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Basal Epidermis (basal + epidermis)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	50%

Selected Abstracts

Id2, Id3, and Id4 proteins show dynamic changes in expression during vibrissae follicle development

DEVELOPMENTAL DYNAMICS, Issue 6 2008
Nigel L. Hammond
Abstract Id proteins are involved in the transcriptional control of many fundamental biological processes, including differentiation and lineage commitment. We studied Id2, Id3, and Id4 protein expression during different stages of rat vibrissa follicle development using immunohistochemistry. Id2 was highly expressed in the cytoplasm of specialized cells in the basal epidermis and outer root sheath during early stages of follicle development. These cells were identified as Merkel cells (MCs) by means of double-immunolabeling with synaptophysin and cytokeratin-20, and persisted in neonatal follicles. Id3 immunofluorescence was characterized by membrane-associated expression in basal epithelial cells of follicles early in development. Subsequently follicle epithelial cells switched to have strong nuclear labeling, also a feature of newly forming dermal papilla cells. Id4 expression was primarily associated with innervation of the developing follicle musculature. These observations illustrate dynamic expression patterns of Id2 and Id3 proteins in developing follicles and specifically link Id2 expression to Merkel cell specification. Developmental Dynamics 237:1653,1661, 2008. © 2008 Wiley-Liss, Inc. [source]

Paraneoplastic pemphigus/paraneoplastic autoimmune multiorgan syndrome

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2 2009
FNASC, FRAS(LOND.), Virendra N. Sehgal MD
Paraneoplastic pemphigus is the term used for an exclusive subset of pemphigus. The clinical lesions may resemble pemphigus, pemphigoid, erythema multiforme, graft-vs.-host disease, or lichen planus. A common denominator in all patients is the concomitant occurrence of either occult or confirmed systemic neoplasm. It is imperative to confirm the diagnosis through microscopy, where intraepidermal suprabasal cleavage, epidermal acantholysis, dyskeratotic keratinocytes and vacuolar changes in the basal epidermis, interfacial dermatitis, and epidermal exocytosis can be seen. Furthermore, the deposition of immunoglobulin G (IgG) and complement in the epidermal intercellular spaces, detected by direct and/or indirect immunofluorescence, is equally crucial for confirming the diagnosis. [source]

Ultrastructure of the embryonic snake skin and putative role of histidine in the differentiation of the shedding complex

JOURNAL OF MORPHOLOGY, Issue 2 2002
Lorenzo Alibardi
Abstract The morphogenesis and ultrastructure of the epidermis of snake embryos were studied at progressive stages of development through hatching to determine the time and modality of differentiation of the shedding complex. Scales form as symmetric epidermal bumps that become slanted and eventually very overlapped. During the asymmetrization of the bumps, the basal cells of the forming outer surface of the scale become columnar, as in an epidermal placode, and accumulate glycogen. Small dermal condensations are sometimes seen and probably represent primordia of the axial dense dermis of the growing tip of scales. Deep, dense, and superficial loose dermal regions are formed when the epidermis is bilayered (periderm and basal epidermis) and undifferentiated. Glycogen and lipids decrease from basal cells to differentiating suprabasal cells. On the outer scale surface, beneath the peridermis, a layer containing dense granules and sparse 25,30-nm thick coarse filaments is formed. The underlying clear layer does not contain keratohyalin-like granules but has a rich cytoskeleton of intermediate filaments. Small denticles are formed and they interdigitate with the oberhautchen spinulae formed underneath. On the inner scale surface the clear layer contains dense granules, coarse filaments, and does not form denticles with the aspinulated oberhautchen. On the inner side surface the oberhautchen only forms occasional spinulae. The sloughing of the periderm and embryonic epidermis takes place in ovo 5,6 days before hatching. There follow beta-, mesos-, and alpha-layers, not yet mature before hatching. No resting period is present but a new generation is immediately produced so that at 6,10 h posthatching an inner generation and a new shedding complex are forming beneath the outer generation. The first shedding complex differentiates 10,11 days before hatching. In hatchlings 6,10 h old, tritiated histidine is taken up in the epidermis 4 h after injection and is found mainly in the shedding complex, especially in the apposed membranes of the clear layer and oberhautchen cells. This indicates that a histidine-rich protein is produced in preparation for shedding, as previously seen in lizard epidermis. The second shedding (first posthatching) takes place at 7,9 days posthatching. It is suggested that the shedding complex in lepidosaurian reptiles has evolved after the production of a histidine-rich protein and of a beta-keratin layer beneath the former alpha-layer. J. Morphol. 251:149,168, 2002. © 2002 Wiley-Liss, Inc. [source]

Percutaneous application of peptidoglycan from Staphylococcus aureus induces an increase in mast cell numbers in the dermis of mice

CLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2005
K. Matsui
Summary Background Atopic dermatitis (AD) is a chronic inflammatory skin disease with immunopathologic features that vary depending on the duration of the lesion. The dermis of lesional skin of AD patients shows an increased number of inflammatory cells such as mast cells, eosinophils and mononuclear cells and superficial Staphylococcus aureus colonization. Objective The purpose of this study was to determine the effects of peptidoglycan (PEG) from S. aureus on mast cell induction in murine skin. Methods PEG was applied to barrier-disrupted abdominal skin of mice every 5 days and the number of mast cells in the abdominal skin was counted 20 days after the first application. The cytokine response was investigated by RT-PCR and immunohistologic analysis. Results The number of mast cells in the skin of mice treated with PEG was increased significantly compared with that of mice given phosphate-buffered saline. In addition, application of PEG to the abdominal skin increased the expression of mRNA for transforming growth factor-,1 (TGF-,1), which supports mast cell migration, but not that for IL-3 or stem cell factor, which support both mast cell proliferation and mast cell migration. Immunohistologic analysis demonstrated that levels of TGF-,1 transcripts corresponded with those of protein synthesis in the epidermis. TGF-,1 was found to be highly expressed in keratinocytes of the basal epidermis of PEG-treated skin. Furthermore, intraperitoneal injection of anti-TGF-,1 antibodies neutralized the induction of mast cells into the skin. Conclusion These results suggest that PEG may have the ability to induce an increase in mast cell numbers in the skin through TGF-,1 production by epidermal keratinocytes. Skin inflammation might therefore be linked to colonization with S. aureus in AD patients. [source]