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  • ZIB Katalog
  • Artikel: DFG Deutsche Nationallizenzen  (35)
  • Opus-Repositorium ZIB
  • 1975-1979  (35)
  • 1900-1904
  • 1890-1899
  • 1830-1839
  • Electron Microscopy
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  • ZIB Katalog
  • Artikel: DFG Deutsche Nationallizenzen  (35)
  • Opus-Repositorium ZIB
Materialart
Erscheinungszeitraum
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 384 (1979), S. 159-172 
    ISSN: 1432-2307
    Schlagwort(e): Myxoid liposarcoma ; Histogenesis ; Electron Microscopy ; Hibernoma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ten myxoid liposarcomas (ML) were studied ultrastructurally in an attempt to determine the histogenesis of this neoplasm and structural associations which might contribute to their relatively benign clinical behavior. The findings were compared with normal and neoplastic adipose tissue. Three cell types were observed, i.e., “primitive” mesenchymal cells, intermediate cell types, and lipoblasts at various stages of development. The principle differences between the lipoblastic elements were the number and the size of intracytoplasmic fat vacuoles, the development of basement membrane-like material, micropinocytotic vesicles along the plasma membrane and the quantity and pleomorphism of mitochondria. The tumor vasculature was complex but consistently demonstrated a multilayered basal lamina. This finding has been described in neoplasms associated with a relatively good prognosis. This study demonstrates that the better differentiated lipoblasts in ML share some features with normal brown fetal fat and hibernoma. It is, thus, suggested that ML may be derived from brown adipose tissue.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 377 (1978), S. 145-155 
    ISSN: 1432-2307
    Schlagwort(e): Aggressive Fibromatosis ; Myofibroblast ; Immunperoxidase Method ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Zwei FÄlle von aggressiver Fibromatose der Schilddrüsenregion werden mit histologischen, immunhistochemischen und elektronenmikroskopischen Methoden untersucht. Mit Hilfe von menschlichem Serum gegen glatte Muskulatur können kontraktile Zellen in sÄmtlichen PrÄparaten, vornehmlich aber in den Randbezirken der Wucherung nachgewiesen werden. Elektronenoptisch werden alle diese Zellen als Myofibroblasten identifiziert. Die zentralen Bezirke der Wucherung zeigen hyalin verdickte und gequollene Kollagenfaserbündel mit nur wenigen zellulÄren Elementen. Somit wird der Myofibroblast als der für die Wucherung charakteristische Zelltyp erkannt. Die sich daraus für Pathogenese und Histogenese ergebenden Schlüsse werden diskutiert.
    Notizen: Summary Two cases of aggressive fibromatosis of the thyroid gland region were studied by histological, immunhistological and electron-microscopic methods. Contractile cells can be found in all tissue preparations using human serum containing antibodies to smooth muscle, especially in the periphery of the tumor. These cells have the characteristics of myofibroblasts by electron microscopy. The central areas of the tumor are composed of hyalin thickened bundles of collagen fibres with few cellular elements. The myofibroblast is thus considered to be the characteristic cell type of the tumor, and the pathogenesis and histogenesis of the lesion are discussed.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 378 (1978), S. 143-151 
    ISSN: 1432-2307
    Schlagwort(e): Neurinoma ; Schwannian Origin ; Neurinoma Cells ; Cytoplasmic Processes ; Peculiar Myelin Sheaths ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In benign tumours of the nerve sheath, the neurinoma clearly originates from the Schwann's cell. This can be said, because there are neurinoma cells with the typical tendency to cytoplasmic processes out of which peculiar myelin sheaths are built; these peculiar myelin sheaths wrap themselves around parts of their own neurinoma cell.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 379 (1978), S. 335-349 
    ISSN: 1432-2307
    Schlagwort(e): Thymus ; Thymoma ; Lymphocyte-epithelial Interaction ; “Emperipolesis” ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of eleven thymomas with lymphocytic predominance, one “epitheloid” cell thymoma and two normal human thymuses is described with special reference to “Emperipolesis”. All patients have had myasthenia gravis. The normal human thymus consists of three parts: outer cortex, inner cortex, and medulla. The outer cortex contains mainly lymphoblasts and Metcalf's macrophages within the so-called “Clark-packet's”. The inner cortex consists mainly lymphocytes and interdigitating reticulum cells, and the medulla of epithelial cells, lymphocytes and Hassall's corpuscles. In all cases of lympho-epithelial thymoma and in normal human thymuses there are enormous interdigitations between epithelial (tumor) cells, lymphocytes and macrophages. The “epitheloid” cell thymomas also show findings which suggest an epithelial cell interaction. We have not found intact lymphocytes inside the cytoplasm of normal and/or tumor epithelial cells, macrophages or interdigitating reticulum cells. The intracellular existence of intact lymphocytes has been termed “Emperipolesis” by Humble, Jayne, and Pulvertaft, meaning “internal wandering”. These investigations indicate that “Emperipolesis” is not an adequate term for cellular interaction in normal human thymuses and thymomas. A false impression of intraepithelial location of thymic lymphocytes is created by two-dimensional sections of complex thymic structure. These ultrastructural studies revealed damage to lymphocytes only in macrophages with lymphocytolysis within these cells and accumulation of numerous heterophagic vacuoles containing fragments of lymphocytic debris within them.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 380 (1978), S. 49-57 
    ISSN: 1432-2307
    Schlagwort(e): Granular cell tumor ; Schwannian Origin ; Phagocytozing Schwann cells ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In granular cell tumors, the granule-containing tumor cells and their processes form rounded complexes surrounded by a common bounding membrane. In the tumor, these complexes are closely related to the peripheral nerves and are seen in the perineurium and in the endoneurium. In addition, there are mixed complexes composed both of Schwann cells and granular tumor cells: the two types of cells are in close contact with each other and are also surrounded by a common bounding membrane. Furthermore, there one contacts between granular tumor cells and axons. These observations strongly suggest the existence of a relationship between Schwann cells and the cells of granular cell tumors. A comparison between the granular tumor cells and the phagocytic forms of Schwann cells reveals striking similarities: the granular cell tumor complexes are comparable with the Büngner bands of phagocytozing Schwann cells. A relationship between granular cell tumors and the phagocytozing form of Schwann cells is therefore assumed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    ISSN: 1432-2307
