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  • 1
    Electronic Resource
    Electronic Resource
    Alterations in the epithelial surface of A/Jax mouse palatal shelves prior to and during palatal fusion: A scanning electron microscopic studySupported in part by NIH grant DE-02987 to L. M. Ross, and NIH grants DE-01766-10, DE-00278-02 and Ford Foundation grant 710-0036. (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 176 (1973), S. 361-375 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The surfaces of palatal shelves from carefully staged A/Jax mouse embryos were examined with the scanning electron microscope prior to and during palatal fusion. No change was observed in the appearance of cells covering the oral and nasal surfaces of the shelves. A change was observed, however, in the region of presumptive fusion, and was detectable on vertical shelves just prior to transposition. This change initially involved surface cells along the future medial edge of the shelf at the level of the second to third rugae. It was characterized by a loss of distinct cellular boundaries, the appearance of intercellular gaps caused by apparent retraction of adjacent cells, and a progressive accumulation of filamentous material at the surface. These alterations spread posteriorly along the medial edge of the shelf during transposition and fusion. While it was impossible to determine the precise nature of the surface change from S.E.M. data alone, the fact that it both preceded closure and was restricted to the region of subsequent contact and fusion between the shelves suggests it may be a prerequisite for normal palatal fusion and may represent an expression of the acquisition of a potential to fuse similar to that proposed for palatal fusion in vitro.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091760311
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  • 2
    Electronic Resource
    Electronic Resource
    SEM observations of surface alterations associated with neural tube closure in the mouse and hamster (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 183 (1975), S. 95-98 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091830109
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  • 3
    Electronic Resource
    Electronic Resource
    Epithelial fusion during early semicircular canal formation in the embryonic zebrafish, Brachydanio rerio (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 210 (1984), S. 101-114 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The developing inner ear of the teleost, Brachydanio rerio, provides an opportunity for observing an epithelial fusion between the apical surfaces of apposed epithelia in a vertebrate embryo in vivo. The developing otocyst was filmed for periods up to 4 days in unanesthetized embryos, and specimens were fixed at intervals and processed for light microscopy, TEM and SEM. The semicircular canals are formed as a consequence of the union between the tips of three cylindrical projections from the wall of the otocyst, which grow toward corresponding bulges of a projection from the lateral wall. The epithelial cells covering the projections contain extensive rough endopasmic reticulum, exhibit apical junctional complexes, and are not underlain by a basal lamina. The core of each projection contains large amounts of flocculent and fibrillar extracellular material. After a period of growth and elongation, the tip of each projection contacts, and adheres to, the appropriate bulge to create a circular, flattened, bilayered, epithelial plate. Small, focal junctions form between the apposed apical cell surfaces within the plate during this period, but they are not numerous. Junctional complexes do develop, however, between apposed cells at the periphery of the plate. After 1-2 hours, the basal surfaces of the plate exhibit considerable alteration in contour. Adjacent cells within the plate then separate to allow continuity of the connective tissue components of the two structures. The observations of this study indicate that following an initial period of contact and adhesion, cellular reorientation and changes in junctional contacts between adjacent cells within the epithelial plate, rather than cell degeneration, are responsible for perforation of the plate.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092100113
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  • 4
    Electronic Resource
    Electronic Resource
    Fine structure of scale development in the teleost, Brachydanio rerio (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 168 (1970), S. 361-379 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Mature and embryonic scales of the zebrafish, Brachydanio rerio, were examined by light and electron microscopy. Each scale consists of a mineralized “osseous layer” superficially and a deeper, non-mineralized, “fibrillary plate.” The mineralizing matrix contains randomly oriented filaments in decalcified sections, whereas the fibrillary plate is composed of orthogonally arranged lamellae of banded collagen fibrils embedded in electron dense material.Scale papillae and small scales first appear in the midbody region of fry between 0.95 and 1.14 cm long. The matrix of the osseous layer is produced prior to the fibrils of the fibrillary plate. Foci of mineral deposition appear in this matrix soon after its production, and increase gradually in number and extent. Cells surrounding the periphery of the scale are continuous with two layers of cells beneath the inner surface and with two layers extending a variable distance over the superficial surface. These “scale-associated” cells are separated from the dermal collagen by other investing cell processes. The probable roles of these cells in scale formation are discussed and the need for further investigation of the fish scale as a mineralizing system is stressed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091680304
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  • 5
    Electronic Resource
    Electronic Resource
