Effect of ethanol on human colon carcinoma CaCo-2 and HT-29 cell lines during the maturation process.

The aim of the study was to ascertain whether the exposure to ethanol of human colon carcinoma CaCo-2 and HT-29 cell lines affects the differentiation process. As an index of enterocytic differentiation, the expression of sucrase, alkaline phosphatase, alpha 2,6-sialyltransferase toward the N-acetyllactosaminic sequence, and beta 1,4-N-acetylgalactosaminyltransferase (beta 1,4GalNAc-transferase) was examined. The latter enzyme is responsible for the biosynthesis of Sda carbohydrate histo-blood antigen, which mainly occurs in human colonic cells; its expression in CaCo-2 cells depends strictly on the enterocytic differentiation. The addition of ethanol in the culture medium resulted in a significant increment of sucrase and alpha 2,6-sialyltransferase activities in both cell lines, as well as the beta 1,4GalNAc-transferase activity in CaCo-2 cells and alkaline phosphatase activity in HT-29 cells. The increment was dose-dependent in the range between 50 and 200 mM ethanol and evident after 2 days of exposure in both cell systems. These results support the notion that, as occurs for cell lines of different origin, the ethanol in vitro positively affects the differentiation of intestinal cells, namely along the enterocytic lineage. The putative mechanism by which ethanol interferes with the maturation process of colonic cells is discussed.

Xanthine oxidase status in ethanol-intoxicated rat liver.

The status of xanthine oxidase in ethanol-induced liver injury has been investigated in the rat, by acute and chronic ethanol treatments. A 38% increase of the enzyme O-form was observed after repeated ethanol administration. Chronic intoxication caused a significant decrease of total xanthine oxidase activity after both prolonged ethanol feeding and life span ethanol ingestion. The intermediate D/O-form of xanthine oxidase (that can act either as an oxidase or as a dehydrogenase, being able to react with O2 as well as with NAD+ as electron acceptor) increased 5.5-fold after prolonged ethanol feeding.

Effect of acute and chronic ethanol administration on rat liver alpha 2,6-sialyltransferase activity responsible for sialylation of serum transferrin.

The effect of a single administration and a 6-week treatment with ethanol on rat liver sialyltransferase activity towards asialoglycoproteins and N-acetyllactosamine (Gal beta 1,4GlcNAc) was studied. Since only the alpha 2,6-sialyltransferase is involved in the in vivo sialylation of transferrin, Gal beta 1,4GlcNAc was chosen as an acceptor and alpha 2,6-sialyl-N-acetyllactosamine was separated from the corresponding alpha 2,3-sialyl isomer present in the sialyltransferase reaction mixture by high-performance liquid chromatography. After a single ethanol administration there was a low (about 20%) but significant (p less than 0.005) reduction of sialyltransferase activity towards asialotransferrin as well as a reduced alpha 2,6-sialyltransferase activity towards N-acetyllactosamine. An opposite result was found in the chronically ethanol-treated rats: in these animals either the total or alpha 2,6-sialyltransferase activity was slightly higher than in control animals. Blood ethanol concentration was significantly high (3.3 +/- 1.2 mg/ml) only in the acute-treated animals, suggesting that the accumulation in the body of ethanol and/or its metabolites induces a reduction of liver alpha 2,6-sialyltransferase activity responsible for the transferrin sialylation. Current results are consistent with the finding (Stibler H, Hultcrantz R: Alcohol Clin Exp Res 11:468-473, 1987) that an enhanced level of hyposialylated transferrin isoforms is a marker of present but not previous alcohol abuse.

[Acetylcholine-angiotensin interaction on the electric activity of teniae coli]. / Interazione acetilcolina-angiotensina sull'attività elettrica della "Taenia-coli".

It was tested on guinea-pig "Taenia-Coli" the interaction between ATN II and Ach in order to elucidate if there is an antagonism or an independence in the action of the two substances. It was concluded that there is no antagonism but a certain degree of interference.

[Angiotensin II-acetylcholine interaction on the mechanical response of the isolated rat stomach]. / Interazione angiotensina II - acetilcolina sulla risposta meccanica dello stomaco isolato di ratto.

This research was carried on denervated isolated rat stomach. Mechanical response to Ach treated with three different ATN II concentrations was recorded. No competitive antagonism was observed so that no common receptor can be supposed. The apparent noncompetitive antagonism may be ascribed to the action of ATN II on P and T Ca++ activating systems.

[Avoidance learning in rats treated with estrogens]. / Condizionamento di evitamento in ratti trattati conestrogeni.

Male and female rats were treated with estradiol benzoate in the 5 degrees day of life. The avoidance conditioning, tested after 65 days, was significatively impaired in males treated with estradiol, a significative retardation was observed in females treated, but no significant end-difference versus no-treated females. It is supposed that a hormone induced synaptic shaft/spines ratio in preoptic area may be involved in avoidance conditioning.

Effect of n-dipropylacetate and L-glutamine on gamma amino-n-butyric acid levels in brains of rats intoxicated with ethanol.

The concentrations of gamma-amino-n-butyric acid in brains of rats intoxicated with half intraperitoneal LD50 ethanol were determined at various times and found increased at early times (10 min) and decreased later (1 to 3 hours). The concentration tended to be restored to normal values upon administration of n-dipropylacetate (400 mg/kg) or L-glutamine (340 mg/kg). The treatment with both substances showed a positive interaction with an overall positive effect greater than the sum of each.