Accident Recovery Workers Research Articles

Amoxicillin secretion by gastric mucosa in Chernobyl nuclear power plant accident recovery workers with atrophic and nonatrophic gastritis undergoing eradication therapy

Relevance. Today gastric cancer is still one of the oncologic diseases most often leading to death. H. pylori eradication reduces risk of gastric cancer, but its efficacy depends on gastric mucosa state. Atrophy of gastric mucosa is more common in Chernobyl nuclear power plant (CNPP) accident recovery workers than in patients who have not been involved in CNPP accident recovery works. It seems especially important to investigate the features of antibiotics transport to H. pylori colonization area in this contingent.Intention – to determine the features of amoxicillin secretion by gastric mucosa in CNPP accident recovery workers with atrophic and nonatrophic gastritis undergoing H. pylori eradication.Methodology. 65 CNPP accident recovery workers were divided into groups depending on state of gastric mucosa according to endoscopic and histological examination, immunosorbent assay of pepsinogens I and II and gastrin-17 basal serum levels. On the first day of eradication therapy, gastric secretion samples were obtained via nasogastric probe 30, 60, 120, 180 and 240 minutes after oral amoxicillin administration. Drug concentrations in gastric secretion were assessed via liquid chromatography-mass spectrometry.Results and discussion. Amoxicillin concentrations in gastric secretion samples were lower (р < 0.01) in patients with atrophic antral gastritis than in patients with normal gastric mucosa and atrophic fundal gastritis. Patients with fundal atrophy were characterized by lower amoxicillin concentrations 30 and 60 (p = 0.02) minutes after drug intake than in patients with normal gastric mucosa, and higher concentration in the 120th (p < 0.01) and 180th (p = 0.02) minute than in patients with antral atrophy. Amoxicillin concentrations in patients with antral atrophy were lower (p < 0.01) than in non-atrophy group in the 30th, 60th and 120th minute. In the 240th minute, amoxicillin concentrations in patients with fundal atrophy exceeded concentrations in both other groups (p < 0.01). Amoxicillin concentration peak was registered in patients with fundal and antral atrophy in the 180th minute, in patients without atrophy – from the 30th to 120th minute.Conclusion. Atrophy of gastric mucosa is characterized by decreased transport of orally administered amoxicillin from bloodstream to gastric lumen. Depending on gastric mucosa state, amoxicillin concentrations in gastric secretion should be evaluated at different time points after drug administration: in patients with atrophic gastritis – in the 180th minute, in patients without atrophy – in the 120th minute. While predicting the efficacy and choosing H. pylori eradication regimen, morphological and functional state of gastric mucosa should be taken into account.

Anti-parietal cell antibodies seroconversion in patients with autoimmune atrophic gastritis: a prospective study

The purpose of the study was to evaluate the atrophic changes of body and antrum gastric mucosa, the occurrence of Helicobacter pylori infection and the possibility of seroconversion in patients with autoimmune gastritis throughout 10 years.
 Material and methods. 203 Chernobyl nuclear power plant accident recovery workers were included in the prospective study. Blood levels of anti-parietal cell antibodies, basal gastrin-17, pepsinogens I and II were evaluated in all the patients to diagnose autoimmune gastritis and to assess gastric mucosa non-invasively.
 Results. Anti-parietal cell antibodies were found in 34.5% of the patients. Eradication rates were low (32.850.0%) in the patients with atrophy of gastric mucosa in the first 3 years of observation. Statistically significant decrease in pepsinogen I and gastrin-17 serum levels was observed in the patients with H. pylori-associated autoimmune gastritis throughout first 46 years. In the next 710 years pepsinogen I and gastrin-17 serum levels were increasing possibly due to positive effect of H. pylori eradication therapy. Successful eradication leads to disappearance of anti-parietal cell antibodies in 33.4% of the patients by the 10th year of the observation.
 Conclusion. The obtained results show that H. pylori eradication therapy is effective in reducing atrophic changes of gastric mucosa in the patients with autoimmune gastritis. Against the background of successful treatment the levels of pepsinogen I and gastrin-17, the markers of body and antrum gastric mucosa atrophy, were increasing. In the patients with autoimmune gastritis but without H. pylori infection the following trend was not noticed.

