Nucleus pulposus notochord cells secrete connective tissue growth factor and up-regulate proteoglycan expression by intervertebral disc chondrocytes.

Objective: To identify the components of conditioned medium obtained from intervertebral disc nucleus pulposus-derived canine notochord cells, and to evaluate the capacity of such factors to affect disc-derived chondrocyte gene expression of aggrecan, versican, and hyaluronic acid synthase 2 (HAS-2) as a function of culture conditions.

Methods: Canine notochord cells obtained from nonchondrodystrophic dogs were cultured within alginate beads under conditions of serum deficiency (Dulbecco's modified Eagle's medium [DMEM]) to produce notochord cell-conditioned medium (NCCM). NCCM was evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and liquid chromatography-tandem mass spectroscopy.

Automated, rapid solid-phase proteolytic cleavage and sample preparation for proteomics.

The development of robotic sample preparation systems has allowed the throughput of protein analysis to be accelerated. However, one of the rate-limiting steps in preparing protein samples for analysis by mass spectrometry is their proteolytic cleavage. Robots have been successfully used for the in-gel tryptic digestion of proteins as well as the desalting, concentration, and loading of protein digests onto matrix-assisted laser desorption/ionization (MALDI) targets.