THE ROLE OF RADIOACTIVE METHODS IN THE DIAGNOSTIC TYPE OF HYDRONEPHROSIS IN CLEAN-UP WORKERS OF CHORNOBYL ACCIDENT

RATIONALE

Since the introduction of radionuclide research methods into clinical practice, they occupy an importantplace in the diagnosis of hydronephrosis and, at the same time, sufficiently objective, sensitive and atraumaticmethods of investigation.

OBJECTIVE

On the basis of retrospective data, to investigate the diagnostic role of radionuclide renography (RRG)and the method of indirect radionuclide renangiography (IRAG) in clean-up workers of Chornobyl accident withhydronephrosis.

MATERIALS AND METHODS

A total of 257 patients with hydronephrosis (140 women and 117 men) aged 15 to 77 yearswere examined by the RRG and the IRAG. The RRG technique consists of intravenous administration of a solution of131I-hypurane (2.5 kBq/kg) and continuous registration for 20 minutes of the level of radioactivity above the kid-neys with the help of sensors of the renograph UR 1-1. The IRAG was conducted for 30-45 seconds with exposure1 frame per second after intravenous administration of a solution of 99mTc-pentatech (2 MBq/kg).

RESULTS

The results of the radionuclide study of the hemodynamics of patients with different stages ofhydronephrosis made it possible to draw a conclusion regarding the expediency of taking into account the condi-tion of the cup-pelvic system in the preoperative period, as well as the parameters of the arterial and venous circu-lation.

CONCLUSIONS

Combined use of X-ray and radionuclide methods allows establishing the cause and consequences ofhydronephrosis, to develop a rational treatment plan. RRG and IRAG are reliable methods of dynamic control in post-operative observation of clean-up workers of Chornobyl accident with hydronephrosis.

Peculiarities of ultrastructural organization and metabolism of reactive forms of oxygen and nitrogen in a cardiovascular system for permanent effects of ionizing radiation in low doses

OBJECTIVE

Determination of the peculiarities of ultrastructural changes and metabolism of reactive forms of oxy gen and nitrogen in the tissues of the myocardium, aorta and portal vein of the radiosensitive BALB/c mice due long term exposure to the complex of radionuclides of Chоrnobyl fallout (ejection) and low intensity low dose γ irradiation.

MATERIALS AND METHODS

Experimental studies were performed on 60 mice female radiosensitive lines BALB/c with a body weight of 20-22 g, which were divided into 3 groups: I group (control) animals age 6-9 months which were born and lived their lives in Kyiv vivarium under conditions natural radioactive background; ІІ - animals age 6 months, which were born and lived in the Chornobyl exclusion zone throughout their lives; ІІІ - animals, which from 3 months of age for 6 months were constantly located in cages with flat ionizing radiation sources and exposed to external γ irradiation in a total dose of 0.43 Sv. Animals of II and III groups were kept in the vivarium of the Institute for Safety Problems of Nuclear Power Plants of the National Academy of Sciences of Ukraine (Chornobyl). Mice of the BALB/c lines are sensitive to radiation: for males LD 50/30 < 5.7 Gy, for females - 5.85 Gy.

RESULTS AND CONCLUSIONS

The peculiarities of structural and functional changes in the organs of the cardiovascular system (CVS) and mechanisms of the development of oxidative and nitrosatitative stress due long term exposure to the complex of radionuclides of the Chornobyl fallout (ejection) and low intensity low dose γ radiation based on the study of ultrastructural organization and metabolism of reactive oxygen species (ROS) and nitrogen (NRS) of the atri al cardiomyocytes (CMC), the aortic endothelium and portal vein of the BALB/c mice. Found that the permanent expo sure to low doses of radiation changes occur, including the dominant mechanism is to run a CMC apoptosis and endothelial cells of the aorta and portal vein. It is shown that the development of oxidative stress accompanied by increased activity of ROS metabolism that occurs due to activation of nucleotide and lipid superoxide generators. Found that under these conditions the development of nitrosative stress is due to the activation of inducible NO syn thesis enzyme iNOS and inhibit its synthesis constitutive eNOS enzyme. High levels of simultaneous generation of superoxide and NO, bindting, lead to the formation of toxic peroxynitrite, which initiates the process of apoptosis.

