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  • 1
    ISSN: 1420-908X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 56 (1991), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: Chronic liver failure induced by portocaval anastomosis (PCA) in Wistar rats resulted in a dramatic increase in histamine concentration in hypothalamus and a smaller, but clearly pronounced, elevation in the rest of brain. Between 10 and 120 days following surgery, shunted rats exhibited a histamine level 2.4- to 13-fold higher in hypothalamus and 1.5- to 2.5-fold higher in the rest of brain as compared to their control, sham-operated pairs. There were no significant changes in histamine concentration in the other examined tissues. The increase in brain histamine could not be attributed to the inhibition of its degradation, because activity of histamine N-methyltransferase remained unchanged for at least 40 days. Although the activity of histidine decarboxylase also remained unchanged when measured at a saturating concentration of L-histidine, the increase in histamine content in brain seems to be due to its enhanced synthesis brought about by increased availability of L-histidine in the tissue, as indicated by two to four times higher concentrations of this amino acid in PCA rats.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: HPLC determination of histamine, serotonin, dopamine, and noradrenaline in the brain tissue of rats with portocaval anastomoses (PCA) has revealed a selective increase in histamine concentration. In the posterior hypothalamus, the steady-state level of the amine metabolites showed an inverse pattern; N-tele-methylhistamine(t-MeHA), as estimated by gas chromatography-mass spectrometry, was not changed significantly by portocaval shunting, whereas 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid were more than doubled. Interestingly, the net increase in t-MeHA concentration in response to pargyline (80 mg/kg i.p.) was almost the same for PCA and sham-operated rats. This implies that the great enhancement of the histamine level in this area might be a consequence of the persistent stimulation of its synthesis and the unchanged activity of histaminergic neurons. In the rest of the brain, on the other hand, the steady-state level of t-MeHA was higher after PCA (3.8-fold), as were the levels of 5-HIAA and homovanillic acid. Surprisingly, t-MeHA remained unchanged after monoamine oxidase blockade. Of the pargyline-induced alterations in the concentrations of indoles and catechols, the most pronounced were those in the serotonin level; serotonin was elevated more than twofold in hypothalamus and more than 12-fold in the rest of the brain, with a concomitant 80% decrease in 5-HIAA. The dopamine and, to a much smaller extent, noradrenaline levels were also increased, and the levels of homovanillic acid and 3,4-dihydroxyphenylacetic acid fell below the detection limit. The study suggests that at least two different mechanisms operate in the brains of PCA rats to counteract the excessive synthesis of neuromediators, e.g., increased deposition and increased metabolism.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 752 (1995), 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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  • 5
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Rats with portocaval anastomosis (PCA), an animal model of hepatic encephalopathy (HE), have very high brain histamine concentrations. Our previous studies based on a biochemical approach indicated histamine accumulation in the neuronal compartment. In this study, immunohistochemical evidence is presented which further supports the amine localization in histaminergic neurons. These neurons become pathological in appearance with cisternae frequently seen along histaminergic fibres in many brain areas, including the hypothalamus, amygdala, substantia nigra and cerebral cortex. Such formations were not observed in sham-operated animals. The neuronal deposition is predominant, and unique for histamine. It serves as a mechanism to counterbalance excessive brain neurotransmitter formation evoked by PCA. However, there are other mechanisms. The data provided here show that there is also a significant increase in histamine catabolism in the shunted rats, as reflected by both the higher brain N-tele-methylhistamine (t-MeHA) concentration and urinary excretion of N-tele-methylimidazoleacetic acid (t-MeImAA), a major brain histamine end product. The stomach, in addition to the brain, is a site of enhanced histamine synthesis in portocavally shunted subjects. After gastrectomy or food deprivation to eliminate the contribution of the stomach, shunted rats excrete significantly more t-MeImAA, implying the role of the CNS. This last finding suggests that under strictly defined conditions, namely in parenterally fed HE patients with abnormal plasma l-histidine, the measurement of urinary t-MeImAA might provide valuable information concerning putative brain histaminergic activity.