Search PubMed⌕ Search

Biomedical subjects

R N Cooper

Publications and source records attributed to R N Cooper.

6 recordsLinked to original sources
PubMed1999

In vivo satellite cell activation via Myf5 and MyoD in regenerating mouse skeletal muscle.

Regeneration of adult skeletal muscle is an asynchronous process requiring the activation, proliferation and fusion of satellite cells, to form new muscle fibres. This study was designed to determine the pattern of expression in vivo of the two myogenic regulatory factors, Myf5 and MyoD during this process. Cardiotoxin was used to induce regeneration in the gastrocnemius and soleus muscles of heterozygous Myf5-nlacZ mice, and the muscles were assayed for the presence of (beta)-galactosidase (Myf5) and MyoD. Adult satellite cells identified by M-cadherin labelling, when activated, initially express either MyoD or Myf5 or both myogenic factors. Subsequently all proliferating myoblasts express MyoD and part of the population is (beta)-galactosidase (Myf5) positive. Furthermore, we demonstrate that activated satellite cells, which express either Myf5 or MyoD, do not accumulate selectively on fast or slow muscle fibres.

Animals↗
PubMed1996

Intraspinal injection of embryonic neurons maintains muscle phenotype in adult chronic spinal rats.

A suspension of monoaminergic embryonic neurons was transplanted into the spinal cord of paraplegic rats. Enzyme histochemical, morphometric, and biochemical analyses of the hindlimb musculature were carried out 2-5 months later to determine the consequences on muscle atrophy and muscle phenotypes which were compared in three groups of rats: intact, spinalized, and spinalized and transplanted with embryonic cells. Our results indicate that this transplantation does not prevent muscular atrophy, which appears highly dependent on the level of muscular activity, but partially maintains the slow phenotype, especially in the soleus muscle. We conclude that fiber phenotypes are not determined by the level of muscular activity alone but are also dependent on putative trophic factors synthesized by motoneurones.

Animals↗