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Microneedling, a minimally invasive procedure involving repeated puncturing of the skin with sterilized microneedles, has gained popularity for treating various dermatological concerns. Its ability to stimulate collagen production makes it effective for skin rejuvenation, scar reduction, and hair regrowth. Recent studies demonstrate its enhanced efficacy when combined with other treatments, such as minoxidil, platelet-rich plasma, and exosomes for hair regeneration. Additionally, microneedling shows promise in managing conditions like vitiligo and melasma when used alongside topical therapies. The expanding applications of microneedling highlight its versatility, with combination therapies proving more effective than monotherapies for optimal patient outcomes. [ABSTRACT FROM AUTHOR]

Background: Personalized medicine, an emerging approach, considers individual differences to tailor treatments optimally. Persian medicine (PM) incorporates individual differences through Mizāj (temperament). A comprehensive understanding of each Mizaj type's characteristics is essential in designing standardized diagnostic tools. Objectives: This study aims to explore the attributes of one of the most significant Mizaj groups, namely cold-wet Mizaj, and its subtypes, including cold-wet Su-e-Mizaj (dystemperament), as well as phlegm dominance in PM sources. Methods: Persian medicine literature, including the Canon of Medicine, was reviewed for relevant concepts. Reliable scientific databases, including PubMed, Scopus, and MagIran, were searched using keywords such as Mizaj, temperament, Su-e-Mizaj, dystemperament, cold-wet dystemperament, phlegm, and Balgham. The obtained results were studied and categorized. Results: Out of the 196 articles obtained related to Mizaj, 16 investigated indices. No studies were found on the indices of coldwet Mizaj and phlegm dominance separately. PM sources exhibit high congruence in describing the characteristics of cold-wet Mizaj. Specifically, emphasis is placed on characteristics such as coldness and softness of the skin to the touch, high fat mass, pale and white complexion, excessive body secretions, weakness and slowness of physical and physiological actions, low vitality, timidity, poor memory, and slow-wittedness. In cold-wet dystemperament, symptoms are more severe, and in the presence of phlegm, a feeling of heaviness is also mentioned as a specific symptom. Conclusions: By compiling indices of cold-wet Mizaj/dystemperament and phlegm dominance, this study can contribute to the development of standardized PM questionnaires, facilitating a personalized approach to the diagnosis and treatment of diseases. [ABSTRACT FROM AUTHOR]

Touch sensitivity generally declines with age, contributing to loss of manual dexterity and tactile function. We investigated how touch changes over the lifespan, using different tests and on three body sites. We used a classical test of force detection sensitivity, where calibrated monofilaments were applied passively to the right index finger pad, forearm, and cheek. In addition, at the index, we used an active touch spatial discrimination task, developed by our group. Spatial discrimination was estimated through participants' ability to evaluate the distance between parallel bands printed on acrylic plates. Data were collected from 96 healthy women, aged 20-75 years. Force detection and tactile spatial discrimination on the index deteriorated significantly with age; however, no change was found for tactile detection on the forearm or cheek. Tactile detection on the cheek remained remarkably highly sensitive throughout life. There was a significant positive relationship between force detection and spatial discrimination on the index. Further, force detection on the forearm was significantly associated with detection on the index and cheek. Our results suggest a decrease in touch perception with age on the index finger pad, yet a preservation of tactile sensitivity in hairy skin. This opens discussion about the impact of daily activities upon the glabrous hand skin and on the function of hairs in tactile sensitivity. We highlight the need for new methods in evaluating tactile sensitivity on hairy skin. [ABSTRACT FROM AUTHOR]

This study aimed at investigating the effect of a food supplement in ameliorating the skin, hair, and nails conditions. An open-label study on 21 women with mild-to-moderate aging all over the face (including wrinkles/fine lines, loss of skin firmness/elasticity, and normal to dry skin), acute telogen effluvium, and brittle/fragile nails was conducted. Skin (moisturization, elasticity, profilometry, and skin thickness), hair (pull test and phototricogram), and nails (clinical analysis of nail plate status) parameters were measured at baseline, and after 28 and 84 days of intake. The clinical analysis carried out by a board-certified dermatologist and the self-evaluation integrated the instrumental measurements. After 28 (D28) and 84 (D84) days of product intake the skin moisturization (superficial moisturization: +6.0% at D28 and +9.2% at D84; deep moisturization: +4.2% at D28 and +7.6 at D84), elasticity (R0 parameter: -11.5% at D28 and -19.3% at D84; R2 parameter: +7.8% at D28 and +11.9 at D84), profilometry (wrinkle depth: -9.5% at D28 and -14.5% at D84; skin smoothness: -4.9% at D28 and -7.7% at D84) and thickness (+0.11 mm at D28 and +0.24 mm at D84) were improved. At D84 the density of telogen hair was reduced by 9.5%; while at day 28 pull test was not indicative for telogen effluvium. The nail status was improved in most of the enrolled subjects. The instrumental measured effects were perceived by both the dermatologist and the enrolled subjects. Our results highlight the test product efficacy in improving the skin, hair, and nails conditions. [ABSTRACT FROM AUTHOR]

Background and Design: Premature graying of hair (PGH) is a clinical entity with multiple ramifications such as low self- esteem, inferiority complex and may interfere with an individual's social interaction capabilities and adversely affect the individual's psychosocial health. This study aimed to investigate the biochemical factors and knowledge, attitude, and practice in patients with PGH. Materials and Methods: A case control study including 75 cases and equal number of age and sex matched controls was conducted in a tertiary care hospital. Various epidemiological variables and biochemical parameters (vitamin B12, vitamin D, calcium, iron profile, lipid profile, thyroid hormones) were ascertained and compared between the cases and controls. The severity of graying was assessed using the Graying Severity Score, and a knowledge, attitude, and practice study was conducted by administering a pre-validated questionnaire to assess the impact on the quality of life of these affected individuals. Results: Significant differences between cases and controls in the serum levels of biochemical parameters, namely Vitamin B12 (p=0.001), vitamin D (p=0.004), serum iron (p<0.001), ferritin (p<0.001) and total iron binding capacity, i.e TIBC (p=0.037) and thyroid hormones T4 (p=0.002) and thyroid stimulating hormone (p=0.041) was found. No correlation between PGH and serum calcium and lipid profile was derived. Also, a statistically significant difference was noted in the appetite pattern of cases and controls (p=0.003). Stress, smoking, altered sleep pattern and bowel habits were also more prevalent in cases as compared to controls. It was also noted that most study cases belonged to the lower middle class of the modified Kuppuswamy scale. The Knowledge, Attitudes, and Practices (KAP) study, which was extremely comprehensive and detailed in nature, showed that PGH significantly affects these patients' quality of life. Conclusion: The study reveals a strong association between PGH and deficiency of vitamin D, abnormal levels of vitamin B12, hypothyroidism and deranged iron profile, and altered appetite patterns. Along with this, the prevalence of stress, smoking, altered sleep patterns and bowel habits was also higher in PGH cases. Hence, all these parameters should be analysed in such patients. KAP analysis was a unique approach to studying common conceptions and practices in PGH cases and its' psychological impact. [ABSTRACT FROM AUTHOR]

