HEMATOLOGIC AND GROWTH-RELATED EFFECTS OF FREQUENT PRENATAL ULTRASOUND EXPOSURE IN THE LONG-TAILED MACAQUE (MACACA-FASCICULARIS)

Prior investigations have shown that reduced birth weights and transie nt neutropenias result from frequent exposure of monkey fetuses to ult rasound. To further explore these findings, 26 animals were studied (1 6 exposed, 10 controls; ''triple mode''; ATL Ultramark 9 with HDI(R); I-SPTAd similar to 645 to 714 mW/cm(2)). Exposures were performed dail y for 5 days each week from gestational days (GD) 21 to 35 (5 min), th ree times weekly from GD 36 to 60 (5 min), then weekly from GD 61 to 1 53 +/- 1 (10 min). Fetal blood samples (FBS) were collected for comple te blood counts (CBCs), hematopoietic progenitor assay, circulating in sulin-like growth factors (IGF-I, IGF-II) and binding proteins (IGFBP- 3) (GD 120, 140, 153 +/- 1). Animals were delivered by Cesarean sectio n at term (GD 153 +/- 1), and body weights, morphometrics, CBCs, and b one marrow aspirates assessed at delivery and postnatally for 3 months . Fetal neutropenias were noted in exposed animals in addition to redu ced circulating progenitors (colony forming unit-granulocyte-macrophag e [CFU-GM]). Growth of CFU-GM from bone marrow was exuberant at term, whereas circulating levels were diminished comparable to prenatal samp les. Exposed animals were smaller at birth; marked reductions in IGFBP -3 were noted prenatally. These data suggest that frequent prenatal ul trasound exposure can transiently alter the neutrophil lineage, althou gh these findings may be the result of enhanced margination and organ sequestration. Data also suggest that transient, altered growth patter ns may be due to perturbations of the IGF axis.