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Nils Peters - Top 30 Publications

Early start of DOAC after ischemic stroke: Risk of intracranial hemorrhage and recurrent events.

In patients with recent acute ischemic stroke (AIS) and atrial fibrillation, we assessed the starting time of direct, non-vitamin K antagonist oral anticoagulants (DOACs) for secondary prevention, the rate of intracranial hemorrhage (ICH), and recurrent ischemic events during follow-up.

Frequency and Determinants of Adherence to Oral Anticoagulants in Stroke Patients with Atrial Fibrillation in Clinical Practice.

Vitamin K antagonists (VKAs) and non-VKA oral anticoagulants (NOACs) are beneficial in patients with stroke and atrial fibrillation (AF). However, little is known about frequency and determinants of adherence to NOACs/VKAs in clinical practice.

Feasibility of rapid measurement of Rivaroxaban plasma levels in patients with acute stroke.

Plasma levels of Rivaroxaban (RivLev) might be useful to guide therapeutic decisions in patients with acute stroke under Rivaroxaban. A prerequisite for the potential clinical usefulness is their rapid availability in emergency situations. Single-center explorative analysis from the Novel-Oral-Anticoagulants-in-Stroke-Patients-registry (NOACISP, We included consecutive patients with acute ischemic or hemorrhagic stroke under Rivaroxaban (last intake <48 h) in which RivLev determined by an automated anti-factor Xa-based chromogenic assay (Hyphen-Biomed, France) are available. Primary endpoint was the turnaround time (TAT), defined as time from registration of the blood sample in the lab to first result published. Furthermore, we studied, whether TAT is influenced by (1) on- and off-hour-measurements and (2) early versus later patient arrival (cut-off: 270 min after symptom onset). Thirty-eight patients met the eligibility criteria (mean age 77 years, 44 % female). TAT was 34 min (IQR 29-65 min). TATs were similar for on- (n = 14; median 34 min; IQR 30-56 min) and off-hours-TATs (n = 24; median 35 min; IQR 29-75 min) as well as for early (n = 16; median 33 min; IQR 30-40 min) and late patient arrival (n = 22, median 34 min, IQR 28-58 min; all nonsignificant.). Taking into account RivLev in the decision process about the use of intravenous thrombolysis, three patients received intravenous thrombolysis on an individualized basis, none of them with bleeding complications. Emergency measurement of RivLev among patients with acute stroke is available within a median of 34 min and therefore feasible for ED use. Due to the rapid availability, further research to evaluate the role of RivLev in order to guide acute treatment decisions is warranted.

Granulomatous encephalitis: protothecosis excluded?

Radioablation of liver malignancies with interstitial high-dose-rate brachytherapy : Complications and risk factors.

To evaluate complications and identify risk factors for adverse events in patients undergoing high-dose-rate interstitial brachytherapy (iBT).

Intravenous Thrombolysis in Patients Dependent on the Daily Help of Others Before Stroke.

We compared outcome and complications in patients with stroke treated with intravenous thrombolysis (IVT) who could not live alone without help of another person before stroke (dependent patients) versus independent ones.

Identification of Inflammatory, Metabolic, and Cell Survival Pathways Contributing to Cerebral Small Vessel Disease by Postmortem Gene Expression Microarray.

Cerebral small-vessel disease (SVD) is characterized by periventricular white matter (WM) changes and general brain atrophy. SVD is prevalent in elderly individuals and is frequently associated with the development of vascular dementia (VaD). Studies of the molecular basis of SVD are sparse. We have to gain further insight into the pathogenic mechanisms of SVD. Therefore, we compared gene expression patterns in the brains of SVD and control patients, in order to identify cellular pathways changed in diseased brains. We compared the expression of mRNA transcripts in postmortem, macroscopically normal-appearing human brain tissues isolated from frontal, temporal and occipital cortical and subcortical regions in 5 SVD and 5 non-SVD control patients. Significant expression changes were determined by fold change F>1.2 in either direction, and p<0.05. We identified 228 genes differentially expressed in cortex (89 up-, 139 down-regulated) and 555 genes in WM (223 up-, 332 down-regulated) in SVD patients. Pathway analyses revealed that upregulated genes were associated with inflammation and apoptosis in WM, suggesting active cell death. Downregulated genes were associated with coagulation and fatty and amino acids metabolisms. In the cortex, down-regulated genes were principally associated with neuronal functions. Our data revealed widespread changes in the transcriptome profiles in the cortex and WM of human SVD brains, with a predominance of changes in WM. We provide for the first time a comprehensive view of the molecular alterations in human SVD brains that seem to contribute to the neuropathogenesis of SVD.

