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Abstract
This review summarizes the current knowledge about the general toxicity of thallium (Tl) and its environmental sources, with special emphasis placed on its potential mutagenic, genotoxic, and cytotoxic effects on both eukaryotic and prokaryotic cells. Tl is a nonessential heavy metal that poses environmental and occupational threats as well as therapeutic hazards because of its use in medicine. It is found in two oxidation states, thallous (Tl(+)) and thallic (Tl(3+)), both of which are considered highly toxic to human beings and domestic and wild organisms. Many Tl compounds are colorless, odorless and tasteless, and these characteristics, combined with the high toxicity of TI compounds, have led to their use as poisons. Because of its similarity to potassium ions (K(+)), plants and mammals readily absorb Tl(+) through the skin and digestive and respiratory systems. In mammals, it can cross the placental, hematoencephalic, and gonadal barriers. Inside cells, Tl can accumulate and interfere with the metabolism of potassium and other metal cations, mimicking or inhibiting their action. The effects of Tl on genetic material have not yet been thoroughly explored, and few existing studies have focused exclusively on Tl(+). Both in vivo and in vitro studies indicate that Tl compounds can have a weak mutagenic effect, but no definitive effect on the induction of primary DNA damage or chromosomal damage has been shown. These studies have demonstrated that Tl compounds are highly toxic and lead to changes in cell-cycle progression.
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Affiliation(s)
- Juan José Rodríguez-Mercado
- Unidad de Investigación en Genética y Toxicología Ambiental (UIGTA), Laboratorio L5-PA, Unidad Multidisciplinaria de Investigación Experimental (UMIE-Z), Facultad de Estudios Superiores-Zaragoza, Cuidad de México, México.
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Guiraud-Vitaux F, Jacquet N, Petiet A, Roy L, Voisin P, Colas-Linhart N. Induction of unstable and stable chromosomal aberrations by 99mTc: in-vitro and in-vivo studies. Nucl Med Commun 2005; 26:913-8. [PMID: 16160651 DOI: 10.1097/00006231-200510000-00010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Biological dosimetry, which determines the dose of acquired radiation by measuring radiation-induced variation of biological parameters, can help assess radiation damage in an individual. Evaluation of radiation exposure requires setting up reference curves for each type of radiation. AIM To evaluate the potential induction of chromosome aberrations by a clinical diagnostic dose of 99mTc. METHODS Dicentrics, rings, excess fragments, complete reciprocal translocations and incomplete reciprocal translocations were scored in peripheral blood lymphocytes from patients exposed to a 99mTc bone scintigraphy. A specific relationship between the radiation dose delivered by 99mTc and the frequency of stable and unstable chromosomal aberrations was established in vitro to estimate whole-body dose. Chromosome analysis using fluorescence plus Giemsa and fluorescence in-situ hybridization was undertaken on six patients before and after a 99mTc bone scintigraphy. Dicentrics, rings, excess fragments, and translocations were scored in blood lymphocytes after in vitro 99mTc external irradiation in order to construct dose calibration curves. RESULTS Analysis of the in-vitro data shows that the number of both unstable and stable aberrations has a quadratic linear relationship to the dose. Our in-vivo irradiation studies showed that activities of 99mTc-hexamethylene diphosphonate (99mTc-HDP) used for bone investigations do not induce any additional unstable chromosome aberrations and translocations. The frequencies obtained did not differ significantly from background values. CONCLUSIONS 99mTc can produce unstable and stable chromosomal aberrations in vitro. 99mTc-HDP administration does not induce supplementary chromosomal aberrations. The dose-response curves will allow a more accurate evaluation of the risk related to in-vivo administration of 99mTc labelled radiopharmaceuticals, and they can be used to assess the safe upper limit of injected activity in humans.
