[Prevention of eventration in diffuse suppurative processes in small pelvis]

The study was devoted to the problem of postoperative eventrations in gynaecological practice. Coaptation removable sutures were applied in order to prevent similar complications. Operations were performed in the cases of desolate condition of purulent disease of the uterus and uterine appendages with diffuse suppurative peritonitis. An advanced operative technique of suturing through all layers of abdominal wall demonstrated its high efficacy. No one patient (from 39) had the eventration or wound abscess.

[Dependence of the efficiency of cell growth on biosynthetic medical materials on the microstructure of their surface]

The efficiency of a novel class of biosynthetic wound dressings in wich natural and synthetic polymeric components are not arranged in layers but are in a unified structure, i. e., form a new composite material, has been studied. In particular, we tried to determine whether the interactions of dressing surface with cells of the injured tissue and/or culture grown in vitro depend on the microstructure of the surface. The efficiency of cell growth was considered in terms of the stimulation of cell growth. The microstructure of the surface was examined using the scanning electron microscopy at high resolution. The results of the study have shown that the structure of biosynthetic dressings depends on the variations in the composition and the ratio of the components. The role of the microstructure of the dressing in the effectiveness has been demonstrated. The factors which have the most significant effect on the regenerating properties of the wound dressings have been revealed.

Methodology for estimating cancer risks of diagnostic medical exposure: with an example of the risks associated with computed tomography

Because of fast growing medical radiation use, estimating possible late health effects of radiation, including potential cancer risk, is an issue of substantial interest. Since physicians make the decision to order or perform a radiological procedure, it is very important to provide them with objective information about possible radiation-associated risks. Methodology for estimating cancer risks based on recommendations of ICRP Publication 103 is presented in the paper. Organ doses, age, and gender are used as basic parameters. An example of the evaluation of radiation-associated risks from computed tomography examination is presented.

Formation of potential radiation risk groups to render timely targeted medical care: lessons of Chernobyl

The paper discusses technology for establishing potential cancer risk groups, based on methods of molecular and radiation epidemiology. Assay of gene mutations at the T-cell receptor (TCR) locus as the method of molecular epidemiology was used for measuring the frequency of TCR-mutations in 320 nuclear workers of the Institute of Physics and Power Engineering (IPPE). The method of radiation epidemiology was applied to the estimation of attributable risk fraction (ARF) for solid cancers in these groups. The main estimates of radiation risk after the Chernobyl accident are in close agreement with the International Commission on Radiological Protection (ICRP) Publication, 103 models published in 2007. In nuclear workers of the IPPE with ARF ≥ 10%, the increased level of TCR-mutations occurs more often (risk ratio=9.7; 95% CI: 2.9; 32.1).

Radiation-epidemiological studies of thyroid cancer incidence in Russia after the Chernobyl accident (estimation of radiation risks, 1991-2008 follow-up period)

This study presents an analysis of the thyroid cancer incidence in the population of the most contaminated territories of Bryansk, Kaluga, Oryol and Tula oblasts affected by the Chernobyl accident. The follow-up period is 1991-2008, and the cohort size is 309 130 people. For that period 978 thyroid cancer cases were detected. The excess relative risk per 1 Gy (ERR/Gy) is found to be statistically significant for children and adolescents (0-17 y of age) at the time of the Chernobyl accident (ERR/Gy=3.22; 95 % confidence interval (1.56; 5.81). In boys, the ERR/Gy was higher than in girls -6.54 and 2.24, respectively. A statistically significant decrease in ERR/Gy with time since exposure, by a factor of 0.37 per 10 y, was observed for the whole cohort and for boys separately, but not for girls. No radiation risks of a thyroid cancer among people of 18 y of age at exposure and older were found.

