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  • 1985-1989  (140)
  • 1970-1974
  • 1935-1939
  • 1989  (64)
  • 1987  (76)
  • Ultrastructure
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 414 (1989), S. 113-119 
    ISSN: 1432-2307
    Schlagwort(e): Gastric mucosa ; Intestinal metaplasia ; Ciliated cell ; Ciliated metaplasia ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Intestinal metaplasia of the gastric mucosa occurs commonly in aged Japanese patients and has been discussed in relation to the high incidence of gastric cancer in Japanese. Ciliated cells in the gastric mucosa have frequently been found in association with intestinal metaplasia in the pyloric gland and rarely in the cardiac gland in many Japanese patients, and exceptionally in one Chinese and in one Swedish patient. Electron microscopic examination of 12 Japanese patients has revealed that these structures are not metaplastic stereocilia, but true cilia. Ciliated cells have been found in the basal part of the gastric glands and never in the surface epithelium. The fine structure of the gastric cilia was almost the same as that of normal respiratory cilia. However, in the gastric cilia, most dynein arms were inconspicuous even after tannic acid fixation, indicating that ciliary beating of the gastric cilia is problematic. Abnormal cilia and basal bodies also were found. Ciliated cells have always occurred in association with intestinal metaplasia, therefore this phenomenon might be a type of metaplasia and is named “ciliated metaplasia” of the gastric mucosa.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 414 (1989), S. 459-464 
    ISSN: 1432-2307
    Schlagwort(e): Sebaceous carcinoma ; Parotid gland ; Salivary gland ; Ultrastructure ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Sebaceous carcinoma of salivary gland origin is extremely rare and, because of its rarity, the clinicopathological characteristics and the histogenesis are not fully understood. We present a case of sebaceous carcinoma of the parotid gland which brings the total number of reported cases to 22. The tumor showed epithelial cell nests which were mainly composed of sebaceous cells with marked cellular atypia. In most of the nests, glandular spaces lined by ductal epithelium were present. Scattered mucous cells and flattened eosinophilic cells at the periphery of the nests were also seen. Ultrastructural and immunohistochemical observations of the tumour revealed coexistence of sebaceous and glandular differentiations in some tumour cells. Tumour cells with lipid granules often participated in the formation of glandular structures or exhibited intracytoplasmic lumina, and immunohistochemical localization of lactoferrin and secretory component, the functional markers of ductal epithelium of salivary gland, was demonstrated not only in duct-forming tumour cells but also in many sebaceous tumour cells. It seems likely that sebaceous carcinoma originates from pluripotential duct cells which can differentiate into sebaceous, ductal and mucous cells.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 415 (1989), S. 145-149 
    ISSN: 1432-2307
    Schlagwort(e): Paracrystalline inclusion ; Microtubule ; Ciliogenesis ; Gastric ciliated cell ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Unusual electron-dense paracrystalline inclusions were found in metaplastic ciliated cells in the stomachs of three Japanese male patients with gastric carcinoma. These patients had not been given antitumour drugs before surgery and ethrane (enflurane) was used as the anaesthetic. Ciliated cells in the gastric mucosa are found not infrequently in the pyloric glands in association with intestinal metaplasia in elderly Japanese patients. Paracrystalline inclusions were found only in the ciliated cells and never in any other types of gastric mucosal cell. These inclusions were located in the apical portion of the ciliated cells in intimate association with the basal bodies. They consisted of twisted strings about 27 nm wide with a regularly repeated spacing of about 30 nm. On highly magnified electron micrographs, granules about 4 nm in diameter were detected. These paracrystalline inclusions have never been reported previously, although their location in ciliated cells and their morphological characteristics suggest an intimate relationship with the ciliogenesis of metaplastic ciliated cells in the human stomach.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1432-2307
    Schlagwort(e): Malignant fibrous histiocytoma ; Ultrastructure ; Enzyme histochemistry ; Immunohistochemistry ; “Fibrohistiocytoid cell”
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural, enzyme histochemical and immunohistochemical studies were performed on tissue obtained from eight cases of malignant fibrous histiocytoma (MFH) and five cases of sacral decubitus ulcer. The MFH was composed of two major tumour cell types: fibroblast-like and histiocyte-like cells. Both cell types demonstrated abundant branching, fragmented rough endoplasmic reticulum (rER), many free ribosomes, occasional small mitochondria, an oval, elliptical or irregularly shaped nucleus with one or two prominent nucleoli and often a few dense bodies. However, pseudopodial projections, multivesicular bodies and phagosomes, common histiocyte organelles, were not seen. With little difference between cases or selection sites, the MFH cells reacted to acid phosphatase (AcP) and α-naphtyl butyrate esterase (ANBE) by enzyme histochemistry and with ferritin (Fer), α1-antitrypsin (AT), α1-antichymotrypsin (ACT), fibronectin (FN), HLA-DR, HLA-DP, Leu 10 and OKT 9 in immunohistochemical studies. MFH tumour cells did not immunostain with monocyte/macrophage markers (Leu M1, Leu M3, Mo 1, Mo 2 and Macrophage) although non-neoplastic histiocytes did react to these markers. In addition, granulation tissue, such as that found in sacral decubitus ulcers, was examined and the existence of a specific cell type called the “fibrohistiocytoid (FH) cell” was documented. The FH cell was short, spindle shaped and elliptical. Ultrastructurally, it had fragmented rER distributed in a branching pattern, dispersed free ribosomes, small mitochondria and a few dense bodies, but lacked diverse fused lysosomes and distinct pseudopodial cytoplasmic extensions. The FH cells reacted with AcP, alkaline phosphatase and ANBE but not with peroxidase using enzyme histochemistry and with Fer, AT, ACT, FN, HLA-DR, HLA-DP, Leu 10 and OKT 9 but not with monocyte/macrophage markers, C3d receptor, C3bi receptor in immunohistochemical studies. The FH cells had morphological, enzyme histochemical and immunohistochemical characteristics intermediate between fibroblasts and histiocytes. Similarities between MFH cells and the FH cells seen in chronic inflammation are discussed.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 415 (1989), S. 21-29 
    ISSN: 1432-2307
    Schlagwort(e): Alcoholic liver disease ; Ultrastructure ; Phagocytosis ; Cell shedding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Sinusoidal macrophages were studied by light and electron microscopy in 49 liver biopsies from alcohol-abusers with a variety of alcohol-related liver lesions or with near-normal livers. Changes were related to those in nearby hepatocytes. A reduction in the number of macrophages was noted in the more severely damaged livers. Hepatocytes formed blebs at their sinusoidal poles, and these protruded into the space of Disse and into the sinusoidal lumen. It is postulated that reduced phagocytic activity in the livers of patients with severe alcohol-related liver disease leads to increased shedding of hepatocellular material into the circulation. This may promote the development of autoimmune reactions directed against hepatocytes.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 77 (1989), S. 599-604 
    ISSN: 1432-0533
    Schlagwort(e): Neuronal inclusions ; Leigh disease ; Tropomyosin ; Actin ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A novel type of non-viral cytoplasmic inclusion is described, which was seen in virtually every neuron in the brain and spinal cord of a child with a presumed metabolic disorder whose clinical picture and CNS pathology were compatible with Leigh Syndrome. The ovoid to round inclusions were sharply demarcated, measuring up to 11 μm in diameter. They showed no distinctive staining with a battery of routine histological techniques. The ultrastructural features are unique, comprising non-membrane-bounded aggregates of randomly oriented plate-like structures with parallel linear densities depicting a periodicity of 11–16 nm. Immunocytochemical studies revealed strong staining with antisera to tropomyosin and weaker staining with antisera to actin. There was no reactivity with antibodies against neurofilaments, microtubules and their associated proteins, paired helical filaments, ubiquitin, vinculin or alpha-actinin. It is postulated that the metabolic disorder resulted in a neurodegenerative condition which manifested pathologically with lesions compatible with those of Leigh Syndrome. Associated with the condition was the discrete accumulation of cytoplasmic proteinaceous components, including tropomyosin, in the form of neuronal cytoplasmic inclusions possibly resulting from an alteration of the neuronal cytoskeleton.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-0533
    Schlagwort(e): Cerebral hypoxia ; Cerebral ischemia ; Ultrastructure ; Neocortex ; Brain isolation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The acute cortical response to surgical brain isolation and subsequent extracorporal normoxic or 30 min hypoxic (PaO2=20 mm Hg) perfusions (hypoxic hypoxia with relative ischemia) was evaluated. Cerebral blood flow, arterial pH and CO2 were maintained constant during both perfusions; only the arterial oxygen content was changed. The isolated brain model used in this and previous investigations produces no qualitative ultrastructural changes in the neocortex following brain isolation and normoxic perfusion. However, the acute cortical structural response to 30 min of hypoxic hypoxia with relative ischemia demonstrated a number of important observations. Hypoxic hypoxia produced ultrastructural responses common to cerebral ischemia such as nuclear chromatin clumping, nucleolar condensation and cytoskeletal breakdown. Although neuronal abnormalities seen after 30 min of hypoxic hypoxia were similar to those acute neuronal changes observed following complete cerebral ischemia without recirculation, they differed three ways: (a) mitochondrial swelling and microvacuolation were observed in many cortical pyramidal neurons. (b) Glycogen particles within astroglial processes were observed even after a 30-min period of hypoxic hypoxia. (c) Perivascular astroglial swelling was minimal despite considerable perineuronal swelling. In contrast, incomplete cerebral ischemia produces mitochondrial changes similar to those in hypoxic hypoxia but also causes the depletion of tissue glycogen and perivascular glial swelling. Thus, hypoxic hypoxia with relative ischemia produces a unique acute ultrastructural response compared to either complete or incomplete cerebral ischemia.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 79 (1989), S. 168-175 
    ISSN: 1432-0533
    Schlagwort(e): Muscular ; Dystrophy ; Ovine ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The initial ultrastructural changes in skeletal myofibers in ovine muscular dystrophy (MD) consisted of focal degeneration of myofibrils and the formation of Z-disc abnormalities, including nemaline rods, in adjacent sarcomeres. Peripheral and central sarcoplasmic masses, which occurred initially in large diameter fibers, contained a mixture of normal organelles and abnormal tubular and fibrillar formations. Vesiculate sarcolemmal nuclei with prominent nucleoli accumulated in central and subsarcolemmal locations in small clusters and short rows. Deformed individual nuclei were sometimes present within nuclear rows. Loss of the myofibrillar mass, increased density of small spherical nuclei, collections of fibrillar and tubular arrays, excessive folding of the sarcolemma and greatly reduced fiber diameter were seen in the end stage of the dystrophic process. Resting satellite cells were present at all stages of lesion development. The morphological progression of the lesions suggested an inherited inability to effectively replace lost myofibrils with ultimate exhaustion of the capacity for repair followed by pathological fiber atrophy.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 180 (1989), S. 175-178 
    ISSN: 1432-0568
    Schlagwort(e): Paratympanic organ ; Reciprocal synapses ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The innervation pattern of the paratympanic organ was studied by TEM. The paratympanic organ is a small tapering vesicle, typical of birds, situated in the medial wall of the tympanic cavity; it contains hair cells which are similar to type II receptors of the acoustic-lateral system; these cells are characterised by synapses which are not only afferent and efferent, as previously described, but also reciprocal with efferent fibers. Our observation revealed some efferent nerve fibers which form a relationship with hair cells containing synaptic bodies situated next to the plasma membrane and near the fibers themselves. Since synaptic bodies are commonly considered to be the site where the transmission of the impulse from the receptor to the nerve fiber takes place, our pictures suggest that the efferent fibers and hair cells may be either presynaptic or postsynaptic with respect to each other in the paratympanic organ. The hypothesis is formulated that reciprocal synapses allow interaction between hair cells, thus determining an increase in the contrast of information sent by the paratympanic organ to the CNS.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1432-0568
    Schlagwort(e): Cecum ; Germ-free rat ; Microflora inoculation ; Morphometry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The structural changes of the cecal wall in germfree rats were observed at regular intervals after the inoculation of fecal microflora from conventional rats. Quantitative light microscopy showed that most of the elements in the cecal wall increased at 12 or 24 h and reached peak values at 4 days after inoculation. On the 7th day, they decreased approximately to the values for conventional rats. The crypts were bent or widely open till 24 h but were not after the 4th day. Hyperplasia of the crypt epithelial cells including mucous-type cells was observed following microbial inoculation. Electron microscopy revealed that most of the epithelial cells lining the mucosa were typical columnar cells. Desquamation of the epithelial cells and contraction of the muscle fibers were often seen on 4th day. The mucous-type cells were divided into two types, goblet and non-goblet mucous-type cells. Reduction of cecal volume after microbial inoculation may be mainly caused by muscle contraction in the early period and hyperplasia and desquamation of the epithelial cells may suggest their role as the first and non-specific defense line prior to operation of the specific immune system.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 179 (1989), S. 435-442 
    ISSN: 1432-0568
    Schlagwort(e): Ultrastructure ; In vitro fertilization ; Bovine ; Ova ; Cortical granules
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Heifers were superovulated by PMSG or FSH, and oestrus was induced by prostaglandin. One group of animals was ovariectomized 19–26 h after the LH peak, the content of preovulatory follicles aspirated, and the oocytes processed for in vitro fertilization. Another group was inseminated and ova were collected from the oviducts for study of in vivo fertilization. All ova were examined ultrastructurally. The developmental rate following in vitro fertilization was delayed compared to fertilization in vivo. A high proportion of the in vitro fertilized ova showed polyspermic penetration of the zona pellucida, and supernumerary spermatozoa were found in the ooplasm of some ova. In vivo fertilization was associated with release and subsequent dispersal of the cortical granule content in the perivitelline space. In contrast to this the released granule content of the in vitro fertilized ova remained undispersed close to the oolemma. This feature may account for the high incidence of polyspermic penetration of the zona pellucida. In addition, the study provided an ultrastructural visualization of the initial contact between the equatorial segment of the spermatozoon and the microvilli of the oocyte, and the subsequent internalization of the sperm head.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 179 (1989), S. 497-501 
    ISSN: 1432-0568
    Schlagwort(e): Parotid gland ; Ultrastructure ; Amylase ; Secretion ; Isoproterenol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of continuous light on ultrastructural organization and sympathetic secretory responses of the rat parotid gland are reported. After 50 days of continuous light exposure, the fine structure of the parotid gland exhibited features of enhanced secretory activity as judged by the striking development of rough endoplasmic reticulum and Golgi complexes, the depletion of secretory granules and the increased turnover of secretory cells. The secretory responses of parotid gland to isoproterenol revealed that continuous light induced a 30% increase in amylase release. This secretory hyperactivity appears to be related to a postsynaptic supersensitivity of sympathetic fibers of the autonomic nervous system.
