Arterial whole blood levels of amino acids were determined in patients with chronic renal failure and in healthy subjects before and after 270 min after the ingestion of a grilled beefsteak (4 g/kg). ...In patients, total nonessential amino acids increased significantly more (+46%) than in controls owing to an exaggerated rise of serine, glutamine, proline, glycine, cyst(e)ine and alanine. Total essential amino acids increased as much as in controls; however, threonine, histidine and phenylalanine showed greater increases, while tryptophan had a smaller increment. Abnormalities in amino acid levels were even more evident in the postprandial period than in the postabsorptive state owing to reduced levels of valine, leucine, tryptophan, tyrosine, aspartate and glutamate and higher levels of glutamine, proline, glycine, cyst(e)ine, threonine, histidine and phenylalanine. Moreover, after the meal, the ratios total essential amino acids/total nonessential amino acids, valine/glycine, and branched-chain amino acids/total amino acids rose but persisted to be reduced whereas tryptophan/total amino acids and tyrosine/phenylalanine ratios increased in controls, but did not change in patients. In conclusion, in chronic renal failure, protein ingestion enhances the imbalance in amino acid levels already present in the postabsorptive state. The all data indicate that in patients with chronic renal failure, the metabolism of exogenous protein is impaired and the flow of amino acids to the organs is altered during the phase of body nitrogen replenishment.
Cognitive disorders among welders exposed to aluminum Giorgianni, C; Faranda, M; Brecciaroli, R ...
Giornale italiano di medicina del lavoro ed ergonomia,
2003 Jul-Sep, Letnik:
25 Suppl, Številka:
3
Journal Article
Recenzirano
In order to evaluate the relationship between exposure to aluminum and cognitive functions, a group of 50 aluminum welders underwent to the following neuropsychological tests: Wechsler Memory Scale, ...Color-Word Test and Raven Progressives Matrices test. The results of the tests showed a reduction of memory, of concentration and a slight reduction of attention. The authors conclude that aluminum exposure leads cognitive changes.
Arterial whole blood levels of amino acids (AA) were determined in patients with chronic renal failure (CRF) and in healthy volunteers before and for 75 min after the ingestion of an AA mixture ...simulating the AA content of an animal-protein meal. In CRF patients, total AA increased more than in control subjects as a consequence of an exaggerated rise in nonessential AA (+86%), mainly glutamine, proline, glutamate, serine, glycine, and alanine. Total essential AA in patients increased as much as in control subjects; however, threonine and phenylalanine showed greater increases while leucine had a smaller increase. As a consequence of the observed alterations, a striking unbalance in the postprandial pattern of arterial AA ensued in CRF patients. The flow of AA to all the organs is altered during the absorptive phase, which is crucial for body nitrogen-pool replenishment.
Metabolic acidosis causes a cooperative participation of different organs such as the liver, kidney, and muscle in restoring acid-base balance. In splanchnic organs, metabolic acidosis has ...repercussions on several nitrogen metabolism pathways. The decrease in urea synthesis due to reduced activity of urea cycle enzymes, ammonia uptake and amino acid transport, and changes in glutamine metabolism support renal ammoniagenesis thus offering a response to rid the body of excess protons. While some of the mechanisms are adaptive others may be harmful for the body. Metabolic acidosis may have effects on splanchnic protein turnover. In severe acidosis, synthesis of secreted liver proteins may be reduced. Acidosis may also modulate the response of the liver to growth hormone (GH) for insulin-like growth factor-I synthesis, thus inducing a state of GH resistance. Splanchnic abnormalities in acidosis might contribute to the malnutrition observed in uremia.
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