The use of personal hair dye and its implications for human health

Healthy lifestyle choices: new insights into vitiligo management

Background

The treatment of vitiligo is complex, and providing guidance based on lifestyle habits is a good option that has not been summarized or analyzed.

Objective

To elucidate the relationship between vitiligo and lifestyle factors.

Methods

Four databases (PubMed, Embase, Cochrane, and China National Knowledge Internet) were searched for articles published between 1980 and December 2022. Keywords such as smoking, drinking, exercise, diet, and sleep were used.

Results

Based on the search strategy, 875 relevant studies were retrieved, and 73 were included in this study, of which 41 studies with 8,542 patients with vitiligo were included in the meta-analysis. Vitamin C [mean difference (MD), -0.342; 95% confidence interval (CI), -1.090-0.407; p >0.05), folic acid (MD, -1.463; 95% CI, -7.133-4.208; p >0.05), and selenium (MD, 0.350; 95% CI, -0.687-1.387; p >0.05) levels did not differ between the groups. Vitamin E (MD, -1.408; 95% CI, -2.611--0.206; p <0.05), vitamin B12 (MD, -0.951; 95% CI, -1.672--0.275; p <0.05), copper (MD, -0.719; 95% CI, -1.185--0.252, p <0.005), and zinc (MD, -0.642; 95% CI, -0.731--0.554; p <0.001) levels were lower in the vitiligo group than in the control group. The serum iron level of the vitiligo group was significantly higher than that of the control group (MD, 1.181; 95% CI, 0.390-1.972; p <0.005). Finally, more participants in the vitiligo group smoked and drank alcohol than those in the control group.

Limitations

Most studies are from Eastern countries; thus, extrapolating these results to Western populations is questionable. The significant heterogeneity may be attributed to the different stages, types, duration, center settings, population registries, etc., which seriously impair the validity of the results.

Conclusions

Patients with vitiligo should reduce smoking and alcohol consumption and take appropriate vitamin E, B12, copper, and zinc supplements. However, vitamin C, vitamin D, selenium, iron, and folic acid supplements are unnecessary. Moreover, they should consider sun protection and avoid permanent hair dye use. Patients with vitiligo may experience sleep disturbances and sexual dysfunction, and these patients should seek help from a specialist if necessary.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#recordDetails, identifier CRD42023480757.

Changing human hair fibre colour and shape from the follicle

INTRODUCTION

Natural hair curvature and colour are genetically determined human traits, that we intentionally change by applying thermal and chemical treatments to the fibre. Presently, those cosmetic methodologies act externally and their recurrent use is quite detrimental to hair fibre quality and even to our health.

OBJECTIVES

This work represents a disruptive concept to modify natural hair colour and curvature. We aim to model the fibre phenotype as it is actively produced in the follicle through the topical delivery of specific bioactive molecules to the scalp.

METHODS

Transcriptome differences between curly and straight hairs were identified by microarray. In scalp samples, the most variable transcripts were mapped by in situ hybridization. Then, by using appropriate cellular models, we screened a chemical library of 1200 generic drugs, searching for molecules that could lead to changes in either fibre colour or curvature. A pilot-scale, single-centre, investigator-initiated, prospective, blind, bilateral (split-scalp) placebo-controlled clinical study with the intervention of cosmetics was conducted to obtain a proof of concept (RNEC n.92938).

RESULTS

We found 85 genes transcribed significantly different between curly and straight hair, not previously associated with this human trait. Next, we mapped some of the most variable genes to the inner root sheath of follicles, reinforcing the role of this cell layer in fibre shape moulding. From the drug library screening, we selected 3 and 4 hits as modulators of melanin synthesis and gene transcription, respectively, to be further tested in 33 volunteers. The intentional specific hair change occurred: 8 of 14 volunteers exhibited colour changes, and 16 of 19 volunteers presented curvature modifications, by the end of the study.

CONCLUSION

The promising results obtained are the first step towards future cosmetics, complementary or alternative to current methodologies, taking hair styling to a new level: changing hair from the inside out.

Fabrication of innovative multifunctional dye using MXene nanosheets

The increasing demand for natural and safer alternatives to traditional hair dyes has led to the investigation of nanomaterials as potential candidates for hair coloring applications. MXene nanosheets have emerged as a promising alternative in this context due to their unique optical and electronic properties. In this study, we aimed to evaluate the potential of Ti3C2Tx (Tx = -O, -OH, -F, etc.) MXene nanosheets as a hair dye. MXene nanosheet-based dyes have been demonstrated to exhibit not only coloring capabilities but also additional properties such as antistatic properties, heat dissipation, and electromagnetic wave shielding. Additionally, surface modification of MXene using collagen reduces the surface roughness of hair and upregulates keratinocyte markers KRT5 and KRT14, demonstrating the potential for tuning its physicochemical and biological properties. This conceptual advancement highlights the potential of MXene nanosheets to go beyond simple cosmetic improvements and provide improved comfort and safety by preventing the presence of hazardous ingredients and solvents while providing versatility.

Determination of 11 Kinds of Hair Dyes in Hair-Dyeing Products by Liquid Chromatography-Tandem Mass Spectrometry

Eleven kinds of hair dyes were determined in hair-dyeing products by liquid chromatography-tandem mass spectrometry (MS). The samples were extracted with ultrasound in methanol for 20 min. After centrifugation, the supernatant was diluted with 10% methanol/90% water (v/v). Then, the solution was analyzed by Shim-pack Scepter C18-120 column (100 mm × 2.1 mm, 1.9 μm) plus electrospray ionization-MS/MS. Matrix-matched standard solutions were used to analyze the samples. The limits of detection were from 0.15 to 10 mg/kg, the limits of quantification were from 0.5 to 40 mg/kg and the recovery was from 79.4 to 109.2%. The protocol was selective and accurate and was satisfyingly applied to analyze hair dyes in different kinds of commercial products. 1-Hydroxyethyl-4,5-diaminopyrazole sulfate, hydroxyethyl-p-phenylenediamine sulfate, 2-methyl-5-hydroxyethylaminophenol, 5-amino-6-chloro-o-cresol, 3-nitro-p-hydroxyethylaminophenol and 2-amino-6-chloro-4-nitrophenol were detected in 10 samples with the concentrations between limits of detection and quantification to 9.27 × 104 mg/kg.

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.

