PubMed Health⌕ Search

Biomedical subjects

C Marsac

Publications and source records attributed to C Marsac.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Mitochondrial function and mitochondrial DNA in a series of 64 patients suspected of having mitochondrial myopathy].

Biochemical results concerning 64 patients suspected of mitochondrial myopathies are presented. Four clinical groups were studied including 21 encephalomyopathies, 42 ocular myopathies, 8 isolated myopathies and 3 cardiomyopathies. In 26 cases, the coexistence of a normal mitochondrial DNA and a mutated mitochondrial DNA (heteroplasmy) was found (19 simple deletions, 4 multiple deletions and 3 punctual mutations) and all cases presented with ocular disorders (excepted 2 cases with MERRF). Furthermore, 1 complex I deficiency (1 ocular myopathy), 1 complex IV deficiency (1 adult encephalomyopathy type Leigh), 3 complexes I + IV deficiencies (2 cases with a cardiomyopathy and 1 familial MELAS) and 2 pyruvate (1 adult from of Leigh's encephalomyopathy) dehydrogenase deficiencies (clinically and genetically different) did not show evidence of mitochondrial DNA mutation.

Blotting, Western↗
PubMed1990

Identification of point mutations by mispairing PCR as exemplified in MERRF disease.

The point mutation in the tRNA(Lys) gene of mitochondrial DNA (mtDNA) from patients with myoclonic epilepsy and ragged red fibers (MERRF) was quantitatively analyzed after digestion with the restriction endonuclease Nae I of the PCR amplified DNA. Since the point mutation is not part of a restriction site for a commonly available restriction endonuclease, the Nae I restriction site was introduced by PCR using a mispairing primer. The percentage of mutated mtDNA was determined in a few hairs of five members of an affected family by counting the radioactivity of the fragments after PCR amplification with labelled dATP.

Adolescent↗
PubMed1990

Immunohistochemical demonstration of fibre type-specific isozymes of cytochrome c oxidase in human skeletal muscle.

The immunohistochemical reaction of monoclonal as well as polyclonal antibodies against cytochrome c oxidase (COX) subunits with serial sections of normal human skeletal muscle was investigated. The stronger reactivity of polyclonal antibodies to COX subunits II-III and VIIbc with type I as compared to type II fibres, correlated well with the higher histochemical reactivity of NADH dehydrogenase, succinate dehydrogenase and cytochrome c oxidase in type I fibres. In contrast an almost exclusive reaction of a monoclonal antibody against subunit IV with type I fibre and a preponderant reaction of a polyclonal antibody against subunits Vab with type II fibres was obtained. Antibodies against subunits I, Vb and VIc did not reveal a fibre-type-specific reactivity. The data indicate in human muscle the occurrence of fibre type-specific isozymes of cytochrome c oxidase differing in subunits IV and Va or Vb.

Antibodies, Monoclonal↗
PubMed1990

Evidence of mitochondrial impairment during cardiac allograft rejection.

NADH laser fluorimetry and mitochondrial oxigraphy were used to study myocardial oxidative energy metabolism during cardiac allograft rejection. Heterotopic cardiac transplantation was performed on Lewis rats; allografts (with Fischer rat donors) were compared with isografts (with Lewis rat donors). In vivo and in vitro assays were performed six days after transplantation. Myocardial NADH fluorescence was recorded in vivo from grafted hearts, at baseline; during brief, complete ischemia; and during reperfusion. Oxygen consumption of mitochondria isolated from both native and grafted hearts was determined. Neither baseline levels nor maximum ischemic levels of NADH fluorescence (F0 = k[NADH]) were found to be significantly different between allografts (0.45 +/- 0.05 to 0.87 +/- 0.10) and isografts (0.45 +/- 0.04 to 1.11 +/- 0.05). During recovery, the rate of fluorescence decrease was significantly lower in allografts than in isografts (0.024 +/- 0.001 vs. 0.038 +/- 0.002 delta F0.s-1, P less than 10(-3], indicating a lower rate of NADH reoxidation. In the presence of malate and glutamate substrates, mitochondrial O2 consumption was significantly lower in allografts than in isografts (30 +/- 9 vs. 100 +/- 15 nanoatoms O2. min-1.mg prot-1, P less than 10(-2]. These results indicate that mitochondrial oxidative metabolism was impaired during the rejection process. Such energy production disturbances may contribute to the dysfunction of rejecting hearts.