Atrophic gastritis in Chernobyl nuclear power plant accident recovery workers in remote period

Relevance. Digestive diseases are among the most common disorders affecting Chernobyl nuclear power plant (CNPP) accident recovery workers. Intention - to assess the occurrence of atrophic changes in fundal and antral gastric mucosa, occurrence of H. pylori infection, and autoimmune gastritis in CNPP accident recovery workers in remote period. And to define connection between the obtained results and external radiation dose, duration of participation in recovery works, and the date of participation. Methodology. 197 CNPP accident recovery workers were examined 30 years or more after the accident. 106 employees of the EMERCOM of Russia were included in comparison group. Levels of basal gastrin-17, pepsinogen I, pepsinogen II, anti- parietal cell antibodies, anti-H. pylori antibodies were evaluated in all the patients. Information on external radiation dose, duration of participation in recovery works, and date of participation was provided by North-West regional center of National Radiation Epidemiological Registry. Results and discussion. Atrophic changes of gastric body mucosa were found in 12.7 % of CNPP accident recovery workers vs 8.1 % of patients (p < 0.01) in comparison group. Gastric antrum atrophy was also statistically significantly (p < 0.01) more common in CNPP accident recovery workers (24.4 %) than in comparison group (10.8 %), as well as atrophic pangastritis (2.0 % vs 0.9 %, p < 0.01). There was no statistically significant difference (p > 0.05) in anti-parietal cell antibodies between 2 groups: the test was positive in 39.1 % of CNPP accident recovery workers and in 37.7 % of comparison group patients. Meanwhile, increased levels of anti- H. pylori antibodies were observed in 70.1 % of CNPP accident recovery workers vs 28.2 % of comparison group patients (p < 0.05). Conclusion. Atrophic changes in gastric body and fundal mucosa and H. pylori infection were more common in CNPP accident recovery workers than in patients of comparison group. There were no correlations between these changes and external radiation dose, duration of the participation in recovery works and the date of participation in CNPP recovery activities.

The state of the intestinal microbiota and the level of cholesterol in the liquidators of the consequences of the accident at the Chernobyl nuclear power plant in the distant period

Relevance. Increasing prevalence of concomitant pathology among the Chernobyl accident recovery workers is associated with long-term adverse health effects. Due to a significant role of dyslipidemia, microbiological disorders of the gastrointestinal tract should be assessed along with individual indicators of cholesterol metabolism. Intention. To study the features of the gut microbiome composition in the Chernobyl accident recovery workers. Methods. Lipid metabolism was assessed based on the total cholesterol in the blood serum. Parietal intestinal microbiota was studied via gas chromatography-mass spectrometry of microbial markers. The study group consisted of 94 Chernobyl accident recovery (1986-1990) workers aged 53-80 years with various somatic pathology. Results and discussions . It was found that patients with elevated serum cholesterol had numerous microbial markers of Lactobacillus and Rhodococcus in the mucosal layer of the intestine, as well as aerobic bacteria which are the sign of dysbiosis. The most pronounced differences in the structure of the interrelations of “useful” and other intestinal microorganisms are associated with Lactobacillus. Representatives of “useful” gut microbiome, in addition to Lactobacillus, obviously correlate with each other. Conclusion. According to the study results, there is a relationship between gut microbiome composition and lipid metabolism. Lipid metabolism disorders are associated with qualitative and quantitative changes in the composition of gut microbiome in Chernobyl recovery workers. No statistically significant correlations were observed between parameters under study and radiation exposure or the year of participation in recovery work.

THE ABILITY OF CYTOGENETIC ANALYSIS TO ESTIMATE RADIATION DOSES RETROSPECTIVELY IN CHERNOBYL ACCIDENT RECOVERY WORKER

Relevance. There is a need to evaluate doses retrospectively in Chernobyl nuclear power plant accident recovery workers without established external doses.Intention: To assess the ability of cytogenetic analysis to estimate external radiation doses retrospectively in Chernobyl nuclear power plant accident recovery workers exposed to low-dose radiation in the remote period.Methodology. Cytogenetic biological indication and biological dosimetry were performed in Chernobyl nuclear power plant accident recovery workers 27–30 years after their participation in recovery works. Stable and unstable chromosome aberrations were assessed in peripheral blood lymphocytes.Results and Discussion. The analysis of unstable chromosome aberrations showed that 45.1 % of Chernobyl nuclear power plant accident recovery workers had radiation markers more frequently than in the comparison group. Biological doses were retrospectively evaluated in 18 % of Chernobyl nuclear power plant accident recovery workers and ranged within 14–48 cGy. Specific anamnestic factors should be assessed while evaluating doses retrospectively.Conclusion. Analysis of stable chromosome aberrations allows retrospective dosimetry after low-dose exp sure if external dose is unavailable. Based on this, adverse health effects of low-dose exposure can be assessed and reimbursed in Chernobyl nuclear power plant accident recovery workers.

