Electron microscopic observations of human hair medulla

Wagner, R; Kiyohara, Pedro Kunihiko; Silveira, Marina; Joekes, Inés

doi:10.1111/j.1365-2818.2007.01747.x

Cited by 52 publications

(19 citation statements)

References 31 publications

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“…A medulla may appear opaque or translucent, but the microscopical appearance is primarily a function of whether the mounting media penetrated the air‐filled structure (Palenik, ). Confusion about this aspect of microscopical analysis has led to inferences that human hairs have no air‐filled spaces (Schlake, ), which is not always accurate (Banerjee, ; De Cássia Comis Wagner, Kiyohara, Silveira, & Joekes, ; Kshirsagar, Singh, & Fulari, ; Palenik, ). When a medulla is present in human hairs, it has similar air‐filled vacuoles as other mammalian hairs, but the amorphous appearance and variable nature within hairs from the same individual complicates analysis.…”

Section: Hair Morphology Pigmentation and Developmentmentioning

confidence: 99%

The biology of human hair: A multidisciplinary review

Koch

Tridico²,

Bernard

et al. 2019

American J Hum Biol

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In the last century, human scalp hair morphology has been studied from multiple, and sometimes mutually exclusive, perspectives by anthropologists, biologists, geneticists, forensic scientists, and cosmetic scientists. Here, we review and synthesize historical and current research on hair to better understand the scientific basis and biological implications of hair microstructure and morphology. We revisit the origins of existing nomenclature regarding hair morphology and classifications, discuss the currently recognized limitations to hair analysis within the varied scientific disciplines studying hair, point out aspects of hair biology that remain unknown, and the great potential for integrating these diverse perspectives and expertise in future scientific investigations, while highlighting the benefits of combining nondestructive microscopical analysis with chemical and genomic analyses for explicating hair biology. Further, we propose consensus terminology for root growth stages through descriptions and images that will aid in the morphological and microscopical analysis of human scalp hair, thereby reducing confusion and the promulgation of inaccurate information that is presently in the literature.

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Section: Hair Morphology Pigmentation and Developmentmentioning

confidence: 99%

The biology of human hair: A multidisciplinary review

Koch

Tridico²,

Bernard

et al. 2019

American J Hum Biol

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“…Hair concentrations of heavy metals like arsenic, lead, cadmium and mercury, were correlated with their presence in the internal organs, blood and urine (Robbins, 2012). TEM is an essential tool to assess the homogeneity of a sample and study biological systems at near-atomic-level resolution (Wagner et al, 2007;Sato et al, 2013;Kinsler et al, 2013;Smentkowski, 2014). SAXS is a powerful method providing detailed micro-to nanoscale structural and physical information (the specific inner surface, surface to volume ratio, or lattice type and dimensions) for a variety of systems (Schnablegger & Singh, 2013).…”

mentioning

confidence: 99%

New insights into human hair: SAXS, SEM, TEM and EDX for Alopecia Areata investigations

Coroabă¹,

Chiriac

Săcărescu³

et al. 2020

PeerJ

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Background Alopecia areata (AA) is a T-cell-mediated autoimmune disease and affects up to 2% of the population. There is a need for a more profound and rigorous understanding of the structure and composition of human hair affected by AA in order to manage this disease. The aim of this article is to understand the effects of AA on the structure and composition of human hair. Methods Several physico-chemical investigation methods, such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray Spectroscopy (EDX), and microbeam Small Angle X-ray Scattering (SAXS), were used to analyze human hair samples obtained from healthy donors and patients with AA. Results SEM revealed more severe hair surface defects for the white regrown hair (W-AA) samples. TEM showed the presence of air-like vesicles located in the endocuticle of regrown hair. Analysis of ultrathin sections of W-AA showed the existence of empty vesicles and smaller melanin granules compared to control samples. SAXS demonstrated that unaffected hair of patients with AA (B-AA) and W-AA melanin aggregates are different in their sizes and shapes compared to the control samples. EDX data showed that W-AA elemental composition was significantly different from the other sample groups. Our study showcases promising non-invasive techniques for a better and more accurate understanding of changes in the internal structure and composition of hair affected by AA.

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“…The cortex is composed of organized microfibrils made of alpha-helical keratin embedded and cross-linked with globular proteins in an amorphous matrix [ 34 , 35 ]. The medulla is important for hair strength in coarse hair [ 36 ], although there are more airspaces in the medulla than the cortex [ 37 ]. After treatment with the ash extract, the grey hair showed extended stretching with some alterations in lipid esters (cuticle), alpha-helices (cuticle) and anti-parallel beta-strands (cuticle), suggesting alkaline effects on alpha-beta transition of the hair proteins.…”

Section: Discussionmentioning

confidence: 99%

Eucalyptus ash alters secondary protein conformation of human grey hair and facilitates anthocyanin dyeing

et al. 2018

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Wood ashes infused with water have been traditionally used as hair cosmetics, but little or no research has examined the effects of ash on human hair. This study investigated the effect of eucalyptus ash on the structure and morphology of excised human grey hair and its potential use as a pretreatment in natural hair dyeing using anthocyanins extracted from purple cops of Zea mays. Tensile characteristics and surface morphology of ash-pretreated hair was monitored by texture analysis, scanning electron microscopy and atomic force microscopy. The biochemical characteristics of ash-treated hair were analyzed by synchrotron radiation-FTIR and sulfur K-edge X-ray absorption near edge. Dyeing with anthocyanins was analyzed by Lab color scale and adsorption of anthocyanins. Ash-treated hair was elastically and plastically deformed with microscopic alterations to the ridges of the cuticle cells, similar to ammonia-treated hair. The ash extract significantly changed the relative proportion of alpha-helices in the cuticle and cortex layers (p < 0.05), but did not affect the interaction of S-bonds with neighboring atoms (p > 0.05). Ash-treated hair showed significantly enhanced adsorption of anthocyanins (p < 0.05) which changed the color of the grey hair. The alteration of secondary proteins in the cuticle and cortex layers of the grey hair by ash extract pre-treatment, enhanced anthocyanin adsorption. The eucalyptus ash could potentially be useful as a natural hair dyeing pre-treatment.

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Electron microscopic observations of human hair medulla

Cited by 52 publications

References 31 publications

The biology of human hair: A multidisciplinary review

The biology of human hair: A multidisciplinary review

New insights into human hair: SAXS, SEM, TEM and EDX for Alopecia Areata investigations

Eucalyptus ash alters secondary protein conformation of human grey hair and facilitates anthocyanin dyeing

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