Search results for "epidermis"

Chromogranin A in the Mammalian Merkel Cell: Cellular and Subcellular Distribution

1989

Chromogranin-A (CGA), which accounts for more than half the soluble matrix protein in secretory granules of various neuroendocrine cells, has a wide spectrum of potential biological roles and is considered an important marker of the diffuse neuroendocrine system (DNES). Light and electron microscopic immunohistochemistry of mammalian skin revealed that Merkel cells are exclusively CGA-immunoreactive (ir) and that the immunoreaction is localized in the secretory granules. This finding supports the classification of the Merkel cell as a member of the DNES. The CGA immunoreactivity was restricted to Merkel cells of pigs and humans. In human embryonic skin, CGA was expressed in Merkel cells as …

Chapter 20 Multiple messenger candidates and marker substances in the mammalian Merkel cell – axon complex: a light and electron microscopic immunohi…

1988

Publisher Summary This chapter discusses multiple messenger candidates and marker substances in the mammalian merkel cell—axon complex. According to the APUD theory, cells of the diffuse neuroendocrine system (DNES) are essentially characterized by containing amines, peptides and marker substances like neuronspecific enolase (NSE) and chromogranin A (CGA). By the comparison of the histotopography of immunostained peptides, CGA and neuroendocrine markers, there was an expectation to find out the most appropriate immunohistochemical marker of the Merkel cell and to get further insight into the complex chemo-anatomy and possible functional spectrum of the Merkel cell -axon complex at various d…

Embryonic integument and "molts" in Manduca sexta (Insecta, Lepidoptera).

2002

In Manduca sexta the germ band is formed 12 h post-oviposition (p.o.) (=10% development completed) and is located above the yolk at the egg surface. The cells show a polar organization. They are engaged in the uptake and degradation of yolk globules, pinched off from the yolk cells. This process can be observed in the integumental cells during the first growth phase of the embryo that lasts until “katatrepsis,” an embryonic movement that takes place at 40% development completed. At 37% development completed, the ectoderm deposits a thin membrane at its apical surface, the first embryonic membrane, which detaches immediately before katatrepsis. The second period of embryonic growth—from kata…

Sensory performance of blind Mexican cave fish after destruction of the canal neuromasts.

1990

Mixed Epidermal Cell Lymphocyte Reaction: HLA-DR+ Cells Exhibit a Greater Immunostimulatory Activity than CD1a+ Cells

1995

Induction and expression of immunity depends upon processing and presentation of antigens to T-cells by bone marrow derived HLA-DR+ antigen presenting cells (APC). In the induction of immunity to cutaneous antigens, the initial stages of this process begin within the skin itself, and both epidermis and dermis contain bone-marrow derived cells that have the capability of processing and presenting antigens. In normal epidermis, HLA-DR expression is believed to be confined to Langerhans cells with Birbeck granules and indeterminate cells without Birbeck granules. In diseased skin, particularly the inflammatory dermatoses, HLA-DR is commonly expressed by keratinocytes and has been related to th…

Leishmaniasis, contact hypersensitivity and graft-versus-host disease: understanding the role of dendritic cell subsets in balancing skin immunity an…

2010

Dendritic cells (DC) are key elements of the immune system. In peripheral tissues, they function as sentinels taking up and processing antigens. After migration to the draining lymph nodes, the DC either present antigenic peptides by themselves or transfer them to lymph node-resident DC. The skin is the primary interface between the body and the environment and host's various DC subsets, including dermal DC (dDC) and Langerhans cells (LC). Because of their anatomical position in the epidermis, LC are believed to be responsible for induction of adaptive cutaneous immune responses. The functions of LC and dDC in the skin immune system in vivo are manifold, and it is still discussed controvers…

Adenosine A2A and A2B Receptors Differentially Modulate Keratinocyte Proliferation: Possible Deregulation in Psoriatic Epidermis

2017

Adenosine is a potent regulator of inflammation and immunity, but the role of adenosine receptors in keratinocytes remains controversial. We determined that in addition to A2B receptors, human epidermal keratinocytes also express A2A receptors, although to a lower extent. Through the use of selective adenosine receptor agonists and antagonists, we showed that physiological concentrations of adenosine activate A2B receptors in normal human keratinocytes, inducing cell cycle arrest through the increase of intracellular calcium but not through cAMP signaling. In contrast, the selective activation of A2A receptors by CGS-21680 induces keratinocyte proliferation via p38–mitogen-activated protein…

Mammalian Epidermis: A Compendium of Lipid Functionality

2022

Mammalian epidermis is a striking example of the role of lipids in tissue biology. In this stratified epithelium, highly specialized structures are formed that leverage the hydrophobic properties of lipids to form an impermeable barrier and protect the humid internal environment of the body from the dry outside. This is achieved through tightly regulated lipid synthesis that generates the molecular species unique to the tissue. Beyond their fundamental structural role, lipids are involved in the active protection of the body from external insults. Lipid species present on the surface of the body possess antimicrobial activity and directly contribute to shaping the commensal microbiota. Lipi…

Topical application of the adenosine A2Areceptor agonist CGS-21680 prevents phorbol-induced epidermal hyperplasia and inflammation in mice

2014

The nucleoside adenosine is a known regulator of immunity and inflammation that mediates, at least in part, the anti-inflammatory effect of methotrexate, an immunosuppressive agent widely used to treat autoimmune inflammatory diseases. Adenosine A2A receptors play a key role in the inhibition of the inflammatory process besides promoting wound healing. Therefore, we aimed to determine the topical effect of a selective agonist, CGS-21680, on a murine model of skin hyperplasia with a marked inflammatory component. Pretreatment with either CGS-21680 (5 μg per site) or the reference agent dexamethasone (200 μg/site) prevented the epidermal hyperplasia and inflammatory response induced by topica…

Cells of extramammary Paget's disease express cytokeratins different from those of epidermal cells.

1985

The patterns of expression of cytokeratin polypeptides which are closely correlated to routes of differentiation of epithelial cells were studied in extramammary Paget's disease. Cytokeratins of uninvolved and involved epidermis were analyzed by two-dimensional gel electrophoresis of microdissected tissue preparations as well as by immunofluorescence microscopy using cytokeratin antibodies with different specificities. In uninvolved epidermis, cytokeratins Nos. 1, 5, 6, 10, 11, 14, and 16, characteristic of keratinocytes, were found. Epidermis infiltrated by Paget's cells contained the same components and, in addition, cytokeratins Nos. 7, 8, 18, and 19, the latter being characteristic of s…