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  • 1985-1989
  • 1975-1979  (128)
  • 1800-1809
  • 1976  (128)
  • Electron microscopy  (128)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 369 (1976), S. 181-190 
    ISSN: 1432-2307
    Schlagwort(e): Cerebral hemorrhage ; Cerebral artery disease ; Plasmatic arterionecrosis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An electron microscopic study of the intracerebral arteries from 9 hypertensive cases was performed in order to elucidate the morphogenesis of the plasmatic arterionecrosis which was considered to be the direct cause of hypertensive intracerebral hemorrhage. In the preceding stage of the arterial lesions, marked necrosis of medial smooth muscle cells and increase of basement membrane-like substance in the intima and media were observed. The lumina of these arteries were slightly dilated. The dilatation and hemodynamic factors were supposed to cause endothelial injury resulting in blood plasma insudation into the intima through the opened spaces between endothelial cells. The insudated blood plasma dispersed and dissolved the basement membrane-like substance, collagen and elastic fibers in the arterial wall, leading to the development of the plasmatic arterionecrosis.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 370 (1976), S. 141-150 
    ISSN: 1432-2307
    Schlagwort(e): Angiotensin ; Catecholamine ; Strophanthin ; Rat heart ; Myocardial necroses ; Optical microscopy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei der Ratte nehmen die durch Angiotensin induzierten Herzmuskelfasernekrosen (75 mg/kg s.c. und i.p.) unter Strophanthin-Praemedikation (2 × 10−2 mg/kg i.p.) an Zahl und Ausmaß ab. Darüberhinaus ändert sich der elektronenmikroskopische Befund: Die alleinige Gabe von Angiotensin bewirkt eine Vakuolisation der Mitochondrion und eine Dilatation des endoplasmatischen Reticulum ohne Alteration der Myofibrillen. Die kombinierte Gabe von Strophanthin und Angiotensin führt zu einer primären Zerstörung der Myofibrillen, ohne daß Mitochondrien und tubuläres System sichtbar verändert werden. Der Schutzmechanismus des Strophanthin wird im Sinne einer Ökonomisierung des Zellstoffwechsels bei relativer coronarieller Insuffizienz diskutiert, welche durch die starke vasokonstriktorische Wirkung des Angiotensin ausgelöst wird.
    Notizen: Summary Number and degree of angiotensin-induced heart muscle necroses in the rat (75 mg/kg body weight) are diminuished by premedication with strophanthin (2 × 10−2 mg/kg body weight). The electron-microscopic findings are also changed: the application of angiotensin only results in vacuolization of mitochondria and a dilatation of the endoplasmatic reticulum while myofibrils are unaltered. Angiotensin in combination with strophanthin has a direct destructive effect on the myofibrils without evident changes of the mitochondria and the tubular system of the heart. The protective action of Strophanthin on the heart muscle cell is discussed in the sense of an economization of the cellular metabolism under conditions of relative coronary insufficiency, induced by the vasoconstructive effect of angiotensin.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 370 (1976), S. 273-289 
    ISSN: 1432-2307
    Schlagwort(e): Bone marrow biopsy ; Hairy cell leukemia ; Differential diagnosis ; Myelofibrosis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In 24 patients with hairy cell leukemia, histological and fine structural findings from biopsies of the bone marrow are reported and their validity is compared with other diagnostic procedures available. Diagnosis by light microscopy of anterior iliac crest biopsies obtained by the method of myelotomy is possible with a high degree of accuracy. The differentiation of hairy cell leukemia from other myelo- or lymphoproliferative disorders based on cytomorphology as well as patterns of growth is emphasized. Morphological differences between fibrosis in this entity and other lesions such as malignant lymphomas, Hodgkin's disease, osteomyelofibrosis and -sclerosis are emphasized. Electron microscopy of the bone marrow shows single fibroblastic cells with numerous slender cytoplasmic processes randomly dispersed among the hairy cells. These fibroblasts are probably responsible for the synthesis of the reticulin and collagen fibres in their surroundings. Moreover fine structure of the hairy cells demonstrates pinocytic activity but no apparent phagocytosis in contrast to the phagocytic reticulum cells (histiocytes, macrophages). In the bone marrow the precursor cells and the many immature forms of hairy cells exhibit an overall lymphocytoid appearance during their maturation, suggesting a lymphocytic origin.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1432-2013
    Schlagwort(e): Tissue culture ; Fluorescence histochemistry ; Electrophysiology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Irides from 3–5 day old rats have been grown 1–3 mm from superior cervical or lumbar paravertebral sympathetic ganglia in modified Rose chambers. The two muscles of the iris received distinctly different innervation patternsin vitro, and these were similar to those seenin vivo. Varicose, adrenergic fibres were consistently associated with the dilator pupillae rather than with the sphincter pupillae while excitatory, cholinergic junctions developed between the nerve fibres and the muscle cells of the sphincter but not the dilator. There was a lack of specificity shown by the sympathetic neurons during this innervation. Fibres from lumbar ganglia formed plexuses within the dilator similar to those formed by superior cervical fibres, and sympathetic, cholinergic fibres were able to substitute for the normal parasympathetic, cholinergic fibres in the sphincter.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1432-2307
    Schlagwort(e): Human heart ; Innervation ; Fluorescence histochemistry ; Electron microscopy ; Catecholamines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The existence of both adrenergic and cholinergic innervation of the atrial myocardium of the adult human heart was demonstrated by means of fluorescence induced by formaldehyde or glyoxylic acid and by electron microscopy. The adrenergic fluorescing axons (1) followed the course of blood vessels as typical perivascular nerve plexuses, and (2) formed a three-dimensional fairly dense nerve net obviously not related to the blood vessels. The varicosities frequently came into close apposition on myocardial cells. Several types of nerve terminals were differentiated at electron microscopy: (1) an “adrenergic” type containing small (diameter 450–700 Å) dense-cored vesicles and usually (in various proportions) small “empty” and/or large (900–1500 Å) dense-cored vesicles, (2) a “cholinergic” type containing small (ca. 500 Å) “empty” vesicles and occasionally also some large (mean diameter ca. 1200 Å) dense-cored vesicles, (3) a “pale” type containing only a few or no vesicles, (4) a “disintegrated” type containing degenerated mitochondria, autophagic vacuoles, and occasional normal-looking mitochondria, (5) nerve terminals containing a large number of mitochondria in addition to varying vesicle populations, and (6) a (possibly baroreceptive type of) nerve terminal containing myelinlike lamellated structures. The “disintegrated” and the “pale” types of nerve terminals possibly represent different stages of axonal degeneration, or may correspond to diminution in the transmitter substance concentration under certain pathophysiologic conditions, respectively. Nerve terminals crowded with mitochondria may be sensory and involved in mechano-or chemoreceptive functions. In preliminary experiments convincing evidence was obtained that the glyoxylic acid-induced fluorescence histochemical method will be suitable for comparative studies on (human) clinical specimens, e.g., for analyzing the degree of the functional activity of the intrinsic adrenergic innervation of the myocardium under various pathophysiologic conditions. The modification which appeared most appropriate for such studies is described in detail, and is proposed for use as a standard method in other similar or related studies on human clinical series. The essential criteria for analyzing the specimens at fluorescence microscopy are suggested as well.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 371 (1976), S. 251-263 
    ISSN: 1432-2307
    Schlagwort(e): Human liver ; Electron microscopy ; Stereology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The stereologioal model and the base-line data of normal human liver needle biopsy-specimens are presented. Four reference systems were introduced: 1 cm3 of liver tissue, 1 cm3 of hepatoeyte, 1 cm3 of hepatocytic cytoplasm and the volume of an average “mononuclear” hepatocyte. The sampling was done at three levels of magnification (1,000 ×, 5,000 × and 10,000 ×). A lobular differentiation was not considered. The baseline data show strikingly small variations (s.e. less than 10%) within the individual biopsy specimen and within the group of four biopsies. There is no principal difference between human beings presented here, rats, mice and dogs. Only the mean individual volume of human hepatocytes is clearly larger than in rodents. The problems and limitations of stereological work on liver biopsy specimens are discussed.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 371 (1976), S. 273-282 
    ISSN: 1432-2307
    Schlagwort(e): Nasopharyngeal angiofibroma ; Fibroblast ; Vascular cells ; Fibromatosis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An electron-microscopic study of 9 nasopharyngeal angiofibromas was performed in order to elucidate the ultrastructural characteristics. Stromal fibroblasts and proliferating cells of the microvasculature were found. The stromal fibroblasts were subdivided into 3 different groups: (1) “classical” fibroblasts, (2) fibroblasts with histiocytelike features, and (3) fibroblasts with myoid features. By proliferation the cells of the capillary vessels change into stromal cells. A particular pattern of nuclei and dense intranuclear granules is only found in stromal fibroblasts. Consequently fibroblasts as well as cells of the microvasculature contribute to the pool of tumor cells.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Archives of gynecology and obstetrics 220 (1976), S. 199-208 
    ISSN: 1432-0711
    Schlagwort(e): Rat ovaries ; Diabetes mellitus ; Alloxan ; ATP/ADP ; Lactate/pyruvate ; NADP/NADPH ; Glucose ; Protein content ; Hydrogen-coveying enzymes ; alkal. phosphatase ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Es wurde der Einfluß eines alloxan-induzierten Diabetes mellitus auf den Stoffwechsel und die Ultrastruktur juveniler Rattenovarien untersucht. Der Diabetes mellitus bewirkte folgende Änderungen imStoffwechsel: Abfall der Konzentration von ATP und NADPH, Anstieg des Lactat/Pyruvat-Quotienten über 40, Abfall des ATP/ADP-Quotienten unter 1, Aktivitätsminderung der wasserstoffübertragenden Enzyme G-6-DH, Isocitrat-DH, Malat-DH, Aktivitätszunahme der alkalischen Phosphatase, Erniedrigung des Proteingehaltes.Ultrastruktur: Nahezu vollständiges Verschwinden des rauhen endoplasmatischen Reticulums, Schrumpfung der Mitochondrien, Reduktion der cristae und Kondensation der Matrix. Das glatte endoplasmatische Reticulum bleibt unverändert, der Golgi-Komplex ist in seiner Ausdehnung reduziert. Leichte Extrahierbarkeit der Lipiddepots. Die Befunde sprechen für eine Hemmung der oxydativen Phosphorylierung sowie für eine Beeinträchtigung des Steroid- und Proteinstoffwechsels.
    Notizen: Summary Tests were carried out on the influence of alloxan-induced diabetes mellitus on the metabolism and the ultrastructure of ovaries of juvenile rats. The diabetes mellitus caused the following changes in themetabolism: reduction in the concentration of ATP and NADPH, increase in the lactate/pyruvate quotient to above 40, reduction in the ATP/ADP quotient to below 1, reduction in the level of activity of the hydrogen-conveying enzymes G-6-P-dehydrogenase, isocitrate dehydrogenase and malate dehydrogenase, increase in the level of activity of the alkaline phosphatase, reduction of the protein content. Ultrastructure almost complete disappearance of the rough endoplasmic reticulum, shrinkage of the mitochondria, reduction of the cristae and condensation of the matrix. The smooth endoplasmic reticulum remains unchanged, the extent of the Golgi-complex is reduced. Easy removal of the lipid deposits.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 149 (1976), S. 123-148 
    ISSN: 1432-0568
    Schlagwort(e): Rat-placenta ; Gap junctions ; Electron microscopy ; Freeze-fracturing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The placental labyrinth of the chorioallantoic placenta of the rat was studied with transmission and scanning electron microscopy. Full-term placentas were investigated after perfusion fixation from the maternal and fetal circulation, including thin-sectioning and freeze-fracturing. The labyrinthal three-dimensional structure was found not to be trabecular but spongious lamellar. We propose a division of the lamellae into three groups—the first, second, and third order. The trophoblastic layers are described in detail, showing a cellular layer I and two syncytial layers II and III. Layer I is found to be fenestrated and highly permeable. Layers II and III are connected by extended gap junction areas. It is suggested that the gap junctions function as a molecular sieve and represent the limiting barrier in diaplacental transport of the choriollantoic placenta. Fetal capillaries are fenestrated and endothelial cells are connected by tight junctions. The functional significance of the morphologic findings is discussed.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1432-0533
    Schlagwort(e): Experimental malignant Schwannomas ; Organ culture ; Electron microscopy ; Differentiation ; Microtubules ; Basal lamina ; Perineurial fibroblasts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The sequential electron microscopic features of six malignant nerve sheath tumors (three cranial and three spinal) induced in rats by transplacental ethylnitrosourea and maintained in organ culture systems were compared with those of a human acoustic Schwannoma similarly cultured. After 4 weeks in vitro, the malignant tumor cells often showed progressive elongation of their processes, with the development of an interdigitating pattern resembling that seen in well-differentiated Schwannomas. This was accompanied by an increase of microtubules. Basal lamina formation, less well-developed and less complete than in the benign Schwannoma in this study, was maintained in culture. Some explants demonstrated an increase in number and width of collagen fibrils, accompanied by a relative concomitant decrease of intercellular basement membrane material. The malignant tumor cells also showed numerous micropinocytotic vesicles and various junctional complexes, which are characteristic of perineurial cells. Since the origin of the experimental tumors from adult Schwann cells seems well established, this apparent contradiction is best resolved by the concept that Schwann cells and perineurial fibroblasts are functional variants of the same cell type.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 1-12 
    ISSN: 1432-0533
    Schlagwort(e): Cytoplasmic vacuole ; Oligodendroglia ; Brain edema ; Metastatic carcinoma ; Glioma ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Vacuolation of oligodendroglia, a new type of cytopathological change, has been described. The change is observed frequently at the perifocally edematous cerebral white matter adjacent to the metastatic lesions of carcinoma from the lung in all three cases examined. It is also present occasionally in association with astrocytoma. This condition is characterized by swelling of oligodendroglias due to numerous cytoplasmic vacuolations which contain the material identical with that of the extracellular edema fluid. In such cells, the nucleus is displaced and deformed by vacuoles but the nuclear chromatin and envelopes are arranged normally. By occupation of numerous large vacuoles the cytoplasm is divided into small areas, but the individual organelles are only minimally altered. The oligodendroglial vacuolation seems to be a phagocytic response to the edema fluid which contains proteinous macromolecules derived from blood-borne protein and necrotic material of brain tissue and neoplastic cells. The vacuolation may result in some oligodendroglial dysfunction in maintenance of myelin and probably be related with diffuse loss of myelin sheath in the longstanding brain edema secondary to neoplastic invasion. The vacuolated cells can be identified with light and electron microscopes in Epon-embedded sections of surgically removed tissue but not in paraffin sections.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 329-338 
    ISSN: 1432-0533
    Schlagwort(e): Muscle pathology ; Target muscle fibre ; Targetoid muscle fibre ; Histochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A large number of target fibres is observed in a muscle biopsy from a patient with an acute flaccid paraplegia of the lower limbs due to a polyneuroradiculopathy of unknown origin. With the electron microscope up to 4 structural zones are seen in the target fibers. The histochemical and ultrastructural observations in this case, suggest that the “target fibre” phenomenon is due to a disturbed trophic influence of the nervous system.
