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At least 19 recordsLinked to original sources
PubMed1978

Exploratory skin penetration findings relating to the use of lead acetate hair dyes. Hair as a test tissue for monitoring uptake of systemic lead.

Two experiments were conducted. In the first, 9 adult male subjects applied a marketed hair dye containing 2% lead acetate according to prescribed directions daily for a period of 90 days. Scalp, axillary and pubic hair were monitored for lead content before and at the end of the test period. Scalp hair analyses were used to confirm application of the hair dye; axillary and pubic hair were analyzed as biologic indicators of systemic lead absorption, i.e., metabolic incorporation of lead in hair growing at sites different from the dyed site. The axillary and pubic hair lead levels ranged from less than 6 to 41 ppm at the start and rose to 27 to 466 ppm at the conclusion of the experiment. Using 80 ppm hair lead as a measure of significant systemic absorption, 7 of 9 subjects showed this effect according to uptake by axillary hair and 4 of 9 according to pubic hair uptake. In the second experiment, blood and hair lead levels and blood erythroporphyrin were measured in 11 children from a pica clinic. Blood lead and hair lead levels were significantly correlated, i.e., r = +0.84. A regression formula was constructed relating these two parameters and blood lead values were predicted for the data of experiment 1, using observed hair lead values. The technique has important limitations; nevertheless, within these limitations, 1 of 9 subjects might be expected to have sustained an elevated blood lead level, i.e., in excess of 50 microgram/100 ml. It therefore appears that in the use of lead acetate hair dyes, some lead is absorbed systemically from the scalp.

Adult↗
PubMed2026

Efficacy and Safety of Low-Molecular-Weight Collagen Peptide GT for Improving Hair Condition in Individuals with Damaged Hair: A Randomized, Double-Blind, Placebo-Controlled Trial.

Addressing hair damage is essential for maintaining overall hair and scalp health. Previous studies have suggested that low-molecular-weight collagen peptides may support hair follicle biology through regulation of extracellular matrix homeostasis and cellular signaling pathways. In addition, recent preclinical studies have demonstrated that low-molecular-weight fish collagen peptides promote hair regrowth through activation of proliferative signaling and suppression of inhibitory pathways. However, their clinical efficacy in improving hair damage has not been clearly established. In this study, the efficacy and safety of low-molecular-weight collagen peptide GT (LMWCP GT) were evaluated in Korean adults with damaged hair. In a randomized, placebo-controlled trial, individuals aged 19∼60 years without alopecia but with mild to moderate hair damage received LMWCP GT (3 g/day) for 24 weeks. Compared with placebo, the treatment group demonstrated significant improvements in hair gloss, as measured using a gloss meter (SAMBA) and scanning electron microscopy, as well as in hair elasticity, assessed by tensile strength and hair diameter. Subjective evaluations further indicated improvements in overall hair condition, including gloss, elasticity, thickness, texture, fullness, and appearance. In addition, scalp elasticity was significantly increased in the treatment group. No treatment-related adverse events were observed. These findings indicate that daily supplementation with LMWCP GT (3 g/day) for 24 weeks is safe and effective in improving overall hair condition in individuals with damaged hair without alopecia.

Antioxidants↗
PubMed1978

Woolly hair nevus. Two case reports and a discussion of unruly hair forms.

Woolly hair is very curly hair that is characteristically unruly and will not form naturally into locks. Woolly hair nevus first appears when the scalp hair begins to grow. It is seen as a patch of unruly, very curly hair, arising in a field of otherwise unremarkable scalp hair. Woolly hair can also be seen as a hereditary trait involving the entire scalp and in acquired forms. It may be distinguished from two other types of unruly hair, pili torti and spun glass hair.

Adult↗
PubMedDate not supplied

Studies on the frequencies of PGM1, PGM3 and Es-D types from hair roots in Japanese subjects and the determination of these types from old hair roots.

The frequencies in Japanese subjects are reported of hair roots type PGM1, PGM3, and Es-D, and the determination of these types from old hair roots. The gene frequencies were: PGM11, 0.762; PGM21, 0.230; PGM 71, 0.008; PGM13, 0.621; PGM23, 0.379; Es-D1, 0.625; and Es-D2, 0.375. The old hair roots were analysed after storage at 25 degrees C, 4 degrees C and -80 degrees C; the enzyme activities were detected and typed at 25 degrees C within PGM1 10 days, PGM3 4 days, and Es-D 4 days.

Carboxylic Ester Hydrolases↗
PubMed1978

Hair as a biopsy material. V. Hair metal as an index of hepatic metal in rats: copper and zinc.

Hair copper in 500 day-old adult rats was found to correlate directly with copper in whole liver (P less than 0.001) and the subcellular liver nuclear (P less than 0.022), and cytosol fractions (P less than 0.001). An inverse correlation was found between copper in liver microsomes and plasma cholesterol (P less than 0.044). Similar data analysis for zinc showed no significant correlations (P greater than 0.05). The determination of copper in hair may be useful for assessing total liver copper content in human beings. Copper in liver microsomes may participate in the control of plasma cholesterol.

