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Sinha N, Hamre HJ, Musial F, L Werner E, Björkman L. Health complaints before and at one and five years after removal of dental amalgam restorations - data from a prospective cohort study in Norway. Acta Odontol Scand 2024; 83:219-229. [PMID: 38699922 DOI: 10.2340/aos.v83.40260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 01/23/2024] [Indexed: 05/05/2024]
Abstract
OBJECTIVE Health complaints attributed to dental amalgam fillings comprise both intraoral and general health complaints. There are data suggesting that patients with medically unexplained physical symptoms (MUPS) attributed to amalgam fillings show improvement in symptoms after removal of all amalgam fillings. However, data indicating changes of specific health complaints are limited. This study evaluated the changes of health complaints after removal of amalgam restorations in patients with health complaints attributed to dental amalgam fillings. METHOD Patients with MUPS attributed to dental amalgam (Amalgam cohort) had all their amalgam fillings removed. The participants indicated an intensity of 11 local and 12 general health complaints on numeric rating scales before the treatment and at follow-up after 1 and 5 years. The comparison groups comprising a group of healthy individuals and a group of patients with MUPS without symptom attribution to dental amalgam did not have their amalgam restorations removed. RESULTS In the Amalgam cohort, mean symptom intensity was lower for all 23 health complaints at follow-up at 1 year compared to baseline. Statistically significant changes were observed for specific health complaints with effect sizes between 0.36 and 0.68. At the 5-year follow-up, the intensity of symptoms remained consistently lower compared to before the amalgam removal. In the comparison groups, no significant changes of intensity of symptoms of health complaints were observed. CONCLUSION After removal of all amalgam restorations, both local and general health complaints were reduced. Since blinding of the treatment was not possible, specific and non-specific treatment effects cannot be separated.
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Affiliation(s)
- Nivedita Sinha
- Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
| | - Harald Johan Hamre
- Institute for Applied Epistemology and Medical Methodology, University of Witten/Herdecke, Freiburg, Germany
| | - Frauke Musial
- Department of Community Medicine, Faculty of Health Sciences, The National Research Center in Complementary and Alternative Medicine (NAFKAM), UiT The Arctic University of Norway, Tromsø, Norway
| | - Erik L Werner
- Research Unit for General Practice, NORCE Norwegian Research Centre AS, Bergen, Norway; Department of General Practice, Institute of Health and Society, University of Oslo, Oslo, Norway
| | - Lars Björkman
- Dental Biomaterials Adverse Reaction Unit, NORCE Norwegian Research Centre AS, Bergen, Norway.
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El-Sewify IM, Radwan A, Elghazawy NH, Fritzsche W, Azzazy HME. Optical chemosensors for environmental monitoring of toxic metals related to Alzheimer's disease. RSC Adv 2022; 12:32744-32755. [PMID: 36425686 PMCID: PMC9664454 DOI: 10.1039/d2ra05384e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022] Open
Abstract
Alzheimer's disease (AD) is the most common type of dementia and progresses from mild memory loss to severe decline in thinking, behavioral and social skills, which dramatically impairs a person's ability to function independently. Genetics, some health disorders and lifestyle have all been connected to AD. Also, environmental factors are reported as contributors to this illness. The presence of heavy metals in air, water, food, soil and commercial products has increased tremendously. Accumulation of heavy metals in the body leads to serious malfunctioning of bodily organs, specifically the brain. For AD, a wide range of heavy metals have been reported to contribute to its onset and progression and the manifestation of its hallmarks. In this review, we focus on detection of highly toxic heavy metals such as mercury, cadmium, lead and arsenic in water. The presence of heavy metals in water is very troubling and regular monitoring is warranted. Optical chemosensors were designed and fabricated for determination of ultra-trace quantities of heavy metals in water. They have shown advantages when compared to other sensors, such as selectivity, low-detection limit, fast response time, and wide-range determination under optimal sensing conditions. Therefore, implementing optical chemosensors for monitoring levels of toxic metals in water represents an important contribution in fighting AD. This review briefly summarizes evidence that links toxic metals to onset and progression of Alzheimer's disease. It discusses the structure and fabrication of optical chemosensors, and their use for monitoring toxic metals in water.![]()
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Affiliation(s)
- Islam M. El-Sewify
- Department of Chemistry, Faculty of Science, Ain Shams University, 11566, Abbassia, Cairo, Egypt
- Department of Chemistry, School of Sciences & Engineering, The American University in Cairo, SSE, Rm #1194, P.O. Box 74, New Cairo 11835, Egypt
| | - Ahmed Radwan
- Department of Chemistry, Faculty of Science, Ain Shams University, 11566, Abbassia, Cairo, Egypt
- Department of Chemistry, School of Sciences & Engineering, The American University in Cairo, SSE, Rm #1194, P.O. Box 74, New Cairo 11835, Egypt
| | - Nehal H. Elghazawy
- Department of Chemistry, School of Sciences & Engineering, The American University in Cairo, SSE, Rm #1194, P.O. Box 74, New Cairo 11835, Egypt
| | - Wolfgang Fritzsche
- Department of Nanobiophotonics, Leibniz Institute for Photonic Technology, Jena 07745, Germany
| | - Hassan M. E. Azzazy
- Department of Chemistry, School of Sciences & Engineering, The American University in Cairo, SSE, Rm #1194, P.O. Box 74, New Cairo 11835, Egypt
- Department of Nanobiophotonics, Leibniz Institute for Photonic Technology, Jena 07745, Germany
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Bjørklund G, Crisponi G, Nurchi VM, Cappai R, Buha Djordjevic A, Aaseth J. A Review on Coordination Properties of Thiol-Containing Chelating Agents Towards Mercury, Cadmium, and Lead. Molecules 2019; 24:E3247. [PMID: 31489907 PMCID: PMC6767255 DOI: 10.3390/molecules24183247] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/26/2019] [Accepted: 08/31/2019] [Indexed: 11/17/2022] Open
Abstract
The present article reviews the clinical use of thiol-based metal chelators in intoxications and overexposure with mercury (Hg), cadmium (Cd), and lead (Pb). Currently, very few commercially available pharmaceuticals can successfully reduce or prevent the toxicity of these metals. The metal chelator meso-2,3-dimercaptosuccinic acid (DMSA) is considerably less toxic than the classical agent British anti-Lewisite (BAL, 2,3-dimercaptopropanol) and is the recommended agent in poisonings with Pb and organic Hg. Its toxicity is also lower than that of DMPS (dimercaptopropane sulfonate), although DMPS is the recommended agent in acute poisonings with Hg salts. It is suggested that intracellular Cd deposits and cerebral deposits of inorganic Hg, to some extent, can be mobilized by a combination of antidotes, but clinical experience with such combinations are lacking. Alpha-lipoic acid (α-LA) has been suggested for toxic metal detoxification but is not considered a drug of choice in clinical practice. The molecular mechanisms and chemical equilibria of complex formation of the chelators with the metal ions Hg2+, Cd2+, and Pb2+ are reviewed since insight into these reactions can provide a basis for further development of therapeutics.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, N-8610 Mo i Rana, Norway.
