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[ 18F]FDG uptake in axillary lymph nodes and deltoid muscle after COVID-19 mRNA vaccination: a cohort study to determine incidence and contributing factors using a multivariate analysis. Ann Nucl Med 2022; 36:340-350. [PMID: 35098436 PMCID: PMC8801267 DOI: 10.1007/s12149-021-01711-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 12/19/2021] [Indexed: 11/05/2022]
Abstract
PURPOSE Reactive FDG uptake in the axillary lymph nodes (ALN) and deltoid muscle (DM) after COVID-19 mRNA vaccination has been recognized, although the actual situation in the Japanese population remains unknown. To determine the incidence of reactive FDG uptake and its contributing factors, we retrospectively studied a cohort of subjects who were vaccinated at our hospital. METHODS Whole-body FDG-PET/CT examinations performed in 237 subjects out of 240 subjects with a definite history of COVID-19 vaccination (BNT162b2; BioNTech-Pfizer) were analyzed. Positivity and SUVmax of FDG uptake in the ALN and DM ipsilateral to vaccination, various subject characteristics, and the grade of the pathological FDG-PET/CT findings were evaluated using a multivariate analysis. RESULTS FDG uptake in the ALN and DM ipsilateral to vaccination was seen in about 60% of the subjects even soon (0-4 days) after the first vaccination, with percentages reaching 87.5% and 75.0%, respectively, after the second vaccination. DM uptake had almost disappeared at around 2 weeks, while ALN uptake persisted for 3 weeks or longer. A multivariate analysis showed that a short duration since vaccination, a younger age, a female sex, and a low FDG-PET/CT grade (minimal pathological FDG uptake) contributed significantly to positive ALN uptake, while a short duration since vaccination and a female sex were the only significant contributors to positive DM uptake. This study is the first to identify factors contributing to positive FDG uptake in ALN and DM after COVID-19 vaccination. CONCLUSION A high incidence of FDG uptake in ALN and DM was observed after vaccination. ALN uptake seemed to be associated with a younger age, a female sex, and minimal pathological FDG uptake. After vaccination, an acute inflammatory reaction in DM followed by immune reaction in ALN linked to humoral immunity may be speculated.
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Adenosine A 2A Receptor Occupancy by Caffeine After Coffee Intake in Parkinson's Disease. Mov Disord 2022; 37:853-857. [PMID: 35001424 PMCID: PMC9306703 DOI: 10.1002/mds.28897] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 11/26/2022] Open
Abstract
Background Coffee intake can decrease the risk for Parkinson's disease (PD). Its beneficial effects are allegedly mediated by caffeine through adenosine A2A receptor (A2AR) antagonist action. Objective We aimed to calculate occupancy rates of striatal A2ARs by caffeine after coffee intake in PD. Methods Five patients with PD underwent 11C‐preladenant positron emission tomography scanning at baseline and after intake of coffee containing 129.5 mg (n = 3) or 259 mg (n = 2) of caffeine. Concurrently, serum caffeine levels were measured. Results The mean serum caffeine level (μg/mL) was 0.374 at baseline and increased to 4.48 and 8.92 by 129.5 and 259 mg of caffeine, respectively. The mean occupancy rates of striatal A2ARs by 129.5 and 259 mg of caffeine were 54.2% and 65.1%, respectively. Conclusions A sufficient A2AR occupancy can be obtained by drinking a cup of coffee, which is equivalent to approximately 100 mg of caffeine. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Test-retest reproducibility of cerebral adenosine A 2A receptor quantification using [ 11C]preladenant. Ann Nucl Med 2021; 36:15-23. [PMID: 34564828 DOI: 10.1007/s12149-021-01678-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 09/13/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To evaluate the reproducibility of cerebral adenosine A2A receptor (A2AR) quantification using [11C]preladenant ([11C]PLN) and PET in a test-retest study. METHODS Eight healthy male volunteers were enrolled. Dynamic 90 min PET scans were performed twice at the same time of the day to avoid the effect of diurnal variation. Subjects refrained from caffeine from 12 h prior to scanning, and serum caffeine was measured before radioligand injection. Arterial blood was sampled repeatedly during scanning and the fraction of the parent compound in plasma was determined. Total distribution volume (VT) was estimated using 1- and 2-tissue compartment models (1-TCM and 2-TCM, respectively) and Logan graphical analysis (Logan plot) (t* = 30 min). Plasma-free fraction (fP) of [11C]PLN was measured and used for correction of VT values. Distribution volume ratio (DVR) was calculated from VT of target and reference regions and obtained by noninvasive Logan graphical reference tissue model (LGAR) (t* = 30 min). Absolute test-retest variability (aTRV), and intra-class correlation coefficient (ICC) of VT and DVR were calculated as indexes of repeatability. Correlation between DVR and serum concentration of caffeine (a nonselective A2AR blocker) was analyzed by Pearson's correlation analysis. RESULTS Regional time-activity curves were well described by 2-TCM models. Estimation of VT by 2-TCM produced some erroneous values; therefore, the more robust Logan plot was selected as the appropriate model. Global mean aTRV was 20% for VT and 14% for VT/fP (ICC, 0.72 for VT and 0.87 for VT/fP). Global mean aTRV of DVR was 13% for Logan plot and 10% for LGAR (ICC, 0.70 for Logan plot and 0.81 for LGAR). DVR estimates using LGAR and Logan plot were in good agreement (r2 = 0.96). Coefficients of variation for VT, VT/fP, DVR (Logan plot), and DVR (LGAR) were 47%, 47%, 27%, and 18%, respectively. Despite low serum caffeine levels, significant concentration-dependent effects on [11C]PLN binding to target regions were observed (p < 0.01). CONCLUSIONS In this study, moderate test-retest reproducibility and large inter-subject differences were observed with [11C]PLN PET, possibly attributable to competition by baseline amount of caffeine. Analysis of plasma caffeine concentration is recommended during [11C]PLN PET studies. TRIAL REGISTRATION UMIN000030040.
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Adenosine A 2A Receptor Occupancy by Long-Term Istradefylline Administration in Parkinson's Disease. Mov Disord 2020; 36:268-269. [PMID: 33200448 PMCID: PMC7894182 DOI: 10.1002/mds.28378] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 11/28/2022] Open
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Synthesis and evaluation of N-isopropyl-p-[ 11C]methylamphetamine as a novel cerebral blood flow tracer for positron emission tomography. EJNMMI Res 2020; 10:115. [PMID: 33000345 PMCID: PMC7527401 DOI: 10.1186/s13550-020-00702-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/17/2020] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Increases in fasting plasma glucose (PG) levels lead to a decrease in 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake in the normal brain, especially in the precuneus, resulting in an Alzheimer's disease (AD)-like uptake pattern. Therefore, patients with higher PG levels, such as those with diabetes, can be erroneously diagnosed with AD when positron emission tomography (PET) imaging is done using [18F]FDG, due to reduced uptake of [18F]FDG in the precuneus. To help avoid an erroneous diagnosis of AD due to differences in glucose metabolism, evaluating cerebral blood flow (CBF) in the brain is useful. However, current techniques such as single photon emission computed tomography (SPECT) and [15O]H2O PET have limitations regarding early diagnosis of AD because the images they produce are of low resolution. Here, we developed a novel CBF PET tracer that may be more useful than [18F]FDG for diagnosis of AD. METHODS We synthesized and evaluated N-isopropyl-p-[11C]methylamphetamine ([11C]4) as a carbon-11-labeled analogue of the standard CBF SPECT tracer N-isopropyl-p-[123I]iodoamphetamine. Fundamental biological evaluations such as biodistribution, peripheral metabolism in mice, and brain kinetics of [11C]4 in non-human primates with PET with successive measurement of [15O]H2O were performed. RESULTS [11C]4 was synthesized by methylation of the corresponding tributyltin precursor (2) with [11C]MeI in a palladium-promoted Stille cross-coupling reaction. The brain uptake of [11C]4 in mice peaked at 5-15 min after injection and then promptly decreased. Most radioactivity in the brain was detected in the unchanged form, although in the periphery, [11C]4 was rapidly metabolized to hydrophilic components. Acetazolamide (AZM) treatment significantly increased the brain uptake of [11C]4 without affecting the blood levels of radioactivity in mice. Preliminary kinetics analysis showed that the K1 of [11C]4 reflected regional CBF in a vehicle-treated monkey, but that the K1 did not reflect CBF in higher flow regions after AZM loading. CONCLUSION [11C]4 is a potential novel CBF PET tracer. Further validation studies are needed before [11C]4 can be used in humans.
