Fibre size, atrophy, and hypertrophy factors in vastus lateralis muscle from 18- to 29-year-old men.
In order to study the size of muscle fibres, cross-sections of autopsied vastus lateralis muscle from 8 healthy men, aged 18 to 29 years, who have died suddenly were prepared and analyzed. Data were obtained on cross-sectional area, on lesser diameter, and on atrophy and hypertrophy factors of type 1 and type 2 fibres, subdivided into 2a, 2b, and 2c fibres. The difference in mean fibre size between type 1 and 2 fibres was not significant, whereas the differences between type 1 and 2b, type 1 and 2a, and type 2a and 2b fibres were significant. In the whole material type 2a fibres were the largest and type 2b fibres the smallest. There were considerable differences between post-mortem subjects. Because of these differences and the variability of all fibre types in respect of size in a sample the normal ranges of fibre size were large. The normal ranges and a continuous scale of weights were used to determine the atrophy and hypertrophy factors in each sample, and the upper limits of these factors accepted as being normal. The estimates of the limits of normality of the area, diameter, atrophy and hypertrophy factors of type 1, 2, 2a and 2b fibres reflect the situation in the vastus lateralis muscle of healthy young men. These values might be useful in studying physiological and pathological conditions influencing the size of different fibre types.
Pernus
F
F
Faculty of Electrical and Computer Engineering, University of Ljubljana, Slovenia.
Erzen
I
I
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000375:Aging / Q000473:pathology; D006651:Histocytochemistry; D006801:Humans; D006984:Hypertrophy; D008297:Male; D009132:Muscles / Q000166:cytology / Q000294:innervation / Q000473:pathology*; D009133:Muscular Atrophy / Q000473:pathology*; D009412:Nerve Fibers / Q000648:ultrastructure*; D012016:Reference Values
D000251:Adenosine Triphosphatases