The role of three phase bone scintigraphy in arthroplasty of hip and knee joints of clean-up workers of Chornobyl accident

OBJECTIVE

The objective of the work to determine the diagnostic role of the three phase bone scintigraphy (3 F BS) in the early prediction of paraendoprosthetic complications of the hip and knee joints of the participants in clean up workers of Chornobyl accident.

MATERIAL AND METHODS

The 3 F BS method were investigated the radionuclide kinetic parameters of the inclusion and distribution of radiopharmaceuticals (RF) in damaged joints in the 75 male clean up workers.

RESULTS

It was established that calculating the quantitative indices of kinetics of the drug at various stages of the 3 F BS allowed to determine statistically significant differences in metabolic changes in focal lesions in articular structures. Thus, the differential diagnostic capabilities of the radionuclide method of examination of patients with arthroplasty of the hip and knee joints are elevated.

CONCLUSIONS

The kinetics of osteotropic RF in the foci of fixing the damaged hip and knee joints in the infectious and inflammatory processes is characterized by the predominance of retention and specific accumulation of the drug in the early static phase and the delayed static phase of the 3 F BS compared with the centers of fixation of RF in deforming osteoarthroses, which correlates with the differences in destructive reparative processes in them.

[Carcinogenic aspects of indeterministic effects of ionizing radiation]

The results of clinical and epidemiological investigations on cancer diseases with different localization in irradiated persons are reviewed in the paper. The data on mechanisms of morbidity of mamma, thyroid, broncho-pulmonary, blood cancer in exposed to different doses of ionizing radiation persons are analyzed.

[Genetic aspects of indeterministic effects of ionizing radiation]

The theoretical and practical data on damage of cell genome using modern investigating methods in persons exposed to ionizing radiation are revealed. The mechanisms of cell genome damage as a basis of cancerogenesis in exposed to different doses of ionizing radiation persons are analyzed.

[Changes of vascular reactivity and reactive oxygen species in conditions of varying duration of permanent stay in the alienation zone in mice]

Peculiarities of changes in the vascular reactivity and in the content of reactive forms of oxygen and stable metabolites of nitric oxide (NO) were studied in the aorta preparations of C57BL/6 and BALB/c mice of the two age groups (6 and 18 mo.), which were born and permanently kept in the Chernobyl alienation zone. The results obtained showed a disturbance of acetylcholine-induced endothelium-dependent reactions of relaxation of smooth muscles of the thoracic aorta. A lower level of NO synthesis and lower level of oxidative arginase metabolism of arginine corresponded to a higher degree of damage of endothelium-dependent reactions of relaxation of the thoracic aorta smooth muscles. A decrease of NO synthesis in conditions of permanent effects of low doses of radiation was conditioned by an increase of generation of reactive forms of oxygen, namely, superoxide and hydroxyl radicals, which might be formed in mitochondria. In conditions of permanent effects of low doses of radiation a lesser level of protein nitrosothilation, same as lesser one of generation of OH-radical, corresponded to a higher level of damage of endothelium-dependent reactions.

[Influence of enalapryl on vasomotor reactions of rats with chronic deficiency of dopamine in the mesencephalo-striatal system]

The results of experiments on isolated preparations of aorta and portal vein of rats with chronic deficiency of mesencephalo-striatal dopamine have shown that endothelium-dependent reactions of dilatation were inhibited. If rats with dopamine deficiency received enalapryl (20 mg/kg) these reactions partly recovered. A possible conclusion may be that in conditions of cerebral dopamine deficiency the functional state of endothelium got worse, and endothelium-dependent dilatation of vascular smooth muscles was inhibited. The use of inhibitor of angiotensin-converting enzyme enalapryl resulted in a significant restoration of the above vascular reactions.

[Effect of enalapril on endotheliun-dependent contractile reactions and oxygen cost of work of the smooth muscles in experimental diabetes mellitus]

The influence of angiotensin-converting enzyme on endotheliun-dependent contractile vascular reactions was investigated on the rat model of streptozotocin-induced diabetes mellitus. It is shown, that the long-term administration of enalapril results in partial restoration of disturbed at diabetes mellitus reactions and also to reduction of oxygen cost of smooth muscles and myocardial work. Thus, after 28-day's of oral administration of this drug the restoration of endotheliun-dependent dilatation of aorta and coronary vessels, increase of stretch-induced contractile responses of vascular smooth muscles, reduction of stiffness of isolated portal vein strips are observed. Possible mechanisms of such changes are following: increase of nitric oxide synthesis (at the expense of constitutive NOS activity) and reduction of oxidative stress, to what the decrease of diene conjugates contents in tissues of animals with diabetes mellitus after long introduction of enalapril testifies.

