EFFECTS OF EXTRACORPOREAL ULTRASOUND SHOC K-WAVES ON LATE EMBRYOS OF THE TELEOST ORYZIAS-LATIPES

Exposure to low-energy ultrasound shock waves (1000 impulses at a freq uency of 2/sec and an energy density of 0.08 mJ/mm(2); peak positive/n egative pressure 16/-7 MPa; pulse duration about 10 mu sec) led to the following alterations in the cells and tissues of stage 35 embryos of Oryzias latipes ranked according to their extent: (1) In various tiss ues, especially in the trunk musculature, orthodox mitochondria were t ransformed into condensed (=low energy) mitochondria. (2) Nuclear enve lopes and sarcoplasmatic reticulum of muscle fibres as well as endopla smatic reticulum of epidermal ionocytes were often vesicularly dilated . (3) Muscle fibres in the trunk musculature began to separate from ea ch other. Epidermal intercellular spaces were enlarged and increased i n number. (4) Destruction of vessels and haematomas were observed in t he circulatory system of the yolk sac. (5) Necroses up to total disint egration were found in various organs of the body cavity (intestine, l iver, spleen). The less serious alterations (1 and 2) occurred in orga ns completely surrounded by other tissues. Major damages (4 and 5), ho wever, affected only organs with free outer and inner surfaces, probab ly explained by cavitation and jet stream phenomena within the adjacen t fluids.