1
|
O'Donoghue JL, Watson GE, Brewer R, Zareba G, Eto K, Takahashi H, Marumoto M, Love T, Harrington D, Myers GJ. Neuropathology associated with exposure to different concentrations and species of mercury: A review of autopsy cases and the literature. Neurotoxicology 2020; 78:88-98. [PMID: 32092311 DOI: 10.1016/j.neuro.2020.02.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 02/16/2020] [Accepted: 02/21/2020] [Indexed: 11/20/2022]
Abstract
BACKGROUND Human exposure to mercury (Hg) is widespread and both organic and inorganic Hg are routinely found in the human brain. Millions of people are exposed to methyl Hg (MeHg) due to the consumption of fish and to inorganic Hg from dental amalgams, small scale gold mining operations, use of Hg containing products, or their occupations. Neuropathology information associated with exposures to different species of Hg is primarily based on case reports of single individuals or collections of case studies involving a single species of Hg at toxic exposure levels such as occurred in Japan and Iraq. METHODS/RESULTS This study brings together information on the neuropathological findings and deposition of Hg in the central nervous system of people exposed to different species of Hg at varying concentrations. The low dose exposures were lifetime exposures while the high dose exposures were generally acute or short term by different exposure routes with survival lasting various lengths of time. Total and inorganic Hg deposits were identified in formalin-fixed, paraffin embedded tissues from both low and high exposure Hg cases. Low concentration exposures were studied in adult brains from Rochester, New York (n = 4) and the Republic of Seychelles (n = 17). Rochester specimens had mean total Hg concentrations of 16-18 ppb in the calcarine, rolandic, and cerebellar cortices. Inorganic Hg averaged between 5-6 ppb or 30-37% for the cerebral and cerebellar cortices of the Rochester subjects. Total Hg was approximately 10-fold higher in specimens from Seychelles, where consumption of ocean fish is high and consequently results in exposure to MeHg. The predominant Hg species was MeHg in both the Rochester and Seychelles brain specimens. Histologically, cerebral and cerebellar cortices from Rochester and Seychelles specimens were indistinguishable. High concentration exposures were studied in brains from four adults who were autopsied at variable time periods after exposure to organic Hg (methyl or dimethyl) or inorganic Hg (inhaled vapor or intravenous injection of metallic Hg). In contrast to the Seychellois adults, these individuals had acute or subacute exposures to lethal or significantly higher concentrations. The pattern of Hg deposition differed between subjects with high organic Hg exposure and high inorganic Hg exposure. In the organic Hg cases, glia (astrocytes and microglia) and endothelial cells accumulated more Hg than neurons and there were minimal Hg deposits in cerebellar granule and Purkinje cells, anterior horn motor neurons, and neocortical pyramidal neurons. In the inorganic Hg cases, Hg was seen predominantly in neurons, vascular walls, brainstem, and cerebellar and cerebral deep gray nuclei. The presence of inorganic Hg in neural and neural supporting cells in the four high exposure Hg cases was not closely correlated with cellular pathology; particularly in the inorganic Hg cases. CONCLUSIONS Different Hg species are associated with differing neuropathological patterns. No neuropathological abnormalities were present in the brains of either Rochester or Seychelles residents despite substantial differences in dietary MeHg exposure. Increasing concentrations of inorganic Hg were present in the brain of relatively low exposure subjects with increasing age.
Collapse
Affiliation(s)
- John L O'Donoghue
- Department of Environmental Medicine, University of Rochester Medical Center, School of Medicine and Dentistry, Box EHSC, 601 Elmwood Ave, Rochester, NY 14642, United States.
