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Parkinson's Disease
Published in Charles Theisler, Adjuvant Medical Care, 2023
In this case the doses were started at 240 mg/day L-dopa, 300 mg/day 5-HTP, 3 gm/ day L-tyrosine with L-dopa doses increased to 360 mg/day after seven days. In addition, the following cofactors were administered daily: (1) vitamin C 1,000 mg; (2) calcium citrate 220 mg; (3) vitamin B6 75 mg; (4) folate 400 mcg; (5) L-lysine 500 mg; (6) L-cysteine 4,500 mg; (7) selenium 400 mcg.19 The doses were modified for a period of two years.
Hepatorenal tyrosinemia/fumarylacetoacetate hydrolase deficiency
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
The deficient enzyme is on the catabolic pathway for tyrosine, and this is the cause of the hypertyrosinemia (see Figure 22.1). Fumarylacetoacetate accumulates and is converted to succinylacetoacetate and to succinylacetone. In hepatorenal tyrosinemia, concentrations of tyrosine usually range from 170 to 660 μmol/L (3–12 mg/dL).
Homeostasis of Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
TH is a mixed function oxidase that uses L-tyrosine and molecular oxygen as substrates, and L-tetrahydrobiopterin (BH4) and ferrous iron (Fe2+) as cofactors [3]. Tyrosine is one of the 20 standard amino acids used by cells to synthesize proteins. It is a nonessential amino acid with a polar side chain group. Given its natural abundance, catecholamine levels are not influenced either by changing the dietary levels of tyrosine or by its parenteral administration, even at large amounts. Because of its essential role as a cofactor in TH enzymatic activity, a deficiency in BH4 can cause systemic deficiencies of catecholamines. One example of BH4 deficiency is the development of dopamine-responsive dystonia, characterized by increased muscle tone and Parkinsonian features. This condition can be treated with carbidopa/levodopa which directly restores dopamine levels within the brain.
Predictive serum biomarkers of patients with cerebral infarction
Published in Neurological Research, 2022
Yan Kong, Yu-qing Feng, Ya-ting Lu, Shi-sui Feng, Zheng Huang, Qian-yi Wang, Hui-min Huang, Xue Ling, Zhi-heng Su, Yue Guo
Tyrosine, tyramine, and vanylglycol were enriched in the tyrosine metabolic pathway. Tyrosine is converted into tyramine and vanylglycol either directly or indirectly. Our results revealed that the levels of tyrosine, tyramine, and vanylglycol were significantly higher in the patient group than in the control group. One study indicated that tyrosine phosphatase has therapeutic potential in ischemic brain injury [23]. Based on this, we speculated that the low level of tyrosine phosphatase in the serum of patients with cerebral infarction reduces the level of tyrosine phosphorylation and increases the production of tyrosine and vanylglycol. Thus, the increases in tyrosine, tyramine, and vanylglycol due to weakened tyrosine phosphorylation may underlie the pathogenesis of cerebral infarction, and research on the development of drugs to treat cerebral infarction may focus on tyrosine phosphatase drugs.
Pharmacotherapeutic strategies for the treatment of anorexia nervosa – too much for one drug?
Published in Expert Opinion on Pharmacotherapy, 2020
Omega-3 fatty acids are important building blocks for brain development and restoring a deficiency due to malnutrition in anorexia nervosa had been hypothesized to maybe improve illness behavior such as high anxiety. Manos et al. conducted a controlled study over a 12-weeks period supplementing 2,120 mg eicosapentaenoic acid/600 mg docosohexaenoic acid daily (12 patients on active drug, 12 on placebo), but active supplementation could not be distinguished from placebo as trait anxiety decreased in both groups similarly [65]. Another recent nutritional supplement study compared the amino acid tyrosine, a precursor for dopamine, with placebo in a double-blind cross over design (19 patients, 3 weeks duration, 100 mg/kg/day) and reported improved depression ratings [66]. Overall, the benefits of nutritional supplements in treatment for anorexia nervosa remain uncertain and the small study sizes have been prone to error.
Distortion product otoacoustic emission sensitivity to different solvents in a population of industrial painters
Published in International Journal of Audiology, 2020
Renata Sisto, Luigi Cerini, Filippo Sanjust, Damiano Carbonari, Monica Gherardi, Andrea Gordiani, Nunziata L’Episcopo, Enrico Paci, Daniela Pigini, Giovanna Tranfo, Arturo Moleti
The oxidative stress and the nitrosative stress are recognised to cause many acute and chronic diseases and even of the physiological aging process. The oxidation process involve DNA, RNA, lipids and proteins. In the proteins usually this process implies the introduction of functional groups that could alter the protein function and metabolism. The tyrosine is an amino acid present in the most part of the proteins. This amino acid is slightly hydrophilic due to the aromatic benzene ring that transport a hydroxyl group. One of the most important biomarker of the protein oxidation is the 3 Nitrotyrosine (3NO2tyrosine), an oxidation product of the tyrosine, that is produced in the reaction of NO or of the NO3 and that represents a damage on proteins and amino acids (Bandookwala et al. 2019). In this paper, the concentration of tyrosine and of its oxidation product 3NO2tyrosine were measured and compared at the beginning and the end of the work-shift. The methylation product of the cytidine, 5-methylcytidine, was also quantified as a measure of the damage to the RNA. The 5-methylcytidine is one of the epigenetic marks of DNA and RNA, and aberrant levels of this modified nucleoside were found to be associated with various cancers (Guo et al. 2018).