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Biomedical subjects

R Dagnino

Publications and source records attributed to R Dagnino.

5 recordsLinked to original sources
PubMed2001

1-Alkyl-3-amino-5-aryl-1H-[1,2,4]triazoles: novel synthesis via cyclization of N-acyl-S-methylisothioureas with alkylhydrazines and their potent corticotropin-releasing factor-1 (CRF(1)) receptor antagonist activities.

Cyclizations of alkylhydrazines with N-acyl-S-methylisothioureas, readily synthesized from acyl chlorides, sodium thioisocyanate, dialkylamines then methyl iodide in a one-pot reaction, gave 1-alkyl-3-dialkylamino-5-phenyltriazoles 7 as major products. The regioisomers were assigned through the use of NOE NMR experiments. While bearing a N-bis(cyclopropyl)methyl-N-propylamino group, this series of compounds shows very good binding affinity on the human CRF(1) receptor. Among them, 1-methyl-3-[N-bis(cyclopropyl)methyl-N-propylamino]-5-(2,4-dichlorophenyl)-1H-[1,2,4]triazole 7a had the best binding affinity for the CRF(1) receptor (K(i)=9 nM).

Humans↗
PubMed1989

Phosphonium salts exhibiting selective anti-carcinoma activity in vitro.

Tetraphenylphosphonium cation (TPP) and other phosphonium cations selectively inhibited the growth in vitro of human pancreatic carcinoma-derived cells (PaCa-2) and Ehrlich Lettre Ascites cells (ELA) when compared with untransformed monkey kidney epithelial cells (CV-1). In contrast, neither cisplatin nor cytosine arabinoside showed significant selectivity using these lines. Evidence is presented to support the conclusion that the carcinoma-selective antiproliferative activity of phosphonium salts is due to selective accumulation caused by the abnormally high membrane potentials in carcinoma cells. Inhibition of TPP uptake into PaCa-2 and ELA cells by potassium and (for PaCa-2) valinomycin demonstrates that higher membrane potentials account for the carcinoma-selective uptake and cytostatic selectivity of the cation. For TPP chloride and 16 other phosphonium chlorides with a variety of structures, selective inhibition of PaCa-2 growth relative to CV-1 was optimal for the eight falling in a narrow range of octanol/water partition coefficients (between 0.013 and 0.24). A similar optimal selectivity range was observed for ELA cells relative to CV-1. The relationship between partition coefficients and cytostatic selectivity suggests that the rates of diffusion across cytoplasmic and mitochondrial membranes are key factors in the structure/anticarcinoma selectivity relationship for delocalized phosphonium salts in vitro. The relationship could prove useful for the design of other carcinoma-selective delocalized cations.

Animals↗
PubMed1988

Environment-selective synergism using self-assembling cytotoxic and antimicrobial agents.

Environment-selective synergistic toxicity using combinations of aldehydes and hydrazine derivatives was demonstrated in two different model systems in vitro. Combinations of 5-nitro-2-furaldehyde with semi-carbazide and of 2-hydrazinopyridine with pyridine-2-carboxaldehyde, which can react in situ to form antimicrobial hydrazones, demonstrated greater degrees of synergism against the intracellular pathogen, Salmonella typhimurium, at pH 5 relative to pH 7.4. Combinations are more selectively toxic at pH 5 (vs pH 7.4) than individual precursors and preformed hydrazone products because acid catalysis of hydrazone formation plays a role only for the combinations. A combination of decanal and N-amino, N'-octylguanidine (AOG) exhibited more pronounced synergistic cytolytic activity against erythrocytes in 0% serum than in 1% serum. Serum protein binding of decanal inhibited the formation of the more cytotoxic hydrazone, N-decylidenimino,N'-1-octylguanidine (DIOG), from the less cytotoxic AOG and decanal, and serum protein binding of DIOG prevented this cytotoxin from reaching the cell membrane. Because decanal binding cannot play a role in the cytotoxicity of preformed DIOG, it was less selective for cells in 0% serum than the combination of AOG and decanal. The pH 5 and 0% serum environments represent very simple models for macrophage phagolysosomal compartments and poorly vascularized solid tumor interiors respectively. If environment-selective synergism can be used as a basis for target-selective synergism in other in vitro model systems and in vivo, self-assembling combinations could provide a basis for rational introduction of target-selective synergism into chemotherapeutic drug design.

Aldehydes↗
PubMed1984

Polymyositis/dermatomyositis and pregnancy.

Eighteen women with polymyositis/dermatomyositis (PM/DM) were studied to determine the possible influences of pregnancy on the disease and the influence of the disease on pregnancy. Before the onset of PM/DM there were 77 pregnancies: 7 (9%) ended in abortion, 2 (2.5%) in perinatal deaths, with a total fetal loss of 11.5%. There were 3 (3.8%) premature newborns that survived. These figures are equivalent to those of the general population. There were 10 pregnancies in 7 patients coinciding with PM/DM, 1 of them with twins; 3 (30%) ended in abortion, 3 (25%) in perinatal deaths, with a total fetal loss of 55%, and 5 (50%) pregnancies ended prematurely. Four of the 7 women had onset of PM/DM during pregnancy, and 3 others with previously inactive disease had an exacerbation during pregnancy. There were no maternal deaths, nor was there any correlation between activity of PM/DM and fetal loss. These results together with those previously reported suggest that pregnancy in PM/DM should be considered high-risk for both the mother and the baby.

Abortion, Spontaneous↗