RESUMO
Migratory behaviour of selected fish species is described in the Paraná River, Brazil-Argentina-Paraguay, to search for patterns relevant to tropical regulated river systems. In a 10 year mark-recapture study, spanning a 1425 km section of the river, 32 867 fishes composed of 18 species were released and 1083 fishes were recaptured. The fishes recaptured were at liberty an average 166 days (maximum 1548 days) and travelled an average 35 km (range 0-625 km). Cluster analysis applied to variables descriptive of movement behaviour identified four general movement patterns. Cluster 1 included species that moved long distances (mean 164 km) upstream (54%) and downstream (40%) the mainstem river and showed high incidence (27%) of passage through dams; cluster 2 also exhibited high rate of movement along the mainstem (49% upstream, 13% downstream), but moved small distances (mean 10 km); cluster 3 included the most fishes moving laterally into tributaries (45%) or not moving at all (25%), but little downstream movement (8%); fishes in cluster 4 exhibited little upstream movement (13%) and farthest downstream movements (mean 41 km). Whereas species could be numerically clustered with statistical models, a species ordination showed ample spread, suggesting that species exhibit diverse movement patterns that cannot be easily classified into just a few classes. The cluster and ordination procedures also showed that adults and juveniles of the same species exhibit similar movement patterns. Conventional concepts about Neotropical migratory fishes portray them as travelling long distances upstream. The present results broaden these concepts suggesting that migratory movements are more diverse, could be long, short or at times absent, upriver, downriver or lateral, and the diversity of movements can vary within and among species. The intense lateral migrations exhibited by a diversity of species, especially to and from large tributaries (above reservoirs) and reservoir tributaries, illustrate the importance of these habitats for the fish species life cycle. Considering that the Paraná River is highly impounded, special attention should be given to the few remaining low-impact habitats as they continue to be targets of hydropower development that will probably intensify the effects on migratory fish stocks.
Assuntos
Migração Animal , Peixes/fisiologia , Rios , Sistemas de Identificação Animal , Animais , Argentina , Brasil , Ecossistema , Modelos Estatísticos , ParaguaiRESUMO
Glial cells prevail in number and in diversity of cellular phenotypes in the nervous system. They have also gained prominence due to their multiple physiological and pathophysiological roles. Our current knowledge of the asymmetry and heterogeneity of the plasma membrane demands an in depth analysis of the diverse array of membrane microdomains postulated to exist in the context of glial cells. This review focuses and analyzes the studies reported to date on the detection of caveolae membrane rafts and the caveolin family members in glial cell model systems, the conditions leading to changes in their level of expression, and their functional and clinical significance. Outstanding in this work emerge the ubiquitous expression of caveolins, including the typically regarded 'muscle-specific' cav3, in diverse glial cell model systems, their participation in reactive astrogliosis, cancer, and their key relevance to calcium signaling. The knowledge obtained to date demands incorporation of the caveolins and caveolae membrane rafts in our current models on the role of glial cells in heath and neurological disease.
Assuntos
Caveolinas/metabolismo , Membrana Celular/metabolismo , Neuroglia/citologia , Transdução de Sinais/fisiologia , Animais , Cálcio/metabolismo , Modelos BiológicosRESUMO
Se informa la observacion de un caso de sindrome de Larsen, siendo el segundo caso de la literatura nacional. Este cuadro fue descripto por primera vez por Larsen y col en 1950. Es de rara observacion y han sido descriptos una treintena de casos en la literatura mundial. Esta cantidad no se menciona en los tratados de Pediatria, Ortopedia y Radiologia, siendo posible su publicacion con otras denominaciones. El recien nacido presenta luxaciones multiples de las grandes articulaciones: codos, caderas y rodillas, que se acompanan de malformaciones mediofaciales: paladar ojival, nariz achatada y depresible, frente prominente o hipertelorismo ocular. Se estudia la historia natural de la enfermedad describiendose mejoria articular sin recuperacion total y cociente intelectual normal. El estudio radiologico revela gran compromiso articular. El patron de herencia es discutido y se realizan consideraciones etiopatogenicas. Nuestro caso se interpreta como un mutacion "de novo"
Assuntos
Humanos , Feminino , Anormalidades Múltiplas , Expressão Facial , Luxações Articulares , Pé TortoRESUMO
Se informa la observacion de un caso de sindrome de Larsen, siendo el segundo caso de la literatura nacional. Este cuadro fue descripto por primera vez por Larsen y col en 1950. Es de rara observacion y han sido descriptos una treintena de casos en la literatura mundial. Esta cantidad no se menciona en los tratados de Pediatria, Ortopedia y Radiologia, siendo posible su publicacion con otras denominaciones. El recien nacido presenta luxaciones multiples de las grandes articulaciones: codos, caderas y rodillas, que se acompanan de malformaciones mediofaciales: paladar ojival, nariz achatada y depresible, frente prominente o hipertelorismo ocular. Se estudia la historia natural de la enfermedad describiendose mejoria articular sin recuperacion total y cociente intelectual normal. El estudio radiologico revela gran compromiso articular. El patron de herencia es discutido y se realizan consideraciones etiopatogenicas. Nuestro caso se interpreta como un mutacion "de novo"