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  • Articles: DFG German National Licenses  (291)
  • 1995-1999
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  • Articles: DFG German National Licenses  (291)
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  • 1995-1999
  • 1990-1994  (57)
  • 1975-1979  (234)
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  • 1
    Electronic Resource
    Electronic Resource
    Diethylene glycol (DEG)-associated myocardial changes: A pilot investigation of chronic intoxication in guinea-pigs (1991)
    Springer
    International journal of legal medicine 104 (1991), S. 93-97 
    Details
    ISSN: 1437-1596
    Keywords: Diethylene glycol ; Intoxication ; Myocardium ; Myocytolysis ; Ultrastructure ; Mitochondria ; Guinea pig ; Diethylenglycol ; Intoxikation ; Myokard ; Myozytolyse ; Ultrastruktur ; Mitochondrien ; Meerschweinchen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung Das Myokard von Meerschweinchen, welche mit subletalen Mengen von Diethylenglycol über eine Zeitdauer von 2–11 Tagen gefüttert worden waren, wurde mikroskopisch und elektronenmikroskopisch untersucht. Eine Koagulationsmyozytolyse und Verlust von Myofibrillen war fleckförmig verstreut über das Myokard. Diese Veränderungen waren in den Kontrollen nicht zu beobachten. Die begleitenden ultrastrukturellen Veränderungen bestanden in Schwellung, Pleomorphie, Hyperplasie von Mitochondrien, begleitet von einer Erweiterung der interfibrillären Räume und Verlagerung, Verzerrung und Ruptur angrenzender Fibrillen.
    Notes: Summary The myocardium of guinea pigs fed on sublethal doses of diethylene glycol (DEG) over a period of 2–11 days was examined for microscopical and ultrastructural changes. Coagulative myocytolysis and loss of myofibrils, not observed in the controls, was patchily distributed throughout the myocardium. The accompanying ultrastructural features included swelling, pleomorphism and hyperplasia of mitochondria with an associated distension of the interfibrillary spaces and a displacement, distortion and rupture of adjacent myofibrils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01626038
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of dopamine agonist medication on prolactin producing pituitary adenomas (1991)
    Springer
    Virchows Archiv 418 (1991), S. 439-446 
    Details
    ISSN: 1432-2307
    Keywords: Bromocriptine ; Pituitary neoplasm ; Prolactin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Conventional light microscopy, immunocyto-chemistry, electron microscopy and in situ hybridization were used to evaluate the effect of dopamine agonists (bromocriptine-LAR and bromocriptine) on the morphology of surgically removed prolactin (PRL)-producing pituitary adenomas. Dopamine agonist therapy resulted in decrease of serum PRL, clinical improvement and tumour shrinkage. Using light and electron microscopy cellular atrophy, interstitial and perivascular fibrosis were noted; in several tumours connective tissue accumulation was pronounced. The cellular response was not uniform. In some adenomas populations of large cells and small cells were distinguished. The large cells contained immunoreactive PRL and expressed the PRL gene indicating resistance to dopamine agonists. It appears that these cells retained the potential to secrete PRL and proliferate despite exposure to dopamine agonists. In the small cells, PRL immunoreactivity and PRL gene expression decreased providing evidence that both PRL release and synthesis were blocked. Small cells can persist in tumours after discontinuation of dopamine agonist medication suggesting these small cells are irreversibly suppressed and are not capable of regaining their endocrine function and proliferative capability. The formation of irreversibly suppressed PRL cells may explain why some PRL-producing adenomas do not recur after withdrawal of dopamine agonists.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01605931
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  • 3
    Electronic Resource
    Electronic Resource
    Immunohistochemical characterization of HLA-DR-antigen positive dendritic cells in phaeochromocytomas and paragangliomas as a prognostic marker (1991)
    Springer
    Virchows Archiv 418 (1991), S. 33-39 
    Details
    ISSN: 1432-2307
    Keywords: HLA-DR ; Phaeochromocytomas ; Paragangliomas ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Twelve cases of phaeochromocytoma (PCC) and four cases of paraganglioma (PGG) were studied by immunohistochemistry and immunoelectron microscopy in order to demonstrate HLA-DR (Ia)-antigen-positive dendritic cells (IaDCs). Dense infiltration of IaDCs was detected in the majority of PCCs revealing high urinary or serum catecholamine levels, but in aggressively growing PCCs, a familial PCC and all PGGs, few IaDCs were demonstrated. Interestingly, these IaDCs were negative for S-100 protein. Although S-100-protein-positive sustentacular-like cells (SCs), morphologically similar to IaDCs, were also present, these were clearly distinguished from IaDCs by our double immunostaining method. Ultrastructurally, IaDCs had smooth or slightly indented nuclei and contained a moderate amount of endoplasmic reticulum, small mitochondria and vacuoles, extending elongated cytoplasmic processes. These results suggest that determination of the quantity of IaDCs is a highly effective method of assessing the character of PCCs, in particular, their prognosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600242
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  • 4
    Electronic Resource
    Electronic Resource
    Cell-mediated cytotoxicity in acute rat cardiac allograft rejection: An immunological and ultrastructural study (1991)
    Springer
    Virchows Archiv 418 (1991), S. 41-50 
    Details
    ISSN: 1432-2307
    Keywords: Cell-mediated cardiocyte injury ; Acute cardiac allograft rejection ; Mononuclear cellular infiltration ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To clarify the immune mechanism of cytotoxicity in acute cardiac allograft rejection, we observed interactions between cardiocytes and mononuclear cells using immunohistochemistry and light and electron microscopy. All allografted WKA rat hearts transplanted to F344 recipients stopped beating by the 7th day after the transplantation. The population of helper/inducer T cells (Th) and IL2R+ cells was large for the first 3 days, whereas that of cytotoxic/suppressor T cells (Tc-s) and macrophages increased from the 4th day. TheTh/Tc-s ratios were more than 2.0 until the 3rd day, then decreased to less than 1.0. In circulating T lymphocytes; theTh/Tc-s ratios were under 1.0 on the 1st, 6th and 7th days. Electron microscopically IL2R+ cells, Tc-s and macrophages were often seen in close contact with the plasma membrane of the cardiocytes. The majority of IL2R+ cells are NK cells, Tc-s andTh. Of these, the population of Tc-s was small until the 3rd day. Thus, NK cells play a pivotal role in the early stage of the rejection, and Tc-s and macrophages then aggravate cell-mediated cardiocyte injury.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600243
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  • 5
    Electronic Resource
    Electronic Resource
    Ultrastructure of oesophageal melanocytosis (1991)
    Springer
    Virchows Archiv 418 (1991), S. 515-522 
    Details
    ISSN: 1432-2307
    Keywords: Oesophagus ; Melanocyte ; Melanoma ; Ultrastructure ; Endoscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Four examples of an endoscopically detected oesophageal melanotic lesion were examined by light microscopy, light microscope histochemistry and transmission electron microscopy, and were compared with 13 control samples of normal oesophageal epithelium. By light microscopy, pigmented melanocytes lacking atypia and mitoses were observed amongst the keratinocytes in the basal layer of the oesophageal mucosa. Junctional activity was absent. The mechanism of pigmentation was studied and found to consist of: an increase in the number of melanocytes in the basal layer of the mucosa, an increase in the quantity of melanin in these melanocytes, transfer of melanin from melanocytes to keratinocytes and to macrophages and fibroblasts in the tunica propria. Since all the lesions demonstrated increased numbers of both melanocytes and melanosomes, the term oesophagealmelanocytosis rather thanmelanosis is suggested, to emphasise the essential character of the lesion as a cellular proliferation. The value of sampling these pigmented lesions during endoscopy is emphasised as a means of obtaining well-preserved material for the evaluation of a lesion which some authorities have viewed as a possible precursor for oesophageal malignant melanoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606502
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrastructural abnormalities of mitochondria and deficiency of myocardial cytochromec oxidase in a patient with ventricular tachycardia (1991)
    Springer
    Virchows Archiv 419 (1991), S. 63-68 
    Details
    ISSN: 1432-2307
    Keywords: Mitochondrial cardiomyopathy ; Ultrastructure ; Cytochromec oxidase deficiency ; Ventricular tachycardia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 30-year-old woman presented with lifethreatening ventricular tachycardia without overt heart disease. Ultrastructural investigation of endomyocardial biopsy disclosed abnormally structured and often enlarged mitochondria. Morphometry revealed the ratio of volume density of mitochondria to myofibrils to be markedly increased to 0.667 as compared with five controls (mean: 0.46; range: 0.445–0.479). Investigation of mitochondrial respiratory chain enzymes revealed a 90% reduction in activity of cytochromec oxidase. Our data suggest that mitochondrial cardiomyopathy may induce malignant ventricular arrhythmias.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600154
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  • 7
    Electronic Resource
    Electronic Resource
    Varicocele in the rat: a new experimental model (1991)
    Springer
    Urological research 19 (1991), S. 319-322 
    Details
    ISSN: 1434-0879
    Keywords: Varicocele ; Rat, Histology ; Ultrastructure ; Temperature ; Infertility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary With no consistent animal prototype for the study of varicocele, we set out to create a model in the rat by complete ligation of the main branch of left spermatic vein (MBSV) or by partial ligation of the left renal vein. Three months later, the histology, ultrastructure and temperature of the testis and epididymis were studied. Microscopically, spermatogenic arrest was the most frequent anomaly seen. The most frequently noted ultrastructural change of the testis was distension of smooth endoplasmic reticula in Sertoli cells. The microvilli of columnar epithelia in epididymis were sparse and showed local defects. Lesions and increased temperatures in the testis and epididymis induced by the ligation of the left MBSV were similar to those seen in partial ligation of the left renal veins, with no significant differences between left and right. Significant differences were found, however, on comparison with the controls.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00299069
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  • 8
    Electronic Resource
    Electronic Resource
    Morphology of the synovium during its differentiation and development in the mouse knee joint (1991)
    Springer
    Anatomy and embryology 183 (1991), S. 537-544 
    Details
    ISSN: 1432-0568
    Keywords: Synovial membrane ; Development ; Ultrastructure ; Scanning electron microscopy ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The prenatal and postnatal development of the mouse knee joint was investigated by transmission and scanning electron microscopy. In the prenatal stage, following the appearance of a narrow intercellular cleft between two skeletal elements on the 16th fetal day, clefting extended into the lateral synovial mesenchyme. In some regions, the extension of the cleft was very rapid, but in a certain region (future fat pad region), it was somewhat slower. Macrophage-like cells appeared in the synovial mesenchyme on the 16th fetal day, and then increased in number, and were distributed as if they were clustering around the presumptive clefting zone in the future fat pad region on the 17th–18th fetal day. This suggests that macrophage-like cells may participate in joint development, as they phagocytize and remove some kinds of solid extracellular matrix, and facilitate the cleft extension. In the early postnatal stage, scanning electron microscopic observations showed that there were two different types of cell in the synovial lining. One of them exhibited a surface morphology corresponding to that of macrophages: a spherical cell body and numerous pseudopodia. The other type of cell exhibited various cell shapes with many cytoplasmic processes extending along the synovial surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00187902
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  • 9
    Electronic Resource
    Electronic Resource
    Endothelial heterogeneity in the chick wing bud: A morphometric study (1991)
    Springer
    Anatomy and embryology 184 (1991), S. 47-53 
    Details
    ISSN: 1432-0568
    Keywords: Wing bud ; Endothelial cell ; Development ; Ultrastructure ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The microvascular endothelium of the chick wing bud at stages 22, 27, and 32 was evaluated by ultrastructural morphometry. The rationale for this study is based on the hypothesis that endothelial cells exhibit variation in structure and function during cytodifferentiation. The microvessels had a luminal diameter range such that they were classified as capillaries. The thin continuous endothelium was devoid of a basal lamina. The endothelium had a very small number of plasmalemmal vesicles; vacuoles were however present for all stages and in some cases were abundant. The temporal findings were that endothelial cell thickness increases, plasmalemmal vesicle densities decrease, and the densities of cytoplasmic vacuoles increase. The spatial results were that endothelial cells in proximal regions of the limb have a greater thickness, contain fewer vesicles and have more vacuoles than those in distal regions. In general, these results indicate that endothelial ultrastructural heterogeneity occurs within a 31/2 day timespan of wing bud development. The discussion considers the results with regard to recent reports on endothelial cell heterogeneity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01744260
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  • 10
    Electronic Resource
    Electronic Resource
    Development of taste organs inRana temporaria (1991)
    Springer
    Anatomy and embryology 184 (1991), S. 363-369 
    Details
    ISSN: 1432-0568
    Keywords: Taste organs ; Amphibia ; Development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In tadpoles ofRana temporaria two successive generations of taste organs: taste buds (TBs) and taste disks were studied. The TBs are located in the apices of oral premetamorphic papillae. Each TB consists of vertically elongated receptor cells (probably taste) and supporting cells. No basal (Merkel) cells were observed there. Morphologically, two types of receptor cells have been distinguished in a TB. Complete synaptic structures were observed in the TBs between the 30th and 41st of Gosner's (1960) developmental stages, though synaptic vesicles occur already at stage 26. The taste disks consist of taste cells, supporting cells and basal cells. Dense-core synaptic vesicles occur in the gustatory cells at stage 41, but complete synaptic structures were not observed earlier than at stage 45. Synaptic junctions observed at some of the gustatory cells seem to be reciprocal (bidirectional).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00957898
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  • 11
    Electronic Resource
    Electronic Resource
    The anatomy and fine structure of the echidnaTachyglossus aculeatus snout with respect to its different trigeminal sensory receptors including the electroreceptors (1991)
    Springer
    Anatomy and embryology 184 (1991), S. 371-393 
    Details
    ISSN: 1432-0568
    Keywords: Tachyglossus aculeatus (echidna) ; Echidna bill ; Sensory receptors ; Electroreceptor ; Mechanoreceptor ; Trigeminal nerve ; Monotreme ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The gross anatomy and nerve supply of the bill of echidna (Tachyglossus aculeatus) is described in relation to its function as an outstanding sensory organ. The sensory innervation of the skin of the echidna snout was investigated by means of frontal serial sections, after decalcification of the specimens. A comprehensive light and electron microscopic description of the location and fine structure of cutaneous sensory receptors of the trigeminal system was made by this means. The encapsulated and non-encapsulated Ruffini receptors, the types of other free receptors in the connective tissue and the Merkel cell receptor do not differ morphologically from those of higher mammals, whereas the pacinian-like corpuscle shows a unique organization of its outer core. This is composed of large perineural cells containing a unique reticulum of parallel-orientated endoplasmic membranes. Lamellated corpuscles, seen in isolation or in association with push rods, are numerous in the snout and in the tip of the tongue of echidna. Push rod receptor organs occur in the hairless skin of the bill with a very dense array at its rostral end and in the pseudopalatal ridges. Gland duct receptors are restricted to the skin adjacent to the nostrils and the mouth opening, including the pseudopalatal plates. Only about one quarter of the total number of 400 seromucous glands receive a sensory innervation of their intraepidermal duct segment. Within each innervated gland two types of receptor terminals are identified. The distributions of the different receptor types are mapped for different regions of the skin, the mucous membrane of the nasal and oral vestibule and the tip of the tongue. The fine structure of nerve terminals is discussed from a comparative anatomical point of view, and some speculations are made about possible transduction processes that underlie the known electrophysiological properties. The sensory organs such as the “push rod” and “gland duct receptor”, and most of their sensory terminals, are less differentiated in echidna snout than in the platypus (Ornithorhynchus anatinus) bill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00957899
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  • 12
    Electronic Resource
    Electronic Resource
    Immunocytochemical and ultrastructural studies of hyaline inclusions in sporadic motor neuron disease (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 295-301 
    Details
    ISSN: 1432-0533
    Keywords: Hyaline inclusions ; Motor neuron disease ; Amyotrophic lateral sclerosis ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We investigated hyaline inclusion bodies (HI) immunocytochemically and ultrastructurally in six cases of sporadic motor neuron disease (MND). All HI contained large amounts of ubiquitin and some HI were stained at the core or the center with anti-neurofilament antibody, with the surrounding halo unstained. No HI were stained with antibodies raised against cytoskeletal proteins such as high-molecular weight microtubule-associated proteins and phosphorylated tau. Ultrastructurally, HI were chiefly composed of filaments measuring about 20 nm in diameter thicker than neurofilaments, and contained fine granules and frequently one or more of four characteristic profiles, i.e., small electron-dense materials resembling Bunina bodies, bundles of tubular filaments measuring approximately 20 nm in diameter, large electron-dense cores, and focal accumulations of randomly arranged neurofilaments. Hyaline inclusions can be regarded as one of the characteristic markers for sporadic MND as well as familial amyotrophic lateral sclerosis. Hyaline inclusions have a markedly heterogeneous ultrastructure and, therefore, differences in immunoreactivity with antineurofilament antibodies are not unexpected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308815
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  • 13
    Electronic Resource
    Electronic Resource
    Meningiomas differentiating to arachnoid trabecular cells: a proposal for histological subtype “arachnoid trabecular cell meningioma” (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 327-330 
    Details
    ISSN: 1432-0533
    Keywords: Meningioma ; Microcystic meningioma ; Vacuolated meningioma ; Arachnoid trabecular cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three cases of meningiomas which had abundant small vacuoles in the tumor tissue are reported. By electron microscopy, the tumor cells exhibited long and thin processes, the tips of which were united by desmosomes. The tumor tissue was revealed to have wide extracellular spaces which corresponded to the vacuoles observed by light microscopy. In previous literature, various terms have been used when referring to this meningioma, such as microcystic meningioma or vacuolated meningioma. Since the ultrastructure of the tumor showed similarity to that of normal arachnoid trabecular cells, we propose to call the tumor “arachnoid trabecular cell meningioma” denoting its morphological nature clearly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296542
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  • 14
    Electronic Resource
    Electronic Resource
    Galactosialidosis: neuropathological findings in a case of the late-infantile type (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 331-339 
    Details
    ISSN: 1432-0533
    Keywords: Galactosialidosis ; Neuronal storage disease ; Neuropathology ; Ultrastructure ; Neuronal loss