Background: Exposure to socioeconomic adversity is hypothesized to impact hypothalamic–pituitary–adrenal (HPA) axis activity and cortisol secretion, but existing evidence is inconsistent. Yet, few studies have investigated this association using a developmental approach that considers potential protective contextual factors. This study examined the role of stability and changes in family socioeconomic status (SES) in the prediction of multiple cortisol indicators and tested whether social support moderated these associations. Methods: Participants were part of a population‐based sample of twin pairs recruited at birth. Family SES was assessed in early childhood (ages 0–5) and mid‐adolescence (age 14). Social support was assessed at ages 14 and 19. Diurnal cortisol (n = 569) was measured at age 14 at awakening, 30 min later, in the afternoon and evening over four non‐consecutive days. Hair cortisol concentration (HCC, n = 704) was measured at age 19. All data were collected before the pandemic and multilevel regression models were conducted to account for the nested data structure. Results: Youth exposed to lower family SES levels in childhood and mid‐adolescence had a flatter diurnal slope and higher HCC compared with those who experienced upward socioeconomic mobility in mid‐adolescence. Contrastingly, mid‐adolescence SES showed no association with the diurnal slope or HCC for youth from higher‐SES households in early childhood. Moreover, youth raised in higher‐SES families in early childhood had a higher CAR in mid‐adolescence if they reported greater social support in mid‐adolescence. Social support also moderated the SES‐cortisol association in mid‐adolescence, with higher‐SES youth showing higher awakening cortisol secretion when reporting more social support. Conclusions: Our findings support the hypothesis that early socioeconomic adversity sensitizes HPA axis activity to later socioeconomic disadvantage, which may bear consequences for socioemotional and behavioral functioning. [ABSTRACT FROM AUTHOR]

Nutritional status of patients, specially prolonged starvations is an important sub-component of the environmental factors, speculated to have indirect impact on the initiation, propagation, resolution, and exacerbation stages of autoimmunity. The study was based on the hypothesis of conscious, selective, and self-destruction, that is, deregulated autophagy of skin and hair in low dietary protein scenario triggered with prolonged starvations. It was aimed to reverse the self-destruction/deregulated autophagy by providing early morning, low carb-high protein nutrition, and correcting underlying micronutrient deficiency and studying its effect on reducing auto-immunity and eventually reducing disease burden and recurrence. Methods: In this retrospective study, patients were divided into two categories based on disease activity and nutrition. Group A: "novice group" of vitiligo patients who presented at an early stage of their disease were managed with basic standard of therapeutics. Group B: "stabilized group" of vitiligo who were given surgical treatment and followed up for 3 years for any recurrences. Personalized diet plan aimed at reversing high carb-low protein diet and avoiding prolonged overnight starvation adhering to early morning breakfast respecting the circadian rhythm and balanced with additional plant based protein was advised. All detectable underlying micronutrient deficiencies were corrected. Results: Thirty patients were enrolled in the study, 20 in group A and 10 in group B. We observed visible signs of improvement in group A, with early vitiligo (90%) with topical therapy and nutritional intervention as early as 3 weeks. Following surgical procedure in group B, 50% patients had near complete pigmentation at the end of 3 months and 30% within next 3 months. At the end of 6 months, all patients had significant improvement in VASI and VIDA score, however two patients in each group had recurrence at end of 1 year who deviated from nutritional protocol and were found to be deficient in protein intake and micronutrients deficiency was detected on blood investigation. The improvement in VASI scores with conventional treatment and nutritional intervention was found to be statistically significant at 6 months and 1-year interval in group A with paired t test (P=0.013). Similarly, improvement in VASI was statistically very significant at 6 months and 1- year duration in surgically treated vitiligo group B (P=0.001). These patients were put on immunosuppressive therapies in first group after correction of deficiencies and managed with supportive and conventional therapy in second group in subsequent 3 years follow up. Conclusion: Nutritious diet aimed at correction of underlying protein and micronutrient deficiency with special emphasis on circadian rhythm may arrest the natural progression of disease at an early stages of the disease and prime the body for oral immunosuppressive drugs. This approach may prevent the recurrence in patients already stabilized with standard care of therapeutics and surgery in future. [ABSTRACT FROM AUTHOR]

The hair follicle is a complex of mesenchymal and epithelial cells acquiring different properties and characteristics responsible for fulfilling its inductive and regenerative role. The epidermal and dermal crosstalk induces morphogenesis and maintains hair follicle cycling properties. The hair follicle is enriched with pluripotent stem cells, where dermal papilla (DP) cells and dermal sheath (DS) cells constitute the dermal compartment and the epithelial stem cells existing in the bulge region exert their regenerative role by mediating the epithelial-mesenchymal interaction (EMI). Many studies have developed and focused on various methods to optimize the EMI through in vivo and in vitro approaches for hair regeneration. The culturing of human hair mesenchymal cells resulted in the loss of trichogenicity and inductive properties of DP cells, limiting their potential application in de novo hair follicle generation in vivo. Epithelial stem cells derived from human hair follicles are challenging to isolate and culture, making it difficult to obtain enough cells for hair regeneration purposes. Mesenchymal stem cells and epithelial stem cells derived from human hair follicles lose their ability to form hair follicles during culture, limiting the study of hair follicle formation in vivo. Therefore, many attempts and methods have been developed to overcome these limitations. Here, we review the possible and necessary cell methods and techniques used for human hair follicle regeneration and the restoration of hair follicle cell inductivity in culture.

Background: An earlier oscillator model for the generation of spontaneous otoacoustic emissions (SOAEs) from the lizard ear is extended with a connection of the oscillators to the basilar papilla, to make it possible that these SOAEs can be transported to the tympanic membrane, to be emitted. Material and methods: The generators of spontaneous otoacoustic emissions are modelled as a one-dimensional array of Hopf-resonators. The resonators (or oscillators) are coupled to their neighbours, and to the basilar papilla. The papilla is modelled as a rigid structure, that is flexibly connected to its surroundings. Results: Frequency spectra are given for different sets of coupling parameters, both for nearest neighbour coupling of the oscillators, and for coupling to the papilla, and also after the introduction of irregularities in the damping of the oscillators. Waterfall and density plots show clustering of the oscillators in frequency plateaus, and entrainment of a cluster of oscillators by an externally applied sinusoidal force. All these model outcomes correspond with characteristics of SOAEs emitted by real lizard ears. Conclusions: The present model is a useful extension of an earlier model. Because its characteristics differ from that of a model that is used to describe the generation of SOAEs by mammalian ears, it revives the discussion whether different models are needed for SOAE generation in different animal species [ABSTRACT FROM AUTHOR]

