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  • 1990-1994  (3,494)
  • 1980-1984  (1,709)
  • 1975-1979  (1,543)
  • Engineering General  (5,467)
  • Electron microscopy
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Year
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  • 1
    Electronic Resource
    Electronic Resource
    Widespread aluminium deposition in extracerebral organ systems of patients with dialysis-associated encephalopathy (1994)
    Springer
    Virchows Archiv 424 (1994), S. 105-112 
    Details
    ISSN: 1432-2307
    Keywords: Silver staining ; Aluminium ; Laser microprobe ; Electron microscopy ; Dialysis-associated encephalopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have described new silver-staining methods for the demonstration of lesions in senile dementia of the Alzheimer type. The same procedure was used to visualize characteristic aluminium (Al)-containing inclusions in choroid epithelium, glia and neurons of the central nervous system in dialysis-associated encephalopathy (DAE). Here we describe the patterns and degree of Al deposition in extracerebral tissues of 12 DAE autopsy cases. Light microscopy of silver-stained paraffin sections demonstrated autonomic ganglion cells filled with numerous intracytoplasmic black-stained fine granular inclusions, which were also seen in endocrine tissues (pituitary, parathyroid and adrenal) and in Leydig cells. Heart, liver cells and the testicular tubules were involved, but decalcified bones, haematopoetic elements, hyperplastic epithelium and one case of malignant epithelium lacked inclusions. Laser microprobe mass analysis revealed prominent Al-related mass signals within the en-bloc silver-stained inclusions which were seen at low intensity in adjacent non-stained structures. Electron microscopy demonstrated accumulations of small electron-dense granules intermingling with lipopigments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197400
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  • 2
    Electronic Resource
    Electronic Resource
    Sarcoma of the pulmonary artery: report of four cases with electron microscopic and immunohistochemical examinations, and review of the literature (1994)
    Springer
    Virchows Archiv 424 (1994), S. 217-224 
    Details
    ISSN: 1432-2307
    Keywords: Pulmonary artery ; Neoplasm ; Sarcoma ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Herein we report the clinicopathological features of four cases of pulmonary artery sarcoma that appeared at our institution during a period of 30 years. The patients, 2 males and 2 females, were 50–62 years old. Tumour was found in the pulmonary trunk and right pulmonary artery in all cases, in the pulmonary valve and left pulmonary artery in three of the four cases, and in the right ventricular outflow tract in one case. There was direct extension or metastases to the lungs in two cases, the heart in one case, mediastinum or lymph nodes in two cases and the pleura in one case. Ultrastructural examination in one case revealed cells with features of smooth muscle cells and myofibroblasts. Immunohistochemical examination of three cases gave the following results: vimentin and smooth muscle specific actin was positive in all three cases, desmin in one case and cytokeratin in one case. No positivity was found for Factor VIII. This and other studies indicate that histologically most pulmonary artery sarcomas are leiomyosarcomas or “undifferentiated spindle cell sarcomas”. Immunohistochemical and ultrastructural examinations favour an origin from myofibroblasts, probably derived from multipotent (undifferentiated) cells in the wall of the vessel. Most lesions show extensive intrathoracic growth although they rarely metastasize outside the thoracic cavity. They have a poor prognosis although some cases are currently being diagnosed during life.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193503
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of tissue factor on monocyte-derived macrophages and macrophage foam cells associated with atherosclerotic lesions (1994)
    Springer
    Virchows Archiv 425 (1994), S. 49-54 
    Details
    ISSN: 1432-2307
    Keywords: Thromboplastin ; Atherosclerosis ; Electron microscopy ; Cell culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The expression of tissue factor (TF) antigen by circulating monocytes, cultured macrophages, and macrophages associated with atherosclerotic lesions was ultrastructurally analysed using immunogold labeling. A subpopulation of macrophages associated with the intimal surface overlying lesions had a significant TF expression. Macrophages and macrophage foam cells that projected from the intima into the arterial lumen also expressed a high level of TF (14-fold increase over control). In contrast, circulating monocytes and macrophages in culture did not express TF above background control levels. This TF expression by macrophages in vivo but not by macrophages cultured from either normal or hypercholesterolemic animals suggests that monocyte activation and macrophage transition, as measured by TF expression, is lesion-dependent and not stimulated solely by intimal attachment, surface migration, or hypercholesterolemia. These results further suggest that macrophages and foam cells associated with early lesions of atherosclerosis can initiate fibrin formation, which could contribute to lesion complications and transition to a fibromuscular stage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193948
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  • 4
    Electronic Resource
    Electronic Resource
    Uptake and phototoxic effects of aluminum-chlorophthalocyanine (AISPc) in hurnan bladder carcinoma cells (1994)
    Springer
    Urological research 22 (1994), S. 79-83 
    Details
    ISSN: 1434-0879
    Keywords: Phototoxicity ; Aluminum-chlorophtalocyanine ; Electron microscopy ; DAB staining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In vitro experiments were performed on human bladder carcinoma cells to evaluate the uptake of aluminum-chlorophthalocyanine (AlSPc) and the subcellular target of phototoxicity. In order to quantify the correlation of intracellular uptake and incubation time and to identify the primary subcellular target of phototoxicity, fluorescence and absorption measurements have been carried out as well as electron microscopic studies. Absorption and fluorescence measurements showed the largest value after 24 h of incubation time. Fluorescence microscopic studies suggested the sensitizer to be located in a brighter patch within cytoplasm. Electron microscopic studies using DAB (3,3′ diaminobenzidine) staining showed that the mitochondria are the primary target of phototoxic activity of AlSPc and that the majority of vacuoles of treated cells were originally mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310996
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  • 5
    Electronic Resource
    Electronic Resource
    Madin-Darby canine kidney cells are injured by exposure to oxalate and to calcium oxalate crystals (1994)
    Springer
    Urological research 22 (1994), S. 197-203 
    Details
    ISSN: 1434-0879
    Keywords: MDCK ; Calcium oxalate ; Oxalate ; Scanning ; Electron microscopy ; Trypan blue ; Adenine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The reaction of Madin-Darby canine kidney cells (MDCK) to potassium oxalate (KOx), calcium oxalate monohydrate (COM) crystals, or a combination of the two was studied. The most noticeable effect of exposure of the cells to either KOx or COM crystals was loss of cells from the monolayer ranging from 20% to 30%, depending upon the particular treatment. Cellular enzyme values in the media were elevated significantly by 12h of exposure, although in specific instances, elevated levels occurred at earlier time periods. As regards the monolayer, trypan blue exclusion was decreased significantly, although amounting to only a 4–5% reduction. Specific tritiated release occurred at 4 and 12 h after exposure to KOx and at 12 h after exposure to crystals. Structurally, COM-cell interactions were complex and extensive endocytosis was noted. Cells were released from culture either as cellcrystal complexes or from the intercellular spaces after exocytosis. When treatment were combined the effects were only slightly additive, but the two treatments potentiated each other: all media enzyme levels (with one exception) were elevated at 2 h, tritiated adenine release was present at 4 h, and there was more extensive cell loss from the culture monolayer. These data suggest that both KOx and COM crystals damage MDCK cells when applied alone, and in concert they act synergistically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00541892
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  • 6
    Electronic Resource
    Electronic Resource
    Neuronal vacuole formation in the rat posterior cingulate/retrosplenial cortex after treatment with the N-methyl-d-aspartate (NMDA) antagonist MK-801 (dizocilpine maleate) (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 511-519 
    Details
    ISSN: 1432-0533
    Keywords: Vacuolization ; Neurotoxicity ; Neuropathology ; Electron microscopy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cytoplasmic vacuoles appear in neurons of the posterior cingulate/retrosplenial cortex (PC/RS) of rats after treatment with N-methyl-d-aspartate (NMDA) receptor antagonists. Prominent dilatation of mitochondria and endoplasmic reticulum has been described within 2 h; however, the ultrastructural features of vacuole formation are unknown. To investigate this, the present study examined the PC/RS cortex of male rats (age 60–70 days) at 15, 30, 45, 60, 90, and 120 min after subcutaneous treatment with 1 mg/kg of the noncompetitive NMDA antagonist MK-801 (dizocilpine maleate, 5-methyl-10, 11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine). Subtle mitochondrial dilatation was identified in a few neurons as early as 15 min postdose (MPD). By 30 MPD, dilatation was more pronounced in mitochondria and also involved the endoplasmic reticulum and perinuclear space. Ribosomal disaggregation and degranulation were also evident by 30 MPD. At all subsequent time points, dilatation of mitochondria and endoplasmic reticulum progressed in severity. Although the relative involvement of mitochondria and endoplasmic reticulum varied, glia were not involved. These ultrastructural data suggest that after treatment with MK-801, mitochondrial dilatation precedes involvement of endoplasmic reticulum in vacuolization of susceptible PC/RS cortical neurons. The early mitochondrial effects identified in this study suggest an initial metabolic insult that rapidly progresses to affect endoplasmic reticulum and ribosomes. This strengthens the relationship between the ability of certain NMDA antagonists to induce energy perturbations and neuronal vacuoles in the same region of the rat cerebral cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296487
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  • 7
    Electronic Resource
    Electronic Resource
    Cytoplasmic inclusions of astrocytic elements of glial tumors: special reference to round granulated body and eosinophilic hyaline droplets (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 501-510 
    Details
    ISSN: 1432-0533
    Keywords: Key words Round granulated body ; Eosinophilic ; hyaline droplets ; Astrocytic tumors ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Round granulated body (RGB) and eosinophilic hyaline droplets (EHDs) have been described as cytoplasmic inclusions of certain astrocytic tumors. In the previous literature, however, these inclusions have been described using various terms or regarded as nosologically the same entity. Light microscopically, RGB appeared as a round discrete body filled with fine uniform granules, while EHDs demonstrated a cluster of bright eosinophilic, round objects of various size. They could be clearly distinguished even by conventional histochemical staining such as the Masson trichrome stain and the phosphotungstic acid hematoxylin preparation. Both RGB and EHDs expressed positive immunoreactions for glial fibrillary acidic protein, several lysosomal markers, and some stress-response proteins. The ultrastructural appearances of these inclusions were distinct, however, one common feature was that they consisted of aggregations of numerous membrane-bound electron-dense bodies. Thus, both inclusions appear to be produced by neoplastic astrocytes and are possibly related to the lysosomal system. We examined the presence of RGB and EHDs in 138 astrocytic tumors. Both inclusions occurred most frequently in pleomorphic xanthoastrocytomas, followed by gangliogliomas and pilocytic astrocytomas. Subependymal giant cell astrocytomas exhibited only RGBs. RGBs and EHDs were not seen in any abundance in glioblastomas, gliosarcomas, fibrillary astrocytomas, protoplasmic astrocytomas, or oligo-astrocytomas. Some glioblastomas, however, showed only EHDs in small numbers. Several anaplastic astrocytomas were associated with a large number of RGBs and/or EHDs, and they revealed only rare mitosis despite marked cellular pleomorphism. Although RGB and EHDs have different morphological features, the presence of these inclusions in abundance may represent either a degenerative change, a long-standing lesion, or an indolent growth of the astrocytic tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296486
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  • 8
    Electronic Resource
    Electronic Resource
    Neomyogenesis in neonatally de-efferented and postnatally denervated rat muscle spindles (1994)
    Springer
    Acta neuropathologica 89 (1994), S. 85-95 
    Details
    ISSN: 1432-0533
    Keywords: Key words     Neonatal de-efferentation ; Sensory denervation ; Electron microscopy ; Intrafusal muscle fibre types ; Postnatal myogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract      The ultrastructure of muscle spindles de-efferented by the extirpation of the lumbosacral spinal cord at the age of 2 days and subsequently deprived of their sensory innervation by the section of the sciatic nerve at 3–4 weeks of age was studied in serial sections of 2-month-old rat hindlimb muscles. De-efferentation leaves the primary sensory neurons and their peripheral axons intact and capable of inducing the muscle spindle morphogenesis during the critical period of their development. In de-efferented and subsequently denervated muscle spindles, new supernumerary intrafusal muscle profiles (SIPs) appeared in the muscle spindle A region. They were formed in intimate spatial relation with the original intrafusal muscle fibres (IMFs) predominantly from activated satellite cells derived from both nuclear bag (larger diameter) and nuclear chain fibres. SIPs, however, lacked the typical nuclear accumulations, as well as other ultrastructural distinctions present in control IMFs. The majority of differentiated SIPs separated from original IMFs, whereas the less differentiated SIPs were usually closely apposed to the surface of the parent IMFs and both were covered by the common basal lamina. In some spindles, the original IMFs and/or new SIPs at different stages of their differentiation were found together and they formed clusters of variable shape and composition. In the majority of clusters, all profiles seemed to be isolated along their entire length, although in few clusters, occasional cytoplasmic connections of variable length between intrafusal profiles were found. This result is important for the interpretation of the forthcoming study of expression of muscle spindle-specific myosin heavy chain isoforms in denervated SIPs in rat muscle spindles gradually deprived of their motor and sensory innervation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050219
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  • 9
    Electronic Resource
    Electronic Resource
    Ontogeny of the endocrine cells of the stomach of sea bass (Dicentrarchus labrax L.): an ultrastructural study (1994)
    Springer
    Anatomy and embryology 190 (1994), S. 507-514 
    Details
    ISSN: 1432-0568
    Keywords: Endocrine cells ; Gut ; Ontogeny ; Electron microscopy ; Dicentrarchus labrax (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The endocrine cells present in the developing stomach of sea bass larvae have been characterized ultrastructurally. Only one endocrine cell type (type I) was found in the presumptive stomach of 9- and 12-day-old larvae, one (type II) and five (types III, IV, V, VI and VII) in the aglandular stomach of 32-, and of 39- to 46-day-old larvae, respectively, and five (types III, VIII, IX, X and XI) in the differentiated stomach of 55- and 60-day-old larvae. A maturation process was established for some of these cells. Types I, II and III and types IV and X were thought to be different maturational stages of the same endocrine cell type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235499
