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Biomedical subjects

J Rey

Publications and source records attributed to J Rey.

At least 109 records · Page 6Linked to original sources
PubMed1990

Recovery of [13C]-bicarbonate as respiratory 13CO2 in parenterally fed infants.

Ten infants on continuous total parenteral nutrition (TPN) were infused with NaH13CO3 for 6 h in order to assess the amount of 13C recovered as breath 13CO2. Protein intake was 2.8 +/- 0.3 g/kg/d and non-protein energy intake 107 +/- 4 kcal/kg/d (447 +/- 18 kJ/kg/d), provided either as glucose alone or as an isoenergetic glucose-lipid mixture. In the five infants receiving glucose as the sole non-protein energy source, total CO2 production (559 +/- 50 mumol/kg/min), natural 13C abundance of breath CO2 (-11.8 +/- 0.6 delta % versus PDB) and basal 13CO2 production (6.1 +/- 0.6 mumol/kg/min) were higher than in the five infants infused the glucose-lipid mixture (465 +/- 30 mumol/kg/min, P less than 0.02; -16.1 +/- 0.5 delta %, P less than 0.01 and 5.0 +/- 0.3 mumol/kg min, P less than 0.02, respectively). There was a good agreement, in the glucose-infused infants, between the net glucose oxidation rate measured by indirect calorimetry (25.6 +/- 2 g/kg/d) and the glucose oxidation rate estimated from the 13C natural abundances of breath CO2 and infused substrates (23.5 +/- 3 g/kg/d). Steady state 13C enrichment of breath CO2 was reached in all infants after 120 min infusion and ranged from 11.0 to 21.5 delta % over baseline. Steady state 13C enrichment was negatively related to total CO2 production (r = -0.72; P less than 0.02). In contrast, steady state 13CO2 production in excess of baseline was only correlated to bicarbonate infusion rate (r = 0.95; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Bicarbonates↗
PubMed1989

CpG dinucleotides are mutation hot spots in phenylketonuria.

The coding region of the phenylalanine hydroxylase (PAH) gene contains 22 CpG dinucleotides, including five doublets in the seventh exon of the gene. We hypothesized that CpG doublets could represent mutation hot spots in PAH deficiencies and we carried out the systematic sequence analysis of exon 7 in 20 unrelated PAH-deficient kindreds of Mediterranean ancestry. This procedure resulted in the detection of two novel missense mutations whose location and nature (CG to CA and CG to TG) were consistent with the accidental deamination of a 5-methylcytosine in a CpG doublet (codon 261arg----gln and codon 252arg----trp). Moreover, the codon 261 mutation was found to be associated with mutant restriction fragment length polymorphism (RFLP) haplotype 1, the most frequent mutant RFLP haplotype at the PAH locus in the studies reported thus far. However, since the mutation was detected in only 36% of haplotype 1 mutant alleles, it appears that this haplotype at the PAH locus is genotypically heterogeneous in Mediterranean countries.

Amino Acid Sequence↗
PubMed1989

Energy substrate utilization in infants receiving total parenteral nutrition with different glucose to fat ratios.

As the fate of glucose and lipids infused during total parenteral nutrition is not well known in infants, we assessed energy substrate oxidation in 36 patients (mean age: 5.8 +/- 3.6 mo) on continuous total parenteral nutrition. The infants received isocaloric feeding regimens with nonprotein energy intakes either based on glucose alone (group 1) or on glucose-lipid mixtures providing 15% (group 2), 35% (group 3), 50% (group 4), or 70% (group 5) energy as fat for at least 6 d before glucose and fat oxidation rates were measured by open-circuit indirect calorimetry. Oxidative glucose disposal reached a maximal rate of 12.6 +/- 1.2 mg/kg.min (17.9 +/- 1.7 g/kg.d) in patients with the higher glucose infusion rates. Glucose infused in excess of maximal oxidative disposal was stored, mainly as fat. The increase in glucose infusion rate was paralleled by an increase in energy expenditure amounting to 16% of the energy value of infused glucose. Net fat oxidation was only observed in group 3 (1.6 +/- 0.7 g/kg.d), 4 (3.4 +/- 0.6 g/kg.d), and 5 (3.9 +/- 0.4 g/kg.d) patients, with glucose infusion rates lower than 18.3 g/kg.d. However, there was no further increase in fat oxidation in group 5 as compared to group 4 patients, despite a further increase in fat intake, which only resulted in increasing fat deposition. Thus, fat infusion aiming at a significant contribution to coverage of energy expenditure requires that glucose oxidation be equal to or lower than maximal oxidative glucose disposal, hence that glucose infusion rates be lower than 18 g/kg.d.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary Carbohydrates↗
PubMed1989

[Iron deficiency and Pseudomonas aeruginosa colonization in cystic fibrosis].

