Investigations of neurotoxicity and neuroprotection within the nucleus basalis of the rat

The present study investigated the specific ways by which cytotoxicity due to glutamate receptor stimulation could be attenuated by the administration of agonists and antagonists of the ionotropic and metabotropic glutamate receptors within the nucleus basalis magnocellularis (NBM) of rats as measured by cortical choline acetyltransferase activity. The results of these studies suggest that (1) the cytotoxicity of ibotenate to NBM cholinergic cells is not dependent upon stimulation of metabotropic glutamate receptors, but results from activation of (NMDA) receptors, (2) the cytotoxicity of quisqualate to cholinergic cells within the NBM is not dependent upon stimulation of NMDA or metabotropic receptors, and (3) the cytotoxicity of NMDA was prevented by administration (i.p.) of the un-competitive NMDA antagonist memantine (30 mg/kg), resulting in plasma levels of 2.5 μg/ml, a concentration known to block efficiently NMDA receptors in vitro. Finally, performance of a food-motivated, delayed-alternation task on a T-maze was impaired by injections of NMDA into the NBM, but was prevented by co-administration of NMDA with memantine.     

Phonological features of child African American English.

The production of phonological features of African American English (AAE) was examined for 64 typically developing African American children in the 2nd through the 5th grade. Students read aloud passages written in Standard American English. Sixty of the students read the passages using AAE, and 8 different phonological features were represented in their readings. Phonological features were more frequent than morphosyntactic features. The findings as a whole support use of the taxonomy developed for this investigation in characterizing the phonological features of child AAE.     

Uropathogenicity in rats and mice of Providencia stuartii from long-term catheterized patients

Providencia stuartii, a frequent and persistent isolate from the urinary tract of chronically catheterized elderly patients, is multiply antibiotic resistant and may cause fatal bacteremia in those patients. We studied P. stuartii strains in rats and mice to determine differences in uropathogenicity. Strains studied varied in expression of factors which contribute to pathogenicity of other bacterial species. Urinary tract responses following challenge with P. stuartii strain HO (factors expressed) were similar to responses reported for uropathogenic E. coli strains both in bacterial persistence and histologic change. In animals similarly challenged with P. stuartii strain RO (factors not expressed), responses were similar to those reported for non-uropathogenic E. coli strains. Results indicate that: a) animal model studies may be useful in differentiating P. stuartii strains based on uropathogenicity, b) P. stuartii uropathogenicity may be related to identifiable factors associated with virulence in other species, and c) the CBA mouse model appears to be the most suitable for studies of P. stuartii uropathogenicity.