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AIMS: Reduction of left atrial appendage (LAA) flow velocity (FV) is a risk factor for thrombus formation and increases the risk of stroke in patients with atrial fibrillation (AF). Furthermore, LAA morphology is correlated with stroke in patients with AF. The aim of this study was to correlate LAAFV with LAA morphology in patients with AF. METHODS AND RESULTS: We studied 96 patients (age 59.0 ± 10.2 years, 75% male) referred for radiofrequency catheter ablation for paroxysmal AF. All patients underwent computed tomography (CT) and transthoracic and transoesophageal echocardiography during sinus rhythm. LAA morphology was classified as one of the four types (chicken wing, windsock, cactus, and cauliflower) on CT images. There were significant differences in LAAFV among LAA morphologies (chicken wing 73.7 ± 21.9 cm/s, windsock 61.9 ± 19.6 cm/s, cactus 55.3 ± 14.1 cm/s, cauliflower 52.7 ± 18.1 cm/s, P = 0.008). Post hoc multiple comparisons showed that LAAFV was higher in patients with chicken wing than in those with cactus (P = 0.006, vs. chicken wing) and cauliflower (P = 0.006, vs. chicken wing), but not with windsock (P = 0.102). After adjustment for clinical and LAA anatomical covariates (orifice area, volume, and trabeculation), multiple linear regression analyses revealed that LAA morphology was an independent determinant of LAAFV [chickens wing: standardized partial regression coefficients (β) = 0.317, P = 0.0014; windsock: β = 0.303, P = 0.038]. CONCLUSION: LAA morphology is a significant determinant of LAAFV, suggesting an underlying mechanism for the association between LAA morphology and embolic events. [ABSTRACT FROM AUTHOR]

Sterols have important functions in membranes and signaling. Plant sterols are synthesized via the isoprenoid pathway by cyclization of 2,3-oxidosqualene to cycloartenol. Plants also convert 2,3-oxidosqualene to other sterol-like cyclization products, including the simple triterpene β-amyrin. The function of β-amyrin per se is unknown, but this molecule can serve as an intermediate in the synthesis of more complex triterpene glycosides associated with plant defense. β-Amyrin is present at low levels in the roots of diploid oat (Avena strigosa). Oat roots also synthesize the β-amyrin–derived triterpene glycoside avenacin A-1, which provides protection against soil-borne diseases. The genes for the early steps in avenacin A-1 synthesis [saponin-deficient 1 and 2 (Sad1 and Sad2)] have been recruited from the sterol pathway by gene duplication and neofunctionalization. Here we show that Sad1 and Sad2 are regulated by an ancient root developmental process that is conserved across diverse species. Sad1 promoter activity is dependent on an L1 box motif, implicating sterol/lipid-binding class IV homeodomain leucine zipper transcription factors as potential regulators. The metabolism of β-amyrin is blocked in sad2 mutants, which therefore accumulate abnormally high levels of this triterpene. The accumulation of elevated levels of β-amyrin in these mutants triggers a “superhairy” root phenotype. Importantly, this effect is manifested very early in the establishment of the root epidermis, causing a greater proportion of epidermal cells to be specified as root hair cells rather than nonhair cells. Together these findings suggest that simple triterpenes may have widespread and as yet largely unrecognized functions in plant growth and development. [ABSTRACT FROM AUTHOR]

AIMS: To characterise the optic nerve head (ONH) configurations of superior segmental optic hypoplasia (SSOH) using a spectral-domain optical coherence tomography (SD-OCT). METHODS: Horizontal cross-sectional images of the ONH were obtained by a SD-OCT in 20 eyes of 14 patients with clinically typical SSOH and 20 age- and refraction-matched normal eyes. RESULTS: Extension of retinal pigment epithelium (RPE) over the disc margin was observed in 20 eyes (100%) with SSOH and eight (40%) control eyes (p<0.001). The maximum length of the overhanging RPE measured at the nasal disc margin was significantly longer in eyes with SSOH than in controls (295.9±112.6 vs 24.3±33.9 µm; p<0.0001). In eyes with SSOH, the retinal nerve fibre layer (RNFL) was significantly thinner in the temporal-superior to nasal sectors (p<0.01). CONCLUSIONS: The extension of RPE over the nasal disc margin was more common and longer in eyes with SSOH than in normal eyes, suggesting that the SD-OCT findings might facilitate the diagnosis of SSOH. Substantial thinning of the RNFL was present in wider areas than previously expected in SSOH. [ABSTRACT FROM AUTHOR]