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Biomedical subjects

R Parker

Publications and source records attributed to R Parker.

At least 271 records · Page 15Linked to original sources
PubMed1969

The conversion of 4-hydroxypyrazolo[3,4-d]pyrimidine (allopurinol) into 4,6-dihroxypyrazolo[3,4-d]pyrimidine (Oxipurinol) in vivo in the absence of xanthine-oxen oxidoreductase.

1. A patient with congenital deficiency of xanthine oxidase (EC 1.2.3.2) (xanthinuria) excreted the xanthine isomer 4,6-dihydroxypyrazolo[3,4-d]pyrimidine (oxipurinol) in his urine when the hypoxanthine isomer 4-hydroxypyrazolo[3,4-d]pyrimidine (allopurinol) was given by mouth. 2. The identity of the oxipurinol that the patient excreted was established by mass spectrometry. 3. The mass spectra and infrared spectra of allopurinol, oxipurinol, hypoxanthine and xanthine are compared. 4. A mechanism for the fragmentation of these compounds that occurs during their mass-spectrometric investigation is proposed. 5. A possible metabolic pathway for the oxidation of allopurinol to oxipurinol in the absence of xanthine oxidase is discussed.

Adult↗
PubMed1968

Preservation of isolated heart for 72 hours.

Isolated hearts of dogs have been preserved in a viable condition for 72 hours with hypothermic perfusion (5 degrees C.) at normal atmospheric pressure. On removal and connexion to the femoral artery and vein of another dog these hearts beat strongly and without failing until removed after six hours. In mechanical function and histological appearance they were virtually identical with control hearts. The most useful criterion of viability of the quiescent myocardium during storage was the change in coronary resistance with time of perfusion.

Animals↗