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  • 10
    Electronic Resource
    Electronic Resource
    Ontogeny of the endocrine cells of the intestine and rectum of sea bass (Dicentrarchus labrax L.): an ultrastructural study (1994)
    Springer
    Anatomy and embryology 190 (1994), S. 529-539 
    Details
    ISSN: 1432-0568
    Keywords: Endocrine cells ; Gut ; Ontogeny ; Electron microscopy ; Dicentrarchus labrax (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Several endocrine cell types were ultrastructurally characterized during the differentiation of the intestine and rectum of sea bass (Dicentrarchus labrax L.) larvae. Only one cell type (type I) was found in the posterior region of the undifferentiated gut of 5-day-old larvae (phase I). Types V and VI were found in both the intestine and rectum, types II, III and IV in the intestine, and types VII and VIII in the rectum of 9- and 12-day-old larvae (phase II), the rectum alone showing signs of functional differentiation. In phase III larvae, in which both the intestine and rectum were differentiated, types IX, X, XI, XII, XIII, XIV and XV were found in the intestine, only types X, XI and XII being seen in the rectum. Besides these, a new cell type, XVI, was observed in the intestine of 55- and 60-day-old larvae (phase IV), in which the digestive tract was completely differentiated. The endocrine cells appearing in phases I and II showed very scarce secretory granules and the ultrastructural features of undifferentiated cells. Some endocrine cell types in the earliest developmental stages were related to some of those found later. A maturational process of the endocrine cell types paralleled the differentiation of the intestine and rectum, with an apparent increase in the number of secretory granules accompanying organelle development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190103
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  • 11
    Electronic Resource
    Electronic Resource
    Immunocytochemical and ultrastructural studies of the motor cortex in amyotrophic lateral sclerosis (1994)
    Springer
    Acta neuropathologica 87 (1994), S. 578-585 
    Details
    ISSN: 1432-0533
    Keywords: Amyotrophic lateral sclerosis ; Motor cortex ; Betz cells ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report concerns an immunocytochemical and ultrastructural study of the motor cortices of 11 patients with amyotrophic lateral sclerosis (ALS). Specimens from 12 normal individuals served as controls. Antibodies against phosphorylated neurofilament (PNF; 200 kDa), ubiquitin, glial fibrillary acidic protein (GFAP) and phosphorylated tau protein were used. The pyramidal cells of layer III of all ALS patients were stained, with varying intensities, by the antibody to PNF. By contrast, Betz cells reacted less frequently with this antibody. Staining for GFAP was noted in numerous astrocytes in layer III and at the transition between white matter and motor cortex of most patients. Ubiquitin-positive inclusions were only occasionally seen in Betz cell and pyramidal cell of layer V. These observations indicate that alterations of the motor cortex occur first in the pyramidal cells of layer III rather than in Betz cells. Pyramidal cells and Betz cells were not stained by the antibody to phosphorylated tau protein. In controls, pyramidal cells and Betz cells were less frequently stained with the anti-neurofilament antibody than those from ALS patients. Immunoreactivity of GFAP in layer III and at the junction of white matter and motor cortex was observed in only one patient. Ultrastructural examination revealed that the Betz cells of some ALS patients had Bunina bodies (BB), Lewy body-like inclusions (LBI) and skein-like inclusions (SI), as well as bundles of filaments that were thicker than neurofilaments; some of these filaments appeared to be constricted. The incidence of these inclusions was lower than that seen in anterior horn neurons. Cytoplasmic inclusions such as BB, LBI, and SI were not observed in any of the controls. Our findings suggest that the cytopathology of upper motor neurons is similar to that of lower motor neurons and that the changes seen in Betz cells appear to be a reflection of the lower motor neuron alterations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293318
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  • 12
    Electronic Resource
    Electronic Resource
    Astrocytic straight tubules in the brain of a patient with Pick's disease (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 587-591 
    Details
    ISSN: 1432-0533
    Keywords: Astrocytes ; Electron microscopy ; Immunocytochemistry ; Pick's disease ; Straight tubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report concerns an immunohistochemical and ultrastructural study of cerebral astrocytes in a patient with Pick's disease of 20 years' duration. The autopsied brain was prominently small (710 g) with marked fronto-temporal lobar atrophy. Histological examination demonstrated profound neuronal loss and spongy changes with tau-positive Pick bodies in the frontal and temporal cortex. In addition, many glial cells in the temporal lobe white matter contained round to oval, argentophilic and slightly hematoxinophilic cytoplasmic inclusions that were also immunolabeled with the anti-tau antibody. On electron microscopy, the glial inclusions were observed in the perikarya of astrocytes that were recognized as such from intracytoplasmic glial filaments and the presence of gap junctions. The inclusions were free in the cytoplasm, without a limiting membrane, and mainly comprised irregular aggregations of bundles of about 15-nm straight tubules, which were indistinguishable from those of intraneuronal Pick bodies. Furthermore, various patterns of accumulation of the same straight tubules were frequently noted in perivascular astrocytic processes carrying a basal lamina. These findings indicate that in Pick's disease astrocytes are also affected by a similar insult to that which affects neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296498
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  • 13
    Electronic Resource
    Electronic Resource
    Neuronal vacuole formation in the rat posterior cingulate/retrosplenial cortex after treatment with the N -methyl-D-aspartate (NMDA) antagonist MK-801 (dizocilpine maleate) (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 511-519 
    Details
    ISSN: 1432-0533
    Keywords: Key words Vacuolization ; Neurotoxicity ; Neuropathology ; Electron microscopy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cytoplasmic vacuoles appear in neurons of the posterior cingulate/retrosplenial cortex (PC/RS) of rats after treatment with N-methyl-D-aspartate (NMDA) receptor antagonists. Prominent dilatation of mitochondria and endoplasmic reticulum has been described within 2 h; however, the ultrastructural features of vacuole formation are unknown. To investigate this, the present study examined the PC/RS cortex of male rats (age 60 – 70 days) at 15, 30, 45, 60, 90, and 120 min after subcutaneous treatment with 1 mg/kg of the noncompetitive NMDA antagonist MK-801 (dizocilpine maleate, 5-methyl-10, 11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine). Subtle mitochondrial dilatation was identified in a few neurons as early as 15 min postdose (MPD). By 30 MPD, dilatation was more pronounced in mitochondria and also involved the endoplasmic reticulum and perinuclear space. Ribosomal disaggregation and degranulation were also evident by 30 MPD. At all subsequent time points, dilatation of mitochondria and endoplasmic reticulum progressed in severity. Although the relative involvement of mitochondria and endoplasmic reticulum varied, glia were not involved. These ultrastructural data suggest that after treatment with MK-801, mitochondrial dilatation precedes involvement of endoplasmic reticulum in vacuolization of susceptible PC/RS cortical neurons. The early mitochondrial effects identified in this study suggest an initial metabolic insult that rapidly progresses to affect endoplasmic reticulum and ribosomes. This strengthens the relationship between the ability of certain NMDA antagonists to induce energy perturbations and neuronal vacuoles in the same region of the rat cerebral cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296487
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  • 14
    Electronic Resource
    Electronic Resource
    An ultrastructural analysis of human post-infectious (allergic) encephalomyelitis (1994)
    Springer
    Acta neuropathologica 87 (1994), S. 541-544 
    Details
    ISSN: 1432-0533
    Keywords: Allergic Encephalomyelitis ; Astrocytes ; Demyelination ; Electron microscopy ; Multiple sclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 6-year-old boy developed post-infectious encephalomyelitis and underwent a brain biopsy (10 days after the onset of neurologic symptoms). Electron microscopic analysis of brain showed demyelinated axons, thinly myelinated axons, aberrant remyelination, and numerous phagocytes containing myelin debris. Physical stripping of myeling by pseudopodial extensions of macrophages, as reported in experimental allergic encephalomyelitis, was noted. Hypertrophic and hyperplastic astrocytes were prominent among the phagocytic cells and played an unexpectedly active role in demyelination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294183
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  • 15
    Electronic Resource
    Electronic Resource
    Immunocytochemical and ultrastructural studies of the motor cortex in amyotrophic lateral sclerosis (1994)
    Springer
    Acta neuropathologica 87 (1994), S. 578-585 
    Details
    ISSN: 1432-0533
    Keywords: KeyWordsAmyotrophic lateral sclerosis ; Motor cortex Betz cells ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report concerns an immunocytochemical and ultrastructural study of the motor cortices of 11 patients with amyotrophic lateral sclerosis (ALS). Specimens from 12 normal individuals served as con- trols. Antibodies against phosphorylated neurofilament (PNF; 200 kDa), ubiquitin, glial fibrillary acidic protein (GFAP) and phosphorylated tau protein were used. The pyramidal cells of layer III of all ALS patients were stained, with varying intensities, by the antibody to PNF. By contrast, Betz cells reacted less frequently with this antibody. Staining for GFAP was noted in numerous astrocytes in layer III and at the transition between white matter and motor cortex of most patients. Ubiquitin-positive inclusions were only occasionally seen in Betz cell and pyramidal cell of layer V. These observations indicate that alterations of the motor cortex occur first in the pyramidal cells of layer III rather than in Betz cells. Pyramidal cells and Betz cells were not stained by the antibody to phosphorylated tau protein. In controls, pyramidal cells and Betz cells were less frequently stained with the anti-neurofilament antibody than those from ALS patients. Immunoreactivity of GFAP in layer III and at the junction of white matter and motor cortex was observed in only one patient. Ultrastructural examination revealed that the Betz cells of some ALS patients had Bunina bodies (BB), Lewy body-like inclusions (LBI) and skein-like inclusions (SI), as well as bundles of filaments that were thicker than neurofilaments; some of these filaments appeared to be constricted. The incidence of these inclusions was lower than that seen in anterior horn neurons. Cytoplasmic inclusions such as BB, LBI, and SI were not observed in any of the controls. Our findings suggest that the cytopathology of upper motor neurons is similar to that of lower motor neurons and that the changes seen in Betz cells appear to be a reflection of the lower motor neuron alterations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293318
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  • 16
    Electronic Resource
    Electronic Resource
    Generalised nuclear and cytoplasmic inclusion disease: a rare case investigated by microscopy and immunohistochemistry (1994)
    Springer
    Acta neuropathologica 87 (1994), S. 648-654 
    Details
    ISSN: 1432-0533
    Keywords: Inclusion body disease ; Electron microscopy ; Immunohistochemistry ; Viral infection ; Primary metabolic disorder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A Caucasian female who was noted to be mildly microcephalic at birth was diagnosed as having cerebral palsy at the age of 1 year. Her development was delayed and she never walked or talked. She appeared relatively stable neurologically until the age of 17 years when she had an illness with fever thought to be due to a virus. She was noted to deteriorate from this time on until her death at the age of 19 years. Autopsy revealed intranuclear and cytoplasmic inclusions widespread throughout the brain and visceral organs. There was no evidence of inflammation. Immunohistochemistry revealed strong immunoreactivity for tau protein and neurofilament protein. Electron microscopy revealed the inclusions to be composed of homogeneous finely granular material. Scattered with the granular material in the cytoplasmic bodies were crystalline structures with a honeycomb appearance. The possibility of these changes representing an old viral infection or a primary metabolic disorder are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293327
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  • 17
    Electronic Resource
    Electronic Resource
    Light and electron microscopic study of omental milky spots in New Zealand Black mice, with special reference to the extramedullary hematopoiesis (1994)
    Springer
    Anatomy and embryology 189 (1994), S. 215-226 
    Details
    ISSN: 1432-0568
    Keywords: Omental milky spot ; Megakaryocyte ; Myelopoiesis ; Electron microscopy ; New Zealand Black mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Omental milky spots are especially large and numerous in New Zealand Black (NZB) mice, which are known to develop spontaneous autoimmune diseases. We investigated omental milky spots in NZB mice by light and electron microscopy. The milky spots were composed of abundant lymphocytes/plasma cells with macrophages, neutrophils, eosinophils, megakaryocytes, and various stromal cells. In addition, clustered neutrophils in various maturation stages with occasional mitotic figures were frequently present in the milky spots: apparent neutrophilic myelopoiesis was present. The presence of megakaryocytes was sporadic. Considering the giant size of megakaryocytes, their direct migration into the milky spots from the bone marrow or spleen seems improbable. Thus, the presence of megakaryocytes was interpreted as probable megakaryopoiesis. Erythroblasts were not contained in the milky spots. These findings seem to indicate that the milky spots in NZB mice represent a special type of lymphoid tissue with active neutrophilic myelopoiesis and probable megakaryopoiesis. Reticulum cells in the milky spots in NZB mice had well-developed dense bodies consisting of clustered parallel tubules that showed a hexagonal array. However, the biological significance of these cells remains unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239009
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  • 18
    Electronic Resource
    Electronic Resource
    Fiber composition of the lateral plantar and superficial peroneal nerves in the rat foot (1994)
    Springer
    Anatomy and embryology 189 (1994), S. 393-399 
    Details
    ISSN: 1432-0568
    Keywords: Rat ; Myelinated axons ; C-fibers ; Skin ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study examines the fiber composition of two nerves projecting to the rat hindpaw: the lateral plantar nerve (LPN), which innervates plantar glabrous skin and some plantar muscles, and the foot branch of the superficial peroneal nerve (fSPN), which projects to dorsal hairy skin. The LPN contains 872 (33%) myelinated axons with a size range of 1–7 μm and a peak at 4 μm. Some 200 of the myelinated axons are muscle efferents. There are 1,969 (67%) C-fibers. After neonatal capsaicin treatment, the number of C-fibers in the LPN is 61% below the normal level, but it is not significantly different from control levels after chemical sympathectomy with guanethidine. The fSPN is composed of 470 (20%) myelinated axons with a size range similar to that in the LPN. Virtually all myelinated fibers are sensory. There are 1,791 (80%) C-fibers. In neonatally capsaicin-treated animals, the occurrence of C-fibers is 65% below control levels. In chemically sympathectomized animals, the number of C-fibers in the fSPN is normal. This description of the fiber composition of the LPN and the fSPN in the rat provides a basis for future experimental studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00185434
