170,017 research outputs found
Carlo Flamigni - Corrado Melega, "La cronologia della sperimentazione sull\u27uomo"
No full textReview of the book "La sperimentazione sull\u27uomo" by C. Flamigni and C. Melega.Recensione del volume "La cronologia della sperimentazione sull\u27uomo" di C. Flamigni e C. Melega
Temi eticamente sensibili e libertà di coscienza : note a margine del libro di Flamigni e Mori sulla legge 40
No full textThe paper discusses the new book by Carlo Flamigni
and Maurizio Mori suggesting that
one of the powerful ideological support to Italian law on assisted reproductive tecnology (Legge
40/2004) has been the union of the idea of ethical sensitive issues with a wrong interpretation of
freedom of conscienc
Le nuove sfide della bioetica: gentica, riproduzione e cura tra filosofia, etica pubblica e diritti. Introduzione.
No full textInhibition of the expression of ornithine decarboxylase and c-Myc by cell-permeant ceramide in difluoromethylornithine-resistant leukaemia cells.
No full textCeramide has emerged as a novel lipid mediator in cell growth and apoptosis. In difluoromethylornithine-resistant L1210 cells stimulated to growth from quiescence, the cell-permeant analogues of ceramide N-acetylsphingosine (C2-ceramide) and N-hexanoylsphingosine (C6-ceramide) inhibited the induction of ornithine decarboxylase (ODC) activity with IC50 of 8.3 and 1.5 microM respectively. This effect was strictly related to the ability to inhibit cell growth and [3H]thymidine incorporation. The suppression of cell growth was also associated with apoptosis. The addition of bacterial sphingomyelinase resulted in a significant, but limited, reduction of ODC induction and [3H]thymidine incorporation. Bacterial lipopolysaccharide, which may act as a ceramide analogue, also inhibited the induction of the enzyme. Moreover, C6-ceramide largely prevented the accumulation of ODC mRNA and its precursor, ODC heterogeneous nuclear RNA, that accompanied the induction of ODC activity. A slight increase in ODC turnover was also observed. The DNA-binding activity of some transcription factors known to bind and transactivate the ODC gene was investigated by gel mobility-shift assay under the same experimental conditions. However, only the binding of Myc/Max was negatively affected by the treatment with C6-ceramide. Furthermore, the amount of immunoreactive c-Myc, which increased after stimulation of the cells to growth, was strongly reduced by C6-ceramide. These results suggest that the inhibition of c-Myc and ODC expression may be early events in the response of leukaemia cells to ceramide.IF 5.01
Tra schiavitù e libertà : status e diritti nello spazio caraibico, XIX secolo
No full textIn 1843, six free Blacks from Jamaica were accused of abolitionist propaganda in Spanish
Cuba. At the same time, some men and women in bondage applied to the British Consulate
in Havana to have their free status recognized. In the XIX century, the revolts against the
institution of slavery multiplied, raising the spectre of the Haitian revolution in the Atlantic
world. Based on materials collected in European colonial archives (Madrid, London, and
Aix-en-Provence), this paper deals whit the anti-slavery conflicts and the legal battles for
the recognition of freedom in the Caribbean empires. The access to new statuses and rights
by enslaved people questions different forms of resistance to slavery in the complex
dialogue between collective insurrections and individual struggles
Involvement of thiol transferase- and thioredoxin-dependent systems in the protection of 'essential' thiol groups of ornithine decarboxylase
No full textOrnithine decarboxylase (ODC), an enzyme with 'essential' thiol group(s), may be inactivated in vitro by removal of thiol reducing agents and re-activated by soluble factors from rat liver in the presence of NADPH or GSH. The NADPH- and GSH-dependent reducing systems were sepated and resolved into three components, called factors A, B1 and B2, by chromatographic techniques. Factor B1 (M(r) 12000) could reactivate ODC in the presence of GSH of co-purified with thiol transferase activity. Factor B2 (M(r) 12000) and factor A (M(r) approx. 110000) were both needed to re-activate ODC in the presence of NADPH, and co-purified with thioredoxin and thioredoxin reductase activity respectively. In an attempt to investigate the physiological role of the 'essential' thiol group(s) of ODC, erythroleukemia cells were incubated with NN-bis-(2-chloroethyl)-N'-nitrosourea, t-butyl hydroperoxide and vinblastine, which are known to increase the cellular GSSG/GSH ratio, azelaic acid, an inhibitor of thioredoxin reductase, and sodium arsenite, a strong inhibitor of the ODC-re-activating factors. All these compounds were able to decrease significantly the ODC activity induced in these cells. These results suggest that the thiol transferase- and thioredoxin-dependent systems may be physiologically relevant in maintaining ODC in the active, reduced, state
Effect of sodium arsentie on the induction and turnover of ornithine decarboxylase activity in erythroleukemia cells
No full textSodium arsenite proved effective in preventing the induction of ornithine decarboxylase (ODC) activity elicited by dilution of Friend erythroleukemia cells in fresh medium. A 50 per cent inhibition was produced at approximately 1 μM arsenite and complete inhibition was obtained at concentrations above 10 μM. However, addition of arsenite 5 h after cell dilution, i.e. when ODC was already induced, appeared to stabilize the enzyme. The half‐life of ODC activity, measured after cycloheximide treatment, increased almost six‐fold after addition of sodium arsenite. Agents known to provoke oxidative alteration of the thiol‐redox status in cells, also caused a similar effect on the induction and stability of ODC. Copyright © 1989 John Wiley & Sons Ltd
Stabilization of ornithine decarboxylase in erythroleukemia cells depleted of ATP
No full textOrnithine decarboxylase activity in Friend erythroleukemia cells decayed with a half-life of 50 minutes after addition of cycloheximide and at a faster rate after addition of spermidine. Incubation with a medium containing dinitrophenol and 2-deoxyglucose in place of glucose caused ATP depletion and blocked the turnover of ornithine decarboxylase, even after addition of spermidine. Dinitrophenol in the presence of glucose was able to provoke only a slight increase of the half-life of the enzyme. These results suggest that degradation of ornithine decarboxylase in erythroleukemia cells is ATP-dependent. © 1989
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