Extracellular matrix inhibits structural and functional plasticity of dendritic spines in the adult visual cortex.

Brain cells are immersed in a complex structure forming the extracellular matrix. The composition of the matrix gradually matures during postnatal development, as the brain circuitry reaches its adult form. The fully developed extracellular environment stabilizes neuronal connectivity and decreases cortical plasticity as highlighted by the demonstration that treatments degrading the matrix are able to restore synaptic plasticity in the adult brain. The mechanisms through which the matrix inhibits cortical plasticity are not fully clarified. Here we show that a prominent component of the matrix, chondroitin sulfate proteoglycans (CSPGs), restrains morphological changes of dendritic spines in the visual cortex of adult mice. By means of in vivo and in vitro two-photon imaging and electrophysiology, we find that after enzymatic digestion of CSPGs, cortical spines become more motile and express a larger degree of structural and functional plasticity.

Evaluating alternative service contracts for medical equipment.

Managing medical equipments is a formidable task that has to be pursued maximizing the benefits within a highly regulated and cost-constrained environment. Clinical engineers are uniquely equipped to determine which policies are the most efficacious and cost effective for a health care institution to ensure that medical devices meet appropriate standards of safety, quality and performance. Part of this support is a strategy for preventive and corrective maintenance. This paper describes an alternative scheme of OEM (Original Equipment Manufacturer) service contract for medical equipment that combines manufacturers' technical support and in-house maintenance. An efficient and efficacious organization can reduce the high cost of medical equipment maintenance while raising reliability and quality. Methodology and results are discussed.