Neurotological Studies upon Intoxication by Organic Mercury Compounds

Mizukoshi, Kanemasa; Nagaba, M.; Ohno, Yukiko; Ishikawa, Kazumitsu; Aoyagi, Masaru; Watanabe, Yoshinori; Kato, Isao; H, Ino

doi:10.1159/000275209

Cited by 36 publications

(7 citation statements)

References 5 publications

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“…Chromiutn, cobalt and mercury accumulated in the CNS. The penetration ol mercury through the blood-brain barrier and its specific affinity for certain neural structures has been correlated with many clinical findings (5,22). The tnercuric ions primarily affect certain specific regions of the CNS, such as the choroid plexus, that are devoid of tight junctions between the endothelial cells (4).…”

Section: Discussionmentioning

confidence: 99%

Autoradiographic study of distribution patterns of metals which occur as corrosion products from dental restorations

Söremark

Diab

Arvidson

1979

European J Oral Sciences

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– Radioactive chromium, cobalt, gold and mercury, all of which may occur as corrosion products from dental restorations, were injected in single doses via the tail vein of mice and an in vivo analysis of their distribution was performed using whole‐body autoradiography. Gold seemed to be inert and went mainly to the liver and bones. The other elements studied were distributed widely in the body and remained for a long period of time in specific target organs and tissues.

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Section: Discussionmentioning

confidence: 99%

Autoradiographic study of distribution patterns of metals which occur as corrosion products from dental restorations

Söremark

Diab

Arvidson

1979

European J Oral Sciences

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“…Audiometry and neuropathologic observations suggest a combination of cochlear (hair cell) and retro-cochlear dysfunction (Mizukoshi, Nagaba, 1975). Longitudinal follow-up of these patients has identified subgroups with either chronic hearing loss or with improved hearing which suggests that hair cell loss cannot fully explain the deficits observed (Harada, 1995, Mizukoshi et al, 1989, Uchino et al, 1995).…”

Section: Resultsmentioning

confidence: 99%

“…Methylmercury can be neurotoxic to the developing brain in adequate doses, but the level of exposure where harmful effects begin to occur is presently not known (Clarkson, 1995, Davidson et al, 2006). Fetal neurologic effects seen in the overt poisonings that occurred in Japan and Iraq included severe developmental and intellectual disabilities (Bakir et al, 1973, Mizukoshi et al, 1975). The effects, if any, of lower-dose exposures are less clear.…”

Section: Introductionmentioning

confidence: 99%

Neurophysiologic measures of auditory function in fish consumers: Associations with long chain polyunsaturated fatty acids and methylmercury

Dziorny¹,

Orlando²,

Strain³

et al. 2013

NeuroToxicology

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Background Determining if associations exist between child neurodevelopment and environmental exposures, especially low level or background ones, is challenging and dependent upon being able to measure specific and sensitive endpoints. Psychometric or behavioral measures of CNS function have traditionally been used in such studies, but do have some limitations. Auditory neurophysiologic measures examine different nervous system structures and mechanisms, have fewer limitations, can more easily by quantified, and might be helpful testing additions. To date, their use in human epidemiological studies has been limited. We reviewed the use of auditory brainstem responses (ABR) and otoacoustic emissions (OAE) in studies designed to determine the relationship of exposures to methyl mercury (MeHg) and nutrients from fish consumption with neurological development. We included studies of experimental animals and humans in an effort to better understand the possible benefits and risks of fish consumption. Objectives We reviewed the literature on the use of ABR and OAE to measure associations with environmental exposures that result from consuming a diet high in fish. We focused specifically on long chain polyunsaturated fatty acids (LCPUFA) and MeHg. Methods We performed a comprehensive review of relevant studies using web-based search tools and appropriate search terms. Results Gestational exposure to both LCPUFA and MeHg has been reported to influence the developing auditory system. In experimental studies supplemental LCPUFA is reported to prolong ABR latencies and human studies also suggest an association. Experimental studies of acute and gestational MeHg exposure are reported to prolong ABR latencies and impair hair cell function. In humans, MeHg exposure is reported to prolong ABR latencies, but the impact on hair cell function is unknown. Conclusion The auditory system can provide objective measures and may be useful in studying exposures to nutrients and toxicants and whether they are associated with children’s neurodevelopment.

