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Biomedical subjects

F Galacteros

Publications and source records attributed to F Galacteros.

At least 163 records · Page 9Linked to original sources
PubMed1983

Factors involved in cell adhesion to vascular endothelium.

The adhesion of blood cells to endothelium can be studied in vitro using human endothelial cells in culture. This experimental model and radiometric techniques provide us with a simple system to quantify the adhesion of blood cells to endothelium. Normal human granulocytes isolated by density gradient adhere to normal endothelial cells in a proportion of 25%. Human promyelocytic cells (HL 60) induced by retinoic acid into mature cells adhere as well as normal granulocytes while the noninduced adhere poorly to endothelium. A small percentage of normal red cells attach to endothelial cells while red cells from patients with sickle cell anemia or diabetes mellitus have a significantly increased adhesion to endothelial cells (P greater than 0.001). This adhesion is statistically correlated with the extent and severity of vascular complications in diabetes mellitus (P less than 0.05). The addition of fibrinogen significantly increased (P less than 0.01) the adhesion of normal red cells, red cells from patients with sickle cell anemia or diabetes mellitus while gamma-globulins did not modify adhesion. Fibronectin potentiated the adhesion of normal red cells.

Anemia, Sickle Cell↗
PubMed1983

Fibrinogen, a modulator of erythrocyte adhesion to vascular endothelium.

The high incidence of thrombosis in inflammatory states and previous reports of increased adhesion of erythrocytes to endothelial cells in diabetes mellitus and sickle cell anemia prompted us to study the effect of fibrinogen and fibronectin on erythrocyte-endothelial interactions. Purified human fibrinogen enhanced erythrocyte adhesion in a concentration-dependent fashion. Erythrocytes from normal subjects, diabetics, and patients with sickle cell anemia were studied. The ratio between the adhesion of normal red cells in a 4 gm/L fibrinogen to adhesion in buffer without fibrinogen was 3.6 (p less than 0.001). Fibronectin also increased red cell adhesion but the effect was less than that of fibrinogen. The addition of fibronectin to fibrinogen limited the enhancing effect of fibrinogen, although the effect of the mixture was greater than that of fibronectin alone (p less than 0.05). Anti-von Willebrand factor and antifibronectin, which react with endothelial cells, also produced an increase in erythrocyte adhesion. The potentiation of adhesion by fibrinogen was also seen in experiments using red cells from patients with sickle cell anemia or diabetes mellitus. These observations provide possible mechanisms for the involvement of plasma proteins in vascular occlusive diseases.

Adult↗
PubMed1982

Structural study of hemoglobin Knossos, beta 27 (B9) Ala leads to Ser. A new abnormal hemoglobin present as a silent beta-thalassemia.

A new electrophoretically silent hemoglobin variant is described that produces the classical phenotype of beta thalassemic intermedia in association with beta thalassemia trait. This variant has the expression of a silent beta thalassemia trait. The abnormal hemoglobin was detected by acid-urea-Triton-acrylamide electrophoresis and further demonstrated by isoelectric focusing. The amount of the variant in carrier is approximately 30% of the total hemoglobin. No instability was found. Absence of hemoglobin A in the propositus blood facilitated structural studies. Peptides maps were normal but analysis of individual peptide spots showed an Ala leads to Ser substitution in the beta T3. This variant has been previously called Hb Knossos (beta 27 (B9) Ala leads to Ser).

Amino Acids↗
PubMed1982

[Use of a new rheometer for the study of the filtrability of a suspension of sickled red cells as a function of PO2].

The filtration time of a small volume (0.1 ml) of red cell suspension from normal (AA), heterozygous (AS) and homozygous (SS) subjects for sickle cell disease was investigated as a function of PO2 The curve of filtration time of AS and SS red cell suspensions was biphasic. At high values of PO2, the progressive reduction of filtrability of sickle cell suspensions with decreasing PO2 occurred without new change in morphology of most of the cells. In contrast, at lower PO2 the apparent filtrability was improved and the cells were sickled." However the red blood cells were retained by the filter and the "solvent" filtrability was improved because rigid and highly deformed sickled cells did not clogged completely the pores of the filter. This study allowed to distinguish a new concept of apparent filtrability for red blood cells in sickle cell disease.

Anemia, Sickle Cell↗
PubMed1982

A new silent hemoglobin variant in a black family from French West Indies, hemoglobin Le Lamentin alpha 20 His replaced by Gln.

A new abnormal hemoglobin Hb Le Lamentin alpha 20 (B1) His replaced by Gln was discovered during a survey of cord blood from the French West Indies (Martinique). This variant displays an electrophoretic pattern similar to that of Hb A but can be isolated by isoelectric focusing (IEF) and Biorex 70 chromatography. Family studies showed the presence of this hemoglobin variant in the father and in two of his three children. Hematological data from the carriers were normal.