Leukemia incidence in the Russian cohort of Chernobyl emergency workers

Of all potentially radiogenic cancers, leukemia, a type of cancer of the blood, has the highest risk attributable to ionizing radiation. Despite this, the quantitative estimation of radiation risk of a leukemia demands studying very large exposed cohorts, because of the very low level of this disease in unexposed populations and because of the tendency for its radiation risk to decrease with time. At present, the Japanese cohort of atomic bomb survivors is still the primary source of data that allows analysis of radiation-induced leukemia and the underlying dose-response relationship. The second large cohort that would allow to study radiation-induced leukemia is comprised of individuals who were exposed due to the accident of the Chernobyl nuclear power plant in 1986. The objective of the present study was to estimate radiation risks of leukemia incidence among the Russian cohort of Chernobyl emergency workers, for different time periods after the accident. Twenty-five years after the Chernobyl accident and based on the results of the present study, one can conclude that the radiation risk of leukemia incidence derived from the Russian cohort of Chernobyl emergency workers is similar to that derived from the cohort of atomic bomb survivors: The time-averaged excess relative risk per Gray (ERR Gy(-1)) equals 4.98 for the Russian cohort and 3.9 for the life span study (LSS) cohort; excess absolute risk decreases with time after exposure at an annual rate of 9% for the Russian cohort, and of 6.5% for the LSS cohort. Thus, the excess in risk of leukemia incidence in a population due to a single exposure is restricted in time after exposure by the period of about 15 years.

Lessons from Chernobyl and prognosis for Fukushima: radiological consequences

The following are considered: results of large-scale radiation epidemiological studies of the health effects of the Chernobyl accident, radiation risks for emergency workers and the affected population; and verification of ICRP risk models taking into account data on the Chernobyl accident and preliminary prognostic estimates of potential radiological consequences of the Fukushima disaster.

[Nanocrystaline ceria based materials--perspectives for biomedical application]

Nanocrystalline ceria possesses a unique complex of physical and chemical properties making it highly bioactive material. In this review, modern data on the action of nanocrystalline ceria on cells, micro- and macroorganisms are analyzed. Special attention is paid to the analysis of the factors affecting protective properties of CeO2 with respect to the living systems.

[Investigation of anti-inflammatory action of electromagnetic irradiation of extremely high frequencies in experiment]

There were studied some mechanisms of the effect realization of the extremely high frequency electromagnet irradiation, including modification of the organism immune status as an answer on the irradiation action, manifested by mobilization of ripe CD4+ and CD8+ T-lymphocytes, the interleukins (IL) concentration enhancement, including, IL-1, IL-10, as well as the levels lowering of IL-6 and C-reactive protein in the blood serum. There was established, that using a switching on the intermediate signal systems it is possible to induce the directed (antiinflammatory) answer of organism towards the effective parameters of electromagnet irradiation.

[Mortality among the liquidators of the Chernobyl accident: dose dependences and groups of the potential risk]

Dynamics of the mortality and the mortality radiation risks among male emergency workers of 1986-1987 years of entrance to the Chernobyl zone is analyzed. The average dose of external gamma-exposure for this cohort equals 128 mGy. The size of the cohort at the beginning of the follow-up in 1992 was 47820 persons. For the follow-up period 1992-2006 statistically significant radiation risks of death rates have been estimated: for the mortality from all causes, the excess relative risk per Gy (ERR/Gy) equals 0.42 with 95% confidence interval (95% CI) (0.14-0.72); for the mortality from solid cancers ERR/Gy = 0.74, 95% CI (0.03-1.76); and for the mortality from the circulatory system diseases ERR/Gy = 1.01, 95% CI (0.51-1.57). Based on these estimates the risk groups were ranked among all Russian emergency workers (160 thousand persons): the group of the potential radiation risk with doses more than 150 mGy (33488 persons) and the group of the high radiation risk with doses more than 240 mGy (6054 persons).

[Investistigation of the role of heterogenety individual radiosensitivity in estimation of radiation indused ageing]

The influence of heterogeneity in individual radiosensitivity on estimation of ageing using survival curve is considered. Quadratic deviation of the rate of ageing from the true value in estimated by imitation modeling techniques. The Gompertz model for spontaneous mortality and gamma-frailty model for heterogeneity are used. Simulation performed at different values of radiation effect and heterogeneity variance. It is shown that inclusion heterogeneity in the model is not efficient for large values of heterogeneity variance. For moderate values of heterogeneity variance model with heterogeneity produces more accurate results in comparison with the model without heterogeneity.

