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Biomedical subjects

G A Meek

Publications and source records attributed to G A Meek.

14 recordsLinked to original sources

Ultrastructure of muscle spindles in C57BL/6J dy2J/dy2J dystrophic mice.

The sensory organs of skeletal muscles, the muscle spindles, were examined using electron microscopy in dy2J/dy2J dystrophic mice. Despite widespread damage to the extrafusal (skeletomotor) fibres the intrafusal (spindle) fibres appeared normal and seemed resistant to the aetiological factors for murine dystrophy.

Animals↗

Stereological analyses of the structure of mitochondria in pigeon skeletal muscle.

The mitochondria in type-I and -II muscle fibres in the pectoralis major muscle of the pigeon (Columba livia) have been analysed using stereological techniques not previously applied in muscle biology. Mitochondrial volume fractions (VV) were estimated in different regions of each type of muscle fibre using randomly orientated sampling sectors within fibre profiles. These sectors were sub-divided into smaller sampling regions to provide accurate data on the intracellular distribution of mitochondria. Estimates of the external surface densities of mitochondria per unit volume of fibre, SV total surface, and also the densities of mitochondrial cristae, SV total cristae, were obtained using a specific technique derived for analysing anisotropic structures (Saltykov, 1958). The relative amounts of the random and orientated mitochondrial membranes were also estimated. Significant differences were found to exist between the different types of muscle fibres and considerable though constant variations in the intracellular arrangement of mitochondria were also found.

Animals↗

Changes in the activities of respiratory enzymes during the aerobic growth of yeast on different carbon sources.

1. Unlike yeast cells grown on glucose (0.9%), cells grown on galactose aerobically or anaerobically as well as cells grown on very low glucose concentrations (0.09%) have been found to possess mitochondria. 2. Synthesis of respiratory enzymes was less in the presence of glucose than galactose. When either sugar was consumed, synthesis of these enzymes increased. 3. A possible mechanism is suggested for the repression of mitochondrial formation by glucose by means of a ;high-energy' substance easily derived from glucose.

Journal Article↗