Cortical Representation of Tympanic Membrane Movements due to Pressure Variation: An fMRI Study

Middle ear sensory information has never been localized in the homunculus of the somatosensory cortex (S1). We investigated the somatosensory representation of the middle ear in 15 normal hearing subjects. We applied small air pressure variations to the tympanic membrane while performing a 3T-fMRI study. Unilateral stimulations of the right ear triggered bilateral activations in the caudal part of the postcentral gyrus in Brodmann area 43 (BA 43) and in the auditory associative areas 42 (BA 42) and 22 (BA 22). BA 43 has been found to be involved in activities accompanying oral intake and could be more largely involved in pressure activities in the oropharynx area. The tympanic membrane is indirectly related to the pharynx area through the action of tensor tympani, which is a Eustachian tube muscle. The Eustachian tube muscles have a role in pressure equalization in the middle ear and also have a role in the pharyngeal phase of swallowing. Activation of BA 42 and BA 22 could reflect activations associated with the bilateral acoustic reflex triggered prior to self-vocalization to adjust air pressure in the oropharynx during speech. We propose that BA 43, 42, and 22 are the cortical areas associated with middle ear function. We did not find representation of tympanic membrane movements due to pressure in S1, but its representation in the postcentral gyrus in BA 43 seems to suggest that at least part of this area conveys pure somatosensory information

Biosynthesis and Toxicological Effects of Patulin

Patulin is a toxic chemical contaminant produced by several species of mold, especially within Aspergillus, Penicillium and Byssochlamys. It is the most common mycotoxin found in apples and apple-derived products such as juice, cider, compotes and other food intended for young children. Exposure to this mycotoxin is associated with immunological, neurological and gastrointestinal outcomes. Assessment of the health risks due to patulin consumption by humans has led many countries to regulate the quantity in food. A full understanding of the molecular genetics of patulin biosynthesis is incomplete, unlike other regulated mycotoxins (aflatoxins, trichothecenes and fumonisins), although the chemical structures of patulin precursors are now known. The biosynthetic pathway consists of approximately 10 steps, as suggested by biochemical studies. Recently, a cluster of 15 genes involved in patulin biosynthesis was reported, containing characterized enzymes, a regulation factor and transporter genes. This review includes information on the current understanding of the mechanisms of patulin toxinogenesis and summarizes its toxicological effects

Tests cognitifs utilisables par le médecin généraliste pour le diagnostic précoce de la maladie d'Alzheimer (revue de la littérature dans la base de données Medline de 1995 à septembre 2005)

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Burkholderia pseudomallei Requires Zn(sup2+) for Optimal Exoprotease Production in Chemically Defined Media

The effects of various medium components on exoprotease production by Burkholderia pseudomallei were studied in order to understand the production of virulence factors by this pathogenic organism. FeSO(inf4), NaCl, and MgSO(inf4) do not significantly affect exoprotease activity, and CaCl(inf2) has only a slight influence. Conversely, ZnCl(inf2) plays a fundamental role since it drastically increases exoprotease production.</jats:p

Intérêt des anticorps recombinants dans la protection médicale contre les agents du bioterrorisme : l'exemple de la maladie du charbon

Les anticorps recombinants forment une classe thérapeutique en plein essor ; ils sont particulièrement bien adaptés à la prise en charge du risque biologique agressif grâce à leur action immédiate et fréquemment synergique avec les autres molécules thérapeutiques existantes, leur longue demi-vie et leur bonne tolérance. Le charbon est une maladie de première importance concernant ce risque, et sa pathogénie dépend de toxines qui peuvent être neutralisées par les anticorps. Ces toxines sont formées par l'association de trois types de sous-unités (PA, LF, EF). Plusieurs anticorps recombinants anti-PA ont été développés, y compris par notre équipe, en utilisant une approche originale. Nous avons également développé un anti-LF, conformément aux recommandations des experts. Notre anticorps anti-PA, et dans une moindre mesure notre anti-LF, seront présentés