Effect of equilibrium pH on the structure and properties of bleach-damaged human hair fibers

Hair proteins are significantly affected by environmental pH. This impact tends to increase with prior hair damage. To understand how pH affects bleached hair properties, we utilized a number of techniques allowing for the determination of hair thermal properties, swelling and water sorption, and dry and wet tensile properties. At pH 5, hair proteins had the best structural integrity, as determined by differential scanning calorimetry and the highest tensile modulus. At pH 10, protein cross-linking density decreased, water content and hair cross-sectional diameter increased. Alkaline treatment, when compared with pH 5, did not reduce intermediate filament conditions (evaluated via enthalpy measurement) nor mechanical property performance in the wet state. In contrast to alkaline-treated hair, bleached hair equilibrated at pH 3 behaved very differently: it contained two different crosslink density zones, was the least stiff in dry and stiffest in wet conditions. Additionally, it absorbed less water and had the lowest diameter because of reduced water binding by protonated carboxyl groups. The pH 3 to 10 did not affect the mechanical strength of bleached hair in dry or wet conditions.     

Relative and combined effects of ethanol and protein deficiency on some hair trace elements

This study was performed in order to analyze the relative and combined effects of ethanol and protein deficiency on hair copper, zinc, manganese, and iron content in four groups of seven animals each which were pair-fed during 8 wk with (1) a nutritionally adequate diet, (2) a 36% (as energy) ethanol-containing isocaloric diet, (3) a 2% protein, isocaloric diet, and (4) a 36% ethanol, 2% protein isocaloric diet, respectively, following the Lieber-DeCarli model, and to analyze the relationship between hair copper, zinc, manganese, and iron content, and the liver and muscle content of these elements. Although there was a trend to higher levels of all the elements analyzed in the the hair of the low-protein fed animals, differences were statistically significant regarding copper and manganese, effects being solely attributable to the low protein diet, not to ethanol. Moreover, hair copper was significantly, inversely related with final weight and weight loss. There were significant relationship between liver zinc and muscle zinc (r=0.57, p=0.002), but not between liver or muscle zinc and hair zinc; no correlations were observed between muscle copper and hair copper, nor between liver manganese and hair manganese. An inverse, statistically significant correlation was observed between liver copper and hair copper (r=−0.39, p<0.05).     

漠河地区养殖的北极狐冬季被毛性状与保温性能的关系

被毛是哺乳动物最主要的特征之一,其保温功能对动物适应寒冷环境意义重大。为了探讨北极狐(Alopex lagopus)在被毛性状上如何适应寒冷的气候条件,对大兴安岭漠河地区人工养殖北极狐的背中部直针毛、上层绒毛、下层绒毛的长度、毛根细度、毛干细度以及毛密度、单个毛束内的毛数量、毛束密度、复合毛囊最大横切面积、1mm2内复合毛囊最大横切面总面积等14个性状因子进行测量分析。结果表明,北极狐绒毛分为上下两层,下层绒毛的长度、毛根细度和毛干细度均小于上层绒毛,上层绒毛长度与直针毛接近,直针毛长度与上层绒毛、下层绒毛长度均不存在显著相关性;毛密度与毛束密度极度正相关(P0.01),但与毛根细度、毛干细度、单个毛束内的毛数量和1mm2内复合毛囊最大横切面总面积不存在显著相关性,且与复合毛囊最大横切面积的相关性较小;复合毛囊最大横切面积受毛根细度、单个毛束内的毛数量和毛束密度的影响较小。北极狐不是通过降低毛细度的方式来增加毛密度以加强保温功能,而是通过改变被毛在皮肤内的分布格局来增加毛密度,以及将有髓质的绒毛分为上下两层来改变被毛空间结构这两种策略提高被毛内静止空气的量以加强保温功能,进而适应高纬度地区的寒冷环境。     

Is there any relationship between decreased AgNOR protein synthesis and human hair loss?

