Some articles in the mercury- / amalgam- / health-field from 1996 (Abstracts)

Subjective selection by Leif Hedegard. Updated 12 July 1997.

Albright JF & Goldstein RA Airborne pollutants and the immune system. Otolaryngology & Head & Neck Surgery 114(2):232-238 (1996)
ABSTRACT: "The effects of airborne pollutants on the immune system have been most widely studied in the respiratory tract, Entry may occur as a volatile gas (ozone, benzene), as liquid droplets (sulfuric acid, nitrogen dioxide), or as particulate matter (diesel exhaust, aromatic hydrocarbons), The subsequent interaction with the immune system may result in local and systemic responses, and studies have shown examples of disease occurring from both overactive immune responses and immunosuppression. For the most part, airborne pollutants (small molecular weight chemicals) have to be coupled with other substances (proteins or conjugates) before they can be recognized by the immune system and exert their effects. Fortunately, this encounter rarely causes immunologically mediated human disorders, The following briefly reviews some of the disorders that may occur, Immunologically nonspecific inflammation of the lung can occur after inhalation of ozone in anyone given sufficient dose and time of exposure, Immunologically specific cell-mediated (T lymphocyte) reactions appear to predominate in chronic beryllium disease, which results in a granulomatous form of lung disease, Beryllium alone does not appear to be antigenic but requires chemical linkage with a larger molecule, Mercury-induced autoimmune disease (immune system attacks self-antigens) affecting kidneys and lungs has been demonstrated in animal models (changes similar to those seen in people with Goodpasture's syndrome), Immunosuppression can be demonstrated after exposure to polycyclic aromatic hydrocarbons (2,3,7,8-tetrachlorodibenzo-p-dioxin). Hypersensitivity (or allergic) reactions can occur after exposure to toluene diisocyanate (occupational asthma). In summary, airborne pollutants may cause a wide spectrum of immunologically mediated disorders, There is clearly an underlying genetic basis for the susceptibility to immunologic disease resulting from exposure to pollutants, but knowledge in this area is rudimentary at present. Studies have been impeded by lack of appropriate in vitro models, as well as difficulties in identifying the biologically active substance."

Bjorkman L, Pedersen NL & Lichtenstein P. Physical and mental health related to dental amalgam fillings in Swedish twins. Comm Dent Oral Epidem 24(4):260-267 (1996)
ABSTRACT: "In the past years increasing attention has been paid to possible adverse health effects of mercury exposure from dental amalgam filling. To evaluate possible health effects from amalgam fillings, dental status registered by specially trained nurses was obtained from 587 subjects included in the ongoing Swedish Adoption/Twin Study of Aging (SATSA). Data on physical and mental health were collected and memory function tested. Mean age was 65 years (SD 9, range 46-89). In the entire material, 25% of the individuals had no own teeth and in the group with own teeth the median number of teeth surfaces filled with dental amalgam was 15 (range 0-65). Analyses of associations between number of surfaces filled with dental amalgam and a number of scales estimating somatic and mental health and memory functions were performed both for the entire group and for individuals having at least 12 teeth. Regardless of the sample, no negative effects on physical or mental health were found from amount of dental amalgam, even after controlling for age, gender, education and number of remaining teeth. When using a co-twin control design with twin pairs discordant for amalgam exposure, no negative health effects associated with dental amalgam were detected. This study does not indicate any negative effects from dental amalgam on physical or mental health or memory functions in the general population over 50 years of age."

