By opposing poles you mean 2 north and 2 south?

Thanks for the refs. I have seen the Vanderbilt site (school of
Nursing)....

You might want to look at what Stefan Engstrom had to say in the
"bioelectromagnetics" newsgroup on this on, as well.

regards

Scott

--- In magnotherapy@y..., JBainSI@a... wrote:
> The Magnablock is a set of magnets with 4 opposing poles directed to
the
> person.
>
> Efficacy Of A Static Magnetic Device Against Knee Pain Associated
With
> Inflammatory Arthritis
> Neil Segal, Joseph Houston., Howard Fuchs, Robert Holcomb, Michael
J. McLean
> Vanderbilt University Medical School; Division of Rheumatology,
Department of
> Medicine; and, Department of Neurology Vanderbilt University Medical
Center
> Snip
> "In this study, we examined the efficacy of treatment with a static
magnetic
> field generator as adjunctive therapy for the joint pain in patients
with
> inflammatory arthritis. The MagnaBlocĂ" (MB; U.S. patent no
5,312,321) is a
> non-invasive non-significant risk device, consisting of four
permanent
> magnets arrayed with alternating polarity in a hypoallergenic
plastic case.
> The MagnaBloc™ is approximately 3.5 centimeters in diameter,
weighs
> approximately 30 grams and generates a magnetic field of 190
millitesla. This
> device reduced mechanical low back pain and knee pain significantly
more than
> placebo. Much larger time invariant magnetic fields like those
produced by
> magnetic resonance imaging devices have not been shown to be harmful
to man
> or animals "
>
> Thwere are about 20 studies from Holcomb on the device which he
believes
> works due to the steep field gradients, and has studies which seem
to confirm
> this.
>
> Measurement And Analysis Of Static Magnetic Fields Which Block
Action
> Potentials In Cultured Neurons
> A.V. Cavopol, A.W. Wamil, R.R. Holcomb and M.J. McLean
> Bioelectromagnetics 16:197-206, 1995.
> To characterize the algebraic properties of static magnetic fields
on firing
> of action potentials (AP) by sensory neurons in cell culture, we
developed a
> mathematical formalism based on the algebraic expression of the
magnetic
> field of a single circular current loop. The calculated fields fit
closely
> the field measurements taken with a Hall effect gaussmeter. The
biological
> effect induced by different arrays of permanent magnets depended
principally
> on the spatial variation of the fields, quantitated by the value of
the
> gradient of the field magnitude. Magnetic arrays of different sizes
> (macroarray: four center-charged neodymiurn magnets of ~14 mm
diameter;
> microarray: four micromagnets of the same material but ~0.4 mm
diameter)
> allowed comparison of fields with similar gradients but different
intensities
> at the cell position. These two arrays had a common gradient value
of ~1
> mT/mm and blocked > 70% of AP. Alternatively, cells placed in a
field
> strength of ~0.2mT and a gradient of ~0.02mT/mm produced by the
macroarray
> resulted in no significant reduction of firing; a microarray field
of the
> same strength but with a higher gradient of ~1.5mT/mm caused ~80% AP
> blockade. The experimental threshold gradient and the calculated
threshold
> field intensity for blockade of action potentials by these arrays
were
> estimated to be ~0.02 mT/mm and ~0.02 mT, respectively. In
conclusion, these
> findings suggest that spatial variation of the magnetic field is the
> principal cause for AP blockade in dorsal root ganglia in vitro.
>
> Best wishes
> --
> John Bain
> UK TV Sound Director, magnotherapy user & distributor
> http://members.aol.com/JBainSI/Magnotherapy.html
> Surround Sound for Television