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Claude Férec

Publications and source records attributed to Claude Férec.

44 records · Page 3Linked to original sources
PubMed2002

Spatial and temporal distribution of cystic fibrosis and of its mutations in Brittany, France: a retrospective study from 1960.

Cystic fibrosis (CF) is the most common severe inherited disorder that affects children in Caucasian populations. The aim of this study was to define the spatial and temporal distribution of CF and its mutations in Brittany (western France) where the frequency of the disease is high. We retrospectively registered all CF patients born in Brittany since 1960 by cross-checking various data sources (e.g. medical care centres, genetics laboratories, hospital archives). Councils were contacted so that the place of residence of patients at birth could be determined. Moreover, the spectrum of CF transmembrane conductance regulator (CFTR) mutations and their spatial distribution across Brittany were determined. A total of 520 patients was registered in this study. The incidence of CF was assessed according to administrative (department, district) and diocesan divisions of Brittany and its evolution analysed over four decades. The incidence of CF was 1/2630, with a west/east gradient that was confirmed over time (Finistère: 1/2071 vs Ille-et-Vilaine: 1/3286). At present, the incidence of CF is decreasing, mainly as a result of prenatal diagnosis. An excellent mutation detection rate of 99.7% was obtained. Western Brittany presented a specific spectrum of mutations: 1078delT (9.4% of mutated alleles in the diocese of Cornouaille), G551D (7.7% in the diocese of Léon), 4005+1G-->A (2.9% in Cornouaille) and W846X (1.5% in western Brittany). On the other hand, the eastern region showed a spectrum more similar to the overall picture in France as a whole. This study enabled a precise measurement of the incidence of CF in Brittany to be obtained. The high frequency of the CFTR mutated alleles may result from founder effects and genetic drifts. Moreover, the study brings together the regional specificities of the CFTR gene and highlights disparities that exist in this part of France, both in incidence and in mutation distribution. These are attributable to different degrees of isolation and of population movements between the eastern and western parts of the region. Given that this is the first time that such a detailed study of the CFTR gene has been performed on a large population, this heightened knowledge of the epidemiology of CF in Brittany should provide a basis for the improvement of diagnostic strategies and refinement of genetic counselling.

Alleles↗
PubMed2002

Proteolipidic vectors for gene transfer to the lung.

In order to develop improved synthetic gene transfer vectors, we have synthesized bifunctional peptides composed of a DNA binding peptide (P2) and ligand peptides selected by the phage display technique on tracheal epithelial cells. We have evaluated the capacity of these peptides to enhance the gene transfer efficiency of the cationic lipid DOTAP to the mouse lung. To optimize the in vivo transfection efficiency, we first compared the efficiency of DOTAP to transfect the lung by either intravenous injection or aerosolization. We then tested DNA/Peptide/DOTAP complexes formed at different Peptide/DNA and DOTAP/DNA charge ratios. Under optimal conditions, precompaction of DNA by peptide P2 gave a higher expression in the mouse lung using the luciferase reporter gene than DOTAP/DNA complexes. A further increase of transfection efficiency was obtained with the bifunctional peptide P2-9. Experiments performed with the GFP reporter gene showed expression in the alveolar parenchyme.

Administration, Inhalation↗
PubMed2002

Determination of the relative contribution of three genes-the cystic fibrosis transmembrane conductance regulator gene, the cationic trypsinogen gene, and the pancreatic secretory trypsin inhibitor gene-to the etiology of idiopathic chronic pancreatitis.

In the last 5 years, mutations in three genes, the cystic fibrosis transmembrane conductance regulator (CFTR) gene, the cationic trypsinogen (PRSS1) gene, and the pancreatic secretory trypsin inhibitor (PSTI) gene, have been found to be associated with chronic pancreatitis (CP). In this study, using established mutation screening methods, we systematically analysed the entire coding sequences and all exon/intron junctions of the three genes in 39 patients with idiopathic CP (ICP), with a view to evaluating the relative contribution of each gene to the aetiology of the disease. Our results demonstrate that, firstly, 'gain-of-function' mutations in the PRSS1 gene may occasionally be found in an obvious ICP subject. Secondly, presumably 'loss-of-function' mutations in the PSTI gene appear to be frequent, with a detection rate of at least 10% in ICP and, finally, abnormal CFTR alleles are common: at least 20% of patients carried one of the most common CFTR mutations, and about 10% of patients were compound heterozygotes, having at least one 'mild' allele. Thus, in total, about 30% of ICP patients carried at least one abnormal allele in one of the three genes, and this is the most conservative estimate. Moreover, a trans-heterozygous state with sequence variations in the PSTI/CFTR genes was found in three patients. However, an association between the 5T allele in intron 8 of the CFTR gene and ICP remains unproven.

Chronic Disease↗
PubMed2002

Association between genetically determined pancreatic status and lung disease in adult cystic fibrosis patients.

