Improvement in the quality of the cardiac vein images by optimizing the scan protocol of multidetector-row computed tomography

The present study aimed at optimizing the scan protocol for multidetector-row computed tomography (MDCT) to adequately visualize coronary veins. Circulation time (Cir.T) was defined as the time period from the injection of contrast media into the coronary artery to the pervasion of the contrast media into the coronary sinus as observed by coronary angiography. We investigated the relation between the Cir.T and echocardiographic parameters in 64 patients. The left ventricular end-diastolic diameter (LVDd) and left ventricular end-systolic diameter (LVDs) were correlated with the Cir.T (r = 0.58, P < 0.0001, and r = 0.60, P < 0.0001 respectively). In addition, the left ventricular ejection fraction (LVEF) was negatively correlated with the Cir.T (r = 0.48, P < 0.0001). The average Cir. T was longer in patients with LVEF < 35% (8.0 s vs 6.7 s; P < 0.05) or LVDd > 55 mm (7.9 s vs 6.2 s; P < 0.05) than in the other patients. The quality of the MDCT images of the coronary veins obtained at different scan timings (coronary artery phase and 10 s or 15 s after the coronary artery phase) were graded and classified into four categories (0 = worst, 3 = best) in 25 patients with LVEF < 35%. The delays of 10 and 15 s after the coronary artery phase significantly improved the mean image quality (P < 0.05). The Cir.T was prolonged in patients with low LVEF and LV dilation. An appropriate delay improved the quality of the MDCT images of the coronary veins in patients with LV dysfunction.     

Novel Carboxamide Derivative (IS-741) Attenuates Lung Injury in Rats with Cerulein-Induced Pancreatitis Complicated by Endotoxemia

The therapeutic effects of an intravenouslyinjected carboxamide derivative (IS-741) on lung injurywere studied in rats with cerulein-induced pancreatitiscomplicated by endotoxemia. Pancreatitis was induced by four intramuscular injections of cerulein(50 g/kg at 1-hr intervals). Pancreatitis rats wereinjected intraperitoneally with 10 mg/kg oflipopolysaccharide (LPS) 6 hr following the firstcerulein injection as a challenge of endotoxemia. Ratswere divided into four groups: group I, pancreatitiswith LPS; group II, pancreatitis with LPS treated witha continuous intravenous injection of IS-741 at 0.03 mg/kg/hr); group III, pancreatitis withLPS treated with a continuous intravenous injection ofIS-741 at 0.3 mg/kg/hr); and group IV, pancreatitis withLPS treated with a continuous intravenous injection of IS-741 at 3 mg/kg/hr). IS-741 wasadministered 30 min before the endotoxemia challenge.Intense mononuclear cell infiltration and lunghemorrhage occurred in untreated pancreatitis rats withLPS (group I), but hemorrhage was not seen in group IVrats receiving a continuous injection of IS-741 shortlybefore the induction of endotoxemia. The IS-741- treatedrats (groups II, III, and IV) had lower serum concentrations of cytokine-induced neutrophilchemoattractant (CINC), as well as fewer pulmonaryinfiltrates immunoreactive for CINC or Mac-1(CD11b/CD18). The number of neutrophils infiltrating thelung in groups II, III, and IV was significantlylower than that of group I. Conversely, CINC productionby bronchoalveolar macrophages in vitro were stimulatedby LPS but were reduced by the presence of IS-741. The carboxamide derivative IS-741 effectivelyprevented pancreatitisassociated lung injury followingthe challenge of endotoxemia.     

Analysis of flow characteristics in poststenotic regions of the human coronary artery during bypass graft surgery

Poststenotic blood flow velocities were evaluated in nine patients with 75% to 99% stenosis of the left anterior descending coronary artery (LAD) during coronary artery bypass graft surgery. We used the 20 MHz 80-channel pulsed Doppler velocimeter developed in our laboratory. An operator placed a specially designed probe on the native LAD with his fingers. Before induction of extracorporeal circulation, LAD blood velocities were measured at several locations distal to the stenosis. The poststenotic flow velocities were rich in systolic flow component with reduced diastolic component. The velocity configuration in the poststenotic portions was characterized by the presence of reverse flow velocities and/or irregularity of the velocity pattern near the vessel wall, indicating the existence of flow separation and recirculation in the regions. The broadening of the velocity spectrum observed at central axial regions suggested the occurrence of flow disturbances. After grafting, the velocity waveform in the LAD beyond a vein bypass graft changed to a diastolic-predominant pattern with a relatively small systolic component. A transient bypass graft occlusion caused a marked reduction in diastolic flow velocity. The systolic-to-diastolic velocity ratio increased from 0.27 +/- 0.07 to 1.50 +/- 0.50 (p less than .01) by the graft occlusion.     

Assessment of left ventricular dysfunction by thallium-201 lung uptake during exercise in coronary artery disease

To determine the clinical significance of an increased thallium-201 (Tl-201) activity in the lung and of its clearance from the lung after exercise, computer-quantitated Tl-201 lung activity was measured and compared with hemodynamic parameters at rest and during exercise in 35 patients with coronary artery disease (CAD). All patients underwent a supine bicycle ergometer exercise test and mean pulmonary artery wedge pressure (PAWP) was measured by a Swan-Ganz catheter. Coronary angiography was also performed. On computer-generated initial and 2 and a half hours delayed anterior images, regions of interest were selected over the myocardium (M) and lung (L), and the initial L/M ratio and the (initial L)/(delayed L) ratio were calculated as indices of an increased Tl-201 lung uptake and lung clearance, respectively. The initial L/M ratio and the (initial L)/(delayed L) ratio had no significant correlation with mean PAWP at rest and had a weak negative correlation with the resting ejection fraction (r = -0.57 and r = -0.58, respectively). However, both ratios showed good correlations with mean PAWP during peak exercise (r = 0.85 and r = 0.80, respectively), suggesting that they provide useful indices for assessing the severity of exercise-induced left ventricular dysfunction.     

Si nanocrystal solution with stability for one year

Colloidal silicon nanocrystals (SiNCs) are a promising material for next-generation nanostructured devices. High-stability SiNC solutions are required for practical use as well as studies on the properties of SiNC. Here, we show a solution of SiNCs that was stable for one year without aggregation. The stable solution was synthesized by a facile process, i.e., pulsed laser ablation of a Si wafer in isopropyl alcohol (IPA). The long-term stability was due to a large ζ-potential of −50 mV from a SiNC passivation layer composed of oxygen, hydrogen, and alkane groups, according to the results of eight experiments and theoretical calculations. This passivation layer also resulted in good performance as an additive for a conductive polymer film. Namely, a 5-fold enhancement in carrier density was established by the addition of SiNCs into an organic conductive polymer, poly(3-dodecylthiophene), which is useful for solar cells. Furthermore, it was found that fresh (<1 day) and aged (4 months) SiNCs give the same enhancement. The long-term stability was attributed to a great repulsive energy in IPA, whose value was quantified as a function the distance between SiNCs.

A stable nanocrystal for one year without aggregation in a liquid is synthesized by one-step, one-pot, and one-hour process.