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  • 2000-2004  (52)
  • 1975-1979  (1.318)
  • 1955-1959  (11)
  • 1890-1899
  • 1880-1889
  • Atomic, Molecular and Optical Physics  (745)
  • Ultrastructure  (588)
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of comparative physiology 186 (2000), S. 347-357 
    ISSN: 1432-1351
    Schlagwort(e): Key words Crustacean ; Sensorimotor ; Ultrastructure ; Multilamellar sheath ; Myelinated axons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Speed of nerve impulse conduction is greatly increased by myelin, a multi-layered membranous sheath surrounding axons. Myelinated axons are ubiquitous among the vertebrates, but relatively rare among invertebrates. Electron microscopy of calanoid copepods using rapid cryofixation techniques revealed the widespread presence of myelinated axons. Myelin sheaths of up to 60 layers were found around both sensory and motor axons of the first antenna and interneurons of the ventral nerve cord. Except at nodes, individual lamellae appeared to be continuous and circular, without seams, as opposed to the spiral structure of vertebrate and annelid myelin. The highly organized myelin was characterized by the complete exclusion of cytoplasm from the intracellular spaces of the cell generating it. In regions of compaction, extracytoplasmic space was also eliminated. Focal or fenestration nodes, rather than circumferential ones, were locally common. Myelin lamellae terminated in stepwise fashion at these nodes, appearing to fuse with the axolemma or adjacent myelin lamellae. As with vertebrate myelin, copepod sheaths are designed to minimize both resistive and capacitive current flow through the internodal membrane, greatly speeding nerve impulse conduction. Copepod myelin differs from that of any other group described, while sharing features of every group.
    Materialart: Digitale Medien
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  • 2
    ISSN: 1437-773X
    Schlagwort(e): Key words Mitogen-activated protein kinase (MAPK) ; Ischemia reperfusion injury ; Heart ; Ultrastructure ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The mitogen-activated protein kinase (MAPK) family is considered to be activated by stress, but the role of the MAPK family is still unknown in cardiac pathology. In the present study, not only the localization of MAPKs such as the extracellular responsive kinase (ERK), c-jun N-terminal kinase (JNK), and p38 MAPK (p38), but also ultrastructural changes were investigated in the ischemia-reperfusion model of Wistar rats. At 5, 10, 30, 60, and 180 min reperfusion after 30 min ischemia by occluding the coronary artery, the expression of these MAPKs was increased in blood vessels and cardiomyocytes by Western blotting and immunohistochemical methods. In addition, after ischemia reperfusion, various ultrastructural changes such as decreased glycogen granules, mitochondrial swelling, and myolysis were observed in the blood vessels and cardiomyocytes. These results suggest that protein kinases may regulate numerous biological processes, including the regulation of contraction and ion transport.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1437-773X
    Schlagwort(e): Key words Gonadotroph adenoma ; FSH ; Childhood ; Ultrastructure ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Female gonadotroph adenomas with endocrinological symptoms are uncommon. Six cases of such adenomas have been reported in the literature: two were girls who presented with precocious puberty and four were premenopausal women with accompanying multiple ovarian cysts. We describe here a 10-year-old Japanese girl with a gonadotroph macroadenoma and present detailed morphological findings of the tumor. The patient's chief complaints were nausea, abdominal distention, and abdominal pain. Abdominopelvic ultrasonography and magnetic resonance imaging (MRI) revealed bilateral multiple ovarian cysts. Endocrinological assays showed elevated serum follicle-stimulating hormone (FSH) (33.7 mIU/ml) and estradiol (3840 pg/ml). MRI of the head showed a large pituitary tumor. Two transsphenoidal operations and subsequent radiation therapy were performed. Immunohistochemically, more than half the tumor cells were positive for anti-FSH-β monoclonal antibody. Ultrastructurally, the tumor cells exhibited a fairly uniform picture of rounded cells. Their nuclei were slightly irregular and contained heterochromatin, and their cytoplasm contained many round, dense core granules, measuring 140–260 nm in diameter, together with well-developed organelles. An in vitro study showed that the tumor cells in primary culture produced FSH (1089.0 mIU/ml). To our knowledge, this is the first immunohistochemical and ultrastructural study of an FSH-secreting gonadotroph adenoma occurring in childhood.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1437-773X
    Schlagwort(e): Key words Apoptosis ; Helicobacter pylori ; Fibroblasts ; Smooth muscle cells ; Ultrastructure ; Gastroduodenal ulcer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract It has been considered that Helicobacter pylori (H. pylori) infection is a major cause of human gastritis and gastroduodenal ulcers (G-DU). Many investigations of the relationship between H. pylori and apoptosis have been reported recently. However, these studies focused mostly on epithelium, using the TUNEL method. In the present study, we evaluated by electron microscopy the occurrence of apoptosis in the mesenchymal cells of lamina propria mucosae infected with H. pylori. Gastric biopsy specimens from 37 H. pylori-infected G-DU patients and 8 noninfected volunteers were examined with both light and electron microscopy and analyzed by the TUNEL method. The TUNEL method showed no significant difference between H. pylori-infected and noninfected cases. In contrast, electron microscopy revealed significant numbers of apototic fibroblasts and smooth muscle cells in H. pylori-infected lamina propria mucosae, with a diminished number of collagen fibers in surrounding areas. These areas showed edematous changes histopathologically. These results indicated that H. pylori infection induces apoptosis of fibroblasts and smooth muscle cells in lamina propria, with decrease in the numbers of collagen fibers, suggesting that these alterations may be affected by exaggerate acid secretion, decrease mucus protecting factors, and result in ulcer formation.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Medical electron microscopy 33 (2000), S. 109-114 
    ISSN: 1437-773X
    Schlagwort(e): Key words Ciliogenesis ; Ciliated cell ; Abnormal cilia ; Basal body ; Ultrastructure ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Cilia are motile processes extending from the basal bodies, playing important roles in the mucociliary clearance in the respiratory tract and the transport of the ovum from the ovary to the uterus in mammals. Ciliogenesis is divided into four stages: (1) duplication of centrioles; (2) migration of centrioles to the apical cell surface to become basal bodies; (3) elongation of cilia containing the axoneme; and (4) formation of accessory structures of basal bodies. The orderly course of ciliogenesis appears to be disturbed by various internal and external factors and, as a result, various unusual forms of the ciliary apparatus develop in the cell. Inhibition of basal body migration results in development of intracytoplasmic axonemes, cilia within periciliary sheaths, and intracellular ciliated cysts. Swollen cilia and the bulging type of compound cilia are formed during ciliary budding and elongation. This review also discusses the origin, composition, and function of the centriolar precursor structures.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Medical electron microscopy 33 (2000), S. 135-142 
    ISSN: 1437-773X
    Schlagwort(e): Key words Elastic system fiber ; Ultrastructure ; Fibrotic human liver ; Oxytalan fiber ; Elaunin fiber
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The network of elastic system fibers in human fibrotic liver was investigated by histological methods, immunohistochemical staining, and electron microscopy. Type III collagen was seen not only in regions of portal fibrosis but also in the sinusoidal wall. However, elastic system fibers were not found in the Disse space of the sinusoidal wall. Elastic system fibers including oxytalan, elaunin, and elastic fibers were found successively in the course of elastogenesis. A few normal oxytalan fibers and abnormal oxytalan fibers were observed in the periportal tracts. Few normal elaunin and abnormal elaunin fibers were observed in regions of portal fibrosis but not in the surrounding margin. Elastic fibers, only in scarce amounts, were observed around the portal veins in the case of chronic active hepatitis but not in acute hepatitis. Abnormal oxytalan fibers were seen as a bundle of wavelike microfibrils and had an irregular arrangement. Abnormal elaunin fibers were not associated with bundles of microfibrils. Abnormal elaunin fibers in large amounts were found interspersed with spiraled collagen, which most likely indicates that the oxytalan fibers degenerated in the course of elastogenesis. Thus, in a fibrotic liver it is possible that synthesis of normal elaunin and elastic fibers does not occur or that the quantity of such fibers synthesized may be small because of the effect of the degenerated oxytalan fibers. As a characteristic of liver fibrosis, the composition of abnormal elastic system fibers and spiraled collagen differs from that in other fibrotic organs.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1437-773X
    Schlagwort(e): Key words Adenoid basal carcinoma ; Uterine cervix ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Adenoid basal carcinoma of the uterine cervix is a rare tumor with a favorable prognosis. A case of adenoid basal carcinoma (ABC) of the uterine cervix was studied using light and electron microscopy. The patient was a 74-year-old Japanese woman who had undergone hysterectomy due to cervical intraepithelial neoplasia 3. Incidentally, ABC was found in the resected uterus. The tumor cells made small nests and infiltrated the cervical portion of the uterus. In the nests, glands, cribriform patterns with glandlike structures, and squamous differentiation were seen. Immunohistochemically, the glandlike structures were positive for laminin and type IV collagen. Ultrastructurally, the tumor cells had irregular nuclei, scanty cytoplasm, and cribriform patterns in which glandlike structures were covered with basal lamina. No myoepithelial differentiation of the tumor cells was seen. These findings suggest a similarity between adenoid basal carcinomas and adenoid cystic carcinomas. Furthermore, both tumors are considered to originate in the reserve cells of the uterine cervix. Because their outcomes are different, they should be distinguished from each other.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-2161
    Schlagwort(e): Key words Giant rice body ; Ultrastructure ; Immunohistochemistry ; Histogenesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Objective: To report four cases of rice bodies (RBs) showing remarkable size variations and discuss their pathogenesis. Design and patients: Based on analysis of the clinical data, we speculate on the pathogenesis of RBs using immunohistochemical and ultrastructural methods. The patients comprised three men and one woman, three with RBs in the subacromial bursae and one in the wrist synovial sheath, aged 28 (woman), 44, 50 and 81 (wrist) years, respectively. Results: There were no particular differences in clinical data among the patients. T2-weighted MR imaging was very useful for diagnosis of the RBs, allowing their clear delineation from the bursal fluid. The RBs consisted of a layered protein- aceous substance with vague targetoid cut surfaces. Much fibrin and a lesser amount of collagen fibers were recognized together with various mononuclear cells, which were few in number and predominantly T cells. The bursae and synovial sheath had multiple fibrinoid spheroids at the luminal surface. Conclusion: Fibrinoid nodular deposits probably became detached, forming the nuclei of RBs and growing to a giant RB 65 mm in diameter.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1432-2307
    Schlagwort(e): Key words Arteriogenesis ; Collateral vessels ; Ultrastructure ; Cell adhesion molecules
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Previous studies in the canine heart had shown that the growth of collateral arteries occurs via proliferative enlargement of pre-existing arteriolar connections (arteriogenesis). In the present study, we investigated the ultrastructure and molecular histology of growing and remodeling collateral arteries that develop after femoral artery occlusion in rabbits as a function of time from 2 h to 240 days after occlusion. Pre-existent arteriolar collaterals had a diameter of about 50 µm. They consisted of one to two layers of smooth muscle cells (SMCs) and were morphologically indistinguishable from normal arterioles. The stages of arteriogenesis consisted of arteriolar thinning, followed by transformation of SMCs from the contractile- into the proliferative- and synthetic phenotype. Endothelial cells (ECs) and SMCs proliferated, and SMCs migrated and formed a neo-intima. Intercellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1) showed early upregulation in ECs, which was accompanied by accumulation of blood-derived macrophages. Mitosis of ECs and SMCs started about 24 h after occlusion, whereas adhesion molecule expression and monocyte adhesion occurred as early as 12 h after occlusion, suggesting a role of monocytes in vascular cell proliferation. Treatment of rabbits with the pro-inflammatory cytokine MCP-1 increased monocyte adhesion and accelerated vascular remodeling. In vitro shear-stress experiments in cultured ECs revealed an increased phosphorylation of the focal contacts after 30 min and induction of ICAM-1 and VCAM-1 expression between 2 h and 6 h after shear onset, suggesting that shear stress may be the initiating event. We conclude that the process of arteriogenesis, which leads to the positive remodeling of an arteriole into an artery up to 12 times its original size, can be modified by modulators of inflammation.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 99 (2000), S. 310-316 
    ISSN: 1432-0533
    Schlagwort(e): Key words Ganglioglioma ; Ependymoma (tanycytic variant) ; Neurofibrillary tangle ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We studied a cystic ganglioglioma (GG) located in the right frontal lobe of the brain. Interestingly, the fibrillary spindle glial cells were often arranged in a fascicular pattern, and the generally uniform, round-to-oval delicate nuclei appeared to resemble those of ependymoma; and the neoplastic neurons often contained neurofibrillary tangles (NFTs). The glial component was positive for glial fibrillary acidic protein and occasionally contained granular or microvesicular structures positive for epithelial membrane antigen. Ultrastructural investigation revealed that the glial cells were ependymal in nature; intracytoplasmic lumina and intercellular microrosettes lined with cilia and microvilli, as well as long zonulae adherentes, were evident. In addition, chromogranin A-positive granular staining, neurosecretory-granule-like structures, and parallel arrays of microtubules were sometimes associated with the blood vessels. We considered the present case to be an unusual example of GG with an ependymoma, more precisely a tanycytic ependymoma, as the glial component; to our knowledge, the existence of ependymoma as the main glial component of this particular tumor has not been described before. The occurrence of NFTs, which has been reported in several cases of GG, was an additional, unusual feature.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 99 (2000), S. 214-218 
    ISSN: 1432-0533
    Schlagwort(e): Key words Eosinophilic inclusion body ; Inclusion ¶body ; Ependymoma ; Microlumina ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A study was undertaken to determine the pathological significance of previously unrecognized intracytoplasmic eosinophilic inclusions (IEIs) in ependymoma. The study group consisted of 58 ependymomas, all of which were pathologically characterized and graded according to the 1993 WHO classification. Electron microscopic studies were performed in 16 cases. The study showed that 33 (57%) ependymomas had IEIs and that in 8 cases these were abundant. Round and eosinophilic, their sizes varied from 10 μm to a tiny dot. Similar eosinophilic bodies were also observed between tumor cells. The inclusions were weakly PAS positive. On immunostains, IEIs were frequently positive for glial fibrillary acidic protein, less often for S-100 protein, and for epithelial membrane protein and CAM 5.2. They were negative for AE1/AE3, carcinoembryonic antigen and Ber-EP4. Ultrastructurally, IEIs represented intracytoplasmic lumens containing microvilli and cilia. These microlumina also frequently contained granulo-tubular materials. With reference to tumor subtypes, IEIs occurred most frequently in ordinary and clear cell ependymomas. IEIs were also present in 4 of 6 anaplastic ependymomas studied. In conclusion, IEIs represent microlumina and occur in more than a half of ependymomas including malignant examples. Their finding is a helpful diagnostic feature of ependymoma.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 201 (2000), S. 51-61 
    ISSN: 1432-0568
    Schlagwort(e): Key words Female prostate (Skene gland) ; Ultrastructure ; Secretory (luminal) cells ; Basal (reserve) cells ; Intermediary cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The predominant cells of female prostatic glands lining their lumen were found to be tall cylindrical secretory cells with short stubby microvilli, protuberances of the apical cytoplasm, and with bleb formation. Abundant secretory vacuoles and granules, rough endoplasmic reticulum, developed Golgi complexes and numerous mitochondria are characteristic of their active secretory configuration with apocrine (apical blebs) and merocrine (secretory vacuoles and granules) type of secretion. Basal (reserve) cells were seen to be located between the secretory (luminal) cells and the basement membrane. Their ground cytoplasm is dense with rough endoplasmic reticulum and mitochondria. Their nuclei, unlike those of secretory cells, possess more peripheral condensed chromatin, denser dispersed chromatin and sporadic nucleoli. Besides the two basic types of mature prostatic cells intermediary cells were also seen, located between the basal and secretory cells or in their close vicinity. Their cytoplasm exhibits numerous profiles of rough endoplasmic reticulum and free ribosomes. Secretory vacuoles and granules were mostly practically absent (type 1 intermediary cells) so that they resembled basal (reserve) cells. In some of them, however, as in secretory cells, such secretory elements do gradually appear (type 2 intermediary cells). The finding of intermediary cells in the lining of prostatic glands supports the role of basal (reserve) cells in the renewal of cells in glands of the female prostate. The first ultrastructural analysis of the normal female prostate performed by transmission electron microscopy showed that, as in the postpubertal male, the prostatic glands in the adult female display mature secretory and basal cells. The results of the presented study further corroborate the contemporary concept of the female prostate as a functional genitourinary organ.
