No abstract

- The rate of dopaminergic loss in PD is significantly greater than that of healthy controls, and [123I]beta-CIT SPECT imaging provides a quantitative biomarker for the progressive nigrostriatal dopaminergic degeneration in PD. As new protective and restorative therapies for PD are developed, dopamine transporter imaging offers the potential to provide an objective endpoint for these therapeutic trials.

We have used in vivo single-photon emission computed tomography (SPECT) of the dopamine transporter with 2 beta-carboxymethoxy-3 beta-(4-iodophenyl)tropane ([123I] beta-CIT) to investigate striatal dopamine transporter loss in patients with early Parkinson's disease (PD). Striatal uptake of ([123I] beta-CIT was compared in eight early-PD patients with exclusively hemi-parkinsonism and eight age- and sex-matched healthy subjects. [123I] beta-CIT striatal uptake was reduced by approximately 53% contralateral and by 38% ipsilateral to the clinically symptomatic side in the hemi-PD patients, compared with the mean striatal uptake in age- and sex-matched healthy subjects. The relative reduction in [123I] beta-CIT uptake in the hemi-PD patients was greater in the putamen than in the caudate. These data demonstrate that SPECT imaging of the dopamine transporter with [123I] beta-CIT can identify patients with PD at the onset of motor symptoms and suggest that this technique also may be useful in identifying individuals with developing dopaminergic pathology before onset of motor symptoms.

Objective: To examine safety, tolerability, and efficacy of PF-04494700, an inhibitor of the receptor for advanced glycation end products (RAGE), in mild to moderate Alzheimer disease (AD).Methods: Double-blind, placebo-controlled trial at 40 academic centers (United States). Subjects with AD and Mini-Mental State Examination score 14-26 were randomized to PF-04494700 60 mg/day 3 6 days, then 20 mg daily (high dose); 15 mg/day 3 6 days, then 5 mg daily (low dose); or placebo, for 18 months. Clinical and laboratory measures were used to evaluate safety and tolerability. The primary efficacy measure was the Alzheimer's Disease Assessment Scale-cognitive (ADAScog). Secondary measures assessed clinical stage, function, behavior, MRI, and CSF biomarkers.Results: A total of 399 subjects were randomized. In a prespecified interim analysis, when 50% of subjects had completed the 6-month visit, the high dose was associated with confusion, falls, and greater ADAS-cog decline and was discontinued. A second prespecified analysis compared lowdose and placebo groups for futility and safety approximately 12 months after all subjects were randomized. This analysis met criteria for futility, and treatment was discontinued. There were no safety concerns in the low-dose group. Analyses including post-futility data showed decreased decline on the ADAS-cog in the low-dose group at month 18. Other clinical and biomarker measures showed no differences between low-dose treatment and placebo.Conclusions: PF-04494700 at 20 mg/d was associated with increased adverse events and cognitive decline. At 5 mg/d, PF-04494700 had a good safety profile. A potential benefit for this low dose on the ADAS-cog is not conclusive, because of high dropout and discontinuation rates subsequent to the interim analyses.

These results suggest that the NPY Pro7 allele is a risk factor for alcohol dependence. This is only the second specific genetic mechanism ever identified that modulates risk for alcohol dependence.