| | - Guido Crisponi
- Cittadella Universitaria, University of Cagliari, 09042 Cagliari, Italy.
| | - Valeria Marina Nurchi
- Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy.
| | - Rosita Cappai
- Department of Life and Environmental Sciences, University of Cagliari, 09042 Cagliari, Italy.
| | - Aleksandra Buha Djordjevic
- Department of Toxicology "Akademik Danilo Soldatović", Faculty of Pharmacy, University of Belgrade, 11000 Belgrade, Serbia.
| | - Jan Aaseth
- Research Department, Innlandet Hospital, N-2380 Brumunddal, Norway.
- Inland Norway University of Applied Sciences, N-2411 Elverum, Norway.
- IM Sechenov First Moscow State Medical University (Sechenov University), 119146 Moscow, Russia.
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Bjørklund G, Hilt B, Dadar M, Lindh U, Aaseth J. Neurotoxic effects of mercury exposure in dental personnel. Basic Clin Pharmacol Toxicol 2019; 124:568-574. [PMID: 30589214 DOI: 10.1111/bcpt.13199] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 12/14/2018] [Indexed: 12/29/2022]
Abstract
Numerous studies have reported neurobehavioural effects in dental personnel occupationally exposed to chronic low levels of mercury (Hg). Hg exposure from dental work may also induce various chronic conditions such as elevation of amyloid protein expression, deterioration of microtubules and increase or inhibition of transmitter release at motor nerve terminal endings. Therefore, clinical studies of Hg toxicity in dentistry may provide new knowledge about disturbed metal homeostasis in neurodegenerative diseases such as Alzheimer's disease, multiple sclerosis and mood disorders. The purpose of this MiniReview is to evaluate the evidence of possible relevance between Hg exposure in dentistry and idiopathic disturbances in motor functions, cognitive skills and affective reactions, as well as dose-response relationships.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
| | - Bjørn Hilt
- Department of Occupational Medicine, St. Olav University Hospital, Trondheim, Norway.,Department of Public Health and Nursing, Norwegian University of Science and Technology, Trondheim, Norway
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Ulf Lindh
- Biology Education Centre, Uppsala University, Uppsala, Sweden
| | - Jan Aaseth
- Research Department, Innlandet Hospital Trust, Brumunddal, Norway.,Faculty of Health and Social Science, Inland Norway University of Applied Sciences, Elverum, Norway
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Calabrese EJ, Iavicoli I, Calabrese V, Cory-Slechta DA, Giordano J. Elemental mercury neurotoxicity and clinical recovery of function: A review of findings, and implications for occupational health. ENVIRONMENTAL RESEARCH 2018; 163:134-148. [PMID: 29438899 DOI: 10.1016/j.envres.2018.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/16/2018] [Accepted: 01/17/2018] [Indexed: 06/08/2023]
Abstract
This paper assessed approximately 30 studies, mostly involving occupationally exposed subjects, concerning the extent to which those who developed elemental mercury (Hg)-induced central and/or peripheral neurotoxicities from chronic or acute exposures recover functionality and/or performance. While some recovery occurred in the vast majority of cases, the extent of such recoveries varied considerably by individual and endpoint. Factors accounting for the extensive inter-individual variation in toxicity and recovery were not specifically assessed such as age, gender, diet, environmental enrichment, chelation strategies and dose-rate. While the data indicate that psychomotor endpoints often show substantial and relatively rapid (i.e., 2-6 months) recovery and that neuropsychological endpoints display slower and less complete recovery, generalizations are difficult due to highly variable study designs, use of different endpoints measured between studies, different Hg exposures based on blood/urine concentrations and Hg dose-rates, the poor capacity for replicating findings due to the unpredictable/episodic nature of harmful exposures to elemental Hg, and the inconsistency of the initiation of studies after induced toxicities and the differing periods of follow up during recovery periods. Finally, there is strikingly limited animal model literature on the topic of recovery/reversibility of elemental Hg toxicity, a factor which significantly contributes to the overall marked uncertainties for predicting the rate and magnitude of recovery and the factors that affect it.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, University of Massachusetts, Morrill I, N344, Amherst, MA 01003, USA.
| | - Ivo Iavicoli
- Department of Public Health, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy.
| | - Vittorio Calabrese
- Department of Biomed & Biotech Sciences, School of Medicine, University of Catania, Via Santa Sofia 97, Catania 95125, Italy.
| | - Deborah A Cory-Slechta
- Environmental Medicine, Pediatrics & Public Health Sciences, University of Rochester School of Medicine, Rochester, NY 14642, USA.
| | - James Giordano
- Department of Neurology and Biochemistry, and Neuroethics Studies Program-Pellegrino Center for Clinical Bioethics, Georgetown University Medical Center, Washington, D.C. 20057, USA.
