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Comparing performance of modern genotype imputation methods in different ethnicities
Genetical Statistics and Systems Biology

Abstract (Expand)

A variety of modern software packages are available for genotype imputation relying on advanced concepts such as pre-phasing of the target dataset or utilization of admixed reference panels. In this … study, we performed a comprehensive evaluation of the accuracy of modern imputation methods on the basis of the publicly available POPRES samples. Good quality genotypes were masked and re-imputed by different imputation frameworks: namely MaCH, IMPUTE2, MaCH-Minimac, SHAPEIT-IMPUTE2 and MaCH-Admix. Results were compared to evaluate the relative merit of pre-phasing and the usage of admixed references. We showed that the pre-phasing framework SHAPEIT-IMPUTE2 can overestimate the certainty of genotype distributions resulting in the lowest percentage of correctly imputed genotypes in our case. MaCH-Minimac performed better than SHAPEIT-IMPUTE2. Pre-phasing always reduced imputation accuracy. IMPUTE2 and MaCH-Admix, both relying on admixed-reference panels, showed comparable results. MaCH showed superior results if well-matched references were available (Nei’s GST ≤ 0.010). For small to medium datasets, frameworks using genetically closest reference panel are recommended if the genetic distance between target and reference data set is small. Our results are valid for small to medium data sets. As shown on a larger data set of population based German samples, the disadvantage of pre-phasing decreases for larger sample sizes.

Authors: Nab Raj Roshyara, Katrin Horn, Holger Kirsten, Peter Ahnert, Markus Scholz

Date Published: 1st Dec 2016

Publication Type: Journal article

Sevoflurane and Isoflurane-Pharmacokinetics, Hemodynamic Stability, and Cardioprotective Effects During Cardiopulmonary Bypass
Genetical Statistics and Systems Biology

Abstract (Expand)

OBJECTIVES This study aimed to evaluate the pharmacokinetic profiles of sevoflurane and isoflurane during use of minimized extracorporeal circulation to perform coronary artery bypass graft surgery. …. Furthermore, cardiovascular stability during bypass and the postoperative release of troponins were evaluated. DESIGN Prospective, randomized study. SETTING University hospital. PARTICIPANTS The study comprised 31 adult patients undergoing coronary artery bypass grafting. INTERVENTIONS The pharmacokinetic measurements of the concentration of the volatile anesthetics in the arterial and venous blood, air inlet, air outlet, and gas exhaust of the extracorporeal circulation were recorded. Secondary end-points were cardiovascular stability during bypass, amount of postoperative release of troponin, time to extubation, time to discharge from the intensive care unit and the hospital, and 30-day mortality. MEASUREMENTS AND MAIN RESULTS Thirty patients completed the protocol. The pharmacokinetics of isoflurane and sevoflurane were almost identical, with a rapid wash-in (time to reach 50% of arterial steady state) concentration of 0.87\pm0.97 minutes and 1.14\pm0.35 minutes for isoflurane and sevoflurane, respectively, and a biphasic venous elimination with a terminal half-life of approximately 10 minutes for both compounds. There was a correlation between the gas inlet and the gas exhaust of the extracorporeal circulation. No difference in cardiovascular stability was found. High-sensitivity troponin concentrations on the first postoperative morning were 0.355\pm0.312 µg/mL and 0.225\pm0.111 µg/mL in the isoflurane and sevoflurane groups, respectively (p = 0.147). CONCLUSIONS The study found similar pharmacokinetics regarding wash-in and wash-out for sevoflurane and isoflurane. In addition, no difference in cardiovascular stability was found. The markers of cardiac damage were not different between the two anesthetics. Based on these data, sevoflurane and isoflurane might be used equivalently in patients undergoing coronary artery bypass graft surgery with extracorporeal circulation.

Authors: David Freiermuth, Berend Mets, Daniel Bolliger, Oliver Reuthebuch, Thomas Doebele, Markus Scholz, Michael Gregor, Matthias Haschke, Manfred Daniel Seeberger, Jens Fassl

Date Published: 1st Dec 2016

Publication Type: Journal article

Predicting early signs of dyslexia at a preliterate age by combining behavioral assessment with structural MRI
Genetical Statistics and Systems Biology

Abstract (Expand)