The application of photobiomodulation (PBM) in regenerative medicine has expanded to the treatment of alopecia caused by various reasons. However, the mechanisms responsible for its effects are poorly understood. Here, we aimed to investigate the effects of PBM on hair regeneration in injured skin and to explore the underlying mechanisms. The scratched epidermis or dermis models were established in C57 mice aged 7–8 weeks. We found that the scratched epidermis had no influence on hair regeneration, but the scratched dermis led to obvious hair follicle atrophy and significantly influenced hair regeneration. The wounds in scratched dermis models were treated with PBM (655 nm, 3 J/cm2 [10 min]) and the hair regeneration and cell proliferation in hair follicle were evaluated. Compared with control, the hair coverage level was significantly enhanced after PBM treatment. Sox9+ and PCNA+ cells in hair follicle were obviously observed in PBM‐treated group, but not in control. In vitro, the effects of PBM on the function of dermal papilla cells (DPCs) were investigated. The results showed that the migration of DPCs was increased significantly by PBM (655 nm, 3 J/cm2 [10 min]), whereas no effect was found on proliferation. Furthermore, we found that PBM promoted exosome secretion of DPCs, accompanied by the activation of Akt/GSK‐3β/β‐catenin pathway. AKT inhibitor MK‐2206 effectively blocked PBM‐induced migration and exosome secretion of DPCs. These findings suggest that the enhanced migration and exosome secretion of DPCs mediated by the Akt/GSK‐3β/β‐catenin pathway were responsible for the promotion of hair regeneration in injured skin by PBM. [ABSTRACT FROM AUTHOR]

This article will look at the general description of hair as a skin appendage, its normal growth phase, resting phase and shedding phase. It will also consider the psychosocial impact and psychosocial influences that hair loss patients have throughout their lives. Dermatology nurses should be aware of the main hair loss and scalp conditions, so handy hints on what to do and what not to do to keep hair and scalp healthy will also be included. [ABSTRACT FROM AUTHOR]

Bats rely on their hand-wings to execute agile flight maneuvers, to grasp objects, and cradle young. Embedded in the dorsal and ventral membranes of bat wings are microscopic hairs. Past research findings implicate dorsal wing hairs in airflow sensing for flight control, but the function of ventral wing hairs has not been previously investigated. Here, we test the hypothesis that ventral wing hairs carry mechanosensory signals for flight control, prey capture, and handling. To test this hypothesis, we used synchronized high-speed stereo video and audio recordings to quantify flight and echolocation behaviors of big brown bats (Eptesicus fuscus) engaged in an aerial insect capture task. We analyzed prey-capture strategy and performance, along with flight kinematics, before and after depilation of microscopic hairs from the bat's ventral wing and tail membranes. We found that ventral wing hair depilation significantly impaired the bat's prey-capture performance. Interestingly, ventral wing hair depilation also produced increases in the bat's flight speed, an effect previously attributed exclusively to airflow sensing along the dorsal wing surface. These findings demonstrate that microscopic hairs embedded in the ventral wing and tail membranes of insectivorous bats provide mechanosensory feedback for prey handling and flight control., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The article examines the efficacy and safety of BLH308, a herbal product comprising persimmon leaf, green tea, and Japanese sophora extracts, in enhancing hair growth. It discusses significant increases in hair density and thickness in participants consuming BLH308 compared to placebo, alongside safety assessments and suggestions for future research on its effects across different demographic and environmental conditions affecting hair health.

Hair, having distinct stages of growth, is a dynamic component of the integumentary system. Nonetheless, derangement in its structure and growth pattern often provides vital clues for the diagnosis of systemic diseases. Assessment of the hair structure by various microscopy techniques is, hence, a valuable tool for the diagnosis of several systemic and cutaneous disorders. Systemic illnesses like Comel-Netherton syndrome, Griscelli syndrome, Chediak Higashi syndrome, and Menkes disease display pathognomonic findings on hair microscopy which, consequently, provide crucial evidence for disease diagnosis. With minimal training, light microscopy of the hair can easily be performed even by clinicians and other health care providers which can, thus, serve as a useful tool for disease diagnosis at the patient's bedside. This is especially true for resource-constrained settings where access and availability of advanced investigations (like molecular diagnostics) is a major constraint. Despite its immense clinical utility and non-invasive nature, hair microscopy seems to be an underutilized diagnostic modality. Lack of awareness regarding the important findings on hair microscopy may be one of the crucial reasons for its underutilization. Herein, we, therefore, present a comprehensive overview of the available methods for hair microscopy and the pertinent findings that can be observed in various diseases. [ABSTRACT FROM AUTHOR]

Transcranial Magnetic Stimulation (TMS) is a technique that is frequently utilized in neuroscience for both therapeutic and research purposes. TMS offers critical medical services like treating major depression and is vital in almost every research facility. Because TMS relies on scalp placement, hair is thought to affect efficacy because it varies the distance to the target site. Further, it is presumed that the hair textures and length that are predominantly seen in minoritized persons might pose significant challenges to collecting high-quality data. Here, we present preliminary data demonstrating that TMS may be influenced by hair, particularly in historically underrepresented minoritized groups. The Sol braiding approach is introduced here as an easy-to-learn, quick-to-implement technique that reduces variability in TMS. Compared across nine participants, it was found that the Sol method significantly increased motor evoked potential (MEP) strength and consistency (p < 0.05). By removing the physical hair barrier that impedes direct coil-to-scalp contact, the Sol approach enhances TMS delivery. The MEP peak amplitude and the MEP area under the curve (AUC) were shown to increase as a result. While preliminary, these data are an important step in addressing diversity in neuroscience. These procedures are explained for non-braiding experts.

We aimed to analyze the seasonal acclimatization process of Nelore and Canchim cattle raised on two production systems (non-shaded, NS, and integrated crop-livestock-forest, ICLF), based on the dynamics of the morphological and functional attributes of the hair coat and skin during winter and summer. The study was conducted in Brazil, in a low-altitude tropical climate region. A completely randomized 2 × 2 factorial design was adopted as follows: two production systems (NS and ICLF), two breeds (Nelore and Canchim) in a longitudinal structure, with measurements repeated over time through two stations (winter and summer). The experimental animals consisted of 32 Nelore (Bos indicus) and 32 Canchim (5/8 Bos taurus × 3/8 Bos indicus) bulls. The animals were equally distributed between two intensive rotational grazing systems. In both breeds, the hair coat was significantly thicker in winter but longer in summer, which increased epidermal protection. The Nelore bulls had shorter, wider, and thicker hairs, which are attributes that promote heat loss via conduction. The Canchim bulls showed significantly lower hair density and higher epithelium distance to sweat glands, which resulted in higher core temperature and respiratory rate. In turn, Nelore bulls had higher serum concentrations of triiodothyronine and lower serum concentrations of cortisol. However, Canchim bulls more frequently and intensely activated their thermoregulatory system and markedly adjusted their hair coat and hair features to reduce heat gain, especially in summer. Therefore, the anatomical plasticity and functional integumentary characteristics of Nelore and Canchim bulls reflect their acclimatization to tropical conditions., (© 2024. The Author(s).)