Serum Neurofilament Light Chain Levels Are Associated with Clinical Characteristics and Outcome in Patients with Cervical Artery Dissection.

Serum neurofilament light chain (sNfL) levels represent a promising marker of neuroaxonal injury. They are elevated in several neurological conditions, but their importance in cerebrovascular diseases remains unclear. In a proof of concept study, we compared sNfL levels with clinical characteristics and outcome in patients with cervical artery dissection (CeAD).

Recanalization therapies in acute ischemic stroke patients: impact of prior treatment with novel oral anticoagulants on bleeding complications and outcome.

We explored the safety of intravenous thrombolysis (IVT) or intra-arterial treatment (IAT) in patients with ischemic stroke on non-vitamin K antagonist oral anticoagulants (NOACs, last intake <48 hours) in comparison with patients (1) taking vitamin K antagonists (VKAs) or (2) without previous anticoagulation (no-OAC).

Long-term observations in asymmetric immune-mediated neuropathy with vagus hypertrophy using ultrasound of the nerves.

Ischemic brain lesions after carotid artery stenting increase future cerebrovascular risk.

Brain lesions on diffusion-weighted imaging (DWI) are frequently found after carotid artery stenting (CAS), but their clinical relevance remains unclear.

Neurological picture. Vagal hypertrophy in immune-mediated neuropathy visualised with high-resolution ultrasound (HR-US).

In vitro efficacy and release study with anti-inflammatory drugs incorporated in adhesive transdermal drug delivery systems.

The topical application of two different anti-inflammatory extracts incorporated in adhesive transdermal drug delivery systems (TDDSs) was investigated. Therefore, anti-inflammatory properties and percutaneous absorption behavior of adhesive TDDSs were characterized in vitro conducting experiments with a dermatologically relevant human skin model. Anti-inflammatory efficacy against UV irradiation of both TDDSs was determined in vitro with EpiDerm™. The reduction of the release of proinflammatory cytokines by topically applied TDDSs was compared with the reduction during the presence of the specific cyclooxygenase inhibitor diclofenac in the culture medium. A similar anti-inflammatory efficacy of the topically applied TDDSs in comparison with the use of diclofenac in the culture medium should be achieved. Furthermore, percutaneous absorption in efficacy tests was compared with percutaneous absorption in diffusion studies with porcine cadaver skin. Both the topically applied TDDSs showed a significant anti-inflammatory activity. Permeation coefficients through the stratum corneum and the epidermis gained from the release studies on porcine cadaver skin (Magnolia: 2.23·10(-5) cm/h, licorice: 4.68·10(-6) cm/h) were approximately five times lower than the permeation coefficients obtained with the EpiDerm™ skin model (Magnolia: 9.48·10(-5) cm/h, licorice: 24.0·10(-6) cm/h). Therefore, an adjustment of drug doses during experiments with the EpiDerm™ skin model because of weaker skin barrier properties should be considered.

IV thrombolysis and renal function.

To investigate the association of renal impairment on functional outcome and complications in stroke patients treated with IV thrombolysis (IVT).

Long-term outcome in stroke patients treated with IV thrombolysis.

Data on long-term outcome after IV thrombolysis (IVT) are sparse. Our goals were to 1) estimate annual survival, and 2) evaluate determinants for an unfavorable long-term outcome after IVT for stroke.

Education modifies the relation of vascular pathology to cognitive function: cognitive reserve in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

A clinical impact of cognitive reserve (CR) has been demonstrated in Alzheimer's disease, whereas its role in vascular cognitive impairment (VCI) is largely unknown. In this study, we investigated the impact of CR in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a genetic variant of pure VCI. A total of 247 NOTCH3 mutation carriers from a two-center study were investigated using detailed neuropsychological and neuroimaging protocols. CR was operationalized as years of formal education. Brain pathology was assessed by MRI using normalized brain volume and lacunar lesion volume as proxies. Multivariate analyses were done for each structural measure with scores of processing speed, executive function, and memory as dependent variables. Additional linear regression models were conducted with interaction terms for education × brain volume and education × lacunar lesion volume. Education had an independent impact on cognitive performance in subjects with mild and moderate degrees of brain pathology, whereas there was no significant influence of education on cognition in patients with severe MRI changes. This interaction was found for processing speed, the cognitive domain most impaired in our patients. Our findings demonstrate an interaction of education and brain pathology in regard to cognitive impairment: the effect of education seems most pronounced in early disease stages but may ultimately be overwhelmed by the pathological changes. The results extend the concept of CR to VCI.

