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Biomedical subjects

F Piovella

Publications and source records attributed to F Piovella.

At least 55 records · Page 3Linked to original sources
PubMed1986

Migratory capacity of large granular lymphocytes from T-gamma-lymphoproliferative disorders.

We have investigated 10 patients with T gamma-lymphoproliferative disorders (T gamma LPD) for cell migratory capacity. Large granular lymphocytes (LGLs) expanding in these subjects expressed natural killer cell markers (HNKI, B73.1, AB8.28, N901, OKM1) to a variable extent. The patients' LGLs mediated antibody-dependent cellular cytotoxicity, while appreciable natural killer activity was only measurable in 3 patients. The migratory capacity of T gamma LPD was examined by using nitrocellulose filters. The patients' LGLs migrated into filters and showed responsiveness (in 9 of 10 patients) to activated serum, used as chemoattractant, as normal LGLs do. No clearcut correlation emerged between in vitro migratory capacity and disease aggressiveness or involvement of abdominal organs. These results confirm in T gamma LPD the migratory potential of LGLs and suggest the possibility that acquisition of enhanced locomotor capacity is not a crucial determinant of disease aggressiveness in T gamma LPD.

Adult↗
PubMed1984

Extracellular matrices produced in the presence of dexamethasone: a natural "growth agent" for human cultured endothelium.

Cultured endothelium synthesizes an extracellular matrix that resembles the basement membrane of the vessels. We studied the aspect of extracellular matrices produced in presence or absence of dexamethasone by immunofluorescent technique for fibronectin; the glycoprotein is more abundant in matrices produced in the presence of dexamethasone than controls and forms a very dense meshwork. When endothelial cells resuspended in medium without FCS were seeded on these preformed matrices they adhered and replicated. The endothelium grown on matrices preformed in the presence of steroid showed a better morphology and covered a greater area indicating the presence of more abundant fibronectin content in basal lamina.

Cell Adhesion↗
PubMed1984

The effect of ticlopidine on human endothelial cells in culture.

The effect of ticlopidine at various concentrations (150, 30, 6 microM), has been studied on cultured endothelial cells derived from human umbilical cord vein. Ticlopidine affects the initial attachment of endothelial cells to artificial substrata and has an inhibitory effect on endothelial cell growth rate which correlates to the concentration of the chemical in the culture medium. These effects are related to a marked reduction of intra- and extracellular fibronectin as evidentiated by immunofluorescence. The drug seems to interfere with the formation of fibronectin filaments from intracellular granules. The reduction of fibronectin availability could affect platelet adhesion to subendothelium as well as endothelial cell repair, and subsequently influence the bleeding time. The inhibition of cell proliferation and its possible effect on the thickness of the vessel wall should be considered as additional mechanisms of action for this substance.

Anticoagulants↗
PubMed1983

Interactions between tumor cells and vascular endothelium.-I) Adhesion properties of cell lines with different metastasizing capacity.

The authors describe the adhesive properties of four murine tumor lines, chemically and virus induced, with different metastasizing potential. Cancer cells show similar behaviour in attachment kinetics when tested with endothelium monolayer or plastic surfaces, without differences between the lines with high or low malignancy. The time required for a complete adhesion to endothelial cells is three hours while to plastic surfaces is 90 min. The role of divalent cations is not required in the first phases of cellular attachment of tumor lines to plastic dishes.

Animals↗
PubMed1983

Interactions between tumor cells and vascular endothelium.-II) Light and electron microscopic studies.

Electron microscope technique was used to investigate the passage across the endothelial monolayer by murine tumor lines. After the initial adhesion, cancer cells induce a retraction of endothelium and migrate under vascular intima. Subsequently they spread on basement membrane showing a flattened shape, meanwhile endothelial cells reconstitute the monolayer. The four tumor lines show a similar behaviour being able to induce endothelial retraction and exposure of extracellular matrix and cross through the monolayer. The technique appears useful to study in details this multi-step process.

Animals↗
PubMed1982

Immunohistological comparison of platelet factor 4 (PF4), fibronectin (Fn) and factor VIII related antigen (VIIIR:Ag) in human platelet granules.

Immunofluorescence microscopy was used to study the localization of platelet factor 4 (PF4), fibronectin (Fn) and factor VIII related antigen in washed normal platelets and those from patients with severe von Willebrand's disease (vWd). Platelets were prepared by an improved multi-unit modification of the Sayk chamber. This facilitated the preparation of samples with minimum disruption of platelets and readily permitted the demonstration of intact platelet granules by the immunological techniques used. The antigens were demonstrated by treating the same preparations sequentially with appropriate heterologous antisera and species specific fluorescein or rhodamine conjugated antisera. Comparison of the different antigens in identical platelets indicated that Fn and VIIIR:Ag were localized to the same granules as PF4 and the results were thus consistent with their presence in alpha granules. Fn and PF4, but not VIIIR:Ag, were present in platelet granules of patients with severe vWd. The antigens were always detected in the same granules, and major sub-populations of differently stained granules were not observed. The methods were applied to investigate normal platelets aggregated with collagen. Fn and VIIIR:Ag were detected in platelet granules after aggregation although the granules themselves were possibly differently distributed in these samples compared with the non-aggregated platelets. The localization of PF4 could not be reliably assessed in aggregated platelets by these methods. The techniques may be useful in localizing platelet antigens and studying release during aggregation.

Antigens↗
PubMed1980

Characterization of procoagulant activity produced by cultures of human monocytes and lymphocytes separated in colloidal silica-polvinylpyrrolidone gradients.

Human peripheral blood leucocytes were examined for their ability to synthesize procoagulant activity in tissue culture. A method was developed utilizing silica coated with polyvinylpyrrolidone (Percoll) to separate monocytes from lymphocytes prior to culture. Coagulation activity was demonstrated in all mononuclear cell cultures after 24 hours incubation. This activity was inhibited by phospholipase C which suggested that tissue thromboplastin was the major source of activity. Specific immunoradiometric assays failed to demonstrate synthesis of factor VIII related antigen (FVIIIRAG) or factor VIII coagulant antigen. The results indicate that under conditions of this study factor VIII was not synthesized in mononuclear cell cultures.

Cell Separation↗
PubMed1978

[B-lymphocytes in multiple sclerosis: studies concerning their levels in the blood and cerebrospinal fluid].

In this paper the B lymphocyte population was investigated by fluoresceinated immunoglobulin assay in peripheral blood and cerebrospinal fluid (CSF) in M.S. patients and other neurological diseases taken as control. In peripheral blood there was no significant difference in two groups considered. In CSF there was a higher percentage of B-cells only in M.S. patients. This datum was more evident when the percentage of B cells was simultaneously determined in CSF and blood. It can be hypothesized the existence of subpopulations of B cells synthesizing Ig in the CST.

Adult↗
PubMed1978

The ultrastructural localization of factor VIII-antigen in human platelets, megakaryocytes and endothelial cells utilizing a ferritin-labelled antibody.

By means of electron microscopy combined with the use of monospecific anti-factor VIII-antigen (VIIIR:AG) antibodies conjugated to ferritin, the subcellular localization of VIIR:AG in platelets, megakaryocytes and in endothelial cells has been established. The reported results suggest the possibility that the megakaryocyte is able to synthesize VIIIR:AG and also to secrete it by means of a microcanalicular system similar to that present in the endothelial cell. Platelets may derive their VIIIR:AG content partly from the megakaryocyte and partly from the plasma.

Antigens↗