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Hair Follicles (hair + follicle)
Kinds of Hair Follicles Terms modified by Hair Follicles Selected AbstractsHAIR SAMPLING AND GENOTYPING FROM HAIR FOLLICLES: A MINIMALLY-INVASIVE ALTERNATIVE FOR GENETICS STUDIES IN SMALL, MOBILE PINNIPEDS AND OTHER MAMMALSMARINE MAMMAL SCIENCE, Issue 1 2007Abigail K. Caudron First page of article [source] Donor Harvesting: A New Approach to Minimize Transection of Hair FolliclesDERMATOLOGIC SURGERY, Issue 4 2000Damkerng Pathomvanich MD Background. There are several methods for harvesting donor hairs, including punch excision, single-bladed knife excision, and multibladed knife excision. All of these procedures are blind and thus result in transection of hair follicles. Transection of hair follicles during harvesting results in fewer follicles being available for transplantation, detrimentally affecting the final cosmetic result. Objective. To explore a new method of donor hair harvesting called "donor dissecting." This new procedure is an open technique because hair follicles are directly visualized during the harvesting process. Methods. The technique of donor dissecting utilizes a #15 scalpel blade to excise the donor hair ellipse from the occiput while maintaining meticulous hemostasis. This enables individual hair follicles to be visualized and protected from transection during the harvesting process. Once the donor ellipse is harvested, it is then further divided into individual mini- and micrografts using direct visualization of individual follicles to again prevent transection. Results. The technique of donor dissecting was utilized in 50 consecutive hair transplant patients. Utilizing this new technique, only 1.9% of hair follicles in the donor ellipse were transected during the harvesting process. The dissection of the donor ellipse 1.2% follicles being transected in the graft cutting process. Combining the donor dissection technique with dissection of the individual grafts, we were able to transect 1.59% of hair follicles harvested for transplantation. Conclusion. The technique of donor dissection minimizes the transection of hair follicles in the donor hair harvesting phase of hair transplantation. This technique is superior to the blind methods of donor harvesting which have been plagued by the problem of hair follicle transection. [source] Onycotrychia?: subungual hair follicle as another cause of longitudinal melanonychia or pigmentation,,,Hair follicle as cause of melanonychiaJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 10 2010O Ferreira No abstract is available for this article. [source] Expression pattern of somatostatin receptor subtypes 1,5 in human skin: an immunohistochemical study of healthy subjects and patients with psoriasis or atopic dermatitisEXPERIMENTAL DERMATOLOGY, Issue 12 2006Lena Hagströmer Abstract:, In psoriasis and atopic dermatitis, the inflammatory events have neurogenic components and the neuropeptides modify the functions of immuno-active cells in the skin. Somatostatin is a neuropeptide with several neuroendocrine and immunomodulating properties and mediates its actions by five distinct subtypes of G-protein-coupled receptors (SSTR1-5). This study describes the distribution of SSTR1,5, analysed with immunohistochemistry, in psoriasis, atopic dermatitis and controls. Normal human skin and lesional skin from patients with psoriasis or atopic dermatitis showed many similarities, but also some differences, as regards SSTR expression. SSTR1,3 were strongly expressed in the epidermis of healthy skin, and in the skin of patients with psoriasis or atopic dermatitis. It is noteworthy that SSTR4 and 5 were strongly expressed in the epidermis of psoriasis patients, but weakly expressed in the epidermis of those with atopic dermatitis and normal skin. The intensity of the staining also varied considerably between the different layers of the epidermis, especially in psoriasis patients. In all cases, the dendritic cells, found mostly in the papillary and upper reticular dermis, showed a strong expression of SSTR1,4, but a weak expression of SSTR5. SSTR1,5 were strongly expressed in the sweat glands in all skin biopsies. Hair follicles and sebaceous glands expressed all five subtypes. Striated muscle fibres showed an intense positive expression of SSTR1,4, but a weak or negative expression of SSTR5. The wide distribution and expression pattern of all five SSTRs in human skin suggest that somatostatin is involved in the interactions between the nervous system and the skin. [source] In Vivo Follicular Unit Multiplication: Is It Possible to Harvest an Unlimited Donor Supply?DERMATOLOGIC SURGERY, Issue 11 2006ERGIN ER MD BACKGROUND Follicular unit extraction is a process of removing one follicular unit at a time from the donor region. The most important limitation of this surgical procedure is a high transection rate. OBJECTIVE In this clinical study, we have transplanted different parts of transected hair follicle by harvesting with the follicular unit extraction technique (FUE) in five male patients. MATERIALS AND METHODS In each patient, three boxes of 1 cm2 are marked at both donor and recipient sites. The proximal one-third, one-half, and two-thirds of 15 hair follicles are extracted from each defined box and transplanted in recipient boxes. The density is determined at 12 months after the procedure. RESULTS A mean of 3 (range, 2,4) of the proximal one-third, 4.4 (range, 2,6) of the proximal one-half, and 6.2 (range, 5,8) of the proximal two-thirds of the transplanted follicles were observed as fully grown after 1 year. At the donor site, the regrowth rate was a mean of 12.6 (range, 10,14) of the proximal one-third, 10.2 (range, 8,13) of the proximal one-half, and 8 (range, 7,12) of the proximal