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T Giraldi

Publications and source records attributed to T Giraldi.

At least 73 records · Page 4Linked to original sources
PubMed1980

Synthesis of 1-aryl-3-formyl-3-methyltriazenes, potential metabolites of 1-aryl-3,3-dimethyltriazenes.

Some para-substituted 1-aryl-3,3-dimethyltriazenes were oxidized with tert-butyl hydroperoxide in the presence of vanadium pentoxide as a catalyst. Under these conditions, the corresponding 1-aryl-3-formyl-3-methyltriazenes, 1-aryl-3-tert-butylperoxymethyl-3-methyltriazenes, and p-nitrobenzenes were obtained. The 1-aryl-3-formyl-3-methyltriazenes might play a role in the metabolic oxidation of the 1-aryl-3,3-dimethyltriazenes, which are active as mutagenic, carcinogenic, and antitumor agents.

Triazenes↗
PubMed1978

Antitumor action of rhodium (I) and iridium (I) complexes.

Several rhodium(I) and iridium(I) complexes displayed different degrees of antitumour activity when tested in mice bearing Ehrlich ascites carcinoma. Rhodium (I) and iridium (I) acetylacetonate derivatives caused a high percentage of cures. The rhodium (I) dimers were particularly interesting, since (bis(cycloocta-1,5-diene)micromicron' dichlorodirhodium(I) [RhCODCl]2) was highly effective, whereas its analogues, bis(bicyclo[2,2,1]hepta-2,5-diene)micromicron'-dichlorodirhodium(I) [RhNBDCl]2) and bis(1,5-hexadiene)micromicron' dichlorodirhodium(I) [RhEDCl]2) were virtually inactive. The absence of significant inhibition of DNA, RNA and protein syntheses in tumour cells found for [RhCODCl]2 at therapeutically active dosages, indicates that this substance has a different mechanism of action from that of cis-dichlorodiammine Pt(II) (cis-PDD). The amount of rhodium found in tumour cells after administration of active [RhCODCl]2 was higher than that for [RhEDCl]2, while the rhodium concentration in the ascitic fluid was much higher for [RhEDCl]2. A mechanism based on the chemical properties of the complexes is tentatively proposed for explaining these findings and selective toxicity for tumour cells.

Animals↗
PubMed1978

Antimetastatic action of some triazene derivatives against the Lewis lung carcinoma in mice.

Two dimethyltriazenoimidazoles, DTIC and BRL 51308, and a benzenoid dimethyltriazene, CB 10286, have been examined for their effects in mice bearing Lewis lung carcinoma. A slight reduction of primary tumor growth was found after treatment with DTIC and BRL 51308, whereas CB 10286 caused no significant effect. On the contrary, all the tested compounds sharply reduced the number of lung metastases and also resulted in a high proportion of animals free of metastases at death. No significant cytotoxic effect of the triazenes was observed in small established pulmonary tumors, as determined by evaluating the effects of treatment on the fractional incorporation of 3H-TdR into DNA of the lung colonies. These results are in contrast to those obtained with a purely cytotoxic agent, cyclophosphamide, and indicate that all three triazene derivatives tested have selective antimetastatic properties.

Animals↗
PubMed1977

Preparation and antitumor activity of 1-aryl-3,3-dimethyltriazene derivatives.

Several 1-aryl-3,3-dimethyltriazene derivatives have been synthesized and tested for their antitumor activity against the TLX5 lymphoma in mice. These compounds are characterized by the presence of a carbonyl group bound to the benzene nucleus in the para position to the triazene funciton. Three p-sulfamoyl derivatives have also been included and proved to be inactive. Among the carbonyl derivatives compounds 1 and 20, which can be used as reference, cause ILS of about 50%, respectively, at four and three dose levels. Compound 16, the o-nitro-phenylhydrazone of the hydrazide 1, is active at all six dose levels studied. The adduct 19, obtained from the same hydrazide and p-nitrobenzaldehyde, is active at four dose levels, and the ILS values at two optimum doses are significantly greater than those caused by compound 1.

Animals↗
PubMed1977

Antimetastatic effects of N-diazoacetyl-glycine derivatives in C57BL mice.

When three diazoacetyl-glycine derivatives, N-diazoacetyl-glycine amide (DGA), N-diazoacetyl-glycine hydrazide (DGI), and N-diazoacetyl-glycine ethyl ester (DGE), were tested against Lewis lung carcinoma in C57BL mice, DGA reduced sharply the number and weight of pulmonary metastases; the effects of DGI and DGE were less pronounced. The growth of the primary tumor was reduced slightly by DGA, but the greater effect was produced by DGI. The absence of correlation between the reduction of the growth of the primary implant and the number of lung secondary tumors for the tested compounds indicated that DGA possesses antimetastatic properties.

Animals↗
PubMed1976

Antitumor activity of equinatoxin.

Equinatoxin, a highly basic protein extracted from Actinia equina, causes an increase in the survival time of mice bearing the ascitic form of Ehrlich carcinoma, whereas it has no effect on L1210 leukaemia. When tested for in vitro cytotoxicity by the dye exclusion test, it shows a potent activity on both tumour cell lines, with ED50 of a few ng/ml. Higher concentrations produce an extensive lysis of the cells. The cytotoxic effects of Equinatoxin are inhibited by phospholipids, thus suggesting that its mechanism of action may be related to interactions with lipids or other charged components of cell membrane. The observed lack of in vivo activity against L1210 leukaemia presumably is due to poor systemic absorption of the protein and/or neutralization by serum factors.

Animals↗