    Materialart: Digitale Medien
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  • 13
    ISSN: 1432-072X
    Schlagwort(e): d-Ribulose 1,5-diphosphate carboxylase ; Oxygenase activity ; Quaternary structure ; Electron microscopy ; Alcaligenes eutrophus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract d-Ribulose 1,5-diphosphate carboxylase has been purified from autotrophically grown cells of the facultative chemolithotrophic hydrogen bacteriumAlcaligenes eutrophus. The enzyme was homogeneous by the criteria of polyacrylamide gel electrophoresis. The molecular weight of the enzyme was 505000 determined by gel filtration and sucrose density gradient centrifugation, and a sedimentation coefficient of 18.2 S was obtained. It was demonstrated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis that the enzyme consists of two types of subunits of molecular weight 52000 and 13000. Electron microscopy on the intact and the partially dissociated enzyme lead to the construction of a model for the quaternary structure of the enzyme which is composed of 8 large and 8 small subunits. The most probable symmetry of the enzyme molecule is 4:2:2. Michaelis constant (K m ) values for ribulose 1,5-diphosphate, Mg2-, and CO2 were 0.59 mM, 0.33 mM, and 0.066 mM measured under air. Oxygen was a competitive inhibitor with respect to CO2 suggesting that the enzyme also exhibits an oxygenase activity. The oxygenolytic cleavage of ribulose 1,5-diphosphate was shown and a 1:1 stoichiometry between oxygen consumption and 3-phosphoglycerate formation observed.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 111 (1976), S. 175-183 
    ISSN: 1432-072X
    Schlagwort(e): Serratia marcescens ; (Phage tail) bacteriocin ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Genese eines phagenschwanzähnlichen Bacteriocins in Zellen des Gruppe A-bacteriocinogenen (bA+) Serratia marcescens-Stammer Nr. 16 wurde nach Mitomycin C (MC) Induktion elektronenoptisch untersucht. Dieses Bacteriocin (Gesamtlänge 117 nm) besteht aus einem hohlen Stift mit kontraktiler Scheide. Nach 60 min Induktion wurden in Dünnschnitten stäbchenförmige Bacteriocine identifiziert. Sie erscheinen in drei Aggregationsformen: 1. als hexagonale Einschlüsse, 2. als Bänder dicht nebeneinanderliegender Bacteriocine und 3. als Stapel von übereinanderliegenden Bacteriocinschichten, wenn nach 120 min Induktion ein Maximum von ca. 450 Bacteriocinen pro Zelle erreicht wird. Bacteriocine konnten nach der gleichen Induktionszeit von 60 min auch mit der “in situ lysis technique” nachgewiesen werden. Neben Bacteriocinen traten relativ selten und unregelmäßig auch Phagenköpfe auf. Die Stäbchenform teilungsfähiger Zellen blieb bis zum Auftreten von intracellulären Bacteriocinen erhalten. Ihre Umwandlung in geblähte, sphäroplastenähnliche Zellformen, die nach 120 min Induktion lysierten, war zeitlich korreliert mit Feinstrukturveränderungen der Zellwand.
    Notizen: Abstract The biosynthesis of a phage tail-like Bacteriocin by cells of the group A-bacteriocinogenic (bA+ Serratia marcescens strain no. 16 after induction with mitomycin C (MC) was examined electronmicroscopically. This bacteriocin (total length 117 nm) consists of a hollow core and a contractile sheath. At 60 min following induction, rod-like bacteriocin-partieles were identifiable in ultrathin sections. The particles were found to comprise three morphologically different forms of aggregation: 1. hexagonal inclusions, 2. contiguous, bank-like particles, and 3. staples of superimposed layers of bacteriocin particles. At 120 min after induction bA+ cells revealed maximally 450 bacteriocin particles. Similarly, the phage tail particles could be demonstrated with the “in situ lysis technique” at 60 min following induction. Occasionally, phage heads were demonstrable, but in no instance were complete phage particles discernible. Dividing cells of the bA+ strain of S. marcescens maintained their rod-form following induction with MC until intracellular phage tail bacteriocin particles were seen. However, at 120 min after induction, the swollen, sphaeroplast-like cells lysed, an event that could be correlated with fine structural alterations of the cell wall.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 108 (1976), S. 231-242 
    ISSN: 1432-072X
    Schlagwort(e): Phytophthora ; Penetration ; Eucalypts ; Roots ; Electron microscopy ; Appressoria ; Plugs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The mechanisms of penetration of Phytophthora cinnamomi Rands into seedling eucalypt roots were studied by light and electron microscopy. Culture grown seedlings of root-rot tolerant Eucalyptus st johnii and root-rot susceptible Eucalyptus obliqua were inoculated with both zoospores and mycelium. Zoospores encysted on roots of both species and the germ tubes penetrated without the formation of appressoria. Swellings, previously described as appressoria, were formed when the germ tube was slow to enter the host by intracellular penetration. Vegetative hyphae penetrated both inter- and intracellularly into the zones of root elongation and differentiation, often through root hairs. Evidence of hydrolysis of the host cell-wall at the point of penetration was observed in electron micrographs. Several hours after the germ tube penetrated the epidermis, a thick plug of amorphous material formed in the germ tube slightly below the level of the outer walls of the epidermal cells, sealing off the hypha within the root. Behaviour of zoospores and germ tubes and the mechanism of penetration were similar on both hosts. Micrographs do not suggest any kind of a hypersensitive reaction by the host cells during the early stages of infection.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 99-107 
    ISSN: 1432-072X
    Schlagwort(e): Piptocephalis unispora ; Mucorales ; Kickxellaceae ; Electron microscopy ; Germination ; Spore swelling ; Sporangiospore
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Germination of the sporangiospore of Piptocephalis unispora Benjamin, observed by means of light and electron microscopy, involved the formation of a new inner wall which became continous with the inner layer of the wall of the germ tube. The outer wall layer of the germ tube was continous with the original inner wall layer of the dormant spore. Preliminary details of appressorium structure were noted. Nutritional experiments indicated that sporangiospores required external sources of utilisable nitrogen and carbon compounds for maximal swelling and germ tube production. Limited development occurred when either nutrient was supplied singly. Comparison of germination of the asexual spore with that in other Mucorales, especially the Kickxellaceae, has been made, and the merosporangial status in P. unispora discussed.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 113-114 
    ISSN: 1432-072X
    Schlagwort(e): Achlya ; Electron microscopy ; Nuclear microfilaments ; Antheridia ; Mycology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This is the first report of intranuclear microfilaments within gametangial nuclei of oömycetous fungi. Longitudinal sections of four to six microfilaments were frequently observed in meiotic antheridial nuclei of Achlya ambisexualis. Each microfilament measured approximately 7–10 nm in diameter. Spindle tubules (25 nm in diameter) were also observed within some of the nuclei possessing microfilaments.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 167-182 
    ISSN: 1432-072X
    Schlagwort(e): Ectothiorhodospira mobilis ; Photosynthetic membranes ; Electron microscopy ; Isolation of membranes ; Structure of membranes ; Composition of membranes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The lamellar membrane stacks of Ectothiorhodospira mobilis were isolated and purified by a combination of lysozyme and osmotic shock treatment, followed by differential and density gradient centrifugation. Preparations of lamellar membranes were enriched at least 2.4-fold in the ratio of bacteriochlorophyll a to protein. Thin-sectioning, negative staining, platinumcarbon shadowing and freeze-etching were used to study the architecture of the membrane units. Both platinum-carbon shadowing and freeze-etching showed the outer surfaces of the isolated lamellar membrane stacks to be relatively smooth. Particles averaging 7 nm in diameter were seen on several faces following freeze-ctching. Non-polar amino acids amounted to 60% of the total amino acid composition. Lipids constituted 32% of the membrane dry weight. Phosphatidyl ethanolamine and diphosphatidyl glycerol were the major phospholipids. Fatty acids of 10–15 carbons represented a small fraction of both membrane and whole cell fatty acids. Monoenes constituted 36% of the total membrane fatty acids and 38.4% of the total whole cell fatty acids. The major fatty acids of both whole cells and purified membranes were C16:0, C18:1 and cyclopropane C19:0.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 109 (1976), S. 195-197 
    ISSN: 1432-072X
    Schlagwort(e): Cell wall ; Peptidoglycan ; Electron microscopy ; Bacillus subtilis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Isolated cell walls of Bacillus subtilis have a striated appearance in the electron microscope. The structure persists when teichoic acids are removed. It is inferred that the structure bears on the arrangement of the peptidoglycan chains.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 313-320 
    ISSN: 1432-072X
    Schlagwort(e): Micrococcus radiophilus ; Micrococcus radioproteolyticus ; Bacterial cell walls ; Fine structure ; Electron microscopy ; Taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The radiation resistant bacteria Micrococcus radiophilus and M. radioproteolyticus were studied by thin sectioning and freeze-etching techniques and the two species were found to be similar in the fine structure. The only significant difference was in the appearance of the surfaces of the cell walls in freeze-etched preparations. Since the two species, together with M. radiodurans, possess a unique cell wall structure and a cell wall peptidoglycan, which is different from that of other micrococci and Gram-positive cocci, it is recommended that they be reclassified into a new genus.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 108 (1976), S. 55-64 
    ISSN: 1432-072X
    Schlagwort(e): Bdellovibrio ; Spirillum ; Cell wall ; Bdelloplast ; Lipoprotein ; Peptidoglycan ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In both freeze-etched and critical-point dried preparations examined by transmission and scanning electron microscopy, respectively, the outer surfaces of the cells of Spirillum serpens VHL assume a wrinkled appearance 10–15 min after challenge by Bdellovibrion bacteriovorus 109D. This wrinkling effect is believed (on circumstantial evidence) to be caused by the bdellovibrio's disruption of the cell wall lipoprotein of the Spirillum. With the exception of those topological changes caused by wrinkling, the outer membrane of the Spirillum cell wall retains a normal appearance as viewed in freeze-etched preparations, even after the Spirillum cell has been converted into a bdelloplast. Although the peptidoglycan layer of the Spirillum cell presumably is weakened somewhat by the invading Bdellovibrio, evidence obtained from freeze-fractured preparations of Spirillum bdelloplasts suggests that the peptidoglycan remains as a discrete cell wall layer, even though the Spirillum cell wall apparently has lost much of its rigidity. That the peptidoglycan backbone remains essentially intact, even after the Spirillum cell has been entered by the Bdellovibrio, is supported by the observation that the soluble amino sugar content of the culture medium, as determined by chemical analysis, does not rise even 5.0 h after the association of the Bdellovibrio with the Spirillum has begun.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 109 (1976), S. 21-30 
    ISSN: 1432-072X
    Schlagwort(e): Electron microscopy ; Allomyces ; Gametes ; Fertilization ; Membrane fusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The gametes and the process of fertilization were examined by light and electron microscopy in the lower eukaryote Allomyces macrogynus. Differences in gamete morphology included the overall larger size and the presence of a larger nuclear apparatus, along with the association of a side-body complex and many more mitochondria in the female gamete. In this species of Allomyces, fertilization was initiated by contact and fusion of specialized regions of the gamete plasma membranes resulting in a binucleate fusion cell surrounded by plasma membrane contributed by both partners. Following plasmogamy, nuclear fusion was initiated by multiple nuclear membrane contacts between adjacent outer membranes. Following inner membrane fusion, small nucleoplasmic bridges were observed which presumably fused with one another and resulted in a single bridge which widened, forming the mature diploid nucleus. After karyogamy, fusion of the nuclear caps did not always occur and zygotes with and without fused caps were observed. Coalescence of the nucleoli completed the events of fertilization, forming a zygote with a single nuclear apparatus (sometimes with two caps) and two flagella. These observations are discussed in relation to fertilization mechanisms and compared to fertilization in other organisms.
