Subject(s)
Malus , Psychotic Disorders , Pyrus , Schizophrenia , Humans , Neuroglia , Receptors, GABAABSTRACT
Several lines of evidence are indicative of a role for immune activation in the pathophysiology of schizophrenia. Nevertheless, studies using positron emission tomography (PET) and radioligands for the translocator protein (TSPO), a marker for glial activation, have yielded inconsistent results. Whereas early studies using a radioligand with low signal-to-noise in small samples showed increases in patients, more recent studies with improved methodology have shown no differences or trend-level decreases. Importantly, all patients investigated thus far have been on antipsychotic medication, and as these compounds may dampen immune cell activity, this factor limits the conclusions that can be drawn. Here, we examined 16 drug-naive, first-episode psychosis patients and 16 healthy controls using PET and the TSPO radioligand [11C]PBR28. Gray matter (GM) volume of distribution (VT) derived from a two-tissue compartmental analysis with arterial input function was the main outcome measure. Statistical analyses were performed controlling for both TSPO genotype, which is known to affect [11C]PBR28 binding, and gender. There was a significant reduction of [11C]PBR28 VT in patients compared with healthy controls in GM as well as in secondary regions of interest. No correlation was observed between GM VT and clinical or cognitive measures after correction for multiple comparisons. The observed decrease in TSPO binding suggests reduced numbers or altered function of immune cells in brain in early-stage schizophrenia.
Subject(s)
Neuroglia/chemistry , Psychotic Disorders/diagnostic imaging , Receptors, GABA/analysis , Schizophrenia/metabolism , Acetamides , Adult , Biomarkers/metabolism , Brain/diagnostic imaging , Brain/metabolism , Carbon Radioisotopes , Case-Control Studies , Female , Gray Matter/diagnostic imaging , Gray Matter/microbiology , Humans , Male , Microglia/metabolism , Neuroglia/metabolism , Neuroglia/pathology , Positron-Emission Tomography/methods , Pyridines , Radioligand Assay , Radiopharmaceuticals , Receptors, GABA/metabolism , Schizophrenia/diagnostic imaging , Schizophrenia/pathologyABSTRACT
Knowledge of the abundance of H(3)(+) is needed in interstellar and planetary atmospheric chemistry. An important destruction mechanism of H(3)(+) is low-energy electron impact followed by dissociation, but estimates of the reaction rate span several orders of magnitude. As an attempt to resolve this uncertainty, the cross section for dissociative recombination of vibrationally cold H(3)(+) has been measured with an ion storage ring down to collision energies below 1 millielectron volt. A rate coefficient of 1.15 x 10(-7) cubic centimeters per second at 300 kelvin was deduced. The cross section scaled with collision energy according to E(-1.15), giving thee rate a temperature dependence of T(-0.65).
