Relationship of Inotropic Effects of Stimulation of ß1- and ß2-Adrenergic Receptors of Isolated Myocardial Fragments with Echocardiography Parameters in Coronary Heart Disease.

We studied the relationship of inotropic responses of the isolated myocardium to stimulation of ß1-and ß2-adrenergic receptors (ß-AR) with echocardiography parameters in 28 patients with coronary heart disease (CHD). Myocardial fragments (trabeculae of the right atrial appendage) were obtained during coronary artery bypass surgery. The inotropic response of the trabeculae was assessed in an isometric mode. Stimulation of ß1-and ß2-AR with agonists was performed against the background of preliminary α-AR blockade. In case of preserved ejection fraction, significant inotropic response of the trabeculae (135 (112; 154)% from the initial contraction amplitude) was observed after ß1-AR stimulation, while in reduced ejection fraction, its significant increase was observed after ß1-AR stimulation (126 (112; 170)% from the initial contraction amplitude). In patients with preserved and reduced ejection fraction, the correlations between the inotropic responses of the trabeculae to ß1-and ß2-AR stimulation and echocardiography parameters were different. The revealed differences reflect the degree of cardiac remodeling under condition of the studied pathology.

[Biomarkers of Inflammation in Predicting the Outcomes of Heart Failure of Ischemic Etiology: the Results of Factor Analysis].

AIM: To study the prognostic significance of inflammatory biomarkers in patients with chronic heart failure (CHF) and stenotic multivessel coronary atherosclerosis, with determination of the biomarker separate set that reflects subclinical inflammation and is associated with the development of cardiovascular complications during prospective observation. MATERIAL AND METHODS: A prospective observational study was conducted that included 80 patients with CHF and ischemic heart disease who were scheduled for coronary artery bypass grafting (CABG) during their current hospitalization. In addition to routine clinical laboratory tests, coagulation parameters were evaluated and the following inflammatory biomarkers were determined: neutrophil gelatinase-associated lipocalin (NGAL), growth/differentiation factor 15 (GDF-15), fibroblast growth factor 23 (FGF-23), transforming growth factor beta-1 (TGF-ß1), and high-sensitivity C-reactive protein. Also, the calculated neutrophil-to-lymphocyte ratio (N LR) was included in the analysis. Follow-up duration was at least 12 months (median 16 [13, 22] months). Statistical analysis of the data was performed with the IBM SPSS Statistics 21 software. RESULTS: The study presented results of a factor analysis of 10 inflammatory biomarkers in patients who were scheduled for CABG. One of the factors identified by the analysis included the levels of NGAL and GDF-15, N LR, and the level of fibrinogen in the blood in CHF patients with stenotic coronary atherosclerosis and was significantly associated with the death rate during prospective observation. Furthermore, this association remained significant even after adjustments for age, glomerular filtration rate, severity of heart and coronary insufficiency, and the presence of diabetes mellitus. CONCLUSION: In patients with CHF and stenotic coronary atherosclerosis, a set of inflammatory markers, including blood NGAL, GDF-15, N LR, and fibrinogen, can be combined into one factor reflecting subclinical inflammation. The value of this factor can be used to predict cardiovascular death in the long term after surgical myocardial revascularization.

Wound healing activity of aqueous dispersion of fullerene C60 produced by "green technology".

In addition to exhibited antioxidant and anti-inflammatory activity, fullerene C60 is a promising wound healing agent. An important stage in the production of fullerene-based ointments is the stability of the aqueous fullerene dispersion (AFD) with minimum size of colloidal fullerene aggregates and sufficiently high concentration. To achieve these parameters tangential flow filtration of fullerene C60 was used ("green technology"). As estimated by small-angle neutron scattering and dynamic light scattering purified AFDs with narrow-size distribution nanoclusters have a size of 6 nm and are assembled into agglomerates which reach a size of 150 nm. The ability of the AFD to exhibit regenerative activity was studied using the animal wound model. This study shows for the first time that the fullerene-based composition stimulates the healing of wounds of various origins. We assume that the mechanism of the AFD wound-healing activity is associated with the aryl hydrocarbon receptor and macrophages activity.