Hair loss and thinning have always been a huge concern for men and women across the globe. Numerous treatments have been tried and tested, ranging rom folk remedies to chemical products. Unfortunately, none have proven a regular efficacy, without mentioning the possible side effects. So, for a long time, the only real option was hair graft. Now, with technological advances in both growth factors and stem cells, we have a possible solution that is efficient, safe and reproducible: platelet-rich plasma. [ABSTRACT FROM AUTHOR]

Follicular proteoglycans are key players with structural, functional, and regulatory roles in the growth and cycling behaviour of the hair follicles. The expression pattern of specific proteoglycans is strongly correlated with follicular phase transitions, which further affirms their functional involvement. Research shows that bioactive proteoglycans, e.g., versican and decorin, can actively trigger follicular phase shift by their anagen-inducing, anagen-maintaining, and immunoregulatory properties. This emerging insight has led to the recognition of "dysregulated proteoglycan metabolism" as a plausible causal or mediating pathology in hair growth disorders in both men and women. In support of this, declined expression of proteoglycans has been reported in cases of anagen shortening and follicular miniaturisation. To facilitate scientific communication, we propose designating this pathology "follicular hypoglycania (FHG)," which results from an impaired ability of follicular cells to replenish and maintain a minimum relative concentration of key proteoglycans during anagen. Lasting FHG may advance to structural decay, called proteoglycan follicular atrophy (PFA). This process is suggested to be an integral pathogenetic factor in pattern hair loss (PHL) and telogen effluvium (TE). To address FHG and PFA, a proteoglycan replacement therapy (PRT) program using oral administration of a marine-derived extract (Nourkrin® with Marilex®, produced by Pharma Medico Aps, Aarhus, Denmark) containing specific proteoglycans has been developed. In clinical studies, this treatment significantly reduced hair fall, promoted hair growth, and improved quality of life in patients with male- and female-pattern hair loss. Accordingly, PRT (using Nourkrin® with Marilex®) can be recommended as an add-on treatment or monotherapy in patients with PHL and TE. [ABSTRACT FROM AUTHOR]

According to the dual mating strategy model, in short-term mating contexts women should forego paternal investment qualities in favor of mates with well-developed secondary sexual characteristics and dominant behavioral displays. We tested whether this model explains variation in women's preferences for facial masculinity and beardedness in male faces. Computer-generated composites that had been morphed to appear ± 50% masculine were rated by 671 heterosexual women (M age = 31.72 years, SD = 6.43) for attractiveness when considering them as a short-term partner, long-term partner, a co-parent, or a friend. They then completed the Revised Sociosexual Inventory (SOI-R) to determine their sexual openness on dimensions of desire, behavior, and attitudes. Results showed that women's preferences were strongest for average facial masculinity, followed by masculinized faces, with feminized faces being least attractive. In contrast to past research, facial masculinity preferences were stronger when judging for co-parenting partners than for short-term mates. Facial masculinity preferences were also positively associated with behavioral SOI, negatively with desire, and were unrelated to global or attitudinal SOI. Women gave higher ratings for full beards than clean-shaven faces. Preferences for beards were higher for co-parenting and long-term relationships than short-term relationships, although these differences were not statistically significant. Preferences for facial hair were positively associated with global and attitudinal SOI, but were unrelated to behavioral SOI and desire. Although further replication is necessary, our findings indicate that sexual openness is associated with women's preferences for men's facial hair and suggest variation in the association between sociosexuality and women's facial masculinity preferences. [ABSTRACT FROM AUTHOR]

Peroxisome proliferator‐activated receptors (PPARs) are abundantly expressed in human skin, with PPAR‐γ being the most intensively investigated isoform. In various ex vivo and in vivo models, PPAR‐γ‐mediated signalling has recently surfaced as an essential element of hair follicle (HF) development, growth and stem cell biology. Moreover, the availability of novel, topically applicable PPAR‐γ modulators with a favourable toxicological profile has extended the range of potential applications in clinical dermatology. In this review, we synthesize where this field currently stands and sketch promising future research avenues, focussing on the role of PPAR‐γ‐mediated signalling in the biology and pathology of human scalp HFs, with special emphasis on scarring alopecias such as lichen planopilaris and frontal fibrosing alopecia as model human epithelial stem cell diseases. In particular, we discuss whether and how pharmacological modulation of PPAR‐γ signalling may be employed for the management of hair growth disorders, for example, in scarring alopecia (by reducing HF inflammation as well as by promoting the survival and suppressing pathological epithelial‐mesenchymal transition of keratin 15 + epithelial stem cells in the bulge) and in hirsutism/hypertrichosis (by promoting catagen development). Moreover, we explore the potential role of PPAR‐γ in androgenetic alopecia, HF energy metabolism and HF ageing, and consider clinical perspectives that emanate from the limited data available on this so far. As this field of translational human hair research is still in its infancy, many open questions exist, for which we briefly delineate selected experimental approaches that promise to generate instructive answers in the near future. [ABSTRACT FROM AUTHOR]

The article presents current data on the role growth factors play in hair physiology. Based on a review of literature, the authors described the role growth factors play for initiating, suppressing the growth and differentiating hair follicles. According to them, each morphologic development stage of hair follicles is characterized by its own factor expression pattern. Referring to experimental and clinical studies, the authors describe the role some growth factors play for mechanisms promoting the development of androgynous and focal alopecia.

Introduction: Functional near-infrared spectroscopy (fNIRS) is a promising tool for studying brain activity, offering advantages such as portability and affordability. However, challenges in data collection persist due to factors like participant physiology, environmental light, and gross-motor movements, with limited literature on their impact on fNIRS signal quality. This study addresses four potentially influential factors-hair color, hair cleanliness, environmental light, and gross-motor movements-on fNIRS signal quality. Our aim is to raise awareness and offer insights for future fNIRS research., Methods: Six participants (4 Females, 2 Males) took part in four different experiments investigating the effects of hair color, hair cleanliness, environmental light, and gross-motor movements on fNIRS signal quality. Participants in Experiment 1, categorized by hair color, completed a finger-tapping task in a between-subjects block design. Signal quality was compared between each hair color. Participants in Experiments 2 and 3 completed a finger-tapping task in a within-subjects block design, with signal quality being compared across hair cleanliness (i.e., five consecutive days without washing the hair) and environmental light (i.e., sunlight, artificial light, no light, etc.), respectively. Experiment 4 assessed three gross-motor movements (i.e., walking, turning and nodding the head) in a within-subjects block design. Motor movements were then compared to resting blocks. Signal quality was evaluated using Scalp Coupling Index (SCI) measurements., Results: Lighter hair produced better signals than dark hair, while the impact of environmental light remains uncertain. Hair cleanliness showed no significant effects, but gross motor movements notably reduced signal quality., Conclusion: Our results suggest that hair color, environmental light, and gross-motor movements affect fNIRS signal quality while hair cleanliness does not. Nevertheless, future studies with larger sample sizes are warranted to fully understand these effects. To advance future research, comprehensive documentation of participant demographics and lab conditions, along with signal quality analyses, is essential., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Holmes et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Female androgenetic alopecia (FAGA) is a common cause of non-scarring alopecia in women. The onset may be at any age following puberty and the frequency increases with age. Clinically, it shows a diffuse hair thinning over the central scalp, while the frontal hairline is usually retained. FAGA can have a significant psychological impact, leading to anxiety and depression. For this reason, early diagnosis is very important to stop the progression of the disease. The sex hormonal milieu is the main pathogenetic mechanism studied in FAGA. The role of androgens is not clearly defined and only one-third of women with FAGA show abnormal androgen levels. Endocrinological diseases with hyperandrogenism associated with FAGA comprise polycystic ovarian syndrome (PCOS), hyperprolactinemia, adrenal hyperplasia and, rarely, ovarian and adrenal tumours. Usually the diagnosis of FAGA is made clinically. A complete clinical examination and a blood examination can reveal other signs of hyperandrogenism. Trichoscopy shows the typical hair miniaturization. A scalp biopsy can be useful when the clinical evaluation does not provide a definitive diagnosis or when cicatricial alopecias with hair loss in the distribution of FAGA or alopecia areata are suspected. FAGA is a slowly progressive disease. The goal of therapy is to stop the progression and to induce a cosmetically acceptable hair regrowth. The most important drugs are topical minoxidil and oral anti-androgens. The purpose of this review is to provide an update on FAGA and to create a guideline on diagnosis and management of this frequent hair disease, not always easily recognizable from cicatricial alopecias with a similar distribution. [ABSTRACT FROM AUTHOR]

