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Biomedical subjects

J Riou

Publications and source records attributed to J Riou.

At least 55 records · Page 3Linked to original sources
PubMed1990

A new hemoglobin variant found during investigations of diabetes mellitus: Hb Pavie [alpha 135 (H18) Val----Glu].

Hb Pavie [alpha 135 (H18) Val----Glu], found during HbA1c measurement in a patient of Italian origin investigated for diabetes mellitus, exemplifies how the presence of an abnormal hemoglobin interferes with the measurement of glycated hemoglobin. This variant hemoglobin migrates as Hb A1c on polyacrylamide gel isoelectric focusing (IEF) and therefore hindered the estimation of glycated hemoglobin by this method. By ion-exchange high-performance liquid chromatography (IE-HPLC) Hb Pavie was eluted as a shoulder of the major component and the corresponding glycated fraction together with Hb A1b. Hb Pavie was purified in order to determine how its functional properties may modify red cell survival. The only functional abnormality observed was a slight decrease of the oxygen affinity, and therefore the total amount of glycated hemoglobin was not expected to be decreased by a shortening of the red cell survival.

Amino Acid Sequence↗
PubMed1990

Hemoglobin Dhonburi alpha 2 beta 2 126 (H4) Val----Gly: a new unstable beta variant producing a beta-thalassemia intermedia phenotype in association with beta zero-thalassemia.

While investigating the mechanism of a beta-thalassemia intermedia phenotype in a 34 year old Thai male, a new Hb variant beta 126 Val----Gly named Hb Dhonburi was discovered. Genetic and structural studies revealed the existence of a beta zero-thalassemia genotype in association with the beta variant. The new variant is unstable but exhibits normal oxygen binding properties. Hb Dhonburi was also discovered in the mother of the propositus in association with Hb E.

1-Propanol↗
PubMed1989

Hemoglobin Villejuif [beta 123(H1) Thr----Ile]: a new variant found in coincidence with polycythemia vera.

A new abnormal hemoglobin, Hb Villejuif [beta 123(H1) Thr----Ile] has been discovered during the exploration of a polycythemia in a 87-year-old patient of French origin. The isoelectric focusing of the lysate revealed the presence of a variant hemoglobin with an isoelectric point very close to that of HbA. The oxygen binding properties of the patient's red blood cells being normal, it was clear that the polycythemia was not a consequence of the presence of this hemoglobin. In fact, the red blood cell morphology and the involvement of the other blood cell lines, demonstrating excessive hemopoiesis, led to the diagnosis of polycythemia vera.

Aged↗
PubMed1989

Hb Fontainebleau [alpha 21(B2)Ala----pro], a new silent mutant hemoglobin.

Hb Fontainebleau [alpha 21(B2)Ala----Pro] was found in a family of Italian origin. This new variant has electrophoretic properties identical to those of Hb A with the exception of isoelectrofocusing in which it migrates like Hb A1c. The introduction of a prolyl residue at the beginning of the B helix in the alpha chain does not lead to a change in the stability or oxygen binding properties of the hemoglobin molecule.

Adolescent↗
PubMed1988

Hemoglobin Brest [beta 127 (H5)Gln----Lys] a new unstable human hemoglobin variant located at the alpha 1 beta 1 interface with specific electrophoretic behavior.

Hb Brest [beta 127 (H5)Gln----Lys] is a new unstable variant located at the alpha 1 beta 1 interface at the same position as Hb Complutense [beta 127(H5)Gln----Glu]. In each of these, the substitution produces a distinct alteration in charge, yet both variants move with Hb A in conventional electrophoresis. This peculiar electrophoretical behavior may be due to the molecular position of the modified residue, which is deeply buried inside the tetramer.

Amino Acid Sequence↗
PubMed1987

Further characterization of Hb Henri Mondor or alpha 2 beta 2(26)(B8)Glu----Val.

A second case of Hb Henri Mondor is reported. The subject, homozygous for Hb Henri Mondor, is of Algerian origin. The electrophoretical behavior and structural characterization are given and discussed. Hb Henri Mondor, which is characterized by the replacement of the lysine residue in position beta 26, as is the case for Hb E, has normal functional properties and is normally expressed.

Amino Acids↗
PubMed1987

[Hemoglobin Boumerdès alpha 2(37) (C2) Pro----Arg beta 2: a new variant of the alpha chain associated with hemoglobin S in an Algerian family].

We report the first case of Hb Boumerdes, an alpha chain variant alpha 2(37) (C2) Pro----Arg beta 2, in an Algerian family. The propositus was also homozygous for the sickle cell gene. The abnormal hybrid Hb alpha 2Boum. beta 2S had an electrophoretic mobility on cellulose acetate pH 8.7 electrophoresis between those of Hb S and Hb A2. Its expression was about 16%. The alpha 2Boum. beta 2A fraction has a mobility between those of Hb F and Hb S. The effects of this mutation on Hb oxygen affinity and deoxy Hb S polymer formation were not studied. The propositus' sickle cell phenotype was benign.

Adolescent↗
PubMed1986

[Abnormal hemoglobins screened in Tunisia].

We report the complete data we have collected concerning abnormal Hb in Tunisia, and their local repartition. The highest frequencies are observed in the North-West countries.

Genetic Testing↗
PubMed1986

[Screening for hemoglobinopathies and G6PD deficiencies in Morocco].

Screening for abnormal hemoglobins and G6PD deficiency was conducted in adult and new born Maroccans from Casablanca. The results presented deal with HbS and HbC traits, alpha, gamma, and delta mutations, the presence of detectable amount of Hb Bart's and the G6PD deficiency frequency.

Adult↗
PubMed1985

Structural and functional studies of hemoglobin Poissy alpha 2 beta 2(56) (D7) Gly----Arg and 86 (F2) Ala----Pro.

Hemoglobin Poissy alpha 2 beta 2(56) (D7) Gly----Arg and 86 (F2) Ala----Pro, is a new variant of the beta chain with two substitutions within the second exon of the corresponding gene. The electrophoretic mobilities are identical to those of Hb Hamadan alpha 2 beta 2(56) (D7) Gly----Arg as is the fingerprint of the tryptic hydrolysate of the two abnormal beta chains. The second substitution beta 86 Ala----Pro was detected by high-pressure liquid chromatography. Hb Poissy has a threefold increase in oxygen affinity with low Hill coefficient and diminished Bohr effect, which are restored to normal upon addition of 2,3-bisphosphoglycerate. Since the functional properties of Hb Hamadan (beta 56 Gly----Arg) have been described as normal, the abnormal function of Hb Poissy may be attributed to the beta 86 (F2) Ala----Pro substitution. Hb Poissy exhibits a mild instability and a greater reactivity of the thiol groups of the beta 93 (F9) Cys residues in the deoxy form than does Hb A. The oxidation rate of Hb Poissy is biphasic indicating a large inequivalence between the alpha and beta hemes. Thereafter NMR studies demonstrated that the beta 86 Ala----Pro substitution produces a displacement of the F helix closer to the heme plane and a large increase in the dynamic fluctuations of the tertiary structure on the proximal side of the beta hemes. These results lead to the conclusion that the beta 86 Ala----Pro substitution produces a destabilization of the F helix extending downwards to the FG corner and altering both the beta hemes and the alpha 1 beta 2 contacts.

Amino Acids↗