Inconsistent with the view that hair follicle stem cells reside in the matrix area of the hair bulb, we found that label-retaining cells exist exclusively in the bulge area of the mouse hair follicle. The bulge consists of a subpopulation of outer root sheath cells located in the midportion of the follicle at the arrector pili muscle attachment site. Keratinocytes in the bulge area are relative...

Proliferating trichilemmal tumors (PTTs) are benign adnexal skin neoplasms that arise from the outer root sheath of the hair follicle. These tumors are most commonly observed on the scalp and occur, most of the time, in elderly women. Malignant transformation of these neoplasms is a rare event; less than 50 cases have been reported in the English medical literature. We present the case of a 39-...

Background Pilonidal sinus (PS) is considered to belong in the category of follicular occlusion diseases (acne triad). Objectives The aim of our study was to elucidate the pathogenesis of PS by evaluating its cytokeratin (CK) expression. Methods CK expression in nine cases of PS was studied immunohistochemically using six antikeratin antibodies. Results Infundibular-like epithelium contained CK...

Hair loss is a prevalent medical condition affecting both genders. In this study, we investigate the effects of specific class extracellular vesicles (EVs), namely human normal fibroblast-derived EVs (hFB-EVs), on dermal papilla (DP) and outer root sheath (ORS) cells examine molecular mechanisms responsible for hair growth in follicles (HFs). We find that Wnt3a, which maintains hair-generating ...

The structure of undischarged and discharged trichocysts has been examined in Paramecium caudatum, and their light-microscopic appearance compared with their fine-structural organization. In living specimens undischarged trichocysts appear to be of a single type with a unimodal variation in length about a mean of 37 fim. When fixed for electron microscopy or compressed beneath a coverslip many ...

Mycorrhiza is a mutualistic association between zone surrounding the root [2]. Although a lack in growth fungi and higher plants [1]. Different types of mycorrhizae response to VA-fungi inoculation in unsterilized soil was occur, distinguished by their morphology and to a also recorded, this result has been attributed to the fact certain extent, in their physiology. These include the that nativ...

Lateral disk herniation into the intervertebral foramen if not recognized may result in a negative surgical exploration. The condition is readily recognized by computed tomography (CT), which demonstrates a soft-tissue mass in the intervertebral foramen, focal protrusion of the posterolateral margin of the disk into the foramen, absence of dural sac deformity, and occasionally the presence of c...

Proliferating trichilemmal tumors (PTTs) are neoplasms derived from the outer root sheath of the hair follicle. These tumors, which commonly affect the scalp of elderly women, rarely demonstrate malignant transformation. Although invasion of the tumors into neighboring tissues and being accompanied with anaplasia and necrosis are accepted as findings of malignancy, histological features may not...

We examined the pattern of expression in hair follicles of the transcription factor gene Krox-20. During embryogenesis, Krox-20 is first expressed in the upper portion of the hair bud, then in the hair canal, in the sebaceous glands and in the outer root sheath. In the mature follicles, Krox-20, like Shh and TGFbetaRII, is also expressed in a sub-population of matrix keratinocytes located in a ...

An unusual case of sacral nerve root injury in a boy aged 6 years is described. Surgical intervention was not undertaken. Recovery of function was complete.