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  • 2020-2023
  • 1990-1994  (70)
  • 1980-1984  (139)
  • 1975-1979  (211)
  • 1992  (70)
  • 1982  (60)
  • 1981  (79)
  • 1979  (100)
  • 1975  (111)
  • Electron microscopy  (420)
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Materialart
Erscheinungszeitraum
  • 2020-2023
  • 1990-1994  (70)
  • 1980-1984  (139)
  • 1975-1979  (211)
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Cell populations in the lesion of human cutaneous leishmaniasis: A light microscopical, immunohistochemical and ultrastructural study (1992)
    Springer
    Virchows Archiv 421 (1992), S. 239-247 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Human cutaneous leishmaniasis ; Skin ; Immunohistochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary To characterize the in situ cellular immune response in localized cutaneous leishmaniasis (LCL), the authors studied frozen skin biopsies from 50 patients with LCL due toLeishmania braziliensis guyanensis. A panel of 31 monoclonal antibodies was used, which defined the number and distribution of inflammatory cell subsets. Skin inflammatory infiltrates were composed of T cells (with a local CD4/CD8 ratio of 1.05±0.7 vs 1.48±0.3 in peripheral blood), macrophages and a smaller number of B cells, natural killer cells and granulocytes. Most of the T cells expressed activation markers (interleukin-2 and transferrin receptors, HLA-DR+) and an increase in T-cell-receptorγδ expression was noted. Analysis of the CD4+ subpopulations with newly available reagents showed that helper T cells (CD4+CD45RO+) exceeded the suppressor/inducer subset (CD4+CD45RA+) by 1.4∶1. There were no differences between local immune variables from patients with primary infection (45 patients) and those with recurrence (5). In 7 patients, biopsies were analysed before and 1 month after specific treatment, and did not show significant differences except for a small increase of dermal CD1a+ (Langerhans) cells/mm2. The observed pattern of cellular skin infiltration suggests an immune-mediated tissue injury including T-cell-mediated cytotoxicity and delayed hypersensitivity reactions in addition to direct parasitic action.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01611181
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  • 2
    Digitale Medien
    Digitale Medien
    The glomerular mesangium: capillary support function and its failure under experimental conditions (1992)
    Springer
    Journal of molecular medicine 70 (1992), S. 843-856 
    Details
    ISSN: 1432-1440
    Schlagwort(e): Kidney ; Glomerulus ; Mesangium ; Mesangial failure ; Electron microscopy ; Animal models
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We present a structural analysis of the ability of the biomechanical unit consisting of mesangium and glomerular basement membrane to maintain normal capillary architecture in the face of mechanical challenges due to high intraglomerular pressures. Capillary support function may be considered in terms of the stabilization of local form (development of wall tension against capillary dilation) and global form (centripetal fixation of capillary loops to maintain higher order form). The pathologic consequences of the loss of this support are illustrated by way of experimental models of mechanical mesangial failure. Such failure may express itself as mesangial widening, increased transmesangial macromolecule “traffic,” ballooning of capillary segments, and unfolding of capillary loops. Mechanisms are described by which these structural changes may lead to segmental glomerular sclerosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00180755
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  • 3
    Digitale Medien
    Digitale Medien
    A unique case of naturally occurring mummification of human brain tissue (1992)
    Springer
    International journal of legal medicine 105 (1992), S. 173-175 
    Details
    ISSN: 1437-1596
    Schlagwort(e): Human brain tissue ; Natural mummification ; Histology ; Histochemistry ; Electron microscopy ; Elemetal analysis ; Gehirn ; Mensch ; Naturaliche Mumifikation ; Histologie ; Histochemie ; Elektronenmikroskopie ; Atmospektralanalyse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Rechtswissenschaft
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei Ausgrabungen in Bulgarien wurden Schädel und Knochen von 39 Individuen im Alter zwischen 35 und 60 Jahren, die vor ca. 45–50 Jahren begraben wurden, gefunden. Bei der nachfolgenden gerichtsmedizinischen Experitse wurden in zwei intakten Schädeln und zwischen den Knochen anderer Schädel sieben harte Gebilde (zwei ganze und fünf Fragmente), die wie geschrumpfte menschliche Gehirne aussahen, identifiziert. Entsprechende Proben von diesem Material wurden für 3–4 Tage mit 15% wässriger Lösung von Glycerol weicher gemacht und danach lichtmikroskopisch und elektronenmikroskopisch untersucht. An entsprechenden Stückchen von frischem menschlichem Gehirn und den gefundenen Proben wurde eine Atomspektral-analyse zur Bestimmung des chemischen Bestandes an Elementen durchgeführt. Die komplexe Untersuchung des Materials ergab, daß es sich bei diesem Fund um einen Sonderfall von natürlich mumifizierten menschlichen Gehirnen handelt, die durch sonderbare Bedingungen nur im Schädel der begrabenen Individuen entstanden sind.
    Notizen: Summary When skulls and bones were exhumed from a mass grave in Bulgaria and subjected to medicolegal examination they were found to originate from 39 humans aged 36–60 years old who had been buried approximately 45–50 years ago. Solid structures which strongly resembled shrunken human brain tissue were found inside 2 intact skulls. Among other bones 5 similar structures were found one of which was an almost entirely preserved human brain, and the others were fragments from different regions of the human brain. Samples of these structures were immersed in 15% aqueous glycerol solution to soften and were examined by light and electron microscopy. Sampels of this material and of fresh human brain were subjected to elementary atomic spectral analysis. These complex studies indicated the samples to be naturally mummified human brain tissue and that this process had occurred due to specific conditions within the cranial cavities after burial.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01625172
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  • 4
    Digitale Medien
    Digitale Medien
    Vascular and myofibrillar lesions in acute myoglobinuria associated with carnitine-palmityl-transferase deficiency (1992)
    Springer
    Virchows Archiv 421 (1992), S. 57-64 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Carnitine-palmityl-transferase deficiency ; Acute vascular lesions ; Acute myofibrillar lesions ; Ischaemia ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of severe exercise-induced myoglobinuria in a 14-year-old boy suffering from a carnitine-palmityl-transferase (CPT) defect is reported. Biopsies of the forearm muscle were examined using light and electron microscopy in the acute and recovery phases of the illness. The first biopsy showed the presence of scattered foci of necrosis where necrotic fibres with occasional disruptions of the basal lamina were seen around injured capillaries. Various degrees of damage and different stages of evolution were found in these foci, which also contained regenerating muscle fibres. In the second biopsy, performed 2 weeks later, most of the fibres displayed a normal structure. Necrosis was no longer present. However, in some areas perivascular fibrosis was prominent, the fibres were small and irregularly shaped, and their nuclei often centrally located. These data strongly suggest that circulatory disorders and ischaemia, brought about by premature acute metabolic imbalance, could be involved in the development of exerciseinduced myolysis observed in CPT deficiency. The risk of fibrous cardiomyopathy in these patients is pointed out.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01607140
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  • 5
    Digitale Medien
    Digitale Medien
    The pathobiology of salivary gland (1992)
    Springer
    Virchows Archiv 421 (1992), S. 105-113 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Parotid gland ; ras ; Transgenic mouse ; Electron microscopy ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In the transgenic TG.SH (mouse mammary tumour virus/v-Ha-ras) mouse, designed to develop mammary tumours, occasional spontaneous salivary gland tumours have been reported, predominantly in males. The incidence and histomorphology of salivary gland tumours in 73 TG.SH mice were surveyed and in total, 21.9% developed both overt and microscopic parotid tumours. The majority developed between 73 and 150 days of age. In 31.5% of the TG.SH mice, occasional unilateral, but more frequently bilateral exophthalmos due to hyperplasia of the intraorbital (Harderian) lacrimal gland was observed. In 70% of these animals, parotid tumours developed later. Since Harderian gland hyperplasia, occurring as early as 5 weeks of age, preceded the development of palpable salivary gland lesions, this stigma is useful for the early selection of animals likely to progress to tumour formation. Before tumour-bearing transgenic mice are considered to be suitable models of human neoplastic disease, morphological characterization is necessary to ensure that the tumours are histologically representative of the human lesions for which they are potential models. In this study, all parotid tumours consisted of acinar-like glandular structures with central lumina discernible by electron microscopy. Ultrastructurally, secretory granules evident in the apical cytoplasm of the tumour cells resembled the zymogen granules of the normal parotid acinar cell, and some cells had a prominent complement of rough endoplasmic reticulum. These features, along with focal amylase expression detected immunohistochemically in some parotid tumours, identified these neoplasms as acinic cell carcinomas that mimic the human salivary gland acinic cell carcinoma faithfully.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01607042
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  • 6
    Digitale Medien
    Digitale Medien
    Electron microscopic study of paired helical filaments and cerebral amyloid using a novel en bloc silver staining method (1992)
    Springer
    Virchows Archiv 420 (1992), S. 519-525 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Silver staining ; Paired helical filaments ; Cerebral amyloid ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A one step en bloc silver staining method which was originally established to study nucleolar organizer regions has been applied for the demonstration of both paired helical filaments (PHF) and extracellular cerebral amyloids in semi-thin sections and at the electron microscopic level. The three forms of PHF can be visualized: (1) neurofibrillary tangles are shown in all stages from first appearance in form of intracellular patches of PHF to severely degenerated shadow-like “ghost” tangles; (2) neuropil threads are distinctly stained in great numbers; and (3) PHF are easily detected as neuritic components in amyloid plaques. All forms of fibrillar extracellular amyloid structures, i.e. “diffuse”, “classical” and “burnt out” plaques, are well demonstrated; congophilic angiopathy reveals amyloid preferentially in arteries and arterioles of the leptomeninges and cortex ranging from small circumscribed patches to large circumferential amounts with occasional plaque-like condensations or broad loose accumulations of amyloid; perivascular cuffs and laminar subpial deposits of amyloid are stained as well. At the electron microscopic level all lesions are clearly visible in non uranyl/lead-stained specimens, characterized by varying numbers of silver grains on a pale background. The detailed demonstration of structures in archival material, which had been stored in paraffin and re-embedded for electron microscopy, is due to the demonstration of argyrophilic structures by the protective colloidal developer of gelatin and formic acid and to the proteolytic resistance of insoluble PHF and extracellular amyloids in plaques and congophilic angiopathy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600257
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  • 7
    Digitale Medien
    Digitale Medien
    Malignant paraganglioma of the uterus (1992)
    Springer
    Virchows Archiv 420 (1992), S. 453-457 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Uterus ; Paraganglioma ; Intracytoplasmic hyaline globules ; Immunohistochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We report a malignant uterine paraganglioma in a 40-year-old female, who died 7 months after the initial diagnosis. On light microscopy the tumour showed a typicalzellballen pattern as well as a pronounced cellular pleomorphism. In many tumour cells hyaline globules were demonstrated within the cytoplasm. Immunohistochemically the lesion was characterized by the presence of neuron-specific enolase, protein gene product 9.5 and synaptophysin, and electron microscopically by the occurrence of neurosecretory granules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01600518
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  • 8
    Digitale Medien
    Digitale Medien
    Occlusive microangiopathy by immunoglobulin (IgM-kappa) precipitation: pathogenetic relevance in paraneoplastic cryoglobulinemic neuropathy (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 423-426 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Peripheral neuropathy ; Cryoglobulinemia ; Immunohistochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Histological, immunohistochemical and ultrastructural sural nerve and skin biopsy findings in a case of cryoglobulinemia secondary to an IgM-kappa-producing non-Hodgkin lymphoma are described. The main finding was an occlusive microangiopathy present in both the sural nerve and the skin. Widespread cryoglobulin deposits of the proliferated vasa nervorum were associated with pronounced changes probably evoked by ischemia. Moderate perivascular inflammation, but no florid vasculitis was additionally present. Our observations indicate that occlusive microangiopathy by precipitated cryoglobulins may be a relevant pathogenetic factor in cryoglobulinemic peripheral neuropathy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00713536
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  • 9
    Digitale Medien
    Digitale Medien
    Presenile dementia with progressive supranuclear palsy tangles and Pick bodies: an unusual degenerative disorder involving the cerebral cortex, cerebral nuclei, and brain stem nuclei (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 128-134 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Progressive supranuclear palsy ; Neurofibrillary tangles ; Pick body ; Immunocytochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Degeneration of heterogeneous systems in the central nervous system, with widespread distribution of argyrophilic neuronal fibrillary inclusions, was found in a patient with presenile dementia. Atrophy was circumscribed in the frontal and temporal lobes. Neuronal loss was severe in the basal ganglia, subthalamic nucleus, and substantia nigra. Immunocytochemical study using anti-phosphorylated tau and anti-ubiquitin antibodies in conjunction with ultrastructural observations revealed two types of inclusions: neurofibrillary tangles (NFTs) of progressive supranuclear palsy (PSP) in the Edinger-Westphal nucleus, locus coeruleus, cerebellar dentate nucleus, inferior olivary nucleus, and posterior horn of the spinal cord; and Pick bodies (PBs) in the atrophied cerebral cortex and red nucleus. PSP-type NFTs and PBs have been demonstrated in a single case for the first time. Despite their pathognomonic significance in certain disorders, we suggest that these inclusions may reflect a form of cytoskeletal disorganization, which is not entirely restricted to a single disease entity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00311384
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  • 10
    Digitale Medien
    Digitale Medien
    Sural nerve immunoreactivity for nerve growth factor receptor in a case of localized hypertrophic neuropathy (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 547-553 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Localized hypertrophic neuropathy ; Electron microscopy ; Immunohistochemistry ; Nerve growth factor receptor ; Schwann cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Immunoreactivity for nerve growth factor receptor (NGFR) was examined using a monoclonal antibody against human NGFR in the sural nerve of a 24-year-old woman, affected by localized hypertrophic neuropathy (LHN). NGFR expression was correlated with electron microscopy and with immunoreactivity for S-100 protein, laminin, HLA-DR, HNK-1, P0 glycoprotein and neurofilament peptides. Our results indicate that in LHN most of whorl-forming cells are NGFR positive and S-100 protein or HLA-DR negative. These data along with the ultrastructural features suggest their origin from perineurium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00310035
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  • 11
    Digitale Medien
    Digitale Medien
    Immunohistochemistry of cholinergic receptors (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 407-429 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Acetylcholine receptors ; Immunocytochemistry ; Electron microscopy ; Human motor endplate ; Human cerebral cortex ; Neurodegenerative disorders
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Acetylcholine and its receptors are involved in a variety of important signal transduction processes. As shown here paradigmatically for the human neuromuscular junction and the cerebral cortex, acetylcholine receptors can be visualized immunohistochemically at the cellular and subcellular level under physiological and pathological conditions. At normal motor endplates nicotinic cholinoceptors are localized at the surface of the postsynaptic junctional folds. In myasthenic syndromes investigation of muscle biopsies enables the diagnosis of receptor deficiencies at the ultrastructural level. In normal cerebral cortex pyramidal neurons are equipped with both nicotinic and muscarinic acetylcholine receptors localized to postsynaptic densities. In neuropsychiatric diseases cholinoceptor expression can be monitored at the cellular level by quantititative assessment of immunolabeled cortical neurons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185457
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  • 12
    Digitale Medien
    Digitale Medien
    Ultrastructural study of ascending projections to the lateral mammillary nucleus of the rat (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 547-557 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Dorsal tegmental nucleus of Gudden ; Laterodorsal tegmental nucleus ; Synaptic organization ; Anterograde tracing study ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We examined the synaptic organization of ascending projections from the pars ventralis of the dorsal tegmental nucleus of Gudden (TDV) and the laterodorsal tegmental nucleus to the lateral mammillary nucleus (LM). The LM neuropil consists of terminals containing pleomorphic synaptic vesicles and forming symmetric synaptic contact, and terminals containing round synaptic vesicles and forming asymmetric synaptic contact. They make up 63% and 37%, respectively, of all axodendritic terminals. All axosomatic terminals contain pleomorphic vesicles and make symmetric contact. Following injection of WGA-HRP into the TDV, many anterogradely labeled terminals and retrogradely labeled cells are found in the LM. Labeled terminals contact mainly proximal (more than 2 μm diameter) and intermediate (1–2 μm diameter) dendrites. Serial ultrathin sections of the LM show that 55% of axosomatic terminals are labeled anterogradely. Following injection of WGA-HRP into the laterodorsal tegmental nucleus, many anterogradely labeled terminals are found in the LM, but no retrogradely labeled cells are present. Labeled terminals contact mainly distal (less than 1 μm diameter) and intermediate dendrites as well as somata. In the LM neurons, 46% of axosomatic terminals are labeled anterogradely. All labeled terminals from these nuclei contain pleomorphic vesicles and make symmetric synaptic contact. These results indicate that almost all axosomatic terminals come from the TDV and the laterodorsal tegmental nucleus, which send inhibitory inputs to the lateral mammillary nucleus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185614
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  • 13
    Digitale Medien
    Digitale Medien
    Neuronal autophagic vacuoles in experimental scrapie and Creutzfeldt-Jakob disease (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 134-139 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Scrapie ; Creutzfeldt-Jakob disease ; Neuronal autophagy ; Neuropathology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We report the presence of autophagic vacuoles (AV) in neuronal perikarya and neuronal processes of rodents with experimental scrapie and Creutzfeldt-Jakob disease. AV were composed of sequestrated cytoplasmic areas containing ribosomes and occasionally mitochondria and small secondary vacuoles. The formation of AV may contribute to neuronal degeneration and ultimately to neuronal loss.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00308472
