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  • 1975-1979  (608)
  • 1920-1924
  • 1890-1899
  • 1976  (608)
  • Cell & Developmental Biology  (502)
  • Ultrastructure  (106)
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  • 1975-1979  (608)
  • 1920-1924
  • 1890-1899
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  • 1
    ISSN: 1432-2307
    Keywords: Ultrastructure ; Thyroid ; Mucosal neuromas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron-microscopic and histochemical studies of thyroid tumor, tongue neuromas and eyelid neuromas from the lesions of a patient with medullary thyroid carcinoma were compared. In the thyroid tumor, a significant number of the C cells showed heterogeneity of granule types; no C cells, however, were identified in the tongue and eyelid neuromas. Amyloid was clearly shown by Congo red staining in the thyroid neoplasm and in the tongue neuromas. In all tissues, amyloid fibrils were found to be ultrastructurally closely associated with fibroblasts. These fingings suggest that the fibroblast rather than the C cell may have played the important role in the deposition of amyloid in this patient's thyroid carcinoma.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neurology 213 (1976), S. 295-303 
    ISSN: 1432-1459
    Keywords: Neuronal ceroid lipofuscinosis ; Lipopigments ; Ultrastructure ; π-granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei einem Patienten mit spätinfantiler und 3 mit juveniler NCL wurden periphere Nerven verschiedener Herkunft (Armplexus, N. suralis und 2 Hirnnerven) elektronenmikroskopisch untersucht. Im Lichtmikroskop wurden keine signifikanten histologischen Veränderungen gefunden. Kurvilineäre und/oder Fingerabdruck-Einschlüsse konnten ultrastrukturell in jedem Fall festgestellt werden, und zwar hauptsächlich in Schwannschen Zellen. Außerdem fanden sich lamelläre π-granulaähnliche Cytosomen. Sie kamen in den juvenilen Fällen gewöhnlich gar nicht und in dem spätinfantilen Fall lediglich vereinzelt mit kurvilineären/Fingerabdruck-Profilen gemeinsam vor. Bei spärlichen Veränderungen an Axonen und Myelinscheiden könnten diese Cytosomen Zeichen einer chronischen Schädigung der Schwannschen zellen sein und die spezifische morphologische Ausprägung eines „cellulären Verschleißprozesses“ darstellen, wie er im Alter und bei der NCL diskutiert wird. Biopsien aus peripheren Nerven eignen sich aufgrund der zahlreichen π-Granula und ihrer Varianten weniger zur Diagnose der NCL als beispielsweise solche der Haut, der Skeletmuskulatur und des Rectums.
    Notes: Summary Specimens of brachial plexus, sural nerve and two cranial nerves of one patient with the Jansky-Bielschowsky type and 3 patients with the Spielmeyer-Sjögren type of NCL were studied by electron microscopy. Significant light microscopic changes were absent in all specimens. Ultrastructurally, curvilinear and/or fingerprint inclusions were present in each case, located chiefly in Schwann cells. These diagnostic findings were, however, overshadowed by masses of lamellar π-granule-like cytosomes, usually not mixed with curvilinear or finger-print profiles in the juvenile cases and only rarely associated with curvilinear profiles in the late infantile case. Since secondary changes of axons and myelin sheaths were mild, these lamellar cytosomes might indicate chronic damage to Schwann cells, perhaps by “wear and tear” as seen in aging as well as NCL. On account of the abundance of π-granules in NCL, peripheral nerve biopsy appears less suitable for confirming this diagnosis than biopsy of skin, striated muscle and rectal tissue.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Planta 133 (1976), S. 15-19 
    ISSN: 1432-2048
    Keywords: Tropaeolum, Embryogenesis ; Differentiation ; Plastids ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Embryogeny in the nasturtium is characterized by the development of a large, tripartite suspensor and storing cotyledons. A light and electron microscopic study revealed an early diversification of the plastids in the various regions of the suspensor and the embryo proper. Amyloplasts are found in the developing cotyledons of the heart-like embryo, while chloroplasts occur within the meristematic part of the embryo and the adjacent portion of the suspensor. The cells between the meristem and the storing cotyledons display undifferentiated leukoplasts, whereas leukoplasts with an electron-dense matrix occur in the basal cell mass of the embryo-suspensor. Etioplasts develop in several cells of the placental haustorium of the suspensor. The carpel haustorium shows rather undifferentiated leukoplasts, which are transformed into electron-dense plastids during autolysis of the suspensor. This early plastidal differentiation in discussed with respect to its control and functional significance.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 371 (1976), S. 121-129 
    ISSN: 1432-2307
    Keywords: Compound cilia ; Axial filament complex ; Bronchitis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Atypical cilia in the bronchial mucosa of non-smoking women and in guinea-pig lungs were studied by the electron microscope. In human cases, numerous compound cilia were observed in the main bronchi. The largest one contained about 40 axial filament complexes in a ciliary shaft. Occasionally, atypical basal bodies were also seen. In the experimental model in guinea-pigs, 50% oxygen at one atmospheric pressure damaged the bronchial surface and resulted in degeneration and reduction of cilia and pellicular structures. The injury was not sufficiently severe to initiate adaptation and reparative mechanisms in the bronchial mucosa, and rapid renewal of the surface structures was found. The human cases were associated with bronchogenic carcinoma but the experimental model suggested that atypical cilia were not always related to pulmonary carcinogenesis.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 371 (1976), S. 161-170 
    ISSN: 1432-2307
    Keywords: Giant cell granuloma ; Histochemistry ; Ultrastructure ; Cell function ; Osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die mehrkernigen Riesenzellen des zentralen Riesenzellgranuloms entstehen durch Zellfusion aus den Pericyten der Kapillaren. In der vorliegenden Studie werden die Funktionsmerkmale der Riesenzellen durch Kombination histologischer, histochemischer und elektronenmikroskopischer Methoden untersucht. In den mehrkernigen Riesenzellen ließen sich in Übereinstimmung mit älteren Untersuchungen die lysosomalen Enzyme saure Phosphatase und Aminopeptidase nachweisen. Das lysosomale System der Riesenzellen befähigt diese zur aktiven Phagocytoseleistung. Darüber hinaus können sich die Riesenzellen neugebildeten Geflechtknochenbälkchen anlagern und osteoclastäre Funktionen übernehmen. Die enzymhistochemische und funktioneile Ähnlichkeit mit den mehrkernigen Osteoclasten wirft die Frage nach einer vergleichbaren Cytogenese beider Zellformen auf.
    Notes: Summary Multinucleated giant cells in giant cell granuloma are formed by cell fusion of capillary pericytes. In our present study we tried to analyze cell function and activity by histologic, histochemical, and electronmicroscopic examination of giant cells. Lysosomal enzymes such as acid phosphatase and amino-peptidase were found in giant cells which is in agreement with former work. By their lysosomal system giant cells are proved phagocytic. In addition, giant cells being localized at trabecular surfaces of newly formed woven bone may develop osteoclastic functions. The enzymatic and functional resemblance of giant cells and multinucleated osteoclasts points to the possibility of a similar cytogenesis of both cell types.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 371 (1976), S. 219-226 
    ISSN: 1432-2307
    Keywords: Canine mammary gland ; Mixed tumor ; Myoepithelial cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurden licht- und elektronenmikroskopisch Spindelzellen fischzugartiger Verbände in 19 Mammamisehtumoren von Hündinnen untersucht. Die elektronenmikroskopischen Befunde sprechen dafür, daß es sich bei den spindeligen Tumorzellen meist um Zellen myothelialen Ursprungs handelt. Es wurden jedoch auch spindelzellige Verbände gefunden, die aus Fibroblasten bzw. Pibrocyten bestehen. Im lichtmikroskopischen Bereich ist eine sichere Unterscheidung nicht in jedem Fall möglich.
    Notes: Summary Spindle cells of myomatous formations of 19 canine mixed mammary tumors were studied by light and electron microscopy. The EM findings indicate that the spindleshaped tumor cells are mostly of myoepithelial origin. However there were also formations of spindle cells which consisted of fibroblasts or fibrocytes. By light microscopy they are not always clearly distinguishable.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 370 (1976), S. 163-175 
    ISSN: 1432-2307
    Keywords: Central giant cell granuloma ; Histogenesis ; Histochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bisherige Untersuchungen an zentralen Riesenzellgranulomen des Gesichts-Kieferbereiches haben die Histogenese dieser tumorähnlichen Knochenerkrankung nicht klären können. Wir untersuchten daher zwei bioptisch gesicherte zentrale Riesenzellgranulome unter dieser Fragestellung histochemisch und elektronenmikroskopisch. Histochemisch findet sich eine enge Enzymverwandtschaft zwischen den mehrkernigen Riesenzellen und den Pericyten der Kapillaren, die das Granulom dicht durchsetzen. Elektronenmikroskopisch zeigen sich typische Membranphänomene der Zellfusion zwischen den mehrkernigen Riesenzellen und den Pericyten. Die für das Granulom charakteristischen mehrkernigen Riesenzellen entstehen daher durch Zellfusion aus den Pericyten, die als ihre Stammzellen angesehen werden müssen. Da die Pericyten das Granulom auch in Form zahlreicher blinder Kapillarsprossen durchsetzen, erklärt sich die Entwicklung einer Vielzahl von Riesenzellen. Die Ursachen, die diesem Verhalten der Pericyten aetiologisch zugrunde liegen, sind unbekannt. Ob die Cytogenese der Riesenzellen des zentralen Riesenzellgranuloms Modellcharakter hat und analog auch für die Entwicklung von Riesenzellen in anderen Gewebsneubildungen oder für die Enstehung der mehrkernigen Osteoclasten gilt, muß weiteren Untersuchungen vorbehalten bleiben.
    Notes: Summary Until now numerous studies on central giant cell granuloma of jawbones have not been able to reveal the histogenesis of this tumourlike lesion. The aim of the present investigation in two surgically proven cases was to study this question by means of histochemical and electron-microscopic methods. Rather similar histochemieal properties were shown in giant cells and pericytes of capillary sprouts penetrating the granuloma. Cell fusion occurred between both cell types as was observed by electron microscopy. The process of cell fusion is defined by characteristic interdigitations of cell membranes. Therefore pericytes are believed to be the stem cells of multinucleated giant cells in giant cell granuloma. The abundance of giant cells usually occurring in the granuloma might be explained by plenty of capillary sprouts made up by clusters of pericytes. The factors inducing the pericytic cell fusion process are still unknown. The question arises whether cytogenesis of giant cells in giant cell granuloma might be similar in other giant cell lesions or even in the development of multinucleated osteoclasts.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 372 (1976), S. 205-226 
    ISSN: 1432-2307
    Keywords: Breast ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of the terminal ductal-lobular unit (TDLU) of the normal, resting female breast is described. Tissue used conformed to strict criteria for normal. 4 distinct cell types, were observed, epithelium, myoepithelium, macrophages and lymphocytes. A gradation in structure, especially of myoepithelium, was found between the ductule tip and intralobular duct, apparently reflecting the age and function of each region. Cilia originating from the myoepithelial cells are possibly sensory in function. Epithelial vesicular inclusions may represent minimal secretory activity, transport of material across the cell, or be lysosomal in nature. The capillaries in close contact with the delimiting fibroblasts of the epithelial-stromal junction (ESJ) are described and the zone designated the capillary-fibroblast junction (CFJ). The CFJ is conceived as a regulatory unit similar to the ESJ, and may contribute to dysplasia due to biochemical or functional alterations, or to disruption of the microvascular geometry.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 369 (1976), S. 215-227 
    ISSN: 1432-2307
    Keywords: Kaposi's sarcoma ; Endothelial cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Das wesentliche histologische Substrat des M.K. ist charakterisiert durch eine Proliferation von Zügen spindelförmiger Zellen, durch zellig begrenzte Gefäßspalten und durch eine geringfügige zellulär-entzündliche Begleitreaktion. 2. Die Zellen, welche die Gefäßspalten begrenzen, vehalten sich wie Capillarendothelzellen. Sie zeigen eine starke alkalische Phosphatase-Reaktivität und eine deutliche Leucinaminopeptidase-Aktivität; sie enthalten typische Weibel-Palade Granula. 3. Die ultrastrukturelle Analyse der Tumorzellen läßt ferner gefäßsprossenartige Formationen mit und ohne Lumen erkennen, an deren Ausbildung in der Hauptsache wenig ausdifferenzierte Endothelzellen beteiligt sind. Daneben erscheinen fibroblastoide Tumorzellen die sich möglicherweise von den Perithelzellen herleiten lassen. 4. Typisch für M.K. sind Extravasation und Phagocytose von Erythrocyten mit intracytoplasmatischem Abbau und Einlagerung myelinartiger, an Schwannzellen erinnernde Figuren. 5. Folgerung: Der M.K. ist gekennzeichnet durch eine multifokale Neubildung kapillarartiger Strukturen mit einer progressiven sarkomatösen Entwicklung.
