Gout

peer reviewedIn the presence of a clinical acute monoarthritis, a differential diagnosis has to be made between septic arthritis, gout and diffuse chondrocalcinosis. Gout comes from a purine nucleotide metabolism disorder leading to serum urate level elevation. This hyperuricemia can lead to the deposition of monosodium urate crystals in the joints, causing acute attacks. After long-term evolution, others tissues as the kidneys can be involved: it is chronic gout. The definite diagnosis is based on the presence of monosodium urate crystals in the joint fluid. The diagnosis of gout should prompt a search for associated medical conditions that may affect both urate levels and longevity. These include alcoholism, various nephropathies, myeloproliferative disorders, and hypertension

Valdecoxib (Bextra)

peer reviewedValdecoxib (Bextra tablets of 10 mg and 20 mg) is a new non steroidal antiinflammatory drug (NSAID) that selectively inhibits COX-2 isoform of cyclo-oxygenase. It is indicated for the symptomatic treatment of osteoarthritis or rheumatoid arthritis (10 to 20 mg once a day) and for the treatment of primary dysmenorrhea (40 mg once a day). Valdecoxib is as efficacious as conventional non-COX-2 selective NSAIDs, but offers the advantage of a much better gastrointestinal tolerance. Valdecoxib has a prodrug that can be administered intravenously or intramuscularly (parecoxib, Dynastat) and has been developed for the short-term treatment of postsurgical pain

Biological therapies in rheumatology

peer reviewedBiological therapies consisting of monoclonal antibodies and soluble receptors have revolutionized the care of rheumatologic patients. These therapies ensued from a better understanding of the physiopathology of rheumatologic disorders. Most of the latter have been concerned: rheumatoid arthritis (for about 10 years), psoriatic arthritis and ankylosing spondilitys (for more or less five years). Rheumatology was among the first disciplines to make use of these advances; it continues to benefit from the results of intense research efforts. These developments request from clinicians an increased expertise in immunology

Hypervelocity impacts on thin brittle targets: experimental data and SPH simulations

The meteoroids and debris environment play an important role in the reduction of spacecraft life time. Ejecta or secondary debris, are produced when a debris or a meteoroid impact a spacecraft surface. These ejecta can contribute to a modification of the debris environment: either locally by the occurrence of secondary impacts on the component of complex and large space structures, or at long distance by formation of small orbital debris. This double characteristic underlines the necessity to model the damages caused by an HVI as well as the material ejection caused by the impact. Brittle materials are particularly sensitive to hypervelocity impacts because they produce features larger than those observed on ductile targets and the ejected fragments total mass including ejectas and spalls is in the order of 100 times bigger than the impacting mass. The main aim of this paper is to study the damaging and ejection processes that occur during hypervelocity impacts on thin brittle targets (dp = 500 microns for velocities ranging from 1 to 5 km/s). The two stage light gas gun “MICA” available at CEA-CESTA has been used to impact thin fused silica debris shields and the impacted samples have been analysed with environmental SEM microscopy and perthometer. Experimental characterization of ejected matter has also been performed on the MICA facility. The severe deformations occurring in any hypervelocity impact event are best described by meshless methods since they offer clear advantages for modeling large deformations and failure of solids as compared to mesh-based methods. Numerical simulation using the SPH method of Ls-Dyna and the Johnson Holmquist material model adapted for fused silica were performed at ENSICA. The results of these calculations are compared to experimental data obtained with MICA. Experimental data include the damage features in the targets (front and back spalled zone, perforation hole and cracks observed in the target) and the clouds and fragments ejected during the impact