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Dear All,
My work mainly involves intestinal and hepatic perfusion experiments in
rats. Its given in the literature that preparations without suitable
oxygen carrier in the vascular perfusate will not maintain the
functional and structural integrity of liver. In order to maintain the
same, people use RBC containing perfusion media as one of the
alternative and for that, red blood cells are collected from various
sources such as human, bovine or from other rats.
My doubt is
When RBC derived from foreign sources are injected into rat
system,won't there be any antigen-antibody reaction. If such a reaction
is not existing, can anybody cite suitable reason for that.
Regards,
Ravi Kanth
Ravi Kanth Bhamidipati
PhD Student
Victorian College of Pharmacy
Monash University
381. Royal Parade
Melbourne
Dear Ravi,Back to the Top
My work sometimes involves hepatic perfusion and I use carbooxygene (95
%
O2, 5% CO2) to maintain the functional and the structural integrity of
liver. I start oxygenating the chelating, perfusion and digestion media
30
mintes before and also during the perfusion process.
It an easy way to avoid any antigen-antibody reaction, if there are any
(I
guess there are!).
Regards,
Monica Rigo.
Monica RIGO
GlaxoSmithKline
Psychiatry CEDD DMPK
Verona ITALY
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Dear Monica and Ravi,
There are many different types of oxygen carrying blood substitutes
that would do just fine. As far as the immunological reactions, this
would only be an issue of the mice had previously seen these antigens
in the past. If these are not whole RBCs, but rather a purified bovine
hemoglobin blood substitute (such as Oxyglobin®, a hemoglobin
glutamer. Another product, HBOC-201 is currently undergoing phase 1
and 2 testing. Oxyglobin® is a dark purple, sterile, polyionic
colloidal fluid, pH 7.8, based on glutaraldehyde-polymerized,
ultrapurified bovine hemoglobin formulated in a modified lactated
Ringer’s solution. It contains 13 g/dl of hemoglobin with a P50
of 35
mmHg; the P50 for normal dog hemoglobin is 26 mmHg. The oncotic
pressure of Oxyglobin® is similar to that of 5% albumin while the
osmolality is similar to that of normal plasma. Polymerization of the
bovine hemoglobin tetramer maintains a molecular weight mainly between
65 and 130 kD; this is important in order to prevent breakdown and
excretion of hemoglobin dimers with their subsequent renal toxicity. A
major advantage of cell-free hemoglobin solutions such as
Oxyglobin® is
that they lack the antigenic red cell stroma present in whole blood and
thus do not require crossmatching prior to infusion. Oxyglobin® is
approved by the FDA for treating canine anemia.
Other investigators have used this quite successfully for many
different species, with not problems with immune reactions. I have
used this, and have had no issues.
Best Regards,
Russell Higbee
Russell G. Higbee, MS, PhD, DVM
Senior Scientist
VaxDesign Corporation
2721 Discovery Drive
Orlando, FL 32826
407-249-3658
407-249-3649 (fax)
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Dear Monica,
About the work using carbooxygene (95% O2, 5% CO2) to maintain the
functional
and the structural integrity of liver. I would like to know what the
carbooxygene flow rate is and if there is any effect of the flow rate
change on
the PK behavior of liver or other organs. Thank you.
Regards,
Shanjun
University of Toronto
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Dear Shanjun,
Around 2 bars in 500 mL of medim for 30 minutes it will be sufficient.
It
is not important the precision of the flow rate (it of course depends on
the volume you are oxygenating): from my experience it doesn't make any
difference.
It is important to monitore the pH during this opreation. For this
purpose
I always use madia added with phenol red.
I'm speaking only about livers as I've never perfused other organs.
Best regards,
Monica.
Monica RIGO
GlaxoSmithKline
Psychiatry CEDD DMPK
Verona ITALY
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Monica RIGO wrote:
> I always use media added with phenol red.
Monica,
That might be a bit worrisome as phenol red has been shown to be a
substrate for drug transporters (albeit those predominantly expressed
in the kidney) so you might see interference in your studies.
Have a look at Itagaki et al. (2003) Eur. J. Pharmacol. 475, 85-92.
There's also the known oestrogenic activity of contaminants common in
commercial preparations of phenol red, although this is unlikely to be
of great relevance in most organ perfusion studies.
All the very best,
Bernard
--
Bernard Murray, Ph.D.
Senior Research Investigator
Drug Metabolism, PCS, PPD, GPRD, Abbott Laboratories, Chicago, USA
Bernard.Murray.at.abbott.com
I know it is a while since this question was posted but as far as I knowBack to the Top
rats do not have blood group antigens on their red cells as do dogs and
humans. It is therefore not a problem to inject blood from one rat to
another in terms of antigen-antibody reactions.
Rat blood (diluted in albumin solution) is commonly used for perfusion
experiments in rat organs and rat blood can be used to measure the
half-life of red blood cells by labelling donor red cells with
radioactive chromium and then injecting them into recipient rats.
Hope these comments are helpful.
Regards,
Nick Kerwin
Head In-Vivo Discovery
BioDynamics Research
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