    Schlagwort(e): Rapidly occuring atheroma ; Adrenalin ; Hypercholesterolemia ; Histoenzymology ; Electron Microscopy ; Vascular repair ; Experimental atheroma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An initial parenteral injection of adrenalin-thyroxin (1 injection daily for 5 days) followed by a high lipid diet induces an unusual, rapidly occuring atheroma in the rabbit aorta. Previous ultrastructural and histoenzymologic studies of the same model have shown obvious intimal and medial changes, apparently due to the hormonal treatment alone. Repair occurs quickly. The mechanism of atherogenesis is uncertain. The present study reports the occurence of obvious atherosclerosis at later stages in this model, when studied by the same methods. The changes are compared with those induced by hormonal treatment alone, allowing some insight into the additional effects of adrenalin and cholesterol on rabbit aorta: — two sets of 6 experimental animals were killed after one month. In the first group, receiving hormonal treatment alone, the vascular wall is not completely repaired and a change in the histochemical perfusion gradient (elevated level of hydrolase activities of the outer layers of the vessel) remains. In the second group, receiving hormonal treatment and the lipid diet, atheromatous plaques containing lipid containing cells appear at intimal level. These cells develop by migration of myocytes from the medial layer. Cholesterol seems to be the main factor inducing the smooth muscle cell migration and lipid deposition and its proliferative effect is increased by the elevated vascular permeability. — after adrenalin-thyroxin, 6 animals received the lipid diet for one month and were sacrificed after a further month. Atheromatous plaques were still present and contained higher lipid levels. Medial scarring may disturb the parietal gradient and increase the intimal lipid accumulation found.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 23 (1977), S. 45-51 
    ISSN: 1432-0827
    Schlagwort(e): Electron Microscopy ; Cytochemistry ; Glycogen ; Chondrogenesis ; Chick Embryo
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The distribution and localization of glycogen particles in mesenchymal cells, chondroblasts and in young, hypertrophic and degenerating chondrocytes of the tibiotarsal anlage of developing chick embryos were examined ultrastructurally using the periodic acidthiocarbohydrazide-silver proteinate. The distribution of glycogen particles increased with the degree of differentiation and maturation of the chondrogenic cells. Mesenchymal cells showed minimal content of glycogen particles which gradually increased in the chondroblasts. The young chondrocytes further showed increased glycogen particle content compared to chondroblasts. This content reached a maximum level in hypertrophic chondrocytes. This level subsided in degenerating chondrocytes which showed a much reduced distribution of glycogen particles compared to hypertrophic chondrocytes. The morphological nature of glycogen particles depended on the degreee of cellular differentiation. Both mesenchymal cells and chondroblasts contained single particles, while the glycogen particles of chondrocytes aggregated and formed a series of interconnected particles.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 179 (1977), S. 197-209 
    ISSN: 1432-0878
    Schlagwort(e): Interrenal gland ; Hepatectomy ; Amphibia ; Electron Microscopy ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Partial hepatectomy was carried out on Xenopus laevis to investigate its influence on the endocrine system. In addition to other endocrine effects, a marked hypertrophy and stimulation of the interrenal gland was observed. Activated cells contain mitochondria with extended and irregularly coiled tubules embedded in a low electron dense matrix. Hepatectomy induces two phases of proliferation [3 and 35 days postoperative (p.o.)]. After 106 days p.o. giant mitochondria possessing narrow and closely packed, parallel tubules surrounded by an electron dense matrix indicate a phase of inactivation. The smooth endoplasmic reticulum and the Golgi apparatus proliferate after hepatectomy. During activation the high lipid content seen in controls is decreased significantly.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 371 (1976), S. 295-303 
    ISSN: 1432-2307
    Schlagwort(e): Ecchordosis physaliphora ; Embryonic chick notochord ; Electron Microscopy ; Chordoma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ecchordosis physaliphora, a small gelatinous mass attached to the midline of the clivus, is characterized ultrastructurally by glycogen-laden intracytoplasmic vacuoles, focally distended endoplasmic reticulum and perinuclear cisterns with cytoplasmic invaginations, large clusters of granular endoplasmic reticulum interdigitating with mitochondria, and an abundant extracellular space. These morphologic features are also present in the 9-day embryonal chick notochord and the human chordoma and serve to reaffirm the derivation of the ecchordosis and chordoma from notochordal rests.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 365 (1975), S. 327-336 
    ISSN: 1432-2307
    Schlagwort(e): Crohn's Disease ; Electron Microscopy ; Granuloma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The epithelioid cells forming the granulomata of Crohn's disease show striking vacuolation from the coalescing of pinocytotic vesicles with double membrane-bound bodies and their subsequent fusion with lysosomal dense bodies. The fine detail of the granulomata in each individual is uniform but varies from case to case in such a way as to suggest an episodic stimulation of pinocytosis and vacuole formation. The production of such granulomata with these cyclical appearances is consistent with an intermittent stimulus by exogenous antigen or antigen antibody complexes arriving in the diet.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 367 (1975), S. 93-112 
    ISSN: 1432-2307
    Schlagwort(e): Spermatids ; Spermatozoa ; Spermatogenesis ; Malformed Germ Cells ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Fehlgebildete Spermatiden und Spermatozoen in den Hoden, Nebenhoden und Ejaculaten von 29 gesunden Männern und von 171 Patienten mit verschiedenen andrologischen Erkrankungen wurden elektronenmikroskopisch untersucht. Die folgenden Mißbildungstypen lassen sich beschreiben: 1. Akrosomfehlbildungen in Kontakt zum Spermatidenkern: bläschenförmige Einschlüsse in der Akrosomblase, asymmetrische Verdickungen der Akrosomkappe, Einfaltungen der akrosomalen Lamina in den Spermatidenkern, teilweise Abhebung des Akrosoms vom Kern, apikale knopfartige Verdickungen des Akrosoms. 2. Akrosomfehlbildungen unabhängig vom Spermatidenkern: das akrosomale Material ist enthalten in kleinen Bläschen, ringförmigen Strukturen, in rundlichen oder schalenartigen Formen. Der Kern solcher Spermatiden hat kein Akrosom. 3. Fehlbildungen des Kerns: Einschlüsse von Bläschen oder Membranen, ausgedehnte Membranbildungen, sehr große Kernvacuolen, fehlende Kondensation des Karyoplasma. 4. Mehrkernige Spermatiden: zwei oder mehr Kerne in einem Perikaryon sind durch ein Akrosom verbunden. 5. Doppelte Akrosomanlagen. 6. Fehlbildungen des Schwanzes: Zerstörung des Axonema, Unterdrückung oder Überzahl von Tubuli und Fasern, doppelte axiale Filamentenbündel, Destruktion der Halsregion, Fehlen der Mitochondrienscheide, Auftreibung der Faserscheide. Mißgebildete Keimzellen treten in unterschiedlichen Prozentsätzen sowohl bei gesunden Männern als auch bei infertilen Patienten auf. Damit ist das Vorkommen fehlgebildeter Keimzellen nicht unbedingt ein Hinweis auf eine bestehende Infertilität. Nur bei bestimmten Mißbildungstypen, wie den rundköpfigen Spermatozoen, ist — wenn alle Spermatozoen im Ejaculat den gleichen Defekt aufweisen — mit Infertilität zu rechnen.
