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  • 1
    Electronic Resource
    Electronic Resource
    Human stratum corneum polar lipids and desquamation (1985)
    Springer
    Archives of dermatological research 277 (1985), S. 284-287 
    Details
    ISSN: 1432-069X
    Keywords: Desquamation ; Epidermal lipids ; Ceramides ; Cholesteryl sulfate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ceramides and steryl-sulfate components from desquamated and cohesive human stratum corneum were examined using a combination of chemical and chromatographic means. Six structurally distinct series of ceramides were identified, and the relative amounts of these species, as measured by quantitative thin-layer chromatography, did not differ in cohesive and desquamated stratum corneum. In contrast, the level of cholesteryl sulfate was significantly reduced in the desquamated material. The results are in accord with the hypothesis that cholesteryl sulfate serves in cell-to-cell cohesion within the stratum corneum, and its hydrolysis may be necessary to permit shedding of cells from the surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00509081
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Analysis of hair lipids and tensile properties as a function of distance from scalp (2005)
    Oxford, UK : Blackwell Science Ltd
    International journal of cosmetic science 27 (2005), S. 0 
    Details
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Cuticle cells form the outer covering surrounding and protecting the cortex. The cuticle cells are thin, flat and overlap, and intercellular lipid lamellae are found in the gaps between the cell boundaries. The lipid lamellae are also found within the cortex in the cell boundaries between the long fribrous corticle cells. In addition, the outer surfaces of the cuticle cells are covered by a monolayer of covalently bound fatty acids, a major component of which is 18-methyleicosanoic acid. The fatty acids are thought to be attached through thio-ester linkages. Together these lipids are thought to be major determinants of the physical properties of the hair. The present study tested the hypothesis that both free and covalently bound lipids are progressively lost during normal environmental exposures. This progressive loss within the cuticle layers may, in part, lead to an increased susceptibility of the protein and lipid lamellae in the cortex to degradation. This degradation, in turn, would contribute to a progressive decrease in the tensile properties of the hair. Research grade hair was cut into five segments from the root to the distal end. Lipids from each segment were extracted and analyzed by thin-layer chromatography in conjunction with photodensitometry. The major free polar lipid classes in the hair included ceramides, glucosylceramides and cholesterol sulfate. The concentrations of all of the free polar lipids as well as the covalently bound fatty acids decreased in going from the root to the distal end of the hair. In addition, there was a significant reduction in tensile properties of the hair from the root to distal end. In conclusion, the progressive loss of endogenous free and covalently bound lipids from hair, which are probably related to normal weathering of the hair and grooming practices, may help contribute to a marked decrease in tensile properties to the hair.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1467-2494.2005.00236.x
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Prostaglandin E2 and interleukin-1 levels in smokeless tobacco-induced oral mucosal lesions (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 29 (1994), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Inflammatory mediators released as a result of smokeless tobacco (ST)-induced irritation may play a role in the development of oral mucosal lesions at habitual tobacco placement sites in ST users. The present study examined levels of interleukin-1 (IL-1) and prostaglandin E2 (PGE2) in ST-induced mucosal lesions and compared these to mediator levels in clinically normal mucosa. Soft tissue biopsies were obtained from white mucosal lesions at habitual placement sites and normal alveolar mucosal tissue at non-placement sites in 18 ST users. Fifteen non-tobacco using subjects also provided normal alveolar mucosal biopsies. IL-1 and PGE2 were recovered from the specimens, and mediator levels were determined by enzyme immunoassay. Prostaglandin E2 levels (pg/mg) were lower in both regions in the ST subjects, but values did not vary significantly between the regions with 2.77±0.72 and 2.86±0.99 at placement and non-placement sites, respectively, in ST users and 7.31±3.84 in non-tobacco users. Both IL-1α and IL-lβ (pg/mg) were significantly (p 〈 0.0I) elevated in ST lesions (IL-lã=25.56±4.00; IL-1β=7.76±1.68) compared to either non-placement sites in ST users (IL-lα=14.64±2.65; IL-lβ=1.63±0.72) or non-tobacco users (IL-lα=12.84±2.60; IL-lβ=2.04±0.75). In view of IL-l's role in keratinocyte proliferation and its inflammatory effects, this cytokine may contribute to mucosal and gingival alterations observed in ST users.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.1994.tb01245.x
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  • 4
    Electronic Resource
    Electronic Resource
    Penetration of N-nitrosonornicotine (NNN) across oral mucosa in the presence of ethanol and nicotine (2000)
    Copenhagen : Munksgaard International Publishers
    Journal of oral pathology & medicine 29 (2000), S. 0 
    Details
