N-methyl-D-aspartate receptor and apoptosis in Alzheimer's disease and multiinfarct dementia.

This study investigates the role of excitotoxicity in Alzheimer's disease and in multiinfarct dementia by examining, via immunohistochemical methods, the number of cells that are positive for N-methyl-D-aspartate (NMDA) receptor and the degree of colocalization between NMDA receptor and apoptosis markers such as TUNEL or activated caspase-3 in the frontal cortex of individuals with these two conditions, comparing the results with those from subjects who died of normal aging. We showed an increased number of NMDA receptor-positive cells and an increased number of TUNEL-labeled cells in the frontal cortex of subjects with Alzheimer's disease, especially in the deeper layers of the cortex. However, only about 10% of cells showed colocalization of NMDA receptor with the apoptosis markers studied, suggesting that NMDA-mediated excitotoxicity does not play a major role in neuronal apoptosis in Alzheimer's disease or in multiinfarct dementia.

Acarbose in NIDDM patients with poor control on conventional oral agents. A 24-week placebo-controlled study.

OBJECTIVE: To determine the efficacy of acarbose, compared with placebo, on the metabolic control of NIDDM patients inadequately controlled on maximal doses of conventional oral agents. RESEARCH DESIGN AND METHODS: In this three-center double-blind study, 90 Chinese NIDDM patients with persistent poor glycemic control despite maximal doses of sulfonylurea and metformin were randomly assigned to receive additional treatment with acarbose 100 mg thrice daily or placebo for 24 weeks, after 6 weeks of dietary reinforcement. Efficacy was assessed by changes in HbA1c, fasting and 1-h postprandial plasma glucose and insulin levels, and fasting lipid levels. RESULTS: Acarbose treatment was associated with significantly greater reductions in HbA1c (-0.5 +/- 0.2% vs. placebo 0.1 +/- 0.2% [means +/- SEM], P = 0.038), 1-h postprandial glucose (-2.3 +/- 0.4 mmol/l vs. placebo 0.7 +/- 0.4 mmol/l, P < 0.001) and body weight (-0.54 +/- 0.32 kg vs. placebo 0.42 +/- 0.29 kg, P < 0.05). There was no significant difference between the two groups regarding changes in fasting plasma glucose and lipids or fasting and postprandial insulin levels. Flatulence was the most common side effect (acarbose vs. placebo: 28/45 vs. 11/44, P < 0.05). One patient on acarbose had asymptomatic elevations in serum transaminases that normalized in 4 weeks after acarbose withdrawal. Another patient on acarbose developed severe hypoglycemia; glycemic control was subsequently maintained on half the baseline dosage of sulfonylurea. CONCLUSIONS: In NIDDM patients inadequately controlled on conventional oral agents, acarbose in moderate doses resulted in beneficial effects on glycemic control, especially postprandial glycemia, and mean body weight. Additional use of acarbose can be considered as a useful alternative in such patients if they are reluctant to accept insulin therapy.