Publications by authors named "Martin-Ponthieu A"

The present work presents a "from gene defect to clinics" pathogenesis study of a patient with a hitherto unreported mutation in the CPT1A gene. In early childhood, the patient developed a life-threatening episode (hypoketotic hypoglycemia, liver cytolysis, and hepatomegaly) evocative of a mitochondrial fatty acid oxidation disorder, and presented deficient fibroblast carnitine palmitoyltransferase 1 (CPT1) activity and homozygosity for the c.1783 C > T nucleotide substitution on exon 15 of CPT1A (p.

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A female patient, with normal familial history, developed at the age of 30 months an episode of diarrhoea, vomiting and lethargy which resolved spontaneously. At the age of 3 years, the patient re-iterated vomiting, was sub-febrile and hypoglycemic, fell into coma, developed seizures and sequels involving right hemi-body. Urinary excretion of hexanoylglycine and suberylglycine was low during this metabolic decompensation.

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Background: The biochemical diagnosis of mitochondrial fatty acid oxidation defects (FAOD) currently rests on enzyme assays. A dynamic ex vivo exploration consisting of incubations of whole-blood samples with stable-labeled palmitate and determining leukocyte capacities to produce deuterated acylcarnitines was developed on healthy controls (n=52) and patients with very-long- (VLCADD) (n=2), medium- (MCADD) (n=6), or short- (SCADD) (n=1) chain acyl-CoA dehydrogenase deficiencies.

Methods: Incubations were optimized with L-carnitine and [16-(2)H(3), 15-(2)H(2)]-palmitate at 37 degrees C for various time periods on MCADD and control whole-blood samples.

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Aims/hypothesis: Whether excess glucose (glucotoxicity) and excess non-esterified fatty acids (lipotoxicity) act synergistically or separately to alter beta-cell function on Type 2 diabetes remains controversial. We examined the influence of non-esterified fatty acids, with or without concomitant increased glucose concentrations, on human islet function and on the expression of genes involved in lipid metabolism.

Methods: Human islets isolated from non-diabetic and non-obese donors were cultured with 5.

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Objective: To investigate the effects of the association of inhaled nitric oxide (iNO) and oxidant drugs (acetaminophen, phytomenadione, and EMLA cream) on methemoglobinemia during the neonatal period.

Design: Prospective, randomized, experimental study.

Setting: University Experimental Pharmacology laboratory.

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The purpose of this investigation was to examine whether inhaled nitric oxide (NO) may alter oxidative stress parameters and induce lung inflammation in moderate hyaline membrane disease (HMD). Eighteen moderately premature lambs (130 days gestation, term = 147 days) were randomly assigned to treatment with 20 ppm inhaled NO (n = 8) from the onset of ventilation or used as control (n = 10). Except inhaled NO, treatments were intentionally similar to those applied in clinical situations.

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The case is reported of a 66-year-old woman who presented with endoscopic and histological features of multiple lipid deposits in the mucosa of the sigmoid colon associated with an adenoma. Associated clinical features were abdominal pain and diarrhea. Colectomy led to the complete resolution of symptoms.

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Cuttlefish spermiogenesis is characterized by a two-step nuclear protein transition: histones-->spermatid-specific protein (protein T)-->sperm protamine (protein Sp). A similar situation can be observed in another Cephalopod species, the squid Loligo pealeii. The protein T from Loligo consists of two structural variants, T1 and T2 (molecular masses: 10788 and 10791 Da respectively), phosphorylated to different degrees (2-6 phosphate groups).

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At the end of spermiogenesis, sperm chromatin stabilization is ensured by protamine dephosphorylation and, in mammals, by the formation during epididymal transit, of intra- and inter-molecular disulfide bridges between protamines. In cuttlefish, the nuclear protein transition histones-->spermatid-specific protein T-->protamine Sp is very similar to that occurring in mammals during spermiogenesis. However, in cuttlefish, the protamine Sp is devoid of cysteine residues.

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In cuttlefish, as in selachians and mammals, spermiogenesis is characterized by the double nuclear protein transition histones----intermediate protein (protein T)----protamine (protein Sp). The cuttlefish protein T, which consists of two structural variants phosphorylated at different degrees, is the first invertebrate spermatid-specific protein to be fully characterized and sequenced. The primary structures of these two variants were established from sequence analysis and mass spectrometric data of the proteins and their fragments.

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The amino acid sequences of two cuttlefish protamine variants Sp1 and Sp2 have been established from automated sequence analysis and mass spectrometry data. Sp1 (57 residues) and Sp2 (56 residues) have molecular masses of 8410 and 8253 Da, respectively. They are almost identical proteins which differ only by one residue of arginine and the position of two of the serine residues (14 and 37 in Sp1; 13 and 35 in Sp2).

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The differently acetylated subfractions of histone H4 isolated from cuttlefish testis and from calf thymus were separated by ion exchange chromatography on sulfopropyl-Sephadex, using a shallow linear gradient of guanidine hydrochloride in the presence of 6 M urea at pH 3.0. The tetra-, tri-, di-, mono-, and nonacetylated forms of cuttlefish H4 represent 2, 6.

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The study consists in adapting two methods allowing estimation of proteins in cerebrospinal fluid and urine on a centrifugal analyzer using Coomassie Blue-SDS and benzethonium chloride. Results obtained with the two reagents are compared with turbidimetric technic using trichloroacetic acid, by statistic methods.

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The amino acid sequence of cuttlefish testis histone H2A (124 residues) was established from structural data obtained by automated sequencing of large peptides generated by the cleavage of the protein with V8 staphylococcal protease or by limited chymotryptic hydrolysis. Compared to the calf thymus homologous histone, cuttlefish H2A shows 14 substitutions (most of them conservative) and 5 deletions. Extensive evolutionary changes were mainly observed in the basic amino-terminal and carboxy-terminal regions of the molecule, which are the primary DNA-binding sites.

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We describe a new specific method for measuring lecithin, sphingomyelin, and phosphatidylglycerol in amniotic fluid by thin-layer chromatography, with use of a hydrogen flame ionization detector. After extraction and acetone precipitation to isolate surface-active lecithin, the phospholipids are separated on a thin rod of refractory and chemically stable material, having an outer coating of a bonded, sintered partition medium. Two solvent systems are used to develop the chromatograms, chloroform/methanol/water to separate lecithin and sphingomyelin, tetrahydrofuran/methylal/methanol for phosphatidylglycerol.

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