ArticleRedox report : communications in free radical research2014
Association of plasma ortho-tyrosine/para-tyrosine ratio with responsiveness of erythropoiesis-stimulating agent in dialyzed patients.
Article in Redox report : communications in free radical research, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT03278730 (Phase 2 Single Center, Randomized, Placebo-controlled, Double-blind, Parallel Group Study to Evaluate Efficacy of Para-Tyrosine Supplementation on the Survival and Clinical Outcome in Patients With Sepsis), which is not on this map. Cited by 8 papers.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Phase 2 Single Center, Randomized, Placebo-controlled, Double-blind, Parallel Group Study to Evaluate Efficacy of Para-Tyrosine Supplementation on the Survival and Clinical Outcome in Patients With Sepsis
Who cites it
8 citing papers in PubMed, 11 citations in OpenAlex.
- The Impact of SGLT-2 Inhibitors on Hydroxyl Radical Markers and Diabetic Neuropathy: A Short-Term Clinical Study.Antioxidants (Basel, Switzerland) · 2025Article
- The Common Single Cause of Chronic Multi-Hormonal Resistance in Oxidative Stress.Antioxidants (Basel, Switzerland) · 2022Review
- Article
- Early responsiveness to continuous erythropoietin receptor activator predicts renal prognosis and is determined by a novel antioxidative marker in non-dialysis chronic kidney disease: a prospective, observational, single-center study.Clinical and experimental nephrology · 2020Observational
- Epoetin beta pegol, but not recombinant erythropoietin, retains its hematopoietic effect in vivo in the presence of the sialic acid-metabolizing enzyme sialidase.International journal of hematology · 2016Article
- Role of Tyrosine Isomers in Acute and Chronic Diseases Leading to Oxidative Stress - A Review.Current medicinal chemistry · 2016Review
- Tyrosine isomers and hormonal signaling: A possible role for the hydroxyl free radical in insulin resistance.World journal of diabetes · 2015Review
- Insulin Therapy of Nondiabetic Septic Patients Is Predicted by para-Tyrosine/Phenylalanine Ratio and by Hydroxyl Radical-Derived Products of Phenylalanine.Oxidative medicine and cellular longevity · 2015Article
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PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
8 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Objectives Patients with end-stage renal failure (ESRF) treated with erythropoiesis-stimulating agents (ESAs) are often ESA-hyporesponsive associated with free radical production. Hydroxyl free radical converts phenylalanine into ortho-tyrosine, while physiological isomer para-tyrosine is formed enzymatically, mainly in the kidney. Production of 'para-tyrosine' is decreased in ESRF and it can be replaced by ortho-tyrosine in proteins. Our aim was to study the role of tyrosines in ESA-responsiveness. Methods Four groups of volunteers were involved in our cross-sectional study: healthy volunteers (CONTR; n = 16), patients on hemodialysis without ESA-treatment (non-ESA-HD; n = 8), hemodialyzed patients with ESA-treatment (ESA-HD; n = 40), and patients on continuous peritoneal dialysis (CAPD; n = 21). Plasma ortho-, para-tyrosine, and phenylalanine levels were detected using a high performance liquid chromatography (HPLC)-method. ESA-demand was expressed by ESA-dose, ESA-dose/body weight, and erythropoietin resistance index1 (ERI1, weekly ESA-dose/body weight/hemoglobin). Results We found significantly lower para-tyrosine levels in all groups of dialyzed patients when compared with control subjects, while in contrast ortho-tyrosine levels and ortho-tyrosine/para-tyrosine ratio were comparatively significantly higher in dialyzed patients. Among groups of dialyzed patients the ortho-tyrosine level and ortho-tyrosine/para-tyrosine ratio were significantly higher in ESA-HD than in the non-ESA-HD and CAPD groups. There was a correlation between weekly ESA-dose/body weight, ERI1, and ortho-tyrosine/para-tyrosine ratio (r = 0.441, P = 0.001; r = 0.434, P = 0.001, respectively). Our most important finding was that the ortho-tyrosine/para-tyrosine ratio proved to be an independent predictor of ERI1 (β = 0.330, P = 0.016). In these multivariate regression models most of the known predictors of ESA-hyporesponsiveness were included. Discussion Our findings may suggest that elevation of the ratio of ortho-tyrosine/para-tyrosine could be responsible for decreased ESA-responsiveness in dialyzed patients.
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