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The neuropathological findings in a 13-year-old Japanese male showing decrease of sialidase and β-galactosidase activities are reported. The patient was the product of normal pregnancy to consanguineous parents. He started to sit at 8 months, stand at 20 months and walk at the age of 2; mental retardation, visual disturbance, cerebellar ataxia, myoclonus and epilepsy developed by the age of 10, and he died at 13. Neuropathological investigation revealed neuronal loss and storage. Severe loss of neurons was observed in the thalamus, globus pallidus, lateral geniculate body, gracile nucleus, Purkinje and retinal ganglion cells. Marked ballooning was seen in the Betz cells and neurons in the basal forebrain, the motor neurons in the cranial nerve nuclei and spinal cord, and in the trigeminal and spinal ganglia. The storage material varied in staining from region to region and from neuron to neuron. Electron microscopic investigation revealed a variety of intracytoplasmic and intranuclear inclusions: membranous cytoplasmic bodies, parallel, wavy-lamellar or tortuous tubular structures, lipofuscin-like irregular-shaped pleomorphic bodies, and cytoplasmic vacuoles with fine granules and lamellar materials. The severity of the neuronal loss did not seem to correlate with the amount of the storage materials, but with the presence of tortuous tubular inclusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296543
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  • 15
    Electronic Resource
    Electronic Resource
    Intramedullary secretory gangliocytoma (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 402-407 
    Details
    ISSN: 1432-0533
    Keywords: Gangliocytoma ; Ultrastructure ; Catecholamines ; Hypertension ; Spinal cord
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An 8-year-old boy developed severe systemic hypertension during resection of an intramedullary tumor. The histological, ultrastructural and immunocytochemical characteristics of the tumor are those of a gangliocytoma. Based on the demonstration of tyrosine hydroxylase in neuronal tumor cells, it is postulated that catecholamine secretion was responsible for the systemic hypertension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296552
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  • 16
    Electronic Resource
    Electronic Resource
    Immunocytochemical and ultrastructural studies of Werdnig-Hoffmann disease (1991)
    Springer
    Acta neuropathologica 81 (1991), S. 408-417 
    Details
    ISSN: 1432-0533
    Keywords: Werdnig-Hoffmann disease ; Immunocytochemistry ; Ultrastructure ; Cytoskeleton ; Ubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuronal alterations in two cases of Werdnig-Hoffmann disease (WH) were investigated immunocytochemically and ultrastructurally. Ballooned neurons (BNs) were found in anterior horn, Clarke's column, dorsal root ganglion and thalamus. Anti-phosphorylated neurofilament antibodies preferentially stained the peripheral perikarya and proximal neuronal processes of BNs, whereas anti-ubiquitin antibodies preferentially stained the central perikarya of BNs. Ultrastructurally, BNs showed degenerative changes ranging from a diffuse increase of neurofilaments to a centrally accentuated accumulation of mitochondria and vesicular or membranous profiles. Our studies suggest that ubiquitinated degradation products accumulate in the center of the BN's perikaryon and displace aberrantly phosphorylated neurofilaments to the periphery. BNs in WH probably reflect an intrinsic alteration in the metabolism of neurofilaments that is associated with regressive changes in the neuron and eventually neuronal death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293462
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  • 17
    Electronic Resource
    Electronic Resource
    The effect of denervation on the morphology of regenerating rat soleus muscles (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 21-32 
    Details
    ISSN: 1432-0533
    Keywords: Muscle ; Regeneration ; Denervation ; Ultrastructure ; Snake toxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study examines the level to which muscle regeneration proceeds in the absence of innervation. Regeneration was monitored in rat soleus muscles following localised injection of a snake toxin, notexin. Muscles which had been concomittantly denervated were compared with those that were normally innervated. Until 3–4 days following toxin administration regeneration is identical in both groups. The muscles contain new myotubes in place of the degenerated “parent” fibres. Thereafter, the non-denervated muscles grow rapidly and by 28 days their myofibres attain the size of those from the contralateral controls. Growth of denervated regenerating muscles, however, is retarded and is superseded by a gradual atrophy. In such muscles we further identify ultrastructural abnormalities from 7 days post-injection. These a re loss of individual myosin filaments and the presence of immature and abnormal configurations of the transverse system and triads. We, thus, conclude that innervation is an obligatory requirement for the restoration of normal myofibrillar and sarcotubular morphology, as well as growth, but is not necessary for the neo-formation of myofibres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310919
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  • 18
    Electronic Resource
    Electronic Resource
    Bone marrow transplant in a case of mucopolysaccharidosis I Scheie phenotype: skin ultrastructure before and after transplantation (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 33-38 
    Details
    ISSN: 1432-0533
    Keywords: MPS I-S ; Skin biopsy ; Ultrastructure ; Bone marrow transplant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An 11-year-old girl with mucopolysaccharidosis I Scheie phenotype (MPS I-S) received a bone marrow transplant (BMT) from her heterozygous HLA-identical LMC-non-reactive mother. Multidisciplinary studies were carried out and results evaluated 21 months after transplantation. Herein we report the ultrastructural findings pre-and post-BMT in skin. Multidisciplinary studies are commonly used to evaluate the benefits of metabolic correction following BMT in some MPS and other inherited metabolic disorders, and changes in morphology have been described in liver and few other tissues. In this case, we elected skin, since connective tissue is universally involved in MPS and is safely and easily obtainable. Comparison of skin biopsy specimens taken before and after BMT showed a considerable change in dermal fibroblast morphology, with marked reduction in cell size and the number and size of abnormal lysosomes, thus indicating the clearance of storage. Our results demonstrate that dermal cells respond to enzyme replacement therapy in MPS I-S, with the clearance of glycosaminoglycan lysosomal accumulation in connective tissue fibroblasts, which had near-normal morphology 21 months after BMT. Therefore, the practice of skin biopsy after BMT in MPS and other metabolic disorders in which dermal cells are involved should be encouraged.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310920
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  • 19
    Electronic Resource
    Electronic Resource
    Idiopathic prolactin cell hyperplasia of the pituitary mimicking prolactin cell adenoma: a morphological study including immunocytochemistry, electron microscopy, and in situ hybridization (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 147-151 
    Details
    ISSN: 1432-0533
    Keywords: Hyperplasia ; Pituitary ; Pathology ; Prolactin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Prolactin cell adenoma is the most frequently found lesion in surgically removed pituitaries of patients with hyperprolactinemia. However, in several instances, instead of prolactin cell adenoma, other lesions are encountered by morphological investigation. We report here the morphological findings in a patient with hyperprolactinemia who underwent transsphenoidal pituitary surgery for suspected prolactin cell adenoma. A morphological diagnosis of tumor could not be confirmed and massive diffuse prolactin cell hyperplasia was identified. The aim of this publication is to describe the lesion by histology, immunocytochemistry, electron microscopy, and in situ hybridization and to call attention to primary prolactin cell hyperplasia which can mimic prolactin cell adenoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293958
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  • 20
    Electronic Resource
    Electronic Resource
    Fulminant blastomycosis with blastomycotic infection of a cerebral glioma (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 420-424 
    Details
    ISSN: 1432-0533
    Keywords: Blastomycosis ; North American Blastomy-cosis ; Brain tumor ; Opportunistic infection ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Except for isolated case reports, blastomycosis has not been identified as a significant problem in immunosuppressed patients. We describe an unusual case with blastomycotic infection of a cerebral glioma in a 56-year-old man who underwent radiotherapy for his tumor and died of fulminant blastomycotic pneumonia. This is believed to be the first reported case of Blastomyces dermatitidis infection of a cerebral glioma. The light microscopic and ultrastructural features of B. dermatitidis, the giant forms of which were encountered in our patient, are described, and the role of immuno-suppression due to steroid therapy in the pathogenesis of this fulminant infection are reviewed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296555
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  • 21
    Electronic Resource
    Electronic Resource
    Scrapie inoculation of mice: light and electron microscopy of the superior colliculi (1991)
    Springer
    Acta neuropathologica 81 (1991), S. 562-571 
    Details
    ISSN: 1432-0533
    Keywords: Scrapie ; Ultrastructure ; Vacuolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural examination of the superior colliculi of mice intraocularly inoculated with the ME7 strain of scrapie showed vacuolation early in the course of infection. Brains were examined between 85–260 days after monocular inoculation with scrapie. The mean incubation period for the development of clinical disease was 302 days. Vacuolation was seen initially in the contralateral superior colliculus and subsequently in the ipsilateral colliculus. In coded trails light microscopical vacuolation was seen from 218 days but ultrastructural examination showed that sparse vacuoles were inconsistently present in either or both of the ipsilateral and contralateral colliculi from 85 days; frequent vacuoles were seen from 190 days. Scrapie-induced vacuoles were differentiated from vacuoles present in control tissue by the presence of loculation or by a limiting double membrane which showed protrusion or proliferation of the innermost lamella. Vacuolation was seen in neuronal perikarya, myelinated fibres, dendrites and axonal presynaptic terminals. Vacuoles of myelinated fibres were observed within myelin and possibly also in the inner tongue of oligodendroglial cytoplasm. Whorled membrane configurations were also seen. Tubulovesicular particles, 40 nm in diameter, were recognised in two scrapie-infected mice. It is suggested that some scrapie vacuoles arise as a result of incorporation of abnormal membrane into organelles, possibly mitochondria, in neuronal perikarya and neurites and probably also within oligodendroglial cytoplasm and myelin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310139
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  • 22
    Electronic Resource
    Electronic Resource
    Histopathogenesis of inflammatory linear verrucose epidermal naevus: histochemistry, immunohistochemistry and ultrastructure (1991)
    Springer
    Archives of dermatological research 283 (1991), S. 491-499 
    Details
    ISSN: 1432-069X
    Keywords: Inflammatory linear epidermal naevus ; Keratinization ; DACM ; Involucrin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Skin lesions of three patients with inflammatory linear verrucose epidermal naevus (ILVEN) were examined. Histologically, orthokeratosis and parakeratosis were alternately seen in the acanthotic epidermis. By N-(7-dimethylamino-4-methyl-3-coumarinyl)maleimide staining, the horny cells in the parakeratotic epidermis showed a cytoplasmic SH pattern and a weak membranous SS pattern. The orthokeratotic epidermis revealed an increased involucrin expression, whereas the parakeratotic epidermis showed almost no involucrin expression. Ultrastructurally, in the parakeratotic epidermis, the living keratinocytes had prominent Golgi apparatuses and vesicles in the cytoplasm. In the intercellular spaces in the upper spinous layer through to the lower horny layer, an electron dense, homogeneous substance was deposited. The cytoplasm of the horny cells was filled with keratin filaments and contained remnants of nucleus and cytoplasmic membrane structures, and some lipid droplets. The marginal band formation was incomplete. Most of these ultrastructural abnormalities were not found in the orthokeratotic epidermis. There are both similarities and differences in histopathogenesis of the parakeratotic epidermis between ILVEN and psoriasis. A unique finding was the lack of involucrin expression in the ILVEN parakeratotic epidermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371921
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  • 23
    Electronic Resource
    Electronic Resource
    The rhino mouse model: the effects of topically applied all-trans retinoic acid and CD271 on the fine structure of the epidermis and utricle wall of pseudocomedones (1991)
    Springer
    Archives of dermatological research 283 (1991), S. 100-107 
    Details
    ISSN: 1432-069X
    Keywords: Rhino mouse skin ; All-trans retinoic acid ; CD271 ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The histological and ultrastructural effects following 3 weeks' topical treatment with two agents (all-trans retinoic acid and a new synthetic retinoid-like substance, CD271) were evaluated on the epidermis and the epithelial wall of the pseudocomedones in rhino mouse skin. The comedolytic effects of these drugs were similar, and consisted of a reduction of the utricular diameter, with normalization of follicular units. Morphological examinations revealed a hyperplastic response with an increase in the number of cell layers of both epidermis and follicular epithelium, and modifications in keratinocyte differentiation. Ultrastructural changes in the epidermis and epithelial wall were observed mainly in the granular and horny layers, with increased desquamation, and a decrease in the cohesiveness of corneocytes. During the first week of treatment, some cutaneous toxic effects were noticed, but they normalized within two weeks. On the other hand, a fine granular material persisted in the intercellular spaces. It is confirmed that the skin of the rhino mouse is a good model for the evaluation of the comedolytic effects of drugs. Moreover, it reveals the specific effects of retinoids on epidermal differentiation. We have demonstrated that topically applied CD271 induces modifications similar to those obtained with all-trans retinoic acid. It is thus concluded that CD271 is a potentially effective anti-acne agent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371617
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  • 24
    Electronic Resource
    Electronic Resource
    Ultrastructural study of the skin in Sjögren — Larsson syndrome (1991)
    Springer
    Archives of dermatological research 283 (1991), S. 141-148 
    Details
    ISSN: 1432-069X
    Keywords: Sjögren ; Larsson syndrome ; Ichthyosis ; Ultrastructure ; Lamellar body ; Keratinization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ichthyosiform skin and the uninvolved skin of a 5-year-old Japanese female with Sjögren — Larsson syndrome were examined by light and electron microscopy to elucidate the keratinization disorder. Light microscopically, the epidermis of the ichthyosiform skin showed acanthosis, papillomatosis and hyperkeratosis. The horny cells had a basket-weave appearance. The granular cell layer was slightly thickened. Slight round cell infiltration and vascular dilatation were seen in the upper dermis. The uninvolved skin was histologically normal. Electron microscopically, in both ichthyosiform and uninolved skin, abnormal lamellar or membranous inclusions were present in the cytoplasm of horny cells of the epidermis. These inclusions appeared to be derived from some of the lamellar bodies and/or abnormal membranous structures found in the cytoplasm of spinous and granular cells. Mitochondria in the epidermal basal cells were more numerous in the ichthyosiform skin than in the uninvolved skin. These findings indicate that, whether the skin is involved or not, the epidermis of the patient with this disorder may always have a structural abnormality, which may be genetically determined. Local environmental factors may play a role in inducing the acanthosis and papillomatosis of the epidermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372053
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  • 25
    Electronic Resource
    Electronic Resource
    Are accessory nuclei involved in the establishment of developmental gradients in hymenopteran oocytes? (1991)
    Springer
    Development genes and evolution 199 (1991), S. 423-426 
    Details
    ISSN: 1432-041X
    Keywords: Oogenesis ; Accessory nuclei ; Developmental gradients ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the oocytes ofTenthredo olivacea, accessory nuclei (AN) are formed by budding from the nuclear envelope of the oocyte nucleus. Newly formed AN contain electron-dense material of nuclear origin and are surrounded by a double envelope devoid of pores. Such structures are subsequently transported to the peripheral ooplasm (periplasm), where they grow to reach a final diameter of 5 µm. In the envelopes of advanced AN nuclear pores arise. Through these pores “nuage” material is extruded into the surrounding periplasm. These findings are discussed with respect to a possible involvement of AN in the establishment of developmental gradients in hymenopteran oocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01705853
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  • 26
    Electronic Resource
    Electronic Resource
    The origin of the nascent blastocoele in preimplantation mouse embryos ultrastructural cytochemistry and effect of chloroquine (1991)
    Springer
    Development genes and evolution 200 (1991), S. 77-85 
    Details
    ISSN: 1432-041X
    Keywords: Lysosomes ; Ultrastructure ; Chloroquine ; Blastocyst ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mouse morulae are known to undergo cavitation as soon as some external cells have entered the sixth cell cycle (Garbutt et al. 1987). Since the early cytological features of cavitation are still unclear, we undertook a careful ultrastructural analysis of late morulae-nascent blastocysts. In addition, since maturation of lysosomes might be involved in the first step of cavity formation, we focused our attention on these organelles by means of the cytochemical localization of trimetaphosphatase activity and by the study of the effects of chloroquine on precavitation embryos. Our results suggest that cavitation starts in a few external cells (presumably competent cells entering the sixth cell cycle), by the chloroquine-sensitive formation of degradative autophagic vacuoles engulfing lipid droplets and vacuoles containing osmiophilic material. These complex structures enlarge (as a result of lipid metabolism?) and so transform into intrablastomeric cavities which, by means of a membrane fusion process, very rapidly become extracellular cavities that coalesce. The abembryonic pole of the blastocyst is determined in this way. Moreover, we suggest that the juxtacoelic cytoplasmic processes covering the inner cell mass (ICM) cells, which are known to restrict the expression of their totipotency during early cavitation (Fleming et al. 1984), are the latest remnants of the walls of the growing intrablastomeric cavities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637187
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  • 27
    Electronic Resource
    Electronic Resource
    Contributions of sodium and chloride to ultrastructural damage after dendrotomy (1991)
    Springer
    Experimental brain research 86 (1991), S. 60-72 
    Details
    ISSN: 1432-1106
    Keywords: Trauma ; Neuron ; Sodium ; Chloride ; Ultrastructure ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To determine the contributions of sodium and chloride to ultrastructural changes after mechanical injury, we amputated primary dendrites of cultured mouse spinal neurons in low calcium medium in which sodium chloride had been replaced with either choline chloride or sodium isethionate or sodium propionate. Uninjured cultured neurons were also exposed to the sodium ionophore, monensin. A third set of neurons was injured in medium in which all sodium and calcium chloride had been replaced with sucrose. Neurons injured in low-calcium, low-sodium medium exhibited few ultrastructural changes, except very near the lesion, where there was some dilation of mitochondria and cisternae of the smooth endoplasmic reticulum (SER). Mitochondria in other regions of the neurons developed an electron opaque matrix, and those nearer to the lesion converted to the condensed configuration, characterized by expanded intracristal spaces as well as a dense matrix. If sodium but not chloride was present in the medium, there was some dilation of the Golgi cisternae after injury, as well as some increased electron opacity of the mitochondria. Monensin treated neurons also exhibited dilation of the Golgi cisternae. Neurons injured in sucrose-substituted medium showed none of the changes associated with injury in normal culture medium. These results indicate that sodium influx through the lesion is involved in the dilation of the SER, which is seen even in low-calcium medium, and that a permeant anion, such as chloride, is also involved. This dilation of the SER may result from uptake of calcium released from mitochondria in response to elevated cytosolic sodium. Dilation of the Golgi cisternae appears to be a response only to elevated intracellular sodium. Condensation of the mitochondria after injury is thought to be due to increased demands for ATP synthesis and may involve a “futile cycling” of calcium across the mitochondrial membrane, involving sodium-mediated calcium release in response to elevated intracellular calcium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231040
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  • 28
    Electronic Resource
    Electronic Resource
    Secretory tapetum of Brassica oleracea L.: polarity and ultrastructural features (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 28-35 
    Details
    ISSN: 1432-2145
