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  • 1
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 419-421 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A new type of optical bistable device is demonstrated. We report the first observation of optical bistable switching caused by charge-induced self-feedback due to field screening in GaAs/AlGaAs multiple quantum well structures, both at room temperature and at low temperature (110 K). A bias voltage supply is directly connected to the p-i-n diode with the multiple quantum well structure to attain optical bistability. Since no external series resistance is required, the device is attractive from the standpoint of a practical application. The mechanism for the self-feedback underlying the operation of the device is elaborated. The theoretical consideration about the resolvable spot size on the device operation is shown.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 16 (1969), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract— The fourth ventricle of the cat was perfused and the release of γ-aminobutyric acid (GABA) into the perfusate was measured. GABA was released at a rate of 6·69 × 10−10 moles/min and increased about three times during cerebellar cortical stimulation at 200/sec. It is suggested that GABA is released from axon terminals of Purkinje cells in cerebellar subcortical nuclei.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 18 (1971), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract— A sensitive method for measuring γ-aminobutyric acid (GABA) has been developed. This method consists of a combination of the enzymic GABA assay of Jakoby and Scott (1959) with the enzymic cycling technique of Lowry, Passonneau, Schulz and Rock (1961) and permits the measurement of as little as 2 × 10−14 mol of GABA. Using this method, GABA analyses were made on single isolated nerve cell bodies of different types from the CNS of the cat. Average GABA concentrations in these cell bodies were: spinal ganglion cells, 0.2 mm; spinal mononeurons, 0.9 mm; large cells of the ventral part of Deiters' nucleus, 2.7 mm; large cells of the dorsal part of Deiters’ nucleus, 6.3 mm; cerebellar nuclei cells, 6.0 mm; cerebellar Purkinje cells, 6.6mM; cerebral Betz cells, 2.5 mm.The GABA concentrations in the isolated dorsal Deiters' cells were greatly reduced (1.7 mm) after the removal of the cerebellar vermis while those of the ventral Deiters' cells were unaffected by the denervation. These results suggest that GABA is concentrated within axon terminals, probably of Purkinje neurons, synapsing with the dorsal Deiters' cells. The results of GABA analyses on isolated nerve cells are discussed in relation to the relevant neuronal functions and the possible role of GABA as an inhibitory transmitter.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 17 (1970), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 11 (1999), S. 0 
    ISSN: 1460-9568
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: To elucidate the physiological role of Fyn, we analysed the properties of synaptic transmission and synaptic plasticity in hippocampal slices of mice overexpressing either wild-type Fyn (w-Fyn) or its constitutively active mutant (m-Fyn). These fyn-transgenes were driven by the calcium/calmodulin-dependent protein kinase IIα promoter which turned on in the forebrain neurons including hippocampal pyramidal cells and in late neural development. In the hippocampal slices expressing m-Fyn the paired-pulse facilitation was reduced and the basal synaptic transmission was enhanced. A weak theta-burst stimulation, which was subthreshold for the induction of long-term potentiation (LTP) in control slices, elicited LTP in CA1 region of the slices expressing m-Fyn. When a relatively strong stimulation was applied, the magnitude of LTP in m-Fyn slices was similar to that in control slices. By contrast, the basal synaptic transmission and the threshold for the induction of LTP were not altered in the slices overexpressing wild-type Fyn. To examine the effect of expression of m-Fyn on GABAergic inhibitory system, we applied bicuculline, a GABAA receptor blocker, to the hippocampal slices. The ability of bicuculline to enhance excitatory postsynaptic potentials was attenuated in slices expressing m-Fyn, suggesting that the overexpression of m-Fyn reduced the GABAergic inhibition. The enhancement of synaptic transmission and the reduction of GABAergic inhibition may contribute to the enhanced seizure susceptibility in the mice expressing m-Fyn. Thus, these results suggest that regulation of Fyn tyrosine kinase activity is important for both synaptic transmission and plasticity.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1460-9568