| | - Gene E Watson
- Department of Environmental Medicine, University of Rochester Medical Center, School of Medicine and Dentistry, Box EHSC, 601 Elmwood Ave, Rochester, NY 14642, United States; Eastman Institute for Oral Health and Department of Pharmacology and Physiology, University of Rochester Medical Center, School of Medicine and Dentistry, Box 683, 601 Elmwood Ave, Rochester, NY, 14642, United States
| | - Rubell Brewer
- Victoria Hospital and the Ministry of Health, Seychelles
| | - Grazyna Zareba
- Department of Environmental Medicine, University of Rochester Medical Center, School of Medicine and Dentistry, Box EHSC, 601 Elmwood Ave, Rochester, NY 14642, United States
| | - Komyo Eto
- Formerly Director General, National Institute for Minamata Disease, Ministry of the Environment, 4058-18, Hama, Minamata City, Kumamoto Prefecture, 867-0008, Japan
| | - Hitoshi Takahashi
- Department of Pathology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata, 951-8585, Japan
| | - Masumi Marumoto
- Toxicologic Pathology Section, Department of Basic Medical Sciences, National Institute for Minamata Disease, Ministry of the Environment, 4058-18, Hama, Minamata City, Kumamoto Prefecture, 867-0008, Japan
| | - Tanzy Love
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, School of Medicine and Dentistry, Box 630, 601 Elmwood Ave, Rochester, NY, 14642, United States
| | - Donald Harrington
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, School of Medicine and Dentistry, Box 630, 601 Elmwood Ave, Rochester, NY, 14642, United States
| | - Gary J Myers
- Department of Environmental Medicine, University of Rochester Medical Center, School of Medicine and Dentistry, Box EHSC, 601 Elmwood Ave, Rochester, NY 14642, United States; Department of Neurology, Child Neurology, University of Rochester Medical Center, School of Medicine and Dentistry, Box 631, 601 Elmwood Avenue, Rochester, NY 14642, United States; Department of Pediatrics, University of Rochester Medical Center, School of Medicine and Dentistry, Box 631, 601 Elmwood Ave, Rochester, NY, 14642, United States
| |
Collapse
|
2
|
Ratcliffe HE, Swanson GM, Fischer LJ. Human Exposure to Mercury: A Critical Assessment of the Evidence of Adverse Health Effects. ACTA ACUST UNITED AC 2015. [DOI: 10.1080/00984108.1996.11667600] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
3
|
Lucchini RG, Hashim D. Tremor secondary to neurotoxic exposure: mercury, lead, solvents, pesticides. HANDBOOK OF CLINICAL NEUROLOGY 2015; 131:241-249. [PMID: 26563793 DOI: 10.1016/b978-0-444-62627-1.00014-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Lead, mercury, solvents, and pesticide exposures are common in certain occupations and may cause nervous system dysfunction. Tremors may be the herald manifestation among a constellation of acute toxicity signs and symptoms. However, since tremors may also be the only sign on clinical presentation and since tremors also occur in other diseases, relating tremors to a specific occupational exposure can be challenging. Diagnosis of tremor etiology must be based on other findings on physical exam, laboratory results, and/or imaging. Discerning whether the tremor resulted from the occupational environment versus other etiologies requires knowledge of potential exposure sources, additional detail in history taking, and support of other health and industrial professionals. Reduction or removal from the exposure source remains the key first step in treating patients suffering from tremor that had resulted from occupational exposure toxicity.
Collapse
Affiliation(s)
- Roberto G Lucchini
- Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Unit of Occupational Medicine, Department of Medical Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy.
| | - Dana Hashim
- Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| |
Collapse
|
4
|
Schiønning JD. Experimental neurotoxicity of mercury Autometallographic and stereologic studies on rat dorsal root ganglion and spinal cord. APMIS 2011. [DOI: 10.1111/j.1600-0463.2000.tb05696.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
5
|
Abstract
This review covers the toxicology of mercury and its compounds. Special attention is paid to those forms of mercury of current public health concern. Human exposure to the vapor of metallic mercury dates back to antiquity but continues today in occupational settings and from dental amalgam. Health risks from methylmercury in edible tissues of fish have been the subject of several large epidemiological investigations and continue to be the subject of intense debate. Ethylmercury in the form of a preservative, thimerosal, added to certain vaccines, is the most recent form of mercury that has become a public health concern. The review leads to general discussion of evolutionary aspects of mercury, protective and toxic mechanisms, and ends on a note that mercury is still an "element of mystery."
Collapse
Affiliation(s)
- Thomas W Clarkson
- Department of Environmental Medicine, University of Rochester School of Medicine, New York, USA.
| | | |
Collapse
|
6
|
Obi E, Akunyili DN, Ekpo B, Orisakwe OE. Heavy metal hazards of Nigerian herbal remedies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2006; 369:35-41. [PMID: 16759683 DOI: 10.1016/j.scitotenv.2006.04.024] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 04/10/2006] [Accepted: 04/10/2006] [Indexed: 05/10/2023]
Abstract
The uses of herbal products are not regulated in Nigeria and in many low-income countries and are freely available to everyone. The safety of these herbal medicines is poorly understood. This study characterizes the content of cadmium, copper, iron, nickel, selenium, zinc, lead and mercury in a random sample of Nigerian traditional products. Ready-to-use herbal products were purchased from the open market and digested using HNO3.The heavy metal content of the digested filtrate was determined by atomic absorption spectrometry Uni-cam Model 929. The result showed that 100% of the samples contained elevated amounts of heavy metals. These data alert us to the possibility of heavy metal toxicity from herbal products in Nigeria. The public health hazards from ingestion of herbal medicines should be identified and disclosed by in-depth risk assessment studies.
