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Show 123 school of medicine and health sciences The early embryonic heart changes from a simple cardiac tube to a functional four-chambered organ. Malformations in the heart structure are adversely affected by abnormal blood flow. We hypothesized that redistributing the intracardiac flow by experimental manipulations would result in the remodel-ing of the arterial wall. One way to perturb this system is by manipulating the preload, the state of the heart before pumping out the blood. We changed the preload by tying the left atrium, restrict-ing the blood flow through the atrium to left ventricle. White Leghorn chicken eggs were incubated at 38.5°C to stage-21 (3½-d). Using a 10-0 nylon suture, the left atrioventricular canal was ligated with an overhand knot. Intracardiac flow patterns were recorded at 60 Hz using a high speed digital camera attached to the stereophotomicroscope and a 2.93 GHz computer. A bolus of 10-nl Fast Green diluted in phosphate-buffer (0.28 mg/100 ml) was injected through the second bifurcation of the right vitelline vein at stage-21 (n = 13) immediately after the ligation, and at stage-24 (4-d, n = 10). We also recorded blood flow in normal stage-21 (n = 11) and stage-24 (n = 10) embryos. Data are analyzed by Fisher Exact test. In normal embryos, blood flow emerged primarily in the 4th aortic arches, followed by the 3rd, and then the 6th arches. 46.2% of the ligated embryos showed blood flowing dominantly through the 3rd aortic arches rather than the 4th as in normal stage-21 embryos. The sequence of the altered blood flow pattern increased to 50.0% as the ligated embryos developed to stage-24. Altered growth caused by altering flow patterns may result secondary to abnormal aortic arch development. These factors are important in the understanding of myocardial defects such as coarctation of the aorta, aortic stenosis and interrupted aortic arch. BLOOD FLOW PATTERN AND DISTRIBUTION OF THE AORTIC ARCHES IN THE LEFT ATRIAL LIGATED CHICK EMBRYO Kevin F. Lawrence, William H. Bowers, (Norman Hu, David A. Bull) Division of Cardiothoracic Surgery, Department of Surgery; and Department of Pediatrics, University of Utah Colorado College, Colorado Springs, CO UNDERGRADUATE RESEARCH ABSTRACTS Kevin F. Lawrence Norman Hu |