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Archives of gynecology and obstetrics 221 (1976), S. 277-287 
    ISSN: 1432-0711
    Schlagwort(e): Electron microscopy ; Endocrinology ; Pathology ; Testicular feminization ; Testis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Testicular tissue was investigated by electron microscopy in a case of testicular feminization. The seminiferous tubules were lined by spermatogonia and by Sertoli cells. Spermatocytic maturation was not observed. Leydig cells were numerous and contained well developed, abundant vesicular smooth-surfaced endoplasmic reticulum and large mitochondria with tubulovesicular cristae. Reinke crystalloids were absent. The ultrastructural findings were consistent with the assumption that Leydig cells were under adequate stimulation and were in a stage of active secretion. Hence, the results seem to indicate that testicular endocrine function was maintained in the studied case.
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 183-197 
    ISSN: 1432-0533
    Schlagwort(e): Lewy body ; Electron microscopy ; Parkinsonism ; Dense core vesicles ; Catecholamines ; Mitochondrial inclusions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The Lewy body, a characteristic nerve cell inclusion in idiopathic parkinsonism, was examined by electron microscopy in the stellate ganglion, obtained from 9 patients at autopsy. Three main forms of Lewy bodies or Lewy body-related structures were demonstrated: A. Rare filamentous Lewy bodies, similar to Lewy bodies in the central nervous system. B. Granular Lewy bodies in nerve cell processes. C. Abnormal nerve cell processes, filled with heterogenous material. Large dense core vesicles were prominent in the last 2 forms. None of these abnormalities were found in 2 control groups consisting of 9 parkinsonism cases without central nervous system Lewy bodies, and 17 cases without parkinsonism. The filamentous Lewy body (type A) was found in the perikaryon and was surrounded by neuromelanin, whereas the other forms (type B and C) were seen in nerve cell processes. Mitochondrial inclusions, present mainly, but not exclusively, in neuromelanin-containing cells, were not related to Lewy body formation or to parkinsonism.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 13-25 
    ISSN: 1432-0533
    Schlagwort(e): Chordoma ; Tissue and organ culture ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Explants of a human sacral chordoma were successfully maintained on collagen-coated coverslips, gelfoam sponge matrices, and Millipore filter platforms for up to 30 days. Tumor cells cultured on collagen-coated coverslips became increasingly vacuolated whereas those maintained in organ culture were entirely free of vacuoles after 22 days in vitro. A single basic tumor cell, small and polygonal with a large central spherical nucleus and abundant endoplasmic reticulum and Golgi apparatus, was recognized. Vacuoles were formed as the result of the progressive expansion of smooth endoplasmic reticulum. Coalescence of these vacuoles produced the physaliferous cell of light microscopy.
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 139-150 
    ISSN: 1432-0533
    Schlagwort(e): Electron microscopy ; Olfactory esthesioneurocytoma ; Neurosecretory granules ; Microtubules ; Dystrophic axons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary One case of malignant tumour of the left nasal cavity is reported in a woman 56 year old, affected by the disease 24 years. Numerous recurrences appeared and various histological diagnoses were performed. At the last surgery, the tumour invaded the ethmoïd and was a typical olfactory esthesio-neurocytoma. By electron microscopy, mature ganglion cells with dense cored vesicles (neurosecretory granules) were densely packed. Neuritic processes with microtubules were rarely normal in size and their content was most often abnormal; furthermore dystrophic axons were noted in great number.
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  • 27
    ISSN: 1432-0533
    Schlagwort(e): Neurinoma ; ENU ; Prenatal carcinogenesis ; Transplantability ; Metastases ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary With a single dose of 80 mg/kg ENU, a tumour originating from the trigeminal nerve was induced transplacentally in the offspring of a Sprague-Dawley rat. The neoplasm diagnosed as a neurinoma, was transplanted over 20 passages to 5 six-month-old Sprague-Dawley rats in each case. During this time, the biological behaviour of the tumour as well as its histological appearance were followed. Ultrastructural observations were made of the 20th passage. The tumour caused multiple metastases in the lung and in the lymph nodes of the neck in 30 animals. Recurrences were formed within a week, metastases of the lung appeared from then on in all cases. During the time of transplantation, the neurinoma dedifferentiated histologically so markedly that it was no longer possible to classify the neoplasm as a neurogenous tumour after 20 passages. Ultrastructurally, poorly differentiated Schwann cells could nervetheless be recognized.
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 295-305 
    ISSN: 1432-0533
    Schlagwort(e): PKU bodies ; Demyelination ; Dysmyelination ; Neuroglia ; Inborn errors of metabolism ; Phenylketonuria ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of various inclusions within oligodendroglial cells in the brains from two phenylketonuric patients was studied. Characteristic lamellar, oval, slightly irregular inclusions measured between 0.5 and 2 micra in diameter and were bounded by a single membrane. The longitudinal and transverse lamellae of these inclusions had a distinct pattern. In analogy to lamellated but different inclusions of other diseases, these structures were termed “PKU bodies”. Various possibilities that would explain the morphogenesis of the PKU bodies and other inclusions in the oligodendroglial cells, and the significance of these findings, are discussed.
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 321-327 
    ISSN: 1432-0533
    Schlagwort(e): Muscle fibres ; Amyotrophic lateral sclerosis ; Werdnig-Hoffmann disease ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Muscle biopsies from 5 cases of Werdnig-Hoffmann disease and 4 cases of ALS were investigated by histology and electronmicroscopy. The differences in morphology found in the atrophic muscle fibres in ALS and in W.H. diesease consisted mainly in the shape and structure of their cells and the number of the nuclei. Atrophic muscle fibres irregular in shape and size with degenerative changes and accumulated nuclei observed in ALS were markedly different from the picture of the fibres in W.H. disease. The presence of small muscle cells uniform diameter with well preserved architecture and single nuclei and numerous myotube-like cells seem to indicate a foetal defect in children with W.H. disease.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 47-54 
    ISSN: 1432-0533
    Schlagwort(e): Entrapment neuropathy ; Fusiform nerve enlargement ; Segmental demyelination ; Axonal changes ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This paper reports on the study of a symptomless fusiform enlargement of the superficial peroneal nerve. The swelling was located in the part of the nerve passing through the aponevrosis. On incision of the epineurium small swellings were seen in the nerve fascicles. A fascicular biopsy was done and the fascicles studied by teasing and by optic and electron microscopy. Isolated nerve fiber study gave evidence of segmental demyelinisation with subsequent remyelinisation in almost all the myelinated fibers. These abnormalities were only encountered in the swollen part of the fascicle. A striking proliferation of cells was demonstrated in isolated fibers by counter-staining with hematoxylin. Electron microscopy showed primary demyelinsation and cellular proliferation affecting Schwann-cells (without onion bulb formations), fibroblasts and giant-vacuolated histiocytes. There was also a massive increase of endoneurial fluid. A few Büngner bands were seen. These rare abnormalities appear to be caused by chronic irritation of the nerve in its passage through the aponebrosis.
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 207-218 
    ISSN: 1432-0533
    Schlagwort(e): Immunomyopathy ; Muscle disease ; Electron microscopy ; Experimental muscle pathology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An experimental model of the autoimmune process was developed to study the ultrastructural aspects of immunomyopathies. Every type of muscle fibre organelle was affected and the severity of injury increased in direct proportion to time following immunization. It is suggested that ultrastructural methods are useful in studies concerned with the analysis of structural aspects of experimental immunomyopathies.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 137-152 
    ISSN: 1432-0533
    Schlagwort(e): Trembler mouse ; Peripheral neuropathy ; Electron microscopy ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The Trembler mouse is a neurological mutant showing dominant inheritance. The peripheral nerves show a delay in myelination, segmental demyelination and the development of an onion bulb neuropathy. Using electron microscopy a comparative morphometric study of nerve fibres in the sciatic nerve in normal and Trembler mice was made. The animals ranged in age from 3 days to adult. The following features were noted: 1. Mean axon diameters of the Trembler mice were smaller than normal at all ages. 2. Myelination was delayed and myelin was thinner than normal in the Trembler mice. 3. The ratio of myelin thickness to axon diameter was reduced in Trembler mice. 4. There were no significant quantitative or qualitative differences observed between middle and distal levels of Trembler nerves. The balance of evidence from these findings and the previous morphological studies is in keeping with the suggestion that the primary lesion resides in the Schwann cell.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 369-379 
    ISSN: 1432-0533
    Schlagwort(e): Leukodystrophy, metachromatic ; Prenatal diagnosis ; Sulphatide accumulation ; Myelination, central, peripheral ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Light and electronmicroscopic findings are reported in a case of metachromatic leukodystrophy diagnosed prenatally who died after iatrogenic abortion during the 23th week of gestation. The brain of this foetus was not yet myelinated while the spinal cord showed early, and the peripheral nerves advanced myelination. The onset and the degree of myelination were similar as in a normal foetus of the same age. Ultrastructurally there was evidence of sulphatide storage before the beginning of myelination. During myelination lysosomal storage material, staining metachromatically in acid cresyl violet preparations, appeared in oligodendrocytes and Schwann cells. Besides sulphatide storage material, prominent amounts of neutral lipids were found in oligodendrocytes. Myelin breakdown was encountered very seldom.
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  • 34
    ISSN: 1432-0533
    Schlagwort(e): Experimental malignant Schwannomas ; Melanin and melanogenesis ; Tissue and organ culture ; Electron microscopy ; Pigmented nerve sheath tumors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Four melanin pigment-containing intracranial tumors were found in three Long-Evans rats in the course of experimental oncogenesis by transplacental ethylnitrosourea (ENU). One of them was a leptomeningeal melanoma. Aside from the presence of scattered melanin-pigmented cells, the other three had the typical histological features of ENU-induced malignant nerve sheath tumors. Two of the three tumors were studied by electron microscopy and in tissue and organ culture systems. One of them demonstrated progressive melanogenesis in vitro; the other failed to produce more melanin and showed increasing differentiation, with a Schwannoma-like pattern by light microscopy. Melanosomes and premelanosomes were identified in both tumors by electron microscopy; the other fine structural features were those of malignant Schwannomas. These observations are relevant to the controversy on the histogenesis of pigmented nerve sheath tumors occasionally encountered in man and on the relationship of these tumors to pigmented nevi. The findings in the present study support the view of Masson that neoplastic nerve sheath cells are capable of melanogenesis.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 93-107 
    ISSN: 1432-0533
    Schlagwort(e): Substantia nigra ; Gunn rat ; Complex membranous bodies ; Bilirubin ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The substantia nigra of various aged hyperbilirubinemic (Gunn) rats was studied by means of electron microscopy. The cytological features observed in the neuronal somata were the presence of (1) complex membranous bodies (CMBs), (2) dilated cisternae of granular endoplasmic reticulum, (3) single membrane bound vacuoles and (4) enlarged mitochondria. Nearly every neuronal soma studied in two week old Gunn rats contained CMBs, which consisted of several layers of membrane that usually, but not always, surrounded small islands of cytoplasm. On occasion CMBs were seen to be directly connected with granular endoplasmic reticulum and, in a few instances, they were located within a cistern of endoplasmic reticulum. There were significantly fewer CMBs in the neuronal somata of adult Gunn rats. They were located peripherally in the somata or in the proximal portions of dendrites. Furthermore, in these animals the cytoplasm appeared normal and did not exhibit the features commonly seen in younger animals. Only a few hyperchromatic neurons were observed and no pronounced gliosis was evident. Therefore it is assumed that the majority of substantia nigra neurons recovered from the toxic effect of bilirubin or that the concentration of bilirubin deposited in the substantia nigra is not sufficient to be lethal. The hypothesis that is considered is that CMBs represent autophagic activity which results from exposure of neurons to bilirubin. The adjacent neurites and glia did not demonstrate the cytoplasmic changes that were characteristic of the neuronal somata.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 31-38 
    ISSN: 1432-0533
    Schlagwort(e): Whipple's disease ; Central nervous system ; Granulomatous infiltration ; Electron microscopy ; Bacillary bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Whipple's disease presenting as a neurological disease without gastrointestinal symptoms is an unusual occurrence. A 40 year old man suffered hypersomnia, memory loss and progressive ophthalmoplegia for 6 months prior to death. The nature of his disease was not established during life. Extensive granulomatous inflammation affecting the hypothalamus, hippocampus and periaqueductal gray matter of the brain was found to represent Whipple's disease by electron microscopy. Characteristic lesions were also present in spleen, mesenteric lymph nodes, small intestine and myocardium. Bacillary bodies and membranous inclusions similar to those seen in visceral lesions of Whipple's disease were present in macrophages. The findings supported the theory of direct involvement of the central nervous system by bacilli rather than a metabolic origin for the lesions.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 211 (1976), S. 111-124 
    ISSN: 1432-1459
    Schlagwort(e): Peripheral nerve ; Peroneal muscular atrophy ; Nerve biopsy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei 2 Patienten mit progressiver neuraler Muskelatrophie wurden Nervenbiopsien jeweils in einem frühen und in einem fortgeschrittenerem Stadium der Erkrankung entnommen und verglichen. In beiden Fällen zeigten bereits die frühen Biopsien ein völliges Fehlen der großkalibrigen, dickbemarkten Axone. Ebenfalls als frühe Veränderung wurde eine Erweiterung des endoneuralen Interstitiums festgestellt. Eine geringe Anzahl der vorhandenen bemarkten und unbemarkten Axone in allen Biopsien wies degenerative Veränderungen auf. Die für die progressive neurale Muskelatrophie typische Zwiebelschalenbildung der Schwannschen Zellen — möglicherweise eine Reaktion auf wiederholte De-und Remyelinisierungsvorgänge um dystrophische Axone — trat erst in den späteren Biopsien deutlicher hervor. Hinsichtlich der formalen Genese der hypertrophischen Neuropathie bei neuraler Muskelatrophie sind nach diesen Beobachtungen axonale Dystrophie und interstitielle Veränderungen des Endoneuriums als primäre Entmarkung und Zwiebelschalenbildung als sekundäre Phänomene zu betrachten. Die Möglichkeit einer kausalen Beziehung zwischen axonaler Dystrophie und interstitiellen Veränderungen wird an Hand der vorliegenden Befunde und Literatur diskutiert.
