ABSTRACT
Water quality is essential for successful aquaculture. For freshwater shrimp farming, ammonia concentrations can increase considerably, even when culture water is renewed frequently, consequently increasing the risk of ammonia intoxication. We investigated ammonia lethality (LC50-96 h) in a hololimnetic population of the Amazon River shrimp Macrobrachium amazonicum from the Paraná/Paraguay River basin, including the effects of exposure to 4.93 mg L-1 total ammonia concentration on gill (Na+, K+)-ATPase activity. The mean LC50-96 h was 49.27 mg L-1 total ammonia, corresponding to 1.8 mg L-1 un-ionized ammonia. Except for NH4+ affinity that increased 2.5-fold, that of the gill (Na+, K+)-ATPase for ATP, Mg2+, Na+, K+ and ouabain was unchanged after ammonia exposure. Western blotting of gill microsomal preparations from fresh caught shrimps showed a single immunoreactive band of ≈110 kDa, corresponding to the gill (Na+, K+)-ATPase α-subunit. Ammonia exposure increased (Na+, K+)-ATPase activity by ≈25%, coincident with an additional 130 kDa α-subunit immunoreactive band, and increased K+-stimulated and V(H+)-ATPase activities by ≈2.5-fold. Macrobrachium amazonicum from the Paraná/Paraguay River basin is as tolerant to ammonia as are other Amazon River basins populations, showing toxicity comparable to that of marine crustaceans.
Subject(s)
Palaemonidae , Water Pollutants, Chemical , Ammonia/toxicity , Animals , Gills , Ions , Kinetics , Rivers , Sodium/pharmacology , Sodium-Potassium-Exchanging ATPase/metabolism , Water Pollutants, Chemical/toxicityABSTRACT
ABSTRACT Introduction: Many cerebrovascular diseases display a relation with inflammatory processes. Furthermore, the influence of several polymorphisms has been studied to improve the knowledge of physiological mechanisms of the nervous system. Objectives: The aim of this study was to identify if there was an association between a polymorphism in -308 position of the TNFA gene and the development of hemorrhagic stroke or aneurysm in Distrito Federal, Brazil. Methods: We collected the clinical information and the medical records from hemorrhagic stroke or aneurysm patients. The occurrence of stroke or aneurysm was confirmed by computed tomography (CT) or magnetic resonance image (MRI). The TNFA genotypes were determined by polymerase chain reaction restriction fragment length polymorphism. Results: The AG genotype appears to decrease the occurrence of hemorrhagic stroke or aneurysm in people between 45-63 years. Our study was the first to investigate this association in a Brazilian sample, although a previous report showed a similar effect with ischemic stroke in a Chinese population. Conclusion: The TNFA -308 AG genotype is associated with a decreased risk of aneurysm or hemorrhagic stroke in a population from the capital of Brazil, Distrito Federal.
RESUMO Introdução: Muitas doenças cerebrovasculares relacionam-se com processos inflamatórios, portanto, a influência de vários polimorfismos em doenças tem sido estudada para melhorar o conhecimento sobre os mecanismos fisiológicos do sistema nervoso. Objetivo: Identificar a associação entre um polimorfismo na posição -308 do gene TNFA e o desenvolvimento de acidente vascular encefálico hemorrágico (AVEH) ou aneurisma em pacientes de uma base hospitalar do Distrito Federal, Brasil. Métodos: Foram coletados os prontuários e as informações clínicas de pacientes com AVEH ou aneurisma. A caracterização dos grupos caso foi confirmada por tomografia computadorizada (TC) ou ressonância nuclear magnética (RNM). Os genótipos do gene TNFA foram determinados por técnica do polimorfismo de comprimento dos fragmentos de restrição do produto obtido pela reação em cadeia da polimerase (PCR). Resultados: O genótipo AG parece diminuir a ocorrência de AVEH ou aneurisma em indivíduos entre 45 e 63 anos. Nosso estudo foi o primeiro a investigar essa associação em uma amostra brasileira, embora um relatório anterior tenha mostrado efeito semelhante com o acidente vascular encefálico isquêmico em uma população chinesa. Conclusão: O genótipo TNFA -308 AG está associado à diminuição do risco de aneurisma ou AVEH em uma população da capital do Brasil, Distrito Federal.