Argyrophilic nucleolar organizing region associated proteins (AgNORs) play roles in cell proliferation and a variety of diseases. We attempted to determine whether decreased NOR protein synthesis causes human hair loss. We studied 21 healthy males who suffered hair loss on the frontal/vertex portion of the head. Hair root cells from normal and hair loss sites were stained for AgNOR. One hundred nuclei per site were evaluated and the AgNOR number and NORa/TNa proportions of individual cells were determined using a computer program. The cells from normal sites had significantly higher AgNOR counts than those from hair loss sites. Also, the cells from the normal sites had significantly higher NORa/TNa than cells from the hair loss sites. In the normal sites, the cells demonstrated more NOR protein synthesis than cells in hair loss sites. Therefore, decreased NOR protein synthesis appears to be related to hair loss in humans.     

亚热带典型树种根毛特征及其与共生真菌的关系

根毛和共生真菌增加了吸收面积,提高了植物获取磷等土壤资源的能力。由于野外原位观测根表微观结构较为困难,吸收细根、根毛、共生真菌如何相互作用并适应土壤资源供应,缺乏相应的数据和理论。该研究以受磷限制的亚热带森林为对象,选取了21种典型树种,定量了根毛存在情况、属性变异,分析了根毛形态特征与共生真菌侵染率、吸收细根功能属性之间的关系,探讨了根表结构对低磷土壤的响应和适应格局。结果表明:1)在亚热带森林根毛不是普遍存在的, 21个树种中仅发现7个树种存有根毛, 4个为丛枝菌根(AM)树种, 3个为外生菌根(ECM)树种。其中,马尾松(Pinus massoniana)根毛出现率最高,为86%;2)菌根类型是理解根-根毛-共生真菌关系的关键,AM树种根毛密度与共生真菌侵染率正相关,但ECM树种根毛直径与共生真菌侵染率负相关; 3) AM树种根毛长度和根毛直径、ECM树种根毛出现率与土壤有效磷含量呈负相关关系。该研究揭示了不同菌根类型树种根毛-共生真菌-根属性的格局及相互作用,为精细理解养分获取策略奠定了基础。     

胰岛素样因子(IGF-I)对绵羊毛囊体外培养的研究

对胰岛素样因子（IGF—Ⅰ）对毛囊形态影响及生长调控机理作了初步研究,分别采用0．1ng/mL、1ng／mL、10ng/mL、100ng/mL浓度梯度和对照组,结果表明10ng/／mL IGF—Ⅰ对毛囊生长具有明显的促生长作用,生长速度为0．26mm/d,对其作毛囊生长长度与培养关数进行回归分析,结果表明：培养前8d毛囊生长长度与培养时间呈明显的正相关（P〈0．05）。该试验仅从细胞水平上对体外培养毛囊生长及形态进行了研究,初步证实了IGF—Ⅰ有刺激毛囊生长正向调节作用。     

Human fine body hair enhances ectoparasite detection

Although we are relatively naked in comparison with other primates, the human body is covered in a layer of fine hair (vellus and terminal hair) at a relatively high follicular density. There are relatively few explanations for the evolutionary maintenance of this type of human hair. Here, we experimentally test the hypothesis that human fine body hair plays a defensive function against ectoparasites (bed bugs). Our results show that fine body hair enhances the detection of ectoparasites through the combined effects of (i) increasing the parasite's search time and (ii) enhancing its detection.     

Elemental anomalies in hair as indicators of endocrinologic pathologies and deficiencies in calcium and bone metabolism

Analytical results obtained by ICP-MS of hair samples from a group of women from Rio de Janeiro city show that abnormal Ca and P concentrations in this compartment can be an indication of pathologies affecting the metabolism of these elements. The study was conducted initially on 900 women (outpatients, >40 years). From this group, approx. 24% showed anomalously high or low Ca concentrations in hair, in some cases correlated to anomalies of other elements. In 144 cases (16%), very high concentrations of Ca (up to 8,285 mg/kg) were measured, frequently correlated with a high concentration of P (up to 4,720 mg/kg), exceeding by far the reference intervals for this age/sex group. Follow-up studies of a few individuals from this group gave first indications that their abnormal hair compositions were related to endocrinologic pathologies affecting calcium/bone metabolism. Very low hair Ca-concentrations were observed in older women (72 cases, age >60 years) and related to senile osteoporosis. Complementary investigations of patients with recognized endocrinologic pathologies (hyperthyroidism, hyper- and hypoparathyroidism) and osteomalacia gave statistical support for the hypothesis that hair concentrations of Ca, P and various other trace elements are influenced characteristically by these diseases. In patients with hyperparathyroidism and hyperthyroidism, both elements showed significant increase in hair, whereas patients with rickets/osteomalacia had only elevated Ca concentrations, together with suspiciously high toxic levels of Cd and various other elements (Fe, Mn, Mg, Sr, Ba). Patients with hypoparathyroidism had significantly decreased Ca and P concentrations in hair. Statistical evaluation of these data by multivariant analysis (MANOVA) using a contrast matrix and by discriminant analysis showed that elemental hair anomalies can be used to diagnose correctly the above-mentioned pathologies, demonstrating the usefulness of hair analysis as a complementary tool for the detection of disturbances in calcium/bone metabolism.     