Adult↗
PubMed1982

Binding of 21 thiol reagents to human hemoglobin in solution and in intact cells.

The reactivity of the cysteine-beta 93 residue of human hemoglobin was investigated in order to define the optimal structure of potential antisickling agents. The properties of 21 thiol reagents were compared with regard to (a) their binding rate to hemoglobin in solution and within intact cells; (b) the modification of the oxygen dissociation curve of intact cells and (c) the effect on methemoglobin formation in solution or within intact cells. The results show the very different behaviors of these reagents.

Adult↗
PubMed1982

The screening of alpha- and beta-globin chain variants with isoelectric focusing.

A simple isoelectric focusing technique is presented for the screening of alpha- and beta-globin chain variants on polyacrylamide gel in the presence of 8 M urea. No detergent was used. Variants focused at discrete pH values, depending on the charge variation (-2, -1, 0, +1 or +2) introduced by the mutation. A linear relationship was evidenced between the charge variation and the shift of the apparent isoelectric point of the variants. The practical interest of this procedure is illustrated.

Electrophoresis, Polyacrylamide Gel↗
PubMed1982

[Methemoglobinemia and hemolytic anemia induced by Disulon].

Seven patients ingested (2.5 mg/kg) daily dapsone. Their serum samples were analyzed daily during the first week by spectrophotometry for methaemoglobinemia and weekly blood samples for red blood cells, reticulocytes count and haptoglobin level. The acetylator phenotype of each patient was estimated on the capacity to acetylate isoniazid. Methaemoglobinemia was always observed within the 48 hours after drug intake. The dapsone induced anemia was moderate being maximum between day 25 and 40 after the beginning of treatment. Reticulocytemia appeared in the second week and haptoglobin levels decreased between day 5 and 8 of therapy in 5 patients and at day 15 for the two others. The seven patients are divided in 4 rapid acetylator and 3 slow acetylator. The acetylator phenotype was not correlated with methaemoglobin, haptoglobin levels or RBC counts.

Acetylation↗
PubMed1981

[Detection of haemoglobinopathies at birth, using isoelectric focalization (author's transl)].

The incidence and nature of haemoglobinopathies were investigated at birth in Martinique, where 4635 samples of umbilical cord blood were examined. Conventional blood values were determined, and a new, extremely simple and highly selective test was performed: isoelectric focalization. Abnormalities were found in 14.3% of blood samples, viz: A/S 7.25%, A/C 3.17%, S/S 0.17%, S/C 0.24%, C/C 0.04%, other mutations 0.63% alpha-thalassaemia minor (alpha 1-thal) 1.72% and isolated microcytosis 1.01%. Unusual abnormalities included 7 different mutations of the 4a-chain, 3 of the beta-chain and 3 of the gamma-chain. The clinical and epidemiological importance of such investigations is emphasized.

Fetal Blood↗
PubMed1981

Frequency of human A gamma 75Thr globin chain in a population from Tunisia.

Cord blood samples, collected at Sousse and Monastir, from Tunisian newborns were focused on a thin layer of agarose in order to detect the carriers of the A gamma 75Thr chain (A gamma chain bearing a replacement Ile-->Thr at position 75). Nineteen individuals (10%) were positive for this variant. The frequency of the A gamma 75Thr gene in the Tunisian population (0.050) is compared with that of various ethnic populations.

Fetal Hemoglobin↗
PubMed1981

Hemoglobin Hotel-Dieu beta 99 Asp replaced by Gly (g1). A new abnormal hemoglobin with high oxygen affinity.

Hemoglobin Hotel-Dieu was detected by isoelectric focusing during investigation of a patient who had erythrocytosis. This variant migrates on cellulose acetate electrophoresis to a cathodic position relative to Hb F. In hemoglobin Hotel-Dieu, aspartic acid is substituted by glycine in position 99 of the beta chain. As in other abnormal hemoglobins in which substitution of this residue has occurred, Hb Hotel-Dieu exhibits a high oxygen affinity and is associated with familial erythrocytosis.

Adult↗
PubMed1981

Isoelectric focusing of human hemoglobins.

Isoelectric focusing on thin layer of acrylamide gel has been used for the characterization of 79 different variants of hemoglobin A. This method has replaced the cellulose acetate electrophoresis in clinical laboratories in Martinique, Guadeloupe and Creteil for the detection of abnormal hemoglobins in populations at risk. Up to now 15,000 samples from adults have been evaluated. In addition this method has been used for the screening of 7,000 cord blood samples and for the prenatal diagnosis of severe hemoglobinopathies.

Adult↗