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Geary DC. Evolution of Human Sex-Specific Cognitive Vulnerabilities. QUARTERLY REVIEW OF BIOLOGY 2017. [DOI: 10.1086/694934] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Fields CA, Borak J, Louis ED. Persistence of mercury-induced motor and sensory neurotoxicity: systematic review of workers previously exposed to mercury vapor. Crit Rev Toxicol 2017; 47:845-866. [PMID: 28722535 PMCID: PMC5962347 DOI: 10.1080/10408444.2017.1342599] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 05/16/2017] [Accepted: 06/11/2017] [Indexed: 10/19/2022]
Abstract
Elemental mercury (Hg0) is a well-recognized neurotoxicant, but it is uncertain whether and for how long its neurotoxicity persists. Among studies that evaluated previously-exposed workers, only one examined workers during and also years after exposure had ceased. The objective of this review is to create a series of 'synthetic' longitudinal studies to address the question of persistence of Hg0 neurotoxicity in occupationally exposed workers. We systematically reviewed studies describing objective motor and sensory effects in previously-exposed mercury workers. Data from physical examination (PE), neurobehavioral (NB) tests, and electrophysiological studies (EPS) were extracted into structured tables and examined for their consistency and dose-relatedness and then compared with the corresponding results from studies of currently exposed workers. We identified six cohorts that described neurological findings in 1299 workers, examined an average of 4.8-30 years after the cessation of exposure. Historical group mean UHg levels ranged from 23 to >500 μg/L, with UHg levels >6000 μg/L in some individuals. Overall, few findings were significant; most were inconsistent across the previous-exposure studies, and in comparisons between studies of previously and currently exposed workers. The results of this systematic review indicate that Hg0-related neurotoxic effects detectable on PE, NB testing, and EPS are substantially reversed over time. To the extent that such effects do persist, they are reported principally in workers who have had very high-dose exposures. In addition, based on the limited available data, those effects reported to persist have been described as having little or no functional significance.
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Affiliation(s)
- Cheryl A. Fields
- Department of Environmental Health Sciences, Yale School of Public Health, New Haven, Connecticut, USA
| | - Jonathan Borak
- Departments of Medicine and Epidemiology & Public Health, Yale School of Medicine, New Haven, Connecticut, USA
| | - Elan D. Louis
- Department of Neurology, Yale School of Medicine, and Department of Chronic Disease Epidemiology, Yale School of Public Health, New Haven, Connecticut, USA
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8
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Milioni ALV, Nagy BV, Moura ALA, Zachi EC, Barboni MT, Ventura DF. Neurotoxic impact of mercury on the central nervous system evaluated by neuropsychological tests and on the autonomic nervous system evaluated by dynamic pupillometry. Neurotoxicology 2017; 59:263-269. [DOI: 10.1016/j.neuro.2016.04.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 04/09/2016] [Accepted: 04/11/2016] [Indexed: 11/25/2022]
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9
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Fell AKM, Eikeland R, Aaseth JO. En kvinne i 30-årene med hoste, tremor, uro og synsforstyrrelser. TIDSSKRIFT FOR DEN NORSKE LEGEFORENING 2016; 136:1233-5. [DOI: 10.4045/tidsskr.15.0998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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10
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van Wijk CH, Meintjes WAJ. Grooved Pegboard for adult employed South Africans: normative data and human immunodeficiency virus associations. SOUTH AFRICAN JOURNAL OF PSYCHOLOGY 2015. [DOI: 10.1177/0081246315587692] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The Grooved Pegboard is a widely used test of psychomotor speed, and currently is used in particular to assess HIV-associated neurocognitive decline. To accurately interpret any assessment, appropriate reference norms are required. Although South Africa has the highest number of people living with HIV and AIDS, no local large scale reference data are available for the Grooved Pegboard. The main objective of the study was to formulate reference data for healthy adult South Africans in formal employment; two secondary objectives aimed to statistically explore the available Grooved Pegboard performance data, as well as its association with HIV status. Data were collected as part of multi-disciplinary occupational health screening, and included healthy HIV− adults ( N = 3118), and 70 HIV+ participants. This article presents normative reference data stratified across age and gender categories. The South African scores differ from other reported samples, emphasising the need to develop local norms that are context based, to facilitate clinical interpretation of psychomotor performance. Furthermore, in this sample, the Grooved Pegboard differentiated significantly between asymptomatic HIV+ persons, and those with HIV-associated neurocognitive disorders, although with poor predictive ability. In conclusion, large-sample reference data for healthy employed adult South Africans (age 19–59) are reported across gender and age categories, and may assist in more accurate screening of psychomotor speed generally, and HIV-associated neurocognitive decline in particular.
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Affiliation(s)
- Charles H van Wijk
- Division of Community Health, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
- Institute for Maritime Medicine, South Africa
| | - WAJ Meintjes
- Division of Community Health, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
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Li WC, Tse HF. Health risk and significance of mercury in the environment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:192-201. [PMID: 25220768 DOI: 10.1007/s11356-014-3544-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 09/01/2014] [Indexed: 06/03/2023]
Abstract
Mercury (Hg) has long been recognised as a global pollutant, because it can remain in the atmosphere for more than 1 year. The mercury that enters the environment is generally acknowledged to have two sources: natural and anthropogenic. Hg takes three major forms in the environment, namely methyl-Hg (MeHg), Hg(0) and Hg(2+). All three forms of Hg adversely affect the natural environment and pose a risk to human health. In particular, they may damage the human central nervous system, leading to cardiovascular, respiratory and other diseases. MeHg is bioavailable and can be bioaccumulated within food webs. Therefore, several methods of eliminating Hg from the soil and the aquatic system have been proposed. The focus of this article is on phytoremediation, as this technique provides a low-cost and environmentally friendly alternative to traditional methods.
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Affiliation(s)
- W C Li
- Centre for Education in Environmental Sustainability and Department of Science and Environmental Studies, The Hong Kong Institute of Education, 10 Lo Ping Road, Tai Po, New Territories, Hong Kong, SAR, China,
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Steckling N, Bose-O’Reilly S, Pinheiro P, Plass D, Shoko D, Drasch G, Bernaudat L, Siebert U, Hornberg C. The burden of chronic mercury intoxication in artisanal small-scale gold mining in Zimbabwe: data availability and preliminary estimates. Environ Health 2014; 13:111. [PMID: 25495641 PMCID: PMC4290131 DOI: 10.1186/1476-069x-13-111] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 12/04/2014] [Indexed: 05/24/2023]
Abstract
BACKGROUND Artisanal small-scale gold mining (ASGM) is a poverty-driven activity practiced in over 70 countries worldwide. Zimbabwe is amongst the top ten countries using large quantities of mercury to extract gold from ore. This analysis was performed to check data availability and derive a preliminary estimate of disability-adjusted life years (DALYs) due to mercury use in ASGM in Zimbabwe. METHODS Cases of chronic mercury intoxication were identified following an algorithm using mercury-related health effects and mercury in human specimens. The sample prevalence amongst miners and controls (surveyed by the United Nations Industrial Development Organization in 2004 and the University of Munich in 2006) was determined and extrapolated to the entire population of Zimbabwe. Further epidemiological and demographic data were taken from the literature and missing data modeled with DisMod II to quantify DALYs using the methods from the Global Burden of Disease (GBD) 2004 update published by the World Health Organization (WHO). While there was no disability weight (DW) available indicating the relative disease severity of chronic mercury intoxication, the DW of a comparable disease was assigned by following the criteria 1) chronic condition, 2) triggered by a substance, and 3) causing similar health symptoms. RESULTS Miners showed a sample prevalence of 72% while controls showed no cases of chronic mercury intoxication. Data availability is very limited why it was necessary to model data and make assumptions about the number of exposed population, the definition of chronic mercury intoxication, DW, and epidemiology. If these assumptions hold, the extrapolation would result in around 95,400 DALYs in Zimbabwe's total population in 2004. CONCLUSIONS This analysis provides a preliminary quantification of the mercury-related health burden from ASGM based on the limited data available. If the determined assumptions hold, chronic mercury intoxication is likely to have been one of the top 20 hazards for population health in Zimbabwe in 2004 when comparing with more than 130 categories of diseases and injuries quantified in the WHO's GBD 2004 update. Improving data quality would allow more accurate estimates. However, the results highlight the need to reduce a burden which could be entirely avoided.
