Measuring Black Carbon Particles in Human Placentae
PHILIP K. HOPKE, Atsuo Chiu, Verda Thomas, Emma Norris, Richard Miller,
University of Rochester School of Medicine and Dentistry Abstract Number: 657
Working Group: Health-Related Aerosols
AbstractExposure to ambient particulate matter (PM) and adverse birth effects including pre-term birth and low birth weight have been reported. Traffic Related Air Pollution (TRAP) is particularly important in inducing adverse effects. A useful indicator of TRAP is black carbon (BC) particles. Prior work reported finding BC particles in human placenta. Thus, translocation of ambient particles from the lungs to maternal blood to the placenta including the fetus may be an important pathway for toxicants that impair placental development and by extension, fetal growth. Tissue was examined using a two-photon laser microscope (Olympus FVMPE-RS) to provide a 3-dimensional image of the sample. BC particles were identified by the relatively uniform light emission across the 4 detection channels and physical diameter of ~ 0.3 µm. From the resulting images, the number of particles per unit volume of each sample were determined using Imaris image analysis (IIA). Initial work determined that formalin precipitation was not a problem, but typical histological stains did produce false positives. Thus, unstained tissue has been examined. Our design was to examine 60 views of a given placenta. Each image was screened using IIA and the computer-identified particles were further assessed manually to ensure that they met the criteria for identification as being BC. We have measured the particle numbers in 5 placentae. Typical numbers per view are 4.52 ± 3.66, 2.83 ± 2.48, and 2.60 ± 2.30, in the material blood, fetal tissue, and fetal blood, respectively. Converting these numbers to particle density (particles per unit volume), we obtained 11,450 ± 9,230, 7,220 ± 6,650, and 6,670 ± 5,920 particles per cubic millimeter for one particular placenta.
This work was supported in part by the RW and MS Goode Grant.
This abstract has supplementary material available. Click PDF icon to download.