The incidence of iron deficiency and its relationship with the concentration or iron in sputum and the number of Pseudomonas aeruginosa (PA) colonies was studied in an unselected group of 53 cystic fibrosis (CF) patients with an age range of 3 months to 21 years. Parameters used to assess the iron status included serum iron, the % saturation of transferrin (n = 53). The number of subjects with depletion of iron stores was estimated by levels of ferritin (n = 50). The concentration of iron and of PA was measured in a subgroup (n = 24) and compared to a control group (n = 8) with pulmonary infections of varying etiology. A close correlation was found between serum iron and the % saturation of transferrin (r = 0.952; p less than 0.001). Between 22.6 to 28.3% of patients were found to be iron deficient. An abnormally low ferritin (less than 12 ng/ml) was noted in 28% of cases but no correlation could be established between changes of serum iron and ferritin levels as a function of the degree of infection and/or of inflammation. In 62% of cases (n = 15) the concentration of iron in sputum was found to be within the range of control values (12-27 mumols/l). In 38% of cases (n = 9), ferritin values were above 27 mumols/l. No correlation was found between the concentration of iron and the number of PA colonies in sputum. We can therefore conclude the following: 1) iron deficiency is more common in CF than previously reported; 2) ferritin levels constitute a poor index of iron deficiency; 3) colonisation with PA is not associated with iron content of bronchial secretions.

Adolescent↗
PubMed1989

Molecular genetics of phenylketonuria in Mediterranean countries: a mutation associated with partial phenylalanine hydroxylase deficiency.

We report the characterization of a mutation in the phenylalanine hydroxylase (PAH) gene associated with partial residual activity of the enzyme. This point mutation (280glu----lys) was found by sequencing a mutant cDNA clone derived from a needle biopsy of the liver in a child with variant form of phenylketonuria. There is a strict concordance between homozygosity for the mutation and this particular phenotype. The (280glu----lys) mutation is linked to an original and rare RFLP haplotype at the PAH locus found in south Europe and North Africa. So far, this genotype-haplotype association is both inclusive and exclusive. Thirty-three PAH-deficient patients were screened for the mutation by using polymerase chain-reaction amplification of their genomic DNA extracted from Guthrie cards. Since a large number of patients can be screened for a particular mutation by using Guthrie cards, the possibility arises of using these samples collected by national newborn screening centers for prospective and retrospective detection of other mutations in the human genome.

Amino Acid Sequence↗
PubMed1989

[Severe megaloblastic anemia in 6-month-old girl breast-fed by a vegetarian mother].

The case of a young girl, born to a woman who was a vegetarian for 18 years, is presented. She had been exclusively breast-fed until the age of 6 months when a severe anemia was discovered with an extremely low hemoglobin level (1.9 g/100 ml). Her physical growth and psychomotor development had been normal until 3 months of age. Bone marrow showed megaloblastosis and the serum B12 level was low (45 ng/l). B12 levels were also decreased in both parents (110 and 105 ng/l) and in the mother's milk (12 ng/l). Treatment with parenteral B12 was successful. The importance of a careful dietetic inquiry in the case of an infant with megaloblastic anemia is stressed and likewise, as a preventive measure during all normal pregnancies.

Anemia, Macrocytic↗
PubMed1987

[Prenatal screening for phenylketonuria in 2 families by trophoblast biopsy].

Prenatal diagnosis of phenylketonuria (PKU) is now available owing to restriction fragment length polymorphism (RFLP) of the phenylalanine hydroxylase gene. Biopsies of chorionic villi were carried ou at 11 weeks gestation in 2 families who had previously a child with the classical form of PKU and who were considered informative after DNA studies. Fetal DNA was extracted and studied with restriction enzymes selected according to the study of each family. Hybridization studies suggested that one fetus was affected by the disease and that the second was normal. Termination of pregnancy was carried out in the first case; however, study of the fetus could not be performed. In the second family, the pregnancy resulted in the delivery of a normal child, as shown by normal phenylalanine level at birth.

Adult↗
PubMed1986

[Manganese in the water supply of the town of Beaucaire: origins and solutions].

Changes in domestic water supply appearance and quality linked with increasing manganese amount and iron at a lesser degree, having been found by the inhabitants of Beaucaire (Rhône Valley), a study was made by chemists, hydrogeologists and biologists to detect the origin. The problem is not specific to this town and can frequently be found in the Saône and Rhône valleys. The results show that we have to deal with an aquifer with semi-captive groundwater whose supply is double: the Rhône and calcareous mountain masses. The low-oxygen waters are enriched, by dissolution from gravel, with manganese and iron which are preferentially fixed on porous and cracked surface elements. The conditions for manganese liberation are connected with the presence of organic matters, bacteria (capable to reduce the manganic compounds) and anaerobiosis. The supply does not seem to be the only cause in the low-oxygen contents; the action of heterotrophic microorganism using organic matter and consuming oxygen, at the groundwater periphery, must be taken into account. Thus the central part of the groundwater system is a reducing environment which allows the modification of the bacterial metabolism towards a ferric and manganic compounds reduction process. The result is the transformation of insoluble manganic and ferric compounds into manganous and ferrous compounds which are liberated into the groundwater.

France↗
PubMed1985

Maple syrup urine disease: two different forms within a single family.

A family is reported in which the index case presented with an acute form of maple syrup urine disease (MSUD), whereas two of her sisters and her father were found to have an almost asymptomatic form of the disease. It is proposed that the members of this family are compound heterozygotes for the classical deficient mutant gene and for a "variant" allele.

Adolescent↗