Chronic methylmercurialism in a horse
Chronic methylmercurialism was produced in a horse given 10 g methylmercury chloride over 10 weeks. Neurological signs, particularly proprioceptive disturbances, were apparent by the final week of dosing and became more severe thereafter. An exudative dermatitis, a reluctance to move, weight loss, reduced appetite and dullness were among the earlier clinical signs, and renal changes characterized by a steadily increasing BUN and glucosuria were detected later. Pathological lesions were confined to the kidneys and the nervous system. There was mild neuronal degeneration in the cerebral cortex and in the cerebellar cortex, axonal demyelination in the dorsal columns of the spinal cord and extensive degeneration of ganglion cells in the dorsal root ganglia. The blood organic mercury level, which had plateaued in the second month, increased rapidly in the last weeks of dosing with a sharp rise terminally. This pattern was repeated for the much lower inorganic mercury levels except for a terminal decrease. The proportion of inorganic mercury was five times greater in the dorsal root ganglia than elsewhere in the CNS, although total mercury levels were similar. Highest tissue mercury levels were found in the liver and kidneys, over 50% being in the form of inorganic mercury. As dealkylation of the methylmercury appeared to be more efficient in the dorsal root ganglia and the kidneys, inorganic mercury derived therefrom may have been responsible for some of the clinical and pathological features of this intoxication in the horse. 21 references, 6 figures, 2 tables.
- Research Organization:
- Univ. of Queensland, St. Lucia, Australia
- OSTI ID:
- 5318153
- Journal Information:
- Vet. Hum. Toxicol.; (United States), Journal Name: Vet. Hum. Toxicol.; (United States) Vol. 20:11; ISSN VHTOD
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BLOOD CHEMISTRY
BODY
CENTRAL NERVOUS SYSTEM
CHRONIC EXPOSURE
DIGESTIVE SYSTEM
DISTRIBUTION
ELEMENTS
GLANDS
HORSES
INJURIES
KIDNEYS
LIVER
MAMMALS
MERCURY
MERCURY COMPOUNDS
METABOLISM
METALS
METHYLMERCURY
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANIC MERCURY COMPOUNDS
ORGANS
PATHOLOGICAL CHANGES
TISSUE DISTRIBUTION
TOXICITY
VERTEBRATES