A Dual-Signal Sensing for the Visual and Luminescent Detection of p-Phenylenediamine Based on Cerium-Nitrogen-Co-Doped Carbon Dots

Herein, a visual and luminescent dual-mode (colorimetric and fluorometric) method for the detection of P-phenylenediamine (PPD) in hair dye was successfully established based on cerium-nitrogen co-doped carbon dots (Ce, N-CDs) that displayed remarkable luminescence and peroxidase activity. Ce, N-CDs catalyzed H2O2 to produce superoxide anion, which then oxidized the colorless 3,3,5,5-tetramethylbenzidine (TMB) into blue oxidized TMB (oxTMB), capable of quenching the fluorescence through fluorescence resonance energy transfer (FRET) between Ce, N-CDs and oxTMB. The reducing properties of PPD could reduce oxTMB back to TMB, leading to a decrease in the absorption intensity of oxTMB and a fluorescence recovery of Ce, N-CDs. As a result, the quantitative detection of PPD could be achieved by measuring the absorption values of oxTMB and the fluorescence signal of Ce, N-CDs. The detection limits for PPD were calculated as 0.36 µM and 0.10 µM for colorimetry and fluorimetry, respectively. Furthermore, smartphone application (ColorPicker) capable of measuring the RGB value of the color was utilized in the detection system, facilitating on-site quantitative detection. This approach effectively shortens the detection time and simplifies the operation, offering a powerful and convenient tool for real-time monitoring of PPD.

Pre- and postnatal maternal hair dye use and risk of wheeze and asthma in 5-year-old Japanese children: the Kyushu Okinawa Maternal and Child Health Study

The present study investigated the association between pre- and postnatal maternal hair dye use and the risk of wheeze and asthma in Japanese children aged 5 years. Study participants were 1199 mother-child pairs. Information on the variables under study was obtained using repeated questionnaires completed by parents. Prenatal maternal hair dye use was associated with an increased risk of current wheeze and ever doctor-diagnosed asthma; the adjusted odds ratios (ORs) (95% confidence intervals [CIs]) were 1.44 (1.02-2.02) and 1.51 (1.00-2.25), respectively. Postnatal maternal hair dye use was related to the risk of doctor-diagnosed asthma; the adjusted OR (95% CI) was 1.58 (1.03-2.40). Children who were exposed to maternal hair dye use both prenatally and postnatally had an increased risk of childhood current wheeze and ever doctor-diagnosed asthma; the adjusted ORs (95% CIs) were 1.59 (1.03-2.42) and 1.76 (1.06-2.88), respectively. Our findings suggest that perinatal maternal hair dye use is associated with the risk of wheeze and asthma in children.

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.

Mechanisms of impairment in hair and scalp induced by hair dyeing and perming and potential interventions

With the rapid growth of beauty and personal care industries, many hair-relevant products, hair dyes and hair perms in particular, are increasingly prevalent in both women and men, regardless of being young or old as they frequently change hair color or shape to enhance youthfulness and beauty and to follow fashion trends. Hair dyes and perms alter hair color and/or shape by mechanically changing the physical structure and chemical substances of the hair shaft. However, treatment of hair with chemical formulations has been potentially ascribed to adverse outcomes in the hair shaft including structure damage, chemical constituent disorder, and impaired physical properties, although hair cosmetics procedures are intrinsically safe. Nevertheless, the mechanisms of impairment in the hair shaft and scalp induced by hair dyeing and perming remain elusive. Additionally, adverse reactions activated by exposure to specific chemical ingredients including skin irritation, allergic contact dermatitis (ACD), and even cancer risk have been reported clinically, but existing evidence is not consistent enough in the case of human studies. Herein, the review aims to give an overview of hair cosmetics, especially concerning the basic knowledge about various hair dyes and perms, the consequences for hair shafts and the scalp resulting from the application of hair cosmetics mentioned above, mechanisms of hazardous outcomes, and potential desirable interventions to alleviate the impairment.

Considering the risk of a coloring shampoo with the function of gray hair cover cosmetology and skin barrier: A systematic review

Background and Aims

As the number of demanders who want to easily cover gray hair increases, the demand market is rapidly expanding along with the demand for coloring shampoos that can be dyed while shampooing. Among these coloring shampoo ingredients, it is necessary to differentiate products that are safe and harmless to the human body in consideration of hair loss or skin barrier problems caused by trihydroxybenzene (THB) ingredients. The correct selection criteria were presented by examining the problems, effectiveness, and side effects when used in relation to the skin barrier through previous studies by consideration of the ingredients of the coloring shampoo and the skin barrier of the scalp.

Methods

The analysis of this study looked at previous studies through a systematic literature review through related keywords for coloring shampoo. After reviewing 150-200 related prior papers, a total of 39 review papers were finally selected using the PRISMA flow diagram.

Results

It was confirmed through a literature review that the coloring shampoo containing THB, which is harmful to the human body, has a detrimental effect on the scalp-skin barrier.

Conclusion

This study examined the harmfulness of coloring shampoo on the scalp skin barrier. It was confirmed that frequent coloring shampoo procedures can have various harmful effects on the scalp. Therefore, it is important to reduce side effects caused by the use of harmful ingredients and maintain a healthy scalp condition through analysis of sufficient scalp conditions and consultation with experts. In addition, various studies on the standard standards and age for harmful ingredients are suggested.

Analytical method development and dermal absorption of 2-amino-5-nitrophenol (2A5NP), a hair dye ingredient under oxidative condition

Although 2-amino-5-nitrophenol (2A5NP) is one of the ingredients of hair dye, there has been no information on the dermal absorption rate of 2A5NP. 2A5NP is managed at less than 1.5% in Korea and Japan. In this study, analytical methods were developed and validated using high-performance liquid chromatography (HPLC) in various matrices of wash, swab, stratum corneum (SC), skin (dermis + epidermis), and receptor fluid (RF). Validation results were acceptable based on Korea Ministry of Food and Drug Safety (MFDS) guideline. The HPLC analysis showed a good linearity (r2 = 0.9992-0.9999), a high accuracy (93.1-110.2%), and a good precision (1.1-8.1%) in accordance with the validation guideline. Franz diffusion cell was used to determine dermal absorption of 2A5NP using mini pig skin. 2A5NP (1.5%) was applied to skin at 10 μl/cm2. For certain cosmetic ingredients such as hair dye with short exposure time, an interim wash step (after 30 min) was added during the study. After application for 30 min and 24 h, skin was wiped off with swab and SC was collected using tape stripping. RF was sampled at 0, 1, 2, 4, 8, 12, and 24 h. Total dermal absorption rate of 2A5NP (1.5%) was determined to be 13.6 ± 2.9%.

Erythematous Linear Lesion on the Course of Superficial Fibular Nerve After the Topical Application of Black Henna: A Case Report

Henna is commonly used in body arts, where it produces orange-brown color. It is often mixed with chemicals such as para-phenylenediamine (PPD) to fasten the dyeing process and produce a black color. However, PPD has many allergic and toxic effects. We present a case of henna-induced cutaneous neuritis, which is not reported before. A 27-year-old female presented to our hospital, complaining of pain in her left great toe after applying black henna. Upon examination, the proximal nail fold was inflamed, and an erythematous non-palpable tender lesion was noticed on the dorsum of the foot. The lesion had an inverted-Y shape that was confined to the course of the superficial fibular nerve. Cutaneous nerve inflammation was favored after excluding all the anatomical structures in the region. Black henna should be avoided since it contains PPD, which can be absorbed through the skin and affect the underlying cutaneous nerves.

