[Activity of cAMP System in Sheep Lymphocytes and Platelets Exposed to External γ-Radiation in vivo].

The activity of the cyclic adenosine-3,5-monophosphate (cAMP) in lymphocytes and platelets of sheep has been studied for 15 days after animal exposure to total external γ-radiation at a dose of 4 Gy (LD50/30). The basal and E1 stimulated activity of adenylate cyclase and phosphodiesterase activity were determined by the thinlayer chromatography technique, and the cAMP content was determined using RIA-kits with 125J. Modification was revealed in the cAMP system functioning in the cell populations studied from the first day following radiation exposure. In particular, the basal adenylate cyclase activity in lymphocytes increased 1.7-4.3 times at all study dates, and stimulated enzyme activity increased on days 1-7, 21-8.8-fold compared to the initial data. Platelets showed increase in the basal adenylate cyclase activity on days I and 7, 2.7 and 35 times, and stimulated activity at the same times--9 and 5.7 times, respectively. The adenylate cyclase stimulation coefficient in lymphocytes raised 1.8 and 2.3 times on days 1 and 5, respectively, on day 7 it corresponded to the initial data and on days 10-15 it dropped below the control. However in platelets, this parameter did not have significant differences from the initial data. The phosphodiesterase activity in lymphocytes increased 3-fold on day 3, 2.4-fold on day 7, and in platelets it practically remained at the control level. The cAMP content in lymphocytes dropped within the first 12 hours and on day 3, 2.71 and 2.38 times, respectively, whereas in platelets it decreased 3.08 times within 12 hours and increased 1.91 times on day.3. At other times the cAMP content in lymphocytes and platelets did not differ from the initial data. The results suggest that the identified modification of cAMP system activity in lymphocytes and platelets in various periods after exposure of animals is based on different mechanisms. In the early period, alteration in the enzyme activity of cAMP system and cAMP content is caused by radiation effects on cytoplasmic membrane of cells circulating in the peripheral blood of animals. In the later periods, the recorded variations in the cAMP system activity are defined by the prevalence in the blood of more resistant to radiation damage cell subpopulation with an enhanced activity of cAMP enzymes and cAMP concentration corresponding to unexposed animals.

Evolution of Mechanical Stress (In-vitro) on Properties of Granulocytes in Acute Lymphoblastic Leukemia.

Acute lymphoid leukemia (ALL) affects the lymph cells or lymphocytes that make up the lymph tissue and prevents the proper maturation of the bone marrow cells. The processes through which cells convert mechanical stimuli into biochemical signals are called mechanical transitions and result in the sensation of specific cellular responses. In the present study, the functional properties of granulocytes of the patients with ALL were investigated using the in vitro mechanical stress model. The experimental part of the work was executed using blood from patients with ALL (n=30) being treated in the Hematological Department of Belgorod Region Hospital, Belgorod, Russia. The patients were in the age range of 18-45 years. Sample blood was obtained from all the patients who underwent a standard course of chemotherapy. Blood sampling was performed using a venepuncture and collected into the vacuum tubes Vacuette K3E. Blood samples from each experimental group were divided into two groups of control and experiment. The injection model of mechanical stress was used for the experiment group in vitro. Subsequently, the adenosine triphosphate (ATP) concentration increased by 1.8 times in this group, compared with the controls. Young's module, which numerically characterizes the rigidity of the granulocytes' plasmalemma, decreased by 54.4% (P<0.05) under the influence of mechanical stress. The surface potential of plasmalemma was not significantly different between samples in the group of control and experiment in patients with ALL. However, the adhesive force between erythrocyte and granulocyte increased by 30.7% (P<0.05). The osmotic load test showed an increase in the cell's volume during incubation. The use of membrane reserve by granulocytes increased by 47% (P<0.05) at the initial seconds of incubation. The obtained results pointed to the regulatory role of ATP molecules in intercellular signaling and add to the present literature regarding the mechanisms of intercellular interaction in the microvasculature on the development of leukemia. Moreover, the obtained results can be taken into account for the development of new pharmacological immune correctors.

[Assessment of lipid peroxidation and plasma membrane permeability for Ca2+ in the red blood cells of cattle after the long term grazing on radioactively contaminated territory]. / Otsenka perikisnogo okisleniia lipidov i pronitsaemosti plazmaticheskoi membrany dlia Ca2+ v éritrotsitakh krovi krupnogo rogatogo skota pri dlitel'nom nakhozhdenii na radioaktivno zagriaznennykh territoriiak

Ten years after the Chernobyl accident a physiological condition of cows was examined on radioactivy contaminated territory of the Novozibkov district of the Bryansk region. The long grazing of cattle on radioactivly contaminated territory revealed the increase in permeability of plasmatic membrane of the red blood cells to Ca2+ and the activation of process of lipid peroxidation. The sensitivity of the red blood cells of cows to incubations in hypertonic conditions was demonstrated.

[Increased plasma membrane permeability for Ca2+ in radiation-induced thymocyte apoptosis]. / Uvelichenie pronitsaemosti plazmaticheskoi membrany dlia Ca2+ pri radiatsionno-indutsirovannom apoptoze timotsitov.