    Notizen: Summary Serial nerve biopsies were performed at an early, and at an advanced stage of the disease in 2 patients with progressive neural muscular atrophy. The early biopsy showed a complete loss of the large diameter and thickly myelinated fibres, as well as an expansion of the endoneurial interstitium in both cases. Myelinated and unmyelinated fibres exhibited axonal degeneration in all biopsies occasionally. “Onion bulb” formation, a typical feature of peripheral neuropathy in neural muscular atrophy, was found to be prominent only in the latter biopsies. As regards the formal pathogenesis of hypertrophic neuropathy in neural muscular atrophy, axonal dystrophy and interstitial changes of the endoneurium were regarded as primary phenomena, demyelination and “onion bulb” formation as secondary. A possible causal relation between axonal dystrophy and interstitial changes, observed in these cases, is discussed in the light of the present literature.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 214 (1976), S. 27-48 
    ISSN: 1434-4726
    Schlagwort(e): Mononuclear Phagocytic System (MPS) ; Macrophages ; Rhinosinusitis ; Immunology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Neither the concept of the Reticulo-Endothelial-System (RES) Aschoff's (1924) nor that of the Reticulo-Histiocyte-System (RHS) provides a satisfactory framework into which the present knowledge of the phagocytic mononuclear cells can be fitted. Current knowledge concerning morphology, histochemistry (peroxydase and esterase activity), immunology (specific surface antigens, receptors on the cell membranes), function (immune phagocytosis, pinocytosis), kinetics (3H-thymidine labelling) and culture makes it possible to place all highly phagocytic mononuclear cells and their precursors in one system, which is called the Mononuclear-Phagocytic-System (MPS) (Langevoort, Conn, Hirsch, Humphrey, Spector, van Furth, 1969). Kinetic studies with labelled cells have shown, that mononuclear phagocytes originate from precursor cells in the bone marrow (stem cell → monoblasts → promonocytes), than are circulating in the peripheral blood as monocytes and are transformed to tissue macrophages entering tissues. The MPS comprises following cells in following organs: connective tissue (histiocytes resp. macrophages); liver (Kupffer-cells); lung (alveolar macrophages); lymph nodes (free and fixed macrophages); bone marrow (macrophages); serous cavities (pleural and peritoneal macrophages); bone tissue (osteoclasts?); nervous system (microglial cells) (see Table 1). The reticular cells, endothelial cells and fibroblasts (fibrocytes) can therefore not be included in the MPS. Besides differences in morphology, histochemistry and function, they derive from mesenchymal cells and not from the bone marrow as the MPS. The present investigation demonstrates the structure and significance of the MPS in various kinds of chronic-specific and non-specific rhinosinusitis. On semithin sections two kinds of macrophages can be distinguished light-microscopically: 1. Larger macrophages with many phagosomes (storage cells) (Fig. 1A), which can exhibit sometimes a ring-shape on sections embracing greater parts of the interstitium (Fig. 1B). Such forms are mainly found in chronic (maxillary) sinusitis and are interpretated as “scavenger” macrophages. 2. The second type consists of smaller macrophages with extremely ruffling of the cell surface, wich is interpretated as an expression of highly (specific?) stimulated states. These later macrophages can be seen mainly in edematous nasal polyps, which might be caused by allergic reactions of the anaphylactic type. The fine structure of the phagocytes is to some extend dependent on the actual development and functional state: there are “immature” macrophages, which are practically indistinguishable from blood monocytes (Fig. 2A); some of them can be stimulated and can therefore show many surface foldings and projections (Fig. 2B). The “mature” macrophage shows a well developped Golgi-area and many secondary lysosomes (Fig. 3). The storage type of the macrophages, which can predominate in some cases of chronic maxillary sinusitis, is characterized by many electron-lucent vacuoles (Fig. 4). The macrophages can transform unspecifically to epitheloid- and giant-cells, as it is shown in foreign bodys- and cholesterol-granulomas in maxillary sinusitis (Fig. 5A and 5B). This tranformation to epitheloid and giant-cells might also be induced specifically by stimulated T-lymphocytes in immunological reaction of the delayed type, for example in sarcoidosis (Fig. 6A) and tuberculosis (Fig. 6B) of the nose. The macrophage is not only of great importance as the carrier of the cellular immunity in the sense of Metschnikoff (1905), but he is also involved in the initiation and regulation of the specific humoral and cellular immune responses. These facts and the phagocytic and synthetic properties of the macrophages are discussed in regard to their significance for the etiology and course of chronic rhinosinusitis.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Research in experimental medicine 168 (1976), S. 219-227 
    ISSN: 1433-8580
    Schlagwort(e): Initial phase of neurogenic pulmonary edema ; Perfusion fixation ; HRP ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The initial phase of pulmonary edema development following intracranial pressure elevation was studied by means of transmission electron microscopy. Using perfusion fixation and application of a blood tracer (HRP horseradish peroxidase) the time sequence and site of fluid leakage out of pulmonary vessels was demonstrated: - passage of edema fluid through intercellular clefts of alveolar capillary endothelium - edema accumulation in alveolar interstitial tissue - draining of edema fluid from the alveolar septum to the interstitium of terminal bronchioli and to lymphatic vessels. An early interepithelial fluid leakage out of the alveolar wall remains questionable.
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  • 40
    ISSN: 1432-1106
    Schlagwort(e): Rolando substance ; Degeneration ; Atrophy ; Axotomy ; Histochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Disappearence of fluorid-resistant acid phosphatase activity from the ipsilateral Rolando substance after transection of the peripheral nerve, is shown to be due to the cessation of enzyme supply from dorsal root ganglion cells to their central terminals. This is accompanied by (or ensues in consequence of) a fine structural derangement of these terminals (“degenerative atrophy”). Fine structural alterations of axon terminals undergoing degenerative atrophy, though similar to some extent to those seen during early phases of a Wallerian degeneration, are markedly different. Also myelinated nerve fibers, both in the dorsal horn and in dorsal columns, are affected by degenerative atrophy. This important, new trophical feature of sensory ganglion cells suggests a delicate metabolic balance between peripheral and central axonal branches of bipolar (pseudounipolar) cells. Degenerative atrophy raises serious implications in evaluating hodological experiments based upon Wallerian degeneration and offers new perspectives for theoretical and clinical neurology.
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  • 41
    ISSN: 1573-0832
    Schlagwort(e): Trichophyton mentagrophytes ; Thiocyanatopyrazole derivatives ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Four thiocyanatopyrazole derivatives were synthesized and their fungistatic activity was demonstrated in vitro against a number of dermatophytic fungi. In Trichophyton mentagrophytes, the most active compound induced an unusual increase of the plasma membrane with production of intra and extracytoplasmic complexes, a deterioration of nuclear and mitochondrial membranes and a formation of autophagic-like vacuoles. Plasmolysis, accompanied by an almost complete disorganization of cytoplasmic structures, seemed to be the final event. A possible mechanism of action of the compounds was discussed.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 169 (1976), S. 123-128 
    ISSN: 1432-0878
    Schlagwort(e): Venous endothelium ; Adrenaline infusion ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of the endothelium lining the femoral and mesenteric veins in the rabbit was examined following the infusion of concentrations of adrenaline varying from 0.5 to 5.0 μg/kg. Control animals were infused with saline. Vesiculation of the endothelial cells was observed following each infusion of adrenaline, the effect being most marked with the highest dose used. It is suggested that this vesiculation may be associated with the release of antihaemophilic globulin and/or plasminogen activator from the endothelial cells.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 179-195 
    ISSN: 1432-0878
    Schlagwort(e): Islets of Langerhans ; Horse pancreas ; Cell types ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Das Inselorgan der Bauchspeicheldrüse des Pferdes wurde an immersions- und perfusionsfixiertem Material untersucht. Dabei ließen sich nach der Immersions- wie Perfusionsfixation fünf Zelltypen unterscheiden: 1. A-Zellen, die im Zentrum der Insel liegen, 2. B-zellen, die hauptsächlich blasse Granula enthalten und den größten Teil der Inselperipherie ausmachen, 3. D-Zellen, die ebenfalls vorwiegend in der Inselperipherie liegen, 4. G-Zellen, die am Rand der Inseln und im exokrinen Pankreas anzutreffen sind, 5. S-Zellen (“small granule cells”), die relativ selten und nur in den Inseln zu finden sind. Über die Funktion und altersabhängigen Veränderungen dieser Zellen wird diskutiert. Die Bildung von hellen und dunklen Zellen halten wir für ein Artefakt, ebenso die Bildung von sog. Mischzellen, da diese Zelltypen nur nach Immersionsfixation auftreten.
    Notizen: Summary The islets of Langerhans of the equine pancreas were examined with the electron microscope after immersion or perfusion fixation. Five cell types could be distinguished after fixation by either technique: 1. A-cells, situated at the center of the islets, 2. B-cells, containing mostly “pale granules” and constituting the principal cell type of the periphery of the islets, 3. D-cells, also located mainly at the periphery of the islets, 4. G-cells, found at the edge of the islets and in the exocrine pancreas, and 5. S-cells, (small granule cells), which are relatively few in number and occur only in the islets. The function and age-dependent modifications of these cells are discussed. The formation of light and dark cells and of “mixed cells” are regarded as artifact, since cells of this type occur only under the condition of immersion fixation.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 265-288 
    ISSN: 1432-0878
    Schlagwort(e): Myelinated fibres ; Visual cortex ; Stereology ; Development ; Electron microscopy ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary With the aid of stereological procedures the development of myelinated nerve fibres (MF) was quantitatively investigated in electron micrographs of the visual cortex from animals of different ages: 36 days-old, the age at which fibres first appear, through adulthood. A short description of tissue treatment, methods and qualitative results is given. The following quantitative results are presented: 1. Myelinization begins at about the 36th day postpartum and is not completed by the 164th day. At this time a lack of about 20% MF can be observed. 2. The average diameter of MF decreases from 1.3 μm to 0.8 μm from day 36 to adulthood. 3. The first MF appear near the border of the album. 4. Beginning with the 55th day, small MF arise in layer I, showing two periods of growth. 5. The maximum MF density in the region of layer IV corresponds to the strip of Baillarger. Other aspects of visual cortex development are dealt with in the Discussion. The following conclusions can be drawn: a) The growing of inand output-MF is completed first. b) The development of the internal connecting systems in layers I and IV begins a little later and is completed by the 5th month. c) The MF in layers II and III appear after the 4th month. Kaes (1907) has also described a continuation of MF growth in man lasting into the twenties.
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 169 (1976), S. 395-403 
    ISSN: 1432-0878
    Schlagwort(e): Taste buds ; Fishes ; Electron microscopy ; Nucleolus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Taste buds occur in the epithelium of the catfish barbel along its entire length. Two major cell types, light and dark cells, occupy the upper two-thirds of the taste bud. A third cell type, the basal cell, lies on the basal lamina and is essentially separated from the light and dark cells by a plexus of unmyelinated nerve fibers. The dark cells have branching processes, both apically and basally whereas the light cells have a single apical process and many basal processes. The apical processes of dark cells contain secretory granules, while the apical processes of light cells contain an abundant agranular endoplasmic reticulum. Light cell nuclei contain bundles of 10 nm filaments, often arranged in the shape of a cup or ring, but nucleoli are rarely seen. It is suggested that this morphology indicates a low degree of RNA synthesis by light cells. The basal cells contain large numbers of vesicles, about 60 nm in diameter, which are sometimes seen in clumps in relation to an adjacent nerve fiber in a configuration resembling a synapse. Curiously, although basal cells present a large surface to the basal lamina, there are no hemidesmosomes. This suggests that the basal cell does not originate from the epidermis.