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Yildirim M, Ikbal M, Tos T, Seven B, Pirim I, Varoglu E. Genotoxicity of thallium-201 in patients with angina pectoris undergoing myocardial perfusion study. TOHOKU J EXP MED 2005; 206:299-304. [PMID: 15997200 DOI: 10.1620/tjem.206.299] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Thallium-201 (201Tl) has been widely used as a nuclear reagent for myocardial blood flow imaging. The purpose of this study was to investigate genotoxic effects of 201Tl in patients with angina pectoris (n = 21), who had undergone myocardial perfusion imaging. Lymphocytes were isolated from each patient before, and 3, 30 and 90 days after 201Tl administration (111 MBq, 3 mCi) and were analyzed for chromosomal aberrations, sister chromatid exchanges, mitotic index and replicative index. There were significant increases in chromosomal aberrations and sister chromatid exchanges 3 days after 201Tl administration (p < 0.001), although no difference was noted in these values after 30 and 90 days (p > 0.05). Moreover, decreased mitotic index and replicative index were noted after 3 days of 201Tl administration (p < 0.001). These results suggest that the administration of 201Tl for myocardial blood flow imaging may induce genetic damage.
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Affiliation(s)
- Mustafa Yildirim
- Department of Nuclear Medicine, Ataturk University, Medical Faculty, Erzurum, Turkey.
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Affiliation(s)
- Brian G Abbott
- Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, Connecticut 06516, USA.
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Curry J, Karnaoukhova L, Guenette GC, Glickman BW. Influence of sex, smoking and age on human hprt mutation frequencies and spectra. Genetics 1999; 152:1065-77. [PMID: 10388825 PMCID: PMC1460655 DOI: 10.1093/genetics/152.3.1065] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Examination of the literature for hprt mutant frequencies from peripheral T cells yielded data from 1194 human subjects. Relationships between mutant frequency, age, sex, and smoking were examined, and the kinetics were described. Mutant frequency increases rapidly with age until about age 15. Afterward, the rate of increase falls such that after age 53, the hprt mutant frequency is largely stabilized. Sex had no effect on mutant frequency. Cigarette smoking increased mean mutant frequency compared to nonsmokers, but did not alter age vs. mutant frequency relationships. An hprt in vivo mutant database containing 795 human hprt mutants from 342 individuals was prepared. No difference in mutational spectra was observed comparing smokers to nonsmokers, confirming previous reports. Sex affected the frequency of deletions (>1 bp) that are recovered more than twice as frequently in females (P = 0. 008) compared to males. There is no indication of a significant shift in mutational spectra with age for individuals older than 19 yr, with the exception of A:T --> C:G transversions. These events are recovered more frequently in older individuals.
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Affiliation(s)
- J Curry
- Centre for Environmental Health and the Department of Biology, University of Victoria, Victoria, British Columbia V8W 3N5, Canada.
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Abstract
The paper reviews the information available concerning the mutagenic, carcinogenic and teratogenic effects of thallium. Data on mutagenic and carcinogenic risks of thallium and its compounds are extremely scanty but what is available does not indicate that thallium could be mutagenic or carcinogenic. At any rate, such risks, if they exist, would be submerged by the general high toxicity of thallium. On the other hand, thallium has some teratogenic properties, especially on cartilage and bone formation, although this seems to be more prominent in chicks than in mammals. Nevertheless, pregnant women should not be exposed to doses of thallium which might produce toxic symptoms; exposure to lower doses such as might occur near thallium-emitting plants is probably not embryotoxic.
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Affiliation(s)
- A Léonard
- Teratogenicity and Mutagenicity Unit, Catholic University of Louvain, Brussels, Belgium.
