192 research outputs found

    Unifying Parsimonious Tree Reconciliation

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    Evolution is a process that is influenced by various environmental factors, e.g. the interactions between different species, genes, and biogeographical properties. Hence, it is interesting to study the combined evolutionary history of multiple species, their genes, and the environment they live in. A common approach to address this research problem is to describe each individual evolution as a phylogenetic tree and construct a tree reconciliation which is parsimonious with respect to a given event model. Unfortunately, most of the previous approaches are designed only either for host-parasite systems, for gene tree/species tree reconciliation, or biogeography. Hence, a method is desirable, which addresses the general problem of mapping phylogenetic trees and covering all varieties of coevolving systems, including e.g., predator-prey and symbiotic relationships. To overcome this gap, we introduce a generalized cophylogenetic event model considering the combinatorial complete set of local coevolutionary events. We give a dynamic programming based heuristic for solving the maximum parsimony reconciliation problem in time O(n^2), for two phylogenies each with at most n leaves. Furthermore, we present an exact branch-and-bound algorithm which uses the results from the dynamic programming heuristic for discarding partial reconciliations. The approach has been implemented as a Java application which is freely available from http://pacosy.informatik.uni-leipzig.de/coresym.Comment: Peer-reviewed and presented as part of the 13th Workshop on Algorithms in Bioinformatics (WABI2013

    A retrospective analysis of the diagnostic performance of 11C-choline PET/CT for detection of hyperfunctioning parathyroid glands after prior negative or discordant imaging in primary hyperparathyroidism

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    BACKGROUND: Identifying the correct location of a parathyroid adenoma in patients with primary hyperparathyroidism (pHPT) is crucial as it can guide surgical treatment. This study aimed to determine the diagnostic performance of 11C-choline PET/CT in patients with pHPT as a next in-line scan after primary negative or discordant first-line imaging. METHODS: This was a retrospective single-center cohort study. All patients with pHPT that were scanned utilizing 11C-choline PET/CT, after prior negative or discordant imaging, between 2015 and 2019 and who subsequently underwent parathyroid surgery were included. The results of the 11C-choline PET/CT were evaluated lesion-based, with surgical exploration and histopathological examination as the gold standard. RESULTS: In total, 36 patients were included of which three patients were known to have Multiple Endocrine Neoplasia (MEN) syndrome. In these 36 patients, 40 lesions were identified on 11C-choline PET/CT and 37 parathyroid lesions were surgically removed. In 34/36 (94%) patients a focused parathyroidectomy was performed, in one patient a cervical exploration due to an ectopically identified adenoma, and in one patient a bilateral exploration was performed because of a double adenoma. Overall, per-lesion sensitivity of 11C-choline PET/CT was 97%, the positive predictive value was 95% and the accuracy was 94% for all parathyroid lesions. CONCLUSIONS: In patients with pHPT and prior negative or discordant first-line imaging results, pathological parathyroid glands can be localized by 11C-choline PET/CT with high sensitivity and accuracy

    Comparison of [18F]DOPA and [68Ga]DOTA-TOC as a PET imaging tracer before peptide receptor radionuclide therapy

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    BACKGROUND: In treatment of neuroendocrine neoplasms (NENs), confirmation of somatostatin receptor expression with 68Ga-DOTA somatostatin analogues is mandatory to determine eligibility for peptide receptor radionuclide therapy (PRRT). [18F]DOPA can detect additional lesions compared to [68Ga]DOTA-TOC. The aim of this study was to explore differences in tumour detection of both tracers and their relevance for selecting patients for PRRT. We retrospectively studied eight patients with NENs who underwent both [68Ga]DOTA-TOC and carbidopa-enhanced [18F]DOPA PET/CT, before first-time PRRT with [177Lu]DOTA-TATE. Tracer order was influenced due to stock availability or to detect suspected metastases with a second tracer. On CT, disease control was defined as a lesion showing complete response, partial response, or stable disease, according to RECIST 1.1. CRITERIA: RESULTS: Seven patients with in total 89 lesions completed four infusions of 7.4 GBq [177Lu]DOTA-TATE, one patient received only two cycles. Before treatment, [18F]DOPA PET/CT detected significantly more lesions than [68Ga]DOTA-TOC PET/CT (79 vs. 62, p < .001). After treatment, no difference in number of lesions with disease control was found for [18F]DOPA-only (5/27) and [68Ga]DOTA-TOC-only lesions (4/10, p = .25). [18F]DOPA detected more liver metastases (24/27) compared to [68Ga]DOTA-TOC (7/10, p = .006). Six patients showed inpatient heterogeneity in treatment response between [18F]DOPA-only and [68Ga]DOTA-TOC-only lesions. CONCLUSIONS: Response to PRRT with [177Lu]DOTA-TATE was comparable for both [68Ga]DOTA-TOC- and [18F]DOPA-only NEN lesions. [18F]DOPA may be capable of predicting response to PRRT while finding more lesions compared to [68Ga]DOTA-TOC, although these additional lesions are often small of size and undetected by diagnostic CT