two-thirds, respectively. CONCLUSION The survival rate of the transected hair follicles is directly related to the level of transection. Even the transected parts, however, can survive at the recipient site; the growth rate is not satisfactory and they are thinner than the original follicles. We therefore recommend that the surgeon not transplant the sectioned parts and be careful with the patients whose transection rate is high during FUE procedures. [source] Multiply Recurrent Trichilemmal Carcinoma With Perineural Invasion and Cytokeratin 17 PositivityDERMATOLOGIC SURGERY, Issue 8 2003Julie E. Allee MD Background. Trichilemmal carcinoma is an uncommon cutaneous malignancy that is thought to be the malignant counterpart of the trichilemmoma. Despite histologic features such as pronounced cytologic atypia, trichilemmal carcinoma is often described as having a rather benign clinical course. Cases of tumor recurrence after therapy are uncommon, and tumor neurotropism has never been described. objective. A case of multiply recurrent trichilemmal carcinoma with perineural invasion is described. The outer root sheath differentiation of this neoplasm is confirmed with the use of novel antibodies directed toward cytokeratins that are expressed in this area of the hair follicle. Methods. The trichilemmal carcinoma was excised using the Mohs surgical technique. Tissue obtained during the extirpation of the tumor was subjected to immunohistochemical staining for cytokeratin 15, cytokeratin 17, and c-erb-B2. Results. Tumor neurotropism was noted. The trichilemmal carcinoma demonstrated abundant cytoplasmic staining for cytokeratin 17 and c-erb-B2. Conclusions. In distinction to previous reports, this case reveals that trichilemmal carcinoma can demonstrate significant biological aggression, as reflected by tumor neurotropism and by failure to respond to multiple surgical excisions. The purported outer root sheath differentiation of this neoplasm is confirmed with the use of novel immunohistochemical staining. This immunohistochemical staining may be useful in differentiating trichilemmal carcinoma from other clear cell neoplasms. [source] Androgens and hair growthDERMATOLOGIC THERAPY, Issue 5 2008Valerie Anne Randall ABSTRACT:, Hair's importance in human communication means that abnormalities like excess hair in hirsutism or hair loss in alopecia cause psychological distress. Androgens are the main regulator of human hair follicles, changing small vellus follicles producing tiny, virtually invisible hairs into larger intermediate and terminal follicles making bigger, pigmented hairs. The response to androgens varies with the body site as it is specific to the hair follicle itself. Normally around puberty, androgens stimulate axillary and pubic hair in both sexes, plus the beard, etc. in men, while later they may also inhibit scalp hair growth causing androgenetic alopecia. Androgens act within the follicle to alter the mesenchyme,epithelial cell interactions, changing the length of time the hair is growing, the dermal papilla size and dermal papilla cell, keratinocyte and melanocyte activity. Greater understanding of the mechanisms of androgen action in follicles should improve therapies for poorly controlled hair disorders like hirsutism and alopecia. [source] Etiology of cicatricial alopecias: a basic science point of viewDERMATOLOGIC THERAPY, Issue 4 2008Kevin J. McElwee ABSTRACT: This article presents a short summary of our current knowledge of cicatricial alopecia disease pathogenesis and the hypothetical disease mechanisms that may be involved in scarring alopecia development. Several forms of scarring alopecia likely involve targeted cytotoxic action against hair follicle cells mediated by a folliculocentric inflammation. However, the specific nature of the inflammatory interference in hair follicle growth is open to question. A popular hypothesis of lymphocyte-mediated scarring alopecia development involves autoimmune targeting of hair follicle,specific self-antigens, although there is no direct evidence in support of such a view. Alternative hypotheses focus on defects in sebaceous gland function, destruction of hair follicle stem cells, and interference in the communication between hair follicle mesenchyme and epithelium. Many questions arise from these hypotheses, and addressing them with a systematic research approach may enable significant advances in understanding cicatricial alopecia etiology. [source] Iris as a recipient tissue for pigment cells: Organized in vivo differentiation of melanocytes and pigmented epithelium derived from embryonic stem cells in vitroDEVELOPMENTAL DYNAMICS, Issue 9 2008Hitomi Aoki Abstract Regenerative transplantation of embryonic stem (ES) cell-derived melanocytes into adult tissues, especially skin that includes hair follicles or the hair follicle itself, generally not possible, whereas that of ES cell-derived pigmented epithelium was reported previously. We investigated the in vivo differentiation of these two pigment cell types derived from ES cells after their transfer into the iris. Melanocytes derived from ES cells efficiently integrated into the iris and expanded to fill the stromal layer of the iris, like those prepared from neonatal skin. Transplanted pigmented epithelium from either ES cells or the neonatal eye was also found to be integrated into the iris. Both types of these regenerated pigment cells showed the correct morphology. Regenerated pigment epithelium expressed its functional marker. Functional blocking of signals required for melanocyte development abolished the differentiation of transplanted melanocytes. These results indicate successful in vivo regenerative transfer of pigment cells induced from ES cells in vitro. Developmental Dynamics 237:2394,2404, 2008. © 2008 