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 172 (1976), S. 157-169 
    ISSN: 1432-0878
    Schlagwort(e): Placenta (Human) ; Capillaries ; Tight junctions ; Electron microscopy ; Freeze-fracturing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of human placental capillaries was investigated using perfusion fixation and the freeze-fracturing technique. The capillaries have a continuous endothelium especially rich in microfilaments, whereas micropinocytotic vesicles are exceedingly scarce. The endothelial cells are connected by three types of junctions: (1) zonulae occludentes characterized by 2 to 4 focal regions of membrane contact in thin-sectioned specimens and an equal number of ridges on the membrane E-face in freeze-fractured specimens; (2) small gap junctions associated with the zonula occludens. (3) attachment plaques resembling zonulae adhaerentes in their fine structure. Endothelial cells are provided with long, circularly oriented pseudopodial extensions, which may be responsible for intermittent constrictions of the vessel lumen. These findings indicate that diaplacental transport at the level of the fetal capillary is controlled by the cytoplasm of the endothelial cells and probably occurs only to a very limited extent by way of micropinocytotic vesicles.
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 281-288 
    ISSN: 1432-0878
    Schlagwort(e): Striated muscle ; Guinea-pig urethra ; Innervation ; Morphology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Light and electron microscopic techniques have been used to determine the distribution, morphology and innervation of subepithelial striated muscle cells in the wall of the proximal urethra of the male guinea-pig. These cells form a continuous layer, immediately beneath the urethral epithelium extending from the bladder neck to the termination of the ejaculatory ducts into the proximal urethra. They differ from “typical” striated muscle fibres (as seen in the external urethral sphincter) by their small size, rich acetylcholinesterase content and the irregular arrangement of intracellular myofilaments and sarcoplasmic reticulum. In addition, motor end plate regions have not been observed on these striated cells when examined using a light microscopic histochemical technique. The cells are related to acetylcholinesterase positive nerves which run between them in a manner compatible with the occurrence of “en passant” synaptic interactions. Using electron microscopy, axonal varicosities containing small (50 nm diameter) agranular vesicles are encountered 50 nm from the striated cells; membrane specialisations characteristic of motor end plates have not been observed on the cells. The findings are discussed, particularly in relation to the distribution, unusual morphology and innervation of these subepithelial muscle cells.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 65-78 
    ISSN: 1432-0878
    Schlagwort(e): Muscle fibre types ; Axolotl (Ambystoma mexkanum) ; Morphometry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Morphometric analysis by light microscopy of p-phenylene-diamine stained semithin sections of axolotl tail muscle revealed differences in the cross-sectional area of the fibres and in the number of mitochondria and of lipid inclusions per fibre, and indicated the presence of three distinct types of fibres. The tripartition was found to be statistically highly significant. Representative fibres from each group established by light microscopic morphometry were subjected to an ultrastructural morphometric analysis. The volume content of mitochondria amounted to 9.8% of the fibre volume for red, 4.0% for intermediate and 0.8% for white fibres. The myofibrils composed 60%, 70% and 83% in the same fibres. The volume of the sarcotubular system (t-tubuli and sarcoplasmic reticulum) was 2.5% in red, 4.5% in intermediate and 11.7% in white fibres. The three fibre types also demonstrated differences in myofibrillar cross-striation pattern and number of triads. The reliability of the light microscopic morphometry was tested by correlation with EM montages of the representative fibres.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 427-430 
    ISSN: 1432-0878
    Schlagwort(e): Chromatoid body ; Acrosome ; Electron microscopy ; Myxine glutinosa L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Eine vorübergehende enge Beziehung zwischen dem Chromatoiden Körper und dem sich entwickelnden Acrosom wird in jungen Spermatiden von Myxine glutinosa demonstriert.
    Notizen: Summary A transient close relationship between the chromatoid body and the developing acrosome is demonstrated in early spermatids of Myxine glutinosa.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 175 (1976), S. 59-72 
    ISSN: 1432-0878
    Schlagwort(e): Retina ; Xenopus ; Rods ; Cones ; Hemicholinium-3 ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Hemicholinium-3 (HC-3), a drug which prevents synthesis of acetylcholine in neurons, when injected intraperitoneally in doses as low as 2×5 mg/kg produces marked ultrastructural changes and damage in rod but not in cone photoreceptors. In rods it causes a reduction in cytoplasmic back-ground density, swelling of the endoplasmic reticulum, ballooning of the outer membrane of the nucleus, leaching of the nucleoplasm and clumping of the nuclear chromatin. In dark-adapted rods HC-3 produces some loss of cytoplasmic synaptic vesicles but no reduction in numbers of those vesicles which lie adjacent to the synaptic ribbons. In light-adapted rods the drug does not cause such an apparent reduction of synaptic vesicles but does induce a considerable reduction in numbers of vesicles associated with the ribbons. These structural changes are discussed in the light of what is known about the pharmacology of HC-3 and neurotransmitter release from vertebrate photoreceptors.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 175 (1976), S. 369-390 
    ISSN: 1432-0878
    Schlagwort(e): Electron microscopy ; Crustacea ; Synaptic vesicles ; Biogenic amines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The appearance and distribution of dense-core vesicles in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus, were examined using transmission electron microscopy. Following five fixation techniques, three types of dense-core vesicles were identified on the basis of size and morphology. Type-I vesicles are found in a distinct neuronal fiber system that appears to be involved in chemical transmission within the ganglion. Type-II vesicles occur in nerve processes in the ganglion, in major nerve trunks and in the perineural sheath of the nerves and ganglion. Type-III vesicles are present in all neuronal somata of the ganglion. The distinct morphology and location of the three types of vesicles suggest that their functional roles differ. Furthermore, the histochemical, biochemical and physiological data available for the Stomatogastric ganglion indicate that Type-I vesicles may store dopamine.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 170 (1976), S. 89-94 
    ISSN: 1432-0878
    Schlagwort(e): “C” cells ; Endoplasmic reticulum ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Multiple rough endoplasmic cisternae were found in “C” cells of the adult rat, at interphase. They are considered to be normal constituents of “C” cells. Their morphological relation to rough endoplasmic reticulum and their close proximity to mitochondria, Golgi dictyosomes and secretory granules suggest that they may have a role in the secretory activity of this endocrine cell.
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 170 (1976), S. 95-112 
    ISSN: 1432-0878
    Schlagwort(e): Baroreceptors ; Carotid sinus ; Mechanoreceptors ; Electron microscopy ; Fluorescence histochemistry ; Guinea pig, mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A light and electron microscopic study was undertaken on the baroreceptor axon terminals in the carotid sinus of guinea pigs and mice, using serial semithin and thin sections. Together with their enveloping Schwann cells, numerous lanceolate axon terminals are organized into a well-defined discoid end organ, referred to as the ‘baroreceptor unit’. Baroreceptor units measure 100 to 150 μm in diameter and are arranged in a hexagonal pattern. These end organs represent free branched lanceolate mechanoreceptors of complex type (Andres and von Düring, 1973) which belong to the main group of stretch receptors. In the guinea pig the lanceolate terminals enter the media and approach the innermost layers near the intima. In the mouse the terminals are seen to spread in the adventitia and along the medio-adventitial border. Only a few of them penetrate the external elastic layer. Species differences concerning the localization and extent of these visceral mechanoreceptors are discussed, as well as the modified architecture of the sinus wall in the receptor area (‘elastic segment’). Lanceolate terminals form beaded varicosities which are equipped with finger-like or lamellar axoplasmic protrusions. These projections contain a well-differentiated receptor matrix. They are attached to collagen and elastic fibers. The varicosities include densely packed mitochondria, neurotubules, profiles of axoplasmic reticulum, clear and granular vesicles, and striking accumulations of glycogen particles, lamellated bodies and lysosomes. Four types of varicosities are discerned according to their main axoplasmic components. Various types of these varicosities occur within an individual lanceolate terminal. The adrenergic innervation of the carotid sinus was studied by fluorescence histochemistry. In guinea pigs a multilayered wide-meshed plexus of fluorescent fibers occurs in the adventitia where it is closely related to baroreceptor stem fibers. However, adrenergic axons do not enter the media. In mice fluorescent fibers are extremely rare in the adventitia of the carotid sinus.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 170 (1976), S. 435-454 
    ISSN: 1432-0878
    Schlagwort(e): Visual system ; Thalamus ; Axonal sprouting ; Synapse ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The synaptic organization of the pars lateralis portion of the ventral lateral geniculate nucleus is similar to that of other thalamic nuclei. There are four types of synaptic knobs (RL, RS, F1, F2). RL knobs are large and irregularly shaped, contain round synaptic vesicles and make multiple asymmetrical junctions. They are found primarily in “synaptic islands” making contact with gemmules, spines, small dendrites, and other synaptic profiles containing pleiomorphic synaptic vesicles (F2). Smaller RS knobs contain round vesicles and make asymmetrical junctions with the same type of elements as RL knobs, with the exception of the F2 profiles, but are seldom found in synaptic islands. F1 knobs contain flattened synaptic vesicles and form symmetrical junctions with F2 knobs, gemmules, spines, and small-medium dendrites in synaptic islands, throughout the neuropil, and on the proximal dendrites and soma of the largest type of neuron. F2 knobs are irregularly shaped, contain pleiomorphic synaptic vesicles and make symmetrical junctions primarily with gemmules and spines in synaptic islands. They are postsynaptic to RL and F1 knobs. Occipital decortication indicates that cortical terminals are of the RS type. Bilateral enucleation indicates that retinal terminals are of both the RL and RS type. The large amount of geographic overlap of retinal and cortical terminals on gemmules, spines, and small dendrites found in the neuropil outside of synaptic islands logically would maximize axonal sprouting between these two sources.
    Materialart: Digitale Medien
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  • 55
    ISSN: 1432-0878
    Schlagwort(e): Rat posterior pituitary ; Neurophysin-vasopressinergic and neurophysin-oxytocinergic fibres ; Immunocytochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary By means of the unlabeled antibody peroxidase-antiperoxidase (PAP) technique at the electron microscopic level, it was demonstrated that the hormones of the neural lobe of the rat hypophysis are located in separate neurophysin-vasopressinergic and neurophysin-oxytocinergic nerve fibres. These observations confirm the results of our previous immunocytochemical studies at the light microscopic level.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 171 (1976), S. 499-511 
    ISSN: 1432-0878
    Schlagwort(e): Mitochondria ; Hydra ; Crystals ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Intramitochondrial crystals are found in normal Hydra as well as in animals undergoing various conditions (budding, regenerating, eserinetreated, and sexual). They appear in all regions of the animal, but seem to be more prevalent at or near the extremities: hypostome, tentacles and basal disk. They are found in all of the seven basic cell types: interstitial, cnidocyte, nerve, epithelio-muscular, gland, mucous and digestive cells. The chemical nature of the intramitochondrial crystals is unknown and their significance remains speculative.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 171 (1976), S. 513-521 
    ISSN: 1432-0878
    Schlagwort(e): Melanin ; Sclerotin ; Insect cuticle ; Light microscopy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Black cuticles of larvae and pupae from various Lepidoptera were studied by light and electron microscopy. There are striking differences in the representation of black pigmentation, especially at the ultrastructural level. Two types may be described: 1. With the light microscope black melanin-like grana, electron-dense electron microscopically, are found in the distal parts of the exocuticle. This type is demonstrated in larvae of Celerio euphorbiae, Papilio machaon, and Phalera bucephala. 2. With the light microscope a dark homogeneous layer in the distal exocuticle can be recognized, however, electron microscopically no structures correlated with this dark pigment layer. This type of pigmentation was present in pupae of Pieris brassicae and Aglais urticae; in Pieris larvae the dark pigmented layer appeared to be limited to the epicuticle. In Celerio processes of the epidermal cells are involved in transporting precursors to the exocuticle. The conclusion was reached that black pigmentation in cuticles is based on different mechanisms as proposed by structural features. The two likely mechanisms are melanization and sclerotization.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 172 (1976), S. 425-429 
    ISSN: 1432-0878
    Schlagwort(e): Anterior byssus retractor muscle ; Mytilus edulis (Mollusca) ; 5,6-Dihydroxytryptamine ; Serotonin, Dopamine ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Preliminary ultrastructural studies on the effects of 5,6-Dihydroxytryptamine (5,6-DHT) on the anterior byssus retractor muscle (ABRM) of Mytilus show degeneration of 2 types of monoaminergic nerves after 10 days of drug treatment. One type contained large granular vesicles (560–1,680 Å) while the other had small granular vesicles (200–640 Å). These axons may possibly represent serotonergic and dopaminergic nerves, thought to innervate this muscle. Two other types of profiles seemed to be unaffected by the drug. One conforms to cholinergic nerves while the other has a predominance of large opaque vesicles (1,200–2,500 Å). The significance of these findings is discussed in the light of recent observations on the neurotoxic effects of 5,6-DHT on vertebrate and molluscan nerves.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 165 (1976), S. 171-184 
    ISSN: 1432-0878
    Schlagwort(e): Glio-interstitial tissue ; Muscle cells ; Aplysia ; Dorid nudibranchs ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The muscular walls of the buccal mass and the oesophagus of Aplysia rosea and Glossodoris tricolor were studied by electron microscopy. The cytological features of the muscle cells, neuro-muscular junctions and a neuro-glial junction are described. This junction between an axon and a teloglial process, in the oesophagus of Aplysia, possesses all the cytological differentiations of a typical molluscan synapse. Particular attention is drawn to the distribution of the glio-interstitial tissue and the size of the extracellular spaces in these muscular organs. The classification of these muscle into ‘tonic’ and ‘phasic’ types is discussed. From this study and other data, it is concluded that the development of the glio-interstitial tissue in the muscular organs of molluscs is correlated with the size of the extracellular spaces rather than with the type of contraction of the muscle.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 165 (1976), S. 317-325 
    ISSN: 1432-0878
    Schlagwort(e): Exocytosis, endocytosis ; Freeze-etching ; Electron microscopy ; Membrane particles, rosettes ; Neurohypophysis, neurosecretion ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Images have been obtained from freeze-etch replicas of neurohypophyses which are consistent with the view that orderly arranged aggregates of membrane particles occur in regions where fragments of membrane are being added to and taken away from the plasma membrane during secretion. Aggregates of particles included rosette-like and necklace-like patterns similar to those described by other authors at sites of exocytosis and endocytosis.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 165 (1976), S. 455-465 
    ISSN: 1432-0878
    Schlagwort(e): Thyroid gland ; Temperature-dependent changes ; Electron microscopy ; Histochemistry ; Thyroxine, triiodothyronine ; Amphibia, Gymnophiona
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The thyroid gland of the tropical amphibian Chthonerpeton is markedly stimulated when the animal is exposed for two days to relatively high temperatures (36° C). Control animals were kept at 20° C. The stimulated gland exhibits collapsed follicles and a very tall follicular epithelium. At the ultrastructural level the activated epithelial cells were characterized by an increased number of apical microvilli, increased amounts of rough endoplasmic reticulum, an extended Golgi apparatus and a high number of various granular and vesicular inclusions. These differences in histology and fine structure were not paralleled by quantitative results, which were approximately the same in both groups of animals. The values of these determinations were relatively high.
