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Biomedical subjects

J Etiemble

Publications and source records attributed to J Etiemble.

29 records · Page 2Linked to original sources
PubMed1980

Gd(-) Rennes, a new deficient variant of glucose-6-phosphate dehydrogenase associated with congenital nonspherocytic hemolytic anemia found in France.

A new variant of G6PD with total enzyme deficiency associated with nonspherocytic hemolytic anemia in a 60 year old Frenchman is characterized. Partially purified enzyme revealed slow electrophoretic mobility, decreased G6P affinity, thermal instability, abnormal pH curve with a single peak at pH 5.0, abnormal utilization of 2-deoxy-G6P and deamino NADP. This variant differs from all previously reported variants associated with chronic nonspherocytic hemolytic anemia. Accordingly this variant is designated Gd(-) Rennes.

Anemia, Hemolytic, Congenital Nonspherocytic↗
PubMed1980

Studies on the mechanism of the erythrocyte enzyme abnormalities induced by chemotherapy.

With the aim of determining the possible mechanisms of the red cell enzyme deficiencies induced by chemotherapy, deficient red cell glucose-6-phosphate dehydrogenase (G-6-PD), pyruvate kinase (PK) and phosphofructokinase (PFK) from 17 patients were purified and characterized. In all cases G-6-PD showed normal kinetics, electrophoretic mobility and thermostability suggesting that a decreased enzyme synthesis was possible for the deficient enzyme activity. In each case studied, at least one of the PK properties was modified, either in affinity for phosphoenol pyruvate, thermal stability or electrophoretic mobility, indicating a primary or secondary molecular abnormality. In some patients PFK had significantly increased affinity for citrate inhibitor; however, neither the quantity nor quality of the M subunits seemed to be altered. Thus it appears that chemotherapy can induce qualitative as well as quantitative red cell enzyme abnormalities by different mechanisms. These are similar to those observed in spontaneous leukaemia and preleukaemic states. Such a similarity poses the question of whether or not the red cell enzyme abnormalities induced by chemotherapy could be considered as the first sign of secondary leukaemia due to treatment by oncostatic drugs.

Antineoplastic Agents↗
PubMed1979

Red blood cell enzyme abnormalities in patients treated with chemotherapy.

Sxiteen red blood cell enzyme activities and fetal haemoglobin level have been assayed in 60 patients treated for haematologic or nonhaematologic malignant diseases with various combinations of cytostatic drugs. Acquired enzyme deficiency was found in 20 patients. The most frequently decreased activities were those of G6PD (12 cases), PK (seven cases), PFK (six cases) and AK (three cases). In many patients decreased activity of some enzymes contrasted with increased activity of others such as ALD, TPI, G3PD, PGK, ENOL and 6PGD. The number of abnormalities seems to be related to the duration of the treatment. Incidence of enzyme deficiencies was similar in patients previously treated or not with radiotherapy. Enzyme abnormalities were correlated neither with haemoglobin level nor with reticulocyte count. They were very similar to those observed in primary acquired dyserythropoietic and preleukaemic states. Their prognostic value and mechanism are discussed.

Drug Therapy, Combination↗
PubMed1979

Phosphofructokinase isozymes from human organs and blood cells.

Phosphofructokinase (PFK) isozymes of blood cells and some human tissues were studied by starch gel electrophoresis and immunoprecipitation by anti-muscle and anti-erythrocyte PFK sera. PFK from muscle, heart, brain and placenta were totally precipitated by both antisera. PFK from blood cells (erythrocytes, lymphocytes, granulocytes, platelets) were precipitated more strongly by anti-erythrocyte PFK serum than by anti-muscle PFK serum. Liver, kidney and monoblast PFK were slightly precipitated by both antisera. From the electrophoretic patterns and the immunoprecipitation curves we may conclude that muscle contains the homotetrameric M4 forms; platelet, liver and kidney the homotetrameric E4 form, and blood cells the M-E hybrids. Monoblasts probably contain a E4 type PFK precursor, and heart, placenta and brain, a modified M4 type PFK. Other isozymes, unrelated with muscle and erythrocyte, were revealed in liver and kidney.

Blood Cells↗
PubMed1977

Complex kinetics of human leukocyte and platelet pyruvate kinases.