Wiley-Liss, Inc. [source] Runx3 is involved in hair shape determinationDEVELOPMENTAL DYNAMICS, Issue 4 2005Eli Raveh Abstract Transcriptional regulators of the Runx family play critical roles in normal organ development and, when mutated, lead to genetic diseases and cancer. Runx3 functions during cell lineage decisions in thymopoiesis and neurogenesis and mediates transforming growth factor-, signaling in dendritic cells. Here, we study the function of Runx3 in the skin and its appendages, primarily the hair follicle, during mouse development. Runx3 is expressed predominantly in the dermal compartment of the hair follicles as they form and during the hair cycle, as well as in the nail and sweat gland skin appendages. Distinct expression is also detected periodically in isolated cells of the epidermis and in melanocytes, populating the hair bulb. Runx3 -deficient mice display a perturbation of the normal hair coat, which we show to be due to hair type and hair shape changes. Thus, one of the functions of Runx3 in skin may be to regulate the formation of the epithelial derived structural hair by affecting dermal to epidermal interactions. Developmental Dynamics 233:1478,1487, 2005. © 2005 Wiley-Liss, Inc. [source] Polyamines and hair: a couple in search of perfectionEXPERIMENTAL DERMATOLOGY, Issue 9 2010Yuval Ramot Please cite this paper as: Polyamines and hair: a couple in search of perfection. Experimental Dermatology 2010; 19: 784,790. Abstract:, Polyamines (spermidine, putrescine and spermine) are multifunctional cationic amines that are indispensable for cellular proliferation; of key significance in the growth of rapidly regenerating tissues and tumors. Given that the hair follicle (HF) is one of the most highly proliferative organs in mammalian biology, it is not surprising that polyamines are crucial to HF growth. Indeed, growing (anagen) HFs show the highest activity of ornithine decarboxylase (ODC), the rate-limiting enzyme of polyamine biosynthesis, while inhibition of ODC, using eflornithine, results in a decreased rate of excessive facial hair growth in vivo and inhibits human scalp hair growth in organ culture. In sheep, manipulation of dietary intake of polyamines also results in altered wool growth. Polyamine-containing nutraceuticals have therefore been proposed as promoters of human hair growth. Recent progress in polyamine research, coupled with renewed interest in the role of polyamines in skin biology, encourages one to revisit their potential roles in HF biology and highlights the need for a systematic evaluation of their mechanisms of action and clinical applications in the treatment of hair disorders. The present viewpoint essay outlines the key frontiers in polyamine-related hair research and defines the major open questions. Moreover, it argues that a renaissance in polyamine research in hair biology, well beyond the inhibition of ODC activity in hirsutism therapy, is important for the development of novel therapeutic strategies for the manipulation of human hair growth. Such targets could include the manipulation of polyamine biosynthesis and the topical administration of selected polyamines, such as spermidine. [source] Functional characterization of highly adherent CD34+ keratinocytes isolated from human skinEXPERIMENTAL DERMATOLOGY, Issue 7 2010Araika Gutiérrez-Rivera Please cite this paper as: Functional characterization of highly adherent CD34+ keratinocytes isolated from human skin. Experimental Dermatology 2010; 19: 685,688. Abstract:, Compared to murine models, data on cells responsible for the homeostasis of human epidermis are scarce and often contradictory. Given the conflicting results and the availability of clinical grade protocols to purify CD34 cells from a given tissue, we pursued to phenotypically characterize human epidermal CD34+ population. After magnetic separation of whole skin CD34+ and CD34, cell fractions and selection for cells highly adherent to extracellular matrix, both CD34± fractions retained the ability to form a stratified epidermis in organotypic cultures and presented similar in vitro migratory phenotypes. However CD34, cells showed higher clonogenic potential and in vitro proliferative capacity. These results indicated that CD34, cell fraction contains stem/early progenitor cells, while CD34+ cells might be a transit-amplifying precursor for hair follicle (HF) sheath cells. The ability to isolate living cells using differential cell adhesion and surface markers provides an opportunity to study cells from different morphological regions of the HF. [source] Exploration of the functional hierarchy of the basal layer of human epidermis at the single-cell level using parallel clonal microcultures of keratinocytesEXPERIMENTAL DERMATOLOGY, Issue 4 2010Nicolas O. Fortunel Please cite this paper as: Exploration of the functional hierarchy of the basal layer of human epidermis at the single-cell level using parallel clonal microcultures of keratinocytes. Experimental Dermatology 2010. Abstract:, The basal layer of human epidermis contains both stem cells and keratinocyte progenitors. Because of this cellular heterogeneity, the development of methods suitable for investigations at a clonal level is dramatically needed. Here, we describe a new method that allows multi-parallel clonal cultures of basal keratinocytes. Immediately after extraction from tissue samples, cells are sorted by flow cytometry based on their high integrin-,6 expression and plated individually in microculture wells. This automated cell deposition process enables large-scale characterization of primary clonogenic capacities. The resulting clonal growth profile provided a precise assessment of basal keratinocyte hierarchy, as the size distribution of 14-day-old clones ranged from abortive to highly proliferative clones