Relationship between follow-up periods and the low-dose ranges with statistically significant radiation-induced risk of all solid cancers in the Russian cohort of Chernobyl emergency workers.

Radiation-induced risks for all solid cancer incidence and mortality were studied in the cohort of Russian Chernobyl emergency workers. The cohort included 69,440 persons with documented individual radiation dose accrued over the time of working in the Chernobyl zone. The mean age at entry into the zone of recovery operations was 33.9 years and accumulated radiation dose was 132.9 mGy. A total of 6981 solid cancer incident cases and 4272 deaths occurred in this cohort from 1992 to 2017. Three follow-up periods were studied: 1992-2009, 1992-2013, and 1992-2017. For each follow-up period, the lowest dose range with statistically significant (p < 0.05) radiation-induced risk of all solid cancer incidence and mortality were obtained. For the incidence of all solid cancer during the follow-up period 1992-2009, this lowest dose range was estimated to be 0-250 mGy with an excess relative risk per dose of ERR Gy-1 = 0.51 and 95% confidence interval (CI) (0.02; 1.05) Gy-1. For the period 1992-2013, the lowest dose range was 0-175 mGy with ERR Gy-1 = 0.85 (95% CI 0.03; 1.78), while for the whole follow-up period 1992-2017, it was 0-175 mGy with ERR Gy-1 = 0.81 (95% CI 0.08; 1.62). For mortality from all solid cancers during the follow-up period 1992-2009, the lowest dose range with statistically significant radiation-induced risk was estimated to be 0-225 mGy with ERR Gy-1 = 1.07 (95% CI 0.31; 0.97). For the period 1992-2013, the lowest dose range was 0-225 mGy with ERR Gy-1 = 0.86 (95% CI 0.23; 1.58), while for the whole follow-up period 1992-2017, the lowest dose range was 0-200 mGy with ERR Gy-1 = 0.82 (95% CI 0.10; 1.65). Thus, it was found that the minimal level of significant exposure (Dmin), for which a statistically significant radiation-induced risk of all solid cancers was obtained for Russian emergency workers (with individual doses of 0 - Dmin), decreases with increasing duration of cohort observation, both for cancer incidence and mortality.

Radiation Risk of Cardiovascular Diseases in the Cohort of Russian Emergency Workers of the Chernobyl Accident.

This paper continues a series of publications that analyze the impact of radiation on incidence of circulatory system diseases in the cohort of Russian recovery operation workers (liquidators) and presents the results of the analysis of cardiovascular disease (CVD) incidence. The studied cohort consists of 53,772 liquidators who arrived in the Chernobyl accident zone within the first year after the accident (26 April 1986 to 26 April 1987). The individual doses varied from 0.0001 Gy to 1.42 Gy, and the mean external whole body dose in the cohort was 0.161 Gy. A total of 27,456 cases of CVD were diagnosed during the follow-up period 1986-2012 as a result of annual health examinations. A Poisson regression model was applied to estimate radiation risks and other risk factors associated with CVD. The following factors were identified as risk factors for CVD: the dose, duration of the liquidators' work in the Chernobyl zone, and concomitant diseases (diabetes mellitus, hypertension, overweight, and alcohol dependence). The baseline incidence of CVD is statistically significantly (p < 0.001) associated with all studied concomitant diseases. The incidence of CVD has revealed a statistically significant dose response with the lack of a latent period and with the average ERR Gy = 0.47, 95% CI = 0.31, 0.63, p < 0.001. Radiation risks of CVD statistically significantly (p = 0.01) varied with the duration of liquidators' stay in the Chernobyl zone; for those who stayed in the Chernobyl zone less than 6 wk, ERR/Gy = 0.80, 95% CI = 0.53; 1.08, p < 0.001.

[Non-Parametric Analysis of Radiation Risks of Mortality among Chernobyl Clean-Up Workers].

