TY - GEN A1 - Winkelmann, Stefanie A1 - Schütte, Christof A1 - von Kleist, Max T1 - Markov Control Processes with Rare State Observation: Theory and Application to Treatment Scheduling in HIV-1 N2 - Markov Decision Processes (MDP) or Partially Observable MDPs (POMDP) are used for modelling situations in which the evolution of a process is partly random and partly controllable. These MDP theories allow for computing the optimal control policy for processes that can continuously or frequently be observed, even if only partially. However, they cannot be applied if state observation is very costly and therefore rare (in time). We present a novel MDP theory for rare, costly observations and derive the corresponding Bellman equation. In the new theory, state information can be derived for a particular cost after certain, rather long time intervals. The resulting information costs enter into the total cost and thus into the optimization criterion. This approach applies to many real world problems, particularly in the medical context, where the medical condition is examined rather rarely because examination costs are high. At the same time, the approach allows for efficient numerical realization. We demonstrate the usefulness of the novel theory by determining, from the national economic perspective, optimal therapeutic policies for the treatment of the human immunodefficiency virus (HIV) in resource-rich and resource-poor settings. Based on the developed theory and models, we discover that available drugs may not be utilized efficiently in resource-poor settings due to exorbitant diagnostic costs. T3 - ZIB-Report - 13-34 KW - information costs KW - hidden state KW - bellmann equation KW - optimal therapeutic policies KW - diagnostic frequency KW - resource-poor KW - resource-rich Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-41955 SN - 1438-0064 ER - TY - JOUR A1 - Rettig, Anika A1 - Haase, Tobias A1 - Pletnyov, Alexandr A1 - Kohl, Benjamin A1 - Ertel, Wolfgang A1 - von Kleist, Max A1 - Sunkara, Vikram T1 - SLCV – A Supervised Learning - Computer Vision combined strategy for automated muscle fibre detection in cross sectional images JF - PeerJ N2 - Muscle fibre cross sectional area (CSA) is an important biomedical measure used to determine the structural composition of skeletal muscle, and it is relevant for tackling research questions in many different fields of research. To date, time consuming and tedious manual delineation of muscle fibres is often used to determine the CSA. Few methods are able to automatically detect muscle fibres in muscle fibre cross sections to quantify CSA due to challenges posed by variation of bright- ness and noise in the staining images. In this paper, we introduce SLCV, a robust semi-automatic pipeline for muscle fibre detection, which combines supervised learning (SL) with computer vision (CV). SLCV is adaptable to different staining methods and is quickly and intuitively tunable by the user. We are the first to perform an error analysis with respect to cell count and area, based on which we compare SLCV to the best purely CV-based pipeline in order to identify the contribution of SL and CV steps to muscle fibre detection. Our results obtained on 27 fluorescence-stained cross sectional images of varying staining quality suggest that combining SL and CV performs signifi- cantly better than both SL based and CV based methods with regards to both the cell separation- and the area reconstruction error. Furthermore, applying SLCV to our test set images yielded fibre detection results of very high quality, with average sensitivity values of 0.93 or higher on different cluster sizes and an average Dice Similarity Coefficient (DSC) of 0.9778. T3 - ZIB-Report - 19-10 Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-72639 PB - PeerJ CY - PeerJ ER - TY - JOUR A1 - Ozel, Mehmet Neset A1 - Kulkarni, Abhishek A1 - Hasan, Amr A1 - Brummer, Josephine A1 - Moldenhauer, Marian A1 - Daumann, Ilsa-Maria A1 - Wolfenberg, Heike A1 - Dercksen, Vincent J. A1 - Kiral, Ferdi Ridvan A1 - Weiser, Martin A1 - Prohaska, Steffen A1 - von Kleist, Max A1 - Hiesinger, Peter Robin T1 - Serial synapse formation through filopodial competition for synaptic seeding factors JF - Developmental Cell N2 - Following axon pathfinding, growth cones transition from stochastic filopodial exploration to the formation of a limited number of synapses. How the interplay of filopodia and synapse assembly ensures robust connectivity in the brain has remained a challenging problem. Here, we developed a new 4D analysis method for filopodial dynamics and a data-driven computational model of synapse formation for R7 photoreceptor axons in developing Drosophila brains. Our live data support a 'serial synapse formation' model, where at any time point only a single 'synaptogenic' filopodium suppresses the synaptic competence of other filopodia through competition for synaptic seeding factors. Loss of the synaptic seeding factors Syd-1 and Liprin-α leads to a loss of this suppression, filopodial destabilization and reduced synapse formation, which is sufficient to cause the destabilization of entire axon terminals. Our model provides a filopodial 'winner-takes-all' mechanism that ensures the formation of an appropriate number of synapses. Y1 - 2019 U6 - https://doi.org/10.1016/j.devcel.2019.06.014 VL - 50 IS - 4 SP - 447 EP - 461 ER - TY - JOUR A1 - Gupta, Pooja A1 - Peter, Sarah A1 - Jung, Markus A1 - Lewin, Astrid A1 - Hemmrich-Stanisak, Georg A1 - Franke, Andre A1 - von Kleist, Max A1 - Schütte, Christof A1 - Einspanier, Ralf A1 - Sharbati, Soroush A1 - zur Bruegge, Jennifer T1 - Analysis of long