Asunto(s)
Ácidos y Sales Biliares/metabolismo , Bacterias Gramnegativas/metabolismo , Pseudomonas/metabolismo , Esteroles/metabolismo , Biodegradación Ambiental , Ácido Desoxicólico/metabolismo , Bacterias Gramnegativas/ultraestructura , Calor , Microscopía Electrónica de Rastreo , Plantas , Sitoesteroles/metabolismoRESUMEN
The occurrence of vanadium in the biosphere, and the possible roles this element may play in the metabolism of living organisms, especially higher plants, are discussed. The aqueous chemistry of the element is reviewed, and the chemical properties of the element are related to those of soils and plants. Evidence is present for a biotransformation of vanadium from vanadate (VO 3 (-) ) to vanadyl (VO(2+)) during uptake by plants, based on tissue analysis and ESR spectra. The significance of this process on the potential impact of vanadium in the biosphere is discussed.
RESUMEN
Plasma, obtained from 131 nondepressed, otherwise healthy subjects aged from 17 to 102 years, and 22 depressed subjects aged over 70 years, was analysed for total and free tryptophan. Variation with age was found in total tryptophan. This association has not been described hitherto. There was a significant increase in total tryptophan and a non-significant increase in free tryptophan with depression. This is in contrast to some studies in younger people showing a decline in plasma tryptophan in depressed subjects.
Asunto(s)
Envejecimiento , Depresión/sangre , Triptófano/sangre , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Albúmina SéricaAsunto(s)
Catarata/sangre , Triptófano/sangre , Anciano , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
The application of equilibrium dialysis to the determination of the "free", i.e. non-albumin bound fraction of human plasma or serum tryptophan has been re-examined. A potentially serious error in the application of this method is outlined and the necessary correction and some precautionary measures are discussed.