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Biomedical subjects

D Labie

Publications and source records attributed to D Labie.

At least 91 records · Page 5Linked to original sources
PubMed1977

[Clinical and biological aspects of beta-thalassemia. Apropos of 176 cases].

The study of 176 subjects with beta-thalassemia, associated or not with a hemoglobinopathy, shows great diversity. The hemoglobin C thalassemias are less severe and form a fairly homogeneous group. Sickle cell thalassemia cases have more marked anemia and the disease takes on more varied forms, no doubt because the main mechanism of the anemia, the hyperhemolysis, is influenced by several factors which have a variable effect on the clinical picture. Unassociated thalassemias seem the most polymorphic. Although it seems that in certain foci the beta-thalassemias are fairly stereotyped, this first study shows in Algeria great heterogeneity. All forms are observed both clinically and in the laboratory. Present classifications have not supplied a sufficiently operative model. It is not doubt necessary to await further progress in the laboratory to classify these diseases more precisely.

Adolescent↗
PubMed1977

Hemoglobin Djelfa beta98 (FG 5) Val leads to Ala: isolation and functional properties of the heme saturated form.

Hemoglobin Djelfa beta98 (FG 5) Val leads to Ala is a neutrally substituted unstable hemoglobin, exhibiting the same gross features as hemoglobin Köln beta98 (FG 5) Val leads to Met. In addition to the presence of a deheminized fraction, a heme saturated abnormal hemoglobin was visualized and isolated by high resolution electrofocusing. By functional studies of the fully heminized form, a slightly increased oxygen affinity, an impairment of heme-heme interaction and a decreased response to organic phosphates were demonstrated. These functional perturbations point out the importance of the beta98 invariant valyl residue, in the quaternary contacts. They can account for the poor oxygen delivery of erythrocytes.

Alanine↗
PubMed1977

An unusual case of leukemia with high fetal hemoglobin: demonstration of abnormal hemoglobin synthesis localized in a red cell clone.

A high level of fetal hemoglobin was found in an 8-yr-old boy without any hematologic disorders except for a moderate anemia. The absence of hemoglobin abnormalities in the parents led us to suspect a latent malignant disease that, on follow-up, was confirmed to be myelomonocytic leukemia. Hemoglobin biosynthetic studies provided evidence of unbalanced synthesis of globin subunits by reticulocytes, while the production of non-alpha chains was equal to that of alpha chains in bone marrow cells. The expression of red cell antigen i was increased, while those of I, A, and A1 antigens were found to decrease progressively. Two populations of erythrocytes, A-positive and A-negative, were distinguished and could be separated by differential agglutination. Unbalanced globin chain synthesis, increased fetal hemoglobin, and antigenic changes of the membrane were shown to be restricted to the A-negative population. The biologic data were not entirely consistent with a genuine reversion to fetal erythropoiesis. The question remains of a polychromosomal lesion of either quiescent F cells or adult stem cells.

ABO Blood-Group System↗
PubMed1977

[A new case of hemoglobin J Capetown alpha 92 (FG 4) Arg replaced by gln].

Hemoglobin J Capetown was found incidentally in a patient of french origin suffering from urticaria with delayed pressure oedema. Using a preparative finger-print technique, the structural determination was easy. A functional study of the purified component confirmed the high oxygen affinity of hemoglobin J Capetown and demonstrated a low reactivity for organic phosphates. These results may explain the perturbations observed in the whole blood.

Amino Acids↗
PubMed1976

Isoelectrofocusing: a method of multiple applications for hemoglobin studies.

A microanalytical screening of hemoglobins by isoelectric focusing on acryl-amide gel columns is described. Addition of this technique to our regular analytical procedures revealed many mutants, praticularly some neutral ones which were not resolved by other conventional procedures. Extension of this technique to a quantitative scale permitted rapid isolation of some unstable mutants in an almost pure form ready for functional studies. The natural color of the separated components is often indicative of their nature and in cases like the sulfhemoglobin, Hbs M, they are of diagnostic value. The heme-losing, abnormal, unstable mutants, on the addition of external cyanhemin, take them up and change their isoelectric pH. This is an attractive visible procedure for their diagnosis. From all these results, it appears that isoelectric focusing as a single method brings more information than the other conventional procedures and hence can be considered as a semi-routine investigation for hemoglobin studies before deciding on a much longer procedure.

Fetal Hemoglobin↗
PubMed1976

Isolation of preliminary characterization of a vitamin K dependent peptide from human prothrombin.

A peptide containing the vitamin K dependent Ca2+ binding region of human prothrombin has been isolated by adsorption of the tryptic digest of the native protein on barium citrate. Its aminoacid composition has been determined. The N- and C-terminal residues have been characterized. The obtained results are showing some slight differences with the corresponding bovine peptide. Since they were not strictly identical for two different preparations, the eventuality of a molecular heterogeneity is discussed.

Amino Acids↗
PubMed1976

Ca++ binding properties of human prothrombin.

The binding of Ca++ to human prothrombin has been investigated by equilibrium dialysis. The protein exhibited a positive cooperativity phenomenon for the first three Ca++ bound. Eleven to twelve Ca++ binding sites have been found. They could be differentiated in terms of two classes of sites with respect to their Ca++ affinity: 5 strong binding sites (log Kassoc = 3.9) and 7 weak binding sites (log Kassoc = 2.9). We attempted to determine the Hill coefficient of the strong binding sites responsible for cooperativity. Results have been compared to data previously reported for bovine prothrombin.

Animals↗
PubMed1976

Congenital enzymopenic methaemoglobinaemia. Clinical and biochemical study of a family with three homozygotes.

Three brothers with congenital recessive methaemoglobinaemia without mental retardation were found to be homozygous for NADH diaphorase deficiency. Twelve family members were heterozygous. One of the probands had marked digital clubbing, an unusual feature in this disease. In the probands, the red-cell NADH diaphorase was very low and unstable, whereas in the leucocytes this enzyme was present at a normal level. Isoelectric focusing of haemoglobin in the three probands showed that the alpha-chain was preferentially oxidized spontaneously. This confirms the greater oxidizability of this chain, as already described on isolated chains.

Adolescent↗