Biomedical subjects

C Galand

Publications and source records attributed to C Galand.

At least 73 records · Page 4Linked to original sources

PubMed1977

A Spanish family with erythrocyte pyruvate kinase deficiency: contribution of various immunologic methods in the study of the mutant enzyme.

Erythrocyte PK deficiency was detected in a 38-year-old man from Catalonia, in Spain. His father and his three children were proven to be heterozygous for the same mutant PK variant. This variant was characterized by low immunologic specific activity, normal (or slightly increased) stability to heat and to urea; normal isoelectric point, increased K0.5 for phosphoenolpyruvate, increased inhibition by ATP and normal activation by 0.35 mM fructose 1,6-diphosphate. The mutant PK variant was antigenically identical with wild enzyme as tested against anti wild erythrocyte PK serum by double immunodiffusion and micro complement fixation. The utility and the significance of the immunologic methods to be used in the study of mutant PK variants are discussed.

Adult↗

PubMed1977

Erythrocyte membrane phosphorylation in hereditary spherocytosis.

Phosphorylation of erythrocyte membrane proteins by membrane protein kinases was studied in 10 normal subjects and 8 patients with hereditary spherocytosis. No difference between the two groups of subjects was observed in the total phosphorylation, and, the phosphorylation of spectrin and components III and IV 5 in presence and in absence of 3',5'-cyclic AMP. So, no deficiency of membrane protein kinase activity seems to be present in hereditary spherocytosis.

Adult↗

PubMed1977

A deficient pyruvate kinase with an electrophoretically slow-moving component.

A deficient erythrocyte pyruvate kinase observed in a patient with congenital non-spherocytic anaemia was characterized by the following properties: very low activity in haemolysates, decreased thermal stability, slightly increased urea denaturation, high affinity for PEP, poor FDP activation, normal ATP inhibition, decreased affinity for ADP, normal pH of optimal activity, and presence of an abnormal slow-moving component in this layer polyacrylamide gel electrophoresis. The patient was probably double heterozygous for two different deficient mutants of erythrocyte pyruvate kinase.

Adenosine Diphosphate↗

PubMed1977

[Erythrocyte membrane protein abnormalities in hereditary hemolytic anemias].

The structural and functional abnormalities of erythrocyte membrane proteins in hereditary hemolytic anemias are reviewed. The authors stress the problems of protein solubilization and the artefacts of the sodium dodecylsulphate polyacrylamide gel electrophoresis; protein abnormalities observed with that method are inconstant and non-specific. Abnormal "spectrin" has been reported in hereditary spherocytosis: however analysis of purified spectrin peptides by isoelectric focusing in 8M urea did not reveal any difference between normal and hereditary spherocytosis spectrin. Deficient autophosphorylation of erythrocyte membrane proteins by endogenous membrane protein-kinases 3'5-cyclic-AMP dependent and independent was pointed out in hereditary spherocytosis and stomatocytosis: the authors' experience was contrary to such results: quantitatively and qualitatively normal activity of membrane protein-kinase was found in five cases of hereditary spherocytosis. The authenticity, frequency and specificity of the various membrane protein abnormalities reported so far, are not firmly established. Many insufficiently verified results published prematurely have been later denied. To date no membrane protein anomaly may be considered as a biochemical cause of any type of hereditary hemolytic anemia.

Anemia, Hemolytic, Congenital↗

PubMed1977

Phosphorylation of human erythrocyte membrane protein. Differences according to the assay procedure.

Phosphorylation of the human erythrocyte membrane proteins by gamma (32P) ATP was studied at pH 6 and pH 7.4, at 30 degrees C, with incubation times varying from 5 to 90 minutes, and with or without cyclic AMP. Incorporated radioactivity was much higher at pH 7.4 because of the prevalent activity of cAMP independent protein-kinase. Maximum incorporation was obtained in both pH after 30-45 minutes incubation, thereafter incorporated radioactivity was either stable or decreased. The part of the radioactivity due to cAMP stimulation was low and seems constant with the incubation time. Analysis of the substrates showed the predominant cAMP independent protein kinase activity in the phosphorylation of the spectrin second component and component III and that of cAMP dependent activity in the phosphorylation of component II4, IV5 and other minor bands.

Adenosine Triphosphate↗

PubMed1977

[Significance of kinetic abnormalities of erythrocyte pyruvate kinase in congenital deficiencies].