    Materialart: Digitale Medien
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  • 13
    ISSN: 1432-0533
    Schlagwort(e): Key words Alzheimer disease ; Fibrillar amyloid-β ; Astrocytes ; Microglial cell ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Ultrastructural three-dimensional reconstruction of human classical plaques in different stages of development shows that microglial cells are the major factor driving plaque formation by fibrillar amyloid-β (Aβ) deposition. The amount of fibrillar Aβ released by microglial cells and the area of direct contact between amyloid and neuron determine the extent of dystrophic changes in neuronal processes and synapses. The volume of hypertrophic astrocytic processes separating fibrillar amyloid from neuron is a measure of the protective activation of astrocytes. On the bases of the volume of amyloid star, microglial cells, dystrophic neurites, and hypertrophic astrocytic processes, and spatial relationships between plaque components, three stages in classical plaque development have been distinguished: early, mature, and late. In early plaque, the leading pathology is fibrillar Aβ deposition by microglial cells with amyloid star formation. The mature plaque is characterized by a balance between amyloid production, neuronal dystrophy, and astrocyte hypertrophy. In late classical plaque, microglial cells retract and expose neuropil on direct contact with amyloid star, enhancing both dystrophic changes in neurons and hypertrophic changes in astrocytes. In late plaques, activation of astrocytes predominates. They degrade amyloid star and peripheral amyloid wisps. The effect of these changes is classical plaque degradation to fibrillar primitive and finally to nonfibrillar, diffuse-like plaques.
    Materialart: Digitale Medien
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  • 14
    ISSN: 1432-0533
    Schlagwort(e): Key words GM1-gangliosidosis ; Ultrastructure ; Electrospray ionisation tandem mass spectrometry ; Diagnosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The post-mortem diagnosis of lysosomal storage diseases can be confounded by the unavailability of suitable material. Here we report the diagnosis of GM1-gangliosidosis in a cross-bred dog, from which only formalin-fixed brain was available, by a combination of electron microscopy and the detection of elevated levels of GM1-ganglioside within the tissue using the novel technique of electrospray ionisation tandem mass spectrometry. Electron microscopic examination of ultrathin sections of resin-embedded tissue revealed cytoplasmic inclusions (membranous cytoplasmic and zebra bodies) in brain stem and cerebellar neurons that were characteristic of a gangliosidosis. Glycolipids were extracted from the fixed tissue and analysed by tandem mass spectrometry. Two major ions were detected, which corresponded to GM1 (d18:1–C18:0) and GM1 (d20:1–C18:0). Their identity was confirmed by comparison of their fragmentation patterns with those of authentic standards. The concentration of GM1 was approximately sixfold higher on a wet weight basis than in the brain of a normal control dog, confirming the diagnosis of GM1-gangliosidosis.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 436 (2000), S. 249-256 
    ISSN: 1432-2307
    Schlagwort(e): Key words Endothelial cells ; Cell culture ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The aim of the present work was to examine and compare the ultrastructure of bovine retinal endothelial cells (BRECs) in vitro during several passages in a medium selective for endothelial cells. The identity of the endothelial cells was confirmed immunohistochemically, up to the tenth passage. Changes in their ultrastructure in comparison to endothelial cells in vivo occurred at the onset of culturing and not progressively with repeated passages. The cultured BRECs show high metabolic activity in all passages. While retaining their identity as endothelial cells, they modify their lipid metabolism, so that lipids are stored. This change in lipid metabolism was induced by the medium.
    Materialart: Digitale Medien
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  • 16
    ISSN: 1432-2013
    Schlagwort(e): Key words Pineal organ ; Photoreceptor cells ; Ultrastructure ; Proteus anguinus ; Regressive evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We studied ultrastructure of the photoreceptor cells in the pineal organ of blind, depigmented, neotenic cave salamander, Proteus anguinus. Unlike in epigean vertebrates the outer segments of most photoreceptor cells consists of concentrically arranged lamellae, however; in few cells, the outer segments contain 7-9 plasma membrane disks. In both types of photoreceptor cells the outer segments enclose lumps of vesicles of different sizes. The photoreceptor cells of Proteus anguinus are similar to those in other cavernicolous fish species.
    Materialart: Digitale Medien
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  • 17
    ISSN: 1439-7609
    Schlagwort(e): Key words Septic arthritis ; Surface antigens ; Ultrastructure ; Burkholderia pseudomallei ; IEM
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Burkholderia pseudomallei is the causative agent of melioidosis, a disease that frequently runs a protracted course and is very difficult to eradicate. The mechanisms that this organism uses to escape from host defense mechanisms and antibiotics are not well understood. The aim of the study was to compare the morphological characteristics and surface antigen expression of B. pseudomallei in naturally infected human synovial tissues with the characteristics of bacteria grown in culture media. Immunoelectron microscopic study was performed in four synovial biopsies taken from four B. pseudomallei septic arthritis patients. Colonies of pathogenic B. pseudomallei collected from culture media were used as positive controls. Polyclonal antibody to whole cell B. pseudomallei was used as a primary antibody. Complete bacteria-like particles were demonstrated both extracellularly and intracellularly in all four synovial specimens. The intracytoplasmic location of B. pseudomallei and mononuclear phagosome containing microcolony-like structures were demonstrated. B. pseudomallei found in the synovial membrane samples were mostly atypical, with fewer cytoplasmic electron lucent granules. Immunogold staining of bacterial surface antigens was weaker than staining of positive controls. We demonstrated atypical forms of B. pseudomallei and evidence for suppression of its surface antigens in naturally infected human synovial tissues. This adaptation may help bacteria to survive despite host immune surveillance and treatment with antibiotics.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Oxidation of metals 53 (2000), S. 561-576 
    ISSN: 1573-4889
    Schlagwort(e): Fe–Cr–Al alloy ; oxidation ; molybdenum ; breakaway oxidation ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract Thin foils of Fe–20Cr–5Al alloys are susceptible to breakawayoxidation once the aluminum content of the substrate has fallen below somecritical value. The combined addition of 0.1 wt.% lanthanum and 0, 1, or 2wt% molybdenum has a beneficial effect on the high-temperature oxidation ofsuch foils. Lanthanum has the well-known reactive-element effect on adhesionof the protective alumina scale, thereby increasing the time to onset ofbreakaway oxidation, while, for alloys containing molybdenum, breakawayoxide spreads relatively slowly over the specimen in comparison to alloysthat contain no molybdenum. In particular, molybdenum-containing alloys areable to develop a protective Cr2O3 layer at the breakawayoxide–substrate interface. Conversely, molybdenum-free alloys form aninternal-oxide zone in the substrate adjacent to this interface, rather thana Cr2O3 layer, so breakaway oxide spreads rapidly. A martensitic phase isobserved in the substrate adjacent to the breakaway oxide formed on Fe–20Cr–5Al–La specimens, which means that theα-phase has transferred to the γ -phase at the temperature ofthe oxidation test (1150°C). Conversely, α-phase is retained inthe molybdenum-containing alloy, even after breakaway takes place, sincemolybdenum, which is a strong ferrite former, is enriched in the alloyadjacent to areas of breakaway oxide. The diffusion rate of chromium isslower in the γ than in the α-phase so a continuouschromium-rich oxide layer, which is effective in inhibiting breakawayoxide from spreading, cannot be established at the breakawayoxide–substrate interface for the molybdenum-free alloys.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Mycorrhiza 10 (2000), S. 15-21 
    ISSN: 1432-1890
    Schlagwort(e): Anthoceros punctatus ; Arbuscular mycorrhiza ; Bryophytes ; Glomus ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Glomus claroideum (Schenck & Smith emend. Walker & Vestberg) were investigated for ability to form arbuscular mycorrhiza-like symbioses with the hornwort Anthoceros punctatus (L.). Spores were transferred to a cellulose acetate filter on water agar and a small portion of an Anthoceros thallus was placed directly upon the spores. Light-microscope observations 20 days after inoculation revealed branched hyphae growing within the thallus. After 45 days, arbuscules and vesicles were studied by light- and electron-microscopy. After 60 days in water agar culture, the colonised Anthoceros thalli were transferred to a low-nutrient medium agar. Hyphae spread in the agar and newly formed spores were observed 5 weeks after the transfer. After 4 months, about 1000 spores were formed in each Petri dish. This is the first report of an experimentally established arbuscular mycorrhiza-like symbiosis between an identified fungus belonging to the Glomales and a bryophyte.
    Materialart: Digitale Medien
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  • 20
    ISSN: 1432-5233
    Schlagwort(e): Key words Streptozotocin ; Diabetes ; Ventricular myocyte ; Cardiac muscle ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Contractile dysfunctions have been demonstrated in different experimental models of diabetes which have similar characteristics to many of the abnormalities found in the clinical setting. Administration of streptozotocin (STZ) to young adult rats induces β-cell necrosis of the pancreas which gives rise to hypoinsulinaemia and hyperglycaemia, features which are also seen in untreated type 1 clinical diabetes. We have investigated the chronic effects of STZ-induced diabetes on contraction in rat ventricular myocytes and ultrastructure of cardiac muscle. Diabetes was induced in male Wistar rats (230–270 g) with a single injection of STZ (60 mg kg−1). At 2 and 10 months after STZ treatment, the amplitude of contraction was larger in diabetic compared to control myocytes. Time to peak contraction was significantly longer at 2 months but appeared to normalise at 10 months after STZ treatment. In contrast, time to half relaxation of contraction was not significantly different after 2 months but was significantly reduced at 10 months after STZ treatment compared to control. Transmission electron microscope examination of cardiac muscle showed that the ultrastructure of cardiac muscle, especially structures associated with contraction, were not greatly altered after STZ treatment. Sarcomere lengths were not significantly different in papillary or ventricular muscle at 4 or 8 months after STZ treatment compared to control. Our data provide evidence that morphological defects in contractile myofilaments and associated structures cannot explain contractile dysfunctions seen in ventricular myocytes from STZ-treated animals.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Transgenic research 9 (2000), S. 163-168 
    ISSN: 1573-9368
    Schlagwort(e): Hyoscyamus muticus ; particle bombardment ; transformation ; tropane alkaloids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We report an efficient whole plant transformation system for Hyoscyamus muticus, an important medicinal plant of the Solanaceous family. We developed a system using a plasmid carrying the nptII and gusA genes, which was delivered into leaf explants by particle bombardment. Ten percent of bombarded leaf explants formed kanamycin-resistant callus, from which putative transgenic plants were recovered. The nptII gene conferring kanamycin resistance was found to be incorporated into the genome of all transgenic plants screened. Over 50% of the kanamycin resistant plants showed strong expression of the non-selected gusA gene. The majority of transgenic plants reached maturity, could be self pollinated, and produced fertile seed. A simple and efficient whole plant transformation system for this medicinal plant is an important step in furthering our understanding of tropane alkaloid production in plants.
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  • 22
    ISSN: 1573-9368
    Schlagwort(e): inheritance ; Rubisco small subunit promoters ; sonication ; sulphur nutrition ; sunflower albumin ; transformation ; white clover
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract With the aim of increasing the rumen-protected level of the sulphur amino acids cysteine and methionine in Trifolium repens, we introduced the coding sequence of the sunflower seed albumin (SSA) into T. repens by Agrobacterium tumefaciens-mediated transformation. The SSA gene was modified such that the protein would be localised to the endoplasmic reticulum (ER). Four different T-DNA constructions all containing the SSA gene driven by either the promoter of a gene encoding the small subunit of ribulose bisphosphate carboxylase (Rubisco) from Arabidopsis thaliana (A ssu), the promoter of the gene encoding the small subunit of Rubisco of Medicago sativa (L ssu), or the Cauliflower Mosaic Virus 35S promoter (CaMV35S), were transferred to T. repens cv. Haifa. Transgenic T 0-plants and inter-transgenic hybrids were analysed for the level of SSA accumulation in the leaves by western blotting. The highest observed level of SSA accumulation was 0.1% of total extractable leaf protein. We observed that the promoter had a substantive effect on the level of SSA accumulation with A ssu〉CaMV35S〉L ssu. Results from the inter-transgenic hybrids showed that the capacity to synthesise SSA was inherited. However the level of SSA accumulation in the leaves generally appears not to be additive with extra transgenic loci. During this work, we attempted to improve the efficiency of A. tumefaciens-mediated transformation of T. repens using the SAAT-method (Sonication Assisted Agrobacterium-mediated Transformation) on cotyledons of T. repens. T-DNA transfer was in general not enhanced by sonication compared to traditional A. tumefaciens-mediated transformation. Furthermore, Southern blot analyses of plants regenerated from the same cotyledon after A. tumefaciens treatment and under selection, indicated that multiple shoots were usually derived from the same transformation event. We concluded from these results that only one plant from each A. tumefaciens-treated cotyledon should be taken to avoid transgenic clones.
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Transgenic research 9 (2000), S. 405-415 
    ISSN: 1573-9368
    Schlagwort(e): Manihot esculenta ; transformation ; Agrobacterium tumefaciens ; mannose ; hygromycin ; selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In order to improve the efficiency of cassava (Manihot esculenta Crantz) transformation, two different selection systems were assessed, a positive one based on the use of mannose as the selective agent, and a negative one based on hygromycin resistance encoded by an intron-containing hph gene. Transgenic plants selected on mannose or hygromycin were regenerated for the first time from embryogenic suspensions cocultivated with Agrobacterium. After the initial selection using mannose and hygromycin, 82.6% and 100% of the respective developing embryogenic callus lines were transgenic. A system allowing plant regeneration from only transgenic lines was designed by combining chemical selection with histochemical GUS assays. In total, 12 morphologically normal transgenic plant lines were produced, five using mannose and seven using hygromycin. The stable integration of the transgenes into the nuclear genome was verified using PCR and Southern analysis. RT-PCR and northern analyses confirmed the transgene expression in the regenerated plants. A rooting test on mannose containing medium was developed as an alternative to GUS assays in order to eliminate escapes from the positive selection system. Our results show that transgenic cassava plants can be obtained by using either antibiotic resistance genes that are not expressed in the micro-organisms or an antibiotic-free positive selection system.
