Sample handling for mass spectrometric proteomic investigations of human urine

Because of its non-invasive sample collection method, human urine is an attractive biological material both for discovering biomarkers and for use in future screening trials for different diseases. Before urine can be used for these applications, standardized protocols for sample handling that optimize protein stability are required. In this explorative study, we examine the influence of different urine collection methods, storage temperatures, storage times, and repetitive freeze-thaw procedures on the protein profiles obtained by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Prospectively collected urine samples from 11 women were collected as either morning or midday specimens. The effects of storage temperature, time to freezing, and freeze-thaw cycles were assessed by calculating the number, intensity, and reproducibility of peaks visualized by SELDI-TOF-MS. On the CM10 array, 122 peaks were detected and 28 peaks were found to be significantly different between urine types, storage temperature and time to freezing. On the IMAC-Cu array, 65 peaks were detected and 1 peak was found to be significantly different according to time to freezing. No significant differences were demonstrated for freeze-thaw cycles. Optimal handling and storage conditions are necessary in clinical urine proteomic investigations. Collection of urine with a single and consistently performed protocol is needed to reduce analytical bias. Collecting only one urine type, which is stored for a limited period at 4°C until freezing at -80°C prior to analysis will provide the most stable profiles.     

Discovery and validation of urinary biomarkers for prostate cancer

Only 30% of patients with elevated serum prostate specific antigen (PSA) levels who undergo prostate biopsy are diagnosed with prostate cancer (PCa). Novel methods are needed to reduce the number of unnecessary biopsies. We report on the identification and validation of a panel of 12 novel biomarkers for prostate cancer (PCaP), using CE coupled MS. The biomarkers could be defined by comparing first void urine of 51 men with PCa and 35 with negative prostate biopsy. In contrast, midstream urine samples did not allow the identification of discriminatory molecules, suggesting that prostatic fluids may be the source of the defined biomarkers. Consequently, first void urine samples were tested for sufficient amounts of prostatic fluid, using a prostatic fluid indicative panel (“informative” polypeptide panel; IPP). A combination of IPP and PCaP to predict positive prostate biopsy was evaluated in a blinded prospective study. Two hundred thirteen of 264 samples matched the IPP criterion. PCa was detected with 89% sensitivity, 51% specificity. Including age and percent free PSA to the proteomic signatures resulted in 91% sensitivity, 69% specificity.     

The variability in tissue proteomics

Variability is one of the most critical issues of concern in clinical proteomics. In this issue of Proteomics Clinical Applications, Yoshida et al. [Proteomics Clin. Appl. 2012, 6, 412-417] describe the effects of blood and number of washes on the human glomerular proteome isolated from the kidney by laser microdissection. The blood-derived proteins occupied almost 50% of all the identified proteins in the unwashed samples, whereas varying the number of washes (from 1-5) with PBS yielded only 43-80% of the proteins identified in each sample that were common in all samples. This urges caution to all proteomists to carefully consider sample preservation and preparation for tissue proteome analysis.     

人体尿液中黄蝶呤水平检测及其意义

目的：探讨尿黄蝶吟与癌症的关系及临床意义．方法：采用荧光光度结合纸层析法测定了29例健康人、11例普通病人、23例癌症病人的尿黄蝶呤水平。结果：癌症患者尿黄蝶呤含量明显高于健康人。普通病人与健康人的尿黄蝶呤水平相差不大,健康组中老年人的尿黄蝶呤含量高于年轻人。淋巴瘤、肝癌、胃癌患者尿黄蝶呤水平较高．结论：尿黄蝶呤的含量与人的年龄大小有关。黄蝶呤有可能作为淋巴瘤、肝癌和胃癌等癌症的肿瘤标志物。     

Nitrous oxide emissions from grazing cattle urine patches: Bridging the gap between measurement and stakeholder requirements

Nitrous oxide (N₂O) is a potent greenhouse gas and a precursor to compounds which deplete stratospheric ozone. Agricultural soils are the principal anthropogenic N₂O source, which includes urine patches of cattle fed by grazing pasture. While such N₂O emissions can be measured, involved time and space scales are usually only minutes and metres, respectively. Nevertheless, climate change stakeholders need large-scale national emissions over time to construct annual N₂O emissions inventories for international treaty compliance requirements. We have developed a mathematical model to bridge the gap between measurement and stakeholder requirements for N₂O emissions from grazing cattle urine patches.Our methodology begins with the emissions from a patch. Convolution integrals are then used to spatially and temporally scale the emissions from discrete grazing events to paddock, farm and region levels across the year. The model developed shows how the emissions are smoothed out with scaling and the implications from the scaling.     

