酶联免疫吸附（ELISA）法测定生猪尿液中的沙丁胺醇

将标准品、样品和和酶标记物一并加入到微孔板中孵育,样品中的游离沙丁胺醇与酶标记的沙丁胺醇竞争结合酶标板微孔中固定相化的沙丁胺醇特异性抗体,通过清洗步骤洗掉未结合的酶标记沙丁胺醇,再通过酶的专一性显色剂显色,微孔显蓝色,加入反应终止液使颜色由蓝色转为黄色。在450nm处测量吸光度（OD）值,并设置标准曲线,通过标准曲线测定样品中沙丁胺醇的含量,结果显示：OD值的大小与样品中沙丁胺醇的含量成反比。     

气相色谱/质谱法测定猪尿中士的宁残留量的研究

建立了气相色谱/质谱法则定猪尿中士的宁残留量的方法.试样在碱性条件下,经甲基叔丁基醚提取,MCX固相萃取柱净化后,用GC/MS测定其中的士的宁.方法检测限和定量限分别为0.005 mg/l和0.01 mg/l;回收率在61.24%～387.76%之间,变异系数在8.43%～12.82%之间.本方法对猪尿中士的宁残留量的检测分析准确可靠.     

Urine protein determination in dogs and cats: comparison of dipstick and sulfasalicylic acid procedures

Protein levels in urine specimens from 91 dogs and 65 cats were evaluated by sulfasalicylic acid precipitation (SSA) and dipstick methods. The dipstick frequently yielded reactions for protein that were greater than the level of protein indicated by SSA (i.e., false positive reactions), although no false negative reactions for protein were noted. All urine specimens with protein levels equal to or greater than 100 mg/dl by SSA had dipstick results of 3 +. Results of this study suggest that dipstick analysis for urine protein is an adequate screening procedure for the selection of urines for quantitative analysis of protein and creatinine to assess proteinuria.     

Urinary excretion of theobromine in horses given contaminated pelleted food

A high pressure liquid chromatographic (HPLC) method for measuring the theobromine content in cocoa husks, pelleted food and horse urine is described. Starting with 2 ml of urine, concentrations of 500 ng/ml could easily be detected. When feed containing 38.4 mg of theobromine was given twice daily to horses for 21/2 days, two days were needed after the last intake before the theobromine concentrations fell below the threshold value of 2 g/ml. The time at which the peak excretion rate occurred varied from 2 to 12 h after the last administration, while the excretion rate seemed to be dependent on the urinary flow. Theobromine could not be detected in plasma after administration in this way.     

Effects of dietary crude protein and tannic acid on nitrogen excretion,urinary nitrogenous composition and urine nitrous oxide emissions in beef cattle

Two consecutive trials were carried out to study the effects of dietary crude protein (CP) and tannic acid (TA) on nitrogen (N) metabolism of beef cattle and consequently, the N₂O emissions from the urine of cattle. In Trial I, eight growing castrated cattle were used as the experimental animals. Two levels of dietary CP (110.6 and 135.7 g/kg dry matter [DM]) and two levels of TA (0 and 16.9 g/kg DM) were allocated in a replicated 2 × 2 crossover design. In Trial II, the N₂O emissions from the urine of cattle collected from Trial I were determined using the static incubation technique. An interaction between dietary CP and TA on the urinary N excretion (p < .05) was found but not on the N₂O‐N emission of cattle urine. Increasing dietary CP level from 110.6 g/kg DM to 135.7 g/kg DM increased the total N excretion (p < .001), the N retention (p < .05) and the ratio of urinary urea‐N/urinary N (p < .01), did not affect the N use efficiency (NUE; p > .05) and shifted the N excretion from faeces to urine. Increasing the dietary CP level increased the N₂O‐N emission of cattle urine. Dietary addition of TA decreased the urinary excretions of urea (p < .001) and shifted the N excretion from urine to faeces, did not affect the NUE of beef cattle (p > .10), and decreased the N₂O‐N emission of cattle urine. Pyrogallol and resorcinol of the TA metabolites were detected in urine with dietary addition of TA. Feeding beef cattle with relatively low CP level and adding TA in rations are effective approaches to mitigate the N₂O‐N emissions from cattle urine.     

