Neuronal activity in the globus pallidus of multiple system atrophy patients.

The pathophysiological changes in neural activity that characterize multiple system atrophy (MSA) are largely unknown. We recorded the activity of pallidal neurons in 3 patients with clinical and radiological features of MSA who underwent unilateral microelectrode-guided pallidotomy for disabling parkinsonism. Findings in these patients were compared with 4 control patients with a clinical diagnosis of Parkinson's disease (PD). The position, firing rates, and firing patterns of single neurons in the pallidal complex were analyzed in both MSA and PD patients. The mean spontaneous firing rate of neurons in the internal segment of the globus pallidus internus (GPii) was significantly lower in MSA than in PD patients. There were no significant differences between MSA and PD patients, however, in firing rates of neurons in the external globus pallidus (GPe) or in the external segment of GPi (GPie). In addition, no significant differences in firing pattern were found between MSA and PD patients. In conclusion, this study has shown that firing rates of neurons in GPii but not in GPie and GPe are different in MSA patients compared with that in PD patients, a finding that may reflect the poor clinical results of pallidotomy reported in patients with MSA.     

Glycolipid and protein profiles of normal and Trypanosoma cruzi infected heart muscle cells.

Using Triton X-114, glycolipids and proteins were extracted from heart muscle cells (HMC) infected with Trypanosoma cruzi clone Dm28c and from uninfected HMC, and analysed by SDS-PAGE and high-performance thin-layer chromatography (HPTLC). Two major differences were observed: (a) two proteins with a molecular mass of 92 kDa and 69 kDa were present in the uninfected cells but absent from the infected cells and (b) a 70-90 kDa protein band was detected only in parasitized cells. These differences would seem to constitute alterations taking place during the process of cell recognition and/or parasite interiorization. No differences were observed in the respective glycolipid compositions, of control and infected cells analysed by HPTLC. A glycolipid with the same mobility as the neutral glycolipid isolated from epimastigotes of T. cruzi was detected in the uninfected cells. This finding may lend support to the previously described hypothesis that molecular mimicry is implicated in the cardioneuropathology of Chagas' disease.     

SPEECH EVALUATION WITH AND WITHOUT PALATAL OBTURATOR IN PATIENTS SUBMITTED TO MAXILLECTOMY

Most patients who have undergone resection of the maxillae due to benign or malignant tumors in the palatomaxillary region present with speech and swallowing disorders. Coupling of the oral and nasal cavities increases nasal resonance, resulting in hypernasality and unintelligible speech. Prosthodontic rehabilitation of maxillary resections with effective separation of the oral and nasal cavities can improve speech and esthetics, and assist the psychosocial adjustment of the patient as well. The objective of this study was to evaluate the efficacy of the palatal obturator prosthesis on speech intelligibility and resonance of 23 patients with age ranging from 18 to 83 years (Mean = 49.5 years), who had undergone inframedial-structural maxillectomy. The patients were requested to count from 1 to 20, to repeat 21 words and to spontaneously speak for 15 seconds, once with and again without the prosthesis, for tape recording purposes. The resonance and speech intelligibility were judged by 5 speech language pathologists from the tape recordings samples. The results have shown that the majority of patients (82.6%) significantly improved their speech intelligibility, and 16 patients (69.9%) exhibited a significant hypernasality reduction with the obturator in place. The results of this study indicated that maxillary obturator prosthesis was efficient to improve the speech intelligibility and resonance in patients who had undergone maxillectomy.