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Pre-discard estimation of radioactivated materials in positron emission tomography cyclotron systems and concrete walls of a cyclotron vault. Med Phys 2019; 46:2457-2467. [PMID: 30870578 DOI: 10.1002/mp.13492] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/20/2019] [Accepted: 03/07/2019] [Indexed: 11/12/2022] Open
Abstract
PURPOSE The concrete vault, cyclotron body, and peripheral equipment in a cyclotron room become radioactivated by neutrons generated by operating an unshielded cyclotron. Radionuclides and the amounts of radioactivated materials must be identified before discarding a cyclotron system. The present study aimed to reduce the amounts of concrete from cyclotron vaults, as well as cyclotron components and peripheral equipment, that will be disposed of as radioactivated waste by clarifying the nature and quantity of radioactivated materials remaining in facilities after cyclotron operations have ceased. METHODS Cylindrical concrete cores were bored into all four walls, ceiling, and floor of a room where a Cypris 370 cyclotron had been operated for 22.8 yr and then cooled for 40 months. The accelerated particles comprised protons and deuterons with constant energy of 18 and 10 MeV, respectively. The types and amounts of radionuclides in these cores, in 38 components of the cyclotron including the yoke, and in 13 pieces of equipment in the room, were determined by γ-ray spectrometry. Concentrations of radioactivity were also calculated using an updated version of Particle and Heavy Ion Transport System and DCHAIN-SP. Amounts of materials with both measured and calculated total radioactivity concentration (ΣD) of <0.1 Bq/g were identified as being nonradioactivated. RESULTS The major radionuclides in the concrete were 60 Co and 152 Eu. The radioactivated concrete was distributed to a depth of <38 cm. Most cyclotron components and equipment were radioactivated by neutrons. The major radionuclides in cyclotron components and equipment were 54 Mn, 60 Co, and 65 Zn. A 33% volume of the yoke was regarded as nonradioactivated. CONCLUSIONS The estimated amount of radioactivated waste in the concrete was about 70,000 kg (12.5% of the total concrete). Most components of the cyclotron except for the 33% volume of the yoke (20% of the cyclotron body), as well as most peripheral equipment in the room, were radioactivated. Part-by-part assessments of radioactive materials using measurements and calculations could distinguish nonradioactive from radioactive materials before they are discarded.
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4-Borono-2- 18F-fluoro-L-phenylalanine PET for boron neutron capture therapy-oriented diagnosis: overview of a quarter century of research. Ann Nucl Med 2019; 33:223-236. [PMID: 30820862 PMCID: PMC6450856 DOI: 10.1007/s12149-019-01347-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/17/2019] [Indexed: 11/29/2022]
Abstract
4-10B-Borono-2-18F-fluoro-L-phenylalanine (18F-FBPA) was developed for monitoring the pharmacokinetics of 4-10B-borono-L-phenylalanine (10B-BPA) used in boron neutron capture therapy (BNCT) with positron emission tomography (PET). The tumor-imaging potential of 18F-FBPA was demonstrated in various animal models. Accumulation of 18F-FBPA was higher in melanomas than in non-melanoma tumors in animal models and cell cultures. 18F-FBPA was incorporated into tumors mediated mainly by L-type amino acid transporters in in vitro and in vivo models. Tumoral distribution of 18F-FBPA was primarily related to the activity of DNA synthesis. 18F-FBPA is metabolically stable but is incorporated into melanogenesis non-enzymatically. These in vitro and in vivo characteristics of 18F-FBPA corresponded well to those of 10B-BPA. Nuclear magnetic resonance and other studies using non-radioactive 19F-10/11B-FBPA also contributed to characterization. The validity and reliability of 18/19F-FBPA as an in vivo probe of 10B-BPA were confirmed by comparison of the pharmacokinetics of 18F-FBPA and 10B-BPA and direct measurement of both 18F and 10B in tumors with various doses of both probes administered by different routes and methods. Clinically, based on the kinetic parameters of dynamic 18F-FBPA PET, the estimated 10B-concentrations in tumors with continuous 10B-BPA infusion were similar to those measured directly in surgical specimens. The significance of 18F-FBPA PET was verified for the estimation of 10B-concentration and planning of BNCT. Later 18F-FBPA PET has been involved in 10B-BPA BNCT of patients with intractable tumors such as malignant brain tumors, head and neck tumors, and melanoma. Usually a static PET scan is used for screening patients for BNCT, prediction of the distribution and accumulation of 10B-BPA, and evaluation of treatment after BNCT. In some clinical trials, a tumor-to-normal tissue ratio of 18F-FBPA > 2.5 was an inclusion criterion for BNCT. Apart from BNCT, 18F-FBPA was demonstrated to be a useful PET probe for tumor diagnosis in nuclear medicine: better tumor-to-normal brain contrast compared with 11C-methionine, differentiation of recurrent and radiation necrosis after radiotherapy, and melanoma-preferential uptake. Further progress in 18F-FBPA studies is expected for more elaborate evaluation of 10B-concentrations in tumors and normal tissues for successful 10B-BPA BNCT and for radiosynthesis of 18F-FBPA to enable higher 18F-activity amounts and higher molar activities.
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Increased Binding Potential of Brain Adenosine A1 Receptor in Chronic Stages of Patients with Diffuse Axonal Injury Measured with [1-methyl-11C] 8-dicyclopropylmethyl-1-methyl-3-propylxanthine Positron Emission Tomography Imaging. J Neurotrauma 2018; 35:25-31. [DOI: 10.1089/neu.2017.5006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Age-Related Decrease in Male Extra-Striatal Adenosine A 1 Receptors Measured Using11C-MPDX PET. Front Pharmacol 2017; 8:903. [PMID: 29326588 PMCID: PMC5741655 DOI: 10.3389/fphar.2017.00903] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/28/2017] [Indexed: 11/15/2022] Open
Abstract
Adenosine A1 receptors (A1Rs) are widely distributed throughout the entire human brain, while adenosine A2A receptors (A2ARs) are present in dopamine-rich areas of the brain, such as the basal ganglia. A past study using autoradiography reported a reduced binding ability of A1R in the striatum of old rats. We developed positron emission tomography (PET) ligands for mapping the adenosine receptors and we successfully visualized the A1Rs using 8-dicyclopropylmethyl-1-11C-methyl-3-propylxanthine (11C-MPDX). We previously reported that the density of A1Rs decreased with age in the human striatum, although we could not observe an age-related change in A2ARs. The aim of this study was to investigate the age-related change of the density of A1Rs in the thalamus and cerebral cortices of healthy participants using 11C-MPDX PET. We recruited eight young (22.0 ± 1.7 years) and nine elderly healthy male volunteers (65.7 ± 8.0 years). A dynamic series of decay-corrected PET scans was performed for 60 min starting with the injection of 11C-MPDX. We placed the circular regions of interest of 10 mm in diameter in 11C-MPDX PET images. The values for the binding potential (BPND) of 11C-MPDX in the thalamus, and frontal, temporal, occipital, and parietal cortices were calculated using a graphical analysis, wherein the reference region was the cerebellum. BPND of 11C-MPDX was significantly lower in elderly participants than young participants in the thalamus, and frontal, temporal, occipital, and parietal cortices. In the human brain, we could observe the age-related decrease in the distribution of A1Rs.
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Assessment of safety, efficacy, and dosimetry of a novel 18-kDa translocator protein ligand, [ 11C]CB184, in healthy human volunteers. EJNMMI Res 2017; 7:26. [PMID: 28337723 PMCID: PMC5364125 DOI: 10.1186/s13550-017-0271-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/01/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND N,N-di-n-propyl-2-[2-(4-[11C]methoxyphenyl)-6,8-dichloroimidazol[1,2-a]pyridine-3-yl]acetamide ([11C]CB184) is a novel selective radioligand for the 18-kD translocator protein (TSPO), which is upregulated in activated microglia in the brain, and may be useful in positron emission tomography (PET). We examined the safety, radiation dosimetry, and initial brain imaging with [11C]CB184 in healthy human volunteers. RESULTS Dynamic [11C]CB184 PET scans (90 min) were performed in five healthy male subjects. During the scan, arterial blood was sampled at various time intervals, and the fraction of the parent compound in plasma was determined with high-performance liquid chromatography. No serious adverse events occurred in any of the subjects throughout the study period. [11C]CB184 was metabolized in the periphery: 36.7% ± 5.7% of the radioactivity in plasma was detected as the unchanged form after 60 min. The total distribution volume (V T) was estimated with a two-tissue compartment model. The V T of [11C]CB184 was highest in the thalamus (5.1 ± 0.4), followed by the cerebellar cortex (4.4 ± 0.2), and others. Although regional differences were small, the observed [11C]CB184 binding pattern was consistent with the TSPO distribution in the normal human brain. Radiation dosimetry was determined in three healthy male subjects using a serial whole-body PET scan acquired over 2 h after [11C]CB184 injection. [11C]CB184 PET demonstrated high uptake in the gallbladder at a later time (>60 min). In urine obtained approximately 100 min post-injection, 0.3% of the total injected radioactivity was recovered, indicating hepatobiliary excretion of radioactivity. The absorbed dose (μGy/MBq) was highest in the kidneys (21.0 ± 0.5) followed by the lungs (16.8 ± 2.7), spleen (16.6 ± 6.6), and pancreas (16.5 ± 2.2). The estimated effective dose for [11C]CB184 was 5.9 ± 0.6 μSv/MBq. CONCLUSIONS This initial evaluation indicated that [11C]CB184 is feasible for imaging of TSPO in the brain.
