Desquamated epithelial cells

The external auditory canal skin is normally acidic, with a pH level between 4 and 5. Keratin, which consists of desquamated epithelial cells, is produced by the epithelial (skin) lining of the external ear canal it has an isoelectric point of pH 5. Any increase above this value causes hydration of the keratin layer, increasing susceptibility to pathogenic organisms. Because as most organisms responsible for otitis... 

Fecal zinc is derived from unabsorbed dietary zinc and zinc in desquamated epithelial cells and gastrointestinal secretions. Active intestinal secretion of zinc decreases in zinc-depleted animals and may be a regulated step in zinc homeostasis. 

Each day, approximately 1 mg Fe is lost from the body via desquamated epithelial cells from the gastrointestinal treact, the skin and the urinary tract (Green et al. 1968). This corresponds to 0.025% of the body s iron stores, leading to a half-life for body iron of over 6 years if blood losses are not considered. Excess iron cannot be excreted on demand. 

Urinary lipid excretion occurs mainly in the form of vacuolated cells (Sibley 1918, Fessas et al. 1955, Pittelkow 1955, Yu 1956, Dempsey et al. 1965) which resemble macrophages some free lipid droplets are also found (Fessas et al. 1955, Wachtel and Mattei 1964, Kalkoff 1966). According to Ruiter (1958) the lipid-laden cells are desquamated epithelial cells of the loop of Henle. 

It is a lipophilic compound which removes intercellular lipids that are covalently linked to the cornified envelope surrounding epithelial cells [3]. It also enhances penetration of other agents. Resorcinol (m-dihydroxy benzene) is structurally and chemically similar to phenol. It disrupts the weak hydrogen bonds of keratin [4]. Lactic acid is an alpha hydroxy acid which causes corneocyte detachment and subsequent desquamation of the stratum corneum [5]. 

The prediction of such hot spots of gas transfer at bifurcations is supported by experimental data on ozone-exposed rabbits. Longitudinal slices of airways from these rabbits showed at low magnification that desquamation of the ciliated epithelial cells was focal and sometimes more intense at a bifurcation. 

In experimental animals the respiratory system is a primary target of acrolein exposure after inhalation, and there is an inverse relationship between the exposure concentration and the time it takes for death to occur." Inhalation LCso values of 327ppm for 10 minutes and 130ppm for 30 minutes have been reported in rats." Of 57 male rats, 32 died after exposure to 4 ppm for 6 hours/day for up to 62 days. Desquamation of the respiratory epithelium followed by airway occlusion and asphyxiation is the primary mechanism for acrolein-induced mortality in animals." Sublethal acrolein exposure in mice at 3 and 6 ppm suppressed pulmonary antibacterial defense mechanisms. A combination of epithelial cell injury and inhibition of macrophage function may be responsible for acrolein-induced suppression of pulmonary host defense. ... 

Mustard initially causes vasodilation and increased vascular permeability in the conjunctiva, which lead to progressive edema. Secretion of mucus occurs within minutes of exposure. Pyknosis of epithelial cells begins concurrently with or shortly after these changes, leading to desquamation of the epithelium. In the later stages, inflammatory infiltration of connective tissue and exudation are present (Warthin and Weller, 1919 Maumenee and Scholz, 1948). Medical personnel have reported seeing delayed keratitis in humans from as little as 8 months to 20 years after mustard exposure (Mann and Pullinger, 1944 Atkinson, 1948). This delayed keratitis, in addition to the chronic inflammation, can lead to erosions and frank ulcerations. 

Dose-related effects were noted in guinea pig skin that was treated with a 25x25 mm square 90Sr source (Etoh et al. 1977). At 1,000 rad, there was a transient 25% reduction in the number of basal epithelial cells by day 10, that approached normality by day 15. At 2,200 rad, the epithelial basal cell population dropped by about 60% at day 12, but was slightly above normal by day 20. At 3,000 and 5,000 rad, the basal epithelial cell population was reduced 75%, but hyperplasia was also detected at the margin of the field. Hyperplasia was maintained for the 50-day observation period following exposure to 2,200-5,000 rad. At 3,000 rad, erythema was noted by day 14, followed by dry desquamation and complete hair loss by day 21. A similar pattern, with ulceration at 1 month, was seen at 5,000 rad. 

Lesions were prominent at the corticomedullary junction where abrasion of the brush border of the tubular epithelium and desquamation of tubular epithelial cells were commonly seen. This tubular injury was associated with increased blood urea nitrogen levels and enhanced urinary excretion of endopeptidase 24.11 [156], an enzyme of the brush border of the proximal tubular epithehum. 

Salicylic acid is irritating to skin and mucosa and destroys epithelial cells. The keratolytic action of the free acid is employed for the local treatment of warts, corns, fiingal infections, and certain types of eczematous dermatitis. After treatment with salicylic acid, tissue cells swell, soften, and desquamate. Methyl salicylate foil of wintergreenj is used topically as a counter-irritant for the relief of mild musculoskeletal pain. 

The defect in mucopolysaccharide synthesis together with the increased incorporation of methionine sulfur and the decreased cystine content may reflect an increased epithelial cell turnover, as suggested by the hyperplastic mucosa and the masses of epithelial cells in the biliary tract, but the picture is not yet complete. In any case, it is clear that desquamated cells appear to be the most important factor in this form of cholelithiasis. The contribution of cellular debris to other types of gallstone formation has been discussed in previous sections. 

In rats, inhaled plutonium caused proliferation, desquamation, and clearance of type II epithelial cells out to the ciliated bronchioles (Sanders et al. 1971). In baboons, that were 3-times as sensitive as... 

Some form of local desquamation of intestinal epithelium seems to be the most common explanation of how particles, of any size, might be absorbed via the usually tight junctions between epithelial cells (Luckey, 1974 Csaky, 1984). One hypothesized mechanism for the extrusion of epithelial cells is a combination of the pressure from reproducing epithehal cells, which loosens the surrounding cells, and variations in lymphatic pressure in the lacteals acting on the epithelium. A decrease in lymphatic pressure could then, in theory, draw particulate matter into the site through... 

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