Implication of activation of intraperitoneal macrophages with bio-degradable microspheres.

To estimate the possibility that biological degradable starch microspheres (DMS) activate abdominal or intraperitoneal macrophages (IMP), two sizes of DMS (Spherex, Pharmacia, Sweden) were injected into the peritoneum of the ICR mice of 4 to 8 weeks of age. Three days after the injection, peritoneal fluid was collected and incubated for one hour at 37 degrees C under 5% CO2. The cells which adhered to the petri dish were IMP, to which DMS was added for 18 hrs.

Scanning and transmission electron microscopy of biodegradable microspheres (DSM) in blood vessels.

A type of biodegradable microsphere (DSM), approximately 45 microns in diameter, made of polymerized potato starch (Pharmacia, Sweden) was intravenously injected into rats to observe the state of DSM in small blood vessels in the kidney and liver at the electron microscopic level. Prior to their digestion with amylase, individual DSM changed their round shape to an irregularly folded one to occupy almost the whole area of the lumen. At the transmission electron microscopic level, DSM were impregnated with colloidal iron and were easily identified.