Serum metabolomic profile of hair dye use

The International Agency for Research on Cancer reported that some chemicals in hair dyes are probably carcinogenic to those exposed to them occupationally. Biological mechanisms through which hair dye use may be related to human metabolism and cancer risk are not well-established. We conducted the first serum metabolomic examination comparing hair dye users and nonusers in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Metabolite assays were conducted using ultrahigh performance liquid chromatography-tandem mass spectrometry. The association between metabolite levels and hair dye use was estimated using linear regression, adjusting for age, body mass index, smoking, and multiple comparisons. Among the 1,401 detected metabolites, 11 compounds differed significantly between the two groups, including four amino acids and three xenobiotics. Redox-related glutathione metabolism was heavily represented, with L-cysteinylglycine disulfide showing the strongest association with hair dye (effect size (β) =  -  0.263; FDR adjusted p-value = 0.0311), along with cysteineglutathione disulfide (β =  - 0.685; FDR adjusted p-value = 0.0312). 5alpha-Androstan-3alpha,17beta-diol disulfate was reduced in hair dye users (β =  - 0.492; FDR adjusted p-value = 0.077). Several compounds related to antioxidation/ROS and other pathways differed significantly between hair dye users and nonusers, including metabolites previously associated with prostate cancer. Our findings suggest possible biological mechanisms through which the use of hair dye could be associated with human metabolism and cancer risk.

Adverse reactions to cosmetics reported to the Chongqing adverse drug reaction monitoring centre system in China

BACKGROUND

Cosmetic adverse reactions (CARs) are becoming widespread in China. However, a comprehensive analysis of data is lacking.

OBJECTIVE

To analyse the clinical characteristics of patients with reported adverse reactions to cosmetics in Chongqing, China.

METHODS

Cases with CARs reported to the Chongqing Adverse Drug Reaction Monitoring Centre System from 2017 to 2021 were analysed.

RESULTS

A total of 23 245 cases were identified, of which 94.5% were women. Contact dermatitis (84.3%) was the most common diagnosis of CARs, followed by acne (3.1%). The most frequently reported clinical signs were erythema (70.1%), followed by papules (35.5%). The majority of CARs were reported to be due to ordinary cosmetics (87.9%), of which 81.0% were skin care products and 7.1% were makeup products. Cosmetics with special functions constituted 12.2%, of these, skin whitening (54.0%) and sunscreen (28.0%) products were most frequently reported.

CONCLUSION

Our results suggest that adverse reactions to cosmetics are of concern in China, and dermatologists should actively identify and diagnose CARs. In addition, we should establish a convenient and effective model for collecting, reporting, and evaluating CARs.

A Comprehensive Review of Mammalian Pigmentation: Paving the Way for Innovative Hair Colour-Changing Cosmetics

The natural colour of hair shafts is formed at the bulb of hair follicles, and it is coupled to the hair growth cycle. Three critical processes must happen for efficient pigmentation: (1) melanosome biogenesis in neural crest-derived melanocytes, (2) the biochemical synthesis of melanins (melanogenesis) inside melanosomes, and (3) the transfer of melanin granules to surrounding pre-cortical keratinocytes for their incorporation into nascent hair fibres. All these steps are under complex genetic control. The array of natural hair colour shades are ascribed to polymorphisms in several pigmentary genes. A myriad of factors acting via autocrine, paracrine, and endocrine mechanisms also contributes for hair colour diversity. Given the enormous social and cosmetic importance attributed to hair colour, hair dyeing is today a common practice. Nonetheless, the adverse effects of the long-term usage of such cosmetic procedures demand the development of new methods for colour change. In this context, case reports of hair lightening, darkening and repigmentation as a side-effect of the therapeutic usage of many drugs substantiate the possibility to tune hair colour by interfering with the biology of follicular pigmentary units. By scrutinizing mammalian pigmentation, this review pinpoints key targetable processes for the development of innovative cosmetics that can safely change the hair colour from the inside out.

4-Chloro-orthophenylenediamine alters DNA integrity and affects cell survival: inferences from a computational, biophysical/biochemical, microscopic and cell-based study

The deleterious impact of toxic constituents of hair dyes over the human health has gained immense attention in the recent past. Their oncogenicity, mutagenicity, role in protein modification, impact on cellular metabolism has been documented. There is little information on the mechanism of reactivity of hair dye components with the nucleic acids and its implications. This work, therefore, uses computational, biophysical/biochemical, microscopic and cell-based study to analyze the interaction of monocyclic aromatic amine and a hair dye component, 4-chloro-orthophenylenediamine (4-Cl-OPD) with the DNA, its impact on DNA structure and cell survival. The results suggest that 4-Cl-OPD binds with the DNA in minor groove of the duplex involving three base pairs preferentially the G-C residues, induces strand breaks and makes DNA thermally labile through loss of hydrogen bonding/base unstacking. 4-Cl-OPD causes fragmentation of DNA, reduction in size of the molecule, alters B-DNA conformation and disrupts its secondary structure. The modified DNA gives fragmented appearance, shows broken strands and aggregation in ultra-structural analysis. 4-Cl-OPD induces ROS generation in lymphocytes, increases the comet's average tail length and reduces the viability of lymphocytes. This study forms a base for establishing the direct toxicity of 4-Cl-OPD at the molecular and cellular level through direct production of superoxide radicalCommunicated by Ramaswamy H. Sarma.

Performance of Dye Removal from Single and Binary Component Systems by Adsorption on Composite Hydrogel Beads Derived from Fruits Wastes Entrapped in Natural Polymeric Matrix

The treatment of contaminated water is currently a major concern worldwide. This work was directed towards the preparation of a composite hydrogel by entrapping cherry stones powder on chitosan, which is known as one of the most abundant natural polymers. The synthesized material was characterized by scanning electron microscopy, by Fourier transform infrared spectroscopy, and by the point of zero charge determination. Its ability to remove two azo dyes models (Acid Red 66 and Reactive Black 5) existing in single form and in binary mixture was evaluated. Response Surface Methodology-Central Composite Design was used to optimize three parameters affecting the process while targeting the lowest final contaminant concentrations. The best results were obtained at pH 2, an adsorbent dose of 100 g/L, and a temperature of 30 °C, when more than 90% of the pollutants from the single component systems and more than 70% of those of the binary mixtures were removed from their aqueous solutions. The adsorption process was in accordance with Elovich and pseudo-second-order kinetic models, and closely followed the Freundlich and Temkin equilibrium isotherms. The obtained results led to the conclusion that the prepared hydrogel composite possesses the ability to successfully retain the target molecules and that it can be considered as a viable adsorbent material.