containing 1.7 × 105 keratinocytes (17.4 cell doublings). Importantly, these 14-day-old primary clones could be used to generate three-dimensional reconstructed epidermis with the progeny of a single cell. In long-term cultures, a fraction of highly proliferative clones could sustain extensive expansion of >100 population doublings over 14 weeks and exhibited long-term epidermis reconstruction potency, thus fulfilling candidate stem cell functional criteria. In summary, parallel clonal microcultures provide a relevant model for single-cell studies on interfollicular keratinocytes, which could be also used in other epithelial models, including hair follicle and cornea. The data obtained using this system support the hierarchical model of basal keratinocyte organization in human interfollicular epidermis. [source] Hair growth inhibition by psychoemotional stress: a mouse model for neural mechanisms in hair growth controlEXPERIMENTAL DERMATOLOGY, Issue 1 2006Eva M. J. Peters Abstract:, Stress has long been discussed controversially as a cause of hair loss. However, solid proof of stress-induced hair growth inhibition had long been missing. If psychoemotional stress can affect hair growth, this must be mediated via definable neurorendocrine and/or neuroimmunological signaling pathways. Revisiting and up-dating relevant background data on neural mechanisms of hair growth control, we sketch essentials of hair follicle (HF) neurobiology and discuss the modulation of murine hair growth by neuropeptides, neurotransmitters, neurotrophins, and mast cells. Exploiting an established mouse model for stress, we summarize recent evidence that sonic stress triggers a cascade of molecular events including plasticity of the peptidergic peri- and interfollicular innervation and neuroimmune crosstalk. Substance P (SP) and NGF (nerve growth factor) are recruited as key mediators of stress-induced hair growth-inhibitory effects. These effects include perifollicular neurogenic inflammation, HF keratinocyte apoptosis, inhibition of proliferation within the HF epithelium, and premature HF regression (catagen induction). Intriguingly, most of these effects can be abrogated by treatment of stressed mice with SP-receptor neurokinin-1 receptor (NK-1) antagonists or NGF-neutralizing antibodies , as well as, surprisingly, by topical minoxidil. Thus there is now solid in vivo -evidence for the existence of a defined brain- HF axis. This axis can be utilized by psychoemotional and other stressors to prematurely terminate hair growth. Stress-induced hair growth inhibition can therefore serve as a highly instructive model for exploring the brain-skin connection and provides a unique experimental model for dissecting general principles of skin neuroendocrinology and neuroimmunology well beyond the HF. [source] Reorganization of hair follicles in human skin organ culture induced by cultured human follicle-derived cellsEXPERIMENTAL DERMATOLOGY, Issue 8 2005Walter Krugluger Abstract:, Studies of human hair follicle (HF) induction by follicle-derived cells have been limited due to a lack of suitable test systems. In this study, we established a skin organ culture system which supports HF formation by follicle-derived cells. Long-term skin organ cultures were set up from human retroauricular skin specimens and maintained in culture for up to 8 weeks. In vitro expanded human HF-derived cells from the dermal papilla (DP) and the outer root sheath (ORS) were injected together into the skin specimens and evaluated for their ability to induce reorganization of HFs. Macroscopic analysis of the cultured skin specimens demonstrated the growth of velus-like hair after 4 weeks in culture. Histologic evaluation of the cultured skin specimens after 8 weeks of culture revealed multiple miniaturized HFs with sebaceous glands. In addition, cell clusters of various differentiation stages could be demonstrated in serial sections of the cultured skin specimens. Labeling of HF-derived cells with the fluorescence dye CFDA-1 prior to injection suggested a de novo reorganization of HFs out of the injected cells. In conclusion, the study demonstrated HF formation by HF-derived cells in an in vitro skin organ culture model. [source] Desmocollin 1 expression and desmosomal remodeling during terminal differentiation of human anagen hair follicle: an electron microscopic studyEXPERIMENTAL DERMATOLOGY, Issue 5 2004Elena Donetti Abstract:, The terminal differentiation (TD) program of keratinocytes of the human hair follicle (HF) occurs with specific temporal and spatial features in the various layers of the inner root sheath (IRS) and in the innermost layer of the outer root sheath (companion layer). This process is characterized by complex nuclear and cytoplasmic morphological changes, accompanied by profound modifications in intercellular junctions. As no correlation exists between the structure and the molecular composition of desmosomes during TD of the IRS/companion unit, the aim of our study was to investigate by transmission electron microscopy the remodeling of desmosomes in keratinizing cells of these compartments. By immunogold post embedding technique, we studied in anagen HFs the modulation of the synthesis of desmocollin 1 (Dsc1), a transmembrane glycoprotein specifically synthesized in the IRS and in the companion layer. Dsc1 immunoreactivity was actually confined to these compartments and tended to increase just before the level of TD, particularly in the Henle's layer and in the IRS cuticle. In Huxley's layer, the immunolabeling was patchy and in the companion layer Dsc1 synthesis was detected above the level of keratinization of Huxley's layer. In the whole IRS, concomitantly with TD, there was an abrupt and almost complete disappearance of Dsc1 synthesis. An asymmetric distribution of