Differences of Plasma Levels of Tryptophan, Serotonin, 5-Hydroxyindole Acetic Acid, and Kynurenine between Healthy People and Patients of Major Monopolar Depression at Various Age and Gender

Background: It is not well analyzed whether there are differences in plasma levels of tryptophan (TRP) metabolites between healthy control people (HC) and patients of major monopolar depression (MMD). Methods: Ultra high-speed liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive patients. Results: There are no significant differences between plasma levels of TRP between HC and MMD. Plasma levels of TRP of HC are higher in young men, young women, old men, and old women in this order. Serotonin (5-HT) levels are higher in MMD than HC. Plasma levels of 5-HIAA of HC are also higher than those of patients of MMD. Plasma levels of kynurenine (KYN) of healthy old men and old women are higher than those of young men and old women. Plasma levels of KYN are higher in old women and young men of MMD than those of HC. Conclusion: Plasma levels of 5-HT are higher in patients of MMD than those of HC, which may suggest that use of drugs inhibiting the 5-HT transportation may increase plasma levels of 5-HT in MMD.

Effects of Gender, Age, and Clot Formation on the Measurements of Tryptophan Metabolites in Blood

Background: Tryptophan metabolism plays important roles in health and diseases. Although simultaneous measurements of tryptophan metabolites are successfully measured, influences of age, gender, and clot formation on the measurements have not been reported. Methods: We took blood from young and old Japanese men and women and compared plasma levels of tryptophan metabolites. We also took plasma and serum from the blood of middle-aged men (n = 10). Metabolites analysis was performed by a liquid chromatograph tandem mass spectrometer, the LCMS-8060 quadrupole mass spectrometer combined with Nexera X2 liquid chromatograph system (Shimadzu Corporation, Kyoto, Japan). Body mass index (BMI) and TRP metabolites have been measured in healthy young men (n = 48), young women (n = 47), old men (n = 44), and old women (n = 39). TRP metabolites were measured by using the ultrahigh speed liquid chromatography-mass spectroscopy (Shimadzu Corporation). Results: Tryptophan and its metabolites such as serotonin, 5-hydroxyindole acetic acid, indole-3-acetic acid, kynurenine, anthranilic acid, were higher in young women and old men than young men and old women. Plasma levels of 3-hydroxykynurenine and xanthurenic acid were lower in young women and old men. Comparison of plasma and serum indicates that most of metabolites were higher in serum than plasma except for 3-hydroxy-kynurenine and quinolinic acid. Conclusion: Metabolites of the upper stream of degradation of tryptophan were higher in young women and old men than young men and old women, which suggests that the degradation of tryptophan was accelerated in young men and old women than young women and old men. Serum preparation may activate tryptophan degradation resulting in higher levels of metabolites in serum than in plasma.

Comparison of Age and Gender Differences of Tryptophan Metabolites in Patients of Major Monopolar and Bipolar Depression

Background: No research has been done for the determination of plasma levels of tryptophan metabolites in patients of monopolar and bipolar depression. Methods: Ultra high-speed liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive patients. Results: No significant age and gender differences were shown in monopolar depressive patients and some differences were shown in bipolar patients. The administration of drugs such as antidepressants, antipsychotics, mood stabilizers do not seem to have affected the results. Conclusion: In patients of major monopolar depression age and gender differences of plasma levels of tryptophan metabolites disappear although significant differences are observed in healthy volunteers. Some differences of age and gender differences were shown between monopolar and bipolar depressive patients.

Al^(3+)/graphene composites for electrochemical detection of DNA cleavage

Herein, we present the electrochemical co-deposition of Al3+/graphene composites directly from an aqueous mixture containing graphene oxide (GO) and Al3+. The obtained Al3+/graphene composites with good electrochemical activity were regarded as an appropriate immobilization platform for double-stranded DNA (dsDNA). The nontoxic redox probe xanthurenic acid (XA) was successfully applied to recognize single-stranded DNA and dsDNA. We illustrated that the scission of dsDNA caused by GO combining with some metal ions could be detected by monitoring the electrochemical signals of XA.