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The British Journal of Radiology May 2012Disorders of the scalp often result in severe cosmetic interference with quality of life, creating the need for optimal medical surveillance. We tested the latest... (Review)
Review
Disorders of the scalp often result in severe cosmetic interference with quality of life, creating the need for optimal medical surveillance. We tested the latest generation of ultrasound machines in patients with scalp pathology and prepared a cross-sectional library encompassing a wide assortment of conditions. Normative data on the sonographic anatomy of scalp and human hair, and important methodological considerations, are also included.
Topics: Carcinoma, Squamous Cell; Eyelashes; Female; Hair; Head and Neck Neoplasms; Humans; Male; Scalp; Scalp Dermatoses; Skin Neoplasms; Ultrasonography, Doppler, Color
PubMed: 22253348
DOI: 10.1259/bjr/22636640 -
Seminars in Cell & Developmental Biology Oct 2012Hair follicles (HFs) is an appendage from the vertebrate skin epithelium, and is critical for environmental sensing, animal appearance, and body heat maintenance. HFs... (Review)
Review
Hair follicles (HFs) is an appendage from the vertebrate skin epithelium, and is critical for environmental sensing, animal appearance, and body heat maintenance. HFs arise from the embryonic ectoderm and regenerate cyclically during adult life. Distinct morphological and functional stages from development through homeostasis have been extensively studied for the past decades to dissect the critical molecular mechanisms. Accumulating work suggests that different signaling cascades, such as Wnt, Bmp, Shh, and Notch, together with specific combinations of transcription factors are at work at different stages. Here we provide a comprehensive review of mouse genetics studies, which include lineage tracing along with knockout and over-expression of core genes from key signaling pathways, to paint an updated view of the molecular regulatory network that govern each stage of hair follicle development and adult cycling.
Topics: Animals; Cell Cycle; Cell Differentiation; Hair Follicle; Homeostasis; Humans; Signal Transduction
PubMed: 22939761
DOI: 10.1016/j.semcdb.2012.08.003 -
Advances in Clinical and Experimental... Sep 2017Due to a growing interest in developmental disorders, and in the long-term skin appendage diseases, both in the cosmetic industry and among specialists in dermatology...
BACKGROUND
Due to a growing interest in developmental disorders, and in the long-term skin appendage diseases, both in the cosmetic industry and among specialists in dermatology (broadly defined), there is an increasing number of papers on hair development. The publications by the present team of authors are part of this trend.
OBJECTIVES
The aim of the study was to describe the topography and typology of skin pilosity patterns in human fetuses.
MATERIAL AND METHODS
A total of 278 fetuses (141 male and 137 female) were qualified for the study. The gestational age ranged from 69 to 226 days after conception. All fetuses were taken from a local collection.
RESULTS
The study revealed that the first single hairs occur on the posterior wall of the trunk in the 17th week of fetal life, and on the anterior wall between the 18th and 19th week. It was found that in human fetuses lanugo appears statistically significantly later on the skin of the anterior of the trunk than on its posterior. The difference in absolute time is almost 2 weeks of fetal life. No other differences were found in the development cycle of lanugo on the anterior and posterior walls of the trunk. A full pattern was first observed on the posterior wall of the trunk in a fetus in the 19th week, and on the anterior wall in the 21st week. It was found that the process of lanugo development was completed on the posterior wall in the 23rd week, and on the surface of the abdomen in the 26th week.
CONCLUSIONS
The lanugo developmental cycle, consisting in the appearance of the first single hairs, then partial hair and subsequently the formation of final patterns, is the same on both walls of the trunk.
