Article

The applicability of urinary creatinine as a method of specimen normalization in the cystic fibrosis population

Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Denver, 13001 E. 17th Place, B119, Aurora, CO, 80045, USA.
Journal of cystic fibrosis: official journal of the European Cystic Fibrosis Society (Impact Factor: 3.82). 03/2010; 9(3):212-6. DOI: 10.1016/j.jcf.2010.02.004
Source: PubMed

ABSTRACT Urine specimens are commonly used in biomarker research. Urinary creatinine (UCr) is often used to adjust for urine analyte concentration. We aim to explore the applicability of UCr as a normalization method in a cystic fibrosis (CF) population during hospitalization.
Multiple spot urine samples were collected from CF patients hospitalized for a pulmonary exacerbation. Single spot specimens were obtained from asthmatics and healthy children for comparison. The assumptions and implications from the use of UCr as a normalization factor for urinary desmosine measurements were investigated.
UCr differed significantly across disease groups and decreased significantly over time in the CF population. Differing results were obtained when contrasting normalization by UCr with specific gravity.
UCr levels are not completely attributable to simply variations in urine concentration. Analysis of urinary biomarker measurements should be initiated with an understanding of the relative effects of the normalization process on the results.

Download full-text

Full-text

Available from: Theresa A Laguna, Sep 02, 2015
0 Followers
 · 
174 Views
 · 
63 Downloads
  • Source
    • "One interesting possibility is to use the level of other biomolecules in body fluids such as creatinine levels in blood and urine to normalize miRNAs. The levels of creatinine have been used to " normalize " other biomolecules in urine, and it provides an interesting possibility as a normalization basis for miRNAs in plasma and urine [70] [71]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: MicroRNAs (miRNAs) are a recently discovered class of small, non-coding RNAs that regulate protein levels post-transcriptionally. miRNAs play important regulatory roles in many cellular processes, including differentiation, neoplastic transformation, and cell replication and regeneration. Because of these regulatory roles, it is not surprising that aberrant miRNA expression has been implicated in several diseases. Recent studies have reported significant levels of miRNAs in serum and other body fluids, raising the possibility that circulating miRNAs could serve as useful clinical biomarkers. Here, we provide a brief overview of miRNA biogenesis and function, the identification and potential roles of circulating extracellular miRNAs, and the prospective uses of miRNAs as clinical biomarkers. Finally, we address several issues associated with the accurate measurement of miRNAs from biological samples.
    Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 03/2011; 717(1-2):85-90. DOI:10.1016/j.mrfmmm.2011.03.004 · 4.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: X-ray absorption near edge structure (XANES) analysis in combination with synchrotron radiation induced total reflection X-ray fluorescence (SR-TXRF) acquisition was used to determine the oxidation state of Fe in human cancer cells and simultaneously their elemental composition by applying a simple sample preparation procedure consisting of pipetting the cell suspension onto the quartz reflectors. XANES spectra of several inorganic and organic iron compounds were recorded and compared to that of different cell lines. The XANES spectra of cells, independently from the phase of cell growth and cell type were very similar to that of ferritin, the main Fe store within the cell. The spectra obtained after CoCl2 or NiCl2 treatment, which could mimic a hypoxic state of cells, did not differ noticeably from that of the ferritin standard. After 5-fluorouracil administration, which could also induce an oxidative-stress in cells, the absorption edge position was shifted toward higher energies representing a higher oxidation state of Fe. Intense treatment with antimycin A, which inhibits electron transfer in the respiratory chain, resulted in minor changes in the spectrum, resembling rather the N-donor Fe-α,α′-dipyridyl complex at the oxidation energy of Fe(III), than ferritin. The incorporation of Co and Ni in the cells was followed by SR-TXRF measurements.
    Spectrochimica Acta Part B Atomic Spectroscopy 03/2011; 66(3-4-3-4):274-279. DOI:10.1016/j.sab.2011.03.011 · 3.15 Impact Factor
  • Radiotherapy and Oncology 05/2011; 99. DOI:10.1016/S0167-8140(11)70379-6 · 4.86 Impact Factor
Show more