Pontine and extrapontine myolinolysis associated with hypernatraemia.

DNA methylation regulates lineage-specifying genes in primary lymphatic and blood endothelial cells.

During embryonic development, the lymphatic system emerges by transdifferentiation from the cardinal vein. Although lymphatic and blood vasculature share a close molecular and developmental relationship, they display distinct features and functions. However, even after terminal differentiation, transitions between blood endothelial cells (BEC) and lymphatic endothelial cells (LEC) have been reported. Since phenotypic plasticity and cellular differentiation processes frequently involve epigenetic mechanisms, we hypothesized that DNA methylation might play a role in regulating cell type-specific expression in endothelial cells. By analyzing global gene expression and methylation patterns of primary human dermal LEC and BEC, we identified a highly significant set of genes, which were differentially methylated and expressed. Pathway analyses of the differentially methylated and upregulated genes in LEC revealed involvement in developmental and transdifferentiation processes. We further identified a set of novel genes, which might be implicated in regulating BEC-LEC plasticity and could serve as therapeutic targets and/or biomarkers in vascular diseases associated with alterations in the endothelial phenotype.

Strategic role of frontal white matter tracts in vascular cognitive impairment: a voxel-based lesion-symptom mapping study in CADASIL.

Cerebral small vessel disease is the most common cause of vascular cognitive impairment. It typically manifests with lacunar infarcts and ischaemic white matter lesions. However, little is known about how these lesions relate to the cognitive symptoms. Previous studies have found a poor correlation between the burden of ischaemic lesions and cognitive symptoms, thus leaving much of the variance in cognitive performance unexplained. The objective of the current study was to investigate the relationship between the location of subcortical ischaemic lesions and cognitive symptoms in small vessel disease. We applied a voxel-based lesion-symptom mapping approach to data from 215 patients with CADASIL, a genetically defined small vessel disease with mutations in the NOTCH3 gene. All patients were examined by magnetic resonance imaging and comprehensive neuropsychological testing. Lacunar lesions and white matter lesions were segmented on three-dimensional T(1) and fluid-attenuated inversion recovery sequences, respectively. One hundred and forty-five subjects had a total of 854 lacunar lesions (range 1-13 per individual). The normalized volume of white matter hyperintensities ranged from 0.0425% to 21.5% of the intracranial cavity. Significant clusters for cognitive performance were detected for both lacunar lesions and white matter hyperintensities. The most prominent results were obtained on a compound score for processing speed, the predominantly affected cognitive domain in this group of patients. Strategic locations included the anterior parts of the thalamus, the genu and anterior limb of the internal capsule, the anterior corona radiata and the genu of the corpus callosum. By combining the lesion-symptom mapping data with information from a probabilistic white matter atlas we found that the majority of the processing speed clusters projected on the anterior thalamic radiation and the forceps minor. In multivariate models that included demographic parameters, brain atrophy and the volume of ischaemic lesions, regional volumes of lacunar lesions and white matter hyperintensities in the anterior thalamic radiation predicted performance in processing speed tasks, whereas there was no independent contribution of the global volume of ischaemic lesions. These observations emphasize the importance of lesion location for both lacunar and ischaemic white matter lesions. Our findings further highlight the anterior thalamic radiation as a major anatomical structure impacting on processing speed. Together these findings provide strong support for a central role of frontal-subcortical circuits in cerebral small vessel disease and vascular cognitive impairment.

Co-aggregate formation of CADASIL-mutant NOTCH3: a single-particle analysis.