A modified and cost-effective method for hair cortisol analysis

Hair cortisol may hold potential as a biomarker for assessment of chronic psychological stress. We report a modified and cost-effective method to prepare hair samples for cortisol assay. Hair samples were ground using an inexpensive ball grinder – ULTRA-TURRAX tube drive. Cortisol was extracted from the powder under various defined conditions. The data showed that the optimal conditions for this method include cortisol extraction at room temperature and evaporation using a stream of room air. These findings should allow more widespread research using economical technology to validate the utility of hair cortisol as a biomarker for assessing chronic stress status.     

Determination of copper and zinc levels in human hair

The Cu and Zn levels of both 607 men (1–85 y old) and 649 women (1–92 y old) were determined by atomic absorption spectrometry. Sex does not influence Cu (14.89±0.89 μg/g and 15.26±0.79 μg/g hair for males and females, respectively) and Zn contents (200.97±9.68 μg/g for men and 209.81±9.49 μg/g hair for women). Age influences Cu and Zn concentrations, but only significantly in females: Cu levels decrease over 60 y of age; whereas Zn levels increase significantly from age groups 2–5 to 20–40 years. Hair color influences Cu concentrations in both males and females. In males, white hair containes less Cu than black hair; in females, white hair's Cu levels are significantly lower than those of dark blond, red, light brown, and brown hair. There are no significant differences in Zn concentrations with respect to different hair colors, in either males or females.     

Resting no more: re‐defining telogen,the maintenance stage of the hair growth cycle

The hair follicle (HF) represents a prototypic ectodermal–mesodermal interaction system in which central questions of modern biology can be studied. A unique feature of these stem‐cell‐rich mini‐organs is that they undergo life‐long, cyclic transformations between stages of active regeneration (anagen), apoptotic involution (catagen), and relative proliferative quiescence (telogen). Due to the low proliferation rate and small size of the HF during telogen, this stage was conventionally thought of as a stage of dormancy. However, multiple lines of newly emerging evidence show that HFs during telogen are anything but dormant. Here, we emphasize that telogen is a highly energy‐efficient default state of the mammalian coat, whose function centres around maintenance of the hair fibre and prompt responses to its loss. While actively retaining hair fibres with minimal energy expenditure, telogen HFs can launch a new regeneration cycle in response to a variety of stimuli originating in their autonomous micro‐environment (including its stem cell niche) as well as in their external tissue macro‐environment. Regenerative responses of telogen HFs change as a function of time and can be divided into two sub‐stages: early ‘refractory’ and late ‘competent’ telogen. These changing activities are reflected in hundreds of dynamically regulated genes in telogen skin, possibly aimed at establishing a fast response‐signalling environment to trauma and other disturbances of skin homeostasis. Furthermore, telogen is an interpreter of circadian output in the timing of anagen initiation and the key stage during which the subsequent organ regeneration (anagen) is actively prepared by suppressing molecular brakes on hair growth while activating pro‐regenerative signals. Thus, telogen may serve as an excellent model system for dissecting signalling and cellular interactions that precede the active ‘regenerative mode’ of tissue remodeling. This revised understanding of telogen biology also points to intriguing new therapeutic avenues in the management of common human hair growth disorders.     