    Keywords: Tapetal cells ; Brassica oleracea L ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of the secretory, binucleate tapetum of Brassica oleracea in the micro spore mother cell (MMC) stage through to the mature pollen stage is reported. The tapetal cells differentiate as highly specialized cells whose development is involved in lipid accumulation in their final stage. They start breaking down just before anther dehiscence. Nuclei with dispersed chromatin, large nucleoli and many ribosomes in the cytoplasm characterize the tapetal cells. The wall-bearing tapetum phase ends at the tetrade stage. The dissolution of tapetal walls begins from the inner tangential wall oriented towards the loculus and proceeds gradually along the radial walls to the outer tangential one. The plasmodesmata transversing the radial walls between tapetal cells persist until the mature microspore, long after loss of the inner tangential wall. After wall dissolution, the tapetal protoplasts retain their integrity and position within the anther locule. The tapetal cell membrane is in direct contact with the exine of the microspores/pollen grains and forms tubular evaginations that increase its surface area and appear to be involved in the translocation of solutes from the tapetal cells to the microspores/ pollen grains. The tapetal cells exhibit a polarity expressed by spatial differentiation in the radial direction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194568
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  • 29
    Electronic Resource
    Electronic Resource
    Brassica napus pollen development during generative cell and sperm cell formation (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 176-181 
    Details
    ISSN: 1432-2145
    Keywords: Pollen ; Brassica napus ; Mitoses ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Brassica napus pollen development during the formation of the generative cell and sperm cells is analysed with light and electron microscopy. The generative cell is formed as a small lenticular cell attached to the intine, as a result of the unequal first mitosis. After detaching itself from the intine, the generative cell becomes spherical, and its wall morphology changes. Simultaneously, the vegetative nucleus enlarges, becomes euchromatic and forms a large nucleolus. In addition, the cytoplasm of the vegetative cell develops a complex ultrastructure that is characterized by an extensive RER organized in stacks, numerous dictyosomes and Golgi vesicles and a large quantity of lipid bodies. Microbodies, which are present at the mature stage, are not yet formed. The generative cell undergoes an equal division which results in two spindle-shaped sperm cells. This cell division occurs through the concerted action of cell constriction and cell plate formation. The two sperm cells remain enveloped within one continuous vegetative plasma membrane. One sperm cell becomes anchored onto the vegetative nucleus by a long extension enclosed within a deep invagination of the vegetative nucleus. Plastid inheritance appears to be strictly maternal since the sperm cells do not contain plastids; plastids are excluded from the generative cell even in the first mitosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190001
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  • 30
    Electronic Resource
    Electronic Resource
    Ultrastructure of the micropyle and its relationship to pollen tube growth and synergid degeneration in sunflower (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 166-175 
    Details
    ISSN: 1432-2145
    Keywords: Helianthus annuus ; Ultrastructure ; Micropyle ; Pollen tube ; Synergid degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ultrastructural studies made on the micropyle of sunflower before and after pollination resulted in the following observations. (1) The micropyle is closed instead of a hole or canal. The inner epidermis of the integument on both sides of the micropyle is in close contact at the apex of the ovule. The boundary between the two sides consists of two layers of epidermal cuticle. (2) The micropyle contains a transmitting tissue. The micropyle is composed of an intercellular matrix produced by the epidermal cells of the integument. (3) The micropyle is asymmetrical, and is much wider on the side proximal to the funicle. On the funicle side the cells adjacent to the micropyle are similar to those of the transmitting tissue: they have large amounts of intercellular matrix and contain abundant dictyosomes, rough ER, and starch grains, and provide an appropriate environment for growth of the pollen tubes. The cells distal to the funicle are rich in rough ER and lipid bodies; they lack large intercellular spaces. (4) The micropyle is variable in the axial direction, i.e., it is much larger and more asymmetric at the level distal to the embryo sac than at a level close to the embryo sac. After pollination, one to four pollen tubes are seen in a micropyle. During their passage through the micropyle, most pollen tubes are restricted to the side proximal to the funicle. There is a greater tendency (81%) for the degenerate synergid to be located toward the funicle, i.e., at the same side as the pollen tube pathway. The data indicate a close relationship between micropyle organization, orientation of pollen tube growth, and synergid degeneration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190000
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  • 31
    Electronic Resource
    Electronic Resource
    Sperm cells of the pollen tubes of Brassica: Ultrastructure and isolation (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 226-234 
    Details
    ISSN: 1432-2145
    Keywords: Male germ unit ; Sperm cells ; Isolation ; Pollen tubes ; Brassica napus ; Pollen-tube inner plasma membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sperm cells of pollen tubes grown both in vivo and in vitro form a male germ unit. Extensions from both sperm cells of each pollen tube are closely associated with the tube nucleus. A high yield (2.7 × 104. 20 mg−1 pollen grains germinated) of intact sperm cells was obtained following release by osmotic shock from pollen tubes grown in vitro. Structural integrity of isolated sperm was maintained by isolation at low temperature in an osmotically balanced medium. At 4° C many isolated sperm pairs were still enclosed within the pollentube inner plasma membrane. Sperm cells not enclosed within this membrane no longer remained connected as a pair. During isolation vesicles formed on the sperm cell surface from disruption of the fibrillar components bridging the periplasmic space. Both in the pollen tube and after isolation the sperm nucleus is in close association with at least one region of the sperm plasma membrane. Sperm isolated at room temperature showed the presence of nucleopores, and nuclei were euchromatic, instead of heterochromatic as in intact sperm in the pollen tube.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190009
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  • 32
    Electronic Resource
    Electronic Resource
    Microsporogenesis and tapetal development in fertile and cytoplasmic male-sterile sugar beet (Beta vulgaris L.) (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 215-225 
    Details
    ISSN: 1432-2145
    Keywords: Cytoplasmic male sterility ; Beta vulgaris ; Microsporogenesis ; Tapetum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of sporogenous and tapetal cells in the anthers of male-fertile and cytoplasmic male-sterile sugar beet (Beta vulgaris L.) plants was studied using light and transmission electron microscopy. In general, male-sterile anthers showed a much greater variability in developmental pattern than male-fertile anthers. The earliest deviation from normal anther development was observed to occur in sterile anthers at meiotic early prophase: there was a degeneration or irregular proliferation of the tapetal cells. Other early aberrant events were the occurrence of numerous small vesicles in the microspore mother cells (MMC) and a disorganized chromatin condensation. Deviations that occurred in sterile anthers at later developmental stages included: (1) less distinct inner structures in the mitochondria of both MMC and tapetal cells from middle prophase onwards. (2) dilated ER and nuclear membranes at MMC prophase, in some cases associated with the formation of protein bodies. (3) breakdown of cell walls in MMCs and tapetal cells at late meiotic prophase. (4) no massive increase in tapetal ER at the tetrad stage. (5) a general dissolution of membranes, first in the MMC, then in the tapetum. (6) abortion of microspores and the occurrence of a plasmodial tapetum in anthers reaching the microspore stage. (7) no distinct degeneration of tapetal cells after microspore formation. Thus, it seems that the factors that lead to abortive microsporogenesis are structurally expressed at widely different times during anther development. Aberrant patterns are not restricted to the tetrad stage but occur at early prophase.
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    URL: http://dx.doi.org/10.1007/BF00190008
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  • 33
    Electronic Resource
    Electronic Resource
    Fluoride effects on leaf cell ultrastructure of olive trees growing in the vicinity of the Aluminium Factory of Greece (1991)
    Springer
    Trees 5 (1991), S. 83-89 
    Details
    ISSN: 1432-2285
    Keywords: Air pollutants ; Chloroplasts ; Fluoride ; Olive tree leaves ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Leaves of olive trees growing in the vicinity of the Aluminium Factory of Greece were ultrastructurally investigated in order to determine any malformations caused by environmental air pollutants, especially hydrogen fluoride, in comparison with control samples and normal seasonal senescence. Estimation of some elements accumulated by these leaves showed that they contained high amounts of F and Al attributable to the operation of the nearby factory. The most seriously effected cell components were found to be the mesophyll chloroplasts that show a dilation of the intrathylakoid space, increase of the number of plastoglobuli, discoloration of plastoglobuli, accumulation of large starch grains and an overall disorganized appearance of the organelle. The nuclear crystalloid inclusions have unusual shapes, while the vacuoles contain a fibrillar/granular material that increases their electron density. It is concluded that the ultrastructural malformations are caused by a combination of environmental stresses and air pollutants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227489
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  • 34
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    Electronic Resource
    Different epithelia in the distal human male urethra (1991)
    Springer
    Cell & tissue research 264 (1991), S. 23-32 
    Details
    ISSN: 1432-0878
    Keywords: Male urethra ; Urethral epithelium ; Immunocytochemistry ; Ultrastructure ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distal segment of the human male urethra, in particular the fossa navicularis, was studied with light- and electron microscopy as well as by means of histochemical and immunocytochemical methods. The fossa navicularis of the urethra contains a circumscribed zone of extremely thick, non-keratinized stratified squamous epithelium composed of cells containing a large amount of glycogen. These cells lack acid phosphatase activity and lysozyme-like immunoreactivity, both of which can be demonstrated to varying extents in the other zones of the distal male urethra. These glycogen-rich cells are considered to be the substrate for an endogenous flora of lactobacteria, whereas the acid-phosphatase activity and the lysozyme-like immunoreactivity indicate the presence of macrophages and the secretion of bactericidal agents at the epithelial surface. These observations suggest that the different zones with heterogeneous properties in the distal male urethra probably represent a defense system against the invasion of pathogenic microorganisms. Moreover, the glycogen-rich zone, which resembles the glycogen-rich epithelium of the vagina, is estrogen-dependent. This is demonstrated in cases of sex reversal in which after long-lasting estrogen treatment the glycogen-rich zone becomes extremely extended by displacement of the neighbouring epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305719
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  • 35
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    Electronic Resource
    Ultrastructure of melatonin-responsive cells in the ovine pars tuberalis (1991)
    Springer
    Cell & tissue research 263 (1991), S. 529-534 
    Details
    ISSN: 1432-0878
    Keywords: Melatonin ; Pituitary gland, pars tuberalis ; Secretory cells ; Cyclic AMP ; Ultrastructure ; Cell culture ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Functional receptors for melatonin have been localized and characterized on the pars tuberalis (PT) of a number of mammalian species, but the cell-type responsive to melatonin is unknown. The ultrastructure of the ovine pars tuberalis has been examined and these findings correlated with the functional response of the gland to melatonin. This study revealed that two secretory cell types predominate in the ovine PT, which differ in the abundance of dense-core granules. The most abundant of the cells are either agranular or very sparsely granulated and represent 90% of the total population, with the remaining 10% being composed of cells with abundant dense-core vesicles. Few follicular cells were observed. This ratio of secretory cell-types persisted in primary culture, with the two types non-separable by Percoll gradient centrifugation. Using forskolin, as a non-specific stimulant of adenylate cyclase, melatonin was shown to inhibit the formation of cyclic AMP by 80–90% in cells both before and after Percoll centrifugation. The results demonstrate that the agranular secretory cells of the ovine pars tuberalis are the melatonin responsive cell-type of this gland.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327285
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  • 36
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    Electronic Resource
    Ultrastructure and distribution of somatostatin-like immunoreactive neurons and nerve fibres in the coeliac ganglion of cats (1991)
    Springer
    Cell & tissue research 263 (1991), S. 567-572 
    Details
    ISSN: 1432-0878
    Keywords: Somatostatin ; Coeliac ganglion ; Autonomic innervation ; Ultrastructure ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Somatostatin-like immunoreactivity was localized in nerve cell bodies and nerve terminals in the cat coeliac ganglion. Two types of somatostatin-immunoreactive cell bodies were revealed, the first being large (diameter 35 μm), numerous and weakly labelled, where—as the second was considerably smaller (diameter 10.4 μm), sparsely distributed and heavily stained. The immunoreactive nerve terminals were in synaptic contact with many immunonegative large neurons and dendrites. However, in a few cases, somatostatin-immunoreactive nerve terminals could also be observed on the surface of lightly stained neurons. Transection of vagal or mesenteric nerve failed to affect the distribution or density of somatostatin-like immunoreactive nerve terminals. These results demonstrate the existence of a synaptic input to the principal neurons of the coeliac ganglion of the cat by somatostatin-containing nerve terminals and suggest that this peptide may act as a neuromodulator or neurotransmitter. It is proposed that somatostatin-positive neurons provide intrinsic projections to other somatostatin-positive and to somatostatin-negative neurons throughout the coeliac ganglion, thereby creating a complex interneuronal system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327290
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  • 37
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    Electronic Resource
    Islets of preadipocytes highly committed to differentiation in cultures of adherent rat adipocytes (1991)
    Springer
    Cell & tissue research 264 (1991), S. 243-251 
    Details
    ISSN: 1432-0878
    Keywords: Preadipocytes ; Adipocyte precursor cells ; Adipose tissue ; Differentiation-cell cultures ; Ultrastructure ; Rat (Fischer 344)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cultures of adherent mature adipocytes, obtained from collagenase-digests of adipose tissue of the rat, invaribly contain rapidly proliferating, fibroblastlike cells despite the washing and centrifugation procedures empolyed during isolation of the fat cells. Such spindle-like cells originate from low-density structures, which we term “islets”, that are present, together with the mature adipocytes, in the floating layer of the digest of adipose tissue. Islets are found in preparations from adult (3–4 months old) as well as aging (17–24 months old) rats. By light-and electron microscopy, the islets appear as clusters of closely associated cells containing a variable amount of lipid-like material. Cells of endothelial or pericytic origin are also present in the islets. Within a few hours of culture, the islets give rise to those spindle-like cells that have been seen to proliferate in the cultures. By 36–48 hours, such cells begin to accumulate lipid droplets and, by 150 hours, assume the morphology of small mature adipocytes (diameter 20–35 μm) with a large central lipid droplet. The pattern of differentiation of these cells recalls that of preadipocytes derived from the stromal-vascular fraction of adipose tissue digests. Nonetheless, the extent and rapidity of their adipose conversion, as well as the culture conditions necessary for differentiation, are different and suggest that these cells are a substantially uniform subpopulation of adipocyte-precursor cells highly committed to differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00313961
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  • 38
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    Electronic Resource
    Postnatal changes in the ultrastructure of the rat olfactory epithelium: the supranuclear region of the supporting cells (1991)
    Springer
    Cell & tissue research 265 (1991), S. 193-196 
    Details
    ISSN: 1432-0878
    Keywords: Postnatal development ; Olfactory epithelium ; Supporting cells ; Receptor cell dendrites ; Ultrastructure ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present electron-microscopical study reports ultrastructural changes occurring in the supranuclear region of the supporting cells of the rat olfactory epithelium during the first 16 days of postnatal life. These changes are concerned with the enclosure of receptor cell dendrites and an increase in the amount of smooth endoplasmic reticulum, which has a specific distribution in the supporting cell. An increase in microvillous projections at the free cell surface is also observed. Moreover, this report demonstrates that the cytoarchitecture of the apical portion of the olfactory epithelium at the 16th day of postnatal life is similar, with respect to the relationship between supporting cells and receptor cell dendrites, to that of adult animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318154
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  • 39
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    Electronic Resource
    Diversity of ultrastructure in different phenotypes of cultured microvessel endothelial cells isolated from bovine corpus luteum (1991)
    Springer
    Cell & tissue research 266 (1991), S. 37-49 
    Details
    ISSN: 1432-0878
    Keywords: Microvessel endothelial cells ; Cell culture ; Corpus luteum ; Ultrastructure ; Cow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Five different types of cultured microvessel endothelial cells defined by use of light microscopy and scanning electron microscopy in a preceding study were investigated by transmission electron microscopy. Type-1 cells displayed a deep invagination of the cell membrane or a single cilium. Granules of low electron density were abundant. A perinuclear ring of intermediate filaments occurred. Cultures of type-2 cells were subdivided into phenotype A, reminiscent of cell-type 1, and into phenotype B, assumed to be vascular smooth muscle cells. Many highly electron-dense granules appeared in late postconfluent cultures of both phenotypes. Cell-type 3 was conspicuous because of a large intracytoplasmic vacuole. Lysosomes with curvilinear bodies were found in cell-types 3 and 4. Both cell types developed a peripheral regular network of microfilaments. Cell-type 5 showed vesiculation of the rough endoplasmic reticulum, lipid droplets and a peripheral felt-like belt of microfilaments. Tubular forms seen in late postconfluent cultures of cell-types 1 to 3 displayed a core of extracellular matrix. Pseudotubular forms of cell-type 4 contained apoptotic bodies. Thus, as seen at the ultrastructural level, different features are maintained by cultured microvessel endothelial cells, suggesting that they have different inherent properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00678709
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  • 40
    Electronic Resource
    Electronic Resource
    Effect of cytokines on thymic hematopoietic precursors (1991)
    Springer
    Cell & tissue research 264 (1991), S. 369-375 
    Details
    ISSN: 1432-0878
    Keywords: Thymus ; CD4- ; CD8- ; thymocyte ; Thymic hematopoietic precursors ; Cytokines ; Ultrastructure ; Mouse (DBA/2, H-2d)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We have previously shown that the interaction of thymocytes with thymic accessory cells (macrophages and/or interdigitating cells) is one of the factors required for thymocyte activation. Precursors of both thymic accessory cell and thymocytes are included in the CD4- CD8- Mac-1- Ia- subpopulation, and their respective maturation and/or activation may be modulated by granulocyte-macrophage colony-stimulating factor, interleukin 1 and interleukin 2. When CD4- CD8- thymic cells are activated with granulocyte-macrophage colony-stimulating factor plus interleukin 2, both macrophages and interdigitating-like cells are present, as shown by electron microscopy. When activated with interleukin 1 plus interleukin 2, the interdigitating-like cells is the only accessory cell present. In both culture conditions, large clusters are formed between interdigitating cells and lymphoid cells. These results have led us to propose two-step signals for thymocyte proliferation: first, the maturation of macrophages under granulocyte-macrophage colony-stimulating factor control and the production of interleukin 1, and secondly, the maturation of interdigitating cells under interleukin 1 control, their clustering with thymocytes which are then activated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00313976