    Notes: Summary 1. Histologically, Morbus Kaposi is primarily characterized by a proliferation of streams composed of spindle-shaped cells, by vascular slits lined by cells, and by a minor cellular inflammatory reaction. 2. The cells lining the vascular slits resemble endothelial cells and exhibit strong alkaline phosphatase activity and a clear leucinaminopeptidase activity. They contain Weibel-Palade bodies. 3. The ultrastructural analysis of the tumor cells shows a proliferative formation resembling capillary sprouts with and without lumina. The lumina are composed primarily of poorly differentiated endothelial cells. A second typical cellular component are fibroblast-like tumor cells possibly derived from perithelial cells. 4. Indicative of M.K. are also extravasation and phagocytosis of erythrocytes with intracytoplasmic decomposition, and storage of myelinlike structures somewhat resembling Schwannian-cells. 5. Conclusion: M.K. is characterized by a multifocal neoplasia of capillary like structures and by a progressive sarcomatous development.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 371 (1976), S. 199-217 
    ISSN: 1432-2307
    Keywords: Giant cell tumor of soft parts ; Histopathology ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The light-microscopic and ultrastructural findings in a case of so-called giant cell tumor of soft parts, localized at the dorsal side of the left foot of a 23-years-old male are described. An amputation of the lower extremity was performed and subsequently chemotherapy with adriamycin was given for 3 months. Despite the histology and cytologic malignant appearance and the evident vascular invasion, already present at the time of the first excision, the last known status 2 years later seems favorable. There are no pathologic lymph nodes in the groins and no signs of metastases on chest X-rays. From the electron-microscopic study no definite conclusion can be drawn as regards the histogenesis of this tumor. We feel, as do others, that many of the principal mononuclear tumor cells are poorly differentiated mesenchymal cells. Some of the neoplastic cells, however, show ultrastructural features suggestive of chondro- or osteoblasts (a well-developed r.e.r. containing electron-dense material; multiple Golgi complexes; masses of glycogen; interdigitating cell membrane villi; cytoplasmic filaments; an extracellular amorphous matrix). Some of the larger tumor cells have the submicroscopic aspects of histiocytes as described in osseous, cutaneous, or pulmonary lesions of the histiocytosis X group. As yet undetermined cytoplasmic inclusion bodies constitute another rare observation in our material.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 86 (1976), S. 55-68 
    ISSN: 1432-1335
    Keywords: Rhabdomyosarcoma ; Rhabdomyoblast ; Cellular Differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In der vorliegenden Untersuchung werden die cytomorphologischen Merkmale eines embryonalen Rhabdomyosarkoms des Nasenrachenraumes bei einem 10 jährigen Jungen aufgezeigt. Aufgrund der Ultrastruktur lassen sich im Tumor 4 Zelltypen darstellen: 1. Undifferenzierte mesenchymale Tumorzellen mit großem, euchromatischem Zellkern und schmalem, organellenarmem Cytoplasma; 2. undifferenzierte Tumorzellen mit einem Netzwerk von Intermediärfilamenten (Durchmesser etwa 100 Å) im breiten Cytoplasma; 3. unreife Rhabdomyoblasten mit zunehmender Entwicklung spezifische Myofilamente (Myosin: 180–210 Å, Actin: 68–80 Å Durchmesser); 4. reife Rhabdomyoblasten mit Myofibrillen in sarkomerischer Gliederung (Sarkomerlänge: 1,8 μ). Die starken Glykogenablagerungen in einigen cytoplasmareichen Tumorzellen werden als Zeichen eines Degenerationsprozesses gedeutet. Die cellulären Entwicklungsstadien des embryonalen Rhabdomyosarkoms sind identisch mit dem Ablauf der Embryogenese sowie der Regeneration normaler quergestreifter Muskulatur. Daher bieten sich für die Entstehung des embryonalen Rhabdomyosarkoms zwei Denkmodelle an: 1. Entstehung des Tumors aus einer undifferenzierten mesenchymalen Tumorstammzelle und 2. Atypische Regeneration nach Schädigung der quergestreiften Muskulatur mit Übergang in ein autonomes Tumorwachstum. Die zweite Hypothese ist jedoch wenig wahrscheinlich, da bis heute weder morphologisch noch experimentell eine derartige Tumorentstehung nachgewiesen werden konnte und zudem ätiologisch gesicherte Faktoren zur Induktion von Rhabdomyosarkomen beim Menschen fehlen.
    Notes: Summary An embryonal rhabdomyosarcoma of the nasopharynx of a 10 year old boy is analysed with light and electron microscopy. With regard to cell shape and cytoplasmic features the following four tumour cell types could be distinguished: 1. Undifferentiated mesenchymal cells with a big loosely packed nucleus and a small cytoplasmic rim with only few cell organelles; 2. Undifferentiated tumour cells with a broad cytoplasmic body which contains a dense network of nonspecific intermediate filaments with a diameter of about 100 Å; 3. Immature rhabdomyoblasts with randomly orientated specific myofilaments; 4. Fully differentiated rhabdomyoblasts with well developed myofibrils often showing a sarcomeric pattern. Glycogen deposits which were seen in great masses in many tumour cells were regarded to result from degenerative processes within the tumour. The cellular stages in the development of rhabdomyoblasts are basically identical to those known from the embryogenesis and regeneration of striated muscle. From these observations the two following developmental pathways are suggested: 1. Origin of the tumour from an undifferentiated mesenchymal cell; 2. Atypical regeneration of striated muscle which terminates in malignant progressive tumour growth. At present, the body of information about rhabdomyosarcomas supports the assumption of an origin from immature mesenchymal cells. Nevertheless, the second theory cannot be totally excluded.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 149 (1976), S. 155-171 
    ISSN: 1432-0568
    Keywords: Large intestinal epithelium ; Postnatal development ; Rat ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The principal cells of the surface of the cecum, the ascending colon, and the descending colon in postnatal developing rats were investigated using both light and electron microscopy. In rats 1 to 14 days old the ultrastructure of the surface principal cells in the cecum and ascending colon were characterized by apical tubulo-vacuolar systems and large supranuclear vacuoles similar to those in the absorbing cells of the neo-natal ileum as reported by Clark, 1959, and others. After about the 16th day, the special membrane system disappears from the principal cells of the proximal large intestine. On the other hand, in the descending colon, this special membrane system was absent from the cytoplasmic matrix of the epithelium. It is thought that the proximal portion of the large intestine together with the distal part of the small intestine actively participate in the absorption of protein molecules at least during the early postnatal period.
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  • 13
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    Springer
    Anatomy and embryology 149 (1976), S. 323-346 
    ISSN: 1432-0568
    Keywords: Oculomotor nucleus ; Ultrastructure ; Synapses ; Membrane apposition ; Motoneurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure, of the somatic efferent portion of the nucleus of the oculomotor nerve was studied in four adult cats. The neuronal population is composed of neurons of variable size. A continuous pattern of morphological aspects is evident between the large neurons, which show abundant cytoplasm with well developed organelles and the small neurons which have a reduced amount of cytoplasm. The dendrites are generally smooth, with few short spines. Axo-somatic and axo-dendritic synapses are numerous. Synaptic boutons are also present on the axon hillock. The neuropil is characterized by the occurrence of small groups of dendrites which may be in direct touch with their membranes. Direct membrane appositions may also occur between neighbouring neurons and between the cell somata and tangentially running dendrites. Generally beneath the site of apposition there is accumulation of mitochondria, multivesicular bodies, coated vesicles and moderately dense amorphous material. The morphological features suggest the possibility of cellular interchanges at the sites of direct membrane apposition. Five types of synaptic boutons were recognized on the basis of their vesicular content, the presence of abundant filaments in the pre-synaptic bag, the occurrence of post-synaptic specializations. The, different synaptic types and their distribution are similar to those reported in the spinal motor nuclei. Many of the synapses make synaptic contacts with two or more post-synaptic elements. Axo-axonic synapses were also observed.
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  • 14
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    Acta neuropathologica 34 (1976), S. 353-357 
    ISSN: 1432-0533
    Keywords: Normal pressure hydrocephalus ; Human cerebral cortex ; Ultrastructure ; Extracellular space
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A cortical biopsy was taken at the time when ventricular pressure was measured, or a ventriculo-atrial shunt placed, in 11 patients with Normal Pressure Hyprocephalus (N.P.H.), and was studied with the electron microscope. In 9 cases, a rather typical electron microscopic picture with marked increase of extracellular space in an otherwise normal cortical neuropil was observed. 2 patients did not exhibit this pattern and, coincendentally, did not benefit from the placing of the shunt. As a control, about 600 cortical biopsies that had been taken for other reasons were reviewed. In the group, there were only 3 cortices that had a pattern of increased extracellular space similar to the described in N.P.H. On review of the clinico-pathologic data of these cases, it was felt that all 3 probably represented cases of normal pressure hydrocephalus. It is concluded that the ultrastructure of the cerebral cortex is of at least nosological interest in the study of N.P.H.
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  • 15
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    Archives of microbiology 107 (1976), S. 321-327 
    ISSN: 1432-072X
    Keywords: Claviceps purpurea ; Saprophytic ; Clavine alkaloids ; Ultrastructure ; Extended hyphae ; Blastospores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ultrathin sectioning of submerged mycelium of Claviceps purpurea Tul. producing clavine alkaloids revealed yeast-like budding resulting in asexual sporesblastospores. These deciduous spores were born by extended hyphal cells and retained the same ultrastructure of cell organelles. Both the extended hyphae and the blastospores resembled the cells of ergot sclerotial tissue. A surface culture of C. purpurea Tul. producing no alkaloids was used as a reference.
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  • 16
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    Archives of toxicology 35 (1976), S. 115-125 
    ISSN: 1432-0738
    Keywords: Cerium ; Microsomal enzyme inducers ; Pregnenolone-16α-car-bonitrile ; Estradiol ; Fatty liver ; Ultrastructure ; Triglycerides ; Cerium ; Arzneimittelmetabolisierende Enzyme ; Pregneno-lon-16α-carbonitril „PCN“ ; Oestradiol ; Leberverfettung ; Elektronenmi-kroskopie ; Triglyceride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Nach Vorbehandlung mit Steroiden und mit nicht steroidartigen Substanzen (Pregnenolon-16α-carbonitril „PCN“, Dexamethason, Spironolacton, Phenobarbital), welche die arzneimittelmetabolisierenden Enzyme der Leber stimulieren, und nach Oestradiol, wurde die Sterblichkeit und die Lebertoxicität der weiblichen Ratte erheblich verändert. PCN, Oestradiol, Dexamethason senken die hepatischen Triglyceride wesentlich, jedoch erhöht Dexamethason die Sensitivität der Tiere für CeCl3 bedeutend. Spironolacton und Phenobarbital üben keine große Wirkung auf die Triglyceride aus. Licht- und Elektronenmikroskopie zeigten, daß die durch CeCl3 hervorgerufenen hepatocellulären Veränderungen durch PCN, Oestradiol und Dexamethason bedeutend verringert wurden. Die Steroide dürften die Verteilung und die Bindung des Metalles an das endoplasmatische Reticulum verändern, und somit diese Membranen vor Cerium schützen.
    Notes: Abstract In female rats, the lethality and hepatotoxicity of cerous chloride (CeCl3) were significantly altered by pretreatment with steroidal and nonsteroidal compounds (pregnenolone-16α-carbonitrile “PCN”, dexamethasone, spironolactone, phenobarbital) that stimulate hepatic drug-metabolizing enzyme activity and by estradiol. PCN, estradiol, and dexamethasone considerably decreased hepatic triglycerides, but the latter steroid also greatly sensitized the animals to CeCl3 lethality. Spironolactone and phenobarbital similarly lowered the triglyceride level but not significantly. Light and electron microscopy indicated that the hepatocytic damage elicited by CeCl3 was decreased significantly by PCN, estradiol, and dexamethasone. The steroids may have altered the distribution and binding of the metal to the endoplasmic reticulum (ER) thus protecting these membranes against the effect of cerium.
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  • 17
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    Archives of microbiology 108 (1976), S. 167-174 
    ISSN: 1432-072X
    Keywords: Red algae ; Gracilaria verrucosa ; Tumor-like formations ; Ultrastructure ; Viruses ; Endoplasmic reticulum ; Plastids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper deals with electron microscopic observations on cultivated plants of the marine red alga Gracilaria verrucosa which developed simple galls; also sea collected material, without galls, had been studied. The galls showed unusual but characteristic cell structures, caterpillar-like bodies, containing rows of fusiform bodies. These were found mostly in the cytoplasm near the plastids, in one case connected with the endoplasmic reticulum, occasionally even inside the nucleus, and are described here, as far as we know, for the first time. It does not seem probable that the caterpillar-like bodies represent mitochondria or bacteria, but the hypothesis that fusiform bodies are related to virus-like structures is discussed. The normal tissues as well as the gall tissue of the laboratory plants contained, besides plastids typical for the red algae, another type of plastids characterized by tubular thylakoids.
