Malformation uropathies and multiple malformation syndromes

The authors, from their experience emphasize the associated malformations' frequency in major congenital urinary tract malformations (26,9%). It is essential to recognize in these multiple defects some certified syndromes - inherited or not. The most associations are still unknown, nevertheless the genetic counselling require an accurate diagnosis.     

Selective Coronary Angiography Using a Percutaneous Femoral Technique

Successful use, in 650 patients over a period of two years, of a percutaneous femoral technique of selective coronary angiography is described. This technique is carried out with the use of mouldable, manually preshaped polyethylene catheters. Preparation of the material and the different steps of the technique are discussed. Excellent flexibility and plastic memory of this catheter material allow easy, rapid and consistent percutaneous insertion and removal of catheters and intubation of the coronary arteries.     

Instability of long inverted repeats within mouse transgenes.

Various sequences in the mammalian genomes are unstable. One class of sequence arrangement is long inverted repeats, which are known to be unstable in bacteria and yeast. While in mammals some evidence suggests that short inverted repeats (<10 bp long) may show instability, nothing is known about the stability of long inverted repeats. Here we describe two unrelated multicopy transgenes in the mouse (loci 109 and OX1-5), each of which contains a long inverted repeat that shows substantial mitotic instability. This instability also occurs in the germline so that mutant transgenes appear within pedigrees at a high frequency. The mutation processes acting at these two inverted repeats are complex and can involve insertion or deletion, and can result in stabilization of the transgene. At transgene 109 mutational events range from very small rearrangements at the centre of the inverted repeat to complete transgene deletion. In addition we show that the rates of mutation at the inverted repeat of transgene OX1-5 can vary between the male and female germlines and between inbred strains of mice, suggesting the possibility of a genetic analysis to identify loci that modulate inverted repeat instability.     

Cystic fibrosis in the population of Reunion Island

The frequencies of the delta F 508 mutation and haplotypes linked to the cystic fibrosis (CF) gene and detected with DNA probes XV-2C and KM-19 have been studied in the population of Reunion Island, a French province located in the Indian Ocean. The deletion was present in 41.3% of CF chromosomes, whereas this proportion is about 70% in the French population. The delta F 508 mutation was associated with the haplotype B defined by the DNA markers XV-2C (allele 1) and KM-19 (allele 2) in 76.4% of CF chromosomes, while this proportion is over 90% in the French population. Founder effect, genetic drift and admixture can explain these differences.     

Topological constraints in nucleic acid hybridization kinetics

A theoretical examination of kinetic mechanisms for forming knots and links in nucleic acid structures suggests that molecules involving base pairs between loops are likely to become topologically trapped in persistent frustrated states through the mechanism of ‘helix-driven wrapping’. Augmentation of the state space to include both secondary structure and topology in describing the free energy landscape illustrates the potential for topological effects to influence the kinetics and function of nucleic acid strands. An experimental study of metastable complementary ‘kissing hairpins’ demonstrates that the topological constraint of zero linking number between the loops effectively prevents conversion to the minimum free energy helical state. Introduction of short catalyst strands that break the topological constraint causes rapid conversion to full duplex.     

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.     

Synthesis and biological activity of 4-alkoxy chalcones: potential hydrophobic modulators of P-glycoprotein-mediated multidrug resistance

A series of 4-alkoxy-2′,4′,6′-trihydroxychalcones have been synthesized and evaluated for their ability to inhibit P-glycoprotein-mediated multidrug resistance (MDR) by direct binding to a purified protein domain containing an ATP-binding site and a modulator-interacting region. The introduction of hydrophobic alkoxy goups at position 4 led to much more active compounds as compared to the parent chalcone. The binding affinity increased as a function of the chain length, up to the octyloxy derivative for which a K_D of 20 nM was obtained.