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PubMed2005

Microfibril angle in wood of Scots pine trees (Pinus sylvestris) after irradiation from the Chernobyl nuclear reactor accident.

The secondary cell wall structure of tracheids of Scots pine (Pinus sylvestris L.), especially the angle of microfibrils in the S(2) layer, was examined in wood deposited prior to and after the Chernobyl accident in 1986. Microscopic analysis was carried out on wood samples collected in October 1997 from breast height of three pine trees 16, 30 and 42 years old. The polluted site was located in a distance of 5 km south from the Chernobyl nuclear power plant where radioactive contamination in 1997 was 3.7 x 10(5) kBq m(-2). Anatomical analysis showed that the structure of the secondary cell wall in tracheids formed after the Chernobyl accident was changed. Changes occurred both in S(2) and S(3) layers. The angle of microfibrils in S(2) layer in wood deposited after the Chernobyl accident was different in comparison to this measured in wood formed prior to the disaster. The intensity of the changes, i.e. alteration of the microfibrils angle in S(2) layer and unusual pattern of the S(3) layer, depended on the age of the tree and was most intensive in a young tree.

Cell Wall↗

PubMed2004

National cancer registry to assess trends after the Chernobyl accident.

The National Cancer Registry has been operational in the Republic of Belarus since 1973: information on all new cases of malignant tumours is registered. The data are kept in a computer database and used for assessing the oncological status of the population, and for epidemiological studies. We compared findings before the Chernobyl accident of April 26, 1986 (Chernobyl) and findings between 1990 and 2000. The overall comparison on the changes in the incidence of cancer morbidity in Belarus is presented. The increase is statistically significant for all regions, but significantly greater in the most chronically radiation-contaminated region: the Gomel oblast. The paper presents a comparative analysis of the incidence of cancer morbidity in the population of two regions of Belarus, selected for the greatest difference in their radioactive contamination following Chernobyl. The highest contamination occurred in the Gomel region and is mainly due to high levels of radiocaesium (137Cs) in the soil and in the alimentary chain, especially in rural areas. A relatively low radioactive fallout was noticed in the Vitebsk region, considered here as the "control" area. We compare the situation before and after Chernobyl in the two regions. The overall cancer morbidity rate in all organs including colon, urinary bladder and thyroid, was significantly higher in the Gomel region than in Vitebsk. In populations living in two areas with high 137Cs contamination (oblast of Gomel and Mogilev), the peak incidence rates of breast cancer were already reached between the ages of 45-49 years, 15 years earlier than in the Vitebsk region. Belarussian "liquidators" who were mobilised to clean up the most contaminated territory and build the sarcophagus around the destroyed atomic plant, received the highest radiation doses. They had a significant excess of incidence of cancers of colon, urinary bladder, and thyroid gland, when compared with a corresponding adult population of the Vitebsk region. The Relative Risk (RR) of lung cancer among "liquidators" in 1997-2000 significantly exceeded 1, while in the control population it remained stable.

Breast Neoplasms↗

PubMedDate not supplied

[Time-effect relationship for unstable chromosome exchange levels in Chernobyl clean-up workers].

The post-irradiation changes of dicentric and centric ring levels were studied in Chernobyl liquidators using the data of 507 individual chromosomal surveys of persons sampled at different time after their activities at Chernobyl NPP accident zone. The time-effect relationship within 0-10.5 years after exposure was displayed as exponential decline of the mean chromosome exchange frequency with average decay half-time 2.2 y. During 10.5-13 years after exposure the increasing and stabilization of chromosome exchange yield on the level 2-3-times higher than control was observed. In the first few months after irradiation the dicentric and centric ring frequency in liquidators had the clear reverse correlation with the duration of person's duties at the Chernobyl zone. The parameters of unstable chromosome exchange elimination were independent on the initially induced aberration yield, that resulted in earlier reaching the subcontrol level in persons who had more protracted duration of duties at the Chernobyl accident zone.