Risk of Carcinogenicity Associated with Synthetic Hair Dyeing Formulations: A Biochemical View on Action Mechanisms, Genetic Variation and Prevention

Article tries to visualize the potential for carcinogenic trigger in humans with a preference for oxidative synthetic of hair dyeing formulations, especially which belong to the category of permanent colours. According to the International Agency for Cancer, hair dyes for personal use are not strictly classified as carcinogen to humans. However, some controversy exists that requires clarification. Some epidemiological studies support the association between the risk of cancer development and personal use of hair dyes (pooled relative risk RR = 1.50. 95% CI: 1.30-1.98). The world-wide sale of hair dyeing cosmetics have exceeded 15 billion dollars by the year 2012 and has maintained an annual growth rate of 8-10%. This raises concerns and need to be addressed. The review article briefly discusses about the different hair dye components based on their chemical nature, permanence, interaction of dye components with different parts of the hair shaft, action mechanisms, health risk assessment, associated challenges and possible alternatives. There appears variability towards the pathological changes incurred in the human system upon the use of synthetic hair formulations. This probably appears due to the presence of interindividual genetic variation of enzymes handling these xenobiotics. The redox mechanism of major hair dye components appears to be involved in the carcinogenic trigger. Most of the hair dye constituents pose serious health issues. However, we do have few better alternatives to prevent the toxicity associated with hair dye constituents without compromising the need of today's fashion statement and expectations of the youth.

Synthesis and In Situ Behavior of 1,4- and 2,5-(13C) Isotopomers of p-Phenylenediamine in Reconstructed Human Epidermis Using High Resolution Magic Angle Spinning NMR

p-Phenylenediamine (PPD) has been classified as a strong skin allergen, but when it comes to toxicological concerns, benzoquinone diamine (BQDI), the primary oxidation derivative of PPD, is frequently considered and was shown to covalently bind nucleophilic residues on model peptides. However, tests in solution are far from providing a reliable model, as the cutaneous metabolism of PPD is not covered. We now report the synthesis of two ¹³C substituted isotopomers of PPD, 1,4-(¹³C)p-phenylenediamine 1 and 2,5-(¹³C)p-phenylenediamine 2, and the investigation of their reactivity in reconstructed human epidermis (RHE) using the high resolution magic angle spinning (HRMAS) NMR technique. RHE samples were first treated with 1 or 2 and incubated for 1 to 48 h. Compared to the control, spectra clearly showed only the signals of 1 or 2 gradually decreasing with time to disappear after 48 h of incubation. However, the culture media of RHE incubated with 1 for 1 and 24 h, respectively, showed the presence of both monoacetylated- and diacetylated-PPD as major products. Therefore, the acetylation reaction catalyzed by N-acetyltransferase (NAT) enzymes appeared to be the main process taking place in RHE. With the aim of increasing the reactivity by oxidation, 1 and 2 were treated with 0.5 equiv of H₂O₂ prior to their application to RHE and incubated for different times. Under these conditions, new peaks having close chemical shifts to those of PPD-cysteine adducts previously observed in solution were detected. Under such oxidative conditions, we were thus able to detect and quantify cysteine adducts in RHE (maximum of 0.2 nmol/mg of RHE at 8 h of incubation) while no reaction with other nucleophilic amino acid residues could be observed.

Impact of two commercially available hair dyes on germination, morpho-physiology, and biochemistry of Cicer arietinum L. and cytotoxicity study on Allium cepa L. root tip

Contamination of agricultural land and surface water by personal care products and pharmaceutical constituents is a potential environmental threat. The active ingredients of personal care products are life-threatening for users. Present work highlighted the efficacy of the different components of two commercially available hair dyes (synthetic and herbal) on germination, morpho-physiological, biochemical parameters of Cicer arietinum, and cytotoxicity study by Allium cepa root tip. Different treatments such as T1 (control), T2 (cream colour rich), T3 (developer) (The ingredients T2 and T3 are from the same hair dye), T4 (an equal mixture of T2 and T3), and T5 (herbal dye) were considered to run this experiment. The results revealed that all the treatments improve germination with respect to control. Moreover, GSI data suggests that T2 showed the highest germination speed and T3 showed the lowest with respect to other treatments. But root lengths are severely affected by the treatments T3 (100% developer of synthetic hair dye), T4 (an equal mixture of T2 (100% cream colour rich) and T3), and T5 (100% herbal hair dye) with respect to control.T2 also showed the highest root tolerance of all treatments other than control. Similarly, one-way ANOVA results revealed that both fresh weight of roots (p ≤ 0.03) and shoots (p ≤ 0.03) are statistically significant among the different treatments. Moreover, both proline and root ion leakage are higher in the treatment T4 and T5 with respect to control, respectively. On the other hand, the cytotoxicity study highlighted that treatments T3 and T4 showed a higher level of aberration and significantly lower mitotic index compared to treatment T5. Therefore, finally, it may be concluded that both individual and combined forms of ingredients of hair dyes are toxic with respect to cell division and overall plant growth and development.

Superoxide anion radical induced phototoxicity of 2,4,5,6-Tetraminopyrimidine sulfate via mitochondrial-mediated apoptosis in human skin keratinocytes at ambient UVR exposure

2,4,5,6-Tetraaminopyrimidine sulfate (TAPS) is worldwide the most commonly used developer in hair dyes. As skin is the major organ, which is directly exposed to these permanent hair dyes, a comprehensive dermal safety assessment is needed. Hereto, we studied the photosensitization potential and mechanism involved in dermal phototoxicity of TAPS exposed to the dark and UVA/UVB/Sunlight by using different in-chemico and mammalian (HaCaT) cells, as test systems. Our experimental outcomes illustrate that TAPS get photodegraded (LC-MS/MS) and specifically generated superoxide anion radical (O₂^•-) under UVA and UVB via type-I photodynamic reaction. The phototoxic potential of TAPS is measured through MTT, NRU, and LDH assays that depicted a significant reduction in cell viability at the concentration of 25 μg/ml and higher. Different cellular stainings (PI uptake, AO/EB, JC-1, NR uptake) suggested the role of mitochondrial-mediated apoptosis. Further, the transcriptomics study revealed upregulation of Apaf-1, Bax, Caspase 3, Caspase 9, Cytochrome c and downregulation of Bcl-2 and Catalase by TAPS treated cells that strengthen our findings. Thus, the above findings suggest that chronic application of TAPS may be hazardous for human skin and promote various skin diseases.