[Mechanisms of contractile reaction changes and efficiency of oxygen utilization by portal vein smooth muscles in experimental diabetes mellitus]

On the rat portal vein isolated strips the essential reduction of contractive response, increase of stiffness of vascular smooth muscles at their stretching and increase of oxygen value of smooth muscles' work are revealed in conditions of experimental diabetes mellitus. The possible mechanism of such infringements is chronic hyperglycemia, which results in development of oxidative stress and reduction of NO synthesis by constitutive NOS. Indeed, the significant decrease of activity of constitutive NO-synthase and increase of the oxidative stress markers contents are shown at experimental diabetes mellitus. The similar infringements are marked at in vitro model of hyperglycemia, blockade of NO-synthase and in conditions of oxidative stress. Additional confirmation of a role of NO synthesis blockade and oxidative stress in development of such infringements at diabetes is fact that application of antioxidant melatonin and L-arginine, a precursor of NO to diabetic animals results in partial restoration of contractive reactions, reduction of stiffness and oxygen value of smooth muscles' work.

[In the foreground of fundamental investigations. The 50th anniversary of "Fiziologichnyi Zhurnal"]

50 years have passed from time of publication of the first number of "Fiziologichnyi Zhurnal", that is the scientific-theoretical edition of a National Academy of Sciences of Ukraine and O.O. Bogomolets Institute of Physiology. "Fiziologichnyi Zhurnal" is a leading Ukrainian academical periodical edition, informing scientific community about a condition of physiology and pathophysiology, state-of-the-practice in physiology. In different years the journal was headed by the outstanding scientists--physiologists academicians G.V. Folbort, A.F. Makarchenko, F.N. Serkov. Now the editor-in-chief of "Fiziologichnyi Zhurnal" is corresponding member NAS of Ukraine V.F. Sagach.

[Age-related characteristics of contractile vascular reactions and the content of oxygen free radicals and nitric oxide metabolites in BALB/c mice in conditions of alienation zone]

Peculiarities of changes of the endothelium-dependent and endothelium-independent vascular reactions of relaxation, and the content of oxygen free radicals and stable metabolites of nitric oxide (NO) were studied in the aorta preparations of BALB/c mice of the two age groups (6 and 18 months), which were born and lived in the Chernobyl alienation zone. The results obtained showed no endothelium-dependent reactions of aortal smooth muscles relaxation to acetylcholine and only partially impaired endothelium-independent reactions to sodium nitroprusside in animals of both age groups. There was a significant decrease in the content of high-molecular nitrosothiols (HMNT) in old animals, which may signify a depletion of NO depot in the aorta. A decrease of HMNT levels induced an increase of the shares of anion nitrite and low-molecular nitrosothiols (LMNT) in the total amount of endogenous donors of NO in the aorta of old animals. Exposure of old animals to low doses of radiation resulted in an over 3-fold increase of LMNT. In old mice the levels of oxygen active forms, superoxide and hydroxyl radicals increase, while the level of H2O2 remained unchanged.

[70th anniversary of the O.O. Bogomolets Institute of Physiology of the National Academy of Science of Ukraine]

The brief history of creation and basic stages of development of the largest centre of science of the country and global physiological science--A.A. Bogomolets Institute of physiology of National Academy of Sciences of Ukraine is stated. The basic achievements of scientific divisions of Institute for the 70-year's period in area of the most urgent problems of molecular physiology, neurophysiology, physiology of visceral systems are marked. Is covered many-sided and versatile scientific and publishing activity of the employees of Institute, the role of the outstanding scientists--physiologists and biophysicists of Institute in formation of national scientific schools is shown.