敲除非受体酪氨酸激酶c-Abl促进小鼠毛发循环和再生

c-Abl作为非受体酪氨酸激酶家族的成员,参与调节多个组织器官的发育过程,如神经、血管及骨骼等。c-Abl的异常激活也往往导致神经退行性疾病或肿瘤的发生。到目前为止,c-Abl在皮肤和毛发器官中的研究非常少。本研究首先分析了c-Abl基因在皮肤和毛囊中的动态表达情况,发现在毛囊上皮有丰富的表达,然后利用表皮特异性工具小鼠K14-Cre将c-Abl基因在表皮敲除,发现毛囊由静息期向生长期的转换略有加快。小鼠脱毛实验发现,当所有毛囊都从头开始再生时,突变鼠的毛囊起始比对照小鼠更快。这些结果均表明,在表皮敲除c-Abl基因能够导致毛发循环和毛囊再生的加快。进一步的研究发现,以上表型可能是c-Abl通过调节BMP信号通路造成的。我们的工作首次研究了c-Abl基因在皮肤毛囊中的动态表达,揭示了c-Abl通过BMP信号通路调节毛囊再生的机制。     

Dietary vitamin A regulates wingless-related MMTV integration site signaling to alter the hair cycle

Alopecia areata (AA) is an autoimmune hair loss disease caused by a cell-mediated immune attack of the lower portion of the cycling hair follicle. Feeding mice 3–7 times the recommended level of dietary vitamin A accelerated the progression of AA in the graft-induced C3H/HeJ mouse model of AA. In this study, we also found that dietary vitamin A, in a dose dependent manner, activated the hair follicle stem cells (SCs) to induce the development and growth phase of the hair cycle (anagen), which may have made the hair follicle more susceptible to autoimmune attack. Our purpose here is to determine the mechanism by which dietary vitamin A regulates the hair cycle. We found that vitamin A in a dose-dependent manner increased nuclear localized beta-catenin (CTNNB1; a marker of canonical wingless-type Mouse Mammary Tumor Virus integration site family (WNT) signaling) and levels of WNT7A within the hair follicle bulge in these C3H/HeJ mice. These findings suggest that feeding mice high levels of dietary vitamin A increases WNT signaling to activate hair follicle SCs.     

Exosomes derived from uMSCs promote hair regrowth in alopecia areata through accelerating human hair follicular keratinocyte proliferation and migration

Alopecia areata (AA) is a complex genetic disease that results in hair loss due to an autoimmune-mediated attack on the hair follicle. Mesenchymal stem cells (MSCs) have great potential to induce hair regeneration due to their strong secretion ability and multidirectional differentiation. Recent studies have revealed that the therapeutic potential of MSCs comes from their secretion ability, which can produce large amounts of bioactive substances and regulate the key physiological functions of subjects. The secretion products of MSCs, such as vesicles, exosomes, and conditioned media, have significant advantages in preparing of biological products derived from stem cells. Human umbilical cord mesenchymal stem cells (uMSCs) are the best choice for exosome production. uMSCs are obtained from the human umbilical cord. The umbilical cord is easy to obtain, and the efficiency of uMSCs isolation and culture higher than that of obtaining MSCs from bone marrow or adipose tissue. In this study, we investigated the effects of exosomes released from uMSCs in AA mice. In summary, due to easy isolation and cultivation, simple preparation, and convenient storage, it is possible to obtain uMSCs, or uMSCs exosomes for research and clinical treatment.     

Anthropological study of digital and parietal hair of Canadians

Hair exhibits many interesting anthropologic and genetic features such as thickness and cross-sectional morphology. Digital hair, though not adequately studied to date, has potential importance as an anthropologic trait. A digital hair score system was devised in which a number of dorsally haired digital segments (nine segments) of the left fingers, excluding onychogenic segments, was used as a measure of the trait. Thickness and cross-section of the parietal hair of the Ojibwas, a tribe of Canadian Indians, and European Canadians residing in Ontario were compared with those of Japanese and Koreans residing in their respective countries. Segmental distribution of the digital hair in both males and females was similar between Ojibwas and Japanese, Koreans or Formosans, and was significantly larger in British and other European Canadians. Parietal hair of Ojibwas, both males and females, was thinner than that of Japanese, and thicker than that of British Canadians. The parietal hair index was almost equal between Ojibwas and Japanese in both sexes. That of British Canadians was significantly smaller.