Here is an interesting article about a scientific advance that was made based on good information organization rather than based on experimentation.
Martha
Martha M. Yee
Cataloging Supervisor
UCLA Film & Television Archive
myee_at_ucla.edu
GOING BY THE BOOK
Jan 10th 2008
A group of Chinese scientists has discovered the main biochemical
pathways in drug addiction--and without having to do a single experiment
MODERN biology has a lot of "omes". The genome--all the genes that go
to make up an organism--is a familiar idea. The proteome--all the
different proteins--is becoming so. But there are also the
transcriptome (RNA), the glycome (sugars), the lipidome (fats) and the
metabolome (all the miscellaneous odds and ends not covered by the
others). And then there is the bibliome--all the mentions in research
papers of known biomolecules. There are now so many of these papers,
and the databases linking them are so good, that it is possible to use
scientific methods to investigate the bibliome in its own right, just
as any of the other, wetter "omes" may be investigated. Which is
exactly what a group of researchers from Peking University, led by Wei
Liping, have done to get at the biochemical heart of drug addiction.
Dr Wei and her colleagues wanted to answer three questions. First, what
are the genes and biochemical pathways in addiction? Second, does
addiction to different substances involve the same core biochemical
mechanisms? Third, does anything in those mechanisms explain why
addiction is so hard to shake off?
Many people, of course, have asked these questions before, and partial
answers have emerged. What Dr Wei hoped to do was to take these
fragmentary answers and patch them together to make something
approaching the whole truth. And, in a paper just published in the
PUBLIC LIBRARY OF SCIENCE, she seems to have managed just that.
IT LOOKS GOOD ON PAPER
Dr Wei's group looked at more than 1,000 studies of the biochemistry
and genetics of drug addiction. They were interested in the four sorts
of drug reckoned most addictive: alcohol, cocaine, nicotine and opiates
(heroin, methadone and so on). About 1,500 genes were implicated by one
or more of the studies, but in only 396 cases was that implication
backed by at least two independent lines of evidence. It was on these
confirmed cases that Dr Wei concentrated her fire.
Biochemistry is about pathways and networks of pathways. A pathway is a
series of enzymes (each of which is encoded in a gene) that perform a
task in sequence, like workers on an assembly line. Dr Wei therefore
ran her 396 genes through a database of all known pathways to see which
involved several enzymes encoded by those genes.
She found 18 that were involved in addiction to at least one type of
drug. Five, however, were common to all four types, and these five
pathways therefore look as though they are at the core of the process
of addiction. Three of the five were already under suspicion. Dr Wei's
result provided strong statistical evidence to back up what had just
been hunches. Two other pathways, however, had not previously been
considered as being involved in addiction.
The existence of these five central pathways helps explain a lot about
addiction. First, it gives weight to the belief that some people are
more susceptible to all sorts of addiction than others are. That
contrasts with the thought that addictions are substance-by-substance
phenomena, though the two ideas are not mutually exclusive since
changes in the 13 substance-specific pathways clearly also result in
addiction.
Second, the particular pathways involved help to explain why addiction
is so hard to reverse. Several of them take part in strengthening the
connections between nerve cells, which is the underlying basis of
learning. Unlearning something by breaking these connections is hard.
Third, Dr Wei was able to link the five central pathways together into
a network, and show that this network has four positive-feedback loops
in it. Work on other species in other contexts suggests that the
mixture of loops she found was one that often results in rapid and
irreversible biological processes--which is exactly what is seen in
addiction.
None of this, of course, directly helps the addict, though it
reinforces the message that it is better not to start taking these
drugs in the first place. But working out how the addiction machine
operates may point those looking for therapies in the right direction.
And this study also shows that the old cry "more research is necessary"
is not always true. Sometimes all you need to do is look at what you
already have in a different way.
See this article with graphics and related items at http://www.economist.com/science/displaystory.cfm?story_id=10493159
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Received on Thu Apr 03 2008 - 08:47:51 EDT