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: In the present study we further investigate functions of the neural cell adhesion molecule (NCAM) in the mature central nervous system and its implications for animal behaviour. To this end we generated transgenic mice expressing the major NCAM isoform with the largest cytoplasmic domain, NCAM180, under control of a promoter for the small form neurofilament gene. Transgenic mice were also bred with mice deficient in endogenous NCAM (Ncam–/– mice) so that effects of NCAM180 could be analysed in the presence and absence of endogenous NCAM. While overexpression of transgenic NCAM180 was without apparent behavioural or morphological effect, its expression in Ncam–/– mice counteracted NCAM ablation-induced aggressive, anxiety-like and antidepressant-like behaviour. It furthermore prevented a hypersensitivity of Ncam–/– mice to the anxiolytic serotonin1A (5-HT1A) receptor agonist buspirone. Such recovery of emotional behaviour and behavioural 5-HT1A response occurred in spite of misdevelopment of the olfactory bulb and hippocampus that is characteristic of Ncam–/– mice, and without an apparent change in the expression of 5-HT1A binding sites in the brain. Hippocampus- and amygdala-dependent learning, though disturbed in Ncam–/– mice, remained unaffected by the transgenic NCAM180. We suggest an involvement of NCAM180-mediated cell recognition processes in the serotonergic modulation of emotional behaviour in adult mice.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1600-0536
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Closed patch testing and the nitrocellulose replica method are performed as useful clinical methods for the evaluation of human skin irritation by cosmetics and topical medicaments. Comparison of the sensitivity between microscopic scoring by nitrocellulose-replica method and visual scoring by closed patch test in the detection of skin irritation, however, has not been well studied with statistical analysis. Here, we evaluated human skin irritation by carboxylic acids. Alcohols, esters and aldehydes, with different chain length (C8-C18), using both methods. The results of closed patch testing showed that, although the score of skin irritation for carboxylic acids (C8, C12), alcohols (C8) and aldehydes (C8), tested at a concentration of 0.5 m-2.0 m. significantly increased with increasing concentration of the test compounds, ester compounds scarcely caused any irritation on the surface of the skin occluded. In addition, an increase of carbon chain length in the test compounds made it impossible to detect skin irritation. In contrast, the nitrocellulose-replica method could evaluate skin reactions against very weak irritants that gave no macroscopic alterations on the skin surface in the closed patch test. However, the scoring system is somewhat subjective and should be improved to make the analysis more objective.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 801 (1996), S. 0 
    ISSN: 1749-6632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    ISSN: 1442-2042
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Melbourne, Australia : Blackwell Science Pty
    Nephrology 5 (2000), S. 0 
    ISSN: 1440-1797
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: We compared an antiproteinuric effect of a lipid-lowering agent probucol on two distinct types of experimental nephrosis in rats, i.e. mercuric–chloride (HgCl2)-induced autoimmune glomerulonephritis in Brown Norway (BN) rats and puromycin aminonucleoside (PA)-nephrosis in Wistar rats. The rats were fed either standard rat chow or chow containing 5% probucol. BN rats were treated with HgCl2 according to a standard protocol (HgCl2 1 mg/kg subcutaneously three times/week). Probucol treatment did not ameliorate proteinuria, renal histology or a strong linear staining for IgG and an intercellular adhesion molecule, ICAM-1, in glomeruli. Wistar rats were made nephrotic with an intraperitoneal injection of PA (100 mg/kg). In this model, in contrast to the BN rat model, no glomerular deposition of IgG or ICAM-1 was observed. Probucol treatment ameliorated proteinuria significantly. These findings suggest that the response to probucol differs in different experimental nephrosis models. As probucol only affects PA-nephrosis, in which ICAM-1 expression is negative, the ICAM-1 attenuation is not likely to be involved in the antiproteinuric effect of probucol.
    Materialart: Digitale Medien
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