Animals↗
PubMed1989

Mapping of heteroplasmic mitochondrial DNA deletions in Kearns-Sayre syndrome.

Kearns-Sayre syndrome (KSS) is a progressive neuromuscular disease characterised by ophtalmoplegia, cardiac bloc branch, pigmentary retinopathy associated with abnormal mitochondrial function. We have studied the mitochondrial DNA organization of patients presenting KSS and have found large deletions ranging from 3 to 8.5 kilobase pairs. DNA molecules containing deletion are accompanied by the presence of the normal sized mtDNA molecule forming heteroplasmic genomes. The deletions always map in the region which is potentially single stranded during mitochondrial DNA replication. The deletions differ in length and position between individuals but are similar within the different tissues of an individual suggesting that they arise during or before embryogenesis.

Biopsy↗
PubMed1989

Immunocytological and histochemical correlation in Kearns-Sayre syndrome with mtDNA deletion and partial cytochrome c oxidase deficiency in skeletal muscle.

We report histochemical, immunocytochemical, biochemical and molecular studies of skeletal muscle from a 23-year-old man with Kearns-Sayre syndrome. Southern blot analysis revealed a 4.7 kb heteroplasmic deletion of the mitochondrial DNA mapping within genes coding for subunits of complexes I, IV and V of the respiratory chain and for tRNA. Cytochrome c oxidase activity was decreased by 30% in isolated muscle mitochondria, without alteration of the Km. Histochemical and immunocytochemical correlation studies for cytochrome c oxidase revealed a lack of activity in 34% of individual muscle fibers including all the typical ragged-red fibers and a low percentage of immunodeficient fibers.

Adult↗
PubMed1987

Phosphorus NMR spectroscopy study of muscular enzyme deficiencies involving glycogenolysis and glycolysis.

We used phosphorus NMR spectroscopy to study 16 patients with muscular enzyme deficiencies affecting glycogenolysis and glycolysis. Study of phosphomonoester (Pm) kinetics and intracellular pH during exercise and recovery provided criteria for the distinction of these metabolic myopathies by NMR spectroscopy. The Pm peak was undetectable in patients lacking debrancher enzyme or phosphorylase. By contrast, in phosphofructokinase (PFK) or phosphoglycerate kinase (PGK) deficiency, the Pm peak was larger than that of inorganic phosphate in exercise, whereas it was always smaller in normal subjects. During recovery, the disappearance of Pm was slower in PGK than in PFK deficiency.

Adolescent↗
PubMed1987

The French and North American phenotypes of pyruvate carboxylase deficiency, correlation with biotin containing protein by 3H-biotin incorporation, 35S-streptavidin labeling, and Northern blotting with a cloned cDNA probe.

Cultured skin fibroblasts from 16 patients with either French or American pyruvate carboxylase (PC) deficiency were examined for their ability to incorporate 3H-biotin into proteins. Cell extracts were also examined for the presence of biotin-containing proteins with 35S-streptavidin, immunoreactive protein with anti-PC antibody, and PC mRNA by Northern blotting with a PC cDNA probe. All the North American presentation patients showed a 3H-biotin protein, a streptavidin protein, and an anti-PC precipitable protein at 125 kilodaltons on sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cellular proteins. They also showed a detectable mRNA species for PC on Northern blotting. Of the French presentation patients, five showed very low or absent 3H-biotin protein, streptavidin protein, and anti-PC precipitable protein at 125 kilodaltons. Three French presentation patients showed PC protein to be present on the basis of these techniques. Similarly, five showed either very low or absent mRNA for PC on Northern blotting whereas three gave evidence of the presence of PC-specific mRNA. Thus, whereas the North American presentation of PC deficiency is associated with the presence of a mature biotin containing protein of the correct molecular weight, the French presentation may, in some (but not in all) cases, have both absent PC protein and absent PC mRNA.

