RESUMEN
Urine xanthine crystals are remarkably rare but can be observed by routine urine microscopy. We report the results of a 67-year-old man with T-cell-prolymphocytic leukemia whose urine contained xanthine crystals after chemotherapy and prophylactic administration of febuxostat. Accumulation of xanthine was due to tumor lysis syndrome causing a massive release of DNA. The metabolized DNA caused an increase of xanthine, which was not readily converted to uric acid by xanthine oxidase because of febuxostat inhibition of this enzyme.
RESUMEN
BACKGROUND: Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a nuclear receptor that regulates not only adipogenesis but also immune reaction. We previously demonstrated that human eosinophils expressed functional PPARgamma, although the modulator of PPARgamma expression is less well understood. Because clinical studies have shown that the efficacy of PPARgamma agonists as insulin sensitizers is stronger in women than in men, we investigated whether sex hormones caused any changes in eosinophil PPARgamma expression levels. METHODS: First, purified human peripheral blood eosinophils were cultured with 17beta-estradiol for 24 h, followed by PPARgamma measurement using a flow cytometer. Next, eosinophil PPARgamma expression and serum estradiol were studied in 10 healthy women during the menstrual and follicular phases to identify the physiological significance of estradiol. Eosinophil PPARgamma expression was also compared in 22 men, 21 non-pregnant women, and 15 pregnant women. RESULTS: We observed that PPARgamma protein expression in eosinophils was significantly enhanced by 10(-6)M 17beta-estradiol. Although serum estradiol concentration was increased during the follicular phase, PPARgamma expression levels were not affected by the menstrual cycle. In addition, no significant differences in PPARgamma expression were observed in terms of sex and pregnancy. CONCLUSIONS: These findings suggest that estradiol potentially upregulates eosinophil PPARgamma expression in vitro, although some other mechanisms might be involved in its regulation in vivo.