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Theoretical Biology & Medical Modelling

Valentina Clamer, Ilaria Dorigatti, Laura Fumanelli, Caterina Rizzo, Andrea Pugliese
BACKGROUND: Epidemic models are being extensively used to understand the main pathways of spread of infectious diseases, and thus to assess control methods. Schools are well known to represent hot spots for epidemic spread; hence, understanding typical patterns of infection transmission within schools is crucial for designing adequate control strategies. The attention that was given to the 2009 A/H1N1pdm09 flu pandemic has made it possible to collect detailed data on the occurrence of influenza-like illness (ILI) symptoms in two primary schools of Trento, Italy...
October 12, 2016: Theoretical Biology & Medical Modelling
Thomas Hauser, Jennifer Adam, Henry Schulz
No abstract text is available yet for this article.
2016: Theoretical Biology & Medical Modelling
Shaji Krishnan, Henk F J Hendriks, Merete L Hartvigsen, Albert A de Graaf
BACKGROUND: An artificial neural network approach was chosen to model the outcome of the complex signaling pathways in the gastro-intestinal tract and other peripheral organs that eventually produce the satiety feeling in the brain upon feeding. METHODS: A multilayer feed-forward neural network was trained with sets of experimental data relating concentration-time courses of plasma satiety hormones to Visual Analog Scales (VAS) scores. The network successfully predicted VAS responses from sets of satiety hormone data obtained in experiments using different food compositions...
2016: Theoretical Biology & Medical Modelling
Felix Scholkmann
Coordinated interaction of single cells by cell-to-cell communication (signalling) enables complex behaviour necessary for the functioning of multicellular organisms. A quite newly discovered cell-to-cell signalling mechanism relies on nanotubular cell-co-cell connections, termed "membrane nanotubes" (MNTs). The present paper presents the hypothesis that mitochondria inside MNTs can form a connected structure (mitochondrial network) which enables the exchange of energy and signals between cells. It is proposed that two modes of energy and signal transmission may occur: electrical/electrochemical and electromagnetic (optical)...
2016: Theoretical Biology & Medical Modelling
Toshikazu Kuniya, Hideki Sano
BACKGROUND: In mathematical epidemiology, age-structured epidemic models have usually been formulated as the boundary-value problems of the partial differential equations. On the other hand, in engineering, the backstepping method has recently been developed and widely studied by many authors. METHODS: Using the backstepping method, we obtained a boundary feedback control which plays the role of the threshold criteria for the prediction of increase or decrease of newly infected population...
2016: Theoretical Biology & Medical Modelling
Xu-Sheng Zhang
BACKGROUND: One common observation in infectious diseases caused by multi-strain pathogens is that both the incidence of all infections and the relative fraction of infection with each strain oscillate with time (i.e., so-called Epidemic cycling). Many different mechanisms have been proposed for the pervasive nature of epidemic cycling. Nevertheless, the two facts that people contact each other through a network rather than following a simple mass-action law and most infectious diseases involve multiple strains have not been considered together for their influence on the epidemic cycling...
2016: Theoretical Biology & Medical Modelling
Matteo Gori, Irene Donato, Elena Floriani, Ilaria Nardecchia, Marco Pettini
BACKGROUND: This study is mainly motivated by the need of understanding how the diffusion behavior of a biomolecule (or even of a larger object) is affected by other moving macromolecules, organelles, and so on, inside a living cell, whence the possibility of understanding whether or not a randomly walking biomolecule is also subject to a long-range force field driving it to its target. METHOD: By means of the Continuous Time Random Walk (CTRW) technique the topic of random walk in random environment is here considered in the case of a passively diffusing particle among randomly moving and interacting obstacles...
2016: Theoretical Biology & Medical Modelling
Hiroki Masui, Itsuki Kakitani, Shumpei Ujiyama, Kazuyoshi Hashidate, Masataka Shiono, Kazue Kudo
BACKGROUND: Dengue is a common mosquito-borne viral disease epidemic especially in tropical and sub-tropical regions where water sanitation is not substantially controlled. However, dengue epidemics sometimes occur in non-tropical urban cities with substantial water sanitary control. Using a mathematical model, we investigate what conditions can be important for a dengue epidemic to occur in an urban city such as Tokyo, where vectors are active only in summer and there are little number of vectors around hosts...
2016: Theoretical Biology & Medical Modelling
Natalie K Gordon, Richard Gordon
The cell state splitter is a membraneless organelle at the apical end of each epithelial cell in a developing embryo. It consists of a microfilament ring and an intermediate filament ring subtending a microtubule mat. The microtubules and microfilament ring are in mechanical opposition as in a tensegrity structure. The cell state splitter is bistable, perturbations causing it to contract or expand radially. The intermediate filament ring provides metastability against small perturbations. Once this snap-through organelle is triggered, it initiates signal transduction to the nucleus, which changes gene expression in one of two readied manners, causing its cell to undergo a step of determination and subsequent differentiation...
2016: Theoretical Biology & Medical Modelling
Jorge Reyes-Silveyra, Armin R Mikler
BACKGROUND: In recent epidemiological models, immunity is incorporated as a simplified value that determines the capacity of an individual to become infected or to transmit the disease. Moreover, the quality of the immune response determines the chances of infection and the length of time an individual is capable to infect others. We present a model that incorporates individuals' immune responses to, further, examine the role of the collective immune response of individuals in a population during an infectious outbreak...