Animals↗
PubMed1976

Hair.

The psychologic importance of hair to man is in inverse ratio to its physical function. Except for scalp hair and desultory areas of sexual hair, most of man's hair follicles are vestigial. Three problems of hair growth remain to be solved: (1) how the intermittent activity of hair follicles in both animals and man is controlled; (2) how the male hormone alters the hair cycle in human skin; and (3) why larger hairs are produced by testosterone in some areas of the body when in some individuals the hair follicles in the scalp regress. Studies in which skin grafts from rats of different ages were exchanged showed that hair follicles are innately programmed but can be slowly influenced by systemic factors. Steroid hormones, especially estrogens, slow down the moult cycle whereas thyroid hormones accelerate it. What establishes the innate rhythm remains problematical. The fact that plucking out the club hair initiates activity in resting follicles has been explained by the hypothesis that the mitotic inhibitor which accumulates during anagen is normally used up or dispersed during telogen or by wounding. However, contrary to this theory, follicular activity is not prolonged by epilation during anagen. Moreover, if rats are epilated within one or two days of eruption, only club hairs are removed since forceps cannot grasp the tips of the new hairs. Such epilation does not affect the anagen in progress, but remarkedly enough the subsequent resting phase is shortened. Both sexual hair and male-pattern baldness depend on androgenic hormones. Target organs of testosterone convert the hormone to active metabolites, chiefly 5alpha-dihydrotestosterone. In skin, however, 5alpha-dihydrotestosterone may not be the only active tissue androgen. The major metabolite of testosterone incubated with hair roots in androstenedione, and hirsute women without other obvious endocrine abnormality sometimes excrete high levels of androstanediol. Both steroids stimulated the sebaceous glands of hypophysectomized-castrated rats, which, however, showed only a limited response to testosterone. The androgenic steroids, the enzymes that convert them to their active metabolites, and the proteins that bind them are undoubtedly very important to the problems of the growth of sexual hair and male-pattern baldness.

Alopecia↗
PubMed1977

Regional specialization of the hair cell plasmalemma in the organ of corti.

Nonjunctional and nonsynaptic membranes of hair cells in the chinchilla organ of Corti were examined using the freeze-fracture technique. Cytoplasmic leaflets of the apical membranes of hair cells have particles, 6-12 nm in diameter, but many more particles are found on apical membranes of outer hair cells than on inner hair cells. Cytoplasmic leaflets of the lateral membranes of outer hair cells are covered with large particles, but the corresponding regions of the inner hair cell membrane have fewer particles and these are small or medium-sized. Two types of particle aggregate also distinguish this region of the inner hair cell. The first consists of patches of particles closely spaced in rectilinear arrays. The second consists of parallel strands of widely spaced large particles similar in size, but not in distribution, to the large particles on the lateral membranes of the outer hair cells. The basal membrane of outer hair cells is distinguished from that of inner hair cells by plaques consisting of cross-hatched incisures in the external membrane leaflet. While the significance of these anatomical features is not yet apparent, they give the hair cell plasmalemma a richness or regional specialization found in few other cells and suggest that there are important functional differences between inner and outer hair cells.

Animals↗
PubMed2026

The circadian clock proteins PRR modulate root hair development via the RHD6/RSL module in Arabidopsis.

Root hairs, derived from trichoblasts, are critical for plant growth and environmental adaptation. Although environmental cues are known to influence root hair development, how endogenous timing systems such as the circadian clock integrate into the core transcriptional network governing root hair formation remains unclear. Here, we show that the circadian clock-associated protein PSEUDO-RESPONSE REGULATOR5 (PRR5) physically interacts with ROOT HAIR DEFECTIVE6 (RHD6) and RHD6 LIKE1 (RSL1), two basic helix-loop-helix transcription factors essential for root hair initiation. Genetic analyses suggest that PRR proteins contribute to root hair development under long-day conditions in Arabidopsis thaliana. Simultaneous disruption of PRR5, PRR7, and PRR9 results in defective root hairs, whereas PRR5 overexpression markedly increases root hair density and length. Transcriptomic and RT-qPCR analyses reveal that PRRs enhance the expression of RHD6, RSL1, and multiple downstream root hair-responsive genes, while modulating their temporal expression patterns. Furthermore, PRR5-mediated root hair promotion requires RHD6/RSL1, and PRR proteins enhance RHD6-dependent activation of the RSL4 promoter. PRRs also contribute to root hair development under phosphate-deficient and salt-stress conditions. Together, these findings establish a molecular framework in which PRR proteins regulate the RHD6/RSL network to coordinate root hair development and environmental responses.

Arabidopsis↗