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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 11 (1970), S. 360-372 
    ISSN: 1432-1106
    Schlagwort(e): Brain slices ; Ultrastructure ; Synaptic potential ; Metabolism ; Olfactory cortex
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The fine structure and electrical activity were studied in thin brain sections prepared from the olfactory cortex of the guinea pig and incubated in vitro in standard and modified conditions. In the standard medium, the potential response was maintained with no marked changes for 4–5 hours and thereafter gradually decreased. The ultrastructure of the tissue was well preserved for the initial 2 hours of incubation. After incubation for 5 hours, many empty spaces were noted. Some dendritic stumps lost fine internal structure, but most of the synapses were apparently normal. Cyanide suppressed the potential response, and caused swelling of the nerve terminals and a decrease in the number of synaptic vesicles. The recovery of the response in the standard medium was not accompanied by a full restoration in the fine structure. If slices were incubated in the absence of glucose and oxygen, with cyanide in glucose-free medium, or at a low temperature, the potential response was irreversibly depressed. In these slices, numerous wide spaces of low electron density were noted which were concluded to have been derived, at least partly, from the swollen dendrites.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 15 (1970), S. 34-44 
    ISSN: 1432-0533
    Schlagwort(e): Ultrastructure ; Degeneration ; Necrosis of Muscle ; Dystrophy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die ultrastrukturellen und histochemischen Merkmale von drei Muskelfaserveränderungen — Faserverzweigung, große Fasern und nekrotische Fasern — wurden an 129 dystrophischen Bar Harbor-Mäusen untersucht. Die Pathogenese dieser Veränderungen, die als Schädigungsfolgen aufgefaßt werden, wird diskutiert. Obwohl diese Veränderungen nicht als spezifisch angesehen werden, sind sie doch charackteristisch für die Histopathologie der Muskeldystrophie, so daß das Verständnis des Mechanismus, der diese abnormen Muskelfasern hervorbringt, zur Kenntnis des dystrophischen Prozesses beitragen dürfte.
    Notizen: Summary Ultrastructural and histochemical features of three muscle fiber changes — branched fibers, large fibers and necrotic fibers — have been studied in Bar Harbor strain 129 dystrophic mice. The pathogenesis of these changes, which are considered to be responses to injury, have been discussed. Although these changes are not regarded as specific, they are characteristic of the histopathology of muscular dystrophy, so that an understanding of the mechanisms which produce these abnormal muscle fibers should contribute to the knowledge of the dystrophic process.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 109 (1970), S. 356-379 
    ISSN: 1432-0878
    Schlagwort(e): Gingivo-Dental junction ; Human ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé L'étude ultrastructurale de la jonction gingivo-dentaire humaine a permis de montrer que les membranes cytoplasmiques des cellules épithéliales superficielles, revêtues de nombreux hémi-desmosomes, sont en rapport avec les cristaux d'apatite de l'émail par l'intermédiaire d'un espace intercellulaire, de 400 à 1200 Å d'épaisseur, rempli d'un matériel finement granulaire, soit directement soit par interposition d'une cuticule discontinue, d'épaisseur variable, qui est appliquée à la surface de l'émail uniquement sur des dents, ayant effectué leur éruption. Cette cuticule, dont l'origine salivaire peut être exclue, subit une apposition de la surface de l'émail vers la périphérie. L'attache épithéliale n'est pas kératinisée, mais des faisceaux de tonofibrilles sont visibles dans les cellules. Une certaine tendance à la kératinisation a été parfois notée au niveau du sillon gingivo-dentaire. De nombreux polynucléaires éosinophiles et neutrophiles et des lymphocytes migrent à travers la jonction et le sillon gingivo-dentaires cliniquement normaux. Un élargissement des espaces intercellulaires, des ruptures de la membrane basale et des desmosomes, une accumulation parfois importante de glycogène, des noyaux polylobés et des oedèmes intracellulaires y ont également été notés. Enfin une rupture en ≪atimbre poste≫ entre les cellules épithéliales de la jonction, ainsi qu'une rupture entre l'émail et les cellules épithéliales superficielles contribuent à l'approfondissement du sillon gingivo-dentaire.
