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M Rousseau

Publications and source records attributed to M Rousseau.

At least 19 recordsLinked to original sources
PubMed2006

Identification of calconectin, a calcium-binding protein specifically expressed by the mantle of Pinctada margaritifera.

Nacre or mother-of-pearl in the shell of Pinctada margaritifera is composed of 95-99% calcium carbonate and 1-5% organic matrix. In this study, we developed an original technique to characterize the genes differentially expressed in nacre-forming cells (NFC) by combining suppression subtractive hybridization (SSH), to establish a cDNA subtractive library, with rapid amplification of cDNA ends (RACE)-PCR. Seventy-two specific cDNA sequences have been obtained so far. These include a protein containing two EF-hand Ca2+-binding domains which was completely sequenced after amplification by RACE-PCR. Its specific expression as well as the specificity of the SSH method was confirmed by semi-quantitative RT-PCR on NFC and mantle cells.

Amino Acid Sequence↗
PubMed2006

An enhanced microsatellite map of diploid Fragaria.

A total of 45 microsatellites (SSRs) were developed for mapping in Fragaria. They included 31 newly isolated codominant genomic SSRs from F. nubicola and a further 14 SSRs, derived from an expressed sequence tagged library (EST-SSRs) of the cultivated strawberry, F. x ananassa. These, and an additional 64 previously characterised but unmapped SSRs and EST-SSRs, were scored in the diploid Fragaria interspecific F2 mapping population (FVxFN) derived from a cross between F. vesca 815 and F. nubicola 601. The cosegregation data of these 109 SSRs, and of 73 previously mapped molecular markers, were used to elaborate an enhanced linkage map. The map is composed of 182 molecular markers (175 microsatellites, six gene specific markers and one sequence-characterised amplified region) and spans 424 cM over seven linkage groups. The average marker spacing is 2.3 cM/marker and the map now contains just eight gaps longer than 10 cM. The transferability of the new SSR markers to the cultivated strawberry was demonstrated using eight cultivars. Because of the transferable nature of these markers, the map produced will provide a useful reference framework for the development of linkage maps of the cultivated strawberry and for the development of other key resources for Fragaria such as a physical map. In addition, the map now provides a framework upon which to place transferable markers, such as genes of known function, for comparative mapping purposes within Rosaceae.

Chromosome Mapping↗
PubMed2005

Thirteen years of culture-positive M. bovis-BCG infection in an IL-12Rbeta1 deficient patient: treatment and outcome.

Patients with mutations in the IFNgamma/IL-12 pathway show an exquisite susceptibility to mycobacterial diseases. An IL-12Rbeta1 deficient patient with impaired intestinal absorption suffered from a 13 year culture-positive Mycobacterium bovis-BCG infection with acquired multidrug resistance. A combined parenteral and enteral anti-mycobacterial treatment, including recombinant IFNgamma, helped to clear his infection.

Adolescent↗
PubMed2003

Biomineralisation markers during a phase of active growth in Pinctada margaritifera.

To search for the biochemical parameters involved in calcium and carbonate transport during crystal formation and biomineralisation in nacreous molluscs, the carbonic anhydrase activity, the levels of calciotropic hormones in hemolymph and in tissues and the circulating concentration of calcium were measured in pearl oysters (Pinctada margaritifera) during a phase of active growth. Activity of carbonic anhydrase in gill tissue increased linearly with age of the animals, while no age variation in activity was noted for the mantle. The circulating level of total calcium increased during the growth of the animals. Calciotropic hormones were radioimmunoassayed in gill, mantle and hemolymph. Only a calcitonin-gene related peptide (CGRP) could be detected and its concentration decreased as a function of growth, both in hemolymph and mantle. No variation in CGRP concentration with age was observed in gill tissue. Our data demonstrate that carbonic anhydrase and a molecule biologically and immunologically related to CGRP are involved during growth of the animals. In addition, this study shows the presence of three main calcium compartments, gill, hemolymph and mantle, involved in the biomineralisation process.

Animals↗
PubMed2003

Predictors of psychological distress in family caregivers of persons with psychiatric disabilities.

The purpose of the study was to determine the relationships of primary and secondary stressors, and informal and formal supports, to psychological distress in 154 family caregivers of persons with psychiatric disabilities. All caregivers were members of self-help groups located in the Province of Quebec in Canada. Psychological distress was significantly lower among older caregivers, those working full time, and those experiencing lower objective and subjective burdens. Contrary to the hypotheses, caregivers who perceived more support from friends and had more contacts with their relatives' primary mental health providers experienced a higher level of psychological distress.

