Surgical repair of severe mitral valve regurgitation complicated by incomplete cor triatriatum

AbstractA 69-year-old woman with exertional dyspnea was referred emergently to our hospital for further evaluation. Transthoracic echocardiography showed severe mitral valve regurgitation and moderate tricuspid regurgitation, which were thought to be the main cause of her heart failure. An electrocardiogram showed paroxysmal atrial fibrillation. Mitral and tricuspid repair and pulmonary vein isolation were scheduled. Intraoperative transesophageal echocardiography revealed a fibromuscular diaphragm and multiple ostia in the left atrium, strongly suggesting cor triatriatum. After left atriotomy, an incomplete transverse membrane was identified in the chamber. The membrane was resected and the mitral valve was repaired; then a tricuspid annuloplasty was performed, and the pulmonary veins were isolated bilaterally. Her postoperative course was uneventful. Cor triatriatum is a rare congenital anomaly, and in some cases is associated with mitral regurgitation. In patients with severe mitral regurgitation, we recommend preoperative transesophageal echocardiography to obtain a correct diagnosis. We should evaluate carefully moderate to severe mitral regurgitation without pulmonary hypertension or left atrial dilatation taking cor triatriatum into consideration.<Learning objective: Cor triatriatum is a rare congenital anomaly and in some cases is associated with mitral regurgitation. In patients with severe mitral regurgitation, preoperative transesophageal echocardiography is recommended to get a correct diagnosis. We should evaluate carefully moderate to severe mitral regurgitation without pulmonary hypertension or left atrial dilatation taking cor triatriatum into consideration.

Dust Coagulation Regulated by Turbulent Clustering in Protoplanetary Disks

The coagulation of dust particles is a key process in planetesimal formation. However, the radial drift and bouncing barriers are not completely resolved, especially for silicate dust. Since the collision velocities of dust particles are regulated by turbulence in a protoplanetary disk, turbulent clustering should be properly treated. To that end, direct numerical simulations (DNSs) of the Navier–Stokes equations are requisite. In a series of papers, Pan & Padoan used a DNS with Reynolds number Re ~ 1000. Here, we perform DNSs with up to Re = 16,100, which allow us to track the motion of particles with Stokes numbers of 0.01 lesssim St lesssim 0.2 in the inertial range. Through the DNSs, we confirm that the rms relative velocity of particle pairs is smaller by more than a factor of two, compared to that by Ormel & Cuzzi. The distributions of the radial relative velocities are highly non-Gaussian. The results are almost consistent with those by Pan & Padoan or Pan et al. at low Re. Also, we find that the sticking rates for equal-sized particles are much higher than those for different-sized particles. Even in the strong-turbulence case with α-viscosity of 10−2, the sticking rates are as high as gsim50% and the bouncing probabilities are as low as ~10% for equal-sized particles of St lesssim 0.01. Thus, turbulent clustering plays a significant role in the growth of centimeter-sized compact aggregates (pebbles) and also enhances the solid abundance, which may lead to the streaming instability in a disk

Cellular Polyamine Catalogues of the Five Classes of the PhylumProteobacteria: Distributions of Homospermidine within the ClassAlphaproteobacteria, Hydroxyputrescine within the ClassBetaproteobacteria, Norspermidine within the ClassGammaproteobacteria, and Spermine within the ClassesDeltaproteobacteria and Epsilonproteobacteria

Cellular polyamines extracted from reclassified or newly validated 47 alphaproteobacteria, 46 betaproteobacteria, 96 gammaproteobacteria, 12 deltaproteobacteria and 10 epsilonproteobacteria were analyzed by high-performance liquid chromatography. Homospermidine was widely distributed within the class Alphaproteobacteria, however, homospermidine-dominant type, spermidine-dominant type and homospermidine/spermidinedominant type were found and the three triamine profiles were genus-specific. The all genera belonging to the class Betaproteobacteria, ubiquitously contained putrescine and 2- hydroxyputrescine. Triamines were absent in almost betaproteobacteria. Many genera, including psychrophilic species, of the class Gammaproteobacteria, contained putrescine and spermidine as the major polyaminenes. Diaminopropane and norspermidine were selectively distributed in several genera of the class Gammaproteobacteria. Spermidine was the major polyamine in the classes Deltaproteobacteria and Epsilonproteobacteria. Spermine was found in some thermophiles within Betaproteobacteria, Deltaproteobacteria and Epsilonproteobacteria, suggesting that the occurrence of spermine correlate to their thermophily. Additional these polyamine catalogues serve for the classification of the phylum Proteobacteria, as a chemotaxonomic marker