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Applied physiology

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https://www.readbyqxmd.com/read/28092496/the-effect-of-contrast-material-on-radiation-dose-at-ct-part-i-incorporation-of-contrast-material-dynamics-in-anthropomorphic-phantoms
#1
Pooyan Sahbaee, W Paul Segars, Daniele Marin, Rendon C Nelson, Ehsan Samei
Purpose To develop a method to incorporate the propagation of contrast material into computational anthropomorphic phantoms for estimation of organ dose at computed tomography (CT). Materials and Methods A patient-specific physiologically based pharmacokinetic (PBPK) model of the human cardiovascular system was incorporated into 58 extended cardiac-torso (XCAT) patient phantoms. The PBPK model comprised compartmental models of vessels and organs unique to each XCAT model. For typical injection protocols, the dynamics of the contrast material in the body were described according to a series of patient-specific iodine mass-balance differential equations, the solutions to which provided the contrast material concentration time curves for each compartment...
January 13, 2017: Radiology
https://www.readbyqxmd.com/read/28091567/quantifying-the-relative-contributions-of-different-solute-carriers-to-aggregate-substrate-transport
#2
Mehdi Taslimifar, Lalita Oparija, Francois Verrey, Vartan Kurtcuoglu, Ufuk Olgac, Victoria Makrides
Determining the contributions of different transporter species to overall cellular transport is fundamental for understanding the physiological regulation of solutes. We calculated the relative activities of Solute Carrier (SLC) transporters using the Michaelis-Menten equation and global fitting to estimate the normalized maximum transport rate for each transporter (Vmax). Data input were the normalized measured uptake of the essential neutral amino acid (AA) L-leucine (Leu) from concentration-dependence assays performed using Xenopus laevis oocytes...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28090276/overexpression-of-recombinant-human-teriparatide-rhpth-1-34-in-escherichia-coli-an-innovative-gene-fusion-approach
#3
Nahid Bakhtiari, Zahra Amini Bayat, Sepideh Sagharidouz, Mohsen Vaez
BACKGROUND: Parathyroid hormone is an 84-amino acid peptide secreted by the parathyroid glands. Its physiological role is maintenance of normal serum calcium level and bone remodeling. Biological activity of this hormone is related to N-terminal 1-34 amino acids. The recombinant form of hormone (1-34) has been approved for treatment of osteoporosis from 2002. In this study, a novel fusion partner has been developed for preparation of high yield recombinant 1-34 amino acids of hPTH. METHODS: Novel nucleotide cassette designed encoding a chimeric fusion protein comprising of a fusion partner consisting of a His-tag in N-terminal, 53 amino acids belong to Escherichia coli (E...
January 2017: Avicenna Journal of Medical Biotechnology
https://www.readbyqxmd.com/read/28089685/evaluation-of-drug-drug-interaction-potential-between-sacubitril-valsartan-lcz696-and-statins-using-a-physiologically-based-pharmacokinetic-model
#4
Wen Lin, Tao Ji, Heidi Einolf, Surya Ayalasomayajula, Tsu-Han Lin, Imad Hanna, Tycho Heimbach, Christopher Breen, Venkateswar Jarugula, Handan He
Sacubitril/valsartan (LCZ696) has been approved for the treatment of heart failure. Sacubitril is an in vitro inhibitor of OATPs. In clinical studies, LCZ696 increased atorvastatin Cmax by 1.7-fold and AUC by 1.3-fold, but had little or no effect on simvastatin or simvastatin acid exposure. A PBPK modelling approach was applied to explore the underlying mechanisms behind the statin-specific LCZ696 drug interaction observations. The model incorporated OATP-mediated clearance (CLint,T) for simvastatin and simvastatin acid to successfully describe the PK profiles of either analyte in the absence or presence of LCZ696...