Caregivers↗
PubMed2001

Improvement in the molecular diagnosis of Machado-Joseph disease.

BACKGROUND: Direct detection of the gene mutation allows for the confirmation of the clinical diagnosis of Machado-Joseph disease (MJD), the most frequent cause of autosomal dominant spinocerebellar ataxia worldwide. OBJECTIVE: To address the main difficulties in our national MJD predictive testing program. The first was the emergence of intermediate alleles, for which it is not yet possible to determine whether they will cause disease. The second was the issue of homoallelism, ie, homozygosity for 2 normal alleles with exactly the same (CAG)(n) length, which occurs in about 10% of all test results. METHODS: A large pedigree with 1 affected patient carrying a 71 and a 51 CAG repeat and 2 asymptomatic relatives carrying the 51 CAG repeat and normal-size alleles underwent clinical and molecular studies. Intragenic haplotypes for these alleles were determined. A representative sample of the healthy population in the region was obtained to assess the distribution of the normal (CAG)(n) length. We established the genotype for 4 intragenic polymorphisms in the gene for MJD (MJD1) in 21 homoallelic individuals, to distinguish their 2 normal chromosomes. In addition, we developed a new Southern blot method to completely exclude cases of nonamplification of expanded alleles in the homoallelic individuals. RESULTS: The study of the family in which the 51 CAG repeat was found suggests that the allele is apparently not associated with disease. These intermediate alleles were not present in a large sample of the healthy population from the same region. Intragenic polymorphisms allowed distinction of the 2 different normal alleles in all cases of homoallelism. The absence of an expanded allele was also confirmed by Southern blot. CONCLUSIONS: We propose an improved protocol for molecular testing for MJD. These strategies, developed to overcome the practical difficulties mostly in the presymptomatic and prenatal diagnosis of MJD, should prove useful for other polyglutamine-related disorders.

Adult↗
PubMed2001

Class III alleles of the variable number of tandem repeat insulin polymorphism associated with silencing of thymic insulin predispose to type 1 diabetes.

Type 1 diabetes results from autoimmune destruction of the insulin-producing pancreatic beta cells. The insulin gene (INS) is also expressed in human thymus, an ectopic expression site likely involved in immune tolerance. The IDDM2 diabetes susceptibility locus maps to a minisatellite composed of a variable number of tandem repeats situated 0.5 kb upstream of INS. Chromosomes carrying the protective long INS variable number of tandem repeats alleles (class III) produce higher levels of thymic INS mRNA than those with the predisposing, short class I alleles. However, complete silencing of thymic INS transcripts from the class III chromosome was found in a small proportion of heterozygous human thymus samples. We hypothesized that the specific class III alleles found on these chromosomes silence rather than enhance thymic insulin expression. To test the prediction that these alleles are predisposing, we developed a DNA fingerprinting method for detecting two putative "silencing" alleles found in two thymus samples (S1, S2). In a set of 287 diabetic children and their parents we found 13 alleles matching the fingerprint of the S1 or S2 alleles. Of 18 possible transmissions, 12 of the S1-S2 alleles were transmitted to the diabetic offspring, a frequency of 0.67, significantly higher than the 0.38 seen in the remaining 142 class III alleles; P = 0.025. This confirms our prediction and represents an additional level of correlation between thymic insulin and diabetes susceptibility, which supports a thymic enhancer effect of the INS variable number of tandem repeats as the mechanism of IDDM2 and refines the contribution of IDDM2 genotyping to diabetes risk assessment.

Adolescent↗
PubMed2000

A new locus for generalized epilepsy with febrile seizures plus maps to chromosome 2.