    Notizen: Summary Malformed spermatids and spermatozoa in the testes, epididymes, and ejaculates of 29 apparently healthy men and in 171 patients suffering from different andrological diseases were investigated with the electron microscope. The following types of malformations are described: 1) Malformations of the acrosome in contact with the nucleus of the spermatid: Vesicular inclusions in the acrosome vesicle, asymmetric thickenings of the acrosome cap, enfolding of the acrosomal lamina into the spermatid's nucleus, partial separation of the acrosome from the nucleus, apical knob-like thickenings of the acrosome. 2) Malformations of the acrosome independent from the spermatid's nucleus: the acrosomal material is contained in small vesicles, large vacuoles, in ring-like structures, in globular or shell-like laminar structures. The nucleus of such spermatids lacks an acrosome. 3) Malformations of the nucleus: inclusions of vesicles or membranes, excessive packages of membranes, gigantic nuclear vacuoles, lack of condensation of the caryoplasm. 4) Multinucleate spermatids: two or more nuclei within the pericaryon of one spermatid are joined by an acrosome. 5) Duplicate acrosome anlagen. 6) Malformations of the tail: disorganization of the axonema, a lack or excessive numbers of tubules and fibres, doublets of the axial filaments, destruction of the neck region, a lack of the mitochondrial sheath, and enlargement of the fibrous sheath. Malformed germ cells were observed to occur in varying amounts both in apparently healthy men and in those who were apparently infertile. This indicates that germ cell malformations are no absolute indicator of male infertility. However, certain distinct types of malformations (such as round-headed spermatozoa) are definitely associated with infertility, but only if all spermatozoa in the ejaculate of a patient have the same defect.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 366 (1975), S. 353-356 
    ISSN: 1432-2307
    Schlagwort(e): Sturge-Weber Disease ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of calcareous deposits in a case of Sturge-Weber disease is described. Concrements were found mainly extracellularly, outside of blood vessels, but there were some also within the vessel walls. The laminated concrements are built up of fine filaments, similar to those seen in the Fahr's disease. Needle-like cristals (calcium apatit) were observed within the concrements. Increased permeability of the altered vessel walls may be responsible for these alterations.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 367 (1975), S. 181-194 
    ISSN: 1432-2307
    Schlagwort(e): Malignant Hyperthermia ; Latent Myopathy ; Enzyme Histochemistry ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die maligne Hyperthermie ist charakterisiert durch einen rapiden Anstieg der Körpertemperatur, Muskelkontraktionen und zunehmende Hypoxie. Sie ist eine moderne Narkosekomplikation mit einem sehr hohen Letalitätsrisiko von über 60%. Da über die morphologischen Veränderungen bei maligner Hyperthermie sehr wenig bekannt ist, wurden an Muskelbiopsien von 3 Patienten mit maligner Hyperthermie und einem sog. Risikopatienten histologische, histochemische und elektronenmikroskopische Untersuchungen durchgeführt. Histologisch zeigten sich akute Muskelfasernekrosen, außerdem wurden Hinweise für eine latente Myopathie erhoben. Histochemisch ergab sich, daß beide Muskelfasertypen I und II befallen waren. Mit der Phosphorylase-Reaktion konnten auch bei Fasern, die bei üblicher histologischer Bearbeitung unauffällig waren, pathologische Veränderungen nachgewiesen werden. Elektronenmikroskopisch konnten neben einer akuten Rhabdomyolyse eine Erweiterung der Zisternen des sarkoplasmatischen Beticulums und eine eigentümliche Einrollung bzw. Wucherung des Sarkolemms beobachtet werden. Die Befunde unterstützen die pathogenetische Vorstellung anderer Autoren, daß dieses Syndrom, das durch Inhalationsnarcotica und Muskelrelaxantien (Halothan bzw. Succinylcholin) ausgelöst wird, auf der Grundlage eines Defektes caloiumspeichernder Membranen des sarkoplasmatischen Reticulums beruht. Wegen des familiären Auftretens dieser Komplikation sollte angestrebt werden, klinische, laborchemische und morphologische Untersuchungen auch bei den Verwandten solcher Patienten zum Ausschluß einer derartigen latenten Myopathie durchzuführen.
