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  • 1
    Electronic Resource
    Electronic Resource
    Layer-by-layer transitions in liquid crystals (1995)
    Springer
    International journal of thermophysics 16 (1995), S. 33-43 
    Details
    ISSN: 1572-9567
    Keywords: free-standing film ; heat capacity ; layer-by-layer transition ; liquid crystal ; smectic-A hexatic-B transition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Employing our free-standing film calorimetric system. we have identified three remarkable layer-by-layer transitions in several liquid crystal compounds. Each of these transitions can be well described by the simple power-law form:L = L 0 t. The layering transitions liMind near the smectic-A- hexatic-B and smectic-A crystal-B transitions are well characterized by the exponent v≈ 1 3. This value is consistent with models based on a van der Wads-like dominant intermolecular interaction. Another novel layer-by-layer thinning transition has been discovered above the hulk smectic-A isotropic transition of a perfluorinated liquid crystal compound. The value of the exponent obtained, v ≈ 3 4. cannot he easily explained using familiar models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01438955
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  • 2
    Electronic Resource
    Electronic Resource
    Platelet-derived growth factor in middle ear cholesteatoma (1994)
    Springer
    European archives of oto-rhino-laryngology and head & neck 251 (1994), S. 199-204 
    Details
    ISSN: 1434-4726
    Keywords: Cholesteatoma ; Platelet-derived growth factor ; Keratinocyte ; Bone resorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Platelet-derived growth factor (PDGF) was localized in human middle ear cholesteatoma tissue by an immunoperoxidase technique using rabbit anti-human PDGF IgG. PDGF was found mainly in basal cells and in granulation tissue, and especially involved monocytes and fibroblast-like cells. The external ear canal epithelium was not significantly stained by anti-human PDGF. Findings demonstrate that the presence of PDGF in cholesteatoma is in response to inflammation and wound healing in the middle ear. PDGF in vitro was found to stimulate protein synthesis and cellular terminal differentiation of basal keratinocytes. PDGF also stimulated monocytes to form multinucleated osteoclast-like cells. These multinucleated cells, in turn, induced the resorption of devitalized bovine bone. This bone resorption was seen in co-cultures of osteoblasts and multinucleated osteoclast-like cells in the presence of PDGF, suggesting that cell-to-cell interaction plays a role in bone resorption. The present study suggests that PDGF takes part in the clinical development and the destructive effect of cholesteatoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00628423
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  • 3
    Electronic Resource
    Electronic Resource
    Heat capacity measurements of extremely thin substrate-free liquid-crystal films (1994)
    Springer
    International journal of thermophysics 15 (1994), S. 1189-1197 
    Details
    ISSN: 1572-9567
    Keywords: calorimeter ; density ; film ; heat capacity ; hexatic ; liquid crystal ; smectic-A-hexatic-B transition ; two-dimensional melting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A state-of-the-art calorimetric system has been established. The system enables us to measure simultaneously heat capacity and optical reflectivity of free-standing liquid-crystal films from many hundreds down to only two molecular layers in thickness. Our experimental results on the smectic-A-hexatic-B and smectic-C-smectic-I transitions cannot be described solely in terms of the creation of bond-orientational order, indicating that additional molecular order must be present in the hexatic phases of liquid crystals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01458827
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  • 4
    Electronic Resource
    Electronic Resource
    The effect of endotoxin and prostaglandin E2 on the proliferation of keratinocytes in vitro (1986)
    Springer
    European archives of oto-rhino-laryngology and head & neck 243 (1986), S. 211-214 
    Details
    ISSN: 1434-4726
    Keywords: Keratinocytes ; Endotoxin ; Prostaglandin E2 ; Infection ; Cholesteatoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Since the rate of epidermal basal cell proliferation appears to be a crucial factor in the development of acquired cholesteatoma, we studied the effect of prostaglandin E2 (PGE2) and endotoxin on the growth of keratinocytes. PGE2 and endotoxins are inflammatory mediators in chronic otitis media. Various concentrations of endotoxin and PGE2 were added to keratinocytes derived from newborn rats. The synthesis of DNA was then studied by incorporation of 3H-thymidine into the keratinocytes. We found that either endotoxin or PGE2 alone inhibited DNA synthesis by keratinocytes, while endotoxin (10 μg/ml) and PGE2 (10 ng/ml) together stimulated DNA synthesis by keratinocytes. These findings suggest that inflammatory mediators, such as endotoxin plus PGE2, in chronic otitis media stimulate the growth of epidermal basal cells of cholesteatoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00470624
