title: Measurement of plasma-derived substance P: biological, methodological, and statistical considerations.
abstract: The undecapeptide substance P (SP) is a member of the tachykinin family of neurotransmitters, which has a pivotal role in the regulation of inflammatory and immune responses. One of the major barriers to the study of the in vivo role of SP in a number of immune disorders is the accurate measurement of SP in fluids. This is reflected in the variability of reported SP levels in serum and plasma of humans in both healthy and diseased states. This study was initiated in order to identify sources of variability by the comparative evaluation of the influences of sample preparation and analytical detection methods on the measurement of SP in plasma. The results indicate that sample preparation (peptide extraction versus no extraction) and the choice of analytical method for SP quantitation may yield significantly different values and may contribute to the variability in SP values reported in the literature. These results further emphasize the need for careful consideration in the selection of methods for SP quantitation, as well as caution in the interpretation and comparison of data reported in the literature.
authors.affiliation: Division of Allergy and Immunology, Joseph Stokes Jr. Research Institute, The Children's Hospital of Philadelphia, 34th and Civic Center Blvd., Philadelphia, PA 19104, USA. campbelld@email.chop.edu
authors.forename: Donald E
authors.initials: DE
authors.lastname: Campbell
authors.forename: Nancy
authors.initials: N
authors.lastname: Raftery
authors.forename: Richard
authors.initials: R
authors.lastname: Tustin
authors.forename: Nancy B
authors.initials: NB
authors.lastname: Tustin
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Desilvio
authors.forename: Avital
authors.initials: A
authors.lastname: Cnaan
authors.forename: Pyone Pyone
authors.initials: PP
authors.lastname: Aye
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Lackner
authors.forename: Steven D
authors.initials: SD
authors.lastname: Douglas
mesh_terms: D000818:Animals; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods* / Q000706:statistics & numerical data*; D008253:Macaca mulatta; D013373:Substance P / Q000097:blood* / Q000502:physiology
chemical_list: D013373:Substance P