January 12, 2017: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28088482/combined-spatiotemporal-ica-stica-for-continuous-and-dynamic-lag-structure-analysis-of-mreg-data
#5
Ville Raatikainen, Niko Huotari, Vesa Korhonen, Aleksi Rasila, Janne Kananen, Lauri Raitamaa, Tuija Keinänen, Jussi Kantola, Osmo Tervonen, Vesa Kiviniemi
This study investigated lag structure in the resting-state fMRI by applying a novel independent component (ICA) method to magnetic resonance encephalography (MREG) data. Briefly, the spatial ICA (sICA) was used for defining the frontal and back nodes of the default mode network (DMN), and the temporal ICA (tICA), which is enabled by the high temporal resolution of MREG (TR=100ms), was used to separate both neuronal and physiological components of these two spatial map regions. Subsequently, lag structure was investigated between the frontal (DMNvmpf) and posterior (DMNpcc) DMN nodes using both conventional method with all-time points and a sliding-window approach...
January 11, 2017: NeuroImage
https://www.readbyqxmd.com/read/28088071/discrete-quasi-linear-viscoelastic-damping-analysis-of-connective-tissues-and-the-biomechanics-of-stretching
#6
Behzad Babaei, Aaron J Velasquez-Mao, Stavros Thomopoulos, Elliot L Elson, Steven D Abramowitch, Guy M Genin
The time- and frequency-dependent properties of connective tissue define their physiological function, but are notoriously difficult to characterize. Well-established tools such as linear viscoelasticity and the Fung quasi-linear viscoelastic (QLV) model impose forms on responses that can mask true tissue behavior. Here, we applied a more general discrete quasi-linear viscoelastic (DQLV) model to identify the static and dynamic time- and frequency-dependent behavior of rabbit medial collateral ligaments. Unlike the Fung QLV approach, the DQLV approach revealed that energy dissipation is elevated at a loading period of ∼10s...
December 22, 2016: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28087676/the-longitudinal-study-of-aging-in-human-young-adults-knowledge-gaps-and-research-agenda
#7
Terrie E Moffitt, Daniel W Belsky, Andrea Danese, Richie Poulton, Avshalom Caspi
BACKGROUND: To prevent onset of age-related diseases and physical and cognitive decline, interventions to slow human aging and extend health span must eventually be applied to people while they are still young and healthy. Yet most human aging research examines older adults, many with chronic disease, and little is known about aging in healthy young humans. METHOD: This article explains how this knowledge gap is a barrier to extending health span and puts forward the case that geroscience should invest in researching the pace of aging in young adults...
February 2017: Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
https://www.readbyqxmd.com/read/28087529/resilience-dynamics-and-interactions-within-a-multi-species-exoelectrogenic-model-biofilm-community
#8
Anna Prokhorova, Katrin Sturm-Richter, Andreas Doetsch, Johannes Gescher
: Anode-associated multi-species exoelectrogenic biofilms are essential to the function of bioelectrochemical systems (BESs). The individual activities of anode associated organisms and physiological responses resulting from co-culturing are often hard to assess due to the high microbial diversity in these systems. Therefore, we developed a model multispecies biofilm of the three exoelectrogenic proteobacteria Shewanella oneidensis, Geobacter sulfurreducens and Geobacter metallireducens with the aim to study in detail the biofilm formation dynamics, the interactions between the organisms and the overall activity of an exoelectrogenic biofilm as a consequence of the applied anode potential...
January 13, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28086844/are-risk-predicting-models-useful-for-estimating-survival-of-patients-with-rheumatoid-arthritis-associated-interstitial-lung-disease
#9
Hanna M Nurmi, Minna K Purokivi, Miia S Kärkkäinen, Hannu-Pekka Kettunen, Tuomas A Selander, Riitta L Kaarteenaho
BACKGROUND: Risk predicting models have been applied in idiopathic pulmonary fibrosis (IPF), but still not validated in patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD). The purpose of this study was to test the suitability of three prediction models as well as individual lung function and demographic factors for evaluating the prognosis of RA-ILD patients. METHODS: Clinical and radiological data of 59 RA-ILD patients was re-assessed...
