Streamflow variations across the Andes (18°-55°S) during the instrumental era.

The rivers originating in the southern Andes (18°-55°S) support numerous ecosystems and a large number of human populations and socio-economic activities in the adjacent lowlands of Chile, Argentina and Bolivia. Here we show that ca. 75% of the total variance in the streamflow records from this extensive region can be explained by only eight spatially coherent patterns of variability. Five (three) of these Andean patterns exhibit extreme dry (wet) conditions in recent years, with strong interannual variations in northern Chile; long-term drying trends between 31° and 41°S; a transitional pattern in the central Patagonian Andes; and increasing trends in northwestern Argentina and southern Bolivia, the Fueguian Andes, and the eastern portion of the South Patagonian Icefield. Multivariate regression analyses show that large-scale indices of ENSO variability can predict 20% to 45% of annual runoff variability between 28° and 46°S. The influence of Antarctic and North Pacific indices becomes more relevant south of 43°S and in northwestern Argentina and southern Bolivia, respectively, but their overall skill as predictors of Andean streamflows is weak. The analyses provide relevant new information to improve understanding of the spatial coherence, the main temporal features, and the ocean-atmospheric forcings of surface runoff across the southern Andes.

The host tissue reaction to Madurella mycetomatis: new classification.

In this prospective study, three types of tissue reaction to mycetoma grains are described. Type I reaction is characterized by the adherence of neutrophils to the surface of the grain leading to its disintegration. In Type II reaction, the fragmented grain and the dead neutrophils are cleared by macrophages and multinucleated giant cells, while in Type III reaction there is a discrete well developed epithelioid granuloma with Langhans's giant cells. The three types of reaction are usually seen in different combinations in the same lesion.

A preliminary study on the ultrastructure of Actinomadura pelletieri and its host tissue reaction.

This is the first report on the fine structure of Actinomadura pelletieri. The in vitro ultrastructure of the organism and that of the grain in vivo were similar. The grain consisted of packed filaments with a faintly electron-dense matrix in between. The individual filament was septate, the cytoplasm was either vacuolated or contained intracellular organelles and the cytoplasmic membrane was adherent to the filamentous wall, which has three electron-dense and two electron-lucent layers. The absence of cement substance around the grain may partially explain the aggressive and destructive behaviour of this organism and may probably also explain its good response to medical treatment. The inflammatory host reaction was similar to that seen with all mycetoma organisms except that there was a massive neutrophil reaction. This was confirmed by electron microscopy.