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Affiliation(s)
- Nadine Steckling
- />Department Environment & Health, Bielefeld University, School of Public Health, Universitätsstraße 25, D-33615 Bielefeld, Germany
- />University Hospital Munich, Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, WHO Collaborating Centre for Occupational Health, Workgroup Paediatric Environmental Epidemiology, Ziemssenstr. 1, D-80336 Munich, Germany
- />UMIT - University for Health Sciences, Medical Informatics and Technology, Department of Public Health and Health Technology Assessment, Institute of Public Health, Medical Decision Making and Health Technology Assessment, Eduard Wallnoefer Center I, A-6060 Hall i.T., Austria
| | - Stephan Bose-O’Reilly
- />University Hospital Munich, Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, WHO Collaborating Centre for Occupational Health, Workgroup Paediatric Environmental Epidemiology, Ziemssenstr. 1, D-80336 Munich, Germany
- />UMIT - University for Health Sciences, Medical Informatics and Technology, Department of Public Health and Health Technology Assessment, Institute of Public Health, Medical Decision Making and Health Technology Assessment, Eduard Wallnoefer Center I, A-6060 Hall i.T., Austria
| | - Paulo Pinheiro
- />Bielefeld University, Faculty of Educational Sciences, Universitätsstraße 25, D-33615 Bielefeld, Germany
| | - Dietrich Plass
- />Federal Environment Agency, Section Exposure Assessment and Environmental Health Indicators, Corrensplatz 1, D-14195 Berlin, Germany
| | - Dennis Shoko
- />Tailjet Consultancy Services, 4 Tor Road, Vainona, Borrowdale, Harare Zimbabwe
| | - Gustav Drasch
- />Institute of Forensic Medicine, Department of Forensic Toxicology, University of Munich - LMU, Nussbaumstr. 26, D-80336 Munich, Germany
| | - Ludovic Bernaudat
- />United Nations Industrial Development Organization, Vienna International Centre, P.O. Box 300, A-1400 Vienna, Austria
| | - Uwe Siebert
- />UMIT - University for Health Sciences, Medical Informatics and Technology, Department of Public Health and Health Technology Assessment, Institute of Public Health, Medical Decision Making and Health Technology Assessment, Eduard Wallnoefer Center I, A-6060 Hall i.T., Austria
- />Harvard Medical School, Massachusetts General Hospital, Institute for Technology Assessment and Department of Radiology, Boston, USA
- />Harvard School of Public Health, Department of Health Policy and Management, Center for Health Decision Science, Boston, USA
| | - Claudia Hornberg
- />Department Environment & Health, Bielefeld University, School of Public Health, Universitätsstraße 25, D-33615 Bielefeld, Germany
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Abstract
STUDY OBJECTIVES To examine episodic memory performance in individuals with obstructive sleep apnea (OSA). DESIGN Meta-analysis was used to synthesize results from individual studies examining the impact of OSA on episodic memory performance. The performance of individuals with OSA was compared to healthy controls or normative data. PARTICIPANTS Forty-two studies were included, comprising 2,294 adults with untreated OSA and 1,364 healthy controls. Studies that recorded information about participants at baseline prior to treatment interventions were included in the analysis. MEASUREMENTS PARTICIPANTS WERE ASSESSED WITH TASKS THAT INCLUDED A MEASURE OF EPISODIC MEMORY: immediate recall, delayed recall, learning, and/or recognition memory. RESULTS The results of the meta-analyses provide evidence that individuals with OSA are significantly impaired when compared to healthy controls on verbal episodic memory (immediate recall, delayed recall, learning, and recognition) and visuo-spatial episodic memory (immediate and delayed recall), but not visual immediate recall or visuo-spatial learning. When patients were compared to norms, negative effects of OSA were found only in verbal immediate and delayed recall. CONCLUSIONS This meta-analysis contributes to understanding of the nature of episodic memory deficits in individuals with OSA. Impairments to episodic memory are likely to affect the daily functioning of individuals with OSA.
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Affiliation(s)
- Anna Wallace
- School of Psychology, University of Western Australia, Perth, Australia
| | - Romola S. Bucks
- School of Psychology, University of Western Australia, Perth, Australia
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Sletvold H, Svendsen K, Aas O, Syversen T, Hilt B. Neuropsychological function and past exposure to metallic mercury in female dental workers. Scand J Psychol 2011; 53:136-43. [PMID: 22092046 PMCID: PMC3412222 DOI: 10.1111/j.1467-9450.2011.00929.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The aim of this study was to see if dental personnel with previous exposure to metallic mercury have later developed disturbances in cognitive function. Ninety-one female participants who had been selected from a previous health survey of dental personnel were investigated neuropsychologically within the following domains: motor function, short-term memory, working memory, executive function, mental flexibility, and visual and verbal long-term memory. The scores were mainly within normal ranges. Relationships between an exposure score, the duration of employment before 1990, and previously measured mercury in urine as independent variables and the neuropsychological findings as dependent variables, were analyzed by multiple linear regression controlling for age, general ability, length of education, alcohol consumption, and previous head injuries. The only relationship that was statistically significant in the hypothesized direction was between the previously measured urine mercury values and visual long-term memory, where the urine values explained 30% of the variability. As the study had a low statistical power and also some other methodological limitations, the results have to be interpreted with caution. Even so, we think it is right to conclude that neuropsychological findings indicative of subsequent cognitive injuries are difficult to find in groups of otherwise healthy dental personnel with previous occupational exposure to mercury.
