Biomedical subjects

D Bachir

Publications and source records attributed to D Bachir.

62 records · Page 4Linked to original sources

PubMed1985

Red cell membrane sialoglycoprotein beta in homozygous and heterozygous 4.1(-) hereditary elliptocytosis.

Sialoglycoprotein beta, a minor sialoglycoprotein of the red cell membrane, was studied in homozygous and heterozygous 4.1(-) hereditary elliptocytosis, a variety of hereditary elliptocytosis characterized by total or partial absence of protein 4.1. Erythrocytes were treated with the periodic acid-NaB3H4 procedure. Following polyacrylamide gel electrophoresis in the presence of SDS, labelled sialoglycoproteins were revealed by fluorography. (i) In the ghosts from the 4.1(-) homozygote, sialoglycoprotein beta was sharply decreased. It is not sure whether the residual material is sialoglycoprotein beta itself, or a distinct sialoglycoprotein migrating in the same place. In long exposure fluorograms, sialoglycoprotein gamma (a sialoglycoprotein related to sialoglycoprotein beta) also turned out to be reduced. In the homozygote's Triton-shells, sialoglycoprotein beta and gamma appeared completely absent. (ii) In the 4.1(-) heterozygote, sialoglycoprotein beta appeared slightly reduced, whereas sialoglycoprotein gamma appeared normal. Both of these proteins were extracted in seemingly normal amounts in the Triton-shells. These observations bring further support to the view that there is an interaction between skeletal membrane protein 4.1 and sialoglycoprotein beta, that is additional to other interactions between the former protein and the lipid bilayer and/or other transmembrane proteins.

Adolescent↗

PubMed1985

Alpha globin gene triplication in severe heterozygous beta thalassemia.

In an Algerian family, three sibs with an unusually severe heterozygous beta-thalassemia and two sibs with a typical heterozygous beta-thalassemia were found. Both conditions were transmitted vertically. Globin chain synthesis and DNA restriction enzyme analysis showed that the unusual severity of heterozygous beta-thalassemia observed in this family is related to an overproduction of alpha-globin chains originating from an alpha-globin gene triplication.

Adolescent↗

PubMed1985

The heterozygous form of 4.1(-) hereditary elliptocytosis [the 4.1(-) trait].

Using clinical, morphological, genetic, and biochemical criteria, we studied ten white and North African families with hereditary elliptocytosis (HE). In four families, elliptocytic individuals displayed a highly significant reduction of band 4.1, which was recorded using two electrophoretic procedures. The 4.1a/4.1b ratio was also significantly reduced, as is usually observed in suspensions enriched in young red cells. This form of HE was invariably associated with the following characteristics: absence of clinical signs; numerous, smooth and well-elongated elliptocytes; dominant transmission; and, when investigated, normal osmotic fragility. Its frequency, among all forms of HE, is about one third as a first estimate, at least in whites and North Africans. In the other six families studied, elliptocytic subjects presented normal 4.1 bands. Again, the 4.1a/4.1b ratio was decreased, reflecting the red cell age-dependent changes in these two components. In three of these families, elliptocytosis was accompanied by clinical signs of variable intensity, and the mode of inheritance could not be unequivocally determined. Therefore, HE with a partially reduced band 4.1 defines a homogeneous variety of HE that can be isolated from other forms of HE. We suggest that it be termed the 4.1 (-) trait, so as to correspond with a previously proposed terminology.

Adolescent↗

PubMed1984

Sickle cell beta-thalassaemia compared with sickle cell anaemia in Algeria.

Clinical, haematological and biochemical features in 42 subjects with S-beta thalassaemia (31 subjects with S-beta thalassaemia and 11 subjects with S-beta+ thalassaemia); and in 42 with homozygous sickle cell disease were compared. Persistent splenomegaly was more common and painful crises less common in the S-beta thalassaemia group. Total Hb was higher and reticulocyte count lower in S-beta+ thalassaemia than in S-beta thalassaemia or SS disease. Microcytosis was marked in the S-beta thalassaemia group while the MCV was normal in sickle cell anaemia. Hb F was significantly higher in the S-beta thalassaemia group, without any influence on the severity of the disease. Many features suggest that sickle cell thalassaemia is more severe in Algeria than in Negro subjects and similar to the disease in Italian patients.