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  • 19
    Electronic Resource
    Electronic Resource
    Astrocytic straight tubules in the brain of a patient with Pick's disease (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 587-591 
    Details
    ISSN: 1432-0533
    Keywords: Key words Astrocytes ; Electron microscopy ; Immunocytochemistry ; Pick's disease ; Straight tubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report concerns an immunohistochemical and ultrastructural study of cerebral astrocytes in a patient with Pick's disease of 20 years' duration. The autopsied brain was prominently small (710   g) with marked fronto-temporal lobar atrophy. Histological examination demonstrated profound neuronal loss and spongy changes with tau-positive Pick bodies in the frontal and temporal cortex. In addition, many glial cells in the temporal lobe white matter contained round to oval, argentophilic and slightly hematoxinophilic cytoplasmic inclusions that were also immunolabeled with the anti-tau antibody. On electron microscopy, the glial inclusions were observed in the perikarya of astrocytes that were recognized as such from intracytoplasmic glial filaments and the presence of gap junctions. The inclusions were free in the cytoplasm, without a limiting membrane, and mainly comprised irregular aggregations of bundles of about 15-nm straight tubules, which were indistinguishable from those of intraneuronal Pick bodies. Furthermore, various patterns of accumulation of the same straight tubules were frequently noted in perivascular astrocytic processes carrying a basal lamina. These findings indicate that in Pick's disease astrocytes are also affected by a similar insult to that which affects neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296498
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  • 20
    Electronic Resource
    Electronic Resource
    Cytoplasmic inclusions of astrocytic elements of glial tumors: special reference to round granulated body and eosinophilic hyaline droplets (1994)
    Springer
    Acta neuropathologica 88 (1994), S. 501-510 
    Details
    ISSN: 1432-0533
    Keywords: Round granulated body ; Eosinophilic hyaline droplets ; Astrocytic tumors ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Round granulated body (RGB) and eosinophilic hyaline droplets (EHDs) have been described as cytoplasmic inclusions of certain astrocytic tumors. In the previous literature, however, these inclusions have been described using various terms or regarded as nosologically the same entity. Light microscopically, RGB apeared as a round discrete body filled with fine uniform granules, while EHDs demonstrated a cluster of bright eosinophilic, round objects of various size. They could be clearly distinguished even by conventional histochemical staining such as the Masson trichrome stain and the phosphotungstic acid hematoxylin preparation. Both RGB and EHDs expressed positive immunoreactions for glial fibrillary acidic protein, several lysosomal markers, and some stress-response proteins. The ultrastructural appearances of these inclusions were distinct, however, one common feature was that they consisted of aggregations of numerous membrane-bound electron-dense bodies. Thus, both inclusions appear to be produced by neoplastic astrocytes and are possibly related to the lysosomal system. We examined the presence of RGB and EHDs in 138 astrocytic tumors. Both inclusions occurred most frequently in pleomorphic xanthoastrocytomas, followed by gangliogliomas and pilocytic astrocytomas. Subependymal giant cell astrocytomas exhibited only RGBs. RGBs and EHDs were not seen in any abundance in glioblastomas, gliosarcomas, fibrillary astrocytomas, protoplasmic astrocytomas, or oligo-astrocytomas. Some glioblastomas, however, showed only EHDs in small numbers. Several anaplastic astrocytomas were associated with a large number of RGBs and/or EHDs, and they revealed only rare mitosis despite marked cellular pleomorphism. Although RGB and EHDs have different morphological features, the presence of these inclusions in abundance may represent either a degenerative change, a long-standing lesion, or an indolent growth of the astrocytic tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296486
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  • 21
    Electronic Resource
    Electronic Resource
    Fine structure of the retinal pigment epithelium in the Port Jackson shark (Heterodontus phillipi) (1994)
    Springer
    Anatomy and embryology 190 (1994), S. 501-506 
    Details
    ISSN: 1432-0568
    Keywords: Retinal pigment epithelium (RPE) ; Electron microscopy ; Elasmobranch ; Heteterodontus phillipi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The structure of the retinal epithelium (RPE), choriocapillaris and Bruch's membrane (complexus basalis) has been studied by light and electron microscopy in the Port Jackson shark (Heterodontus phillipi). In this elasmobranch the RPE consists of a single layer of low cuboidal cells which show basal (scleral) infoldings and apical (vitreal) processes that enclose photoreceptor outer segments. Laterally these epithelial cells are joined by a series of apically located tight junctions. The RPE cells display a large vesicular nucleus, abundant smooth endoplasmic reticulum as well as numerous polysomes and mitochondria. Phagosomes are present, rough endoplasmic reticulum is scarce and myeloid bodies were not observed. Melanosomes are absent over the choroidally located tapetum lucidum, but are not abundant even in extratapetal areas. This paucity of melanosomes probably makes retinomotor movements unimportant. Bruch's membrane or complexus basalis is a pentalaminate structure. The endothelium of the choriocapillaris is thin but minimally fenestrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235498
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  • 22
    Electronic Resource
    Electronic Resource
    Fine structure of the choroidal tapetum lucidum in the Port Jackson shark (Heterodontus phillipi) (1994)
    Springer
    Anatomy and embryology 190 (1994), S. 591-596 
    Details
    ISSN: 1432-0568
    Keywords: Tapetum lucidum ; Electron microscopy ; Elasmobranch ; Heterodontus phillipi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The choroidally located tapetum lucidum of the Port Jackson shark (Heterodontus phillipi) was examined by light and electron microscopy in light-adapted specimens. In this species the tapetum consists of a single layer of overlapping cells oriented at an angle of about 30° to the incoming light and situated immediately external to the choriocapillaris. These tapetal cells alternate with and are separated from one another by melanocytes which extend beyond the tapetal cells to intervene between the tapetal cells and the incoming light. The tapetal cells and the melanocytes are flattened plate-like cells with their widest dimension facing the retina. Internally the tapetal cells display a peripherally located vesicular nucleus with most organelles in a paranuclear location. The bulk of a tapetal cell is packed with regularly spaced crystals reported to be guanine. The size and spacing of these reflective crystals is commensurate with the principles of constructive interference. In light adaptation, the melanosomes of the intervening melanocytes are widely dispersed and for the most part block the passage of light to the tapetal cells. Although dark-adapted specimens were not available, it seems reasonable to assume that in dark adaptation these melanosomes will retreat to unmask the tapetum and allow it to function as a known reflective layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190109
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  • 23
    Electronic Resource
    Electronic Resource
    Distribution of apoptosis-mediating Fas antigen in human skin and effects of anti-Fas monoclonal antibody on human epidermal keratinocyte and squamous cell carcinoma cell lines (1994)
    Springer
    Archives of dermatological research 286 (1994), S. 396-407 
    Details
    ISSN: 1432-069X
    Keywords: Fas antigen ; Immunohistochemical ; Skin disease ; Keratinocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Fast antigen is a cell surface protein that mediates apoptosis. Using immunohistological, flow cytometry and electron microscopic analyses, we investigated the expression of Fas antigen on various skin tissues, and on cultured SV40-transformed human epidermal keratinocyte cell line KJD and human skin squamous cell carcinoma cell line HSC. The Fas antigen was widely distributed in skin components such as the keratinocytes in the lower portion of the epidermis, epidermal dendritic cells, endothelial cells, fibroblasts, apocrine glands, eccrine sweat glands, sebaceous glands, some normal melanocytes and infiltrating lymphoid cells. It was also strongly expressed on the keratinocytes of lichenoid eruptions seen in lupus erythematosus and lichen planus, and on the spongiotic or acanthotic epidermis seen in chronic eczema, adult T-cell leukaemia/lymphoma (ATLL) and atopic dermatitis. Its expression was closely correlated with lymphoid infiltrating cells and it was strongly expressed in lymphoid neoplastic cells, particularly ATLL cells, and fibroblasts seen in dermatofibroma. However, the antigen was not detected on basal cell epithelioma cells, some malignant melanomas or any junctional naevi. The cell lines KJD and HSC strongly expressed the Fas antigen, and crosslinking of the Fas antigen by an anti-Fas monoclonal antibody induced apoptosis of these cell lines. These results indicate that the apoptosis-mediating Fas antigen may play an important role in normal skin turnover and cell differentiation, in immune regulation of skin tumours, and in the pathogenesis of various skin diseases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371800
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  • 24
    Electronic Resource
    Electronic Resource
    Synaptic connectivity of serotonin graft efferents in the suprachiasmatic and supraoptic nuclei of the hypothalamus (1994)
    Springer
    Experimental brain research 101 (1994), S. 353-364 
    Details
    ISSN: 1432-1106
    Keywords: Transplantation ; Serotonin neurons ; Hypothalamus ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have previously reported that a cell suspension from the rostral part of the embryonic raphe grafted to the basal hypothalamus of 5,7-dihydroxytryptamine-denervated rats produced incomplete serotonin (5-HT) re-innervation of the suprachiasmatic nucleus (SCN) as opposed to hyper-innervation of the supraoptic nucleus (SON). We took advantage of this experimental model to investigate whether the graft-derived, 5-HT fibres retained normal ultrastructural features, and, particularly, a normal density of synaptic junctions, irrespective of the extent of target re-innervation. The intrinsic features of immunostained, graft-derived 5-HT axonal varicosities in both the SCN (ventral portion) and the SON were essentially similar to those exhibited by the respective endogenous innervation. Analysis of well-preserved varicosities in uninterrupted series of thin sections allowed us to evaluate directly the proportions of junctional to non-junctional 5-HT varicosities in both regions. Synaptic incidences were also remarkably conserved after grafting (45.5% in the SCN versus 38.5% in the SON; 48% and 38% in normal rats, respectively). Synapses were primarily reestablished on dendritic shafts, which also were identified as the major post-synaptic targets of the normal 5-HT innervations. We noted, however, a tendency toward increased numbers of symmetrical versus asymmetrical synapses in both the SCN and SON of grafted rats. Thus, irrespective of whether hypo-or hyper-innervation patterns developed post-grafting, the transplanted 5-HT neurons essentially retained normal ultrastructural features in their target territories, with a normal incidence of synaptic junctions. The data provide further support to the hypothesis that the innervation territory is the major determinant of the frequency with which ingrowing 5-HT fibres make synaptic junctions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227329
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  • 25
    Electronic Resource
    Electronic Resource
    Ammonium-excreting Azospirillum sp. become intracellularly established in maize (Zea mays) para-nodules (1994)
    Springer
    Biology and fertility of soils 17 (1994), S. 1-8 
    Details
    ISSN: 1432-0789
    Keywords: Ammonium excretion ; Azospirillum brasilense ; Auxine ; 2,4-Dichlor-phenoxy-acetic acid ; Nitrogen fixation ; Paranodulation ; Maize ; Zea mays ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Maize seedlings develop nodule-like tumour knots (para-nodules) along primary roots when treated with the auxin 2,4-dichlor-phenoxy-acetic acid (2,4-D). Inoculated NH 4 + -excreting Azospirillum brasilense cells were shown to colonize these tumours, mostly intracellularly, promoting a high level of N2 fixation when microaerophilic conditions were imposed. The nitrogenase activity inside the para-nodules was less sensitive to free O2 than in non-para-nodulating roots. Both light and electron microscopy showed a dense bacterial population inside intact tumour cells, with the major part of the cell infection along a central tumour tissue. The bacteria colonized the cytoplasm with a close attachment to inner cell membranes. In an auxin-free growth medium, young 2,4-D-induced para-nodules grew further to become mature differentiated root organs in which introduced bacteria survived with a stable population. These results provide evidence that gramineous plants are potentially able to create a symbiosis with diazotrophic bacteria in which the NH 4 + -excreting symbiont will colonize para-nodule tissue intracellularly, thus becoming well protected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00418663
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  • 26
    Electronic Resource
    Electronic Resource
    Ultrastructure of an extreme thermophilic hydrogen-oxidizing bacterium Calderobacterium hydrogenophilum (1994)
    Springer
    Archives of microbiology 162 (1994), S. 267-271 
    Details
    ISSN: 1432-072X
    Keywords: Key words     Extremely thermophilic eubacterium ; Calderobacterium hydrogenophilium ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract       Calderobacterium hydrogenophilum is an extreme thermophilic, obligately chemoautotrophic, hydrogen-oxidizing bacterium. The cells were shown to be non-motile straight rods of average size 0.4 × 2.5 μm. After negative-staining of the whole cells, no flagella were observed. The multilayered cell wall was of type 1 and possessed a crystalline proteinaceous surface layer exhibiting p4 symmetry. The square unit cells had a lattice constant of approximately 11 nm. Cell division occurred by a constriction mechanism. C. hydrogenophilum differred from a similar hydrogen-oxidizing eubacterium, Hydrogenobacter thermophilus, by the absence of intracytoplasmic membrane structures in chemically fixed cells. However, an electron-dense intracytoplasmic hemispherical structure adhering to the inner membrane was frequently observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00301849
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  • 27
    Electronic Resource
    Electronic Resource
    Ultrastructure of an extreme thermophilic hydrogen-oxidizing bacterium Calderobacterium hydrogenophilum (1994)
    Springer
    Archives of microbiology 162 (1994), S. 267-271 
    Details
    ISSN: 1432-072X