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  • 62
    ISSN: 1432-0878
    Schlagwort(e): Ecdysial gland (crab) ; Regression ; Rhizocephalan parasite ; Absorptive roots ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ecdysial glands (Y organs) of the crab Carcinus maenas regress in the presence of an external parasite, Sacculina carcini. This regression is more or less severe and may lead to complete autolysis. Three gradual stages in this involutionary process are described. In stage I, the gland cells are nearly normal. Nuclei and cytoplasmic organelles remain unchanged, but large vacuoles begin to appear. Stage II corresponds to more or less drastic nuclear pyknosis and cytoplasmic alterations. Myelin figures are large and numerous. Lysosomes and autophagic vacuoles with phosphatase activity are abundant. However, the general cellular architecture remains preserved. Stage III corresponds to irreversible cytolysis; nuclear envelopes and plasma membranes have disappeared. What remains is an accumulation of cellular debris becoming engulfed by circulating hemocytes. Not all of the gland cells of any given Y organ show the same degree of regression; degeneration is asynchronous. Structures seemingly corresponding to absorptive roots of the parasite are seen. Their lumen is coated with microvilli. The putative direct and indirect influences of the rhizocephalan parasite on its host are discussed. Our results on regressing Y organs of parasitized crabs are compared with those on regressing ecdysial glands of insects.
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 166 (1976), S. 315-318 
    ISSN: 1432-0878
    Schlagwort(e): Ciliary rootlets ; Cilium ; Smooth endoplasmic reticulum ; Thymus (Nude mouse) ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In ciliated cells of thymic cysts in Nude mice, ciliary rootlets are constantly and closely related to smooth endoplasmic reticulum and clear vesicles. This special association suggests that this structure does not play only an anchoring role but must be involved in the general metabolism of the cilium.
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 277-287 
    ISSN: 1432-0878
    Schlagwort(e): Proteoglycans ; Odontoblasts, predentin, dentin ; Calcification ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The localization of proteoglycans in the predentin of the rat incisor was investigated by ultrastructural histochemistry. Ruthenium red stained the cell coat of the odontoblasts as well as intracellular vesicles. There was also a staining of the extracellular matrix, but not of collagen fibers in the predentin. Treatment with the enzyme hyaluronidase prior to staining with ruthenium red abolished the staining of the vesicles and the extracellular matrix but not that of the cell coat. Bismuth nitrate and phosphotungstic acid gave similar staining of odontoblast vesicles and extracellular matrix. It is likely that the stained structures contain proteoglycans. The importance of these proteoglycans and their ultrastructural localization are discussed in relation to intracellular transport and the calcification process.
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 361-371 
    ISSN: 1432-0878
    Schlagwort(e): Nucleolar differentiation ; Nassarius reticulatus ; Cleavage ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In Nassarius reticulatus the nuclei and nucleoli undergo important morphological changes from the zygote to the 16-cell stage. In the zygote and in the trefoil (2-cell) and 4-cell stage, several agranular, fibrillar nucleolus-like bodies 1 μm diameter are present in the interphase nucleus. Granular nucleoli first appear at the 8-cell stage. These nucleoli have fibrillar and granular regions. The granular regions are made up predominantly of ribosome-like osmiophilic granules. From the 16 and 32-cell stage onwards, the one or two spherical nucleoli of each nucleus measure 2.5 μm in diameter and show a concentric organization with a very dense central region surrounded by a broad peripheral zone containing numerous granules, possibly of ribonucleoprotein. At the same time the number of ribosome-like particles increase in the karyoplasm and that of ribosomes in the cytoplasm. These findings are surprising because in eggs with radial cleavage, which have been subjected to more detailed analysis, the first granular nucleoli appear after the end of the cleavage, at the blastula or gastrula stage. The early appearance of granular nucleoli which seem to be characteristic of several eggs with spiral cleavage is discussed in connection with biochemical data on RNA-synthesis.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 11-21 
    ISSN: 1432-0878
    Schlagwort(e): Saccus vasculosus ; Teleost (Anguilla anguilla) brain ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of coronet cells of the saccus vasculosus has been studied in specimens of Anguilla anguilla (L.) at different stages of its life cycle. At all the stages observed coronet cells are composed of a basal and an apical part, the latter bearing globules with primary vesicles. In the larva (a marine form) and in the fully metamorphosed small eel at the time of entry into freshwater the narrow lumen and the vesicles within the apical globules are filled with electron-dense material. In forms in which adaptation to freshwater has occurred, the saccus lumen appears expanded, the apical globules are better developed, and the electron-dense material has disappeared. It is suggested that the two situations observed represent different functional states of the organ, in relation to different conditions of environmental salinity.
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 173 (1976), S. 261-269 
    ISSN: 1432-0878
    Schlagwort(e): Cat ; Ciliary body ; ‘False’ transmitters ; Fluorescence histochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ciliary body of the cat was investigated by fluorescence histochemistry and electron microscopy in an attempt to clarify its sympathetic innervation. Subconjunctival doses of 5-hydroxydopamine (5-OHDA) or 6-hydroxydopamine (6-OHDA) were given to establish the precise location of the sympathetic nerve terminals. The distribution of noradrenergic fibers and terminals was shown by fluorescence histochemistry to be sparse in the trabecular meshwork and the anterior portion of the ciliary muscle, but dense in the subepithelial tissue. The small and large dense core vesicles which occur in many nerve endings of the subepithelial tissue adjacent to the pigmented epithelial layer increased in electron density following the administration of 5-OHDA. Many degenerating nerve endings were found in the same region of animals treated with 6-OHDA. In contrast, there were few noradrenergic terminals in the ciliary muscle except for a portion of the smooth muscle which was shown to be dually innervated. The noradrenergic fibers in the subepithelial region and the trabecular meshwork may play an important role in aqueous secretion and outflow.
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 169 (1976), S. 233-245 
    ISSN: 1432-0878
    Schlagwort(e): Isocortex (Man) ; Non-pyramidal cells ; Interneurons ; Lipofuscin pigment ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary With the aid of a newly developed technique for the successive examination of both the Golgi and pigment picture of individual neurons (Braak, 1974a) Braak (1974b) demonstrated that within lamina II and upper lamina III of the human isocortex, heavily pigmented non-pyramidal cells are distributed irregularly and sparsely. The lipofuscin pigment granules serve as excellent internal markers to identify these non-pyramidal cells in ultrathin sections. This favourable circumstance facilitates the study of these interneurons in the electron microscope. The heavily pigmented non-pyramidal cells are small, spherical to ovoid with diameters of about 12–15 μm. One pole of the cell comprising a large cytoplasmic area gives rise to a few dendrites, while the other pole is occupied by the nucleus and in some cases is in close apposition to another nerve cell body. The nucleus is deeply invaginated by the large cytoplasmic area and occasionally displays nuclear inclusions. Among the usual organelles distributed within the large cytoplasmic area the mitochondria with a moderately electron dense matrix are abundant and the coarse lipofuscin pigment granules are the most striking elements. The latter contain densely packed filamentous or tubular material and a single vacuole. The perikaryon rarely receives more than 3 type I and type II synapses per section per cell, whereas the dendrites receive numerous synapses of both type I and type II. Within the apposition zone to another nerve cell body (which in no case is a heavily pigmented non-pyramidal cell) puncta adhaerentia occur and also contacts in which the cleft of 8 nm is intersected by a dense stratum. Some of the ultrastructural findings are summarized in the schematic drawing of Figure 15.
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 173 (1976), S. 451-460 
    ISSN: 1432-0878
    Schlagwort(e): Cardiac sarcomeres ; Tmetonyx cicada (Crustacea) ; T-tubules ; Sarcoplasmic reticulum ; Couplings ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The membrane systems of the cardiac muscle cell of the amphipod Tmetonyx cicada (O. Fabricius) are described. The sarcolemma invaginates and forms a transverse network of tubules at the level of the Z band. Narrow longitudinal tubules branch from the network and connect to another transverse network of tubules at the H band level, where dyadic and triadic junctions are formed with the sarcoplasmic reticulum. Adjacent myofibrils are normally separated by a well developed double layer of the sarcoplasmic reticulum. In areas where the myofibrils closely approach the outer sarcolemma, peripheral couplings have been found at the level of the H band.
    Materialart: Digitale Medien
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 99-108 
    ISSN: 1432-0878
    Schlagwort(e): Axonal spheroids ; Spinal cord ; Rabbit ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Within the gray matter and the white matter of the spinal cord of apparently healthy rabbits, myelinated and unmyelinated axonal swellings, so called “axonal spheroids”, occur. Most of the spheroids contain mitochondria, dense bodies, vesicles and fragments of the tubular or smooth endoplasmic reticulum. In myelinated spheroids the process of swelling is effected by slippage of the myelin leaflets. At the periphery of the unmyelinated parts of the spheroids, synapses are regularly found. The presynaptic terminal bouton is formed by the spheroid. A few myelinated and unmyelinated spheroids are packed with fine granular material while mitochondria are lacking. The axonal spheroids may represent a physiological, perhaps age dependent phenomenon.
    Materialart: Digitale Medien
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 527-536 
    ISSN: 1432-0878
    Schlagwort(e): Endometrium ; Innervation ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The innervation of the endometrium of rabbit, rat, mink, mongoose and pig has been investigated electron microscopically. Large bundles of nerve fibers can be observed in the connective tissue spaces within the basal layer of the endometrium. Unmyelinated nerve fibers enter the lamina functionalis, terminal nerve fibers penetrate the basal lamina and make contact with the glandular and the cavum epithelial cells. The terminal axons contain abundant synaptic vesicles, dense core vesicles and mitochondria. To date, no specialized presynaptic or postsynaptic membranes have been found.
    Materialart: Digitale Medien
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 171 (1976), S. 285-296 
    ISSN: 1432-0878
    Schlagwort(e): Prostate ; Rat ; Castration ; Nuclear alterations ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of the nuclei of epithelial cells of the dorsal lobe of the rat prostate were studied 2, 3, 5, 7 and 21 days after castration. The nucleolus appears to undergo a progressive disorganisation with partial fragmentation and dispersion of its normal components. Changes in the nucleoplasm were primarily reflected by a condensation of chromatin, particularly along the nuclear membrane and adjacent to the nucleolus. Later, different types of intranuclear inclusions were observed. After 21 days, the nuclei were characterized by an irregular outline with large indentation. Within the nucleoplasm aggregates of coarse granular chromatin were found. No cell necrosis was observed, indicating that androgen deprivation results in a remodeling of the cell to a less active state with marked cellular alterations and cessation of secretion, but apparently with some of their basic functions still intact. Injections of testosterone completely reverse the castrated-induced alterations. The changes observed are assumed to be due to the withdrawal of the androgenic stimulus, with a direct influence on the secretory function of the cell. The findings support the view that the stimulating secretory effect of androgen is mediated via an intranuclear androgen receptor, probably located in the nucleolus-associated-chromatin. It is also proposed that the secretory function of the epithelial cells of the prostatic complex, initiated by androgens, may be regulated by an intranuclear secretory center.
    Materialart: Digitale Medien
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 171 (1976), S. 375-379 
    ISSN: 1432-0878
    Schlagwort(e): Corpus luteum ; Autografts ; Rat ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The rat ovary has been transplanted successfully to subcutaneous tissue areas by several investigators. Light microscopy has revealed that corpora lutea in ovarian autografts are formed by luteinization of intact follicles and contain entrapped ova. In the present study, corpora lutea from autografted ovaries in castrate rats were obtained at metestrus and examined electron microscopically to determine whether their cellular morphology correlated with the normal progesterone levels in these animals. Cellular features usually accepted as regressive were apparent. The findings suggest either structural luteolysis is occurring before functional luteolysis or that the adrenal has increased steroidogenic activity in the castrate with ovarian autografts to account for the normal progesterone levels.
