Abstract: Provided herein are methods of increasing lipoprotein lipase (LPL) activity, by inhibiting apolipoprotein C3 (ApoCIII), which removes the ApoCIII inhibition of LPL, and permits VLDL to be converted to LDL. Also provided are methods for treating or preventing a lipid metabolism disorder, such as type 2 diabetes by use of an ApoCIII antagonist. Also provided are screening methods to identify ApoCIII antagonists.

Abstract: Disclosed is a composition that synergistically prevents proteolysis or modification of peptides in sampled biological fluids using sulfonyl fluoride family protease inhibitors at high concentrations combined with at least one additional protease inhibitor of a different type, preferably a broad spectrum protease inhibitor, and a chelator. A preferred embodiment uses AEBSF at 10 mM, Benzamidine at 20 mM and EDTA as the chelator. The disclosed composition may be combined with other protease inhibitors to further modulate its specificity, for instance to additionally target acidic proteases. Additional protease inhibitors, reducing agents, stabilizers and buffering agents may be combined with the disclosed compositions in devices for sampling or testing biological fluids for levels of peptides of interest, or methods therefore. The disclosed devices, compositions and methods are of particular use in sampling and testing for the level of natriuretic peptides.

Abstract: Provided herein are methods of increasing lipoprotein lipase (LPL) activity, by inhibiting apolipoprotein C3 (ApoCIII), which removes the ApoCIII inhibition of LPL, and permits VLDL to be converted to LDL. Also provided are methods for treating or preventing a lipid metabolism disorder, such as type 2 diabetes by use of an ApoCIII antagonist. Also provided are screening methods to identify ApoCIII antagonists.

Abstract: Methods to assess biological enzyme activity directly in a complex clinical sample. To such a sample, e.g., plasma, an exogenous synthetic peptide substrate for an enzyme present in the sample and to be assessed is added. The sample then undergoes mass spectrometric immunoassay (MSIA) to monitor the mass spectral profile of the immuno-purified exogenous synthetic peptide substrate directly from the sample. Using the resulting profile, parameters such as enzyme activity and effect of enzyme modulators, including therapeutics administered to an individual for a condition involving the enzyme, may be determined.

Abstract: Presented herein are methods, devices and kits for the mass spectrometric immunoassay (MSIA) of proteins present in complex biological fluids or extracts. Pipettor tips containing porous solid supports that are covalently derivatized with affinity ligand and used to extract specific proteins and their variants from various biological fluids. Nonspecifically bound compounds are rinsed from the extraction devices using a series of buffer and water rinses, after which the wild type protein (and/or its variants) are eluted directly onto a target in preparation for analysis such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Mass spectrometry of the eluted sample then follows with the retained proteins identified via accurate molecular mass determination.

Abstract: Disclosed is a composition that synergistically prevents proteolysis or modification of peptides in sampled biological fluids using sulfonyl fluoride family protease inhibitors at high concentrations combined with at least one additional protease inhibitor of a different type, preferably a broad spectrum protease inhibitor, and a chelator. A preferred embodiment uses AEBSF at 10 mM, Benzamidine at 20 mM and EDTA as the chelator. The disclosed composition may be combined with other protease inhibitors to further modulate its specificity, for instance to additionally target acidic proteases. Additional protease inhibitors, reducing agents, stabilizers and buffering agents may be combined with the disclosed compositions in devices for sampling or testing biological fluids for levels of peptides of interest, or methods therefore. The disclosed devices, compositions and methods are of particular use in sampling and testing for the level of natriuretic peptides.

Abstract: Presented herein are methods, devices and kits for the mass spectrometric immunoassay (MSIA) of proteins present in complex biological fluids or extracts. Pipettor tips containing porous solid supports that are covalently derivatized with affinity ligand and used to extract specific proteins and their variants from various biological fluids. Nonspecifically bound compounds are rinsed from the extraction devices using a series of buffer and water rinses, after which the wild type protein (and/or its variants) are eluted directly onto a target in preparation for analysis such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Mass spectrometry of the eluted sample then follows with the retained proteins identified via accurate molecular mass determination.