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Effect of steep pulsed electric field on proliferation, viscoelasticity and adhesion of human hepatoma SMMC-7721 cells.

Anticancer Res. 2008 Jul-Aug;28(4B):2245-51

Authors: Song G, Qin J, Yao C, Ju Y

It has been proven that steep pulsed electric field (SPEF) can directly kill tumor cells and plays an important role in anticancer treatment. The biorheological mechanisms, however, that destroy tumor cells are almost unknown. To resolve this issue, here, an SPEF generator was used to assess the effects of high- and low-dose SPEF on the proliferation of human hepatoma SMMC-7721 cells by MTT assay, and on the viscoelasticity, adhesion of SMMC-7721 cells to endothelial cells by micropipette aspiration technique. Viability and proliferation of SPEF-treated SMMC-7721 cells were significantly inhibited. Cell cycle analysis indicated that SPEF arrested the cell cycle progression of SMMC-7721 cells at the G0/G1 transition to the S-phase. Viscoelastic data fitted by a standard linear solid model showed that viscoelasticity of SMMC-7721 cells changed after treatment with SPEF. Moreover, the adhesive force of low-dose SPEF-treated SMMC-7721 cells to endothelial cells markedly decreased compared to that of control cells. These results suggest that the suppressant effects of SPEF on the proliferation of SMMC-7721 cells appeared to be mediated, at least in part, through arresting cell cycle progression and altering the viscoelastic and adhesive properties of the cells, which provides a novel biorheological mechanism for the antitumor therapy of SPEF.

PMID: 18751402 PubMed - indexed for MEDLINE

Pulsed Magnetic Therapy

Principles of therapeutic use of transcranial and epidural cortical stimulation.

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Principles of therapeutic use of transcranial and epidural cortical stimulation.

Clin Neurophysiol. 2008 Aug 31;

Authors: Lefaucheur JP

Among the alternatives to drugs in the treatment of neurological and psychiatric disorders, neuromodulation techniques, including brain stimulation, have been used increasingly this past decade. Cortical targets are especially appealing, because they are easily accessible by noninvasive or invasive methods. Applicable techniques include repetitive transcranial magnetic stimulation (rTMS), transcranial electrical stimulation using pulsed or direct current, and epidural cortical stimulation (ECS) with surgically implanted electrodes. In contrast to deep brain stimulation in movement disorders or electroconvulsive therapy in depression, the efficacy of cortical stimulation to treat neurological or psychiatric disorders has not been yet clearly demonstrated. However, encouraging results have been reported in neuropathic pain (for ECS) and depression (for rTMS). In this review, we will consider some principles and mechanisms of action of these methods. First, it must be noted that fibers of intracortical or cortico-subcortical networks are more prone to be activated by the stimulation than cell bodies of local cortical neurons. Hence, the site(s) of action may be distant from the site of stimulation. In addition, various parameters of stimulation (such as stimulation frequency, intensity, or electrode polarity) and the configuration of the induced electrical field greatly influence the nature of the recruited circuits, and therefore, the overall efficacy. Finally, clinical changes may be delayed and prolonged beyond the time of stimulation, complicating programming algorithms in the case of implanted stimulation device. All these features need to be taken into account when considering cortical stimulation as a method of treatment.

PMID: 18762449 PubMed - as supplied by publisher

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