Background: Corticosteroids are the most common agents used in the treatment of alopecia areata (AA), however, their long-term use is associated with severe side effects. Therefore, other immunosuppressive agents have been tried and azathioprine appears to be an effective and promising alternative. Objective: The main objective of this study was to compare the efficacy of 300 mg once weekly azathioprine pulse (WAP) and 5 mg betamethasone on 2 consecutive days every week in the management of AA. Materials and Methods: In this open-label, randomized comparative study, 50 patients of AA with >10% scalp area involvement were treated with either 300 mg WAP or 5 mg betamethasone on 2 consecutive days every week for 4 months or till complete scalp hair regrowth and followed up for next 5 months. Primary efficacy parameters were average percentage scalp hair regrowth and change in average Severity of Alopecia Tool (SALT) score at 4 months. Results: Twenty patients in WAP group and 21 patients in betamethasone group completed the study. The median percent scalp hair regrowth and the median change in SALT score was 44.52 and 9.5 in WAP group compared to 71.43 and 14 in betamethasone group at 4-month, respectively, which were statistically similar in two groups, however, side effects were significantly higher in betamethasone group. On further follow-up at 9 months, 10 (50%) patients in WAP group and 13 (62%) patients in betamethasone group achieved complete hair regrowth. Lack of control group was a limitation of our study. Conclusion: WAP and betamethasone therapy, both appear to be effective in the treatment of AA. However, betamethasone caused several side effects; therefore, WAP can be used as a better alternative to corticosteroids in AA. [ABSTRACT FROM AUTHOR]

Many insects have triplets of camera type eyes, called ocelli, whose function remains unclear for most species. Here, we investigate the ocelli of the bumblebee, Bombus terrestris, using reconstructed 3D data from X-ray microtomography scans combined with computational ray-tracing simulations. This method enables us, not only to predict the visual fields of the ocelli, but to explore for the first time the effect that hair has on them as well as the difference between worker female and male ocelli. We find that bumblebee ocellar fields of view are directed forward and dorsally, incorporating the horizon as well as the sky. There is substantial binocular overlap between the median and lateral ocelli, but no overlap between the two lateral ocelli. Hairs in both workers and males occlude the ocellar field of view, mostly laterally in the worker median ocellus and dorsally in the lateral ocelli. There is little to no sexual dimorphism in the ocellar visual field, suggesting that in B. terrestris they confer no advantage to mating strategies. We compare our results with published observations for the visual fields of compound eyes in the same species as well as with the ocellar vision of other bee and insect species. [ABSTRACT FROM AUTHOR]

Coat clipping is a common practice in sport horses; however, timing, purpose, technique, and clips vary widely, as do the management and feeding of a clipped horse. The aim of this study was to collect data regarding common clipping practices. A questionnaire was published online in Germany and contained 32 questions. Four hundred ninety-eight people answered at least one question, and 373 individuals (7% male, 93% female; ages 14-59 years) completed all the questions. Clipped horses were predominantly used as sport horses (68%), and they were either clipped immediately before or during the winter season (88%) or year-round (7%). The clipping date was scheduled according to hair length (52%), sweat amount (47%), and drying time (47%). Participants primarily used two clips: the hunter clip and the blanket clip, both without clipping the head (23% each). The majority of the clipped horses wore a blanket day and night (> 90%). Future studies with observations in the field are needed to support survey data in an effort to develop welfare recommendations for clipping practices utilized with horses. [ABSTRACT FROM AUTHOR]

Hair shape affects the frictional properties and tactile sensation of hair. In this study, we evaluated the friction associated with the rubbing of straight, curly, or wavy hair by a contact probe equipped in a sinusoidal motion friction evaluation system. This system provides dynamic information such as the velocity dependence and hysteresis of the frictional force. In the case of hair fibers fixed at 1 mm intervals on a glass plate, a stable friction pattern was observed, in which the friction coefficient was almost constant during the dynamic friction process. The friction coefficients in the inward direction toward the hair root for straight, curly, and wavy hair were 0.47 ± 0.04, 0.51 ± 0.02, and 0.54 ± 0.04, respectively. As wavy hair is thick and has a larger true contact area with the contact probe, the friction coefficient was larger. When the finger model rubbed the straight or curly hair bundle in the inward direction, an oscillation pattern was observed, with the friction coefficient fluctuating at 20 ms intervals and the kinetic friction coefficient evaluated at 0.67 and 0.64, respectively. For the surface of straight hair, containing densely arranged cuticles, a large oscillation was observed in the direction against the cuticles. Meanwhile, no oscillation phenomenon was observed in wavy hair, which is characterized by a smooth cuticle and complex hair flow. Because wavy hair, which is frizzy, has fewer points of contact between hairs, impeding the occurrence of cooperative fluctuations in the frictional force.

The health of hair is directly related to people's health and appearance. Hair has key physiological functions, including skin protection and temperature regulation. Hair follicle (HF) is a vital mini-organ that directly impacts hair growth. Besides, various signaling pathways and molecules regulate the growth cycle transition of HFs. Hair and its regeneration studies have attracted much interest in recent years with the increasing rate of alopecia. Mesenchymal stem cells (MSCs), as pluripotent stem cells, can differentiate into fat, bone, and cartilage and stimulate regeneration and immunological regulation. MSCs have been widely employed to treat various clinical diseases, such as bone and cartilage injury, nerve injury, and lung injury. Besides, MSCs can be used for treatment of hair diseases due to their regenerative and immunomodulatory abilities. This review aimed to assess MSCs' treatment for alopecia, pertinent signaling pathways, and new material for hair regeneration in the last 5 years.

