Results 241 to 250 of about 11,930 (298)

Dihydroxyphenylalanine in Extrapyramidal Disease

JAMA: The Journal of the American Medical Association, 1963
EVIDENCE has been accumulating for the past several years which has implicated dopamine metabolism in the production of extrapyramidal symptoms. Drugs such as reserpine which tend to produce extrapyramidal symptoms as a side effect have been shown to deplete dopamine from the brain.
A J, FRIEDHOFF, L, HEKIMIAN, M, ALPERT, E, TOBACH   +3 more
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Neuronal Source of Plasma Dihydroxyphenylalanine

The Journal of Clinical Endocrinology & Metabolism, 1987
The source and significance of plasma levels of dihydroxyphenylalanine (DOPA), the precursor of the endogenous catecholamines, have been unknown. We measured arterial and venous plasma DOPA concentrations in healthy subjects at rest, patients who had undergone regional sympathectomies or were undergoing general anesthesia, and subjects during ...
DAVID S. GOLDSTEIN, ROBERT UDELSMAN, GRAEME EISENHOFER, ROBIN STULL, HARRY R. KEISER, IRWIN J. KOPIN, CAROL JOAN FOLIO   +6 more
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On the presence of dihydroxyphenylalanine decarboxylase in nerves

Experientia, 1964
Durchtrennung des Ruckenmarks fuhrt zu einer Verminderung der Aktivitat des Enzymsl-3,4-Dihydroxyphenylalanin-decarboxylase (DOPA-Decarboxylase) in den kaudalen Teilen um 75% (in-vivo-Werte) bis 95% (in-vitro-Werte). Die Decarboxylaseaktivitat in der Rattenmilz wird nach Exzision des Ganglion Coeliacum ebenfalls erheblich vermindert.
N E, Andén, T, Magnusson, E, Rosengren
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Decarboxylation of 3,4-dihydroxyphenylalanine by oxyhemoglobin

Biochemical and Biophysical Research Communications, 1972
Abstract A lysate of red blood cells catalyzes the decarboxylation of 3,4-dihydroxyphenylalanine. This activity appears to be due to a reaction with oxyhemoglobin and not the presence of aromatic L amino acid decarboxylase in erythrocytes.
H, Yamabe, W, Lovenberg
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Dihydroxyphenylalanine secretion in a malignant pheochromocytoma

The American Journal of Medicine, 1967
Abstract Studies on catecholamine metabolism in patients with neural crest tumors revealed a high plasma level of 3,4-dihydroxyphenylalanine (dopa) and dopamine (DM) in association with a malignant, but not a benign pheochromocytoma. The large amounts of these amines may have been mistaken in other studies for norepinephrine because of the use of a ...
A H, Anton, M, Greer, D F, Sayre, C M, Williams   +3 more
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Chemiluminescence in the autooxidation of dihydroxyphenylalanine

Bulletin of the Academy of Sciences of the USSR Division of Chemical Science, 1972
1. In the oxidation of dihydroxyphenylalanine in alkaline medium, chemiluminescence was detected in the region of 450–600 nm with a maximum at 530 nm. The step of cyclization, leading to the formation of 5,6-dihydroxyindole, proved responsible for the luminescence. 2.
G. N. Bogdanov, V. N. Shtol'ko
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Origin and Significance of Plasma Dihydroxyphenylalanine

1997
Publisher Summary This chapter summarizes the origin and the significance of plasma 3,4-Dihydroxyphenylalanine (DOPA). DOPA is both a catecholamine and an aromatic amino acid. DOPA occupies a central position in the function of the sympathetic nervous system. It is the immediate product of the rate-limiting step in the biosynthesis of catecholamines:
Eldrup, Ebbe, Richter, Erik A., Hetland, Merete L., Andreasen, Jan, Hilsted, Jannik, Møller, Svend E., Christensen, Niels Juel   +6 more
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The metabolism of L-3,4-dihydroxyphenylalanine in man

Clinica Chimica Acta, 1970
Abstract This study describes the metabolic fate of orally ingested l -3,4-dihydroxy-phenylalanine in four human adults. The amounts of L-DOPA ingested ranged from 3 to 8 g per day. A variety of techniques were employed whereby the acid, amine, and neutral urinary metabolites were determined.
L P, O'Gorman, O, Borud, I A, Khan, L R, Gjessing   +3 more
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Enzymatic decarboxylation of isomers and derivatives of dihydroxyphenylalanine

Archives of Biochemistry and Biophysics, 1952
Abstract 1. 1. The substrate specificities of tyrosine decarboxylase of Streptococcus faecalis R and of dihydroxyphenylalanine (DOPA) decarboxylase of pig and guinea pig kidney have been studied. 2. 2. The quantitative data reveal that interaction between substituents on the benzene ring of the substrates, as well as the position of the ...
T, SOURKES, P, HENEAGE, Y, TRANO
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3, 4-Dihydroxyphenylalanine and Related Compounds

1966
This review covers essentially derivatives of β-phenyl-α-alanine which contain two phenolic hydroxyl groups, and some of their analogs and derivatives. They comprise β-(3, 4-dihydroxyphenyl)-α-alanine (dopa) and the few known ethers and ring substituted derivatives of this amino acid, as well as derivatives of dopa substituted in the alanine group ...
A R, Patel, A, Burger
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