INTENDED USE & DESCRIPTION
For use as quantitative controls for the determination of cytokine concentrations in biological fluids. Concentrations have been assigned using R&D Systems’ Quantikine® kits. Controls are prepared in diluted porcine serum with preservatives. They contain recombinant human cytokines at low, medium and high concentrations. Controls are supplied lyophilized.
STORAGE & STABILITY
Unreconstituted Controls should be stored at 2-8 °C and are stable for at least 6 months from date of receipt. Depending on the analyte of interest, reconstituted controls may be stable when stored at
REAGENT PREPARATION
Reconstitute each vial with the volume of deionized or distilled water indicated on the product datasheet.
PROCEDURE & EXPECTED VALUES
Controls should be assayed in the same manner as unknown specimens.
The acceptable ranges for the analytes in these controls are printed on the product datasheet. Due to possible variations in techniques and methodologies, it is recommended that each laboratory determine its own target range. Laboratories using other test systems should establish their own acceptable ranges as these assays may produce different values.
TECHNICAL HINTS & LIMITATIONS OF THE PROCEDURE
• The ranges were determined using R&D Systems’ Quantikine kits. If expected values are not obtained, verify that the lot numbers on the vials correspond with the lot numbers listed above and the correct volume of deionized or distilled water was used for reconstitution of the controls.
• The results obtained with these controls depend upon several factors associated with methods and instrumentation. Test systems other than those supplied by R&D Systems may result in values that differ from those printed on this product datasheet.
SOST, also known as Sclerostin, is a Cerberus/DAN family BMP antagonist and is an important regulator of bone homeostasis. Inactivating mutations in the SOST gene can cause sclerosteosis and van Buchem disease. SOST is expressed by terminally differentiated cells embedded in mineralized matrix including osteocytes, hypertrophic and prehypertrophic chondrocytes, and tooth cementocytes. Its expression is induced by BMP-2, -4, and -6 and is inhibited by parathyroid hormone (PTH). Its downregulation in osteocytes by physical loading of bone contributes to the mechanical sensor function of osteocytes and the subsequent increase in bone growth. SOST binds to BMP-2, -4, -5, -6, and -7 and inhibits the osteogenic differentiation induced by these BMPs. It inhibits canonical Wnt signaling by binding to LRP-5 and LRP-6 and inhibiting their association with Frizzled receptors. SOST reduces the proliferation of mesenchymal stem cells (MSC) and induces MSC apoptosis. Circulating levels of SOST are elevated in pathologies with bone involvement including low bone mineral density, Paget’s disease, multiple myeloma, and prostate cancer with bone metastases. It is also elevated in advanced chronic kidney disease, alcoholic liver disease, type 2 diabetes, and patients with increased abdominal and gynoid fat.