    Dynamic Interactive Social Cognition Training in Virtual Reality (DiSCoVR) for social cognition and social functioning in people with a psychotic disorder:study protocol for a multicenter randomized controlled trial

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    Problems in social functioning (e.g., unemployment, social isolation), are common in people with a psychotic disorder. Social cognition is a treatment target to improve social functioning, as it is a proximal predictor of social functioning. Social Cognition Training (SCT) improves social cognition, but may not generalize (enduringly) to social functioning, perhaps due to insufficient opportunity to practice in daily-life social situations. Using virtual reality (VR) for SCT could address this problem, as VR is customizable, accessible, and interactive. We will test the effect of a VR SCT, 'DiSCoVR', on social cognition and social functioning in a randomized controlled trial (RCT).  In total 100 people with a psychotic disorder and deficits in social cognition will be recruited for this multicenter randomized controlled trial (RCT). Participants will be randomized to VR SCT (DiSCoVR) or VR relaxation training (VRelax; active control). DiSCoVR is a 16-session individual SCT, consisting of three modules: 1) emotion perception (recognizing facial emotions in a virtual shopping street); 2) social perception and theory of mind (observing social interactions between virtual characters and assessing their behavior, emotions and thoughts); and 3) application of higher-order social cognition in social interaction (role-playing personalized situations in VR). People receiving VRelax complete sixteen individual sessions, in which they receive psycho-education about stress, identify personal stressors, learn relaxation techniques, and explore relaxing immersive virtual environments. Assessments will be performed at baseline, post-treatment, and 3-month follow-up. Primary outcomes are emotion perception (Ekman 60 Faces), social perception and theory of mind (The Awareness of Social Inference Test). Secondary outcomes include social functioning (Personal and Social Performance Scale), experiences and social interactions in daily life (experience sampling of emotions, social participation and subjective experience of social situations), psychiatric symptoms (e.g., depression, perceived stress, anxiety, positive and negative symptoms) and self-esteem.  To our knowledge, this will be the first RCT testing the efficacy of VR SCT. It will also investigate generalization to daily life social situations, the durability of treatment effects, and moderators and mediators of treatment success

    Virtual reality cognitive-behavioural therapy versus cognitive-behavioural therapy for paranoid delusions:a study protocol for a single-blind multi-Centre randomised controlled superiority trial

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    Abstract Background Seventy per cent of patients with psychotic disorders has paranoid delusions. Paranoid delusions are associated with significant distress, hospital admission and social isolation. Cognitive-behavioural therapy for psychosis (CBTp) is the primary psychological treatment, but the median effect size is only small to medium. Virtual reality (VR) has a great potential to improve the effectiveness of CBTp. In a previous study, we found that VR based CBT (VRcbt) for paranoid delusions is superior to waiting list. As a next step, a direct comparison with CBTp is needed. The present study aims to investigate whether VRcbt is more effective and cost-effective than regular CBTp in treating paranoid delusions and improving daily life social functioning of patients with psychotic disorders. Methods A total of 106 patients with DSM-5 diagnosis of psychotic disorder and at least moderate level of paranoid ideations will be recruited for this multicentre randomized controlled trial (RCT). Patients will be randomized to either VRcbt or standard CBTp for paranoid delusions. VRcbt consists of maximum 16 sessions in virtual social situations that trigger paranoid ideations and distress, delivered in an 8–12 week time frame. Standard CBTp also consists of maximum 16 sessions including exposure and behavioural experiments, delivered in an 8–12 week time frame. The two groups will be compared at baseline, post-treatment and six months follow-up. Primary outcome is the level of paranoid ideations in daily life social situations, measured with ecological momentary assessments (EMA) at semi-random moments ten times a day during seven days, before and after treatment. Every session, participants and therapists will rate the level of paranoid ideation and global clinical impression. Discussion Comparison of VRcbt and CBTp will provide information about the relative (cost-) effectiveness of VRcbt for this population. VRcbt may become a preferred psychological treatment for paranoid delusions and social anxiety in patients with psychotic disorder. Trial registration Netherlands Trial Register, NL7758. Registered on 23 May 2019

