TY  - CHAP
A1  - Henze, Andrea
A1  - Raila, Jens
A1  - Scholze, Alexandra
A1  - Schweigert, Florian J.
A1  - Tepel, Martin
T1  - Administration of N-Acetylcyteine causes beneficial posttranslationalmodifications of transthyretin in hemodialysis patients
T2  - Nephrology, dialysis, transplantation
Y1  - 2013
SN  - 0931-0509
VL  - 28
IS  - 2
SP  - 164
EP  - 164
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - CHAP
A1  - Hocher, Berthold
A1  - Armbruster, Franz Paul
A1  - Scholze, Alexandra
A1  - Marckmann, Peter
A1  - Reichetzeder, Christoph
A1  - Roth, Heinz Jürgen
A1  - Tepel, Martin
T1  - Non-oxidized, biological active parathyroid hormone determines motality in hemodialsysis patients
T2  - Nephrology, dialysis, transplantation
Y1  - 2013
SN  - 0931-0509
VL  - 28
SP  - 33
EP  - 33
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Henze, Andrea
A1  - Raila, Jens
A1  - Scholze, Alexandra
A1  - Zidek, Walter
A1  - Tepel, Martin
A1  - Schweigert, Florian J.
T1  - Does N-Acetylcysteine modulate post-translational modifications of transthyretin in hemodialysis patients?
JF  - Antioxidants & redox signaling
N2  - It is assumed that effects of the thiol antioxidant N-acetylcysteine (NAC) are mediated by interaction with protein-associated cysteine residues, however, information on protein level in vivo are missing. Therefore, we analyzed NAC-induced modifications of the protein transthyretin (TTR) in plasma of hemodialysis patients in a randomized, placebo-controlled study. TTR was selected due to its low molecular weight and the free cysteine residue in the polypeptide chain, which is known to be extensively modified by formation of mixed disulfides. The intravenous application of NAC during a hemodialysis session resulted in a substantial increase of native TTR from median 15% (range 8.8%-30%) to median 40% (37-50) and reduction of S-cysteinylated TTR [51% (44-60) vs. 6.6% (2.4-10)]. Additionally the pronounced formation of a TTR-NAC adduct was detected. However, all these modifications seemed to be reversible. Additionally, in vitro incubation of plasma with NAC confirmed the in vivo results and indicated that changes in post-translational modification pattern of TTR were a function of NAC concentration. Based on these observations and the essential metabolic and biochemical role of protein-associated cysteine residues we hypothesize that the interaction of NAC with proteins may explain altered protein functions due to modification of cysteine residues. Antioxid. Redox Signal. 19, 1166-1172.
Y1  - 2013
U6  - https://doi.org/10.1089/ars.2012.5125
SN  - 1523-0864
VL  - 19
IS  - 11
SP  - 1166
EP  - 1172
PB  - Liebert
CY  - New Rochelle
ER  - 
TY  - JOUR
A1  - Tepel, Martin
A1  - Armbruster, Franz Paul
A1  - Groen, Hans Juergen
A1  - Scholze, Alexandra
A1  - Reichetzeder, Christoph
A1  - Roth, Heinz Jürgen
A1  - Hocher, Berthold
T1  - Nonoxidized, biologically active parathyroid hormone determines mortality in hemodialysis patients
JF  - The journal of clinical endocrinology & metabolism
N2  - Background: It was shown that nonoxidized PTH (n-oxPTH) is bioactive, whereas the oxidation of PTH results in a loss of biological activity.
 Methods: In this study we analyzed the association of n-oxPTH on mortality in hemodialysis patients using a recently developed assay system.
 Results: Hemodialysis patients (224 men, 116 women) had a median age of 66 years. One hundred seventy patients (50%) died during the follow-up period of 5 years. Median n-oxPTH levels were higher in survivors (7.2 ng/L) compared with deceased patients (5.0 ng/L; P = .002). Survival analysis showed an increased survival in the highest n-oxPTH tertile compared with the lowest n-oxPTH tertile (chi(2), 14.3; P = 0008). Median survival was 1702 days in the highest n-oxPTH tertile, whereas it was only 453 days in the lowest n-oxPTH tertile. Multivariable-adjusted Cox regression showed that higher age increased odds for death, whereas higher n-oxPTH reduced the odds for death. Another model analyzing a subgroup of patients with intact PTH (iPTH) concentrations at baseline above the upper normal range of the iPTH assay (70 ng/L) revealed that mortality in this subgroup was associated with oxidized PTH but not with n-oxPTH levels.
 Conclusions: The predictive power of n-oxPTH and iPTH on the mortality of hemodialysis patients differs substantially. Measurements of n-oxPTH may reflect the hormone status more precisely. The iPTH-associated mortality is most likely describing oxidative stress-related mortality.
Y1  - 2013
U6  - https://doi.org/10.1210/jc.2013-2139
SN  - 0021-972X
SN  - 1945-7197
VL  - 98
IS  - 12
SP  - 4744
EP  - 4751
PB  - Endocrine Society
CY  - Chevy Chase
ER  -