Browsing by Author "Lagos, N"

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    Lung oxidative stress as related to exercise and altitude.: Lipid peroxidation evidence in exhaled breath condensate
    (2005) Araneda, OF; García, C; Lagos, N; Quiroga, G; Cajigal, J; Salazar, MP; Behn, C
    Lung oxidative stress (OS) was explored in resting and in exercising subjects exposed to moderate and high altitude. Exhaled breath condensate (EBC) was collected under field conditions in male high-competition mountain bikers performing a maximal cycloergometric exercise at 670 m and at 2,160 m, as well as, in male soldiers climbing up to 6,125 m in Northern Chile. Malondialdehyde concentration [MDA] was measured by high-performance liquid chromatography in EBC and in serum samples. Hydrogen peroxide concentration [H2O2] was analysed in EBC according to the spectrophotometric FOX2 assay. [MDA] in EBC of bikers did not change while exercising at 670 m, but increased from 30.0 +/- 8.0 to 50.0 +/- 11.0 nmol l(-1) (P < 0.05) at 2,160 m. Concomitantly, [MDA] in serum and [H2O2] in EBC remained constant. On the other hand, in mountaineering soldiers, [H2O2] in EBC under resting conditions increased from 0.30 +/- 0.12 mu mol l(-1) stop at 670 m to 1.14 +/- 0.29 mu mol l(-1) stop immediately on return from the mountain. Three days later, [H2O2] in EBC (0.93 +/- 0.23 mu mol l(-1) stop) continued to be elevated (P < 0.05). [MDA] in EBC increased from 71 +/- 16 nmol l(-1) stop at 670 m to 128 +/- 26 nmol l(-1) stop at 3,000 m (P < 0.05). Changes of [H2O2] in EBC while ascending from 670 m up to 3,000 m inversely correlated with concomitant variations in HbO2 saturation (r=-0.48, P < 0.05). AMS score evaluated at 5,000 m directly correlated with changes of [MDA] in EBC occurring while the subjects moved from 670 to 3,000 m (r=0.51, P < 0.05). Lung OS may constitute a pathogenic factor in AMS.
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    Two oceans, two taxa and one mode of development
    (2003) Astorga, A; Fernández, M; Boschi, EE; Lagos, N
    The latitudinal gradient of species diversity is a widely recognized but poorly understood phenomenon. In marine systems, differences in dispersal abilities among species may pose an additional problem in identifying the processes that affect diversity. We compared latitudinal diversity gradients along two parallel continental coasts, the east and west coasts of South America, of two groups of Crustacea (Brachyura and Anomura), which exclusively exhibit planktonic development. We also evaluated the species-area and the energy-input hypotheses. Diversity decreased with increasing latitude for both groups in both oceans. Results suggest that the spatial structure of sea surface temperature (SST) explains diversity of both groups at large, but not small (<5 degrees), scales. Range size and latitude were not correlated. We hypothesize that SST differentially affects taxa with contrasting modes of development, influencing patterns of diversity. We suggest that developmental modes of marine organisms should be considered in future diversity analyses.