Assessment of immunoprecipitation with subsequent immunoassays for the blood-based diagnosis of Alzheimer's disease.

The Aβ42/40 ratio and the concentration of phosphorylated Tau181 in blood plasma represent attractive biomarkers for Alzheimer's disease. As a means for reducing potential matrix effects, which may interfere with plasma immunoassays, we have previously developed a pre-analytical sample workup by semi-automated immunoprecipitation. Here we test the compatibility of pre-analytical immunoprecipitations with automated Aβ1-40, Aβ1-42 and phosphorylated Tau181 immunoassays on the Lumipulse platform and compare the diagnostic performance of the respective immunoprecipitation immunoassay approaches with direct plasma measurements.

Diagnostic performance of automated plasma amyloid-β assays combined with pre-analytical immunoprecipitation.

Background: Measurements of the amyloid-β (Aβ) 42/40 ratio in blood plasma may support the early diagnosis of Alzheimer's disease and aid in the selection of suitable participants in clinical trials. Here, we compared the diagnostic performance of fully automated prototype plasma Aβ42/40 assays with and without pre-analytical sample workup by immunoprecipitation.

Methods: A pre-selected clinical sample comprising 42 subjects with normal and 38 subjects with low cerebrospinal fluid (CSF) Aβ42/40 ratios was studied.

Development and Technical Validation of an Immunoassay for the Detection of APP (Aβ) in Biological Samples.

The ratio of amyloid precursor protein (APP) (Aβ)/Aβ in blood plasma was reported to represent a novel Alzheimer's disease biomarker. Here, we describe the characterization of two antibodies against the N-terminus of Aβ and the development and "fit-for-purpose" technical validation of a sandwich immunoassay for the measurement of Aβ. Antibody selectivity was assessed by capillary isoelectric focusing immunoassay, Western blot analysis, and immunohistochemistry.

Mass spectometry-based protein patterns in the diagnosis of sepsis/systemic inflammatory response syndrome.

Early differential diagnosis of systemic inflammatory reactions in critically ill patients is essential for timely implementation of lifesaving therapies. Despite many efforts made, reliable biomarkers to discriminate between infectious and noninfectious causes of systemic inflammatory response syndrome (SIRS) are currently not available. Recent advances in mass spectrometry-based methods have raised hopes that identification of spectral patterns from serum/plasma samples can be instrumental in this context.

Identification of proteins from colorectal cancer tissue by two-dimensional gel electrophoresis and SELDI mass spectrometry.

We investigated protein profiles obtained from colorectal tumor tissue and adjacent normal mucosa to identify tumor specific changes. Protein extracts of biopsis were separated by two-dimensional gel electrophoresis and >40 low-molecular mass proteins were identified by peptide fingerprinting using surface-enhanced laser desoption/ionization mass spectrometry (SELDI-MS). Among these, PACAP protein, hnrnp A1, flavin reductase, calgizzarin, NDK B (NM23-H2), cyclophilin A and smooth muscle protein 22-alpha showed significantly differential abundancy in the analyzed specimens.