Dsc1 was noticed (i) between cells at different stages of differentiation and (ii) between cells belonging to layers with different spatial/temporal features of TD. Our results show that the ultrastructural modifications of desmosomes during TD of HF are paralleled by the modulation of the synthesis of desmocollin 1. [source] 17,-estradiol induces aromatase activity in intact human anagen hair follicles ex vivoEXPERIMENTAL DERMATOLOGY, Issue 4 2002R. Hoffmann Abstract: For topical treatment of androgenetic alopecia (AGA) in women, solutions containing either estradiol benzoate, estradiol valerate, 17,- or 17,-estradiol are commercially available in Europe and some studies show an increased anagen and decreased telogen rate after treatment as compared with placebo. At present it is not precisely known how estrogens mediate their beneficial effect on AGA-affected hair follicles. We have shown recently that 17,-estradiol is able to diminish the amount of dihydrotestosterone (DHT) formed by human hair follicles after incubation with testosterone, while increasing the concentration of weaker steroids such as estrogens. Because aromatase is involved in the conversion of testosterone to estrogens and because there is some clinical evidence that aromatase activity may be involved in the pathogenesis of AGA, we addressed the question whether aromatase is expressed in human hair follicles and whether 17,-estradiol is able to modify the aromatase activity. Herewith we were able to demonstrate that intact, microdissected hair follicles from female donors express considerably more aromatase activity than hair follicles from male donors. Using immunohistochemistry, we detected the aromatase mainly in the epithelial parts of the hair follicle and not in the dermal papilla. Furthermore, we show that in comparison to the controls, we noticed in 17,-estradiol-incubated (1 nM) female hair follicles a concentration- and time-dependent increase of aromatase activity (at 24 h: 1 nM = +18%, 100 nM = +25%, 1 µM = +57%; 24 h: 1 nM = +18%, 48 h: 1 nM = +25%). In conclusion, our ex vivo experiments suggest that under the influence of 17,-estradiol an increased conversion of testosterone to 17,-estradiol and androstendione to estrone takes place, which might explain the beneficial effects of estrogen treatment of AGA. [source] Trans-species hair growth induction by human hair follicle dermal papillaeEXPERIMENTAL DERMATOLOGY, Issue 4 2001C. A. B. Jahoda Abstract: A series of experimental bioassays has shown that the dermal papilla of the adult rodent vibrissa hair follicle retains unique inductive properties. In view of the many phenotypic and functional differences between specific hair follicle types, and the growing interest in hair follicle biology and disease, it remains important to establish that the human hair follicle dermal papilla has equivalent capabilities. In this study we tested the ability of human hair follicle papillae to induce hair growth when implanted into transected, athymic mouse vibrissa follicles. The implanted papillae that interacted with mouse follicle epithelium created new fibre-producing follicle end bulbs. The origin of the papillae in the recombinant structures was confirmed using laser capture microdissection and human specific gender determination by PCR. The demonstration that intact adult human dermal papillae can induce hair growth has implications for molecular analysis of basic hair growth mechanisms, particularly since the study involved common epithelial,mesenchymal signalling and recognition properties across species. It also improves the prospects for a cell-based clinical approach to hair follicle disorders. [source] Construction and characterization of a doxycycline-inducible transgenic system in Msx2 expressing cellsGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 5 2009Congxing Lin Abstract Homeobox gene Msx2 is widely expressed during both embryogenesis and postnatal development and plays important roles during organogenesis. We developed an Msx2 -rtTA BAC transgenic line which can activate TetO-Cre expression in Msx2 -expressing cells upon doxycycline (Dox) treatment. Using the Rosa26-LacZ (R26R) reporter line, we show that rtTA is activated in Msx2 -expressing organs including the limb, heart, external genitalia, urogenital system, hair follicles and craniofacial regions. Moreover, we show that in body appendages, the transgene can be activated in different domains depending on the timing of Dox treatment. In addition, the transgene can also be effectively activated in adult tissues such as the hair follicle and the urogenital system. Taken together, this Msx2 -rtTA;TetO-Cre system is a valuable tool for studying gene function in the development of the aforementioned organs in a temporal and spatially-restricted manner, as well as for tissue lineage tracing of Msx2 -expressing cells. When induced postnatally, this system can also be used to study gene function in adult tissues without compromising normal development and patterning. genesis 47:352,359, 2009. © 2009 Wiley-Liss, Inc. [source] 6-O glucose linoleate supports in vitro human hair growth and lipid synthesisINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2007P. Vingler Synopsis The hair follicle is a very active organ with a complex structure, which produces a hair fibre at a rate of 0.3 mm a day. Accordingly, the hair follicle is highly demanding in energy source, as the hair bulb matrix cells are endowed with one of the highest rates of proliferation in the human body. Moreover, recent data have shown the involvement of lipids in hair follicle function. As in vitro -grown hair follicle keeps producing a hair fibre that closely resembles the natural hair fibre, we decided to use this model to investigate the role of a new of glucose linoleate derivative (6-O-linoleyl- d -glucose: 6-O-GL) as a lipid precursor and energy provider. Our results demonstrated that 6-O-GL was (i) quite stable and surprisingly resistant to oxidative degradation, and (ii) readily taken up and metabolized by the hair follicle into various lipids, namely neutral lipids, ceramides and polar lipids. Moreover, it supported hair follicle growth and survival in a glucose- and linoleic-acid free medium. 