    Keywords: Extremely thermophilic eubacterium ; Calderobacterium hydrogenophilium ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Calderobacterium hydrogenophilum is an extreme thermophilic, obligately chemoautotrophic, hydrogen-oxidizing bacterium. The cells were shown to be nonmotile straight rods of average size 0.4x2.5 μm. After negative-staining of the whole cells, no flagella were observed. The multilayered cell wall was of type 1 and possessed a crystalline proteinaceous surface layer exhibiting p4 symmetry. The square unit cells had a lattice constant of approximately 11 nm. Cell division occurred by a constriction mechanism. C. hydrogenophilum differred from a similar hydrogen-oxidizing eubacterium, Hydrogenobacter thermophilus, by the absence of intracytoplasmic membrane structures in chemically fixed cells. However, an electron-dense intracytoplasmic hemispherical structure adhering to the inner membrane was frequently observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00301849
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  • 28
    Electronic Resource
    Electronic Resource
    Membrane topology of insulin receptors reconstituted into lipid vesicles (1994)
    Springer
    The journal of membrane biology 140 (1994), S. 215-223 
    Details
    ISSN: 1432-1424
    Keywords: Insulin receptor ; Membrane reconstitution ; Electron microscopy ; Quaternary structure ; Immunogold labeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Insulin receptors were incorporated into liposomes by two different procedures, one using dialysis and one using detergent removal by Bio-Beads. Receptor incorporation was analyzed by gradient centrifugation and electron microscopy. Reconstituted receptors projected up to 12 nm above the membrane and exhibited a T-shaped structure compatible with that previously described for the solubilized receptor. Insulin binding and autophosphorylation experiments indicated that approx. 50% of the receptors were incorporated right-side out. Such random orientation was confirmed by immunogold labeling of the α- and the β-subunit of the receptor. Immunogold labeling of the C-terminus of the β-subunit indicates that it resides about 6 nm off the membrane, while two α-subunit epitopes were labeled at about twice this distance, confirming that the α-subunit is harbored in the cross-bar of the T-structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233710
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  • 29
    Electronic Resource
    Electronic Resource
    Astrocytes alter their polarity in organotypic slice cultures of rat visual cortex (1994)
    Springer
    Cell & tissue research 277 (1994), S. 557-564 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Slice culture ; Cerebral cortex ; Astrocytes ; Orthogonal arrays of particles - Freeze-fracture ; Electron microscopy ; Rat (Lewis)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The ultrastructure of astrocytes in an organotypic slice culture of the rat visual cortex was investigated using ultrathin sections and freeze-fracture replicas. After a culture period of 9–15 days, a glial scaffold formed that separated the bulk of the slice neuropil from the medium and the underlying plasma clot. However, the glial cells and processes did not build a dense barrier but allowed the outgrowth of neurites. A basal lamina covering the medium-oriented surface of the astrocytes was not found. In freeze-fracture replicas, orthogonal arrays of particles (OAP) were characteristic components of astrocytic membranes. The OAP density in membranes bordering the medium was 35±13 OAP/μm2, corresponding to 2.5% of this membrane area; the OAP density in membranes within the slice neuropil was 22±12 OAP/μm2, corresponding to 1.4% of this membrane area. Although the difference was significant, it was greatly reduced when comparing OAP densities in endfoot and non-endfoot membranes in vivo. Another mode of polarity was recognized in astrocytes of the organotypic slice culture. In membranes of astrocytes bordering upon the medium, the density of non-OAP intramembranous particles (IMP) was clearly higher (1130±136 IMP/μm2) than in membranes of astrocytes in the center of the slice (700±172 IMP/μm2). This pronounced IMP-related polarity was observed neither in vivo nor in cultured astrocytes. The present study suggests, together with data from the literature, that the distribution of astrocytic OAP across the cell surface is influenced by the existence of a basal lamina and neuronal activity, and that astrocytes possess a more remarkable plasticity of membrane structure than previously suspected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300229
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  • 30
    Electronic Resource
    Electronic Resource
    Organization of the endoplasmic reticulum in renal cell lines MDCK and LLC-PK1 (1994)
    Springer
    Cell & tissue research 277 (1994), S. 297-307 
    Details
    ISSN: 1432-0878
    Keywords: Endoplasmic reticulum ; Cellular transport ; Mitochondria ; Electron microscopy ; Contocal microscopy ; MDCK cells ; LLC-PK1 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The spatial organization of the endoplasmic reticulum has been studied in two renal cell lines, MDCK and LLC-PK1, which originate from the distal and proximal portions of the mammalian nephron, respectively, and which form a polarized epithelium when they reach confluence in tissue culture. The two renal cell lines, grown to confluence on either solid or permeable supports, were investigated by fluorescence microscopy, confocal microscopy, and transmission electron microscopy. Fluorescence labeling of the endoplasmic reticulum was achieved using the cationic fluorescent dye DIOC6 (3). In order to differentiate fluorescent labeling of the endoplasmic reticulum from that of the mitochondria, cells were also labeled with rhodamine 123. For electron microscopy, the spatial organization of the endoplasmic reticulum was examined in thick sections using the long-duration osmium impregnation technique or the ferrocyanide/osmium technique. In both cell lines, the endoplasmic reticulum formed an abundant tubular network of canaliculi that frequently abutted the basolateral domain of the plasma membrane and occasionally the apical membrane. Elements of the endoplasmic reticulum were also found in close proximity to mitochondria that, as in the nephron, formed branched structures. Canaliculi appeared circular or flattened and had an inner diameter of 10–70 nm for MDCK cells and 20–90 nm for LLC-PK1 cells. Such a three-dimensional organization might facilitate the translocation of defined lipid species between the endoplasmic reticulum and the plasma membrane, and between the endoplasmic reticulum and mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327777
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  • 31
    Electronic Resource
    Electronic Resource
    Organization of the endoplasmic reticulum in renal cell lines MDCK and LLC-PK1 (1994)
    Springer
    Cell & tissue research 277 (1994), S. 297-307 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Endoplasmic reticulum ; Cellular transport ; Mitochondria ; Electron microscopy ; Confocal microscopy ; MDCK cells ; LLC-PK1 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The spatial organization of the endoplasmic reticulum has been studied in two renal cell lines, MDCK and LLC-PK1, which originate from the distal and proximal portions of the mammalian nephron, respectively, and which form a polarized epithelium when they reach confluence in tissue culture. The two renal cell lines, grown to confluence on either solid or permeable supports, were investigated by fluorescence microscopy, confocal microscopy, and transmission electron microscopy. Fluorescence labeling of the endoplasmic reticulum was achieved using the cationic fluorescent dye DIOC6 (3). In order to differentiate fluorescent labeling of the endoplasmic reticulum from that of the mitochondria, cells were also labeled with rhodamine 123. For electron microscopy, the spatial organization of the endoplasmic reticulum was examined in thick sections using the long-duration osmium impregnation technique or the ferrocyanide/osmium technique. In both cell lines, the endoplasmic reticulum formed an abundant tubular network of canaliculi that frequently abutted the basolateral domain of the plasma membrane and occasionally the apical membrane. Elements of the endoplasmic reticulum were also found in close proximity to mitochondria that, as in the nephron, formed branched structures. Canaliculi appeared circular or flattened and had an inner diameter of 10–70 nm for MDCK cells and 20–90 nm for LLC-PK1 cells. Such a three-dimensional organization might facilitate the translocation of defined lipid species between the endoplasmic reticulum and the plasma membrane, and between the endoplasmic reticulum and mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050156
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  • 32
    Electronic Resource
    Electronic Resource
    Progressive reorganization of the myenteric plexus during one year following reanastomosis of the ileum of the guinea pig (1994)
    Springer
    Cell & tissue research 277 (1994), S. 259-272 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Ileum ; Transection ; Reanastomosis ; Myenteric plexus ; NADH diaphorase histochemistry ; Neuron-specific enolase ; Electron microscopy ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The enteric nervous system appears to play a pivotal role in the functional recovery of the gastrointestinal tract after partial resection and reanastomosis, but the structural changes following surgery are not fully understood. The present study was designed to clarify the processes of myenteric plexus regeneration up to one year after transection and reanastomosis of the ileum of the guinea pig. The following techniques were used: nicotinamide adenine dinucleotide (NADH) diaphorase histochemistry, immunostaining of neuron-specific enolase (NSE) in whole-mount preparations, and transmission electron microscopy. Two months after transection and reanastomosis, myenteric ganglion cells with NADH diaphorase reactions were scarce in the center of the lesion, and were less numerous in adjacent areas (3 mm in width) than in the control ileum. In the areas adjacent to the lesion, a few large extraganglionic neurons that did not completely compensate for the loss of ganglion neurons were observed. The remaining ileum showed no changes in NADH diaphorase staining pattern at this stage. Two to 12 months after transection and reanastomosis, ectopic large neurons gradually increased in number not only in the areas adjacent to the lesion but also in part of the remaining ileum, up to 10 cm from the lesion. Concomitantly, large ganglion neurons decreased in number in these areas. In other ileal regions (more than 10 cm distant from the site of transection), no obvious changes in NADH diaphorase staining were noted throughout the observation period. The outgrowth of NSE-containing nerve fibers from the severed stumps was seen two weeks after transection. Six weeks later, numerous bundles of fine nerve fibers with NSE were shown to interconnect the oral and anal cut ends of the myenteric plexus, but they exhibited no subsequent alterations. Transmission electron microscopy revealed that regenerating nerve fiber bundles appeared initially among irregularly arranged smooth muscle cells eight weeks after the operation, as expected from light-microscopic observations. These findings suggest that myenteric ganglion cell bodies, unlike myenteric nerve fibers, require a longer term of reconstruction than previously believed after transection and reanastomosis of the ileum of the guinea pig.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050153
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  • 33
    Electronic Resource
    Electronic Resource
    Progressive reorganization of the myenteric plexus during one year following reanastomosis of the ileum of the guinea pig (1994)
    Springer
    Cell & tissue research 277 (1994), S. 259-272 
    Details
    ISSN: 1432-0878
    Keywords: Ileum ; Transection ; Reanastomosis ; Myenteric plexus ; NADH diaphorase histochemistry ; Neuron-specific enolase ; Electron microscopy ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The enteric nervous system appears to play a pivotal role in the functional recovery of the gastrointestinal tract after partial resection and reanastomosis, but the structural changes following surgery are not fully understood. The present study was designed to clarify the processes of myenteric plexus regeneration up to one year after transection and reanastomosis of the ileum of the guinea pig. The following techniques were used: nicotinamide adenine dinucleotide (NADH) diaphorase histochemistry, immunostaining of neuron-specific enolase (NSE) in whole-mount preparations, and transmission electron microscopy. Two months after transection and reanastomosis, myenteric ganglion cells with NADH diaphorase reactions were scarce in the center of the lesion, and were less numerous in adjacent areas (3 mm in width) than in the control ileum. In the areas adjacent to the lesion, a few large extraganglionic neurons that did not completely compensate for the loss of ganglion neurons were observed. The remaining ileum showed no changes in NADH diaphorase staining pattern at this stage. Two to 12 months after transection and reanastomosis, ectopic large neurons gradually increased in number not only in the areas adjacent to the lesion but also in part of the remaining ileum, up to 10 cm from the lesion. Concomitantly, large ganglion neurons decreased in number in these areas. In other ileal regions (more than 10 cm distant from the site of transection), no obvious changes in NADH diaphorase staining were noted throughout the observation period. The outgrowth of NSE-containing nerve fibers from the severed stumps was seen two weeks after transection. Six weeks later, numerous bundles of fine nerve fibers with NSE were shown to interconnect the oral and anal cut ends of the myenteric plexus, but they exhibited no subsequent alterations. Transmission electron microscopy revealed that regenerating nerve fiber bundles appeared initially among irregularly arranged smooth muscle cells eight weeks after the operation, as expected from light-microscopic observations. These findings suggest that myenteric ganglion cell bodies, unlike myenteric nerve fibers, require a longer term of reconstruction than previously believed after transection and reanastomosis of the ileum of the guinea pig.
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    URL: http://dx.doi.org/10.1007/BF00327773
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  • 34
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    Electronic Resource
    Astrocytes alter their polarity in organotypic slice cultures of rat visual cortex (1994)
    Springer
    Cell & tissue research 277 (1994), S. 557-564 
    Details
    ISSN: 1432-0878
    Keywords: Slice culture ; Cerebral cortex ; Astrocytes ; Orthogonal arrays of particles ; Freeze-fracture ; Electron microscopy ; Rat (Lewis)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The ultrastructure of astrocytes in an organotypic slice culture of the rat visual cortex was investigated using ultrathin sections and freeze-fracture replicas. After a culture period of 9–15 days, a glial scaffold formed that separated the bulk of the slice neuropil from the medium and the underlying plasma clot. However, the glial cells and processes did not build a dense barrier but allowed the outgrowth of neurites. A basal lamina covering the medium-oriented surface of the astrocytes was not found. In freeze-fracture replicas, orthogonal arrays of particles (OAP) were characteristic components of astrocytic membranes. The OAP density in membranes bordering the medium was 35±13 OAP/μm2, corresponding to 2.5% of this membrane area; the OAP density in membranes within the slice neuropil was 22±12 OAP/μ2, corresponding to 1.4% of this membrane area. Although the difference was significant, it was greatly reduced when comparing OAP densities in endfoot and non-endfoot membranes in vivo. Another mode of polarity was recognized in astrocytes of the organotypic slice culture. In membranes of astrocytes bordering upon the medium, the density of non-OAP intramembranous particles (IMP) was clearly higher (1130±136 IMP/ μm2) than in membranes of astrocytes in the center of the slice (700±172 IMP/μm2). This pronounced IMP-related polarity was observed neither in vivo nor in cultured astrocytes. The present study suggests, together with data from the literature, that the distribution of astrocytic OAP across the cell surface is influenced by the existence of a basal lamina and neuronal activity, and that astrocytes possess a more remarkable plasticity of membrane structure than previously suspected.
