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F Galacteros

Publications and source records attributed to F Galacteros.

175 records · Page 10Linked to original sources
PubMed1981

Excess alpha chains are lost from beta-thalassemic reticulocytes by proteolysis.

During incubation of reticulocytes from patients with beta-thalassemia, after labeling of the hemoglobin with radioactive amino acids, the excess alpha chains are gradually lost from the cells. The aim of this study was to investigate the mechanism of this phenomenon. A system was developed in which reticulocytes from beta-thalassemia patients are labeled with [3H]leucine, washed several times in nonradioactive medium, and then incubated in the same medium containing puromycin added in order to stop further protein synthesis. The results have clearly shown that excess alpha chains are gradually degraded by proteolysis. N-ethylmaleimide or epsilon-aminocaproic acid inhibited the proteolysis of free alpha chains. The addition of either ATP or hemin did not change the rate of alpha chain degradation. The time required to degrade 50% of the pool of free alpha chains was directly dependent on the initial value of this pool. This finding suggests the absence of a significant individual variation in the ability to proteolyse free alpha chains.

Adenine↗
PubMed1981

Beta-thalassemia and sickle cell disease in culture of early erythroid precursors: hemoglobin synthesis and ultrastructural study.

Hemoglobin synthesis was studied in culture of early erythroid precursors (BFU-E) from the blood of nine patients exhibiting sickle cell anemia and of 14 with various types of beta-thalassemia. The results concerning gamma gene expression and plating efficiency in heterozygotes for sickle cell anemia were similar to those of normal adults (gamma/alpha = 0.05; 65 BFU-E colonies/10(6) plated cells) while, in contrast, homozygotes for sickle cell disease exhibited average values higher than the controls (gamma/alpha = 0.18; 80 BFU-E colonies/10(6) plated cells). However, the results were very heterogeneous from one subject to another. In heterozygotes for beta-thalassemia, gamma gene expression and plating efficiency were both slightly higher than those for normal individuals (gamma/alpha = 0.095; 129 BFU-E colonies/10(6) plated cells). In patients homozygous for beta-thalassemia, a marked increase in plating efficiency and gamma-chain synthesis was constantly observed (gamma/alpha = 0.41; 221 BFU-E colonies/10(6) plated cells). The high proportion of gamma chain synthesis was not related to a positive selection of F cells, since the gamma/alpha ratio remained constant during the in vitro erythroid maturation. Furthermore, a major increase in free alpha chain proteolysis can be ruled out, since the beta/alpha ratio was of the same order of magnitude in culture and in freshly drawn cells. Thus, the increased Hb F synthesis in vitro was the consequence of a true stimulation of gamma gene expression, which permitted partial correction of the globin chain imbalance. Ultrastructural studies in two homozygotes for beta-thalassemia showed a marked decrease in the abnormalities of the erythroblasts derived from erythroid precursors in vitro in comparison to those from fresh bone marrow samples. In particular, Heinz bodies were much less numerous and a high frequency of mature erythroblasts and reticulocytes was observed in culture. These results support the view that, in sickle cell anemia and beta-thalassemia, a high potential for gamma gene expression exists and can be expressed in culture.

Anemia, Sickle Cell↗
PubMed1981

[Clinical studies of the erythrocytosis produced by a new hemoglobin with oxygen affinity : Hb Hôtel-Dieu alpha 2A beta 2 Asp replaced by Gly (author's transl)].

A new case of erythrocytosis associated with a high oxygen affinity hemoglobin is reported : the substitution of beta 99 of aspartic acid by glycine, characterized this abnormal hemoglobin, named "hemoglobin Hôtel-Dieu". An important associated smoking habit, probably responsible of an abnormal lung X-ray and of a disturbed CO transport, contributed to increase the difficulty of diagnosis. Familial inquiry, the search of an abnormal hemoglobin by standard or isoelectrofocusing electrophoresis, and the 2,3-DPG assay should be systematically performed in case of polycythemia in young people or in the absence of obvious aetiology. A corpuscular abnormality can be thus detected in about 10 p. cent of such polycythemias.