[Antiviral effect of cerium dioxide nanoparticles stabilized by low-molecular polyacrylic acid]

Antiviral activity of nanosize cerium dioxide sols (CeO2) in animal cell culture has been studied. The inhibiting effect of the mentioned sols upon reproduction of vesicular stomatitis test-virus was demonstrated for the first time in case of preliminary 24-hour contact with cells lines L929 and EPT. The effectiveness of protective action depends on initial precursor and the way of obtained water nanosize nanosols.

Latent period in induction of radiogenic solid tumors in the cohort of emergency workers

The paper presents estimates for the latent period of the induction of radiogenic solid cancers among Chernobyl emergency workers (males) living in six central regions of Russia. The analysis is based on medical and dosimetry data gathered by the National Radiation and Epidemiological Registry over the time period from 1986 to 2005. The cohort includes 59,770 persons who stayed in the exposure zone (30-km zone around the Chernobyl nuclear power plant) in 1986-1987. There were 2,718 cases of solid tumors identified during the follow-up time in this cohort. The mean radiation dose in the cohort is 0.13 Gy. The radiation risk and latent period were estimated using the method of maximum likelihood. The excess relative risk per unit dose was found to be 0.96 (95% confidence interval (CI): 0.3-1.7) and the minimum latent period for induction of solid tumors is 4.0 years (95% CI: 3.3-4.9).

Estimation of individualized radiation risk from chronic occupational exposure in Russia

Internationally, the upper limit of acceptable individualized risk from occupational exposure for nuclear industry workers is determined by the death probability 10(-3) y(-1). The same risk value of 10(-3) y(-1) is established by the radiation safety standards currently in force in Russia. The United Nations Scientific Committee on the Effects of Atomic Radiation has proposed the formulas for estimating individualized risk of developing cancer with allowance for radiation dose, age at exposure, attained age, and sex. This methodology is first applied to estimate individualized radiation risk for Russian nuclear industry workers (49,900 persons) who were monitored for radiation exposure through the use of personal dosimeters. The estimates show that in 2006 the threshold of 10(-3) y(-1) for individualized risk is exceeded for 755 persons, which is 1.6% of all workers covered by personal dose monitoring. The excess absolute risk (EAR) and attributable risk (AR) were estimated for all cancers, solid cancers, and leukemias.

Polymorphisms of DNA damage response genes in radiation-related and sporadic papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) etiologically occurs as a radiation-induced or sporadic malignancy. Genetic factors contributing to the susceptibility to either form remain unknown. In this retrospective case-control study, we evaluated possible associations between single-nucleotide polymorphisms (SNPs) in the candidate DNA damage response genes (ATM, XRCC1, TP53, XRCC3, MTF1) and risk of radiation-induced and sporadic PTC. A total of 255 PTC cases (123 Chernobyl radiation-induced and 132 sporadic, all in Caucasians) and 596 healthy controls (198 residents of Chernobyl areas and 398 subjects without history of radiation exposure, all Caucasians) were genotyped. The risk of PTC and SNPs interactions with radiation exposure were assessed by logistic regressions. The ATM G5557A and XRCC1 Arg399Gln polymorphisms, regardless of radiation exposure, associated with a decreased risk of PTC according to the multiplicative and dominant models of inheritance (odds ratio (OR) = 0.69, 95% confidence interval (CI) 0.45-0.86 and OR = 0.70, 95% CI 0.59-0.93 respectively). The ATM IVS22-77 T > C and TP53 Arg72Pro SNPs interacted with radiation (P = 0.04 and P = 0.01 respectively). ATM IVS22-77 associated with the increased risk of sporadic PTC (OR = 1.84, 95% CI 1.10-3.24) whereas TP53 Arg72Pro correlated with the higher risk of radiogenic PTC (OR = 1.80, 95% CI 1.06-2.36). In the analyses of ATM/TP53 (rs1801516/rs664677/rs609429/rs1042522) combinations, the GG/TC/CG/GC genotype strongly associated with radiation-induced PTC (OR = 2.10, 95% CI 1.17-3.78). The GG/CC/GG/GG genotype displayed a significantly increased risk for sporadic PTC (OR = 3.32, 95% CI 1.57-6.99). The results indicate that polymorphisms of DNA damage response genes may be potential risk modifiers of ionizing radiation-induced or sporadic PTCs.