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  • 18
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    Archives of microbiology 108 (1976), S. 305-312 
    ISSN: 1432-072X
    Keywords: Nitrobacter agilis ; Chemoorganotrophic growth ; Acetate ; Formate ; Pyruvate ; Yeast extract-peptone ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. After a resting period of up to 6 months cells of Nitrobacter agilis grow with acetate, formate, and pyruvate as carbon and energy source. Yeast extract and peptone were added to supply the organism with nitrogen and to meet possible vitamin requirements. 2. The length of the growth period depends on the substrate; it increases according to the following sequence: pyruvate, formate, acetate. The highest growth yield is observed with pyruvate, the lowest with formate. 3. O2 consumption is increased in the presence of substrates as compared to endogenous respiration. With pyruvate and acetate twice as much O2 is consumed, with formate 7 times, with yeast extractpeptone 10 times as much. 4. The ability of nitrite oxidation is largely preserved, except in cells grown with acetate or pyruvate in the presence of 0.015% yeast extract and peptone. Such cells have nearly no cytochrome a 1. Accordingly, the cytochrome spectra of nitrite oxidizers grown under chemoorganotrophic and lithoautotrophic conditions coincide qualitatively. 5. The nitrite oxidizing system is inducible. It is induced by nitrite but also by substances present in yeast extract and peptone. Cells grown on acetate and yeast extract and peptone (0.015%) require 3–4 weeks before they regain the ability to grow with nitrite. Cells grown chemoorganotrophically with the same substrates and yeast extract and peptone (0.15%) start growing with nitrite as energy source without a lag. 6. Cell size and form, distribution of storage materials, order and fine structure of double membranes are correlated with growth conditions.
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  • 19
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    Archives of microbiology 107 (1976), S. 277-282 
    ISSN: 1432-072X
    Keywords: Nitrosococcus mobilis ; Ammonia oxidizing bacterium ; Morphology ; Ultrastructure ; Physiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An ammonia-oxidizing bacterium was isolated from a sample of brackish water (North Sea, Harbour of Husum). It is a motile large coccus 1.5–1.7 μm in diameter. The extensive cytomembrane system occurring as flattened vesicles in the peripheral region of the cytoplasm and as intrusions into the center of the cytoplasm is to be emphasized as a characteristic mark of identification. The lithoauto-trophically growing bacterium turned out to be an obligate halophile. Because of its physiological and morphological properties, we assigned it to the genus Nitrosoccus and propose the name Nitrosococcus mobilis.
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  • 20
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    Archives of microbiology 109 (1976), S. 277-288 
    ISSN: 1432-072X
    Keywords: Ultrastructure ; Mucorales ; Piptocephalis ; Mycoparasitism ; Cokeromyces ; Yeastphase ; Appressorium ; Infection peg ; Penetration ; Haustorium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Infection of the mucoraceous host Cokeromyces recurvatus by Piptocephalis unispora was studied ultrastructurally, using a new technique involving yeast-phase cells of the host to obtain large numbers of infection sites for thin-sectioning. Morphologically, the haustorial apparatus was similar to that of fungi parasitic on higher plants, and comprised an appressorium, a neck region with a collar and a neck ring, and a lobed region surrounded by a sheath matrix enclosed in an extra-haustorial membrane. Penetration of the host by the infection peg probably involved both enzymatic degradation and physical pressure. Reaction of the host to infection is described and the results related to the theory of host infection by haustorial fungal parasites.
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  • 21
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    Archives of microbiology 108 (1976), S. 105-111 
    ISSN: 1432-072X
    Keywords: Ammonia oxidizing bacterium ; Nitrosovibrio tenuis ; Isolation ; Morphology ; Ultrastructure ; Physiology ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An ammonia-oxidizing, autotroph growing, slender, curved rod was isolated from the soil of Hawaii. It is well distinguishable from any other nitrifying bacteria thus far described by their morphology. The cells are 1.1–3.0 μm long and 0.3–0.4 μm wide. They are motile by means of 1–4 subpolar to lateral flagella. In contrast to most of the ammonia-oxidizing bacteria the isolated vibrio is void of an extensive cytomembrane system. To categorize this not yet described species we propose to create the new genus Nitrosovibrio and to classify the isolated strain as Nitrosovibrio tenuis.
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  • 22
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    Acta neuropathologica 36 (1976), S. 393-396 
    ISSN: 1432-0533
    Keywords: Ceroid lipofuscinosis ; Juvenile or adult ; Protracted form ; Lipopigments ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Clinical and ultrastructural findings consisting of curvilinear and fingerprint residual bodies, in a protracted juvenile form of NCL are reported from a woman who died at the age of 35 years. Homochrony and homotypy of her brother's illness emphasize intrafamilial similarities within subgroups of lysosomal disorders.
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  • 23
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    Acta neuropathologica 34 (1976), S. 237-253 
    ISSN: 1432-0533
    Keywords: Strabismus ; Extraocular muscles ; Hirano bodies ; Ultrastructure ; Luse bodies ; Leptomeres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Thirty extraocular muscles (EOM) from 20 patients were evaluated by light microscopy (LM), electron microscopy (EM), and enzyme histochemistry (EZH). Twenty-one EOM were obtained from 13 patients with strabismus, 9 EOM from 4 patients undergoing eye surgery for other reasons and from 3 autopsy cases. One μm thick sections revealed marked variation in muscle fibre shape and size and in myofibrillar structure; also noted were small, hypertrophied, whorled, and ringbinden fibres. Dense and granular material in the central portion of some fibres and sarcomere disruption in 2–3 μm sections was observed. EZH revealed the absence of the classical mosaic pattern usually found in skeletal muscles. ATPase studies were inconsistent and did not correlate with the expected reciprocal activity of NAD-H diaphorase, particularly on the large fibres. Ultrastructural features consisted of vacuoles within myofilament bundles, “smearing” of Z bands, and “nemaline rods”. Occasional myelin figures and lipid-like droplets were observed in subsarcolemmal spaces, associated with scattered clusters of glycogen granules. Abnormal mitochondria and subsarcolemmal inclusions of dense and granular material were conspicuous. “Leptomeric” profiles, “Zebra bodies”, or “striated bodies” were noted in 8 EOM's, and an Hirano body was found in 1. The intramuscular nerves contained structures resembling “Luse bodies” in 7 cases. These observations suggest that EOM from individuals with and without strabismus possess unique structural characteristics suggestive of developmental and morphological disarrangement of contractile elements. Some of these changes might play a role in the pathogenesis of strabismus and in the development of clinical symptoms. These features are significantly different from striated skeletal muscle. Therefore the criteria used in the pathological evaluation and diagnosis of skeletal muscle disorders cannot be unequivocally applied to EOM investigations. These data establish the necessity to determine histological norms, ultrastructural patterns, and develop new enzyme histochemistry criteria for the evaluation of EOM. Only then can an acceptable comparison of EOM and skeletal muscle be made.
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  • 24
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    Acta neuropathologica 35 (1976), S. 159-181 
    ISSN: 1432-0533
    Keywords: Leprosy neuropathy ; Ultrastructure ; Angiopathy ; Basement membrane ; “Blood-nerve barrier”
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Radial or superficial peroneal nerve biopsies of 6 patients with tuberculoid or borderline-tuberculoid leprosy and 6 control nerve biopsies were examined by electron microscopy. Endoneurial blood vessels showed histopathology in all the leprosy patients. Changes, in particular, involved the basement membrane in postcapillary venules and venules. Multilayered parellel basement membranes, with collagen and ground substance, formed a thick coat (“hyaline zone”) around the vessels. It is suggested that the zone inhibits passage of nutrients and metabolites and, thus, contributes to or is the main cause of the local destruction of (unmyelinated) nerve fibres and the lack of nerve fibre regeneration observed in this type of leprosy. The perivascular zone, presumably, is produced by pericytes in response to defects in the “blood-nerve barrier” of endoneurial vessels. In granulomata of leprosy skin lesions, a perivascular zone was not present. The endothelium of endoneurial vessels, in affected nerves, generallywas normal. Occasionally, however, gaps and fenestrations were seen and there were histological indications that leakage of blood plasma had occurred through the gaps and through the basement membrane of the endothelium. Occlusion of endoneurial vessels was found only in the oldest patient and the degeneration of nerve fibres generally observed thus is considered not to be caused by ischaemia. Histopathology in epi-and perineurial vessels was definitely less pronounced than in endoneurial vessels.
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  • 25
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    Acta neuropathologica 36 (1976), S. 85-90 
    ISSN: 1432-0533
    Keywords: Mitochondrial inclusions ; Mitochondria ; Peripheral ganglia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuronal perikarya of peripheral ganglia contained unusual dense core mitochondria that were not seen in other cell types or tissues of the same individual. They were found in several patients autopsied with GM1-gangliosidosis and neuronal ceroid-lipofuscinosis. Previous observations on human sympathetic ganglia, obtained by biopsy, and our findings suggest that these dense core mitochondria might represent a rare but regular feature of neuronal perikarya in peripheral ganglia of man.
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  • 26
    ISSN: 1432-1106
    Keywords: Rat ; Hypoglossal nucleus ; Inhibited regeneration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron micrographs of the left hypoglossal nucleus were quantitatively analyzed in adult rats 52 to 98 days after transection of the left hypoglossal nerve and implantation of the proximal stump into the already innervated ipsilateral sternomastoid muscle, a procedure which prevented the transected nerve from regenerating. Many presynaptic boutons with clear spherical synaptic vesicles and symmetrical synapses were lost from the injured perikarya and dendrites. Some perikarya and dendrites (and, rarely, boutons) became electron dense, and astrocyte or microglial sheaths partly surrounded them. Numbers of dendrite profiles in the neuropil decreased. These statistically significant effects persisted throughout the postoperative period, whereas after axotomy with unimpeded nerve regeneration, these features would have returned to normal by 84 days postoperatively. It was therefore suggested that their recovery depended upon successful regeneration and reconnection of the hypoglossal nerve with the tongue. Subsurface cisterns, and profiles containing unusual inclusions, were numerically normal 52 to 98 days postoperatively, so it was suggested that their early response and recovery after simple axotomy might be entirely dependent on nerve disconnection and not on nerve reconnection.
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  • 27
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    Mycopathologia 59 (1976), S. 117-123 
    ISSN: 1573-0832
    Keywords: Ultrastructure ; Zygospore ; Mycorrhizal fungus ; Flaming crown
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The ultrastructural organization of the spores of the sporocarp of Endogone flammicorona was studied. Two types of organization are described. Initially the spore possessed a vacuolate protoplasm and was bound by two cell wall layers. The spore was surrounded by a hyphal mantle formed of a sheet of vacuolized hyphae with uniformly thin walls. Secondly, although the ultrastructural features of the spore appeared the same, it was now surrounded by a hyphal mantle with unevenly thickened walls (i. e., the so-called flaming crown) due to the gradual and irregular deposition of granules and lamellae. This crown gives the spore its most commonly observed morphological feature and is the preminent character employed taxonomically to speciate Endogone flammicorona Trappe & Gerdemann.
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  • 28
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    Cell & tissue research 168 (1976), S. 489-505 
    ISSN: 1432-0878
    Keywords: Fundus striati ; Cat ; Nine bouton types ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An attempt has been made to discriminate additional types of synapses than have been previously described in the nucleus accumbens septi of the cat, which can, according to Brockhaus (1942), justifiably be termed the fundus striati due to the fact that it possesses all of the morphological and some of the neurochemical features of the striatum. This was undertaken in order to correlate at least one type of synapse with each different afferent pathway. Nine distinct types of synapses could be differentiated electron microscopically: Type I: axo-spinous synapses with sparse, small, round vesicles which seemed to be the nigro-striatal endings (35%). Type II: axo-somatic or axo-dendritic en passant synapses containing small, round vesicles (3%). Type III: axo-spinous synapses filled with densely-packed, small, round vesicles displaying strong postsynaptic thickenings which seem to be corticostriatal (17%). Type IV: large axo-spinous synapses with densely-arranged, small, round vesicles contacting larger spines branching off a pedicle (9%). Type V: axo-somatic or axo-dendritic synapses containing large pleomorphic vesicles, probably axon collaterals (1%). Type VI: axo-somatic or axo-dendritic synapses with elongated small vesicles (20×45 nm) (3%). Type VII: large axo-somatic or axo-dendritic synapses filled by denselypacked, small, round vesicles (11%). Type VIII: large axo-somatic or axo-dendritic synapses containing loosely-arranged, small, round vesicles (8%). Type IX: axo-somatic or axo-dendritic synapses containing large, round vesicles in a translucent axoplasm (13%).