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  • 41
    Electronic Resource
    Electronic Resource
    The fine structure of lamellate cells in the brain of amphioxus (Branchiostoma lanceolatum, Cephalochordata) (1991)
    Springer
    Cell & tissue research 263 (1991), S. 597-600 
    Details
    ISSN: 1432-0878
    Keywords: Lamellate cell ; Ultrastructure ; Ciliary photoreceptors ; Nervous system, prochordates ; Branchiostoma lanceolatum (Acrania)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lamellate cells of amphioxus have round nuclei, and cytoplasm with many mitochondria and a large amount of glycogen. Each of these cells projects a highly modified, branched cilium into the central canal, where it characteristically forms lamellar structures. Primary branches and secondary lamellae often contain accessory microtubules that are not derived from the axonema. The functional and evolutionary significance of this cell type is discussed in relation to the ciliary photoreceptors found in other chordates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327295
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  • 42
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    Electronic Resource
    Cell types in the fetal pars tuberalis of the human adenohypophysis at mid-gestation (1991)
    Springer
    Cell & tissue research 264 (1991), S. 161-165 
    Details
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Pars tuberalis ; Ultrastructure ; Immunohistochemistry ; Fetal ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pars tuberalis of the adenohypophysis was investigated in three human fetuses at mid-gestation by electron microscopy or immunohistochemistry. In addition to gonadotrophs and thyrotrophs, identified by immunohistochemistry and ultrastructural morphology, electron microscopy revealed the existence of an additional differentiated cell type closely resembling “pars tuberalis-specific” cells known from other species. The role of this cell type in the human endocrine regulation remains to be elucidated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305734
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  • 43
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    Electronic Resource
    Effect of 1,10-phenanthroline on ultrastructure of pea leaves (1991)
    Springer
    Protoplasma 161 (1991), S. 23-30 
    Details
    ISSN: 1615-6102
    Keywords: 1,10-Phenanthroline ; Photodynamic herbicides ; Pisum sativum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have examined ultrastructural changes of mesophyll cells in pea leaves induced by the photodynamic herbicide 1,10-phenanthroline (Phe). Dark incubation of pea plants did not cause any damage in plants or changes in the ultrastructure of mesophyll cells. Two hours of illumination after pretreatment with Phe caused photooxidative damage in plant but was not sufficient to markedly change the ultrastructure, although dilation of endoplasmic reticulum (ER) cisternae occurred. Illumination for 12 h caused inhibition of grana formation in pretreated plants. These ultrastructural changes and the inhibition of chlorophyll (Chl) accumulation may be due to the inhibition of transport of certain proteins to the plastids, diminished accumulation of chlorophyll proteins (e.g., LHCP) and a decrease in activity of the chlorophyll synthetase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01328894
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  • 44
    Electronic Resource
    Electronic Resource
    Intercellular permeability inAbutilon nectary trichomes (1991)
    Springer
    Protoplasma 161 (1991), S. 150-159 
    Details
    ISSN: 1615-6102
    Keywords: Abutilon ; Lucifer Yellow ; Microinjection ; Nectary ; Transport ; Trichome ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Intercellular transport was examined in nectary hairs ofAbutilon slriatum var.thompsonii using dye-uptake and microinjection followed by fluorescence and electron microscopy. Dye-uptake experiments demonstrated that both Lucifer Yellow CH (LYCH) and diaminobenzidine (DAB) move centrifugally along an apoplastic pathway from the sepellary tissue towards the tip cell. Further, fluorescence of LYCH could also be detected inside the cells of the nectary trichome. When LYCH or LYCH/DAB were microinjected into the tip cell, the dye spread in a centripetal direction towards the stalk cell. Electron microscopical investigations of microinjected nectary hairs revealed numerous electron-opaque globules in the cytoplasm of the nectary hair cells. In addition, multivesicular bodies, nuclei with opaque regions and changes in the rough endoplasmic reticulum (RER) were seen in nectary hair cells even at very low concentrations of injected dye. Ultrastructural investigations provided evidence for cytological changes in microinjected nectary hairs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01322727
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  • 45
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    Electronic Resource
    Ultrastructure of the vegetative organisation and initial stages of silica plate deposition in the soil testate amoebaCorythion dubium (1991)
    Springer
    Protoplasma 163 (1991), S. 136-144 
    Details
    ISSN: 1615-6102
    Keywords: Corythion dubium ; Silica deposition ; Testate amoeba ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The siliceous body plates ofCorythion dubium are bound by a band of organic cement which is thickest at the lateral margins. The anterior vacuolar cytoplasm is separated by a pigment zone, which forms a dark band in the mid-body region, from the compact posterior region containing a typical vesicular nucleus surrounded by a region of dense endoplasmic reticulum. A pellicular basket of microtubules surrounds the posterior cytoplasm. The large Golgi complex lies between the nucleus and the fundus. Numerous coated and uncoated vesicles from the Golgi cisternae are seen in the peripheral cytoplasm alongside developing plates. These small siliceous plates are enclosed in silicon deposition vesicles lying in surface ruffles of the plasmalemma, often in association with a pair of microtubules. Observations are made on the formation of these vesicles and the early stages of silica deposition. A comparison is drawn between silica deposition inC. dubium and choanoflagellates where there is a similar association between silicon deposition vesicles and microtubules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01323337
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  • 46
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    Effects of heat shock and thermoadaptation on the ultrastructure of cowpea (Vigna unguiculata) cells (1991)
    Springer
    Protoplasma 163 (1991), S. 125-135 
    Details
    ISSN: 1615-6102
    Keywords: Cowpea ; Heat shock ; Thermoadaptation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Suspension culture cells of cowpea (Vigna unguiculata) were examined using transmission electron microscopy to characterize morphological changes associated with hyperthermal stress. Cultures maintained at 26°C (unadapted cells) and 38°C (thermoadapted cells) were examined before and after exposure to elevated temperatures of 34°C and 45°C, respectively. Observations indicate that while there were significant ultrastructural differences between unadapted and thermoadapted cells, the following structural modifications in response to heat stress were observed in cells of both cultures: (a) almost a complete loss of polyribosomes, rough ER, and dictyosomes, (b) migration of intracellular waste material (presumably proteinaceous in composition) into the cell vacuole, (c) swelling of the nucleolus with assumed accumulation of preribosomal RNP granules, and (d) retraction of the tonoplast from the cytoplasm into the vacuoles of some cells. Heat shock granules (two size classes) were observed in the cytoplasm of stressed thermoadapted cells along with hollow-cored granules within the leucoplasts. Apart from a few minor differences, the morphological modifications that were made in apparent response to hyperthermal stress were remarkably similar in both cultures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01323336
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  • 47
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    Electronic Resource
    Ontogeny and ultrastructure of spontaneous nodules in alfalfa (Medicago sativa) (1991)
    Springer
    Protoplasma 162 (1991), S. 1-11 
    Details
    ISSN: 1615-6102
    Keywords: Rhizobium meliloti ; Development ; Symbiosis ; Nitrogen fixation ; Ultrastructure ; Spontaneous nodule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of spontaneous nodules, formed in the absence ofRhizobium and combined nitrogen, on alfalfa (Medicago sativa L. cv. Vernal) was investigated at the light and electron microscopic level and compared to that ofRhizobium-induced normal nodules. Spontaneous nodules were initiated from cortical cell divisions in the inner cortex next to the endodermis, i.e., the site of normal nodule development. These nodules, on uninoculated roots, were white multilobed structures, histologically composed of nodule meristems, cortex, endodermis, central zone and vascular strands. Nodules were devoid of intercellular or intracellular bacteria confirming microbiological tests. Early development of spontaneous nodules was initiated by series of anticlinal followed by periclinal divisions of dedifferentiated cells in the inner cortex of the root. These cells formed the nodular meristem from which the nodule developed. The cells in the nodule meristems divided unequally and differentiated into two distinct cell types, one larger type being filled with numerous membrane-bound starch grains, and the other smaller type with very few starch grains. There were no infection threads or bacteria in the spontaneous nodules at any stage of development. This size differentiation is suggestive of the different cell sizes seen inRhizobium-induced nodules, where the larger cell type harbours the invading bacteria and the smaller type is essential in supportive metabolic roles. The ontogenic studies further support the claim that these structures are nodules rather than aberrant lateral roots, and that plant possess all the genetic information needed to develop a nodule with distinct cell types. Our results suggest that bacteria and therefore theirnod genes are not necessarily involved in the ontogeny and morphogenesis of spontaneous and normal nodules in alfalfa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01403895
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  • 48
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    Electronic Resource
    The occurrence and ultrastructure of a mechanoreceptor in the human cricopharyngeus muscle (1991)
    Springer
    European archives of oto-rhino-laryngology and head & neck 248 (1991), S. 144-146 
    Details
    ISSN: 1434-4726
    Keywords: Cricopharyngeus muscle ; Golgi tendon organ ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An encapsulated nerve structure resembling the Golgi tendon organ was found in a human cricopharyngeus muscle near the cricoid cartilage where muscle fibers terminate. The capsule consisted of lamellated flattened cells with a basal lamina. Capsular cells separated the lumen into small compartments which contained myelinated and/or nonmyelinated nerve fibers. Nonmyelinated nerve fibers were also found in the interlamellar spaces of the capsular cells. Some nonmyelinated nerve fibers were dilated and contained abundant mitochondria, being partly surrounded by a Schwann cell sheath and embedded in collagen bundles. These features indicate that the nerve structure is a mechanoreceptor similar to the Golgi tendon organ. Its location and structure indicate that it is placed to detect the tension of the cricopharyngeus muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178924
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  • 49
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    Electronic Resource
    Further observations on the phagocytosis of Candida albicans by Hamster and Human Oocytes (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 28 (1991), S. 79-84 
    Details
    ISSN: 1040-452X
    Keywords: Yeast ; Ultrastructure ; Oocyte infection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Pathogenic yeast, Candida albicans, were incubated with hamster and human oocytes for up to 21 hours in order to determine the nature and time course of phagocytosis of these organisms. Aliquotes of the interacting cells were taken at various time intervals for electron microscopic examination. Some specimens had their zona pellucidae enzymatically removed prior to incubation with yeast, and these specimens showed the most extensive interaction and phagocytosis of Candida. The zona pellucida appears to be an effective barrier to yeast, at least over the time span studied. The observations are consistent with the hypothesis of an initial attachment of yeast via a surface component to oocyte microvilli followed by phagocytic uptake into an endosome. There is no compelling evidence of lysosomal degradation of the yeast over the time course of this study; however, the oocytes appear to undergo some degenerative changes at long incubation times.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080280113
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  • 50
    Electronic Resource
    Electronic Resource
    Two major acrosomal proteins act on different parts of the oocyte vitelline coat in the abalone, Haliotis discus (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 28 (1991), S. 189-198 
    Details
    ISSN: 1040-452X
    Keywords: Vitelline coat lysis ; Lysins ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Two proteins of molecular weights 20,000 (20K) and 15,500 (15.5K) are the major soluble substances released from the acrosomal vesicle of the abalone, Haliotis discus, spermatozoon. A crude preparation of them has been shown to possess lytic activity on the oocyte vitelline coat (VC). To elucidate the role(s) of each acrosomal protein (AP) in VC lysis, oocytes were examined after treatment with various AP preparations. The VC, which is about 1 μm thick, is composed of thin outer and inner electron-dense layers and a thick main layer of a fine filamentous feltwork. When oocytes were treated with a crude preparation containing both APs, the outer layer disappeared and the feltwork of the main layer loosened extensively. A preparation containing predominantly the 20K AP dissolved the outer layer completely and the main layer to some extent, whereas another preparation containing predominantly the 15.5K AP caused loosening of the main layer without alteration of the outer layer, suggesting that the 20K AP acts on the outer layer, whereas the 15.5K AP acts on the main layer. However, when purified, each AP by itself failed to dissolve the VC, although lysis occurred in a 1:1 mixture of these preparations. Moreover, when the oocytes were pretreated with the 20K AP and thoroughly washed, the 15.5K AP alone could induce lysis. These results suggest that the lysis of the outer layer requires both APs but not simulataneously. The 15.5K AP, which is located posteriorly in the acrosomal vesicle, must be released to act on the VC following the action of the 20K AP.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080280213
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  • 51
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    A monoclonal antibody, MN13, that recognizes specifically a novel substance between the postacrosomal sheath and the overlying plasma membrane in the mammalian sperm head (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 29 (1991), S. 289-293 
    Details
    ISSN: 1040-452X
    Keywords: Postacrosomal region ; Cytoskeleton ; Ultrastructure ; Immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Monoclonal antibody MN13 raised against mouse spermatozoa specifically recognizes the postacrosomal region of the sperm head in several mammalian species. Colloidal gold-immunoelectron microscopy of demembranated mouse spermatozoa indicated that the antigen is associated with the outer layer of the periodic substructure apparently linking the postacrosomal sheath to the overlying plasma membrane. The antigen recognized by MN13 may cotribute to the intimate association of the postacrosomal sheath with the overlying plasma membrane.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080290312
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  • 52
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    Preparation of spermatogenic cell populations at specific stages of differentiation in the human (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 30 (1991), S. 275-282 
    Details
    ISSN: 1040-452X
    Keywords: Human testis ; Cell separation ; Elutriation ; Spermatid ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Studying biochemical events in human spermatogenesis requires separated populations of spermatogenic cells. Dissociation of these cells was performed by a Trypsin-DNAse method adapted from the technique used for rodents. Cell separation was performed by centrifugal elutriation. Seven populations were collected, one further purified by Percoll gradient centrifugation, giving nine different cell populations. The efficiency of the cell separation was evaluated by phase contrast microscopy, flow cytometric DNA analysis, and electron microscopy. Five populations were enriched in spermatids: two in round spermatids (87% and 73%), another in round (52%) and elongating (44%) spermatids, another constituted by 80% elongating spermatids, and the last by 90% elongated spermatids. Two of the four remaining populations were enrichied in primary spermatocytes (74% and 54%); another population was the upper part of the Percoll gradient and constituted cytoplasmic lobes and residual bodies (89%); the last population was made up of various cells, with no specific enrichment. Electron microscopic observations revealed good preservation of the separated cells; only the flagella from elongated spermatids were lost. Furthermore, an unusual pattern of nucleoplasm distribution during stages 2-4 of spermatid differentiation was observed and its signification is discussed with regard to the shape of the human spermatozoon.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080300316
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  • 53
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    Microfibril-microvessel connections in the rabbit eye: Correlative confocal and electron microscopy (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 74-81 
    Details
    ISSN: 0741-0581
    Keywords: Confocal scanning laser microscopy ; Connective tissue ; Elastic tissue ; Eye ; Microvasculature ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The connections between elastic tissue and microvessels (arterioles, capillaries, and venules) in the rabbit eye were examined by light and electron microscopy. In particular, confocal scanning laser microscopy of tissue stained with orcein and examined by fluorescence using a rhodamine filter was correlated with electron microscopic observations. The goal was an analysis of the way in which elastic tissue of the uvea (i.e., choroid, ciliary body, and iris) and the optic nerve of the eye connect to the microvessels in these structures. Confocal microscopy revealed these connections advantageously and showed how they link the elastic tissue meshwork in the perivascular tissue spaces with the wall of the blood vessels. Electron microscopy showed that the connections consist of bundles of 10-12 nm diameter microfilaments that insert into vascular basement membranes. These connections may contribute to the vascular response to changes in blood pressure or intraocular pressure in the eye.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060180111
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  • 54
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    Sertoli cells and testicular differentiation in the rat fetus (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 172-188 
    Details
    ISSN: 0741-0581
    Keywords: Testis ; Morphogenesis ; Cytodifferentiation ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The fetal testis is not merely a precursor of the adult organ: it is indeed an endocrine gland whose function is the masculinization of the fetus. It differs physiologically and morphologically from the adult testis. In this paper, the first stages of testicular differentiation in the rat are described, with special emphasis on the ultrastructural aspects. At the stage of 13.5 days after fertilization, the first Sertoli cells differentiate; they are characterized by a voluminous and little electron dense cytoplasm, a well-developed RER formed by vesicles and short cisternae filled with a flocculent material. Progressively, they polarize and adhere to one another by adherens-like junctions and cytoplasmic interdigitations to form the differentiating seminiferous cords. In the basal part of the Sertoli cells, a mat of microfilaments differentiates under the plasmalemma, while cytoplasmic blebs protruding in the extracellular space tend to disappear. A continuous basal lamina delineating the seminiferous cords begins to appear on day 14.5 and becomes widespread on day 15.5. These observations, when compared with other data from the literature, emphasize the fact that the differentiation of the Sertoli cells is the first morphological event during testicular differentiation. A possible role of the Sertoli cells in the subsequent organogenesis of the testis is suggested.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060190205
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  • 55
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    Physiology and pathophysiology of the human spermatozoon: The role of electron microscopy (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 17 (1991), S. 412-436 
    Details
    ISSN: 0741-0581
    Keywords: Human sperm ; Ultrastructure ; Pathology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In this article, the major contributions of electron microscopy to the present understanding of the physiology and pathophysiology of the human spermatozoon are reviewed. The ultrastructural organization of sperm organelles playing a significant role for cell function and, therefore, for the reproductive process is described. Also, the major abnormalities and defects of the various organellar systems and how they impair the reproductive function and/or the viability of the cell are reviewed.