Study of P-Phenylenediamine (PPD) Concentrations after Hair Dye Mixing: A Call for Safety Reassessment

Para-phenylenediamine (PPD) is a chemical that is widely used in hair dyes. Multiple safety and regulatory agencies have categorized PPD as a potent sensitizer. In addition, PPD has carcinogenicity and genotoxicity attributes and, consequently, it is regulated at a maximal concentration of 2.0%. The aim of this study was to test whether the limit for PPD is surplus, and hence whether the consumer may be exposed to unnecessarily PPD levels. Experimentally, the analysis of PPD was performed using HPLC, where method validation and an inter-laboratory comparison test (ILC) were conducted to evaluate method performance. Thirty-three commercial products were analyzed, and five products were chosen to study the unconsumed PPD. Successfully, the implemented method confirmed its suitability and validity for the determination of PPD. For ILC results, PPD levels were 0.97 ± 0.04% and 0.92 ± 0.02%, quantified by our laboratory and an accredited laboratory, respectively. For all products, the initial concentration (T0) of PPD was lower than the regulatory limit. After 45 min, the content of PPD significantly reduced compared to T0. One product showed unconsumed PPD to be as high as 96% following the recommended dyeing time. In conclusion, the existence of high levels of unreacted PPD increases the likelihood of allergic events and elevates the risk of PPD-related chemicals. Collaborative efforts between industries, regulatory bodies, and health-related decision makers are deemed necessary to establish safe concentrations for PPD.

Nanomaterials in hair care and treatment

Hair care and treatment has evolved significantly through the years as new formulations are continuously being explored in an attempt to meet the demand in cosmetic and medicinal fields. While standard hair care procedures include hair washing, aimed at hair cleansing and maintenance, as well as hair dyeing and bleaching formulations for hair embellishment, modern hair treatments are mainly focused on circumventing hair loss conditions, strengthening hair follicle properties and treat hair infestations. In this regard, active compounds (ACs) included in hair cosmetic formulations include a vast array of hair cleansing and hair dye molecules, and typical hair treatments include anti-hair loss ACs (e.g. minoxidil and finasteride) and anti-lice ACs (e.g. permethrin). However, several challenges still persist, as conventional AC formulations exhibit sub-optimal performance and some may present toxicity issues, calling for an improved design of formulations regarding both efficacy and safety. More recently, nano-based strategies encompassing nanomaterials have emerged as promising tailored approaches to improve the performance of ACs incorporated into hair cosmetics and treatment formulations. The interest in using these nanomaterials is based on account of their ability to: (1) increase stability, safety and biocompatibility of ACs; (2) maximize hair affinity, contact and retention, acting as versatile biointerfaces; (3) enable the controlled release of ACs in both hair and scalp, serving as prolonged AC reservoirs; besides offering (4) hair follicle targeting features attending to the possibility of surface tunability. This review covers the breakthrough of nanomaterials for hair cosmetics and hair treatment, focusing on organic nanomaterials (polymer-based and lipid-based nanoparticles) and inorganic nanomaterials (nanosheets, nanotubes and inorganic nanoparticles), as well as their applications, highlighting their potential as innovative multifunctional nanomaterials towards maximized hair care and treatment. STATEMENT OF SIGNIFICANCE: This manuscript is focused on reviewing the nanotechnological strategies investigated for hair care and treatment so far. While conventional formulations exhibit sub-optimal performance and some may present toxicity issues, the selection of improved and suitable nanodelivery systems is of utmost relevance to ensure a proper active ingredient release in both hair and scalp, maximize hair affinity, contact and retention, and provide hair follicle targeting features, warranting stability, efficacy and safety. This innovative manuscript highlights the advantages of nanotechnology-based approaches, particularly as tunable and versatile biointerfaces, and their applications as innovative multifunctional nanomaterials towards maximized hair care and treatment.

Thermostable bacterial laccase for sustainable dyeing using plant phenols

Laccase is regarded as an efficacious eco-friendly enzyme in various industries. Thus, various laccases have been explored to mitigate the environmental effects of conventional industrial processing; however, the prospects of laccase in hair dyeing have not been thoroughly explored to date. On account of the adverse environmental and health-related issues posed by chemical hair dyeing, laccase as a natural alternative in dyeing hair has recently gained attention. In this study, we executed hair dyeing with different colours and shades of hair dyes developed from natural plant phenols, including ferulic acid, gallic acid, catechol, and syringaldehyde, catalysed by a novel thermostable bacterial laccase (LacT) from Brevibacillus agri. The dyed hair was characterised in terms of its colourimetric parameters (L*, a*, and b*), colour strength (K/S), reflectance (R) and colour durability. L* means luminosity and is defined by L* values from 0 (black) to 100 (white). A positive value of a* means red shades and a negative value indicates green shades. A positive value of b* shows yellow shades and a negative value indicates blue shades. Optical microscopy of circular and longitudinal sections of the dyed hair revealed that the laccase-catalysed dyes did not merely stick to the surface; instead, they well-penetrated the hair. Furthermore, the dyeing process did not affect the surface morphology of the dyed hair. The dyed hair also exhibited a desirable range of colour diversity in terms of market-driven demands and showed considerable resistance to fading during shampooing and pH alterations. Post-dyeing, the texture and tensile strength of the dyed hair remained nearly unchanged. Overall, the outcomes suggest that LacT holds high potential to be exploited extensively in the hair dyeing industry as an alternative to chemical hair dyes.

Laccase is regarded as an efficacious eco-friendly enzyme in various industries.

Association between Maternal Exposure to Chemicals during Pregnancy and the Risk of Foetal Death: The Japan Environment and Children's Study

Scarce knowledge is available on the relationship between maternal chemical exposure during pregnancy and foetal deaths. We studied the association of spontaneous abortions and stillbirths with occupational or daily maternal exposure to chemicals commonly used by pregnant women. Data from the Japan Environment and Children’s Study (JECS), a nationwide prospective birth cohort study, were used. The participants of the study were asked about the frequency of their use of gasoline, pesticides, hair dye, and chlorine bleach during the first and the second to third trimesters of pregnancy. We investigated the relationship between the frequency of the use of chemicals and foetal death. Of the 104,065 foetuses, 923 (0.91%) were spontaneous abortions and 379 (0.37%) were stillbirths. Any type of exposure during the first trimester was not significantly associated with spontaneous abortions. Nevertheless, a more than weekly occupational use of hair dye from the first to the second/third trimester was significantly associated with stillbirth. The results of this study suggest that the frequent use of hair dye during pregnancy can have severe adverse effects on the foetus. These findings can help pregnant women, especially hairdressers, refrain from the continuous use of hair dyes.

Association between gestational hair dye use and allergies at 3 years old: the Japan environment and Children's study

BACKGROUND

Hair dye use frequently induces allergic contact dermatitis, and on rare occasions induces immunoglobulin E-mediated immediate urticaria, anaphylaxis, and asthma. The effects of hair dye use during pregnancy on offspring have been studied for carcinogenicity, but not for development of allergies. This study aimed to assess the association between hair dye use during pregnancy and allergic disease in children at 3 years old.

METHODS

Data of 77,303 participants from the Japan Environment and Children's Study, which is a prospective birth cohort recruited from January 2011 to March 2014, were used. We examined the associations between using hair dye during pregnancy and allergic diseases (food allergy, asthma, atopic dermatitis and allergic rhinitis) in children after adjustment for covariates by multivariable logistic regression.