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Relationship between density of metabotropic glutamate receptors subtype 1 and asymmetrical parkinsonism in Parkinson’s disease – a ITMM PET study –. J Neurol Sci 2017. [DOI: 10.1016/j.jns.2017.08.2271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Changes in brain amyloid-β accumulation after donepezil administration. J Clin Neurosci 2017; 45:328-329. [PMID: 28864409 DOI: 10.1016/j.jocn.2017.08.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 08/10/2017] [Indexed: 11/24/2022]
Abstract
Recent studies using the mouse model of Alzheimer's disease (AD) have shown that donepezil administration reduces brain amyloid-β (Aβ) accumulation. This study investigated whether donepezil administration can reduce brain Aβ accumulation in human patients with AD. Ten patients with AD underwent two 11C-Pittsburgh Compound B positron emission tomography sessions approximately one year apart to measure brain Aβ accumulation before and after donepezil treatment. Volumes-of-interest were placed on Aβ-preferred regions, and the standardized uptake value ratio (SUVR) was calculated considering the cerebellum as a reference region. Three and seven patients received 10mg and 5mg of donepezil, respectively. SUVR was significantly higher in the second than in the first session (P=0.026). This study showed that one year of donepezil administration does not reduce brain Aβ accumulation in human patients with AD.
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Effects of a novel tungsten-impregnated rubber neck shield on the quality of cerebral images acquired using 15O-labeled gas. Radiol Phys Technol 2017; 10:422-430. [PMID: 28823084 DOI: 10.1007/s12194-017-0414-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 10/19/2022]
Abstract
The present study aimed to validate the effects of a novel tungsten-impregnated rubber neck shield on the quality of phantom and clinical 15O-labeled gas positron emission tomography (PET) images. Images were acquired in the presence or absence of a neck shield from a cylindrical phantom containing [15O]H2O (phantom study) and from three individuals using [15O]CO2, [15O]O2 and [15O]CO gas (clinical study). Data were acquired in three-dimensional (3D) mode using a Discovery PET/CT 710. Values for cerebral blood flow, cerebral blood volume, oxygen extraction fraction, and cerebral metabolic rate of oxygen with and without the neck shield were calculated from 15O-labeled gas images. Arterial radioactivity and count characteristics were evaluated in the phantom and clinical studies. The coefficient of variance (CV) for the phantom study and the standard deviation (SD) for functional images were also analyzed. The neck shield decreased the random count rates by 25-59% in the phantom and clinical studies. The noise equivalent count rate (NECR) increased by 44-66% in the phantom and clinical studies. Random count rates and NECR in [15O]CO2 images significantly differed with and without the neck shield. The improvement in visual and physical image quality with the neck shield was not observed in the phantom and clinical studies. The novel neck shield reduced random count rate and improved NECR in a 3D PET study using 15O-labeled gas. The image quality with the neck shield was similar to that without the neck shield.
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Effects of glucose, insulin, and insulin resistance on cerebral 18F-FDG distribution in cognitively normal older subjects. PLoS One 2017; 12:e0181400. [PMID: 28715453 PMCID: PMC5513548 DOI: 10.1371/journal.pone.0181400] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 07/02/2017] [Indexed: 12/21/2022] Open
Abstract
Background Increasing plasma glucose levels and insulin resistance can alter the distribution pattern of fluorine-18-labeled fluorodeoxyglucose (18F-FDG) in the brain and relatively reduce 18F-FDG uptake in Alzheimer's disease (AD)-related hypometabolic regions, leading to the appearance of an AD-like pattern. However, its relationship with plasma insulin levels is unclear. We aimed to compare the effects of plasma glucose levels, plasma insulin levels and insulin resistance on the appearance of the AD-like pattern in 18F-FDG images. Methods Fifty-nine cognitively normal older subjects (age = 75.7 ± 6.4 years) underwent 18F-FDG positron emission tomography along with measurement of plasma glucose and insulin levels. As an index of insulin resistance, the Homeostasis model assessment of Insulin Resistance (HOMA-IR) was calculated. Results Plasma glucose levels, plasma insulin levels, and HOMA-IR were 102.2 ± 8.1 mg/dL, 4.1 ± 1.9 μU/mL, and 1.0 ± 0.5, respectively. Whole-brain voxelwise analysis showed a negative correlation of 18F-FDG uptake with plasma glucose levels in the precuneus and lateral parietotemporal regions (cluster-corrected p < 0.05), and no correlation with plasma insulin levels or HOMA-IR. In the significant cluster, 18F-FDG uptake decreased by approximately 4–5% when plasma glucose levels increased by 20 mg/dL. In the precuneus region, volume-of-interest analysis confirmed a negative correlation of 18F-FDG uptake with plasma glucose levels (r = -0.376, p = 0.002), and no correlation with plasma insulin levels (r = 0.156, p = 0.12) or HOMA-IR (r = 0.096, p = 0.24). Conclusion This study suggests that, of the three parameters, plasma glucose levels have the greatest effect on the appearance of the AD-like pattern in 18F-FDG images.
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Effects of exercise on brain activity during walking in older adults: a randomized controlled trial. J Neuroeng Rehabil 2017; 14:50. [PMID: 28558817 PMCID: PMC5450147 DOI: 10.1186/s12984-017-0263-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 05/24/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Physical activity may preserve neuronal plasticity, increase synapse formation, and cause the release of hormonal factors that promote neurogenesis and neuronal function. Previous studies have reported enhanced neurocognitive function following exercise training. However, the specific cortical regions activated during exercise training remain largely undefined. In this study, we quantitatively and objectively evaluated the effects of exercise on brain activity during walking in healthy older adults. METHODS A total of 24 elderly women (75-83 years old) were randomly allocated to either an intervention group or a control group. Those in the intervention group attended 3 months of biweekly 90-min sessions focused on aerobic exercise, strength training, and physical therapy. We monitored changes in regional cerebral glucose metabolism during walking in both groups using positron emission tomography (PET) and [18F]fluorodeoxyglucose (FDG). RESULTS All subjects completed the 3-month experiment and the adherence to the exercise program was 100%. Compared with the control group, the intervention group showed a significantly greater step length in the right foot after 3 months of physical activity. The FDG-PET assessment revealed a significant post-intervention increase in regional glucose metabolism in the left posterior entorhinal cortex, left superior temporal gyrus, and right superior temporopolar area in the intervention group. Interestingly, the control group showed a relative increase in regional glucose metabolism in the left premotor and supplemental motor areas, left and right somatosensory association cortex, and right primary visual cortex after the 3-month period. We found no significant differences in FDG uptake between the intervention and control groups before vs. after the intervention. CONCLUSION Exercise training increased activity in specific brain regions, such as the precuneus and entorhinal cortices, which play an important role in episodic and spatial memory. Further investigation is required to confirm whether alterations in glucose metabolism within these regions during walking directly promote physical and cognitive performance. TRIAL REGISTRATION UMIN-CTR ( UMIN000021829 ). Retrospectively registered 10 April 2016.
