We report on a study of the narrow Fe K\(\alpha\) line and reflection spectrum in the well-known Seyfert-2 AGN, NGC 4388. X-ray spectra summed from two extensive NICER monitoring campaigns, separated ...by years, show strong evidence of variation in the direct continuum and reflected emission, but only small variations in the obscuring gas. Fits to the spectra from individual NICER observations find a strong, positive correlation between the power-law photon index, \(\Gamma\), and direct flux that is commonly observed in unobscured AGN. A search for a reverberation lag between the direct and reflected spectra -- dominated by the narrow Fe K\(\alpha\) emission line -- measures a time scale of \(t = 16.37^{+0.46}_{-0.38}\) days, or a characteristic radius of \(r=1.374_{-0.032}^{+0.039}\times10^{-2}\) pc \(=3.4_{-0.1}^{+0.1}\times10^4\;GM/c^2\). Only one cycle of this tentative lag is observed, but it is driven by a particularly sharp drop in the direct continuum that leads to the subsequent disappearance of the otherwise prominent Fe K\(\alpha\) line. Physically motivated fits to high-resolution Chandra spectra of NGC 4388 measure a line production radius of \(r =2.9^{+1.2}_{-0.7}~\times 10^{4}~GM/c^{2}\), formally consistent with the tentative lag. The line profile also prefers a Compton-thick reflector, indicating an origin in the disk and/or thick clumps within a wind. We discuss the strengths and weaknesses of our analysis and methods for testing our results in future observations, and we note the potential for X-ray reverberation lags to constrain black hole masses in obscured Seyferts wherein the optical broad line region is not visible.
The mechanisms responsible for inhomogeneous myocardial blood flow after oral administration of a large dose (300 mg) of dipyridamole were assessed in 27 patients with serial thallium-201 ...single-photon emission computed tomography (SPECT) and simultaneous 2-dimensional echocardiograms. Myocardial tomographic images were obtained 50 minutes and 3 to 4 hours after administration of dipyridamole. Two-dimensional echocardiograms were recorded at baseline and then every 15 minutes for 60 minutes. Dipyridamole caused only a mild reduction in blood pressure (from 129 +/- 18 to 126 +/- 16 mm Hg) and a mild increase in heart rate (from 69 +/- 15 to 73 +/- 4 beats/min). Sixteen patients had perfusion defects after dipyridamole by SPECT, which underwent partial or total filling-in. Fourteen of these patients (87.5%) had either a new abnormality or further deterioration of a preexisting wall motion abnormality by 2-dimensional echocardiography, and thus were considered to have developed transient ischemia during dipyridamole administration. Ten of 11 patients (91%) with normal perfusion or fixed defects by SPECT had no further deterioration in wall motion after oral dipyridamole, and were thus considered to have no evidence of myocardial ischemia. In conclusion, most patients with transient thallium-201 defects after dipyridamole develop transient worsening of resting wall motion by 2-dimensional echocardiography, suggestive of true myocardial ischemia. Because myocardial oxygen demand, as indicated by the heart rate-blood pressure product, did not change significantly, the mechanism of myocardial ischemia in these patients is likely to be diminished regional blood flow related to a "subendocardial steal" induced by dipyridamole.
Reply Arbustini, Eloisa; Narula, Navneet; Dec, G William ...
Journal of the American College of Cardiology,
06/2014, Volume:
63, Issue:
23
Journal Article
Peer reviewed
...the biventricular and predominantly left ventricular variants (5) as well as the less specific genetic basis of the ARVC/D cannot be ignored. ...ARVC/D-related desmosome gene defects are also ...known to be associated with dilated cardiomyopathy (6) and dilated cardiomyopathy-related genes such as LMNA may also result in ARVC/D (7). Because MOGE(S) descriptors are flexible, it is rather simple to provide comprehensive information such as MA(m4x3)+D(AVB) OHGADEG-LMNAp. Lys117Arg+DSC2p.Ala596Val SA-I, where both LMNA and PKP2 variants could contribute to the phenotype, one to the dilated cardiomyopathy with atro-ventricular block LMNA p.(Lys117Arg) and one of still unknown pathogenicity (DSC2 p.Ala596Val, http://www.arvcdatabase.info/) to the ARVC/D traits.
Reply Arbustini, Eloisa; Narula, Navneet; Dec, G. William ...