RESULTS

Among mothers who were exposed to hair dye during pregnancy, 50.0% were exposed in hair salons, 21.3% had home use, and 9.5% had occupational exposure. The percentages of doctor-diagnosed allergies at 3 years old were 6.3% for food allergies, 7.7% for asthma, 7.3% for atopic dermatitis, and 4.6% for allergic rhinitis. In univariable analyses, hair dye use at home and occupational exposure was significantly associated with asthma respectively (odds ratio [OR] 1.15, 95% CI 1.07-1.24 for at home; OR 1.18, 95% CI 1.08-1.28 for occupational exposure). Hair dye use at home were significantly associated with doctor-diagnosed allergic rhinitis at 3 years old (OR 1.12, 95% CI 1.02-1.22). After adjustment for covariates, these associations for asthma decreased and were no longer significant (aOR 1.06, 95% CI 0.98-1.14 for at home; aOR 1.09, 95% CI 1.00-1.20 for occupational exposure, p = 0.057), also for allergic rhinitis (aOR 1.07, 95% CI 0.97-1.19). Doctor-diagnosed allergic rhinitis at 3 years old was significantly associated with hair dye use at home in the most frequent use group (aOR for quite often versus never 1.78, 95% CI 1.22-2.60).

CONCLUSION

Both home and occupation use of hair dye during pregnancy showed a trend of increased odds of allergic rhinitis and asthma in offspring at 3 years. However, the only association that reached significance was in frequency of use analyses between the highest frequency of home hair dye users and allergic rhinitis.

Weakening of the Transdermal Effect of p-Phenylenediamine Pigments by the Temperature-Sensitive Poloxamer Sodium Alginate Gel

A temperature-sensitive hair dye was prepared with a poloxamer-sodium alginate mixture. When the hair dye was applied to the hair (< 32 °C), it retained its flow dynamics. The hair dye was able to undergo a phase change and formed a solid as soon as it touched the scalp (32°C), which reduced the transdermal amount of p-phenylenediamine (PPD) and also adverse effects and toxicity. Compared to a conventional hair dye, the temperature-sensitive hair dye achieved a reduction of the transdermal amount of p-phenylenediamine by almost 65% at different concentrations. At the same time, the colouring effect was not significantly reduced. The poloxamer alginate hydrogel can be used as a novel colouring material to reduce the harm of the dye intermediate to the human body when colouring hair.

Exposure to N-monoacetyl-p-phenylenediamine impaired ovarian function in mice

p-Phenylenediamine (PPD) is the main constituent of permanent hair dye and is also widely used in the photographic and rubber industries. PPD and its metabolites have been shown to increase the risk of cancer (especially ovarian cancer); however, their effect on female reproduction is unclear. We investigated the effects of the PPD metabolite N-monoacetyl-PPD (MAPPD) on mouse blastocyst development and ovarian function. Sixty 8-week-old female Kunming mice were administered at 0-, 100-, and 300-mg/kg/day MPPD by gavage for 28 days. KGN (human ovarian granulosa cells) were treated with MAPPD at concentrations of 0, 50, 100, and 300 μg/ml for 48 h. The number of abnormal blastocysts increased on gestation day 3.5 in all treatment groups. Compared with the control group, in MAPPD exposed group, the number of antral follicles decreased, the levels of E₂ and P₄ decreased in ovarian tissue, the serum levels of E₂ , P₄ , luteinizing hormone (LH), and T decreased, and follicle-stimulating hormone (FSH) increased. The expression of FSH receptor (FSHR) and LH receptor (LHR) was significantly downregulated, and the level of oxidative stress was significantly increased. In KGN cells, the level of reactive oxygen species increased in a dose-dependent manner, and the mRNA levels of FSHR, LHR, and aromatase increased. These results suggest that MAPPD inhibits FSH- and LH-induced aromatase activity by causing oxidative stress, which decrease hormone levels, leading to abnormal follicle development. Meanwhile, MAPPD exposure could affect early embryonic development abnormalities by affecting the quality of ovum.

PTCA (1-H-Pyrrole-2,3,5-Tricarboxylic Acid) as a Marker for Oxidative Hair Treatment: Distribution, Gender Aspects, Correlation with EtG and Self-Reports

Hair analysis is an important and reliable resource for the assessment of alcohol or drug abstinence in both clinical and forensic toxicology. Recently, it has been demonstrated that hair oxidative cosmetic treatments lead to the reduction in incorporated xenobiotics in hair, such as ethyl glucuronide (EtG), a marker of alcohol abuse, and the formation of 1-H-pyrrole-2,3,5-tricarboxylic acid (PTCA), a degradation product of melanin. The aim of the present study was to investigate PTCA trends in a large number of samples in order to evaluate the reliability of this biomarker in recognizing previous cosmetic treatment in forensic analyses. Therefore, a single-step extraction followed by an high-performance liquid chromatography--tandem mass spectrometry (HPLC--MS-MS) method was established and validated for the simultaneous determination of EtG and PTCA. This method was applied to 1,219 scalp hair samples from two groups, namely self-reported untreated and in vivo treated hair, exhibiting a concentration range of 6.7 to 440.0 pg/mg for EtG (mean 26.8 pg/mg, median 14.6 pg/mg) and 0.009 to 49.8 ng/mg for PTCA (mean 0.66 ng/mg, median 0.02 ng/mg). The PTCA content was significantly different among the two experimental groups, with the in vivo treated group showing significantly higher levels of PTCA than the untreated group. Finally, an in vitro bleaching was performed and the results confirmed that a strong hair oxidative treatment may negatively affect EtG test results (false negative), whereas the mean PTCA content increased showing statistically significant differences between untreated and in vitro oxidative treated samples. The present study suggests that the determination of PTCA in routine hair analysis procedure could be useful in order to discover previous cosmetic treatment including oxidation.

Allergic contact dermatitis: a significant environmental and occupational skin disease

This review article seeks to provide an overview of allergic contact dermatitis (ACD) as a significant environmental and occupational skin disease, the phases of ACD, its causes from the occupational and environmental perspectives, its detection, the effects of ACD with respect to the social, psychological, occupational, and financial perspectives, and its cure and/or prevention. Human skin is very sensitive and as the largest organ in the body, it is highly prone to direct and indirect contact with the substances from its environment. The skin reacts to these substances (xenobiotics) differently depending on the individual's tolerance level or threshold. Allergic contact dermatitis is a significant environmental and occupational skin disease that should not be ignored in our society because it can affect the quality of life of an affected individual. There are multiple causes of ACD, and these causes of ACD have been discussed from two perspectives: environmental and occupational. The effects of ACD can be psychological, social, financial, and occupational. There is need for more public enlightenment on the effects of ACD as well as a precise understanding that it is not a contagious disease so as to significantly reduce the psychological and social effects of ACD on these patients.