Humanized Mice as a Model to Assess the Response of Human Hematopoietic Stem Cells to Irradiation.

NOD SCID mice were humanized by transplanting human hematopoietic cells isolated from umbilical cord blood. A dose-dependent death of hematopoietic cells and their subsequent recovery were shown after acute external γ-irradiation in the model of humanized mice. The proposed approach can be used for preclinical studies of radioprotective agents and for assessment of the impact of adverse factors on the survival rate and functional properties of human hematopoietic stem cells in vivo.

[Functional state of a solitary kidney after nephrectomy for renal cancer].

INTRODUCTION: The outcome of surgical treatment of renal cancer depends not only on cancer-specific survival, but also on the degree of loss of renal function, which often develops after surgery, especially radical nephrectomy. AIM: To study the features of functional changes in a solitary kidney as a compensation mechanism after radical nephrectomy for renal cancer. MATERIALS AND METHODS: The functional state of a solitary kidney in 36 patients with renal cancer who undergone to radical nephrectomy was evaluated. There were 20 and 16 women. The mean age was 59.0+/-10.8 years (from 39 to 76 years). The size of the tumor was in the range of 7.0-12.0 cm. All patients with a solitary kidney underwent a follow-up examination 3 months after surgery, including measurement of peripheral blood pressure with calculation of mean dynamic pressure, renal ultrasound, calculation of glomerular filtration rate (GFR), renal doppler ultrasound, determination of serum fibrinogen and fibrin monomers, and microscopy of the bulbar conjunctiva. Patients who had pathological abnormalities during the examination were prescribed reno-cardioprotective drugs, including perindopril in a titrated dose, apixaban 5 mg a day as thromboprophylaxis and for improvement of the flow properties of blood for a period of 3 months with re-evaluation of the above parameters. RESULTS: In 61.1% of patients after radical nephrectomy, on 2-4 postoperative days, there was a tendency to increase blood pressure compared to baseline values (p<0.05). By the seventh day after the procedure, the volume of the contralateral kidney increased on average by 16% (from 110.4+/-11.2 cm3 to 132.4+/-4.8 cm3, p<0.05). After radical nephrectomy, a decrease in GFR was detected in 33 cases (91.7%; p<0.05). Renal doppler ultrasound showed a moderate increase in linear blood flow, the resistance index in the main renal artery, and a decrease in the pulse index in the segmental and arcuate arteries. The microscopy of the bulbar conjunctiva in 83.3% of patients revealed changes in the microcirculatory bed, including narrowing of arterioles, dilation of venules, a decrease in venular and capillary blood flow. After 3 months of reno-cardioprotective therapy, it was revealed that the target values of blood pressure (<130/85 mm Hg) were achieved with an average dynamic blood pressure of 93.4+/-2.6 mm Hg. In addition, a decrease in creatinine to an average of 106.2+/-6.4, fibrinogen and fibrin monomers to subnormal values of 3.2+/-0.2 g/l and up to 8.1+/-0.5x10-2 g/l, respectively were seen. Renal hypertrophy according to ultrasound examination was preserved with a mean kidney volume 119.7+/-3.6 cm3. Disturbances in peripheral microcirculation according to the microscopy of the bulbar conjunctiva was assessed as moderate. CONCLUSION: The development of CKD in patients with a solitary kidney is accompanied by a structural reorganization of the organ with an increase in blood pressure, an increase in its volume, a decrease in function, microcirculatory disorders and hypertensive nephropathy. Considering the prognostic significance of changes in the solitary kidney, it is important not only to control the functional parameters, but also to include reno- cardioprotective therapy as a standard, since it contributes to the preservation of the renal function and prevents the rapid progression of CKD. Thus, medical and social rehabilitation of patients with a solitary kidney is required. However, it is currently cannot be considered comprehensive.

