Theoretical Biology and Medical Modelling This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Rate-dependent Ca2+ signalling underlying the force-frequency response in rat ventricular myocytes: A coupled electromechanical modeling study
Conclusions: Our model provides mechanistic biophysically based explanations for the rate-dependence of CICR, generating useful and testable hypotheses. Although rat ventricular myocytes exhibit a positive peak FFR in the presence/absence of beta-adrenergic stimulation, they show a characteristic increase in the positive slope in FFR due to the presence of Norepinephrine or Isoproterenol. Our study identifies cAMP-mediated stimulation, and rate-dependent CaMKII-mediated up-regulation of ICa;L as the key mechanisms underlying the aforementioned positive FFR. (Source: Theoretical Biology and Medical Modelling)
Source: Theoretical Biology and Medical Modelling - September 10, 2013 Category: Biomedical Science Authors: Abhilash KrishnaMiguel ValderrabanoPhilip PaladeJohn Clark Source Type: research

Computational simulation of a new system modelling ions electromigration through biological membranes
Conclusions: We give numerical simulations obtained for different popular models of enzymatic reaction which were compared to those obtained in literature on systems of ordinary differential equations. The results obtained show a complete agreement between the two modellings. Furthermore, various numerical experiments are presented to confirm the accuracy, efficiency and stability of the proposed method. In particular, we show that the scheme is unconditionally stable and second-order accurate in space. (Source: Theoretical Biology and Medical Modelling)
Source: Theoretical Biology and Medical Modelling - September 5, 2013 Category: Biomedical Science Authors: Noureddine AlaaHamid Lefraich Source Type: research

Computational simulation of a new system modelling ions electromigration through biological membranes
Conclusions;We give numerical simulations obtained for different popular models of enzymatic reaction whichwere compared to those obtained in literature on systems of ordinary differential equations. Theresults obtained show a complete agreement between the two modellings. Furthermore, various numericalexperiments are presented to confirm the accuracy, efficiency and stability of the proposedMethodIn particular, we show that the scheme is unconditionally stable and second-order accuratein space. (Source: Theoretical Biology and Medical Modelling)
Source: Theoretical Biology and Medical Modelling - September 5, 2013 Category: Biomedical Science Authors: Noureddine AlaaHamid Lefraich Source Type: research

A physiologically-based flow network model for hepatic drug elimination I: regular lattice lobule model
We develop a physiologically-based lattice model for the transport and metabolism of drugs in the called the lobule. In contrast to earlier studies, we have emphasized the dominant role of convection in well-vascularized tissue with a given structure. Estimates of convective, diffusive and reaction contributions are given. We have compared drug concentration levels observed exiting the lobule with their predicted detailed distribution inside the lobule, assuming that most often the former is accessible information while the latter is not. (Source: Theoretical Biology and Medical Modelling)
Source: Theoretical Biology and Medical Modelling - September 5, 2013 Category: Biomedical Science Authors: Vahid RezaniaRebeccah MarshDennis CoombeJack Tuszynski Source Type: research

A physiologically-based flow network model for hepatic drug elimination II: variable lattice lobule models
We extend a physiologically-based lattice model for the transport and metabolism of drugs in the liver lobule (liver functional unit) to consider structural and spatial variability. We compare predicted drug concentration levels observed exiting the lobule with their detailed distribution inside the lobule, and indicate the role that structural variation has on these results. Liver zonation and its role on drug metabolism represent another aspect of structural inhomogeneity that we consider here. Since various liver diseases can be thought to produce such structural variations, our analysis gives insight into the role of d...
Source: Theoretical Biology and Medical Modelling - September 5, 2013 Category: Biomedical Science Authors: Vahid RezaniaRebeccah MarshDennis CoombeJack Tuszynski Source Type: research

Linking neuronal brain activity to the glucose metabolism
Conclusions: The hypothesis of the central role of the brain in whole body energy homeostasis as active controller is supported. (Source: Theoretical Biology and Medical Modelling)
Source: Theoretical Biology and Medical Modelling - August 29, 2013 Category: Biomedical Science Authors: Britta GöbelKerstin OltmannsMatthias Chung Source Type: research

Identification of novel PTPRQ phosphatase inhibitors based on the virtual screening with docking simulations
Protein tyrosine phosphatase receptor type Q (PTPRQ) is an unusual PTP that has intrinsic dephosphorylating activity for various phosphatidyl inositides instead of phospho-tyrosine substrates. Although PTPRQ was known to be involved in the pathogenesis of obesity, no small-molecule inhibitor has been reported so far. Here we report six novel PTPRQ inhibitors identified with computer-aided drug design protocol involving the virtual screening with docking simulations and enzyme inhibition assay. These inhibitors exhibit moderate potencies against PTPRQ with the associated IC50 values ranging from 29 to 86 muM. Because the ne...
Source: Theoretical Biology and Medical Modelling - August 28, 2013 Category: Biomedical Science Authors: Hwangseo ParkKeum YuBonsu KuBo KimSeung Kim Source Type: research

Plasma volume expansion from the intravenous glucose tolerance test before and after hip replacement surgery
Conclusion: Hyperosmotic glucose translocated intracellular water to the plasma volume rather than to the entire extracellular fluid volume. The preferential re-distribution acts to dilute the plasma concentrations used to quantify insulin sensitivity and Ss-cell function from an IVGTT. The greater-than-expected plasma dilution lasted longer after than before surgery. (Source: Theoretical Biology and Medical Modelling)
Source: Theoretical Biology and Medical Modelling - August 26, 2013 Category: Biomedical Science Authors: Robert HahnThomas NyströmStefan Ljunggren Source Type: research

