Connexins in skeletal muscle development and disease.

Gap junctions consist of clusters of intercellular channels composed of connexins that connect adjacent cells and allow the exchange of small molecules. While the 21 member multi-gene family of connexins are ubiquitously found in humans, only Cx39, Cx40, Cx43 and Cx45 have been documented in developing myoblasts and injured adult skeletal muscle while healthy adult skeletal muscle is devoid of connexins. The use of gap junctional blockers and cultured myoblast cell lines have suggested that these connexins play a critical role in myotube formation and muscle regeneration.

Determining the minimum number of detectable cardiac-transplanted 111In-tropolone-labelled bone-marrow-derived mesenchymal stem cells by SPECT.

In this work, we determined the minimum number of detectable 111In-tropolone-labelled bone-marrow-derived stem cells from the maximum activity per cell which did not affect viability, proliferation and differentiation, and the minimum detectable activity (MDA) of 111In by SPECT. Canine bone marrow mesenchymal cells were isolated, cultured and expanded. A number of samples, each containing 5x10(6) cells, were labelled with 111In-tropolone from 0.

Embryonic and fetal rat myoblasts form different muscle fiber types in an ectopic in vivo environment.

Limb muscle development is characterized by the migration of muscle precursor cells from the somite followed by myoblast differentiation and the maturation of myotubes into distinct muscle fiber types. Previous in vitro experiments have suggested that rat limb myoblasts are composed of at least two distinct myoblast subpopulations that appear in the developing hindlimb at different developmental stages. These embryonic and fetal myoblast subpopulations are believed to generate primary and secondary myotubes, respectively.