Ulrich Mehnert

Dr. Ulrich Mehnert


Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 September 2017 in BMC Urology
Verified
Journal Article
Open access
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LLLorenz Leitner
Lorenz Leitner
WSWilbert Sybesma
Wilbert Sybesma
Nina ChanishviliNina Chanishvili
Nina Chanishvili
MGMarina Goderdzishvili
Marina Goderdzishvili
ACArchil Chkhotua
Archil Chkhotua
Thomas M. KesslerThomas M. Kessler
Thomas M. Kessler
Urinary tract infections (UTI) are among the most prevalent microbial diseases and their financial burden on society is substantial. The continuing increase of antibiotic resistance worldwide is alarming. Thus, well-tolerated, highly effective therapeutic alternatives are urgently needed. Although there is evidence indicating that bacteriophage therapy may be effective and safe for treating UTIs, the number of investigated patients is low and there is a lack of randomized controlled trials. This study is the first randomized, placebo-controlled, double-blind trial investigating bacteriophages in UTI treatment. Patients planned for transurethral resection of the prostate are screened for UTIs and enrolled if in urine culture eligible microorganisms ≥104 colony forming units/mL are found. Patients are randomized in a double-blind fashion to the 3 study treatment arms in a 1:1:1 ratio to receive either: a) bacteriophage (i.e. commercially available Pyo bacteriophage) solution, b) placebo solution, or c) antibiotic treatment according to the antibiotic sensitivity pattern. All treatments are intended for 7 days. No antibiotic prophylaxes will be given to the double-blinded treatment arms a) and b). As common practice, the Pyo bacteriophage cocktail is subjected to periodic adaptation cycles during the study. Urinalysis, urine culture, bladder and pain diary, and IPSS questionnaire will be completed prior to and at the end of treatment (i.e. after 7 days) or at withdrawal/drop out from the study. Patients with persistent UTIs will undergo antibiotic treatment according to antibiotic sensitivity pattern. Based on the high lytic activity and the potential of resistance optimization by direct adaptation of bacteriophages, and considering the continuing increase of antibiotic resistance worldwide, bacteriophage therapy is a very promising treatment option for UTIs. Thus, our randomized controlled trial investigating bacteriophages for treating UTIs will provide essential insights into this potentially revolutionizing treatment option. This study has been registered at clinicaltrials.gov ( www.clinicaltrials.gov/ct2/show/NCT03140085 ). April 27, 2017.

13 April 2018 in BMC Medicine
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Journal Article
Open access
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MWMatthias Walter
Matthias Walter
SKStephanie C. Knüpfer
Stephanie C. Knüpfer
JCJacquelyn J. Cragg
Jacquelyn J. Cragg
LLLorenz Leitner
Lorenz Leitner
MSMarc P. Schneider
Marc P. Schneider
Thomas M. KesslerThomas M. Kessler
Thomas M. Kessler
Autonomic dysreflexia is a severe and potentially life-threatening condition in patients with spinal cord injury, as it can lead to myocardial ischemia, brain hemorrhage, or even death. Urodynamic investigation is the gold standard to assess neurogenic lower urinary tract dysfunction due to spinal cord injury and reveal crucial pathological findings, such as neurogenic detrusor overactivity. However, neurogenic detrusor overactivity and urodynamic investigation are known to be leading triggers of autonomic dysreflexia. Therefore, we aimed to determine predictors of autonomic dysreflexia in individuals with spinal cord injury during urodynamic investigation. This prospective cohort study included 300 patients with spinal cord injuries and complete datasets of continuous non-invasive cardiovascular monitoring, recorded during same session repeat urodynamic investigation. We used logistic regression to reveal predictors of autonomic dysreflexia during urodynamic investigation. We found that level of injury and presence of neurogenic detrusor overactivity were the only two independent significant predictors for autonomic dysreflexia during urodynamic investigation. A lesion at spinal segment T6 or above (odds ratio (OR) 5.5, 95% CI 3.2–9.4) compared to one at T7 or below, and presence of neurogenic detrusor overactivity (OR 2.7, 95% confidence interval (CI) 1.4–4.9) were associated with a significant increased odds of autonomic dysreflexia during urodynamic investigation. Both odds persisted after adjustment for age, sex, and completeness and stage of injury (adjusted OR (AOR) 6.6, 95% CI 3.8–11.7, and AOR 2.2, 95% CI 1.1–4.5, respectively). Further stratification by lesion level showed level-dependent significantly increased adjusted odds of autonomic dysreflexia, i.e., from C1–C4 (AOR 16.2, 95% CI 5.9–57.9) to T4–T6 (AOR 2.6, 95% CI 1.3–5.2), compared to lesions at T7 or below. In patients with neurogenic lower urinary tract dysfunction due to spinal cord injury, autonomic dysreflexia is independently predicted by lesion level and presence of neurogenic detrusor overactivity. Considering the health risks associated with autonomic dysreflexia, such as seizures, stroke, retinal bleeding, or even death, we recommend both continuous cardiovascular monitoring during urodynamic investigation in all spinal cord-injured patients with emphasis on those with cervical lesions, and appropriate neurogenic detrusor overactivity treatment to reduce the probability of potentially life-threatening complications. ClinicalTrials.gov, NCT01293110 .