Kinetic studies of semi-purified pyruvate kinase were performed from the erythrocytes of 22 subjects with congenital non-spherocytic anemia with pyruvate kinase deficiency and 25 heterozygous relatives. The study of enzyme affinity for PEP with and without ligands fructose-diphosphate (FDP) and ATP allowed to separate three groups of patients: --in eight patients and their eleven heterozygous relatives, the PK kinetic characteristics were similar to those of controls. Allosteric properties of the enzyme were normal; --in three patients, PK was in an activated form, non sensitive to FDP activation and to ATP inhibition in the experimental conditions. The deficient enzyme seemed to be present in the "R" form; --in eleven patients affinity for PEP was decreased; the enzyme was in each case activated by FDP; however very high FDP concentrations did not allow to obtain a complete activation and an n Hill of 1. ATP inhibition was more important than in controls. Similar results were obtained in some heterozygous relatives. The pyruvate kineases of these patients seemed to be fixed in "T" form. Whatever may be the molecular abnormalities responsible for the PK deficiency, they seem to lead in many cases to a change in the enzyme allosteric properties.

Adenosine Triphosphate↗

PubMed1976

Isoelectric focusing of spectrin components in hereditary spherocytosis.

1. By isoelectric focusing in 8 M urea, spectrin purified from normal human erythrocytes was resolved into 12 to 15 peptide bands differing by their isoelectric point. Most of them were focused between pH 6.4 and 5.2, one at pH 8.7 and some minor components between pH 7.4 and 6.8. 2. The results were not influenced by the erythrocyte population age. 3. Spectrin purified from erythrocytes of five patients with hereditary spherocytosis gave similar isoelectric focusing patterns, with the exception of the lack of the pH 8.7-focused component in two related patients.

Erythrocyte Aging↗

PubMed1976

Human erythrocyte phosphoglycerate kinase deficiency: presence in a deficient patient of a stable variant with lowered catalytic activity.

The phosphoglycerate kinase deficiency found in one boy with hemolytic anemia was associated with an almost normal concentration of phosphoglycerate kinase-immunologically related material in the patient's erythrocytes. Consequently the catalytic activity of the mutant enzyme was drastically lowered. Besides, the abnormal phosphoglycerate kinase was more stable to heat and to urea than normal phosphoglycerate kinase and its isoelectric point was slightly increased.

Adult↗

PubMed1976

Chronic haemolytic anaemia in two patients heterozygous for erythrocyte pyruvate kinase deficiency. Electrofocusing and immunological studies of erythrocyte and liver pyruvate kinase.

Two patients with mild chronic haemolytic anaemia, a mother and her son, were found to be heterozygous for erythrocyte pyruvate kinase deficiency. In the red blood cells the enzymatic activity was reduced by about 50% and the residual PK had normal kinetic properties, stability and electrofocusing pattern. The PK antigen concentration was also decreased by half, so that the ratio of the enzymatic activity to the immunological reactivity (i.e. the molecular specific activity) was normal. In the son's liver PK enzymatic activity was slightly reduced and, above all, an abnormal active form, more anodic than normal PK, was detected by electrofocusing. The propositus's liver PK was also slightly thermo-unstable. It is suggested that the patients were heterozygous for an unstable PK variant which is found in liver, nucleated tissue actively synthesizing proteins, but which disappeared from the erythrocytes because of its unstability.

Adult↗

PubMed1976

Causal mechanisms of multiple acquired red cell enzyme defects in a patient with acquired dyserythropoiesis.

A patient with an unclassified form of acquired dyserythropoiesis was found to have multiple defects in erythrocyte enzyme activity, involving especially pyruvate kinase (PK), glucose phosphate isomerase (GPI), and phosphofructokinase (PFK). The PK activity defect was associated with a normal concentration of PK-related antigen, and the enzyme could be reactivated during the procedure of partial purification of the enzyme. The concentration of GPI-related antigen was as reduced as the GPI enzymatic activity, and the defect was not improved by any treatment (cross-incubation of red cells or treatment of the hemolysate by SH reagents); the residual enzyme had a normal stability to heat, and a normal electrophoretic and electrofocusing pattern. The PFK activity defect was not improved either by cross-incubation of red cells or by treatment with SH reagents. Immunologic data with antimuscle and antileukocyte antisera seemed to indicate that the defect involved especially the muscle-type subunit of erythrocyte PFK. In agreement with this assumption was the fact that deficient PFK was markedly more inhibited by ATP than normal enzyme. Changes similar to those of deficient PFK herein studied were noted for PFK of unfractionated erythrocytes from premature newborns or of "old" erythrocytes from full-term infants. It appeared that each of the three enzyme defects detected in the patient could be due to a different mechanism, involving post-translational changes, decreased synthesis, and possible reversion of the genetic regulation mechanisms of the abnormal erythroid precursors toward a fetal type. The possible relationships between these various phenomena and the nature of a hypothetical common underlying cause are discussed.

