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Dimitrios Tsikas
Hannover Medical School
EndocrinologyChemistryChromatographyNitric oxideBiochemistry
391Publications
47H-index
10.4kCitations
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Publications 386
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#1Ashleigh Craig (NWU: North-West University)
#2Catharina M. C. Mels (NWU: North-West University)H-Index: 9
Last. Ruan Kruger (NWU: North-West University)H-Index: 10
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Nitric oxide plays an important role in maintaining endothelial function, while increased oxidative stress may lead to nitric oxide inactivation and cardiovascular disease. If nitric oxide biosynthesis/bioavailability is already suppressed early in life, it may potentially predispose an individual to the early development of cardiovascular disease. We therefore aimed to identify differences in nitric oxide-related markers (urinary nitrate, nitrite and the nitrate-to-nitrite ratio (UNOxR)) betwee...
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Proteinic arginine dimethylation (PADiMe) is a major post-translational modification. Proteolysis of asymmetric and symmetric PADiMe products releases asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA), respectively, two endogenous atherogenic substances. SDMA, ADMA, and its major metabolite dimethylamine (DMA) are eliminated by the kidney. The urinary concentrations of DMA+ADMA, SDMA, and DMA+ADMA+SDMA are useful measures of the whole-body asymmetric and symmetric PADiMe, ...
1 CitationsSource
#1Manuela Yepes-Calderón (UMCG: University Medical Center Groningen)
#1Manuela Yepes-Calderón (UMCG: University Medical Center Groningen)
Last. Stephan J. L. Bakker (UMCG: University Medical Center Groningen)H-Index: 68
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BACKGROUND: In renal transplant recipients (RTRs), cardiovascular mortality is the most common cause of long-term renal graft loss. Oxidative stress (OS) has been associated with cardiovascular disease and is known to be enhanced in RTRs. We aimed to prospectively investigate whether the concentration of the OS biomarker malondialdehyde (MDA) is associated with long-term risk of cardiovascular mortality in a large cohort of RTRs. METHODS: The plasma MDA concentration was measured using the thiob...
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#1Dimitrios Tsikas (MHH: Hannover Medical School)H-Index: 47
#2Alexander Bollenbach (MHH: Hannover Medical School)H-Index: 4
Last. Björn Redfors (Sahlgrenska University Hospital)H-Index: 20
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Low L-homoarginine (hArg) concentrations in human blood and urine are associated with renal and cardiovascular morbidity and mortality, yet the underlying mechanisms and the biological activities of hArg are elusive. In humans and rats, hArg is metabolized to l-lysine. The aim of the present work was to study hArg metabolism to agmatine (Agm) and homoagmatine (hAgm) in the anesthetized rat. Using a newly developed and validated GC–MS method and a newly synthesized and structurally characterized ...
1 CitationsSource
#1Olga Begou (A.U.Th.: Aristotle University of Thessaloniki)H-Index: 3
#2Kathrin Drabert (MHH: Hannover Medical School)
Last. Dimitrios Tsikas (MHH: Hannover Medical School)H-Index: 47
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Abstract Acetazolamide (molecular mass (MM), 222) belongs to the class of sulfonamides (R-SO2-NH2) and is one of the strongest pharmacological inhibitors of carbonic anhydrase activity. Acetazolamide is excreted unchanged in the urine. Here, we report on the development, validation and biomedical application of a stable-isotope dilution GC-MS method for the reliable quantitative determination of acetazolamide in human urine. The method is based on evaporation to dryness of 50 μμL urine aliquots,...
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#1Erik Hanff (MHH: Hannover Medical School)H-Index: 10
#2Alexander Bollenbach (MHH: Hannover Medical School)H-Index: 4
Last. Dimitrios Tsikas (MHH: Hannover Medical School)H-Index: 47
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Gas chromatography–mass spectrometry (GC–MS) methods were developed, validated and used to measure serum spermidine (SPD) and putrescine (PUT) in 9 seropositive Helicobacter pylori (Hp +) and 18 seronegative Helicobacter pylori (Hp −) subjects (31–105 years). Homoarginine (hArg) was also measured by GC–MS. There were no statistical differences (unpaired t test) between the Hp + and Hp − subjects with respect to the serum concentrations of SPD (67.6 ± 40.3 vs. 93.7 ± 37.7 nM, P = 0.109), PUT (220...
2 CitationsSource
Attention deficit hyperactivity disorder (ADHD) is a common pediatric psychiatric disorder, frequently treated with methylphenidate (MPH). Recently, MPH’s cardiovascular safety has been questioned by observational studies describing an increased cardiovascular risk in adults and blood pressure alterations in children. We considered members of the L-arginine (Arg)/nitric oxide (NO) pathway as possible early cardiovascular risk factors in pediatric ADHD children. They include the NO metabolites, n...
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#1Alexander Bollenbach (MHH: Hannover Medical School)H-Index: 4
#2Dimitrios Tsikas (MHH: Hannover Medical School)H-Index: 47
Last. Anne Jörns (MHH: Hannover Medical School)H-Index: 25
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The LEW.1AR1-iddm rat is an animal model of human type 1 diabetes (T1D). We determined by GC–MS the extent of asymmetric dimethylation (prADMA) and citrullination (prCit) of l-arginine residues in organ proteins (pr) of normoglycaemic control (ngCo, n = 6), acutely diabetic (acT1D, n = 6), chronically diabetic (chT1D, n = 4), and cured (cuT1D, n = 4) rats after anti-TCR/anti-TNF-α therapy. Pancreatic prCit and prADMA did not differ between the groups but were correlated (r = 0.728, P = 0.0003, n...
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#1Stefan ÜckertH-Index: 30
#2Armin J. BeckerH-Index: 24
Last. Markus A. KuczykH-Index: 43
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#1Erik Hanff (MHH: Hannover Medical School)H-Index: 10
#2M. Y. Said (UMCG: University Medical Center Groningen)H-Index: 1
Last. Dimitrios Tsikas (MHH: Hannover Medical School)H-Index: 47
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l-Arginine:glycine amidinotransferase (AGAT) is the main producer of the creatine precursor, guanidinoacetate (GAA), and l-homoarginine (hArg). We and others previously reported lower levels of circulating and urinary hArg in renal transplant recipients (RTR) compared to healthy subjects. In adults, hArg emerged as a novel risk factor for renal and cardiovascular adverse outcome. Urinary GAA was found to be lower in children and adolescents with kidney transplants compared to healthy controls. W...
1 CitationsSource
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