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Affiliation(s)
- Helge Sletvold
- Department of Industrial Economics and Technology Management, Norwegian University of Science and Technology, Trondheim, Norway
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Mutter J. Is dental amalgam safe for humans? The opinion of the scientific committee of the European Commission. J Occup Med Toxicol 2011; 6:2. [PMID: 21232090 PMCID: PMC3025977 DOI: 10.1186/1745-6673-6-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 01/13/2011] [Indexed: 01/06/2023] Open
Abstract
It was claimed by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR)) in a report to the EU-Commission that "....no risks of adverse systemic effects exist and the current use of dental amalgam does not pose a risk of systemic disease..." [1, available from: http://ec.europa.eu/health/ph_risk/committees/04_scenihr/docs/scenihr_o_016.pdf].SCENIHR disregarded the toxicology of mercury and did not include most important scientific studies in their review. But the real scientific data show that:(a) Dental amalgam is by far the main source of human total mercury body burden. This is proven by autopsy studies which found 2-12 times more mercury in body tissues of individuals with dental amalgam. Autopsy studies are the most valuable and most important studies for examining the amalgam-caused mercury body burden.(b) These autopsy studies have shown consistently that many individuals with amalgam have toxic levels of mercury in their brains or kidneys.(c) There is no correlation between mercury levels in blood or urine, and the levels in body tissues or the severity of clinical symptoms. SCENIHR only relied on levels in urine or blood.(d) The half-life of mercury in the brain can last from several years to decades, thus mercury accumulates over time of amalgam exposure in body tissues to toxic levels. However, SCENIHR state that the half-life of mercury in the body is only "20-90 days".(e) Mercury vapor is about ten times more toxic than lead on human neurons and with synergistic toxicity to other metals.(f) Most studies cited by SCENIHR which conclude that amalgam fillings are safe have severe methodical flaws.
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Affiliation(s)
- Joachim Mutter
- Department of Environmental and integrative medicine Lohnerhofstraße 2, 78467 Constance/Germany.
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Garnier R. Risque de cancer dans l’industrie de production du chlore et de soude caustique par électrolyse ? ARCH MAL PROF ENVIRO 2009. [DOI: 10.1016/j.admp.2008.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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Kobal AB, Prezelj M, Horvat M, Krsnik M, Gibicar D, Osredkar J. Glutathione level after long-term occupational elemental mercury exposure. ENVIRONMENTAL RESEARCH 2008; 107:115-23. [PMID: 17706633 DOI: 10.1016/j.envres.2007.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 05/15/2007] [Accepted: 07/03/2007] [Indexed: 05/16/2023]
Abstract
Many in vitro and in vivo studies have elucidated the interaction of inorganic mercury (Hg) and glutathione. However, human studies are limited. In this study, we investigated the potential effects of remote long-term intermittent occupational elemental Hg vapour (Hg degrees ) exposure on erythrocyte glutathione levels and some antioxidative enzyme activities in ex-mercury miners in the period after exposure. The study included 49 ex-mercury miners divided into subgroups of 28 still active, Hg degrees -not-exposed miners and 21 elderly retired miners, and 41 controls, age-matched to the miners subgroup. The control workers were taken from "mercury-free works". Reduced glutathione (GSH) and oxidized disulphide glutathione (GSSG) concentrations in haemolysed erythrocytes were determined by capillary electrophoresis, while total glutathione (total GSH) and the GSH/GSSG ratio were calculated from the determined values. Catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities in erythrocytes were measured using commercially available reagent kits, while urine Hg (U-Hg) concentrations were determined by cold vapour atomic absorption (CVAAS). No correlation of present U-Hg levels, GSH, GSSG, and antioxidative enzymes with remote occupational biological exposure indices were found. The mean CAT activity in miners and retired miners was significantly higher (p<0.05) than in the controls. No differences in mean GPx activity among the three groups were found, whereas the mean GR activity was significantly higher (p<0.05) in miners than in retired miners. The mean concentrations of GSH (mmol/g Hb) in miners (13.03+/-3.71) were significantly higher (p<0.05) than in the control group (11.68+/-2.66). No differences in mean total GSH, GSSG levels, and GSH/GSSG ratio between miners and controls were found. A positive correlation between GSSG and present U-Hg excretion (r=0.41, p=0.001) in the whole group of ex-mercury miners was observed. The significantly lower GSH level (p<0.05) determined in the group of retired miners (9.64+/-1.45) seems to be age-related (r= -0.39, p=0.001). Thus, the moderate but significantly increased GSH level, GR and CAT activity in erythrocytes in the subgroup of miners observed in the period after exposure to Hg degrees could be an inductive and additive response to maintain the balance between GSH and antioxidative enzymes in interaction with the Hg body burden accumulated during remote occupational exposure, which does not represent a severely increased oxidative stress.
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Affiliation(s)
- Alfred Bogomir Kobal
- University Medical Centre Ljubljana, Institute of Clinical Chemistry and Biochemistry, Njegoseva 4, SI-1525 Ljubljana, Slovenia.
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Zachi EC, Taub A, Faria MDAM, Ventura DF. Neuropsychological alterations in mercury intoxication persist several years after exposure. Dement Neuropsychol 2008; 2:91-95. [PMID: 29213549 PMCID: PMC5619576 DOI: 10.1590/s1980-57642009dn20200003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Accepted: 05/21/2008] [Indexed: 11/22/2022] Open
Abstract
Elemental mercury is a liquid toxic metal widely used in industry. Occupational exposure occurs mainly via inhalation. Previously, neuropsychological assessment detected deficits in former workers of a fluorescent lamp plant who had been exposed to elemental mercury vapor and were away from exposure for several years at the time of examination. OBJECTIVES The purpose of this work was to reexamine these functions after 18 months in order to evaluate their progression. METHODS Thirteen participants completed tests of attention, inhibitory control, verbal/visual memory, psychomotor speed, verbal fluency, visuomotor ability, executive function, semantic knowledge, and depression and anxiety inventories on 2 separate occasions. RESULTS At baseline, the former workers indicated slower psychomotor and information processing speed, verbal spontaneous recall memory impairment, and increased depression and anxiety symptoms compared to controls (P<0.05). Paired comparisons of neuropsychological functioning within the exposed group at baseline and 1.5 years later showed poorer immediate memory performance (P<0.05). There were no differences on other measures. CONCLUSIONS Although the literature show signs of recovery of functions, the neuropsychological effects related to mercury exposure are found to persist for many years.