Bacterial Proteins↗
PubMed1986

Disorders of the pyruvate dehydrogenase complex.

Pyruvate dehydrogenase deficiency may be a non-specific consequence of many different neurological degenerative disorders. There are also serious methodological problems in estimating the activity of this enzyme complex.

Acetyl Coenzyme A↗
PubMed1985

Pyruvate carboxylase deficiencies: complementation studies between "French" and "American" phenotypes in cultured fibroblasts.

Pyruvate carboxylase (PC) deficiencies (McKusick 26615) are heterogeneous clinically and biochemically. We performed a complementation study with fibroblast strains from seven patients, (four patients with "French" phenotype, two patients with "American" phenotype, one patient with biotin responsive multiple carboxylase deficiency, MCD). The six isolated pyruvate carboxylase mutants (two cross-reacting material CRM -ve and four CRM +ve) failed to complement each other, but did complement a form of biotin responsive MCD.

Amino Acid Metabolism, Inborn Errors↗
PubMed1983

Biotin dependent carboxylase activities in normal human and multicarboxylase deficient patient fibroblasts: relationship to the biotin content of the culture medium.

Three mitochondrial carboxylase activities can be depleted in skin fibroblasts from patients with the neonatal form of multiple carboxylase deficiency when the biotin content of the culture medium is lowered to 25 nmol/l. On the other hand this depletion can be achieved in control fibroblasts or in fibroblasts from patients with the late onset form of the deficiency when avidin (50 U/l) is added to the culture medium. The kinetics of the carboxylase activity decrease are nevertheless identical for control and for both types of fibroblasts. After depletion, control and late onset form fibroblasts recover their carboxylase activities at the same rate, whereas fibroblasts with the neonatal form of deficiency need longer times or higher concentrations of biotin to restore their carboxylase activities. These results are consistent with previous hypotheses concerning the origin of both forms of the deficiency. In addition, this technique provides a convenient access to human apocarboxylases, i.e. substrates for in vitro holocarboxylase synthetase investigation.

Biotin↗
PubMed1982

Congenital lactic acidosis, alpha-ketoglutaric aciduria and variant form of maple syrup urine disease due to a single enzyme defect: dihydrolipoyl dehydrogenase deficiency.

A 6-month-old girl with vomiting, hypotonia and motor retardation was found to have elevated blood lactate, pyruvate, and branched chain amino acids associated with ketoglutaric aciduria. The combination of a congenital lactic acidosis with a variant form of maple syrup urine disease and ketoglutaric aciduria suggested a defect of a single component, common to pyruvate dehydrogenase, to branched chain ketoacid dehydrogenase, and to alpha-ketoglutarate dehydrogenase. Dihydrolipoyl dehydrogenase is the common component (E3). The three enzyme activities and the E3 component activity were found to be reduced in liver and cultured fibroblasts, thus confirming that a single defect of this component can result in a multiple deficiency involving several oxidative decarboxylation reactions.

Acidosis↗
PubMed1981

Biotin dependent multiple carboxylase deficiency presenting as a congenital lactic acidosis.

Two patients presented in early childhood with (i) alopecia, skin rashs, and dermatitis, (ii) severe hypotonia, ataxia and motor retardation, (iii) frequent episodes of ketoacidosis with hyperlactacidemia. Propionic and methylcrotonic aciduria only appeared on high protein diet. Mitochondrial biotin-dependent carboxylase activities were decreased in the liver and leukocytes, but were similar to control values in fibroblasts cultured in a biotin-free medium. In addition, the plasma biotin was found to be significantly lower than in control subjects. These disorders responded to biotin administration, pointing to biotin-dependent multiple carboxylase deficiencies (MCD). Our report stresses the polymorphism of MCD and suggests that MCD could be of two types: impaired vitamin metabolism (absorption, plasma transport), might result in low plasma biotin with generalized MCD involving acetyl CoA carboxylase. Defective mitochondrial holocarboxylase synthetase might lead to a pure mitochondrial MCD, with fibroblastic deficiency and presumably normal biotin metabolism.

Acidosis↗