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D Fumarola

Publications and source records attributed to D Fumarola.

At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

[Bacteriocins as cytotoxic agents in experimental neoplasms: considerations on the role of possible contaminants].

In most recent papers some Authors have demonstrated that several bacteriocins are able to markedly inhibit the division of various neoplastic mammalian cell lines; also in vivo the inhibition of tumor growth or even regression relative to controls are statistically significant. Since such preparations are "crude" and it's possible that contaminating agents may represent a possible source of variability in the results, mostly in vivo; we have examined a preparation of Pyocin employed in this study for the possible endotoxin contamination using the Limulus assay. Such test was positive in triplicate and semiquantitative determination has shown and endotoxin amount of 5 to 10 microgram/ml. This level is, in vitro, not anough to give cytotoxic effect, but in vivo is able to influence experimental results. In addition, since some bacteriocins and enterotoxins are produced under exactly identical conditions, there is this a possibility that the enterotoxin are coproduced in these preparations and are causing some of the cytotoxic effects on experimental tumors. A more complete separation and purification of preparations will be required before definitive comments.

Animals↗
PubMedDate not supplied

Percoll density gradient centrifugation. (An improved method for the enrichment of lymphocyte subsets mediating different activities).

Lymphocyte fractions obtained by Percoll density gradient centrifugation were assayed for their cytotoxic activities both in NK and ADCC cytotoxic systems. Furthermore, the release of a mediator, platelet slowing factor from the same subsets, was evaluated. Different mitogens (phytohemagglutinin, concanavalin A and lipid A) have been used for this purpose. The maximum of cytotoxic activities was recovered in E+ cell-enriched fractions. On the other hand, lipid A was able to stimulate the PSF production from enriched B cells (fraction I); phytohemagglutinin induced the release of PSF from E+ fractions (II and III) and concanavalin A from fraction II only. Our results suggest that Percoll density gradient is a very reproducible method in obtaining lymphocyte subsets enriched in cells mediating either cytotoxic activities or lymphokine release.

Antibody-Dependent Cell Cytotoxicity↗
PubMedDate not supplied

In vitro effect of Leptospira icterohaemorrhagiae on human mononuclear leukocytes: comparison of virulent with non virulent strain.

The in vitro effect of a virulent and a non virulent strain of Leptospira interrogans serotype icterohaemorrhagiae on human peripheral mononuclear cells was investigated. After addition of bacteria to citrated whole blood the production of mononuclear cell procoagulant activity (tissue factor) was observed. Indeed mononuclear cells isolated from whole blood-bacteria mixtures after prolonged incubation shortened the recalcification time of normal plasma. The virulent strain induced a significantly higher procoagulant activity than non virulent and this effect was dependent on the number of bacteria. The production of tissue factor, a potent trigger of blood clotting, by Leptospira icterohaemorrhagiae could help to understand the mechanism(s) responsible for the activation of intravascular coagulation sometimes associated with leptospirosis.

Blood Coagulation Factors↗