    Materialart: Digitale Medien
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  • 13
    ISSN: 1432-0568
    Schlagwort(e): Sympathetic ganglion ; Binucleate cells ; Ultrastructure ; Feulgen staining ; Computerized image analysis ; DNA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The relative proportion, ultrastructure and DNA-content of the binucleate cells in the celiac superior mesenteric ganglion of the guinea pig was studied using light and electron microscopy as well as computerized image analysis of Feulgen stained cells. The number of mono — versus binucleate cells was found to vary with stage of development with about 40% of the cells being binucleate in adult animals and 50% in late prenatal stage. No difference in ultrastructure was observed between the nuclei of the two cell types. The binucleate cells contain twice the amount of DNA found in the mononucleate cells.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 179 (1989), S. 591-604 
    ISSN: 1432-0568
    Schlagwort(e): Fetus ; Membranes ; Placenta ; Green monkey ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This study examined developmental changes in fetal membranes and placenta of Cercopithecus aethiops from a Carnegie developmental stage 12 embryo to nearterm fetuses. Ultrastructurally, yolk sac cells (endoderm and mesothelium) were similar to comparable stages in other primates. Endodermal cells had few apical microvilli, abundant rough-endoplasmic reticulum, electron dense mitochondria and dense bodies. In contrast, mesothelial cells were squamous with numerous microvilli, small mitochondria and a few short strands of rough endoplasmic reticulum. Amnion cells early in gestation were squamous with few microvilli, large glycogen deposits and poorly developed cytoplasmic components. Tight junctions and desmosomes held adjacent cells together. The basal surface was smooth and the basal lamina was distinct. As development proceeded the amniotic cells became cuboidal and possessed numerous microvilli. Cytoplasmic organelles were better developed and glycogen deposits increased by mid-gestation. A thick layer of microfibrils and collagen fibers was prominent below the basal lamina. Near-term, the glycogen had virtually disappeared and the amount of lipid droplets increased. Basal infoldings and podocytic processes and the extracellular matrix had increased. The smooth chorion consisted of pseudostratified columnar cells. Cells had short microvilli, numerous granules and vesicles of variable size and electron density in early gestation. With increasing age, amounts of granules and vesicles decreased, as the endoplasmic reticulum became prominent. The chorionic trophoblast was a continuous layer in mid-pregnancy and its cells had well-developed organelles and inclusions. Late in gestation, the trophoblastic layer became discontinuous and wide intercellular spaces and channels were present. In the placenta, the trophoblastic elements showed features characteristic of primate placenta.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 180 (1989), S. 103-108 
    ISSN: 1432-0568
    Schlagwort(e): Ultrastructure ; Gut ; Endocrine cells ; Testudo graeca ; Chelonia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The digestive tract of Testudo graeca (Chelonia) was investigated by means of electron microscopy using both conventional and immunocytochemical techniques. EC-, L-, D-, G-, B-, N- and EC-L-cells were detected. These cells share several common ultrastructural characteristics with the endocrine cells of mammals (i.e. clear cytoplasm, prominent Golgi apparatus, secretory granules etc.). EC and D1 cells have so far not been described in the esophagus of any animal species; in the present study these cells have been observed in the esophagus of T. graeca. Of special interest was the presence of B-cells in the intestine, suggesting that the migration of B-cells from the gut to the pancreas to constitute pancreatic islets is not concluded in T. graeca. The present study demonstrates that the gut endocrine system of T. graeca is a complex structure containing a large variety of endocrine cell types similar in morphology to those found in higher vertebrates.
    Materialart: Digitale Medien
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  • 16
    ISSN: 1432-0568
    Schlagwort(e): Monkey ; Ultrastructure ; Pinealocytes ; Axon terminals ; Synapses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The present study described the normal ultrastructure of the monkey pineal gland. The gland was composed of the principal pinealocytes, intramural neurons and glial cells. The nucleus of the pinealocytes was deeply infolded with evenly distributed chromatin materials. The abundant cytoplasm was rich in organelles including the well-developed Golgi apparatuses, multivesicular bodies, dense-cored vesicles and widely scattered free and polyribosomes. A variety of axon terminals was observed and the majority of them contained pleomorphic agranular vesicles with a few large dense-cored vesicles. A few terminals showed flattened vesicles or small dense cored vesicles. Some of the axon terminals formed synaptic contacts with the cell bodies of pinealocytes. These synapses were mainly concentrated in the posterior third of the gland. The occasional intramural neurons observed were postsynaptic to axon terminals containing round agranular vesicles. The sources of the nerve fibres and terminals forming synaptic junctions with pinealocytes and intramural neurons were discussed.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 78 (1989), S. 72-85 
    ISSN: 1432-0533
    Schlagwort(e): 2,4-Dithiobiuret ; Thioimidodicarbonic diamide ; Motor endplate ; Neuromuscular junction ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 2,4-Dithiobiuret was given i.p. to rats for 4 days at a daily dosage of 1 mg/kg and the development of the lesion associated with neuromuscular dysfunction studied in hindlimb lumbrical muscles. The first morphological indication of neurointoxication was the appearance in some motor endplates of masses of branching tubular smooth endoplasmic reticulum (SER) on day 2 which correlated with the initial functional disturbances. By the 3rd day, most motor endplates were distended by accumulations of densecored, lucent and synaptic vesicles, abnormally swollen mitochondria, intermediate filaments and branching, tubular SER. Evidence of collateral axonal sprouting was seen first at this time. On days 4 and 5, many motor endplates were markedly enlarged and showed axoplasmic organelle congestion. A significant increase in synaptic vesicle size was noted at these times in some terminals. Interposition of Schwann cell processes between the pre- and postsynaptic membranes and terminal retraction was now evident. Some intramuscular nerves showed hydropic Schwann cell cytoplasm with separation of the outermost myelin lamellae, mitochondrial swelling and adaxonal vacuoles as early as the 1st day. Proliferation and segregation of SER around central cores of neurofilaments was seen in myelinated nerve fibres and preterminals on the 3rd day. At this and later times accumulations of SER and swollen mitochondria were found at sites of axonal varicosities and at the paranodal constrictions at nodes of Ranvier. These ultrastructural data are discussed with regard to reduced terminal Ca2+ content (demonstrated by oxalate-pyroantimonate cytochemistry) and compared with the sequelae of botulinum intoxication.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 79 (1989), S. 336-339 
    ISSN: 1432-0533
    Schlagwort(e): AIDS ; Cytomembranous inclusions ; Tubuloreticular inclusions ; Ultrastructure ; Peripheral nerve
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We report finding tubuloreticular inclusions (TRI) in the endothelial cells of endo- and epineurial vessels in the sural nerve of 11 patients with AIDS. Six patients had a painful peripheral neuropathy, one a non-painful sensory neuropathy, one an acute inflammatory demyelinating polyradiculoneuropathy and one a thalidomide-related neuropathy. Two patients had no clinical evidence of neuropathy. The TRI are not specific to one neuropathy and are unlikely to contribute to the pathogenesis of peripheral nerve syndromes in AIDS.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 77 (1989), S. 654-658 
    ISSN: 1432-0533
    Schlagwort(e): Melanotic neuroectodermal tumor ; Immunohistochemistry ; Ultrastructure ; Pineal origin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of a melanotic neuroectodermal tumor arising from pineal region of a 4-year-old girl is presented. The tumor had spread diffusely to the meninges, consistent with malignant behavior. Histologically, the tumor consisted primarily of epithelial elements arranged in tubules, cords and nests separated by fibrous vascular tissue in addition to a small neuroblastomatous focus. Melanin pigment was frequently observed in the epithelial tumor cells, and melanin-laden macrophages were also often observed. No teratoid elements were found. Immunohistochemically, tumor cells were positive for neuron-specific enolase but were nonreactive for S-100 protein, epithelial membrane antigen, glial fibrillary acidic protein, vimentin, α-fetoprotein and human chorionic gonadotrophin. Ultrastructurally, the epithelial nature of the tumor cells could be easily demonstrated. In addition, melanosomes in various stages in maturation were observed, indicating melanogenesis of the tumor. On the basis of the tumor location and the histological similarities previously observed for the fetal pineal body, it is very likely that this melanotic epithelial tumor could have originated from the fetal pineal gland.
    Materialart: Digitale Medien
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  • 20
    ISSN: 1432-0533
    Schlagwort(e): Gangliocytoma ; Ganglioglioma ; Ultrastructure ; Immunohistochemistry ; Neuroendocrine markers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We studied five cases of central nervous system neuronal tumor, one gangliocytoma and four gangliogliomas, both ultrastructurally and immuno-histochemically, using antibodies to neuroendocrine markers including tyrosine hydroxylase (TH), serotonin (5HT), somatostatin (SOM), met-enkephalin (MEK), leu-enkephalin (LEK), substance P (SP), gastrin, vasopressin, oxytocin, vasoactive intestinal polypeptide, adrenocorticotropic hormone and calcitonin. In all cases, the presence of dense-core vesicles (60–250 nm) in the neuronal elements was the characteristic ultrastructural finding. Synapses were observed in two cases. Immunohistochemically, variable numbers of neuronal cells showed positive staining for SOM in five cases, TH, MEK and LEK in three cases, and 5HT and SP in one case each. The others were negative. Positive immunoreactivity for multiple markers was shown in all cases. SOM, TH, 5HT and SP were present in the small- to medium-sized cells, while MEK and LEK were almost exclusively confined to the large cells. Our study clearly indicated that these tumors contained neuronal cells which were not homogeneous with regard to neuroendocrine markers.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 77 (1989), S. 258-266 
    ISSN: 1432-0533
    Schlagwort(e): Neurofibrillary tangles ; Alzheimer's disease ; Pick bodies ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We have studied the immunohistochemical reactivity and ultrastructure of both neurofibrillary tangles (NFTs) occurring with severe neurofibrillary diseases, and Pick bodies (PBs) associated with Pick's disease. The NFTs and PBs did not react immunohistochemically with the anti-nonphosphorylated neurofilament monoclonal antibody irrespective of whether they were pretreated with alkaline phosphatase. In granular neurons of the dentate fascia of Ammon's horn in cases of dementia of the Alzheimer type (DAT), NFTs either resembled PB-like inclusion bodies (Horoupian's inclusion bodies) in form, or had a perinuclear structure. Immunohistochemically and ultrastructurally, the NFTs in the dentate fascia in cases of DAT, including Horoupian's inclusion bodies, were similar to the NFTs in the pyramidal neurons of Ammon's horn, which are found most frequently in association with severe neurofibrillary diseases. Under a light microscope, Horoupian's inclusion bodies and PBs could not be differentiated and appeared to be argyrophilic round cytoplasmic inclusions in granular neurons of the dentate fascia. There were, however, ultrastructural differences. Horoupian's inclusion bodies consisted of bundles made up of straight tubules (STs), each about 15 nm in diameter. These bundles were intermixed with a few paired helical filaments which occurred at intervals of about 80 nm. On the other hand, PBs were composed of randomly distributed 15-nm-wide STs, intermixed with a very few fibrillary structures. These fibrils had a periodicity of about 160 nm, and ranged in width from about 15 nm to 30 nm. Horoupian's inclusion bodies associated with DAT and PBs associated with Pick's disease are different in this neuropathological aspect. The NFTs, including Horoupian's inclusion bodies in the dentate fascia in cases of DAT, are considered to be a manifestation of neurofibrillary degeneration.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 79 (1989), S. 86-93 
    ISSN: 1432-0533
    Schlagwort(e): Primary malignant CNS lymphoma ; Ultrastructure ; Intracytoplasmic tubuloreticular, membranous structures ; Intranuclear inclusions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural studies of 17 primary malignant CNS lymphomas revealed 6 tumors with abnormal intracytoplasmic and/or intranuclear membranous structures, most frequently, associated with the endoplasmic reticulum or perinuclear envelope. In most cases, tubuloreticular inclusions and paired cisternae were present. Less frequent were accumulation of mictotubules, concentric lamellar bodies, and rod-like or paracrystalline intranuclear inclusions. The specificity and significance of these membranous structures remain questionable because of their frequent occurrence in a variety of normal and pathological conditions. Some of these changes may be considered as cellular reactions to viral infections, others may indicate cellular activity or degeneration.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 281 (1989), S. 35-39 
    ISSN: 1432-069X
    Schlagwort(e): Pseudo-Kaposi's sarcoma ; Bluefarb-Stewart syndrome ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An ultrastructural study of the skin lesion of a young patient affected by pseudo-Kaposi's sarcoma of the Bluefarb-Stewart type (BSS) is reported. The neoplasm consisted of a proliferation of vascular structures mostly consisting of a solid bud of endothelial cells surrounded by a thinned and polystratified basement membrane and several pericytes. Both endothelial cells and pericytes were of normal ultrastructural appearance. Intervascular “stromal” cells were few and morphologically identified as macrophages and/or phagocytic fibroblasts. Masses of hemosiderin were detected outside the cells and in the macrophages, endothelial cells, and pericytes. Intracytoplasmatic crystalloid inclusions similar to those found in fetal endothelium and hemangiomas were observed in a few endothelial cells. These findings are different from those of previously reported cases of pseudo-Kaposi's sarcoma and may be helpful in distinguishing Kaposi's sarcoma from BSS. The role of immunodeficiency in the onset of BSS is discussed.
    Materialart: Digitale Medien
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  • 24
    ISSN: 1432-0428
    Schlagwort(e): Islet amyloid polypeptide ; Pancreatic islets ; B cells ; Ultrastructure ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Islet amyloid polypeptide is a novel 37 amino-acid-residues polypeptide which has been isolated from amyloid deposits in an insulinoma, and in human and cat islets of Langerhans. The molecule has 46% homology with the calcitonin gene-related peptide. Light microscopy examination of the pancreas shows that islet amyloid polypeptide immunoreactivity is restricted to the islet B cells. The present study utilized a rabbit antiserum against a synthetic peptide corresponding to positions 20–29 of islet amyloid polypeptide, a sequence without any amino-acid identity with calcitonin gene-related peptide. By applying the immunogold technique at the ultrastructural level, it was shown that both insulin and islet amyloid polypeptide immunoreactivity occurs in the central granular core of the human B cell secretory granules, while the A cells remain unlabelled. The demonstration that islet amyloid polypeptide is a granular protein of the B cells may indicate that it is released together with insulin. Further studies are necessary to evaluate the functional role of islet amyloid polypeptide.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 198 (1989), S. 92-102 
    ISSN: 1432-041X
    Schlagwort(e): Vitellogenesis ; Xenopus oocyte ; Yolk-platelet membrane ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The yolk platelets ofXenopus laevis have been studied by thin-section and freeze-fracture electron microscopy to characterize the boundary membrane during yolk formation. Throughout vitellogenesis, large yolk platelets are in close contact with smaller nascent yolk organelles. Two types of primordial yolk platelets (I and II) have been discriminated. After membrane fusion these precursors can be completely incorporated into the main body of existing platelets, numerous yolk crystals then merge and form one uniformly stratified core. Lipid droplets are tightly attached to the membrane at all developmental stages of yolk platelets. A direct connection of endoplasmic reticulum to the membranes of yolk platelets was not observed. On freezeetching replicas, yolk-platelet membranes present fracture faces with intramembranous particles (IMP) of various sizes and a heterogeneous distribution of approximately 200–600 IMP/μm2 at the E face, and 1200–2100 IMP/μm2 at the P face. Again, this presentation of the membrane exhibits neither anastomoses to the endoplasmic reticulum, nor caveolae that exclude the uptake of yolk-containing vesicles into these yolk organelles. Proteinaceous yolk platelets tend to fracture along their periphery through the superficial layers.