January 13, 2017: BMC Pulmonary Medicine
https://www.readbyqxmd.com/read/28081281/short-communication-validation-of-reference-genes-for-real-time-quantitative-pcr-in-tambaqui-colossoma-macropomum
#10
A R Nascimento, G F Silva, G F Gualberto, F L Almeida
Tambaqui, Colossoma macropomum, is the main native freshwater fish in Brazilian aquaculture. Therefore, intensive research pressure has been applied to the species to support new technologies for tambaqui farming. Molecular biology represents a tool that can be used to investigate every field of applied biology, from fish physiology to the effects of climate change. Based on the importance of reference genes for the relative or absolute quantification of gene transcripts, we cloned and sequenced three candidate reference genes in tambaqui (18S ribossomal RNA - 18s, glyceraldehyde-3-phosphate dehydrogenase - gapdh, and actin beta - β-actin), and validated a set of primers for each gene for use in real-time quantitative PCR...
December 23, 2016: Genetics and Molecular Research: GMR
https://www.readbyqxmd.com/read/28081189/global-gene-expression-analysis-of-cross-protected-phenotype-of-pectobacterium-atrosepticum
#11
Vladimir Gorshkov, Stanford Kwenda, Olga Petrova, Elena Osipova, Yuri Gogolev, Lucy N Moleleki
The ability to adapt to adverse conditions permits many bacterial species to be virtually ubiquitous and survive in a variety of ecological niches. This ability is of particular importance for many plant pathogenic bacteria that should be able to exist, except for their host plants, in different environments e.g. soil, water, insect-vectors etc. Under some of these conditions, bacteria encounter absence of nutrients and persist, acquiring new properties related to resistance to a variety of stress factors (cross-protection)...
2017: PloS One
https://www.readbyqxmd.com/read/28080976/respiratory-modulation-of-startle-eye-blink-a-new-approach-to-assess-afferent-signals-from-the-respiratory-system
#12
André Schulz, Thomas M Schilling, Claus Vögele, Mauro F Larra, Hartmut Schächinger
Current approaches to assess interoception of respiratory functions cannot differentiate between the physiological basis of interoception, i.e. visceral-afferent signal processing, and the psychological process of attention focusing. Furthermore, they typically involve invasive procedures, e.g. induction of respiratory occlusions or the inhalation of CO2-enriched air. The aim of this study was to test the capacity of startle methodology to reflect respiratory-related afferent signal processing, independent of invasive procedures...
November 19, 2016: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28079528/assessing-the-evolution-of-redundancy-synergy-of-spontaneous-variability-regulation-with-age
#13
Alberto Porta, Vlasta Bari, Beatrice De Maria, Natália Maria Perseguini, Juliana Milan, Patricia Rehder-Santos, Vinícius Minatel, Anielle Takahashi, Aparecida Catai
We exploited a model-based Wiener-Granger causality method in the information domain for the evaluation of the transfer entropy (TE) and interaction TE (ITE), the latter taken as a measure of the net balance between redundancy and synergy, to describe the interactions between the spontaneous variability of heart period (HP) and systolic arterial pressure (SAP) and the effect of respiration (R) on both variables. Cardiac control was typified via the genuine TE from SAP to HP, that from R to HP, and the ITE from SAP and R to HP, while vascular control was characterized via the genuine TE from HP to SAP, that from R to SAP, and the ITE from HP and R to SAP...
January 12, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28079493/ernst-mach-invents-a-new-sphygmograph
#14
Alexandre Métraux
Argument The sphygmograph as designed and tested by Jules-Étienne Marey - an apparatus destined to write pulse tracings on paper - revolutionized medical diagnostics in the early 1860s. Since the accuracy with which this device registered and objectified the pulse was controversial from the outset, the young scholar Ernst Mach (soon to become a leading theoretician and philosopher) decided to thoroughly examine Marey's sphygmograph. The investigation led to the invention of an alternative, truly Machian, sphygmograph...
December 2016: Science in Context
https://www.readbyqxmd.com/read/28079264/electromagnetic-computation-and-modeling-in-mri
#15
REVIEW
Xin Chen, Michael Steckner
Electromagnetic (EM) computational modeling is used extensively during the development of a Magnetic Resonance Imaging (MRI) scanner, its installation, and use. MRI, which relies on interactions between nuclear magnetic moments and the applied magnetic fields, uses a range of EM tools to optimize all of the magnetic fields required to produce the image. The main field magnet is designed to exacting specifications but challenges in manufacturing, installation, and use require additional tools to maintain target operational performance...