Adolescent↗

PubMed1984

Indirect evaluation of a gene frequency: calculation of beta-thalassemia frequency in Algeria based on associated hemoglobin variants frequency.

The gene frequency (q) of beta-thalassemia (T) is more difficult to evaluate directly than the frequency of hemoglobin variants (V), Hb S and Hb C being the most frequent ones in Algeria. Among 150 subjects with a phenotype V, we identified 76 compound heterozygotes VT(0) (T(0) = beta(0)-thalassemia) and 74 homozygotes VV: qT(0) is therefore practically equal to qV. Calculation based on the investigation of 54 subjects detected during the same period (33 VT among which 23 VT(0) and 21 TT among which 9 T(0) T(0) yields qT = 1.43 qT(0) = 1.43 qV. According to Cabannes [1965], qV is equal to 0.0113, qT is 1.43 X 0.0113 = 0.0162. This indirect method, based on investigation of patients, gives a less precise evaluation of gene frequency than a direct method based on large population screening. This evaluation, however, is sufficient to estimate the incidence of beta-thalassemia and its impact from a public health point of view.

Algeria↗

PubMed1982

Kinetic alterations of the red cell membrane phosphatase in alpha- and beta-thalassemia.

We studied the red cell membrane neutral phosphatase, which is part of the Na+K+ ATPase, in several types of oxidative hemolytic anemias. We used an artificial substrate, the p-nitrophenylphosphate. In controls and in patients heterozygous for various unstable hemoglobins (Hb Hope, Hb Köln, or Hb Hammersmith), the kinetics were of the Michaelis-Menten type. On the contrary, in nearly all patients with alpha- or beta-thalassemia, the kinetics displayed an abnormally biphasic character. The apparent Michaelis constant (KMapp) was significantly decreased. The biphasic character correlated with the imbalance of globin chain synthesis. The beta-mercaptoethanol markedly increased Vmax in controls, but had little effect on the biphasic kinetics. Omission of K+ abolished the biphasic kinetics. The abnormal kinetics failed to appear with another artificial substrate, the 4-methylumbelliferylphosphate, nor did it appear with ATP, the natural substrate. In vitro, H2O2 treatment of normal and thalassemic red cells was unable to induce or exaggerate, respectively, the biphasic kinetics, but generated alterations of a different nature. We suggest that the various kinetic alterations of the phosphatase in thalassemic syndromes originate from the imbalance of globin chain synthesis. However, the involvement of an oxidative process remains to be demonstrated.

Erythrocyte Membrane↗

PubMed1981

Hemoglobin Bart's in Northern Algeria.

The hemoglobin patterns of 293 cord bloods from Northern Algeria were examined by electrophoresis on cellulose-acetate strips. A fast-moving component, identified as Hb Bart's, was found in about 10% of the cases. The levels of Hb Bart's ranged from 0.1 to 10% of the total hemoglobin. There was a significant correlation between the Hb Bart's levels and the decrease in MCV. The relative rates of globin chain synthesis measured by 3H-leucine incorporation was estimated in 15 cord bloods. It was found imbalanced in the 5 cord bloods which contained more than 0.5% Hb Bart's. These findings suggest that elevated Hb Bart's levels in the Algerian population are due to the presence of alpha-thalassemia.

Algeria↗

PubMedDate not supplied

[Hip dysplasia, a complication of sickle cell anemia].

Eighty-four hips of sickle cell anemia patients were followed up during adulthood after the occurrence during childhood of avascular necrosis of the femoral head. Roentgenograms showed residual dysplasia at completion of growth in a substantial number of cases: coxa magna was found in 11 hips, coxa plana or loss of capital sphericity in 53 hips, and true osteochondritis in 3 hips. Only 20 hips exhibited normal morphological features at completion of growth. Anomalies were found not only in the proximal femur but also in the acetabulum which was altered in 14 hips (inadequate lateral coverage in 8 hips and protrusion in 6). Roentgenological changes suggested that the acetabular alterations were due to triradiate cartilage lesions directly produced by the blood disorder rather than to the effects of the femoral alterations. The anomalies seen also suggested that the adverse effects of sickle cell anemia on growth involve not only epiphyseal ossification centers but also growth plates.

Acetabulum↗