Adult↗

PubMedDate not supplied

[Role of non-radiation factors in forming cytogenetic effects in evacuees from a 30-km zone of the Chernobyl Nuclear Power Plant].

The time-effect relationship for chromatid type aberrations, chromosome type fragments, hyperploidy and polyploidy levels in peripheral blood lymphocytes were investigated in inhabitants of t. Pripiat' and nearby villages, who were departured from the Chernobyl NPP 30-km exclusive zone during first days after the Chernobyl catastrophe. The time-course changes of the mentioned cytogenetic indices in evacuees were displayed as a gradual decline of chromosomal rearrangements and genome abnormality frequencies from the statistically elevated level in the first 1-2 years after the accident to the subcontrol meanings at the end of the 14-years observation period. In early terms after exposure the frequency of chromatid exchanges in adult men and the polyploidy level in women aged 23-35 years were sufficiently increased comparing with other evacuee subgroups. Some peculiarities of the fragment aberration frequency dynamics were shown for persons with different terms of the departure from the Chernobyl zone. The role of the combination of mutagenic factors acted in the accidental situation at Chernobyl for inducing the elevated level of cytogenetic damage in evacuees is discussed.

Adolescent↗

PubMedDate not supplied

[The effect of Chernobyl accident on the development of non malignant diseases].

The early medical complications of Chernobyl accident include post radiation disease, which were diagnosed in 134 subjects affected by ionizing radiation. 28 persons died during the first 100 days after the event. The increase occurrence of coronary heart disease, endocrine, haematological, dermatological and other diseases were observed after disaster in the contaminated territories. We also discussed the impact of ionizing radiation from Chernobyl accident on pregnancy and congenital defects occurrence. Changes following the Chernobyl accident, as the inhabitants migration from contaminated regions, political and economic conversions, led to depression, anxiety, and even to "epidemic" of mental diseases. Increased suicide rate, car accidents, alcohol and drug abuse have been observed in this population. Nowadays vegetative neurosis is more often diagnosed in Ukrainian children. Epidemiological studies were conducted on the ionising radiation effect on the health and on the dose of received radiation after Chernobyl accident face numerous problems as the absence of reliable data regarding diseases in the contaminated territories.

Abnormalities, Radiation-Induced↗

PubMed2006

Patterns of hematological malignancies in Chernobyl clean-up workers (1996-2005).

AIM: The question as to whether the incidence of leukemias and malignant lymphomas among the Chernobyl clean-up workers increased in 20 years after the catastrophe is still a point of much controversy. Precise diagnosis of the main forms of hematopoietic malignancies according to FAB classification and new WHO classification and comparison of these data with that in the general population will be helpful in estimating the relative contribution of the radiation factor to the overall incidence of such pathologies. PATIENTS AND METHODS: The data on 218 consecutive cases of malignant diseases of hematopoietic and lymphoid tissues in Chernobyl clean-up workers diagnosed in 1996-2005 are given in comparison with the data of 2697 consecutive patients of general population of the same age group. The morphology and cytochemistry of bone marrow and peripheral blood cells were studied. Immunocytochemical techniques (APAAP, LSAB-AP) and the broad panel of monoclonal antibodies to lineage specific and differentiation antigens of leukocytes were employed for immunophenotyping leukemic cells. RESULTS: Various types of oncohematological diseases developing 10-20 years after Chernobyl accident were registered in a group of clean-up workers under study including myelodysplastic syndromes (MDS), acute leukemias (ALL and AML), chronic myelogenous leukemia (CML) and other chronic myeloproliferative diseases, chronic lymphocytic leukemia (B-CLL) and other chronic lymphoproliferative diseases of B and T cell origin. MDS percentage among patients of clean-up workers group tended to exceed MDS percentage in the group of patients representing the general population examined at the same period (4.58 vs. 3.70%). Among 34 AML cases, leukemia was preceded by MDS in seven patients. The relative contribution of CML to the total number of clean-up workers with leukemia was higher than the corresponding percentage value in general population examined at the same period (9.17 vs. 6.59%). B-CLL was a predominant form of hematopoietic malignancies in clean-up workers under study (25.68%). Nevertheless, B-CLL percentage in patients of clean-up workers group did not differ significantly from that in the patients of general population. The multiple myeloma percentage (7.79%) in the group of patients belonging to clean-up workers in our study turned out to be twice as much as in the patients of general population (4.0%). CONCLUSION: The verified diagnosis of tumors of hematopoietic and lymphoid tissue according to modern classification (EGIL, WHO) could be the prerequisite for further molecular genetic and analytical epidemiology study of leukemias that may be related to Chernobyl NPP accident consequences.