Analysis of the relationship between dose and mortality from cancer and circulation diseases in the cohort of Chernobyl clean-up workers based on the data from the National Radiation and Epidemiological Registry was performed. Medical and dosimetry information on the clean-up workers, males, who got radiation doses from April 26, 1986 to April 26, 1987, which was accumulated from 1992 to 2012, was used for the analysis. The total size of the cohort was 42929 people, 12731 deaths were registered in the cohort, among them 1893 deaths from solid cancers and 5230 deaths were from circulation diseases. An average age of the workers was 39 years in 1992 and the mean dose was 164 mGy. The dose-effect relationship was estimated with the use of non-parametric analysis of survival with regard to concurrence of risks of mortality. The risks were estimated in 6 dose groups of similar size (1-70, 70-130, 130-190, 190-210, 210-230 and.230-1000 mGy). The group "1-70 mGy" was used as control. Estimated dose-effect relationship related to cancers and circulation diseases is described approximately with a linear model, coefficient of determination (the proportion of variability explained by the linear model) for cancers was 23-25% and for circulation diseases - 2-13%. The slope coefficient of the dose-effect relationship normalized to 1 Gy for the ratio of risks for cancers in the linear model was 0.47 (95% CI: -0.77, 1.71), and for circulation diseases it was 0.22 (95% CI: -0.58, 1.02). Risks coefficient (slope coefficient of excess mortality at a dose of 1 Gy) for solid cancers was 1.94 (95% CI: - 3.10, 7.00) x 10(-2) and for circulation diseases it was 0.67 (95% CI: -9.61, 11.00) x 10(-2). 137 deaths from radiation-induced cancers and 47 deaths from circulation diseases were registered during a follow up period.

Radiation-epidemiological Study of Cerebrovascular Diseases in the Cohort of Russian Recovery Operation Workers of the Chernobyl Accident.

The paper presents an analysis of the incidence of cerebrovascular diseases (CeVD) in the cohort of Russian workers involved in recovery tasks after the Chernobyl accident. The studied cohort consists of 53,772 recovery operation workers (liquidators) who arrived in the zone of the Chernobyl accident within the first year after this accident (26 April 1986-26 April 1987). The mean external whole body dose in the cohort was 0.161 Gy, while individual doses varied from 0.0001 Gy to 1.42 Gy. During the follow-up period 1986-2012, a total of 23,264 cases of CeVD were diagnosed as a result of annual health examinations. A Poisson regression model was applied for estimation of radiation risks and for an assessment of other risk factors of CeVD. The following factors were considered as risk factors for CeVD: the dose, duration of the liquidators' work in the Chernobyl zone, and the concomitant diseases (hypertension, ischemic heart disease, atherosclerosis, and diabetes). The baseline incidence of CeVD is statistically significantly (p < 0.001) associated with all studied concomitant diseases. The incidence of CeVD has revealed a statistically significant dose response with the lack of a latent period and with the average ERR/Gy = 0.45, 95% CI: (0.28, 0.62), p < 0.001. Radiation risks of CeVD statistically significantly (p = 0.03) varied with the duration of liquidators' stay in the Chernobyl zone; for those who stayed in the Chernobyl zone less than 6 wk, ERR/Gy = 0.64, 95% CI = (0.38; 0.93), p < 0.001. Among studied concomitant diseases, diabetes mellitus statistically significantly (p = 0.002) increases the radiation risk of CeVD: for liquidators with diagnosed diabetes, ERR/Gy = 1.29.

Incidence and mortality of solid cancer among emergency workers of the Chernobyl accident: assessment of radiation risks for the follow-up period of 1992-2009.

This paper presents the results of a retrospective cohort study of cancer incidence and mortality among emergency workers of the Chernobyl accident, for the follow-up period 1992-2009. The cohort selected for analysis consists of 67,568 emergency workers who worked in the Chernobyl exclusion zone in 1986-1987. External radiation whole-body absorbed dose varied from 0.0001 gray (Gy) to 1.24 Gy, with a median of 0.102 Gy. Over the follow-up period 1992-2009, a total of 4,002 solid cancers of different sites were identified as the result of annual compulsory health examination, and a total of 2,442 deaths from all solid cancers in the study cohort were reported. Poisson regression was applied for the analysis of cancer incidence and mortality. The analysis of the standardized incidence ratio (SIR) has shown a statistically significant increase in cancer incidence in the cohort as compared with baseline cancer incidence among males of Russia. The average excess over the entire follow-up period is 18 % [SIR = 1.18, 95 % confidence interval (CI) 1.15; 1.22]. In contrast, however, no increase in the mortality from all cancers among the emergency workers as compared to the baseline mortality in Russian men was found. Values of excess relative risk of cancer incidence and mortality per 1 Gy (ERR Gy(-1)) are 0.47 (95 % CI 0.03; 0.96, p value = 0.034) and 0.58 (95 % CI 0.002; 1.25, p value = 0.049), respectively. These values are statistically significant.

