General Frequently asked Questions
1. How do I prepare the microspheres before injecting them?
Answer: IMT packages the microspheres in
0.9% saline solution with 0.05% tween and 0.01% thimerosol. The tween is in the
saline to prevent aggregation of microspheres in solution. (Aggregation can cause
the microspheres to not evenly mix with the blood during injection a skew RBF results.)
The thimerosol is a bacteriostat used to prevent bacterial growth in the vials. The
microspheres can be centrifuged and re suspended in any saline solution as long as a
minimum of 0.01% tween concentration is maintained. As to why you would reduce
amount of tween in the microspheres I refer you to an study that tested the
injection of differing concentration of tween. Some animals are more sensitive to
the tween than others. Once the microspheres are suspended in the desired solution
the should be prepared for injection the following way.
- Invert the vial or tube slowly to distribute the microspheres evenly
- Sonicate the microspheres (recommended)
- Maintain inversion of the microspheres in the vial until they are loaded into the
syringe for injection. (Note: If cardiac output is to be determined, it is
important at this time to accurately sample the injection solution to determine the exact
concentration of the solution of microspheres you are injecting.) Inject the
microspheres followed by another injection of saline to rinse the microspheres out of the
syringe and or injection tubing used.
2. How many microspheres do I inject?
Answer: This answer has is different
many different answers depending on what animal and tissues types your looking at. I
will make some general comment and state some formulas that may help in adjusting the
amount to obtain statistically significant results.
Generally, the amount is determined by weight. Large
animals, such as sheep or pigs, will require at least 5 million per injection.
Medium size animals, such as dogs, will require 1 to 5 million microspheres per
injection. The actual number of micrspheres used should be determined by experiment
and or duplicating previous studies of similar nature.
3. Do vital stains or preservatives like formaldehyde affect the results?
Answer: No, there are processing
protocols to accommodate vital stains and preservatives.
4. What should I do when I find a white layer of fat on the surface of a sample
or have a sample that is gel like after the digestion of the tissue sample and the
addition of TBDRII.?
Answer: Re-heat the sample and transfer
it to a larger tube or split the sample into two tubes which will be combined later. Call
for details.
6. Is it possible to use EZ-Trac or Triton or Molecular probe microspheres with
the IPS service?
Answer: No. Possibly in the future.
7. Is it possible to analyze bone samples?
Answer: Yes, but processing time may take longer due
to extra decalcifying steps. Inquire for the protocol.
|