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  • 14
    Digitale Medien
    Digitale Medien
    Paired helical filaments in astrocytes: electron microscopy and immunohistochemistry in a case of atypical Alzheimer's disease (1992)
    Springer
    Acta neuropathologica 83 (1992), S. 228-232 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Alzheimer's disease ; Astrocytes ; Electron microscopy ; Immunohistochemistry ; Paired helical filaments
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A 54-year-old man who had cerebellar ataxia and pseudobulbar palsy at the age of 29 years, and soon developed dementia, myoclonus and convulsions, died after about 20 years in a vegetative state. Histological examination of the extensively atrophic and devastated brain (680 g) revealed the almost total loss of cerebral cortical neurons associated with numerous β-protein amyloid plaques, many extracellular tangles and a large number of hypertrophic astrocytes, and prominent amyloid angiopathy. The astrocytes were frequently immunopositive for anti-human tau antibody (anti-htau) and anti-ubiquitin antibody (anti-ubi). Double immunostaining with anti-htau and anti-glial fibrillary acidic protein (GFAP) antibody clearly demonstrated htau-positive domains within the GFAP-positive perikarya/and processes of several astrocytes. Electron microscopy of the hippocampal CA1, which was completely devoid of pyramidal neurons, revealed, in astrocytes, abnormal filaments indistinguishable from the paired helical filaments (PHFs) seen in neurons. On immunoelectron microscopy, the filaments were observed to be labeled with anti-htau and anti-ubi, exhibiting the same immunohistochemical features as neuronal PHFs. This is the first demonstration of clearly constricted and both tau- and ubiquitin-positive PHFs in astrocytes, indicating that, in some special conditions like in our case, processes similar to those that attack neurons also affect astrocytes and ultimately make the latter form PHFs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296783
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  • 15
    Digitale Medien
    Digitale Medien
    Retinal photoreceptor fine structure in the velvet cichlid (Astronotus ocellatus) (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 363-370 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Retinal photoreceptors ; Electron microscopy ; Teleost ; Astronatus ocellatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The structure and arrangement of the retinal photoreceptors of the velvet cichlid fish (Astronotus ocellatus) have been studied by light and electron microscopy. Rods, single cones and double (twin) cones are present. In the light-adapted state, rods are very tall cells that reach deep into the retinal epithelial (RPE) layer. The long outer segment is composed of discs of uniform diameter displaying one or two incisures. The rod inner segment shows a distal ellipsoid of mitochondria, and then narrows dramatically in the myoid region. Rod nuclei are electron dense and located deep in the outer nuclear layer. Rod synaptic spherules are small and show two to three invaginated synaptic sites as well as superficial synapses. Single cones are similar to the individual members of a double cone and all display a short tapering outer segment, a large ellipsoid of mitochondria and a myoid rich in rough endoplasmic reticulum, polysomes, Golgi zones and autophagic vacuoles. Double cones have extensive subsurface cisternae along their entire contiguous surfaces. Cone nuclei are large and vesicular and located close to or through the external limiting membrane. The synaptic pedicles of cones are larger, more electron lucent, and display more invaginated (ribbon) synapses as well as conventional (superficial) synaptic sites than do the rod spherules. Rod photoreceptors certainly undergo retinomotor movements and it is probable that cones do as well. In the light-adapted state the cone photoreceptors are arranged in a repeating square mosaic pattern with one single cone surrounded by four double (twin) cones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185986
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  • 16
    Digitale Medien
    Digitale Medien
    Intraventricular infusion of N-methyl-D-aspartate (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 630-637 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Dentrites ; Excitotoxicity ; Glutamate ; N-Methyl-d-aspartate ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This study documents the ultrastructural features of acute neuronal injury following N-methyl-d-aspartate (NMDA) receptor activation. NMDA (100 nmol/μl) or vehicle was infused over a 15-min period into the lateral ventricle of adult rats. After perfusion fixation, specimens demonstrating normal and abnormal patterns of vascular permeability to horserdish peroxidase were sampled for ultrastructural analysis. In NMDA-infused rats, brain regions exhibiting protein extravasation contained swollen dendritic profiles and abnormal neuronal perikarya. Although periventricular regions were most severely affected, parenchymal abnormalities were also detected in the cerebral cortex, septum, striatum, thalamus, hypothalamus and cerebellum. Mildly affected dendrites contained dark compact mitochondria, while in severely swollen dendrites mitochrondia were enlarged with ruptured cristae. Focal sites of plasma membrane disruption were also detected within swollen dendrites. Swollen neurons commonly displayed peripheral pallor and increased numbers of cytoplasmic vacuoles. Other neurons appeared dark and shrunken, some containing disrupted mitochrondria and pyknotic nuclei. Pretreatment with the NMDA antagonist MK-801 (2 mg/kg) attenuated the neuronal and dendritic alterations. In conditions where cerebrospinal fluid levels of glutamate are abnormally elevated, excessive NMDA receptor activation may lead to early vascular and neuronal complications which could work in concert to promote brain injury.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227740
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  • 17
    Digitale Medien
    Digitale Medien
    Intraventricular infusion of N-methyl-d-aspartate (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 621-629 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Blood-brain barrier ; Endothelium ; Excitotoxicity ; N-Methyl-d-aspartate ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The purpose of this study was to document the early cerebrovascular consequences of excessive N-methyl-d-aspartate (NMDA) receptor activation. Five microliters of NMDA (100 nmol/μl) or vehicle was infused over a 15-min period into the lateral ventricle of adult rats. The protein tracer horseradisch peroxidase (HRP) was injected intravenously for blood-brain bartier (BBB) studies. The intraventricular infusion of vehicle (n=5) caused no alterations in arterial blood pressure or microvascular damage away from the intraventicular probe tract. In contrast, NMDA infusion (n=8) led to a gradual increase in arterial blood pressure (mean 36 mm Hg). Multifocal regions of HRP extravasation were observed bilaterally throughout the neuraxis following NMDA infusion. Sites of BBB disruption and hemorrhage included brain regions bordering ventricular spaces. In addition, isolated foci of protein extravasation were commonly detected in the cerebral cortex, thalamus, basal forebrain, septum and cerebellum. Pretreatment with the noncompetitive NMDA antagonist MK-801 (2 mg/kg) substantially reduced the BBB responses to NMDA. However, microvascular abnormalities were seen in NMDA-infused rats where blood pressure elevations were inhibited by blood removal. In addition to neurons, cerebral blood vessels are also acutely affected by NMDA receptor activation. Blockage of NMDA receptor channels following brain injury may potentially provide protection by attenuating BBB breakdown and subsequent brain edema.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227739
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  • 18
    Digitale Medien
    Digitale Medien
    Increased iron content in the putamen of patients with striatonigral degeneration (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 328-330 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Striatonigral degeneration ; Putaminal pigment ; Iron ; Atomic absorption spectroscopy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We measured the total content of iron, cooper, zinc and manganese in the putamen of four patients with striatonigral degeneration (SND) and age-and gender-matched normal controls. The iron content in the SND patients was five times greater than in the controls. Electron microscopic histochemistry revealed the iron reaction products in the pigments showing a triphasic pattern of coarse, electron-dense globules, fine granular and fibrillary materials, and lamellated structures. These findings suggest that increased iron deposition may be related to pigment formation in the putament of SND.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227827
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  • 19
    Digitale Medien
    Digitale Medien
    Cerebral granular cell tumors: report of a case and a note on their nature and expected behavior (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 680-685 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Histiocytic markers ; Astrocytoma ; Electron microscopy ; Glial fibrillary acidic protein ; Granular cell tumor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of cerebral granular cell tumor (GCT) is reported. Histologically, the growth was composed of benign astrocytes, granular cells and transitional forms between both elements. Glial fibrillary acidic protein was detected in the glial component and, to a lesser extent, in the granular cells. Alpha-1-antichymotrypsin was demonstrated in the latter component only. Ultrastructural study also supported the evidence that neoplastic astrocytes became granular cells. The survey of the literature and our own results suggest that GCTs in this particular location, even when histologically benign, seem to have a worse prognosis than the low-grade supratentorial astrocytomas.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227746
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  • 20
    Digitale Medien
    Digitale Medien
    Retinal pigment epithelial fine structure in the velvet cichlid (Astronotus ocellatus) (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 371-377 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Retinal pigment epithelium (RPE) ; Electron microscopy ; Teleost ; Astronatus ocellatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The morphology of the retinal pigment epithelium (RPE), choriocapillaris and Bruch's membrane (complexus basalis) have been studied by light and electron microscopy in the velvet cichlid (Astronotus ocellatus). The RPE is composed of a single layer of large columnar cells. The basal (scleral) border of these cells is minimally infolded, whereas the apical (vitreal) surface displays numerous pigment-laden processes which in light-adaptation surround both rod and cone outer segments. Laterally the RPE cells are joined by a series of basally located tight junctions. Wandering phagocytes are a constant feature within this epithelial membrane. The RPE cells display a large, vesicular nucleus, numerous mitochondria, much smooth endoplasmic reticulum, polysomes, myeloid bodies, phagosomes and melanosomes. Rough endoplasmic reticulum is relatively scarce within these cells. Although only light-adapted specimens were examined, it is thought that the melanosomes are capable of extensive retinomotor movement. The endothelium of the choriocapillaris facing Bruch's membrane is typically very thin but shows few fenestrations. Bruch's membrane is typical of other teleost species in that it is composed of only three layers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00185987
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  • 21
    Digitale Medien
    Digitale Medien
    The cellular network of interstitial cells associated with the deep muscular plexus of the guinea pig small intestine (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 519-527 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Intestine ; Interstitial cells ; Innervation ; Electron microscopy ; Guinea pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Systematic examination using electron microscopic montages and serial sections has demonstrated that three types of interstitial cell, namely gap junction-rich cells, glycogen-rich cells and fibroblast-like cells, are densely located along the whole extent of the deep muscular plexus of the guinea pig small intestine. They tend to be distributed in an alternating fashion in the cellular network, connected with muscle cells of the outer, circular layer by means of gap junctions. These three types of interstitial cell show close relations to two types of nerve varicosity: one type is characterized by clear round vesicles with diameters of about 50 nm, and the other by flattened vesicles measuring about 35 nm by 70 nm. Electron-dense patches have been observed at the cytoplasmic side of the axonal membranes. Muscle cells of both inner and outer circular layers also show close relations to these two types of nerve varicosity. These morphological features are discussed with the implication that they may have some regulatory role in intestinal movement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00186974
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  • 22
    Digitale Medien
    Digitale Medien
    Effects of cepharanthine and minoxidil on proliferation, differentiation and keratinization of cultured cells from the murine hair apparatus (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 290-296 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Cepharanthine ; Minoxidil ; Culture ; Hair cells ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of cepharanthine and minoxidil on proliferation, differentiation and keratinization of cultured cells from the murine hair apparatus were examined electron microscopically. Both cepharanthine and minoxidil stimulated cell proliferation and delayed initiation of differentiation and keratinization of the cultured cells. On day 6, most control cells (87%) cultured in a 0.03 mM calcium medium without cepharanthine and minoxidil were differentiated into several subpopulations corresponding to those of in vivo cell layers of the hair apparatus, while most of the cells cultured with cepharanthine (71%) or minoxidil (70%) were still immature. On day 13, the number of degenerated cells increased (63%) in the control culture, whereas in the culture treated with cepharanthine or minoxidil, cell degeneration scarcely occurred (5% and 8%, respectively). Differentiated cells having tonofilaments were often observed in the cepharanthine- and minoxidil-treated cultures (76% and 72%, respectively). Elevation of extracellular calcium up to 1.0 mM induced keratinization (34%) in the control culture on day 6, while no keratinized cells were observed in the cepharanthine- or minoxidil-treated culture. On day 13 keratinization similarly occurred in the cultures with cepharanthine (30%) or minoxidil (48%). These results show that both cepharanthine and minoxidil may directly influence proliferation, differentiation and keratinization of cultured cells from the hair apparatus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00372583
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  • 23
    Digitale Medien
    Digitale Medien
    Ultrastructural localization of actin in normal human skin (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 242-245 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Immunogold ; Electron microscopy ; Human skin ; Actin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Normal human skin was embedded in Lowicryl K4M. Actin microfilaments were localized by applyinga postembedding immunogold technique using the monoclonal anti-actin antibody HHF35. Actin microfilaments are part of the cytoskeleton in muscle and nonmuscle cells. Together with myosin they produce contraction. The antibody labelled myofilaments in smooth muscle arrector pili cells, myoepithelial cells and pericytes. In sweat gland cells the microvilli system, a zone beneath the cytoplasma membrane correponding to the adhesion belt region, and apocrine decapitation formations showed labelling.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00375802
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  • 24
    Digitale Medien
    Digitale Medien
    Basal lamina-like material and hemidesmosome-like structures associated with dermal papilla cells in the normal human anagen hair follicle (1992)
    Springer
    Archives of dermatological research 284 (1992), S. 303-306 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Hair follicle ; Basal lamina ; Dermal papilla cells ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00372585
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  • 25
    Digitale Medien
    Digitale Medien
    Electron-microscopic description of accretions occurring on tips of infected and non-infected central venous catheters (1992)
    Springer
    Intensive care medicine 18 (1992), S. 464-468 
    Details
    ISSN: 1432-1238
    Schlagwort(e): Catheter ; Electron microscopy ; Infection ; Adherence ; Candida albicans
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Objective The purpose of the study was do describe the architecture of accretions occurring on the tips of central venous catheters (CVC). Design A conservative procedure was used followed by two different techniques of electron microscopy Setting and patients the study included 19 catheters which have been used on intensive cared adults, and which were chosen among those of parallel 300 CVC study. Measurements and results CVC were considered sterile, contaminated, colonized or infected according to microbiological and clinical criteria. CVC were found to remain much cleaner than in past clescriptions. When present, accretions were located on the olive-shaped end, and displayed stratified structures with three types of material: amorphous material, thrombus components and inflammatory cells. Bacteria were not seen, even on culture positive CVC. Candida albicans was found on one CVC in the cytoplasm of ganulocytes, and made xio direct contact with the plastic surface. Conclusion This technique should contribute to the understanding of the pathobiology of CVC infection and provide information proving or precluding the involvement of microbial adherence to polymers in vivo.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01708582
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  • 26
    Digitale Medien
    Digitale Medien
    Calcium binding protein (calbindin D28k) immunoreactivity in the hamster superior colliculus: ultrastructure and lack of co-localization with GABA (1992)
    Springer
    Experimental brain research 89 (1992), S. 115-124 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Immunocytochemistry ; Visual pathways ; Electron microscopy ; Hamster
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The expression of specific calcium binding proteins is being used increasingly as a potential neuroanatomical marker for neurons with similar functions. In this study, the distribution of calbindin D28k in the superior colliculus (SC) of adult hamsters was examined by light and electron microscopy. Calbindin immunoreactivity was prominent in specific regions and laminae of the SC throughout its rostrocaudal extent, and was found to label horizontal, vertical and stellate cell types. In addition, calbindin label highlighted “bridges” of neuronal processes in the intermediate layers. The most frequent calbindin-immunoreactive profiles seen in the electron microscope were dendrites, some of which were post-synaptic to apparent retinal ganglion cell axon terminals. Labelled axons and axon terminals were less frequently encountered. There was considerable overlap between the size distribution of calbindin D28k-immunoreactive neurons and that of GABA-immunoreactive or Nissl stained neurons in the SC. However, using a double fluorescent labelling technique, and examination of the tissue with confocal laser microscopy, no neurons were observed in the hamster SC that showed immunoreactivity for both calbindin and GABA. In this regard, the SC is similar to the mammalian lateral geniculate nucleus and the pretectum, but differs from the neocortex, where calbindin and GABA are colocalized. The demonstration in the SC, as well as other parts of the nervous system, of sub-populations of neurons that contain distinct calcium-binding proteins suggests that these neurons have different functional properties. Correlative studies may clarify the relevance of these cytoplasmic components as cell markers, as well as their different patterns of association with neurotransmitters and peptides.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00229008
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  • 27
    Digitale Medien
    Digitale Medien
    High-pressure freezing of soybean nodules leads to an improved preservation of ultrastructure (1992)
    Springer