Collapse
Affiliation(s)
- E Obi
- Toxicology Unit, Department of Pharmacology, College of Health Sciences, Nnamdi Azikiwe University, Nnewi, Nigeria
| | | | | | | |
Collapse
|
7
|
Falnoga I, Tusek-Znidaric M, Stegnar P. The Influence of Long-term Mercury Exposure on Selenium Availability in Tissues: An Evaluation of Data. Biometals 2006; 19:283-94. [PMID: 16799866 DOI: 10.1007/s10534-005-8642-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Accepted: 06/10/2005] [Indexed: 10/24/2022]
Abstract
The precise mechanisms of mercury accumulation and retention are still unclear. Generally, the association of mercury with selenium is used to explain these phenomena. It seems that the presence of coaccumulated endogenous Se can protect cells from the harmful effects of Hg. However, as speculated by some authors, this binding of Se to Hg can also result in a relative deficiency of biologically available Se needed for selenoenzyme syntheses. Deriving from the assumption that Hg deposited in tissues is bound to Se in a 1:1 ratio, the quantity of non-Hg bound Se could be calculated by the difference between the molar contents of the two elements (Se(mol)-Hg(mol)). In this study we applied such an approach to the data from our previous investigation, where Hg and Se concentrations were determined in autopsy samples of mercury exposed retired Idrija mercury mine workers, Idrija residents living in a Hg contaminated environment and a control group with no known Hg exposure from the environment. Based on these data we tried to estimate the influence of Hg exposure on the physiologically available selenium content in selected tissues, particularly endocrine glands and brain tissues. Comparing the calculated values of (Se(mol)- Hg(mol)) it was found that for Idrija residents the values were similar to those of the control group and as expected, diminished values were found in some mercury-loaded organs of retired Idrija miners. It could be speculated that in Idrija residents Hg sequestration of selenium is sufficiently compensated by increased Se levels, but that particularly in active miners and in some organs of retired miners, the activity and/or synthesis of selenoenzymes could be disturbed.
Collapse
Affiliation(s)
- Ingrid Falnoga
- Department of Environmental Sciences, Jozef Stefan Institute, Jamova 39, Ljubljana 1111, Slovenia.
| | | | | |
Collapse
|
8
|
Risher JF, Murray HE, Prince GR. Organic mercury compounds: human exposure and its relevance to public health. Toxicol Ind Health 2002; 18:109-60. [PMID: 12974562 DOI: 10.1191/0748233702th138oa] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Humans may be exposed to organic forms of mercury by either inhalation, oral, or dermal routes, and the effects of such exposure depend upon both the type of mercury to which exposed and the magnitude of the exposure. In general, the effects of exposure to organic mercury are primarily neurologic, while a host of other organ systems may also be involved, including gastrointestinal, respiratory, hepatic, immune, dermal, and renal. While the primary source of exposure to organic mercury for most populations is the consumption of methylmercury-contaminated fish and shellfish, there are a number of other organomercurials to which humans might be exposed. The antibacterial and antifungal properties of organomercurials have resulted in their long use as topical disinfectants (thimerosal and merbromin) and preservatives in medical preparations (thimerosal) and grain products (both methyl and ethyl mercurials). Phenylmercury has been used in the past in paints, and dialkyl mercurials are still used in some industrial processes and in the calibration of certain analytical laboratory equipment. The effects of exposure to different organic mercurials by different routes of exposure are summarized in this article.
Collapse
Affiliation(s)
- John F Risher
- Agency for Toxic Substances and Disease Registry, Division of Toxicology, Toxicology Information Branch, Clifton Road, Atlanta, Georgia 30333, USA
| | | | | |
Collapse
|
9
|
Garvey GJ, Hahn G, Lee RV, Harbison RD. Heavy metal hazards of Asian traditional remedies. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2001; 11:63-71. [PMID: 11260788 DOI: 10.1080/09603120020019656] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In recent years there has been an increase in the use of traditional Asian medicines. It is estimated that 30% of the US population is currently using some form of homeopathic or alternative therapy at a total cost of over $13 billion annually. Herbal medications are claimed and widely believed to be beneficial; however, there have been reports of acute and chronic intoxications resulting from their use. This study characterizes a random sampling of Asian medicines as to the content of arsenic, mercury, and lead. Traditional herbal remedies were purchased in the USA, Vietnam, and China. The Asian remedies evaluated contained levels of arsenic, lead, and mercury that ranged from toxic (49%) to those exceeding public health guidelines for prevention of illness (74%) when consumed according to the directions given in or on the package. Heavy metals contained in Asian remedies may cause illness of unknown origin and result in the consumption of health care resources that are attributable to other causes. The public health hazards of traditional herbal Asian remedies should be identified and disclosed.