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  • 29
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    Cell & tissue research 168 (1976), S. 549-559 
    ISSN: 1432-0878
    Keywords: Hypothalamic-hypophysial-adrenal axis ; Rat ; Development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The adrenal glands of decapitated and encephalectomized fetal rats were investigated electron microscopically and compared to those of normal intact fetal rats. Although the adrenal cortices did not show three zones (zona glomerulosa, fasciculata, and reticularis) on the 16.5th day of gestation when the decapitation or encephalectomy was carried out in utero, the zonation was recognized in fetuses operated on the 21.5th day of gestation. The same was true for normal control fetuses. However, cytoplasmic characteristics suggesting steroidogenesis in the cortical cells were reduced to various degrees in the encephalectomized or decapitated fetuses, especially in the latter ones. The change in cytoplasmic appearance was more conspicuous in the inner portion of the cortex. This result suggests that for the maintenance of normal adrenocortical function the hypothalamus may be indispensable even during the prenatal life of rats.
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  • 30
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    Cell & tissue research 173 (1976), S. 401-406 
    ISSN: 1432-0878
    Keywords: Pars intermedia ; Ultrastructure ; Peroxidase ; Stellate cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To study the penetration of protein from the blood into and through the pars intermedia of anurans, the electron-dense tracer, horseradish peroxidase (HRP), was injected into the vascular system of the frog, Rana pipiens. Pinocytotic vesicles were seen along plasma membranes of the stellate cells abutting the pericapillary spaces between the pars intermedia and pars nervosa. The HRP was seen within both the pericapillary spaces and these pinocytotic vesicles. In addition, the HRP was very prominent in the extracellular spaces between adjacent stellate and/or MSH cells and around nerve endings and thus, appeared to move from the vascular spaces and into the interior of the pars intermedia. Therefore, the poorly vascularized pars intermedia may have such a route for transfer of materials throughout the gland.
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  • 31
    ISSN: 1432-0878
    Keywords: Glial Cells ; Cyclic AMP ; Differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Modifications of cell shape induced in cultured newborn rat astroblasts by serum deprivation or dibutyryladenosine 3′–5′ monophosphate (dBcAMP) are described. Serum suppression modifies the adhesivity of the cells to the substrate, but this modification is not consistent with a true differentiation. The main ultrastructural feature of dBcAMP-treated astroblasts is the presence of an extensive system of 90 Å microfilaments, while control cells are relatively devoid of these structures.
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  • 32
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    Cell & tissue research 172 (1976), S. 133-144 
    ISSN: 1432-0878
    Keywords: Cornea ; Nerves ; Rat ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the corneal nerves of the rat was studied in tissue fixed by immersion in and by perfusion with glutaraldehyde-containing fixatives. Of the four types of axonal terminal identified in the nerves, those with the features of adrenergic and cholinergic terminals were confined to the nerves at the limbus and were concentrated in the perivascular plexuses. The remaining two types of terminal were found on axons located in all parts of the cornea and on both intraepithelial axons and axons in the stromal nerves. Of these, one contained the numerous mitochondria which occur in the terminals of axons associated with known mechanoreceptors and the second contained variable and often small numbers of both clear and large dense-cored vesicles. While most of the mitochondria-containing terminals were seen in nerves located near the periphery, vesicle-containing terminals were numerous in all of the nerves, and especially in those in the avascular cornea. In material fixed by immersion in glutaraldehyde-paraformaldehyde, the vesicle-containing terminals appeared to be dilated, but in material fixed by perfusion there was little evidence of any increase in the diameter of the axons in the terminal regions. The structure of the terminals was compared with that of the terminals of axons identified in the nerves of the skin and the urinary tract and the differences in the vesicle content of the terminals to those reported in other studies of the corneal nerves was related to the use of different fixation procedures. The possibility that axons possessing such terminals are identical with the beaded axons and both the cholinesterase-positive and fluorescent axons demonstrated in light microscopical studies of the corneal nerves is discussed, and the widespread distribution of the axons in the cornea is equated with the hypothesis that they are afferent in nature and represent the peripheral receptors for pain impulses.
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  • 33
    ISSN: 1432-0878
    Keywords: Epididymis ; Rabbit ; Organ culture ; Androgens ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the corpus epididymidis of the rabbit has been studied following organ culture. Various modifications of tissue preparation and culture conditions were examined to obtain good maintenance of cellular integrity as well as to preserve sperm fertilizing ability. After 5 to 7 days in culture in the absence of hormonal support, the epididymal epithelium showed signs indicative of cellular regression. Such changes included shrinkage of the cells, loss of the border of stereocilia, decrease in smooth endoplasmic reticulum, and an increase in autophagic vacuoles. The presence of androgens in culture media prevented cellular regression to varying degrees, depending on the hormone utilized. With regard to maintenance of cellular integrity, potency of the androgens tested was as follows: 5α-dihydrotestosterone 〉= 3α-androstanediol 〉 testosterone 〉 3β-androstanediol. Addition of insulin to dihydrotestosterone-containing cultures resulted in no improvement in maintenance. Phagocytosis of spermatozoa by epithelial cells was observed in cultured tubules and the degree of spermiophagy was inversely proportional to successful maintenance of fine structural characteristics of epithelial cells. The morphological findings reported here correlate well with the fertilizing ability of spermatozoa from cultured epididymis as reported in an accompanying communication.
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  • 34
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    Journal of Morphology 150 (1976) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 35
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    Journal of Morphology 150 (1976), S. 19-58 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A thin, compressible, lateral suture and ventral plate overlap permit limited movement of the thick and rigid dorsal and ventral plates of Fuscouropoda agitans. Seven pairs of large dermal glands debouch onto the surface. Trochanteral rotation permits defensive leg adpresion and an insectan type of ambulation. The complex hypopharynx-pedipalpal-coxae has a buccal and cheliceral cavity separated by an atriculated epipharynx. The pharynx is Y-shaped in cross section. Extensive paired salivary glands lie above the very long and dexterous 3-segmented chelicerae, and a large pair of coxal glands debouch on coxae 1. From four blunt-ended tracheae, bundles of unbranching tracheoles extend in specific tracts to all organs. The ventriculus is small with three pairs of large caeca; a tightly packed single layer of digestive cells individually enlarged to absorb-phagocytize and digest the food. A typical mesostigmatid excretory tube is present. A typical acarine synganglion is present; mixed nerves have a basal swelling. A postulated neurosecretory organ arises from the pedipalpal nerve. The oocytes enlarge within funicular stalks from the walls of the small median ovary. A large spermatophore is stored in the seminal vesicle; fertilization occurs during oviposition. A tension hinge partially opens both male and female genital plates; closure effected by muscles acting on very long genital plate apodemes. Within sequentially produced spermatogonial cysts of the testes, meiosis is completely synchronous. A large, multilobed male accessory gland produces a large volume of seminal fluid; a mixture of at least four secretions. The origins and msertions of the body wall, genital organ, digestive tract, mouthpart and leg muscles are listed and illustrated. A comparison of anactinotrichid and actinotrichid mites indicates fundamental and consistent morphological differences in aspects of the cuticle, leg articulations, digestive system, excretory system, reproductive system and coxal glands.
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  • 36
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    Journal of Morphology 150 (1976), S. 279-297 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An investigation of the structure of the iridescent scales of the green hairstreak, Callophrys rubi, reveals an internal lattice which is probably cubic close-packed in form. We present a model which explains the formation of the lattice in terms of packing of spheres and surface tension forces and generalize these results to internal structures in other Lepidopteran scales.
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  • 37
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: There are 36 to 42 taste bristles on each half of the labellum of Drosophila melanogaster; most of them are two-pronged with a pouch between them. Some end bluntly with a pore at the tip.Each taste-bristle has two lumina: one is circular, the other crescent-like in cross section. In most bristles four dendrites of chemoreceptor neurons run along the circular lumen. In five to seven taste-bristles only two chemoreceptor neurons are found. A mechanoreceptor neuron sends a dendrite to the base of each taste-bristle.The dendrites are surrounded by four concentrically-arranged sheath cells. The inner cell secretes the cuticular sheath; cells II and III are presumably two trichogens, one secreting the bristle material around the circular lumen, the other around the crescent-like lumen. Cell IV, especially rich in bundles of microtubules, secretes the cuticle of the socket, and corresponds to the tormogen. The neurons have the typical structure found in insect sensilla. In many sensilla one neuron is less electron-dense than the others and may be the water-sensor.On the medial side of the labellum between the pseudotracheae are rows of taste pegs covered by folds. In each peg one chemoreceptor and one mechanoreceptor are found.The number of axons in each labial nerve agrees with the total number of dendrites in all taste organs of each lobe.
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  • 38
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    Journal of Morphology 150 (1976), S. 359-368 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Stereological analysis of the ultrastructural composition of the pulmonary alveolo-capillary region of mice living at sea level compared with that of the same species (Phyllotis darwini) genetically adapted to life at 4,660 m reveals a trend at high altitude towards a greater volume percentage of tissue components. On a weight-specific basis, non-circulating tissue occupies a significantly greater volume in high-altitude mice, but air space and capillary contents are not correspondingly greater. Since the arithmetic mean thickness of the tissue layers and of the air-blood barrier are the same in the two altitudinal groups, the average alveolus must have a smaller volume in the high-altitude mice.Epithelial, endothelial, and erythrocyte surface areas per gram body weight are significantly greater in the high-altitude mice.Nuclear counts indicate that the larger lungs of mice adapted to high altitude are due to larger Pneumocyte I and II and endothelial cells rather than to an increase in the number of these cells. Hematocrits measured within the pulmonary capillaries in the two altitudinal groups were equal.An heretofore unrecognized feature of possible adaptive value is the surface/volume ratio of erythrocytes, which is similar for erythrocytes in alveolar space of mice at low and high altitudes but within lung capillaries is 14.7% greater at high altitude.
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  • 39
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    Journal of Morphology 150 (1976), S. 369-397 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Successive tracheal cuticles of the dorsal longitudinal trunks are studied with the electron microscope. Minor differences seen at the light microscope level are seen as major qualitative and quantitative ones at the ultrastructural level. The larval and pupal cuticles are secreted by similar epithelial cells; these possess large polytene chromosomes. Cell division and possibly cell replacement occur prior to adult cuticle secretion. The findings are discussed in terms of cell specificity, intra- and inter-cellular pattern formation. This simple epithelium, the individual cells of which are capable of producing different cuticles, is interesting since the system is also shown to be responsive to hormone application.
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  • 40
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    Journal of Morphology 150 (1976), S. 453-461 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Eggs of the common snapping turtle, Chelydra serpentina, were incubated at constant temperatures ranging from 20°C to 30°C, At hatching, the oviducts were absent or incomplete in males; the testes were differentiated. In females at hatching, the oviduct was intact hut in some cases the gonad retained bisexual characteristics. Three months after hatching, the ovary was differentiated and contained follicles. Eggs incubated at 20°C and at 30°C developed into females in 100% of the cases. At 26°C, 99% of the individuals were males; at 24°C, 100% were males. More males than females developed at incubation temperatures of 22°C and 28°C.
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  • 41
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: New blastozooids of Polyzoa vesiculiphora, the polysytelid ascidian are produced by pallial budding of three types depending on the method of “isolated bud” formation; stolonic, planktonic and intermediate types. Differences among each type of bud are attributed to behavior of test-vessels composing a part of the bud. Isolated buds produced by each type are essentially equal in terms of their internal structures and their subsequent fate, and develop independently of their parent zooids. New test-vessels originate directly from the epidermis of a “prefunctional zooid,” while the test-vessels derived from the parent zooid finally disintegrate. The new test-vessels extended with branching under the ventral side of a “functional zooid,” ascend to the lateral side of it and participate in bud formation. Budding regions exist in three dimensions on the lateral wall of the mantle of the functional zooid, especially the right posterior part. During the life cycle of one functional zooid, the stolonic type buds appear at early and/or aged stages. Appearances of the stolonic type buds in early stages tend to repress those of the planktonic types. The number of planktonic type buds formed on a functional zooid at the same time is many more than that of the stolonic type. Such budding features are discussed from the viewpoint of behavior of the test-vessel system.
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  • 42
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    Journal of Morphology 150 (1976) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 43
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    Journal of Morphology 150 (1976), S. 763-783 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of a well studied insect chemosensory unit is presented in this report. Two separate lumina are present in this chemosensory unit, the trichogen and sensillar lumina. The fluid within the trichogen lumen exclusively bathes the dendritic terminals, and may be involved with the reception and/or modulation of environmental stimuli. Cytoplasmic extensions of the trichogen cell which line the trichogen lumen may be involved in the production of the cuticular sheath. The sensillar lumen is bordered by the tormogen and a sleeve cell, and is continuous with the unoccupied channel of the setal shaft. Functions for the various cellular components of the blowfly chemoreceptor sensillum are offered.