新型尿液分析仪的研制

本文介绍以80C552为控制核心,运用先进的CCD图像处理技术研制的新型尿液分析仪。阐述尿液分析仪的基本原理,并对系统的组成和各部分的作用作详细介绍,实验证明此仪器测量速度和测量精度都有很大提高。     

气相色谱和质谱法测量尿中硫代二甘醇含量

硫磺芥子气体对人体的危害极大 ,本文阐述了世界上最先进、最精密的测试方法气相色谱和质谱连测法测出人体尿样中硫代二甘醇的含量 ,最低限浓度为 5 .0mg/ml推算出痕量硫磺芥子的泄漏量。     

Ammonium recovery and energy production from urine by a microbial fuel cell

Nitrogen recovery through NH₃ stripping is energy intensive and requires large amounts of chemicals. Therefore, a microbial fuel cell was developed to simultaneously produce energy and recover ammonium. The applied microbial fuel cell used a gas diffusion cathode. The ammonium transport to the cathode occurred due to migration of ammonium and diffusion of ammonia. In the cathode chamber ionic ammonium was converted to volatile ammonia due to the high pH. Ammonia was recovered from the liquid-gas boundary via volatilization and subsequent absorption into an acid solution. An ammonium recovery rate of 3.29 g_N d⁻¹ m⁻² (vs. membrane surface area) was achieved at a current density of 0.50 A m⁻² (vs. membrane surface area). The energy balance showed a surplus of energy 3.46 kJ g_N⁻¹, which means more energy was produced than needed for the ammonium recovery. Hence, ammonium recovery and simultaneous energy production from urine was proven possible by this novel approach.     

图像处理技术在尿液检测中的应用

尿检也叫尿液分析,是临床应用中非常重要也使用非常广泛的一种方法,传统的基于光电法颜色识别分辨率低,误差大,本文提出一种基于图像处理的尿液检测方案,用数字图像处理的方法进行颜色识别。通过比较分析选取YUV色彩空间为颜色空间,在对尿液试纸图像预处理、边缘检测及分割的基础上对试纸颜色块进行了颜色识别,通过MATLAB仿真实现了较好的颜色识别效果。     

Urinary BTEX, MTBE and naphthalene as biomarkers to gain environmental exposure profiles of the general population

The aim of this work was to evaluate urinary benzene, toluene, ethylbenzene, m+p-xylene, o-xylene (BTEX), methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and naphthalene (NAP) as biomarkers of exposure to environmental pollutants. Personal air and urine samples from 108 subjects belonging to the Italian general population were compared. Urinary profiles were obtained by headspace gas chromatography-mass spectrometry. BTEX, MTBE, ETBE and NAP median airborne exposures during a 5-h sampling were 4.0, 25.3, 3.8, 9.3, 3.4, 3.4, < 0.8, and 3.4 µg/m³, respectively. Meanwhile, median urinary levels, as geometric means of three determinations were: 122, 397, 74, 127, 43, 49, < 15, and 46 ng/L, respectively. Urinary benzene and toluene concentrations were 4.6- and 1.2-fold higher in smokers than in non-smokers. For most chemicals, significant positive correlations between airborne exposure (log-transformed) and the corresponding biological marker (log-transformed) were found, with Pearson's r values for correlation, ranging from 0.228 to 0.396. Multiple linear regression analysis showed that the urinary level of these chemicals was influenced by personal airborne exposure, urinary creatinine, and urinary cotinine, with R² 0.733 for benzene. Urinary chemicals are useful biomarkers of environmental exposure. Given the ease of rapidly obtaining urine samples, they represent a non-invasive alternative to blood chemical analysis. The possibility of obtaining urinary exposure profiles makes this method an appealing tool for environmental epidemiology.