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).q RSNA, 2014 Purpose:To investigate the association between left atrial (LA) function and left ventricular myocardial fibrosis using cardiac magnetic resonance (MR) imaging in a multi-ethnic population. Materials and Methods:For this HIPAA-compliant study, the institutional review board at each participating center approved the study protocol, and all participants provided informed consent. Of 2839 participants who had undergone cardiac MR in 2010-2012, 143 participants with myocardial scar determined with late gadolinium enhancement and 286 age-, sex-, and ethnicity-matched control participants were identified. LA volume, strain, and strain rate were analyzed by using multimodality tissue tracking from cine MR imaging. T1 mapping was applied to assess diffuse myocardial fibrosis. The association between LA parameters and myocardial fibrosis was evaluated with the Student t test and multivariable regression analysis. Results:The scar group had significantly higher minimum LA volume than the control group (mean, 22.0 6 10.5 [standard deviation] vs 19.0 6 7.8, P = .002) and lower LA ejection fraction (45.9 6 10.7 vs 51.3 6 8.7, P , .001), maximal LA strain (S max ) (25.4 6 10.7 vs 30.6 6 10.6, P , .001) and maximum LA strain rate (SR max ) (1.08 6 0.45 vs 1.29 6 0.51, P , .001), and lower absolute LA strain rate at early diastolic peak (SR E ) (20.77 6 0.42 vs 21.01 6 0.48, P , .001) and LA strain rate at atrial contraction peak (SR A ) (21.50 6 0.62 vs 21.78 6 0.69, P , .001) than the control group. T1 time 12 minutes after contrast material injection was significantly associated with S max (b coefficient = 0.043, P = .013), SR max (b coefficient = 0.0025, P = .001), SR E (b coefficient = 20.0016, P = .027), and SR A (b coefficient 20.0028, P = .01) in the regression model. T1 time 25 minutes after contrast material injection was significantly associated with SR max (b coefficient = 0.0019, P = .016) and SR A (b coefficient = 20.0022, P = .034). Conclusion:Reduced LA regional and global function are related to both replacement and diffuse myocardial fibrosis processes.Clinical trial registration no. NCT00005487q RSNA, 2014

C-preladenant is a selective antagonist for mapping of cerebral adenosine A receptors (ARs) by PET. This is a first-in-human study to examine the safety, radiation dosimetry, and brain imaging of C-preladenant in healthy human subjects. Dynamic C-preladenant PET scans (90 min) were obtained in 5 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. For anatomic coregistration, T1-weighted MRI was performed. The total distribution volume () was estimated using 1- and 2-tissue-compartment models (1T and 2T, respectively). The distribution volume ratio (DVR) was calculated from of target and reference region and obtained with a noninvasive Logan graphical reference tissue method (* = 30 min). The applicability of a shortened protocol as an alternative to the 90-min PET scan was investigated. Tracer biodistribution and dosimetry were determined in 3 healthy male subjects, using serial whole-body PET scans acquired over 2 h after C-preladenant injection. There were no serious adverse events in any of the subjects throughout the study period. C-preladenat readily entered the brain, with a peak uptake in the putamen and head of the caudate nucleus 30-40 min after tracer injection. Other brain regions showed rapid clearance of radioactivity. The regional distribution ofC-preladenant was consistent with known AR densities in the brain. At pseudoequilibrium (reached at 40 min after injection), stable target-to-cerebellar cortex ratios of around 3.8-10.0 were obtained. The 2T fit better than the 1T in the low-density AR regions. In contrast, there were no significant differences between 1T and 2T in the high-AR-density regions. DVRs in the putamen and head of the caudate nucleus were around 3.8-10.3 when estimated using a Logan graphical reference tissue method with cerebellum as the reference region. PET scanning at 50 or 70 min can provide the stable DVR estimates within 10% or 5% differences at most, respectively. The radioactivity was mainly excreted through the hepatobiliary system after C-preladenant injection. As a result, the absorbed dose (μGy/MBq) was highest in the gallbladder wall (mean ± SD, 17.0 ± 2.5) and liver (11.7 ± 2.1). The estimated effective dose forC-preladenant was 3.7 ± 0.4 μSv/MBq. This initial evaluation indicated thatC-preladenat is suitable for imaging of ARs in the brain.

The title compound N,N'-bistosyl-1H,4H-quinoxaline-2,3-dione (TsQD) provides peroxyoxalate chemiluminescence (PO-CL) when reacted with hydrogen peroxide in the presence of fluorophores. The chemiluminescence (CL) efficiency of TsQD was superior to that of other related compounds such as bis(2,4,6-trichlorophenyl) oxalate (TCPO), a typical oxalate for the peroxyoxalate PO-CL, under an aqueous condition. Factors affecting the PO-CL efficiency are discussed from the viewpoint of the structures of the substrates and the electronic nature of the fluorophores. A linear correlation of the logarithmic values evaluated from the CL quantum yields with the oxidation potentials of the aromatic fluorophores supports the involvement of the chemically initiated electron exchange luminescence (CIEEL) mechanism in both TsQD- and TCPO-CL systems. Also, an excellent Hammett relationship was derived from the correlation between the sigma(+) values and the relative singlet excitation yields in TsQD-CL enhanced by a series of fluorescent para,para'-disubstituted distyrylbenzenes.

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Mast cells (MC) play an important role in allergic and non-allergic immune responses. Activation of human MC is modulated by several cell surface inhibitory receptors, including recently identified Allergin-1 expressed on both human and mouse MC. Although Allergin-1 suppresses IgE-mediated, mast cell–dependent anaphylaxis in mice, the expression profile and function of Allergin-1 on human primary MC remains undetermined. Here, we established a seven-color flow cytometry method for assessing expression and function of a very small number of human primary MC. We show that Allergin-1S1, a splicing isoform of Allergin-1, is predominantly expressed on human primary MC in both bronchoalveolar lavage (BAL) fluid and nasal scratching specimens. Moreover, Allergin-1S1 inhibits IgE-mediated activation from human primary MC in BAL fluid. These results indicate that Allergin-1 on human primary MC exhibits similar characteristics as mouse Allergin-1 in the expression profile and function.

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