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  • 44
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 45
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    Journal of Morphology 148 (1976), S. 287-303 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The extrinsic ovarian blood vessels were studied in 134 ewes. In view of recent evidence that uterine luteolysis may involve local veno-arterial transfer of prostaglandin F2α in the ovarian pedicle, particular attention was paid to the interrelationships between veins and arteries.The ovarian artery and utero-ovarian vein are large vessels of conventional structure and lie in close apposition. Their walls are slightly thinner on their apposing sides. The ovarian branches of the ovarian artery are very tortuous, and closely intertwined with the plexiform ovarian branches of the utero-ovarian vein.An extensive plexus of small veins surrounds the ovarian artery and its ovarian branches. Within this plexus are many thin-walled, dilated regions, interspersed with narrow, thick-walled segments. Valves are inconstantly present at sites of entry of branches of the plexus into the major veins. Small numbers of arterio-venous anastomoses are present in the distal part of the ovarian pedicle.Unless blood can flow in a veno-arterial direction through arterio-venous anastomoses or capillary beds, the structural barrier between uterine venous and ovarian arterial blood is substantial.
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  • 46
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hypotrichs are among the most complex ciliates in terms of morphology and development. To study the fine structure of cortical morphogenesis associated with cell division in Euplotes eurystomus, three different methods of observation were employed: light microscopy of protargol-stained specimens, scanning electron microscopy of cells prepared by critical point drying, and transmission electron microscopy of sectioned material. Observations on the stages of morphogenesis give much new information about cortical development, particularly about proliferation and aggregation of kinetosomes (basal bodies), ciliary outgrowth, the topography of morphogenesis, cirrus resorption, and growth of the pellicle. During the formation of new cirrus the process of kinetosome proliferation is atypical, i.e., groups of prokinetosomes are seen oriented at random and, in some cases, prokinetosomes apparently are formed at a distance from nearby young kinetosomes. That the new cirri develop in surface grooves, the grooves elongate into “tracks,” and (in some cases) grooves are partitioned into separate tracks suggests that the grooves play a role in the orderly migration of the new cirri on the cell surface. Conspicuous morphogcnctic changes in the cell surface involve local growth of the pellicle. The process of pellicle growth apparently involves two basic steps: (a) growth of the outer cell membrane to form “bare regions,” and (b) formation of alveoli in the bare regions. Alveolar sheets are formed by fusion of alveolus precursor particles. Cirrus resorption is sequential over several stages of development, and old cirri are resorbed as the new cirri impinge on them. As the old cirri regress, both in situ resorption and retraction of axonemes into the cytoplasm occur.
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  • 47
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    Journal of Morphology 149 (1976), S. 33-51 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mature annelid cuticle contains orthogonally oriented collagen in a matrix capped superficially by a dense epicuticle with external corpuscles. The underlying epidermis is a simple columnar epithelium with two major cell types, mucous-secreting cells which secrete through channels in the cuticle to the exterior of the worm, and “supportive” cells which presumably produce and increase the cuticle by secreting into it.The structures of supportive cells, previously interpreted as specialized for establishing interfibrillar collagen order, are revealed by glutaraldehyde fixation as common cellular components without the qualities deemed useful to align collagen. Cell processes which penetrate and sometimes pass completely through the cuticle are not stable, not in geometric order, and lack cilia-like structure. Cilia, unlike the ubiquitous cellular processes, are highly restricted to regions of the epidermis with specialized functions. Cellular control, or other control, of collagen fibrillogenesis remains unestablished.
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  • 48
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    Journal of Morphology 149 (1976), S. 1-31 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cibarial food pumps of aquatic Heteroptera contain specialized epipharyngeal triturating devices. In the Naucoridae, striated bands and transverse plates triturate particles against the underlying hypopharynx. Anterior to them lie a pair of oblique folds which play an accessory role. The gross morphology of these devices is very similar in representatives of five genera of typical Naucoridae (Ambrysus, Pelocoris, Limnocoris, Cataractocoris, Cryphocricos) and differs from that of the atypical genus Aphelocheirus.The scanning electron microscope reveals additional differences between Aphelocheirus and the typical genera as well as variations, among the latter, which are not visible with the stereoscopic microscope. The oblique folds of the typical Naucoridae are well developed and contain processes for trapping particles; in three genera the region posterior to the folds is also modified. In Aphelocheirus only the latter region appears to trap particles, and the oblique folds are smooth and weakly developed. The striated bands of all genera bear ventral ridges arranged into transverse zones with precise patterns. The fourzoned bands of Aphelocheirus have a very different pattern than the two-zoned bands of the other genera. Among the latter, Cryphocricos has a simpler pattern of ridges than the other typical Naucoridae. The ventral surfaces of the transverse plates are highly modified in Aphelocheirus and less so in the other genera; those of Cryphocricos differ from those of the other Naucoridae.The fine structure of the cibarial epipharynx supports the views of some systematists that (1) Aphelocheirus should be placed in the monogeneric Family Aphelocheiridae rather than in the Naucoridae, (2) Cryphocricos represents a different subfamily than the other four typical Naucoridae, and (3) Cataractocoris belongs in the same subfamily as Ambrysus rather than with Cfyphocricos.
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  • 49
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    Journal of Morphology 149 (1976), S. 53-71 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Appearance of collagen fibrils in the cuticle was seen by electron microscopy to be preceded by fonnation of a finely filamentous matrix material. At first, the fine filaments of the matrix are unorganized. However, signs of orthogonal ordering soon appear in the most superficial portion of the cuticle, and subsequently appear more basally and closer to the underlying epidermis. Meanwhile, fibrils of different staining properties and identifiable as collagen begin to be deposited in the superficial portion of the cuticle, the same region which first showed organized fine filaments. Then, like the fine filaments before them, the collagen fibrils polymerize more basally. Collagen appears to polymerize on the preformed skeleton of fine filaments as though the fine filaments caused the collagen to assemble. Neither the polymerization nor ordering of collagen fibrils seems to require direct cellular intervention but occur first in that portion of the cuticle which is furthest away from the underlying epidermis. The fine filaments may be self ordering, extracellular macromolecules which in turn determine the polymerization of collagen fibrils.
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  • 50
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    Journal of Morphology 149 (1976) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 51
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    Journal of Morphology 149 (1976), S. 159-182 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this paper the cranial arteries, cranial arterial foramina, and bony canals of the Cheloniidae, Chelydridae, Pelomedusidae, and Chelidae are described in detail. From skull studies and published material, the general cranial arterial patterns of all the turtle families can be inferred. Sea turtles, the Cheloniidae and Dermochelyidae, possess both a large stapedial artery and a large artery supplying the orbit, which is possibly similar to the primitive cranial arterial pattern for turtles. From a primitive pattern in which stapedial and palatine arteries supply the orbit, the Chelydridae and Testudinidae retained a large stapedial artery and reduced the palatine artery, while the Kinosternidae and Dermatemydidae developed a large palatine artery and reduced the stapedial artery. The Trionychidae and probably the Carettochelyidae evolved a complex arterial pattern in which the stapedial artery was reduced somewhat and the pseudopalatine artery was substituted for the palatine artery. Pleurodires in general retained a large stapedial artery and reduced or eliminated the palatine artery. The Podocneminae, including the Madagascar species, developed a highly modified carotid canal, which is found in no other turtle group. The facts which have been presented should aid in fossil skull studies and in understanding the evolutionary background of recent turtles.
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  • 52
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    Journal of Morphology 149 (1976) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 53
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    Journal of Morphology 149 (1976), S. 223-241 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Proliferative and migratory changes of lymphoid cells in the spleen were observed in turtles stimulated with KLH and maintained at 30°C. Small foci of pyroninophilic lymphoblasts were first seen in the white pulp at about day 5. Progressive enlargement of these centers continued and peaked by days 8-12. By days 15-20 the white pulp returned to a normal (unimmunized) state, while the number of pyroninophilic cells, primarily plasma cells, increased markedly in the red pulp. At days 22-25, the number of plasma cells returned to normal levels and the spleen appeared normal for the remainder of the 60 day observation period. These events suggest that at 30°C,-the turtle is capable of a strong and prompt proliferative response in the white pulp sheaths, followed by migration and differentiation of lymphoblasts into plasma cells, n the red pulp., Observations of pyroninophilic cells in sinuses, venules and veins of the spleen and a concomitant depletion of cells in red pulp, further suggest a migration from the spleen to other sites.Following a second antigenic challenge, at day 60, no significant histological changes were observed at 30°C. Nor were any changes observed following primary or secondary antigenic challenge, in animals maintained at 10°C. These findings are discussed with regard to immunological memory and low temperature immunosuppression in ectothermic vertebrates.
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  • 54
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    Journal of Morphology 149 (1976), S. 243-263 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the ultrastructural comparison of normal, unimmunized spleens with immunized spleens at key intervals after antigenic stimulation with keyhole limpet hemocyanin (KLH), we noted cellular and cytological features which reflect the cellular kinetics of the primary immune response, particularly with respect to plasma cell production. Although lymphoblasts and mature plasma cells are present in the white and red pulp, respectively, intermediate stages of the plasma cell line are rarely found in normal spleen. Following antigenic challenge, we found a marked increase in lymphoblasts in the white pulp, most of them containing short segments of rough endoplasmic reticulum suggesting initial differentiation toward plasma cells.Following an apparent migration of cells from the white to the red pulp, we found plasma cells in various stages of maturation in the red pulp cords and sinuses. The ultrastructural features of these cells reflect 'the differentiation of lympho blasts into mature plasma cells. Both immature and mature plasma cells usually possess dilated cisternae of rough endoplasmic reticulum, suggesting that they are capable of producing and storing a secretory product, presumably antibody. We also noted a large number of immature macrophages and monocytes in immunized spleens. These cellular events and their cytological characteristics are compared to those described in other vertebrate classes.
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  • 55
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The anatomy and ultrastructure of the lizard kidney (Sceloporus cyanogenys) have been studied by light and electron microscopy. The number of glomeruli was counted' in serial sections and estimated to be 2,000 (in the two kidneys). Beginning with the glomerulus and Bowman's capsule the nephron segments are sequentially: (a) proximal tubule; (b) intermediate ciliated segment consisting of a proximal and distal part; (c) distal tubule, which can be divided into two segments, followed by (d) connecting tubule and (e) initial collecting duct. The initial collecting ducts from several nephrons open into the collecting duct. Tubular epithelium in this lizard has similarities to that of other reptiles, The lateral borders do not overlap like in mammals, but interdigitate by fingerlike projections. The length of the nephron segments was measured in disected tubules and the diameter was measured on light and electron micrographs. From these measurements estimates of inner tubular surface area were made. Together with data from physiological studies (Stolte et al., '76; Schmidt-Nielsen, '76) the estimated surface area was used to calculate transport rates per unit area across the epithelium. Comparisons of structure and transport rates were made between S. cyanogenys and other reptiles and mammals.
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  • 56
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ethidium bromide (l0 μg/ml) and bromodeoxyuridine (25 μg/ml) were used to sensitize selective cell organelles to visible wavelengths of an argon ion Her (488 and 514 nanometers). Ethidium bromide was shown to be salabtlve In sensitizing nucleoli, chromosomes, and the centriolar region of PTK2 cells to the laser microbeam. Similarly, BrDU sensitized chromosomes to the microbeam irradiation. The lesions produced on the chromosomes when either agent was used appeared as a phase paling of the irradiated segment. Nucleolar lesions also appeared as a phase paling, and the centriolar region alteration appeared either as a phase paling or a phase darkening.
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  • 57
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Larval Typhlotriton spelaeus collected from five caves in Pulaski Co., Missouri, were kept as larvae or induced to transform in darkness or continuous fluorescent illumination. Larvae maintained in darkness for 215 and 279 days had smaller eyes, smaller rod inner and outer segments, and fewer metaphase figures in the genninative zone of the neural retina than comparable larvae maintained in light (258 lux). Except for visual cell size, differences were small and for each characteristic exceptions were observed. One larva kept in light showed early retinal degeneration comparable to that in transformed adults of T. spelaeus. All larvae exhibited optomotor behavior both before and after the experiment.Among animals induced to transform by L-thyroxin and maintained in darkness 111 to 366 days, visual cell and pigment epithelium degeneration was more extensive and more frequent than in animals kept for the same length of time in light (237-298 lux). In darkness the frequency of animals with retinal degeneration increased between 111 and 366 days. In light some animals exhibited pigment epithelium reduction with normal visual cells, and others had free, pigmented cells in the subretinal space. These effects were not comparable to degeneration in darkness. Eyelids covered the eyes of only a few animals in both light and dark treatments. The extent of eyelid encroachment over the eye was greater in darkness than in light. Most animals exhibited optomotor responses after experiments, but responses of animals kept in darkness were impaired in comparison to those of animals kept in light.