Background: The relationship between female pattern hair loss (FPHL) and androgenic hormones is not well established, but some evidence indicates oral finasteride may be efficacious in FPHL. Use of a topical formulation has been proposed to minimize unwanted effects.Objectives: Our objective was to compare the efficacy and safety of topical 0.25% finasteride combined with 3% minoxidil solution and 3% minoxidil solution as monotherapy in the treatment of FPHL.Methods: This was a prospective, randomized, double-blind study in 30 postmenopausal women with FPHL. Each participant was randomized to receive either topical 0.25% finasteride combined with topical 3% minoxidil or topical 3% minoxidil solution as monotherapy for 24 weeks. To determine efficacy, the hair density and diameter was measured and global photographic assessment was conducted at baseline and 8, 16, and 24 weeks. Side effects and serum dihydrotestosterone levels were also evaluated.Results: By 24 weeks, hair density and diameter had increased in both groups, and finasteride/minoxidil was significantly superior to minoxidil solution in terms of hair diameter (p = 0.039). No systemic side effects were reported. However, serum dihydrotestosterone levels in the finasteride/minoxidil group significantly decreased from baseline (p = 0.016).Conclusion: A topical combination of 0.25% finasteride and 3% minoxidil may be a promising option in the treatment of FPHL with an additional benefit of increasing hair diameter. Nevertheless, as it may be absorbed percutaneously, it should be reserved for postmenopausal women.Trial Registration: clinicaltrials.in.th; identifier TCTR20160912002. [ABSTRACT FROM AUTHOR]

This study investigated the relationship between length of hair in facial stimuli and latency and amplitude of the P1 and N170 components of event-related potentials during facial perception. Electroencephalography was recorded from 21 Japanese participants (four men, 17 women) who were shown pictures of faces with one of three lengths of hair: long, medium length, or short. In addition, we used both fixed-size and variable-size blocks. In fixed-size blocks, the three types of stimuli were matched to have the same overall size; in variable-size blocks, long hair stimuli were the biggest, medium length hair stimuli were medium sized, and short hair stimuli were the smallest. We analyzed P1 latency and amplitude using two-way (6 x 2) repeated-measures analysis of variance over length of hair and electrode; N170 latency and amplitude were analyzed using three-way (6 x 2 x 2) repeated-measures analysis of variance over length of hair, hemisphere, and electrode. The latency of P1 to faces with short hair in variable-size blocks was significantly longer than that to the other five stimulus types (p < .01 for four of the other types; p = .083 for medium length hair in variable-size blocks). The latency of N170 to faces with long hair in variable-size blocks was significantly shorter than that to faces with medium length hair and short hair in variable-size blocks (p = .026 and p = .086, respectively). These results indicate that length of hair influenced P1 and N170 latency, supporting the notion that length of hair is a significant external facial feature. Because long hair attracted participants' attention, there was early perceptual processing of this feature. In contrast, because short hair did not attract attention, perceptual processing of this feature was late. [ABSTRACT FROM AUTHOR]

Apart from the skin surface, hair represents a significant tissue component with a capacity of bacterial interactions. New information can be obtained about hair function through the characterization of bacterial adherence, colonization, and responses to hair shafts per se. In this proof-of-principle study, we examine the growth kinetics of Gram-positive Staphylococcus aureus and Staphylococcus epidermidis, and Gram-negative Pseudomonas aeruginosa and Escherichia coli in the presence of human hair shafts. We explore the ability of these bacteria to adhere to and colonize hair shaft surfaces, as well as the resulting impact on the hair’s surface morphology. We show that hair shafts inhibit the growth of Gram-positive S. aureus and S. epidermidis , while the growth kinetics of P. aeruginosa and E. coli remain unaffected. Scanning electron microscope analysis and steeping studies show that P. aeruginosa and E. coli to adhere to and colonize on human hair shafts without significantly affecting the hair shaft’s surface morphology. P. aeruginosa produced a substantial amount of biofilm on the hair shaft surfaces, while E. coli specifically inhabited the edges of the cuticle scales. Taken together, our results demonstrate differences in bacterial responses to human hair shafts, which may provide novel insights into hair and scalp health. [ABSTRACT FROM AUTHOR]

This article examines how non-fiction children’s television programmes portray bodily changes and sexuality at puberty. Engaging with the body and the sexuality of children in the broadcast media raises cultural and social challenges. Public concern about social morality and the ‘sexualisation of children’, sexual objectification and pornography, together with the construction of childhood as a naïve pre-sexual stage of life, have silenced children’s television when it comes to the subject of children’s sexuality. However, a few programmes have offered an alternative to this taboo. Based on a study of 30 non-fiction programmes submitted between 1964 and 2016 to Prix Jeunesse international festival for children’s media, this paper describes and analyses how these programmes present unique, thought-provoking and innovative ways of engaging with the culturally controversial issue of the body and sexuality on children’s television. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the hair growth-promoting effect of Miscanthus sinensis var. purpurascens (MSP) flower extracton on in vitro and in vivo models.Methods: MSP flower extract was extracted in 99.9% methanol and applied to examine the proliferation of human dermal papilla cells (hDPCs) in vitro at the dose of 3.92-62.50 μg/mL and hair growth of C57BL/6 mice in vivo at the dose of 1000 μg/mL. The expression of transforming growth factor β1 (TGF-β1), hepatocyte growth factor (HGF), β-catenin, substance P was measured by relative quantitative realtime polymerase chain reaction. Histopathological and immunohistochemical analysis were performed.Results: MSP (7.81 μg/mL) down-regulated TGF-β1 and up-regulated HGF and β-catenin in hDPCs (P<0.01). MSP (1000 μg/mL)-treated mice showed the earlier transition of hair follicles from the telogen to the anagen phase. The number of mast cells was lower in the MSP-treated mice than in other groups (P<0.05 vs. NCS group). Substance P and TGF-β1 were expressed in hair follicles and skin of the MSP group lower than that in negative control. Stem cell factor in hair follicles was up-regulated in the MSP-treated mice (P<0.01).Conclusions: The MSP flower extract may have hair growth-promotion activities. [ABSTRACT FROM AUTHOR]

Previous studies have shown that androgenic alopecia is associated with metabolic syndrome and diabetes. However, the detailed mechanism whereby diabetes causes alopecia still remains unclear. We focused on the inflammatory response that is caused by diabetes or obesity, given that inflammation is a risk factor for hair loss. Inducible nitric oxide synthase (iNOS) is known to be upregulated under conditions of acute or chronic inflammation. To clarify the potential role of iNOS in diabetes-related alopecia, we generated obese diabetic iNOS-deficient ( ob/ob; iNOS-KO mice). We observed that ob/ob; iNOS-KO mice were potentiated for the transition from telogen (rest phase) to anagen (growth phase) in the hair cycle compared with iNOS-proficient ob/ob mice. To determine the effect of nitric oxide (NO) on the hair cycle, we administered an iNOS inhibitor intraperitoneally (compound 1400 W, 10 mg/kg) or topically (10% aminoguanidine) in ob/ob mice. We observed that iNOS inhibitors promoted anagen transition in ob/ob mice. Next, we administered an NO donor (S-nitrosoglutathione, GSNO), to test whether NO has the telogen elongation effects. The NO donor was sufficient to induce telogen elongation in wild-type mice. Together, our data indicate that iNOS-derived NO plays a role in telogen elongation under the inflammatory conditions associated with diabetes in mice. [ABSTRACT FROM AUTHOR]

