The Experts below are selected from a list of 123 Experts worldwide ranked by ideXlab platform
Kotaro Yoshimura - One of the best experts on this subject based on the ideXlab platform.
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The Effects of Ischemia and Hyperoxygenation on Hair Growth and Cycle.
Organogenesis, 2020Co-Authors: Harunosuke Kato, Satoshi Itami, Kahori Kinoshita, Natsumi Saito, Koji Kanayama, Masanori Mori, Natsumi Asahi, Ataru Sunaga, Katsutoshi Yoshizato, Kotaro YoshimuraAbstract:Alopecia has several causes, but its relationship with ischemia/hypoxia has not yet been investigated in detail. In this study, we studied the changes of hair follicles induced by ischemia and potential effects of normobaric hyperoxygenation (NBO) on the hair cycle and growth. We found that skin ischemia reduced hair growth rate, hair Shaft Size, and its pigmentation in the anagen phase of mice, which may reflect an aspect of pathophysiology of hair loss (alopecia) and depigmentation (gray/white hairs). Hyperoxygenation increased hair growth rate in organ culture of both human and murine hair follicles. Systemic NBO promoted hair growth in early anagen and mid-anagen, and delayed catagen onset in mice. However, telogen-to-anagen transition was not affected by NBO as far as non-ischemic skin is concerned. The results of this study indicated that the hair follicle is very sensitive to oxygen tension and oxygen tension affects the regulation of hair growth and cycle in vitro and in vivo. It was suggested that systemic NBO can be safely applied for a long period and can be a noninvasive therapeutic approach to alter hair growth and cycle by manipulating the microenvironment of hair follicles.
J. R. Thompson - One of the best experts on this subject based on the ideXlab platform.
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The Size and form of the medulla of human scalp hair is regulated by the hair cycle and cross-sectional Size of the hair Shaft.
The British journal of dermatology, 1999Co-Authors: Peter E. Hutchinson, J. R. ThompsonAbstract:Hairs were sampled from long-haired Caucasian females, and cross-sectional measurements were performed using a rotating profile method at fixed humidity (100%). The effect of the hair cycle on medullation was investigated by examining medulla Size and form along the lengths of anagen and telogen terminal hairs and also from a composite model of the entire medulla, as produced from a full cycle's growth, by amalgamating the results from the anagen and telogen hairs. The effect of hair Shaft cross-sectional Size on medullation has been investigated by controlling any effect of the hair cycle on terminal hairs and by use of the maximal medulla Size in short, fine (vellous) hairs from the same subjects. All terminal hairs were medullated for the majority of their lengths. The presence and Size of the medulla, in terminal hairs, was profoundly affected by the hair cycle. It was largest early in anagen, where the medulla minor axis, major axis and cross-sectional area represented about 26%, 23% and 7% of the corresponding whole hair Shaft parameters (at 100% humidity). The medulla was virtually absent towards the end of anagen. The shape of the medulla cross-section was less elliptical than that of the whole hair Shaft and was close to circular. There was no significant change in medulla shape through anagen. The form of the medulla was also affected by the hair cycle; approximately, it was continuous for the first 50% of anagen, discontinuous for the next 25% and virtually absent or absent for the final 25%. The maximal Size of the medulla, as occurred in early anagen, was markedly associated with the cross-sectional Size of the whole hair Shaft, both within terminal hairs and between all scalp hairs. The medulla was large in terminal hairs and small or absent in very small hairs. The proportion of the whole hair Shaft occupied by the medulla increased with increase in hair Size and reached a maximum in terminal hairs, in which the medulla minor axis represented about 30% of the whole hair Shaft minor axis. Furthermore, this proportion was constant in the terminal hairs and was not related to whole hair Shaft Size. Such maximal proportional medullation might represent a defining feature of terminal hairs. Variation in Size of the medulla is not the cause of the previously reported cycle-dependent change in cross-sectional Size of the whole hair Shaft of terminal hairs.
Rox R Anderson - One of the best experts on this subject based on the ideXlab platform.