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  • 58
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    Journal of Morphology 150 (1976), S. 321-326 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Exercise affects the growth of the dorsal longitudinal flight muscles in the tsetse fly. Examination of electron micrographs of flight muscles taken from flies subjected to enforced exercise, “ormal” exercise and no exercise reveals that both mitochondrial and myofibrillar fractions of the muscles are stimulated to grow at a faster rate by enforced exercise but that the mitochondria respond more rapidly.
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  • 59
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ultrastructure and shell formation in the testaceous ameba, Lesquereusia spiralis, were investigated with both scanning and transmission electron microscopy and X-ray microanalysis. The nucleus, surrounded by a fibrous lamina, contains multiple nucleoli. The cytoplasm, containing a well developed granular endoplasmic reticulum, also contains remnants of starch granules in stages of digestion. Spherical aggregates of ribosome-like particles may be seen. Golgi complexes seem to produce both a nonordered fibrous material and an electron dense vesicle. Only the latter appears to bleb off from the Golgi complex. X-ray microanalysis demonstration of silicon in Golgi vesicles and in some dense vesicles suggests that the fibrous component of the cisternae may take up and concentrate silica to form the electron-dense component of the vesicles. Membrane-bound siliceous crystals are often seen adjacent to the Golgi, suggesting either a Golgi origin or platelet formation in vesicles after release from the Golgi complex. Both electron-dense bodies and siliceous platelets are released from the cell by a process similar to apocrine secretion and may be seen outside the cell in route to the shell during shell morphogenesis. Shell development involves fusion of electron-dense bodies to form a matrix, positioning of siliceous platelets in this matrix parallel to the shell surface, and development of a system of matrix chambers. A particulate glycoconjugate is released to the shell surface upon rupture of the matrix chamber.
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  • 60
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    Journal of Morphology 150 (1976) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 61
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A staging system has been devised for normal regeneration from the upper arm in the mature axolotl. It consists of seven externally definable stages: (1) Wound healing (WH); (2) Dedifferentiation (DD); (3) Early bud (EB); (4) Medium bud (MB); (5) Late bud (LB); (6) Palette (Pal), and (7) Digital outgrowth (DO). Serial histological sections of 38 regenerating limbs were used to correlate gross stages with microscopic events in the regenerative process.
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  • 62
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    Journal of Morphology 150 (1976), S. 639-679 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Anatomical components of afferent innervation in the rim of the octopus sucker are described. In the sensory epithelium under the smooth cuticle two associated ciliated receptor cell-types (presumably chemosensitive) occur in clusters. A third ciliated receptor cell-type under the toothed cuticle may be a mechanoreceptor. A non-ciliated receptor cell-type of unknown function, under the toothed cuticle, is characterized by a microvillus-lined apical canal containing dense granular material. The axons of the latter two receptors go directly into large nerve tracts which nm through the infundibular muscle and on to the ganglion of the sucker. The axons of the first cell-types terminate on interneurons either in the base of the epithelium or below the epithelium. All the interneurons of the basal region of the epithelium migrate centripetally and develop into encapsulated interneurons. Within the epithelium, fine fibers provide collateral contact among cluster receptors. Collateral interaction among basal and encapsulated interneurons occur in the infundibular plexus. The microanatomy of the rim of the sucker suggests that chemosensory cues are funneled into the interneurons where they are concentrated into integrated signals, while other sensory input is probably sent directly to the ganglia of the sucker and/or arm.
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  • 63
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The blood cells in the bud and the zooid of the polystyelid ascidian, Polyzoa vesiculiphora, were examined by means of light and electron microscopy to identify the cells that have been named trophocytes. The large blood cells were abundant in the mesenchymal space of the bud, but not in that of the functional zooid. They contained glycogen particles, lipid droplets, large protein granules and autophagosomes in their cytoplasm and were identified as granular amoebocytes. The majority of these cells were specifically phagocytized by phagocytes during bud development and disappeared. These results indicate that the granular amoebocytes virtually represent trophocytes in Polyzoa and may participate in bud development via nutrient supply to the developing tissues.
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  • 64
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    Journal of Morphology 150 (1976), S. 681-709 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Timed pregnancies were obtained in Sprague-Dawley rats and early ultrastructural differentiation of myocardium of embryos of 10, 11, 12, 13, and 14 days was investigated and compared with that of newborn. Ten-day myocardium is characterized by loosely packed cells; the cytoplasm is typified by a dearth of organelles. Both thick (myosin) and thin (actin) filaments become identifiable for the first time in the 10-day myocardium where the heart is pulsating but circulation is not established. These filaments are not visible in the embryos of 9-day-old myocardium. The formation of these filaments is observed to continue throughout the period covered in this investigation. Concomitant with the appearance of the myofilaments is the synthesis of Z band material. By the eleventh day of gestation and during the subsequent days there is a rapid proliferation and differentiation of most of the organelles. The myofilaments become organized into fully formed striated fibrils. Intercalated discs appear as. small wavy lines on the eleventh day and become plicated in later stages and serve as cell boundaries and points of attachment for myofilaments and fibrils. There is a perceptible change in the number and morphology of mitochondria from the tenth to eleventh day and later stages of development when the heart becomes functional. Similarly, there is a rapid proliferation and differentiation of granular endoplasmic reticulum and Golgi bodies. Large quantities of free ribosomes are dispersed in the cytoplasm of 10-day myocardium; however, in later stages there is a progressive reduction in the distribution of these particles. An intimate association of ribosomes and polysomes with the developing myofibrils is discernible. The T -system and sarcoplasmic reticulum begin to appear in II-day myocardium. The embryonic myocardium displays intense mitotic activity throughout its development and a unique feature of embryonic myocardial cells is the simultaneous occurrence of myofilament synthesis and mitotic activity within the same cells.
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  • 65
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    Journal of Morphology 150 (1976), S. 711-725 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of midgut cells in two species of Cladocera (Crustacea: Branchiopoda) has unique features when it is compared to that in the midguts of other arthropods. Features which suggest that food is absorbed in digested form are: the presence of the peritrophic membrane, the glycocalyx, the almost complete absence of pinocytotic vesicles, and the large surface area of a great number of microvilli. Digested products presumably pass into the hemolymph through the network of extracellular canals and cisterns surrounding the basal ends of intestinal epithelial cells. Cells of the midgut in Cladocera differ from those of other arthropods in the simplicity of their basal plasma membranes, which are not highly folded. The small number of membrane invaginations suggests that water reabsorption is very slight, as is the usual condition in aquatic animals.The origin and evolution of peculiar structures we call “multivesicular-like bodies” have been investigated. These display a variety of different morphological features. Some contain acid phosphatase activity and are considered as specialized lysosomes.
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  • 66
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    Journal of Morphology 148 (1976), S. 23-31 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When cervical segments 14 to 15 of the chicken spinal cord are cut transversely and studied by routine histological and histochemical methods, an onion-shaped region, filled with thread-like fibers, if seen to surround the ependymal cells of the central canal and to be bounded laterally by the neural elements of the spinal gray matter. This area is negative for succinic dehydrogenase, beta-hydroxybutyrate dehydrogenase and cholinesterase activity, but very strongly periodic acid-Schiff positive. Diastase controls show the positive material to be glycogen. Parasagittal sections through this cervical region and into the upper thoracic cord, show the glycogen-rich region to extend longitudinally throughout the region. Because of its location and histochemical characterization, which, He similar to that of the ventral portion of the glycogen body, the term brachial glycogen budy is proposed for this structure.
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  • 67
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    Journal of Morphology 148 (1976), S. 1-21 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Anterior dorsal ventricular ridge (ADVR) is a major subcortical; telencephalic nucleus in snakes, Its structure was studied in Nissl, Golgi, and electron microscopic lrerarations in several species of snakes. Neurons in ADVR form a homogeneous population. They have large nuclei, scattered cisternae of rough endoplasmic reticulum in their cytoplasm, and bear dendrites from all portions of their somata. The dendrites have a moderate covering of pedunculated spines. Clusters of two to five cells with touching somata can be seen in Nissl, Golgi, and electron microscopic preparations. The area of apposition may contain a series of specialized junctions which resemble gap junctions. Three populations of axons can be identified in rapid Golgi preparations of snake ADVR. Type 1 axons course from the lateral forebrain bundle and bear small varicosities about 1 μ long. Type 2 axons arise from ADVR neurons and bear large varicosities about 5 μ. long. The origin of the very thin type 3 axons is not known; they bear small varicosities about 1 μ. long. The majority of axon terminals in ADVR are small (1 μ. to 2 μ long), contain round synaptic vesicles, and form asymmetric active zones. This type of axon terminates on dendritic spines and shafts and on somata. A small percentage of terminals are large, 5 μ in length, contain round synaptic vesicles, and form asymmetric active zones. This type of axon terminates only on dendritic spines. A small percentage of terminals are small, contain pleomorphic synaptic vesicles, and form symmetric active zones. This type of axon terminates on dendritic shafts and on somata.
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  • 68
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    Journal of Morphology 148 (1976), S. 33-63 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tooth development and replacement in fetal and adult viviparous caecilians (Amphibia: Gymnophiona) are described and analyzed according to current theories of tooth succession. The fetal dentition differs from that of the adult in morphology, position, and function. Teeth are used by fetuses to scrape the oviducal epithelium, thus stimulating the secretion of a nutrient substance. Fetal dentitions vary in morphology and position in different species. The ontogeny of teeth of several species is described and the patterns of addition of loci and of replacement are analyzed, Loci are added both posteriorly along the jaw and between existing loci as the jaw grows prior to ossification; subsequently addition is restricted to the posterior part of the jaw. Tooth replacement is alternate. The several rows and patches of teeth are the result of retention of replacement series on the dentigerous elements. Tooth development and replacement in a series of juveniles and adults of different sizes in a single species are also considered. Post-fetal patterns of development and replacement are similar to those seen in larvae and adults of oviparous species. Variation in numbers of teeth and proportions of teeth at particular stages occurs ontogenetically and among individuals of the same size, though proportions occur in a similar pattern throughout the series. The general pattern of tooth replacement in fetuses and adults can be explained by either Edmund's Zahnreihen theory or by Osborn's Tooth Family theory, but replacement in fetal tooth patches and the fetal-adult dentitional transition are explained by neither.
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  • 69
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    Journal of Morphology 148 (1976) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 70
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    Journal of Morphology 148 (1976), S. 137-159 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The gross and microscopic anatomy of the venom producing parotoid glands of Bufo alvarius has been studied by light and electron microscopy. Histochemical reactions for the presence of venom constituents and of components in biochemical pathways in the synthesis and release of venom were performed. The gland is composed of numerous lobules. Each lobule is an individual unit with a lumen surrounded by a double cell layer. Microvilli of the outer layer interdigitate with microvilli of the inner layer. Cells of the outer layer resemble smooth muscle cells, are rich in adenosine triphosphatase and glucose6-phosphatase, and contain numerous pinocytotic vesicles, glycogen granules and various organelles, These organelles include “crystalloids” of what seem to be highly organized agranular reticulum. These outer layer cells probably function in some aspects of venom synthesis, active cellular transport and contraction in the discharge of the secretory product. The inner cell layer demonstrates a positive chromaffin reaction, contains steroid material, various organelles, some pinocytotic vesicles and glycogen granules, and appears devoid of a plasmalemma on its inner surface. This layer is probably involved in venom formation and release via an apocrine type of secretion.Bufo alvarius parotoid gland shows significant morphological and histochemical differences from that of B. marinus and more nearly resembles a typical steroid producing organ.
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  • 71
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    Journal of Morphology 148 (1976), S. 177-184 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Small local wounds on the surface of the mouse lung, produced by cauterization, healed by a typical reparative process involving c1 migration and increased cell division in alveolar and bronchial tissues. The local cell division response closely resembled the compensatory cell division response in the same organ which follows unilateral pnemnonectomy or unilateral collapse of the lung: initially there was an increase in the rate of DNA synthesis followed by an increased rate of entry into mitosis, both of these functions returning to normal levels within a few days. It is therefore suggested that both types of response are governed by a single regulatory mechanism. The results do not support the view that the rate of cell division is regulated by systemically-circulating mitotic control factors and it is proposed that changes in the cell division rate, both in the reparative and in the compensatory types of response, are determined by local alterations ill the concentration of regulatory metabolites.The magnitude of the cell division response was much greater in bronchial than in alveolar tissue. a result which is consistent with the view that new alveolar tissue may be produced by the proliferation and differentiation of bronchial cells.
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  • 72
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    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Guinea pig soleus, medial gastrocnemius and vastus lateralis muscles were compared for spindle density and distribution, number of intrafusal fibers per spindle and histochemical appearance of the axial bundle. A total of 326 spindles was used in the comparisons. Spindle density was over four times greater in the soleus than in either the medial gastrocnemius or vastus lateralis. In the soleus the spindles were distributed at random, but in the other two muscles no spindles were found in those fascicles in which fast-twitch glycolytic extrafusal fibers predominated. The average number of intrafusal fibers per spindle varied by less than 5% between the three kinds of muscles. About 80% of all spindles located had four intrafusal fibers, two of the nuclear bag type and two of the nuclear chain type. The histochemical appearance of the axial bundle was the same in each kind of muscle. Based on intensities of the myofibrillar adenosine triphosphatase reaction product at polar regions nuclear bag fibers were separable into two histochemical groups; nuclear chain fibers were of only one histochemical type.