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    URL: http://dx.doi.org/10.1007/BF00300229
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  • 35
    Electronic Resource
    Electronic Resource
    Fine structure and lectin histochemistry of the apical surface of the free neuromast of Lampetra japonica (1994)
    Springer
    Cell & tissue research 276 (1994), S. 245-252 
    Details
    ISSN: 1432-0878
    Keywords: Neuromast ; Hair cells ; Surface coat ; Electron microscopy ; Lectin histochemistry ; Lampetra japonica (Cyclostomata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The surface coat, ciliary process, and microvilli of the lamprey neuromast were examined with electron microscopy after tannic acid prefixation and lectin histochemistry. The neuromast was found to exist in the form of a dermal mound with a furrow in the middle. On the bottom of the furrow, the hair cell was characterized by a kinocilium and 15–20 stereocilia, arranged along the longitudinal axis of the furrow. Spanning structures were demonstrated between the kinocilium and stereocilia as well as between stereocilia. The surface coat, enhanced by tannic acid prefixation, was particularly rich over the surface of the supporting cell; by contrast, it was thin over the hair cell. Some lectins (PNA, GS-I, SBA, WGA) showed affinity to the surface coat of the supporting cell as well as the hair cell, and the others (RCA-I, MPA, ConA) showed affinity only to the supporting cell. These differences in the structure and affinities of the surface coat suggest an extracellular milieu highly specialized for the hair cell in this particular form of the mechanoreceptor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306110
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  • 36
    Electronic Resource
    Electronic Resource
    Zona glomerulosa of the adrenal gland in a transgenic strain of rat: a morphologic and functional study (1994)
    Springer
    Cell & tissue research 278 (1994), S. 21-28 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Renin-angiotensin system ; Steroidogenesis ; Electron microscopy ; Morphometry ; Rat, transgenic (mRen2) 27
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Transgenic rats for the murine Ren-2 gene display high blood pressure, low circulating levels of angiotensin II, and high renin content in the adrenal glands. Moreover, transgenic rats possess and increased aldosterone secretion (maximal from 6 to 18 weeks of age), paralleling the development of hypertension. To investigate further the cytophysiology of the adrenal glands of this strain of rats, we performed a combined morphometric and functional study of the zona glomerulosa of 10-week-old female transgenic rats. Morphometry did not reveal notable differences between zona glomerulosa cells of transgenic and age- and sex-matched Sprague-Dawley rats, with the exception of a marked accumulation of lipid droplets, in which cholesterol and cholesterol esters are stored. The volume of the lipid-droplet compartment underwent a significant decrease when transgenic rats were previously injected with angiotensin II or ACTH. Dispersed zona glomerulosa cells of transgenic rats showed a significantly higher basal aldosterone secretion, but their response to angiotensin II and ACTH was similar to that of Sprague-Dawley animals. Angiotensin II-receptor number and affinity were not dissimilar in zona glomerulosa cells of transgenic and Sprague-Dawley rats. These data suggest that the sustained stimulation of the adrenal renin-angiotensin system in transgenic animals causes an increase in the accumulation in zona glomerulosa cells of cholesterol available for steroidogenesis, as indicated by the expanded volume of the lipid-droplet compartment and the elevated basal steroidogenesis. However, the basal hyperfunction of the zona glomerulosa in transgenic animals does not appear to be coupled with an enhanced responsivity to its main secretagogues, at least in terms of aldosterone secretion.
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    URL: http://dx.doi.org/10.1007/BF00305774
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  • 37
    Electronic Resource
    Electronic Resource
    Morphological studies by light and electron microscopy of pancreatic acinar cells under the effect of Tityus serrulatus venom (1994)
    Springer
    Cell & tissue research 278 (1994), S. 255-264 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Scorpion venom ; Exocrine pancreas ; Secretagogue ; Electron microscopy ; Pancreatitis ; cis-Golgi aggregates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. We studied in vivo and in vitro morphological aspects of pancreatic acinar cells after treatment with Tityus serrulatus venom (TSV). After three hours in an in vitro system, positive secretagogue effects of the venom were identifiable both at the light-microscopic (LM) and the electron-microscopic (EM) levels. At 1 μg/ml TSV, maximal secretion (as measured in a concomitant radiolabeling dose-response experiment) of exocrine proteins at 58% was manifest as a discharge of most zymogen granules (ZG) and consequent appearance of secretory material in acinar lumina. At the supramaximal dose of 10 μg/ml TSV, exocytotic images were often observed also with secretory contents previously discharged. The lowest dose of venom at 0.01 μg/ml caused no stimulation of zymogen discharge above resting secretion levels; however, morphological changes were observed. At high doses of TSV, both in vivo and in vitro, large aggregates associated with the cis-Golgi develop between this region and the endoplasmic reticulum (ER). Since Tityus venoms have been associated with causation of pancreatitis, we were interested in comparisons of our experimental tissue with parameters attributed to development of the disease. Our studies have demonstrated considerable evidence that large intracellular vacuoles, discharged ZG, effaced acinar lumina with disappearance of microvilli and other manifestations of possible early events in pancreatitis are indeed frequently observed both in pancreatic lobules in vitro and in whole pancreas in vivo when exposed to TSV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414168
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  • 38
    Electronic Resource
    Electronic Resource
    Zona glomerulosa of the adrenal gland in a transgenic strain of rat: a morphologic and functional study (1994)
    Springer
    Cell & tissue research 278 (1994), S. 21-28 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Adrenal cortex ; Renin-angiotensin system ; Steroidogenesis ; Electron microscopy ; Morphometry ; Rat ; transgenic (mRen2) 27
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Transgenic rats for the murine Ren-2 gene display high blood pressure, low circulating levels of angiotensin II, and high renin content in the adrenal glands. Moreover, transgenic rats possess an increased aldosterone secretion (maximal from 6 to 18 weeks of age), paralleling the development of hypertension. To investigate further the cytophysiology of the adrenal glands of this strain of rats, we performed a combined morphometric and functional study of the zona glomerulosa of 10-week-old female transgenic rats. Morphometry did not reveal notable differences between zona glomerulosa cells of transgenic and age- and sex-matched Sprague-Dawley rats, with the exception of a marked accumulation of lipid droplets, in which cholesterol and cholesterol esters are stored. The volume of the lipid-droplet compartment underwent a significant decrease when transgenic rats were previously injected with angiotensin II or ACTH. Dispersed zona glomerulosa cells of transgenic rats showed a significantly higher basal aldosterone secretion, but their response to angiotensin II and ACTH was similar to that of Sprague-Dawley animals. Angiotensin II-receptor number and affinity were not dissimilar in zona glomerulosa cells of transgenic and Sprague-Dawley rats. These data suggest that the sustained stimulation of the adrenal renin-angiotensin system in transgenic animals causes an increase in the accumulation in zona glomerulosa cells of cholesterol available for steroidogenesis, as indicated by the expanded volume of the lipid-droplet compartment and the elevated basal steroidogenesis. However, the basal hyperfunction of the zona glomerulosa in transgenic animals does not appear to be coupled with an enhanced responsivity to its main secretagogues, at least in terms of aldosterone secretion.
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    URL: http://dx.doi.org/10.1007/BF00305774
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  • 39
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of a growth-associated protein (GAP-43) in rat adrenal gland (1994)
    Springer
    Cell & tissue research 275 (1994), S. 555-566 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal ; Autonomic nervous system ; Schwann cells ; Tyrosine hydroxylase ; GAP-43 ; Electron microscopy ; Immunohistochemistry ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have localized at light and electron-microscopic level the growth-associated protein GAP-43 in adrenal gland using single and double labelling immunocytochemistry. Clusters of GAP-43-immunofluorescent chromaffin cells and many immunofluorescent fibres were observed in the medulla. GAP-43-immunoreactive fibres also formed a plexus under the capsule, crossed the cortex and ramified in the zona reticulata. Double labelled sections showed the coexpression of GAP-43 with a subpopulation of tyrosine hydroxylase-and of dopamine-β-hydroxylase-immunoreactive chromaffin cells. Dual colour immunofluorescence for GAP-43 and calcitonin gene-related peptide (CGRP) revealed that some of the GAP-43-immunoreactive fibres also express CGRP. Pre-embedding electron microscopy showed GAP-43 immunoreactivity associated with the plasma membranes and cytoplasm of noradrenaline-producing chromaffin cells, and with processes of nonmyelin-forming Schwann cells. Immunoreactive unmyelinated axons and terminals were also observed. The immunostained terminals made symmetrical synaptic contacts with chromaffin cells. Immunoreactive unmyelinated fibres and small terminals were present in the cortex. Our results show that GAP-43 is expressed in noradrenergic chromaffin cells and in various types of nerve fibres that innervate the adrenal. Likely origins for these fibres include preganglionic sympathetic fibres which innervate chromaffin cells, postganglionic sympathetic fibres in the cortex, and CGRP containing sensory fibres.
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    URL: http://dx.doi.org/10.1007/BF00318824
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  • 40
    Electronic Resource
    Electronic Resource
    Light- and electron-microscopic study of electrophysiologically characterized neurons in the mediolateral part of the lateral septum of the guinea-pig (1994)
    Springer
    Cell & tissue research 275 (1994), S. 543-553 
    Details
    ISSN: 1432-0878
    Keywords: Lateral septum ; Intracellular injections ; Electron microscopy ; Somatie spines ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In slices of guinea-pig brains, 36 neurons located in the mediolateral part of the lateral septum were stained intracellularly with horseradish peroxidase (n=28) or biocytin (n=8) after electrophysiological characterization. These neurons belonged to class A neurons (n=23), which generated pronounced Ca++-dependent high-threshold spikes in control medium, or to class C neurons (n=9), which were recognized by the occurrence of small-amplitude sodic spikes followed by slower larger calcic spikes. The present results demonstrate that, despite the variety of individual cell types, the major morphological population (30/36 cells) was composed of a homogeneous class of large-sized neurons that displayed thick primary dendrites and abundant dendritic appendages. The remaining 6 cells were small-sized, poorly-spiny neurons. Somatic spines were observed on 5 out of the 30 large cells and on one out of the six smaller cells. Labeled axons were mainly oriented to the anterior commissure. The axons of nine cells richly collateralized near the perikaryon. Ultrastructural examination of 3 horseradish peroxidase-injected cells showed indented nuclei, classic organelles and somatic spines. Terminal boutons established symmetric synapses with the injected cells. These results describe the morphological features of electrophysiologically identified neurons and indicate that class A and class C neurons are distributed among morphological populations differing in perikaryal size. This suggests that the different electrical properties of class A and class C neurons reflect recordings from different parts of the neuron rather than from neurons of different types. Furthermore, the present findings demonstrate that, in the guinea-pig, electrical and morphological characteristics of somatospiny neurons are comparable with those of non-somatospiny neurons. Somatospiny neurons have a recognized integrative role in the hippocampo-septo-hypothalamic complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318823
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  • 41
    Electronic Resource
    Electronic Resource
    Quantitative analysis of rod-cored vesicles and dense granules of large granular lymphocytes in the liver, spleen, and peripheral blood of rats (1994)
    Springer
    Cell & tissue research 276 (1994), S. 187-195 
    Details
    ISSN: 1432-0878
    Keywords: Rod-coredvesicles ; Granules ; Lymphocytes ; Liver ; Electron microscopy ; Rat (Fischer F344/NCR)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Large granular lymphocytes (LGL) comprise a natural defense system in the liver and exert an inhibitory effect on tumor cell metastasis. In order to demonstrate the maturation of LGL in the liver from the morphological aspect, we evaluated electron-microscopically the frequency of 0.2 μm vesicles (rod-cored and “empty” vesicles) and dense granules in LGL from the liver, spleen, and peripheral blood of the rat. Both of these cell organelles are characteristic to LGL and may relate to natural killer-mediated cytolysis. On the average, there were 12.7 of the 0.2 μm vesicles and 4.3 rod-cored vesicles (RCV) per cell section in the liver, 6.6 0.2 μm vesicles and 1.6 RCV in the spleen, and 8.6 0.2 μm vesicles and 0.9 RCV in the peripheral blood. The number of 0.2 μm vesicles per cell section ranged from 0 to 19 with the exception of a few higher instances. Therefore, LGL were divided into vesicle-rich(〉9 0.2 μm vesicles per cell section) and vesicle-poor (〈8 per cell section) populations. Hepatic LGL consisted mainly of a vesicle-rich population while splenic LGL consisted mainly of a vesicle-poor population, and peripheral blood contained equal proportions of both populations. In addition to diversity with regard to the number of 0.2 μm vesicles, LGL obtained from various organs also displayed heterogeneity in the number and size of dense granules. Since the number of dense granules per cell section usually ranged from 1 to 13, LGL were diveded into 2 populations, i.e., LGL with many (〉7 per cell section) granules and those with a few(〈6 per cell section) granules. Specifically, splenic LGL had a few small (average diameter, less than 400 nm) dense granules, while sections of LGL from the liver and peripheral blood displayed many small dense granules and a few large (〉400 nm) ones, respectively, in addition to the populations seen in the spleen. Thus, the present study has demonstrateda difference in the distribution of 0.2 μm vesicles in LGL based on the tissue of origin. The present study has revealed the difference in the distribution of 0.2 μm vesicles of LGL by tissue and indicated that immature LGL are predominant in the spleen, while hepatic LGL are generally more mature as defined by the number of vesicles. These data suggest that the microenvironment of the liver may contribute to the increased expression of these vesicles in LGL.
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    URL: http://dx.doi.org/10.1007/BF00354799
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  • 42
    Electronic Resource
    Electronic Resource
    Localization of GABAA receptors in the rabbit retina (1994)
    Springer
    Cell & tissue research 276 (1994), S. 295-307 
    Details
    ISSN: 1432-0878
    Keywords: GABAA receptors ; Light microscopy ; Electron microscopy ; α1 subunit ; β2/3 subunit ; γ2 subunit ; Immunocytochemistry ; Rabbit (New Zealand)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution of gamma-aminobutyric acidA (GABAA) receptors in the rabbit retina is investigated and compared with the distribution of GABAergic neurons using immunocytochemical methods. Antibodies against the α1, β2/3, and γ2 subunits of the GABAA receptor label subpopulations of bipolar, amacrine and ganglion cells. Double labeling experiments show that the γ2 subunit is colocalized with the α1 and the β2/3 subunits in bipolar, amacrine and ganglion cells. Electron microscopy reveals that in the outer plexiform layer, GABAA receptor immunoreactivity is present on dendrites of cone bipolar cells adjacent to the cone pedicles. Bipolar cell dendrites are also receptor-positive at synapses from interplexiform cells. Some receptor immunoreactivity is found intracellularly in processes of horizontal cells. In the inner plexiform layer, GABAA receptor immunoreactivity is present on both rod bipolar and cone bipolar axon terminals at putative GABAergic input sites. Amacrine and ganglion cell processes in sublamina a and b are also labeled.
