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  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 131-133 (Oct. 2007), p. 119-124 
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: The degradation and recovery behavior of device performance on GaAlAs LEDs (Lightemitting diodes) irradiated by 2-MeV electrons and 70-MeV protons are investigated. The reversecurrent increases after irradiation, while the capacitance decreases. The device performancedegradation is proportional with fluence. For electron irradiation, fluence rate is also effective fordegradation. Low fluence rate shows more large degradation compared to high fluence rateresulting from heat impact in bulk. DLTS measurement reveals the DX center in epitaxial substrate,and this spectrum increases with fluence. The radiation damage of proton is larger than that ofelectron irradiation, which is caused by the difference of mass and possibility of nuclear collisionfor the formation of lattice defects. After irradiation, the device performance recovers by thermalannealing
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 95-96 (Sept. 2003), p. 381-386 
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0942-0940
    Keywords: Subarachnoid haemorrhage ; chronic cerebral vasospasm ; calcium antagonist ; AT877 ; HA 1077
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The initial dose-escalating clinical trial of a novel calcium antagonist, AT877, in patients with aneurysmal subarachnoid haemorrhage is reported. AT877 is characterized by its strong spasmolytic activity, its inhibition of intracellular calcium ion activity, and the inhibiton of several protein kinases. A total of 113 patients (Hunt and Hess grades I to IV) who had undergone surgery within 3 days of aneurysmal rupture entered the study. Patients were divided into 5 groups according to the total daily dose of AT877: I: 20 mg; II: 40 mg; III: 60 mg; IV: 90 mg; and V: 120–180 mg. AT877 was given by intravenous infusion over 30 min two or three times a day for 14 days after surgery. Although AT877 did not completely abolish angiographic vasospasm, severe vasospasm was seen less frequently in patients given higher doses. Vasospasm was the cause of a poor clinical outcome (Glasgow outcome scale rating 3 or greater) in 19%, 7%, 9%, 8%, and 6% of the patients in groups I to V, respectively. The results indicated a favourable clinical effect of AT877 at doses above 40 mg per day. Only mild hypotension was seen, even when 60 mg of AT877 was infused over 30 min. AT877 appears to be effective in patients with subarachnoid haemorrhage. Part of its effect may be attributable to protection of the brain from ischaemic insults due to chronic cerebral vasospasm. However, the drug still needs to be evaluated in a placebo-controlled double-blind trial (which is currently being carried out).
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 109 (1991), S. 34-36 
    ISSN: 0942-0940
    Keywords: Ganglioside GD3 ; glioma ; shedding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The proportion of ganglioside GD3 increases in glioma tissue and GD3 content is correlated with malignancy of gliomas. This ganglioside can be detected in the sera of patients with glioma by thin-layer chromatographic analysis. Ganglioside GD3 was not detected in the sera of healthy donors and astrocytoma grade 2 patients. However, serum GD3 was detected in one of three astrocytoma grade 3 patients and seven of nine glioblastoma patients. These results show that shedding of GD3 increases in proportion to the degree of malignancy of gliomas. Nevertheless, all of the glioblastoma patients in this study were advanced cases. Considering the high reliability of radiological diagnostic techniques in the neurosurgical field, further study will be necessary to clarify the relationships between the GD3 level in serum and the properties of tumours.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0533
    Keywords: Ferritin labeled lectin ; Human pituitary adenoma ; Functioning adenoma ; Non-functioning adenoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Lectin-binding sites of the human pituitary adenoma cells were examined by electron microscopy in correlation with their functional states. In this study used were 37 cases of the human pituitary adenomas which had been operated in our clinics from 1977 to 1979. They were divided into four groups: 13 cases of PRL-producing adenomas, nine of hGH-producing adenomas, three of ACTH-producing adenomas, and 12 of hormonal non-functioning adenomas. In parallel with the detection of the lectinbinding sites by means of the ferritin-labeling method, the basal levels of their secreting hormones were determined by the radioimmunoassay technique, and their producing hormones were characterized light microscopically by the immunocytochemical HRP-labeling technique. The present study clearly shows that the ferritinlabeled, lectin-binding sites of the human pituitary adenoma cells prefixed with aldehyde are different in number between PRL- or hGH-producing adenoma cells and non-functioning ones. Morphologically resemblin, non-functioning adenoma cells and mixed somatotrophic and lactotrophic adenoma cells are definitely distinguished from each other by the findings of the ferritin-labeled RCA-binding sites' distribution pattern. Lectins have been proved very useful to evaluate the membrane characteristics of the human pituitary adenoma cells in association with their functional states.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0533