Topics: Female; Gestational Age; Hair; Humans; Infant, Newborn; Male; Morphogenesis; Skin; Torso
PubMed: 29068598
DOI: 10.17219/acem/61440 -
Actas Dermo-sifiliograficas 2017
Topics: Dermatologic Surgical Procedures; Dermatology; Hair; Humans
PubMed: 28668139
DOI: 10.1016/j.ad.2017.06.001 -
Die Naturwissenschaften Apr 2008In all higher nonhuman primates, species survival depends upon safe carrying of infants clinging to body hair of adults. In this work, measurements of mechanical... (Review)
Review
In all higher nonhuman primates, species survival depends upon safe carrying of infants clinging to body hair of adults. In this work, measurements of mechanical properties of ape hair (gibbon, orangutan, and gorilla) are presented, focusing on constraints for safe infant carrying. Results of hair tensile properties are shown to be species-dependent. Analysis of the mechanics of the mounting position, typical of heavier infant carrying among African apes, shows that both clinging and friction are necessary to carry heavy infants. As a consequence, a required relationship between infant weight, hair-hair friction coefficient, and body angle exists. The hair-hair friction coefficient is measured using natural ape skin samples, and dependence on load and humidity is analyzed. Numerical evaluation of the equilibrium constraint is in agreement with the knuckle-walking quadruped position of African apes. Bipedality is clearly incompatible with the usual clinging and mounting pattern of infant carrying, requiring a revision of models of hominization in relation to the divergence between apes and hominins. These results suggest that safe carrying of heavy infants justify the emergence of biped form of locomotion. Ways to test this possibility are foreseen here.
Topics: Animals; Biomechanical Phenomena; Gorilla gorilla; Hair; Hominidae; Humans; Hylobates; Lifting; Maternal Behavior; Paternal Behavior; Pongo pygmaeus
PubMed: 18030438
DOI: 10.1007/s00114-007-0325-0 -
TheScientificWorldJournal Oct 2013The hair follicle is a skin integument at the boundary between an organism and its immediate environment. The biological role of the human hair follicle has lost some of... (Review)
Review
The hair follicle is a skin integument at the boundary between an organism and its immediate environment. The biological role of the human hair follicle has lost some of its ancestral importance. However, an indepth investigation of this miniorgan reveals hidden complexity with huge research potential. An essential consideration when dealing with human research is the awareness of potential harm and thus the absolute need not to harm--a rule aptly qualified by the Latin term "primum non nocere" (first do no harm). The plucked hair shaft offers such advantages. The use of stem cells found in hair follicles cells is gaining momentum in the field of regenerative medicine. Furthermore, current diagnostic and clinical applications of plucked hair follicles include their use as autologous and/or three-dimensional epidermal equivalents, together with their utilization as surrogate tissue in pharmacokinetic and pharmacodynamics studies. Consequently, the use of noninvasive diagnostic procedures on hair follicle shafts, posing as a surrogate molecular model for internal organs in the individual patient for a spectrum of human disease conditions, can possibly become a reality in the near future.
Topics: Biochemistry; Hair; Humans; Stem Cell Research; Stem Cells
PubMed: 24302865
DOI: 10.1155/2013/620531 -
Cellular and Molecular Life Sciences :... Apr 2013MicroRNAs have continued to attract enormous interest in the scientific community ever since their discovery. Their allure stems from their unique role in... (Review)
Review
MicroRNAs have continued to attract enormous interest in the scientific community ever since their discovery. Their allure stems from their unique role in posttranscriptional gene expression control as well as their potential application as therapeutic targets in various disease pathologies. While much is known concerning their general biological function, such as their interaction with RNA-induced silencing complexes, many important questions still remain unanswered, especially regarding their functions in the skin. In this review, we summarize our current knowledge of the role of microRNAs in the skin in order to shine new light on our understanding of cutaneous biology and emphasize the significance of these small, single-stranded RNA molecules in the largest organ of the human body. Key events in epidermal and hair follicle biology, including differentiation, proliferation, and pigmentation, all involve microRNAs. We explore the role of microRNAs in several cutaneous processes, such as appendage formation, wound-healing, epithelial-mesenchymal transition, carcinogenesis, immune response, and aging. In addition, we discuss current trends in research and offer suggestions for future studies.