    Materialart: Digitale Medien
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  • 26
    ISSN: 1432-1106
    Schlagwort(e): Calcitonin gene-related peptide (CGRP) ; Bed nucleus of the stria terminalis ; Central nucleus of the amygdala ; Ultrastructure ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Light and electron microscopic analysis of calcitonin gene-related peptide (CGRP)-like immunoreactive (LI) terminals in the bed nucleus of the stria terminalis (BST) and the central nucleus of the amygdala (Ce) was carried out using the peroxidase-antiperoxidase method. CGRP-LI fibers were densely distributed in the dorsal subdivision of the lateral BST (BSTL) and the lateral and lateral capsular subdivisions of the Ce, where the CGRP-LI terminals formed symmetrical and asymmetrical axo-dendritic, and symmetrical axosomatic synapses. One of the most characteristic features of the CGRP-LI terminals was the presence of large, long boutons, each of which surrounded a cell soma and made many synaptic contacts. These findings suggest that CGRP exerts a significant influence on neurons in the BSTL and Ce.
    Materialart: Digitale Medien
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 76 (1989), S. 12-20 
    ISSN: 1432-1106
    Schlagwort(e): Distribution ; Ultrastructure ; Biopsy ; Catecholamines ; Interneurons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In freshly fixed biopsies of human cerebral cortex obtained at surgery, immunocytochemical staining with antibodies against tyrosine hydroxylase (the rate limiting biosynthetic enzyme for catecholamines) revealed, in addition to a dense axonal plexus, a population of immunoreactive cell bodies. The neuronal nature of these cells was ascertained by: i) the presence of a rich rough endoplasmic reticulum in the cell body and of synapses on the cell body and dendrites, and ii) the demonstration of the lack of reactivity with the astroglial marker, glial fibrillary acidic protein, in the tyrosine hydroxylase-immunoreactive cells. The tyrosine hydroxylase-immunoreactive neurons were found in all areas of cortex sampled, and were located almost exclusively in the infragranular layers. Most tyrosine hydroxylase-immunoreactive cells were bipolar and were vertically oriented, but a few had a multipolar or horizontal dendritic arbor. The dendrites of these cells were varicose and aspiny, and the axons were very thin. Tyrosine hydroxylase-immunoreactive neurons were reported to be present transiently in the developing mammalian cerebral cortex and only recently in cerebral cortex of mature mammalian brains. Internuncial neurons in the human cerebral cortex containing a catecholamine synthesizing enzyme would be significant, in particular considering that catecholamines are likely to be involved in some major mental disorders.
    Materialart: Digitale Medien
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Sexual plant reproduction 2 (1989), S. 154-166 
    ISSN: 1432-2145
    Schlagwort(e): Helianthus annuus ; Unfertilized ovule culture ; Parthenogenesis ; Ultrastructure ; Proembryo
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Electron microscope studies have been conducted on the parthenogenesis induced by in vitro culture of unfertilized ovules of sunflower (Helianthus annuus). In comparison with the state of the egg prior to inoculation, some eggs 5 days after culture show striking ultrastructural changes, which include, among others, nuclear migration, an increase in the number and activity of the organelles, a loss of polarity and wall formation at the chalazal end of the cell. Most of these changes are similar to those that occur normally in the zygote, indicating that parthenogenic development has been triggered in these eggs. Such eggs have been termed activated and are presumed to be capable of undergoing parthenogenesis. The parthenogenic proembryos which result share some features in common with zygotic proembryos. In addition, some parthenogenic proembryos exhibit unique properties not found in zygotic proembryos. These include embryos that consist of two parts differing markedly in density, an inversion of polarity, the frequent occurrence of autophagic vacuoles, the thickening of cell walls, a centripetal growth mode of wall formation, the appearance of an incomplete cell wall, free nuclear division, amitosis and degeneration. We believe that these ultrastructural peculiarities are the effects of in vitro culture.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Sexual plant reproduction 2 (1989), S. 193-198 
    ISSN: 1432-2145
    Schlagwort(e): Polymorphism ; Ultrastructure ; Pollen grains ; Canna indica L ; Tannin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Our investigations on Canna indica L. indicate that the pollen of this species is polymorphic: there are two types of pollen — a larger type and a comparatively smaller type. Transmission electron microscopy (TEM) revealed the presence of small vacuoles containing tannic substances in the generative cell (GC) of the larger grains: the GC of the mature grain contained a higher quantity of tannins than the GC of the immature grain. Mitochondria, lipid bodies, rough endoplasmic reticulum (RER) and microtubular bundles were present in the cytoplasm of the GC. Numerous mitochondria, lipid bodies and plastids were also present in the vegetative cell (VC), with the mitochondria clustered around the vegetative nucleus. The plastids were observed to be associated with the RER cisterns. During the maturation process, the number of starch grains contained in the plastids decreased.
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  • 30
    ISSN: 1432-072X
    Schlagwort(e): Methanobacterium formicicum ; Formate dehydrogenase ; F420-hydrogenase ; Immunogold ; Ultrastructure ; Methanogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The ultrastructural locations of the coenzyme F420-reducing formate dehydrogenase and coenzyme F420-reducing hydrogenase of Methanobacterium formicicum were determined using immunogold labeling of thin-sectioned, Lowicryl-embedded cells. Both enzymes were located predominantly at the cell membrane. Whole cells displayed minimal F420-dependent formate dehydrogenase activity or F420-dependent hydrogenase activity, and little activity was released upon osmotic shock treatment, suggesting that these enzymes are not soluble periplasmic proteins. Analysis of the deduced amino acid sequences of the formate dehydrogenase subunits revealed no hydrophobic regions that could qualify as putative membrane-spanning domains.
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  • 31
    ISSN: 1432-072X
    Schlagwort(e): Gallionella ferruginea ; Thiobacillus ferrooxidans ; Iron bacteria ; Chemolithoautotrophy ; Ultrastructure ; Freeze-etching ; Cell wall organization ; Intracytoplasmic membranes ; Carboxysomes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract By using sodium thioglycolate to dissolve the high amount of excreted stalk material in axenic cultures of the chemolithoautotrophic iron bacterium Gallionella ferruginea, the ultrastructure of Gallionella cells from pure cell suspensions could be studied without any loss of viability or disturbance by dense ferric stalk fibers, and compared with Thiobacillus ferrooxidans, also grown chemolithoautotrophically with ferrous iron as energy source. Both organisms were chemically fixed or freeze-etched. Particular structural differences between these iron-bacteria could be ascertained. G. ferruginea possesses intracytoplasmic membranes and soluble d-ribulose-1,5-bisphosphate-carboxylase, whereas T. ferrooxidans contains carboxysomes but no intracytoplasmic membranes; Gallionella forms poly-β-hydroxybutyrate and glycogen as storage material; T. ferrooxidans produces only glycogen. Both organisms also differ from each other with respect to the freeze fracture behaviour of the cell envelope layers. Whereas the cells of T. ferrooxidans exhibit a characteristic double cleavage, exposing the plasmic fracture face and exoplasmic fracture face of the outer membrane and cytoplasmic membrane, the exceptionally thin multilayered cell envelope of G. ferruginea revealed a particularly intimate association between the layers, resulting in a visualisation of the supramolecular organisation of only the inner fracture face of the cytoplasmic membrane. The results are discussed predominantly in relation to the extremely distinct environments of both organisms.
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  • 32
    ISSN: 1432-072X
    Schlagwort(e): Thiothrix sp. ; Beggiatoa sp. ; Sulfideoxidizing ; Polyunsaturated ; Fatty acids ; Inclusions ; Sheath ; Southern California ; Ultrastructure ; Sulfur
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Microscopic examination of the whitish mat that covered the substrata around subtidal hydrothermal vents at White Point in southern California revealed a “Thiothrix-like” bacterium containing sulfur inclusions as the dominant filamentous form in this microbial community. The matlike appearance developed as a result of the closely-packed manner inwhich the basal ends of the filaments were anchored to the substrate. The dominant phospholipid fatty acids of these filaments (16:0, 16:1w7c, 18:0, 18:1w7c) were similar to those recovered from a sample of Beggiatoa isolated from a spring in Florida. Filaments from both sources contained small quantities of C18 and C20 polyunsaturated fatty acids, as well. A larger but less abundant sheathless, filamentous form, which also contained sulfur inclusions and displayed a cell wall structure similar to a previously described Thioploca strain, also colonized the substrata around the subtidal mat. The preservation methods used in the preparation of thin-sections of the subtidal mat material were found to be inadequate for defining some key cellular structures of the large filaments. Nevertheless, the results demonstrate that the filamentous bacteria comprising the microbial mat in the vicinity of the subtidal vents exhibit some of the features of the free-living filamentous microorganisms found in deep-water hydrothermal areas.
    Materialart: Digitale Medien
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  • 33
    ISSN: 1432-2013
    Schlagwort(e): Exercise ; Heart ; Mitochondria ; Oxygen uptake ; Respiration ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The relationship between maximal oxygen consumption rate ( $$\dot V{\text{O}}_{{\text{2max}}}$$ ) and mitochondrial content of skeletal muscles was examined in horses and steers (n=3 each). Samples of the heart left ventricle, diaphragm,m. vastus medialis, m. semitendinosus, m. cutaneous thoracicus andm. masseter, as well as samples of muscles collected in a whole-body sampling procedure, were analyzed by electron microscopy. $$\dot V{\text{O}}_{{\text{2max}}}$$ per kilogram body mass was 2.7× greater in horses than steers. This higher $$\dot V{\text{O}}_{{\text{2max}}}$$ was in proportion to the higher total volume of mitochondria in horse versus steer muscle when analyzed from the whole-body samples and from the locomotor muscle samples. In non-locomotor muscles, total mitochondrial volume was greater in horses than steers, but not in proportion to their differences in $$\dot V{\text{O}}_{{\text{2max}}}$$ . The $$\dot V{\text{O}}_{{\text{2max}}}$$ of the mitochondria was estimated to be close to 4.5 ml O2·ml−1 mitochondria in both species. It is concluded that in a comparison of a highly aerobic to a less aerobic mammalian species of similar body size, a higher oxidative potential may be found in all muscles of the more aerobic species. This greater oxidative potential is achieved by a greater total volume of skeletal muscle mitochondria.
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  • 34
    ISSN: 1432-0878
    Schlagwort(e): Corpora allata ; Ultrastructure ; Precocenes ; Juvenile hormone ; Blattella germanica (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Ultrastructural studies on corpora allata (CA) from different stages during the first gonadotropic cycle of the cockroach Blattella germanica have shown well defined changes which have a correspondence with oocyte length, CA volume and juvenile hormone (JH) biosynthesis. The most significant variations concern the mitochondria and the endoplasmic reticulum. Topically applied precocene II (P II) at a dose of 200 ⧎g induced a transient arrest of CA function, although cytotoxic effects were occasionally observed. When CA were maintained in vitro with 10-3 M of P II, a relationship between the time of treatment (3, 6 or 9 h) and the intensity of the effects was apparent. The 9-h treatment led to an irreversible inhibition of JH production which parallels the severe damages observed in the CA (membrane lysis, nuclear pyknosis, vacuolization). Equivalent studies performed with the chroman derivative 3,4-dihydroprecocene II (DHP II) showed that it is less active than P II. Only treatments as severe as 12 h of incubation with a 10-3 M concentration elicited cytotoxic effects which could be due to radical species involved in the in situ oxidative bioactivation of DHP II. Thus, this compound could be regarded as a new type of pro-allatocidin.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 258 (1989), S. 203-210 
    ISSN: 1432-0878
    Schlagwort(e): Epididymis ; Histology ; Ultrastructure ; Antechinus stuartii (Marsupialia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ductus epididymidis of the marsupial mouse Antechinus stuartii was divided into caput, corpus, and caudal regions using several constant morphological landmarks. Tubule diameter and epithelial height increased gradually from caput to cauda. In contrast, the surface area of the lumen of the ductus epididymidis increased to a maximum in the distal caput region, but decreased markedly in the distal cauda in association with characteristic changes in lumen shape (from circular to slit-shaped) and epithelial height. Epithelial cells of the ductus epididymidis were generally similar in structure to those described in other mammalian species. Principal and basal cells were common throughout the epithelium. Clear and mitochondria-rich cells were also identified, but occurred less frequently. Regional variations in cell ultrastructure were observed only in principal cells. Numerous vesicular inclusions occurred in the apical cytoplasm of cells in caput segments, membrane-bounded, electron-dense bodies were common in distal corpus regions, and a brush border of microvilli characterized the luminal surface of principal cells in caudal segments. Sperm index increased in the proximal caput, declined to basal levels in the distal caput and proximal corpus, and then increased to a maximum in segment 9 of the distal corpus and remained at about this level throughout the cauda epididymidis. Nuclear rotation, loss of cytoplasmic droplets, and other sperm maturational changes were observed along the epididymis. Discarded cytoplasmic droplets collected in large masses interspersed between aggregates of spermatozoa throughout the distal regions of the duct. There was no evidence of phagocytosis by principal cells of cytoplasmic droplets. The epididymis of A. stuartii differs from that of other mammals. The unusual caudal region, which has little storage capacity for sperm, is an unusual adaptation in a species in which the male is known to be polygamous.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 258 (1989), S. 247-257 
    ISSN: 1432-0878
    Schlagwort(e): Zinc ; Timm method ; Ultrastructure ; Synapses ; Avian brain ; Domestic fowl
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The brain of young domestic chicks was investigated using a Timm sulfide silver method. Serial Vibratome sections were analyzed under the light microscope, and the localization of zinc-positive structures in selected areas was determined at the ultrastructural level. Both strong and differential staining was visible in the avian telencephalon whereas most subtelencephalic structures showed a pale reaction. The highest staining intensity was found in the nonprimary sensory regions of the telencephalon such as the hyperstriatum dorsale, hyperstriatum ventrale, hippocampus, palaeostriatum augmentatum, lobus parolfactorius and caudal parts of neostriatum. There was an overall gradient of staining intensity in neostriatal areas from rostral to caudal with the heaviest zinc deposits in the caudal neostriatum. Primary sensory projection areas, such as the ectostriatum (visual), hyperstriatum intercalatum superius (visual), nucleus basalis (beak representation), the input layer L2 of the auditory field L and the somatosensory area rostral to field L were selectively left unstained. Fiber tracts throughout the brain were free of zinc deposits except for glial cells. In electron micrographs of stained regions, silver grains were localized in some presynaptic boutons of asymmetric synapses (Gray type I), within the cytoplasm of neuronal somata and sporadically in the nucleus. The possible involvement of zinc in synaptic transmission and other processes is discussed.
