Effect of cyclosporin A and trifluoperazine on rat liver mitochondria swelling and lipid peroxidation

The effect of cyclosporin A (CsA) or trifluoperazine (TFP) on lipid peroxidation and mitochondrial swelling was determined using liver mitochondria incubated with 30 microM Ca2+ and 250 microM t-butylhydroperoxide or 5 mM inorganic phosphate (P(i)). Lipid peroxidation was not modified by either 1 microM CsA or 40 microM TFP. These compounds presented a distinct effect on mitochondrial permeability. Under oxidative conditions, CsA only showed a transient protective effect whereas TFP completely inhibited mitochondrial swelling. Conversely, CsA was very efficient when Ca2+ and P(i) were used, a condition under which TFP was unable to prevent the swelling. These data are consistent with our previous results (M.F. Nepomuceno, D.V. Macedo and L. Pereira-da-Silva (1991). Brazilian Journal of Medical and Biological Research, 24: 833-836) showing that lipid peroxidation is one among other different components of the permeabilization process. The data suggest that lipid peroxidation is independent of swelling, occurring later than swelling, presumably when the mitochondrial reductant systems are depleted. The differential effects of CsA and TFP suggest that these compounds can be used as specific probes in the elucidation of the two distinct mechanisms responsible for mitochondrial swelling

Studies on the utilization of inorganic pyrophosphate by different metabolic systems in yeast mitochondria

A mitochondrial pyrophosphatase (PPase) from yeast cells (Saccharomyces cerevisiae) was studied and characterized. The hydrolytic activity towards inorganic pyrophosphate (PPi) was inhibited by different SH-reagents and increased in the presence of uncouplers, indicating a possible involvement of this enzyme in energy-linked processes. This view was also supported by the observation that these mitochondria were able to hydrolyze PPi, generating an electrical membrane potential (delta psi) of the same magnitude as that obtained with ATP. Both ATP and PPi inhibited the pyruvate dehydrogenase complex and it was demonstrated that PPi can be used as substrate by mitochondrial kinases leading to the same pattern of protein phosphorylation as when ATP is used

Apresentacao e evolucao ecografica raras do hematoma das supra-renais em recem-nascido / Presentation and evolution echografic rares of the hematoma of the adrenal glands in infant newborn

Os autores descrevem um caso de hematoma bilateral das supra-renais no recem-nascido, cuja exuberancia dos aspectos imagiologicos contrastou com uma excelente evolucao clinico-biologica. A proposito, discutem a sequencia de imagens ecograficas que, neste caso, se mostrou fora do habitual .

Comparison of the antiviral activity and toxicity of a protein magnesium ammonium phospholinoleate anhydride polymer with other antiviral drugs

1. SB-73, a magnesium ammonium phospholinoleate anhydride aggregate, exhibited antiviral action in vitro in the concentration range of 50 to 100 µg/ml against herpes simplex type 1, stomatitis vesicular virus, adenovirus type 5, and in vivo in the dose range of 0.7 to 1.3 mg/Kg against canine parvovirus distemper virus. 2. The lethal dose (LD50) was 2.71 ñ 1.55 g/Kg body weight in mice inoculated intraperitoneally. Oral ingestion of the aggregate up to 30 g/Kg body weight by mice had no lethal effects during the 14 days of observation. 3. In in vitro cytotoxicity experiments with fibroblasts (V-79 Chinese hamster cell line), no toxic effects were observed with SB-73 concentrations (120 µg/ml) having antiviral activity. 4. In a cellular proliferation experimental using hamster V-79 cells, we observed 72% proliferation after treatment of the cells with a high concentration (500 µg/ml) of SB-73. 5. Compound SB-73 showed no genotoxicity for human lymphocytes at concentrations of 100 µg/ml. 6. When the cytoxicity and genotoxicity of SB-73 wee compared with those of acyclovir, idoxuridine and AZT at 500µg/ml concentration the compound was found to have effects similar to those of acyclovir