Generalized epilepsy with febrile seizures plus (GEFS+) is a recently recognized but relatively common form of inherited childhood-onset epilepsy with heterogeneous epilepsy phenotypes. We genotyped 41 family members, including 21 affected individuals, to localize the gene causing epilepsy in a large family segregating an autosomal dominant form of GEFS+. A genomewide search examining 197 markers identified linkage of GEFS+ to chromosome 2, on the basis of an initial positive LOD score for marker D2S294 (Z=4.4, recombination fraction [straight theta] = 0). A total of 24 markers were tested on chromosome 2q, to define the smallest candidate region for GEFS+. The highest two-point LOD score (Zmax=5.29; straight theta=0) was obtained with marker D2S324. Critical recombination events mapped the GEFS+ gene to a 29-cM region flanked by markers D2S156 and D2S311, with the idiopathic generalized epilepsy locus thereby assigned to chromosome 2q23-q31. The existence of the heterogeneous epilepsy phenotypes in this kindred suggests that seizure predisposition determined by the GEFS+ gene on chromosome 2q could be modified by other genes and/or by environmental factors, to produce the different seizure types observed.

Age of Onset↗
PubMed1999

[13C]-Galactose breath test: correlation with liver fibrosis in chronic hepatitis C.

BACKGROUND: The galactose elimination capacity test is a quantitative liver function test that has been shown to be a potential surrogate marker for death in advanced chronic liver diseases. However, this test lacks sensitivity in early liver disease. The goal of this study was to evaluate a [13C]-galactose breath test (GBT) in a population of patients with chronic hepatitis C. DESIGN: The GBT was performed in 10 control subjects and 50 patients with chronic hepatitis C; the results were compared with the METAVIR pathological scoring of liver biopsy specimens and with standard biochemical liver function tests. RESULTS: In 10 patients, oral vs. intravenous administration of galactose yielded similar results for the GBT (3.01% +/- 0.12% dose h-1 for oral galactose vs. 2.98 +/- 0.21 for intravenous). The GBT was then performed orally in the remaining 40 patients and 10 control subjects. A significant difference was observed between control subjects and patients (4.51% +/- 0.18% vs. 2.97% +/- 0.14% dose h-1, P < 0.0001). A significant difference for GBT results was observed between each fibrosis stage, but not with regard to the activity score. CONCLUSIONS: The GBT results are dependent on the severity of liver fibrosis in chronic hepatitis C. Further studies are needed to evaluate the usefulness of the GBT for the follow-up of chronic hepatitis C.

Administration, Oral↗
PubMed1998

Prenatal diagnosis of Machado-Joseph disease by direct mutation analysis.

MJD is the most frequent dominant ataxia and an incapacitating disorder. Onset is most frequently during the reproductive years, and genetic counseling is its only means of prevention. The causative mutation--an expansion of a (CAG)n on chromosome 14q32.1--can now be directly detected. We now report the first two cases of prenatal diagnosis (PND). The first presented as a simultaneous request for predictive testing and PND at 14 weeks of pregnancy. Owing to time constraints, we performed a full protocol of counseling with shorter inter between sessions, while psycho-social evaluation of the other parent obstetric consults were also begun. We ensured that the couple wished termination if the fetus was a carrier, to avoid a presymptomatic test for the unborn child. We were thus able to deliver test results two weeks before PND. As the fetus carried an expanded allele (77 CAGs) inherited from his father, termination was performed and the couple received counselling, psychological and social support. The second case was the fetus of a carrier-mother that was diagnosed as non-carrier, also after amniocentesis.

Adult↗
PubMed1997

Influence of stiripentol on cytochrome P450-mediated metabolic pathways in humans: in vitro and in vivo comparison and calculation of in vivo inhibition constants.

OBJECTIVE: The spectrum of cytochrome P450 inhibition of stiripentol, a new anticonvulsant, was characterized in vitro and in vivo. METHODS: Stiripentol was incubated in vitro with (R)-warfarin, coumarin, (S)-warfarin, (S)-mephenytoin, bufuralol, p-nitrophenol, and carbamazepine as probes for CYPs 1A2, 2A6, 2C9, 2C19, 2D6, 2E1, and 3A4, respectively. Caffeine demethylation and the 6 beta-hydroxycortisol/cortisol ratio were monitored in vivo before and after 14 days of treatment with stiripentol as measures of CYP1A2 and CYP3A4 activity, and dextromethorphan O- and N-demethylation were used to measure CYP2D6 and CYP3A4 activity, respectively. In vivo inhibition constants for CYP3A4 were calculated with use of data that previously documented the interaction between stripentol and carbamazepine. RESULTS: In vitro, stiripentol inhibited CYPs 1A2, 2C9, 2C19, 2D6, and 3A4, with inhibition constant values at or slightly higher than therapeutic (total) concentrations of stiripentol, but it did not inhibit CYPs 2A6 and 2E1 even at tenfold therapeutic concentrations. In vivo inhibition of caffeine demethylation and dextromethorphan N-demethylation were consistent with inhibition of CYP1A2 and CYP3A4, respectively. The 6 beta-hydroxycortisol/cortisol ratio did not provide a reliable index of CYP3A4 inhibition. Inhibition of CYP2D6-mediated O-demethylation was not observed in vivo. With use of carbamazepine, in vivo inhibition constants for CYP3A4 ranged between 12 and 35 mumol/L, whereas the corresponding in vitro value was 80 mumol/L. CONCLUSIONS: Stiripentol appears to inhibit several CYP450 enzymes in vitro and in vivo. In vivo inhibition constants show that stiripentol inhibition of CYP3A4 is linearly related to plasma concentration in patients with epilepsy.

