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265 Publications visible to you, out of a total of 265
Validating new diagnostic imaging criteria for primary progressive aphasia via anatomical likelihood estimation meta-analyses.
LIFE Adult

Abstract (Expand)

Recently, diagnostic clinical and imaging criteria for primary progressive aphasia (PPA) have been revised by an international consortium (Gorno-Tempini et al. Neurology 2011;76:1006-14). The aim of … this study was to validate the specificity of the new imaging criteria and investigate whether different imaging modalities [magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (FDG-PET)] require different diagnostic subtype-specific imaging criteria. Anatomical likelihood estimation meta-analyses were conducted for PPA subtypes across a large cohort of 396 patients: firstly, across MRI studies for each of the three PPA subtypes followed by conjunction and subtraction analyses to investigate the specificity, and, secondly, by comparing results across MRI vs. FDG-PET studies in semantic dementia and progressive nonfluent aphasia. Semantic dementia showed atrophy in temporal, fusiform, parahippocampal gyri, hippocampus, and amygdala, progressive nonfluent aphasia in left putamen, insula, middle/superior temporal, precentral, and frontal gyri, logopenic progressive aphasia in middle/superior temporal, supramarginal, and dorsal posterior cingulate gyri. Results of the disease-specific meta-analyses across MRI studies were disjunct. Similarly, atrophic and hypometabolic brain networks were regionally dissociated in both semantic dementia and progressive nonfluent aphasia. In conclusion, meta-analyses support the specificity of new diagnostic imaging criteria for PPA and suggest that they should be specified for each imaging modality separately.

Authors: S. Bisenius, J. Neumann, M. L. Schroeter

Date Published: 23rd Feb 2016

Publication Type: Not specified

Human Diseases: aphasia

Validation of a brief step-test protocol for estimation of peak oxygen uptake.
LIFE Heart

Abstract (Expand)

BACKGROUND: Physical exercise capacity has been shown to predict cardiovascular disease incidence and is increasingly measured in epidemiological studies. However, direct measurement of peak oxygen … uptake is too time consuming in large-scale studies. We therefore investigated whether a brief 3-minute step-test protocol can be used to estimate peak oxygen uptake in these settings. DESIGN AND METHODS: A group of 97 subjects performed the YMCA step test and a maximal treadmill test with continuous measurement of oxygen uptake. Correlation and linear regression analyses were used to identify VO2peak predictors obtained from the step test and to develop models for VO2peak estimation. RESULTS: The YMCA model, including the 1-minute heart beat count, predicted VO2peak with R = 0.83. A novel simplified model based on the heart rate at 45 s of recovery performed comparable (R = 0.83). However, models based on heart rate measures were only valid in subjects who completed the test according to protocol, but not in subjects who terminated prematurely. For the applicability in subjects with low exercise capacity, a new model including gas exchange analysis enabled prediction of VO2peak (R = 0.89). All models were validated in an independent sample (r = 0.86-0.91). Exercise time of the step test was less than one-hird of standard ergospirometry (treadmill test: 654 +/- 151 s, step test: 180 s, p < 0.001). CONCLUSION: In large-scale epidemiological studies with limited time slots for exercise testing and significant proportions of subjects with low exercise capacity a modified version of the YMCA step test may be used to predict VO2peak.

Authors: F. Beutner, R. Ubrich, S. Zachariae, C. Engel, M. Sandri, A. Teren, S. Gielen

Date Published: 1st May 2014

Publication Type: Not specified

Validation of the Manchester scoring system for predicting BRCA1/2 mutations in 9,390 families suspected of having hereditary breast and ovarian cancer.
GC-HBOC - German Consortium for Hereditary Breast and Ovarian Cancer

Abstract (Expand)

The Manchester scoring system (MSS) allows the calculation of the probability for the presence of mutations in BRCA1 or BRCA2 genes in families suspected of having hereditary breast and ovarian cancer. … In 9,390 families, we determined the predictive performance of the MSS without (MSS-2004) and with (MSS-2009) consideration of pathology parameters. Moreover, we validated a recalibrated version of the MSS-2009 (MSS-recal). Families were included in the registry of the German Consortium for Hereditary Breast and Ovarian Cancer, using defined clinical criteria. Receiver operating characteristics (ROC) analysis was used to determine the predictive performance. The recalibrated model was developed using logistic regression analysis and tested using an independent random validation sample. The area under the ROC curves regarding a mutation in any of the two BRCA genes was 0.77 (95%CI 0.75-0.79) for MSS-2004, 0.80 (95%CI 0.78-0.82) for MSS-2009, and 0.82 (95%CI 0.80-0.83) for MSS-recal. Sensitivity at the 10% mutation probability cutoff was similar for all three models (MSS-2004 92.2%, MSS-2009 92.2%, and MSS-recal 90.3%), but specificity of MSS-recal (46.0%) was considerably higher than that of MSS-2004 (25.4%) and MSS-2009 (32.3%). In the MSS-recal model, almost all predictors of the original MSS were significantly predictive. However, the score values of some predictors, for example, high grade triple negative breast cancers, differed considerably from the originally proposed score values. The original MSS performed well in our sample of high risk families. The use of pathological parameters increased the predictive performance significantly. Recalibration improved the specificity considerably without losing much sensitivity.