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    URL: http://dx.doi.org/10.1007/BF00306115
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  • 43
    Electronic Resource
    Electronic Resource
    Negatively-stained polysomes on rough microsome vesicles viewed by electron microscopy: further evidence regarding the orientation of attached ribosomes (1994)
    Springer
    Cell & tissue research 276 (1994), S. 439-444 
    Details
    ISSN: 1432-0878
    Keywords: Polysomes ; Ribosomes ; Subunits ; Liver ; Electron microscopy ; Negative stain ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Rough microsomes, derived from rough endoplasmic reticulum of rat liver, were studied by electron microscopy after negative staining, to seek further information about the orientation of ribosomal small and large subunits in bound polysomes. Rough microsomal vesicles were fixed with 2% formaldehyde, centrifuged onto electron-microscopic grid membranes, and were then negatively-stained with 2% phosphotungstic acid. In these preparations, viewed with the electron microscope, flattened rough microsomal vesicles with bound polysomes were sometimes discernible, and the individual ribosomes in the polysomes occasionally showed small and large subunits. The small subunits were uniformly oriented toward the inside of the polysomal curve. The large and small subunits appeared to be alongside one another on the membrane, consistent with the orientation that has been described by Unwin and his co-workers. The boundary between the small and large subunits occurred at approximately the same level in the ribosome where inter-ribosomal strands have been described previously in surface views of bound polysomes in positively-stained electron-microscopic tissue sections. This further confirms the identity of the strands as messenger RNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00343942
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  • 44
    Electronic Resource
    Electronic Resource
    Morphological studies by light and electron microscopy of pancreatic acinar cells under the effect of Tityus serrulatus venom (1994)
    Springer
    Cell & tissue research 278 (1994), S. 255-264 
    Details
    ISSN: 1432-0878
    Keywords: Scorpion venom ; Exocrine pancreas ; Secretagogue ; Electron microscopy ; Pancreatitis ; cis-Golgi aggregates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We studied in vivo and in vitro morphological aspects of pancreatic acinar cells after treatment with Tityus serrulatus venom (TSV). After three hours in an in vitro system, positive secretagogue effects of the venom were identifiable both at the light-microscopic (LM) and the electron-microscopic (EM) levels. At 1 μg/ml TSV, maximal secretion (as measured in a concomitant radiolabeling dose-response experiment) of exocrine proteins at 58% was manifest as a discharge of most zymogen granules (ZG) and consequent appearance of secretory material in acinar lumina. At the supramaximal dose of 10 μg/ml TSV, exocytotic images were often observed also with secretory contents previously discharged. The lowest dose of venom at 0.01 μg/ml caused no stimulation of zymogen discharge above resting secretion levels; however, morphological changes were observed. At high doses of TSV, both in vivo and in vitro, large aggregates associated with the cis-Golgi develop between this region and the endoplasmic reticulum (ER). Since Tityus venoms have been associated with causation of pancreatitis, we were interested in comparisons of our experimental tissue with parameters attributed to development of the disease. Our studies have demonstrated considerable evidence that large intracellular vacuoles, discharged ZG, effaced acinar lumina with disappearance of microvilli and other manifestations of possible early events in pancreatitis are indeed frequently observed both in pancreatic lobules in vitro and in whole pancreas in vivo when exposed to TSV.
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  • 45
    Electronic Resource
    Electronic Resource
    Induction and formation ofCochliobolus sativus appressoria (1994)
    Springer
    Protoplasma 178 (1994), S. 34-47 
    Details
    ISSN: 1615-6102
    Keywords: Appressorium ; Cochliobolus sativus ; Electron microscopy ; Thigmotropism ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary GerminatingCochliobolus sativus spores were induced to form appressoria on a variety of artificial surfaces, including replicas of the barley leaf surface. Evidence was obtained for the involvement of chemical and topographic signals during induction of appressorium formation inC. sativus. Germ tube thigmotropism was also observed in vitro. Ultrastructure relevant to appressorium formation was observed, including the germ tube apex, apical swelling of the germ tube apex prior to appressorium formation, the appressorium with associated septation and the penetration peg. Cytochemical probes applied to germlings at the electron microscope level failed to detect α-D-mannan, α-D-glucan, β-D-galactan, D-glcNAc or D-galNAc polymers in the extracellular mucilage associated with the fungal germlings. The ultrastructure of hyphal apices from germlings grown under different nutritional conditions differed with respect to Spitzenkörper morphology, apex shape and in the quantity of associated extracellular mucilage. Experimental findings are discussed relative to current understanding of appressorium induction in more extensively studied systems.
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    URL: http://dx.doi.org/10.1007/BF01404119
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  • 46
    Electronic Resource
    Electronic Resource
    Morphology of sweat glands in determining time of death (1994)
    Springer
    International journal of legal medicine 107 (1994), S. 132-140 
    Details
    ISSN: 1437-1596
    Keywords: Time of death ; Sweat glands ; Immunohistochemistry ; Electron microscopy ; Todeszeit ; Schweißdrüsen Immunhistochemie ; Elektronenmikroskopie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung Diese Untersuchung zeigt postmortale autolytische Veränderungen in der Haut auf zellulärer und subzellulärer Ebene und identifiziert Parameter, welche helfen können, die Zeit des Todes in den ersten Stunden postmortem zu bestimmen. Hautproben von der Beugeseite des Arms wurden, 3, 6, 9 und 12. Stunden nach dem Tode von insgesamt 29 Leichen entnommen (verschiedene Altersklassen, keine Zeichen für Hauterkrankungen, verschiedene Todesursachen). Drei Arten der Untersuchungen wurden durchgeführt: zytochemisch (Hematoxylin-Eosin and Alcian-PAS), immunhistochemisch (S-100, CEA, Cytokeratin, ASM) und ultrastrukturell (Elektronenmikroskopie). Die Elektronenmikroskopie erwies sich als nützlich für die Identifizierung von Transformationen die für jeden chronologischen Schritt spezifisch waren: Reduktion des intrazellulären Glykogens in hellen Zellen und Reduktion der sekretorischen Granula in dunklen Zellen sind typische Zeichen für die erste Phase (3 Stunden) nach dem Tode; mitochondriale Dilatation und Rarifizierung der Cristae in hellen und dunklen Zellen sind typisch für die 2. Phase (6 Stunden); Rarifizierung der Microvilli in dunklen und hellen Zellen sind typisch für die 3. Phase (9 Stunden) und Kernpyknose von dunklen und hellen Zellen ist ein Zeichen der letzten Phase (12 Stunden). Zytochemie und Immunhistochemie sorgen für eine nützliche Information — dies gilt nicht für alle chronologischen Stadien, welche hier einbezogen wurden, aber für individuelle Phasen (3 Stunden für Hematoxylin-Eosin und 6 Stunden für Alcian-PAS). Es ist jedoch besonders wichtig, die Resultate von allen solchen Techniken simultan einzubeziehen, so daß die Frage der exakten Todeszeit innerhalb der ersten 12 Stunden postmortem genauer beantwortet werden kann.
    Notes: Abstract This study demonstrates post-mortem autolytic alterations in the skin at cellular and subcellular levels and identifies parameters which may assist in determining the time of death in the first few hours post-mortem. Serial skin samples from the ventral surface of the arm were taken at intervals of 3, 6, 9 and 12 h after death in 29 subjects of various ages, with no signs of skin disease; causes of death were various. Three types of tests were performed: cytochemical (hematoxylin-eosin and alcian-PAS), immunohistochemical (S-100, CEA, Cytokeratin, ASM) and ultrastructural (electron microscopy). Electron microscopy proved useful for identifying transformations which were found to be specific for each chronological step considered: reduction of intracellular glycogen in clear cells and reduction of secretory granules in dark cells are typcial signs of the first stage (3 h) after death; mitochondrial dilatation and rarefaction of cristae in clear and dark cells are typical of the second stage (6 h); rarefaction of microvilli in dark and clear cells is a sign of the last stage (12 h). Cytochemistry and immunohistochemistry supply useful information — not for all the chronological stage considered here, but for individual phases (3 h for hematoxylin-eosin and 6 h for alcian-PAS). However, it is particularly important to use the results from all such techniques simultaneously, so that the question of the exact time of death within the first 12 h post-mortem may be more accurately answered.
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    URL: http://dx.doi.org/10.1007/BF01225600
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  • 47
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    Electronic Resource
    Slowly progressive changes of the retina and retinal pigment epithelium in briard dogs with hereditary retinal dystrophy (1994)
    Springer
    Documenta ophthalmologica 87 (1994), S. 337-354 
    Details
    ISSN: 1573-2622
    Keywords: Animal model ; Briard dogs ; Electron microscopy ; Photoreceptors ; Retinal degeneration ; Retinal pigment epithelium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Seven eyes from 2 generations of Briard dogs (5 weeks — 7 years old) with congenital night blindness and (in the second generation) impairment of day vision to varying degrees, were examined by light and electron microscopy. Specimens from 4 locations were studied: the central area, the midperiphery of the tapetal area, the upper periphery and the lower periphery. Disorientation of rod outer segment disc membranes was seen in the 5-week-old dog. Large electron-lucent inclusions were found in the RPE at 3.5 months of age. These inclusions occurred most frequently in the central and midperipheral-tapetal areas and seemed to increase in numbers and spread towards the periphery with increasing age. The content of these inclusions is not elucidated. Rod photoreceptor degeneration was apparent from 7 months of age and was most prominent in the peripheral areas. The cones were better preserved. The 7-year-old dog showed reduction of photoreceptors in the central and midperipheral-tapetal areas and almost complete photoreceptor degeneration in the periphery. This dog also showed severe changes of the inner retina in the peripheral fundus. It appears that these Briard dogs suffer from a very slowly progressive retinal degeneration, in which the photoreceptor degenerative changes do not correlate anatomically to the changes in the RPE cells. The disease seems to be different from the retinopathy described in the English Briards. It is not clear yet whether the lipid type of retinopathy found in American Briards is identical to the present disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01203343
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    Electronic Resource
    Electronic Resource
    UV-B and early cortical and nuclear changes in the human lens (1994)
    Springer
    Documenta ophthalmologica 88 (1994), S. 255-261 
    Details
    ISSN: 1573-2622
    Keywords: UV-irradiation ; Human lens ; Ageing ; Defense mechanisms ; Biomicroscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Experimental studies in mice and rats have shown that UV (B) irradiation leads to specific lens changes, viz. yellowing of the nucleus and a multilayered epithelium in the anterior pole with disrupted cortical fibres underneath. Biomicroscopic and ultrastructural studies on ageing human lenses revealed yellowing of the lens nucleus and locally ruptured membranes and small opcities in the equatorial cortex. No changes in the anterior pole were ever observed. This discrepancy between the human and animal lens, contraindicating UV as an important risk factor for human cataract, is discussed and may be due to several factors: (1) a difference between the high level acute and low level chronic irradiation; (2) species differences: nocturnal animals may be unable to cope with bright light exposure; (3) differences in scavenger and other defense mechanisms between humans and animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01203679
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  • 49
    Electronic Resource
    Electronic Resource
    Effects of aflatoxin B1 on in vitro cultures ofNicotiana tabacum var. Samsun (1994)
    Springer
    Mycopathologia 125 (1994), S. 93-105 
    Details
    ISSN: 1573-0832
    Keywords: Aflatoxin B1 ; Callus ; Differentiation ; Electron microscopy ; Organogenesis ; Tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Calli ofNicotiana tabacum (tobacco) were treated with two dose ranges of aflatoxin B1 (0.1–2.0 µg ml−1 - low does; 5–25 µg ml−1 aflatoxin B1). The ability of calli to recover following 3 weeks of toxin exposure was also investigated. The I50 (50% inhibition) value for fresh mass accumulation was approximately 2 µg ml−1 AFB1. Fresh mass accumulation was significantly lower than the control value from 0.5 µg ml−1 AFB1. Following 3 weeks growth without a toxin source, the growth of calli up to and including 10 µg ml−1 AFB1, was significantly greater than control calli, indicating reversibility of the toxic effects. With increasing toxin concentration, chlorophyll content of callus was inhibited from 0.5 µg ml−1. Transfer to a toxin-free medium resulted in a degree of recovery (up to 0.5 µg ml−1). In the dose range 5–25 µg ml−1, the levels of chlorophyll were drastically reduced, with no recovery following AFB1 removal. Electron microscopy revealed a disruption of chloroplast structure as an early deteriorative event in AFB1 exposure of callus cells. Protein levels were less sensitive, with inhibition manifested only in the high dose range. Shoot development occurred at all concentrations, but was significantly inhibited from 5 µg ml−1 AFB1. Recovery following toxin removal was minimal at these higher AFB1 concentrations. The number of necrotic calli increased progressively from 5 µg ml−1 as toxin levels increased.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01371098
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  • 50
    Electronic Resource
    Electronic Resource
    Electron microscopic and light scattering observation on a system with two iridescent phases (1994)
    Springer
    Colloid & polymer science 272 (1994), S. 604-611 
    Details
    ISSN: 1435-1536
    Keywords: Electron microscopy ; light scattering ; dodecyldimethylaminoxide/hexanol/water ; iridescent phase ; bicontinuous sponge phase ; vesicle phase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Electron microscopic observations and classical light-scattering measurements have been carried out for dodecyldimethylaminoxide/hexanol/water mixtures in the concentration range where iridescent colors occur. This system has two different iridescent phases. The iridescent phase with more hexanol forms quickly, and the phase with less hexanol forms very slowly. Three different isotropic phases which show strong flow birefringence are found near both iridescent phases. The electron microscopic pictures show clearly that only one of these isotropic phases with strong flow birefringence is a bicontinuous sponge phase (L3h -phase). This is the phase which comes out by adding some alkanol to the upper lamellar phase. The flow birefringent phase below the lower lamellar phase forms unilamellar vesicles. The flow birefringent phase which occurs between both iridescent phases contains multilamellar vesicles and is shown to be a precursor of a lamellar phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00653228
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  • 51
    Electronic Resource
    Electronic Resource
    Ultrastructure of Reissner's membrane in the rabbit (1994)
    Springer
    European archives of oto-rhino-laryngology and head & neck 251 (1994), S. 249-256 
    Details
    ISSN: 1434-4726
    Keywords: Reissner's membrane ; Electron microscopy ; Tubulocisternal endoplasmic reticulum ; Subsurface cistern ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ultrastructure of Reissner's membrane in the rabbit is described following vascular perfusion-fixation of live, anesthetized and artificially respirated healthy animals. A new and improved technique of fixation is employed that includes a pressure feedback controlled peristaltic pump and an oxygen-carrying fixative. In ultrathin sections capillaries were observed between the two cell layers comprising Reissner's membrane. The mesothelial cells facing the scala vestibuli were connected by junctional complexes and neither pores nor discontinuities were observed in the cell layer. In the epithelial cells a well-developed tubulocisternal endoplasmic reticulum (TER) was noted. Computerized three-dimensional reconstruction documented the continuity of this TER, from prominent disc-shaped subsurface cisterns lining the luminal cell membrane to smaller subsurface cisterns lining the abluminal and lateral cell membranes, forming a transcellular canalicular pathway. The possible function of the TER in Reissner's membrane is discussed with reference to endolymph/perilymph homeostasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00181879
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  • 52
    Electronic Resource
    Electronic Resource
    Morphological changes in the tectorial and basilar membranes of aged rats (1994)
    Springer
    European archives of oto-rhino-laryngology and head & neck 251 (1994), S. 357-360 
    Details
    ISSN: 1434-4726
    Keywords: Presbycusis ; Extracelluar matrix ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using both light and transmission electron microscopy presbycusic degeneration of the cochlea was observed in particular in the tectorial and basilar membranes, in naturally aged rats. These animals showed a descending auditory pattern as determined by auditory brainstem response. Ultrastructurally, the number of collagen fibers in the tectorial membrane was reduced and straight type A fibers were increased relative to branched, coiled type B fibers. The basilar membrane in the basal turn was also thickened by an increased homogeneous ground substance. These findings indicate that the specificity of vibration of the tectorial and basal membranes is very different in aged and young rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00171545
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  • 53
    Electronic Resource
    Electronic Resource
    An ultrastructural study of nonfunctioning adrenocortical adenoma (1994)
    Springer
    Medical molecular morphology 27 (1994), S. 27-32 
    Details
    ISSN: 1860-1499
    Keywords: Nonfunctioning adrenocortical adenoma ; Ultrastructural study ; Electron microscopy ; Nonfunctioning adrenocortical black adenoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nonfunctioning adrenocortical adenomas obtained from 40 and 60-year-old males were examined by electron microscopy. Light microscopically, the tumors were shown to consist of clear cells and compact cells in both cases. However, compact cells predominated in the former case, and clear cells in the latter. Electron microscopy revealed that most of the cells in the former case had abundant organelles, including well-developed, smooth and rough endoplasmic reticulum, Golgi apparatus, and mitochondria with elaborate tubulovesicular cristae. The findings resembled those of adenomas with Cushing's syndrome. The latter case revealed a majority of cells with numerous, large lipid vacuoles, moderate amounts of smooth endoplasmic reticulum, Golgi apparatus, and mitochondria with sparse lamellar cristae resembling features of aldosteronoma. These ultrastructural findings suggest that even nonfunctioning adrenocortical adenomas, like functioning adrenocortical adenomas, have some possibility of producing adrenal hormones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02348223
