Estimation of the deformations induced by articulated bodies: Registration of the spinal column

We present a new non-rigid registration algorithm estimating the displacement field generated by articulated bodies. Indeed the bony structures between different patient images may rigidly move while other tissues may deform in a more complex way. Our algorithm tracks the displacement induced in the column by a movement of the patient between two acquisitions. The volumetric deformation field in the whole body is then inferred from those displacements using a linear elastic biomechanical finite element model. We demonstrate in this paper that this method provides accurate results on 3D sets of computed tomography (CT), MR and positron emission tomography (PET) images and that the results of the registration algorithm show significant decreases in the mean, min and max errors.     

Effects of dietary soybean lecithin on plasma lipid transport and hepatic cholesterol metabolism in rats

Dietary lecithin can stimulate bile formation and biliary lipid secretion, particularly cholesterol output in bile. Studies also suggested that the lecithin-rich diet might modify hepatic cholesterol homeostasis and lipoprotein metabolism. Therefore, we examined hepatic activities of 3-hydroxy-3 methylglutaryl coenzyme A reductase "HMG -CoA reductase", cholesterol 7 alpha-hydroxylase and acyl-CoA: cholesterol acyltransferase "ACAT" as well as plasma lipids and lipoprotein composition in rats fed diets enriched with 20% of soybean lecithin during 14 days. We also evaluated the content of hepatic canalicular membrane proteins involved in lipid transport to the bile (all P-glycoproteins as detected by the C 219 antibody and the sister of P-glycoprotein "spgp" or bile acid export pump) by Western blotting. As predicted, lecithin diet modified hepatic cholesterol homeostasis. The activity of hepatic HMG-CoA reductase and cholesterol 7 alpha-hydroxylase was enhanced by 30 and 12% respectively, while microsomal ACAT activity showed a dramatic decrease of 75%. As previously reported from ACAT inhibition, the plasma level and size of very low-density lipoprotein (VLDL) were significantly decreased and bile acid pool size and biliary lipid output were significantly increased. The canalicular membrane content of lipid transporters was not significantly affected by dietary lecithin. The current data on inhibition of ACAT activity and related metabolic effects by lecithin mimic the previously reported effects following drug-induced inhibition of ACAT activity, suggesting potential beneficial effects of dietary lecithin supplementation in vascular disease.     

Assessing the role of the T cell receptor beta gene enhancer in regulating coding joint formation during V(D)J recombination

To assess the role of the T cell receptor (TCR) beta gene enhancer (Ebeta) in regulating the processing of VDJ recombinase-generated coding ends, we assayed TCRbeta rearrangement of Ebeta-deleted (DeltaEbeta) thymocytes in which cell death is inhibited via expression of a Bcl-2 transgene. Compared with DeltaEbeta, DeltaEbeta Bcl-2 thymocytes show a small accumulation of TCRbeta standard recombination products, including coding ends, that involves the proximal Dbeta-Jbeta and Vbeta14 loci but not the distal 5' Vbeta genes. These effects are detectable in double negative pro-T cells, predominate in double positive pre-T cells, and correlate with regional changes in chromosomal structure during double negative-to-double positive differentiation. We propose that Ebeta, by driving long range nucleoprotein interactions and the control of locus expression and chromatin structure, indirectly contributes to the stabilization of coding ends within the recombination processing complexes. The results also illustrate Ebeta-dependent and -independent changes in chromosomal structure, suggesting distinct modes of regulation of TCRbeta allelic exclusion depending on the position within the locus.     

A comprehensive radiation hybrid map of bovine Chromosome 26 (BTA26): comparative chromosomal organization between HSA10q and BTA26 and BTA28

In this study, we present a comprehensive 3000-rad radiation hybrid (RH) map of bovine Chromosome (Chr) 26 (BTA26) with 80 markers including 50 genes or ESTs: 44 have an ortholog mapping to human Chr 10 (HSA10) and 29 to mouse Chr (MMU) 7, 10, and 19. Moreover, 12 other HSA10 genes were integrated in a newly developed RH map of BTA28 (seven represent new assignments). The available draft of the mouse genome allowed us to present a detailed picture of the distribution of conserved synteny segments among the three species (human, cattle, and mouse) and to propose a simple model of the comparative chromosomal organization between the long arm of HSA10 and BTA26 and 28. Finally, the INRA bovine BAC library was screened for most of the BTA26 markers considered in this study to provide anchors for the bovine physical map.