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Biomedical subjects

F M Hansen-Smith

Publications and source records attributed to F M Hansen-Smith.

23 records · Page 2Linked to original sources
PubMed1978

Comparison of the chemical and biochemical composition of thirteen muscles of the rat after dietary protein restriction.

1. The objective of this study was to determine whether the chemical and biochemical changes induced by muscle wasting caused by dietary protein restriction are different in various skeletal muscles. 2. Rats were fasted for 3 d and then fed on a 10 g protein/kg diet for 21 d. Thirteen muscles from the trunk, forelimb, and hind-limb regions were analysed for muscle weight, and the content of water, fat, cellular and extracellular protein, DNA and RNA. Results were compared to values for an 'initial' control group killed at the start of the experiment. 3. Weight loss was greatest in trunk muscles and least in the distal forelimb muscles. Water content decreased in most muscles, but increased in three forelimb muscles. A significant loss of lipid was found in the gastrocnemius, while the biceps brachii gained lipid. Changes in lipid content of the muscles did not form a distinctive pattern. 4. All muscles except the distal forelimb muscles lost a significant amount of cellular protein, while all muscles except the diaphragm gained extracellular protein. 5. DNA content was unchanged in all muscles. The value for cellular protein:DNA was significantly reduced in the rectus abdominis and the diaphragm. A significant loss of RNA was found in all muscles; the percentage change was greatest in trunk muscles and least in the distal forelimb muscles. The values for RNA:protein and RNA:DNA were significantly lower in all muscles except two distal forelimb muscles. 6. With the exception of the water and lipid content of the muscles, the directions of the changes in the experimental animals were the same for all muscles. The results suggested, however, that the magnitude of changes in certain chemical and biochemical indices of composition may depend to some extent on the anatomical location of the muscle: trunk muscles tended to show the greatest percentage change, while the distal forelimbs changed the least.

Animals↗
PubMed1978

Quantitative analysis of nuclear population in muscle from malnourished and recovered children.

Muscle tissue obtained by needle biopsy from the quadriceps femoris of eight malnourished and eight recovered children were examined histologically. In both groups about two-thirds of the total nuclear count was due to muscle nuclei. The remaining one-third was made up of vascular, nerve, and interstitial cells and isolated nuclei in similar proportions in the two groups. A significantly greater percentage of muscle nuclei consisted of myogenic cells in recovered children as compared to malnourished children (20.7 +/- 6.4 vs. 2.6 +/- 1.4%).

Blood Vessels↗
PubMed1977

Effect of dietary protein restriction or food restriction on oxygen consumption and mitochondrial distribution in cardiac and red and white skeletal muscle of rats.

The effects of food restriction and dietary protein restriction on the oxygen consumption of three types of muscle in the rat were compared. Control rats were fed a diet containing 27% casein. Two groups of protein-restricted rats were fed isoenergy diets containing 15% or 8% casein. Two groups of food-restricted rats were fed either the 27% or 15% casein diets in amounts equivalent to 35% of the intake of energy. Oxygen consumption was measured in papillary muscle and in fibers from the red (high oxidative) and white (low oxidative) portions of the quadriceps with pyruvate and malate as substrates. Control values (micronlO2/g dry wt/min) were 35.2 + 1.5 (papillary), 20.7+/-1.9 (red), and 7.8+/-0.7 (white). Restriction of dietary protein content failed to alter the oxygen consumption of any of the muscle types. In contrast, involuntary food restriction,combined with a reduction in protein content, caused a reduction in the oxygen consumption of papilary and white skeletal muscle, but the metabolism of red skeletal muscle was not affected. No differences were found in the appearance and distribution of mitochondria in cardiac or red skeletal muscle after examination by electron microscopy, but a depletion of subsarcolemmal mitochondria was evident in white muscle from the food-restricted rats.

Animals↗
PubMed1977

Influence of chronic undernutrition on oxygen consumption of rats during exercise.

Endurance swimming times and oxygen comsumption during strenuous exercise were measured in age-paired undernourished rats. The animals received restricted or unrestricted amounts of 27, 15 or 8% casein diets for 10 weeks. Endurance times of energy-restricted animals were similar to that of controls, despite a two-fold weight difference. Endurance time of the protein-restricted group (8% casein) was longer than that of any other group, including energy-restricted groups identical in weight. Oxygen consumption of the protein-restricted group during a non-endurance swim was significantly greater than any of the other groups, but was the same as that of the other undernourished groups during the endurance swin. Oxygen consumption by all undernourished groups was higher than that of controls during the endurance swim. Results of the endurance swimming tests show that restriction of protein or energy intake may influence exercise performance differently and that differences in work performance cannot be explained by differences in body weight. Measurements of oxygen consumption during swimming suggests that the differences in performance are related to altered metabolic requirements resulting from the dietary restrictions.

Animals↗