Search Results - (Author, Cooperation:J. Botas)

2013-05-31

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Amino Acid Sequence ; Animals ; Animals, Genetically Modified ; Ataxin-1 ; Ataxins ; Cell Line, Tumor ; Disease Models, Animal ; Down-Regulation/drug effects ; Drosophila melanogaster/genetics/*metabolism ; Female ; Humans ; MAP Kinase Signaling System/drug effects ; Male ; Mice ; Mitogen-Activated Protein Kinases/*metabolism ; Molecular Sequence Data ; Molecular Targeted Therapy ; Nerve Tissue Proteins/chemistry/genetics/*metabolism/*toxicity ; Nuclear Proteins/chemistry/genetics/*metabolism/*toxicity ; Phosphorylation ; Protein Stability/drug effects ; Ribosomal Protein S6 Kinases, 90-kDa/deficiency/genetics/*metabolism ; Spinocerebellar Ataxias/*metabolism/*pathology ; Transgenes ; ras Proteins/*metabolism

0955-0674

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Medicine

Electronic Resource

1435-1803

oxygen free radicals ; reperfusionarrhythmias ; infarct size ; superoxide dismutase

Springer Online Journal Archives 1860-2000

Medicine

Summary The effects of an intracoronary infusion of superoxide dismutase on infarct size were studied in 16 pigs submitted to a 48-min coronary occlusion of the mid left anterior descending coronary artery followed by reperfusion for 24 h. Areas at risk marked with fluoresccine and infarct sizes calculated with triphenyl tetrazolium chloride staining 24 h after the occlusion were similar in the five control animals with coronary reperfusion alone, in the five animals with an intracoronary infusion of lactate Ringer initiated 3 min before reperfusion and maintained for 33 min and in the six animals with superoxide dismutase added to the solution of lactate Ringer and infused at a rate of 2500 units/min. The ratios infarct size/area at risk were respectively 0.50±0.10, 0.63±0.10 and 0.65±0.04 in the three study groups (NS). The extent of intramyocardial hemorrhage, evaluated by morphometric analysis was also similar 0.90±0.29×106, 0.70±0.14 and 1.62±0.42 red blood cells/mm3 of tissue (NS). The superoxide dismutase infusion, however, resulted in significantly fewer early reperfusion arrhythmias which involved 23±15 s of each minute electrocardiographic recording in the superoxide dismutase group, compared to 37±13 s in the lactate Ringer group and 45±14 s in the control group (p=0.004). The lack of an effect of intracoronary infusion of superoxide dismutase on infarct size suggests that in this experimental model, extracellular superoxide radicals generated during early reperfusion have no major role on myocardial cell necrosis and microvascular damage. Reperfusion arrhythmias were, however, reduced.

Electronic Resource

1432-041X

Gene regulation ; Developmental pathways ; Antennapedia and Bithorax complexes in Drosophila

Springer Online Journal Archives 1860-2000

Biology

Summary We have studied the embryonic and adult phenotypes of genetic combinations between Polycomb (Pc), Regulator of bithorax (Rg-bx) and the genes of the Bithorax complex (BX-C) and the Antennapedia complex (ANT-C). The products of Pc and Rg-bx genes act antagonistically, their mutant combinations leading to the ectopic expression of genes of the BX-C and ANT-C. The genetic analysis of the Pc locus suggests it is a complex gene. Pc+ products behave as members of a “regulatory set” that negatively control the expression of BX-C and ANT-C genes. Genetic combinations between different doses of Pc, Rg-bx and the genes of the BX-C and ANT-C have phenotypes which may be interpreted as resulting from ectopic derepression of posterior selector genes repressing selector genes of anterior segments. The transformation phenotypes of certain genetic combinations differ in embryos and adults. A model of regulation of the BX-C and the ANT-C genes during the imaginal cell proliferation is presented, in which the specification state is maintained by self-activation of a given selector gene and down modulation of other selector genes in the same cell.

Electronic Resource

1432-1793

Springer Online Journal Archives 1860-2000

Biology

Abstract The storage of nitrate by phytoplankton cells during the early phases of upwelling was studied in coastal stations off northern Spain (southern Bay of Biscay) between 1990 and 1994. In this region, a persistent upwelling during summer is characterised by intermittent pulses of variable intensity, and increased nutrient concentrations in the surface layer. The main effect of an upwelling pulse on phytoplankton distribution is the shifting of the chlorophyll a and primary production maxima to near the surface. When the upwelling relaxes, thermal stratification of the water column occurs, and a distinct subsurface chlorophyll maximum develops below the production maximum. An accumulation of intracellular nitrate characterized the early phases of upwelling (mean = 2.73 μmol N m−3), maximum concentrations being attained at depths where biomass and production values were moderate. In contrast, phytoplankton cells from non-upwelling situations contained significantly lower concentrations of intracellular nitrate (mean = 0.17 μmol N m−3). The variations in the intracellular pool of nitrate may result from the differential allocation of resources within the cell as a result of variations in the energy available, since the uptake and assimilation of nitrate is a relatively expensive process involving several enzymatic systems. We hypothesize that nitrate storage by phytoplankton cells is characteristic of early phases of upwelling and is linked to patterns of carbon fixation. Average nitrogen budgets for upwelling and non-upwelling situations indicate that intracellular nitrate reserves are not responsible for maintaining high phytoplankton growth rates, since they only account for 〈2% of daily primary production during upwelling events.

Electronic Resource

1573-4803

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract The synthesis of cordierite monolithic honeycombs by solid state reaction at high temperature of alumina, kaolin, talc and silica has been studied. The synthesized honeycombs have been characterized by DTA and XRD. The crystal composition of the samples have been observed to be very dependent on temperature and time of reaction. Thermal treatment of the monolithic precursors at 1400°C for 30 minutes allows formation of high purity cordierite with high crystallinity, maintaining the desired monolithic structure of the honeycombs.

Electronic Resource