Multi-site assessment of the precision and reproducibility of multiple reaction monitoring–based measurements of proteins in plasma

Verification of candidate biomarkers relies upon specific, quantitative assays optimized for selective detection of target proteins, and is increasingly viewed as a critical step in the discovery pipeline that bridges unbiased biomarker discovery to preclinical validation. Although individual laboratories have demonstrated that multiple reaction monitoring (MRM) coupled with isotope dilution mass spectrometry can quantify candidate protein biomarkers in plasma, reproducibility and transferability of these assays between laboratories have not been demonstrated. We describe a multilaboratory study to assess reproducibility, recovery, linear dynamic range and limits of detection and quantification of multiplexed, MRM-based assays, conducted by NCI-CPTAC. Using common materials and standardized protocols, we demonstrate that these assays can be highly reproducible within and across laboratories and instrument platforms, and are sensitive to low µg/ml protein concentrations in unfractionated plasma. We provide data and benchmarks against which individual laboratories can compare their performance and evaluate new technologies for biomarker verification in plasma

U.S. Atomic Energy Commission Report LA-1182

Formulas, tables, graphs reviewing the multiple scattering theory of E. J. Williams

Charged-particle elastic cross sections

Modern treatments of energy loss in plasmas through elastic scattering of energetic ions require complete knowledge of charged-particle elastic cross sections. R-matrix theory provides an explicit separation of nuclear and Coulomb effects in these cross sections, and gives reasonable extrapolations to small angles and low energies, where data may be scarce. We outline the calculation of charged-particle elastic cross sections from R-matrix parameters, and given examples for d-T, d-..cap alpha.., and t-..cap alpha.. scattering, obtained from comprehensive analyses of reactions in the /sup 5/He, /sup 6/Li, and /sup 7/Li compound systems. Expansion coefficients for an exact polynomial representation for the difference of the scattering and Rutherford cross sections (sigma/sub NI/) are given for d-T scattering. Integral quantities involving sigma/sub NI/ calculated from the present cross sections disagree substantially in some cases near resonances with a recent Livermore evaluation