    Additional Material: 43 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060170405
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  • 56
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    Cryofixation of vascular endothelium (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 276-290 
    Details
    ISSN: 0741-0581
    Keywords: Cryofixation ; Endothelium ; Blood Vessels ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cryofixation refers to the immobilization of tissue components by the rapid removal of heat from the specimen, so that the structure is interred and stabilized in a natural embedding medium, namely, frozen (amorphous or microcrystalline) tissue water. Cryofixation is now often used as a complement to the more traditional fixation methods, especially when the cell structure is delicate or dynamic and may be inaccurately preserved by the slow selective action of chemical fixatives. Vascular endothelial cells are specialized for transcellular transport and for the regulation of blood flow and composition. The dynamic and labile subcellular organization of these cells, presumably reflecting these functional specializations, makes them ideal candidates for cryofixation.Several different types of endothelial cells were directly frozen at temperatures below 20 degrees Kelvin by pressing them against a liquid-helium-cooled block. These samples were subsequently processed for structural analysis by freeze-substitution. Detailed rationales, designs, and protocols are described for both freezing and freeze-substitution.Electron micrographs of cryofixed arterial and venous capillaries (rete mirabile of the American eel), iliac vein (rabbit), and cultured endothelium from the iliac vein (human) reveal that the organization of the characteristic intracellular membrane system of endothelial vesicles is qualitatively similar to that seen in chemically fixed endothelium, especially with regard to the interconnection of clusters of individual vesicles to form elaborate networks. The luminal and abluminal networks are not in communication, at least not in static images. Quantitatively, however, most directly frozen endothelial cells have far fewer vesicular profiles than comparable glutaraldehydefixed cells. The differences can be explained by presuming that the rapid action of cryofixation (approximately 1 msec) gives a more accurate picture of the vesicular network because it captures the transient structure of labile or dynamic membranes.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060190304
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    Routine cryofixation of plant tissue by propane jet freezing for freeze substitution (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 107-117 
    Details
    ISSN: 0741-0581
    Keywords: Plant ; Leaf ; Root ; Tissue ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cryofixation and freeze substitution methods were developed for ultrastructural studies of cells in complex plant tissues. Leaf tissues and root tips of tobacco (Nicotiana tabacum L. var. Maryland Mammoth) were frozen with a RMC MF7200 propane jet freezer and freeze substituted sequentially with tannic acid and osmium tetroxide/uranyl acetate in acetone. High quality preservation was consistently obtained for epidermal and phloem cells of the leaf, and epidermal, cortical, meristematic, and cap cells of the root tip. Leaf mesophyll cells were also often well frozen. Organelles, including nuclei, endoplasmic reticulum, mitochondria, Golgi bodies, and plastids, showed excellent structural integrity and contrast. Most notable is the superior preservation of the cytoskeleton. Our results demonstrate that the propane jet freezer can be used routinely for high quality cryofixation of higher plant cells in certain complex tissues. This could have important implications for the use of cryofixation approach in a wide range of research in plant biology.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060190111
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  • 58
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    Electronic Resource
    Coquille de l'oeuf de caille: Étude ultrastructurale et cristallographique (1978)
    Springer
    Calcified tissue international 25 (1978), S. 145-159 
    Details
    ISSN: 1432-0827
    Keywords: Bird egg shell ; Ultrastructure ; Calcification ; Electron diffraction ; Microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The egg-shell of Japanese quail was studied by several techniques. Semithin sections (1μm thick) of non-decalcified shell were observed by normal and polarized light microscopy. Thin sections of non-decalcified shell, examined by transmission electron microscopy, permitted us to observe the forms and dimensions of crystals of calcite within different layers of the shell: mammilary layer, layer of cones, palissade layer and surface crystal layer. There appears to be two distinct zones in the layer of cones as well as in the superficial crystal layer. Electron microdiffraction revealed the orientation of calcite crystals in the columns. Some crystal defects (twins?) were described and the possibility of their artefactual formation during ultramicrotomy is discussed. Localization of Ca, Mg, P and S were made by X-ray microanalysis of semithin sections. This technique shows that shell membranes, and chiefly the true cuticle, are also mineralized but, in these layers, minerals are not crystallized. Otherwise the distribution of Mg is not uniform throughout the shell thickness; it is less concentrated in the external zone of the layer of cones. These results together with observation of developing shells by scanning electron microscopy allowed us to propose a scheme for shell organization of the quail egg. This organization was related with decalcification which occurs during hatching.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010763
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  • 59
    Electronic Resource
    Electronic Resource
    The endocrine pancreas in chronic pancreatitis (1978)
    Springer
    Virchows Archiv 377 (1978), S. 157-174 
    Details
    ISSN: 1432-2307
    Keywords: Pancreatic diabetes ; Endocrine pancreas ; Islet composition ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The endocrine pancreatic tissue from patients with severe primary chronic pancreatitis (n=6), secondary chronic pancreatitis due to duct obstruction by carcinoma (n=6) and non-diabetic, non-pancreatitic controls (n=4) was studied qualitatively and quantitatively using specific immunocytochemistry and electron microscopy. Grouping of variously sized islets in the sclerotic tissue (sclerosis islets), islet neoformation by ductuloinsular proliferation, and intrainsular fibrosis were the main qualitative findings. Immunocytochemical quantitation of the distribution of insulin (B), glucagon (A), somatostatin (D) and pancreatic polypeptide (PP) producing cells revealed a significant relative increase in the number of A cells and a decrease in the number of B cells of the sclerosis islets in primary chronic pancreatitis (B-44.1±9.3%:A-38.3±2.4%:D-8.6±5.1%:PP-4.6±4.1%) as well as in secondary chronic pancreatitis (B-38.0±14.3%:A-38.4±19.0%:D-9.1±5.8%:PP-14.5±23.4%) compared with controls (B-71.1±8.1%:A-24.3±5.5%:D-8.0±2.8%:PP-0.5±0.4%). The number of PP cells was significantly increased in primary chronic pancreatitis only. It is suggested that scarring of the exocrine pancreas affects islet composition, probably by impairment of the local circulation and of glucose diffusion, thus leading to reduction of the number and glucose sensitivity of B cells. The hyperplasia of A and PP cells appears to be a secondary phenomenon due to the loss of B cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00427003
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  • 60
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    Ultrastructure and morphometry of ACTH-producing cell in the rat anterior pituitary gland stimulated by lysin-vasopressin and prostaglandin E1 (1978)
    Springer
    Virchows Archiv 378 (1978), S. 23-33 
    Details
    ISSN: 1432-2307
    Keywords: Pitutary ; Ultrastructure ; Vasopressin ; Prostaglandin ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ziel dieser Untersuchung war es, quantitative and qualitative Änderungen der ACTH-Zelle in der Rattenhypophyse nach Gabe eines spezifischen und eines unspezifischen Stimulus zu untersuchen. Es wurden ein CRF-Analogon (Lysin-Vasopressin) und ein Prostaglandin (Prostaglandin E1) benutzt. Jeweils 20 Ratten wurden für 4 Wochen Lysin-Vasopressin oder Prostaglandin E1 intraperitoneal injiziert. Die Hypophysen wurden licht- und elektronenoptisch sowie morphometrisch untersucht. Nach Gabe beider Stoffe konnte man eine Aktivierung der ACTH-Zellen beobachten. Die Vergrö\erung des Kerns, des Cytoplasmas und der an der Hormonherstellung beteiligten Zellorganellen lie\ sich morphometrisch nachweisen, wobei die Wirkung von Lysin-Vasopressin ausgeprÄgter war als die des Prostaglandins. Darüber hinaus konnte eine Zunahme der ACTH-Zellzahl gefunden und mit einem statistischen Test als signifikant nachgewiesen werden. Im Gegensatz zu Lysin-Vasopressin erstreckte sich die Wirkung des Prostaglandins auch auf andere Hypophysenzellen.
    Notes: Summary The aim of this study was to investigate the qualitative and quantitative changes of ACTH-cells in the rat after application of a specific and a non-specific stimulus. A CRF-analog (lysin-vasopressin) and a prostaglandin (prostaglandin E1) were used. 40 rats were injected lysin-vasopressin or prostaglandin E1, respectively, for 4 weeks. The pituitary glands were investigated by means of light microscopy, electron microscopy and morphometry. Activation of the ACTH-cells could be observed after use of both substances, the effect of lysin-vasopressin being more intense than that of prostaglandin E1. Enlargement of the nucleus, the cytoplasm and the organelles involved in hormone-production and -transport were found and verified by morphometry. Additionally an increase in number of the cells could be demonstrated. Prostaglandin influenced not only ACTH-cells, but also other cells of the anterior pituitary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00427183
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  • 61
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    An ultrastructural study of the placenta in materno-fetal rhesus incompatibility (1978)
    Springer
    Virchows Archiv 379 (1978), S. 229-241 
    Details
    ISSN: 1432-2307
    Keywords: Placenta ; Ultrastructure ; Rhesus incompatibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An electronoptical study has been made of eleven placentae from cases of materno-fetal rhesus incompatibility. The characteristic findings are focal, but sometimes quite extensive, syncytial necrosis, retention of normal pinocytotic and secretory activity in the non-necrotic syncytiotrophoblast, cytotrophoblastic hyperplasia, thickening of the trophoblastic basement membrane, immature-type endothelial cells in the fetal villous vessels and thickening or lamination of the capillary basement membranes. The pathogenesis of many of these changes is not clear but there is no evidence that they are immunologically mediated. It is suggested that the syncytial necrosis may be due to narrowing of the intervillous space as a result of increased villous size, that the cytotrophoblastic hyperplasia is a response to the syncytial damage and is responsible for the changes in the trophoblastic basement membrane and that the fetal capillary changes are indicative of endothelial cell damage due, possibly, to fetal anaemia. Despite the damage suffered by the placenta in materno-fetal rhesus incompatibility there is little evidence of impaired functional efficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00432638
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  • 62
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    Chemodectoma of the larynx (1978)
    Springer
    Virchows Archiv 378 (1978), S. 161-172 
    Details
    ISSN: 1432-2307
    Keywords: Chemodectoma ; Larynx ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present case report is concerned with a clinico-pathological study, including ultrastructural investigation, of a rare and uncommon laryngeal tumour, a chemodectoma, in a 62 year old patient. There have been 23 cases of laryngeal chemodectomas reported in the literature, and only three of them, including our own report, were investigated by electron microscopy. The tumours arise from the superior and inferior laryngeal nonchromaffin paraganglia or possibly from Kultschitzky-cells of the normal bronchial mucosa. Ultrastructurally they have all the characteristics of apudomas whose parent cells (the APUD-cells), usually show endocrine function and probably have their origin in the neural crest. The tumours show an aggressive type of behaviour, despite usually benign histological features when compared to chemodectomas at other sites in the head and neck region. Surgery is thus the therapy of choice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00432360
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  • 63
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    Electronic Resource
    Giant cell tumor of bone (1978)
    Springer
    Virchows Archiv 378 (1978), S. 287-295 
    Details
    ISSN: 1432-2307
    Keywords: Giant cell tumor ; Ultrastructure ; Alkaline phosphatase ; Human bone neoplasias
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structural localization of nonspecific alkaline phosphatase was elucidated in two giant cell tumors of bone using lead as capturing ion and Β-glycerophosphate as substrate in the incubation solution. Lead phosphate precipitate — indicating presence of alkaline phosphatase — was demonstrated on the plasma membranes, and the membranes bordering vesicles and vacuoles of presumed endocytotic nature, in giant cells and type 1 stromal cells (fibroblast-like cells). The findings support the view that stromal cells type I and giant cells are histogenetically related.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00465595
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  • 64
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    The ultrastructure of bone cells and bone matrix in human primary hyperparathyroidism (1978)
    Springer
    Virchows Archiv 379 (1978), S. 11-23 
    Details
    ISSN: 1432-2307
    Keywords: Primary hyperparathyroidism ; Bone cells ; Bone matrix ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An electron microscope investigation has been carried out on needle biopsies of the iliac crest of 8 patients suffering from primary hyperparathyroidism. A marked increase in bone resorption was the most conspicuous finding. It was due both to increased osteoclastic activity and to periosteocytic osteolysis. The osteoclasts had a more strongly developed brush border and contained more cytoplasmic vacuoles than those in controls. Many osteocytes were found within enlarged, irregular lacunae, and were surrounded by a space containing amorphous, granular and filamentous material. Their mitochondria were sometimes calcified. Osteoblasts were more active than in controls as shown by the developed rough ergastoplasmic cysternae and thick osteoid borders found near some of them. The osteoid tissue, however, was uncalcified; ultrastructurally, lack of the calcification front and incomplete matrix calcification were demonstrable. Mast cells, and osteoclast- and macrophage-like giant cells were often found in the fibrotic marrow spaces. These results confirm that both the resorption and the formation of bone are stimulated in hyperparathyroidism. The calcification process is delayed and often remains incomplete.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00432779
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  • 65
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    Malignant giant cell tumor of bone (1978)
    Springer
    Virchows Archiv 379 (1978), S. 185-201 
    Details
    ISSN: 1432-2307
    Keywords: Giant cell tumor ; Ultrastructure ; Acid phosphatase ; Lysosomes ; Bone tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of the different cell types constituting a primary malignant giant cell tumor of bone has been studied and the localization of acid phosphatase in relation to the subcellular organelles been demonstrated. Three distinct cell types with characteristic ultrastructural features were observed: giant cells, fibroblast-like cells, and cells with abundant lipid inclusions and mitochondria. Certain differences were noted between these three cell types and their counterparts in benign giant cell tumors of bone (described in a separate report). The enzyme histochemical and morphological data suggested that the giant cells in the malignant tumor might possess a more active and expansive lysosomal apparatus than corresponding cells in the benign variant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00432635
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  • 66
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    Pinguecula et pterygion: étude histopathologique et ultrastructurale (1978)
    Springer
    Virchows Archiv 379 (1978), S. 321-333 
    Details
    ISSN: 1432-2307
    Keywords: Pinguecula ; Pterygium ; Histology ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two pingueculae combined with pterygia were studied by light and electron microscopy. Hyaline degeneration of the collagen, dark staining granular, von Kossa negative concretions and elastotic material were observed in both conditions together with marked changes in the fibroblasts, endothelial cells, pericytes and the basement membrane of conjunctival capillaries and small veins. The elastotic material is similar to that observed in solar elastosis, where the collagen fibers are less severely damaged. Chronic sun exposure of the pericorneal conjunctiva may damage endothelial cells primarily and disturb vascular exchanges. This would result in accelerated degeneration and regeneration of endothelial cells, in thickening of the basement membrane and, secondarily, disturbed metabolism of fibroblasts with alterations of the collagen and elastic fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464475
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  • 67
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    Ribosome-submembranous density complex (1978)
    Springer
    Acta neuropathologica 44 (1978), S. 249-250 
    Details
    ISSN: 1432-0533
    Keywords: Organelle complex ; Ribosomes ; Meningioma (malignant) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural study of a malignant meningioma revealed an organelle complex composed of: (1) A band-like densification of the cell cytoplasm adjacent to and in contact with the cell membrane. (2) An arciform filament immediately subjacent to it, with concavity directed away from the cell membrane. (3) A row of regularly spaced ribosomes located in the concavity, but at some distance from the arciform filament. (4) A pericellular condensation of interstitial ground substance. Occasionally, a second, thinner filament was seen “threading” the ribosomes together. Its morphology was consistent with that described for messenger RNA. It is suggested that the ribosomes are engaged in the synthesis of proteins for other portions of the organelle complex and that the ultimate role of the specialized unit would be that of an attachment device.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691076