6-O-GL thus appeared to be a bi-functional nutrient, ensuring both proper fibre quality and production by the hair follicle. Résumé Le follicule pileux est un organe très actif et d'une structure très complexe, qui produit la tige pilaire au rythme de 0.3 mm par jour. En conséquence, le follicule pileux est très demandeur en ressources énergétiques, les cellules de la matrice bulbaire ayant un des taux de prolifération les plus élevé de l'organisme. De plus des études récentes ont mis en évidence le rôle de lipides dans le fonctionnement du follicule pileux. Puisque le follicule pileux in vitro continue à produire une fibre de qualité identique à celle d'une fibre naturelle, nous avons décidé d'utiliser ce modèle pour étudier le rôle d'un nouveau linoléate de glucose (6-O-linoleyl- d -glucose: 6-O-GL) en tant que précurseur lipidique et source d'énergie. Nos résultats démontrent que le 6-O-GL est très stable et étonnamment résistant à l'auto oxydation, qu'il est capté et métabolisé par le follicule pileux en divers lipides, neutres, polaires et céramides. De plus, le 6-O-GL soutient la croissance et la survie du follicule dans un milieu dépourvu de glucose et d'acide linoléique. Le 6-O-GL apparaît donc comme un agent bi-fonctionnel, permettant au follicule pileux de maintenir in vitro la production de la tige pilaire. [source] Hair biology: an updateINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2002B. A. Bernard Synopsis In the past few years, the hair follicle has started revealing its beauty and mysteries. The existence of a growth and regeneration cycle, together with a unique tissue organization and complex regulatory network, make it a true paradigm of tissue homeostasis and dermal,epithelial crosstalk. In this brief review, I will describe some of the most recent results obtained in this very active research field of hair biology, underlining the diversity of the molecular signals that control hair growth and pigmentation. Résumé Au cours des dernières années, le follicule pileux a commencéà révéler sa beauté et ses mystères. L'existence d'un cycle de croissance et de régénération, d'une organization tissulaire unique et d'un circuit complexe de régulation désigne le follicule pileux comme un paradigme d'homéostasie tissulaire et d'interactions dermo,épithéliales. Dans cette courte revue, je décris quelques uns des résultats récemment obtenus dans ce domaine de recherche très actif, en soulignant l'extrême diversité des signaux moléculaires qui contrôlent la croissance du cheveu et sa pigmentation. [source] Sporadic dystrophic epidermolysis bullosa with albopapuloid and prurigo- and folliculitis-like lesionsINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 8 2009Yi-Ming Fan MD A case of sporadic dystrophic epidermolysis bullosa (DEB) with albopapuloid and prurigo- and folliculitis-like lesions is reported. Histopathology of the scalp biopsy showed hyperkeratosis, a subepidermal cleft near the orifice of a hair follicle, dermal fibrosis, and a moderate perivascular and perifollicular lymphohistiocytic inflammatory cell infiltrate in the papillary dermis, without neutrophilic infiltrate in the orifice of the hair follicle. It is uncertain whether the present case should be classified as DEB pruriginosa or represents a new subtype of DEB. [source] Validity of methyl mercury hair analysis: mercury monitoring in human scalp/nude mouse modelJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2008Grazyna Zareba Abstract Objective. The grafting of human scalp hair was used as a new application of this method to explore methyl mercury incorporation into human hair and to validate this model for mercury monitoring in hair. Methods. Human scalp grafts were transplanted to athymic BALB/c nude mice. The animals were exposed to methyl mercury either as a single dose i.p. or continuously for 4 months, using ALZET osmotic pumps. The mercury concentration in hair was determined using x-ray fluorescence (XRF) spectrometry by segmental (2 mm) analysis of a single strand, and tissue concentrations were measured by cold vapor atomic absorption analysis. Results. Human scalp hair grown in nude mice showed long-term persistence of human features including the expression of histocompatibility antigens (KAB 3, W 6/32, SF 1-1.1.1) and normal hair morphometry. The disposition of methyl mercury in nude mice followed a one-compartment model with a whole body elimination half-life of 6.7 days (elimination constant, k = 0.1/day). Autoradiographic studies revealed that methyl mercury was rapidly incorporated into areas of the hair follicle undergoing active keratinization. Methyl mercury concentrations in human hair transplanted onto nude mice were two orders of magnitude higher than in blood and attained a mean hair: blood ratio of 217 : 1, similar to ratios reported only in human studies. Conclusions. This study demonstrated that human hair grown on nude mice can record the level of exposure to methyl mercury and can serve as a valuable research tool to study mercury incorporation into human hair. Copyright © 2007 John Wiley & Sons, Ltd. [source] Upregulation of genes orchestrating keratinocyte differentiation, including the novel marker gene ID2, by contact sensitizers in human bulge-derived keratinocytesJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 1 2010Yoshie Yoshikawa Abstract In the