[en] Oxytocin a cyclic peptide whose sequence CYIQNCPLG was the first biologically relevant peptide to be synthesized. Synthesis by Boc strategy using p-methyl benzhydrylamine resin and also by Fmoc using Rink p-methyl benzhydrylamine resin was carried out with high yields. The crude peptide was cycled with 10% dimethylsulfoxide, characterized by mass spectrometry and nuclear magnetic resonance showing the presence of two isomers

[en] The main maintenance objective is to assure that the safety features of structures, components and systems of nuclear power plants are kept as designed. Therefore, there is a direct relationship between safety and maintenance. Owing to the above mentioned, maintenance activities are considered a relevant regulatory issue for the Argentine Nuclear Regulatory Authority (ARN). This paper describes the regulatory control to maintenance activities of Argentine nuclear power plants. It also addresses essential elements for maintenance control, routine inspections, special inspections during planned outages, audits and license conditions and requirements. (author)

[en] A convenient approach for synthesis of dendrimetric peptides is proposed. The strategy was developed by using unprotected dimeric peptides as building blocks. Our model involved the direct synthesis of a Cysteine containing dimer peptide and subsequent sulfhydryl group oxidation. The disulfide bridge formation reaction to get 90 amino acid residues tetrameric molecule is performed with dimethyl sulfoxide. This kind of dendrimetric peptide synthesis is called Double Dimer Construction System, and could be applied to obtain synthetic vaccines

[en] A graphical method is described that allows the determination of specific radioactivities of radioactively labelled hormones. This method combines the self-displacement technique, plotting bound/free ratios versus mass of unlabelled hormone or total radioactivity of labelled preparation added to the receptor preparation, and the maximal binding capacity of the labelled hormone. The procedure presented provides a more realistic specific radioactivity for use in all binding experiments. Application of the method is demonstrated for ¹²⁵I-labelled ovine prolactin, and data are presented for ¹²⁵I-labelled human choriogonadotropin and [³H]testosterone. (author)

[en] The proteoglycans (cell-associated and culture media) in 3T3-L1 preadipocytes in culture were analyzed before and during differentiation into adipocytes. Cells were metabolically labeled with [35S]sulfate and [3H] glucosamine for 24 h and then extracted and analyzed. There was a 1.68 ± 0.07-fold increase in the 35S in medium proteoglycan during differentiation, whereas cell-associated proteoglycan radioactivity showed no increase. Analyses of radiolabeled molecules using ion-exchange chromatography, gel filtration, and high performance liquid chromatography after enzymatic or alkaline digestion indicated that all of the 35S label was recovered as two major species of chondroitin 4-sulfate proteoglycans (CSPG-I and CSPG-II) and 7% as heparan sulfate proteoglycan. CSPG-I has a mass of ∼ 970 kDa with multiple chondroitin sulfate chains (average of 50 kDa each) and a core protein of ∼ 370 kDa including oligosaccharides. CSPG-II has a mass of 140 kDa with one or two chondroitin sulfate chains (average of 68 kDa each) and a core protein of 41 kDa including oligosaccharides. CSPG-I appears to be similar to versican, whereas CSPG-II is similar to decorin and/or biglycan, found in other fibroblastic cells. Cell differentiation was associated with a specific increase in CSPG-I (4.0 ± 0.2-fold in media and 3.2 ± 0.5-fold in the cell-associated form). This system should facilitate study of the functional roles of proteoglycans during growth and differentiation