Leukotrienes, but not angiotensin II, are involved in the renal effects elicited by the prolonged cyclooxygenase-2 inhibition when sodium intake is low.

It is known that cyclooxygenase-2 (COX-2) inhibition elicits significant renal hemodynamics alterations when sodium intake is low. However, the mechanisms involved in these renal changes are not well known. Our objective was to evaluate the role of angiotensin II and 5-lipooxygenase-derived metabolites in the renal effects induced by prolonged COX-2 inhibition when sodium intake is low.

Characterization of nitrotyrosine as a biomarker for arthritis and joint injury.

Objectives: To characterize the utility of nitrotyrosine (NT) as a biomarker for arthritis and joint injury.

Design: Synovial fluid, plasma, and urine from patients diagnosed with osteoarthritis (OA), rheumatoid arthritis (RA), anterior cruciate ligament (ACL) injury, meniscus injury and pseudogout, and knee-healthy volunteers were analyzed for concentrations of NT, nitrate and nitrite (NO(x)), matrix metalloproteinase (MMP)-3, MMP-1, MMP-9, more than 40 chemokines and cytokines.

Results: In OA, plasma and synovial fluid NT were increased versus healthy volunteers.

Online immunoaffinity LC/MS/MS. A general method to increase sensitivity and specificity: How do you do it and what do you need?

There is an increased emphasis on hyphenated techniques such as immunoaffinity LC/MS/MS (IA-LC/MS/MS) or IA-LC/MRM. These techniques offer competitive advantages with respect to sensitivity and selectivity over traditional LC/MS and are complementary to ligand binding assays (LBA) or ELISA's. However, these techniques are not entirely straightforward and there are several tips and tricks to routine sample analysis.

Discovery of an Oral Potent Selective Inhibitor of Hematopoietic Prostaglandin D Synthase (HPGDS).

Hematopoietic prostaglandin D synthase (HPGDS) is primarly expressed in mast cells, antigen-presenting cells, and Th-2 cells. HPGDS converts PGH2 into PGD2, a mediator thought to play a pivotal role in airway allergy and inflammatory processes. In this letter, we report the discovery of an orally potent and selective inhibitor of HPGDS that reduces the antigen-induced response in allergic sheep.

ADAM-8 isolated from human osteoarthritic chondrocytes cleaves fibronectin at Ala(271).

Objective: Fibronectin fragments are thought to play a critical role in the initiation and progression of cartilage degradation in arthritis. In a recent study, fibronectin neoepitopes resulting from cleavage of intact fibronectin at the Ala(271)/Val(272) scissile bond, generating an approximately 30-kd fragment with the new C-terminus VRAA(271) and an approximately 50-85-kd fragment with the new N-terminus (272)VYQP, were identified in osteoarthritis (OA) cartilage. The present study was undertaken to isolate the enzymes responsible for this cleavage from human OA chondrocytes.