Authors: K. Kast, R. K. Schmutzler, K. Rhiem, M. Kiechle, C. Fischer, D. Niederacher, N. Arnold, T. Grimm, D. Speiser, B. Schlegelberger, D. Varga, J. Horvath, M. Beer, S. Briest, A. Meindl, C. Engel

Date Published: 15th Nov 2014

Publication Type: Not specified

Human Diseases: breast cancer, ovarian cancer

Variability of structures in German intensive care units–a representative, nationwide analysis
SepNet - German Competence Network Sepsis

Abstract (Expand)

BACKGROUND Structures in intensive care medicine comprise human as well as material resources, organization, and management and may be related to processes thereby affecting patients’ outcomes. Utilizing …g a unique data base we evaluated structures of German intensive care units (ICUs). METHODS The study was carried out by the German Competence Network Sepsis (SepNet). Data were prospectively collected on a cross-sectional basis in a representative random sample of German hospitals utilizing a questionnaire. Structures were related to ICU outcome of patients with severe sepsis or septic shock. The sample was subdivided in 5 strata according to hospital size. RESULTS A total of 454 ICUs cared for 3877 patients including 415 patients (11%) with severe sepsis or septic shock. The mean number of beds per ICU was 10.4, the ratio of ICU to hospital beds 1:27, both with significant differences depending on hospital size. 81% of the ICUs provided around the clock physician presence (range: 66-98% across hospital strata, p \textless 0.001). Shift-wise, one nurse was responsible for a mean number of 2.7 patients (morning 1:2.3, afternoon 1:2.6, night 1:3.3 patients) with significant variation according to hospital size (smaller hospitals 1:2.9, university hospitals 1:2.1, p \textless 0.001). More than half of all German ICUs are lead by anesthesiologists. Neither physician nor nurse staffing was associated with mortality in the subset of patients with sepsis. CONCLUSIONS In a representative, nationwide sample of German ICUs key elements of structures varied considerably with respect to hospital size. This has to be considered when proposing standards, reimbursement strategies, or quality assessment.

Authors: Jürgen Graf, Andrea Reinhold, Frank M. Brunkhorst, Max Ragaller, Konrad Reinhart, Markus Loeffler, Christoph Engel

Date Published: 1st Oct 2010

Publication Type: Journal article

Human Diseases: disease by infectious agent

Ventilatory strategies in septic patients. Results from a nationwide observational trial
SepNet - German Competence Network Sepsis

Abstract (Expand)

BACKGROUND Mortality in intensive care unit (ICU) patients is affected by multiple variables. The possible impact of the mode of ventilation has not yet been clarified; therefore, a secondary analysis …s of the \textquotedblepidemiology of sepsis in Germany\textquotedbl study was performed. The aims were (1) to describe the ventilation strategies currently applied in clinical practice, (2) to analyze the association of the different modes of ventilation with mortality and (3) to investigate whether the ratio between arterial partial pressure of oxygen and inspired fraction of oxygen (PF ratio) and/or other respiratory variables are associated with mortality in septic patients needing ventilatory support. METHODS A total of 454 ICUs in 310 randomly selected hospitals participated in this national prospective observational 1-day point prevalence of sepsis study including 415 patients with severe sepsis or septic shock according to the American College of Chest Physicians/Society of Critical Care Medicine criteria. RESULTS Of the 415 patients, 331 required ventilatory support. Pressure controlled ventilation (PCV) was the most frequently used ventilatory mode (70.6 %) followed by assisted ventilation (AV 21.7 %) and volume controlled ventilation (VCV 7.7 %). Hospital mortality did not differ significantly among patients ventilated with PCV (57 %), VCV (71 %) or AV (51 %, p=0.23). A PF ratio equal or less than 300 mmHg was found in 83.2 % of invasively ventilated patients (n=316). In AV patients there was a clear trend to a higher PF ratio (204\pm70 mmHg) than in controlled ventilated patients (PCV 179\pm74 mmHg, VCV 175\pm75 mmHg, p=0.0551). Multiple regression analysis identified the tidal volume to pressure ratio (tidal volume divided by peak inspiratory airway pressure, odds ratio OR=0.94, 95 % confidence interval 95% CI=0.89-0.99), acute renal failure (OR=2.15, 95% CI=1.01-4.55) and acute physiology and chronic health evaluation (APACHE) II score (OR=1.09, 95% CI=1.03-1.15) but not the PF ratio (univariate analysis OR=0.998, 95 % CI=0.995-1.001) as independent risk factors for in-hospital mortality. CONCLUSIONS This representative survey revealed that severe sepsis or septic shock was frequently associated with acute lung injury. Different ventilatory modes did not affect mortality. The tidal volume to inspiratory pressure ratio but not the PF ratio was independently associated with mortality.

Authors: D. Schädler, G. Elke, C. Engel, H. Bogatsch, I. Frerichs, R. Kuhlen, R. Rossaint, M. Quintel, J. Scholz, F. M. Brunkhorst, M. Loeffler, K. Reinhart, N. Weiler

Date Published: 2013

Publication Type: Journal article

Human Diseases: disease by infectious agent

Viewing distance affects stereoscopic tilt created with spatial frequency disparity.
LIFE Adult

Abstract (Expand)

A controversy exists as to whether stereoscopic tilt created with interocular differences in spatial frequency is based on perception of spatial frequency disparity or positional disparity. To determine … which hypothesis is correct, we investigated the influence of viewing distance on perceived tilt. Tilt was induced by having observers view, at three viewing distances, dichoptic spatial frequency grating patterns differing in frequency by 25%. By appropriate physical scaling of the size of the patterns, their spatial frequency and angular width remained unchanged as distance varied. Under such conditions, the spatial frequency disparity hypothesis predicts no effect of distance, whereas the positional disparity hypothesis predicts a significant effect of distance (due to stereoscopic depth constancy) on the magnitude of tilt. The results showed that perceived tilt does covary with distance, a result consistent with only the positional disparity hypothesis.

Authors: R. Patterson, G. Burns, S. Mooney

Date Published: 1st Aug 1989

Publication Type: Not specified

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