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  • 1
    Electronic Resource
    Electronic Resource
    A morphometric study of alterations in rough endoplasmic reticulum during differentiation in stratified squamous epithelium (1984)
    Springer
    Archives of dermatological research 276 (1984), S. 303-312 
    Details
    ISSN: 1432-069X
    Keywords: Rough endoplasmic reticulum ; Oral mucosa ; Morphometry ; Epithelial differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Stereological techniques were applied to investigate several structural parameters characterising the rough endoplasmic reticulum (RER) during differentiation in hamster cheek-pouch epithelium. Mucosal samples from five Syrian golden hamsters were obtained and processed for electron microscopy. Following a strict sampling regime, micrographs were obtained from defined basal, spinous and granular layers, and subjected to stereological point and intersection counting procedures. This enabled volume and surface densities, and volume-to-surface ratios of RER to be determined for each cellular layer. From previous estimaes of the mean cytoplasmic volume of the “average” basal, spinous and granular cell in this tissue, it was possible to calculate the absolute volume and surface area of RER present in these average cells. Both volume and surface densities of RER decreased between basal and granular layers, whereas the total volume and surface area present in the average spinous and granular cell were both higher than in the average basal cell. These data suggest that RER is being synthesised during epithelial differentiation. In view of the role of the RER in the production of exportable proteins, it is possible that increased amounts of this organelle are required to synthesise the enzymes and glycoproteins found in membrane-coating granules, since these are also seen with increasing frequency in successively higher strata.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00404622
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  • 2
    Electronic Resource
    Electronic Resource
    THE ENZYMATIC SYNTHESIS OF N-ACETYLIMIDAZOLE (1953)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 75 (1953), S. 2022-2022 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01104a533
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  • 3
    Electronic Resource
    Electronic Resource
    Total synthesis of (.+-.)-citreoviridin (1987)
    s.l. : American Chemical Society
    The @journal of organic chemistry 52 (1987), S. 5067-5079 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00232a001
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  • 4
    Electronic Resource
    Electronic Resource
    SOME RELATIONSHIPS OF STRUCTURE TO FUNCTION IN RIBONUCLEASE (1959)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 81 (1959), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1959.tb49333.x
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  • 5
    Electronic Resource
    Electronic Resource
    A quantitative ultrastructural study of alterations in the area of the basal cell-stromal interface during experimental oral carcinogenesis (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral pathology & medicine 14 (1985), S. 0 
    Details
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Because of its topographical location, the basal cell in carcinomas must play a significant role in the invasion of adjacent tissues. We have analysed the proportion of the basal cell plasma membrane in direct contact with the adjacent lamina propria during in vivo oral carcinogenesis. Samples of hamster check-pouch mucosa treated with DMBA were assigned to hyperplasia, dysplasia and carcinoma groups using strictly defined histopathological criteria. Electron micrographs of basal cells were subjected to stereological intersection counting to provide estimates of the proportion of the total basal cell membrane in contact with the connective tissue (SSBM,PM). In untreated controls, a mean value of 9% was obtained, whereas, for DMBA-induced hyperplasias, dysplasias and carcinomas, values were 8%, 12% and 16% respectively. Statistically, (SSBM,PM) values were significantly elevated in dysplasias and carcinomas. The changes in this parameter may reflect an increased motility in the transforming basal cell prior to and concomitant with cellular invasion, and may prove to be of value as a structural indicator of malignant transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0714.1985.tb00486.x
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  • 6
    Electronic Resource
    Electronic Resource
    Preliminary assessment of the epithelial nuclear-cytoplasmic ratio and nuclear volume density in human palatal lesions (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral pathology & medicine 24 (1995), S. 0 
    Details
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We have analysed both the nuclear-cytoplasmic (N/C) ratio and nuclear volume densities (VVN) in defined strata from human hard palate lesions with and without malignant potential to determine the prognostic reliability and/or validity of this parameter. Measurements of cellular and nuclear areas of basal and spinous cells from normal (N) and pathological palatal epithelium were made on histological sections using an image analyser. The lesions comprised fibrous hyperplasia (FH), traumatic inflammation (INF), benign hyperkeratosis (HK), squamous cell papilloma (PP), dysplastic epithelium adjacent to invasive carcinoma (CE) and islands of invasive squamous cell carcinoma (CI). In basal cells, no significant differences were detected in comparisons of N/C and VVN between all pathological groups and the N control group. The mean value for CE was lower than that obtained for N. In spinous cells, the only statistically significant comparison was between IF and FH for both N/C and VVN. Both parameters were lower in CE than in N. Of all groups analysed except CI, the CE group is the only one likely to possess an increased malignant potential. The N/C ratio therefore seems to be of no value as a predictor of malignancy in palatal epithelial lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0714.1995.tb01179.x
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  • 7
    Electronic Resource
    Electronic Resource
    Quantitative cellular and nuclear volumetric alterations in epithelium from lichen planus lesions of human buccal mucosa (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral pathology & medicine 23 (1994), S. 0 
    Details