Anemia, Hemolytic, Congenital Nonspherocytic↗

PubMed1975

Molecular mechanism of erythrocyte pyruvate kinase deficiency.

Erythrocyte pyruvate kinase (PK) from 5 patients with cogenital non-spherocytic hemolytic and erythrocyte PK deficiency have been studied by immunological methods and electrofucusing. L type immunologically related PK was titrated in crude hemolysate with anti human liver L type PK rabbit serum and M2 type immunologically related PK with anti human leukocyte M2 type PK serum. After partial purification, molecular specific activity of erythrocyte PK was measured by immunoinactivation and electroimmunodiffusion and anti L type PK serum. Partially purified erythrocyte PK was focused on continuous sucrose gradient with 2% ampholines covering the pH range 5--8. PK enzymatic deficiency was due two times to a lowered molecular specific activity of the PK variants, the concentration of PK antigen being in the normal range. In the 3 other cases enzyme activity and immunological reactivity were likewise lowered. In the 2 patients with the most marked erythrocyte PK deficiency about 50% of the residual activity in crude hemolysate were non inhibited by anti L type PK serum, but were inhibited by anti M2 type PK serum. In 3 patients, the electrofocusing pattern of partially purified PK was significantly different from than of normal controls. In conclusion, the heterogeneity of the molecular mechanisms of the deficiency on the one hand, and the abnormalities of electrofucusing patterns on the other hand, seem to indicate that erythrocyte PK deficiency is due to the synthesis by muted structural genes of various abnormal PK molecules.

Anemia, Hemolytic, Congenital Nonspherocytic↗

PubMed1975

[March hemoglobinuria. One case with erythrocyte glutathione peroxidase deficiency].

A new case of march haemoglobinuria seen in a 21-year-old man is reported. A deficiency in two erythrocytic enzymes (glutathione reductase and glutathione peroxydase) was observed. Treatment with riboflavin corrected the glutathione reductase deficiency. The march haemoglobinuria and glutathione peroxydase deficiency persisted. Several months after resolution of the march haemoglobinuria, a new estimation of glutathione peroxydase showed that the deficiency had disappeared. The possible role of a transient deficiency in erythrocyte glutathione peroxydase in the pathogenesis of march haemoglobinuria is discussed.

Adult↗

PubMed1975

Acquired erythroenzymopathies in blood disorders: study of 200 cases.

Enzyme abnormalities are frequently found in the red cells of patients with various acquired blood disorders. In leukaemias, preleukaemic states and bone marrow insufficiencies with or without sideroblastosis, changes in enzyme activity are usually characterized by the coexistence of deficiency of some enzymes and an increased activity of others. The most frequently decreased activities are those of pyruvate kinase, phosphofructokinase,2,3-diphosphoglycerate mutase and adenylate kinase; the most frequently increased activities are those of hexokinase, aldolase, enolase, 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase. In primary myelofibrosis and in polycythaemia rubra vera, enzyme deficiencies are infrequent and differ from those observed in leukaemias and related disorders. Phosphohexose isomerase and phosphoglucomutase deficiencies seem relatively specific for polycythaemia rubra vera. Explanations for the acquired enzymopathies are still at the stage of hypothesis. The theory of multiple genetic damage may explain some findings but has not yet been proved right. The possibility of post-translational molecular modification is suggested as a working hypothesis.

Anemia, Aplastic↗

PubMed1975

Acquired red cell pyruvate kinase deficiency in leukemias and related disorders.

The authors studied red blood cell pyruvate kinase activity of 202 patients with various hemopathies. A PK deficiency of moderate grade was found in 39% of patients with acute myeloblastic leukemias, in 57% of those with primary medullary insufficiency without aplasia, in 61% of those with refractory sideroblastic anemia. The PK deficiency was often associated with deficiencies of other red cell enzymes. The mechanism of such enzyme abnormalities was discussed with the hypothesis of a post-translational molecular alteration.

Anemia↗

PubMed1974