Adult↗
PubMed1980

Disappearance of Hb F and i antigen during the first year of life.

In order to investigate whether a common control mechanism is involved in the diminution of i antigen expression and that of Hb F content in human erythrocytes during the postnatal period, we compared changes in 72 normal infants aged from 0 to 12 months. The proportion of hemoglobins (Hb F, Hb A, Hb A2) and the quantitation of "i" antigen were determined on the total population of red blood cells. In addition, the percentage of individual cells containing Hb F or "i" antigen or both (F cells, "i" cells, and F + "i" cells) were evaluated by using a rhodamine-conjugated anti-Hb F and a fluorescein conjugated anti-system on the same smear preparation. The results provided by the two most sensitive techniques (F cell counting and "i agglutinability) indicated that the curves of disappearance of Hb F and "i" antigen along the 12 first months after birth were identical. A strong correlation (r = 0.97, P < 0.0001) existed between the percentage of F cells and "i" antigen expression. In addition, the progressive increase in Hb A2 concentration was inversely correlated firstly with the proportion of Hb F and second with the expression of the "i" antigen. These results suggest that the switch from fetal to adult hemoglobin and the transformation of "i" antigen expression occurring during the first year following birth are governed by a common control mechanism.

Aging↗
PubMed1980

Cord blood screening for hemoglobin abnormalities by thin layer isoelectric focusing.

Hemoglobin variants can be successfully identified in cord blood samples. The methods most commonly used include cellulose acetate (CAC) and citrate agar (CAG) electrophoresis. Recently thin layer isoelectric focusing (TLIF) has been shown to be an excellent method for identifying hemoglobin variants. To determine the applicability of TLIF for cord blood screening, we compared the results of 835 samples obtained by TLIF with that obtained by CAC, CAG, and the combination of both CAC and CAG. In 100 of these samples we detected an abnormal hemoglobin pattern using TLIF. In contrast, we detected only 80 abnormal samples by CAC, 70 by CAG, and 80 by using the combination of CAC and CAG. Due to the increased resolution provided by TLIF, we correctly diagnosed two sickle cell trait samples by TLIF that were incorrectly suspected to be homozygous for sickle cell disease by CAC and CAG. We identified 41 samples containing Bart's hemoglobin by TLIF in contrast to only 21 using CAC and 14 using CAG. The time and cost of TLIF was comparable to that using the combination of both methods. We, therefore, conclude that TLIF is the method of choice for cord blood screening.

Anemia, Sickle Cell↗
PubMed1977

[Protein assay by immunoprecipitation with Centrifichem centrifugal analyser].

The authors present an automatic technic of estimation of ten serum proteins (albumin, alpha-antitrypsin, orosomucoid, alpha-1-macroglobulin, haptoglobin, C'3 complement, transferrin, IgM, IgG, IgA) by immunoopacimetry on a Centrifichem centrifugal analyser. This technic is derived from an immunonephelometric method, with the following differences: --the use of two concentrations of polyethylene glycol permitting one to obtain for all proteins, a constant levelling-out of the reaction within 3 minutes; --by a first reading at 3 seconds avoiding the prior determination of blank reagents and sera; --by the use of two dilutions of serum permitting calculation of all concentrations. The results are reproducible and are satisfactory: 95% of the coefficients of variation are less than +/- 5% in the case of all the proteins. The correlation with IDR is good. The coefficients vary from 0.91 to 0.99.

Autoanalysis↗
PubMedDate not supplied

[A case of a combination heterozygote with hemoglobin K Woolwich and hemoglobin C (Hb Kw/HbC) discovered in Bobo-Dioulasso (Burkina Faso)].

