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Some Problems of Myocardial Insufficiency in Toxo-Allergic Myocarditis |
M.
Rogava, N. Kipshidze, N. Gabelaia
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Today
modern, high technological methods of myocardium diagnostics are widely
used, and the methods for revealing the development of sever myocardium
pathologies in complete heart failure become more perfect. Besides,
definite relation to inflamatory disturbances is associated to protein
contractile ability decrease. This is observed in heart insufficiency.
Through the association between those two processes is not yet
studied. The
aim of the present work was to study the effect of some hydrolytic enzymes
on the contractility of several complex proteins of the contractile system
in intact myocardium and toxo-allergic myocarditis during myocardial
insufficiency. Neutral
protease – Calpain proteolitic activity was determined spectrometrically.
The effect of activated neutral protease, lysosomic acid phosphatase and
Cathepsin D on the contractility of skinired bundles and rigorous
connections and on the activity of isolated myofibril Ca-, Mg-ATPhase was
studied. Twelve non-pure-bred dogs (age – 1.5-2 yrs., weight 9-14 kg) and 103 rabbits (weight 1.780-2000g) were used for the study. All experimental animals were divided into two groups: control group (9 dogs and 36 rabbits, intact) and pathology simulation group (90 rabbits). In the latter group toxo-allergic myocarditis was simulated using S. Andreev’s method (1973). The rabbits were opened on day 10-post toxin administration. The
data achieved indicate that proteolitic activity of Calpain obtained from
the control rabbits’ hearts was two times higher than that from the
hearts of control dogs. Besides, it was observed that Calpain dependence
on proteolysis concentration in the concentration range of 5.10-5-5.10-2
M Ca was biophasal. In a normal healthy heart the activity increased to a
Ca concentration of 5.10-5-5.10-4
M Maximal activity was observed at the concentartion level of
5.10-5 M, and minimal – at 5.10-3 M. When
the materials were obtained from the rabbit myocardium with toxo-allergic
myocarditis, maximal activity was observed at 5.10-5 M calcium
concentration, and then it gradually decreased and achieved its minimal
value at 5.10-4 M. From this point down, the activity increased
again and remained stable at the concentration of 5.10-2 M. After 2-hour pre-incubation with Calpain in the Ca-free media, contractility of skinired bundles of the myocardium did not change; while with the increase of Ca concentration from 5.10-5 M to 5.10-3 M, Calpain obtained from the hearts of the normal enzyme. After 24-hr incubation with Ca at concentrations of 5.10-5 M to 5.10-3 M, the bundles completely lost this ability. It was found that under the 2-hour effect of Calpain obtained from the healthy heart rigorous tension decreased to normal; the action of pathologic enzyme was more pronounced and more rapidly destroyed rigorous connections. While the effect of Calpain on isolated myofibril Ca-, Mg-ATPhase activity was less pronounced.
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