Glycosylation is altered by ethanol in rat hippocampal cultured neurons.

Aims: Glycoproteins, such as adhesion molecules and growth factors, participate in the regulation of nervous system development. Ethanol affects the synthesis, intracellular transport, distribution, and secretion of N-glycoproteins in different cell types, including astrocytes and hepatocytes, suggesting alterations in the glycosylation process. We analysed the effect of exposure to low doses of ethanol (30 mm, 7 days) on glycosylation in cultured hippocampal neurons.

Ethanol impairs monosaccharide uptake and glycosylation in cultured rat astrocytes.

Astrocyte and glial-neuron interactions have a critical role in brain development, which is partially mediated by glycoproteins, including adhesion molecules and growth factors. Ethanol affects the synthesis, intracellular transport, subcellular distribution and secretion of these glycoproteins, suggesting alterations in glycosylation. We analyzed the effect of long-term exposure to low doses of ethanol (30 mm) on glycosylation process in growing cultured astrocytes in vitro.

Endocytosis and transcytosis in growing astrocytes in primary culture. Possible implications in neural development.

Endocytosis constitutes an essential process in the regulation of the expression of cell surface molecules and receptors and, therefore, could participate in the neural-glial interactions occurring during brain development. However, the relationship between endocytic pathways in astroglial cells under physiological and pathological conditions remains poorly understood. We analyzed the endocytosis and transcytosis processes in growing astrocytes and the possible effect of ethanol on these processes.

Effect of tert-butyl hydroperoxide addition on spontaneous chemiluminescence in brain.

It is well known that light emission is related to lipid peroxidation in biological material, and that this process occurs spontaneously in the brain. tert-Butyl hydroperoxide (tBHP) is an organic peroxide widely used as initiator of free radical production in several biological systems. However, the prooxidant capacity of this compound remins unclear.

Cholesterol and 25-hydroxycholesterol retention in specimens of liver and aorta prepared for electron microscopy. II. Effect of filipin, osmium, digitonin and saponin.

Sprague-Dawley rats were injected intraperitoneally with [1 alpha, 2 alpha(n)-3H]cholesterol or 25-hydroxy-[26,27-3H]cholesterol, and one and five days later liver and aortic tissues were fixed. The extent to which these sterols were lost from the tissues during preparation for electron microscopy (EM) was examined utilizing different fixation procedures and various protective agents. Radioactive tracers, scintillation counting and standard EM techniques were used.

Cholesterol and 25-hydroxycholesterol retention in specimens of liver and aorta prepared for electron microscopy. I. Standard fixation methods and metabolism of the labeled sterols.

In the present work, several preparatory procedures commonly used for electron microscopy (EM) were evaluated as to their ability to preserve cholesterol (CHO) and CHO derivatives in tissue. We also determined in several rat tissues to what extent the sterols used as tracers are metabolized. Sprague-Dawley rats were injected intraperitoneally with [1 alpha,2 alpha(n)-3H]cholesterol ([3H]CHO) and 25-hydroxy-[26,27-3H]cholesterol ([3H]25-OH-CHO).

Effect of cholesterol and its autooxidation derivatives on endocytosis and dipeptidyl peptidases of aortic endothelial cells.

The effects of cholesterol (CHO) and cholesterol autooxidation derivatives (CAD) on the endocytosis of cationized ferritin (CF) by endothelial cells have been investigated. The effect of both substances on the activity of lysosomal enzymes dipeptidyl peptidase I (DPP I) and dipeptidyl peptidase II (DPP II) was also studied. Treatment of rats with CAD induced striking alterations in the ultrastructure of endothelial cells and makes it impossible to analyze the effect of this toxin on endocytosis processes.

Hyperreactivity and 45Ca movements in sensitized guinea-pig tracheal muscle.

Responses to KCl and histamine and 45Ca movements were studied in trachea from normal and actively sensitized guinea-pigs. Sensitized tracheas were hyperresponsive and hypersensitive to KCl and histamine. 45Ca uptake experiments show that sensitized tracheal muscle behaves as normal except that the uptake of 45Ca in low concentration (0.

Relationship between nonspecific airway hyperreactivity and antigen-induced contraction in an allergic animal model in vitro.

Tracheal strips from actively sensitized guinea pigs exhibited an enhanced responsiveness (greater maximal effects; Emax) and sensitivity (smaller effective concentration 50%; pD2) to CaCl2 (in K(+)-depolarized tissues), KCl and histamine compared with that of strips from nonsensitized animals. A significant correlation was found between the magnitude of the contraction produced by bovine serum albumin (1 mg/ml) and the Emax and pD2 values of CaCl2, KCl and histamine in tracheal strips from sensitized guinea pigs. This indicates that specific and nonspecific challenges correlate in sensitized guinea pig trachea.

Sources of calcium for the contraction induced by various agonists in trachealis muscle from normal and sensitized guinea pigs.

Active sensitization of guinea pigs resulted in an increase in the responsiveness and sensitivity of tracheal strips to CaCl2 in K+-depolarized tissue (Emax 0.81 +/- 0.22 g/mm2 and pD2 2.

Autoradiography of endothelium in whole rat aorta by a new method.

This report describes a method for studying the arterial endothelial kinetics in the rat by autoradiography of the luminal surface of the endothelium. The procedure involves stripping off the adventitia, sticking the 'whole' artery on a glass slide, and covering the endothelium (with some layers of the media as a support) with the nuclear emulsion. This method gives endothelial autoradiographies with very good optical quality, so that counting the labelled cells is as easy as in the Häutchen preparations.

Cholesterol oxygenated derivatives induce erythrocyte accumulation and endothelium alterations in the aorta of rats. Turnover of endothelial cells in the apparently intact areas remains unchanged.

In this work we have studied the effect of cholesterol autooxidation derivatives on the aortic endothelium of rat. Endothelial alterations were evident after 24 h treatment. Areas showing many spindle shaped nuclei and focal accumulation of erythrocytes were observed.

Prostacyclin production and lipid peroxidation in the aorta of rats fed with cholesterol autoxidation products.

The stable metabolite of prostacyclin 6-keto PGF1 alpha originating from the (1-14C) arachidonic acid, and lipid peroxidation expressed as thiobarbituric acid-reacting substance (TBARS) were studied in the aorta of rats fed a diet enriched in 2% w/w cholesterol autoxidation products for 24 hours prior to sacrifice. A slight increase was found in the amount of TBARS as well as in the conversion of (1-14C) arachidonic acid to 6-keto PGF1 alpha. These results suggest that in aorta there exists a protection mechanism which acts to increase the production of prostacyclin.

Dysfunctional plasminogen in full term newborn--study of active site of plasmin.

The functional activity and active site of plasmin in full-term newborns have been studied and compared to those in adults in order to investigate the nature of the abnormality found in newborn plasminogen described in a previous paper. The functional activity of newborn plasminogen measured on chromogenic substrate was approximately 18% that of adult plasminogen when streptokinase was used as an activator and 12% when urokinase was used. Proteolysis of newborn plasminogen by urokinase yielding a two-chain plasmin form occurred normally, but the incorporation of diisopropylphosphorofluoridate into the light chain of newborn plasmin was approximately 23% of that observed in the light chain of adult plasmin.