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  • 5
    Electronic Resource
    Electronic Resource
    Localization of intercellular adhesion molecule-1 in middle ear cholesteatoma (1995)
    Springer
    European archives of oto-rhino-laryngology and head & neck 252 (1995), S. 385-390 
    Details
    ISSN: 1434-4726
    Keywords: Cholesteatoma ; Intercellular adhesion molecule ; Interleukin-1 ; Tumor necrosis factor-alpha
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Intercellular adhesion molecule-1 (ICAM-1) may have a role in acquired cholesteatoma, which is usually associated with an inflammatory reaction occurring in the middle ear cavity. The presence of ICAM-1 in human cholesteatomas was demonstrated by an immunoblotting assay using a specific monoclonal anti-ICAM-1 antibody after protein extraction. Distribution of ICAM-1 in the cholesteatoma tissues was then studied by avidin-biotin-peroxidase complex staining. ICAM-1 appeared to be localized on keratinocytes in all layers of the epithelium and on Langerhans cells in both the epithelium and granulation tissue of cholesteatoma. ICAM-1 was not found in the epidermis of normal external ear canal skin, normal tympanic membrane or normal facial skin, but significant staining was seen on keratinocytes of hair follicles and glands in the facial skin. The present study is the first to demonstrate ICAM-1 in cholesteatoma and suggests that it may have an important role in the clinical development of cholesteatoma, including migration, adhesion and proliferation of lymphocytes, Langerhans cells and keratinocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00167306
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  • 6
    Electronic Resource
    Electronic Resource
    Langerhans cells in human middle ear cholesteatomas (1992)
    Springer
    European archives of oto-rhino-laryngology and head & neck 249 (1992), S. 380-384 
    Details
    ISSN: 1434-4726
    Keywords: Cholesteatoma ; Langerhans cells ; Basal cells ; T-lymphocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Langerhans cells have been found in cholesteatomas for many years. It is believed that they are immunocompetent cells and have the same role in cell-mediated immunologic mechanisms in cholesteatoma as well as in skin. This study used the transmission electron microscope to observe the cellular characteristics of Langerhans cells and the apposition phenomenon of Langerhans cells with lymphocyte-like cells in human middle ear cholesteatomatous tissue. These findings are evidence for cell-mediated immune responses in middle ear cholesteatomas. In vitro Langerhans cells conditioned medium prepared from Lewis rat skin was used to show its effects on protein synthesis and the differentiation of basal cells. Since the cellular behaviour of basal cells is important in the development and pathogenesis of cholesteatoma, the present study shows that Langerhans cells may have some role in the clinical formation of a cholesteatoma. Since cells extracted from rat skin may have a different response from that of cells from human middle ear cholesteatoma, further investigations are necessary to compare the biological effects of both tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192258
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  • 7
    Electronic Resource
    Electronic Resource
    Localization of fibronectin in human middle ear cholesteatoma (1988)
    Springer
    European archives of oto-rhino-laryngology and head & neck 245 (1988), S. 160-165 
    Details
    ISSN: 1434-4726
    Keywords: Fibronectin ; Basal cell ; Cholesteatoma ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fibronectin was localized in human cholesteatoma tissues by immunohistochemical methods. The avidin-biotin-peroxidase complex staining method was used with specific fibronectin antibody. Fibronectin appeared to be localized in the matrix of the cholesteatoma studied, particularly on the surface of the cell membranes and the nuclei of the basal cells and in connective tissue. Fibronectin was not seen in the granular layer or in the keratin area. Fibronectin was found on the surface of granulation tissue, mononuclear cells, fibroblasts and endothelial cells of blood vessels. These findings were confirmed by the immunofluorescent staining method. Our previous study showed that fibronectin induced a migration of keratinocytes, macrophages and fibroblasts demonstrated by the Boyden's chamber chemotaxis assay. Macrophages and fibroblasts were shown to produce collagenase, a bone resorption factor, in cholesteatomatous tissue. The present study showed the presence of fibronectin in the matrix of cholesteatoma and granulation tissue, suggesting that fibronectin might play an important role in the clinical development and invasive behavior of cholesteatoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464019