epidermis, keratinocytes are involved in physical and first-line immune protection of the host. In this study, we analyzed the molecular responses to certain contact sensitizers (2,4-dinitrochlorobenzene and NiSO4) and irritants (sodium dodecyl sulfate and benzalkonium chloride) in cultured human keratinocytes from the bulge region of a plucked hair follicle (bulge-derived keratinocytes [BDKs]) and compared these molecular responses to those with the human monocytic leukemia cell line, THP-1. The BDKs, individually established without invasive biopsies, showed high reactivity to these stimulants. As a primary response to the contact sensitizers, the NRF2-mediated signaling pathway was upregulated in BDKs and THP-1. The expression of IL1B and IL8 genes was not induced by the irritants but by the sensitizers in THP-1. However, the expression of the IL1B and IL8 genes was induced at higher levels by the irritants in BDKs than by the sensitizers. Many genes orchestrating keratinocyte differentiation, including ID2, were significantly upregulated in response to the sensitizers in BDKs but not those in THP-1. The use of the ID2 gene to discriminate between sensitizers and irritants might be effective as a novel marker for application during in vitro sensitization with BDKs. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 24:10,20, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20307 [source] Expression patterns of MITF during human cutaneous embryogenesis: evidence for bulge epithelial expression and persistence of dermal melanoblastsJOURNAL OF CUTANEOUS PATHOLOGY, Issue 7 2008Briana C. Gleason Background:, The mechanisms whereby melanocytes populate the epidermis and developing hair follicles during embryogenesis are incompletely understood. Recent evidence implicates an intermediate mesenchymal stage in this evolutionary process in which HMB-45-positive melanocyte precursors (,melanoblasts') exist both in intradermal as well as intraepithelial and intrafollicular compartments. The melanocyte master transcriptional regulator, microphthalmia transcription factor (MITF), identifies mature melanocytes as well as melanocyte precursor stem cells that reside in the bulge region of the hair follicle. Methods:, To better define the use of MITF expression in the evaluation of melanocyte ontogeny, human embryonic and fetal skin samples (n = 28) at 6,24 weeks gestation were studied immunohistochemically for expression of MITF and Mart-1. Adjacent step sections were evaluated to correlate staining patterns with cell localization in the intraepidermal, intrafollicular and intradermal compartments. Results:, At 6,8 weeks, MITF and Mart-1-positive cells were primarily intradermal with only rare positive cells in the epidermis. By 12,13 weeks, most of these cells had migrated into the epidermis, predominantly the suprabasal layers. Between 15,17 weeks, these cells localized to the basal layer and colonized developing hair follicles. Rare intradermal MITF and Mart-1 positive cells were found as late as week 20. At 18,24 weeks, MITF and Mart-1 positive cells were identified in the outer root sheath, bulge, and follicular bulge epithelium, in addition to the epidermis. Unexpectedly, weak but diffuse nuclear MITF expression was also present in the keratinocytes of the bulge area. Conclusions:, The in situ migratory fate of MITF/Mart-1-expressing cells in fetal skin involves a well-defined progression from intradermal to intraepidermal to intrafollicular localization. Occasional intradermal melanocytes may persist after the intraepithelial stages are completed, a finding of potential significance to melanocytic proliferations that may arise de novo within the dermis. Because MITF may play a role in stem cell maintenance, the presence of MITF in bulge epithelial cells suggests that it may be a novel marker for follicular stem cells of both epithelial and melanocytic lineage. [source] Melanocytic nevi of the breast: a histologic case-control studyJOURNAL OF CUTANEOUS PATHOLOGY, Issue 2 2004F. Rongioletti Background:, Melanocytic nevi in the genital, acral, and flexural sites often display clinical and histologic features that may simulate melanoma. We verified whether this is the case also for nevi of the breast. Methods:, Eleven dermatopathologists, from nine Italian Institutions, collected the specimens of melanocytic lesions from the breast and other body sites, excluding the acral, genital, and flexural areas, as controls. Cases and controls were matched for sex and age. All nevi were observed ,blindly' and simultaneously by all participants. For each lesion, 10 histological parameters were analyzed: asymmetry, absence of lateral demarcation of melanocytes, lentiginous proliferation, nested and dyshesive pattern, intraepidermal melanocytes above the basal layer, involvement of the hair follicle, absence of maturation of dermal melanocytes, melanocytic atypia, fibroplasia of the papillary dermis, and lymphocytic dermal infiltrate. Each parameter was scored 2 when present and 1 when absent or not valuable. A total score was calculated for each lesion. Results were statistically analyzed by the chi-square test and the Mann,Whitney U -test. Results:, One hundred and one nevi came from the breast area and 97 from elsewhere. Breast nevi exhibited significantly more atypical features than nevi from other sites. In particular, breast nevi with intraepidermal melanocytes, melanocytic atypia, and dermal fibroplasia were significantly more numerous. We did not find any sexual difference. Conclusions:, To avoid undue concerns, dermatopathologists should be aware that melanocytic nevi of the breast may show a high degree of atypical features. [source] Melanocytic matricoma: case confirmation of a recently described entityJOURNAL OF CUTANEOUS PATHOLOGY, Issue 