Candida infections in patients with acute leukemia: ineffectiveness of nystatin prophylaxis and relationship between oropharyngeal and systemic candidiasis

Ninety-three hospitalizations of 70 patients, who underwent induction chemotherapy for acute leukemia to determine the effectiveness of oral nystatin in preventing oropharyngeal and systemic candidiasis were reviewed. Sixty-two percent of patients who received prophylactic nystatin and 58% of patients who did not receive nystatin developed oropharyngeal candidiasis; 11% of patients who received prophylaxis and 21% of those who did not receive prophylaxis developed systemic candidiasis. The use of oral nystatin did not significantly diminish the risk of developing either type of Candida infection. Oropharyngeal candidiasis occurred more commonly in patients who had severe and prolonged leukopenia, had received more parenteral antibiotics, and had developed chemotherapy-induced mucositis. Systemic candidiasis developed almost exclusively in patients who had prior oropharyngeal candidiasis. Guidelines for the empiric use of amphotericin B in these patients are provided.     

A transformation anomaly in a Cu–Zn–Al alloy

A comparison is described of the structures of an M9R Cu–Zn–Al alloy as quenched directly into the martensitic state, and as stabilized, with the structure of the material after up-quenching into the β₁ state after which treatment the martensitic memory transformation occurs thermoelastically. Preliminary results on the increased tendency for the stabilized alloy to form f.c.c. stacking sequence regions are given and discussed.     

The potential for lower extremity revascularization without contrast arteriography: experience with magnetic resonance angiography

PURPOSE: We report an initial experience with 24 patients studied between March 1990 and April 1992 with magnetic resonance angiography (MRA) for lower extremity occlusive disease. METHODS: All patients underwent vascular intervention with either balloon angioplasty or bypass grafting, and in six patients this intervention was based on MRA findings alone. Eighteen patients were studied with both MRA and contrast arteriography, and there was observed agreement between the two studies in 98% of all arterial segments examined. RESULTS: Agreement between MRA and contrast arteriography was uniform for arterial segments below the inguinal ligament. Intraoperative findings and favorable early results of seven bypass grafts performed in six patients after MRA alone suggested this was a valid approach for patients at prohibitive risk of complications from contrast arteriography. CONCLUSIONS: Magnetic resonance angiography is accurate in demonstrating relevant anatomy in peripheral arterial occlusive disease and in selected patients may eliminate the need for contrast arteriography before lower extremity revascularization.     

Mutagenicity of nitric oxide is not caused by deamination of cytosine or 5-methylcytosine in double-stranded DNA

Several human tumors of diverse histological origin have a high incidence of C:G to T:A transition mutations at methylated CpG sites in tumor suppressor genes. We used a sensitive genetic assay to examine the ability of nitric oxide (NO), a physiological intra- and intercellular messenger molecule, to promote these transitions by deaminating cytosine (C) or methylcytosine (5mC) in double-stranded DNA. Exposure of a test double-stranded plasmid containing C or 5mC at the target site to NO in phosphate-buffered solution at pH 7.4 followed by transformation into Escherichia coli ung- strain to avoid repair of U did not result in a significant increase in reversion frequency. In addition, exposure of E. coli transformed with the target plasmid to an NO-releasing spermine-NO complex during log-phase growth did not result in larger numbers of revertants, whereas Salmonella typhimurium strain TA1535 showed a dose-responsive increase in reversion frequency when treated in the same way. We conclude that genotoxicity of NO is not caused by deamination of C or 5mC to U or T, respectively, in double-stranded DNA. This is supported by the finding that extracts of TA1535 contained high uracil-DNA glycosylase activity, suggesting that the difference in mutagenesis between the strains is not due to a lack of uracil repair. Therefore, mutational hot-spots seen in human tumor tissues at CpG sites are probably not due to the action of NO at 5mC.