Parameters of the Ca2+ permeability (the 45Ca influx rate in the presence of orthovanadate blocking the Ca(2+)-ATPhase, and the initial rate of the 45Ca uptake) and the DNA fragmentation were determined in rat thymocytes after gamma-irradiation-induced (with a dose of 5 Gy) apoptosis. Within the first 30-90 min after irradiation, the 45Ca influx rate that is characteristic of the membrane passive permeability remained unchanged. The initial rate of the 45Ca uptake that is characteristic of the Ca2+ exchange almost doubled. In 90-180 min, the rate of the 45Ca influx in the irradiated cells increased 1.5 to 2.0 times. An increase in the DNA fragmentation was observed in 90-120 min after irradiation of thymocytes; in 3 h, it developed up to 50%. Thus, modification of the membrane Ca2+ permeability in the irradiated thymocytes precedes a stage of initiation of the DNA degradation. A degree of disturbance of the membrane passive permeability increases as the thymocyte apoptosis progresses. The obtained data suggest that disturbance of the passive Ca2+ permeability and the intracellular Ca2+ homeostasis are responsible for the apoptosis of lethally irradiated thymocytes.

[Modification of Ca2+ metabolism in the blood cells of cattle with radiation-induced thyroid disorder after the Chernobyl nuclear power plant accident]. / Modifikatsiia obmena Ca2+ v kletkakh krovi korov s radiatsionnym povrezhdeniem shchitovidnoi zhelezy posle avarii na Chernobylskoi AES.

Increasing of Ca2+ concentration in cytoplasm and of the rate of 45Ca iflux into cows erythrocytes in 19-24 month after Chernobyl accident was revealed. Correlation between Ca2+ concentration in cytoplasm of erythrocytes and thyroxin content in plasma of cows with radioiodine damage of thyroid gland was found. Reduction of the rate of 45Ga influx into erythrocytes in cows with radiation doses of 20-60 By on thyroid gland was shown in later time after accident (3-5 years). Changes in Ca2+ permeability through membranes of erythrocytes and neutrophils after injection of 131I into calves in doses of 300 Gy and more on thyroid gland was found.

[Evaluation of cell membrane permeability for Ca2+ and adenylate cyclase in sheep peripheral blood cells, exposed to low doses of radiation]. / Otsenka pronitsaemosti plazmaticheskoi membrany dlia Ca2+ i aktivnosti adenilattsiklazy v kletkakh perifericheskoi krovi ovets, obluchennykh v malykh dozakh.

Chronic irradiation of sheep with doses of 2.6 and 12.9 mC.kg was characterized by the modification of the adenylatecyclase activity and Ca2+ permeability of plasma membrane in cells of the peripheric blood, with no changes in the clinical and hematological indicators. The observed effects are assumed to result from structural and dynamic variations in the lipids of membranes.

[Evaluation of hormonal status indicators and adenylate cyclase activity in animals in the follow-up of the Chernobyl AES accident]. / Otsenka pokazatelei gormonal'nogo statusa i aktivnosti adenilattsiklazy u zhivotnykh v otdalennye sroki posle avarii na Chernobyl'skoi AES.

Enhancing stimulation effect of prostaglandin E1 on adenylate cyclase, decrease in basal activity of adenylate cyclase in platelets and reducing thyroxine concentration in cow plasma 5 years after radioiodine damage to thyroid gland with doses higher than 200 Gy were detected, whereas only decrease in adenylate cyclase activity in platelets from animals irradiated with 40 Gy to thyroid gland was observed. No changes in platelet adenylate cyclase in cows exposed to less than 1 Gy to thyroid gland after 5 years of maintenance on the territory with 137Cs contamination density lower than 0.37 MBq/m2 were found.

[Changes in the spontaneous DNA-synthesizing activity in the peripheral blood lymphocytes of irradiated animals]. / Izmenenie spontannoi DNK-sinteziruiushchei aktivnosti v limfotsitakh perifericheskoi krovi obluchennykh zhivotnykh.

In lymphocytes of sheep exposed to 52 and 103 mC/kg radiation revealed was an increase in spontaneous incorporation of 3H-thymidine into DNA. A change in spontaneous DNA-synthesizing activity in lymphocytes of exposed animals was accompanied by the increase in the total protein content of the peripheral blood lymphocytes.

[The content of immunoreactive calmodulin in the blood cells of irradiated animals]. / Soderzhanie immunoreaktivnogo kal'modulina v kletkakh krovi obluchennykh zhivotnykh.

The immunoreactive calmodulin content was shown to increase in the irradiated platelets of rats and cows. Total Ca content did not vary significantly in platelets of exposed animals although there was a tendency toward its increase. At the same time, total Ca content in lymphocytes of irradiated cows increased while the immunoreactive calmodulin level remained unchanged.

[The effect of increased levels of chronic UVB-radiation on the functional state of the body in sheep]. / Vliianie povyshennykh urovnei UF-izlucheniia zony B na funktsional'noe sostoianie organizma ovets pri ego khronicheskom deistvii.

The effect of increased doses of UV-B-radiation produced by LER-40 lamps (with an intensity of 5.5 W/m2 at a daily dose of 20 kJ/m2 and a total dose for 15 days of 300 kJ/m2) on the cardiovascular function, biochemical, biophysical and structural parameters of blood plasma and cells of sheep was investigated. It was found that increased UV-B-radiation produced functional changes in different physiological systems of animals: arrhythmias, diastole shortening, increase of the systole-diastole index; decrease of platelet count, shortening of blood coagulation time; increase of calcium, iron and copper and decrease of zinc in plasma; conformational changes in cytoplasmic membranes of platelets and lymphocytes. The changes that occurred in the sheep at an early stage of exposure can be viewed as adaptive. However, functional changes that were seen at remote stages suggested that the sensitivity of various systems of the body to UV-B-radiation was different.