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Transgenic research 9 (2000), S. 471-486 
    ISSN: 1573-9368
    Schlagwort(e): Arabidopsis thaliana ; Agrobacterium tumefaciens ; floral spray ; SOD ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In this study, floral spray and floral dip were used to replace the vacuum step in the Agrobacterium-mediated transformation of a superoxide dismutase (SOD) gene into Arabidopsis. The transgene was constructed by using a CaMV 35S promoter to drive a rice cytosolic CuZnSOD coding sequence in Arabidopsis. The transgene construct was developed in binary vectors and mobilized into Agrobacterium. When Arabidopsis plants started to initiate flower buds, the primary inflorescence shoots were removed and then transformed by floral spray or floral dip. More than 300 transgenic plants were generated to assess the feasibility of floral spray used in the in planta transformation. The result indicates that the floral spray method of Agrobacterium can achieve rates of in planta transformation comparable to the vacuum-infiltration and floral dip methods. The floral spray method opens up the possibility of in planta transformation of plant species which are too large for dipping or vacuum infiltration.
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  • 25
    ISSN: 1615-6102
    Schlagwort(e): Arabidopsis thaliana ; Cryopreservation ; Dehydration ; Thermal analysis ; Sucrose ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Arabidopsis thaliana suspension cells were preserved in liquid nitrogen for over three years, using embedding of cells in calcium-alginate prior to subculture in sucrose-enriched medium, air-drying, and direct quenching in liquid nitrogen. Survival of cells reached 34%, yielding regrowth at the surface of all cryopreserved beads in less than 7 days. Following pretreatment and dehydration, the water content dropped from 2300% to 34% with respect to dry weight. Differential scanning calorimetry showed that glass transition occurred on cooling, followed by a slight crystallization event on rewarming. The survival of cells was independent of the cooling rate. The tolerance of the acute dehydration step increased progressively with sucrose pretreatment duration, indicating the requirement for adaptative cellular alterations. Ultrastructural studies revealed several changes in cells after sucrose pretreatment prolonged from 1 to 7 days: reversal of the initially plasmolyzed state, microvacuolation, numerous autophagic structures, scarcity of ribosomes, increase in number and size of starch grains. No cell division seemed to occur during this period. After air-drying and after a freeze-thaw cycle, followed by 24 h rehydration, regenerating cells had recovered a high level of ultrastructural organization and contained numerous polysomes suggesting an intense metabolic activity. Trehalose, a cryoprotective disaccharide not considered to be a metabolic substrate, yielded only 70% regrowth after freezing. Biochemical analysis showed that soluble sugars accumulated during the pretreatment, essentially sucrose or trehalose; the monosaccharide content also increased. In the light of these results, the action of sucrose in inducing freezing tolerance is discussed.
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  • 26
    ISSN: 1615-6102
    Schlagwort(e): Beta vulgaris ; Cyst nematodes ; Histology ; Resistance mechanism ; Syncytium ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Using susceptible and resistant sugar beet lines, comparative analyses of root histology and ultrastructure were made during invasion by nematodes and the induction and formation of specific feeding structures (syncytia).The resistant line carried the resistance geneHs1pro−1.Nematodes were able to invade and induce functional syncytia in roots of resistant and susceptible lines. However, syncytia in resistant roots were smaller and less hypertrophied. The vacuolar system of syncytia in susceptible plants contained many small vacuoles. In resistant plants vacuoles were larger but less numerous. Smooth endoplasmic reticulum prevailed in syncytial protoplasts of susceptible plants, whereas almost only rough endoplasmic reticulum occurred in syncytia in resistant plants. The most conspicuous and hitherto undescribed trait of syncytia in resistant roots was the initial appearance of loose, and later compact, aggregations of the endomembrane system which composed most of the endoplasmicreticulum system of syncytia at later stages. Syncytia in resistant plants usually degraded before the nematodes reached their adult stage. The appearance of membrane aggregations and the other resistance-specific features are discussed in relation to their possible effects on syncytium function and role in nematode resistance.
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Protoplasma 211 (2000), S. 94-102 
    ISSN: 1615-6102
    Schlagwort(e): Androgenesis ; Embryogenesis ; Microspore culture ; Pollen ; Ultrastructure ; Wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We have made a detailed cytological examination of the development of wheat embryoids, monitoring their initial divisions from two to ten cells by both light and electron microscopy. According to our observations the first embryogenic division is symmetrical. After the androgenesis induction treatment, there is a decrease in ribosome population with cells that have inactive nucleoli made up almost exclusively of a dense fibrillar component. This population is restored after initial embryogenic divisions. During the initial divisions the embryogenic pollen grains do not appear to change in size and the pollen wall remains intact. The exine undergoes no modification but the intine thickens, and we have observed that the thickness of the intine can be used as a cytological marker of androgenesis. The walls separating the cells obtained after embryogenic division contained numerous plasmodesmata. The beginnings of embryo polarization and cell differentiation could be made out in the very early pollen embryoids.
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  • 28
    ISSN: 1573-4986
    Schlagwort(e): Cancer ; caveolae ; caveolin ; cholesterol ; glucosylceramide ; multidrug resistance ; rafts ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The carcinogenic process involves a complex series of genetic and biochemical changes that enables transformed cells to proliferate, migrate to secondary sites and, in some cases, acquire mechanisms that make cancer cells resistant to chemotherapy. This phenomenon in its most common form is known as multidrug resistance (MDR). It is usually mediated by overexpression of P-glycoprotein (P-gp) or other plasma membrane ATPases that export cytotoxic drugs used in chemotherapy, thereby reducing their efficacy. However, additional adaptive changes are likely to be required in order to confer a full MDR phenotype. Recent studies have shown that acquisition of MDR is accompanied by up-regulation of lipids and proteins that constitute lipid rafts and caveolar membranes, notably glucosylceramide and caveolin. These changes may be related to the fact that in MDR cells a significant fraction of cellular P-gp is associated with caveolin-rich membrane domains, they may be involved in drug transport and they could have an impact on drug-induced apoptosis and on the phenotypic transformation of MDR cancer cells.
    Materialart: Digitale Medien
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  • 29
    ISSN: 1572-9788
    Schlagwort(e): Choline oxidase ; glycinebetaine ; transformation ; Brassica juncea ; salt stress
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The codA gene for biosynthesis of glycinebetaine from Arthrobacter globiformis was used for transforming Brassica juncea cv. Pusa Jaikisan (which lack any means to synthesize glycinebetaine) through Agrobacterium mediated transformation. The stable insertion of the codA gene in the shoots obtained on medium with kanamycin and hygromycin was confirmed by PCR analysis of the nptII gene. Southern hybridization with a codA probe further demonstrated its successful integration. Immunoblot analysis revealed the presence of choline oxidase demonstrating that the bacterial codA gene had been successfully transcribed and translated. The seeds of transgenic lines showed enhanced capacity to germinate under salt stress as compared to that of the wild type. Further, the seedlings of transgenic plants that expressed codA gene showed significantly higher growth than that of the wild type under salt stress conditions. These results demonstrated that the introduction of a biosynthetic pathway for glycinebetaine into Brassica juncea significantly enhanced their salt tolerance. Hence, homozygous genotypes of selected transformed lines can be exploited for improving the salt tolerance of the desirable cultivars of Brassica juncea through breeding programmes.
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  • 30
    ISSN: 1572-9788
    Schlagwort(e): antisense DNA ; co-transformation ; nucleocapsid gene ; pathogen-derived resistance ; somatic embryogenesis ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Peanut (Arachis hypogaea L.) lines transgenic for the antisense nucleocapsid (N) gene of a Tomato spotted wilt virus (TSWV) strain isolated from peanut were generated by microprojectile-mediated transformation of repetitive somatic embryos of cultivars VC1 and AT120. The selectable marker (hygromycin resistance) and the N gene were on separate plasmids. A total of 207 VC1 and 120 AT120 hygromycin-resistant lines were produced. Of all the VC1 plants recovered 71% were cotransformed with the N gene (N+), but all plants were sterile. For AT120, 48 of the transgenic cell lines converted into plants. Polymerase chain reaction (PCR) screening showed 15 of the lines were transgenic for the N gene (N+), and two of these lines were fertile. A field test was conducted in 1998 at Ashburn, GA, using seeds from each fertile line, along with segregated and non-transgenic controls. Plants from four randomly selected field plots were examined for symptoms and analyzed by double-antibody sandwich enzyme-linked immunoabsorbent assay and PCR at 10 and 14 weeks after planting. At 14 weeks, 76% of the N+ plants were symptomless, while 2% were severely symptomatic or dead. In contrast, only 42% of the plants lacking the N gene were symptomless and 50% were severely symptomatic or dead. Northern blot analysis of selected field-resistant plants detected transgene RNA, and the transcript level appeared undiminished after viral exposure.
    Materialart: Digitale Medien
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  • 31
    ISSN: 1572-9788
    Schlagwort(e): bar ; cry3A ; Eucalyptus ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Transgenic Eucalyptus camaldulensis containing both the insecticidal cry3A gene and the bar gene (conferring tolerance to the herbicide glufosinate ammonium) have been produced by Agrobacterium tumefaciens-mediated transformation of seedling explants. Transgenic plants from two lines tested were resistant to first instars of chrysomelid beetles that are important pests of commercial Australian eucalypt plantations. Both lines also exhibit tolerance to the broad-spectrum herbicide Liberty® at 6 l/ha (1.2 kg active ingredient per hectare), twice the field application rate. Transgenic insect- and herbicide-resistant eucalypts like these are likely to provide better insect and weed control options in plantations, particularly during the vulnerable establishment phase, provided that any adverse ecological impacts of releasing transgenic trees into the environment can be assessed and minimized.
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  • 32
    ISSN: 1572-9788
    Schlagwort(e): choline oxidase ; glycinebetaine ; Japanese persimmon ; salt tolerance ; transformation ; woody plant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This report describes the first successful genetic engineering of tolerance to salt in an agriculturally important species of woody plants by Agrobacterium-mediated transformation with the codA gene of Arthrobacter globiformis. This gene encodes choline oxidase, which catalyzes the oxidation of choline to glycinebetaine. The binary plasmid vector pGC95.091, containing a kanamycin-resistance gene (nptII), a gene for β-glucuronidase (gusA) and the codA gene in its T-DNA region, was used with a disarmed strain of Agrobacterium tumefaciens, EHA101, to transform Japanese persimmon (Diospyros kaki Thunb. `Jiro') by the leaf disk transformation method. The pRS95.101 plasmid that included only nptII and gusA in the T-DNA region was used as a control. We selected eight transgenic lines with one or two copies of the T-DNA after transformation with pGC95.091 (PC lines) and three lines after transformation with pRS95.101 (PR lines). The eight PC lines produced choline oxidase and glycinebetaine whereas neither was found in untransformed `Jiro' and in the control PR lines. Transgenic plants grew normally, resembling wild-type plants both in vitro and ex vitro. The activity of photosystem II in leaves of the transgenic Japanese persimmon plants under NaCl stress was determined in terms of the ratio of the variable (F v) to the maximum (F m) fluorescence of chlorophyll (F v/F m). The rate of decline in (F v/F m under NaCl stress was lower in the PC lines than in the control PR lines. These results demonstrated that genetic engineering of Japanese persimmon, which allowed it to accumulate glycinebetaine, enhanced the tolerance to salt stress of this plant.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Molecular breeding 6 (2000), S. 185-194 
    ISSN: 1572-9788
    Schlagwort(e): Agrobacterium ; transformation ; pea ; Pisum sativum L. ; PCR analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Factors influencing the efficiency of Agrobacterium-mediated transformation of pea were tested using highly efficient, direct regeneration system. The virulence of three Agrobacterium strains (octopine LBA 4404, nopaline C58C1 and succinamopine, hypervirulent EHA 105) clearly varied giving 1 transgenic plant per 100 explants for LBA 4404, 2.2 for C58C1 and 8.2 for EHA 105. To test the efficacy of selection agents we used the hypervirulent EHA 105 strain carrying pGPTV binary vector with one of four different selection genes: nptII, hpt, dhfr or bar. The mean number of transgenic, kanamycin-resistant plants for two cultivars tested was 4.2 per 100 explants and was slightly higher than the number of phosphinothricin-resistant plants (3.6 plants per 100 explants). The proportion of transgenics among kanamycin-selected plants was also higher than among phosphinothricin-resistant plants (35% and 28% respectively). There was no regeneration on hygromycin or methotrexate media (transformation with hpt and dhfr genes). Acetosyringone had no apparent influence on efficiency of transformation with hypervirulent EHA 105 strain, however it did affect the rate of transformation when moderately virulent C58C1 was used. Recovery of transgenic plants was enhanced after application of 5-azacytidine. The presence of integrated T-DNA was checked by PCR and confirmed by Southern hybridization. T-DNA was stably transmitted to the next generation.
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  • 34
    ISSN: 1572-9788
    Schlagwort(e): heterologous protein accumulation ; phytate phosphorus digestibility ; phytase ; phytic acid ; transformation ; Triticum aestivum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The Aspergillus niger phytase-encoding gene (phyA) has been constitutively expressed in wheat. Transgenic wheat lines were generated by microprojectile bombardment of immature embryos, using the bar-Bialaphos selection system. The bar and the phyA gene expression were controlled by the maize ubiquitin-1 promoter. To ensure secretion and glycosylation of the microbial phytase, an expression cassette was designed (Ubi-SP-Phy) where an α-amylase signal peptide sequence was inserted between the promoter and the phytase coding region. A similar cassette was constructed without the signal peptide sequence (Ubi-Phy). Five lines of fertile wheat transformed with the Ubi-SP-Phy were generated and two lines with the Ubi-Phy construct. The inheritance of the phyA gene was monitored through three generations. Western blotting of leaf and seed derived protein revealed the presence of an immunoreacting polypeptide of the size expected for the Aspergillus phytase. Up to 25 days after pollination, the heterologous phytase was exclusively present in the pericarp-seed coat-aleurone fraction. Thereafter, it accumulated in the endosperm in amounts exceeding that found in the seed coat and aleurone. The phyA mRNA and derived protein could at no stage be detected in the embryo. The Ubi-SP-Phy transgenic seeds exhibited up to 4-fold increase of phytase activity while up to 56% increase was found in Ubi-Phy plants. It is concluded that a functional Aspergillus phytase can be produced in significant amounts in wheat grains. This may be of relevance for improving the phytate-phosphorus digestibility when wheat grains are used for non-ruminant animal feed.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Pituitary 3 (2000), S. 117-122 
    ISSN: 1573-7403
    Schlagwort(e): Cushing's disease ; silent ; pituitary ; tumour ; macroadenoma ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Silent pituitary adenomas occur in 25–40% of all clinically apparent pituitary tumours. However, the subsequent development of florid Cushing's disease in a patient with a previous non-functioning tumour is extremely rare. We describe a 47 year-old woman presenting initially with a large, invasive and recurrent, non-functioning pituitary tumour. Histopathologic study of the initial tissue did not stain for any hormones. Six years after the initial presentation, she manifested florid ACTH dependent Cushing's syndrome. A recurrent invasive pituitary macroadenoma necessitated a third transphenoidal surgery. The resected specimen, in this instance, revealed positive staining for ACTH, FSH, prolactin, and growth hormone on immunocytochemistry. An incomplete response to surgical, radiation and medical therapy necessitated a bilateral adrenalectomy to control the hypercortisolism, which resulted in remarkable clinical improvement. We also review five previous case reports from the revision literature of similar transformations from non-secreting pituitary adenomas to Cushing's disease. This subset of patients may represent yet another entity in the widening spectrum of Cushing's syndrome.
