Epidermal alterations

Chou et al. (2005) have investigated CS2-induced skin toxicity in mice and alterations in epidermal permeability leading to physiological and pathological changes from topical exposure to CS2. The authors have postulated two mechanistic pathways to account for CS2-induced epidermal alterations, one involving intercellular lipid depletion and the other with keratinocyte damage. 

After 6hours one can already observe more or less extensive epidermal alterations, a moderate infiltrate and a distinct edema of the dermis. 

After 24 and 48 hours we usually observed a moderate acanthosis at the level of the epidermal alterations the infiltrate is moderate. 

Fig. 27. Guinea pig sensitized to DNCB. Nipple irradiated (800 R) and excised 81 hours afterwards no epidermal alterations...

R is administered to the nipple of a sensitized guinea pig before the initiation of the test. Histological examination shows the same epidermal alterations as described above. 

These particular epidermal alterations, observed either on the flank or on the nipple (whether or not irradiation had been carried out before or after the initiation of... 

Fig. 30. a Guinea pig sensitized to DNCB. Acanthosis of the flank (due to X-rays) 14 hours after a single application of O.T ) DNCB in acetone a few epidermal alterations, no spongiosis. b Guinea pig sensitized to DNCB. Acanthosis of the flank (due to crude acid) 14 hours after a single application of 0.1% DNCB in acetone spongiosis... 

Fig. 36. Guinea pig from group one (desensitized) which was resensitized. Flank 14 hours after a single application of 0.1% DNCB in acetone minimal epidermal alterations...

Alteration of Electrical Potential (PD). Study of the Influence of allelochemicals on the electrical potentials across plant cell membranes has been restricted to phenolic acids. Glass and Dunlop (42) reported that at pH 7.2, 500 yM salicylic acid depolarized the electrical potential in epidermal cells of barley roots. The electrical potential changed from -150 mV to -10 mV within 12 min. Recovery of the PD was very slow over about 100 min when the salicylic acid was removed. As the concentration of the allelochemical was increased, the extent of depolarization increased, but the time required for depolarization and recovery were constant. 

Sizemore N and Rorke EA [1993] Human papillomavirus 16 immortalization of normal human ectocervical epithelial cells alters retinoic acid regulation of cell growth and epidermal growth factor receptor expression. Cancer Res 53 4511-4517... 

Eczema does not occur in the absence ofT cells. Here we provide an overview on the regulatory impact which T cells have on the establishment and maintenance of atopic dermatitis. Particularly, we outline the role of different T-helper cell subsets (i.e.Th-l,Th-2,T-regulatory andTh-17 cells) and their distinct influence on the cutaneous inflammatory reaction at different stages of the disease. Eczema is characterized by epidermal inflammation and thus T-cell/ker-atinocyte interactions are of particular relevance in this condition. Alterations in innate and adaptive immunity involving cells result in susceptibility to skin infections and in hyperreactivity reactions to environmental stimuli which in turn determine the course and severity of atopic dermatitis. Copyright 2008 S. Karger AG, Basel... 

With regard to surface molecule expression of keratinocytes and their role in immunoregulation, a recent study by Loser et al. [49] showed that the member of the TNF superfamily, RANKL, is expressed on keratinocytes of inflamed human and mouse skin. In a murine system, RANKL overexpression in keratinocytes resulted in functional alterations of epidermal dendritic cells and systemic... 

Montgomery RB, Guzman J, O Rourke DM, Stahl WL. Expression of oncogenic epidermal growth factor receptor family kinases induces paclitaxel resistance and alters beta-tubulin isotype expression. J Biol Chem 2000 275 17,358-17,363. 

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