Uncommon neurological presentations of tuberculoma.

The neurological manifestations and autopsy findings of 3 cases of tuberculoma have been described. A cerebello-pontine angle tuberculoma presented with a long history of trigeminal neuralgia. Intramedallary tuberculoma of the spinal cord presented with transverse myelitis, history of one complete remission and a normal myelogram. A tuberculoma of the medulla led to, apart from other features, severe orthostatic hypotension. Tuberculous meningitis, as a terminal process, developed in the first two cases and the third patient died from a vasomotor collapse on suddenly standing up from bed.     

Involvement of excitatory amino acid mechanisms in gamma-hydroxybutyrate model of generalized absence seizures in rats.

gamma-Hydroxybutyric acid (GHB), a naturally occurring compound which is synthesized from gamma-aminobutyric acid (GABA), induces bilaterally synchronous spike wave discharges, associated with behavioral changes, reminiscent of petit mal or generalized absence seizures in rats. In the present study, possible involvement of excitatory amino acids (EAAs) in GHB-induced spike wave discharges was investigated. The noncompetitive antagonist of NMDA receptors, MK-801, attenuated GHB-induced spike wave discharges at all doses tested (0.025-1.0 mg/kg) but dose-dependently induced suppression of EEG bursts in GHB-treated animals. The suppression of bursts was never observed with GHB in control experiments. N-Methyl-D-aspartate (NMDA) had a similar effect on GHB-induced spike wave discharges, when it was administered prior to GHB. This effect of NMDA was partially reversed by MK-801. The competitive antagonists of NMDA receptors, (+/-)CPP and CGP 43487 and the antagonist at the strychnine-insensitive glycine site, HA-966, also suppressed GHB-induced spike wave discharges with the EEG progressing to suppression of bursts but were weaker in this regard than MK-801 or NMDA. These data raise the possibility of involvement of excitatory amino acids in the GHB model of absence seizures.     

Animal model for theophylline--cimetidine drug interaction

Cimetidine (300 mg I.V.) and theophylline (15 mg/kg I.V.) were studied in Beagle dogs for possible drug interaction. The drugs were administered alone and in combination using a crossover design. Although none of the determined pharmacokinetic parameters for theophylline changed significantly in the presence of cimetidine, a trend towards significance was found for the terminal half-life, area under the curve, and mean residence time. The magnitude in changes found in Beagles is representative of the changes reported in man.