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A Zanella

Publications and source records attributed to A Zanella.

At least 109 records · Page 6Linked to original sources
PubMed1979

Significance of the electrophoretic modifications of defective pyruvate kinase variants. Study of six new observations.

Six new defective pyruvate kinase variants have been characterized in patients suffering from chronic hemolysis. Partially purified enzyme variants exhibited various anomalies from immunological, kinetic, stability and electrophoretic points of view. The significance of the electrophoretic anomalies has been interpreted in view of the normal post-synthetic maturation of the precursor enzyme L'4 into L2L'2 and L4, and the ability of trypsin to induce in vitro the transition L'4 leads to L4 has been tested. One defective enzyme existed in a single L'4 form and could not be transformed by trypsin into L4. In three cases slow-moving L'4 and L2L'2 forms were transformed by trypsin into an abnormal slow-moving L4 form. In the last two observations the L'4 and L2L'2 forms exhibited normal mobility and were normally transformed by trypsin into L4. The relevance of these data to the functional anomalies of the defective variants and to the nature of the primary genetic anomaly giving rise to the congenital defects in erythrocyte pyruvate kinase is discussed.

Anemia, Hemolytic, Congenital↗
PubMed1979

Membrane abnormalities of pyruvate kinase deficient red cells.

Two experimental systems have been applied to the study of PK-deficient red cells in an attempt to reveal possible membrane abnormalities of these erythrocytes: (1) the glycoprotein self-digestion of intact erythrocytes during in vitro incubation at 37 degrees C; (2) the red cell sensitivity to the lytic action of mouse macrophages. PK-deficient erythrocytes display a more precocious than normal membrane glycoprotein self-digestion and are much more susceptible than normal to the cytotoxic activity of mouse macrophages. This latter effect is more pronounced in young than in old PK-deficient red cells. These observations indicate the existence of membrane abnormality in PK-deficient red cells other than those so far suspected.

Adenosine Triphosphate↗
PubMed1979

Erythrocyte spectrofluorometric abnormalities in Duchenne patients and carriers. A new approach to carrier detection.

Duchenne muscular dystrophy (DMD) is a disorder whose pathogenesis is attributed, according to the most recent theories, to generalized membrane abnormalities, including red cell membrane. The study of erythrocyte ghosts in patients affected by DMD showed alterations in ion transport and in various enzymatic activities. Employing a spectrofluorometric method using 1-anilino-8-naphthalene sufonate (1.8-ANS) we have tried to characterize the erythrocyte ghosts of DMD patients, definite DMD carriers and normal controls, matched for age and sex. We found an increase of membrane polarity in DMD and definite DMD-carrier erythrocyte ghosts. Using this new method we were able to: - confirm by means of a different technique the previous observations of many authors on erythrocyte ghost alterations in DMD - find a new technique useful in detecting the DMD carriers. It is noteworthy that in such a way the detection rate of definite DMD carriers was higher than with the CPK test.

Adult↗
PubMed1979

Concomitance of an active and an inactive mutant of red cell pyruvate kinase (PK).

A new mutant red cell PK associated with mild chronic haemolytic anaemia is described. The propositus, double heterozygous for a maternal gene coding for a structural abnormal enzyme and a paternal gene coding for a catalitically inactive enzyme, was suitable for an accurate functional characterization of the PK variant since his erythrocytes contained only one active mutant form of this enzyme. The active isoenzyme was characterized by low activity, decreased affinity for phosphoenolpyruvate, incomplete fructose-1,6-diphosphate activation, increased 'zero-time transition temperature', increased stability to guanidine-HCl and storage at +4 degrees C, increased guanosine-5'-diphosphate and cytidine-5'-diphosphate utilization, altered electrophoretic pattern with a single slow-moving component and abnormal isoelectric point. Affinity for ADP, ATP inhibition, optimum pH, molecular weight of the subunits, antigen concentration and immunological properties were in the normal range.

Adult↗
PubMed1978

A new mutant erythrocyte glucosephosphate isomerase (GPI) associated with GSH abnormality.

A case of congenital nonspherocytic haemolytic anaemia associated with a new abnormal glucosephosphate isomerase (GPI), GSH (reduced glutathione) deficiency, and instability and altered carbohydrate membrane composition is reported. The only functional abnormality of the mutant enzyme seems to be a marked instability to heat, urea, and guanidine-HCl. Family studies suggest that the propositus is doubly heterozygous for a maternal gene producing an inactive enzyme and a paternal gene responsible for a structural alteration causing marked lability of the coded enzyme. Experiments of incubation of normal GPI and the propositus's GPI with oxidizing and reducing agents seem to indicate that the abnormality resides in the SH groups of the mutant GPI.

Adolescent↗
PubMed1978

Hereditary pyruvate kinase deficiency: role of the abnormal enzyme in red cell pathophysiology.

Two new mutant Pks, electrophoretically identical but kinetically slightly different, are reported. These two clinically innocuous PK variants, encountered in two non-related subjects, have combined in their daughter to give a fully expressed haemolytic anaemia. The functional abnormalities of the daughter's PK (increased K0.5 PEP, abnormal response to FDP, increased urea and guanidine-HCl stability, abnormal isoelectrofocusing and electrophoretic patterns) were like those of the parents but more pronounced, except for thermostability that was normal in the proband although markedly decreased in both parents. The family examined demonstrates that there is no relationship between in vitro properties of the variant and the severity of haemolysis. The hypothesis is put forward that the cause of haemolysis in PK deficiency may be associated with another defect located in the red cell membrane.

Anemia, Hemolytic↗
PubMed1978

[Behavior of mast cells in experimental burns in rats].

The Authors, using a personal dyeing method, specific for mast cells, that they described in a former work, (a modification of May-Gruenwald-Giemsa dye) observed crowd of mast cells in the subcutaneous tissue, below the site of thermal skin burns, in rats. They clearly demonstrate the phenomenon of mast cells degranulation. The granules are released in the subcutaneous tissue, then they go away along the limph vessels, and it is possible to follow them until the limph nodes. There is also crowd of limphocytes and plasma cells; nevertheless, there is evidence that mast cells are the early cells which react to burns in rats. Perhaps it should be possible that mast cells have some immunological function, owing to the contact their granules take with lymphocytes and plasma cells.

Animals↗
PubMed1976

Effects of sulphydryl compounds on abnormal red cell pyruvate kinase.

The effect of some sulphydryl compounds on two new variants of red cell pyruvate kinase (ATP: pyruvate phosphotransferase, PK) is reported. In vitro a striking correction has been obtained of both the qualitative and, in one case, the quantitative defect of red cell PK. In vivo, a correction of the qualitative and quantitative abnormalities has been produced in both patients, with clinical improvement of one of them. These findings, together with the unexpected results in respect to the functional properties of PK found in the affected members of the two families studied, suggest that the PK abnormality is not the cause of the haemolytic anaemia, but an epiphenomenon of a primary unknown defect that apparently involves the red cell thiol groups.

Adenosine Triphosphate↗