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F Duclos

Publications and source records attributed to F Duclos.

At least 19 recordsLinked to original sources
PubMed2002

[Bronchial atresia. A case report].

Bronchial atresia with mucocele and focal hyperinflation of the lung is a rare anomaly. We report the observation of a 12-year-old girl which presented a right hilar opacity on chest X-ray. The thoracic computed tomography identified an atretic segmental bronchus of the middle lobe with mucocele and focal hyperinflation of the lung. Bronchial endoscopy ruled out any acquired etiology of bronchial obstruction. The definitive diagnosis was bronchial atresia with mucocele and focal hyperinflation of the lung. This uncommon malformation is usually a radiological description. Eighty-four cases were collected in the main series in 1989. Nowadays, about 12 new cases have been published.

Bronchi↗
PubMed2000

Metabolic control of contractile performance in isolated perfused rat heart. Analysis of experimental data by reaction:diffusion mathematical model.

The intracellular mechanisms of regulation of energy fluxes and respiration in contracting heart cells were studied. For this, we investigated the workload dependencies of the rate of oxygen consumption and metabolic parameters in Langendorff-perfused isolated rat hearts.(31)P NMR spectroscopy was used to study the metabolic changes during transition from perfusion with glucose to that with pyruvate with and without active creatine kinase system. The experimental results showed that transition from perfusion with glucose to that with pyruvate increased the phosphocreatine content and stability of its level at increased workloads. Inhibition of creatine kinase reaction by 15-min infusion of iodoacetamide decreased the maximal developed tension and respiration rates by a factor of two.(31)P NMR data were analyzed by a mathematical model of compartmentalized energy transfer, which is independent from the restrictions of the classical concept of creatine kinase equilibrium. The analysis of experimental data by this model shows that metabolic stability-constant levels of phosphocreatine, ATP and inorganic phosphate-at increased energy fluxes is an inherent property of the compartmentalized system. This explains the observed substrate specificity by changes in mitochondrial membrane potential. The decreased maximal respiration rate and maximal work output of the heart with inhibited creatine kinase is well explained by the rise in myoplasmic ADP concentration. This activates the adenylate kinase reaction in the myofibrillar space and in the mitochondria to fulfil the energy transfer and signal transmission functions, usually performed by creatine kinase. The activity of this system, however, is not sufficient to maintain high enough energy fluxes. Therefore, there is a kinetic explanation for the decreased maximal respiration rate of the heart with inhibited creatine kinase: i.e. a kinetically induced switch from an efficient energy transfer pathway (PCr-CK system) to a non-efficient one (myokinase pathway) within the energy transfer network of the cell under conditions of low apparent affinity of mitochondria to ADP in vivo. This may result in a significant decrease in the thermodynamic affinity of compartmentalized ATPase systems and finally in heart failure.

Animals↗
PubMed1998

Progressive muscular dystrophy in alpha-sarcoglycan-deficient mice.

Limb-girdle muscular dystrophy type 2D (LGMD 2D) is an autosomal recessive disorder caused by mutations in the alpha-sarcoglycan gene. To determine how alpha-sarcoglycan deficiency leads to muscle fiber degeneration, we generated and analyzed alpha-sarcoglycan- deficient mice. Sgca-null mice developed progressive muscular dystrophy and, in contrast to other animal models for muscular dystrophy, showed ongoing muscle necrosis with age, a hallmark of the human disease. Sgca-null mice also revealed loss of sarcolemmal integrity, elevated serum levels of muscle enzymes, increased muscle masses, and changes in the generation of absolute force. Molecular analysis of Sgca-null mice demonstrated that the absence of alpha-sarcoglycan resulted in the complete loss of the sarcoglycan complex, sarcospan, and a disruption of alpha-dystroglycan association with membranes. In contrast, no change in the expression of epsilon-sarcoglycan (alpha-sarcoglycan homologue) was observed. Recombinant alpha-sarcoglycan adenovirus injection into Sgca-deficient muscles restored the sarcoglycan complex and sarcospan to the membrane. We propose that the sarcoglycan-sarcospan complex is requisite for stable association of alpha-dystroglycan with the sarcolemma. The Sgca-deficient mice will be a valuable model for elucidating the pathogenesis of sarcoglycan deficient limb-girdle muscular dystrophies and for the development of therapeutic strategies for this disease.

Amino Acid Sequence↗
PubMed1998

Molecular pathogenesis of muscle degeneration in the delta-sarcoglycan-deficient hamster.