    Planta 188 (1992), S. 155-163 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Bradyrhizobium ; Electron microscopy ; Glycine (root nodules) ; High-pressure freezing ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract High-pressure freezing of chemically untreated nodules of soybean (Glycine max (L.) Merr.), in sharp contrast to chemical fixation and prefixation, appears to preserve the ultrastructure close to the native state. This is supported by the observation that the peribacteroid membrane of high-pressure-frozen samples is tightly wrapped around the bacteroids, a finding that is fully consistent with the current views on the physiology of oxygen and metabolite transport between plant cytosol and bacteroids. In soybean root nodules, the plant tissue and the enclosed bacteria are so dissimilar that conventional aldehyde-fixation procedures are unable to preserve the overall native ultrastructure. This was demonstrated by high-pressure freezing of nodules that had been pre-fixed in glutaraldehyde at various buffer molalities: no buffer strength tested preserved all ultrastructural aspects that could be seen after high-pressure freezing of chemically untreated nodules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00216809
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  • 28
    Digitale Medien
    Digitale Medien
    Studies on the hepatotoxicity induced by bis (tributyltin) oxide (1992)
    Springer
    Archives of toxicology 66 (1992), S. 182-187 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Bis(tributyltin) oxide ; Liver ; Electron microscopy ; X-ray microanalysis ; Biochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The toxic effects of bis (tributyltin) oxide (TBTO) on the rat liver were studied with an electron microscope and the accumulation sites of tin were determined with an X-ray microanalyzer. The activities of serum enzymes and the concentration of serum bilirubin were also analyzed. Male Wistar rats received an intramuscular injection of 0.5 ml/kg of TBTO. Marked swelling of the mitochondria appeared in the hepatocytes 4 h after injection of TBTO. Cytoplasmic vacuoles, which contained degenerated mitochondria, gradually increased in number in these hepatocytes. This in turn may have caused a decrease in the volume of hepatic cell cords and an enlargement of sinusoids in the entire hepatic lobule. However, fine structures of intrahepatic bile ducts were not altered. By X-ray microanalysis, tin peaks were preferentially obtained from swollen mitochondria of the hepatocytes. By polarographic analysis of the respiratory responses of mitochondria, it was demonstrated that rates of state 4 respiration and respiratory control ratio were significantly disturbed in TBTO-treated rats in comparison with those of controls. The activities of AST (aspartate aminotransferase) and ALT (alanine aminotransferase) were significantly increased after TBTO treatment, but those of ALP (alkaline phosphatase), LAP (leucine aminopeptidase) and total bilirubin were not changed. These results indicated that parenterally administered TBTO accumulated in the liver cell mitochondria and disturbed oxidative phosphorylation. Mitochondrial dysfunction might induce severe damage of the hepatocytes. Four days after injection of TBTO, hepatic structures and chemical indices were almost restored by the regeneration of hepatocytes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01974012
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  • 29
    Digitale Medien
    Digitale Medien
    Dynamics of PhiX174 protein E-mediated lysis of Escherichia coli (1992)
    Springer
    Archives of microbiology 157 (1992), S. 381-388 
    Details
    ISSN: 1432-072X
    Schlagwort(e): PhiX174 ; Bacterial lysis ; Escherichia coli ; Electron microscopy ; Membranes ; Cell envelope
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Expression of cloned gene E of bacteriophage PhiX174 induces lysis by formation of a transmembrane tunnel structure in the cell envelope of Escherichia coli. Ultrastructural studies of the location of the lysis tunnel indicate that it is preferentially located at the septum or at polar regions of the cell. Furthermore, the diameter and shape of individual tunnel structures vary greatly indicating that its structure is not rigid. Apparently, the contours of individual lysis tunnels are determined by enlarged meshes in the peptidoglycan net and the force produced at its orifice, by the outflow of cytoplasmic content. Once the tunnel is formed the driving force for the lysis process is the osmotic pressure difference between cytoplasm and medium. During the lysis process areas of the cytoplasmic membrane which are not tightly attached to the envelope are extended inward by the negative pressure produced during lysis. After cell lysis external medium can diffuse through the lysis tunnel filling the inner cell space of the still rigid bacterial ghosts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00248685
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  • 30
    Digitale Medien
    Digitale Medien
    Age-related immunoreactivity pattern in medulloblastoma (1992)
    Springer
    Child's nervous system 8 (1992), S. 326-331 
    Details
    ISSN: 1433-0350
    Schlagwort(e): Medulloblastomas ; Immunohistochemistry ; Cytokeratins ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Thirty-five paraffin-embedded medulloblastomas (19 from children and 16 from adults; 24 classic medulloblastomas, 10 desmoplastic medulloblastomas, 1 tumor with neuronal differentiation) were examined for reactions with antibodies against glial fibrillary acidic protein (GFAP), cytokeratins KL1 and MNF116, desmin, and vimentin. Only the tumor from the youngest patient, a 152-day-old boy, showed a positive immunoreaction for cytokeratins. Because of this age-related expression of cytokeratins in medulloblastomas primarily in very young children, cytokeratin positivity was interpreted as a sign of tumor immaturity. Five medulloblastomas showed scattered GFAP-positive reactive astrocytes and/or other positive, probably neoplastic, cells. Only two tumors showed GFAP immunoreactivity in unequivocally neoplastic cells. Of six tumors that reacted with vimentin, three showed strong reactivity throughout, one being the tumor from the 152-day-old boy. The remaining three demonstrated nests of vimentin-positive cells with weak or intense somatic immunoreactivity for vimentin. None of the 35 cases showed positivity for desmin, indicating that mesenchymal differentiation is restricted to the rare so-called medullomyoblastomas.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00296563
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  • 31
    Digitale Medien
    Digitale Medien
    The human placental transferrin receptor: Reconstitution into liposomes and electron microscopy (1992)
    Springer
    Bioscience reports 12 (1992), S. 471-482 
    Details
    ISSN: 1573-4935
    Schlagwort(e): Transferrin ; Receptor ; Isolation ; Reconstitution ; Liposomes ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Human transferrin receptor was isolated from Triton X-100 solubilized placental plasma membranes by a rapid one-step chromatographic procedure based on immunoadsorption of the receptortransferrin complex on anti-transferrin Sepharose and lectin-affinity on wheat germ agglutinin. Following exchange of Triton X-100 with CHAPS or n-octylglucoside, the purified receptor was incorporated into egg phosphatidylcholine liposomes upon, detergent removal by dialysis (lipid/protein ratio 15:1 to 45:1 (w/w) Reconstitution of the receptor was confirmed by trypsin cleavage to dissociate the large extracellular receptor domain from the liposomal membranes. Electron micrographs of the receptor-lipid recombinants negatively stained with sodium sillicotungstate, showed ographs of the receptor-lipid recombinants negatively stained with sodium sillicotungstate, showed that the receptor molecules distributed very inhomogeneously on the liposomes, most receptors being clustered. Single copies of the receptor were seen as elongate structures (5×10 nm) oriented with their long axis parallel to the liposome surface and separated from this by a 2–3 nm gap. This result provides evidence for a narrow connecting link between the globular extracellular receptor domain and the membrane spanning segment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01122035
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  • 32
    Digitale Medien
    Digitale Medien
    Exo-endocytosis in isolated peptidergic nerve terminals occurs in the sub-second range (1992)
    Springer
    Bioscience reports 12 (1992), S. 495-501 
    Details
    ISSN: 1573-4935
    Schlagwort(e): Electron microscopy ; secretion ; neuropeptides ; exocytosis ; endocytosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Exo- and endocytotic processes induced by depolarization of isolated neurosecretory nerve terminals show a close temporal correlation, which suggests a short time of integration of the neurosecretory granule membrane with the plasma membrane. In order to determine minimal time requirements for exocytosis-coupled endocytosis to occur, we have analyzed by electron microscopy uptake of horserdish peroxidase (HRP) as a fluid phase marker at the onset of depolarization. We have applied rapid mixing and sampling (quenched flow) to assess events in subsecond time peroids after stimulation. A significant number of labelled endocytotic vacuoles was observed during the first second of depolarization. This number then further increased by a factor of about 2 (within 5 s) and 4 (within 50s). Thus, as for exocytosis, the rate of endocytosis decreased considerably during prolonged stimulation. These data indicate i) that a substantial proportion of secretory granules undergoes exocytosis very shortly after stimulation, and ii) that, following exocytosis, the minimal time required for consecutive membrane retrieval is in the sub-second range.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01122037
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  • 33
    Digitale Medien
    Digitale Medien
    Effect of haloperidol and clozapine on the density of “perforated” synapses in caudate, nucleus accumbens, and medial prefrontal cortex (1992)
    Springer
    Psychopharmacology 106 (1992), S. 45-52 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Haloperidol ; Clozapine ; Perforated synapses ; Electron microscopy ; Tardive dyskinesia ; Extrapyramidal syndrome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Perforated synapses, which contain a discontinuous density along the postsynaptic membrane, can increase or decrease in numbers following various behavioral and biochemical manipulations. We have previously established that 14-day treatment with haloperidol causes an increase in the number of perforated synapses within the caudate nucleus (dorsolateral region) but not the nucleus accumbens (Meshul and Casey 1989). This effect was reversed if the animals were withdrawn from the drug for an equivalent period of time. We have now further examined the effects of haloperidol administration, which is associated with a high incidence of extrapyramidal side effects (EPS) and tardive dyskinesia (TD), and assessed the effects of clozapine, which appears to have a lower potential for inducing EPS and TD. Administration of haloperidol for 2 weeks significantly increased the percentage of perforated synapses in the caudate, but not in the nucleus accumbens or layer VI of medial prefrontal cortex (MPCx). There was an increase in specific [125I]epidepride binding to D-2 receptors in the caudate nucleus and MPCx following haloperidol. Administration of clozapine for 2 weeks did not affect the percentage of perforated synapses in any of the three dopamine (DA)-rich regions that were examined. There was an increase in specific [3H]SCH 23390 binding to D-1 receptors and in specific [125I]epidepride binding to D-2 receptors only within MPCx following clozapine. The absence of any change in the density of perforated synapses within the dorsolateral caudate nucleus following clozapine correlates with: 1) the lack of effect on specific DA receptor binding or down regulation of serotonin (5-HT2) receptors (as reported by others), or 2) the inability in clozapine-treated animals to depolarize block substantia nigra (A9) DA neurons. These results may be related to the low incidence of EPS and TD observed with clozapine.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02253587
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  • 34
    Digitale Medien
    Digitale Medien
    The metathoracic wing-hinge chordotonal organ of an atympanate moth, Actias luna (Lepidoptera, Saturniidae): a light- and electron-microscopic study (1992)
    Springer
    Cell & tissue research 267 (1992), S. 455-471 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Chordotonal organ ; Scolopidium ; Homology ; Electron microscopy ; Sensilla ; Evolution ; Actias luna (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The structure of a simple chordotonal organ, the presumed homologue of the noctuoid moth tympanal organ, is described in the atympanate moth, Actias luna. The organ consists of a proximal scolopidial region and a distal strand, which attaches peripherally to the membranous cuticle ventral to the hindwing alula. The strand is composed of elongate, microtubule-rich cells encased in an extracellular connective tissue sheath. The scolopidial region houses three mononematic, monodynal scolopidia, each comprised of a sensory cell, scolopale cell, and attachment cell. The dendritic apex is octagonally shaped in transverse section, its inner membrane lined by a laminated structure reminiscent of the noctuoid tympanal organ ‘collar’. A 9+0-type cilium emerges from the dendritic apex, passes through both the scolopale lumen and cap, and terminates in an extracellular space distal to the latter. Proximal extensions of the attachment cell and distal prolongations of the scolopale cell surrounding the cap are joined by an elaborate desmosome, with which is associated an extensive electron-dense fibrillar plaque. Within the scolopale cell, this plaque constitutes the scolopale ‘rod’ material. The data are discussed in terms of both the organ's potential function, and its significance as the evolutionary proto-type of the noctuoid moth ear.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319368
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  • 35
    Digitale Medien
    Digitale Medien
    Synaptic contacts of tyrosine hydroxylase-immunoreactive elements in the inner plexiform layer of the retina of Bufo marinus (1992)
    Springer
    Cell & tissue research 267 (1992), S. 525-534 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Retina ; Dopaminergic neurons ; Synapses ; Inner plexiform layer ; Immunocytochemistry ; Electron microscopy ; Bufo marinus (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Tyrosine hydroxylase (TH) immunocytochemistry was utilized to quantify dopaminergic synapses in the inner plexiform layer of the retina of Bufo marinus. Since dopaminergic cells have bistratified dendritic arborisation in the inner plexiform layer, attention was given to the segregation of synapses between the scleral and the vitreal sublaminae. Light-microscopically, a more elaborate dendritic branching was observed in the scleral than in the vitreal sublamina. In contrast, about 55% of synapses occurred in the vitreal one fifth of the inner plexiform layer, 30% in the scleral fifth, and 15% in the intermediate laminae. Input sources and output targets showed only minor quantitative differences between sublaminae 1 and 5. TH-immunoreactive processes were found in presynaptic (62.8%) and postsynaptic (37.2%) positions. Synapses to the stained dendrites derived from bipolar (40.4%) and amacrine (59.6%) cells, whereas outputs from the TH-positive processes were directed to amacrine cells (56.8%) and to small and medium-sized dendrites (35.4%); at least some of these can be considered as ganglion cell dendrites. TH-positive profiles neither formed synapses with each other nor were presynaptic to bipolar cell terminals. Junctional appositions of the immunoreactive profiles were occasionally seen on non-stained amacrine and ganglion cell dendrites in the scleral sublamina of the inner plexiform layer and on optic axons in the optic fibre layer. Although dopaminergic cells are mainly involved in amacrine-amacrine interactions, inputs from bipolar terminals and outputs to ganglion cell dendrites were also substantial, suggestive of a role also in vertical information processing.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319375
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  • 36
    Digitale Medien
    Digitale Medien
    Cellular differences in the regeneration of murine skeletal muscle: a quantitative histological study in SJL/J and BALB/c mice (1992)
    Springer
    Cell & tissue research 269 (1992), S. 159-166 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Regeneration ; Skeletal muscle ; Injury ; Autoradiography ; Morphometry ; Electron microscopy ; Mouse (SJL/J BALB/c)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Skeletal muscle regeneration in SJL/J and BALB/c mice subjected to identical crush injuries is markedly different: in SJL/J mice myotubes almost completely replace damaged myofibres, whereas BALB/c mice develop fibrotic scar tissue and few myotubes. To determine the cellular changes which contribute to these differential responses to injury, samples of crushed tibialis anterior muscles taken from SJL/J and BALB/c mice between 1 and 10 days after injury were analysed by light and electron microscopy, and by autoradiography. Longitudinal muscle sections revealed about a 2-fold greater total mononuclear cell density in SJL/J than BALB/c mice at 2 to 3 days after injury. Electron micrographs identified a similar proportion of cell types at 3 days after injury. Autoradiographic studies showed that the proportions of replicating mononuclear cells in both strains were similar: therefore greater absolute numbers of cells (including muscle precursors and macrophages) were proliferating in SJL/J muscle. Removal of necrotic muscle debris in SJL/J mice was rapid and extensive, and by 6 to 8 days multinucleated myotubes occupied a large part of the lesion. By contrast, phagocytosis was less effective in BALB/c mice, myotube formation was minimal, and fibrotic tissue conspicuous. These data indicate that the increased mononuclear cell density, more efficient removal of necrotic muscle, together with a greater capacity for myotube formation in SJL/J mice, contribute to the more successful muscle regeneration seen after injury.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384736
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  • 37
    Digitale Medien
    Digitale Medien
    Differential localization of leu-enkephalin and hyperglycemic hormone in axon terminals of the sinus gland of the crabsCarcinus maenas, eriocheir sinensis, andUca pugilator (1992)
    Springer
    Cell & tissue research 270 (1992), S. 521-526 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Enkephalins ; Neuropeptides ; Neurohemal organ ; Immunogold ; Electron microscopy ; Carcinus maenas, Uca pugilator, Eriocheir sinensis (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Leu-enkephalin containing secretory granules were demonstrated in axon terminals of immunogoldlabeled electron-microscopic sections of the sinus gland of three brachyuran crustaceans. These granules have a diameter of 120+-15 nm and differ in electron density from those located in adjacent terminals containing hyperglycemic or molt-inhibiting hormone. These neurohormones do not show co-localization with leu-enkephalin. The cross-reactivity of leu-enkephalin antiserum with met-enkephalin is less than 1%. The sinus glands of the three species examined show no immunoreactivity for FMRF-amide. A modulatory activity of endogenous enkephalin by paracrine mechanisms is suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00645054
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  • 38
    Digitale Medien
    Digitale Medien
    Immuno-electron-microscopic localization of basic fibroblast growth factor in the dystrophic mdx mouse masseter muscle (1992)
    Springer
    Cell & tissue research 270 (1992), S. 569-576 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Basic fibroblast growth factor ; Regeneration ; Degeneration ; Immunohistochemistry ; Electron microscopy ; Masseter muscle ; Myoneural junction ; Mouse (dystrophic mdx)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The localization of basic fibroblast growth factor (bFGF)-like immunoreactivity in the masseter muscle of dystrophic mdx mice on postnatal day 28 was investigated by immunoblot analysis and electron microscopy. Crude homogenate of the masseter muscle, when subjected to immunoblotting with a bFGF antiserum, exhibited a main band with the same molecular weight (18 kDa) as bovine bFGF. By electron microscopy, bFGF immunoreactivity was detected in small regenerating myocytes; the smaller cells were the premature myocytes, the most intense staining was the immunoreactivity within the cytoplasm. Putative precursors of the muscle cells with a few myofilaments, which were most intensely labeled with anti-bFGF, contacted each other and possibly developed into multinucleated myocytes through cell fusion. Mature myocytes with densely packed myofilaments and peripherally located nuclei did not exhibit bFGF immunoreactivity; they formed myoneural junctions with motor nerve endings immunoreactive for bFGF. Early differentiating myocytes with intense bFGF-like immunoreactivity did not make contact with immunoreactive nerve terminals. Degenerating large myocytes with a limited number of distorted and/or disrupted myofilaments exhibited electron-dense deposits in the cristae of mitochondria; these deposits were not abolished by immunoadsorption control experiments. Thus, the cell-size-dependent decrease in bFGF immunoreactivity in regenerating but not in degenerating myocytes provides a morphological basis for an autoregulatory role of bFGF in muscle regeneration. This study suggests that neuronal bFGF is not involved in initial muscle regeneration in the dystrophic mdx mouse.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00645060
