Generation of CD4(+)CD45RA(+) effector T cells by stimulation in the presence of cyclic adenosine 5'-monophosphate-elevating agents

After TCR cross-linking, naive CD4(+)CD45RA(+) T cells switch to the expression of the CD45RO isoform and acquire effector functions. In this study we have shown that cAMP-elevating agents added to anti-CD3- and anti-CD28-stimulated cultures of T lymphocytes prevent acquisition of the CD45RO(+) phenotype and lead to the generation of a new subpopulation of primed CD4(+)CD45RA(+) effector cells (cAMP-primed CD45RA). These cells displayed a low apoptotic index, as the presence of dibutyryl cAMP (dbcAMP)-rescued cells from CD3/CD28 induced apoptosis. Inhibition of CD45 splicing by dbcAMP was not reverted by addition of exogenous IL-2. cAMP-primed CD45RA cells had a phenotype characteristic of memory/effector T lymphocytes, as they showed an up-regulated expression of CD2, CD44, and CD11a molecules, while the levels of CD62L Ag were down-regulated. These cells also expressed the activation markers CD30, CD71, and HLA class II Ags at an even higher level than CD3/CD28-stimulated cells in the absence of dbcAMP. In agreement with this finding, cAMP-primed CD45RA cells were very efficient in triggering allogenic responses in a MLR. In addition, cAMP-primed CD45RA cells produce considerable amounts of the Th2 cytokines, IL-4, IL-10, and IL-13, whereas the production of IFN-gamma and TNF-alpha was nearly undetectable. The elevated production of IL-13 by neonatal and adult cAMP-primed CD45RA cells was specially noticeable. The cAMP-dependent inhibition of CD45 splicing was not caused by the production of immunosuppressor cytokines. These results suggest that within the pool of CD4(+)CD45RA(+) cells there is a subpopulation of effector lymphocytes generated by activation in the presence of cAMP-elevating agents.     

2-styrylchromones as novel inhibitors of xanthine oxidase. A structure-activity study

The purpose of this study was the evaluation of the xanthine oxidase (XO) inhibition produced by some synthetic 2-styrylchromones. Ten polyhydroxylated derivatives with several substitution patterns were synthesised, and these and a positive control, allopurinol, were tested for their effects on XO activity by measuring the formation of uric acid from xanthine. The synthesised 2-styrylchromones inhibited xanthine oxidase in a concentration-dependent and non-competitive manner. Some IC50 values found were as low as 0.55 microM, which, by comparison with the IC50 found for allopurinol (5.43 microM), indicates promising new inhibitors. Those 2-styrylchromones found to be potent XO inhibitors should be further evaluated as potential agents for the treatment of pathologies related to the enzyme's activity, as is the case of gout, ischaemia/reperfusion damage, hypertension, hepatitis and cancer.     

<Emphasis Type="Italic">Rhizopus microsporus</Emphasis> var.<Emphasis Type="Italic"> rhizopodiformis</Emphasis>: a thermotolerant fungus with potential for production of thermostable amylases

The effect of several nutritional and environmental parameters on growth and amylase production from Rhizopus microsporus var. rhizopodiformis was analysed. This fungus was isolated from soil of the Brazilian "cerrado" and produced high levels of amylolytic activity at 45°C in liquid medium supplemented with starch, sugar cane bagasse, oat meal or cassava flour. Glucose in the culture medium drastically repressed the amylolytic activity. The products of hydrolysis were analysed by thin layer chromatography, and glucose was detected as the main component. The amylolytic activity hydrolysed several substrates, such as amylopectin, amylase, glycogen, pullulan, starch, and maltose. Glucose was always the main end product detected by high-pressure liquid chromatography analysis. These results indicated that the amylolytic activity studied is a glucoamylase, but there were also low levels of -amylase. As compared to other fungi, R. microsporus var. rhizopodiformis can be considered an efficient producer of thermostable amylases, using raw residues of low cost as substrates. This information is of technological value, considering the importance of amylases for industrial hydrolysis.     

The Tissue Bank at the National Nuclear Research Institute in Mexico

The Instituto Nacional de Investigaciones Nucleares (ININ, The National Nuclear Research Institute) received during 1997-1998 strong support of the International Atomic Energy Agency (IAEA), to establish the first and only one tissue bank (BTR ININ tissue bank) in Mexico that uses ionising radiation as sterilising agent. In that time, the BTR staff was trained in different tissue banks in several countries. Basic equipment for tissue processing donated by the IAEA was received in 1998. In July, 1999 the Mexican Health Secretariat gave the Sanitary License No. 1062000001 to the BTR to operate as an official organ and tissue bank. In August, 2001 the ININ and the Hospital Materno Infantil (HMI-ISSEMYM) signed an agreement to collaborate in amnion processing. The hospital is responsible for donor selection, serology tests, tissue procurement and washing, since this hospital is the BTR amnion supplier. The tissues are collected by ININ weekly with complete documentation. The BTR is responsible for processing: cleaning, air drying, packaging, labelling, microbiological control and sterilisation by gamma irradiation. The sterilised tissue is kept under quarantine for 6 months to obtain the results of the donor second serology test. From March to June, 2002 the BTR has processed 347.86 units (50 cm(2) each), is say, 17,393 cm(2). In addition, the pig skin xenograft process has been implemented and a protocol for clinical applications of it is running at the Hospital Central Sur de Alta Especialidad (PEMEX). Also the ININ tissue bank present status and perspectives are described.     

Recognition of Carbohydrate Epitopes Specific for Electron-Dense Granule Antigens from Entamoeba histolytica by Monoclonal Antibodies in the Cecal Content of Infected Hamsters

Saccharomyces cerevisiae CGR1 encodes a 120-amino acid protein with a predominant nucleolar localization. In this study we report the identification and cloning of the ortholog, cgrA, from Aspergillus nidulans. The cgrA gene is comprised of three exons on A. nidulans Chromosome 7. The cDNA contains a single open reading frame (ORF) that would encode a protein of 114 amino acids with 44% sequence identity to yeast Cgr1p. A plasmid expressing cgrA complemented the impaired growth phenotype of a yeast strain that can be inducibly depleted of CGR1, and a green fluorescent protein (GFP)-tagged CgrA protein had the same nucleolar localization as the corresponding yeast protein. These results identify cgrA as the A. nidulans ortholog of yeast CGR1 and suggest evolutionary conservation of nucleolar localization mechanisms used by these proteins. Received: 14 September 2000 / Accepted: 13 November 2000     

Design,synthesis, and docking of highly hypolipidemic agents: Schizosaccharomyces pombe as a new model for evaluating α-asarone-based HMG-CoA reductase inhibitors

A series of α-asarone-based analogues was designed by conducting docking experiments with published crystal structures of human HMG-CoA reductase. Indeed, synthesis and evaluation of this series showed a highly hypocholesterolemic in vivo activity in a murine model, as predicted by previous docking studies. In agreement with this model, the polar groups attached to the benzene ring could play a key role in the enzyme binding and probably also in its biological activity, mimicking the HMG-moiety of the natural substrate. The hypolipidemic action mechanism of these compounds was investigated by developing a simple, efficient, and novel model for determining HMG-CoA reductase inhibition. The partial purification of the enzyme from Schizosaccharomyces pombe allowed for testing of α-asarone- and fibrate-based analogues, resulting in positive and significant inhibitory activity.