Collapse
Affiliation(s)
- G J Garvey
- College of Public Health, University of South Florida, Tampa, Florida, USA
| | | | | | | |
Collapse
|
10
|
Palmer RB, Godwin DA, McKinney PE. Transdermal kinetics of a mercurous chloride beauty cream: an in vitro human skin analysis. JOURNAL OF TOXICOLOGY. CLINICAL TOXICOLOGY 2001; 38:701-7. [PMID: 11192457 DOI: 10.1081/clt-100102383] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Crema de Belleza-Manning is a popular mercurous chloride-containing beauty cream used to smooth and lighten the complexion and treat acne. Hundreds of people in the Southwestern US border states have been identified with elevated (>20 microg/L) urine mercury levels believed to be secondary to using this cream. The kinetic characteristics of percutaneous mercury absorption are incompletely defined. The objective of this study was to determine the transdermal kinetics of two formulations of mercurous chloride from a beauty cream in an in vitro human skin model. METHODS A proprietary formulation and an aqueous formulation of the beauty cream were studied using modified Franz diffusion cells. Mercury content in the skin samples and the underlying diffusion buffer was determined using atomic absorption spectrophotometry. RESULTS A rapid initial increase in mercury content both in the skin and the buffer was noted for both formulations. Mercury concentrations in the aqueous samples were significantly (p < 0.05) higher in both the skin and the diffusion buffer compared to parallel samples containing glycerol. CONCLUSIONS Mercury was readily absorbed through the skin in this in vitro human skin model. The aqueous preparation had a markedly increased rate and extent of mercury absorption relative to the proprietary formulation.
Collapse
Affiliation(s)
- R B Palmer
- Department of Pathology, School of Medicine, University of New Mexico, Albuquerque, USA.
| | | | | |
Collapse
|
11
|
Abstract
The chemical stability in the brain underlies normal human thinking, learning, and behavior. Compelling evidence demonstrates a definite capacity of the choroid plexus in sequestering toxic heavy metal and metalloid ions. As the integrity of blood-brain and blood-CSF barriers, both structurally and functionally, is essential to brain chemical stability, the role of the choroid plexus in metal-induced neurotoxicities has become an important, yet under-investigated research area in neurotoxicology. Metals acting on the choroid plexus can be categorized into three major groups. A general choroid plexus toxicant can directly damage the choroid plexus structure such as mercury and cadmium. A selective choroid plexus toxicant may impair specific plexus regulatory pathways that are critical to brain development and function, rather than induce massive pathological alteration. The typical examples in this category include lead-induced alteration in transthyretin production and secretion as well as manganese interaction with iron in the choroid plexus. Furthermore, a sequestered choroid plexus toxicant, such as iron, silver, or gold, may be sequestered by the choroid plexus as an essential CNS defense mechanism. Our current knowledge on the toxicological aspect of choroid plexus research is still incomplete. Thus, the future research needs have been suggested to focus on the role of choroid plexus in early CNS development as affected by metal sequestration in this tissue, to explore how metal accumulation alters the capacity of the choroid plexus in regulation of certain essential elements involved in the etiology of neurodegenerative diseases, and to better understand the blood-CSF barrier as a defense mechanism in overall CNS function.