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Adenosine A1receptors measured with11C-MPDX PET in early Parkinson's disease. Synapse 2017; 71. [DOI: 10.1002/syn.21979] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/02/2017] [Accepted: 04/10/2017] [Indexed: 01/16/2023]
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Noninvasive Evaluation of CBF and Perfusion Delay of Moyamoya Disease Using Arterial Spin-Labeling MRI with Multiple Postlabeling Delays: Comparison with 15O-Gas PET and DSC-MRI. AJNR Am J Neuroradiol 2017; 38:696-702. [PMID: 28209582 DOI: 10.3174/ajnr.a5068] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 11/09/2016] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND PURPOSE Arterial spin-labeling MR imaging with multiple postlabeling delays has a potential to evaluate various hemodynamic parameters. To clarify whether arterial spin-labeling MR imaging can identify CBF and perfusion delay in patients with Moyamoya disease, we compared arterial spin-labeling, DSC, and 15O-gas PET in terms of their ability to identify these parameters. MATERIALS AND METHODS Eighteen patients with Moyamoya disease (5 men, 13 women; ages, 21-55 years) were retrospectively analyzed. CBF values of pulsed continuous arterial spin-labeling using 2 postlabeling delays (short arterial spin-labeling, 1525 ms; delayed arterial spin-labeling, 2525 ms) were compared with CBF values measured by 15O-gas PET. All plots were divided into 2 groups by the cutoff of time-based parameters (the time of the maximum observed concentration, TTP, MTT, delay of MTT to cerebellum, and disease severity [symptomatic or not]). The ratio of 2 arterial spin-labeling CBFs (delayed arterial spin-labeling CBF to short arterial spin-labeling CBF) was compared with time-based parameters: time of the maximum observed concentration, TTP, and MTT. RESULTS The short arterial spin-labeling-CBF values were significantly correlated with the PET-CBF values (r = 0.63; P = .01). However, the short arterial spin-labeling-CBF value dropped in the regions with severe perfusion delay. The delayed arterial spin-labeling CBF overestimated PET-CBF regardless of the degree of perfusion delay. Delayed arterial spin-labeling CBF/short arterial spin-labeling CBF was well correlated with the time of the maximum observed concentration, TTP, and MTT (ρ = 0.71, 0.64, and 0.47, respectively). CONCLUSIONS Arterial spin-labeling using 2 postlabeling delays may detect PET-measured true CBF and perfusion delay in patients with Moyamoya disease. Provided its theoretic basis and limitations are considered, noninvasive arterial spin-labeling could be a useful alternative for evaluating the hemodynamics of Moyamoya disease.
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Age and gender effects of 11C-ITMM binding to metabotropic glutamate receptor type 1 in healthy human participants. Neurobiol Aging 2017; 55:72-77. [PMID: 28431287 DOI: 10.1016/j.neurobiolaging.2017.03.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 03/15/2017] [Accepted: 03/19/2017] [Indexed: 12/16/2022]
Abstract
We examined possible age- and gender-related changes in binding of the selective antagonist N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-4-11C-methoxy-N-methylbenzamide (11C-ITMM) to metabotropic glutamate receptor type 1 in healthy human brains. Dynamic 11C-ITMM positron emission tomography scans (90 min) with serial arterial blood sampling were performed in 15 young and 24 older healthy adult volunteers. The total distribution volume (VT) of several brain regions was estimated with 2-tissue compartment model analysis. The VTs of the cerebellar cortex, parietal cortex, putamen, amygdala, and hippocampus in older adult participants were significantly higher than in young participants. The age-related VT increase was only observed in male participants. Our data suggest that an age-dependent increase in metabotropic glutamate receptor type 1 availability in several brain regions may exist predominantly in males.
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Cerebral Functional Response during Eyelid Opening/Closing with Bell's Phenomenon and Volitional Vertical Eye Movements in Humans. TOHOKU J EXP MED 2017; 240:141-146. [PMID: 27725571 DOI: 10.1620/tjem.240.141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bell's phenomenon is a physiological phenomenon wherein the eye ball involuntarily rolls upward during eyelid closing. Although this phenomenon occurs in healthy individuals, the neural mechanism related to Bell's phenomenon has not yet been identified. We aimed to investigate the brain regions relevant to Bell's phenomenon and volitional eye movement using [15O] H2O and positron emission tomography (PET). We measured regional cerebral blood flow (rCBF) in 8 normal subjects under 3 conditions: at rest with eyes closed, during opening and closing of the eyelids in response to sound stimuli (lid opening/closing), and during vertical movement of the eyes with lids closed in response to sound stimuli (volitional eye movement). The supplementary motor area (SMA) proper, right superior temporal gyrus, right insular cortex and left angular gyrus were activated during lid opening/closing. The right frontal eye field (FEF), pre-SMA, left primary motor area, right angular gyrus, and SMA proper were activated during volitional eye movement. The SMA proper was active during both tasks, while the FEF and pre-SMA were active during volitional eye movement, but not during eyelid opening/closing. A comparison of activation during volitional eye movements and lid opening/closing tasks revealed a relative increase in rCBF in the FEF. There were no areas that are activated in relation to Bell's phenomenon. In conclusion, activation in the FEF mainly occurs during volitional eye movement. Since Bell's phenomenon is a reflexive eye movement, the FEF is scarcely concerned in Bell's phenomenon.
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Initial Evaluation of an Adenosine A2A Receptor Ligand, 11C-Preladenant, in Healthy Human Subjects. J Nucl Med 2017; 58:1464-1470. [DOI: 10.2967/jnumed.116.188474] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Accepted: 02/13/2017] [Indexed: 12/15/2022] Open
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The neural substrate of gait and executive function relationship in elderly women: A PET study. Geriatr Gerontol Int 2017; 17:1873-1880. [PMID: 28188956 DOI: 10.1111/ggi.12982] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/12/2016] [Accepted: 11/11/2016] [Indexed: 01/27/2023]
Abstract
AIM Understanding the relationship between age-related gait impairment, such as slow gait, and executive functioning in seniors may help identify individuals at higher risk of mobility decline, falls, and progression to dementia at earlier stages. We aim to identify brain regions concomitantly associated with poor gait and executive functioning in a cohort of well-functioning elderly women. METHODS In total, 149 well-functioning women aged 70.1 ± 6.2 years underwent FDG-PET to evaluate regional cerebral metabolic rates of glucose normalized in reference to cerebellar glucose metabolic value (normalized-rCMRglc) in 16 brain areas. We assessed gait speed, step length and cadence under usual and fast conditions. Executive function was assessed using Trail-Making-Tests (TMT) A and B. RESULTS Adjusted multiple regression analyses for potential covariates showed that TMT-B and ΔTMT (TMT B-A) were associated with gait speed and cadence at fast condition. Lower normalized-rCMRglc in the posterior cingulate and primary sensorimotor cortices were associated with longer TMT-B and ΔTMT times (i.e., lower executive function) as well as with slower gait speed and lower cadence at fast condition. Slower gait speed and lower cadence at fast condition were also associated with lower normalized-rCMRglc in the occipital and parietal cortices. There were no other significant associations. CONCLUSIONS In healthy elderly women without impending disability or cognitive impairment, reduced glucose metabolism in the posterior cingulate and primary sensorimotor cortices were associated with both lower gait performance and executive functioning. Our results suggest that gait control and executive functions might share the same neural substrate. Geriatr Gerontol Int 2017; 17: 1873-1880.
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Potential Therapeutic Applications of Adenosine A 2A Receptor Ligands and Opportunities for A 2A Receptor Imaging. Med Res Rev 2017; 38:5-56. [PMID: 28128443 DOI: 10.1002/med.21432] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/31/2016] [Accepted: 11/14/2016] [Indexed: 12/13/2022]
Abstract
Adenosine A2A receptors (A2A Rs) are highly expressed in the human striatum, and at lower densities in the cerebral cortex, the hippocampus, and cells of the immune system. Antagonists of these receptors are potentially useful for the treatment of motor fluctuations, epilepsy, postischemic brain damage, or cognitive impairment, and for the control of an immune checkpoint during immunotherapy of cancer. A2A R agonists may suppress transplant rejection and graft-versus-host disease; be used to treat inflammatory disorders such as asthma, inflammatory bowel disease, and rheumatoid arthritis; be locally applied to promote wound healing and be employed in a strategy for transient opening of the blood-brain barrier (BBB) so that therapeutic drugs and monoclonal antibodies can enter the brain. Increasing A2A R signaling in adipose tissue is also a potential strategy to combat obesity. Several radioligands for positron emission tomography (PET) imaging of A2A Rs have been developed in recent years. This review article presents a critical overview of the potential therapeutic applications of A2A R ligands, the use of A2A R imaging in drug development, and opportunities and limitations of PET imaging in future research.
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Comparison of imaging using 11C-ITMM and 18F-FDG for the detection of cerebellar ataxia. J Neurol Sci 2017; 375:97-102. [PMID: 28320199 DOI: 10.1016/j.jns.2017.01.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 10/20/2022]
Abstract
Objective Newly developed methods for imaging type 1 metabotropic glutamate receptor (mGluR1) have the potential use for estimating cerebellar function. We aimed to compare mGluR1 imaging using N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-4-11C-methoxy-N-methylbenzamide (11C-ITMM) with the existing marker, fluorine-18-labeled fluorodeoxyglucose (18F-FDG) imaging, in the cerebellum. METHODS Fourteen subjects consisting of 12 patients with cerebellar ataxia and two healthy subjects underwent 11C-ITMM and 18F-FDG positron emission tomography. The degree of ataxia was scored with the Scale for the Assessment and Rating of Ataxia (SARA). Volumes-of-interest were placed on the anterior and posterior lobes and vermis. The binding potential (BPND) was calculated to estimate mGluR1 availability using the white matter as a reference region. 18F-FDG uptake was normalized using the white matter (FUwm). RESULTS There were significant positive correlations between the BPND and FUwm values in the anterior lobe (r=0.83, P<0.001), posterior lobe (r=0.69, P=0.009), and vermis (r=0.58, P=0.042). Regarding the relationship of SARA scores with the BPND and FUwm values, a significant negative correlation was found only in the anterior lobe between the SARA scores and BPND values (r=-0.64, P=0.029). CONCLUSION This study showed that mGluR1 imaging was comparable to 18F-FDG imaging in the cerebellum. However, mGluR1 imaging was more strongly associated with the SARA scores than 18F-FDG imaging was, suggesting that mGluR1 imaging can be a more specific technique than 18F-FDG imaging for evaluating cerebellar ataxia.