The BIO14.6 hamster is an extensively used animal model of autosomal recessive cardiomyopathy and muscular dystrophy. Recently, a large deletion in the 5' end of the delta-sarcoglycan gene was found to be the primary genetic defect in the hamster. In the present investigation, we studied the effects of the delta-sarcoglycan deletion on transcription, expression, and function of the dystrophin-glycoprotein complex in skeletal and cardiac muscle. We demonstrated that in striated muscle the genetic defect leads to the complete deficiency of delta-sarcoglycan and a concomitant loss of alpha-, beta-, and gamma-sarcoglycan. In addition, absence of the sarcoglycan complex reduced the expression of alpha-dystroglycan in striated muscle fibers. These findings indicated that the primary defect in the BIO14.6 hamster leads to the dissociation of the dystroglycan complex from the sarcoglycan complex and disrupted anchorage of alpha-dystroglycan to the cell surface. Using intravenous injection of Evans blue dye as an in vivo tracer assay, we demonstrated that perturbation of the dystrophin-glycoprotein complex caused extensive fiber damage in skeletal and cardiac muscle of the BIO14.6 hamster. Based on our results, we propose that loss of delta-sarcoglycan results in the impairment of sarcolemmal integrity, finally leading to muscular dystrophy and cardiomyopathy.

Animals↗
PubMed1998

Beta-sarcoglycan: genomic analysis and identification of a novel missense mutation in the LGMD2E Amish isolate.

The sarcoglycan complex is involved in the etiology of four autosomal recessive limb-girdle muscular dystrophies (LGMD2C-F). A missense mutation (T151R) in the beta-sarcoglycan gene on chromosome 4q12 has been shown to cause a mild form of LGMD2E in 11 families from a Southern Indiana Amish community sharing a common haplotype. We now report that two sibs from another Amish family with mild LGMD2E are compound heterozygotes for chromosome 4q12 markers. In order to characterize the genetic defect in this new family, we determined the genomic organization of the beta-sarcoglycan gene. A second missense mutation (R91C) has now been identified in this LGMD2E Amish family. This mutation is also present in the homozygous state in another family of probable Amish ancestry. Finally, analysis of all the components of the dystrophin-glycoprotein complex was performed for the first time on a biopsy from a patient homozygous for the beta-sarcoglycan mutation (T151R). Interestingly, in addition to the loss of the entire sarcoglycan complex, we detected a reduction of alpha-dystroglycan which suggests a role for the sarcoglycan complex in stabilizing alpha-dystroglycan at the sarcolemma.

Adolescent↗
PubMed1998

Functional rescue of the sarcoglycan complex in the BIO 14.6 hamster using delta-sarcoglycan gene transfer.

Four types of limb-girdle muscular dystrophy (LGMD) are known to be caused by mutations in distinct sarcoglycan genes. The BIO 14.6 hamster is a model for sarcoglycan-deficient LGMD with a deletion in the delta-sarcoglycan (delta-SG) gene. We investigated the function of the sarcoglycan complex and the feasibility of sarcoglycan gene transfer for LGMD using a recombinant delta-SG adenovirus in the BIO 14.6 hamster. We demonstrate extensive long-term expression of delta-sarcoglycan and rescue of the entire sarcoglycan complex, as well as restored stable association of alpha-dystroglycan with the sarcolemma. Importantly, muscle fibers expressing delta-sarcoglycan lack morphological markers of muscular dystrophy and exhibit restored plasma membrane integrity. In summary, the sarcoglycan complex is requisite for the maintenance of sarcolemmal integrity, and primary mutations in individual sarcoglycan components can be corrected in vivo.

Adenoviridae↗
PubMed1997

Impact of restenosis after optimal directional coronary atherectomy on regional left ventricular function.

To assess the effect of optimal directional coronary atherectomy (DCA) on restenosis and left ventricular (LV) function, 95 patients who underwent DCA and adjunctive balloon angioplasty for de novo lesions were prospectively followed for 6 months. Absolute and relative coronary lumen measurements were analyzed with online quantitative coronary angiography. LV volumes, ejection fraction, and segmental wall motion were measured off-line according to the radial method for LV cineangiograms acquired in a right anterior oblique projection. Target vessels were the left anterior descending artery in 63 patients and right coronary artery in 32. Mean (+/- SD) reference diameter was 3.58 +/- 0.65 mm. Mean lumen diameter improved significantly after DCA from 1.19 +/- 0.44 to 3.03 +/- 0.45 mm, yielding a 14 +/- 10% residual stenosis. Overall angiographic restenosis rate (> 50% stenosis in diameter) at control was 23%. In patients without restenosis, there were no significant changes in LV volumes or in LV pressures. In this subgroup, ejection fraction improved significantly in the left anterior descending group (mean difference 3 +/- 10%, p < 0.04). Moreover, there was an increase in fractional shortening of all anterior segments (mean difference 11 +/- 16%, p < 0.005). Improvement in fractional shortening was less marked in the right coronary artery group even without restenosis. We conclude that: (1) optimal DCA can achieve a low restenosis rate in selected large vessels, (2) long-term beneficial effects on regional LV function are possible, particularly in patients with left anterior descending disease and in the absence of coronary restenosis.

