Biomedical subjects
Publications and source records attributed to J Rutkiewicz.
Activity of 5'-nucleotidase was shown to be higher in the slow-twitch muscle than in the fast-twitch oxidative-glycolytic muscle and in the latter it was higher than that in the fast-twitch glycolytic muscle of the rat. Both denervation and tenotomy resulted in marked elevation of the enzyme activity in each muscle type.
Adenosine deaminase activity was shown to decrease in each skeletal muscle type (the slow-twitch oxydative, fast-twitch oxydative--glycolytic and fast-twitch glycolytic) at the beginning of exercise of moderate intensity and to return to the control when exercise was continued till exhaustion. 5 min occlusion of the femoral artery had no effect on the enzyme activity in either muscle. The reduction of the enzyme activity at the onset of exercise could result in reduction of adenosine breakdown and thus contribute to vasodilation at this stage of increased contractile activity of the muscles.
Adenosine deaminase activity was studied in the gastric mucosa of patients with peptic ulcer in relation to ulcer localisation and treatment with ranitidine or sucralfate. Enzyme activities observed in the corpus mucosa were higher at a distance of over 2 cm from the ulcer margin than that recorded close to the ulcer. A significant decrease in adenosine deaminase activity was found after treatment with ranitidine but not with sucralfate. In the antral mucosa, enzyme activity was constant in all the groups observed. The evaluation of adenosine deaminase activity in gastric mucosa can be useful for studies of pathologic changes in the stomach.
This study aimed to examine the extent to which repletion of glycogen in muscles partially depleted of glycogen may be inhibited by contractions and epinephrine. Four experiments were carried out on untrained male Wistar rats. 1) Animals ran 150 min (1,200 m/h) on a treadmill set at +10 degrees incline. After 60, 90, and 120 min of running, they were given glucose (40% solution, 1 ml/100 g) by a stomach tube. 2) Rats ran on a treadmill set as above for 20 min at 3,200 m/h and then 2 h at 800 m/h. 3) In anesthetized rats, gastrocnemius-plantaris muscle group was made to contract isometrically by means of stimulation of the sciatic nerve. The nerve was stimulated with tetanic pulses (7 V, 0.05-ms duration, delivered in 100-ms trains at 100 Hz): first 15 min, 2 pulses/s, then 2 h, 1 pulse/2 s. 4) Epinephrine (0.5 mg/kg) was administered subcutaneously 10 min before onset of stimulation of the sciatic nerve. The nerve was stimulated 15 min with tetanic pulses (as above), 2 pulses/s. Next, rats were rested for 2 h. Level of glycogen was determined in samples of white and red gastrocnemius, plantaris, and soleus. Initial running or stimulation resulted in pronounced glycogen depletion in each muscle. Thereafter, either considerable or full repletion of glycogen occurred in the muscles despite continued contractile activity or the presence of epinephrine. The degree of repletion depended both on the type of muscle and the type of activation of glycogenolysis (running, stimulation of the nerve, epinephrine).(ABSTRACT TRUNCATED AT 250 WORDS)
After administration of insulin adenosine deaminase activity was reduced in different skeletal muscle types, the heart and the liver. On the other hand profound reduction in the plasma insulin concentration (streptozotocin diabetes) resulted in elevation of the enzyme activity in the tissues. It is concluded that the local concentration of adenosine may be effected by the concentration of insulin in the plasma.
In the rat, muscle glycogen is mobilized during the first stage of exercise, despite normoglycaemia. The aim of the present study was to examine if this process could be prevented or reduced by hyperglycaemia. Three experiments were carried out: in the first, rats were forced to run on a treadmill; in the second the gastrocnemius muscle group was made to contract by stimulation of the sciatic nerve and in the third adrenaline was administered subcutaneously. Each group was divided into two subgroups: control and enriched with glucose (hyperglycaemic). It was shown that hyperglycaemia has no effect on running-induced glycogen mobilization in hind-limb muscles of different fibre composition but prevented it totally in diaphragm muscle. Hyperglycaemia also did not affect the glycogen mobilization induced by stimulation of the sciatic nerve. However, it delayed and reduced markedly the glycogenolytic effect of adrenaline. It is concluded that increased glycogenolysis in muscles at the beginning of exercise may be a consequence of a delay in the activation of glucose transporting mechanisms in muscle cells.
Adenosine deaminase (ADA) activity was estimated in human gastric mucosal specimens taken endoscopically. Three groups of patients were studied: 6 subjects with achlorhydria, 11 patients with normal gastric acid secretion and 6 patients with hypersecretion. The activity of ADA in mucosal homogenates was measured by determination of the ammonia liberated from the substrate. It was found that in the subjects with normal or increased gastric acid secretion, ADA activities were higher in specimens taken from the gastric fundus than in slices coming from the antral region. In the fundic mucosa the highest ADA activity was noted in patients with hypersecretion. Moreover, in this gastric region a positive correlation between ADA activity and basal or maximal acid output values was found. It is concluded that ADA might be involved in the regulatory system of gastric acid secretion.
Activities of alanine and aspartate aminotransferase in different muscle types and in the liver of streptozotocin diabetic rats were studied 1,2 and 3 days after administering of streptozotocin. It was shown that the activity of both enzymes was elevated in the "white" layer of the vastus lateralis, in the liver and in the heart, whereas it remained unchanged in the "red" layer of the same muscle, in the soleus and the diaphragm. It is concluded that the effect of acute insulin deficiency on the aminotransferase activity in skeletal muscles depends on the muscle fiber composition and does not appear in muscles with a high oxidative potential. These results indicate that muscle fiber composition should be taken into account when evaluating the role of insulin in amino acid metabolism in the muscle.
The role of insulin in the control of triacyglycerol (TG) in different types of skeletal muscle has not been fully recognized so the aim of the present study was to fill this gap. The experiments were carried out on control rats, those fed with olive oil or fed with the oil and treated with insulin and on streptozotocin diabetic animals at rest and there after exercise till exhaustion. The level of TG was measured in the white and red layers of the vastus lateralis, the soleus and the diaphragm. It was found that acute feeding with olive oil had no effect on TG level in either muscle type examined. Insulin administered to rats fed with oil increased TG level in the red vastus. Streptozotocin diabetes caused an increase in TG level in muscles with high oxidative potential. Exercise lowered the level of TG only in the red vastus of the diabetic rats. It is concluded that insulin may increase muscle TG level. Accumulation of TG in muscles of rats with acute diabetes is likely to be a result of the high plasma free fatty acid concentration. Acute insulin deficiency did not affect the muscle TG response to exercise.
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