Fredriksson A, Dencker L, Archer T & Danielsson BGR. Prenatal Coexposure to Metallic Mercury Vapour and Methylmercury Produce Interactive Behavioural Changes in Adult Rats. Neurotoxicol Teratol 19(2):129-134 (1996)
ABSTRACT: "Pregnant rats were 1) administered methyl mercury (MeHg) by gavage, 2 mg/kg/day during day 6-9 of gestation, 2) exposed by inhalation to metallic mercury (Hg0) vapour (1.8 mg/m3 air for 1.5 h per day) during gestation days 14-19, 3) exposed to both MeHg by gavage and Hg0 vapour by inhalation (MeHg + Hg0), or 4) were given combined vehicle administration for each of the two treatments (control). The inhalation regimen corresponded to an approximate dose of 0.1 mh Hg0/kg/day. Clinical observations and developmental markers up to weaning showed no differences between any of the groups. Testing of behavioural function was performed between 4 and 5 months of age and included spontaneous motor activity, spatial learning in a circular bath, and instrumental maze learning for food reward. Offspring of dams exposed to Hg0 showed hyperactivity in the motor activity test chambers over all three parameters: locomotion, rearing and total activity; this effect was potentiated in the animals of the MeHg + Hg0 group. In the swim maze test, the MeHg + Hg0 and Hg0 groups evidenced longer latencies to reach a submerged platform, which they had learned to mount the day before, compared to either the control or MeHg groups. In the modified, enclosed radial arm maze, both MeHg + Hg0 and Hg0 groups showed more ambulations and rearings in the activity test prior to the learning test. During the learning trial, the same groups (i.e., MeHg + Hg0 and Hg0) showed longer latencies and made more errors in acquiring all eight pellets. Generally, the results indicate that prenatal exposure to Hg0 causes alterations to both spontaneous and learned behaviours, suggesting some deficit in adaptive functions. Coexposure to MeHg, which by itself did not alter these functions at the dose given in this study, served to significantly aggravate the changes."

Henningsson M & Sundbom E. Defensive characteristics in individuals with amalgam illness as measured by the percept-genetic method Defence Mechanism Test. Acta Odont Scand 54(3):176-181 (1996)
ABSTRACT: "Twenty patients complaining of symptoms deriving from their amalgam fillings and a non-patient group were assessed by means of the perceptual projective Defense Mechanism Test (DMT). The test protocols were scored for 130 DMT variables and analyzed by means of the multivariate statistical method Partial Least Squares discriminant analysis. The objective was to try to distinguish the group with amalgam illness from the non-patient group by means of the DMT. The results showed that. it was possible to distinguish the two groups significantly from each other. The most characteristic traits of the patient group were a general lateness in perception and few emotional responses compared with the non-patient group and, especially, an inability to perceive the aggressive component in the stimulus picture. The DMT seems to be a powerful method in the effort to understand the mechanisms underlying the problems of amalgam illness."

Mullerminy H, Erber D, Moller H, Mullerminy B & Bongartz G. Is there a hazard to health by mercury exposure from amalgam due to MRI. J Magnetic Resonance Imaging 6(1):258-260 (1996)
ABSTRACT: "The local magnetic fields from computer monitors are well known. Recently a hypothesis was published that these magnetic fields may lead to a 400% increase of mercury dissolution from dental amalgam fillings. In MRI:the exposure to the magnetic field exceeds by far the exposure from computer monitors. Therefore, this study examined the amalgam-related mercury release for typical MRI conditions, separated for both the static and the variable magnetic fields in a 1.5 T MR-unit, First, 20 dental cavities were filled with a non-gamma-2 amalgam, and the mercury release was measured for 14 days in a non-magnetic environment. Second,one half of the specimens were exposed to a static magnetic field for 24 hours (group A), while the other specimens were exposed to a repetitive gradient echo sequence for 60 minutes (group B), In both experiments there was no significant increase in mercury release due to MRI. This in vitro study demonstrated no evidence of an elevated mercury dissolution from a non-gamma-2 amalgam during magnetic field exposure by MRI; therefore, there is no increased risk to health."

Nadarajah V, Neiders ME, Aguirre A & Cohen RE. Localized cellular inflammatory responses to subcutaneously implanted dental mercury. J Toxicol & Environ Health 49(2):113-125 (1996)
ABSTRACT: "Previous reports have demonstrated mercury accumulation and toxicity in oral tissues following exposure to mercury vapor from dental amalgam restorations. In the present study, inflammatory responses to subcutaneously administered mercury were assessed histopathologically and immunocytochemically in a rat model system. A panel of six well-characterized monoclonal antibodies specific for monocytes, macrophage subsets, T and B lymphocytes, and major histocompatibility complex (MHC) class II (la) determinants was used to quantitate alterations in mononuclear cell subsets in situ at time intervals from 2 d to 8 wk. The results revealed acute inflammatory cell infiltration at 2 and 3 d, followed by chronic inflammation that persisted after 8 wk. The numbers of monocytes, resident macrophage subsets, and mononuclear cells expressing la antigen were significantly different from control tissues at 1-2 wk. The numbers of resident macrophages remained significantly higher even after 8 wk. These data showed that in situ mercury accumulation can lead to altered expression of MHC class II determinants with persistent chronic inflammation and shifts in mononuclear cell subpopulations."