Angioplasty, Balloon, Coronary↗
PubMed1997

Determination of the position of the pelvic girdle using surface markers.

The overall movement of the trunk is made up of two components, namely the movements of the pelvic girdle and the vertebrae. In the frontal plane, the amplitude of the pelvic movements appears to be relatively limited compared to the vertebral column whereas the pelvis makes the major contribution to the total rotational movement in the axial plane.

Adult↗
PubMed1997

[Predictive factors of coronary restenosis after optimal directional atherectomy. A multivariate analysis apropos of 102 patients].

The authors studied 102 patients prospectively who were undergoing coronary atherectomy optimised by balloon dilatation in order to assess the restenosis rate at 6 months. The coronary lesions were measured in a reproducible manner by quantitative angiography. The vessels dilated were the left anterior descending in 66 patients and the right coronary artery in 36 patients. The reference diameter was on average of 3.57 +/- 0.64 mm. Atherectomy increased the minimal diameter of the lesion of 1.20 +/- 0.44 to 3.01 +/- 0.44 mm giving a residual stenosis of 15 +/- 11%. At six months, 25% of patients had developed a restenosis (> 50% stenosis) with a residual lumen of 2.15 +/- 0.77 mm. The predictive factors of restenosis were the initial absolute gain, the length of the lesion, the reference diameter of the vessel and the presence of an endoluminal thrombus. In multivariate analysis, a small initial gain (p < 0.02) and length of stenosis (p < 0.02) were independently correlated with restenosis. The authors conclude: 1) that optimal atherectomy is associated with acceptable restenosis rates in selected vessels, 2) that short stenoses of large diameter arteries may be a privileged indication of the technique if the best results are obtained.

Adult↗
PubMed1997

[Restenosis after optimal coronary atherectomy and influence on left ventricular function].

The authors prospectively assessed 95 patients undergoing optimal guided atherectomy to assess the incidence of restenosis at 6 months. The coronary lesions were measured by a system of quantitative angiography to ensure reproducibility. Ventricular volumes, ejection fraction and segmental wall motion were assessed by ventriculography performed in the right anterior oblique projection. Sixty-three patients underwent atherectomy of the left anterior descending artery and 32 patients of the right coronary artery. The reference diameter was 3.58 +/- 0.65 mm. Atherectomy increased the minimal diameter of the lesion from 1.19 +/- 0.44 to 3.03 +/- 0.45 mm, with a residual stenosis of 14 +/- 10% of the diameter. At 6 months, 23% of patients had restenosed (> 50% stenosis) with a residual lumen at 1.16 +/- 0.39 mm. In the absence of restenosis, there was no significant change in left ventricular volumes or pressures and the global ejection fraction increased by +4 +/- 9% (p < 0.01), mainly in the group undergoing left anterior descending atherectomy. Moreover, fractional shortening increased in the anterior segments (+11 +/- 18%; p < 0.001). The authors conclude that optimal atherectomy is associated with acceptable rates of restenosis and that medium-term benefits of segmental wall motion are observed in patients without angiographic restenosis, mainly in those undergoing the procedure on the left anterior descending artery.

Adult↗
PubMed1997

[Local progression of atherosclerosis after optimal directional atherectomy. Endocoronary ultrasonography of 17 patients].

