Re: Correct codes of modeling Michaelis-Menten elimination usingconcentration-time data

From: Lewis B Sheiner <lewis@c255.ucsf.edu> Subject: Re: Correct codes of modeling Michaelis-Menten elimination usingconcentration-time data Date: Fri, 29 Sep 2000 09:29:09 -0700 There is no scaling in DES. The reason for the difference is that the standard definition of Vm is a maximum rate, i.e. amount/time. The Users Guide equation uses that convention. If you do not scale A(1) by S(1) then the Vm estimate you get is really Vm/Vd, with units of concentration per time. This is the parameter Dr Li uses (e.g. "Vm=0.253 mg/(ml*hr)"); it is no mistake to redefine a parameter in this way if one chooses, so long as the definition is clearly stated and the usage is consistent. However I believe it is inadvisable in this instance to do so. To minimize confusion, we should try, I think, to stick to the the conventions of the fields from which we borrow. LBS. _______________________ _/ _/ _/_/ _/_/_/ _/_/_/ Lewis B Sheiner, MD (lewis@c255.ucsf.edu) _/ _/ _/ _/_ _/_/ Professor: Lab. Med., Biophmct. Sci., Med. _/ _/ _/ _/ _/ Box 0626, UCSF, SF, CA, 94143-0626 _/_/ _/_/ _/_/_/ _/ 415-476-1965 (v), 415-476-2796 (fax)