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B Mercier

Publications and source records attributed to B Mercier.

At least 109 records · Page 6Linked to original sources
PubMed1993

Detection of more than 94% cystic fibrosis mutations in a sample of Belgian population and identification of four novel mutations.

We have analysed 194 Belgian CF chromosomes using a variety of techniques: delta F508 was detected by polyacrylamide gel electrophoresis; dot blotting of PCR products was used to identify the mutations G542X, 1717-1 G-->A, and N1303K; molecular defects in exons 2, 3, 4, 5, 6b, 7, 11, 12, 13, 14a, 14b, 17b, 19, 20, and 21 were screened for by DGGE. We identified 17 mutations, which accounted for 94.3% of the Belgian CF chromosomes. Four novel mutations and a novel polymorphism were characterized. The detection of such a high proportion of Belgian CF mutations is important in understanding the functional role of the molecule and in improving prenatal and genetic diagnosis of CF.

Adolescent↗
PubMed1993

Asymptomatic carrier of two CFTR mutations: consequences for prenatal diagnosis?

The cystic fibrosis (CF) gene has been observed to have the highest frequency of mutations in the Caucasian population. Prenatal diagnosis can now be performed with a high degree of accuracy since the identification of most of the gene's mutations, as well as the characterization of intragenic markers. However, the observation of a distribution of clinical phenotypes increases the need to identify a mild phenotype and avoid false-negative diagnosis. By screening most of the exons of the CFTR gene, we showed that a supposed obligate carrier of CF was in fact an asymptomatic affected woman.

Base Sequence↗
PubMed1993

Screening for cystic fibrosis in dried blood spots of newborns.

We propose a newborn cystic fibrosis (CF) screening test based on the analysis of dried blood spot DNA by a strategy involving simple or multiplex denaturing gradient gel electrophoresis (DGGE) of PCR products of CFTR gene fragments, in conjunction with the immunoreactive-trypsin (IRT) assay. From May 1988 to May 1992 we have performed a neonatal screening programme of 42,000 newborns in Brittany. We identified 450 infants with an elevated IRT level. From this cohort, to evaluate the feasibility of measuring IRT in conjunction with mutation analysis in Guthrie cards, a pilot study was initially conducted on 200 individuals with normal IRT and 150 with raised IRT levels. Furthermore, a retrospective study was performed on 189 IRT positive cards, involving mutation scanning of exons 10 and 11 of the CFTR gene, which contains a number of frequent mutations including the deletion delta F508. We show that this approach has several implications for neonatal CF screening especially in decreasing the recall rate and detecting CF carriers.

Algorithms↗
PubMed1993

A novel mutation in exon 3 of the CFTR gene.

We have screened the 27 exons of the cystic fibrosis transmembrane conductance regulator gene in 87 non-delta F508 chromosomes of Breton origin using the combined techniques of denaturing gradient gel electrophoresis and direct sequencing. By this process, we have detected a new missense mutation, G91R, which results in an arginine for glycine at codon 91. Three affected patients with a delta F508/G91R genotype are pancreatic sufficient. Such observations could facilitate a better understanding of the functional importance of different regions of the encoded product and of the pathogenesis of the disease.

Base Sequence↗
PubMed1993

Anaerobic and aerobic components during arm-crank exercise in sprint and middle-distance swimmers.

The purpose of this investigation was to compare anaerobic and aerobic components measured during arm exercise in sprint and middle-distance swimmers and to investigate whether the peak anaerobic power:peak aerobic power ratio (W(an),peak:Waer,peak) was related to specialization for the event and to performance. The W(an0,peak, force at zero velocity (F0), and velocity at zero-force (v0), Waer,peak, peak oxygen uptake (VO2peak), and ventilatory threshold (Thv) were compared during arm exercise tests in sprint (group I, n = 8) and middle-distance (group II, n = 9) competitive male swimmers. Anaerobic indices were estimated by the force-velocity test, an anaerobic test using incremental braking forces; aerobic indices were measured during an incremental aerobic exercise test (30 W.min-1). The W(an),peak and Waer,peak were greater in group I [828 (SEM 70) W; 236 (SEM 12) W] than in group II [678 (SEM 28) W; 230 (SEM 5) W], but the differences were not significant. There were also no significant differences observed between the mean values of F0, v0, VO2peak, and Thv. The W(an0,peak:Waer,peak, however, was significantly higher in sprint swimmers (t = 3.08, P < 0.01). In seven of the swimmers, who had recently performed both the 100-m and 400-m front crawl, a relationship existed between their swim time and the W(an),peak:Waer,peak (100 m: r = -0.80, P < 0.05 and 400 m: r = +0.75, P < 0.05). In conclusion, during arm-crank exercise, we did not observe significant differences in anaerobic and aerobic components between sprint and middle-distance swimmers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Identification of 12 novel mutations in the CFTR gene.