    Materialart: Digitale Medien
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  • 36
    ISSN: 1615-6102
    Schlagwort(e): Glutathione ; Root ; Chromosomal aberration ; Ultrastructure ; Picea abies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Young spruce seedlings (Picea abies [L.] Karst.) grown in hydroponic culture were exposed to three different concentrations (50,100, and 500 μM) of reduced glutathione for 24 h. These physiologically relevant concentrations of glutathione had a multiple effect on the investigated tissue. Feeding of glutathione to roots increased the concentrations of thiols (glutathione, cysteine, and γ-glutamyl-cysteine) in roots, decreased the rate of cell divisions, induced mitotic abnormalities, and affected the cell ultrastructure. Electron micrographs showed effects such as advanced vacuolation, dilated rough-endoplasmic-reticulum cisternae, and separations of the plasma membrane from the cell wall.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Systemic practice and action research 13 (2000), S. 475-501 
    ISSN: 1573-9295
    Schlagwort(e): reflection ; transformation ; self-society dynamics ; critical systems thinking ; systemic intervention ; critical self-reflection ; ideology-critique ; critical appreciation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Sociologie
    Notizen: Abstract This paper sets out to uncover some relationships between reflection, discourse and action. By challenging and synthesizing some polemical arguments concerning the creation, maintenance, and transformation of self and society, a model of self-society dynamics that operates through reflection, discourse, and action is developed. The model of self-society dynamics brings together aspects of self-reflection and ideology-critique (explored in the paper), which it is suggested are required for any intervention (transformative action) to be grounded in locally meaningful ways. By creating a dialog community in which self- and group assumptions can be subjected to validation through discourse, it is proposed that a dynamic balance between individual needs and broader societal aims may be achieved. If individuals can be open to such discourse (i.e., they can become critically self-reflective), then it is argued that possibilities for achieving sustainable change will be significantly enhanced.
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  • 38
    ISSN: 1573-5060
    Schlagwort(e): conifers ; salgareño pine ; tissue culture ; transformation ; transient gene expression ; uidA expression ; vir gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Cotyledons from dissected sterile embryos of salgareño pine (Pinus nigra Arn. ssp. salzmannii (Dunal) Franco) were inoculated with different disarmed Agrobacterium tumefaciens strains harbouring the binary vector p35SGUSint. The transient expression of a β-glucuronidase gene (uidA) was studied, using a histochemical staining procedure. Nineteen days after inoculation, the activity of β-glucuronidase was detected in epidermal and subepidermal layers of cotyledonary explants. The EHA105 strain harbouring a disarmed agropine-type Ti-plasmid (pTiBO542) was the most effective for gene transfer of the uidA gene. The effects of exudates and extracts from 0-day-old embryos on induction of vir gene expression in A. tumefaciens were also examined. The results of this study showed that salgarño pine embryo exudates contain a substance(s) that induce vir gene expression, in similar way to that observed with 100 μM acetosyringone (AS).All these findings suggest that T-DNA processing and transfer might take place when Agrobacterium infects suitable tissues of salgareño pine.
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  • 39
    ISSN: 1573-5060
    Schlagwort(e): cell suspension ; monocotyledon ; selection ; somatic embryogenesis ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The successful application of plant biotechnology to Alstroemeria improvement will largely depend on the availability of an efficient regeneration/transformation system. Regeneration in Alstroemeria is accomplished from nodular embryogenic callus initiated from zygotic embryos. Histological studies of embryogenic callus initiation from 4-weeks old cultured ovules revealed that the outermost layers of the protoderm of the embryogenic nodules divided to form either a new nodule or aproembryo. Transient gene expression after particle bombardment of nodular embryogenic callus was optimized using DNA of pAHC25. The highest β-glucuronidase expression was found when the GUS gene was under control of the maize ubiquitin promoter, the target tissue was placed 5 cm below the microcarrier launch assembly and when the rupture disc-breakage point was between 650–900 psi. Kanamycin blocked regeneration of somatic embryos, however, did not block growth of nodular embryogenic callus. With phosphinothricin both callus growth and regeneration were blocked. Bombardment of nodular embryogenic callus with DNA of pAHC25 combined with selection on medium containing phosphinothricin resulted in putative transgenic chimeric. Friable calli were selected from nodular embryogenic callus and used to initiate suspensions. These cell suspensions were subjected to transformation by particle bombardment using DNA of pAHC25 and resulted in a stable transformed friable callus line after selection based on luciferase activity. Even after 2 years of maintenance this callus line was luciferase positive and the Polymerase Chain Reaction analysis demonstrated the presence of the introduced gene in this friable callus line.
    Materialart: Digitale Medien
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  • 40
    ISSN: 1573-5087
    Schlagwort(e): alfalfa ; cell division cycle ; somatic embryogenesis ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Two simple, rapid and efficient protocols for theregeneration of transformed tetraploid lines ofalfalfa (Medicago falcata L.) have beendeveloped and compared. Leaf explants fromembryogenic lines 47/1-150 and 47/1-5 were inoculatedwith Agrobacterium tumefaciens containingconstructs carrying the nptII selectable markergene and promoter:gusA gene fusions under thecontrol of the CaMV 35S or Arabidopsis cdc2a,CycB1 and CycA2 promoters. In the firstregeneration system (the MSH system), inoculated leafexplants were incubated on MS medium supplemented with2,4-D and kinetin and then subcultured onto plantgrowth regulator-free MS medium in order to inducedirect somatic embryogenesis. In the secondregeneration system (the B5h system), the inoculatedexplants were incubated on B5h medium to induceindirect production of somatic embryos viaembryogenic callus. In both systems, an effectivekanamycin selection regime was employed and wasmaintained when the embryos were subcultured onto arecovery medium (Boi2Y) to promote further embryodevelopment. The use of Boi2Y medium was particularlyimportant for shortening the regeneration time andpromoting a higher frequency of healthy plantletproduction from the somatic embryos. The maturesomatic embryos were finally transferred to plantgrowth regulator-free MS medium for plantletformation. Transgenic plantlets were produced within10–14 weeks in the MSH system and 12–16 weeks in theB5h system. The MSH system appears to be the fastesttransformation system reported for leguminous speciesto date. Confirmation of transformation was obtainedusing a re-callusing assay on kanamycin and subsequentSouthern blot hybridisation and PCR analysis. Theability to induce expression of GUS activity in leafexplants containing the cell division cycle genepromoter:gusA constructs by 2,4-D treatment alsoproved to be a reliable indicator of transformation.
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  • 41
    ISSN: 1573-5028
    Schlagwort(e): Agrobacterium tumefaciens ; sorghum ; transformation ; transgenic plants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Agrobacterium tumefaciens was used to genetically transform sorghum. Immature embryos of a public (P898012) and a commercial line (PHI391) of sorghum were used as the target explants. The Agrobacterium strain used was LBA4404 carrying a `Super-binary' vector with a bar gene as a selectable marker for herbicide resistance in the plant cells. A series of parameter tests was used to establish a baseline for conditions to be used in stable transformation experiments. A number of different transformation conditions were tested and a total of 131 stably transformed events were produced from 6175 embryos in these two sorghum lines. Statistical analysis showed that the source of the embryos had a very significant impact on transformation efficiency, with field-grown embryos producing a higher transformation frequency than greenhouse-grown embryos. Southern blot analysis of DNA from leaf tissues of T0 plants confirmed the integration of the T-DNA into the sorghum genome. Mendelian segregation in the T1 generation was confirmed by herbicide resistance screening. This is the first report of successful use of Agrobacterium for production of stably transformed sorghum plants. The Agrobacterium method we used yields a higher frequency of stable transformation that other methods reported previously.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    GeoJournal 52 (2000), S. 253-262 
    ISSN: 1572-9893
    Schlagwort(e): map sheets ; GIS ; seamless spatial database ; transformation ; computational procedure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geographie
    Notizen: Abstract Map sheets have been often used as a basic spatial unit for managing spatial data produced from paper maps. This often results in incompatibility between adjacent map sheets, because spatial objects do not cross the boundaries smoothly and even the boundaries themselves do not match their neighbors exactly. To solve the problem this paper proposes a computational procedure for joining separate map sheets to obtain seamless spatial data. Line objects digitized separately in different map sheets are considered, which are frequently used to represent road networks, gas pipelines, and boundaries of polygon objects. The procedure consists of three steps: (1) extraction of end nodes, (2) detection of matching nodes, and (3) transformation of the map sheet. Each step goes interactively so that unexpected errors can be avoided by human observation. To test the validity of the procedure, map sheets are combined containing the road network data of Tokyo 23-ku area, Japan.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    GeoJournal 50 (2000), S. 97-100 
    ISSN: 1572-9893
    Schlagwort(e): disease ; health ; morbidity ; mortality ; pollution ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geographie
    Notizen: Abstract In general, the health of Poles improved markedly in the thirty years after the Second World War, but there was some deterioration after 1989 before improvement resumed. Only in the case of cancer is there an upward trend and so Poles are now healthier than they have been at any time in the past. However there are sharp regional variations well exemplified by the incidence of tuberculosis, where there appears to be some correlation with poorer housing and atmospheric pollution. High death rates in Lodz (consistently the highest in the country at the voivodship level between 1989 and 1996), may also be linked with environmental pollution as well as the ageing of the population. Variations between town and country are small, but Poland shows up in a poor light when compared with other European countries. These are important issues for the administration and financing of the welfare services.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    GeoJournal 50 (2000), S. 151-155 
    ISSN: 1572-9893
    Schlagwort(e): demography ; experts ; rural ; Romania ; rural development ; social issues ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geographie
    Notizen: Abstract There is no standard model of transformation for post- socialist countries and each country encounters specific problems rooted in the geographical characteristics of the areas concerned. The human resources are of the greatest importance because it really matters how people (especially the decision-makers) perceive system change and continually reformulate their expectations and strategies; so investigations into the views of people caught up in the transformation can provide a deeper understanding of the background to structural change. Working the national, regional level and local levels in Romania, experts were asked to consider the advantages and disadvantages arising out of the transformation, the most important problems and constraints for future rural development and the policies needed. The paper examines the responses on demographic and social issues. It emerges the most detailed responses were supplied by local-level representatives while respondents at the regional level steered a middle course between the need to address local problems and the prime importance of stimulating the Romanian economy so as to generate resources for welfare programmes (with the latter issue the overriding concern of interviewees at national level). There was general agreement on the importance of foreign investment and European integration for economic development, with local actors taking only small steps in line with the existing opportunities.
    Materialart: Digitale Medien
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  • 45
    ISSN: 1573-5060
    Schlagwort(e): Barley ; Hordeum vulgare ; transformation ; particle bombardment ; particle gun
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Immature embryos of the spring barley variety GoldenPromise, were bombarded with three different particledelivery systems and both transient and stabletransformation examined. In addition, a range oftechniques for the preparation of the DNA coated goldparticles was examined. Fertile transgenic barleyplants were obtained using three particle preparationtechniques which differed in the amount of gold andDNA used for each bombardment. However, only one ofthe particle delivery systems, the PDS 1000/He device,appeared to be effective in yielding transformedbarley plants.
    Materialart: Digitale Medien
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  • 46
    ISSN: 1573-6776
    Schlagwort(e): casein hydrolysate ; Coleus forskohlii ; forskolin ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Casein hydrolysate at 2.0 g l−1 significantly enhanced forskolin content (2.3 mg g−1 cell dry wt) in a rhizogenic tumourous line, GCO-RCH-2 of Coleus forskohlii. In rooty teratoma line, RC-ST-2/4, forskolin content enhanced to 1.7 mg g−1 cell dry wt in presence of 2.5 g l−1 casein hydrolysate. Unlike untransformed calli and rhizogenic/root cultures, all the forskolin yielding transformed cultures of C. forskohlii have been maintained for over 5 years.
    Materialart: Digitale Medien
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Applied mathematics and mechanics 21 (2000), S. 1423-1431 
    ISSN: 1573-2754
    Schlagwort(e): nonlinear differential equations ; transformation ; algorithm ; analytical solution ; O175.29
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Mathematik , Physik
    Notizen: Abstract The idea of AC=BD was applied to solve the nonlinear differential equations. Suppose that Au=0 is a given equation to be solved and Dv=0 is an equation to be easily solved. If the transformation u=Cv is obtained so that v satisfies Dv=0, then the solutions for Au=0 can be found. In order to illustrate this approach, several examples about the transformation C are given.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Neurological sciences 21 (2000), S. S27 
    ISSN: 1590-3478
    Schlagwort(e): Key words Neuronal ceroid lipofuscinoses ; Lipopigments ; Ultrastructure ; Classification ; Genes ; Neuronal loss
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Morphological aspects of the neuronal ceroid lipofuscinoses (NCL) encompass two main features: loss of nerve cells and accumulation of autofluorescent lipopigments within cellular compartments. The former requires histology and morphometry for assessment, while the latter necessitates fluorescence microscopy, electron microscopy, and immunohistochemistry. Accumulation of lipopigments is widespread throughout the central nervous system and extracerebrally. The latter feature enables diagnosis of NCL and its clinical subtype. Loss of neurons is most pronounced in cerebral and cerebellar cortices, in early childhood forms. In subcortical grey matter and in later-onset forms, juvenile and adult NCL, reduction in neurons and possible preceding dendritic pathology may only correctly be ascertained by age-matched, controlled morphometric investigations which, to date, have not yet completely assessed subcortical neuronal damage. Presently, clinical and morphological evaluations are mandatory for genetic analysis, genetic counselling, and prenatal diagnosis, the latter often being based on combined genetic and morphological studies.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    World journal of microbiology and biotechnology 16 (2000), S. 177-182 
    ISSN: 1573-0972
    Schlagwort(e): Conjugation ; metal resistance ; plasmid DNA ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Heavy metal concentrations in soil treated with industrial wastewater of Aligarh City (U.P.), India were determined. The analysis of test samples revealed high levels of Fe, Zn, Ni and Cu. A total of 45 Pseudomonas spp. were isolated from soil and were characterized on the basis of morphological, cultural and biochemical characteristics. MICs of Hg2+, Cd2+, Cu2+, Cr3+, and Zn2+ for each isolate were determined. Eighty percent of the strains isolated from soil harboured resistance to copper, whereas 73.3% of the isolates exhibited resistance to cadmium, 71.1% to chromium and zinc and 48.8% to mercury. A maximum MIC of 200 μg/ml for mercury and 1600 μg/ml for other metals was observed. Metal resistance was found to be plasmid mediated as evidenced by transformation studies. Further, the transmissible nature of chromium resistance was confirmed by conjugation. Agarose gel electrophoresis using the miniprep method for plasmid isolation revealed that these isolates harboured plasmids of molecular weights (45 & 47 kb) using EcoRI and HindIII digests of λDNA and undigested λDNA as standard markers.
