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  • 1980-1984  (7)
  • 1975-1979  (6)
  • Cell & Developmental Biology  (13)
  • Electromyography
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 103-119 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Classical light microscopic studies on pigmentation of Fundulus heteroclitus (killifish) indicated that there are three groups of light reflecting cells; one group on the surface of scales reflects white light, while two other deeper groups (the melaniridophores and the stratum argenteum) are iridescent. The results presented here show that: (1) The scale leucophores reflect white light by a Tyndall light-scattering mechanism, by virtue of the presence of randomly oriented organelles of “novel” morphology. (2) The iridophores of the melaniridophores contain stacks of irregularly-spaced, large reflecting platelets which function as an imperfect multiple thin layer interference system. (3) The stratum argenteum consists of a continuous layer(s) of iridophores with reflecting platelets which are so regularly packed as to approach an ideal multiple thin layer interference system. (4) In all three types of light reflecting cells, the dimensions and packing (orientation) of the reflecting organelles satisfactorily account for the chromogenic properties of the cells, including colors as viewed under transmitted, reflected, or polarized light. (5) The spacial relationships between these light reflecting cells and adjoining melanophores are different for each type of light reflecting cell. Furthermore, we propose to replace the term reflecting platelet with refractosome.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 155 (1978), S. 181-192 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: New data on the brain of Latimeria indicate that previous estimates of the brain weight were too high by a factor of two. Our data suggest a brain weight of 1.1-1.5 grams for a specimen with a body weight of 30 kilograms. Quantitative data on major divisions of the brain are presented for the first time, and the relative size of the major brain divisions is similar to that of sturgeons and generalized sharks (such as hexanchids and squalids). Examination of brain component weight (s): body weight plots in a sample of non-teleost actinopterygian fishes indicates that all major divisions of the brain, except the telencephalon, are larger than in Latimeria. Brain component sizes in Latimeria are more similar to those extrapolated for amphibian brains than to those for actinopterygians. However, the cerebellum of Latimeria is considerably larger than that of amphibians.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 27-32 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Three pairs of specialized axons found in other muscoid flies are absent in the tsetse, Glossina morsitans, which also lacks the tergotrochanteral muscle. Neither light nor electron microscopy could demonstrate any evidence for the cervical giant fiber axon, the peripherally synapsing axon, or the tergotrochanteral motor axon. The specialized characteristics of these axons must have been altered during the evolution of Glossina. This divergence of individual neurons from the more typical muscoid pattern not only demonstrates the evolutionary modification of specific identified cells; it may also provide an opportunity to study the ontogenetic determination of unique neuronal features.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 170 (1981), S. 321-345 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fiber type composition distinguished by the level of succinic dehydrogenase, mean fiber diameter, and fiber number were determined for the gracilis major and sartorius in ontogenetic series of the anurans Rana pipiens, Bufo americanus, and Xenopus laevis to characterize muscle composition and mode of muscle growth.A correlation can be made between the respective locomotor mode of these anurans, their activity physiology, and the fiber type composition of the propulsive muscles. R. pipiens and X. laevis have hindlimb muscles composed primarily of fast-twitch, fast-fatiguing type 1 fibers. B. americanus's muscles are composed of slow-twitch, slow-fatiguing type 2 and type 3 fibers. Fiber typing is apparently useful in explaining interspecific anuran locomotor capability previously difficult to correlate with body shape. Fiber typing also affords an explantion for reported variations in metabolism during strenuous activity.Postmetamorphically, anuran muscles grow by a combination of hyperplasia and hypertrophy, but the percent fiber type composition remains unchanged. In R. pipiens and X. laevis, the muscles grow primarily by hypertrophy with the addition of relatively fewer fibers. The converse is true for B. americanus. In all three species the combinations result in strong positive allometric increases in muscle cross section. Anuran muscle growth is similar to that reported for fish and different from that associated with mammals.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Microridges (MR), also called microvillar ridges, microplicae and cytoplasmic folds, have been noted on many epithelial surfaces. Several functions have been proposed for these structures. In the present study we examine the mechanical role that microridges may play in holding mucus to the lumenal surface of the esophagus in the trout Salmo gairdneri. Our findings support the hypothesis that the microridges help hold a protective coat of mucus to the epithelium. In addition, the complex curved or whorled arrangement of microridges appears to facilitate the spread of mucus away from goblet cells.