    Notizen: Summary Malignant hyperthermia is a rare but severe complication of modern anesthesia, induced by halothane and succinylcholine. The syndrome is characterized by a rapid sustained and extreme rise in body temperature associated with muscular rigidity, tachycardia, tachypnoea and cyanosis. The lethality is about 60%. The present paper describes the histological, histochemical and electron microscopical findings performed on muscle biopsies of 3 patients with malignant hyperthermia (1 patient died) and a so called risk patient. In all patients morphological findings consistent with a pre-existent myopathy were found. Histologioally there were acute necrotic muscular fibers as well as in types I and II, variations in the fiber diameter and centralization of the nuclei. In two cases even fibers that had a normal aspect in HE slides, showed a pathologic pattern after phosphorylase reaction. In addition to acute rhabdomyolysis, electron-microscopic investigations revealed cystic expansion of the cisterns of the sarcoplasmic reticulum with a peculiar proliferation of the sarcolemma. In a degenerating mitochondrium, a crystalline inclusion was identified. These findings support the pathogenetic concept of Britt and coworkers of a functional defect in the calcium release or binding mechanism of sareoplasmic reticulum. Since it is known that malignant hyperthermia has a familial predilection, it seems very important that clinical, biochemical, and morphological investigations be performed such as CPK estimations and muscular biopsies not only of the patients but also of the relatives in order to rule out this type of latent myopathy.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 32 (1975), S. 199-207 
    ISSN: 1432-0533
    Schlagwort(e): Marchi Reaction ; Secondary Demyelination ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A secondary demyelination process was brought about in the optic tract by unilateral enucleation of 10 adult rats which were sacrificed at 8, 15, 20, 30 and 45 days respectively, after the intervention. The Marchi reaction, which is identifiable by the presence of granular bodies, is positive at all stages, but tends to lessen towards the 45th day. The granular bodies are inside the disintegrating myelin sheath, and gradually fill the space made available by the degenerate axoplasm. The granular bodies are at first bulky and compact before breaking up and disappearing. The remains of the myelin sheath are then resorbed. Satellite cells occur from the 15th day onwards. The interest of the Marchi reaction for the tracing of nervous pathways is confirmed by these findings.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 31 (1975), S. 207-217 
    ISSN: 1432-0533
    Schlagwort(e): Congenital Myopathy ; Reducing Body Myopathy ; Histochemistry ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A muscle biopsy of a boy of 14 years presenting clinically a benign congenital myopathy showed granular intrasarcoplasmic bodies exhibiting reducing activity. They resemble the bodies described by Brooke and Neville in muscle of two children with severe congenital myopathy which they referred to as “reducing body myopathy”. If the reducing bodies are the characteristic morphological feature peculiar to this newly recognized congenital myopathy, the case reported here would be therefore a benign form of reducing body myopathy. The origin and nature of the granular material forming the bodies is doubtful. The close relationship between this material and the myofilaments may suggest that the granules arise from some myofibrillary component.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 31 (1975), S. 273-279 
    ISSN: 1432-0533
    Schlagwort(e): Intracisternal Virus ; Helper Virus ; Virus Persistence ; Electron Microscopy ; Tubuloreticular Structures
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A previously healthy middle aged man died following a 6 month illness which presented with middle ear symptoms, apparently resolved, and then 2 months later manifested as encephalitis. The illness was characterized initially by depression and intellectual deterioration. No family member or working associate was affected. The clinical diagnosis of viral encephalitis was confirmed by brain biopsy but no virus was isolated in the laboratory. Numerous intracisternal toroidal virus-like particles were demonstrated by electron microscopy in the perikarya and dendrites but not in glia. The particles resemble, but are not identical to, the oncornaviruses associated with spontaneous and induced murine neoplasms. The resemblance of these structures to the intracisternal toroidal type “A” virus of murine leukemia is noted and other possible causes for this atypical meningoencephalitis are discussed.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 31 (1975), S. 129-135 
    ISSN: 1432-0533
    Schlagwort(e): Electron Microscopy ; Cerebellar Hemangioblastoma ; Cytoplasmic Tubular Inclusions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The present study reports unusual, long, tubular, rod-shaped cytoplasmic inclusions found in the stromal cells of a cerebellar hemangioblastoma, associated with von Hippel-Lindau syndrome. These inclusions have two layers of circular, laminated filaments, and longitudinally arranged filaments; and appear similar to the so-called “Hirano bodies”, which have been previously found in normal and various pathologic conditions of the brain tissue, skeletal muscle cells in myopathy, and interstitial cells of the testis. A review of previous ultrastructural studies of cerebellar hemangioblastoma shows several different types of cytoplasmic inclusions, but none are found to be identical to the present report.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 31 (1975), S. 229-242 
    ISSN: 1432-0533
    Schlagwort(e): Capillary ; Maturation ; Human ; Cerebral Development ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructural characteristics of the cerebellum and olfactory bulb capillaries were studied in 12 human specimen measuring 25–200 mm. Type I capillaries, whose lumina were wider than 8 μ contained no pores or fenestrations. The basement membrane was sometimes discontinuous. In that case, junctions without quintuple-layered zones could be observed. Such capillaries may correspond to primary vessels in which the sinusoid character has disappeared. Elsewhere, the basement membrane was continuous and the interendothelial junctions always contained quintuple-layered zones. Type II capillaries, whose lumina measured between 2 and 8 μ had basement membranes that were either discontinuous or continuous. They were identical to the immature capillaries described previously in numerous species including man. Type III capillaries, rarely observed, were characterized by the presence of several endothelial cells with abundant cytoplasm, which limited the lumina from 0.5–3 μ in diameters. They had continuous basement membranes. Type IV and V capillaries has small or non-patent lumina. The basement membrane was absent or rudimentary. These capillaries appeared to correspond to simple and complex endothelial sprouts. In Types II, III, V and most Type IV capillaries, the interendothelial junctions contained quintuple-layered zones. No mature capillaries were observed. The hypothetical pathways of development of cerebral capillaries and the degree of permeability of immature interendothelial junctions are discussed. The long duration of maturation in man probably accounts for the diversity of capillary formations observed as compared with animals. The co-existence over a long period of time of several capillary types with probably varying permeability may play a significant role in the maturation of the blood-brain barrier.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 31 (1975), S. 305-313 
    ISSN: 1432-0533
    Schlagwort(e): Fahr's Disease ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In a woman, aged 52, who had impaired phosphate excretion and low serum calcium levels, abundant calcium deposits (Pseudokalk) were found between the basement membranes of blood vessels in the regions of corpus striatum and nucleus dentatus as well as in the subcortical white matter and centrum semiovale. Calcium deposits were found also outside blood vessels but always in teh vicinity of the basement membrane. These can be phagocytozed by makrophages or astrocytes. Calcium deposits have a characteristic ultrastructure. They are built up of 140–400 Å electron lucent filaments (acid mucopolysaccharids?) within which electron dark segments built up of 40–80 Å units (calcium deposits?) are found. The concentric rings of calcified deposits are of reflection of differing density of aggregation of dark filaments. The growth of the deposits takes place by additional precipitation. In the development of calcification of the cerebral blood vessels in Fahr's disease, the role of high serum phosphate levels, the increased permeability and dysfunction of mesenchymal cells of the vessel walls are discussed.
