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Occupational Applications : We investigated the effects of seat pan inclination and foam on the deformation of the seated buttocks using an upright MRI system. From observations among four healthy males, we found that soft tissue deformation under the ischial tuberosity (IT) could be reduced not only by using a soft cushion, but also by decreasing the shear force on the seat pan surface. These results suggest that soft tissue deformation could be used as an objective measure for assessing seating discomfort and injury risk, by accounting for the effects of both contact pressure and shear. We also confirmed that the gluteus maximus (GM) muscle displaced away from the IT once seated. As peak pressure and shear are most likely located below the IT, more realistic computational human body models in this region are needed that consider muscle sliding. Technical Abstract: Background: A full understanding of soft tissue deformations, particularly in the gluteal region in a seated position, would be helpful for improving seat comfort and reducing the injury risk of seated people. Thanks to recent developments in medical imaging, direct observations of soft-tissue deformations under realistic loading conditions is now possible using open MRI. PURPOSE: The purpose of this work was to investigate the effects of seat pan inclination and foam on the deformation of soft tissues in the gluteal region using an open MRI. METHODS: Four healthy male participants completed the experiment, in which a positional MRI scanner was used to scan the buttocks and part of the thighs. Three seating conditions were tested by varying the seat pan angle (A_SP) and cushion material while the backrest was fixed at 22 degrees from the vertical: 1) A_SP =7° without foam (Reference); 2) A_SP =0° without foam (Shear); 3) A_SP =7° with a 50mm thick foam on the seat pan (Foam). In addition, one configuration (Unloaded), with the buttocks being unsupported, was also scanned for comparison. After segmenting images, we calculated the volumes of the gluteus maximus (GM) muscle and subcutaneous fat in three regions of interest under the ischial tuberosity (IT) for each condition. RESULTS: Once seated, the GM displaced away from the IT laterally and posteriorly. For all participants, the largest tissue deformation was observed in the Shear condition, while the smallest was found in the Foam condition. CONCLUSIONS: The present study provides quantitative data needed for validating buttock-thigh finite element models. Future work is needed to link soft tissue deformation with discomfort perception.

The flow around two airfoils in the vicinity of stall has been experimentally investigated in the ONERA/CFM F2 wind tunnel. The aim of this study was to provide a detailed and well established database for CFD validation, in low speed conditions (M∞=0.15) for a fixed Reynolds number of 2.1×106 based on the chord. The 2D single element models were fitted with wall pressure taps allowing the measurement of pressure distributions and the determination of the lift coefficient. Measurements over a wide range of angles of attack provided a global view of the phenomena. The first airfoil typically exhibits an abrupt stall, while the second one is characterized by a very mild one. The main part of this study was a very careful survey of the suction side boundary layer and near wake, using the F2 LDA system in a 2D configuration. This first part deals with the boundary layer surveys. A companion paper presenting the wake results will be issued later.

Splenic lymphoma with villous lymphocytes (SLVL) is a low grade lymphoproliferation characterized by a massive splenomegaly, an absence of lymphadenopathy and the presence in the peripheral blood of atypical B-lymphocytes with hairy-cell appearance. We have studied the morphological, immunological and molecular characteristics of 3 cases of SLVL. SLVL presented on blood smears characteristic irregularities of the plasma membrane consisting in thin and short villi unevenly distributed. The main phenotype was CD5-, CD11c+, and CD25-, but individual SLVL cases can not be identified by using immunohistochemical criteria alone. Clonal rearrangements of the immunoglobulin heavy chain gene were found in all 3 cases and in one case presented a bcl2-JH rearrangement. SLVL are clonal B-cell lymphoproliferations and can be associated with t(14; 18) translocation.

Certains aspects des reactions immunitaires et des troubles de la coagulation sont etudies chez des lapins infestes par deux souches de Trypanosoma (Trypanozoon ) equiperdum determinant des affections d’allure clinique differente.L’etude des anticorps antitrypanosomes met en relief le caractere tres immunogene de la glycoproteine specifique de type dont l’antigenicite parait s’exercer au detriment des structures antigeniques communes.La presence d’auto-anticorps anti-fibrinogenes a des titres assez eleves pose le probleme de la signification des auto-anticorps frequemment deceles au cours des trypanosomoses. Du fait de leur nature IgM, ils contribuent a l’hypermacroglobulinemie classique dans ces affections. Leur participation eventuelle dans la pathogenie des troubles observes est discutee.La signification de l’activation du systeme fibrinolytique dont temoigne la presence de PDF est egalement discutee : fibrinolyse reactionnelle ou activation du facteur Hageman par des immuns-complexes.

Trypanosoma equiperdum conserve sa virulence et se developpe dans des chambres de diffusion “Millipore” implantees sous la peau de la region dorsale de la souris. La multiplication des parasites est rapide dans les jours qui suivent l'implantation a condition que leur nombre initial soit faible (100 trypanosomes par exemple). La courbe de croissance atteint en 5 a 6 jours un maximum, puis s'inflechit vraisemblablement en raison de l'intervention des anticorps elabores par la souris contre les antigenes parasitaires. Ce flechissement ne s'observe pas si les souris sont traitees par le cyclophosphamide. L'oxisuran, depresseur de l'immunite thymodependante, n'a qu'un effet plus reduit. Les souris, ayant heberge pendant au moins 10 jours une chambre de diffusion, presentent par la suite un etat de resistance a l'infestation par le meme parasite. Les trypanosomes, places dans des chambres de diffusion implantees chez des souris maintenues a 35 C, se developpent plutot mieux qu'a la temperature ordinaire. L'influence de la temperature sur la virulence de T. equiperdum pour la souris ne s'explique donc vraisemblablement pas par un effet direct sur le parasite.