Journal of the American College of Cardiology,
06/2014, Volume:
63, Issue:
23
Journal Article
État de mal épileptique et gatifloxacine Koussa, S.; Hage Chahine, S.; Zoghbi, A. ...
Revue neurologique,
2007, 2007-1-00, Volume:
163, Issue:
1
Journal Article
Peer reviewed
Le potentiel épileptogène des quinolones diffère d’un agent à l’autre. Les rares crises d’épilepsie imputées à la gatifloxacine ont été observées avec la voie intraveineuse.
Deux patientes âgées ...présentèrent un état de mal épileptique généralisé après la prise orale du produit aux doses usuelles. Une histoire de crises d’épilepsie était le seul facteur retrouvé. L’IRM cérébrale était sans particularité. Chez une patiente, l’EEG montrait des paroxysmes bilatéraux continus, à prédominance frontale. Les suites étaient favorables.
L’utilisation des quinolones incite à la prudence chez les sujets âgés, notamment épileptiques.
The epileptogenic potential of quinolones differs from one product to the other. The rare epileptic seizures induced by gatifloxacin were seen with the intravenous route.
We report two old ladies presenting with generalized status epilepticus after being treated orally with normal doses of gatifloxacin, with a good recovery. Past medical history of convulsion was the only factor found. Brain MR imaging was unremarkable. In one patient, EEG showed continuous bilateral paroxysmal discharges, predominantly frontal.
Caution is warranted when using quinolones in elderly patients, especially those suffering from epilepsy.
This study was designed to test the accuracy of echocardiographic radial shortening measurements during variable degrees of regional dysfunction produced by 14 transient (≤10 min) coronary occlusions ...(8 left anterior descending coronary artery, 6 left circumflex coronary artery) Followed by up to 24 h of reperfusion in chronically instrumented conscious dogs. Independent measurement of regional myocardial thickening was obtained using epicardial pulsed Doppler probes and served as a standard for comparison. Radial shortening fraction was derived from two-dimensional short-axis views along 12 equidistant radii. Six reference systems from the epicardial and endocardial centers of geometry (centroids) in a fixed or a floating position were explored.
In the ischemic zone, percent thickening fraction averaged 22 ± 5% at baseline, decreased to −4 ± 4% during occlusion and gradually returned to baseline values after reperfusion. Percent change in radial shortening correlated significant by with percent change in thickening fraction in the ischemic zone. The worst correlation was seen with the Heating endocardial centroid (τ = 0.68), and the best was observed with the epicardial Heating reference (r = 0.91). Moreover, the epicardial floating reference provided narrower 95% confidence limits of radial shortening and less heterogeneity among radii than did fixed reference systems.
Thus, compared with an independent standard, echocardiographic measurement of radial shortening from the short axis provided recognition of discrete grades of regional dysfunction induced by transient reversible ischemia. This technique may be amenable for serial assessment of regional function after interventions on the ischemic myocardium.
Myocardial contrast echocardiography (MCE) is a recently developed technique to assess myocardial perfusion. Previous studies have shown that MCE frequently underestimates coronary reserve as ...compared with other methods. Previous reports have suggested that some of the limitations of MCE are due to the nonlinear processing algorithms of the ultrasound systems. Therefore we designed an in vitro model to study the effects of various processing algorithms and levels of acoustic power (AP) on the relation between concentration of echocontrast and mean pixel intensities. A beaker containing a commercially produced, diluted solution of sonicated albumin microspheres was imaged with a commercial Hewlett Packard ultrasound system, and mean pixel intensities were determined with an off‐line computer system. The solution was imaged at a wide range of APs (40–10 dB) and time gain compensation (40–60 dB). Concentration versus intensity curves were generated using all possible combinations of compression and processing algorithms available on the ultrasound system used. Contrast effect diminished rapidly when exposed to high AP. Lower powers had less effect on contrast intensity duration, with no effect seen below 20 dB. Changes in time gain compensation did not affect contrast intensities. Regardless of the processing algorithm examined, the relation between concentration of echocontrast and mean pixel intensities was near linear in the first two to three concentrations; thereafter, the curves flattened during increasing concentrations of contrast. At higher concentrations, acoustic shadowing produced a decrease in pixel intensities. Thus, in this in vitro model, measurements of pixel intensities offer the opportunity of quantitating sonicated albumin microsphere concentration, but only at the lower range (6.25 × 10−5/ml sonicated albumin microspheres/ml of solution) of the contrast concentration. These results could have important clinical implications.
PDF
