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  • 1
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The secretory end-pieces of the submandibular gland of rats during the first week of postnatal development are studied with regard to the fine structure of the secretion granules in these end-pieces. The terminal ends of the secretory ducts during this period consist of two types of cells; one cell is an acinar-type and the other is a duct-type found in the gland of adult rats. The secretion granules of the acinar-type cells are similar in appearance to those of the acinar cells in the gland of adult rats, and the structure of these granules remains the same throughout the week. However, granules widely different in appearance are present in the duct-type cells, and their structure varies in different cells as well as within a single cell at different stages of development. These granules contain unusual substructures which are not found in the secretion granules of adult rats, suggesting that the granules are transitory. Granules containing short tubular profiles are predominant in the gland of one day-old rats. A large number of granules in three day-old rats contain elongated tubules. More granules of widely different substructures are present in the gland of seven day-old rats than in the gland of younger rats. The matrix of the granules in seven day-old rats is of higher density than that of the granules in younger rats. In the dense matrix of these granules, less dense tubules form fingerprint-like or somewhat more irregular patterns.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 144 (1975), S. 467-475 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Adenyl cyclase activity in mucous acinar cells and serous demilune cells of the rat sublingual gland was localized cytochemically. After incubation with adenylyl-imidodiphosphate (AMP-PNP) as substrate, deposits of reaction product are found along the cell membranes bordering the secretory surfaces of serous demilune cells. These are the membranes which participate directly in secretion by fusing with the granule membranes. The granule membranes of the demilune cells do not reveal reaction product, but the membranes of the granules which are fused with and become part of the cell membrane do show deposits. Thus, it appears that the cell membranes which fuse with granule membranes during secretion are associated with a high level of adenyl cyclase activity. In support of this, the luminal membranes of the mucous acinar cells which do not fuse with granule membranes during secretion are not associated with detectable amounts of adenyl cyclase activity.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 248-256 
    ISSN: 1059-910X
    Keywords: Esophageal reflux ; Morphometry ; Distinctive cell ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In Barrett's esophagus, metaplastic columnar epithelium replaces the normal squamous epithelium. The importance of this lesion lies in the increased incidence of adenocarcinoma of the esophagus occuring in patients with Barrett's esophagus. We characterized the surface epithelial cells of Barrett's esophagus using quantitative scanning electron microscopy. Three distinct surface cell types, in addition to the goblet cell, were recognized in Barrett's epithelium: the gastric-like cell and the intestinal-like cell, both of which were similar to normal gastric and small intestinal surface cells, respectively, by quantitative scanning electron microscopy, and the variant cell which had a range of surface features. In four biopsy specimens from the squamo-Barrett's junction in three patients, we found the distinctive cell that had features intermediate between those of squamous and columnar epithelium. On the distinctive cell's surface there are two disparate structures not normally present on the same cell in the gastrointestinal tract: microvilli (a scanning electron microscopy feature of glandular epithelium) and intercellular ridges (a scanning electron microscopy feature of squamous epithelium). The surface characteristics of this cell were almost identical to those of cells found in the transformation zone of the uterine cervix, an area in which squamous epithelium physiologically replaces columnar epithelium. Scanning electron microscopy of Barrett's esophagus has increased our understanding of this precancerous lesion by showing striking cellular heterogeneity. It has also identified the distinctive cell which may represent an intermediate step in the development of Barrett's epithelium during which the surface characteristics of two different cell types, columnar and squamous, coexist in the same cell. © 1995 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 99 (1979), S. 239-246 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A variant of murine L5178Y lymphoma resistant to procaine hydrochloride (PH) was selected by exposing the cells to gradual increments of PH in the growth medium until the cell grew exponentially in the presence of 1.5 mM PH. Using cinephotomicrography, it was observed that the majority of cells that initially succumbed to PH failed to undergo successful mitosis. With respect to chromosomal, cell size distribution and flow microfluorometric analyses, the PH-resistant cells are very similar to a spontaneous tetraploid cell line (R1T) previously cloned. The isolated cells, designated R1/P, were also found to be cross-resistant to analogues of PH, namely, lidocaine, tetracaine and dibucaine. The naturally-occurring tetraploid cell line (R1T) was also found to be more resistant to local anesthetics, although not to the same extent as R1/P cells. Since the enzyme that hydrolyzes procaine appears to be absent in all these lymphoid cell lines, the difference in resistance does not appear to depend on differences in the ability of these cells to remove the agent. It is suggested that an alteration in the structure and/or function of the plasma membrane in R1/P cells have rendered them either less sensitive to the membrane-perturbing effects of the local anesthetics or less permeable to local anesthetics molecules. The ability of local anesthetics to affect membranes and cytoskeleton structures may play a role in the genesis and/or selection of these cell variants.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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