Insertion Of X-Ray Structures Of Proteins In Membranes

Few structures of membrane proteins are known and their relationships with the membrane are unclear. In a previous report, 20 X-ray structures of transmembrane proteins were analyzed in silico for their orientation in a 36A-thick membrane [J. Mol. Graph. Model. 20 (2001) 235]. In this paper, we use the same approach to analyze how the insertion of the X-ray structures varies with the bilayer thickness. The protein structures are kept constant and, at each membrane thickness, the protein is allowed to tilt and rotate in order to accommodate at their best. The conditions are said to be optimal when the energy of insertion is minimal. The results show that most helix bundles require thicker membranes than porin barrels. Moreover, in a few instances, the ideal membrane thickness is unrealistic with respect to natural membranes supporting that the X-ray structure requires adaptation to stabilize in membrane. For instance, the squalene cyclase could adapt by bending the side chains of its ring of lysine and arginine in order to increase the hydrophobic surface in contact with membranes. We analyzed the distribution of amino acids in the water, interface and acyl chain layers of the membrane and compared with the literature

Syndrome de Sweet vésiculo-bulleux

Un homme de 74 ans souffrant d’une myélodysplasie de type anémie réfractaire avec excès de blastes suivait un traite-ment par azacitidine depuis 2 semaines à raison de deux injections abdominales sous-cutanées par jour. Il développait deux zones érythémateuses indurées centrées sur les sites d’injections avec une douleur importante, associées à une altération de son état général, avec fièvre et fris-sons qui n’étaient pas été améliorées lors de l’arrêt des injections d’azacitidine et d’un traitement antibiotique. Le patient avait une induration importante de toute la paroi abdominal

Impact of irradiation damage recovery during transportation on the subsequent room temperature tensile behavior of irradiated zirconium alloys

16th International Symposium on Zirconium in the Nuclear Industry, 9th May 2010 – 13th May 2010, Chengdu, Sichuan Province, ChinaInternational audienceZirconium alloys are commonly used in Pressurized Water Reactor as fuel rod cladding tubes. After irradiation and cooling in pool, the Spent Nuclear Fuel Assemblies are either transported for wet storage to a devoted site or loaded in suitable casks for dry storage on Nuclear Power Plant site. During dry transportation or at the beginning of dry storage, at temperatures around 400°C, the cladding experiences a creep deformation under the hoop stress induced by the internal pressure of the fuel rod. During creep a recovery of the radiation damage can occur that can affect the subsequent mechanical properties. The mechanical behavior of the cladding has been investigated in laboratory on two neutron irradiated cladding materials: fully recrystallized Zr-1%Nb and stress relieved Zircaloy-4. Creep tests under internal pressure were conducted at 400°C and 420°C. After depressurization and cooling, ring tensile tests were carried out at room temperature. In addition, Transmission Electron Microscopy observations have been performed after testing. The post-creep mechanical response exhibited a decrease of the strength compared to the asirradiated material. This decrease is associated with a significant recovery of the ductility, which becomes close to the ductility of the unirradiated material. The Transmission Electron Microscopy examinations, especially conducted on recrystallized Zr-1%Nb ring samples, revealed that the radiation defects have been annealed. It was also observed that, as for the unirradiated material, the deformation occurred homogeneously throughout the grains. No dislocation channel was indeed observed contrary to the as-irradiated material. These observations explain the recovery of the strength and of the ductility after post-irradiation creep that may occur during dry transportation or at the beginning of dry storage

Extracorporeal lithotripsy--the Direx system. Preliminary results at Liege University

peer reviewe

Skin signs in the diagnosis of thallium poisoning.

A 45-year-old man developed a painful and rapidly progressive sensory-motor polyneuropathy associated with confusion and convulsions. This resulted in hypoventilation and led to respiratory failure and coma. A rapid and diffuse alopecia occurred after 3 weeks in the intensive care unit. Examination of hair roots under polarized light detected dystrophic anagen hairs with dark bands caused by empty spaces in the disorganized cortex. These dark zones were originally reported in patients with thallium poisoning and a toxicological investigation confirmed thallium exposure. The classical systemic symptoms and the various dermatological signs are reviewed, and the origins of contamination and physiopathology discussed

Clear cell 'sugar' tumor (PEComa) of the skin: A case report

The so-called perivascular epithelioid cell neoplasm (PEComa) family includes angiomyolipoma, clear cell 'sugar' tumor (CCST), lymphangioleiomyomatosis, and clear cell myomelanocytic tumor (CCMMT). These rare tumors are characterized by the co-expression of melanocytic and muscle markers. They have been recognized in an increasing number of sites but currently only one case of PEComa, of the CCMMT subtype, has been reported in the skin in abstract form. We provide the clinicopathologic description of a case of extrapulmonary CCST located in the dermis and superficial subcutis of the thigh of a 60-year-old female. The lesion was composed of nests of epithelioid and spindle cells with abundant clear to granular cytoplasm and distinct cell borders. The tumor showed strong and diffuse immunoreactivity with HMB-45. Scattered cells expressed desmin and h-caldesmon. Antibodies to S-100 protein, melan-A, cytokeratins, and smooth muscle actin were negative. This first case of cutaneous PEComa of the CCST type expands the differential diagnosis of clear cell/granular cell tumors of the skin. © Blackwell Munksgaard 2005.SCOPUS: ar.jFLWINinfo:eu-repo/semantics/publishe