[The vestibular system and cerebellum in organic mercury intoxication; an otolaryngological and neuropathological investigation on 14 autopsy cases in Niigata].
The vestibular system consisting of vestibular ganglion, nerve and inferior, medial, lateral and superior nuclei and fastigial nucleus, cerebellar vermis, flocculus and hemisphere in 14 autopsy cases of methyl mercury intoxication in Niigata and 12 age-matched controls were examined neuropathologically. The findings were evaluated semiquantitatively, that is, -; normal, +/-; gliosis alone, +; loss of neurons or myelinated fibers less than about 40%, ++; loss of neurons from about 41 to 80%, ; loss of neurons more than about 81%. The results were compared to the records of the equilibrium function of those patients. The examinations on the equilibrium function revealed positive findings in the optokinetic and positional nystagmus, eye tracking, Mann or Stepping test in many of the patients. There were no remarkable histological alterations in the vestibular ganglion and nerve of the patients. Moderate and diffuse gliosis with slight shrinkage of neurons were observed in the vestibular and fastigial nuclei of all the patients. Slight loss of neurons in various vestibular nuclei was examined in only 4 patients. The fastigial nucleus showed no evident loss of neurons. In contrast, the cerebellum showed diffuse loss of Purkinje and granule cells, the degree of which was higher in the vermis than in the hemisphere and the flocculus. In the controls, the vestibular nerve and nuclei showed no remarkable alteration even in eight decade subjects. However, the Purkinje cells in the vermis seemed to have a tendency to decrease in aging. The dysequilibrium in the patient of methyl mercury intoxication did not seem to be correspond to the degeneration of the vestibular ganglion, nerve or nuclei.(ABSTRACT TRUNCATED AT 250 WORDS)
Oyanagi
K
K
Center for Materials of Brain Diseases, Niigata University, Japan.
Ohama
E
E
Ikuta
F
F
Igarashi
S
S
Nakano
Y
Y
D000368:Aged; D000369:Aged, 80 and over; D002531:Cerebellum / Q000187:drug effects / Q000473:pathology*; D005260:Female; D005911:Gliosis / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology; D006309:Hearing / Q000187:drug effects; D006801:Humans; D007564:Japan; D008297:Male; D008767:Methylmercury Compounds / Q000506:poisoning*; D008875:Middle Aged; D009474:Neurons / Q000187:drug effects / Q000473:pathology; D009760:Nystagmus, Physiologic / Q000187:drug effects; D004856:Postural Balance / Q000187:drug effects; D014725:Vestibular Nerve / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology; D014726:Vestibular Nuclei / Q000187:drug effects / Q000473:pathology*; D000160:Vestibulocochlear Nerve Diseases / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology
D008767:Methylmercury Compounds