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Biomedical subjects

D Tomková

Publications and source records attributed to D Tomková.

At least 19 recordsLinked to original sources
PubMed1994

[Renal excretion of amino acids in patients on a regular dialysis program].

In 10 patients with chronic renal failure and a polyfructosan S clearance (CPFS): 1.91-12.70 ml/min (mean 5.68 ml/min) with a preserved residual diuresis (more than 1000 ml/24 hours) renal excretion of 22 amino acids by residual nephrons was investigated before and 12 hours after haemodialysis. It was revealed that 12 hours after haemodialysis a significant drop of the filtered amount of all investigated amino acids occurred. Renal clearance of Ser, Pro, Glu, Gly, Ala, Tyr, Met, Leu and Cit after haemodialysis declined significantly (p < 0.05-0.001). Haemodialysis was not associated with significant changes of fractionated excretions (FE) of amino acids with the exception of Gly (p < 0.01) and Trp (p < 0.05) where an increase of FE was recorded. Hitherto assembled results are consistent with the idea that a reduction of the tubular resorption of amino acids in the residual nephrons in subjects with chronic renal failure cannot be explained by a change of their filtered amount (as "overflow" aminoaciduria) nor as the consequence of retention of some dialyzable substances which could inhibit tubular transport of amino acids. The reduced tubular transport of some of the investigated amino acids (Cys, Lys, Cit, Met, Asn+Gln, Orn, Ile) was significantly related with the drop of tubular sodium transport.

Adult↗
PubMed1991

Renal amino acid excretion and aging.

The urinary excretion and serum concentration of amino acids were studied in 62 healthy individuals aged 15 to 70 years. In elderly subjects (61-70 years), it was found that renal amino acid clearance per 100 ml GFR (fractional excretion, FE) rose significantly in the following amino acids: CYS, VAL, MET, ILE and LEU. Since the serum concentrations of these amino acids showed no significant changes, but the GFR was reduced, it can be concluded that the raised FE of these amino acids was due to a decrease in their effective tubular reabsorption. A significant correlation was found between FENa and FE of most amino acids including those mentioned above. The findings support the assumption that changes in tubular Na+ transport probably participate in the changes of tubular amino acid transport in elderly individuals.

Adolescent↗
PubMed1981

Optimal amino acid composition of diets for patients with chronic renal failure.

When following the spectrum of plasmatic amino acids in patients with chronic renal failure in course of a six-week treatment with low-protein diets, an increase of non-essential amino acids, glycine and alanine, was observed in the case of a diet containing 20 g of proteins. A further decrease of tyrosine and threonine, which were decreased already before the therapy, suggests the presence of an effect of the reduced intake of proteins on the levels of these amino acids. High levels of methionine occurring in the case of the diet containing 20 g of proteins a day, supplemented by methionine to a minimally necessary requirement according to Rose, show different requirements) for this amino acid in patients with the chronic renal failure. A significant drop of the histidine and arginine as compared to the values before the treatment demonstrated that it is also necessary to take into account these amino acids when composing optimal amino acid formulation for uremics. A preliminary proposal is presented of a composition of amino acid mixture suitable for patients with chronic renal failure which differs essentially from the Rose formulation developed for a healthy organism. Different requirements for arginine are also considered in addition to the essential amino acids and histidine.

Adult↗
PubMed1978

Renal clearance of amino acids in patients with severe chronic renal failure.

The renal clearance of 21 amino acids was investigated in 5 patients with chronic renal failure (inulin clearance = 5--10ml/min) during the 6-week administration of a low-protein diet. The results were compared with values obtained in 6 volunteers. The renal clearance of all investigated amino acids (with the exception of Asp, His, Tau) did not differ significantly from healthy controls. The excretion fraction (amino acid clearance inulin clearance.100) was in all investigated amino acids significantly higher than in controls with the exception of Tau. The excretion fractions of Asp, Ser, Cys, Tyr, His, Thr, Tau and Gly were, on average, above 20%. The findings suggest that the fractional reabsorption of amino acids in residual nephrons is decreased.

Adult↗
PubMed1978

Amino acid metabolism in the heart muscle in subjects with ischaemic heart disease at rest and during pacing.

In nine patients with ischaemic heart disease at rest and during pacing differences of free plasma amino acids, lactate, ammonia and uric acid between arterial blood and blood in the coronary sinus (a-cs differences) were investigated. At rest one single significant difference was found, i.e. a positive a-cs difference in aspartate. During pacing significant positive differences were recorded in aspartate, glutamate, leucine and isoleucine and significant negative a-cs differences in cystine-cysteine, glutamine and aspartic acid and in alanine. Among the correlations between a-cs differences the negative relationship between lactate and alanine and the negative correlation between cystine-cysteine and leucine, isoleucine and glutamine is significant. There is a positive relationship between the a-cs difference of alanine and glutamine and between the differences of leucine, isoleucine and glutamate. The a-cs differences of ammonia and uric acid correlate negatively.

Adult↗
PubMed1976

Changes of free amino acids in plasma of healthy subjects induced by physical exercise.

In eight healthy men a 20-min load of 1.5 W/kg body weight on a bicycle ergometer led to a significant increase of alanine and decline of leucine. Exhausting exercise caused in the same subjects a highly significant increase of alanine and decline of isoleucine, threonine, ornithine, leucine, serine, glycine, and asparasine and glutamine. The methionine and citrulline level declines also significantly. The total amino acids practically did not change. Physical exercise led furthermore to a marked increase of serum ammonia and uric acid. Urea nitrogen changed only little and on average had rather a declining tendency. The rise of alanine suggests the existence of a glucose-alanine cycle, the drop of ornithine and citrulline is most probably associated with the inhibition of ureogenesis in the liver. The reduction of leucine and isoleucine is probably the result of the entry of these amino acids into muscle and their deamination.

Adult↗