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  • 37
    ISSN: 1432-0878
    Schlagwort(e): Enterochromaffin-like cells ; Ultrastructure ; Hypertrophy ; Hypergastrinaemia ; Gastrin infusion ; Omeprazole ; Rat (Sprague Dawley) ; Syrian hamster ; Guinea pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The present report describes the ultrastructure of the enterochromaffin-like (ECL) cells in the stomach of the rat, hamster and guinea pig, and the ultrastructural consequences of long-term hypergastrinaemia evoked either by continuous infusion of synthetic human (Leu15)-gastrin-17 for 4 weeks (rats) or by daily treatment with large doses of the antisecretory agent omeprazole for 2–10 weeks (rats, hamsters and guinea pigs). As a result, the ECL cells increased greatly in size (maximal effect after 2 weeks of omeprazole treatment, no further gain in size after 4 or 10 weeks). Also the endoplasmic reticulum and Golgi area were enlarged. The most conspicuous feature of the ECL cells is the cytoplasmic vesicles, which are of varying size and either devoid of a dense core or with a small, often eccentrically located dense core. The vesicles probably represent the main storage site of the secretory products of the ECL cell. In addition, the cytoplasm contains granules, which differ from the vesicles in that they possess a more or less electron-dense core, surrounded by a narrow halo. The size of the vesicles ranged from small to very large, while the granules were uniformly small. Many vesicles were seen to lie very close together, some displaying an irregular outline (vacuole-like vesicles), at times giving the impression that they were undergoing fusion. The profile size (median value) of the vesicles was unaffected by gastrin infusion for 4 weeks. However, there was a tendency to a relative increase in the number of very small vesicles. In contrast, the vesicles became larger during the omeprazole treatment. Also, the number of vesicles that seemed to be engaged in fusion increased after omeprazole treatment but not after gastrin infusion. The observations support the view that ECL cells are influenced by gastrin. The effects of gastrin infusion and of omeprazole treatment on ECL cell ultrastructure were not completely identical. It cannot be excluded that the omeprazole-evoked achlorhydria evokes effects unrelated to those of hypergastrinaemia on the ECL cells, or that endogenous gastrins may evoke effects that are in some ways distinct from those of synthetic human (Leu15)-gastrin-17. Alternatively, the additional effects seen after long-term omeprazole treatment may reflect simply the duration of the hypergastrinaemic stimulus.
    Materialart: Digitale Medien
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 256 (1989), S. 303-307 
    ISSN: 1432-0878
    Schlagwort(e): Arachnoid cells ; Tight and gap junctions ; Cold injury ; Ultrastructure ; Freeze-fracture technique ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The junctional complexes of cells in the outer arachnoid layer overlying the cerebral cortex of 2-week-old rats were examined with freeze-fracture electron microscopy up to 60 min after transcranial cold injury to the dorsal surface of the brain. Within 30 min after injury, areas of gap and tight junctions with morphological features characteristic of junction formation and/or junction disruption were found scattered among normal junctional complexes in some arachnoid cells. Within 60 min after injury, tight junctions with features typical of less leaky zonulae occludentes were present in all arachnoid cells examined. These morphological features include increases in the number of tight junctional strands and the number of strand-to-strand anatomoses. Gap junctions were interspersed among the tight junctional strands, and many were completely encircled by the strands. The increase in the number and complexity of the tight junctional strands in response to brain injury may be the morphological basis for the maintenance of the cerebrospinal fluid-blood dural barrier.
    Materialart: Digitale Medien
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  • 39
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex ; Differentiation ; Tissue culture ; Steroids ; Ultrastructure ; Lipoproteins ; Rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary We studied the effects of lipoprotein-derived cholesterol on the ACTH-induced differentiation of cultured fetal rat adrenocortical cells. For this purpose human plasma high-density lipoprotein3 (HDL3) or low-density lipoprotein (LDL) was added to culture media devoid of cholesterol, and thereafter the morphological changes in cells were monitored and the amounts of steroids synthesized were measured. It could be demonstrated that, ultrastructurally, upon ACTH-stimulation the adrenocortical cells differentiated into fasciculata-like cells even in the absence of lipoproteins in the culture medium. The addition of either HDL3 or LDL caused an increase in the number and size of cytoplasmic lipid droplets suggesting uptake and deposition of lipoprotein-derived cholesterol into the differentiating cells. The amount of steroids secreted from cells differentiating in media devoid of cholesterol was only half that observed in cells differentiating in serum-supplemented medium. Addition of either HDL3 or LDL increased the ACTH-stimulated steroid synthesis to the levels observed in serum-supplemented medium. This study demonstrates that both HDL3 and LDL are able to provide cholesterol for steroid synthesis accompanying the ACTH-induced differentiation of fetal rat adrenocortical cells.
    Materialart: Digitale Medien
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 255 (1989), S. 405-410 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland, pars intermedia ; Bromocriptine ; Secretory granules ; Golgi apparatus ; Ultrastructure ; Rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The morphological effect of chronic synthetic and secretory inhibition of the intermediate lobe of the rat pituitary induced by bromocriptine treatment was studied using morphometric techniques in combination with electron microscopy. On the basis of granule diameters, a heterogeneous cell population was shown in the normal intermediate lobe. Bromocriptine treatment did not induce any change in the volume fraction, number or location of electron-dense secretory granules. Instead, there was a shift toward a more homogeneous cell population containing smaller granules, the mean granule volume being reduced by ∼30%. The volume fraction of electron-lucent granules or vacuoles was markedly reduced, indicating a functional significance of these organelles. The volume of the Golgi apparatus was not significantly altered, but the number of condensing granules within the Golgi area was reduced. The volume of the intermediate lobe was decreased, apparently due to a decrease in the mean cell volume.
    Materialart: Digitale Medien
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  • 41
    ISSN: 1432-0878
    Schlagwort(e): Endostyle ; Peroxidase cytochemistry ; Autora diography ; Ultrastructure ; Oikopleura albicans, Oikopleura longicauda (Appendicularia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Oikopleura albicans and O. longicauda belong to the two subgenera Vexillaria and Coecaria, respectively. The morphology and ultrastructure of their endostyles were investigated with conventional microscopic procedures as well as with DAB cytochemistry and 125I autoradiography at both light- and electron-microscopic levels. As expected, the general morphology of these endostyles is similar to all hitherto examined endostyles. They possess a ventral portion consisting of alternating glandular and ciliated cell zones, probably serving food capture, and a dorsal region, the corridor. Autoradiographic grains were found mainly in the corridor lumen associated with the apical surface of the two central rows of corridor cells. The same cells also gave strong positive reactions for peroxidase, the iodinating enzyme. Peroxidase activity was found in the apical plasma membrane as well as in the nuclear envelope, rough endoplasmic reticulum, Golgi area and cytoplasmic vesicles. Definitive conclusions concerning an apical uptake and subsequent release into the body fluid of iodinated material could not be made from the present experiments. Our investigations indicate that the two central rows of corridor cells in both subgenera of oikopleurids constitute the protothyroid region, possibly homologous to the vertebrate thyroid gland.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 257 (1989), S. 207-216 
    ISSN: 1432-0878
    Schlagwort(e): Morphogenesis ; Meninges ; Mesenchyme ; Ultrastructure ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The meninges of albino Wistar rat embryos, aged between the 11th embryonic day (ED) and birth, were sectioned using a specially constructed device. This technique permits optimal microanatomical preservation of all tissues covering the convexity of the brain: skin, muscle, cartilage or bone, and the meninges. At ED11, the zone situated between the epidermis and the brain is occupied by a mesenchymal network. At ED12, part of this delicate network develops as a dense outer cellular layer, while the remainder retains its reticular appearance, thus forming an inner layer (the future meningeal tissue). At ED13, the dura mater starts to differentiate. At ED14, the bony anlage of the skull can be identified, and along with the proceeding maturation of dura mater some fibrillar structures resembling skeletal muscle fibers appear in the developing arachnoid space. At ED15–17, a primitive interface zone — dura mater/ arachnoid — is formed, comprised by an outer electronlucent and an inner electron-dense layer marking the outer aspect of the arachnoidal space. At ED18–19, the innermost cellular row of the inner durai layer transforms into neurothelium, which is separated from the darker arachnoidal cells by an electron-dense band. The arachnoidal trabecular zone with the leptomeningeal cells is formed at ED19. By the end of the prenatal period (ED20–21), its innermost part organizes into an inner arachnoidal layer and an outer and inner pial layer. The results from this study indicate (i) that dura mater and leptomeninges develop from an embryonic network of connective tissue-forming cells, and (ii) that the formation of cerebrospinal fluid (CSF)-containing spaces accompanies the differentiation of the meningeal cellular layers.
    Materialart: Digitale Medien
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  • 43
    ISSN: 1432-0878
    Schlagwort(e): Serotonin-containing cells ; Urophysis ; Spinal Cord ; Ultrastructure ; Leptomeninges ; Poecilia latipinna (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The caudal neurosecretory complex of poeciliids has previously been shown to be innervated by extranuclear and intrinsic serotonergic projections. In the present study, immunohistochemical techniques were used to characterize fibers originating from serotonin neurons intrinsic to the caudal spinal cord. Bipolar and multipolar neurons were oriented ventromedially, and contained numerous large granular vesicles. Three types of serotonergic fibers were distinguished based on their distribution and morphology. Intrinsic Type-A fibers branched into varicose segments near the ventrolateral surface of the spinal cord and contacted the basal lamina beneath the leptomeninges. Type-B fibers coursed longitudinally to enter the urophysis, where they diverged and terminated around fenestrated capillaries. Labelled vesicles in Type-A and Type-B terminals were the same size as those in labelled cells and in unlabelled neurosecretory terminals in the urophysis. Type-C small varicose fibers branched within the neuropil of the caudal neurosecretory complex. Serotonin may be secreted into the submeningeal cerebrospinal fluid, the urophysis, and the caudal vein by Type-A and Type-B fibers, whereas, Type-C fibers may be processes of serotonergic interneurons in the neuroendocrine nucleus. The possibility that urotensins I and II or arginine vasotocin were colocalized in the processes of the intrinsic serotonin neurons was investigated immunohistochemically. The negative results of these experiments suggest that serotonin-containing neurons may represent a neurochemically distinct subpopulation in the caudal neurosecretory complex.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 255 (1989), S. 641-644 
    ISSN: 1432-0878
    Schlagwort(e): Insect muscle ; Denervation ; Ultrastructure ; Development, ontogenetic ; Neoconocephalus robustus (Insecto)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The singing muscles of the katydid Neoconocephalus robustus develop adult ultrastructure late in the last nymphal instar and during the first few days of adult life. The ultrastructural changes during early adulthood were not affected by unilateral axotomy shortly after the adult molt. Both denervated and innervated muscles developed adult proportions of mitochondria, myofibril, and sarcoplasmic reticulum and transverse tubules.
    Materialart: Digitale Medien
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  • 45
    ISSN: 1432-0878
    Schlagwort(e): Zona pellucida ; Ovarian follicles ; Atresia ; Ultrastructure ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The present study provides further details on the fine-structural three-dimensional architecture of the zona pellucida (ZP) in growing and atretic follicles of mice by use of ruthenium red in combination with the detergents Triton X100 and saponin. These detergents were used for extraction of the “soluble” fraction of the zonal proteins in an attempt to expose the “structural” zonal glycoproteins, which in turn can be viewed as minute three-dimensional networks upon transmission- and scanning electron-microscopic examination. By use of these methods, the ZP of growing follicles appeared to be formed by interconnected filaments which also bind to globular structures building up a three-dimensional lattice. In contrast, the ZP of stage I as well as other (II and III) stages of atretic follicles showed a structure characterized by the presence of closely packed granules connected with short filaments to form a close-mesh reticulum. This structural change of the ZP, which in the present study is also associated with the disappearance of “gap junctions” within the granulosa and cumulus cell population, might represent one of the early events involved in the onset of atresia. These changes, most probably depending on an altered secretory activity of both oocytes and follicle cells, might lead to a degradation of the ZP network structure and to its subsequent increased density (condensation). All these morphodynamic events eventually contribute to a sequestration of the oocyte in the early stage of atresia.
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 257 (1989), S. 405-414 
    ISSN: 1432-0878
    Schlagwort(e): Mollusc ; Ultrastructure ; Musculature ; Hydroskeleton ; Retraction reflex ; Clione limacina (Mollusca)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Wing (parapodial) retraction in the pteropod mollusc Clione limacina is a reflex triggered by tactile stimulation. Light and transmission electron microscopy revealed three groups of smooth muscles in the wing hemocoel that participate in retraction movements: transverse, longitudinal, and dorsoventral. Among these, two subtypes of muscle cells were identified. The first (type A) appears in all three groups and forms a well-organized lattice-like structure. The second (type B) is the major component of transverse muscles and runs in one direction only. Quantitative ultrastructural comparisons of dimensions, abundance, and organization of dense bodies, thick and thin filaments, membrane invaginations, sarcoplasmic reticulum, and mitochondria suggest that type A cells are able to contract and relax more quickly with less endurance whereas type B cells are capable of generating stronger contractions with more endurance and slower relaxation speed. Furthermore, type A cells have a unique pattern of thick filament organization, here referred to as pseudosarcomeres. The roles played by the different cell types in wing retraction are discussed.
    Materialart: Digitale Medien
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  • 47
    ISSN: 1432-0878
    Schlagwort(e): Hippocampus ; Mossy fibers ; Picrotoxin ; Ultrastructure ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Ultrastructural changes in hippocampal granule cells, mossy fibers and mossy fiber boutons were examined following the administration of picrotoxin in adult rats. Generalized seizures occurred within 5–10 min after the intraperitoneal injection of picrotoxin. The electron-microscopic examination of hippocampal tissues from rats that had been perfused with fixative during the seizure revealed that the large dense-core vesicles increased in number and accumulated on the presynaptic membranes of mossy fiber boutons; some of these vesicles appeared to be fused with the membranes, and omega-shaped exocytotic profiles were frequently seen. Furthermore, greatly increased numbers of coated vesicles (60–90 nm in diameter) were observed on the maturing faces of Golgi fields of granule cells. Thus, our study not only indicates an increased incidence of exocytosis of large dense-core vesicles during picrotoxin-induced seizures, but also suggests that these vesicles are replaced in excess from the perikaryon of the granule cell.