Antigens, CD↗

PubMedDate not supplied

[20 years after Chernobyl accident--is it a lot or not for the estimation its characteristics ?].

The results of long standing researches in the zones, which suffered from Chernobyl accident, on cultured cells, mice, blood lymphocytes of inhabitants of polluted regions (adults and children) are brought in the paper. The conclusion is that residence in polluted territories results in genomic instability, that is manifested in many effects on cytogenetic, cellular and organisms levels. It was shown, that in late descendants of cells after exposition in Chernobyl zone the increase of cell death, the micronuclei level, the frequency of giant cells, the enhancement of radiosensitivity and the absence of the adaptive response was observed. In the culture of embryonic fibroblasts, that was obtained from the exposed mice, the increase of cells with aberrations of chromosome and the frequency of multiaberrant cells was noticed. In mice exposed in Chernobyl zone the decrease of amounts of the endothelial cells in the different parts of the brain, the enhancement of mice radiosensitivity was observed. All effects were discovered in the late descendants of cells and can be the result of genomic instability induced by low level irradiation in polluted by Chernobyl accident regions.

Adaptation, Biological↗

PubMedDate not supplied

[The effect of Chernobyl accident on the development of malignant diseases--situation after 20 years].

The accident that occurred at the Chernobyl Nuclear Power Plant in 1986, released large quantities of radionuclides--among them radioiodine--into the atmosphere, thereby raising public concerns about its influence on thyroid structure and function, especially the development of malignancy. There were even reports about 700 deaths due to thyroid carcinoma in Russian Federation, Ukraine and Belarus, resulting from the accident. In this review we discussed the incidence of thyroid cancer in different parts of the world, especially in heavily contaminated countries, as Ukraine and Belarus, and the possible link between radioisotope activity in the thyroid and the development of malignancy. The study carried out in Minsk showed 40-fold increase of the incidence of thyroid cancer in the years 1986-1994, in comparison to the period 1977-1985. An increase of the incidence of thyroid cancer has generally been observed in many countries after the Chernobyl accident. We focused on the factors that may have an influence on this phenomenon, especially diagnostic tests, health care, social and environmental factors, like iodine level in water and soil. The results of molecular biology studies, e.g. RET translocation in carcinoma type RET/PTC1 in elderly and RET/PTC3 in children, and expression Ax1 and Gas6 in children were reviewed as well. We also mentioned other thyroid diseases, like nodular goitre, cysts, the disturbance of thyroid function and autoimmunity, possibly linked to the radiation after Chernobyl accident. Data obtained from the regions near Chernobyl showed no increased risk of other types of malignancy (leukaemia, Hodgkin's and non Hodgkin's lymphoma) in 1986-1996. In this article the epidemiology of thyroid diseases in Poland was also reviewed.

Adolescent↗

PubMed1999

NTRK1 re-arrangement in papillary thyroid carcinomas of children after the Chernobyl reactor accident.

