Nocardia otitidiscaviarum (GAM-5) induces parkinsonian-like alterations in mouse

Parkinson's disease, a major neurodegenerative disorder in humans whose etiology is unknown, may be associated with some environmental factors. Nocardia otitidiscaviarum (GAM-5) isolated from a patient with an actinomycetoma produced signs similar to Parkinson's disease following iv injection into NMRI mice. NMRI mice were infected intravenously with a non-lethal dose of 5 x 10(6) colony forming units of N. otitidiscaviarum (GAM-5). Fourteen days after bacterial infection, most of the 60 mice injected exhibited parkinsonian features characterized by vertical head tremor, akinesia/bradykinesia, flexed posture and postural instability. There was a peak of nocardial growth in the brain during the first 24 h followed by a decrease, so that by 14 days nocardiae could no longer be cultured. At 24 h after infection, Gram staining showed nocardiae in neurons in the substantia nigra and occasionally in the brain parenchyma in the frontal and parietal cortex. At 21 days post-infection, tyrosine hydroxylase immunolabeling showed a 58 percent reduction of tyrosine hydroxylase in the substantia nigra, and a 35 percent reduction of tyrosine hydroxylase in the ventral tegmental region. Dopamine levels were reduced from 110 ± 32.5 to 58 ± 16.5 ng/mg protein (47.2 percent reduction) in brain from infected mice exhibiting impaired movements, whereas serotonin levels were unchanged (191 ± 44 protein in control and 175 ± 39 ng/mg protein in injected mice). At later times, intraneuronal inclusion bodies were observed in the substantia nigra. Our observations emphasize the need for further studies of the potential association between Parkinson's disease or parkinsonism-like disease and exposure to various nocardial species.

Aspectos patológicos del músculo esquelético debido a la infección experimental por trypanosoma cruzi / Pathological aspects of skeletal muscle in experimental trypanosoma cruzi infection

En este estudio se muestran los signos clínicos desarrollados por ratones durante la fase aguda de la infección producida por tres cepas de trypanosoma cruzi. Los ratones infectados con la cepa Dm74 sufrieron alteración de la mobilidad de los miembros posteriores y murieron durante la fase aguda de la infección. El análisis histológico del músculo esquelético mostró infiltrado inflamatorio de leucocitos mononucleares y polimorfonucleares, fibroblastos, eritrocitos libres y depósitos de IgG en el espacio intersticial del Gastrocnemius (G). La desintegración de las microfibrillas y cambios en la microvasculatura, fibras nerviosas y en la unión neuromuscular del G fueron también observados. Estos resultados indican que la infección aguda producida por T. cruzi causa daño progresivo en la fibra muscular esquelética y alteración de la actividad motora