13 August 2020 in BMJ Open
Verified
Journal Article
Open access
PDF file
VBVeronika Birkhäuser
Veronika Birkhäuser
MLMartina D. Liechti
Martina D. Liechti
CACollene E Anderson
Collene E Anderson
LBLucas M Bachmann
Lucas M Bachmann
SBSarah Baumann
Sarah Baumann
Thomas M. KesslerThomas M. Kessler
Thomas M. Kessler
Introduction Neurogenic lower urinary tract dysfunction (NLUTD), including neurogenic detrusor overactivity (NDO) and detrusor sphincter dyssynergia, is one of the most frequent and devastating sequelae of spinal cord injury (SCI), as it can lead to urinary incontinence and secondary damage such as renal failure. Transcutaneous tibial nerve stimulation (TTNS) is a promising, non-invasive neuromodulatory intervention that may prevent the emergence of the C-fibre evoked bladder reflexes that are thought to cause NDO. This paper presents the protocol for TTNS in acute SCI (TASCI), which will evaluate the efficacy of TTNS in preventing NDO. Furthermore, TASCI will provide insight into the mechanisms underlying TTNS, and the course of NLUTD development after SCI. Methods and analysis TASCI is a nationwide, randomised, sham-controlled, double-blind clinical trial, conducted at all four SCI centres in Switzerland. The longitudinal design includes a baseline assessment period 5–39 days after acute SCI and follow-up assessments occurring 3, 6 and 12 months after SCI. A planned 114 participants will be randomised into verum or sham TTNS groups (1:1 ratio), stratified on study centre and lower extremity motor score. TTNS is performed for 30 min/day, 5 days/week, for 6–9 weeks starting within 40 days after SCI. The primary outcome is the occurrence of NDO jeopardising the upper urinary tract at 1 year after SCI, assessed by urodynamic investigation. Secondary outcome measures assess bladder and bowel function and symptoms, sexual function, neurological structure and function, functional independence, quality of life, as well as changes in biomarkers in the urine, blood, stool and bladder tissue. Safety of TTNS is the tertiary outcome. Ethics and dissemination TASCI is approved by the Swiss Ethics Committee for Northwest/Central Switzerland, the Swiss Ethics Committee Vaud and the Swiss Ethics Committee Zürich (#2019-00074). Findings will be disseminated through peer-reviewed publications. Trial registration number NCT03965299.