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    ISSN: 1420-908X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Diamine oxidase activity and imidazoleacetic acid formation in the foetal and maternal guinea pig liver during gestation were examined. DAO activity and IMAA formation in the foetal liver increased continuously, while maternal enzyme activity and ImAA formation in the second half of pregnancy simultaneously decreased. The roles of GABA and ImAA are discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    ISSN: 1433-0407
    Schlagwort(e): Schlüsselwörter Tremor ; Elektromyographie ; Ablenkmanöver ; Key words Tremor ; Electromyography ; Distraction maneuvers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary In a total of 30 tremor patients (14 with Parkinson’s disease, 6 with cerebellar tremor, 4 with essential tremor, 4 with psychogenic tremor, 2 with enhanced physiological tremor), tremor was electromyographically recorded before, during and after contralateral distraction tasks (tapping with the index finger or the tip of the foot, sequential flexion of the 2nd to 5th finger towards the thumb, „keyboarding”, and sensory discrimination). 22 of 26 patients with organic tremors spontaneously choose a volitional tapping frequency independent from their tremor frequency. In 4 patients with psychogenic tremor, frequencies of tremor and tapping were locked (n=3), or tremor disappeared abruptly (n=1) when contralateral tapping was started. Contralateral „keyboarding” and sensory discrimination revealed no clear differences between organic and psychogenic tremors. Contralateral tapping in further 23 patients (22 with organic tremors and 1 with psychogenic tremor) confirmed these findings. Contralateral tapping appears as the most valid distraction task and may help to differentiate psychogenic from organic tremors.
    Notizen: Zusammenfassung Bei insgesamt 30 Patienten mit Tremor (14 mit Parkinson-Tremor, 6 mit zerebellärem Tremor, 4 mit essentiellem Tremor, 4 mit psychogenem Tremor, 2 mit aktiviertem physiologischen Tremor) wurde die Tremoraktivität vor, während und nach folgenden kontralateralen Ablenkungsmanövern elektromyographisch abgeleitet: Taktschlagen mit dem Zeigefinger oder der Fußspitze, sequentielle Beugung des 2. bis 5. Fingers auf den Daumen („Klavierspielen”) und Zahlendiskrimination. 22 von 26 Patienten mit organischem Tremor wählten spontan eine von der Tremorfrequenz abweichende willkürliche Taktfrequenz. Bei 4 Patienten mit psychogenem Tremor dagegen standen Tremor- und Taktfrequenz entweder in einer ganzzahligen Beziehung (n=3) oder der Tremor brach abrupt mit Taktbeginn ab (n=1). Während kontralateralem „Klavierspielen” und kontralateraler Zahlendiskrimination fanden sich dagegen keine klaren Unterschiede zwischen organischen und psychogenen Tremores. Die Befunde beim kontralateralen Taktschlagen wurden bei weiteren 23 Patienten (22 mit organischem Tremor und 1 mit psychogenem Tremor) bestätigt. Kontralaterales Taktschlagen erscheint danach als valider klinischer Test für die Abgrenzung psychogener von organischen Tremores.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Inflammation research 23 (1988), S. 304-306 
    ISSN: 1420-908X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The response of intestinal mucosal enzymes which metabolize histamine i.e. diamine oxidase (DAO), histamine N-methyltransferase (HMT), and monoamine oxidase (MAO), to infection withNippostrongylus brasiliensis has been examined in mice and compared to the changes evoked byin vivo administration of compound 48/80. Infection with the parasite resulted in a significant decrease in the concentration of both amine oxidases, followed by recovery of MAO and an overshoot in DAO activity. HMT activity was enhanced at the beginning of infection, then decreased markedly by days 11 to 15, and sharply increased thereafter. Histamine levels were on average only 20% higher than the basal levels over the entire period studied, except on day 4 when they were slightly reduced. Histamine is alleged to be a potential inducing factor for degrading enzymes. Consistently, the histamine releaser 48/80 significantly elevated intestinal mucosal DAO and in some of the mice also increased HMT activity.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1420-908X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Inflammation research 49 (2000), S. 45-46 
    ISSN: 1420-908X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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