Search

Les historiens qui ont ecrit sur l'initiative des Francais entre 1562 et 1565 a la cote sud-est des Etats-Unis d'aujourd'hui ont neglige souvent l'exploration comme facteur motivant. Quand l'on considere le manque de confiance des Europeens dans leur connaissance de cette partie du monde a cette epoquela, il devient clair que l'Amiral Gaspard de Coligny et Jean Ribault, les deux premiers initiateurs de cet effort de colonisation, s'interessaient beaucoup a apprendre plus de la geographie de la region. Les vastes connaissances de Ribault, comme theoricien de geographie au service de l'Angleterre, suggere aussi que la recherche d'une route de navigation a l'Asie etait aussi son intention majeur. Finalement, le temps et l'effort que les Francais depensaient a l'exploration de la cote, des rivieres, et de la terre corroborent l'interpretation que ces expeditions etaient simultanement motivees par un desir a determiner la nature physique de cette region avant de la prendre formellement.

Homogenous eosinophilic intracytoplasmic inclusion bodies were found within the large reticular neurons of the brain stems of 57 captive woodchucks (Marmota monax). Light microscopy was consistent with a proteinaceous nature, while electron microscopy suggested a non-viral origin. The woodchucks with inclusions were older than the general population that was studied. It is hypothesized that the neuronal inclusions in the brain stem are indicative of nonspecific ageing changes.

Brain tumors were found in 42 mice from a total study population of 77,410 mice, which included several strains (BALB/c, C3H, C57BL/6, and hybrids of these strains). The brain tumors were classified on the basis of the new World Health Organization classification of human brain tumors. Tumors originated from neuroepithelial and meningeal tissues, blood vessels, and germ cells. The youngest animal with a tumor was 111 days of age. The tumor incidence was low, being 0.054% of the total study population, with 0.067% in controls and 0.052% in treated mice. Lipomas were the most common type of tumor diagnosed, and they were considered to represent hamartomas rather than true neoplasms. There were 27 brain tumors other than lipomas, the majority (16) of which occurred in BALB/c mice, whereas meningeal tumors (6) were confined to C3H and hybrid strains of mice. The morphologic characteristics of each tumor type are presented.

Two subchronic studies were conducted to assess the potential toxicity of N-D-ornithyl amphotericin B methyl ester (OAME). In both studies the comparative control substance was amphotericin B (AMB). Dogs (5/sex/group) were given OAME (82% pure, based on high-pressure liquid chromatographic (HPLC) analysis) at 0.6, 2.5, and 10 mg/kg or AMB at 0.6 mg/kg intravenously once daily for 3 months. Two dogs per sex per group were retained for a 7-week postdose observation period. Rats (15/sex/group) were given daily doses of OAME at 4, 12, 24, and 36 mg/kg or AMB at 5 and 12 mg/kg intraperitoneally for 3 months. The principal organs of toxicity in both species were the liver, kidneys, and circulating erythrocytes. Hepatic changes in dogs consisted of periportal and centrilobular inflammation in animals of all dosed groups and were equivalent in dogs given 0.6 mg/kg OAME or AMB. In rats, acute hepatic necrosis with periportal, centrilobular, or panlobular distribution in animals of all OAME (except 4 mg/kg) and AMB-dosed groups was observed. These changes were equivalent in the 36-mg/kg OAME- and 12-mg/kg AMB-dosed animals. Renal changes, evidenced by increases in serum urea nitrogen water consumption, urine volume, decreased urine osmolality, and renal tubular changes (ranging from degeneration and regeneration to necrosis), were observed in both species. In dogs, these changes in the OAME-dosed animals were less severe at all doses than those observed in the AMB-dosed dogs. Renal changes in rats, which were mild in comparison to the dogs, were equivalent at doses of 5 and 12 mg/kg AMB and 36 mg/kg OAME. Decreased erythrocyte counts, hematocrit, and hemoglobin values were observed in both species. Unique to the dog study, however, were irreversible behavioral (somnolence, ataxia, tremors, and compulsive searching) and/or morphologic brain changes (gliosis with astrocytic hypertrophy and hyperplasia) at doses of 2.5 and 10 mg/kg OAME. Similar changes were observed in two dogs given 10 mg/kg OAME (100% pure, based on HPLC analysis) in a 6-week pilot study, indicating that the neurological changes were induced by OAME rather than by an impurity. These changes appear related to prolonged exposure to high plasma concentrations of OAME.

GM2-gangliosidosis in animals has been observed in cat, dog and swine.1–4 In 1968, McGrath et al. found a new strain of GM2-gangliosidosis in male German short hair pointer dog which had shown signs of progressive neural dysfunction. Onset of the disease was 10–11 months. Clinical signs initiated by a deterioration of his previously keen response to a whistle, included in sequence: incoordination and postual difficulties, progressive impairment of hearing and vision, psychic changes simulating idiocy, terminal convulsions and prostration. Histological observations showed typical ballooning of the cell bodies of many neurons throughout the nervous system. The intracyto-plasmic materials was Sudan black B and PAS positive. Electron microscopic examination revealed typical MCB as found in human Tay-Sachs disease.4 Clinical and pathological features in dog GM2-gangliosidosis appear to be similar to human Tay-Sachs disease. Brief biochemical features of canine GM2-gangliosidosis were previously reported by Autilio-Gambetti. The present report concerns more detail on chemical and enzymatic analysis in tissues of canine GM2-gangliosidosis.

Meningiomas are the most common central nervous system tumor of the cat, with an age at diagnosis of greater than nine years in 73% of the affected animals. Four of seven cats with alpha-L-iduronidase deficient mucopolysaccharidosis I had meningiomas at postmortem examination. All four cats were less than three years of age. The relationship between the meningiomas and the metabolic defect of MPS I is not clear.

This paper proposes a review of intracranial lesions in the dog as observed at the School of Veterinary Medicine, University of Pennsylvania.