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  • 39
    Digitale Medien
    Digitale Medien
    Ovarian innervation develops before initiation of folliculogenesis in the rat (1992)
    Springer
    Cell & tissue research 270 (1992), S. 87-93 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Ovarian nerves ; Development ; Folliculogenesis ; Tyrosine hydroxylase ; Immunohistochemistry ; Electron microscopy ; Rat (Sprague Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Sympathetic neurotransmitters have been shown to be present in the ovary of the rat during early postnatal development and to affect steroidogenesis before the ovary becomes responsive to gonadotropins, and before the first primordial follicles are formed. This study was undertaken to determine if development of the ovarian innervation is an event that antedates the initiation of folliculogenesis in the rat, Rattus norvegicus. Serial sections of postnatal ovaries revealed a negligible frequency of follicles 24 h after birth (about 1 primordial follicle per ovary). Twelve hours later there were about 500 follicles per ovary, a number that more than doubled to about 1300 during the subsequent 12 h, indicating that an explosive period of follicular differentiation occurs between the end of postnatal days 1 and 2. Electron microscopy demonstrated that before birth the ovaries are already innervated by fibers containing clear and dense-core vesicles. Immunohistochemistry performed on either fetal (day 19) or newborn (less than 15h after birth) ovaries showed the presence of catecholaminergic nerves, identified by their content of immunoreactive tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine biosynthesis. While some of these fibers innervate blood vessels, others are associated with primordial ovarian cells, thereby suggesting their participation in non-vascular functions. Since prefollicular ovaries are insensitive to gonadotropins, the results suggest that the developing ovary becomes subjected to direct neurogenic influences before it acquires responsiveness to gonadotropins.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00381883
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  • 40
    Digitale Medien
    Digitale Medien
    The effects of ageing on the morphology and function of the zonae fasciculata and reticularis of the rat adrenal cortex (1992)
    Springer
    Cell & tissue research 270 (1992), S. 265-272 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex ; Ageing ; Steroidogenesis ; Electron microscopy ; Morphometry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The morphological counterpart of the well-known age-dependent marked impairment of glucocorticoid secretion of rat adrenals was investigated by use of morphometric techniques. For this purpose 4-, 8-, 16- and 24-month-old rats were studied. Despite the notable lowering of both basal and ACTH-stimulated production of corticosterone by collagenase-dispersed inner adrenocortical cells, ACTH and corticosterone plasma concentrations displayed significant increases with ageing. Zona fasciculata (ZF) and zona reticularis (ZR) showed a notable hypertrophy in aged rats, which was due to rises in both the average volume and number of their parenchymal cells. The hypertrophy of ZF and ZR cells was in turn associated with increase in the volume of the mitochondrial compartment and proliferation of smooth endoplasmic reticulum, i.e., the two organelles involved in steroid-hormone synthesis. All these morphologic changes, conceivably due to the chronic exposure to high levels of circulating ACTH, are interpreted as a response enabling ZF and ZR to compensate for their age-dependent lowering in glucocorticoid secretion. Stereology also demonstrated that ZF and ZR cells underwent a striking age-related lipid-droplet repletion. Lipid droplets are the intracellular stores of cholesterol esters, the obligate precursors of steroid hormones in rats. This finding is in keeping with the contention that the mechanism underlying the age-dependent decline in rat-adrenal glucocorticoid secretion mainly involves impairments of the utilization of intracellular cholesterol previous to its intramitochondrial transformation to pregnenolone.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00328012
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  • 41
    Digitale Medien
    Digitale Medien
    Characterization of macrophage-like cells in the external layers of human small and large intestine (1992)
    Springer
    Cell & tissue research 270 (1992), S. 273-279 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Macrophages ; Small intestine ; Large intestine ; External muscle layer ; Immunohistochemistry ; Histochemistry ; Electron microscopy ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In the external layers of human small and large intestine macrophage-like cells were characterized by immunohistochemical, histochemical and electronmicroscopical methods. Using immunohistochemistry and a number of monoclonal antibodies, the presence and distribution of phenotypic subpopulations of macrophages were evaluated. In all locations macrophage-like cells were identified with antibody EBM11, which recognizes CD68 antigen, C3bi which recognizes CD11b, and partly with an antibody which recognizes protein 150,95 (CD11c). Macrophage-like cells in the external muscle layer were HLA-DR-positive (expressing the MHC class-II antigen), in contrast to macrophage-like cells in the subserosa and submucosa. Macrophage-like cells in the external muscle layer were mostly acid phosphatase-negative, and at the electron-microscopic level they were found to have features of macrophages: primary lysosomes, coated vesicles and pits. However, very few secondary lysosomes were present. Birbeck granules were not observed. It is concluded that in the external muscle layer of human small and large intestine numerous macrophages of a special type are present. It is discussed whether this cell type plays a role in gastrointestinal motility and/or has an immunological function.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00328013
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  • 42
    Digitale Medien
    Digitale Medien
    Initial formation of cellular intrinsic fiber cementum in developing human teeth (1992)
    Springer
    Cell & tissue research 267 (1992), S. 321-335 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Teeth ; Cementum ; Cementoblasts ; Matrix production ; Electron microscopy ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The present study describes the formative process of the initiation of cellular intrinsic fiber cementum (CIFC) in still growing human teeth. From 29 premolars and molars with incomplete roots developed to 60–90% of their final length, 8 premolars (with roots formed to three quarters of their final length) were selected for electron-microscopic investigation. All teeth were clinically intact and prefixed in Karnovsky's fixative immediately after extraction. Most of them were decalcified in ethylene diaminetetraacetic acid (EDTA), and the apical part of the roots was divided axially into mesial and distal portions that were subdivided in about 5 slices each. Following osmication and embedding in Epon, these blocks were cut for light- and electron-microscopic examination. In addition, 5 teeth with incomplete roots were freed from organic material and processed for scanning electron microscopy. It was found that CIFC-initiation commenced very close to the advancing root edge and resulted in a rapid cementum thickening. Thereafter, appositional growth continued on the already established cementum surface. Large, basophilic and rough endoplasmic reticulum-rich cementoblasts, some of which became cementocytes, were responsible for both fast and slow CIFC-formation. The CIFC-matrix was free of Sharpey's fibers and composed of more or less organized intrinsic collagen fibrils, in part fibril bundles, that ran roughly parallel to the root surface. Initially, the cementum fibrils intermingled with those of the dentinal collagen fibrils, which were not yet mineralized. This boundary subsequently underwent calcification. The development of collagen fibril bundles and their extracellular arrangement were associated with cytoplasmic processes probably involved in fibril formation and fibril assembly. Many cementoblasts contained intracytoplasmic, membrane-bounded collagen fibrils, which probably were related to fibril formation rather than degradation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00302971
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  • 43
    Digitale Medien
    Digitale Medien
    Development of cytoplasmic digitations between Leydig cells and testicular macrophages of the rat (1992)
    Springer
    Cell & tissue research 267 (1992), S. 385-389 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Leydig cells ; Macrophages ; Development, ontogenic ; Electron microscopy ; Testis ; (Rat Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Testicular macrophages and Leydig cells from adult animals are known to be functionally coupled. For example, secreted products from macrophages stimulate testosterone secretion by Leydig cells. In adult rat testes, structural coupling also exists between these cells. This coupling consists of cytoplasmic projections from Leydig cells located within cytoplasmic invaginations of macrophages. Although macrophages are known to exist in the testis in immature animals, it is not known when these digitations develop. The purpose of the present study was to determine whether the time of their development coincides with known maturational events that occur in Leydig cells, particularly during the peripubertal period. Testes from rats at 20, 30 and 40-days-of-age as well as testes from mature rats weighing more than 500 gm were prepared for ultrastructural analysis. It was found that digitations form between 20 and 30-days-of-age. These structures varied from simple tubular projections to complicated branched structures, suggesting that digitations are more than simple invaginations of microvilli into coated vesicles as previously described. Subplasmalemmal linear densities were also observed within macrophages juxtaposed to Leydig cells. Collagen was commonly observed between macrophages and Leydig cells in animals 20 days old. These studies demonstrate that although macrophages are present in the testis in maximal numbers at 20 days-of-age, they do not form junctions with Leydig cells until day 30. This is just prior to the major increase in secretory activity of rat Leydig cells that occurs during puberty.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00302977
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  • 44
    Digitale Medien
    Digitale Medien
    Interstitial cells associated with the deep muscular plexus of the guinea-pig small intestine, with special reference to the interstitial cells of Cajal (1992)
    Springer
    Cell & tissue research 268 (1992), S. 205-216 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Intestine ; Interstitial cells ; Pacemaker ; Electron microscopy ; Guinea-pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Interstitial cells associated with the deep muscular plexus of the guinea-pig small intestine were studied by electron microscopy, and three-dimensional cell models were reconstructed from serial ultrathin sections with a computer graphic system. Three types of cells were recognized. The first type was similar in shape to smooth muscle cells, but did not contain an organized contractile apparatus. Many large gap junctions comprising about 4% of the cell surface were present; they connected cells of the first type to each other, to the second type of cell and to smooth muscle cells of the outer circular layer. The second type of cell had a welldemarcated cell body with long slender processes and was characterized by a large amount of glycogen comprising about 9% of the cell volume. The third type of cell was similar to fibroblasts, and contained well-developed Golgi apparatus and rough endoplasmic retiulum. Some of these fibroblast-like cells (a possible subtype) formed small gap junctions. All three types of cells showed close relationships with nerve varicosities. This cellular network consisting of gap-junction-rich cells, glycogen-rich cells and smooth muscle cells may be involved in the pacemaking activity of intestinal movement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318788
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  • 45
    Digitale Medien
    Digitale Medien
    12-O-tetradecanoylphorbol-13-acetate induces selective desquamation of superficial cells in rat urinary bladder epithelium (1992)
    Springer
    Cell & tissue research 268 (1992), S. 239-245 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Urinary bladder ; Epithelial desquamation ; TPA ; Electron microscopy ; Rat (Donryu)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary 12-O-tetradecanoylphorbol-13-acetate (TPA) is known to affect the proliferation and/or differentiation of several types of cells. We injected TPA directly into the lumen of rat bladder to determine, using scanning and transmission electron microscopy, its effects on the bladder epithelium in vivo. At 1 h after TPA injection (1μg/ml), the superficial cells of the epithelium had changed their morphology, and large spherical vacuoles occupied their cytoplasm. In some areas, the underlying intermediate cells were exposed by the desquamation of the superficial cells. During the next few hours, TPA was excreted from the bladder lumen by voluntary micturition, but the desquamation of the superficial cells proceeded further. All the superficial cells were lost from the luminal surface by 24 h after TPA injection. The changes noted were specific for the superficial cells and were not observed in the intermediate or basal cells. After 24h, part of the epithelium had a three-layer structure, indicating that regeneration was taking place. These results demonstrate that TPA selectively affects and desquamates superficial cells in a short period of time. This experimental system may be useful for studying in vivo cell proliferation and/or differentiation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318792
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  • 46
    Digitale Medien
    Digitale Medien
    Histochemical localization of nucleoside triphosphatase activity in assimilate conducting plant tissue (1992)
    Springer
    Protoplasma 167 (1992), S. 145-151 
    Details
    ISSN: 1615-6102
    Schlagwort(e): ATPase ; UTPase ; Electron microscopy ; Energy-dispersive X-ray microanalysis ; Gomphrena globosa ; Histochemistry ; Hordeum distichon ; Monstera deliciosa ; Phloem
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary For the histochemical localization of nucleoside triphosphatases at the electron microscopic level, prefixed tissues were incubated with lead nitrate in addition to substrate (GOMORI reaction). While ATP and UTP as substrates gave electron-dense reaction products at the plasmalemma of sieve tubes, companion cells and phloem parenchyma cells, and at plasmodesmata in primary pitfields, AMP gave reaction products only at the tonoplast of parenchyma cells. Since electron-dense deposits also occur in cell walls and vacuoles, energy dispersive X-ray microanalysis was used to distinguish between lead deposits and lead-phosphate deposits. The latter were restricted to the symplast. Among the three plant species used, the leaf bundle phloem ofHordeum distichon showed ATPase activity largely restricted to the phloem cells, except for the thickwalled sieve tubes. Some activity also bordered the chloroplasts of the bundle sheath cells. In the C4 plantGomphrena globosa, ATPase and UTPase activities appeared to be the greater in phloem parenchyma cells than in sieve tubes. In the phloem of youngMonstera deliciosa roots, ATPase occurred not only at the plasmalemma of sieve tubes, but also around sieve-tube plastids. When compared with AMP as substrate, it appears that nucleoside triphosphates are the natural substrates of the enzyme(s) in the plasmalemma of sieve tubes and phloem parenchyma cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01403377
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  • 47
    Digitale Medien
    Digitale Medien
    Effects of organic acids on stria vascularis ultrastructure and function in the chinchilla (1992)
    Springer
    European archives of oto-rhino-laryngology and head & neck 249 (1992), S. 168-171 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Cochlea-Stria vascularis ; Electron microscopy ; Endocochlear potential ; Loop diuretics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The purpose of this study was to compare the effects of several organic acids (probenecid, sodium salicylate and penicillin G) on the endocochlear potential (EP) and the ultrastructure of the stria vascularis of the chinchilla with the effects of furosemide on these parameters. chinchillas received 50 mg/kg i.v. doses of probenecid, sodium salicylate or penicillin G, or 25 mg/kg i.v. furosemide. The EP was monitored continuously before and for 60 min afterwards. The stria vascularis was removed at 10-min intervals from animals and from 10 to 60 min after the injection of these agents. Specimens were then processed for transmission electron microscopy. Only furosemide had an effect on the EP, causing a reversible reduction. The reduction of the EP was accompanied by the appearance of edema in the intercellular spaces of the stria vascularis. No significant edema was found after probenecid, sodium salicylate or penicillin G. This was consistent with the finding that none of these latter three agents affected the endocochlear potential.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00183494
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  • 48
    Digitale Medien
    Digitale Medien
    Muscle pathology in idiopathic cricopharyngeal dysphagia (1992)
    Springer
    European archives of oto-rhino-laryngology and head & neck 249 (1992), S. 216-223 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Cricopharyngeal dysphagia ; Muscle biopsy ; Electron microscopy ; Enzyme histochemistry ; Myositis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The structural changes in the cricopharyngeal muscle (CM) were examined ultrastructurally and by enzyme histochemistry in five patients suffering from idiopathic cricopharyngeal dysphagia (ICD). Diagnosis was established by fiberoptic esophagoscopy, esophageal manometry and cineradiography. Cricopharyngeal myotomy was performed with marked improvement in all patients. Intraoperatively, a biopsy was taken from the CM. Additionally, all patients underwent neurological examination for possible generalized muscle disease, and a biopsy was taken from a limb muscle. CM from nine cadavers without known history of dysphagia served as control. The control samples disclosed structural changes which were considered to be pathological in other skeletal muscles, and required that the criteria for CM pathology we modified accordingly. In three patients changes in CM histology suggested specific pathogenesis: one patient had evidence for a generalized myositis but was only symptomatic for dysphagia. Another patient had muscle fiber atrophy and slight inflammation in her CM, possibly due to alcohol abuse. The third patient had loss of CM fibers with replacement by connective tissue enough to cause functional disturbances. In two patients no cause for dysphagia was found in either immunohistochemistry or electron microscopic studies. These results demonstrate the special structural features of the CM and indicate that ICD can have multiple etiologies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00178473
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  • 49
    Digitale Medien
    Digitale Medien
    Extracellular matrix in the rat spiral limbus (1992)
    Springer
    European archives of oto-rhino-laryngology and head & neck 249 (1992), S. 224-230 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Inner ear ; Rat spiral limbus ; Intercellular matrix ; Electron microscopy ; Immunomorphology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The matrix of the spiral limbus is obviously a special form of the intercellular substance. In the present study, the rat's spiral limbus was investigated by electron microscopy after fixation with ruthenium red and tannic acid and immunofluorescence to demonstrate matrix components. Collagen types I, II, V, VI, VII, IX and XI and fibronectin were not observed. Collagen type II and cartilage-specific proteoglycans, however, occurred in large quantities. The basal lamina of interdental cells and inner sulcus cells did not contain any collagen type IV. while the basal lamina of the capillaries had only minor amounts. Laminin and nidogen appeared in large amounts in the basal lamina. After fixation with tannic acid, the matrix between the interdental cells and the capillaries contained 20- to 22-nm-thick single and irregularly running fibrils as well as plaques of a fine granular material. After fixation with ruthenium red, 30-to 60-nm-thick, electron-dense granules occurred and most probably consisted of proteoglycans. These findings indicate that the composition of the matrix of the spiral limbus is similar to that of cartilage but not identical.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00178474
