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Cellular theory

Gaia Palmini, Roberto Zonefrati, Carmelo Mavilia, Alessandra Aldinucci, Ettore Luzi, Francesca Marini, Alessandro Franchi, Rodolfo Capanna, Annalisa Tanini, Maria Luisa Brandi
The current improvements in therapy against osteosarcoma (OS) have prolonged the lives of cancer patients, but the survival rate of five years remains poor when metastasis has occurred. The Cancer Stem Cell (CSC) theory holds that there is a subset of tumor cells within the tumor that have stem-like characteristics, including the capacity to maintain the tumor and to resist multidrug chemotherapy. Therefore, a better understanding of OS biology and pathogenesis is needed in order to advance the development of targeted therapies to eradicate this particular subset and to reduce morbidity and mortality among patients...
October 14, 2016: Journal of Visualized Experiments: JoVE
Thomas D Pollard
No abstract text is available yet for this article.
October 18, 2016: Biophysical Journal
J E LeDoux, J Moscarello, R Sears, V Campese
Research on avoidance conditioning began in the late 1930s as a way to use laboratory experiments to better understand uncontrollable fear and anxiety. Avoidance was initially conceived of as a two-factor learning process in which fear is first acquired through Pavlovian aversive conditioning (so-called fear conditioning), and then behaviors that reduce the fear aroused by the Pavlovian conditioned stimulus are reinforced through instrumental conditioning. Over the years, criticisms of both the avoidance paradigm and the two-factor fear theory arose...
October 18, 2016: Molecular Psychiatry
Richard A Gray, Pras Pathmanathan
Elucidating the underlying mechanisms of fatal cardiac arrhythmias requires a tight integration of electrophysiological experiments, models, and theory. Existing models of transmembrane action potential (AP) are complex (resulting in over parameterization) and varied (leading to dissimilar predictions). Thus, simpler models are needed to elucidate the "minimal physiological requirements" to reproduce significant observable phenomena using as few parameters as possible. Moreover, models have been derived from experimental studies from a variety of species under a range of environmental conditions (for example, all existing rabbit AP models incorporate a formulation of the rapid sodium current, INa, based on 30 year old data from chick embryo cell aggregates)...
October 2016: PLoS Computational Biology
Miranda C Staples, Chitra D Mandyam
Alcohol use disorder currently affects approximately 18 million Americans, with at least half of these individuals having significant cognitive impairments subsequent to their chronic alcohol use. This is most widely apparent as frontal cortex-dependent cognitive dysfunction, where executive function and decision-making are severely compromised, as well as hippocampus-dependent cognitive dysfunction, where contextual and temporal reasoning are negatively impacted. This review discusses the relevant clinical literature to support the theory that cognitive recovery in tasks dependent on the prefrontal cortex and hippocampus is temporally different across extended periods of abstinence from alcohol...
2016: Frontiers in Psychiatry
Kevin R Pilkiewicz, Michael L Mayo
The internal biochemical state of a cell is regulated by a vast transcriptional network that kinetically correlates the concentrations of numerous proteins. Fluctuations in protein concentration that encode crucial information about this changing state must compete with fluctuations caused by the noisy cellular environment in order to successfully transmit information across the network. Oftentimes, one protein must regulate another through a sequence of intermediaries, and conventional wisdom, derived from the data processing inequality of information theory, leads us to expect that longer sequences should lose more information to noise...
September 2016: Physical Review. E
Doron Shkolnik, Hillel Fromm
Optimization of water foraging by plants is partially achieved by the ability of roots to direct growth towards high water potential, a phenomenon termed hydrotropism. In contrast to gravitropism and phototropism, which require auxin redistribution, as suggested by the Cholodny-Went theory, hydrotropism is not mediated by the phytohormone auxin, which raises questions about the mechanism underlying this tropic response. Here we specify the open questions in this field of research and discuss the possible interactions of abscisic acid, calcium and reactive oxygen species as part of a dynamic system of sensing water potential in the root tip, transmission of the signal to the root elongation zone and promoting root curvature towards water...