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  • 68
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    Studies on the liver of Xenopus laevis (1978)
    Springer
    Anatomy and embryology 154 (1978), S. 1-25 
    Details
    ISSN: 1432-0568
    Keywords: Bile canaliculus ; Development ; Glycogenesis ; Hepatocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural changes during development and metamorphosis in the liver ofXenopus laevis have been investigated. In this species it was found that developmental processes, which ultimately lead to the formation of bile canaliculi, can be detected in the liver anlage as early as stage 35. While the wall of the primary liver cavity is thrown into folds which form the liver parenchyma, the bile canaliculi are formed (st. 36–38). Secretion into the lumen of the bile canaliculi was not found to occur before stage 47 and IDP-ase activity could not be detected in the bile canaliculi before stage 49. The intra- and extrahepatic portions of the hepatic duct system were found to be formed during the stages 40–41. The formation of the duct system involves cellular degeneration in the lumen of the future ducts. These processes are described in detail. The glycogen content of the developing hepatocytes received particular attention during the course of this study. It was found that after depletion of the embryonal glycogen the hepatocytes are completely free from glycogen during the stages 43–45. At stage 46, after the begin of feeding, beta as well as alpha particles of glycogen appear in the hepatocytes. These first reappearing glycogen particles are formed without the participation of SER membranes, in areas which are loaded with RNA particles. It was found that only after the synthesis of glycogen had been initiated SER membranes started to proliferate in the hepatocytes, where they were mostly found intermingled with glycogen particles. From stage 54 on, where the liver glycogen content was found to be 0.2%, the glycogen content of the liver almost continuously increased until it reached a temporary peak of 10% at the end of metamorphosis. These findings strongly contrast results reported for other amphibia, which at the end of metamorphosis have depleted their glycogen content completely. Details of the ultrastructural changes occuring during development of the hepatocytes, are also reported in this paper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317951
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    The ependymal and glial configuration in the spinal cord of urodeles (1978)
    Springer
    Anatomy and embryology 154 (1978), S. 67-82 
    Details
    ISSN: 1432-0568
    Keywords: Urodeles ; Spinal cord ; Ependyma ; Glia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The structural organization of the ependymal and macroglial components of the central field of the spinal cord of postmetamorphic ribbed newts has been reinvestigated using elaborate fixation procedures for transmission electron microscopy. All along the central canal, the ependymal cells display ultrastructural features that strongly suggest a secretory activity. Infrequent mitotic images, occurring spontaneously among the ependymal cells, were observed. The tightly compacted periependymal stratum contains two types of glial cells: 1. oligodendrocytes, also observed outside this stratum as neuronal satellites, and 2. radial astrocytic cells, whose somata, exclusively located in the periependymal stratum, send their processes to the subpial lamina. The intercellular relationships between ependyma, oligodendrocytes and astrocytic cells are illustrated to show the continuity of the neuroepithelial configuration. Morphologic clues for identifying the cells of the central field of the urodele spinal cord are given. A gradient of differentiation of the oligodendroglial components could be postulated. In normal conditions, the astroglial differentiation is permanently arrested at the stage of radial glia. Some considerations concerning regeneration in the urodele spinal cord are submitted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317955
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  • 70
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    Electronic Resource
    Ultrastructural study of the adenohypophysis of the male Chinese quail (1978)
    Springer
    Anatomy and embryology 154 (1978), S. 185-211 
    Details
    ISSN: 1432-0568
    Keywords: Adenohypophysis ; Cellular types ; Ultrastructure ; Birds ; Excalfactoria chinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural analysis of the adenohypophysis in the male Chinese quail reveals seven different types of granular cells, and agranular folliculo-stellate cells. The cell types are assumed to be endocrine cells and are classified as: Type I cells (presumptive LH-gonadotrophs), with dilated endoplasmic reticulum, perinuclear spaces, and granules of 150–260 nm; Type II cells (presumptive FSH-gonadotrophs), with regularly-shaped cytoplasmic cisterns and small granules (80–150 nm); Type III cells (presumptive thyrotrophs), very close in appearance to the type II cells of normal birds; Type IV cells (presumptive prolactin cells), with very large secretory granules (up to 400 nm), Type V cells (presumptive corticotrophs), with abundant and electrondense granules (160–300 nm); Type VI cells, with irregularly-shaped granules; Type VII cells (presumptive somatotrophs), with abundant granules (130–220 nm) and less cytoplasmic structures. Cytological characteristics of the nucleus, and more particularly the presence of a Feulgen-positive nucleolus with a very particular ultrastructure are here reported. It is proposed that heterospecific associations of Chinese quail cells with chick cells can be used in embryological work for the study of cellular interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00304662
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    Electronic Resource
    Collagen metabolism in granulating wounds of rat skin (1978)
    Springer
    Archives of dermatological research 263 (1978), S. 207-214 
    Details
    ISSN: 1432-069X
    Keywords: Wound healing ; Collagen metabolism ; Collagen degradation ; Fibroblasts ; Ultrastructure ; Wundheilung ; Kollagenstoffwechsel ; Kollagenabbau ; Fibroblasten ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der Kollagenstoffwechsel in granulierenden Hautwunden der Ratte wurde mittels biochemischer, tracerkinetischer und elektronenmikroskopischer Methoden untersucht. Die Ablagerung von Kollagen in Hautwunden der Ratte war nicht nur das Ergebnis eines Anstiegs der Kollagensynthese, sondern wurde ebenso durch eine Abnahme des Kollagenabbaus bedingt. Unsere Ergebnisse zeigten signifikante Unterschiede im Kollagenumsatz zu verschiedenen Zeiten der Wundheilung. Der herabgesetzte Kollagenkatabolismus in den frühen Stadien der Wundheilung steuerte in entscheidender Weise zur Kollagenakkumulation im Wundgebiet bei. Während späterer Stadien, zum Zeitpunkt der Wundkontraktion und der Remodellierung der Narbe, stieg die Umsatzrate des Kollagens an. Die dargestellten Ergebnisse werden im Zusammenhang mit den allgemeinen Kriterien der Narbenbildung diskutiert.
    Notes: Summary Collagen metabolism in granulating wounds of rat skin was studied with biochemical, isotopic and electron microscopical methods. Deposition of collagen in rat skin wounds was not only the result of an increase in collagen synthesis but it was also caused by a decrease in collagen degradation. Our investigations showed significant differences in the collagen turnover at different times of wound healing. Decreased collagen catabolism at the early stages of wound healing contributed decisively to collagen accumulation in the wound area. At later stages, during wound contraction and remodelling of the scar, the rate of collagen degradation rose. The above-mentioned results are discussed in the context of general criteria of scar formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00446442
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  • 72
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    Elektronenmikroskopische Untersuchung am cutanen Leiomyosarkom (1978)
    Springer
    Archives of dermatological research 263 (1978), S. 159-169 
    Details
    ISSN: 1432-069X
    Keywords: Leiomyosarcoma of the skin ; Ultrastructure ; Cellular differentiation ; Accumulation of centrioles ; Cutanes Leiomyosarkom ; Ultrastruktur ; celluläre Differenzierung ; multiple Centriolen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine 61jährige Patientin hatte sich vor 15 Jahren einen Tumor vom linken Unterschenkel entfernen lassen. Im Bereich der Narbe kam es zu erneuter Tumorbildung. Die histologische Untersuchung zeigte einen aus meist spindeligen Zellen zusammengesetzten Tumor mit vielen Mitosen und Kernpolymorphie. Die Diagnose eines cutanen Leiomyosarkoms wurde durch den elektronenmikroskopischen Nachweis der für glatte Muskelzellen charakteristischen Zellelemente gesichert. Der Differenzierungsgrad der Tumorzellen variierte zwischen relativ differenzierten, filamentreichen Zellen, die noch an normale glatte Muskelzellen erinnerten, und ödematösen, filamentarmen, aber organellenreichen entdifferenzierten Zellen. Eine auffallende morphologische Besonderheit war der wiederholte Nachweis von zahlreichen akkumulierten Centriolen.
    Notes: Summary A 61-year old woman developed a tumourous nodule in her left leg. Fifteen years ago a similar tumour had been removed in the same localization. Histological examination performed on biopsy material showed bundles of predominantly fusiform tumour cells with nuclear pleomorphism and many mitotic figures. Electron microscopic examination confirmed the diagnosis of leiomyosarcoma by demonstration of the ultrastructural characteristics of smooth muscle cells. Cellular differentiation showed various degree ranging from smooth muscle cell type to dedifferentiated edematous tumour cells with scanty myofilaments. An important finding was the demonstration of multiple accumulated centrioles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00446437
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    Vergleichende Untersuchungen bei juvenilem und adultem Colloid Milium (1978)
    Springer
    Archives of dermatological research 261 (1978), S. 231-244 
    Details
    ISSN: 1432-069X
    Keywords: Colloid Milium ; Different types ; Histopathology ; Ultrastructure ; Colloid Milium ; Verschiedene Typen ; Histopathologie ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Unterschiede im Verlauf und Erbmuster des Colloid Milium deuten an, daß zwischen dem juvenilen und adulten Typ dieser Dermatose wesentliche Unterschiede bestehen. Ziel der vorliegenden Untersuchungen war, mit Hilfe von Licht-, Immunfluorescenz- und elektronenoptischen Methoden nach Unterschieden im mikroskopischen Bereich anhand je eines Falles zu suchen. Folgende Befunde wurden erhoben: Beim juvenilen Colloid Milium sind die Kolloidmassen nicht nur direkt unter dem Epithel abgelagert, sondern auch innerhalb der Epidermis häufig zu finden. Sie zeigen nach Kongorotfärbung einen Dichroismus und können Immunglobuline, Komplement und Fibrin enthalten. Elektronenmikroskopisch zeigt sich, daß sie aus dicht gepackten wellig verlaufenden Fibrillen bestehen, deren individueller Durchmesser etwa 80 Å beträgt. Innerhalb dieser fibrillären Massen sind häufig Melanosomen, Reste von Kernen und anderen Zellorganellen sowie Desmosomen nachweisbar. Beim adulten Colloid Milium sind die Kolloidmassen meist von der Epidermis durch einen Elastika-positiven Bindegewebsstreifen getrennt. Mit Kongorot sind sie nur schwach darstellbar und zeigen keinen Dichroismus. Fluorescenzoptisch zeigen sie eine bläuliche Autofluorescenz, aber keine spezifischen Ablagerungen. Elektronenmikroskopisch kann das adulte Kolloid als feingranuläres Material mit wenigen feinsten Mikrofibrillen charakterisiert werden, das in enger Nachbarschaft von Gefäßen mit verdichteter Basalmembran und von aktiven Fibroblasten gelegen ist. Auf Grund dieser Unterschiede können der juvenile und adulte Typ des Colloid Miliums klar auch mikroskopisch voneinander differenziert werden. Die Ergebnisse deuten darauf hin, daß beim juvenilen Typ vorwiegend epidermale Läsionen, beim adulten jedoch dermale Störungen eine wesentliche Rolle in der Pathogenese spielen.
    Notes: Summary Two different types of colloid milium are characterized on the basis of clinical and genetical parameters. In order to establish morphological criteria allowing a differentiation also at microscopic levels comparative histopathological, histo- and immunochemical as well as ultrastructural investigations were performed in a case of juvenile and a case of adult colloid milium. The following results were obtained: In juvenile colloid milium the colloid material is deposed in direct apposition to the basal epidermal layers and can be found also in suprabasal position within the epidermis. No actinic elastosis is present in the periphery of the deposits but they exhibit a green birefringency by investigation of Congo-red stained frozen sections in polarized light. Immunoglobulins, complement and fibrin can be demonstrated within the deposits by direct immunofluorescence. Electron microscopy reveales a fibrillar ultrastructure of the colloid masses, which contain numerous melanin granules and desmosomes. Therefore the colloid material in the juvenile type is most likely of epidermal origin. In adult colloid milium the colloid is usually separated from the epidermis by a band of connective tissue elements containing a considerable amount of elastin. The surrounding superficial dermis frequently exhibits elastotic changes. Congo-red reaction is only weakly positive and no dichroisms can be found. Direct immunofluorescence reveals no specific staining, but a blue autofluorescence of the material. Ultrastructurally, the adult colloid represents mainly finely granular material, with only few microfilaments. The masses are situated in the dermis, often near duplicated vascular basement membranes and in close apposition to active fibroblasts. Thus, the colloid material seems to be of dermal origin. The microscopic findings strongly indicate, that the two different types of colloid milium indeed represent different entities, discernable not only by clinical or genetic but also by histomorphologic parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455291
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  • 74
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    Action of the “nude” gene on pigmentation of the coat in C57 black and C3H mice (1978)
    Springer
    Archives of dermatological research 262 (1978), S. 219-227 
    Details
    ISSN: 1432-069X
    Keywords: Nude mice ; Skin pigmentation ; Ultrastructure ; Tyrosinase activity ; Hair cycle ; Nackte Mäuse ; Hautpigmentierung ; Ultrastruktur ; Tyrosinaseaktivität ; Haarcyclus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Autoren untersuchten die Pigmentveränderungen an Haut und Haar an pigmentierten nackten Mäusen. Histologische und elektronenmikroskopische Untersuchungen und die Polyacrylamid-Elektrophorese der Tyrosinaseaktivitäten zeigten vom morphologischen und biochemischen, daß die Veränderungen der Programmierung solcher “nude” Mäuse auf den Haarcyclus und auf das Haarwachstum bezogen werden kann. In der Tat entwickeln sich die Haarfollikel cyclisch wie die der Mäuse mit normaler Haut. In depigmentierter Haut waren die Haare in der Ruhepause und es konnte keine lösliche Tyrosinase aufgefunden werden.
    Notes: Summary The authors have studied pigmentary changes of skin and hair due to the presence of the “nude” gene in pigmented species (C 57 Bl. 6J, C 3H). Morphological (histology, electron microscopy) and biochemical (polyacrylamide gel electrophoresis of tyrosinase activities) studies showed that the pigmentary alterations of the “nude” mice were related to the hair cycle and hair growth wave pattern. In fact, in the “nude” mice the hair follicles evolves cyclically similarly to mice of normal coat. In depigmented skin, the hair follicles were in the resting phase and no soluble tyrosinase could be demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455393
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  • 75
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    Electronic Resource
    Pseudolymphoma of skin induced by oriental hornet (Vespa orientalis) venom (1978)
    Springer
    Archives of dermatological research 262 (1978), S. 135-141 
    Details
    ISSN: 1432-069X
    Keywords: Pseudolymphoma ; Oriental hornet venom ; Ultrastructure ; Pseudolymphoma ; Orientalische Wespe ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine einmalige sucutane Injektion des Giftes der orientalischen Wespe führt bei schwarzen Mäusen zu der Entwicklung eines subcutanen Knötchens, welches sich über 1 Jahr hält. Ultrastrukturell zeigt sich eine Anreicherung von Lymphocyten und Lymphoblasten und einige Plasmazellen mit Russelkörperchen. Zusätzlich werden einige Melanin enthaltende Makrophagen und auch solche mit aufgenommenen cellulären Abbauprodukten beobachtet. Die gesamte Reaktion wird mit anderen pseudolymphomatösen Reaktionen in der Haut in Beziehung gesetzt.
    Notes: Summary A single subcutaneous injection of Oriental hornet venom into black mice led to the development of a subcutaneous nodule which showed no change during the period of 1 year. Study of the ultrastructure revealed an accumulation of lymphocytes and lymphoblasts and a few plasma cells with formation of Russel bodies. In addition, a few melanin-containing macrophages and macrophages filled with cellular debris were found. This reaction is compared to other pseudolymphomatous reactions in the dermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455382
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  • 76
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    Electronic Resource
    The ultrastructure of mycobacterium marinum granuloma in man (1978)
    Springer
    Archives of dermatological research 262 (1978), S. 205-217 
    Details
    ISSN: 1432-069X
    Keywords: Mycobacterium marinum ; Ultrastructure ; High-turnover granuloma ; Immunogenic orgin ; Intracellular collagen precursor ; Mycobaterium marinum ; Ultrastruktur ; High-turnover Granulom ; Immunogenes Granulom ; Intracelluläre Kollagenpräcursoren
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Drei Knoten (klinisches Alter 3–5 Wochen) von 2 Patienten mit sogenannten Swimmingpool- oder Aquariumgranulomen wurden elektronenoptisch untersucht. Das cytohistologische Spektrum umfaßt sowohl akute exsudative, als auch chronische proliferative Entzündungszeichen. Bereits im 3 Wochen alten Granulom sind Epitheloidzellen und Kollagen produzierende Fibroblasten nachweisbar. Das Mycobacterium marinum-Granulom stellt gemäß dem cytologischen Aufbau ein sog. High-turnover Granulom mit allergischer Genese dar. Es entspricht damit mycobacteriellen Dermatosen bei bestehender guter Abwehrlage (Lupus vulgaris, tuberkuloide Lepra). In Abbau befindliche Mycobacterien konnten in wenigen Phagocyten entdeckt werden. Die Ultrastruktur des lebenden Erregers wird vergleichsweise von tierexperimentellem Material präsentiert. Geschwungene und ringförmige parallele Membranen (“Worm-like structures”) wurden im Cytoplasma von transformierten Makrophagen und in Fibroblasten beobachtet. Fadenförmige quergebänderte Strukturen (Periodizität 170–180 Å) im Lumen des rauhen endoplasmatischen Reticulums von einigen Fibroblasten werden als intracellulär aggregierte Kollagenpräcursoren interpretiert.