STUDY OBJECTIVES: The association between genotype and phenotype in cystic fibrosis (CF) has been clearly established for pancreatic status, but not for lung disease. DESIGN: Retrospective study. SETTING: A respiratory unit of a teaching hospital. PATIENTS: We studied 51 adult CF patients for whom current data and genotype were available. Thirty-seven patients carried two severe mutations associated with pancreatic insufficiency phenotype (group S). Fourteen patients carried at least one mild (and dominant) mutation associated with pancreatic sufficiency phenotype (group M). MEASUREMENTS: We compared the course of the disease between the two groups, looking for a genotype/phenotype association for lung disease. RESULTS: The mean age of the population was 30 years. Patients with two severe mutations presented more severe disease with earlier onset (1.7 years vs 7.9 years, p = 0.0001). They presented with a more severe respiratory impairment, with a lower mean FEV(1) (29% of predictive value vs 58% of predictive value, p < 0.001); a higher Pseudomonas colonization rate (97% vs 57%, p < 0.01); a more frequent end-stage respiratory insufficiency, defined by a FEV(1) < 30% (73% vs 29%, p < 0.05); and a more marked yearly decline of FEV(1) (3% vs 1.4%, p < 0.001). By multivariate logistic regression analysis, carrying two severe mutations was the only independent predictor of a terminal respiratory insufficiency (relative risk, 6.75; 95% confidence interval, 1.79 to 26.50; p = 0.003). CONCLUSION: This study suggests that pulmonary disease appears to be associated with the severity of CF transmembrane regulator mutations.

Adolescent↗
PubMedDate not supplied

Efficient gene transfer into human epithelial cell lines using glycosylated cationic carriers and neutral glycosylated co-lipids.

To date, no clear and constant relationship has been established between the chemical structure and the efficiency of non-viral transfection reagents. Despite the improvement of synthetic transfection systems, the capacity to transfect a target cell in a specific way is still a major challenge that gene therapy needs to overcome to be successful. Consequently, we developed a strategy aimed specifically at improving transfection of targeted human epithelial cells and to examine the possible effects of electrostatic interactions. Our attention therefore focused on the development of novel glycosylated formulations, based upon the introduction of one or two different carbohydrate ligands into (i) cationic lipid structures and (ii) synthetic neutral lipids incorporated into DNA and lipoplexes. Then, these formulations were tested in vitro on two human cell lines [HeLa and 16HBE14o(-)]. We report here that one of those formulations (CG 1/DOPE) is more efficient than DOTAP/DOPE. We determined that this non-viral transfection process is partially due to an endocytotic phenomenon mediated by targeting specific receptors directed toward specific carbohydrate elements. This was shown on 16HBE14o(-) cells where we observed a 43% and a 69% decrease in transfection when we blocked these receptors by the addition of free lactose and mannose, respectively. These results highlight the large adaptability of such monocationic glycolipids in the context of targeting and gene delivery.

Binding, Competitive↗
PubMedDate not supplied

The use of in situ hybridization to study the transgene pathway following cellular transfection with cationic phosphonolipids.

Gene therapy is a promising field of research and biotechnological development. Considering their safety and non-immunogenicity, cationic lipids are widely used for gene transfer in vitro and show promise for in vivo gene transfer applications. However, a better understanding of the mechanisms by which transfection occurs and the limiting steps in cellular transfer of foreign DNA are critical for significant improvements of gene transfer. In this work, we have traced the plasmid DNA into human hematopoietic cell line (K562) using the in situ hybridization method in order to define the main difficulties in transfection and to design new agents better adapted to cellular constraints. In this hematopoietic cell line, after showing the efficiency of our synthetic vectors and optimizing their formulation, we observed that only 5 h after transfection the nucleus to cytoplasm signal ratio was three to one, whereas at 24 h it was one to one. In parallel, the level of the reporter protein strongly increased between these times. Those results emphasize the rapidity of transfection and lead one to imagine chemical modifications adjusted to the environment.

Biotinylation↗
PubMedDate not supplied

Phenotypic expression of the C282Y/Q283P compound heterozygosity in HFE and molecular modeling of the Q283P mutation effect.

In Caucasians, from 4 to 35% of hereditary hemochromatosis (HH) patients carry a least one chromosome without a common assigned HFE mutation (i.e., C282Y, H63D, and S65C). We have undertaken a D-HPLC scanning of the HFE coding region in such patients in order to identify uncommon mutations liable to explain their high transferrin saturation level. Twenty HH patients from Brittany carrying at least one chromosome without an assigned mutation were selected on the basis of a transferrin saturation level with the following threshold: > or = 60% in men and > or = 50% in women, in the absence of other known causes of iron disorders. This strategy allowed us to detect a heterozygous sequence variant in exon 4 of the HFE gene from one individual who was also heterozygous for C282Y. Subsequent DNA sequencing analysis identified an adenine to cytosine transversion at position 848 which changes amino acid 283 from glutamine to proline (Q283P). Family study revealed a clear association between the C282Y/Q283P compound heterozygote genotype and the development of HH. Molecular modeling studies are in favor of a destabilizing effect of the Q283P mutation on the tertiary structure of the HFE protein. This is the first report of a natural protein variant describing the introduction of a proline in a central beta-strand position. Our approach may have practical implications in screening strategies for hereditary hemochromatosis, molecular diagnosis, and HFE structure-function relationships.

DNA Mutational Analysis↗