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  • 1
    Electronic Resource
    Electronic Resource
    Iodination (125I) of the apical plasma membrane of toad bladder epithelium: Electron-microscopic autoradiography and physiological effects (1973)
    Springer
    The journal of membrane biology 14 (1973), S. 17-32 
    Details
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The apical plasma membrane of toad bladder epithelial cells has been enzymatically iodinated, using lactoperoxidase, H2O2 (generated by a glucose-glucose oxidase system) and NaI. The site of labeling was demonstrated by electron-microscopic autoradiography; the silver grains (125I) were found exclusively overlying the luminal plasma membranes of the epithelium. The iodination reaction reached completion in less than 5 min. The dependence of the degree of iodination on NaI concentrations (range=6.3×10−8 to 6.3×10−2 m) in the mucosal medium was determined. The results suggest that three classes of sites are iodinated within this concentration range. At concentrations of NaI of 6.3×10−6 m or less, iodination of the apical membrane had no significant effect on either the fine structure of the epithelium or on electrophysiological properties. The baseline short-circuit current (SCC) remained steady and the response to vasopressin was unimpaired. At concentrations of 6.3×10−5 m NaI and greater, the baseline SCC was depressed and the response to vasopressin was partially inhibited. The results indicate that125I may serve as a covalent marker (specific for tyrosine and histidine residues) of the apical plasma membrane of epithelia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01868066
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  • 2
    Electronic Resource
    Electronic Resource
    The membrane surfaces of the toad bladder: Scanning and transmission electron-microscopy (1974)
    Springer
    The journal of membrane biology 16 (1974), S. 279-295 
    Details
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The SEM permits analysis of large areas of the surface of epithelia and facilitates the study of cell-to-cell relationships, as pointed out by Fenguson and Heap (Z. Zellforsch.109:297, 1970). The short method of preparation described here yields good results when the critical point method is used for drying (freeze-drying was less satisfactory). Cell counts reveal that theBufo marinus toad bladder epithelium contains 3 or 4 granular (GR) cells to 1 mitochondria-rich (MR) cell. Whether these cell membrane contacts are permeable to the diffusion of high energy compounds and whether the MR cells serve as a source of energy for the GR cells are hypotheses that require further study. In view of the wide variations in the cell number per unit area even in single hemibladders, experimental measurements should probably be expressed either in terms of cell counts of DNA content, rather than per unit surface area.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01872419
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  • 3
    Electronic Resource
    Electronic Resource
    Differential covalent labeling of apical and basal-lateral membranes of the epithelium of the toad bladder (1976)
    Springer
    The journal of membrane biology 26 (1976), S. 301-317 
    Details
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The apical (luminal) plasma membrane of toad bladder epithelial cells has been labeled with (125I) diazo-diiodo sulfanilic acid (125I-DDISA) as demonstrated by electron-microscopic autoradiography. The silver grains (125I) were localized exclusively to the apical surface. At concentrations of DDISA of 10−3 m or less, binding to the apical membrane had no significant effect on the fine structure of the epithelium. At concentrations of DDISA of 10−6 m or less, the baseline short-circuit current (SCC), and the response to cyclic 3′,5′-adenosine monophosphate (cAMP) plus theophylline were unimpaired. At 10−5 m, baseline SCC was unchanged and the response to cyclic AMP plus theophylline was enhanced. At concentrations of 10−4 m and greater baseline SCC was depressed and the response to the nucleotide inhibited. The basal-lateral epithelial plasma membranes were labeled by exposing the serosal side to pyridoxal phosphate and reducing the resultant Schiff base with sodium borotritide (3H-NaBH4). In electron-microscopic autoradiographs, the silver grains (3H) were found over the basal and lateral surfaces of the epithelium. At concentrations of pyridoxal phosphate of 10−4 m and3H-NaBH4 of 10−3 m, there were no significant changes in the fine structure of the epithelium. Addition of pyridoxal phosphate (10−4 m) and NaBH4 (10−3 m) to the serosal side decreased the baseline SCC significantly but not the response to vasopressin. Covalent attachment of the125I and the3H was indicated by resistance to elution in the preparation of the sections for electron-microscopy and the reagent requirements for binding.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01868879
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  • 4
    Electronic Resource
    Electronic Resource
    Lectin histochemistry of developing submandibular glands of fetal Syrian golden hamsters (1991)
    Springer
    Anatomy and embryology 183 (1991), S. 135-141 
    Details
    ISSN: 1432-0568