    Diagnosing pancreatic neuroendocrine tumors in patients with multiple endocrine neoplasia type 1 in daily practice

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    Background: In multiple endocrine neoplasia type 1 (MEN1), pancreatic neuroendocrine tumors (PanNETs) have a high prevalence and represent the main cause of death. This study aimed to assess the diagnostic accuracy of the currently used conventional pancreatic imaging techniques and the added value of fine needle aspirations (FNAs). Methods: Patients who had at least one imaging study were included from the population-based MEN1 database of the DutchMEN Study Group from 1990 to 2017. Magnetic resonance imaging (MRI), computed tomography (CT), endoscopic ultrasonography (EUS), FNA, and surgical resection specimens were obtained. The first MRI, CT, or EUS was considered as the index test. For a comparison of the diagnostic accuracy of MRI versus CT, patients with their index test taken between 2010 and 2017 were included. The reference standard consisted of surgical histopathology or radiological follow-up. ResultsA total of 413 patients (92.8% of the database) underwent 3,477 imaging studies. The number of imaging studies per patient increased, and a preference for MRI was observed in the last decade. Overall diagnostic accuracy was good with a positive (PPV) and negative predictive value (NPV) of 88.9% (95% confidence interval, 76.0-95.6) and 92.8% (89.4-95.1), respectively, for PanNET in the pancreatic head and 92.0% (85.3-96.0) and 85.3% (80.5-89.1), respectively, in the body/tail. For MRI, PPV and NPV for pancreatic head tumors were 100% (76.1-100) and 87.1% (76.3-93.6) and for CT, 60.0% (22.9-88.4) and 70.4% (51.3-84.3), respectively. For body/tail tumors, PPV and NPV were 91.3% (72.0-98.8) and 87.0% (75.3-93.9), respectively, for MRI and 100% (74.9-100) and 77.8% (54.3-91.5), respectively, for CT. Pathology confirmed a PanNET in 106 out of 110 (96.4%) resection specimens. FNA was performed on 34 lesions in 33 patients and was considered PanNET in 24 [all confirmed PanNET by histology (10) or follow-up (14)], normal/cyst/unrepresentative in 6 (all confirmed PanNET by follow-up), and adenocarcinoma in 4 (2 confirmed and 2 PanNET). Three patients, all older than 60 years, had a final diagnosis of pancreatic adenocarcinoma. Conclusion: As the accuracy for diagnosing MEN1-related PanNET of MRI was higher than that of CT, MRI should be the preferred (non-invasive) imaging modality for PanNET screening/surveillance. The high diagnostic accuracy of pancreatic imaging and the sporadic occurrence of pancreatic adenocarcinoma question the need for routine (EUS-guided) FNA

    Dynamic Interactive Social Cognition Training in Virtual Reality (DiSCoVR) for People With a Psychotic Disorder: Single-Group Feasibility and Acceptability Study