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied psychoanalytic studies 2 (2000), S. 109-115 
    ISSN: 1573-3459
    Schlagwort(e): James Joyce ; “The Dead” ; fiction ; reading ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Psychologie
    Notizen: Abstract The author offers a personal reading of James Joyce's “The Dead.” She focuses on how the sounds of the language are used to portray the main character's deadness and his beginning to come to life once the barriers to inner self and self-knowledge are broken.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Chemistry of natural compounds 36 (2000), S. 137-139 
    ISSN: 1573-8388
    Schlagwort(e): 1,1′,6,6′,7,7′-hexahydroxy-3,3′-dimethyl-5,5′-diisopropyl-2,2′-dinaphthylidene-8,8′-dibarbituric acid ; transformation ; DMSO
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Transformations of 1,1′,6,6′,7,7′-hexahydroxy-3,3′-dimethyl-5,5′-diisopropyl-2,2′-dinaphthylidene-8,8′-dibarbituric acid (batridene) in DMSO are studied.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Brain tumor pathology 17 (2000), S. 15-19 
    ISSN: 1861-387X
    Schlagwort(e): Hemangioblastoma ; Supratentorial tumor ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Supratentorial hemangioblastomas are rarely seen, especially in children and adolescents. We report the case of a 17-year-old male with supratentorial hemangioblastoma. Neuroimaging demonstrated a cystic lesion within the right parietal lobe. Systemic examination revealed no abnormality. The lesion was not attached to the dura and was not associated with von Hippel-Lindau disease. It was very difficult to confirm the final diagnosis of this case, in spite of extensive examination by light microscopy, immunohistochemical studies, and electron microscopy.
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 384 (1979), S. 93-102 
    ISSN: 1432-2307
    Schlagwort(e): Primary aldosteronism ; Adrenal adenomata ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Adenomata taken from 25 patients with primary aldosteronism were observed by electron microscopy. The cells in the adenoma had a well developed agranular endoplasmic reticulum but granular endoplasmic reticulum was not prominent. Most of the mitochondria resembled those in the cells of the zona glomerulosa, suggesting that the adenomata which caused primary aldosteronism are derived from this zone. Spironolactone bodies were found in the cells of the adenoma from a patient who received spironolactone. Their appearance was identical to that descrived in previous reports.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 225 (1979), S. 57-65 
    ISSN: 1434-4726
    Schlagwort(e): NZB/NZW-Maus ; Ultrastruktur ; Submandibulare Speicheldrüse ; Lymphocyten ; Autoimmunes Leiden ; NZB/NZW mouse ; Ultrastructure ; Submandibular gland ; Lymphocytes ; Autoimmune disease
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary An electron microscopic study of the submandibular salivary gland lesion occurring in the NZB/NZW F1 hybrid mice was performed, and the findings were discussed and correlated to the autoimmune salivary gland disease observed in patients with Sjögren's syndrome. Within the submandibular salivary gland of this mouse strain focal infiltrates of mononuclear inflammatory cells were observed. Lymphoid cells were observed inside the basal lamina of acini and ducts, leading to destruction of these glandular units. The typical duct cell proliferation found in the autoimmune sialoadenitis of Sjögren's syndrome with the formation of the typical epimyoepithelial islands was not found in the submandibular glands of NZB/NZW mice.
    Notizen: Zusammenfassung Eine elektronenmikroskopische Untersuchung der bei den NZB/NZW F1 hybriden Mäusen vorkommenden Veränderungen in den submandibularen Speicheldrüsen wurde durchgeführt, und die Befunde wurden diskutiert und korreliert mit dem autoimmunen Speicheldrüsenleiden, das bei Patienten mit Sjögrens-Syndrom beobachtet wird. In der submandibularen Speicheldrüse dieses Mäusestammes wurden begrenzte Infiltrationen mononuklearer inflammatorischer Zellen beobachtet. Die mononuklearen Zellen wurden hauptsächlich als lymphoide Zellen identifiziert. Außerdem wurden innerhalb der Lamina basilaris von Drüsen und Drüsengängen lymphoide Zellen beobachtet, die zur Zerstörung dieser Drüseneinheiten führen. Darüber hinaus wurde der typische Zuwachs der Drüsengangszellen, der bei der autoimmunen Speicheldrüsenentzündung des Sjögrens-Syndroms vorkommt und die Form von typischen epimyoepithelialen Inseln annimmt, in den submandibularen Drüsen der NZB/NZW-Mäuse nicht vorgefunden.
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 224 (1979), S. 31-35 
    ISSN: 1434-4726
    Schlagwort(e): Intracellular potentials ; Ultrastructure ; Hair cells ; Labyrinth receptors ; Reptilia (Crocodilia, Gekkonidae)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Different biopotentials, following a mechanical stimulus, were recorded from single hair cells of the reptilian labyrinth, with electronoptically circumscript localizations: 1. From the apical cell pole, the receptor potential, intracellular or from the ciliary surface, within the physiological range proportional to stimulus amplitude, frequency or phase, without delay, and with no real threshold of mechanosensitivity, as measured by ciliary displacement amplitude or velocity. 2. From the synaptic zone, in the basal region of the hair cell, or from contacting nerve endings, the synaptic potentials, local excitatory or inhibitory processes, respectively, with measurable latencies and with non-linear distortion. 3. From the (dendritic) endings of the first afferent neuron (or neurons), spike-shaped action potentials, synchronized by the (excitatory) synaptic potentials. Characteristic curves were plotted as a quantitative representation of the mechano-electric input-output relations of the different types of hair cells. For proceeding morphological and physiological system analysis, the comparison of the different submammalian inner-ear receptor systems gives us some new possibilities of a closer correlation between ultrastructure and function.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 28 (1979), S. 43-56 
    ISSN: 1432-0827
    Schlagwort(e): Bone resorption ; Osteogenesis ; Fish bone ; Osteocytes ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The comparative ultrastructure of fish bone osteogenesis and resorption induced by scale removal was described in the osteocytic (cellular-boned)Carassius auratus and the anosteocytic (acellular-boned)Tilapia macrocephala. Osteocytes, present in osteocytic bone, were lacking in anosteocytic bone. In osteocytic bone the osteoblast secreted a collagenous preosseous matrix in which it became enmeshed and then was termed a preosteocyte. When the preosseous matrix mineralized, the preosteocyte was termed an osteocyte and was completely surrounded by bone. In anosteocytic bone the osteoblasts receded from the mineralizing front and never became trapped as osteocytes. During resorption, types A and B resorptive cells, present in both bone types, invaded the matrix and demineralized the osseous zone. These cells were characterized by large amounts of granular endoplasmic reticulum and intracellular inclusions containing crystal-like material. Although functionally similar to mammalian osteoclasts, these cells lacked a characteristic ruffled border and were not multinucleated. The osteocytes of cellular bone did not appear to be involved during demineralization.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 35 (1979), S. 249-267 
    ISSN: 1432-1106
    Schlagwort(e): Abducens nucleus (cat) ; Peroxidase ; Neurones ; Synapses ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Light and electron microscope studies of the abducens nucleus in the cat have disclosed two populations of neurones: large neurones 25 to 75 μm in diameter and small neurones 10 to 25 μm in diameter. Characteristic of the large neurones are a highly developed granular endoplasmic reticulum and a large number of axo-somatic synapses. The small neurones have a poorly developed granular endoplasmic reticulum and comparative by few axo-somatic synapses. Injection of horseradish peroxidase (HRP) into the ipsilateral lateral rectus muscle has been used to identify abducens motoneurones which represent 65% of the total number of cells in the abducens nucleus and form part of the large cell population. The remaining unlabelled large neurones (30% of the large cell population) probably represent motoneurones of the retractor bulbi muscles, abducens motoneurones which have failed to transport the HRP, and possibly internuclear neurones. The small neurones (5% of the total cell population) were never labelled by HRP. Axo-somatic and axo-dendritic synapses are numerous. Many of the synaptic terminals form contacts with two or more different postsynaptic elements. Axo-axonic synapses and synapses on the initial segments of large neurones are also present. Nodal synapses and branching of myelinated axons are common findings. Finally, extended areas of close apposition between dendritic membranes are frequently observed.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Experimental brain research 36 (1979), S. 107-118 
    ISSN: 1432-1106
    Schlagwort(e): Rat ; Hypoglossal nucleus ; Ultrastructure ; Second axotomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The left hypoglossal nerve of adult male albino rats was prevented from regenerating to the tongue after a distal axotomy by implanting the proximal stump into normally innervated left sternomastoid muscle. Eighty-four days after implantation, the hypoglossal nerve was transected again and its regeneration to the tongue unimpeded. From 8 to 70 days after this second axotomy the left hypoglossal nuclei were processed for quantitative ultrastructural analysis. The first aim of this study was to compare regeneration success in the hypoglossal nucleus after second axotomy with that accompanying outgrowth of the hypoglossal nerve into denervated sternomastoid muscle. During quantitative analysis a second aim developed, of elucidating bouton/glial relationships. The second axotomy induced loss and return of subsurface cisterns, dispersal and reassembly of Nissl substance, increase and decrease of microglial numbers, slight further loss and partial return of boutons with clear spherical vesicles and symmetrical synapses, slight increase and decrease of boutons with clear flat vesicles and symmetrical synapses, regrowth of retracted dendrites and restoration of their synapses, and gradual diminution of numbers of electron-dense neurones and dendrites. Astrocytes remained hypertrophied throughout. When compared with events in the hypoglossal nucleus accompanying innervation of denervated sternomastoid muscle by the hypoglossal nerve, the results suggest (1) that regeneration of the hypoglossal nerve to its own tongue muscle instead of to a foreign muscle caused no acceleration of recovery in the hypoglossal nucleus, and (2) that the microglial response is dependent on nerve integrity and not on bouton behaviour.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 384 (1979), S. 307-324 
    ISSN: 1432-2307
    Schlagwort(e): Calcifying odontogenic cyst ; Dysplastic dentin ; Hornified cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Four new cases of calcifying odontogenic cyst (COC) were studied by light- and electronmicroscope. The ages of the patients were between 20 and 68 years. Three cysts were located in the maxilla, the other was in the mandible. The history of two patients was followed up for five and ten years respectively. The longer the history the bigger were the cysts. All cysts showed histologically identical alterations of the epithelium with 1) a pronounced cylindrical basal cell layer, 2) cells resembling stellate reticulum, and 3) ghost cells. So called dysplastic dentin was laid down in the connective tissue only in the two cases with a long history. Ultrastructurally the odontogenic epithelium of all cysts showed keratinization similar to the epidermis. Two types of keratinization are known to occur in the epidermis, soft keratinization with keratohyalin granules in ortho- and parakeratosis, and hard keratinization without keratohyalin granules in nails (horn). Both types of keratinization occur in odontogenic epithelium. The COC is an example of hard keratinization. Ghost cells form prekeratin which in turn becomes horn and is found in areas of confluent ghost cells and in the so called dysplastic dentin. We conclude that the alteration of odontogenic epithelium in COC and in special odontogenic tumors is a secondary phenomenon resembling ortho- and parakeratosis.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 384 (1979), S. 347-355 
    ISSN: 1432-2307
    Schlagwort(e): Exfoliation syndrome ; Non-glaucomatous eye ; Trabecular meshwork ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The trabecular meshwork of a non-glaucomatous eye with the exfoliation syndrome was investigated. The exfoliation material was found mainly in massive deposits in the subendothelial region of the outer and inner wall of Schlemm's canal, in the cribriform area and the uveal meshwork. The other alterations of the trabeculum corneosclerale corresponded to the age of the patient. The concept that the accumulation of exfoliation material is an important pathogenetic factor in the development of glaucoma was not confirmed by this study.
    Materialart: Digitale Medien
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  • 61
    ISSN: 1432-2307
    Schlagwort(e): Hexachlorobenzene ; Liver ; Ultrastructure ; Porphyrins ; Smooth endoplasmic reticulum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Groups of female rats were treated orally with 0.5, 2.0, 8.0, and 32 mg/kg hexachlorobenzene twice a week for 203 days. The liver content of hexachlorobenzene was found to be dose-dependent. In the animals treated with the highest dose the concentration was 273 μg/g hexachlorobenzene. In the fresh and fixed hepatic tissue of the treated animals pink fluorescence was observed. Electron microscopy revealed a dose dependent enlargement of all hepatocytes due to proliferation of the SER in the centrolobular area or to increased glycogen deposits (β- or α-particles) and SER in the intermediary and periportal area. Numerous porphyrin deposits and siderosomes, intimate disorganisation and moderate dislocation of the RER and a moderate enlargement of bizarre-shaped mitochondria were recognized. The relationship between porphyrin crystals and mitochondria on the one hand and between SER and glycogen deposits on the other is discussed.
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 382 (1979), S. 191-200 
    ISSN: 1432-2307
    Schlagwort(e): Rheumatoid arthritis ; Muscle spindles ; Neuromuscular spindles ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural features of muscle spindles were studied in biopsy material from 100 patients suffering from classical rheumatoid arthritis. Thickening of the outer capsule, increased amount of extracellular ground substance within the inner capsule, and marked thickening of the basement membrane of capillary blood vessels supplying the muscle spindles were observed. Chronic inflammatory cells and macrophages were present within the spindles. Changes affecting the intrafusal muscle fibres were also seen. They were manifest as atrophy and degeneration of the intrafusal muscle fibres, absence of the specialised junctional complexes, and of the intercellular bridges, microladders and satellite cells. It is suggested that the changes affecting the intrafusal muscle fibres are probably secondary. Damage to the myelinated nerves was present, while the sensory and motor nerve endings were well preserved.
    Materialart: Digitale Medien
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 382 (1979), S. 201-216 
    ISSN: 1432-2307
    Schlagwort(e): Meningioma ; Ultrastructure ; Classification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We examined 23 meningiomas by electron microscopy. In each case it was possible to distinguish certain cells with epithelial features (desmosomes, microfilaments, interdigitating extensions) and others with fibroblastic features (collagen fibers). Others cells of transitional form were also seen. The proportion of these cellular types is variable, making it possible to classify meningiomas into seven types progressing gradually from a purely epithelial type to a purely fibroblastic one. We found no important ultrastructural abnormalities in the cells. These case reports confirm the uniqueness of meningiomas, which are composed of variously shaped cells but have their origin from a single cellular type. This has double potentiality for fibroblastic and epithelial differentiation.