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of granulation tissue conditioned medium on the in vitro differentiation of keratinocytes (1988)
    Springer
    European archives of oto-rhino-laryngology and head & neck 245 (1988), S. 325-329 
    Details
    ISSN: 1434-4726
    Keywords: Cholesteatoma ; Terminal differentiation ; Transglutaminase ; Cell envelope
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The accumulation of desquamated keratinizing squamous epithelial cells appears to be a crucial factor in the pathogenesis of middle ear cholesteatomas. The accumulation of keratin debris is due to the proliferation and the terminal differentiation of basal keratinocytes. Since cholesteatomas are usually associated with inflammatory reactions in the middle ear cavity, we examined the effects of a granulation tissue conditioned medium on the terminal differentiation of basal keratinocytes in vitro. This conditioned medium stimulated the terminal differentiation of basal keratinocytes by showing: (a) increased incorporation of 3H-leucine into cell envelopes; (b) an increased number of SDS-insoluble cell envelopes; and (c) increased transglutaminase activity (as a marker for terminal cellular differentiation). Our present studies further suggest that inflammatory granulation tissue plays an important role in the clinical growth and development of the cholesteatoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00457987
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  • 9
    Electronic Resource
    Electronic Resource
    An immunocytochemical study of cytokeratin expression in human middle ear cholesteatoma (1989)
    Springer
    European archives of oto-rhino-laryngology and head & neck 246 (1989), S. 37-42 
    Details
    ISSN: 1434-4726
    Keywords: Cholesteatoma ; Cytokeratin ; Intermediate filaments ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An indirect immunofluorescent method with monoclonal anti-cytokeratin antibodies was used to localize various cytokeratins in human middle ear cholesteatoma. The 50 K/58 K and 56.5 K/65–67 K paired cytokeratins are markers of skin type and were found in the specimens of human middle ear cholesteatomas studied. In contrast, the 40 K and 45 K cytokeratins (markers of simple epithelia), the 48 K cytokeratin (marker of hyperproliferative epidermal disease) and the 51K cytokeratin (marker of internal organ epithelia) were absent in human middle ear cholesteatoma. These findings indicate that the pattern of cytokeratins in human middle ear cholesteatoma is similar to that of skin but is different from those of simple epithelium, internal organ epithelia, and hyperproliferative epidermal disease. These findings also support the skin type epithelial origin of cholesteatoma and strongly favor the migration theory in the genesis of cholesteatomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454132
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  • 10
    Electronic Resource
    Electronic Resource
    Mediation of signal transduction in keratinocytes of human middle ear cholesteatoma byras protein (1996)
    Springer
    European archives of oto-rhino-laryngology and head & neck 253 (1996), S. 385-389 
    Details
    ISSN: 1434-4726
    Keywords: Cholesteatoma ; Ras protein ; Signal transduction ; Growth factor receptors ; Transcription factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Immunolocalization was used to investigate the distribution of ras protein in both congenital and acquired cholesteatoma tissues. A pathological feature of middle ear cholesteatoma included accumulation of keratin debris due to active proliferation and differentiation of keratinocytes. Ras protein localized to the inner plasma membrane and cytoplasm of keratinocytes in all of the epithelial layers in both congenital and acquired cholesteatoma specimens. Keratinocytes in the basal layer were stained more intensely than their differentiated counterparts. Findings also demonstrated that receptors for epidermal growth factor, fibroblast growth factor, and plateletderived growth factor were present in the plasma membrane of keratinocytes. C-jun, a transcription factor was found in the nuclei of keratinocytes of the cholesteatoma epithelium. These findings indicate that ras protein plays a pivotal role in a signal transduction cascade between growth factor receptors in the plasma membrane and the transcription factor, c-jun, in the nuclei of keratinocytes during the growth of cholesteatoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00168488
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