    Materialart: Digitale Medien
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  • 48
    ISSN: 1615-6102
    Schlagwort(e): Adhesion ; Carbohydrates ; Exocytosis ; K-bodies ; Lectins ; Saprolegnia ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Electron and fluorescence microscopy were used to identify organelles involved in attachment of secondary zoospores ofSaprolegnia ferax as they were transformed into secondary cysts. When secondary zoospores were exposed to 1.0% peptone in the absence or presence of a substrate, they began to encyst. If substrates were present when encystment was induced, the groove surface of the secondary zoospores adhered to them. The first event in attachment was secretion of contents of the kinetosome-associated organelle (K-body), which was typically oriented with the tubule-filled cavity positioned toward the cell surface of the groove region in the zoospore. The tubules which contained carbohydrates became coarsely granular, the matrix became more fibrous, and the shell remained along the membrane concavity that was formed as the K-body fused with the plasma membrane. Five minutes later, a cyst coat appeared, and cysts were not readily dislodged from a substrate. The concavity was no longer found, presumably because it had evaginated; but a layered pad of adhesion material was between the cyst coat and substrate. The layers of the adhesion pad corresponded to the structure of the matrix of K-bodies. As with the tubules of the K-body, the coarsely granular portion at the edge of the pad stained for carbohydrates. Similarly, the lectins WGA and GS-II labeled with fluorescein stained the rim of the adhesion pad on cysts, indicating the presence of glycoconjugates containing N-acetylglucosamines. Because globular areas near the kinetosomes and groove of zoospores (where K-bodies were located) also bound WGA and GS-II, K-bodies contained the same carbohydrates as the adhesion pad. We conclude that K-bodies function in the attachment of encysting zoospores to substrates as the cell differentiates. The tubular portion of the K-body matrix contains carbohydrates which might assist in the adhesion process.
    Materialart: Digitale Medien
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 150 (1989), S. 83-95 
    ISSN: 1615-6102
    Schlagwort(e): Drosophila melanogaster embryo ; Cellularization ; Cleavage furrow ; Ultrastructure ; Cytoskeleton ; Mitosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The distribution and arrangement of cytoskeletal components in the early embryo ofDrosophila melanogaster were examined by thin-section electron microscopy to elucidate their involvement in the formation of the cellular blastoderm, a process called cellularization. During the final nuclear division in the cortex of the syncytial blastoderm bundles of astral microtubules were closely associated with the surface plasma membrane along the midline where a new gutter was initiated. Thus the new gutter together with the pre-formed ones compartmentalized the embryo surface to reflect underlying individual daughter nuclei. Subsequently such gutters became deeper by further invagination of the plasma membrane between adjacent nuclei to form so-called cleavage furrows. Nuclei simultaneously elongated in the direction perpendicular to the embryo surface and numerous microtubules from the centrosomes ran longitudinally between the nucleus and the cleavage furrow. Microtubules often appeared to be in close association with the nuclear envelope and the cleavage furrow membrane. The plasma membrane at the advancing tip of the furrow was always undercoated with an electron-dense layer, which could be shown to be mainly composed of 5–6 nm microfilaments. These microfilaments were decorated with H-meromyosin to be identified as actin filaments. As cleavage proceeded, each nucleus with its perikaryon became demarcated by the furrow membrane, which then extended laterally to constrict the cytoplasmic connection between each newly forming cell and the central yolk region. The cytoplasmic strand thus formed possessed a prominent circular bundle of microfilaments which were also decorated with H-meromyosin and bidirectionally arranged, similar in structure to the contractile ring in cytokinesis. These observations strongly suggest that both microtubules and actin filaments play a crucial role in cellularization ofDrosophila embryos.
    Materialart: Digitale Medien
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  • 50
    ISSN: 1615-6102
    Schlagwort(e): Plectonema boryanum ; Cyanobacteria ; Ultrastructure ; Nitrogen fixation ; Nitrogen starvation ; Immunogold localization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructure of fructose-supplemented and unsupplemented nitrogen-fixing (fix +) and nonfixing (fix −)Plectonema boryanum UTEX 581 cells was examined by transmission electron microscopy. The most prominent structural differences included the arrangement and morphology of the thylakoids and alterations in the appearance of the interthylakoidal spaces. These ultrastructural differences, together with other observations such as glycogen content and presence of nitrogenase (using acetylene reduction assay and immunogold localization), readily distinguished nonfixingP. boryanum from nitrogen-fixing cells.
    Materialart: Digitale Medien
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  • 51
    ISSN: 1615-6102
    Schlagwort(e): Apiaceae ; Apium nodiflorum ; Endoplasmic reticulum ; Pollen grain ; Polysaccharide particles ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructural events in 3-cellular pollen grains ofApium nodiflorum L. are investigated during pollen maturation. Three distinct developmental stages are distinguished from the formation of sperm cells up to anthesis, whereby the rough endoplasmic reticulum (RER) is mainly involved. The most conspicious form is the highly dilated RER in the vegetative cytoplasm of the youngest pollen grains, which changes to vesicular RER in the following stage. In mature pollen grains the RER has a narrow cisternal configuration and often forms stacks. Pollen activation is preceded by the accumulation of polysaccharide particles.
    Materialart: Digitale Medien
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 151 (1989), S. 47-56 
    ISSN: 1615-6102
    Schlagwort(e): Scenedesmus ; Fuel oil ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Characteristic changes in the ultrastructure of the green algaScenedesmus armatus, grown in batch culture in the presence of aqueous fuel-oil extract (AFOE) have been observed. The changes affected mainly chloroplasts and mitochondria. The regular arrangement of the thylakoid stacks became distorted and the whole chloroplast lobed. Plastoglobules were more numerous in the treated cells than in the controls, especially after long-term exposure to AFOE. The mitochondrial matrix cells exposed to AFOE were more electron-translucent. An increase in the number of small mitochondrial profiles was observed after prolonged treatment with AFOE. The number and size of osmophilic bodies increased markedly in the cytoplasm of the treated cells. The cytochemical reaction of these bodies with Sudan black B indicated their lipid composition. Plasmalemma invagination into the cytoplasm and vacuoles, cytoplasmic “layers”, and an increase in size of the vacuolar compartment were observed in cells exposed to AFOE for a long time. The possibility that detoxification, involving microbody activity, may have occurred inScenedesmus is suggested.
    Materialart: Digitale Medien
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  • 53
    ISSN: 1615-6102
    Schlagwort(e): Bryophyte ; Notothylas ; Nuclear metamorphosis ; Phaeoceros ; Posterior mitochondrion ; Spermatogenesis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Ultrastructural observations reveal that the spermatozoids of the hornwortsNotothylas andPhaeoceros contain two mitochondria and not one as described previously. Mitochondrial ontogeny and nuclear metamorphosis during spermiogenesis in these plants differ from all other archegoniates. The discovery that the posterior region of the coiled nucleus (when viewed from the anterior aspect) lies to the left of the anterior, in striking contrast to the dextral coiling of the nucleus of spermatozoids of other embryophytes, underlines the isolated nature of the hornworts among land plants. As the blepharoplast develops, the numerous ovoid mitochondria initially present in the nascent spermatid fuse to form a single elongated organelle which is positioned subjacent to the MLS and extends down between the nucleus and plastid. At the onset of nuclear metamorphosis, the solitary mitochondrion has separated into a larger anterior mitochondrion (AM) associated with the MLS and a much smaller posterior mitochondrion (PM) adjacent to the plastid. The PM retains its association with the plastid and both organelles migrate around the periphery of the cell as the spline MTs elongate. By contrast, in moss spermatids, where mitochondria undergo similar fusion and division, the AM is approximately the same size as the PM and the latter is never associated with the spline. As in other archegoniates, except mosses, spline elongation precedes nuclear metamorphosis in hornworts. Irregular strands of condensed chromatin compact basipetally to produce an elongated cylindrical nucleus which is narrower in its mid-region. During this process excess nucleoplasm moves rearward. It eventually overarches the inner surface of the plastid and entirely covers the PM.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 152 (1989), S. 14-21 
    ISSN: 1615-6102
    Schlagwort(e): Differentiation ; Heterochronic lysis ; Polarity ; Root protophloem sieve elements ; Triticum aestivum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Developing protophloem sieve elements in roots of wheat are arranged in single vertical files. In the last immature differentiating sieve element bearing ribosomes the proximal end of the cytoplasm displays a diluted appearance in contrast to the distal end where the cytoplasm exhibits a considerably increased electron density. Differences can also be observed in ribosome quantity, organelle ultrastructure and the time of initiation of cell component degradation, those at the proximal end disorganizing first, suggesting a nonsimultaneous disorganization of the cell components in the two areas. This phenomenon, termedheterochronic lysis, is presumably an expression of an existing polarity not detectable in younger stages, but it might also be the result of an asynchronous enzymatic activity.
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 153 (1989), S. 104-110 
    ISSN: 1615-6102
    Schlagwort(e): Nicotiana sylvestris ; Pollen tube growth ; Heat shock ; Ultrastructure ; Endoplasmic reticulum ; Mitochondria ; Golgi apparatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The effect of elevated temperatures on semivivo growth and ultrastructure of tobacco pollen tubes was investigated. Tube growth was decreased by about 50% at 35 °C, independent of the duration of treatment, and at 40 °C and above there was no growth of tubes. Heat treatment caused ultrastructural changes like accumulation of membranous materials, concentric stacking of rough endoplasmic reticulum, reduction in vesicle production by dictyosomes, increase in the fenestrated regions of the Golgi cisternae, swelling of mitochondrial saccules and increase in the electron density of the mitochondrial matrix. Furthermore, the dictyosomes of the treated tubes showed significant increase in the number of cisternae from 30 to 45 °C. The temperature induced changes were persistant at least for 24 h in 35 °C grown pollen tubes. The possible reasons for the tube growth inhibition are discussed on the basis of the ultrastructural alterations caused by elevated temperatures.
    Materialart: Digitale Medien
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    European journal of applied physiology 59 (1989), S. 239-242 
    ISSN: 1439-6327
    Schlagwort(e): Collagen fibre ; Achilles tendon ; Disuse ; Atrophy ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We examined the influence exerted, through disuse of the hindlimb, on the collagen fibres of the achilles tendon in rats. With disuse the body mass decreased by 28%, and the mass of soleus muscle decreased by 20%. A decrease in the surface area and diameter was observed in the experimental group when compared to the control group. A histogram of the collagen fibres showed a decrease of the thick fibres in the experimental group. The maximum surface area of collagen fibres in the experimental group was seen to be only 43% of that of the control group. These results showed a decrease in the thickness of the collagen fibres of the achilles tendon through disuse. This seemed to suggest that resistance to tension is decreased by disuse.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 164 (1989), S. 65-73 
    ISSN: 1615-6110
    Schlagwort(e): Algae ; Glaucocystophyceae ; Cyanoptyche gloeocystis f.dispersa ; Ultrastructure ; endocytobiosis ; cyanelles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cyanoptyche gloeocystis f.dispersa (Geitler)Starmach is a palmelloid colonial alga that contains prokaryotic blue-green endocytobionts (cyanelles) instead of chloroplasts. The periphery of the host cell shows a peculiar lacunae system with underlying microtubules. Vegetative cells possess two rudimentary flagella. Zoospores are dorsiventrally shaped with two heterokont and heterodynamic flagella which originate from a subapical depression. This depression can also be seen in vegetative cells. Both flagella possess non-tubular mastigonemes. Main reserve product is starch lying freely in the cytoplasm. Cyanelles, enclosed singly in a host vesicle, are provided with a remnant cell wall. Thylakoids are arranged concentrically. The central part of each cyanelle harbours its DNA and one large polyhedral body, probably a carboxysome.Cyanoptyche gloeocystis f.dispersa shares all taxonomically essential characters with the monadoidCyanophora, the palmelloidGloeochaete, and the coccoidGlaucocystis. All of them are members of the cyanelle-bearing small algal classGlaucocystophyceae. Members of this class serve as model organisms for the evolution of chloroplasts from cyanophycean ancestors.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 164 (1989), S. 197-208 
    ISSN: 1615-6110
    Schlagwort(e): Algae ; Chlorophyta ; Desmidiaceae ; Micrasterias ; Ultrastructure ; electron microscopy ; cell multiplication ; salt stress
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cells ofMicrasterias denticulata Bréb. were kept in nutrient solution of high osmolality (salt stress) for four weeks. In a special cell multiplication test it was established that cell division is gradually inhibited at increasing salt concentrations and totally arrested at the highest concentration (26 mosm/kg). “Recovery studies” proved that even cells from the highest concentration range start dividing immediately after being placed in aqua bidest. thus indicating the full reversibility of the inhibiting effect. — Cells of the highest concentration range show marked ultrastructural changes. Besides an enormous accumulation of starch and oil bodies and a condensed appearance of the ground plasma, a reduction of mitochondria, ER and the Golgi-system is found. The most striking effect occurs on the vacuolar system which appears extremely reduced and condensed. The cell wall is thickened by the formation of an additional cell wall layer with a “spongy” electron microscopical appearance. Through the cell wall many droplets of a probably fat-like substance are excreted. — In summary, salt stress induces growth-inhibited “akinete” cells in the sense ofFritsch; these can be reactivated by decreasing the salt concentration. The salt-induced “akinete state” seems to be an ecological adaption to unfavourable conditions rather than a degeneration of the cells.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 168 (1989), S. 195-219 
    ISSN: 1615-6110
    Schlagwort(e): Algae ; Chlorophyta ; Chlorophyceae ; Pleurastrophyceae ; Hydrodictyon ; Neochloris ; Pediastrum ; Sphaeroplea ; Ultrastructure ; flagellar apparatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nine species ofNeochloris can be divided into three groups on the basis of comparative ultrastructure of the flagellar apparatus, the cell wall and the pyrenoid of zoospores. In Group I,N. wimmeri andN. minuta, zoospores are thin-walled, pyrenoids are penetrated by stromal channels, and the basal bodies are in the clockwise absolute orientation and connected by the distal and two proximal fibers. In Group II,N. aquatica, N. vigenis, N. terrestris, N. pyenoidosa, andN. pseudostigmatica, zoospores are naked or covered by fuzzy material, pyrenoids are covered by a continuous starch sheath or invaginated by cytoplasmic channels, basal bodies are directly opposed, the distal fiber is differentiated into a ribbed structure at the central region, a striated microtubule-associated component (SMAC) is continuous between opposite two-membered rootlets and connected to the ribbed structure, proximal ends of basal bodies are covered by partial caps, each two-membered rootlet and a basal body are connected by a striated fiber to the X-membered rootlet associated with the opposite basal body, and the basal bodies, when oriented at wide angles, are joined at their proximal ends by core extensions. In Group III,N. pseudoalveolaris andN. cohaerens, zoospores are naked, pyrenoids are traversed by parallel thylakoids, basal bodies are in the counterclockwise absolute orientation and overlapped, and each X-membered rootlet is connected to the end of the opposite basal body by a terminal cap. It is suggested that the genusChlorococcopsis gen. nov. be erected for the Group I species. Group II, which includes the type species,N. aquatica, should be preserved asNeochloris. The group appears to be closely related to the coenobial generaPediastrum, Hydrodictyon, andSorastrum, and to have affinities with the coenocytic generaSphaeroplea andAtractomorpha as well. It is also suggested that the genusParietochloris gen. nov. be erected in thePleurastrophyceae for the species of Group III.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 246 (1989), S. 56-60 
    ISSN: 1434-4726
    Schlagwort(e): Carbonic anhydrase ; Vestibular organ ; Guinea pig ; Histochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Carbonic anhydrase activity was demonstrated cytochemically on an ultrastructural level in the vestibular end organs of the guinea pig. Reaction product was found in the dark cells, transitional cells, cells of the planum semilunatum and supporting cells. In the dark cells, reaction product was observed in the cytoplasm as well as in the basal infoldings. Reaction product was also observed in the basal infoldings of the transitional cells and the cells of the planum semilunatum. The globular structures inside the supporting cells, transitional cells and the cells of the planum semilunatum were also surrounded by the reaction product. These findings suggest that carbonic anhydrase may have different functions, such as water and ion transport, respiration, nutrition and calcium carbonate deposition in the vestibular end organs.
