Estudio preliminar sobre algunas rocas volcánicas y volcano-sedimentarias de la provincia de Huelva

Se ha realizado una primera clasificación de algunas rocas volcánicas del Norte de la provincia de Huelva, con base geoquímica. De acuerdo con ésta, se apuntan algunas posibilidades genéticas

Textural and geochemical features of pyrite from the intramagmatic Ni-Cu-PGE mineralization of Aguablanca (Badajoz)

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasFALSEEspaña. Dirección General de Investigación Científica y Técnicapu

Recobriments antiadherents sobre titani: mètodes de deposició de poli(etilenglicol)

Els implants dentals són àmpliament utilitzats per a la substitució de peces dentals perdudes. Tot i la seva elevada taxa d’èxit, es produeixen fallades en un 5-10% dels implants col•locats. Per evitar les fallades per infecció cal evitar l’adhesió bacteriana inicial, fita que es pot assolir amb els recobriments antiadherents. En aquest estudi es realitza la comparativa de tres mètodes diferents per l’obtenció de recobriments de poli(etilenglicol) (PEG) sobre titani per aplicacions en implants dentals. Els mètodes estudiats han estat la polimerització per plasma, l’electrodeposició i la silanització. Els tres mètodes permeten obtenir un recobriment de PEG a la superfície del titani, amb composició química semblant i una reducció de l’adhesió bacteriana. L’adhesió cel•lular no es veu significativament afectada en cap dels casos.Peer Reviewe

DNA polymerase λ, a novel DNA repair enzyme in human cells

DNA polymerase lambda (pol λ) is a novel family X DNA polymerase that has been suggested to play a role in meiotic recombination and DNA repair. The recent demonstration of an intrinsic 5′-deoxyribose-5-phosphate lyase activity in pol λ supports a function of this enzyme in base excision repair. However, the biochemical properties of the polymerization activity of this enzyme are still largely unknown. We have cloned and purified human pol λ to homogeneity in a soluble and active form, and we present here a biochemical description of its polymerization features. In support of a role in DNA repair, pol λ inserts nucleotides in a DNA template-dependent manner and is processive in small gaps containing a 5′-phosphate group. These properties, together with its nucleotide insertion fidelity parameters and lack of proofreading activity, indicate that pol λ is a novel β-like DNA polymerase. However, the high affinity of pol λ for dNTPs (37-fold over pol β) is consistent with its possible involvement in DNA transactions occurring under low cellular levels of dNTPs. This suggests that, despite their similarities, pol β and pol λ have nonredundant in vivo functions.This work was supported by Ministerio de Ciencia y Tecnologı´a Grant BMC2000-1138, Comunidad Auto´noma de Madrid Grant 08.5/0063/2000 (to L. B.) and by an institutional grant from Fundacio´n Ramo´n Areces

Comparative evaluation of the effects of short-term inhalation exposure to diesel engine exhaust on rat lung and brain

Combustion-derived nanoparticles, such as diesel engine exhaust particles, have been implicated in the adverse health effects of particulate air pollution. Recent studies suggest that inhaled nanoparticles may also reach and/or affect the brain. The aim of our study was to comparatively evaluate the effects of short-term diesel engine exhaust (DEE) inhalation exposure on rat brain and lung. After 4 or 18 h recovery from a 2 h nose-only exposure to DEE (1.9 mg/m(3)), the mRNA expressions of heme oxygenase-1 (HO-1), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and cytochrome P450 1A1 (CYP1A1) were investigated in lung as well as in pituitary gland, hypothalamus, olfactory bulb, olfactory tubercles, cerebral cortex, and cerebellum. HO-1 protein expression in brain was investigated by immunohistochemistry and ELISA. In the lung, 4 h post-exposure, CYP1A1 and iNOS mRNA levels were increased, while 18 h post-exposure HO-1 was increased. In the pituitary at 4 h post-exposure, both CYP1A1 and HO-1 were increased; HO-1 was also elevated in the olfactory tuberculum at this time point. At 18 h post-exposure, increased expression of HO-1 and COX-2 was observed in cerebral cortex and cerebellum, respectively. Induction of HO-1 protein was not observed after DEE exposure. Bronchoalveolar lavage analysis of inflammatory cell influx, TNF-α, and IL-6 indicated that the mRNA expression changes occurred in the absence of lung inflammation. Our study shows that a single, short-term inhalation exposure to DEE triggers region-specific gene expression changes in rat brain to an extent comparable to those observed in the lung

Differential genomic targeting of the transcription factor TAL1 in alternate haematopoietic lineages

Expression of the basic helix-loop-helix transcription factor TAL1/SCL is required for erythrocyte differentiation; aberrant expression in lymphoid cells leads to oncogenic transformation. Here, global analysis of TAL1 binding in erythroid and malignant T cells identifies cell type specific functional interaction with the transcription factors RUNX and ETS1