Mathematical modelling of spatio-temporal glioma evolution
Conclusions: Based on the experimental validation, as well as the evaluation by clinical experts, the proposed model may provide an essential tool for the patient-specific simulation of different tumor evolution scenarios and reliable prognosis of glioma spatio-temporal progression. (Source: Theoretical Biology and Medical Modelling)
Source: Theoretical Biology and Medical Modelling - July 24, 2013 Category: Biomedical Science Authors: Maria PapadogiorgakiPanagiotis KoliouXenofon KotsiakisMichalis Zervakis Source Type: research

Identification of novel modulators for ionotropic glutamate receptor, iGluA2 by in-silico screening
Background: Ionotropic glutamate receptors (iGluAs, IUPHAR nomenclature) are the major excitatory amino acid neurotransmitter receptors in the mammalian central nervous system (CNS). iGluAs are potential therapeutic drug targets for various neurological disorders including ischemia, epilepsy, Parkinson's and Alzheimer's diseases. The known iGluA modulators, cyclothiazide (CTZ), IDRA-21, and other benzothiadiazide derivatives (ALTZ, HCTZ, and CLTZ) bind to the ligand-binding domain of flip-form of iGluA2 at the dimer interface, thereby increasing steady-state activation by reducing desensitization. Methods: To discover new ...
Source: Theoretical Biology and Medical Modelling - July 15, 2013 Category: Biomedical Science Authors: Balasundaram Padmanabhan Source Type: research

Mechanisms behind the immediate effects of Roux-en-Y gastric bypass surgery on type 2 diabetes
Conclusions: Glycemia normalization followingRoux-en-Y gastric bypass is undoubtedly caused by a variety of mechanisms,which may include caloric restriction, enhanced GLP-1, and perhapsothers proposed in earlier papers onthis subject. However, the present results suggest that anotherpossible mechanism should be added to the list of candidates:enhanced production in the lower intestine of a substance whichopens an alternative insulin-independent pathway for glucose transport. (Source: Theoretical Biology and Medical Modelling)
Source: Theoretical Biology and Medical Modelling - July 13, 2013 Category: Biomedical Science Authors: Roland AllenTyler HughesJia Lerd NgRoberto OrtizMichel Abou GhantousOthmane BouhaliPhilippe FroguelAbdelilah Arredouani Source Type: research

Theoretical Biology and Medical Modelling: ensuring continued growth and future leadership
Theoretical biology encompasses a broad range of biological disciplines ranging from mathematical biology and biomathematics to philosophy of biology. Adopting a broad definition of "biology", Theoretical Biology and Medical Modelling, an open access journal, considers original research studies that focus on theoretical ideas and models associated with developments in biology and medicine. (Source: Theoretical Biology and Medical Modelling)
Source: Theoretical Biology and Medical Modelling - July 11, 2013 Category: Biomedical Science Authors: Hiroshi NishiuraEdward RietmanRongling Wu Source Type: research

On the role of resonance in drug failure under HIV treatment interruption
Background: The application of highly active antiretroviral therapy (HAART) against HIV can reduce and maintainviral load below detection limit in many patients. Continuous HAART, however, can have severe sideeffects. In this context, structured treatment interruptions (STI) were considered to be a promisingstrategy. However, using CD4 cell count to guide intermittent therapy starting and stopping points, theSMART study (strategies for management of antiretroviral therapy), revealed that STI were associatedwith increased risk of AIDS and other complications. Additionally, short-term periodic (e.g. oneweek on / one week off...
Source: Theoretical Biology and Medical Modelling - July 11, 2013 Category: Biomedical Science Authors: Leonardo OñaRoger D KouyosMichael LachmannSebastian Bonhoeffer Source Type: research

Tumor inhibitory T cell immunity may be largely a transplantation artifact not necessarily dependent upon a lack of Tregs
There exists a very large literature suggesting that T cells come in a variety of species and that without the action of Tregs tumors would seldom survive inhibition by T cell effectors. We believe that much of the evidence supporting the role of Tregs in cancer is compatible with a perhaps simpler hypothesis based upon the demonstration that that small quantities of effector T cells tend to stimulate tumors while larger quantities of seemingly the same cells are inhibitory (an hormesis-like effect). This possibility seems to destroy much of the need to postulate a role for T cell suppressors (Tregs) in cancer, but the exp...
Source: Theoretical Biology and Medical Modelling - June 25, 2013 Category: Biomedical Science Authors: Richmond PrehnLiisa Prehn Source Type: research

Multi-scale agent-based modeling on melanoma and its related angiogenesis analysis
Conclusions: Simulation results showed that the 3D model can represent key features of melanoma growth, angiogenesis, and its related micro-environment. The model can help cancer researchers understand the melanoma developmental mechanism. Drug synergism analysis suggested that interrupting the communications between melanoma cells and the related vasculatures can significantly increase the drug efficacy against tumor cells. (Source: Theoretical Biology and Medical Modelling)
Source: Theoretical Biology and Medical Modelling - June 21, 2013 Category: Biomedical Science Authors: Jun WangLe ZhangChenyang JingGang YeHulin WuHongyu MiaoYukun WuXiaobo Zhou Source Type: research