Assisted quantification of abdominal adipose tissue based on magnetic resonance images

An assisted method to segment Visceral Adipose Tissue (VAT) and Subcutaneous Adipose Tissue (SAT) from Magnetic Resonance Imaging (MRI) slices is presented. The segmentation process, called shape-based segmentation, consists in three main steps: 1) to draw a series of closed curves at different slices that separates the abdominal structures of interest, 2) to generate a 3D model from the closed curves for each abdominal structure by using shape-based interpolation and 3) to apply a segmentation algorithm to define the adipose tissue. The 3D models considerably simplify the problem since the abdominal structures are separated, and in turn, this reduces the possibility of large segmentation errors. In addition, a fully automatic segmentation procedure was also implemented. Twenty slices of MRI at the abdominal region for each of twelve subjects were analysed. The results of the shape-based and automatic segmentation were compared with the expert segmentation carried out in the slice located at the umbilicus level. Correlation Coefficient (CC) and volume error (VE) were used as performance measures. The comparison between the expert and shape-based segmentation for SAT yielded results of CC= 0.974 and VE=-0.01 ± 5.8 cm3, while for VAT the performance indexes were CC= 0.993 and VE= 0.9 ± 1.8 cm3. The results suggest that the shape-based segmentation provides an accurate and simple assessment of the abdominal adiposity with minimal human intervention and it could be used as a simple tool in clinics

Insertionslinien als Werkzeuge für funktionelle Genomforschung

Huep G, Kleinbölting N, Appelhagen I, Viehöver P, Weisshaar B. Insertionslinien als Werkzeuge für funktionelle Genomforschung. BIOspektrum. 2013;19(6):639-641

Plant gene expression response to Agrobacterium tumefaciens

To elucidate the nature of plant response to infection and transformation by Agrobacterium tumefaciens, we compared the cDNA-amplified fragment length polymorphism (AFLP) pattern of Agrobacterium- and mock-inoculated Ageratum conyzoides plant cell cultures. From 16,000 cDNA fragments analyzed, 251 (1.6%) were differentially regulated (0.5% down-regulated) 48 h after cocultivation with Agrobacterium. From 75 strongly regulated fragments, 56 were already regulated 24 h after cocultivation. Sequence similarities were obtained for 20 of these fragments, and reverse transcription–PCR analysis was carried out with seven to confirm their cDNA-AFLP differential pattern. Their sequence similarities suggest a role for these genes in signal perception, transduction, and plant defense. Reverse transcription–PCR analysis indicated that four genes involved in defense response are regulated in a similar manner by nonpathogenic bacteria, whereas one gene putatively involved in signal transduction appeared to respond more strongly to Agrobacterium. A nodulin-like gene was regulated only by Agrobacterium. These results demonstrate a rapid plant cell response to Agrobacterium infection, which overlaps a general response to bacteria but also has Agrobacterium-specific features