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Biomedical subjects

I Galatulas

Publications and source records attributed to I Galatulas.

99 records · Page 6Linked to original sources
PubMedDate not supplied

Reduction of adriamycin cardiotoxicity by enoximone.

Several non catecholamine, non glycoside cardiotonic drugs have been described recently. New compounds include amrinone, sulmazole, milrinone and pimobendan. In an attempt to alleviate or prevent anthracycline toxicity, we have reported that these compounds reduce the negative effects of adriamycin, 4-epiadriamycin and esorubicin in isolated guinea pig atria. The present study reports the effects of a new cardiotonic agent: enoximone. Enoximone was administered after adriamycin (100 micrograms/ml) on the isolated and spontaneously beating atria, and on electrically driven left atria of guinea pig-in normodynamic and hypodynamic conditions. Exposure for 60 minutes to the antitumor drug causes a depression of contractile force (g) and its derivative versus time (dF/dt, as maximal rate of contractile force). The negative effects of adriamycin are antagonised by enoximone (100, 200 micrograms/ml).

Animals↗
PubMedDate not supplied

Synthesis and cytotoxic activity of peptides containing basic amino acids residues.

We synthesized eight peptides containing from three to twenty residues of arginine, lysine and histidine, using an automated synthetiser and Fmoc strategy. All peptides were purified by preparative reverse-phase HPLC and characterized by electrospay mass spectometry. Cytotoxic activity was assessed on HeLa cells. One peptide inhibited the colony-forming ability of tumor cells.

Amino Acid Sequence↗
PubMedDate not supplied

Antitumor activity of an alkylating derivative of dipyridamole.

Synthesis of 2,6-Bis[bis(2-chloroethyl)amino]-4,8-dipiperidino-pyrimido [5,4-d]pyrimidine (DIP-C1) was carried out, and the new derivative showed cytotoxic activity comparable to other alkylating drugs on cultured P388 leukaemia cells and HeLa cells. The present paper reports the effects of DIP-C1 on respiration of Ehrlich ascites tumor cells and on survival of the mice implanted with Ehrlich ascites tumor cells. The compound showed a significant activity in both experimental models.

Animals↗
PubMedDate not supplied

Influence of antimalarials chloroquine, quinine, primaquine and mepacrine on the evolution of Ehrlich ascites tumour.

Substances like imidazoles, benzimidazoles and also quinolines, whose chemical structure includes a heterocyclic nitrogen, are known to interfere with the microsomal oxidation and, in some cases, with the metabolism of drugs. Since chloroquine and primaquine exert this effect in vivo and in vitro, we studied the influence of other antimalarials (quinine and mepacrine) in mice with induced Ehrlich ascites tumour (EAT) to find out whether variations in oxygen consumption affected the course of the disease. In vitro data, obtained by a polarographic technique, indicate that primaquine and, in particular, mepacrine increase EAT-cell oxygen consumption, while in vivo data, obtained in mice injected with an inoculum of about 1 x 10(6) tumour cells per mouse, show that both drugs, but notably mepacrine, accelerate tumour growth, as monitored by Cox's statistical method for body weight, and lead to earlier death. In cases of existing neoplasia, therefore, the potentially toxic effects of certain antimalarials must be borne in mind.

Animals↗
PubMedDate not supplied

Enhancement of cytotoxic activity by synthesis of peptide multimeric forms.

Synthesis of four multimeric H-Lys-His-His-Arg-Lys-Lys-His-Arg-Lys-Arg-Lys-His-His-Lys-Arg-Lys-oH peptides containing two, four, eight and sixteen branches was carried out by solid phase utilizing a lysine core matrix. These multimeric peptides enhanced activity by inhibiting the colony-forming ability of HeLa cells, from twenty-four to fifty-six times in comparison with the monomeric form. Unexpectedly the peptide with only two-branched sequences showed the highest inhibitory activity.

Amino Acid Sequence↗
PubMedDate not supplied

Role of chemotherapeutic antagonism in opportunistic infections.

The most widely-known anti-tumor drugs often induce marked immunosuppression which can give rise to one or more sepses. Anti-infection measures immediately applied can sometimes prove largely ineffective or even useless, the patient dying not as a result of the spread of the tumour but as a direct consequence of opportunistic infection. We postulate that antagonism between anti-tumour and antimicrobial drugs may also play an important part in this. By way of illustration of this hypothesis, we have studied the action of a number of known inhibitors of peptidoglycan synthesis and of DNA-gyrases on certain strains of Gram-positive and Gram-negative microorganisms cultured in medium containing various concentrations of some of the best-known anti-tumour antimetabolites. The experimental data show that antimicrobial and anti-tumour drugs can sometimes induce synergic or indifferent chemotherapeutic interactions with many bacteria, while in others the effect is antagonistic. In practice, the action of the drugs could lead to bacterial selectivity, which, in conjunction with immunosuppression and the presence of resistant strains, could favour the evolution of opportunistic infection.

Anti-Bacterial Agents↗
PubMedDate not supplied

Synthesis and cytotoxic activity of new peptides containing basic amino acid residues.

In search of more potent compounds endowed with a cytotoxic activity, a new series of basic peptides was synthesized using solid-phase methods. All peptides were purified by preparative reverse-phase HPLC and characterized by electrospray mass spectrometry. The cytotoxic activity was determined in cultured HeLa cells. The hexadecapeptides 5 and 6 showed a 50% inhibition at the concentration of 30 micrograms/ml. The salmina and the polyamino acids of L-arginine, L-histidine and L-lysine, containing sixteen residues, were virtually inactive. This demonstrates that a specific peptide sequence is necessary to obtain a positive response in HeLa test.

Amino Acid Sequence↗
PubMedDate not supplied

Potential coanthracyclinic activity of pyridylmethylene-2-indolinones.

The paper reports the cytotoxic activity of pyridylmethylene-2-indolinones previously described as cardiotonics and the synthesis of three analogs of the most potent cytotoxic agent. Some of these compounds could be useful, when associated with anthracyclines, to reduce the cardiotoxicity of these potent antitumor drugs.

Antineoplastic Agents↗