Newland MC, Warfvinge K & Berlin M. Behavioral consequences of in utero exposure to mercury vapor: alterations in lever-press durations and learning in squirrel monkeys. Toxicol & Appl Pharm 139(2):374-386 (1996)
ABSTRACT: "Exposure to mercury vapor in utero results in the accumulation of mercury in the cerebellum, hippocampus, and other regions of the nervous system associated with motor function and learning, but little is known about the functional consequences of prenatal exposure. The offspring of pregnant squirrel monkeys exposed to 0.5 or 1.0 mg/m3 of mercury vapor during the last 2/3 or more of gestation were studied. Median maternal blood levels ranged from 0.025 to 0.18 microgram/g and exposures were estimated to range from 20 to 62 micrograms/day, with cumulative doses of 1304 to 4305 micrograms. Unexposed monkeys born at about the same time served as controls. The monkeys' lever pressing was maintained under various Concurrent Random-Interval Random-Interval schedules of reinforcement. Time allocation on each lever was examined during behavioral transitions and in steady state. No difference in sensitivity to reinforcer ratios was identified in steady state, but there was much more variability in the steady-state performance of exposed monkeys, as indicated by the standard deviation of the regression, than in controls. Logistic regression was used to examine the transition to new schedule parameters. Exposed monkeys were found to produce smaller or slower transitions than controls. The magnitude and stability of lever-press durations for controls and exposed monkeys were indistinguishable early in the experiment, but at the end the exposed monkeys had longer lever-press durations and the session-to-session variability was much greater. One monkey's exposure began during the third week of gestation (earlier than any of the others) and the behavior of this monkey was so erratic that some of the analyses could not be accomplished. Long-term effects of prenatal mercury vapor exposure included instability in lever-press durations and steady-state performance under concurrent schedules of reinforcement as well as aberrant transitions. The levels used were close to those reported in occupational settings under conditions of poor hygiene, but were at least 10- to 50-fold greater than those more commonly reported."

Oskarsson A, Schultz A, Skerfving S, Hallen IP, Ohlin B & Lagerkvist BJ. Total and inorganic mercury in breast milk in relation to fish consumption and amalgam in lactating women. Arch Environ Health 51(3):234-241 (1996)
ABSTRACT: "Total mercury concentrations (mean +/- standard deviation) in breast milk, blood, and hair samples collected 6 wk after delivery from 30 women who lived in the north of Sweden were 0.6 +/- 0.4 ng/g (3.0 +/- 2.0 nmol/kg), 2.3 +/- 1.0 ng/g (11.5 +/- 5.0 nmol/kg), and 0.28 +/- 0.16 microg/g (1.40 +/- 0.80 micromol/kg), respectively. In milk, an average of 51% of total mercury was in the form of inorganic mercury, whereas in blood an average of only 26% was present in the inorganic form. Total and inorganic mercury levels in blood (r = .55, p = .003; and r = .46, p = .01 6; respectively) and milk (r = .47, p = .01; and r = .45, p = .018; respectively) were correlated with the number of amalgam fillings. The concentrations of total mercury and organic mercury (calculated by subtraction of inorganic mercury from total mercury) in blood (r = .59, p = .0006, and r = .56, p = .001; respectively) and total mercury in hair (r = .52, p = .006) were correlated with the estimated recent exposure to methylmercury via intake of fish. There was no significant between the milk levels of mercury in any chemical form and the estimated methylmercury intake. A significant correlation was found between levels of total mercury in blood and in milk (r = .66, p = .0001), with milk levels being an average of 27% of the blood levels. There was an association between inorganic mercury in blood and milk (r = .96, p < .0001); the average level of inorganic mercury in milk was 55% of the level of inorganic mercury in blood. No significant correlations were found between the levels of any form of mercury in milk and the levels of organic mercury in blood. The results indicated that there was an efficient transfer of inorganic mercury from blood to milk and that, in this population, mercury from amalgam fillings was the main source of mercury in milk. Exposure of the infant to mercury from breast milk was calculated to range up to 0.3 microg/kg x d, of which approximately one-half was inorganic mercury. This exposure, however, corresponds to approximately one-half the tolerable daily intake for adults recommended by the World Health Organization. We concluded that efforts should be made to decrease mercury burden in fertile women."