    Materialart: Digitale Medien
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  • 20
    ISSN: 1432-1912
    Schlagwort(e): d-Tubocurarine ; Subcellular Distribution ; Lysosomes ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary After i.v. injection in the rat, d-tubocurarine is taken up and concentrated by the liver. A method is developed for the visualisation of d-tubocurarine inside the liver cell by electron microscopy. Glutaraldehyde fixed liver blocks were immersed in an ammonium molybdate solution; d-tubocurarine was precipitated at sites of high concentration by molybdate, to form an insoluble d-tubocurarine-molybdate complex. This precipitate was found predominantly at the surface of lysosome-like particles, but also inside these organelles. In subcellular fractionation experiments, d-tubocurarine was found with a high relative specific “activity” in the lysosomal fraction, lending support to a lysosomal localisation of d-tubocurarine.
    Materialart: Digitale Medien
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  • 21
    ISSN: 1432-1017
    Schlagwort(e): Langmuir-Blodgett Layers ; Instability ; Crystallization ; Electron Microscopy ; Infrared Spectroscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Physik
    Notizen: Abstract Results of an investigation of the stability of n-layers of barium stearate, cadmium arachidate and tripalmitin by means of electron microscopy and attenuated total reflection infrared spectroscopy are reported. Odd and even numbered barium stearate n-layers with n=1,2,3.4,5 are found to rearrange spontaneously from a regular film into ultrastructures of irregular, flat islands of varying thickness. The kinetics of the phase transformation of the first layer depends on the substrate, that of n-layers appears to be dependent on n, the temperature, and the surrounding medium. The kinetic behaviour of odd and even numbered layers is distinctly different. Similar studies on cadmium arachidate layers reveal much slower kinetics of the rearrangement process. In the case of tripalmitin n-layers it is shown that electron microscopy and infrared spectroscopy yield valuable complementary information about ultrastructure and molecular structure of the layers in correlation with the rearrangement process, which also occurs with this system. Consequences of the results of this paper for work published in various fields are briefly discussed.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 104 (1975), S. 171-178 
    ISSN: 1432-072X
    Schlagwort(e): Rhizobium ; Bacteriophage ; Electron Microscopy ; Fine Structure ; Optical Diffraction ; DNA ; “Sticky Ends” ; Partial Denaturation ; AT-GC-Map ; Computer Application
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Bacteriophage 16-6-12 of Rhizobium lupini has a long, non-contractile tail and a head which is hexagonal in outline. The tail is 140 nm in length, 11 nm in diameter, and carries a short terminal fiber. Analysis of the tail structure by optical diffraction indicates that it is of the helical “stacked disc” type. After phenol-extraction from purified particles, the DNA of phage 16-6-12 can circularize in vitro. No significant difference in contour length was observed between the linear (14.34±0.28 μm) and circular (14.44±0.24 μm) forms of molecules. After partial denaturation with alkali an AT-GC-map was constructed, which shows an asymmetric distribution of AT- and GC-rich regions. It is concluded that this phage DNA can circularize due to the presence of cohesive ends and that it is not circularly permuted.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 105 (1975), S. 329-333 
    ISSN: 1432-072X
    Schlagwort(e): Piptocephalis ; Electron Microscopy ; Sporangiospore ; Mucorales ; Freeze-Etching ; Merosporangium ; Plasmalemma ; Wall Structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Sporangiospore structure in Piptocephalis unispora Benjamin was studied using light microscopy, freeze-etching, scanning and transmission electron microscopy, and compared with that of other members of the Mucorales. A merosporangial wall, plasmalemmal invaginations, and wall protuberances were demonstrated in sections and their possible significance discussed.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 102 (1975), S. 75-83 
    ISSN: 1432-072X
    Schlagwort(e): Fine-Structure ; Acinetobacter sp. ; Hydrocarbon Inclusions ; Electron Microscopy ; X-Ray Diffraction ; Transport of Hydrocarbons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract 1. The fine-structure analysis of the hydrocarbon oxidizing microorganism, Acinetobacter sp., demonstrated a cytoplasmic modification resulting from growth on paraffinic and olefinic hydrocarbons. 2. Intracytoplasmic hydrocarbon inclusions were documented by electron microscopy with chemical identifications obtained by gas chromatography and X-ray diffraction. 3. These results demonstrate the ability of a micro-organism to accumulate hydrocarbon substrates intracellularly which, in turn, indicates transport across the cell membrane.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 102 (1975), S. 59-64 
    ISSN: 1432-072X
    Schlagwort(e): Membrane Proteins ; Electron Microscopy ; Rhodospirillum rubrum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Intracytoplasmic membranes isolated from Rhodospirillum rubrum, mutant strain VI, were extracted with the detergent lauryl dimethyl amine oxide. Subsequently two fractions were isolated, one of which contained reaction centers and the other contained light-harvesting bacteriochlorophyll of the photosynthetic apparatus. The two fractions are compared with unextracted membranes on the basis of protein patterns obtained by different methods of polyacrylamide gelelectrophoresis. Electron micrographs of the light-harvesting bacteriochlorophyll fraction reveal the presence of vesicular membrane structures. The only difference between such membranes and unextracted membranes is identified after freeze etching. While unextracted membrane surfaces are studded with particles extracted membranes exhibit a smooth surface.