The prevalence of NTRK1 re-arrangement was determined in papillary thyroid carcinomas (PTCs) of children from Belarus who had been exposed to radioactive iodine after the Chernobyl reactor accident; 81 tumors were included, all of which were devoid of RET re-arrangement as analyzed in a current study on genomic alterations in PTC. Oncogenic fusion of the NTRK1 tyrosine kinase domain with the amino-terminal part of the tropomyosin gene (TPM3/NTRK1, trk) was observed in 5 tumors. A single tumor exhibited a TPR/NTRK1 fusion (TRK-T2). Reciprocal NTRK1/TPM3 transcripts were found in 4 of 5 tumors with TPM3/NTRK1 re-arrangement, indicating an intra-chromosomal balanced reciprocal inversion. No phenotypic differences from other post-Chernobyl childhood PTCs were detected. As compared with the high prevalence of RET re-arrangements reported for thyroid carcinomas of children after the Chernobyl reactor accident, NTRK1 re-arrangements appear rare. Our results confirm that activation of receptor tyrosine kinase genes plays the predominant role in post-Chernobyl childhood thyroid carcinogenesis.

Adolescent↗

PubMed1994

Pediatric thyroid cancer after the Chernobyl disaster. Pathomorphologic study of 84 cases (1991-1992) from the Republic of Belarus.

BACKGROUND: During the initial period after the Chernobyl accident, large amounts of radioactive iodine were released in fallout, resulting in serious exposure to the thyroid gland in the residents of areas around the nuclear power station. Beginning in 1990, a definite increase in the incidence of thyroid cancer was noted in children of the Republic of Belarus. METHODS: Morphologic and clinical features of 84 cases of post-Chernobyl thyroid carcinoma in Belarussian children from 5 to 14 years of age are reported. The latent period for tumor development was 4-6 years, with a mean of 5.8 years. RESULTS: Papillary carcinoma was found in 83 patients and medullary carcinoma in one. Besides typical papillary carcinoma (14%), solid (34%), follicular (33%), mixed (10%), and diffuse sclerosing (9%) variants were observed. The follow-up period ranged from 8 months to 2.5 years. One patient died, local recurrence developed in 2, and cervical lymph node metastases developed in 10. To date, the incidence of local recurrence or metastatic disease after surgery was significantly higher in patients 5-8 years of age and in residents of areas nearest to the Chernobyl station. CONCLUSIONS: Post-Chernobyl pediatric thyroid carcinoma is characterized by a short latency, a higher proportion of tumors arising in young children, and an almost equal sex ratio. Microscopically, these tumors were usually aggressive, often demonstrating intraglandular tumor dissemination (92%), thyroid capsular and adjacent soft tissue invasion (89%), and cervical lymph node metastases (88%). Papillary carcinoma was diagnosed in 99% of cases, with an unusually high frequency of solid growth patterns. Morphologic changes in nonneoplastic thyroid tissue were present in 90% of the glands, and the most specific findings were vascular changes and perifollicular fibrosis.

Accidents↗

PubMed1989

Investigation of the possible effect of the Chernobyl accident on Irish mortality rates.

RADIOACTIVE fallout from the Chernobyl accident reached Ireland in May 1986 and caused serious concern with regard to its possible effects on health. Reports of a large scale American study claim an almost immediate effect of Chernobyl fallout in terms of increased mortality rates. A study of Irish mortality rates reported a substantial increase in numbers of deaths during the three months immediately post-Chernobyl. The present study investigates whether there is a statistically significant basis for the reported increase in mortality in Ireland. No discernible evidence was found for increased mortality rates in Ireland during 1986, following the Chernobyl accident. The initial report of increased mortality rates was based on provisional mortality registration statistics and not on actual day by day data.

Accidents↗

PubMed2001

Post-surgical ablation of thyroid residues with radioiodine in Ukrainian children and adolescents affected by post-Chernobyl differentiated thyroid cancer.