Over 200 mutations, besides the deletion delta F508, have been identified in the CFTR gene and are known to cause CF. In order to characterize the molecular defects of non delta F508 CF chromosomes of various French origin, we have combined the techniques of denaturing gradient gel electrophoresis (DGGE) and direct sequencing to screen for mutations in the whole coding sequence of the CFTR gene corresponding to the 27 exons and their exon-intron boundaries. This approach enabled us to identify 12 novel mutations which are described here. We have systematically tested a large number of other nucleotide changes distributed in the 27 exons, each of them was clearly detected. These data support the notion that the DGGE conditions we have defined for screening coding sequence of the CFTR gene allows the identification of most of, if not all, the CFTR gene mutations.

Base Sequence↗
PubMed1993

Genotype analysis of adult cystic fibrosis patients.

To assess the relationship between the genotype and phenotype of adult CF patients we have selected from a group of 512 CF patients attending centres in France, all these of greater than 35 years. We have analysed the entire coding sequence of their CFTR genes. The complete genotype was determined in 7 of the 8 patients and clinical data regarding pancreatic, respiratory and reproductive function were carefully evaluated. All these patients are compound heterozygote, seven carrying the delta F508 and one the G542X on one allele. The other allele carried is: (i) a missense mutation located in exons coding for transmembrane region in five patients [R334W (1); I336K (2); R117H (1); H1054D (1)]; (ii) a splice mutation in two patients [2789 + 5G-->A], (iii) an uncharacterised mutations in one patient. These results strongly suggest less severe CF phenotype to be associated with these mutations and strengthen the hypothesis that less severe phenotype are genetically determined.

Adult↗
PubMed1993

[Late disclosure of intra-cerebral epidermoid cyst].

Symptoms of right hemisphere dysfunction had developed over a 10-month period in a 69-year old woman. She had experienced transient episodes of facial asymmetry for 10 years. CT scan showed a hypodense hourglass tumor extending above and below the tentorium. MRI showed a low-intensity signal with T1-weighted sequences and a high-intensity signal with T2-weighted sequences. The tumour was removed. Pathological examination proved the tumor to be an epidermoid cyst. Such a tumor may have been responsible for transient deficits in the late stages of development.

Aged↗
PubMed1992

The organisation of fibres within the rat basis pedunculi.

The organisation of corticofugal fibres within the basis pedunculi of rats was studied using wheat germ agglutinin-horseradish peroxidase as an orthograde tracer. Following cortical injections, labelled fibres were distributed within the cerebral peduncle in an orderly way. Fibres which originate from cells in the frontal cortex maintain a position in the ventromedial part of the basis pedunculi. Fibres from the occipital and temporal cortex travel in the most dorsolateral part. Somatosensory fibres travel between these two. The extent of labelled fibres within the peduncles is correlated with the relative density of corticopontine cells arising from different areas of the cerebral cortex.

Animals↗
PubMed1992

Caffeine increases maximal anaerobic power and blood lactate concentration.

The aim of this study was to specify the effects of caffeine on maximal anaerobic power (Wmax). A group of 14 subjects ingested caffeine (250 mg) or placebo in random double-blind order. The Wmax was determined using a force-velocity exercise test. In addition, we measured blood lactate concentration for each load at the end of pedalling and after 5 min of recovery. We observed that caffeine increased Wmax [964 (SEM 65.77) W with caffeine vs 903.7 (SEM 52.62) W with placebo; P less than 0.02] and blood lactate concentration both at the end of pedalling [8.36 (SEM 0.95) mmol.l-1 with caffeine vs 7.17 (SEM 0.53) mmol.l-1 with placebo; P less than 0.01] and after 5 min of recovery [10.23 (SEM 0.97) mmol.l-1 with caffeine vs 8.35 (SEM 0.66) mmol.l-1 with placebo; P less than 0.04]. The quotient lactate concentration/power (mmol.l-1.W-1) also increased with caffeine at the end of pedalling [7.6.10(-3) (SEM 3.82.10(-5)) vs 6.85.10(-3) (SEM 3.01.10(-5)); P less than 0.01] and after 5 min of recovery [9.82.10(-3) (SEM 4.28.10(-5)) vs 8.84.10(-3) (SEM 3.58.10(-5)); P less than 0.02]. We concluded that caffeine increased both Wmax and blood lactate concentration.