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 145 (1975), S. 189-207 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The spermatozoon of Cucumaria pseudocurata is unique among those of the echinoderms in that it is tabloid in shape, i.e., elongated and dorsoventrally compressed. The sperm consists of a dorsal surface which contains an extensive striated rootlet-like structure located within a dorsal groove and a ventral surface which contains a medially situated acrosome. A single mitochondrion lies at the base of the nucleus. The flagellum is unusual in that a 9 + 3 tubular arrangement is observed in the mid-tail region.The acrosome consists of an acrosomal granule bounded by a limiting membrane and a surrounding periacrosomal layer. The granule is irregular in shape with the anterior-posterior surfaces flaring out, forming pockets in the periacrosomal material. The ventral granule surface bulges forming a close association with the plasma membrane. The dorsal surface is indented. Ventral to the depression (within the granule) is a small area containing a particulate-fibrous material. To the inside of the granule limiting membrane there is a second membrane-like structure (incomplete) which extends from the anterior-posterior surfaces around the dorsal face of the granule. Dorso-medial to the granule the periacrosomal layer contains a particulate-fibrous region lodged within the granule depression. This material is presumably the precursor of the acrosomal filament.Prominent cytoplasmic folds extend off from the basal flagellar region. The proximal and distal centrioles are situated perpendicular to one another within the mitochondrion. Centriolar satellite materials are associated with both centrioles. Toward the base of the tail the satellite of the distal centriole consists of nine radiating arms extending at an angle of 45° to the axis of the centriole. Each arm terminates in a dense thickening. The striated rootlet extends anteriorly from the distal centriole to just below the level of the acrosome.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In rat pancreatic islets, the glucagon-producing A-cells also contain a GIP-like material as revealed by the peroxidaseantiperoxidase immunocytochemical technique. Control studies showed that this dual staining was not due to the cross-reactivity of anti-GIP with glucagon. It is concluded either that the A-cells synthesize a GIP-like peptide or that it is taken up from the circulation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Development of pia-arachnoidal membranes in the mouse occurs in four stages: the first (prenatal days 10-13) follows closure of the neural tube and is a period of initial vascularization of the developing telencephalon; the second (prenatal days 14-16) is a period of delineation during which the limits of the subarachnoid space are defined; the third (prenatal day 17 to birth) is a period of ensheathment of pia-arachnoidal blood vessels, and the fourth (birth to postnatal day 21) includes addition of smooth muscle to larger vessels, the appearance of macrophages in the subarachnoid space, and a general increase in extracellular collagenous and elastic fibers.The mesenchyme over the telencephalic surface in the 10-day fetus has a typically large extracellular space. By the 13th fetal day cerebrospinal fluid begins to seep into and replace it. The mesenchymal extracellular compartment is reduced peripherally, resulting in a compacted pia-arachnoidal tissue which limits the peripheral extent of the subarachnoid space. By the 21st postnatal day a subarachnoid space typical of the adult animal has been established.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 160 (1981), S. 231-246 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The microanatomy of the yellow corpuscles (adrenocortical homologue, AH) in the holostean fish, Lepisosteus spp., was studied by serial sectioning, steroid histochemistry, and electron microscopy. The modification of this tissue to short-term ACTH treatment was also observed. The distribution of the AH within the renal tissue of the garpike phylogenetically represents a more advanced condition than that seen in its closest holostean relative, the bowfin, and appears to approximate that in teleosts. The homology of this tissue to vertebrate adrenocortical tissue was established by the positive identification of the enzyme, Δ5-3β-hydroxysteroid dehydrogenase, and by the ultrastructural features of the cells before and after ACTH administration.The AH cells possess fine structural features characteristic of steroidogenic cells, namely, polymorphic mitochondria with tubular cristae, abundant tubules of smooth endoplasmic reticulum, a prominent Golgi complex, and lipid droplets. Other interesting features include the presence of annulate lamellae and a variety of dense bodies. Digitonin perfusion results in the deposition of presumed, cholesterol-digitonide crystalline spicules on the surface microplicae of the cells and as dense accumulations in association with smooth endoplasmic reticulum. ACTH administration results in swelling of mitochondria, a loss of their cristae, and a decrease in electron density of their matrices. Alterations also occur in the smooth and rough endoplasmic reticulum, and large osmiophilic inclusions of irregular profile appear. Some of the ACTH-induced modifications are similar to those observed in the adrenocortical cells of other vertebrate groups following comparable stimulation.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 4 (1981), S. 83-95 
    ISSN: 0148-7280
    Keywords: human spermatozoa ; flagellum ; motion ; microcinematography ; kinematics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A microcinematographic (50 f/s) study was performed on motile human spermatozoa. Eighty percent were found to have a linear trajectory and a pseudo-sinusoidal head displacement pattern. Throughout their progression, the spermatozoa periodically rotated on their longitudinal axis at a frequency equal to that of flagellar wave formation. These waves were found always to begin on the same side of the cell and to propagate in the flattened plane of the head until the moment of rotation. At this time the wave had reached a point near the middle of the flagellum. Beyond this point, the flagellum moves out of the plane of the head. Different variables used to characterize the movement of spermatozoa included the velocity of progression, amplitude and velocity of head displacement, frequency of rotation, wave amplitude, and propagation velocity of the flagellar wave. Among these variables, it was the propagation velocity of the wave that was found to be best correlated with the velocity of spermatozoan progression. This flagellar wave exhibited two stages, one of initiation and one of propagation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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