We examined the myogenic response to infarction in neonatal and adult mice to determine the role of c-kit + cardiovascular precursor cells (CPC) that are known to be present in early heart development. Infarction of postnatal day 1–3 c-kit BAC -EGFP mouse hearts induced the localized expansion of (c-kit)EGFP + cells within the infarct, expression of the c-kit and Nkx2.5 mRNA, myogenesis, and partial regeneration of the infarction, with (c-kit)EGFP + cells adopting myogenic and vascular fates. Conversely, infarction of adult mice resulted in a modest induction of (c-kit)EGFP + cells within the infarct, which did not express Nkx2.5 or undergo myogenic differentiation, but adopted a vascular fate within the infarction, indicating a lack of authentic CPC. Explantation of infarcted neonatal and adult heart tissue to scid mice, and adoptive transfer of labeled bone marrow, confirmed the cardiac source of myogenic (neonate) and angiogenic (neonate and adult) cells. FACS-purified (c-kit)EGFP + /(αMHC)mCherry − (noncardiac) cells from microdissected infarcts within 6 h of infarction underwent cardiac differentiation, forming spontaneously beating myocytes in vitro; cre/LoxP fate mapping identified a noncardiac population of (c-kit)EGFP + myocytes within infarctions, indicating that the induction of undifferentiated precursors contributes to localized myogenesis. Thus, adult postinfarct myogenic failure is likely not due to a context-dependent restriction of precursor differentiation, and c-kit induction following injury of the adult heart does not define precursor status.

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In medium- to large-breed dogs, short-term outcomes for dogs that underwent VATS for lung lobectomy were comparable to those of dogs that underwent OT. Further studies are required to evaluate the effects of surgical approach on indices of postoperative pain and long-term outcomes.

Complete shunt occlusion after AC placement is usually dependent on soft tissue reaction. Ameroid constrictors ≥5 mm diameter may not promote complete shunt occlusion.

Results suggested that in dogs with right atrial hemangiosarcoma, surgical resection of the tumor was associated with a low complication rate and complications that did arise typically were minor. In addition, use of adjuvant chemotherapy following resection was associated with significantly longer survival times, compared with resection alone.