163 research outputs found

    Early detection of cerebral ischemia due to pericardium traction using cerebral oximetry in pediatric minimally invasive cardiac surgery: a case report

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    Background Minimally invasive cardiac surgery (MICS) for simple congenital heart defects has become popular, and monitoring of regional cerebral oxygen saturation (rSO2) is crucial for preventing cerebral ischemia during pediatric MICS. We describe a pediatric case with a sudden decrease in rSO2 during MICS. Case presentation An 8-month-old male underwent minimally invasive ventricular septal defect closure. He developed a sudden decrease in rSO2 and right radial artery blood pressure (RRBP) without changes in other parameters following pericardium traction. The rSO2 and RRBP immediately recovered after removal of pericardium fixation. Obstruction of the right innominate artery secondary to the pericardium traction would have been responsible for it. Conclusions Pericardium traction, one of the common procedures during MICS, triggered rSO2 depression alerting us to the risk of cerebral ischemia. We should be aware that pericardium traction during MICS can lead to cerebral ischemia, which is preventable by cautious observation of the patient

    Unusual p<i>K</i><sub>a</sub> Values Mediate the Self-Assembly of Spider Dragline Silk Proteins

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    Spider dragline silk is a remarkably tough biomaterial and composed primarily of spidroins MaSp1 and MaSp2. During fiber self-assembly, the spidroin N-terminal domains (NTDs) undergo rapid dimerization in response to a pH gradient. However, obtaining a detailed understanding of this mechanism has been hampered by a lack of direct evidence regarding the protonation states of key ionic residues. Here, we elucidated the solution structures of MaSp1 and MaSp2 NTDs from Trichonephila clavipes and determined the experimental pKa values of conserved residues involved in dimerization using NMR. Surprisingly, we found that the Asp40 located on an acidic cluster protonates at an unusually high pH (∼6.5-7.1), suggesting the first step in the pH response. Then, protonation of Glu119 and Glu79 follows, with pKas above their intrinsic values, contributing toward stable dimer formation. We propose that exploiting the atypical pKa values is a strategy to achieve tight spatiotemporal control of spider silk self-assembly

    On the evolution and environmental dependence of the star formation rate versus stellar mass relation since z ˜ 2.

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    This paper discusses the evolution of the correlation between galaxy star formation rates (SFRs) and stellar mass (M*) over the last ∼10 Gyr, particularly focusing on its environmental dependence. We first present the mid-infrared (MIR) properties of the Hα-selected galaxies in a rich cluster Cl 0939+4713 at z = 0.4. We use wide-field Spitzer/MIPS 24 μm data to show that the optically red Hα emitters, which are most prevalent in group-scale environments, tend to have higher SFRs and higher dust extinction than the majority population of blue Hα sources. With an MIR stacking analysis, we find that the median SFR of Hα emitters is higher in higher density environment at z = 0.4. We also find that star-forming galaxies in high-density environment tend to have higher specific SFR (SSFR), although the trend is much less significant compared to that of SFR. This increase of SSFR in high-density environment is not visible when we consider the SFR derived from Hα alone, suggesting that the dust attenuation in galaxies depends on environment; galaxies in high-density environment tend to be dustier (by up to ∼0.5 mag), probably reflecting a higher fraction of nucleated, dusty starbursts in higher density environments at z = 0.4. We then discuss the environmental dependence of the SFR–M* relation for star-forming galaxies since z ∼ 2, by compiling our comparable, narrow-band-selected, large Hα emitter samples in both distant cluster environments and field environments. We find that the SSFR of Hα-selected galaxies (at the fixed mass of log (M*/M⊙) = 10) rapidly evolves as (1 + z)3, but the SFR–M* relation is independent of the environment since z ∼ 2, as far as we rely on the Hα-based SFRs (with M*-dependent extinction correction). Even if we consider the possible environmental variation in the dust attenuation, we conclude that the difference in the SFR–M* relation between cluster and field star-forming galaxies is always small (≲0.2 dex level) at any time in the history of the Universe since z ∼ 2

    Prediction of carotid artery in-stentrestenosis by quantitative assessment ofvulnerable plaque using computed tomography

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    Background and purpose To assess the relationship between plaque volume evaluated by multidetector computed tomographic angiography (MDCT) and in-stent restenosis (ISR) after carotid artery stenting (CAS). Materials and methods From a retrospectively maintained database, data were collected for 52 patients with carotid artery stenosis treated with CAS between 2007 and 2012. We defined ISR of ≥ 50% as a peak systolic velocity ≥ 200 cm/s on echo-duplex scan. Carotid plaques were subdivided into four components according to radiodensity in Hounsfield units (HU) as follows: 600 HU. Risk factors that influenced ISR were compared using univariate and multivariate Cox regression analyses. Results During a median follow-up period of 36 months, ISR of ≥ 50% was detected in five patients (9.6%). In the univariate Cox proportional hazard regression analysis, renal insufficiency, coronary artery disease, total plaque volume, and plaque volumes with radiodensities < 0 and ≥ 600 HU increased the risk for ISR (P < 0.10). When the significant risk factors determined from the univariate analysis were subjected to a multivariate analysis, only the volumes of the plaque components with radiodensities < 0 HU independently predicted the development of ISR (hazard ratio: 1.041; 95% confidence interval: 1.006–1.078; P = 0.021). Conclusion Our data suggest that the high volume of the plaque components with radiodensities < 0 HU was independently associated with the increased risk of ISR after CAS. Quantitative and qualitative tissue characterizations of carotid plaques using MDCT might be a useful predictive tool of the development of ISR.Embargo Period 12 month
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