BACKGROUND Recent studies suggest that neurobiological anomalies are already detectable in pre-school children with a family history of developmental dyslexia (DD). However, there is a lack of longitudinal …l studies showing a direct link between those differences at a preliterate age and the subsequent literacy difficulties seen in school. It is also not clear whether the prediction of DD in pre-school children can be significantly improved when considering neurobiological predictors, compared to models based on behavioral literacy precursors only. METHODS We recruited 53 pre-reading children either with (N=25) or without a family risk of DD (N=28). Quantitative T1 MNI data and literacy precursor abilities were assessed at kindergarten age. A subsample of 35 children was tested for literacy skills either one or two years later, that is, either in first or second grade. RESULTS The group comparison of quantitative T1 measures revealed significantly higher T1 intensities in the left anterior arcuate fascicle (AF), suggesting reduced myelin concentration in preliterate children at risk of DD. A logistic regression showed that DD can be predicted significantly better (p=.024) when neuroanatomical differences between groups are used as predictors (80%) compared to a model based on behavioral predictors only (63%). The Wald statistic confirmed that the T1 intensity of the left AF is a statistically significant predictor of DD (p\textless.05). CONCLUSIONS Our longitudinal results provide evidence for the hypothesis that neuroanatomical anomalies in children with a family risk of DD are related to subsequent problems in acquiring literacy. Particularly, solid white matter organization in the left anterior arcuate fascicle seems to play a pivotal role.

Authors: Indra Kraft, Jan Schreiber, Riccardo Cafiero, Riccardo Metere, Gesa Schaadt, Jens Brauer, Nicole E. Neef, Bent Müller, Holger Kirsten, Arndt Wilcke, Johannes Boltze, Angela D. Friederici, Michael A. Skeide

Date Published: 1st Dec 2016

Publication Type: Journal article

Obesity is Associated with White Matter Changes and Cognitions among Healthy Elderly
LIFE - Leipzig Research Center for Civilization Diseases

Abstract (Expand)

Midlife obesity has often been associated with accelerated cognitive decline during aging. Obesity leads to changes in multiple physiological factors that could impact neuronal tissue. Numerous studies … have linked obesity and higher body mass index (BMI) with differences in cognitive functions and brain structure, including total brain volume, regional gray matter volume and white matter (WM) microstructure. However, regarding to WM, the available neuroimaging studies incorporated mainly small sample sizes that yielded less conclusive results. Thus, we investigated the association of obesity, measured using BMI and waist to hip ratio (WHR), with changes in WM microstructure, as well as variance in cognitive test scores in a large cohort of community-dwelling healthy individuals older than 60 years.

Authors: Rui Zhang, L. Lampe, Frauke Beyer, Sebastian Huhn, S. K. Masouleh, T. Luck, S. G. Riedel-Heller, Markus Löffler, M. L. Schroeter

Date Published: 28th Nov 2016

Publication Type: Not specified

Human Diseases: obesity

[Adverse drug reactions in elderly people : First data from the Leipzig Research Center for Civilization Diseases (LIFE)].
LIFE Adult

Abstract (Expand)

BACKGROUND: Few data exist on adverse drug reactions (ADR) in elderly people. In this group, pharmacotherapy represents a challenge with regard to comorbidities, drug interactions and compliance. … OBJECTIVE: The aim of this article is to highlight the characteristics of ADR in elderly patients. METHODS: In addition to a literature review we present the first data from the Leipzig Research Center for Civilization Diseases (LIFE). Between 2011 and 2015 a total of 9537 subjects aged 40-79 years were randomly included in this population-based, age and sex standardized investigation in the inhabitants of Leipzig, Germany and special emphasis was placed on allergies including questions with regard to ADR. RESULTS: Of the 9537 subjects, data on allergies were available from 8979 subjects. Female gender, comorbidities and the use of multiple drugs were significantly associated with an increased risk of ADR. Women also reported ADR significantly more frequently than men. Of the subjects 22% reported suffering from some form of ADR as a result of medications, while in 2.3% this reaction had occurred within the previous 12 months. Less than 15% of LIFE patients with ADR were in possession of a document giving details of the ADR. DISCUSSION: The occurrence of ADR significantly contributes to morbidity in elderly patients. For prevention of ADR knowledge of patient-related factors, underlying diseases, drug characteristics and drug interactions are necessary.

Authors: R. Treudler, F. Walther, P. Ahnert, J. C. Simon

Date Published: 23rd Nov 2016

Publication Type: Journal article

Outcomes of stable and unstable patterns of subjective cognitive decline - results from the Leipzig Longitudinal Study of the Aged (LEILA75+).
LIFE Adult

Abstract (Expand)

