Surgical Registrars Prize Day

Methods: A first-generation adenoviral vector (1 X 1012 total viral particles) containing the human B2AR transgene (Adeno-B2AR; n=6), or phosphate buffered saline (PBS; n=6) was delivered to neonatal piglets through the proximal aorta, following aortic cross-clamp and cold crystalloid cardioplegia. Animals were recovered and 2 days later had a left ventricular micromanometer inserted under sedation to assess basal and isoprenaline (0.01 to 0.lI g.kg-1.min-') stimulated cardiac function prior to euthanasia. 13AR density was measured in left ventricle, liver and lung by radioligand binding. Statistical analysis was performed using Student's t-test, Mann-Whitney test and two way analysis of variance with repeated measures on one factor (ANOVA). Results: Left ventricular receptor density (fmol.mg-I membrane protein) was greater following Adeno-62AR compared to PBS (520±250.9 v 104±5.7; p<0.01). B adrenergic receptor density in liver (79±6.0 v 67+5.3; p=ns) and lung (250±16.3 v 260+22.2; p=ns) was similar between groups. Basal cardiac function was similar between groups. However, following isoprenaline infusion enhanced dP/dtmax(p=0.02), enhanced heart rate (p=0.0002), and reduced enddiastolic pressure (p<0.002) were observed in Adeno-B2AR treated animals, indicating increased cardiac function.