Ostman PO, Anneroth G & Skoglund A. Amalgam-associated oral lichenoid reactions - clinical and histologic changes after removal of amalgam. Oral Surgery Oral Medicine Oral Pathology Oral Radiology & Endodontics 81(4):459-465 (1996)
ABSTRACT: "Objective and study design. Forty-nine consecutive patients with clinically diagnosed oral lichenoid reactions in contact with amalgam fillings were studied clinically and histologically. The long-term effect of replacement of these fillings was also examined. Results. Seventeen (35%) patients showed positive reactions to mercury at the epicutaneous patch test that was carried out before treatment. After treatment, total regression of the lesions was found clinically in 33 (69%) and histologically in 26 (55%) patients. Most of the remaining lesions changed clinically and histologically to a less pronounced tissue reaction. Lesions in direct contact with amalgam fillings (group I) showed significantly better healing results than lesions that exceeded the contact area (group II). No difference in healing capacity was noted in the two groups between patients with positive patch reactions to mercury compared with those with negative reactions. Lesions that histologically were classified as benign oral keratosis showed a similar healing pattern as those classified as oral lichen planus. Conclusion. In group I all lesions changed histologically and clinically to a normal mucosa or to a less affected tissue reaction. In group II this change was less pronounced, which suggests that the fillings themselves were not the only factor involved in the cause of these lesions. The results suggest that various etiologic factors are involved in lichenoid reactions and that the effect of removal of amalgam fillings cannot be predicted by epicutaneous patch testing and biopsies."

Pamphlett R & Waley P. Motor Neuron Uptake of Low Dose Inroganic Mercury. J Neurological Sciences 135:63-67 (1996)
ABSTRACT: "In animals, inorganic mercury can bypass the blood brain barrier and enter motor neurons. We sought to determine the lowest injected dose of mercury that could be detected in mouse motor neurons. Mice were injected intraperitoneally with mercuric chloride in doses from 0.05 to 2 micrograms/g body weight and studied between 5 days and 18 months after injection. After formalin fixation, 7 microns sections of cerebrum, cerebellum, brain stem, spinal cord and kidney were stained with silver nitrate autometallography. Five days after injection, mercury granules were detected at doses from 0.2 microgram/g upwards in the cell bodies of spinal and brain stem motor neurons, more granules being seen at the higher doses. Mercury granules were also seen in 5% of posterior root ganglion neurons. At doses from 0.05 microgram/g upwards mercury was detected 5 days later in renal tubule cells. Mercury was still present in motor neurons 6-11 months after injection, but by this time mercury had been cleared from the kidneys. Low doses of inorganic mercury are therefore selectively taken up and retained by motor neurons, making this neurotoxin a good candidate for a cause of sporadic motor neuron disease."

Seidler A, Hellenbrand W, Robra BP, Vieregge P, Nischan P, Joerg J, Oertel WH, Ulm G & Schneider E. Possible environmental, occupational, and other etiological factors for Parkinsons disease - a case-control study in Germany. Neurology 46(5):1275-1284 (1996)
ABSTRACT: "In a case-control study, we investigated the possible etiologic relevance to Parkinson's disease (PD) of rural factors such as farming activity, pesticide exposures, well-water drinking, and animal contacts; toxicologic exposures such as wood preservatives, heavy metals, and solvents; general anesthesia; head trauma; and differences in the intrauterine environment. We recruited 380 patients in nine German clinics, 379 neighborhood control subjects, and 376 regional control subjects in the largest case-control study investigating such factors and collected data in structured personal interviews using conditional logistic regression to control for educational status and cigarette smoking. The latter was strongly inversely associated with PD. There were significantly elevated odds ratios (OR) for pesticide use, in particular, for organochlorines and alkylated phosphates, but no association was present between PD and other rural factors, A significantly elevated OR was present for exposure to wood preservatives. Subjective assessment by the probands indicated that exposure to some heavy metals, solvents, exhaust fumes, and carbon monoxide was significantly more frequent among patients than control subjects, but this was not confirmed by a parallel assessment of job histories according to a job exposure matrix. Patients had undergone general anesthesia and suffered severe head trauma more often than control subjects, but a dose-response gradient was not present. Patients reported a significantly larger number of amalgam-filled teeth before their illness than control subjects. The frequency of premature births and birth order did not differ between patients and control subjects. Patients reported significantly more relatives affected with PD than control subjects. These results support a role for environmental and genetic factors in the etiology of PD."