5 February 2021 in BJU International
Verified
Journal Article
Closed access
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MWMatthias Walter
Matthias Walter
LLLorenz Leitner
Lorenz Leitner
CBCornelia Betschart
Cornelia Betschart
DEDaniel S. Engeler
Daniel S. Engeler
PFPatrick Freund
Patrick Freund
UMUlrich Mehnert
Ulrich Mehnert

1 January 2023 in Journal of Urology
Verified
Journal Article
Open access
MKMarko Kozomara
Marko Kozomara
VBVeronika Birkhäuser
Veronika Birkhäuser
CACollene E Anderson
Collene E Anderson
MBMirjam Bywater
Mirjam Bywater
OGOliver Gross
Oliver Gross
Thomas M. KesslerThomas M. Kessler
Thomas M. Kessler
Purpose:We aimed to provide a real-world description of neurogenic lower urinary tract dysfunction within the first year after spinal cord injury with a focus on unfavorable urodynamic para...

1 May 2019 in NeuroImage
Verified
Journal Article
Open access
MWMatthias Walter
Matthias Walter
LLLorenz Leitner
Lorenz Leitner
LMLars Michels
Lars Michels
MLMartina D. Liechti
Martina D. Liechti
PFPatrick Freund
Patrick Freund
UMUlrich Mehnert
Ulrich Mehnert
Previous functional neuroimaging studies provided evidence for a specific supraspinal network involved in lower urinary tract (LUT) control. However, data on the reliability of blood oxygenation level-dependent (BOLD) signal changes during LUT task-related functional magnetic resonance imaging (fMRI) across separate measurements are lacking. Proof of the latter is crucial to evaluate whether fMRI can be used to assess supraspinal responses to LUT treatments. Therefore, we prospectively assessed task-specific supraspinal responses from 20 healthy participants undergoing two fMRI measurements (test-retest) within 5-8 weeks. The fMRI measurements, conducted in a 3T magnetic resonance (MR) scanner, comprised a block design of repetitive bladder filling and drainage using an automated MR-compatible and MR-synchronized infusion-drainage device. Following transurethral catheterization and bladder pre-filling with body warm saline until participants perceived a persistent desire to void (START condition), fMRI was recorded during repetitive blocks (each 15 s) of INFUSION and WITHDRAWAL of 100 mL body warm saline into respectively from the bladder. BOLD signal changes were calculated for INFUSION minus START. In addition to whole brain analysis, we assessed BOLD signal changes within multiple 'a priori' region of interest (ROI), i.e. brain areas known to be involved in the LUT control from previous literature. To evaluate reliability of the fMRI results between visits, we applied different types of analyses: coefficient of variation (CV), intraclass correlation coefficient (ICC), Sørensen-Dice index, Bland-Altman method, and block-wise BOLD signal comparison. All participants completed the study without adverse events. The desire to void was rated significantly higher for INFUSION compared to START or WITHDRAWAL at both measurements without any effect of visit. At whole brain level, significant (p < 0.05, cluster corrected, k ≥ 41 voxels) BOLD signal changes were found for the contrast INFUSION compared to START in several brain areas. Overlap of activation maps from both measurements were observed in the orbitofrontal cortex, insula, ventrolateral prefrontal cortex (VLPFC), and inferior parietal lobe. The two highest ICCs, based on a ROI's mean beta weight, were 0.55 (right insular cortex) and 0.47 (VLPFC). Spatial congruency (Sørensen-Dice index) of all voxels within each ROI between measurements was highest in the insular cortex (left 0.55, right 0.44). In addition, the mean beta weight of the right insula and right VLPFC demonstrated the lowest CV and narrowest Bland and Altman 95% limits of agreement. In conclusion, the right insula and right VLPFC were revealed as the two most reliable task-specific ROIs using our automated, MR-synchronized protocol. Achieving high reliability using a viscero-sensory/interoceptive task such as repetitive bladder filling remains challenging and further endeavour is highly warranted to better understand which factors influence fMRI outcomes and finally to assess LUT treatment effects on the supraspinal level.