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Biomedical subjects

C L Balduini

Publications and source records attributed to C L Balduini.

At least 73 records · Page 4Linked to original sources
PubMed1981

Reversible and irreversible structural modifications of erythrocyte membrane.

Membrane glycoprotein structure regulates the fate in the circulation of mammalian erythrocytes: the mechanism of this phenomenon was observed in rabbit and human red cells by in vivo and in vitro experiments. Glycoprotein remodeling can occur as a reversible desialylation process, produced by different events, or as an irreversible process consisting in a loss of sialoglycopeptides. The effect of these two phenomena on the viability of the red cell in the circulation was the subject of our investigation.

Amino Acids↗
PubMed1978

Behaviour of young and old desialylated rabbit erythrocytes in vivo.

Young and old rabbit erythrocytes, separated by density gradient centrifugation, were desialylated by neuraminidase treatment and reinjected into the animal after 51Cr labelling. Both red cell populations are quickly removed from the circulation and trapped by the liver; then a large percentage of the young cells reappear in the peripheral blood and behaves like untreated erythrocytes; old cells, on the contrary, do not return to the blood stream and are probably lysed in the liver. These results suggest that a sialic acid repair can occur on the membrane of young erythrocytes and confirm that the loss of this molecule is not by itself sufficient to determine the death of the cell.

Animals↗
PubMed1977

In vivo behaviour of neuraminidase-treated rabbit erythrocytes and reticulocytes.

51Cr rabbit erythrocytes were treated with different amount of neuraminidase and reinjected into the animal. The survival curves after the removal of more than 50% membrane sialic acid show a characteristic behaviour: after a rapid decrease, blood radioactivity increases again reaching a maximum level 50-80 h after reinjection, then tends to decrease with a slope similar to that of control curves. Liver radioactivity determined before the rise of blood radioactivity is evidently higher than the value determined after radioactivity elevation. Similar results were obtained with phenylhydrazine-induced young erythrocytes.

Animals↗
PubMed1977

Membrane sialic acid and behaviour in vivo of rabbit "stress" macroreticulocytes.

Membranes of rabbit reticulocytes obtained by phenylhydrazine stimulation have a chemical composition different from that of normal erythrocytes; sialic acid/protein and cholesterol/protein ratios are in fact lower than normal. In vivo study of 51Cr-labelled reticulocytes show that these cells are quickly removed from blood and, after a short "homing" in liver, return to peripheral blood. During "homing" in the liver, the sialic acid/protein ratio seems to increase.

Animals↗
PubMed1976

Identification of a sialoglycopeptide released by self-digestion from human erythrocyte membranes.

Membranes from human O Rhesus-positive erythrocyte 'ghosts' were tested in vitro for their ability to digest their own glycoproteins. 'Ghost' membranes incubated in Tris/HCl buffer, pH 7.4, release a sialoglycopeptide, which contains glucosamine, galactosamine, galactose and mainly polar amino acids. Chemical composition, molecular size and aggregation properties suggest that this glycopeptide may be a fragment of glycophorin.

Chromatography, Gel↗
PubMed1976

Glycopeptides of erythrocyte membranes in some hematological disorders.

Red cell membrane glycopeptides of subjects suffering from different hematological disorders (PNH, hemolytic anemias, dyserythropoietic anemias and polycythemia vera) have been characterized. In most cases, except in polycythemia vera, a decrease of sialic acid and galactosamine was detected. The role of these alterations is discussed with regard to the decrease of membrane glycopeptides during physiological aging of the red cell.

Adult↗
PubMed1974

Membrane glycopeptides from old and young human erythrocytes.

Glycopeptides were extracted by papain digestion from old and young human erythrocyte membranes and fractionated on DEAE-Sephadex A-25. Chemical characterization of the unfractionated samples and of the main peak eluted from the column indicates that glycoproteins of the erythrocyte membrane undergo significant decreases in sialic acid and galactosamine content with aging.

Cell Membrane↗
PubMedDate not supplied

Structural modifications in membrane glycoproteins during the erythrocyte life-span.

Erythrocyte membrane glycoproteins undergo various types of modification during the life of the cell in the circulation; when only sialic acid is removed, the younger red cells can be repaired in the liver and return to the circulation. Otherwise, when an autolytic mechanism removing a sialopeptide becomes active as a consequence of the metabolic impairment of the cell, the erythrocyte is probably trapped by the hemocatheretic organs and destroyed.

Adenosine Triphosphate↗
PubMedDate not supplied

Heparin infusion facilitates ex vivo spontaneous platelet aggregation in patients with acute myocardial infarction who have undergone thrombolytic therapy.

We investigated ex vivo spontaneous platelet aggregation (SPA) in platelet-rich plasma in 37 patients with acute myocardial infarction. It occurred in about 50% of subjects receiving heparin after streptokinase treatment, while it rarely took place in patients who did not receive either streptokinase or heparin and in those treated with streptokinase alone. The study of patients receiving heparin for deep vein thrombosis suggested that SPA may derived from adenosine diphosphate released from platelets during sample handling. We suggest that heparin infusion may facilitate ex vivo platelet activation and that this mechanism is operative in patients with acute myocardial infarction who have undergone thrombolytic therapy.

Heparin↗