    Materialart: Digitale Medien
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  • 26
    ISSN: 1432-072X
    Schlagwort(e): Candida tropicalis ; Catalase Activity ; Development of Microbodies ; Electron Microscopy ; Utilization of n-Alkanes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Development of microbodies in Candida tropicalis pK 233 was studied mainly by electron microscopical observation. The yeast cells, precultured on malt extract, scarcely contained microbodies and showed very low catalase activity. When the precultured cells were transferred to a n-alkane medium and incubated with shaking, the number of microbodies increased and concomitantly the activity of catalase was enhanced. That is, both the area ratio of microbodies in the cell and the ratio of microbodies to cytoplasm in area increased significantly during the utilization of n-alkanes for 8 hrs. Localization of catalase in the microbodies was demonstrated cytochemically by use of 3,3′-diaminobenzidine, but other organella in the cell, except for vacuoles appearing in the early growth phase and mitochondria, were not stained with this reagent. Microbodies seemed to grow by division. Biogenesis of microbodies in the yeast cells is also discussed.
    Materialart: Digitale Medien
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 103 (1975), S. 91-112 
    ISSN: 1432-072X
    Schlagwort(e): Phytophthora ; Electron Microscopy ; Oogonium ; Oosphere ; Antheridium ; Oospore ; Wall Morphogenesis ; Amphigyny
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Gametangial development and oospore formation were studied, with emphasis on cell wall morphogenesis, on mated cultures (A1xA2) of Phytophthora capsici. In this species, the oogonial and antheridial hyphae interact to produce a typical amphigynous antheridium. The following developmental steps were recognized: 1) contact between oogonial and antheridial initials; 2) penetration of the antheridial initial by the oogonial initial; 3) reemergence of the oogonial initial; 4) oogonial expansion; 5) gametangial delimitation and oogonial wall thickening; 6) penetration of the oogonium by the antheridial fertilization tube; 7) oosphere formation; 8) periplasm degeneration and outer oospore wall formation; and 9) inner oospore wall formation. Electron micrographs were obtained of steps 3–9. Steps 1 and 2 were reconstructed from subsequent events. Steps 3–6 are stages of active wall formation with clear indication of intensive dictyosome activity leading to the formation of numerous wall-destined vesicles of two different sizes and electron densities. No vesicles were seen associated with the development of the inner oospore wall; however, by this stage of development the oosphere cytoplasm exhibited an overall intense electron density that obscured fine detail. Cytoplasmic appearance changed enormously during differentiation, from a developing oogonium rich in mitochondria, ribosomes, rough endoplasmic reticulum, dictyosomes and their vesicles, through an oosphere filled with large “finger-print” vacuoles and lipid-like bodies, to a mature oospore with a large central vacuole (ooplast) surrounded by a cortex of numerous lipid-like bodies; other organelles are confined to the interstitial space between these storage bodies.
    Materialart: Digitale Medien
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 104 (1975), S. 215-223 
    ISSN: 1432-072X
    Schlagwort(e): Mesosome ; Tubular Membranes ; Fine Structure ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Während einer 10tägigen Inkubation als Oberflächenkultur bei 30°C durchliefen Zellen des gramnegativen Bodenbakteriums Pseudomonas rhodos drei Wachstumsphasen, die sich physiologisch und morphologisch voneinander unterschieden. Elektronemikroskopische Untersuchungen an jungen Zellen zeigten Mesosomen in typisch eingerollter Form. In alternden Zellen konnten stattdessen lose gerollte oder langgestreckte, abgeplattet-tubuläre Membransysteme gefunden werden, die als degenerierende Mesosomen gedeutet wurden. Durch Lysozym- oder Ultraschall-behandlung dieser Zellen konnten tubuläre Strukturen isoliert und durch differentielle Zentrifugation angereichert werden. Elektronenmikroskopische Aufnahmen solcher Anreicherungen zeigten lange, abgeplattete Röhren, die gelegentlich an einem Ende geschlossen erschienen. Ihr Durchmesser betrug 34±5 nm. Sie waren mit einer Substanz ausgekleidet, die durch Trypsin abgebaut werden konnte, wobei eine elektronentransparente Matrix freigelegt wurde. Isolierte Tubuli zeigten in einigen Fällen einen periodischen Feinbau aus ellipsoiden Untereinheiten. Die lichtoptische Diffraktions-analyse ergab ein Gitter von Untereinheiten, die in Schrauben mit einer 27°-Steigung angeordnet sind; die Dimensionen der Elementarzelle betragen 112×56 Å. Die Proteinnatur der Gitterkomponenten wurde aus ihrer Trypsinempfindlichkeit gefolgert. Es wird postuliert, daß diese Proteinkomponenten auf einer tubulären Membranmatrix aufgelagert sind. Form und Feinstrukturparameter unterscheiden die Tubuli deutlich von einer periodisch aufgebauten Schicht der P. rhodos-Zellwand mit tetragonalem Gitter sowie von den “polyheads” und “polysheaths” defekter Bakteriophagen. Ihre mögliche Entstehung aus intakten Mesosomen wird diskutiert.