[Assessment of the results of left ventricular reconstruction in combination of coronary atherosclerosis and diabetes mellitus]. / Otsenka rezul'tatov rekonstruktsii levogo zheludochka pri sochetanii koronarnogo ateroskleroza i sakharnogo diabeta.

AIM: To study the effect of type 2 diabetes mellitus on changes of intracardiac haemodynamics and myocardial morphology in patients with ischaemic heart disease and a postinfarction aneurysm of the left ventricle before and after corrective operations on the heart. PATIENTS AND METHODS: The study included 79 patients with ischaemic heart disease and a chronic aneurysm of the left ventricle (Group I - patients with type 2 diabetes mellitus (n=27), mean age 57.5±3.9 years, average number of shunts 2.9±0.6; Group II - patients without diabetes mellitus (n=52), mean age 55,3 ±7.1 years, average number of shunts - 2.7±0.3). In the preoperative period all patients were examined taking into account the functional class of angina pectoris, with the assessment of the left ventricular ejection fraction, end-diastolic index, end-systolic index, sphericity index. All patients underwent coronary artery bypass grafting and surgical restoration of the normal geometry of the left ventricle according to the Menicanty technique with the target end-systolic index of 60 ml/m2, during which 39 patients from both groups were subjected to intraoperative biopsy of the left ventricular myocardium and right atrial auricle. RESULTS: The intergroup analysis revealed no statistically significant differences in age, angina pectoris class, level of arterial pressure between the groups. Neither were there statistically significant differences in the echocardiographic parameters at the preoperative stage. In the postoperative period, we detected a significant decrease in the end-systolic and end-diastolic volumes of the left ventricle in both groups, with a statistically significant increase of the left ventricular ejection fraction observed only in non-diabetic patients. One year after the operation, such patients still continued to demonstrate more favourable parameters of the systolic and diastolic functions of the left ventricle. A detailed analysis with determining the delta of the alterations in the parameters revealed more significant positive dynamics in the postoperative period in patients with ischaemic heart disease not associated with type 2 diabetes mellitus. CONCLUSION: The obtained findings are indicative of negative dynamics of the course of chronic ischaemic heart disease aggravated by type 2 diabetes mellitus after reconstruction of the left ventricle. Macro- and microangiopathy in type 2 diabetes mellitus significantly deteriorated the myocardial trophism. Subsequent bleedings draw phagocytic cells into the myocardial stroma, thus adversely affecting the further prognosis and course of the disease, since we demonstrated that the presence of inflammatory infiltrate in the myocardial stroma is a key factor of unfavourable outcomes of surgical treatment of patients with ischaemic cardiomyopathy.

[Prospects For the Use of Peptides against Respiratory Syncytial Virus].

The human respiratory syncytial virus (RSV) is one of the most common viral pathogens that affects the lower respiratory tract and could be a reason of bronchiolitis and/or pneumonia. Currently, there are no available effective ways of treating the RSV infection. Attempts to develop preventive vaccine have been unsuccessful. The only therapeutic agent used for RSV treatment is virazole (ribavirin); however, it induces adverse effects. Medications based on neutralizing monoclonal antibodies, such as IGIV (Respigam), palivizumab (Synagis), and MEDI-524 (Numab), are under clinical trials; however, their use will be limited by their high cost. One of the promising approaches for antiviral therapy is the use of natural peptides (defensins and cathelicidins), or their synthetic analogs. The majority of currently described antiviral peptides are developed against the human immunodeficiency virus, the herpes simplex virus, and the influenza virus. At the same time, a body of experimental data evidencing anti-RSV activity of peptides has been accumulated. The main advantages of peptide drugs are their wide spectrum of antiviral activity and low toxicity. However, there are obstacles in implementing peptide-based drugs in clinical practice. Due to their low resistance to the action of serum proteases, most authors consider peptides promising only for local application. Given that RSV affects the epithelium of the respiratory tract, where the protease activity is lower than in the systemic circulation, it is possible to develop locally active peptide drugs, for example, as inhalation forms. Their stability could also be increased by the synthesis of dendrimer peptides and by the development of recombinant peptides as precursor proteins. Anti-RSV peptides can be divided into several groups: (1) attachment and/or fusion blockers; (2) peptides displaying direct virucidal activity, disrupting the viral envelope. Such peptides, which suppress early stages of the viral life cycle, are considered prophylactic agents. However, for several peptides, their immunoregulatory properties have been described, which opens the possibility for therapeutic use. This review summarizes the information on the antiviral properties of such peptides and mechanisms of their action and describes the prospects of the future development of antiviral peptides.

