Interleukin-1α, -6, and -8 decrease Cdc42 activity resulting in loss of articular chondrocyte phenotype.

Small GTPase proteins mediate changes in cellular morphology and other cellular functions. The aim of this study was to examine signaling of the small GTPase Cdc42 by stimulating chondrocytes grown in monolayer with long- (96 h) or short- (2 and 30 min) term exposure to interleukin-1α (IL-1α), IL-6, or IL-8. Quantitative PCR was used to determine changes in collagen type IIB (COL2A1), aggrecan (AGG), and matrix metalloproteinase-13 (MMP-13) gene expression after prolonged cytokine exposure. Effects of short-term treatment with IL-α, IL-6, or IL-8 on endogenous GTP-bound Cdc42 levels were assessed using an affinity assay, and on actin filament organization using confocal microscopy. Cytokine treatments significantly decreased COL2A1 and AGG expression and increased MMP-13 expression. Short exposure to IL-1α, IL-6, or IL-8 decreased endogenous GTP-Cdc42 and increased stress fibers, which were reversed with cytochalasin D treatment. These results show that IL-mediated Cdc42 signaling modifies chondrocyte phenotype and morphology. This may lend insight into the altered chondrocyte phenotype in catabolic conditions such as osteoarthritis.

Survey of 11 western states for heartworm (Dirofilaria immitis) infection, heartworm diagnostic and prevention protocols, and fecal examination protocols for gastrointestinal parasites.

Heartworm infection in dogs and cats in the western United States is a fairly new phenomenon, and for this reason it is often considered to be of minimal significance. The purpose of this survey was to collect data from 11 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming) in an effort to assess awareness of heartworm disease and identify areas in which improvement in understanding is needed. To accomplish this goal, veterinary clinics and hospitals in these states were sent a one-page survey in early 2006. The results of the survey demonstrate that cases of heartworm disease have been reported in all 11 states, illustrating the importance of annual testing and the routine use of preventives.