Effect of ethanol exposure on Xenopus embryo lipid composition.

Exposure to ethanol is known to alter cell membranes both chemically and biophysically; these effects may be related to the development of tolerance and physical dependence. In the present study, the effects of various concentrations of ethanol (1-250 mM) on the lipid composition after the first 6 days of Xenopus embryo development were investigated, using an in vitro fertilization technique. Lipid analysis revealed: (1) a decrease of the cholesterol/phospholipid molar ratio mainly derived from a higher content of phospholipids; (2) an increase of phospholipid unsaturated fatty acids, especially C20:4 and C20:5, with ethanol concentration of 150-250 mM; (3) a decrease of lipid-bound sialic acid with ethanol concentrations of > or =5 mM.

Rat erythrocyte susceptibility to lipid peroxidation after chronic ethanol intake.

Erythrocytes, from 2- and 7-month-old rats chronically fed with a liquid diet containing ethanol, were analyzed for their susceptibility to lipid peroxidation estimated as thiobarbituric acid reactive substance (TBARS) products. In spite of a lower alcohol consumption, adult rats were the more affected by the ethanol treatment. Erythrocyte membranes prepared from alcoholic animals were more sensitive to lipid peroxidation than those prepared from control rats.

Age-related effects of chronic ethanol intake on physical properties, lipid composition and galactosyltransferase activity of rat small intestine microsomes.

The effect of a 4-week ethanol administration on: (1) glycoprotein content of brush border membrane (BBM): (2) galactosyltransferase activity; (3) lipid composition and fluidity of intestinal microsomes prepared from young and adult rats was investigated. In spite of a lower alcohol consumption, the more dramatic effects of treatment have been observed in the older rats, where BBM protein-bound hexoses and microsomal galactosyltransferase activity were significantly decreased. On the contrary, these parameters were unaffected in young rats.

Age related changes in functions and physicochemical properties of rat jejunal brush border membrane after chronic ethanol administration.

1. We investigated the chronic effects of a 4 week treatment with ethanol on functions and physicochemical properties of BBM of young and adult rats (2 and 7 months old respectively). 2.

Role of phosphatidylethanol in membranes. Effects on membrane fluidity, tolerance to ethanol, and activity of membrane-bound enzymes.

We investigated the effect of phosphatidylethanol (PEt) on fluidity and membrane tolerance to the fluidization induced by ethanol as well as on the activity of two membrane-bound enzymes, Na+/K+ ATPase and 5'-nucleotidase. PEt was synthesized from 1,2-dimyristoylphosphatidylcholine and phosphatidylcholine from bovine brain and studies were performed to determine the optimal experimental conditions for the insertion of PEt in natural bilayers. The effects of PEt, evaluated by differential scanning calorimetry or fluorescence polarization techniques, were studied in model membranes made of synthetic phospholipids or made of total lipids extracted from rat brain crude mitochondrial fraction (P2 fraction) and from natural membranes (P2 fraction).

L-carnitine and carnitine ester transport in the rat small intestine.

L-carnitine and its esters (acetyl-L-carnitine and propionyl-L-carnitine) at pharmacological doses (1, 5 and 10 mM) are absorbed by the rat jejunum by simple diffusion. Partition coefficients of carnitine esters determined in lipophilic media (diethyl ether/water and olive oil/water) are greater than that of L-carnitine. It would therefore seem that esters diffuse more easily through the lipid component of the intestinal barrier.

Postnatal maturation of rat intestinal membrane: lipid composition and fluidity.

1. We studied the lipid composition and the fluidity of small intestine brush border membrane (BBM) of rats of different age: 'very young' (5-7 weeks old), 'young' (9 weeks old), 'adult' (30 weeks old) and 'old' (85 weeks old). 2.

Effects of cholesterol and alfa-2-recombinant interferon on cell growth and cell antigen production in the HT 29 cells, an established cell line of human colon adenocarcinoma.

HT 29 cells, an established cell line of human colon adenocarcinoma, were grown in RPMI 1640 medium without or with cholesterol at 25, 50, 100 micrograms/ml concentrations. In some experiments 100 or 200 U/ml alfa-2-A recombinant Interferon were added to the medium. Only in the case of the highest cholesterol concentration there was a reduced number of cells at confluence.

Effects of semistarvation on transintestinal D-glucose transport and D-glucose uptake in brush border and basolateral membranes of rat enterocytes.

The present work shows that semistarvation (8-10 g of food for 10 days) increases net D-glucose, Na+ and water transport in the everted and perfused rat jejunum. A linear and positive correlation between cell sugar concentration and transport was found in control and semistarved rats, but the phenomenon was more relevant only in semistarved animals. Membrane vesicle experiments showed that semistarvation increases sugar overshoot only in brush border membrane vesicles, while this situation does not occur in basolateral membrane vesicles.

Intestinal sugar transport during ageing.

Ageing effects on sugar intestinal transport were studied by using the everted sac and the brush-border membrane vesicle techniques. Four age groups of rats were used: very young, young, adult and old animals. Net transintestinal transport of D-glucose and intracellular sugar accumulation were greater in young than in very young, adult and old rats.

Effect of maternal diet on ganglioside distribution in fetal rat brain.

Female rats were fed a diet with low protein content or with low and high amount of essential fatty acids (EFA). Ganglioside content and distribution were analyzed in the brain of animals at two different periods of fetal life (15th or 20th day). In the fetuses from mothers fed the diet with low amount of EFA the content of ganglioside is significantly lower than in the control group.