Bartges J W, Osborne C A, Felice L J, Chen M, Ulrich L K
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul 55108, USA.
Am J Vet Res. 1997 Feb;58(2):118-20.
To evaluate the effects of dilution on stability of xanthine in canine urine stored at -20 C, and to evaluate the effects of storage at -20 C on stability of xanthine in canine plasma.
6 reproductively intact female Beagles, 3.9 to 4.2 years old and weighing 8.5 to 10.1 kg.
Dogs were fed a 31.4% protein (dry weight), meat-based diet for 21 days, and administered allopurinol (15 mg/kg of body weight, q 12 h) during days 14 to 21; urine and plasma samples were obtained on day 22. Urine samples were preserved undiluted or diluted, and divided into 1-ml aliquots for storage at -20 C for 1 to 12 weeks. Plasma samples were divided into 1-ml aliquots for storage at -20 C for 1 to 12 weeks. Urine and plasma xanthine concentrations were measured on day of collection (baseline) and after 1, 2, 4, 6, 9, and 12 weeks.
Dilution of urine samples did not have a significant effect on consistency of xanthine concentration measured for up to 12 weeks of storage. Although xanthine concentration did not differ significantly between undiluted and diluted urine samples, average xanthine concentration measured in diluted samples was consistently higher, compared with that in undiluted samples. Compared with baseline values, plasma xanthine concentration was significantly lower at 6, 9, and 12 weeks of storage.
Measurement of xanthine concentration is reproducible in undiluted or diluted urine samples for up to 12 weeks, although dilution may provide better results. Measurement of plasma xanthine concentration is reproducible in samples stored for up to 4 weeks.
To ensure reproducibility of measurements of xanthine concentration in urine samples collected from dogs that are affected with urate uroliths and receiving allopurinol, urine should be diluted 1:20 with deionized water. These measurements may be useful for monitoring dogs that are receiving allopurinol for dissolution or prevention of urate uroliths.
评估稀释对储存于-20℃的犬尿液中黄嘌呤稳定性的影响，并评估-20℃储存对犬血浆中黄嘌呤稳定性的影响。
6只生殖功能正常的雌性比格犬，年龄3.9至4.2岁，体重8.5至10.1千克。
给犬喂食含31.4%蛋白质（干重）的肉类饮食21天，并在第14至21天给予别嘌醇（15毫克/千克体重，每12小时一次）；在第22天采集尿液和血浆样本。尿液样本不稀释或稀释后保存，分成1毫升的等分试样在-20℃储存1至12周。血浆样本分成1毫升的等分试样在-20℃储存1至12周。在采集日（基线）以及1、2、4、6、9和12周后测量尿液和血浆中的黄嘌呤浓度。
尿液样本的稀释对储存长达12周期间所测黄嘌呤浓度的一致性没有显著影响。尽管未稀释和稀释后的尿液样本中黄嘌呤浓度没有显著差异，但与未稀释样本相比，稀释样本中所测平均黄嘌呤浓度始终较高。与基线值相比，储存6、9和12周时血浆黄嘌呤浓度显著降低。
未稀释或稀释后的尿液样本中黄嘌呤浓度的测量在长达12周内具有可重复性，尽管稀释可能会提供更好的结果。血浆黄嘌呤浓度的测量在储存长达4周的样本中具有可重复性。
为确保从患有尿酸盐尿石症并接受别嘌醇治疗的犬采集的尿液样本中黄嘌呤浓度测量的可重复性，尿液应用去离子水按1:20稀释。这些测量对于监测接受别嘌醇以溶解或预防尿酸盐尿石症的犬可能有用。