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  • 54
    Electronic Resource
    Electronic Resource
    A case of endometrial stromal tumor with epithelial elements (1994)
    Springer
    Medical molecular morphology 27 (1994), S. 45-47 
    Details
    ISSN: 1860-1499
    Keywords: Endometrial stromal tumor ; Epithelial element ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A rare endometrial stromal tumor with marked epithelial differentiation was found in a 56-year-old female. This polypoid tumor, occupying the uterine cavity, was composed of an admixture of endometrial stromal and glandular components. Ultrastructurally and immunohistochemically, it is suggested that these epithelial elements were derived from epithelial differentiation of the endometrial stromal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02348227
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  • 55
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    Electronic Resource
    An ultrastructural study of primary granule subtypes in human neutrophils from chronic myeloproliferative disorders (1994)
    Springer
    Medical molecular morphology 27 (1994), S. 99-112 
    Details
    ISSN: 1860-1499
    Keywords: Primary granule subtype ; Chronic neutrophilic leukemia ; Chronle myeloproliferative disorder ; Human neutrophil ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The bone marrow of 17 patients with chronic myeloproliferative disorders (CMPDs) was investigated by electron microscopy. Three subtypes of primary granules, i.e., parallel tubular granules (PTGs), fibrillar granules (FGs), and periodic lamellar granules (PLGs), were found in neutrophils from the CMPDs. Only one case of chronic neutrophilic leukemia (CNL) showed PTGs. Both FGs and PLGs were found in various CMPDs in varying frequencies. These granules tested positive for myeloperoxidase, and were seen primarily in immature neutrophils. In addition, the presence of hybrid FG/PTG granules and hybrid FG/PLG granules was confirmed. These results suggest that PTGs, FGs, and PLGs represent subtypes of primary granules, and that a close association exists between them.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02348175
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  • 56
    Electronic Resource
    Electronic Resource
    The correlation between muscle magnetic resonance images and histopathological findings in a patient with myotonic dystrophy (1994)
    Springer
    Medical molecular morphology 27 (1994), S. 145-148 
    Details
    ISSN: 1860-1499
    Keywords: Myotonie dystrophy ; MRI ; Histopathology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined the correlation between magnetic resonance images (MRI) and histopathological findings in a patient with myotonic dystrophy. Tl-weighted images showed more severe abnormalities in the distal muscles than in the proximal muscles in the lower extremity. Histopathological examination showed the progression of muscle disorganization, degeneration, necrosis and atrophy in areas in which the distribution of high intensity signals was increased on Tl-weighted images. Our findings suggest that histopathological changes in the muscles of patients with myotonic dystrophy can be evaluated using Tl-weighted images.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02348179
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  • 57
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    Electronic Resource
    An ultrastructural study on anterior cruciate ligament reconstruction using autogenous patellar tendon grafts in dogs (1994)
    Springer
    Medical molecular morphology 27 (1994), S. 149-158 
    Details
    ISSN: 1860-1499
    Keywords: Anterior eruciate ligament reconstruction ; Collagen fibril ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An ultrastructural study was undertaken concerning morphological changes within the autografted patellar tendon (PT) after being transplanted to the anterior cruciate ligament (ACL) in mongrel dogs. After 4 weeks, the arrangements of both large and small collagen fibrils in the PT graft became disordered, and the number of inflammatory cells increased. However, the same PT grafts revealed postsurgical signs of newly-produced collagen fibrils around activated fibroblasts at 12 to 24 weeks. At 52 weeks after the transplantation, small collagen fibrils increased in both number and density, showing a remarkable morphological similarity to the collagen fibrils of normal ACL. These data indicate that the characteristics of the PT graft eventually resemble those of a normal ACL.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02348180
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  • 58
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    Electronic Resource
    Immunohistochemistry of proliferating cell nuclear antigen (PCNA), laminin, and electron microscopy by tannic acid fixation in surface epithelial-stromal ovarian tumors (1994)
    Springer
    Medical molecular morphology 27 (1994), S. 268-270 
    Details
    ISSN: 1860-1499
    Keywords: PCNA ; Laminin ; Tannic acid ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The distribution of proliferating cell nuclear antigen (PCNA), laminin, and basement membrane in surface epithelial-stromal ovarian tumors was studied using immunohistochemical and cytochemical techniques. PCNA is a useful means of differentiating between borderline and malignant tumors. The distribution of laminin-positive materials in malignant tumors showed that laminin synthesis in these tumors is quite different from that which occurs in benign or borderline tumors. This corresponded with electron microscopic findings by tannic acid fixation showing pleomorphism of cell organelles and discontinuity of the basement membrane in malignant tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02349672
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  • 59
    Electronic Resource
    Electronic Resource
    Standard methods of electron microscopic radioautography (1994)
    Springer
    Medical molecular morphology 27 (1994), S. 347-351 
    Details
    ISSN: 1860-1499
    Keywords: Radioautography ; Image analysis ; Electron microscopy ; Quantitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The standard methods of making electron microscopic radioautograms and quantitation of silver grains in our laboratory were presented. Specialized techniques for insoluble or soluble compounds should be employed for demonstrating the synthesis of various macromolecules and the incorporation of various labeled substances. Specimens for electron microscopic radioautography processed under the same conditions can be employed for the quantitation of radioactive substances in subcellular compartments using image analyzers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02349693
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  • 60
    Electronic Resource
    Electronic Resource
    Use of analytical electron microscopy in clinical medicine (1994)
    Springer
    Medical molecular morphology 27 (1994), S. 343-345 
    Details
    ISSN: 1860-1499
    Keywords: Energy dispersive X-ray microanalysis ; Electron microscopy ; Silicone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Granuloma after liquid silicone augmentation of the eyelids was studied by light and electron microscopy and energy dispersive X-ray microanalysis. Light and electron microscopy showed many vacuoles in phagocytic macrophages. Vacuoles in phagocytic macrophages and granules in extracellular spaces contained silicone which was demonstrated by energy dispersive X-ray microanalysis (EDXA). The present study showed the possibility to prove silicone in the usual histological and electron microscopic procedures with EDXA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02349692
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  • 61
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    Electronic Resource
    Perspective on hepatic peroxisomes and pancreatic hepatocytes (1994)
    Springer
    Medical molecular morphology 27 (1994), S. 181-190 
    Details
    ISSN: 1860-1499
    Keywords: Peroxisomes ; Peroxisome proliferator ; Pancreatic hepatocytes ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Continued exposure to certain hypolipidemic drugs, plasticizers and herbicides leads to proliferation of peroxisomes in hepatic parenchymal cells. Sustained induction of peroxisome proliferation leads to the development of liver tumors in rats and mice. Peroxisome proliferator-induced pleiotropic responses, including the development of phenotypic properties in liver tumors induced by these agents, have been examined using autoradiography, immunofluorescence, immunoperoxidase, immunoelectron microscopy andin situ hybridization procedures in conjunction with northern blot and immunoblotting procedures. These studies confirmed that the biological effects of peroxisome proliferators were confined predominantly to liver cells and that the tumors appeared only in this organ. The cell specific effects of peroxisome proliferators have been documented in studies on the induction of peroxisome proliferationin vitro in primary liver cell cultures, in hepatocytes transplanted in subcutaneous fat or the anterior chamber of the eye in rats, and in rats with transdifferentiated pancreatic hepatocytes of the copper-deficiency model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02349657
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  • 62
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    Electronic Resource
    Localization of neurofilament protein mRNA in rat trigeminal ganglion byin situ hybridization at light and electron microscopic levels (1994)
    Springer
    Medical molecular morphology 27 (1994), S. 373-374 
    Details
    ISSN: 1860-1499
    Keywords: Radioautography ; In situ hybridization ; Neurofilament protein ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract By use ofin situ hybridization with a35S-labeled oligonucleotide probe, the mRNA for neurofilament protein was localized to the trigeminal ganglion cells of rats. The result was visualized with radioautography at both light and electron microscopic levels. For the latter purpose, the cryostat sections were treated forin situ hybridization prior to embedding in epoxy resin. The presence or absence of detergent in the hybridization solution proved to be critical for the electron-microscopicin situ hybridization in terms of the signal/background ratio and ultrastructural integrity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02349701
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  • 63
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    Electronic Resource
    Masthead (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994) 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100101
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  • 64
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    Electronic Resource
    Iterative computation of second-order derivatives of eigenvalues and eigenvectors (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 1-9 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An iterative method is introduced for computing second-order partial derivatives (sensitivities) of eigenvalues and eigenvectors of matrices which depend on a number of real design parameters. Numerical tests confirm the viability of the method and support our theoretical analysis. Alternative methods are reviewed briefly and compared with the one proposed here.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100102
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  • 65
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    Electronic Resource
    Semi-Loof element for plate instability (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 11-19 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In the formulation of the semi-Loof element the rotation of the tangent plane is derived from the interpolation of the transverse displacement, while the rotation of the normal is interpolated separately by another set of shape functions. The geometric stiffness matrix can be formulated by use of either of the two rotation representations. It is demonstrated that the use of the tangent plane representation in the geometric stiffness matrix is far superior to the common form at present.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100103
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  • 66
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    Least-squares T-elments: Equivalent FE and BE forms of a substructure-oriented boundary solution approach (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 21-32 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An efficient solution to boundary-value problems may be based on the application of a suitably truncated T-complete set of Trefftz functions over individual subdomains and on linking the fields by a least-squares procedure. Although it yields a symmetric system of linear equations, this approach as originally presented by Zielinski and Zienkiewicz is not suited for implementation into FE codes. The present paper presents two equivalent formulations, which take respectively the form of the finite (FE) and non-conventional boundary-element (BE) approach. Both allow the resulting simultaneous equations to be assembled following the standard direct stiffness methods and can readily be implemented into existing FE codes.As in the conventional p-method, the accuracy may be controlled within large limits without increasing the number of elements. The present approach allows substantial saving in computer time in comparison with the so-called hybrid-Trefftz (HT) elements, though the assumed displacement fields are identical. The practical efficiency of the new T-element approach is assessed on the problem of stress concentration in a symmetrically compressed perforated panel.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100104
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  • 67
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    High-order polynomial interpolation in boundary integral equation analysis (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 167-178 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A sixth-order polynomial shape function is developed for BIE analysis. The function is applied over only three-noded elements, but with the support for the function extending over adjacent elements. This avoids the oscillations near the ends of the range which otherwise are characteristic of high-order polynomial interpolation. Various test problems are explored, and it is shown that results as accurate as those from conventional quadratic elements are obtained with larger nodal spacings, and thus giving the potential for significant reductions in matrix storage requirements and solution times.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100208
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  • 68
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    Accurate finite element method for steady and quasisteady lifting aerofoil (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 155-166 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A finite element formulation based on superposition is proposed for a lifting aerofoil in incompressible potential flow. An accuracy improvement technique for the singularity at the aerofoil trailing edge is discussed. It is shown that the quarter-node quadrilateral element can be readily employed to simulate this singularity. It is also demonstrated that the circulation in the flow field can be easily represented by a single constraint equation rather than introducing an artificial cut line in the mesh. The influence of finite-element mesh size on solution accuracy and the correct form of the boundary condition have been investigated as well. Numerical examples are given for both steady and quasisteady Joukowski aerofoils of various thicknesses and at a range of incidences. In all test cases, good agreement is observed between the analytical solution and the numerical result.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100207
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  • 69
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    Masthead (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994) 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100301
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  • 70
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    A 3D element for non-linear analysis of solids (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 183-194 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An 8-node element (HMITC) for 3D non-linear analysis of solids is presented. The new element is based on an element developed by Wilson and Ibrahimbegovic, that incorporates incompatible modes, and on the method of mixed interpolation of tonsorial components. The HMITC element does not contain spurious zero energy modes and satisfies Irons' Patch Test. The numerical experimentation indicates that the HMITC has good performance even with distorted meshes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100302
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  • 71
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    Space-time oriented streamline diffusion methods for non-linear conservation laws in one dimension (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 203-215 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In this paper we consider an explicit finite-element method, with elements adaptively oriented in space-time, for the solution of one-dimensional conservation laws, extending previous work dealing with linear convection-diffusion and incompressible flow. In particular we consider Burgers' equation and the compressible Euler equations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100304
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    Neural-network-based approximations for solving partial differential equations (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 195-201 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A numerical method, based on neural-network-based functions, for solving partial differential equations is reported in the paper. Using a ‘universal approximator’ based on a neural network and point collocation, the numerical problem of solving the partial differential equation is transformed to an unconstrained minimization problem. The method is extremely easy to implement and is suitable for obtaining an approximate solution in a short period of time. The technique is illustrated with the aid of two numerical examples.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100303
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    Cyclic symmetry in boundary elements (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 217-225 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An efficient algorithm for consideration of axial and cyclic symmetry in the boundary-element method is presented. The appropriate transformation relationships was derived. The algorithm is then implemented in a boundary element program for the analysis of 2D elastostatic problems. Through analysis of typical problems the validity of the algorithm and its implementation is verified. A high level of accuracy and substantial reduction in computer time and storage was achieved.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100305