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Central μ-Opioidergic System Activation Evoked by Heavy and Severe-Intensity Cycling Exercise in Humans: a Pilot Study Using Positron Emission Tomography with 11C-Carfentanil. Int J Sports Med 2017; 38:19-26. [PMID: 28073122 DOI: 10.1055/s-0042-114779] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The central opioid receptor system likely contributes to the mechanism underlying the changes in affect elicited by exercise. Our aim was to use positron emission tomography (PET) to test whether exercise intensity influences activation of the μ-opioid receptor system in the brain, and whether changes in opioid receptor activation correlate with exercise-induced changes in affect. 7 healthy young male subjects (23±2 years) performed 20-min constant-load cycling exercises at heavy (ExH) and severe-intensity (ExS), and PET was performed using [11C]carfentanil as a tracer before and after each exercise. Exercise elicited the μ-opioidergic system activation in the large areas of the limbic system, particularly in the insular cortex, and cerebellum. Of note, deactivation of the μ-opioidergic system in the pituitary gland was identified as a specific finding in ExS, which evoked a distinctive sensation of fatigue. Within these brain areas, μ-opioid receptor activation correlated positively with increased positive affect (R2=0.67-0.95) in ExH and negative affect (R2=0.63-0.77) in ExS. These findings suggest that central μ-opioidergic neurotransmission evoked by continuous exercise is discriminated by work intensity. Notably, we also observed a possible contribution of the central μ-opioidergic system to the development of the sensation of fatigue during exhaustive exercise.
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In Vivo Evaluation of 11C-Preladenant for PET Imaging of Adenosine A 2A Receptors in the Conscious Monkey. J Nucl Med 2017; 58:762-767. [PMID: 28062599 DOI: 10.2967/jnumed.116.182410] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 11/10/2016] [Indexed: 12/22/2022] Open
Abstract
11C-preladenant was developed as a novel PET ligand for the adenosine A2A receptors (A2ARs). The present study aimed to evaluate the suitability of 11C-preladenant PET for the quantification of striatal A2ARs and the assessment of A2AR occupancy in the conscious monkey brain. Methods:11C-preladenant was intravenously injected into conscious monkeys (n = 4, 18 PET scans), and a 91-min dynamic scan was started. Arterial blood samples in combination with metabolite analysis were obtained during the scan to provide the input function for kinetic modeling. The distribution volume (VT) was obtained by kinetic modeling with a 2-tissue-compartment model. The simplified reference tissue model (SRTM) with selected reference regions (cerebellum, cingulate, parietal cortex, and occipital cortex) was tested to estimate the binding potential (BPND) in A2AR-rich regions. BPND obtained from the SRTM was compared with distribution volume ratio (DVR)-1. The effects of blood volume, blood delay, and scan duration on BPND and DVR-1 were investigated. VT and BPND were also obtained after preblocking with unlabeled preladenant (1 mg/kg), A2AR-selective KW-6002 (0.5-1 mg/kg), and nonselective adenosine receptor antagonist caffeine (2.5-10 mg/kg). A2AR occupancy was studied with caffeine blockade. Results: Regional uptake of 11C-preladenant was consistent with the distribution of A2ARs in the monkey brain, with the highest uptake in the putamen, followed by the caudate, and the lowest uptake in the cerebellum. Tracer kinetics were well described by the 2-tissue-compartment model with a lower constraint on k4 to stabilize fits. The highest VT was observed in A2AR-rich regions (∼5.8-7.4) and lowest value in the cerebellum (∼1.3). BPND values estimated from the SRTM with different scan durations were comparable and were in agreement with DVR-1 (∼4.3-5.3 in A2AR-rich regions). Preladenant preinjection decreased the tracer uptake in A2AR-rich regions to the level of the reference regions. Caffeine pretreatment reduced the tracer uptake in the striatum in a dose-dependent manner. Conclusion:11C-preladenant PET is suitable for noninvasive quantification of A2ARs and assessment of A2AR occupancy in A2AR-rich regions in the monkey brain. SRTM using the cerebellum as the reference tissue is the applicable model for A2AR quantification.
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Long-term cilostazol administration ameliorates memory decline in senescence-accelerated mouse prone 8 (SAMP8) through a dual effect on cAMP and blood-brain barrier. Neuropharmacology 2016; 116:247-259. [PMID: 27979612 DOI: 10.1016/j.neuropharm.2016.12.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/18/2016] [Accepted: 12/09/2016] [Indexed: 12/12/2022]
Abstract
Phosphodiesterases (PDEs), which hydrolyze and inactivate 3', 5'-cyclic adenosine monophosphate (cAMP) and 3', 5'-cyclic guanosine monophosphate (cGMP), play an important role in synaptic plasticity that underlies memory. Recently, several PDE inhibitors were assessed for their possible therapeutic efficacy in treating cognitive disorders. Here, we examined how cilostazol, a selective PDE3 inhibitor, affects brain functions in senescence-accelerated mouse prone 8 (SAMP8), an animal model of age-related cognitive impairment. Long-term administration of cilostazol restored the impaired context-dependent conditioned fear memory of SAMP8 to match that in normal aging control substrain SAMR1. Cilostazol also increased the number of cells containing phosphorylated cAMP-responsive element binding protein (CREB), a downstream component of the cAMP pathway. Finally, cilostazol improves blood-brain barrier (BBB) integrity, demonstrated by reduced extravasation of 2-deoxy-2-18F-fluoro-d-glucose and Evans Blue dye in the brains of SAMP8. This improvement in BBB integrity was associated with an increased amount of zona occludens protein 1 (ZO-1) and occludin proteins, components of tight junctions integral to the BBB. The results suggest that long-term administration of cilostazol exerts its beneficial effects on age-related cognitive impairment through a dual mechanism: by enhancing the cAMP system in the brain and by maintaining or improving BBB integrity.
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A single-institution study examining cutaneous and non-cutaneous melanomas treated with nivolumab. J Eur Acad Dermatol Venereol 2016; 30:e227-e229. [DOI: 10.1111/jdv.13561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Determination of radionuclides and radiochemical impurities produced by in-house cyclotron irradiation and subsequent radiosynthesis of PET tracers. Ann Nucl Med 2016; 31:84-92. [PMID: 27744544 PMCID: PMC5233741 DOI: 10.1007/s12149-016-1134-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/10/2016] [Indexed: 11/27/2022]
Abstract
Objective To elucidate the radionuclides and radiochemical impurities included in radiosynthesis processes of positron emission tomography (PET) tracers. Methods Target materials and PET tracers were produced using a cyclotron/synthesis system from Sumitomo Heavy Industry. Positron and γ-ray emitting radionuclides were quantified by measuring radioactivity decay and using the high-purity Ge detector, respectively. Radiochemical species in gaseous and aqueous target materials were analyzed by gas and ion chromatography, respectively. Results Target materials had considerable levels of several positron emitters in addition to the positron of interest, and in the case of aqueous target materials extremely low levels of many γ-emitters. Five 11C-, 15O-, or 18F-labeled tracers produced from gaseous materials via chemical reactions had no radionuclidic impurities, whereas 18F-FDG, 18F-NaF, and 13N-NH3 produced from aqueous materials had several γ-emitters as well as impure positron emitters. 15O-Labeled CO2, O2, and CO had a radionuclidic impurity 13N-N2 (0.5–0.7 %). Conclusions Target materials had several positron emitters other than the positron of interest, and extremely low level γ-emitters in the case of aqueous materials. PET tracers produced from gaseous materials except for 15O-labeled gases had no impure radionuclides, whereas those derived from aqueous materials contained acceptable levels of impure positron emitters and extremely low levels of several γ-emitters. Electronic supplementary material The online version of this article (doi:10.1007/s12149-016-1134-3) contains supplementary material, which is available to authorized users.
