Ana María Aguilera

Influence of copper-(II) on colloidal carbon-induced kupffer cell-dependent oxygen uptake in rat liver: Relation to hepatotoxicity

Formation of reactive O2 species in biological systems can be accomplished by copper-(II) (Cu2+) catalysis, with the consequent cytotoxic response. We have evaluated the influence of Cu2+ on the respiratory activity of Kupffer cells in the perfused liver after colloidal carbon infusion. Studies were carried out in untreated rats and in animals pretreated with the Kupffer cell inactivator gadolinium chloride (GdCl3) or with the metallothionein (MT) inducing agent zinc sulphate, and results were correlated with changes in liver sinusoidal efflux of lactate dehydrogenase (LDH) as an index of hepatotoxicity. In the concentration range of 0.1-1 microM, Cu2+ did not modify carbon phagocytosis by Kupffer cells, whereas the carbon-induced liver O2 uptake showed a sigmoidal-type kinetics with a half-maximal concentration of 0.23 microM. Carbon-induced O2 uptake occurred concomitantly with an increased LDH efflux, effects that were significantly correlated and abolished by GdCl3 pretreatment or by MT induction. It is hypothesized that Cu2+ increases Kupffer cell-dependent O2 utilization by promotion of the free radical processes related to the respiratory burst of activated liver macrophages, which may contribute to the concomitant development of hepatocellular injury.

Placental phospholipid composition, impact of maternal nutritional status

Abstract The influence of moderate maternal malnutrition on phospholipids and in the content of different types of fatty acids of the total placental phospholipids was investigated. Analysis of placental tissue lipids demonstrated that moderate maternal malnutrition increased total lipids when expressed per mg DNA. The rise in total lipid was due mainly to an increase in phospholipids and sterols content. The increase in phospholipid content was due primarily to phosphatidylcholine, phosphatidylinositol and sphingomyelin. Fatty acid composition of placental phospholipids showed marked differences between the malnourished and the control group. In the placentas of the malnourished group, phospholipids showed and accumulation of saturated fatty acid (14:0) and retention of highly insaturated fatty acids of the n3 and n6 series. These findings suggest that placenta of malnourished pregnant women suffer an alteration of phospholipids composition which may have functional significance for this organ and for fetal growth.