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Peripheral Layer (peripheral + layer)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Squamous cell apocrine hidradenoma

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 10 2007
Jorge Angulo
Apocrine hidradenoma is a benign adnexal neoplasm with apocrine differentiation. The neoplasm is composed of four different types of epithelial cells, including pale or clear cells, polygonal cells, mucinous cells and squamous cells, with variable proportions of them from case to case. In most examples of this neoplasm, clear or the polygonal cells are predominant, whereas the other types of neoplastic cells are less abundant. We report two cases of apocrine hidradenoma mostly composed of squamous cells. Histopathologic examination showed that the neoplasms were composed of both solid and cystic areas. The solid aggregations of neoplastic cells were composed of a peripheral layer of basaloid polygonal cells, whereas squamous cells forming the bulk of the aggregations. These squamous cells showed large eosinophilic cytoplasm and vesicular nuclei with prominent nucleoli. In one case, small foci of mucinous cells could also be seen in some aggregations of neoplastic cells, mostly around ductal structures. In both the cases, some of the tubular structures lined by epithelial cells showed evidence of decapitation secretion in their luminal border. The neoplastic stroma consisted of sclerotic collagen bundles when compared with adjacent normal dermis, and artefactual clefts separated the neoplasms from the surrounding tissue. The rare cases described in this report are exceptional because most of the neoplastic cells showed squamous appearance and for that reason we think that squamous cell apocrine hidradenoma is the most appropriate name for these neoplasms. [source]

Immunohistochemical localization of ornithine decarboxylase in skin tumors

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 7 2000
Masayori Kagoura
Background: Ornithine decarboxylase (ODC) plays an important role in the biosynthesis of polyamines. Induction of ODC and polyamine synthesis has been demonstrated in neoplastic tumors and is thought to be related to the degree of malignancy. Methods: In this study, we investigated a series of basal cell epitheliomas (BCE), Bowen's disease, squamous cell carcinomas (SCC), and metastatic tumors of the skin using an antibody against ODC for immunohistochemistry. Results: Eight of 12 cases of BCE failed to show a positive reaction for ODC. In Bowen's disease, 5 of 13 cases diffusely showed positive reaction for ODC. Fourteen of 15 cases of SCC showed ODC expression, the intensity of which was decreased in the peripheral layer. At higher magnification, the distribution of ODC in the positive SCC cases showed granular and heterogenous patterns. Ten of 14 cases of metastatic skin tumors exhibited positive reactions, and well-differentiated adenocarcinomas tended to show more strongly positive than poorly-differentiated ones. Conclusions: These results support the conclusion that the intensity and the incidence of positive immunohistochemical staining for ODC correlate with the degree of cellular differentiation, and furthermore, that heterogenous distribution of ODC staining may be associated with heterogeneity of tumor cells. [source]

Stem cell markers (cytokeratin 15, CD34 and nestin) in primary scarring and nonscarring alopecia

BRITISH JOURNAL OF DERMATOLOGY, Issue 3 2009
M.P. Hoang
Summary Background, Although the pathogenesis of most primary scarring alopecias is poorly understood, recent studies implicate the bulge region as a possible target. Objectives, To corroborate these results, we ascertained involvement of follicular bulge stem cells using a panel of antibodies that putatively targeted the same. Methods, Antibodies used included anticytokeratin (CK) 15, CD34 and nestin on vertical and horizontal tissue sections of 50 cases of scarring and 34 cases of nonscarring alopecia. Results, Comparing expression of these markers in scarring vs. nonscarring alopecia, CK15 was noted in the follicular bulge region in 23 of 43 (53%) vs. 27 of 27 (100%) cases and in the peripheral layer of the outer root sheath (ORS) (upper two-thirds of the follicle) in 50 of 50 (100%) vs. 34 of 34 (100%) cases; CD34 was noted in the peripheral layer of the ORS (below pilar muscle attachment) in 24 of 35 (69%) vs. 18 of 18 (100%) cases; and nestin was noted in the infundibular region in 18 of 46 (39%) vs. seven of 32 (22%) cases and in the inner aspect of the ORS (below pilar muscle attachment) in eight of 31 (26%) vs. 23 of 23 (100%) cases. Conclusions, Our findings of differential follicular localization of stem cells underscore follicular progenitor cell heterogeneity and suggest the target in scarring alopecia is not merely follicular bulge stem cells but involves stem cells in the inner and outer aspect of the ORS. Enhanced expression of nestin in the infundibular region in scarring alopecia indicates availability of an accessible, in vivo niche of potential utility as an autologous source of stem cells for therapeutic application. [source]

Modeling of structural reaction injection molding process.

POLYMER ENGINEERING & SCIENCE, Issue 5 2001

A mathematical model of the infusion process in producing reinforced articles is proposed. The model is based on the analysis of flow of a Newtonian liquid inside a rectangular multilayer channel. According to the model, a liquid enters the central (feeding) layer, moves through this layer, and simultaneously impregnates peripheral layers. So, the flow is two-dimensional. Flow inside the porous layers is treated in terms of the Darcy equation with different permeability coefficients in two directions. Principal solutions for the flow front development and pressure evolution were obtained and analyzed. Then the initial model, developed for a Newtonian liquid, is generalized for the so-called "rheokinetic" liquid, which changes its rheological properties in time as a result of temperature variation and/or any possible chemical process, in particular, the reaction of curing of a binder. It was proven that in this case the solution is automodel. This means that the solutions obtained for a Newtonian liquid in the dimensionless form are valid for an arbitrary rheokinetic liquid. [source]