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  • 50
    Digitale Medien
    Digitale Medien
    Neural and infranuclear region changes in outer hair cells in acoustically exposed rabbits (1992)
    Springer
    European archives of oto-rhino-laryngology and head & neck 249 (1992), S. 287-292 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Nerve endings ; Outer hair cells ; Acoustic exposure ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Rabbits were exposed to 100 dB pure-tone sound at 2 kHz for 2 h. Electron microscopy was used to study the relationship between changes in the outer hair cells, afferent nerve endings and efferent nerve endings. There was no relationship found between the degree of changes produced in the afferent nerve endings and that the outer hair cells. However, there was a relationship demonstrable between the degree of changes seen in the efferent nerve endings and the infranuclear region of the outer hair cells. These findings show that acoustic trauma will damage most the infranuclear region of the outer hair cells, while efferent nerve endings are injured next and least affected are afferent nerve endings.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00714495
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  • 51
    Digitale Medien
    Digitale Medien
    Structure and dynamics of adrenal mitochondria following stimulation with corticotropin releasing hormone (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 234 (1992), S. 255-262 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Corticotropin releasing hormone ; Adrenal gland ; Mitochondria ; Sprague-Dawley rat ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The mitochondria of rat adrenals were investigated qualitatively and quantitatively in different functional states of the adrenal cortex. Following stimulation of the animals with corticotropin releasing hormone (CRH), the corticosterone serum levels reached a maximum 1 hour after stimulation with CRH. The amount of inner mitochondrial membrane within the zona fasciculata increased showing a biphasic time course, with a first maximum 2 hours and a second maximum 8 hours after stimulation. In contrast, a significant rise of mitochondrial volume occurred only 24 hours after CRH stimulation. Therefore, the dense vesicularization of mitochondrial cristae may constitute an early process to enhance the steroidogenic capacity of these cells. Within cells of the transition zone between zona glomerulosa and zona fasciculata, we could depict a special type of mitochondria with characteristic crescent-like cristae only seen after stimulation with CRH. This type of mitochondria may represent an intermediate form between mitochondria of zona glomerulosa and zona fasciculata underlining the impressive transformational capacity of adrenocortical mitochondria. After hypophysectomy, zona fasciculata cells contained mitochondria with tubular inner membranes, representing a hypofunctional state. In contrast, the hypofunctional state after hypophysectomy and the hyperfunctional state after stimulation of the adrenal cortex via CRH injection did not appear to correlate with the morphology of mitochondria from the zona reticularis and adrenal medulla.© Willey-Liss, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092340212
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  • 52
    Digitale Medien
    Digitale Medien
    Elastic fibers in the duct system of the rat submandibular salivary gland (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 234 (1992), S. 335-347 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Anatomy and histology ; Basement membrane ; Collagen ; Connective tissue ; Elastic tissue ; Electron microscopy ; Rats ; Submandibular gland ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The submandibular salivary gland originates from the floor of the mouth whose mucosa contains elastic fibers. Therefore, such fibers were sought in the duct system of the derivative organ. In adult rats, light microscopy has indeed revealed fine, circumferential, elastic fibers near the basement membrane of the duct epithelium. In the larger extralobular ducts, they were separated from several layers of longitudinal elastic fibers by a capillary-rich zone sparse in elastic fibers except for fine angular ones. More peripherally, larger angular-appearing fibers were frequently present near the submandibular parasympathetic ganglia in the duct wall. As duct diameter decreased, elastic fiber size and number diminished. Intralobularly, the smaller striated ducts, granular and intercalated ducts, and acini generally lacked such fibers. Electron microscopy of the extraglandular portion of the main duct revealed fibrils extending from both fibroblasts and elastic fibers that were close to the epithelium. Microfibrils coursed from them toward the lamina densa. Anchoring filaments joined the lamina densa to the basal plasma membrane of the epithelium. Elastic fibers also appeared to connect to both capillaries and collagen via finer intermediate structures. These associations might permit dynamic interactions of fibroblasts, fibers, smaller fibrillar components, vasa, and the duct epithelium. This interplay could occur during feeding and grooming when tongue protrusion and neck extension stretch the submandibular duct and the gland itself. As a result, the tensile forces engendered could modify cell geometry and the calibers of the larger ducts' lumens and intercellular spaces, thus affecting the flow and composition of salivary secretion.© Willey-Liss, Inc.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092340305
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  • 53
    Digitale Medien
    Digitale Medien
    Blood cells of the gilthead seabream (Sparus aurata L.): Light and electron microscopic studies (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 234 (1992), S. 161-171 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Blood cells ; Teleosts ; Gilthead seabream ; Sparus aurata ; Light microscopy ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The peripheral blood cells of the gilthead seabream (Sparus aurata L.) were studied by light and transmission and scanning electron microscopic methods. Acidophilic erythroblasts and mature erythrocytes, round, oval, and fusiform thrombocytes, neutrophils, acidophils and basophils, lymphocytes, plasma cells, and monocyte-macrophages were characterized. A comparison of our light and electron microscopic results was carried out. The results were discussed with those for other fish species and the main modifications from the common vertebrate haematological pattern observed being considered.© Willey-Liss, Inc.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1092340203
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  • 54
    Digitale Medien
    Digitale Medien
    Primary culture of human fallopian tube epithelial cells and co-culture of early mouse pre-embryos (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 32 (1992), S. 236-242 
    Details
    ISSN: 1040-452X
    Schlagwort(e): Blastocyst ; Pre-implantation ; EGF ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We have established a monolayer culture system for human fallopian tube epithelial cells. The cells were isolated from tubes using collagenase digestion, and were cultured in Ham's F-10 supplemented with 15% fetal calf serum. The epithelial cells derived from culture were characterized using immunocytochemical staining and electron microscopy. These cells were stained with antikeratin and anti-epithelial membrane antigen, but showed no staining after treatment with antivimentin. Electron microscopy showed many microvilli on the cell surface and tight junctions or desmosomes at areas of cell-cell contact. Cell proliferation was enhanced by epidermal growth factor, but not by fibroblast growth factor, insulin, transferrin, estradiol-17β, or progesterone.The 2-cell ICR mouse pre-embryos were co-cultured for 4 days with tubal epithelial cells (A) (n = 98), in cell-conditioned medium (B) (n = 83), or in medium alone (C) (n = 72). During the first 24 h in culture, for groups A and B, the rates of cleavage to the 4-cell stage were 90.9% and 81.9%, respectively. Cleavage rates in these two groups were significantly higher (P =0.0012, P 〉 0.00001) than in group C (56.9%). After 72 h in culture, the rates of development to the blastocyst stage were significantly higher for groups A and B compared to group C (89.6% and 73.5% vs. 54.5%, P 〉 0.00001, P = 0.0002). These results suggest that factor(s) from tubal epithelial cells may facilitate the development of mouse pre-embryos throughout the pre-implantation stages.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrd.1080320308
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  • 55
    Digitale Medien
    Digitale Medien
    A personal computer based implementation of the maximum-likelihood method of analysis of electron microscope autoradiographs (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 73-86 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Electron microscopy ; Autoradiography ; Maximum-likelihood estimation ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The maximum-likelihood (ML) method for the quantitative analysis of electron-microscopic autoradiographs has been shown to be substantially superior to the conventional crossfire (CF) method. It can generate reliable and accurate tracer concentration estimates with far fewer micrographs and produce valid estimates even at counts low enough to preclude the use of the crossfire method while eliminating the need for special ad hoc treatment of narrow membranous structures as well as the secondary verification of the tracer concentration estimates.Despite these significant advantages, the large computational requirements of the ML method has to date hampered its widespread use. In this paper, we present a new line-integration method that allows us to reduce the computational requirements of the ML method to a point where it becomes feasible to implement it on a small computer system of the type typically available to a laboratory user of EM autoradiography. We present the complete line-integration method for the particular case of EM autoradiography with tritium, and show how it can be adapted to other isotopes.We have constructed a software package that implements the complete maximum-likelihood method on the IBM PC class of machines using our line-integration method. Features of this software package which are of particular importance to the research community are device independence, which makes it usable with a large variety of currently available laboratory equipment, and easy portability of the software and data between different computer systems.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070200108
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  • 56
    Digitale Medien
    Digitale Medien
    Preservation and visualization of molecular structure in detergent-extracted whole mounts of cultured cells (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 130-150 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Electron microscopy ; Scanning electron microscopy ; High resolution ; Cytoskeleton ; Biological specimen preparation ; Cultured cells ; Electrophoresis ; Bifunctional crosslinking reagents ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Today's electron microscopes have a resolution sufficient to resolve supramolecular structures. However, the methods used to prepare biological samples for electron microscopy often limit our ability to achieve the resolution that is theoretically possible. We use whole mounts of detergent-extracted cells grown on Formvar-coated gold grids as a model system to evaluate various steps in the preparation of biological samples for high resolution scanning electron microscopy (SEM)Factors that are important in determining the structure and composition of detergent-extracted cells include the nature of the detergent and the composition of the extraction vehicle. Chelation of calcium is extremely important to stabilize and preserve the cytoskeletal filaments. We have also demonstrated both morphologically and by gel electrophoresis that treatment of cells with bifunctional protein crosslinkers before or during extraction with detergent can significantly enhance the preservation of both proteins and supramolecular structures.The methods used to dry samples are a major determinant of the quality of structural preservation. For cytoskeletons freeze-drying (FD) is superior to critical point-drying (CPD), one reason being that CPD samples have to be dehydrated, thereby causing more shrinkage as compared to FD samples. The high pressures to which samples are exposed during CPD may also cause increased shrinkage, and water contamination during CPD causes severe structural damage. We have obtained the best structural preservation of detergent-extracted and fixed cells by manually plunging them into liquid propane and drying over night in a freeze-drayer.The factor that most limits achievement of high resolution in SEM is the metal coat, which has to be very thin, uniform, and free of grain in order not to hide structures or to create artifactual ones. We have found that sputter-coating with 1-3 nm of tungsten (W) or niobium )Nb( gives extremely fine-grained films as well as satisfactory emission of secondary electrons. These samples can also be examined at high resolution by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The best preservation and visualization of supramolecular structures have been obtained using cryosputtering, in which the samples are freeze-dried and then sputter-coated within the freeze-dryer while still frozen. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070220203
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  • 57
    Digitale Medien
    Digitale Medien
    Quantitative morphology for biologists and computer scientists: I. Computer-aided tutorial for biological stereology (version 1.0) (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 338-346 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Tutorial ; Electron microscopy ; Light microscopy ; Software ; Quantitative morphology ; Stereology ; Morphometry ; Simulations ; Terminology ; Data types ; Sampling ; Hierarchies ; Interpretation of data ; Bio-Matrix Project ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: This paper describes a computer-aided tutorial for biological stereology. Stereology, a type of quantitative morphology, includes a collection of statistical methods that quantify the structural compartments that can be viewed in sections with light and electron microscopy. These methods provide volume, surface, length, shape, and number data, and help define the quantitative relationships among the structural compartments of biological hierarchies. Hierarchies, which connect structural data ranging in size from molecules to organs, serve as a central core to which the data of biological databases can be linked. The tutorial focuses on two objectives. It provides the user primarily interested in using quantitative morphology databases with background information, and offers a set of state-of-the-art tools to researchers wishing to use these methods in the laboratory. The main topics of the tutorial include: introduction to quantitative morphology, symbols/terms, data types, sampling, hierarchies, data interpretation, and utilities. The tutorial runs under the MS-DOS operating system and requires at least an IBM PC AT (or compatible), a color monitor (EGA, VGA), 540 KB of RAM, and 3 MB of hard disk space. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070210409
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  • 58
    Digitale Medien
    Digitale Medien
    Computer assisted data collection for stereology: Rationale and description of point counting stereology (PCS) software (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 347-354 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Quantitative morphology ; Morphometry ; Light microscopy ; Electron microscopy ; PCS System III ; MS-DOS ; UNIX ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The paper describes microcomputer software for point counting stereology. Stereology includes a collection of statistical methods that quantify the images of light and transmission electron microscopy. The methods use test grids placed over images to collect raw data, which includes counts of points, intersections, transections, and profiles. In turn, the counts are included in stereological equations that give estimates of compartmental volumes, surfaces, lengths, or numbers. These parameters describe the composition of a structure in three-dimensional space. The PCS (point counting stereology) System Software III serves as a data collection, storage, and management tool. Users set up point counting protocols without programming, enter data by pressing predefined function (MS-DOS) or alphabetic keys (UNIX), store data in files, select files for analysis, and calculate results as stereological densities. The latest version of the PCS software includes a new user interface and is designed as a research “front end” that can feed data either into the calculation tools of a stereology tutorial (Bolender, 1992, this issue) or into the analysis routines of quantitative morphology databases (Bolender and Bluhm, 1992). © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070210410
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  • 59
    Digitale Medien
    Digitale Medien
    Quantitative aspects of synapses on Golgi-impregnated neurons (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 334-352 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Identified neurons ; Quantification ; Rotating/tilting ; Synaptic contacts ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: With the classical Golgi techniques, numerous types of neurons can be distinguished in the cerebral cortex, each with a specific dendritic geometry and pattern of axonal ramifications. In the present review we describe two techniques which allow quantification of synapses on identified neurons: (1) Golgi-rapid impregnation-gold toning-electron microscopy, and (2) Golgi-Kopsch impregnation-gold toning-electron microscopy in combination with staining of the tissue with ethanolic phosphotungstic acid (E-PTA). Both techniques were applied on neurons in the visual cortex of young and adult rabbits. By means of rotating and tilting specimens in the electron microscope, the nondistinctive ultrastructure of obliquely sectioned synapses can be circumvented, leading to precise estimates of asymmetrical vs. symmetrical synapses without complete reconstruction of the neuron. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070230408
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  • 60
    Digitale Medien
    Digitale Medien
    Peripheral sensilla of some lower invertebrates: The platyhelminthes and nematoda (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 285-297 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Electron microscopy ; Evolution ; Flatworms ; Nematodes ; Nervous system ; Review ; Sense organs ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The flatworms (Platyhelminthes) and the round worms (Nematoda) are phylexhibiting strikingly different levels of cellular organization. In both, sensilla are composed of the endings of sensory dendrites intercalated into their epidermis.In flatworms, sensilla that penetrate the syncytial epidermis bear sensory processes derived from cilia. In free-living species, the sensory processes more closely resemble motile cilia, while in parasites, greater deviations occur from the classical cilium pattern. Estimates of the function of the various sensilla have been largely arbitrary, and remain based on ultrastructural features.Sensilla in round worms lie below or within a heavy secreted cuticle. Two glia-like cell types occur. The socket cell mediates contact with cuticle and is responsible for cuticular modifications essential for operation of the sensillum. The sheath cell forms a receptor cavity around the sensory processes and regulates its environment. Sensory processes vary greatly from the classical cilium pattern. Absence of a basal body, but preservation of a ciliary necklace, suggests that the latter has a primary importance in sensory transduction. Estimates of function are based largely on ultrastructural features and analogies to arthropod sensilla. Genetic studies with the free-living nematode Caenorhabditis are beginning to demonstrate details of function and development.Speculations on the roles of basal bodies, rootlets, and vesicles and on the significance of recessed sensilla are given. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 26 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070220306
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  • 61
    Digitale Medien
    Digitale Medien
