TY - JOUR A1 - Chumak, Tetyana A1 - Rüttiger, Lukas A1 - Lee, Sze Chim A1 - Campanelli, Dario A1 - Zuccotti, Annalisa A1 - Singer, Wibke A1 - Popelář, Jiří A1 - Gutsche, Katja A1 - Geisler, Hyun-Soon A1 - Schraven, Sebastian Philipp A1 - Jaumann, Mirko A1 - Panford-Walsh, Rama A1 - Hu, Jing A1 - Schimmang, Thomas A1 - Zimmermann, Ulrike A1 - Syka, Josef A1 - Knipper, Marlies T1 - BDNF in Lower Brain Parts Modifies Auditory Fiber Activity to Gain Fidelity but Increases the Risk for Generation of Central Noise After Injury JF - Molecular Neurobiology N2 - For all sensory organs, the establishment of spatial and temporal cortical resolution is assumed to be initiated by the first sensory experience and a BDNF-dependent increase in intracortical inhibition. To address the potential of cortical BDNF for sound processing, we used mice with a conditional deletion of BDNF in which Cre expression was under the control of the Pax2 or TrkC promoter. BDNF deletion profiles between these mice differ in the organ of Corti (BDNF \(^{Pax2}\) -KO) versus the auditory cortex and hippocampus (BDNF \(^{TrkC}\) -KO). We demonstrate that BDNF \(^{Pax2}\) -KO but not BDNF \(^{TrkC}\) -KO mice exhibit reduced sound-evoked suprathreshold ABR waves at the level of the auditory nerve (wave I) and inferior colliculus (IC) (wave IV), indicating that BDNF in lower brain regions but not in the auditory cortex improves sound sensitivity during hearing onset. Extracellular recording of IC neurons of BDNF \(^{Pax2}\) mutant mice revealed that the reduced sensitivity of auditory fibers in these mice went hand in hand with elevated thresholds, reduced dynamic range, prolonged latency, and increased inhibitory strength in IC neurons. Reduced parvalbumin-positive contacts were found in the ascending auditory circuit, including the auditory cortex and hippocampus of BDNF \(^{Pax2}\) -KO, but not of BDNF \(^{TrkC}\) -KO mice. Also, BDNF \(^{Pax2}\) -WT but not BDNF \(^{Pax2}\) -KO mice did lose basal inhibitory strength in IC neurons after acoustic trauma. These findings suggest that BDNF in the lower parts of the auditory system drives auditory fidelity along the entire ascending pathway up to the cortex by increasing inhibitory strength in behaviorally relevant frequency regions. Fidelity and inhibitory strength can be lost following auditory nerve injury leading to diminished sensory outcome and increased central noise. KW - Inner hair cell KW - Neurotropathic Factor KW - Hearing-loss KW - Alzheimers-disease KW - low-threshold fibers KW - cochlear nucleus neurons KW - Frequency-response areas KW - Inferior colliculus KW - Environmental enrichment KW - Synaptic plasticity KW - Cortical plasticity KW - BDNF KW - Central hyperactivity KW - High-spontaneous rate KW - Homeostatic plasticity KW - Sound detection threshold Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187341 VL - 53 IS - 8 ER - TY - JOUR A1 - Wagner, Martin A1 - Ashby, Damien R. A1 - Kurtz, Caroline A1 - Alam, Ahsan A1 - Busbridge, Mark A1 - Raff, Ulrike A1 - Zimmermann, Josef A1 - Heuschmann, Peter U. A1 - Wanner, Christoph A1 - Schramm, Lothar T1 - Hepcidin-25 in diabetic chronic kidney disease is predictive for mortality and progression to end stage renal disease JF - PLoS One N2 - Background Anemia is common and is associated with impaired clinical outcomes in diabetic chronic kidney disease (CKD). It may be explained by reduced erythropoietin (EPO) synthesis, but recent data suggest that EPO-resistance and diminished iron availability due to inflammation contribute significantly. In this cohort study, we evaluated the impact of hepcidin-25—the key hormone of iron-metabolism—on clinical outcomes in diabetic patients with CKD along with endogenous EPO levels. Methods 249 diabetic patients with CKD of any stage, excluding end-stage renal disease (ESRD), were enrolled (2003–2005), if they were not on EPO-stimulating agent and iron therapy. Hepcidin-25 levels were measured by radioimmunoassay. The association of hepcidin-25 at baseline with clinical variables was investigated using linear regression models. All-cause mortality and a composite endpoint of CKD progression (ESRD or doubling of serum creatinine) were analyzed by Cox proportional hazards models. Results Patients (age 67 yrs, 53% male, GFR 51 ml/min, hemoglobin 131 g/L, EPO 13.5 U/L, hepcidin-25 62.0 ng/ml) were followed for a median time of 4.2 yrs. Forty-nine patients died (19.7%) and forty (16.1%) patients reached the composite endpoint. Elevated hepcidin levels were independently associated with higher ferritin-levels, lower EPO-levels and impaired kidney function (all p<0.05). Hepcidin was related to mortality, along with its interaction with EPO, older age, greater proteinuria and elevated CRP (all p<0.05). Hepcidin was also predictive for progression of CKD, aside from baseline GFR, proteinuria, low albumin- and hemoglobin-levels and a history of CVD (all p<0.05). Conclusions We found hepcidin-25 to be associated with EPO and impaired kidney function in diabetic CKD. Elevated hepcidin-25 and EPO-levels were independent predictors of mortality, while hepcidin-25 was also predictive for progression of CKD. Both hepcidin-25 and EPO may represent important prognostic factors of clinical outcome and have the potential to further define “high risk” populations in CKD. KW - diabetes mellitus KW - inflammation KW - type 2 diabetes KW - hemoglobin KW - chronic kidney disease KW - anemia KW - ferritin KW - proteinuria Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-125514 VL - 10 IS - 4 ER - TY - JOUR A1 - Groß, Uwe A1 - Amuzu, Sylvarius K. A1 - de Ciman, Ring A1 - Kassimova, Iparkhan A1 - Groß, Lisa A1 - Rabsch, Wolfgang A1 - Rosenberg, Ulrike A1 - Schulze, Marco A1 - Stich, August A1 - Zimmermann, Ortrud T1 - Bacteremia and Antimicrobial Drug Resistance over Time, Ghana JF - Emerging Infectious Diseases N2 - Bacterial distribution and antimicrobial drug resistance were monitored in patients with bacterial bloodstream infections in rural hospitals in Ghana. In 2001-2002 and in 2009, Salmonella enterica serovar Typhi was the most prevalent pathogen. Although most S. enterica serovar Typhi isolates were chloramphenicol resistant, all isolates tested were susceptible to ciprofloxacin. KW - Typhoid-fever KW - Children KW - Surveillance KW - Kenya Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133805 N1 - All material published in Emerging Infectious Diseases is in the public domain and may be used and reprinted without special permission; proper citation, however, is required. VL - 17 IS - 10 ER -