Rmv 707b

Non-invasive metrics of cardiopulmonary function were measured using echocardiography procedures as previously described^{5 (link)} at 10, 14, and approximately 18 weeks of age, which correspond to 6, 10, and 14 weeks, respectively, after tamoxifen treatment to activate the transgene. Measurements were made at these time points to examine whether adverse cardiovascular events were evident at or before the duration of Bmp1 and Tll1 ablation where defects were previously observed in other tissues. Measurements were performed on an additional 10 female mice (n=5 controls; n=5 BT^KO) at 26, 30, and 34 weeks of age to examine whether adverse phenotypes would occur with longer durations of Bmp1 and Tll1 ablation. Briefly, mice were anesthetized with isoflurane (1%) while body temperature was maintained at 37ºC using a heated pad. A 30-MHz transducer (RMV 707B, Visual Sonics, Toronto) was used to obtain 2D guided M-mode and Doppler images in the left and right ventricles (LV and RV, respectively). RV wall thickness, mitral (MVE, MVA) and tricuspid (TVE, TVA) valve velocities in early and late diastole, fractional shortening (FS), and aorta (Ao) and pulmonary artery (PA) diameters and ejection times (ET) were determined from images acquired over at least three consecutive heartbeats. LV wall thickness was estimated using LV dimensions in diastole as previously reported ^{5 (link)}.

Body weight (BW) was measured, and then mice were anesthetized with isofluorane (1%) and maintained at 37°C via a heated platform. Transthoracic echocardiography was performed with a 30-MHz transducer (RMV 707B, Visual Sonics, Toronto) (Brody et al., 2012 (link); Harris et al., 2002 (link)). Two-dimensionally guided M-mode and Doppler images were acquired at the tip of the papillary muscles in the left ventricle (LV) to assess ventricular function. From these images, LV and septum (S) mass was estimated (LV_iv+S, in vivo) and the common carotid artery blood flow velocity and length were measured. Diastolic function was assessed by isovolumic relaxation time (IVRT). Systolic function was evaluated by endocardial fractional shortening (%FS). All parameters were obtained over at least three consecutive heartbeats.