The analysis of free tryptophan in human blood with the ultrafiltrator: A comparison with other methods

Baumann, Pierre; Perey, M

doi:10.1016/0009-8981(77)90100-0

Cited by 20 publications

(3 citation statements)

References 31 publications

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“…The observed large within-patient variability in free plasma tryptophan levels may, however, have obscured any alterations due to ECT and/or recovery. This variability is unlikely to be related entirely to changes in plasma pH during ultracentrifugation (Baumann & Perey, 1977), since in 3 patients levels of free plasma tryptophan were increased in samples which showed no significant change in pH. The stress of ECT with consequent adrenocortical activation and increase in the level of circulating free fatty acids (Taggart & Carruthers, 1971;Curzon & Knott, 1975) could explain the observed high levels of free plasma tryptophan.…”

Section: Discussionmentioning

confidence: 94%

Effect of electroconvulsive therapy (ECT) on plasma tryptophan

Whalley¹,

Yates²,

Christie³

1980

Psychol. Med.

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SYNOPSISThe concentrations of total and free plasma tryptophan were measured in 12 unipolar depressed patients before and after a course of electroconvulsive therapy (ECT) and before and after single ECTs during the course of treatment. Eleven patients undergoing diagnostic cystoscopy served as controls to examine the acute effect of anaesthesia. Total and free plasma tryptophan concentrations in the depressed patients were not significantly different from control values and were not changed by the course of ECT. Free plasma tryptophan varied considerably within individual patients. Total plasma tryptophan was reduced acutely by ECT/anaesthesia in the depressed patients (P < 0·05) and by anaesthesia in the cystoscopy controls (P < 0·01). Free plasma tryptophan was not significantly altered. This reduction in total plasma tryptophan could be secondary to an effect of thiopentone on albumin binding of tryptophan.

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Section: Discussionmentioning

confidence: 94%

Effect of electroconvulsive therapy (ECT) on plasma tryptophan

Whalley¹,

Yates²,

Christie³

1980

Psychol. Med.

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“…Moreover, at room temperature (> 4 o C), serum TRP and the CAA may increase in plasma (personal observations), which may be explained by increased protease activity which release amino acids. Moreover, also heparin tubes may not be appropriate to assay TRP as heparin may interact with binding of albumin to TRP 121,122 . Another source of variation in plasma/serum TRP levels is associated with blood platelets, which have high concentrations of TRP and 5-HT and may release TRP when activated.…”

Section: Sources Of Heterogeneity In Trycats Studiesmentioning

confidence: 99%

The tryptophan catabolite or kynurenine pathway in schizophrenia: meta-analysis reveals dissociations between central, serum, and plasma compartments

et al. 2022

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“…Moreover, at room temperature (> 4 °C), serum TRP and the CAA may increase in plasma (personal observations), which may be explained by increased protease activity which release amino acids. Moreover, also heparin tubes may not be appropriate to assay TRP as heparin may interact with binding of albumin to TRP 121, 122 . Another source of variation in plasma/serum TRP levels is associated with blood platelets, which have high concentrations of TRP and 5-HT and may release TRP when activated.…”

Section: Discussionmentioning

confidence: 99%

The tryptophan catabolite or kynurenine pathway in schizophrenia: meta-analysis reveals dissociations between central, serum and plasma compartments

Almulla

Maes

Tunvirachaisakul

et al. 2021

Preprint

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The tryptophan catabolite (TRYCAT) pathway is implicated in the pathophysiology of schizophrenia (SCZ) since the rate-limiting enzyme indoleamine-dioxygenase (IDO) may be induced by inflammatory and oxidative stress mediators. This systematic review searched PubMed, Web of Science, and Google Scholar for papers published from inception until August 2021 and meta-analyzed the association between SCZ and TRYCATs in the central nervous system (CNS) and peripheral blood. We included 61 studies comprising 2813 patients and 2948 healthy controls. In the CNS we found a significant (p<0.001) increase in the kynurenine/tryptophan (KYN/TRP) (standardized mean difference, SMD=0.769, 95% confidence interval, CI: 0.456; 1.082) and kynurenic acid (KA)/KYN+TRP (SMD=0.697, CI:0.478-0.917) ratios, KA (SMD=0.646, CI: 0.422; 0.909) and KYN (SMD=1.238; CI: 0.590; 1.886), while the 3OH-kynurenine (3HK) + KYN-3-monooxygenase (KMO)/KYN ratio was significantly reduced (SMD=-1.089, CI: -1.682; -0.496). There were significant differences between KYN/TRP, (KYN+KA)/TRP, (3HK+KMO)/KYN, KA, and KYN levels among the CNS and peripheral blood, and among serum and plasma KYN. The only useful peripheral marker of CNS TRYCATs findings was the increased KYN/TRP ratio in serum (SMD=0.211, CI: 0.056; 0.366, p=0.007), but not in plasma. There was no significant increase in a neurotoxic composite score based on KYN, 3HK, and picolinic, xanthurenic, and quinolinic acid. SCZ is accompanied by increased IDO activity in the CNS and serum, and reduced KMO activity and a shift towards KA production in the CNS. This CNS TRYCATs profile indicates neuroprotective, negative immunoregulatory and anti-inflammatory effects. Peripheral blood levels of TRYCATs are dissociated from CNS findings except for a modest increase in serum IDO activity.

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The analysis of free tryptophan in human blood with the ultrafiltrator: A comparison with other methods

Cited by 20 publications

References 31 publications

Effect of electroconvulsive therapy (ECT) on plasma tryptophan

Effect of electroconvulsive therapy (ECT) on plasma tryptophan

The tryptophan catabolite or kynurenine pathway in schizophrenia: meta-analysis reveals dissociations between central, serum, and plasma compartments

The tryptophan catabolite or kynurenine pathway in schizophrenia: meta-analysis reveals dissociations between central, serum and plasma compartments

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