    Materialart: Digitale Medien
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 171 (1976), S. 381-387 
    ISSN: 1432-0878
    Schlagwort(e): Melanophores ; Teleost ; Nerve fibres ; en passant synapses ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Contacts between small unmyelinated nerve fibres and dermal melanophores of the angelfish, Pterophyllum scalare, exhibit several features characteristic of synapses, including small synaptic vesicles and dense core vesicles, a narrow synaptic cleft, electron-dense material at the postsynaptic membrane (cell membrane of the melanophore) and, occasionally, presynaptic densities. An analysis of serial thin sections shows that the synapses described here represent varicosities of an otherwise more or less straight nerve fibre. A single axon thereby may form several en passant synapses with a single melanophore. It is suggested that the synaptic contacts described here not only represent sites of transmitter release but also play a role as sites of firm attachment between nerves and melanophores which guarantee a stable arrangement of nerve fibres and melanophores. Supported by the Deutsche Forschungsgemeinschaft
    Materialart: Digitale Medien
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 171 (1976), S. 425-435 
    ISSN: 1432-0878
    Schlagwort(e): Cholecystokinin-pancreozymin (CCK-PZ) ; Glycoprotein secretion ; Mouse gallbladder ; Exo-endocytosis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Structural changes in the gallbladder epithelial cells of the mouse were studied following in vivo and in vitro stimulation of the gallbladder with the gastrointestinal hormone cholecystokinin-pancreozymin (CCK-PZ). Signs of increased secretory activity were observed within the first 2–3 min after hormone administration. At the ultrastructural level, best visualized with the PA-CrA-silver technique, granule discharge was observed, as was an overall increase in size of the granules. After prolonged in vitro incubation or repeated in vivo stimulation, there was an almost total depletion of secretory granules. This phenomenon is accompanied by an enhanced uptake of extracellular thorium dioxide by endocytotic vesicles at the apical cell surface. An exocytosisendocytosis coupling mechanism may be important for membrane conservation in the gallbladder epithelial cells. The findings establish that the hormone CCK-PZ stimulates the secretion of glycoproteins from the mouse gallbladder epithelium.
    Materialart: Digitale Medien
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 171 (1976), S. 543-549 
    ISSN: 1432-0878
    Schlagwort(e): Shell ; Centropyxis hirsuta ; Manganese ; Shell structure ; X-ray diffraction ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The proteinaceous shells of Centropyxis hirsuta contain a relatively high concentration of manganese in an amorphous state. The concentrations of manganese fill the alveoli which are characteristic of the shell structure. Observations based on cultured animals and subsequently examined by X-ray diffraction, a solid state energy dispersive X-ray analyser, and an analytical electron microscope, lead to the conclusions that manganese is selectively absorbed by Centropyxis hirsuta and deposited in the shell.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 172 (1976), S. 59-79 
    ISSN: 1432-0878
    Schlagwort(e): Aorta (rat) ; Smooth muscle cells ; Elastin ; Transplantation ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Smooth muscle cells were enzymatically isolated from the tunica media of the aorta of 5-day-old rats. Following in vitro exposure to colloidal thorium dioxide particles the cells displayed numerous lysosomes filled with these particles. Intramuscular injection of isolated cells into the tongues of young rats of the same strain, resulted in the formation by both freshly isolated and thorium dioxide-labeled cells of a characteristic tissue similar to that found in the intact aortic wall. Thus, the transplants consisted of typical smooth muscle cells surrounded by an extracellular matrix consisting of a microfibrillar network, patches and fibers of elastin, collagen fibrils and small polygonal granules believed to represent proteoglycans. This system can be used for experimental studies on the production of extracellular matrix components and on other functions of arterial smooth muscle cells growing outside the vascular wall. The technical assistance of Ms. Karin Blomgren and the secretarial assistance of Ms. Inger Åhrén are gratefully acknowledged
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 172 (1976), S. 81-91 
    ISSN: 1432-0878
    Schlagwort(e): Skin glands ; Innervation ; Electron microscopy ; Frog
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A comparative study was undertaken on the innervation of mucous and granular glands in frog skin. Results obtained by the Falck-Hillarp fluorescence technique and cholinesterase staining indicated that both types of glands receive exclusively adrenergic innervation. Electron microscopy was used to investigate the innervation pattern at the ultrastructural level. The distribution of nerve terminals was found to differ in the two types of glands. In the mucous gland, terminals were found at a distance of about 0.5 μm from the basement membrane but never within the gland parenchyma. In the granular gland, the terminals were located between smooth muscle cells and also in direct contact with the secretory epithelium but never outside the basement membrane.
    Materialart: Digitale Medien
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 172 (1976), S. 529-540 
    ISSN: 1432-0878
    Schlagwort(e): Unicellular hatching gland ; Salmonid fish ; Hatching ; Secretory granule ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The unicellular hatching glands (UHGs) of four species of salmonid fish, Salmo gairdneri, Salmo trutta, Salvelinus fontinalis and Salvelinus pluvius were studied by light and electron microscopy. The UHGs are distributed on the epidermis of head and yolk sac, and on the epithelium of the mouth and gills. Since these cells are large and include dilated cisternae of the endoplasmic reticulum from the primitive to the mature stages they are conspicuous. Around the Golgi complexes, there are consecutive figures showing synthesis of secretory granules with close relationships to the Golgi vesicles. The secretory granules grow in size and vary in density during maturation; some have enclosed cytoplasmic structures. At the hatching stage, they are discharged with some cytoplasmic structures from the UHG which is located in the superficial layer of epithelium. After exhaustion of the secretory granules, the remainder of the contents of UHGs is liberated.
    Materialart: Digitale Medien
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 165 (1976), S. 141-156 
    ISSN: 1432-0878
    Schlagwort(e): Basilar papilla ; Lizard (Calotes versicolor) ; Innervation ; Sensory cells ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The basilar papilla of the lizard Calotes versicolor contains about 225 sensory cells. These are of two types: the short-haired type A cells in the ventral (apical) part of the organ, and the type B cells with long hair bundles, in the dorsal (basal) part of the organ. The type A cells are unidirectionally oriented and are covered by a tectorial membrane while the type B cells lack a covering structure and their hair bundles are oriented bidirectionally. Apart from those differences, the type A and type B cells are similar. They are columnar, and display the features common to most sensory cells in inner ear epithelia. The sensory cells are separated by supporting cells, which have long slender processes that keep the sensory cells apart. Close to the surface of the basilar papilla a “terminal bar” of specialized junctions interlocks adjacent cells. Below this, adjacent supporting cells are linked by an occluding junction. The cochlear nerve enters from the medial (neural) aspect. The fibres of the nerve lose their myelin sheaths as they enter the basilar papilla. Each sensory cell is associated with several nerve endings. All the nerves identified were afferent. Marked variations were seen between nerve endings in the basilar papilla, but no morphological equivalents of any functional differences were observed.
    Materialart: Digitale Medien
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 165 (1976), S. 467-475 
    ISSN: 1432-0878
    Schlagwort(e): Thyroid gland ; Temperature-dependent changes ; Thyroxine ; Electron microscopy ; Amphibia, Urodela
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The influence of temperature on the thyroid gland of the Caucasian salamander, Mertensiella caucasica has been studied (1) with the light- and electron microscopes, (2) with enzyme histochemical and quantitative methods. Animals which had been kept for years at 16° C were exposed for 48 hrs to 4° C or 27° C. At 4° C the follicular epithelium consisted of cuboidal cells with well-developed rough ER, occasional distended cisternae of the rough endoplasmic reticulum (ER) filling most of the cytoplasm, a relatively small Golgi apparatus and numerous round or oval shaped lysosomes. In animals kept at 27° C the follicular wall was composed of markedly taller epithelial cells, the apices of which bulged into the follicular lumen. Compared to the animals at 4° C, there appeared to be a decrease in the rough ER. The Golgi apparatus did not exhibit clear differences. The lysosomes increased in number and showed various shapes among which elongated ones with pointed ends were particularly striking. In the apical cytoplasm colloid droplets appeared indicating hormone release. The apical microvilli increased in number. The measurements of total T4 have shown that the hormone level in animals kept at 27° C was about twice as high as in animals kept at 4° C.
    Materialart: Digitale Medien
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 165 (1976), S. 545-553 
    ISSN: 1432-0878
    Schlagwort(e): Neurophysine-containing vesicles ; Neurosecretory system ; Vertebrates ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A new method described in the present paper allows identification of neurophysine-containing (NP) vesicles of the magnocellular neurosecretory system of vertebrates. After oxidation of ultrathin sections, the content of NP vesicles can be dissolved specifically in an alkaline medium. This procedure marks NP vesicles selectively in all portions of the classical neurosecretory system.
    Materialart: Digitale Medien
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  • 83
    ISSN: 1432-0878
    Schlagwort(e): Neurosecretory granules ; Morphometric classification ; Neurohypophysis ; Hagfish, Eptatretus burgeri ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Neurosecretory axons in the neurohypophysis of the hagfish, Eptatretus burgeri, were statistically classified into six types according to the size of secretory granules. These types are comparable with those in higher vertebrates. The concentration of each axon type is different in three regions: anterior dorsal wall, posterior dorsal wall, and ventral wall. The regional differences of the hagfish neurohypophysis are discussed in relation to the regional differentiation of the tetrapod neurohypophysis into the median eminence and the pars nervosa.
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 166 (1976), S. 185-200 
    ISSN: 1432-0878
    Schlagwort(e): Hypophysis, Pars distalis ; Cyclostomes, Actinopterygians ; Nongranulated cells ; Function ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The structure of the nongranulated cells in the sea lamprey adenohypophysis and similar cells of the rostral pars distalis in a number of actinopterygian fishes was examined with the aim of determining the role(s) of these cells in pituitary function. A number of possible roles are proposed for the nongranulated cells. In salmonids and Amia calva the cells may be involved in the active movement of material into or from the follicle lumina. The structure of the nongranulated cells in in vitro cultured and in in vivo transplanted trout rostral pars distalis also suggests a phagocytotic role for these cells. In teleosts with a non-follicular rostral pars distalis the nongranulated cells appear to play roles in the release of granules from the prolactin cells and in the subsequent dispersal of the hormone (and/or carrier substance) into the peripheral circulation.
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 166 (1976), S. 219-234 
    ISSN: 1432-0878
    Schlagwort(e): Electron microscopy ; Byssus ; Collagen ; Mytilus galloprovincialis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the byssus of Mytilus galloprovincialis was analysed by transmission electron microscopy in thin sections of either embedded or frozen samples. All parts of the byssus (stem core laminae, stem outer laminae, threads proximal and distal parts) appear to be formed by the same basic filamentous components organized in different ways at the submicroscopic level and embedded in a variable quantity of matrix. The filaments appear to consist of a central electron-lucent zone (3 nm in diameter), surrounded by an electron-dense rim (total diameter 7 nm). The matrix has a granular or microfilamentous structure. The stem and the threads differ greatly in their submicroscopic organization, but their basic constituents (filaments and matrix) are similar. Peculiar filamentous banded elements (FBE) were found mainly in the stem outer laminae. A relation between the ultrastructure and mechanical properties of the different parts of the byssus was established. The presence of collagen is discussed; since no morphological evidence of any of the known forms of collagen organization was revealed by electron microscopy, it is suggested that byssus collagen may be localized in the matrix and in the FBE.
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 166 (1976), S. 235-240 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary ; Pars distalis ; Chromophobe ; Reptile ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Chromophobes of the pars distalis in young Chelydra serpentina have sparse cytoplasm with no specific granules; however, many cytoplasmic filaments are present. The chromophobes are connected to the other cell types by desmosomes, while different types of junctional specializations occur between adjacent chromophobes. Cytoplasmic filaments traverse the cytoplasm in a random manner and terminate on both the junctional complexes and the nuclear envelope. It is proposed that, in addition to providing a structural framework, the chromophobes may be involved in integrating cellular responses of the parenchyma to changes in the endocrine milieu.
