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  • 1970-1974  (22)
  • 1965-1969  (4)
  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 19 (1972), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract— Administration of l-histidine at the rate of 500 mg/kg induced an increase of nearly 50 per cent in the level of histamine in rat brain which lasted several hours. The augmentation of histamine level was not significant 3 h after lower doses or after d-histidine α-methyl DOPA and Ro 4-4602 neither affected the cerebral level of histamine nor its elevation induced by l-histidine. Brocresine, a known histidine decarboxylase inhibitor not only prevented the effect of histidine load but also induced a prompt fall in the amine level. These results confirm those from earlier experiments in vitro indicating that histamine synthesis in rat brain depends on a specific decarboxylase (EC 4, 1.1.22) which is not normally saturated by the endogenous level of its substrate.When histamine levels were enhanced by histidine treatment, histidine decarboxylase activity, as evaluated on hypothalamus homogenates, was significantly reduced; intracisternal administration of cycloheximide, an inhibitor of protein synthesis, had similar effects. On the other hand, enzyme activity was not altered by the addition of histamine to hypothalamus homogenates. These results are compatible with the existence of a regulation mechanism of histidine decarboxylase involving repression by its end-product.
    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 20 (1973), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract— The mechanism of histamine methyltransferase (HMT) inhibition by S-adenosylhomocysteine (SAH) has been investigated on a partially purified enzyme from guinea-pig brain. The kinetic data indicated that this inhibition was competitive with respect to S-adenosylmethionine (SAMe) and noncompetitive with respect to histamine. The Kt, values (about 5 ± 10−6 M in both cases) indicated that SAH had a higher affinity than SAHe or histamine for the enzyme.In rats, after administration of a small dose of SAH, methylation of intracisternally injected [3H]histamine was not modified.However, treatment with l-DOPA or pyrogallol induced a decrease in [3H]histamine methylation, presumably due to a modification in the SAMe/SAH ratio in the brain. Hence, histamine methylation in brain could be regulated according to the value of this ratio and thus related to methylation of other biogenic amines.
    Materialart: Digitale Medien
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  • 3
    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
    Notizen: —Properties of the histamine-forming enzyme in rat brain were studied, utilizing a sensitive fluorometric assay. The optimum pH was related to substrate concentration and found to be6·4 at 10−2m-histidine; the apparent Km was about 4·10−4m; enzyme activity was inhibited by α-hydrazino -histidine and brocresine but was not affected by α-methyl DOPA or benzene. These different data suggest that the 'specific’histidine decarboxylase (EC 4.1.1.22)—and not the aromatic l-aminoacid decarboxylase—is involved. Determination of enzyme activity and histamine level in different areas of the rat brain revealed important regional differences, the two values being roughly parallel.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 21 (1973), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract— The subcellular distribution of histidine decarboxylase (assayed by two different isotopic methods) and several biochemical markers (lactate dehydrogenase, DOPA decarboxylase and protein) was determined in rat cerebral cortex. After differential centrifugation, the enzyme activity was found mainly in the crude mitochondrial and soluble fractions. Further separation of the former on discontinuous sucrose gradients showed that the particulate histidine decarboxylase (HD) was found in the synaptosomal fraction. After osmotic shock, HD activity appeared in the supernatant fraction suggesting that a major portion of the enzyme is localized in the cytoplasm of cortical nerve endings. By analogy with other brain amines, this finding, together with the presence of histamine in synaptic vesicles (Kataoka and de Robertis, 1967), can be taken as further support for the hypothesis of a role as neurotransmitter for histamine.Various brain regions were homogenized under conditions leading to synaptosome formation. The distribution of HD between ‘particulate’ and soluble fractions differed from one region to the other, but did not give any clear-cut indication of regions rich in cell bodies or nerve terminals.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    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
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Medicine 19 (1968), S. 269-282 
    ISSN: 0066-4219
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of organic chemistry 39 (1974), S. 1575-1583 
    ISSN: 1520-6904
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 30 (1974), S. 0 
    ISSN: 1398-9995
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 33 (1968), S. 0 
    ISSN: 1750-3841
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: SUMMARY— Kennebec and Red Pontiac potatoes were analyzed for fatty acids at intervals during growth and maturation of the tubers and subsequent storage at 4°C. During storage linoleic and linolenic were almost the only polyunsaturated acids present, but during growth and maturation considerable amounts of unidentified polyunsaturated acids were found. The percentage of polyunsaturated acids in the dry weight of tuber decreased to a low value near harvest time and remained near this value throughout the 6.3-month storage period, except that the value in Pontiacs stored 19 days was somewhat high. The percent of polyunsaturates in the total fatty acid fraction also dropped to a low value during growth and maturation but increased somewhat during storage. For this reason it may be better, when practicable, to make dehydrated products from freshly-harvested rather than from stored potatoes.Potato dice contained as much polyunsaturated acid as the tubers they were made from; potato flakes contained somewhat less. In both products the degree of unsaturation of the fatty acid fraction was the same as for the tubers. NO off-flavors were noticed when samples were reconstituted. Apparently little or no oxidation took place during the processing.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 248 (1974), S. 84-85 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] We use the methods of Jinks and Fulker for our evaluation. The difference in correlation coefficients for identical twins raised together (MZ) and fraternal twins raised together (DZ) is where In general £'1(DZ)〉 E^MZ) since identical twins are treated more similarly than fraternal twins. ...
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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