Stejskal VDM, Forsbeck M, Cederbrant KE & Asteman O. Mercury-Specific Lymphocytes: An Indication of Mercury Allergy in Man. J Clin Immun 16(1):31-34 (1996)
ABSTRACT: "In this study, 18 patients with oral lichen planus (OLP), adjacent to amalgam fillings, were tested in vitro with an optimized lymphocyte proliferation test, MELISA (memory lymphocyte immunostimulation assay) and with a patch test. Twenty subjects with amalgam fillings but without oral discomfort and 12 amalgam-free subjects served as controls. The results show that patients with OLP have significantly higher lymphocyte reactivity to inorganic mercury, a corrosion product of amalgam, compared to control groups. Removal of amalgam fillings resulted in the disappearance of oral mucosal changes, thus indicating a causal relationship. Positive responses to phenylmercury (phenyl-Hg), a bactericidal agent in root fillings and in pharmaceutical preparations, were also noted in the oral lichen group but not in the control groups. Thus, low-grade chronic exposure to mercury may induce a state of systemic sensitization as verified by Hg-specific lymphocyte reactivity in vitro."

Tahan JE, Barrios LC, Marcano L,Granadillo VA, Cubillan HS, Sanchez JM, Rodriguez MC, Desalazar FG, Salgado O & Romero RA. Levels of Hg, Pb and V in brain, kidney, liver and lung of anencephalic fetuses from the eastern coast of Lake Maracaibo, Venezuela. Trace Elements in Medicine 13(1):7-13 (1996)
ABSTRACT: "This work describes the levels of mercury (Hg), lead (Pb) and vanadium (V) in brain, kidney, liver and lung of anencephalic (A) and control (C) fetuses from the Eastern coast of Lake Maracaibo (Venezuela) evaluated from April 1993 to July 1994. A relatively high anencephaly rate of 5.1 per 1,000 total births was reported in this area for 1994. A petroleum empire has grown indiscriminately in the region under study, provoking adverse effects in the environment and in humans due to the constant release of these toxicants. Sample analyses were done by cold vapour atomic absorption spectrometry (for Hg), differential pulse anodic stripping voltammetry (for Pb) and electrothermal atomization atomic absorption spectrometry (for V). Twenty stillborn fetuses with anencephaly (mean gestation age 34.4 weeks, range 20 - 40 weeks) and 20 stillborn fetuses without anencephaly (mean gestation age 38.5 weeks, range 36 - 40 weeks), included as controls, were considered for the present study. All births occurred at ''Pedro Garcia Clara'' Hospital, a public health care center of Ciudad Ojeda (Lagunilla county). Before the spectrometric and voltammetric determinations, samples were mineralized by microwave heating in high-pressure reactors. For all metals, precision (RSD) was better than 5.3%, for both within- and between-run (day-to-day) analyses, which can be considered adequate for these types of analytical evaluations of real samples. Accuracy was tested by analyzing 4 standard reference materials, supplied by 2 international agencies. The dry weight metal concentrations (mean a 1 SD, mu g/g) found in brain, kidney, liver and lung were as follows: Hg (brain, 0.07 +/- 0.01 in A, undetectable in C; kidney, 0.29 +/- 0.05 in A, 0.07 +/- 0.03 in C; liver, 0.33 +/- 0.03 in A, 0.17 +/- 0.08 in C; lung, 0.45 +/- 0.40 in A, 0.12 +/- 0.01 in C); Pb (brain, undetectable in A and in C; kidney, 1.9 +/- 0.3 in A, 0.7 +/- 0.3 in C; liver, 2.1 +/- 0.3 in A, 1.1 +/- 0.5 in C; lung, 3.3 +/- 0.4 in A, 0.5 +/- 0.1 in C); V (brain, 0.25 +/- 0.18 in A, 0.64 +/- 0.28 in C). Mercury and Pb were significantly increased (p < 0.001) in kidney and liver of anencephalic fetuses. Vanadium was detected exclusively at brain level, being significantly higher in controls (p < 0.05). Hence, V seems to be the most unlikely of the 3 elements studied to be associated with anencephaly. In conclusion, Hg and Pb are toxic elements present in the Eastern coast's environment that should be seriously considered for cause/effect studies when the etiology of anencephaly in this region is considered. However, this malformation is multifactorial and, thus, a more complete study must be carried out in order to be able to reach conclusive ideas, if this is possible. Meanwhile, anencephaly will continue to be a puzzling disease."