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Abstract
PURPOSE Sigma-1 receptor ligands modulate the release of several neurotransmitters and intracellular calcium signaling. We examined the binding of a radiolabeled sigma-1 agonist in the aging rat brain with positron emission tomography (PET). PROCEDURES Time-dependent uptake of [(11)C]SA4503 was measured in the brain of young (1.5 to 3 months) and aged (18 to 32 months) Wistar Hannover rats, and tracer-kinetic models were fitted to this data, using metabolite-corrected plasma radioactivity as input function. RESULTS In aged animals, the injected probe was less rapidly metabolized and cleared. Logan graphical analysis and a 2-tissue compartment model (2-TCM) fit indicated changes of total distribution volume (V T) and binding potential (BP ND) of the tracer. BP ND was reduced particularly in the (hypo)thalamus, pons, and medulla. CONCLUSIONS Some areas showed reductions of ligand binding with aging whereas binding in other areas (cortex) was not significantly affected.
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Preclinical and first-in-man studies of [(11)C]CB184 for imaging the 18-kDa translocator protein by positron emission tomography. Ann Nucl Med 2016; 30:534-43. [PMID: 27329083 DOI: 10.1007/s12149-016-1094-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/30/2016] [Indexed: 01/17/2023]
Abstract
OBJECTIVE We performed preclinical and first-in-man clinical positron emission tomography (PET) studies in human brain using N,N-di-n-propyl-2-[2-(4-[(11)C]methoxyphenyl)-6,8-dichloroimidazol[1,2-a]pyridine-3-yl]acetamide ([(11)C]CB184) to image the 18-kDa translocator protein (TSPO), which is overexpressed in activated microglia in neuroinflammatory conditions. METHODS In vitro selectivity of CB184 was characterized. The radiation absorbed dose by [(11)C]CB184 in humans was calculated from murine distribution data. Acute toxicity of CB184 hydrochloride in rats at a dose of 5.81 mg/kg body weight, which is >10,000-fold higher than the clinical equivalent dose of [(11)C]CB184, was evaluated. Acute toxicity of [(11)C]CB184 injection of a 400-fold dose to administer a postulated dose of 740 MBq [(11)C]CB184 was also evaluated after the decay-out of (11)C. The mutagenicity of CB184 was studied with a reverse mutation test (Ames test). The pharmacological effect of CB184 injection in mice was studied with an open field test. The first PET imaging of TSPO with [(11)C]CB184 in a normal human volunteer was performed. RESULTS A suitable preparation method for [(11)C]CB184 injection was established. CB184 showed low activity in a 28-standard receptor binding profile. The radiation absorbed dose by [(11)C]CB184 in humans was sufficiently low for clinical use, and no acute toxicity of CB184 or [(11)C]CB184 injection was found. No mutagenicity or apparent effect on locomotor activity or anxiety status was observed for CB184. We safely performed brain imaging with PET following administration of [(11)C]CB184 in a normal human volunteer. A 90-min dynamic scan showed rapid initial uptake of radioactivity in the brain followed by prompt clearance. [(11)C]CB184 was homogeneously distributed in the gray matter. The total distribution volume of [(11)C]CB184 was highest in the thalamus followed by the cerebellar cortex and elsewhere. Although regional differences were small, the observed [(11)C]CB184 binding pattern was consistent with the TSPO distribution in normal human brain. Peripherally, [(11)C]CB184 was metabolized in humans: 30 % of the radioactivity in plasma was detected as the unchanged form after 60 min. CONCLUSIONS [(11)C]CB184 is suitable for imaging TSPO in human brain and provides an acceptable radiation dose. Pharmacological safety was noted at the dose required for PET imaging.
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Optimization of the alkyl side chain length of fluorine-18-labeled 7α-alkyl-fluoroestradiol. Nucl Med Biol 2016; 43:512-9. [PMID: 27289329 DOI: 10.1016/j.nucmedbio.2016.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 05/16/2016] [Accepted: 05/19/2016] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Several lines of evidence suggest that 7α-substituted estradiol derivatives bind to the estrogen receptor (ER). In line with this hypothesis, we designed and synthesized (18)F-labeled 7α-fluoroalkylestradiol (Cn-7α-[(18)F]FES) derivatives as molecular probes for visualizing ERs. Previously, we successfully synthesized 7α-(3-[(18)F]fluoropropyl)estradiol (C3-7α-[(18)F]FES) and showed promising results for quantification of ER density in vivo, although extensive metabolism was observed in rodents. Therefore, optimization of the alkyl side chain length is needed to obtain suitable radioligands based on Cn-7α-substituted estradiol pharmacophores. METHODS We synthesized fluoromethyl (23; C1-7α-[(18)F]FES) to fluorohexyl (26; C6-7α-[(18)F]FES) derivatives, except fluoropropyl (C3-7α-[(18)F]FES) and fluoropentyl derivatives (C5-7α-[(18)F]FES), which have been previously synthesized. In vitro binding to the α-subtype (ERα) isoform of ERs and in vivo biodistribution studies in mature female mice were carried out. RESULTS The in vitro IC50 value of Cn-7α-FES tended to gradually decrease depending on the alkyl side chain length. C1-7α-[(18)F]FES (23) showed the highest uptake in ER-rich tissues such as the uterus. Uterus uptake also gradually decreased depending on the alkyl side chain length. As a result, in vivo uterus uptake reflected the in vitro ERα affinity of each compound. Bone uptake, which indicates de-fluorination, was marked in 7α-(2-[(18)F]fluoroethyl)estradiol (C2-7α-[(18)F]FES) (24) and 7α-(4-[(18)F]fluorobutyl)estradiol (C4-7α-[(18)F]FES) (25) derivatives. However, C1-7α-[(18)F]FES (23) and C6-7α-[(18)F]FES (26) showed limited uptake in bone. As a result, in vivo bone uptake (de-fluorination) showed a bell-shaped pattern, depending on the alkyl side chain length. C1-7α-[(18)F]FES (23) showed the same levels of uptake in uterus and bone compared with those of 16α-[(18)F]fluoro-17β-estradiol. CONCLUSIONS The optimal alkyl side chain length of (18)F-labeled 7α-fluoroalkylestradiol was the shortest: C1-7α-[(18)F]FES. Our results indicate that shorter chain lengths within the 4-Å ligand binding cavities of ERα are suitable for 7α-fluoroalkylestradiol derivatives.
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Alteration of the regional cerebral glucose metabolism in healthy subjects by glucose loading. Hum Brain Mapp 2016; 37:2823-32. [PMID: 27061859 DOI: 10.1002/hbm.23210] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/22/2016] [Accepted: 03/28/2016] [Indexed: 01/03/2023] Open
Abstract
High plasma glucose (PG) levels can reduce fluorine-18-labeled fluorodeoxyglucose ((18) F-FDG) uptake, especially in the Alzheimer's disease (AD)-related regions. This fact is supported by studies showing that the resting-state activity in diabetes can be altered in the default mode network (DMN)-related regions, which considerably overlap with the AD-related regions. In order to expand the current knowledge, we aimed to investigate the relationship between increasing PG levels and the regional cerebral metabolic rates for glucose (CMRglc ) as a direct index of brain activity. We performed dynamic (18) F-FDG positron emission tomography with arterial blood sampling once each in the fasting and glucose-loading conditions on 12 young, healthy volunteers without cognitive impairment or insulin resistance. The absolute CMRglc values were calculated for the volume-of-interest (VOI) analysis, and normalized CMRglc maps were generated for the voxelwise analysis. The normalized measurement is known to have smaller intersubject variability than the absolute measurement, and may, thus, lead to greater statistical power. In VOI analysis, no regional difference in the CMRglc was found between the two conditions. In exploratory voxelwise analysis, however, significant clusters were identified in the precuneus, posterior cingulate, lateral parietotemporal, and medial prefrontal regions where the CMRglc decreased upon glucose loading (P < 0.05, corrected). These regions include the representative components of both the DMN and AD pathology. Taken together with the previous knowledge on the relationships between the DMN, AD, and diabetes, it may be inferred that glucose loading induces hypometabolism in the AD-related and DMN-related regions. Hum Brain Mapp 37:2823-2832, 2016. © 2016 Wiley Periodicals, Inc.
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Haemaphysalis longicornis tick bites are a possible cause of red meat allergy in Japan. Allergy 2016; 71:421-5. [PMID: 26551325 DOI: 10.1111/all.12804] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2015] [Indexed: 11/26/2022]
Abstract
Recent studies revealed that Amblyomma or Ixodes tick bites may cause red meat allergy, in which galactose-α-1,3-galactose (α-Gal) is a major IgE-binding epitope. The incidence of red meat allergy is high in Shimane Prefecture, as is tick-transmitted Japanese spotted fever. Therefore, we speculated that tick bites may cause these meat allergies. The carbohydrate α-Gal was detected in the salivary gland protein of Haemaphysalis longicornis (H. longicornis), the vector for Japanese spotted fever, by immunoblotting using anti-α-Gal antibody. H. longicornis salivary gland protein-specific IgE was detected in the sera of 24 of 30 patients with red meat allergies. Sensitization to tick salivary gland protein containing α-Gal is possibly a major etiology of red meat allergy; the carbohydrate plays a crucial role in its allergenicity. These results further indicate that the α-Gal epitope is present not only in Amblyomma or Ixodes, but also in Haemaphysalis.