In vivo endovascular ultrasonography has confirmed the extension of atheroma to angiographically normal segments. The authors set out to determine by endocoronary ultrasonography if the introduction of the atherotome changed the intimal thickness 20 mm proximal and distal to the site treated. The area circumscribed by the external elastic layer (EEL) and the surface area of the lumen was measured in 17 patients: 1) before atherectomy; 2) after atherectomy; 3) at control 6 months later. Atherectomy immediately increased the luminal area at the site dilated from 1.9 + 0.9 to 8.1 +/- 2mm (p < 0.001). At the proximal segment, the surface area of the lumen was unchanged (mean + 0.6 +/- 1.5 mm2; p = 0.13). Similarly the procedure did not change the surface circumscribed by the EEL (mean + 0.8 +/- 3.2 mm2; p = 0.32) in this zone. The same results were observed at the distal site. At 6 months, the areas under the EEL and those of the lumen were unchanged at the unoperated sites. The mean of the differences (+/- 1 SD) for the area under the EEL was respectively -0.2 +/- 1.5 mm2 proximally and +0.7 +/- 2.5 mm2 distally. The means for the luminal area were 0.2 +/- 1 mm2 proximally and -0.01 +/- 1.1 mm2; distally. At the site of atherectomy, the luminal surface increased (+2.0 +/- 2.6 mm2; p < 0.01) as did the area under the EEL (+2.0 +/- 3.5 mm2; p < 0.05). This preliminary series shows no significant progression of atherosclerosis at the sites not affected by atherectomy.

Adult↗
PubMed1996

Characterization of delta-sarcoglycan, a novel component of the oligomeric sarcoglycan complex involved in limb-girdle muscular dystrophy.

The sarcoglycan complex is known to be involved in limb-girdle muscular dystrophy (LGMD) and is composed of at least three proteins: alpha-, beta-, and gamma-sarcoglycan. delta-Sarcoglycan has now been identified as a second 35-kDa sarcolemmal transmembrane glycoprotein that shares high homology with gamma-sarcoglycan and is expressed mainly in skeletal and cardiac muscle. Biochemical analysis has demonstrated that gamma- and delta-sarcoglycan are separate entities within the sarcoglycan complex and that all four sarcoglycans exist in the complex on a stoichiometrically equal basis. Immunohistochemical analysis of skeletal muscle biopsies from patients with LGMD2C, LGMD2D, and LGMD2E demonstrated a reduction of the entire sarcoglycan complex in these muscular dystrophies. Furthermore, we have mapped the human delta-sarcoglycan gene to chromosome 5q33-q34 in a region overlapping the recently linked autosomal recessive LGMD2F locus.

Amino Acid Sequence↗
PubMed1996

Friedreich's ataxia: autosomal recessive disease caused by an intronic GAA triplet repeat expansion.

Friedreich's ataxia (FRDA) is an autosomal recessive, degenerative disease that involves the central and peripheral nervous systems and the heart. A gene, X25, was identified in the critical region for the FRDA locus on chromosome 9q13. This gene encodes a 210-amino acid protein, frataxin, that has homologs in distant species such as Caenorhabditis elegans and yeast. A few FRDA patients were found to have point mutations in X25, but the majority were homozygous for an unstable GAA trinucleotide expansion in the first X25 intron.

Alleles↗
PubMed1996

Absence of gamma-sarcoglycan (35 DAG) in autosomal recessive muscular dystrophy linked to chromosome 13q12.

We have partially sequenced rabbit skeletal muscle gamma-sarcoglycan, an integral component of the dystrophin-glycoprotein complex. Specific antibodies were produced against a gamma-sarcoglycan peptide and used to examine the expression of gamma-sarcoglycan in skeletal muscle of patients with severe childhood autosomal muscular dystrophy linked to chromosome 13q12 (SCARMD). We show by immunofluorescence and Western blotting that in skeletal muscle from these patients gamma-sarcoglycan is completely absent and alpha- and beta-sarcoglycan are greatly reduced in abundance, whereas other components of the DGC are preserved. In addition, we show that in normal muscle alpha-, beta-, and gamma-sarcoglycan constitute a tightly associated sarcolemma complex which cannot be disrupted by SDS treatment.

Animals↗
PubMed1995

Beta-sarcoglycan: characterization and role in limb-girdle muscular dystrophy linked to 4q12.

beta-Sarcoglycan, a 43 kDa dystrophin-associated glycoprotein, is an integral component of the dystrophin-glycoprotein complex. We have cloned human beta-sarcoglycan cDNA and mapped the beta-sarcoglycan gene to chromosome 4q12. Pericentromeric markers and an intragenic polymorphic CA repeat cosegregated perfectly with autosomal recessive limb-girdle muscular dystrophy in several Amish families. A Thr-to-Arg missense mutation was identified within the beta-sarcoglycan gene that leads to a dramatically reduced expression of beta-sarcoglycan in the sarcolemma and a concomitant loss of adhalin and 35 DAG, which may represent a disruption of a functional subcomplex within the dystrophin-glycoprotein complex. Thus, the beta-sarcoglycan gene is the fifth locus identified (LGMD2E) that is involved in autosomal recessive limb-girdle muscular dystrophy.

Amino Acid Sequence↗