Radiation-induced Hemorrhagic Diathesis in Dogs Unassociated with Thrombocytopenia: Association with an Intravascular Protein-Polysaccharide Particle

1. Significant thrombocytopenia is not present preterminally in dogs given appropriate doses of Y⁹⁰-DTPA irradiation. Nevertheless, these animals have a severe hemorrhagic diathesis at postmortem examination.

2. Dogs systemically irradiated with Y⁹⁰-DTPA, and having a terminal hemorrhagic diathesis, demonstrate an intravascular polysaccharide substance at postmortem examination. This polysaccharide has staining characteristics similar to those first reported by Andersen in dogs systemically irradiated with x-rays, and more recently observed in the lesions of thrombotic thrombocytopenic purpura.