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    Explicit variable time-step method for implicit moving boundary problems (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 227-235 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The diffusion of oxygen into an absorbing medium as an example of an implicit moving boundary problem has been dealt with by a number of authors using various numerical techniques, and, where appropriate, approximate analytical expressions. To evaluate the time for complete absorption, extrapolation is usually employed. An unconditionally stable explicit numerical scheme that avoids the limitations of such methods is presented and tested herein. Unlike existing schemes this method is fully numerical; it avoids the large array size, generally required for existing methods, by using a variable-length time step. The time for complete absorption emerges from the final step in the normal computing procedure with no recourse to extrapolation. Furthermore, owing to the implicit condition prevailing at the moving boundary, no iterations are needed to evaluate the time step required for the moving boundary to move a single space increment. The numerical results obtained compare very favourably with those due to earlier authors.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100306
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    Boundary-element solution of some structural-acoustic coupling problems using the multiple reciprocity method (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 237-248 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In the paper we have developed a new formulation for solution of structural-acoustic coupling problems by boundary elements using the multiple reciprocity method. It is assumed that the structure is composed of plate components and is excited by the external or the internal noise source. The efficiency of the proposed formulation becomes especially remarkable if the boundary-value problem is to be solved repeatedly for different values of frequency. The accuracy of the numerical computations has been compared with the analytical solution in a test example.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100307
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    Homogenization and effective elastoplasticity models for periodic composites (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 257-265 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Techniques for stress- and strain-controlled in situ homogenization of inelastic periodic composites are presented. The results of homogenization computations on a specific elastoplastic composite solid are then employed to validate the form of an orthotropic elastoplasticity model with a tensorial kinematic hardening law.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100309
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  • 77
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    Lagrange multiplier approach for evaluation of friction in explicit finite-element analysis (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 249-255 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An algorithm for evaluation of friction in general contact-impact interfaces is described. The algorithm is based on an explicit finite-element method. Coulomb's friction law is assumed. The defence node algorithm is used such that the sticking condition can be imposed with the Lagrange multiplier method even in explicit dynamic analysis. The algorithm is supposed to be applicable in general situations, including large deformations of the contact-impact bodies and large relative sliding between the contact-impact boundaries. Numerical results are presented to demonstrate the performance of the algorithm.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100308
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  • 78
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    Conference diary (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 275-277 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100311
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    Masthead (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994) 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100401
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  • 80
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    General forming of transition elements (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 267-273 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A generalization of the r(1-m)/m strain singularity of higher-order isoparametric elements is presented. It is shown that, by variable placement of the side nodes between their original and singular positions, the point of singularity sensed by the element can be controlled. The transition elements have a strain singularity outside their domain. The singular and non-singular elements are elements are special cases of the general mapping. The transition elements, together with the singular isoparametric elements, can be used for solving crack problems.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100310
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  • 81
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    Some geometric problems related to fracture-control in complex structures (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 279-290 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In the design of members with flaws, it is necessary to keep the stress intensity factor K of any sharp crack below the fracture toughness Kcr of the materials. Stress-intensity factor equations for the more common basic specimen geometries and various loading conditions are available in the literature. The application of these equations to complex structures involves geometric problems such as the identification of the outline of each member and the sizing of the equivalent specimen for each flaw. The paper gives a response to such difficulties.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100402
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  • 82
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    Modified simplex optimization program (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 303-312 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A simple, yet storage-effective ‘linear’ programming code is given. The assumption of non-negative variables is bypassed without increasing the size of the problem. Furthermore, the objective is allowed to be summed over not just linear, but also concave, functions. A specific truss topology optimization example is shown.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100405
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    Fourth-order difference method for quasilinear Poisson equation in cylindrical symmetry (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 291-296 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: We propose in this paper a nine-point, fourth-order difference method for the numerical solution of the quasilinear Poisson equation \documentclass{article}\pagestyle{empty}\begin{document}$$ Au_{zz} + \frac{1}{r}u_r + Bu_{rr} = f\left({r,z,u,u_r,u_z} \right) $$\end{document} with appropriate boundary conditions. The method is based on five evaluations of f. The numerical results of four problems obtained using this method are listed. The results demonstrate the fourth-order accuracy of the method.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/cnm.1640100403
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    Use of central-difference operators for solution of singularly perturbed problems (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 297-302 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Singularly perturbed second-order elliptic equations with boundary layers are considered. These may be considered as model problems for the advection of some quantity such as heat or a pollutant in a flow field or as linear approximations to the Navier-Stokes equations for fluid flow. Numerical methods composed of central-difference operators on special piece-wise-uniform meshes are constructed for the above problems. Numerical results are obtained which show that these methods give approximate solutions with error estimates that are independent of the singular perturbation parameter. An open theoretical problem is posed.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100404
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    Superconvergent patch recovery of finite-element solution and a posteriori L2 norm error estimate (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 313-320 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In the paper we present a superconvergent patch recovery technique for obtaining higher-order-accurate finite-element solutions and thus a postprocessed type of L2 norm error estimate. Two modifications make our procedure different from the one proposed by Zienkiewicz and Zhu (1992), in which higher-order-accurate derivatives of the finite-element solution at nodes are determined. Firstly, the recovery process is made for element, not for nodes. An ‘element patch’, which represents the union of an element under consideration and the surrounding elements, is introduced. Secondly, the local error estimate is calculated directly from the improved solution for this element. Numerical tests on both 1D and 2D model problems show that this method can provide an asymptotically exact a posteriori L2 norm error estimate if the used element possesses superconvergent points for the solutions.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100406
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    Universal matrices with new infinite elements for quasiharmonic equation (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 321-331 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A new approach to developing serendipity quadrilateral infinite elements is presented. Using these elements universal matrices for quasiharmonic equation are developed. For a particular member of the family these matrices are independent of the size and shape of the element. Using these matrices the element stiffness matrix can be generated in a simpler manner by taking into account the size and shape of the element.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cnm.1640100407
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    Accelerated modified Newton-Raphson iteration-based finite-element solution of structural problems involving non-linear deformation behaviour (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 333-338 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A new global secant relaxation (GSR)-method-based improvement procedure is used to improve the overall convergency performance of the modified Newton-Raphson iteration in carrying out the solution of discrete systems resulting from the finite-element discretization of a certain class of structural problems involving non-linear deformation behaviour.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100408
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    A simulation of free-surface electrohydrodynamic flow (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 339-353 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Theoretical and experimental analysis of free-surface electrohydrodynamic flow is fragmented and incomplete. Simulation studies of this phenomenon are further limited by the inherent complexities in the modelling process. In this note a mathematical model is developed to analyse free-surface electrohydrodynamic flow in two dimensions, and preliminary results of the simulation are described. The configurations examined include electrified conducting surfaces, the dielectrophoretic forces, and a conducting jet. The simulation is compared with analytical results in the first two investigations and is shown to be quite accurate. In the last simulation it is demonstrated that in the initial formation of a conducting jet, a 10 per cent increase in applied voltage results in about a 10 per cent increase in fluid velocity.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100409
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  • 89
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    Conference diary (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 355-357 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100410
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    Announcements (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 359-360 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100411
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    Masthead (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994) 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100501
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  • 92
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    Improvement on dual reciprocity boundary element method for equations with convective terms (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 361-371 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The dual reciprocity boundary element method, first proposed by Nardini and Brebbia (1982, 1985), is a powerful technique for solving elliptic partial differential equations. Adopting this approach, a singular volume integral, which needs to be evaluated with a traditional boundary element method, can be converted into a boundary integral. However, when the governing equation is of a certain type, this conversion fails due to the singularities being introduced inside the physical domain and on the boundary arising by differentiating distance functions. We avoid these artificially created singularities by constructing a transformation which leads to improved numerical results.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100502
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    A direct solver for the least-squares problem arising from GMRES(k) (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 743-749 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This is a study about one of the core questions in the GMRES(k) method regarding the obtaining of vector yk for the least-squares problem, argminy |Hky - β(n)e1|2 (see Saad and Schultz1). We propose a simple but efficient approach to the resolution of this problem and a low cost computation of the residual and the residual norm, including both in a complete and detailed FGMRES(k) algorithm. The whole algorithm of minimization only involves two backward substitutions with triangular matrices and a dot product. The residual and the residual norm are computed, making use of results in the least-squares problem.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100909
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    Conference diary (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 759-760 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100911
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    Announcements (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 761-762 
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    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100912
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    Masthead (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994) 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640101001
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    An algorithm for the optimization of directionally stretched triangulations (1994)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 37 (1994), S. 1481-1497 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A procedure for the optimization of stretched triangular grids is described. The method is based on the construction and minimization of a function that represents a generalized version for stretched grids of a non-linear spring system. The function is minimized using a gradient method based on the steepest descent. Examples are provided to show the applicability of the method to computational fluid dynamics problems.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620370905
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    Optimum application of the multigrid method in generating body-fitted co-ordinates (1994)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 37 (1994), S. 1465-1480 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Multigrid method is used to accelerate the convergence of the numerical solution of the set of partial differential equations for generating the Body-Fitted Co-ordinate system (BFC) for both simply and doubly connected domain problems. The multigrid method is based on the full approximation scheme with bilinear interpolation as prolongation operator. The other components of the multigrid method such as the relaxation method, restriction operator, number of relaxation sweeps per cycle and direction of relaxation sweeps are varied with a view to obtaining the general principle in implementing an efficient multigrid algorithm for the generation of the BFCs.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620370904
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    Node and element resequencing using the Laplacian of a finite element graph: Part II - Implementation and numerical results (1994)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 37 (1994), S. 1531-1555 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In Part I of this work, Paulino et al.1 have presented an algorithm for profile and wavefront reduction of large sparse matrices of symmetric configuration. This algorithm is based on spectral properties of a Finite Element Graph (FEG), An FEG has been defined as a nodal graph G, a dual graph G* or a communication graph G· associated with a generic finite element mesh. The novel algorithm has been called Spectral FEG Resequencing (SFR). This algorithm has specific features that distinguish it from previous algorithms. These features include (1) use of global information in the graph, (2) no need of a pseudoperipheral vertex or the endpoints of a pseudodiameter, and (3) no need of any type of level structure of the FEG. To validate this algorithm in a numerical sense, extensive computational testing on a variety of problems is presented here. This includes algorithmic performance evaluation using a library of benchmark test problems which contains both connected and non-connected graphs, study of the algebraic connectivity (λ2) of an FEG, eigensolver convergence verification, running time performance evaluation and assessment of the algorithm on a set of practical finite element examples. It is shown that the SFR algorithm is effective in reordering nodes and/or elements of generic finite element meshes. Moreover, it computes orderings which compare favourably with the ones obtained by some previous algorithms that have been published in the technical literature.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620370908
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    The benefits of parallel multibody simulation (1994)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 37 (1994), S. 1557-1572 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: To exploit the benefits of parallel computer architectures for multibody system simulation, an interdisciplinary approach has been pursued, combining knowledge of the three disciplines of dynamics, numerical mathematics and computer science. An analysis of the options available for the formulation and numerical solution of the dynamical system equations yielded a surprising result. A method initially proposed to solve the inverse problem of dynamics is the best choice to generate the system equations required for solving the simulation problem, when relying on implicit integration routines. Such routines have the particular advantage of handling stiff systems, too. The new O(N)-residual formalism, generating the system equations in a form required for implicit numerical integration, has a high potential to benefit from parallel computer architectures. Two strategies of medium and coarse grain parallelization have been implemented on a Transputer network to obtain a package for parallel multibody simulation. An analysis of the performance of this package demonstrates for typical multibody simulation problems that the new code is five times faster than existing codes when implemented on a serial computer. An additional speed-up by the same order of magnitude is obtained when the code is implemented on a Transputer network.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620370909
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