We aimed to develop an active catheter that could be used safely in human blood vessels. We proposed and developed a new type of micro valve and incorporated this into a hydraulic pressure drive system with multi-degree of freedom, to produce an active catheter that was compact and required no electrical power for operation. We experimentally verified the good operational performance of a prototype of this active catheter. NTRODUCTION

Summary :C3H/HeN mice were infected with Echinostoma trivolvis metacercariae on day 0, given intramuscular injections of dexamethasone daily for 5 or 7 days, and necropsied on days 5, 8, 12, 1 5, 20 and 30 p. i. Controls consisted of mice that were infected with echinostomes, but were not treated with dexamethasone. Dexamethasone treatment caused a delay in worm expulsion from the small intestine of the hosts, and the increase in goblet cell numbers that occurred in untreated mice was markedly delayed in the treated mice. Mast cell number in the small intestine increased rapidly from just after day 5 p. i. and reached a peak on day 15 p. i. in both dexamethasone-treated and control mice, although the increase in cell numbers was delayed slightly in the dexamethasone-treated mice. The eosinophi number in the small intestine of dexamethasone-treated mice was suppressed until 8 days p. i. and then increased reaching a peak on day 1 2 p. i., although the number was about one half that of the control. As determined on day 1 2 p. i., the mean body area of worms from dexamethasone-treated animals was significantly greater than that of the controls. Histological examination of the small intestine showed that the goblet and Paneth cell hyperplasia seen in mice infected with E. trivolvis was suppressed by dexamethosone-treatment. Transmission electron microscopy revealed no marked ultrastructural differences in the small intestine of the dexamethasone-treated and control mice except that the former had an increased number of intracristal granules in mitochondria, an increase in vesicles in the apical epithelial cells and an increase in amorphous bodies and autophagic vacuoles in the Paneth cells. These results indicate that dexamethasone treatment delayed the expulsion of E. trivolvis from the small intestine of the host mouse in association with the suppression of goblet cell hyperplasia and increase in the number of mast cells and eosinophils.KEY WORDS : Echinostoma trivolvis, dexamethasone, gobl et cell hyperplasia, worm rejection, C3H/HeN mi ce. Résumé : L'EXPULSION DE ECHINOSTOMA TRIVOLVIS : EFFETS SUPPRESSEURS DE LA DEXAMÉTHASONE SUR L'HYPERPLASIE DES CELLULES CALICIFORMES ET L' ÉLIMINATION DES VERS CHEZ LA SOURIS C3H/HEN Des souris C3H/HeN ont été infectées à JO avec des métacercaires d'Echinostoma trivolvis, ont reçu quotidiennement de la dexaméthasone en intra-musculaire pendant 5 à 7 jours et ont été nécropsiées à J5, J8, J12, J15, J20 et J30. Des souris témoins ont été infectées par les échinostomes, mais n'ont pas été traitées par la dexaméthasone. Le traitement par la dexamethasone a provoqué un retard dans l'expulsion intestinale des vers par l'hôte, et l'augmentation du nombre des cellules caliciformes observé chez les souris non traitées a été nettement retardée chez les souris traitées. Le nombre de mastocytes intestinaux a rapidement augmenté juste après J5 et atteint un pic à J15 chez les souris traitées comme chez les témoins, bien que l'augmentation du nombre de cellules oit été légèrement retardée c...

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We proposed and developed an innovative active catheter with multisegments that can bend in the narrow blood vessel. Micro hydraulic actuator system based on new principle has been developed by the authors. Moreover, new micro fabrication method named hybrid stereolithograpy (IH process) requiring any assemble process is introduced for leakage-free packaging catheter. Total system with pressure control system was made. Good safety and drive performance were verified experimentally. We also devised theoretical models of these valves to facilitate quantitative design and to extend applications for safe medical tools.

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