A reconsideration of the external dose assessment for the Techa river population

A new methodology is employed to infer the time course of the external dose rate that affected the Techa riverside population. This was accomplished using information on the radionuclide composition of released radioactive waste and from earlier and current data on the degree of the river floodplain contamination with (137)Cs. The new approach is proposed for use in the dose reconstruction. Compared to current assumptions it indicates a considerably higher dose contribution due to short-lived fission products from the predominant peak of contamination in 1951. Relative to the present Techa river dosimetry system (TRDS-2000) this information may increase the external dose estimates several fold and correspondingly reduce the solid cancer risk estimate.     

Dose assessment for the Metlino and Muslyumovo populations who lived along the Techa river from 1949 to 1954

In the period from 1949 to 1956, liquid radioactive waste was routinely and accidentally discharged by the Mayak Production Association, Southern Urals, Russia, into the Techa river. Based on a novel approach, the contamination of the Techa river water, the bottom sediments and the adjacent flood plains was modelled, and internal and external doses were estimated for two villages located downstream of the site of liquid radioactive waste release. Altogether, 11 radionuclides that occurred in the liquid radioactive waste were included in the calculations. The results suggest significantly higher doses than previously assumed, with the major contribution in the year 1951. Radionuclides with half-lives of less than 1 year, such as ⁸⁹Sr, ¹³¹I, ⁹⁵Zr+⁹⁵Nb, ¹⁰³Ru+^103mRh, ¹⁴⁰Ba+¹⁴⁰La, and ¹⁴⁴Ce+¹⁴⁴Pr, represent the major sources and, in contrast, long-lived radionuclides, such as ⁹⁰Sr and ¹³⁷Cs that have so far been assumed to be most important, did not dominate the doses. For adults from the village Metlino, located 7 km downstream of the site of liquid radioactive waste discharge, the committed effective doses due to intake of radionuclides were calculated to be about 2.3 Sv, while the external doses were between about 1.2 Sv and 6.9 Sv. On the other hand, for adults from Muslyumovo, located 75 km downstream, the commited effective doses due to intake of radionuclides were calculated to be about 0.5 Sv, while the external doses were between 0.5 Sv and 2.0 Sv. The values for the skin doses to the Metlino and Muslyumovo populations were about 7.1 Sv and 1.3 Sv, respectively. It is concluded that the current dose estimates for the residents of the Techa river need, therefore, reevaluation.     

Metabolic therapy and pulmonary disfunction in patients with obstetric sepsis

The role of reamberin, a succinate-containing infusion preparation in correlation of pulmonary metabolic and respiratory disturbances in patients with obstetric puerperal sepsis was estimated. The prospective randomized study enrolled 43 patients with puerperal obstetric sepsis complicated by polyorganic deficiency (SOFA 8-10). Nineteen patients of the 1st group and 24 patients of the 2nd group were additionally treated with reamberin in a dose of 800 ml/day for 8 days. The venous and arterial difference by glucose, lactate, pyruvate, diene conjugates, malondialdehyde and ceruloplasmin was investigated. The blood gases were determined with the Ciba Corning 45 apparatus. Lower metabolic activity of the lungs with prevalence of the glucose anaerobic metabolism and lower activity of the intrapulmonary antioxidant protection were observed in the patients with obstetric sepsis. The use of reamberin in the complex therapy of obstetric sepsis promoted maintenance of the initial balance and anaeroibic and aerobic pulmonary metabolism, thus providing shorter terms of the decompensation and recovery of the lungs respiratory function.     

Reconstruction of the radionuclide spectrum of liquid radioactive waste released into the Techa river in 1949-1951

The major part of the liquid radioactive waste released by the Mayak Production Association (PA) radiochemical plant into the Techa river occurred in 1949-1951, but there is information on only one single radiochemical analysis of a water sample taken on 24 and 25 September 1951. These data are here used to assess the spectrum of radionuclides that were released between 1949 and 1951. For this purpose, details of the radiochemical methods of radionuclide extraction and radiometric measurements of beta-activity used at Mayak PA in the 1950s have been taken into account. It is concluded that the data from the radiochemical measurements agree with the theoretical composition of fission products in uranium after exposure times in the reactor (120 days) and subsequent hold times (35 days) that were typical for the procedures at that time. The results of the analysis are at variance with assumptions that underlie the current Techa river dosimetry system. They confirm the conclusion that the external doses to the Techa river residents in the critical period up to 1952 were predominantly due to short-lived fission products.     