November 2016: Plant Science: An International Journal of Experimental Plant Biology
Marzena Ułamek-Kozioł, Ryszard Pluta, Sławomir Januszewski, Janusz Kocki, Anna Bogucka-Kocka, Stanisław J Czuczwar
We review the Alzheimer-related expression of genes following brain ischemia as risk factors for late-onset of sporadic Alzheimer's disease and their role in Alzheimer's disease ischemia-reperfusion pathogenesis. More recent advances in understanding ischemic etiology of Alzheimer's disease have revealed dysregulation of Alzheimer-associated genes including amyloid protein precursor, β-secretase, presenilin 1 and 2, autophagy, mitophagy and apoptosis. We review the relationship between these genes dysregulated by brain ischemia and the cellular and neuropathological characteristics of Alzheimer's disease...
September 5, 2016: Pharmacological Reports: PR
Jérôme R D Soiné, Nils Hersch, Georg Dreissen, Nico Hampe, Bernd Hoffmann, Rudolf Merkel, Ulrich S Schwarz
Animal cells use traction forces to sense the mechanics and geometry of their environment. Measuring these traction forces requires a workflow combining cell experiments, image processing and force reconstruction based on elasticity theory. Such procedures have already been established mainly for planar substrates, in which case one can use the Green's function formalism. Here we introduce a workflow to measure traction forces of cardiac myofibroblasts on non-planar elastic substrates. Soft elastic substrates with a wave-like topology were micromoulded from polydimethylsiloxane and fluorescent marker beads were distributed homogeneously in the substrate...
October 6, 2016: Interface Focus
John S Torday, William B Miller
A well-developed theory of evolutionary biology requires understanding of the origins of life on Earth. However, the initial conditions (ontology) and causal (epistemology) bases on which physiology proceeded have more recently been called into question, given the teleologic nature of Darwinian evolutionary thinking. When evolutionary development is focused on cellular communication, a distinctly different perspective unfolds. The cellular communicative-molecular approach affords a logical progression for the evolutionary narrative based on the basic physiologic properties of the cell...
October 2016: International Journal of Astrobiology
Ewan Henry, Stefan H Holm, Zunmin Zhang, Jason P Beech, Jonas O Tegenfeldt, Dmitry A Fedosov, Gerhard Gompper
Recent advances in cell sorting aim at the development of novel methods that are sensitive to various mechanical properties of cells. Microfluidic technologies have a great potential for cell sorting; however, the design of many micro-devices is based on theories developed for rigid spherical particles with size as a separation parameter. Clearly, most bioparticles are non-spherical and deformable and therefore exhibit a much more intricate behavior in fluid flow than rigid spheres. Here, we demonstrate the use of cells' mechanical and dynamical properties as biomarkers for separation by employing a combination of mesoscale hydrodynamic simulations and microfluidic experiments...
October 6, 2016: Scientific Reports
Mark P Jackson, Asif Rahman, Belen Lafon, Gregory Kronberg, Doris Ling, Lucas C Parra, Marom Bikson
The objective of this review is to summarize the contribution of animal research using direct current stimulation (DCS) to our understanding of the physiological effects of transcranial direct current stimulation (tDCS). We comprehensively address experimental methodology in animal studies, broadly classified as: (1) transcranial stimulation; (2) direct cortical stimulation in vivo and (3) in vitro models. In each case advantages and disadvantages for translational research are discussed including dose translation and the overarching "quasi-uniform" assumption, which underpins translational relevance in all animal models of tDCS...
September 10, 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Dhrubajyoti Gogoi, Vishwa Jyoti Baruah, Amrita Kashyap Chaliha, Bibhuti Bhushan Kakoti, Diganta Sarma, Alak Kumar Buragohain
Human epidermal growth factor receptor 2 (HER2) is one of the four members of the epidermal growth factor receptor (EGFR) family and is expressed to facilitate cellular proliferation across various tissue types. Therapies targeting HER2, which is a transmembrane glycoprotein with tyrosine kinase activity, offer promising prospects especially in breast and gastric/gastroesophageal cancer patients. Persistence of both primary and acquired resistance to various routine drugs/antibodies is a disappointing outcome in the treatment of many HER2 positive cancer patients and is a challenge that requires formulation of new and improved strategies to overcome the same...