In the presence of SH group protectors, human leukocyte and platelet pyruvate kinases demonstrate biphasic kinetics with respect to the phosphoenolpyruvate substrate. SH group oxidation by oxidized glutathione reveals positive cooperativity kinetics for purified preparations of leukocyte and platelet pyruvate kinases. Complete reversal of the phenomenon may be obtained by incubation for several hours in dithiothreitol. This communication illustrates the existing relationships between enzyme conformation, the redox state of the SH groups, and the observed kinetics.

Blood Platelets↗
PubMed1977

Reaction mechanism of erythrocyte phosphofructokinase.

The reaction mechanism of erythrocyte phosphofructokinase (PFK) was investigated by the initial velocity and the product inhibition. Intersecting lines obtained with initial velocity studies are consistent with a sequential mechanism and the formation of ternary complex as an intermediate. The product inhibition studies support an ordered Bi Bi mechanism in which fructose 6 phosphate (F6P) is the first substrate binding and adenosine diphosphate (ADP) is dissociated from the enzyme before fructose-1,6-P2 (FDP).

Adenosine Diphosphate↗
PubMed1976

Hereditary hemolytic anemia with erythrocyte phosphofructokinase deficiency: studies of some properties of erythrocyte and muscle enzyme.

A case of hereditary nonspherocytic hemolytic anemia associated with partial erythrocyte PFK deficiency without muscular symptoms is reported: erythrocyte enzyme activity in the propositus was 60% of normal. Kinetic studies of erythrocyte PFK revealed increased sensitivity to ATP inhibition and decreased sensitivity to citrate inhibition. Muscle PFK from the patient had a normal enzymatic activity, but was highly unstable to heat, dilution without stabilizer and urea; furthermore its starch gel electrophoretic mobility was markedly faster than the one of a normal control. The results suggested that a muscle type's subunit was deficient in the erythrocyte PFK. The authors hypothesize that there was no PFK deficiency in the patient's muscle because of the active synthesis of proteins by this tissue. In contrast, the deficiency of PFK would be easily detected in erythrocytes, because of the absence of protein synthesis.

Adenosine Triphosphate↗
PubMed1976

Pyruvate kinase isozymes among human organs and blood cells.

In extracts of human tissues only three different pyruvate kinases were demonstrated by acetate gel electrophoresis. Treatment with reduced glutathione resulted in an alteration of electrophoretic mobility of extracts from kidney and testis. The existence of interconvertible forms of M2 pyruvate kinase (PK) was suggested. Lymphocytes, polymorphonuclear cells, platelets were M2 type PK. An electrophoretic slow form was demonstrated in myeloblasts and lymphoblasts.

Electrophoresis, Cellulose Acetate↗
PubMed1975

Erythrocyte phosphofructokinase deficiency associated with an unstable variant of muscle phosphofructokinase.

A case of chronic non-spherocytic hemolytic anemia due to partial erythrocyte phosphofructokinase deficiency (61% of normal) is reported. Immunological studies in hemolystates, using anti-muscle and anti-leukocyte phosphofructokinase antisera, seemed to indicate that an isozyme of the muscle type was deficient in the patient. This hypothesis was confirmed by the studies of muscle phosphofructokinase; this enzyme was an unstable and fast variant. There was no deficiency in muscle because of the active synthesis of proteins by this tissue, but the deficiency could be detected in erythrocytes, old cells which are no longer able to synthesize proteins.

Adolescent↗
PubMedDate not supplied

Rearrangement and enhanced expression of c-myc in hepatocellular carcinoma of hepatitis virus infected woodchucks.

Hepatocellularcarcinoma (HCC) that occur in woodchucks chronically infected with woodchuck hepatitis virus (WHV) were screened for activation of cellular oncogenes. Enhanced expression and allelic alterations of the c-myc oncogene were found in three HCC out of nine. Variations in the size of the c-myc transcripts, ranging from 2.0 kilobases (kb) to 5.6 kb, as well as in the level of c-myc gene expression, 5-50-fold higher than in adjacent liver tissues, were observed among the three HCC. Rearrangements of the c-myc locus were either upstream of the gene or within the first intron. Cloning and sequencing of the break-point region from one of the three tumours showed that the c-myc gene was truncated and joined to a unique cellular sequence of unknown function. WHV DNA was not integrated near the c-myc coding exons, excluding a direct role of the virus in c-myc activation. The novel type of rearrangement and activation of the c-myc gene, reported here in liver tumours of hepatitis virus infected animals, appears strikingly similar to those resulting from chromosomal translocations in human Burkitt's lymphomas, acute B- and T-cell leukaemias and mouse plasmacytomas.

Alleles↗