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Jean-Philippe GÉRARD jpg at pasteur.fr
Mon Apr 21 17:15:51 EST 1997

I am trying to get informations about the implication of 
ORGANIC SILICON  in general metabolism.

I've just read an article published in Nature (1997) about
the cloning of a silicon transporter in C. fusiformis (alga).

I know that some tissues in mammalian are 'rich' in silicon
(skin, arteries, thymus, eye, ...),
that silicon is particularly present in the glycosaminoglucan fraction
of the extracellular matrix.
It interferes most probably with cholesterol (steroids ?) metabolism.
Silicon also prevents alumin(i)um toxicity in fish.
In soil, soluble silica helps the mobilization of phosphates.

On the other hand, some forms of crystalline silica cause silicosis,
and are implicated in scleroderma.  Asbestos is a particular
alumino-silicate --> asbestosis.
In vitro, excess silica provokes the secretion of IL-1
(Interleukine-1) and kills macrophages.

Colloidal silica is also used as excipient for numerous drugs.
<--> very limited or no toxicity.

I'd like to summarize the general knowledge about this (not so rare)

I also have a 'problem' with the period 
of the radioactive isotope 32Si (beta -, 220 KeV)
The Table of Radioactive Isotopes (E. Browne & R.B. Firestone)
gives 104 years (value also given by LANL)
while it appears with a 650 y period in the
Handbook of Chemistry and Physics (62nd edition). !!!

Does anybody out there could help ? (or know somebody...) 

MERCI d'avance.

______________________________________              _____
                        jpg at pasteur.fr          _____  __o
           The ideal doctor is patient       ------   -\<,
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