Adult↗
PubMed1997

13C-urea breath test for Helicobacter pylori: cut-off point determination by cluster analysis.

1. This study was performed on a large set of 13C-urea breath test results to determine the optimal cut-off point of the test for the diagnosis of Helicobacter pylori (Hp) infection. 2. The following steps were applied to three sets of urea breath test results obtained in three groups of subjects (696 adults before anti-Hp treatment, 1056 adults after anti-Hp treatment and 173 children under 17 years of age): (1) demonstrate the distribution of urea breath test results as a mix of two normal populations (Hp negative and Hp positive) by logarithmic transformation of the results in each group of subjects; (2) apply statistical cluster analysis to determine the separation point between Hp-negative and -positive populations; (3) calculate the mean and SD of each population, and use these parameters in the equation of the normal distribution to establish the frequency curves of Hp-negative and -positive populations; and (4) determine the cut-off point of the urea breath test as the intersection of the two curves, and the risks of error related to it. 3. The optimal cut-off point was found at +3.00 delta/1000, with a risk of false-negative or -positive response of the urea breath test of less than 3%. From this, a cut-off point of +3.00 delta/1000 for the 13C-urea breath test is recommended, with an indetermined zone between +2.5 and +3.5 delta/1000 to account for the spontaneous variation of 13CO2 in breath and the limits of GC-isotope ratio-MS analytical precision.

Adolescent↗
PubMed1996

Continuous monitoring of 13C-aminopyrine metabolism in rats: effects of cold exposure and noradrenaline.

A system was developed to allow constant monitoring of hepatic cytochrome P450 activity in awake and unrestrained rats. A continuous 13C-aminopyrine perfusion was performed, and breath samples obtained for endogenous CO2 production and 13C measurements, to calculate 13C O2 production due to aminopyrine demthylation. Increasing doses of 13C-aminopyrine produced a hyperbolic increase of expired 13CO2, compatible with an in vivo measurement of enzymatic activity. Acute-cold exposure of the rats during 13C-aminopyrine perfusion produced a two-fold increase of endogenous CO2 production, together with a 27% increased 13C-aminopyrine metabolism (p<0.05 vs basal conditions). In contrast, noradrenaline (20 microg/kg BW/min), despite a similar effect on energy expenditure, did not significantly change 13C-aminopyrine metabolism. Acute-cold exposure is known to stimulate both adrenal catecholamine secretion and the sympathetic nervous system. The observed difference in 13C-aminopyrine demthylation during cold exposure and nonadrenaline perfusion, therefore, could be due to a more specific effect of adrenal catecholamines on liver aminopyrine metabolism. These results suggest the possibility of prolonged in vivo monitoring of liver metabolism pathways such as aminopyrine demethylation, thus allowing the study of drug acute interactions with cytochrome P450 system.

Aminopyrine↗
PubMed1996

Combined endarterectomy of the internal carotid artery and persistent hypoglossal artery: an unusual case of carotid revascularization.

Persistence of the hypoglossal artery is an unusual congenital abnormality of the carotid arterial system, and the simultaneous occurrence of atheromatous disease in the internal carotid artery and persistent hypoglossal artery is even more uncommon. Carotid surgery in this situation is challenging, and the surgeon must be aware of potential inherent pitfalls. A 74-year-old woman with asymptomatic stenosis of both internal carotid and hypoglossal arteries associated with occlusion of the contralateral internal carotid artery underwent successful revascularization. The anatomy of this unusual lesion and the surgical strategies, which included cranial nerve dissection and mandibular subluxation, are reviewed.

Aged↗