    Keywords: Submandibular gland ; Fetal development ; Lectin ; Hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Lectin binding was studied in the developing submandibular glands of fetal Syrian golden hamsters (Mesocricetus auratus) from gestational day 12 to 16 (the day of birth). The fetuses were fixed, embedded in paraffin, sectioned and stained with nine lectin-horseradish peroxidase conjugates: concanavalin A (Con A), wheat germ agglutinin (WGA), Dolichos biflorus agglutinin (DBA), Helix pomatia agglutinin (HPA), Maclura pomifera agglutinin (MPA), Griffonia simplicifolia agglutinin I-B4 (GSA I-B4), peanut agglutinin (PNA), Ulex europens agglutinin I (UEA I) and Limulus polyphemus agglutinin (LPA). The developing glands showed dramatic morphological alterations on a daily basis, accompanied by progressive changes in lectin staining. On day 12 the primitive gland showed only trace lectin staining with WGA, HPA, MPA, PNA and UEA I, but by day 13, strong staining with these lectins, as well as with DBA, was seen at the ductal lumenal surface, after the formation of the ductal lumens. Secretory granules first appeared in cells of the primitive acini on day 14; the secretion products were stained strongly with WGA, DBA, HPA, MPA, PNA and UEA I. On day 15, the secretion products were also stained moderately with GSA I-B4. Secretory differentiation was further developed on day 16, but the staining intensity of the mucins with the different lectins varied among the secretory cells. LPA failed to stain any part of the gland throughout the observation period, and Con A stained only glycogen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174394
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  • 5
    Electronic Resource
    Electronic Resource
    Estrogen-induced alterations in the myoepithelial cells of the rat mammary gland (1978)
    Springer
    Cell & tissue research 193 (1978), S. 155-161 
    Details
    ISSN: 1432-0878
    Keywords: Mammary gland ; Myoepithelial cell ; Estrogen ; Myofilaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Estradiol benzoate was injected into virgin rats, at a concentration of 50 μg/day, for 7 days. The animals were fixed by perfusion and the mammary glands prepared for electron microscopy. Many myoepithelial cells in the mammary glands were altered as a result of the estradiol treatment. The affected cells had a markedly reduced number of myofilaments that were restricted to a specific region of the cytoplasm. Large foot-like projections with many vesicles extended from the myoepithelial cells into the surrounding connective tissue. The altered cells also had more organelles, suggesting that their metabolic activity was increased. Nuclei in the altered cells had deep infoldings that may reflect an increase in nuclear/cytoplasmic exchanges. The results of this study indicate that estradiol causes specific morphological alterations in myoepithelial cells of the mammary gland.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221608
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  • 6
    Electronic Resource
    Electronic Resource
    Comparative analysis of surface charges on luminal epithelial membranes of urinary bladders from toad, frog, turtle, and tortoiseWith the financial aid of U.S.P.H.S., National Institute of Arthritis, Metabolism, and Digestive Diseases, Grant AM 13659, and National Heart and Lung Institute, Grant HL 06285. (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 180 (1974), S. 509-519 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Cationized ferritin was used to analyze the surface charges on the luminal epithelial cell membranes of urinary bladders from toad (Bufo marinus), bullfrog (Rana catesbiana), turtle (Pseudemys scripta and Clemmys caspica), and tortoise (Geochelone carbonaria and Testudo graeca). The labeling, done at a physiological pH on fixed or unfixed bladders, revealed differences in the distribution and density of negative charges along the luminal membrane surfaces. The epithelial surface of toad bladder did not label with cationized ferritin. Frog bladder labeled lightly and the labeling pattern varied between cell types. The epithelial membrane surfaces of reptile bladders were heavily labeled, in contrast to amphibian bladders. Luminal surfaces from fresh water turtles were not as heavily labeled as those from land tortoises. The degree of labeling varied from cell type to cell type in all reptile bladders except Pseudemys scripta. An analysis of the degree and pattern of labeling by cationized ferritin in bladders of all species studied might reflect a difference in the nature of the glycocalyx of a particular membrane, the presence or absence of negative surface charges or their availability (i.e., interference by mucus), and/or the nature of the chemical groups comprising the surface structure of the membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091800310
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  • 7
    Electronic Resource
    Electronic Resource
    Fine structure of the urinary bladder of the bullfrog, (Rana catesbiana)With the financial aid of U.S.P.H.S., National Heart and Lung Institute, grant HL 06285 and NIAMD grant AM 13659. (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 178 (1974), S. 15-39 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The urinary bladder of the bullfrog, Rana catesbiana has been studied by light and electron microscopy. Three epithelial cell types were found: (1) granular cells, (2) mitochondria-rich cells, and (3) basal cells. The structure of the Rana catesbiana bladder differs from that of the toad Bufo marinus, in several respects: it lacks a mucous (goblet) cell type, its granular cells do not contact the underlying basement membrane, it has specialized, smooth-muscle cell-basal epithelial cell contacts, not previously described in amphibian bladders, and its mucosa is richly innervated. Mitochondria-rich cells within the bullfrog bladder epithelium were occasionally observed touching the basement membrane. The specialized smooth muscle-basal cell contacts provide anatomical evidence for how regulatory vasoactive substances such as neurohypophyseal peptides might alter epithelial geometry. Many nerve endings invest the mucosa just beneath the epithelial basement membrane in proximity to mitochondriarich cells and basal cells. The possible role of neural regulation in epithelial transport was discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091780104