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Affiliation(s)
- Elaine Cristina Zachi
- M.Sc. Departamento de Psicologia Experimental,
Núcleo de Neurociências e Comportamento, Instituto de Psicologia,
Universidade de São Paulo, São Paulo SP, Brazil
| | - Anita Taub
- M.Sc. Instituto de Psiquiatria da Universidade de
São Paulo, São Paulo SP, Brazil
| | - Marcília de Araújo Medrado Faria
- Ph.D. Departamento de Medicina Legal, Ética
Médica e Medicina Social e do Trabalho, Faculdade de Medicina, Universidade
de São Paulo, São Paulo SP, Brazil
| | - Dora Fix Ventura
- Ph.D. Departamento de Psicologia Experimental,
Núcleo de Neurociências e Comportamento, Instituto de Psicologia,
Universidade de São Paulo, São Paulo SP, Brazil
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Wastensson G, Lamoureux D, Sällsten G, Beuter A, Barregård L. Quantitative assessment of neuromotor function in workers with current low exposure to mercury vapor. Neurotoxicology 2008; 29:596-604. [PMID: 18452994 DOI: 10.1016/j.neuro.2008.03.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 02/22/2008] [Accepted: 03/05/2008] [Indexed: 11/19/2022]
Abstract
Evaluation of neuromotor function has been used in several epidemiological studies of workers with long-term exposure to mercury vapor (Hg 0). Some recent studies indicate adverse effects at relatively low exposure levels. In the present study, we used sensitive quantitative methods, developed specifically to detect subtle effects of exposure to toxins on motor function. After exclusion of individuals with neurological diseases or other conditions that may affect performance, 43 chloralkali workers with current low exposure to Hg 0, and 22 age-matched referents remained for further analysis. The median urinary mercury concentration in exposed workers was 5.9 microg/g (range 1.3-25) creatinine (microg/gC), while that in referents was 0.7 microg/gC (range 0.2-4.1). The mean exposure time was 15 years, and the median cumulative mercury index was 161 years x microg/gC in exposed workers. A eurythmokinesimeter (EKM) was used to quantify eye-hand coordination, and a diadochokinesimeter, to measure rapid alternating rotation of the forearms. In general, the differences in performance between the exposed workers and the referents were small. Age was associated with a decrease in speed, more tremor, and longer contact duration between the stylus and the metal targets in performance of rapid pointing movements. Smokers had significantly more tremor, and more contacts per event in the EKM test, than nonsmokers. Taking age, shift work, and smoking habits into account, no significant associations with current or cumulative mercury exposure were found for the majority of the outcome variables from the quantitative tests. In general, this study indicates no significant adverse effects of Hg 0 on neuromotor function at the exposure levels studied.
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Affiliation(s)
- Gunilla Wastensson
- Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, and University of Göteborg, Box 414, Göteborg, Sweden.
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Zachi EC, D F V, Faria MAM, Taub A. Neuropsychological dysfunction related to earlier occupational exposure to mercury vapor. Braz J Med Biol Res 2007; 40:425-33. [PMID: 17334541 DOI: 10.1590/s0100-879x2007000300019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Accepted: 01/19/2007] [Indexed: 11/21/2022] Open
Abstract
We assessed the neuropsychological test performances of 26 patients (mean age = 41.5 +/- 6.1 years; mean years of education = 9.8 +/- 1.8; 20 males) diagnosed with chronic occupational mercurialism who were former workers at a fluorescent lamp factory. They had been exposed to elemental mercury for an average of 10.2 +/- 3.8 years and had been away from this work for 6 +/- 4.7 years. Mean urinary mercury concentrations 1 year after cessation of work were 1.8 +/- 0.9 microg/g creatinine. Twenty control subjects matched for age, gender, and education (18 males) were used for comparison. Neuropsychological assessment included attention, inhibitory control, verbal and visual memory, verbal fluency, manual dexterity, visual-spatial function, executive function, and semantic knowledge tests. The Beck Depression Inventory and the State and Trait Inventory were used to assess depression and anxiety symptoms, respectively. The raw score for the group exposed to mercury indicated slower information processing speed, inferior performance in psychomotor speed, verbal spontaneous recall memory, and manual dexterity of the dominant hand and non-dominant hand (P < 0.05). In addition, the patients showed increased depression and anxiety symptoms (P < 0.001). A statistically significant correlation (Pearson) was demonstrable between mean urinary mercury and anxiety trait (r = 0.75, P = 0.03). The neuropsychological performances of the former workers suggest that occupational exposure to elemental mercury has long-term effects on information processing and psychomotor function, with increased depression and anxiety also possibly reflecting the psychosocial context.
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Affiliation(s)
- E C Zachi
- Instituto de Psicologia e Núcleo de Neurociências e Comportamento, Faculdade de Medicina, Universidade de São Paulo, Av. Prof. Mello Moraes 1721, 05508-900 São Paulo, SP, Brazil.
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21
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Wastensson G, Lamoureux D, Sällsten G, Beuter A, Barregård L. Quantitative tremor assessment in workers with current low exposure to mercury vapor. Neurotoxicol Teratol 2006; 28:681-93. [PMID: 17056227 DOI: 10.1016/j.ntt.2006.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 08/30/2006] [Accepted: 09/04/2006] [Indexed: 11/29/2022]
Abstract
Measurement of tremor has been used in several occupational studies of workers with long-term exposure to mercury vapor (Hg(0)). Recent studies indicate an adverse effect even at relatively low exposure levels. In the present study, we used sensitive quantitative methods to assess tremor in chloralkali workers with current low exposure to Hg(0). Neurological examinations and recordings of tremor using both an accelerometer and a laser-based system were conducted in 43 mercury-exposed workers and 22 age-matched referents. The median urinary mercury concentration in exposed workers was 5.9 (1.3-25) microg/g creatinine (microg/gC), while it was 0.7 (0.2-4.1) microg/gC in referents. The mean exposure time was 15 years, and the median cumulative mercury index was 161 years x microg/gC in exposed workers. There were no differences between the exposed workers and the referents in the clinical evaluation of tremor. In the quantitative tremor tests, no associations were found with current or cumulative mercury exposure for the majority of tremor measures. There were indications that exposure to Hg(0) was associated with a lowering of tremor frequency in the non-dominant hand, and a possible interaction with smoking. The differences were small, however, and overall, this study indicates no significant adverse effects on tremor at these exposure levels.