[Surgical Treatment of Ischemic Cardiomyopathy: Current State of the Problem].

In this article we present discussion of the current state of the problem of surgical treatment of ischemic cardiomyopathy (ICM). The pathophysiological aspects of left ventricular remodeling in patients with ICM are also covered. A detailed characterization of methods for assessing the myocardial viability is given and their role in patients with ICM is shown. The problem of right ventricular dysfunction in ICM is discussed. Main attention is focused on the methods of surgical treatment of ICM. Limitations of the Surgical Treatment for Ischemic Heart Failure (STICH) study are analyzed. The article is intended for cardiologists, general practitioners and cardiac surgeons.

[Functionality of mammary-coronary bypass grafts according to the data of intraoperative flowmetry]. / Funktsional'nost' mammarokoronarnykh shuntov po dannym intraoperatsionnoi floumetrii.

Improvement of surgical treatment for ischaemic heart disease is one of the main trends in modern medicine. After the operation of coronary bypass grafting, further functioning of blood flow in the grafts largely depends upon its domination over the native blood flow in the target coronary arteries. Therefore, intraoperative diagnosis of functional competence of coronary bypass grafts by means of flowmetry is currently of special importance. The purpose of this study was flowmetric quantitative assessment of the curves of blood flow through the coronary bypass grafts, depending on the degree of stenosis of the target coronary arteries. A total of 135 patients were examined during our study. We evaluated the curves of blood flow through the bypass grafts from the left internal thoracic artery to the anterior descending artery. The bypass grafts were divided into three groups: the 1st group (n=47) with moderate stenosis of the coronary arteries (from 50 to 75%); the 2nd group (n=42) with a more pronounced lesion of the target vessel (from 75 to 99%), and the 3rd group (n = 46) with occluded coronary arteries (100%). It was revealed that the flow rate (Q, ml/min) in group one was lower (17±3.1) than in group two (33±5.3) and group three (45±3.4). Also, differences were revealed in the resistance index of the grafts: it turned out to be higher in group one (5.2±1.1) and group two (4.5±0.9) as compared with group three (1.8±0.5). However, there was no between-group difference in diastolic filling of the grafts, which amounted to 58±13, 61±10 and 64±9% for groups one, two and three, respectively. By the shape of the curve, we assessed the reverse systolic peak whose presence prevailed in the grafts of group one (15 of 47; 31.9%) and group two (11 of 42; 26.2%) as compared with that in the grafts of group three (5 of 46; 10.8%). The obtained findings confirm higher frequency of the presence of competitive blood flow in the grafts used on non-occluded coronary arteries.

[Perfusion-Metabolic Myocardial Scintigraphy in Prognosis of Left Ventricular Remodeling After Complex Surgical Treatment of Ischemic Cardiomyopathy].

PURPOSE: To study capabilities of perfusion-metabolic myocardial scintigraphy for prediction of the left ventricular (LV) reverse remodeling after comprehensive surgical treatment of ischemic cardiomyopathy (ICMP). METHODS: The study included ICMP patients aged 56±7 years (n=32) who underwent surgical correction of LV dysfunction (myocardial revascularization, LV reconstruction, and mitral valve restoration). Inclusion criteria were significant coronary artery disease; myocardial infarction; New York Heart Association (NYHA) class III-IV heart failure; LV ejection fraction (EF) ≤45%; LV end-systolic index (ESI) >60 mL/m2; and LV akinesia or dyskinesia according to echocardiography. Before surgery all patients were subjected to scintigraphy with 99mTc-MIBI (to assess perfusion) and with 123I-BMIPP (to assess myocardial metabolism). Scintigraphy results were expressed as median and lower; upper quartile (Me [lQ; hQ]). The clinical status and ventricular volume indicators were evaluated before surgery, in the early post-operative period (up to 4 weeks), and in the late post-operative period (12 months). RESULTS: At 12 months after intervention patients were divided into two groups: group 1 comprised patients (n=18) with beneficial outcome of the operation that stopped LV remodeling (ESI decreased, remained unchanged, or increased by.