External radiation exposure of residents living close to the Mayak facility: main sources,dose estimates,and comparison with earlier assessments

Radiation and Environmental Biophysics -     

Structural comparison of fibroblast growth factor-specific heparan sulfates derived from a growing or differentiating neuroepithelial cell line

Heparan sulfate (HS) glycosaminoglycans are essential modulators of fibroblast growth factor (FGF) activity both in vivo and in vitro, and appear to act by cross-linking particular forms of FGF to appropriate FGF receptors. We have recently isolated and characterized two separate HS pools derived from immortalized embryonic day 10 mouse neuroepithelial 2.3D cells: one from cells in log growth phase, which greatly potentiates the activity of FGF-2, and the other from cells undergoing contact-inhibition and differentiation, which preferentially activates FGF-1. These two pools of HS have very similar functional activities to those species isolated from primary neuroepithelial cells at corresponding stages of active proliferation or differentiation. We present here a structural comparison between these cell line HS species to establish the nature of the changes that occur in the biosynthesis of HS. A combination of chemical and enzymatic cleavage, low pressure chromatography and strong anion-exchange HPLC were used to generate full chain models of each species. Overall, the HS pools synthesized in the dividing cell line pools possessed less complex sulfation than those derived from more differentiated, growth arrested cells.      

Evaluation of external exposures of the population of Ozyorsk,Russia, with luminescence measurements of bricks

Recently discovered historical documents indicate that large releases of noble gases (mainly ⁴¹Ar and radioactive isotopes of Kr and Xe) from the Mayak Production Association (MPA) over the period from 1948 to 1956 may have caused considerable external exposures of both, inhabitants of Ozyorsk and former inhabitants of villages at the upper Techa River. To quantify this exposure, seven brick samples from three buildings in Ozyorsk, located 8–10 km north-northwest from the radioactive gas release points, were taken. The absorbed dose in brick was measured in a depth interval of 3–13 mm below the exposed surface of the bricks by means of the thermoluminescence (TL) and the optically stimulated luminescence (OSL) method. Generally, luminescence properties using TL were more favorable for precise dose determination than using OSL, but within their uncertainties the results from both methods agree well with each other. The absorbed dose due to natural radiation was assessed and subtracted under the assumption of the bricks to be completely dry. The weighted average of the anthropogenic dose for all samples measured by TL and OSL is 10 ± 9 and 1 ± 9 mGy, respectively. An upper limit for a possible anthropogenic dose in brick that would not be detected due to the measurement uncertainties is estimated at 24 mGy. This corresponds to an effective dose of about 21 mSv. A similar range of values is obtained in recently published dispersion calculations that were based on reconstructed MPA releases. It is concluded that the release of radioactive noble gases from the radiochemical and reactor plants at Mayak PA did not lead to a significant external exposure of the population of Ozyorsk. In addition, the study demonstrates the detection limit for anthropogenic doses in ca. 60-year-old bricks to be about 24 mGy, if luminescence methods are used.     

Experience in the application of Java Technologies in telemedicine

Java language has been demonstrated to be an effective tool in supporting medical image viewing in Russia. This evaluation was completed by obtaining a maximum of 20 images, depending on the client's computer workstation from one patient using a commercially available computer tomography (CT) scanner. The images were compared against standard CT images that were viewed at the site of capture. There was no appreciable difference. The client side is a lightweight component that provides an intuitive interface for end users. Each image is loaded in its own thread and the user can begin work after the first image has been loaded. This feature is especially useful on slow connection speed, 9.6 Kbps for example. The server side, which is implemented by the Java Servlet Engine works more effective than common gateway interface (CGI) programs do. Advantages of the Java Technology place this program on the next level of application development. This paper presents a unique application of Java in telemedicine.     

Effects of age,replicative lifespan and growth rate of human nucleus pulposus cells on selecting age range for cell-based biological therapies for degenerative disc diseases

Autologous disc cell implantation, growth factors and gene therapy appear to be promising therapies for disc regeneration. Unfortunately, the replicative lifespan and growth kinetics of human nucleus pulposus (NP) cells related to host age are unclear. We investigated the potential relations among age, replicative lifespan and growth rate of NP cells, and determined the age range that is suitable for cell-based biological therapies for degenerative disc diseases. We used NP tissues classified by decade into five age groups: 30s, 40s, 50s, 60s and 70s. The mean cumulative population doubling level (PDL) and population doubling rate (PDR) of NP cells were assessed by decade. We also investigated correlations between cumulative PDL and age, and between PDR and age. The mean cumulative PDL and PDR decreased significantly in patients in their 60s. The mean cumulative PDL and PDR in the younger groups (30s, 40s and 50s) were significantly higher than those in the older groups (60s and 70s). There also were significant negative correlations between cumulative PDL and age, and between PDR and age. We found that the replicative lifespan and growth rate of human NP cells decreased with age. The replicative potential of NP cells decreased significantly in patients 60 years old and older. Young individuals less than 60 years old may be suitable candidates for NP cell-based biological therapies for treating degenerative disc diseases.