The plasma cortisol level of patients anaesthetized for 1 hour with thiopentone and nitrous oxide was found to remain unchanged. During body surface surgery it rose slightly, and during intra-abdominal surgery it rose to more thap double the resting value. The blood sugar under the same circumstances changed in a qualitatively similar manner and the free fatty acids appeared to fall during anaesthesia without surgery, changed litde during body surface surgery, and rose during intra-abdominal surgery. Plasma insulin during both types of surgery showed no significant change.
Calcium homeostasis is altered by strenuous physical exercise. The mechanism is unclear. Our study was designed to investigate this relationship, particularly any associated changes in the calcium regulating hormones. Six subjects carried out a strenuous exercise programme for 10 min on a bicycle ergometer. Blood samples were analysed for ionized calcium, total calcium, calcitonin and pH. Plasma parathormone was assayed using a new and very sensitive N-terminal assay. Serum ionized calcium was significantly elevated by exercise at 50% of maximum aerobic capacity (VO2 max). The rise persisted until the late recovery phase, when it fell significantly below resting levels. Plasma parathormone levels were initially depressed by moderate exercise (50% VO2 max.) but were significantly elevated during and immediately after severe exercise. Our results suggest that exercise stimulates the hormonal, osteolytic influences acting on the skeleton, with increases in plasma parathormone and mobilisation of calcium stores. These changes may provide a supply of raw material allowing the osteogenic mechanical forces initiated by exercise to produce a positive skeletal balance. In view of the possible relevance of these findings to the understanding and management of osteoporosis we feel that this area merits further study.
SYNOPSIS In two families with severe sex-linked muscular dystrophy, high levels of ct-hydroxybutyrate dehydrogenase (HBD), lactate dehydrogenase (LD), aspartate transaminase (AspT), aldolase, and creatine phosphokinase (CPK) were found in the sera of three young affected males. In both families the mother had a raised level of HBD activity. Four sisters of the three affected boys had raised serum enzyme levels, and they are regarded as presumptive carriers of the disease. Biopsy specimens of dystrophic muscle had LD and HBD contents which were significantly lower than those of control specimens, while the HBD/LD ratios were markedly greater. Muscle from two unaffected members of the same family also exhibited high ratios, indicating the presence of the electrophoretically fast LD isoenzymes, and this was confirmed by acrylamide-gel electrophoresis.Measurement of the serum a-hydroxybutyrate dehydrogenase activity has provided a convenient means for the detection of a relative increase in the electrophoretically fast-migrating lactate dehydrogenase isoenzymes, LD1 and LD2 (Rosalki and Wilkinson, 1960;Plummer, Elliott, Cooke, and Wilkinson, 1963), and has proved to be a useful diagnostic test in myocardial infarction and other conditions in which LD1 and LD2 are released into the circulation (Elliott and Wilkinson, 1961; Konttinen, 1961;Pagliaro and Notarbartolo, 1961;Rosalki, 1963 and glutamic-pyruvic transaminase (SGOT and SGPT), aldolase and creatine phosphokinase (CPK) levels were also determined since abnormal activity of these enzymes in the serum is known to occur in progressive muscular dystrophy (Sibley and
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