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  • 8
    Electronic Resource
    Electronic Resource
    Site of lodination in rat mammary gland (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 235-244 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The ability of the mammary gland to take up and organically bind radioiodide was studied in non-pregnant, pregnant, and lactating rats. Autoradiography was used to determine whether duct cells or alveolar cells are responsible for iodination in the rat mammary gland. Iodination was not detected in mammary glands from non-pregnant rats, but occurred late in the twelfth day of gestation and continued throughout pregnancy and lactation. Protein-containing vacuoles in alveolar cells and casein-like proteins in milk were the major sites where iodination occurred within the gland. Milk proteins in the lumens of ductules adjacent to alveoli were also iodinated. In contrast, ducts, myoepithelial cells, fat cells, blood vessels and other histological components of the gland did not show iodinating capability. Cytochemistry was also used to identify endogenous mammary peroxidase activity in the same glands, and it was found that the presence and location of this enzyme was correlated with the ability to iodinate.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091920204
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  • 9
    Electronic Resource
    Electronic Resource
    Autoradiographic evidence of a loss of iodination within hormone-dependent GR mouse mammary tumors as they progress to independence (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 204 (1982), S. 323-332 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The purpose of this study was to determine by use of light- and electron-microscope autoradiography whether or not iodination occurred in mammary tumors of female GR mice. Of the sixty tumors studied it was found that pregnancy-dependent and hormone-induced tumors possessed iodinating ability. Although mammary glands from nonpregnant GR mice lacked the ability to iodinate, by the 16th day of pregnancy in response to hormonal stimulation the glands readily iodinated casein, and some epithelial cells contained ultrastructural cytochemical evidence of mammary peroxidase. Preneoplastic mammary gland lesions known as hyperplastic alveolar nodules were also able to iodinate, as were plaques, the disc-shaped lesions which give rise to the hormone-responsive mammary tumors in this strain. Plaques also contained epithelial cells with mammary peroxidase activity. When hormone-induced mammary tumors were transplanted into syngeneic mice they retained the ability to iodinate for several generations. However, as the tumors progressed to hormone independence, the ability to iodinate was gradually lost. Hormone-independent mammary tumors from GR mice lacked both iodinating ability and cytochemical evidence of mammary peroxidase. These findings suggest that iodination depends upon hormone-responsive cells within the mammary tumors and that as these cells become hormone unresponsive, the ability to iodinate is lost.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092040405
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  • 10
    Electronic Resource
    Electronic Resource
    Immunochemical localization of Clara cell protein by light and electron microscopy in conducting airways of fetal and neonatal hamster lung (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 227 (1990), S. 77-86 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An antibody to a protein produced by Clara cells in adult Syrian golden hamsters has been used to monitor the development and functional differentiation of secretory cells in the conducting airway epithelium of this species. Lungs from fetal and neonatal hamsters at gestational day 11 and at intervals up to and including 3.5 weeks of age (as well as adults) were studied. The earliest time this Clara cell protein could be identified by immunoperoxidase labeling in the fetal conducting airways was at gestational day 15. On this day, labeling was observed in a few secretory cells lining the trachea, in many lining the lobar bronchi, and in virtually all secretory cells lining the bronchioles. Ciliated cells and endocrine cells were not labeled. Granules first appeared within the apical cytoplasm of the secretory cells on gestational day 15 at all airway levels. To identify the exact subcellular location of this protein, an ultrastructural labeling procedure using protein A gold was employed. The gold particles labeled only electron-dense granules within the secretory cells, indicating that they represent the specific site of this protein. Since secretory cells in the most distal conducting airways began to produce this protein on the same day in development as cells in the larger airways, including the trachea, this expression of functional maturation occurs simultaneously throughout the conducting respiratory tree rather than proceeding sequentially in a cranial to caudal direction. Consequently, secretory cells lining the smaller conducting airways mature more rapidly than those lining the larger airways.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092270109
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