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Wones R, Radack K, Martin V, Mandell K, Pinney S, Buncher R. Do persons living near a uranium processing site have evidence of increased somatic cell gene mutations? A first study. Mutat Res 1995; 335:171-84. [PMID: 7477048 DOI: 10.1016/0165-1161(95)90053-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The objective of this study was to examine if individuals living near a uranium processing site have greater mutagenic damage, as measured by three mutagenicity assays, compared with subjects unexposed to any nuclear facilities. The design was a cross-sectional exploratory analysis of 112 subjects; 56 volunteer residents were from within a 5-mile radius of the Fernald Uranium Processing site and 56 'control' subjects were from a geographically separate area unexposed to any known uranium emissions. The groups were constrained to be similar in age and sex composition. The main outcome measures were three human somatic gene mutation assays consisting of the HPRT T-lymphocyte cloning assay to measure 6-thioguanine resistant lymphocytes; the glycophorin A assay to detect the loss of expression of the M or N allele; and the micronucleus assay as a marker of chromosomal damage. The results showed no statistically significant or quantitatively important differences between groups for all three mutagenicity assays; only the unselected cloning efficiency was statistically significantly different between groups (0.42 +/- 0.16 for the Fernald versus 0.35 +/- 0.12 for the comparison groups). In both groups, age was significantly related to HPRT mutant frequency, with a 1.25% rate of increase in mutant frequencies for each 1-year gain of age in the Fernald group and a 1.12% rate of increase in mutant frequencies for each 1-year gain of age in the comparison group. For the micronucleus data, females had a greater mean micronucleus frequency than males. In addition, smokers had an increased mean ln (natural logarithm) HPRT mutant frequency (3.06 +/- 0.14 for current smokers compared with a mean of 2.72 +/- 0.05 for non-current (i.e. never plus former) smokers). Our results are consistent with the previously reported association between sex type and micronucleus frequency, the known relationship between age and T-lymphocyte cloning efficiency and age and HPRT mutant frequency, and verify the wide inter-subject variability for the latter. Finally, we conclude that at a population level, the relationships between current cigarette use and HPRT mutant frequency, and sex type and micronucleus frequency, are stronger than is the association between geographic proximity to a uranium processing site and mutagenic abnormalities.
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Affiliation(s)
- R Wones
- Department of Medicine, University of Cincinnati School of Medicine, OH 45267-0535, USA
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Cole J, Skopek TR. International Commission for Protection Against Environmental Mutagens and Carcinogens. Working paper no. 3. Somatic mutant frequency, mutation rates and mutational spectra in the human population in vivo. Mutat Res 1994; 304:33-105. [PMID: 7506357 DOI: 10.1016/0027-5107(94)90320-4] [Citation(s) in RCA: 176] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- J Cole
- MRC Cell Mutation Unit, University of Sussex, Falmer, Brighton, UK
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Greenstock CL, Trivedi A. Biological and biophysical techniques to assess radiation exposure: a perspective. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1994; 61:81-130. [PMID: 8029472 DOI: 10.1016/0079-6107(94)90007-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Biological dosimeters measure biologically relevant effects of radiation exposure that are in some sense an estimate of effective dose, whereas biophysical indicators serve as surrogates of absorbed dose in a manner analogous to conventional thermoluminescent dosimeters (TLD). The biological and biophysical dosimeters have the potential to play an important role in assessing unanticipated or occupational radiation exposures. For example, where the exposure is large and uncertain (i.e. radiation accidents), accurate dose information can help in deciding the most appropriate therapy and medical treatment. Another useful area is that of lifetime accumulated dose determination, and the ability to distinguish between and integrate the exposures from natural and anthropogenic (medical X-rays, indoor radon, natural background radiation, occupational and non-occupational exposures). Also, the possibility to monitor individual response and differences in inherent or induced radiation sensitivity may have important implications for radiation protection. More commonly, this type of dosimetry could be used for routine monitoring to detect and quantify unsuspected exposure, for regulatory purposes or for epidemiological studies of the long-term effects of radiation exposure (e.g. in Japanese A-bomb survivors or in the population surrounding Chernobyl). This review is a comparative study of the existing techniques and their future prospects. It summarizes the sensitivity, reproducibility, limiting dose, dose-rate, energy, LET response, sources of variability and uncertainty, and other practical aspects of each bio-indicator. The strengths and weaknesses of each approach are evaluated on the basis of common criteria for particular applications, and are summarized for each assay both in the text and in tabular form, for convenience. It is clear that no single indicator qualifies to reliably measure occupational exposures at the current levels of sensitivity conventional dosimetry services provide. Most of the bio-techniques are applicable to the detection of relatively high radiation exposures at relatively short times after exposure. Some of the bio-indicators have been identified that are, or offer future prospects for becoming, appropriate bio-indicators for dosimetry needs. However, all methods are subject to biological and other variables that are presently uncontrolled, and represent a major source of uncertainty. These include variations in background signals not directly associated with radiation exposure, inter- and intra-individual variability of radiation response, and genetic and environmental effects. Although these factors contribute to the lack of confidence in biological dosimetry, promising bio-indicators may be applied to large populations to establish the inherent variability and confounding factors that limit quantitative data collection and analysis, and reduce reliability and reproducibility.