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  • 73
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    Journal of Morphology 148 (1976), S. 193-207 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To establish a morphological baseline for experimental studies of differentiation using the cement gland as a model, the following observations are added to those on record. The elongated cells of Xenopus laevis cement glands have an internal organization displaying five distinct zones differing in structure and specialized function. The apical zone contains packed secretion vesicles apparently belonging to two different types. The transit zone appears to be devoid of major biosynthetic activity and contains secretion vesicles migrating toward the surface. The zone of biosynthesis is typically organized in concentric regions. The very elongated nucleus lies in the next zone. Finally, the storage zone is characterized by lipid droplets and yolk platelets.Only quantitative differences are observed between cells of young and mature cement glands. Though all cells have the same general organization they may probably be divided into two subtypes according to the structure of their cytoplasm. The epithelial cells surrounding the gland differ according to their position along lateral or basal borders.
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  • 74
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    Journal of Morphology 148 (1976), S. 209-225 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of the mature sperm of the holothurian, Cucumaria miniata, and the ophiuroid, Ophiopholis aculeata, is described with particular reference to their acrosomal and centriolar satellite complexes, and compared to the sperm of other echinoderms.In Cucumaria, the acrosome is in the form of a diffuse acrosomal vesicle. It is unusual in that it apparently lacks an acrosomal membrane. A membrane separating the acrosomal vesicle from the periacrosomal material may not be equivalent to a typical inner acrosomal membrane. In Ophiopholis, the acrosome is dense, with some internal substructure, and is enclosed by a complete acrosomal membrane. In both species, the acrosome is partially surrounded by an amorphous periacrosomal mass. There is a notable absence of a subacrosomal depression and associated structures as found in other echinoderm sperm.The centriolar satellite complex (CSC) is essentially identical in both species. A reconstruction of the CSC is presented. The CSC consists of nine satellites radiating angularly from the distal centriole, each bifurcating at a dense node before inserting on a marginal ring containing circumferential microtubules. The ring is probably a cytoskeletal element. Immediately below the satellites are nine Y-shaped connectives. connecting each of the axonemal alpha doublets to the flagellar membrane.
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  • 75
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    Journal of Morphology 148 (1976), S. 227-253 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The functional anatomy of the hindlimb of 12 species of viverrids was studied with relation to locomotion. The animals were allocated to primary locomotor categories on the basis of their anatomy and locomotion.The climbing, arboreal walking category (Nandinia binotata) is characterized by a small sacroiliac articulation, the iliopsoas inserts onto a medially located lesser trochanter and the femoral condyles are not posteriorly placed. The hindfoot is plantigrade and its structure permits considerable movement. The pads are soft and the claws retractile.Representatives of the arboreal and terrestrial walking and jumping category (Genetta genetta, G. servalina, G. tigrina) have a plantigrade forefoot and digitigrade hindfoot. The lesser trochanter is more posteriorly placed than in the climbing category. A previously undescribed muscle, the caudofemoralis profundus extends from several anterior caudal vertebrae to the femur. The tibio-astragular joint restricts supination of the foot. There is little mediolateral movement in the digitigrade foot. The claws are retractile.In the general terrestrial walking and scrambling group (Helogale parvula, Mungos mungo, Atilax paludinosus, Bdeogale crassicauda, Herpestes ichneumon, H. sanguineus) the animals have essentially similar hindlimbs except for size differences and modifications to the feet. Helogale and Mungos have large medial epicondyles on the humerus and large terminal phalanges. Bdeogale has a vestigial first metatarsal, while Atilax can splay its digits. In all species the distal phalanges are non retractile.The trotting category (Civettictis civetta. Ichneumia albicauda) is characterized by longer epipodials and metapodials and a more proximal position of muscle bellies. Most of the adaptations minimize rotation, adduction and abduction of the leg and supination of the foot. The metatarsals are closely adjoined and the distal phalanx is stout and non -retractile.There appear to be two levels of locomotory adaptation. Major adaptations affect the whole appendicular skeleton and are used to assign animals to primary locomotor categories. Minor adaptations occur mainly in the foot and indicate the more specific habits of the animal.
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  • 76
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    Journal of Morphology 148 (1976) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 77
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    Journal of Morphology 149 (1976), S. 121-137 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Early embryogenesis is described for the southern corn rootworm, Diabrotica undecimpunctata Howardi Barber, at 24 ± 1°C. During the first four hours following oviposition, the maturation divisions and syngamy are completed. Morphological changes in the second polar body accompany syngamy. Cleavage divisions and energid migration occur during the fourth to the tenth hour. The vitellophags, which appear during cleavage divisions, are distinguished from the blastema-bound nuclei by having smaller, more densely staining nuclei. After completion of a uniform blastoderm (11-14 hour), cell division ceases until the completion of the germ band and the formation of the embryonic membranes (22 hour). This species has a pattern of amnion formation that is different from most Coleoptera but is shared with a few other chrysomelids, some Isoptera, and some Odonata.
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  • 78
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    Journal of Morphology 149 (1976), S. 105-119 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Each ocellar nerve in the house cricket Acheta domesticus contains giant nerve fibers of 10-15 μ diameter, characterized in Golgi Cox preparations by a single row of short collaterals which runs along nearly the entire length of a fiber. Numerous long collaterals are given off by thin fibers in the ocellar nerve; medium-size fibers give off relatively few collaterals.The lateral ocellar tracts extend posteriorly through the dorsal protocerebrum, crossing the protocerebral bridge dorsally. The smaller median ocellar tract runs more ventrally through the pars intercerebralis; posterior to the bridge its fibers turn out toward the lateral nerves. Golgi and cobalt preparations reveal branching of giant and mediu_-size ocellar fibers posterior to the bridge at two levels, forming bilateral regions of ocellar neuropile. No ocellar processes appear to be given off to the corpora pedunculata, centra! body, nervi corporis cardiaci, antenna! lobes, or circumesophageal connectives; it is uncertain whether ocellar collaterals extend into the protocerebral bridge or optic lobes. Cell bodies of giant and medium-sized fibers are located in the pars intercerebralis.
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  • 79
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    Journal of Morphology 149 (1976), S. 547-565 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The labial gland of the adult sphingid moth, Manduca sexta, is composed of five distinct regions, each made of a single cellular type. Four of these regions are derivatives of the single specialized cellular population that makes up the caterpillar labial duct.Both the larval labial duct and its derivatives are large, polyploid cells with pleiomorphic nuclei. There is a definite cellular continuity between the larval and adult forms of these cells throughout metamorphosis; no mitoses or cell deaths are seen to occur in the gland during transformation.Cytological studies indicate that in the process of cell transformation the ducts first “dedifferentiate,” elongate, then redifferentiate. Intermediates in this process have well defined structures which should make this system useful in studying covert events in the transformation process.
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  • 80
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    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The infracerebral gland of Nereis is made up of three types of cells. C1 cells are hypertrophied pericapsular elements, whereas C2 and C3 cells have the morphological and cytological features of neurosecretory neurons. C2 and C3 cells give rise to centripetal “proximal processes” which extend into the brain through the midventral pocket formed by delamination of the brain capsule. Their “distal processes” terminate within the gland or its immediate vicinity. “Centrifugal fibers” arise from nerve cells located within the brain and appear to synapse upon the proximal processes of C2 cells in the region of the midventral pocket and in the ventral region of the brain. The cytology of C2 and C3 cells suggests that they are the source of distinct peptide hormones.
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  • 81
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    Journal of Morphology 150 (1976), S. 79-115 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pectoral myology and osteology of the cyprinoids Notemigonus crysoleucas, the golden shiner, and Catostomus commersonnii, the common white sucker, resemble those of generalized, lower teleosts in structure and function, except in features related to the manipulation of the massive fifth ceratobranchial of cyprinoids by muscles attaching on the girdle. Catostomus is more specialized in having unique intercostal muscles to the girdle, complex subclavian arteries and lack of a superficial trapezius muscle. The bony pectoral anatomy of the siluriform, Ictalurus nebulosus, the brown bullhead, is highly specialized in relation to the presence and locking of the massive pectoral spine which is formed of fused dorsal and ventral propterygial rays; there is consolidation of the girdle through fusion of bones, presence of unique stabilizing bony structures, firm symphyseal union of bilateral girdles and the presence of friction-surfaces of girdle and spine for locking. The movements of the spine are specialized in the greater guidance offered by the girdle. Myological specializations are related mainly to ventral appendicular muscles which lock the spine. The nervous and arterial systems are generalized.
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  • 82
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    Notes: The inferior lobes of the shark hypothalamus were examined with light, transmission and scanning electron microscopy. The cells bordering the floor of the lateral recess appear to be typical liquor-contacting neurons. With scanning electron microscopy (SEM) the apical ends of these cells are seen to bulge into the ventricular lumen. In contrast, the roof is lined by a more typical ependymal cell characterized by numerous cilia and microvilli. In addition, SEM reveals several kinds of supraependymal cells with processes that appear to penetrate the ventricular lining. A periventricular nucleus underlies the ependymal cells. Neurons of the periventricular nucleus contain numerous lipofuchsin granules. The rest of the inferior lobe consists of many neuronal fibers. The morphology of the hypothalamic inferior lobe is discussed in relation to its possible role in feeding and aggressive behavior in both elasmobranchs and teleosts.
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  • 83
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    Journal of Morphology 150 (1976), S. 423-451 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Stichopus moebii, a sea cucumber, has a closed circulatory system which is unique in its degree of development for the phylum Echinodermata. The gross anatomy, histology and fine structure of the system were studied. Blood vessels consist of a coelomic surface of ciliated epithelium, a layer of muscle and nerve cells, followed by connective tissue and luminal lining of endothelium. Basically the blood vascular system consists of two major vessels running parallel to the gut: the dorsal vessel pumps colorless blood via the vessels within the walls of the intestine into the ventral vessel. There are two specialized areas of the circulation: (1) At the upper small intestine 120 to 150 muscular single-chambered hearts pump blood from the dorsal vessel into a series of intestinal plates. (2) At the lower region of the small intestine the vasculature is associated with the left respiratory tree. Blood passing from the dorsal pulmonary vessel can take two routes to the gut, it either passes through myriads of minute respiratory shunt vessels entangled with the respiratory tree or it passes through a unique follicle network consisting of tiny channels periodically dilated into chambers filled with iron deposits, necrotic cells and developing coelomocytes.
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  • 84
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    Journal of Morphology 150 (1976) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 85
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    Journal of Morphology 150 (1976), S. 299-305 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The neck region of the mature spermatozoon of Discus rotundatus is described. No evidence for a centriole or centriolar derivative is obtained. Nine striated coarse fibres and the two central fibres of the axoneme extend into the base of the implantation fossa. The axonemal doublet system is disrupted in the neck region. There are two fibrous accessory structures located between the central doublet and the striated coarse fibres.
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  • 86
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    Journal of Morphology 150 (1976), S. 307-319 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Explants of 4.5-day-old chick embryonic neuroretinas with mesenchyme were exposed to Methotrexate (MTX) in medium 199 with embryo extract. Proliferative responses of the cultured neuroretinas were followed radioautographically by administration of 3H-thymidine to the cultures. The DNA synthetic, mitotic and pyknotic responses of the ventricular cells of the neuroretina were followed over a 16-hour period. The responses observed suggested that MTX caused a synchronization of the ventricular cells in the pre-mitotic phases with no direct inhibition of mitosis. Furthermore, prolonged exposure to MTX resulted in the accumulation of labeled pyknotic cells, indicating a decline in the regenerative capacity of the proliferative ventricular cells.
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  • 87
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    Journal of Morphology 150 (1976), S. 805-823 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The arrangement of collagen fibers over the body surface in the basement lamella of Pseudaeris and Xenopus tadpoles is described. It can be viewed by scanning microscopy after removal of epidermis and basal lamina by trypsin treatment of alcohol fixed tissue. The orthogonal array is modified in regions where fiber direction changes extensively such as the base of the ventral fin or the posterior part of the head. In these regions “exceptional points” in the orthogonal pattern occur, as described by Rosin (1946). The pattern is bilaterally symmetrical. In the region of the nasal opening the orthogonal pattern is replaced by a mat of randomly oriented fibers. In tail regeneration the wound area is marked by aberrant disposition of collagen anteriorly then a mat of randomly disposed fibers followed posteriorly with a sharp transition to the orthogonal pattern of the regenerate. No fiber terminations could be seen in normal or regenerating regions of the lamella.
