Visual, auditive and somatosensory pathways alterations in geriatric rhesus monkeys (Macaca mulatta).

BACKGROUND: Synapses loss during aging is associated to neurophysiologic alterations that impair organism's health span, thus making the study and prevention of sensory decline relevant for healthy aging and welfare. Therefore the aim of this study was to obtain normative data related to the electrophysiological responses of the different neurosensory components in the visual, auditory and somatosensory pathways in healthy geriatric rhesus monkeys in captivity. METHODS: Twenty-four rhesus monkeys were divided in two groups: (i) Geriatric monkeys, 20-30 years of age, and (ii) Young monkeys, 7 years of age. Evoked potentials were obtained from the visual, auditory and somatosensory pathways. RESULTS: Regardless the sensory pathways evaluated, a significant delay in nerve conduction was observed in the geriatric group in comparison to the young group. CONCLUSIONS: Evoked potentials allowed identifying changes generated during aging in rhesus monkeys and normative data for this species were obtained.

Edema and tetraparesis in a miniature pig after allogeneic hematopoietic cell transplantation.

A 3-mo-old, 12-kg, intact, miniature pig presented with severe neurologic signs on day 8 after hematopoietic cell transplantation. This pig had received an immunosuppressive regimen before transplantation that included an antiCD3 immunotoxin for T-cell depletion, 100 cGy of total-body irradiation, and cyclosporine for 45 d. The pig began exhibiting erythematous lesions on posttransplantation day 7. He also demonstrated increased conscious proprioceptive deficits and recumbency but normal mentation. Neurologic signs worsened over several days; the pig became lethargic but remained afebrile. Conjunctival swelling developed on posttransplantation day 9, which subsequently spread to the animal's head, ears and hocks by day 10. Analgesics were given for pain, and cyclosporine levels were decreased. Despite the measures taken, neurologic signs progressed. Given the worsening subcutaneous edema and neurologic status, Escherichia coli infection was suspected, and treatment with a third-generation cephalosporin was instituted. The clinical signs resolved within 12 h after the start of antibiotics. 'Shiga-like' toxin from E. coli can cause peracute toxemia and induce ataxia, paralysis, and recumbency. Other common and pathognomonic findings include periocular edema and variable edema in other subcutaneous regions. A fecal sample demonstrated an overgrowth of gram-negative, lactose-fermenting colonies. On the basis of the clinical presentation, exclusion of other potential conditions compatible with edema and neurologic diseases, physical exam findings, microbiology and the resolution of signs after therapy, the pig was diagnosed with edema disease.

Intracranial cholesterol granuloma in a cat.

A case of intracranial cholesterol granuloma is described in a 4-year-old neutered European male cat presented with a 5-month history of progressive weakness, ataxia and depression. On clinical evaluation, haematological and biochemical profiles revealed only mild hypercholesterolemia and magnetic resonance imaging showed a large space-occupying extra-axial mass in the area of the falx, not homogeneous after contrast enhancement. At post-mortem examination, an orange-yellowish mass of 22 mm in diameter extended from the right frontal lobe to the temporo-parietal region, causing atrophy of the prosencephalic region of the brain. The site of origin of the mass was within the subarachnoid space of the supracallosum sulcus of the right cerebral hemisphere. Histological examination of the lesion revealed abundant deposits of cholesterol clefts, surrounded by clusters of macrophages and multinucleated giant cells. Neither inflammatory lesions, nor cholesterol deposits were detected in other areas of the brain and in other organs. On the basis of the histological examination, a diagnosis of intracranial cholesterol granuloma was made.