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T Bienvenu

Publications and source records attributed to T Bienvenu.

99 records · Page 6Linked to original sources
PubMedDate not supplied

A splicing mutation in intron 16 of the cystic fibrosis transmembrane conductance regulator gene, associated with severe disease, is common on Reunion Island.

In addition to the frequent delta F508 and Y122X mutations on cystic fibrosis (CF) chromosomes of patients from Reunion Island, one splicing mutation, 3120+1G-->A is observed relatively frequently (12.5%) in this group, in comparison with the French metropolitan population (<0.001 %). This mutation, disrupting the 5' splice donor site of intron 16, can be detected easily by restriction enzyme BstNI digestion. In 2 CF patients homozygous for this mutation, the clinical pattern was severe, with both pancreatic insufficiency and respiratory symptoms.

Child↗
PubMedDate not supplied

[RNA isolation and purification methods].

Recent advances in human, bacterial and viral genome projects and the development of quantitative real-time reverse transcription-polymerase chain reaction methods offer the possibility of analysing a large number of gene transcripts. These molecular developments represent an important advancein the field of genetics, cancer, virology, bacteriology and hematology. A limiting step remains the isolation of high quality mRNA purified from biological samples. This review describes the different methods used to isolate mRNA from biological samples and to verify RNA integrity and gives precise details about RNA storage conditions.

Blotting, Northern↗
PubMedDate not supplied

Effect of growth hormone on caffeine metabolism in hypophysectomized rats.

Two groups of six male Sprague-Dawley hypophysectomized rats (operated on day 0), 8 weeks old, treated by sc tetracosactid (ACTH, 10 micrograms every 24 hr), thyroxine (5 micrograms/100 g every 24 hr) and desmopressin (240 ng/kg/24 hr continuous infusion) received SC either saline (group I) or human growth hormone (hGH, 120 micrograms/24 hr) (group II) continuous infusion. ACTH and thyroxine were administered on days 7-19 and desmopressin and hGH on days 8-19, after surgery. They received po caffeine 4 mg/kg as citrate salt on day 15. The 0-12, 12-24 and 24-48 hr urine samples were collected after caffeine administration. Caffeine and metabolites concentrations in urines were determined using HPLC. Effect on hGH on caffeine metabolism was assessed comparing group I and group II. In 0-48-hr urine, 1-methylxanthine (154 +/- 169 pmol/g) and 3-7-dimethyluric acid (5.57 +/- 19.3 pmol/g) in group II were significantly lower than in group I (391 +/- 340 pmol/g and 262 +/- 338 nmol/g, respectively) (p less than 0.05). Other metabolites (6-amino-5-(N-methyl formylamino)-1,3-dimethyluracil included) excretion was not altered. Total, N3-, N7- and N1-demethylation ratios on 0-48 hr urine were not modified by hGH treatment. However, demethylation ratios on 12-24 and 24-48 hr (N3 + N7 + N1) and on 24-48 hr urine samples (N3 and N7) were significantly reduced in group II (p less than 0.05) suggesting an increase in the rate of appearance of demethylated metabolites during hGH treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Caffeine metabolism in liver slices during postnatal development in rats.

The metabolism of caffeine was investigated in liver slices from newborn, preweanling, postweanling, and adult rats. All metabolites were identified and quantified by HPLC without using radioactive compound. Caffeine metabolism underwent dramatic changes during maturation in rats. The specific activity of the enzyme system was extremely low when liver slices from 1-day and 7-day-old rats were used. This capacity increased gradually with increasing age and reached a peak following weaning at 21 days of age. In rat liver slices, N-1 demethylation to theobromine was the main pathway of in vitro caffeine metabolism at all ages. Theobromine represented 25% of total caffeine metabolites at day 1 and about 40% at all others ages. 1,3,7-6-amino-5-(N-formylmethylamino)-1,3-dimethyluracil is a minor metabolite in newborn (1-day-old), preweanling (7-day-old), and adult rats (120-day-old), but an important metabolite in postweanling rats. Conversely, 1,3,7-trimethyluric acid is a major metabolite in newborn and adult rats and a minor one in preweanling and postweanling rats. This liver slices model could be used as a simple and versatile model to study metabolism during maturation.

Animals↗
PubMedDate not supplied

[Molecular basis of phenotype heterogeneity in cystic fibrosis].

The cystic fibrosis transmembrane conductance regulator (CFTR) gene, responsible for the cystic fibrosis phenotype, was cloned and sequenced in 1989. Since then, more than 650 mutations have been reported. The analysis of the entire coding sequence of the CFTR gene (27 exons) has been able to characterize more than 90% of the mutations in different populations. Moreover, screening of the entire coding and flanking sequences of the CFTR gene in males with congenital bilateral absence of the vas deferens revealed that 80% of these subjects are at least heterozygous for a CF mutation. These results help to improve genetic counselling and prenatal diagnosis of cystic fibrosis. Different studies examining the relation between phenotype and genotype in CF with respect to AF508 or non delta F508 mutations have demonstrated that some "severe" mutations are strongly associated with pancreatic insufficiency or complications. It has been also showed a relationship between the presumed severity of the mutations and the observed phenotype, not only for pancreatic status, but also for the severity of the respiratory involvement. However, some studies found that some individuals do not fit the outcome of their general group of genotype. These findings reinforce the conviction that other factors besides the CFTR mutation are involved in the severity and outcome of the disease.

Cystic Fibrosis↗
PubMedDate not supplied

Mapping of the X-breakpoint involved in a balanced X;12 translocation in a female with mild mental retardation.

Balanced chromosomal abnormalities such as translocations and inversions have been identified in many genetic diseases. Cloning of the breakpoints involved in these abnormalities has led to the identification of the disease-related genes. Recent reports suggest the presence of a mental retardation locus at Xq11-12. We have identified a female patient with a balanced translocation t (X;12) (q11;q15) associated with mild mental retardation. We identified a yeast artificial chromosome spanning the X-chromosome breakpoint by using fluorescent in situ hybridization techniques. A cosmid library of this YAC has been constructed and the search for candidate genes is in progress.

Child↗