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Hi all,
Does anybody know the average rat intestine surface area? For
example, human radius of the small intestine (1.75cm) and a length of
6m give a value for 0.66m2. It is understandable the actual
absorptive area is increased considerably by the presence of villi and
microvilli, but I need information to estimate the physiological
intestinal surface area of rat.
Thanks!
Guoyu
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Hi Guoyu,
Please check this journal...
J Anat. 1985 August; 141: 1-17.
PMCID: PMC1166384
Crypts, villi and microvilli in the small intestine of the rat. A
stereological study of their variability within and between animals.
T M Mayhew and C Middleton
--
Published in: Scandinavian Journal of Gastroenterology, Volume 26,
Issue 12 December 1991 , pages 1240 - 1246
Mucosal Surface Area of a Reversed Intestinal Segment in Rats
Kind Regards
Chandramouli Radhakrishnan
moulirc.aaa.hotmail.com
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The following message was posted to: PharmPK
Guoyu: See the following site:
http://www.rivm.nl/interspeciesinfo/intra/rat/int_small/db_rat_small_intestine.jsp
As a conservative rule, get at least three references such as that
above and
average.
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Dear Guoyu,
You can refer paper on Davies & Morries on physiological parameters of
various animals (Pharm Research Vol 10,No.7,1993). Rat intestinal
Surface area according to it is 0.023m2.
anybody can correct me if iam wrong
Regards
Harish
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Dear Guoyu,
As I have read in articles the average rat small intestine radius is
0.18cm (0.1 that of human), so you can calculate the surface area for
any length of intestine....
Parvin
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The following message was posted to: PharmPK
Rat Intestine Surface Area ? What is the purpose of that one number?
Can a number be calculated as being characteristic for THE rat? The
size of the villi in regions of the small intestine varies
considerably with age, vitamin D status; the colon has only crypts.
The composition of the surface epithelium varies. Is it reasonable to
lump the intestine? Can data be meaningful that are calculated on the
basis of The Surface Area oF THE INTESTINE?
Walter E Stumpf
University of North Carolina
2612 Damascus Church Rd
Chapel Hill, NC 27516
www.walterstumpf.com
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The following message was posted to: PharmPK
Walter,
Variations in biological/physiological parameters are what we live with.
Averages and distributions can be estimated that provide useful starting
points for PK/PD and PBPK/PD analysis. The goal is not perfection, but
models that are adequate to guide project decisions in pharmaceutical
research and development. In sensitivity studies, it is often
surprising how
insensitive some parameters turn out to be . . . and then there are
those
showing significant sensitivity, which gives us a clue for where to look
when PK results are not consistent among subjects.
I know that you know all of this. So I suspect your comment comes from
the
perspective of treating individual patients. Then the imaging
technologies
in your area of expertise offer a level of precision that cannot be
matched
via modeling and simulation using averages. Nonetheless, when the goal
is to
design for a population, averages and distributions serve a valuable
purpose.
For rat, which for a given species raised in a given environment will
have
less variation, the averages and CV's are likely much more
representative
than for any reasonably sized human population.
Best regards,
Walt
Walt Woltosz
Chairman & CEO
Simulations Plus, Inc. (NASDAQ: SLP)
42505 10th Street West
Lancaster, CA 93534-7059
U.S.A.
http://www.simulations-plus.com
E-mail: walt.-at-.simulations-plus.com
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