Cobalt-labeled dextran particles are effective radioactive microspheres for animal studies. These particles show minimal cobalt dissociation and no tissue reaction, validating their use for experiments lasting several hours.
Area of Science:
Biomedical Engineering
Radiochemistry
Materials Science
Background:
Radioactive microspheres are essential tools for studying physiological processes.
Dextran particles offer a suitable matrix for radioactive labeling.
Evaluating the stability and biocompatibility of labeled particles is crucial for experimental validity.
Purpose of the Study:
To prepare and characterize radioactive dextran microspheres for use in animal experiments.
To assess the labeling efficiency and stability of cobalt (57Co, 58Co) and iodine (131I) labels.
To evaluate the in vitro and in vivo behavior of these labeled particles, including dissociation and tissue interaction.
Main Methods:
Preparation of chelating dextran particles and Sephadex particles with specified diameters.
Radioactive labeling of particles using 57Co, 58Co, or 131I.
Determination of labeling efficiency and specific activity.
In vitro and in vivo assessment of label dissociation.
Microscopic evaluation of particle-induced tissue reactions after injection in animals.
Main Results:
High labeling efficiency (96.4%) achieved with 57Co or 58Co, compared to 7.8% with 131I.
Negligible cobalt label dissociation in vitro and low dissociation (0.4-0.7% per h) in vivo.
Significant dissociation of the iodine label both in vitro and in vivo.
15-micron cobalt-labeled particles remained entrapped in lungs for 35 days without microscopic changes or tissue reaction.
Conclusions:
Cobalt-labeled dextran particles are validated for use as radioactive microspheres in animal experiments lasting several hours due to their stability and biocompatibility.
Iodine-labeled particles are limited to experiments requiring a single determination of blood flow distribution due to label instability.