[Mechanisms of nitric oxide activity in cardiovascular system as a basis of pathogenetic therapy of related diseases]

General characteristics and mechanisms of effects of nitric oxide (NO) and its role in the development of pathology are reviewed. Presented are the data about NO participation in the regulation of circulation and cardiovascular system; NO-dependent mechanism of regulation of cardiovascular reactivity against the background of dysfunction of endothelium; cGMP-independent mechanism of NO effect upon Ca homeostasis and the sensitivity of myofibrils of smooth muscle cells to Ca ions; pharmacological correction of disturbances of NO metabolism and related endothelial dysfunction; role of age changes of the endothelial function in the development of cardiovascular pathology.

[Changes in vasodilator responses of vascular smooth muscles and nitric oxide system in experimental diabetes mellitus]

The experimental data of endothelium-dependent and endothelium-independent responses of vascular smooth muscles of isolated preparations of the thoracic aorta of rats with experimental diabetes mellitus (streptozotocin-induced diabetes) and a control group of animals are presented in the article. It has been shown that at diabetes mellitus endothelium-dependent vasodilation was deteriorated to the most extent. It resulted from dysfunction of the endothelium due to a reduce in the synthesis of NO. This conclusion was based on the data of the parameters of the contents of steady metabolites of nitric oxide (NO2- and NO3-), as well as activities of inducible and constitutive NO-synthases (iNOS and cNOS) in heart, aorta, erythrocytes and blood plasma in diabetic and control animals.

[Effect of acetylcholine and adenosine triphosphate on membrane potential of intact rat aorta endothelium in aging]

Changes in the electric reactions of intact endothelium of isolated rat aorta were studied in conditions of aging. A value of resting membrane potential of endothelium of old rats (24-26 mo) was significantly greater, than in control group of animals (6 mo). In responses to acetylcholine and ATP the old rats did not show a typical course of reactions, which was peculiar to control animals. Inability of old rats to produce a typical response to acetylcholine and ATP may signify a disturbance of links between endothelial cells, which resulted in functional clusterization of the latter. The data obtained suggest a possible mechanism of decrease in production and release of potent vasodilator--nitric oxide--due to changes that occur in the electric properties of endothelium in aging.

[Endothelium-dependent contractile reactions of vascular smooth muscles and content of oxygen free radicals in aging rats]

Endothelium-dependent and endothelium-independent reactions of vascular smooth muscles were studied in isolated preparations of thoracic part of aorta and portal vein of rats of two age groups--6.8 mo. (control) and 24-26 mo. (old animals). In old rats the disturbances occurred primarily in endothelium-dependent vascular reactions. This age-related dysfunction of endothelium resulted in inhibition of NO-dependent regulation of vascular tone. Age-related changes in the state of plasmic membranes of erythrocytes were established using a method of acid hemolysis. Age-related changes in the levels of active forms of oxygen (.O2-, H2O2, .OH-) and nitrogen (NO2-, NO3-) were determined in the myocardium, aorta, blood plasma and erythrocytes of adult and old animals.

[The length-force dependence of vascular smooth muscles and the nitric oxide system in a chronic deficiency of mesostriatal dopamine]

This study investigated the influence of the chronic cerebral dopamine deficiency after 6-hydroxydopamine lesions of dopaminergic mesostriatal system and NO pathways on the length-tension relation in vascular smooth muscles to their distension. Experiments were performed on isolated strips of rat portal vein. The results indicate that the attenuated contraction responses and the increased stiffness of vascular smooth muscles to the distension in a chronic mesostriatal dopamine deficiency. It was found that these responses may be, in part, normalized after a long-term L-arginine administration. The same changes were marked in the responses of intact vascular strips after the inhibition of NO-synthase activity and L-arginine perfusion. It has been suggested that, in a chronic mesostriatal dopamine deficiency, the reduced vascular reactivity was due to the decreasing of NO synthesis by endothelium and L-arginine could be used in the treatment of these vascular disorders.

[The structural organization of the aortic endothelium in hypercholesterolemia and the effect of L-arginine]

Electron microscopic investigation of the rabbit [correction of rat] thoracic aorta revealed endothelium to be most vulnerable to the damage in experimental hypercholesterolemia. Administration of precursor of nitric oxide L-arginine against the background of hypercholesterolemia resulted in activation of functional activity of the endothelium of aorta. This notion is supported by an increase of the quantity of protein-synthesizing structures (ribosomes, polysomes, canaliculi of endoplasmic network), secretory granules vs rabbits on atherogenic diet. At stimulation of NO-synthase activity of endothelium the dilatory reactions of aortal strips to acetylcholine are improved.

