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Biomedical subjects

G Zavagli

Publications and source records attributed to G Zavagli.

At least 37 records · Page 2Linked to original sources
PubMed1983

Sickling and Vinblastine.

After incubation of sickle anaemia (SS) erythrocytes for 1 hour at room temperature with Vinblastine (VBL) doses (0.2 mM) far lower than those capable of causing spherostomatocytosis of normal red blood cells (0.6 mM), the percent of erythrocytes which underwent swelling resulted to be overlapping the percentage of cells which showed irreversible sickling (IS) after adequate deoxygenation. Thus VBL can reveal in the SS erythrocytes the most liable cohort of cells that show IS; this may be accounted for by the fact that in both irreversibly sickled and VBL-incubated erythrocytes there are overlapping disorders of the membrane cationic traffic. The increase of the drug concentrations induced an exponentially related cohort of SS erythrocytes to swell. The observed failure of SS erythrocytes previously incubated with VBL to sickle after adequate deoxygenation is accounted for by the close interaction of the drug with the red cell membrane subunits, which renders the red cell surface unliable to undergo further morphological alterations.

Adolescent↗
PubMed1982

[Drugs and renin].

Explore the source record for details and available documents.

Adrenergic alpha-Agonists↗
PubMed1982

Why inclusion bodies do assume different locations in thalassaemic erythrocytes.

The reported scanning (SEM), transmission (TS), and freeze-etching (FE) electron microscopic studies have agreed in confirming that in thalassaemic erythrocytes, previously incubated with brilliant cresyl blue (BCB), the unpaired alpha chains precipitate in the central portions of the cell whereas excess beta chains locate in the submembranous regions. This is due to the fact that beta chains, possessing two thiols instead of only one (as in alpha chains), are more liable to bind to similar groups contained in the inner red cell leaflet. Less soluble alpha chains tend to form inter-chain bridges and thus precipitate centrally. SEM observations have given evidence that on the surface of the affected red cells denaturated alpha chains give rise to large and shallow invaginations whereas denatured beta chains lead to diffuse wrinkled appearance. The causes of the different SEM aspects have been suggested.

Adolescent↗
PubMed1980

Erythrocytes and "vinca rosea" alkaloids. An in vitro study.

The reported stereoscan images have proved that overtherapeutic amounts of vincristine induce in normal red cells the same effects as vinblastine, i.e. the onset of spherocytosis (in about 30% of the cells) and spherostomatocytosis (in the remainder) associated with distinct smaller vacuoles surrounding the larger cavity. The lowest deformation-inducing doses have been found to be twice as high for vincristine as for vinblastine (0.6mM); this is probably due to the greater interaction of the latter drug (because of its methyl group) with the bilayer phospholipids. Unlike previous reports, the present findings have revealed that the onset of red cell deformation is energy independent, since the same aspects have been recorded in both young and old erythrocytes. Therefore, such deformations must be considered the morphological consequence of a drug-induced mechanical derangement of the membrane subunits. In drug-incubated normal erythrocytes it was found that (a) neither drug exerts any influence on the intraglobular energy production and/or utilization, (b) osmotic fragility is enhanced, and (c) potassium leak is increased. These findings may be considered convincingly consistent with the assumption of a drug-induced mechanical derangement of the bilayer components.

Adolescent↗
PubMed1978

Survival and significance of PNH erythrocytes: a scanning study.

The SEM study of PNH erthrocytes which survived incubations with decreasing dilutions (from 1:640 to 1:20) of fresh compatible serum in isotonic sucrose has indirectly evidenced that spherocytes and spherostomatocytes are the most sensitive population to the complement lytic action; swelling is an osmotic consequence of their membrane hypersusceptibility. In such functional abnormality the swollen red cells are closely followed by the cribrous and pitted erythrocytes. A relationship has been found between percentage of the swollen cells and frequency of PNH haemolytic bouts: these are most likely to occur when spherocytes and spherostomatocytes are above 40% of cells. On the contrary, SEM evaluation of swollen erthrocytes does not allow to express any longer-term prognosis about the severity and the course of PNH, owing to the constantly variable marrow production of abnormal erythrocytes.

Adult↗
PubMed1977

Tolbutamide-induced hemolytic anemia.

A 67-year-old female diabetic is presented who developed a Coombs'-positive hemolytic anemia after a year of treatment with tolbutamide. An IgG antibody was identified in the patient's serum that caused the agglutination of both the patient's red blood cells and tolbutamide-coated erythrocytes in the absence of complement. Such a reaction did not occur with the patient's erythrocytes when not exposed to tolbutamide. Agglutination of the patient's serum also occurred with erythrocytes treated with other sulfonylureas (chlorpropamide, glibenclamide, carbutamide) but not with phenacetin.

Aged↗