Electrophoretic and computer analysis of skeletal muscle used for cardiac assistance

Abstract

Skeletal muscle has an inherent plasticity which allows it to undergo fibre type transformation when induced by a specific stimulus. Electrical stimulation has been used here to induce transformation of a predominantly fast type skeletal muscle towards a slow, more fatigue-resistant phenotype, which is more suitable for use in long-term cardiac assistance. Muscle samples from animals electrically stimulated for periods up to 6 months have been analysed by electrophoresis for myosin heavy chain (MHC) and myosin light chain (MLC) fast and slow isoforms. Densitometry and computer analysis have been used to determine the pattern of transformation of the different myosin subunits over this time period. MHC and MLC 2 fast to slow isoform switching preceded that of the alkali light chains (MLC1 and MLC3). After 3 months of stimulation the MHC slow isoform was found to have doubled in concentration relative to the unstimulated control muscle and by 4 months accounted for almost 50% of the total MHC content. The slow isoform accounted for 75% of the MLC2 after 4 months of stimulation. The protein products of mRNA isolated from stimulated muscle samples, translated in vitro and separated by electrophoresis, showed that transformation at the mRNA level preceded that at the protein level. By 2-4 weeks of stimulation MLC2 slow isoform mRNA represented over 60% of the total MLC2 mRNA population. An understanding of the molecular structure of muscle during transformation provides insight into its haemodynamic performance in cardiac assistance.

Rapid high resolution two‐dimensional electrophoresis of human sperm proteins

“…The minigel format was the major factor in reducing processing time. Although other investigators have endeavored to improve protein separation by employing gels as large as 21 cm, the resolution obtained with the 8 X 7 cm gels employed in this study was very satisfactory [8]. Commercially available silver stains provided excellent results in 1 h. The practicality of this technique is underscored by the ability of a single operator to process multiple gels within a single day This rapid high-resolution 2-D PAGE technique for human sperm proteins may be useful for a variety of applications.…”