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.

Exposure levels for persons involved in recovery operations after the Chernobyl accident. Statistical analysis based on the data of the Russian National Medical and Dosimetric Registry (RNMDR).

We present a detailed description of dosimetric data entered in the Russian National Medical and Dosimetric Registry (RNMDR) for emergency workers (liquidators) involved in recovery operations (RO) after the Chernobyl accident. The data on the absorbed doses from external exposure are based on the documents given to liquidators by organizations that performed dosimetric monitoring in the zones of operation. Using the data on external doses currently available in the RNMDR for 119,416 liquidators (78.4% of the total number of 152,325 persons), different statistical characteristics were derived to assess the reliability of the information. The paper also discusses dose distributions according to the date of beginning work in the RO zone [up to 250 km from the Chernobyl nuclear power plant (NPP)], on the distance of the settlement where the liquidators were accommodated or worked from the NPP, and on the duration of their stay in the RO zone. To analyse the reliability of the dosimetric data, the notion of an effective exposure dose rate (EEDR), i.e. the ratio of the dose registered in RNMDR and the duration of stay in the RO zone, was introduced for each liquidator, and corresponding statistical characteristics for the distribution of EEDR depending on the date of entry into the RO zone and distance from the place of residence or work to the NPP were obtained. The analysis for different groups of liquidators shows that the dosimetric information of the RNMDR is, as a statistical aggregate, generally consistent with the data on the radiation situation in the RO zones.

[The neurophysiological indices of neurotic patients with different types of individual character and their dynamics during group psychotherapy]. / Neirofiziologicheskie pokazateli u bol'nykh nevrozami s razlichnymi tipami aktsentuatsii kharaktera i ikh dinamika v protsesse gruppovoi psikhoterapii.

Based on the clinical and neurophysiological studies analysis is made of the prognostic importance of character accentuations as the most important factor of the personality premorbid condition of neurotic patients. 107 patients with different patterns of neuroses, who underwent group psychotherapy (a personality-oriented (reconstructive) variety). Analysis of the dynamics of the neurophysiological characteristics, made during group psychotherapy, supported the clinical data on varying curability of neurotic patients with different types of character accentuations. Patients with the hysteroid type character accentuation appeared more resistant to psychotherapy. In patients with the sthenic variety of hysteroid accentuation, the positive dynamics was recorded in but 30% of cases, in the asthenic variety of hysteroid accentuation, in 48.6% of cases. Patients with inhibited character traits turned out more pliable to group therapy. In the sensitive type accentuation, the positive dynamics of the neurophysiological characteristics was established in 65% whereas in psychasthenic accentuation, in 72% of cases. The neurophysiological correlations of the main types of character accentuations and their dynamics during group psychotherapy were also revealed.

[Characteristics of slow electrical potentials in healthy subjects and in patients with various forms of neuroses]. / Osobennosti élektricheskikh medlennykh potentsialov u zdorovykh i bol'nykh s razlichnymi formami nevrozov.

The shapes of the slow brain potentials--conditioned negative wave (CNW) and postimperative negative wave (PNW)--were compared in normal and neurotic subjects. Instruction-directed performance was used to investigate the physiological mechanisms of neuroses and to develop the diagnostic psychophysiologic tests with simultaneous recording of the slow potentials. These were evaluated by calculation of asymmetry and power amplification coefficients for CNW and PNW while more and more complicated instructions were given.

[Isolation of influenza virus with the antigenic formula Hav4 Nav2 and Hav5 Nav2 during epizootic infection among sea gulls in the Astrakhan district in the summer of 1976]. / Izoliatsiia virusa grippa s antigennoi formuloi Hav4 Nav2 i Hav5 Nav2 v period epizootii sredi chaikovykh ptits letom 1976 g. v Astrakhanskoi oblasti.

Virological examinations of nesting colonies of Laridae birds in the avandelta of the Volga, Astrakhan region, during an epizootic in July, 1976, yielded 5 strains of influenza virus: 3 from Sterna albifrons, 1 from S. hirundo and 1 from Larus genei, identical with A/Sterna hirundo/S. Africa/61 (Hav5 Nav2) virus. At the same period two strains were isolated from Larus genei showing a previously unknown composition of the surface antigens: Hav4 Nav2. All the strains were isolated only from cloacal washings.