Post-surgical ablation of thyroid residues with 131-iodine (131-I) is usually recommended after near-total thyroidectomy in high-risk patients, including children, with differentiated thyroid cancer (DTC). We report here the results of post-surgical radioiodine thyroid ablation in 249 children and adolescents of Ukraine with post-Chernobyl DTC initially treated with near-total thyroidectomy at the Institute of Endocrinology and Metabolism in Kiev, during a 2-year period. The patients' age at the time of the Chernobyl accident (1986), ranged from <1 to 14 yr in 223 subjects (children) and from 15 to 18 yr in 26 subjects (adolescents). Six weeks after surgery a diagnostic 131-I whole body scan revealed the presence of residual thyroid tissue in all cases. All patients received one or more courses of radioiodine therapy, for a total of 468 courses. One hundred and twenty-nine out of 249 patients (51.8%) were successfully ablated. The total number of treatment courses needed in these patients was 219. Most patients required multiple doses of radioiodine, only 63 required a single dose. One hundred and twenty patients (48.2%) treated with radioiodine were not ablated and are still under treatment program. The clinical features and the amount of thyroid residue were not different in ablated or not-ablated patients. Our results indicate that in this particular population of post-Chernobyl thyroid carcinomas, thyroid ablation is a rather difficult task. Only 51.8% were successfully ablated. Possible explanation for this finding may be the young age of the patients, other particular features of post-Chernobyl thyroid carcinoma or technical aspects, such as less radical surgical procedures.

Adolescent↗

PubMed1987

Early Canadian results on the long-range transport of Chernobyl radioactivity.

The levels of Chernobyl-derived radionuclides were measured in several rain, snow and water filtration plant floc samples collected from various locations in Canada. The data indicate that the Chernobyl release had negligible effect on the radiological quality of Lake Ontario waters. The detection of some activation products in pre-Chernobyl samples, presumably arising from the accidental release of radioactivity during weapon testing at the Nevada site, is also reported. Some data from the ongoing measurements on rain samples are presented to discuss the possible use of Chernobyl radionuclides for delineating tropospheric transport processes. Fractionation factors for the major radionuclides are also reported.

Accidents↗

PubMed1991

The effect on lymphocyte chromosomes of additional radiation burden due to fallout in Salzburg (Austria) from the Chernobyl accident.

An investigation has been carried out to determine whether chromosome aberrations in peripheral blood lymphocytes reflect the elevated environmental dose of low-LET ionising radiation, mainly due to radiocesium from Chernobyl fallout, to the population living in Salzburg city. Sixteen volunteers were sampled 1 year after the Chernobyl accident. Two of these persons were also sampled before the accident, and then in 1988 and 1990. The radioactive environment of Salzburg city and the radiation burden of its inhabitants have been frequently determined before and after the accident. The Cs-137 content of the volunteers was measured by whole-body counting. The additional external plus internal radiation doses in the year 1987 to the tested individuals ranged between 15 and 68% of the former normal environmental burden. The aberration frequencies showed a sharp increase of about a factor 6 from the pre-Chernobyl dose rate (0.9. mGy/year) to the post-Chernobyl dose rate (about 2 mGy/year total) but then decreased again with higher additional dose. In the two persons analysed before and up to 4 years after the accident the aberration yield showed a significant increase from 1984/85 to 1987, a decrease in 1988 and a further decrease in 1990. If these last 2 values are plotted against additional dose they fit the curve of the pooled 1987 values. The dose-effect curves revealed the same tendency as we found in various previous investigations and support the assumption that repair enzymes could be triggered by a certain amount of damage to the DNA.

Adult↗

PubMed1988

Chernobyl retrospective.

On April 28, 1986 heavy radioactive fallout from an unknown source was reported from Sweden. Later, it was discovered that two days earlier, a nuclear power reactor at Chernobyl, in the Soviet Union, had exploded releasing an enormous cloud of effluent containing 40 million Ci of 131I, 3 million Ci of 137Cs, and 50 million Ci of xenon radioisotopes. This far exceeded the 15 Ci of 131I escape in the notorious Three Mile Island accident. Chernobyl reactor IV, of an antiquated design, was a graphite-moderated reactor which suffered a steam explosion when the operating staff attempted an experiment involving preservation of safety functions during a planned shutdown. Following the explosion, a fire started in the graphite core which required ten days to control. Thirty-one persons died, two in the initial explosion and 29 of various combinations of thermal and radiation burns, and gamma irradiation. Existing emergency plans were invoked involving treatment on the scene and evacuation of seriously injured patients to a special hospital in Moscow, as well as to nearby Kiev. Later, 135,000 residents of the immediate neighborhood were surveyed and evacuated after fallout radiation levels began to rise. Fallout patterns around Europe and the northern hemisphere were closely tracked. Consequences of the accident in human and monetary terms will require years of evaluation. Although the United States has no power reactors of the Chernobyl type, the country does have a radiation disaster management plan, often rehearsed at the state level. As a consequence of Chernobyl certain international agreements dealing with radiation disaster information and management have been forged.