Basal glucosuria in cats

Objective of this study was to demonstrate the ubiquitous presence of glucose in urine of euglycemic cats by a highly sensitive glucose assay. The local electronic database was searched for results of quantitative urine glucose measurements in cats. A total of 325 feline urine glucose measurements were identified, of which 303 (93%) had been submitted by one of the co‐authors working in a near‐by small animal practice. After the exclusion of patients with kidney disease (n = 60), hyperthyroidism (n = 15), diabetes mellitus (n = 11), multiple diseases (n = 9) or steroid treatment (n = 3), as well as serial measurements (n = 87) and outliers (n = 8), the final study population consisted of 132 cats. Urine creatinine concentration was unavailable in five patients. Whereas all but one cat had glucose concentrations above the detection limit of the assay (0.11 mmol/L, Gluco‐quant Enzyme Kit/Roche Diagnostics), no positive glucose dipstick test result (Combur 9‐Test, Roche Diagnostics) was observed. The median (range) of urinary glucose concentration and the glucose‐to‐creatinine ratio (UGCR) was 0.389 (<0.11–1.665) mmol/L and 0.0258 (0.007–0.517) respectively. The UGCR was not affected by age, gender, breed or leukocyturia, whereas cats with hematuria had slightly higher values. Data show that so‐called “basal glucosuria” is present in the majority of cats and by no means diagnostic for diabetes mellitus or renal glucosuria. This has to be considered when using bio‐analytical methods with a low limit of quantification.     

An appraisal of the in vivo role of phosphate as a modulator of urinary ammonium and titratable acid excretion in the acidotic rabbit

Previous studies have shown that the intravenous infusion of inorganic phosphate increased urinary ammonium excretion 8‐ to 10‐fold in the acidotic rabbit. This was considered to be a very important observation at the time and to be unique to the rabbit. While investigating this finding, we discovered that the formol titration procedure, used to measure urinary ammonium by this research group, is subject to interference by phosphate, casting doubt on the validity of the urinary ammonium excretion data reported by them in the literature. In order to re‐assess the importance of phosphate as a potential modulator of urinary ammonium excretion in the acidotic rabbit, renal net acid excretion studies were carried out in phosphate‐loaded acidotic animals. We observed that while urinary ammonium excretion increased significantly (p < 0.05) after 50 min of phosphate infusion, the maximum concentrations excreted were substantially less than previously reported in the literature. However, through its urinary buffering capacity, we observed that inorganic phosphate, via an experimentally induced phosphaturia, could substantially enhance titratable acid excretion. Contrary to earlier reports, we demonstrated that phosphate plays a relatively minor in vivo modulator role in enhancing renal net acid excretion through the vehicle of ammonium during acute metabolic acidosis in the hyperphosphataemic rabbit. The findings reported in this study constitute an important update on ammonia metabolism in the acidotic rabbit.     

Effect of increasing taurine and methionine supplementation on urinary taurine excretion in a model insectivore,the giant anteater (Myrmecophaga tridactyla)

