China
Africa
Explore chapters and articles related to this topic
Hyperphenylalaninemia and defective metabolism of tetrahydrobiopterin
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
Each of these defects leads to a situation in which phenylalanine cannot be converted to tyrosine, even though the phenylalanine hydroxylase apoenzyme is normal. Tetrahydrobiopterin is also the cofactor for the hydroxylation of tryptophan and tyrosine. Thus, its deficiency interferes with the synthesis of serotonin, DOPA, and norepinephrine. Data have been obtained that indicate that this is the case, since levels of 5-hydroxyindoleacetic acid, vanillylmandelic acid, and homovanillic acid in CSF are considerably lower than normal [6, 23]. Low levels of dopamine and serotonin have also been documented in urine [8, 29]. Since it is possible in these disorders to have severe neurologic disease in the presence of only mild HPA, levels of BH4 may be relatively more sufficient for phenylalanine hydroxylation than that of tryptophan or tyrosine [7, 36, 37]. Defective neurotransmitter metabolism is doubtless related to the genesis of neurologic abnormalities.
Diseases of the Nervous System
Published in George Feuer, Felix A. de la Iglesia, Molecular Biochemistry of Human Disease, 2020
George Feuer, Felix A. de la Iglesia
Several reports indicate that serotonin metabolism may also be implicated in affective illnesses.528,541 A decrease of 5-hydroxyindole acetic acid, the major metabolite of serotonin, is found in the cerebrospinal fluid of depressed patients. However, the level of this compound is not restored to normal upon clinical recovery. Further, 5-hydroxyindole acetic acid is reduced in early mania, but some studies revealed no differences in 5-hydroxyindole levels in the cerebrospinal fluid between depressed and schizophrenic patients. The urinary excretion of 5-hydroxyindole acetic acid is significantly greater during the manic than the depressed state. Patients suffering from retarded depression with apathy excrete more of this metabolite than patients with agitated depression and anxiety.
How Antidepressants Work, but Often Do Not
Published in Scott Mendelson, Herbal Treatment of Major Depression, 2019
First, there is no clear evidence that people suffering MDD actually have low levels of serotonin in their brains. Measurement of serotonergic activity inside the brains of living subjects has been a technically difficult task. Most of the early studies have examined levels of the main metabolite of serotonin, 5-hydroxyindoleacetic acid (5-HIAA), in the cerebrospinal fluid. Not all such studies have found the expected decreased levels of 5-HIAA. Moreover, when decreases are found, the degree of depletion has not correlated with severity of depression. Curiously, the cerebrospinal fluid of depressed patients treated with antidepressants has tended to contain decreased levels of 5-HIAA, suggesting that these medications reduced serotonergic activity.5 For example, in a 2008 study, levels of the serotonin metabolite 5-HIAA were measured in blood coming from the brain in the jugular vein. It was found that those levels were higher in depressed patients, and that levels decreased after treatment with SSRIs.6
Nordic guidelines 2021 for diagnosis and treatment of gastroenteropancreatic neuroendocrine neoplasms
Published in Acta Oncologica, 2021
Eva Tiensuu Janson, Ulrich Knigge, Gitte Dam, Birgitte Federspiel, Henning Grønbaek, Peter Stålberg, Seppo W. Langer, Andreas Kjaer, Johanna Arola, Camilla Schalin-Jäntti, Anders Sundin, Staffan Welin, Espen Thiis-Evensen, Halfdan Sorbye
Serum CgA (s-CgA) is the most commonly used biomarker in blood and elevated in the majority of patients with residual NETs. The serum concentration at baseline is a predictor of patient outcome [8]. S-CgA should not be used for screening since the specificity is hampered by proton pump inhibitors, kidney, liver and heart failure, chronic atrophic gastritis, as well as several non-neuroendocrine malignancies. Furthermore, GEP-NENs may have normal s-CgA levels. The value of s-CgA for therapy monitoring and surveillance has been investigated in retrospective studies showing that s-CgA is a specific and sensitive marker of tumour progression and that basal s-CgA levels can predict overall survival [8,9]. However, in a recent prospective multicenter study, there was only a weak association between change in s-CgA and change in tumour burden [10]. Overall, s-CgA as a single plasma biomarker is inadequate to predict tumour progression and must be used in association with imaging follow-up. The role of emerging biomarker panels such as the NETestTM, has to be determined [11]. Depending on the primary tumour and symptoms of the patient, measurement of specific markers, such as gastrin, insulin, c-peptide, pro-insulin, glucagon, VIP, somatostatin, ACTH or calcitonin should be performed. In small intestinal NETs (SI-NETs), 5-hydroxyindoleacetic acid (5HIAA) is often elevated and should be measured, preferably in blood [12]. N-terminal pro-brain natriuretic peptide (NT-pro-BNP) can be useful for detection of carcinoid heart disease (CHD) [13].
Influences of exposure to 915-MHz radiofrequency identification signals on serotonin metabolites in rats: a pilot study
Published in International Journal of Radiation Biology, 2021
Hye Sun Kim, Man-Jeong Paik, Chan Seo, Hyung Do Choi, Jeong-Ki Pack, Nam Kim, Young Hwan Ahn
Serotonin (5-hydroxytryptamine) is a monoamine neurotransmitter also known as a ‘happy chemical’ that can modulate various neurological mechanisms such as mood, sleep, circadian rhythm, learning, memory, and stress (Berger et al. 2009; Weng et al. 2015). Serotonin deficiency is observed in a broad range of diseases, including various neurodegenerative diseases and depression (Berger et al. 2009; Weng et al. 2015). One of the main metabolites of serotonin is 5-hydroxyindoleacetic acid (5-HIAA), the urinary concentration of which is an index of turnover of its parent neurotransmitters in the central nervous system (Sullivan et al. 2006). Changes in serotonin turnover caused by various environmental stressors can lead to decreased urinary levels of 5-HIAA (Tarantino et al. 2011). Urinary levels of 5-HIAA are used for diagnosing intestinal neuroendocrine tumors, and high levels indicate the need for follow-up (Tarantino et al. 2011).
The path to surgery in carcinoid heart disease: a retrospective study and a multidisciplinary proposal of a new algorithm
Published in Acta Cardiologica, 2019
Philippe Mortelmans, Marie-Christine Herregods, Filip Rega, Philippe Timmermans
Fifteen patients were included, with slight male predominance (9 men vs. 6 women). Four of them had a significant cardiac history, mostly supraventricular arrhythmia, but one patient had undergone coronary artery bypass surgery. Most NET’s originated from the midgut (13 patients – 87%), in the others the primary location remained unknown despite extensive medical imaging. Thirteen patients developed liver metastases, the two remaining patients had metastatic ovarian disease or extensive retroperitoneal lymph node invasion. Serum chromogranin levels at the time of NET diagnosis varied from nearly normal (239 µg/L) to extremely elevated (96,000 µg/L). Initial 5-hydroxyindoleacetic acid (5-HIAA), a metabolite of serotonin, in a 24-h urine collection was slightly or substantially elevated in all patients (minimum 10 mg, maximum 265 mg, median 96 mg, normal <9.0 mg) (Table 1).