BACKGROUND: Subjective cognitive decline (SCD), i.e., the self-perceived feeling of worsening cognitive function, may be the first notable syndrome of preclinical Alzheimer's disease and other … dementias. However, not all individuals with SCD progress. Stability of SCD, i.e., repeated reports of SCD, could contribute to identify individuals at risk, as stable SCD may more likely reflect the continuous neurodegenerative process of Alzheimer's and other dementias. METHODS: Cox regression analyses were used to assess the association between stability of SCD and progression to MCI and dementia in data derived from the population-based Leipzig Longitudinal Study of the Aged (LEILA75+). RESULTS: Of 453 cognitively unimpaired individuals with a mean age of 80.5 years (SD = 4.2), 139 (30.7 %) reported SCD at baseline. Over the study period (M = 4.8 years, SD = 2.2), 84 (18.5 %) individuals had stable SCD, 195 (43.1 %) unstable SCD and 174 (38.4 %) never reported SCD. Stable SCD was associated with increased risk of progression to MCI and dementia (unadjusted HR = 1.8, 95 % CI = 1.2-2.6; p < .01), whereas unstable SCD yielded a decreased progression risk (unadjusted HR = 0.5, 95 % CI = 0.4-0.7; p < .001) compared to no SCD. When adjusted for baseline cognitive functioning, progression risk in individuals with stable SCD was significantly increased in comparison to individuals with unstable SCD, but not compared to individuals without SCD. CONCLUSIONS: Our results, though preliminary, suggest that stable SCD, i.e., repeated reports of SCD, may yield an increased risk of progression to MCI and dementia compared to unstable SCD. Baseline cognitive scores, though within a normal range, seem to be a driver of progression in stable SCD. Future research is warranted to investigate whether stability could hold as a SCD research feature.

Authors: S. Roehr, A. Villringer, M. C. Angermeyer, T. Luck, S. G. Riedel-Heller

Date Published: 4th Nov 2016

Publication Type: Journal article

Human Diseases: dementia, Alzheimer's disease

Effect of Hydrocortisone on Development of Shock Among Patients With Severe Sepsis: The HYPRESS Randomized Clinical Trial.
SepNet - German Competence Network Sepsis

Abstract (Expand)

Importance: Adjunctive hydrocortisone therapy is suggested by the Surviving Sepsis Campaign in refractory septic shock only. The efficacy of hydrocortisone in patients with severe sepsis without shock … remains controversial. Objective: To determine whether hydrocortisone therapy in patients with severe sepsis prevents the development of septic shock. Design, Setting, and Participants: Double-blind, randomized clinical trial conducted from January 13, 2009, to August 27, 2013, with a follow-up of 180 days until February 23, 2014. The trial was performed in 34 intermediate or intensive care units of university and community hospitals in Germany, and it included 380 adult patients with severe sepsis who were not in septic shock. Interventions: Patients were randomly allocated 1:1 either to receive a continuous infusion of 200 mg of hydrocortisone for 5 days followed by dose tapering until day 11 (n = 190) or to receive placebo (n = 190). Main Outcomes and Measures: The primary outcome was development of septic shock within 14 days. Secondary outcomes were time until septic shock, mortality in the intensive care unit or hospital, survival up to 180 days, and assessment of secondary infections, weaning failure, muscle weakness, and hyperglycemia (blood glucose level >150 mg/dL [to convert to millimoles per liter, multiply by 0.0555]). Results: The intention-to-treat population consisted of 353 patients (64.9% male; mean [SD] age, 65.0 [14.4] years). Septic shock occurred in 36 of 170 patients (21.2%) in the hydrocortisone group and 39 of 170 patients (22.9%) in the placebo group (difference, -1.8%; 95% CI, -10.7% to 7.2%; P = .70). No significant differences were observed between the hydrocortisone and placebo groups for time until septic shock; mortality in the intensive care unit or in the hospital; or mortality at 28 days (15 of 171 patients [8.8%] vs 14 of 170 patients [8.2%], respectively; difference, 0.5%; 95% CI, -5.6% to 6.7%; P = .86), 90 days (34 of 171 patients [19.9%] vs 28 of 168 patients [16.7%]; difference, 3.2%; 95% CI, -5.1% to 11.4%; P = .44), and 180 days (45 of 168 patients [26.8%] vs 37 of 167 patients [22.2%], respectively; difference, 4.6%; 95% CI, -4.6% to 13.7%; P = .32). In the hydrocortisone vs placebo groups, 21.5% vs 16.9% had secondary infections, 8.6% vs 8.5% had weaning failure, 30.7% vs 23.8% had muscle weakness, and 90.9% vs 81.5% had hyperglycemia. Conclusions and Relevance: Among adults with severe sepsis not in septic shock, use of hydrocortisone compared with placebo did not reduce the risk of septic shock within 14 days. These findings do not support the use of hydrocortisone in these patients. Trial Registration: clinicaltrials.gov Identifier: NCT00670254.

Authors: D. Keh, E. Trips, G. Marx, S. P. Wirtz, E. Abduljawwad, S. Bercker, H. Bogatsch, J. Briegel, C. Engel, H. Gerlach, A. Goldmann, S. O. Kuhn, L. Huter, A. Meier-Hellmann, A. Nierhaus, S. Kluge, J. Lehmke, M. Loeffler, M. Oppert, K. Resener, D. Schadler, T. Schuerholz, P. Simon, N. Weiler, A. Weyland, K. Reinhart, F. M. Brunkhorst

Date Published: 1st Nov 2016

Publication Type: Journal article

Human Diseases: disease by infectious agent

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