A Cre knockin mouse reveals specific expression of Agouti gene in mesenchymal lineage cells in multiple organs and provides a unique tool for conditional gene targeting.

The mouse Agouti gene encodes a paracrine signaling factor which promotes melanocytes to produce yellow instead of black pigment. It has been reported that Agouti mRNA is confined to the dermal papilla after birth in various mammalian species. In this study, we created and characterized a knockin mouse strain in which Cre recombinase was expressed in-frame with endogenous Agouti coding sequence. The Agouti-Cre mice were bred with reporter mice (Rosa26-tdTomato or Rosa26-ZsGreen) to trace the lineage of Agouti-expressing cells during development. In skin, the reporter was detected in some dermal fibroblasts at the embryonic stage and in all dermal fibroblasts postnatally. It was also expressed in all mesenchymal lineage cells in other organs/tissues, including eyes, tongue, muscle, intestine, adipose, prostate and testis. Interestingly, the reporter expression was excluded from epithelial cells in the above organs/tissues. In brain, the reporter was observed in the outermost meningeal fibroblasts. Our work helps to illustrate the Agouti expression pattern during development and provides a valuable mouse strain for conditional gene targeting in mesenchymal lineage cells in multiple organs.

Genipa americana L.: A New Phytochemical for White Hair Coloring.

This work describes a new hair dyeing methodology using a chemical reaction between geniposide, an iridoid glycoside extracted from the fruit of Genipa americana (geniposide extract, GE) and the amine group of hair keratin. The influence of reaction conditions (pH, temperature, and extract concentration) on the staining of hair fibers, color development, fiber morphology, and mechanical hair properties of black and white human hair samples, was evaluated before and after GE dyeing treatment. Eye contact safety of GE was also studied using HET-CAM. The treatment of white hair fibers using GE at 20 mg mL-1 , temperature of 80 °C and pH 5.5 presented the greatest color change (ΔE=54.0). The higher pH influence was observed at pH 10.0 on white hair tresses (ΔE=6.8), using an GE concentration of 20 mg mL-1 and room temperature (25 °C). Treated samples showed marked changes on mechanical and morphological properties. The HET-CAM did not show any change, thus demonstrating that using GE is safe. In conclusion, the temperature and concentration of the extract were the variables that mostly influenced the color and hair damage. A new approach for hair dyeing was established where iridoids may potentially be useful as a natural hair dyeing.

Chemical Scalp Burn after Hair Coloring-Case Report with Literature Review.

Hair dyeing is widely performed around the world. Chemical and thermal burns can result from the components present in brightening and coloring products, as well as the application process. We present a case of a chemical burn after applying hair dye and review the literature on similar cases, the composition of hair dyes, their mechanism of action, and the process of burns. The patient was a 17-year-old girl, who presented to the Dermatology Clinic with a 13 × 10 cm ulcer on the scalp after hair dyeing in a hairdressing salon. General and local treatment was applied, with particular emphasis on specialized dressings. The ulcer site was replaced by an area of scarring after 11 months of treatment. Based on the presented case and the review of the literature, we conclude that hair dye treatments warrant careful attention for potential scalp complications. The diagnostic and therapeutic approach demands a multidisciplinary effort, with ongoing patient-doctor cooperation throughout the treatment, which may complicate and span several months.

Brightness and hue judgment of dyed hair color.

This study aims to investigate human hair color perception through two empirical studies in the context of colored hair. The preliminary study was intended to establish a numerical representation of perceptually meaningful brightness levels. It identified that the brightness level was proportional to the power of 0.766 of L*. In the visual assessment, participants (N = 47) categorized 246 hair color samples into eight color hue groups aligned with the Munsell system. Hue judgment was conducted by visually comparing dyed hair tresses with natural black hair. Based on the L*, a*, and b* values of hair tresses and visual assessments thereof, we observed the ranges of hue categories for hair color alongside the brightness levels. Additionally, the differences between the Munsell hue names and the assessment results were compared. Predominantly influenced by the dark brown hair color, the neutral orientation was shifted to the first quadrant of the a*-b* plane. The study contributes to an understanding of human hair color perception and provides insights into color categorization and labeling, especially when the context is confined.

Assessing the dyeing efficiency and irritation potentials of plant hair dyes: A multi-analytical in vitro approach.