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“…A few adults with Minamata disease have shown hearing loss or elevated hearing thresholds as a clinical feature of accidental poisoning (McAlpine and Araki, 1958; Kurland et al, 1960; Nosaka et al, 1970; Fujisaki et al, 1971; Mizukoshi et al, 1975; Ino and Mizukoshi, 1977). Prolonged ABR latencies were also reported in patients diagnosed with Minamata disease, although exposure verification was not possible (Hamada et al, 1982, Inayoshi et al, 1993).…”

Section: 0 Introductionmentioning

confidence: 99%

Associations between prenatal and recent postnatal methylmercury exposure and auditory function at age 19years in the Seychelles Child Development Study

Orlando

Dziorny

Harrington

et al. 2014

Neurotoxicology and Teratology

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Objectives To determine if prenatal or recent postnatal methylmercury (MeHg) exposure from consuming ocean fish and seafood is associated with auditory deficits in young adults. Some investigators have reported adverse associations while others have found no associations. Ocean fish is an important nutrient source for billions of people around the world. Consequently, determining if there is an adverse association with objective auditory measures is important in assessing whether a risk is present or not. Design The peripheral and central auditory function of 534 subjects in the Seychelles Child Development Study (SCDS) Main Cohort was examined at age 19 years. The auditory test battery included standard pure-tone audiometry, tympanometry, Auditory Brainstem Response (ABR) latencies, and both click-evoked and distortion-product Otoacoustic Emissions (OAE). Associations with MeHg were evaluated with multiple linear regression models, adjusting for sex, recent postnatal MeHg exposure, and hearing loss. Results Bilateral hearing loss (defined as a mean pure-tone threshold of greater than 25 dB) was present in 1.1% of the subjects and was not associated with prenatal or recent postnatal MeHg exposure. As expected, absolute and interwave ABR latencies were shorter for women as compared to men, as the stimulus presentation rate decreased from 69.9 to 19.9 clicks/sec and as the stimulus intensity increased from 60 to 80 dBnHL. Similarly, larger OAE amplitudes were elicited in women as compared to men and in the right ears as compared to the left. There was no association of prenatal MeHg exposure with hearing loss, ABR absolute and interwave latencies or OAE amplitudes. As recent postnatal MeHg increased, some associations were found with a few ABR absolute and interwave latencies and a few OAE amplitudes. However, the direction of these associations was inconsistent. As recent postnatal MeHg levels increased the wave I absolute latencies were shorter at 80 dBnHL for all 3 click rates, but the interwave I-V latency was longer for males for the 80 dBnHL 19 clicks/sec and for the III-V interwave latencies for males and females for the dBnHL 69 clicks/sec. Similarly, smaller OAE amplitudes were found at 1500, 2000, and 4000 Hz for males while larger OAE amplitudes were found for females at 1500 and 2000 Hz as the recent postnatal MeHg levels increased. Conclusions No consistent associations were present in this study between prenatal MeHg exposure from consumption of oceanic fish and seafood during pregnancy and auditory functions at 19 years of age. Given the level of prenatal exposure to MeHg, the number of audiologic measures tested, and the presence of the expected sex, click rate, and level dependent findings, it seems unlikely that an association was present and not detected. As recent postnatal MeHg exposure increased, a few associations with ABR latencies and OAE amplitudes were found. The direction of these associations was inconsistent as some showed improved performance as MeHg exposure levels increased ...

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Neurotological Studies upon Intoxication by Organic Mercury Compounds

Cited by 36 publications

References 5 publications

Autoradiographic study of distribution patterns of metals which occur as corrosion products from dental restorations

Autoradiographic study of distribution patterns of metals which occur as corrosion products from dental restorations

Neurophysiologic measures of auditory function in fish consumers: Associations with long chain polyunsaturated fatty acids and methylmercury

Associations between prenatal and recent postnatal methylmercury exposure and auditory function at age 19years in the Seychelles Child Development Study

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