September 27, 2016: Journal of Theoretical Biology
Negin Malekian, Jafar Habibi, Mohammad Hossein Zangooei, Hojjat Aghakhani
BACKGROUND AND OBJECTIVE: There are many cells with various phenotypic behaviors in cancer interacting with each other. For example, an apoptotic cell may induce apoptosis in adjacent cells. A living cell can also protect cells from undergoing apoptosis and necrosis. These survival and death signals are propagated through interaction pathways between adjacent cells called gap junctions. The function of these signals depends on the cellular context of the cell receiving them. For instance, a receiver cell experiencing a low level of oxygen may interpret a received survival signal as an apoptosis signal...
November 2016: Computer Methods and Programs in Biomedicine
Marc Pilon
Fundamental questions remain unresolved in diabetes: What is the actual mechanism of glucose toxicity? Why is there insulin resistance in type 2 diabetes? Why do diets rich in sugars or saturated fatty acids increase the risk of developing diabetes? Studying the C. elegans homologs of the anti-diabetic adiponectin receptors (AdipoR1 and AdipoR2) has led us to exciting new discoveries and to revisit what may be termed "The Membrane Theory of Diabetes". We hypothesize that excess saturated fatty acids (obtained through a diet rich in saturated fats or through conversion of sugars into saturated fats via lipogenesis) leads to rigid cellular membranes that in turn impair insulin signalling, glucose uptake and blood circulation, thus creating a vicious cycle that contributes to the development of overt type 2 diabetes...
September 27, 2016: Lipids in Health and Disease
Ziwei Dai, Jason W Locasale
Quantitative and qualitative knowledge of metabolic rates (i.e. fluxes) over a metabolic network and in specific cellular compartments gives insights into the regulation of metabolism and helps to understand the contribution of metabolic alterations to pathology. In this review we introduce methodology to resolve metabolic fluxes from stable isotope labeling and relevant techniques in model development, model simplification, flux uncertainty analysis and experimental design that together is termed metabolic flux analysis...
September 22, 2016: Metabolic Engineering
Jose V Lafuente, G Bermudez, L Camargo-Arce, S Bulnes
Cerebral syndromes related to high altitude exposure are becoming more frequent as the number of trips to high altitudes has increased in the last decade. The commonest symptom is headache, followed by acute mountain sickness (AMS) and high-altitude cerebral edema (HACE), which can be fatal. The pathophysiology of these syndromes is not fully comprehended. The classical "tight-fit hypothesis" defends the fact that there are some anatomical variations that would obstruct the sinovenous outflow and worsen the vasogenic edema and intracranial hypertension reactive to hypoxia...
September 20, 2016: CNS & Neurological Disorders Drug Targets
M A Birch-Machin, A Bowman
Oxidative stress is the resultant damage due to redox imbalances (increase in destructive free radicals [reactive oxygen species (ROS)] and reduction in antioxidant protection/pathways) and is linked to ageing in many tissues including skin. In ageing skin there are bioenergetic differences between keratinocytes and fibroblasts which provide a potential ageing biomarker. The differences in skin bioenergy are part of the mitochondrial theory of ageing which remains one of the most widely accepted ageing theories describing subsequent increasing free radical generation...
October 2016: British Journal of Dermatology
Przemysław Krawczyk, Beata Jędrzejewska, Marek Pietrzak, Tomasz Janek
In this study, the 4-(1H-phenanthro[9,10-d]-imidazol-2-yl)-benzaldehyde (PB1) was investigated as a fluorescent dye. For this reason, the spectroscopic properties in different solvents were thoroughly studied. The experimental data were supported by quantum-chemical calculations using density functional theory. Measurements and theoretical calculations showed that PB1 dye is characterized by the non-monotonic solvatochromism, strongly polar charge transfer excited state, large Stokes' shift, high fluorescence quantum yield and high fluorescence lifetime...
September 19, 2016: Journal of Photochemistry and Photobiology. B, Biology
Manon Fagniart, Christine Reynaert, Denis Jacques, Bries Lepièce, Nicolas Zdanowicz
BACKGROUND: Exposure to stress modifies the humoral and cellular immunity by the activation of the hypothalamic-pituitary-adrenal axis. On one hand, this psycho-immunological theory allows the analyse of links between immunity and depression. On the other hand, the correlation between the immune response, the clinical expression in major depressive disorder (MDD) and the gender was proven. Our analysis evaluates the influence of the gender and the level of depression severity on the cellular immune response associated with it...
September 2016: Psychiatria Danubina
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