    Alterations in the epithelial surface of human palatal shelves prior to and during fusion: A scanning electron microscopic study (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 180 (1974), S. 111-135 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The surface topography of palatal shelves was examined by scanning electron microscopy prior to and during secondary palate formation in 72 therapeutically aborted human embryos and fetuses ranging in age from 37 days to 12 weeks (post-fertilization). Alterations in epithelial surface appearance were observed in the prospective region of fusion prior to contact between the shelves. First seen as an elliptical area along the anterior portion of the presumptive medial edge, a zone of alteration spread progressively along the anterior four-fifths of the medial edge prior to shelf contact, and continued along the posterior one-fifth of the shelf as fusion proceeded. The altered zone eventually extended onto the oral surface in the middle of the shelf but was restricted to a narrow zone along the medial edge posteriorly. Initially characterized by elongation and “intertwining” of superficial cells, alterations later included cell death, desquamation and possible active migration of surface cells. The shelf epithelium subjacent to the zone of alteration exhibited increased irregularity in thickness and numerous “invaginations” into the underlying mesenchyme. These alterations are thought to reflect intrinsic changes within the shelf and may play a role in the fusion process. Evidence for surface remodeling following fusion was also observed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091800111
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  • 6
    Electronic Resource
    Electronic Resource
    In vitro activation of adenylate cyclase by parathyroid hormone and calcitonin during normal and hydrocortisoneinduced cleft palate development in the golden hamster (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 188 (1977), S. 431-443 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An adenylate cyclase highly responsive to stimulation by parathyroid hormone (PTH) and calcitonin (CT) in vitro was observed at certain times during normal prenatal development of the maxillary-palatal process complex in the golden hamster. Responses of the enzyme to these hormones were barely detectible at the earliest stage examined (day 10/20). The enzyme became extremely sensitive to activation by either hormone during the time of rapid growth of the palatal processes (day 11/20) and during fusion between the palatal processes (day 12/20). Thereafter, responses were greatly diminished and little or no activation of adenylate cyclase was observed until birth. Adenylate cyclase from fetuses in which clefts of the secondary palate were induced by maternal treatment with hydrocortisone (50 mg) on day 11/3 also displayed an enhanced sensitivity to PTH and CT on day 11/20, but the sensitivity of the enzyme was greatly decreased from that in normal animals during the normal time of palatal fusion (day 12/20) and was barely detectible or absent at the remaining time periods studied (days 13/20 and 14/20). Addition of hydrocortisone to the incubation mixture, either separately or in combination with PTH or CT, did not remarkably affect the response of adenylate cyclase to these hormones. Moreover, the appearance of the adenylate cyclase sensitive to hormonal activation did not result from changes in phosphodiesterase activity during palatal maturation.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091880404
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  • 7
    Electronic Resource
    Electronic Resource
    Development of the lateral musculature in the teleost, Brachydanio rerio: A fine structural studyPart of a study submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Biological Structure, University of Washington, Seattle, Washington. (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 125 (1969), S. 457-493 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The lateral musculature in the midbody region of the teleost, Brachydanio rerio, was examined by light and electron microscopy in the adult and six developmental stages. Two main divisions of the adult lateral musculature are described: (1) a superficial portion composed of small, dark fibers with high fat content and succinic dehydrogenase (SDH) activity; and (2) a deep portion composed principally of larger, pale, “deep fibers” showing little SDH activity and containing little fat. Some “intermediate fibers” are also present in the deep portion near the horizontal septum. Myofibrils of all cell types appear ultrastructurally similar.A general outline of myotomal differentiation has been established for the midbody somites. Myogenesis begins at the medial surface of the somite between the 20- and 25-somite stages and progresses laterally. Shortly before hatching, the myotome contains two structurally dissimilar types of young muscle cells. The appearance of these two muscle cell populations in larvae and fry supports the hypothesis that they develop into the superficial and deep portions of the adult lateral musculature. The intermediate fiber population is present by 2 1/2 months. The most lateral cells of the somite form a layer of flattened cells covering the lateral myotomal surface in the 33-somite embryo, and are considered to form the dermatome in this species.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001250406
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  • 8
    Electronic Resource
    Electronic Resource
    Topographical changes along the neural fold associated with neurulation in the hamster and mouse (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 146 (1976), S. 151-171 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The topography of the ectoderm was examined by scanning electron microscopy during neurulation in hamster and mouse embryos. Stages from the appearance of the neural folds to closure of the posterior neuropore were studied. Progressive development of a zone of altered cellular morphology was observed along the crests of the neural folds. This zone evolved from and abrupt transition between surface and neural regions of the ectoderm to a narrow band of flattened cells which exhibited numerous membranous “ruffles” in the mouse, or blebs and presumably degenerating cells in the hamster, immediately prior to contact between the folds. These alterations were more prominent along the anterior than the posterior portions of the folds. Contact of the folds occurred first between the flattened cells with subsequent union of the surface cells. Stages of neural crest cell formation were observed subjacent to the zone of alterations in histological sections. It is suggested that the observed surface alterations may reflect changes in the membrane properties of the altered cells which are correlated with both neural crest formation and initial adhesion between the folds.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001460204
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