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 547-561 
    ISSN: 1432-0878
    Schlagwort(e): Retinohypothalamic projection (mouse) ; Suprachiasmatic nucleus ; Electron microscopy ; Cobalt chloride-iontophoresis technique
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The problem of the direct retinohypothalamic projection in mammals (Moore, 1973) was reinvestigated in the laboratory mouse by electron microscopy and cobalt chloride-iontophoresis. The time-course of the axonal degeneration in the suprachiasmatic nucleus was studied 3, 6 and 12 h, 1, 2, 4, 6, 9 and 12 days after unilateral retinectomy. Specificity of the degenerative changes was controlled by investigation of the superficial layers of the superior colliculus. The ratio of crossed to uncrossed optic fibers could be determined by counting degenerating structures (axons and terminals) in the optic chiasma and the ipsilateral and contralateral areas of the optic tract, the suprachiasmatic nucleus, and the superior colliculus. The number of degenerating axons in the suprachiasmatic nucleus showed a maximum one day after unilateral retinectomy and was, at all stages studied, two to three times higher in the contralateral than in the ipsilateral nuclear area. In the optic tract and in the superior colliculus the number of degenerating profiles was three times higher in the contralateral than in the ipsilateral area. Retinohypothalamic connections and crossing pattern of retinal fibers were studied light microscopically using impregnation with cobalt sulfide in whole mounts of brains. Most of the optic fibers in the laboratory mouse are crossed (70–80%). A bundle of predominantly crossed optic fibers runs to the suprachiasmatic nucleus.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 33-43 
    ISSN: 1432-0878
    Schlagwort(e): Human fetal pancreas ; Endocrine cells ; Argyrophil reactions ; Light microscopy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The endocrine cells in the pancreas of five human fetuses with gestational ages of 18–20 weeks were examined by light and electron microscopy with special regard to argyrophil reactions. B-cells and typical A and D-cells were easily identified electron microscopically on the basis of their typical secretory granules. In the Grimelius argyrophil silver stain, a concentration of silver grains over the less electron dense peripheral mantle of the A-cell secretory granules was observed by electron microscopy. In the Hellerström and Hellman modification of the argyrophil Davenport alcoholic silver stain, silver grains were concentrated over the internal structures of the D-cell secretory granules. With this stain an accumulation of silver grains was also seen at the surface of the A-cell secretory granules. The argyrophil reaction of the A-granules was less pronounced than in the D-cells. In addition to B-cells and A- and D-cells, two other types of endocrine cell were observed by electron microscopy. These cells were argyrophil with the silver impregnation method of Grimelius. The electron microscopic findings at least partly explain the frequent overlapping between the two staining methods observed at the light microscope level.
    Materialart: Digitale Medien
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 89-99 
    ISSN: 1432-0878
    Schlagwort(e): Osteoclast ; Protein export ; Lysosome ; Electron microscopy ; Autoradiography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The present electron microscopic autoradiographic study includes a quantitative analysis of osteoclasts in vitro using tritiated leucin as a protein tracer. A significant increase in the grain density over the ruffled border and the underlying resorption zone was demonstrated two hours post pulse whereas the grain density of the remaining cytoplasm was relatively constant. This indicates a transport of newly synthesized protein from the osteoclast to the extracellular resorption zone. Earlier histochemical and biochemical experiments suggest that the exported protein may represent lysosomal enzymes to be used in the extracellular bone degradation.
    Materialart: Digitale Medien
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 133-140 
    ISSN: 1432-0878
    Schlagwort(e): Thyroid gland ; Follicle cell ; Junctional complex ; Freeze fracturing ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Zonulae occludentes, gap junctions and desmosomes have been demonstrated in replicas of freeze-fractured follicular cells of normal human and rabbit thyroid glands. The zonulae occludentes between the human follicular cells are composed of two to eight strands, which completely separate the intercellular space from the follicular lumen. Four to twelve or more strands are visible between the follicular cells of the rabbit thyroid gland. In the meshes of the zonulae occludentes as well as below them, gap junctions are present. They are numerous on the fracture faces of the human follicular cell membranes, but infrequent in those of the rabbit. Aggregates of particles related to desmosomes are found in the deeper meshes of the zonulae occludentes or close to them.
    Materialart: Digitale Medien
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  • 91
    ISSN: 1432-0878
    Schlagwort(e): Muscle ; Diabetes mellitus ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of fast-twitch-oxidative-glycolytic (FOG), fasttwitch-glycolytic (FG) and slow-twitch-oxidative (SO) fibers in plantaris and soleus muscles of normal and streptozotocin-diabetic rats was studied. In the diabetic animals, the mitochondria of FOG and SO fibers showed a loss of cristae and an increase in electron-dense granules. There was also an increased number of lipid droplets in close proximity to the mitochondria and the nuclei, and a separation of individual muscle nuclei to form satellite cells. Higher incidences of surface projections and sarcoplasmic splittings at the nuclear region were noticed in SO fibers. The FG fibers showed some disorientation of the T-tubular system. It is concluded that streptozotocin-diabetes has differential effects on the fine structure of the three fiber types of rat skeletal muscle.
    Materialart: Digitale Medien
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 166 (1976), S. 489-496 
    ISSN: 1432-0878
    Schlagwort(e): Cerebellar cortex (Rhesus monkey, cat) ; Supraganglionic plexus ; Myelinated parallel fibers ; Regional distribution ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the cerebellar cortex of the Rhesus monkey and the cat, the supraganglionic plexus in the molecular layer exhibits regional differences. The plexus is very well developed in the vermal parts of the anterior lobe, but only poorly developed in the nodulofloccular lobe. Most of the fibers of this plexus are myelinated parallel fibers, which synapse in the typical manner with dendritic thorns of Purkinje cells. Only very few fibers of this plexus are recurrent collaterals of Purkinje cells. Their distribution throughout the cerebellar cortex does not display regional differences. These findings agree with physiological data on the disinhibition of Purkinje cells in different parts of the cerebellar cortex.
    Materialart: Digitale Medien
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 166 (1976), S. 521-530 
    ISSN: 1432-0878
    Schlagwort(e): Ependyma ; Fish ; Third ventricle ; Hypothalamus ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ependyma lining the lateral recess of the third ventricle of the teleost inferior lobe has been studied by light and electron microscopy, including Golgi impregnation methods. As many as five different cell types appear to line the ventricle, but some of these may be similar cells in different stages of activity. One cell type contains small dense-cored vesicles and appears to have processes extending into deeper portions of the lobe. Golgi preparations reveal subependymal cells with apical processes extending to the ventricle and basal extensions which may reach the pial surface. The present observations are discussed in relation to similar studies in other fishes, amphibians and mammals. Possible functions for the various cells observed are suggested.
    Materialart: Digitale Medien
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 173 (1976), S. 167-171 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland ; Annulate lamellae ; Electron microscopy ; Teleost
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A multilamellate body (MLB), bearing close resemblance to an array of annulate lamellae, has been observed in several adenohypophysial cell types of the teleost, Hemihaplochromis philander. In longitudinal section, each MLB comprises a ladder-like row of 12–50 sausage-shaped profiles, termed lamellae. A few lamellae in each section show connections with the endoplasmic reticulum. Apposition of paired lamellar membranes at regularly spaced intervals results in a beaded appearance, whereby sites of membrane apposition are probable pore sites. The MLB differs from annulate lamellae in having poorly developed pores and closer packing of lamellae. It is suggested that the MLBs described here, may represent annulate lamellae at a stage of development or break-down when pores are incomplete.
    Materialart: Digitale Medien
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 173 (1976), S. 287-308 
    ISSN: 1432-0878
    Schlagwort(e): Synaptic complexes ; First visual ganglion ; Electron microscopy ; Fly, Musca domestica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the lamina ganglionaris, the first optic ganglion of the fly, the inventory of cell types as well as the patterns of their connections are well known from light microscopic investigations. Even the synaptic contacts are known with relative completeness. However, the structural details visible on electron micrographs are very difficult to interpret in functional terms. This paper concentrates on two aspects: 1) the synaptic complex between a retinula cell axon and four postsynaptic elements, arranged in a constant elongated array (it is suggested that all synapses in which the retinula cell is presynaptic are of this kind), and 2) the “gnarl” complex in which a presynaptic specialization in one neuron is separated from another neuron by a complicated glial invagination. The participation of glia at postsynaptic sites seems to be quite common in this ganglion. Occasionally it seems that a glia cell is the only postsynaptic partner facing a presynaptic specialization within a neuron.
    Materialart: Digitale Medien
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 173 (1976), S. 437-449 
    ISSN: 1432-0878
    Schlagwort(e): Graafian follicle (rabbit) ; Ovulation ; Ovary surface epithelium ; Lysosomes ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Rabbit ovarian preovulatory follicles and in particular the overlying surface epithelium were studied by morphological and ultrahistochemical means at different times after mating. By light microscopy an increase of cytoplasmic granules was found in the surface epithelium at the follicle apex 4 h after mating. The granules increased in amount and showed maximal accumulation 8–9 h after mating. They then disappeared at the same time as the connective tissue elements in the underlying tunica albuginea and theca externa disintegrated. Transmission electron microscopy showed that the membrane-bounded granules or dense bodies fused with one another and by 8 h after mating they often changed character and appeared more electron lucent. Furthermore, open communications were found between altered granules and vacuoles and between vacuoles and the extracellular space below the epithelium. Acid phosphatase reaction product was localized to the granules and Golgi cisternae. Not all the dense bodies were enzyme positive. At later stages, close to the time of follicle rupture, the epithelial cells were attenuated and thin, with only a few granules. By scanning electron microscopy it was found that the epithelial cells at the follicle apex increased in size approaching the time of follicle rupture and that their microvilli decreased in number and in size. At 8 h and later, the contours of intracellular granules could be visualized. The results of this study were similar to those found when rabbits were induced to ovulate by HCG-stimulation. This further strengthens the hypothesis that the surface epithelium contributes proteolytic enzymes which help to disintegrate the follicle apex prior to rupture.
    Materialart: Digitale Medien
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  • 97
    ISSN: 1432-0878
    Schlagwort(e): Amphibian posterior pituitary ; Vasotocinergic and mesotocinergic fibres ; Immunocytochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Using the unlabeled antibody peroxidase-antiperoxidase (PAP) technique at the electron microscopic level, it was demonstrated that the hormones of the posterior pituitary of Rana temporaria are located in separate vasotocinergic and mesotocinergic nerve fibres. This observation confirms the results of our previous immunocytochemical studies at the light microscopic level.
    Materialart: Digitale Medien
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 55-67 
    ISSN: 1432-0878
    Schlagwort(e): Septate junctions ; Polychaeta ; Fine structure ; Cell junctions ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Epidermal septate junctions of Nereis sp. and Cirriformia sp. fixed with OsO4 or glutaraldehyde/OsO4 display variable structure in electron micrographs. In transverse section the septa are often indistinct and obscured by opaque material that fills the junctional cleft. Septa (spaced at 180–280 Å) are more clearly defined in slightly oblique transverse section; they exhibit an electron lucent center and appear to be linked by arms. En face views of the junction show a honeycomb pattern. Cytoplasmic faces of junctional membranes are backed with plaques opposite the septa. Lanthanum used as a tracer delineates junctional structure in negative contrast. In transverse section a chain-like lattice is present in the junctional cleft. En face views show parallel rows of pleated elements often linked by arms into honeycomb arrays. Oblique sections demonstrate that these pleated elements are continuous with the chain-like lattice seen in transverse sections. Lanthanum does not pass entirely through the junction. Lanthanum reveals that the septa have a very intricate substructure, but it is difficult to visualize the architecture that could generate the various images presented by these junctions when seen in different orientations. However, it is clear that these junctions possess some features that are diagnostic of several supposedly different types of septate junctions in invertebrates.
    Materialart: Digitale Medien
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 83-97 
    ISSN: 1432-0878
    Schlagwort(e): 6-hydroxydopamine ; Extraneuronal effects ; Rat ; Adrenal ; Tissue culture ; Electron microscopy ; Microspectrofluorimetry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of various concentrations of 6-hydroxydopamine (6OHDA) on rat adrenocortical cells in tissue culture were studied with phase contrast and electron microscopy. With 40 mg/l of 6-OHDA the first signs of alteration as revealed by microcinematography appeared in isolated cortical cells as early as 15 min after addition of the drug. There was a cessation of movement of cell organelles and an immobilisation of membrane undulations followed by the development of dark inclusion bodies. The cells underwent increasing shrinkage and collapsed by 11/2 h. Chromaffin cells were not affected until 45 min after exposure to the drug and neurons were the most resistant population. However 61/2 h after application of the drug most cells in the culture were dead. 6-OHDA applied in different doses and to adrenal expiants did not alter the sequence of events. Ultrastructurally cortex cells underwent damage along two lines: they either showed lytic changes or developed various types of dense bodies before reaching the lytic stage. Treatment of cortical cells with 40 mg/l 5-or 6-OHDA followed by exposure to buffered 2% glyoxylic acid and heat did not produce a fluorescence within the cells. Microspectrofluorimetry on amine models with noradrenaline, 5- and 6-OHDA revealed that neither 5-nor 6-OHDA are capable to form a fluorophore with glyoxylic acid.
    Materialart: Digitale Medien
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 247-259 
    ISSN: 1432-0878
    Schlagwort(e): Tendons ; Connective tissue ; Collagen ; Human ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A variety of human tendons have been studied at the electron microscope level. The fibers of these tendons are composed of collagen fibrils that average 1,750 Å and 600 Å in diameter. A third population that measures 100 Å in diameter may represent immature collagen or filaments that are incorporated into tendon elastic fibers. The larger collagen fibrils vary in ratio with respect to one another, and are connected by interfibrillar bridges which in some cases appear to extend through the substance of the fibril. The collagen fibrils of the paratenon are less-well organized than those of the tendon proper and average 600 Å in diameter. Tendons that exhibit the property of lateral stretch (plantaris and palmaris) were compared at the ultrastructural level with tendons that do not have this property. No differences between the two tendon types could be determined in normal or spread preparations, indicating that the differences in physical characteristics are a result of fiber rather than fibril organization.
    Materialart: Digitale Medien
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