BACKGROUND: The interest toward dyeing hairs with plant colorants has grown in popularity considering its low-toxic nature. However, researches reporting plant hair dyes are limited and the potential adverse effects of irritation are unclear. OBJECTIVES: This study is aimed to provide an avenue by which to more accurately assess the dyeing efficiency and irritation potentials of plant hair dyes. METHODS: Four extracted plant colorants were incorporated in hydrogel hair dyes that were directly applied on unbleached gray human hairs. Their dyeing performances and the effect of an iron (Ⅱ) mordant were photometrically measured in CIELab coordinates and color strength. The eye and skin irritancy was assessed by combining various in vitro methods, including bovine corneal opacity and permeability (BCOP) assay in combination with histopathological analysis, Hen's egg test on chick chorioallantoic membrane (HET-CAM) and a test on reconstructed human epidermis models. RESULTS: The investigated hair dyes exhibited desirable dyeing efficiency on human hairs. Post-treatment with the iron (Ⅱ) mordant caused a significant increase in color strength with subtle changes to the hue of dyed color. In the irritation testing, the four hair dyes were categorized as slight-to-mild eye irritants but possessed no skin irritation potential, while the mordant was determined as a non-irritant. CONCLUSIONS: The results demonstrate the efficacy of a multi-analytical approach for in vitro assessment of various plant colorants for hair dyeing. The investigated plant extracts are suitable for producing viable colors on human hairs and may serve as a low-irritating alternative to the synthetic hair dyes.

Microstructured prealloyed Titanium-Nickel powder as a novel nonenzymatic hydrogen peroxide sensor.

At present, commercial pure Titanium (Ti) and microstructured pre-alloyed Titanium-Nickel (TiNi) powders are employed as a sensitive electrochemical hydrogen peroxide (H2O2) sensor. Surface characterization of these materials are performed by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical characterization is achieved via cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) on Ti and TiNi modified glassy carbon electrode (GCE). The electrochemical behavior of H2O2 at the pure Ti/GCE and microstructure pre-alloyed TiNi/GCE are studied by CV in 0.1 M phosphate buffer solution (PBS) containing as the supporting electrolyte. In addition, CA is employed for the determination of H2O2 at the applied potential of 0 V vs. Ag/AgCl. The sensor has a linear response range of 0.5-17.5 mM with a sensitivity of 280 µA mM-1 cm-2. Moreover, the limit of detection (LOD) and limit of quantification (LOQ) are 0.5 µM and 1.7 µM, respectively. The electrochemical sensor exhibits fast and selective responses to H2O2 concentration. The applicability of the sensor is checked using a hair coloring as a real sample with satisfactory results.

Spontaneous subcutaneous emphysema of the scalp following hair coloring/treatment.

Subcutaneous emphysema of the scalp is a process often attributed to secondary factors such as trauma, infection, or a myriad of iatrogenic etiologies. Here, we are presenting a case report of an adult patient with spontaneous subcutaneous emphysema of the scalp following a hair coloring/treatment. We performed an extensive review of literature on this topic, however, could not find a single case with similar presentation of subcutaneous emphysema. This case demonstrates an unreported etiology for this diagnosis and is thus being reported for its uniqueness and to raise clinical awareness.

A Study on Scalp Hair Health and Hair Care Practices among Malaysian Medical Students.

INTRODUCTION: Scalp care is essential because it determines the health and condition of the hair and prevents the diseases of scalp and hair. The objectives of our study were to correlate race and hair types, to determine the awareness of hair care among Malaysian medical students, and to distinguish the factors that affect the health of hair and scalp. METHODOLOGY: It was a cross-sectional study wherein validated questionnaires were given to 240 medical undergraduate students who belonged to three ethnic races of Malaysia, i.e., Chinese, Malay, and Malaysian Indians after their informed consent. The results were then analyzed using percentage statistics. RESULTS: Chinese students had comparatively healthier scalp without dandruff. Most Chinese and Indians had silky type of hair while Malay had dry, rough hair. Chinese and Indians colored their hair and used various styling methods; while among the Malays, this percentage was very less. Regarding hair care practices, males used only shampoo and females used shampoo and conditioner for hair wash. Students also faced dietary and examination-related stress. CONCLUSION: Results indicate that there exist morphological differences in hair among the studied population. Since most students color their hair and employ various hairstyling methods, they should be educated regarding best hair care practices to improve their scalp hair condition and health.