Risk of thyroid cancer among Chernobyl emergency workers of Russia

The presented paper deals with the thyroid cancer incidence in selected cohorts of emergency workers of Russia. In 1986-2003, a total of 87 cases of thyroid cancer were observed. Based on these data, a statistically significant increase in thyroid cancer incidence was found above the reference level for the male population of Russia, corresponding to a standardized incidence rate (SIR) of SIR = 3.47 [95% confidence interval (CI): 2.80; 4.25]. The highest incidence rate (SIR = 6.62, 95% CI: 4.63; 9.09) was shown for those emergency workers who took part in the early recovery operations in April-July 1986. The estimated SIR value increases to 7.97 (95% CI: 5.24; 11.52) after allowing for a 10 years latent period of Chernobyl-related thyroid cancers. These results indicate that the exposure to incorporated (131)I was the major risk factor of thyroid cancer among Chernobyl emergency workers. No statistically significant relationship was found for the thyroid cancer incidence and external radiation dose.

Late cancer and noncancer risks among Chernobyl emergency workers of Russia

The presented work summarizes data on estimated radiation risks among Chernobyl emergency workers of the Russian Federation. In 1991-1998, the excess relative risk (ERR) of death from malignant neoplasm was statistically significant: excess relative risk per 1 Gy (ERR/Gy)=2.11 with 95% confidence interval (CI) (1.31-2.92). In 1991-2001, the ERR estimation for incident solid cancers gives a positive, but statistically insignificant value: ERR/Gy=0.34 with 95% CI (-0.39; 1.22). In 1986-2003, radiation risk for leukemia incidence was investigated. During the first 10 y after the Chernobyl accident (1986-1996) the relative risk (RR) of leukemia (excluding chronic lymphocytic leukemia) was statistically significant: RR=2.2 with 95% CI (1.3-3.8) for emergency workers with doses>0.15 Gy in comparison with less exposed workers. In 1986-2000, a statistically significant dose response was observed for incident cerebrovascular diseases: ERR/Gy=0.39, 95% CI=(0.004; 0.77). For doses>0.15 Gy a statistically significant risk of cerebrovascular diseases as a function of mean daily dose was observed: ERR per 0.1 Gy d(-1)=2.17 with 95% CI=(0.64; 3.69). Different but overlapping cohorts of Russian emergency workers were used for these estimations. No adjustments were made for recognized risk factors for cerebrovascular diseases. All results should be considered as preliminary.

[Thyroid cancer incidence among Chernobyl emergency workers: follow-up period 1986-2003]

A vast amount of research articles devoted to the increase in childhood thyroid cancer incidence in the most contaminated by radionuclides territories of Belarus, Russia and Ukraine affected by the Chernobyl accident were published recent years. However, the amount of research studies of thyroid cancer incidence among the Chernobyl emergency workers (liquidators) is quite scanty. In the article results of the study of thyroid cancer incidence in the cohort of the Chernobyl liquidators (103427 persons) residing in 6 administrative regions of Russia (North-West, Volgo-Vyatsky, Central-Chernozemny, Povolzhsky, North-Caucasus and Urals) are described and discussed. For the period 1986-2003 eighty seven cases of thyroid cancer were detected in the cohort. Statistically significant excess of the incidence among liquidators over baseline incidence, SIR = 3.39 (95% CI: 2.73; 4.16), among men of Russia has been found. The highest thyroid cancer incidence (SIR = 6.49) was registered among liquidators who had been involved in mitigation works during April-July 1986. At the same time no statistically significant relationship between the incidence rate and external radiation dose, ERR = 1.68 (95% CI: -0.95; 6.46), was detected.

