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D Labie

Publications and source records attributed to D Labie.

At least 73 records · Page 4Linked to original sources
PubMed1979

Titration curves of polypeptide chains by combined isoelectric focusing-electrophoresis in 8 M urea.

Titration curves of reduced and alkylated polypeptide chains can be successfully performed in 8 M urea-polyacrylamide gel plates by electrophoresis perpendicular to a stationary stack of focused carrier ampholytes. All buffers and thiol reagents with pK values in the range pH 3--10 should be removed, since their pH-dependent ionization affects the migration and apparent pI values of the protein chains. No blurring of the patterns below pH 4.5 is observed, as usually found in titration curves in the absence of urea, thus allowing the direct titration of Glu and Asp residues. It is not possible by the present technique to titrate any group below pH ca. 3 and above pH ca. 10, due to the lack of suitable carrier ampholytes and to a "flooding" phenomenon, with concomitant identical electrophoretic mobility for all protein species, irrespective of their relative pI values and amino acid composition. The "electrophoretic titration curves" thus obtained were well correlated with the overall amino acid composition of the polypeptide chains analyzed.

Electrophoresis, Polyacrylamide Gel↗
PubMed1979

[Glycosylated hemoglobin: résults of 550 cases (author's transl)].

A selective estimation of glycosylated hemoglobin, HbA1C, exclusive of other minor components, is propably one of the best available tests. Such an automated method is proposed, which was experimented in 550 cases. It demonstrates a quite narrow gaussian distribution in controls. In contrast, a large dispersion is observed among long term diabetics, most of them with ocular complications with only a minority of results in the normal range. This is still more evident in case of juvenile diabetes.

Chromatography↗
PubMed1979

Quantitation of hemoglobin A1c: a rapid, automated precision-chromatography technique.

Hemoglobin A1c is increased in patients with diabetes mellitus and its level reflects the status of blood glucose equilibrium over a period of several weeks. The practical use of its estimation was hampered by technical difficulties in investigating large series of samples. In order to apply this examination for routine purposes we describe in this paper acceleration and full automatization of the original chromatographic method allowing quantitation of hemoglobin A1c in 45 min.

Autoanalysis↗
PubMed1979

Structural bases of the inhibitory effects of hemoglobin F and hemoglobin A2 on the polymerization of hemoglobin S.

We have previously found that the inhibitory effect of hemoglobin F (Hb F) on the polymerization of Hb S proceeds via the formation of asymmetrical hybrid tetramers of the type alpha2betasgamma. Examination of the gelling properties of binary mixtures of Hb S and several Hb variants now shows that, among the gamma chain amino acid residues that differ from those of the beta chain, residues gamma80 (EF4) and gamma87 (F3) are at least partly responsible for this inhibition. Furthermore, we find that mixing Hb A2(alpha2delta2) with Hb S strongly inhibits gelling to an extent similar to that seen with Hb S/Hb F mixtures; this inhibition is attributable to amino acid differences between the delta and beta chain sequences at positions delta22 (B4) and delta87 (F3). Therefore, residues 22, 80, and 87 of the beta chain appear to be involved in intermolecular contact sites that stabilize the deoxy Hb S polymers.

Amino Acid Sequence↗
PubMed1979

Hematological and hemoglobin synthesis studies in a family with deltabeta-thalassemia trait.

A Basque Spanish family with heterozygous deltabeta-thalassemia is described. Patients with this anomaly usually present hematological findings observed in classical beta-thalassemia, but clinical conditions and unbalanced chain synthesis are less severe. Our propositus, however, presented clinical and biosynthetic data similar to those described in thalassemia intermedia. A family study was also performed.

Adolescent↗
PubMed1979

[Hemoglobin J Amiens beta 17 (A 14) Lys replaced by Asn. Coincidence of a functionally silent new abnormal hemoglobin and a polycythemia vera (author's transl)].

A new abnormal hemoglobin, Hb J Amiens beta 17 (A 14) Lys replaced by Asn, has been discovered during the exploration of a recent polycythemia in a 65-year-old patient of Spanish extraction. Oxygen affinity of washed red blood cells was found to be normal at pH 7.13 (P 50 = 30.0 mmHg, N = 29.5 +/- 1). Cooperativity is unchanged, and no instability was detected. From this study, it is concluded that there is no relation between this functionally silent hemoglobin and the polycythemia. In fact, the recent appearance of the polycythemia, the involvement of the other blood cell lines, particularly the thrombocytosis, the high score of leukocyte alkaline phosphatases, and the results of the bone marrow biopsy led to the diagnosis of polycythemia vera.

Aged↗
PubMed1979

[Hemoglobin G Coushatta (beta 22 (B4) glu leads to ala) in Algeria: an homozygous case].

In this paper, we report the first observation of Hb G Coushatta (beta 22 (B4) Glu leads to Ala) in North Africa. An homozygous case was discovered and studied. The structural abnormality was characterized by using S. aureus protease. The analytical methods capable of distinguishing these hemoglobins from D Punjab, D Ouled Rabah and D Iran which have similar hemoglobin electrophoretic mobilities will be discussed.

Adolescent↗
PubMed1978

[Hemoglobin Pyrgos beta 83 (EF 7) Gly leads to Asp in a Malian: structural identification and functional properties (author's transl)].

The second observation of hemoglobin Pyrogos is reported. This abnormality was initially described in a Greek family, in our case it concerns an African negro originating from the Republic of Mali. The abnormal hemoglobin was without clinical or hematological consequences. The structural defect is a substitution of an Asp for a Gly in the immediate vicinity of lysine beta 82. This leads to a large inhibition of the corresponding tryptic cleavage and therefore to difficulties in the determination of the mutation. A second feature is a slight modification occurring near one of the 2.3 DPG binding site. As a consequence, the regulatory effect of this organic phosphate is smaller in the purified and stripped component than on hemoglobin A.

Amino Acid Sequence↗
PubMed1978

Genetic and biosynthetic studies of families carrying hemoglobin J alpha Mexico: association of alpha-thalassemia with HbJ.

Hemoglobin J Mexico, an alpha chain mutant, was studied in eight unrelated Algerian families. The quantities of the abnormal hemoglobin in 116 subjects are trimodally distributed: 55% in homozygotes, 31% and 38% in heterozygotes. Both hematological data and the alpha/beta chain biosynthetic ratio are normal in heterozygotes with 31% Hb J and in homozygotes. In contrast, the MCV and MCH as well as the alpha/beta biosynthetic ratio are slightly reduced in heterozygotes with 38% Hb J and in their relatives carrying Hb A. The elevated expression of alphaJ chains in heterozygotes with 38% Hb J may be due to an alpha thalassemia gene trans to the alphaJ locus.

Algeria↗