Quantifying cortisol concentration in hair is a non‐invasive biomarker of long‐term hypothalamic‐pituitary‐adrenal (HPA) activation, and thus can provide important information on laboratory animal health. Marmosets (Callithrix jacchus) and capuchins (Cebus apella) are New World primates increasingly used in biomedical and neuroscience research, yet published hair cortisol concentrations for these species are limited. Review of the existing published hair cortisol values from marmosets reveals highly discrepant values and the use of variable techniques for hair collection, processing, and cortisol extraction. In this investigation we utilized a well‐established, standardized protocol to extract and quantify cortisol from marmoset (n = 12) and capuchin (n = 4) hair. Shaved hair samples were collected from the upper thigh during scheduled exams and analyzed via methanol extraction and enzyme immunoassay. In marmosets, hair cortisol concentration ranged from 2,710 to 6,267 pg/mg and averaged 4,070 ± 304 pg/mg. In capuchins, hair cortisol concentration ranged from 621 to 2,089 pg/mg and averaged 1,092 ± 338 pg/mg. Hair cortisol concentration was significantly different between marmosets and capuchins, with marmosets having higher concentrations than capuchins. The incorporation of hair cortisol analysis into research protocols provides a non‐invasive measure of HPA axis activity over time, which offers insight into animal health. Utilization of standard protocols across laboratories is essential to obtaining valid measurements and allowing for valuable future cross‐species comparisons. [ABSTRACT FROM AUTHOR]

Digit hair tourniquets are relatively uncommon. There are reports in the literature of hair tourniquets involving other appendages, such as the penis and uvula, however the phenomenon is not widely recognised and is often overlooked by healthcare professionals. This article discusses two case studies in which hair was responsible for creating a tourniquet around a digit. The article explores possible causes and management options for patients, with reference to the case studies. Midwives and health visitors are central to minimising the risk of injury to children as they can educate expectant mothers about this potential problem. [ABSTRACT FROM AUTHOR]

Immigration and epidemiological studies provide evidence indicating the correlation of high ultraviolet exposure during childhood and increased risks of melanoma in later life. While the explanation of this phenomenon has not been found in the skin, a class of hair has been hypothesized to be involved in this process by transmitting sufficient ultraviolet rays along the hair shaft to possibly cause damage to the stem cells in the hair follicle, ultimately resulting in melanoma in later life. First, the anatomy of hair and its possible contribution to melanoma development, and the tissue optical properties are briefly introduced to provide the necessary background. This paper emphasizes on the review of the experimental studies of the optical properties of human hair, which include the sample preparation, measurement techniques, results, and statistical analysis. The Monte Carlo photon simulation of human hair is next outlined. Finally, current knowledge of the optical studies of hair is discussed in the light of their possible contribution to melanoma development; the necessary future work needed to support this hypothesis is suggested. [ABSTRACT FROM AUTHOR]

Abstract: Background: Mexican mestizo population has a pluriethnic mixture of Amerindian, European and African ancestry, predominant in most Latin American countries. Until now, there are no reports about hair characteristics in this population, necessary to define normal values, for hair diseases evaluation and comparison among other ethnic groups. Methods: The VivoSight® swept‐source multibeam optical coherence tomography system was used to evaluate hair diameter and shape in 30 females. Three hair samples from each volunteer were measured transversely along three distances, generating nine cross‐sectional images, two measurements per image and 18 measurements per patient for a total of 540 diameter measurements. Results: Minimum hair diameter (n = 540) was 0.06 mm while maximum was 0.14 mm. Mean diameter was 0.10 ± 0.01 mm as compared with Asian hair, which ranges from 0.08 mm to 0.12 mm. On morphological analysis, Mexican Mestizo hair tends to have a round shape with homogenous diameters, resembling Caucasian and Asian hair. Conclusion: Mexican hair is similar to Asian hair in diameter and shape and can be classified as ‘thick’ hair, which make it more resistant and with more volume. Cosmetic products intended to improve hair care in this population must to consider this characteristic. [ABSTRACT FROM AUTHOR]

Reconstructing the scalp and forehead is a challenging endeavor frequently undertaken by facial plastic and reconstructive surgeons. There are many anatomical factors to be considered in this area, including multiple neurovascular structure present that should be identified and preserved. Hair morphology and physiology should be considered, and trichophytic techniques should be incorporated into incision planning and closure. The reconstructive ladder must be used when considering options in reconstructing scalps and forehead defects. This article reviews reconstructive options including secondary intention, primary closure, skin grafting, allografts, tissue expanders, and local, regional, and free tissue transfers, among others in the surgical management of forehead and scalp defects. The reconstructive surgeon should be familiar with these techniques and be able to use them when indicated, based on the size, shape, and location of defects. [ABSTRACT FROM AUTHOR]

Abstract: Objective: In the process of hair treatment, various cationic actives contained in hair care products can be absorbed into hair fibre to modulate the physicochemical properties of hair such as colour, strength, style and volume. There have been very limited studies on the binding and partition properties of hair care actives to hair. This study aimed to investigate the pH effects on cationic solute absorption into hair and binding to keratin. Methods: The keratin binding and hair partition properties of three cationic solutes (theophylline, nortriptyline and amitriptyline) have been measured at different pH using fluorescence spectroscopy and equilibrium absorption experiment. The binding constants, thermodynamic parameters and hair‐water partition coefficients determined at different pH were compared and analysed. Results: Increasing the pH from 2.0 to 6.0 resulted in the net charge of hair keratin changed from positive to negative. As a consequence, the binding constants of the three cationic solutes with keratin increased with the increasing pH. This correlated with the variation of the electrostatic interaction between cationic solutes and keratin from repulsion to attraction. The positive ΔH and ΔS values indicated that hydrophobic interaction also played a major role in the binding of the three cationic solutes to keratin. There was a good correlation between solutes binding to keratin and hair–water partition of solutes. Conclusion: It appears that solute binding to hair keratin is driven first by hydrophobic interaction and then by electrostatic interaction. The fitted thermodynamic parameters suggested that hydrophobic interaction dominates for the binding of the three cationic solutes to keratin. That binding of cationic solutes to keratin correlates with the partition of the solutes to hair could provide theoretical guidance for further developing mathematical models of hair partition and penetration properties. [ABSTRACT FROM AUTHOR]

Aims Contrary findings exist on the consistency between hair cortisol and salivary cortisol in assessing the basal activity of the hypothalamic-pituitary-adrenal (HPA) axis. The mismatches in temporal characteristic and the indices of hair and salivary cortisol might be potential reasons for the inconsistency. The aim of this study was to investigate the consistency between hair and salivary levels in cortisol and cortisone by directly examining the correlation between hair level and salivary level with different temporal characteristics (acute, short-term and long-term levels) and reflecting different HPA functions (basal level and reactivity level) in the well-matched time span. Main methods A longitudinal design within a five-week period was conducted in a sample of 44 healthy female college students (mean age: 18.8 yrs.; age range: 18–22 yrs) of Han nationality with the exclusion criteria, such as use of oral contraceptives or glucocorticoids and bleached hairs, etc. Four saliva samples (awakening, awakening + 30 min, awakening + 4 h and awakening + 9 h) were collected from an identical participant on three separate days with an interval of one week and 1-cm hair segment nearest to the scalp was collected two weeks later after completing saliva collection. Cortisol and cortisone in saliva and hair were simultaneously measured with high performance liquid chromatography tandem mass spectrometry. Key findings There were significantly moderate correlations in cortisol and cortisone between hair level and three-day average of single-day salivary level, but low to moderate correlations between hair level and single-point and single-day salivary level. Hair cortisol and cortisone were unrelated to single-day level and three-day average of diurnal slope and cortisol awakening response of salivary cortisol and cortisone, respectively. Significance The considerable consistency between hair level and long-term salivary level in cortisol and cortisone implies that cortisol and cortisone in hair are valid biomarkers of cumulative exposure of cortisol and cortisone to retrospectively reflect long-term basal activity of the HPA system. [ABSTRACT FROM AUTHOR]

