373 research outputs found
Growth performance, carcass traits, and blood biochemistry of broiler chicks fed with low-fibre sunflower meal and phytase
This study was designed to evaluate the impact of graded replacements of soybean meal (SBM) with low-fibre sunflower meal (LF-SFM), with and without phytase supplementation, on growth performance, carcass traits, and plasma profile of broilers. A total of 800 mixed sex one-day-old broiler chicks (Cobb 500) were randomly assigned to eight dietary treatment groups (five replicates each) in a 4 × 2 factorial arrangement, including four levels of LF-SFM (0%, 25%, 50%, and 75% to replace SBM) and two levels of microbial phytase (0 or 0.2 g/kg diet). Feed conversion ratio (FCR), and bodyweight gain (BWG) were decreased significantly if LF-SFM replaced more than 25% SBM. There was no significant effect between the interaction of the main factors (LF-SFM × phytase) on growth performance during the starter, grower, finisher and the overall period. The addition of phytase had no beneficial effects on performance traits. Carcass traits were not influenced by feeding LF-SFM or enzyme addition. However, increasing the level of LF-SFM (50% and 75%, respectively) in diets reduced the abdominal fat, whereas the weight of the small intestine was increased. Plasma metabolic profile was not affected by LF-SFM levels in broiler diets, except for high-density lipoproteins cholesterol (HDL-C) and total cholesterol (T-Cho), which were not affected by the dietary enzyme. It is concluded that the diets with LF-SFM levels up to 25% generated growth performance and carcass traits comparable with the diet that contained SBM.Keywords: Cobb 500, digestive organs, enzyme, growth traits, low-fibre sunflower meal, plasma profil
Personalized treatment of brain metastases: Evolving survival prediction models may benefit from evaluation of serum tumor markers (narrative review)
Treatment of a limited number of brain metastases (oligometastases) might include complex and sometimes invasive approaches, e.g. neurosurgical resection followed by post-operative stereotactic radiotherapy, and thus, correct identification of patients who are appropriate candidates is crucial. Both, staging procedures that visualize the true number of metastastic lesions and prognostic assessments that identify patients with limited survival, who should be managed with less complex, palliative approaches, are necessary before proceeding with local treatment that aims at eradication of all oligometastases. Some of the prognostic models, e.g. the LabBM score (laboratory parameters in patients with brain metastases), include blood biomarkers believed to represent surrogate markers of disease extent. In a recent study, patients with oligometastases and a LabBM score of 0 (no abnormal biomarkers) had an actuarial 5-year survival rate of 27% after neurosurgical resection and 39% after stereotactic radiotherapy. Other studies have tied serum tumor markers such as carcinoembryonic antigen (CEA) to survival outcomes. Even if head-to-head comparisons and large-scale definitive analyses are lacking, the available data suggest that attempts to integrate tumor marker levels in blood biomarker-based survival prediction models are warranted
Personalized radiotherapy of brain metastases: survival prediction by means of dichotomized or differentiated blood test results?
Background and objectives: The validated LabBM score (laboratory parameters in patients with brain metastases) represents a widely applicable survival prediction model, which incorporates 5 blood test results (serum lactate dehydrogenase (LDH), C-reactive protein (CRP), albumin, platelets and hemoglobin). All tests are classified as normal or abnormal, without accounting for the wide range of abnormality observed in practice. We tested the hypothesis that improved stratification might be possible, if more granular test results are employed.
Methods: Retrospective analysis of 198 patients managed with primary whole-brain radiotherapy in one of the institutions who validated the original LabBM score.
Results: For two blood tests (albumin, CRP), discrimination was best for the original dichotomized version (normal/abnormal). For two others (LDH, hemoglobin), a three-tiered classification was best. The number of patients with low platelet count was not large enough for detailed analyses. A modified LabBM score was developed, which separates the intermediate of originally 3 prognostic groups into 2 statistically significantly different strata, resulting in a 4-tiered score.
Conclusion: This initial proof-of-principle study suggests that granular blood test results might contribute to further improvement of the score, or alternatively development of a nomogram, if additional large-scale studies confirm the encouraging results of the present analysis
Personalized treatment of brain metastases: Evolving survival prediction models may benefit from evaluation of serum tumor markers (narrative review)
Treatment of a limited number of brain metastases (oligometastases) might include complex and sometimes invasive approaches, e.g. neurosurgical resection followed by post-operative stereotactic radiotherapy, and thus, correct identification of patients who are appropriate candidates is crucial. Both, staging procedures that visualize the true number of metastastic lesions and prognostic assessments that identify patients with limited survival, who should be managed with less complex, palliative approaches, are necessary before proceeding with local treatment that aims at eradication of all oligometastases. Some of the prognostic models, e.g. the LabBM score (laboratory parameters in patients with brain metastases), include blood biomarkers believed to represent surrogate markers of disease extent. In a recent study, patients with oligometastases and a LabBM score of 0 (no abnormal biomarkers) had an actuarial 5-year survival rate of 27% after neurosurgical resection and 39% after stereotactic radiotherapy. Other studies have tied serum tumor markers such as carcinoembryonic antigen (CEA) to survival outcomes. Even if head-to-head comparisons and large-scale definitive analyses are lacking, the available data suggest that attempts to integrate tumor marker levels in blood biomarker-based survival prediction models are warranted.
