The cytological characteristics of two modes of muscle hypertrophy were studied in the extensor digitorum longus muscle of the rat. Comprensatory hypertrophy (CH) was produced by tenotomy of the tibialis anterior muscle and work-induced hypertrophy (WIH) was produced by forced swimming of the animal. While both methods produced an increase in muscle weight and cell size, these two parameters did not correlate. Morphometric analyses of the hypertrophied muscle cells demonstrated that in CH-muscle there was an increase in mitochondrial volume density, a decrease in myofibrillar volume density and no change in sarcotubular or nuclear volume density. WIH-muscle demonstrated an increase in sarcotubular volume density but no change in mitochondrial, myofibrillar or nuclear volume density. It is concluded that in CH-muscle, the cell volume increase is attributable to mitochondrial volume increase and that there is no increase in the contratile myofibrillar component of the cell. WIH-muscle, on the other hand, has a cell volume increase which is attributable to a proportional increase in these organelles.

A survey of U.S. departments of anatomy, physiology, and biochemistry shows that 39% of the respondent anatomy departments reported declines in the numbers of graduate students taking the human gross anatomy course. Similarly, 42% of the departments reported decreases in the numbers of graduate students teaching human gross anatomy. These decreases were greater in anatomy than in physiology and in biochemistry. The percentages of departments reporting increases in students taking or teaching their courses was 6% for human gross anatomy and 0% to 19% for physiology and biochemistry courses. To reverse this trend the establishment of specific programs for the training of gross anatomy teachers is advocated. These new teachers will be available as the need for them is increasingly recognized in the future.

We noted the earliest morphological changes in the motor endplates 8 weeks after the induction of streptozotocin diabetes in rats. Morphometric measurements showed reduced axonal areas of the lateral plantar and the sciatic nerves in the diabetic rats 28 but not 2 and 8 weeks after the experiment. These findings suggested distal axonopathy.

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