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is the most common monogenic cause of stroke and vascular dementia. Accumulation and deposition of the NOTCH3 (N3) extracellular domain in small blood vessels has been recognized as a central pathological feature of the disease. Recent experiments suggested enhanced formation of higher order multimers for mutant N3 compared with wild-type (WT). However, the mechanisms and consequences of N3 multimerization are still poorly understood, in part because of the lack of an appropriate in vitro aggregation assay. We therefore developed and validated a robust assay based on recombinant N3 fragments purified from cell culture supernatants. Using single-molecule analysis techniques such as scanning for intensely fluorescent targets and single-particle fluorescence resonance energy transfer, we show that spontaneous aggregation is limited to CADASIL-mutant N3, recapitulating a central aspect of CADASIL pathology in vitro. N3 aggregation requires no co-factor and is facilitated by sulfhydryl crosslinking. Although WT N3 does not exhibit multimerization itself, it can participate in aggregates of mutant N3. Furthermore, we demonstrate that thrombospondin-2, a known interaction partner of N3, co-aggregates with mutant N3. Sequestration of WT N3 and other proteins into aggregates represents a potentially important disease mechanism. These findings in combination with a new assay for single-molecule aggregation analysis provide novel opportunities for the development of therapeutic strategies.

Treatment of hepatic metastases of breast cancer with CT-guided interstitial brachytherapy - a phase II-study.

The aim of the study was the evaluation of feasibility, safety and effectiveness of interstitial brachytherapy for the treatment of hepatic metastases of breast cancer.

Valsalva-maneuver induced recurrent transient bilateral visual loss.

Detection of type II endoleak after endovascular aortic repair: comparison between magnetic resonance angiography and blood-pool contrast agent and dual-phase computed tomography angiography.

This prospective study was designed to assess the diagnostic value of magnetic resonance angiography (MRA) with blood-pool contrast agent (gadofosveset) in the detection of type-II endoleak after endovascular aortic repair (EVAR).

Aging and chronic sun exposure cause distinct epigenetic changes in human skin.

Epigenetic changes are widely considered to play an important role in aging, but experimental evidence to support this hypothesis has been scarce. We have used array-based analysis to determine genome-scale DNA methylation patterns from human skin samples and to investigate the effects of aging, chronic sun exposure, and tissue variation. Our results reveal a high degree of tissue specificity in the methylation patterns and also showed very little interindividual variation within tissues. Data stratification by age revealed that DNA from older individuals was characterized by a specific hypermethylation pattern affecting less than 1% of the markers analyzed. Interestingly, stratification by sun exposure produced a fundamentally different pattern with a significant trend towards hypomethylation. Our results thus identify defined age-related DNA methylation changes and suggest that these alterations might contribute to the phenotypic changes associated with skin aging.

MR-guided liver tumor ablation employing open high-field 1.0T MRI for image-guided brachytherapy.

To determine the feasibility and safety of image-guided brachytherapy employing a modified open high-field MR system.

Epileptic asystole.

Subacute herpes simplex encephalitis presenting as relapsing encephalitis.

Computed tomography-guided high-dose-rate brachytherapy in hepatocellular carcinoma: safety, efficacy, and effect on survival.

To determine the safety and efficacy of computed tomography (CT)-guided brachytherapy in hepatocellular carcinoma (HCC).

A case of Sturge-Weber syndrome with symptomatic hemiplegic migraine: clinical and multimodality imaging data during a prolonged attack.

Hemiplegic migraine (HM) in the setting of Sturge-Weber syndrome (SWS) has been previously described. Here, we report clinical and multimodal imaging data on a 21-year-old man with SWS and HM, who presented during an acute HM attack with a dense left-hemispheric syndrome (expressive aphasia and right sensorimotor hemiplegia), lasting for more than 10 days. Repeated EEGs were without evidence of status epilepticus. Consistent with previous findings in prolonged migraine aura, perfusion computed tomography demonstrated left-hemispheric hyperperfusion on day 7. 18F-FDG positron emission tomography (day 7) revealed left-hemispheric hypermetabolism. After 14 days, the patient was symptom-free and discharged home. Follow-up after 30 days showed normal neurological status. Our observation confirms and reinforces the comorbidity of SWS and HM and shows that prolonged HM attacks are associated with complex changes of both cerebral perfusion and glucose metabolism. A pathophysiological model explaining both the association between SWS/HM and the observed imaging changes is presented.

Hepatocellular carcinoma and liver cirrhosis: assessment of the liver function after Yttrium-90 radioembolization with resin microspheres or after CT-guided high-dose-rate brachytherapy.

To identify changes of liver function after single-fraction irradiation or yttrium-90 radioembolization ((90)Y-RE) of hepatocellular carcinoma associated with liver cirrhosis on the basis of laboratory data.