Integral Assessment of Plasma Hemostasis State in Chernobyl Accident Recovery Workers with Circulatory Diseases

Integral Assessment of Plasma Hemostasis State in Chernobyl Accident Recovery Workers with Circulatory Diseases

Investigations on Health Conditions of Chernobyl Nuclear Power Plant Accident Recovery Workers from Latvia in Late Period after Disaster

Abstract The paper summarises the main findings on Chernobyl Nuclear Power Plant (CNPP) accident recovery workers from Latvia and their health disturbances, which have been studied by the authors during the last two decades. Approximately 6000 persons from Latvia participated in CNPP clean-up works in 1986–1991. During their work period in Chernobyl they were exposed to external as well as to internal irradiation, but since their return to Latvia they were living in a relatively uncontaminated area. Regular careful medical examinations and clinical studies of CNPP clean-up workers have been conducted during the 25 years after disaster, gathering knowledge on radiation late effects. The aim of the present review is to summarise the most important information about Latvian CNPP clean-up worker health revealed by thorough follow-up and research conducted in the period of 25 years after the accident. This paper reviews data of the Latvian State Register of Persons Exposed to Radiation due to CNPP Accident and gives insight in main health effects found by the researchers from the Centre of Occupational and Radiological Medicine (Pauls Stradiņš Clinical University Hospital) and Rīga Stradiņš University in a number of epidemiological, clinical, biochemical, immunological, and physiological studies. Latvian research data on health condition of CNPP clean-up workers in the late period after disaster indicate that ionising radiation might cause premature ageing and severe polymorbidity in humans.

Capabilities for Clinical Management of Radiation Injuries of the Nikiforov Russian Center of Emergency and Radiation Medicine (EMERCOM of Russia)

This article presents an overview of the capabilities for clinical management of radiation injuries available at the Nikiforov Russian Center of Emergency and Radiation Medicine (NRCERM) of the Ministry of the Russian Federation for Civil Defense, Emergencies and Elimination of Consequences of Natural Disasters (EMERCOM). NRCERM is a federal state budgetary institution and the Russian Federation's head organization for providing medical assistance for persons overexposed to ionizing radiation, responders to radiation emergencies and people evacuated from radiation contaminated areas. As the WHO Collaborating Center for Treatment and Rehabilitation of Accident Recovery Workers of Nuclear and Other Disasters and a member of the WHO Radiation Emergency Medical Preparedness and Assistance Network (REMPAN), NRCERM is prepared to provide assistance and technical support in case of a radiation accident. For this purpose, NRCERM hospitals are equipped with technologically advanced facilities and possess well-trained specialist staff.

Telomere length in Chernobyl accident recovery workers in the late period after the disaster.

The outcome of the Chernobyl nuclear power plant (CNPP) accident was that a huge number of people were exposed to ionizing radiation. Previous studies of CNPP clean-up workers from Latvia revealed a high occurrence of age-associated degenerative diseases and cancer in young adults, as well as a high mortality as a result of cardiovascular disorders at age 45–54 years. DNA tandem repeats that cap chromosome ends, known as telomeres, are sensitive to oxidative damage and exposure to ionizing radiation. Telomeres are important in aging processes and carcinogenesis. The aim of this study was to investigate the long-term effect of protracted ionizing radiation exposure on telomere length in CNPP clean-up workers. Relative telomere length (RTL) was measured in peripheral blood leukocytes of 595 CNPP clean-up workers and 236 gender- and age-matched controls using real-time quantitative polymerase chain reaction (q-PCR). Close attention was paid to participation year and tasks performed during the worker's stay in Chernobyl, health status, and RTL differences between subgroups. Telomere shortening was not found in CNPP clean-up workers; on the contrary, their RTL was slightly greater than in controls (P = 0.001). Longer telomeres were found in people who worked during 1986, in those undertaking ‘dirty’ tasks (digging and deactivation), and in people with cancer. Shorter telomeres appeared frequently in those with cataract, osteoporosis, atherosclerosis, or coronary heart disease. We conclude that the longer telomeres revealed in people more heavily exposed to ionizing radiation probably indicate activation of telomerase as a chromosome healing mechanism following damage, and reflect defects in telomerase regulation that could potentiate carcinogenesis.