[Bilateral Internal Mammary Grafts With Preservation of Sternum Blood Supply].

We have prospectively collected data from 43 patients who underwent coronary artery bypass surgery and received bilateral internal thoracic artery (ITA) graft. Left ITA was harvested on full length from ostium to bifurcation. Right ITA harvesting included mobilization of only its proximal stump (5-6 cm long), that allowed its distal segment to remain intact. Proximal stump of right ITA was lengthened by radial artery or large subcutaneous vein grafts in order to reach various parts of coronary vascular bed. After comparative intraoperative manometry of ante- and retrograde pressures in right ITA patients were divided into two groups. In group 1patients (n=28) difference between ante- and retrograde systolic pressure (112.5+/-17.4 and 92.4+/-19.6 mm Hg, respectively) was <30%; in group 2 patients (n=15) difference between ante- and retrograde pressure (110.2+/-14.1 and 68.9+/-12.3 mm Hg, respectively) was more or equal 30%. Lower limb and carotid (arteries stenotic lesions (stenosis >60-70%) were more frequent in group 2 (n=8; 18.6%) than in group 1 (n=4; 9%). However postoperative ultrasound study detected no significant differences between two groups in systolic retrograde blood flow velocity in intact portion of right ITA (29.8+/-8.7 and 23.1+/-8.0 cm/s, respectively, p>0.05). Absence of sternal wound healing complications confirmed efficacy of sternal retrograde blood supply through lower and upper epigastric arteries. Patency rate of composite grafts according to angiography (n=19) performed in 3+/-0.8 years after surgery was high (94.7%). Our data confirm high functionality of bilateral ITA grafts with preservation of sternal supply.

[Interrelation of Electrophysiological and Perfusion Changes in Patients With Left Ventricular Aneurysm].

The study was aimed at identification of relations between perfusion and electrophysiological changes in left ventricular (LV) myocardium in patients with ischemic heart disease (IHD) with postinfarction LV aneurysm and ventricular tachycardia. The study enrolled 23 patients with the aforementioned disease. Preoperatively, apart from standard clinical examination of cardiosurgical patients, intracardiac electrophysiological study and perfusion single-photon emission computed tomography of myocardium with 99mTc-Technetril were performed. The patients were subjected to coronary artery bypass grafting and left ventricular reconstruction. Assessment of the outcomes showed that electrophysiological condition of left ventricle was dependent on myocardial perfusion. Electrophysologically normal myocardium with electric potential >1.5 mV, transient zone (0.5-1.5 mV) and zones with the potential <0.5 mV differed significantly by the percentage of perfusion: 61, 45, and 35%, respectively. Zones of delayed conduction and those of double potential were located mostly in transient zone of electrical potential conduction with the current amplitude of 0.5-1.5 mV and myocardial perfusion from 35 to 61%. Double potential zone was formed in the area of myocardium with better perfusion (perfusion defect of 55% with preserved metabolism) as opposed to the zone of delayed conduction, where perfusion defect was 40% with low level of metabolic activity. The obtained data has proven the presence of correlation between electrophysiology and perfusion of myocardium. This provides an opportunity to identify electrically unstable myocardial zones with the help of specific computer tomography of myocardium.

[Modelling of Drosophila gap gene network under Bcd morphogen variation].