Cocrystal hydrate of Bandrowski's base and clotrimazole: a prospective ingredient for hair dye formulations

When crystallized with the antifungal medication clotrimazole, p-phenylenediamine, the most prominent hair developer used in the hair dye industry today, is oxidized to its trimeric product Bandrowski's base, and forms a cocrystal.

Rhus semialata M. extract ameliorate para-phenylenediamine-induced toxicity in keratinocytes

para-Phenylediamine (PPD), a major component of hair dyeing ingredients, can induce allergenic sensitization and exert mutagenic, tumorigenic and cytotoxic effect. In this study, we determined the cytotoxic effect of PPD on human keratinocytes and evaluated the protective effect of Rhus semialata M. extracts (RSE) on PPD induced cytotoxicity for the first time. We observed that RSE is a strong inhibitory agent against PPD-induced toxicity in human keratinocytes. The results indicated that RSE pretreatment significantly could suppress PPD induced cytotoxic effects, including decrease of cell viability, accumulation in subG1 phase of cells, and relocation of phosphatidylserine on keratinocytes. Also, we found that PPD caused cytotoxicity was associated with mitochondrial membrane potential loss and subsequent activation of caspase and PARP degradation. However, pretreatment of RSE showed preventive activities against PPD induced mitochondrial membrane potential loss and ROS production in keratinocytes. In conclusion, the results of present study suggest that RSE was able to protect the skin from several cytotoxic effects of PPD and could be a meaningful material in many industries using PPD.

Assessment of semi-permanent hair dyes in wash water from beauty salons by liquid chromatography-tandem mass spectrometry-selected reaction monitoring (LC-MS/MS-SRM)

Herein, we present an approach for the analytical determination and quantification of semi-permanent hair dyes in wash water samples released during washing of dyed hair employing a liquid chromatography-tandem mass spectrometry-selected reaction monitoring (LC-MS/MS-SRM) method with electrospray ionization detection. Specifically, Basic Blue 99 (BB 99), Basic Brown 16 (BB 16), Basic Red 76 (BR 76), Basic Yellow 57 (BY 57) and Acid Violet 43 (AV 43) are hair dyes with properties known to be harmful to human health and the environment. The hair dyes are present in commercial formulation and are discharged into the effluents without fully effective treatment. The detection and quantification by the LC-MS/MS technique show a linear relationship for each studied hair dye in the concentration range from 1 to 200 ng mL^-1 in aqueous solution. The limits of detection and quantification were found from 0.66 to 20 ng mL^-1 and from 2.0 to 63 ng mL^-1, respectively, values that are compatible with the level required in wash water analysis. The method was applied in samples collected from 5 successive washings of hair dyed with a commercial formulation using the established procedure. BB 99 and BY 57 dyes have lower fixation on the scalp and hair, showing 866 ng mL^-1 and 145 ng mL^-1 release on the first day of washing, respectively. The accumulation of dye and slow release after washing can lead to future problems for both the environment and living organisms.

Evaluation of the effects of hair colouring products on the oxidative status in rats

Introduction

Permanent hair dyes, oxidant creams, and henna are usually used for cosmetic purposes and sometimes for therapeutic expectations. The effects of these products, which are used to change hair colour and can be absorbed percutaneously on the oxidative status is not known exactly.

Aim

To investigate the effects of these products, which have various contents, on the oxidative status using an in vivo rat model.

Material and methods

The products used for hair colouring were prepared as recommended for human use and applied to the back region of Wistar albino rats. Superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) levels were measured in serum and liver samples of rats. The Kruskal-Wallis test showed significant differences in serum SOD, aspartate aminotranspherase (AST), alanine aminotranspherase (ALT), and liver MDA levels among the study groups.

Results

There were statistically significant positive correlations between hepatic MDA values and AST and ALT values. Hair dyes, oxidant creams, and henna were found to have oxidative and hepatotoxic effects. Surprisingly, comparisons revealed that oxidative effect and hepatic toxicity of the oxidant cream and henna were similar. The oxidant cream was more oxidating and hepatotoxic than the hair dye.

Conclusions

Knowing the facts about these products, which are easily accessible to every individual in society and are considered to be innocent, will prevent possible harm.

Hair dye and risk of skin sensitization induction: a product survey and quantitative risk assessment for para-phenylenediamine (PPD)

BACKGROUND

Para-Phenylenediamine (PPD) is a commonly used dye intermediate in permanent hair dye formulations, and exposure to PPD has been associated with allergic contact dermatitis at certain doses.

PURPOSE

Determine the concentration of PPD in a survey of self-application permanent hair dye products, and perform a quantitative risk assessment to determine the risk of skin sensitization induction following application of these products.

METHODS

Consumer exposure levels (CELs) to PPD following application of hair dye products were estimated using the maximum amount of hair dye that can adhere to the surface area of the scalp, the measured concentration of PPD in the hair dye product, a retention factor, the dermal absorption of PPD, and the surface area of the scalp. CELs were calculated for various exposure scenarios, and were stratified by hair dye shade.

RESULTS

All estimated CELs did not exceed the acceptable exposure level. Specifically, margins of safety ranged from 2.3 to 1534 for black dyes, 2.9 to 5031 for brown dyes, and 26 to 5031 for blonde dyes.

CONCLUSIONS

Findings suggest that use of the evaluated permanent hair dyes, under the evaluated exposure scenarios, would not be expected to induce skin sensitization due to PPD exposure at concentrations ≤0.67%.

Application of cytogenetic model Allium cepa for screening potential cytogenotoxicity of herbal-based hair dyes

Plant models may be useful as test organisms for initial screening of potential toxicity of personal care products. The objective of the present study was to assess the efficacy of the Allium cepa (common onion) test system as a bioanalytical tool for screening potential cytotoxicity and genotoxicity of herbal-based hair dye formulations. Exposure of black hair dye formulations for 48 hours resulted in root growth retardation and mitosis suppression in the root meristems of A. cepa bulbs indicating concentration dependent cytotoxicity. At the 72 hour post exposure, cytotoxic effects on the roots were reduced but not recovered completely signifying prolong toxic action of the hair dyes. The condensed nuclei was the most frequent nuclear abnormality found in the dye exposed root meristematic cells indicating the cell death process. Induction of micronuclei and chromosomal aberrations in the root meristematic cells even at the post exposure stage indicates persistent genotoxicity of the hair dyes which may be attributed to the interactive effects of chemical mixtures present in the commercial hair dye formulations. The results revealed that A. cepa test system is an effective bioanalytical tool for screening cytogenotoxicity of commercial hair dye formulations.