Chernobyl’s Legacy: Black Prophecies’ Bubble

On April 26, 1986, the Chernobyl nuclear accident occurred. Thirty people died within several weeks, while the accident's scale was unprecedented—and probably about the largest theoretically possible. Many predictions were then made, including rumors concerning up to million cancer deaths. Most of those predictions were a priori unobservable and therefore unscientific. The reality turned out to be absolutely different. According to solid scientific data gained over one quarter of a century, 15 cancer deaths at most may be directly attributed to fallout radiation. In particularly, no conclusion could be drawn concerning the presence or absence of a radiation-related excess of cancer—including leukemia—among Chernobyl accident recovery workers, who received rather high (and well-documented) radiation doses. The number of radiation-related mutations (congenital malformations) is zero. Two popular myths challenge the above scientific evidence: (a) the raw medical data is filtered by local governments; (b) the international agencies that summarize the data (like IAEA, UNSCEAR and WHO) are pro-nuclear biased. Both arguments are, speaking politically-correct, alternatively convincing. On the other hand it should be stressed that the myths and misperceptions about the threat of radiation themselves caused enormous human suffering. In addition to the socio-economic problems associated with relocation (mostly unjustified), people have suffered a paralyzing fatalism, which has contributed to a culture of chronic dependency. Mental health problems, leading to and coupled with smoking and alcohol abuse, proved to be a very much greater problem than radiation. Similar problems should be avoided in future accidents by means of proper transparency.

Использование магниторезонансной спектроскопии при системном анализе радиочувствительности/радиорезистентности животных и человека

The responses of deoxyribonucleotide (dNTP), DNA and protein synthesis systems in blood-forming organs of animals (dogs, mice) as well as changes in Fe(3+)-transferrin (Fe(3+)-TF) and Cu(2+)-ceruloplasmin (Cu(2+)-CP) pools in blood to gamma-irradiation and the administration of radioprotectors have been studied. It has been shown that changes in Fe(3+)-TF and Cu(2+)-CP pools in blood are indices of changes in the body radioresistance and are reliably controlled by the EPR technique. An increase in the Fe(3+)-TF pool promotes the activated synthesis of dNTP, DNA and Fe(3+)-containing proteins which are essential for the repair efficiency during the early post-irradiation time as well as for the development of compensatory and restorative reactions of cellular systems; i.e., they are responsible for the body resistance to DNA-damaging factors. It is important that the intensity of responses depends on the initial state of the organism. It has been shown, that changes in Fe(3+)-transferrin and Cu(2+)-ceruloplasmin pools, which are trust-worthy controlled by the EPR technique in whole blood, blood plasma, and serum, as well as the changes in the extracellular DNA content in blood plasma are the markers of the changes in the organism radioresistance. This has been proved during the medical examination of the Chernobyl accident recovery workers and civil population, including children, exposed to low-intensity radiation.

Investigation of the impact of radiation dose on hormones, biologically active metabolites and immunoglobulins in Chernobyl accident recovery workers.

One hundred twenty-five Chernobyl accident recovery workers (liquidators) who were exposed to low-dose radiation were studied over a period of 4-6 years for changes in levels of hormones, arachidonic acid metabolites and cyclic nucleotides. Some significant changes were observed, especially in the levels of metabolites that are regulators of cell functions. In comparison to controls, there were increased levels of thyroxin, cortisol, thromboxane B2, and immunoglobulins G, A and M, and reduced levels of growth hormone, cyclic nucleotides and 6-keto-prostaglandin F1. The degree or presence of these metabolite imbalances did not correlate with the level of the radiation dose received. The only change found that did relate to the radiation dose received was a statistically significant increase in levels of biomarkers for oxidative stress, seen in workers who received higher doses.

Risk of hematological malignancies among Chernobyl liquidators.