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Radiosynthesis and preliminary biological evaluation of a new18F-labeled triethylene glycol derivative of triphenylphosphonium. J Labelled Comp Radiopharm 2016; 59:117-23. [DOI: 10.1002/jlcr.3379] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 01/02/2016] [Accepted: 01/14/2016] [Indexed: 02/01/2023]
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Lymphopenia can be a useful biomarker of adverse events related to vemurafenib. J Eur Acad Dermatol Venereol 2016; 31:e24-e26. [PMID: 26810349 DOI: 10.1111/jdv.13591] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Synthesis and Characterization of ¹⁸F-Interleukin-8 Using a Cell-Free Translation System and 4-¹⁸F-Fluoro-L-Proline. J Nucl Med 2016; 57:634-9. [PMID: 26742712 DOI: 10.2967/jnumed.115.162602] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 12/01/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Macromolecules such as proteins are attracting increasing interest for molecular imaging. We previously proposed a novel strategy for preparing macromolecules labeled with a PET radionuclide, (11)C, using a cell-free translation system with (11)C-methionine. However, macromolecules tend to exhibit slower kinetics, thus requiring a longer scanning time. Here, we expand our strategy using (18)F, which has a longer half-life, with the cell-free translation system with 4-(18)F-fluoro-L-proline ((18)F-FPro). We evaluated (18)F-interleukin-8 ((18)F-IL-8) produced by this method in vitro and in vivo to provide a proof of concept of our strategy. METHODS We tested some fluorinated amino acids to be incorporated into a protein. Trans-(18)F-FPro was radiolabeled from the corresponding precursor. (18)F-IL-8 was produced using the cell-free translation system with trans-(18)F-FPro instead of natural L-proline with incubation at 37°C for 120 min. An in vitro binding assay of (18)F-IL-8 was performed using IL-8 receptor-expressing cells. After intravenous administration of (18)F-IL-8, in vivo PET imaging of IL-8 receptor-expressing xenograft-bearing mice was performed using a small-animal PET system. RESULTS FPro was identified as an amino acid incorporated into the protein. (18)F-IL-8 was successfully prepared using the cell-free translation system and trans-(18)F-FPro with the radiochemical yield of 1.5% (decay-corrected) based on trans-(18)F-FPro. In vitro binding assays of (18)F-IL-8 demonstrated its binding to IL-8 receptor. In vivo PET imaging demonstrated that (18)F-IL-8 clearly accumulated in IL-8 receptor-expressing xenografts in mice, unlike trans-(18)F-FPro. CONCLUSION (18)F-IL-8 produced by this method binds to IL-8 receptors in vitro, and (18)F-IL-8 PET clearly visualizes its target receptor-expressing xenograft in vivo. Therefore, this technique might be useful for labeling macromolecules and performing preclinical evaluations of proteins of interest in vitro and in vivo.
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( R )-[ 11 C]Emopamil as a novel tracer for imaging enhanced P-glycoprotein function. Nucl Med Biol 2016; 43:52-62. [DOI: 10.1016/j.nucmedbio.2015.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 08/31/2015] [Accepted: 09/03/2015] [Indexed: 11/28/2022]
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Amyloid β accumulation assessed with ¹¹C-Pittsburgh compound B PET and postmortem neuropathology. Curr Alzheimer Res 2015; 12:278-86. [PMID: 25731622 DOI: 10.2174/1567205012666150302155930] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 02/22/2015] [Indexed: 11/22/2022]
Abstract
¹¹C-Pittsburgh compound B (PiB) uptake in PET images is frequently used to analyze β amyloid (Aβ) deposition in living individuals, but its correlation with histologically determined Aβ has not been examined. Six individuals with dementia underwent PiB-PET imaging, and their brains were analyzed neuropathologically (mean interval between imaging and death: 816 days; PiB positive:negative, 3:3; male:female, 3:3; mean age: 84.0 years). PiB uptake (reported as standardized uptake value ratio [SUVR]) was analyzed in 11 cortical regions and 10 subcortical grey matter areas and compared with the Aβ load (% area [the percentage of total area positive for Aβ] and number of neuritic plaques) seen with immunohistochemical staining with an anti-Aβ 11-28 antibody. Two PiB-positive subjects had abundant neuritic plaques and were diagnosed with Alzheimer’s disease (AD). SUVR and % area were strongly correlated in the cortical regions of these subjects (subject 1: r = 0.65, p = 0.03; subject 2: r = 0.80, p = 0.003). The other PiBpositive subject (subject 3) showed focal PiB uptake. In subject 3 and the 3 PiB-negative subjects (subjects 4-6), there was no correlation between regional SUVR and % area or neuritic plaques. PiB uptake was not correlated with Aβ deposition in subcortical regions. High PiB positivity in the cerebral cortex suggests the presence of substantial Aβ deposition and neuritic plaques associated with the pathologic changes of AD. Our results suggest that high cortical SUVR is a reliable marker of AD. Subcortical PiB positivity must be interpreted more carefully.
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NIMG-55USEFULNESS OF 11C-METHIONINE POSITRON EMISSION TOMOGRAPHY FOR THE MONITORING OF TREATMENT RESPONSE AND RECURRENCE IN PATIENT WITH MALIGNANT GLIOMA ON BEVACIZUMAB THERAPY: A CASE REPORT. Neuro Oncol 2015. [DOI: 10.1093/neuonc/nov225.55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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NIMG-65EVALUATION OF THE TREATMENT RESPONSE OF MALIGNANT GLIOMA ON BEVACIZUMAB THERAPY USING 11C-METHIONINE POSITRON EMISSION TOMOGRAPHY. Neuro Oncol 2015. [DOI: 10.1093/neuonc/nov225.65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Potential applications for sigma receptor ligands in cancer diagnosis and therapy. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1848:2703-14. [PMID: 25173780 DOI: 10.1016/j.bbamem.2014.08.022] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/04/2014] [Accepted: 08/19/2014] [Indexed: 01/03/2023]
Abstract
Sigma receptors (sigma-1 and sigma-2) represent two independent classes of proteins. Their endogenous ligands may include the hallucinogen N,N-dimethyltryptamine (DMT) and sphingolipid-derived amines which interact with sigma-1 receptors, besides steroid hormones (e.g., progesterone) which bind to both sigma receptor subpopulations. The sigma-1 receptor is a ligand-regulated molecular chaperone with various ion channels and G-protein-coupled membrane receptors as clients. The sigma-2 receptor was identified as the progesterone receptor membrane component 1 (PGRMC1). Although sigma receptors are over-expressed in tumors and up-regulated in rapidly dividing normal tissue, their ligands induce significant cell death only in tumor tissue. Sigma ligands may therefore be used to selectively eradicate tumors. Multiple mechanisms appear to underlie cell killing after administration of sigma ligands, and the signaling pathways are dependent both on the type of ligand and the type of tumor cell. Recent evidence suggests that the sigma-2 receptor is a potential tumor and serum biomarker for human lung cancer and an important target for inhibiting tumor invasion and cancer progression. Current radiochemical efforts are focused on the development of subtype-selective radioligands for positron emission tomography (PET) imaging. Right now, the mostpromising tracers are [18F]fluspidine and [18F]FTC-146 for sigma-1 receptors and [11C]RHM-1 and [18F]ISO-1 for the sigma-2 subtype. Nanoparticles coupled to sigma ligands have shown considerable potential for targeted delivery of antitumor drugs in animal models of cancer, but clinical studies exploring this strategy in cancer patients have not yet been reported. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Individual time course of pre- and postsynaptic PET imaging may improve differential diagnosis of Parkinson's disease and multiple system atrophy: a case report. BMC Res Notes 2015; 8:496. [PMID: 26419749 PMCID: PMC4589095 DOI: 10.1186/s13104-015-1522-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 09/21/2015] [Indexed: 11/26/2022] Open
Abstract
Background Many in vivo studies have shown a difference in pre- and/or postsynaptic imaging between Parkinson’s disease and multiple system atrophy; however, time course differences in pre- and postsynaptic imaging between Parkinson’s disease and multiple system atrophy have not been rigorously investigated. Case presentation We report serial positron emission tomography images of both dopamine transporters and dopamine D2 receptors, obtained from a Japanese patient with Parkinson’s disease who underwent positron emission tomography scanning at ages 71, 72, 74, and 75 years, and another Japanese patient with multiple system atrophy who underwent positron emission tomography scanning at ages 65, 66, and 67 years. Volumes-of-interest were placed on the striatal subregions. The percentage decreases between the first and last images showed that dopamine transporter availability decreased with disease progression in both patients, but that dopamine D2 receptor availability decreased only in the patient with multiple system atrophy. A partial correlation analysis between dopamine transporter and dopamine D2 receptor availability, controlling for the effects of striatal subregional differences, revealed a positive correlation in the patient with multiple system atrophy (r = 0.893, P = 0.0002), but no significant correlation in the patient with Parkinson’s disease (r = −0.036, P = 0.89). Conclusions The time course of pre- and postsynaptic imaging can be considerably different between Parkinson’s disease and multiple system atrophy, and may be useful in improving the accuracy of discrimination between Parkinson’s disease and multiple system atrophy.
