Determination of free and bound plasma tryptophan by ultrafiltration

Baumann, Pierre; Duruz, Eliane; Heimann, H

doi:10.1016/0009-8981(74)90058-8

Cited by 16 publications

(4 citation statements)

References 8 publications

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“…Many studies have been reported (18,(24)(25)(26) on the Separation of free tryptophan from plasma, but the results were not satisf ctory beca se equilibrium between free tryptophan and bound tryptophan changed d ring Separation of the free tryptophan fraction.…”

Section: Discussionmentioning

confidence: 99%

“…Ultrafiltration of plasma in Amicon membrane cones with control of pH was successful and convenient for obtaining the free tryptophan fraction^ and this method in combination with HPLC was better for determination Of free tryptophan than any method reported already (16,(18)(19)(20). In this work we examined the effect of pH of plasma d ring centrifugation on the free tryptophan concentration of the filtrate.…”

Section: Discussionmentioning

confidence: 99%

“…In previous reports, the plasma tryptophan is assayed without separating the tryptophan (16,(18)(19)(20), so that contaminants in the sample influence .the value for the tryptophan concentration. Therefore, f rther application of high performance liquid chromatography (HPLC) is useful for the specific determination of tryptophan in the plasma.…”

Section: Introductionmentioning

confidence: 99%

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Determination of Free Tryptophan in Plasma and Its Clinical Applications

Hijikata¹,

Hara²,

Shiozaki³

et al. 1984

Clinical Chemistry and Laboratory Medicine

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Summary: Free tryptophan in plasma was separated by centrifugation through an Amicon Ultrafiltration membrane cone. The value obtained without control of pH was found to be lower than that obtained with control of pH by an improved method (Hijikata et al. (1981) Anal. Biochem. 118, 10-16).For determination of the total tryptophan concentration in the plasma, high performance liquid chromatography (HPLC) was better than the method of Denckla Dewey s modified by Bloxam & Warren ((1974) Anal. Biochem. 60,[621][622][623][624][625], s judged on the basis of sensitivity, recovery rate and coefficient of variance. The total tryptophan concentration in the plasma determined by HPLC was lower than that determined by theThe total tryptophan concentration (t-Trp), free tryptophan concentration (f-Trp) and f-Trp/t-Trp ratio were 55.8 ± 10.2 μιηοΐ/ΐ, 11.6 ± 1.5 μίηοΐ/ΐ and 0.211 ± 0.03 (mean ± l SD) respectively, in healthy subjects (co trols). No significant difference was observed between the values of controls and those of patients with liver cirrhosis, hepatocellular carcinoma, liver cirrhosis with hepatocellular carcinoma and hepatic encephalopathy of liver cirrhosis without bleeding. But in liver cirrhosis with bleeding, free tryptophan concentration (f-Trp, 48.0 ± 23.3 μτηοΐ/ΐ, p < 0.001) and f-Trp/t-Trp ratio (0.645 ± 0.289, p < 0.001) were significantly higher than those of controls. In fulminant hepatitis free tryptophan concentration, (f-Trp, 106.6 ± 79.9 μιηοΐ/ΐ, p < 0.02), and f-Trp/t-Trp ratio (0.973 ± 0.017, p < 0.001) were significantly higher than those of controls, and free tryptophan concentration (f-Trp) and f-Trp/t-Trp ratio (p < 0.005) were significantly higher than in liver cirrhosis with bleeding. In other words the increase of free tryptophan concentration in plasma may be related to the bleeding, and in fulminant hepatitis the binding ability of free tryptophan to albumin may decrease. In the examined cases of liver cirrhosis, the correlation of the concentration of plasma tryptophan with those of other amino acids and indicators of liver function was changed when hepatocellular carcinoma was also present.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of Free Tryptophan in Plasma and Its Clinical Applications

Hijikata¹,

Hara²,

Shiozaki³

et al. 1984

Clinical Chemistry and Laboratory Medicine

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“…For biodaemical determinations, free tryptophan was obtained by uItrafiltration of the plasma (Baurnann et al, 1974). Total and free tryptophan (Denckla and Dewey, 1967) and tyrosine (Waalkes and Udenfriend, 1957) were determined fluorometrically in the blood plasma.…”

Section: Introductionmentioning

confidence: 99%

Insulin coma therapy: Decrease of plasma tryptophan in man

Baumann

Gaillard

1976

J. Neural Transmission

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A biochemical study was performed in two patients submitted to insulin coma therapy. The injection of insulin resulted in a decrease of free and total tryptophan as well as tyrosine in plasma, while NEFA were not influenced by this treatment. The ratio of tryptophan to tyrosine was enhanced. The administration of glucose after insulin provoked an increase of free and total tryptophan. The results support the hypothesis that in man insulin may favor the uptake of tryptophan by the brain, and enhance the synthesis of cerebral serotonin.

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Preoperative and postoperative levels of plasma protein and amino acid in esophageal and lung cancer patients

Naini

Dickerson

Brown

1988

Cancer

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The metabolic changes following thoracic surgery in three groups of patients (esophageal cancer, lung cancer, and hiatus hernia) have been studied. Before operation patients with esophageal cancer, but not those with lung cancer, had significantly lower plasma total protein and albumin than patients with hiatus hernia. After surgery plasma albumin and total protein fell in both esophageal cancer and hiatus hernia patients, a development attributed to poor nutrition and restricted calorie diet in these two groups of patients respectively. With the exception of alanine and arginine in lung cancer patients, and free tryptophan in lung and esophageal cancer patients, the preoperative concentrations of all plasma amino acids were similar in both groups of cancer patients and in those with hiatus hernia. After operation the concentrations of glutamine, total tryptophan, alanine, glycine, and arginine fell sharply, whereas those of phenylalanine, lysine, valine, and leucine were slightly or not at all affected by surgery. The immediate postoperative fall of plasma free amino acids is thought to be due to the increased rate of gluconeo-genesis. The rise of free fraction of plasma tryptophan after surgery is related to the raised level of plasma free fatty acids and increased secretions of catecholamines, which is believed to follow surgery. Cancer 623355360, 1988. ATIENTS with esophageal cancer are frequently P malnourished as a result of reduced food intake, and their rehabilitation after surgery is often protracted. After esophagectomy fat absorption has been reported to be impaired.' These workers have also reported that after esophagectomy there is a rise in the excretion of the nitrogen in the feces. Although Wu and Bauer observed a relatively large increase in the plasma free amino acid levels to accompany tumor growth,2 recent studies by Norten et al., have shown that cancer patients with no or minimum body weight loss maintained their plasma free amino acid levels within normal range.3 Of the amino acids, the metabolism of tryptophan in malignant disease has attracted much interest in recent years. However, most of the studies on tryptophan metabolism have been carried out in patients with cancer of the bladder or It seemed to be of particular interest to study the metabolism of this amino acid in patients with esophageal cancer because its concentration in the plasma is reduced sharply by a reduced food intake and in particular

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Determination of free and bound plasma tryptophan by ultrafiltration

Cited by 16 publications

References 8 publications

Determination of Free Tryptophan in Plasma and Its Clinical Applications

Determination of Free Tryptophan in Plasma and Its Clinical Applications

Insulin coma therapy: Decrease of plasma tryptophan in man

Preoperative and postoperative levels of plasma protein and amino acid in esophageal and lung cancer patients

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