Tympanic bullae ultrasonography is feasible in nonsedated healthy rabbits (Oryctolagus cuniculus).

OBJECTIVE: To assess the feasibility of ultrasonography of the tympanic bullae (TB) in live, nonsedated rabbits (Oryctolagus cuniculus). ANIMALS: 40 healthy rabbits undergoing TB ultrasonography without sedation between September 2021 and May 2022. PROCEDURES: For each rabbit, fur was clipped over an area (3 X 3 cm) at the level of the angular process of each mandible, then 3 ultrasonographic planes of each TB were imaged via ventral approach, with measurement of the time taken to complete the examination. Three items were assessed for each plane: TB depth, wall integrity, and contents (present or absent). Results were compared for rabbits grouped as standard-sized breed type versus dwarf-sized breed type. RESULTS: The examination could be carried out successfully in 36 of 40 (90%) of rabbits with clipping. The restraint and examination were relatively well tolerated by the animals, except for the transverse sections. Obtaining oblique and longitudinal sections, carried out on 33 of 40 (83%) rabbits in our study, allowed for evaluation of the TB. The examination was feasible with all rabbit sizes. The depth of the TB was found to be linked to the size of the rabbit and especially to the size of its jaw. Visualization of the distal bulla wall was observed in 2 of the 40 (5%) subjects, consistent with abnormal fluid contents or bulla osteitis. CLINICAL RELEVANCE: Ultrasonography of the TB was easy to learn and rapid to perform, with a mean examination time of < 10 minutes (mean of 8.71 minutes) without any sedation.

Cell distribution after intracoronary bone marrow stem cell delivery in damaged and undamaged myocardium: implications for clinical trials.

INTRODUCTION: Early randomized clinical trials of autologous bone marrow cardiac stem cell therapy have reported contradictory results highlighting the need for a better evaluation of protocol designs. This study was designed to quantify and compare whole body and heart cell distribution after intracoronary or peripheral intravenous injection of autologous bone marrow mononuclear cells in a porcine acute myocardial infarction model with late reperfusion. METHODS: Myocardial infarction was induced using balloon inflation in the left coronary artery in domestic pigs. At seven days post-myocardial infarction, 1 x 10(8) autologous bone marrow mononuclear cells were labeled with fluorescent marker and/or 99mTc radiotracer, and delivered using intracoronary or peripheral intravenous injection (leg vein). RESULTS: Scintigraphic analyses and Upsilon-emission radioactivity counting of harvested organs showed a significant cell fraction retained within the heart after intracoronary injection (6 +/- 1.7% of injected radioactivity at 24 hours), whereas following peripheral intravenous cell injection, no cardiac homing was observed at 24 hours and cells were mainly detected within the lungs. Importantly, no difference was observed in the percentage of retained cells within the myocardium in the presence or absence of myocardial infarction. Histological evaluation did not show arterial occlusion in both animal groups and confirmed the presence of bone marrow mononuclear cells within the injected myocardium area. CONCLUSIONS: Intravenous bone marrow mononuclear cell injection was ineffective to target myocardium. Myocardial cell distribution following intracoronary injection did not depend on myocardial infarction presence, a factor that could be useful for cardiac cell therapy in patients with chronic heart failure of non-ischemic origin or with ischemic myocardium without myocardial infarction.