    Materialart: Digitale Medien
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 382 (1979), S. 237-243 
    ISSN: 1432-2307
    Schlagwort(e): Giant cell tumors of tendon sheath ; Soft tissue tumors ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A benign, but aggressive, giant cell tumor of tendon sheath developed over a period of 20 years into a metastasizing, histologically malignant giant cell tumor. Ultrastructure of the malignant tumor showed the same five cell types as described in giant cell tumors of tendon sheath. Even the same crystals were identified in the osteoblast-like and osteoclast-like cells. It therefore appears reasonable to assume that giant cell tumors of tendon sheath indeed are neoplasms with a malignant potential and not an inflammatory reaction of synovial cells as previously suggested. Both the benign and malignant tumors seem to be of mesenchymal derivation with partial osseous differentiation. No ultrastructural similarities with fibrous histiocytoma were apparent.
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 383 (1979), S. 181-193 
    ISSN: 1432-2307
    Schlagwort(e): Graves' disease ; Preoperative treatment ; Ultrastructure ; Antithyroid drug treatment ; Lithium ; Cellular involution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This electron microscopic study is based on 12 cases of toxic goiter treated preoperatively with iodide, thionamides and lithium. Essential features of Graves' disease include hypertrophy of the follicular epithelium, papillary follicular infoldings and frequently, lymphocytic infiltration and fibrosis. After preoperative therapy most thyroid glands show involutional changes of varying degree with reaccumulation of colloid and flattening of the follicular epithelium. In a small number of histologically examined cases (n=84) colloid goitre (13%) and nodular goitre (8%) were noted. Lymphocytic infiltration and interstitial fibrosis do not show any correlation with preoperative treatment. Ultrastructurally, different stages of cellular involution are seen. The hypertrophic follicular cell shows an increased cell surface with numerous long microvilli and some pseudopodia at the apical border and an occasionally thickened, basal lamina. The cytoplasm contains a well developed system of organelles which synthesizes (rough endoplasmic reticulum, Golgi apparatus, cytoplasmic vesicles) and degrades (colloid droplets, lysosomes) thyroglobulin. With increasing cellular atrophy we found cells to be reduced in size but to contain well developed thyroglobulin-synthesizing organelles. Finally, we observed completely atrophic flat cells with only a few organelles. There are at date no electron microscopic communications on lithiumpretreated thyroid glands. After lithium therapy characteristic changes are observed at the membranes of the cytocavitary system, which are often found to be thin and occasionally to be damaged. The rough endoplasmic reticulum is virtually deprived of ribosomes and the Golgi apparatus seems to be underdeveloped. The number of apical microvilli is reduced. The morphological findings following iodide-, thionamide- and lithium pretreatment in Graves' disease are discussed in light of recent biochemical results.
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 381 (1979), S. 189-203 
    ISSN: 1432-2307
    Schlagwort(e): Pseudomalignant ossifying myositis ; Ultrastructure ; Myofibroblasts ; Macrophages ; Pathogenesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Seven cases of pseudomalignant ossifying myositis with a typical clinical symptomatology have been reported. None of the cases had experienced an injury. All the lesions were intramuscular and all of them showed a zonal arrangement. Electron microscopy in three cases allowed the demonstration of cells showing morphological features of myofibroblasts and monocytic cells of the macrophage type. These previously unreported features together with the zonal pattern of the lesions indicate their reparative nature.
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 381 (1979), S. 121-139 
    ISSN: 1432-2307
    Schlagwort(e): Myxofibrosarcoma ; Fibroblast ; Histiocyte ; Myofibroblast ; Sarcoma ; Soft tissue tumour ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An ultrastructural study of 11 myxofibrosarcomas is presented. The tumours were graded light-microscopically on a four-point scale according to cellularity, cell atypia and mitotic activity, as described in a previous paper: 3 were grade I, 2 grade II, 4 grade III and 2 grade IV. Fibroblast-like and myofibroblast-like cells predominated in the grade I and II tumours, while histiocyte-like cells were relatively few; in grade III and IV tumours histiocyte-like cells predominated. The fibroblast-like cells were spindle-shaped with fairly smoothly outlined nuclei, and contained abundant parallel membranes and wide cisternae of endoplasmic reticulum. The histocyte-like cells were irregular in shape and showed indented nuclei with large nucleoli and coarse, peripherally arranged clumps of heterochromatin. The cytoplasm of these cells showed prominent pseudopodiae, microvillous projections, conspicuous systems of vesicles and vacuoles, inclusions of lipid and pigment, numerous lysosomal structures and large digestive vacuoles indicating auto- and exophagocytosis. The myofibroblast-like cells showed abundance of parallelly arranged cytoplasmic microfilaments with dense body-like structures and condensation at the plasmic membrane. Occasional cells appeared to be intermediate forms and primitive looking, undifferentiated cells were also encountered. A few multinucleated tumours cells were seen in the grade IV tumours. Thus, the present study shows the composite fibroblastic, myofibroblastic and histiocytic character of the tumour cells of myxofibrosarcoma; the grade III and IV tumours, with a tendency to contain solid areas, seem to be closely related to the pleomorphic type of malignant fibrous histiocytoma.
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 382 (1979), S. 217-226 
    ISSN: 1432-2307
    Schlagwort(e): Axonal swelling ; Spheroid ; Dystrophic axon ; Ultrastructure ; Human gracile nucleus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The morphology of the spheroids in human gracile nuclei was studied by light and electron microscopy. Various spheroids encountered in the present study could be classified into three types based on the internal structure: The first one was chiefly composed of many irregular homogeneous dense bodies, multivesicular bodies and mitochondria. The dense bodies seemed to deposit multicentrically in an axon in the early stage of “balloon” formation and coalesce to form larger ones. The second was characterized by a marked accumulation of closely approximated mitochondria and dense concentric bodies. In the third the most characteristic findings were neurofibrillary accumulation and aggregations of dense bodies. These findings showed some divergence from those of dystrophic axons and the last two mimic those of degenerative or regenerative axons, which suggested that axonal swelling (including dystrophic axon) is not characteristic reaction of specific disease but rather nonspecific one to a variety of noxious stimuli. With light microscope, it was difficult to distinguish balloons with different structures since they were quite diverse and manifold in their shape, size, appearance and stainability. Intra-axonal corpora amylacea were seen in most cases and their incidence appeared to be nonspecific for any diseases.
    Materialart: Digitale Medien
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 385 (1979), S. 93-101 
    ISSN: 1432-2307
    Schlagwort(e): Angioma ; Lung ; Carcinoma ; Pneumocytes ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Elektronenmikroskopische Untersuchung eines sog. sklerosierenden Hämangioms der Lunge, das im Oberlappen einer 32jährigen Frau zufällig entdeckt wurde. Der seltene gutartige Tumor, der lichtmikroskopisch wegen seines Gefäßreichtums an ein Hämangiom erinnert, zeigt elektronenmikroskopisch eine eindeutige epitheliale Struktur. Die Geschwulst entwickelt sich möglicherweise aus unreifen Pneumocyten. Histogenese sowie differential-diagnostische Probleme (Verwechslungsmöglichkeit mit Carcinom) werden diskutiert.
    Notizen: Summary Electron microscopy of a sclerosing angioma of the lung, a coincidental finding in the upper lobe of a 32-year-old woman. The rare, benign tumor, whose vascular proliferation by light microscopy is reminiscent of an angioma, exhibits a clear epithelial structure by electron microscopy. The tumor may develop out of immature pneumocytes. The paper discusses histogenesis and problems of differential diagnosis (potential confusion with carcinomas).
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Research in experimental medicine 176 (1979), S. 69-79 
    ISSN: 1433-8580
    Schlagwort(e): Skeletal muscle ; CO2-laser ; Surgery ; Ultrastructure ; Rat ; Skelettmuskelfaser ; CO2-Laser ; Chirurgie ; Ultrastruktur ; Ratte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Der Zustand der dorsalen Haut und des darunterliegenden Muskelgewebes der Ratte wurde unmittelbar nach CO2-Laser-Schnitten mit Hilfe von licht- und elektronenmikroskopischen Methoden untersucht. In der subkutanen Skelettmuskelschicht konnte eine erhöhte Empfindlichkeit des Gewebes festgestellt werden, die in einer ausgeprägten Abfolge von Zellveränderungen ihren Ausdruck findet. Diese Schädigungen werden hauptsächlich den thermischen Effekten der Laserstrahlung zugeschrieben. Die Bedeutung dieser Untersuchungsergebnisse in Hinblick auf die Verwendung von Laser in der Chirurgie wird besprochen.
    Notizen: Summary The immediate effect of CO2-laser incision to the dorsal skin and underlying muscular tissue of rats was studied by light and electron microscopical methods. In the subcutaneous layer of skeletal muscle cells an increased susceptibility was found, resulting in distinct zones of cellular changes which are attributed mainly to thermal effects of the laser beam. The importance of these findings for the surgical application of lasers is discussed.
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 155 (1979), S. 95-105 
    ISSN: 1432-0568
    Schlagwort(e): Metanephros ; Chicken embryo ; Ultrastructure ; Parathyroid hormone ; Cyclic AMP
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A comparative electron microscopical study was conducted on the metanephros from chick embryos differentiated either in shell-less culture or in ovo. Developmental characteristics were very similar in both cases. Up to stage 37 (Hamburger-Hamilton) the metanephros contained large numbers of immature nephrons; their renal corpuscles were crescent-shaped and consisted of an outer layer of flat cells and an inner one of cuboidal cells. In more advanced corpuscles also found at this stage the inner layer had formed numerous rudimentary pedicels and the tunica media of the glomerular arteriole contained juxta-glomerular cells with numerous, small, electron dense granules. In the metanephros from embryos at stage 38 or older, large numbers of nephrons had completed their differentiation; their rounded renal corpuscles had fully differentiated podocytes with thin interdigitating pedicels and the proximal convoluted tubules had numerous apical microvilli, vesicles, vacuoles and tubular invaginations indicating an active process of resorption. These results appear to indicate that both in culture and in ovo-developed embryos, the metanephri start to function around stage 38. In the case of normal embryos this conclusion agrees with previous physiological and biochemical determinations. The injection of 20 USP parathyroid hormone into 16-day old chick embryos produced an increase in the concentration of cyclic AMP in the metanephros. This favours the idea that the regulation of kidney function by the hormone begins during the embryonic period.
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 155 (1979), S. 333-345 
    ISSN: 1432-0568
    Schlagwort(e): Lipofuscin ; Cerebellar cortex ; Ultrastructure ; Senescent rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of autofluorescent, PAS-positive lipofuscin in Purkinje, granule, Golgi epithelial, basket and stellate, microglial and perivascular cells in the cerebellar cortex of senescent rats is described. The membrane-bounded pigment is composed of three elements: 1) electron-lucent homogeneous droplets, 2) a granular matrix and 3) intensely osmiophilic patches. The proportions of these three components vary between cell types and one can grossly differentiate a neuronal and a glial lipofuscin. The lipofuscin granules of stellate and perivscular cells are different from lipofuscin of other cerebellar neurons and glia. It can be concluded from these morphological observations that each cerebellar cell type has its distinct lipofuscin.
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 46 (1979), S. 215-220 
    ISSN: 1432-0533
    Schlagwort(e): Melanosis of the dentate nucleus ; Glial melanin ; Ultrastructure ; Intrared spectroscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The pigment present in melanosis cerebelli where it is deposited in the dentate nucleus and within the cerebellar granular layer is similar to that of S. nigra as judged from the typical infrared absorption bands near wave numbers 3.450 cm−1 and 1.650 cm−1, respectively. According to electron microscopic findings, this type of melanin arises within the astrocytes of the dentate nucleus. The astrocytic melanosomes exhibit a relatively monotonous substructure reaching diameters of 30 μ and more, and they differ in this respect from the triadic neuronal melanosomes of S. nigra that are strongly reminiscent of lipofuscin granules. These differences may be due to additional components of melanosomes, apparently specific of a particular cell type, and they are in turn accounted for by the dissimilar cellular metabolic make-up of nigral cells and astrocytes, respectively. This does not dismiss the possibility, however, that the melanin pigments of either type of melanosomes are the same or closely related to each other as far as their basic chemical composition is concerned. The cause of the melanosis of the dentate nucleus is not known. Possibly involutional tissue changes governed by endocrine factors among others may play an important part.
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 47 (1979), S. 85-92 
    ISSN: 1432-0533
    Schlagwort(e): Isoniazid ; Neuropathy ; Intoxication ; Dying back ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Large single doses of isoniazid by mouth (1–2 g/kg) have been shown to produce in rats Wallerian degeneration visible with the light microscope from the third day onwards. By contrast, changes in axons are seen from 24 h onwards by electron microscopy. The earliest ultrastructural changes are associated with vacuoles appearing between axon and Schwann cells. These are large and focal, and often compress the axon. The adjacent axon may show changes in smooth ER, and in microtubular arrangement. Alterations in smooth membranes and in mitochondria are visible in Schwann cell cytoplasm, not necessarily related to the vacuole formation and axonal features. It is suggested that INH neuropathy is essentially a multifocal axonal lesion.
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 47 (1979), S. 139-143 
    ISSN: 1432-0533
    Schlagwort(e): Perineurium ; Permeability ; Peripheral nerve ; Rat ; Ultrastructure ; Autoradiography ; Albumin ; Peroxidase ; Protein deprivation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The permeability properties of the perineurium in sciatic nerves of 12-week-old rats were studied. The penetration of125I-labeled albumin and horseradish peroxidase into the perineurium was investigated electronmicroscopically 10, 30, and 120 min after the local extraneural application of the tracers. The autoradiographic study included age-matched protein-deprived rats. It was concluded that the perineurium acted as a diffusion barrier but also permitted a slow passage of the macromolecules into the endoneurium. The result indicates that this penetration to some extent is due to vesicular transport across the perineurial cells. The significance of these barrier and transport properties of the perineurium is discussed. No obvious differences in perineurial permeability between normal and protein-deprived rats were obtained.
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 48 (1979), S. 67-72 
    ISSN: 1432-0533
    Schlagwort(e): Pituitary adenoma ; Ultrastructure ; Classitication
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of pituitary adenoma secreting more than two hormones is presented. Morphological findings of this tumor have been correlated with biological behavior and with hormonal activity.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 48 (1979), S. 189-197 
    ISSN: 1432-0533
    Schlagwort(e): Hamster brain cells ; Polyoma virus ; Tumorigenicity ; Ultrastructure ; Specific nervous proteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The morphological characteristics of three clones of hamster brain cells transformed in vitro by polyoma virus and of the tumors obtained after subcutaneous grafting of these cells in syngenic animals are reported. These clones appeared to be glial in nature by light and electron microscopy. The initial tumors induced by the three clones presented astrocytic features both by electron microscopy and immunohistochemistry. Analysis of the subsequent in vivo passages showed a decrease in cell differentiation, which was accompanied by a decrease in the latency period; after 2 years of serial transplantation, the tumors seemed poorly differentiated gliomas. A control cell line of hamster cerebellar cells evolved similarly.
