NONMEM Users Network Archive

Hosted by Cognigen

model dynamic data with $DES subroutine

From: Jing Nie <hollidayy>
Date: Thu, 3 Dec 2009 09:29:09 -0500


Dear NMusers,

I have a question I would like your help. The data I have is only the dyna=
mic data since we didn't give dose to the animal. I am trying to capture th=
e nature of disease progression. And the PD decrease with time. I have see=
n people model only the PD data use $PRED subroutine but they use the expli=
cit equation.But I want to use a differential equation like dA/dt= k=
in(1-dis)-kout*A while A0=kin/kout.

When I ran the control stream, the gradient for most of the parameters ar=
e 0. And the only parameter estimation I got is the sigma. The output of Y =
is 0. I guess it's because I don't have dose to compartment(PDK) but I don'=
t know how should I fix the problem.
Any suggestion is appreciated!

The control stream I wrote is:

$PROB Demo for turn over PD model
$INPUT ID TIME AMT PDK=DV EVID
$DATA demo.csv IGNORE=#

$ESTIM MAXEVAL=3000 NOABORT PRINT=1
METHOD=COND INTERACTION SIG=5 MSFO=save.msf

$COV MATRIX=S SLOW

$SUBROUTINE ADVAN6 TOL=5

$MODEL
COMP=(PDK)

$PK
KIN=THETA(1)*EXP(ETA(1))
KOUT=THETA(2)
DIS=THETA(3)*EXP(ETA(2))

$DES
DADT(1)=KIN*(1-DIS)-KOUT*A(1)

$ERROR
Y = F + ERR(1)

; Fixed effects
$THETA 174 FIX ; KIN
$THETA 77 FIX ; KOUT
$THETA (0,0.28,1) ; AGE_EFFECT_PDK

; Random effects
$OMEGA 0 FIX; BSVKIN_PDK
$OMEGA 0 FIX; BSVDIS_PDK


$SIGMA 0.1


$TABLE ID TIME PDK Y
NOPRINT ONEHEADER FILE=DEMO.fit



And my data looks like:
#ID TIME AMT PDK EVID
101 4 . 1.49 0
102 4 . 1.58 0
61 8 . 0.57 0
62 8 . 2.03 0
63 8 . 1.58 0
64 8 . 1.52 0
109 12 . 0.71 0
110 12 . 1.18 0
21 12 . 1.25 0


-Jing

 

 

This e-mail and any files transmitted with it, are intended solely for th=
e use of the individual or entity to whom they are addressed.?If you have r=
eceived this e-mail in error, please reply to this message and let the se=
nder know.


                                               
_________________________________________________________________
Chat with Messenger straight from your Hotmail inbox.
http://www.microsoft.com/windows/windowslive/hotmail_bl1/hotmail_bl1.aspx?o=
cid=PID23879::T:WLMTAGL:ON:WL:en-ww:WM_IMHM_4:092009=

Received on Thu Dec 03 2009 - 09:29:09 EST

The NONMEM Users Network is maintained by ICON plc. Requests to subscribe to the network should be sent to: nmusers-request@iconplc.com.

Once subscribed, you may contribute to the discussion by emailing: nmusers@globomaxnm.com.