A case-control study of hematological malignancies was conducted among Chernobyl liquidators (accident recovery workers) from Belarus, Russia and Baltic countries to assess the effect of low- to medium-dose protracted radiation exposures on the relative risk of these diseases. The study was nested within cohorts of liquidators who had worked around the Chernobyl plant in 1986-1987. A total of 117 cases [69 leukemia, 34 non-Hodgkin lymphoma (NHL) and 14 other malignancies of lymphoid and hematopoietic tissue] and 481 matched controls were included in the study. Individual dose to the bone marrow and uncertainties were estimated for each subject. The main analyses were restricted to 70 cases (40 leukemia, 20 NHL and 10 other) and their 287 matched controls with reliable information on work in the Chernobyl area. Most subjects received very low doses (median 13 mGy). For all diagnoses combined, a significantly elevated OR was seen at doses of 200 mGy and above. The excess relative risk (ERR) per 100 mGy was 0.60 [90% confidence interval (CI) -0.02, 2.35]. The corresponding estimate for leukemia excluding chronic lymphoid leukemia (CLL) was 0.50 (90% CI -0.38, 5.7). It is slightly higher than but statistically compatible with those estimated from A-bomb survivors and recent low-dose-rate studies. Although sensitivity analyses showed generally similar results, we cannot rule out the possibility that biases and uncertainties could have led to over- or underestimation of the risk in this study.

Anticlastogenic effects of Ginkgo biloba extract (EGb 761) and some of its constituents in irradiated rats

In a previous study we reported that radiation-induced clastogenic factors (CF) are found in the plasma of Chernobyl accident recovery workers and that their chromosome damaging effects are inhibited by antioxidant treatment with a Ginkgo biloba extract (EGb761). In the present study, we induced CF in rats with a radiation dose of 4.5 Gy. The protective effects of the complete extract were compared to those obtained with the extract devoid of its terpene fraction (CP205), with isolated ginkgolides A+B and bilobalide at the concentrations present in EGb761. The pretreatment samples were taken at day 22 postirradiation, the posttreatment samples the day following arrest of the 3-week treatment. The adjusted clastogenic score (ACS) were reduced from 11.71±3.55 to 2.00±2.83 after treatment with 100 mg/kg and from 13.43±2.23 to 4.29±2.14 with 50 mg/kg of the complete extract ( p<0.0001). Similar protective effects were observed with CP205, ginkgolides and bilobalide ( p<0.001), while the reduction of ACS in placebo-treated rats was not statistically significant (12.80±1.79 and 9.20±2.68). However, if the efficacy of the treatment was compared to placebo, only the complete extract was significantly protective. While all components exerted anticlastogenic effects at the concentrations present in the complete extract, the comparison of the different groups by analysis of variance did not reveal significant differences. This may be due to to the small number of animals available in each treatment group. The complete extract reduced the ACS by 83% at the dose of 100 mg/kg, while the lower dose of 50 mg/kg and the three components reached only 66%–68% reduction. The better protection provided by the complete extract is due to synergistic rather than to additive effects.

Clastogenic Factors in the Plasma of Chernobyl Accident Recovery Workers: Anticlastogenic Effect of Ginkgo biloba Extract

Clastogenic factors are found in the plasma of persons irradiated accidentally or therapeutically. They persisted in the plasma of A-bomb survivors over 30 years. Clastogenic factors were found in 33 of 47 Chernobyl accident recovery workers (often referred to as liquidators) in a previous study (I. Emerit et al., J. Cancer Res. Clin. Oncol. 120, 558-561, 1994). In the present study, we show that there is a positive correlation between clastogenic activity and dose and that these biomarkers of oxidative stress can be influenced successfully by appropriate antioxidant treatment. With the authorization of the Armenian Ministry of Health, 30 workers were treated with antioxidants from Ginkgo biloba leaves. The extract EGb 761 containing flavonoids and terpenoids was given at a daily dose of 3 x 40 mg (Tanakan, IPSEN, France) during 2 months. The clastogenic activity of the plasma was reduced to control levels on the first day after the end of the treatment. A 1-year follow-up showed that the benefit of the treatment persisted for at least 7 months. One-third of the workers again had clastogenic factors after 1 year, demonstrating that the process which produced clastogenic factors continued. However, the observation that antioxidants do not have to be given continuously is encouraging for intervention trials on a large-scale basis. These appear justified, since clastogenic factors are thought to be risk factors for the development of late effects of irradiation.