    Notes: Summary 3 biopsies of 3–5 week-old nodular lesions in 2 patients with socalled swimming-pool (aquarium-) granuloma have been examined by electron microscopy. The cytohistological spectrum simultaneously comprises acute exudative as well as chronic proliferative phenomena. Epithelioid cells and collagen producing fibroblasts already conspicious in 3 week-old granuloma. According to the cytological composition the Mycobacterium marinum granuloma represents a high-turnover granuloma with immunogenic origin. It is comparable to mycobacterial diseases in the presence of well developed cell mediated immunity (Lupus vulgaris, tuberculoid leprosy). Degrading mycobacteria have been rarely detected in phagocytes and are compared with viable bacilli in macrophages of experimentally infected mice. Curved and annular parallel membranes (“worm-like structures”) in the cytoplasm of transformed macrophages and in fibroblasts presumably originate from the membranes of endoplasmic reticulum. Cord-like structures with transverse bands (periodicity 170–180 Å) in the lumen of RER of some fibroblasts are interpreted as intracellularly aggregated collagen precursors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455392
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  • 77
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    Electronic Resource
    Ultrastructural detection of Haemophilus ducreyi in biopsies of chancroid (1978)
    Springer
    Archives of dermatological research 263 (1978), S. 153-157 
    Details
    ISSN: 1432-069X
    Keywords: Chancroids ; Biopsies ; Haemophilus ducreyi ; Ultrastructure ; Ulcera mollia ; Biopsien ; Haemophilus ducreyi ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Anläßlich einer lokalen Häufung von insgesamt 26 Ulcus molle-Fällen in Berlin (West) wurden in Biopsien coccoide Stäbchen durch ultrastrukturelle Untersuchung entdeckt. Ihre Zellwand ist ca. 120 Å dick und trilaminar entsprechend Gram-negativen Bakterien. Die Bakterien sind hinsichtlich der Zellwandstruktur sowie der Cytoplasmazusammensetzung identisch mit Haemophilus ducreyi, die kulturell von typischen Ulcera mollia gezüchtet, intermittierend mikroskopisch auf Reinheit geprüft, in tierisches Material geimpft und anschließend ultrastrukturell untersucht wurden. In menschlichem ulcerösen Gewebe finden sich die Bakterien überwiegend im Extracellulärraum und in Gruppen gelagert.
    Notes: Summary During an endemic appearance of chancroids (26 cases) in Berlin (West) coccobacilli were disclosed in biopsies by electron microscopy. The bacteria were aggregated predominantly in groups in the extracellular space. Their cell wall is approximately 120 Å thick and trilaminar as in Gram-negative bacteria. Concerning the cell wall structure and the cytoplasmic composition, the detected coccobacilli are identical to culturally grown Haemophilus ducreyi obtained from chancroids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00446436
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  • 78
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    Étude en microscopie électronique et par cytophotométrie à balayage de la structure et de la distribution de la chromatine dans les noyaux des cellules cartilagineuses deTriturus cristatus âgés au cours de la régénération (1978)
    Springer
    Development genes and evolution 184 (1978), S. 195-211 
    Details
    ISSN: 1432-041X
    Keywords: Ultrastructure ; Scanning cytophotometry ; Chromatin ; Chondrocytes ; Regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les cellules cartilagineuses des membres postérieurs deTriturus cristatus en régénération après amputation, ont été étudiées en microscopie électronique et par cytophotométrie à balayage. Nous nous sommes intéressés à la structure et à la distribution de la chromatine mais aussi à différents organites cytoplasmiques. Dans l'étude de cytophotométrie à balayage, la chromatine a été considérée à travers son constituant majeur, l'ADN, coloré par la réaction de Feulgen. Au cours de la régénération du membre, l'hétérochromatine initialement condensée, essentiellement accolée à la membrane nucléaire se décondense. Les vacuoles du cytoplasme, caractéristiques des animaux âgés par rapport aux animaux jeunes, disparaissent, les mitochondries et le reticulum endoplasmique rugueux deviennent plus abondants. Les caractéristiques nucléaires de l'activation cellulaire apparaissent précocement, précédent les modifications cytoplasmiques et conduisent à des cellules en tous points identiques aux cellules d'animaux jeunes en dehors de tout processus régénératif. Cette phase d'euchromatisation et de restructuration cytoplasmique est peut-être nécessaire à l'accroissement d'activité métabolique et à la division cellulaire qui suivent. Son déroulement peut expliquer tout au moins le ralentissement de la régénération observé chez les animaux âgés par rapport aux animaux jeunes.
    Notes: Summary Cartilaginous cells of aged newts (Triturus cristatus) were studied during hind limb regeneration. The electron microscope was used to study the structure and distribution of chromatin in the cell nuclei, while the DNA content of the chromatin was measured by means of a scanning cytophotometer. Changes in the ultrastructure of the cytoplasm during regeneration were also studied. It was observed that the structure and distribution of chromatin in the activated cell is greatly modified. In the non-activated cell of the aged newt, the chromatin is found highly condensed and distributed peripherally close to the nuclear membrane. In contrast, in the activated cells, the chromatin is much less condensed and is distributed throughout the nucleus. Moreover, cytoplasmic vacuoles, found only in the non-activated aged cells, disappear and an increase in the mitochondria and rough endoplasmic reticulum is also observed. Changes in the nuclear structure are observed prior to the cytoplasmic modifications. It is interesting to note that the process of activation induces structural changes in the aged cells which make these cells appear to be structurally identical to the young cells. This process of rejuvenation takes 3–5 days in the newt. We suggest that these structural changes of the chromatin and cytoplasm in the aged cells are necessary to increase the metabolic activity which precedes cell division. It may also explain why regeneration takes a longer time in the aged animals than in the young ones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848254
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  • 79
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    Nemaline myopathy: Histological, histochemical and ultrastructural studies (1978)
    Springer
    Acta neuropathologica 42 (1978), S. 33-41 
    Details
    ISSN: 1432-0533
    Keywords: Nemaline myopathy ; Neuromuscular junction ; Myotendinous junction-like structure ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Histological, histochemical and ultrastructural studies were performed on muscle biopsies from three siblings with congenital nemaline myopathy. Histological studies revealed type I fibre atrophy and type II fibre paucity. Ultrastructural studies of intramuscular nerves showed that the axonal diameters were very narrow compared with the width of myelin lamellae. Granular or membranous osmiophilic material occurred in the adaxonal Schwann cell cytoplasm and had a periodicity of 33–38Å. The neuromuscular junctions showed degenerative features such as glycogen granules or myelin figures in 27.1% of total terminal axons. The secondary synaptic clefts were markedly decreased in number and short in length. Myotendinous junction-like structures were found in 5.5% of the muscle fibres near the neuromuscular junctions, and often near sites of fibre-splitting. Rods in nemaline myopathy might be caused as a result of longitudinal splitting and disruption of fibres due to deficient regeneration of the muscle fibres associated with neurotrophic abnormalities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01273264
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  • 80
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    Electronic Resource
    Choroid plexus papilloma: Light and electron microscopic study of three cases (1978)
    Springer
    Acta neuropathologica 44 (1978), S. 235-239 
    Details
    ISSN: 1432-0533
    Keywords: Choroid plexus papilloma ; Ultrastructure ; Cytoplasmic ; Inclusions ; Silver bodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three cases of choroid plexus papilloma were studied by light and electron microscopy. All had the typical papillary pattern, and, in addition, two exhibited solid areas of tumor growth which predominated in one case. PAS positive (diastase resistant) and argyrophilic cytoplasmic inclusions were present in all three tumors but were particularly abundant in the predominantly solid one. Ultrastructurally, the inclusions appeared as irregularly shaped structures containing lipid droplets, filamentous material and microtubules, and resembled the “silver bodies” of Biondi found in normal choroid plexus. Along with other ultrastructural features of normal choroid plexus, these cytoplasmic inclusions may be helpful in the differential diagnosis of papillary tumors involving the ventricular system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691073
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  • 81
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    Electronic Resource
    Ultrastructure of oncocytic adenoma of the human pituitary gland (1978)
    Springer
    Acta neuropathologica 41 (1978), S. 169-171 
    Details
    ISSN: 1432-0533
    Keywords: Pituitary gland ; Oncocytic adenoma ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two cases of oncocytic adenoma occurring in the pituitary are reported. Both were men aged 40 and 50 years respectively and there was no evidence of endocrine abnormality. In both the tumours many cells showed abundant acidophilic finely granular cytoplasm which had not stained positively with PAS-orange G stain. Electron microscopically the cells contained numerous mitochondria associated with marked reduction of other cytoplasmic organelles including the secretory granules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689770
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  • 82
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    Electronic Resource
    Myélinopathie par intoxication oxycarbonée. Neuropathologie ultrasturale (1978)
    Springer
    Acta neuropathologica 43 (1978), S. 153-159 
    Details
    ISSN: 1432-0533
    Keywords: Myelin ; Oligodendroglia ; Human pathology ; Ultrastructure ; Carbon monoxyde ; Anoxia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 24-year-old woman was found comatose after 2 days of cephalalgia and vomiting. An immediate diagnosis of carbon monoxyde poisoning was disclaimed when blood carbon monoxyde was found to be 1.75 ml/100. A diagnosis of acute intracranial hypertension led to trephination with ventricular punction and brain biopsy on the third day. The patient died on the eleventh day. Ultrastructural study of biopsy tissue showed nearly normal cortex, and injured white matter, with disrupted or destroyed myelin and pycnotic oligodendroglia in contrast with nearly normal axons, astrocytes, and capillaries. Autopsy showed a typical semioval center myelinopathy. After discussion of the histotoxic, vascular, and edema theories for myelinopathy pathogenesis, primary oligodendrogial lesion is considered, and correlated with the diphasic evolution often observed in the course of carbon monoxyde myelinopathy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685010
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  • 83
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    Electronic Resource
    Morphological, biochemical, ultrastructural, tissue culture and clinical observations of typical and aggressive craniopharyngiomas (1978)
    Springer
    Acta neuropathologica 43 (1978), S. 191-203 
    Details
    ISSN: 1432-0533
    Keywords: Cultured ; Craniopharyngioma ; Typical ; Atypical ; Ultrastructure ; Electron microscopy ; Biochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Craniopharyngiomas are tumors of the suprasellar area, which are often cystic, encapsulated and slow-growing. Certain of these tumors can behave in an aggressive manner and either invade surrounding structures or recur. In order to determine characteristics which may aid in distinguishing typical from atypical lesions, a study of biopsy and tissue culture specimens from 25 human craniopharyngiomas was undertaken. Tissue culture observations reveal two distinct cell populations. Typical lesions grew in culture in an orderly epithelial pattern and had desmosome-tonofibril aggregates and smooth surface topography demonstrable by electron microscopy. In the atypical tumors the cell growth was irregular, with mitotic activity, cholesterol crystals and features characteristic of neoplastic transformation, such as surface microvilli, an increase of cytoplasmic basophilia, size and number of nucleoli and retraction of cytoplasm. Correlation with the clinical status of the patients suggests that tumors of the four patients which exhibited atypical features in culture behaved more aggressively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691578
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  • 84
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    Electronic Resource
    Primary cerebral neuroblastoma: A light and electron microscopic study (1978)
    Springer
    Acta neuropathologica 41 (1978), S. 119-124 
    Details
    ISSN: 1432-0533
    Keywords: Neuroblastoma ; Small-cell neoplasm ; Cerebral ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A small-cell neoplasm in the left temporal lobe of a 10 and a half year old boy was studied by light and electron microscopy. Routine sections of the mass showed a differentiating neuroblastoma with Homer Wright rosettes, several foci of immature neoplastic neurons (ganglion cells), many mitoses, arcas of necrosis and tumor vessels showing endothelial proliferation. Ultrastructurally, most cells resembled early fetal neuroblasts and also were similar to those in murine and peripheral human neuroblastomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689762
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  • 85
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    Electronic Resource
    Dysplastic gangliocytoma of the cerebellum—An ultrastructural study (1978)
    Springer
    Acta neuropathologica 42 (1978), S. 1-5 
    Details
    ISSN: 1432-0533
    Keywords: Dysplastic gangliocytoma ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of dysplastic gangliocytoma of the cerebellum, a rare disorder with unknown etiology and pathogenesis, was studied ultrastructurally. The intranuclear inclusions identified were not seen to be of viral origin. The ultrastructural characteristics of the abnormal cells support the prevailing theory that these cells represent hypertrophied granular neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01273258
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  • 86
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    Electronic Resource
    The spreading of focal brain edema induced by ultraviolet irradiation (1978)
    Springer
    Acta neuropathologica 42 (1978), S. 223-229 
    Details
    ISSN: 1432-0533
    Keywords: Irradiation edema ; Gravimetry ; Ultrastructure ; Vesicular transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Focal brain edema limited to one cerebral hemisphere was produced by ultraviolet irradiation of the exposed cortex. Tissue water content was determined by the gravimetric method which allows microsampling. Therefore, the spread of edema around the small necrotic area could be mapped more precisely than by determination of dry weight which calls for larger samples. As early as 30 min following irradiation, hyperemia and swelling of the brain are observed under the operating microscope. This correlates with venous stasis, hyperemia, and broadened perivascular spaces around venules and large capillaries accompanied by a marked rise in the specific weight of the tissue. After 4 h an edema front can be observed spreading from the perinecrotic zone in which there is a marked rise in endothelial cell vesicular activity. Edema reaches maximum levels in the deep white matter at 48 h post irradiation with normalisation of the tissue water content after 96 h. The velocity at which the edema front spreads from the cortex to the periventricular area lies in the range of 0.25 mm/h. Edema reabsorption coincides with signs of retrograde micropinocytosis in endothelial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690361
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  • 87
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    The effects of cytochalasin B and colchicine on cell motility and ultrastructure in primary cultures of malignant gliomas (1978)
    Springer
    Acta neuropathologica 44 (1978), S. 21-30 
    Details
    ISSN: 1432-0533
    Keywords: Tissue cultures ; Cytochalasin B and colchicine ; Cell motility ; Ultrastructure ; Glioma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Primary tissue cultures of human gliomas were treated with cytochalasin B (0.5–60 μg/ml for 90 min). Cell motility was inhibited irreversibly in glial tumour cells, but the effect was reversible on the mesenchymal cells growing in culture in the lower dose range. Cell adhesion was considerably reduced as the dose was increased, as was the capacity for cells to spread on a surface from suspension. Low concentrations of cytochalasin B caused negligible cell death and little disruption of cell ultrastructure. However, increases in dose were accompanied by a greater predominance of rough endoplasmic reticulum and inclusions and aggregation of microfilament bundles. As seen by scanning electron microscopy, cytochalasin B caused the withdrawal of peripheral cell borders, disappearance of ruffles and the breakdown of cytoplasmic lamellae. Charateristic surface blebs and folds appeared in their place. By comparison, colchicine (1–10 μg/ml) caused a less marked and non-specific reversible reduction in cell motility on both glial and mesenchymal cells. No significant change in cell adhesion or spreading took place even at high doses, although at all concentrations gross disruption of the cell surface took place with changes in ultrastructure characterised by loss of cytoplasmic microtubules and aggregation of 10 nm filaments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691635
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  • 88
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    Retention of the differentiated state by larvalXenopus liver cells in primary culture (1978)
    Springer
    Development genes and evolution 185 (1978), S. 235-248 
    Details
    ISSN: 1432-041X
    Keywords: Liver ; Primary culture ; Ultrastructure ; Albumin synthesis ; Xenopus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Electron microscopic analysis of primary cultures derived from larvalXenopus liver has shown that these cells, although they form only two-dimensional aggregates, retain and presumably also develop structural characteristics typical of liver parenchyma cells, such as bile canaliculi with microvilli and epithelial junctional complexes. As judged from structural criteria, primary cultures contain 80–90% hepatocytes. In contrast to the intact tissue, primary cultures showed excessive development of microfilaments, however. Incorporation of labeled amino acids has revealed further that the capacity for protein synthesis is maintained in culture and that synthesis of liverspecific protein albumin is maintained in vitro, even in liver cultures derived from thyrostatic tadpoles. This latter result suggests that initiation of albumin synthesis in the larval liver is probably not dependent upon thyroid hormones but rather reflects the protodifferentiated state of this tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848354
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  • 89
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    Ultrastructure, histology, and innervation of the mantle edge of the freshwater pulmonate snailsLymnaea stagnalis andBiomphalaria pfeifferi (1978)
    Springer
    Calcified tissue international 26 (1978), S. 271-282 
    Details
    ISSN: 1432-0827
    Keywords: Shell formation ; Free nerve endings ; Ultrastructure ; Lymnaea stagnalis ; Biomphalaria pfeifferi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The mantle edge of the freshwater pulmonate snailsLymnaea stagnalis andBiomphalaria pfeifferi was investigated with histochemical and ultrastructural methods. The mantle edge gland, which is involved in shell formation, consists of the periostracal groove and the belt. This belt appears to be composed of various regions. In the area of the periostracal groove a number of subepithelial gland cell types occur; these release their products into the groove. Between the groove cells ciliated free nerve endings terminate; the corresponding perikarya occur in the subepidermal connective tissue. Also in the posterior belt region free nerve endings were observed between the epithelial cells; in addition, a particular type of subepithelial gland cell was found in this area. The epithelial cells of this part of the belt have the ultrastructural characteristics of ion and water transporting cells; they are probably involved in calcium deposition and resorption. The possible role of the free nerve endings and of the subepithelial gland cells is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013270
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  • 90
    Electronic Resource
    Electronic Resource
    Whole-body retention of mercury and selenium and histopathological and morphological studies of kidneys and liver of rats exposed repeatedly to mercuric chloride and sodium selenite (1978)
    Springer
    Archives of toxicology 40 (1978), S. 189-199 
    Details
    ISSN: 1432-0738
    Keywords: Mercury ; Selenium ; Retention ; Liver ; Kidney ; Ultrastructure ; Interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Distribution and retention of mercury and selenium was studied in rats exposed repeatedly to HgCl2 injections (0.5 mg Hg/kg to the tail vein every other day) and intragastrically to Na2SeO3 (0.5 mg Se/kg every day), applying combined and separate administration of these metals for 2 weeks. Whole-body retention of mercury in the presence of selenium was augmented by 20% and that of selenium in the presence of mercury by 4% with respect to the administered dose. Combined administration of mercuric chloride and sodium selenite brought about damage to the epithelial cells of renal proximal convolutions and formation of protein casts in their lumen. These changes had the same pattern as those induced by administration of mercuric chloride alone, but the intensity was lower. Submicroscopic studies revealed that repeated combined administration of sodium selenite and mercuric chloride did not completely abolish the mercury-induced mitochondrial swelling and contributed to chromatin destruction in the hepatocyte nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00364650
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  • 91
    Electronic Resource
    Electronic Resource
    Über das Vorkommen sog. heller Zellen in Speicheldrüsentumoren (1978)
    Springer
    Journal of cancer research and clinical oncology 91 (1978), S. 165-182 
    Details
    ISSN: 1432-1335
    Keywords: Clear cells ; Salivary gland tumors ; Ultrastructure ; Differential diagnosis ; Helle Zellen ; Speicheldrüsentumoren ; Ultrastruktur ; Differentialdiagnose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Zu den hellzelligen Speicheldrüsentumoren gehören monomorphe hellzellige Adenome, hellzellige Carcinome, hellzellige Varianten der Acinus- und Mucoepidermoidtumoren, Talgdrüsentumoren, Speichelgang-Carcinome und pleomorphe Adenome mit hellzelligen Abschnitten. Der lichtmikroskopische, deskriptive Begriff der hellen Zelle umfaßt bei einer weiteren cytochemischen und elektronenmikroskopischen Analyse Zellformen unterschiedlicher Herkunft und funktioneller Bedeutung. Folgende Zelltypen wurden näher analysiert: indifferente Gangzellen (geringe Organellenausbildung, Desmosomen), speichernde Streifenstückzellen (Glykogengranula, zahlreiche Mitochondrien, basales Labyrinth), Myoepithelzellen (Myofilamente, Pinocytose-Vesicel, Lipofuscingranula, Hemidesmosomen), epidermoide Zellen (Tonofilamente, Desmosomen), Becherzellen (Schleimvacuolen, basales endoplasmatisches Reticulum), Talgdrüsenzellen (Lipidtropfen, Mikrovilli, Desmosomen) und helle Acinuszellen (elektronenoptisch helle Sekretgranula, kleine Mitochondrien, kleiner Golgiapparat). In die Differentialdiagnose müssen auch hellzellige Tumorformen der Speicheldrüsenregion einbezogen werden, welche primär nicht vom Speicheldrüsengewebe ausgehen. Hierzu gehören Metastasen hypernephroider Nieren-Carcinome, Paragangliome, Glomustumoren Masson, Granularzelltumoren und alveoläre Weichteilsarkome.
