Summary of Study ST000092
This data is available at the NIH Common Fund's National Metabolomics Data Repository (NMDR) website, the Metabolomics Workbench, https://www.metabolomicsworkbench.org, where it has been assigned Project ID PR000084. The data can be accessed directly via it's Project DOI: 10.21228/M8PK5V This work is supported by NIH grant, U2C- DK119886.
See: https://www.metabolomicsworkbench.org/about/howtocite.php
| Study ID | ST000092 |
| Study Title | A statistical analysis of the effects of urease pre-treatment on the measurement of the urinary metabolome by gas chromatographymass spectrometry |
| Study Type | Analytical Comparison |
| Study Summary | Urease pre-treatment of urine has been utilized since the early 1960s to remove high levels of urea from samples prior to further processing and analysis by gas chromatographymass spectrometry (GCMS). Aside from the obvious depletion or elimination of urea, the effect, if any, of urease pre-treatment on the urinary metabolome has not been studied in detail. Here, we report the results of three separate but related experiments that were designed to assess possible indirect effects of urease pre-treatment on the urinary metabolome as measured by GCMS. In total, 235 GCMS analyses were performed and over 106 identified and 200 unidentified metabolites were quantified across the three experiments. The results showed that data from urease pre-treated samples (1) had the same or lower coefficients of variance among reproducibly detected metabolites, (2) more accurately reflected quantitative differences and the expected ratios among different urine volumes, and (3) increased the number of metabolite identifications. Overall, we observed no negative consequences of urease pre-treatment. In contrast, urease pre-treatment enhanced the ability to distinguish between volume-based and biological sample types compared to no treatment. Taken together, these results show that urease pre-treatment of urine offers multiple beneficial effects that outweigh any artifacts that may be introduced to the data in urinary metabolomics analyses. |
| Institute | Pacific Northwest National Laboratory |
| Department | Biological Separation and Mass Spectrometry |
| Last Name | Metz |
| First Name | Thomas |
| thomas.metz@pnnl.gov | |
| Submit Date | 2014-06-25 |
| Num Groups | 6 |
| Total Subjects | 235 |
| Raw Data Available | Yes |
| Raw Data File Type(s) | cdf |
| Uploaded File Size | 3.0 G |
| Analysis Type Detail | GC-MS |
| Release Date | 2014-08-07 |
| Release Version | 1 |
Select appropriate tab below to view additional metadata details:
Treatment:
| Treatment ID: | TR000112 |
| Treatment Summary: | Varying Volume with Urease / Male vs. Female with Urease / Constant Volume with Urease / Constant Volume with 100 µL Water |
| Treatment Protocol Comments: | To evaluate whether the effects of urease pre-treatment of urine varied with the volume of urine prepared, we compared the urine metabolite profiles from pooled urine after pre-treatment with urease (UT) and after no treatment (NT) using various volumes of urine. For this, several volumes (5, 10, 25, 50, and 100 µL) of the pooled urine sample were incubated (n = 3, each) with 100 µL of a 1 mg/mL solution of urease or were not subjected to any treatment. / Finally, to evaluate whether any artifacts introduced by urease pre-treatment on the urinary metabolome interfered with the ability to distinguish between comparative samples, we compared the metabolite profiles from individual male and female urine samples after pre-treatment with urease or after no treatment (previous metabolomics studies of male and female urines (Pasikanti et al., 2008; Slupsky et al., 2007; Saude et al., 2007; Psihogios et al., 2008) have reported differences in metabolite levels). For this, 50 µL aliquots of individual male and female urine samples (n = 20, each) were blocked, randomized, and then incubated with 50 µL of a 1 mg/mL solution of urease (UT) or were not subjected to any treatment (NT), each as described above. / To initially evaluate the effects of urease pre-treatment on the urinary metabolome, we compared the urine metabolite profiles from pooled urine after pre-treatment with urease, water, or no treatment at all. For this, 100 uL aliquots of the pooled urine sample were incubated (n = 5, each) with 100 uL of a 1 mg/mL solution of urease (Sigma-Aldrich catalog number U4002) prepared in water (urease-treated; UT) or an equal volume of water alone (water-treated; WT) for 30 min at 37 C with mild shaking (500 rpm). Identical aliquots (n = 5) were not subjected to any treatment (no treatment; NT) and allowed to sit at room temperature for 30 min. / To initially evaluate the effects of urease pre-treatment on the urinary metabolome, we compared the urine metabolite profiles from pooled urine after pre-treatment with urease, water, or no treatment at all. For this, 100 uL aliquots of the pooled urine sample were incubated (n = 5, each) with 100 uL of a 1 mg/mL solution of urease (Sigma-Aldrich catalog number U4002) prepared in water (urease-treated; UT) or an equal volume of water alone (water-treated; WT) for 30 min at 37 C with mild shaking (500 rpm). Identical aliquots (n = 5) were not subjected to any treatment (no treatment; NT) and allowed to sit at room temperature for 30 min. |
| Treatment: | Abiotic |
| Treatment Compound: | Urease / Urease / Urease / Water |
| Treatment Dose: | 1 mg/ml / 1 mg/ml / 1 mg/ml / -- |
| Treatment Dosevolume: | 100 µL / 50 µL / 100 µL / 100 µL |
| Human Fasting: | Overnight Fast |