2016: Theoretical Biology & Medical Modelling
Vahid Rezania, Dennis Coombe, Jack A Tuszynski
BACKGROUND: One of the major issues in current pharmaceutical development is potential hepatotoxicity and drug-induced liver damage. This is due to the unique metabolic processes performed in the liver to prevent accumulation of a wide range of chemicals in the blood. Recently, we developed a physiologically-based lattice model to address the transport and metabolism of drugs in the liver lobule (liver functional unit). METHOD: In this paper, we extend our idealized model to consider structural and spatial variability in two and three dimensions...
2016: Theoretical Biology & Medical Modelling
Yanjun Li, Carson C Chow, Amber B Courville, Anne E Sumner, Vipul Periwal
BACKGROUND: Quantitative evaluation of insulin regulation on plasma glucose and free fatty acid (FFA) in response to external glucose challenge is clinically important to assess the development of insulin resistance (World J Diabetes 1:36-47, 2010). Mathematical minimal models (MMs) based on insulin modified frequently-sampled intravenous glucose tolerance tests (IM-FSIGT) are widely applied to ascertain an insulin sensitivity index (IEEE Rev Biomed Eng 2:54-96, 2009). Furthermore, it is important to investigate insulin regulation on glucose and FFA in postprandial state as a normal physiological condition...
2016: Theoretical Biology & Medical Modelling
Nicolas Carels, Lizânia Borges Spinassé, Tatiana Martins Tilli, Jack Adam Tuszynski
In this review, we report on breast cancer's molecular features and on how high throughput technologies are helping in understanding the dynamics of tumorigenesis and cancer progression with the aim of developing precision medicine methods. We first address the current state of the art in breast cancer therapies and challenges in order to progress towards its cure. Then, we show how the interaction of high-throughput technologies with in silico modeling has led to set up useful inferences for promising strategies of target-specific therapies with low secondary effect incidence for patients...
2016: Theoretical Biology & Medical Modelling
Yoichi Watanabe, Erik L Dahlman, Kevin Z Leder, Susanta K Hui
BACKGROUND: Mathematical modeling of biological processes is widely used to enhance quantitative understanding of bio-medical phenomena. This quantitative knowledge can be applied in both clinical and experimental settings. Recently, many investigators began studying mathematical models of tumor response to radiation therapy. We developed a simple mathematical model to simulate the growth of tumor volume and its response to a single fraction of high dose irradiation. The modelling study may provide clinicians important insights on radiation therapy strategies through identification of biological factors significantly influencing the treatment effectiveness...
2016: Theoretical Biology & Medical Modelling
Jitsuki Sawamura, Shigeru Morishita, Jun Ishigooka
BACKGROUND: Previously, we applied basic group theory and related concepts to scales of measurement of clinical disease states and clinical findings (including laboratory data). To gain a more concrete comprehension, we here apply the concept of matrix representation, which was not explicitly exploited in our previous work. METHODS: Starting with a set of orthonormal vectors, called the basis, an operator Rj (an N-tuple patient disease state at the j-th session) was expressed as a set of stratified vectors representing plural operations on individual components, so as to satisfy the group matrix representation...
2016: Theoretical Biology & Medical Modelling
Ryan C Kennedy, Glen Ep Ropella, C Anthony Hunt
BACKGROUND: Mechanistic explanations of cell-level phenomena typically adopt an observer perspective. Explanations developed from a cell's perspective may offer new insights. Agent-based models lend themselves to model from an individual perspective, and existing agent-based models generally utilize a regular lattice-based environment. A framework which utilizes a cell's perspective in an off-lattice environment could improve the overall understanding of biological phenomena. RESULTS: We present an agent-based, discrete event framework, with a demonstrative focus on biomimetic agents...
2016: Theoretical Biology & Medical Modelling
Richard J Strilka, Mamie C Stull, Michael S Clemens, Stewart C McCaver, Scott B Armen
BACKGROUND: The critically ill can have persistent dysglycemia during the "subacute" recovery phase of their illness because of altered gene expression; it is also not uncommon for these patients to receive continuous enteral nutrition during this time. The optimal short-acting subcutaneous insulin therapy that should be used in this clinical scenario, however, is unknown. Our aim was to conduct a qualitative numerical study of the glucose-insulin dynamics within this patient population to answer the above question...
2016: Theoretical Biology & Medical Modelling
Zhi Li, Hongyan Cao, Yuehua Cui, Yanbo Zhang
BACKGROUND: DNA sequence can be viewed as an unknown language with words as its functional units. Given that most sequence alignment algorithms such as the motif discovery algorithms depend on the quality of background information about sequences, it is necessary to develop an ab initio algorithm for extracting the "words" based only on the DNA sequences. METHODS: We considered that non-uniform distribution and integrity were two important features of a word, based on which we developed an ab initio algorithm to extract "DNA words" that have potential functional meaning...
2016: Theoretical Biology & Medical Modelling
Kolade M Owolabi, Kailash C Patidar
BACKGROUND: The study of dynamic relationship between a multi-species models has gained a huge amount of scientific interest over the years and will continue to maintain its dominance in both ecology and mathematical ecology in the years to come due to its practical relevance and universal existence. Some of its emergence phenomena include spatiotemporal patterns, oscillating solutions, multiple steady states and spatial pattern formation. METHODS: Many time-dependent partial differential equations are found combining low-order nonlinear with higher-order linear terms...
2016: Theoretical Biology & Medical Modelling
Robert Law, Michael Levin
BACKGROUND: Bioelectric gradients among all cells, not just within excitable nerve and muscle, play instructive roles in developmental and regenerative pattern formation. Plasma membrane resting potential gradients regulate cell behaviors by regulating downstream transcriptional and epigenetic events. Unlike neurons, which fire rapidly and typically return to the same polarized state, developmental bioelectric signaling involves many cell types stably maintaining various levels of resting potential during morphogenetic events...
October 15, 2015: Theoretical Biology & Medical Modelling
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