{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,2,9]],"date-time":"2025-02-09T23:40:07Z","timestamp":1739144407517,"version":"3.37.0"},"reference-count":33,"publisher":"Cambridge University Press (CUP)","issue":"3","license":[{"start":{"date-parts":[[2009,4,6]],"date-time":"2009-04-06T00:00:00Z","timestamp":1238976000000},"content-version":"unspecified","delay-in-days":6153,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Parasitology"],"published-print":{"date-parts":[[1992,6]]},"abstract":"<jats:p>Patients infected with<jats:italic>Schistosoma mansoni<\/jats:italic>showed an abnormal response to a test dose of tryptophan, with little increase in the urinary excretion of kynurenine, hydroxykynurenine, xanthurenic and kynurenic acids,<jats:italic>N<\/jats:italic><jats:sup>1<\/jats:sup>-methyl nicotinamide, methyl pyridone carboxamide, 5-hydroxytryptamine or 5-hydroxyindoleacetic acid. In contrast to previous reports, this is different from the pattern of tryptophan metabolism seen in vitamin B<jats:sub>6<\/jats:sub>deficiency. Furthermore, the patients' plasma concentrations of pyridoxal phosphate were within the reference range, and supplementation for 5 days with 20 mg vitamin B<jats:sub>6<\/jats:sub>\/day did not affect tryptophan metabolism. Treatment with a single dose of Praziquantel resulted in a substantial restoration of normal tryptophan metabolism. In mice infected with<jats:italic>S. mansoni<\/jats:italic>there was a similar impairment of tryptophan metabolism, as shown by considerably reduced formation of<jats:sup>14<\/jats:sup>CO<jats:sub>2<\/jats:sub>after the administration of a tracer dose of [<jats:sup>14<\/jats:sup>C]tryptophan. Again, the administration of vitamin B<jats:sub>6<\/jats:sub>supplements did not correct tryptophan metabolism in the mice. Treatment with Praziquantel resulted in substantial restoration of the production of<jats:sup>14<\/jats:sup>CO<jats:sub>2<\/jats:sub>from [<jats:sup>14<\/jats:sup>C]tryptophan. There was no evidence of vitamin B<jats:sub>6<\/jats:sub>deficiency (as determined by erythrocyte aspartate aminotransferase activation coefficient) associated with infection in the mice, although there was a redistribution of pyridoxal phosphate between tissues, with a reduction in the concentration of liver, spleen and kidney, and an increase in skeletal muscle.<\/jats:p>","DOI":"10.1017\/s0031182000063691","type":"journal-article","created":{"date-parts":[[2009,6,5]],"date-time":"2009-06-05T14:24:55Z","timestamp":1244211895000},"page":"433-441","source":"Crossref","is-referenced-by-count":2,"title":["Tryptophan metabolism and vitamin B<sub>6<\/sub>nutritional status in patients with schistosomiasis mansoni and in infected mice"],"prefix":"10.1017","volume":"104","author":[{"given":"E. N. 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