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Affiliation(s)
- Gunilla Wastensson
- Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, University of Göteborg, Box 414, SE-405 30 Göteborg, Sweden.
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22
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Rohling ML, Demakis GJ. A Meta-Analysis of the Neuropsychological Effects of Occupational Exposure to Mercury. Clin Neuropsychol 2006; 20:108-32. [PMID: 16393923 DOI: 10.1080/13854040500203324] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
This paper reports a meta-analysis of 36 peer-reviewed published studies of the neuropsychological effects of occupational exposure to mercury, which yielded 43 independent samples. These studies included 2,512 exposed participants and 1,846 controls, for a total sample size of 4,358. Because the independent variables defining mercury exposure varied across studies, effect sizes were calculated for exposed versus non-exposed workers. Dose-response relations were considered for measures of mercury levels in urine (81% of studies reported), blood (42% of studies reported), and air samples (33% of studies reported). Level of exposure was also estimated by reported years of exposure (M = 11.3, SD = 5.6). Cohen's d statistic yielded a statistically significant weighted study-mean effect size of -.23, p < .0001 for occupational mercury exposure. However, an effect this small is typically undetectable when evaluating individuals because it is smaller than the typical 95% confidence interval used for most neuropsychological measures. None of the exposure variables analyzed reached statistical significance. The magnitude of self-reported symptoms (-.30) was slightly larger than that obtained from objective test scores (-.22), though the difference was not statistically significant. Also, the weighted mean effect size for psychomotor skills (-.34) was the largest in magnitude, whereas the weighted mean effect size for verbal comprehension measures had the smallest (-.06). However, an analysis of the differential effects of mercury exposure across cognitive domains found significant differences between verbal comprehension measures and all other domains. None of the other domains were significantly different from one another. The weighted study-mean effect size suggests that the prevalence of neuropsychological deficits due to occupational exposure to mercury is small and difficult to detect on an individual case-by-case basis.
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Affiliation(s)
- Martin L Rohling
- Department of Psychology, University of South Alabama, Mobile, AL 36688-0002, USA.
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Kobal Grum D, Kobal AB, Arneric N, Horvat M, Zenko B, Dzeroski S, Osredkar J. Personality traits in miners with past occupational elemental mercury exposure. ENVIRONMENTAL HEALTH PERSPECTIVES 2006; 114:290-6. [PMID: 16451870 PMCID: PMC1367847 DOI: 10.1289/ehp.7863] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Accepted: 06/14/2005] [Indexed: 05/03/2023]
Abstract
In this study, we evaluated the impact of long-term occupational exposure to elemental mercury vapor (Hg0) on the personality traits of ex-mercury miners. Study groups included 53 ex-miners previously exposed to Hg0 and 53 age-matched controls. Miners and controls completed the self-reporting Eysenck Personality Questionnaire and the Emotional States Questionnaire. The relationship between the indices of past occupational exposure and the observed personality traits was evaluated using Pearson's correlation coefficient and on a subgroup level by machine learning methods (regression trees). The ex-mercury miners were intermittently exposed to Hg0 for a period of 7-31 years. The means of exposure-cycle urine mercury (U-Hg) concentrations ranged from 20 to 120 microg/L. The results obtained indicate that ex-miners tend to be more introverted and sincere, more depressive, more rigid in expressing their emotions and are likely to have more negative self-concepts than controls, but no correlations were found with the indices of past occupational exposure. Despite certain limitations, results obtained by the regression tree suggest that higher alcohol consumption per se and long-term intermittent, moderate exposure to Hg0 (exposure cycle mean U-Hg concentrations > 38.7 < 53.5 microg/L) in interaction with alcohol remain a plausible explanation for the depression associated with negative self-concept found in subgroups of ex-mercury miners. This could be one of the reason for the higher risk of suicide among miners of the Idrija Mercury Mine in the last 45 years.
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Affiliation(s)
- Darja Kobal Grum
- Department of Psychology, Faculty of Arts, University of Ljubljana, Slovenia.
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24
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Taub A, Zachi EC, Teixeira RAA, Faria MDAM, Ventura DF. A aplicação da neuropsicologia na pesquisa experimental: o exemplo da intoxicação por vapor de mercúrio. PSICOLOGIA USP 2006. [DOI: 10.1590/s0103-65642006000400015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
O desenvolvimento da neuropsicologia acompanhou a evolução do estudo do cérebro desde os registros mais antigos. A ciência neuropsicológica faz uso de medidas quantitativas de desempenho e tecnologias para produção de neuroimagem que, em conjunto, permitem a observação das relações cérebro-comportamento. No âmbito experimental, a neuropsicologia tem revelado novos conhecimentos na investigação de alterações cognitivas, psicomotoras ou comportamentais associadas a patologias congênitas ou adquiridas. No presente artigo são abordados aspectos históricos da neuropsicologia experimental e apresentados os principais resultados de um estudo referente às alterações neuropsicológicas de pacientes com histórico de intoxicação por vapor de mercúrio, presentes anos após o período de exposição ao metal.
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25
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Abstract
Memory and psychophysiological variables in persons with self-reported reactions to dental amalgam (amalgam patients: N=26) and in persons without such symptoms (controls: N=21) were compared. The groups were matched regarding age, education, and amount of amalgam. Wechsler Memory Scale-Revised was obtained for all subjects and compared to amalgam points in a dose-response design. The results demonstrated that amalgam patients function on the same level as the controls regarding memory variables, attention, concentration, and delayed recall. Psychophysiological measures of skin conductance as correlates of attention and basal memory functions, were compared in the two groups. No differences between the two groups were observed and no correlation between memory variables and exposure to amalgam could be detected.