    Notizen: Summary The ultrastructural investigation of the human gingivo-dental junction shows that the plasmalemmata of the superficial epithelial cells, coated by numerous hemi-desmosomes, are related to the enamel apatite crystals through a finely granular intercellular space, 400 to 1200 Å in thickness, either directly or through a discontinuous dense cuticle, of irregular thickness, which is attached to the enamel surface of erupted teeth. This cuticle, of none salivary origin, is deposited from the enamel surface to the outside. The epithelial junction is not keratinized, but numerous tonofibrils bundles occur in the cells. A certain tendency toward keratinization was sometimes observed in the crevicular epithelium. Numerous eosinophilic and neutrophilic polymorphonuclear leukocytes, and lymphocytes migrate through the clinically normal crevicular and junctionnal epithelium. Intercellular space dilatations, basement membrane and desmosomes ruptures, important intracellular accumulations of glycogen, multilobulated nuclei and intracellular edemas are also sometimes observed. A serrated rupture between epithelial cells of the junction as well as a rupture between enamel and the most superficial epithelial cells contributes to the deepening of the gingival sulcus.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 111 (1970), S. 209-227 
    ISSN: 1432-0878
    Schlagwort(e): Isopod hindgut ; Histology ; Histochemistry ; Ultrastructure ; Osmo-regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The tubular hindgut of the intertidal herbivorous isopod, Dynamene bidentata, consists of a long dorso-ventrally flattened anterior region, surrounded by a network of muscles, and a short muscular sphincter which grades into a pair of anal flaps. The monolayer of epithelial cells forming the wall of the hindgut appears to take no part in the production of digestive enzymes, food absorption, or glycogen and lipid storage. One function of the hindgut is to propel undigested food material, enclosed within a peritrophic membrane, to the sphincter and anal flaps where faecal pellets are formed and ejected. At the fine structural level lateral plasma membranes, often partially obliterated by microtubules, are visible. The basal plasma membrane of a typical epithelial cell is deeply infolded, associated with mitochondria, and pinocytotic. The apical plasma membrane is irregularly folded, engaged in pinocytosis, and often encloses subcuticular spaces containing an acid mucopolysaccharide substance. An intima, composed of a thin double-layered epicuticle, and a thick acid mucopolysaccharide-positive endocuticle, overlies the cells. The endocuticle may selectively bind substances to the apical plasma membrane before they are engulfed by pinocytosis. The cells resemble those of osmoregulatory organs and may help counterbalance changes in the haemolymph concentration resulting from the intertidal existence of this isopod.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 111 (1970), S. 293-315 
    ISSN: 1432-0878
    Schlagwort(e): Herring bodies ; Ultrastructure ; Degeneration ; Regeneration ; Neurosecretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The Herring bodies in the posterior lobe of the bovine hypophysis are very large (2–600 μ) and can be classified into three types. The type I Herring body contains an accumulation of neurosecretory granules. These Herring bodies are very scarce and should not be confused with the numerous, but small, axonal swellings which also contain neurosecretory granules. The type II Herring body is characterized by the presence of a varying number of normal, moderately electron dense and “empty” vesicles, autophagic vacuoles, multilamellate bodies and occasional mitochondria. These Herring bodies are frequently observed. The type III Herring body is typified by the presence of dense vesicles connected to tubular formations which contain material of variable electron density, of filaments, and of long slender and very numerous mitochondria. The presence of multilamellate bodies and autophagic vacuoles suggests that the type II Herring body is in a degenerating phase. This concept is further substantiated by the similarity between this type of Herring body and transected neurosecretory axons in which degeneration is occurring. A similar comparison suggests that the type III Herring body is undergoing a regenerative process. Our current concept of the structure and function of Herring bodies is revised in the discussion.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    ISSN: 1432-0878
    Schlagwort(e): Corpora cardiaca ; Insects ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé L'étude infrastructurale des corpora cardiaca de Locusta révèle l'existence de 3 types de fibres neurosécrétrices (portion neurohémale) et d'un seul type de cellules glandulaires (portion endocrine intrinsèque). Elle permet également d'envisager les modalités du rejet des sécrétions exogènes et endogènes.