    Materialart: Digitale Medien
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 246 (1989), S. 169-172 
    ISSN: 1434-4726
    Schlagwort(e): Tympanic membrane ; Ultrastructure ; Sensory receptors ; Nerve endings
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Encapsulated nerve endings were found in both the subepidermal connective tissue and the lamina propria of a human tympanic membrane. The structure of the corpuscles was round or oval and contained a number of axon terminals with mitochondria and Schwann cell processes. Amorphous materials were present in the intercellular space. These features appear to be advantageous in transmitting mechanical forces on the capsule to the axon terminals and are comparable to the function of a mechanoreceptor. Resultant changes in the shape and stiffness of the tympanic membrane as the result of its dislocation indicate similar changes in the pressure on the corpuscle. The arrangement of the sensory corpuscles suggests that they may play a role in detecting pressure changes in the middle ear cavity.
    Materialart: Digitale Medien
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  • 62
    ISSN: 1435-5604
    Schlagwort(e): Intercellular communication ; Gap junction ; Calcification ; Collagen gel ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary To analyze the mechanism of initiation of cell-mediated calcification in hard tussue and its relationship to the frequency of gap junctions, enzymatically isolated cells from fetal rat calvaria cultured in collagen gels were observed ultrastructurally over a time course. Calcification was observed at 2–3 weeks after the initiation of culture when the seeding cellularity and the concentration of β-glycerophosphate were sufficiently high. In the collagen gels, round cells (R), spindle or stellate cells (S), and fat cells (F) were characterised morphologically. The ultrastructural features of initial calcification could be classified into 4 subtypes: 1) a large mass greater than 10 µm in diameter (Type I), 2) deposition associated with dead R cells or matrix vesicles (Type II), 3) intracellular deposition (Type III), and 4) other than Types I–III (Type IV). Type II was the most frequent (44.5%) and Type III was the least (6.8%). Gap junction was observed frequently between 1) R cells, 2) S cells, 3) between R cells and S cells. The frequency of gap junctions in collagen gels decreased statistically (X2-test; p〈0.001), when calcification was initiated. This cell culture system can be regarded as a useful model to analyze the initiation of cell mediated calcification in hard tissue. Gap junctions might function in cell communication and a decrease in their numbers could lead to cell death and, subsequently to calcification.
    Materialart: Digitale Medien
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  • 63
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 12 (1989), S. 24-28 
    ISSN: 0741-0581
    Schlagwort(e): Tissue culture ; Heart muscle cells ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: A technique for performing light, scanning, and transverse transmission electron microscopy on cultured cells grown within a single tissue culture flask is described. Permanent light microscopy slides are obtained by removing selected portions of the plastic tissue culture vessel and mounting them on glass slides with an aqueous mounting solution. The images obtained from these slides are superior to viewing through the bottom of the flask with an inverted stage microscope. For scanning electron microscopy, selected areas are also cut from the remainder of the vessel and prepared for viewing. The final portion of the culture container is transferred and attached to a new tissue culture vessel and prepared for transmission electron microscopy using alcohol instead of acetone and propylene oxide during dehydration, infiltration, and embedding.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 64
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 12 (1989), S. 323-330 
    ISSN: 0741-0581
    Schlagwort(e): Chromaffin cells ; Paraganglia ; Paraaortic organs ; Mitosis ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Mitotic activity often has been reported in embryonic and fetal sympathetic neuroblasts, principal sympathoblasts, and primitive sympathetic cells in various species at different stages of development. Postnatal adrenal medullary cells also are known to undergo mitosis, but such dividing capabilities rarely have been observed in the true postnatal extraadrenal chromaffin system. Although few in number, this work nevertheless has clearly identified such cells in varying stages of the mitotic cycle in the young dog, Syrian hamster, mouse, rabbit, and rat. The dividing cells were noted in paraaortic chromaffin organs, paraganglia, and within the inferior mesenteric ganglion as well. They displayed the morphological character usually associated with their adrenal medullary catecholaminergic counterparts, including numerous dense-cored vesicles known to be the harbingers of catecholamines and various peptides. Nerve endings were not noticed upon the mitotic cells. The phenomenon of dividing extraadrenal chromaffin cells augments existing data and perhaps suggests that these cells are more endocrine than neural in type and subservient to the adrenal medulla in its classic endocrine function.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Archives of gynecology and obstetrics 240 (1987), S. 33-43 
    ISSN: 1432-0711
    Schlagwort(e): Ovary ; Surface epithelium ; Perfusion ; Rabbit ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Using transmission electron microscopy we examined the morphology of the surface epithelium of the isolated and perfused rabbit ovary after an ovulatory dose of HCG. Rupture of follicles occurred in vitro approximately 13 h after HCG-injection and 6 h after the start of perfusion. The ultrastructural changes during the perfusion were similar to those occurring in vivo. The perfused ovarian epithelium had villous processes of varied architectural complexity with squamoid and cuboid epithelial cells. The superficial cells contained pinocytotic vesicles, coated and noncoated endocytotic caveolae, and occasional vacuoles. Dense bodies were more commonly found in vitro than in vivo. Occasionally structures similar to “Call-Exner-bodies” were found on the surface epithelium near to preovulatory follicles. Intercellular spaces of various sizes were also numerous. Disappearance of surface epithelium in the apex of follicles was often observed and the matrix of the tunica albuginea consisted of dissociated fibers and degenerating cells. This study showed that the isolated perfused rabbit ovary can serve as a model for studying the biology and pathology of ovarian surface epithelium.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Archives of gynecology and obstetrics 240 (1987), S. 137-146 
    ISSN: 1432-0711
    Schlagwort(e): Preovulatory granulosa cells ; Call-Exner body ; Fibrin ; Human ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of preovulatory granulosa cells may be distinct in follicles containing competent as opposed to non-competent oocytes. To test this assumption, granulosa cells were looked for in 36 follicular fluid aspirates from 8 patients taking part in an in vitro fertilization and embryo transfer program. Granulosa cells were absent from 16 aspirates and present in 20. Both aspirate types contained oocytes able to develop in culture. Granulosa cells were subdivided into three developmental stages. Stage 1 (5% of aspirates) showed proliferating cells, while stage 2 (60% of aspirates) and 3 (35% of aspirates) cells were in the preluteinization stage. These cells were recognizable by their number of lipid droplets and differentiated according to possession of a rough (stage 2) or smooth (stage 3) endoplasmic reticulum. Luteinization did not occur in these cells. All stages displayed desmosomes, gap junctions, and annular junctions. The structure of Call-Exner bodies and of fibrin deposits were unexpected findings. Our study indicates that there is no correlation between the previously used morphological parameters of granulosa cells and oocyte maturity.
    Materialart: Digitale Medien
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  • 67
    ISSN: 1432-2285
    Schlagwort(e): Cambial activity ; Frost hardiness ; Phenology ; Salix ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The ultrastructure of cells in the cambial region of Salix dasyclados Wim. (clone 78056) was studied during the development of winter hardiness and the onset of cambial activity in spring. Plants were grown at relative growth rates (RG) of 8% and 12% respectively, resulting in different nitrogen content in the stems. Frost hardiness of the plants was estimated by standardized freezing tests. Plants with a higher nitrogen status ceased growth later and started re-growth earlier in spring than plants with lower nitrogen content. Differences in ability to withstand low temperatures during autumn and spring were found between plants grown in the two nutrient treatments. During the development of frost hardiness in the autumn, the number of meristematic cells in the cambial region decreased. The cessation of meristematic activity was accompanied by cell wall thickening and ultrastructural changes in the cells. Frost hardiness increased from the ability to survive -6° C in October to survival of -80° C at the beginning of December. From November to February the cambial region comprised a layer of 2–3 thick-walled cells with conspicuous ultrastructural features. Starch accumulated in plastids in September, decreased during November to March and then increased again in accordance with changes of frost hardiness. Onset of cambial activity began between the end of March and the beginning of April, as shown by increased vacuolization of meristematic cells and mitotic activity. By April, the starch content had increased and lipolysis was observed. Frost hardiness had decreased, and plants with low and high nitrogen content were able to survive -15° C and -10° C, respectively. After budburst, all axillary shoot parts were damaged at temperatures below-3° C.
    Materialart: Digitale Medien
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 411 (1987), S. 509-514 
    ISSN: 1432-2307
    Schlagwort(e): Soft tissue neoplasm ; Sarcoma ; Rhabdoid cell ; Rhabdoid tumor ; Ultrastructure ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We report the occurrence of rhabdoid cells in several specified soft tissue sarcomas of round cell variety. The rhabdoid cells had an acidophilic cytoplasm containing a globular perinuclear inclusion and were characterised ultrastructurally by the presence of aggregates of 10 nm intermediate filaments. These filaments contained both cytokeratin and vimentin, as demonstrated immunohistochemically. Extensive sampling of soft tissue sarcomas revealed the presence of such cells in different types of soft tissue round cell sarcomas as follows: 12 of 13 cases of epithelioid sarcomas, 8 of 13 synovial sarcomas (composed predominantly of round cells), 6 of 20 extraskeletal myxoid chondrosarcomas and 4 of 4 round celled malignant mesotheliomas. We wish to stress that the appearance of rhabdoid cells is not a monopoly of one particular type of tumour.
    Materialart: Digitale Medien
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 412 (1987), S. 175-182 
    ISSN: 1432-2307
    Schlagwort(e): Appendix ; Colorectal neoplasm ; Carcinoid ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The clinicopathological features of six appendix and five bowel tumours with features of the so-called ‘goblet cell carcinoid’ are described. By light microscopy, these tumours were composed predominantly of mucous cells, together with variable proportions of endocrine and Paneth cells. Immunohistochemical and ultrastructural study confirmed this impression and no amphicrine cells were seen. The clinical course of all cases arising in the bowel, and three out of six appendix tumours was characterised by an aggressive behaviour with the development of widespread lymphatic and often intraperitoneal metastasis, but liver metastasis occurred in only one instance. We conclude, both from this study and from a review of the literature, that the ‘mixed crypt cell carcinoma’ forms a distinct clinicopathological entity justifying separate classification from adenocarcinoma and carcinoid tumour.
    Materialart: Digitale Medien
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 411 (1987), S. 93-98 
    ISSN: 1432-2307
    Schlagwort(e): Gliomatosis cerebri ; Brain tumour ; Ultrastructure ; Glial cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructural features of five biopsies of gliomatosis cerebri (GC) are described. Four main types of tumour cells are seen: anaplastic astrocytes poor in organelles with a variable amount of glial microfilaments; atypical oligodendrocytes with scanty cytoplasm in which microtubules are present; intermediate forms with aboundant cytoplasm rich in organelles, with microtubules and microfilaments; and small cells with round nuclei and a very scanty rim of cytoplasm. In two cases several concentrically folded cytoplasmic lamellae of glial processes were arranged either around themselves or around the perikaryon of other cells. This ultrasructural study indicates that GC is a neoplastic process of small undifferentiated elements, transitional forms of astroglia (to oligodendroglia) and anaplastic cells of astrocytic origin in all stages of development.
    Materialart: Digitale Medien
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 411 (1987), S. 293-298 
    ISSN: 1432-2307
    Schlagwort(e): Ectocervix ; Serotonin cells ; Calcitonin cells ; Ultrastructure ; Transitional epithelium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A systematic study of endocrine cells in the ectocervix was carried out using histochemical, immunohistochemical and ultrastructural techniques. Serotonin and calcitonin immunoreactive cells were demonstrated in this site. Serotonin and calcitonin immunoreactivities were coexpressed in the same endocrine cell. These distinctive cells were encountered in two main morphological varieties of ectocervical epithelium. Normal-appearing stratified squamous epithelium contained only very rare serotonin and calcitonin cells. In contrast, endocrine cells were fairly abundant in a specific epithelium termed “transitional-like”. This type of epithelium was not only confined to the transformation zone but could also extend onto the portio as far as the vaginal cut margin. In some cases, transitional-like epithelium bore morphological resemblance to urothelium. In other cases, it could be regarded as basal cell hyperplasia or immature squamous metaplasia. Of interest, serotonin and calcitonin cells have been well-documented as normal inhabitants of some other non-squamous epithelia, such as urothelium or pseudostratified columnar epithelium. Therefore, it is suggested that certain ectocervical epithelia show some similarities to urothelium, in respect of their morphological appearance and endocrine profile. Further investigations using more objective and specific markers of urothelial cells are needed to assess the exact degree of homology connecting all these types of epithelium.
    Materialart: Digitale Medien
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 412 (1987), S. 119-125 
    ISSN: 1432-2307
    Schlagwort(e): 16,16-dimethyl prostaglandin E2 ; Aspirin ; Tight junctions ; Stomach ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The canine gastric epithelium was exposed to solutions containing 20 mM aspirin and 20 mM aspirin + 30 µg/kg 16,16-dimethyl prostaglandin E2 (dmPGE2) for periods of three and forty minutes. No macroscopic hemorrhagic lesions were seen. Light microscopically, surface lesions were reduced from 10 percent (aspirin alone) to 2.5% (aspirin+dmPGE2). However, dmPGE2 does not appear to attenuate aspirin induced tight junction alterations. Discontinuities in the apical occluding complexes, hyperplastic tight junctions and stand number variability were documented in freeze frature replicas of aspirin as well as aspirin+ dmPGE2 treated dog stomachs. The results of these experiments would seem to suggest that 30 µg/kg dmPGE2 does not prevent aspirin induced damage to the tight junctions of the canine gastric epithelium or enhance their repair.
    Materialart: Digitale Medien
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 411 (1987), S. 561-568 
    ISSN: 1432-2307
    Schlagwort(e): Psammous desmo-osteoblastoma ; Ultrastructure ; Osteonectin ; Bone tumours ; Fibro-osseous lesion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Fibro-osteo-cemental lesions of the jaw bones are a heterogeneous group of diseases which present problems in classification. Psammous desmo-osteoblastoma is one of four newly proposed entities (Makek 1983) and has until now been characterized by its light microscopic, clinical and radiological features. On electron microscopy this tumour exhibits fibroblastic (preosteoblastic), osteoblastic and osteocytic cells and a globular mineralization unlike the mineralization of the psammoma bodies. Immunohistological investigations with anti-osteonectin, a bone specific protein linking mineral to collagen, showed positive intracellular staining in all tumour cells and extracellular staining in the osteoid. The psammoma bodies were, however, not stained. These results confirm the view of the osteogenic histogenesis of psammous desmo-osteoblastoma, with an osteogenic differentiation of the tumour cells, bone formation and association of psammoma bodies which are not of bone origin. This combination of findings supports the view that psammous desmo-osteoblastoma represents a new and distinct entity occuring in desmal preformed cranio-facial bones which should be incorporated in a revised WHO-classification.