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The effects of ethanol concentrations of 5, 15, 20, 25, 27, 30 and 50% on the penetration of the tobacco-specific carcinogen, nitrosonornicotine (NNN), across porcine oral mucosa were examined using an in vitro perfusion system. Concentrations of ethanol of 25% and above significantly increased the permeability of oral mucosa to NNN, although this increase ceased with 50% ethanol, possibly due to a fixative effect. Nicotine is a consistent component of smoked and smokeless tobacco; the presence of 0.2% nicotine significantly increased the permeability of oral mucosa to NNN and 2% nicotine caused a further increase. Combined use of nicotine and ethanol significantly increased the penetration of NNN across oral mucosa over that of ethanol alone until the concentration of ethanol reached 50%. The results of this study suggest that the synergy between tobacco and alcohol in the etiology of oral cancer may be explained, at least in part, by the local permeabilizing effects of alcohol on the penetration of tobacco-specific (and other) carcinogens across oral mucosa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-0714.2000.290205.x
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Isolation of corneocyte envelopes from porcine epidermis (1988)
    Springer
    Archives of dermatological research 280 (1988), S. 424-429 
    Details
    ISSN: 1432-069X
    Keywords: Stratum corneum ; Detergent extraction ; Corneocyte envelopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sheets of porcine stratum corneum were dispersed into individual corneocytes after 4 h in a solution consisting of 8 mM N,N-dimethyldodecylamine oxide and 2 mM sodium dodecylsulfate in phosphate-buffered isotonic saline, at 45°C. With continued detergent treatment and moderate sonication, most of the cells lost their keratin contents and were then separated from the remaining intact cells by centrifugation in cesium chloride solution of density 1.280. Electron microscopy showed that the cell envelopes retained both the cross-linked protein envelope and its attached lipid envelope. The dry weight of envelopes was approximately 7% of the estimated dry weight of the original stratum corneum, while the corneocytes surviving intact also amounted to 7% of the starting weight. Mild alkaline hydrolysis of the corneocyte envelopes allowed the extraction of hydroxyceramides amounting to 10% of the dry weight of the envelopes. The procedure therefore provides isolated corneocyte envelopes suitable for studying both the protein and lipid components of this compound sheath.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429982
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  • 6
    Electronic Resource
    Electronic Resource
    Organization of the intercellular spaces of porcine epidermal and palatal stratum corneum: a quantitative study employing ruthenium tetroxide (1995)
    Springer
    Cell & tissue research 279 (1995), S. 271-276 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Desmosomes ; Lipid ; Membrane permeability ; Oral mucosa ; Epidermis ; Palate ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Previous studies have demonstrated that the intercellular spaces of the stratum corneum contain multilamellar lipid sheets with variable ultrastructure in addition to desmosomes or desmosomal remnants. The intercellular lamellae are thought to provide a permeability barrier whereas the desmosomes are responsible for cell-cell cohesion. In this study, transmission electron microscopy of RuO4-fixed tissue was used to compare the proportions of the intercellular spaces in epidermal and palatal stratum corneum occupied by desmosomes and by different patterns of lamellae. Desmosomes are more abundant in palatal than in epidermal stratum corneum (46.9 vs 15.0% length of intercellular space). In epidermis the most frequent lamellar arrangements involve 3 (23.5%) or 6 (24.2%) lucent bands with an alternating broad-narrow-broad pattern, whereas the most frequent lamellar arrangements in palatal tissue are 2 (17.2%) or 4 (10.5%) lucent bands of uniform width. Most of the nondesmosomal portion of the intercellular space in palatal stratum corneum was dilated and had elongated lamellae at the periphery and short disorganized lamellae and amorphous electron-dense material in the interior. It is concluded that the multilamellar lipid sheets are less extensive in palatal than in epidermal stratum corneum, which could explain the greater permeability of the palate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050282
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  • 7
    Electronic Resource
    Electronic Resource
    Organization of the intercellular spaces of porcine epidermal and palatal stratum corneum: a quantitative study employing ruthenium tetroxide (1995)
    Springer
    Cell & tissue research 279 (1995), S. 271-276 
    Details
    ISSN: 1432-0878
    Keywords: Desmosomes ; Lipid ; Membrane permeability ; Oral mucosa ; Epidermis ; Palate ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Previous studies have demonstrated that the intercellular spaces of the stratum corneum contain multilamellar lipid sheets with variable ultrastructure in addition to desmosomes or desmosomal remnants. The intercellular lamellae are thought to provide a permeability barrier whereas the desmosomes are responsible for cell-cell cohesion. In this study, transmission electron microscopy of RuO4-fixed tissue was used to compare the proportions of the intercellular spaces in epidermal and palatal stratum corneum occupied by desmosomes and by different patterns of lamellae. Desmosomes are more abundant in palatal than in epidermal stratum corneum (46.9 vs 15.0% length of intercellular space). In epidermis the most frequent lamellar arrangements involve 3 (23.5%) or 6 (24.2%) lucent bands with an alternating broad-narrow-broad pattern, whereas the most frequent lamellar arrangements in palatal tissue are 2 (17.2%) or 4 (10.5%) lucent bands of uniform width. Most of the nondesmosomal portion of the intercellular space in palatal stratum corneum was dilated and had elongated lamellae at the periphery and short disorganized lamellae and amorphous electron-dense material in the interior. It is concluded that the multilamellar lipid sheets are less extensive in palatal than in epidermal stratum corneum, which could explain the greater permeability of the palate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318483
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    Paper (German National Licenses)
    Fulltext
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