Search results for "Dermis"
showing 10 items of 202 documents
Pathogenesis of Paraneoplastic Follicular Hyperkeratotic Spicules in Multiple Myeloma
1990
• We describe a 62-year-old man with multiple myeloma who developed horny spicules on his face, particularly on his nose. IgG-λ monoclonal gammopathy was detected, and the serum dysprotein was shown to be a cryoglobulin, which forms a cryogel at low temperatures. Light and electron microscopic and immunohistochemical examinations showed an intercellular precipitation and massive accumulation of the IgG dysprotein and cryoglobulin between the keratinocytes of the upper epidermis and the infundibular epithelium. The follicles were dilated and filled with parakeratotic cells, the protein deposits between them and a rudimentary hair thus resulting in the clinically visible symptoms of horny spi…
Collagen membranes of dermal and pericardial origin-In vivo evolvement of vascularization over time.
2020
Aim of the study was to compare the evolvement of vascularization over time of collagen membranes (CMs) of dermal and pericardial origin in an in vivo animal study. Twenty-eight mice underwent implantation of three commercially available CM derived from porcine dermis (homogenous structure: CM1 (Control 1) and bilayer structure: CM2 [Control 2]), from porcine pericardium (CM3; Test 1) as well as CM3 sprayed with silica-enhanced nanostructured hydroxyapatite (CM4, Test 2). After 3, 6, 9, and 12 days, intravital fluorescence microscopy was conducted for determination of capillary diameter, density, flow, and length. At Day 12, samples were examined immunohistologically for expression of fibro…
Human Epidermal Langerhans Cells Replenish Skin Xenografts and Are Depleted by Alloreactive T Cells In Vivo
2011
Abstract Epidermal Langerhans cells (LC) are potent APCs surveying the skin. They are crucial regulators of T cell activation in the context of inflammatory skin disease and graft-versus-host disease (GVHD). In contrast to other dendritic cell subtypes, murine LC are able to reconstitute after local depletion without the need of peripheral blood-derived precursors. In this study, we introduce an experimental model of human skin grafted to NOD-SCID IL2Rγnull mice. In this model, we demonstrate that xenografting leads to the transient loss of LC from the human skin grafts. Despite the lack of a human hematopoietic system, human LC repopulated the xenografts 6 to 9 wk after transplantation. By…
Fate of autologous dermal stem cells transplanted into the spinal cord after traumatic injury (TSCI)
2003
Rat dermis is a source of cells capable of growing in vitro and, in appropriate conditions, forming floating spheres constituted by nestin-positive cells. We have clonally grown these spheres up to the 15th generation. These spheres can be dissociated into cells that differentiate in vitro under appropriate conditions, these cells are labeled by antibodies to immature neuron markers such as nestin and beta-tubulin III and, later, to mature neuron markers such as microtubule-associated protein 2 and neurofilaments. However, most cells are positive to the astroglial marker glia fibrillary acidic protein (GFAP). When sphere-derived cells are transplanted into the spinal cord after traumatic in…
Factors affecting the intensity of epidermal papillomatosis in populations of roach, Rutilus rutilus (L.), estimated as scale coverage
2006
Studies of epidermal papillomatosis in fish populations have only rarely focused on the intensity of the disease, i.e. the number and size of papillomas. Furthermore, the methods used to evaluate the intensity of papillomatosis have not been standardized. We tested the reliability of a method based on counting of scales covered by papilloma tumours in roach, Rutilus rutilus (L). In addition, we studied the frequency distributions of the number of scales covered by papillomas within populations, evaluated the correlation between the prevalence and mean intensity of the disease among populations and examined the intensity of papillomatosis in roach with respect to sex and size of fish. Reliab…
Wistar rat skin as surrogate for human skin in nortriptyline hydrochloride patch studies
2009
Six different matrices were prepared containing nortriptyline hydrochloride (NTH) with hydroxypropyl-methyl-cellulose as polymer. A mixture of transdermal enhancers was included as part of the vehicle. Diffusion studies were carried out through Wistar rat full thickness skin using Franz cells. They were compared with previously determined human heat separated epidermis in order to test if this animal can be used as model for in vivo assays. A linear correlation was obtained between NTH diffusion coefficients through both skin types (r2=0.996).
Tormogen cell and receptor-lymph space in insect olfactory sensilla. Fine structure and histochemical properties in Calliphora.
1978
(1) The basiconic sensilla on the antennae of Calliphora resemble other insect epidermal sensilla; one or several bipolar sense cells are surrounded by three non-neural cells. (2) The apical cell membrane of the tormogen cell (one of the three accessory cells) forms microvilli coated internally with particles. (3) In the (extracellular) outer receptor-lymph space hyaluronic acid can be demonstrated histochemically. (4) Demonstration of non-specific alkaline phosphatase, Mg2+-activated ATPase, and the presence of mitochondria in the apical part of the tormogen cell suggest active transport processes through these cells into the outer receptor-lymph space.
Immunohistochemical analysis of chromogranin A and multiple peptides in the mammalian Merkel cell: further evidence for its paraneuronal function?
1989
By the use of light microscopic immunohistochemistry, epidermal Merkel cells have been examined for the coexistence of some neuropeptides and chromogranin A (CGA). Peptide and CGA-immunophenotypes were similar in adult Merkel cells but variable in fetal skin, where CGA preceded the expression of peptides which were partly expressed only in a subpopulation of Merkel cells from hair follicles. Thus, only Substance P (SP) and calcitonin gene-related peptide (CGRP) were expressed in a subpopulation of Merkel cells from hair follicles. There were similar Merkel cell densities visualized on consecutive paraffin sections by the use of antisera against peptides, CGA and cytokeratin offering useful …
Matrical carcinoma with prominent melanocytic hyperplasia (malignant melanocytic matricoma?) A report of two cases.
2003
Melanocytic matricoma is a recently described lesion characterized by well-circumscribed nodules composed of matrical and supramatrical cells with clustered ghost cells, and admixed pigmented dendritic melanocytes, with no cyst formation or connection to the epidermis or pre-existing hair follicles. Although variable cytologic atypia and frequent mitoses in the epithelial component may be present, given the well-defined margins and absence of tumor recurrences, these lesions were initially considered benign neoplasms, and not matrical carcinoma. Theoretically, the detection of numerous melanocytes in matrical carcinoma should not be surprising, but is in fact a very unusual feature. A case …
Adenosine A2A receptors in diffuse dermal fibrosis: pathogenic role in human dermal fibroblasts and in a murine model of scleroderma.
2006
Objective Adenosine regulates inflammation and tissue repair, and adenosine A2A receptors promote wound healing by stimulating collagen matrix production. We therefore examined whether adenosine A2A receptors contribute to the pathogenesis of dermal fibrosis. Methods Collagen production by primary human dermal fibroblasts was analyzed by real-time polymerase chain reaction, 14C-proline incorporation, and Sircol assay. Intracellular signaling for dermal collagen production was investigated using inhibitors of MEK-1 and by demonstration of ERK phosphorylation. In vivo effects were studied in a bleomycin-induced dermal fibrosis model using adenosine A2A receptor–deficient wild-type littermate …