non-coding RNA and mRNA expression in bovine macrophages brings up novel 2 aspects of Mycobacterium avium subspecies paratuberculosis infections JF - Scientific Reports in Nature N2 - Paratuberculosis is a major disease in cattle that severely affects animal welfare and causes huge economic losses worldwide. Development of alternative diagnostic methods is of urgent need to control the disease. Recent studies suggest that long non-coding RNAs (lncRNAs) play a crucial role in regulating immune function and may confer valuable information about the disease. However, their role has not yet been investigated in cattle with respect to infection towards Paratuberculosis. Therefore, we investigated the alteration in genomic expression profiles of mRNA and lncRNA in bovine macrophages in response to Paratuberculosis infection using RNA-Seq. We identified 397 potentially novel lncRNA candidates in macrophages of which 38 were differentially regulated by the infection. A total of 820 coding genes were also significantly altered by the infection. Co-expression analysis of lncRNAs and their neighbouring coding genes suggest regulatory functions of lncRNAs in pathways related to immune response. For example, this included protein coding genes such as TNIP3, TNFAIP3 and NF-κB2 that play a role in NF-κB2 signalling, a pathway associated with immune response. This study advances our understanding of lncRNA roles during Paratuberculosis infection. Y1 - 2019 U6 - https://doi.org/10.1038/s41598-018-38141-x VL - 9 ER - TY - JOUR A1 - Duwal, Sulav A1 - Winkelmann, Stefanie A1 - Schütte, Christof A1 - von Kleist, Max T1 - Optimal Treatment Strategies in the Context of 'Treatment for Prevention' against HIV/1 in Resource-Poor Settings JF - PloS Computational Biology N2 - An estimated 2.7 million new HIV-1 infections occurred in 2010. `Treatment-for-prevention’ may strongly prevent HIV-1 transmission. The basic idea is that immediate treatment initiation rapidly decreases virus burden, which reduces the number of transmittable viruses and thereby the probability of infection. However, HIV inevitably develops drug resistance, which leads to virus rebound and nullifies the effect of `treatment-for-prevention’ for the time it remains unrecognized. While timely conducted treatment changes may avert periods of viral rebound, necessary treatment options and diagnostics may be lacking in resource-constrained settings. Within this work, we provide a mathematical platform for comparing different treatment paradigms that can be applied to many medical phenomena. We use this platform to optimize two distinct approaches for the treatment of HIV-1: (i) a diagnostic-guided treatment strategy, based on infrequent and patient-specific diagnostic schedules and (ii) a pro-active strategy that allows treatment adaptation prior to diagnostic ascertainment. Both strategies are compared to current clinical protocols (standard of care and the HPTN052 protocol) in terms of patient health, economic means and reduction in HIV-1 onward transmission exemplarily for South Africa. All therapeutic strategies are assessed using a coarse-grained stochastic model of within-host HIV dynamics and pseudo-codes for solving the respective optimal control problems are provided. Our mathematical model suggests that both optimal strategies (i)-(ii) perform better than the current clinical protocols and no treatment in terms of economic means, life prolongation and reduction of HIV-transmission. The optimal diagnostic-guided strategy suggests rare diagnostics and performs similar to the optimal pro-active strategy. Our results suggest that ‘treatment-for-prevention’ may be further improved using either of the two analyzed treatment paradigms. Y1 - 2015 U6 - https://doi.org/10.1371/journal.pcbi.1004200 VL - 11 IS - 4 ER - TY - JOUR A1 - Duwal, Sulav A1 - Schütte, Christof A1 - von Kleist, Max T1 - Pharmacokinetics and Pharmacodynamics of the Reverse Transcriptase Inhibitor Tenofovir & Prophylactic Efficacy against HIV-1 Infection. JF - PLoS One Y1 - 2012 UR - http://publications.imp.fu-berlin.de/1130/ U6 - https://doi.org/10.1371/journal.pone.0040382 VL - 7 IS - 7 SP - e40382 ER - TY - JOUR A1 - von Kleist, Max A1 - Metzner, Ph. A1 - Marquet, R. A1 - Schütte, Christof T1 - Polymerase Inhibition by Nucleoside Analogs JF - Plos Computational Biology Y1 - 2012 UR - http://publications.imp.fu-berlin.de/1087/ U6 - https://doi.org/10.1371/journal.pcbi.1002359 VL - 8 IS - 1 SP - e1002359 ER - TY - JOUR A1 - von Kleist, Max A1 - Menz, Stephan A1 - Stocker, Hartmut A1 - Arasteh, Keikawus A1 - Huisinga, Wilhelm A1 - Schütte, Christof T1 - HIV Quasispecies Dynamics during Pro-active Treatment Switching JF - Plos One Y1 - 2011 UR - http://publications.imp.fu-berlin.de/1051/ U6 - https://doi.org/10.1371/journal.pone.0018204 VL - 6 IS - 3 SP - e18204 PB - Public Library of Science ER - TY - JOUR A1 - Frank, M. A1 - von Kleist, Max A1 - Kunz, A. A1 - Harms, G. A1 - Schütte, Christof A1 - Kloft, Ch. T1 - Quantifying the impact of nevirapine-based prophylaxis strategies to prevent mother-to-child transmission of HIV-1 JF - Antimicrob. Agents Chemother. Y1 - 2011 UR - http://publications.imp.fu-berlin.de/1093/ VL - 55 IS - 12 SP - 5529 EP - 5540 ER - TY - JOUR A1 - Rath, Barbara A1 - Yousef, Kaveh A1 - Katzenstein, D. A1 - Shafer, R. A1 - Schütte, Christof A1 - von Kleist, Max A1 - Merigan, T. T1 - HIV-1 Evolution in Response to Triple Reverse Transcriptase Inhibitor Induced Selective Pressure in vitro JF - PLoS ONE Y1 - 2013 UR - http://publications.imp.fu-berlin.de/1178/ U6 - https://doi.org/10.1371/journal.pone.0061102 VL - 8 IS - 4 PB - Public Library of Science ER -