    Materialart: Digitale Medien
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 410 (1987), S. 93-96 
    ISSN: 1432-2307
    Schlagwort(e): Heterogeneity ; Ultrastructure ; Colonic carcinoid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This report describes a colonic carcinoid tumor in which three, and possibly four, distinct cell types are distinguishable on the basis of their ultrastructure and granule morphology. These cell types closely resemble the normal endocrine cells of the large bowel, both in appearances and in relative frequency. The mixed composition of this tumor may have arisen either by parallel differentiation of distinct cell types, or by sequential maturation of one cell type.
    Materialart: Digitale Medien
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 410 (1987), S. 317-326 
    ISSN: 1432-2307
    Schlagwort(e): “Primary” endothelial cilia ; Endothelial centrioles ; Human atherosclerosis ; Ciliary transitional fibers ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary “Primary” cilia were present in the endothelial cells of human aortic fatty dots and streaks but not in those of normal intima. They had the features of cilia of the “9+0” axonemal configuration observed in many other cells. A lateral foot process and transitional fibers “anchored” the ciliary basal body in the cytoplasm, but rootlets were not identified in material examined. Ladder-like configurations interconnected the two centrioles (=diplosome) of control endothelium. The “primary” cilia of endothelium differed from those of the rudimentary type observed in smooth muscle cells in similar lesions of man, but shared many features with cilia of those present in experimental atherosclerosis in rabbit. Cilia were rarely described in vascular endothelium. It is believed that, to date, they were not reported to occur in normal or pathological arteries in man. It is being stressed that whereas the significance of these unusual organelles remains uncertain, their widespread occurrence may indicate that their role is more important than was believed previously, and they should cease being a curiosity only.
    Materialart: Digitale Medien
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 176 (1987), S. 281-294 
    ISSN: 1432-0568
    Schlagwort(e): Myotendinous junction ; Human growth ; Skeletal muscle ; Tendon ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The myotendon junction of human paravertebral skeletal muscle was studied by light and electron microscopy. Transverse and longitudinal sections of myotendinous regions of normal multifidus muscles were examined at three chronological stages from birth to maturity. Variations in the appearance of surface extensions at the terminal ends of muscle fibers consisted of brush-like evaginations at birth and villous-like projections in the adult. Regardless of age, they were invariably covered by a prominent external lamina, and mutually interdigitated with connectivetissue elements in the adjacent tendon. Various stages of myofibrillar assembly and sarcomere alignment were evident in the muscle fiber terminus at birth. With advancing age, splitting of terminal sarcomeres at Z bands commonly gave rise to diverging myofilament bundles that attached to electron-dense patches under the sarcolemma. In these regions, leptomeric organelles were also encountered in neonatal and adolescent myotendons. At all stages, the ends of muscle fibers possessed cytological features consistent with active synthesis and secretion. Densely-packed sarcoplasmic organelles including multiple Golgi complexes, clusters of ribosomes, mitochondria, cytoplasmic vesicles, and elements of rough- and smooth-surfaced endoplasmic reticulum were prevalent. Peripheral and centrally-placed heterochromatic nuclei with prominent nucleoli were arranged singly or in groups at the ends of muscle fibers. Satellite cell profiles and unmyelinated axons in the subjacent tendon were also identified at these sites in the adult. Fibroblasts in growing tendon were plentiful, and at all stages, possessed morphological features indicative of high metabolic and secretory activities.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 177 (1987), S. 131-138 
    ISSN: 1432-0568
    Schlagwort(e): Capillaries ; Tooth pulp ; Tight junctions ; Odontoblasts ; Ultrastructure ; Mineralisation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The relative roles of capillaries and odontoblasts in the process of dentinogenesis and in pulp reactions to trauma and pathology are not clear. Contributing to the problem is the paucity of information on odontoblast —capillary relationships and tight junctions between odontoblasts. Using light microscopy the capillaries have now been examined in semithin transverse sections of perfusion fixed teeth at different positions in the long axis from the apical foramina to the pulp horns. Odontoblastic capillaries were prominent in the coronal and middle regions of canines and present at the same levels of incisors. In the pulp horns and just coronal to the pulp horns capillaries were all subodontoblastic but near the apex there were also a few odontoblastic capillary profiles. Transmission electron microscopy on ultrathin sections revealed that a high proportion of middle and coronal odontoblastic capillary profiles were fenestrated but subodontoblastic profiles coronal to the pulp horns were the most fenestrated. In a search for tight junctions in ultrathin sections some typical strands were observed between odontoblasts. The difficult of obtaining the latter evidence was explained by the cellular arrangement of the odontoblasts which differed markedly from an ideal parallel, apically coplanar arrangement. The results question the possibility that there is a direct exchange of materials between pulp capillaries and dentine in teeth of limited growth and provide a baseline for future experiments to test the permeability of the odontoblast layer.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 73 (1987), S. 281-286 
    ISSN: 1432-0533
    Schlagwort(e): Teratoma ; Nervous tissue ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of the nervous tissue in a benign ovarian teratoma is described. This tissue was organized into areas having both “meningel” and “ependymal” surfaces, between which were found astrocytes, ependymal cells, neurones with synapses and microglia. These cells all had ultrastructural similarities to their normal counterparts in the nervous system. In addition, some signs of degenerative change — due possibly to the abnormal location of the nervous tissue — were observed. Oligodendrocytes and myelin were absent, possibly because of vascular insufficiency.
    Materialart: Digitale Medien
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  • 79
    ISSN: 1432-0533
    Schlagwort(e): Cerebellum ; Histogenesis ; Cisdichlorodiammineplatinum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The aim of this electron microscopy study was to further investigate the effects of cis-dichlorodiammineplatinum (cis-DDP) on the cerebellum of the immature rat. Ten-day-old animals were treated with cis-DDP subcutaneously and killed after 1, 7, 15 or 21 days. On postinjection day 1, cis-DDP effects were evident mainly in the external granular layer, with nuclear damage in many dividing cells, while their cytoplasm appeared to be less affected. Some binucleate cells were also present. On the contrary, in postmitotic or more differentiated cells, only cytoplasmic alterations were found. At later stages (postinjection day 7), the frequency of damaged cells in the external granular layer decreased, but there was a cellular deficit in the internal granular layer. Many postmitotic neurons underwent coagulative necrosis. Finally (postinjection days 15 and 21), the cellular deficit was partly compensated for by “reactive” structures, e.g., glial cell fibers, which underwent hypertrophy after initial edema. Moreover, packing densities of Bergmann astrocytes and oligodendrocytes were higher.
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 73 (1987), S. 92-98 
    ISSN: 1432-0533
    Schlagwort(e): Spinal gliomas ; Vascular proliferation ; Ethylnitrosourea ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The histology and ultrastructure of ten spinal cord gliomas, mainly oligodendrogliomas, induced transplacentally in rat with ethylnitrosourea were studied. The characteristic feature of seven spinal tumours was distinct delineation of neoplastic tissue from the edematous surrounding zone by a ring of irregular, proliferating capillaries, among which immature capillary buds prevailed. The alterations were proliferation of endothelium with endothelial overlapping, elongation of interendothelial junctions and enhancement of pinocytotic vesicles on luminal and abluminal surfaces. The basal membranes, besides other changes, were often replaced by some floccular condensations. In the edematous zone the capillary walls were deprived of contact with glial processes. The lack of contact between astrocytic processes and vascular wall may contribute to the persistent immature state of peripheral capillaries.
    Materialart: Digitale Medien
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  • 81
    ISSN: 1432-0568
    Schlagwort(e): Serotonin ; Substantia nigra ; Mammals (rat, cat, Macaca fuscata) ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The distribution of serotonin-containing nerve fibers in the substantia nigra of the rat, cat and monkey was studied with a highly sensitive peroxidase-antiperoxidase immunohistochemical method. Serotonin fibers in the substantia nigra of all species consisted of fine varicose fibers and formed a fine network. In the zona compacta of all species, serotonin fibers were sparsely distributed. In the zone reticularis of the rat and cat, these fibers were densely distributed and their distributional pattern was almost uniform, while in the monkey such fibers were unevenly distributed and high and low dense areas were intermingled. In the pars lateralis of all species, serotonin fibers were diffusely distributed, and the distributional density was much higher in the cat and monkey than in the rat. Immunoelectron-microscopic studies further revealed that a majority of the labeled varicosities in the rat substantia nigra were in close apposition to peridendritic axon terminals and were also free in the neuropil; occasionally they exhibited symmetrical synapses of “en passant” type with non-immunoreactive dendrites or somata. Our results support a functional significance of serotonergic regulation of the substantia nigra in mammals.
    Materialart: Digitale Medien
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 175 (1987), S. 467-475 
    ISSN: 1432-0568
    Schlagwort(e): Mouse spermiogenesis ; Constitutive heterochromatin ; Nucleolus organizing regions ; Fluorochrome ; Staining ; EM silver staining ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In this study, the selective fluorochrome staining of constitutive heterochromatin and a specific ultrastructural silver-staining of nucleolar material (i.e., the nucleolus organizing regions) were undertaken to be used as indicators for the chromosomal arrangement during mouse spermiogenesis. Since in mice all somatic chromosomes are telocentric and the constitutive heterochromatin and nucleolar organizing regions are closely associated to the centromeres, this combination of techniques provided for the first time ultrastructural evidence 1) for the dispersion of the constitutive heterochromatic chromocentre and a centrifugal migration to the postacrosomal portion of the nuclear envelope where constitutive heterochromatin seems to mediate the assembling of microtubules in the so-called manchette. As elongation continues, the constitutive heterochromatin migrates back into central position and forms the “focous of earlier condensing chromatin”, which initiates further chromatin condensation. 2) The fate of the nucleolus during spermiogenesis could also be further clarified: The nucleolus is first associated with the chromocentre, but starts to disintegrate during elongation phase. However, argyrophilic remnants are still visible in the centre of the nucleus, pointing to an ongoing transcriptional activity. When they final disappear, they leave behind “nuclear vacuoles” in the dense chromatin mass of the mature sperm nucleus.
    Materialart: Digitale Medien
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 176 (1987), S. 35-40 
    ISSN: 1432-0568
    Schlagwort(e): Bovine ; Oocyte maturation ; Meiosis ; Nucleus ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cumulus-oocyte complexes were obtained from cow ovaries by aspiration from small (1–6 mm in diameter) antral follicles after slaughter. Complexes with a compact multilayered cumulus investment were cultured and subsequently processed for electron microscopy after various periods of culture. By morphological criteria the oocytes could be divided into the following sequence of meiotic stages. The oocyte nucleus I stage was characterized by a spherical nucleus located peripherally in the ooplasm while undulation of the nuclear envelope and initial chromatin condensation was seen at the oocyte nucleus II stage. The oocyte nucleus breakdown stage was characterized by formation of long slender projections from the nuclear envelope in which the envelope doubled back on itself, appearance of dense areas and haphazardly oriented microtubules in the nucleus, marked condensation of the chromatin, and dissolution of the nuclear envelope into irregular vesicles and tubules. The condensed chromatin I stage was characterized by the location of condensed chromatin configuration and uniformly oriented microtubules in a dense area peripherally in the ooplasm while the final condensed chromatin II stage was characterized by a gradual invasion of condensed chromatin configurations into a dense area combined with the presence of the first polar body in the perivitelline space.
    Materialart: Digitale Medien
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 177 (1987), S. 91-96 
    ISSN: 1432-0568
    Schlagwort(e): Ultrastructure ; Human egg ; Human embryo ; Cleavage embryo
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A two-cell human embryo recovered from the Fallopian tube 82 h following the LH peak in plasma and 37 h after a single episode of intercourse was examined by transmission electron microscopy. At the time of recovery the embryo was denuded of cumulus cells, and both the zona pellucida and the two adjoining blastomeres were intact. The finding of two polar bodies in the perivitelline space, two nucleated blastomeres and remnants of the fertilizing sperm tail within the cytoplasm of one of them, were considered as evidences that the embryo was normally fertilized. Among the most compicuous features found were the presence of very distinct desmosome-like structure between blastomeres, and the cytoplasmic cell organelles distribution in three areas referred as: a sub-cortical, a middle and a perinuclear bands. An outstanding feature was the extensive blebbing of the nuclear envelope. In general, the features seem to correspond to a normally developing two-cell embryo undergoing cleavage at a normal rate.
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 177 (1987), S. 147-152 
    ISSN: 1432-0568
    Schlagwort(e): Atrial myocardium ; Vagotomy ; Monkey ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of the atrial myocardium in the monkey (Macaca fascicularis) was studied after bilateral cervical vagotomy and survival times of 1, 3, 5, 7, 10, 21 and 28 days. During the first week after vagotomy, a few atrial cells showed a reduction in the sarcoplasm, crowding of the myofibrils, peripheral dispersion and reduced intercristal density of the mitochondria and increased sarcoplasmic reticulum and glycogen particles. In some profiles, there was increased electron density and granularity at the I bands and the intercalated discs. The number of such affected cells increased in the subsequent days such that by 21 to 28 days about 50% of the cells were estimated to be affected. During the latter stages further changes included, the degradation of the myofilaments and increased electron density, disorganisation and disintegration of the digital extensions at the intercalated discs. Throughout the experiments there was a leucocytic infiltration, more evident in the longer survival times.
    Materialart: Digitale Medien
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 175 (1987), S. 399-410 
    ISSN: 1432-0568
    Schlagwort(e): Implantation ; Marmoset ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructural morphology of the initial stages of implantation in the marmoset monkey (Callithrix jacchus) was studied in pregnant monkeys at known time intervals after ovulation. The earliest samples, obtained 13 days after ovulation, displayed both cytotrophoblast and syncytiotrophoblast. The cytotrophoblast was restricted to the blastocoel, whilst syncytiotrophoblast intruded to the endometrial basal lamina. At later stages, days 16 and 19 after ovulation, both cytotrophoblast and syncytiotrophoblast had extended laterally around the uterus, and the syncytiotrophoblast also extended deeper into the maternal tissnes. The mesoderm layer was first discernible at 19 days after ovulation. At 23 days after ovulation the syncytiotrophoblast surrounded the maternal blood vessels entirely. In this study syncytiotrophoblast was not observed to breach the maternal blood vessels, even at 31 days after ovulation. Early cytotrophoblast columns could be seen at 31 days after ovulation. The endothelial cells lining the maternal blood vessels displayed hypertrophy from the earliest stages (day 13) onwards, although a true decidual response was only observed in samples of 23 and 31 days after ovulation.