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 48 (1979), S. 27-30 
    ISSN: 1432-0533
    Schlagwort(e): Progressive supranuclear palsy ; Neurofibrillary tangles ; Ultrastructure ; Straight tubule ; Twisted tubule
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The fine structure of neurofibrillary tangles in the hippocampal gyrus, substantia nigra, pontine nuclei and locus coeruleus of the brain was postmortem studied in a case of progressive supranuclear palsy. Straight tubules and twisted tubules were observed in both the cortical and subcortical neurofibrillary tangles. Most tubules appeared separately in each neuron but a few straight tubules were mixed with the twisted tubules in the cortical tangles. The implication and possible significance of this findings are discussed.
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  • 79
    ISSN: 1432-0533
    Schlagwort(e): Melanin ; Melanosomes ; Ultrastructure ; Infrared spectrophotometry ; X-ray diffraction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Melanosomes and isolated melanosomal fragments (melanin particles) originating from gangliocytes (substantia nigra), astroglia (melanosis cerebelli), and melanocytes (melanotic meningeoma; metastases of melanoblastoma; melanosis thalami of the goat) were compared with synthetic melanins prepared from dopamine and serotonin, respectively. Samples were examined by electron microscopy, X-ray diffraction analysis according to Debye-Scherrer and by infrared spectrophotometry, and the results were evaluated with regard to characteristic features as they may relate to specific cell types or chemical structures. On electron microscopy all three types of melanosomes could be differentiated unequivocally as could the two synthetic melanins. Thus, there were similarities between synthetic melanin from dopamine and the gliogenic melanins of the cerebellum; the synthetic melanin from serotonin resembled melanin of melanocytes. X-ray diffraction analysis yielded 2-4 Debye diffraction rings with all human and synthetic samples, suggesting short range orders between 3.8 to 5 Å the sample obtained from a goat with thalamic melanosis showed a specific reflex pattern. While diffraction patterns of some melanins were partially identical, in particular that of melanin from dopamine and melanin of substantia nigra and dentate nucleus, respectively, they were different for the various melanocytic melanins. Further investigations are required to determine whether these differences are due to disparities in basic chemical structures or conformations or else, to particular compositional features of the various types of melanocytes as they arise from benign or malignant tumors or a specific species. Infrared spectrophotometry at higher wave numbers revealed the well known patterns of melanins, which are not, however, very suitable, for their further differentiation. At lower wave numbers (‘fingerprinting’) melanin of substantia nigra and the glial melanin in melanosis cerebelli yielded additional absorption bands of identical configuration. In contrast to melanin from dopamine, melanin from serotonin exhibited a closely similar absorption pattern in this spectral range, suggesting that the neuroectodermal melanins may contain a component possibly arising from serotonin.
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 156 (1979), S. 73-88 
    ISSN: 1432-0568
    Schlagwort(e): Closure ; Development ; Mammalina embryo ; Neural tube ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The fusion of the neural walls in the cephalic part of mouse embryos varying in age from 9 to 20 somites was examined with the electron microscope. In the rhombencephalic region the rim of the neural wall was formed from outside inward by ectodermal surface cells, a row of flattened cells without surface projections and neuroepithelial cells. At the junction of the surface ectoderm and the flat cells were seen large projections containing a cytoplasmic matrix without organelles and previously referred to as “ruffles”. The initial contact between the walls was made by the large cytoplasmic arms and numerous finger-like projections interdigitating with similar projections from the opposite wall. The projections originated from the surface ectoderm and possibly neural crest cells. During further fusion the surface ectoderm cells formed dense membrane specializations, thus establishing a firm contact. The initial contact in the mesencephalon was formed by extensions from the surface ectoderm and was followed by the formation of specialized membrane junctions, as seen between the surface ectoderm in the rhombencephalon. The neuroepithelial cells facing the gap between the neural walls with their apical ends made contact with the cells from the opposing wall by numerous finger-like projections but membrane specializations failed to develop. The closing mechanism in the prosencephalon and anterior neuropore regions differed from the previous areas in that the initial contact was established by the neuroepithelial cells. Only after this contact had been formed did the surface ectoderm cells close the gap. In contrast with the other areas many phagocytosed particles were seen in the prosencephalon and in the region of the anterior neuropore. Many particles from degenerated cells were found inside healthy surrounding cells. Some of these particles contained nuclear material and cytoplasmic organelles.
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 156 (1979), S. 255-267 
    ISSN: 1432-0568
    Schlagwort(e): Adenohypophyseal rudiment ; Self-differentiation ; Ultrastructure ; Quail
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Isolated epithelial rudiments of 3–4 days quail embryo adenohypophysis were cultivated in vitro. Differentiation of glandular cells occured when culture conditions allowed the formation of explants characterized by the presence of a fibroblastic sheet and of an epithelial roof surrounding a central cavity. Differentiation did not occur when culture conditions did not allow the fibroblastic sheet to be established or resulted in the absence of a cavity. The importance of the explant structure in differentiation is also indicated by the location of glandular cells. In vitro they differentiate near the cavity derived from Rathke's pouch lumen while in situ they first appear at the periphery of the rudiment, near the basement membrane. The results of this study show that the adenohypophyseal primordium can differentiate without any mesenchymal influence. The observed differentiation seems to be correlated with fibroblast-secreted material, and this hypo-thesis is discussed.
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 266 (1979), S. 143-159 
    ISSN: 1432-069X
    Schlagwort(e): Xanthoma ; Ultrastructure ; Lipid vacuoles ; Myelin figures ; Xanthoma ; Ultrastruktur ; Lipidvacuolen ; Myelinfiguren
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Eine elektronenmikroskopische Untersuchung von 10 Patienten mit normolipämischer Xanthomatose und von 2 Patienten mit hyperlipoproteinämischer Xanthomatose Typ IV und V ergab folgende Befunde: In allen Fällen wurden große Mengen von Histiocyten mit intracytoplasmatischen Lipid-Vacuolen, Lysosomen und Myelinfiguren gesehen. Dazu waren Mikrofilamente und Lipid-Vacuolen in einigen Fibroblasten zu beobachten. In sämtlichen Präparaten fanden sich mehrkernige histiocytäre Riesenzellen mit kristallinen Spalträumen sowie einige Mastzellen. Lipid-Vacuolen konnten auch in Schwannzellen, Endothelzellen und in Pericyten nachgewiesen werden. In einigen Endothelzellen und Pericyten beobachtete man Duplikaturen der basalen vaskulären Laminae und “rob-shaped” tubuläre Körperchen. Beim Xanthelasma palpebrarum und dem Xanthoma planum disseminatum fanden sich die histiocytären Schaumzellen in perivaskulärer Anordnung, wie bei den hyperlipoproteinämischen Xanthomatosen. Wir folgern, daß die ultrastrukturellen Aspekte in den verschiedenen Xanthomatosen im wesentlichen gleich sind, zumal große Ablagerungen von Fett in allen Zellen zu sehen sind. In den normolipämischen Xanthomatosen (Xanthelasma palpebrarum und Xanthoma planum disseminatum) ist die Art der Entstehung von Fettablagerungen vermutlich die gleiche wie bei den hyperlipoproteinämischen Xanthomatosen; sie unterscheiden sich jedoch von den Fettablagerungen beim Xanthoma disseminatum und beim Xanthogranuloma juvenile. Eine Einteilung der normolipämischen Xanthomatosen wird vorgestellt.
    Notizen: Summary Electron microscopic aspects in ten cases of normolipidemic cutaneous xanthomatosis have been investigated. Two additional types IV and V hyperlipoproteinaemic xanthomatosis have also been included. Ultrastructural findings in all cases were similar. Abundant histiocytic cells with numerous intracytoplasmic lipid vacuoles, lysosomes, and myelin-figures, were the striking features. Moreover, in older lesions microfilaments and lipid vacuoles were found in some fibroblastic cells, as well as long space collagen around them. In some specimens we observed: giant multinucleated histiocytic cells, crystalline cleft-like spaces in histiocytes and some mastocytes with lipidic crystals in the extracellular space, as well as lipid vacuoles in Schwann cells, endothelial cells and pericytes. Rod-shaped tubulated bodies were found in some endothelial cells, with multiple basal vascular laminae. In xantelasma palpebrarum and in disseminate plane xanthoma the histiocytary foamy cells adopted a perivascular arrangement, as in hyperlipoproteinemic xanthomatosis. We concluded that ultrastructural aspects of different xanthomatosis are fairly similar as a consequence of the large amount of intracytoplasmic lipids accumulated in xanthomatous cells. In xanthelasma palpebrarum and in disseminated plane xanthoma this cell phase is reached by similar pathways to those for hyperlipoproteinemic xanthomatosis, whilst in xanthoma disseminatum and juvenile xanthogranuloma the pathways seem to be different. A classification of normolipidemic xanthomatosis is also provided.
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 266 (1979), S. 187-196 
    ISSN: 1432-069X
    Schlagwort(e): Disseminated lipogranulomatosis ; Farber's disease ; Sphingolipidoses ; Ceramide ; Ultrastructure ; Disseminierte Lipogranulomatose ; M. Farber ; Sphingolipidosen ; Ceramid ; Ultrastruktur
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Eine elektronenmikroskopische Untersuchung von 2 Hautläsionen bei einem aus der Türkei stammenden 2jährigen Jungen mit disseminierter Lipogranulomatosis (Farber) zeigte curvilineare Körper in Fibroblasten, Histiocyten und Endothelzellen, flache Membrananordnungen in Fibroblasten und Endothelzellen und spindelartige Körper in Schwann-Zellen. In peripheren Lymphocyten fanden sich nur Veränderungen der Mitochondrien (Schwellung und aufgebrochene Cristae), jedoch keine Einschlußkörper. Die intracytoplasmatischen curvilinearen Körper waren zahlreich und leicht nachweisbar. Sie scheinen für den M. Farber spezifisch zu sein, und es wird vorgeschlagen, sie “Farber Körper” zu nennen. Die Diagnose dieser Ceramidspeicherkrankheit, in der das histologische Bild weitgehend unspezifisch ist, kann daher ultrastrukturell bestätigt werden.
    Notizen: Summary An ultrastructural investigation of two cutaneous lesions in a two-year-old Turkish boy with disseminated lipogranulomatosis (Farber) revealed curvilinear bodies in fibroblasts, histiocytes, and endothelial cells; “elongated membranes” in fibroblasts and endothelial cells; “zebra bodies” in endothelial cells; and spindle-shaped bodies in Schwann cells. In peripheral lymphocytes only alterations of mitochondria (swelling and ruptured cristae) but no inclusion bodies were found. Curvilinear bodies were numerous and easily identifiable; they appear to be characteristic of Farber's disease, and naming them “Farber bodies” is proposed. The diagnosis of this ceramide storage disease, in which the histological examination is relatively unspecific, can therefore be confirmed ultrastructurally.
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 266 (1979), S. 239-251 
    ISSN: 1432-069X
    Schlagwort(e): Cutaneous malignant B-cell lymphoma ; Ultrastructure ; Semithin sections ; Cutane maligne B-Zell Lymphome ; Ultrastruktur ; Semidünnschnitte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Achtzehn Fälle von cutanen B-Zell Lymphomen von niedrigem Malignitätsgrad (gesichert durch Enzymcytochemie und Immuncytologie) wurden morphologisch mittels Semidünn- und Dünnschnitten unter-sucht. Vier Typen mit einem charakteristischen Muster von verschiedenen lymphoiden Zellen wurden gefunden: (1) Der lymphocytische Typ, überwiegend aus kleinen Lymphocyten bestehend; (2) der lymphocytoide (zentrocytische oder prolymphocytische) Typ, bei dem neben kleinen auch mittelgroße Lymphocyten (mit und ohne geknitterten Zellkernen) erscheinen; (3) der lymphoplasmacytoide Typ, bei dem neben kleinen und mittelgroßen Lymphocyten lymphoide Zellen mit unterschiedlich ausgeprägten Differenzierungsmerkmalen von Plasmazellen zu finden sind; sowie (4) der zentroblastische-zentrocytische Typ. Hier sind neben kleinen und mittelgroßen Lymphocyten auch Zentroblasten zu beobachten. Insgesamt stimmen die hier erhobenen morphologischen Befunde gut mit entsprechenden nodalen malignen Lymphomen überein. Die Anwendung moderner Klassifikationen von non-Hodgkin Lymphomen, insbesondere die »Kiel-Klassifikation«, erscheint daher auch für die Hautlymphome gerechtfertigt. Dünn- und Semidünnschnitte eignen sich bei der Routinediagnostik von derartigen Krankheitsfällen, vor allem dann, wenn mit Paraffinschnitten keine klare diagnostische Einordnung erfolgen konnte.
    Notizen: Summary Eighteen cases of low grade malignant B-cell lymphomas (confirmed through enzyme cytochemistry and immunocytology) were investigated morphologically using thin and semithin sections. Four types with a characteristic pattern of different lymphoid cells were found: (1) the lymphocytic type, predominantly consisting of small lymphocytes; (2) the lymphocytoid (centrocytic or prolymphocytic) type, in which in addition to small lymphocytes medium-sized lymphocytes (with or without cleaved nuclei) are found; (3) the lymphoplasmacytoid type, where lymphoid cells with different degrees of similarity to plasma cells are seen as well as small and medium-sized lymphocytes; and (4) the centroblastic-centrocytic type, in which centroblasts are present next to small and medium-sized lymphocytes. These findings correlate well with the morphological observations in low-grade malignant B-cell lymphomas of the lymph nodes. Therefore, the application of modern classifications of non-Hodgkin lymphomas, such as the “Kiel Classification”, to cutaneous lymphomas appears justified. Thin and semithin sections are particularly useful in suspected cases of cutaneous malignant lymphoma, in which paraffin sections did not allow the diagnosis to be established.
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 48 (1979), S. 211-214 
    ISSN: 1432-0533
    Schlagwort(e): Medullomyoblastoma ; Desmoplastic medulloblastoma ; Teratoid ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of cerebellar medullomyoblastoma in a young boy was investigated by electron microscopy. The neuroectodermal component shows the characteristics of a desmoplastic medulloblastoma. The mesodermal component consists of more or less differentiated cross-striated muscle cells. Undifferentiated muscle cells are very similar to proliferated endothelial cells of blood vessels within the muscular component, so that an origin of this component from pluripotential endothelial cells of the vessel wall is suggested. This tumor is considered a malignant teratoid because of the derivation from two blastodermic layers and because of the midline localization in children suggesting a malformative origin.
