E Herrero Huerta | PubMed Health

PubMed1994

[Selenium: the physiopathological and clinical implications].

Selenium is an ultra-trace element widely distributed in the environment, although its consumption varies significantly depending on the region. Its daily requirements range between 50 and 200 micrograms/day (or a minimum of 1 microgram/kg/day), which are supplied by animal and vegetal foods. Its essentiality in human nutrition is derived from its antioxidative action, being a part of the glutation-peroxidase system (GPx). Thus, it is a protective agent against the harmful action of free radicals. Determination of the selenium-dependent GPx activity seems to be the best index for the assessment of nutritional status. A deficit of selenium will result in a decrease of the GPx activity and, therefore, in a increase of cell damage which cannot be counter-balanced by other antioxidative systems. Diet has a relevant role for the maintenance of selenium status. Deficiency conditions may appear in different population groups when the selenium content in the diet is inadequate. Toxicity states are rare, but some diseases are sensitive to this element, which is mainly involved in cancer prevention.

Adult↗

PubMed1979

[Role of secondary hyperaldosteronism in the pathomecanism of hydropic decompensation in the cirrhotic patient (author's transl)].

Plasma aldosterone levels before and after walking were compared in a series of 10 controls and 41 patients with cirrhosis of the liver. The latter were distributed in the following way: 8 had compensated cirrhosis, the remaining 33 were in a situación of hydropic decompensation, 10 with associated renal insufficiency, and 23 without. Basal aldosterone levels in compensated cirrhotics were similar to those of the controls, but these values increased significantly more than the controls following postural stimulation. Decompensated cirrhotics without renal insufficiency had significantly higher values than the controls, both in basal conditions and after stimulation. The highest values corresponded to the decompensated cirrhotic patients with renal insufficiency who were in advanced stages of liver disease. On the basis of the present findings and those of other authors, it is suggested that a certain reduction in the metabolic clearance of aldosterone appears to exist in hepatic cirrhosis. However, hormonal hyperproduction is the dominant factor in the pathogenic mechanism of secondary hyperaldosteronism. The pathogenesis of the excessive production of hormone is discussed. In conclusion, it appears that the scant affluence of sodium to the macula densa may be the primary factor in explaining this common situation in patients with cirrhosis of the liver.

Adult↗