Adult↗
PubMed1992

Lymphoma-induced polyradiculopathy in AIDS: two cases.

Progressive polyradiculopathy is a rare, well-documented complication of the acquired immunodeficiency syndrome in man. It has been commonly attributed to a cytomegalovirus (CMV) infection. We report two HIV-infected patients with clinical and electrophysiological features of a unique, subacute, progressive polyradiculopathy. Post-mortem examination in case 1 disclosed an infiltration of the leptomeninges, the lumbar spinal cord, and the anterior and posterior roots by a B-cell immunoblastic lymphoma. Immunochemistry for HIV1 and CMV was negative in the peripheral and the central nervous system. Case 2 showed bone-marrow involvement by a Burkitt type lymphoma. Specific chemotherapy was followed by both clinical improvement of the polyradiculopathy and complete remission on a second bone-marrow biopsy. These findings may indicate that a lymphoma must also be considered a possible cause of polyradiculopathy in AIDS.

Adult↗
PubMed1992

Detection of over 98% cystic fibrosis mutations in a Celtic population.

We have conducted a large systematic study of 365 cystic fibrosis (CF) chromosomes in a Celtic population from Brittany, France, in which we have been able to identify more than 98% of the cystic fibrosis gene mutations. We detected 19 different CFTR mutations located in 9 exons. Eleven of these mutations have not been described previously and nine of them are presented in this study. The denaturing gradient gel electrophoresis strategy we have used, can be applied to other populations suggesting that population screening for CF on a large scale might be possible.

Base Sequence↗
PubMed1992

Maximal anaerobic power: relationship to anthropometric characteristics during growth.

The purpose of this study was to determine the effects of age in relation to anthropometric characteristics upon maximal anaerobic power of legs in sixty-nine young boys aged 11 to 19 years. Maximal anaerobic power (Wmax) was measured by the force-velocity test. Lean body mass (LBM) was determined from all four skin-fold thickness measurements, leg volume (LV) was estimated by anthropometric method, and anthropometric measurements were used to determine total muscular mass (TMM). Wmax increased significantly (F = 44.1, p less than 0.001) between 11 and 19 years and was correlated with LV (r = 0.84) and TMM (r = 0.88). It was most highly correlated with LBM (r = 0.94), which best explained the percentage of the total variance of Wmax (88%). Normalized Wmax (Wmax/LBM) also increased significantly between 11 and 19 years (F = 21.9, p less than 0.001). In conclusion, Wmax determined by the force-velocity test was closely related to anthropometric characteristics, especially LBM, during the growth period. Furthermore, even when corrected for lean body mass, maximal anaerobic power was always found to increase. This suggests that other undetermined factors, in addition to the amount of lean tissue mass, may explain the increase of Wmax during the force-velocity test.

Adolescent↗
PubMed1992

von Willebrand disease family studies: comparison of three methods of analysis of the von Willebrand factor gene polymorphism related to a variable number tandem repeat sequence in intron 40.

A region with a variable number of tandem ATCT repeats (VNTR) has previously been localized within intron 40 of the von Willebrand factor (vWF) gene. In the present report we describe the use of this polymorphism as a genetic marker to study the inheritance pattern in five families affected with various types of von Willebrand disease (vWD): types I, IIA, IIB, IIC and the newly characterized variant with totally defective FVIII binding. Three means of investigation previously reported, all using polymerase chain reaction (PCR) amplification of this vWF gene region, were compared in terms of informativeness. The two direct single-step procedures analysing only partial sequences of the VNTR region turned out to be less informative (three studies informative out of five) than the third method characterizing the variability of the whole VNTR sequence. This latter approach, based on the analysis of the Alu I restriction pattern of the VNTR region, was informative in all the families investigated, therefore avoiding the need to combine it with other genetic marker studies for efficient gene tracking. In conclusion, this two-step (PCR and digestion) method is the most informative for the characterization of the inheritance of the different subtypes of vWD and for the prenatal diagnosis of its severe forms.

Alleles↗
PubMed1992

Improvement in HLA-DQB typing by PCR-RFLP: introduction of a constant restriction site in one of the primers for digestion control.

The PCR-RFLP method previously reported by Inoko is a powerful technique for HLA class II typing. The reliability of RFLP interpretation depends on complete digestion by restriction endonucleases using a modified primer with restriction sites as an internal digestion control. The use of restriction enzymes which recognize specific HLA DQB allelic variations makes HLA DQB genotyping possible.

Alleles↗