    Notes: Summary Clear cell tumors of the salivary glands are monomorphic clear cell adenomas, clear cell carcinomas, clear cell variants of acinic cell and mucoepidermoid tumours, sebaceous cell tumors, salivary duct carcinomas and pleomorphic adenomas with clear cell sectors. At the light microscopical level the descriptive term of the clear cell comprises cell types of different origin and functional importance which can be differentiated by cytochemistry and electron microscopy. The following cell types were analysed precisely: indifferent duct cells (small formation of organelles, desmosomes), storing striated duct cells (glycogen granules, multiple mitochondrias, basal labyrinth), myoepithelial cells (myofilaments, pinocytosis vesicles, lipofuscin granules, hemidesmosomes), goblet cells (mucous vacuoles, basal endoplasmatic reticulum), sebaceous cells (lipid droplets, microvilli, desmosomes) and clear acinic cells (electron pale secretory granules, small mitochondrias, small golgi apparatus). Clear cell tumor types of the salivary gland region which primarely do not derive from the salivary gland tissue must also be included in the differential diagnoses. These are metastases of hypernephroid renal carcinomas, paragangliomas, glomus tumors of Masson, granular cell tumor and alveolar soft-part sarcomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00284023
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  • 92
    Electronic Resource
    Electronic Resource
    Ultrastructural studies on hydantoin induced lymphomas in mice (1978)
    Springer
    Journal of cancer research and clinical oncology 91 (1978), S. 195-204 
    Details
    ISSN: 1432-1335
    Keywords: Hydantoin ; Malignant Lymphoma ; Mice ; Ultrastructure ; Hydantoin ; Maligne Lymphome ; Maus ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ultrastrukturelle Zellveränderungen werden beschrieben am Original-Tumorgewebe und an Tumorzellen aus der Kurzzeitkultur von malignen Lymphomen, induziert durch chronische Diphenylhydantoin-Exposition. Diese Tumoren entstanden in Mäuse-Inzuchtlinien mit niedriger (C57Bl) und hoher (SJL/J) spontaner Lymphomrate im fortgeschrittenen Alter, waren jedoch nicht induzierbar in einer Lymphom-resistenten Linie (C3Hf). Frühveränderungen des lymphoretikulären Gewebes bestanden in einer zunehmenden Atrophie des Thymus und der thymusabhängigen Partien, begleitet von einer diffusen retikulo-histiozytären Hyperplasie. Lymphome vom lymphoblastischen Typ entstanden im Thymus nach einer Latenzzeit von 4–8 Monaten mit nachfolgender Generalisation. Verschiedene atypische Veränderungen wurden an Tumorzellen beobachtet sowie das Auftreten von C-Typ-Partikeln in den Tumorzellkulturen und hinsichtlich der Pathogenese der Lymphome diskutiert.
    Notes: Summary Ultrastructural studies were done on cells from original tumors and from short time cultures of mouse thymic lymphomas experimentally induced by chronic exposure to diphenyl-hydantoin. The tumors appeared in mouse strains with low (C57Bl) and high (SJL/J) susceptibility to spontaneous lymphoma development and were not observed in a resistant strain (C3Hf). Thymic lymphoma development was usually preceded by increasing lymphoreticular atrophy followed by progressive reticulohistiocytic hyperplasia, and subsequently spread to other tissues. Morphologically the tumor was characterized as a lymphoblastic lymphoma. Abnormal cell changes in the original tumors and cultured cells, and the presence of murine C-type particles in the cultured cells but not in the original tumors, are discused in relation with the disturbance of immune system and the lymphoma enhancement produced by diphenyl-hydantoin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00284026
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  • 93
    Electronic Resource
    Electronic Resource
    Disappearence of the intracytoplasmic membranes inRhodopseudomonas sphaeroides (1978)
    Springer
    Archives of microbiology 117 (1978), S. 293-295 
    Details
    ISSN: 1432-072X
    Keywords: Rhodopseudomonas sphaeroides ; Intracytoplasmic membranes ; Membranes ; Ultrastructure ; Bacteriochlorophyll ; Chromatophores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic bacterium,Rhodopseudomonas sphaeroides, can be grown phototrophically (light, anaerobiosis), of chemotrophically (dark, aerobiosis). In the first case, it contains intracytoplasmic membranes with photosynthetic pigments. When shifted from phototrophy to chemotrophy these membranes disappear in an unknown fashion. In the present experiment, samples were taken for electron microscopy, cell density and bacteriochlorophyll determinations after shift from phototrophy to chemotrophy. The density of intracytoplasmic vesicles was measured on micrographs. During the first 2h growth is very slow and the ultrastructure remains unaltered. As growth resumes, the vesicles disappear at a rate which implies that they are not incorportated into the cytoplasmic membrane, nor actively digested, but remain intact and become increasingly diluted in the cytoplasm as the culture grows. The size of the vesicles was estimated to about 500 Å. The number of vesicles in phototrophically grown cells was calculated to about 575 per cell, and after 6h chemotrophic growth to about 100. The areas of the cytoplasmic and intracytoplasmic membranes are roughly calculated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00738549
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  • 94
    Electronic Resource
    Electronic Resource
    Sporogenesis in Streptomyces melanochromogenes (1978)
    Springer
    Archives of microbiology 118 (1978), S. 309-316 
    Details
    ISSN: 1432-072X
    Keywords: Streptomyces melanochromogenes ; Sporogenesis ; Formation of sporulation septum ; Delimitation, separation, and release of spores ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mode of spore differentiation in a strain of Streptomyces melanochromogenes was followed by analysis of ultrathin sections of sporulating aerial hyphae at various stages of sporogenesis. A special accent was laid on the formation of the sporulation septum and its alterations in the course of spore delimitation and separation. Distinct differences in formation and substructure have been observed between the cross walls of vegetative hyphae and the sporulation septa. Cross walls of vegetative hyphae are formed in a way typical for Gram-positive bacteria by a centripetal annular ingrowth of cytoplasmic membrane, on which wall material immediately is deposited. The development of the sporulation septa is characterized by the accumulation of amorphous material in addition to the newly synthesized wall layer inside the invaginating cytoplasmic membrane. This amorphous septal material will later be decomposed presumably by two lytic systems which cause the separation of the spores. The central region of the finished sporulation septum is perforated by microplasmodesmata. Spores are released by a break down of the surface sheath. The complete spores are enveloped by a twolayered cell wall and the spiny surface sheath.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429123
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  • 95
    Electronic Resource
    Electronic Resource
    Ultrastructural study of microcyclic macroconidiation in Neurospora crassa (1978)
    Springer
    Archives of microbiology 116 (1978), S. 279-288 
    Details
    ISSN: 1432-072X
    Keywords: Neurospora crassa ; Macroconidia ; Microcycle ; Heat ; Ultrastructure ; Nucleolus ; Proconidia ; Septa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Heat-shock of macroconidia of Neurospora crassa at 46°C followed by shift-down to 25°C determines premature conidiogenesis. The nuclei and cytoplasm of heat-treated, swollen conidia contain spots of a dense material especially concentrated around the nucleolus in short time treated ones. In the first proconidium apically budding on the enlarged tip of the premature conidiophore, small vesicles are peripherally spread. A few such vesicles are later seen lining the initially simple septum separating the proconidial units into conidia. The doubling of this interconidial septum is surface viewn as a thick annulus. Disarticulation of the conidial units intervenes along a septal furrow of electroluscent material. Interconidial continuity through the septal pores is transiently insured by a connective which is ruptured for final liberation of the conidia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00417852
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  • 96
    Electronic Resource
    Electronic Resource
    Kleinhirnastrocytome und Opticusgliome — eine vergleichende feinstrukturelle Untersuchung (1978)
    Springer
    Virchows Archiv 380 (1978), S. 59-79 
    Details
    ISSN: 1432-2307
    Keywords: Cerebellar astrocytoma ; Optic glioma ; Pilocytic astrocytoma ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An ultrastructural comparison of 8 cerebellar astrocytomas and 4 optic gliomas shows that the morphological patterns of both tumor-groups are identical. The confusion in nomenclature of these tumors is discussed and reasons for a preference for the term “pilocytic astrocytomas” are given. Further, pilocytic astrocytes seem to be a special, phylogenetically older, group of glial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00432893
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  • 97
    Electronic Resource
    Electronic Resource
    Immunhistochemical and electron microscope analysis of adenomas of the thyroid gland (1978)
    Springer
    Virchows Archiv 380 (1978), S. 205-220 
    Details
    ISSN: 1432-2307
    Keywords: Thyroid ; Adenoma ; Ultrastructure ; Immunhistochemistry ; Thyroglobulin ; Lysosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Histological, immunhistochemical and electronmicroscopic studies of 12 human, scintigraphically “cold”, thyroid adenomas with specific cytological differentiation identified four different cell types: oxiphil cell, clear cell, ergastoplasm-rich cell and mitochondrion-rich cell. The oxiphil tumor cell can be recognized light-microscopically by its large size and its eosinophilic granular cytoplasm. Most of these cells do not produce thyroglobulin. The ultrastructural characteristics of oxyphil cells are principally mitochondria in great numbers and many large lysosomes. Clear cell adenomas show a trabecular growth pattern. The tumor cells have an abundance of cytoplasm which contains small acidophilic granules. Immunhistochemically we were able to demonstrate thyroglobulin in small amounts within cytoplasmic granules and more extensively within the follicle lumina. Electronmicroscopically we observed a large number of smooth surfaced vacuoles of varying size, extraordinary large lysosomes and occasional cisternae of rough endoplasmic reticulum, the latter probably corresponding to the immune-histochemically identified thyroglobulin granules. The ergastoplasm-rich-cell adenomas, which to the best of our knowledge have not been previously described, show a predominantly micro-to normofollicular architecture histologically without intrafollicular colloid. The cytoplasm of the ergastoplasm-rich cells reveales a strong positive thyroglobulin-staining reaction. The fine structure of these cells is characterized by the abundance of cisternae of the rough endoplasmic reticulum. The mitochondrion-rich-cell adenomas exhibited a microfollicular structure with an intensive acidophilic granular staining at the basal part of the tumor cells. Immunhistochemically and electronmicroscopically we found some morphologic and functional features which differentiate these cells from the oxyphil cell. Thyroglobulin was located predominantly in the apical portion of the cytoplasm in the mitochondrion-rich cells without sharp demarcation from the luminar thyroglobulin. Electron microscopically fewer basal and laterally located mitochondria were seen in mitochondrion-rich cells compared with oxyphil cells. As we could not find any sign of functional activity in the oxyphilic, clear cell and ergastoplasm-rich cell adenomas we analysed those aspects of the lysosomal system not concerned with the enzymatic digestion of thyroglobulin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00430459
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  • 98
    Electronic Resource
    Electronic Resource
    A freeze-fracture study of tight junctions in the pars convoluta and pars recta of the renal proximal tubule (1978)
    Springer
    Cell & tissue research 186 (1978), S. 121-133 
    Details
    ISSN: 1432-0878
    Keywords: Proximal tubule ; Tight junctions ; Ultrastructure ; Electron microscopy ; Freeze fracturing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of tight junctions of the renal proximal tubule was studied comparing the pars convoluta and pars recta of rat, golden hamster, rabbit, cat, dog and tupaia. Though some interspecies variations were observed, the convoluted portions of the proximal tubules revealed quite uniformly very leaky tight junctions with mainly 1–2 strands. Along the whole proximal tubule of the rabbit kidney including the pars recta only minor differences of the zonulae occludentes were found. By contrast, the tight junctions of the pars recta in other species were much more elaborate, especially in cat and tupaia, having up to 6 strands and an overall depth of more than 150 nm. The implications of these findings are discussed with special regard to the functional differences between the pars convoluta and pars recta of the proximal tubule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219659
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  • 99
    Electronic Resource
    Electronic Resource
    Exocrine pancreas under experimental conditions (1978)
    Springer
    Cell & tissue research 186 (1978), S. 227-240 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas (rat) ; Pancreatic duct ligation ; Cell membrane ; Intercellular junctions ; Ultrastructure ; Freeze fracture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Exocrine pancreatic tissue was investigated during various intervals after pancreatic duct ligation. Concomitant to the increase of the intraluminal pressure, alterations are found in the arrangement of the luminal membrane surface and the zonulae occludentes of the acinar cells. The zonulae occludentes exhibit a disarrangement of their strands. The number of strands diminishes and small interruptions as well as large discontinuities of the strands are observed in most regions of the acinar cells. Furthermore, gap junctions are found very infrequently between acinar cells. The ultrastructural alterations of the zonulae occludentes suggest a gradual adaptation to the increasing unilateral pressure. However, a leakage of the paracellular permeability barrier occurs which contributes to the known shunt between the compartments of the pancreatic juice and the interstitial space following pancreatic duct obstruction. The present investigation is a further example of alterations in the paracellular permeability and intercellular communication of epithelial cells under pathological conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225533
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  • 100
    Electronic Resource
    Electronic Resource
    Fine structure of the eyes of orb-weavers, Argiope amoena L. Koch (Aranea: Argiopidae) (1978)
    Springer
    Cell & tissue research 186 (1978), S. 435-452 
    Details
    ISSN: 1432-0878
    Keywords: Photoreceptors ; Arthropod ; Spider (Argiope amoena) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anterolateral eye, the posterolateral eye and the posteromedial eye of the web-building spider, Argiope amoena have been examined by light and electron microscopy. The dioptric apparatus of all three eyes is similar in structure, and consists of a cornea, a lens and a vitreous body. The retina contains monopolar receptor cells, the cell bodies of which are present beneath the vitreous body in all three eyes. Proximal processes of the receptor cells form rhabdoms beneath the cell body layer and then extend toward the first optic glomerulus as an ocellar nerve. Two distinct patterns of retinal organization are present in the three eyes. In one type the rhabdomic layer of the retina is backed by a pigmented layer. In the other type the rhabdomic layer is backed by a tapetal reflecting layer. Rhabdomic structure and cytoplasmic inclusions of the receptor cells differ greatly between the two types. The anterolateral eye possesses a single type of retina with the rhabdoms backed by the tapetum. Both the posterolateral and the posteromedial eye are similar in structure, each possessing beneath the common dioptric apparatus retinae of both types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224933
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