    Notizen: Summary An ultrastructural study of the corpora cardiaca of Locusta migratoria migratorioides shows three neurosecretory fiber types in the neurohaemal part of these organs; only one cellular type constitutes the intrinsic glandular part of the corpora cardiaca. This study also shows sites of release of stored extrinsic neurosecretory material and of products elaborated by intrinsic glandular cells of the corpora cardiaca.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    ISSN: 1432-0878
    Schlagwort(e): Neurosecretory Pathways ; Insects ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé L'étude infrastructurale des nerfs cardiaques afférents et des nerfs allato-cardiaques qui entrent dans la constitution du système neurosécréteur rétrocérébral de Locusta migratoria migratorioides (R. et F.) révèle l'existence des trois types de fibres neurosécrétrices définis dans les corpora cardiaca. Une quatrième catégorie de fibres caractérisées par la présence de vésicules claires existe dans les nerfs allato-cardiaques et dans les corpora allata. L'origine des fibres et l'évolution des grains de neurosécrétion au cours de leur transit sont envisagées.
    Notizen: Summary An ultrastructural study of the nervi corporis cardiaci and nervi corporis allati, which are part of the retrocerebral neurosecretory system of Locusta migratoria migratorioides, reveals the existence of three neurosecretory fiber types. A fourth neurosecretory fibertype with electron lucent vesicles is also present in the nervi corporis allati and in the corpora allata. The fibers are characterized by differences in the size and electron opacity of the neurosecretory granules. The origin of the various neurosecretory fiber types and the evolution of the neurosecretory granules are discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 105 (1970), S. 1-32 
    ISSN: 1432-0878
    Schlagwort(e): Median eminence ; Rat ; Deafferentation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary This report concerns a light and electron microscopic investigation of the median eminence and dorsal infundibular stem of the rat following surgical isolation (deafferentation). Using a modification of the Halász technique, the basal hypothalamus, including the arcuate nucleus and median eminence were surgically isolated from surrounding structures. Special attention was directed to the contact (external) zone of the median eminence and rostral infundibulum where tuberohypophyseal axons as well as ependymal cell processes abut upon the abluminal basement membrane of the portal perivascular space. The results of this study to date suggest that 9, 20, and 40 days following surgical isolation, there is a distinct increase in the population of tuberohypophyseal dense core vesicles. It is suggested that deafferentation abolishes inhibitory and excitatory input that serves to modify the cellular dynamics of tuberohypophyseal neurosecretory elements. Comments are also made on the presence of cistern-like structures in the lateral median eminence; the presence of vesicle-like inclusions in terminal ependymal processes is discussed in relationship to the role that ependyma may play in linking the third ventricle with the adenohypophysis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    ISSN: 1432-0878
    Schlagwort(e): Hypothalamo-hypophysial tract ; Rana pipiens ; Transection-hormonal content ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Several types of neurosecretory fibers were observed in the normal infundibulum of the frog. After transection of the median eminence, these neurosecretory fibers of the proximal stump reacted asynchronously, but followed approximately the same pattern: a “passive accumulation” of granules observed early after the transection was followed by an “active axonal reaction” with the appearance of numerous tubular formations which are thought to be related to the Golgi apparatus. They filled the axon almost completely, and then became dilated and filled with an electron dense material. Subsequently these dilatations pinched off and gave origin to new neurosecretory granules. These locally packed granules plus others which were probably formed in more proximal parts of the axon, and the perikaryon and then transported distally, accumulated in the proximal axonal stumps and started to fill the fibers retrogradely. There was a parallelism between the increase of tubular formations and neurosecretory granules larger then 1,500 Å in diameter, on one side, and the vasopressor activity of the proximal stump, on the other. The latter increased at an approximate rate of 1 mU/stump/day. The regeneration of the fibers of the hypothalamo-median eminence system is suggested by the presence in the proximal stump of fibers filled with granules smaller than 1,000 Å in diameter (normally seen in the median eminence) and the fact that 40% of the vasopressor activity of the extracts was not abolished by the thioglycollate treatment, which could be due to the presence of vasopressor amines other than adrenaline. The appearance towards the end of the observation period of a few “nerve endings” of several types contacting the perivascular basement membrane of vessels of the proximal stump would indicate that the neural lobe and median eminence functions were being reestablished, at least partially.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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