over time. Two hundred four hair samples from 2 Chinese cities with distinct pollution exposure were collected, and chromatographic-mass spectrometry was used to quantify the PAH-exposure profiles of each individual sample. This allowed us to define a group of less contaminated hair samples as well as a more contaminated group. Using transmission electron microscopy (TEM) together with quantitative image analysis and blind scoring of 82 structural parameters, we find that the speed of naturally occurring hair-cortex degradation and cuticle delamination is increased in fibers with increased PAH concentrations. Treating nondamaged hair fibers with ultraviolet (UV) irradiation leads to a more pronounced cortical damage especially around melanosomes of samples with higher PAH concentrations. Our study shows the detrimental effect of physiological concentrations of PAH together with UV irradiation on the hair microstructure but likely can be applied to other human tissues.

Chemical and physical treatments damage Caucasian and Afro-ethnic hair fibre: analytical and image assays.

BACKGROUND: Sensory and structural characteristics of hair can be modified by chemical and physical treatments, as dyeing, brushing, but also by external factors, as sunlight radiation. However, quantitative data relating damage to the degree of hair curliness and treatments are missing. OBJECTIVE: To evaluate the effect of chemical and physical treatments on different types of hair. METHODS: In this study, we compared the effects of bleaching/dyeing, thioglycolate-based straightening, brushing/flat iron and UVA/Vis radiation on different types of hair: Caucasian (straight dark brown, straight blond, wavy dark brown and curly dark brown) and Afro-ethnic hair. RESULTS: Bleaching/dyeing and UVA/Vis radiation increased combing work of Afro-ethnic hair tresses, indicating damage to the cuticle scales, which was confirmed by SEM images. Further, bleaching/dyeing caused wear on cuticles with high protein loss and reduction on the tryptophan content, independently of the hair curliness, which characterizes those procedures as very aggressive to hair structure. Straightening using ammonium thioglycolate, due to the oxidative treatment evolved, caused significant colour fading in brown/black tresses, while UVA/Vis radiation affected the colour of only blond hair tresses since they are poor in eumelanin, the photoprotective and photostable melanin molecule. CONCLUSION: The combination of analytical and image techniques contributed to understanding how the hair shape is related to the type of damage caused by several chemical and physical treatments. These findings contribute to the development of safety cosmetics that insure the beauty of curly hair, both Caucasian and Afro-ethnic hair.