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This study experimentally investigated the atomic structure of a single-crystalline Mn-doped BiFeO3 (BFO) thin film using X-ray fluorescence holography with synchrotron radiation. Bi atoms can be reconstructed from both Fe Kβ and Mn Kα fluorescence X-ray holograms, indicating Mn doping at B sites in ABO3-type perovskite structure. The fluorescence intensity of the 1st to 4th nearest Bi atoms around target Fe atoms was lower than those around Mn atoms, confirming the selective formation of Bi vacancies around Fe atoms. In contrast, the 5th to 8th nearest Bi atoms around Fe atoms showed higher intensities than those around Mn atoms, indicating that the Mn-doped BFO thin film had a double-perovskite-like structure. These results provide important information that helps elucidate the mechanism by which Mn doping modifies the conductivity of BFO. [ABSTRACT FROM AUTHOR]

Inflammatory/immunological process and glial contribution are suggested in the pathophysiology of schizophrenia. We investigated peripheral benzodiazepine receptors in brains of patients with chronic schizophrenia, which were reported to be located on mitochondria of glial cells, using [11C]DAA1106 with positron emission tomography. Fourteen patients and 14 age- and sex-matched normal controls participated in this study. PET data were analysed by two-tissue compartment model with metabolite-corrected plasma input. Clinical symptoms were assessed using the Positive and Negative Syndrome Scale. There was no significant difference between [11C]DAA1106 binding of the cortical regions of normal controls and patients with schizophrenia, whereas the patients showed a positive correlation between cortical [11C]DAA1106 binding and positive symptom scores. There was also a positive correlation between [11C]DAA1106 binding and duration of illness. Although the correlations need to be interpreted very cautiously, involvement of glial reaction process in the pathophysiology of positive symptoms or progressive change of schizophrenia might be suggested. [ABSTRACT FROM AUTHOR]

Abstract: The serotonin transporter (5-HTT) and other markers of the serotonergic system have been of interest in the pathophysiology of obsessive-compulsive disorder (OCD). Previous studies using single photon emission computed tomography (SPECT) with [123I]β-CIT or positron emission tomography (PET) with [11C]McN5652 have not shown consistent findings about 5-HTT in OCD patients. The aim of the present study was to investigate 5-HTT binding using [11C]DASB, which has higher selectivity or specific binding-to-nonspecific binding ratios for 5-HTT compared to the aforementioned radioligands. Four drug-naive and 6 drug-free patients with OCD who were free of comorbid depression and 18 gender and age-matched healthy subjects underwent PET scans with [11C]DASB. The severity of OCD was assessed by Yale–Brown Obsessive–Compulsive Scale (Y-BOCS) (mean±SD: 22±7.6, range: 7–32). The binding potential (BP ND ) of [11C]DASB was calculated using a two-parameter multilinear reference tissue model (MRTM2). The parametric images of BP ND were analyzed using a statistical parametric mapping system. Significant reductions of BP ND were observed in the right posterior and left anterior insular cortices in patients with OCD compared to controls. Region-of-interest analysis has also confirmed significant reduction of BP ND in the insular cortex. Although significantly reduced BP ND in the orbitofrontal cortex was also observed in patients with OCD compared to controls, this finding should be considered with caution because of the very low 5-HTT binding in the region. On the other hand, no significant correlation was observed between the Y-BOCS score and BP ND . The change in [11C]DASB binding in the insular cortex suggests that dysfunction of the serotonergic system in the limbic area might be involved in the pathophysiology of OCD. [Copyright &y& Elsevier]

N-methyl- D-aspartate (NMDA) receptors are of major interest in brain functions and neuropsychiatric disorders. However, at present there are few suitable radioligands for in vivo imaging of NMDA receptors. 7-Choloro-4-hydroxy-3-[3-(4-methoxybenzyl) phenyl]-2(1 H)-quinolone (L-703,717) is one of the potent ligands for the glycine-binding site of NMDA receptors. 4-Acetoxy derivative of L-703,717 (AcL703) is a candidate, as a positron emission tomography (PET) ligand for NMDA receptors, because of its better permeability at the blood-brain barrier compared with L-703,717. After intravenous injection of 624-851 MBq of [11C]AcL703, dynamic PET scan was performed on six healthy males for 90 min. Regions-of-interest were located on the cerebral cortices, cerebellar cortex, and cerebral white matter. The binding potential (BP) was calculated from the ratio of the area under the curve (AUC) of radioactivities from 40 to 90 min in the target region to that in white matter. Regional radioactivities reached close to equilibrium in all regions after about 40 min postinjection. Regional brain uptake of [11C]AcL703 at 40 min after injection was 0.00028-0.00065% of the injected dose/milliliter. Radioactivity concentration of [11C]AcL703 was highest in the cerebellar cortex and lowest in white matter. AUC in the cerebellar cortex was higher than those of cerebral cortices, thalamus, striatum, and white matter. BP in the cerebellar cortex was twofold higher than in the cerebral cortices (cerebellar cortex: BP = 2.20 ± 0.72; cerebral cortices: BP = 1.05 ± 0.45). Despite the low brain uptake of [11C]AcL703, regional distributions were in good agreement with our previous studies of rodents. This indicates the possibility of in vivo evaluation of NMDA receptors using PET with [11C]AcL703 in living human brain. Synapse 61:795-800, 2007. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]