During a study on malaria in pregnant women in Burkina Faso, the authors gave a particular attention to the hemoglobin of a mother and her new-born child (blood of cord) and they noticed an hemoglobin migrating before the HbA which was identified by isoelectric focusing (IEF). The child is a composite HbK/HbC heterozygote. A survey was carried out to check the transmission of such a K Woolwich hemoglobin within the family of the mother. Out of 40 people, 17 got HbKw. A noticeable anemia was found in HbKw/HbC heterozygote. The authors tried to identified a possible thalassemia. There was little probability for an association of a minor alpha-thalassemia in the absence of Bart's hemoglobin in the blood of the cord (IEF test) and there was no associated beta-thalassemia.

Adult↗
PubMedDate not supplied

[Evaluation of the incidence of glucose-6-phosphate dehydrogenase deficiency in children with sickle cell anemia in Brazzaville (Congo)].

Following a survey on prevalence of sickle-cell anemia in Brazzaville's Region, the authors surveyed, in the same population, the incidence of Glucose-6-Phosphate dehydrogenase deficiency (G6PD) and the sharing of enzyme deficiency among sickle cell anemia patients (AA). This survey was carried out among children from 0 to 3 years of age, thanks to a very close collaboration between the Laboratory of bio-chemistry of the Faculty of Sciences, Maternity Hospitals of Blanche-Gomez, Makelekele, and Maternity Ward of the Brazzaville General Hospital. 214 children were examined in these Health Units. Blood samples were analysed by the thin layer isoelectric focusing technics. 128 children were safe from hemoglobin abnormalities, 44 had heterozygous and 42 homozygous sickle cell anemia, i.e. 19.6 p.c. of the total population surveyed. Measurement of the G6PD activity in these children revealed that 25.8 p.c. of the AA had an incomplete deficiency in G6PD, 31.8 p.c. of the AS and 45.2 p.c. of the SS were G6PD deficient (table I). These results, although fragmentary, demonstrate that G6PD deficiency does exist in the Congolese population, and that this enzyme deficiency might be more frequent in the carriers of sickle cell trait, evaluated by the authors at 22.4 p.c. of the population.

Anemia, Sickle Cell↗
PubMedDate not supplied

[Anatomical and pathophysiological bases of renal disorders in sickle cell syndrome patients and carriers of the trait].

The process of intraerythrocytic gelling of haemoglobin S is exacerbated by physiochemical and circulatory conditions which dominate in the renal medulla. In the first few years of life, the sickle cell disturbance is reversible by exchange transfusions. At about the age of 15, this is no longer reversible in homozygotes and is replaced by anatomical lesions which gradually destroy the renal functional capacity for concentrating urine, for excreting H+ and K+ ions and for secreting uric acid. The crises are acute rheological events which temporarily accentuate these disorders which appear to be the combined result of hyperviscosity and vascular occlusions. As the occurrence of hematuria and urinary infections is necessarily organically linked to the parenchymatous lesions, their frequency and severity pose great problems concerning treatment. Recent works emphasize the frequency and severity of renal disorders in sickle cell patients during the period of life which is over 30 years. A preventive disposition must be maintained from childhood: restriction of the use of nephrotoxic drugs, reduction of the frequency of crises, dehydration and urinary infections, and subsequently regular observation of kalemia, uricemia and proteinuria.

Adolescent↗
PubMedDate not supplied

[Radiological appearance of bone manifestations in acute drepanocytic syndromes in adults (author's transl)].

The authors describe 18 cases of this syndrome and emphasize that attenuated clinical forms of homozygotic drepanocytosis exist, as well as, in a more general manner, in acute drepanocytic syndromes. The disease may first appear in adult life. The frequency of radiological signs in the spine has to be stressed, and the authors emphasize the diagnostic value of the "staircase" deformation of the vertebrae, representing the sequelae of bone ischemic lesions. The discovery of this radiological sign suggested the diagnosis of a hemoglobinopathy in two cases. This attenuated form of the disease presents the same risks of thromboses but these complications can be reduced by prophylactic treatment. This underlines the need for early detection and radiological investigation can be of great assistance.

Adolescent↗
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↗