    Notizen: Abstract During a 10 day-incubation on agar surfaces at 30°C, cells of the gram-negative soil bacterium Pseudomonas rhodos pass through three phases distinguishable by physiological and morphological criteria. When viewed by electron microscopy, typically “rolled” mesosomes could frequently be observed in young cells. In aged cells instead, loosely rolled or stretched-out, flattened tubules could be discerned, presumed to be degenerate mesosomes. Tubular flattened structures have been isolated from these cells by lysozyme treatment or sonication and were concentrated by differential centrifugation. Electron micrographs of these preparations showed long, straight tubules which sometimes appeared sealed at one end. Their width was 34±5 nm. They contained a lining of material, which could be digested by trypsin leaving behind an electron-transparent matrix. In rare cases, isolated tubules showed a periodic fine structure composed of ellipsoidal subunits. Optical diffraction analysis yielded a lattice consisting of subunits arranged in helices of pitch-angle 27°; the unit cell dimensions were shown to be 112×56 Å. Owing to their sensitivity to trypsin, components of the regular lattice are supposed to consist of protein. It is postulated that these protein components are layered onto a tubular membrane. These tubules are clearly distinguishable by their shape and fine structure from the periodic structure of a P. rhodos cell wall layer, which exhibits a tetragonal pattern, and also from polyheads and polysheaths of defective bacteriophages. Their possible origin from intact mesosomes is discussed.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 366 (1975), S. 113-123 
    ISSN: 1432-2307
    Schlagwort(e): Pituitary Gland ; Prolactin ; Pituitary Adenoma ; Electron Microscopy ; Histology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Morphologic studies of pituitary neoplasms removed by surgery from 36 human patients revealed 8 chromophobe adenomas which differed clearly from the remaining tumors. The cytoplasm of the adenoma cells failed to stain with PAS, aniline blue, aldehyde fuchsin, aldehyde thionin, orange G or light green, but positively stained granules were found by using erythrosine or carmoisine. Immunoperoxidase technique disclosed the presence of prolactin in the cytoplasm of some adenoma cells. The adenoma cells exhibited distinct ultrastructural features such as well developed rough surfaced endoplasmic reticulum with Nebenkern formation, prominence of Golgi apparatus, presence of misplaced exocytosis as well as pleomorphism of secretory granules with a considerable variation of size ranging from 130 to 500 nm in diameter. Thus, by electron microscopy the adenoma cells showed a close resemblance to prolactin cells of the non-tumorous pituitary glands except for the reduced size and number of secretory granules. These chromophobe adenomas are regarded as representing a distinct pathological entity clearly distinguishable from other forms of pituitary neoplasms. In view of the morphologic findings and the elevation of blood prolactin level (measured in 3 patients) the term, “sparsely granulated prolactin producing pituitary adenoma”, appears to be the most appropriate one to designate these tumors.
    Materialart: Digitale Medien
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 367 (1975), S. 47-57 
    ISSN: 1432-2307
    Schlagwort(e): Noradrenaline ; Catecholamine ; Rat Heart ; Myocardial Necroses ; Optical Microscopy ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Weibliche Wistarratten von ca. 200 g Körpergewicht zeigen nach subcutaner Gabe von 1-Noradrenalin (2,5 mg/kg Körpergewicht) regelmäßig Herzmuskelfasernekrosen. Nach intraperitonealer k-Strophanthin-Prämedikation in therapeutischer Dosierung (2 × 10−5 g/kg Körpergewicht) nehmen Zahl und Ausdehnung der Nekrosen statistisch signifikant zu. Diese Befunde sprechen gegen einen präventiven Schutzeffekt des k-Strophanthins und erklären sieh aus dem biochemischen Wirkungsmechanismus der Katecholamine und Glykoside, indem beide Substanzen gleichsinnig eine Erhöhung des mobilisierbaren intracellulären Calcium der Herzmuskelfaser bewirken. Eine Strophanthin-Prämedikation bewirkt bei den durch Arterenol induzierten Myokardfasernekrosen weder im Verteilungsmuster der Nekrosen noch im elektronenmikroskopischen Befund eine Änderung.
    Notizen: Summary Female rats with a body weight of approximately 200 g regular show necroses of myocardial fibers after subcutaneous injection of 1-Noradrenaline (2.5 mg/kg body weight). After intraperitoneal premedication with Strophanthin k in a therapeutical dosage (2 × 10−5 g/kg body weight), the increase in number and extent of the necroses is statistically significant. These findings argue against a preventive effect of Strophanthin k and can be explained by the mode of action of catecholamines and glycosides, as both substances, in a like manner, cause an increase in the mobilizable intracellular calcium of the myocardial fiber. Premedication with Strophanthin causes no alteration in the distribution pattern of necroses, nor in the electron-microscope findings in the case of myocardial necroses produced by Noradrenaline.
    Materialart: Digitale Medien
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 367 (1975), S. 113-130 
    ISSN: 1432-2307
    Schlagwort(e): Ulcerative Colitis ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Untersuchungen zur Ultrastrukturpathologie der Colitis ulcerosa wurden an einem Kollektiv von 37 Kolitis-Patienten durchgeführt. Unter den epithelialen Veränderungen fallen vor allem Alterationen der Mikrovilli und der Glykokalyx der oberflächlichen Zylinderzellen auf. Möglicherweise könnten diese als morphologisches Substrat eines zumindest partiell gestörten „Mucosablockes” im Bereich der Oberflächenepithelien (IgA- und “secretory piece”-Mangel) gewertet werden. Hypothetisch wird dieser partiell gestörte „Mucosablock” als wesentliches pathogenetisches Moment bei der Colitis ulcerosa angenommen. Das Entzündungsinfiltrat des Stratum proprium mucosae ist vor allem durch zahlreiche Lymphocyten, Plasmazellen und Makrophagen ausgezeichnet. Aus der hierbei gefundenen engen topographischen Zuordnung dieser Zellen zueinander läßt sich eine funktionelle Kooperation bei dem Autoimmunprozeß vermuten, wie er bei der Colitis ulcerosa diskutiert wird.