    Phylogeny of the vomeronasal system and of receptor cell types in the olfactory and vomeronasal epithelia of vertebrates (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 1-21 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Cilia ; Microvilli ; Ultrastructure ; Electron microscopy ; Evolution ; Cladistics ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: In this paper, the evolutionary origin of the vomeronasal system as a discrete sensory system separate from olfaction is examined. The presence of a discrete vomeronasal system appears to be a derived character in tetrapods, and its presence in larval amphibians indicates that the system did not arise as a terrestrial adaptation. The vomeronasal system has been lost independently in several taxa, including crocodilians, some bats, cetaceans, and some primates. The presence of microvillar receptor cells in the vomeronasal epithelium appears to be the ancestral condition for tetrapods, and alternative hypotheses concerning the ancestral condition for receptor cell types in the vertebrate olfactory epithelium are discussed. Finally, the possibility that the vomeronasal system is present in some fishes in a form that has not been recognized is discussed in relation to the phylogenetic distribution of receptor cell types in vertebrates. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070230102
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  • 62
    Digitale Medien
    Digitale Medien
    Fine structure of olfactory epithelia of gastropod molluscs (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 307-324 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Sensory ; Chemosensory ; Ultrastructure ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Among gastropod molluscs the chemical senses are most important for location of distant objects. They are used in food finding, locating mates, avoiding predators, trail following, and homing. Chemoreceptors are commonly associated with the oral area, the tentacles, and the osphradium, which lies in the mantle cavity.Most chemosensory neurons are primary sensory neurons, although secondary sensory cells have been reported in the osphradium of some prosobranch gastropods. Most chemosensory organs contain sensory cells with ciliated sensory endings that are in contact with the external environment. Some sensory endings have only microvilli or have no surface elaborations. Cilia on sensory endings are commonly of the conventional type, but some species have modified cilia; some lack rootlets, some have an abnormal microtubular content, and some have paddle-shaped endings. The perikarya of sensory neurons may be within the sensory epithelium, below it, or in ganglia near the sensory surface. In some groups of gastropods there are peripheral ganglia in the olfactory pathway; in others chemosensory axons appear to pass directly to the CNS.Olfactory epithelia of terrestrial pulmonates have modified brush borders with long branching plasmatic processes and a spongy layer of cytoplasmic tubules which extend from the epithelial cells. Sensory endings of the olfactory receptors are entirely within this spongy layer. Aquatic pulmonates may have a similar spongy layer in their olfactory epithelia, but the cilia of sensory endings, as well as motile cilia of epithelial cells, extend well beyond the spongy layer. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 36 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070220402
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  • 63
    Digitale Medien
    Digitale Medien
    The aesthetasc concept: Structural variations of putative olfactory receptor cell complexes in crustacea (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 325-335 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Sensilla ; Electron microscopy ; Sexual dimorphism ; Homology ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The structure of the aesthetascs has been investigated in the prawn Macrobrachium rosenbergii (larvae and juveniles), the opossum shrimp Neomysis integer, the euphausid Meganyctiphanes, and in the water-fleas Daphnia magna and D. longispina. The aesthetascs, that are thought to represent olfactory receptors, exhibit a considerable structural variation, ranging from the well known aesthetascs of higher crustaceans (lobster, crab, crayfish) to the corresponding sensilla found in the water-fleas and the males of opossum shrimps. The two following morphological characteristics of the aesthetascs are thought to indicate an olfactory function: the shape of the cuticular hair that is long and essentially hose-shaped, and the thin, loosely arranged cuticle of at least the outer part of the cuticular hair. The presence of other structural elements such as sensory cells, cilia, and enveloping cells are vital for the olfactory function, but the development is variable, which makes their use in the morphological definition of aesthetascs problematic. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070220403
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  • 64
    Digitale Medien
    Digitale Medien
    Fine structure of olfactory sensilla in myriapods and arachnids (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 372-391 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Olfactory chemoreceptors ; Electron microscopy ; Wall structures ; Sheath cells ; Dendrites ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Structural features of various types of olfactory sensilla are reviewed. (1). Sensilla basiconica which differ in form and size are found on the antennae of centipedes and millipedes. Their walls show longitudinal slits or grooves that either open into the sensillum lumen or do not penetrate the cuticle. In other such sensilla the outer surface is pierced by pores and the inner surface grooved and pocketed. These sensilla are innervated by one to six sensory cells. Their unbranched outer dendritic segments extend to the tip of the sensillum. The sensory cells are surrounded by two or three sheath cells which terminate at the sensillum base or form a continuous tube around the entire length of the outer dendritic segments. (2) Temporal organs of centipides are located between the insertion of the antenna and the ocelli. These sensilla consist of a shallow cuticular ring with a central sensory plate made up by a layer of unperforated cuticle or a capsule with a mushroom-shaped structure inside formed by fibrous-looking cuticle. A dozen sensory cells with unbranched outer dendritic segments innervate each sensillum. They extend toward the sensory cuticle and pass just below it. Numerous sheath cell processes run parallel to the outer dendritic segments up to the sensory cuticle. (3) Thread-like flagella of Pauropoda are found on the antennae. They possess a flexible unperforated cuticular wall. These sensilla contain nine sensory cells surrounded by several sheath cells which form a continuous cytoplasmic tube around the outer dendritic segments. (4) Single-walled sensilla with numerous plugged pores penetrating the cuticular wall occur on the tarsus of the first leg in ticks. Each sensillum is innervated by 4-15 sensory cells. Three sheath cells terminate in the base of the sensillum. (5) Double-walled sensilla with spoke canals are found on the first tarsus of ticks. Their shaft is longitudinally grooved. Pore canals lead inward from the bottom of the grooves and open into vase-shaped chambers. From its base these canals extend into the lumen of the sensillum which contains unbranched outer dendritic segments of 1-2 sensory cells. (6) Single-walled sensilla with pore openings occur on the distal tarsal segments of the first leg of whip spiders. These sensilla are innervated by 40-45 sensory cells. Their unbranched outer dendritic segments fill the shaft lumen and extend partly into the wall pores. Microvillus-shaped sheath cell processes line the inner surface of the cuticular wall. (7) Tarsal organs are located dorsally on the tarsus of all legs and pedipalps of spiders. These sensory organs consist of a cuticular capsule with a dome-shaped projection inside. It is situated on the proximal sidewall of the capsule and possesses 7 pore canals that enclose the dendritic tips of 2-3 sensory cells, giving a total of 20 sensory cells. Each group of dendrites terminating in an individual pore canal is encased by 2 sheath cells. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070220406
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  • 65
    Digitale Medien
    Digitale Medien
    Ultrastructural diagnosis of human pituitary adenomas (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 107-135 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Electron microscopy ; Endocrine neoplasm ; Pituitary adenomas ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Electron microscopy, which has been instrumental in the characterization of normal pituitary cell types, has also played a crucial role in the mirphologic classification pituitary adenomas arising in the presently known 5 cell types, and in the recognition of 3 adenoma types with yet undisclosed cell derivation. This review deals with the application of electron microscopy for study of pituitary adenomas in order to provide specific pathological diagnosis and aid the clinician in selecting appropriate postoperative treatment. In addition to the ultrastructural appearance and diagnostic features of 15 adenoma types, the morphology of hyperplastic proliferations and that of known normal counterparts of various adenoma types are also discussed. Specific morphologic diagnosis of pituitary lesions is important not only for adequate postoperative management of patient, but is also a prerequisite for study of the natural history and biological behaviour of various adenoma types.
    Zusätzliches Material: 36 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070200202
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  • 66
    Digitale Medien
    Digitale Medien
    The ultrstructure of neuronal-pinealocytic interconnections in the monkey pineal (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 124-135 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Pinealocyte ; Pineal-neuron ; Synapses ; Ribbon synapse ; Innervation ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Recent ultrastructural studies of neuronal-pinealocytic interconnections in the monkey pineal are reviewed. The pinealocytes in the adult monkey show almost all of the cytological specializations known in subprimate mammals. Adjacent pinealocytes are functionally coupled through ribbon synapses on cell bodies and gap junctions on cell bodies and cell processes. The pinealocytes receive direct synaptic contacts of nerve fibers with cholinergic terminal morphology. Nerve cells restricted to the central portion of the pineal receive synaptic contacts with more than three different morphologically defined types of nerve terminals. In addition to nerve terminals containing small clear vesicles or vesicles of pleomorphic morphology, a pinealocyte's terminal process containing the synaptic ribbon forms a true synaptic contact on the nerve cell body. The diversity of synapses on these nerve cells strongly suggests multiple origins of these neurons rather than a single peripheral parasympathetic origin. The possible involvement of pineal neurons in an intrinsic circuit that regulates the function of pinealocytes and integrates the neural input from the central as well as the peripheral nervous systems is discussed.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070210205
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  • 67
    Digitale Medien
    Digitale Medien
    Fine structure of the vomeronasal and septal olfactory epithelia and of glandular structures (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 86-97 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Accessory olfactory ; Nasal glands ; Odorant binding protein ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The vomeronasal and septal olfactory organs are two neurosensory structures in the mammalian nasal septum which are poorly understood relative to the main olfactory system. The vomeronasal organ is a paired, blind-ending tubular structure that opens rostrally into the nasal cavity in some species and into the incisive ducts in others. When present in mammals, the septal olfactory organ is an island of olfactory mucosa positioned such that it is in the primary air pathway in the caudal portion of the nasal cavity. Mammalian nasal glands, with a diverse histochemical and ultrastructural morphology, secrete a variety of substances onto the mucosal surface. One of these substances, odorant binding protein, localized in bovine nasal glands and lateral nasal glands of rodents may be important in the capture and conveyance of odorant molecules to olfactory receptors. The objectives of this paper are to present original data while reviewing the literature on the ultrastructure of vomeronasal and septal olfactory neuroepithelia, and of vomeronasal, bovine nasal, and lateral nasal glands. Nasal tissues from pigs, calves, and hamsters were prepared for electron microscopy. Neurosensory epithelia of the porcine vomeronasal organ and the hamster septal olfactory organ are similar to that described for the vomeronasal and septal olfactory organs of other mammals. Bovine nasal and rodent lateral nasal glands consist of subregions which differ morphologically; the most abundant acinar cell type in the bovine nasal gland contains lightly electron dense secretory granules while that of the rodent lateral nasal gland contains both small electron dense and large, electron lucent granules. The porcine vomeronasal gland contains numerous small, dense granules of a diverse morphology. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070230108
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  • 68
    Digitale Medien
    Digitale Medien
    Dynamics of golgi impregnation in neurons (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 264-274 
    Details
    ISSN: 1059-910X
    Schlagwort(e): CNS ; Light microscopy ; Electron microscopy ; Cerebral cortex ; Nerve cell ; Impregnation method ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: This paper describes the early stages of impregnation by the Golgi rapid method in sections and blocks of brain tissue. Aldehyde-fixed and potassium dichromate-treated sections of cerebral cortex were placed on glass slides and coverslipped. The dichromate solution was then replaced by a silver nitrate solution, and events taking place in the section were monitored and time-lapse recorded until the impregnation was interrupted and the sections subsequently prepared for electron microscopy. The tissue blocks, fixed and chromated in the same way, were placed into a silver nitrate solution for 30 min to 24 h and the progress of impregnation compared with the results obtained in the sections on the glass slides.Two basic modes of impregnation were observed, apparently in direct relation to the process of crystallization of silver chromate: crystals of silver chromate growing directly from the surface of the tissue into the nerve cell via its transected plasma membranes, and microcrystalline precipitate of silver chromate spreading into the nerve cell from nucleation centres dispersed in the tissue. The precipitate grows inside the cell as in a preformed channel until the cell has been filled. If the nucleation begins extracellularly, the precipitate extends into the narrow intercellular gaps. Electron microscopy showed that the crystalline precipitate consisted of multilamellar formations containing dense coalesced granules that did not cross plasma or endocellular membrane boundaries. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 38 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070230403
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  • 69
    Digitale Medien
    Digitale Medien
    Comparison of nuclear hydration in boar spermatozoa before and after freeze-thawing: Contrast analysis of cells embedded in bromide-labeled medium (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 249-254 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Electron microscopy ; Water ; Image analysis ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Epon labeled with bromide was used to embed ejaculated and freeze-thawed spermatozoa, with the hypothesis that it replaces most of cell water. Image analysis of relative contrasts between sperm nuclei and the surrounding medium revealed that when used in low concentrations, bromide is mostly absorbed to the nuclear structures. For higher concentrations, the chromatin is saturated, and the increase in contrast can be used to calculate relative differences in the hydration of nuclei. Boar sperm nuclei are more hydrated after freeze-thawing than before. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070210308
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  • 70
    Digitale Medien
    Digitale Medien
    Computer-assisted morphometry: Point, intersection, and profile counting and three-dimensional reconstruction (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 262-270 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Stereology ; Software ; Coordinate geometry ; Volume density, Surface density ; Numerical density ; Serial sections ; Light microscopy ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The use of computers in morphometry can involve (1) automated image analysis, semiautomated image analysis and point, intersection, intercept and profile counts of two-dimensional images on tissue sections with mathematical extrapolation to the third dimension, (2) direct measurement of volumes, surfaces, lengths, and curvature using x,y,z coordinates of serial sectioned images, or (3) stereologic techniques and serial sections which is a combination of 1 and 2 above. Automated and semiautomated image analysis are generally restricted to specimens that are characterized by differential contrast such as interalveolar septa in the lung or histochemically stained mucous granules in pulmonary epithelium. Point, intersection, and profile counts using hand-held, notebook PCs, portable PCs, or standard PCs and MS-DOS - based application programs are extremely efficient, precise, affordable, and convenient methods of quantitating average values of a population. When morphometric measurements of individual structures are required, computer-assisted three-dimensional reconstruction using x,y,z coordinates of the surface outline from serial sections is a tedious yet precise method. We describe a computer program that efficiently estimates mean caliper diameter, volume, and surface area with less than five percent error with five sections per structure. We also describe a program that does digital image subtraction on serial sections, superimposes digitally generated test systems on biological images, and accumulates point, intersection, and profile counts using a Macintosh II series computer. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070210403
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  • 71
    Digitale Medien
    Digitale Medien
    Heat of fusion and lamellar structure of polyethylene single crystal mats (1982)
    Springer
    Colloid & polymer science 260 (1982), S. 564-569 
    Details
    ISSN: 1435-1536
    Schlagwort(e): lin. Polyethylene ; Single crystals ; Heat of Fusion ; DSC ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Recently published results for solution crystallized PE single crystals have shown, that the experimental heat of fusionΔH * is higher, if the solvent is exchanged to silicon oil (oil suspension samples) as compared with dried mats. This has been interpreted by the collapse of the original hollow pyramids during drying, inducing lateral defects within the lamellae. The present investigation does not confirm this unexpected result.ΔH * of dried mats (T c 66 to 91 °C) and of the corresponding oil suspension samples agree within the rather small limits of experimental error. The crystallinities as derived fromΔH *, density or WAXS are in excellent agreement. SEM micrographs of cold fractured dried mats show their spongy macromorphology, but TEM micrographs of stained ultra-thin sections reveal the lamellar morphology of the walls, consisting of curved lamellae and stacked hollow pyramides. If a dried mat is sintered at room temperature, a dense transparent film is obtained with a rather regular stacked morphology of large flat lamellae.ΔH * of these films agrees with that of the original mat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01422587
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  • 72
    Digitale Medien
    Digitale Medien
    Macromolecular transport in the spiral prominence (1982)
    Springer
    European archives of oto-rhino-laryngology and head & neck 236 (1982), S. 41-51 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Prominentia spiralis cochleae ; Meerrettichperoxidase ; Elektronenmikroskopie ; Inner ear spiral prominence ; Horseradish peroxidase ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Transport of macromolecules in the spiral prominence of the guinea pig was studied after perilymphatic and intravenous horseradish peroxidase (HRP) injection. HRP was taken up by the spiral prominence epithelium from the perilymphatic space and in a much higher degree from the endolymphatic space. A highly endocytic ativity was shown by the stroma cells surrounding the spiral prominence vessel. HRP particles were stored in the cytoplasm within vesicles and vacuoles of different sizes and different contrasts. The mode of tracer storage in the spiral prominence epithelium and in the stroma cells from the morphological point of view suggests lysosomal digestion. HRP was transported from the perilymphatic space into the spiral prominence vessel lumen by means of vesicular transport through the vessel wall, while transport of the tracer from the vessel lumen into the perilymphatic space after intravenous injection was not observed.