Background Several factors are known contribute to hair cortisol concentration (HCC) in adults. However, there is less research on determinants of HCC in children and adolescents. HCC is a valuable tool for medical research pertaining to the hypothalamic-pituitary-adrenal (HPA) axis. This review aims to assess the extent to which established determinants of HCC in adults have been consistently reported in children (birth – 18 years) and to identify determinants of HCC specific to this age group. Methods Eligible studies were identified, selected and appraised as per PRISMA-P guidelines and as detailed in our systematic review protocol, registered on PROSPERO (registration number CRD42017056220). In view of contrasting methods and measures, a meta-analysis could not be done but a qualitative synthesis was performed. Results Thirty-six studies were included in the analysis. Higher HCC is associated with male sex and anthropometry, particularly increased body mass index and waist circumference. There is preliminary evidence to suggest that socio-economic status is inversely related to child HCC, particularly with reference to caregiver education and income. Of note, most of the studies analysing socio-economic variables were performed in relatively equal societies. Hair wash frequency and use of hair products and treatments do not affect HCC when proximal segments of hair are used. There is conflicting evidence regarding the relationship between HCC and age in children and adolescents. Further investigation is required to better delineate if and how the following are associated with HCC in children: hair colour, hair type, exposure to trauma and stressors, psychiatric illness, atopic illness, steroid use (including topical and inhaled steroids) and perinatal variables. Conclusions Sex and anthropometry are potential confounders and should be considered for adjustment in hair cortisol research. Hair wash frequency and use of hair products and treatments are not important confounders when proximal hair segments are used. A better understanding of HCC in children in relation to exposure to trauma and stressors is required before it can be used as a biomarker, particularly in terms of vulnerable developmental stages, definition and measurement of stress, and temporal relationship to stressors. Age, SES and other correlates also warrant further investigation. [ABSTRACT FROM AUTHOR]

Purpose: High-quality orofacial somatosensory inputs are essential for achieving rapid and accurate motor outputs. Little somatosensory testing is currently being completed in clinical settings. The purpose of this study is to assess the feasibility and test–retest reliability of clinical assessment tools for orofacial somatosensory testing in healthy young adults. Method: A total of 45 healthy young adults (ages 20– 41 years) was recruited. Participants reported basic health information, completed pure-tone hearing thresholds, and were assessed using two-point discrimination discs and Von Frey hair detection and discrimination thresholds for bilateral lip and tongue. A subsample of participants (n = 18; 40%) returned to complete reliability testing. Results: Descriptive results are presented for the normative group as well as the reliability group. Difference scores between Tests 1 and 2 for each testing measure and location show high agreement. Conclusion: Two-point discrimination and Von Frey hair monofilament assessment for both detection- and discrimination-threshold estimates have high test–retest reliability in a healthy young population. These testing measures could be a way to easily complete objective somatosensory testing of the orofacial region in a clinical context. [ABSTRACT FROM AUTHOR]

BACKGROUND: Nicotine concentration in hair is a useful marker of tobacco exposure. Detection of nicotine in the hair of nonsmokers indicates passive smoking. Accurate measurement of nicotine among active and passive smokers can help in smoking cessation programs or programs designed to prevent secondhand smoke exposure. OBJECTIVE: To establish, using high-performance liquid chromatography-ultraviolet detection (HPLC/UV), a hair nicotine cut-off value to distinguish active from passive smokers. METHODS: Hair samples were collected from randomly chosen Japanese men (n = 192) between 2009 and 2011. Nicotine and cotinine levels in hair were measured using HPLC/UV with column-switching. T-tests and chi-square tests were performed to compare active and passive smokers, while receiver operating characteristic curves were used to evaluate the effectiveness of the cut-off value. RESULTS: There were 69 active smokers and 123 passive smokers. The nicotine and cotinine concentrations in hair were significantly higher in active than in passive smokers (p < 0.01). The area under the curve for nicotine was 0.92. A hair nicotine cut-off value of 5.68 ng/mg, with a sensitivity of 94.2% and specificity of 87.0%, was identified as the optimal cut-off value for separating active from passive smokers. CONCLUSION: Nicotine and cotinine concentrations in hair clearly distinguished active from passive smokers. [ABSTRACT FROM AUTHOR]

Background: The appearance of the scalp and hair is very important aesthetically regardless of age or sex. Although there are many drugs and treatment methods for scalp problems and hair loss, the treatment response is still insufficient. Aims and Objectives: To evaluate the efficacy of low-level light therapy in a helmet-like device. Materials and Methods: This study was designed as a 24-week trial with 50 participants. All participants used a helmet-shaped device emitting 630–690, 820–880, and 910–970 nm light wavelengths, for 20 minutes, daily for 24 weeks. A phototrichogram for hair density and thickness, Global Aesthetic Improvement Scale score, erythema index, and sebum secretions of the scalp were evaluated at baseline and at 12 and 24 weeks. Results: After 24 weeks of treatment, hair density and hair thickness were found to have significantly increased (P <.01 and P =0.013, respectively) and sebum secretion of vertex area had decreased significantly (P <.01). Of 49 participants, 73.47% of the participants showed improvement in the overall appearance of the scalp (n = 36). Conclusion: A helmet-like low-level light therapy device can improve the appearance of the hair, with thickening and increase in the density of the hair, and can improve scalp condition by decreasing sebum secretion. [ABSTRACT FROM AUTHOR]

Humans are unique among mammals in having a functionally naked body with a hair-covered scalp. Scalp hair is exceptionally variable across populations within Homo sapiens . Neither the function of human scalp hair nor the consequences of variation in its morphology have been studied within an evolutionary framework. A thermoregulatory role for human scalp hair has been previously suggested. Here, we present experimental evidence on the potential evolutionary function of human scalp hair and variation in its morphology. Using a thermal manikin and human hair wigs at different wind speeds in a temperature and humidity-controlled environment, with and without simulated solar radiation, we collected data on the convective, radiative, and evaporative heat fluxes to and from the scalp in relation to properties of a range of hair morphologies, as well as a naked scalp. We find evidence for a significant reduction in solar radiation influx to the scalp in the presence of hair. Maximal evaporative heat loss potential from the scalp is reduced by the presence of hair, but the amount of sweat required on the scalp to balance the incoming solar heat (i.e., zero heat gain) is reduced in the presence of hair. Particularly, we find that hair that is more tightly curled offers increased protection against heat gain from solar radiation.