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Severe rash associated with vemurafenib administration following nivolumab therapy. J Eur Acad Dermatol Venereol 2015; 30:e84-e86. [PMID: 26372833 DOI: 10.1111/jdv.13331] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Quantitative kinetic analysis of PET amyloid imaging agents [11C]BF227 and [18F]FACT in human brain. Nucl Med Biol 2015; 42:734-44. [DOI: 10.1016/j.nucmedbio.2015.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/07/2015] [Accepted: 05/01/2015] [Indexed: 11/30/2022]
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Reduced uptake of 18F-FDG and 15O-H2O in Alzheimer's disease-related regions after glucose loading. J Cereb Blood Flow Metab 2015; 35:1380-5. [PMID: 26058692 PMCID: PMC4527997 DOI: 10.1038/jcbfm.2015.127] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/14/2015] [Accepted: 05/18/2015] [Indexed: 11/09/2022]
Abstract
Increased plasma glucose levels are known to reduce fluorine-18-labeled fluorodeoxyglucose ((18)F-FDG) uptake in Alzheimer's disease (AD)-related regions, resulting in the appearance of an AD-like pattern. However, the relationships of its appearance with cerebral blood flow and insulin levels are uncertain. We performed (18)F-FDG and oxygen-15-labeled water ((15)O-H2O) positron emission tomography in the fasting and glucose-loading conditions on nine young healthy volunteers with no cognitive impairments. Measurement of plasma glucose and insulin levels confirmed that all subjects were free of insulin resistance, and that glucose loading significantly increased plasma glucose and insulin levels. Fluorine-18-labeled fluorodeoxyglucose and (15)O-H2O images were compared between the two conditions, focusing on AD-related regions: precuneus/posterior cingulate (PP), lateral parietal cortex (LPC), and frontal cortex (FC). Volume-of-interest analyses showed significantly lower uptake of both (18)F-FDG and (15)O-H2O in PP, LPC, and FC after glucose loading (P<0.05). Whole-brain voxel-wise analyses also revealed the PP, LPC, and FC areas where uptake of both (18)F-FDG and (15)O-H2O decreased (P<0.05, familywise error rate-corrected). We concluded that increased plasma glucose and insulin levels can cause the appearance of the AD-like pattern in both (18)F-FDG and (15)O-H2O images, and this phenomenon can occur even in subjects without insulin resistance.
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Alzheimer's disease-like pattern of (18)F-FDG uptake during a hyperglycemic state and negative (11)C-PiB binding in a patient with mild cognitive impairment. J Alzheimers Dis 2015; 42:385-9. [PMID: 24898648 DOI: 10.3233/jad-140639] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Increased plasma glucose levels can cause the regional reduction of fluorine-18-labeled fluorodeoxyglucose (18F-FDG) uptake in the posterior cingulate, precuneus, and/or temporoparietal cortices as an Alzheimer's disease (AD)-like pattern. However, the association of such an AD-like pattern of cerebral 18F-FDG uptake with AD pathophysiology is unknown. We report a case of a 70-year-old patient with mild cognitive impairment, and show that the AD-like pattern of cerebral 18F-FDG uptake during a hyperglycemic state could be reversible and is not associated with amyloid-β accumulation. Our case concludes that the AD-like pattern is dependent on the plasma glucose level and independent of AD pathophysiology.
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P4‐096: Secondary Alzheimer's disease: Characteristics of Alzheimer's disease preceded by non‐alzheimer's pathology. Alzheimers Dement 2015. [DOI: 10.1016/j.jalz.2015.06.1801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Cerebral glucose metabolism in the striate cortex positively correlates with fractional anisotropy values of the optic radiation in patients with glaucoma. Clin Exp Ophthalmol 2015; 43:711-9. [PMID: 25904022 DOI: 10.1111/ceo.12543] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 04/12/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND It has recently become clear that glaucoma is not only an ocular disease, but involves central visual pathways as well. The purpose of this study was to examine functional and structural alterations in the brains of glaucoma patients. DESIGN Case-control study in a hospital. PARTICIPANTS A total of 32 glaucoma patients and 19 healthy controls. METHODS All participants underwent positron emission tomography with (18)F-fluorodeoxyglucose, diffusion-tensor magnetic resonance imaging, and the 30-2 program of the Humphrey Visual Field Analyzer. MAIN OUTCOME MEASURES Fractional anisotropy values of the optic radiation were compared between the two groups by defining regions of interests. Cerebral glucose metabolism was compared using statistical parametric mapping software. The correlation coefficients were calculated between the average of the total deviation of hemivisual fields of both eyes, fractional anisotropy values of the contralateral optic radiation and glucose metabolism in the contralateral striate cortex. RESULTS Fractional anisotropy values in the bilateral optic radiations were significantly lower in patients with glaucoma. A significant glucose hypometabolism in the bilateral striate cortex was also observed in the glaucoma group. Regression analyses for glaucoma patients demonstrated that the average of the total deviation of hemivisual fields significantly correlated with both fractional anisotropy value of the contralateral optic radiation and glucose metabolism in the contralateral striate cortex. Moreover, there were significant correlations between fractional anisotropy values of the optic radiation and ipsilateral striatal glucose metabolism. CONCLUSION We observed structural alterations in the bilateral optic radiations and glucose hypometabolism in the bilateral striate cortex of glaucoma patients.
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Cutamesine Overcomes REM Sleep Deprivation-Induced Memory Loss: Relationship to Sigma-1 Receptor Occupancy. Mol Imaging Biol 2015; 17:364-72. [PMID: 25449772 DOI: 10.1007/s11307-014-0808-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE Rapid eye movement (REM) sleep deprivation (SD) decreases cerebral sigma-1 receptor expression and causes cognitive deficits. Sigma-1 agonists are cognitive enhancers. Here, we investigate the effect of cutamesine treatment in the REM SD model. PROCEDURES Sigma-1 receptor occupancy (RO) in the rat brain by cutamesine was determined using 1-[2-(3,4-dimethoxyphenethyl)]-4-(3-phenylpropyl)piperazine ([(11)C]SA4503) and positron emission tomography (PET), and tissue cutamesine levels were measured by ultra performance liquid chromatography (UPLC)-MS. RO was calculated from a Cunningham-Lassen plot, based on the total distribution volume of [(11)C]SA4503 determined by Logan graphical analysis. Cognitive performance was assessed using the passive avoidance (PA) test. RESULTS Cutamesine at a dose of 1.0 mg/kg reversed REM SD-induced cognitive deficit and occupied 92 % of the sigma-1 receptor population. A lower dose (0.3 mg/kg) occupied 88 % of the receptors but did not significantly improve cognition. CONCLUSION The anti-amnesic effect of cutamesine in this animal model may be related to longer exposure at a higher dose and/or drug binding to secondary targets.
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Abstract
PURPOSE Sigma-1 receptors are involved in learning and memory processes. We assessed sigma-1 receptor expression and memory function in two animal models of cognitive impairment. PROCEDURES Male Wistar-Hannover rats were either lesioned by unilateral injection of N-methyl-D-aspartic acid in the nucleus basalis, or deprived of rapid eye movement sleep for 48 h, using the modified multiple platform method. Sigma-1 receptor expression was examined with the positron emission tomography radiotracer [(11)C]SA4503, immunohistochemistry, and Western blotting. RESULTS Cortical tracer uptake after 1 week was not significantly affected by lesioning. Immunohistochemistry revealed moderate increases of sigma-1 receptors at bregma level -2.8, in parietal cortex layer V of the lesioned hemisphere. Sleep deprivation lowered passive avoidance test scores and reduced [(11)C]SA4503 accumulation and sigma-1 receptor expression in pons. CONCLUSIONS Cholinergic lesioning causes an increase of sigma-1 receptor expression in a small cortical area which may be neuroprotective. Sleep deprivation decreases receptor expression in midbrain and pons.
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