Probucol prevents oxidative injury to endothelial cells

We evaluated the effect of the antioxidant, probucol, on the cytotoxic effects of oxidized low density lipoprotein (OX-LDL) or of cumene hydroperoxide (CumOOH) on cultured bovine endothelial cells (EC). The addition of CumOOH to EC caused the release of lactate dehydrogenase and the accumulation of thiobarbituric acid-reacting substances (TBARS), effects that were protected against by preincubation with either probucol or tocopherol. Similarly, preincubation of EC with those antioxidants protected against OX-LDL toxicity and the accumulation of TBARS. The content of probucol in EC measured by high performance liquid chromatography was directly correlated with the extent of protection against OX-LDL toxicity. We also found that treatment of EC with serum from patients receiving treatment with probucol resulted in the detection of probucol in the cells. We conclude that probucol is transported and incorporated into EC membranes to act as a radical-trapping antioxidant, protecting the EC against oxidative stress. Our results also indicate that lipid peroxidation in cellular membranes involves cell injury inflicted by OX-LDL.     

IR-Met and IR-leu-enkephalin content in the perioesophageal ganglia of Helix aspersa seasonal variations.

1. In order to determine the presence of opioid peptides and their possible variation throughout the year in the different ganglia of the perioesophageal ring of the terrestrial snail Helix aspersa, radioimmunoassays with highly specific antisera risen for Met-enkephalin (ME) and Leu-enkephalin (LE) were carried out monthly. 2. Clear monthly variation in both IR-enkephalins' concentrations were found, following a seasonal trend. IR-LE concentrations were higher than IR-ME throughout the year in all the regions, however, no clear regional differences were found for each. 3. IR-LE/IR-ME ratios presented defined seasonal peaks for each region.     

Molecular cloning, genetic mapping, and expression of the mouse Sf3b1 (SAP155) gene for the U2 snRNP component of spliceosome

SAP155, a subunit of the U2 snRNP, is essential for prespliceosome assembly and splicing catalysis of the major spliceosome. Moreover, the protein has been identified in the minor (U12-dependent) spliceosome. These facts strongly suggest that SAP155 is shared by two distinct complexes owing to its importance in the removal of any type of intron. Here we have isolated a cDNA encoding the 146-kDa mouse homolog, designated Sf3b1. The amino acid sequence of Sf3b1 is very highly conserved among homologs from Schizosaccharomyces pombe (52.4% identity) to human (99.6%), and the C-terminal 825 residues of these Sf3b1 homologs show even higher identities. This C-terminal region shows significant similarity to the PR65 subunit of protein phosphatase 2A, which is composed of 15 tandem repeats of a 39 amino acid sequence. Mouse genome analyses showed Sf3b1 to be a single-copy gene mapping to the central part of Chromosome (Chr) 1. Northern blot analysis and whole mount in situ hybridization revealed Sf3b1 to be ubiquitously expressed in a variety of adult tissues and mid-gestation embryos. Received: 14 June 2000 / Accepted: 19 October 2000