Concept of optimisation of the radiation protection system in the nuclear sector: management of individual cancer risks and providing targeted health care

The paper discusses the provision of targeted health care to nuclear workers in Russia based on radiation-epidemiological estimates of cancer risks. Cancer incidence rates are analysed for the workers of the Institute of Physical Power Engineering (the first nuclear installation in the world) who were subjected to individual dosimetric monitoring from 1950 to 2002. The value of excess relative risk for solid cancers was found to be ERR Gy(-1) = 0.24 (95% CI: -4.22; 7.96). It has been shown that 81.8% of the persons covered by individual dosimetric monitoring have potential attributive risk up to 5%, and the risk is more than 10% for 3.7% of the workers. Among the detected cancer cases, 73.5% of the individuals show an attributive risk up to 5% and the risk is in excess of 10% for 3.9% of the workers. Principles for the provision of targeted health care, given voluntary health insurance, are outlined.

[The identification of potential radiation risk groups in case of chronical occupational exposure: individual cancer risks among the industrial firm "Maiak" personnel]

The draft new recommendations of the ICRP emphasize the need for transition from the collective dose to the dose matrix concept with optimization of the radiation protection system. In fact, this means assessment of the attributive (radiation-induced) risk at individual level with allowance for the dynamics of dose accumulation during the whole length of professional experience. The work provides assessments for high potential risk group from the "Mayak" personnel based on the dose matrix and using the UNSCEAR technique for assessing the attributive risk. It was found that about 2% of "Mayak" personnel subject to individual dosimetric monitoring in 2005 can be attributed to this group.

The role of intermediate state polarization in determination of vector properties of the ground state using multiphoton excitation

We present a general theory for calculating the vector and geometrical properties of the multiphoton excitation of an arbitrary atomic or molecular system. The results are applied to study the influence of the polarization of the two-photon excited state, which is usually neglected, on the intensity of (2 + 1) resonant multiphoton ionization in atoms. Two examples of specific atomic systems of practical importance are presented: oxygen and chlorine. For some cases, the effect of the polarization of the pre-ionized state can be significant and must be properly treated.

Radiation-epidemiological studies of thyroid cancer incidence among children and adolescents in the Bryansk oblast of Russia after the Chernobyl accident (1991-2001 follow-up period)

In this study, thyroid cancer incidence (follow-up period: 1991-2001) has been analyzed, including persons who were exposed as children at an age between 0 and 17 years and who are living in the Bryansk oblast, the worst contaminated area of Russia after the Chernobyl accident. According to the census of 1989, the population of this oblast comprises 375 thousand people. Thyroid doses from incorporated radioiodine isotopes -- both for the thyroid cancer cases and the study population -- were determined based on the official methodology approved by the Russian Scientific Commission on Radiation Protection. Between 1991 and 2001, a total of 199 thyroid cancer cases were diagnosed at cancer centers (the so-called oncological dispensaries) of the investigated regions. The performed analysis relies on medical and dosimetric information available from the Russian National Medical and Dosimetric Registry which was established after the Chernobyl accident. Diagnoses were confirmed histologically for 95% of the cases. The analysis described revealed statistically significant radiation risk only for those exposed as children at an age of 0-9 years. In this group, the standardized incidence ratio (the national incidence rate was used as a reference) in the considered time period is estimated to be 6.7 (5.1, 8.6 95%CI) and 14.6 (10.3, 20.2 95%CI) for girls and boys, respectively. The risk dependence on age at exposure has also been studied. It has been shown that the smaller the age the higher the risk. For girls whose age at exposure was 0-4 years, the excess relative risk per 1 Gy for the period 1991-2001 was 45.3 (5.2, 9,953 95%CI; with internal control) and 28.8 (4.3, 2,238 95%CI; with external control), respectively. For boys whose age at exposure was 0-9 years the corresponding excess relative risk per 1 Gy was 68.6 (10.0, 4,520 95%CI) and 177.4 (-276, 10(6) 95%CI), respectively. Dependence of radiation risk on time was studied, with the focus on two follow-up periods 1991-1996 and 1997-2001, respectively. In 1997-2001 the radiation risk is shown to decrease among girls, and increase among boys.