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Patients with oral lichen planus lesions may represent a relatively high risk population for subsequent development of oral cancer. Little is known of the relative effects of chronic inflammation and the process of malignant transformation itself on the histological structure of transforming epithelia. We have assessed cellular and nuclear volumes in defined basal and spinous cells from normal buccal mucosa epithelium, from epithelium associated with a non-specific chronic inflammatory infiltrate and from lichen planus lesions. Normal (N) tissues were obtained from the margins of non-neoplastic buccal mucosa lesions. Inflammatory (INF) lesions were from areas of the buccal mucosa diagnosed clinically as traumatic irritation without ulceration, and lichen planus (LI) lesions were biopsied from areas exhibiting Wickham's striae. Basal and spinous epithelial cells from normal and pathological human buccal mucosa were measured on haematoxylin and eosin-stained sections imaged through a video camera using a ZCELL VIDAS analyser and from these measurements, nuclear (VN) and cellular (VCELL) volumes were determined. VN and VCELL derived for both basal and spinous strata were similar in N and INF groups but were almost doubled in the LI group. Comparisons between LI and all other groups were significantly elevated. The effects of the inflammatory infiltrate on the oral epithelium in lichen planus and in non-specific inflammation thus differ significantly. VN and Vcell may serve as potential discriminators between benign lesions and premalignant lichen planus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0714.1994.tb01114.x
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  • 8
    Electronic Resource
    Electronic Resource
    Alterations in the volume of the intercellular space between epithelial cells of the hamster cheek-pouch: quantitative studies of normal and carcinogen-treated tissues (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral pathology & medicine 13 (1984), S. 0 
    Details
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The present report investigated the extent of the epithelial dysplastic feature known as “loss of cellular adherence” at the ultrastructural level by quantifying the volume of the intercellular space during hamster cheek-pouch carcinogenesis. Following topical application of DMI3A to cheek-pouches, lesions were classified as hyper-plasia, dysplasia and carcinoma, with untreated pouches serving as a control. Stereological point counting procedures were used to determine the volume density of intercellular space in defined basal, spinous and granular layers for each group. In general, progressive increases in volume density were detected within each stratum during carcinogenesis. These results indicate that increasing separation of epithelial cells occurs during carcinogenesis, although it is not yet known whether this results from loss of cohesion between specialised (i.e., desmosomal) or non-specialised membrane areas. In addition, a simple indicator of pathological alteration, the Pathological Alteration Ratio (PAR), is described and was used to evaluate existing published data for intercellular spaces in various oral mucosal conditions. Values of the PAR were found to be substantially higher in carcinogen-treated epithelia than in reports describing changes in wound healing, lichen planus and leukoplakia simplex. These objective techniques are of value for investigating the pathogenesis of diseased epithelium and may find applications in the diagnosis of oral premalignant lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0714.1984.tb01422.x
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  • 9
    Electronic Resource
    Electronic Resource
    A qualitative ultrastructural study of the intercellular spaces between epithelial cells treated in vivo with DMBA (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral pathology & medicine 13 (1984), S. 0 
    Details
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: One of the features of epithelial dysplasia at the histological level is known as “loss of cellular adherence” in which adjacent epithelial cells appear more widely separated from each other than in normal tissues. In this study we examine the effects of the carcinogen DMBA on the epithelium of the hamster cheek-pouch with particular emphasis on the dimensions of the intercellular spaces. DMBA-induced lesions were processed for electron microscopy and assigned to hyperplasia, dysplasia and carcinoma groups, using defined criteria on toluidine blue-stained 1 urn Araldite sections. Untreated pouches were used as a control. At the light-microscopical level, intercellular spaces in hyperplastic epithelium appeared similar to those present in untreated tissue but increased progressively in dysplastic and car-cinomatous lesions. Spaces were generally wider between basal and spinous cells than between granular cells, although wide variations were observed between tissue blocks demonstrating similar histological features and also within adjacent areas of the same block. At the ultrastructural level, untreated and hyperplastic tissue showed only occasional focal separations of adjacent plasma membranes; these spaces were more frequent between cells of lower strata. In sections from dysplasia and carcinomas, spaces were always extensive and were occupied by numerous villous or foliate membrane-bound cytoplasmic extensions. These were often attached to each other by desmosomcs of apparently normal morphology but of a lower frequency than in untreated epithelium. The increased epithelial separation as indicated by the increased intercellular spaces during chemical cardnogenesis may be a result of any or all of the following factors: desmosomal disruption or their failure to develop; the production of cell-surface molecules which are less adhesive; inflammatory oedema and direct alterations on intercellular junctions and cell-surface components by infiltrating inflammatory cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0714.1984.tb01421.x
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  • 10
    Electronic Resource
    Electronic Resource
    Variations in the nuclear-cytoplasmic ratio during epithelial differentiation in experimental oral carcinogenesis (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral pathology & medicine 10 (1981), S. 0 
    Details
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract An increased nuclear-cyloplasmic ratio is one of the cytological features of epithelial alypia taken into account when the histopathologist subjectively assesses whether an epithelial lesion is likely to become malignant. The present work evaluates this ratio ultrastructurally in the DMBA-treated hamster cheek pouch model with a view to assessing whether alterations of this feature represent a valid indicator of malignant transformation. Following DMBA treatment, lesions obtained were assigned to three defined histopathological categories, namely epithelial hyperplasia, epithelial dysplasia and squamous cell carcinoma. Untreated pouches served as controls. Electron micrographs were obtained of basal, spinous and granular layer cells from each of these categories and the N/C ratio was evaluated using stereological point counting techniques. The results indicated that progressive decreases in the ratio occurred in all pathological stages during differentiation (i.e., between basal and granular cells). During carcinogenesis there was a tendency for the ratios to decrease in each cell layer but significant differences were not detected between normal and premalignant lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0714.1981.tb01262.x
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