Expression patterns of segmentation genes are formed under the influence of maternal transcription factor gradients, which initiate spatially localized expression in the cascade of segmentation genes. Bcd is one of these activators. We have studied one model of regulation in the gap gene network by varying the concentration of this protein. We have shown that the known gap gene network topology is not sufficient to explain experimental data on the shifts exhibited by the hb anterior expression domain by change in Bcd concentration in the embryo. As the result of modeling with these experimental data taken into account, a new topology is obtained that determines the correct shifts of the hb expression domain. These results suggest that interactions among the three hb, Kr and gt genes are key regulatory factors for the valid behaviour of the hb expression pattern with Bcd concentration changes. This study made it possible to specify the limits of validity for phenomenological models of gene networks.

[Policy of using the right internal thoracic artery "in situ" for coronary artery bypass grafting].

The authors analysed the outcomes in a total of 73 patients subjected to coronary artery bypass grafting with the use of the "in situ" the right internal thoracic artery. Of these, 14 patients endured bypass grafting with assessment of the conformity of the length of the "in situ" right ITA as a conduit for the distal third of the right coronary artery (RCA). 16 patients underwent grafting of the RITA "in situ" with the RCA by passing through the pleural cavity. The remaining 43 patients were subjected to bilateral mammary composite bypass grafting using the radial artery (RA). A total of 22 segments of the RA were subjected to a comparative morphometric examination depending on the method of exposure. We additionally analysed 56 cases of utilizing the RA with the use of the pharmacological protocol of preventing spasm. The results were regarded statistically significant if p<0.05. We used the non-parametric criterion of Mann-Whitney. The obtained results showed that the right ITA "in situ" may be used for bypass grafting of the RCA system, excluding the risk of graft tension, if the perpendicular from the 6th intercostal space crosses the sharp edge of the heart 1.5-2 cm distal to the medial point, with the minimum number of complications after 1.5±0.3 years (7.1%). When the above-mentioned perpendicular is located proximal to the middle point of the sharp edge of the heart it is possible to use the right ITA "in situ" for the RCA system thanks to passing the conduit through the right pleural cavity under the anterior segment of the upper lobe and the medial segment of the middle lobe of the right lung with no complications after 1 year. The method of composite bypass grafting by means of the proximal segment of the right ITA "in situ" and the RA makes it possible to effectively revascularize any portions of the coronary bed (latency 94.7% after 3.0±0.8 years), to avoid manipulations on the aorta, and to save the bed of the right ITA in the middle and distal third of the sternum with no postoperative complications. It was revealed that in the conditions of decreased osmotic pressure the increase in the thickness of the vascular wall is more pronounced in the skeletonized segments of the RA (1.38±0.05 mm) as compared with the segments surrounded by connective and fatty tissue (1.09±0.04 mm). The pharmacological protocol for prevention of radial artery spasm used in 56 patients resulted in a small number of complications observed after 3.0±0.8 years (myocardial infarctions - 1.75%, angina pectoris relapse - 7%). Hence, the developed methods of using the right ITA "in situ" widen possibilities of bilateral mammary bypass grafting, excluding the existing problems of routine use of the both ITAs "in situ".

[Fasciotomy as a method of surgical preparation of a conduit for coronary artery bypass grafting].