    Notizen: Summary The ultrastructural pathology of ulcerative colitis was investigated on a group of 37 colitis patients. Among the epithelial changes, the alterations of the microvilli and of the glycocalyx of the surface epithelium are quite evident. These alterations may possibly be understood as a morphological substrate of a partly impaired “mucosa block” of the surface epithelium (IgA- and “secretory piece” deficiency). Hypothetically, this partly impaired “mucosa block” is considered to be an essential pathogenetic moment of ulcerative colitis. The inflammatory infiltrate of the stratum proprium mucosae is characterized in particular by numerous lymphocytes, plasma cells and macrophages. The close topographical interrelation of these cells observed here seems to indicate a functional cooperation in the auto-immunological process, as it is discussed here in connection with ulcerative colitis.
    Materialart: Digitale Medien
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  • 32
    ISSN: 1432-0878
    Schlagwort(e): Islands of Langerhans ; Mitochondria ; Enzymes ; Tissue Culture ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Isolated islets of Langerhans from mice were maintained in tissue culture for one week at either a high (28 mM) or a low (3.3 mM) extracellular glucose concentration. Electron microscopic morphometry by means of stereological methods revealed a much greater volume of mitochondria in islet cells cultured at low glucose than in those cultured at high glucose. The former islets also showed a higher activity of the mitochondrial marker enzyme, L-3-hydroxyacyl-CoA-dehydrogenase (E.C.1.1.1.35). These results indicate a true mitochondrial hypertrophy at the low glucose concentration. Although it is known from previous studies that the islet cell metabolism is diminished after low-glucose culture, the present observations of an increased mitochondrial volume probably do not reflect a degenerative process, but rather adaptive changes towards oxidation of energy yielding substrates other than glucose.
    Materialart: Digitale Medien
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 165 (1975), S. 89-102 
    ISSN: 1432-0878
    Schlagwort(e): Spermiogenesis (teleost) ; Microtubules ; Centriolar complex ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary During nuclear elongation in spermatids of Gambusia affinis, a deep fossa is formed at the base of the nucleus in which the centriolar complex and proximal portion of the flagellum reside. To stabilize the positional relationship between the nucleus and centriolar complex, while nuclear morphogenesis is taking place, a series of microtubules develop which emanate from the centriolar complex and extend to the nuclear envelope lining the fossa. Buttressing microtubules also develop within the nuclear fossa which both originate and insert along the nuclear envelope. These appear to stabilize nuclear shape prior to the time when chromatin condensation has proceeded to the stage where it could lend structural stability to nuclear form. Microtubules develop only after specific nuclear morphogenic events have taken place. It is therefore concluded that the spermatid nucleus is capable of “self-assembly” involving microtubules in a supportive role in addition to stabilizing the nuclear-flagellar relationship in G. affinis. The pattern of nuclear fossa-associated microtubules in G. affinis is significantly different from that observed in other poeciliid teleosts indicating a degree of species specificity with regard to both the timing of appearance and total number of microtubules.
    Materialart: Digitale Medien
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 156 (1975), S. 239-252 
    ISSN: 1432-0878
    Schlagwort(e): Olfactory mucosa ; Sense organs ; Reptilia ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Olfactory epithelium in Tiliqua scincoides scincoides is of a loosely packed pseudostratified type. It receives secretion from the supporting cells and the underlying glands of Bowman. Its surface bears microvilli and cilia from sensory cells and microvilli from supporting cells. The vomeronasal epithelium is also pseudostratified but higher and more closely packed. Its surface carries microvilli from sensory and supporting cells but lacks cilia. Vascular connective tissue penetrates it almost to the epithelial surface but is always outlined by basal cell processes and a basal lamina. There are no secretory cells in or under the sensory epithelium but some cells in the epithelium of the mushroom body contain secretion granules. Sensory cells of both epithelia are bipolar neurons. The perikarya of the vomeronasal cells are more neuronal in character. Axonic processes are similar in both, dendrites are distinctive. Olfactory dendrites end in rounded rods bearing microvilli and cilia of an unusual type. Microvilli with filamentous cores occur on vomeronasal dendrites. There are no cilia, but 2–6 centrioles appear below the cell surface. Basal cells are structurally similar in both epithelia, but axonic processes of olfactory cells are surrounded by supporting cell processes, while vomeronasal axonic processes are surrounded by basal cells before they leave the epithelium. The presence of cilia and microvilli on the surface of the sensory cells is discussed in relation to the physical conditions surrounding them.
    Materialart: Digitale Medien
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 209 (1975), S. 247-262 
    ISSN: 1434-4726
    Schlagwort(e): Acoustic Trauma ; Cochlear Nucleus ; Degeneration ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Meerschweinchen wurden dem Impulsgeräusch von 40 Schüssen einer Startpistole ausgesetzt. Veränderungen in den akustischen Kernen wurden licht- und elektronenmikroskopisch untersucht. 5–55 Tage nach Schallexposition wurde Phagocytose an degenerierenden N. acusticus Endigungen und von Neuronen zweiter Ordnung beobachtet. Es werden verschiedene Hypothesen diskutiert, eine hinreichend überzeugende Erklärung für diese Veränderungen konnte jedoch nicht gefunden werden.
    Notizen: Summary Guinea pigs were exposed to the noise of 40 shots of an alarm pistol held at a distance of about 60 cm. The ventral cochlear nuclei were studied in phase contrast and electron microscopy after both short survival periods and longer periods of up to 55 days survival. Marked degeneration of primary cochlear nerve endings and of synapting secondary neurons of the posterior caudal part of the ventral cochlear nucleus (AVCN) and the octopus cell area (OCA) of the posterior ventral cochlear nucleus (PVCN) was found most distinctly after 5–55 days. As criteria of degeneration of the second neuron of the afferent auditory pathway we used: 1. The loss of the synapting nerve endings, mainly “shrinking”. 2. The formation of huge mitochondria in the second order neurons and their dendrites. 3. The phagocytosis by glial cells of nerve endings, of the second order neurons and of their dendrites. After 5 days survival time no distinct changes were found in the granular cell area of PVCN, where as all stages of degeneration could be found in OCA at this time. In the discussion of these findings it is concluded that additional studies of the morphology of the cochlear nuclei seem necessary, as these may lead to a better understanding of the pathology of hearing following heavy noise exposure.
    Materialart: Digitale Medien
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