Collapse
Affiliation(s)
- W Zheng
- Division of Environmental Health Sciences, School of Public Health, and Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
| |
Collapse
|
12
|
Warfvinge K. Mercury distribution in the neonatal and adult cerebellum after mercury vapor exposure of pregnant squirrel monkeys. ENVIRONMENTAL RESEARCH 2000; 83:93-101. [PMID: 10856181 DOI: 10.1006/enrs.1999.4013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The objectives of the study were (1) to map the detailed localization of mercury in the monkey cerebellum after mercury vapour exposure; (2) to investigate whether there is any difference in mercury distribution between neonatal and adult cerebellum after mercury vapor exposure; (3) to investigate the ability of mercury to accumulate in the cerebellum years after the end of exposure. Pregnant squirrel monkeys were exposed 5 days/week to mercury vapor at a concentration of 0.5 mg Hg/m(3) air 4 or 7 h/day or 1 mg Hg/m(3) air for 4 or 7 h/day. Mercury concentration in the offspring and maternal brains was examined by cold vapor, flameless atomic absorption spectrophotometry. Mercury distribution was examined by processing cerebellar sections for autometallographic (AMG) silver enhancement. Mercury concentration in the offspring cerebral occipital pole ranged between 0.20 and 0.70 microg Hg/g tissue, and in the maternal between 0.80 and 2.58 microg/Hg tissue in animals killed immediately after the end of exposure. AMG revealed that the external granule cell layer of offspring cerebellar tissue contained small amounts of mercury. The molecular layer contained mercury in some of the mercury-exposed monkeys. In the Purkinje cell layer, the Bergmann glial cells together with the Purkinje cells contained mercury. The granule cells and the Golgi cells contained small amounts of mercury. The astrocytes of the medullary layer, identified by immunohistochemistry, contained considerable amounts of mercury, but the cerebellar nuclei accumulated the highest amounts of mercury. No correlation was found between cellular accumulation and maturity of the brain; that is, the cellular localization of mercury did not differ between adult and neonatal brain, except for the amount of visualized mercury. This pattern corresponded well to the mercury concentrations found in the cerebral occipital pole. The differences found in mercury accumulation were instead considered to be dose-related. The results demonstrate that the distribution of mercury in the cerebellum after mercury vapor exposure is similar to the distribution pattern obtained after methyl mercury exposure and that mercury is trapped in the cerebellum over a long period of time.
Collapse
Affiliation(s)
- K Warfvinge
- Department of Ophthalmology, University Hospital of Lund, Lund, S-221 85, Sweden.
| |
Collapse
|
13
|
Schoof RA, Nielsen JB. Evaluation of methods for assessing the oral bioavailability of inorganic mercury in soil. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 1997; 17:545-555. [PMID: 9404045 DOI: 10.1111/j.1539-6924.1997.tb00896.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The risks associated with environmental exposures to inorganic mercury are typically assessed based on toxicity studies conducted with the soluble salt, mercuric chloride (HgCl2). Evidence indicates, however, that inorganic mercury is present in soil as a variety of compounds and that oral absorption of inorganic mercury decreases with a decrease in the solubility of the mercury compound being studied. Thus, while HgCl2 is approximately 15-20% bioavailable, the bioavailability of cinnabar (HgS) may be 30- to 60-fold less. The solubility and, hence, bioavailability of inorganic mercury in soil is expected to be substantially less than that of HgCl2 due to the presence of less soluble compounds and their interactions with soil constituents. Quantification of this difference in bioavailability is important in assessing potential risks associated with exposure to mercury-containing soil. A review of available studies supports the expectation that mercury bioavailability in soils will be reduced. This paper reviews methods for assessing soil metal absorption with consideration of the characteristics of the oral absorption of elemental and inorganic mercury that should be evaluated in designing additional studies. Because of the very slow elimination of mercury in some species, it is recommended that a repeated-dose study be conducted. Such a study would yield an estimate of relative bioavailability based on a comparison of tissue mercury concentrations in animals ingesting soil with those of animals receiving HgCl2. The dose, age, gender, and species of animal selected are not expected to affect relative bioavailability estimates; however, it is recommended that studies be conducted in two animal species. Rats should be used because they have been used in many studies of mercury absorption and toxicity. A species of large animals such as monkeys, swine, or dogs should also be used to provide confirmation in a species with greater similarities to humans in gastrointestinal physiology and anatomy. Other critical factors in designing these studies, such as selection and characterization of soil samples, are also addressed.
Collapse
Affiliation(s)
- R A Schoof
- PTI Environmental Services, Bellevue, Washington 98007, USA
| | | |
Collapse
|
14
|
Affiliation(s)
- R Von Burg
- ICF Kaiser Engineers, Oakland, CA 94612, USA
| |
Collapse
|
15
|
Abstract
The aim of this review is to point out the health hazards of the uncontrolled global use of implanted mercury-leaking dental amalgam fillings. In spite of the pandemic use of amalgam, most dentists and doctors are still ignorant about the levels of mercury exposure and its health implications. This review discusses the following chronically neglected aspects in clinical practice: The use of materials science in calculating the mercury exposure levels, which may exceed the TLVs by an order of magnitude; Microbial dissolution and methylation of mercury from amalgam by oral and intestinal bacteria; Diagnostic problems and effects of chronic mercury exposure with emphasis on intestinal, cardiovascular, mental and neurologic symptoms and disorders; Diagnostic value of faeces--instead of urine examination--as the main indicator of Hg exposure; Lack of control groups unexposed to Hg (amalgam free) for epidemiologic investigations of health problems; Contribution of dental mercury to environmental pollution. In conclusion, a lack of interdisciplinary research and of a critical approach to established clinical routine appears to be the reason for the failure of the dental profession to protect the patient from Hg exposure when saving the tooth.