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  • 88
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    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Sperm induction pores, tubuli annulati, rami sacculi, sacculus foemineus, cornu sacculus and acantho-membranous hood in female Dermanyssus gallinae support the probability of coxal insemination as reported for some other mesostigmatid species.Development of the circular testis in males (from fusion of two anterolaterally projecting protonymphal testicular arms) and formation of haploid (n = 3) spermatids from haploid (n = 3) spermatogonial cells is entirely mitotic. Spermatogenesis begins within one hour after protonymphal feeding and continues through adult ecdysis in normally fed individuals. Nutritional deficit causes cessation of spermatogenic divisions in deutonymphs starved 23 days, but is rapidly rejuvenated upon feeding. No rejuvenation of division was observed in adult males given the opportunity to feed, thus adult males might not feed.
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  • 89
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    Journal of Morphology 148 (1976), S. 65-87 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In Brallchiobdella pentodonta Whitman meiosis begins in follicles containing 16 spermatogonia. In each follicle the spermatogonia are connected by cytoplasmic bridges to a central anuclear cytoplasmic mass or cytophorus. They develop synchronously. Synaptonemal complexes are present in the primary spermatocytes. Spermatids contain a large globoid paranuclear body consisting of an acrosomal granule and coiled tubules which evidently receive the contents of the acrosomal granule and are considered the acrosome carrier. The spermatids separate from the cytophorus only when differentiation is completed.The ripe spermatozoon is relatively long. It has anteriorly the coiled tubules, followed by the nucleus, the mitochondrial sphere and the distal centriole from which the flagellum originates, A coiled ribbon-like structure encloses the flagellum along its entire length while a manchette of microtubules surrounds all the other structures of the sperm.
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  • 90
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    Journal of Morphology 148 (1976), S. 89-135 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The muscles and bones of the pectoral fin of Serrasalmus nattereri, the piranha, resemble those of generalized, lower teleosts with specializations related to a body shape adapted for high-speed carnivory; the pectoral fins being highly mobile with strong ligaments to the rays. The presence of two occipital nerves appears primitive, while the emergence of the subclavian artery within the branchial cavity, as in Gasteropelecus sternicla, appears specialized. The muscles and bones of the latter fish, a fresh-water flying fish, are specialized for self-propelled, aerial flight in the fusion of the right and left girdles greatly expanded for insertions of complex appendicular (flight) muscles, and in the consolidation of the rays and radials into one functional unit moving vertically in flight though contraction of vertical, massive ventral flight muscles. The bony pectoral anatomy of Electrophorus electricus, the electric eel, is specialized in having a mobile joint between the primary girdle and the cleithrum, the former being suspended vertically from the cleithrum by ligaments. The proximal radials and rays are very numerous and vertically aligned. The cleithrum is shaped to accommodate the extensive sternohyoid and pharyngocleithral muscles. The sheet-like appendicular muscles extend beyond the special joint and control its movement. The deeper muscles do not cross this joint. The arterial system is specialized in lacking a deep brachial artery.
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  • 91
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976), S. 161-176 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Larvae of the stolidobranch ascidian Metandrocarpa taylori molt a thin sheath upon settling, then metamorphose and radiate a larval complement of vascular ampullae upon the substrate. These ampullae thereafter regress, “rest” in a reduced condition for several weeks, and then regrow into the oozooids definitive array of vascular ampullae in accompaniment to the development of the oozooidal vascular nest of test-vessels. Pallial buds emerge some four months after the larva settles; the oozooid has by then grown to a length of at least 2 mm and its vascular nest is surrounded by at least 16 vascular ampullae. Oozooids bud one to five buds (mean, 2.6) in a rather short period of blastogenic vigor, then persist in the colony. Late buds are frequently aborted. Buds appear anywhere around the basal margin of the oozooid, but more often on the left than the right and more often posteriorly than anteriorly. As other studies have observed with blastozooids, this study notes an integration of budding and the disposition of the elements of the test-vessel system of oozooids. Buds emerge oriented tangentially to the parental basal margin at the bud-site, then often rotate to point their anterior ends away from the parent. No larvae metamorphosed into oozooids with situs inuersus uiscerurn, but in this study two oozooids extruded blastozooids showing this anomaly; these blastozooids budded reversed zooids in turn, so that entire clonal lines showed the anomaly.
    Additional Material: 3 Ill.
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  • 92
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976), S. 255-264 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The modified midventral scales on Percina males probably function to induce tactile stimulation of the female during spawning. The midbelly row of modified scales presumably evolved as a result of increased selective advantage of larger and more strongly toothed scales on the midventer; primitive and intermediate conditions in the evolution of the modified scales as well as a distinctly modified row are extant, The morphology of the scales varies seasonally and ontogenetically. The scales are permanent rather than deciduous as described in the literature interspecific variation of the modified scales is pronounced intersubgenerically. less so intrasubgenerically.
    Additional Material: 3 Ill.
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  • 93
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976), S. 265-286 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Plethodontid salamanders capture prey by projecting the tongue from the mouth. An analysis of theoretical mechanics of the hyobranchial skeleton is used to formulate a working hypothesis of tongue movements. Predictions that the skeletal elements of the tongue are included in the projectile and that the hyobranchial skeleton is folded during projection are central to the analysis, When decapitated in a particular way, salamanders project the tongue, and it is not retracted. When these heads are fixed and sectioned, examination confirms the predictions, In turn, these observations are used to refine the working hypothesis and to generate a general model of tongue dynamics for plethodontids. Muscles performing the major roles of projection (subarcualis rectus I) and retraction (rectus cervicis profundus) are identified. The skeleton is folded passively along a morphological track having the form of a tractrix, Predictions concerning the shape of the track and the exact configuration of the folded skeleton are confirmed by study of sectioned material. The skeleton unfolds along the track during retraction and is spread into the resting state, The model developed herein will be used as a basis for predictions concerning selection patterns in the family and for analytical purposes in comparative and evolutionary studies.
    Additional Material: 13 Ill.
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  • 94
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976), S. 329-336 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scales on the hairs of pollinating bats spread out at an angle to the main hair shaft. In contrast, the hairs of most bats not associated with plants are relatively smooth. Both megachiropteran and microchiropteran flower-feeding bats show this divaricate scale structure which may aid in the collection of a heavy coating of pollen. Some of the pollen is transferred to subsequent flowers, but most is groomed from the fur and ingested as the only reliable nitrogen source for the bat.The tongues of nectar-feeding bats also show structural modifications which allow efficient uptake of the carbohydrate fraction of the diet.Structural specializations of the hairs and tongue are analogous to those seen in other nectar-feeding animals.
    Additional Material: 7 Ill.
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  • 95
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 73-103 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The general morphology of the gills is similar in larval (ammocoetes) and parasitic adult sea lampreys, Petromyzon marinus, despite different methods of ventilation necessitated by their feeding habits.The gill lamellae are supported by randomly-distributed pillar cells which enclose blood spaces and collagen columns. The distribution of these cells in lampreys is different from that of higher fishes and it may be inefficient for respiratory exchange. The presence of cytoplasmic microfilaments suggests that these cells have the ability to reduce the lamellar blood spaces through contraction. Marginal channels at the tips of the lamellae are lined only by endothelial cells.The thickness of the water-blood pathway in lampreys falls within the range described for higher fishes, with the most efficient gas exchange likely occurring at the lamellar tips where only a single layer of epithelial cells is present. The abrupt increase in height of the epithelium near the lamellar bases in adults, compared to the gradual transition in height along the lamellae in ammocoetes, is perhaps reflective of higher oxygen requirements during the parasitic stage. The consistent appearance of wide, lateral intercellular spaces within the respiratory epithelium of lampreys indicates possible involvement of these spaces in transport.Mucous secretion appears to be an important function of the superficial platelet cells in ammocoetes. “Mitochondria-rich” and “mitochondria-poor” superficial cells are observed in both ammocoetes and adults, with the mitochondria-rich cells more prevalent toward the lamellar bases. The possibility that at least some of these cells may be involved in absorption is discussed. Mitochondria-rich cells in the interlamellar region are morphologically different in ammocoetes and adults but all possess an abundance of smooth endoplasmic reticulum and hence resemble “chloride cells” of higher fishes. The similarity of these cells in the parasitic adult lamprey to chloride cells of marine fishes may reflect the potential of the adult lamprey to osmoregulate in salt water. A scarcity of these cells in ammocoetes and their resemblance to chloride cells in freshwater fishes may reflect the restriction of larval lampreys to a freshwater habitat.
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  • 96
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sexual dimorphism in the distribution of antennal sense organs is common among adults of the genus Periplaneta. In three out of the four strains of Periplaneta americana examined, adult males had more contact chemoreceptors than females. In the fourth strain of P. americana and in P. australasiae, P. brunnea, P. fuliginosa, and P. japonica, no statistically supportable sexual dimorphism of contact chemoreceptors was found. However, in all strains and species of Periplaneta examined, sexual dimorphism was found in the total number and/or density of olfactory sensilla. Male adults had nearly twice as many olfactory sensilla as female adults. These observations are consistent with the behavioral observation that males within the genus Periplaneta rely on the reception of an airborne pheromone for the initiation of courtship behavior. In P. americana, where sexual dimorphism was found in the contact chemoreceptors, contact stimuli release the full wing raising display and presentation in males during courtship.
    Additional Material: 8 Ill.
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  • 97
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 183-197 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The main excretory ducts (MED's) from the submandibular gland of adult cats were examined by electron microscopy. The ducts consisted of a pseudostratified epithelial lining surrounded by abundant connective tissue and numerous, small, longitudinally-oriented blood vessels. The taller epithelial cells were closely coherent, without the luminal clefts between adjacent cells that are characteristic of rat MED's. In the cat, these cells lacked basal membrane specialization, but showed considerable lateral interdigitation. Some microvilli were present on the apical surface. In a'few rare cells, the luminal surface bore cilia of typical appearance. The smaller, pyramidal basal cells had irregular basal surfaces that gave rise to one or more long cytoplasmic processes. The basal surface of the pyramidal cells was studded with hemidesmosomes. The cytoplasm contained abundant tonofilaments, which sometimes aggregated in prominent perinuclear bundles. Occasional goblet cells were present in the duct wall.MED's perfused either in situ or in a perfusion chamber with Locke's solution also were studied. Even after perfusion of 160 minutes duration, the ultrastructure of the ductal epithelium showed remarkably few alterations. The MED model system thus remains stable long enough to carry out physiological experiments which may produce ultrastructural alterations.
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  • 98
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 199-221 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The byssus attachment plaque and the tissues responsible for its formation were studied in M. califomianus by light microscopy and by transmission and scanning electron microscopy. It was shown that the plaque consists of at least three phases which ultrastructurally resemble three secretions considered to be collagen, mucoid material and polyphenol. The mucoid and polyphenol appear to mix as a colloidal suspension in which the latter is the continuous phase and forms the definitive bonding surface. Plaque collagen represents an extension of thread material into the cementing substance.Stimulated secretion within the ducts and distal depression of the mussel's foot shows a continuum of increasing heterogeneity from the inner toward the outer regions. This reflects the distribution of exocrine cell apices wherein exocytosis of polyphenol granules predominate deeply, mucous granules superficially and collagen granules in between.It is proposed that the morphology of the plaque conforms to theoretical physical-chemical requirements for adhesion under water.
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  • 99
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 265-277 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Oogenesis of the fresh-water triclad Dugesia dorotocephala has been studied by electron microscopical methods, with particular regard to the genesis and composition of the so-called “Balbiani body.” Its origin is clearly recognizable in young oocytes where the few mitochondria present seem to gather at the level of the perinuclear ooplasm. Here they surround dense masses of finely granular, fibrillar material probably coming from the nucleus. During the previtelloge ic period, mitochondria rapidly increase in number while the dense masses progressively dissolve.In the vitellogenic oocytes the Balbiani body shows its final configuration: it appears as a large area (up to 15-20 pm in diameter) consisting of innumerable densely packed mitochondria, some smooth vesicles and free ribosomes. This aggregate of cytoplasmic organelles remains unmodified in the mature oocytes.The function of the “Balbiani body” of D. dorotocephala is as yet unclear; it can only be asserted that it is not correlated with yolk production in which the endoplasmic reticulum and the Golgi complex are involved.
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  • 100
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 421-435 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Whole ovaries from 16-day fetal mice were cultured for 6 to 20 days and then transplanted to the kidneys of ovariectomized adult mice where they remained for one to four weeks. After three weeks in the host's kidneys, many follicles developed within the transplants and became vesiculated. Many of the oocytes within these follicles had formed the first metaphase spindle of meiosis and several had completed the first polar body. Host mice bearing transplants that contained vesiculated follicles showed uterine stimulation and keratinization of their vaginae. However, ovaries that had been in culture for more than ten days before transplantation showed a limited response to the gonadotropins and never matured sufficiently to stimulate the host's reproductive tract. No ovulations occurred in any of the transplants.
    Type of Medium: Electronic Resource
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