    Notizen: Zusammenfassung Nach perilymphatischer und intravenöser Applikation von Meerrettichperoxidase wurde der Transport des Makromoleküls in der Prominentia spiralis des Meerschweinchens verfolgt. Die Tracer-Partikelchen wurden aus dem perilymphatischen Raum und vornehmlich jedoch aus dem Ductus cochlearis in das Oberflächenepithel der Prominentia spiralis aufgenommen. Die das Vas prominens umgebenden Stromazellen nahmen relativ viel Meerrettichperoxidase auf, die im Zytoplasma in unterschiedlich großen und unterschiedlich kontrastreichen Vesikeln und Vakuolen abgelagert wurde. Die Art der zytoplasmatischen Ablagerung des Tracers in den Epithelzellen und den Stromazellen spricht vom morphologischen Aspekt her für einen lysosomalen Abbau. Meerrettichperoxidase wurde von der Perilymphe in das Lumen des Vas prominens transportiert. Dieser Transport erfolgte vesikulär durch das Gefäßendothel. Ein Transport des Tracers in umgekehrter Richtung wurde nach intravenöser Applikation nicht beobachtet.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00464056
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  • 73
    Digitale Medien
    Digitale Medien
    Elektronenmikroskopische Befunde am Bindegewebe von Nervus und Ganglion vestibuli bei Morbus Menière (1982)
    Springer
    European archives of oto-rhino-laryngology and head & neck 236 (1982), S. 67-79 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Menière's disease ; Vestibular nerve ; Vestibular ganglion ; Pathologic alterations ; Electron microscopy ; Morbus Menière ; Nervus vestibularis ; Ganglion vestibuli ; Pathologische Veränderungen ; Elektronenmikroskopie
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Vestibularisganglien von 17 Patienten mit einem Morbus Menière wurden nach transtemporaler oder translabyrinthärer Neurektomie elektronenmikroskopisch untersucht. Als Vergleichsmaterial dienten drei Ganglien, die bei anderer Indikation entnommen wurden und vier postmortale Entnahmen von Ohrgesunden. Bei allen Menière-Präparaten zeigten sich am Bindegewebe gleichartige pathologische Veränderungen von unterschiedlich starkem Ausmaß. Sie bestanden in einer Zunahme des Kollagens, wobei sowohl unterschiedliche Kaliber des Faserquerschnittes als auch Veränderungen der Periodizität der Querstreifung beobachtet wurden. Aktive Fibroblasten und reaktive Schwannsche Zellen, die isoliert lagen, keinem Axon zugeordnet waren und deren z. T. hirschgeweihförmig verzweigte, dünne Zellausläufer Kollagenbündel umhüllten, wurden als Zeichen einer noch ablaufenden Kollagenbildung gedeutet. Die Blutgefäße wiesen häufig eine Vervielfachung der Basalmembran auf, die von einem mehrfach breiteren Saum einer homogenen Matrix umgeben war. Die Perizyten waren oft entweder nekrotisch oder teilweise nicht mehr zu beobachten. Die Endothelzellen wiesen in der Regel kein aktives Zytoplasma auf. Sie erschienen teilweise autolytisch. Die pinozytotische Aktivität erwies sich als auffallend verringert. Diese qualitativen Veränderungen im interstitiellen Gewebe könnten auf ein primär lokales pathologisches Geschehen im Bereich des Nerven und des Ganglions hinweisen.
    Notizen: Summary Vestibular ganglia of 17 patients with Menière's disease, obtained by transtemporal or translabyrinthine neurectomy, were studied by electron microscopy. Three ganglia removed because of other disease and four ganglia of normal ears taken post mortem served as controls. The neuronal fibrous tissue of Menière cases showed without exception pathologic changes of various extent. The amount of collagen was increased, whereby different fiber diameters were observed as well as changes in the periodicity of cross banding. Signs of continuing collagen formation were found: active fibroblasts and an increased number of isolated Schwann cells without axons, showing deerhorn-like ramifications which enveloped collagen bundles. The blood vessels were frequently surrounded by multiple basal membranes and broad bands of homogenous matrix. The pericytes were either necrotic or nonexistent. The endothelial cell cytoplasma was usually not in an active state. Sometimes it seemed to be autolytic. The pinocytotic activity was strikingly diminished. These qualitative changes of the interstitial tissue might point to a local pathologic event in the region of the vestibular nerve and ganglion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00464059
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  • 74
    Digitale Medien
    Digitale Medien
    Chordoid sarcoma (extraskeletal myxoid chondrosarcoma) (1982)
    Springer
    Virchows Archiv 399 (1982), S. 61-78 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Chordoid sarcoma ; Chondrosarcoma ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Evaluation of a series of 12 chordoid sarcomas suggests that there is a wider range of histological features in this entity then previously appreciated. Six of the lesions had a typical tumor cell organization and a mixture of cellular and myxoid stromal components, while the remaining cases were atypical because of a more solid growth pattern. Four of the 12 cases, that included both typically myxoid and more cellular examples, had small foci with hyalinized stroma segragating individual or small groups of tumor cells with and without lacunar spaces. Two atypical cases revealed more extensive and obvious chondrocytic differentiation in recurrent or metastatic lesions and in one of these, the histological pattern was that of mesenchymal chondrosarcoma. Ultrastructural examination of three cases revealed fine structural features of both the tumor cell population and extracellular matrix compatible with chondrocytic differentiation. Results of light and electron microscopy of this series of chordoid sarcoma add further support for categorizing this tumor with other malignant chondrocytic neoplasms. It is probable that chordoid sarcoma and extraskeletal myxoid chondrosarcoma represent the same entity and that this lesion has a close histogenetic relationship to mesenchymal chondrosarcoma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00666219
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  • 75
    Digitale Medien
    Digitale Medien
    Adenoma of the human pituitary producing growth hormone and thyrotropin (1982)
    Springer
    Virchows Archiv 395 (1982), S. 59-68 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Adenohypophysis ; Electron microscopy ; Growth hormone ; Immunocytology ; Pituitary adenoma ; Thyroid-stimulating hormone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A pituitary adenoma removed by surgery from a 22-year-old man was studied by histology, immunocytology, transmission electron microscopy and immunoelectron microscopy. Clinically, the patient had acromegaly and euthyroidism with elevated blood GH concentrations. Blood TSH and T4 levels were within the normal range. Histologically, the adenoma was chromophobic and exhibited no PAS, lead hematoxylin, aldehyde thionin or Grimelius silver positivity. By the immunoperoxidase technique GH, β-TSH and α-subunit but no PRL, ACTH, α-endorphin, β-FSH or β-LH were demonstrated in the adenoma cells. Electron microscopy revealed adenoma cells which were similar to TSH cells and showed no resemblance to GH cells of nontumorous pituitaries or GH-secreting tumors. Immunoelectron microscopy demonstrated GH and β-TSH in the secretory granules. It is concluded that pituitary adenomas composed of TSH-like cells may secrete GH, resulting in acromegaly. Production of GH by adenomatous TSH cells cannot be explained on the basis of the one cell- one hormone theory. The question is raised whether bihormonal or multihormonal clones, capable of synthesizing more than one hormone, exist in the human pituitary. These cells are apparently dormant under normal conditions, but in the course of neoplastic transformation may undergo functional dedifferentiation and acquire the ability to produce two or more different hormones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00443484
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  • 76
    Digitale Medien
    Digitale Medien
    Endothelium and “silver lines” (1982)
    Springer
    Virchows Archiv 395 (1982), S. 133-144 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Endothelium ; Permeability ; Electron microscopy ; Electrolytes ; Silver
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The significance of endothelial “silver lines” was studied by TEM in rat aortas after perfusion with glutaraldehyde followed by silver nitrate. Standard TEM technique proved unsatisfactory (coarse silver granules, imprecise localization, artefacts). Exposure of the silver-treated aortas to photographic fixer markedly improved the image of the deposits leaving fine, stable, uniform “residual granules” about 100 Å in diameter. Most of these granules were localized along the intercellular junctions; they also tended to pool in the basement membrane beneath each junction. This image suggests that the Ag+ ions pass through the junction, and react with its contents as well as with the basement membrane beyond it. A scheme is proposed to explain the reaction of Ag+ ions with anions and negatively charged radicals within the junction. It is concluded that the “silver lines” represent not only a histochemical effect, but also the visualization of a transendothelial electrolyte pathway.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00429607
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  • 77
    Digitale Medien
    Digitale Medien
    The ultrastructure of human fibrosing alveolitis (1982)
    Springer
    Virchows Archiv 395 (1982), S. 181-199 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Lung disease ; Electron microscopy ; Interstitial pneumonia ; Fibrosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This report describes the ultrastructural findings in 37 patients who underwent open lung biopsy which yielded diagnoses of fibrosing alveolitis. A spectrum of lesions are categorized for the capillary endothelium and its basement membrane, the interstitial space and its fibrocellular components, and the alveolar epithelium and its basement membrane. The findings typify the different pulmonary cellular reactions to injury. Evidence for cellular regeneration and death in both epithelial and endothelial cell populations include atypical epithelial cell proliferation, capillary basement membrane multilamination, decrease in capillary lumen size and prominent pericytic ensheathment of pulmonary capillaries. Within the interstitium of the lung, proliferation of collagen and elastic fibers are documented, but in addition, abundant myofibroblasts and smooth muscle cells are present. No ultrastructural evidence of immune complex deposition was found in this study. The morphologic findings of fibrosing alveolitis further support the widespread concept that the lung responds to various injuries in a similar manner and undergoes a common reparative response regardless of etiology.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00429611
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  • 78
    Digitale Medien
    Digitale Medien
    Primary sarcoma of the gallbladder (1982)
    Springer
    Virchows Archiv 396 (1982), S. 91-102 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Primary gallblader sarcoma ; Electron microscopy ; Histopathology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Six Swedish cases of primary sarcoma of the gallbladder from the period 1958–1973 and 1 case from 1975 were studied by light and electron microscopy. The literature was reviewed for the period after 1970. Ultrastructural features of sarcoma were investigated in order to exclude poorly differentiated carcinoma. One case was considered to be an embryonal rhabdomyosarcoma, three cases leiomyosarcoma and two were diagnosed as fibrosarcoma. One case, diagnosed as sarcoma of the gallbladder by light microscopy, was omitted because electron microscopical examination revealed a squamous cell carcinoma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00428502
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  • 79
    Digitale Medien
    Digitale Medien
    Arrest and extravasation of neoplastic cells (1982)
    Springer
    Virchows Archiv 396 (1982), S. 73-89 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Human malignant cells ; K-562 cell line ; Vascular arrest ; Endothelial attrition ; Extravasation ; Nude and lasat mice ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The morphological aspects of the arrest and extravasation of malignant cells of human origin (K-562 cell line) in the lungs of athymic (nude) and asplenic-athymic (lasat) mice were studied by electron microscopy examination of serial sections. The specimens were obtained at sequential stages after the sc inoculation into newborn mice of 107 malignant cells. K-562 cells (105) were also injected iv into control groups of nude and lasat mice to assess the influence of the route of inoculation on the in vivo behavior of K-562 cells. Our results demonstrated that K-562 cells were arrested and proliferated within the pulmonary capillaries without the participation of platelets or fibrin. The neoplastic cells extravasated by attrition and penetration of the endothelium (rather than by diapedesis) and continued to proliferate in the interstitial tissue of the lung, developing into neoplastic nodules. Following iv injection, K-562 cells induced the formation of platelet-tumor cell aggregates within the pulmonary capillaries. However, under these conditions, the neoplastic cells did not adhere to the endothelium nor did they proliferate or extravasate. These aggregates were flushed out by the circulation, restoring the permeability of the capillaries.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00428501
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  • 80
    Digitale Medien
    Digitale Medien
    An ultrastructural and morphometric study of bladder tumours (II) (1982)
    Springer
    Virchows Archiv 396 (1982), S. 291-301 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Electron microscopy ; Bladder neoplasms ; Measurement
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Bladder tissues from 3 groups of patients were examined, using the light and electron microscopes (LM and TEM). One group of patients had a history of well-differentiated papillary transitional cell carcinomas and specimens were taken from cystoscopically normal areas. In a second group frank papillary carcinoma was biopsied. Finally, patients with no history of urothelial tumours and a normal cystoscopic appearance were biopsied during investigations for various benign conditions and these served as controls. In tissues from the first two groups certain differences were seen when these were compared to the controls and the frequency of these was significant. Light microscopic examination of 0.5 μ toluidine blue stained sections revealed an increased number of immature, small dark cells in the superficial layer of the epithelium (P〈0.001). Electron microscopic examination showed that in place of the characteristic asymmetric unit membrane of mature superficial cells, the surface was frequently covered with microvilli and the junctional complexes were often atypical. There was an increased number of abnormalities in the basal lamina (P〈0.001). These features were seen in the absence of cystoscopic and light microscopic changes in three out of eight patients with a history of tumours. It is, therefore, suggested that these are the earliest detectable morphological abnormalities in the pre-neoplastic urothelium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00431388
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  • 81
    Digitale Medien
    Digitale Medien
    Ultrastructure of a virilizing ovarian Leydig-cell-tumor (1982)
    Springer
    Virchows Archiv 397 (1982), S. 17-27 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Ovarian tumor ; Hilus cell tumor ; Leydig cell tumor ; Virilism ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of virilizing ovarian hilus cell tumor (Leydig-cell tumor) in a 37 year old female was studied by light and electron microscopy. The ultrastructural features of this rare and almost allways benign tumor are compared with those reported in the literature and with findings in normal and neoplastic interstitial cells of the testis. Tubulovesicular hyperplasia and formation of whorl structures of the endoplasmatic reticulum together with the presence of exocytosis vesicles on the cell surface may be the morphological manifestation of endocrine activity of the tumor. The identity of ultrastructural and optical diffraction characteristics of the crystal inclusions in both cells (hilar and testicular interstitial) favours the assumption of an homology of both cells and their neoplasms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00430890
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  • 82
    Digitale Medien
    Digitale Medien
    Synovial sarcoma arising in an anatomical bursa (1982)
    Springer
    Virchows Archiv 397 (1982), S. 93-101 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Biphasic synovial sarcoma ; Semitendinosus bursa ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In previous studies, the origin of synovial sarcoma directly from synovium has not been satisfactorily established. This case report describes the light and electron microscopic features of a biphasic synovial sarcoma occurring within the popliteal fossa. At surgery, a cystic mass was identified in relationship to the semitendinosus tendon at the anatomical site of the semitendinosus bursa. The tumour originated from the inner surface of the bursa as multiple papillary projections with no evidence of extension beyond the capsule of the bursa. Portions of the synovial surface were hyperplastic but otherwise normal. The findings indicate that biphasic synovial sarcoma can arise directly from synovium and support the hypothesis of a mesenchymal histogenesis for this tumour.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00430896
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  • 83
    Digitale Medien
    Digitale Medien
    Tumor of mesonephric origin in a diverticulum of the urethra (1982)
    Springer
    Virchows Archiv 397 (1982), S. 335-345 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Bladder neoplasm ; Mesonephric origin ; Urethral diverticulum ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of a rare tumor arising in a diverticulum of the urethra was studied. Light microscopy revealed the typical structures of mesonephric tumor with obvious infiltration of the muscularis. Electron microscopic appearance indicated that the tumor cells were immature and not totally characteristic of any tissue of origin. Apart from appearances suggesting rapid growth, cellular inclusions of various appearance were found.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00496574
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  • 84
    Digitale Medien
    Digitale Medien
    Observations on the ultrastructure of human urothelium: The response of normal bladder of elderly subjects to hyperthermia (1982)
    Springer
    Urological research 10 (1982), S. 227-237 
    Details
    ISSN: 1434-0879
    Schlagwort(e): Human ; Bladder urothelium ; Electron microscopy ; Hyperthermia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An electron microscopic study of normal bladder urothelium of elderly subjects treated by hyperthermic perfusions has shown that the tissue responds, sooner or later, in every instance by desquamation. There is no evidence of cell death prior to desquamation although various organelles undergo structural alterations. Mitochondria are especially prone to suffer varying degrees of damage. A short heat shock has revealed differences in the initial response of the thick and thin regions of bladder urothelium known to occur in elderly subjects. After a long, fractionated treatment, regeneration is evident within 3 daysof the end of treatment, and follow-up biopsies have revealed a hyperplastic urothelium within 10 to 12 weeks. The constituent cells show signs of cytodifferentiation at this time but it remains unknown when an ultrastructurally normal urothelium with characteristic cell layers will be restored. The various treatments in this study suggest that the stem cells in the epithelium are unaffected by the levels of hyperthermia employed and that their unimpaired proliferative capacity ensures regeneration of the urothelium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00255928
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  • 85
    Digitale Medien
    Digitale Medien
    The effect of tetraphenylporphinesulfonate (TPPS) on muscle end-plates in mice (1982)
    Springer