Topics: Animals; Culture; Epithelial-Mesenchymal Transition; Hair; Hair Follicle; Humans; MicroRNAs; Models, Biological; Phylogeny; Science; Skin; Skin Physiological Phenomena
PubMed: 22983383
DOI: 10.1007/s00018-012-1117-z -
CMAJ : Canadian Medical Association... Dec 1985
Topics: Hair; Humans; Minerals
PubMed: 4063917
DOI: No ID Found -
PloS One 2015Thymosin beta-4 (Tβ4) is known to induce hair growth and hair follicle (HF) development; however, its mechanism of action is unknown. We generated mice that...
Thymosin beta-4 (Tβ4) is known to induce hair growth and hair follicle (HF) development; however, its mechanism of action is unknown. We generated mice that overexpressed Tβ4 in the epidermis, as well as Tβ4 global knockout mice, to study the role of Tβ4 in HF development and explore the mechanism of Tβ4 on hair growth. To study Tβ4 function, we depilated control and experimental mice and made tissue sections stained with hematoxylin and eosin (H&E). To explore the effect of Tβ4 on hair growth and HF development, the mRNA and protein levels of Tβ4 and VEGF were detected by real-time PCR and western blotting in control and experimental mice. Protein expression levels and the phosphorylation of P38, ERK and AKT were also examined by western blotting. The results of depilation indicated that hair re-growth was faster in Tβ4-overexpressing mice, but slower in knockout mice. Histological examination revealed that Tβ4-overexpressing mice had a higher number of hair shafts and HFs clustered together to form groups, while the HFs of control mice and knockout mice were separate. Hair shafts in knockout mice were significantly reduced in number compared with control mice. Increased Tβ4 expression at the mRNA and protein levels was confirmed in Tβ4-overexpressing mice, which also had increased VEGF expression. On the other hand, knockout mice had reduced levels of VEGF expression. Mechanistically, Tβ4-overexpressing mice showed increased protein expression levels and phosphorylation of P38, ERK and AKT, whereas knockout mice had decreased levels of both expression and phosphorylation of these proteins. Tβ4 appears to regulate P38/ERK/AKT signaling via its effect on VEGF expression, with a resultant effect on the speed of hair growth, the pattern of HFs and the number of hair shafts.
Topics: Animals; Base Sequence; Epidermis; Gene Expression Regulation; Gene Knockout Techniques; Hair; Hair Follicle; Humans; MAP Kinase Signaling System; Mice; Neovascularization, Physiologic; Phosphatidylinositol 3-Kinases; Protein Kinase C; Thymosin; Vascular Endothelial Growth Factor A; Wnt Signaling Pathway
PubMed: 26083021
DOI: 10.1371/journal.pone.0130040 -
The Journal of Investigative... Dec 1999During organogenesis, the issue of size regulation is as important as shape and differentiation. We propose that the regulation of the dimensions of the epithelium and... (Review)
Review
During organogenesis, the issue of size regulation is as important as shape and differentiation. We propose that the regulation of the dimensions of the epithelium and its appendages (length, width, thickness) are based on regulation of cell numbers in specific sites, reflecting the input and output of cells in that region. This process is in turn regulated by the flow from the domain of proliferating cells to the domain of postmitotic differentiated cells. When the homeobox gene Msx-2 is over-expressed in transgenic mice under the control of the CMV promoter, the epidermis is thickened with hyperproliferation and hyperkeratosis. Hairs are shorter and the matrix region is shrunken. We suggest that Msx-2 may be one of the regulators involved in the control of organ size, and the above phenotypes are the manifestations of an increased cellular flow from proliferation domain to differentiation domain in the tissue.
Topics: Animals; Cell Differentiation; Cell Division; DNA-Binding Proteins; Epidermis; Gene Expression Regulation; Hair; Homeodomain Proteins; Humans; Mice
PubMed: 10674381
DOI: 10.1038/sj.jidsp.5640229