Odd-skipped genes specify the signaling center that triggers retinogenesis in Drosophila

5 páginas, 4 figuras.Although many of the factors responsible for conferring identity to the eye field in Drosophila have been identified, much less is known about how the expression of the retinal `trigger', the signaling molecule Hedgehog, is controlled. Here, we show that the co-expression of the conserved odd-skipped family genes at the posterior margin of the eye field is required to activate hedgehog expression and thereby the onset of retinogenesis. The fly Wnt1 homologue wingless represses the odd-skipped genes drm and odd along the anterior margin and, in this manner, spatially restricts the extent of retinal differentiation within the eye field.This work has been funded through grants BMC2003-06248 (Ministerio de Educación y Ciencia, Spain) and POCTI/BIA-BCM/56043/2004 [Fundação para a Ciência e a Tecnologia (FCT), Portugal], which are co-funded by FEDER, to F.C. C.B-P. and J.B. are funded by FCT.Peer reviewe

Ultrasound for Distal Forearm Fracture:A Systematic Review and Diagnostic Meta-Analysis

STUDY OBJECTIVE:To determine the diagnostic accuracy of ultrasound for detecting distal forearm fractures. METHODS:A systematic review and diagnostic meta-analysis was performed according to the PRISMA statement. We searched MEDLINE, Web of Science and the Cochrane Library from inception to September 2015. All prospective studies of the diagnostic accuracy of ultrasound versus radiography as the reference standard were included. We excluded studies with a retrospective design and those with evidence of verification bias. We assessed the methodological quality of the included studies with the QUADAS-2 tool. We performed a meta-analysis of studies evaluating ultrasound to calculate the pooled sensitivity and specificity with 95% confidence intervals (CI95%) using a bivariate model with random effects. Subgroup and sensitivity analysis were used to examine the effect of methodological differences and other study characteristics. RESULTS:Out of 867 publications we included 16 studies with 1,204 patients and 641 fractures. The pooled test characteristics for ultrasound were: sensitivity 97% (CI95% 93-99%), specificity 95% (CI95% 89-98%), positive likelihood ratio (LR) 20.0 (8.5-47.2) and negative LR 0.03 (0.01-0.08). The corresponding pooled diagnostic odds ratio (DOR) was 667 (142-3,133). Apparent differences were shown for method of viewing, with the 6-view method showing higher specificity, positive LR, and DOR, compared to the 4-view method. CONCLUSION:The present meta-analysis showed that ultrasound has a high accuracy for the diagnosis of distal forearm fractures in children when used by proper viewing method. Based on this, ultrasound should be considered a reliable alternative, which has the advantages of being radiation free

The SpoMBe pathway drives membrane bending necessary for cytokinesis and spore formation in yeast meiosis

Precise control over organelle shapes is essential for cellular organization and morphogenesis. During yeast meiosis, prospore membranes (PSMs) constitute bell-shaped organelles that enwrap the postmeiotic nuclei leading to the cellularization of the mother cell's cytoplasm and to spore formation. Here, we analysed how the PSMs acquire their curved bell-shaped structure. We discovered that two antagonizing forces ensure PSM shaping and proper closure during cytokinesis. The Ssp1p-containing coat at the leading edge of the PSM generates a pushing force, which is counteracted by a novel pathway, the spore membrane-bending pathway (SpoMBe). Using genetics, we found that Sma2p and Spo1p, a phospholipase, as well as several GPI-anchored proteins belong to the SpoMBe pathway. They exert a force all along the membrane, responsible for membrane bending during PSM biogenesis and for PSM closure during cytokinesis. We showed that the SpoMBe pathway involves asymmetric distribution of Sma2p and does not involve a GPI-protein-containing matrix. Rather, repulsive forces generated by asymmetrically distributed and dynamically moving GPI-proteins are suggested as the membrane-bending principle