    Acta neuropathologica 56 (1982), S. 201-206 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Muscle end-plates ; Porphyric neuropathy ; Electron microscopy ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Motor end-plates were studied in mice at various intervals after a single injection of a synthetic porphyrin, tetraphenylporphinesulfonate (TPPS). Ultrastructurally, excess accumulation of neurofilaments constituted the earliest abnormality. These were followed by atrophy of many nerve terminals and their separation from the postsynaptic area by interposed separation from the postsynaptic area by interposed Schwann cells. Five to 8 months after the injection some postsynaptic areas showed denervation and atrophy. These progressive changes in the nerve terminals were accompanied by secondary changes in the subneural apparatus. Morphometric analysis revealed marked atrophy of the end-plates and significant swelling of preterminal axons. The present findings are suggestive of partial denervation of muscle, occurring after the injection of a synthetic porphyrin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00690636
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  • 86
    Digitale Medien
    Digitale Medien
    Intra-astrocytic glycogen granules and corpora amylacea stain positively for polyglucosans: A cytochemical contribution on the fine structural polymorphism of particulate polysaccharides (1982)
    Springer
    Acta neuropathologica 57 (1982), S. 99-102 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Cytochemistry ; Electron microscopy ; Polyglucosan bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A cytochemical procedure for polysaccharides was carried out on a brain biopsy specimen, the thin-section study of which had shown excess glucogen granules and the corpora amylacea variety of polyglucosan bodies. Both granules and amyloid bodies were stained positively in contrast to the remaining structures of the brain tissue which remained unstained. This demonstrates that β-granules as well as filamentous and amorphous components of amyloid bodies are just different aspects of the polysaccharide molecule. Up to now the same kind of cytochemical evidence has been supplied for Lafora bodies of human material and Lafora-like bodies of rat material. The present study on corpora amylacea of human material shows that amyloid. Lafora, and Lafora-like bodies all behave the same way when stained for polysaccharides.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00685376
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  • 87
    Digitale Medien
    Digitale Medien
    Spongiform-like changes in Alzheimer's disease (1982)
    Springer
    Acta neuropathologica 56 (1982), S. 146-150 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Alzheimer's disease ; Creutzfeldt-Jakob disease ; Spongiform changes ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructural study of the cortex of four patients with sporadic or familial AD, of two agematched controls without dementia, and of one normal pressure hydrocephalus, revealed in all the cases in the neuropil only occasional vacuoles which had a morphology similar to those observed in CJD. The degree of spongiform-like changes was, however, far less prominent than in CJD and considered mild in all the cases examined. Moreover, curled fragments of membranes within the vacuoles were not observed. It is suggested that the mild vacuolization of the neuropil occasionally observed in cortical biopsies of AD is a non-specific finding and cannot be considered a neuropathologic link between AD and CJD.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00690586
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  • 88
    Digitale Medien
    Digitale Medien
    Central neurocytoma (1982)
    Springer
    Acta neuropathologica 56 (1982), S. 151-156 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Central neuronal tumor ; Third ventricle tumor ; Synapses ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The authors report two cases of a rare tumor in adults which were inserted on the fornix and caused a frontal syndrome. By light microscopy, the tumors, highly calcified, were composed of small clear cells forming dense areas in a patchy fibrillary stroma. Electron microscopy revealed a striking neuronal differentiation with numerous synapses. These tumors, for which the term neurocytomas was proposed, were compared with the other CNS neuronal tumors described in the literature.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00690587
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  • 89
    Digitale Medien
    Digitale Medien
    Oculopharyngeal dystrophy: Ultrastructure of muscles distant from the primary myopathy (1982)
    Springer
    Acta neuropathologica 57 (1982), S. 7-12 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Oculopharyngeal muscular dystrophy ; Electron microscopy ; Pectoral and psoas muscles ; Myofibrillar degeneration ; A band fragmentation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The pectoral and psoas muscles from a 72-year-old man afflicted with oculopharyngeal muscular dystrophy were processed at autopsy for electron microscopy. The ultrastructural analyses of the pectoral muscle showed myofibrils which exhibited Z line streaming and a general breakdown in the organization of the sarcomere. In addition, some of the myofibrils displayed sites of degeneration at the center of the A band. The changes in the psoas muscles which are distant from the primary myopathic loci of oculopharyngeal muscular dystrophy were more extensive than that seen in the pectoral muscle. Control tissues showed intact myofibrils and little postmortem alteration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00688872
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  • 90
    Digitale Medien
    Digitale Medien
    Zur Feinstruktur der Nervenendigungen in den Muskelspindeln des M. lumbricalis der Ratte nach Durchschneidung des Nerven (1982)
    Springer
    Acta neuropathologica 57 (1982), S. 23-36 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Muscle spindle ; Electron microscopy ; Nerve endings ; Denervation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The nerve endings in muscle spindles from lumbricalis muscles of the hindpaw of the rat were studied by electron microscopy from 10 h to 7 days after section of the sciatic nerve. No sensory endings were found after 5 days and no motor endings after 3 days. Early changes in sensory endings included accumulation of lamellar bodies, mitochondrial swelling or shrinkage, an edematous appearance of the cytoplasm and disruption of membranes. The predominant way of removal was phagocytosis by activated mesenchymal cells; other endings were incorporated into the sarcoplasm as electrondense bodies. Early changes in motor endings included aggregation or swelling of synaptic vesicles, swelling or shrinkage of mitochondria, edematous change of the cytoplasm and disruption of membranes. The predominant way of removal was incorporation into the cytoplasm of adjacent Schwann cells and degradation to phagolysosomes. Sites of removed sensory endings could be identified by basement membrane reduplication, while the intact subsynaptic apparatus of removed motor endings was either loosely covered by Schwann cell processes, or by fibrillar material, or appeared empty. The differences in the removal of motor and sensory endings are explained by the differences in their anatomic structure.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00688874
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  • 91
    Digitale Medien
    Digitale Medien
    An electron-microscopic study of the brain of the fruit fly,Drosophila melanogaster, exposed to high-LET krypton (84Kr) particle radiation (1982)
    Springer
    Acta neuropathologica 57 (1982), S. 37-44 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Radiation effects ; Nervous system ; Drosophila melanogaster ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Fruit flies (Drosophila melanogaster) were exposed to high-LET krypton (84Kr) ions at low (4.2 rad) and high (1,584 rad) doses and killed to assess acute (36 h post-exposure) and late (35 days post-exposure) effects in the brain by means of electron microscopy. The main findings were: (a) glycogen granules appeared in the neuroglial compartment 36 h after exposure to either dose and were no longer present in flies killed 35 days later, (b) neuronal alterations (swelling and membrane disruption) were observed 35 days after exposure to both doses, (c) changes in the neuroglia (electron-dense masses of concentrically arranged membranous structures) were seen 35 days after exposure. The data are discussed in relation to previous research in the fruit fly using argon (40Ar) charged particles and to other radiation studies performed in the mammalian brain with the view of using the insect brain as a model for detailed study of radiation effects on neurons, neuroglia, and the neuron-neuroglia unit.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00688875
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  • 92
    Digitale Medien
    Digitale Medien
    Hirano bodies in myelinated fibers of hepatic encephalopathy (1982)
    Springer
    Acta neuropathologica 58 (1982), S. 307-310 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Hirano body ; Hepatic encephalopathy ; Oligodendroglia ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Inclusions, essentially identical to Hirano bodies, were observed in the substantia nigra, dentate nuclei, and frontal lobes in three autopsy cases of hepatic encephalopathy. Similar inclusions were not observed in these areas in nine controls. The inclusions were mainly seen in the inner loops of the myelinated fibers, between the myelin lamellae, and among degenerated myelin sheaths. The same inclusions were rarely observed in postsynaptic terminals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00688615
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  • 93
    Digitale Medien
    Digitale Medien
    The permeability alteration of brain and spinal cord vasculature to horseradish peroxidase during experimental decompression sickness as compared to the alteration in permeability induced by hyperosmolar solution (1982)
    Springer
    Acta neuropathologica 57 (1982), S. 179-187 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Decompression sickness ; Hypertonic solutions ; Blood-brain barrier ; Blood-spinal cord barrier ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The permeability of microvasculature in the cerebral cortex, neostriatum, and spinal cord to i. v. injected horseradish peroxidase (HRP) has been investigated in rats following experimental compression to 6.1 bars (abs.) air for 90 min, and subsequent decompression to the ambient pressure in 1 min. For comparison, 1 ml of 2.0 M urea was injected into the right common carotid artery of rats during 15 s. After exposure to compression-decompression, under the light microscope focal leaky areas were found in all the regions examined. The leakage was most prominent in the grey matter of the spinal cord, and the cerebral cortex. In decompressed rats, arterioles were most often the site of peroxidase extravasation, whereas extravasation of HRP was less frequently displayed by capillaries and venules. In urea-treated rats, capillaries and venules frequently displayed extravasation of HRP as well. Parenchymal cells accumulated the trace adjacent to the leaky areas. Under the electron microscope, the extravasation of HRP was associated with peroxidase-containing pleomorphic vesicular structures in the endothelium, both in decompressed and urea-injected rats. Moreover, in contrast to decompressed rats, the junctions between endothelial cells were penetrated by the trace in urea-treated rats. Accordingly, the results indicate that during decompression sickness the pathway for the extravasation of proteins is through vesicular transfer, whereas the injection of hyperosmolar urea induces extravasation, both through vesicular transfer and junctions between the endothelial cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00685387
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  • 94
    Digitale Medien
    Digitale Medien
    Muscle fiber type morphology and distribution in paraplegic patients with traumatic cord lesion (1982)
    Springer
    Acta neuropathologica 57 (1982), S. 243-248 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Skeletal muscle ; Paraplegia ; Complete spinal cord lesion ; Histopatology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Biopsies of the rectus femoris muscle of 22 paraplegic patients with complete acute spinal cord transection due to trauma were taken for enzyme-histochemical and electron-microscopic studies in successive stages starting from the occurrence of the accident (1–17 months). Ingravescent muscular atrophy was demonstrated with a progressive decrease in the fiber diameter and changes in the fiber type distribution with predominant type II atrophy in the first stage and type I atrophy in the later stage of the cord transection. Muscular “neurogenic” changes, such as angular dark atrophic fibers, targetoid fibers, and type predominance are frequently observed. Myopathic alterations are observed in a low percentage in the later stages of the lesion. The ultrastructural findings are characterized by myofibrillar alterations and by dilatation and proliferative phenomena of the sarcoplasmic reticulum and T-system. There are ingravescent accumulation of lipid, interstitial fibrosis and microcirculatory alterations. The possible mechanism of “central” muscle atrophy is reviewed and discussed with reference to the morphological findings.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00692178
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  • 95
    Digitale Medien
    Digitale Medien
    The ultrastructural development of distal nephron segments in the human fetal kidney (1982)
    Springer
    Anatomy and embryology 164 (1982), S. 19-41 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Human kidney ; Nephron development ; Distal segments ; Electron microscopy ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructural development of the human distal nephron was studied in fetuses 14–18 weeks of gestational age. The three-dimensional course of the nephrons was traced in serial semi-thin sections. Single semi-thin sections containing defined distal nephron segments were then reembedded, thin-sectioned and analyzed by electron microscopy. In stage I (renal vesicle) and stage II (S-shaped body) epithelial cells were essentially similar in ultrastructure. In stage III there were only minor variations in cell ultrastructure between distal nephron segments, but distinct differences were observed between proximal and distal tubule cells, the former being the most differentiated. The segments which are present in nephrons of adult kidneys could be identified in stage IV and some ultrastructural differences recognized between the cells. However, the amplification of the baso-lateral membrane, which is prominent in iontransporting mature distal segments, was almost absent and the baso-lateral membrane area per unit tubule length was similar in all distal segments. Intercalated cells were present towards the end of the distal convoluted and in the connecting tubule in stage IV but the ampulla of the collecting tubule was composed of cells with a uniform ultrastructure. Cell ultrastructure varied again to some extent in the collecting tubule. The present observations demonstrate that distal nephron segments in the human kidney are structurally undifferentiated in the early fetal development and suggest that they only to a limited extent are capable of modifying the composition of the tubular fluid.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00301876
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  • 96
    Digitale Medien
    Digitale Medien
    Immunoglobulin production and secretion in bence jones protein myeloma and “nonsecretory” myeloma (1982)
    Springer
    Annals of hematology 45 (1982), S. 121-129 
    Details
    ISSN: 1432-0584
    Schlagwort(e): Multiple myeloma ; Immunoglobulin ; Electron microscopy ; Fluorescent antibody technique
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Using our electron microscopic method for polysome analysis and an immunofluorescent technique we studied Ig production and secretion by tumor cells in seven BJP myeloma patients and seven “nonsecretory” myeloma patients. In BJP myeloma Ig production and secretion is of three types: Type 1, only L-chains are synthesized and secreted; Type 2, the myeloma cells show fluorescence for H-chains, but upon polysome analysis there is no peak at polysomes corresponding to H-chain production; Type 3, the myeloma cells show fluorescence for H-chains, and polysome analysis shows two peaks corresponding to L- and H-chain production. Polysome analysis of “nonsecretory” myelomas show the presence of only very few membrane-bound polysomes and their distribution curves are entirely different from those of “ordinary” myeloma. Furthermore, the distribution patterns vary among seven cases. Results obtained by polysome analysis and immunofluorescent technique suggest that the “nonsecretory” myeloma could be divided into several subtypes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319940
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  • 97
    Digitale Medien
    Digitale Medien
    Tubular aggregates in skeletal muscle of chronic alcoholic patients (1982)
    Springer
    Acta neuropathologica 56 (1982), S. 250-254 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Skeletal muscle ; Chronic alcoholism ; Tubular aggregates ; Histochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The presence of tubular aggregates (TA) in type II muscle fibers in two of 20 alcoholic patients with chronic liver disease, and with no apparent neuromuscular disorder, is reported. The localization, histochemical reactions, and ultrastructural features of the TA are similar to those previously described in other conditions. In one of the two cases TA were demonstrated by E/M observations only and not by histochemistry. No correlations were found between the biochemical changes and the presence of tubular aggregates. We believe that TA are long-standing structures since the muscle biopsies were performed 12 and 13 days after the ingestion of alcohol had been discontinued. They may represent a non-specific response of the sarcoplasmic reticulum to compensate for the deficient calcium uptake reported in alcoholic patients.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00691255
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  • 98
    Digitale Medien
    Digitale Medien
    Cerebrovascular pathogenesis in the telencephalon of the loop-tail mouse: A transmission electron-microscopic study (1982)
    Springer
    Acta neuropathologica 58 (1982), S. 177-182 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Cerebral vessels ; Telencephalon ; Looptail mutant mouse ; Pathogenesis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cerebral capillaries in the telencephalon of normal (+/+;Lp/+)_and abnormal (Lp/Lp) loop-tail mutant mice were studied chronologically by means of electron microscopy at stages ranging from 15 through 18 days of gestation. In the abnormal tissue, neural rosettes were common, and cellular material and red blood cells were often contained within the lumen of the rosettes. The endothelial cells of telencephalic blood vessels in the abnormal brains showed a persistence of cellular projections, subluminal vacuoles, and swollen mitochondria beyond the stage when these features ordinarily disappear in normal embryonic cerebral vessels. The endothelial cells in the abnormal brains also failed to become fully invested with pericytes, and red blood cells gradually infiltrated the neural tissue, particularly in subependymal regions, at 16–18 days of gestation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00690798
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  • 99
    Digitale Medien
    Digitale Medien
    Fine structure of merkel cells after PUVA treatment (1982)
    Springer
    Archives of dermatological research 274 (1982), S. 373-375 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Merkel cell ; PUVA ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00403744
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  • 100
    Digitale Medien
    Digitale Medien
    Ultrastructural evidence for inhibition of chitin synthesis by nikkomycin (1982)
    Springer
    Development genes and evolution 191 (1982), S. 205-207 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Chitin inhibition ; Nikkomycin ; Cuticle ; Electron microscopy ; Epilachna varivestis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The nucleoside antibiotic nikkomycin has proved to be an effective inhibitor of chitin synthesis in the Mexican bean beetleEpilachna varivestis. Ultrastructural investigations show defects in the procuticular area after nikkomycin application which suggest the complete absence of chitin. A cuticle like this is inflexible and too brittle to satisfy its normal function as an exoskeleton. The individuals are not able to free themselves from the exuvia and finally die. Therefore nikkomycin seems to be a potential insecticide with high specifity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848337
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