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Affiliation(s)
- C L Greenstock
- Health Sciences and Services Division, AECL Research, Chalk River Laboratories, Ontario, Canada
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Seifert AM, Demers C, Dubeau H, Messing K. HPRT-mutant frequency and lymphocyte characteristics of workers exposed to ionizing radiation on a sporadic basis: a comparison of two exposure indicators, job title and dose. Mutat Res 1993; 319:61-70. [PMID: 7690460 DOI: 10.1016/0165-1218(93)90031-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Using the clonal HPRT-mutant frequency assay, mutant frequencies of humans have been shown to rise following exposure to large doses of mutagens during radiotherapy, chemotherapy or after an atom bomb explosion. Success in relating mutant frequencies to exposure to high levels of mutagens has encouraged researchers to examine the effects of lower doses, such as those found among workers exposed at their jobs. In order to relate low doses of mutagens to biological effects, accurate characterization of exposure is critical, but most occupational studies are forced to use gross measures of exposure derived from job title or professional judgments as to potential exposure. Mutant frequencies and other relevant lymphocyte characteristics of 58 industrial workers were related to exposure status in two ways. When workers were classed as "exposed" or "unexposed" to ionizing radiation, no difference in any biological variable was seen between the two groups. When dosimeter readings were used as the exposure indicator, significant relationships appeared between dose and mutant frequency and CD4/CD8 lymphocyte subpopulation ratios. Mutant frequency was also positively related to age and smoking status. The time course of exposure and of appearance of mutant cells is discussed and it is suggested that this relationship receive attention in occupational studies of genotoxic effects.
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Affiliation(s)
- A M Seifert
- Centre pour l'Etude des Interactions Biologiques entre la Santé et l'Environment (CINBIOSE), Université du Québec à Montréal, Canada
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Radiation-Induced Mutation in Mammalian Cells at Low Doses and Dose Rates. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/b978-0-12-035416-0.50008-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
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Lambert B, Andersson B, He SM, Marcus S, Steen AM. Molecular analysis of mutation in the human gene for hypoxanthine phosphoribosyltransferase. MOLECULAR GENETIC MEDICINE 1992; 2:161-88. [PMID: 1458224 DOI: 10.1016/b978-0-12-462002-5.50011-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- B Lambert
- Department of Clinical Genetics, Karolinska Institute, Stockholm, Sweden
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Kelsey KT, Donohoe KJ, Memisoglu A, Baxter B, Caggana M, Liber HL. In vivo exposure of human lymphocytes to technetium-99m in nuclear medicine patients does not induce detectable genetic effects. Mutat Res 1991; 264:213-8. [PMID: 1723502 DOI: 10.1016/0165-7992(91)90081-e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Recent reports have demonstrated that exposure of nuclear medicine patients to thallium-201 does not result in a detectable increase in mutation at the hprt locus in human lymphocytes. In an effort to study further the potential genetic effects of medical exposures to low dose radiation, we have examined chromosome aberrations and mutations in peripheral blood lymphocytes from nuclear medicine patients exposed to clinical doses of technetium-99m. Our results show that there is no exposure-related increase in chromosomal damage; furthermore, the data do not confirm earlier reports of exposure-related increases in mutations induced by technetium-99m.
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Affiliation(s)
- K T Kelsey
- Laboratory of Radiobiology, Harvard School of Public Health, Boston, MA 02115
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