January 12, 2017: Medical Physics
https://www.readbyqxmd.com/read/28079030/neuromusculoskeletal-model-self-calibration-for-on-line-sequential-bayesian-moment-estimation
#16
Diana Ruiz Bueno, Luis Montano
OBJECTIVE: Neuromusculoskeletal models involve many subject-specific physiological parameters that need to be adjusted to adequately represent muscle properties. Traditionally, neuromusculoskeletal models have been calibrated with a forward-inverse dynamic optimization which is time-consuming and unfeasible for rehabilitation therapy. Non self-calibration algorithms have been applied to these models. To the best of our knowledge, the algorithm proposed in this work is the first on-line calibration algorithm for muscle models that allows a generic model to be adjusted to different subjects in a few steps...
January 12, 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28078981/resilience-to-alzheimer-s-disease-the-role-of-physical-activity
#17
Pedrinolla Anna, Schena Federico, Venturelli Massimo
BACKGROUND: Although Alzheimer's disease (AD) is a neurodegenerative pathology characterized by accumulation of β-amyloid plaques and neurofibrillary tangles at cerebral level, recent studies highlighted that AD might be the result of many altered physiological processes occurring at whole-organism level. The ability to adapt to stressors by "bending" but not "breaking" can be considered as "resilience". Individuals incline to withstand such pathophysiological challenges, can be considered more resilient than those that do not...
January 11, 2017: Current Alzheimer Research
https://www.readbyqxmd.com/read/28078471/effects-of-estrogen-on-esophageal-function-through-regulation-of-ca-2-related-proteins
#18
Kipung Kim, Dongoh Lee, Changhwan Ahn, Hee Young Kang, Beum-Soo An, Yeon Hee Seong, Eui-Bae Jeung
BACKGROUND: The calcium ion is important for physiological functions in all tissues and organs and essential to many vital functions, including hormone secretion and muscle contraction. The intracellular concentration of calcium is regulated by calcium related proteins such as CaBP-9k, PMCA1, and NCX1. In this study, we investigated the relationship between calcium regulation and esophageal functions such as mucin secretion and smooth muscle contraction. METHODS: To evaluate the influence of sex steroid hormones, immature rats were treated for 3 days with estradiol (E2), progesterone (P4), and their antagonists (ICI 182,780, and RU486)...
January 11, 2017: Journal of Gastroenterology
https://www.readbyqxmd.com/read/28077708/dynamic-shifts-in-large-scale-brain-network-balance-as-a-function-of-arousal
#19
Christina B Young, Gal Raz, Daphne Everaerd, Christian F Beckmann, Indira Tendolkar, Talma Hendler, Guillén Fernández, Erno J Hermans
: The ability to temporarily prioritize rapid and vigilant reactions over slower higher-order cognitive functions is essential for adaptive responding to threat. This reprioritization is believed to reflect shifts in resource allocation between large-scale brain networks that support these cognitive functions, including the salience and executive control networks. However, how changes in communication within and between such networks dynamically unfold as a function of threat-related arousal remains unknown...
January 11, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28077663/temporally-precise-control-of-single-neuron-spiking-by-juxtacellular-nanostimulation
#20
Maik Christopher Stüttgen, Lourens Jp Nonkes, Hans-Rüdiger Ap Geis, Paul H Tiesinga, Arthur R Houweling
Temporal patterns of action potentials influence a variety of activity-dependent intra- and inter-cellular processes and play an important role in theories of neural coding. Elucidating the mechanisms underlying these phenomena requires imposing spike trains with precisely defined patterns, but this has been challenging due to the limitations of existing stimulation techniques. Here we present a new nanostimulation method providing control over the action potential output of individual cortical neurons. Spikes are elicited through the juxtacellular application of short-duration fluctuating currents ('kurzpulses'), allowing for the sub-millisecond precise and reproducible induction of arbitrary patterns of action potentials at all physiologically relevant firing frequencies (<120 Hz), including minute-long spike trains recorded in freely moving animals...
January 11, 2017: Journal of Neurophysiology
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