Collapse
Affiliation(s)
- J Pleva
- Uddeholm Tooling AB, Research & Development, Hagfors, Sweden
| |
Collapse
|
16
|
Hargreaves RJ, Evans JG, Janota I, Magos L, Cavanagh JB. Persistent mercury in nerve cells 16 years after metallic mercury poisoning. Neuropathol Appl Neurobiol 1988; 14:443-52. [PMID: 3226504 DOI: 10.1111/j.1365-2990.1988.tb01336.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A male subject, after exposure to mercury metal at work in 1968, developed classical signs of mercurialism from which he made a slow clinical recovery. He subsequently developed psychoneurotic symptoms and became an alcoholic; he never returned to work and died in 1984. No histological changes relevant to mercury intoxication were found in the brain, but staining by Danscher & Schroeder's method for mercury showed many positively staining lysosomal dense bodies in a large proportion of nerve cells, and the presence of mercury was confirmed by elemental X-ray analysis. The mercury content of the brain was increased, much of it being present in colloidal form.
Collapse
|
17
|
Zampollo A, Baruffini A, Cirla AM, Pisati G, Zedda S. Subclinical inorganic mercury neuropathy: neurophysiological investigations in 17 occupationally exposed subjects. ITALIAN JOURNAL OF NEUROLOGICAL SCIENCES 1987; 8:249-54. [PMID: 3623876 DOI: 10.1007/bf02337482] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
17 workers in a thermometer factory exposed to mercury for periods ranging from 1 to 40 years all had high urine and blood mercury levels on undergoing electromyographic examination. All were clinically free from central and peripheral nervous symptoms. 88% had subclinical neuropathy, mainly distal and axonal. There was no correlation between severity of the neuropathy and blood and urine mercury levels or between severity of neuropathy and duration of exposure to mercury. The presence of a subclinical neuropathy in symptomless workers exposed to mercury is perhaps the most reliable index for the detection of the early toxic effects of mercury on the peripheral nerve fiber when it is probably still reversible.
Collapse
|
18
|
Abstract
A male patient was admitted to hospital 12 h after self-poisoning with mercuric chloride. He suffered multiple complications including acute renal failure, ulcerative colitis, anaemia, disseminated intravascular coagulation, chronic sepsis and severe weight loss. Initially he responded well to resuscitative measures and intensive supportive therapy, which included ventilation of the lungs, haemodialysis, dimercaprol, antibiotics, parenteral feeding and gastrointestinal surgery. Unfortunately the sepsis was never satisfactorily eradicated despite satisfactory serum concentrations of the appropriate antibiotics. On day 43 after poisoning he had a grand mal fit; after this there were focal neurological signs and on lumbar puncture he was found to have a raised protein concentration and raised pressure in his cerebrospinal fluid. The condition of the patient rapidly deteriorated and on day 47 he died. Post-mortem examination revealed a large cerebellar abscess. The literature on mercury poisoning is reviewed.
Collapse
|
19
|
Gerstner HB, Huff JE. Clinical toxicology of mercury. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1977; 2:491-526. [PMID: 321797 DOI: 10.1080/15287397709529452] [Citation(s) in RCA: 81] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Based on an extensive literature search, general principles of mercury toxicity are outlined with respect to human individuals and populations. For the metal itself, as well as for its most important inorganic and organic compounds, the review discussed behavior in the body, characteristic clinical pictures, assessment of threshold levels, and evaluation as potential environmental hazards. Particular emphasis is placed on those diagnostic signs and symptoms which furnish early warning signals, permitting detection and elimination of overexposures.
Collapse
|
20
|
JACOBS JEANM, CAVANAGH JB, CARMICHAEL N. THE EFFECT OF CHRONIC DOSING WITH MERCURIC CHLORIDE ON DORSAL ROOT AND TRIGEMINAL GANGLIA OF RATS. Neuropathol Appl Neurobiol 1975. [DOI: 10.1111/j.1365-2990.1975.tb00656.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|