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UNLABELLED 11C-PBR28 PET can detect the 18-kDa translocator protein (TSPO) expressed within macrophages. However, quantitative evaluation of the signal in brain tissue from donors with multiple sclerosis (MS) shows that PBR28 binds the TSPO with high affinity (binding affinity [Ki], ∼4 nM), low affinity (Ki, ∼200 nM), or mixed affinity (2 sites with Ki, ∼4(More)
Neuroinflammation is a pathological hallmark of Alzheimer's disease, but its role in cognitive impairment and its course of development during the disease are largely unknown. To address these unknowns, we used positron emission tomography with (11)C-PBR28 to measure translocator protein 18 kDa (TSPO), a putative biomarker for inflammation. Patients with(More)
UNLABELLED Animal studies and clinical observations suggest that epilepsy is associated with inflammation. Translocator protein (TSPO) (18 kDa), a marker of inflammation, is increased in vitro in surgical samples from patients with temporal lobe epilepsy. TSPO can be measured in the living human brain with PET and the novel radioligand (11)C-PBR28. In this(More)
UNLABELLED Ten percent of humans lack specific binding of [(11)C]PBR28 to 18 kDa translocator protein (TSPO), a biomarker for inflammation. "Non-binders" have not been reported using another TSPO radioligand, [(11)C]-(R)-PK 11195, despite its use for more than two decades. This study asked two questions: (1) What is the cause of non-binding to PBR28? and(More)
UNLABELLED Permeability-glycoprotein (P-gp), an efflux transporter in several organs, acts at the blood-brain barrier to protect the brain from exogenous toxins. P-gp almost completely blocks brain entry of the PET radiotracer (11)C-N-desmethyl-loperamide ((11)C-dLop). We examined the ability of (11)C-dLop to quantify P-gp function in humans after(More)
IMPORTANCE Neuroinflammation may play a role in epilepsy. Translocator protein 18 kDa (TSPO), a biomarker of neuroinflammation, is overexpressed on activated microglia and reactive astrocytes. A preliminary positron emission tomographic (PET) imaging study using carbon 11 ([11C])-labeled PBR28 in patients with temporal lobe epilepsy (TLE) found increased(More)
UNLABELLED We developed a radioligand, 3-fluoro-5-(2-(2-(18)F-(fluoromethyl)thiazol-4-yl)ethynyl)benzonitrile ((18)F-SP203), for metabotropic glutamate subtype 5 (mGluR5) receptors that showed both promising (high specific binding) and problematic (defluorination) imaging characteristics in animals. The purposes of this initial evaluation in human subjects(More)
PURPOSE OF REVIEW In 2011, a new set of new guidelines for the research diagnosis of three stages of Alzheimer disease was promulgated by the US National Institute of Aging and the Alzheimer Association. For the first time, they include the diagnosis of presymptomatic Alzheimer disease, recognizing that the disease process begins years before cognitive(More)
This longitudinal study sought to determine whether the 18 kDa translocator protein (TSPO), a marker of neuroinflammation, increases over time in Alzheimer's disease. Positron emission tomography imaging with the TSPO radioligand (11)C-PBR28 was performed at baseline and after a median follow-up of 2.7 years in 14 amyloid-positive patients and 8(More)