Amyloid PET across the cognitive spectrum in former professional and college American football players: findings from the DIAGNOSE CTE Research Project.

Background: Exposure to repetitive head impacts (RHI) in American football players can lead to cognitive impairment and dementia due to neurodegenerative disease, particularly chronic traumatic encephalopathy (CTE). The pathognomonic lesion of CTE consists of perivascular aggregates of hyper-phosphorylated tau in neurons at the depths of cortical sulci. However, it is unclear whether exposure to RHI accelerates amyloid-β (Aβ) plaque formation and increases the risk for Alzheimer's disease (AD).

Associations between near end-of-life flortaucipir PET and postmortem CTE-related tau neuropathology in six former American football players.

Purpose: Flourine-18-flortaucipir tau positron emission tomography (PET) was developed for the detection for Alzheimer's disease. Human imaging studies have begun to investigate its use in chronic traumatic encephalopathy (CTE). Flortaucipir-PET to autopsy correlation studies in CTE are needed for diagnostic validation.

The Effect of the COVID-19 Pandemic on People with Parkinson's Disease.

Background: The effect of the COVID-19 pandemic on people with Parkinson's disease (PD) is poorly understood.

Objective: To rapidly identify areas of need and improve care in people with PD during the COVID-19 pandemic, we deployed a survey to assess COVID-19 symptoms and the pandemic's effect among those with and without COVID-19.

Methods: People with and without PD participating in the online study Fox Insight (FI) were invited to complete a survey between April 23 and May 23, 2020.

Change in PDE10 across early Huntington disease assessed by [18F]MNI-659 and PET imaging.

Objective: To evaluate whether striatal [(18)F]MNI-659 PET imaging of phosphodiesterase 10A (PDE10) serves as a sensitive and reliable biomarker of striatal neurodegeneration in a longitudinal cohort of participants with early Huntington disease (HD).

Methods: A cohort of participants with HD, including both participants premanifest or manifest with motor signs, underwent clinical assessments, genetic determination, and 2 [(18)F]MNI-659 PET imaging sessions approximately 1 year apart. Eleven healthy control (HC) participants underwent clinical assessments and [(18)F]MNI-659 PET imaging once.

The phosphodiesterase 10 positron emission tomography tracer, [18F]MNI-659, as a novel biomarker for early Huntington disease.

Importance: In Huntington disease (HD) striatal neuron loss precedes and predicts motor signs or symptoms. Current imaging biomarkers lack adequate sensitivity for assessing the early stages of HD. Developing an imaging biomarker for HD spanning the time of onset of motor signs remains a major unmet research need.

Kinetic modeling, test-retest, and dosimetry of 123I-MNI-420 in humans.

Unlabelled: In vivo imaging of adenosine 2A receptors (A2A) in the brain has attracted significant interest from the scientific community, because studies have shown that dysregulation of these receptors is implicated in a variety of neurodegenerative and psychiatric disorders, including Parkinson and Huntington diseases. This work aimed to describe the kinetic properties, test-retest results, and dosimetry estimates of (123)I-MNI-420, a SPECT radiotracer for the in vivo imaging of A2A in the brain.

Methods: Nine healthy human subjects were enrolled in this study; 7 completed (123)I-MNI-420 brain SPECT studies, and 2 participated in whole-body planar imaging evaluating (123)I-MNI-420 biodistribution and dosimetry.

Estimating the half-lives of PCB congeners in former capacitor workers measured over a 28-year interval.

To date, most estimates of the half-life of polychlorinated biphenyls (PCBs) in humans have been based on relatively short follow-up periods. To address this issue, we determined the half-lives of PCB congeners of occupational origin in the serum of former capacitor workers as part of a study conducted in 2003-2006--approximately 28 years after their last occupational exposure. A total of 241 persons from a source population of 6798 former capacitor workers were interviewed and asked to donate a blood sample for serum PCB congener analysis.

Occupational exposure to PCBs reduces striatal dopamine transporter densities only in women: a beta-CIT imaging study.

We hypothesize that occupational exposure to PCBs is associated with a reduction in central dopamine (DA) similar to changes previously seen in PCB exposed adult non-human primates. To test that hypothesis, we used [(123)I]beta-CIT SPECT imaging to estimate basal ganglia DA transporter density in former capacitor workers. Women, but not men, showed an inverse relationship between lipid-adjusted total serum PCB concentrations and DA transporter densities in the absence of differences in serum PCB concentrations.

Striatal dopamine transporters correlate with simple reaction time in elderly subjects.

The decline in motor performance that accompanies advanced age has unclear neurobiological substrates but may relate, in part, to degeneration of the nigrostriatal dopamine system. This research tested the hypothesis that striatal dopamine transporter (DAT) availability in healthy elderly individuals was related to measures of motor performance. Thirty-six healthy volunteers (18 male, 18 female) who ranged in age from 68 to 88 (75.

Double-blind, randomized, controlled trial of rasagiline as monotherapy in early Parkinson's disease patients.

Rasagiline (N-propargyl-1(R)-aminoindan) mesylate is a potent, selective, and irreversible monoamine oxidase-B inhibitor. This study was designed to evaluate the safety, tolerability, and preliminary efficacy of rasagiline monotherapy in early Parkinson's disease (PD) patients not receiving levodopa. The study was performed as a multicenter, parallel-group, double-blind, randomized, placebo-controlled, 10-week study.

The natural history of the syndrome of primary progressive freezing gait.

Background: Primary progressive freezing gait disorder is considered to be a distinct clinical entity that manifests predominantly as a progressive freezing gait disorder without accompanying abnormalities. However, confusion remains about its clinical presentation, natural history, and classification.

Objective: To examine the natural history, clinical and brain imaging characteristics, and response to dopaminergic medications of primary progressive freezing gait (PPFG) disorder.