The study included a total of 59 patients undergoing coronary artery bypass grafting with the use of the radial artery (RA). Group One consisted of 28 patients who while preparing the conduit were subjected to longitudinal dissection of the fascial compartment (fasciotomy) of the RA. Group Two comprised 31 patients not undergoing fasciotomy. In Group One patients prior to fasciotomy, 2 segments were cut off from each RA and incubated in a hypo osmotic solution either in the fascial compartment (n=28) or after fasciotomy (n=28) followed by morphometric analysis. Therapeutic results in all patients were studied averagely 3.3 ± 0.8 years after surgery. 32 patients underwent control coronary bypass angiography averagely 2.5 ± 0.54 years after the operation. The morphometric analysis of the RA segments in conditions of simulated oedema revealed that a more pronounced decrease in the RA lumen (by 49.7%) was observed in the segments kept in the fascial compartment as compared with the segments after fasciotomy (1.08 ± 0.12 mm and 2.21 ± 0.09 mm, respectively, p=0.0129). In the remote period after the operation (mean 3.3 ± 0.8 years) Group One patients were found to have fewer cases of renewal and increase of the angina class (n=3; 10.7%) than Group Two patients (n=7; 22.5%; p=0.0289). There were no cases of secondary myocardial infarction in Group One patients, whereas in Group Two there were 2 (6.5%) cases of myocardial infarction in the postoperative period. Based on the findings of coronary bypass angiography, patency of the RA in Group 1 was higher than in Group 2 (91.6 and 78.6%, respectively; p=0.0371). The obtained results are suggestive that fasciotomy of the RA during surgical preparation of the conduit is appropriate, thus decreasing the risk of blood flow reduction via the arterial bypass graft and improving the outcomes of autoarterial coronary bypass grafting.

Scale invariance and universality in a cold gas of indirect excitons.

We address, theoretically, the puzzling similarity observed in the thermodynamic behavior of independent clouds of cold dipolar excitons in coupled semiconductor quantum wells. We argue that the condensation of self-trapped exciton gas starts at the same critical temperature in all traps due to the specific scaling rule. As a consequence of the reduced dimensionality of the system, the scaling parameters appear to be insensitive to disorder.

[Biophysical modeling of dose response for γ-ray induced complex chromosomal aberrations].

Experiments with FISH painting of chromosomes, including full-color mFISH, have revealed unexpectedly high yields of complex chromosomal aberrations (CA). The ratio of complex and simple aberrations observed in the 1st postirradiation mitosis has proved to depend on the cell line, LET and time after irradiation in a complicated way. According to the widely accepted viewpoint, interchanges are formed as a result of interaction between either contacting lesions or those having come into contact on a boundary between chromosome territories. However, the theoretical analysis has shown that the mechanism of CA formation at the boundary between chromosome territories is insufficient to explain the high ratio of complex/simple aberrations induced by γ-rays in human lymphocytes at different doses. In the present work, the origin of high yields of complex CA is investigated by means of biophysical modeling. The hypothesis that CA are formed on nuclear centers is able to explain quantitatively the dose response relationships for both simple and complex interchanges observed by mFISH technique after low-LET irradiation.

[Radiation-induced changes in structural state of membranes of human blood cells].

To evaluate radiation-induced changes in the structural state of the membranes, blood samples of healthy donors were subjected to gamma radiation in the range of small (1-10 cGy) and medium doses (50 cGy-2 Gy). After irradiation, the microviscosity of lipid membranes of red and white blood cells was measured by ESR spin probe method. At doses exceeding 1 cGy, statistically significant changes of the degree of spontaneous erythrocyte hemolysis and of the lymphocyte plasma membrane microviscosity were observed. Under identical irradiation conditions, the stability of lymphocyte membranes was less as compared to erythrocyte membranes.

Thermodynamic model of the macroscopically ordered exciton state.

We explain the experimentally observed instability of cold exciton gases and the formation of a macroscopically ordered exciton state in terms of a thermodynamic model accounting for the phase fluctuations of the condensate. We show that the temperature dependence of the exciton energy exhibits fundamental scaling behavior with the signature of the second order phase transition.

Optical pump-probe detection of manganese hyperfine beats in (Cd,Mn)Te crystals.

Optical pump-probe experiments reveal spin beats of manganese ions in (Cd,Mn)Te, due to hyperfine and crystal fields. At "magic" orientations of the magnetic field, the effect of local crystal field is strongly suppressed. In this case, the spin precession of Mn(2+) embedded in the lattice approaches the precession expected for the free ion. Following optical excitation, regular spin pulses show up, revealing the one-to-one correspondence between precession frequency and Mn(2+) nuclear spin state. The period of the spin pulses accurately determines the hyperfine constant |A|=705 neV. The manganese spin coherence time up to T(2)(Mn)≃15 ns is measured for a manganese concentration x=0.0011.