The giant anteater (Mymercophaga tridactyla) is a highly specialized insectivore for which nutrient requirements are not clearly established, making diet formulation challenging for this species. Multiple clinical reports suggest anteaters have an obligate dietary taurine (TAU) requirement. Sulphur amino acid (SAA) metabolism in adult anteaters was evaluated using noninvasive methods to measure TAU synthesis potential from dietary methionine (MET) and a basal diet containing on a dry matter (DM) basis 1.7 mg TAU/kg DM and 6.9 g MET/kg DM. Urinary equilibrium times for TAU excretion were determined by feeding the basal diet with or without 1.5 g/kg DM supplemental TAU (crossover design; n = 4). Effects of supplemental dietary TAU (1.7, 2.0, 2.4, 2.7, 3.0, 3.3 g/kg DM) or MET (6.9, 9.0, 11.2 g/kg DM) on urinary TAU were evaluated (randomized block trials; n = 5 or 4 respectively). All urinary values (TAU, MET, unbound inorganic sulphate) were normalized to creatinine (CRT). Results indicate urinary TAU equilibrium in anteaters requires at least 2 weeks of feeding. Urinary ratio of TAU to CRT (TAU:CRT) increased as dietary TAU content increased from 1.7 to 3.0 g/kg DM, consistent with renal homoeostatic modulation of TAU excretion. Our data indicate that TAU needs were met by TAU in the basal diet or by de novo synthesis. Supplemental MET resulted in ~five‐ to eightfold increases in urinary TAU:CRT excretion, further supporting existence of mechanisms for TAU synthesis from dietary SAA in anteaters. Adult anteaters appear able to synthesize TAU when diets contain adequate SAA, but dietary TAU may be critical if protein intakes are low or of poor quality. This study may provide guidance on choice of domestic canids vs. felids as suitable physiologic models for improved nutrition in giant anteaters, and also outlines a noninvasive method for assessing TAU status/metabolism that may be useful across species.     

Measurement of urinary concentrations of the mycotoxins zearalenone and sterigmatocystin as biomarkers of exposure in mares

Mycotoxins may affect animal health, including reproduction. Little is known about the clinical relevance of exposure of horses to contaminated feed. This study aimed at (i) monitoring the levels of the mycotoxins zearalenone (ZEN), with its metabolites α‐ and β‐zearalenol (α‐ and β‐ZOL), and sterigmatocystin (STC) in urine samples from thoroughbred mares in Japan and (ii) relating these findings to the potential effects on reproductive efficacy of breeding mares. Sixty‐three urine samples of breeding mares from 59 breeding farms were used. Urine samples and reproductive records were collected from each mare when it was presented to the stallion station. Urinary concentrations of ZEN, α‐ and β‐ZOL, and STC were measured using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). ZEN, α‐ and β‐ZOL were measurable in the urine of all examined mares, indicating the prevalence of ZEN in equine feeds. In seven of the 63 samples, STC was also detected at levels ranging from 1.3 to 18.0 pg/mg creatinine. No significant correlation between the concentrations of mycotoxins and pregnancy status was observed. In conclusion, measurement of mycotoxins in urine samples is a useful non‐invasive method for monitoring the systemic exposure of mares to multiple mycotoxins.     

骆驼尿液对预防CCl_4诱导小鼠肝损伤的保护作用

试验旨在研究骆驼尿液对预防四氯化碳(CCl_4)诱导小鼠肝损伤的保护作用。将40只C57BL/6小鼠随机分为正常组,模型组,骆驼尿液低剂量组(170 mg/kg)、中剂量组(340 mg/kg)和高剂量组(500 mg/kg),3组骆驼尿液组灌胃相应剂量的骆驼尿液,正常组和模型组灌胃等量的生理盐水,每日灌胃1次,连续14 d;试验末期,除正常组外(橄榄油),各组小鼠腹腔注射20%CCl_4橄榄油混合溶液,建立小鼠急性肝损伤模型;12 h后摘眼球取血和采集肝脏样本,并记录肝脏重量,计算肝脏指数;测定小鼠血清相关指标,并进行肝脏组织病理切片检查。结果显示,与模型组比较,低、中、高剂量骆驼尿液组小鼠血清中谷丙转氨酶(ALT)、谷草转氨酶(AST)活性及总胆红素(TBIL)、碱性磷酸酶(ALP)、葡萄糖(GLU)含量较模型组均明显降低,白蛋白(ALB)、总蛋白(TP)含量升高,且高剂量组效果较好;而小鼠肝脏病理学切片观察显示,骆驼尿液组均有不同程度的改善,其中高剂量骆驼尿液组小鼠肝脏组织病理学损伤明显减轻,与正常组的肝脏组织形态接近。比较低、中、高3种浓度骆驼尿液处理发现,浓度越高治疗效果越好,说明骆驼尿液治疗效果具有剂量依赖性。综上所述,骆驼尿液对CCl_4诱导小鼠肝损伤具有一定的预防保护作用,且高剂量骆驼尿液组的效果较好。