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    Background: People with a psychotic disorder commonly experience problems in social cognition and functioning. Social cognition training (SCT) improves social cognition, but may inadequately simulate real-life social interactions. Virtual reality (VR) provides a realistic, interactive, customizable, and controllable training environment, which could facilitate the application of skills in daily life. Objective: We developed a 16-session immersive VR SCT (Dynamic Interactive Social Cognition Training in Virtual Reality [DiSCoVR]) and conducted a single-group feasibility pilot study. Methods: A total of 22 people with a psychotic disorder and reported problems in social cognition participated. Feasibility and acceptability were assessed using a survey for participants and therapists, and by examining relevant parameters (eg, dropouts). We analyzed preliminary treatment effects on social cognition, neurocognition, and psychiatric symptoms. Results: A total of 17 participants completed the study. Participants enjoyed DiSCoVR (mean 7.25, SD 2.05; range 3-10), thought it was useful for daily social activities (mean 7.00, SD 2.05; range 3-10), and enjoyed the combination of VR and a therapist (mean 7.85, SD 2.11; range 3-10). The most frequently mentioned strength of DiSCoVR was the opportunity to practice with personalized social situations (14/20, 70%). A significant improvement of emotion perception was observed (Ekman 60 Faces; t16=–4.79, P<.001, d=–0.67), but no significant change was found in other measures of social cognition, neurocognition, psychiatric symptoms, or self-esteem. Conclusions: DiSCoVR was feasible and acceptable to participants and therapists, and may improve emotion perception

    Initiating pancreatic neuroendocrine tumour (pNET) screening in young MEN1 patients:results from the DutchMEN Study Group

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    Context: Nonfunctioning pancreatic neuroendocrine tumors (NF-pNETs) are highly prevalent and constitute an important cause of mortality in patients with multiple endocrine neoplasia type 1 (MEN1). Still, the optimal age to initiate screening for pNETs is under debate. Objective: The aim of this work is to assess the age of occurrence of clinically relevant NF-pNETs in young MEN1 patients. Methods: Pancreatic imaging data of MEN1 patients were retrieved from the DutchMEN Study Group database. Interval-censored survival methods were used to describe age-related penetrance, compare survival curves, and develop a parametric model for estimating the risk of having clinically relevant NF-pNET at various ages. The primary objective was to assess age at occurrence of clinically relevant NF-pNET (size ≥†20 mm or rapid growth); secondary objectives were the age at occurrence of NF-pNET of any size and pNET-associated metastasized disease. Results: Five of 350 patients developed clinically relevant NF-pNETs before age 18 years, 2 of whom subsequently developed lymph node metastases. No differences in clinically relevant NF-pNET-free survival were found for sex, time frame, and type of MEN1 diagnosis or genotype. The estimated ages (median, 95% CI) at a 1%, 2.5%, and 5% risk of having developed a clinically relevant tumor are 9.5 (6.5-12.7), 13.5 (10.2-16.9), and 17.8 years (14.3-21.4), respectively. Conclusion: Analyses from this population-based cohort indicate that start of surveillance for NF-pNETs with pancreatic imaging at age 13 to 14 years is justified. The psychological and medical burden of screening at a young age should be considered

    Enhanced axonal response of mitochondria to demyelination offers neuroprotection:implications for multiple sclerosis

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    Axonal loss is the key pathological substrate of neurological disability in demyelinating disorders, including multiple sclerosis (MS). However, the consequences of demyelination on neuronal and axonal biology are poorly understood. The abundance of mitochondria in demyelinated axons in MS raises the possibility that increased mitochondrial content serves as a compensatory response to demyelination. Here, we show that upon demyelination mitochondria move from the neuronal cell body to the demyelinated axon, increasing axonal mitochondrial content, which we term the axonal response of mitochondria to demyelination (ARMD). However, following demyelination axons degenerate before the homeostatic ARMD reaches its peak. Enhancement of ARMD, by targeting mitochondrial biogenesis and mitochondrial transport from the cell body to axon, protects acutely demyelinated axons from degeneration. To determine the relevance of ARMD to disease state, we examined MS autopsy tissue and found a positive correlation between mitochondrial content in demyelinated dorsal column axons and cytochromecoxidase (complex IV) deficiency in dorsal root ganglia (DRG) neuronal cell bodies. We experimentally demyelinated DRG neuron-specific complex IV deficient mice, as established disease models do not recapitulate complex IV deficiency in neurons,and found that these mice are able to demonstrate ARMD, despite the mitochondrial perturbation.Enhancement of mitochondrial dynamics in complex IV deficient neurons protects the axon upon demyelination. Consequently, increased mobilisation of mitochondria from the neuronal cell body to the axon is a novel neuroprotective strategy for the vulnerable, acutely demyelinated axon. We propose that promoting ARMD is likely to be a crucial preceding step for implementing potential regenerative strategies for demyelinating disorders.</p
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