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Biomedical subjects

M Vitale

Publications and source records attributed to M Vitale.

At least 181 records · Page 10Linked to original sources
PubMed1990

[Possible correlations between histopathologic morphology and prognosis in gastric carcinoma].

Possible correlations between histological aspects and prognosis of gastric cancer are discussed. The influence of classical histological morphology and the classifications of Lauren and Ming are re-examined in the light of international literature and it is concluded that the histological study of the tumours based on the type of biological growth would seem to offer better prognostic indications.

Humans↗
PubMed1989

Natural killer function in flow cytometry. II. Evaluation of NK lytic activity by means of target cell morphological changes detected by right angle light scatter.

Morphological changes that occur in K562 cells after natural killing produce profound changes in cellular light scattering properties. The possibility of gating out all the effector cells by thresholding on perpendicular light scatter and the subsequent identification of two distinct clusters of cells, which correspond to dead and viable targets, have permitted the measurement of natural killer activity in vitro. The changes in scattering properties after cell death are mainly determined by the variation of internal refractive index of the dying cell. A comparison of the scattering and propidium iodide staining procedures showed good correlation. The morphological detection and measurement of cellular death is therefore used to estimate NK lytic activity. This methodology permits the measurement of NK activity without staining the target and the measurement of perpendicular light scatter provides an alternative approach to the study of lytic processes in vitro.

Cytotoxicity, Immunologic↗
PubMed1989

[Fibrin glue in gastroenteric surgery].

In order to compare the results obtained in terminoterminal and terminolateral intestinal anastomoses using fibrin glue, both fibrin glue and the tissucol KIT were used on a group of rats: comparison of the wounds so treated revealed that both products gave good results. It is claimed that with certain technical improvements the use of fibrin glue could be extended to microsurgery of the nerves and blood vessels.

Anastomosis, Surgical↗
PubMed1989

Liposome-nucleus interactions. Flow cytometric study on the role of the nuclear surface.

The water-soluble probe carboxyfluorescein (CF), contained in the internal aqueous phase of liposomes, was used to investigate the interaction of phospholipid vesicles with isolated nuclei. Ultrastructural analysis indicated that adherent liposomes coated the nuclear surface, and fluorescence microscopy showed that they contained quenching concentrations of the dye. Flow cytometry revealed that the transfer of the entrapped dye from the adhering liposomes to nuclei was blocked by chilling at 0 degrees C. Chase experiments demonstrated that the most reliable mechanism of dye transfer involved fusion phenomena between the liposomal and the nuclear membranes. After the release of the fluorophore into the nucleus, empty liposomes could withdraw the intranuclear soluble fraction of the dye.

Animals↗
PubMed1989

Chromatin organization in rat testis nuclei. Flow cytometric detection of the morphological compaction.

The unusual histone composition of testicular cells generates changes in chromatin organization in order to allow the chromosomal pairing necessary for genetic recombination. Accessibility of testis nuclear DNA was determined by flow cytometry. The observed differences in staining between testis and liver nuclear chromatin, as well as the differences of perpendicular light scatter signal, correlate with alterations in protein composition with the chromatin reorganization.

Animals↗
PubMed1989

Improved bromodeoxyuridine/DNA analysis by anti-BudR monoclonal antibody versus right angle light scatter.

Dynamic cell cycle analysis is based on the incorporation of labelled precursors into DNA. Although antibodies to BrdU are very useful for analysing in flow cells which synthesize DNA, this approach has two main limitations. First, the detection of low incorporating cells is often difficult; second, four parameter flow cytometry is not able to correlate cell cycle to any other cellular marker. We have developed a methodology that, employing an IgGH + L as a second antibody and side scatter instead of propidium iodide fluorescence, allows a better discrimination of BudR+ cells. This approach allows the collection of an extra-fluorescent signal, and the analysis of specific cellular markers within the cell cycle.

Antibodies, Monoclonal↗
PubMed1989

Impaired lymphocyte stimulation induced by long-term training.

In recent there has been increasing interest in the definition of hormone influence on the immune system. Physical stress provides a suitable model for studying the interactions between the immune system and the neuroendocrine factors which have been shown to modulate the lymphoid cellular compartment. Our approach has been devoted to defining the stable modifications induced in the immune system in athletes during agonistic training. The results show that the circulating compartment of the immune system tends to modulate its different subsets under the continuous influence of stress hormones, together with a specific functional impairment of the helper subset in the proliferative response after stimulation with PHA, and particularly with PWM.

Antibodies, Monoclonal↗
PubMed1989

[Intramural infiltration of gastric cancer].

The relationship between the degree of intramural infiltration and the aspect and macroscopic dimensions of stomach cancer is investigated in the light of personal experience and reports in the literature. Statistics in the literature suggest that the choice between total and subtotal gastrectomy is only available in antropyloric cancers.

Duodenal Neoplasms↗
PubMed1988

Natural killer function in flow cytometry. I. Evaluation of NK lytic activity on K562 cell line.