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reduction of regrowing hair Shaft Size and pigmentation after ruby and diode laser treatment
Archives of Dermatological Research, 2000Co-Authors: Taiyuan D Lin, Christine C Dierickx, Valeria B Campos, William A Farinelli, J Rosenthal, Rox R AndersonAbstract:Laser pulses which selectively damage pigmented hair follicles are a useful treatment for hypertrichosis. Clinically, regrowing hairs are often thinner and lighter after treatment. In this study, hair Shaft diameter and optical transmission (700 nm) were measured before and after ruby (694 nm) and diode (800 nm) laser irradiation. Hair was collected from 47 and 41 subjects treated with ruby (0.3 ms and 3 ms) and diode (10-20 ms) lasers, respectively. Responders were defined as subjects with significant long-term hair loss as determined by hair counts at 9 and/or 12 months after treatment. In ruby laser responders (34/47), regrowing hairs were significantly both thinner (decreased diameter) and lighter (increased transmission). In nonresponders (13/47), regrowing hairs were lighter, but not thinner. The regrowing hair Shaft absorption coefficient (as calculated assuming Beer's law) was significantly decreased by 0.3 ms ruby laser treatment, but was not changed by 3 ms ruby laser or diode laser treatment. After diode laser treatment, 38 of the 41 subjects were responders and regrowing hairs were both thinner and lighter. These results show that laser treatments can affect structural recovery (Size of hair), follicular pigmentation (hair absorption coefficient), or both. Regrowth of thinner hair (decreased Shaft diameter) occurs in conjunction with actual loss of hair. After long pulses (3 ms ruby; diode), regrowing hair was thinner and also lighter to an extent related to the decrease in hair diameter. In contrast, short ruby laser pulses (0.3 ms) appeared to be capable of inhibiting follicular pigmentation per se, in addition to affecting the hair diameter. This may account for the complete regrowth of lighter hair in nonresponders treated with 0.3 ms pulses. Laser-induced reduction in hair diameter and/or pigmentation are both long-term responses which confer cosmetic benefits in addition to actual hair loss.
Harunosuke Kato - One of the best experts on this subject based on the ideXlab platform.
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The Effects of Ischemia and Hyperoxygenation on Hair Growth and Cycle.
Organogenesis, 2020Co-Authors: Harunosuke Kato, Satoshi Itami, Kahori Kinoshita, Natsumi Saito, Koji Kanayama, Masanori Mori, Natsumi Asahi, Ataru Sunaga, Katsutoshi Yoshizato, Kotaro YoshimuraAbstract:Alopecia has several causes, but its relationship with ischemia/hypoxia has not yet been investigated in detail. In this study, we studied the changes of hair follicles induced by ischemia and potential effects of normobaric hyperoxygenation (NBO) on the hair cycle and growth. We found that skin ischemia reduced hair growth rate, hair Shaft Size, and its pigmentation in the anagen phase of mice, which may reflect an aspect of pathophysiology of hair loss (alopecia) and depigmentation (gray/white hairs). Hyperoxygenation increased hair growth rate in organ culture of both human and murine hair follicles. Systemic NBO promoted hair growth in early anagen and mid-anagen, and delayed catagen onset in mice. However, telogen-to-anagen transition was not affected by NBO as far as non-ischemic skin is concerned. The results of this study indicated that the hair follicle is very sensitive to oxygen tension and oxygen tension affects the regulation of hair growth and cycle in vitro and in vivo. It was suggested that systemic NBO can be safely applied for a long period and can be a noninvasive therapeutic approach to alter hair growth and cycle by manipulating the microenvironment of hair follicles.
Peter E. Hutchinson - One of the best experts on this subject based on the ideXlab platform.
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The Size and form of the medulla of human scalp hair is regulated by the hair cycle and cross-sectional Size of the hair Shaft.
The British journal of dermatology, 1999Co-Authors: Peter E. Hutchinson, J. R. ThompsonAbstract:Hairs were sampled from long-haired Caucasian females, and cross-sectional measurements were performed using a rotating profile method at fixed humidity (100%). The effect of the hair cycle on medullation was investigated by examining medulla Size and form along the lengths of anagen and telogen terminal hairs and also from a composite model of the entire medulla, as produced from a full cycle's growth, by amalgamating the results from the anagen and telogen hairs. The effect of hair Shaft cross-sectional Size on medullation has been investigated by controlling any effect of the hair cycle on terminal hairs and by use of the maximal medulla Size in short, fine (vellous) hairs from the same subjects. All terminal hairs were medullated for the majority of their lengths. The presence and Size of the medulla, in terminal hairs, was profoundly affected by the hair cycle. It was largest early in anagen, where the medulla minor axis, major axis and cross-sectional area represented about 26%, 23% and 7% of the corresponding whole hair Shaft parameters (at 100% humidity). The medulla was virtually absent towards the end of anagen. The shape of the medulla cross-section was less elliptical than that of the whole hair Shaft and was close to circular. There was no significant change in medulla shape through anagen. The form of the medulla was also affected by the hair cycle; approximately, it was continuous for the first 50% of anagen, discontinuous for the next 25% and virtually absent or absent for the final 25%. The maximal Size of the medulla, as occurred in early anagen, was markedly associated with the cross-sectional Size of the whole hair Shaft, both within terminal hairs and between all scalp hairs. The medulla was large in terminal hairs and small or absent in very small hairs. The proportion of the whole hair Shaft occupied by the medulla increased with increase in hair Size and reached a maximum in terminal hairs, in which the medulla minor axis represented about 30% of the whole hair Shaft minor axis. Furthermore, this proportion was constant in the terminal hairs and was not related to whole hair Shaft Size. Such maximal proportional medullation might represent a defining feature of terminal hairs. Variation in Size of the medulla is not the cause of the previously reported cycle-dependent change in cross-sectional Size of the whole hair Shaft of terminal hairs.