Resume Les auteurs ont etudie l'influence d'un sejour prolonge en haute altitude (Font-Romeu : 1 800 m) sur le taux des IgE seriques d'enfants asthmatiques, en dehors de toute medication et en l'absence de toute crise. Les IgE ont ete dosees par radio-immunodiffusion (technique de Rowe modifiee) dans des serums preleves a intervalles de temps reguliers, chez 38 enfants asthmatiques et 10 enfants non allergiques servant de temoins. Les taux a l'arrivee (moyenne geometrique : 895,2 UI/ml) sont voisins des chiffres habituellement signales chez les asthmatiques. Apres trois mois de sejour, le taux moyen a chute d'environ 25 p. cent, apres six mois de pres de 50 p. cent (differences statistiquement tres significatives). A l'inverse, chez les temoins non allergiques, le taux des IgE n'est pas altere par le sejour en altitude. Les autres immunoglobulines (IgG, IgA et IgM) ne subissent aucune variation significative, tant chez les temoins que chez les asthmatiques. Plutot que la consequence d'un effet specifique de l'altitude sur la biosynthese des anticorps reaginiques, il semble qu'il faille voir dans cette chute etroitement concordante du taux des IgE au cours du sejour a Font-Romeu, le resultat d'un sevrage de sollicitations antigeniques, dans une atmosphere seche et hypo-allergenique.

Resume A l'occasion de l'enquete etiologique de certaines allergies professionnelles chez des sujets asthmatiques au contact de la farine ou des cereales (ouvriers agricoles, ouvriers de meunerie, boulangers…), un antigene de l'insecte Ephestia kuehniella, a pu etre isole. L'analogie avec d'autres affections respiratoires dites a « precipitinesa fait rechercher la presence d'anticorps precipitants a cet insecte. Leur mise en evidence a ete realisee dans plus de la moitie des cas explores. La quasi-totalite d'entre eux presentaient par ailleurs, des tests cutanes immediats, fortement positifs a l'antigene d'Ephestia. Il semblerait que ces formes comptent parmiles plus graves du lot des allergies a l'Ephiestia. Toutefois, elles ne paraissent pas presenter le tableau clinique caracteristique que d'aucuns ont voulu decrire dans les maladies dites a « precipitines . L'echec des tentatives de desensibilisation a l'Ephestia et l'augmentation du taux des anticorps precipitants qu'elles entrainent frequemment, font poser a la fois le probleme du role de ces anticorps et celui de l'indication de la desensibilisation en leur presence, dans ce cas precis et a propos d'antigenes similaires.

Resume Au cours des differents syndromes allergiques etudies (pollinose nasale, rhinite aperiodique, asthme et urticaire) seules sont interessantes a considerer les variations des IgE, immunoglobulines connues pour etre le support des proprietes reaginiques. Malgre les taux tres eleves souvent observes chez ces malades, le dosage des IgE seriques ne semble pas suffisant a lui seul pour affirmer on infirmer avec certitude la nature atopique des manifestations presentees. Des variations individuelles considerables en fonction de facteurs parfais connus (parasitoses) mais souvent encore mal precises rendent l'interpretation difficile. Confronte a d'autres arguments cliniques et biologiques, un taux eleve d'IgE nous parait cependant un element de valeur en faveur d'un terrain atopique.

Resume La tularemie est une maladie infecticuse commune a certaines especes animales. En France, la transmission a l'enfant n'est pas tres frequente mais elle sevit a l'etat endemique dans le Centre, Sud-Ouest et surtout Nord-Est. En Pediatrie, on observe surtout des formes pharyngoganglionnaires. Les plus âges des enfants presentent des formes ulcero-ganglionnaires consecutives au contact d'animaux infectes. Le diagnostic repose sur la mise en evidence des germes sur milieux speciaux et surtout sur le sero-diagnostic et l'I.D.R. a la Tularine. Grâce aux antibiotiques et notamment a la Streptomycine, le pronostic des formes graves a ete considerablement ameliore.

The cure of Trypanosoma equiperdum infected Mice obtained after treatment with an association of electromagnetic waves and a magnetic field is probably linked with the immune state of the host. A severe depression of the immune system suppresses the ability of the animals to eliminate the parasites after physical stimulation.

Different evolutions of experimental trypanosomiasis are observed in Mice kept in a permanent 35 degrees C environment. Evolution depends on the individuality or the strain of the host animal. An experimental factor influence on the host mechanism defense rather than on the parasite multiplication rate is shown.

Staphylococcus aureus (60 p. 100) and Candida albicans (50 p. 100) were mostly found in 73 cases of diaper dermatitis. They were present together in 16 out of these 73 cases. This study enables us to think this is a matter of opportunistic infection. Staphylococcus aureus (75 p. 100) and beta-hémol. Streptococcus A (28 p. 100) were found in 40 children with impetigo contagiosa. They were present together in 7 out of the 40 cases. Nephritis was never found either in those cases or in other 93 cases of pyodermitis.

Some aspects of immune response and coagulation disorders are investigated on rabbits infected by two strains of Trypanosoma (Trypanozoon) equiperdum giving diseases with different clinical expression. The study of antibodies to trypanosomes emphasizes the high immunogenicity of specific antigenic type glycoprotein, antigenicity of which seems to inhibit common antigens expression. Significant increase of anti-fibrinogen antibodies is discussed in relation with the presence of autoantibodies frequently discovered along trypanosomiasis. As IgM they contribute to the classical hypermacroglobulinemia of these diseases. Their casual contribution in the contribution in the casual contribution in the observed disorders is argued. The meaning of fibrinolytic system activation which is shown by FDP significant increase is equally argued: secondary fibrinolysis or Hageman Factor activation mediated by immune complexes.