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Affiliation(s)
- K Dalen
- Department of Clinical Neuropsychology, University of Bergen, Jonas Liesvei 91, N-5009, Bergen, Norway.
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26
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Lucchini R, Calza S, Camerino D, Carta P, Decarli A, Parrinello G, Soleo L, Zefferino R, Alessio L. Application of a latent variable model for a multicenter study on early effects due to mercury exposure. Neurotoxicology 2003; 24:605-16. [PMID: 12900073 DOI: 10.1016/s0161-813x(03)00048-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A latent variable model was applied to the results of an Italian multicenter nation-wide cross-sectional study to assess the earliest health effects due to mercury (Hg) exposure caused by occupation, dental amalgams (DENTAM) and fish eating (FISH). The studied population included subjects recruited from four different geographical areas. A total number of 122 workers from chloroalkali plants and production of thermometers and neon lamps formed the occupationally exposed group, whereas 196 subjects, recruited from the same areas and not occupationally exposed to mercury, formed the control group. Neuropsychological functions were assessed with neurobehavioral testing including vigilance, motor and cognitive function, tremor measurements, and with symptoms concerning neuropsychological and mood assessment. Neuroendocrine function was examined with the measurement of prolactin (PRL) level. Parameters of immunological and renal function were also measured. The target population was characterized by the number and surface of dental amalgams and consumption of fish. In the exposed workers the average urinary mercury (U-Hg) was 10.4+/-6.9 (geometric mean 8.3, range 0.2-35.2) microg/g creatinine, whereas in the control group it was 1.9+/-2.8 (geometric mean 1.2, range 0.1-33.2) microg/g creatinine. The preliminary results indicated that finger tapping (FT) and the Branches alternate movement task (BAMT) coordination test were associated with the occupational exposure (OCCEXP). PRL was significantly decreased among the exposed workers, and inversely related to U-Hg. Among the immunological and renal parameters, cytokine serum interleuchin-8 (sIL8) and beta(2) micro globulin (beta(2)MG) were lower in the exposed group and negatively correlated to U-Hg. Small-size fish consumption was associated to a beneficial effect on symptoms reporting. No effects were observed concerning dental amalgams. After first evaluating the relationship between mercury exposure and each indicator of effect, further assessment was performed to identify the earliest effects related to mercury exposure among those who resulted in being associated in the preliminary elaboration. Two latent variables "exposure" and "effect" were identified, integrating respectively the different forms of exposure (occupational, due to dental amalgams and fish consumption) and the indicators of effects (FT, BAMT, PRL, sIL8, beta(2)MG). Confounding factors (age, alcohol, body mass index (BMI)) were considered in the same model. This further analysis showed that an inverse association of occupational exposure to mercury with PRL and BAMT, with Hg-U mediating the effect on PRL, was predominant with respect to the other form of mercury exposure, the other indicators of effect and the confounders. In conclusion, this study supports the finding of alterations of neuroendocrine secretion and motor coordination at very low occupational exposure levels of inorganic mercury, below the current ACGIH Biological Exposure Index. These changes occur at lower levels than other subtle effects on the renal function and the immunitary system. On the contrary, dental amalgams and small-size fish consumption do not seem to be associated to any adverse health effect at these exposure levels.
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Affiliation(s)
- Roberto Lucchini
- Institute of Occupational Health and Industrial Hygiene, University of Brescia, Brescia, Italy.
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27
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Ellingsen DG, Bast-Pettersen R, Efskind J, Thomassen Y. Neuropsychological effects of low mercury vapor exposure in chloralkali workers. Neurotoxicology 2001; 22:249-58. [PMID: 11405256 DOI: 10.1016/s0161-813x(01)00012-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Neuropsychological effects were examined in 47 mercury vapor exposed male chloralkali workers with current low concentrations of urinary mercury (mean U-Hg 5.9 nmol/mmol creatinine (Cr)). Their average duration of exposure was 13.3 years, and the calculated mean concentration of U-Hg was 9.0 nmol Hg/mmol Cr per year (exposure intensity) during their time of exposure. They were compared with 47 age-matched male referents in a cross-sectional study. The two groups were not statistically significantly different with respect to neuropsychological test performance or number of self-reported subjective symptoms. The test results of the Static Steadiness Test, which assesses tremor, were not associated with exposure to mercury vapor. However current smokers had more hand tremor than non-smokers. Statistically significant associations were found between indices of current exposure (the concentration of inorganic mercury in whole blood) and the results of the WAIS Digit Symbol Test and the Benton Visual Retention Test (number of correct responses). This could indicate a small effect of current exposure on visuomotor/psychomotor speed and attention, and immediate visual memory. Whether the association found between the historical exposure intensity and the Digit Symbol Test results may represent long-term consequences of exposure cannot be determined in this study.
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Affiliation(s)
- D G Ellingsen
- National Institute of Occupational Health, Oslo, Norway.
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28
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Ben-Ozer EY, Rosenspire AJ, McCabe MJ, Worth RG, Kindzelskii AL, Warra NS, Petty HR. Mercuric chloride damages cellular DNA by a non-apoptotic mechanism. Mutat Res 2000; 470:19-27. [PMID: 10986472 DOI: 10.1016/s1383-5718(00)00083-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mercury is a xenobiotic metal that is well known to adversely affect the immune system, however, little is known as to the molecular mechanism. Recently, it has been suggested that mercury may induce immune dysfunction by triggering apoptosis in immune cells. Here, we studied the effects of Hg(2+) (HgCl(2)) on U-937 cells, a human cell line with monocytic characteristics. We found that these cells continued to proliferate when exposed to low doses of mercury between 1 and 5 microM. Using the single cell gel electrophoresis (SCGE) or 'comet' assay, we found that mercury damaged DNA at these levels. Between 1 and 50 microM Hg(2+), comet formation was concentration-dependent with the greatest number of comets formed at 5 microM mercury. However, the appearance of mercury-induced comets was qualitatively different from those of control cells treated with anti-fas antibody, suggesting that although mercury might damage DNA, apoptosis was not involved. This was confirmed by the finding that cells treated with 5 microM mercury were negative for annexin-V binding, an independent assay for apoptosis. These data support the notion that DNA damage in surviving cells is a more sensitive indicator of environmental insult than is apoptosis, and suggests that low-concentrations of ionic mercury may be mutagenic.
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Affiliation(s)
- E Y Ben-Ozer
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
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