[The effect of L-arginine on the ultrastructure of atrial cardiomyocytes in experimental hypercholesterolemia]

The results of electronmicroscopic study of the right atrium in experimental hypercholesterolemia revealed a disturbance of ultrastructural organisation of both cardiomyocytes and endothelial cells of blood microvessels. Intake of L-arginine--a precursor of synthesis of nitric oxide (NO)--with atherogenic diet was found to prevent to some extent the damage of ultrastructural organisation of cardiomyocytes and to stimulate the production of atrial granules. A significant number of secretory components, which differ in terms of structure and function, revealed in the endothelium of blood microvessels may testify to the fact that upon administration of L-arginine the paracrine effect of hormonal regulation is enhanced manifesting itself through an increase of synthesis and secretion of natriuretic hormone in atrial cardiomyocytes. A tissue hormonal system is displayed through an increase of synthesis and secretion of atrial natriuretic hormone in cardiomyocytes. On the other hand, a NO precursor L-arginine may produce a correcting effect upon the ultrastructure of endotheliocytes in hypercholesterolemia.

[The role of endothelin in the contractile reactions of vascular smooth muscles in hypertensive rats]

Experiments on isolated strips of rat v. portae revealed that endothelin participates in the development of myogenic reactions of vascular smooth muscles. Endothelin is known to be released by endotheliocytes and to stimulate the contraction of vascular smooth muscle cells. Rats with inherited arterial hypertension showed significant decrease of the stimulating effect of endothelin-1 upon the contraction of vascular smooth muscles. At the same time, the effect of phosphoramidon, an inhibitor of endothelin-converting enzyme, upon the length-tension curve of the strips of v. portae is more marked in hypertensive vs. control rats. The data obtained testify to the fact that the increase of vascular tone in the hypertensive rats is most likely to be conditioned by the involvement of endothelin.

[The contractile reactions of vascular smooth muscles in hypercholesterolemia and changes in the functional activity of the endothelium]

Experiments on the isolated stripes of the portal vein of rabbits in experimental hypercholesterolemia and/or inhibition of endothelium's synthetic function with NO-synthase inhibitor L-NAME revealed the decrease of the contractile responses of vascular smooth muscles to stretching, as well as endothelium-dependent relaxation of aortal stripes to acetylcholine. L-arginine stimulated the synthetic activity of endothelium, thus enabling to use it for the correction of functional disturbances of the endothelium and of the studies responses.

[The role of the endothelium and of biologically active substances of endothelial origin in regulating blood circulation and cardiac activity]

The role of endothelium and its biologically active derivatives in the central and local control of circulation is under consideration. Molecular and cellular mechanisms of the activation of the endothelium-dependent responses of different functional significance are being discussed, as well as the state of endothelial responses in the development and compensation of pathological processes in the cardiovascular system.

[The role of the endothelium in the vascular effects of vintoperol]

The effects of vintoperol have been studied in the experiments on the vascular bed of femoral artery of 15 mongrel dogs under chlorazol-urethane narcosis and on isolated vascular preparations of rats. It is shown that ++de-endothelization of vascular bed using saponin and mechanical removal of endothelial stripes decreased the vasodilatation reaction and relaxation of stripes by 50-60% of the initial values. While infusing ventoperol (0.3 mg.kg-1 min-1) to ++de-endothelized vascular bed, the blood flow increased by 18 +/- 5% as against 47 +/- 3.9% of the initial value under intact endothelium. Blockade of guanylate cyclase by methylene blue decreased blood flow under vintoperol action to 24 +/- 3.5%. The similar results are obtained in the experiments in vitro. After ++de-endothelization of pulmonary artery++ the amplitude of relaxation of preactivated smooth muscles decreased vs. initial tone (21 +/- 3.7% vs. 56% +/- 5.3%). Inhibition of relaxation reaction of vascular stripe under vintoperol effect is also observed after treatment with gossypol, or methylene blue. Thus, endothelium is involved in the realization of vasodilating effect of vintoperol, its action being mediated by endothelium--derived relaxing factor.