Accidents↗

PubMed2003

Territory contamination with the radionuclides representing the fuel component of Chernobyl fallout.

The data obtained through a series of experiments were used to specify the correlation of activities of the fuel component radionuclides of Chernobyl fallout and to create the maps of the 30-km Chernobyl zone terrestrial density of contamination with 154Eu, 238Pu, 239+240Pu and 241Am (on 01.01.2000). In the year 2000, total inventories of the fuel component radionuclides in the upper 30-cm soil layer of the 30-km Chernobyl zone in Ukraine (outside the ChNPP industrial site, excluding the activity located in the radioactive waste storages and in the cooling pond) were estimated as: 90Sr--7.7 x 10(14) Bq; 137Cs--2.8 x 10(15) Bq; 154Eu--1.4 x 10(13) Bq; 238Pu--7.2 x 10(12) Bq; 239+240Pu--1.5 x 10(13) Bq; 241Am--1.8 x 10(13) Bq. These values correspond to 0.4-0.5% of their amounts in the ChNPP unit 4 at the moment of the accident. The current estimate is 3 times lower than the previous widely-cited estimates. Inventories of the fuel component radionuclides were also estimated in other objects within the 30-km zone and outside it. This allowed more accurate data to be obtained on the magnitude of a relative release of radionuclides in the fuel particles (FP) matrix during the Chernobyl accident outside the ChNPP industrial site. It amounts to 1.5+/-0.5% of these radionuclides in the reactor, which is 2 times lower than the previous estimates. Two-thirds of the radionuclides release in the FP was deposited on the territory of Ukraine.

Environmental Monitoring↗

PubMed2001

15 years after Chernobyl: new evidence of thyroid cancer.

The Chernobyl nuclear power plant accident happened on April 26, 1986. We investigated the cause of the striking increase in frequency of thyroid cancer in children who lived within a 150 km radius of Chernobyl and who were born before and after the accident. No thyroid cancer was seen in 9472 children born in 1987-89, whereas one and 31 thyroid cancers were recorded in 2409 children born April 27, 1986, to Dec 31, 1986, and 9720 born Jan 1, 1983, to April 26, 1986, respectively. Short-lived radioactive fallout caused by the Chernobyl accident probably induced thyroid cancer in children living near Chernobyl.

Adolescent↗

PubMed2001

Classification of hot particles from the Chernobyl accident and nuclear weapons detonations by non-destructive methods.

Both after the Chernobyl accident and nuclear weapon detonations, agglomerates of radioactive material, so-called hot particles, were released or formed which show a behaviour in the environment quite different from the activity released in gaseous or aerosol form. The differences in their characteristic properties, in the radionuclide composition and the uranium and actinide contents are described in detail for these particles. While nuclear bomb hot particles (both from fission and fusion bombs) incorporate well detectable trace amounts of 60Co and 152Eu, these radionuclides are absent in Chernobyl hot particles. In contrast, Chernobyl hot particles contain 125Sb and 144Ce which are absent in atomic bomb HPs. Obvious differences are also observable between fusion and fission bombs' hot particles (significant differences in 152Eu/l55Eu, 154Eu/155Eu and 238Pu/239Pu ratios) which facilitate the identification of HPs of unknown provensence. The ratio of 239Pu/240Pu in Chernobyl hot particles could be determined by a non-destructive method at 1:1.5. A non-destructive method to determine the content of non-radioactive elements by Kalpha-emission measurements was developed by which inactive Zr, Nb, Fe and Ni could be verified in the particles.

Environmental Monitoring↗