[Persorption of microparticles]

Solid, hard microparticles, such as starch granules, pollen, cellulose particles, fibres and crystals, whose diameters are well into the micrometre range, are incorporated regularly and in considerable numbers from the digestive tract. Motor factors play an important part in the paracellular penetration of the epithelial cell layer. From the subepithelial region the microparticles are transported away via lymph and blood vessels. They can be detected in body fluids using simple methods: only a few minutes after oral administration they can be found in the peripheral blood-stream. We observed their passage into urine, bile, cerebrospinal fluid, the alveolar lumen, the peritoneal cavity, breast milk, and transplacentally into the fetal blood-stream. Since persorbed microparticles can embolise small vessels, this touches on microangiological problems, especially in the region of the CNS. The long-term deposit of embolising microparticles which consist of potential allergens or contaminants, or which are carriers of contaminants, is of immunological and environmental-technical importance. Numerous ready-made foodstuffs contain large quantities of microparticles capable of persorption.