{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,1]],"date-time":"2026-08-01T01:23:46Z","timestamp":1785547426650,"version":"3.56.0"},"reference-count":0,"publisher":"American Society for Microbiology","issue":"6","license":[{"start":{"date-parts":[[1978,12,1]],"date-time":"1978-12-01T00:00:00Z","timestamp":281318400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Antimicrob Agents Chemother"],"published-print":{"date-parts":[[1978,12]]},"abstract":"<jats:p>A gas chromatographic-mass spectrometric method for detecting 5-fluorouracil (5-FU) in serum at concentrations as low as 10 ng\/ml was used to determine to what extent 5-FU was present in the serum of patients taking oral 5-fluorocytosine (5-FC). Preliminary studies in two patients and two healthy volunteers given an initial 2-g oral dose of 5-FC demonstrated sustained serum 5-FU levels (&gt;100 ng\/ml) during the 5 h after ingestion of drug. Pharmaceutical preparations of 5-FC used in these studies were shown to be insignificantly contaminated with 5-FU (&lt;0.03%), suggesting in vivo conversion of 5-FC to 5-FU had occurred. Serum samples from seven patients with cryptococcal meningitis treated with amphotericin B and 5-FC were examined for 5-FU. Five of these patients had experienced hematological or other toxicity attributed to 5-FC at some time during the course of therapy. Of 41 serum samples, 20 were observed to have 5-FU levels greater than 1,000 ng\/ml in the range observed with cancer chemotherapeutic doses of 5-FU known to be associated with hematological toxicity. It is concluded that conversion of 5-FC to 5-FU occurs in humans and furthermore that 5-FU may account for some of the toxicity observed with 5-FC.<\/jats:p>","DOI":"10.1128\/aac.14.6.903","type":"journal-article","created":{"date-parts":[[2012,6,27]],"date-time":"2012-06-27T23:57:02Z","timestamp":1340841422000},"page":"903-908","update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":101,"title":["Evidence for Conversion of 5-Fluorocytosine to 5-Fluorouracil in Humans: Possible Factor in 5-Fluorocytosine Clinical Toxicity"],"prefix":"10.1128","volume":"14","author":[{"given":"Robert B.","family":"Diasio","sequence":"first","affiliation":[{"name":"Department of Medicine, Medical College of Virginia\u2013Virginia Commonwealth University, Richmond, Virginia 23298"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Duane E.","family":"Lakings","sequence":"additional","affiliation":[{"name":"Laboratory of Chemical Pharmacology, National Cancer Institute, Bethesda, Maryland 20014"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John E.","family":"Bennett","sequence":"additional","affiliation":[{"name":"Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20014"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","container-title":["Antimicrobial Agents and Chemotherapy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/AAC.14.6.903","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/AAC.14.6.903","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,2,21]],"date-time":"2022-02-21T23:15:21Z","timestamp":1645485321000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/AAC.14.6.903"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1978,12]]},"references-count":0,"journal-issue":{"issue":"6","published-print":{"date-parts":[[1978,12]]}},"alternative-id":["10.1128\/AAC.14.6.903"],"URL":"https:\/\/doi.org\/10.1128\/aac.14.6.903","relation":{},"ISSN":["0066-4804","1098-6596"],"issn-type":[{"value":"0066-4804","type":"print"},{"value":"1098-6596","type":"electronic"}],"subject":[],"published":{"date-parts":[[1978,12]]},"assertion":[{"value":"1978-12-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}