    Keywords: Capillary endothelium ; Outer leaflet ; Mitochondria ; Arachidonic acid ; Vasogenic edema
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A peculiar ultrastructural change of the cytoplasmic membrane is described. It concerns selective destruction of the outer leaflet of the luminal side of the capillary endothelium in the white matter of the rat brain. 30 min and 3h after intracerebral injection of arachidonic acid (AA). The cristae of the mitochondria disappeared in the endothelium of many capillaries. These changes were observed mainly in the central part of brain edema, where the extracellular space was markedly widened. The possible mechanism whereby these changes developed is discussed.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0533
    Keywords: Horseradish peroxidase ; Concanavalin A ; Human pituitary adenoma ; Functioning adenoma ; Non-functioning adenoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intracellular lectin (Con A)-binding sites of human pituitary adenoma were examined by electron microscopy using the horseradish-peroxidase (HRP)-labelling technique. In this study were used 16 cases of human pituitary adenomas operated on in our clinics between 1977 and 1981: they concluded 4 each of PRL-, GH-, ACTH-producing and hormonal non-functioning adenomas. In parallel with the detection of lectin-binding sites, basal levels of their secreting hormones were determined by the radioimmunoassay technique, and their producing hormones were characterized light microscopically by the immunocytochemical HRP-labelling technique. In the present study, for hormonal functioning adenoma cells, mature or large granules of each specific type of adenoma cells had no definite Con A-binding sites. On the other hand, immature or small secretory granules of RPL- or GH-producing adenoma cells showed a positive reaction with Con A. ACTH-producing adenomas so far examined revealed no definite binding sites. Some variable results were obtained concerning non-functioning adenomas. Lectins have been and will be very useful in the detection of different subtypes of adenomas in each specific group.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0942-0940
    Keywords: Meningioma ; venous stasis ; brain oedema
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Many factors have been suggested as possible mechanisms for the development of peritumoural oedema in meningioma. Venous compression by the tumour is thought to be one factor, but reports presenting a direct relationship between venous compression and the formation of oedema are rare. We have recently observed 6 meningioma patients in whom venous stasis contributed to peritumoural oedema. The stasis was due to 1) compression of an adjacent cortical vein by the tumour with stasis at the site of compression and/or its distal portion. 2) compression of adjacent brain by the tumour with prolonged perfusion and delayed venous return (visualized as pial staining in the capillary and venous phases), and 3) presence of an early draining vein linked to a nearby cortical vein with stasis at its periphery. Venous compression and stasis seem to be related not only to the formation of peritumoural oedema but also to the occurrence of haemorrhagic infarction after the resection of meningiomas.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Acta neurochirurgica 93 (1988), S. 10-12 
    ISSN: 0942-0940
    Keywords: Insulin receptors ; glioma cells ; DNA synthesis ; RNA synthesis ; protein synthesis ; 3H-thymidine ; 3H-uridine ; 3H-leucine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The existence of insulin receptors and biological responces to insulin on macromolecular synthesis have been studied in C6 glioma cells. Binding of125I-insulin to C6 glioma cells was specific, time-and PH-dependent. Porcine insulin competed for1125I-insulin binding in a dose-dependent manner. Unlabeled polypeptides, including glucagon, bovine growth hormone, bovine prolactin did not compete for125I-insulin binding. Scatchard analysis of the binding data gave a curvilinear plot which may indicate negative co-operativity or the existence of both high and low affinity (Ka=7.55 × 1010 −4.25 × 109) sites. Incubation of cultures with insulin caused a time and dose-dependent stimulation of DNA, RNA and protein synthesis in C 6 glioma cells (measured by3H-thymidine,3H-uridine or3H-leucine incorporation into DNA, RNA, or protein respectively). The increase of macromolecular synthesis was admitted at more than 2 nM concentration of insulin. Maximal stimulation of DNA synthesis (142% of control) occurred 6 hours after incubation with 167 nM insulin. The same concentration of insulin caused a 45% increase in 1 hour on RNA synthesis, a 37% increase in 2 hour on protein synthesis. These results indicate that C 6 glioma cells have specific insulin receptors capable of mediating effects of insulin on macromolecular synthesis. Insulin in the brain and even blood may be an important growth factor in the glioma cells of the patients with disrupted bloodbrain-barrier.
    Type of Medium: Electronic Resource
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