Abstract. C3H/10T1/2 mouse embryo fibroblasts were stimulated by a steady electric field ranging up to 10 V/cm. Some cells elongated and aligned perpendicular to the field direction. A preferential positional shift toward the cathode was observed which was inhibited by the calcium channel blocker D-600 and the calmodulin antagonist trifluoperazine. Rhodaminephalloidin labeling of actin filaments revealed a fieldinduced disorganization of the stress fiber pattern, which was reduced when stimulation was conducted in calcium-depleted buffer or in buffer containing calcium antagonist CoC12, calcium channel blocker D-600, or calmodulin antagonist trifluoperazine. Treatment with calcium ionophore A23187 had similar effects, except that the presence of D-600 did not reduce the stress fiber disruption.The calcium-sensitive photoprotein aequorin was used to monitor changes in intracellular-free calcium. Electric stimulation caused an increase of calcium to the micromolar range. This increase was inhibited by calcium-depleted buffer or by CoC12, and was reduced by D-600. A calcium-dependent mechanism is proposed to explain the observed field-directed cell shape changes, preferential orientation, and displacement. DRECTED and coordinated cell movement plays a determining role during embryonic development and wound healing. In motile tissue cells such as fibroblasts and epithelial cells, natural movement is generated by localized instabilities of the cell periphery that allow one or more leading lamellae to extend outward (19). The propulsive forces responsible for lamellar extension are generated by a mechanism believed to be regulated by calcium (5, 34), and the direction of movement is dictated by the broadest and strongest leading lamella (1, 43). Several factors are believed to direct cell shape changes and movement. These include intrinsic factors programmed within the cell as well as extrinsic influences such as chemotaxis, galvanotaxis (electric field directed), contact guidance, haptotaxis, and contact inhibition (43).Recently, the role played by electric fields has attracted the research efforts of a number of investigators (30). This influence was first studied by Verworn in 1889 (44), and many of the related early works were reviewed by Lund in 1947 (24). In 1966 Jaffe demonstrated that developing Fucus zygotes in a multi-cell system generates endogenous transcellular currents (22). The need for spatial and temporal resolution led to the development of the ultrasensitive vibrating probe technique (23), and since then numerous laboratories have been able to measure ionic current patterns in developing embryonic systems (29) and at sites of injury (7). In the past few years, there has also been a growing interest in the effects of an applied electric field on cells in culture (38).In an earlier work, we observed the electric field-induced cell shape changes and preferential alignment of C3H/10T1/2 mouse embryo fibroblasts (47). Subsequently, we provided evidence showing that the response was mediated through an ...

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Although, there is a substantial difference in the overall diagnostic accuracies, it is not statistically significant. Therefore, we conclude that magnifying colonoscopy is at least as accurate as EUS for preoperative staging of early CRCs.

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