Flow cytometry has been employed to establish an NK assay using the K562 target cell line. These cells show a perpendicular light scatter (PLS) characteristically different from lymphocytes. Other physical parameters, such as forward light scatter (FLS), do not discriminate between the two populations, since dead K562 cells display similar FLS characteristics as effector cells. Killed cells are stained with propidium iodide and followed by flow analysis. It was advisable to add the dye in the medium so that, as long as the target cells are killed they will also be stained. Moreover the flow cytometric and trypan blue evaluation of target cell death rate showed a stronger correlation than did either test with the conventional 51Cr release assay, the first two methods both being based on the same biological mechanism.

Cell Membrane Permeability↗
PubMed1988

Chromatin organization in isolated nuclei: flow cytometric characterization employing forward and perpendicular light scatter.

Flow cytometric perpendicular and forward light scatters have been employed to evaluate whether the changes in chromatin organization due to ionic strength, Mg++ concentration and pH, visible in electron microscopy, can be monitored by flow cytometry. The average intensity of the perpendicular light scatter signal increased as nuclear chromatin became decondensed by lowering the ionic strength or releasing H1 histone at low pH values. These results indicate that flow cytometry signals and in particular the perpendicular light scatter allow the detection of the conformational transitions in chromatin and may therefore be useful for studying cell cycle associated morphological changes in isolated nuclei.

Animals↗
PubMed1988

Gradient fractionation of cycling and resting cells monitored by BrdUrd incorporation.

A number of techniques are currently employed for the fractionation of heterogeneous cell populations or for the separation of cells in different phases of their cycle. With the development of osmotically inert colloidal silica particles media, density gradient centrifugation became an established method for the separation and purification of cells and subcellular particles. We have applied this technique to the separation of cycling from resting Friend erythroleukemia cells, to obtain purified populations for further biological assays. The flow cytometric analysis of DNA content of the different fractions obtained by the gradient and stained with Propidium Iodide (PI), showed the S compartment highly concentrated in the 1.073/77 g/ml interface, while the upper levels of the gradient were highly enriched of cells in G1 phase. Moreover, the dual parameter analysis of DNA content by means of Bromodeoxyuridine (BrdUrd) incorporation and PI staining, showed that part of the cells in the 1.067/73 fraction represented the early S phase even if their DNA level, measured on the basis of PI fluorescence was within the diploid cell cluster. This method seems to be suitable to obtain pure cell fractions even when dealing with numerically large populations.

Animals↗
PubMed1988

cDNA cloning and primary structure of a white-face hornet venom allergen, antigen 5.

A major allergen of white-face hornet (Dolichovespula maculata) venom is antigen 5 (also designated Dol m V). We have determined the primary structures of two forms of this protein by cDNA and protein sequencings. These two forms with 204 and 205 amino acid residues differ in 23% of their sequences but they are antigenically similar. Both forms have sequence similarity with a pathogenesis-related protein of tobacco leaf. In a 130-residue overlap of these proteins, 35-39 residues were identical. Hornet antigen 5 cDNAs were isolated from an expression library in lambda gt11 phage using antibody probes. Several of the cDNAs were not full length, but the fusion fragments expressed were immunoreactive. These results suggest that antigenic determinants of the sequential type are distributed throughout the entire molecule of antigen 5. After subcloning, antigen 5 was also expressed in pKK233-2 plasmid.

Amino Acid Sequence↗
PubMed1988

Membrane-bound immunoglobulins increase during red blood cell aging.

A flow cytofluorimetric method was used to detect the immunoglobulin molecules present on human red blood cells. Normal human erythrocytes were separated into seven fractions of increasing mean age by density centrifugation on discontinuous gradients. Some biochemical and morphological properties of these cells were determined as well as their IgG content. The results obtained suggest that IgG binding during red cell aging is a cumulative process.

Erythrocyte Aging↗
PubMed1987

Use of poligonal windows for physical discrimination among mononuclear subpopulations in flow cytometry.

Peripheral blood mononuclear cells from ten healthy normal donors were analyzed by means of monoclonal antibodies and flow cytometry (FACS IV). In order to apply optimal gating for the identification and exclusion of monocytes from lymphocyte populations, mononuclear cells were analyzed on the scattergram using rectangular or poligonal computer-generated windows. Two main windows on lymphoid population were used which mainly differed for the up-right corner, in the border area between lymphocytes and monocytes. While the number of lymphocytes contained either in the regular or in the poligonal windows was the same, the number of contaminating monocytes decreased by two-fold in the poligonal one. Besides, the use of tight lymphocyte gating, in order to reach lower monocyte contamination, leads to a loss of lymphoid cells which does not appear to be random, but seems to affect mainly the Leu11c+ population with natural killer activity. These cells produce forward and perpendicular scatter signals higher than other lymphocyte subsets, and, therefore, are mainly located in the area of the scattergram which divides lymphocytes from monocytes. These data are in accordance with the large granular morphology of natural killer cells. The use of the poligonal windows seems to be useful to reduce monocyte contamination with no selective loss of natural killer lymphocytes, and may be particularly helpful in the analysis of pathological samples.

Antibodies, Monoclonal↗