Results 321 to 330 of about 44,980 (368)

Novel 1,3-disubstituted 8-(1-benzyl-1H-pyrazol-4-yl) xanthines: high affinity and selective A2B adenosine receptor antagonists.

Journal of Medicinal Chemistry, 2006
Adenosine has been suggested to induce bronchial hyperresponsiveness in asthmatics, which is believed to be an A(2B) adenosine receptor (AdoR) mediated pathway.
Rao V Kalla, E. Elzein, Thao D Perry, Xiaofen Li, V. Palle, V. Varkhedkar, A. Gimbel, Tennig Maa, D. Zeng, J. Zablocki   +9 more
semanticscholar   +1 more source

A novel synthesis of xanthines: support for a new binding mode for xanthines with respect to adenosine at adenosine receptors.

Journal of Medicinal Chemistry, 1990
Le nouveau mode de liaison propose est corrobore par des comparaisons de charges atomiques partielles, par une modelisation moleculaire, et une nouvelle synthese des xanthines, permettant l'introduction d'une unite de reconnaisance chirale en position ...
N. Peet, N. L. Lentz, E. Meng, M. W. Dudley, A. Ogden, D. Demeter, H. Weintraub, P. Bey   +7 more
semanticscholar   +1 more source

Xanthine urolithiasis in a dachshund

Veterinary Record, 1998
Calculi were located in the kidneys, the ureters and the bladder of a two‐year‐old male dachshund. The yellow‐greenish calculi developed as a result of impaired transformation of xanthine to uric acid resulting in an increased concentration of xanthine in the urine.
R. Freistadt, T. Flegel, W. Haider
openaire   +3 more sources

Inhibition of separated forms of cyclic nucleotide phosphodiesterase from pig coronary arteries by 1,3-disubstituted and 1,3,8-trisubstituted xanthines.

Journal of Medicinal Chemistry, 1981
A series of xanthines with varied substituents in the 1, 3, and 8 positions were prepared in an attempt to understand the structure--activity relationship for alkylxanthines as inhibitors of two different forms of cyclic nucleotide phosphodiesterase ...
J. N. Wells, J. Garst, G. L. Kramer
semanticscholar   +1 more source

Measurements of solubilities of xanthines in supercritical carbon dioxide+methanol

, 1995
Solubilities of the xanthines caffeine, theophylline, and theobromine in different supercritical (carbon dioxide + methanol) mixtures were measured at 313 K and 22 MPa.
M. Johannsen, G. Brunner
semanticscholar   +1 more source

Xanthine Oxidase Studies†

Journal of the American Pharmaceutical Association (Scientific ed.), 1952
An investigation was undertaken of the effect on the purine metabolism of the rat of 2-amino-4-hydroxy-6-formyl pteridine, known to inhibit xanthine oxidase, and sodium bromide, reported to retard uricopoiesis. Neither the intraperitoneal administration of the pteridine nor the oral administration of sodium bromide significantly lowered the tissue ...
openaire   +3 more sources

Structure-activity relationship of xanthines and skeletal muscle ryanodine receptor/Ca2+ release channel.

Pharmacology, 1997
Caffeine (1,3,7-trimethylxanthine) in the millimolar range is known to activate the skeletal muscle Ca2+ release channel (ryanodine receptor). Xanthine analogs substituted in the 1, 3, 7, 8 and 9 positions were tested for their capacity to increase [3H ...
W. Liu, G. Meissner
semanticscholar   +1 more source

Determination of xanthines by high-performance liquid chromatography and thin-layer chromatography in horse urine after ingestion of Guaraná powder.

In Analysis, 1994
The seeds of Guaraná are rich in xanthines and are used for the preparation of guaraná powder which is very commonly given to horses as a 'tonic' in Brazil.
Myriam C. Salvadori, Evelyn M. Rieser, L. M. R. Neto, Elizabeth de Souza Nascimento   +3 more
semanticscholar   +1 more source

THE XANTHINES (THEOBROMINE AND AMINOPHYLLINE) IN THE TREATMENT OF CARDIAC PAIN

, 1937
An endeavor was made in this study to secure evidence on the question of whether the xanthines relieve cardiac pain. SELECTION OF PATIENTS The subjects were 100 ambulant patients in attendance at the cardiac clinic, in whom the diagnosis of ...
H. Gold, N. Kwit, H. Otto
semanticscholar   +1 more source

An automated HPLC assay for simultaneous quantitation of methylated xanthines and uric acids in urine.

Journal of Chromatographic Science, 1982
To investigate the elimination kinetics of caffeine and its metabolites, as well as the interaction between them, an automated HPLC method is described. This method involves a single extraction procedure, followed by a gradient elution.
D. Tang-Liu, S. Riegelman
semanticscholar   +1 more source