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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 4 of 4. This is the beginning of the thread.
Posted by Larry Hoover on February 1, 2007, at 10:35:07
Testing for Cytochrome P450 Polymorphisms in
Adults With Non-Psychotic Depression Treated With
Selective Serotonin Reuptake Inhibitors (SSRIs)(November 2006)http://www.ahrq.gov/downloads/pub/evidence/pdf/cyp450/cyp450.pdf
Go to page 61 for the quick and dirty summary conclusions.
Lar
Posted by Phillipa on February 2, 2007, at 10:43:09
In reply to Report: P450 Polymorphisms and SSRIs, posted by Larry Hoover on February 1, 2007, at 10:35:07
Web-site is out. Love Phillipa
Posted by yxibow on February 3, 2007, at 0:36:48
In reply to Re: Report: P450 Polymorphisms and SSRIs » Larry Hoover, posted by Phillipa on February 2, 2007, at 10:43:09
> Web-site is out. Love Phillipa
Seems to work for me -- it is a PDF (Acrobat file)
The Amplichip is a fascinating concept not yet covered by most all insurance plans. I welcome more genetic testing which could determine why say, I am a fast metabolizer for certain medications.
Posted by Larry Hoover on February 5, 2007, at 7:18:47
In reply to Re: Report: P450 Polymorphisms and SSRIs » Phillipa, posted by yxibow on February 3, 2007, at 0:36:48
> The Amplichip is a fascinating concept not yet covered by most all insurance plans. I welcome more genetic testing which could determine why say, I am a fast metabolizer for certain medications.
The Amplichip concept is fatally flawed, IMHO. It works on the principle that double-stranded DNA conducts electricity, whereas single-stranded DNA does not. If I recall correctly, Amplichip has four DNA sequences for the 2D6 gene. Only subjects with those four variants will influence the device output current, whereas there are well over 100 known variants of this gene. Poor metabolizers with other variants will give false results, as will extensive metabolizers not identical to the test sequences.
What is needed, IMHO, is functional testing. It makes little difference which variant an individual has, so long as we know what the output/yield of that enzyme is. For example, dextromethorphan is a 2D6 substrate, and the ratio of DXM to O-desmethyl-DXM in urine is an excellent indicator of 2D6 function.
Other P450 enzymes with poor/extensive metabolizer variants are 3C9 and 1A3, if I recall correctly. Others may also be discovered. The Amplichip is too limited in scope to provide externally valid results.
Lar
This is the end of the thread.
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