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 176 (1987), S. 41-44 
    ISSN: 1432-0568
    Schlagwort(e): Bovine ; Oocyte maturation ; Meiosis ; Gap junction ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cumulus-oocyte complexes were obtained from cows by aspiration of small (1–6 mm in diameter) antral follicles after slaughter. Complexes with a compact multilayered cumulus investment were cultured and processed for transmission electron microscopy after different periods of culture including a 0 h control group. In 0 h control oocytes the cumulus cells had numerous projections which penetrated the zona pellucida and established gap junctions with the oolemma. A partial loss of these junctions was noticed as an early event of oocyte maturation occurring within the first 3 h of culture. A low frequency of gap junctions was maintained until 12–18 h of culture where the junctional contact was completely disrupted. This decrease in intercellular communication was parallelled by resumption of oocyte meiosis.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 176 (1987), S. 231-237 
    ISSN: 1432-0568
    Schlagwort(e): Embryonic chick heart ; Interventricular septum ; Mesenchymal tissue ; Endocardial activation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Light and electron microscopic studies of frontal and sagittal sections of embryonic chick hearts (Stages 25, 28–29), reveal mesenchymal tissue in the cephalic portion of the interventricular septum. The endocardium of this cephalic portion contains reoriented and invaginated cells with pseudopodia; in addition there are cells immediately subjacent to the endocardium. Similar cellular events take place during the formation of mesenchymal tissue in the atrioventricular and conotruncal regions. In these regions the mesenchymal tissue originates by means of an endocardial activation process. The structural characteristics of the formation of the cephalic portion of the interventricular septum suggest that local mesenchymal tissue is contributed by the endocardium. However, based upon the close anatomic relationship observed by us between the mesenchymal tissues of the atrioventricular canal, conotruncal region and the cephalic portion of the interventricular septum; we do not discard a contribution by migration of cells from atrioventricular and conotruncal regions to the interventricular septum.
    Materialart: Digitale Medien
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 279 (1987), S. 459-464 
    ISSN: 1432-069X
    Schlagwort(e): All-trans retinoic acid ; Epidermal cells ; Ultrastructure ; Differentiation ; Stratification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of all-trans retinoic acid on human epidermal cell cultures were studied using ultrastructural techniques. Differentiation and stratification were reduced in retinoic acid treated epidermal cells. Treated cells developed a rounded appearance and seemed to contain more granules and vacuoles than usual. Desmosomes were not found in treated cells.
    Materialart: Digitale Medien
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 75 (1987), S. 147-155 
    ISSN: 1432-0533
    Schlagwort(e): Esthesioneuroepithelioma ; Ultrastructure ; Immunohistochemistry ; Neurofilament protein (NFP) ; Keratin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of esthesioneuroepithelioma was investigated ultrastructurally and immunohistochemically, using antibodies against neurofilament protein (NFP), glial fibrillary acidic protein (GFAP), keratin, neuron-specific enolase (NSE), S-100 protein (S-100), and tyrosine hydroxylase (TH). The tumor initially manifested as an epidural mass in the anterior cranial fossa in a 64-year-old man, and about 31/2 years later, autopsy further revealed extensive metastases to the lymph nodes of the neck and thoracic cavity. In the cranial and nasal cavities, the tumor was composed of fairly uniform, ill-defined cells arranged in nests which were surrounded by a fibrovascular stroma. These histological features were reproduced in the metastatic tumor nodules with frequent occurrence of tubular arrangements of the tumor cells. Ultrastructurally, two different cell types were well recognized by their characteristic morphological features, which were reminiscent of sensory neurons and sustentacular cells of the olfactory epithelium. No dense-cored secretory granules were observed in the tumor cells. Immunohistochemically, the tumor showed a variable number of cells positive for NFP, keratin, NSE and S-100. NFP was present in a relatively small number of cells, which were found diffusely in the nests. Keratin was observed in the cells mainly located at the periphery. NSE-positive cells tended to form irregular clusters in the center. A few S-100-positive cells were found, without any particular arrangement. These findings indicated that the present tumor, which actually arose in the superior nasal cavity, consisted of cells differentiating in at least two distinct directions, neuronal and epithelial, and strongly suggested that the tumor was of true olfactory epithelium origin, or more precisely, derived from the bipotential, undifferentiated basal cells of this epithelium.
    Materialart: Digitale Medien
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 74 (1987), S. 307-312 
    ISSN: 1432-0533
    Schlagwort(e): Ganglioglioma ; Neuronal degeneration ; Ultrastructure ; Brain stem ; Brain tumor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A brain stem ganglioglioma in a 9-year-old female was examined ultrastructurally. The constituent neuronal (ganglion) cells displayed various ultrastructural features of neuronal degeneration including Hirano, Lafora and zebra bodies, inclusion-like aggregates of neurofilaments and large dilatations of rough endoplasmic reticulum. Although similar observations have been reported in peripheral neuronal tumors, this is the first reported occurrence in ganglioglioma, an uncommon tumor in the central nervous system. The coincidence of these alterations in the present tumor appeared to be of great interest, however, their exact etiology remained uncertain.
    Materialart: Digitale Medien
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 73 (1987), S. 400-402 
    ISSN: 1432-0533
    Schlagwort(e): Ultrastructure ; Ependyma ; Experimental hydrocephalus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary New ultrastructural alterations of the ependymal cells in the altered container model of experimental feline hydrocephalus are described. These include half desmosomes and a basal lamina on the apical surface of the ependymal cells, punctate adhesion-like structures between intraventricular mononuclear cell and the apical surface of the ependymal cells and unusual distortion of the ependymal cells. The significance of these previously unreported morphological alterations is unknown.
    Materialart: Digitale Medien
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  • 93
    ISSN: 1432-0533
    Schlagwort(e): Brain ; Global ischemia ; Ultrastructure ; Ionic changes ; Ca
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A time course of tissue ionic changes, and their relation to ultrastructural findings during reperfusion following a 15-min global ischemic brain insult was studied in a dog model. Parietal cortex was analyzed for Ca, Na, K, Mg and Fe in controls and after 10 min, 2, 4, and 8 h of reperfusion. After 8 h of reperfusion, the mean values (μmol/g tissue wet wt.) for Ca (control=1.43, 8 h=2.76) and Na (control 60.4, 8 h=107.4) doubled and K (control=90.4, 8 h=48.5) decreased to half that of the control. Ultrastructural studies and subcellular localization of calcium in parietal cortex of in situ-fixed brains after 8 h showed cortical neurons with clumping of nuclear chromatin, dilatation of endoplasmic reticulum and disruption of plasma membranes. Large amounts of electron-dense precipitates of calcium were present within dilated astrocytic processes, synaptic vesicles, cytoplasm of edematous dendrites and mitochondria. Cortical neurons from postischemic dogs without reperfusion showed only slight chromatin clumping and edema of astrocytic processes, but no calcium accumulation. The large ionic shifts noted between 4 and 8 h of reperfusion, indicate a progressive inability of the cells to maintain normal transmembrane gradients of these ions and may reflect a membrane destructive process, as demonstrated ultrastructurally at 8 h. Enhanced calcium entry into the neuron during reperfusion appears to be a part of the cytotoxic mechanism leading to neuronal necrosis.
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 74 (1987), S. 1-8 
    ISSN: 1432-0533
    Schlagwort(e): Intermediate filaments ; Glial fibrillary acidic protein (GFAP) ; Vimentin ; Ultrastructure ; Glioma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Glial filaments contain vimentin and glial fibrillary acidic protein (GFAP). The question of how glial filaments change morphologically according to the expression of vimentin and/or GFAP has remained unclear. In this study, immunohistochemical and ultrastructural examinations were performed on the subcutaneously transplanted tumors of two clones (F6B3 and G10A10) derived from a mouse glioma. F6B3 tumor expressed GFAP and vimentin in large quantities. G10A10 tumor expressed plenty of vimentin but only a little of GFAP. Ultrastructurally, F6B3 tumor contained abundant cytoprocesses in most of which numerous intermediate filaments (IFs) were arranged in a parallel array. On the other hand, only a small number of the processes were seen in G10A10 tumor, which showed a few IFs arranged either randomly or sparsely in the processes. Both tumors commonly had the IFs accompanied by visible sidearms, but there was a difference in that the smooth and firm IFs were confined to part of F6B3 tumor. Thus, the comparison made between the two models presented differences in the content, arrangement and morphology of IFs, as well as in the manner of GFAP expression, suggesting correlation between these differences.
    Materialart: Digitale Medien
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  • 95
    ISSN: 1432-0533
    Schlagwort(e): Neuronal ceroid-lipofuscinosis ; Membranous cytoplasmic body ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An autopsy case of adult neuronal ceroid-lipofuscinosis was examined. The clinical picture was charaterized by gait disturbance, bulbar palsy and dementia. Histopathologically, diffuse neuronal loss was found throughout the central nervous system. The remaining neurons, predominantly in the motor nuclei of the spinal cord and brain stem, were swollen with storage material. Observed under the electron microscope the storage material showed various ultrastructures, such as lipofuscin-like bodies, pleomorphic lipid bodies, curvilinear profiles and finger-print profiles, in different regions of the central nervous system. In the ballooned neurons of the spinal anterior horn, many membranous cytoplasmic bodies and curvilinear profiles were intermingled within the same cell and were continuous with each other. Biochemically,N-acetyl neuraminic acid content was significantly increased in the spinal anterior horn. These findings suggest the localized increase of ganglioside in that region.
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 279 (1987), S. 173-179 
    ISSN: 1432-069X
    Schlagwort(e): UV-A pigmentation ; Ultrastructure ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary UV-A-induced skin pigmentation was investigated morphologically in semithin and thin sections from 11 volunteers, using different irradiation modalities (single doses of 10,50 and 100 J/cm2). Visible skin pigmentation was observed in all but two probands, and erythema in two; pronounced pigmentation was present after repeated irradiation only. Contralateral non-irradiated, UV-B-irradiated and suntanned skin specimens were used as controls. There was an increase in the number of clear cells in the basal layer (x 1.6) and particularly of large clear cells (x 1.7) after repeated irradiation. Also, the number of melanosomes in melanocytic dendrites (x 2.8) increased after repeated irradiation. The number, size and shape of the melanosome complexes in both basal and suprabasal keratinocytes remained unchanged, even when a distinction was made between central and peripheral location. In contrast, suntanned skin showed an increase in melanosome complexes in basal (x 5.8) and suprabasal (x 3.7) keratinocytes. It is concluded that UV-A-induced skin pigmentation differs in some ways from UV-B or sun-induced melanogenesis, and that the clinical grade of tanning cannot accurately be determined by ultrastructural methods.
    Materialart: Digitale Medien
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 196 (1987), S. 367-371 
    ISSN: 1432-041X
    Schlagwort(e): Vitellogenesis ; Bufo marinus oocyte ; Yolk-platelet membrane ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Oocytes of the toad Bufo marinus have been studied by means of thin section and particularly freeze-fracture electron microscopy to characterize the cytoplasmic membranes around the yolk organelle, and the storage of yolk material in precursors and platelets. This appears to be a previously unknown type of yolk-platelet formation. During yolk-organelle development from the primordial precursor to the bi-partite fully grown yolk platelet, numerous lipoid droplets are attached to the periphery of the platelet, indicating an intense uptake of lipids. As is typical for amphibians, the fully grown yolk platelet has a crystalline internum covered by a dense osmiophilic externum, and the whole organelle is enveloped by a plasma membrane that shows no direct connection or fusion with endocytotic vesicles. The yolk membrane exhibits few intramembraneous particles (IMPs) at the core areas and some more where it borders fields of lipoid droplets. Here the IMPs show a net-like arrangement in the furrows between adjacent droplets.
    Materialart: Digitale Medien
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 67 (1987), S. 41-51 
    ISSN: 1432-1106
    Schlagwort(e): Trauma ; Neuron ; Culture ; Calcium ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cultured mouse spinal neurons were fixed at three different intervals after dendrite amputation: within the first 15 min, at 2 h and at 24 h. Dendrites were amputated at lesion distance of either 50 μm (31% probability of cell survival) or 100 μm (53% probability of cell survival) from the edge of their perikarya. When fixed within 15 min, operated neurons showed a two-phase gradient of ultrastructural damage which spread from the transection site towards the perikaryon. At 2 h after dendrite amputation all neurons operated close to their perikarya were categorized as either viable, moribund or dead, based on their appearance with phase contrast microscopy. These categories of response to physical trauma corresponded to distinctly different ultrastructural changes. Moribund neurons were filled with membrane-bound vesicles which were derived from swollen mitochondria and grossly dilated cisternae of the smooth endoplasmic reticulum. The cytoplasm of dead neurons contained large clear areas and many condensed, dark mitochondria. Both moribund and dead neurons lacked cytoskeletal elements. All of these ultrastructural changes are hypothesized to be the result of an increase in the intracellular concentrations of free calcium. Although evidence of residual mitochondrial swelling was present in some surviving neurons at 24 h, the ultrastructure of others was comparable to that of control cells. Some surviving neurons had terminal swellings at the ends of the severed neurites which were very similar to retraction balls of transected axons after CNS trauma.
    Materialart: Digitale Medien
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  • 99
    ISSN: 1432-0738
    Schlagwort(e): Silver toxicity ; Cultured macrophages ; Cell death ; Ultrastructure ; Lipid peroxidation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The effects of silver on cultured mouse peritoneal macrophages were examined by estimation of cell survival and by light and electron microscopy. Additon of silver lactate to the culture medium at final concentrations of 40 and 80 μM resulted in coagulation necrosis and rapid cell death. At lower concentrations cell structure appeared normal. However, the rate of cell death at 20 μM silver lactate was increased as compared to controls. Silver, visualized by physical development/autometallography, was invariably located in lysosomes. The production of malondialdehyde in mouse liver of silver-treated mice as compared to controls was also examined. This lipid peroxidation product had increased to the same amount in animals treated with silver for either 3 days or with only one silver injection 4 h before examination. This study has demonstrated that silver affects viability and structure of cultured macrophages, possibly due to induction of lipid peroxidation, as demonstrated to occur in the liver of silver-exposed mice.
    Materialart: Digitale Medien
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 148 (1987), S. 150-154 
    ISSN: 1432-072X
    Schlagwort(e): Bacteroides ; Vesicles ; Ultrastructure ; Cellulolytic bacteria ; Rumen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In 3-day-old cultures of Bacteroides succinogenes grown on filter paper, no cell division was observed. When grown on cellulosic substrate, bacteria exhibited vesicles clustered within cell wall pockets. In 2 day-old filter paper cultures, cells adhered tightly to the substrate. Twenty to 30% of them were dividing. There were cell wall pockets in about 25% of the bacteria, but no vesicles. Whether they adhered to the cellulosic substrate or not, and irrespective of the age of the bacteria, storage polysaccharides were found in the form of dense granules in the cytoplasm. It would appear that vesicles are not essential for cellulose degradation, but are rather a sign of ageing of the cells.
    Materialart: Digitale Medien
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