Fast-changing life-styles and ecotoxicity of hair dyes drive the emergence of hidden toxicants threatening environmental sustainability in Asia

The practice of hair dyeing is a rapidly expanding industry on a global scale; however, it has become a major concern for Asian countries because they have been undergoing rapid transformations of their environment and lifestyles. While the socio-economic benefits and impacts of this globalization trend are widely understood, the environmental effects are largely unknown. In particular, commonly available oxidative dyes potentially pose specific environmental risks due to their use of a toxic aromatic amine p-Phenylenediamine (PPD). In investigating the environmental impacts of PPD chemicals, we first provide context to the study by setting out the socio-psychological drivers to industrial expansion in Asian countries along with an overview of research into its effects, to show that its environmental impacts are under-researched. We then investigate the environmental toxicity of PPD by focusing on the role of microbes in metabolizing waste products. Results show that Acinetobacter baumannii EB1 isolated from dye effluent prevents autoxidation of PPD under oxygen-enriched (shaking) or oxygen-deficient (static) conditions representing different environmental settings. Microbes transformed PPD into more toxic metabolites, which then significantly reduced plant growth, thereby having a direct bearing on ecosystem services. Based on the findings, we argue that stricter regulatory controls on hair dye wastewater are necessary, particularly in newly industrialising Asian countries where the expansion of commercial practice is most prevalent.

Investigation on the 2D-Distribution of Metallic Elements after Hair Dyeing

Long-term use of hair dyes has potential effects on metal content in hair. However, little research dissects the specific distribution and composition variations of the metal after dyeing. In this study, we investigated the morphological change and metallic elements content variation after dyeing. The results showed that the concentration of essential metal elements decreased, among which the Ca, K, and Na decreased sharply even above 50%. As for the heavy metal, the most significant observation is that Pb increased almost by five times after dyeing. Besides, it revealed, using scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), that Pb concentrated at the outer layer of the hair. In addition, two-dimensional proton-induced X-ray emission (2D-PIXE) was applied to analyze the distribution of metallic elements along the longitudinal and cross section of the hair. The results showed that Ca and Zn distributed evenly in the hair along the longitudinal and cross section. It is the first time that 2D-PIXE is applied to analyze the metallic distribution in the hair. This method exhibits high sensitivity and can be widely used in the environmental and medical field to analyze the distribution of metallic elements.

Hair dye and chemical straightener use and breast cancer risk in a large US population of black and white women

Many hair products contain endocrine-disrupting compounds and carcinogens potentially relevant to breast cancer. Products used predominately by black women may contain more hormonally-active compounds. In a national prospective cohort study, we examined the association between hair dye and chemical relaxer/straightener use and breast cancer risk by ethnicity. Sister Study participants (n = 46,709), women ages 35-74, were enrolled between 2003 and 2009, and had a sister with breast cancer but were breast cancer-free themselves. Enrollment questionnaires included past 12-month hair product use. Cox proportional hazards models estimated adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the association between hair products and breast cancer; effect measure modification by ethnicity was evaluated. During follow-up (mean = 8.3 years), 2,794 breast cancers were identified. Fifty-five percent of participants reported using permanent dye at enrollment. Permanent dye use was associated with 45% higher breast cancer risk in black women (HR = 1.45, 95% CI: 1.10-1.90), and 7% higher risk in white women (HR = 1.07, 95% CI: 0.99-1.16; heterogeneity p = 0.04). Among all participants, personal straightener use was associated with breast cancer risk (HR = 1.18, 95% CI 0.99-1.41); with higher risk associated with increased frequency (p for trend = 0.02). Nonprofessional application of semipermanent dye (HR = 1.28, 95% CI 1.05-1.56) and straighteners (HR = 1.27, 95% CI 0.99-1.62) to others was associated with breast cancer risk. We observed a higher breast cancer risk associated with any straightener use and personal use of permanent dye, especially among black women. These results suggest that chemicals in hair products may play a role in breast carcinogenesis.

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.

Investigation of the effect of the virtual reality application on experimental pain severity in healthy

OBJECTIVE

This study aimed to investigate the effect of virtual reality application on experimental ischemic pain created with a blood pressure instrument in healthy volunteers.

METHODS

The research sample consisted of 172 volunteer adult students who conformed to the inclusion criteria. These individuals were assigned into an experimental (n=86) and a control group (n=86) by a simple randomization method. All individuals in the experimental and control groups wereexperimentally subjected to pain for two minutes by applying 260 mmHg of pressure 3-4 cm above the antecubital region of the left arm with an aneroid adult-type blood pressure instrument. During the procedure, the volunteers in the experimental group watched virtual reality images, while those in the control group received no intervention. Immediately after the procedure, the pain levels of the individuals in both groups were assessed with a Visual Analog Scale (VAS).

RESULTS

We found that the mean pain score of the individuals in the experimental group was 2.62±1.82, and that of individuals in the control group was 5.75±1.65. Results of the statistical analysis showed a statistically significant difference between the mean pain scores of the individuals in the experimental and control groups (p<0.001).

CONCLUSION

This study found that the use of virtual reality was effective in reducing the level of pain in healthy individuals. This method used a smartphone with widespread availability and ease of transportation, which can be used by health professionals as a non-pharmacological method in the management of pain.

Radon emanation from human hair

Bio-indicator of long time exposure to pollutants, human hair is studied in contaminated areas. The number of studies on background environments remains small, and factors impacting human hair radioactivity in contaminated and background areas remain poorly known. Radon-222, a radioactive noble gas of half-life 3.8 days, is the alpha decay daughter of radium-226 in the uranium-238 chain. Radon emission depends on radium concentration (C_Ra) and probability of decaying radium to liberate radon (i.e., the emanation coefficient E). The radon-222 emanating power (i.e., radon emanation or effective radium-226 concentration, EC_Ra) is measured in the laboratory from human hair of a cohort of 93 individuals living in uranium non-contaminated areas using a high-sensitivity method based on 371 long accumulation sessions. E of human hair is also determined. EC_Ra values from human hair are heterogeneous, ranging from 0.059 ± 0.008 to 3.7 ± 0.1 Bq kg^-1 (mean: 0.484 ± 0.006 Bq kg^-1). We find 2.6 ± 0.1 and 2.5 ± 0.1 times larger values for females than males and for color-treated than natural hair, respectively. By contrast, E is homogeneous (mean: 0.33 ± 0.11; n = 9). Our data suggest a different behavior of accumulation/elimination processes of heavy elements in females and non-negligible radium concentration in hair dye products. Our results demonstrate ²²⁶Ra-²³⁸U disequilibrium in human hair, indicating secondary radium intake, and that EC_Ra mainly depends on C_Ra. Other factors such as age and sampling time are also studied. The impact of factors on EC_Ra from human hair in uranium non-contaminated areas is ordered as follows: (body site?) > sex > hair dyeing > dietary/drinking habits > natural color > time period > geographical location > age. Any human hair-based study should take into consideration these factors. Our method, cost-effective and easy to implement, may be applied to large numbers of samples for large-scale epidemiological studies, and may also be useful for criminal investigations.