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 264 (1979), S. 17-28 
    ISSN: 1432-069X
    Schlagwort(e): Malignant lymphoma ; Mycosis fungoides ; Sezary's syndrome ; Parapsoriasis en plaques ; Ultrastructure ; Semi-thin sections ; Maligne Lymphome ; Mykosis fungoides ; Sézary-Syndrom ; Parapsoriasis en plaques ; Ultrastruktur ; Semi-Dünnschnitt-Technik
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Semi-Dünnschnitte erlauben eine bessere morphologische Differenzierung von lymphoiden Zellen als Paraffinschnitte. Zur Prüfung ihrer möglichen Bedeutung bei der Diagnostik von kutanen T-Zell-Lymphomen wurden folgende Untersuchungen durchgeführt: Lymphoide Zellen im cellulären Infiltrat von Hautläsionen bei Mykosis fungoides (11 Fälle), Sézary-Syndrom (9 Fälle) und Parapsoriasis en plaques (14 Fälle) wurden mittels Semi-Dünnschnitten von Epon-eingebetteten Biopsien quantitativ analysiert. Als Kontrollen wurden Biopsien von Epikutan-Test-Reaktionen, Kontaktdermatitis, initialer Psoriasis und Erythema chronicum migrans untersucht. Eine hohe Prozentzahl von Lutzner-(Sézary)-Zellen fand sich ständig beim Sézary-Syndrom und gelegentlich bei der Parapsoriasis en plaques. Bei der Mycosis fungoides überwogen lymphocytoide Zellen mit helleren Kernen als bei normalen Lymphocyten. In den meisten Tumorläsionen sowohl bei der Mycosis fungoides als auch beim Sézary-Syndrom fand sich eine erhöhte Prozentzahl von Immunoblasten. Lymphocyten waren der häufigste Zelltyp bei der Parapsoriasis en plaques und bei den Kontrollen. Diese Befunde könnten nützlich für die Diagnostik von Problemfällen sein, für die die Semi-Dünnschnitt-Technik als eine weitere Methode empfohlen wird.
    Notizen: Summary Semi-thin sections are superior to paraffin sections for differentiating lymphoid cells. To test their possible significance in the diagnosis of cutaneous T-cell lymphomas, the following investigation was made: A quantitative analysis of lymphoid cells in the cellular infiltrate of cutaneous lesions of mycosis fungoides (11 cases), Sézary's syndrome (9 cases), and parapsoriasis en plaques (14 cases) was made using semi-thin sections of eponembedded biopsies. As controls biopsies of patch test reactions, contact dermatitis, initial psoriasis, and erythema chronicum migrans were studied. A high percentage of Lutzner (Sézary) cells was consistently found in Sézary's syndrome and occasionally in parapsoriasis en plaques only. In mycosis fungoides lymphocytoid cells with the nuclei, less dense than in normal lymphocytes were predominant. In most tumorous lesions of mycosis fungoides and of Sézary's syndrome an increased percentage of immunoblasts was noted. Normal lymphocytes were the most frequent cell type in parapsoriasis en plaques as well as in the controls. These findings may prove helpful in the diagnosis of problem cases, for which the use of semi-thin sections is recommended.
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 45 (1979), S. 17-25 
    ISSN: 1432-0533
    Schlagwort(e): Brindled mutant mouse ; Male hemizygotes ; Neuronal degeneration ; Ultrastructure ; Giant mitochondria ; Copper deficiency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The brindled mouse (Mobr) is a neurological mutant mouse with clinical and biochemical features closely similar to Kinky hair syndrome (KHS) in humans. Neuronal degeneration in the cerebral cortex and thalamic nuclei was the constant neuropathological lesions in the CNS of the male hemizygotes of this mutant (Yajima and Suzuki, 1978). Ultrastructurally, many cortical neurons contained enlarged mitochondria with prominent tubular or vesicular cristae, which were similar to those described in the Purkinje cells in the human KHS (Ghatak et al., 1972) and in the rat brain with copper deficiency (Prohaska and Wells, 1975). Such mitochondria were observed not only in the degenerating neurons but even in the otherwise normal-appearing cortical neurons, suggesting that the mitochondrial damage possibly related to the deficient activities of the copper containing enzymes (cytochrome oxidase, etc.) preceded the neuronal degeneration. Many mitochondria in the severely degenerated neurons contained numerous electron dense spicules of possible calcium. Although rare, similar morphological alteration of neuronal mitochondria was also noted in the female heterozygotes, indicating the presence of possible subclinical defect in copper transport in the heterozygotes as well.
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 45 (1979), S. 111-115 
    ISSN: 1432-0533
    Schlagwort(e): Brain tumor ; Rhabdomyosarcoma ; Mesenchymal cell ; Myotube ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of primary cerebral rhabdomyosarcoma in a 51-year-old female is reported. The histogenesis of this tumor is discussed. The clinicopathological features of 10 previously reported similar tumors of the CNS are briefly reviewed. Histologically the tumor was polymorphic, but composed of poorly differentiated cells interpreted as rhabdomyoblasts without definite cross-striation. Electron microscopy established that the poorly differentiated cells were of rhabdomyosarcomatous nature, compatible with presumptive myoblasts and analogous to developing fetal muscle.
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  • 89
    ISSN: 1432-0533
    Schlagwort(e): Muscular dystrophy ; Becker-type ; Benign X-linked ; Histopathology ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Muscle biopsies of two patients originally reported in the Göttingen family by Becker (1962) that formed the basis of separating a benign X-linked muscular dystrophy from the rapidly progressive Duchenne-type X-linked muscular dystrophy, revealed mild pathological changes in the younger patient and more advanced in the older one, consisting of increased spectra of fiber diameters, endomysial fibrosis, angulated fibers, pyknotic nuclear clumps and small groups of atrophic fibers. Essentially, both biopsies showed the same changes, but of different severity, possibly due to the differences in age and muscle biopsy sites. These changes were regarded “myopathic”, but a neurogenic component was suggested. Our observations accord well with those of a larger series (Bradley et al., 1978) where both electromyography and histopathology revealed a mixed “myopathic-neurogenic pattern” in patients with Becker-type dystrophy. Differential diagnostic aspects encompass Duchenne's muscular dystrophy, the other hereditary dystrophies and X-linked proximal spinal muscular atrophies. The precise nature of Becker-type muscular dystrophy requires morphological data on peripheral nerves, spinal roots and spinal cord anterior horn cells as well as sequential biopsy analysis to substantiate the primary site of pathology. However, on the basis of available data, it seems reasonable to suggest that the early changes of degeneration/regeneration which are accompanied by a markedly elevated CPK eventuate in the histopathologic and electromyographic patterns illustrated in these two patients with Beckertype dystrophy.
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 46 (1979), S. 11-15 
    ISSN: 1432-0533
    Schlagwort(e): Meningioma ; Cell culture ; Ultrastructure ; Cell junctions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural alterations in human meningioma cells grown in vitro are reported. In early passages the cells retain some of the characteristic features of the original tumors. These include interdigitations associated with intercellular junctional devices (e.g., desmosomes, gap junctions). However, with repeated subculture these features tend to be less frequent. Typical whorl formations are observed only in primary cultures. The nunber of cytoplasmic filaments, lipid inclusions and other dense bodies increases with time in culture. Cytoplasmic invaginations into nuclei and the appearance of very large cells become more frequent in repeatedly transferred cultures.
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 47 (1979), S. 75-79 
    ISSN: 1432-0533
    Schlagwort(e): Neurotoxicity ; Cyanate ; Demyelination ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of sodium cyanate (NaNCO) on the nervous system of Maccaca nemestrina were studied at 2, 4, and 6 months of administration of the drug. The two groups injected with daily doses of 35 and 25 mg/kg/day of Na-cyanate developed a predominantly demyelinating lesion in the pyramidal tracts of the spinal cord. No neuronal changes were observed in the motor cortex, basal ganglia, midbrain, medulla or anterior horn cells of the spinal cord. There was no evidence of peripheral neuropathy. A comparison between the cyanate induced neuropathy in the rat and in the primate was drawn. Ultrastructurally, both species developed a demyelinating process of central or peripheral myelin characterized by vacuolation of the myelin sheath, removal of myelin debris by macrophages and re-myelination. There was little evidence of axoplasmic damage except for an occasional distended fiber containing abundant dense bodies and whorls of neurofilaments. Oligodendrocytes and Schwann cells were electron microscopically intact and participated actively in remyelination. Maccacas maintained at 15 mg/day and sham animals remained normal clinically and anatomically. The predominantly myelinotoxic effect of cyanate is similar to that produced by other myelinotoxic agents and is attributed to a selective modification of myelin proteins by carbamylation.
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 45 (1979), S. 159-160 
    ISSN: 1432-0533
    Schlagwort(e): Tight junction ; Choroid plexus papilloma ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Four cases of choroid plexus papilloma (CPP) obtained at the time of surgical excision were examined by electron microscopy and compared with normal choroid plexus (CP) of mouse and chick. In apical tight junctions fusion of the two outer leaflets of the adjacent cytoplasmic membrane was verified as in CP. This fact suggests that there is a blood-CSF barrier not only in CP but also in CPP.
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  • 93
    ISSN: 1432-0533
    Schlagwort(e): Visna ; Slow viral infection ; CSF ; Ultrastructure ; Myelin fractions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An electron microscopic examination was done on 8 samples of cerebrospinal fluid (CSF) from Icelandic sheep infected by the intracerebral route with visna virus. The specimens were collected 1 month, 2 months, and 4 years after infection. A differential cell count done on low-power electron micrographs showed that the cellular exudate was composed of mononuclear cells mainly macrophages and lymphocytes with a few plasma cells. Macrophages were with one exception more numerous than lymphocytes and an increased proportion of macrophages showed evidence of phagocytosis with time after infection. Reactive lymphocytes were in general more numerous than small lymphocytes. Various stages in the maturation of plasma cells were observed. The cellular composition in the CSF is compatible with the view that visna is an immunopathological process. Myelin figures and fragments of myelinated axons were observed in two specimens indicating an active myelin-breakdown. The possibility that escape of myelin into the CSF may lead to sensitization to myelin antigens and perpetuation of this chronic neurologic affection is discussed. Visna virions could not be demonstrated.
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 186 (1979), S. 65-70 
    ISSN: 1432-041X
    Schlagwort(e): Sea urchin ; Embryo ; Collagen ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Collagen fibrils with a main period banding of 610 Å and 220 Å in width were observed in the blastocoel of 72-h embryos of the sea urchin,Strongylocentrotus purpuratus. Non-striated fibrils of 50 Å diameter were also observed. The collagen is seen in highest concentration in the vicinity of mesenchyme cells which are richly endowed with endoplasmic reticulum and secretory vesicles. A role for collagen in cell attachment, orientation and spicule formation is discussed.
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 185 (1979), S. 333-346 
    ISSN: 1432-041X
    Schlagwort(e): Chick embryo ; Limb bud ; Ultrastructure ; Cell death
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructural changes in the wing bud afterapical ectodermal ridge (A.E.R.) removal was studied to re-examine the issue of distal mesenchymal cell death. The A.E.R. of the right wing bud was removed microsurgically from chick embryos of stages 18 to 22 (HH 1951). The wing buds were examined at three hour intervals up to twelve hours after the operation with light, transmission and scanning electron microscopy. The main findings were: (1) Immediate and temporary shrinkage of the mesenchymal extracellular space 100 to 150 μm and chromatin condensation in the cells 50 to 75 μm from the wound. (2) Death of ectodermal and mesenchymal cells in the immediate vicinity of the wound. (3) Formation of a single squamous-like layer of mesenchymal cells to cover the wound. (4) Occasional evidence of cell death in the distal mesenchyme at later times after the operation. The pattern of cell death observed suggests only a traumatic etiology, and gives little evidence for the postulated developmental significance of cell death following A.E.R. removal.
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  • 96
    ISSN: 1432-072X
    Schlagwort(e): Methanogenium cariaci ; Methanogenium marisnigri ; Marine methanogenic bacteria ; Ultrastructure ; TaxonomyMethanogenium gen. nov.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A new genus of marine methanogenic bacteria and two species within this genus are described.Methanogenium is the proposed genus andMethanogenium cariaci the type species. Cells of the type species are Gram-negative, peritrichously flagellated, irregular cocci with a periodic wall surface pattern. Colonies formed by these bacteria are yellow, circular and umbonate with entire edges. The DNA base composition is 52 mol% guanine plus cytosine. Formate or hydrogen and carbon dioxide serve as substrates for growth. Cells ofMethanogenium marisnigri are of similar shape but smaller diameter thanM. cariaci. The colonies ofM. marisnigri are convex, and the DNA base composition is 61 mol % G+C. Formate or hydrogen and carbon dioxide are growth substrates. Sodium chloride is required for growth of both methanogens.
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 121 (1979), S. 53-59 
    ISSN: 1432-072X
    Schlagwort(e): Saccharomyces ; Kluyveromyces ; Ultrastructure ; Ascospore wall ; Taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Three types of structure of the ascospore wall were found among the haploid Saccharomyces species examined: a warty wall (S. rouxii), a smooth wall with a single electron-light inner layer (S. bailii) and a smooth wall with a double light inner layer (S. montanus, S. florentinus). The latter type also occurred in Kluyveromyces thermotolerans and K. waltii. In K. fragilis spores the wall had a single light inner layer. The taxonomic implications of these findings were discussed.
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 122 (1979), S. 17-27 
    ISSN: 1432-072X
    Schlagwort(e): Gliding bacteria ; CO2-requiring ; Periodontal disease ; Gram-negative ; Ultrastructure ; Capnocytophaga
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Gram-negative, anaerobic gliding bacteria were isolated from normal supragingival plaque and from periodontal lesions. Isolates could be divided into two size classes: small 2.4–4.2 μm×0.38–0.5 μm and large 4.8–5.8 μm×0.42–0.6 μm cells. The outer membrane was either loose-fitting and wavy, or taut, and of variable thickness. An electron-dense fuzz was discernible on several of the isolates. The periplasmic region was of variable electron-density. The genus Capnocytophaga has been proposed for these organisms based on morphological and cultural characteristics.
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Journal of cancer research and clinical oncology 95 (1979), S. 225-232 
    ISSN: 1432-1335
    Schlagwort(e): Cultured tumour cells ; Ultrastructure ; 3-D Colonies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cultured hepatocellular carcinoma cells were studied during anchorage-independent growth in semi solid medium (Methocel). The regular occurrence of mitotic figures both at the surface and within the colonies precludes the possibility of such colonies being formed by re-aggregation. The estimated population doubling time in the three-dimensional (3-D) colonies is consistent with those two-dimensional of (2-D) colonies. Structures resembling bile canaliculi were observed between the closely opposed membranes from the well packed adjacent cells. Cell surface and ultrastructural features of the colonies and individual cells are presented and comparisons made with 2-D growth of normal and malignant liver cells in vitro. The formation of 3-D colonies may not only be an assay for transformed cells but also for predicting the type of tumors produced by re-innoculation of the in vitro transformed cells.
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 381 (1979), S. 313-329 
    ISSN: 1432-2307
    Schlagwort(e): Bronchial carcinoids ; Different types ; Cells of origin ; Ultrastructure ; Histology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Seven of eleven bronchial carcinoids investigated showed cells with small granules resembling P cells which have already been described in human fetal and adult lung; two of these P cell tumours showed distinctive paraganglioid features. One tumour showed peculiar ultrastructural findings resembling closely those previously reported by Black (1969) in a so called “pulmonary oncocytoma”. Three remaining cases showed large secretory granules resembling those of type 3 cells already described by Hage (1973 b) in bronchial carcinoids; one of these tumours produced large amounts of 5-hydroxytryptamine (5HT). It is concluded that, on cytological grounds, at least two types of tumours can be distinguished among bronchial carcinoids, i.e. P cell and type 3 cell tumours. Moreover, two varieties of P cell carcinoids have been recognized, showing either the less frequent and more distinctive paraganglioid structure or the more common trabecular structure.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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