Keywords: biomarkers; brain metastases; prognostic model; score; tumor marker
How we treat octogenarians with brain metastases
Biologically younger, fully independent octogenarians are able to tolerate most oncological treatments. Increasing frailty results in decreasing eligibility for certain treatments, e.g., chemotherapy and surgery. Most brain metastases are not an isolated problem, but part of widespread cancer dissemination, often in combination with compromised performance status. Multidisciplinary assessment is key in this vulnerable patient population where age, frailty, comorbidity and even moderate additional deficits from brain metastases or their treatment may result in immobilization, hospitalization, need for nursing home care, termination of systemic anticancer treatment etc. Here, we provide examples of successful treatment (surgery, radiosurgery, systemic therapy) and best supportive care, and comment on the limitations of prognostic scores, which often were developed in all-comers rather than octogenarians. Despite selection bias in retrospective studies, survival after radiosurgery was more encouraging than after whole-brain radiotherapy. Prospective research with focus on octogenarians is warranted to optimize outcomes
Attacking the V:On the resiliency of adaptive-horizon MPC
Inspired by the emerging problem of CPS security, we introduce the concept of controller-attacker games. A controller-attacker game is a two-player stochastic game, where the two players, a controller and an attacker, have antagonistic objectives. A controller-attacker game is formulated in terms of a Markov Decision Process (MDP), with the controller and the attacker jointly determining the MDP’s transition probabilities. We also introduce the class of controller-attacker games we call V-formation games, where the goal of the controller is to maneuver the plant (a simple model of flocking dynamics) into a V-formation, and the goal of the attacker is to prevent the controller from doing so. Controllers in V-formation games utilize a new formulation of model-predictive control we have developed called Adaptive-Horizon MPC (AMPC), giving them extraordinary power: we prove that under certain controllability conditions, an AMPC controller can attain V-formation with probability 1. We evaluate AMPC’s performance on V-formation games using statistical model checking. Our experiments demonstrate that (a) as we increase the power of the attacker, the AMPC controller adapts by suitably increasing its horizon, and thus demonstrates resiliency to a variety of attacks; and (b) an intelligent attacker can significantly outperform its naive counterpart
Analysis of parametric biological models with non-linear dynamics
In this paper we present recent results on parametric analysis of biological
models. The underlying method is based on the algorithms for computing
trajectory sets of hybrid systems with polynomial dynamics. The method is then
applied to two case studies of biological systems: one is a cardiac cell model
for studying the conditions for cardiac abnormalities, and the second is a
model of insect nest-site choice.Comment: In Proceedings HSB 2012, arXiv:1208.315
Amino-acid PET versus MRI guided re-irradiation in patients with recurrent glioblastoma multiforme (GLIAA) – protocol of a randomized phase II trial (NOA 10/ARO 2013-1)
Background: The higher specificity of amino-acid positron emission tomography (AA-PET) in the diagnosis of gliomas, as well as in the differentiation between recurrence and treatment-related alterations, in comparison to contrast enhancement in T1-weighted MRI was demonstrated in many studies and is the rationale for their implementation into radiation oncology treatment planning. Several clinical trials have demonstrated the significant differences between AA-PET and standard MRI concerning the definition of the gross tumor volume (GTV). A small single-center non-randomized prospective study in patients with recurrent high grade gliomas treated with stereotactic fractionated radiotherapy (SFRT) showed a significant improvement in survival when AA-PET was integrated in target volume delineation, in comparison to patients treated based on CT/MRI alone. Methods: This protocol describes a prospective, open label, randomized, multi-center phase II trial designed to test if radiotherapy target volume delineation based on FET-PET leads to improvement in progression free survival (PFS) in patients with recurrent glioblastoma (GBM) treated with re-irradiation, compared to target volume delineation based on T1Gd-MRI. The target sample size is 200 randomized patients with a 1:1 allocation ratio to both arms. The primary endpoint (PFS) is determined by serial MRI scans, supplemented by AA-PET-scans and/or biopsy/surgery if suspicious of progression. Secondary endpoints include overall survival (OS), locally controlled survival (time to local progression or death), volumetric assessment of GTV delineated by either method, topography of progression in relation to MRIor PET-derived target volumes, rate of long term survivors (> 1 year), localization of necrosis after re-irradiation, quality of life (QoL) assessed by the EORTC QLQ-C15 PAL questionnaire, evaluation of safety of FET-application in AA-PET imaging and toxicity of re-irradiation. Discussion: This is a protocol of a randomized phase II trial designed to test a new strategy of radiotherapy target volume delineation for improving the outcome of patients with recurrent GBM. Moreover, the trial will help to develop a standardized methodology for the integration of AA-PET and other imaging biomarkers in radiation treatment planning. Trial registration: The GLIAA trial is registered with ClinicalTrials.gov (NCT01252459, registration date 02.12.2010), German Clinical Trials Registry (DRKS00000634, registration date 10.10.2014), and European Clinical Trials Database (EudraCT-No. 2012-001121-27, registration date 27.02.2012)
Approximate probabilistic verification of hybrid systems
Hybrid systems whose mode dynamics are governed by non-linear ordinary
differential equations (ODEs) are often a natural model for biological
processes. However such models are difficult to analyze. To address this, we
develop a probabilistic analysis method by approximating the mode transitions
as stochastic events. We assume that the probability of making a mode
transition is proportional to the measure of the set of pairs of time points
and value states at which the mode transition is enabled. To ensure a sound
mathematical basis, we impose a natural continuity property on the non-linear
ODEs. We also assume that the states of the system are observed at discrete
time points but that the mode transitions may take place at any time between
two successive discrete time points. This leads to a discrete time Markov chain
as a probabilistic approximation of the hybrid system. We then show that for
BLTL (bounded linear time temporal logic) specifications the hybrid system
meets a specification iff its Markov chain approximation meets the same
specification with probability . Based on this, we formulate a sequential
hypothesis testing procedure for verifying -approximately- that the Markov
chain meets a BLTL specification with high probability. Our case studies on
cardiac cell dynamics and the circadian rhythm indicate that our scheme can be
applied in a number of realistic settings
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