Molecular mechanisms of Salmonella pathogenesis

The success of a pathogen depends on its capacity to enter a host, circumvent host defense barriers and establish infection. The Gram-negative bacterium Salmonella enterica has evolved different strategies to subvert normal host cellular functions, which allow it to enter into and proliferate within host cells.     

Evaluation of hemostasis by the Clot Signature Analyzer: a potentially valuable device for the anesthesiologist

Rapid detection of hemostatic defects presents a challenge for the anesthesiologist who must balance anesthetic and surgical considerations for maintaining adequate platelet and coagulant factors, while keeping allogenic blood exposure to a minimum. The Clot Signature Analyzer®, a point-of-care device capable of rapid response and easy interpretation is described here. Its applicability in two obstetrical patients with platelet dysfunction is discusssed.     

Mechanistic investigation of the anodic oxidation of p-methoxytoluene in dry and wet acetonitrile

Alkyl aryl ethers are oxidized in acetonitrile in two very closely spaced waves. A detailed investigation has been carried out in the case of p-methoxytoluene, using both voltammetry and preparative electrolysis. The kinetics of the first anodic peak correspond to a second order rate law, both in anhydrous medium, and in the presence of water. On the preparative scale, the controlled potential electrolysis at a potential located on the first wave gives different products depending on the operating conditions. When small amounts of water were present, two new compounds were obtained as the major products: a 2,5-cyclohexadienone substituted in the 4 position by the starting compound, and the phenol resulting from an acid catalyzed rearrangement of this cyclohexadienone. A mechanism accounting for the nature of the reaction products in wet acetonitrile is proposed on the basis of the voltammetric and coulometric data as well as of the result of the electrolysis performed in the presence of ¹⁸O labeled water.     

Intrathoracic Pott's abscesses, radiologic pitfalls for the pneumologist

The authors have conducted a retrospective study of 200 cases of tuberculous spondylitis, and wish to draw attention to the clinical and, chiefly, radiological aspects of the disease. Intrathoracic Pott's abscesses are principally observed in developing countries but they are not exceptional in France, and their varied semeiology deserves to be described.     

Wallerian degeneration after cerebral infarction: evaluation with sequential MR imaging

The dynamic signal intensity changes at magnetic resonance (MR) imaging in active and chronic wallerian degeneration in the corticospinal tract were evaluated. Forty-three patients with wallerian degeneration seen on MR images after cerebral infarction were studied. When possible, patients with acute stroke were examined with MR imaging prospectively at the onset of symptoms and then at weekly intervals for several months. Focal infarction without distal axonal degeneration is demonstrated for the 1st month following onset of clinical symptoms. At 4 weeks, a well-defined band of hypointense signal appears on T2-weighted images in the topographic distribution of the corticospinal tract. After 10-14 weeks, the signal becomes permanently hyperintense. Over several years, accompanying ipsilateral brain stem shrinkage occurs. The dark signal intensity observed on T2-weighted images between 4 and 14 weeks is believed to result primarily from transitory increased lipid-protein ratio.     

Specificity of persistence of antibody to the streptococcal group A carbohydrate in rheumatic valvular heart disease

The specificity of the persistence of antibody to the streptococcal group A carbohydrate for mitral valve disease induced by rheumatic fever was examined. Levels of the antibody were determined in serum samples of 30 patients with rheumatic mitral insufficiency, 30 patients with mitral valve prolapse, and an equal number of normal individuals and patients with congenital heart disease. Antistreptolysin titers and anti-deoxyribonuclease B titers were also assayed in all sera. There were no differences in the incidence of elevated antibody titers or in the geometric means of the antibody titers for the normal individuals, the patients with congenital heart disease, and the patients with mitral valve prolapse. In contrast, the frequency of elevated anti-streptococcal group A carbohydrate titers and the geometric means of these titers were significantly higher in the patients with rheumatic mitral valve disease than in patients with mitral valve prolapse. This confirms the specificity of the persistent elevation of anti-streptococcal group A carbohydrate to patients with mitral valve disease induced by rheumatic fever and also suggests that the persistence of this antibody in patients with rheumatic valvular disease is not a result of a functional abnormality of the mitral valve.