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The activity of the enzymes: SDH,GIDH,LDH, GI-6-PDH, ATP-ase,PGM, G 6P-ase, PI, 6P-ase in myocardial tissue were studied under conditions of a 30-day experiment on albino rats, treated two hours daily, 5 days in the week, with noise with an intensity of 85 dB/A/ and 95 dB/A/. Under the effect of noise with intensity of 85 dB/A/ a tendency to inhibition of SDH and GIDH activity is observed, which after the treatment with 95 dB/A/ noise is statistically significant. With the latter noise level a significant enhancement of PI,6 P-ase activity is established as well as a tendency to enhancement of G6P-ase and ATP-ase activity. The data from the investigations carried out reveal the possibility of developing disturbances in the metabolism of myocardial tissue under noise effect.

The authors studied the changes in myocardium during a long-term effect of low carbon sulphide concentrations--50 and 10 mg/m3 by enzyme-histochemical, biochemical and classical histological and electron microscopic methods. THe data from the experiment provided evidence of the involvement of myocardium and vessels in destructive-adaptation reactions in case of carbon-sulphide effect, the destructive processes being with preponderance. They are conditioned both by metabolic disorders of energy-forming systems and the disturbed processes of transport and utilization of energy. Furthermore, the action coordination is disturbed as in the separate muscle cells and the totality of the tissue elements, forming the myocardium as well.

The effect of simultaneous exposure to noise and dimethylformamide (DMF), noise and xylol and also vibration and lead on the metabolism of the myocardium of albino rats was studied. Combined effect of the factors was examined by the method of bifactorial design of the experiment. The animals were exposed to noise, intensity 46, 85 and 95 dB (2 and 4 hours), DMF in doses of 0.25, 1.00 and 5.00 ml . kg-1 (5 days in a week), and xylol in a concentration of 300 mg . m-3 (4 hours, 5 days in a week) for a period of 1.5 months, as also to vibration, intensity 100 Hz, 4 m . sec-2 (2 hours) and lead acetate in a dose of 20 mg . kg-1 (daily for a period of 10 days). The activity of GlDG, SucDG, LDG, G6PDG, G6P-ase, PGM and CytO in the myocardium of experimental and control animals was examined. Disturbances in metabolic and energy processes in the heart muscle were established after both isolated and combined exposure to the effect of the factors. Results of bifactorial variance analysis demonstrate that combined effect of noise and DMF results in not only independent effect of the two factors, but also in their interaction. Isolated effect of two factors (vibration and lead) can be assessed according to the relationship of some enzymes; their interaction can be noticed in GlDG, ATP-ase and G6P-ase.(ABSTRACT TRUNCATED AT 250 WORDS)

The morphological picture of the myocardium of white rats after administration of cholesterol, cholic acid, and vitamin D2 was studied. After four weeks of atherogenic diet the hearts of rats showed severe lesions of intramural vessels in addition to disseminated necroses, granulomatous cell reaction of the stroma which was sometimes of the giant cell nature, and connective tissue proliferation. Non-uniform hypertrophy of the endothelium, edema and defibrilation of the media, proliferation of young connective tissue cells, outgrowth of reticular and collagen fibers, and deposition of calcium salts in the entire thickness of the vessel wall were observed, as well as destruction of the inner elastic membrane and its substitution with newly formed fibers and membranes. These changes may be associated with the toxic effect and sensitizing properties of vitamin D2 which was a component of the atherogenic diet used.

Biochemical, histological and electron-microscopic examinations of the heart and the aorta of albino rats exposed to carbon disulphide in concentrations of 10, 50, 100 and 200 mg . m-3 were carried out. Changes in the metabolic and energetic processes in the myocardium and in the quantitative and qualitative characteristics of the connective tissue of the aortal vessel wall were observed. The established disorders follow the dose-effect dependence. The authors studied the effect of carbon disulphide in concentrations of 10 and 50 mg . m-3 on the electrophoretic spectrum of serum proteins, the quantitative and qualitative characteristics of fibrous structures in the myocardium and the aorta of albino rats fed on atherogenic diet (cholesterol, cholic acid and vitamin D2). The combination of carbon disulphide with the atherogenic factor leads to intensification of changes in the cardiovascular system and in serum proteins, observed after independent exposure to either of the factors. The combination of atherogenic diet and 10 mg . m-3 carbon disulphide induced symptoms of intoxication, decreased survival of the animals, and the developing sclerotic process was found to be more severe and to progress more rapidly than in animals subject to atherogenic diet alone. The obtained results testify to cardiovascular effect of carbon disulphide. The observed atherogenic effect of carbon disulphide in low concentrations is most probably connected with its direct effect on the myocardium and the vessels.

The authors investigate the 12 month effect of the organophosphorus pesticide "Pyrazophos", in the myocardium status of albino male rats treated per os by 1/20, 1/100, and 1/200 LD50 of the preparation /LD50 for male rats 218 mg/kg/. The enzyme activity of ATP-ase, G6P-ase, F1,6 P-ase, PGlM, LDH, SucDH, iCDH, the quantity of soluble and insoluble collagen and elastin proteins were examined as well as the content of polycarbohydrate components /total and sulphated glycosaminoglycan and glycoproteins/ of the basic intercellular substance. The results point out that the preparation in doses 1.1 and 2.2 mg/kg and especially 11 mg/kg at continuous introduction cause cardiotoxic effect, and the changes affect first of all the components of the basic intercellular substance /with sGAG, GAG/ and to a lighter extent the enzyme activity in the cardiac muscle. The collagen and elastin proteins, constructing the fibrous structures remain comparatively stable. The experimental data have to be taken into consideration in the hygiene standardization of the organophosphorus preparation "Pyrazophos".

Effect of atherogenous diet (cholesterol, cholic acid and vitamin D2) on the state of collagen and elastin fibrilles as well as on content of proteins in rat blood serum, myocardium and aorta was studied by means of biochemical and histochemical methods. In sclerotic impairments the following phenomena occurred: a decrease in content of blood serum albumin, soluble tissue collagen and elastin and of insoluble elastin; an increase in content of globulins and haptoglobins in blood serum as well as of insoluble collagen in aorta and myocardium. The increase in content of insoluble collagen was accompanied by stimulation of growth of rough reticular and collagen fibrilles, deposition of calcium, fragmentation of the inner elastic membrane, by medionecrosis with deterioration of elastic tissue in aorta wall, in coronary arteria and in their intramural branches. These alterations in characteristics, properties and content of blood serum and tissue fibrillar proteins reflect only a part of complex processes involved in destruction of connective tissue under conditions of sclerosis.