4 2003Christy M. Williams Background:, In 1999, Carlson et al. reported two cases of a matrical neoplasm that recapitulates the bulb of the anagen hair follicle, which they designated as melanocytic matricoma. Methods:, Here we report a similar case in a 78-year-old white male, who presented with a 0.4 cm purple-black firm papule in the left preauricular area. Results:, Histologically, the tumor is composed of a dual cell population including admixed epithelial matrical and supramatrical cells with "shadow" cell formation and pigmented dendritic melanocytes. Immunohistochemical studies for cytokeratin highlighted the epithelial component and studies for S-100 protein, HMB-45, and vimentin confirmed the melanocytic component. The differential diagnosis considered includes pigmented variants of pilomatricoma, matrical carcinoma, basal cell carcinoma and malignant melanoma. Conclusions:, The case reported herein is the first confirmation of melanocytic matricoma, a distinctive adnexal neoplasm with characteristic clinical and pathologic features, which differentiate it from pigmented pilomatricoma. [source] p63 expression in normal human epidermis and epidermal appendages and their tumorsJOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2003Miki Tsujita-Kyutoku Background:, p63, a member of the p53 gene family, is expressed in basal cells of several different organs. Methods:, The immunoreactivity of p63 was examined in normal human epidermis and epidermal appendages and their tumors, and compared with proliferative activity as evaluated by Ki-67. Results:, In normal skin, p63 expression was seen in basal/suprabasal cells of the epidermis, outer root sheath and hair matrix cells of the hair follicle, seboblast situated in the outermost layer of sebaceous glands, and outer layer cells of the ductal portion and myoepithelial cells of the secretory portion of the sweat glands. p63 expression was confined to the cells forming a continuous basal rim along the normal epithelial structure. In tumors, p63 expression resembled that in normal tissue in that tumor components originating from p63-positive cells were constantly positive for p63. In normal and tumor tissues, not all p63-positive cells were positive for Ki-67. Conclusions:, p63 expression may be a marker of basal/progenitor cells in tumors of epidermis and epidermal appendages, and may be a diagnostic marker of these tumors. [source] Chloracne: histopathologic findings in one caseJOURNAL OF CUTANEOUS PATHOLOGY, Issue 4 2002Maria Antonia Pastor Background: Chloracne is an acneiform eruption due to poisoning by halogenated aromatic compounds having a specific molecular shape. This condition is always a symptom of systemic poisoning by chemical chloracnegens and not just a cutaneous disorder. Methods: We have studied a patient with severe chloracne who showed cutaneous lesions involving mostly the face and the axillae. Results:, Histopathologic study of the facial lesions demonstrated that almost every vellus hair follicle was involved, showing a dilated infundibulum filled by a keratotic plug. This keratotic material was mostly composed of orthokeratotic basket-weave basophilic corneocytes, namely infundibular keratin, although there were also some dilated infundibula containing eosinophilic laminated or granular sebum at their center. Small infundibular cysts were more numerous than comedones. Mature and well-developed sebaceous glands were seen at the base of many of the dilated infundibula and no squamous metaplasia of the sebaceous glands or ducts could be demonstrated. Hyperpigmentation of the lesions resulted from hyperproduction of melanin by a normal number of melanocytes along the basal layer of the epidermis and infundibular epithelium. Abundant melanin granules also impregnated the corneocytes of the infundibular plugs. Conclusions:, Our findings support the notion that tiny infundibular cysts rather than comedones represent the basic lesions of chloracne. [source] De novo mutation in the mitochondrial tRNALeu(UUR) gene (A3243G) with rapid segregation resulting in MELAS in the offspringJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 1 2001CH Ko Abstract: A 14-year-old Chinese boy with a normal perinatal and early developmental history presented at 5 years of age with migraine, intractable epilepsy, ataxia, supraventricular tachycardia, paralytic ileus and progressive mental deterioration. Computerized tomography revealed multiple cerebral infarcts in the parieto-occipital region without basal ganglial calcification. Magnetic resonance imaging showed increased signal intensity in T2 weighted images in the same regions. A cerebral digital subtraction angiogram was normal. Venous lactate, pyruvate, lactate to pyruvate ratio and cerebrospinal fluid lactate were elevated. Muscle biopsy did not reveal any ragged red fibres; dinucleotide,tetrazolium reductase activity was normal. Mitochondrial DNA analysis detected an adenine to guanine mutation at nucleotide position 3243 of tRNALeu(UUR). All four tissues analysed demonstrated heteroplasmy: leucocyte 56%, hair follicle 70%; buccal cell 64%; muscle 54%. The mother and brother of the proband, both asymptomatic, were also found to have a heteroplasmic A3243G mutation in the leucocytes, hair follicle and buccal cells. Other members of the maternal lineage, including the maternal grandmother, did not have the mutation. This report describes a patient with mitochondrial encephalopathy, lactic acidosis, stroke-like episodes, who presented with multisystem involvement. The absence of ragged red fibres in muscle biopsy did not preclude the diagnosis. Mutational analysis of mitochodrial DNA conveniently confirmed the diagnosis of the disorder. A de novo mutaton is demonstrated in this family. [source] | ||||||||||||||||