Choosing to view morbid information involves reward circuitry.

People often seek out stories, videos or images that detail death, violence or harm. Considering the ubiquity of this behavior, it is surprising that we know very little about the neural circuits involved in choosing negative information. Using fMRI, the present study shows that choosing intensely negative stimuli engages similar brain regions as those that support extrinsic incentives and "regular" curiosity.

Effect of collagen turnover and matrix metalloproteinase activity on healing of venous leg ulcers.

Background: The presence of fibrous tissue in poorly healing venous leg ulcers suggests abnormal collagen metabolism. The aim was to determine whether there were differences in collagen turnover and matrix metalloproteinase (MMP) activity between ulcers that healed, those that did not heal and normal skin.

Methods: Biopsies were taken from the ulcers of 12 patients whose venous ulcers went on to heal and 15 patients whose ulcers failed to heal despite 12 months of compression bandaging.

Increased collagen degradation around loosened total hip replacement implants.

Objective: To assess collagen degradation and its relationship to some of the key collagenolytic proteinases in the aggressive synovial membrane-like interface tissue around aseptically loosened hip replacement implants.

Methods: The medical indication for the primary total hip replacement was osteoarthritis in all study patients. Samples from the study patients were compared with control synovial membranes obtained from trauma (hip fracture) patients.

MMP protein and activity levels in synovial fluid from patients with joint injury, inflammatory arthritis, and osteoarthritis.

Objective: To determine protein and activity levels of matrix metalloproteinases 1 and 3 (MMP-1 and MMP-3) in synovial fluid of patients with knee joint injury, primary osteoarthritis, and acute pyrophosphate arthritis (pseudogout).

Methods: Measurements were done on knee synovial fluid obtained in a cross sectional study of cases of injury (n = 283), osteoarthritis (n = 105), and pseudogout (n = 65), and in healthy controls (n = 35). Activity of MMP-1 and MMP-3 in alpha(2) macroglobulin complexes was measured using specific low molecular weight fluorogenic substrates.

MMP profile in paired serum and synovial fluid samples of patients with rheumatoid arthritis.

Objective: To analyse matrix metalloproteinases (MMPs) and tissue inhibitor-1 of MMPs (TIMP-1) levels in the systemic circulation and synovial fluid (SF) of patients with RA and to compare these levels with inflammatory and collagen degradation markers.

Methods: ProMMP-1, -2, -3, -8, -9, TIMP-1, levels of MMP/alpha(2)-macroglobulin complexes, and collagen degradation products were measured by sandwich ELISA, activity assays, and HPLC in paired SF and serum samples from 15 patients with RA and 13 with OA.

Results: MMPs were higher in SF of patients with RA than in OA or controls.