Hair cycle

J. Halloy, B. A. Bernard, G. Loussouarn, and A. Goldbeter, Modeling the dynamics of human hair cycles by a follicular automaton. Proc. Natl. Acad. Sci. USA 97, 8328-8333 (2000). 

Hair cycle pattern Mosaic pattern Wave pattern... 

Fig. 12.2. Quantitative measurements of skin. Routine measurements of skin, in late anagen in this figure, include interfollicular epidermal thickness (circled area), hair follicle length (L), dermal thickness (D), hypodermal fat layer thickness (H, normally varies with the hair cycle), and full thickness (FT) from the surface of the stratum corneum to the top of the panniculus carnosus muscle.

Sundberg, J. P., Rourk, M., Boggess, D., Hogan, M. E., Sundberg, B. A. and Bertolino, A. (1997) Angora mouse mutation altered hair cycle, follicular dystrophy, phenotypic maintenance of skin grafts, and changes in keratin expression. Vet Pathol 34, 171-179. 

Muller-Rover, S., Handjiski, B., vanderVeen, C., Eichmuller, S., Foitzik, K., McKay, I. A., et al. (2001) A comprehensive guide for the accurate classification of murine hair follicles in distinct hair cycle stages. /Invest Dermatol 117, 3-15. 

Paus, R. (1998). Principles of hair cycle control. J. Dermatol. 25, 793-802. 

Halloy, J., Bernard, B.A., Loussouam, G., Goldbeter, A. The follicular automaton model effect of stochastidty and of synchronization of hair cycles./. Theor. Biol. 2002, 214 469 179. 

Marzulli and Maibach 1984 Bronaugh et al. 1986). The literature on the effect of age and sex on percutaneous absorption in other species, where more data are available, is confused. For example, it was reported (Banks et al. 1990) that the dermal absorption of certain marker compounds was lower in older rats but that, for different compounds, the reverse was the case (Hall et al. 1992) or indeed that age did not influence dermal absorption in rats (Dick and Scott 1992). Skin permeation in the hairless mouse generally increases with age, corresponding to the single hair cycle, but decreases with a return to the hairless state (Behl et al. 1984a,b). 

Nishikawa et al, 1991). These studies showed a critical dependency of melanocyte development on c-kit at El3.5-14.5, and effects on coat colour were seen following intradermal injection of pregnant mice as early as E10.5. Even in the adult, intradermal injection of the anti-c-k/f antibody when the hair cycle was activated resulted in unpig-mented areas. In addition, studies in and... 

The inhibition or the promotion of protein synthesis in the nucleus that controls the hair cycle and, finally, the metabolic degradation of the steroid and clearing of that species from the activated/inactivated hair cells. 

Several numerical scales of carcinogenicity [20—22] are based on the statistics of cancer induced in small animals, as detected by pathological assay tumours generally arise preferentially at the site of exposure [23,24], However, variables are so numerous — animal species, age, strain, sex, hair-cycle, mitotic cycle, diet, as well as the conditions, general toxicity, and site of administration of the test sample — that indices should only be compared when standard procedures have been applied to large numbers of standardised animals (usually speciHc strains of mice). 

In humans these cycles occur in a relatively random fashion in the follicles at various sites of the body. In certain animals, e.g., the mouse or rabbit, the hair cycle is largely synchronized with regional waves of growth and loss leading to readily discernible areas of hair loss. Other animals are more mosaic (like humans) in their cycles. It is likely that patterns of cycling occur in humans the anterior hair line is one probable candidate. Identifying these minor areas of synchrony in humans has been difficult. 

Kligman AM (1959) The human hair cycle. J Invest Dermatol... 

Additional current pharmacological therapies for hair disorders include a range of antiandrogens that block the intracellular androgen receptors [142], The mechanisms by which all these compounds trigger hair cycle changes are not clear and justify further studies. 

Slominski A et al (1994) Melanogenesis during the anagen-catagen-telogen transformation of the murine hair cycle. J Invest Dermatol 102(6) 862-869... 

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